bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of the Component Ratio in the Ti–B System on the Structure and Properties of Materials Fabricated by SHS Extrusion
Authors: Konstantinov A. S. , Chizhikov A. P. , Antipov M. S. , Bazhin P. M.
Published: April 2024

We studied how the ratio of precursor titanium and boron powders influenced the combustion temperature and combustion velocity in the high-temperature self-propagating synthesis (SHS) mode, and the microstructure, phase composition, and mechanophysical properties of rods fabricated by SHS extrusion. The subject matters of the study were materials for which the as-batch phase compositions of products were TiB–(20–40) wt % Ti. The formation of boron solid solution in titanium was considered. Scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and mechanical measurements implied the texture of the prepared materials (TiB whiskers were aligned in the direction in which the external pressure was applied). In all of the composites studied, the conductivity was close to the conductivity of undoped titanium; the electrical resistance increased slightly in response to increasing boron weight fraction. The three-point bending strength of the material increased by a factor of 1.7 at most as the weight fraction of boron solid solution in titanium increased from 20 to 40 wt %.
Derivatives of the closo-Decaborate Anion with Pendant Functional Groups as Inhibitors of Viral Replication
Authors: Grebennikova T. V , Avdeeva V. V. , Malinina E. A. , Zhizhin K. Yu. , Kuznetsov N. T. , Matveev E. Yu. , Garaev T. M. , Novikov S. S. , Nichugovskii A. I. , Sokolov I. E. , Larichev V. F. , Lebedeva V. V.
Published: April 2024

The reaction between the 1,4-dioxane derivative of the closo-decaborate anion [2-B10H9O(CH2)4O]– with cyanide, hydrophthalate, and hydroiminoacetate ions has been studied. Alkali metal salts (K, Na, and Cs) of the closo-decaborate anion derivatives with pendant groups –NHCH2CH2NH2-, –OOC(o-C6H4)COOH-, –OOCCH2NHCH2COOH-, –OCH2CH2OH-, –CN-, –SCN-, and –SH- have been isolated. All compounds have been shown to have extremely low cytotoxicity (CT50 ~ 1000 μg/mL). It has been found that compounds Na2[B10H9O(CH2)2O(CH2)2SCN] and Na2[B10H9O(CH2)2O(CH2)2CN] exhibit activity and selectivity in vitro against the modern strain of SARS-CoV-2 coronavirus (IC50 312 and 625 μg/mL, respectively). In relation to influenza A virus and rabies virus, the compounds show weak antiviral activity at high concentrations (1250 μg/mL), i.e. show no selective effect on the reproduction of these viruses.
Synthesis of Hydroxylapatite Substituted with REE Ions (La3+ and Y3+): Composition, Structure, and Properties
Authors: Golovanova O. A.
Published: April 2024

Substituted hydroxylapatites (HAs) containing various La3+ or Y3+ percentages were prepared. X‑ray powder diffraction, Four-transform IR spectroscopy, and optical spectroscopy verified the formation of substituted hydroxylapatites (La–HA and Y–HA). Inductively coupled plasma atomic emission spectrometry (ICP–AES) verified the presence of REE ions in the solids. Changes in the unit cell parameters of the prepared phases indicated that the REE ions substituted for Ca2+ ions in the hydroxylapatite structure. The lanthanum or yttrium percentage in precipitates increased in response to increasing REE salt concentration (within 1–5 wt %) in the initial solution as shown by chemical analysis; this brought about a decrease in the ratio Ca/P compared to the stoichiometric ratio (1.67). The solubility of the synthesized samples was studied, and it appeared that the cation-substituted hydroxylapatites were less soluble than undoped HA was.
Mixed Ligand Zinc Complexation with Ornithine and Histidine in Aqueous Solution
Authors: Nikitina M. G. , Gruzdev M. S. , Pyreu D. F.
Published: April 2024

The formation of mixed-ligand complexes of various compositions in the Zn–L-histidine (His)–L-ornithine (Orn) system has been studied by pH-metry, calorimetry, and NMR spectroscopy. The thermodynamic parameters (log K, ΔrG0 ΔrH, ΔrS) of the reactions of their formation at 298.15 K and ionic strength I = 0.5 (KNO3) have been calculated. Based on the comparative analysis of thermodynamic parameters, the most probable method for the coordination of amino acid residues in mixed complexes has been proposed.
Spectral Studies of Coordination of 1-Methyl-2-(pyridin-4-yl)-3,4-fullero[60]pyrrolidine by Highly Substituted Cobalt(II) Porphyrin
Authors: Bichan N. G. , Mozgova V. A. , Ovchenkova E. N. , Gruzdev M. S. , Lomova T. N.
Published: April 2024

A new dendrimeric cobalt(II) complex CoP has been obtained when reacting (5,15-bis[3,5-bis(tert-butyl)phenyl]-10,20-bis{4,6-bis[3,5-bis(3,6-di-tert-butylcarbazole-9-yl)phenoxy]pyrimidin-5-yl}porphine with Co(AcO)2·4H2O. The process of two-step two-way coordination of 1-methyl-2-(pyridin-4'-yl)-3,4-fullero[60]pyrrolidine (PyC60) with cobalt(II) porphyrin ends with the formation of a stable 1 : 2 complex, a triad of composition (PyC60)2CoP. The process has been completely kinetically described using UV-vis and fluorescent spectroscopy data. The stability constant (K) of the coordination complex is (9.9 ± 2.4) × 108 L2 mol–2 (log K = 9.0). The chemical structure of the triad has been determined by UV-vis, 1H NMR, and IR spectroscopy. The effect of PyC60 fluorescence quenching in the triad has been found and studied, and the static mechanism of the quenching process has been substantiated. The result can be used in optoelectronics to optimize the structures of donor–acceptor systems with the property of photoinduced electron transfer.
Synthesis and Structure of the Dicarboxyl-Terminated Iron(II) Tris-Glyoximates with Linear and Angular Geometry of their Molecules
Authors: Chuprin A. S. , Dudkin S. V. , Vologzhanina A. V. , Voloshin Ya. Z.
Published: April 2024

