Publications by authors named "Alexander Chernyak"

Cystic fibrosis (CF) is a hereditary disease characterized by the progression of respiratory disorders, especially in adult patients. The purpose of the study was to identify volatile organic compounds (VOCs) as predictors of respiratory dysfunction, chronic respiratory infections of , , , and VOCs associated with severe genotype and highly effective modulator treatment (HEMT). Exhaled breath samples from 102 adults with CF were analyzed using PTR-TOF-MS, obtained during a forced expiratory maneuver and normal quiet breathing.

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Background: Proton-transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS) is a promising tool for a rapid online determination of exhaled volatile organic compounds (eVOCs) profiles in patients with cystic fibrosis (CF).

Objective: To detect VOC breath signatures specific to adult patients with CF compared with controls using PTR-TOF-MS.

Methods: 102 CF patients (54 M/48, mean age 25.

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In this article, the specific features of competitive ionic and molecular transport in nanocomposite systems based on network membranes synthesized by radical polymerization of polyethylene glycol diacrylate in the presence of LiBF, 1-ethyl-3-methylimidazolium tetrafluoroborate, ethylene carbonate (EC), and TiO nanopowder (d~21 nm) were studied for H, Li, B, C, and F nuclei using NMR. The membranes obtained were studied through electrochemical impedance, IR-Fourier spectroscopy, DSC, and TGA. The ionic conductivity of the membranes was up to 4.

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The hydration of ions and charge groups controls electro mass transfer through ion exchange systems. The self-diffusion and local mobility of water molecules as well as lithium cations in poly (4-styrenesulfonic acid) and its lithium, sodium and cesium salts were investigated for the first time using pulsed-field gradient NMR (PFG NMR) and NMR relaxation techniques. The temperature dependences of the water molecule and Li cation self-diffusion coefficients exhibited increasing self-diffusion activation energy in temperature regions below 0 °C, which is not due to the freezing of parts of the water.

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Elementary processes of electro mass transfer in the nanocomposite polymer electrolyte system by pulse field gradient, spin echo NMR spectroscopy and the high-resolution NMR method together with electrochemical impedance spectroscopy are examined. The new nanocomposite polymer gel electrolytes consisted of polyethylene glycol diacrylate (PEGDA), salt LiBF and 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF) and SiO nanoparticles. Kinetics of the PEGDA matrix formation was studied by isothermal calorimetry.

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The interconnection of ionogenic channel structure, cation hydration, water and ionic translational mobility was revealed in Nafion and MSC membranes based on polyethylene and grafted sulfonated polystyrene. A local mobility of Li, Na and Cs cations and water molecules was estimated via the H, Li, Na and Cs spin relaxation technique. The calculated cation and water molecule self-diffusion coefficients were compared with experimental values measured using pulsed field gradient NMR.

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The effect of the composition of liquid electrolytes in the bulk and at the interface with the LiFePO cathode on the operation of a solid-state lithium battery with a nanocomposite polymer gel electrolyte based on polyethylene glycol diacrylate and SiO was studied. The self-diffusion coefficients on the 7Li, 1H, and 19F nuclei in electrolytes based on LiBF and LiTFSI salts in solvents (gamma-butyrolactone, dioxolane, dimethoxyethane) were measured by nuclear magnetic resonance (NMR) with a magnetic field gradient. Four compositions of the complex electrolyte system were studied by high-resolution NMR.

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Article Synopsis
  • Fullerene derivatives have significant potential in science and technology due to their strong anticancer, antiviral, and antibacterial properties, which are influenced by how these molecules group together.
  • This research investigates the size and stability of fullerene derivative associates in various solvents, using NMR techniques to understand their movement and interactions better.
  • Key findings include the calculation of molecule sizes, lifetimes of associates, and how these derivatives interact with erythrocytes, indicating that they attach to cell surfaces and move through lateral diffusion.
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NMR is the method of choice for molecular and ionic structures and dynamics investigations. The present review is devoted to solvation and mobilities in solid electrolytes, such as ion-exchange membranes and composite materials, based on cesium acid sulfates and phosphates. The applications of high-resolution NMR, solid-state NMR, NMR relaxation, and pulsed field gradient H, Li, C, F, Na, P, and Cs NMR techniques are discussed.

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This review is devoted to different types of novel polymer electrolytes for lithium power sources developed during the last decade. In the first part, the compositions and conductivity of various polymer electrolytes are considered. The second part contains NMR applications to the ion transport mechanism.

