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991.
992.
MA Gil de Bernabé M Ferrándiz B Oliver A Russi J Molet F Vidal 《Canadian Metallurgical Quarterly》1993,40(5):273-278
OBJECTIVES: To evaluate the efficacy of general anesthesia during epileptic surgery. MATERIAL AND METHODS: A retrospective study of 64 patients who received general anesthesia during epileptic surgery. In the preoperative period, anticonvulsive medication was adjusted in accordance with plasma levels and withdrawn entirely 8 hours before surgery. After premedication with droperidol and fentanyl, a balanced anesthetic technique was applied, based on pentothal, pancuronium (or vecuronium), fentanyl, N2O and isoflurane. Continuous monitoring of ECG, arterial blood pressure, pulse oximetry, ET CO2 and neuromuscular function. Isoflurane was stopped for 10 min after the opening of the duramadre so that ECoG could be recorded and methohexital or propofol was given in some cases in order to activate the epileptogenic focus. Muscular relaxation was restored intraoperatively following the study of somatosensory evoked potentials. Immediate and later complications related to anesthesia or surgery were recorded. RESULTS: The surgical procedure performed in most cases was temporal or frontal resection, with a mean duration for anesthesia of 377 +/- 50 min and for surgery of 318 +/- 50 min. Only one patient received local anesthesia and no hemodynamic changes were observed. Perioperative complications were cerebral edema (4 cases), arrhythmia (2 cases) and bronchospasm (1 case). Postoperative complications were as follows: 3 of 9 patients undergoing callosotomy required mechanical ventilation for 24 hours, 4 patients experienced language alterations, 3 wounds were infected, 2 cases of hemiplegia were observed, 1 status epilepticus occurred after administration of propofol and there was 1 case of respiratory distress. Anticonvulsive medication was given parenterally after surgery. CONCLUSIONS: General anesthesia is a safe and effective method for epileptic surgery, with local anesthesia providing additional sedation for isolated cases. Appropriate treatment requires an understanding of the pharmacokinetics and pharmacodynamics of the drugs used, as well as knowledge of the condition and the anticonvulsive medications used. 相似文献
993.
Antagonistic effect of Enterococcus faecium J96 against human and poultry pathogenic Salmonella spp.
Production of antagonistic compounds was studied in a strain of Enterococcus faecium isolated from the intestinal tract of a free-ranging chicken. Production of lactic acid and a bacteriocin was observed in cultures of this bacterium, alone and in mixed culture fermentations with pathogenic Salmonella serotypes (i.e., Gallinarum, Pullorum, Enteritidis, and Typhimurium). Growth inhibition of these avian and human pathogens was observed after 4 h of incubation at 37 degrees C in CAm broth, a medium developed according to the nutrients present in chicken food. The antibacterial action was due to the combined effect of lactic acid and bacteriocin. Accumulation of these metabolites caused both a bacteriostatic and a bactericidal action against the gram-negative bacteria assayed. 相似文献
994.
J Vivas M Contreras C Mathew S Peraza I Maury de Tami W Oliver E Cano D Castro O Andrade V Sanchez 《Canadian Metallurgical Quarterly》1993,47(3):150-156
The Helicobacter Pylori has been indicated as a pathologic agent in the pathogenesis of antral gastritis, gastric and duodenal ulcers and probably in gastric cancer. Due to the high incidence of this infection in our place, we decided to look for a diagnostic method quick to perform, sensitive, reliable and no invasive. The breath test of 14C urea, based in the production of urea by the H. Pylori, represents this alternative. We have found, using does of 1 microCi, a high correlation with the diagnosis of H. Pylori by biopsies. We determined as negative less than 100 DPM, doubtful between 100 and 200 DPM and positive more than 200 DPM. The high pick of the curve keeps tight relation with the degree of infection. We checked this when we suppressed the H. Pylori with bismuth subsalicylate. The breath 14C Urea test showed high sensitivity (100%) and specificity (85.71%). We conclude that this breath test is an alternative way of diagnosing and follow up for H. Pylori infections. It is highly sensitive, reproducible and no invasive. 相似文献
995.
