Russian Academy of Sciences
  • Moscow, Moscow, Russia
Recent publications
We observed huge, almost two orders of magnitude, increase in the energy of the forward terahertz (THz) emission by the long femtosecond filament if transverse electrostatic field is applied along its full length. This proves summation of emission both from different parts of a single filament and from multiple filaments. The observed THz radiation has a narrow angular shape with a maximum in the direction of laser radiation and a spectrum in the range of 0.05–0.3 THz with a maximum at about 0.1 THz. Numerical simulations based on the UPPE well explain the experimental findings.
Curcuminoids of boron difluoride, 1-aryl(hetaryl)-5-phenylpenta-2,4-dien-1-onates of boron difluoride, have been synthesized. A comparative study of the electronic structure, luminescent properties and their potential for applications in bio-imaging has been carried out. The influence of the electronic structure of α-substituents on the luminescence of compounds was studied by the methods of stationary and time-resolved luminescence spectroscopy and DFT modeling. The introduction of π-donor substituents leads to a noticeable bathochromic shift and an increase in the Stokes shift in the luminescence spectra. On going from σ-donor substituents in the phenyl ring to π-donor substituents, the luminescence quantum yield increases from 0.03 to 0.22. The maximum Stokes shift and high quantum yield of luminescence is exhibited by the complex with a stilbene substituent, which has the longest π-system and the maximum efficiency of charge transfer. Dyes are able to penetrate into the cells of the model cell line and accumulate, moreover, accumulation occurs mainly in the cytoplasm of cells. The compounds penetrate into the cells by 12 h of incubation without damaging it's structure and without causing rapid cell death. The submicromolar range of non-toxic concentrations during long-term incubation for a model cell line was determined, which is a characteristic of fluorescent imaging. Due to uniform distribution in the cytoplasm of cells dye with naphtyl substituent is promising for visualization of the cell cytoplasm. This leader compound has the lowest cytotoxicity for cells from the synthesized series of dyes, which makes it promising for further studies as a fluorescent imaging agent. The leader compound has the lowest cytotoxicity for cells from the synthesized series of dyes, which makes it promising for further studies as a fluorescent imaging agent.
The genus Methylomonas accommodates strictly aerobic, obligate methanotrophs, with their sole carbon and energy sources restricted to methane and methanol. These bacteria inhabit oxic-anoxic interfaces of various freshwater habitats and have attracted considerable attention as potential producers of a single-cell protein. Here, we characterize two fast-growing representatives of this genus, strains 12 and MP1T, which are phylogenetically distinct from the currently described Methylomonas species (94.0-97.3 % 16S rRNA gene sequence similarity). Strains 12 and MP1T were isolated from freshwater sediments collected in Moscow and Krasnodar regions, respectively. Cells of these strains are Gram-negative, red-pigmented, highly motile thick rods that contain a type I intracytoplasmic membrane system and possess a particulate methane monooxygenase (pMMO) enzyme. These bacteria grow between 8 and 45 °C (optimum 35 °C) in a relatively narrow pH range of 5.5-7.3 (optimum pH 6.6-7.2). Major carotenoids synthesized by these methanotrophs are 4,4'-diaplycopene-4,4'-dioic acid, 1,1'-dihydroxy-3,4-didehydrolycopene and 4,4'-diaplycopenoic acid. High biomass yield, of up to 3.26 g CDW/l, is obtained during continuous cultivation of MP1T on natural gas in a bioreactor at a dilution rate of 0.22 h-1. The complete genome sequence of strain MP1T is 4.59 Mb in size; the DNA G + C content is 52.8 mol%. The genome encodes four rRNA operons, one pMMO operon and 4,216 proteins. The genome sequence displays 82-85 % average nucleotide identity to those of earlier described Methylomonas species. We propose to classify these bacteria as representing a novel species of the genus Methylomonas, M. rapida sp. nov., with the type strain MP1T (=KCTC 92586T = VKM B-3663T).
