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1.
Studying Intermolecular Processes in Thin Surface Layers with Microcantilever Transducers. Formation of Protein Fibrils on a Solid Support G. A. Kiselev, P. V. Kudrinskii, I. V. Yaminskii, and O. I. Vinogradova Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences,Leninskii pr. 31, Moscow, 119991 Russiae-mail:
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Received April 23, 2008 Abstract — The possibility of studying the processes of intermolecular interaction in thin surface layers by means of microcantilever transducer (MCT) are considered. The use of MCT makes it possible to observe the catalytic growth of amyloid fibrils from chemically immobilized lisozyme molecules on the gold or silicon supports at enhanced acidity (pH 3.0) and room temperature, whereas aggregation in the volume occurs under the same conditions at a higher temperature of 57  . Forces that arise in the monolayer protein films during their aggregation are analyzed. A correlation is revealed between the development of lateral strains and the growth rate of protein fibrils in the monolayer. It is shown that for a protein covalently immobilized on the silicon (mica) surface, the aggregation rate is 4.6 (as revealed by the analysis of kinetic data on the caltilever bending) and 5 times (according to estimates of the number of fibrils in an AFM image) slower than on the gold surface. A model for calculating the pair interactions between protein molecules in a monolayer during their aggregation is proposed. Using this model and based on the experimental data, the pair interaction forces of lysozyme molecules on the gold and silicon surfaces are calculated. The calculated forces coincide in the order of magnitude with the data of force spectroscopy on the artificial expansion of an aggregate of lysozyme molecules T4 [23]. It is confirmed experimentally that chemical immobilization of lysozyme on the mica surface leads to deformation (flattening) of protein molecules as compared with their native conformation. PACS numbers: 07.79.Lh, 87.64.Dz DOI: 10.1134/S0033173208060015
24/11/2008 | 1136 Посещения | Печать
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2.
Transfer and Deposition of Carbon- and Nitrogen-containing Radicals and Ions Produced by Glow Discharge in Hydrogen/Methane/Nitrogen Mixtures A. E. Gorodetskiia, R. Kh. Zalavutdinova, V. L. Bukhovetsa, A. P. Zakharova, G. T. Razdobarin†,b, E. E. Mukhinb, and V. V. Semenovb a Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences,
Leninskii pr. 31, Moscow, 119991 Russia b Ioffe Physicotechnical Institute, Russian Academy of Sciences, Politekhnicheskaya ul. 26, St. Petersburg, 194021 Russia E-mail:
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Received November 11, 2007 Abstract — Transfer and deposition of the decomposition products of a dc glow discharge with hollow cathode in a hydrogen/methane flow are discussed. Hydrocarbon (a-C:H) films were deposited at inner surfaces of the hollow cathode and quartz tube bounded the discharge. The carbon deposition rate in the hollow cathode was 3–10 times higher than in the positive column and in afterglow range. Acetylene, ethylene, and ethane prevailed in the plasma-reaction gaseous products. When molecular nitrogen was introduced to the near-cathode plasma at a flow rate equal to or higher than that of methane, the carbon deposition rate at the cathode inner surfaces dropped down by 1.5 to 2 orders of magnitude. The carbon that has been consumed in the a-C:H films formation in the cathode is now transformed mainly to hydrogen cyanide (HCN). The carbon deposition rate in the positive column and in afterglow range (T = 300 K) were comparable with those in the H2/CH4 mixture. In the a-C/N:H deposits, the nitrogen concentration was 15 to 25 at %. The experiments showed that nitrogen can be used as a component of the gas flow specially introduced near the mirror in protecting the optical surfaces in diagnostic channels of the ITER tokamak against a-C:H film deposition. PACS numbers: 52.77.Bn; 52.77.Dq; 81.05.Uw; 81.15.Jj DOI: 10.1134/S0033173208060027
24/11/2008 | 1197 Посещения | Печать
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3.
The Effect of Atomic Hydrogen on the Anodic Dissolution of Iron in a Sulfate Electrolyte Studied with Impedance Spectroscopy M. A. Maleeva, A. A. Rybkina, A. I. Marshakov, and V. V. Elkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninskii pr. 31, Moscow, 119991 Russia E-mail:
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Received May 3, 2008 Abstract — Impedance spectra of an iron membrane electrode are recorded in a range of the active metal dissolution potentials in an acidic sulfate solution. The rate constants of the elementary adsorption stages of iron dissolution are found to decrease with an increase in the amount of atomic hydrogen. This results in a decrease in the metal surface coverage with intermediate particles of the anodic process. PACS numbers: 82.45.Qr DOI: 10.1134/S0033173208060039
24/11/2008 | 1132 Посещения | Печать
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4.
