This PDF file contains the front matter associated with SPIE Proceedings Volume 11845, including the Title Page, Copyright information, and Table of Contents.

Endogenous fluorescence detection of neoplastic tissues could become a sensitive add-in tool for early and precise detection of different tumours in soft tissues. Endoscopic techniques and fiber-optical fluorescent probes allow achieving all organs and places in human body. New light excitation sources and sensitive detectors with high spectral resolution allow detecting low-intensity autofluorescence or to distinguish signals of specific fluorescent markers accumulated in the tumor cells. The most important moment in the current development of steady-state fluorescence technique for diagnostic applications in oncological practice is to develop appropriate databases with information about fluorescent properties of different types of pathologies for each organ and biological tissue types. One need to estimate the influence of cellular environment and state, presence of different intrinsic chromophores and pigments that could distort the emission signals detected. From diagnostic point of view, information about different tumour sub-types, state of growth, dysplastic and benign forms of lesions has to be accumulated and used for differential analysis during primary clinical observations. In this report will be presented experience on endogenous fluorescent detection based on excitation-emission matrix (EEM) development and synchronous fluorescence spectroscopy (SFS) of lower part gastrointestinal tract tumours. Malignant carcinoma lesions of colon and rectum were detected and differentiated from the normal mucosa in broad spectral range (excitation at 280-440 nm, emission at 300-800 nm) by the autofluorescent properties revealed.

Imaging of slow deformations in biological tissues may contribute to study and reveal many complex processes, such as fluid flow, mechanical stress growth and relaxation, formation of interstitial pores caused by application of external force. Here the new method of strain mapping based on analysis of complex-valued OCT signal for real-time cartilage visualization is presented. Cartilaginous tissue is modified with laser radiation, immersion agent glycerol and on air drying. The evolution of strain caused by the modifying effects is analyzed. For the non-equilibrium diffusion regime, it was shown that the tissue experiences intensive alternate-sign strain with the amplitudes up to 0.4. The extensive dehydration within 1 mm thickness of the tissue and pronounced subsurface swelling are detected. The strains caused by osmotically-induced and on air dehydration are compared.

In a recent article (J. Colloid Interface Sci. 578, 358{365 (2020)), we discussed the effect of Kapitza resistance on the stability and efficiency of photoacoustic conversion from gold nanorods, which we illustrated by means of an experimental model of rough particles exhibiting, with respect to their normal counterpart, larger specific surface area and so faster thermal coupling to their medium. We reported a striking improvement of both parameters, and we predicted more directions to modulate the effective value of Kapitza resistance and pursue technological impact as well as new applications. However, the route to the synthesis of rough gold nanorods involves multiple steps and nonstandard process parameters that might have affected their photostability, and so potentially led to an overestimation of the role of roughness. Here, we challenge our previous conclusions by isolating and testing the role of the most important among these factors, such as a thermal annealing under mild conditions and the deposition of a sacrificial shell of silver for galvanic replacement with gold. By a careful analysis of relevant thresholds, we conclude that both treatments actually exert no to a slight acceleration of the onset of photo-damage to gold nanorods. Therefore, our new findings collectively confirm and even reinforce the attribution of our original results to the office of roughness.

Multiparameter optical non-invasive diagnostics (mOND) combining several methods in a single device is one of the most promising technologies for studying human microcirculatory-tissue systems (MTS). This allows one to obtain highly efficient diagnostic tools for rheumatology, endocrinology, surgery, oncology, neurology, and other areas of medicine, as it is necessary to determine the parameters of the perfusion-metabolic status of tissues. However, there are a number of limitations related to its insufficient methodological and instrumental support. This work is devoted to systematizing of the relationship between the main parameters and states of MTS in various diseases and OND methods, as well as developing a formalized scheme for the synthesis of mOND methods. The aim was to substantiate and develop a methodology for mOND to assess the functional state of the MTS of the human body, and to demonstrate an example of mOND implementation in minimally invasive surgery. The results can be extended to other areas of medicine, for example, to improve these methods in rheumatology, endocrinology, otolaryngology, dermatology, neurology, etc.

One of the promising approaches to the treatment of injured tissue is the application of bioengineering techniques based on the introduction of cells into the damage area. An application of cells alone does not provide a complete replacement of the tissue defect. Therefore, scaffolds are used allowing organization of the cells into a structure, which is capable of the total reproduction of the damaged tissue integrity. Great number of factors, which influence the cell behavior and tissue formation at the injury site when using scaffolds are known. Here, we analyzed the effect of structural heterogeneity of scaffolds on cellular behavior and metabolism. All scaffolds were obtained by two-photon polymerization technic. It was found that colonization of heterogeneous scaffolds was insignificant less than homogeneous ones. However, there were not dead cells on heterogeneous matrix. We found that the level of free and bound NAD(P)H for the cells on the heterogeneous and homogeneous scaffolds was differ. This can indicate a different contribution of glycolysis and oxidative phosphorylation intensity in stem cells seeded on two types of scaffolds.

