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101.
The distribution of brain-derived neurotrophic factor (BDNF) in the song system of male zebra finches changes with posthatching age. At day 20, the hyperstriatum ventrale, pars caudale is the only song nucleus in which neurons showed BDNF immunoreactivity. At day 45, the staining in hyperstriatum ventrale, pars caudale was denser than at day 20 and the robust nucleus of the archistriatum, another song nucleus, showed BDNF labeling. By day 65, two additional song nuclei, area X and the lateral magnocellular nucleus of the anterior neostriatum, have become immunoreactive. In the adult, however, the amount of BDNF labeling in all of these brain nuclei is sharply reduced. These sequential events, the anatomical connections between these song nuclei, and the labeling of relevant axons and terminals suggest anterograde transport of BDNF. Furthermore, the timing of BDNF expression coincident with the development of singing behavior suggests that this neurotrophin may be directly involved with the differentiation of the song system. 相似文献
102.
H Kobayashi Y Kotoura M Hosono R Fujimoto T Tsuboyama H Itoh J Konishi 《Canadian Metallurgical Quarterly》1995,19(5):419-422
We report pre- and post-operative three-dimensional (3D)-spiral CT images in a patient with multiple exostoses. Images of 3D-CT, which were performed using the integrated 3D software of the CT system, showed the exact shapes and locations of the individual tumors around the knee joint in comparison with the surgical findings and resected specimen. 3D-spiral CT images of multiple exostoses would be useful for the planning of surgical procedure. 相似文献
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106.
H. Sasaki DG K. Yajima N. Yoshida T. Ishida R. Hattori T. Sonoda O. Ishihara S. Takamiya R. Konishi K. Ando 《Journal of Electronic Materials》1996,25(5):559-563
We have investigated the degradation mechanism of Al0.48In0.52As/In0.53Ga0.47As/ InP high electron mobility transistors (HEMTs) using WSi ohmic electrodes. Cross-sectional transmission electron microscopy
(TEM) observation and en-ergy dispersive x-ray (EDX) analysis reveal impurities diffusion of gate electrode (titanium: Ti)
and fluorine (F) in the AlInAs layer after a high temperature (Ta = 170°C operating life test for 500 h. The decrease of drain current (Ids) during life test shows linear dependence on square root of aging time. It suggests that the degradation is controlled by
a diffusion mechanism. Hence, the estimated degradation mechanism of this device is related with decrease of carrier concentration
in the epitaxial layer by these diffused impurities. On the other hand, TEM and EDX show no degradation of WSi/InGaAs interface
after aging. Therefore, the WSi electrode for this type of HEMT demonstrates excellent high stability under the accelerated
operating life test. 相似文献
107.
Metallic Cu electrode can electrochemically reduce CO2 to CH4, C2H4 and alcohols with high yields as revealed by the present authors. Many workers reported that formation of CH4 and C2H4 rapidly diminishes during electrolysis of CO2 reduction. This paper shows that such deactivation of Cu electrode is reproduced with electrolyte solutions prepared from reagents used by these workers. Deactivated Cu electrodes recovered the electrocatalytic activity for CO2 reduction by anodic polarization at −0.05 V versus she in agreement with the previous reports. Features of the deactivation depend greatly on the individual chemical reagents. Purification of the electrolyte solution by preelectrolysis with a Pt black electrode effectively prevents the deactivation of Cu electrode. Anode stripping voltammetry of Cu electrodes, which were deactivated during electrolysis of CO2 reduction, showed anodic oxidation peaks at ca. −0.1 or −0.56 V versus she. The severer the deactivation of the Cu electrode was, the higher electric charge of the anodic peak was observed. It is presumed that some impurity heavy metal, originally contained in the electrolyte, is deposited on the Cu electrode during the CO2 reduction, poisoning the electrocatalytic activity. On the basis of the potential of the anodic peaks, Fe2+ and Zn2+ are assumed to be the major contaminants, which cause the deactivation of the Cu electrode. Deliberate addition of Fe2+ or Zn2+ to the electrolyte solutions purified by preelectrolysis exactly reproduced the deactivation of a Cu electrode in CO2 reduction. The amount of the deposited Fe or Zn on the electrode was below the monolayer coverage. Electrothermal atomic absorption spectrometry (etaas) showed that Fe originally contained in the electrolyte solution is effectively removed by the preelectrolysis of the solution. Mechanistic difference is discussed between Fe and Zn in the deterioration of the electrocatalytic property of Cu electrode in the CO2 reduction. The concentration of the impurity substances originally contained in the chemical reagents as Fe or Zn is estimated to be far below the standard of the impurity levels guaranteed by the manufacturers. Presence of trimethylamine in the electrolyte solution also severely poisons a Cu electrode in the CO2 reduction. It was concluded that the deactivation of Cu electrode in CO2 reduction is not caused by adsorption of the products or the intermediates produced in CO2 reduction. 相似文献
108.
The power–voltage and current–voltage characteristics of a PV array change with the variation of insolation and temperature. In particular, the output power of a PV‐panel block consisting of series‐PV modules inevitably goes down due to partial shading caused by peripheral obstacles. This results in a significant reduction of the total output power from the PV power generation system where a couple of PV blocks are parallel to the DC terminal of interactive inverter because of mismatch of the optimum operating voltages between the PV blocks. In this paper, we propose a power conversion system to compensate the output power of a partially shaded PV array. The proposed system can control the output power of the PV array on a PV block basis, which contributes to a more efficient and simpler implementation of the PV power compensation system than that by individual controls of PV modules using DC–DC converters. In addition, inverter DC voltage is appropriately controlled so that the maximum output power from the overall PV array can be obtained. Then, the feasibility of the system is investigated and verified from the simulation and experimental results. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(3): 74–82, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10203 相似文献
109.
110.
M Yamasaki N Konishi K Yamaguchi S Itoh Y Yokoo 《Canadian Metallurgical Quarterly》1998,62(8):1528-1534
Various derivatives of recombinant human granulocyte colony-stimulating factor (rhG-CSF) have been overproduced in Escherichia coli with the strong, inducible trp promoter. A derivative designated as KW-2228 in which the amino acids were replaced at five positions showed more potent granulopoietic activity and stability than those of wild-type both in vitro and in vivo. The purification involved a sequential renaturation process and three-step chromatography. Refolding succeeded in very high yield using a urea system. The purity of KW-2228 was greater than 99% as measured by SDS-PAGE and HPLC analysis. According to circular dichroism and nuclear magnetic resonance spectroscopy, rhG-CSF and KW-2228 have very similar conformations. This suggests that the substitution of five amino acids does not appreciably change the conformation of hG-CSF. KW-2228 ([Ala1, Thr3, Tyr4, Arg5, and Ser17]-hG-CSF) and derivative A ([Ala1, Thr3, Tyr4, Arg5]-hG-CSF) are easily crystallized and they show similar in vitro activity. On the other hand, neither rhG-CSF nor derivative B ([Ser17]-hG-CSF) are crystallized under the same conditions. Thus, the four amino acid substitution (Ala1, Thr3, Tyr4, Arg5) of the N-terminal sequence may facilitate crystallization. The change of Cys17 to Ser may not influence the stability and activity of hG-CSF. 相似文献