41 results on '"Ivanov AY"'
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2. Slow inhibitory postsynaptic potentials and hyperpolarization evoked by noradrenaline in the neurones of mammalian sympathetic ganglion
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Skok Vi and Ivanov Ay
- Subjects
Superior cervical ganglion ,Physiology ,Neurotransmission ,Inhibitory postsynaptic potential ,Synaptic Transmission ,Norepinephrine ,Postsynaptic potential ,medicine ,Animals ,Reversal potential ,Phentolamine ,Evoked Potentials ,Ganglia, Sympathetic ,Chemistry ,General Neuroscience ,Depolarization ,Neural Inhibition ,Hyperpolarization (biology) ,Receptors, Adrenergic, alpha ,Sympathetic ganglion ,Electric Stimulation ,body regions ,medicine.anatomical_structure ,Biophysics ,Neurology (clinical) ,Rabbits ,Neuroscience - Abstract
Slow IPSPs evoked in the neurones of rabbit isolated superior cervical ganglion by repetitive orthodromic stimulation, and a response evoked in the neurones of this ganglion by perfusion of noradrenaline, were studied using intracellular microelectrodes. Slow IPSPs were observed in 36% of neurones studied, and when investigated after treatment with D-tubocurarine and neostigmine, had a mean amplitude of 4.4 +/- 0.2 mV (mean +/- S.E.) and duration of 5 sec to 1.5 min. Two types of slow IPSPs occurring in different neurones were found. The slow IPSP of the first type was followed by a decrease in cell input resistance, was increased by depolarization and decreased by hyperpolarization of the membrane, with the reversal potential, if estimated by extrapolation method, equal to -77.8 +/- 3.3 mV. The slow IPSP of the second type was not followed by any change in cell input resistance, was increased by hyperpolarization and decreased by depolarization. The slow IPSP of the second type was reversibly blocked by phentolamine (1.4 X 10(-4) M). Noradrenaline (1 X 10(-4) M) evoked hyperpolarization or hyperpolarization followed by depolarization in 55% of the neurones studied. Hyperpolarization evoked by noradrenaline had a mean amplitude to 5.0 +/- 0.2 mV, was not followed by any change in cell input resistance, was reversibly blocked by phentolamine (1.4 X 10(-4) M), and was decreased by both depolarization and hyperpolarization of the cell membrane. It has been concluded that there are two groups of neurones in superior cervical ganglia, different with respect to the ionic mechanisms underlying the slow IPSP. In the first group of neurones the slow IPSP is probably due to an increase in potassium permeability of the membrane. The ionic mechanisms underlying the slow IPSP in the second group of neurones of noradrenaline-induced hyperpolarization remain unclear.
- Published
- 1980
3. Key role of cycloalkyne nature in alkyne-dye reagents for enhanced specificity of intracellular imaging by bioorthogonal bioconjugation.
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Vidyakina AA, Silonov SA, Govdi AI, Ivanov AY, Podolskaya EP, Balova IA, Bräse S, and Danilkina NA
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Conjugates of benzothiophene-fused azacyclononyne BT9N-NH2 with fluorescent dyes were developed to visualise azidoglycans intracellularly. The significance of the cycloalkyne core was demonstrated by comparing new reagents with DBCO- and BCN-dye conjugates. To reduce non-specificity during intracellular bioconjugation using SPAAC, less reactive BT9N-dye reagents are preferred over highly reactive DBCO- and BCN-dye conjugates.
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- 2024
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4. Diversity of trematodes from the amphibian anomaly P hotspot: Role of planorbid snails.
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Svinin AO, Chikhlyaev IV, Bashinskiy IW, Osipov VV, Neymark LA, Ivanov AY, Stoyko TG, Chernigova PI, Ibrogimova PK, Litvinchuk SN, and Ermakov OA
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- Animals, Ecosystem, Snails parasitology, Amphibians, Trematoda physiology, Trematode Infections veterinary, Trematode Infections parasitology
- Abstract
Trematode infection of the second intermediate hosts can lead to changes in their fitness and, as a result, a change in the invasion rate of animal communities. It is especially pronounced during the invasion of parasite species that reduce activity due to the manipulation of hosts through the changes of their morphology and physiology. One of these cases is an anomaly P syndrome hotspot found in some populations of water frogs and toads in Europe caused by the trematode Strigea robusta metacercariae. The occurrence of pathogen and their participation in ecosystems are intrigues questions in the anomaly P phenomenon, as well as the role of planorbid snails that serve as the first intermediate hosts for many trematode species. Herein, we focused on trematodes spectra from planorbid snails and amphibians from the anomaly P hosts with the aim to undetected interactions between the pathways of parasites. Emerging cercariae of 6802 planorbid snails of dominant species (Planorbarius corneus, Planorbis planorbis, and Anisus spp.) were detected by both morphological and molecular methods in seven waterbodies in Privolzhskaya Lesostep Nature Reserve (Russia). A total of 95 sequences of 18 species were received, and 48 sequences were unique and did not present in any genetic databases. The 18 species of trematodes from snails and 14 species of trematodes from amphibian hosts (Pelophylax ridibundus; Ranidae; Anura) were detected. Three species (Echinostoma nasincovae, Tylodelphys circibuteonis and Australapatemon burti) was new for the trematode fauna of the Middle Volga River region and Russia as a whole. Eleven species of parasitic flatworms have amphibians in their life cycles and nine species used amphibians as metacercariae hosts: Echinostoma nasincovae, E. miyagawai, Echinoparyphium recurvatum, Tylodelphys circibuteonis, Neodiplostomum spathula, Paralepoderma cloacicola, Macrodera longicollis, Strigea robusta, and Strigea strigis. The occurrence of trematode species from planorbid mollusks and frogs were compared., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Svinin et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
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- 2023
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5. Synthesis of 3-Aryl-3-(Furan-2-yl)Propanoic Acid Derivatives, and Study of Their Antimicrobial Activity.
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Kalyaev MV, Ryabukhin DS, Borisova MA, Ivanov AY, Boyarskaya IA, Borovkova KE, Nikiforova LR, Salmova JV, Ul'yanovskii NV, Kosyakov DS, and Vasilyev AV
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- Carbon, Escherichia coli, Esters pharmacology, Furans pharmacology, Microbial Sensitivity Tests, Anti-Infective Agents chemistry, Propionates
- Abstract
Reactions of 3-(furan-2-yl)propenoic acids and their esters with arenes in Brønsted superacid TfOH affords products of hydroarylation of the carbon-carbon double bond, 3-aryl-3-(furan-2-yl)propenoic acid derivatives. According to NMR and DFT studies, the corresponding O,C-diprotonated forms of the starting furan acids and esters should be reactive electrophilic species in these transformations. Starting compounds and their hydroarylation products, at a concentration of 64 µg/mL, demonstrate good antimicrobial activity against yeast-like fungi Candida albicans . Apart from that, these compounds suppress Escherichia coli and Staphylococcus aureus .
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- 2022
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6. Oil spills in the Barents Sea: The results of multiyear monitoring with synthetic aperture radar.