Template condensation of the chelating α-dioximate ligand synthon—glyoxime and the appropriate cross-linking agent—monofunctionalized boronic (3-carboxyphenylboronic or 4-carboxyphenylboronic) Lewis acid in a boiling nitromethane as a solvent on the iron(II) ion as a matrix afforded the dicarboxyl-terminated iron(II) tris-glyoximates with functionalizing meta- and para-substituents in their apical boron-based aromatic fragments. The composition and structure of these macrobicyclic complexes were confirmed using elemental analysis, UV-vis, 1H and 13C{1H} NMR spectra. Their crystal and molecular structures were obtained by the single crystal X-ray diffraction experiments. Asymmetric units of their crystals contain, besides of a clathrochelate molecule, two solvate molecules, which form hydrogen bonds with its functionalizing carboxyl groups. The C–O bond lengths in these terminal groups and a possibility of localization of hydrogen atoms on the difference Fourier maps clearly demonstrate that the formation of such associates does not include a deprotonation of the macrobicyclic complex and its intracomplex molecules remain neutral. The encapsulated iron(II) ion in their molecules occupies a centre of its FeN6-coordination polyhedron. Its geometry is intermediate between a trigonal prism (TP, the distortion angle φ = 0°) and a trigonal antiprism (TAP, φ = 60°); the values of φ are equal to 17.1 and 18.9°, respectively. Fe–N distances vary from 1.901(2) to 1.924(2) Å, thus suggesting a low-spin diamagnetic state of the encapsulated iron(II) ion. The C=N bonds in the donor oxime groups are shortened, while the С–С bonds in the chelating glyoximate fragments are elongated, as compared with those in their aliphatic analogs. Free rotation of the apical aromatic substituents at the cross-linking boron atoms around the ordinary B–C bonds caused the absence of their coplanarity. The intramolecular distances С···С between the terminal carboxyl groups in the apical cross-linking fragments are equal to 15.693(4) and 17.888(3) Å for the clathrochelate meta- and para-isomers, respectively. The aforementioned rotation allows to achive an angular geometry of the prospective meta-dicarboxyloclathrochelate ligand with a formation of ∠C···Fe···C close to 145° between its terminal O‑donor carboxyl groups. This complex can play a role of both the angular and linear 3D-ligands, while its clathrochelate para-substituted isomer seems to be the prospective linear metalloligand.
Synthesis, Physicochemical Properties, and Biological Activity of the Bentonite/Iron Oxide Composite
Authors: Alekseeva O. V. , Smirnova D. N. , Noskov A. V. , Kuznetsov O. Yu. , Kirilenko M. A. , Agafonov A. V.
Published: April 2024

The powdered bentonite/iron oxide composite material was synthesized by chemical co-precipitation. The grain size composition, morphology, crystal structure, porosity, and thermal stability of the obtained powder were investigated. It was established that iron oxide exists in the composite as the maghemite/magnetite solid solution with the formula Fe2.950O4. An increase in the viability of the bacterium Escherichia coli M-17 after culturing in the nutrient medium in the presence of the synthesized bentonite/iron oxide powder was found.
Noble Metal Porphyrin Complexes. Intermediates of Catalytic Processes (A Review)
Authors: Tyulyaeva E. Yu.
Published: April 2024

A wide variety of oxidation states and coordination numbers of complexing cations, various redox properties, high stability of the coordination center, as well as a unique electronic structure determine the catalytic activity of porphyrin complexes of noble metals in various reactions with organic substrates. This review presents the types of catalytic reactions involving compounds of ruthenium, rhodium, iridium, palladium, platinum, and gold with porphyrins, with an emphasis on the features of intermediates depending on the nature of the metal, electronic and steric effects of peripheral substituents of the macrocycle. The presented data provide a theoretical basis that can contribute to the development of innovative materials for catalysis based on metalloporphyrins, as well as the creation of new homogeneous and heterogeneous catalysts.
Investigation of the KNd(SO4)2·H2O–SrSO4·0.5H2O System
Authors: Bushuev N. N. , Tatosyan G. K.
Published: April 2024

The cocrystallization of potassium, neodymium, and strontium sulfates from aqueous solutions has been studied using X-ray powder diffraction, thermogravimetry, energy-dispersive X-ray spectral analysis, and electron microscopy. Extensive solid solutions based on trigonal KNd(SO4)2⋅H2O have been found to exist in the concentration range 100–20 mol % of the KNd(SO4)2⋅H2O–SrSO4⋅0.5H2O system. The unit cell parameters of the solid solutions have been determined. Two phases have been discovered: trigonal KNd(SO4)2⋅H2O (space group P3121) and monoclinic KNd(SO4)2⋅H2O (space group P21/c1). The heterovalent substitution scheme 2Sr2+ → K+ + Nd3+ stabilizes the structure of solid solutions based on the isostructural KNd(SO4)2⋅H2O and SrSO4⋅0.5H2O trigonal phases.
Thermal Stability of Complex Aluminates in the La2SrAl2O7–Ho2SrAl2O7 System
Authors: Popova V. F. , Tugova E. A.
Published: April 2024

Continuous solid solutions of two-layer (La1 – xHox)2SrAl2O7 aluninates, which are Ruddlesden–Popper phases, have been found to exist in the La2SrAl2O7–Ho2SrAl2O7 system at temperatures above 1515°С. The (La1 – xHox)2SrAl2O7 complex aluminates crystallize in tetragonal crystal system (space group I4/mmm). A phase transformation scheme has been proposed for the La2SrAl2O7–Ho2SrAl2O7 system with the unlimited mutual solubility of the components at high temperatures and with a decomposition area below the critical temperature Тcr = 1515°С.
Optimization of Liquid Complex Fertilizer Formulations Using Phase Diagrams of Multicomponent Systems
Authors: Kudryashova O. S. , Kistanova N. S. , Elokhov A. M.
Published: April 2024

