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Ospennikov AS, Gavrilov AA, Artykulnyi OP, Kuklin AI, Novikov VV, Shibaev AV, Philippova OE. Transformations of wormlike surfactant micelles induced by a water-soluble monomer. J Colloid Interface Sci 2021; 602:590-601. [PMID: 34147750 DOI: 10.1016/j.jcis.2021.05.062] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/10/2021] [Accepted: 05/11/2021] [Indexed: 10/21/2022]
Abstract
HYPOTHESIS Wormlike surfactant micelles (WLMs) are prospective as nanoreactors for micellar copolymerization of hydrophilic and hydrophobic monomers. Hydrophilic monomers can destroy WLMs. Large size and cylindrical shape of micelles can be preserved by high salt content favoring closer packing of surfactant heads. EXPERIMENTS The effect of a water-soluble monomer (acrylamide) on the structure and rheological properties of giant WLMs of an anionic surfactant potassium oleate at different salt content was investigated by combined experimental (SANS, rheometry, fluorescence and NMR spectroscopy, tensiometry) and molecular dynamics simulations studies. FINDINGS At low salt content, when WLMs are linear, acrylamide induces their shortening and transformation into spherical micelles as a result of its incorporation into the micellar corona, leading to the drop of viscosity. At high salt content providing branched WLMs, monomer first triggers their transition to long linear chains, which enhances the viscoelasticity, and then to rods. This is the first report showing that the effect of monomer on the rheological properties is quite different for linear and branched micelles. Using branched micelles allows preserving large WLMs at high water-soluble monomer content, which is favorable for their use as nanoreactors for synthesis of copolymers with high degree of blockiness, which give mechanically tough polymer gels.
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Novikov VV, Kuznetsov SV, Mitroshenkov NV, Matovnikov AV, Ponkratov KV, Konoplin NA, Tolstosheev AK, Bud'ko SL. Magnetic phase transition and lattice dynamic features in ErB 2C borocarbide. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:215701. [PMID: 33592592 DOI: 10.1088/1361-648x/abe6de] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 02/16/2021] [Indexed: 06/12/2023]
Abstract
A sample of erbium borocarbide ErB2C was synthesized from a stoichiometric mixture of erbium, boron, and pyrographite hydride. Temperature dependent magnetic susceptibility, heat capacity and lattice parameters of borocarbide at 2-300 K were experimentally investigated, the Raman spectrum was determined and analyzed. Sharp anomalies in the heat capacity and magnetic properties of ErB2C nearT= 16.3 K, caused by the transition to the antiferromagnetic state, as well as diffuse anomalies at a higher temperature, caused by the effect of the crystal field (Schottky anomalies) were revealed. It was found that the magnetic phase transition does not cause measurable anomalies in the lattice parameters of borocarbide due to the weak coupling between the Er3+ion subsystem and the B-C layers. Almost zero thermal expansion of erbium borocarbide in the basal plane (alongaandbaxes) (anisotropic invar effect) as well as an unusual character of thec-axis thermal expansion were observed. The first of these features is due to the high bonding energy in the B-C layers and the weak bond between the layers in the borocarbide crystal lattice. It was found that the anomalous expansion along thecaxis is a consequence of the action of the crystal field. The splitting scheme for the ground level of Er3+ions by crystal field was determined from the analysis of the Schottky anomaly of the heat capacity.
