The aim of this paper was to synthesize and characterize microbial chitosan thin films for potential piezoelectric application. Microbial derived from the Aspergillus oryzae fungus via extraction deacetylation. Chitosan film characterized its surface morphology, chemical properties, tensile strength, topography. For application as a material, characteristics were presented in terms electromecha...

Computational modeling has traditionally played an important role in dissecting the mechanisms for cardiac dysfunction. Ventricular electromechanical models, likely the most sophisticated virtual organs to date, integrate detailed information across the spatial scales of cardiac electrophysiology and mechanics and are capable of capturing the emergent behavior and the interaction between electr...

Due to the large strain capability, electroactive polymers (EAPs) are promising materials for several engineering applications, for example: they can be used as actuators and sensors in cameras, pumps, valves, etc. Generally speaking, the mode of action in EAPs is based on Coulomb forces generated by electric field that causes the polymer membrane to contract in the thickness direction. In this...

The article entitled Effect of transcatheter aortic valve replacement on P-wave duration, P-wave dispersion and left atrial size by Dursun, et al. has contributed to our knowledge regarding the positive effects of transcatheter aortic valve replacement (TAVR) procedure on atrial electrical remodeling. In this study, TAVR procedure led to a decrease on P-wave duration and P-wave dispersion.  As...

In single muscle fibers from the giant barnacle, a small decrease in muscle length decreases both the calcium activation and the peak isometric tension produced by a constant current stimulus. The effect is most pronounced if the length change immediately precedes the stimulation. In some cases, the decrease in tension with shortening can be accounted for almost entirely by a decrease in calciu...

The coupling between cardiac mechanics and electric signaling is addressed in a nonstandard framework in which the electrical potential dictates the active strain (not stress) of the muscle. The physiological and mathematical motivations leading us to this choice are illustrated. The propagation of the electric signal is assumed to be governed by the FitzHugh–Nagumo equations, rewritten in mate...

The ability of certain materials to convert electrical stimuli into mechanical deformation, and vice versa, is a prized property. Not surprisingly, applications of such so-called piezoelectric materials are broad—ranging from energy harvesting to self-powered sensors. In this perspective, written in the form of question-answers, we highlight a relatively understudied electromechanical coupling ...

Anterior leaflet (AL) stiffening during isovolumic contraction (IVC) may aid mitral valve closure. We tested the hypothesis that AL stiffening requires atrial depolarization. Ten sheep had radioopaque-marker arrays implanted in the left ventricle, mitral annulus, AL, and papillary muscle tips. Four-dimensional marker coordinates (x, y, z, and t) were obtained from biplane videofluoroscopy at ba...

The flexoelectric effect is a coupling of polarization and strain gradient, which exists in a wide variety of materials and may lead to strong size-dependent properties at the nanoscale. Based on an extension to the classical beam model, this paper investigates the electromechanical coupling response of piezoelectric nanobeams with different electrical boundary conditions including the effect o...

A simple approach is presented for using bond-stretching and bond-bending modes to describe the static deformations of carbon nanotubes and related actuation effects. This approach allows us to analyze various phenomena in a unified way and to clarify their relationships. We discuss gap energy modulation by external strains, dimensional and torsional deformations caused by charge injection, and...