[Insomnia in neurological patients with disabilities]. / Insomniya u nevrologicheskikh bol'nykh s ogranichennymi vozmozhnostyami.

Sleep is the most important factor reflecting the level of psychophysical well-being of a person and influencing him/her to the same extent. The greater susceptibility to sleep disturbances in patients with disabilities is associated with numerous factors. In the existing literature, there are few studies of insomnia in people with neurological disabilities. This article presents a current view on sleep disorders in disabled people and methods for their treatment.

A sensitive and less cytotoxic assay for identification of proliferating T cells based on bioorthogonally-functionalized uridine analogue.

Quantitative detection of T cell proliferation is an important readout in immunology research, as it is one of the hallmarks of T cell activation. Fluorescence-based methods for T cell proliferation mostly rely on the usage of probes that non-specifically conjugate to free primary amine groups in cells. Each cell division then results in a two-fold dilution of the probes which is detectable with flow cytometry. However, questions have been raised about cytotoxicity of these dilution-based T cell proliferation probes and they potentially affect T cell activation. An alternative assay relies on the incorporation of the uridine analog BrdU in the DNA of dividing T cells that can be detected with an antibody, but this requires harsh fixation and denaturation conditions. Recently, a new assay for detection of cell proliferation has been developed, based on the incorporation of the bioorthogonally-functionalized uridine analog 5-ethynyl-2'-deoxyuridine (EdU). Goal of this study was to compare the sensitivity and cytotoxicity of the EdU assay with a widely-used dilution-based T cell proliferation probe, CellTrace Far Red. We found that, compared to the dilution-based probe, the EdU-based assay better preserves T cell viability, is more sensitive for detecting T cell proliferation, and allows for better discernable interferon gamma responses.

Fluctuation-induced free energy of thin peptide films.

We apply the Lifshitz theory of dispersion forces to find a contribution to the free energy of peptide films that is caused by the zero-point and thermal fluctuations of the electromagnetic field. For this purpose, using available information about the imaginary parts of the dielectric permittivity of peptides, an analytic representation for permittivity of a typical peptide along the imaginary frequency axis is devised. Numerical computations of the fluctuation-induced free energy are performed at room temperature for freestanding peptide films containing different fractions of water, and for similar films deposited on dielectric (SiO_{2}) and metallic (Au) substrates. It is shown that the free energy of a freestanding peptide film is negative and thus contributes to its stability. The magnitude of the free energy increases with increasing fraction of water and decreases with increasing thickness of a film. For peptide films deposited on a dielectric substrate, the free energy is nonmonotonous. It is negative for films thicker than 100nm, reaches the maximum value at some film thickness, but vanishes and changes its sign for films thinner than 100nm. The fluctuation-induced free energy of peptide films deposited on metallic substrate is found to be positive, which makes films less stable. In all three cases, simple analytic expressions for the free energy of sufficiently thick films are found. The obtained results may be useful to attain film stability in the next generation of organic microdevices with further reduced dimensions.

A Novel Fluorescent GFP Chromophore Analog-Based Dye for Quantitative PCR.

This is the first report describing the possibility of using a green fluorescent protein chromophore synthetic analog, P-HOBDI-BF2, as a fluorescent dye for a linear hydrolysis probe used in qPCR. The study was carried out on a system for detection of the plant pathogenic fungus Fusarium avenaceum using a plasmid containing translation elongation factor 1α fragment as a template. To estimate fluorogenic properties of P-HOBDI-BF2, 6-FAM- and BDP-FL-labeled probes were used. It was demonstrated that a synthetic dye based on the P-HOBDI-BF2 chromophore can be used for labeling hydrolysis probes for qPCR, but fluorescence increase levels for P-HOBDI-BF2-labeled probes were slightly lower than those for 6-FAM-labeled ones. At the same time, the sensitivity of P-HOBDI-BF2-based assays remained high, and this fact together with acceptable fluorescence levels suggests that this dye can be considered as an efficient alternative for reporters traditionally used for fluorescence detection in the FAM channel.

