12 research outputs found
Mode I Interlaminar Fracture Toughness Analysis of Co-Bonded and Secondary Bonded Carbon Fiber Reinforced Composites Joints
SHIFT IN HUMAN ROTAVIRUS DISTRIBUTION IN BELO HORIZONTE, BRAZIL DETECTED BY RIBONUCLEIC ACID ELECTROPHORESIS
Terapia da insuficiĂȘncia cardĂaca avançada ajustada por objetivos hemodinĂąmicos obtidos pela monitorização invasiva Advanced heart failure therapy adapted to hemodynamic objectives acquired from invasive hemodynamic monitoring
OBJETIVO: Avaliar o tratamento da insuficiĂȘncia cardĂaca (IC) avançada em relação Ă redução das pressĂ”es de enchimento ventricular, com a utilização de doses maiores de vasodilatadores, atravĂ©s da monitorização hemodinĂąmica invasiva. MĂTODOS: Foram estudados 19 pacientes com IC avançada, nos quais foi instalado o cateter de Swan-Ganz para guiar a administração de diurĂ©tico intravenoso (IV) e nitroprussiato de sĂłdio, com o objetivo de se reduzir de forma significativa as pressĂ”es de enchimento ventricular. Depois de alcançado esse objetivo ou 48 horas, foram introduzidas drogas orais atĂ© serem retirados os fĂĄrmacos venosos, mantendo o benefĂcio hemodinĂąmico. RESULTADOS: Dos 19 pacientes estudados, 16 (84%) eram do sexo masculino. A idade mĂ©dia foi de 66 ± 11,4 anos; a fração de ejeção mĂ©dia foi de 26 ± 6,3%; 2 pacientes (10,5%) apresentavam classe funcional (CF) III e 17 (89,5%), CF IV. Houve queda da pressĂŁo de oclusĂŁo da artĂ©ria pulmonar de 23 ± 11,50 mmHg para 16 ± 4,05 mmHg (p=0,008), do Ăndice de resistĂȘncia vascular sistĂȘmica de 3.023 ± 1.153,71 dynes/s/cm-5/mÂČ para 1.834 ± 719,34 dynes/s/cm-5/mÂČ (p=0,0001) e aumento do Ăndice cardĂaco de 2,1 ± 0,56 l/min/mÂČ para 2,8 ± 0,73 l/min/mÂČ (p=0,0003). Um subgrupo com hipovolemia foi identificado. CONCLUSĂO: Foi possĂvel reduzir as pressĂ”es de enchimento ventricular para valores significativamente menores, obtendo melhora significativa do Ăndice cardĂaco, do Ăndice de resistĂȘncia vascular sistĂȘmica e da pressĂŁo mĂ©dia da artĂ©ria pulmonar, utilizando-se doses significativamente maiores de vasodilatadores.<br>OBJECTIVE: To assess advanced heart failure (HF) treatment in relation to reduction of ventricular filling pressures, with the use of greater doses of vasodilators, through invasive hemodynamic monitoring. METHODS: Nineteen advanced HF patients were studied, in whom Swan-Ganz catheter was inserted to direct administration of diuretic intravenously (IV) and sodium nitroprusside, with the aim of significantly reduce ventricular filling pressures. After achieving such objective or 48 hours, oral drugs were introduced until venous medicines were removed, keeping hemodynamic benefit. RESULTS: From 19 patients studied, 16 (84%) were of male sex. The average age was 66 ± 11.4 years old; average ejection fraction was 26 ± 6.3%; 2 patients (10.5%) showed functional class (FC) III and 17 (89.5%), FC IV. There was a decrease of pulmonary artery occlusion pressure from 23 ± 11.50 mmHg to 16 ± 4.05 mmHg (p = 0.008), of systemic vascular resistance index from 3,023 ± 1,153.71 dynes/s/cm-5/mÂČ to 1,834 ± 719.34 dynes/s/cm-5/mÂČ (p = 0.0001) and an increase of cardiac index from 2.1 ± 0.56 l/min/mÂČ to 2.8 ± 0.73 l/min/mÂČ (p = 0.0003). A subgroup with hypovolemia was identified. CONCLUSION: It was possible to reduce ventricular filling pressures to significantly lower values, obtaining a significant improvement of cardiac index, systemic vascular resistance index and pulmonary artery mean pressure, by using significantly higher doses of vasodilators
Mode I Interlaminar Fracture Toughness Analysis of Co-Bonded and Secondary Bonded Carbon Fiber Reinforced Composites Joints
<div><p>Aiming to reduce aircraft weight, aeronautic industry seeks alternative materials and processes used to join its different structural parts. An option to traditional methods are high performance adhesive joints, which reduce weight, number of parts and component final cost, also resulting in higher strength structures. Although, the lack of experimental data to provide a detailed structural characterization of these joining techniques had limited their commercial application. The proposal of this work is to investigate the Mode I interlaminar fracture toughness under quasi-static loading using DCB specimens of carbon composite joints made by co-bonding and secondary bonding techniques, the latter giving more reliable results. For a better understanding on the failure in the systems, DSC and microscopy techniques were applied, from which three stages of delamination process during testing were observed: 1st Stage) Cohesive failure represented by an unstable crack propagation from a high energy level; 2nd Stage) transition from cohesive to adhesive and final intralaminar failure mode with lower energy levels than Stage 1; and 3rd Stage) completely stable propagation at low energy levels (delamination migrates from intralaminar to interlaminar, entirely in the substrate).</p></div