Effect of Anodic Surface Treatment of Cobalt Silicides on the Hydrogen Evolution Reaction V. S. Povroznik, A. B. Shein, and I. N. Mikova Perm' State University, ul. Bukireva 15, Perm’, 614600 Russia E-mail:
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Received April 17, 2007 Abstract — Effect of the anodic surfaces treatment of cobalt silicides with different content of the metal and silicon components on the mechanism and kinetics of hydrogen evolution in acid solutions is studied. PACS numbers: 82.45.Qr DOI: 10.1134/S0033173208060040
24/11/2008 | 1149 Посещения | Печать
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5.
Adsorption Properties of Synthetic Piceatannol K. E. Polunin, P. N. Kolotilov, D. V. Dzardanov, A. V. Larin, and I. A. Polunina Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences,
Leninskii pr. 31, Moscow, 119991 Russia E-mail:
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Received July 2, 2008 Abstract — The adsorption isotherms of synthetic piceatannol (trans-3,5,3',4'-tetrahydroxystilbene) from n hexane–ethyl acetate at nanodispersed silicon, titanium, and aluminum oxides were measured under static conditions. The adsorption properties of piceatannol and other hydroxystilbenes were compared with those of polyphenols. It was found that piceatannol adsorbs at titanium oxide better than at alumina and silica and almost as well as phloroglucinol adsorbs at these oxides. The adsorption isotherms can be satisfactorily approximated by the Freundlich equation for the model of localized adsorption at energetically heterogeneous sites. The influence of the nature and concentration of the polar components of a binary organic solvent on the adsorption of piceatannol at silica gel was studied by normal-phase chromatography and UV spectroscopy. The dependences of the retention factors of piceatannol and other hydroxystilbenes on the solvent composition were described by a simple analytical equation. The optimum composition of the mobile phase for separation of piceatannol and other stilbenoids was found. PACS numbers: 82.45.Qr DOI: 10.1134/S0033173208060052
24/11/2008 | 1127 Посещения | Печать
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6.
Supramolecular Bisporphyrin Cages: Design and Ways of Self-Assembly of Supramolecular Bisporphyrin Structures for Molecular Nanomotors and Nanosensors Yu. P. Yashchuk, V. S. Tyurin, and I. P. Beletskaya Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences,
Leninskii pr. 31, Moscow, 119991 Russia E-mail:
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Received March 6, 2008 Abstract — Self-assembly of supramolecular ensembles of coordination bisporphyrins was studied in reactions of meso-tetrakis(3-hydroxyphenyl)porphyrinatozinc with LaCl3, MnCl2, CrCl3, and SnCl2 and exodentate ligands (1,4-diazabicyclo[2.2.2]octane and 4,4'-bipyridyl). A design and ways of self-assembly of bisporphyrins structures were developed. PACS numbers: 81.16.Fg DOI: 10.1134/S0033173208060064
24/11/2008 | 1188 Посещения | Печать
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7.
Electrochemical Synthesis and Spectroelectrochemical Properties of Nanostructured Polyaniline Layers in the Presence of Various Polyamidosulfonic Acids A. A. Isakova, O. L. Gribkova, A. A. Nekrasov, V. F. Ivanov, V. A. Tverskoi*, and A. V. Vannikov Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences,
Leninskii pr. 31, Moscow, 119991 Russia E-mail:
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* Lomonosov State Academy of Fine Chemical Technology, pr. Vernadskogo 86, Moscow, 117571 Russia Received February 29, 2008 Abstract — Electrochemical matrix polymerization of nanostructured polyaniline layers in the presence of polyamidosulfonic acids differing in the rigidity of the polymer framework was studied in a wide concentration range. The spectroscopic, electrochemical, and morphological properties of the resulting layers were examined. It was found that the accelerated electropolymerization is due to (1) preliminary association of aniline with the sulfo groups of the polyacids and (2) a high local concentration of the protons near its macromolecule. The use of a polyacid with a rigid polymer framework afforded an interpolymer complex with polyaniline in side chains. With a semirigid matrix, both a two-strand complex (characteristic of an acid matrix with a flexible chain) and a branched complex were obtained. PACS numbers: 78.67.Bf DOI: 10.1134/S0033173208060076
24/11/2008 | 1214 Посещения | Печать
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8.
