This PDF file contains the front matter associated with SPIE Proceedings Volume 11065, including the Title Page, Copyright information, Table of Contents, Author and Conference Committee lists.

We present an optical coherence tomography (OCT) lymphangiography visualization approach based on analysis of speckle statistics. For in-vivo experimentation, normal and tumor tissues are examined in mouse dorsal skin window chamber model. In order to evaluate the speckle statistics, OCT datasets are acquired in 3 spatial and 1 temporal dimensions to be divided then into smaller volumes of interests. In temporal dimension, repeated same-location scanning is performed for simultaneous blood vessel detection through speckle variance processing. Speckle statistics in each volume of interest are tested for similarity to known distributions corresponding either to noise or to tissue. We show that lymphatic vessels could be detected using a specific parameter range of speckle statistics as a filter, to separate the surrounding tissues and blood vessels. The proposed approach does not require numerous post-processing steps that are often used in lymphatic detection methods that are based on low signal amplitude regions (e.g., OCT signal attenuation compensation, inversion, amplitude thresholding etc.). Instead, we use a fast 2-step filtering procedure to reveal lymphatic vessels in imaged tissues.

In this report we present a scanning system and signal processing for three-dimensional strain mapping based on optical coherence tomography. This approach allows evaluating the tissue deformation in 3D for both quasistatic elastography (OCE) and monitoring of slowly relaxing strains (mechanical relaxations, creeps, etc.). Experimental demonstrations of 3D OCE are performed using silicone layer with known structure located on excised breast cancer tissue. It is important to note that in the described variant of OCE we perform aperiodic loading of the tissue not-synchronized with scanning. Because entire 3D datasets are acquired only twice (before and after deformation) it is crucial to ensure that there is already no tissue creep in the deformed state. Experimental demonstrations of monitoring slow processes are performed for visualization of drying of cartilaginous sample. Slow deformation may be undetectable on inter-B-scan intervals because such strain values may be well below minimal detectable level. However, for wider intervals (typical for 3D datasets acquisition), strains can attain an order of magnitude higher level that can be detectable and used for further relaxation parameters calculations. We discuss the applicable scanning patterns and signal processing optimizations.

Gastrointestinal tract neoplasia is on the third place of death statistics among oncological diseases, which is associated with the difficulty of early diagnosis of this disease. This study aims to evaluate applicability of delta-aminolevulinic acid / protoporphyrin IX photosensitizer (5-ALA / PpIX) as diagnosing agent for detection of small and large intestine neoplasia. The experiments were performed in vivo on white laboratorial rats. The animals were divided into 2 groups: control and experimental (overpopulation social stress and a diet, including nitrites and amines) ones. The results of the studies, averaged for each type of tissue, clearly show significant differences between normal tissues and malignant intestine tissues of the rats useful for fluorescent-based discrimination of the tissue state. The fluorescence from malignant areas in small and large intestine represented bright red fluorescence with specific maxima at 635 and 704 nm, typical for PpIX, due to the high accumulation of this photosensitizer in the affected tissues. The accumulation of protoporphyrin IX in the intestine cancerous tissues was very well pronounced. A contrast achieved between normal and abnormal tissue sites at 635 nm fluorescence emission was more than an order of magnitude in the case of large intestine neoplasia, which allows using the 5-ALA/PpIX as a sensitive indicator of gastrointestinal carcinoma.

Optical clearing of the human skin under the action of hyaluronic acid (HA) as an enhancer for optical clearing by polyethylene glycol (PEG-300) was studied in vivo by optical coherent tomography (OCT) method on the wavelength 930±5 nm. The results have showed an increase in the transparency of the epidermis at the optical depth of 50±5 μm by 44±9% within 15 min with the use of a solution of HA in combination with sonophoresis before application of PEG-300 to the skin surface. At the same time, when using PEG-300 without preliminary treatment of the skin with the HA, an increase in the transparency of the epidermis at the same depth was 21±8% within 25 min. In dermis at the depth of 500 μm the OCT signal in the experimental group increased more than 1.6 fold what indicates an increasing of optical probing depth.

Normal and pathological tissues are different in their elastic properties. Thus, elastic characteristics of tissues can serve as an additional diagnostic marker to distinguish altered tissues. A number of studies have demonstrated advantages of using optical coherent tomography in clinical practice and research. Here we report the application of optical coherence elastography (OCE) for studying elastic properties of murine breast cancer 4T1. It is known that 4T1 model is convenient for in vivo tumor imaging and is highly relevant to studies of tumor process. In this study the therapy was performed with a cytostatic chemotherapeutic drug cisplatin. We developed the protocol of compressional OCT elastography for long-term in vivo monitoring of tumor response to anti-tumor therapy. The ear tumor model was chosen as optimal for this task. Histological analysis demonstrated good agreement with OCE-based stiffness-mapping results.

Microrheological parameters of red blood cells (RBCs) and blood viscosity were studied by different optical and rheometric techniques. Measurements were performed under in vitro condition both on the EDTA-stabilized whole blood samples at various temperatures and on the RBCs in autologous serum without platelets at different concentrations of proaggregant macromolecules (Dextran 150, Dextran 500 and albumin). The nonlinear dependences of the aggregation parameters on the concentration of the proaggregant macromolecules in autologous serum were observed. Rheometry of human whole blood samples demonstrates a power law dependence of the suspension viscosity on temperature at such shear rates that allow the RBC aggregation. We assume that there may be an unaccounted temperature dependent synergetic effect of plasma proteins/macromolecules on RBC aggregation and interaction and, consequently, on the blood viscosity.

