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Dissection of the thoracic aorta is a life-threatening event requiring imaging studies to define the level of the tear and the intinmal flap. The “gold standard” has been angiography. This method may fail to demonstrate the dissection, however, due to overlap of the true and false lumens or a very thin flap that is imaged en face rather than tangentially. Computed tomography has a diagnostic accuracy of 95%, but can fail to image the dissection due to technical factors or a thrombosed false hunen. Magnetic resonance imaging requires a hemodynamically stable and cooperative patient. A diagnostic algorithm is proposed for diagnosis of aortic dissection based on renal function and the surgeon's imaging modality preference.  相似文献   
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The performances of three widely different cathode materials (Pt, strontium-doped lanthanum manganite (LSM), and NiO) have been compared for use with proton conducting Li2SO4–Al2O3 composite electrolyte, using H2S–air and H2–air fuel cells operating at 600 °C. Surface analysis and electrochemical techniques were used to characterize fresh and used electrode materials. Pt or LSM cathodes each became covered with Li2SO4 and Al2O3 and, as a consequence, the fuel cells showed poor performance. In contrast, the NiO cathode catalyst did not become covered with Li2SO4 and good fuel cell performance was achieved. Exceptionally good current densities of over 100 mA/cm2 and power densities of over 30 mW/cm2 were obtained for H2S–air fuel cells having Mo–Ni–S anode catalysts. Slight agglomeration of NiO particles during fuel cell operation had only a minor effect on performance.  相似文献   
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A range of 18 derivatives of flavone-8-acetic acid (FAA) with substituents on the 2-phenyl group have been prepared and their anti-tumour activity evaluated in vitro against a panel of human and murine tumour cell lines and in vivo against MAC 15A. There was no clear-cut relationship between in vitro and in vivo activity but the activity in each situation was found to be very sensitive to the precise substitution pattern with closely related isomers giving widely different activities. Some of the compounds, notably 10b,cj , and r , were active in vivo and these require further studies in order to evaluate their potential for development.  相似文献   
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Nociceptin (Orphanin FQ) is a newly discovered endogenous heptadecapeptide substrate for the opioid-receptor-like 1 receptor, a G protein coupled receptor that bears striking amino acid sequence homology to opiate receptors. In rats, intrathecal (i.t.) administration of nociceptin is without effect on basal thresholds for responsiveness to electric foot shock. However, during either late gestation or its hormonal simulation, when nociceptive thresholds are elevated by approximately 70%, i.t. nociceptin substantially attenuates jump thresholds in a dose-dependent fashion. This hypoalgesic effect of nociceptin is not limited to attenuating the gestational or sex steroid-induced increment in pain thresholds. Following the highest i.t. dose of nociceptin employed (20 nmol), the gestational or sex steroid-induced increment in jump thresholds is not only abolished but a significant hyperalgesia is observed. These results underscore the importance of the hormonal milieu to nociceptin hypoalgesic sensitivity. The potential contribution of spinal nociceptive pathways that utilize nociceptin to the etiology of extraordinary painful pregnancy and labor should not be ignored.  相似文献   
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Australian nursing has undergone rapid academization in the past 10 years and this radical change has tended to meld the somewhat different academic traditions of North America and Britain. The introduction of doctoral education in nursing in 1987 has led to a massive increase in scholarly activity and to the preparation of talented leaders. We concur with the view expressed by Henry (1997), "I am convinced that the problems we face in the nursing services would be much more creatively solved if the majority of our doctoral programs prepared young, energetic nurses, early in their career, for clinical practice, not for research and teaching" (p. 162).  相似文献   
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High-Risk Drinking across the Transition from High School to College   总被引:4,自引:0,他引:4  
Alcohol use and related problems were studied from the senior year in high school to the first autumn in college for 366 heavy drinking students. Four risk factors-subject sex, family history of drinking problems, prior conduct problems, and type of college residence-were evaluated as predictors of: (1) differential changes in drinking rates, (2) differential changes in alcohol-related problems, and (3) alcohol dependence symptoms during the first college term. Results suggest that both dispositional and environmental factors are associated with changes in drinking rates and the existence of dependence symptoms. Increases in the frequency of drinking were specifically and strongly associated with residence in a fraternity (men) or sorority (women). Three risk factors were associated with increased quantity of drinking: male gender, residence in a fraternity or sorority, and a history of conduct problems. Prior conduct problems were also consistently associated with dependence symptoms during the first term in college. A family history of alcohol problems was not consistently related to changes in use rates or problems, although some analyses suggest interactive effects. Early interventions on college campuses should target individuals using additive risk profiles.  相似文献   
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