The paper describes a method for the optimization of liquid complex fertilizer (LCF) formulations using phase diagrams of multicomponent water–salt systems. The chosen optimization criteria are the concentration of solution and the set of salts that provide the most concentrated fertilizer at the set ratio N : P2O5 : K2O. The opportunities of the method are shown for exemplary three- and four-component systems. The compositions of eutonic solutions and the ratios of nutrients calculated for them are given. Experimental data confirm the influence of the salt set and a solubilizer (urea) on the solution concentration. The number of optimal compositions becomes greater as the number of components in the system increases. Phase diagrams help to determine whether the liquid fertilizer composition belongs to the 15 homogeneous regions and thereby to guarantee its long-term storage stability.
Synthesis and Luminescent Properties of Multicomponent Garnets Y3MgGa3SiO12, Y3MgGa2AlSiO12, and Y3MgGaAl2SiO12 Doped with Cr3+ Ions
Authors: Khaidukov N. M. , Nikonov K. S. , Brekhovskikh M. N. , Kirikova N. Yu. , Kondratyuk V. A. , Makhov V. N.
Published: April 2024

Ceramic samples of Y3MgGa3SiO12, Y3MgGa2AlSiO12, and Y3MgGaAl2SiO12 multicomponent garnets doped with 0.2 at % Cr3+ have been obtained by high-temperature solid-state synthesis. In the luminescence spectra of the synthesized garnet samples, overlapping broadband luminescence is observed in the far red spectral region caused by the 4T2 → 4A2 transition in Cr3+ ions, and a narrow band is observed in the range of 690–700 nm, corresponding to the zero-phonon line of the 2Е → 4A2 transition in Cr3+. The narrow-band and broad-band parts of the spectra are attributed to radiation from two different types of chromium centers, which are in octahedral coordination with different distortion degrees and strength of the crystal field. This results from the presence of two ions at the octahedral position of these garnets, which differ significantly in crystal chemical properties, namely, Mg2+ and Ga3+ (Al3+). The studied phosphors, which have broadband luminescence in the phytoactive far red region of the spectrum, have the potential for use in greenhouse LED lamps.
Sodium Chromium Arsenate Phosphates: Preparation, Structure, and Thermal Properties
Authors: Pyaterikov E. A. , Pet’kov V. I. , Fukina D. G. , Borovikova E. Yu.
Published: April 2024

Arsenate phosphates(1.75 ≤ x ≤ 3.0) were prepared by coprecipitation. Their unit cell parameter was a linear function of composition: a (Å) = 0.0967x + 11.873. The Na3Cr2(AsO4)2PO4 crystal structure was refined by the Rietveld method; the coordinates of basal atoms and bond lengths were calculated. A garnet solid solution crystallizes at 600–650°C; transition to a high−temperature rhombohedral structure occurred at 994–1044°C. The thermal expansion of the low-temperature phase having a garnet structure was studied in the range from –130 to 200°C. The solid solution samples expanded isotropically and had small thermal expansion.
INVESTIGATION OF PHASE EQUILIBRIA IN SECTIONS OF THE CALCIUM NITRATE–ISOPROPANOL–WATER SYSTEM AT TEMPERATURES OF 0...-39°C
Authors: FROLOVA E. A. , KONDAKOV D. F. , KIRILENKO I. A. , BALAKAEVA I. V. , DANILOV V. P.
Published: April 2024

Phase equilibria in sections of the Ca(NO3) system are investigated2–i-PrOH–H2O at temperatures below 0 °C and anti-icing properties of calcium nitrate and isopropanol compositions with a component ratio from 1 : 3 to 3: 1, temperatures, composition of eutectic with ice and melting ability of nitrate-isopropanol compositions at temperatures of -5 and -10 °C. Compositions characterized by good anti-icing properties have been identified.
Electron Transport in Perovskite-Type Ca0.5 – xSr0.5LuxMnO3 – δ Manganites
Authors: Konstantinova E. I. , Litvinov V. A. , Koryakov A. D. , Leonidov I. A.
Published: April 2024

Perovskite-type Ca0.5 – xSr0.5LuxMnO3 – δ (x = 0.05, 0.10, 0.15, and 0.20) manganites have been prepared in air using a citrate–nitrate process for preparing precursors. At room temperature, the x = 0.05, 0.10, and 0.15 samples have an orthorhombic structure (space group Pbnm); when x = 0.2, a tetragonal structure (space group I4/mcm) is formed. The increase in unit cell volume in response to rising lutetium concentration in the samples is due to an increase in Mn3+ concentration necessary to ensure n-type electrical conductivity σ. The temperature-activated electrical conductivity is consistent with the adiabatic transport mechanism of small polarons. The increase in magnitude of the Seebeck coefficient S in response to rising temperature is due to the decrease in the concentration of Mn3+ ions via their disproportionation to Mn2+ and Mn4+ ions. The S(T) and σ(T) temperature dependences under the condition where δ ⁓ 0 have been used to calculate the equilibrium constants of the disproportionation reaction, charge carrier concentrations and mobilities.
Zinc(II) Complex with 2-Hydroxy-5-ethylphenylphosponic Acid: Synthesis, Structure, Toxicity, and Accumulation in HeLa Cells
Authors: Ivanova I. S. , Tsebrikova G. S. , Ilyukhin A. B. , Solov’ev V. P. , Lapshina M. A. , Rogacheva Yu. I. , Pyatova E. N. , Baulin V. E. , Tsivadze A. Yu.
Published: April 2024

