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941.
Nourdin Ivan Peccati Giovanni Yang Xiaochuan 《Journal of Theoretical Probability》2022,35(3):2020-2037
Journal of Theoretical Probability - We establish explicit bounds on the convex distance between the distribution of a vector of smooth functionals of a Gaussian field and that of a normal vector... 相似文献
942.
Rubin Gulaboski Carlos M. Pereira M. Natalia D. S. Cordeiro Ivan Bogeski Fernando Silva 《Journal of Solid State Electrochemistry》2005,9(6):469-474
An electrochemical method for the detection of enzymatically created anions is described that uses a thin-film electrode with decamethylferrocene as an electroactive redox probe. The enzymatic oxidation of glucose with enzyme glucose oxidase produces gluconic acid as a final product. The oxidation of decamethylferrocene dissolved in the thin-nitrobenzene film, that is spread on the working graphite electrode and submerged in the aqueous solution containing glucose and glucose oxidase, is followed by the up-take of gluconate anions from the aqueous phase to nitrobenzene. The peak currents of the square-wave voltammetric responses of that system are a linear function of the glucose concentration in the milimolar range from 0.1 mmol/L to 0.7 mmol/L (R2=0.994). 相似文献
943.
Jurij Svete Branko Stanovnik Miha Tiler Ljubo Goli
Ivan Leban 《Journal of heterocyclic chemistry》1989,26(1):145-153
From heteroarylaminomethyleneoxazolones 4 , obtained from N-heteroarylformamidines 2 and 2-phenyl-5-oxo-4,5-dihydro-1,3-oxazole ( 3 ), the following β-heteroarylamino-α,β-dehydro-α-amino acid derivatives were prepared: methyl 8 and ethyl esters 9 , amides 10 and 11 , hydrazides 12 , and azides 15 . By catalytic hydrogenation the compounds 4 were converted into β-heteroarylamino substituted amides 18 and β-heteroarylamino-α-amino acids 20 . 相似文献
944.
ubica Tri
íkov Ivan Poto
k Christoph Wagner 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(4):m246-m248
The structure of the title compound, [Cu(C6H7N)2{Ag(CN)2}2]n, is made up of neutral zigzag chains of [–NC–Ag–CN–Cu(4‐Mepy)2{Ag(CN)2}–NC–Ag–CN–] (4‐Mepy is 4‐methylpyridine). Neighbouring chains are linked by weak argentophilic interactions, with Ag?Ag distances of 3.2322 (12) Å. The Cu atom, which lies on a twofold rotation axis, is pentacoordinated by one monodentate Ag(CN)2? anion [Cu—N 1.985 (3) Å], the atoms of which lie on the same rotation axis, and by bridging dicyanoargentate anions [2 × Cu—N 2.0827 (19) Å], with Ag atoms on inversion centres. The coordination polyhedron is completed by two 4‐Mepy molecules [2 × Cu—N 2.038 (2) Å], which occupy the axial positions of a distorted trigonal bipyramid. 相似文献
945.
Branko Kozuilić Ivančica Leuštek Branka Pavlović Pavao Mildner Slobodan Barbarić 《Applied biochemistry and biotechnology》1987,15(3):265-278
Each of the three high-mannose type glycoproteins studied, acid phosphatase, invertase, and glucose oxidase, could be specifically
cross-linked through its carbohydrate chains. The procedure involves periodate oxidation of carbohydrate residues followed
by reaction of the generated aldehyde groups with adipic acid dihydrazide as a cross-linker. The amount and size as well as
solubility of the formed polymers could be efficiently controlled by varying the reaction conditions, i.e., the oxidation
degree and the concentrations of glycoproteins, cross-linker, and hydrogen ions during the cross-linking reaction. It was
found that the quantity and size of polymers increased with oxidation degree and protein concentration and by lowering the
pH. When the protein concentration was above and pH below certain values, depending on the glycoenzyme, insoluble polymers
formed. The soluble cross-linked polymers retained a high level of original activity, and the minor decrease in specific activity
noticed was shown to occur during the periodate oxidation step. The cross-linked glycoenzymes are much more resistant to denaturation
by high temperature and by changes in pH, demonstrating the usefulness of this method in preparation of the stabilized glycoprotein
derivatives. 相似文献
946.
