This PDF file contains the front matter associated with SPIE Proceedings Volume 9917 including the Title Page, Copyright information, Table of Contents, Introduction (if any), and Conference Committee listing.

The histological structure of the rabbit parietal bone during its regeneration after fractional Er: YAG-laser (λ=2.94μm) treatment was investigated by hematoxylin and eosin (H&E) stain. In 48 days after fractional laser treatment, bone samples contained micro-cavities and fragments of necrotic tissue with empty cellular lacuna and coagulated protein of bone matrix. In this case, necrotic lesions appeared around the periphery of micro-cavities created by laser radiation. Fragmentation of detrital mass and partial substitution of micro-cavities with fatty bone marrow were observed in bone samples in 100 days after fractional laser treatment, in contrast to the earlier period. Partial filling of micro-cavities edges by fibrous tissue with presence of osteoblasts on their inner surface was observed in 100 days also, that indicates regenerative processes in the bone.

This study is aimed to define the extent of digital capillaroscopy possibilities for the quantification and estimation of microvascular abnormalities in type 2 diabetes mellitus (T2DM).

A total of 196 adult persons were enrolled in the study including the group of compensated T2DM (n = 52), decompensated diabetics (n = 68), and healthy volunteers (n = 76) with normal blood glucose and without signs of cardiovascular pathology.

All participants of the study were examined with the digital optical capillaroscope (“AET”, Russia). This instrument is equipped with an image-processing program allowing for quantifying the diameters of the arterial and venous segments of the capillaries and their ratio (coefficient of remodeling), perivascular zone size, capillary blood velocity, and the degree of arterial loops narrowing and the density of the capillary network. Also we estimated the relative amount of coil-shaped capillaries.

The study revealed significant difference in the capillary density and the remodeling coefficient in comparison of T2DM patients with non-diabetic individuals. Significant changes are found in the decompensated T2DM group compared to the compensated group of diabetic patients. Furthermore, the number of coil-shaped capillaries differed greatly in T2DM patients as compared to the healthy subjects. The study did not reveal any statistically significant differences in the capillary density between the patients with compensated and decompensated T2DM.

The digital optical capillaroscope equipped with the advanced image-processing algorithm opens up new possibilities for obtaining clinically important information on microvascular abnormalities in patients suffering from diabetes mellitus.

Red blood cells aggregating and disaggregating forces were measured in the autologous plasma and serum using the double-channeled optical tweezers. A significant, three-fold decrease of the both forces was observed in the serum compared to the plasma. The results of this study help to better assess the RBC aggregation mechanism.

Development of optical biopsy methods has a great interest for medical diagnostics. In clinical and experimental studies it is very important to analyze blood circulation quickly and accurately, thereby laser Doppler flowmetry (LDF) is widely used. UV laser-induced fluorescence spectroscopy (UV LIFS) is express highly sensitive and widely-spread method with no destructive impact, high excitation selectivity and the possibility to use in highly scattering media.

The goal of this work was to assess a correlation of UV laser-induced fluorescence spectroscopy and laser Doppler flowmetry parameters, and a possibility to identify or to differentiate various types of pathological changes in tissues according to their autofluorescence spectra.

Three groups of patients with diffuse (symptomatic) alopecia, androgenic alopecia, and focal alopecia have been tested. Each groups consisted of not less than 20 persons. The measurements have been done in the parietal and occipital regions of the sculls. We used the original automated spectrofluorimeter to record autofluorescence spectra, and standard laser Doppler flowmeter BLF-21 (Transonic Systems, Inc., USA) to analyze the basal levels of blood circulation.

Our results show that UV LIFS accurately distinguishes the zones with different types of alopecia. We found high correlation of the basal levels of blood circulation and the integrated intensity of autofluorescence in the affected tissue.

Protein glycation is accelerated under hyperglycemic conditions resulting to loss in the structure and biological functions of proteins. The transmission THz spectroscopy has been used for measuring of bovine serum albumin glycation dynamics. It was found that amplitude of albumin THz absorption depends on type of sugars and incubation time.

The paper is targeted to find the optimal mathematical model and the calibration algorithm for the industrial endoscope equipped with the prism-based attachable stereo adapter, which allows imaging from two different points by a single sensor. We consider the conventional calibration methods for the pinhole camera model with polynomial distortion approximation and compared them with the ray tracing model based on the vector form of Snell’s law. In order to evaluate each of the proposed models we have developed the software for the imitation of various calibration procedures using different types of calibration targets. We use the computer simulation to prove that the pinhole camera models, widely used in machine vision, are very limited for describing prism-based endoscopic measurement systems. Our analysis identified the main problems for these models, such as entrance pupil shift, non-homocentric beams and required number of coefficients for polynomial models and the iterative forward ray aiming for the ray-tracing model. The proposed technique is flexible and can also be used to test stability and convergence of the parameter estimation procedures and to compare calibration targets and strategies.

The aim of work was to study the morphological changes in transplanted liver tumors of rats after plasmonic photothermal therapy (PPTT). The gold nanorods functionalized with thiolated polyethylene glycol were injected intravenously to rats with transplanted liver cancer PC-1. A day after injection the tumors were irradiated by the infrared 808-nm diode laser. The withdrawal of the animals from the experiment and sampling of tumor tissue for morphological study were performed 24 hours after the laser exposure. The standard histological and immunohistochemical staining with antibodies to proliferation marker Ki-67 and apoptosis marker BAX were used for morphological study of transplanted tumors. The plasmonic photothermal therapy had pronounced damaging effect in rats with transplanted liver tumors expressed in degenerative and necrotic changes in the tumor cells. The decrease of proliferation marker Ki-67 and increase of expression of apoptosis marker BAX were observed in tumor cells after PPTT.

To date, the effect of housing temperature on tumor development in the immunocompetent mice has been studied on poorly immunogenic cancer models. Standard housing temperature 20–26°C was shown to cause chronic metabolic cold stress and promote tumor progression via suppression of the antitumor immune response, whereas a thermoneutral temperature 30-31°C was more preferable for normal metabolism of mice and inhibited tumor growth. Our work represents the first attempt to discover the potential effect of housing temperature on the development of highly immunogenic tumor. EGFP-expressing murine colon carcinoma CT26 generated in Balb/c mice was used as a tumor model. No statistically significant differences were shown in tumor incidences and growth rates at 20°С, 25°С and 30°С for non-modified CT26. Maintaining mice challenged with CT26-EGFP cells at 30°С led to complete inhibition of tumor development. In summary, we demonstrated that the housing temperature is important for the regulation of growth of highly immunogenic tumors in mice through antitumor immunity.

Numerical model for simulation of generation process in advanced pulse-periodic high-peak-power picosecond diode-pumped Nd:YAG and Nd:YLF lasers has been developed. The model adequately describes picosecond pulse formation governed by active and passive mode-locking, negative feedback and adjustable loss level in the oscillator cavity. Optical jitter of output pulses attributed to laser generation development from spontaneous noise level was evaluated using statistical analysis of calculation results. In the presented laser scheme, minimal jitter value on the level ~40 ps was estimated.

Here we studied the role of nitric oxide in cardiovascular regulation in male and female hypertensive rats under normal and stress conditions. We found that the severity of hypertension in females was lower than in males. Hypertensive females demonstrated more favorable pattern of cardiovascular responses to stress. Nitric oxide blockade by NG-nitro-L-arginine methyl ester (L-NAME) increased the mean arterial pressure and decreased the heart rate more effectively in females than in males. During stress, L-NAME modified the stress-induced cardiovascular responses more significantly in female compared with male groups. Our data show that hypertensive females demonstrated the more effective nitric oxide control of cardiovascular activity under normal and especially stress conditions than male groups. This sex differences may be important mechanism underlying greater in females vs. males stress-resistance of cardiovascular system and hypertension formation.

It was shown in the experience with 60 white mice that separate and combined effects of stress factors: noctidial lighting (800 lux), sodium nitrite (0.2% solution in water) and p-toluidine (with food) within 107 days causes a change in impedance value of erythrocytes at frequencies 1 Hz – 1MHz. Changes in the activity of intracellular aminotransferases, creatinine and urea were observed, indicating cardiotoxic and hepatotoxic effects.

In this work are presented the results of experimental studies of biological tissue implants using the method of Raman spectroscopy (RS). Raman spectra were obtained particularly biological tissue implants made by two different protocols. Were introduced optic coefficients, to monitor the content of the main components in bio tissue implants in the manufacturing process and to assess the quality of their processing on the selected protocol.

In the paper the mathematical model of kinetics of interaction of the injected compound with biological liquid flow has been described for different means of cells concentrations connected on packed cell volume. It is considered that biological liquid contains a three phases such as water, peptides and cells. At the time, the injected compound can interact with peptides and cells which are "trap" for him. The obtained distribution of the compound connects on changes of its fluorescence spectra. It is shown that fluorescence intensivity change is different at 560, 580 and 590 nm. The curves do not have monotonic nature. There is a sharp curves decline in the first few seconds, next, it are increasing. Curves inflection time slightly depends on the cells concentration and is 7-9 seconds. At the time stationary concentration significantly depends on this parameter in contrast to blood viscosity. As long s cells concentration is primarily mean of the packed cell volume, the model can be important for pharmacokinetics and preparations delivery. It can be also used for fluorescent biomedical diagnostics of cancer tumour.

The paper presents a mathematical model of linear and nonlinear processes occurring due to propagation of femtosecond laser pulses in vitreous of the human eye. By methods of numerical simulation, we have solved a nonlinear spectral equation describing dynamics of two-dimensional TE-polarized radiation. The solution was performed in a homogeneous isotropic medium with instantaneous cubic nonlinearity without using slowly varying envelope approximation. For simulation we used medium with parameters close to the optical media of the eye. The model of femtosecond radiation takes into account the dynamics of the process of dispersion pulse broadening in time and occurrence of self-focusing of the retina when passing through vitreous body of the eye. The dependence between pulse duration on the retina and duration of the input pulse was found, as well as the values of power density at which self-focusing occurs. It was shown that the main mechanism of radiation damage caused while using Ti-sapphire laser is photoionization. The results coincide with the results obtained by other scientists. They can be used to create Russian laser safety standards for femtosecond laser systems.

Volumetric fiber-optic thermal converter (VFOTC) formed on the end of the quartz fiber as a result of two-stage conversion of quartz and carbon by medical diode laser radiation with a wavelength of 980 nm is investigated both experimentally and theoretically. The geometrical dimensions of the converter are defined and the internal structure of the converter is studied by optical microscopy. The dependence of VFOTC temperature on exposure time of diode laser radiation with a wavelength of 980 nm and power of 1.0±0.1 W is obtained experimentally. The structural, optical and thermal model of VFOTC is proposed. Good correlation between the experimental and modeling results of laser heating of the converter is demonstrated.

