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排序方式: 共有1197条查询结果,搜索用时 15 毫秒
151.
A Kobayashi S Hashimoto K Kooguchi Y Kitamura H Onodera Y Urata T Ashihara 《Canadian Metallurgical Quarterly》1998,113(6):1632-1639
Cytochrome bo is a four-subunit quinol oxidase in the aerobic respiratory chain of Escherichia coli and functions as a redox-coupled proton pump. Subunit I binds all the redox metal centers, low-spin heme b, high-spin heme o, and CuB, whose axial ligands have been identified to be six invariant histidines. This work explored the possible roles of the aromatic amino acid residues conserved in the putative transmembrane helices (or at the boundary of the membrane) of subunit I. Sixteen aromatic amino acid residues were individually substituted by Leu, except for Tyr61 and Trp282 by Phe and Phe415 by Trp. Leu substitutions of Trp280 and Tyr288 in helix VI, Trp331 in loop VII-VIII, and Phe348 in helix VIII reduced the catalytic activity, whereas all other mutations did not affect the in vivo activity. Spectroscopic analyses of the purified mutant enzymes revealed that the defects were attributable to perturbations of the binuclear center. On the basis of these findings and recent crystallographic studies on cytochrome c oxidases, we discuss the possible roles of the conserved aromatic amino acid residues in subunit I of the heme-copper terminal oxidases. 相似文献
152.
T Nakatani Y Sasako J Kobayashi K Komamura Y Kosakai K Nakano F Yamamoto K Kumon K Miyatake S Kitamura H Takano 《Canadian Metallurgical Quarterly》1998,44(5):M516-M520
Effects of long-term left ventricular (LV) support on end-stage cardiomyopathy patients is unclear. We applied our LV assist system (LVAS) to six heart transplant candidates, aged 17 to 49, with dilated cardiomyopathy, including one dilated phase hypertrophied cardiomyopathy. LVAS was installed between the left atrium and the ascending aorta, and the pump was positioned parecorporeally. In all patients, their general condition improved, and their pump flows were kept at 4 to 5 L/min. Exercise was started after stabilization of their general condition under constant pump flow. Natural heart size and function were examined by echocardiography. In the beginning of assist, all patients showed impaired cardiac function and LV dilation. During LV assist, systolic function measured by ejection time improved in all patients. Left ventricular end-diastolic dimension (LVDd), showed a remarkable decrease in two patients, who were weaned from LVAS after 3 months of support. They are doing well more than 1 year and 3 years after removal; peak VO2 levels (ml/min/kg) were 30 at 1.2 years and 27 at 2.7 years after removal. In the other four patients, however, LVDd had no remarkable changes, and three could not be weaned from LVAS. The last was discontinued from LVAS after 5 months of support because of infection and died 2 months after removal. From this experience, long-term LVAS may provide the chance for recovery of the natural heart in patients with end-stage cardiomyopathy. The patients whose hearts showed remodeling were able to be weaned from LVAS, and their heart function maintained in good condition for several years. 相似文献
153.
Drivers' Mental Representation of Travel Time and Departure Time Choice in Uncertain Traffic Network Conditions 总被引:2,自引:0,他引:2
The decisions drivers make, such as choice of route or departure time, constitute typical decision making under uncertainty. Drivers' decision making has been studied within the framework of expected utility theory. However, empirical decisional phenomena violating the premise of expected utility theory have been observed repeatedly. These findings have indicated that decision making is critically affected by the decision frame. It has also been pointed out that the uncertainty of outcome is perceived as an interval of possible resultant values. Based on these findings, we propose hypotheses that: (1) a driver perceives an uncertain travel time as an interval, and (2) a driver decides on a departure time based on a decision frame edited by this interval. To test these hypotheses, we collected data on drivers' departure time choice behavior, n = 335. Decisional phenomena found in this study confirm our hypotheses. 相似文献
154.
