bluuebunny/crossref_metadata_2025 huggingface dataset:
METHOD FOR TRAINING ELECTRICAL SELF-STIMULATION IN RESPONSE TO HEAD ELEVATION IN RATS BY A TELEMETRY SYSTEM THAT REGISTERS EXTRACELLULAR DOPAMINE LEVELS
Authors: Sizov V. V. , Lebedev A. A. , Pyurveev S. S. , Bychkov E. R. , Mukhin V. N. , Drobenkov A. V. , Shabanov P. D.
Published: April 2024

In this work, we propose a method for training rats electrical self-stimulation in response to rearing head in a telemetric system that records the level of extracellular dopamine. Initially, in the experiments of J. Olds, it was shown that in response to electrical stimulation of zones of positive reinforcement, rats exhibit natural exploratory behavior aimed at finding the source of the reward. It has been suggested that a natural behavioral act, in particular rearing head, can accelerate the development and stabilization of the self-stimulation reaction. A change in the position of the head can serve as an internal proprioceptive conditioned signal. The experiments were carried out in an annular chamber, where the ventral tegmental area (VTA) was stimulated using a telemetric system when the rat’s head was raised by 38°. The self-stimulation response to rearing head was developed and stabilized during the first day of training. With pedal self-stimulation, distinct repetitive reactions were observed only on the 3rd day of training after the procedures of “pushing” on the pedal on the 1st day of training and “repulsing” from the pedal on the 2nd day of training, stabilization of the reaction was observed only by the 4th day training. After stabilization of the self-stimulation response in rats, the level of extracellular dopamine in the nucleus accumbens was recorded by fast-scan cyclic voltammetry in response to the imposed stimulation of the VTA before and after each of the three series of self-stimulation lasting 10 minutes. After each series of self-stimulation, the level of extracellular dopamine decreased, which reflects the depletion of the intracellular pool of the neurotransmitter during prolonged self-stimulation of the VTA. The conclusion is made about the prospects of using the method of training rats to electrical self-stimulation in response to rearing head to study the mechanisms of reinforcement.
DYNAMICS OF THE EEG SENSORIMOTOR RHYTHM DURING MENTAL REPETITION OF THE OBSERVED MOVEMENT
Authors: Vasilyev A. N. , Makovskaya A. E. , Kaplan A. Ya.
Published: April 2024

Mental simulation of one’s own movement, or imagery of movement, as well as observation of other people’s movements are used in neurorehabilitation as methods of stimulation of sensorimotor parts of the brain. The present work tests a new way of representation - mental simulation of movement, synchronous with the movement observed from the first person on a video screen. The objectives of the study were to compare the reactivity of sensorimotor EEG rhythms during voluntary movement representation and representation following a video stimulus, and to identify the relationship between the phases of movement in the video and the dynamics of EEG patterns. The study involved 30 healthy volunteers in whom a 69-channel encephalogram was recorded during their performance and presentation of right thumb movements in two modes: arbitrarily (without an external reference) and synchronously imitating movement on a video clip. During EEG analysis, individual spatial-frequency components with the highest EEG mu-rhythm reactivity (8–14 Hz) were identified in the subjects, followed by quantitative assessment of desynchronization under the studied conditions based on analysis of probability density distributions of mu-rhythm power. A generalized additive model describing the function of responses to single events in the observed movements and their summation during serial execution or presentation of the movements was applied to assess the relationship between the dynamics of mu-rhythm desynchronization and video events. It was shown that the mental kinesthetic simulation of the observed movement did not result in increased desynchronization of sensorimotor rhythms compared to the voluntary representation of the same movement. It was found for the first time that there are perturbations in the temporal course of desynchronization of the mu-rhythm that depend on the phase and speed of the observed movement both during its synchronous muscle repetition and during mental synchronous imitation. The results obtained can be used to optimize movement parameters in individual systems of ideomotor training with EEG control to achieve the greatest sensorimotor activation.
ON OPTIMIZING MINISCOPE DATA ANALYSIS WITH SIMULATED DATA: A STUDY OF PARAMETER OPTIMIZATION IN THE MINIAN ANALYSIS PIPELINE
Authors: Erofeev A. I. , Petrushan M. V. , Lysenko L. V. , Vinokurov E. K. , Vlasova O. L. , Bezprozvanny I. B.
Published: April 2024

In vivo calcium imaging is widely used technique in neuroscience to evaluate the activity of neuronal networks. The miniscope, a single-photon miniature fluorescent microscope, has made it possible to conduct in vivo calcium imaging in freely moving animals. Various algorithms and software packages have been developed for the analysis of miniscope data. This study investigates the relationship between the sensitivity of neuron detection and the processing parameters utilized in the Minian analysis pipeline at different noise levels. To achieve this objective, we generated simulated data possessing certain attributes of an experimentally derived dataset. Simulated data was generated with various noise levels and processed through to the Minian analysis pipeline. Based on our findings, we provide recommendations for optimal values of Minian pipeline parameters depending on different noise levels. The results obtained in this study may serve as a preliminary guide for selecting appropriate parameter values during the processing of experimental data using the Minian analysis pipeline. The findings of this study are expected to be relevant to neuroscientists involved in the acquisition and processing of miniscope data.
Equivalence of Entropy and Renormalized Solutions of a Nonlinear Elliptic Problem in Musielak–Orlicz Spaces
Authors: Kozhevnikova L. M , Kashnikova A. P
Published: April 2024