The experimental study of ultrasonic modes was performed for ex vivo skin samples of white Wistar rats. The ultrasound was provided by a Dynatron 125 US system (Dynatronics, USA) after applying an optical clearing agent aqueousalcohol- fructose (20%-30%-50%) solution to the sample surface. Three different ultrasonic modes were used to found the most effective and fastest optical clearing. The optical coherence tomography system, Spectral Radar OCT System OCP930SR 022 (Thorlabs Inc., USA) with a wavelength of 930 nm, was used for obtaining the quantitative data for effectiveness and rate of skin optical clearing. The best mode had a frequency of 3 MHz and a power of 1.5 W in continuous wave mode for 3 minutes.

The goal of our research was to assess the vascularization degree of tumor to predict the efficiency of plasmonic photothermal therapy (PPT) and photodynamic therapy (PDT) in tumor-bearing rats. Before any treatment, 3D Doppler ultrasound imaging was used for assessment of the vascularization degree of transplanted rat cholangiocarcinoma. For PPT, the gold nanorods with aspect ratio of 4:1, functionalized with thiolated polyethylene glycol, were used. After multiple fractional intravenous (IV) injections in rats with cholangiocarcinoma, the tumours were irradiated through the skin by an 808-nm NIR diode laser at a power density of 2.3 W/cm² for 15 min. For PDT, galactose – Luphthalocyanine, as a photosensitizer, was applied by intratumoural injection, in a dose of 2 mg/kg. Then, tumors were irradiated through the skin by 670 nm-diode laser source with power density 200 mW/cm² applied for 1000 sec in three non-overlapping zones covering whole tumour surface to obtain a total irradiation dose of 200 J/cm² for each lesion. The withdrawal of the animals from the experiment and sampling of tissues for morphological study were performed before and 72 hrs after PPT and PDT. The vascular microdensity in tumors was assessed on histological sections as vessel counts or vessel area per unit of assessed tumor area. It was shown that efficiency of PPT and PDT therapy was mostly due to the sufficient accumulation of photothermosensitizers in the tumor, therefore preliminary assessment of tumor vascularization degree was necessary before starting a therapy.

The paper discusses the experimental stage of developing a device for the non-contact assessment of blood clotting using the method of laser-speckle correlation. The device based on this method will have a number of advantages over existing hemostasis analyzers: it allows the analysis of plasma micro samples, citrated and native blood by a non-contact optical method. The results of experiments with blood plasma, citrate and native blood, aimed at practical development of the method are presented and discussed. It has been shown that the method of laser-speckle correlation is promising for the creation of a new device for assessing blood clotting.

The gene "N" encodes the nucleocapsid structural protein of SARS–CoV-2 virus COVID-19. In the present time, nucleocapsid protein is one of the important targets for the study of both humoral and cellular immune responses to SARS–CoV-2. In this study sequence of the SARS-CoV-2 gene "N", which is encoding the relevant structural protein, has been transformed into the sequence of numbers with purpose to generate gene-based speckles. Differences in the initial nucleotide sequences have been found and characterized by means of virtual laser gene-based speckles (GBspeckles). It has been shown, that at the interference of two SARS–CoV-2 GB-speckle-patterns, two types of interference pictures are forming: quasi-random speckle structure without interference fringes or fringes, modulated by speckles. It has been demonstrated that implication of interference of two GB-speckles, generated on the virus nucleotide sequences, can be considered as a new direction in modern bioinformatics.

The nucleotide sequences of the neuraminidase gene of Highly Pathogenic Avian Influenza Virus (HPAIV) A strains have been transformed into 2D realizations of GB-speckles (Gene-Based speckles). Possibility of differentiation between different HPAIV strains using the analysis of statistical properties of corresponding GB-speckles has been shown.

Chlamydiaceae family is consisted of intracellular bacteria pathogenic for both humans and animals. In this paper the nucleotide sequences of the gene encoding Pgp4 protein, the well-known virulence factor in Chlamydia, have been successfully transformed into the form of the GB-speckles. Strong discrimination was found between the relevant speckle patterns derived from three Chlamydiae spp., namely Chlamydia psittaci, Chlamydia abortus and Chlamydia trachomatis.

GB-speckles (gene-based speckles) have been generated for two nucleotide sequences of the gene GPCR of Lumpy Skin Disease Virus and Sheeppox Virus. Statistical properties of the interfering GB-speckles have been studied. It have been demonstrated that a structure of the interference speckle patterns is very sensitive to the presence of very small differences between the comparing nucleotide sequences. Case of a formation of evident interferential fringes in resulting picture (superposition of two GB-speckle patterns) has been analyzed in details. It has been demonstrated that an application of the GB-speckles, generated on the target virus nucleotide sequences has the great perspectives from viewpoint of modern bioinformatics.

Our previous study has revealed that specific ornithosis antigens extracted from Сhlamydia psittaci (CP) could possess some modulatory activity on the growth of malignant solid tumors in Wistar rats. Here, in the same model we studied dose-dependent dynamics of tumor growth under the influence of CP antigen derived from CP AMK-16 strain, in doses ranged from 0.025 mg/kg to 1.25 mg/kg given as a single subcutaneous injection. Velocity of tumor growth has been estimated by t-LASCA technique.