Nanostructure and Energy Properties of the Stainless Steel X18N10T Surface Studied by Scanning Tunneling Microscopy and Scanning Tunneling Spectroscopy. 2. Measurements at Different Potentials in HCl and H2SO4 Solutions. Yu. M. Stryuchkova and E. V. Kasatkin Karpov Institute of Physical Chemistry, ul. Vorontsovo pole 10, Moscow, 105054 Russia
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Received Fabruary 13 2008 Abstract — Stainless steel Kh18N10T is studied by electrochemical scanning tunneling microscopy (ESTM) and electrochemical scanning tunneling spectroscopy (ESTS) at the interface with solutions of 0.01 N HCl and 0.1 N H2SO4 at the controlled sample and tip potentials. The sample potential varied from –0.46 to +1.14 V in 0.01 N HCl and from –0.06 to +0.74 V (NHE) in 0.1 N H2SO4. It is shown that although in the studied acid solutions at the controlled potential the surface is smother than in air, this does not allow one to determine the extremal values of parameters  ,  , and  corresponding to individual properties of Fe, Cr, and Ni or their oxides. It is shown that compared to the steel nanorelief, the sample potential has a stronger effect on the electrophysical properties that determine the tunneling transfer of electrons. PACS numbers: 68.37.Ef, 81.07.-b DOI: 10.1134/S0033173208060088
24/11/2008 | 1165 Посещения | Печать
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9.
Formation of Metal (Iron)-Oxide Nanostructures and Nanocomposites by Reactive Sputtering and Low-Temperature Reoxidation V. A. Kotenev, D. N. Tyurin, A. Yu. Tsivadze, M. A. Petrunin, L. B. Maksaeva, and T. P. Puryaeva Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences,
Leninskii pr. 31, Moscow, 119991 Russia E-mail:
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Received February 5, 2008 Abstract — Morphology and composition of nanostructured metal-oxide coating prepared by iron reactive sputtering and subsequent low-temperature oxidation in air at 50°C were studied by atomic-force microscopy (with digital processing of images), X-ray diffraction, and resistance measurements. The growth kinetics of metaloxide nanoparticles constituting the sputtered metal-oxide composite was evaluated by the direct processing of surface AMF-images. According to the results of morphological studies after the low-temperature oxidation, the surface layer has complicated structure: the metal nanoparticles surrounded by the  Fe2O3 oxide phase merge to extended rod-like structures (globules) sized, on the average, 100–200 nm lengthwise, 20–30 nm in diameter. This structure allows explaining the coatings' functional properties important for their applications. PACS numbers: 81.07.Bc DOI: 10.1134/S003317320806009X
24/11/2008 | 1290 Посещения | Печать
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10.
The Effect of Silicon on Hyperfine Structure and Corrosion Electrochemical Behavior of Fe Cr Alloys O. V. Kasparova,* Yu. V. Baldokhin,** and M. O. Anosova*** * Karpov Institute of Physical Chemistry, ul. Vorontsovo Pole 10, Moscow, 105064 Russia E-mail:
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** Semenov Institute of Chemical Physics, Russian Academy of Sciences, ul. Kosygina 4, Moscow, 119991 Russia *** Moscow State Institute of Steel and Alloys, Leninskii pr. 4, Moscow, 119049 Russia Received September 15, 2007 Abstract — The effect of silicon on the corrosion–electrochemical behavior of iron alloys containing 15, 20, and 25% chromium in a 1 N H2SO4 solution at room temperature is investigated. With the use of Mössbauer spectroscopy, the hyperfine magnetic and electronic structure of the alloys is studied. With the Normos program package for processing spectra, the distribution function of hyperfine magnetic fields P(Hef), mean intensity of the effective magnetic field Hef, isomeric shift  , electric quadrupole splitting  eq, and other parameters are calculated. Spectroscopic data are compared to the results of polarization measurements. A correlation between the hyperfine structure and electrochemical behavior of the alloys in various potential ranges is found. PACS numbers: 76.80.+y; 82.45.Bb DOI: 10.1134/S0033173208060106
24/11/2008 | 1259 Посещения | Печать
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