We consider second-order elliptic equations with nonlinearities determined by Musielak–Orlicz functions and with right-hand side in the space. In the Musielak–Orlicz–Sobolev spaces, we establish some properties and uniqueness of both entropy and renormalized solutions of the Dirichlet problem in domains with Lipschitz boundary. In addition, the equivalence and sign-definiteness of the entropy and renormalized solutions is proved.
Solution Blow-Up and Global Solvability of the Cauchy Problem for a Model Third-Order Partial Differential Equation
Authors: Umarov Kh. G
Published: April 2024

We obtain conditions for the existence of a global solution and the blow-up of the solution of the Cauchy problem on a finite time interval for a nonlinear third-order partial differential equation generalizing the equation of torsion vibrations of a cylindrical rod with allowance for internal and external damping modeling the propagation of longitudinal stress waves along a one-dimensional viscoelastic rod whose the material obeys Voigt–Kelvin medium deformation law.
A Continuous Method for Finding a Generalized Fixed Point of a Nonexpansive Mapping on a Set in a Hilbert Space
Authors: Ryazantseva I. P
Published: April 2024

We introduce the concept of a generalized fixed point of a nonexpansive operator on a convex closed set in a Hilbert space. To find this point, we construct a regularizing algorithm in the form of the Cauchy problem for a first-order differential equation and establish sufficient conditions for the strong convergence of the resulting approximations to a normal generalized fixed point under approximate specification of the nonexpansive operator and the convex closed set on which the desired generalized fixed point of the operator is located. Examples of parametric functions are given that ensure the convergence of the approximations in the norm of the Hilbert space to a normal generalized fixed point of the operator on the convex closed set in this space.
Spectral Properties of the Generator of a Semigroup Generated by the Volterra Integro-Differential Equation
Authors: Vlasov V. V , Rautian N. A
Published: April 2024

The spectral properties of a linear operator that is the generator of a semigroup generated by a Volterra integro-differential equation in a Hilbert space are studied. Such integro-differential equations can be implemented as partial integro-differential equations arising in the theory of viscoelasticity and the theory of heat propagation in media with memory and also have many other important applications.The established results on the Riesz basis property of the root vectors of the semigroup generator can be used in studying the properties of solutions of integro-differential equations.
A Special Version of the Collocation Method for One Class of Integro-Differential Equations
Authors: Gabbasov N. S
Published: April 2024

A linear integro-differential equation with a singular differential operator in the main part is studied. To find its approximate solution in the space of generalized functions, a special version of the generalized collocation method is proposed and justified
Stabilization of a Differential-Difference System of Delay Type
Authors: Metel'skiy A. V
Published: April 2024

For a linear autonomous differential-difference system with commensurate delays, algorithms for constructing controllers that provide asymptotic, finite-time, or complete stabilization of this system are substantiated. A distinctive feature of the proposed approach is that it does not require a priori information about the location of the roots of the characteristic quasipolynomial of the original system. The results are illustrated with examples.
Traveling Wave Method
Authors: Borovskikh A. V
Published: April 2024

A survey of the development of the traveling wave method for one-dimensional media is presented. The main results and changes in the statement of the problem of representing solutions of linear systems of partial differential equations in terms of “traveling waves” (more precisely, in terms of a system of wave transport equations) are presented. It is shown that as the study of systems becomes more complicated, the problem of representing the solution by the traveling wave method turns out to be applicable not only for hyperbolic systems but also for systems containing (even implicitly) both parabolic and elliptic components and thereby approaches the general problem of decomposition of an arbitrary system of linear equations into a system of first-order equations with a main part of the canonical type and with a subordinate linear part.
O gipersingulyarnykh operatorakh, svyazannykh s peridinamikoy
Authors: Alimov Sh. A , Sheraliev Sh. N
Published: April 2024

For a hypersingular integral operator of the Calderón–Zygmund type associated with problems of peridynamics, we find a Hilbert space that is taken by this operator to the space of square integrable periodic functions.
On the Fredholm Property and Solvability of a System of Integral Equations in the Transmission Problem for the Helmholtz Equation
Authors: Smirnov Yu. G , Kondyrev O. V
Published: April 2024

A scalar three-dimensional boundary value problem of wave diffraction for the Helmholtz equation with transmission conditions that assume the presence of an infinitely thin material at the media interface is considered. Uniqueness and existence theorems for solutions are proved. The original problem is reduced to a system of integral equations over the media interface. Calculation formulas for the system of linear algebraic equations obtained after applying the collocation method and numerical results for solving the problem when the domain is a ball with certain transmission conditions are given.
On a Control Problem for a System of Implicit Differential Equations
Authors: Zhukovskiy E. S. , Serova I. D.
Published: April 2024

We consider the differential inclusion F(t,x,x˙)∋0 with the constraint x˙(t)∈B(t), t∈[a,b], on the derivative of the unknown function, where F and B are set-valued mappings, F:[a,b]×Rn×Rn×Rm⇉ is superpositionally measurable, and B:[a,b]⇉Rn is measurable. In terms of the properties of ordered covering and the monotonicity of set-valued mappings acting in finite-dimensional spaces, for the Cauchy problem we obtain conditions for the existence and estimates of solutions as well as conditions for the existence of a solution with the smallest derivative. Based on these results, we study a control system of the form f(t,x,x˙,u)=0, x˙(t)∈B(t), u(t)∈U(t,x,x˙), t∈[a,b].
On a Positional Control Problem for a Nonlinear Equation with Distributed Parameters
Authors: Maksimov V. I.
Published: April 2024

We consider a guaranteed control problem for a nonlinear distributed equation of diffusion type. The problem is essentially to construct a feedback control algorithm ensuring that the solution of a given equation tracks the solution of a similar equation subjected to an unknown disturbance. The case in which a discontinuous unbounded function can be a feasible disturbance is studied. We solve the problem under conditions of inaccurate measurement of solutions of each of the equations at discrete instants of time and indicate a solution algorithm robust under information noise and calculation errors.
On the Stability of Periodic Solutions of a Model Navier–Stokes Equation in a Thin Layer
Authors: Boldyreva E. S.
Published: April 2024