Results of nevus, papilloma, dermatofibroma, and basal cell skin cancer in vivo removal by a 980±10 nm diode laser with "blackened" tip operating in continuous (CW) mode and automatic power control (APC) mode are presented. The collateral damage width and width of graze wound area around the collateral damage area were demonstrated. The total damage area width was calculated as sum of collateral damage width and graze wound area width. The mean width of total damage area reached 1.538±0.254 mm for patient group with nevus removing by 980 nm diode laser operating in CW mode, papilloma − 0.586±0.453 mm, dermatofibroma − 1.568±0.437 mm, and basal cell skin cancer − 1.603±0.613 mm. The mean width of total damage area reached 1.201±0.292 mm for patient group with nevus removing by 980 nm diode laser operating in APC mode, papilloma − 0.413±0.418 mm, dermatofibroma − 1.240±0.546 mm, and basal cell skin cancer − 1.204±0.517 mm. It was found that using APC mode decreases the total damage area width at removing of these nosological neoplasms of human skin, and decreases the width of graze wound area at removing of nevus and basal cell skin cancer. At the first time, the dynamic of output laser power and thermal signal during laser removal of nevus in CW and APC mode is presented. It was determined that output laser power during nevus removal for APC mode was 1.6±0.05 W and for CW mode – 14.0±0.1 W. This difference can explain the decrease of the total damage area width and width of graze wound area for APC mode in comparison with CW mode.

Laser welding device for biological tissue has been developed. The main device parts are the radiation system and adaptive thermal stabilization system of welding area. Adaptive thermal stabilization system provided the relation between the laser radiation intensity and the weld temperature. Using atomic force microscopy the structure of composite which is formed by the radiation of laser solder based on aqua- albuminous dispersion of multi-walled carbon nanotubes was investigated. AFM topograms nanocomposite solder are mainly defined by the presence of pores in the samples. In generally, the surface structure of composite is influenced by the time, laser radiation power and MWCNT concentration. Average size of backbone nanoelements not exceeded 500 nm. Bulk density of nanoelements was in the range 10⁶-10⁸ sm^-3. The data of welding temperature maintained during the laser welding process and the corresponding tensile strength values were obtained. Maximum tensile strength of the suture was reached in the range 50-55°C. This temperature and the pointwise laser welding technology (point area ~ 2.5mm) allows avoiding thermal necrosis of healthy section of biological tissue and provided reliable bonding construction of weld join. In despite of the fact that tensile strength values of the samples are in the range of 15% in comparison with unbroken strips of pigskin leather. This situation corresponds to the initial stage of the dissected tissue connection with a view to further increasing of the joint strength of tissues with the recovery of tissue structure; thereby achieved ratio is enough for a medical practice in certain cases.

Photodynamic therapy (PDT) is a potential tool for selective destruction of malignant brain tumors. However, not only malignant but also healthy neurons and glial cells may be damaged during PDT. Nitric oxide is an important modulator of cell viability and intercellular neuroglial communications. NO have been already shown to participate in PDT-induced injury of neurons and glial cells. As soluble guanylyl cyclase is the only known receptor for NO, we have studied the possible role of soluble guanylyl cyclase in the regulation of survival and death of neurons and surrounding glial cells under photo-oxidative stress induced by photodynamic treatment (PDT). The crayfish stretch receptor consisting of a single identified sensory neuron enveloped by glial cells is a simple but informative model object. It was photosensitized with alumophthalocyanine photosens (10 nM) and irradiated with a laser diode (670 nm, 0.4 W/cm²). Using inhibitory analysis we have shown that during PDT soluble guanylyl cyclase, probably, has proapoptotic and antinecrotic effect on the glial cells of the isolated crayfish stretch receptor. Proapoptotic effect of soluble guanylyl cyclase could be mediated by protein kinase G (PKG). Thus, the involvement of NO/sGC/cGMP/PKG signaling pathway in PDT-induced apoptosis of glial cells was indirectly demonstrated.

Ischemic tolerance determines resistance to lethal ischemia gained by a prior sublethal stimulus (i.e., preconditioning). We reproduced this effect in two variants. In vitro the preliminary short (5 s) photodynamic treatment (PDT) (photosensitizer Photosens, 10 nM, 30 min preincubation; laser: 670 nm, 100 mW/cm₂) significantly reduced the necrosis of neurons and glial cells in the isolated crayfish stretch receptor, which was caused by following 30-min PDT by 66% and 46%, respectively. In vivo PDT of the rat cerebral cortex with hydrophilic photosensitizer Rose Bengal (i.v. administration, laser irradiation: 532 nm, 60 mW/cm², 3 mm beam diameter, 30 min) caused occlusion of small brain vessels and local photothrombotic infarct (PTI). It is a model of ischemic stroke. Cerebral tissue edema and global necrosis of neurons and glial cells occurred in the infarction core, which was surrounded by a 1.5 mm transition zone, penumbra. The maximal pericellular edema, hypo- and hyperchromia of neurons were observed in penumbra 24 h after PTI. The repeated laser irradiation of the contralateral cerebral cortex also caused PTI but lesser as compared with single PDT. Preliminary unilateral PTI provided ischemic tolerance: at 14 day after second exposure the PTI volume significantly decreased by 24% than in the case of a single exposure. Sensorimotor deficits in PDT-treated rats was registered using the behavioral tests. The preliminary PTI caused the preconditioning effect.

In the present work the effectiveness of antioxidants quercetine (a pure chemical) and Gratiola officinalis extract, which is obtained by a new method of extraction from plant material, is investigated on the model of photodynamic haemolysis that is a rather convenient method to monitor the rate of cell membranes oxidative destruction. The effect of these antioxidants on the rate of photodynamic haemolysis is considered as a measure of membranoprotective efficiency.

Vasospastic disorders are a common class of rheumatic disease. These include syndromes such as vegetative dystonia, Raynaud's syndrome, vibration disease and rheumatoid arthritis among others. The aim of this work is to develop an original method of diagnosing the functional state of peripheral vessels of the fingers, based on the simultaneous recording of LDF- and thermograms during the occlusion test, for determining vascular disorders of rheumatological patients.

A diagnostic method was developed for assessing the functional state of the peripheral vessels of fingers, based on carrying out occlusion test in a thermally stabilized environment, with simultaneous recording of signals of laser Doppler flowmetry and skin thermometry. To verify the diagnostic value of the proposed method, a series of experiments were carried out on 41 rheumatological patients: 5 male and 36 females (average age 56.0±12.2 years). The most common diagnoses in the patient group were rheumatoid arthritis, arthrosis, gout and systemic lupus erythematosus. The laser analyser of blood microcirculation “LAKK-02” (SPE “LAZMA” Ltd, Russia) and a custom developed multi-channel thermometry device for low inertia thermometry were used for experimental measurements. The measurements of cutaneous temperature and the index of microcirculation were performed on the distal phalanx of the third finger of the right hand. Occlusion tests were performed with water baths at 25 and 42 °C and a tonometer cuff with a pressure of 200-220 mmHg for 3 min on the upper arm.

The results of experimental studies are presented and interpreted. These data indicate a violation of the blood supply regulation in the form of a pronounced tendency towards microvascular vasoconstriction in the fingers. Thus, the response displaying a tendency toward angiospasm among patients in the rheumatological diseases profile group was observed mainly in the most severe cases (49 % of this group). The prospects of the developed diagnostic method of microcirculatory disorders in rheumatic diseases are evaluated. Thus, cutaneous blood microcirculation and temperature measurements performed together can help in diagnosis of the functional state of peripheral vessels both in a healthy state and when expressing pathology.

This paper describes limit possibilities of modern cooled thermal imaging cameras as a tool for estimation of blood flow oscillations at the surface of living body. Skin temperature oscillations, as we assumed, are a consequence of the blood flow oscillations. We considered the temperature sensitivity 0.01-0.02 °C as a typical for the most of modern cooled long wave thermal imaging cameras. Fourier filter used to investigate the temperature signal separately within endothelial, neurogenic, myogenic, respiratory and cardiac frequency ranges. The level of temporal noise has been estimated during measurements of no living body with stabilized temperature ~ 24°C. The level of temperature oscillations has been calculated for the group of healthy subjects within each frequency range. Thus, we were able to determine signal-to-noise ratio within frequency band [0.001, 1] Hz. As a result, we determine that skin temperature oscillations measured by thermal imaging camera with sensitivity 0.02°C have the upper frequency limit ~ 0.2 Hz. In other words, within the respiratory and cardiac frequency ranges of blood flow oscillations the noise level exceeds signal one, and temperature measurements at the skin surface are practically useless. The endothelial, neurogenic and myogenic components of the temperature oscillations contain ~98% of the total spectral power of the signal. We have plot the empirical extrapolated curve of sensitivity of thermal imaging camera vs. frequency of the temperature oscillations. The data analysis shows that measurements of skin temperature oscillations within respiratory and cardiac ranges require the temperature sensitivity at least ~ 0.01°C and 0.001°C, respectively.

Fluorescence spectra and fluorescence induction curves of the leaves of two plant species in dependence on chlorophyll content were studied. Red oak (Quercus rubra L.) leaves upon the autumn chlorophyll degradation, as well as wheat leaves (Triticum aestivum L.) at various stages of ontogenesis showed linear dependence between the ratio ω = F740 / F685 (the ratio of the maximum values of fluorescence at respective wavelengths) and chlorophyll content. In both cases, parameter F_v / F_m (the relative value of the variable fluorescence) remained almost unchanged up to significant reduction of chlorophyll content, indicating on maintaining the high photochemical activity of photosystem 2.

Detection of phototropic organisms in their natural habitat using optical instruments operating under water is urgently needed for many tasks of ecological monitoring. While fluorescence methods are widely applied nowadays to detect and characterize phytoplankton communities, the techniques for detection and recognition of anoxygenic phototrophs are considered challenging. Differentiation of the forms of anoxygenic green sulfur bacteria in natural water using spectral techniques remains problematic. Green sulfur bacteria could be found in two forms, green-colored (containing BChl d in pigment compound) and brown-colored (containing BChl e), have the special ecological niche in such reservoirs. Separate determination of these microorganisms by spectral methods is complicated because of similarity of spectral characteristics of their pigments. We describe the novel technique of quantification of two forms of green sulfur bacteria directly in water using bacteriochlorophyll fluorescence without pigment extraction. This technique is noninvasive and could be applied in remote mode in the water bodies with restricted water circulation to determine simultaneously concentrations of two forms of green sulfur bacteria in their natural habitat.