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Ivanov AY, Kucheiko AY, Ivonin DV, Filimonova NA, Terleeva NV, and Evtushenko NV
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- Environmental Monitoring methods, Oceans and Seas, Radar, Petroleum Pollution analysis, Water Pollutants, Chemical analysis
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This paper presents the results of multiyear satellite monitoring of oil pollution in the Barents Sea conducted in 2015-2020. Monitoring was based on synthetic aperture radar (SAR) images from the European Space Agency's Sentinel-1A and Sentinel-1B satellites. During monitoring, more than 26,000 SAR images were collected and analyzed for oil pollution in the form of oil spills. A geographic information system (GIS) and a conventional interactive technique were used to efficiently analyze a substantial number of SAR images covering the Barents Sea. Our approach employed online geoportal based on GIS technology with a large volume of additional information (oceanographic, physical-geographical, and industrial) about the marine basin, including those for offshore oil and gas infrastructure. As a result, multiyear oil spill distribution map was generated and analyzed, and the most oil-polluted regions of the sea and natural seeps were identified. The analysis focused on the general characteristics of the spatial and temporal distribution and the main sources of oil pollution of the Barents Sea. Sources of oil spills with areas ranging from 0.5 to 90 km
2 were interpreted based on data from the automatic ship identification systems used to monitor shipping and fishing. Based on the monitoring results, the general level of oil pollution in the Barents Sea is established, statistics were calculated, and risk zones identified. The most polluted marine areas are in the southern part of the sea, where maritime shipping continuous; moderate levels of pollution appear in the fishing zones in the central part of the sea. Finally, the study results show that overall oil pollution in the Barents Sea is still relatively low compared to other marginal and inland seas of Europe., (Copyright © 2022 Elsevier Ltd. All rights reserved.)- Published
- 2022
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7. Noncovalent Axial I⋅⋅⋅Pt⋅⋅⋅I Interactions in Platinum(II) Complexes Strengthen in the Excited State.
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Bulatov E, Eskelinen T, Ivanov AY, Tolstoy PM, Kalenius E, Hirva P, and Haukka M
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Coordination compounds of platinum(II) participate in various noncovalent axial interactions involving metal center. Weakly bound axial ligands can be electrophilic or nucleophilic; however, interactions with nucleophiles are compromised by electron density clashing. Consequently, simultaneous axial interaction of platinum(II) with two nucleophilic ligands is almost unprecedented. Herein, we report structural and computational study of a platinum(II) complex possessing such intramolecular noncovalent I⋅⋅⋅Pt⋅⋅⋅I interactions. Structural analysis indicates that the two iodine atoms approach the platinum(II) center in a "side-on" fashion and act as nucleophilic ligands. According to computational studies, the interactions are dispersive, weak and anti-cooperative in the ground electronic state, but strengthen substantially and become partially covalent and cooperative in the lowest excited state. Strengthening of I⋅⋅⋅Pt⋅⋅⋅I contacts in the excited state is also predicted for the sole previously reported complex with analogous axial interactions., (© 2021 The Authors. ChemPhysChem published by Wiley-VCH GmbH.)
- Published
- 2021
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8. Metal-Involving Chalcogen Bond. The Case of Platinum(II) Interaction with Se/Te-Based σ-Hole Donors.
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Rozhkov AV, Katlenok EA, Zhmykhova MV, Ivanov AY, Kuznetsov ML, Bokach NA, and Kukushkin VY
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Platinum(II) complexes exhibiting an expressed d
z -nucleophilicity of the positively charged metal centers, namely, [Pt(ppy)(acac)] ( 1 ; acacH is acetylacetone; ppyH is 2-Ph-pyridine) and [Pt(ppy)(tmhd)] ( 2 ; tmhdH is 2,2,6,6-tetramethylheptanedione-3,5), were cocrystallized with the chalcogen bond donors (4-NC2 5 F4 )2 Ch (Ch = Se, Te) to form two isostructural cocrystals 1 ·1 /2 (4-NC5 F4 )2 Ch, and 2 ·2 /3 (4-NC5 F4 )2 Se and 2 ·(4-NC5 F4 )2 Te. The X-ray data for these cocrystals and appropriate theoretical DFT calculations (PBE0-D3BJ) allowed the recognition of the metal-involving chalcogen bond, namely, Ch··· dz 2 -PtII (its energy spans from -7 to -12 kcal/mol). In 1 ·1 /2 (4-NC5 F4 )2 Ch, Ch··· dz -Pt2 II bonding is accompanied by the C··· dz 2 -PtII interaction, representing a three-center bifurcate, whereas in 2 ·(4-NC5 F4 )2 Te the chalcogen bond Te··· dz 2 -PtII is purely two-centered and is stronger than that in 1 ·1 /2 (4-NC5 F4 )2 Ch because of more efficient orbital overlap. The association of 2 with (4-NC5 F4 )2 Te and the structure of the formed adduct in CDCl3 solutions was studied by using1 H,13 C,19 F,195 Pt,125 Te NMR,19 F-1 H HOESY, and diffusion NMR methods. The195 Pt and125 Te NMR titration and the isothermal titration calorimetry results revealed a 1:1 association of 2 with (4-NC5 F4 )2 Te.- Published
- 2021
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9. Strigea robusta causes polydactyly and severe forms of Rostand's anomaly P in water frogs.
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Svinin AO, Bashinskiy IV, Litvinchuk SN, Ermakov OA, Ivanov AY, Neymark LA, Vedernikov AA, Osipov VV, Drobot GP, and Dubois A
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- Animals, Forelimb abnormalities, Forelimb parasitology, Gastropoda parasitology, Genes, Helminth, Larva growth & development, Larva parasitology, Life Cycle Stages, Pathology, Molecular, Toes abnormalities, Toes parasitology, Polydactyly parasitology, Ranidae parasitology, Trematoda genetics, Trematoda pathogenicity, Trematoda physiology
- Abstract
Background: Cases of polydactyly in natural populations of amphibians have attracted great interest from biologists. At the end of the 1940s, the French biologist Jean Rostand discovered a polymorphic syndrome in some water frog (Anura: Pelophylax) populations that included polydactyly and some severe morphological anomalies (he called it 'anomaly P'). The cause of this anomaly remains unknown for 70 years. In a previous study, we obtained anomaly P in the laboratory in tadpoles of water frogs that developed together with molluscs Planorbarius corneus (Mollusca: Gastropoda) collected in the field. We thus proposed the 'trematode hypothesis', according to which the infectious agent responsible for anomaly P is a trematode species., Methods: Metacercariae from tadpoles with anomaly P were identified using ITS2 gene sequencing as Strigea robusta (Trematoda: Strigeidae). To verify teratogenic features of the species, cercariae of S. robusta were tested for the possibility to cause anomalies. Identification of cercariae species was made using morphological and molecular methods (sequencing of ITS2 and 28S rRNA). The tadpoles were exposed to parasites at four doses of cercariae (control, low, medium and high) and divided into two groups: "early" (at 25-27 Gosner stages) and "late" (at 29-34 Gosner stages) exposure., Results: A total of 58 (72.5%) tadpoles survived until metamorphosis under the dose-dependent experiment with the trematode S. robusta. Differences in the survival rates were observed between the exposed and unexposed tadpoles both in the group of "early" tadpoles and "late" tadpoles. The exposure of tadpoles to the cercariae of S. robusta induced anomaly P in 82% of surviving tadpoles. The severe forms developed only in "early" stages under all doses of cercariae exposure. Polydactyly predominantly developed in the "late" stages; under a light exposure dose, polydactyly also developed in "early" tadpoles. Laboratory-hatched tadpoles reared together with infected snails had different rates of survival and complexity of deformations associated with the period of coexistence., Conclusions: The experiments with direct cercariae exposure provide compelling evidence that S. robusta leads to anomaly P in tadpoles of water frogs. The manifestation of anomaly P turned out to be dependent on the stage of development, cercariae dose, and the location of the cysts.
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- 2020
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10. Arene-Ruthenium(II) Complexes Containing 11 H -Indeno[1,2- b ]quinoxalin-11-one Derivatives and Tryptanthrin-6-oxime: Synthesis, Characterization, Cytotoxicity, and Catalytic Transfer Hydrogenation of Aryl Ketones.