We study the existence and stability of periodic solutions of the model Navier–Stokes equation in a thin three-dimensional layer depending on the existence and stability of periodic solutions of a special limit two-dimensional equation.
Hopf Bifurcation in a Predator–Prey System with Infection
Authors: Krishchenko A. P. , Podderegin O. A.
Published: April 2024

We study a model of a predator–prey system with possible infection of prey in the form of a three-dimensional system of ordinary differential equations. Using the localization method of compact invariant sets, the existence of an attractor is proved and a compact positively invariant set is found that estimates its position. The conditions for the extinction of populations and the existence of equilibria are found. A numerical method for finding a Hopf bifurcation of the inner equilibrium is proposed and an example of an arising stable limit cycle is given.
New applications of ninhydrin in the synthesis of polyheterocyclic compounds
Authors: Velikorodov A. V , Zukhairaeva A. S , Kutlalieva E. N , Shustova E. A , Nosachev S. B
Published: April 2024

The review demonstrates new areas of application of ninhydrin as a universal reagent in organic synthesis for the construction of a wide range of polycyclic compounds with benzofuran, pyrroline, pyrrole, imidazole, pyrimidine, propellanic and other fragments.
Synthesis and some transformations of new acetophenones with carbamate function
Authors: Velikorodov A. V , Kutlalieva E. N , Nosachev S. B , Shustova E. A
Published: April 2024

Acylation of methyl- N -phenyl-, 2-(morpholin-4-yl)ethylphenyl-, 2-(pyridin-2-yl)ethylphenyl-carbamates with acetic anhydride in polyphosphoric acid at 50-55°C for 3 h proceeds in the para -position to the carbamate grouping to form the corresponding acetophenones. Acylation under similar conditions of methyl 2-(methoxyphenyl)carbamate occurs in the para -position to the methoxy group with the formation of methyl N -(5-acetyl-2-methoxyphenyl)carbamate. The interaction of para - and ortho -acetyl-substituted methyl- N -phenylcarbamate with N -bromosuccinimide, copper(II) acetate in the presence of dimethylformamide at 80°C and with chloro- and hydrobromic acids in the presence of DMSO in ethyl acetate at 30-33°C yielded methyl {4(2)-[(dimethylamino)(oxo)-acetyl]phenyl}- and N -[4(2)-(2-bromo-2-chloroacetyl)phenyl]-carbamates. Condensation of 2-morpholinoethyl [(pyridin-2-yl)ethyl] N -(4-acetylphenyl)carbamates with 4-methoxybenzaldehyde in the presence of a methanolic KOH solution gave the corresponding chalcones.
Synthesis and aminomethylation of A-azepanederivatives of uvaol and betulin
Authors: Petrova A. V
Published: April 2024

By stepwise conjugation of biologically active A-azepanobetulin or A-azepanouvaol with succinic anhydride and propargylamine, followed by a Cu-catalyzed Mannich reaction, new hybrid derivatives with an N -methylpiperazine fragment were synthesized with an average yield of 73%. The structure of the obtained compounds was established using NMR spectroscopy.
Synthesis of C60 fullerene hybrid molecules with catecholamines under the action of ultrasound
Authors: Kinzyabaeva Z. S , Sabirov D. Sh.
Published: April 2024

For the first time, morpholine monoadducts of С60-fullerene were obtained in the reactions of fullerene with biogenic amines (norepinephrine, adrenaline) under the action of ultrasound. The reactions take place in air in ( g 2.0000 and Δ H 1/2 3.2 G) was detected by EPR, a key intermediate in the synthesis of the C60-adrenaline cycloadduct, which was obtained as a result •-a toluene/DMF medium at room temperature. The radical anion C60- of a one-electron transition from the adrenaline molecule to the C60 framework.
Synthesis, chemocal properties and application of 2-substituted derivatives of thiazolo[3,2-a]pyrimidine
Authors: Agarkov A. S , Shiryaev A. K , Solovieva S. E , Antipin I. S
Published: April 2024

The review describes in detail the methods of obtaining thiazolo[3,2- a ]pyrimidines, synthesis and chemical properties of 2-substituted derivatives of thiazolo[3,2- a ]pyrimidines, analysis of crystal structures of 2-arylmethylidene derivatives of thiazolo[3,2- a ]pyrimidines and demonstrates their high antitumor, antibacterial and anti-inflammatory activity.
Catalyst-free reactions of Schiff bases with cyanopropargyl alcohols: synthesis of functionalized 1,3-oxazolidines
Authors: Oparina L. A , Grishchenko L. A , Kolyvanov N. A , Ushakov I. A , Trofimov B. A
Published: April 2024

Schiff bases react with cyanopropargylic alcohols (80°C, 10-12 h) in the absence of catalysts and solvents to afford functionalized 1,3-oxazolidines in up to 82% yield. The reaction proceeds through a cascade of transformations including the formation of a 1,3-dipolar intermediate via the addition of a neutral N -nucleophile to the activated triple bond, the proton transfer from the hydroxyl group to the carbanionic center of the intermediate, and the intramolecular attack of the carbonyl carbon of the Schiff base by the O -centered anion to close 1,3-oxazolidine cycle.
Heterocycles on the base of bis(trifluoromethyl)imidazolidin-2-ones, 2-aminoethanol and 2-aminophenol
Authors: Saloutina L. V , Kodess M. I , Ganebnykh I. N , Slepukhin P. A , Saloutin V. I , Chupakhin O. N
Published: April 2024

