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The optical characteristics of vertical cylindrical micropillars with AlGaAs distributed Bragg reflectors and InAs/GaAs quantum dots, which are designed for the fabrication of single-photon sources, have been studied. The effect of parameters such as the inclination angle of sidewalls, partial oxidation of AlGaAs layers, and deviation of quantum dots from the central axis of a micropillar on the Purcell factor and the radiation extraction efficiency has been numerically simulated by the finite-difference time-domain method. The allowable ranges of the listed parameters have been determined for cylindrical vertical 920-nm micropillars. The comparison of the calculations performed with the refined refractive indices of the used materials at cryogenic temperatures with the measured characteristics of the fabricated micropillar structures has confirmed the adequacy of the used models.

A method for forming composite electric arc coatings by using a modernized EM-14M spraying gun with a powder feed unit of free powder to a high-temperature heterophase jet during spraying is proposed. Samples of a metal-polymer composite coating of the composition steel Sv-08-G2S-O — polymer P-EP-219 were obtained. Experimentally established the necessary zone for the supply of polymer powder was to prevent its destruction in the high-temperature zone of the arc discharge and the optimal modes of deposition metal-polymer coatings: current 90…100 A, arc voltage 25 V, compressed air pressure 0,4…0,6 MPa, polymer powder consumption 25 g/min, spraying distance 100...120 mm. If these modes are observed, the conditions for the formation of a high-quality metal-polymer coating with a thickness of 0.5-0.8 mm with a maximum content of the polymer component of 40 %(vol.) are provided. A scanning electron microscope REMMA-102-02 was used to investigate the microstructure of the sprayed coatings. It has been established that the porosity of composite coatings is reduced from 13 % to 7 % in comparison with convention steel coatings. The phases were identified by determining their microhardness on cross sections with a load on the indenter of 50 g. It was found that the microhardness of the metal matrix is 1716 MPa; polymer component — 128 MPa. It is shown that the deposited coatings are characterized by the presence on their surface of a continuous polymer film with a thickness of 10 to 100 μm, which is formed as a result of the fact that the polymer solidifies later than the crystallization of metal particles. It has been experimentally confirmed that the thermal conductivity of metal-polymer coatings deposited from the SV-08G2S-O – P-EP-219 composition decreases by 46 % in comparison with the thermal conductivity of convention coatings from SV-08G2S-O wire. The proposed coatings are recommended to be used as anticorrosion and heat-insulating coatings on various structures due to the thin surface polymer film and low thermal conductivity.

An investigation has been performed of 1.55-μm vertical-cavity surface-emitting lasers based on heterostructures with a buried tunnel junction (BTJ) with a height difference of 15 nm. The devices are obtained by wafer fusion of heterostructures grown by molecular beam epitaxy and provide single-mode lasing at a BTJ diameter of up to 8 μm. A decrease in the BTJ size leads to a sharp increase in the threshold current, the output optical power, and the resonance frequency at the lasing threshold. Stable single-mode lasing takes place due to the smoothed boundary of the buried surface relief, which induces a gradual change in the profile of the effective refractive index in the lateral direction with the effective current confinement retained. This makes it possible to reduce significantly the transverse optical confinement factor for the higher-order modes even at a large BTJ size. However, at a small BTJ size, it leads to the formation of a saturable absorber in unpumped parts of the active region.

Conversion of waste heat into usable electricity is a strategic technology for saving natural resources and an important option for powering autonomous devices. Current developments in micro- and n...

The results are presented of a study and optimization of the conditions under which heterointerfaces of the GaAs–InGaAsP type are formed via the direct intermolecular wafer bonding (fusion) of a heterostructure of an active region on an InP substrate and distributed Bragg reflectors on GaAs substrates upon the fabrication of hybrid heterostructures for long-wavelength vertical-cavity surface-emitting lasers (VCSELs). The heterostructures are grown by solid-source molecular-beam epitaxy. It is shown that, in the case of the incomplete removal of oxide films during preparation of the wafers before fusion and/or in the presence of adsorbed water on the wafer surfaces, the fused interface contains a large number of amorphous inclusions, which are most likely oxides of Group-III elements. Optimization of the conditions in which a buried tunnel junction is formed on the surface of the heterostructure on an InP wafer made it possible to reduce the surface roughness to 1 nm and to ensure that the thickness of the GaAs–InGaAsP fused interface does not exceed 5 nm, with no dislocations or other extended defects found at the fused heterointerfaces. The 1.55-μm VCSELs fabricated from the hybrid heterostructures created using the developed technology demonstrate efficient lasing under continuous-wave pumping in a wide temperature range, which is indicative of the high optical quality of the fused heterointerfaces in the VCSEL structure.