The paper presents the results of a spectroscopic study of the "colored" water detected in the splash baths in the supralittoral zone of the Alaid Volcano (the Kuril Islands) from 2015 to 2019. The splash baths with magenta, red and red-yellow water located in different parts of the island in various summer seasons. The analysis of fluorescenсе and absorption data of the water samples revealed the presence of a large amount of bacteriochlorophyll a in the water, which is the main photosynthetic pigment of purple sulfur bacteria. The assumption of the presence of cells of microorganisms was confirmed by observations under a microscope. To determine the morphotype of microorganisms the acetonemethanol extracts from the samples were prepared and studied using spectral methods. The characteristic absorption lines of carotenoids and the monomeric form of bacteriochlorophyll identified cells as Thiocystis and Thiorhodococcus morphotypes of purple sulfur bacteria. The regular observation of water samples with microorganisms in the supralittoral zone of the Alaid Volcano leads to the conclusion that the development of the purple phototrophic bacteria is not an accidental event, but a typical phenomenon in this area. The fact that each summer season colored water were found in different places indicates a cyclical changes in living conditions of microorganisms from favorable to unfavorable habitats.

Aquatic humic substances, or chromophoric fraction of dissolved organic matter (СDOM) in natural water have characteristic optical properties. Considerable effort has been devoted to investigate CDOM optical properties and to improve understanding of biogeochemical carbon cycles in the northern regions. However, due to rare observations up to date there is a limited amount of data available on CDOM research in the sub-Arctic zones. This work summarizes the spectral-optical properties of CDOM from several locations along two coasts of the White Sea. The absorption and fluorescence emission spectra with different excitation wavelength were measured for water sampled in August- September 2020 in the expeditions to several locations of the Karelian and Tersky Coasts, differing in geomorphology, hydrology and anthropogenic influence. The fluorescence was found excitation-dependent; we observed the “blue shift” of emission maximum along with rising the excitation wavelength for all studied CDOM samples (surface and deep coastal water). The absorption spectra are similar in shape for all studied CDOM samples, however, absorbance values reflect concentration of humic substances in some samples. In the Lobanikha Bay we did not find the significant difference in deep and surface CDOM, but in the relict lagoon in Eastern Porya Bay the CDOM was concentrated towards bottom. Those findings are important for understanding the mechanisms of the formation of optical properties of natural water with CDOM of various origins.

Environmental monitoring of natural water bodies is important in the Arctic zone for studying their evolution under the influence of climate change and the urbanization processes in the region. In connection with the specific life conditions for anoxygenic phototrophic microorganisms their presence can indicate hydrogen sulfide contamination of the water reservoir and serve as a marker of hydrogen sulfide. This makes the problem of optical diagnostics of phototrophic bacteria very urgent and important. There is a number of spectral methods for determination of chlorophyll-containing microorganisms. The spectral properties of photosynthetic bacterial pigments, bacteriochlorophylls (BChls), are still poorly understood, however. For the first time we applied fluorescence spectra of BChl extracts to receive depth distribution of BChl d in the lake. Fluorescence emission spectra were measured using a Solar CM2203 luminescence spectrometer under excitation at wavelength of 425 nm, corresponding to the BChl d absorption peak. In September 2020 the maximal concentration of BChl d was found at the depth of 2.275 m (16700 mg/m³) in Lake Trekhtzvetnoye. The thickness of the bacterial plate did not exceed 5 cm, and the pigment distribution was found vertically asymmetric. We emphasize that fluorescence quantification of BChl d is more sensitive compared to spectrophotometric one, and it makes possible estimation of ultralow BChl concentrations without water sample pre-concentration.

It is shown that the treatment of potato tubers with growth regulators (the preparations “Epin-Extra”, “Zircon”, “Siliplant”) results in the increase in fluorescent parameter (F_M−F_T)/F_T of plants grown from these tubers, indicating on the increase in the photosynthetic activity of the plants. The treatment of potato seed tubers with growth regulators and also with their mixtures with a fungicide “Maxim KS” contributed to the optimization of a number of physiological indices: it reduced the tubers mass decrease under prolonged storage, the degree of their affection by the diseases, and also the consumption of the nutritious substances. This treatment resulted also in the increase in the subsequent potatoes yield. The high positive correlation was established between the fluorescent parameter (F_M−F_T)/F_T of the leaves, on the one hand, and potatoes yield at various variants of it treatment before storage, - on the other.

The cultures of filamentous fungi in aquatic medium release fluorescent metabolites (FM) with emission spectra that closely match the typical fluorescence bands found for soil extracts and aquatic fluorescent dissolved organic matter (FDOM). FM released from some fungal cultures show as well comparable values of fluorescent quantum yield, the blue shift of emission spectra excited in the UV, and a very close match of ultraviolet–visible absorbance spectral curves related to soil and aquatic FDOM, further strengthening the similarity of fluorophores in those aquatic material. Given the importance of microscopic filamentous fungi in the global carbon cycle, our results indicate that filamentous fungi are likely to be important sources of aquatic and soil FDOM of microbial origin.

NADH is one of the central signalling molecules that serve as a substrate for many vital processes, in particular, is a donor for the electron transport chain in mitochondria. At the same time, mitochondrial activity and the intensity of metabolic processes in the tissues of different brain regions drastically differ. This work aimed to compare the NAD(P)H production rate in the tissues of various brain regions (cortex, cerebellum, hippocampus, brainstem) assessed by the parameters of dynamics of its autofluorescence. We studied acute slices of the rat brain of the corresponding regions. The intensity of NAD(P)H autofluorescence and its rate of production was determined to assess the activity of mitochondria. Whereafter the slices were analysed by histological examination. It has been observed that mitochondrial activity in hippocampal tissues is significantly higher than in other brain regions, which may be associated with more complex cognitive functions of the hippocampus in mammals. The results of this research can help explain the selectivity of hippocampal lesions during ischemic injuries and neurodegenerative diseases.