Novel trifluoromethyl-containing imidazo-1,4-oxazines have been synthesized through the condensation reaction of 4,5-dihydroxy-4,5-bis(trifluoromethyl)imidazolidin-2-one with 2-aminoethanol (2-AE) and 2-aminophenol (2-APh). Unusual route of the reaction of 1-methyl(phenyl)- 4,5-dihydroxy-4,5-bis(trifluoromethyl)imidazolidin-2-ones with 2-AE has been found, leading to hydroxyethylamino-substituted hydantoins. The interaction of the N-substituted imidazolidines with 2-APh under similar conditions led to formation of rearrangement products, 5,5-bis(trifluoromethyl)hydantoins. The molecular structure of 5-[(2-hydroxyethyl)amino]-3-methyl-5-(trifluoromethyl)imidazolidin-2,4-dione has been studied by X-ray diffraction experiment.
Decyclization of substituted 3-(4-nitrobenzoyl)hydrasono3H-furan-2-ones under the action of primary alcohols and investigation of analgesic activity and acute toxicity of reaction products
Authors: Lipin D. V , Denisova E. I , Shipilovskikh D. A , Makhmudov R. R , Igidov N. M , Shipilovskikh S. A
Published: April 2024

The decyclization of substituted 3-(4-nitrobenzoyl)hydrazono-3 H -furan-2-ones under the action of primary alcohols, which proceeds with the formation of the corresponding substituted 2-[2-(4-nitrobenzoyl)hydrazono]-4-oxobutanoates, has been studied. The analgesic activity and acute toxicity of the obtained compounds were studied, it was found that the obtained compounds exhibit a pronounced analgesic effect, and also have low toxicity. According to the drug toxicity classification, the obtained primary substituted 2-[2-(4-nitrobenzoyl)hydrazono]-4-oxobutanoates belong to class V of practically non-toxic drugs.
Conversions of seven-membered terpene lactones towards low-molecular bioregulators
Authors: Vydrina V. A , Yakovleva M. P , Ishmuratov G. Yu.
Published: April 2024

The review describes the low-temperature reduction of (-)-mentholactone with diisobutylaluminum hydride in methylene chloride studied by the authors. It was found that, depending on the reaction conditions, it proceeds with the formation of three products: 7 S -isopropyl-4 R -methyloxepan-2 S -ol [(-)-mentholactol], 8-hydroxy-2,6 R -dimethyloctan-3-one or 2 S -isobutoxy-7 S -isopropyl-4 R -methyloxepane, for each of which the probable routes are given and the conditions for selective formation are selected. A new reaction in the chemistry of organoaluminum compounds has been discovered - the formation of isobutyl acetals of 2-oxepanols during low-temperature (-70°C) reduction of 7-membered lactones with two-fold or more molar amounts of diisobutylaluminum hydride in methylene chloride. On the basis of (-)-mentholactol, its aluminate, and 8-hydroxy-2,6R-dimethyloctan-3-one, a number of low molecular weight bioregulators, including optically active pheromones of insect pests in agriculture and forestry, have been synthesized.
Synthesis and biological activity of 4-fluorophenylcyclohexyl(tetrahydropyranyl)methyl-substituted aryloxypropanolamines
Authors: Aghekyan A. A , Mkryan G. G , Melikyan G. S , Panosyan H. A , Tsatinyan A. S , Grigoryan A. S , Gasparyan H. V
Published: April 2024

By alkylation of 4-fluorophenylacetonitrile with dibrompеntane and 2.2-dichlor-diethylether the corresponding nitriles were obtained, with which reduction by lithium aluminium hydride [1-(4-fluorophenyl)cyclohexyl]- and [1-(4-fluorophenyl)tetrahydro-2 H -pyran-4-yl]methanamines were isolated. By the reaction of the latters with substituted in aromatic cycles aryloxymethyloxiranes new aryloxypropanolamines were been synthesized. Some of them by the action of formaline were transformed to the corresponding oxazolidines.
Pecularities of 16-nitro- and 16-amino-14,17-ethanosteroids preparation in the estrane series
Authors: Baranovsky A. V , Ladyko A. S , Sokolov S. N
Published: April 2024

The hydrogenation of 16-nitro-14,17-ethenosteroids over various catalysts was studied, chemoselectivity criteria have been established, new bridged estradiol analogs bearing nitro, amino and hydroxylamino groups in the D ring have been prepared. A complete assignment of signals in the NMR spectra of the synthesized products was fulfilled
Recycling of 4-(2,2,2-trichloroacetyl)furan-2,3-diones under the action of (hetero)arylhydrazides
Authors: Kharitonova S. S , Nasibullina E. R , Ivanov D. V , Lisovenko N. Yu.
Published: April 2024

The interaction of 4-(2,2,2-trichloroacetyl)furan-2,3-diones with aryl- or thienoyl hydrazides in anhydrous chloroform with stirring for several hours leads to the formation of a mixture of diasteriomers A and B (ratio approximately 70:30) of 1-substituted 3-aryl-4,5-dihydro-5-hydroxy-4-(2,2,2-trichloroacetyl)-1 H -pyrazole-5-carboxylic acids.
A facile and convenient synthesis of di(n-butyl)carbonate-(carbonyl-13C)
Authors: Trukhin D. V , Rogozhnikova O. Yu. , Salnikova O. I , Tormyshev V. M
Published: April 2024

Reaction of silver-13C carbonate, obtained from readily available barium-13C carbonate, with 1-iodobutane resulted in formation of di( n -butyl)carbonate-( carbonyl -13C) isolated in high yield via simple and convenient laboratory procedure.
Enantioselective aminomethylation of 1-(benzyloxy)propan-2-one with an aromatic C-ethyl substituted propargyl amine ether
Authors: Talybov G. M
Published: April 2024