In this study, fundamental aspects that have impact on the electroanalytical detection of hydrazine in phosphate, acetate and yeast fermentation medium in an analytically significant concentration range by several types of palladium (Pd)-modified electrodes, namely, Pd-ink, Pd-sputtered films and palladium nanoparticles (Pd-NPs) were systematically studied. The efficiency of hydrazine electrooxidation is not affected by the composition of multicomponent medium (i), presence of oxygen (ii), morphology or electroactive area (iii), but more likely depends on the purity degree of the electrode surface from residual palladium oxides (iv). In addition, using advanced methods of nanoanalytics and quantum chemistry, the crucial role of hydrazine surface adsorption (v) on oxide-free and oxide-based Pd-electrodes is highlighted. The obtained knowledge will provide future development strategies of electrodes based on nanoparticles of noble metals for tuned and efficient hydrazine electrooxidation in complex fermentation media.
Nikolai K. Koltzoff (Koltsov) (1872-1940) is one of the key figures in Russian biology. He essentially initiated Russian physicochemical biology and established a large scientific school in the area. Among his disciples, there are the geneticists B.L. Astaurov, S.S. Chetverikov, N.P. Dubinin, V.P. Efroimson, I.A. Rapoport, V.V. Sakharov, and N.V. Timofeeff-Ressovsky; histologist G.I. Roskin, experimental surgeon A.G. Lapchinsky, developmental biologist M.M. Zavadovsky, physiologist L.V. Krushinsky, microbiologist S.M. Gershenson, biochemist V.A. Engelhardt, hydrobiologist G.G. Vinberg, cytologist M.A. Peshkov, and many other famous Soviet biologists. He made several fundamental discoveries; the first of them was the discovery of the cytoskeleton (1903). He was the first to formulate the idea of a crystal-like mechanism for copying inherited information (1927) and the principles of epigenetics (as well as the term itself, in 1934; it seems astonishing, but as early as 1915, he hypothesized that the gene methylation might be a mechanism of genetic variability). He started the work which later led his disciples V.V. Sakharov and I.A. Rapoport to the discovery of chemical mutagenesis. His research on sex regulation in silkworms was later successfully continued by B.L. Astaurov. Koltzoff encouraged S.S. Chetverikov, the entomologist, to study the genetics of natural Drosophila populations, which went on to form the basis of the Modern Synthesis reconciling Darwinian evolutionary theory and the Mendelian laws of heredity. Unfortunately, the name of N.K. Koltzoff has almost sunk into oblivion. This is largely due to the fact that mentioning his name was prohibited in the USSR over a long period of time, since he was a staunch opponent of Lysenko. In this paper dedicated to the 150th anniversary of Koltzoff, we briefly describe the milestones of the life and scientific research of this outstanding biologist and his scientific school.
In this study, acetic acid bacteria (AAB) are isolated from fruit waste and cow dung on the basis of acetic acid production potential. The AAB were identified based on halo-zones produced in the Glucose-Yeast extract-Calcium carbonate (GYC media) agar plates. In the current study, maximum acetic acid yield is reported to be 4.88 g/100ml from the bacterial strain isolated from apple waste. With the help of RSM (Response surface methodology) tool, glucose and ethanol concentration and incubation period, as independent variable showed the significant effect of glucose concentration and incubation period and their interaction on the AA yield. A hypothetical model of artificial neural network (ANN) was also used to compare the predicted value from RSM. Acetic acid production through the biological route can be the sustainable and clean approach to utilizing food waste in circular economy approach.
The work is dedicated to further development of our described method for analyzing mass spectra of biomolecules acquired as a result of hydrogen-deuterium exchange reactions (HDXs). The modified method consists of separating HDX distributions via their approximations by a minimum number of components corresponding to independent H/D substitutions and independent charge carrier retentions in different spatial isoforms or conformations of biomolecules with unknown primary structures. In this case, neither the natural isotopic distribution nor the exact number of active sites involved in HDXs and H+ or D+ attachments can be determined in advance. Original H/D electrospray mass spectra of an apamin solution were taken from our previous work. In that work, taking into account the natural isotopic distribution of apamin molecules, three main conformations of apamin ions were found as a result of separating the H/D mass spectra of the apamin solution for the gas flow with the addition of about 10% ND3 molecules. Using the proposed modified method that does not require knowledge of the primary structure of the biomolecules gave similar results with slight deviations of calculated HDX distributions of the apamin ions from those obtained earlier. The maximum difference between mean values of the calculated HDX distributions for ions of the same charge in both cases does not exceed a few percent. In addition, HDX mass spectra of the apamin complex with an adduct of unknown structure were processed. Such analysis gave also three main fractions of ions with relatively large contributions when ND3 was injected into a radio-frequency quadrupole. In the absence of ND3 flow, the results of calculations for apamin and its complex were close to each other too. The formation of the apamin complex most probably in solution was confirmed by performed calculations.
