17 resultados para Failure assessment

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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Structural durability is an important design criterion, which must be assessed for every type of structure. In this regard, especial attention must be addressed to the durability of reinforced concrete (RC) structures. When RC structures are located in aggressive environments, its durability is strongly reduced by physical/chemical/mechanical processes that trigger the corrosion of reinforcements. Among these processes, the diffusion of chlorides is recognized as one of major responsible of corrosion phenomenon start. To accurate modelling the corrosion of reinforcements and to assess the durability of RC structures, a mechanical model that accounts realistically for both concrete and steel mechanical behaviour must be considered. In this context, this study presents a numerical nonlinear formulation based on the finite element method applied to structural analysis of RC structures subjected to chloride penetration and reinforcements corrosion. The physical nonlinearity of concrete is described by Mazars damage model whereas for reinforcements elastoplastic criteria are adopted. The steel loss along time due to corrosion is modelled using an empirical approach presented in literature and the chloride concentration growth along structural cover is represented by Fick's law. The proposed model is applied to analysis of bended structures. The results obtained by the proposed numerical approach are compared to responses available in literature in order to illustrate the evolution of structural resistant load after corrosion start. (C) 2014 Elsevier Ltd. All rights reserved.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Prolonged intermittent renal replacement therapy (PIRRT) has emerged as an alternative to continuous renal replacement therapy in the management of acute kidney injury (AKI) patients. This trial aimed to compare the dialysis complications occurring during different durations of PIRRT sessions in critically ill AKI patients. We included patients older than 18 years with AKI associated with sepsis admitted to the intensive care unit and using noradrenaline doses ranging from 0.3 to 0.7 mu g/kg/min. Patients were divided into two groups randomly: in G1, 6-h sessions were performed, and in G2, 10-h sessions were performed. Seventy-five patients were treated with 195 PIRRT sessions for 18 consecutive months. The prevalence of hypotension, filter clotting, hypokalemia, and hypophosphatemia was 82.6, 25.3, 20, and 10.6%, respectively. G1 was composed of 38 patients treated with 100 sessions, whereas G2 consisted of 37 patients treated with 95 sessions. G1 and G2 were similar in male predominance (65.7 vs. 75.6%, P=0.34), age (63.6 +/- 14 vs. 59.9 +/- 15.5 years, P=0.28) and Sequential Organ Failure Assessment score (SOFA; 13.1 +/- 2.4 vs. 14.2 +/- 3.0, P=0.2). There was no significant difference between the two groups in hypotension (81.5 vs. 83.7%, P=0.8), filter clotting (23.6 vs. 27%, P=0.73), hypokalemia (13.1 vs. 8.1%, P=0.71), and hypophosphatemia (18.4 vs. 21.6%, P=0.72). However, the group treated with sessions of 10h were refractory to clinical measures for hypotension, and dialysis sessions were interrupted more often (9.5 vs. 30.1%, P=0.03). Metabolic control and fluid balance were similar between G1 and G2 (blood urea nitrogen [BUN]: 81 +/- 30 vs. 73 +/- 33mg/dL, P=1.0; delivered Kt/V: 1.09 +/- 0.24 vs. 1.26 +/- 0.26, P=0.09; actual ultrafiltration: 1731 +/- 818 vs. 2332 +/- 947mL, P=0.13) and fluid balance (-731 +/- 125 vs. -652 +/- 141mL, respectively) . In conclusion, intradialysis hypotension was common in AKI patients treated with PIRRT. There was no difference in the prevalence of dialysis complications in patients undergoing different durations of PIRRT.

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OBJECTIVE: To assess the hemodynamic and vasodilating effects of milrinone lactate (ML) in patients with dilated cardiomyopathy (DCM) and New York Heart Association (NYHA) class III and IV heart failure. METHODS: Twenty patients with DCM and NYHA class III and IV heart failure were studied. The hemodynamic and vasodilating effects of ML, administered intravenously, were evaluated. The following variables were compared before and during drug infusion: cardiac output (CO) and cardiac index (CI); pulmonary capillary wedge pressure (PCWP); mean aortic pressure (MAP); mean pulmonary artery pressure (MPAP); mean right atrial pressure (MRAP); left ventricular systolic and end-diastolic pressures (LVSP and LVEDP, respectively); peak rate of left ventricular pressure rise (dP/dt); systemic vascular resistance (SVR); pulmonary vascular resistance (PVR); and heart rate (HR). RESULTS: All patients showed a significant improvement of the analysed parameters of cardiac performance with an increase of CO and CI; a significant improvement in myocardial contractility (dP/dt) and reduction of the LVEDP; PCWP; PAP; MAP; MRAP; SVR; PVR. Were observed no significant increase in HR occurred. CONCLUSION: Milrinone lactate is an inotropic dilating drug that, when administered intravenously, has beneficial effects on cardiac performance and myocardial contractility. It also promotes reduction of SVR and PVR in patients with DCM and NYHA class III and IV of heart failure.