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Matveevskaya VV, Pavlov DI, Sukhikh TS, Gushchin AL, Ivanov AY, Tennikova TB, Sharoyko VV, Baykov SV, Benassi E, and Potapov AS
- Abstract
A series of novel mono- and binuclear arene-ruthenium(II) complexes [( p -cym)Ru(L)Cl] containing 11 H -indeno[1,2- b ]quinoxalin-11-one derivatives or tryptanthrin-6-oxime were synthesized and characterized by X-ray crystallography, IR, NMR spectroscopy, cyclic voltammetry, and elemental analysis. Theoretical calculations invoking singlet state geometry optimization, solvation effects, and noncovalent interactions were done using density functional theory (DFT). DFT calculations were also applied to evaluate the electronic properties, and time-dependent DFT was applied to clarify experimental UV-vis results. Cytotoxicity for cancerous and noncancerous human cell lines was evaluated with cell viability MTT assay. Complexes demonstrated a moderate cytotoxic effect toward cancerous human cell line PANC-1. The catalytic activity of the complexes was evaluated in transfer hydrogenation of aryl ketones. All complexes exhibited good catalytic activity and functional group tolerance., Competing Interests: The authors declare no competing financial interest., (Copyright © 2020 American Chemical Society.)
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- 2020
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11. Reactions of 2-carbonyl- and 2-hydroxy(or methoxy)alkyl-substituted benzimidazoles with arenes in the superacid CF 3 SO 3 H. NMR and DFT studies of dicationic electrophilic species.
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Ryabukhin DS, Turdakov AN, Soldatova NS, Kompanets MO, Ivanov AY, Boyarskaya IA, and Vasilyev AV
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Reactions of 2-carbonyl- and 2-hydroxy(or methoxy)alkylbenzimidazoles with arenes in the Brønsted superacid TfOH resulted in the formation of the corresponding Friedel-Crafts reaction products, 2-diarylmethyl and 2-arylmethyl-substituted benzimidazoles, in yields up to 90%. The reaction intermediates, protonated species derived from starting benzimidazoles in TfOH, were thoroughly studied by means of NMR and DFT calculations and plausible reaction mechanisms are discussed.
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- 2019
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12. Different reactivity of phosphorylallenes under the action of Brønsted or Lewis acids: a crucial role of involvement of the P=O group in intra- or intermolecular interactions at the formation of cationic intermediates.
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Lozovskiy SV, Ivanov AY, and Vasilyev AV
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3-Methylbuta-1,2-dien-1-ylphosphonic acid derivatives (phosphorylallenes) [X
2 (O=)P-CR=C=CMe2 , X = Cl, OMe, NR2 , or SAr] undergo intramolecular cyclization into the corresponding 1,2-oxaphospholium ions in the Brønsted superacid TfOH. These cations have been thoroughly studied by means of NMR spectroscopy. The hydrolysis of superacidic solutions of these species afforded cyclic phosphonic acids and other phosphorus-containing compounds. Contrary to Brønsted acids, 3-methylbuta-1,2-dien-1-ylphosphonic dichloride [Cl2 (O=)P-HC=C=CMe2 ] reacted with the Lewis acid AlCl3 in an intermolecular way forming noncyclic intermediates, which were investigated by NMR spectroscopy and DFT calculations. Hydrolysis of these species resulted in the formation of phosphoryl-substituted allyl alcohols and 1,3-butadienes. A strong coordination of the oxygen of the P=O group with AlCl3 prevented the formation of cyclic 1,2-oxaphospholium ions and played a crucial role in the different reactivity of such phosphorylallenes under the action of Brønsted or Lewis acids. Apart from that, the reaction of dichlorophosphorylallenes with arenes and AlCl3 led to products of hydroarylation of the allene system, phosphoryl-substituted alkenes and/or indanes. This is the first example of a Lewis acid-promoted intermolecular hydroarylation of allenes bearing electron-withdrawing substituents. Plausible reaction mechanisms have been proposed on the basis of the investigated reactions, and NMR analysis and DFT studies of the intermediate cationic species.- Published
- 2019
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13. Generation of 1,2-oxathiolium ions from (arysulfonyl)- and (arylsulfinyl)allenes in Brønsted acids. NMR and DFT study of these cations and their reactions.
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Lozovskiy SV, Ivanov AY, Khoroshilova OV, and Vasilyev AV
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In strong Brønsted acids (CF
3 SO3 H, FSO3 H, D2 SO4 ), (arysulfonyl)allenes (ArSO2 -CR1 =C=CR2 R3 ) and (arylsulfinyl)allenes (ArSO-CR1 =C=CR2 R3 ) undergo cyclization into the corresponding stable 1,2-oxathiolium ions, which were studied by means of NMR and DFT calculations. Quenching of solutions of these cations with low nucleophilic media, aqueous HCl, leads to their deprotonation with a stereoselective formation of (arysulfonyl)butadienes (for instance, ArSO2 -CR1 =C-C(Me)=CH2 , for R2 = R3 = Me, yields of 87-98%). Reactions of (arysulfonyl)allenes in the system TfOH (0.1 equiv)-HFIP (hexafluoropropan-2-ol) followed by hydrolysis give rise to allyl alcohols (ArSO2 -CR1 =CH-C(OH)R2 R3 , yields of 78-99%). Reflux of solutions of (arysulfonyl)allenes in the presence of TfOH (1 equiv) in 1,2-dichlorobenzene leads to the cyclization into thiochromene 1,1-dioxides in high yields. Under the action of TfOH or AlX3 (X = Cl, Br) followed by hydrolysis of reaction mixtures, (arylsulfinyl)allenes give allyl alcohols (ArSO2 -CR1 =CH-C(OH)R2 R3 ). Plausible reaction mechanisms have been proposed for all studied reactions.- Published
- 2018
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14. Dramatically Enhanced Solubility of Halide-Containing Organometallic Species in Diiodomethane: The Role of Solvent⋅⋅⋅Complex Halogen Bonding.
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Kinzhalov MA, Kashina MV, Mikherdov AS, Mozheeva EA, Novikov AS, Smirnov AS, Ivanov DM, Kryukova MA, Ivanov AY, Smirnov SN, Kukushkin VY, and Luzyanin KV
- Abstract
In the current study, we evaluated the solubility of a number of organometallic species and showed that it is noticeably improved in diiodomethane when compared to other haloalkane solvents. The better solvation properties of CH
2 I2 were associated with the substantially better σ-hole-donating ability of this solvent, which results in the formation of uniquely strong solvent-(metal complex) halogen bonding. The strength of the halogen bonding is attenuated by the introduction of additional halogen atoms in the organometallic species owing to the competitive formation of more favourable intermolecular complex-complex halogen bonding. The exceptional solvation properties of diiodomethane and its inertness towards organometallic species make this solvent a good candidate for NMR studies, in particular, for the acquisition of spectra of insensitive spins., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)- Published
- 2018
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15. Reactions of 3,3,3-Trihalogeno-1-nitropropenes with Arenes in the Superacid CF 3 SO 3 H: Synthesis of ( Z)-3,3,3-Trihalogeno-1,2-diarylpropan-1-one Oximes and Study on the Reaction Mechanism.
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Golushko AA, Sandzhieva MA, Ivanov AY, Boyarskaya IA, Khoroshilova OV, Barkov AY, and Vasilyev AV
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3,3,3-Trihalogeno-1-nitropropenes C(Hal
3 )CH═CH(NO2 ) (Hal = F, Cl, Br) in reaction with arenes in the superacid CF3 SO3 H (TfOH) at room temperature in 1 h afford 3,3,3-trihalogeno-1,2-diarylpropan-1-one oximes C(Hal3 )CH(Ar)-C(Ar)═NOH (CHal3 -oximes) in yields of 23-99%. Such CHal3 -oximes having one ortho-substituent in the aryl ring exist as atropoisomers in solutions at room temperature. Several cationic intermediates of this reaction were studied by means of NMR and DFT calculations, which proves the detailed reaction mechanism of the formation of CHal3 -oximes in TfOH. CHal3 -oximes (for Hal = Cl, Br) with DBU in DMF at microwave or thermal activation are cyclized into 5-halogeno-3,4-diarylisoxazoles in yields of 37-59%. CHal3 -oximes under the conditions of Beckmann rearrangement with PCl5 in benzene at room temperature in 24 h are turned at first into imidoyl chlorides (yields of 94-96%), which undergo transformation into the corresponding benzamides PhCONHCHPh(CHal3 ) on silica gel (yields of 46-47%).- Published
- 2018
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16. Halides Held by Bifurcated Chalcogen-Hydrogen Bonds. Effect of μ (S,N-H) Cl Contacts on Dimerization of Cl(carbene)Pd II Species.
