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The development of technology for integrating optical metaresonators with two-dimensional and layered van der Waals (vdW) materials opens up broad prospects for the creation of subdiffraction concentrators of electromagnetic energy, surface-emitting lasers, laser displays, and highly efficient nonlinear converters. In this work, we develop a straightforward strategy for the design and fabrication of surface-emitting laser devices based on few-layer transition metal dichalcogenides placed on the dielectric metasurfaces in the regime of quasi-trapped mode excitation. We optimize the parameters of MoTe2 flake and Si metasurface to achieve a positive feedback and to observe the lasing, resulting from their integration, with the predicted characteristics. Promising potential for the development of vdW-metalaser platform is associated with the possibility of simple polarization control of lasing regimes by employing the features of the bianisotropic response of the metasurface's building blocks. [ABSTRACT FROM AUTHOR]

The immobilization of N,N‐diallyl‐N,N‐dimethylammonium chloride (DADMAC) on low‐density polyethylene (LDPE) films was carried out by the method of postradiation grafting using x‐ray radiation. The introduction of polycation exchanger links provided the appearance of hydrophilicity of the surface of the modified film. By measuring the wetting contact angle, IR and SEM, the island‐type character of the coating from grafted polyDADMAC was detected. The death of Gram‐negative bacteria Pseudomonas aeruginosa, Gram‐positive bacteria Staphylococcus aureus, and yeast (eukaryotes) Yarrowia lipolytica on the surface of the film with grafted polyDADMAC was demonstrated. [ABSTRACT FROM AUTHOR]

Multilevel interventions in healthcare settings (e.g. Ask, Advise, and Connect; AAC) can reduce tobacco product use among adult patients: their effectiveness in pediatric practice is largely unknown. We implemented an AAC model in pediatric primary care to deter children's tobacco use, and evaluated its effectiveness in a single-arm trial. At wellness visits, young patients (ages 12–17) completed a tablet-based assessment (Ask) of lifetime and current tobacco use. These data were made available within the electronic health record to pediatric primary care providers for preventive counseling (Advise). Providers then referred patients to an e-health evidence-based tobacco control intervention (Connect). Tobacco control outcomes were examined in the clinic population (N = 2219) and in a sample of patients (N = 388, 62% female, 39% non-White, M age = 15) over time, along with intervention engagement. Population use of tobacco products decreased following introduction of AAC (more than 2-fold). At the patient level, most children (80.9%) engaged with the intervention: those who were Black or African American, who never used tobacco products/were not susceptible to use, and who used fewer non-cigarette tobacco products were more likely to engage, but only after multiple prompts versus a single prompt. Engagement was positively associated with lowering children's susceptibility to using tobacco at follow-up. A pediatric AAC model holds promise in deterring youth tobacco use, including among historically marginalized populations who may require additional support. [ABSTRACT FROM AUTHOR]

Layered composite materials based on niobium and cermet are produced via the self-propagating high-temperature synthesis of preliminarily structured samples using metal foils (Ti, Nb, Ta, Ni) and reaction tapes (Ti + 1.7B) and (5Ti + 3Si). The reaction tapes for synthesis are produced by rolling powder mixtures. The microstructure, and elemental and phase compositions of the synthesized multilayer composite materials are studied by scanning electron microscopy and X-ray phase analysis. Particular attention is paid to the formation of intermediate layers and surface modification occurring during combustion. The strength characteristics of the synthesized materials are determined according to the three-point loading scheme at temperatures of 1100°C. Analysis of the obtained materials shows that joining in the combustion mode of metal foils and reaction tapes is provided due to reaction diffusion, mutual impregnation, and chemical reactions occurring in the reaction tapes and on the surface of the metal foils. The formation of thin intermediate layers in the form of cermet and eutectic solutions provides the synthesized multilayer materials with good strength properties up to 87 MPa at 1100°C. These results are of interest for the development of structural materials operating under extreme conditions. [ABSTRACT FROM AUTHOR]

This paper describes the compounds of refractory metal foils (Ti, Hf, Ta, and Ni) with ceramic layers formed as a result of combustion of reaction tapes rolled from Ti + 0.65C, Ti + 1.7B, and 5Ti + 3Si powder mixtures. Scanning electron microscopy and X-ray diffraction analysis are applied to study the microstructure, elemental composition, and phase composition of multilayer composites obtained by self-propagating high-temperature synthesis. The effect of synthesis conditions (initial temperature and applied pressure) and the initial structure of the samples on various parameters (combustion wave front propagation velocity, microstructure, phase composition, and strength properties) of the resulting layered materials is revealed. It is shown that compounds of metal foils and reaction tapes rolled from powder mixtures during combustion are ensured due to reaction diffusion, mutual impregnation, and chemical reactions occurring in the reaction tapes and on the surface of metal foils. The strength properties of the resulting materials (up to 275 MPa at 25°C and up to 72 MPa at 1100°C) are determined using a three-point loading scheme. The results of this study can contribute to the development of structural materials operating under extreme conditions. [ABSTRACT FROM AUTHOR]

