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131.
Armin Junge und K. Mitzopulos 《Fresenius' Journal of Analytical Chemistry》1873,12(1):209-210
Ohne Zusammenfassung 相似文献
132.
133.
Nianjun Yang Rene Hoffmann Waldemar Smirnov Armin Kriele Christoph E. Nebel 《Electrochemistry communications》2010,12(9):1218-1221
Nanotextured diamond surfaces with geometrical properties close to protein dimensions were used for the realization of direct electron transfer of cytochrome c (cyt c) without any covalent bonding. The peroxidase activity of native and denatured cyt c was also investigated. Cyclic voltammograms of native cyt c show quasi-reversible electron transfer reactions, while no heme redox activity is detected for denatured cyt c. Unfolding (denaturation) of cyt c can be achieved in the presence of hydrogen peroxide. Partially or fully denatured cyt c showed higher peroxidase activity than native cyt c. This is because denatured cyt c loses its tertiary structure and hydrogen peroxide is easier to access the heme redox center. The apparent Michaelis–Menten constant Km for native and denatured cyt c has been determined to be 0.23 mM and 0.08 mM. 相似文献
134.
Philipp AA Wissenbach DK Weber AA Zapp J Maurer HH 《Journal of mass spectrometry : JMS》2010,45(11):1344-1357
Mitragyna speciosa (Kratom in Thai), a Thai medical plant, is misused as herbal drug of abuse. Besides the most abundant alkaloids mitragynine (MG) and paynantheine (PAY), several other alkaloids were isolated from Kratom leaves, among them the third abundant alkaloid is speciogynine (SG), a diastereomer of MG. The aim of this present study was to identify the phase I and II metabolites of SG in rat urine after the administration of a rather high dose of the pure alkaloid and then to confirm these findings using human urine samples after Kratom use. The applied liquid chromatography coupled to low- and high-resolution mass spectrometry (LC-HRMS-MS) provided detailed information on the structure in the MS(n) mode particularly with high resolution. For the analysis of the human samples, the LC separation had to be improved markedly allowing the separation of SG and its metabolites from its diastereomer MG and its metabolites. In analogy to MG, besides SG, nine phase I and eight phase II metabolites could be identified in rat urine, but only three phase I and five phase II metabolites in human urine. These differences may be caused by the lower SG dose applied by the user of Kratom preparations. SG and its metabolites could be differentiated in the human samples from the diastereomeric MG and its metabolites comparing the different retention times determined after application of the single alkaloids to rats. In addition, some differences in MS(2) and/or MS(3) spectra of the corresponding diastereomers were observed. 相似文献
135.
Heqing Jiang Dr. Fangyi Liang Oliver Czuprat Konstantin Efimov Armin Feldhoff Dr. Steffen Schirrmeister Dr. Thomas Schiestel Dr. Haihui Wang Prof. Jürgen Caro Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(26):7898-7903
A porous perovskite BaCoxFeyZr0.9?x?yPd0.1O3?δ (BCFZ‐Pd) coating was deposited onto the outer surface of a BaCoxFeyZr1?x?yO3?δ (BCFZ) perovskite hollow‐fiber membrane. The surface morphology of the modified BCFZ fiber was characterized by scanning electron microscopy (SEM), indicating the formation of a BCFZ‐Pd porous layer on the outer surface of a dense BCFZ hollow‐fiber membrane. The oxygen permeation flux of the BCFZ membrane with a BCFZ‐Pd porous layer increased 3.5 times more than that of the blank BCFZ membrane when feeding reactive CH4 onto the permeation side of the membrane. The blank BCFZ membrane and surface‐modified BCFZ membrane were used as reactors to shift the equilibrium of thermal water dissociation for hydrogen production because they allow the selective removal of the produced oxygen from the water dissociation system. It was found that the hydrogen production rate increased from 0.7 to 2.1 mL H2 min?1 cm?2 at 950 °C after depositing a BCFZ‐Pd porous layer onto the BCFZ membrane. 相似文献
136.
We present a unique combination of the numerical three-dimensional (3D) reconstruction of the shape of an object with interferometric deformation measurements. Two cameras record several holograms of an object that is illuminated by structured illumination. This illumination is realized by speckle patterns. To improve the image quality, an inplace speckle reduction technique is combined with the structured illumination to reduce the effect of disturbing subjective speckles which appear in the reconstructed images. Stereophotogrammetric methods are applied to extract the 3D surface information of the object out of the reconstructed images. Since the recording is done by holography and because stereophotogrammetry enables a pointwise correlation between the two views, it is possible to combine other holographic techniques with the reconstructed 3D shape. This is demonstrated by an interferometric deformation measurement of an object cooling down. The resulting interferometric fringes are mapped onto the reconstructed 3D surface. Hence, the proposed method enables automatic and dense matching of interferometric fringe-maps recorded by spatially separated holograms onto the surface of the object, which has not yet been realized by existing techniques. 相似文献
137.
On spurious and corrupted multifractality: The effects of additive noise, short-term memory and periodic trends 总被引:1,自引:0,他引:1
Josef LudescherMikhail I. Bogachev Jan W. KantelhardtAicko Y. Schumann Armin Bunde 《Physica A》2011,390(13):2480-2490
We study the performance of multifractal detrended fluctuation analysis (MF-DFA) applied to long-term correlated and multifractal data records in the presence of additive white noise, short-term memory and periodicities. Such additions and disturbances that can be typically found in the observational records of various complex systems ranging from climate dynamics to physiology, network traffic, and finance. In monofractal records, we find that (i) additive white noise hardly results in spurious multifractality, but causes underestimated generalized Hurst exponents h(q) for all q values; (ii) short-range correlations lead to pronounced crossovers in the generalized fluctuation functions Fq(s) at positions that decrease with increasing moment q, thus causing significantly overestimated h(q) for small q and spurious multifractality; (iii) periodicities like seasonal trends (with standard deviations comparable with the one of the studied process) result in spurious “reversed” multifractality where h(q) increases with increasing q (except for very short time windows). We also show that in multifractal cascades moderate additions of noise, short-range memory, or periodic trends cause flawed results for h(q) with q<2, while h(q) with q>2 remains nearly unchanged. 相似文献
138.
In this paper, we are concerned with the multiplicity of solutions for a fourth-order impulsive differential equation with Dirichlet boundary conditions and two control parameters. Using variational methods and a three critical points theorem, we give some new criteria to guarantee that the impulsive problem has at least three classical solutions. We also provide an example in order to illustrate the main abstract results of this paper. 相似文献
139.
An automotive suspension system represents one of the most complex and important systems in a passenger vehicle, which has to ensure a robust and optimized contact between the wheels and the road at any time. For improving a suspension system it is important to take an investigative look at the interaction between suspension, tire and road dynamics. Thus a part of a study into aspects of suspension modeling on multi-body simulations of rear multi-link suspension system dynamics with focus on the tire footprint area is presented in this work. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
140.
Stefan G. Ebbinghaus Anke Weidenkaff Anita Rachel Armin Reller 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(9):i91-i93
The structure of strontium niobium dioxygen nitride, SrNbO2N, has been solved by powder neutron diffraction at room temperature and 1.5 K. SrNbO2N crystallizes in the tetragonal space group I4/mcm, with a = 5.7056 (4) and c = 8.1002 (9) Å at room temperature, and a = 5.6938 (4) and c = 8.0974 (8) Å at 1.5 K. The crystal structure is derived from the cubic perovskite archetype by a slight rotation of the Nb(O,N)6 octahedra with respect to the tetragonal axis. A partially ordered distribution of oxygen and nitrogen on the anionic sites was found. 相似文献