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71.
W Thormann A Minger S Molteni J Caslavska P Gebauer 《Journal of chromatography. A》1992,593(1-2):275-288
Many substituted purines (theobromine, caffeine, paraxanthine, theophylline and uric acid, as well as other methylated xanthines and uric acids) can easily be separated and analysed in one run using micellar electrokinetic capillary chromatography with a boratephosphate buffer containing 75 mM sodium dodecyl sulphate (pH approximately 9). Serum, saliva and urine samples collected after the self-administration of caffeine and serum samples from patients receiving theophylline or caffeine pharmacotherapy were screened for substituted purines. The data presented show the ease of using on-column multi-wavelength detection for investigating the feasibility of direct sample application, the characterization of sample pretreatment procedures and peak confirmation by comparing absorption spectra. It is shown that the determination of purines in serum and saliva samples, including therapeutic concentrations of caffeine and theophylline, can be accomplished without any sample pretreatment, whereas sample extraction is required for the determination of purines in urine. Quantitative data for the determination of micromolar amounts of theophylline (samples from adult patients) and caffeine (samples from infants born prematurely) in serum samples compared well with data obtained by non-isotopic immunoassays. Micellar electrokinetic capillary chromatography with the direct injection of serum or saliva samples requires only microlitre volumes of sample and several different compounds can be determined within a few minutes. 相似文献
72.
Procedures are presented for the purification of the subunit dimer from Acanthochiton fasicularis hemocyanin. Electron microscopy of negatively stained specimens revealed a uniform population of macromolecules possessing the characteristic "boat shape". A 3D reconstruction from this EM data generated a approximately 3 nm resolution model that correlates well with earlier data of the purported subunit dimer, extracted from the 3D reconstruction of the didecamer of Haliotis tuberculata hemocyanin type 1. 相似文献
73.
I. Peter W. von Oertzen S. Thummerer H.G. Bohlen B. Gebauer J. Gerl M. Kaspar I. Kozhoukharov T. Kröll M. Rejmund H.J. Wollersheim I.J. Thompson 《The European Physical Journal A - Hadrons and Nuclei》2003,16(4):509-525
At energies below the Coulomb barrier, neutron transfer and Coulomb excitation have been measured in a very heavy asymmetric
nuclear system, in 206Pb + 118Sn. These are semi-magic nuclei showing super-fluid properties. Particle-γ coincidence techniques using 5 Euroball Cluster
detectors (EB), combined in a set-up with the Heidelberg-Darmstadt NaI Crystal Ball (CB), have been used. Position-sensitive
detectors allowed the observation of scattering processes covering angles from 110 up to 150 degrees. The fragments are identified
via the known γ-decays of the lowest excited states using the high resolution of EB. Using the unique feature of the set-up
with the CB, transfer to well-defined final channels with known quantum numbers is selected using the high-efficiency multiplicity
filter of the CB with no second γ-ray, i.e. without feeding. The data are analysed using the semi-classical approach and transfer probabilities are obtained. Coulomb
excitation has been analysed using known transition probabilities. The enhancement is deduced for the two-neutron transfer
populating the low-lying super-fluid 2+ states in 120Sn and 116Sn, while the 2n transition remains in the ground state for the 20NPb nuclei. Large enhancements up to EF ≃ 103 are observed. This is the first observation of neutron pair transfer enhancement for a heavy nuclear binary system with super-fluid
properties with experimentally separated levels. The calculations with microscopic 2-neutron wave functions, with configuration
mixing over six shell model configurations and using the coupled reaction channels approach, reproduce well the observed probabilities
and the enhancement.
Received: 27 August 2002 / Accepted: 9 December 2002 / Published online: 25 March 2003
RID="a"
ID="a"e-mail: oertzen@hmi.de
Communicated by D. Schwalm 相似文献
74.
非透明材料冲击温度测量是通过对界面光辐射历史的观察实现的 ,因此对界面光辐射历史的研究是非透明材料冲击温度测量的基础。但由于冲击阻抗的失配导致界面上出现波的反射而引起温度的变化与界面热流动产生的温度变化交杂在一起 ,以及过程的瞬时性 ,使得对这一过程的实验研究显得非常困难。设计了一种界面波阻抗近似相同的特殊实验装置 ,用光辐射测量技术研究了在冲击压缩下CHBr3/NaCl界面的热弛豫过程。实验结果和理论分析表明CHBr3/NaCl界面的热弛豫时间在纳秒量级 ,与Grover等人的理论预估一致。 相似文献
75.
K. Sekiguchi H. Okamura Y. Wada J. Miyazaki T. Taguchi U. Gebauer M. Dozono S. Kawase Y. Kubota C. S. Lee Y. Maeda T. Mashiko K. Miki S. Sakaguchi H. Sakai N. Sakamoto M. Sasano Y. Shimizu K. Takahashi R. Tang T. Uesaka T. Wakasa K. Yako 《Physics of Particles and Nuclei》2014,45(1):190-192
With the aim of clarifying roles of the 3NFs in nuclei experimental programs with polarized deuterons beams at intermediate energies are in progress at RIKEN RI Beam Factory. As the first step, we have measured a complete set of deuteron analyzing powers (iT 11, T 20, T 21, T 22) in deuteron-proton elastic scattering at 250 and 294 MeV/nucleon. The obtained data are compared with the Faddeev calculations based on the modern nucleon-nucleon forces together with the Tucson-Melbourne’99, and UrbanaIX three nucleon forces. 相似文献
76.
Malcıoğlu OB Calzolari A Gebauer R Varsano D Baroni S 《Journal of the American Chemical Society》2011,133(39):15425-15433
The optical properties of the flavylium state of the cyanin dye are simulated numerically by combining Car-Parrinello molecular dynamics and linear-response time-dependent density functional theory calculations. The spectrum of the dye calculated in the gas phase is characterized by two peaks in the yellow and in the blue (green and violet), using a GGA-PBE (hybrid-B3LYP) DFT functional, which would bring about a greenish (bright orange) color incompatible with the dark purple hue observed in nature. Describing the effect of the water solvent through a polarizable continuum model does not modify qualitatively the resulting picture. An explicit simulation of both solvent and thermal effects using ab initio molecular dynamics results instead in a spectrum that is compatible with the observed coloration. This result is analyzed in terms of the spectroscopic effects of the molecular distortions induced by thermal fluctuations. 相似文献
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