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961.
Lana G. Kaiser Ma?gorzata Marjańska Gerald B. Matson Isabelle Iltis Seth D. Bush Brian J. Soher Susanne Mueller Karl Young 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2010,202(2):259-266
Glutathione (GSH) is a powerful antioxidant found inside different kinds of cells, including those of the central nervous system. Detection of GSH in the human brain using 1H MR spectroscopy is hindered by low concentration and spectral overlap with other metabolites. Previous MRS methods focused mainly on the detection of the cysteine residue (GSH-Cys) via editing schemes. This study focuses on the detection of the glycine residue (GSH-Gly), which is overlapped by glutamate and glutamine (Glx) under physiological pH and temperature. The first goal of the study was to obtain the spectral parameters for characterization of the GSH-Gly signal under physiological conditions. The second goal was to investigate a new method of separating GSH-Gly from Glx in vivo. The characterization of the signal was carried out by utilization of numerical simulations as well as experiments over a wide range of magnetic fields (4.0–14 T). The proposed separation scheme utilizes J-difference editing to quantify the Glx contribution to separate it from the GSH-Gly signal. The presented method retains 100% of the GSH-Gly signal. The overall increase in signal to noise ratio of the targeted resonance is calculated to yield a significant SNR improvement compared to previously used methods that target GSH-Cys residue. This allows shorter acquisition times for in vivo human clinical studies. 相似文献
962.
Satoshi Someya Satoshi Yoshida Koji Okamoto Yan Rong Li Manabu Tange Mohammad Mezbah Uddin 《显形杂志》2010,13(1):41-47
Abstract
Droplets impinging on a hot surface that is near the Leidenfrost temperature were experimentally investigated. Ejection of jets from the top of the droplet was observed during the transient interaction between the droplet and a hot wall. We term this phenomenon jet ejection from droplets. When the bottom of the droplet initially impacts the hot surface, a jet is to be ejected from the top of the droplet. The jet ejection occurred only at low impact velocities and around the wetting limit temperature. It was not observed when droplets were dropped from large heights or when the surface was at a high temperature. 相似文献963.
Pomponlike La2(MoO4)3 microstructures assembled with single-crystalline nanoflakes have been facilely fabricated via a surfactant-assisted ultrasound route for the first time. Various synthesis conditions were examined, such as the surfactant concentration, the molecular structure of surfactants, and the pH value. The obtained pomponlike microstructures were characterized by X-ray diffraction (XRD), (field-emission) scanning electron microscopy [(FE)SEM], transmission electron microscopy (TEM), and nitrogen adsorption/desorption isotherms. It has been revealed that a minimum concentration of sodium dodecylsulfate (SDS) was required for the formation of pomponlike La2(MoO4)3 microstructures. When the SDS concentration is above 0.02 mol L−1, the pomponlike microstructures become more perfect, and the size is also increased with the increasing SDS concentration. Under the same sonication, similar pomponlike microstructures were obtained when a cationic surfactant, cetyltrimethyl ammonium bromide (CTAB), was used instead of the anionic surfactant SDS, indicating that the hydrophobic alkyl chains are an important factor for the formation of the pomponlike La2(MoO4)3 microstructures. It is also found that the pomponlike La2(MoO4)3 microstructures can only be obtained within an optimal pH range of 8.0–9.0 under sonication. Based on TEM, Fourier transform infrared spectroscopy (FT-IR) and solubilization experiment, a formation mechanism of pomponlike La2(MoO4)3 microstructures was proposed, in which the collaborative action of surfactants and sonication plays a key role. Furthermore, the porosity of the pomponlike La2(MoO4)3 microstructures were discussed. 相似文献
964.
X. G. Liu D. Y. Geng J. J. Jiang B. Li S. Ma D. Li W. Liu Z. D. Zhang 《Journal of nanoparticle research》2010,12(4):1167-1172
The HoCo2 nanoparticles are found to be stable in air without any shell protection. The HoCo2 nanoparticles display superparamagnetic properties between their blocking temperature of 40 K and Curie temperature of 78 K.
The magnetic-entropy change increases with decreasing temperature at a certain magnetic-field change, which is ascribed to
the competition between the Zeeman energy and thermal-agitation energy at low temperatures. A large magnetic-entropy change
of 19.4 J kg−1 K−1 was found at 7.5 K in an applied-field change from 1 to 7 T, while 6.1 J kg−1 K−1 was achieved in a low field change of 1 T. HoCo2 nanoparticles are useful for application of magnetic refrigeration at low temperatures. 相似文献
965.
<正>We present a novel method for realizing double-image encryption algorithm by combining the images in different transform domains.Two original images are encrypted into two interim images by fractional Fourier transform and gyrator transform,respectively.The two encrypted images can be obtained by means of the addition and subtraction of the two interim images.This is defined as a double-image sharing scheme,in which the original images are encrypted into two parts.The original images cannot be recovered only with any one of the two interim images.Numerical simulation experiments demonstrate the validity of the algorithm. 相似文献
966.
K. Esquivel Ma. G. García J. F. J. Rodríguez M. Vega González L. Escobar-Alarcón Luis Ortiz-Frade Luis A. Godínez 《Journal of nanoparticle research》2011,13(8):3313-3325
This study presents the synthesis of TiO2 doped with different amounts of Co and Ni, starting from a simple metallic titanium powder. A successful electrophoretic
deposition of these materials on ITO electrodes was achieved for its potential application as photoanodes. EDX, diffuse reflectance
UV–Vis spectroscopy, and XRD measurements gave information on the chemical composition of the material and the location of
the Ni or Co within the crystal structure of TiO2. Raman spectroscopy suggests that for a higher content of doping metal above a defined percentage, the formation of metal
oxide is promoted. A preliminary study of photoelectrocatalytic orange dye degradation shows higher color removal efficiency
as compared to the commercial TiO2 material. 相似文献
967.
968.
用流变震荡模式研究了10 wt%浓度的弹道明胶在冷却和等温下的老化行为.对明胶从sol-gel点冷却到某个目标温度的过程,通过不同冷却速率的实验,建了一个弹性模量与温度的线性关系.不同温度下明胶的等温老化实验表明,弹性模量-时间曲线具有相似的形状.依据Normand提出的二级反应动力学模型,引入一个表征明胶老化行为的速率常数,构建了一个预测弹道明胶在老化初级阶段的弹性模量演化的模型.该模型中模量-温度关系在初始和无穷大时是直线,其他模量-温度线是近似直线,并交于sol-gel点.老化速率常数和过冷度之间符合Flory-Weaver方程.对弹性模量和老化时间进行归一化处理,可将不同温度下的老化曲线叠加成一条主曲线. 相似文献
969.
Soft set theory based on its extension 总被引:2,自引:0,他引:2
In this paper, we point out a defect that the definitions of soft subset and soft intersection in Maji’s paper are partial
definitions, and then we introduce extension of soft set to redefine and simplify operations between soft sets. At last, we
obtain some algebraic properties of new soft operations. 相似文献
970.