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Mikherdov AS, Novikov AS, Kinzhalov MA, Boyarskiy VP, Starova GL, Ivanov AY, and Kukushkin VY
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The reaction of cis-[PdCl
2 (CNCy)2 ] (1) with thiazol-2-amines (2-10) leads to the C,N-chelated diaminocarbene-like complexes [PdCl{ C(N(H)4,5-R2 -thiazol-2-yl)NHCy}(CNCy)] (11-14; 82-91%) in the case of 4,5-R2 -thiazol-2-amines (R, R = H, H (2), Me, Me (3), -(CH2 )4 - (4)) and benzothiazol-2-amine (5) or gives the diaminocarbene species cis-[PdCl2 {C(N(H)Cy)N(H)4-R-thiazol-2-yl}(CNCy)] (15-19; 73-93%) for the reaction with 4-aryl-substituted thiazol-2-amines (R = Ph (6), 4-MeC6 H4 (7), 4-FC6 H4 (8), 4-ClC6 H4 (9), 3,4-F2 C6 H3 (10)). Inspection of the single-crystal X-ray diffraction data for 15-17 and 19 suggests that the structures of all these species exhibit previously unrecognized bifurcated chalcogen-hydrogen bonding μ(S,N-H) Cl and also PdII ···PdII metallophilic interactions. These noncovalent interactions collectively connect two symmetrically located molecules of 15-17 and 19, resulting in their solid-state dimerization. The existence of the μ(S,N-H) Cl system and its strength (6-9 kcal/mol) were additionally verified/estimated by a Hirshfeld surface analysis and DFT calculations combined with a topological analysis of the electron density distribution within the formalism of Bader's theory (AIM method) and NBO analysis. The observed noncovalent interactions are jointly responsible for the dimerization of 15-19 not only in the solid phase but also in CHCl3 solutions, as predicted theoretically by DFT calculations and confirmed experimentally by FTIR, HRESI-MS,1 H NMR, and diffusion coefficient NMR measurements. Available CCDC data were processed under the new moiety angle, and the observed μ(S,E-H) Cl systems were classified accordingly to E (E = N, O, C) type atoms.- Published
- 2018
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17. Fe(II)-Catalyzed Isomerization of 5-Chloroisoxazoles to 2 H-Azirine-2-carbonyl Chlorides as a Key Stage in the Synthesis of Pyrazole-Nitrogen Heterocycle Dyads.
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Mikhailov KI, Galenko EE, Galenko AV, Novikov MS, Ivanov AY, Starova GL, and Khlebnikov AF
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2-(1 H-Pyrazol-1-ylcarbonyl)-2 H-azirines were synthesized by in situ trapping of 2 H-azirine-2-carbonyl chlorides, generated by Fe(II)-catalyzed isomerization of 5-chloroisoxazoles, with pyrazoles. According to DFT calculations, the selectivity of nucleophilic substitution at the carbonyl group of 2 H-azirine-2-carbonyl chloride by a pyrazole nucleophile, which is a mixture of two tautomers, is controlled by thermodynamic factors. 2-(1 H-Pyrazol-1-ylcarbonyl)-2 H-azirines are excellent precursors for the preparation of two other pyrazole-nitrogen heterocycle dyads: 5-(1 H-pyrazol-1-yl)oxazoles by photolysis and 1-(1 H-pyrrol-2-ylcarbonyl)-1 H-pyrazoles by a Ni(II)-catalyzed reaction with 1,3-dicarbonyl compounds. 5-(1 H-Pyrazol-1-yl)oxazoles show strong emission in acetonitrile at 360-410 nm with high quantum yields.
- Published
- 2018
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18. [Surgical treatment of large and giant vertebrobasilar aneurysms manifested by brainstem compression symptoms].
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Goroshchenko SA, Petrov AE, Rozhchenko LV, Blagorazumova GP, Vyazgina EM, and Ivanov AY
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- Basilar Artery diagnostic imaging, Female, Glasgow Outcome Scale, Humans, Intracranial Aneurysm diagnostic imaging, Magnetic Resonance Imaging, Male, Middle Aged, Stents, Treatment Outcome, Vertebral Artery diagnostic imaging, Basilar Artery surgery, Brain Stem diagnostic imaging, Endovascular Procedures methods, Intracranial Aneurysm surgery, Vertebral Artery surgery
- Abstract
The study aim was to analyze the results of surgical treatment of vertebrobasilar (VB) aneurysms manifested by brainstem compression symptoms., Material and Methods: The study included 8 patients operated on in the period between 2014 and 2017. All patients underwent intravascular intervention; two patients had open surgery at the second stage., Results and Conclusion: Intravascular intervention, both alone and in combination with open surgery, is effective treatment of VB aneurysms whose clinical picture is manifested by brainstem compression symptoms. The use of flow-diverting stents in most cases has provided good radicalness in the long-term period, without worsening the functional outcome. Treatment of fusiform aneurysms of the basilar artery trunk requires separate consideration and an individual approach due to a high risk of thrombosis of short branches feeding the brainstem.
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- 2018
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19. A new family of clusters containing a silver-centered tetracapped [Ag@Ag 4 (μ 3 -P) 4 ] tetrahedron, inscribed within a N 12 icosahedron.
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Artem'ev AV, Bagryanskaya IY, Doronina EP, Tolstoy PM, Gushchin AL, Rakhmanova MI, Ivanov AY, and Suturina AO
- Abstract
An unprecedented silver-centered P-tetracapped [Ag@Ag
4 (μ3 -P)4 ] tetrahedron inscribed within a N12 icosahedral cage has been discovered in the novel family of luminescent clusters. The latter are easily self-assembled by reacting AgI salts with tris(2-pyridyl)phosphine (Py3 P).- Published
- 2017
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20. Infrared Spectrometer for ExoMars: A Mast-Mounted Instrument for the Rover.
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Korablev OI, Dobrolensky Y, Evdokimova N, Fedorova AA, Kuzmin RO, Mantsevich SN, Cloutis EA, Carter J, Poulet F, Flahaut J, Griffiths A, Gunn M, Schmitz N, Martín-Torres J, Zorzano MP, Rodionov DS, Vago JL, Stepanov AV, Titov AY, Vyazovetsky NA, Trokhimovskiy AY, Sapgir AG, Kalinnikov YK, Ivanov YS, Shapkin AA, and Ivanov AY
- Abstract
ISEM (Infrared Spectrometer for ExoMars) is a pencil-beam infrared spectrometer that will measure reflected solar radiation in the near infrared range for context assessment of the surface mineralogy in the vicinity of the ExoMars rover. The instrument will be accommodated on the mast of the rover and will be operated together with the panoramic camera (PanCam), high-resolution camera (HRC). ISEM will study the mineralogical and petrographic composition of the martian surface in the vicinity of the rover, and in combination with the other remote sensing instruments, it will aid in the selection of potential targets for close-up investigations and drilling sites. Of particular scientific interest are water-bearing minerals, such as phyllosilicates, sulfates, carbonates, and minerals indicative of astrobiological potential, such as borates, nitrates, and ammonium-bearing minerals. The instrument has an ∼1° field of view and covers the spectral range between 1.15 and 3.30 μm with a spectral resolution varying from 3.3 nm at 1.15 μm to 28 nm at 3.30 μm. The ISEM optical head is mounted on the mast, and its electronics box is located inside the rover's body. The spectrometer uses an acousto-optic tunable filter and a Peltier-cooled InAs detector. The mass of ISEM is 1.74 kg, including the electronics and harness. The science objectives of the experiment, the instrument design, and operational scenarios are described. Key Words: ExoMars-ISEM-Mars-Surface-Mineralogy-Spectroscopy-AOTF-Infrared. Astrobiology 17, 542-564.