Enantioselective aminomethylation of 1-(benzyloxy)propan-2-one with an aromatic propargyl amino ether in the presence of a chiral pseudoephedrine catalyst in an aqueous medium gave anti / syn products with high yields and optical purity.
Multicomponent synthesis of cycloalca[b]pyridines and pyrans
Authors: Dyachenko I. V , Dyachenko V. D , Dorovatovskii P. V , Khrustalev V. N , Nenajdenko V. G
Published: April 2024

New condensed pyridines and pyrans were synthesized using multicomponent condensation. A number of compounds was studied by X-ray structural analysis.
Transformations of 2-(1-chloroethenyl)naphthalene in the presence of pd(0) nanoparticles on a glass substrate
Authors: Mohammed M. S , Kovalev I. S , Volkova N. N , Zyryanov G. V , Ranu B. C , Chupakhin O. N
Published: April 2024

Homo-and cross-coupling products were obtained in an attempt to obtain 2-ethynylnaphthalene from 2-(1-chloroethenyl)maphthalene in a glass reactor contaminated with palladium black nanoparticles on the inner wall. The structure of reaction products was characterized by the GC-MS method.
Application of CO2 as С1-Synthon in Organic Chemistry: II: Catalytic Synthesis of Cyclic Carbonates (Carbamates) from CO2 and Epoxides (Aziridines)
Authors: Kuznetsov N. Yu. , Beletskaya I. P.
Published: April 2024

CO2 composes cheap, easily available and practically inexhaustible source of synthetic carbon (C1-synthon). Among the various transformations of carbon dioxide, synthesis of cyclic carbonates from epoxides and carbamates from aziridines can be referred to the priority areas in the development of contemporary chemical synthesis and catalysis. Cyclic carbonates found wide application in modern industry (electrolytes, solvents, reagents, polymers) and their use and production will be constantly increased. At the forefront of research appears the development of effective catalytic processes, allowing carry out the synthesis of carbonates under mild conditions (atmospheric pressure of CO2 or lower, temperature - 25°С) with low catalyst loads, which sustains its high activity for a long time and is affordable. In the current review we analyze the existing directions of research and catalytic systems based on salts of cheap and earth-abundant metals Al3+, Fe2+(3+) and Zn2+ for the preparation of cyclic carbonates from epoxides and carbamates from aziridines.
Dynamic Structure of Organic Compounds in Solution According to NMR Data and Quantum Mechanical Calculations: IV. Benzamide
Authors: Stanishevskiy V. V. , Schestakova A. K. , Chertkov V. A.
Published: April 2024

To study the structure and dynamics of nitrogen-containing compounds, NMR parameters with directly involved nitrogen can provide valuable structure information. However, this information can only be obtained using15N-enriched compounds due to low natural abundance of 15N and extremely short relaxation of 14N nuclei. For synthesis of these compounds from 15N-ammonium salts, 15N-enriched benzamides often used as intermediates. In the present work, we study the dynamic structure of benzamide caused by two independent factors: hindered internal rotation of the NH2 group around the C(O)-N bond and the amide group as a whole relative to the benzene ring. This deeper knowledge of mechanism and parameters of these processes in amides is important for meaningful interpretation and prediction of the biological activity of aromatic amides in living systems, the strength and conformation of its supramolecular complexes with lanthanide and actinide ions. Double enriched [2H5, 15N]benzamide was synthesized to avoid unwanted superposition of intense aromatic multiplet on the amide signals in the 1H NMR spectra. In the 1H spectrum of this compound observed only intense signals of amide protons, which allowed accurate quantitative characterization of the parameters of the dynamic processes under study. The experimental data obtained is in good agreement with our results of simulation by quantum molecular dynamics techniques.
Synthesis, crystal structure and biological activity of hydroxyphosphonates
Authors: Sedov A. N. , Davletshin R. R. , Davletshina N. V. , Ivshin K. A. , Fedonin A. P. , Osogostok A. R. , Shulaeva M. P.
Published: April 2024

A series of О,О-dialkyl((aryl(hydroxy)methyl)phosphonates 1-4 with various substituents at the phosphorus atom was obtained by the Abramov reaction. The structure of the isolated products was confirmed by a complex of physical research methods: NMR, IR spectroscopy, mass spectrometry, and X-ray diffraction analysis. All the obtained compounds demonstrated activity against strains of B. cereus and S. aureus bacteria.
NBS-induced triflamidation of 2-methyl-1-pentene
Authors: Astakhova V. V. , Moskalik M. Yu.
Published: April 2024

Reaction of trifluoromethanesulfonamide with 2-methyl-1-pentene in the presence of N -bromosuccinimide in acetonitrile leads to N -{2-methyl-1-[(trifluoromethyl)sulfonamido]pentan-2-yl}acetamide. Cyclization of N -[1-phenyl-2-(triflamido)ethyl]acetamide with excess K2CO3 gives the corresponding 4,5-dihydro-1 H imidazole.
Synthesis and antibacterial activity of the cyclic 2-substituted thyenopyrimidin-4-ones by bubbling with hydrochloric gas of cycloalkane[b]-2-(n-acylamino)-3-cyanothiophenes
Authors: Isakhanyan A. U. , Hakobyan N. Z. , Panosyan G. A. , Harutyunyan A. A.
Published: April 2024