This paper investigates the inverse problem for the non-stationary radiation transfer equation, which involves finding the attenuation coefficient using the data of serial irradiation of the medium with pulses of various durations. In the framework of single and double scattering approximations, we obtain asymptotic estimates of the scattered radiation flux density for a short duration of the probing pulse. We propose extrapolation procedures for the ballistic component of the radiation transfer equation solution using the data of multiple irradiations of the medium by pulsed radiation sources, which allows us to obtain approximate formulas for finding the attenuation coefficient. The results of numerical experiments with a well-known digital phantom confirm the effectiveness of the extrapolation algorithm for improving the quality of tomographic images of scattering media. [ABSTRACT FROM AUTHOR]

The work is devoted to the experimental study of the possibility to apply a protective silicide coating on an alloy based on zirconium (E110) by atmospheric plasma spraying. Coatings based on the binary eutectic Mo5Si3 + MoSi2 are deposited onto the surface of an E110 alloy sheet. The features of the structure and phase composition of the coatings after deposition and their evolution as a result of isothermal annealing at a temperature of 1300°C are studied. Upon the rapid cooling of silicide particles during coating, nonequilibrium phases are formed. As a result of annealing, the phase composition changes, which corresponds to the phase diagram. The kinetics of the diffusion interaction between the coating and the base material is studied. The possibility of successfully protecting zirconium alloy from oxidation at 1100°C in air by the complex deposition of a coating of molybdenum silicides is shown for the first time. The minimum radius of curvature of the surface of the protected samples is about 1 mm. [ABSTRACT FROM AUTHOR]

Ti/Ta/Hf/Ni/ceramic layered composite materials are produced via the self-propagating high-temperature synthesis (SHS) of prestructured samples using metal foils (Ti, Hf, Ta, Ni) and reaction tapes (Ti + 0.65C), (Ti + 1.7B) and (5Ti + 3Si). The reaction tapes are prepared by cold rolling from powder mixtures. The microstructure, and elemental and phase compositions of the synthesized multilayer composite materials are characterized by scanning-electron microscopy (SEM) and X-ray phase analysis. The formation of intermediate layers and modification of the surface of the metal foils is given individual attention. Their flexural strength is determined according to the scheme of three-point loading at temperatures of 25 and 1100°С. Microstructure analysis of the produced materials shows that the joining of the metal foils and reaction tapes in the combustion mode is facilitated due to reaction diffusion, mutual impregnation, and chemical reactions occurring in the reaction tapes and on the surface of metal foils. The formation of thin intermediate layers in the form of cermets and eutectic solutions provides the synthesized multilayer materials with good strength properties (up to 275 MPa at 25°С, up to 72 MPa at 1100°С). These results are of interest for the development of construction materials operating under extreme conditions. [ABSTRACT FROM AUTHOR]

The emergence of new materials and fabrication techniques provides progress in the development of advanced photonic and communication devices. Transition metal dichalcogenides (e.g., molybdenum disulfide, MoS2) are novel materials possessing unique physical and chemical properties promising for optical applications. In this paper, a metasurface composed of particles made of bulk MoS2 is proposed and numerically studied considering its operation in the near‐infrared range. In the bulk configuration, MoS2 has a layered structure being a uniaxial anisotropic crystal demonstrating an optical birefringence property. It is supposed that the large‐scale and uniform MoS2 layers are synthesized in a vertical‐standing morphology, and then they are patterned into a regular 2D array of disks to form a metasurface. The natural anisotropy of MoS2 is utilized to realize the splitting of electric and magnetic dipole modes of the disks while optimizing their geometric parameters to bring the desired modes into overlap. At the corresponding resonant frequencies, the metasurface behaves as either an electric or a magnetic mirror, depending on the polarization of incident light. Based on the extraordinary reflection characteristics of the proposed metasurface, it can be considered an alternative to traditional mirrors and optical splitters when designing compact and highly efficient metadevices, which provide polarization and phase manipulation of electromagnetic waves on a subwavelength scale. [ABSTRACT FROM AUTHOR]