Theory of a Quantum Scanning Microscope for Cold Atoms.

We propose and analyze a scanning microscope to monitor "live" the quantum dynamics of cold atoms in a cavity QED setup. The microscope measures the atomic density with subwavelength resolution via dispersive couplings to a cavity and homodyne detection within the framework of continuous measurement theory. We analyze two modes of operation. First, for a fixed focal point the microscope records the wave packet dynamics of atoms with time resolution set by the cavity lifetime. Second, a spatial scan of the microscope acts to map out the spatial density of stationary quantum states. Remarkably, in the latter case, for a good cavity limit, the microscope becomes an effective quantum nondemolition device, such that the spatial distribution of motional eigenstates can be measured backaction free in single scans, as an emergent quantum nondemolition measurement.

Dark State Optical Lattice with a Subwavelength Spatial Structure.

We report on the experimental realization of a conservative optical lattice for cold atoms with a subwavelength spatial structure. The potential is based on the nonlinear optical response of three-level atoms in laser-dressed dark states, which is not constrained by the diffraction limit of the light generating the potential. The lattice consists of a one-dimensional array of ultranarrow barriers with widths less than 10 nm, well below the wavelength of the lattice light, physically realizing a Kronig-Penney potential. We study the band structure and dissipation of this lattice and find good agreement with theoretical predictions. Even on resonance, the observed lifetimes of atoms trapped in the lattice are as long as 44 ms, nearly 10^{5} times the excited state lifetime, and could be further improved with more laser intensity. The potential is readily generalizable to higher dimensions and different geometries, allowing, for example, nearly perfect box traps, narrow tunnel junctions for atomtronics applications, and dynamically generated lattices with subwavelength spacings.

Nanoscale "Dark State" Optical Potentials for Cold Atoms.

We discuss the generation of subwavelength optical barriers on the scale of tens of nanometers, as conservative optical potentials for cold atoms. These arise from nonadiabatic corrections to Born-Oppenheimer potentials from dressed "dark states" in atomic Λ configurations. We illustrate the concepts with a double layer potential for atoms obtained from inserting an optical subwavelength barrier into a well generated by an off-resonant optical lattice, and discuss bound states of pairs of atoms interacting via magnetic dipolar interactions. The subwavelength optical barriers represent an optical "Kronig-Penney" potential. We present a detailed study of the band structure in optical Kronig-Penney potentials, including decoherence from spontaneous emission and atom loss to open "bright" channels.

Self-adjusted all-dielectric metasurfaces for deep ultraviolet femtosecond pulse generation.

The advantage of metasurfaces and nanostructures with a high nonlinear response is that they do not require phase matching, and the generated pulses are short in the time domain without additional pulse compression. However, the fabrication of large-scale planar structures by lithography-based methods is expensive, time consuming, and requires complicated preliminary simulations to obtain the most optimized geometry. Here, we propose a novel strategy for the self-assembled fabrication of large-scale resonant metasurfaces, where incident femtosecond laser pulses adjust the initial silicon films via specific surface deformation to be as resonant as possible for a given wavelength. The self-adjusting approach eliminates the necessity of multistep lithography and designing, because interference between the incident and the scattered parts of each laser pulse "imprints" resonant field distribution within the film. The self-adjusted metasurfaces demonstrate a high damage threshold (≈1012 W cm-2) and efficient frequency conversion from near-IR to deep UV. The conversion efficiency is up to 30-fold higher compared with nonresonant smooth Si films. The resulting metasurfaces allow for the generation of UV femtosecond laser pulses at a wavelength of 270 nm with a high peak and average power (≈105 W and ≈1.5 µW, respectively). The results pave the way to the creation of ultrathin nonlinear metadevices working at high laser intensities for efficient deep UV generation at the nanoscale.

Extended Bose-Hubbard models with ultracold magnetic atoms.