Objective: to develop technology for high amputations of the lower extremities.Materials and methods.We analyzed the materials of the Nizhny Novgorod branch of the Federal State Unitary Enterprise “Moscow Orthopedic and Orthopedic Enterprise” Ministry of Labor of Russia for the period 2004–2018, the operation logs of the purulent surgery department of PIMU (1971–2018), and the electronic medical history “Program 1C” (2006–2012) and “Medialogue” (2013–2018) in all departments of PIMU, where high amputations of the lower extremities are possible performed.Results.Between 2006 and 2018, 391 lower limbs were cut off in 289 patients (above the knee – 128, below the knee – 263). With diabetic foot syndrome, 135 (34.5 %) amputations were performed, due to burns and frostbite, 73 (18.7 %) operations were made, while arterial atherosclerosis – 57 (14.6 %) operations, and the rest – about the consequences of injuries, tumors, malformations and vicious stumps. The number of amputations on the shin is 2 times more than on the hip. A technology has been developed for the formation of a new support and movement organ, including amputation of the lower leg, anesthesia, intensive care, and rehabilitation treatment.Conclusion. An analysis of the initial applications for prosthetics showed that the most frequent high amputations of the lower extremities are performed due to gangrene in arterial atherosclerosis (53.9 %) and diabetes mellitus (24.9 %). High amputations of the lower extremities at the hip level are performed in 60.4 % of patients and only in 30.1 % of patients – at the shin level. Malformations and diseases of the stumps of the thigh and lower leg are detected in 15.4 % of patients. The gold standard should be recognized as myoplastic amputation at the border of the upper and middle third of the shin with excision of the soleus muscle. Preservation of the knee joint creates the conditions for optimal prosthetics and timely social adaptation of patients.

A design of a tunnel junction (TJ) based on n++-InGaAs/p++-InGaAs/p++-InAlGaAs layers for vertical-cavity surface-emission lasers (VCSELs) for the 1.55-μm spectral range fabricated by wafer fusion of an InAlGaAsP/InP optical cavity and wafers with AlGaAs/GaAs distributed Bragg reflectors has been suggested and tested. The presence of the oxidation-resistant InGaAs layers makes it possible to employ the molecular-beam epitaxy in all stages of the fabrication technology of VCSELs, including the overgrowth of the surface profile in the TJ layer. Owing to the Burstein–Moss effect and to the thickness minimization of the p++-InGaAs layer, it was possible to avoid a buildup of the internal optical loss. As a result, the characteristics of the thus fabricated devices are comparable with those of VCSELs having an n++-/p++-InAlGaAs TJ and a similar level of the mirror losses.

We present a numerical model suitable for simulation of shock or blast waves passing through a cloud of water droplets. The model takes into account the droplet breakup, radiation, and evaporation effects. The gas phase (a mixture of air and water vapor) is solved within an Eulerian framework with a set of compressible transport equations. The disperse phase (water droplets) is represented by a number of Lagrangian parcels of a specified size and mass distribution. The model has been verified with experimental data. The results show that for large (millimeter-sized) droplets with high Weber numbers, the breakup model is the most important part for accurate representation of the wave-droplet interaction phenomena, while for very fine droplets (1 $$\mu$$ m or less), the evaporation effects are the strongest in the shockwave mitigation process. The radiative heat flux increase due to high droplet emissivity is found to be possible for an intermediate size water droplets (about 10–20 $$\mu$$ m) in the case of continuous heat release.