A complex of zinc(II) with 2-hydroxy-5-ethylphenylphosphonic acid (H3L) of the composition [Zn(H2L)2(Н2О)2][Zn(HL)(Н2О)]·H2O (I) was synthesized, the structure of which was established based on data of X-ray diffraction and elemental analysis, quantum chemical calculations, as well as IR and electron absorption spectroscopies. The stability constants of H3L acid complexes with zinc(II) perchlorate in water were determined by potentiometric titration. The cytotoxic properties of H3L acid and complex I were studied for the first time on HeLa cells (human cervical adenocarcinoma). The results on the accumulation of complex I in HeLa cells were obtained by laser confocal microscopy.
Optical Properties of Fluorozirconate Glasses Doped with Chromium Ions
Authors: Batygov S. Kh. , Brekhovskikh M. N. , Moiseeva L. V. , Vinokurova V. V. , Kirikova N. Yu. , Kondratyuk V. A. , Makhov V. N.
Published: April 2024

Chromium trifluoride-doped fluoride glasses in the ZrF4–BaF2–LaF3–AlF3–NaF (ZBLAN) system with partial substitution of fluorine for chlorine have been synthesized. The spectral data obtained confirm that chromium ions enter the glass structure and exhibit broadband luminescence caused by the 4T2 → 4A2 transition in the Cr3+ ion. The observed long-wavelength shift of the broadband luminescence band and Cr3+absorption bands in fluoride–chloride glass compared to fluoride glass corresponds to the expected behavior of the Cr3+ luminescence and absorption spectra when fluoride ions are replaced by chloride ions, which should lead to a weakening of the strength of the crystal field acting on Cr3+ ions. At room temperature, the luminescence of Cr3+ ions at 888 and 908 nm is strongly quenched due to the thermally stimulated nonradiative transition from the 4T2 excited state to the 4A2 ground state.
On the Interaction of Gold(III) Complexes with Human Serum Albumin
Authors: Mironov I. V. , Kharlamova V. Yu.
Published: April 2024

The interaction of gold(III) complexes (Au(bipy), Au(phen), and Au(dien-H)Cl+) with human serum albumin (HSA) was studied in aqueous solutions (pH 7.4, CNaCl = 0.2 M, CAu = (2–10) × 10–5 M, CHSA 6 × 10–4 M) at 25°C. In all cases, gold(III) is reduced to gold(I), which forms a complex with HSA. When an excess of HSA is present, the time required for complete transformation of the complexes does not exceed 1 h. In addition, it was shown that the redox reaction of gold(III) complexes with cysteine is much faster than the reaction with methionine.
Structure of the Local Environment and Hyperfine Interactions of 57Fe Probe Nuclei in AMnO3 (A = Sc, In)
Authors: Sobolev A. V. , Šandalova S. , Smirnova M. N. , Belik A. A. , Glazkova Ya. S. , Presniakov I. A.
Published: April 2024

The results of a Mössbauer study of hyperfine interactions of 57Fe probe nuclei in isostructural hexagonal manganites h-ScMnO3 and h-InMnO3 are presented. The results of measurements of the Mössbauer spectra at T TN, as well as calculations of the parameters of the electric field gradient tensor at 57Fe nuclei, demonstrated different behavior of the probe iron ions in these isostructural systems, reflecting the difference in the processes of defect formation in their crystal lattices. On the contrary, measurements at T TN did not reveal any differences in the local magnetic structure of 57Fe probe atoms in these oxides.
Phase Equilibria in the Cu2Se–Cu8SiSe6–Cu8GeSe6 System
Authors: Bairamova U. R. , Babanly K. N. , Mashadieva L. F. , Yusibov Yu. A. , Babanly M. B.
Published: April 2024

Phase equilibria in the Cu2Se–Cu8SiSe6–Cu8GeSe6 area of the Cu2Se–SiSe2–GeSe2 system have been studied using differential thermal analysis (DTA), X-ray powder diffraction analysis (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDX). The results served to plot a Т–х diagram of the Cu8SiSe6–Cu8GeSe6 boundary system, a series of polythermal sections, and a 300-K isothermal section of the phase diagram and a liquidus surface projection for the title system. The primary crystallization and homogeneity fields of phases, and the characters and temperatures of invariant and monovariant equilibria have been determined. In the Cu8SiSe6–Cu8GeSe6 boundary system, continuous solid solutions have been found to exist between the high-temperature phases of the terminal compounds and extensive homogeneity area based on their low-temperature phases were found. The crystal lattice types and unit cell parameters have been determined for the terminal compounds and both phases of solid solutions using X-ray powder diffraction data. The prepared phases of variable composition are of interest as environmentally friendly functional materials.
Anti- and Pro-Oxidant Properties of Cerium Oxide Nanoparticles Functionalized with Gallic Acid
Authors: Sozarukova M. M. , Proskurnina E. V. , Mikheev I. V. , Polevoy L. A. , Baranchikov A. E. , Ivanov V. K.
Published: April 2024

Cerium oxide sols functionalized with gallic acid (GA) in various molar ratios (CeO2@GA, 1 : 1, 1 : 2, and 2 : 1) were synthesized for the first time. The antioxidant activity of the obtained nanomaterials towards alkylperoxyl radicals was analyzed by the luminol-enhanced chemiluminescence assay. It was shown that CeO2@GA composites possess different types of redox activity, combining antioxidant and pro-oxidant properties. It was found that the redox activity of CeO2@GA composites is largely due to the ligand, gallic acid. Meanwhile, the immobilization of gallic acid on the surface of cerium dioxide nanoparticles leads to a decrease in its antioxidant and pro-oxidant activities. This effect is most pronounced in the case of the 2 : 1 CeO2@GA sol, in which the antioxidant and pro-oxidant capacities of gallic acid have decreased by 40 ± 3 and 58 ± 9%, respectively.
New Method for Synthesis of Substituted 1-Amidine-closo-decaborates [1-B10H9NH=C(R1)NHR2] (R1 = Me, iPr, Ph; R2 = nBu, Bn)
Authors: Bil’bulyan A. A. , Nelyubin A. V. , Selivanov N. A. , Bykov A. Yu. , Klyukin I. N. , Zhdanov A. P. , Zhizhin K. Yu. , Kuznetsov N. T.
Published: April 2024

