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We describe the growth, material characterization, and lasing of InP/GaInP quantum dot (QD) microdisks (diameter D = 2.2 μ m, quality factor Q ∼ 9000) with an emission lasing line of 693 nm (77 K). We demonstrate that MOVPE growth can result in two types of InP/GaInP QDs, differing in height (type A h ∼ 5 –10 nm, type B h ∼ 20 nm), whose emission has different decay lifetimes (τ A = 0.6 ns, τ B = 2.4 ns). We show, importantly for technological microlasing applications, that lasing occurs via the excited states of type A QDs, as inferred from a number of experimental results: power-dependent photoluminescence, time-resolved experiments, and temperature dependence of the generation threshold. [ABSTRACT FROM AUTHOR]

Experiments on the growth of self-assembled InP/GaInP2 quantum dots in dielectric mask 0.1–1 μm apertures by MOVPE epitaxy have been carried out. A sequence of operations for the implementation of the lift-off lithography method is proposed and implemented. The possibility of obtaining apertures with 100 nm diameter and less is shown. Combination of thermally deposited SiO2 and wet etching is shown to produce minimal amount of nonradiative defects and results in a stable PL signal from single QDs in the aperture. [ABSTRACT FROM AUTHOR]

A method has been developed to obtain composite membranes based on porous glass. Inside the nanopores of glass membranes, gold nanoparticles are formed that have plasmon resonance. The average size of the obtained particles was 20–25 nm. The obtained membranes are promising for the development of new-generation sensors and investigation of the impact of plasmon resonance effect on ion transport inside nanopores. [ABSTRACT FROM AUTHOR]

Determination of the mechanism of action of potential medicinal substances is an integral stage in development of novel drugs. The interaction of antiviral peptide PB16–14 with lipid membranes in cell and cell-free model systems is demonstrated. Penetration of a fluorescently tagged analog of peptide into cells has been observed for 15 min using continuous-flow cytofluorometry and confocal microscopy. The specific features of interaction of the peptide under study with cell membranes have been studied using small-angle neutron scattering (SANS), atomic force microscopy (AFM), and dynamic light scattering. It is shown that model liposomes (PC/PG) increased in size in the presence of peptide (in a 5% ethanol/5% DMSO/PBS buffer), while the ζ potential changed only slightly, which can be interpreted as a consequence of a change in the surface charge and may indicate peptide ability to interact with a lipid bilayer (not excluding its penetration into the membrane). The data obtained can be used both for studying the mechanism of therapeutic peptide transport and for developing drug-delivery agents. [ABSTRACT FROM AUTHOR]

It is shown using small-angle X-ray scattering (SAXS) that the tetrapeptide, which is an inductor of fibrillogenesis for a fragment of α-human lactalbumin β-domain, is active in the form of supramolecular complexes. Formation of these complexes was not detected by microscopy and analytical gel filtration. Molecular-dynamics simulation of the behavior of an ensemble of tetrapeptides using the free diffusion method confirmed their experimentally observed tendency to form oligomers. The obtained data and methodical approaches can be applied to develop new peptide drugs, which can modulate the activity of proteins by affecting their spatial structure. [ABSTRACT FROM AUTHOR]

We used the measurements of the photo-luminescence spectra vs photon pumping and Coulomb blockade charge tuning together with Kelvin probe microscopy to study piezo-electric fields in self-organized InP/GaInP2 quantum dots (QDs) having a strong Wigner localization regime. These exciton/electron state-filling measurements together with the surface potential imaging and the band structure calculations demonstrate a piezo-electric doping and type-I optical transitions induced in these dots by an atomic ordering (AO) of GaInP2. Our results clarify a critical role of AO in the formation of natural Wigner and anyon molecules and represent an important step for realization of the topological quantum gates using these QDs. [ABSTRACT FROM AUTHOR]

The review describes the application of small-angle scattering (SAS) of neutrons and complementary methods to study the structures of biomacromolecules. Here we cover SAS techniques, such as the contrast variation, the neutron spin-echo, and the solution of direct and inverse problems of three-dimensional reconstruction of the structures of macromolecules from SAS spectra by means of molecular modeling. A special section is devoted to specific objects of research, such as supramolecular complexes, influenza virus nucleoprotein, and chromatin. [ABSTRACT FROM AUTHOR]