We analyze the results received from two expeditions performed in August-September 2013, August-September 2014 and February 2015 in the Kandalaksha Bay of the White Sea. Depth profiles of hydrological characteristics and optical properties of water were recorded for five marine lakes being on different stages of isolation from the White Sea. Those relic lakes demonstrate a tendency to meromixis and are characterized by apparent stratification of the water bodies from the brackish top layer to the bottom salt water. Maximal concentrations of anoxygenic phototrophs (green sulfur bacteria) were found at depths close to the redox interface in all the studied lakes. To discriminate differently pigmented groups of microorganisms the fluorescence emission spectra of bacteriochlorophylls from the living cells were used. We puzzle out the data on light spectrum propagation through the water body in each lake using optical properties of water (attenuation spectra) in the UV, visible and NIR ranges, as well as direct measurements of the total irradiances at various depths. The changes in optical characteristics of water in the stratified reservoirs due to cromophoric dissolved organic matter (CDOM) and microbial pigments affect the light intensity and its spectral distribution at each water layer thus influencing the living conditions for differently pigmented phototrophic microorganisms and determining the composition of microbial community.

Hydrophobic components of cromophoric dissolved organic matter (CDOM) extracted from water samples and sediments taken in several relic basins located on Karelian shoreline of the White Sea were analyzed using spectroscopic techniques. Those water reservoirs exist at various stages of isolation from the White Sea and represent complex stratified systems of fresh and marine water layers not completely mixing trough the year. Basins separating from the White Sea are the unique natural objects for investigations of properties CDOM, its transformation in the process of turning the marine ecosystem into freshwater environment. CDOM occurring in all types of natural water represents a significant reservoir of organic carbon and plays a key role in the carbon cycle on the Earth. However, aquatic CDOM and nonliving organic matter in sediments from relic separating basins still have not been studied. The target of this work was to study absorption and fluorescence spectra of hydrophobic components of aquatic CDOM from different water depth and sediments in several separated basins of the Kandalaksha Gulf of the White Sea located near the N.A. Pertsov White Sea Biological Station.

The important advantage of diffuse optical tomography (DOT) is the possibility of tissue functional diagnosis. However the possibility implements if only we separately reconstruct the spatial distributions of optical parameters, specifically the absorption and scattering coefficients. We have recently demonstrated that time-domain DOT based on the perturbation model by Lyubimov is capable of reconstructing absorbing inhomogeneities in tissue with a DOT high spatial resolution (better than 3 mm at a depth of 4 cm). This paper continues our research and focuses on the reconstruction of scattering inhomogeneities. We consider the flat layer transmission geometry which is traditional for optical mammography, and use diffusion approximation to derive analytical expressions for weight functions responsible for the reconstruction of scattering inhomogeneities. To confirm that our calculations are correct we perform a numerical experiment where we reconstruct a rectangular scattering object 10×8 cm in size with 4 circular scattering macroinhomogeneities 4 mm in diameter each, and a randomly inhomogeneous scattering structure. The inverse DOT problem is solved with a multiplicative algebraic reconstruction technique where interim iterations are processed through total variation norm minimization. The results suggest that our DOT method reliably resolves the scattering macroinhomogeneities of mentioned size against a randomly inhomogeneous structure.

Detection of blood vessels within light-scattering tissues involves detection of subtle shadows as blood absorbs light. These shadows are diffuse but measurable by a set of source-detector pairs in a spatial array of sources and detectors on the tissue surface. The measured shadows can reconstruct the internal position(s) of blood vessels.

The tomographic method involves a set of N_s sources and N_d detectors such that N_sd = N_s x N_d source-detector pairs produce N_sd measurements, each interrogating the tissue with a unique perspective, i.e., a unique region of sensitivity to voxels within the tissue.

This tutorial report describes the reconstruction of the image of a blood vessel within a soft tissue based on such source-detector measurements, by solving a matrix equation using Tikhonov regularization. This is not a novel contribution, but rather a simple introduction to a well-known method, demonstrating its use in mapping blood perfusion.

In this study, the refractive index of hemoglobin was measured at different temperatures within a physiological range and above that is characteristic to light-blood interaction at laser therapy. Measurements were carried out using the multi-wavelength Abbe refractometer (Atago, Japan). The refractive index was measured at two NIR wavelengths of 930 nm and 1100 nm. Samples of hemoglobin solutions with concentration of 80, 120 and 160 g/l were investigated. The temperature was varied between 25 and 55 °C. It was shown that the dependence of the refractive index of hemoglobin is nonlinear with temperature, which may be associated with changes in molecular structure of hemoglobin.

Cyanobacteria bloom is a great ecological problem of Curonian Lagoon and Baltic Sea. The development of novel methods for the on-line control of cyanobacteria concentration and, moreover, for prediction of bloom spreading is of interest for monitoring the state of ecosystem. Here, we report the results of the joint application of hyperspectral measurements and remote sensing of Curonian Lagoon in July 2015 aimed at the assessment of cyanobacteria communities. We show that hyperspectral data allow on-line detection and qualitative estimation of cyanobacteria concentration, while the remote sensing data indicate the possibility of cyanobacteria bloom detection using the spectral features of upwelling irradiation.

We report the results on in ovo application of developed Laser Doppler Anemometer (LDA) device. The chorioallantoic membrane (CAM) of 9-13 days chicken embryos was used as a biological model that allows an easy access to both arterial and venous vessels of different size. The key point of our study was to find out how the periodic and aperiodic pulsations of blood flow (which are inevitable in living organism) will affect the LDA functions and measuring capability. Specifically, we (i) developed the technique to extract and refine the pulse rhythm from the signal received from a vessel, and (ii) analyzed the changes in power spectra of LDA signal that are caused by heart beating and considerably complicate the reliable measurement of Doppler shift. Our main conclusion is that the algorithm of LDA data processing need to be improved, and this possibly can be done by counting the information on current phase of cardiac cycle.

In this article we have applied liquid-liquid extraction (LLE) as a sample preparation technique for detection of sulfadimethoxine (one of sulfonamide drugs) in urine using surface-enhanced Raman spectroscopy (SERS). SERS substrate based on silver nanoparticles has been prepared by citrate reduction of silver nitrate. Obtained calibration curve (SERS intensity vs. sulfadimethoxine concentration) has been used for detection of sulfadimethoxine in human urine samples artificially contaminated by sulfadimethoxine. Three different solvents (ethyl acetate, diethyl ether, chloroform) have been used for LLE performance tests. Chloroform being found as the most effective one based on calculation of recoveries after SERS measurements. Thus we would like to propose fast (less than 20 minutes), simple and sensitive (detection limit up to 1 μg/ml) test for detecting sulfa drugs in urine using a combination of SERS with LLE with sample volume as low as 100 μL. Such test can be applied for evaluation of the degree of drug extraction from human body and half-life of such drug applied in the course of therapeutic treatments of certain diseases.

This study examines the effect of blood absorption on the endogenous fluorescence signal intensity of biological tissues. Experimental studies were conducted to identify these effects. To register the fluorescence intensity, the fluorescence spectroscopy method was employed. The intensity of the blood flow was measured by laser Doppler flowmetry.

We proposed one possible implementation of the Monte Carlo method for the theoretical analysis of the effect of blood on the fluorescence signals. The simulation is constructed as a four-layer skin optical model based on the known optical parameters of the skin with different levels of blood supply. With the help of the simulation, we demonstrate how the level of blood supply can affect the appearance of the fluorescence spectra.

In addition, to describe the properties of biological tissue, which may affect the fluorescence spectra, we turned to the method of diffuse reflectance spectroscopy (DRS). Using the spectral data provided by the DRS, the tissue attenuation effect can be extracted and used to correct the fluorescence spectra.

The work is devoted to the study of the interaction of heavy metals with bovine serum albumin (BSA) and human serum albumin (HSA), by quenching of the intrinsic fluorescence of proteins and fluorescent probe pyrene by heavy metal ions. Sulfates of copper and zinc (CuSO4, ZnSO4) were taken as the metal salts. The value of the Stern-Volmer constants of quenching of intrinsic fluorescence of proteins and fluorescence probe pyrene reduced from Cu (II) to the Zn (II). It was experimentally found that the copper ions have a greater ability to fluorescence quenching, which is probably associated with the greater availability of protein chromophore groups to copper ions and with adsorbed fluorescent probe pyrene in the protein globule.

The processes of interaction of fluorescent probes: eosin and erythrosine with human serum albumin (HSA) were studied by the methods of absorption and fluorescence spectroscopy. Extinction coefficients of probes were determined. Critical transfer radius and the energy transfer efficiency were defined by fluorescence quenching of HSA. Analysis of the excitation spectra of HSA revealed that the energy transfer process is carried out mainly between tryptophanyl and probes.

Control methods of temperature fields inside a tissue during laser photothermolysis are an important point to develop biomedical applications of thermal destructions of cancer. One of the most promising approaches to measure and to control of temperature is the application of luminescence nanothermometers such as CuInS₂ nanoparticles. Temperature measurement can be carried out by determination of the maximum of the luminescence band. Thus, we have investigated the influence of exposure time and temperature on the position of the maximum of the luminescence band of CuInS₂ nanoparticles.

Manuscript is devoted to the comparison of CdSe/ZnS and CuInS₂/ZnS quantum dots thermosensitivity in the view of their applications as nanothermometers. It was found the luminescence spectrum of CuInS₂/ZnS quantum dots consists of two components, which are described by Gauss type functions and connected with different types of defects into nanoparticles. The heat treatments provide different effects such as spectral shifts, FWHM and amplitude for these too components. CdSe/ZnS nanoparticles spectra shifted to the red region; the average speed of spectrum shift is 0.065 nm per degree.

Among all plasma proteins human serum albumin (HSA) is the most studied one as it is the main transport protein and can bind a wide variety of ligands especially fatty acids (FAs). The concentration of FAs bound to HSA in human blood plasma differs by three times under abnormal conditions (fasting, physical exercises or in case of social important diseases). In the present study a surfactant sodium dodecyl sulfate (SDS) was used to simulate FAs binding to HSA. It was shown that the increase of Tyr fluorescence of human blood plasma due to SDS addition can be completely explained by HSA-SDS complex formation. Binding parameters of SDS-HSA complex (average number of sites and apparent constant of complex formation) were determined from titration curves based on tyrosine (Tyr) fluorescence.