Background and Aim: Phytobiotics are a safe alternative to feed antibiotics in industrial poultry farming that increases productivity by stimulating various digestive enzymes to reduce the number of pathogenic microorganisms in the intestines and improve antioxidant status and immune response. This study aimed to evaluate the effect of vanillic acid in its pure form and in combination with gamma lactone on weight growth and the physiological parameters of broiler chickens. Materials and Methods: The studies were performed on 120 Arbor Acres broiler chickens (7 days old) that were randomly divided into four groups with five replicates (cages) and six birds per replicate. The control group was fed the basal diet (BD) only. Group I was fed the BD + gamma lactone (average dose 0.07 mL/animal/day). Group II was fed the BD + vanillic acid (average dose 0.07 mL/animal/day). Group III was fed the BD + gamma lactone + vanillic acid in a 1:1 ratio (average dose 0.07 mL/body/day). Live weight of broiler chickens for all group was assessed at the end of each period (age of 7, 14, 21, 28, 35, 42 days). At the end of the experiment (on day 42), 10 broilers with an average live weight were selected for blood sampling from the axillary vein. Results: The results showed a growth-promoting effect of vanillic acid when fed with a diet free of synthetic antioxidants. Groups I and II had increased live weights throughout the entire experiment and a significant increase at the end of the experiment (8.2%–8.5%; p ≤ 0.05) compared to the control group. Toxic effects were not found in the biochemical blood serum analyses of Groups II and III. The metabolic processes in the experimental groups were intensified, especially in the enzyme associated with amino acid metabolism (gamma-glutamyl transferase) in Groups I and III (p ≤ 0.05). Vanillic acid, whether fed alone or in combination with gamma lactone, exhibited high antioxidant activities, protected cells from oxidative damage by inducing total antioxidant, catalase, and superoxide dismutase activities (p ≤ 0.05), and reduced the level of malondialdehyde (p ≤ 0.05) measured. No significant changes in the morphological blood parameters were found. Conclusion: The use of vanillic acid alone and in combination with gamma lactone increases the digestive enzyme activities in blood plasma, increases body weight, and has a positive effect on lipid metabolism and the antioxidant status of broiler chickens. These findings indicate the significant potential use of vanillic acid and gamma lactone in poultry due to their antioxidant properties. Keywords: antioxidant status, Arbor Acres cross, blood, broiler chickens, feeding, gamma lactone, productivity, vanillic acid.
In this article, we present the results of developing a model based on an RFR machine learning method using the ISIDA fragment descriptors for predicting the 11B NMR chemical shift of BODIPYs. The model is freely available at The model demonstrates the high quality of predicting the 11B NMR chemical shift (RMSE, 5CV (FINALE training set) = 0.40 ppm, RMSE (TEST set) = 0.14 ppm). In addition, we compared the "cost" and the user-friendliness for calculations using the quantum-chemical model with the DFT/GIAO approach. The 11B NMR chemical shift prediction accuracy (RMSE) of the model considered is more than three times higher and tremendously faster than the DFT/GIAO calculations. As a result, we provide a convenient tool and database that we collected for all researchers, that allows them to predict the 11B NMR chemical shift of boron-containing dyes. We believe that the new model will make it easier for researchers to correctly interpret the 11B NMR chemical shifts experimentally determined and to select more optimal conditions to perform an NMR experiment.
