In order to study the cardiovascular hemodynamic characteristics and evaluate the artificial heart, especially the compression cardiac assist devices, we put forward a simulating device which is made of pump, valve, tubes and controller, and can be used to imitate cardiovascular system. Moreover, in this essay, we put forth an algorithm to draw pressure-volume loop with the parameters measured, including liquid pressure, volume and air pressure. The changes in the frequency and duty of control signal and in the angle of proportional valve can symbolize cardiovascular system in different heart rates, with different systole period, and at different level, respectively. The result of simulating device experiment proved to be coincident with physiology.
Cardiovascular Physiological Phenomena ; Computer Simulation ; Equipment Design ; Heart, Artificial ; Heart-Assist Devices ; Hemodynamics ; Models, Cardiovascular

Artificial heart is an effective device in solving insufficient native heart supply for heart transplant, and the research and application of novel actuators play an important role in the development of artificial heart. In this paper, artificial muscle is introduced as the actuators of direct cardiac compression assist, and some of its parameters are compared with those of native heart muscle. The open problems are also discussed.
Artificial Organs ; Assisted Circulation ; instrumentation ; Biocompatible Materials ; Equipment Design ; Heart-Assist Devices ; Humans ; Muscles

Animals ; Antlers ; Exosomes ; Mesenchymal Stem Cells ; Osteoarthritis/therapy*

Progressive functional deterioration in the cochlea is associated with age-related hearing loss (ARHL). However, the cellular and molecular basis underlying cochlear aging remains largely unknown. Here, we established a dynamic single-cell transcriptomic landscape of mouse cochlear aging, in which we characterized aging-associated transcriptomic changes in 27 different cochlear cell types across five different time points. Overall, our analysis pinpoints loss of proteostasis and elevated apoptosis as the hallmark features of cochlear aging, highlights unexpected age-related transcriptional fluctuations in intermediate cells localized in the stria vascularis (SV) and demonstrates that upregulation of endoplasmic reticulum (ER) chaperon protein HSP90AA1 mitigates ER stress-induced damages associated with aging. Our work suggests that targeting unfolded protein response pathways may help alleviate aging-related SV atrophy and hence delay the progression of ARHL.
Mice ; Animals ; Transcriptome ; Aging/metabolism* ; Cochlea ; Stria Vascularis ; Presbycusis