The paper presents the results of in vivo experimental measurements of the endogenous fluorescence and blood perfusion in common bile duct tissues in obstructive jaundice patients during minimally invasive surgical operations. Nowadays the type of interventions become more widespread for treating hepatopancreatobiliary pathologies. An effective feedback which can be established by one or more optical diagnostic channels integrated into the standard instruments for minimally invasive manipulations would be of particular value to practical surgeons. To collect reference data, an experimental study has been conducted using a fiber optical probe with fluorescence spectroscopy and laser Doppler flowmetry channels. For every measurement, the areas of interest were different areas of common bile duct obstructed by a malignant tumor. Obtained results demonstrated significant variety registered intensities of fluorescence spectra and values of blood perfusion. Tested fiber optical endoscopic system showed sensitivity to the tissue state in the investigated area, so the two modal approach seems to be promising for further research and implementation in clinical practice.

The main goal of the study is to investigate the effect of ethanol aqueous solutions with volume concentrations 30, 40, and 50% on the transport of Methylene Blue (MB) in rat skin ex vivo. The concentration dependences of MB absorbance in optical phantoms mimicking skin optical properties were measured. It has been obtained, for skin-like optical phantoms with low MB concentration (less than 0.025 mg/mL) the concentration dependence of MB absorption coefficient can be taken as linear in a first approximation. The study has shown that the diffusion rate grows with the increase of ethanol concentration in the solutions. The rate is 1.6 folds higher for 50%-ethanol solution of MB than when aqueous solution of MB is used. Effective diffusion coefficients of MB in skin samples have been evaluated as (3.34±0.07)×10^-6 cm²/sec, (3.04±0.07)×10^-6 cm²/sec, (2.59±0.07)×10^-6 cm² /sec, and (1.85±0.06)×10^-7 cm²/sec for 50%, 40%, 30% ethanol solutions and aqueous solution, respectively. The characteristic time has the following values: 24.6±4.4 min, 40.1±3.2 min, 46.8±2.7 min, and 79.4±11.9 min for 50%, 40%, 30% aqueous ethanol solutions and aqueous solution, respectively.

This paper presents the results of statistical clinical data, combining two diagnostic methods. A combination of two skin imaging methods – diffuse reflectance and autofluorescence – has been applied for skin cancer diagnostics. Autofluorescence (AF) and multispectral diffuse reflectance images were acquired by custom made prototype with 405 nm, 526 nm, 663 nm and 964 nm LEDs and RGB CMOS camera. Parameter p’ was calculated from diffuse reflectance images under green, red and infrared illumination, AF intensity (I’) was calculated from AF images exited at 405nm wavelength. Obtained results show that criterion p` > 1 gives possibility to discriminate melanomas and different kind of keratosis from other lesions, and criterion I` < 0.2 gives the possibility to discriminate melanomas from keratosis.

Gastric cancer is the main cause of death among oncological diseases of the gastrointestinal tract, which is associated with the difficulty of early diagnosis of this disease. This study aims to develop a new method for diagnosing gastric cancer using the delta-aminolevulinic acid / protoporphyrin IX photosensitizer (5-ALA / PpIX). The experiments were performed on white rats of average weight 250 grams. The animals were divided into 2 groups: control and experimental (stress + diet, including nitrites and carcinogenic amines) ones. The results of the studies, averaged for each type of tissue, clearly show significant differences between normal, precancerous and malignant changes in the stomach tissues of rats on the background of application of photodynamic diagnostics. The fluorescence from malignant neoplasms in the organ was maximal at 635 nm, which corresponds to the maximum emission of protoporphyrin due to the high accumulation of this photosensitizer in the affected tissues. The most important result of the study was the detection of precancerous changes (atrophic gastritis, confirmed by histological methods), using photodynamic diagnostics with photosensitizer 5-ALA / PpIX. Intensity of fluorescence in case of precancerous changes occupied an intermediate value between that in normal and in malignant mucosa of the stomach.

We propose to use an acousto-optic tunable image filtration to implement spectral and phase measurements in nearcommon-path interferometric module based on Michelson interferometer with artificial reference light source. In such two-beam interferometer, reference beam is formed via spatial filtration from one of the light beams. The module may be placed at the output of the imaging device for obtaining wideband images of the inspected object, such as, for example, camera port of transmitted light microscope. Acousto-optical tunable imaging filter is necessary to enable spectral measurements as well as quantitative phase retrieval.

Elastic properties of soft biological tissues may reflect their functional state and be a sensitive indicator of important pathological processes occurring in them. Using compressional optical coherent elastography (OCE) we revealed significant differences not only in the value of the Young modulus, but also in the character of elastic responses of biological tissues in different pathological states (including such key states as inflammatory, oncological and degenerative processes) in ex vivo human tissues. Here, we demonstrate a bright example of such qualitatively and quantitatively different trends: unlike breast cancer characterized by strongly elevated (in comparison with norm) stiffness that pronouncedly increases with compression, stiffness of pelvic organ prolapse is strongly decreased and weakly varies with compression.

This work presents the results of clotting time estimation using the method of laser speckle imaging. The method determines the clotting time blood by calculating correlation coefficient between adjacent laser-speckle images. The study was accomplished with two different samples of blood, i.e. with fresh blood and blood with anticoagulant additive. Statistical analyses of the results obtained under the laboratory conditions provides discussion about the improvement of these methods for practical application for the task of clotting time measurements.

Prototype of laser scanning speckle-microscope has been designed. It has been demonstrated experimentally, that signal of speckle microscope is increased drastically in the presence of gold nanoparticles. It has been demonstrated the unique possibility of detection of a single C. trachomatis cell in a tested sample using speckle-microscopy.

As it has been demonstrated earlier, different types of re-coding of nucleotide sequences to gene-based speckle-patterns (GB-speckles) can be used. In this paper the advanced study, devoted to optimization of the basic algorithm, is presented. With this purpose, investigations of statistical properties of GB-speckles, generated on nucleotide sequences of omp1 gene of Chlamydia trachomatis, has been performed. First- and second-order statistics of intensity fluctuations in GB speckles has been analyzed. Part I of the paper is devoted to investigations of statistical properties of phase fluctuations in GB-speckles.