The reaction of acylation of some 2-amino-3-cyanocycloalkane[ b ]thiophenes with chlorides of various carboxylic acids gave the corresponding cycloalkane[ b ]-2-( N -acylamino)-3-cyanothiophenes, bubbling with hydrochloric gas from an alcoholic solution of amidonitriles to obtain cyclic 2-substituted thienopyrimidin-4-ones. The study of the antibacterial activity of the compounds against gram-positive and gram-negative microorganisms showed that most of them exhibit a weak antibacterial effect against staphylococci.
New macrocyclic bis-1,10-phenanthroline-2,9-diamides. synthesis and stereodynamics in solutions
Authors: Ustynyuk Yu. A. , Petrov V. S , Lemport P. S , Roznyatovsky V. A , Nenajdenko V. G
Published: April 2024

New examples of macrocyclic 1,10-phenanthroline-2,9-diamides containing simultaneously two phenanthroline moiety in their structure have been obtained. The structure of the obtained compounds was confirmed by NMR spectroscopy and other methods. New macrocyclic phenanthrolines expectedly exhibit complex stereodynamic behavior in solutions. This effect was studied using 1H NMR spectroscopy at various temperatures.
Application of the Knorr reaction for the directional synthesis of pyrazole derivative as a biologically active co-ligandes of gold glyco-nanoparticles
Authors: Ershov A. Y. , Martynenkov A. A. , Lagoda I. V. , Batyrenko A. A.
Published: April 2024

Based on the reaction of acetylacetone with 6-mercaptohexanoic and 11-mercaptoundecanoic acid hydrazides, a method was developed for the synthesis of previously unknown 1-(ω-mercaptoacyl)-3,5-dimethylpyrazole as promising сo-ligand for the preparation of gold glyco-nanoparticles for biomedical purposes.
Available method for the synthesis of E-N-substituted-2-diphenylphosphorylaziridines
Authors: Bichakhchyan A. S. , Derdzyan L. V. , Poghosyan A. S. , Panosyan H. A. , Arakelyan A. G. , Stepanyan H. M. , Muradyan R. E. , Gasparyan G. Ts.
Published: April 2024

An available method for the synthesis of 2-diphenylphosphoryl- N -substituted aziridines with high yields has been developed by the interaction of (1,2-dibromoethyl)(diphenyl)phosphine oxide with a number of primary amines, in particular, methyl-, ethyl-, isopropyl-, tert -butyl-, cyclohexyl- and benzylamines at room temperature in the presence of sodium hydroxide. The antibacterial activity of obtained compounds was studied.
Second All-Russian school of medical chemistry for young scientists
Authors: Bakulina O. Yu. , Sapegin A. V. , Yarovaya O. I.
Published: April 2024

The second school in medicinal chemistry was held from July 3 to July 6, 2023 at St. Petersburg State University as part of the All-Russian conference with international participation “Ideas and legacy of A.E. Favorsky in organic chemistry” with the support of the St. Petersburg branch of D.I. Mendeleev Russian Chemical Society. Leading experts in the field of medicinal chemistry, young scientists and students from various institutes and universities of Russia took part in the work.
GEOECOLOGICAL PROBLEMS UPON IMPROVEMENT OF HISTORIC CITIES AND PRESERVATION OF HISTORIC URBAN HERITAGE
Authors: Belyaeva E. L. , Kashperyuk P. I. , Moginov B. G. , Rezyapkin I. P.
Published: April 2024

In spite of the fact that almost everywhere in the territories of historic cities, under the influence of the shortcomings of landscaping, there is a progressive technogenesis of the geological environment and groundwater, which can lead to the destruction of architectural monuments and historically valuable buildings, this problem remains poorly studied. Given the enormous scale of work on the improvement of the historical territories, which is planned to perform under the national projects and municipal programs, the study of this direction to improve the design methodology and engineering surveys as an objective basis for the development of design decisions, is very relevant. For the historical territories of cities that include architectural monuments and valuable buildings, specialized methods of design and engineering and environmental surveys, geoecological monitoring, including measures to ensure the preservation of cultural heritage, are necessary. The article provides a review of literary sources, analysis of examples, and actual data confirming the impact of landscaping factors on the state of cultural heritage sites (CHS). The most significant in terms of the impact on the geological environment and, accordingly, on the preservation of monuments of architecture are the shortcomings of vertical planning and drainage. In the conditions of high-density housing development, the unsatisfactory improvement can stimulate the processes of underflooding, suffosion, and karst, as well as the general technogenesis of soils, and loss of the bearing capacity of the bases and foundations. Underflooding of basements, “soaking” of walls, and formation of cracks on facades can be observed in architectural monuments and historical buildings. The study summarizes the observations and results obtained by the authors – representatives of various specialties (engineers, geologist, architect-restorer) at various stages of their creative work and takes into account the long experience of OOO “IGBI” on the design of improvement on the historical territories of Moscow.
EVALUATION OF CLIMATE-INDUCED EVOLUTION OF THE MORPHOLOGICAL STRUCTURE OF THERMOKARST PLAINS IN THE PERMAFROST ZONE USING REMOTE SENSING DATA
Authors: Viktorov A. S. , Arkhipova M. V. , Kapralova V. N. , Orlov T. V. , Trapeznikova O. N.
Published: April 2024

