Mitral Annulus Calcification is associated with valvular and cardiac structural abnormalities

Abstract Introduction Mitral annulus calcification (MAC) is a common finding on echocardiographic examination. The goal of this study was to evaluate associations between MAC and cardiac abnormalities using a large echocardiographic database. Methods For this study we retrospectively reviewed 24,380 echocardiograms performed for clinical reasons between the years 1984 and 1998. Results MAC was reported in 1,494 (6.1%) subjects. Using multivariate analysis, age, left ventricular hypertrophy (LVH), mitral regurgitation (MR), tricuspid regurgitation (TR), aortic stenosis (AS), left atrial (LA) enlargement and reversed E/A ratio were independently associated with MAC.)MAC was noted in 11.7 % of patients with MR vs. 4.3% without MR (OR: 2.0, CI 1.6–2.6, p Conclusion In our study, MAC independently correlated with significant structural heart abnormalities. This suggests that identification of MAC may serve as a marker for other cardiac structural disorders.</p

Intelligent speed control of hybrid stepper motor considering model uncertainty using brain emotional learning

This paper presents an implementation of the brain emotional learning-based intelligent controller (BELBIC) for precise speed tracking of the hybrid stepper motor (HSM). Such a configuration is applicable where high resolution and accuracy is essential particularly in uncertain conditions. The proposed controller is a model-free controller independent of the model dynamics and variations that occur in a system. It is capable of autolearning to handle unforeseen disturbances. To evaluate the performance of the BELBIC controller in realistic conditions, the uncertainty of the system as a result of mechanical parameter variation and load torque disturbance is considered. To verify an excellent dynamic performance and the feasibility of the BELBIC, the system is simulated in MATLAB Simulink, and the results of the simulation are compared with an optimized proportional integral (PI) controller. The simulation results confirm the superior performance of the BELBIC for fast and precise speed response as well as its potential in dealing with nonlinearity and uncertainty handling as compared with that of the PI controller. The proposed controller is used in realistic applications, such as tunable-laser system and robot-assisted surgery