- Published
- 2017
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21. Metal-free hydroarylation of the side chain carbon-carbon double bond of 5-(2-arylethenyl)-3-aryl-1,2,4-oxadiazoles in triflic acid.
- Author
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Zalivatskaya AS, Ryabukhin DS, Tarasenko MV, Ivanov AY, Boyarskaya IA, Grinenko EV, Osetrova LV, Kofanov ER, and Vasilyev AV
- Abstract
The metal-free reaction of 5-(2-arylethenyl)-3-aryl-1,2,4-oxadiazoles with arenes in neat triflic acid (TfOH, CF
3 SO3 H), both under thermal and microwave conditions, leads to 5-(2,2-diarylethyl)-3-aryl-1,2,4-oxadiazoles. The products are formed through the regioselective hydroarylation of the side chain carbon-carbon double bond of the starting oxadiazoles in yields up to 97%. According to NMR data and DFT calculations, N4 ,C-diprotonated forms of oxadiazoles are the electrophilic intermediates in this reaction.- Published
- 2017
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22. Thiazol-4-one derivatives from the reaction of monosubstituted thioureas with maleimides: structures and factors determining the selectivity and tautomeric equilibrium in solution.
- Author
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Pankova AS, Golubev PR, Khlebnikov AF, Ivanov AY, and Kuznetsov MA
- Abstract
2-(Alkyl(aryl)amino)thiazol-4(5 H )-ones can regioselectively be prepared from monoalkyl(aryl)thioureas and maleimides. In solution, the former heterocycles exist in a tautomeric equilibrium with 2-(alkyl(aryl)imino)thiazolidin-4-ones and the substituent on the exocyclic nitrogen atom governs the ratio of these tautomers. Isomers with the alkyl group in the endocyclic position can be obtained from N -methyl(ethyl)thioureas. 2D NMR spectroscopy and DFT calculations rationalize experimental results.
- Published
- 2016
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23. Synthesis, Transformations of Pyrrole- and 1,2,4-Triazole-Containing Ensembles, and Generation of Pyrrole-Substituted Triazole NHC.
- Author
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Funt LD, Tomashenko OA, Khlebnikov AF, Novikov MS, and Ivanov AY
- Abstract
Unprecedented pyrrole- and 1,2,4-triazole-containing ensembles, substituted 1-(1H-pyrrol-3-yl)-4H-1,2,4-triazol-1-ium bromides and 4-(1H-pyrrol-3-yl)-1H-1,2,4-triazol-4-ium bromides, were prepared from 2H-azirines and triazolium phenacyl bromides using a simple procedure. N-(1H-Pyrrol-3-yl)-N'-benzyltriazolium bromides undergo reductive debenzylation on Pd/C to give substituted 1-(1H-pyrrol-3-yl)-4H-1,2,4-triazoles and 4-(1H-pyrrol-3-yl)-1H-1,2,4-triazoles in high yields. Betaines (triazoliumylpyrrolides) and pyrrolyltriazole NHCs, which are possible products of dehydrobromination of pyrrolyltriazolium salts, have comparable thermodynamic stabilities in nonpolar solvents according to calculations at the DFT B3LYP/6-31G(d) level. The carbene forms can be easily trapped by the reaction of salts with base in the presence of sulfur. The corresponding 1- and 4-(1H-pyrrol-3-yl)-1H-1,2,4-triazole-5(4H)-thiones are formed in high yields. In the absence of sulfur as a trap, the opening of the triazole ring occurs with the formation of derivatives of N-cyanoformimidamide. According to the DFT calculations the latter is most probably formed via a pyrrolyltriazoliumide intermediate, which is the minor component of the equilibrium triazoliumylpyrrolide-pyrrolyltriazole NHC-pyrrolyltriazoliumide. Blocking of the pyrrolyltriazoliumide intermediate formation, by introduction of a substituent at the 3-position of the triazole ring, made it possible to generate the first pyrrole-substituted triazole NHC.
- Published
- 2016
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24. Friedel-Crafts Alkylation of Arenes with 2-Halogeno-2-CF3-styrenes under Superacidic Conditions. Access to Trifluoromethylated Ethanes and Ethenes.
- Author
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Sandzhieva MA, Kazakova AN, Boyarskaya IA, Ivanov AY, Nenajdenko VG, and Vasilyev AV
- Abstract
The formation of the corresponding benzyl cations [ArHC(+)-CH(X)CF3] takes place under protonation of E-/Z-2-halogeno-2-CF3 styrenes [ArCH═C(X)CF3, X = F, Cl, Br] in superacids. The structures of these new electrophiles were studied by means of NMR and theoretical DFT calculations. According to these data, in the case of bromo derivatives, the formed cations, most probably, exist as cyclic bromonium ions; however, in the cases of chloro and fluoro derivatives, open forms are more preferable. Subsequent reaction of these benzyl cations with arenes proceeds as Friedel-Crafts alkylation to afford 1,1-diaryl-2-halo-3,3,3-trifluoropropanes [Ar(Ar')CH-CH(X)CF3] in high yields (up to 96%) as a mixture of two diastereomers. The prepared halogenopropanes were easily converted into the corresponding mixtures of E-/Z-trifluoromethylated diarylethenes [Ar(Ar')C═CCF3] (in yields up to 96%) by dehydrohalogenation with base (KOH or t-BuOK). The mechanism of elimination (E2 and Ecb) depends on the nature of the leaving group and reaction conditions.
- Published
- 2016
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25. Solid-State and Solution Metallophilic Aggregation of a Cationic [Pt(NCN)L](+) Cyclometalated Complex.
- Author
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Sivchik VV, Grachova EV, Melnikov AS, Smirnov SN, Ivanov AY, Hirva P, Tunik SP, and Koshevoy IO
- Abstract
The noncovalent intermolecular interactions (π-π stacking, metallophilic bonding) of the cyclometalated complexes [Pt(NCN)L](+)X(-) (NCN = dipyridylbenzene, L = pyridine (1), acetonitrile (2)) are determined by the steric properties of the ancillary ligands L in the solid state and in solution, while the nature of the counterion X(-) (X(-) = PF6(-), ClO4(-), CF3SO3(-)) affects the molecular arrangement of 2·X in the crystal medium. According to the variable-temperature X-ray diffraction measurements, the extensive Pt···Pt interactions and π-stacking in 2·X are significantly temperature-dependent. The variable concentration (1)H and diffusion coefficients NMR measurements reveal that 2·X exists in the monomeric form in dilute solutions at 298 K, while upon increase in concentration [Pt(NCN)(NCMe)](+) cations undergo the formation of the ground-state oligomeric aggregates with an average aggregation number of ∼3. The photoluminescent characteristics of 1 and 2·X are largely determined by the intermolecular aggregation. For the discrete molecules the emission properties are assigned to metal perturbed IL charge transfer mixed with some MLCT contribution. In the case of oligomers 2·X the luminescence is significantly red-shifted with respect to 1 and originates mainly from the (3)MMLCT excited states. The emission energies depend on the structural arrangement in the crystal and on the complex concentration in solution, variation of which allows for the modulation of the emission color from greenish to deep red. In the solid state the lability of the ligands L leads to vapor-induced reversible transformation 1 ↔ 2 that is accompanied by the molecular reorganization and, consequently, dramatic change of the photophysical properties. Time-dependent density functional theory calculations adequately support the models proposed for the rationalization of the experimental observations.
- Published
- 2016
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26. Transformations of Conjugated Enynones in the Superacid CF3SO3H. Synthesis of Butadienyl Triflates, Indanones, and Indenes.
