ß-Like DNA polymerases and prospects for their use as targets in chemotherapy of tumors.

DNA polymerases ß are enzymes that perform repair of damaged DNA. In the cells of malignant tumors, there is a change in the production and properties of these enzymes, which is accompanied by altered viability of tumor cells. Analysis of the publications available in Russian and international databases (Pubmed, Elsevier) on the structure and properties of DNA polymerases ß and their role in cell growth and proliferation, published over the past 20 years, has shown overexpression of genes encoding ß-like DNA polymerases in many types of malignant tumors cells. This explains the maintenance of their viability and proliferative activity. Targeted inhibition of ß-like DNA polymerases is accompanied by antiproliferative and antitumor effects. Stable paramagnetic isotopes of magnesium (25Mg2+) or other divalent metals (43Ca2+ and 67Zn2+) with uncompensated nuclear spin isotopes, as well as short single-stranded polydeoxyribonucleotides, can be used as promising antitumor pharmacophores.

Prolonged Orbital Relaxation by Locally Modified Phonon Density of States for the SiV

Coherent quantum systems are a key resource for emerging quantum technology. Solid-state spin systems are of particular importance for compact and scalable devices. However, interaction with the solid-state host degrades the coherence properties. The negatively charged silicon vacancy center in diamond is such an example. While spectral properties are outstanding, with optical coherence protected by the defects symmetry, the spin coherence is susceptible to rapid orbital relaxation limiting the spin dephasing time. A prolongation of the orbital relaxation time is therefore of utmost urgency and has been tackled by operating at very low temperatures or by introducing large strain. However, both methods have significant drawbacks: the former requires use of dilution refrigerators and the latter affects intrinsic symmetries. Here, a novel method is presented to prolong the orbital relaxation with a locally modified phonon density of states in the relevant frequency range, by restricting the diamond host to below 100 nm. Subsequently measured coherent population trapping shows an extended spin dephasing time compared to the phonon-limited time in a pure bulk diamond. The method works at liquid helium temperatures of few Kelvin and in the low-strain regime.

[The organization of pre-clinical studies of bactericidal and wound healing effects of the impulse photoherapy device "Zarya"].

The purpose of the study is to determine therapeutic effectiveness of the pulsed high intensity optical irradiation device "Zarya" exemplified by treatment of model wounds in laboratory animals and to compare with traditional methods of wound treatment. The prototype of "Zarya" device was used whose operating principle was based on pulsed irradiation of affected areas with high intensity optical radiation in continuous spectrum generated by pulsed xenon lamp. The therapeutic effect of the "Zarya" device was compared with effectiveness of the certified medical ultraviolet irradiator based on low-pressure mercury lamp and also with known wound-healing and antibacterial medication Levomekol ointment. The mature male rats of Wistar line were used in the study. The animals were distributed to 4 groups: group 1 was irradiated by "Zarya" device, group 2 was irradiated by low-pressure mercury lamp, group 3 was treated with Levomekol ointment and group 4 was exposed to no exposure. The linear wound was modeled according to the standard method under ether anesthesia. The therapeutic procedures were applied daily during 7 days. The bactericidal effect was studied on the basis of smears from wound onto flora on the 2nd, 5th and 7th day. On the 8th day the animals were subjected to euthanasia. It was established that "Zarya" device application permits to reduce considerably both duration of therapeutic procedures and therapy course in general and also to achieve more pronounced bactericidal effect. The obtained data is supposed to be used for development of program of clinical trials.

Role of the Lifshitz topological transitions in the thermodynamic properties of graphene.

The origin of the Lifshitz topological transition (LTT) and the 2D nature of the LTT in graphene has been established. The peculiarities of the Lifshitz topological transitions in graphene are described at the Brillouin zone centre Γ, the zone corners K in the vicinity of the Dirac points, and at the saddle point M. A general formulation of the thermodynamics at the LTT in graphene is given. The thermodynamic characteristics of graphene are investigated at the Lifshitz topological transitions. Anomalies are found in the electron specific heat C e, the electron thermal coefficient of pressure, and the coefficients of electron compressibility and thermal expansion in graphene at the LTT. All the thermodynamic parameters possess the strongest singularities in graphene at the LTT near the saddle points. This opens exciting opportunities for inducing and exploring the Lifshitz topological transitions in graphene.

InSe as a case between 3D and 2D layered crystals for excitons.

InSe is a promising material in many aspects where the role of excitons is decisive. Here we report the sequential appearance in its luminescence of the exciton, the biexciton, and the P-band of the exciton-exciton scattering while the excitation power increases. The strict energy and momentum conservation rules of the P-band are used to reexamine the exciton binding energy. The new value ≥20 meV is markedly higher than the currently accepted one (14 meV), being however well consistent with the robustness of the excitons up to room temperature. A peak controlled by the Sommerfeld factor is found near the bandgap (~1.36 eV). Our findings supported by theoretical calculations taking into account the anisotropic material parameters question the pure three-dimensional character of the exciton in InSe, assumed up to now. The refined character and parameters of the exciton are of paramount importance for the successful application of InSe in nanophotonics.