This experimental work briefly describes the technology of multiple electron-beam melting to produce low-alloy molybdenum alloys with other carbide-forming elements and carbon. Two new alloys described here allow deformation by cold rolling down to a thickness of 0.17 mm. When modifying the Golovin–Sims formula, we show that an alloy with fine (30–200 nm) carbides is hardened during cold rolling much more strongly than an alloy, in which only coarse (≥1 μm) carbides are present. The evolution of continuity defects with the deformation during cold rolling is traced. [ABSTRACT FROM AUTHOR]

Featured Application: The possible application of the considered effects can be associated with the design and development of a three-frequency narrowband polarizing beam splitters used in an optical routing systems. The features of polarization control of multiple multiresonances for quasi-trapped modes excited by synchronization of bianisotropic dipole responses in MoS 2 disks with a hole are considered. Using numerical calculations with analytical multipole analysis, we showed that the presence of a strong optical anisotropy of MoS 2 nanoparticles provides an additional degree of freedom and makes it possible to observe several resonances of electric and magnetic dipoles at once in a narrow spectral range. Based on the simulation results, we obtained the frequency dependences for the dipole polarizabilities of the MoS 2 disk with a hole, which can be used to distinguish the contributions of the nonlocal and bianisotropic dipole responses and possessing several features in the near-infrared range. Using the polarizability spectra of single nanoparticles and applying the tuning strategy, the design of the MoS 2 metasurface placed in air and supporting three resonances of quasi-trapped modes at once in a narrow spectral range was developed. One of these resonances corresponds to the telecom wavelength of about 1550 nm. The spectrum of light reflection for the MoS 2 metasurface is characterized by three narrowband dips corresponding to the wavelengths of the quasi-trapped modes. It was shown that a change in the polarization of a wave normally incident on the metasurface to orthogonal one leads to a change in the type of bianisotropic response excited in each MoS 2 disk and to the excitation of three other features in the reflection spectrum of the metasurface at wavelengths close to the initial values. [ABSTRACT FROM AUTHOR]

The inverse problem for the non-stationary radiative transfer equation is considered, which consists in finding the attenuation coefficient according to the pulsed multi-energy X-ray exposure. For a short duration of the probing pulse, the asymptotic solution of the inverse problem is found. The problem of identifying an unknown substance by attenuation coefficients approximately found on a finite set of energy values is formulated. Algorithms for solving identification problems are proposed. The results of the numerical simulation are presented for a wide range of substances of interest in medical computed tomography. [ABSTRACT FROM AUTHOR]

This paper presents the stability-evaluation outcomes of a multimachine power system (MMPS) connected with a large-scale hybrid wind farm (WF) and photovoltaic (PV) farm or hybrid wind/PV farm (HWPF) and a hybrid energy-storage system (HESS) consisting of a vanadium redox flow battery (VRFB) and a supercapacitor (SC). A probability scheme is used to determine the rated power of the proposed HESS, where the capacities of the VRFB-ESS and the SC-ESS are designed to effectively utilize their operating features. The control strategy of the HESS is proposed to reduce the pressure of the VRFB-ESS and smooth the output power fluctuations of the HWPF. The steady-state stability, small-signal stability, dynamic performances, and transient simulations of the studied grid-tied HWPF fed to the MMPS with and without the HESS are achieved. The simulation outcomes show that the proposed HESS can enhance the stability and power-smoothing performance of the HWPF fed to the MMPS. [ABSTRACT FROM AUTHOR]

Manipulation of resonant dielectric nanostructures is of paramount importance for next-generation photonic devices. Traditionally, researchers use two-dimensional or phase-change materials for this purpose. However, the former leads to small efficiency, while the latter lacks continuous changes. Here, we provide an alternative approach through laser-induced modification. Specifically, via a laser ablation process we synthesized molybdenum disulfide (MoS2) nanoparticles (NPs), the composition of which we then controlled through laser fragmentation. It causes a transformation of MoS2 into its oxide MoO3−x, which, in turn, results in pronounced modification of the optical response, owing to a large difference between their optical constants. In addition, laser-fragmented NPs have a several times larger photothermal response, compared to the original MoS2 and classical silicon NPs. Thus, our MoS2-based laser-tunable NPs open up a new perspective for resonant nanophotonics, in particular, photothermal therapy. [ABSTRACT FROM AUTHOR]

Nine species of hoverflies of the subfamilies Eristalinae, Pipizinae and Syrphinae are recorded from Ukraine for the first time: Cheilosia himantopus (Panzer, 1798), Orthonevra incisa (Loew, 1843), Neocnemodon verrucula (Collin, 1931), Pipiza luteibarba Vujić, Radenković & Polić, 2008, Trichopsomyia joratensis (Goeldlin de Tiefenau, 1997), T. lucida (Meigen, 1822), Dasysyrphus neovenustus Soszyński, Mielczarek & Tofi lski, 2013, Platycheirus europaeus Goeldlin de Tiefenau, Maibach & Speight, 1990, P. sticticus (Meigen, 1822). Distributions of these species are summarized and species diagnoses are provided. [ABSTRACT FROM AUTHOR]

