838 resultados para competitive replacement
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Dissertação de mestrado integrado em Engenharia e Gestão Industrial
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Dissertação de mestrado integrado em Engenharia de Materiais
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OBJECTIVE: The aim of this work was the follow-up and evaluation of valve replacement in children under 12 years of age. METHODS: Forty-four children less than 12 years old were underwent valve replacement at INCOR-HCFMUSP between January 1986 and December 1992. Forty (91%) were rheumatic, 39 (88.7%) were in functional classes II or IV, 19 (43.2%) were operated upon on an emergency basis, and 6 (13.6%) had atrial fibrillation. Biological prostheses (BP) were employed in 26 patients (59.1%), and mechanical prostheses (MP) in 18 (40.9%). Mitral valves were replaced in 30 (68.7%), aortic valves in 8 (18.2%), a tricuspid valve in 1 (2.3%), and double (aortic and mitral) valves in 5 (11.4) of the patients. RESULTS: Hospital mortality was of 4.5% (2 cases). The mean follow-up period was 5.8 years. Re-operations occurred in 63.3% of the patients with BP and in 12.5% of those with MP (p=0.002). Infectious endocarditis was present in 26.3% of the BP, but in none of the cases of MP (p=0.049). Thrombosis occurred in 2 (12.5%) and hemorrhage in one (6.5%) of the patients with a MP. Delayed mortality occurred in 5 (11.9%) of the patients over a mean period of 2.6 years; four had had BP and one had a MP (NS). Actuarial survival and re-operation-free curves after 10 years were respectively, 82.5±7.7 (SD)% and 20.6±15.9%. CONCLUSION: Patients with MP required fewer re-operation, had less infectious endocarditis and lower late mortality rates compared with patients with bioprostheses. The former, therefore, appear to be the best valve replacement for pediatric patients.
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OBJECTIVE: To report the effects of 2 regimens of hormone replacement therapy during the postmenopausal period on the profile of the major lipoprotein subfractions (HDL, LDL, and VLDL). METHODS: We carried out a cohort study in 38 postmenopausal patients who were starting their hormone replacement therapy due to gynecological indications, for a period of 12 weeks. Analysis of lipoprotein subclasses was performed through nuclear magnetic resonance spectroscopy. RESULTS: Hormone replacement therapy cause an increase in the proportion of larger subfractions of VLDL and HDL (p=0.008 and 0.03, respectively) and in the proportion of larger particles of VLDL due to a 36% increase in the levels of larger particles (p=0.004), concomitantly with a 15% reduction in the levels of smaller particles (p=0.04). In regard to HDL, the increase occurred only a 17% increase in the levels of larger particles (p=0.002). No significant change occurred in the distribution pattern of LDL subfractions. CONCLUSION: The proportion of larger subfractions of VLDL and HDL increases after hormone replacement therapy. The increase in the proportion of larger particles of VLDL occurs due to an increase in the levels of the larger subclasses concomitantly with a reduction in the smaller particles. However, an increase in the proportion of larger particles of HDL occurs only due to an increase in the levels of the larger subfractions.
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We report the case of a patient with a pseudoaneurysm of the ascending aortic clinically diagnosed 5 months after surgical replacement of the aortic valve. Diagnosis was confirmed with the aid of two-dimensional echocardiography and helicoidal angiotomography. The corrective surgery, which consisted of a reinforced suture of the communication with the ascending aorta after opening and aspiration of the cavity of the pseudoaneurysm, was successfully performed through a complete sternotomy using extracorporeal circulation, femorofemoral cannulation, and moderate hypothermia, with no aortic clamping.
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OBJECTIVE: This study evaluated the effects of a new method of mitral valve replacement on left ventricular (LV) remodeling and heart failure functional class. METHODS: Eight patients (6 men) with severe mitral regurgitation from end-stage dilated cardiomyopathy underwent surgery. Five patients were in functional class (FC) IV, 2 were in FC III and 1 was in FC III/IV. Age ranged from 33 to 63 years. Both the anterior and posterior leaflets of the mitral valve were divided into hemileaflets. The resultant 4 pedicles were displaced under traction toward the left atrium and anchored between the mitral annulus and an implanted valvular prosthesis. The beating heart facilitated ideal chordae tendineae positioning. RESULTS: All patients survived and were discharged from the hospital. After a mean follow-up period of 6.5 months (1-12 m), 5 patients were in FC I; 2 in FC I/II; and 1 in FC II. The preoperative ejection fraction ranged from 19% to 30% (mean: 25.7±3.4 %), and the postoperative ejection fraction ranged from 21% to 40% (mean: 31.1± 5.8%). Doppler echocardiography showed evidence of LV remodeling in 4 patients, including lateral wall changes and a tendency of the LV cavity to return to its elliptical shape. CONCLUSION: This technique of mitral valve replacement, involving new positioning of the chordae tendineae, allowed LV remodeling and improvement in FC during this brief follow-up period.
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Rupture of the left ventricle following mitral valve replacement is a catastrophic complication with deadly consequences. We report here the case of a 75-year-old man who underwent elective mitral valve replacement for severe mitral regurgitation. Delayed type 1 rupture of the left ventricle developed 3 hours postoperatively in the intensive care unit. A salvaging maneuver was used, which gained time, allowing reoperation and successful intraventricular repair.
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La utilización de energía eólica es un hecho cada vez más común en nuestro mundo como respuesta a mitigar el creciente aumento de demanda de energía, los aumentos constantes de precio, la escasez de combustibles fósiles y los impactos del cambio climático, los que son cada día más evidentes.Consecuentemente, el interés por la participación de esta nueva forma de generación de energía en sistema eléctrico de potencia ha aumentado considerablemente en los últimos años. La incorporación de generación de origen eólico en el sistema eléctrico de potencia requiere de un análisis detallado del sistema eléctrico en su conjunto, considerando la interacción entre parques y unidades de generación eólica, plantas de generación convencional y el sistema eléctrico de potencia. La integración de generación de origen renovable en el sistema eléctrico de potencia convencional presenta nuevos desafíos los que pueden ser atribuidos a características propias de este tipo de generación, por ejemplo la fluctuación de energía debido a la naturaleza variable del viento, la naturaleza distribuida de la generación eólica y las características constructivas y método de conexión de los distintos modelos de turbinas eólicas al sistema.La finalidad de este proyecto de investigación consiste en investigar el impacto sobre un mercado de sistema eléctrico competitivo causado por el agregado de generación de origen eolico. Como punto de partida se pretende realizar modelos de plantas de generacion eolica para luego incorporarlos a los modelos de sistemas eléctricos y realizar estudios de de despacho económico, flujo de cargas, análisis transitorio y estudios dinámicos del sistema.
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Magdeburg, Univ., Fak. für Wirtschaftswiss., Diss., 2011
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n.s. no.108(2006)
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Observations reported in the present paper have shown that Biomphalaria glabrata is being gradually displaced by B. straminea in coastal areas of two counties on the state of Pernambuco, Brazil, confirming former observations made in the same region.
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For the development of laboratory experiments on the competitive interacitons between freshwater snail populations, special snail rooms were set up in the main building of the Research Center "Aggeu Magalhães". In the current paper, the first of a series on this subject, the general methodology of the laboratory work is described in detail. Using indoor cement channels in which a uniform seminatural environment was created, interactions of freshwater snail populations can be studied with minimal interference of the usual variables. Controlled indoor environmental techniques, as described in the current paper, may also be utilized in different types of experiments in malacology, and represent a substantial technical advance in malacological work.