The paper presents results of the estimation of bioenergetic parameters in acute slices of brain rat by measuring mitochondrial pool and rate of NADH production using fluorescence imaging. NAD+ and NADH play crucial roles in mitochondrial energy metabolism due to their participation in the tricarboxylic acid cycle and in electron transport chain. That is why it is essential to know variability of its content in cells. In the study we used an approach based on the registration of auto-fluorescence of NADH. An experimental setup was designed and assembled for the imaging of the acute brain slices but also capable of measuring brain cell cultures. BDL-SMN-375 laser (Becker&Hickl, Germany) was used to excite fluorescence at the wavelength of 375 nm. The parameters of NADH content in both acute brain slices and cell cultures of midbrain and cortex were estimated. The obtained results can be of interest for better understanding of development of neurodegenerative diseases of mitochondrial disfunction origin.

Skin optical clearing is the method providing the increase of the depth and the contrast of non-invasive optical techniques. Dehydration is one of the possible mechanisms of optical clearing that may lead to reduce in both skin thickness and backscattering. However, the contribution of dehydration of skin to the collimated transmittance spectra is not studied in details. This paper presents the results of such study with rat skin ex vivo. Dehydration of skin sample was provided using a fan with a heater. Throughout the experiment, a warm air flux (~ 36 °C) was directed to the dermal side of each sample. Transmittance spectra were obtained using a system of two optical fibers equipped with collimators in the wavelength range of 400-800 nm. The thickness was measured during dehydration using a micrometer. As a result, it was found that a decrease in the thickness of the skin sample during dehydration led to an increased light transmission through the skin (an 11-fold increase at λ= 700 nm), and, at the same time, to an increase in the light attenuation coefficient μt due to an increase in the concentration of scatterers in the skin per unit volume.

A color coded flow mapping method for ophthalmic applications of optical coherence tomography (OCT) is presented. The described algorithm was developed taking into account the specific changes in the interference signal caused by the characteristics of the biological fluid flow through the scanning plane. A key feature of the algorithm is the multistage analysis of fluctuations in the speckle pattern of OCT-images. Speckle pattern is identified by using the color reverse function, convolution, threshold limitation, morphological digital processing, convex hull generation, gradient based processing and image recoding. The interference signal intensity peaks caused by sharp changes of the optical properties at the boundaries of highly scattering layers (the retina has a multilayered structure) are smoothed out for the specklestructures mapping. The correlation coefficients of the same parts of the sequence of structural OCT-images are calculated not for pixel intensities, but for previously identified speckle pattern. The variance values between nonoverlapping parts of the same structural image are calculated also not for pixel intensities, but for previously identified speckle pattern. Absolute flow velocity quantitative evaluation is made by a standard way, i.e. taking into account the time intervals between acquisition moments of the corresponding parts of the interference signal.

A method for studying atherosclerotic plaques on the walls of large blood vessels is described. The method is based on a study of raw data of intravascular optical coherence tomography (IOCT). Identification of fat constituents, calcium, cholesterol crystals, macrophage clusters, blood clots, etc. within the areas of atherosclerotic lesions of blood vessels is based on the study of two parameters only. The intensity of the A-scan interference signal is the first parameter, and the biomechanical properties (primarily Young's modulus) are the second analyzed parameter. The pulse wave is used as the least traumatic deforming effect. The magnitude of the deforming effect in blood vessels is calculated using averaging of the blood pressure differences. This data is acquired using an invasive pressure probe. Structural IOCT-images corresponding to the moments of systole and diastole are selected from the sequence of raw data. Both IOCT-images are segmented and classified by signal intensity. Primarily, identification of segments is based on reference data of the optical properties of the atherosclerotic plaques’ components. The segments with similar geometrical locations and signal intensity are grouped into pairs. The centroids are calculated for all segments. The absolute displacements of the segments are estimated by the displacements of the centroids. The area of deformation is considered to be equal to the scanning area of the applied intravascular probe. The dimensions of the deformable area for the set of segments of two analyzed images are calculated with respect to the coordinate axes and then averaged. The biomechanical properties of the segments are calculated according to classical formulas and are used to update values of the primary identification of the structural components of atherosclerotic plaques. Information about the geometric characteristics and internal structure of atherosclerotic plaques are used to identify their properties and current stability.

A method for cerebral vessel tissue-like phantom making and a device for the realizing pulsating flows in them are described. The blood vessels are molded together with models of the organs carrying them. A blood vessel phantom is a hollow structure with three-layered walls mimicking its geometry, structure, inhomogeneity of optical and mechanical properties. The model of an organ serves only for fixing the hollow structure of it in anatomically correct position and therefore is homogeneous in texture and properties. The source of information about the geometry of the imitated blood vessel is the results of angiography of a real clinical case. The three-layered structure of phantoms is justified by the anatomical features of real blood vessels (outer layer - adventitia, middle layer - media, inner layer - intima). The three-layered structure is made by layer-by-layer application of a transparent two-component liquid silicone on a wax base. Each layer is distinguished by its thickness and unique concentration of special admixtures (titanium dioxide nanoparticles and absorbing colorant). Mechanical properties of the layers are changed by varying the concentration of the components of the transparent liquid silicone. The phantom is solidified and then heated to remove the wax. Then the phantom of a blood vessel is placed in a mold of a corresponding organ. The mimicking organ is also made from a two-component transparent liquid silicone with special admixtures. Both proximal and distal ends of the hollow structure are connected with fork catheters. A 1% of intralipid solution in water is used to simulate blood flow in the phantom. Streaming velocity control of a blood-mimicking liquid is provided by a syringe pump. Pulsating flow is generated by the controlled twisting of the tube between the pump and the phantom of a blood vessel. A vibration motor is used to change the velocity profile. The described experimental model of a hydrodynamic phantom of a blood vessel is used in combination with intravascular optical coherence tomography for checking compression elastography properties.