The article presents the results of direct numerical simulation of a turbulent vortex ring with a moderate Reynolds number, interacting with the field of external turbulent fluctuations. The ring is formed by buoyancy forces from a spherically-shaped volume of elevated temperature. We consider the interaction of the ring with the field of turbulent fluctuations (of temperature and velocity) located in the form of a horizontal layer in front of the ring. The effect of separation of vortices by the sign of vorticity in a layer of fluctuations (with respect to the rotation of the ring) during the passage of the ring through this field has been found. This effect first causes the ring to slow down when the fluctuations pass outside the ring, and then to accelerate with decreasing radius when the fluctuations pass through its center. Due to buoyancy effects in the fluctuations layer, the separation of hot and cold air occurs. During the interaction with the ring, this leads to the accumulation of the reduced temperature in the core of the ring, while the increased temperature is accumulated near the axis. This temperature distribution results in a baroclinic vorticity generation leading to the reduction of the ring radius.

A high-electron-mobility transistor (HEMT) based on InAlAs/InGaAs/InP heterostructures possessing higher breakdown characteristics is developed. An InGaAs composite channel structure, combined with completely selective forming of the double recess structure, is used in the devices. HEMTs with a T‑shaped gate 120 nm in length consist of four fingers, each 30 μm in width, exhibit a maximum transconductance of 810 mS/mm, 460-mA/mm maximum density of drain current and 8- to 10-V drain-to-gate breackdown voltage. The current-amplification cut-off frequency of transistors is over 115 GHz. Due to the enhanced breakdown voltage and the forming of a double recess structure by selective etching, the elaborated transistors are promising for application in the monolithic integrated circuits of the millimeter-wave medium power amplifiers.

Optimum shape of the capacitance–voltage (C–V) characteristic is a critical parameter determining the efficiency of frequency multiplication in heterobarrier varactors (HBVs) operating in the millimeter and submillimeter frequency ranges. A numerical model for calculating the C–V characteristics and leakage currents of HBV heterostructures with arbitrary composition and doping profiles has been verified on the basis of published and original experimental data. A specially designed HBV heterostructure with three undoped InAlAs/AlAs/InAlAs barriers surrounded by nonuniformly doped n-InGaAs modulation layers has been grown by molecular beam epitaxy on InP substrate. Prototype HBVs manufactured using the proposed heterostructure demonstrated a nearly cosine shape of the C–V curve at bias voltages up to 2 V, increased overlap capacitance, and low leakage currents.

The results of studying the dynamic characteristics of 1.55-μm single-mode vertical-cavity surface-emitting lasers (VCSELs) formed by the fusion of wafers of high-quality Bragg reflectors and an active region based on thin highly strained InGaAs/InAlGaAs quantum wells are presented. It is found that the proposed design of the active region and optical microcavity of the laser make it possible in principle to attain a high level of differential laser gain in the temperature range of 20°C–85°C, but weak electron localization leads to an increase in gain compression at elevated temperatures. Due to this fact, the VCSEL modulation bandwidth at 20°C can be increased from 9.2 to 11.5 GHz due to an increase in output optical losses, while the modulation bandwidth at 85°C does not exceed 8.5 GHz, depends weakly on the output optical losses, and is mainly limited by the optical-gain saturation.

The results of a study of internal optical losses and current injection efficiency in vertical-emitting lasers of a spectral range of 1.55 µm obtained by sintering plates of high-q Bragg reflectors and the active region on the basis of thin strained InGaAs/InAlGaAs quantum wells have been presented. It has been shown that the proposed design of the laser provides a record low level of internal optical losses (less than 6.5 cm–1) and high efficiency of current injection (more than 90%) at room temperature, which allows the realization of submilliampere threshold currents. As the temperature rises to 85°C, the current injection efficiency drops to 70% due to the thermal emission of charge carriers from the active region, accompanied by an increase in internal optical losses to 9.1 cm–1 because of an increase in absorption on free carriers and/or intersubband absorption in the valence band.