Various methods of synthesis of CuInSe2 remain relevant because it is one of the most effective materials for solar energy. An effective method for the preparation of the CuInSe2 nanodispersed selenium precursor for microwave synthesis is considered. Colloidal selenium solutions were obtained using laser ablation in various liquid media: water, ethanol, triethylene glycol, polyethylene glycol–400 (PEG-400), and a 1% solution of PEG-1500 in PEG-400. The optical properties of the obtained colloidal selenium solutions were studied. Electron microscopy of selenium particles was conducted. Trends of ablation rate change and physicochemical properties of dispersed selenium particles in the variety of liquid media listed above are discussed. The possibility of synthesizing CuInSe2 using the obtained precursor was verified. [ABSTRACT FROM AUTHOR]

The article considers the problem of calculation and evaluation of the efficiency of industrial apparatus, meaning in particular the columns of pulsation type. A numerical calculation method for determining the main hydrodynamic characteristics of the pulsating crystallizer is proposed. Numerical results are obtained for analyzing the pulsation mode and determining the possibility of improving the design of the crystallizer. Recommendations for improving the operation of the crystallizer are given. [ABSTRACT FROM AUTHOR]

We used transmission electron microscopy, Raman, and photoluminescence spectroscopy to identify the effect of CuPt-type GaP-InP atomic ordering (AO) on the structural and emission properties of self-organized (SO) InP/GaInP2 Wigner molecule (WM) quantum dot (QD) structures. We found that the correlation of AO and SO growth results in the formation of InP/GaInP2 QD/AO-domain (QD/AOD) core-shell composites. This observation shows that intrinsic WMs in this system emerge due to a strong piezoelectric field generated by AODs, which induces QD doping and a built-in magnetic field. We found that the bond relaxation of AODs leads to a decrease in the emission energy of WMs of 80 meV. The photoluminescence spectra of single WMs having an emission energy ∼1.53 eV are presented here, the lowest one reported for this system. [ABSTRACT FROM AUTHOR]

Laser-induced deposition of metals from a solution has been used as a new method for the synthesis of microcomposite materials in the copper-silver system. It was shown that the obtained materials have good sensory properties with respect to the determination of d-glucose in aqueous solutions. It is also shown that it can be used for gas sensors. Control of sensory properties can be done by changing the method of deposition. X-ray diffraction, EDX, and impedance spectroscopy were used to characterize the materials obtained and it was shown that laser sequential deposition and coprecipitation of two metals give different results. An explanation of the results was proposed. It explains them by the eutectic nature of the interaction in the copper-silver system. [ABSTRACT FROM AUTHOR]

The possibilities of laser-induced liquid phase chemical deposition (LCLD) of metal for continuous generation of nickel nanoparticles, the sizes of which allow their use as a catalyst for organic reactions are considered. The conditions for obtaining Ni nanoparticles by this method were optimized. [ABSTRACT FROM AUTHOR]

Abstract: We report a realization of room temperature lasing threshold of 1 μW in GaInP microdisk containing a few self-aggregated InP/GaInP quantum dots (QDs) grown by metal-organic vapor phase epitaxy. InP/GaInP QD microdisk cavities emitting in the spectral range of 700-800 nm and having the size of ~2 μm, free spectral range of ~35 nm and quality factors Q ~ 4000 were formed by wet chemical etching. Low dot density (~2 μm-2) and large dot size (~150 nm), suggesting a single dot lasing and maximum overlap of QD and cavity mode, were achieved using deposition of 3 ML of InP layer at 700°C. [ABSTRACT FROM AUTHOR]

The effect of an external electric field on the ionic conductivity and selective properties of ceramic membranes based on alumina nanofibers coated with a conductive carbon layer has been studied. It has been shown that the membranes are ideally polarizable in the polarizing voltage range of −500 to +500 mV and, therefore, can be used for implementing switchable ionic selectivity. Experiments have revealed that the membrane resistance decreases with a change in the applied potential from 0 to ±500 mV. It has been shown that the membrane selectivity can be switched from anion to cation by varying the external potential. The surface charge density of the membranes has been determined in terms of the Teorell-Meyer-Sievers model according to the experimental measurements of the membrane potential. [ABSTRACT FROM AUTHOR]