The dosing uniformity indicator of the «Papazol» tablets of two manufacturers was evaluated according to the Russian State Pharmacopoeia XIV and by Principal Component Analyis (РСА). The pharmacopoeial method showed that “Papazol” tablets (“Pharmstandart-Leksredstva”) satisfy the requirements for dosage uniformity. “Papazol” tablets (“Irbit Chemical Pharmaceutical Plant”) do not meet the requirements for dosing uniformity. The possibility of the PCA method application for rapid testing of “Papazol” tablets for dosage uniformity was investigated. The results obtained are consistent with the data obtained using the pharmacopoeial direct determination method. The objective of this study was to present the spectrophotometry method coupled with chemometrics approaches as a simple, cost-effective, and accurate for the dosing uniformity indicator testing in pharmaceutical formulation.

In this work, the possibility of using machine learning in the spectral analysis of exhaled breath for early diagnosis of diseases is considered. Experimental setup consists of a quantum cascade laser with a tuning range of 5.4-12.8 μm and Herriot astigmatic gas cell. A shallow convolutional neutral network and principal component analysis is used to identify biomarkers and its mixtures. A minimum detectable concentration for acetone and ethanol at sub-ppm level is obtained for optical path length up to 6 m and signal-to-noise less than 3. It is shown that neural networks in comparison with statistical methods give a lower detection limits for the same signal-to-noise ratio in the measured spectrum.

The paper presents a schematic diagram of the experimental setup human breath analysis using a broadband infrared quantum-cascade laser and a multipass Herriot gas cell. The sensitivity of described experimental setup allows to detect most common biomarkers of various diseases. The experimental spectra for several test substances are measured, threshold concentrations are detected. Statistical numerical methods and deep learning for spectra analysis are considered.

Terahertz (THz) technologies demonstrate significant potential for medical and biological applications. Despite a low penetration depth of THz waves into biological tissues due to the absorption by interstitial water, tissue freezing can be used for overcoming this limitation up to a certain limit. Moreover, application of low temperatures leads to changes of tissue dielectric properties, which yields additional perspectives of THz spectroscopy for study of different states and conditions of tissues, in particular, for observation of their freezing during cryoablation. In this work, the contrast of refractive index featured by unfrozen and frozen adipose and liver ex vivo tissue samples is demonstrated experimentally, along with the ability to detect the freezing depth using THz pulsed spectroscopy.

In this paper the optical properties of the purulent content of the maxillary sinuses were obtained by spectrophotometry. Based on the obtained absorption and reduced scattering coefficients, a numerical simulation by Monte Carlo method was performed to determine the pattern of light scattering passing through the maxillary sinus with purulent contents. The results of the simulation showed that in transillumination methods for the detection of purulent pathological changes, it is more informative to use the radiation sources with 980 nm.

Lugol as an antiseptic dye based on iodine and glycerol is widely used in clinical dentistry to identify areas of tooth demineralization and to detect initial caries. In this work, the kinetic parameters of Lugol (aqueous solution of potassium iodide (0.02 w/w) and glycerol (0.94 w/w)) diffusion in the dentin of a human tooth are determined. A modified Fick's second law, free diffusion model, and diffuse reflectance spectroscopy were used to determine the effective Lugol diffusion coefficient (binary diffusion coefficients of tissue water and iodine/glycerol complex) in the dentin of a human tooth. The quantitative parameters of Lugol's penetration into the dentin of a human tooth and a change in its optical properties should be taken into account when drawing up clinical protocols for the treatment of dental diseases using phototherapy, physiotherapy, photodynamic therapy, laser treatment, etc.

The light source-based medical techniques for brain imaging, diagnosis, and treatment are very common clinical tools. However, applying these techniques is limited due to the high attenuation of light in the scalp and skull. Such optical attenuation reduces the achievable spatial resolution and precludes the visualization of small features such as brain microvessels. The present study aims to clarify the current methods for providing a desired optical access to the brain with good visualization of the microvessels. The strategy involves the use of transparent cranial implants and optical clearing agents to improve the optical access for laser speckle imaging of cerebral microvasculature. In vivo laser speckle imaging experiments of the mouse, cerebral blood vessels showed that the proposed optical access with combined transmittance of the optically cleared scalp overlying the transparent cranial implant increased signal to noise ratio and image resolution, allowing for visualization of microvessels through the transparent implant, which was not possible through the uncleared scalp and intact skull.

