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141.
High-performance liquid chromatography is employed to determine the contents of six marker components such as mangiferin, jateorrhizine, palmatine, berberine, cinnamic acid, and cinnamaldehyde in the traditional Chinese medicinal preparation Zi-Shen pill. The separation is performed on a C(18) column by stepwise gradient elution with water (0.2%, v/v, triethylamine adjusted to pH 4 with phosphoric acid)-methanol-acetonitrile (0.01 min, 98:0:2; 20 min, 80:5:15; 30 min, 65:13:22; and 55 min, 65:13:22) as the mobile phase at a flow rate of 0.9 mL/min, with UV detection at 280 nm. Six regression equations show good linear relationships between the peak area of each marker and concentration. The recoveries of the markers listed are 95.5%, 98.3%, 96.8%, 99.5%, 101.7%, and 102.1%, respectively. The repeatability and reproducibility (relative standard deviation) of the method are less than 2.5% and 3.3%, respectively. 相似文献
142.
Firat AK Karakaş HM Yakinci C Altinok T Alkan A Biçak U 《Magnetic resonance imaging》2004,22(9):1329-1332
Acute disseminated encephalomyelitis (ADEM) is an immune-mediated demyelinating disorder usually encountered in children or adolescents and characterized by multifocal neurological deficits of rapid onset. Typical target areas of demyelination include the corona radiata, centrum semiovale, periventricular white matter, cerebellar peduncles and brainstem. Involvement of deep gray matter nuclei is also frequent. We report a 6-year-old boy with ADEM who had only brainstem involvement. Serial magnetic resonance images representing the stage of disease and response to steroid treatment are presented. 相似文献
143.
E.?BiémontEmail author P.-H.?Lefèbvre P.?Quinet S.?Svanberg H.?L.?Xu 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,27(1):33-41
New radiative lifetimes for 20 levels of Pr II have been measured using the time-resolved laser-induced fluorescence (LIF) technique. The combination of these experimental values with theoretical branching fractions (BF) obtained with the pseudo-relativistic Hartree-Fock (HFR) approach has allowed us to determine oscillator strengths and transition probabilities for about 150 lines appearing in the spectral region between 369.9 and 741.2 nm. A detailed discussion of our new results and comparisons with previous data are also given in the present paper.Received: 26 March 2003, Published online: 29 July 2003PACS:
32.70.Cs Oscillator strengths, lifetimes, transition moments - 42.62.Fi Laser spectroscopy 相似文献
144.
In this paper, we consider the oscillation of the second-order neutral difference equation $$\Delta ^2 \left( {x_n - px_{n - \tau } } \right) + q_n f\left( {x_{n - \sigma _n } } \right) = 0$$ as well as the oscillatory behavior of the corresponding ordinary difference equation $$\Delta ^2 z_n + q_n f\left( {R\left( {n,\lambda } \right)z_n } \right) = 0$$ . 相似文献
145.
Pei-Hong Gu Xiao-Jun Bi Xinmin Zhang 《The European Physical Journal C - Particles and Fields》2007,50(3):655-659
In this paper we study dynamical CPT-violation in the neutrino sector as induced by the dark energy of the universe. Specifically
we consider a dark energy model where the dark energy scalar derivatively interacts with the right-handed neutrinos. This
type of derivative coupling leads to cosmological CPT-violation during the evolution of the background field of the dark energy.
We calculate the induced CPT-violation of left-handed neutrinos and find that the CPT-violation produced in this way is consistent
with the present experimental limit and sensitive to future neutrino oscillation experiments such as the neutrino factory.
PACS 95.36.+x; 14.60.St 相似文献
146.
The electronic structure and magnetic properties of the Co at the Co/X (X=Co, Cu, V and Ta) interfaces have been studied by first-principle discrete variational method. We have found that the spin asymmetry and the s-electron itinerancy of the Co interface layer in the Co/X systems are strongly dependent on the electronegativity of the non-magnetic layers. A large difference in the electronegativity between the non-magnetic and Co layers is unfavorable both for s-electron itinerancy and for the spin exchange split of DOS at the Fermi level. Further study on charge density has revealed that a bond is formed across the Co/V and Co/Ta interfaces. 相似文献
147.
The general formulas of the network for the power exponents of the degree distribution and the entropy are presented based on an open Liouville equation for the driven network. The proposed harmonious unifying hybrid preferential models (HUHPM) have been studied using the obtained formalism, in which the simulating results are quite consistent with the theoretical results. 相似文献
148.
This paper describes measurements of a vibrating object with rough surface by the time-averaged method of holography using a newly designed optically addressed liquid crystal spatial light modulator with a resolution of 102 lp/mm and a diffraction efficiency of 16%. An object vibrating faster than several tens of Hz could be visualized. The pattern obtained by the method provides the locus of vibrating nodes. The advantage of this method is that a high contrast pattern of a vibrating object can be imaged in near-real-time, although the sensitivity of vibration is decreased. 相似文献
149.
150.
肿瘤抑制蛋白p53的动力学在一定程度上可以决定DNA损伤后的细胞命运.p53的动力学行为与p53信号通路中p53-Mdm2振子模块密切相关.然而,p53的负调控子Mdm2的生成速率的增加使其在一些癌细胞中过表达.因此探讨Mdm2生成速率对p53动力学的影响有重要意义.同时,PDCD5作为p53的激活子也调控p53的表达.因此,本文针对PDCD5调控的p53-Mdm2振子模型,通过分岔分析获得了Mdm2生成速率所调控的p53的单稳态、振荡以及单稳态与振荡共存的动力学行为,且稳定性通过能量面进行了分析.此外,噪声强度对p53动力学的稳定性有重要的影响.因此,针对p53的振荡行为,探讨了噪声强度对势垒高度和周期的影响.本文所获得的结果对理解DNA损伤后的p53信号通路调控起到一定的指导作用. 相似文献