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111.
Rimma Lapovok Emil Zolotoyabko Alex Berner Yaron Kauffmann Eugene Lakin Natalya Larianovsky 《哲学杂志》2016,96(11):1022-1046
An effect of alloying element content on mechanical properties and precipitate formation in Mg–RE alloys was studied for Mg–8Gd–4Y–1Zn–0.4Zr (wt%) and Mg–10Gd–5Y–1.8Zn–0.4Zr (wt%). It is shown that small variations in the alloying element concentration can be used to manipulate the alloy microstructure and precipitate formation towards eliminating the asymmetry (tension/compression) and anisotropy of yield stress. 相似文献
112.
Natalya V. Kirij Yurii L. Yagupolskii Wieland Tyrra Dr. Ingo Pantenburg Dieter Naumann Prof. Dr. 《无机化学与普通化学杂志》2007,633(7):943-945
represents the first structurally characterized example of a trifluoromethyl main group element compound with more than 8‐N (where N is the main group number) perfluoroalkyl groups and also the first fluoro(triorgano)tellurium derivative. Its polymeric nature is caused by asymmetric bridging fluorine atoms forming infinite chains. 相似文献
113.
Rosenblum G Meroueh S Toth M Fisher JF Fridman R Mobashery S Sagi I 《Journal of the American Chemical Society》2007,129(44):13566-13574
Activation of matrix metalloproteinase zymogen (pro-MMP) is a vital homeostatic process, yet its molecular basis remains unresolved. Using stopped-flow X-ray spectroscopy of the active site zinc ion, we determined the temporal sequence of pro-MMP-9 activation catalyzed by tissue kallikrein protease in milliseconds to several minutes. The identity of three intermediates seen by X-ray spectroscopy was corroborated by molecular dynamics simulations and quantum mechanics/molecular mechanics calculations. The cysteine-zinc interaction that maintains enzyme latency is disrupted via active-site proton transfers that mediate transient metal-protein coordination events and eventual binding of water. Unexpectedly, these events ensue as a direct result of complexation of pro-MMP-9 and kallikrein and occur before proteolysis and eventual dissociation of the pro-peptide from the catalytic site. Here we demonstrate the synergism among long-range protein conformational transitions, local structural rearrangements, and fine atomic events in the process of zymogen activation. 相似文献
114.
Hessenauer-Ilicheva N Franke A Meyer D Woggon WD van Eldik R 《Journal of the American Chemical Society》2007,129(41):12473-12479
The use of synthetic iron(III) porphyrins as models for heme-type catalysts in biomimetic cytochrome P450 research has provided valuable information on the nature and reactivity of intermediates produced in the "peroxide shunt" pathway. This article reports spectroscopic detection of reactive intermediates formed in the epoxidation reaction of cis-stilbene with m-chloroperoxybenzoic acid catalyzed by a new mimic of cytochrome P450 with a substituted RSO3- group (1). The application of low-temperature rapid-scan stopped-flow techniques enabled the determination of equilibrium and rate constants for the formation and decay of all intermediates in the catalytic cycle of 1, including the rate constant for the formation (1*+)FeIV=O and for oxygen transfer to the substrate. Noteworthy, the reaction of (1*+)FeIV=O with cis-stilbene leads to an almost complete re-formation (95%) of the starting complex 1. The results show that complex 1 is a valuable catalyst with promising properties for further applications in a biomimetic approach toward mimicking oxygenation reactions of cytochrome P450. 相似文献
115.
Belova NV Oberhammer H Girichev GV Shlykov SA 《The journal of physical chemistry. A》2007,111(11):2248-2252
The geometric structure of malonamide, NH2C(O)-CH2-C(O)NH2, has been investigated by gas electron diffraction (GED) and quantum chemical calculations (B3LYP and MP2 approximations with 6-311++G(3df,pd) basis sets). Both GED and quantum chemistry result in the existence of a single diketo conformer in the gas phase. According to GED refinement this conformer possesses (sc,ac) conformation with one C=O bond in synclinal orientation (dihedral angle tau(O=C-C-C)=49.0(3.0) degrees) and the other C=O bond in anticlinal orientation (dihedral angle tau(O=C-C-C)=139.5(3.3) degrees). The experimental geometric parameters are reproduced very closely by the B3LYP method. 相似文献
116.
Natalya V. Likhanova Rafael Martínez‐Palou M. Aurora Veloz Diana J. Matías Victor E. Reyes‐Cruz Herbert Höpfl Octavio Olivares 《Journal of heterocyclic chemistry》2007,44(1):145-153
117.
Natalya A. Maslennikova Elena A. Golysheva Sergei A. Dzuba 《Molecules (Basel, Switzerland)》2021,26(19)
Intrinsically disordered proteins (IDPs) are proteins that possess large unstructured regions. Their importance is increasingly recognized in biology but their characterization remains a challenging task. We employed field swept Electron Spin Echoes in pulsed EPR to investigate low-temperature stochastic molecular librations in a spin-labeled IDP, casein (the main protein of milk). For comparison, a spin-labeled globular protein, hen egg white lysozyme, is also investigated. For casein these motions were found to start at 100 K while for lysozyme only above 130 K, which was ascribed to a denser and more ordered molecular packing in lysozyme. However, above 120 K, the motions in casein were found to depend on temperature much slower than those in lysozyme. This abrupt change in casein was assigned to an ordering transition in which peptide residues rearrange making the molecular packing more rigid and/or more cohesive. The found features of molecular motions in these two proteins turned out to be very similar to those known for gel-phase lipid bilayers composed of conformationally ordered and conformationally disordered lipids. This analogy with a simpler molecular system may appear helpful for elucidation properties of molecular packing in IDPs. 相似文献
118.
Nicola Maggiarosa Wieland Tyrra Dieter Naumann Natalya V. Kirij Yurij L. Yagupolskii 《Angewandte Chemie (International ed. in English)》1999,38(15):2252-2253
The long-postulated reactive intermediates of polar fluoride-inititated trifluoromethylations with Me3SiCF3 (see scheme) were identified by NMR spectroscopy as [Me3Si(CF3)F]− and [Me3Si(CF3)2]−. 相似文献
119.
A model of a two-sublattice collinear ferrimagnet with direct exchange interaction and unequal values of the partial magnetization has been investigated. The condition of existence of the compensation point is determined from material parameters of the system at low temperatures. The excitation spectra are obtained. An analysis is made of the spectra as a function of the total magnetization of the two sublattices. 相似文献
120.
Anastasia Menshikova Tatiana Evseeva Natalya Shevchenko Boris Shabsels Alexander Yakimansky Sergey Ivanchev 《Macromolecular Symposia》2009,281(1):61-68
Sammary: Various techniques of one-step batch emulsion copolymerization of methyl methacrylate (MMA) or styrene (St) with N-vinylformamide (NVF) initiated by 2,2′-azobis(2-methylpropanamidine) (AIBA) or 2,2′-azobis[4,5-dihydroimidazol-2-yl] (AIP) dihydrochlorides in the presence of dextran, cetyltrimethylammonium bromide (CTAB) or without any stabilizers were examined to obtain monodisperse submicron and nano- particles, having both positive surface charge and hydrophilic surface. After hydrolysis in acidic media, the particle surface contained amino groups originating from NVF units along with carboxylic groups from hydrolyzed initiator residues. The obtained particles were tested as building blocks of hierarchic structures. Owing to their amphiphilic surface, the particles were capable of self-assembling from their dispersions into three-dimentional (3D) ordered arrays. 相似文献