The early period of postnatal development of premature infants is often complicated by bacterial infections, in particular respiratory infections, which in adverse course can be transformed into generalized forms (sepsis), leading to life-threatening conditions. The development of these complications may be associated with delayed diagnosis and delayed start of targeted therapy. Thus, the development of new approaches to the diagnosis of inflammatory pathological processes, especially in the first hours of life, is an important area of research in modern neonatology. In this work the profiling of blood plasma lipids from newborn premature babies was performed in order to identify potential markers of inflammatory processes. The study involved three groups of patients who were diagnosed with pneumonia, pneumonia complicated by sepsis, or respiratory distress syndrome in the early postnatal period. As a result of HPLC-MS analysis of blood plasma lipid extracts, characteristic molecular profiles were obtained, which revealed significant differences between the groups under study. Analysis of the molecular composition showed differential representation of lipid classes such as phosphatidylcholines, phosphatidylethanolamines, di- and triglycerides, sphingolipids and lysophospholipids. Our results may indicate that the inflammatory processes at the local and systemic levels affect lipid metabolism and their composition in blood plasma. Moreover, each pathology—sepsis, pneumonia or RDS—has its own specific lipid profile, which may be useful not only to detect inflammation but also to differentiate inflammation-associated diseases from each other.

© 2021 Optica Publishing Group. Users may use, reuse, and build upon the article, or use the article for text or data mining, so long as such uses are for non-commercial purposes and appropriate attribution is maintained. All other rights are reserved. A combination of advanced light engineering concepts enables a substantial improvement in photon extraction efficiency of micro–cavity–based single–photon sources in the telecom O–band at ∼1.3 µm. We employ a broadband bottom distributed Bragg reflector (DBR) and a top DBR formed in a dielectric micropillar with an additional circular Bragg grating in the lateral plane. This device design includes a doped layer in pin–configuration to allow for electric carrier injection. It provides broadband (∼8–10 nm) emission enhancement with an overall photon–extraction efficiency of ∼83% into the upper hemisphere and photon–extraction efficiency of ∼79% within numerical aperture NA=0.7. The efficiency of photon coupling to a single–mode fiber reaches 11% for SMF28 fiber (with NA=0.12), exceeds 22% for 980HP fiber (with NA=0.2) and reaches ∼40% for HNA fiber (with NA=0.42) as demonstrated by 3D finite–difference time–domain modeling.

We propose a hybrid microcavity design of a 1.3 μm range electrically driven single-photon source (SPS) consisting of two high-contrast dielectric distributed Bragg reflectors which surround a 3λ-thick semiconductor cavity with two intra-cavity contact layers and four 40-nm-thick oxide-confined apertures. According to 3D finite-difference time-domain modelling, the overall photon-extraction efficiency of ~74% and the Purcell factor of ~13 can be obtained by properly adjusting the position of oxide-confined apertures relative to the electric field of the fundamental optical mode. The studied SPS design also demonstrates a coupling efficiency of up to 13% within numerical aperture 0.12 in contrast to ~5% reached for a conventional semiconductor micropillar.

The most prevalent skin cancer in the transplant organ recipients is squamous cell cancer, followed by basal cell cancer. The skin cancer incidence and related mortality in the transplant organ recipient are significantly higher than those in the general population, which is to be linked with prolonged pharmaceutical immunosuppression. Multiple tumors are also typical for this patient group. The article describes two rare combinations of skin carcinomas with different histological characteristics in patients with cadaver renal allograft (CRA). Clinical case 1: A 43-year old female patient. In 2011, she was transplanted with a CRA due to end-stage renal failure caused by congenital cystic dysplasia (multicystic kidney disease), with subsequent removal of the allograft at 1.5 months after the transplantation. In 2014, she had her second CRA transplanted and until now is on immunosuppressive therapy. In 2013, the patient noticed two slowly growing masses in her right and left supraclavicular areas; they were clinically assessed as basal cell cancer and surgically resected. Histological examination of the resected skin fragments showed squamous cell carcinoma focuses in situ (Bowen's disease), with alternating superficial basalioma focuses; proliferating keratinizing squamous cell cancer with polymorphous structure, with prevailing acantholytic type, morphoeic basal cell carcinoma and basal squamous cell carcinoma were found throughout the dermal layer, up to the subcutaneous tissue. Clinical case 2: A 63-year old male patient was transplanted with CRA in 2007, due to end-stage renal failure caused by nephrolithiasis and chronic pyelonephritis. During the examination performed in 2013, a mushroom-like tumor (with a 3 cm diameter and a stipe of 1 cm in diameter, with erythematous tuberous surface) was found on the anterior neck surface, near the suprasternal notch. The tumor was surgically resected within the normal skin. Histological and immunochemical examinations showed that the mass consisted of two different tumors closely adjacent one to the other and separated by a narrow dermal layer, namely, neuroendocrine Merkel cell skin carcinoma and porocarcinoma with some signs of squamous cell and sebaceous cell differentiation.Conclusion: The descriptions of the rare cases confirm that transplantation-related skin cancers are highly relevant. Due to continuous renewal of the tissue components that is intrinsic to this organ, and due to deterioration of the immune control over proliferation and differentiation, they are characterized by a multiplicity of histological types and an unfavorable prognosis.

