A high performance biometric signal and image processing method to reveal blood perfusion towards 3D oxygen saturation mapping ABSTRACTNon-contact imaging photoplethysmography (PPG) is a recent development in the field of physiological data acquisition, currently undergoing a large amount of research to characterize and define the range of its capabilities. Contact-based PPG techniques have been broadly used in clinical scenarios for a number of years to obtain direct information about the degree of oxygen saturation for patients. With the advent of imaging techniques, there is strong potential to enable access to additional information such as multi-dimensional blood perfusion and saturation mapping. The further development of effective opto-physiological monitoring techniques is dependent upon novel modelling techniques coupled with improved sensor design and effective signal processing methodologies. The biometric signal and imaging processing platform (bSIPP) provides a comprehensive set of features for extraction and analysis of recorded iPPG data, enabling direct comparison with other biomedical diagnostic tools such as ECG and EEG. Additionally, utilizing information about the nature of tissue structure has enabled the generation of an engineering model describing the behaviour of light during its travel through the biological tissue. This enables the estimation of the relative oxygen saturation and blood perfusion in different layers of the tissue to be calculated, which has the potential to be a useful diagnostic tool.Keywords: imaging photoplethysmography, pulse oximetry, oxygen saturation mapping, signal acquisition and processing. *S.Hu@lboro.ac.uk; phone +44 1509 227059 INTRODUCTIONImaging photoplethysmography (iPPG) is one of the emerging medical imaging technologies to visualize peripheral blood perfusion in a specific tissue. Different from other optical related technologies, i.e., laser Doppler [1, 2] and Speckle imaging [3], iPPG aims to detect the dynamic change of blood volume in a designated tissue area rather than blood velocity and flow. Besides, iPPG can provide other human vital bioinformatics such as heart rate variability (HRV) [4] and pulse transit time (PTT) [5]. iPPG has significant priority over to the conventional PPG, as removes the primary limitations of spot measurement and contact sensory. iPPG can also monitor these vital human signs on different parts of skin surface simultaneously and bring the possible new insights that might come from hemodynamic mapping even 3D oxygen saturation in the tissue segments.Non-contact camera based iPPG has been well established with the visualization of blood perfusion [6], which demonstrated the simultaneous capture of PPG waveforms from the extremities at three wavelengths (660 nm, 840 nm and 905 nm) in both transmission and reflection modes. Another work has reported a reflection mode capture of 'heart cycle-related' pulsatile variations using a CMOS camera [7], with its illumination at 660 nm, 810 nm, and 940 nm. An additional research s...
International audienceCell behaviour during epithelial to mesenchymal transition (EMT) was simulated using the cellular Potts formalism in Compucell3D. A recent in vitro study revealed that the mechanism of endocardial scattering can be induced independently of invasion into the extracellular matrix (ECM). This suggests that loss of endocardial cohesion alone is not sufficient for full EMT. The 3D simulations, which take account of changes in adhesion, match this conclusion. The principle by which the rate of mitosis regulates the endocardial monolayer was demonstrated; suggesting a route by which VEGF might regulate EMT
A model of the lysis-lysogeny decision cycle of the Phage-λ virus has been re-implemented using standard engineering tools. The model is based on previous systems biology-based work and is constructed using the biological knowledge of the protein signalling networks within the virus. It explores how the emergent effects from the protein interactions produce the observed lysis-lysogeny behaviour. The software tools used (LabVIEW TM and MATLAB TM ) were chosen as they do not require specialised biochemical knowledge and have a wide industrial user base. This modelling is done as part of Project Fallot at Loughborough University, which is producing multiscale models of congenital heart disease. Part of this research requires a model of Delta-Notch protein signalling. Comment is made on the applications of the implemented modelling technique for modelling of Delta Notch protein signalling in cells.
Cell behavior during endocardial to mesenchymal transition (EMT) was simulated using the cellular Potts formalism in Compucell 3D. The processes of loss of endocardial cohesion and invasion into the extracellular matrix (ECM) were stimulated by changing surface energy parameters. The simulations match in vitro results which suggest that endocardial motility on the surface of collagen gel can be induced separately from 3D invasion of the gel, via Notch signaling in the absence of BMP2. A principle by which the rate of mitosis would regulate the monolayer was demonstrated; suggesting a route for Vascular Endothelial Growth Factor (VEGF) control of EMT. A conceptual model of the system of protein interactions during EMT was assembled from multiple studies. A route for subcellular models to be formalized as Systems Biology Markup Language (SBML) differential equations is indicated. Scale linking would be achieved through Compucell 3D periodically integrating the SBML models for each cell during a simulation run, and updating parameters for protein concentrations assigned to individual cells. The surface energy parameters for the cells would be recalculated at each step from their simulated protein concentrations. Such scale linking opens up the potential for complexity to be gradually introduced, while maintaining experimental validation.
This paper provides a first description of a multiscale systems modeling approach applied to the congenital birth defect known as the tetralogy of Fallot. The multiscale approach adopted owes a lot to the effort of the world-wide physiome consortium and the work of research groups within the European Union on the Virtual Physiological Human. Both a spatial scale and time scale are used to establish the systems boundaries of the application. The tetralogy of Fallot includes up to four simultaneously occurring anatomic abnormalities that underpin the defect. The use of finite state machines and cellular automata pave the way to understand the processes in time and space that contribute to the defect.
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