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Rudakova DA, Volodin BY, Petrov DS, Novikov VV, Filimonov AP. [The analysis of failures of intra-familial relationships in families with children suffering of diabetes mellitus]. PROBLEMY SOTSIAL'NOI GIGIENY, ZDRAVOOKHRANENIIA I ISTORII MEDITSINY 2021; 29:437-441. [PMID: 34190472 DOI: 10.32687/0869-866x-2021-29-3-437-441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 02/11/2021] [Indexed: 06/13/2023]
Abstract
The article presents the results of study of in-family (child-parents) relationships in families with children suffering with diagnosed diabetes mellitus type I. The purpose of study is to investigate the disorders of family relationships in families of such kind. The established disorders allow to develop psychotherapeutic measures both for children and their parents. Materials and methods. The study covered 30 families with children of primary school age (7-10 years old) with diabetes mellitus. The families with children with severe concomitant diseases and broken families were excluded of the sampling. The control group consisted of 30 relevant families with healthy children. The in-family relationships were explored using a number of psychological tests applied to children and their mothers. The results. In mothers of the studied families prevailed authoritarian type of upbringing, which was expressed in tendency to hyper-protect and to over-control. The phobia of losing child and the tendency to reject it were also established. The children suffered from high level of anxiety. They had more positive attitude to mother than to father. The conclusion. The established disorders of in-family relationships in families with children with diabetes mellitus can serve as targets for psychotherapeutic activities both with children and their parents.
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Golovanov IS, Malykhin RS, Lesnikov VK, Nelyubina YV, Novikov VV, Frolov KV, Stadnichenko AI, Tretyakov EV, Ioffe SL, Sukhorukov AY. Revealing the Structure of Transition Metal Complexes of Formaldoxime. Inorg Chem 2021; 60:5523-5537. [PMID: 33826845 DOI: 10.1021/acs.inorgchem.0c03362] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Aerobic reactions of iron(III), nickel(II), and manganese(II) chlorides with formaldoxime cyclotrimer (tfoH3) and 1,4,7-triazacyclononane (tacn) produce indefinitely stable complexes of general formula [M(tacn)(tfo)]Cl. Although the formation of formaldoxime complexes has been known since the end of 19th century and applied in spectrophotometric determination of d-metals (formaldoxime method), the structure of these coordination compounds remained elusive until now. According to the X-ray analysis, [M(tacn)(tfo)]+ cation has a distorted adamantane-like structure with the metal ion being coordinated by three oxygen atoms of deprotonated tfoH3 ligand. The metal has a formal +4 oxidation state, which is atypical for organic complexes of iron and nickel. Electronic structure of [M(tacn)(tfo)]+ cations was studied by XPS, NMR, cyclic (CV) and differential pulse (DPV) voltammetries, Mössbauer spectroscopy, and DFT calculations. Unusual stabilization of high-valent metal ion by tfo3- ligand was explained by the donation of electron density from the nitrogen atom to the antibonding orbital of the metal-oxygen bond via hyperconjugation as confirmed by the NBO analysis. All complexes [M(tacn)(tfo)]Cl exhibited high catalytic activity in the aerobic dehydrogenative dimerization of p-thiocresol under ambient conditions.
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Novikov VV, Bud'ko SL, Matovnikov AV, Mitroshenkov NV, Pilipenko KS, Konoplin NA, Plokhikh IV, Pfitzner A, Shevelkov AV. The specific features of phononic and magnetic subsystems of type-VII clathrate EuNi 2P 4. Phys Chem Chem Phys 2020; 22:18025-18034. [PMID: 32756633 DOI: 10.1039/d0cp02221g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A type-VII clathrate with a Eu2+ guest embedded into a Ni-P covalent framework, EuNi2P4, was synthesized by a standard two-stage ampoule synthesis and confirmed to crystallize in the orthorhombic space group Fddd with unit cell parameters a = 5.1829(1) Å, b = 9.4765(1) Å, and c = 18.9900(1) Å. A general technique for studying the lattice and magnetic properties of REE containing compounds is proposed. The temperature and field dependences of electrical resistivity ρ(T,H), magnetization M(T,H), magnetic susceptibility χ(T,H), heat capacity Cp(T), and unit cell parameters a(T), b(T), c(T), and volume V(T) were experimentally studied and analyzed at different pressures in the temperature range of 2-300 K. A cascade of anomalies in the studied dependences was identified and attributed to the magnetic phase transformation and peculiar lattice contributions at temperatures below 20 K. As a result of comparison with an isostructural clathrate SrNi2P4, the parameters of the magnetic and lattice contributions were determined. It is characteristic that the phase transition from the paramagnetic to the magnetically ordered state is not reflected in the temperature changes of the lattice parameters due to weak bonds between guest europium atoms and the Ni-P host matrix. We have constructed a tentative H-T phase diagram based on the M(T) and M(H) data, which includes 6 different phases. It is established that the anomalous lattice contribution to the clathrate heat capacity CTLS(T) appears due to the effect of two-level systems (TLS) in the Eu2+ subsystem on the thermodynamic properties of EuNi2P4. The values of TLS parameters as well as the parameters of the magnetic subsystem of the clathrate were determined.