Vertical-cavity surface-emitting lasers (VCSELs) of 895 nm spectral range, with fixed direction of output polarization have been developed. These lasers provide single-mode output power of over 1 mW at an operational temperature of 60°С, at orthogonal polarization suppression ratio (OPSR) about 20 dB. The designed VCSELs were used in a laser source for a perspective compact nuclear magnetic resonance gyroscope. The designed laser source provides precise tuning of wavelength to the Cs133 D1 spectral line, and formation of collimated output beam.

The paper presents a simplified numerical model of the hydrogen plasma generation process in a microwave resonant cavity. The model assumes electroneutrality and the prescribed electron temperature of the plasma, thus significantly reducing the computational cost. This allows for the parametric study in a wide range of operating pressures end electric field magnitudes (at a frequency of 2.45GHz). The prescribed model allows finding the effective range of operating pressures for the plasma generation. At low pressures, the collision rate is too low to effectively absorb all the emitted energy while at high pressures the electron conductivity drops which also reduces the absorption efficiency.

The paper presents the results of optimization of the geometric parameters of the simplified wall jet cooling system using a modified Adjoint Shape optimization method for algebraic systems of equations (Discrete Adjoint Optimization). The modification consists in using a linearized discrete system of equations with the replacement of derivatives by their finite-volume approximations. The jet flowed through a duct and out from a nozzle. The duct was inclined at an angle of 35 degrees to the cooled wall. The mean velocity ratio between the jet and the main flow was set to 2. The total heat flux on the cooled wall was taken as a cost function. The problem was considered in a two-dimensional stationary turbulent formulation (RANS). As a result of optimization, the shape of the duct changed significantly, affecting the flow inside it. The optimization led to the disappearance of the recirculation zone and reattaching of the jet to the cooled wall. As a result of the optimization performed, the heat flux at the wall increased by 20%.

The article presents a simplified numerical simulation of a vacuum ferroelectric cathode operating in a low-current mode (without surface plasma formation). The field emission from the cathode was simulated for the range of applied electric field magnitudes. The polarization domain growth process during the charging of ferroelectric surface was simulated using Landau-Ginzburg-Devonshire model. Interaction of the electrons with a depolarization field of a domain wall led to an attraction of the electrons to the polarization domain boundaries. A close to the linear dependence of the equilibrium domain wall position from the applied electric field was found with the total emitted charge proportional to the domain size.

The main problems of providing a high-speed operation semiconductor lasers with a vertical microcavity (so-called “vertical-cavity surface-emitting lasers”) under amplitude modulation and ways to solve them have been considered. The influence of the internal properties of the radiating active region and the electrical parasitic elements of the equivalent circuit of lasers are discussed. An overview of approaches that lead to an increase of the cutoff parasitic frequency, an increase of the differential gain of the active region, the possibility of the management of mode emission composition and the lifetime of photons in the optical microcavities, and reduction of the influence of thermal effects have been presented. The achieved level of modulation bandwidth of ∼30 GHz is close to the maximum achievable for the classical scheme of the direct-current modulation, which makes it necessary to use a multilevel modulation format to further increase the information capacity of optical channels constructed on the basis of vertical-cavity surface-emitting lasers.

Vertical-cavity surface-emitting lasers (VCSELs) with an aperture limited by an oxide and a resonance cavity based on GaAlAs with high Al content provide a maximum γ factor (λ/2 design) and suppression of optical power beyond the aperture. A VCSEL with two coupled cavities provides additional sharp growth of the loss of high-order lateral modes by leakage to the oxidized region and provides single-mode laser generation for an aperture diameter of up to 5 μm. Single-mode antiwaveguiding VCSELs provide ultrafast data transmission with a rate of up to 160 Gbit/s. The structure in which the active medium is placed in the lower distributed Bragg reflector and the cavity and the upper distributed Bragg reflector are dielectric, reducing the temperature shift of the radiation wavelength by a factor of 2 (to ∼0.03 nm/K).