A model has been proposed to describe the laser generation of two-dimensional semiconductor films with near-field pumping by quasitrapped modes excited in dielectric metasurfaces. A metastructure consisting of a Si metasurface coated with a MoTe2 film, where narrow-band resonance of a quasitrapped mode is joined with a broad exciton resonance of a two-dimensional material, has been designed. Threshold conditions for generation in the MoTe2 film with pumping by quasitrapped modes have been determined. The possibility of polarization control of the emission of the proposed metastructure has been demonstrated. [ABSTRACT FROM AUTHOR]

The study is devoted to searching for possibilities to improve the thermal stability of protective silicide coatings on zirconium alloys by reducing the intensity of their diffusion interaction with the base material. The possibilities of forming barrier layers both from molybdenum silicides with a reduced silicon content and from tungsten are experimentally evaluated. The structural and phase state of diffusion pairs subjected to vacuum annealing at temperatures of 1100–1450°C for 3–9 hours are studied by scanning electron microscopy and X-ray spectral microanalysis. It is determined that a 1-μm-thick tungsten barrier layer reduces the degree of diffusion interaction between molybdenum silicides and a zirconium-based alloy. However, in the interaction region, a porous and brittle layer is formed, leading to peeling of the coating. A decrease in the average silicon content in molybdenum silicides can also significantly reduce the degree of their interaction with zirconium alloys, but does not lead to loss of coating adhesion. The features of the microstructure and chemical composition formed as a result of the diffusion interaction of phases are revealed. The effective kinetic parameters of the processes of diffusion interaction and their temperature dependence are determined. [ABSTRACT FROM AUTHOR]

We study the altered Cesàro space, which is a non-ideal enlargement of the usual Cesàro space. We establish some of its basic properties, we prove the connection of the space with one weighted Sobolev space of first order on the real line and give a full characterization of the associated spaces. [ABSTRACT FROM AUTHOR]

The problem of investigating the features of the anisotropic resonant response of single silicon nanoparticles with irregular shapes and metasurfaces fabricated from them is considered. The sizes of single nanoscale silicon cuboids were tuned for excitation of the dipole resonances in the near-infrared spectral range, and the metasurfaces composed of such nanoparticles were fabricated on a quartz substrate using lithographic methods. It is shown that the presence of the defect in the form of a cut edge of a nanoscale cuboid leads to the resonant excitation of minor components of the electric and magnetic dipole moments oriented perpendicularly to the polarization of the incident wave. The spectral position of such minor components for a cuboid with a defect corresponds to the position of the resonance of the main component for the same multipole in a cuboid without a defect. We performed the numerical optimization and determined the conditions for excitation of a resonant response for the cross-polarization component of the wave reflected from the metasurface composed of nanoscale cuboids with a defect. The developed method allows creating of the metasurfaces rotating the polarization plane, which can be used for the creation of the nanolayer polarization metacoatings allowing the polarization conversion. [ABSTRACT FROM AUTHOR]

The heat resistance of composite materials fabricated by diffusion welding under pressure and consisting of alternating layers of niobium, molybdenum, and Nb30Ti or Nb0.1C alloy or layers of Nb–Al, Ti–Al, or Mo–Al intermetallics has been studied. Two types of coatings, namely, ZrO2–Y2O3 sol–gel coating or electrochemical chromium–diamond coating, are deposited onto composite samples. The samples are subjected to heat resistance tests in air at temperatures of 800 and 1000°C. Nb30Ti/Al composite samples with a chrome–diamond coating demonstrate the highest heat resistance, which is several orders of magnitude higher than the heat resistance of uncoated niobium samples. [ABSTRACT FROM AUTHOR]

Within the framework of the nonstationary radiative transfer equation, we propose a new extrapolation method to improve the quality of tomographic images of the attenuation coefficient. The method is based on irradiation of the medium under study with a series of pulses of different duration. A numerical analysis of the proposed algorithm is carried out using a well-known test phantom. The results show that the algorithm effectively suppresses the negative influence of scattering in X-ray tomography of inhomogeneous media. [ABSTRACT FROM AUTHOR]