Kitamura T. Yoshida K. Geshiro M. Ishizaki T. 《Microwave and Wireless Components Letters, IEEE》2003,13(8):357-359
We propose a new type of comb-line filter that is suitable for miniaturization utilizing stratifying technology. It consists of a couple of composite resonators. Each resonator is composed of two sections of a microstrip and a coplanar waveguide fabricated on the microstrip ground plane which are connected through a piece of wire at an open end to set up a new folded comb-line filter. The filtering characteristics are investigated through experiments as well as numerical simulations by means of the FD-TD method. It is shown that the filtering characteristics can be much improved by removing part of the barrier in the coplanar-line portion of the resonator to alter the coupling. 相似文献
155.
H Taniguchi T Takahashi K Sawai T Yamaguchi A Hagiwara K Kitamura M Hoshima M Masuyama T Mugitani A Takada A Yamaguchi 《Canadian Metallurgical Quarterly》1997,44(15):897-900
BACKGROUND/AIM: The outcome after hepatectomy and non-surgical treatment of liver metastases from gastric and colorectal malignancies are reported. METHODOLOGY: Between April 1988 and March 1994, 176 patients with metastatic liver cancer were treated at the First Department of Surgery, Kyoto Prefectural University of Medicine Hospital. RESULTS: All patients received multi-disciplinary treatment, and 51 underwent hepatectomy. The survival after hepatectomy for metastatic liver cancer from a colorectal primary was better than that for gastric cancer. The survival after hepatic arterial infusion (HAI) therapy for metastases from gastric cancer was better than that for colorectal cancer. CONCLUSION: Surgical resection may be the best treatment for liver metastases from colorectal cancer. HAI may be a better option for liver metastases from gastric cancer. 相似文献
156.
The relation between bending strength and X-ray diffraction intensity for pulp cement board composed of separated pulp from municipal solid waste was studied. Higher bending strength was observed for the boards with higher diffraction intensity of Ca(OH)2. Lower bending strength at the same diffraction intensity was observed for the boards from coarsely separated pulps than those from other pulps used. This difference in bending strength was discussed in relation to the differences in the strength of pulp and the amount of fine fraction in pulp. 相似文献
157.
The type II protein kinase C (PKC-II) densely present in mammalian brain plays functional roles in CNS. We examined the characteristics of [3H]staurosporine binding to PKC-II purified from rat brain, compared to [3H]phorbol 12, 13-dibutyrate (PDBu) binding. In brief, [3H]staurosporine binding increased by phosphatidylserine (PtdSer) in a concentration-dependent manner and the binding was enhanced by Ca2+ and phorbol 12-myristate 13-acetate (PMA). In the presence of Ca2+, PMA and PtdSer, Bmax of these bindings markedly increased, but KD did not change. These characteristics of binding were similar to [3H]PDBu binding to PKC-II. Although [3H]PDBu binding was not affected by protein kinase inhibitors such as staurosporine, H-7, K-252a and K-252b, [3H]staurosporine binding was inhibited by these inhibitors. [3H]staurosporine binding was inhibited by several ATP analogues, but was not by guanine nucleotides. PtdSer-induced increase in [3H]PDBu binding was inhibited by Zn2+, but Zn2+ induced increase in [3H]staurosporine binding as well as PtdSer and/or Ca2+. Staurosporine would thus appear to bind to a domain different from phorbol ester-binding one in PKC, interactions between both domains may regulate kinase activity, and 1 mol staurosporine and 4 mol phorbol ester may bind to 1 mol PKC-II. 相似文献
158.
159.
160.
Mito I. Kitamura M. Kaede K. Odagiri Y. Seki M. Sugimoto M. Kobayashi K. 《Electronics letters》1982,18(1):2-3
Using a new LPE growth technique, an InGaAsP/InP planar buried heterostructure laser diode (PBH-LD) has been realised in 1.3 and 1.5 ?m wavelength regions. As a result of the effective carrier confinement, CW threshold currents as low as 8.5 mA and 13 mA have been obtained in 1.3 and 1.5 ?m PHB-LDs, respectively, at room temperature. 相似文献