- Author
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Saulnier S, Golovanov AA, Ivanov AY, Boyarskaya IA, and Vasilyev AV
- Abstract
Conjugated 1,5-diarylpent-2-en-4-yn-1-ones add the superacid CF3SO3H to the acetylenic bond with formation of the corresponding butadienyl triflates. Under superacidic reaction conditions, these triflates are transformed into indanone or indene derivatives depending on which substituents on the aromatic ring are conjugated with the butadiene fragment. In a less acidic system (10% vol pyridine in CF3SO3H) only the formation of butadienyl triflates takes place. Cationic reaction intermediates were studied by means of NMR and DFT calculations.
- Published
- 2016
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27. [Extrapontine myelinolysis developed after aneurysmal subarachnoid hemorrhage (a case report and literature review)].
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Goroshchenko SA, Ivanov AY, Rozhchenko LV, Ivanova NE, Zabrodskaya YM, Razmologova OY, Kondrat'ev AN, Potemkina EG, Dmitrievskaya AY, Blagorazumova GP, Radzhabov SD, Petrov AE, Ivanov AA, Sinitsyn PS, and Bobinov VV
- Subjects
- Female, Humans, Intracranial Aneurysm complications, Middle Aged, Myelinolysis, Central Pontine diagnostic imaging, Myelinolysis, Central Pontine etiology, Subarachnoid Hemorrhage complications, Subarachnoid Hemorrhage etiology, Intracranial Aneurysm diagnosis, Myelinolysis, Central Pontine pathology, Subarachnoid Hemorrhage diagnosis
- Abstract
Topicality: Central pontine and extrapontine myelinolysis is a rare and dangerous form of the demyelinating process of undefined origin, the development of which is associated with a very low sodium level in the blood (hypernatremia)., Objective: To describe a rare case of extrapontine myelinolysis as a complication occurring in the hemorrhagic period of anterior communicating artery aneurysm rupture as well as to demonstrate that this condition can be diagnosed intravitally., Conclusion: Clinical vigilance of extrapontine myelinolysis may promote the timely diagnosis and treatment of this disease, which is a potential cause of death. Pulse-therapy with glucocorticoids provides the opportunity to achieve regression of neurological symptoms and to stabilize the patient's condition.
- Published
- 2016
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28. Reactions of CF3-enones with arenes under superelectrophilic activation: a pathway to trans-1,3-diaryl-1-CF3-indanes, new cannabinoid receptor ligands.
- Author
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Iakovenko RO, Kazakova AN, Muzalevskiy VM, Ivanov AY, Boyarskaya IA, Chicca A, Petrucci V, Gertsch J, Krasavin M, Starova GL, Zolotarev AA, Avdontceva MS, Nenajdenko VG, and Vasilyev AV
- Subjects
- Acids chemistry, Benzene chemistry, Carbon-13 Magnetic Resonance Spectroscopy, Crystallography, X-Ray, Endocannabinoids chemistry, Ligands, Models, Molecular, Molecular Conformation, Proton Magnetic Resonance Spectroscopy, Protons, Quantum Theory, Electrons, Indans chemical synthesis, Indans chemistry, Macrocyclic Compounds chemistry, Receptors, Cannabinoid metabolism
- Abstract
4-Aryl-1,1,1-trifluorobut-3-en-2-ones ArCH[double bond, length as m-dash]CHCOCF3 (CF3-enones) react with arenes in excess of Brønsted superacids (TfOH, FSO3H) to give, stereoselectively, trans-1,3-diaryl-1-trifluoromethyl indanes in 35-85% yields. The reaction intermediates, the O-protonated ArCH[double bond, length as m-dash]CHC(OH(+))CF3 and the O,C-diprotonated ArHC(+)CH2C(OH(+))CF3 species, have been studied by means of (1)H, (13)C, (19)F NMR, and DFT calculations. Both types of the cations may participate in the reaction, depending on their electrophilicity and electron-donating properties of the arenes. The formation of CF3-indanes is a result of cascade reaction of protonated CF3-enones to form chemo-, regio- and stereoselectively three new C-C bonds. The obtained trans-1,3-diaryl-1-trifluoromethyl indanes were investigated as potential ligands for cannabinoid receptors CB1 and CB2 types. The most potent compound showed sub-micromolar affinity for both receptor subtypes with a 6-fold selectivity toward the CB2 receptor with no appreciable cytotoxicity toward SHSY5Y cells.
- Published
- 2015
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29. Wide-aperture TeO₂ AOTF at low temperatures: operation and survival.
- Author
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Mantsevich SN, Korablev OI, Kalinnikov YK, Ivanov AY, and Kiselev AV
- Abstract
The effect of temperature on the performance in a wide-angle paratellurite acousto-optic tunable filter (AOTF) is analyzed on the example of two different AOTF configurations. The present study is a by-product of the AOTF characterization for space-borne applications. The two AOTFs serve as dispersion elements in spectrometers for Moon and Mars space missions. The operation of the AO filters was tested in the range of -50° to+40°C; we have also demonstrated the survival of an AOTF device at -130°C. The phase matching ultrasound frequency varies with temperature within 2.5×10(-5) K(-1) and 6.6×10(-5) K(-1). We link this temperature shift to elastic characteristics of the TeO2, and demonstrate that it is mostly explained by the temperature modification of the slow acoustic wave velocity. We point out the best reference describing experimental results (Silvestrova et al., 1987). A generalization is made for all wide-angle acousto-optic tunable filters based on tellurium dioxide crystal., (Copyright © 2015 Elsevier B.V. All rights reserved.)
- Published
- 2015
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30. [Effect of a vascular event on drug regimen compliance in patients with coronary atherosclerosis].
- Author
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Bunova SS, Usacheva EV, and Ivanov AY
- Subjects
- Female, Humans, Male, Middle Aged, Myocardial Infarction drug therapy, Myocardial Infarction etiology, Myocardial Infarction psychology, Needs Assessment, Percutaneous Coronary Intervention methods, Percutaneous Coronary Intervention psychology, Russia, Secondary Prevention methods, Surveys and Questionnaires, Cardiovascular Agents therapeutic use, Coronary Artery Disease drug therapy, Coronary Artery Disease etiology, Coronary Artery Disease psychology, Hypertension complications, Hypertension drug therapy, Hypertension psychology, Patient Compliance psychology, Platelet Aggregation Inhibitors therapeutic use
- Abstract
In order to assess the effect of a vascular event on adherence to treatment we examined a total of 68 patients presenting with coronary atherosclerosis. The patients' age varied from 31 to 84 years (mean 57.1±8.7). There were 55 (81.1%) men and 13 (18.9%) women. Drug regimen compliance was evaluated by means of the Morisky-Green Medication Adherence Questionnaire before and after the vascular event. Of the 68 examined patients, 15 (22.1%) had not taken any therapeutic agents before the vascular event occurred, despite existing arterial hypertension. Drug regimen compliance prior to the vascular event was low in 82.4% of cases. The number of patients with coronary atherosclerosis and low compliance to treatment before the vascular event decreased significantly thereafter (p=0.0012). After the vascular event, the number of patients adhering to the doctor's recommendations on medicamentous therapy increases considerably. At the same time, a sufficiently great number of patients [about 30% of patients after endured myocardial infarction (MI) and 18% after transcutaneous coronary intervention (TCI)] still remain in the category of those "having low drug regimen compliance" and, accordingly, have high risk for the development of recurrent vascular events. Endured TCI increases patient compliance more significantly than MI, which requires additional study of a psychological component of the given fact.
