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排序方式: 共有3225条查询结果,搜索用时 15 毫秒
931.
Two new cases of Veratrum poisoning are described. Clinical symptoms occurred quickly, within 30 min. Vomiting, a fall in blood pressure and bradycardia were observed. The outcome was favourable in both cases, producing a cure without sequellae. Examination of the literature showed that such cases are nearly always accidental, resulting from the difficulty in distinguishing Veratrum album and Gentiana. 相似文献
932.
F Leroy EP McFadden JM Lablanche C Bauters P Quandalle ME Bertrand 《Canadian Metallurgical Quarterly》1993,14(11):1471-1475
Clinical, exercise, and angiographic variables, and long-term follow-up were compared in patients, who, during maximal Bruce exercise testing after a first acute myocardial infarction (AMI), had positive responses to exercise testing (n = 116, 38% of 303) with (n = 23, group I) or without (n = 93, group II) angina. Group I patients more often (52 vs 19%, P < 0.001) had a history of pre-infarction angina. Group II had a greater proportion (75 vs 52%, P < 0.05) of inferior wall AMI, whereas group I had a greater proportion (30 vs 19%, P < 0.01) of non-Q wave AMI. Total exercise duration was significantly (P < 0.01) longer in group II (7.6 +/- 3.2 vs 5.5 +/- 3.1 min). Maximal exercise heart rate (144 +/- 22 vs 133 +/- 21, beats.min-1 P < 0.05) was also higher in group II. A greater proportion of group II patients (37 vs 9%, P < 0.05) had single-vessel disease, whereas multivessel disease was more common (91 vs 63%, P < 0.03) in group I. Left ventricular function was similar in both groups. During follow-up (48 +/- 22 months) the incidence of cardiac death (group I, 3.3%, group II, 4.8%), of recurrent infarction (group I, 4.8%, group II 3.3%), and of revascularization procedures (group I, 28.5%, group II, 19.8%) were similar in both groups. Although asymptomatic exercise-induced ischaemia was associated with better exercise performance and less extensive coronary disease than symptomatic ischaemia, it had the same long-term prognostic implications. 相似文献
933.
Submarine hull integrity under blast loading 总被引:1,自引:0,他引:1
Bertrand Langrand Nicolas Leconte Aude Menegazzi Thierry Millot 《International Journal of Impact Engineering》2009
The paper deals with numerical methodologies to model and study the structural resistance of submarine hull against explosions, where fluid and solid phenomena interact. Explosion Crack Starter Tests (ECST), which are a standard procedure to study submarine materials and weldments with respect to blast loading, are modelled using an explicit FE code that solves Fluid/Structure (F/S) interactions within the same computation. The proposed numerical methods aim at computing the structural response of a target subjected to sequential explosions. Numerical results are compared to the corresponding explosion tests (ECST) performed by DGA (French Ministry of Defence). 相似文献
934.
T. Onat Ekinci J.R.R. Mayer Guy M. Cloutier 《International Journal of Machine Tools and Manufacture》2009,49(6):478-487
Aerostatic guideways are often used in machines requiring very high motion accuracy such as coordinate measuring machines. Currently, positioning error analysis for such machines focuses on the relationship between volumetric errors on one hand and axes’ motion errors and axes’ relative location errors on the other. The internal mechanisms causing motion errors are rarely considered. In order to gain a deeper understanding of aerostatic guideways, this paper investigates the relationship between the motion errors of the axis’ carriage and the guideways’ geometric errors both mathematically and experimentally. The analytical model uses bearings location and stiffness, guideway geometry and static equilibrium to produce a model in matrix form. Validation experiments are conducted on a machine axis moving on aerostatic guideways with and without preload. 相似文献
935.
936.
937.
V Augier M Asso B Guigliarelli C More P Bertrand CL Santini F Blasco M Chippaux G Giordano 《Canadian Metallurgical Quarterly》1993,32(19):5099-5108
The beta-subunit of the nitrate reductase of Escherichia coli contains four groups of Cys residues (I-IV) which are thought to bind the single [3Fe-4S] center and the three [4Fe-4S] centers. The first or second Cys residue of group I was substituted by site-directed mutagenesis with Ala or Ser. Physiological, biochemical, and EPR studies were performed on the mutated enzymes. With small variations, the properties of these mutant enzymes do not differ from one another. They were found to be as abundant and as stably bound to the membrane as the native enzyme, provided the gamma-subunit was present. Although physiological activity was reduced, it was sufficient to allow growth on nitrate. The study of variations in EPR intensity as a function of the redox potential indicated that these enzymes only contained three iron-sulfur centers instead of the usual four in the native enzyme. Spectral EPR analysis showed that the [4Fe-4S] center of high redox potential (center 1, +80 mV) was missing. The loss of this center did not affect the stable integration of the other three centers. The data presented here are in total contrast to those we have reported for each of the other three centers (centers 2-4), the loss of which was detrimental to the integration of all centers and to the integration of the molybdenum cofactor (Augier et al., in press). Taken together, our results demonstrated that the first and second Cys residues of group I are the ligands of the [4Fe-4S] center (center 1, +80 mV) and that this center participates in electron transfer, but is dispensable. On the basis of these results, it is proposed that the [3Fe-4S] center (center 2, +60 mV) also plays a biological role and that in the native enzyme both high-potential centers, centers 1 and 2, contribute independently and in parallel to the electron transfer to the molybdenum cofactor. 相似文献
938.
This is a study of housing supply in three urban areas in Ghana: Accra the capital city, Kumasi, the most important provincial city, and Berekum, a small town. The sample of over 1600 households is divided into renters, recent owners, and longer established owners. The last group is divided into those who have and those who have not extended their home in the previous 6 years. The data provides an insight into who is supplying houses (and extensions), what sort of housing they are building, their reasons for building and the problems encountered in achieving ownership. The study shows that house ownership is available to much lower income households than expected, especially when traditional compounds are built; that owners are relatively old, have large households and occupy considerably more rooms than renters, and build houses larger than they need and let the remainder to tenants or relatives. There is a great need for housing finance because land is currently inappropriate for collateral against a building loan. Research is needed to develop a means by which land could be used as collateral for a loan without unravelling the customary non-marketability of land. 相似文献
939.
The authors propose a technique for on-chip analogue response compaction to implement self-test capabilities in analogue circuits. The integration function is identified as a powerful analogue compression scheme and op-amp-based implementations are proposed for both single and multiple-input analysers. Validations show that an improved fault coverage can be achieved 相似文献
940.
Bouffard Thérèse; Vezeau Carole; Romano Guy; Chouinard Roch; Bordeleau Luce; Filion Catherine 《Canadian Metallurgical Quarterly》1998,30(3):203
Recent research on school motivation underlines the crucial role played by the types of goals chosen by students in determining their functioning and achievement. The aim of this study was to create and validate a questionnaire of goals in the academic setting adapted for a population of French students from high school to university. The 1st study comprised 542 students, and the factor analysis confirmed that the instrument allows for the discrimination of mastery, performance, and avoidance goals. The temporal stability of the instrument was shown in the 2nd study comprising 292 students, whereas the 3rd study, involving 355 students, confirmed its concurrent validity. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献