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OBJECTIVE: To evaluated the clinical diagnostic, efficiency for basic death causes in patients dying of circulatory disease and de relative frequency of those diseases. METHODS: Analysis of medical record data of 82 patients, ages from 16 to 84 years old (68 over 40 years old), whose died of circulatory disease and had undergone necropsy in the period from 1988 to 1993 years in the University Hospital of Medicine Faculty of Botucatu-UNESP, Br. RESULTS: The functional class of patients were III or IV, in 78%, and 81.7% needed urgent hospitalization. By the clinical judgment the death were by ischemic heart disease in 32 (21 acute myocardial infarction), Chagas'disease in 12, valvopathy in 11, cardiomyopathy in 7, heart failure with no specification of cardiopathy in 11 and other causes in 9. At the necropsy the death cause was ischemic heart disease in 34 patients, valvopathy in 10, Chagas'disease in 10, cardiomyopathy in 5, and heart failure with no specification of cardiopathy in 2.The concordance taxes were in thhe same order: 94,6%, 90,0%, 83.3%, 71.4% and 28.5%. CONCLUSION: There was a great efficiency of clinical diagnosis for death cause in a general university hospital. The ischemic heart disease were the main causes of death.

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In 2010, an accident occurred in Americana-SP, Brazil, involving two trains and one bus on a Grade Crossing, when 10 people died and 17 were injured including workers. This paper aims to analyze the accident using the Model of Analysis and Prevention of Work Accidents (MAPA). The method provides observation of work, interviews and analysis of documents to understand precedents of the event in the following stages: to understand the usual work from the involved people, the changes occurred in the system, the operation of barriers, managerial and organizational aspects. By the end, measures are suggested to avoid new occurrences. The accident took place at night in a site with insufficient lighting. The working conditions of bus drivers, train operators and watchmen are inadequate. There were only symbolic barriers (visual and acoustic signals) triggered manually by watchman upon train operator radio communication. The fragility of the barrier system associated to poor lighting and short time to trigger the signaling seem to play a critical role in the event. Contrary to the official report which resulted in guilt of the bus driver, the conclusion of the paper emphasizes the fragility of the safety system and the need of level crossing reproject.

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Objective To assess the brachial plexus block in chickens by an axillary approach and using a peripheral nerve stimulator.Study design Prospective, randomized, double-blinded study.Animals Six, 84-week old, female chickens.Methods Midazolam (1 mg kg(-1)) and butorphanol (1 mg kg(-1)) were administered into the pectoralis muscle. Fifteen minutes later, the birds were positioned in lateral recumbency and following palpation of the anatomic landmarks, a catheter was inserted using an axillary approach to the brachial plexus. Lidocaine or bupivacaine (1 mL kg(-1)) was injected after plexus localization by the nerve stimulator. Sensory function was tested before and after blockade (carpus, radius/ulna, humerus and pectoralis muscle) in the blocked and unblocked wings. The latency to onset of motor and sensory block and the duration of sensory block were recorded. A Friedman nonparametric one-way repeated-measures ANOVA was used to compare scores from baseline values over time and to compare the differences between wings at each time point.Results A total of 18 blocks were performed with a success rate of 66.6% (12/18). The latency for motor block was 2.8 +/- 1.1 and 3.2 +/- 0.4 minutes for lidocaine and bupivacaine, respectively. The latencies for and durations of the sensory block were 6.0 +/- 2.5 and 64.0 +/- 18.0 and 7.8 +/- 5.8 and 91.6 +/- 61.7 minutes for lidocaine and bupivacaine, respectively. There was no statistical difference between these times for lidocaine or bupivacaine. Sensory function was not abolished in nonblocked wings.Conclusions and clinical relevance The brachial plexus block was an easy technique to perform but had a high failure rate. It might be useful for providing anesthesia or postoperative analgesia of the wing in chickens and exotic avian species that have similar wing anatomy.