The machining precision in grinding a flexible shaft by sharp and blunt wheels is compared for a CNC system with a specified cycle of radial supply velocities. To that end, the margin removal is analyzed in grinding by sharp and blunt grinding wheels. The machining process is simulated by means of a digital twin of CNC plunge grinding. By that means, the actual supply velocity is calculated for specific parameters of the grinding cycle. A method is described for calculating the blunting of the abrasive grains in a blunt wheel with specified characteristics. The model of grinding is based on analytical relations specifying the functional relations of the cutting force with the specified cutting conditions, the geometry of the cutting zone, the wheel's characteristics and its dimensions, the cutting depth, and different degrees of grain blunting. [ABSTRACT FROM AUTHOR]

A system for predicting the machining error for a batch of parts in CNC wheel grinding is described; the system takes the influence of technological variables into account. Analysis of their combined influence on the machining error is based on a digital twin of the plunge grinding process. The variable machining conditions for the batch of parts (shafts) is taken into account by simulating the influence of the following factors on the machining precision: fluctuations in the margin; the blunting of the wheel grains before dressing; the pliability of the machining system over the grinding length; and positions of the active monitoring instrument in cross sections of the workpiece corresponding to different pliability of the machining system. [ABSTRACT FROM AUTHOR]

Pharmacists, as highly accessible members of the healthcare team, have considerable potential to address tobacco use among patients. However, while published data suggest that pharmacists are effective in helping patients quit, barriers exist to routine implementation of cessation services in community pharmacy settings. Within the context of a randomized trial (n = 64 pharmacies), surveys were administered over a period of 6 months to assess pharmacists' perceptions of factors associated with the implementation of "Ask-Advise-Refer", a brief intervention approach that facilitates patient referrals to the tobacco quitline. Study measures, grounded in Rogers' Diffusion of Innovations Theory, assessed pharmacists' perceptions of implementation facilitators and barriers, perceptions of intervention materials provided, and perceived efforts and personal success in implementing Ask-Advise-Refer at 6-months follow-up. Findings indicate that while the brief intervention approach was not difficult to understand or implement, integration into normal workflows presents greater challenges and is associated with overall confidence and implementation success. Lack of time was the most significant barrier to routine implementation. Most (90.6%) believed that community pharmacies should be active in promoting tobacco quitlines. Study results can inform future development of systems-based approaches that lead to broad-scale adoption of brief interventions, including but not limited to tobacco cessation, in pharmacy settings. [ABSTRACT FROM AUTHOR]

The elemental, phase, and structural state of Nb–Mo–C alloys with equiatomic metal contents and 15, 20, 25, and 30 at % C are studied after electron-beam zone melting. In the alloy containing 15 at %, a fine microstructure, which is typical of eutectic alloys, forms; as the carbon content increases, primary carbide crystals appear in the alloy structure. The main carbide phase in all alloys is found to be an NbC-based carbide rather than an Nb2C-based carbide. The component distribution between the phases is studied as a function of the average alloy composition. The results of short-time strength tests of alloy specimens at room temperature and at 1500°C and also their high-temperature bending creep tests are presented. The 100-h creep strength maximum for the alloys is shown to be 200–300 MPa at 1500°C ( = 200–300 MPa). [ABSTRACT FROM AUTHOR]

Dual-energy radiography is a relatively simple but powerful tool of X-ray diagnosis. It increases the diagnostic value of radiographic examination by generating separate images of bony and soft tissues. In two-shot dual-energy radiography, separate images of tissues are constructed from the two initial images obtained at different anode voltages. The process of acquiring the initial images is extended in time and includes a pause between exposures. The result is that the separate tissue-selective images can carry motion artifacts, reducing their diagnostic value. In this study we consider ways of reducing motion artifacts. [ABSTRACT FROM AUTHOR]

The paper considers the mathematical problems of constructing sonar images of the seabed from the data of measurements of a multibeam side-scan sonar. For the nonstationary radiative transfer equation describing the process of acoustic sounding in the ocean, we investigate the inverse problem of finding the discontinuity lines of the bottom scattering coefficient. A numerical algorithm for solving the inverse problem is developed, and the analysis of the quality of localization of the boundaries of inhomogeneities of the seabed depending on the number of angles and the sounding range is carried out. [ABSTRACT FROM AUTHOR]

The kinetics of the diffusion interaction of a hypereutectic alloy of molybdenum silicides Mo5Si3 + MoSi2 with a reactor alloy of E110 grade based on zirconium is experimentally investigated. The structural and phase states of diffusion pairs subjected to vacuum annealing at 1100, 1200, and 1300°C for 3, 6, and 9 h are studied by scanning electron microscopy and energy-dispersive X-ray spectral microanalysis. In the entire investigated temperature range and for all exposures, zirconium silicides are formed due to diffusion interaction at the interface between the alloys of molybdenum and zirconium silicides. The silicon-transfer process is the primary diffusion process in the interaction of an alloy based on zirconium and molybdenum silicides. No signs of zirconium diffusion into molybdenum silicides are found, and the diffusion of molybdenum into zirconium is significantly limited. The features of the structure and chemical composition of the silicide phases formed in the region of diffusion interaction are revealed. A comparative analysis of the regions of diffusion interaction of silicides Mo5Si3 and MoSi2 with a zirconium alloy is carried out. The effective kinetic parameters of the processes of diffusion interaction at different temperatures, as well as the parameters of the temperature dependence of the effective parabolic constant of growth of the layer of intermediate phases arising during the annealing of diffusion pairs, are determined. [ABSTRACT FROM AUTHOR]