The process of nucleophilic substitution of the phenyliodonium substituent in the [1-B10H9IPh]– anion with primary amines in organic nitriles has been studied. It has been shown that the reaction proceeds with the formation of a mixture of products, namely, 1-monoalkylammonio-closo-decaborate and the corresponding amidine, which is formed when an amine molecule is added to the nitrile. The resulting products have been characterized by 1H, 11B, 13C NMR spectroscopies, IR absorption spectroscopy, and high-resolution ESI mass spectroscopy.
Thermophysical Properties of Neodymium and Gadolinium Zirconate Hafnates
Authors: Gagarin P. G. , Guskov A. V. , Guskov V. N. , Khoroshilov A. V. , Gavrichev K. S.
Published: April 2024

Pyrochlore-type neodymium and gadolinium zirconate hafnates have been prepared and identified. The heat capacities of the prepared samples have been measured by differential scanning calorimetry in the range 310–1800 K. Temperature-dependent cubic unit cell parameters have been determined and thermal expansion coefficients assessed in the range 298–1273 K using high-temperature X-ray diffraction. The thermal diffusivity of the samples was measured by the laser flash method, and the temperature-dependent thermal conductivity was calculated taking into account the porosity of the samples.
Synthesis and Magnetic Resonance of Lanthanum Manganites Doped with Potassium Ions
Authors: Steblevskaya N. I. , Ziatdinov A. M. , Belobeletskaya M. V. , Saenko N. S.
Published: April 2024

Manganites doped with potassium ions La1 – xKxMnO3, where х = 0.0, 0.1, and 0.15, have been obtained by extraction-pyrolytic method at low temperature. The compounds have been studied by X-ray powder diffraction, electronic paramagnetic and ferromagnetic resonances. Unit cell parameters of La1 – xKxMnO3 samples have been calculated. According to magnetic resonance spectroscopy, La1 – xKxMnO3 exhibits phase delamination into paramagnetic and ferromagnetic phases. The fraction of the latter phase increases when temperature decreases. The temperature of transition from paramagnetic into ferromagnetic phase (Curie temperature, TC) for La1 – xKxMnO3 is –17.4, –13.7, and –4.8°С at х = 0.0, 0.1, and 0.15, respectively. The reason of symbate change in TC and potassium ion concentration in La1 – xKxMnO3 is supposed to be the change in the content of ferromagnetic pairs Mn3+–О2––Mn4+ in the manganites.
Sorption of Radionuclides on Amorphous and Crystalline Cerium(IV) Phosphates
Authors: Kozlova T. O. , Khvorostinin E. Yu. , Rodionova A. A. , Vasilyeva D. N. , Baranchikov A. E. , Ivanov V. K.
Published: April 2024

The sorption properties of amorphous cerium(IV) hydrogen phosphate and crystalline phases NH4Ce2(PO4)3, (NH4)2Ce(PO4)2·H2O, and Ce(OH)PO4 towards the 243Am(III), 232Th(IV), 237Np(V), and 233, 238U(VI) radionuclides were studied in aqueous media at pH 1, 4, 7, and 10 for 24 h. The highest degree of sorption (up to 100%) was found for amorphous cerium(IV) hydrogen phosphate. The pH dependences of radionuclide sorption for crystalline compounds were shown to be similar to one another: the highest sorption was observed at pH 7 (up to 100% for 243Am(III)), while the lowest values were observed for pH 10 and 1. An exception was provided by 237Np(V), the sorption of which was close to zero in the pH range of 1–7 and reached 60% at pH 10. Keeping amorphous and crystalline cerium(IV) phosphates in acid medium leads to quantitative desorption of all of the tested radionuclides within the first 5 h.
Solubility of Scandium Cesium Double Sulfate CsSc(SO4)2 in Sulfuric Acid Solutions
Authors: Pasechnik L. A. , Medyankina I. S. , Tyutyunnik A. P. , Bamburov V. G.
Published: April 2024

Cesium sulfatoscandate CsSc(SO4)2 (space group P, a = b = 5.0971(1) Å, c = 8.6924(5) Å, V = 195.580(2) Å3, Z = 1) has been crystallized from aqueous solutions in layered hexagonal prisms sized up to 50 µm and up to 2–5 µm thick. Its water solubility is 0.0104 mol/L at 25 ± 1°С. A way to reduce the solubility of scandium as CsSc(SO4)2 is to increase acidity to 3.5–5.5 М H2SO4 and add Cs2SO4. Experimental evidence is supported by calculations that took into account changes in the ionic strength of the solution and the influence of the simultaneous presence of Cs+ andions. The results will be useful for those who will study the behavior of rare-metal compounds having similar properties and their separation.
Phase Equilibria and Chemical Reactions in the Mn2O3–ZnO–SiO2, Mn3О4–ZnO–SiO2 и MnO–ZnO–SiO2 Systems
Authors: Zaitseva N. A. , Samigullina R. F. , Ivanova I. V. , Krasnenko T. I.
Published: April 2024