Localization and transient emission properties in InGaN/GaN quantum wells of different polarities within core-shell nanorods.

Transient photoluminescence (PL) characteristics and localization phenomena in InGaN/GaN core-shell nanorods (NRs) were investigated from 6 K up to 285 K. The NRs exhibit three well-defined PL bands in the near-UV, blue, and green range ascribed to the emission of quantum well (QW) areas situated at the (1.00) sidewalls, (10.1) top facets, and (00.1) tip, respectively. At low temperature, time-resolved PL shows a fast decay time of about 0.5 ns for the semi- and non-polar QWs, while the polar QWs exhibit at least a twice-longer time. Rapid delocalization of carriers above 50 K indicates shallow potential fluctuations in the QWs. At room temperature, the characteristic fast PL decay time of the three QW bands stabilizes around 300 ps. The slow decaying PL components have different characteristic decay times that are explained by additional localization at basal stacking faults (BSFs), taking into account the quantum confined Stark effect. In addition, narrow excitonic luminescence lines are observed in the BSF-enriched polar QWs, providing direct evidence of the impact of the BSF/QW crossings on the optical properties of the NRs. A PL rise time of about 100 ps does not show any deviation between bands. These findings are suggestive of similar transport mechanisms in temperature equilibrium without inter-facet transport between different QWs. We believe that predictable transient characteristics can play a key role in creating uniform NR ensembles for device applications.

Towards the indium nitride laser: obtaining infrared stimulated emission from planar monocrystalline InN structures.

The observation of a stimulated emission at interband transitions in monocrystalline n-InN layers under optical pumping is reported. The spectral position of the stimulated emission changes over a range of 1.64 to 1.9 µm with variations of free electron concentration in InN layers from 2·1019 cm-3 to 3·1017 cm-3. The main necessary conditions for achieving the stimulated emission from epitaxial InN layers are defined. In the best quality samples, a threshold excitation power density is obtained to be as low as 400 W/cm2 at T = 8 K and the stimulated emission is observed up to 215 K. In this way, the feasibility of InN-based lasers as well as the potentials of crystalline indium nitride as a promising photonic material are demonstrated.

Insight into the performance of multi-color InGaN/GaN nanorod light emitting diodes.

We report on the thorough investigation of light emitting diodes (LEDs) made of core-shell nanorods (NRs) with InGaN/GaN quantum wells (QWs) in the outer shell, which are grown on patterned substrates by metal-organic vapor phase epitaxy. The multi-bands emission of the LEDs covers nearly the whole visible region, including UV, blue, green, and orange ranges. The intensity of each emission is strongly dependent on the current density, however the LEDs demonstrate a rather low color saturation. Based on transmission electron microscopy data and comparing them with electroluminescence and photoluminescence spectra measured at different excitation powers and temperatures, we could identify the spatial origination of each of the emission bands. We show that their wavelengths and intensities are governed by different thicknesses of the QWs grown on different crystal facets of the NRs as well as corresponding polarization-induced electric fields. Also the InGaN incorporation strongly varies along the NRs, increasing at their tips and corners, which provides the red shift of emission. With increasing the current, the different QW regions are activated successively from the NR tips to the side-walls, resulting in different LED colors. Our findings can be used as a guideline to design effectively emitting multi-color NR-LEDs.

In Vitro Effects of Sodium Nitroprusside and L-Nω-Nitroarginine Methyl Ester (L-NAME) on Activity of Lysosomal Cysteine Proteinases and Lysosomal Membrane Permeability.

The direct effect of 5 mM L-NAME and 0.1 mM sodium nitroprusside on activity of lysosomal cysteine proteinases and permeability of lysosomal membrane was studied in vitro after 1, 2, and 4 h of incubation. Isolated from the liver of intact female rats lysosome suspensions were used. Both substances reduced total activity of cathepsin H and did not affect cathepsin B at all time intervals. L-NAME increased cathepsin L activity at all incubation times, while sodium nitroprusside increased activity of this enzyme after 2-h incubation and reduced it incubation after 4-h incubation. L-NAME demonstrated a membrane-destabilizing effect in in vitro experiments, while sodium nitroprusside on the contrary stabilized lysosomal membranes.

[The results of universal audiological screening of newborn infants in the Astrakhan region]. / Rezul'taty universal'nogo audiologicheskogo skrininga novorozhdennykh v Astrakhanskoi oblasti.

