This PDF file contains the front matter associated with SPIE Proceedings Volume 11067, including the Title Page, Copyright information, Table of Contents, Author and Conference Committee lists.

In this paper we applied analysis of multivariate time series for detection of changes in functional relations in brain during observation of educational material. Applied method is based on definition of mutual interdependence of processes and is known as Recurrent Measure of Dependence. In the paper we analyzed multichannel EEG signals obtained during experiments with observation of educational material by human subjects. We applied the method to EEG signals and showed qualitative changes in brain dynamics during educational process in comparison to dynamics of background activity.

In this paper we analyzed possibility for detection of EEG oscillatory patterns related to states of low and high levels of human concentration during perception of visual stimuli with help of artificial neural network. We analyzed different variation of EEG signals combination in order to find optimal one. We performed classification of brain states with perceptron-type artificial neural network and analyzed quality of classification.

In this report we propose an approach based on artificial neural networks for the classification and recognition of various states of the human brain associated with the spatial perception of ambiguous images. Based on the developed numerical methodology and analysis of the experimental multi-channel EEG data, we create and optimize an artificial neural network to ensure the accuracy of the classification of EEG states of the brain in visual perception close to 100%. Different interpretations of ambiguous images produce different oscillatory patterns in the EEG of a person with similar characteristics for each interpretation.

In the present paper we describe methods of assessing the degree of synchronization of multichannel EEG recordings of the human brain during the evaluation of mental tasks. We carry out the experiments involving the alternating trials of mental tasks evaluation with simultaneous registration of electroencephalographic (EEG) data.

In this paper we study speciifc oscillatory patterns of proepileptic activity on EEG signals of WAG/Rij rats. These patterns occur during the development of absence-epilepsy before fully-formed epileptic seizures. In the paper we analyze EEG signals of WAG/Rij rats with continuous wavelet transform to find particular features of proepileptic patterns in time-frequency domain. Then we develop new method for automated detection of proepileptic activity on EEG signals. We analyze results of method's performance and its efficiency.

In this paper, we analyze the inter-layer connectivity of multiplex functional network of the brain, where each layer represent the separate timescale. For this task we conduct the EEG experiments, which involve the solving of Schulte tables, the widespread psycological test. Using the wavelet bicoherence we reconstruct the functional network on various frequency bands of brain activity, that allows us to build multiplex functional network. Using the concept of betweenness centrality we analyze the inter-layer interaction in the brain functional network and reveal the regions, which demonstrate maximal inter-layer activity.

In this paper we numerically simulate a two-layer network of coupled Hodgkin-Huxley neurons for modulating a processing visual perception by the human brain. We investigate the influence of the external stimulus amplitude on the dynamics of second layer neurons. We discover coherent resonance phenomenon in the system: there is an area of external stimulus amplitude when both SNR and characteristic correlation time are maximal. We also analyze the influence of internal noise amplitude on the system dynamics.

Here, we introduce the method based on artificial neural networks (ANNs) for recognition and classification of patterns in electroencephalograms (EEGs) associated with imaginary and real movements of untrained volunteers. In order to get the fastest and the most accurate classification performance of multichannel motor imagery EEG-patterns, we propose our approach to selection of appropriate type, topology, learning algorithm and other parameters of neural network. We considered linear neural network, multilayer perceptron, radial basis function network (RBFN) and support vector machine. We revealed that appropriate quality of recognition can be obtained by using particular groups of electrodes according to extended international 10−10 system. Besides, pre-processing of EEGs by low-pass filter can significantly increase the classification performance. We developed mathematical model based on ANN for classification of EEG patterns corresponding to imaginary or real movements, which demonstrated high efficiency for untrained subjects. Achieved recognition accuracy of movements was up to 90−95% for group of subjects. RBFN demonstrated more accurate classification performance in both cases. Pre-filtering of input data using low-pass filter significantly increases recognition accuracy on 10−20% in average, and the low-pass filter with cutoff frequency 4 Hz shows the best results. It was revealed that using different sets of electrodes placed on different brain areas and consisted of 6-12 channels, one can achieve close to maximal classification accuracy. It is convenient to use electrodes on frontal and temporal lobes for real movements, and several sets containing 6-9 electrodes — in case with imagery movements.