Changing geocryological conditions and the permafrost zone landscape due to climate change is currently an acute issue actively studied by many researchers. However, insufficient attention is paid to the change in the morphological structure and quantitative analysis. The aim of the study was a quantitative analysis of morphological structure of the thermokarst plains with fluvial erosion and lacustrine thermokarst plains. The study was carried out based on satellite imagery, including archival images of Corona with a resolution of 3–12 m/pix, for 1961–1979, and a set of modern high-resolution images of 0.5–2.5 m/pix for 2008–2019. Analysis of changes in the morphological structure of thermokarst plains was carried out in 9 key areas located in the zone of continuous permafrost, in the north of the West Siberian Lowland, at the mouth of the Lena River, in Eastern Siberia, on Baffin Island. Checking statistical differences between samples 1961–1979 and 2013–2019 using the Smirnov criterion revealed statistically significant differences in the distributions of lake areas of the thermokarst plains with fluvial erosion in only two sites. In one of these areas, the changes are of a smooth and integral-exponential form of the distribution of lake areas preserved. Assessment of the significance of statistical differences for 1964–1976 and 2008–2014 for the thermokarst plains revealed a significant difference for only one area. The change in the morphological structure of the thermokarst plains with fluvial erosion due to climatic changes is more intense than that of thermokarst plains; changes affected 22% of key areas versus 12% near thermokarst plains with fluvial erosion. Key areas where changes have been identified are located on the Yamal Peninsula. The resistance of morphological structures to climatic changes is higher than that of individual components of the landscape. Erosion processes are the first to respond to climatic changes, and the change in these processes leads to a change in the distribution of the areas of thermokarst lakes in thermokarst plains with fluvial erosion during the intensification of their descent and transformation into khasyreys.
CHANGES IN GEODYNAMIC SITUATION MANIFESTED IN SOIL RADON AND TEMPERATURE VARIATIONS AND ABNORMAL NATURAL PHENOMENA IN THE ZONE OF KATAV-IVANOVSK EARTHQUAKE (05.09.2018), THE SOUTHERN URALS
Authors: Yurkov A. K. , Kozlova I. A. , Biryulin S. V. , Khatskevich B. D.
Published: April 2024

The strongest earthquake in the Urals registered during the period of instrumental observations, with a magnitude of ML-5.4 occurred in the area of Katav-Ivanovsk city, Chelyabinsk region, on 05.09.2018. In October 2018, Institute of Geophysics, the Ural Branch RAS organized temperature and radon observations. The conducted studies have shown that the behavior patterns of the volume radon activity (VRA) established for the tectonic event preparation in the subduction zone (Southern Kuriles), are also true for the South Ural region. The natural phenomena caused by the earthquake 2018 preparation are analyzed. During the observation period from 28.11.2018 to 23.05.2019, there was an increase in temperature with a gradient of 0.02°C per month. The observed patterns of VRA abnormal behavior before aftershocks in the Katav-Ivanovsk area are typical for the compression zone in the radon monitoring area. It is noted that the assumed compression deformations were manifested in the hydrogeodynamic field at least 10 years before the event proper. The proximity of earthquake foci to the identified aseismic zone within the boundaries of the East European Platform, the Pre-Ural Regional Trough, and the Bashkir anticlinorium indicates the most likely places of seismic events. The arranged temperature and radon monitoring network in the epicentral zone by observing aftershocks has shown the possibility of tracking the earthquake preparation process.
ANALYSIS OF THE EXOGENOUS GEOLOGICAL PROCESS DEVELOPMENT BASED ON THE MODELS OF THE MATHEMATICAL MORPHOLOGY OF LANDSCAPES
Authors: Viktorov A. S. , Kapralova V. N. , Orlov T. V.
Published: April 2024

The paper aims to show the efficiency of applying the approaches used in the mathematical morphology of landscapes to the analysis of exogenous geological process development. Taking thermokarst plains with fluvial erosion as an example, it is shown that the approaches of the mathematical morphology of landscapes permit analyzing the terrain development under complex conditions of several interacting exogenous geological processes. Thermokarst areas develop under the impact of two interacting processes, i.e., thermokarst and fluvial thermoerosion. They include the following stages: constant generation of new thermokarst foci, constant decrease in the number of the thermokarst foci, when lakes are drained by thermoerosion, constant change in the conditions for the development of new thermokarst foci due to the transformation of the main surface into the khasyrei surface. The approaches of the mathematical morphology of landscapes revealed that each of the two types of surface within the thermokarst plains with fluvial erosion reached a dynamic balance upon the emergence, growth, and drainage of thermokarst lakes. Taking the formation and development of thermal cirques on abrasion shores within the permafrost zone as an example, it is shown that the approaches of the mathematical morphology of landscapes make it possible to analyze a set of processes for thermal cirques development under complex interaction of their foci. Based on the analysis of the mathematical model of the formation and development of thermal cirques, it is shown that in conditions of an abrasion slope that is relatively homogeneous in terms of geological and geocryological conditions, a dynamic balance is reached. It is characterized by stabilizing two parameters: the average density of thermal cirques and the probabilistic distribution of the thermal cirque size along the slope strike. An analytical relationship was obtained between the probabilistic distributions of chord sizes of the forming young landslides and all presented landslides, including partly erased ones by the later landslides; and the relationship between the average statistical forms of landslides along the coastline and the distribution parameters of the chord sizes of the forming young landslides. The obtained regularities were tested at several sites based on remote sensing data.
A NEW TECHNOLOGY FOR RECOVERY OF LOCOMOTION IN PATIENTS AFTER A STROKE
Authors: Moshonkina T. R. , Zharova E. N. , Ananev S. S. , Shanybina N. D. , Vershinina E. A. , Lyakhovetskii V. A. , Grishin A. A. , Shlyakhto E. V. , Gerasimenko Y. P.
Published: April 2024