The Hubbard model underlies our understanding of strongly correlated materials. Whereas its standard form only comprises interactions between particles at the same lattice site, extending it to encompass long-range interactions is predicted to profoundly alter the quantum behavior of the system. We realize the extended Bose-Hubbard model for an ultracold gas of strongly magnetic erbium atoms in a three-dimensional optical lattice. Controlling the orientation of the atomic dipoles, we reveal the anisotropic character of the onsite interaction and hopping dynamics and their influence on the superfluid-to-Mott insulator quantum phase transition. Moreover, we observe nearest-neighbor interactions, a genuine consequence of the long-range nature of dipolar interactions. Our results lay the groundwork for future studies of exotic many-body quantum phases.

A Method of Ground Simulation of Physiological Effects of Hypogravity on Humans.

A novel method of ground simulation in humans of physiological effects induced by the stay on the surface of celestial bodies with hypogravity was developed and successfully tested. This method is based on the change of gravity force angle, which decreases the gravitational component of the blood hydrostatic pressure characteristic of human vertical posture on the Earth and the load-weight onto the locomotor apparatus to the lower values expected at celestial bodies with hypogravity. The methodological requirements for ground simulation of the physiological effects of lunar gravity on human body are specified and substantiated by theoretical calculations. The experimental study revealed redistribution of liquid media in the human organism, functional changes in the cardiorespiratory system, and a decrease in the load-weight applied to the locomotor apparatus.

[Influence of simulated microgravity on the threshold of pain sensitivity in humans with single dose of ketorolac].

The data supporting the influence of simulated microgravity effects on pain sensitivity were obtained in the series of experiments involving human. In conditions of antiorthostatic hypokinesia (ANOH) and <> immersion revealed no reduction in pain sensitivity in the morning, which is typical for normal conditions. Ketorolac has no effect on pain sensitivity, when determining the pain threshold (PT) by method of thermoalgometry. However, the conditions of simulated microgravity substantially alter the pharmacokinetics of ketorolac, increasing the rate of absorption of the drug and reduce its relative bioavailability and retention time in the blood plasma. This may require changes in pain therapy schemes in space flight.

[Novel Water-Soluble Substrate for Silicateins].

We suggested to use tetrakis(2-hydroxyethyl)orthosilicate (THEOS) as a substrate for silicateins--an enzyme family playing a key role in formation of skeleton in marine sponges. We compared THEOS with tetraethylorthosilicate (TEOS)--a commonly used substrate for silicateins. These substrates were tested in reaction of amorphous silica formation in vitro catalyzed by silicatein Al from sponge Latrunculia oparinae. It was found that reaction with THEOS occurs more efficiently than with TEOS, probably due to high water solubility and higher hydrolysis rate of THEOS.

[Features of the pharmacokinetics of ceftriaxone during the antiorthostatic hypokinesia in rats].

This study was designed to investigate the effects of simulated microgravity on the plasma kinetics of ceftriaxone in rats. Comparative analysis of pharmacokinetic parameters in control and experimental groups has revealed the influence of antiorthostatic hypokinesia (ANOH) on the pharmacokinetics of ceftriaxone. Decreased level of maximum plasma concentration (C(max)) and bioavailability of ceftriaxone after single intramuscular (IM) injection were revealed in rats with antiorthostatic hypokinesia. The rate of absorption of the drug was higher respectively.

Polyphosphates and exopolyphosphatase activities in the yeast Saccharomyces cerevisiae under overexpression of homologous and heterologous PPN1 genes.