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Pavlov AA, Nehrkorn J, Zubkevich SV, Fedin MV, Holldack K, Schnegg A, Novikov VV. A Synergy and Struggle of EPR, Magnetometry and NMR: A Case Study of Magnetic Interaction Parameters in a Six-Coordinate Cobalt(II) Complex. Inorg Chem 2020; 59:10746-10755. [DOI: 10.1021/acs.inorgchem.0c01191] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Novikov DV, Selivanova SG, Krasnogorova NV, Gorshkova EN, Pleskova SN, Novikov VV, Karaulov AV. Serum Protein Corona Abolishes Changes in the Expression of Proinflammatory Genes Induced by Quantum Dots in Human Blood Mononuclear Cell. Bull Exp Biol Med 2020; 169:95-99. [PMID: 32495165 DOI: 10.1007/s10517-020-04832-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Indexed: 10/24/2022]
Abstract
We studied changes in the transcription of genes encoding cytokines (TNF, IL-6, IL-10, and IL-32), cell activation markers (ICAM1, CD38, Fas, and FCGRIII), ROS production catalyst (NOX2), autophagy (Beclin 1, LC3B, and p62) and apoptosis (BAX, BCL2) regulators in peripheral blood mononuclear cells upon contact with quantum dots CdSe/ZnS-MPA and CdSe/CdSeZnS/ZnS-PTVP. Up-regulation of TNF, ICAM1, Fas, p62 mRNA and down-regulation of the FCGRIII and NOX2 mRNA in response to the presence of quantum dots were revealed. The formation of serum protein corona on the surface of quantum dots abolished this effect.
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Adonin SA, Novikov AS, Chernova KV, Vinnik DA, Taskaev SV, Korolkov IV, Ilyina EV, Pavlov AA, Novikov VV, Sokolov MN, Fedin VP. Heteroleptic copper(II) complexes with 2-bromo-5-methylpyridine: Structures, features of non-covalent interactions and magnetic behavior. Inorganica Chim Acta 2020. [DOI: 10.1016/j.ica.2019.119333] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Novikov VV, Matovnikov AV, Mitroshenkov NV, Shevelkov AV, Bud'ko SL. Crystal lattice disorder and characteristic features of the low-temperature thermal properties of higher borides. Dalton Trans 2020; 49:2138-2144. [PMID: 31994559 DOI: 10.1039/c9dt04919c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Heat capacity CP(T) and lattice parameters a(T), b(T) and c(T) of LuB44Si3.5 borosilicide are experimentally studied as a function of temperature in the range of 2-300 K. The results are compared with those of pseudo-isostructural LuB50 boride. At the lowest temperatures, it is shown that the CP(T) dependence of borosilicide changes linearly with temperature. This is attributed to the effect of glass-like behaviour of the heat capacity due to the disorder in the sublattice of non-metals. The presence of defects in the B-Si sublattice and the irregular form of the cages in the B-Si matrix, which are occupied by Lu3+ ions, lead to the formation of two-level systems (TLS) in the Lu3+ subsystem. The TLS make a characteristic bell-like low-temperature contribution to the heat capacity of borosilicide. We show that there is a wide temperature range (5-150 K) of negative thermal expansion of borosilicide, which is attributed to the influence of quasi-independent vibrations of Lu3+ ions in the cages of the borosilicide crystal structure.