As it has been demonstrated earlier, different types of re-coding of nucleotide sequences to gene-based speckle-patterns (GB-speckles) can be used. In this paper the advanced study, devoted to optimization of the basic algorithm, is presented. Investigations of statistical properties of GB-speckles, generated on nucleotide sequences of omp1 gene of Chlamydia trachomatis, has been performed. Part II of the present paper is dedicated to analysis of first- and second-order statistics of phase fluctuations in GB-speckles with purpose of optimization of algorithm of re-coding.

GB-speckles, simulated for nucleotide sequences of the omp1 gene of Chlamydia trachomatis, have been processed by s-LASCA technique. Properties of LASCA-images of the GB-speckles have been analyzed. Perspectives of application of suggested technique in modern bioinformatics have been demonstrated. Interference of the GB-speckle, generated for nucleotide sequences of the omp1 gene of different Chlamydia trachomatis strains has been also studied. It has been demonstrated that s-LASCA technique is very helpful tool for detection of natural mutations in bacteria.

For the first time gene-based speckles (GB-speckles) have been applied for analysis of nucleotide sequences of the gene GPCR of the Lumpy Skin Disease Virus (LSDV). The 1st and 2nd order statistics of the 2D speckle structures corresponding to nucleotide sequences of LSDV have been analyzed. It has been shown that these GB-speckles are forming in the case of small number of scatterers and they obey to non-gaussian statistics. It has been demonstrated that application of the GB-speckles, generated on the target virus nucleotide sequences has the great perspectives from viewpoint of modern bioinformatics.

Analysis of structural properties of the interfering GB-speckles, generated for nucleotide sequences of Lumpy Skin Disease Virus (LSDV), has been carried out. It has been shown, that at the interference of two LSDV GB-specklepatterns, three types of interference pictures are forming: quasi-random speckle structure without interference fringes, fringes, modulated by speckles, or having bends and pure regular fringes without visible speckle-modulation. It has been found, that width of fringes and their orientation depend on position of SNP in comparing nucleotide sequences. It has been demonstrated that implication of interference of two GB-speckles, generated on the target virus nucleotide sequences, can be considered as a new direction in modern bioinformatics.

Pulse wave from naïve fertilized chicken eggs has been clearly detected using laser photoplethysmography. Highfrequency modulation of intensity of illuminating laser light has been used to enhance output signal of experimental setup and to increase the S/N ratio. The form of pulse wave has been analyzed for naïve embryo on different stages of their development.

Formation of output signal of device, realizing Doppler technique, has been studied. Naïve embryo (non-infected fertilized chicken eggs) has been used as a test object. Dependence of first frequency-weighted spectral moment of output signal on the day of observation of chicken embryo has been investigated. The possibility of adaption of the Doppler diagnostics for monitoring of viability and detection of pathology of development of chicken embryo, infected with Chlamydia trachomatis cells, is discussed.

Methods of t-LASCA and s-LASCA imaging have been adapted to the problem of monitoring of blood microcirculation in naïve chicken embryo. Set-up for LASCA imaging of the model chicken embryo is mounted. The novel original technique of preparing of optical windows for observation of a naïve chicken embryo is suggested. This technique is based on a removal of part of the natural egg shell using a citric acid solution with further optical clearing using glycerol and glucose.

Method of speckle-microscopy has been adapted to the problem of detection of Chlamydia trachomatis microbial cells in aqueous suspension and fixed on the glass. Combined system “C. trachomatis bacterial cell”-“monoclonal antibody”- “gold nanoparticle” has been used as a complicated scattering element in the case of formation of biospeckles with a small number of scatterers. Optical model of diffraction of strongly focused Gaussian beam on combined scattering system, containing gold nanoparticles, has been suggested. Simulation of speckles, forming with a small number of scattering nanoparticles, has been carried out. It has been demonstrated that the usage of nanoparticles allows to enhance essentially the output signal of speckle-microscope.

Gene-based speckles (GB-speckles) have been implied for interpretation of nucleotide sequences of the target genes of Avian Influenza Virus (AIV). The 1^st and 2^nd order statistics of 2D speckle structures corresponding to the nucleotide sequences of AIV have been analyzed. It has been shown that these GB-speckles are forming in the case of small number of scatterers and they obey to non-Gaussian statistics. These GB-speckles are characterizing by essential spatial inhomogeneity. Potentials of proposed laser speckle technique for the AIV target genes identification are demonstrated.

Diagnosis and treatment of acute destructive pancreatitis is one of the most urgent problems of abdominal surgery. To obtain additional diagnostic information about the microcirculation state and metabolic processes, various imaging techniques are widely used during surgical interventions. One of the most perspective techniques for in vivo microcirculation assessment is laser speckle-contrast imaging (LSCI), allowing for evaluation of blood perfusion. The experimental results showed the possibility to evaluate the blood perfusion of the mouse pancreas in the simulation of ischemia using the LSCI method.

At present, fluorescence spectroscopy (FS) and diffuse reflectance spectroscopy (DRS) are widespread methods highly used in medical practice. The combined application of these methods is a promising tool to improve the predictive force of classifiers for tissue type recognition as well as to compensate the attenuation of the fluorescence radiation by blood for the accurate evaluation of the biomarkers content in living tissue. Several techniques are known to normalize the resulting fluorescence spectrum in order to exclude the attenuation effect. In this study, an approach based on the dividing of the experimentally obtained FS spectrum by DRS spectrum has been applied for experiments with occlusion test. The implemented multimodal approach for the in vivo optical measurements in combination with occlusion test for minimisation of blood influence has shown good repeatability of obtained experimental fluorescence spectra. The results are of particular interest for the further development of methods for compensating the influence of chromophores in optical spectroscopy.