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Here we report a reaction of the fullerene derivatives CArCl, which enables the substitution of Cl with thiophene residues and the formation of the novel family of -symmetrical C fullerene derivatives with six functional addends CArTh. The discovered reaction provided a straightforward approach to the synthesis of previously inaccessible multifunctional water-soluble fullerene derivatives, including the compounds with antiviral activity against human immunodeficiency and influenza viruses.

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The results of NMR, and especially pulsed field gradient NMR (PFG NMR) investigations, are summarized. Pulsed field gradient NMR technique makes it possible to investigate directly the partial self-diffusion processes in spatial scales from tenth micron to millimeters. Modern NMR spectrometer diffusive units enable to measure self-diffusion coefficients from 10 m/s to 10 m/s in different materials on H, H, Li, C, F, Na, P, Cs nuclei.

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Cystic fibrosis (CF) is the most common monogenic autosomal recessive disease, associated with pathogenic variants in the CFTR gene. The splicing variant c.3140-16T>A (3272-16T>A) has been described previously and, according to the Russian CF Patients Registry, occurs with a frequency of 0.

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Cyclic oxoammonium salts and DMSO are known as important reagents for their diverse and unique reactivity. In the present work, we have studied the reaction of six- and five-membered oxoammonium salts with DMSO. The reaction includes ∼100% selective transfer of the O atom from the >N═O group to the S atom of DMSO and structural rearrangement of the remaining cationic framework, leading to the formation of hydrolytically unstable iminium salts.

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The main particularities of sulfonate groups hydration, water molecule, and alkaline metal cation translation mobility were revealed by nuclear magnetic resonance (NMR) and ionic conductivity measurements techniques in cation-exchange membranes MSC based on cross-linked sulfonated polystyrene (PS) grafted on polyethylene with ion-exchange capacity of 2.5 mg-eq/g. Alkaline metal cation hydration numbers (h) calculated from temperature dependences of H chemical shift of water molecule for membranes equilibrated with water vapor at RH = 95% are 5, 6, and 4 for Li, Na, and Cs ions, respectively.

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Recently developed non-functional derivatives of polymethylsilsesquioxane (PMSSO) dendrimers of the first to fifth generation were characterized by 1H, 13C and 29Si NMR spectroscopy. The self-diffusion and NMR relaxation of PMSSO dendrimers in dilute solutions of toluene and melts were investigated in a wide temperature range (-50-80 °C). The hydrodynamic radii of dendrimers were determined from the self-diffusion coefficients measured in diluted solutions according to the Stokes-Einstein equation.

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We have synthesized a series of water-soluble polycarboxylic derivatives of [60]fullerene with a gradually changed polarity by combining three to five polar (ionic) malonate addends with two to zero hydrophobic dichlorobenzene units and explored their antiviral activity. It has been shown that decreasing the number of the ionogenic carboxylic groups in the molecules enhanced their antiviral activity against HIV-1 and suppressed their action against HIV-2. The obtained results implied that the charged states and hydrophobicity of the water-soluble polycarboxylic fullerene derivatives affect significantly their biological properties.

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We report novel synthetic routes for facile preparation of highly functionalized fullerene derivatives C(OR)X (X = H, Cl, Br), C(OR)O and C(OR) from chlorofullerene CCl. The first water-soluble fullerene compound bearing residues of 3-oxypropanoic acid demonstrated a potent anti-HIV activity.

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C and N NMR spectra of high-energy 2,4,6-triazidopyridine-3,5-dicarbonitrile, 2,3,5,6-tetraazidopyridine-4-carbonitrile and 3,4,5,6-tetraazidopyridine-2-carbonitrile are reported. The assignment of signals in the spectra was performed on the basis of density functional theory calculations. The molecular geometries were optimized using the M06-2X functional with the 6-311+G(d,p) basis set.

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2,4,6-Triazido-s-triazine, 2,4,6-triazidopyrimidine and six different 2,4,6-triazidopyridines were studied by (15)N NMR spectroscopy. The assignment of signals in the spectra was performed using the gauge-independent atomic orbital (GIAO)-Tao-Perdew-Staroverov-Scuseria exchange-correlation functional (TPSS)h/6-311+G(d,p) calculations on the M06-2X/6-311+G(d,p) optimized molecular geometries. The Truhlar and coworkers' continuum solvation model called SMD was applied to treat solvent effects.

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We report Arbuzov-type reactions of chlorofullerene C(60)Cl(6) with trialkyl phosphites producing highly functionalized fullerene derivatives C(60)[P(O)(OR)(2)](5)H with high yields. The designed family of [60]fullerene phosphonic acids and their esters showed unusual properties which might find valuable material science applications.

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