We describe a useful setting for interactive, real-time study of mathematical models of cardiac electrical activity, using implicit and explicit integration schemes implemented in JAVA. These programs are intended as a teaching aid for the study and understanding of general excitable media. Particularly for cardiac cell models and the ionic currents underlying their basic electrical dynamics. Within the programs, excitable media properties such as thresholds and refractoriness and their dependence on parameter values can be analyzed. In addition, the cardiac model applets allow the study of reentrant tachyarrhythmias using premature stimuli and conduction blocks to induce or to terminate reentrant waves of electrical activation in one and two dimensions. The role of some physiological parameters in the transition from tachycardia to fibrillation also can be analyzed by varying the maximum conductances of ion channels associated with a given model in real time during the simulations. These applets are available for download at http://arrhythmia.hofstra.edu or its mirror site http://stardec.ascc.neu.edu/~fenton.
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http://dx.doi.org/10.1016/s0303-2647(01)00177-0 | DOI Listing |
Sensors (Basel)
January 2025
Faculty of Architecture and Civil Engineering, Karlsruhe University of Applied Sciences, 76133 Karlsruhe, Germany.
Engineers, geomorphologists, and ecologists acknowledge the need for temporally and spatially resolved measurements of sediment clogging (also known as colmation) in permeable gravel-bed rivers due to its adverse impacts on water and habitat quality. In this paper, we present a novel method for non-destructive, real-time measurements of pore-scale sediment deposition and monitoring of clogging by using wire-mesh sensors (WMSs) embedded in spheres, forming a smart gravel bed (GravelSens). The measuring principle is based on one-by-one voltage excitation of transmitter electrodes, followed by simultaneous measurements of the resulting current by receiver electrodes at each crossing measuring pores.
View Article and Find Full Text PDFStem Cell Res Ther
January 2025
Department of Cell Biology and Histology, University of the Basque Country UPV/EHU, Leioa, Bizkaia, 48940, Spain.
Background And Aim: Human dental pulp stem cells (hDPSCs) constitute a promising alternative for central nervous system (CNS) cell therapy. Unlike other human stem cells, hDPSCs can be differentiated, without genetic modification, to neural cells that secrete neuroprotective factors. However, a better understanding of their real capacity to give rise to functional neurons and integrate into synaptic networks is still needed.
View Article and Find Full Text PDFJ Hazard Mater
December 2024
College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, China; Key Laboratory of Plant Nutrition and the Agro-environment in Northwest China, Ministry of Agriculture, Yangling 712100, China. Electronic address:
The interactions between microplastic-derived dissolved organic matter (MPs-DOM) and heavy metals (Cu, Pb, and Cd) regulate the complex environmental transport behavior of pollutants in terrestrial and aquatic environments. In this study, fluorescence excited emission matrix spectroscopy combined with parallel factor analysis (EEM-PARAFAC) and electrospray ionization coupled Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) were employed to investigate the complexation mechanism of MPs-DOM with heavy metals, as well as the effects of different environmental occurrences of MPs-DOM on the transport behaviors of heavy metals in saturated porous medium. The findings demonstrated that MPs-DOM, particularly humic-like substances containing aromatic structures and various oxygen functional groups, could form stable complexes with heavy metals.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Physics Department, Khalifa University, Abu-Dhabi, United Arab Emirates.
The spectrum of carbon monoxide is important for astrophysical media, such as planetary atmospheres, interstellar space, exoplanetary and stellar atmospheres; it also important in plasma physics, laser physics and combustion. Interpreting its spectral signature requires a deep and thorough understanding of its absorption and emission properties. A new accurate spectroscopic model for the ground and electronically-excited states of the CO molecule computed at the aug-cc-pV5Z CASSCF/MRCI+Q level is reported.
View Article and Find Full Text PDFSoft Matter
January 2025
Center for Soft Condensed Matter Physics and Interdisciplinary Research & School of Physical Science and Technology, Soochow University, Suzhou 215006, P. R. China.
Traveling waves are universal in excitable systems; yet, the microscopic dynamics of wave propagation is inaccessible in conventional excitable systems. Here, we show that active colloids of Quincke rollers driven by a periodic electric field can form condensed excitable phases. Distinct from existing excitable media, condensed excitable colloids can be tuned reversibly between active liquids and active crystals in which two distinct waves can be excited, respectively.
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