We report an efficient synthesis Cd-free CuInS₂/ZnS (CIS/ZnS) quantum dots (QDs) using low toxic precursors and investigation of their optical properties. The nanocrystals have been obtained via reaction between the acetate salts of the corresponding metals and elemental sulfur in the presence of dodecanethiol in octadecene media at 220°C. Influence of various experimental variables, including temperature, time, ratio of Cu and In precursors were investigated. Thus, it was shown that the photoluminescence (PL) emission wavelength can be tuned by conveniently changing the stoichiometric ratio of the components. The plain CIS nanocrystals did show PL emission but with quite low PL quantum yield (QY). In order to increase the QY of QD luminescence by compensation of the surface defects of QDs cores, the process of covering with ZnS shells was done. During shelling process, increasing of QY and blue shift of emission maximum were detected.

Fluorimetry of eye is a perspective technique for research and diagnostics in оphthalmology. It is connected to the structural and functional characteristics of eye that is, actually, the optical system allowing transferring the radiation both for excitation and for registration of fluorescence in different eye’s compartments: cornea, lens, vitreous body, and fundus of the eye. At present, different models of ophthalmologic fluorophotometers for the analysis of eye fluorescence as well as more advanced models – scanning fluorophotometers - are offered. Assessment of corneal status in persons wearing contact lenses or in patients with pathological changes (i.e. diabetes mellitus) would give us an opportunity to identify the initial manifestations of corneal pathology at the pre-symptomatic phase. In this paper, we present data on the compact spectrofluorimeter with UV LEDs-induced excitation as well as the method for assessing hypoxic alterations in the eye limb zone caused by contact lenses wearing. We demonstrate dependence of autofluorescence spectra on the contact lenses types and duration of their permanent wearing.

Silanization is a convenient route to provide water-solubility to the quantum dots (QDs) with different structure. Green, orange and red emitting CdSe-based QDs were synthesized by varying of number and material of wider-band gap shells and fluorescent properties of QDs were characterized before and after silanization. It was shown that structure of the QD influences on the quantum yield of the silanized QDs: the better CdSe core is protected with wider-band gap semiconductor shells, the more fluorescence properties remain after silica coated QD possess. Hence silica coated QDs have a great perspectives for the multiplex analysis.

In this article the results of solution of two-parametrical inverse problems of laser Raman spectroscopy of identification and determination of concentration of DNA nitrogenous bases in two-component solutions are presented. Elaboration of methods of control of reactions with DNA strands in remote real-time mode is necessary for solution of one of the basic problems of creation of biocomputers – increase of reliability of molecular DNA-computations. The comparative analysis of two used methods of solution of stated problems has demonstrated convincing advantages of technique of artificial neural networks. Use of artificial neural networks allowed to reach the accuracy of determination of concentration of each base in two-component solutions 0.2-0.3 g/l.

A new method for the formation of composite nanomaterials based on multi-walled and single-walled carbon nanotubes (CNT) on a silicon substrate has been developed. Formation is carried out by ultrasound coating of a silicon substrate by homogenous dispersion of CNTs in the albumin matrix and further irradiation with the continuous laser beam with a wavelength of 810 nm and power of 5.5 watts. The high electrical conductivity of CNTs provides its structuring under the influence of the laser radiation electric field. The result is a scaffold that provides high mechanical strength of nanocomposite material (250 MPa). For in vitro studies of materials biocompatibility a method of cell growth microscopic analysis was developed. Human embryonic fibroblasts (EPP) were used as biological cells. Investigation of the interaction between nanocomposite material and cells was carried out by optical and atomic force microscopy depending on the time of cells incubation. The study showed that after 3 hours incubation EPP were fixed on the substrate surface, avoiding the surface of the composite material. However, after 24 hours of incubation EPP fix on the sample surface and then begin to grow and divide. After 72 hours of incubation, the cells completely fill the sample surface of nanocomposite material. Thus, a nanocomposite material based on CNTs in albumin matrix does not inhibit cell growth on its surface, and favours their growth. The nanocomposite material can be used for creating soft tissue implants

Gold nanoshells are promising nanoparticles for biomedical applications such as biosensing, photothermal therapy, and surface enhanced Raman scattering. However, existing synthesis protocols produce polydisperse samples with extinction plasmonic spectrum much broader than that predicted by electromagnetic Mie simulations. Here we report on improved synthesis of gold nanoshells using monodisperse silica cores with very narrow size distributions of separated samples. As a result we were able to fabricate high quality silica/gold nanoshells with very narrow plasmon resonance peak, which is in good agreement with Mie calculations based on polydisperse TEM models. TEM images revealed a presence of dimers and trimers in as-prepared nonseparated samples. We performed extensive finite difference time-domain (FDTD) simulations to show that the plasmonic response of aggregated nanoshells results in enhanced extinction across NIR spectral band and in a minor broadening of the main plasmonic peak. To summarize, the improved synthetic technology produces high quality monodisperse silica/gold nanoshells which optical properties are in excellent agreement with electromagnetic simulations based on TEM size distributions.

With the purpose to develop bright non-toxic luminescent label for theranostic application we have studied complexation of lanthanide dipicolinates (2,6-pyridinedicarboxylates) by sodium alginate and effect of thermal exposure of synthesized micro-capsules on their luminescent properties. Synthesized micro-capsules are stable in acidic medium but dissolve at pH ~ 4 due to transformation of cationic europium dipicolinate complex to anionic. Luminescence studies have shown that emission spectra of europium(III)-alginate complexes (both chloride and dipicolinate) contain two intensive bands characteristic to Eu³⁺ ion (⁵D₀ → ⁷F₁ (590 nm) and ⁵D₀ → ⁷F₁ (612 nm)). We have also found that at 160ºC europium(III)- alginate micro-capsules decompose to black, soot-like substance, therefore, their thermal treatment must be performed in closed environment (i.e., sealed ampoules).

Application of different methods for formation of microcontainers containing iodine is proposed in this paper. Two types of microcontainers: microemulsions and microparticles have been investigated, conditions and methods for obtaining microcontainers were optimized.

Microparticles were formed by layer-by-layer method with cores of calcium carbonate (CaCO₃) as templates. Incorporation of complexes of iodine with polymers (chitosan, starch, polyvinyl alcohol) into core, shell and hollow capsules was investigated and loadings of microparticles with iodine were estimated. It was found that the complex of iodine with chitosan adsorbed at CaCO₃ core is the most stable under physiological conditions and its value of loading can be 450 μg of I2 per 1 g of CaCO₃. Moreover, chitosan was chosen as a ligand because of its biocompatibility and biodegradability as well as very low toxicity while its complex with iodine is very stable. A small amount of microparticles containing a iodine–chitosan complex can be used for prolonged release of iodine in the human body since iodine daily intake for adults is around 100 μg.

"Oil-in-water" emulsions were prepared by ultrasonication of iodinated oils (sunflower and linseed) with sodium laurilsulfate (SLS) as surfactant solution. At optimal conditions, the homogenous emulsions remained stable for weeks, with total content of iodine in such emulsion being up to 1% (w/w). The oil:SLS ratio was equal to 1:10 (w/w), optimal duration and power of ultrasound exposure were 1.5 min and 7 W, correspondingly. Favorable application of iodized linseed oil for emulsion preparation with suitable oil microdroplets size was proved.

A construction of a low-coherence fiber-optic Fabry-Pérot interferometer using a thin ZnO layer as a reflective surfaces was proposed and examined. In the investigated setup, the ZnO layer of thickness 200 nm were deposited on the face of the standard telecommunication single-mode optical fiber (SMF-28). Measurements of interference signal were performed for the interferometer working in the transmission and reflective mode, as well. The measurements were performed for two wavelength (1300 nm and 1550 nm) for various length of the air cavity. The optimal parameters of the Fabry-Pérot cavity was chosen for achieving the best visibility of the interference signal in the both modes.

The laser ablation method was implemented for synthesis of ruby nanoparticles. Nanoparticles were obtained by nanosecond ablation of bulk ruby crystal in 10% ethanol water solution. The nanoparticles enable water colloid stability and exhibit narrow photoluminescent line at 694 nm when pumped at blue-green spectral range. The ruby nanoparticles were characterized by SEM and Z-sizer.

Gold nanoparticles (GNPs) have attracted significant interest as a novel platform for various applications to nanobiotechnology and biomedicine. The conjugates of GNPs with antibiotics and antibodies were also used for selective photothermal killing of protozoa and bacteria. Also the conjugates of some antibiotics with GNPs decreased the number of bacterial growing cells. In this work was made the procedure optimization for conjugation of cefotaxime (a third-generation cephalosporin antibiotic) with GNPs (15 nm) and we examined the antimicrobial properties of this conjugate to bacteria culture of E. coli K-12. Addition of cefotaxime solution to colloidal gold does not change their color and extinction spectrum. For physiologically active concentration of cefotaxime (3 μg/mL), it was shown that the optimum pH for the conjugation was more than 9.5. A partial aggregation of the GNPs in saline medium was observed at pH 6.5-7.5. The optimum concentration of K₂CO₃ for conjugation cefotaxime with GNPs-15 was 5 mM. The optimum concentration of cefotaxime was at 0.36 μg/mL. We found the inhibition of the growth of E. coli K12 upon application cefotaxime-GNP conjugates.

Photonic crystal fibers (PCFs) with a hollow core are one of the most promising solid support of fiber-optic sensors. The main advantages of PCF as sensor elements in clinical analysis are minimization of optical interactions from the sample and the ability to analyze small volume of samples. At the same time, low sorption capacity of glass which is the basic material for the fabrication of the PCF, limits their use in the development of biosensors. Modification of the inner surface of the PCF can be the solution of the problem.

In this work the synthesis of self-assembled films of polyaniline (PANI) on the inner surface of the PCFs was carried out. The modified PCFs were studied by spectroscopy and electron microscopy. It was found that the covering of the inner surface of the PCFs with PANI leads to a shift of the local maximums of the transmission spectrum PCFs up to 25 nm. These makes possible to design the method of varying of photonic bandgaps location.

New SERS-active materials were obtained by preparation of alumina with embedded silver nanoparticles and their application both as sorbents for pre-concentration and SERS platforms was studied. The influence of ionic strength on Ag NPs size, absorption spectra and SERS signal was investigated. Synthesized materials were examined by Raman spectroscopy, scanning electron microscopy, and UV-visible spectroscopy. The optimal conditions for SERSmeasurements were chosen. Synthesized materials were applied for pre-concentration of model analytes (Rhodamine 6G, folic acid and pyrene) and their SERS detection directly within the sorbent. It was shown that the recovery of analytes could be improved by alumina modification. The combination of surface-enhanced Raman spectroscopy with preconcentration is a promising instrument for analytical applications.