J. Oliver A. E. Huespe M. D. G. Pulido E. Samaniego 《International journal for numerical methods in engineering》2003,56(7):1051-1082
Taking the strong discontinuity approach as a framework for modelling displacement discontinuities and strain localization phenomena, this work extends previous results in infinitesimal strain settings to finite deformation scenarios. By means of the strong discontinuity analysis, and taking isotropic damage models as target continuum (stress–strain) constitutive equation, projected discrete (tractions–displacement jumps) constitutive models are derived, together with the strong discontinuity conditions that restrict the stress states at the discontinuous regime. A variable bandwidth model, to automatically induce those strong discontinuity conditions, and a discontinuous bifurcation procedure, to determine the initiation and propagation of the discontinuity, are briefly sketched. The large strain counterpart of a non‐symmetric finite element with embedded discontinuities, frequently considered in the strong discontinuity approach for infinitesimal strains, is then presented. Finally, some numerical experiments display the theoretical issues, and emphasize the role of the large strain kinematics in the obtained results. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
996.
Oliver G. McGee 《International journal for numerical methods in engineering》1992,35(2):325-349
Exact natural frequencies are determined for the torsional vibration of pretwisted thin-walled open-profile bars having torsionally clamped and pinned end restraints. The equation of motion and boundary conditions are derived from a multifilament model of a pretwisted thin-walled bar undergoing warp deformation and a moderately large twist about the elastic axis. Closed-form torsional frequencies and mode shapes are derived from the linear terms of the resulting non-linear equations. As the length-to-leg ratio (L/b) and leg-to-thickness ratio (b/t) of typical open-profile bars are varied, the individual and collective effects of warping and pretwist on the non-dimensional torsional frequencies are demarcated. In addition, the closed-form solutions offered here reveal considerable destiffening of the torsional frequencies due to warping-pretwist coupling present in thin-walled bars having pretwisted, unsymmetrical, open-profiles and torsionally clamped and pinned end restraints. This coupling effect, which have been ignored in thin-walled bar vibration theories hitherto, is brought out by the Wagner effect and warping shear stresses acting on the profiles. 相似文献
997.
S. de Freitas M. Oliver † A. Mee‡ & T. Mayes§ 《Journal of Computer Assisted Learning》2008,24(1):26-38
Abstract The promotion of e-learning in policies internationally has led to questions about how best to employ technology in support of learning. A range of models has since been developed that attempts to relate pedagogy to technology. However, research into the effectiveness of such models in changing teaching practice is sparse, and work that compares these models to practitioners' own representations of their practice is absent. The study described here involved asking practitioners to model their own practice, and to compare these with a model developed by a government organization. Practitioners were adept at using existing models and repurposing them to suit their own context. Our research provided evidence of broad acceptance of the existing model with practitioners, but indicated that practitioners would take this tool and remodel it for their own contexts of learning to make it meaningful, relevant and useful to them. 相似文献
998.
999.
By taking advantage of both the semiconductor properties and the advanced micromachining possibilities of silicon, integration of back-side photodiodes with a microfluidic channel network on a single substrate is accomplished. The resulting microsystem has all fluidic and electrical connections on one side of the chip. Hermetic sealing by anodic bonding is greatly facilitated by the simple topography on the front-side of the chip. To test the chemical functionality and performance of the device a chemiluminescence-based detection scheme is implemented. The introduction and control of the necessary chemical solutions is achieved using a flow injection analysis approach. Hydrogen peroxide is used as a model compound; injected plugs with concentrations in the range of 100 μM to 1 mM are successfully detected. 相似文献
1000.
Roberto Lancellotti Dr. Oliver Schein Dr. Stefan Spang Dr. Volker Stadler 《WIRTSCHAFTSINFORMATIK》2003,45(2):131-141
Outsourcing of ICT (Information and communications technology) and Operations services has reappeared on the agenda of top management in European banking. As a contribution to this important topic, McKinsey & Company has carried out a comprehensive survey, based primarily on 70 interviews with executives of banks and providers. Key topics analyzed are: the relevance of outsourcing to address current challenges in banking; the value created by outsourcing and the barriers to its successful implementation; the degree of viability of outsourcing across specific services and functions; and likely developments in the outsourcing market. In addition, industry best practices have been collected and synthesized. 相似文献