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131.
V. A. Matyshak A. N. Il’ichev O. N. Sil’chenkova V. A. Sadykov V. N. Korchak 《Kinetics and Catalysis》2017,58(2):198-210
It has been demonstrated by quantitative spectrokinetic measurements that, on the surface of zirconia stabilized as a tetragonal phase, the rate-limiting step of the selective catalytic reduction of nitrogen oxides (SCR of NO x ) with propylene is the interaction of surface nitrates with C3H6 yielding organic nitro compounds. It is hypothesized that propylene reacts not with the nitrates themselves but with the activated complex NO2 ads whose structure is intermediate between the structures of the monodentate NO3 ? and NO2 species. Deep C3H6 oxidation exerts an adverse effect on the rate of the SCR of NO x with propylene, and the interaction between O2 and NO, which yields NO2 and NO3 ? stimulates further nitrogen reduction to N2. The effect of the reaction between oxygen and O2N?C n H m on the NO x reduction rate is variable and is determined by the C3H6/NO x ratio. A generalized scheme of the SCR of NO x with propylene on the surface of ZrO2 partially stabilized as a tetragonal phase has been developed by comparing experimental data of this study and data available from the literature. 相似文献
132.
Pone Kamdem Boniface Manju Singh Surjeet Verma Aparna Shukla Feroz Khan Santosh Kumar Srivastava 《Natural product research》2015,29(7):676-680
A simple and reliable high-performance liquid chromatographic method was successfully developed for the study of fingerprint chromatograms of extract and fractions from the leaves of Spathodea campanulata (SC) using verminoside (1) and 1-O-(E)-caffeoyl-β-gentiobiose (2) as marker compounds. Antioxidant activity of SC was determined by using free radical of 2,2-diphenyl-1-picryl-hydrazyl-hydrate as an experimental model. The docking study of selected target, tyrosinase and ligands (ascorbic acid, compounds 1 and 2) was performed through Autodock Vina v0.8. Fingerprints of methanol, chloroform, ethylacetate, n-butanol and water extracts could resolve 13, 11, 22, 16 and 5 peaks, respectively. Extract, fractions and compounds 1 and 2 previously isolated from SC displayed remarkable antioxidant activity with radical-scavenging activity ranging from 2.5 to 6.7 μg/mL. In silico study identified compounds 1 and 2 as potential inhibitors of tyrosinase correlating with the observed antioxidant activity in vitro. 相似文献
133.
A. V. Pashchenko V. P. Pashchenko V. K. Prokopenko Yu. F. Revenko A. S. Mazur V. A. Turchenko V. Ya. Sycheva V. V. Burkhovetskii A. G. Sil’cheva G. G. Levchenko 《Physics of the Solid State》2013,55(3):486-494
Ceramic samples of manganite perovskites La0.6 ? x Pr x Sr0.3Mn1.1O3 (x = 0?0.6) have been studied using the X-ray diffraction, resistive, magnetic (χac, 55Mn NMR), microscopic, and magnetoresistive methods. It has been found that an increase in the praseodymium concentration x leads to a transition from the rhombohedral R $\bar 3$ c (x = 0–0.3) to orthorhombic Pbnm (x = 0.4–0.6) perovskite structure. It has been shown that the real perovskite structure contains anion and cation vacancies, whose concentrations increase with an increase in the praseodymium concentration x. A decrease in the metal-insulator phase transition temperature T mi and the ferromagnetic-paramagnetic phase transition temperature T c with increasing x correlates with an increase in the concentration of vacancies weakening the high-frequency electronic exchange Mn3+ ? Mn4+. For compositions with x = 0 and 0.1, when the lattice contains not only vacancies but also nanostructured clusters with Mn2+ in the A-positions, there is an anomalous hysteresis. An analysis of the asymmetrically broadened 55Mn NMR spectra of the compounds has revealed a high-frequency electronic exchange of the ions Mn3+ Mn4+ in the B-positions and a local heterogeneity of their surrounding by other ions (La2+, Pr3+, Sr2+) and vacancies. The phase diagram has demonstrated that there is a strong correlation between the composition, imperfection of the perovskite structure, phase transition temperatures T mi and T c , and magnetoresistive properties. 相似文献
134.
Resorcin[4]arene-based tetrakis(N-hydantoinylamido)cavitand 1 forms a stable molecular capsule in the presence of suitable anionic guests such as CH(3)OSO(3)(-) or BF(4)(-) in C(2)D(2)Cl(4). Molecular capsule G(2)@1(2) is stabilized by the eight intermolecular imide N-H···O═C hydrogen bondings, two from each four paired hydantoinyl units, and the eight intramolecular amide N-H···O-CH(2)-O hydrogen bondings, four on each two cavitands. The formations of molecular capsules were confirmed by (1)H, 2D NOESY, and 2D-DOSY NMR. 相似文献
135.