The emission-line width for 850-nm single-mode vertical-cavity surface-emitting lasers based on InGaAs/AlGaAs quantum wells is studied. The width of the emission line for a laser with a 2-μm oxide current aperture attains it minimum (~110 MHz) at an output power of 0.8 mW. As the optical output power is further increased, anomalous broadening of the emission line is observed; this is apparently caused by an increase in the α-factor as a result of a decrease in the differential gain in the active region under conditions of increased concentration of charge carriers and of high internal optical losses in the microcavity. The α-factor is estimated using two independent methods.

The studies of the emission linewidth for single-mode near-IR vertical-cavity surface-emitting lasers with an active region based on InGaAs/AlGaAs quantum wells and different optical microcavity design. For low mirror loss, lasers with a 1λ cavity and carrier injection through distributed Bragg reflectors demonstrate a linewidth of 70 MHz and its growth to 110 MHz with increasing mirror loss (corresponding differential of efficiency ∼0.65 W/A). The design of the optical cavity with carrier injection through intracavity contacts and low-Q composition Bragg lattices reduces the linewidth to 40 MHz in spite of high mirror loss (corresponding differential efficiency of ∼0.6 W/A).

We demonstrate noise characterization of novel 894.4 nm vertical-cavity surface emitting lasers with intracavity contacts and a rhomboidal oxide current aperture (IC-VCSELs), dedicated to 133Cs D1 line compact optically pumped atomic magnetometers (OPM). The laser relative intensity noise, measured to be -139 dB/Hz at 10 kHz frequency in 1 Hz bandwidth for a laser optical power of 0.8 mW, is decreased with optical power growth. The IC-VCSELs polarization-resolved relative intensity noise is 143 dB/Hz at 10 kHz frequency in 1 Hz bandwidth for 0.8 mW. The emission linewidth of the VCSEL is about 55 MHz. The IC-VCSEL parameters are determined, such as emission linewidth ~ 50-60 MHz, optical power ~ 0.5-1.0 mW, at which the polarization-resolved RIN becomes close to the RIN, which makes it possible to use these lasers in various OPM Mz and Mx schemes. The ultimate sensitivity of OPM was estimated by the ratio of the magnetic resonance to the signal to noise level. It is shown that a OPM based on the IC-VCSELs, assuming magnetic resonance FWHM ~ 1 kHz, can achieve a shot noise-limited sensitivity around 20 fT in 1 Hz bandwidth without any polarization improvements by polarizer or polarization beam splitter cube (PBC). Developed IC-VCSELs is acceptable for use in compact OPM for magnetoencephalography.

Neuroprotective properties of endocannabinoids N-arachidonoyl dopamine (NADA) and N-docosahexaenoyl dopamine (DHDA) were examined in neuronal precursor cells differentiated from human induced pluripotent stem cells and subjected to oxidative stress. Both compounds exerted neuroprotective activity, which was enhanced by elevating the concentration of the endocannabinoids within the 0.1-10 µM range. However, both agents at 10 µM concentration showed a marked toxic effect resulting in death of ~30% of the cells. Finally, antagonists of cannabinoid receptors as well as the receptor of the TRPV1 endovanilloid system did not hamper the neuroprotective effects of these endocannabinoids.

The molecular-beam epitaxy of InGaAs/InAlAs/AlAs structures for heterobarrier varactors is studied and optimized. The choice of the substrate-holder temperature, growth rate and III/V ratio in the synthesis of individual heterostructure regions, the thickness of AlAs inserts and barrier-layer quality are critical parameters to achieve the optimal characteristics of heterobarrier varactors. The proposed triple-barrier structures of heterobarrier varactors with thin InGaAs strained layers immediately adjacent to an InAlAs/AlAs/InAlAs heterobarrier, mismatched with respect to the InP lattice constant at an AlAs insert thickness of 2.5 nm, provides a leakage current density at the level of the best values for heterobarrier varactor structures with 12 barriers and an insert thickness of 3 nm.