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The risk for venous thromboembolism (VTE) in medical patients is high, but risk assessment is rarely performed because there is not yet a good method to identify candidates for prophylaxis. Purpose: To perform a systematic review about VTE risk factors (RFs) in hospitalized medical patients and generate recommendations (RECs) for prophylaxis that can be implemented into practice. Data sources: A multidisciplinary group of experts from 12 Brazilian Medical Societies searched MEDLINE, Cochrane, and LILACS. Study selection: Two experts independently classified the evidence for each RF by its scientific quality in a standardized manner. A risk-assessment algorithm was created based on the results of the review. Data synthesis: Several VTE RFs have enough evidence to support RECs for prophylaxis in hospitalized medical patients (eg, increasing age, heart failure, and stroke). Other factors are considered adjuncts of risk (eg, varices, obesity, and infections). According to the algorithm, hospitalized medical patients ≥40 years-old with decreased mobility, and ≥1 RFs should receive chemoprophylaxis with heparin, provided they don't have contraindications. High prophylactic doses of unfractionated heparin or low-molecular-weight-heparin must be administered and maintained for 6-14 days. Conclusions: A multidisciplinary group generated evidence-based RECs and an easy-to-use algorithm to facilitate VTE prophylaxis in medical patients. © 2007 Rocha et al, publisher and licensee Dove Medical Press Ltd.

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Background: Ultrasound Doppler is a new technology that has recently been used in large animal reproduction. As the conventional ultrasound (B-mode) it is a noninvasive technique, but with the advantage of allows the assessment of the hemodynamic of reproductive tract in real time. The observation of important features of the vascularization and changes that occur during physiological processes that were not previously seen on B-mode encourage a reassessment of the concepts already established on the events of the reproductive physiology of animals and their applications. Review: In attempt to re-understand the equine reproductive physiology and finding practical uses to this new technique, authors showed that, during the follicular deviation, features are observed by Doppler before being observed under B-mode ultrasound like changes in the speed of the blood flow two days before deviation of the follicle size and one day before the increase in blood flow area of the follicular wall. According to another study ovulation is characterized by a decreased blood flow of the follicular wall in the last four hours preceding it, as well as the serration of the granulosa layer and formation of a non vascularized apex, but in our ongoing study, the ability to decrease the vascularity was not found. Very vascularized follicles are associated with higher rates of oocyte maturation and pregnant that does less vascularized follicles in the preovulatory phase. Those follicles that have septated evacuation (or prolonged) showed more vascularization and serration of the granulosa one hour before ovulation than follicles that ovulate normally, and this vascularization includes the apex of the follicle, the follicular wall portion that is not vascularized in normal ovulation. Another study reported that hemorrhagic follicles have better vascularization of the follicular wall on the days preceding ovulation than follicles destined to ovulate. Some authors also showed that anovulatory follicles grow in size at the same rate as ovulatory follicles, but the percentage of vascularization of its wall is much smaller at 35 mm. Another study characterized that the vascular wall of the follicle that results in the first ovulation of the year is much smaller on the day before ovulation than the number of vessels present in a follicle that will ovulate in the middle of the breeding season. In these cases, the use of Doppler ultrasound can help to prevent economic losses as insemination of mares in cycles that are not able of resulting in pregnancy. This review aims to gather the information found in the literature about the characteristics of follicular hemodynamic of mares taking into account moments of deviation in follicle size, ovulation, ovulation failure and follicular viability. Conclusion: The Doppler technology has the potential to provide important information about the follicular environment and thus be used in practice in search of the perfect equine reproductive management, achieving better utilization of genetic material and increasing the financial return. The use of this new tool opens a large area for several interesting studies that will contribute to the knowledge of the physiological events of the mare for that this technique can soon be effectively applied.

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The growth of maritime transport and oil exploitation activities may increase the risk of oil spills. Thus, plans and actions to prevent or mitigate impacts are needed to minimize the effects caused by oil. However, tools used worldwide to support contingency plans have not been integrated, thus leading to failure in establishing priority areas. This investigation aimed to develop indices of environmental vulnerability to oil (IEVO), by combining information about environmental sensibility to oil and results of numerical modeling of spilled oil. To achieve that, a case study concerning to oil spills scenarios in a subtropical coastal area was designed, and IEVOs were calculated and presented in maps, in order to make the information about the areas' vulnerability more easily visualized. For summer, the extension of coastline potentially affected by oil was approximately 150. km, and most of the coastline presented medium to high vulnerability. For winter, 230. km coastline would be affected, from which 75% were classified as medium to high vulnerability. Thus, IEVO maps allowed a rapid and clearer interpretation of the vulnerability of the mapped region, facilitating the planning process and the actions in response to an oil spill. © 2013 Elsevier Ltd.

