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We investigated the late negative components of the contingent negative variations (CNVs) in the verbalization task. Six subjects were instructed to perform three different motor tasks, jaw opening, vocalization of a meaningless sound and that of a word, in response to a sound stimulus following a visual warning stimulus with interstimulus interval of 4.0 sec. The electroencephalograms (EEGs) were recorded from the midline-central (Cz), left and right temporal areas (T3 and T4) and frontal areas (F7 and F8). EEGs were averaged 16 times using the visual stimulus pulse as a trigger to obtain the CNVs in each motor task. There was no significant difference between the tasks of the jaw opening and vocalization of the sound in the CNV amplitudes at bilateral electrodes. However, the amplitudes of the CNVs at the left frontal and temporal areas were significantly larger in the case of vocalization of the word than in that of jaw opening (p < 0.05). On the other hand, there was no significant difference between these two tasks in the CNV amplitudes at the right frontal and temporal areas. Our results suggested that the CNVs generated over the left hemisphere might reflect the brain activities involved in language production. 相似文献
143.
J. Miguel-Snchez A. Guzmn J.M. Ulloa M. Montes A. Hierro E. Muoz 《Microelectronics Journal》2006,37(12):1442-1445
We have grown by Molecular Beam Epitaxy GaInNAs/GaAs (1 1 1)B quantum wells (QWs) embedded in p-i-n diode and laser diode structures. The impact of the different growth parameters (As flux, growth temperature, growth rate, ion density) on the optical and structural properties of this material is studied by Photoluminescence and Atomic Force Microscopy. Additionally, systematic studies of rapid thermal annealing cycles have been performed to optimize the laser structures. Finally, edge-emitting laser diodes have been processed using these structures. These devices showed room-temperature laser emission above 1.2 μm under pulsed current conditions. 相似文献
144.
AIM: To study pharmacokinetics of tablet huperzine A (Hup-A) in Chinese volunteers to help establishing its drug administration schedule. METHODS: For 6 volunteers after a single oral dose of 0.99 mg, drug concentrations in plasma were assayed by reverse phase high pressure liquid chromatography (HPLC) at 0.5, 0.75, 1.0, 1.25, 1.5, 2, 4, 6, 8, and 10 h. The pharmacokinetic parameters were calculated with a 3P87 program by computer. RESULTS: The time course of plasma concentrations conformed to a one-compartment open model with a first order absorption. The pharmacokinetic parameters were as follows: T 1/2ka = 12.6 min, T 1/2ke = 288.5 min, Tmax = 79.6 min, Cmax = 8.4 micrograms L-1, AUC = 4.1 mg L-1 min. CONCLUSION: Hup-A was absorbed rapidly, distributed widely in the body, and eliminated at a moderate rate. 相似文献
145.
Antimicrobial activity of a conjugate based on two antibiotics, i.e. ristomycin A and polymyxin B was studied. The conjugate was shown to have a broad antimicrobial spectrum. In concentrations of 5 to 30 micrograms/ml it inhibited the growth of gram-positive and gram-negative bacteria and in concentrations of 5 to 40 micrograms/ml it inhibited the growth of the pathogenic clinical strains. An insignificant membranolytic action of the conjugate with respect to membranes of the susceptible bacteria and no hemolytic action on human red blood cells were detected. 相似文献
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