Using the tissue-engineered constructs based on scaffolds that imitate the extracellular matrix of living tissues unveils new opportunities in the treatment of various pathologies and injuries associated with tissue and organ damage. Silk fibroin of silkworm Bombyx mori is a biocompatible and bioresorbable polymer with high mechanical strength and elasticity that allows creating scaffolds on its basis for regeneration of various tissues, including bone. In the present work, fibroin scaffolds were obtained. They were designed in the form of porous sponges, films, and hybrid scaffolds of a bilayer structure in which the porous sponge threedimensional structure is limited on one side by a film. The structure of the scaffolds and their biocompatibility were studied: immortalized and primary fibroblasts, as well as the osteoblast-like cells, have been shown to successfully adhere and proliferate on the surface of the studied scaffolds. Numerous osteogenesis foci have been observed in the implant region 4 weeks after the fibroin porous scaffold implantation in the in vivo experiments in a rat femoral bone defect model indicating the osteoconduction of the scaffolds.

The possibility of fabricating hybrid metamorphic heterostructures for vertical-cavity surfaceemitting lasers working in the 1300-nm spectral range is demonstrated. The metamorphic semiconductor part of the heterostructure with a GaAs/AlGaAs distributed Bragg reflector and an active region based on InAlGaAs/InGaAs quantum wells is grown by molecular-beam epitaxy on a GaAs (100) substrate. The top dielectric mirror with a SiO2/Ta2O5 distributed Bragg reflector is formed by magnetron sputtering. The spectra of the room-temperature microphotoluminescence of these vertical-cavity surface-emitting laser heterostructures are studied under 532-nm excitation in the power range of 0–70 mW (with a focused-beam diameter of ~1 μm). The superlinear dependence of the photoluminescence intensity on the excitation power, narrowing of the photoluminescence peaks, and a change in the modal composition may be indications of lasing. The results obtained give evidence that the technology of the metamorphic growth of heterostructures on GaAs substrates can be used for the fabrication of vertical-cavity surface-emitting lasers working in the 1300- nm spectral range.

Results of research on the effect of magnetization-curve approximation of the electrotechnical steel and excitation frequency of an asynchronous inverter-fed induction motor (IFIM) on its energy performance with extremal control algorithms based on energy-saving criteria are presented in this article. An IFIM is a variant of a double-fed motor with static frequency converters in the stator and rotor circuits. Its application in a variable-speed drive meets to the greatest extent the main requirements for an ac machine in terms of speed regulation and providing high energy performance. It is shown that application of piecewise linear approximation by three sections and the spline function provides improved values of energy performance relative to the simple approximation by two linear sections due to becoming close to a real magnetization curve. It provides, under otherwise equal values of electromagnetic torque, a higher flux linkage with decrease in magnetization current. Control of the excitation frequency of the asynchronous inverter-fed induction motor has a significant influence on the steel losses of the machine. In the region of low loads, they are particularly important relative to the active losses in the motor windings.

The applicability of UV spectroscopy to the quantitative determination of ribavirin in aqueous solutions was demonstrated. The existence of a third conformational form of ribavirin was found, and the optimization of three ribavirin conformers was performed using the nonempirical Kohn–Sham method. It was found that, regardless of the confirmation of ribavirin molecules, the absorption maximum of its aqueous solution corresponds to 206 nm.

A combination of advanced concepts is applied for designing micro-cavity structures aimed for single-photon sources with high photon-extraction efficiency in the telecom O-band at ~1.3 μm. The device design consists of a broad stop-band bottom distributed Bragg reflector (DBR), a top DBR formed in a dielectric micropillar with additional circular Bragg grating and a central dielectric passive cavity. This combination of photonic elements is compatible with electric carrier injection and provides overall photon-extraction efficiency of ~83% as shown by 3D finite-difference time-domain simulations.

The quality of heteroboundaries and optimal conditions for epitaxial growth are critical parameters for obtaining low leakage currents of heterobarrier varactors in the InGaAs/InAlAs/AlAs material system. Grown by molecular-beam epitaxy, three-barrier heterobarrier varactor structures adjacent to InAlAs/AlAs/InAlAs barrier layers by additional mismatched InGaAs layers subjected to compressive stress show, under optimal epitaxy conditions, extremely low levels of leakage current density (not more than 0.06 A/cm2 at a voltage of 5 V and 85°C) with relatively thin AlAs inserts (with a thickness of 2 nm).