Stressful states of the body are accompanied by a hormonal response, including an increase in the level of the hormone cortisol. Due to the fact that cortisol is contained in many biological fluids of the human body, as well as accumulates in some tissues, researchers are attracted to the possibility of determining cortisol by point-of-care methods, which include immunochromatographic analysis. This paper discusses some important practical nuances that need to be taken into account when creating a test strip for detecting cortisol, for example, in human salivary fluid. Keywords: cortisol, gold nanoparticles, stress, saliva, lateral flow immunoassay, test strips. 1. INTRODUCTION

The aim of the study was to assess the effectiveness of the original treatment of patients with psoriasis, including VLOK- 525 and the local impact of pulsed IR NEELIE. Under the supervision of a 264 patients with widespread forms of psoriasis in progresive stage (163 men and 101 women) between the ages of 24 to 63 years old (average age - 41 years), being diagnosted with the disease from 1 to 30 years ago. In the main group the complex treatment included the original laser methods apparatus " LAZMIK VLOK," with the laser head emit KL-VLOK-525-20 for intravenous laser blood irradiation and ML-635-40 for external impact. It was shown that combined laser therapy of patients with a moderate form of psoriasis (10 <PASI<50), including a local effect on psoriatic elements by pulsed red light LIL (635 nm) with a power of 40 W with a pulse repetition rate of up to 10 Hz OOO-VLOK-667 allows effectively the cease of inflammatory changes and lead to a reduction in erythema, infiltration and exfoliation.

The paper presents the investigation of change of optical properties of the rat transplanted cholangiocarcinoma doped with gold nanorods after laser-induced plasmon-resonant photothermal treatment (PPT). 72, 48 and 24 hours before the experiment the animals were injected with the suspension of gold nanorods intravenously. For irradiation a diode laser with wavelength 808 nm was used. After the irradiation the tumors and surrounding tissues were removed and sliced. The samples studied were: skin, subcutaneous connective tissue, tumor capsule, top, center, and bottom part of tumor. Spectra of total transmittance and diffuse reflectance of the samples were measured in the wavelength range 350-2250 nm. Absorption and reduced scattering coefficients of the tumor tissues were calculated with inverse adding-doubling method. The results of the experiment were compared with result of investigation of the control tissues without gold nanorods injection and PPT. A decrease in the absorption coefficient of tumor layers in the water absorption bands was obtained, which indicated tissue dehydration during PPT. A decrease in the reduced scattering coefficient of tumor layers indicated an increase in the size of scatterers and an increase in their ordering. Changes in the optical parameters of the skin and subcutaneous layer were insignificant, which indicated a weak thermal damage.

The possibility of endovenous laser coagulation using Ti-containing optothermal fiber converters (TOTFC) is discussed. Optical and thermal models have been developed to estimate the distribution of radiation and temperature in the vein during endovenous laser coagulation when using TOTFC for 532 nm, 810 nm, 980 nm, 1064 nm, 1310 nm, 1470 nm, 1910 nm and 2100 nm wavelengths. Radiation intensity distributions around the TOTFC and on the vessel wall were obtained and evaluated. The absorbance efficiency of laser energy with different wavelengths for TOTFC has been calculated. As a result of the thermal calculation, for different wavelengths, average laser power from 8 to 15 W with traction speed from 1 to 7 mm/s, the thermodynamics of the blood vessel wall and TOTFC was determined. During endovenous laser coagulation temperature inside TOTFC exceeds 500°C. The optimal combinations of average laser power and titanium-containing converter traction speed are defined for coagulation of the vein wall.

Surface-enhanced Raman scattering tags show promising potential for in vitro and in vivo bioimaging applications due to lack of photobleaching and narrow spectral lines. However, reproducible and controllable growth of nanostructures with a high density of hot-spots is still a challenge. In this work we report on an improved strategy for the synthesis of core/shell Raman tags with a high density of hot-spots from petal-like shell structures and a high-rate immobilization of reporter molecules. The strategy based on simultaneous growth and reporter functionalization of the Au shell around Au nanospheres coated with 4-nitrobenzenethiol. We obtained that the amount of added 4-nitrobenzenethiol controls the structure of the resulted particles. Various types of particles were obtained including gap-enhanced Raman tags (GERTs) with a solid shell, petal-like GERTs, porous Au particles filled with Raman molecules. Optimized petal-like tags (p- GERTs) demonstrate a SERS response 50 times higher than usual gap-enhanced Raman tags, which make them suitable for spectroscopy at the single-particle level. Due to the high SERS response and unique porous structure these nanoparticles have great potential for biomaging and other applications.

Nanotechnology is actively used for diagnosis, treatment and prophylaxis against coronaviruses. To date, methods for producing antibodies and prototypes of vaccines for four types of coronaviruses have been developed. These are: transmissible gastroenteritis coronavirus, avian coronavirus, severe acute respiratory syndrome coronavirus, and SARSCoV-2 coronavirus. Gold nanoparticles can be used as adjuvants to increase the effectiveness of vaccines by stimulating antigen-presenting cells and ensuring controlled antigen release. Thus, gold nanoparticles, which have adjuvant properties, can be an excellent tool in the design of effective vaccines against infectious diseases.