Currently, nanotechnologies are widely used in science and industry. It is known that the application of drug delivery nanostructured carriers for biomedicine is one of the promising areas of nanotechnology. Nanostructured carriers can be used in the diagnosis process for detecting a neoplastic tumor cells in peripheral blood, for contrast enhancement on magnetic resonance imaging (MRI), as well as for targeted drug delivery to tumor tissues. Agents for the targeted delivery (nanoparticles, liposomes, microcapsules, and etc) can affect the healthy tissues and organs, cause side effects and have a toxic effect. Therefore, it necessary to study the morphological changes that occur not only in the "target", such as a tumor, but also the internal organs, taking place under the influence of both the agents for targeted drug delivery and physical impact induced remote controlled drug release. Thus , the aim of our work is selection of the most promising agents for targeted drug delivery to tumor and contrast agents for in vivo visualization of tumor tissue boundaries , as well as their impact on the organs and tissues as results of nanostructured object biodistribution.

Microcapsules with and without magnetite nanoparticles incorporated in the polyelectrolyte shell were prepared. The effect of external electric field on the nanocomposite polyelectrolyte microcapsules containing magnetite nanoparticles in the shell was studied in this work as a function of the electric field strength. Effect of electric fields on polyelectrolyte microcapsules and the control over integrity of polyelectrolyte microcapsules with and without inorganic nanoparticles by constant electric field has been investigated. Beads effect, aggregation and deformations of nanocomposite microcapsule shell in response to electric field were observed by confocal laser scanning microscopy (CLSM). Thus, a new approach for effect on the nanocomposite microcapsule, including opening microcapsule shell by an electric field, was demonstrated. These results can be used for creation of new systems for drug delivery systems with controllable release by external electric field.

The process of formation of Langmuir monolayers of quantum dots at the different subphase temperatures was studied by means of compression isotherm, Brewster angle microscopy and transmission electron microscopy. The increasing of the maximum surface pressure from 32 to 44 mN/m takes place with decreasing the temperature from 34 to 11°C. This is due to a decrease in the rate of dissolution of surfactant molecules in water. The increasing of a filling degree of monolayer by the quantum dots and increasing of it uniformity in thickness takes place in this temperature range. The area of bilayer and multilayer film of quantum dots decreasing and the area of quantum dots monolayer is increasing. This change explained by the difference in the phase condition of oleic acid molecules, which stabilized quantum dots.

The formation of a monolayer and its structure depend on many factors. One of the least studied factors is the influence of the electric field. In this regard, the purpose of this study is to investigate the influence of the direction and magnitude of the electric field on the properties of monolayer, formed on the surface of water. The experiments have revealed: the electric field exerts a significant influence on the formation of monolayers, in particular, during liquid phase formation. The second part of the isotherm (corresponding liquid phase) were significantly stretched. We explain the liquid phase extension by the fact of the charge increasing (and change pH) of the surface region. To confirm this assumption also we made computer modelling of process monolayer formation.

Research results on the chemical composition and surface morphological characteristics of zirconium products after machining and treatment with high-frequency currents are described. It was established that at the temperature range from 600 to 1200 °C and duration of heat treatment from 30 to 300 seconds oxide coatings consisting of nano-grains are formed.

The study focuses on high-performance combined electro-spark alloying of titanium and titanium alloy (VT1-0, VT16) surface and porous matrix structure oxidation. The metal-oxide coatings morphology is the result of melt drop transfer, heat treatment, and oxidation. The study establishes the influence of technological regimes of alloying and oxidation on morphological heterogeneity of biocompatible layered metal-oxide system Ti-Ta-(Ti,Ta)_xO_y. It was found that during electro-spark alloying the concentration of tantalum on the titanium surface ranges from 0.1 to 3.2 at.%. Morphology of the deposited splats is represented by uniformly grown crystals of titanium and tantalum oxides, which increase from nano- to submicron size.

This report devoted to presenting results of development and implementation of a short course (4 hours) entitled "Introduction to Nanotechnology" that was specially designed for familiarizing high school students with nanomaterials and nanotechnology. The course contains introduction to nanotechnology, essential definitions, short overview of history, descriptions for various examples of nanomaterials and their classifications, performing demonstration experiments. All these parts of the course are briefly analyzed from pedagogical effectiveness point of view. Finally, results of course testing, problems and perspectives of nano-oriented education at high school are also discussed shortly.

The technology of production of matrix photoreceivers based on carbon nanotubes (CNTs) consisting of 16 sensitive elements was developed. Working wavelength range, performance and sensitivity were studied.

The results of the study of morphological and biophysical parameters of the cell membrane of live lymphocytes in patients with insulin-dependent and non-insulin dependent diabetes mellitus and healthy donors using atomic force microscopy have been presented. It is found that lymphocytes from patients with diabetes are characterized by a decrease in volume and cell surface roughness compared to normal lymphocytes. An increase in the Young's modulus of lymphocytes in patients with diabetes more than 3 times compared to normal rates has been shown. Increased stiffening of lymphocyte cytolemma in patients with non-insulin dependent diabetes mellitus leads to a decrease in its adhesive properties, unlike lymphocytes in patients with insulin-dependent diabetes mellitus.

This work presents the results of studying the mitochondrial membrane potential, intracellular ROS, peculiarities of the cell cycle of cancer cells HCT-116 and the normal line of CHO cells when exposed to the red LED light with a wavelength range of 0.620-0.680 μm. A dose-dependent increase in mitochondrial membrane potential and intracellular ROS concentration in cancer cells HCT-116 was established. In normal CHO cell line a dose-dependent reduction of mitochondrial membrane potential and dose-dependent increase in intracellular ROS occur. It has been shown that the sensitivity of the studied cell lines to the red light depends on the stage of the cell cycle.

Shadow Scanning Lens-free Microscopy (SSLM) is a possible method for optical imaging that can potentially achieve high spatial resolution. At present work we discuss the SSLM and analyse the resolution limit conditioned by the light scattering from the edge scanning imaging system that uses a shadow from moving knife edge or wire to collect the sets of tomographic projection data of two-dimensional objects. The results of numerical estimation of the SSLM resolution for reconstruction of 2D object image are presented. The experimental setup of SSLM with wire scanning element was developed. The developed device works in a UV band range and shows the spatial resolution about 90 nm.

Recently proposed in vivo label-free optical coherence angiography techniques based on phase and amplitude speckle variability often require additional signal pre- and post processing operations to enhance vessel-contrast. We observe here 1) contrast enhancement by optimizing the signal normalization/weighing before processing; 2) algorithm based on Kasai estimator for phase compensation between processed A-scans to reduce masking role of motion artifacts; and 3) image projection through the imaging depth for en face plotting. We demonstrate the efficiency of proposed additional algorithms as for the microcirculation imaging of hamsters cheek in vivo as for the preliminary microcirculation imaging of patients after radiotherapy. This technical framework complete in details our recent publications on M-Mode like OCT algorithms and its implementation.

We propose μPIV-based technique for quantitative assessment of blood flow redistribution in microcirculatory networks. Our approach is based on per-segment averaging of measured quantities so we can avoid most of problems that are typical for point-wise measurements. The key point of our technique is the digital processing algorithms of recorded data that include: capillary network axial line construction; interrogation regions centering; blood flow velocity local estimate using PIV approach; blood flow velocity calculation by means of averaging over entire vessel segment; the calculation of blood volume flow rate map. We illustrate the application of developed technique with in vivo measurements and blood flow velocity map reconstruction for chorioallantoic membrane (CAM) of chicken embryo, in which the local vascular occlusion was produced using continuous wave laser light irradiation..

Creatine kinase is a key enzyme of energy metabolism in the brain. There are known cytoplasmic and mitochondrial creatine kinase isoenzymes. Mitochondrial creatine kinase exists as a mixture of two oligomeric forms – dimer and octamer. The aim of investigation was to study catalytic properties of cytoplasmic and mitochondrial creatine kinase and using of the method of empirical dependences for the possible prediction of the activity of these enzymes in cerebral ischemia. Ischemia was revealed to be accompanied with the changes of the activity of creatine kinase isoenzymes and oligomeric state of mitochondrial isoform. There were made the models of multiple regression that permit to study the activity of creatine kinase system in cerebral ischemia using a calculating method. Therefore, the mathematical method of empirical dependences can be applied for estimation and prediction of the functional state of the brain by the activity of creatine kinase isoenzymes in cerebral ischemia.

Diffraction phase microscopy (DPM) provides the possibility of high-resolution quantitative phase imaging, based on equipment of an optical microscope with a special module working in a common-path off-axis configuration. As an optical microscopy technique, DPM has a limited focus depth, which is the smaller the higher is the objective's numerical aperture. In this paper we present the results of experimental investigation of numerical focusing with the angular spectrum method in DPM.

In this paper, we present a novel simple technique of Fourier-transform holographic microscopy (FTHM). Simplicity of the scheme, possibility to use a small image sensor and provide compensation of aberration, enable one to construct inexpensive holographic microscopes. We experimentally compare FTHM with in-line holographic microscopy. In this paper, we present experimental scheme of FTHM, description of used algorithms and experimental results for an amplitude test object and biological samples (blood smears).

WAG/Rij rats are well known genetic model of absence epilepsy, which is traditionally considered as a nonconvulsive generalised epilepsy of unknown aetiology. In current study the effect of (R)-(+)-WIN 55,212-2 (cannabis agonist) injection on the coupling between different parts of cortex was studied on 27 male 8 month old rats using local field potentials. Recently developed non-linear adapted Granger causality approach was used as a primary method.

It was shown that first 2 hours after the injection the coupling between most channel pairs rises in comparison with the spontaneous activity, whilst long after the injection (2-6 hours) it drops down. The coupling increase corresponds to the mentioned before treatment effect, when the number and the longitude of seizures significantly decreases. However the subsequent decrease of the coupling in the cortex is accompanied by the dramatic increase of the longitude and the number of seizures. This assumes the hypothesis that a relatively higher coupling in the cortical network can prevent the seizure propagation and generalisation.

The etalon-photometric method for quantitative estimation of physical density of pathological entities is considered. The method consists in using etalon during the registration and estimation of photometric characteristics of objects. The algorithm for estimating of physical density at X-ray images is offered.