- Published
- 2015
31. Technetium and rhenium pentacarbonyl complexes with C₂ and C₁₁ ω-isocyanocarboxylic acid esters.
- Author
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Miroslavov AE, Polotskii YS, Gurzhiy VV, Ivanov AY, Lumpov AA, Tyupina MY, Sidorenko GV, Tolstoy PM, Maltsev DA, and Suglobov DN
- Subjects
- Carboxylic Acids chemistry, Esters chemistry, Magnetic Resonance Spectroscopy, Spectrophotometry, Infrared, X-Ray Diffraction, Organometallic Compounds chemical synthesis, Organotechnetium Compounds chemical synthesis, Rhenium chemistry, Technetium chemistry
- Abstract
Technetium(I) and rhenium(I) pentacarbonyl complexes with ethyl 2-isocyanoacetate and methyl 11-isocyanoundecanoate, [M(CO)5(CNCH2COOEt)]ClO4 (M = Tc (1) and Re (2)) and [M(CO)5(CN(CH2)10COOMe)]ClO4 (M = Tc (3) and Re (4)), were prepared and characterized by IR, (1)H NMR, and (13)C{(1)H} NMR spectroscopy. The crystal structures of 1 and 2 were determined using single-crystal X-ray diffraction. The kinetics of thermal decarbonylation of technetium complexes 1 and 3 in ethylene glycol was studied by IR spectroscopy. The rate constants and activation parameters of this reaction were determined and compared with those for [Tc(CO)6](+). It was found that rhenium complexes 2 and 4 were stable with respect to thermal decarbonylation. Histidine challenge reaction of complexes 1 and 2 in phosphate buffer was examined by IR spectroscopy. In the presence of histidine, the rhenium pentacarbonyl isocyanide complex partially decomposes to form an unidentified yellow precipitate. Technetium analogue 1 is more stable under these conditions.
- Published
- 2014
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32. Evidence of active regulation of cerebral venous tone in individuals undergoing embolization of brain arteriovenous malformations.
- Author
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Ivanov AY, Petrov AE, Vershinina EA, Galagudza MM, and Vlasov TD
- Subjects
- Adult, Arteries pathology, Blood Flow Velocity physiology, Cerebrovascular Circulation physiology, Endothelium pathology, Female, Hemodynamics, Humans, Jugular Veins pathology, Male, Brain blood supply, Cerebral Veins pathology, Embolization, Therapeutic, Intracranial Arteriovenous Malformations pathology, Intracranial Arteriovenous Malformations therapy
- Abstract
Cerebral venous drainage is generally believed to be regulated primarily by hydrodynamic forces. To gain further insight into the regulation of this process, we investigated the response of blood flow velocity and cross-sectional area (CSA) of the internal jugular veins (IJVs) to local hemodynamic shifts. All procedures and assessments were performed on patients (n = 30) undergoing embolization of brain arteriovenous malformations (AVMs). The procedure efficiency was verified by the postembolization reduction in time-averaged maximum blood flow velocities, as well as the elevation of pulsatility index and resistance index in the arterial feeders. In cerebral veins, the dominant IJV pressure remained unchanged during the procedure. At the same time, AVM embolization caused a significant reduction in maximal CSA (84 ± 7.6 to 68 ± 7.7 mm(2), P < 0.05) and minimal CSA (68 ± 7.0 to 51 ± 7.0 mm(2), P < 0.01) of the IJV located ipsilateral to the AVM, while the maximal linear blood flow velocity in the IJV remained unchanged (71 ± 4.9 and 85 ± 8.4 cm/s, P = 0.098). Consistent with previously published studies, the data obtained provide further evidence of active regulation of the venous outflow, probably mediated by certain neurogenic and/or endothelium-dependent mechanisms.
- Published
- 2013
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33. The antifungal effect of cellobiose lipid on the cells of Saccharomyces cerevisiae depends on carbon source.
- Author
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Trilisenko LV, Kulakovskaya EV, Kulakovskaya TV, Ivanov AY, Penkov NV, Vagabov VM, and Kulaev IS
- Abstract
The cellobiose lipid of Cryptococcus humicola, 16-(tetra-O-acetyl-β-cellobiosyloxy)-2-hydroxyhexadecanoic acid, is a natural fungicide. Sensitivity of the cells of Saccharomyces cerevisiae to the fungicide depends on a carbon source. Cellobiose lipid concentrations inducing the leakage of potassium ions and ATP were similar for the cells grown in the medium with glucose and ethanol. However, the cells grown on glucose and ethanol died at 0.05 mg ml(-1) and 0.2 mg ml(-1) cellobiose lipid, respectively. Inorganic polyphosphate (PolyP) synthesis was 65% of the control with 0.05 mg ml(-1) cellobiose lipid during cultivation on ethanol. PolyP synthesis was not observed during the cultivation on glucose at the same cellobiose lipid concentration. The content of longer-chain polyP was higher during cultivation on ethanol. We speculate the long-chained polyP participate in the viability restoring of ethanol-grown cells after treatment with the cellobiose lipid.
- Published
- 2012
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34. Interaction of Gram-negative bacteria with cationic proteins: Dependence on the surface characteristics of the bacterial cell.
- Author
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Prokhorenko IR, Zubova SV, Ivanov AY, and Grachev SV
- Abstract
Gram-negative bacteria can enter the bloodstream and interact with serum cationic proteins. The character of interaction will depend on the surface characteristics of bacterial cells, which are determined by bacterial chemotype and density of lipopolysaccharide (LPS) packing in the cell wall. It was shown that the lysozyme treatment resulted in the increase sensitivity to hypotonic shock. Significant differences to this effect were found between Escherichia coli strain D21 and D21f2 under treatment with physiological protein concentration. On the basis of electrokinetic measurements and studies of the interaction of cells with lysozyme, the hypothesis was formed that the cell wall of the E. coli strain D21f2 contains more LPS and has a higher density of their packing than the cell wall of the E. coli D21 cells. The effect of lysozyme and lactoferrin on the viability of E. coli cells of two different strains was examined. Lysozyme was found to more effectively inhibit the growth of the E. coli D21 bacteria, and lactoferrin suppressed mainly the growth of the E. coli D21f2 bacteria. These results indicate that the differences in LPS core structure of bacterial R-chemotype, which determines surface charge and density of LPS packing, plays an essential role in the mechanisms of interaction of the cationic proteins with the cell wall.
- Published
- 2009
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35. Vibrational analysis of alpha-D-glucose trapped in Ar matrix.
- Author
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Kovács A and Ivanov AY
- Subjects
- Gases chemistry, Hydrogen Bonding, Quantum Theory, Spectroscopy, Fourier Transform Infrared, Vibration, Volatilization, Glucose chemistry
- Abstract
The FT-IR spectra of alpha-D-glucose have been investigated by means of matrix-isolation FT-IR spectroscopy in the 3700-200 cm-1 range and by B3LYP/6-311++G** density functional calculations. The joint analysis of the experimental and computed IR spectra supported the expected predominance of the most stable gg and gt conformers in the vapor phase and the minor contribution of the less stable tg conformer. Weak absorption bands at the edge of the OH stretching region are in agreement with small amounts of analogous conformers with clockwise arrangement of the hydrogen bonds (c-gg, c-gt, c-tg). The assignment of the IR spectra was carried out on the basis of the computed harmonic force field using the scaled quantum mechanical method of Pulay. Scale factors developed previously for the B3LYP/6-311++G** level proved to be well transferable except that for the OH torsion. The latter scale factor was adjusted on the basis of the present experimental data. On the basis of the calculated results, 99 bands have been assigned to the gg, gt, and tg conformers of alpha-D-glucose with average deviations of 5.0, 5.9, and 6.1 cm-1, respectively.
- Published
- 2009
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36. Single dust-particle rotation in glow-discharge plasma.
- Author
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Karasev VY, Dzlieva ES, Eikhval'd AI, Ermolenko MA, Golubev MS, and Ivanov AY
- Abstract
Rotation of a single dust granule (spin) is investigated experimentally in a stratified glow discharge. We employ the technique of measurement of the angular velocity, which is based on coordinate tracing of the light scattered by a hollow transparent particle. The angular velocity measured in the experiment is about 1-2 orders of magnitude higher than observed in previous experiments. We found that the angular velocity depends linearly on the discharge current. The mechanism of rotation of the granule is also described.
