The risk for left ventricular (LV) suction while maintaining adequate perfusion over a range of physiologic conditions during continuous flow LV assist device (LVAD) support is a significant clinical concern. To address this challenge, we developed a suction prevention and physiologic control (SPPC) algorithm for use with axial and centrifugal LVADs. The SPPC algorithm uses two gain-scheduled, proportional-integral controllers that maintain a differential pump speed (ΔRPM) above a user-defined threshold to prevent LV suction, while maintaining an average reference differential pressure (ΔP) between the LV and aorta to provide physiologic perfusion. Efficacy and robustness of the proposed algorithm were evaluated in silico during simulated rest and exercise test conditions for (1) ΔP/ΔRPM excessive setpoint (ES); (2) rapid eightfold increase in pulmonary vascular resistance (PVR); and (3) ES and PVR. Hemodynamic waveforms (LV pressure and volume; aortic pressure and flow) were simulated and analyzed to identify suction event(s), quantify total flow output (pump + cardiac output), and characterize the performance of the SPPC algorithm. The results demonstrated that the proposed SPPC algorithm prevented LV suction while maintaining physiologic perfusion for all simulated test conditions, and warrants further investigation in vivo.
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http://dx.doi.org/10.1097/MAT.0000000000000152 | DOI Listing |
Comput Med Imaging Graph
December 2024
Department of Radiology, The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong, China. Electronic address:
Automatic segmentation of breast terminal duct lobular units (TDLUs) on histopathological whole-slide images (WSIs) is crucial for the quantitative evaluation of TDLUs in the diagnostic and prognostic analysis of breast cancer. However, TDLU segmentation remains a great challenge due to its highly heterogeneous sizes, structures, and morphologies as well as the small areas on WSIs. In this study, we propose BreasTDLUSeg, an efficient coarse-to-fine two-stage framework based on multi-scale attention to achieve localization and precise segmentation of TDLUs on hematoxylin and eosin (H&E)-stained WSIs.
View Article and Find Full Text PDFISA Trans
December 2022
Equipment Management and Unmanned Aerial Vehicle Engineering College, Air Force Engineering University, Xi'an, 710051, China.
This paper proposes a sample entropy (SampEn) based prescribed performance controller (SPPC) for the longitudinal control of a supersonic tailless aircraft subject to model uncertainty and nonlinearity. Considering that SampEn can evaluate the system's stability, a SampEn-based feedback adjust system (SFAS) is developed in this paper. With the help of SFAS, the SPPC could identify the dangerous chattering in the status signal that may lead the aircraft to lose control and make appropriate adjustments to feedback.
View Article and Find Full Text PDFAdv Ther
March 2022
Department of Respiratory Medicine, Ghent University Hospital, 9000, Ghent, Belgium.
There are many different inhaler devices and medications on the market for the treatment of asthma and chronic obstructive pulmonary disease, with over 230 drug-delivery system combinations available. However, despite the abundance of effective treatment options, the achieved disease control in clinical practice often remains unsatisfactory. In this context, a key determining factor is the match or mismatch of an inhalation device with the characteristics or needs of an individual patient.
View Article and Find Full Text PDFASAIO J
May 2015
From the Department of Bioengineering and Cardiovascular and Thoracic Surgery, Cardiovascular Innovation Institute, University of Louisville, Louisville, Kentucky.
The risk for left ventricular (LV) suction while maintaining adequate perfusion over a range of physiologic conditions during continuous flow LV assist device (LVAD) support is a significant clinical concern. To address this challenge, we developed a suction prevention and physiologic control (SPPC) algorithm for use with axial and centrifugal LVADs. The SPPC algorithm uses two gain-scheduled, proportional-integral controllers that maintain a differential pump speed (ΔRPM) above a user-defined threshold to prevent LV suction, while maintaining an average reference differential pressure (ΔP) between the LV and aorta to provide physiologic perfusion.
View Article and Find Full Text PDFIEEE Trans Neural Netw
September 2010
Department of Computer Science, Nanjing University of Science and Technology, China.
This paper discusses the problem of what kind of learning model is suitable for the tasks of feature extraction for data representation and suggests two evaluation criteria for nonlinear feature extractors: reconstruction error minimization and similarity preservation. Based on the suggested evaluation criteria, a new type of principal curve-similarity preserving principal curve (SPPC) is proposed. SPPCs minimize the reconstruction error under the condition that the similarity between similar samples are preserved in the extracted features, thus giving researchers effective and reliable cognition of the inner structure of data sets.
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