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Chernikova EY, Ruleva AY, Tsvetkov VB, Fedorov YV, Novikov VV, Aliyeu TM, Pavlov AA, Shepel NE, Fedorova OA. Cucurbit[7]uril-driven modulation of ligand-DNA interactions by ternary assembly. Org Biomol Chem 2020; 18:755-766. [PMID: 31912862 DOI: 10.1039/c9ob02543j] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The design of small organic molecules with a predictable and desirable DNA-binding mechanism is a topical research task for biomedicine application. Herein, we demonstrate an attractive supramolecular strategy for controlling the non-covalent ligand-DNA interaction by binding with cucurbituril as a synthetic receptor. With a combination of UV/vis, CD and NMR experiments, we demonstrate that the bis-styryl dye with two suitable binding sites can involve double stranded DNA and cucurbituril in the formation of the supramolecular triad. The ternary assembly is formed as a result of the interaction of macrocyclic cucurbituril with one pyridinium fragment of the bis-styryl dye, while the second pyridinium fragment of the dye is effectively associated with DNA backbones, which leads to a change in the ligand-DNA binding mode from aggregation to a minor groove. This exciting outcome was supported by molecular docking studies that help to understand the molecular orientation of the supramolecular triad and elucidate the destruction of dye aggregates caused by cucurbituril. These studies provide valuable information on the mechanisms of DNA binding to small molecules and recognition processes in bioorganic supramolecular assemblies constructed from multiple non-covalent interactions.
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Shein IR, Novikov VV, Kuznetsov SV, Ponkratov KV, Matovnikov AV, Mitroshenkov NV, Kornev BI, Morozov AV, Prishchep VL, Bud'ko SL. Thermodynamic properties and lattice dynamics investigation of LuB 2C: experiment and ab initio calculations. Phys Chem Chem Phys 2019; 21:24684-24694. [PMID: 31674635 DOI: 10.1039/c9cp02880c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A sample of lutetium carboboride LuB2C was synthesized from a mixture of lutetium hydride, boron and carbon by annealing in argon. The temperature dependence of the heat capacity Cp(T) (2-300 K) and lattice parameters a(T), b(T), and c(T) (5-300 K) of the carboboride was experimentally determined. The experimental values of the heat capacity were fitted with the approximation Cp(T) = aT + ΣCD + CE + CTLS(T). Here the first term is the electronic contribution, the second is the sum of the Debye components, the third is the Einstein contribution, and the fourth is the contribution to the heat capacity due to the vibrations of the two-level systems which are formed in the Lu-subsystem due to the asymmetry of the B-C atomic arrangement around the Lu3+-ions and, as a consequence, the possible transition of the lutetium atoms between spatially close, but energetically non-equivalent positions. A strong anisotropy of the thermal expansion of the carboboride was revealed. Along the c axis the coefficient of thermal expansion monotonically increases; in the basal plane, the expansion is practically not observed. The temperature dependence of the unit cell volume Vu(T) has been analyzed in the Debye-Einstein approximation taking into account the electronic contribution and effect of two-level systems. The values of the Gruneisen parameters corresponding to different modes of the phonon spectrum of the carboboride have been determined. The frequencies of the lattice vibrations, determined in a Raman scattering experiment, are in satisfactory agreement with the parameters obtained from Cp(T) using the Debye-Einstein approximation. Using ab initio band theory methods and an exchange-correlation functional in the PBE form in the VASP package, it was established that the total energies of these two crystal structures differ by no more than 0.01 eV f.u.-1. Calculations of the thermodynamic properties of LuB2C yielded similar results for orthorhombic and tetragonal phases of the carboboride.
