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71.
A localized surface plasmon resonance based immunosensor for the detection of casein in milk 总被引:2,自引:0,他引:2
Ha Minh Hiep Kagan Kerman Do-Kyun Kim Yuzuru Takamura 《Science and Technology of Advanced Materials》2007,8(4):331-338
In this research, a localized surface plasmon resonance (LSPR) immunosensor based on gold-capped nanoparticle substrate for detecting casein, one of the most potent allergens in milk, was developed. The fabrication of the gold-capped nanoparticle substrate involved a surface-modified silica nanoparticle layer (core) on the slide glass substrate between bottom and top gold layers (shell). The absorbance peak of the gold-capped nanoparticle substrate was observed at ∼520 nm. In addition, the atomic force microscopy (AFM) images demonstrated that the nanoparticles formed a monolayer on the slide glass. After immobilizing anti-casein antibody on the surface, our device, casein immunosensor, could be applied easily for the detection of casein in the raw milk sample without a difficult pretreatment. Under the optimum conditions, the detection limit of the casein immunosensor was determined as 10 ng/mL. Our device brings several advantages to the existing LSPR-based biosensors with its easy fabrication, simple handling, low-cost, and high sensitivity. 相似文献
72.
Evaggelia D. Tzika Vassiliki Papadimitriou Theodore G. Sotiroudis Aristotelis Xenakis 《European Journal of Lipid Science and Technology》2008,110(2):149-157
The autoxidation at alkaline pH and enzymatic oxidation by mushroom tyrosinase of oleuropein, the dominant biophenol present in the fruits and leaves of Olea europea, was followed by both electron paramagnetic resonance (EPR) and absorption spectroscopy. For comparison, the same oxidation processes were applied to 4‐methylcatechol, a simple polyphenol present in olive mill wastewaters. EPR spectra of stable o‐semiquinone radicals produced during autoxidation at pH 12 and short‐lived o‐semiquinone free radicals produced during autoxidation at pH 9.0 or tyrosinase action and stabilized by chelation with a diamagnetic metal ion (Mg2+) were recorded for both polyphenols, and the corresponding hyperfine splitting constants were determined. The UV‐Vis spectral characteristics of the oxidation of polyphenols were highly dependent on the type of polyphenol, oxidant type and the pH of the reaction. The kinetic behavior of tyrosinase in the presence of oleuropein and 4‐methylcatechol was followed by recording spectral changes at 400 nm (absorption maximum) over time. The tysosinase activity with oleuropein showed a pronounced pH optimum at pH 6.5 and a minor one around pH 8. From the data analysis of the initial rate at pH 6.5, the kinetic parameters Km = 0.34 ± 0.03 mM and Vmax = 0.029 ± 0.002 ΔA400 min–1 were determined for oleuropein. 相似文献
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激光与DNA作用系统的随机共振研究 总被引:6,自引:2,他引:4
建立了激光与DNA分子系统相互作用的Fokker-Planck方程,通过对该方程的数值研究,发现在绝热近似下,系统发生随机共振,噪声强度,激光振幅和频率协同作用共同制约着生物系统的演化过程,噪声强度在生物系统遗传变异过程中可能起重要作用。 相似文献
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Visually perceiving an action may activate corresponding motor programs. This automatic motor activation can occur both for higher level (i.e., the goal of an action) and for lower level (i.e., the specific effector with which it is executed) aspects of an action. The authors used a tool-use action paradigm to experimentally dissociate priming effects for observing the target, the movement, or the target-to-movement mapping of a tool-use action. In 3 experiments, participants took turns in acting, observing the tool-use action of another person in trial n-1, and executing an action in trial n. Trial transitions from n-1 to n were manipulated in 4 conditions with (a) mapping repeated and movement and target changed, (b) target repeated and movement and mapping changed, (c) movement repeated and target and mapping changed, or (d) all components repeated. Results indicate priming effects for repeating the target-to-movement mapping (i.e., the action rule) of a tool-use action and suggest that a rather abstract action schema is activated during action observation. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
79.
Nemai Chandra Karmakar 《国际射频与微波计算机辅助工程杂志》2007,17(3):311-319
The resonant frequency of a circular patch antenna with and without circular cavity is measured. The patch miniaturization in the presence of the cavity is proved. Different methods of reducing resonant frequencies and broadening bandwidth without significantly reducing antenna gain are presented. Capacitively loaded patch and slits on the patch stimulate the patch at lower frequencies and multiple resonances, thus help miniaturization. Finally ferrite loading on the feed probe further increases the bandwidth without significantly reducing the antenna gain. The method is much more improved than that for a resistive loaded patch and a deformed patch. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007. 相似文献
80.
The structural change of diamond induced by hydrogen plasma exposure at room temperature, and its thermal stability, were investigated using electron spin resonance (ESR), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) techniques. ESR observation revealed that it gave rise to a highly defective structure (spin concentration of 1020 cm− 3), which is very similar to the structure of hydrogenated amorphous carbon (a-C : H) confirmed by XPS and FTIR. Post-annealing was also carried out to clarify the thermal stability of the defects. The number of spin centers decreased with increasing annealing temperature, and eventually, the defective structure changed to a graphitic one by annealing at 800 °C. 相似文献