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Objectives To consensually validate the operational definitions of the nursing diagnoses activity intolerance, excessive fluid volume, and decreased cardiac output in patients with decompensated heart failure. Method Consensual validation was performed in two stages: analogy by similarity of defining characteristics, and development of operational definitions and validation with experts. Results A total of 38 defining characteristics were found. Operational definitions were developed and content-validated. One hundred percent of agreement was achieved among the seven experts after five rounds. Ascites was added in the nursing diagnosis excessive fluid volume. Conclusion The consensual validation improves interpretation of human response, grounding the selection of nursing interventions and contributing to improved nursing outcomes. Implications for Practice Support the assessment of patients with decompensated heart failure. Objetivos Realizar a validacAo consensual das definicoes operacionais dos diagnosticos de enfermagem Intolerancia a atividade, Volume de liquidos excessivo e Debito cardiaco diminuido em pacientes com insuficiencia cardiaca descompensada. Metodo ValidacAo consensual em duas etapas: Analogia de semelhanca das caracteristicas definidoras e desenvolvimento de definicoes operacionais e validacAo com expertst. Resultados Foram encontradas 38 caracteristicas definidoras para os diagnosticos de enfermagem. Suas definicoes operacionais foram desenvolvidas e seu conteudo validado. Os resultados mostram que houve 100% de concordancia entre os sete experts apos cinco rodada. As definicoes operacionais foram classificadas com base no nivel de concordanica. Ascite foi acrescentada ao diagnostico Volume de liquidos excessivo. ConclusAo A validacAo consensual melhora a interpretacAo das respostas humanas, embasando a selecAo de intervencoes de enfermagem e contribuindo para melhorar os resultados. Implicacoes Para A Pratica Apoio a avaliacAo dos pacientes com insuficiencia cardiaca descompensada.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Background: Ischemic acute kidney injury is a common occurrence in the perioperative period and in critical patients admitted to intensive care units. The reestablishment of blood supply may worsen injury through the ischemia-reperfusion (I/R) mechanism. We investigated the effect of dexmedetomidine on the kidneys of rats subjected to an experimental I/R model. Methods: 34 rats anesthetized with isoflurane was undergone right nephrectomy and randomly assigned to four groups: Control C (saline solution); Dexmedetomidine D (dexmedetomidine); Sham S (saline solution); Sham with Dexmedetomidine SD (dexmedetomidine). The serum levels of neutrophil gelatinase-associated lipocalin (NGAL) were measured at time-points T1 (following stabilization), T2 (ischemia), T3 (reperfusion), T4 (12 h after of I/R). The kidneys were subjected to histological examination. Results: The NGAL levels were significantly higher at T4 compared with T1. Upon histological examination, the left kidneys in groups C and D exhibited a similar extent of cell injury. Conclusion: The levels of NGAL did not indicate either protection against or worsening of kidney injury. Histological examination for acute tubular necrosis showed that dexmedetomidine did not protect the kidneys from I/R.

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Objectives. To compare three different designs for measuring the bond strength between Y-TZP ceramic and a composite material, before and after ceramic surface treatment, evaluating the influence of the size of the adhesive interface for each design.Methods. 'Macro'tensile, microtensile, 'macro'shear, microshear, 'macro'push-out, and micropush-out tests were carried out. Two Y-TZP surface treatments were evaluated: silanization (sil) and tribochemical silica coating (30 mu m silica-modified Al2O3 particles + silanization) (TBS). Failure mode analysis of tested samples was also performed. Results. Both the surface treatment and the size of the bonded interface significantly affected the results (p = 0.00). Regardless of the type of surface treatment, the microtensile and microshear tests had higher values than their equivalent "macro" tests. However, the push-out test showed the highest values for the "macro" test. The tensile tests showed the greatest variability in results. The tribochemical silica coating method significantly increased bond strength for all tests.Significance. Different test designs can change the outcome for Y-TZP/cement interfaces, in terms of mean values and reliability (variability). The 'micro'tests expressed higher bond strengths than their equivalent 'macro'tests, with the exception of the push-out test (macro > micro). (C) 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.