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Pavlov AA, Aleshin DY, Nikovskiy IA, Polezhaev AV, Efimov NN, Korlyukov AA, Novikov VV, Nelyubina YV. New Spin-Crossover Complexes of Substituted 2,6-Bis(pyrazol-3-yl)pyridines. Eur J Inorg Chem 2019. [DOI: 10.1002/ejic.201900432] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Serkova ES, Chamkin AA, Boldyrev KL, Novikov VV, Peregudov AS, Shifrina ZB. Synthesis and electrochemical behaviour of rigid ferrocenyl-terminated pyridylphenylene dendrimers. POLYMER 2019. [DOI: 10.1016/j.polymer.2019.04.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Pavlov AA, Aleshin DY, Savkina SA, Belov AS, Efimov NN, Nehrkorn J, Ozerov M, Voloshin YZ, Nelyubina YV, Novikov VV. A Trigonal Prismatic Cobalt(II) Complex as a Single Molecule Magnet with a Reduced Contribution from Quantum Tunneling. Chemphyschem 2019; 20:1001-1005. [PMID: 30897255 DOI: 10.1002/cphc.201900219] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Indexed: 01/27/2023]
Abstract
Herein, we report a new trigonal prismatic cobalt(II) complex that behaves as a single molecule magnet. The obtained zero-field splitting, which is also directly accessed by THz-EPR spectroscopy (-102.5 cm-1 ), results in a large magnetization reversal barrier U of 205 cm-1 . Its effective value, however, is much lower (101 cm-1 ), even though there is practically no contribution from quantum tunneling to magnetization relaxation.
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Pavlov AA, Nehrkorn J, Pankratova YA, Ozerov M, Mikhalyova EA, Polezhaev AV, Nelyubina YV, Novikov VV. Detailed electronic structure of a high-spin cobalt(ii) complex determined from NMR and THz-EPR spectroscopy. Phys Chem Chem Phys 2019; 21:8201-8204. [DOI: 10.1039/c9cp01474h] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Here we report a combined use of THz-EPR and paramagnetic NMR spectroscopy for obtaining a detailed electronic structure of a high-spin cobalt(ii) complex.
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Belova (Savkina) SA, Dudkin SV, Belov AS, Nelyubina YV, Novikov VV, Zubavichus YV, Voloshin YZ. Pseudomacrobicyclic Phthalocyaninate-Capped Cobalt(III) tris-Pyridineoximates: Template Synthesis, X-Ray Structure and Spectral Characteristics. MACROHETEROCYCLES 2019. [DOI: 10.6060/mhc190550d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Nehrkorn J, Veber SL, Zhukas LA, Novikov VV, Nelyubina YV, Voloshin YZ, Holldack K, Stoll S, Schnegg A. Determination of Large Zero-Field Splitting in High-Spin Co(I) Clathrochelates. Inorg Chem 2018; 57:15330-15340. [PMID: 30495930 DOI: 10.1021/acs.inorgchem.8b02670] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Nikolaevskii SA, Evstifeev IS, Kiskin MA, Starikova AA, Goloveshkin AS, Novikov VV, Gogoleva NV, Sidorov AA, Eremenko IL. Coordination capabilities of metal ions and steric features of organic ligands affecting formation of mono- or binuclear zinc(II) and cadmium(II) pivalates. Polyhedron 2018. [DOI: 10.1016/j.poly.2018.06.021] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Chritinin DF, Novikov VV. [Mental disorders in patients with HIV infection: systematics and features of development]. Zh Nevrol Psikhiatr Im S S Korsakova 2018; 116:19-22. [PMID: 27240175 DOI: 10.17116/jnevro2016116519-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To identify and systematize characteristics and patterns of formation and development of mental disorders in HIV-infection. MATERIAL AND METHODS Two hundred and fifty patients with HIV-infection and 50 injection drug users, aged 18-50 years, were examined. Most of HIV-infected people were aged from 21 to 40 years. In addition to clinical and psychopathological methods, clinical laboratory instrumentation and experimental psychological method were used. RESULTS AND CONCLUSION Mental disorders in HIV-infected patients include psychogenic-reactive, exogenous organic and personality disorders. The dynamics of these disorders depends on the combined effects of somatogenic, nosogenic and premorbid personality factors.