In recent decades modelling studies on cortical spreading depression (CSD) and migraine waves successfully contributed to formation of modern view on these fundamental phenomena of brain physiology. However, due to the extreme complexity of object under study (brain cortex) and the diversity of involved physiological pathways, the development of new mathematical models of CSD is still a very relevant and challenging research problem.

In our study we follow the functional modelling approach aimed to map the action of known physiological pathways to the specific nonlinear mechanisms that govern formation and evolution of CSD wave patterns. Specifically, we address the role of cerebral blood flow (CBF) redistribution that is caused by excessive neuronal activity by means of neurovascular coupling and mediates a spatial pattern of oxygen and glucose delivery. This in turn changes the local metabolic status of neural tissue. To build the model we simplify the web of known cell-to-cell interactions within a neurovascular unit by selecting the most relevant ones, such as local neuron-induced elevation of extracellular potassium concentration and biphasic response of arteriole radius. We propose the lumped description of distance-dependent hemodynamic coupling that fits the most recent experimental findings.

In the present work we discuss the features of the DNA replication kinetics at the case of multiplicity of simultaneously elongated DNA fragments. The interaction between replicated DNA fragments is carried out by free protons that appears at the every nucleotide attachment at the free end of elongated DNA fragment. So there is feedback between free protons concentration and DNA-polymerase activity that appears as elongation rate dependence. We develop the numerical model based on a cellular automaton, which can simulate the elongation stage (growth of DNA strands) for DNA elongation process with conditions pointed above and we study the possibility of the DNA polymerases movement synchronization. The results obtained numerically can be useful for DNA polymerase movement detection and visualization of the elongation process in the case of massive DNA replication, eg, under PCR condition or for DNA "sequencing by synthesis" sequencing devices evaluation.

In this paper we suggest the new approach of powerful sub-THz signal generation based on intense electron beams containing oscillating virtual cathode. Suggested compact microwave source complies with a number of biomedical applications such as imaging, preventive healthcare, etc. In this work we discuss the results of numerical simulation and optimization of the novel device called “nanovircator” that have been carried out. The results of the numerical study show the possibility of “nanovircator” operation at 0.1-0.4 THz frequency range.

The data transmission method using the highest harmonics of semiconductor superlattice-based microwave generator has been proposed for biomedical applications. Semiconductor superlattice operated in charge domain formation regime is characterized by the rich high-harmonics power spectrum. The numerical modeling of modulation and detection of the THz range signals using the highest harmonics of the fundamental frequency of the superlattice-based generator was carried out. We have shown effectiveness of the proposed method and discussed the possible applications.

Generalized synchronization in complex networks with chaotic dynamical systems being in their nodes has been studied. The synchronous regime is shown to be detected by the sign-change of the second positive Lyapunov exponent of the network or by the nearest neighbor method. The same method is shown to be applied for the detection of the synchronous regime between the different fields of epileptic brain.

Absence seizures are known to be highly non-linear large amplitude oscillations with a well pronounced main time scale. Whilst the appearance of the main frequency is usually considered as a transition from noisy complex dynamics of baseline EEG to more regular absence activity, the dynamical properties of this type of epileptiformic activity in genetic absence models was not studied precisely.

Here, the estimation of the largest Lyapunov exponent from intracranial EEGs of 10 WAG/Rij rats (genetic model of absence epilepsy) was performed. Fragments of 10 seizures and 10 episodes of on-going EEG each of 4 s length were used for each animal, 3 cortical and 2 thalamic channels were analysed. The method adapted for short noisy data was implemented. The positive values of the largest Lyapunov exponent were found as for baseline as for spike wave discharges (SWDs), with values for SWDs being significantly less than for on-going activity.

Current findings may indicate that SWD is a chaotic process with a well pronounced main timescale rather than a periodic regime. Also, the absence activity was shown to be less chaotic than the baseline one.

In the paper we study the mechanisms of phase synchronization in the adaptive model network of Kuramoto oscillators and the neural network of brain by consideration of the integral characteristics of the observed networks signals. As the integral characteristics of the model network we consider the summary signal produced by the oscillators. Similar to the model situation we study the ECoG signal as the integral characteristic of neural network of the brain. We show that the establishment of the phase synchronization results in the increase of the peak, corresponding to synchronized oscillators, on the wavelet energy spectrum of the integral signals. The observed correlation between the phase relations of the elements and the integral characteristics of the whole network open the way to detect the size of synchronous clusters in the neural networks of the epileptic brain before and during seizure.

Assessment of pulse waves that recorded in the microvascular bed when the heart throwing blood appears to be the essential diagnostic method. The conventional non-invasive methods are mostly based on measurement of pulse wave velocity (PWV) which was proved to be the predictor of cardiovascular system state. Photoplethysmography (PPG) is a simple and low-cost optical technique that can be used to detect blood volume changes in the microvascular bed of tissue. Since many factors contribute to PWV formation, it shows considerable variability and sensitive to the current physiological state. Traditional mathematical methods that examine this variability in the frequency domain, such as Fourier analysis, not always the best choice since the non-stationary features of PWV signal. A relatively new, but already popular tool, Wavelet transform, allows multiresolution analysis in time-frequency domain of non-stationary signals. In our work we apply Wavelet Cross Spectrum (WCS) and Wavelet-Based Coherence (WBC) to reveal the similarities between two PWV time series recorded simultaneously from left and right arms. We find that the degree correlation and the time lag between these signals considerably depend on frequency range. On this basis, we hypothesize the systemic (neurogenic) origin of high-frequency (0.2 Hz) PWV variations.

In spite of growing body of experimental and theoretical results on blood flow (BF) patterns under the continuously sustained circulation, much less is known about BF dynamics under the exceptional, but still important cases of venous or arterial occlusion used in medical probes. Since these conditions finally lead to complete or nearly complete stop of red blood cells (RBC) motion, we term it as TTBF, being the Terminal Transients of Blood Flow. An extreme case of such transients is the ultimate extinction of BF after the stopping of heart contractions, during which it is governed by gravitation, some vascular-originated propulsion mechanisms, and, possibly, by RBC aggregation. Quite little is known about this process, while reports the detectable post-mortal motion of mice RBC during at least 2 hours. In our work we present the modeling study of TTBF patterns due to gravitational forces. We present the minimalistic model configuration of vasculature in order to simulate what happens immediately after the pumping of blood has been stopped. Our main findings are concerned to reversal of arterial BF, as well as to duration and non-monotonicity of transients.

Application of noninvasive optical coherent-domain methods and advanced data processing tools such as the wavelet-based multifractal formalism allows revealing effective markers of early stages of functional distortions in the dynamics of cerebral vessels. Based on experiments performed in rats we discuss a possibility to diagnose a hidden stage of the development of intracranial hemorrhage (ICH). We also consider responses of the cerebrovascular dynamics to a pharmacologically induced increase in the peripheral blood pressure. We report distinctions occurring at the levels of macro- and microcerebral circulation.

The detection of coupling presence and direction between cortical areas from the EEG is a popular approach in neuroscience. Granger causality method is promising for this task, since it allows to operate with short time series and to detect nonlinear coupling or coupling between nonlinear systems.

In this study EEG multichannel data from adolescent children, suffering from unilateral cerebral palsy were investigated. Signals, obtained in rest and during motor activity of affected and less affected hand, were analysed. The changes in inter-hemispheric and intra-hemispheric interactions were studied over time with an interval of two months. The obtained results of coupling were tested for significance using surrogate times series. In the present proceeding paper we report the data of one patient. The modified nonlinear Granger causality is indeed able to reveal couplings within the human brain.

The article is devoted to the research capabilities of mucociliary clearance in the nasal cavity and paranasal sinuses using modern techniques of digital video recording and processing. We describe the setup and software for this method and the results of our research. Using microscope and digital camera we can provide a good method to study mucociliary clearance and by usage of special software we able to measure some characteristic of nasal mucosae and its main function.

The polarization conversion of terahertz radiation by the periodic array of graphene nanoribbons located at the surface of a high-refractive-index dielectric substrate (terahertz prism) is studied theoretically. Giant polarization conversion at the plasmon resonance frequencies takes place without applying external DC magnetic field. It is shown that the total polarization conversion can be reached at the total internal reflection of THz wave from the periodic array of graphene nanoribbons even at room temperature.

Polarizing properties of molecular ensembles with different structures are investigated by numerical simulation. Carbon nanotubes with zigzag configuration and nucleobases are considered. By numerical simulation total polarizability is investigated for different structures of molecules ensembles. New semi-analytical procedure for calculation of total polarizability for ensembles with different configuration is offered and tested by its application to ensembles which contain single-wall carbon nanotubes and nucleobases.

The effect of increase in the uncertainty of local polarization states of laser light forward scattered by random media was studied in the experiments with phantom scatterers. At macroscopic level this effect is related to decay in the degree of polarization of scattered light in the course of transition from single to multiple scattering. Gelatin layers with embedded titania particles were used as the phantom scatterers. Features of distributions of local polarization states in various polarization coordinates were considered.

This study focuses on the analysis of the temperature-dependent dynamics of scatterers in aqueous solutions of gelatin with added scattering centers (submicron particles of titanium dioxide), whose characterized by high scattering efficiency, during the process of gelation. The technique of full field speckle-correlometry with a localized source of probing radiation and the spatial filtering of the speckle-modulated images of the medium surface was applied to investigate systems with different values of the volume fraction of scatterers. It was shown that the Arrhenius equations with significantly different values of the activation energy can describe the temperature dependencies of the correlation time of speckle intensity fluctuations for temperature ranges above and below the gelation characteristic temperature. Note that the correlation time of speckle intensity fluctuations is determined by the mobility of the scattering centers in the medium. This suggests the existence of transition between two different regimes of spatially limited diffusion of scattering centers in the probed medium under the condition of "sol-gel" transition. The estimated values of activation energy of spatially limited scatter diffusion in the studied systems at low temperatures correlate with the published values of the gelation activation energy for gelatin aqueous solutions.

Monte Carlo modeling of light transport in tissues with complex structure and dynamics using an original approach of speckle-correlometry based on ring-like apertures and localized source of probe light are presented. The "dynamic" long inclusions with different geometry and depth location in the "static" inhomogeneous layer imitated biotissue with different characteristics of microcirculation were chosen as a simulated medium. In the simulations, the refractive-index of "static" tissue – "dynamic" inclusion boundary is not match, thus the phenomenon of internal multiple reflection takes place. The backscattering coefficient of laser light scattered by the simulated medium evaluated as a ratio of the "dynamic" partial components of the backscattered field to the full backscattered field is obtained. At the same time the "dynamic" partial components of the backscattered field and the full backscattered field are detected by the ring detector with the set value of ring aperture radius. Also it was shown that the dependences of the backscattering coefficient on the ring detector radius calculated for all simulated medium has an asymptotic value. The ratio of the asymptotic values of backscattering coefficient is determined by the ratio of the "dynamic" inclusion diameters. The displacing of the "dynamic" object along the surface relative to the point of laser light incidence lead to reducing of the asymptotic value of the backscattering coefficient.