The role of exopolyphosphatase PPN1 in polyphosphate metabolism in fungi has been studied in strains of Saccharomyces cerevisiae transformed by the yeast PPN1 gene and its ortholog of the fungus Acremonium chrysogenum producing cephalosporin C. The PPN1 genes were expressed under a strong constitutive promoter of the gene of glycerol aldehyde-triphosphate dehydrogenase of S. cerevisiae in the vector pMB1. The yeast strain with inactivated PPN1 gene was transformed by the above vectors containing the PPN1 genes of S. cerevisiae and A. chrysogenum. Exopolyphosphatase activity in the transformant with the yeast PPN1 increased 28- and 11-fold compared to the mutant and parent PPN1 strains. The amount of polyphosphate in this transformant decreased threefold. Neither the increase in exopolyphosphatase activity nor the decrease in polyphosphate content was observed in the transformant with the orthologous PPN1 gene of A. chrysogenum, suggesting the absence of the active form of PPN1 in this transformant.

[Biochemical aspects of the influence of antiorthostatic hypokinesia on the experimental peritonitis].

Eighty white rats were divided into 4 groups: (1) vivarium control, (2) antiorthostatic hypokinesia (AH), (3) peritonitis alone, and (4) AH with peritonitis. Effects of AH were achieved by putting rats on a special stand for a period of 14 days, followed by the formation of peritonitis. After that biochemical parameters of blood samples have been investigated. Combination effects of microgravity and peritonitis is unidirectional and have mutual weights. As illustrated in some cases two-fold increase in the level of the studied parameters in comparison with the control and vivarium peritonitis. Comparative assessment of peritonitis severity revealed that simulated effects of microgravity turn the peritonitis into more complicated forms.

[Synthesis of the chromophores of fluorescent proteins and their analogs].

Members of the green fluorescent protein (GFP) family are widely used in experimental biology as genetically encoded fluorescent tags. Chromophores of GFP-like proteins share a common structural core: 3,5-dihydro-4H-imidazol-4-one. This review covers synthetic approaches to 3,5-dihydro-4H-imidazol-4-ones, substituted at different positions. General, as well as specific methods, represented by single examples are considered. The most popular synthetic route to substituted 3,5-dihydro-4H-imidazol-4-ones includes synthesis of azlactones, followed by transformation into N-acyldehydroaminoacids and, finally, cyclization into target heterocycles. Accordingly, the review is divided into three parts: the first part covers syntheses of azlactones, the second part covers main approaches to N-acyldehydroaminoacids, and in the third part we summarize cyclizations of N-acyldehydroaminoacids, as well as all other approaches to 3,5-dihydro-4H-imidazol-4-ones.

Majorana modes in driven-dissipative atomic superfluids with a zero Chern number.

We investigate dissipation-induced p-wave paired states of fermions in two dimensions and show the existence of spatially separated Majorana zero modes in a phase with vanishing Chern number. We construct an explicit and natural model of a dissipative vortex that traps a single of these modes, and establish its topological origin by mapping the problem to a chiral one-dimensional wire where we observe a nonequilibrium topological phase transition characterized by an abrupt change of a topological invariant (winding number). We show that the existence of a single Majorana zero mode in the vortex core is intimately tied to the dissipative nature of our model. Engineered dissipation opens up possibilities for experimentally realizing such states with no Hamiltonian counterpart.

[Physiological effects of microgravity as risk factors of diseases during space flight].

This paper considers to physiological effects of microgravity affecting different organs systems such as cardiovascular, neurohumoral, immune, and musculoskeletal systems. These physiologic changes suggest adverse influence with pathological processes during space flight and associated with high risk of morbidity of cosmonauts.

[Formation of spatial structure of RNA molecules].

In this review we consider several experimental and theoretical approaches for investigation of RNA folding and determination of nucleotides that play an important role upon folding of such molecules as tRNA and several classes of ribozymes. It has been shown that nucleotides in the D- and T-loop regions are the last to be involved in tRNA structure or they are not included in the folding nucleus of tRNA. Using the specially elaborated method SHAPE it has been demonstrated that the model of hierarchical folding which was recognized for a long time is not correct for tRNA folding. In the second part of the given review the algorithms and programs used for the prediction of secondary structures of RNA as well as for modeling of RNA folding are considered.