In the present paper we describe that the synchronization of various patterns of brain activity in the process of locomotor activity differs for groups of conditionally healthy subjects and patients. We study the difference between healthy subjects, patients in post-stroke dynamics and patients with chronic hypertension. Conditionally healthy individuals demonstrate the normal (typical) character of brain activity when moving with the hand. Impaired blood supply to the brain, apparently, leads to a stationary increase in the frequency of oscillatory activity recorded on the EEG, which is observed for patients with both background recording and physical activity. Patients with paresis caused by cerebral hemorrhages and disorders of the corresponding mechanisms in the acute period after stroke recovery demonstrate an uncompensated destruction of the mechanism for controlling the motor functions of the hands, leading to an increase in low-frequency activity patterns during attempts to make a movement. Patients with arterial hypertension and cerebral ischemic disease in the course of the motor act show an increase in the amplitude of the patterns in the frequency range (8 - 12 Hz). The analyses of EEG data is based on wavelet math methods. The study of the level of EEG activity changes may serve as some diagnostic criterion for assessing changes in brain activity during the development of degenerative processes.

In the present paper, a sample test "fist-rib"/"palm-fist" was considered for the analysis of the totality of brain and muscle activity. A group of 20 people, unpaid volunteers, took part in the experimental neurophysiological work. To analyze the recorded signals of brain activity, we used wavelet mathematics and developed algorithms based on the calculation of skeletons. We found a significant difference in EEG activity for the subjects, objectively shared by health condition. Further development of the proposed method will be aimed at creating a device of diagnostic type, close to real-time operation.

The work is devoted to describe our automated technique of tumour and neoplasm volume assessment on brain MRI. First we proposed adaptive processing of dynamic local surroundings by estimating of local entropy. Secondly, the investigation of volume assessments directly is ground on the proposition to check extent of interdependency between adjacent slices. The overall approach uses double-criterion principle. The first one estimates cross correlation, the second one is based on Max-dependency principle. Obtained results prove consistency of the implemented approaches.

A process of health-saving accompaniment individualization implies constant monitoring of the functional state. There is a universal method of instrumental evaluation and prediction of the human adaptive state, considering its individual, genetically determined structural and functional characteristics. It is a method of LGNRO assessment. LGNRO is for a level of general nonspecific reactivity of an organism, qualitatively and quantitatively characterizing a level of individual sensitivity and reactivity to various exogenous effects. The biometric analysis of the organism’s nociceptive characteristics has revealed the general biological character of the normal distribution of the thermal sensitivity threshold (TST) in human populations and laboratory animals. The possibility of a rapid assessment of LGNRO by means of TST is justified. Morphofunctional characteristics of individual brain structures and their role in the formation of LGNRO have been determined. The genetic determinancy of phenotypic manifestations of LGNRO has been proved. Based on the results of experimental studies, an algorithm and a corresponding computer program have been developed that provides system-specific personalized monitoring of human health status in real time.

We discuss the entrainment phenomena in the cerebral and peripheral blood flow in rats. Using the laser speckle contrast imaging and the wavelet-based multifractal analysis, we reveal the adjustment of the numerical measures characterizing the blood flow dynamics at the pre-stroke stage. We detect the adjustment of correlation properties, which is observed in more than 80% of laboratory animals, and suggest a hypothesis about a pathological synchronization.

We discuss the ability to recognize the electrical activity of the brain associated with the movements of the hands/legs and imagination of such movements. Conducting experiments with a group of untrained volunteers, we show that real and imaginary movements are clearly detected using the scaling exponent of the detrended fluctuation analysis for the majority of EEG channels (usually 28-31 out of 33). Although this ability is shown regardless of the type of movements, the case of leg movements provided a slightly higher recognition results. This conclusion is supported by numerical estimations based on two quantitative measures.

This review highlights two opposing concepts of lymphatics and glymphatics, which are used to explain the drainage and cleansing functions of the brain. "Stumbling blocks" in two concepts and ways of compromise between them are discussed.

The spectral properties and synchronization of low-frequency (LF) oscillations during the tilt test were studied for the heart rate variability (HRV) and the finger photoplethysmogram (PPG) of healthy subjects. Dynamics of the LF oscillations in the PPG and synchronization strength between the HRV and the PPG were found to be inhomogeneous among healthy subjects, which suggest existence of individual differences in characteristics of adaptive reactions of the cardiovascular autonomic control.