Laser Doppler flowmetry (LDF) was utilized to assess age-related changes in the blood microcirculation at the skin sites with different morphology and regulation. The LDF signals obtained from the glabrous skin of the middle finger pad and nonglabrous skin on the dorsal wrist surface were analyzed. Statistically higher baseline perfusion was observed in the zone with glabrous skin in the older group of volunteers compared to younger participants. Observed site-specific and age-related differences in perfusion can be used in the future experimental design for the studies of the blood microcirculation system in patients with different pathologies.

Videocapillaroscopy (VCS) and laser Doppler flowmetry (LDF) are non-invasive methods for evaluating microcirculation parameters. The VCS method is based on a high-speed video recording of capillaries in the nailfold. The recorded video frames are processed using a specialized algorithm to determine the red blood cells velocity. The LDF technique is based on the analysis of the Doppler shift of back-scattered laser radiation from moving red blood cells. In this work, simultaneous measurements of VCS and LDF have been performed in healthy volunteers and rheumatic patient. The study was conducted using a cold pressor test. Changes were recorded in response to cold exposure in rheumatic diseases.

Studying the reversible aggregation of red blood cells (RBC), which is one of the main factors determining the blood microcirculation is of importance for modern cardiology because the widespread application of different antiplatelet agents and anticoagulants in clinical practice may affect the blood rheology also via the alteration of RBC aggregation. Administration of the antiplatelet and anticoagulants agents into blood is based on general assumptions about the average doses of the drug, which often do not fully comply with the requirements of the personalized medicine. In this work, we compare the blood aggregation properties measured by laser aggegometry techniques in-vitro in blood samples with the properties of blood rheology measured with digital capillaroscopy in-vivo in the nail beds capillaries of patients suffering from the coronary heart disease (CHD). We demonstrate the impairment of these properties and high correlation of their alterations for patients suffering from the CHD with different stages of rheology disorders. Good agreement between the results obtained with the used diagnostic techniques, laser aggregometry, laser tweezers and digital capillaroscopy, and their applicability for the diagnostics of abnormalities of rheological properties of blood are demonstrated.

Based on the developed electro-optical cell detection system using dielectrophoresis, both the electrical and viscoelastic behavior of erythrocytes was studied. Studies were conducted to assess the possibility of using hemorheological parameters as precursors of stroke recurrence. As a result, the main hemorheological parameters of erythrocytes, such as electrical and viscoelastic properties, hemostasis indices, were determined. It is shown that these parameters can serve as harbingers of a relapse of a stroke.

The algorithm for obtaining high-quality structural images in endoscopic optical coherence tomography with a reduced level of speckle noise is described. The key features of the developed algorithm are the multilevel filtering and morphological digital processing of structural images. Structural images of soft biological tissues in vivo and tissue-like phantoms are shown. The suggested algorithm can be used to improve quality of structural images not only in optical methods of visualization and non-destructive testing, but also in ultrasonic ones.

The method of longitudinal elasticity modulus evaluation for the large blood vessel wall is presented. It is based on obtaining and computer analyzing structural images of the same section of the investigated blood vessel wall at the moments correspondent to systole and diastole. Endoscopic optical coherence tomography system with a forward-side probe was used by the structural images raw data acquisition. Digital analysis of structural images includes noise reduction, detection of control points, combination them together and calculation of relative displacements. The Young's modulus was calculated taking into account the surface area of the scanning region, the coherence probing depth and the magnitude of the deformation impact of the pulse wave.

A borderline reconstruction algorithm of optical structure disturbances of biomedical objects is described. The key features of it: (I) determination of the coordinates of the centers and effective size of each absorbing and scattering inhomogeneity in an investigated biological tissue, (II) refinement of the convex and concave parts of the boundary of each spherical inhomogeneity which is followed by smoothing the resulting structural image. The refinement of the parts of the boundary of a spherical inhomogeneity was made by adding or subtracting additional spheres. Centers of additional spheres were determined stochastically in the neighborhood of the boundary of the spherical inhomogeneity. Radii of additional spheres were calculated as one quarter of the length of the distance from the center of the additional sphere to the center of the spherical inhomogeneity.

The method for obtaining functional images of human brain or another soft biological tissue and its phantoms based on the time-resolved diffuse optical tomography is described. The developed method is based on the principles of near infrared spectroscopy, in particular on the increased probing depth in optical transparency window and the differences in the absorption spectra of oxygenated and deoxygenated blood. The key feature of the approach is fast search and dynamical visualization of the most oxygenated sections of an investigated object using improved mapping algorithm for localization of absorbing inhomogeneities. Hydrodynamic phantoms with pulsatile blood flow in the thickness of biological tissues were used for validation of the described method.

The search for new non-invasive methods of research in medicine and physiology is an urgent task of the modern development of human sciences. One of the most attractive options for solving this problem is to recognize the use of human saliva as an object of research. The results obtained confirm that oral fluid facies is a simple, noninvasive, lowcost method for additional assessment of the human organism’s functional state, applicable to the population mass screening. The morphological picture of the oral fluid facies and the results of its computer morphometry are consistently combined with the human level of general nonspecific reactivity of an organism (LGNRO) and have a distinct circadian dynamics of the main parameters. The qualitative characteristics analysis of the facies’ peripheral zone (size and homogeneous protein deposits, the structure of the boundary between the outer and inner zones) and their quantitative equivalents (thickness and intensity of crystal formation) have been proved to be the most informative when analyzing the human oral fluid facies

A new approach to measure changes of polarization state of the light scattered from a biological object using crosspolarization and polarimetry imagining technique is considered. The method is based on the calculation of the coefficient of residual polarization. Two experimental setups based on incoherent white light source and infrared light source for imaging of the skin pathology with polarimetric detection and processing are developed. The results of two experimental setups are compared and analyzed. The experimental setup based on infrared light source allows one to get better results than the experimental setup based on white light source, because the depth of penetration of infrared radiation is ten times greater than the depth of penetration of visible light.

