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排序方式: 共有805条查询结果,搜索用时 15 毫秒
101.
H Uemura T Yagihara K Yamashita T Ishizaka K Yoshizumi Y Kawahira 《Canadian Metallurgical Quarterly》1998,13(5):504-7; discussion 508
OBJECTIVE: To minimize deleterious postoperative influences of cardiopulmonary bypass on the pulmonary circulation immediately after the Fontan type procedure, total cavopulmonary connection was achieved without use of cardiopulmonary bypass. METHODS: Since April 1996, 15 patients including five patients with visceral heterotaxy, in whom no intracardiac procedure was needed, have undergone this operative maneuver. Age at operation ranged from 1.2 to 44.6 years. Construction of a systemic to pulmonary shunt had been previously employed in seven patients, banding of the pulmonary trunk in two patients, and the Norwood procedure in one patient. The superior caval vein was initially anastomosed to the pulmonary arteries in bidirectional fashion under temporary bypass from the superior caval vein to the atrium. The channel for draining the inferior caval vein was subsequently constructed with the aid of temporary bypass from the inferior caval vein to the atrium, using a Goretex tube in ten patients, using a pedicled autologous pericardial roll in four patients, and directly anastomosing the pulmonary trunk to the orifice of the inferior caval vein in one patient. In patients with visceral heterotaxy and an independent hepatic venous drainage, redirection of the blood flow via the caval vein as well as the hepatic vein could be successfully achieved by placing dual temporary bypasses into these veins. RESULTS: Postoperative courses were excellent in all patients. Superior caval venous pressure was 11 +/- 2 mmHg at 12 h after the operation. No blood transfusion was needed in nine patients(60%). CONCLUSION: This alternative operative procedure is undoubtedly attractive when establishing the Fontan circulation in patients undergoing no intracardiac maneuvers. 相似文献
102.
BACKGROUND: Significant changes in cardiac preload and afterload are generated by a number of factors present during the operation of high performance aircraft. These include high levels of +Gz, positive pressure breathing and anti-G straining maneuvers. Centrifuge subjects are exposed to these same factors in doses that are comparable to their operational counterparts. The question of whether such exposures produce long-term adverse effects on the heart has not been definitively answered. METHODS: In an effort to further address this issue, a longitudinal study was conducted on 18 newly recruited centrifuge panel members (7 males and 11 females) who did not have a previous history of significant high +Gz exposure. In order to document the cumulative long-term effects of high +Gz exposure and G protection measures, baseline echocardiographic studies were conducted prior to any +Gz exposure on the Dynamic Environment Simulator (DES) centrifuge. The echocardiograms were repeated after each panel member completed eight sessions of indoctrination. These follow-up echos were performed after all 18 subjects had been exposed to over 45 min (cumulative) of sustained acceleration > or = 2 G. Each subject served as his/her own control. All studies were evaluated independently by a cardiologist who was blinded to the order in which the studies were performed. Although complete echocardiographic studies were performed, only the parameters identified as significant in prior studies were evaluated. RESULTS: No significant differences were found between the initial and follow-up echo parameters. No significant differences were found between male and female responses. CONCLUSIONS: We found no significant differences in cardiac function after 45 min (cumulative) of exposure to G > or = 2 in men or women. These subjects will be monitored during a longitudinal study throughout their centrifuge subject career. 相似文献
103.
Shigeki Sakaguchi Yozo Sawaki Yoshishige Abe Tadashi Kawasaki 《Journal of Materials Science》1982,17(10):2878-2886
Stable crack-propagation behaviour in silica glass as a raw material for optical fibres is studied under static tensile stress in various environments such as distilled water, NaCl aqueous solution, air and dry nitrogen gas, and the influence of these environments is discussed. The crack-growth rate in distilled water is obtained qualitatively as a function of the stress intensity factor and temperature, and the activation energy of the cracking process is determined as 97.6 kcal mol–1. The growth rate seems to be unaffected by Na+ and Cl– ions in an NaCl acqueous solution, but is influenced significantly by the humidity in the atmosphere. In a dry atmosphere, the growth rate in Region II cannot be expressed as a single function of the stress intensity factor. A plot of the log of time to failure against the initial stress intensity factor reveals a linear relationship in the environments tested. The critical fracture stress of an optical fibre is evaluated taking account of the crack size on the basis of fracture mechanics concept. 相似文献
104.
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106.
Toshio Tanaka Shigeki Suzuki Yoshitsugu Nekomoto Mamoru Tanaka 《Nuclear Engineering and Design》1994,147(3)
This paper deals with a diagnostic and monitoring system for assessing the integrity of pipe branches, during the operation of the nuclear power plant. This system have been developed under the concept of “easy to use without any sophisticated analysis” and “portable”. The accuracy of the diagnosis is based on the model optimization subsystem, which automatically modifies the numerical vibration model so as to fit its natural frequency to the actual natural frequency. The information obtained by this system may be reflected to a maintenance program of the plant to assure more reliable operation of the plant. 相似文献
107.
Video Scene Annotation Based on Web Social Activities 总被引:1,自引:0,他引:1
This article describes a mechanism to acquire the semantics of video content from the activities of Web communities that use a bulletin-board system and weblog tools to discuss video scenes. 相似文献
108.
We varied the promoter strength of xylose reductase (XR) gene and the copy number of xylulokinase (XK) gene to determine how XR and XK activities affect the xylose-fermenting abilities of recombinant Saccharomyces cerevisiae expressing xylitol dehydrogenase (XDH). The most enhanced ethanol yield and lowered xylitol yield occurred in strain I-PGK/AUR, which has high activity of both XR and XDH and moderate XK activity. 相似文献
109.
Acremonium cellulolyticus is a fungus that produces cellulase and has been exploited by enzyme industry. To promote cellulase production by A. cellulolyticus strain C-1, we evaluated the effects of the saccharides: Solka Floc (cellulose), soluble soybean polysaccharide (SSPS), pullulan, lactose, trehalose, sophorose, cellobiose, galactose, sorbose, lactobionic acid, and mixtures as carbon sources for cellulase production. Solka Floc with SSPS enhanced cellulase production. Lactose as the sole carbon source induced cellulase synthesis in this fungus, and the synergistic effects between lactose and Solka Floc was observed. Various enzyme activities and the protein composition of crude enzyme produced by cultures with or without addition of lactose were analyzed. The results showed that lactose addition greatly improves the production of various proteins with cellulase activity by A. cellulolyticus. To our knowledge, this is the first report on production of cellulases by lactose in the A. cellulolyticus. 相似文献
110.