We have evaluated the results of universal audiological screening of 93 352 newborn infants performed in the Astrakhan region of the Russian Federation during the period from 2009 till 2015. The screening coverage amounted to 95%. The prevalence of hearing disorders was estimated at 1:1111 and that of their severe forms at 1:3000. The clinical significance of the examination during its first stage consists of the exclusion of evoked otoacoustic emission. After the completion of the second stage, it is necessary to carry out the regular medical follow up observation of the children suffering from hearing impairment and to undertake the early rehabilitative treatment based on the application of hearing aids and prosthetic devices. Sensorineural hearing loss was found to be the predominant form of hearing disorders in the children during the first year of life (80%). The impairment of hearing was documented in 22.3% of the premature children which suggests the necessity of long-term monitoring of evoked otoacoustic emission in these patients.

Lattice and magnetic dynamics of a quasi-one-dimensional chain antiferromagnet PbFeBO4.

A group of recently synthesized orthorhombic Pnma crystals PbMBO4 (M = Cr, Mn, Fe) demonstrates a number of unusual structural and magnetic properties. We report on polarized Raman scattering study of the lattice and magnetic dynamics in single crystals of an antiferromagnet PbFeBO4 below and above [Formula: see text] K. Polarization properties of the observed magnetic excitations below T N as well as intense quasi-elastic scattering support the quasi-one-dimensional character of the magnetic structure of PbFeBO4. Frequency overlapping of magnetic excitations and low-frequency phonons in the range of 90-200 cm-1 leads to pronounced asymmetric anomalies thus confirming intrinsic coupling of magnetic and lattice subsystems. This conclusion is also supported by observation of anomalous temperature behaviour of higher frequency phonons in the vicinity of T N. Experimental investigations are supported by relevant magnetic symmetry analysis which allows us to explain previously observed anomalous results.

[Arm Motor Function Recovery during Rehabilitation with the Use of Hand Exoskeleton Controlled by Brain-Computer Interface: a Patient with Severe Brain Damage].

We studied the dynamics of motor function recovery in a patient with severe brain damage in the course of neurorehabilitation using hand exoskeleton controlled by brain-computer interface. For estimating the motor function of paretic arm, we used the biomechanical analysis of movements registered during the course of rehabilitation. After 15 weekly sessions of hand exoskeleton control, the following results were obtained: a) the velocity profile of goal-directed movements of paretic hand became bell-shaped, b) the patient began to extend and abduct the hand which was flexed and adducted in the beginning of rehabilitation, and c) the patient began to supinate the forearm which was pronated in the beginning of rehabilitation. The first result is an evidence of the general improvement of the quality of motor control, while the second and third results prove that the spasticity of paretic arm has decreased.

Optically Addressable Silicon Vacancy-Related Spin Centers in Rhombic Silicon Carbide with High Breakdown Characteristics and ENDOR Evidence of Their Structure.

We discovered a family of uniaxially oriented silicon vacancy-related centers with S=3/2 in a rhombic 15R-SiC crystalline matrix. We demonstrate that these centers exhibit unique characteristics such as optical spin alignment up to the temperatures of 250°C. Thus, the range of robust optically addressable vacancy-related spin centers is extended to the wide class of rhombic SiC polytypes. To use these centers for quantum applications it is essential to know their structure. Using high frequency electron nuclear double resonance, we show that the centers are formed by negatively charged silicon vacancies V_{Si}^{-} in the paramagnetic state with S=3/2 that is noncovalently bonded to the neutral carbon vacancy V_{C}^{0} in the nonparamagnetic state, located on the adjacent site along the SiC symmetry c axis.

III-nitride tunable cup-cavities supporting quasi whispering gallery modes from ultraviolet to infrared.

Rapidly developing nanophotonics needs microresonators for different spectral ranges, formed by chip-compatible technologies. In addition, the tunable ones are much in demand. Here, we present site-controlled III-nitride monocrystal cup-cavities grown by molecular beam epitaxy. The cup-cavities can operate from ultraviolet to near-infrared, supporting quasi whispering gallery modes up to room temperature. Besides, their energies are identical in large 'ripened' crystals. In these cavities, the refractive index variation near an absorption edge causes the remarkable effect of mode switching, which is accompanied by the spatial redistribution of electric field intensity with concentration of light into a subwavelength volume. Our results shed light on the mode behavior in semiconductor cavities and open the way for single-growth-run manufacturing the devices comprising an active region and a cavity with tunable mode frequencies.

Age-Specific Peculiarities of Modulation of Blood Aldo-Keto Reductase Isoenzyme Spectrum.

