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511.
Nadezhda L. Volkova 《Thermochimica Acta》2005,435(1):108-112
Titration calorimetric, densimetric and viscosimetric measurements have been combined to study the interactions of 18-crown-6 with d-glucose and d-galactose in water. The crown ether forms a thermodynamically stable 1:1 complex with d-galactose but not with d-glucose. These observations are explained in terms of the stereochemistry of the monosaccharide molecules. 相似文献
512.
Maxim E. Zhidkov Nadezhda N. Balaneva Oleg S. Radchenko Sergey V. Dubovitskii 《Tetrahedron letters》2007,48(45):7998-8000
A simple and practical approach for the synthesis of the marine sponge pigment fascaplysin was used for the total syntheses of its natural derivatives, the marine alkaloids 3-bromofascaplysin, 10-bromofascaplysin, and 3,10-dibromofascaplysin. The conditions of each step were revised, and as a result these compounds were produced by identical procedures with total yields of 40-43%. 相似文献
513.
S. D. Varfolomeyev E. A. Zaitseva T. A. Osipova 《Applied biochemistry and biotechnology》1996,61(1-2):173-188
The article describes the research activities in the field of enzyme engineering in Russia. The discussion is focused on fundamental
studies of biocatalytic processes that expand utilization of enzymes, biocatalytic synthesis of organic products from renewable
raw mate rials, enzymes for hydrolysis of cellulose and lignocellulose materials, immobilized cells, new enzyme-based drugs,
enzymes in fine organic synthesis, bioanalytic devices, biosensors, and biofuels. 相似文献
514.
Nataliya E. Novikova Timofei A. Sorokin Alexander M. Antipin Nadezhda B. Bolotina Olga A. Alekseeva Nataliya I. Sorokina Valentina I. Voronkova 《Acta Crystallographica. Section C, Structural Chemistry》2019,75(6):740-749
Crystals with the La18W10O57‐type structure (6H and 5H polytypes) were obtained by a self‐flux method from high‐temperature solutions. Some of the crystal samples were studied by single‐crystal X‐ray structure analysis. The diffraction patterns indicated that two phases co‐exist in each sample. The hexagonal lattices have a common period of a ≈ 9.0 Å and are non‐equal in length but have equally oriented superstructure periods 6c (phase I) and 5c (phase II), c ≈ 5.4 Å. The structures of phases I and II were solved in the symmetry groups P2c and P321, respectively, based on the X‐ray data for crystals I and II, with predominant content of the first and second phase. The motif of isolated WO6 prisms with W atoms on the cell edges is common to both phases. WO6 octahedra, both isolated and joined by faces, are distributed along the c axis within the unit cells. Phase I contains extra layers of isolated WO6 octahedra compared to phase II. Tungsten sites in joined octahedra are disordered and partially occupied. Disordering is more expressed in phase II, which in return contains rather more W and O per atom of La. The refined chemical compositions are La18W10O57 for I and La15W8.5O48 for II. 相似文献
515.
Partial hydrogen ion conductivity in acceptor doped CaTiO(3), BaCeO(3) and ZrO(2) and nominally undoped BaTiO(3) and TiO(2) has been investigated by transport number measurements using the hydrogen concentration cell/EMF method in wet atmospheres as a function of pO(2)(10(-20)-1 atm) at 800 or 1000 [degree]C. All oxides investigated, except ZrO(2), show minor proton conductivity in oxidising atmospheres. Earlier indications of apparent negative charge transport by hydrogen under reducing conditions and high temperatures in SrTiO(3) samples have been reproduced for all the investigated oxides including ZrO(2). 相似文献
516.
Konstantin S. Mineev Sergey A. Goncharuk Marina V. Goncharuk Natalia V. Povarova Anatolii I. Sokolov Nadezhda S. Baleeva Alexander Yu. Smirnov Ivan N. Myasnyanko Dmitry A. Ruchkin Sergey Bukhdruker Alina Remeeva Alexey Mishin Valentin Borshchevskiy Valentin Gordeliy Alexander S. Arseniev Dmitriy A. Gorbachev Alexey S. Gavrikov Alexander S. Mishin Mikhail S. Baranov 《Chemical science》2021,12(19):6719
One of the essential characteristics of any tag used in bioscience and medical applications is its size. The larger the label, the more it may affect the studied object, and the more it may distort its behavior. In this paper, using NMR spectroscopy and X-ray crystallography, we have studied the structure of fluorogen-activating protein FAST both in the apo form and in complex with the fluorogen. We showed that significant change in the protein occurs upon interaction with the ligand. While the protein is completely ordered in the complex, its apo form is characterized by higher mobility and disordering of its N-terminus. We used structural information to design the shortened FAST (which we named nanoFAST) by truncating 26 N-terminal residues. Thus, we created the shortest genetically encoded tag among all known fluorescent and fluorogen-activating proteins, which is composed of only 98 amino acids.We solved the structure of a fluorogen-activating protein FAST and synthesized the library of potential fluorogens. Using these data, we designed the shortest genetically encoded fluorescent tag among all known. 相似文献
517.
Diblock polyampholytes grafted onto spherical particles: Monte Carlo simulation and lattice mean-field theory 总被引:1,自引:0,他引:1
Akinchina A Shusharina NP Linse P 《Langmuir : the ACS journal of surfaces and colloids》2004,20(23):10351-10360
Spherical brushes composed of diblock polyampholytes (diblock copolymers with oppositely charged blocks) grafted onto solid spherical particles in aqueous solution are investigated by using the primitive model solved with Monte Carlo simulations and by lattice mean-field theory. Polyampholyte chains of two compositions are considered: a copolymer with a long and a short block, A100B10, and a copolymer with two blocks of equal length, A50B50. The B block is end-grafted onto the surface, and its charge is varied, whereas the charge of the A block is fixed. Single-chain properties, radial and lateral spatial distributions of different types, and structure factors are analyzed. The brush structure strongly depends on the charge of the B block. In the limit of an uncharged B block, the chains are stretched and form an extended polyelectrolyte brush. In the other limit with the charges of the blocks compensating each other, the chains are collapsed and form a polyelectrolyte complex surrounding the particles. At intermediate charge conditions, a polyelectrolyte brush and a polyelectrolyte complex coexist and constitute two substructures of the spherical brush. The differences of the brush structures formed by the A100B10 and A50B50 polyampholytes are also analyzed. Finally, a comparison of the predictions of the two theoretical approaches is made. 相似文献
518.
S. Yu. Burylin Z. G. Osipova V. D. Sokolovskii 《Reaction Kinetics and Catalysis Letters》1982,18(1-2):17-20
Studies of the effect of phosphorus and tungsten on the basicity and catalytic properties of catalysts for oxidative ammonolysis of propane indicate that, besides the common decrease in the number of active centers on the catalyst surface, the sharply decrease the concentration of strong basis centers.
. , , , .相似文献
519.
Aleksei B. Sheremetev Nadezhda V. Palysaeva Marina I. Struchkova 《Mendeleev Communications》2010,20(6):350-352
Oxidation of 3-amino-4-[(s-tetrazin-3-yl)amino]furazans with peroxy acids or 30% H2O2/Na2WO4/H2SO4 system results in transformation of the amino group into the nitro one and is accompanied by formation of N-oxides at tetrazine moiety. 相似文献
520.