- Published
- 2009
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37. Efflux of potassium ions from cells and spheroplasts of Saccharomyces cerevisiae yeast treated with silver and copper ions.
- Author
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Vagabov VM, Ivanov AY, Kulakovskaya TV, Kulakovskaya EV, Petrov VV, and Kulaev IS
- Subjects
- Biological Transport, Active, Ion Transport, Proton-Translocating ATPases metabolism, Saccharomyces cerevisiae enzymology, Saccharomyces cerevisiae Proteins metabolism, Spheroplasts enzymology, Spheroplasts metabolism, Copper metabolism, Potassium metabolism, Saccharomyces cerevisiae metabolism, Silver metabolism
- Abstract
Silver ions induce the efflux of potassium from cells of the yeast Saccharomyces cerevisiae but have no such effect on spheroplasts. Copper ions and the natural fungicide 2-O-3-hydroxyhexanoyl-beta-D-glucopyranosyl-(1-->4)-(6-O-acetyl-beta-D-glucopyranosyl-(1-->16)-2,15,16-trihydroxyhexadecanoic acid) induce the efflux of potassium ions from both cells and spheroplasts of S. cerevisiae. Silver and copper ions inhibit the activity of the plasma membrane H+-ATPase during the treatment of both cells and spheroplasts. It is supposed that the inability of silver ions to stimulate potassium efflux from spheroplasts results from damage to some components of K+ transport systems during preparation of spheroplasts.
- Published
- 2008
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38. Rotational motion of dusty structures in glow discharge in longitudinal magnetic field.
- Author
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Karasev VY, Dzlieva ES, Ivanov AY, and Eikhvald AI
- Abstract
The investigation of dust structure formed in glow discharge in an external longitudinal magnetic field with induction up to 400 G applied is presented in this work. The dust structure starts to rotate in the magnetic field. The angular-velocity magnitude is one to two orders larger than one in other discharge types. Its dependence on the magnetic field is nonmonotonic. The rotation direction inverses with an increase of the magnetic induction value up to a certain magnitude B0. In close range of induction around B0 and under certain conditions the rotation of the upper and lower parts of the structure in the opposite direction is observed. Rotation is caused by the ion-drag force. The inversion of rotation direction relates with the change of plasma flows in the area of their formation in stratum with the magnetic field applied. The effect of ion flows was investigated in two additional experiments on the observation of structure rotation onset and on gravity-driven probing of stratum. The angular-velocity unhomogeniety allowed us to investigate shearing and to observe melting of the dust crystal. The correlation functions approach showed the occurrence of structure transformation and its phase transition of the meltinglike type in the magnetic field.
- Published
- 2006
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39. Conformational structures and vibrational spectra of isolated pyrimidine nucleosides: Fourier transform infrared matrix isolation study of 2-deoxyuridine.
- Author
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Ivanov AY, Krasnokutski SA, Sheina G, and Blagoi YP
- Subjects
- Computational Biology methods, Spectroscopy, Fourier Transform Infrared, Chemistry Techniques, Analytical methods, Deoxyuridine chemistry
- Abstract
The conformational structures of 2-deoxyuridine (dU) were investigated using Fourier transform infrared (FTIR) matrix isolation spectroscopy. For the first time the FTIR spectra of dU in Ar matrices were obtained in the range 4000-200 cm(-1). The stabilities of conformers were estimated by the methods HF/3-21G (p), HF/6-31G (d,p) and MP2/6-31G (d,p). Ab initio calculations of the infrared spectra were performed by the methods HF/3-21G (p) and HF/6-31G (d,p). The actual occupancy of conformational isomers in matrix samples was determined. It was shown that anti-conformers of dU are dominant. The ribose rings of the main anti-conformers dU _a0, dU _a1 are in the C2'-endo conformation, but the ribose rings of minor anti-conformers dU_a2, dU_a3 have the C3'-endo conformation, stabilized by intramolecular hydrogen bonds O3'H...O5' and O5'H...O3', accordingly. Syn-conformers of dU are stabilized by the intramolecular hydrogen bond O5'H...O2 and the dominant conformation of the ribose ring is C2'-endo.
- Published
- 2003
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40. Slow inhibitory postsynaptic potentials and hyperpolarization evoked by noradrenaline in the neurones of mammalian sympathetic ganglion.
- Author
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Ivanov AY and Skok VI
- Subjects
- Animals, Electric Stimulation, Evoked Potentials drug effects, Neural Inhibition drug effects, Phentolamine pharmacology, Rabbits, Receptors, Adrenergic, alpha physiology, Synaptic Transmission drug effects, Ganglia, Sympathetic drug effects, Norepinephrine pharmacology
- Abstract
Slow IPSPs evoked in the neurones of rabbit isolated superior cervical ganglion by repetitive orthodromic stimulation, and a response evoked in the neurones of this ganglion by perfusion of noradrenaline, were studied using intracellular microelectrodes. Slow IPSPs were observed in 36% of neurones studied, and when investigated after treatment with D-tubocurarine and neostigmine, had a mean amplitude of 4.4 +/- 0.2 mV (mean +/- S.E.) and duration of 5 sec to 1.5 min. Two types of slow IPSPs occurring in different neurones were found. The slow IPSP of the first type was followed by a decrease in cell input resistance, was increased by depolarization and decreased by hyperpolarization of the membrane, with the reversal potential, if estimated by extrapolation method, equal to -77.8 +/- 3.3 mV. The slow IPSP of the second type was not followed by any change in cell input resistance, was increased by hyperpolarization and decreased by depolarization. The slow IPSP of the second type was reversibly blocked by phentolamine (1.4 X 10(-4) M). Noradrenaline (1 X 10(-4) M) evoked hyperpolarization or hyperpolarization followed by depolarization in 55% of the neurones studied. Hyperpolarization evoked by noradrenaline had a mean amplitude to 5.0 +/- 0.2 mV, was not followed by any change in cell input resistance, was reversibly blocked by phentolamine (1.4 X 10(-4) M), and was decreased by both depolarization and hyperpolarization of the cell membrane. It has been concluded that there are two groups of neurones in superior cervical ganglia, different with respect to the ionic mechanisms underlying the slow IPSP. In the first group of neurones the slow IPSP is probably due to an increase in potassium permeability of the membrane. The ionic mechanisms underlying the slow IPSP in the second group of neurones of noradrenaline-induced hyperpolarization remain unclear.
- Published
- 1980
- Full Text
- View/download PDF
41. What is the ongoing activity of sympathetic neurons?
- Author
-
Skok VI and Ivanov AY
- Subjects
- Animals, Autonomic Fibers, Preganglionic physiology, Electric Stimulation, Evoked Potentials, Ganglia, Sympathetic physiology, Neurons physiology, Rabbits, Synapses physiology, Sympathetic Nervous System physiology, Synaptic Transmission
- Abstract
The patterns of tonic activity were recorded with intracellular electrodes from the neurons of rabbit superior cervical ganglion whose preganglionic inputs remained intact, and were compared with the responses of the same neurons to single stimuli applied to preganglionic fibers. It was found found that each neuron received two preganglionic inputs, dominant and accessory. Dominant input is formed by one preganglionic fiber with a potent synaptic action on the neuron evoking spikes with high safety factor. Accessory input is formed by two or more converging preganglionic fibers that can evoke spikes only through summation of their EPSPs. It is suggested that preganglionic fibers evoking accessory spikes in each particular neuron are discharged by common presynaptic source, and that dominant spikes, accessory spikes and ineffective EPSPs in tonic activity of the ganglion neuron are each produced by separate central generators.
- Published
- 1983
- Full Text
- View/download PDF
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