For the nonstationary radiative transfer equation, the inverse problem of determining the attenuation coefficient from a known solution at the domain boundary is considered. The structure and the continuous properties of the solution to an initial-boundary value problem for the radiative transfer equation are studied. Under special assumptions about the radiation source, it is shown that the inverse problem has a unique solution and a formula for the Radon transform of the attenuation coefficient is derived. The quality of the reconstructed tomographic images of the sought function is analyzed numerically in the case of various angular and time flux density distributions of the external source. [ABSTRACT FROM AUTHOR]

The aim of this study was to establish the mechanisms of action of a novel liposomal nitric oxide (NO) carrier on large-conductance Ca2+-activated channels (BKCa or Maxi-K) expressed in vascular smooth muscle cells (VSMCs) isolated from the rat main pulmonary artery (MPA). Experimental design comprised of both whole-cell and cell-attached single-channel recordings using the patch-clamp techniques. The liposomal form of NO, Lip(NO), increased whole-cell outward K+ currents in a dose dependent manner while shifting the activation curve negatively by about 50 mV with respect to unstimulated cells with the EC50 value of 0.55 ± 0.17 µM. At the single channel level, Lip(NO) increased the probability of the open state (Po) of Maxi-K channels from 0.0020 ± 0.0008 to 0.74 ± 0.02 with half-maximal activation occurring at 4.91 ± 0.01 μM, while sub-maximal activation was achieved at 10−5 M Lip(NO). Channel activation was mainly due to significant decrease in the mean closed dwell time (about 500-fold), rather than an increase in the mean open dwell time, which was comparatively modest (about twofold). There was also a slight decrease in the amplitude of the elementary Maxi-K currents (approximately 15%) accompanied by an increase in current noise, which might indicate some non-specific effects of Lip(NO) on the plasma membrane itself and/or on the phospholipids environment of the channels. In conclusion, the activating action of Lip(NO) on the Maxi-K channel is due to the destabilization of the closed conformation of the channel protein, which causes its more frequent openings and, accordingly, increases the probability of channel transition to its open state. [ABSTRACT FROM AUTHOR]

A general strategy for the realization of electric and magnetic quasi‐trapped modes located at the same spectral position is presented. This strategy's application makes it possible to design metasurfaces allowing switching between the electric and magnetic quasi‐trapped modes by changing the polarization of the incident light wave. The developed strategy is based on two stages: the application of the dipole approximation for determining the conditions required for the implementation of trapped modes at certain spectral positions and the creation of the energy channels for their excitation by introducing a weak bianisotropy in nanoparticles. Since excitation of trapped modes results in a concentration of electric and magnetic energies in the metasurface plane, the polarization switching provides possibilities to change and control the localization and distribution of optical energy at the sub‐wavelength scale. A practical method for spectral tuning of quasi‐trapped modes in metasurfaces composed of nanoparticles with a preselected shape is demonstrated. As an example, the optical properties of a metasurface composed of silicon triangular prisms are analyzed and discussed. [ABSTRACT FROM AUTHOR]

The research aim of this study is the development of a theoretical semiclassical model of the controllable excitation and propagation of surface plasmon polaritons (SPPs) in planar graphene waveguides by the application of external voltage. The model is based on the numerical solution of the SPP's dispersion equation formulated for a system including two coupled graphene sheets with embedded quantum dots. Using the developed model, the different near‐field patterns realized in the waveguides depending on the quantum dots' ordering and an external voltage applied independently to each graphene sheet with additional gold electrodes are numerically investigated. The obtained results show that the application of external voltage can locally change the chemical potential of graphene and, thereby, lead to controllable excitation of SPPs in the corresponding graphene waveguide. Furthermore, we revealed that the propagation direction of the excited SPPs is determined by the geometrical configurations of the gold electrodes that provide the required SPP routing. The investigated system offers new opportunities for near‐field energy transport and concentration, which can be applied to develop ultra‐compact photonic devices. [ABSTRACT FROM AUTHOR]