We present a multi-proxy reconstruction of the Holocene environment in the northern upper Kama region of Russia (59°52'-60°28'N, 54°28'-56°28'E) based upon the pollen, plant macrofossil and radiocarbon records of the sedimentary successions from the floodplain deposits of the river Kama. Palaeochannel and geochronological investigations allowed us to identify seven stages of floodplain development, which were formed through increases or decreases in the water flow of this actively meandering river during the Holocene. These changes in river flow and channel activity in the upper Kama valley most probably influenced the choice of ancient people for places to settle. Pollen records from the palaeochannel sediments reflect three phases of regional vegetation changes in the study area: (1) predominance of sparse taiga forests with Pinus (pine), Betula (birch), Picea obovata (Siberian spruce) and Larix (larch) in the early and beginning of the middle Holocene (9,800–6,400 cal bp); (2) expansion of P. obovata and penetration and spread of the temperate-climate broad-leaved trees Ulmus, Quercus, Tilia and Alnus in the middle Holocene (6,400–4,200 cal bp), and (3) appearance and spread of Abies sibirica (Siberian fir) between 4,200 and 3,400 cal bp, and formation of closed canopy Abies-Picea forest without broad-leaved trees from ca. 2,700 cal bp. Plant macrofossil assemblages from these palaeochannel sediments indicate local vegetation of wetland or semi-aquatic plant communities in this area. Our results showed that the increase in Betula and decrease of the conifers Picea, Pinus and Abies with synchronous increases of ruderal plants such as Chenopodiaceae and Artemisia and also grassland taxa show woodland clearance by humans in the Chalcolithic ca. 4,000 cal bp and in the early Iron Age and Middle Ages between 2,700 and 1,300 cal bp.
In this paper, we discuss a generalization of Vieta theorem (Vieta's formulas) to the case of Clifford geometric algebras. We compare the generalized Vieta formulas with the ordinary Vieta formulas for characteristic polynomial containing eigenvalues. We discuss Gelfand–Retakh noncommutative Vieta theorem and use it for the case of geometric algebras of small dimensions. We introduce the notion of a simple basis‐free formula for a determinant in geometric algebra and prove that a formula of this type exists in the case of arbitrary dimension. Using this notion, we present and prove generalized Vieta theorem in geometric algebra of arbitrary dimension. The results can be used in symbolic computation and various applications of geometric algebras in computer science, computer graphics, computer vision, physics, and engineering.
The phase‐field model for the description of the solidification processes with the glass‐crystal competition is suggested. The model combines the first‐order phase transition model in the phase‐field formalism and gauge‐field theory of glass transition. We present a self‐consistent system of stochastic motion equations for unconserved order parameters describing the crystal‐like short‐range ordering and vitrification. It is shown that the model qualitatively describes the glass‐crystal competition during quenching with finite cooling speed. The nucleation of the crystalline phase at slow cooling speeds and low undercoolings proceeds by a fluctuation mechanism. The model demonstrates the tendency to amorphization with the increase of its cooling rate.
Hypoxia-inducible factor 1 (HIF-1) is an oxygen-sensing transcriptional regulator orchestrating a complex of adaptive cellular responses to hypoxia. Several studies have demonstrated that toxic metal exposure may also modulate HIF-1α signal transduction pathway, although the existing data are scarce. Therefore, the present review aims to summarize the existing data on the effects of toxic metals on HIF-1 signaling and the potential underlying mechanisms with a special focus on prooxidant effect of the metals. The particular effect of metals was shown to be dependent on cell type, varying from down- to up-regulation of HIF-1 pathway. Inhibition of HIF-1 signaling may contribute to impaired hypoxic tolerance and adaptation, thus promoting hypoxic damage in the cells. In contrast, its metal-induced activation may result in increased tolerance to hypoxia through increased angiogenesis, thus promoting tumor growth and contributing to carcinogenic effect of heavy metals. Up-regulation of HIF-1 signaling is mainly observed upon Cr, As, and Ni exposure, whereas Cd and Hg may both stimulate and inhibit HIF-1 pathway. The mechanisms underlying the influence of toxic metal exposure on HIF-1 signaling involve modulation of prolyl hydroxylases (PHD2) activity, as well as interference with other tightly related pathways including Nrf2, PI3K/Akt, NF-κB, and MAPK signaling. These effects are at least partially mediated by metal-induced ROS generation. Hypothetically, maintenance of adequate HIF-1 signaling upon toxic metal exposure through direct (PHD2 modulation) or indirect (antioxidant) mechanisms may provide an additional strategy for prevention of adverse effects of metal toxicity.