The subject matter of this work was the triangulation of the Mn2O3–ZnO–SiO2, Mn3O4–ZnO–SiO2, and MnO–ZnO–SiO2 systems and the determination of phase transformations to yield Zn2 – 2хMn2хSiO4 solid solution. Equilibrium phase diagrams have been plotted taking into account the existence temperatures of each of the manganese oxides, phase compositions of the constituent binary systems, and checkup points, whose phase compositions helped us to determine the positions of secondary triangles. The phase compositions of reaction products of the terminal oxides and the phase transformation sequence during Zn2 – 2хMn2хSiO4 synthesis were monitored by X-ray powder diffraction and thermal analysis. Phase ratios in the MnOх–ZnO–SiO2 system are caused by the charge states of manganese ions changing in response to rising temperature. The triangulation of the Mn2O3–ZnO–SiO2 system at 800°С is determined by the ZnMn2O4–Zn2SiO4 tie-line and partitions the system to the ZnO–Zn2SiO4–ZnMn2O4, Zn2SiO4–ZnMn2O4–SiO2, and ZnMn2O4–SiO2–Mn2O3 simplex triangles. The Zn2 – 2хMn2хSiO4 solid solution with an extent limited to Zn1.6Mn0.4SiO4 is formed at temperatures above 1000°С. The triangulation of the MnO–ZnO–SiO2 ternary system is determined by the Zn1.6Mn0.4SiO4–ZnO–MnSiO3 simplex triangle.
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Synthesis and Ionic Conductivity of Complex Phosphates Li1 + xTi1.8 – xFexGe0.2(PO4)3 with NASICON Structure
Authors: Stenina I. A. , Taranchenko E. O. , Ilin A. B. , Yaroslavtsev A. B.
Published: April 2024

Phosphates Li1 + xTi1.8 – xFexGe0.2(PO4)3 (x = 0.1–0.3) with the NASICON structure have been prepared and studied for the first time. It has been shown that co-doping with germanium and iron leads to significant increase in the ionic conductivity of the prepared materials at low degrees of titanium substitution. The influence of the synthesis method (solid-state and sol-gel) and conditions of precursor processing on the ionic conductivity of the materials has been studied. Optimum conditions for the mechanical processing of precursors have been found to obtain ceramics with the highest conductivity. Li1.2Ti1.6Fe0.2Ge0.2(PO4)3 prepared by the solid-state method exhibits the highest ionic conductivity at room temperature (1.7 × 10–4 S/cm) among all samples.
Synthesis of Two-Dimensional NiO Nanostructures by a Combination of Programmable Chemical Deposition and Hydrothermal Treatment
Authors: Simonenko T. L. , Dudorova D. A. , Simonenko N. P. , Simonenko E. P. , Kuznetsov N. T.
Published: April 2024

The synthesis of two-dimensional NiO nanostructures by programmable chemical deposition in combination with the hydrothermal treatment of intermediates in distilled water and in aqueous ammonia solution was studied. Simultaneous thermal analysis was used to determine the dependence of thermal stability and sorption capacity of particles of the intermediates on the parameters of their hydrothermal treatment and on the composition of the dispersion medium. The results of IR spectroscopy and X-ray diffraction analysis helped us to recognize the crystal structure specifics and the set of functional groups for intermediates and for NiO nanopowders formed on their basis. The average size of the coherent scattering regions (CSRs) of the manufactured nickel oxide powders varied from 4.0 ± 0.5 to 8.6 ± 0.8 nm depending on the hydrothermal treatment parameters. Scanning (SEM) and transmission (TEM) electron microscopy showed that the recrystallization of NiO nanoparticles can be tuned depending on the synthesis parameters to yield two-dimensional nanostructures of various shapes and required sizes, ranging from nanosheets of chaotic geometry to flat hexagons with a variable diameter. Due to their anisotropic microstructure, the manufactured nanomaterials can be effectively used in the fabrication of functional components for advanced alternative energy devices (supercapacitor electrodes, solid oxide fuel cells, etc.), including the use of printing technologies.
Hierarchically Organized MoS2 Films as Promising Electrodes for Flexible Supercapacitors
Authors: Simonenko T. L. , Simonenko N. P. , Zemlyanukhin A. A. , Gorobtsov F. Yu. , Simonenko E. P. , Kuznetsov N. T.
Published: April 2024

The formation of hierarchically organized MoS2 films on various substrates by a hydrothermal method was studied. The influence of synthesis conditions and the substrate (a glass or a flexible carbon paper substrate) on the crystal structure of sulfide films was determined using X-ray powder diffraction (XRD). Scanning electron microscopy (SEM) showed that the films on glass substrates comprised structurally different elements, namely a continuous dense layer of spherical nanoparticles on the surface of which hierarchically organized globular agglomerates of two types are arranged. A molybdenum disulfide shell about 1.5 μm thick, consisting of hierarchically organized nanosheets less than 10 nm thick, was formed on the surface of carbon fibers that make up the carbon paper. Elemental mapping was used to evaluate the homogeneity of the MoS2 film formed on the carbon paper. Atomic force microscopy (AFM) showed that an individual carbon fiber modified with a sulfide film had a mean square roughness of about 13 nm (over an area of about 100 μm2). According to Kelvin-probe force microscopy (KPFM) data, the electron work function of the material was 4.53 eV. The electrochemical characteristics of the manufactured flexible electrode based on a hierarchically organized molybdenum disulfide film were investigated. The specific capacitance and the stability of functional and microstructural properties of the manufactured supercapacitor electrode in 2000 charge–discharge cycles were evaluated. Thus, the proposed strategy is promising for the fabrication of efficient hierarchically organized MoS2 electrodes for flexible supercapacitors.
DFT Modeling of Isomerism of Doped Mg24L2 Clusters with Dopants L at the Surface and inside the Magnesium Cage
Authors: Charkin O. P.
Published: April 2024

