An Attachable Electromagnetic Energy Harvester Driven Wireless Sensing System Demonstrating Milling-Processes and Cutter-Wear/Breakage-Condition Monitoring.

An attachable electromagnetic-energy-harvester driven wireless vibration-sensing system for monitoring milling-processes and cutter-wear/breakage-conditions is demonstrated. The system includes an electromagnetic energy harvester, three single-axis Micro Electro-Mechanical Systems (MEMS) accelerometers, a wireless chip module, and corresponding circuits. The harvester consisting of magnets with a coil uses electromagnetic induction to harness mechanical energy produced by the rotating spindle in milling processes and consequently convert the harnessed energy to electrical output. The electrical output is rectified by the rectification circuit to power the accelerometers and wireless chip module. The harvester, circuits, accelerometer, and wireless chip are integrated as an energy-harvester driven wireless vibration-sensing system. Therefore, this completes a self-powered wireless vibration sensing system. For system testing, a numerical-controlled machining tool with various milling processes is used. According to the test results, the system is fully self-powered and able to successfully sense vibration in the milling processes. Furthermore, by analyzing the vibration signals (i.e., through analyzing the electrical outputs of the accelerometers), criteria are successfully established for the system for real-time accurate simulations of the milling-processes and cutter-conditions (such as cutter-wear conditions and cutter-breaking occurrence). Due to these results, our approach can be applied to most milling and other machining machines in factories to realize more smart machining technologies.

Myocardial tissue Doppler-based indexes to distinguish right ventricular volume overload from right ventricular pressure overload.

The objective of this study was to develop tissue Doppler parameters that could be used to differentiate right ventricular (RV) volume overload from RV pressure overload. The RV-pressure-overload group consisted of 40 patients with severe pulmonary hypertension, and the RV-volume-overload group consisted of 40 patients who had an atrial septal defect without evidence of right-to-left shunt, significant pulmonary hypertension, or Eisenmenger's complex. Another 40 healthy subjects were enrolled and served as a control group. Routine echocardiography and tissue Doppler imaging were performed. RV myocardial performance index was determined based on data collected during tissue Doppler imaging over the lateral tricuspid annulus. In patients with RV pressure overload, tissue Doppler parameters showed characteristically lower systolic velocity over the tricuspid annulus (RV myocardial systolic wave [Sm]) and longer isovolumic relaxation time (RV-IVRT). Nevertheless, in patients with RV volume overload, RV-Sm increased significantly, but early-diastolic velocity over tricuspid annulus was relatively low. In conclusion, RV-MPI, RV-Sm/early-diastolic velocity over tricuspid annulus, and RV-IVRT/RV-Sm were all useful to differentiate RV pressure overload from volume overload, although RV-IVRT/RV-Sm was the best parameter, with excellent sensitivity and specificity.

Usefulness of regional myocardial performance index to diagnose pulmonary embolism in patients with echocardiographic signs of pulmonary hypertension.

In this study, myocardial performance index (MPI) was used to identify pulmonary embolism (PE) in patients with echocardiographic signs of pulmonary hypertension. One hundred patients with echocardiographic signs of pulmonary hypertension were enrolled in this study after informed consent was obtained. All patients underwent multidetector-row computed tomography of the chest, and PE was found in 50 patients. Another 100 patients without any cardiopulmonary distress or echocardiographic signs of pulmonary hypertension served as the control group. All cohorts were enrolled after the exclusion of (1) any rhythm other than sinus rhythm; (2) complete bundle branch block; (3) ischemic heart disease proved by stress test, perfusion scan, or coronary angiography; (4) a left ventricular (LV) ejection fraction <50%; and (5) inadequate echocardiograms. Routine echocardiography and tissue Doppler imaging were performed, including the MPIs of the right and left ventricles. The right ventricular (RV) MPI was significantly higher in patients with PE than in others (p <0.0001). Patients without PE had concordant changes in the RV and LV MPIs. In patients with acute PE, the RV MPI became higher, but the LV MPI was relatively constant. Using the RV MPI divided by the LV MPI (the V index), PE could be distinguished in patients with echocardiographic signs of pulmonary hypertension. By receiver-operating characteristic curve analysis, the V index >1.2 identified PE with sensitivity of 82% and specificity of 83%. In conclusion, the V index is a useful parameter to assess the possibility of PE in patients with echocardiographic signs of pulmonary hypertension.

Major events in uremic patients: insight from parameters derived by flow propagation velocity.