Basic features of combined-discharge low-temperature plasma formation around the surfaces of complex-contoured metal units are considered. It is shown that it makes the possibilities for synthesis of hardened high-durable coatings of hard tools appropriate for material processing in extreme load-temperature conditions. Experimental study of the coating formation was carried out in combination with the analysis of emission spectra of a low-temperature plasma cloud. Some practical examples of the coating applications are presented.

The article deals with the experimental study of the relationship of parameters of combined discharge low temperature plasma with the parameters of its formation process: input SHF power and displacement potential. The purpose of the study is to increase the efficiency of the plasma impact on the surface of parts or products according to the criterion of the formation in the surface layer of composite structures enhancing their operational reliability.

The study results revealed that, firstly, the level of input SHF power is responsible for the intensity of ionization processes at the outer boundary of the plasma; the potential supplied to the product is responsible for generating a compensated flow at the inner boundary of the plasma, and secondly, the processes occurring in the plasma must be controlled. This will ensure consistency of the desired speed and, consequently, the degree of surface heating within a set time, and, on this basis, the increase in the reproducibility of the composite structure synthesis in the surface layer of parts or products, including structures with desired properties.

This work is dedicated to the research of the clinical diagnosis method of determining the antioxidant status of the human body. The existing methods for determining the level of antioxidants in connection with biological functions of the human antioxidant system were studied. Antioxidants in the human body, in the form of solutions were chosen as a research objects. The technique of experimental studies of ubiquinone solutions in oil and alcohol by spectroscopic method was offered. The experimental results connected with the optical density and color characteristics confirm the possibility of applying the clinical diagnosis method of estimation antioxidant balance. Also, it was found that this method can be applicable to the quality control of medicines for treating diseases provoked by oxidative stress, which means that this method may be developed not only for using in the clinic.

Imaging techniques in biology and medicine are crucial tools to obtain information on structural and functional properties of living cells and organisms. To fulfill the requirements associated with application of these techniques it appears necessary to design markers with specific characteristics. Luminescent complexes of trivalent lanthanide ions with chelating ligands are of increasing importance in biomedical applications because of their millisecond luminescence lifetime, narrow emission band, high signal-to-noise ratio and minimal photodamage to biological samples. In order to extend the available emission wavelength range the luminescent samarium chelates are highly desirable. In this study the ligands with diamides of 2,2’-bipyridin-6,6’-dicarboxylic acid were used to improve photophysical characteristics of samarium complexes. We report the luminescence characteristics of samarium complexes with novel ligands. All complexes exhibited the characteristic emission of Sm (III) ion with the lines at 565, 597, 605, 645 and 654 nm, the intensity strongly depended on the ligand. Absorption and luminescence excitation spectra of Sm (III) complexes showed main peaks in the UV range demonstrating lanthanide coordination to the ligand. The absolute lumenescence quantum yield was measured for solutions in acetonitrile with excitation at 350 nm. The largest luminescence quantum yield was found for the samarium complex Bipy 6MePy Sm (3%) being much higher that for samarium complexes reported in the literature earlier. These results prove as well that samarium chelates are potential markers for multiparametric imaging techniques.

In this research carried out control of heavy metals on the territory of a large aviation company using an optical method of control. As the biological indicators of heavy metals were used the leaves of plants. As a result of research was performed bivariate analysis entered the optical coefficients at wavenumbers 1150 cm^-1, 1547 cm^-1 and 1600 cm^-1, on the basis of which the identified zones aircraft factory exposed most contaminated with manganese and copper.

The research of results are confirmed by chemical analysis of the soil.

The results of studies on the effects of heavy metals on aquatic plants using the method of Raman spectroscopy (RS). Introduced optical coefficient, reflecting changes in chlorophyll and carotinoids in relation to the hemicellulose under the influence of heavy metals, defined as the ratio of the intensities of the RS on the wavenumbers 1547 cm^-1, 1522 cm^-1 to the intensity of the line 1734 cm^-1. Was monitored waters of the Samara region on the basis of this coefficient.

One of the problems of modern medical device engineering is the development of an instrument for non-invasive monitoring of glucose levels in the blood. The urgency of this task is ensured by the following facts: the increase in the incidence of diabetes, the need for regular monitoring of blood sugar, and pain of modern methods of glycemia measurement. The problem can be solved with the help of a spectrophotometric method. This report is devoted to the investigation of spectral characteristics of glucose solution with various molar concentrations. The authors proposed the methodology of experimental research and data processing algorithm. The results of the experimental studies confirmed potential opportunity of blood sugar control by spectrophotometric method. Further research is expected to continue by the way of complication of the composition of the object from an aqueous solution of glucose to biological object.

The calculations of the geometrical parameters, frequencies of normal fluctuations and intensity in IR-spectrums of some metalloforbids (Mg-, Zn-, Cu-, Fe-e and Ni-forbid) have been performed by the matrix isolation technique B3LYP/6-311+G (d, p). In this article the absorption bands in IRspectra sensitive to the nature of the metal’s central ion were defined too. The correlations between the force of the interaction of the central ion of the metal with porphyrin macrocycle and the series of changes in the structural parameters have been established.

This work presents the results of study of the influence of BDND on hydrogen bonds of protonic solvents. In addition, the comparative analysis of the interactions of BDND and DND-COOH with solvents molecules was carried out. The analysis of temperature dependences of the quantitative characteristics of the stretching bands of OH groups of the solvents and the suspensions of NDs has shown that the BDND and DND differently weaken the hydrogen bonds in water and in water-ethanol solution with 70 vol. % ethanol content. In water-ethanol solution with 20 vol. % of ethanol the both NDs practically does not change the network of hydrogen bonds.

The optical activity of chitosan films in the forms of polysalt (chitosan acetate) and polybase was studied. The specific optical rotation [α] of all our films was negative. The absolute values of [α] of polybasic chitosan films was by an order of magnitude higher than that for polysalt films. A dependence of [α] on the orientation angle of the sample relative to the direction of the polarization vector of the incident light beam in the plane perpendicular to this beam was established. Specific optical rotation indicatrices of the chitosan films of both chemical forms were plotted.

The optical anisotropy and optical activity of salt and basic chitosan films, both initial and modified in formic acid vapor were studied. The modification of such films was found to be accompanied by induced time-stable optical anisotropy, by varying the values of specific optical rotation [α] and an inversion of the sign of [α]. The angular dependences (indicatrices) of the specific optical rotation of films on the orientation angle of the sample relative to the direction of the polarization vector of the incident light beam in a plane perpendicular to the beam were obtained. The indicatrices of the initial chitosan films have an almost symmetrical character while those of the films modified in formic acid vapor are irregular. It is concluded of the formation of a vitrified cholesteric mesophase in the chitosan films with induced optical anisotropy.

The optical properties of aqueous chitosan solutions in L- and D-ascorbic acids were studied by optical rotatory dispersion and spectrophotometry. The specific optical rotation [α] of all chitosan solutions tested was positive, in contrast to aqueous solutions of the ascorbic acid enantiomers, which exhibit an inverse relationship of [α] values. Significant differences in the absolute values of [α] of the chitosan solutions at polymer-acid ratios exceeding the equimolar one were found.

We analyze two methods of quasi-potential definition at research of superfine shift in the hydrogen-like and exotic atoms. Limits of applicability of each of them are defined.

We analyze ways to eliminate infrared singularities in research of the fine shift in hydrogen-like and exotic atoms. We show the necessity of consideration the kinematic part of the quasipotential for the correct perturbation theory construction.

The work is a numerical and experimental study of closely spaced light spot production using diffractive optical elements (DOE). It is shown that low indexed Hermite–Gaussian mode formers coupled with an objective can be utilized for the production of contrasting closely spaced small light spots in objective focus. Using a tunable laser (EKSPLA NT 242), we demonstrate that low indexed mode forming is quite resistant to chromatic dispersion, but is extremely sensitive to shifting axes of the incident beam and the element.

The numerical model for dynamics of long fiber ring Raman laser is proposed. The model is based on the transport equations and Courant-Isaacson-Rees numerical method. Different regimes of a long ring fiber Raman laser are investigated.

We investigate complex dynamics of two coupled nonidentical Land-Kobayashi oscillators. It is shown that at low values of feedback rate variation of delay only leads to alternation of periodic and stationary regimes. The analysis of characteristic regimes of the system in a wide range of parameters is provided. We demonstrate that the system under study is multistable. With the variation of control parameters sole fixed point repeatedly undergoes supercritical Andronov-Hopf bifurcations, which leads to an increase in the number of limit cycles co-existing in the phase space. It is shown that multistable states are formed by different combinations of the periodic, quasi-periodic and chaotic regimes.

Using the master equation approach, we investigate the stationary regime of a single-emitter laser: an incoherently pumped single two-level system interacting with a single cavity mode of finite finesse. We analyze the closed equation for the phase-averaged Glauber-Sudarshan P function and obtain its approximate solution. This solution has some advantages over the previous results. In particular, it describes conversion from the classical-like probability distribution to the oscillating quasi-probability when transition from weak- to strong-coupling regime takes place.

The numerical simulation results of radiations evolution in the presence of electromagnetically induced transparency for J=0→J=1→J=2 scheme of degenerate quantum transitions are presented. The pulse regime of wave interaction with Doppler broadening spectral lines was investigated. It was indicated that when the control field is linear polarized, the input circular polarized probe pulse breaks up in the medium into pulses with mutually perpendicular linear polarizations. Polarization direction of one of these pulses coincides with the polarization direction of control fields. The distance, which probe pulse passes in the medium to its full separation, decreases, when input probe pulse duration or control field intensity decreases. The input probe pulse intensity variation almost does not influence separation distance and speed of the linear polarized probe pulses in the medium. The effects, described above, may be interpreted as the birefringence effects of electromagnetically induced transparency in the case of short probe pulse.