The effects of composite fibroin-gelatin microparticles (100-250 μ) on the rate of wound healing and regeneration under conditions of contraction prevention were studied on the model of splinted full-thickness skin wound in a mouse. Subcutaneous injection of these particles into the defect area accelerated wound healing and promoted re-epithelialization and recovery of normal structure of the epidermis. In addition, the composite microparticles promoted the formation of connective tissue of characteristic structure, replacing the derma over the entire defect, and stimulated regeneration of subcutaneous muscle (panniculus carnosus) and skin appendages (sebaceous glands and hair follicles).

The aim of this study was to determine the changes of metabolomic profiles in embryonic culture media (ECM) for the evaluation of quality and implantation potential of human embryos. ECM (n=163) were collected on day 5 before transfer or cryopreservation. Some embryos were used in preimplantation genetic screening for detection of aneuploidy karyotypes. Samples were subdivided into groups according to embryo morphological classification (by Gardner), genetic analysis and implantation data. ECM were extracted with methanol, precipitates were separated by centrifugation and metabolite production of individual embryo was analysed by LC-MS (the positive ion mode). After peak detection and retention time alignment, data were analysed using the PCA algorithm. MS fingerprinting analysis of embryo culture medium showed significant differences between morphologically divided groups. Intragroup comparisons did not reveal differences between subclasses. Genetic screening of embryos revealed 33 aneuploid karyotypes. It was shown that chromosome number did not affect the metabolite profiles comparing with the normal group. The culture media of embryos that were positive or negative for successful implantation showed specific signatures that allowed to distinguish embryos with different outcomes.The characterization of ECMs by LC-MS may facilitate more accurate selection of the best embryo for the implantation, improving single-embryo transfer and thus eliminating the risk and undesirable effects of multiple pregnancies.Tsel'iu issledovaniia iavlialos' opredelenie izmeneniia profileĭ metabolitov v émbrional'nykh pitatel'nykh sredakh (ÉPS) dlia otsenki kachestva i implantatsionnogo potentsiala kul'tiviruemykh émbrionov cheloveka. ÉPS (163 sht.) byli sobrany na 5-ĭ den' do perenosa ili kriokonservatsii émbrionov. Chast' émbrionov voshla v programmu predimplantatsionnogo geneticheskogo skrininga s tsel'iu obnaruzheniia aneuploidnykh kariotipov. Obraztsy byli razdeleny na gruppy soglasno morfologicheskoĭ klassifikatsii émbrionov (po Gardneru) v sootvetstvii s dannymi geneticheskogo analiza i informatsii ob implantatsii posle perenosa. ÉPS ékstragirovali metanolom, osadok otdeliali tsentrifugirovaniem i produktsiiu metabolitov otdel'nykh émbrionov detektirovali s ispol'zovaniem VÉZhKh-MS v rezhime polozhitel'nykh ionov. Posle obnaruzheniia pikov i vyravnivaniia khromatogramm dannye obrabatyvali pri pomoshchi analiza glavnykh komponent (PCA). Profilirovanie metabolitov v ÉPS vyiavilo sushchestvennye razlichiia mezhdu morfologicheskimi klassami émbrionov. Vnutrigruppovye sravneniia ne obnaruzhili dostovernykh otlichiĭ mezhdu predstaviteliami odnogo klassa. Geneticheskiĭ skrining émbrionov vyiavil 33 anéuploidnykh kariotipa. Bylo pokazano, chto chislo khromosom ne vliiaet na profil' metabolitov po sravneniiu s normal'noĭ gruppoĭ émbrionov togo zhe klassa. V ÉPS implantirovavshikhsia i neimplantirovavshikhsia émbrionov byli vyiavleny spetsificheskie molekuliarnye signatury, pozvoliaiushchie differentsirovat' émbriony s raznym iskhodom implantatsii. Predpolagaetsia, chto profilirovanie metabolitov v ÉPS s pomoshch'iu VÉZhKh-MS mozhet sposobstvovat' bolee tochnomu otboru dlia perenosa odnogo émbriona s tsel'iu snizheniia riska nezhelatel'nykh posledstviĭ mnogoplodnoĭ beremennosti.