The isomers of Mg24L2 nanoclusters with dopants L from the firt three periods (L = Li–Zn) in the exo- and endohedral positions of the magnesium cage have been calculated by the density functional theory (DFT) method. The effect of dopants on the structure, stability, and position on the energy scale has been studied. For the systems with atoms L = H, Li, Be N, Na, Co, and Cu, the “open” positions of dopants at the surface are more favorable, unlike their analogs with L = Be and B, for which the “closed” positions in the inner cavity of the cluster are more favorable and their promotion to the surface requires a significant energy input. For clusters with O, Si, P, S, and early 3d metal atoms, the differences in the energies of the exo- and endohedral isomers do not exceed a few kcal/mol. The atoms of the second half of the 3d series are characterized by their association into diatomic dopants L2. The results are compared with the data of similar DFT calculations of isomers of Al42L2 aluminum clusters with the same dopants L = Li–Zn and are of interest for modeling the mechanisms of catalytic hydrogenation of magnesium and aluminum nanoclusters at the molecular level.
Spatial organization of the bird assemblages of the Eastern Altai in the first part of summer
Authors: Bochkareva E. N. , Mitrofanov O. B.
Published: April 2024

The results of bird counts averaged over the first half of summer (May 16–July 15) in 1996, 2000–2002, 2007, 2008 and 2013 in the Eastern Altai are analyzed. The hierarchical classification of bird population has been compiled on the basis of cluster analysis. Its structure and the main environmental factors that determine the territorial heterogeneity of ornithocomplexes have been identified. It is shown that their variability in the East Altai and the Altai physiographic mountain region is generally similar in structure. The spatial-typological structure of the Eastern Altai bird population is close to a crescent in its configuration.
The dynamics of the orchid flora of Russia as revealed by comparison of the data before 1951 and in 1961–2010
Authors: Efimov P. G.
Published: April 2024

The study of the distributional changes is a perspective subject of botanical research. Such studies are of particular importance for diagnosis of decline, and can make an important input for the identification of specific factors affecting plant abundance and, in the future, to provide appropriate plant protection in situ. The aim of this study is to elucidate the distributional changes in Russian orchid flora based on historic distributional data. In our country, these data are provided primarily by herbarium materials. This article deals with the distributional changes as revealed by comparing the dataset before 1951 and in 1961–2010. The taxa with statistically significant decrease and increase have been observed; for others, no significant changes were detected. The distributional changes are studied across Russia as a whole, and separately for some parts of the country. Cases where inconsistent dynamics across the country were revealed, are rare. The prospects for further research in this area are discussed, including the possibility of applying the same methodology for other groups of vascular plants in Russia.
Influence of the French scientific school on the development of bioacoustics in the Soviet Union (60–70s of the last century)
Authors: Nikol’skii A. A.
Published: April 2024

The influence of the French scientific school on the development of bioacoustics in the Soviet Union in the 1960–70s is discussed. The main influence on the development of Soviet bioacoustics was provided by the Laboratory of Physiological Acoustics at the National Institute for Agricultural Research of France, created and directed by René-Guy Busnel. Soviet bioacoustics adopted the research experience of France in three main areas: 1) acoustic orientation and signaling of insects; 2) theory and practice of acoustic repellents in agriculture and aviation; 3) sonar systems, acoustic communication and orientation of marine mammals, echolocation. The main research centers in the Soviet Union are listed and the role of Soviet scientists in the development of various areas of bioacoustics in the Soviet Union is considered.
Herbaria of Russia: The role in the study of biodiversity of the country, the problems of conservation and management
Authors: Garin E. V. , Garina D. V.
Published: April 2024

In order to preserve biodiversity on Earth, it is necessary to carry out an inventory of all forms of life as soon as possible, and this task is especially relevant for little-studied territories, including Russia. The terrestrial and aquatic ecosystems of Russia represent the largest array of natural extratropical ecosystems in Eurasia. To solve the problem of inventorying flora and fauna, biological collections are of particular importance; in a number of reviews by scientists (mainly foreign ones) the attention of the scientific and civil community is drawn to the problem of preserving and increasing the use of collections. The article examines the role of herbaria in the study of biodiversity in Russia based on a quantitative analysis of collections, their representation in various regions of the country, the degree of their digitalization and integration into the global world network of biological collections. It is concluded that the herbarium fund of Russia is insufficient in terms of the number of specimens and unevenly distributed across the regions, the smallest number of plant specimens is available for a number of regions of the north-east of Russia. About half of all Russian herbaria are not registered in Index Herbariorum, although the pace of digitalization of botanical collections in Russia has somewhat accelerated in recent decades. It also highlights the problem of the preservation of herbarium collections, outlines ways to solve it and prospects for the use of herbaria in the future. The authors believe that the priority measures should be: 1) the formation of a regulatory framework for working with biocollections, which, in particular, will make it possible to recognize herbarium collections as objects of cultural and scientific heritage, and provide special funding for collections; 2) introduction into the practice of centralized accounting of Russian herbaria and their inclusion in the international database; 3) a ban on writing off herbarium collections by organizations; 4) increasing the pace of digitalization of botanical collections; 5) staffing of herbaria by professional researchers; introducing of a herbarium course in specialized universities; 6) the allocation of separate rooms for herbariums, equipped with specialized cabinets and ventilation.
Adaptive reactions of ancient fossil organisms: Likely evolutionary causes of sociality emergence
Authors: Sumina E. L. , Sumin D. L.
Published: April 2024

The results of the study of stromatolites for the purposes of geology have shown the directed and irreversible nature of their evolution. Further detailed study of the structure made it possible to reveal the subordination of the structures of various hierarchical levels and the consistency of their changes over time, which indicates the presence of morphogenetic and adaptive capabilities in the macroscopic stromatolite-forming agent – the properties of an integral organism. This was in conflict with the ideas existing at that time about the impossibility of the formation of organized communities or multicellular organisms by prokaryotes. It was believed that the formation of multicellular organisms and any communities with developed communication requires a high structural complexity of the elements. Bacteria were considered as solitary or colonial organisms not having sufficient complexity. However, direct observation of their accumulations revealed signs of highly organized communities comparable in their integrity to organisms. This forces a different approach to the nature of the emergence of communities and the sources of their complexity. Based on the unity of the observed processes, in addition to the cyanobacteria themselves, data on other groups of bacteria, as well as on modular organisms and communities of multicellular eukaryotes, are considered.
Integral effect of a non-centralized biosystem parts interaction with the example of major hydroplasma flow formation in the shoots of colonial hydroid Dynamena pumila (L., 1758)
Authors: Marfenin N. N. , Dementiev V. S.
Published: April 2024