Phase synchronization between breath rate, heart rate variability, blood flow and blood volume oscillations were studied from healthy volunteers at rest. The degree of synchronization between the phases of the analyzed signals was estimated from the value of the wavelet phase coherence. High phase synchronization between blood perfusion and blood volume oscillations in a wide frequency range from 0.0095 to 0.1 Hz and at the frequency of heart rate (~ 1 Hz) was obtained. Significant phase synchronization were demonstrated between heart rate variability both skin blood flow oscillations and blood volume ones at the frequency of endothelial (~ 0.01 Hz) and myogenic (~ 0.1 Hz) activities. It was revealed high phase synchronization at the respiratory frequency (~ 0.3 Hz) for blood volume oscillations and low synchronization for blood flow ones. Also there are differences of phase synchronization of blood volume and blood flow oscillations with respiratory rate at the breath frequency. It was obtained high phase synchronization at this frequency for blood volume oscillations and low synchronization for oscillations of skin microvasculature. We assume that the results obtained can form the basis of new diagnostic criteria for assessing the state of the cardiovascular system in pathologies.

We present a composite model of astrocytic Ca²⁺ dynamics, which includes both IP₃-mediated release from intracellular Ca²⁺ stores and bidirectional exchange through the plasma membrane, mediated by the Na⁺/Ca²⁺- exchanger (NCX). The NCX kinetic model is formulated in the Hodgkin/Huxley formalism, taking into account the glutamate transporter-mediated increase in Na+ during synaptic activity and Na⁺- and Ca²⁺-dependent regulation. We define main dynamic regimes and transitions in a point model, describing dynamics in an individual astrocyte segment. We demonstrate NCX-based modulation of store-mediated calcium oscillations (amplitude, frequency and amplitude-frequency), analyze and compare calcium dynamics in models with and without allosteric regulation of NCX by intracellular ions.

Gastric cancer often appears without preliminary symptoms that could be detected and recognized at early stages. Its diagnostic is sometime provided based on photodynamic techniques, although the latter are restricted by quite poor tumor selectivity. Due to this, additional experimental and data processing tools are required to improve diagnostic abilities. In this study we analyze how complexity measures can detect early changes in the normal gastric microcirculation. We apply a recently developed approach based on the multiscale entropy and show that the estimated measures of SampEn related to distinct ranges of scales enable the detection of early gastric cancer that is in accordance with the results of histological analysis.

The rezazurin assay for screening of bacterial growth remains the most popular method for express diagnostic tests. It is based on the change of colour and uorescence properties of the respective dye due to bacterial breathing but its conventional quantitative practical implementation requires a relative expensive and cumbersome spectrophotometric equipment. As an alternative approach, we propose to shift a focus from hardware to software. Preliminary results announced in this work show that the processing RGB colour channels for simple photographic images of resazurin assay plates with mycobacterium tuberculosis provides an opportunity to reconstruct the target growth curve with an accuracy comparable with results obtained using the conventional photometric uorescence curves.

The paper demonstrates the importance of neural networks, which are successfully used in various fields. Artificial neural networks demonstrate a large number of brain properties. They are trained on the basis of experience, generalize previous precedents to new cases and extract significant properties from incoming information which contains excessive data. Technically, training is to find coefficients of connections between neurons. In the process of learning, a neural network is able to detect complex dependencies between input and output data, and also perform generalization. As a result, the analysis showed that, on average, the neural network made 50% of forecasts.

Dimension of an inertial manifold for a chaotic attractor of spatially distributed system is estimated using autoencoder neural network. The inertial manifold is a low dimensional manifold where the chaotic attractor is embedded. The autoencoder maps system state vectors onto themselves letting them pass through an inner state with a reduced dimension. The training processes of the autoencoder is shown to depend dramatically on the reduced dimension: a learning curve saturates when the dimension is too small and decays if it is sufficient for a lossless information transfer. The smallest sufficient value is considered as a dimension of the inertial manifold, and the autoencoder implements a mapping onto the inertial manifold and back. The correctness of the computed dimension is confirmed by its remarkable coincidence with the one obtained as a number of covariant Lyapunov vectors with vanishing pairwise angles. These vectors are called physical modes. Unlike never having zero angles residual ones they are known to span a tangent subspace for the inertial manifold.