Currently, GERTs tags are widely used nanoparticles in various fields of biosensing and bioimaging. This is due to their high SERS response and depends directly on their structure. Understanding Raman signal dependence on the GERTs structure is a key to creating custom tags with the required SESR response. In this regard, we obtained GERTs tags based on different nanocore and carried out a comparative analysis of their SERS properties. Three types of core were used: nanospheres, nanopolygons, and nanorods. Benzenedithiol-1,4 was used as a Raman reporter. Signal intensity increased in the spheres-polygons-rods series and maximum of SERS enhancement factor was obtained from GERTs based on nanorods of the order of 2E+06.

In this work we present the possibility of using a sensor based on luminescent carbon nanostructures (CNS), which is a good alternative to multi-step methods of determining heavy metal ions and cancerogenic substances. The approach is based on the principles of "green chemistry," effective, simple, fast. As a part of the work, the influence of various synthetic conditions on the CNS sensitivity to the presence of different ions was studied. It was found that sensors based on different polysaccharides are sensitive to the presence of dichromate ions in the solution.

Recently, there has been great interest in the potential use of metal nanoparticles in various fields: physics, medicine, microelectronics, biology, etc. Copper nanoparticles are not inferior in properties to nanoparticles of noble metals, however, they are much cheaper and more accessible. This work shows the preparation of an effective bactericidal composite with copper nanoparticles. Glauconite from the Beloozersk deposit in the Saratov region was used as a matrix for creating the composite. Glauconite can be a stabilizer for air-unstable copper nanoparticles. The glauconite structure has nanoscale porosity, which largely increases the effective sorption surface. The copper nanoparticles obtained by the chemical reduction were immobilized on a glauconite matrix. Sorption of nanoparticles was monitored by spectrophotometry. The bactericidal efficacy of the obtained nanocomposite was investigated in relation to clinical bacterial strains. These studies can be in demand in veterinary medicine, agriculture and medicine, after additional research.

We investigate the possibility of reusing CTAB solutions for repeated synthesis of gold nanorods. Three tasks are solved. The first task is to clean the growth solutions from gold nanorods. The second task is to develop a method using a purified cetyltrimethylammonium bromide solution for repeated synthesis of gold nanorods with the same optical properties as in the initial synthesis. The third task is to test the possibility of management of the optical properties of nanorods for repeated synthesis. The polydispersity of nanorods is estimated by form factor using a mathematical model.

Alloyed quantum dots (QDs) are luminescent semiconductor nanocrystals, which are promising materials in various fields of science and technology, including in bioanalysis. The key requirement for alloyed QDs in polar solutions analysis is hydrophilicity. The modification with dihydrolipoic acid (DHLA) makes it possible to increase the alloyed QDs colloidal stability in a polar medium while retaining the advantages of nanoparticles of this structure, and also allows further electrostatic self-assembly of alloyed QDs with antibodies. The article describes the DHLA-modification of the alloyed QDs composition Cd_xZn_1-xSe_yS_1-y / ZnS using 2-mercaptoethanol (BME) as an additional hydrophilizing agent. The effect of hydrophilization conditions on the following modified properties alloyed QDs was studied: photoluminescence quantum yield (PLQY), width peak at half maximum (FWHM), luminescence peak position, colloidal stability during long-term storage. The search for the optimal ratio of hydrophilizing agents DHLA:BME was carried out, at which the advantages of the biligand shell would be maximally realized. The methods presented in this work make it possible to obtain alloyed QDs with a high PLQY (about 65%) and a long stability period (more than 3 months).

We demonstrate luminescent carbon nanostructures (LCNs) with yellow-orange emission synthesized from citric acid (CA) and urea by hydrothermal treatment. LCNs were treated in water and N,N- dimethylformamide (DMF) at 160° for 6 hours. In this case, an increase of the solvent polarity provides the shifting of the LCNs luminescence to the longer emissive region. The LCNs mixture treated in DMF was fractionated by size-exclusion chromatography. It was obtained 33 fractions with three types of emissive sites at 460 nm (fractions 1-7 and 11-33), 540 nm (fractions 8-13), and 620 nm (fractions 12-33).

Magnetic nanoparticles, such as Superparamagnetic iron Oxide Nanoparticles (Fe₃O₄) are used in this theoretical study. These particles represent a unique nanoplatform with a great potential for the development of drug delivery systems via blood vessels, due to their biocompatibility and stability. The mechanisms of magnetic nanoparticles moving in Newtonian fluid (blood) in a static magnetic field are numerically studied. The equations of motion for particles in the flow are governed by a combination of magnetic equations for the permanent magnet field and the Navier-Stokes equations for fluid. These equations were solved numerically using the COMSOL Multiphysics Modeling Software.

A method of non-coherent video-reflectometry based on acquisition and analysis of image sequences in the backreflection mode under white light illumination is examined to characterize the nucleation stage in a plasticized biodegradable polymer (polylactide). Nucleation in the foamed system “polylactide – supercritical/subcritical carbon dioxide” is provoked by a pressure quenching in the quasi-isothermal mode. The features of image formation are discussed for the cases of birth and growth of the surface and bulk pores in the plasticized polymer.

Nucleation in plasticized polymers as the first stage of temperature- or pressure-mediated synthesis of highly porous polymeric matrices is the key factor affecting the structural properties of synthesized matrices. Accordingly, quantification of growth/collapse processes in the ensembles of pore germs during their evolution is of importance for the characterization and control of the morphological and functional properties of matrices. Additionally, analysis of the growth/collapse kinetics for single pore germs allows for evaluation of the physical-chemical properties (the surface tension, the mass fraction of plasticizing agent in the polymer) depending on the external conditions. In this work, the robust image analysis procedures for quantitative description of the pore evolution on the base of video-reflectometry data are discussed. Experimental results obtained in the case of supercritical/subcritical foaming of polylactides are presented.

