49 research outputs found

    Numerical Simulation of undular bore evolution with chezy friction, 2015

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    This paper studies and simulates numerically the evolution of undular bore under the effect of damping in the framework of the perturbed extended Korteweg-de Vries equation. Here, we consider Chezy frictional term to be the damping term in the perturbed extended Korteweg-de Vries equation. Numerical simulations show that under the influence of the friction, the undular bore with thick leading wave will transform into KdV-like solitary wave as the leading wave of the undular bore. The amplitude of the "thick" leading wave will remain the same for some time even though there is dissipation effect

    Predictors of high-cost hospitalization in the treatment of acute coronary syndrome in Asia: findings from EPICOR Asia.

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    BACKGROUND: The EPICOR Asia (long-tErm follow-uP of antithrombotic management patterns In acute CORonary syndrome patients in Asia) study (NCT01361386) was an observational study of patients hospitalized for acute coronary syndromes (ACS) enrolled in 218 hospitals in eight countries/regions in Asia. This study examined costs, length of stay and the predictors of high costs during an ACS hospitalization. METHODS AND RESULTS: Data for patients hospitalized for an ACS (n = 12,922) were collected on demographics, medical history, event characteristics, socioeconomic and insurance status at discharge. Patients were followed up at 6 weeks' post-hospitalization for an ACS event to assess associated treatment costs from a health sector perspective. Primary outcome was the incurring of costs in the highest quintile by country and index event diagnosis, and identification of associated predictors. Cost data were available for 10,819 patients. Mean length of stay was 10.1 days. The highest-cost countries were China, Singapore, and South Korea. Significant predictors of high-cost care were age, male sex, income, country, prior disease history, hospitalization in 3 months before index event, no dependency before index event, having an invasive procedure, hospital type and length of stay. CONCLUSIONS: Substantial variability exists in healthcare costs for hospitalized ACS patients across Asia. Of concern is the observation that the highest costs were reported in China, given the rapidly increasing numbers of procedures in recent years. TRIAL REGISTRATION: NCT01361386

    Clinical Outcomes and Predictors of Improved Left Ventricular Ejection Fraction in Heart Failure with Reduced Ejection Fraction due to Non-Ischemic Cardiomyopathy

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    Background: Left ventricular ejection fraction (LVEF) improvement is the cornerstone of LV reverse remodelling. It prognosticates heart failure with reduced ejection fraction (HFrEF). There is limited data on the clinical factors that predict LVEF improvement among non-ischemic cardiomyopathy (NICM) patients in Malaysia. Objective: To determine the 3-year outcomes and predictors of LVEF improvement in patients with (NICM) and HFrEF. Materials & Methods: We recruited patients with NICM and HFrEF (LVEF <40%) between 2016 and 2018. NICM was defined as HF with 1) normal coronary arteries or 2) any coronary artery stenosis not involving the proximal left anterior descending artery (LAD) and without transmural fibrosis in the LAD territory from cardiac magnetic resonance (CMR) imaging to account for the impaired LVEF. Clinical and imaging parameters were assessed using logistic regression statistics to determine the predictors of LVEF improvement. LVEF improvement is defined as a recovery of EF to > 40% with at least a 10-point increment from baseline. The clinical outcomes at three year were 1) change in NYHA class and 2) composite of all-cause mortality, unscheduled clinic or emergency department visits, readmission and/or ventricular arrhythmia. Results: 43 patients were recruited. The mean duration of follow-up and echocardiographic assessment interval were 46 and 23 months, respectively. The cohort had a mean age of 46±13 years, and were mostly male (72%). More patients had NYHA 1 at the end of the study (37% vs 86%). 11 patients (25%) recorded composite outcomes. 62.8% had LVEF improvement. Patients with LVEF improvement had a lower incidence of late gadolinium enhancement (51.7% vs 85.7%, odds 5.6 ,p=0.045) and midwall fibrosis on CMR (18.5% vs 62.5%, odds 7.3, p=0.003). LVEF improvement did not affect the functional NYHA recovery (92% vs 81%, p=0.28). Patients with less LVEF improvement had higher incidence of composite outcome (18.5% vs 37.5%, p=0.168). Other characteristics were not significantly different between the groups. Conclusion: Patients with NICM and LVEF improvement had lower composite outcome. Absence of late gadolinium enhancement, particularly midwall fibrosis was an independant predictor of LVEF improvement. This underscores the importance of CMR tissue characterisation to refine the prognostication of NICM patients

    From basic mechanisms to clinical applications in heart protection, new players in cardiovascular diseases and cardiac theranostics: meeting report from the third international symposium on "New frontiers in cardiovascular research"

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    In this meeting report, particularly addressing the topic of protection of the cardiovascular system from ischemia/reperfusion injury, highlights are presented that relate to conditioning strategies of the heart with respect to molecular mechanisms and outcome in patients' cohorts, the influence of co-morbidities and medications, as well as the contribution of innate immune reactions in cardioprotection. Moreover, developmental or systems biology approaches bear great potential in systematically uncovering unexpected components involved in ischemia-reperfusion injury or heart regeneration. Based on the characterization of particular platelet integrins, mitochondrial redox-linked proteins, or lipid-diol compounds in cardiovascular diseases, their targeting by newly developed theranostics and technologies opens new avenues for diagnosis and therapy of myocardial infarction to improve the patients' outcome

    Long-term antithrombotic management patterns in Asian patients with acute coronary syndrome: 2-year observations from the EPICOR Asia study.