The paper discusses the influence of time profile of microsecond Yb,Er:Glass laser pulse on removal efficiency of cataract lens when performing its laser hydroacoustic processing. It was established that the increase in peak power of the "leading" spike of Yb,Er:Glass microsecond pulse leads to increase in volume of laser-produced steam-gas cavities in liquid, increase in pressure transient amplitude arising in the phase of "collapse-rebound" of the cavity and increase in removed volume of cataract lens as a result of its laser hydroacoustic processing (LHP). Increasing the peak power of the "leading" spike by 2.5÷3 times while keeping the total integral laser pulse energy resulted in a 5÷7-fold increase in the removed volume of human eye lens with III degree of cataract according to L. Buratto classification. The possible multipulse mechanism of cataract lens removal when performing LHP with microsecond Yb,Er:Glass laser pulses is discussed.

The effectiveness of the application of the laser fractional treatment to remove scars of the oral mucosa has been investigated. For the first time it has been demonstrated that laser fractional treatment by diode laser radiation with a wavelength of 980 nm, power 7 W and pulse duration 120 ms leads to the disappearance of scar on human oral mucosa.

The structure of a titanium-doped optothermal fiber converter used in contact laser surgery for resection and coagulation of soft tissues was studied. Structural, optical, and thermophysical models of this converter are proposed. Optical and thermal calculations performed within the framework of the proposed models made it possible to estimate the fraction of laser energy absorbed by the converter and the dynamics of its laser heating. The results obtained were compared with the experimental data on the heating of a titanium-doped optothermal fiber converter by the radiation of a 980 nm diode laser in air. The influence of temperature dependences of physical density, specific heat capacity, thermal conductivity coefficient, converter blackness degree, and converter-air and fiber-air heat transfer coefficient on the dynamics of laser heating of the converter are discussed. It is shown that the greatest contribution to the simulation results is made by the temperature dependences of specific heat and converter blackness degree. The results obtained in the work should be taken into account in the future when creating a general model that adequately describes the interaction between the converter and biological tissue in the process of surgical intervention.

The consistent patterns for local temperature fields under laser irradiation of biological tissue doped by effectively absorbing plasmon gold nanostars are discussed. Differences in the degree of spatial localization and the kinetics of the photoinduced temperature fields under irradiation by femto-, pico- and nanosecond pulses are revealed.

In this paper, a theoretical model of the formation of a local temperature field in suspensions of microorganisms with embedded plasmonic gold nanorods under irradiation by low-intensity NIR laser light was considered. The results of numerical modeling of the optical properties of plasmon nanorods used in the experiments, and the results of multiscale modeling of the parameters of local hyperthermia with various types of distribution of the concentration of plasmon nanoparticles are presented. Found that the process of concentration of nanoparticles, functionalized with human immune globulins IgA and IgG, around the cells of microorganisms with the formation of "clouds" leads to the appearance of a microscale zone of elevated temperature. This ensures a synergistic effect of a multiplicative increase in the volume of the hyperthermia zone. The results of numerical simulation provide a justification for the experimentally observed increase in the bacterium killing ability at laser hyperthermia of the cellular environment doped with functionalized nanoparticles, without a noticeable increment in the recorded average sample temperature when irradiated with a low intensity laser beam of around 100 mW/cm².

It is reported on pilot clinical study of photodynamic therapy (PDT) of onychomycosis with high-intensive LED device with a wavelength of 660±10 nm. The possibilities of achieving a positive result after PDT of onychomycosis using this high-intensive LED device are demonstrated. It was found that the average growth of the novel healthy nail area after PDT is 6.25% per a month.

The study of antimicrobial photodynamic activity of subingibing concentrations of aqueous solutions of silver nanoparticles under the photodynamic action of blue led radiation in relation to the standard and clinical strain of Staphylococcus aureus. The greatest sensitivity to the combined effects of radiation and metal nanoparticles showed methicillin-resistant clinical strain of Staphylococcus aureus. The samples containing silver nanoparticles presented in the experiment were characterized by a pronounced antimicrobial activity and can be considered as promising photosensitizers for photodynamic therapy of pyoinflammatory diseases.

The work is devoted to the determination of the antibacterial activity of methylene blue under the action of ultraviolet radiation, laser radiation (660 nm), as well as their combined effect on standard strains of the bacteria Candida albicans, Staphylococcus aureus FDA 209P and Lactobacillus in vitro. When exposed to all the tested strains, a tendency was revealed with the most pronounced inhibitory effect with the combined action of laser and ultraviolet radiation together with the MB solution. Clinical studies of the in vivo use of methylene blue with the combined effect of ultraviolet and laser radiation (660 nm) in the treatment of chronic recurrent aphthous stomatitis in humans have also been conducted.

The work is dedicated to fabrication and study of SERS-active nanocomposites based on aluminum hydroxide with incorporated copper nanoparticles (CuNP; 10±2 nm). The initial CuNP and the final composite were characterized using SEM, EDX, STM, and absorbance spectroscopy in UV-visible range. The application of incorporation enabled to improve temporal stability of SERS-activity of the CuNP against oxidation to around 80 times compare to colloidal CuNP; the composite is SERS-active for more than 8 days. The value of Raman enhancement was found around 8×10⁶ that is comparable with the values for silver and gold based SERS substrates. The applicability of the final composite for chemical analysis was demonstrated by SERS detection of some drugs, such as antitumor (methotrexate) and antibacterial drugs (lincomycin, sulfadimethoxine, ceftriaxone). The analytes were detected at concentrations which have to be detected at physiological conditions in urine (50‒100 μg/mL) after medical treatment.