The paper studies the ability of neural networks to identify relations between different parameters that makes it possible to express massive data more compactly, providing the data blocks are closely connected to each other. Application of bioinformatics methods allowed to predict a positive effect of different chemical compounds on plants growth which is from 87.5% to 88%.

In this paper we study numerically a general mechanism of realizing solitary state modes by analyzing the dynamics of one-dimensional ensembles of nonlocally coupled Henon and Lozi maps. It is shown that the main reason of appearing the solitary state regimes consists in the emergence of bistability in individual oscillators of the ensemble. The bistability can arise due to the nonlocal coupling between the ensemble elements, which plays the role of an external force. The numerical findings are illustrated by the construction of basins of attraction of the emerging attractors and their phase portraits in the bistability regime of ensemble elements.

A new method of photoplethysmogram analysis for complex assessment of natural fluctuations of pulse blood filling and tone of peripheral arteries based on the results of long-term photoplethysmographic monitoring of peripheral volumetric pulse is proposed. The method is based on finding the variational, statistical and spectral indicators of the relative amplitude characteristics of the photoplethysmogram. Standard algorithms of variational, statistical and spectral analysis are used to realize the method. The method can be used for the analysis of disorders of regulation of regional vascular pulse blood filling, tone arteries of small diameter, as well as conditions of regional venous return of blood to the heart.

In this paper we study the dynamics of a multi-layer network composed of identical layers of non-locally coupled Kuramoto-Sakaguchi phase oscillators. Throughout the intensive numerical study we consider three-layer multiplex network and reveal conditions for a specific form of multi-layer network behavior, the macroscopic chimera-like state. It represents an excitation of different spatiotemporal patterns in initially identical layers of multiplex network under their interaction. Also, we show that transition to such macroscopic chimera patterns can be achieved not only variation of phase shift, but according to introduction of heterogeneity of network elements.

Bioinformation data capturing and preprocessing for molecular modelling is exceptionally time-consuming task. Researcher forced to use inconsistent instruments, which are generate vast amounts of diverse-structured data. Here we propose an integrated instrument automating the stage of data pre-processing for molecular docking – searching of protein receptors, their spatial structures and suitable ligands. The algorithm automatically finds all the synonymic constructs of original query, requesting specified biological databases, populating the list of receptor’s and their ligands’ PDB-identifiers and converts them to AutoDock format (PDBQT). The data sources are open-access specialized biological databases – UniProtKB, Protein Data Bank (PDB) and ZINC15. The virtual screening algorithm implemented using the Python 2.7.9 programming language with several plug-in modules. The result is the data preparation tool for further use in AutoDock-family docking software. The tool has two variants of user interface – desktop application and chatbot for the Telegram messenger.

In the present paper we study the spatial distribution of non-invasive electromyographic signals on the front surface of a human hand arm during movement in the elbow joint. We describe experimental work and mathematical processing of registered signals massive. Statistical processing of signals from the biceps showed that the excitation in muscle tissue with similar movements such as ballistic contraction spreads through the muscle, mostly in a linear fashion. However, there is a random component, which, as expected, is associated with the mechanisms of physiological resistance to muscle fatigue. The hypothesis is confirmed by the increase in the level of the random component for the trained subjects (athletes).

In this paper we propose a model of the spatially distributed network based on the spatially correlated preferential attachments. Nodes in the spatially distributed networks of the real word, such as various urban or biological networks, aren't establishing randomly: the probability of emergence of new nodes is higher in the area of already existing ones. In this work we unite two principles of the real network modeling: the correlated percolation model and preferential attachment. To regulate spatial limitations of the network, we use density gradient, which determines the decrease of the probability of the connection emergence between two nodes with increase of the distance between them. We also consider the consistency of our results in the context of the real-world system modeling.

Analysis of the influence of low-intensity electromagnetic field on the processes of self-assembly of the lincer histone H1 was performed. To study used a wedge dehydration method. Image-analysis of facies included their qualitative characteristics and calculation of quantitative parameters with subsequent statistical processing. It was established that UHF-Radiation (1GHz, 0,1 μW/cm² , 10 min) significantly modifies the process of self-organization of lincer histone, which determines the possibility of the involvement of the genetic apparatus of the cell in the effects of this type of radiation on biological objects.