BACKGROUND: The parameters derived by flow propagation velocity (FPV) of early-diastolic mitral inflow have been proved to be associated with cardiovascular risk. This study was undertaken to analyze the prognosis of uremic patients by FPV. METHODS: A total of 100 uremic patients were enrolled. All patients underwent conventional echocardiographic examination and FPV measurement. Those examinations were performed before and after hemodialysis (within 30 minutes). Patients were followed for 4 years. Major events were recorded and defined as any-cause mortality and nonfatal cardiovascular events with hospitalization. Patients were separated into two groups according to a post-dialytic E/FPV of <1.5 or > or =1.5 (early-diastolic velocity of mitral inflow divided by FPV). RESULTS: Twenty-six major events were recorded, including 13 cases with mortality and 13 cases with nonfatal cardiovascular events. The patients with a post-dialytic E/FPV of > or =1.5 had a higher prevalence of underlying coronary arterial disease (30% vs. 17%), left ventricular systolic dysfunction (left ventricular ejection fraction: 46% +/- 10% vs. 52% +/- 8%), and a major event. By Cox regression analysis, a post-dialytic E/FPV of > or =1.5 (hazard ratio 2.358, 95% confidence interval 1.118-4.62, P = .008) was the strongest independent factor to predict the major events, after adjustment of other covariates. CONCLUSION: A post-dialytic E/FPV of > or =1.5 predicts higher adverse events in uremic patients.

Right heart function in systemic lupus erythematosus: insights from myocardial Doppler tissue imaging.

The purpose of this study was to use Doppler tissue imaging to evaluate heart function and to investigate the correlation between Doppler imaging and pulmonary artery systolic pressure (PASP) and right ventricular (RV) ejection fraction (EF) in patients with systemic lupus erythematosus (SLE). Standard echocardiography and 2-dimensional and color Doppler imaging were used to assess cardiac function in patients given the diagnosis of SLE (n = 40) and healthy control subjects (n = 45). Half of the patients with SLE also presented with pulmonary hypertension (PH). Significant differences in PASP and RV EF (RVEF) were found between the control and SLE groups. The peak systolic velocity of tricuspid annulus was significantly lower in patients with SLE than in the control group. The calculated myocardial performance index of the RV, septum, and left ventricular lateral wall were significantly higher in patients with SLE than in the control group. Bivariate correlation analysis revealed a significant correlation among PASP, RVEF, and systolic tricuspid annular velocity. There was a significant correlation between each of these 3 parameters and the 6-minute walk distance in patients with SLE. Patients with SLE and PH had a significantly shorter 6-minute walk distance than patients with SLE without PH. Furthermore, in patients with SLE and PH, RVEF and systolic tricuspid annular velocity were lower than in the control subjects and patients with SLE without PH. Patients with SLE and PH had a longer isovolumic relaxation time and a higher myocardial performance index of RV than those without PH. Finally, by simple linear regression analysis, we found a significant positive relation between RVEF and systolic tricuspid annular velocity, but a negative relationship between PASP and systolic tricuspid annular velocity. These findings demonstrate that in patients with SLE, systolic tricuspid annular velocity determined by echocardiography and Doppler imaging can be used to assess RV function and PASP. Furthermore, systolic tricuspid annular velocity reflects exercise tolerance in patients with SLE and the length of the isovolumic relaxation time represents the progression of PH.

Severe tricuspid regurgitation shows significant impact in the relationship among peak systolic tricuspid annular velocity, tricuspid annular plane systolic excursion, and right ventricular ejection fraction.

OBJECTIVES: Peak systolic mitral annular velocities correlate with left ventricular ejection fraction (EF) regardless of mitral regurgitation severity. Peak systolic tricuspid annular velocity (RV-Sm) and tricuspid annular plane systolic excursion (TAPSE) are used to assess right ventricular (RV) EF (RVEF). We investigated whether tricuspid regurgitation (TR) affects the relationship among RV-Sm, TAPSE, and RVEF. METHODS: Patients (n = 625) underwent echocardiography and Doppler tissue studies. Left ventricular EF and RVEF were estimated by Simpson's rule. Because of confounding, we excluded patients with diseases that influence mitral annular motion or left ventricular function. We finally enrolled 225 patients: 125 with mild TR, 50 with moderate TR, and 50 with severe TR. Forty study patients (20 with mild TR, 10 with moderate TR, and 10 with severe TR) received radionuclide ventriculography. RESULTS: The RVEF estimated by Simpson's method correlated strongly to that estimated by the radionuclide method (r = 0.793, r2 = 0.629, P < .0001). With mild or moderate TR, RV-Sm correlated well to RVEF (mild TR group: r = 0.765, r2 = 0.59, P < .0001; moderate TR group: r = 0.756, r2 = 0.57, P < .0001). RV-Sm had no significant correlation to RVEF in patients with severe TR (r = 0.212, r2 = 0.05, P = .167). Over a range of TR severities, the relationship between TAPSE and RVEF showed a similar trend to that between RV-Sm and RVEF. CONCLUSION: Severe TR has a significant impact on the relationship between RV-Sm and RVEF and between TAPSE and RVEF. TAPSE and RV-Sm in patients with severe TR show poor correlation to RVEF. When applying Doppler tissue method or TAPSE to assess RV function, severe TR is a significantly confounding factor.