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    BACKGROUND: Despite guideline recommendations, dual antiplatelet therapy (DAPT) is frequently used for longer than 1 year after an acute coronary syndrome (ACS) event. In Asia, information on antithrombotic management patterns (AMPs), including DAPT post discharge, is sparse. This analysis evaluated real-world AMPs up to 2 years post discharge for ACS. HYPOTHESIS: There is wide variability in AMP use for ACS management in Asia. METHODS: EPICOR Asia (NCT01361386) is a prospective observational study of patients discharged after hospitalization for an ACS in eight countries/regions in Asia, followed up for 2 years. Here, we describe AMPs used and present an exploratory analysis of characteristics and outcomes in patients who received DAPT for ≤12 months post discharge compared with >12 months. RESULTS: Data were available for 12 922 patients; of 11 639 patients discharged on DAPT, 2364 (20.3%) received DAPT for ≤12 months and 9275 (79.7%) for >12 months, with approximately 60% still on DAPT at 2 years. Patients who received DAPT for >12 months were more likely to be younger, obese, lower Killip class, resident in India (vs China), and to have received invasive reperfusion. Clinical event rates during year 2 of follow-up were lower in patients with DAPT >12 vs ≤12 months, but no causal association can be implied in this non-randomized study. CONCLUSIONS: Most ACS patients remained on DAPT up to 1 year, in accordance with current guidelines, and over half remained on DAPT at 2 years post discharge. Patients not on DAPT at 12 months are a higher risk group requiring careful monitoring

    Functional roles of fibroblast growth factor receptors (FGFRs) signaling in human cancers

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    Various interaction patterns of free-surface flow over multiple bumps at the bottom topography

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    The free-surface flow generated by multiple bumps at the bottom topography in a rectangular channel was considered, in the framework of the forced Korteweg-de Vries (fKdV) equation. The fKdV equationwill be solved numerically using pseudo-spectral method as an analytical solution could not be obtained due to the presence of forcing term and broken symmetry. Various interaction patterns of solitary waves with certain parameter regimes were observed and presented in various graphical forms. Interesting interaction patterns of the collision between uniformly forced solitons will provide us with a better understanding of the hindrance caused by multiple bumps at the uneven bottom topography and it will have a high impact on the water flow in a rectangular channel with uneven bottom topography

    Numerical solution of the gardner equation

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    The Gardner equation is commonly used to describe wave propagation in weakly nonlinear dispersive medium. The Gardner equation has a higher order nonlinear term, which could make the numerical calculation inaccurate. In this paper, the Gardner equation is solved using two numerical methods, i.e., the method of lines and pseudospectral method. The efficiency and accuracy of both methods were studied. Our results show that both methods are accurate and efficient methods to solve the Gardner equation. By comparing the accuracy of both the methods, the method of lines performs better than pseudospectral method most of the time

    Dynamic simulation of unrestrained interlocking Tuned Liquid Damper blocks

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    The objective of the study is to develop a new construction material as an alternative for expensive dampers. A Tuned Liquid Damper (TLD) system that is cast in a concrete masonry unit has been proposed. The block has been examined in its individual characteristics to consider the resonant effect of the building subjected to a wide range of water depth, d w , from 5 mm to 80 mm. The TLD block was designed to internal dimensions of 190 mm (length) × 60 mm (width) × 90 mm (height) in accordance to the Uniform Building Code (UBC) and Eurocode 8. Sine-sweep responses results were plotted in transmissibility ratio, u t /u g to frequency ratio, ω/ω n . The block at a depth of d w was simulated and empirically calculated. Tests for d w of 50 mm, 60 mm, and 70 mm have verified the fundamental frequency, f n , to be similar with the simulated and calculated eigenvalues. Further study of the combined structural model and TLD blocks test as a system has been compared with the numerical simulations. The results varied by approximately 2%. The system has recorded reduction of responses immediately at the test of d w , 5–80 mm. Optimum performance has been recorded at 60 mm. The test results employed half-power bandwidth to obtain the damping ratio. The damping has been contributed by both viscous damping component and inertia of the moving water body. The Rayleigh stiffness damping component has not been identified to participate in the forced excitation performance reduction. It was found that the new innovative block with tuned liquid can significantly increase the damping characteristics. Hence, the research is necessary to propose an alternative new construction material to withstand earthquake and wind disasters on buildings
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