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Novikov VV, Pilipenko KS, Matovnikov AV, Mitroshenkov NV, Likhanov MS, Tyablikov AS, Shevelkov AV. Effect of the cation sublattice composition of tin-based type-I clathrates on their low-temperature thermal properties. Dalton Trans 2018; 47:11219-11225. [PMID: 30051122 DOI: 10.1039/c8dt02306a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We performed an experimental study on thermal properties of the Sn18In6As21.5I8 clathrate by measuring temperature dependencies of its heat capacity (2-300 K) and thermal expansion (5-300 K). By comparing the results with those published previously for Sn-based clathrates Sn24P19.2I8, Sn20Zn4P20.8I8, and Sn17Zn7P22I8, we established that partial replacement of tin and phosphorus by heavier indium and arsenic, respectively, leads to lowering vibration frequencies in both host and guest substructures. Deviation of the observed thermal properties at low temperatures from those predicted by the Einstein-Debye model is caused by the Schottky-like contribution of two-level systems to heat capacity and thermal expansion. These systems form owing to transitions of guest atoms in non-spherical 24-vertex cages between stationary states with close energies.
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Pavlov A, Savkina SA, Belov AS, Voloshin YZ, Nelyubina YV, Novikov VV. Very Large Magnetic Anisotropy of Cage Cobalt(II) Complexes with a Rigid Cholesteryl Substituent from Paramagnetic NMR Spectroscopy. ACS OMEGA 2018; 3:4941-4946. [PMID: 31458710 PMCID: PMC6641741 DOI: 10.1021/acsomega.8b00772] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 04/27/2018] [Indexed: 05/05/2023]
Abstract
Variable-temperature NMR spectroscopy has recently emerged as a new alternative to the magnetometry methods for studying single molecule magnets. Its use is based on an accurate determination of magnetic susceptibility tensor anisotropy Δχ, which is not always achievable due to some contact contribution to NMR chemical shifts and possible conformational dynamics. Here, we applied this approach to cholesteryl-substituted cage cobalt(II) complexes featuring a very large magnetic anisotropy. Conformational rigidity and large size of the cholesteryl substituent with many magnetically nonequivalent nuclei resulted in an excellent convergence of experimental and calculated 1H and 13C chemical shifts, thus allowing for the determination of Δχ value for all of the synthesized cobalt(II) complexes with a very high accuracy and providing a more reliable zero-field splitting energy for further calculations.
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Voloshin YZ, Novikov VV, Nelyubina YV, Belov AS, Roitershtein DM, Savitsky A, Mokhir A, Sutter J, Miehlich ME, Meyer K. Synthesis and characterization of an Fe(i) cage complex with high stability towards strong H-acids. Chem Commun (Camb) 2018; 54:3436-3439. [DOI: 10.1039/c7cc09611a] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The new iron(i) dioximate showed an unrivaled stability towards strong acids. This calls for a reassessment of the electrocatalytic activity of similar low-valent Co and Fe cage complexes, which have shown to be effective HER electrocatalysts.
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Zelinskii GE, Belov AS, Belaya IG, Vologzhanina AV, Novikov VV, Varzatskii OA, Voloshin YZ. The molecular design of cage metal complexes for biological applications: pathways of the synthesis, and X-ray structures of a series of new N2-, S2- and O2-alicyclic iron(ii) di- and tetrachloroclathrochelates. NEW J CHEM 2018. [DOI: 10.1039/c7nj03051g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
New iron(ii) di- and tetrahalogenoclathrochelates with apical functionalizing substituents were prepared and characterized.
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Vinogradov MM, Perekalin DS, Gutsul EI, Novikov VV, Smol'yakov AF, Wadepohl H, Kudinov AR, Loginov DA. Cluster [Co
3
(CO)
3
(µ
2
‐CO)
3
(µ
3
‐C
8
H
8
)]
–
as a Ligand: Experimental and Theoretical Study. Eur J Inorg Chem 2017. [DOI: 10.1002/ejic.201701160] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Pavlov AA, Denisov GL, Kiskin MA, Nelyubina YV, Novikov VV. Probing Spin Crossover in a Solution by Paramagnetic NMR Spectroscopy. Inorg Chem 2017; 56:14759-14762. [DOI: 10.1021/acs.inorgchem.7b02649] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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