We investigated structural and emission properties of self-organized InP/GaInP quantum dots (QD) grown by metal organic chemical vapor deposition using an amount of deposited In from 7 to 2 monolayers (ML). In the uncapped samples, using atomic force microscopy (AFM), we observed lateral sizes of 100-200 nm, together with a bimodal height distribution having maxima at ∼5 and ∼15 nm, which we denoted as QDs of type A and B, respectively; and reduction of the density of the type-B dots from 4.4 to 1.6 μm-2. The reduction of the density of B-type dots were observed also using transmission electron microscopy of the capped samples. Using single dot low-temperature photoluminescence (PL) spectroscopy we demonstrated effects of Wigner localization for the electrons accumulated in these dots. [ABSTRACT FROM AUTHOR]

Formation, emission, and lasing properties of strain-free InP(As)/AlInAs quantum dots (QDs) embedded in AlInAs microdisk (MD) cavity were investigated using transmission electron microscopy and photoluminescence (PL) techniques. In MD structures, the QDs have the nano-pan-cake shape with the height of ~2 nm, the lateral size of 20-50 nm, and the density of ~5×109 cm-2. Their emission observed at ~940 nm revealed strong temperature quenching, which points to exciton decomposition. It also showed unexpected type-I character, indicating In-As intermixing as confirmed by band structure calculations. We observed lasing of InP(As) QD excitons into whispering gallery modes in MD having the diameter of ~3.2 lm and providing a free spectral range of ~27 nm and quality factors up to Q~13 000. Threshold of ~50 W/cm2 and spontaneous emission coupling coefficient of ~0.2 were measured for this MD-QD system. [ABSTRACT FROM AUTHOR]

An Erratum to this paper has been published: https://doi.org/10.1134/S1063774521340034 [ABSTRACT FROM AUTHOR]

Relaxation properties of polymer near-surface layers were investigated with the help of thermoluminescent method using Nanoluminograph (PlasmaChem GMbH, Germany). The gel- and melt-crystallized films from PE of different molecular weight were studied. The light sum of thermoluminescence in the temperature range of various relaxation transitions was compared. It is found that it is primarily controlled by the type of morphology forming during crystallization and the arrangement of the structural units on a surface. The glass transition temperature in near-surface layers appeared to be lower that that in the bulk. Bulk glass transition temperature was determined by radiothermoluminescence, DMA and DSC techniques. [ABSTRACT FROM AUTHOR]

The interaction of intermediate host ( Eogammarus tiuschovi) cells with the cysticercoid of Microsomacanthus lari of the cyclocercus type was examined for the case of damage of the noncellular exocyst surrounding it. Massive penetration of the host cells, supposedly haemocytes characterized by intensive secretion, into the exocyst was observed even during the first several minutes of the experiment. Large accumulations of the product of secretion (fibrous material) were concentrated in the distal areas of the endocyst glycocalix and the microvillar layer of the cysticercoid tail appendage. The results provide evidence for the defensive role of the exocyst of M. lari in the cellular response of an intermediate host organism to invasion. [ABSTRACT FROM AUTHOR]

Surface morphology of highly oriented pyrolytic graphite with electrodeposited nickel nanoparticles was studied by atomic-force microscopy in the presence and absence of ethanol. Voltammetric and atomic-force microscopic data and histograms of particle size distribution were used to evaluate the unit-area catalytic activity of the nanocatalyst in relation to conditions of its preparation. [ABSTRACT FROM AUTHOR]

A special probe with a 5-μm-diameter ball fixed at the end is developed for an atomic force microscope (AFM), with the use of which it is possible to obtain more correct values of the Young’s moduli of biological objects in liquid media and eliminate the risk of damaging the sample surface. In particular, the AFM measurements with this probe in situ revealed an increase in the Young’s modulus of rat blood vessel under the action of chlorhexidine. [ABSTRACT FROM AUTHOR]

The chromatin organization in chicken erythrocyte nuclei was studied by small-angle neutron scattering in the scattering-vector range from 1.5 × 10−1 to 10−4 Å−1 with the use of the contrast-variation technique. This scattering-vector range corresponds to linear dimensions from 4 nm to 6 μm and covers the whole hierarchy of chromatin structures, from the nucleosomal structure to the entire nucleus. The results of the present study allowed the following conclusions to be drawn: (1) both the chromatin-protein structure and the structure of the nucleic acid component in chicken erythrocyte nuclei have mass-fractal properties, (2) the structure of the protein component of chromatin exhibits a fractal behavior on scales extending over two orders of magnitude, from the nucleosomal size to the size of an entire nucleus, and (3) the structure of the nucleic acid component of chromatin in chicken erythrocyte nuclei is likewise of a fractal nature and has two levels of organization or two phases with the crossover point at about 300–400 nm. [ABSTRACT FROM AUTHOR]