The proposed dynamic model of cutting-depth formation establishes a relation between factors such as the margin removed, the elastic deformation and dynamic properties of the machining system, the cutting force, and the kinematics of circular plunge grinding. The model permits calculation of the workpiece radii in the course of grinding. That, in turn, permits prediction of the resulting surface precision, taking account of the elastic deformation of the machining system and the grinding dynamics. The diametric error and radial wobble are calculated for specific examples. [ABSTRACT FROM AUTHOR]

In active monitoring, the position of the instrument may influence the accuracy and productivity of machining. This influence is considered in the present work for the example of CNC circular plunge grinding. Practical recommendations are made regarding the use of active monitoring in setting up the grinding cycle. Options for taking account of the length of the machined surface in the design of optimal plunge-grinding cycles are considered. [ABSTRACT FROM AUTHOR]

The structure, the strength at high temperatures, and the fracture toughness of the composites fabricated under various conditions of diffusion welding of stacks of Nb foils with coatings made of a mixture of Nb, Ti, Mo, Si, ZrH2, Cr, and Al powders are studied. The strength in the temperature range of 1100–1300°C changes from 490 to 350 MPa, the fracture toughness at room temperature is 15.6 MPa m1/2, and the creep resistance determined in 100-h tests at a residual strain tolerance of 1% at 1150°C is 90 MPa. [ABSTRACT FROM AUTHOR]

Composites with a layered structure are fabricated by a solid-phase technology using diffusion welding of stacks made of molybdenum foils with single- and double-sided (Si–C) coatings at a pressure of 10–14 MPa and a temperature of 1500°C. The structure of the composites is studied. The strength of the composites is 300 MPa at 1450°C, and the fracture toughness is 21 MPa m1/2 at room temperature. [ABSTRACT FROM AUTHOR]

The paper is concerned with the problem of construction of characterizing statistics for some types of distributions within certain classes. A characterizing statistic for multivariate normal distribution is constructed with the use of the theory of random matrices. Properties and characteristics of spherically symmetric distributions are studied. Examples of statistics that can be used for characterization of symmetric distributions are given. Applications of characterizing statistics to the theory of hypothesis testing are given. The problem of discrimination between the uniform and normal types of multivariate distributions within the group of spherically symmetric distributions from small samples is studied on the basis of the results obtained. A lower estimate is obtained for the number of observations that can serve as a basis for discrimination between these distributions. [ABSTRACT FROM AUTHOR]

The structures of J-aggregates of two monomethine dyes are compared at the meso- and nanoscale by using fluorescence and atomic force microscopy. The J-aggregates of the two dyes are found to have solely a monolayer structure and to be polymorphic. Morphologically, monolayers represent narrow skew-symmetric strips and symmetric rhombi in the case of the first and the second dyes. The second morphological type is the tubular type in both cases. For monolayers of both dyes, atomic force microscopy imaging at the ultimate resolution reveals the presence of a quasi-one-dimensional substructure consisting of densely packed nanostrips with a width in the range of 7–10 nm. The nanostrips are interpreted as building blocks emerging at early stages of monolayer crystallization that proceeds via a nonclassical multistep mechanism. [ABSTRACT FROM AUTHOR]

The microstructure, mechanical properties, and heat resistance of the laminated composites fabricated by high-pressure diffusion welding of a packet comprising alternating foils of niobium alloy with 5, 10, and 15 at % vanadium and aluminum are studied. The alternation of viscoplastic Nb–V alloy layers and strengthening aluminide layers is found to provide a high strength of the composites at 20–1300°C, which increases with the vanadium content in the alloy. [ABSTRACT FROM AUTHOR]

Let be a Lebesgue measurable function on an interval . We find conditions on under which the mapping is a continuous linear functional on a weighted first-order Sobolev space ; we also obtain estimates for the norm of this functional in . [ABSTRACT FROM AUTHOR]