Neural networks in the spinal cord can generate the walking pattern and control posture in the absence of supraspinal influences. A technology has been created using transcutaneous electrical spinal cord stimulation (tSCS). During walking, tSCS activated spinal locomotor networks, as well as leg flexor/extensor motor pools in the swing/support phases, respectively. It was suggested that the use of this technology in people with locomotion disorders would improve walking. Patients with hemiparesis were studied 3–11 months after a stroke, the duration of the course was 2 weeks. Patients of the main and control groups received standard therapy and rehabilitation using technology; in the control group, sham tESCS was used. After the course in the main group, in contrast to the control group, minimal clinically significant changes in walking parameters were achieved. The developed technology is an effective means of restoring walking in patients with hemiparesis.
CHLOROPHYLL A DIMERS HARBORED BY WATER-SOLUBLE PROTEIN BoWSCP PHOTOSENSITIZE REDUCTION OF CYTOCHROME C
Authors: Obukhov Yu. N. , Neverov K. V. , Maleeva Yu. V. , Kritsky M. S.
Published: April 2024

When bound to water-soluble proteins of the WSCP family, chlorophyll molecules form dimers structurally similar to “special pair” of chlorophylls (bacteriochlorophylls) in photosynthetic reaction centers. Being exposed to red light (λ ≥ 650 nm) in oxygen-free solutions, chlorophyll a dimers harbored by BoWSCP holoproteins (from Brassica oleracea var. botrytis) have sensitized the reduction of cytochrome c. According to absorption and circular dichroism spectroscopy data, the photochemical process did not significantly impair the structure of chlorophyll a molecules as well as their dimers harbored by BoWSCP protein. Adding tris(hydroxymethyl)aminomethane as an electron donor for chlorophyll recovery stimulated the photoreduction of cytochrome c.
DISCOVERY OF SIBOGLINIDS (ANNELIDA, SIBOGLINIDAE) IN THE ESTUARIES OF THE LARGEST ARCTIC RIVERS ARE ASSOCIATED WITH PERMAFROST GAS HYDRATES
Authors: Karaseva N. P. , Rimskaya-Korsakova N. N. , Kokarev V. N. , Simakov M. I. , Smirnov R. V. , Gantsevich M. M. , Malakhov V. V.
Published: April 2024

In the estuaries of the largest Arctic rivers, namely, the Yenisei, Lena and Mackenzie, marine worms of the family Siboglinidae have been found. Their metabolism is provided by symbiotic chemoautotrophic bacteria. The strong salinity stratification characteristic of the estuaries of the largest Arctic rivers ensures high salinity at depths of 25–36 m, where siboglinids were found. High concentrations of methane necessary for the metabolism of siboglinids arise because of dissociation of permafrost gas hydrates under the influence of river runoff in the conditions of Arctic warming
PROGNOSTIC OF YIELD OF POTATOES OF PROMISING DOMESTIC VARIETIES UNDER THE IMPACT OF STRESS ABIOTIC FACTORS
Authors: Rozentsvet O. A. , Bogdanova E. S. , Nesterov V. N. , Bakunov A. L. , Milekhin A. V. , Rubtsov S. L. , Dmitrieva N. N. , Shevchenko S. N.
Published: April 2024

Twenty four potato varieties (Solanum tuberosum L.) differing in ripening groups (early, middle-early and mid-season-ripening) were studied. Potatoes were grown in the conditions of the Middle Volga region of Russia. It was found statistically that the yield (t/ha) of early and mid-season-ripening varieties was negatively correlated with the increase in average temperatures during the growing season from May to August (R = –0.97, P = 0.04). Soil moisture content at a depth of 20 cm was positively correlated with the yield of middle-early varieties (R = 0.97, P = 0.04). A soil moisture content increase was beneficial to average tuber weight (R = 0.98, P = 0.04), but only in the middle-early and mid-season-ripening groups. However, the soil moisture content and the tuber numbers in mid-season-ripening varieties had a negative correlation (R = –0.96, P = 0.05).
FLUCTUATIONS IN THE RATE OF RADIOACTIVE DECAY OF THE NATURAL POTASSIUM-40 ISOTOPE CAN POTENTIALLY AFFECT THE PERIODIC “SPONTANEOUS” ACTIVITY OF ANIMALS
Authors: Diatroptov M. E. , Surov A. V.
Published: April 2024

The body temperature rhythms in laboratory mice C57Bl/6 and common greenfinches (Chloris chloris) and the moments of feeding by common starlings (Sturnus vulgaris) have been compared with the intensity of fluctuations of 40К radioactive decay. It was found that body temperature changes in greenfinches and mice positively correlate with the intensity of fluctuations of 40K radioactive decay. The method of superimposed epochs shows that the increase of body temperature in mice, reflecting the phase of the beginning of sleep/wake cycle activity, as well as food intake by starlings are observed at an increase in the intensity of 40K radioactive decay. Thus, animal activity in the ultradian range of periods may be related to external quasi-rhythmic physical influences, rather than determined only by endogenous processes. Given the extremely low dose of natural 40К exposure, a factor that can cause observed radioactivity fluctuations may be biotropic.
CAN SHREWS AVOID COMPETITION WHEN VIOLATING THE HUTCHINSON’S ECOLOGICAL RULE?
Authors: Vasil’ev A. G. , Bol’shakov V. N. , Vasil’eva I. A. , Kourova T. P.
Published: April 2024

It is established that the rule of G. Hutchinson’s idea of the ratio of body weight and size and foraging organs of similar species is not fully respected when comparing the species of shrews of the genus Sorex. The similarity of the centroid sizes of the mandible of large species S. isodon and S. araneus was revealed. By methods of geometric morphometrics, differences in the shape of the mandible, which is actively used in foraging, have been established between the species. Interspecific differences in mandibular indices reflecting trophic specialization and functional features of mandibles were found. Therefore, shrews can avoid competition even if Hutchinson’s rule is violated, and not so much due to the size, but due to the transformation of the lower jaw, its specialization, methods of capturing prey and changing the diet. Consequently, Hutchinson’s ecological rule is not mandatory, but only one of the conditions for reducing competition between closely related species.