Nagarajan A Winter R Eaton-Rye J Burnap R 《Journal of photochemistry and photobiology. B, Biology》2011,104(1-2):212-219
A hybrid approach involving synthetic DNA, fusion PCR, and ectopic expression has been used to genetically manipulate the expression of the D1 protein of photosystem II (PSII) in the model cyanobacterium Synechocystis sp. PCC6803. Due to the toxicity of the full-length psbA gene in E. coli, a chimeric psbA2 gene locus was commercially synthesised and cloned in two halves. High-fidelity fusion PCR utilizing sequence overlap between the two synthetic gene halves allowed the production of a DNA fragment that was able to recombine the full-length psbA2 gene into the Synechocystis chromosome at an ectopic (non-native) location. This was accomplished by designing the synthetic DNA/fusion PCR product to have the psbA2 gene, with control sequences, interposed between chimeric sequences corresponding to an ectopic target chromosomal location. Additionally, a recipient strain of Synechocystis lacking all three psbA genes was produced by a combination of traditional marker replacement and markerless replacement techniques. Transformation of this multiple deletion strain by the synthetic DNA/fusion PCR product faithfully restored D1 expression in terms of its expression and PSII repair capacity. The advantages and potential issues for using this approach to rapidly introduce chimeric sequence characteristics as a general tool to produce novel genetic constructs are discussed. 相似文献
136.
Mallik D Mir A Bhattacharya S Nayar S 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,78(1):332-336
Magnetic iron oxide nanoparticles are inherently biocompatible and are amenable to post synthesis surface modification, making them excellent candidates for many important applications. If the above can be achieved in a single-step i.e., in situ synthesis and functionalization, the results are expected to be more dramatic for sensitive detection of biomolecules. For any application, it is necessary to confer a high level of binding specificity through surface chemistry, which can be introduced by using biological moieties that possess lock-and-key interactions, like those observed in antibody-antigen and enzyme-substrate recognition. In this paper, we have synthesized water based ferrofluids with serum albumin, the major protein component of blood. A series of other ferrofluids using different biocompatible polymers have also been studied with respect to their size determined by transmission electron microscopy, magnetic behavior with the aid of vibrating sample magnetometry and binding capability to bovine serum albumin by quenching of its native fluorescence. From our results, it can be inferred that binding has taken place between magnetic particles and biomolecules, the binding constants of which indirectly reveal the efficiency of the interaction. 相似文献
137.
Manisha R. Bhosle Jyotirling R. Mali Aparna A. Mulay Ramrao A. Mane 《Heteroatom Chemistry》2012,23(2):166-170
An efficient one‐pot three‐component cyclocondensation of 4‐(p‐toulyl sulfonoxy) benzaldehyde, aryl amines, and mercaptoacetic acid in polyethylene glycol 400 (PEG‐400) was conducted to obtain new 2,3‐disubstituted‐4‐thiazolidinones. This route is economical and ecofriendly. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 23:166–170, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20766 相似文献
138.
V. A. Matyshak O. N. Sil’chenkova I. T. Ismailov V. F. Tret’yakov 《Kinetics and Catalysis》2012,53(1):91-100
The main reactions yielding hydrogen are the recombination of hydrogen atoms on copper clusters and methyl formate decomposition.
Methyl formate results from the interaction between the linear methoxy group and the formate complex located on CuO. The source
of CO2 appearing in the gas phase is the formate complex, and the source of CO is methyl formate. The rates of methoxy group conversion
and product formation over supports (ZrO2, CeO2, Ce0.8Zr0.2O2) and copper-containing catalysts (5%Cu/CeO2, 5%Cu/ZrO2, 2%Cu/Ce0.8Zr0.2O2, 2%Cu/Ce0.1Y0.1Zr0.8) are compared. The dominant process in methoxy group conversion over the supports and copper-containing catalysts is methanol
decomposition to H2 and CO and to H2 and CO2, respectively. The methoxy group conversion rate is proportional to the H2 and CO2 formation rate and is determined by the concentration of supported copper. 相似文献
139.
We study a few properties of fermions in an anisotropic harmonic trap in absence as well as in presence of an optical lattice. The density of states (DOS) and specific heat of the fermions are studied for different anisotropies. Analytical expressions for the DOS in a strongly anisotropic harmonic trap are derived. For a particular combined potential, where the fermions are hopping in a 3D lattice under a 2D harmonic potential, the Drude weight of the fermionic system is evaluated. The Drude weight is found to be flat in a wide range of fermion concentrations where it is almost temperature independent. 相似文献
140.
The paper aims to obtain new local/global error bounds for quasi variational inequality problems in terms of the regularized gap function and the D-gap function. These bounds provide effective estimated distances between a specific point and the exact solution of quasi variational inequality problem. 相似文献