One of the most effective ways of targeted drug delivery is the intravenous injection of carriers. However, to prevent undesirable side effects it is necessary to develop microencapsulation drug delivery systems that satisfy following requirements: biocompatibility, non-cytotoxity, biodegradability, colloidal stability in different medium solutions. In case of polymeric microcapsules, aggregation is a crucial and challenging question for biomedical applications that has not been studied well yet. We investigated polymeric microcapsules behavior in PBS, human plasma, and human blood in time. Aggregation degree was measured after 1, 10, 30, and 60 minutes of incubation in a stationary state. As a result, dynamics of capsules aggregation was shown for each medium.

One of the most interesting modern platforms for fiber-optic biosensor are microstructured optical fibers. The analytical signal in label-free analysis can be determined by the following mechanisms: changes in the thickness of biomolecule layers immobilized on the surface of the fiber hollow fiber core; small changes in the refractive index of the analyzed solution in the fiber hollow core of the fiber and the absorption spectrum of the analyzed solution. In this article, we report data on the effect of different salt solutions small concentration changes on the MOF HC transmission spectra

In this article, we report the effect of the pH of bovine serum albumin and egg serum albumin solutions on the microstructured optical fiber transmission spectra fluctuations near proteins isoelectric point. The demonstrated effect may be important in the development of perspective optical microstructured optical fiber-based biosensors in a labeled and label-free formats for a wide range of analytes.

An ability to use sapphire hollow-core terahertz (THz) waveguides for high-temperature intrawaveguide spectroscopy was studied experimentally. We assembled an experimental setup, which employs the principles of THz intrawaveguide spectroscopy and uses a backward wave oscillator, as a continuous-wave THz source with tunable output frequency, and a Golay cell, as a detector of THz wave intensity. In this setup, the sapphire shaped crystal serves simultaneously as an optical waveguide and as a sample cuvette; the analyte is placed in its central hollow channel. We applied the setup for high-temperature measurements of sodium nitrite (NaNO₂) powder. The observed results demonstrate an ability to sense melting of NaNO₂-powder; justifying a prospect of sapphire waveguides in THz measurements in harsh environments, at high temperatures and pressures.

In the study, morphology, composition, and hardness of the coatings formed by electrospark alloying (ESA) of titanium with zirconium and subsequent induction heat treatment were considered. The possibility of forming coatings with a maximum size of oxide crystals of 8.9±3.8 μm and an open porosity reaching 58 % was established. The morphology parameters depend on the modes of electrospark alloying and heat treatment. There was a decrease in zirconium content in the coating composition from 21.9 to 1.1 at.% when the temperature and duration of induction treatment were increased. Maximum hardness equalled 10.3±0.3 GPa.

In this paper, a review of the two- and multicomponent (Ti, Zr, Ta)-(O, C, N) phase diagrams was presented. The conditions of thermal effect on the studied refractory metals (Ti, Zr, Ta) in the presence of nonmetallic elements (O, C, N) for obtaining oxides, carbides and nitrides were determined. It was shown that in order to obtain refractory ceramic layers (coatings) of the required composition it was necessary to provide the heating above 1000 °C. For this purpose, the treatment with high-frequency currents of metal samples directly in a gaseous atmosphere or in a reaction chamber (container) containing a solid carbon-containing medium (cementing medium) was most effective.

This study presents experimental results of the investigation of the diffusion behavior of commercially pure titanium when interacting with oxygen and hydrogen. To study the gas absorption, electron microscopy combined with energy-dispersive analysis and secondary ion mass spectrometry were used. It was shown that in the course of heat treatment with high-frequency currents in the temperature range from 600 to 1200 °C, an intensive absorption of oxygen by the surface of titanium was observed. At the same time, desorption of hydrogen from the near-surface layer of titanium occurred and there was a double decrease in hydrogen concentration during thermal treatment in this temperature range.

The paper describes a new method for obtaining a permanent connection of titanium with tool steel and subsequent high-temperature treatment with high-frequency currents in the air. As a result of thermal treatment, a hard and wear-resistant layer of titanium dioxide was formed on titanium. The resulting metal oxide ceramic was tested as a coating for metalworking (cutting) tools. After the preliminary tests, the morphology of the wear of the cutting edges was studied and two wear variants were established – abrasion and shearing. The nature of wear depended on the heat treatment modes and the thickness of the solid layer.

We demonstrate that to form a high-intensity THz terajet (field localization) within the graphene monolayer placed at the shadow surface of one wavelength-dimensions dielectric particle with refractive index near 2 the cubic shape is preferable in comparison with spherical one. A spherical particle is more magnetic than electric due to multipole mode distributions. A graphene monolayer was applied for a picosecond timescale modulation of THz wave by controlling of IR radiation for integrated ultrafast all-optical THz modulator. Application of biological objects to the shadow surface of the mesoparticle instead of graphene will allow studying the biophysical aspects of the interaction of the electromagnetic field with such biological objects.

This paper is devoted to the theoretical study of the effect of Nottingham in a composite electron field emission structure with a nanoscale DLC film on a metal blade. The processes of heat release during electron tunneling through the metal- DLC film interface and through the DLC film-vacuum interface are simulated under conditions of localization of an applied external electrostatic field. A comparative analysis of heat generation for two planar structures with a molybdenum blade is carried out - with a DLC film coating and without coating.

Numerical modeling of spectral absorption and scattering properties of structures manufactured as the ordered arrays of plasmon nanoparticles is carried out in this work. The results of numerical 2D simulation of selective heating of an array of plasmon resonant gold nanodiscs irradiated by a CW NIR laser (810 or 1064 nm) are presented. Calculations fit well to experimental data received. We demonstrate the possibility to control the local amplification of a shining laser field in the space between nanodiscs, as well as plasmon resonance absorption of each individual nanodisc. The perspectives of application of such nanostructures for providing of precision dosed-up thermal effects in cells and biological tissues are discussed.