Highlights: DNA kinking is inevitable for the highly anisotropic 1D–1D electrostatic interaction with the one-dimensionally periodically charged surface. The double helical structure of the DNA kinetically trapped on positively charged monomolecular films comprising the lamellar templates is strongly laterally stressed and extremely perturbed at the nanometer scale. The DNA kinetic trapping is not a smooth 3D—> 2D conformational flattening but is a complex nonlinear in-plane mechanical response (bending, tensile and unzipping) driven by the physics beyond the scope of the applicability of the linear worm-like chain approximation. Up to now, the DNA molecule adsorbed on a surface was believed to always preserve its native structure. This belief implies a negligible contribution of lateral surface forces during and after DNA adsorption although their impact has never been elucidated. High-resolution atomic force microscopy was used to observe that stiff DNA molecules kinetically trapped on monomolecular films comprising one-dimensional periodically charged lamellar templates as a single layer or as a sublayer are oversaturated by sharp discontinuous kinks and can also be locally melted and supercoiled. We argue that kink/anti-kink pairs are induced by an overcritical lateral bending stress (> 30 pNnm) inevitable for the highly anisotropic 1D-1D electrostatic interaction of DNA and underlying rows of positive surface charges. In addition, the unexpected kink-inducing mechanical instability in the shape of the template-directed DNA confined between the positively charged lamellar sides is observed indicating the strong impact of helicity. The previously reported anomalously low values of the persistence length of the surface-adsorbed DNA are explained by the impact of the surface-induced low-scale bending. The sites of the local melting and supercoiling are convincingly introduced as other lateral stress-induced structural DNA anomalies by establishing a link with DNA high-force mechanics. The results open up the study in the completely unexplored area of the principally anomalous kinetically trapped DNA surface conformations in which the DNA local mechanical response to the surface-induced spatially modulated lateral electrostatic stress is essentially nonlinear. The underlying rich and complex in-plane nonlinear physics acts at the nanoscale beyond the scope of applicability of the worm-like chain approximation. [ABSTRACT FROM AUTHOR]

The effect of addition of J-aggregates of polymethine dye into the hole-transport layer of an organic light-emitting diode (OLED) on its characteristics and operational stability was studied. Water-soluble PEDOT:PSS (poly(3,4-ethylenedioxythiophene)) and the interpolymer complex of polyaniline and poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAn-PAMPSA) were used as the matrices of polymer nanocomposites. The highest efficiency characteristics of the OLEDs with the considered structure were achieved using PAn-PAMPSA at a particular component ratio in the interpolymer complex. Additives of J‑aggregates did not significantly affect the efficiency characteristics of the OLEDs; however, an increase in the operational stability of devices was recorded. [ABSTRACT FROM AUTHOR]

We present the comparative study of the analytical forward model and the statistical simulation of the Compton single scatter in the positron emission tomography. The formula of the forward model has been obtained using the single scatter simulation approximation under simplified assumptions, and therefore we calculate scatter projections using independent Monte Carlo simulation mimicking the scatter physics. The numerical comparative study has been performed using a digital cylindrical phantom filled in with water and containing spherical sources of emission activity located at the central and several displaced positions. Good fits of the formula-based and statistically generated profiles of scatter projections are observed in the presented numerical results. [ABSTRACT FROM AUTHOR]

Collective near‐field effects in perspective 2D materials containing semiconductor quantum emitters can be used to design novel devices for light manipulation on the nanoscale. The present paper considers an energy conversion from the pump laser field to the surface plasmon polaritons (SPPs) on the base of the hybrid optoplasmonic multi‐level scheme of near‐resonant interaction with semiconductor quantum dots (QDs) placed in the proximity of a graphene surface. Using numerical simulations and semiclassical approach for the light–matter interaction, it is shown that maximum efficiency of SPP generation is achieved in strong coupling conditions for a stationary regime of SPP‐QD interaction. Besides, the conditions for observation of SPP collective resonances in an ordered array of optically excited QDs placed above graphene are determined. Finally, the use of the constructive SPP interference regime in a meta‐layer of QDs above graphene for efficient near‐field amplification and subwavelength light concentration is proposed and discussed. [ABSTRACT FROM AUTHOR]

We construct some counterexamples to the statements [1, 2.3.6] claiming maximal inequalities for the spaces and and propose a condition for these inequalities to hold. We consider some weighted inequality on a bounded interval of the real axis that involves and the derivative of . [ABSTRACT FROM AUTHOR]

Problems requiring high-precision comparisons and synchronization of time scales (TS) of remote time and frequency standards are analyzed. The prospects of using fiber-optic communication lines to solve these problems are considered. Data on maximum operating distances and accuracy characteristics of TS comparison systems using fiber-optic communication lines are given. It is shown that the range of existing systems is not sufficient for solving a number of relevant problems. A method for amplifying optical signals in an optical fiber using the stimulated Raman scattering (SRS) effect is proposed. The application of the Raman amplifier in telecommunication systems is considered. A method is suggested for using SRS to amplify the optical signals of TS comparison systems. A scheme is proposed for a system of one- and two-way TS comparisons of distant objects using signal amplification based on the SRS effect realized using two-way counter-pumping. The operational principle of the system is described along with the procedure for determining the divergence in the TS of remote objects. The results of estimating the error and range of systems of one- and two-way comparisons of time scales using the Raman amplifier are presented. It is shown that the implementation of Raman amplification in the equipment of such systems will allow their range to be increased by more than three times without reducing system accuracy. [ABSTRACT FROM AUTHOR]