Neurohumoral,cardiac and inflammatory markers in the evaluation of heart failure severity and progression

Heart failure is common in adult population,accounting for substantial morbidity and mortality worldwide.The main risk factors for heart failure are coronary artery disease,hypertension,obesity,diabetes mellitus,chronic pulmonary diseases,family history of cardiovascular diseases,cardiotoxic therapy.The main factor associated with poor outcome of these patients is constant progression of heart failure.In the current review we present evidence on the role of established and candidate neurohumoral biomarkers for heart failure progression management and diagnostics.A growing number of biomarkers have been proposed as potentially useful in heart failure patients,but not one of them still resembles the characteristics of the"ideal biomarker."A single marker will hardly perform well for screening,diagnostic,prognostic,and therapeutic management purposes.Moreover,the pathophysiological and clinical significance of biomarkers may depend on the presentation,stage,and severity of the disease.The authors cover main classification of heart failure phenotypes,based on the measurement of left ventricular ejection fraction,including heart failure with preserved ejection fraction,heart failure with reduced ejection fraction,and the recently proposed category heart failure with mid-range ejection fraction.One could envisage specific sets of biomarker with different performances in heart failure progression with different left ventricular ejection fraction especially as concerns prediction of the future course of the disease and of left ventricular adverse/reverse remodeling.This article is intended to provide an overview of basic and additional mechanisms of heart failure progression will contribute to a more comprehensive knowledge of the disease pathogenesis.

System failure analysis based on DEMATEL–ISM and FMECA

A new method of system failure analysis was proposed. First, considering the relationships between the failure subsystems,the decision making trial and evaluation laboratory(DEMATEL) method was used to calculate the degree of correlation between the failure subsystems, analyze the combined effect of related failures, and obtain the degree of correlation by using the directed graph and matrix operations. Then, the interpretative structural modeling(ISM) method was combined to intuitively show the logical relationship of many failure subsystems and their influences on each other by using multilevel hierarchical structure model and obtaining the critical subsystems. Finally, failure mode effects and criticality analysis(FMECA) was used to perform a qualitative hazard analysis of critical subsystems, determine the critical failure mode, and clarify the direction of reliability improvement.Through an example, the result demonstrates that the proposed method can be efficiently applied to system failure analysis problems.

Finite element analysis of steep excavation slope failure by CFS theory

The distribution of Coulomb failure stress （CFS） change in the steep excavation slope is calculated by finite element method in this paper, and the failure mechanics under different conditions have been investigated. Comparing the CFSs before and after the slope excavation （stress loading and unloading processes）, the dangerous internal zone and the most likely failure external area are attained. Given the shear cracks on the top surface while tensile stress or cracks along the toe of the slope, we analyze the high cutting-angle steep slope in Kaixian county of the Three Gorges Reservoir region. We bring forward that the peak value of CFS after excavation can reach to the order of 0.1 MPa, which is greatly higher than that of before. Our preliminary results are useful for optimizing the reinforcement structure during the steep slope stabilization engineering.

Failure Analysis of Power Electronic Devices and Their Applications under Extreme Conditions

Power electronic devices are the core components of modern power converters,not only for normal applications,but also for extreme conditions.Current design of power electronic devices require large redundancies for reliability.This results in huge volume and weight for a large-capacity power converter,especially for some extreme applications.Therefore,to optimize the power density,the reliability of power devices needs to be investigated first in order to obtain the accurate operational margin of a power device.Although much research on device failure analysis has been reported,there still lacks efficient failure evaluation methods.This paper first summarizes the current failure research.Then,a three-step failure analysis method of power electronic devices is proposed as:failure information collection,failure identification and mechanism,and failure evaluation.The physics-based modeling method is emphasized since it has a strong relationship with the device fundamentals.After that,power electronic device applications under extreme conditions are introduced and a design method of device under extreme conditions is proposed based on the thermal equilibrium idea.Finally,the challenges and prospects to improve the power device reliability under extreme conditions are concluded.