The Raman spectra of five samples of sunflower seed oil and five samples of cold-pressed olive oil of various brands are recorded in the range of 500–2000 cm^–1. Within the framework of the B3LYP/631G(d)/6-31G(d,p)/6-31+G(d,p)/6- 311G(d)/6-311G(d, p)/6-311+G(d,p) methods, the structural models of eight fatty acids (oleic, linoleic, palmitic, stearic, α-linolenic, arachidonic, eicosapentaenoic, and docosahexaenoic) are constructed, and also within the framework of the B3LYP/6-31G(d) method, the structural models of triglycerides of the first four of the above acids are obtained. The vibrational wavenumbers and intensities in the IR and Raman spectra are calculated. The Raman spectra of olive oil and sunflower seed oil were simulated by using the supermolecular approach. We investigated the dependence of the relative intensity of the vibrational bands ν_exp = 1660 and 1445 cm^–1 on the concentration of triglycerides in oils of oleic and linoleic acids and the dependence of the intensity of these bands on the degree of saturation of fatty acids. Experimental and empirical dependences are constructed to estimate the relative concentration of triglycerides of oleic and linoleic acids in a mixture of olive oil and sunflower seed oil. The applicability of the density functional theory together with the vibrational spectroscopy for the identification of mixtures of vegetable oils is discussed.

While vasoreactivity of an individual blood vessel is quite well studied, much less in known about stimulustriggered behavior of microcirculatory networks in situ. The available experimental data on topic suggest that the response pattern of the network, being the coordinated change of flow through the group of vessel, asa well as adjusment of their diameters, ofthen can be found inconsistent with what is expected from ”system of elastic tubes”. Physiologically, this is due to autoregulation of vascular tone by means of number of pathways, mediated by cells that form two main cellular layers - the endothelial cells and the vascular smooth muscle cells. Since it is still not easy to measure simulteneously bothe the flow/diameter and the degree of activation of smooth muscle cells, the mathematical modeling study on topic is very suitable. In this work we present the results of modeling study performed on the set of 20 different variants of 14-vessels vascular tree. Our results show three distinctive stages of vascular response to the abrupt change of conditions (occlusion of one of vessels).

Purpose. The aim of the paper is to evaluate skin microcirculation in patients with lower extremity PAD before and after conservative therapy and endovascular revascularization by originally developed technique of wavelet analyses of skin temperature together with biochemical markers of endothelial dysfunction. Methods. The study included 17 healthy (44-61 years) and 38 pathological subjects (58-75 years). Patients with PAD were divided into four groups according to the stage of chronic limb ischemia. The study protocol contained biochemical and instrumental methods for the assessment of the functional state of the microcirculation. Results. Significant differences in biochemical and instrumental markers of endothelial dysfunction were observed in the pathological group in comparison with the control group. Examination of patients with PAD two weeks after treatment showed that the levels of inflammation and endothelial dysfunction markers, namely homocysteine, von Willebrand factor and endothelin, became lower. Conclusion. The results of the wavelet analysis of skin temperature applied together with the local heating test indicated the adequate responses of the microcirculation system to physiological stimuli. The outcome of medical PAD treatment is improvement of the microcirculatory function and specific biochemical markers of endothelial function.

Here in ex vivo (confocal imaging) and in vivo (optical coherent tomography) experiments on adult mice, we clearly demonstrate that the meningeal lymphatic drainage is an important mechanism for the brain clearing that might be also pathway for the brain clearing from metabolites and waste products that requests further detailed studies. Photodynamic effects stimulate the meningeal/cervical drainage opening new ideas for development of novel methods of activation of brain clearing that might be progressive strategies in therapy of neurovegetative diseases.

Spreading vascular reactions are mediated by electrical signals that are transmitted through the endothelial layer of blood vessels. The contraction of a vessel as a whole is impossible without the coordinated work of the smooth muscle cells of its wall, the study of the mechanisms and characteristics of their interconnection is important for understanding how their synchronized behavior is formed. In our work, we propose and investigate a mathematical model that focuses on taking into account the peculiarities of the interposition of endothelial cells and smooth muscle cells.

A method for intravital light sheet microscopy of blood vessels of mouse brain cortex is proposed. The use of tilted microscope lens mount and long working distance of microscope lens ensure high contrast images in both scattered light and fluorescence modes without immersion. Fluctuations of laser speckles related with the blood flow has been observed in scattered mode. In fluorescence mode distribution of Evans Blue dye over blood vessel cross-section was visualized.

