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排序方式: 共有197条查询结果,搜索用时 15 毫秒
1.
Reinhard Oertel Norman Arenz Sten Gunnar Zeitz Jörg Pietsch 《Biomedical chromatography : BMC》2015,29(8):1290-1296
With screening methods in the legal medicine drugs were often detected in autopsy material. In this study the antiarrhythmic and the local anesthetic drug lidocaine could be proved in fifty‐one cases and determined in different autopsy materials. For the first time the comparison of so many distribution patterns of lidocaine in human compartments was possible. A liquid‐liquid extraction procedure, a standard addition method and LC/MS/MS were used for analytics. The measured concentrations in blood were in the therapeutic range or lower. The time between lidocaine application and death was given in twenty‐nine cases. These data were very helpful to estimate and interpret the distribution process of lidocaine between application and death. This time exerted a crucial influence on the distribution of lidocaine in the compartments. Most of the intravenous applicated lidocaine was found in heart blood after a very short time of distribution. Afterwards the highest concentrations were measured in brain. Later the highest concentration was found in the kidney samples or in urine. If the time between lidocaine application and death is known, the results of this study can be used to deepen the knowledge of its pharmacokinetics. If this time is unknown, the circumstances and the causes of death can be better explained. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
2.
In this study, slow strain rate tensile testing at elevated temperature is used to evaluate the influence of temperature and strain rate on deformation behaviour in two different austenitic alloys. One austenitic stainless steel (AISI 316L) and one nickel-base alloy (Alloy 617) have been investigated. Scanning electron microscopy related techniques as electron channelling contrast imaging and electron backscattering diffraction have been used to study the damage and fracture micromechanisms. For both alloys the dominante damage micromechanisms are slip bands and planar slip interacting with grain bounderies or precipitates causing strain concentrations. The dominante fracture micromechanism when using a slow strain rate at elevated temperature, is microcracks at grain bounderies due to grain boundery embrittlement caused by precipitates. The decrease in strain rate seems to have a small influence on dynamic strain ageing at 650°C. 相似文献
3.
4.
The invention of an image system for a boundary value problem adds to a significant understanding of the structure of the problem, both at the mathematical and at the physical level. In this paper, the interior and exterior Neumann functions for the Laplacian in the cases of spherical and ellipsoidal domains are represented in terms of images. Besides isolated images, the presence of the normal derivative in the Neumann condition demands an additional continuous distribution of images, which in the spherical cases, can be restricted to a one‐dimensional manifold, whereas for the ellipsoid, both a one‐dimensional and a two‐dimensional distribution of images is needed. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
5.
Landström J Bergström M Hamark C Ohlson S Widmalm G 《Organic & biomolecular chemistry》2012,10(15):3019-3032
By examining the interactions between the protein hen egg-white lysozyme (HEWL) and commercially available and chemically synthesized carbohydrate ligands using a combination of weak affinity chromatography (WAC), NMR spectroscopy and molecular simulations, we report on new affinity data as well as a detailed binding model for the HEWL protein. The equilibrium dissociation constants of the ligands were obtained by WAC but also by NMR spectroscopy, which agreed well. The structures of two HEWL-disaccharide complexes in solution were deduced by NMR spectroscopy using (1)H saturation transfer difference (STD) effects and transferred (1)H,(1)H-NOESY experiments, relaxation-matrix calculations, molecular docking and molecular dynamics simulations. In solution the two disaccharides β-d-Galp-(1→4)-β-D-GlcpNAc-OMe and β-D-GlcpNAc-(1→4)-β-D-GlcpNAc-OMe bind to the B and C sites of HEWL in a syn-conformation at the glycosidic linkage between the two sugar residues. Intermolecular hydrogen bonding and CH/π-interactions form the basis of the protein-ligand complexes in a way characteristic of carbohydrate-protein interactions. Molecular dynamics simulations with explicit water molecules of both the apo-form of the protein and a ligand-protein complex showed structural change compared to a crystal structure of the protein. The flexibility of HEWL as indicated by a residue-based root-mean-square deviation analysis indicated similarities overall, with some residue specific differences, inter alia, for Arg61 that is situated prior to a flexible loop. The Arg61 flexibility was notably larger in the ligand-complexed form of HEWL. N,N'-Diacetylchitobiose has previously been observed to bind to HEWL at the B and C sites in water solution based on (1)H NMR chemical shift changes in the protein whereas the disaccharide binds at either the B and C sites or the C and D sites in different crystal complexes. The present study thus highlights that protein-ligand complexes may vary notably between the solution and solid states, underscoring the importance of targeting the pertinent binding site(s) for inhibition of protein activity and the advantages of combining different techniques in a screening process. 相似文献
6.
Sten Scheibye Bjarne S. Pedersen S.-O. Lawesson 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-2):271-272
Abstract Recent studies have shown that the dimer of p-methoxyphenylthionophosphinesulfide, 1, is a very superior thiation reagent, as ketones, amides, and esters are in most cases quantitatively converted to their thio-analogues. 相似文献
7.
V. V. Bolotov V. S. Kovivchak A. A. Korepanov E. V. Knyazev S. N. Nesov V. E. Roslikov Yu. A. Sten’kin P. M. Korusenko R. V. Shelagin 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2011,5(6):1185-1188
Layers of por-Si/SnO
x
nanocomposite formed by high-power ion beam irradiation with nanosecond duration have been studied. The results of structural
and elemental analyses of these layers are presented. The high sensitivity of this nanocomposite to low NO2 concentrations at room temperature has been revealed. 相似文献
8.
V. V. Alekseenko D. M. Gromushkin Yu. V. Sten’kin 《Bulletin of the Russian Academy of Sciences: Physics》2011,75(6):857-859
Thermal neutron fluxes were measured using two types of scintillation detectors based on the inorganic scintillator ZnS(Ag):
6LiF+ZnS(Ag) and 10B2O3 + KCl+ZnS(Ag). The preliminary results from these measurements are given. The thermal neutron concentration as a function
of altitude above sea level was determined. The measurements were performed at three locations: in Moscow, at the Baksan Neutrino
Observatory of the Russian Academy of Sciences, and at the Gran Sasso National Laboratory. Variations of neutron count rates
associated with lunar cycles were observed at the remote laboratories. 相似文献
9.
V. V. Bolotov N. A. Davletkil’deev A. A. Korotenko V. E. Roslikov Yu. A. Sten’kin 《Technical Physics》2011,56(11):1593-1598
The layer-by-layer distribution of components in a porous silicon-tin oxide nanocomposite produced by the following three
methods is studied by spectroscopic ellipsometry: chemical vapor deposition, atomic layer deposition, and magnetron sputtering.
It is shown that, in the nanocomposites fabricated by these methods, SnO
x
penetrates to a depth more than 400 nm and is nonuniformly distributed over the porous layer thickness. The nanocomposite
prepared by magnetron sputtering followed by heat treatment has the maximum penetration depth and the maximum uniformity of
layer-by-layer SnO
x
distribution. 相似文献
10.
The random opening and closing of ion channels establishes channel noise, which can be approximated and included into stochastic differential equations (Langevin approach). The Langevin approach is often incorporated to model stochastic ion channel dynamics for systems with a large number of channels. Here, we introduce a discretization procedure of a channel-based Langevin approach to simulate the stochastic channel dynamics with small and intermediate numbers of channels. We show that our Langevin approach with discrete channel open fractions can give a good approximation of the original Markov dynamics even for only 10 K+ channels. We suggest that the better approximation by the discretized Langevin approach originates from the improved representation of events that trigger action potentials. 相似文献