Creatinine (CRN) is the component of human biofluids (urine, blood) which is a clinically important indicator for evaluation of various diseases, e.g., renal (dis)functions. This work is dedicated to application of molecularly imprinted silica gel (MISG) as a CRN-selective sorbent for solid phase extraction to improve SERS based detection of CRN in urine. MISG was prepared using sol-gel process in the presence of a template (CRN) and aluminum ions which served as a doping agent to create recognition sites. Spectrophotometry studies showed that the combination of doping and imprinting improves sorption capacity ~3 times. We found that doping plays a key role and imprinting without doping does not lead to sorption improvement at all. Hydroxylamine stabilized silver nanoparticles were used as SERS substrate and the maximal CRN signal (i.e., analysis sensitivity) was found in alkaline media. Also, addition of alkali leads to dissolution of MISG matrix that was used to release CRN molecules and speed-up of analysis by skipping elution step. SERS results also demonstrate that MISG possesses the maximal sorption in comparison with silica gels fabricated without imprinting and/or doping. Therefore, the final analysis protocol implies solid phase extraction of CRN from a solution with further pH adjusting of the MISG-CRN complex and SERS detection of the released CRN. The protocol testing using model CRN solution and a urine sample demonstrated possibility for CRN detection at physiologically relevant concentrations and significant reduction of SERS background after extraction step.

Carbon nanoparticles (CNPs) attract a lot of interest because of their numerous unique properties. The advantage of photoluminescent CNPs is the simplicity of synthesis and surface modification, photostability and low cytotoxicity. In connection with the variety of methods of synthesis and the possibility of changing the initial materials, it is expedient to study the factors that affect the properties of the obtained particles. Recently, much attention has been paid to CNPs based on citric acid and ethylenediamine. This is due to the fact that such particles have a high quantum yield and can be an alternative of semiconductor quantum dots. In this work, we report the influence of the form of the diamine and the pH of the CNPs solutions on the photoluminescent properties. We also studied the stability of CNPs diluted solutions in time. As a result of the work, we determined that the optimal pH of CNPs solutions are close to neutral, which makes it possible to use the CNPs in biological objects.

Plant-based and animal-based matrices are widely used in various fields, in particular, in food, perfume and drug production. This requires permanent quality monitoring of their composition. The composition complexity of such matrices complicates the usage of traditional spectroscopic methods for their analysis. In the current study we demonstrate how the efficiency of UV-spectroscopy approach can be increased when combined with chemometric algorithms on the example of Aloe Vera and heparin matrices.

Investigation of proteins interactions with luminescent europium complex is interesting for the practical task of sensitive protein detection, as well as to study fundamental problems of peptide-lanthanide interplay. Presented work is devoted to examine the spectroscopic properties of europium complex (europium trinitrate (2,2'-bipyridyl-6,6'- dikarbonilazandiil)tetrakis (methylene) phosphonate) and to study its interaction with human serum albumin using various spectroscopic techniques. This complex has unique optical ability such as high values of the phosphorescence intensity in aqueous solutions, which exceeds the intensity of many other known coordination complexes of rare earth elements.

The results of the experimental research of the change in the absorption spectra of ascorbic acid solutions with the addition of stabilizer NaHCO₃ have been presented. It was shown that L-ascorbic acid is degraded in an aqueous solution, which causes a change in its absorption spectrum. The use of sodium bicarbonate as a stabilizer did not significantly change the absorption spectrum of chemically pure ascorbic acid in the range of 200-300 nm. The obtained results allow to control the concentration and conditions of application of these stabilizers.

Fluorescence induction curves of Tradescantia fluminensis L. leaves acclimated to growth light of different intensities have been studied. Plants grown at low light (LL, 50–125 μmol photons m^-2 s^-1) and high light (875–1000 μmol photons m^-2 s^-1, HL) revealed different patterns of chlorophyll (Chl) a fluorescence. Chl fluorescence was measured by the PAMfluorometry method, using blue actinic light (455 nm, BAL) or red actinic light (630 nm, RAL). In the case of HL samples, non-photochemical quenching (NPQ) of Chl a fluorescence depended on actinic light intensity, but for all that we did not observe any difference between the samples illuminated by BAL or RAL. Otherwise, for leaves grown at LL conditions, we observed that BAL induced markedly higher NPQ than RAL. For both types of samples, photochemical quenching of fluorescence decreased with an increase in the intensity of actinic light, but in most cases was different upon the action of BAL and RAL. After switching the actinic light off, the NPQ level gradually decreased. The residual value of NPQ (qI), registered in the dark 30 min after ceasing AL, was dependent on the illumination pre-history. Maximal level of qI was observed in LL plants illuminated by BAL. The data obtained are discussed in the context of the problem of the protection of plant photosynthetic apparatus against solar stress.

Biomolecular electronic elements attract at present great attention of researchers. The search for the materials suitable for the creation of new devices and study of electrical and dielectric properties of these materials are important problem. This article presets studies of dielectric loss tangent of albumin protein water solution. Measurements of the dependence of dielectric loss tangent on frequency in the range 25–10⁶ Hz were performed. The experimental results showed nonlinear dependences of the dielectric loss tangent on frequency.

Investigations of optical properties of solutions of biomolecules and biomolecular complexes carried out mainly by spectroscopic techniques are presented. The non-linear dependence of the scattered light intensity on sizes of molecular agglomerates is revealed. Possibility to use nonlinear optical properties for creating optoelectronic components is discussed.