Fluorescent methods are widely used in studies of the physiology of the brain in general, and in the analysis of the degree of permeability of the blood-brain barrier (BBB) in particular. As recent experimental data show, the spatial patterns of the BBB opening, on the one hand, observed for the whole brain, and on the other, they can be highly localized if one track their from the very beginning. We consider the issues related to image analysis from the point of view of the classification of flowrescent objects, and also propose a technology for simulating BBB leakage based on layer-by-layer modeling of the diffusion process in a heterogeneous spatial template created directly from experimental data.

In our experiments on rats we performed visualization of brain clearing from substances injected into the brain parenchyma using optical coherent tomography and fluorescence microscopy. Our results uncovered that the meningeal lymphatic system play an important role in the brain clearing processes, where the deep cervical lymph node is the first anatomical station of cerebral fluid exist from the brain. These data shed light on the novel mechanisms underlying drainage and clearing function of the brain.

While vasoreactivity of an individual blood vessel is quite well studied, much less in known about stimulustriggered behavior of microcirculatory networks in situ . the available experimental data on topic suggest that the response pattern of the network, being the coordinated change of flow through the group of vessel, asa well as adjusment of their diameters, ofthen can be found inconsistent with what is expected from ”system of elastic tubes”. Physiologically, this is because of autoregulation of vascular tone by means of number of pathways, mediated by cells that form two main cellular layers - the endothelial cells and the vascular smooth muscle cells. Since it is still not easy to measure simulteneously bothe the flow/ diameter and the degree of activation of smooth muscle cells, the mathematical modeling study on topic is very suitable. In this work we present the results of modeling study performed on the set of 20 different variants of 14-vessels vascular tree. Our results show three distinctive stages of vascular response to the abrupt change of conditions (occlusion of one of vessels).

Spontaneous contractile activity is the most important property of small lymphatic vessels since it ensures the fulfillment of their main function - the propulsion of lymph in the direction from the lymphatic capillaries to the lymph nodes. Experimental research and diagnostic assessment of the state of the contractile mechanisms of the structural element of the lymphatic vessel - lymphangion - require, among other things, reliable non-destructive methods to start its contraction cycle at the will of the researcher. In this paper, we propose to use as a tool a highly localized laser radiation focused on the cells of the vascular wall of the lymphangion. We implement this method using laser with a wavelength of 405 nm focused to a spot with a diameter of 10-14 micrometres. The obtained results show a reliable and reproducible response of the lymphangion in the form of a single contraction or their sequence. We also compare the characteristics of such induced contractions with a case of spontaneous activity.

The paper presents theoretical study of biomagnetic fluid (such as blood) flow through a tube under magnetic external field. In this work, we consider blood as a conducting and magnetic fluid that is Newtonian and incompressible. The motion of blood in a tube is described by Navier Stokes and continuity equations. The magnetic field effect on a limit region from the tube, where behavior of blood stream is changed. In dependence of the distance from the field localization, the concentration of magnetic cells of blood is changed, and their velocity shape is different from the original one (parabolic form).

This work is very important for many biomedical applications and bioengineering such as magnetic resonance imaging (MRI), magnetic drug delivery and targeting, magnetic separation and hyperthermic treatments.

The most common protocol for the synthesis of Au nanospheres is the reduction of gold salts by sodium citrate. However, the particles obtained by this method are not quite perfectly spherical and their optical and physical properties suffer from polydispersity and nonuniformity. In this work, we synthesized sets of quasispherical Au nanoparticles with sizes from 20 to 70 nm by citrate-based methods as well as single-crystal Au nanospheres with uniform diameters ranging from 20 to 130 nm. Particles were characterized by TEM, UV-VIS and Dynamic Light Scattering (DLS). We found that the extinction spectra of monodisperse Au nanospheres are equal to those calculated by using Mie theory (both in the position and width of the plasmonic band). The deviation of shape from a sphere that is typical of citratestabilized nanoparticles leads to a significant departure of the optical properties from those predicted by Mie theory. The non-sphericity of these particles also affects the measurement of their size by DLS. In particular, citrate-stabilized nanoparticles display a bimodal size distribution associated to rotational diffusion.