Currently, there are various methods allowing the improvement of the physical and mechanical properties of metalworking tools. Gas nitriding is one of the given methods. In this work, the improvement of the physical and mechanical properties of high-speed tool steel products using induction chemical thermal treatment (ICTT) in a nitrogen-containing environment is proposed. As a result of the use of short-term treatment by the ICTT method, the hardness of the surface layer of products reaches at least 17–20 GPa with a layer thickness within 0.8 mm. The proposed method enables the improvement of the functional qualities of metalworking products operating under the conditions of friction with increased contact loads.

Structural and morphological characteristics of plasma-sprayed coatings on a titanium base, using powders of zinc-, magnesium-containing calcium phosphates, were studied by optical and scanning electron microscopy. The coatings consist of deposited particles with a size of 50 - 150 μm. The particles form agglomerates of 200 μm or more. Using such modes of plasma spraying of powders of metal-containing calcium phosphates as: plasma arc current - 300-350 A, spraying distance - 50-100 mm, powder dispersion - up to 90 μm, transport gas consumption - 5-7 l / min, it is possible to form a uniform coating.

Combined materials having a high-strength and wear-resistant work surface are used in the material processing industry. To obtain materials, which can provide high wear resistance indicators, complex technological equipment is required. It is also possible to use materials having a hard base with a protective coating of wear-resistant high-hardness material. Therefore, a method of resistance welding for applying a coating of commercially pure titanium to the surface of highspeed 1.3343 tool steel (analogue of R6M5) and subsequent modification of the titanium surface and the entire assembly by high-temperature induction heating to obtain a wear-resistant oxide coating is considered in this work.

In this work, a numerical simulation of induction vacuum deposition of titanium on hardened steel samples was performed. The rational geometry of the tubular target and the induction heating modes, which ensure the minimum heating of the steel plate, were determined. The main results of simulation experimentally confirmed the possibility of creating conditions for the formation of titanium layers on the surfaces of steel plates.

The parameters that determine the manipulation of nanoparticles depend on the parameters of the illuminating optical field. This leads to a number of fundamental limitations. For example, the power is limited by the incident wavelength. However, there are several ways to work around these limitations. In this article, we demonstrate that the optical power acts on a nanoparticle placed near a hole made in the shadow surface of a dielectric particle of wavelength dimensions and with a refractive index contrast of 1.8 like an optical magnet, and the nanoparticle is moved into the nanohole. Numerical simulations show that light can be trapped inside a nanohole even when the hole size is only λ/100 and therefore the optical magnet can attract nanoparticles at least of the same size. The use of such an optical magnet is of interest primarily for surface cleaning and biomedical applications.

This study presents the results of modeling the process of chemical heat treatment (CHT) of titanium disk-shaped samples located in a container with a carbon-containing medium. The main parameters of the considered process were the inductor current and the geometry of the "inductor – container – sample" system, namely, the number of turns, the height and internal diameter of the inductor at constant values of the height and external diameter of the container for CHT. The operating temperature of the outer surface of the container varied in the range from 1100 °C to 1350 °C, which was achieved at an inductor current from 3.4 kA to 5.0 kA in a narrow frequency range of 88±2 kHz. The obtained plots of the distribution of temperature fields made it possible to assess the heating efficiency of inductors of various designs.

The adaptive Wiener filtering method is considered with application to dynamic estimation of low-coherence interference fringe parameters. Feasibility to determine envelope of low-coherence interferometric signal as well as to assess local phase step of the discrete signal via the evaluated coefficients of the adaptive Wiener filter obtained under criterion of the mean square error minimization with respect to predetermined reference signal is demonstrated. Experimental results of low-coherence interferometric signal processing are presented for applications to non-contact surface profilometry and for evaluating internal micro structure of semitransparent objects.

The analysis of influence of low-intensity electromagnetic field on the processes of self-assembly of core histones H3.2 and H4 was performed. To study the self-organization of histones H3.2 and H4 used the method of wedge dehydration. Image-facies analysis included their qualitative characteristics, as well as the calculation of quantitative indicators, followed by statistical analysis. It was established that UHF-Radiation (1GHz, 0,1 μW/cm², 10 min) significantly modifies the process of self-assembly of core histones H3.2 and H4. Established fact influence of low-intensity electromagnetic field on the process of self-assembly of core histones offers the prospect of further study of the biological effects of this type of radiation.

Microstructured optical fibers (MOF) are a highly efficient support for the design and construction of sensitive and lowcost sensors. Currently, molecular imprinting is one of the promising method of MOF inner surface functionalization. Molecularly imprinted polymers (MIP) can be synthesized at MOF inner surface and intensify the selectivity and efficiency of target molecules sorption. This approach can be the base for selective sorption and detection of target molecules on a single sensor device. This paper describes MOF modification by MIP selective for bovine serum albumin (BSA). Polyaniline was used as matrix MIP polymer and was obtained by chemical oxidate polymerization of aniline in soft acid conditions. MOF transmission spectrum were used for monitoring of bonding between the protein molecules and MIP.