Colloidal systems are used in different fields of science and industry. At present, colloidal systems and their properties are being actively studied. The stability of colloidal systems is the main characteristic. For example, stability is hindered by aggregation and sedimentation phenomena, which are driven by the colloid's tendency to reduce surface energy. The technique of electrophoretic light scattering allows us to measure zeta - potential of colloidal systems related to stability of systems. As compared with other methods (Doppler velocimetry, electrophoresis, optical microscopy, Raman spectroscopy), this technique has a short time for analyses, a small volume of the objects to be investigated and cheap equipment. Zeta-potential is used to characterize particle surface charge and to obtain information about their stability and surface interaction with other molecules. In this review, we focus on nanoparticle characterization. In our study, the new techniques for measurement of zeta-potential of colloidal system is realized on the basis of a total internal reflection prism where the free electrophoresis regime is set. The purpose of our work is to compare two types of sample cells and different techniques of measuring electrophoretic mobility and zeta-potential of colloidal systems. The silicon oxide spheres suspended in deionized water with a concentration of 25% and a diameter of 320 nm were used as a test sample. The results obtained in our study demonstrated the applicability of the method for the investigation of liquid solutions, including biological fluids, and a higher sensitivity as compared with standard measurements techniques in bulk measurements.

Current paper presents the results of the chlorine e6 (Ce6) study on 2D and 3D models of FaDu cells culture. The 2D model or monolayer was used for investigation of Ce6 distribution within individual cells and their organelles. The 3D model or multicellular tumor spheroids were used for estimation of cells’ metabolic processes by the investigation of the Ce6 fluorescence distribution within spheroid's layers and Ce6 fluorescence lifetime. It was shown that 3D cell cultures and Сe6 allows estimating the cells’ metabolic processes better than in 2D monolayer cell cultures. Also, this model allows estimating the photodynamic effect depending on the proximity to the surface of different areas inside the heterogeneous 3D structure.

The aim of work was to study the characteristics of uteroplacental blood flow in pregnant rats, tissue oxygenation and the morphological features of the main internal organs (heart, liver, kidneys) of newborns during chronic intrauterine hypoxia. The rats (8 animals) were divided into 2 experimental groups. The first (hypoxia) group was subjected to hypoxia throughout pregnancy (21 days). The second (control) group was not exposed to any effect throughout the pregnancy. On the 20th day of gestation in both groups, a Doppler ultrasound study of uterine-fetal blood flow and measurement of the placenta was performed. Newborn rat pups of the first day of life were subjected to oxygenation degree measurement. After delivery, the number of rats in the litter was counted and their body weight was measured. After the measurements the laboratory animals were withdrawn from the experiments and morphological study of their internal organs was performed. The studies have shown a clear relationship between the characteristics of uterine blood flow and the presence or absence of hypoxia. In chronic hypoxia, there were low rates of arterial blood flow, an increase in the peripheral resistance of uterine vessels. All this indicates the defective formation of the placenta and impaired blood flow with the development of placental insufficiency. It was also found that hypoxia in the antenatal period adversely affects the number and somatometric indicators of newborn rats in the offspring. Histological examination of the tissues of the heart, liver and kidney of newborn rat pups showed signs of impaired blood circulation, dystrophic and necrobiotic changes in the parenchyma.

Different optical techniques are widely used for the characterization of red blood cells (RBC) aggregation. Advantages of these techniques are in their relative simplicity and possibility to analyze a large number or single cells simultaneously without mechanical contact with investigated red blood cells. RBC aggregability refers to the cells' ability to form multicellular aggregates in the presence of different plasma proteins or macromolecules. Opposing forces determine the extent of aggregation by: the repulsive force between the negatively charged cells, the cell-cell adhesion induced by the macromolecules, and the disaggregating flow-induced shear stress. Kinetic and dynamic features of the cells interaction can characterize the RBC aggregation process. In our previous publication, we used de Gennes’ approach that describes macromolecules behavior in the space between two solid surfaces for analysis of the kinetics of rouleaux formation. The present study was undertaken to examine the RBC aggregation in dextran 150 kDa solution, in the light of de Gennes’ model, in a concentrated RBC suspension using the diffuse light scattering technique as well on the single cell level in a highly diluted suspension with pairs of the cells using the optical tweezers. We demonstrated that the kinetics (timing process) and the mechanical features (forces balance characterization) of dextran 150-induced RBC aggregation are not identical according to their contribution to the aggregation process. Optical methods provided handy tools to study the kinetic and dynamic peculiarities of RBCs aggregation and disaggregation, which can be extremely useful for controlling the blood microcirculation especially in cases of hemorheological disorders.

The work is devoted to the determination of the diffusion coefficients of methylene blue (MB) in pure aqueous and 40%-glucose-aqueous solutions in human tooth dentinal sections in vitro using diffuse reflectance optical spectroscopy and the free diffusion model. The determination of the diffusion coefficient of MB in a biological tissue was based on the measurement of the temporal kinetics of changes in the diffuse reflectance spectrum. Obviously, the diffusion rate along the dentinal tubules should be the greatest, close to that in water, taking into account some reduction in speed due to interaction with the walls, since they are filled up with a liquid with a high water content. In addition, the density of the dentinal tubules is large enough, so we can expect that their contribution to the total diffusion will be significant. It was determined that the diffusion coefficientfor 0.001% MB in an aqueous solution is (6.74±1.32)·10⁻⁶ cm² and in 40%-glucose solution is (3.89±0.85)·10⁻⁶ cm²/s.

We performed the transmission-mode terahertz (THz) pulsed spectroscopy of several THz-wave penetration- enhancing agents (PEAs): glycerol, propylene glycol, ethylene glycol, and polyethylene glycol, featuring the molecular weight of 200, 300 and 400. We vacuumized the THz beam path in order to reduce an impact of water vapor on measured data. We reconstructed optical properties and dielectric constants of the abovementioned PEAs in the spectral range of 0.1 to 2.5 THz. We analyzed measured THz optical properties along with the literature data for coefficients of PEAs' diffusion into tissues in order to objectively uncover strength and weaknesses of their use in the immersion optical clearing of tissues at THz frequencies.