Spanik I Krupcik J Skacáni I Sandra P Armstrong DW 《Journal of chromatography. A》2005,1071(1-2):59-66
In this work, the separation of enantiomers of N-TFA-O-alkyl amino acids on the 2,3-di-O-pentyl-6-O-acyl alpha-, beta- and gamma-cyclodextrin stationary phases has been studied. The influence of structure differences in the alkyl substituents bonded to the stereogenic carbon atom (R1), as well as in the ester group (R2) of the selected amino acid derivatives, and the selectivity of modified alpha-, beta- and gamma-cyclodextrin phases in gas chromatographic separation of derivatized amino acid enantiomers was studied in detail. A model set of N-TFA-alkyl esters of four amino acids was separated on five columns. The separation of enantiomers was evaluated in terms of the interactions of the alkyl substituents bonded to the stereogenic carbon (R1) and/or the ester group (R2) of the N-TFA-O-alkyl amino acid derivatives as well as the nature of the 3-O-acyl group in the 2,6-di-O-pentyl-3-O-acyl alpha-, beta- and gamma-cyclodextrins. It was shown that the variation in the enantiomeric separation with temperature and the retention order of enantiomers on a given cyclodextrin capillary column depends both on the nature of the bonded R1 and R2 alkyl groups. It was found that the temperature dependencies of selectivity factors, ln alpha on 1/T, were mostly non-linear. The thermodynamic data [delta(deltaS) and [delta(deltaH)] which characterize the chiral recognition were used to gain more insight into the mechanistic aspects of enantio separation of the N-TFA-O-alkyl amino acid derivatives on 2,6-di-O-pentyl-3-O-acyl-alpha-, beta- and gamma-cyclodextrins. 相似文献
947.
Activation barriers of the title reactions are calculated using a DZ + P basis set with diffuse p functions on negative ions. In the correlation effects, which are large and negative, the importance of single and triple excitations is stressed. The barrier for the reaction of H? with CH3F is 12 kJ/mole, in good agreement with experiment, while the barrier for the reaction of F? with CH3F is predicted to be 14 kJ/mole. 相似文献
948.
Bruce N. Storhoff Daniel P. Harper Ivan H. Saval Jonathan H. Worstell 《Journal of organometallic chemistry》1981,205(2):161-166
Both (C6H5)2P(CH2)3CN and (C6H5)2P(CH2)4CN have been obtained from the reaction of Br(CH2)nCN (n = 3, 4) with (C6H5)2POCH3 followed by reduction with (C6H5)2SiH2. These phosphine-nitrile ligands form L2PdCl2 complexes which are shown by IR measurements to have trans geometries with the phosphine portions of the ligands coordinated. Reactions of o-BrC6H4CN with CH3(CH2)3Li followed by R2PCl (R = C6H5 or (CH3)2N) have been used to provide good yields of the corresponding R2P-o-C6H4CN products. 相似文献
949.
Haeffner F Jacobson MA Keresztes I Williard PG 《Journal of the American Chemical Society》2004,126(51):17032-17039
A density functional theory (B3LYP/6-31+G) study was undertaken in an effort to learn more about the mechanisms controlling the regioselective deprotonations of the synthetically versatile N-lithio-N-(tert-butyl)allylamide 1 and N-lithio-N-(trimethylsilyl)allylamine 2 compounds. The calculations suggest that deprotonation of 1 occurs exclusively at the allylic position. This agrees with experimental results. The calculations also suggest that deprotonation of allylamine 2 exclusively at the cis-vinylic position is due to kinetic control. 相似文献
950.
Jan Mrázek Vlastimil Matejec Ivan Kasik Milos Hayer Daniela Berková 《Journal of Sol-Gel Science and Technology》2004,31(1-3):175-178
This paper presents results on using the sol-gel process for the preparation of microstructure fibers (MSFs). In this preparation the sol-gel method is used for the formation of bonds between silica tubes and silica rods in the input stacks for MSF drawing and for filling-in the interstices between these parts. Gels applied on the stacks were prepared from sols composed of tetraethoxysilane, phosphorous oxychloride, boron tribromide, ethanol, HCl and water. Pastes prepared from the sols and solid fabricated through heat treatment of the sols at 1000°C were also used. The sols were applied on the stacks by the dip-coating method and the pastes were applied manually. The formed xerogels were heat-treated at temperatures of up to 1000°C. The MSFs of the grapefruit type were drawn from the stacks at a temperature of about 1900°C. Waveguiding properties of the fibers were examined under their excitation by an inclined collimated beam. It has been found that the sol-gel method is suitable particularly for filling-in the interstices at the end of the stack, which enables pressure control inside holes of the stack during MSF drawing. 相似文献