This paper presents the results of mechanical tests by nanoindentation method of nanocomposite Al2O3 ceramics with 0.5 wt.% graphene obtained by plasma spark sintering. The following mechanical properties were studied depending on indentation depth: micro- and nanohardness, Young's modulus. Special attention was paid to fracture toughness. It is shown that the addition of carbon in the form of graphene can improve some of the properties of nanocomposite ceramics.
New anisotropic silicone magnetoactive composites were synthesized and studied. The surface structure and filler microdimensions in these elastomers were determined by electron microscopy. The atomic force microscopy use made it possible to determine significant surface deformations and magnetostrictive effects when small external magnetic fields are applied to the composites. Mössbauer spectroscopy on iron isotope nuclei made it possible to identify the fillers hyperfine parameters.
The paper presents the results of laser hardening of steels with a defocused and oscillating beam. The influence of changes in the scanning frequency, amplitude and defocusing of the laser beam on the parameters of laser quenching zones is considered. The objectives of this work were to determine the influence of the frequency of transverse vibrations, amplitude, defocusing, and the speed of movement of the laser beam for possible use in laser hardening and alloying of steels. At the first stage, single tracks with transverse fluctuations relative to the processing speed and with the scanning device turned off were applied to the surface of the samples in the center for half the length of the sample. To make the cuts, 10 mm were cut from both ends of the samples and polishing was performed according to the standard procedure. The determination of the geometric dimensions of the laser beam exposure zones was determined using a digital microscope. It is shown that the cross-sectional area of the hardened zones when using transverse beam vibrations is higher than when processing with a defocused beam, which leads to an increase in productivity during laser processing. Increasing the frequency of transverse vibrations of the beam makes it possible to obtain large volumes of molten bath on the surface, which can be used for alloying the friction surfaces of parts operating in severe operating conditions. The results obtained on laser hardening of steel with a zone width of up to 10 mm at a radiation power of 1000 W allow us to expand the technological possibilities of using laser processing. The microhardness of laser-hardened zones is 3 times higher than improved steel. The results of tribotechnical tests are presented showing an increase in the wear resistance and tear resistance of laser-hardened samples compared to steel.
This work is devoted to the study of the using the potential drop method possibility to identify local stress concentration zones and assess the metal deformation degree in these zones. Paper presents the finite element modeling results of the current circuits propagation in objects with locally deformed regions that occur in places of increased mechanical stresses concentrations. To identify areas with varying degrees of deformation, a method for recording the specific electrical conductivity increment is proposed (Δρ/ρ0) according to the voltages values δU detected as application result of the potential drop non-destructive method using a sinusoidal current source. The current circuits excitation at frequencies f less than 10000 Hz allowed us to determine the most informative approximating function δU(f) parameters, allowing to synthesize a model of multiple linear regression correlating with the parameter Δρ/ρ0 values, and with the degree of product material deformation.
The paper analyzes the relationship between the parameters of deformation facets formed as a result of the passage of a localized shear band or slip band through the initial medium- or high-angle grain boundary during plastic deformation of polycrystalline materials. Two models of facet formation are proposed: a discrete model in which the deformation in the band occur by the movement of lattice dislocations in parallel slip planes and a model in which the deformation is considered as the movement of continually and uniformly distributed virtual dislocations in the band. The dependences of the strength of mesodefects forming on deformation facets as a result of the passage of shear bands on the crystallographic and geometric parameters of the model are obtained.
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12,038 members
Vitaly I Korchagin
  • Institute of Gene Biology
Tatiana Artemevna Blyakharchuk
  • Institute of Monitoring of Climatic and Ecological Systems of the Siberian Branch
Leninsky Prospect, 14, 119991, Moscow, Moscow, Russia
Head of institution
Alexander M. Sergeev, President
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