3D boundary-value problem (BVP) that arises in modelling the interactions of two-electron quantum systems (atoms or ions) with laser radiation, is formulated in the internal coordinate frame with the electrons placed in the focal points of the spheroidal system of coordinates with mapping on a hyper-sphere.^{1, 2} The wave function is sought for in the form of a decomposition in the basis of surface functions of the Coulomb two-center problem having the purely discrete spectrum and parametrically depending on the hyper-sphere hyper-radius. Surface functions are sought for in the form of an expansion in the basis of Legendre polynomials with unknown components calculated as solutions of the reduced problem. Efficiency of the approach in comparison with that of the conventional hyper-spherical one^{3, 4} is demonstrated by the example of helium atom.

The interaction of a few-cycle pulse with a substance, described in terms of density matrix formalism, is investigated numerically. The influence of disordered layered structure, covering the substance, is studied. The material of disordered structure is assumed to be linear and is described in terms of classic electrodynamics. The appearance of additional spectral features, unrelated to the substance material, is demonstrated.

Relaxation of a three-level atom with non-equidistant spectrum interacting with a thermostat and an external stochastic field is studied. The master equation for the reduced density matrix and its solution in the first order of the perturbation theory are obtained. Using quantum regression theorem, explicit formulas for two-time correlation functions and shapes of radiation lines are derived for all types of three-level atoms and the following stochastic processes: a delta-correlated process and a Kubo-Anderson process. The influence of stochastic perturbations of atom’s energy levels and damping constants of adjacent transitions on width of radiation lines is shown.

The relaxation of a pair of dipole-dipole interacting two-level atoms with parallel dipole moments in a large dissipative system is studied on the basis of the generalized coherent states method. The Fokker-Planck equation and its exact solution are obtained. Explicit formulas for two-time correlation functions are given. The influence of the magnitude of the interaction on the shape of the radiation line is investigated.

We provide analytical, numerical and experimental study of the possibility of forming elongated optical bottle beams (OBBs) using composite binary phase axicons. In this case, the OBB is generated by the superposition of Bessel beams in the near-field region on the axicon. To generate the OBB experimentally, we utilized a spatial light modulator. The experimental results are qualitatively consistent with the results of numerical simulations performed using Fresnel transform. Such type of optical trap can be applied in many applications of microbiology, micromechanics and meteorology to manipulate micro- and nanoobjects in liquid or gaseous medium.

Optical properties of open-ended single-wall carbon nanotubes (SWCNT) are investigated by numerical simulation. Different types of carbon nanotubes - with armchair and zigzag configurations - are considered. By numerical simulation total polarizability is investigated for various lengths and for different structures of SWCNT. The new semi-analytical procedure for calculation a total polarizability for long-chain compounds is offered and tested on examples of single-wall carbon nanotubes.

New suitable numerical scheme is proposed for simulation of dynamics of oppositely running pulses in a fiber laser with linear cavity. The proposed model allows to include various temporal and spatial effects which affect the laser dynamics. The pulse evolution in the fiber cavity with perfect reflectors at the fiber ends with accounting of fiber group velocity dispersion and self-phase modulation is demonstrated.

Tight focusing of a linearly-polarized asymmetric Bessel beam, which has a crescent profile, was investigated numerically and experimentally. FDTD calculations show that a binary zone plate of numerical aperture NA = 0.995 forms a crescent in the focal plane, which is rotated clockwise around the optical axis, moving away from the focal plane. Using the Debye formulae it was shown that a direction of polarization of incident light has a significant influence on intensity distribution in focal plane. The crescent in the focal plane was also observed experimentally by focusing of the asymmetric Bessel beam using an immersive objective (NA = 1.25).

The excitation of photonic band-gap modes of all-solid photonic bandgap fibre (PBF) is considered. Inclusion of artificial structure defects allows to create absorption bands on desired wavelength range. Increase of the radius of two high-refractive index rods adjacent to PBF core allows to tailor transmission bands. The proposed approach is useful in PBF filters designing.

We have investigated the influence of dipole-dipole interaction and initial atomic coherence on atomic entanglement dynamics of two qubits. We have considered a model, in which only one atom couples to a quantum electromagnetic field in a cavity, since one of them can move around the cavity. We have shown that the entanglement arises for all pure atomic state even when both atoms are initially in the excited states. We have also derived that degree of entanglement is enhanced in the presence of the atomic coherence.

We study the entanglement properties of a pair of two-level atoms going through a thermal cavity one after another. The initial joint states of two successive atoms that enter the cavity are coherent or entangled. Using the exact solution of density matrix evolution equation we calculated the negativity for different values of cavity mean photon numbers. We shown the possibility to save the initial atomic entanglement even for a thermal cavity field with relatively high temperature.

We investigated the entanglement dynamics in a quantum system consisting of three two-level atoms resonantly coupled to a single mode electromagnetic field. We considered the dynamics of the system under consideration for Fock and thermal initial cavity states. An explicit analytical solution of the system has been obtained and the entanglement has been studied with the help of the two-qubit negativity. It was also shown that for both initial cavity states the sudden death of two-qubit entanglement takes place.

A coherent dynamics of a three-level atoms in the ideal cavity were investigated. This model evidently generalizes the well-known Tavis-Cummings model of two-level atoms. We have derived a system of equations for the parameters of coherent states associated with the group G = W₂˄SU(3). It is shown that this model gives a nontrivial example of the chaotic behavior of the parameters of coherent states, taking into account non-resonant terms in the Hamiltonian. Time dependencies of mean number of the cavity photons and level populations of atoms are computed and maximal Lyapunov coefficient is calculated.

The method of measurement of the power (lux-ampere) characteristic of photodetectors for work with the continuous laser sources of light which radiation has the linear polarization is developed and realized.

The way offered in this work is approved on the basis of the FD-24K widespread photo diode. The received results quite correspond to passport data of this kind of photodetectors. Methods of statistical processing of results are applied.

Metal-porous cathode is an electrovacuum EHF device, providing a high density of emission current. The emitting surface of the device is usually obtained by ion etching. The emitting layer is made of a porous sponge of a refractory metal, usually tungsten. Through the pores of the sponge alkaline earth metals and their oxides are delivered to the emitting surface. One of the most important parameters of the cathode is a uniformity of emission, depending on regularity of the location of pores.

We describe a method of laser modification of metal-porous cathode surface, instead of traditional ion etching. The preferences of laser etching are uniformity of pores, absence of deformation of surface, opportunity to specify the necessary size of the pores and the distance between them.

Laser structuring of the cathode surface was implemented by laser micrograving. The resulting structure is a field of pores, diameter 15 μm, with spacing of 20 μm.

The reflection/transmission coefficients for the hyperbolic finite-thickness SiC-graphene slab are calculated using the 4x4 Berreman matrix method for arbitrary orientation of optical axis according to slab boundary. Gain or losses in the medium are described as imaginary parts of the components of dielectric tensor of the medium. The threshold conditions for gain of THz waves and radiation angle were calculated for given losses and axis orientation.

A model of the laser pulse propagation through a medium with a special mechanism of optical limiting - the effect of the reverse saturated absorption - was proposed. It is shown that the propagation through three-level medium with reverse saturable absorption leads to decrease duration and transformation of the profile of the pulse. Analytical expressions for the maximum intensity shift and change of duration of the laser pulse were obtained.

An important problem of investigation of the air and water contamination by the mid-IR spectroscopy is discussed. A model of evanescent wave sensor made of a multimode waveguide transparent in the mid-IR spectral range is developed. Transmittance and sensitivity of a sensing element consisting of an input chalcogenide waveguide and a sensing waveguide depend on distribution of the guided modes amplitudes in the sensing waveguide. We have demonstrated that excitation of higher-order modes is important for optimal performance of such a sensor.

We introduce a new type of microresonator for frequency selection in a terahertz (THz) generator. The THz source by itself is based on intracavity difference frequency generation in two-color fiber laser. We show that asymmetrical nanoscale deformation can fully localize whispering gallery modes and filter out two modes for difference frequency generation with high effectiveness. Our theory confirms localization of whispering gallery modes (WGMs) for typical longitudinal dimensions of the microresonator 10-100 μm. In this case the theory is in excellent agreement with the experimental results obtained previously. A simple condition for the stability of this geodesic corresponding to the appearance of a high Q-factor nanobump microresonator is found.

The dispersion equation and the analysis and homogenization in periodic and quasiperiodic plane layered structures with alternating dielectric layers of metal and dielectric layers, as well as a graphene sheet and SiO₂ layers have been investigated. The cases are considered when these patterns become the properties of hyperbolic metamaterials, i.e., having different signs of the real parts of the tensor components of the effective dielectric constant. It is shown that usage only dielectric layers is perspective in reducing losses.

The application of extended Kalman particle filter for dynamic estimation of interferometric signal parameters is considered. A detail description of the algorithm is given. Proposed algorithm allows obtaining satisfactory estimates of model interferometric signals even in the presence of erroneous information on model signal parameters. It provides twice as high calculation speed in comparison with conventional particle filter by reducing the number of vectors approximating probability density function of signal parameters distribution

The purpose of this study is to compare image denoising techniques based on real and complex wavelet-transforms. Possibilities provided by the classical discrete wavelet transform (DWT) with hard and soft thresholding are considered, and influences of the wavelet basis and image resizing are discussed. The quality of image denoising for the standard 2-D DWT and the dual-tree complex wavelet transform (DT-CWT) is studied. It is shown that DT-CWT outperforms 2-D DWT at the appropriate selection of the threshold level.

We discuss the problem of quantifying chaotic dynamics at the input of the “integrate-and-fire” (IF) model from the output sequences of interspike intervals (ISIs) for the case when the fluctuating threshold level leads to the appearance of noise in ISI series. We propose a way to detect an ability of computing dynamical characteristics of the input dynamics and the level of noise in the output point processes. The proposed approach is based on the dependence of the largest Lyapunov exponent from the maximal orientation error used at the estimation of the averaged rate of divergence of nearby phase trajectories.

We discuss the phenomenon of multifractality loss in the dynamics of nonlinear systems. Based on computer simulations, we analyze features of deterministic and stochastic dynamics of coupled oscillators and a reduction of the multifractality degree with varying noise intensity. We consider analogous effect of multifractality loss in the cardiovascular dynamics.

We proposed the model of cardiovascular system which describes the sinus rhythm, autonomic regulation of heart and arterial vessels, baroreflex, arterial pressure and respiration process. The model included a self-oscillating loop of regulation of mean arterial pressure. It was shown that suggested model more accurately simulated the spectral and statistical characteristics of heart rate variability signal in comparison with the model proposed earlier by Seidel and Herzel.

A generalized model of star-like network is suggested that takes into account non-additive coupling and nonlinear transformation of coupling variables. For this model a method of analysis of synchronized cluster stability is developed. Using this method three star-like networks based on Ikeda, predator-prey and Hénon maps are studied.