We demonstrate an effective one-pot synthesis of blight-yellow carbon nanoparticles (CNPs) with the photoluminescent (PL) maxima at the area around 600 nm. Hydrothermal synthesis was used as fast and cheap way for one-step CNPs synthesis and modification. Sodium dextran sulfate (DSS) was used as the main precursor for the synthesis; polyethylene glycol based polymer (Jeffamine) and concentrated phosphoric acid were considered as surface passivation agents. The synthesized CNPs have typical for CNPs excitation-dependent PL.

The widespread use of SERS for bioimaging led to the development of the novel types of labels called SERS tags. SERS tags based on a metal core with adsorbed Raman reporters and coated with one or more metal shells are called nanomatryoshkas. In this work we investigated nanomatryoshkas based on gold nanorods coated by 4-nitrobenzenethiol Raman reporter molecules with gold and silver shell (AuNRs@NBT@Au and AuNRs@NBT@Ag, respectively). By changing the conditions of synthesis we can regulate the presence or absence of a gap inside the gold nanomatryoshkas. Moreover, it was found that for these particles the SERS enhancement factor does not depend on the presence of a gap, for both cases enhancement factor is about 4×10⁵. For nanomatryoshkas with a silver shell, it was found that the absence of a visible gap is a feature of these particles, in good agreement with the literature data.

Encapsulation of various nanoparticles in nanofibers has become one of the most interesting topics in the field of electrospinning and SERS. Literature review shows that several main approaches can be distinguished for the preparation of electrospun nanofibers with embedded metal nanostructures. However, there is no information about the comparison of various methods of metal nanoparticles introduction into nanofiber-based SERS-platforms. Three main approaches were used here for preparation of SERS-platforms based on electrospun nanofibers with embedded silver nanoparticles: synthesis of metal nanostructures inside fibers prepared with incorporated precursor, metal nanostructures synthesis via their nucleation in prepared nanofibers and sorption of metal nanostructures onto ready-made nanofibers. SERS-platforms based on polyacrylonitrile nanofibers containing various concentrations of Ag nanoparticles were obtained using techniques described above and tested.

The Yb³⁺-Tm³⁺-doped NaGdF₄ upconversion nanoparticles were studied as contactless nanothermometers for the first biological tissue transparency window under 980 nm excitation. The single hexagonal phase NaGdF₄:Yb³⁺-Tm³⁺ nanoparticles were synthesized by solvothermal technique. The influence of dopants concentration and pumping power density on thermal sensitivity and temperature resolution of obtained nanoparticles was analyzed. It was shown, that an increase of Yb³⁺ doping concentration leads to a strong increase in near-infrared Tm³⁺ luminescence intensity, which corresponds to transitions ³F₂-³H₆, ³F₃-³H₆, ³H₄-³H₆ and could be used for thermometry. The measured efficiency of upconversion luminescence for 80% of Yb³⁺ and 2% of Tm³⁺ doped nanoparticles was 5.0% compared to 0.2% efficiency for 30% of Yb³⁺ and 0.5% of Tm³⁺ doped nanoparticles. Laser induced heating of synthesized nanoparticles with ratiometric temperature measurement was studied. The increase of pumping power density negatively affected the sensitivity, but increased the accuracy of measurement due to the increased near-infrared luminescence. In addition, the comparison of different wavelengths for ratiometric thermal calibration was performed. It was shown, that the use of 680-720 nm luminescence peak to 730-750 nm valley intensity ratio for thermometry promotes significant enhancement of thermal sensitivity and temperature resolution. Thermal sensitivity of 4%∙C^-1 and temperature resolution of 0.6˚C in 30-36˚C region were obtained for NaGdF₄ nanoparticles doped with 80% of Yb³⁺ and 2% of Tm³⁺.

Nowadays semiconductor quantum dots (QDs) is a popular luminescent material for different kinds of bioapplications. Core-shell CdSe/ZnS QDs obtained by the high-temperature synthesis are traditional luminescent nanocrystals with high quantum yield and narrow emission peak. But this type of QDs must be hydrophilized before their use in a water or biological environment. The goal of our work was the comparison of hydrophilized QDs properties, obtained from one initial sample using two different hydrophilization methods. Core-shell type QDs with CdSe/ZnS semiconductors composition was synthesized and hydrophilized by two ligand exchange methods: silanization and coating with dihydrolipoic acid (DHLA). Quantum yield, size and colloidal stability of the nanoparticles obtained via both methods were investigated. The collected data allows making the conclusions about perspectives to use the described methods in different bioapplications.