The emergence of the main hydroplasmic flows (HFs) in the shoot of colonial hydroids (Hydrozoa), flowing from it into the stolon and capable of transporting food particles along stolons to the opposite end of the non-centralized organism, is described. We developed a simple method for minute-by-minute visual registration of the direction of particles movement in hydroplasm in each shoot shaft module for 1.5 hours. The HFs entering the shoot are shown to be rhythmic (15.1 ± 5.0 min), but if the outgoing HFs are usually filled with food particles, the returning HFs, as a rule, contain few particles. There is more chaos in the pulsations of hydrants on the shoot than in the stem of the shoot, i.e. the period of receipt of HF from hydrants to the stem of the shoot varies significantly. Previously, it has been assumed that outgoing HFs are formed only under the influence of incoming ones, as a response to coenosarc stretching when hydroplasma enters the shoot (under the pressure of other pulsators in the colonial organism). However, it turned out that from the appearance of the incoming to the beginning of the outgoing HF, 5 minutes elapsed as an average. During this time, hydroplasma fills not only the stem of the shoot, but also the hydrants, which contract in response, although not simultaneously. The hydrants squeeze out the hydroplasma during compression into the stem of the shoot, after which the coenosarc of the shoot begins to shrink. It turned out that when taking into account the pulsations of hydrants for 3 minutes, a clear periodicity is registered, coinciding with the periodicity of HF emanating from the shoot, resulting from compression of the coenosarc of the stem. At the same time, hydroplasma cannot enter the hydrants until the end of the long phase of their compression. Otherwise, the movements of the hydroplasma would be limited only by the escape space. Thus, in a non-centralized system such as colonial hydroids organism, the coordination of pulsations of hydrants and coenosarc occurs with significant backlash. In the coenosarc, as a whole, the pulsations are rhythmic with minor fluctuations, while the hydrants are sources of many little rhythmic pulsations (with large variations in the period).Therefore, the contribution of hydrants to the formation of the main HF does not appear at once, but for several minutes in the interval between the incoming and outgoing flows.
Larva morphology of shore flies Ephydra riparia and Paracoenia fumosa (Diptera: Ephydridae) and adaptation of Diptera to increased salinity
Authors: Yakovleva E. Yu. , Naimark E. B. , Sivunova D. D. , Krivosheina M. G. , Markov A. V.
Published: April 2024

Larvae of many shore fly species (family Ephydridae) are adapted to living in water with high or extremely high salinity. Little is known about the morphological and physiological foundations of such adaptation. We described the details of the morphology of third-instar larvae of two shore flies: Ephydra riparia and Paracoenia fumosa and presented the scanning electron microscopy (SEM) images. For the first time, by silver-staining and SEM, we proved that the larvae of both studied species had anal organs (AO) – specialized structures that serve an osmoregulatory function and are responsible for the transport of ions from the environment to the larval hemolymph (but not in the opposite direction). We compared the larvae morphology of the studied species with some other shore fly species from the genera Ephydra, Paracoenia, Hydrellia, and Coenia, as well as with larvae of the model species Drosophila melanogaster (family Drosophilidae). Special attention was paid to the morphology of AO, which contribute to the adaptation of larvae to increased salinity. Extremely halophilic species either do not have AO, or they are poorly developed, while moderately halophilic shore flies have more developed features connected with the permeability of the AO cuticle and active ion transport. These features are most developed in freshwater shore flies. AO activity can vary due to the shape and area of the AO, the smoothness or wrinkling of the cuticle, and the presence of nanoscale pits on it. Described variability of AO structure is probably adaptive since, at high salinity, both the permeability of the AO cuticle and the active transport of ions from the environment to the hemolymph become less beneficial or even harmful.
Phylloplane as fungi habitat
Authors: Tsarelunga А. А. , Blagoveschenskaya Е. Yu.
Published: April 2024

As currently shown the phylloplane of different plants is actively colonized by yeasts and filamentous fungi of different taxonomic groups. The features of the leaf as a microhabitat are low humidity, susceptibility to mechanical effects of rain and wind, lack of nutrients on the surface, and high insolation, which causes the allocation of epiphytic fungi as a separate ecological group. Although the data vary from plant to plant, in general it can be said that basidial yeasts and such filamentous fungi as Alternaria, Epicoccum, Cladosporium, Phoma and Trichoderma are most commonly found on plant surfaces. The biological cycle of epiphytic fungi has not yet been studied, but it is assumed that it begins with the specific adhesion of the spore on the surface, followed by the formation of biofilms or the so-called “aggregates” that combine bacteria, yeast and filamentous fungi and ends with the formation of spores either on the surface of a living plant or on dead and decaying leaves.
Biginelli reaction in the synthesis of ethyl 4-(6-aryl-5-benzoyl-4-hydroxy-2-thioxohexahydropyrimidine-4-carboxamido)benzoates
Authors: Gein V. L , Zamaraeva T. M , Gorgopina E. V , Dmitriev M. V
Published: April 2024

Three-component Biginelli reaction of ethyl 4-(2,4-dioxo-4-phenylbutanamido)benzoate, aromatic aldehyde and thiourea in acetic acid in the presence of sodium acetate led to the formation of ethyl 4-(6-aryl-5-benzoyl4-hydroxy-2-thioxohexahydropyrimidine-4-carboxamido)benzoates. Structure of the obtained compounds was established by IR, 1H NMR, 13C spectroscopy methods.