The aldo-keto reductase spectrum of the blood was studied at different stages of ontogeny to elucidate the role of reduction pathway in utilization of the carbonyl products of free radical oxidation in modulation of organism sensitivity to the damaging effect of stress during ontogeny. The studies revealed the age-specific changes in aldo-keto reductase spectrum in the blood. An analogy of the aldo-keto reductase spectrum structure in animals of early maturity and in old rats was found. The appearance of age specificity of the aldo-keto reductase spectrum in the blood creates metabolic prerequisites for changes in the efficiency of utilization of carbonyl products of free radical oxidation via their reductive transformation.

[EXPERIMENTAL TESTING OF THE OPERATOR'S PERCEPTION OF SYMBOLIC INFORMATION ON THE HELMET-MOUNTED DISPLAY DEPENDING ON THE STRUCTURAL COMPLEXITY OF VISUAL ENVIRONMENT].

The experiments showed that pilot's perception of symbolic information on the helmet-mounted display (HMD) depends on type of HMD (mono- or binocular), and structural complexity of the background image. Complex background extends time and increases errors in perception, particularly when monocular HMD is used. In extremely complicated visual situations (symbolic information on a background intricately structured by supposition of a TV image on real visual environment) significantly increases time and lowers precision of symbols perception no matter what the HMD type.

The expression of CCN2, IQSEC, RSPO1, DNAJC15, RIPK2, IL13RA2, IRS1, and IRS2 genes in blood of obese boys with insulin resistance.

The development of obesity and its metabolic complications is associated with dysregulation of various intrinsic mechanisms, which control basic metabolic processes via changes in the expression of numerous regulatory genes. We studied the expression of the subset of genes, which responsible for control of cell growth and glucose metabolism, in blood cells of obese boys with normal and impaired insulin sensitivity as well as in normal (control) individuals. It was shown that obesity with normal insulin sensitivity enhances the expression of IRS1, RIPK2, IL13RA2, RSPO1, IQSEC, and CCN2 genes but decreases the expression level IRS2 and DNAJC15 genes in the blood cells as compared to control group. Insulin resistance in obese boys leads to up-regulation of IRS2, RSPO1, and DNAJC15 gene expressions as wells to down-regulation of IRS1 and RIPK2 genes in the blood cells versus obese patients with normal insulin sensitivity. Results of this study provide evidence that obesity affects the expression of the subset of genes related to cell growth and glucose metabolism in blood cells and that insulin resistance in obesity is associated with changes in the expression level of IRS1, IRS2, RIPK2, RSPO1, and DNA JC15 genes, which contribute to the development of insulin resistance and glucose intolerance and possibly reflect some changes in fat tissue.

[Propagation of autowaves in capillaries thick with moving viscous excitable medium].

We consider the propagation of autowaves in the moving liquid excitable medium. The shapes of the autowave fronts in cases of the Poiseuille and Couette flows are determined in flat capillaries within a kinematic approach. We show the existence of a critical velocity for the flows above which the autowave fronts should break off. The possibility of a diode effect--the one-way capillary conductivity--is studied. The results of computer simulations are in good agreement with the theoretical predictions.

[EXPRESSION OF GENES, WHICH CONTROL GLUCOSE METABOLISM, IN BLOOD CELLS OF THE OBESE BOYS WITH INSULIN RESISTANCE].

We studied the expression of genes, which responsible for glucose metabolism, in the blood of obese boys with and without of insulin resistance as well as in normal (control) individuals. It was shown that the expression level of PFKFB3 gene is increased, PFKFB1 and INSIG2--is decreased, but HK2 gene--significantly does not change in the blood cells of obese boys with normal insulin sensitivity as compared to control group. Insulin resistance in obese boys leads to up-regulation of INSIG2 gene expression as well as to down-regulation of PFKFB1, PFKFB3, and HK2 genes in the blood.cells as compared to obese patients with normal insulin sensitivity. Results of this study provide evidence that obesity affects the expression of the subset of glucose metabolism-related genes in the blood cells and that insulin resistance in obesity is associated with changes in the expression level of PFKFB1, PFKFB3, HK2, and INSIG2 genes, which contribute to the development of insulin resistance as well as glucose intolerance.

[Experimental studies of reliability of symbolic information perception from the aviation LCD panel].

Results of tachistiscopic experiments on reliability of symbol recognition on LCD panel as a function of screen definition (640 x 480, 800 x 600 and 1024 x 768 pixels), angular size of a picture element (10, 15, 20 and 30 angular min) and luminance contrast (LC) with the background (0.2 to 1.4 standard units) are presented. The obtained quantitative relations indicate significance of the above parameters for recognition reliability. Symbols with the size of 30 angular min and LC of 0.5 were recognizable irrespective of screen definition in the study. Recognition of symbols 20 and 15 angular min of size was much dependent on screen definition and LC of symbols. For symbols of size 10 angular min and LC ≥ 1.0 the recognition probability did not exceed 0.59-0.7.