Polydopamine-coated Au nanorods (AuNRs) have attracted a great interest for various biomedical applications. Polydopamine (PDA) is a light absorbing biopolymer with nonzero imaginary part of the refractive index, which exerts a significant effect on the optical properties of PDA-coated AuNRs. In this paper, we study the changes in plasmonic properties of AuNRs after PDA coating. We observed that the longitudinal plasmon resonance decreases while the transversal one increases. To confirm the experimental observations, we performed theoretical simulations of the extinction and scattering spectra for AuNRs with different geometrical properties, PDA shell thickness and refractive index. The loss of plasmonic peak intensity becomes higher as the axial ratio of the AuNRs or the imaginary part of the refractive index of PDA increase.

The paper is devoted to the study of the photoluminescent properties of lanthanide complexes in aqueous suspensions, as well as the mechanisms of the mutual influence of nanocomplexes and the environment on the properties of each other.

We demonstrate a one-pot synthesis of CdSeZnS/ZnS alloyed blue (482 nm) and green (526 nm) quantum dots in organic solvents. During the formation of core/shell quantum dots (QDs), a blue-shift was observed after coating with ZnS shell. A wavelength tuning of alloyed QDs emission is obtained by the different ratios of Se-precursor in the cores. Silica surface was formed to make water-soluble alloyed QDs. The alloyed QDs were characterized by absorbance and photoluminescence (PL) spectroscopy and PL quantum yield.

In the article for the first time the properties of nanodiamond complexes with dexamethasone obtained by two different approaches - attachment of the drug to the surface of nanodiamond and to the nanodiamond, covered by silica layer – were compared. It was found that the synthesized nanocomposite ND@silica@Dex is able to retain a greater amount of drug and allows achieving prolonged release of dexamethasone. These properties of the complexes ND@silica@Dex provide prospects for their use as drug carries.

In this article we report an effective hydrothermal synthesis of bright-emissive nanoparticles from citric acid and ethylenediamine. Also, we demonstrate methods for separation of carbon nanoparticles such as high speed centrifugation and size-exclusion liquid chromatography. These nanoparticles due to their high quantum yield can be used as markers for biological tissues, liquids and cells.

Herein we present a proof-of concept study of 2-D plasmonic nanoparticles layering strategy. Our approach is based on polyvinylpyridine activation of the substrate surfaces followed by centrifuge-based sedimentation of nanoparticles. The developed platform is rather simple, reusable, and non-toxic for adherent cells, which can be realized for multiple-types plasmonic particles of tunable surface density and used for various biomedical applications, such as cell optoporation, bioimaging, SERS etc.

In this work, the fluorescence quenching of two types of bioactive molecules – of the protein lysozyme and of the drug doxorubicin – by carboxylated detonation nanodiamonds in the result of their interaction has been studied. It was demonstrated that nanodiamonds effectively quench the fluorescence of lysozyme and doxorubicin but by different mechanisms. It was found that the fluorescence quenching of lysozyme by nanodiamonds is caused only by a static type of quenching while the fluorescence quenching of doxorubicin by nanodiamonds is caused by both static and dynamic types of quenching. We propose a hypothesis that the surface groups of nanodiamonds are the quenchers of the fluorescence and the variety of surface groups with which a fluorescent molecule interacts determines the fluorescence quenching mechanism. The accounting of our results will provide the insight in the nanodiamonds’ visualization as well as the possible way to track the loading and subsequent unloading of drugs from the nanodiamonds’ surface.

In this paper, we show a low temperature normal pressure synthesis of a blue emissive organic fluorophore. The organic fluorophore molecule - 1, 2, 3, 5-tetrahydro-5-oxo-imidazo [1, 2-a] pyridine-7-carboxylic acid (IPCA) - consists of derivatives of imidazole and benzoic rings with a carboxylic group. The molecule has a strong emission maximum at around 450 nm when excitation of 350 nm us used and is correlated with PL spectra of carbon nanoparticles. The quantum yield was found to be relatively high: around 55%. IPCA luminescent properties are similar to the reported for some carbon nanostructures, obtained via hydrothermal synthesis from citric acid and ethylenediamine.