Liquid storage of spermatozoa is important for artificial insemination and herd genetic breeding. However, the extended time of storage inducing the rapid decline in spermatozoa quality limits the development of this technology. The molecular mechanisms underlying liquid storage of spermatozoa remain largely unexplored. In this study, the effects of liquid storage on functional quality of spermatozoa were assessed in goat (Capra hircus). The time-dependent decline in spermatozoa motility showed a strong correlation with the significant increase in apoptosis. Moreover, apoptosis-related ultrastructural changes were observed, especially the defects in mitochondria. A significant decrease in mitochondrial membrane potential and changes in the expression of mitochondrial apoptosis-related proteins indicated mitochondrial dysfunction and mitochondrial apoptotic pathway activation. Notably, the abnormally high level of reactive oxygen species (ROS) caused by liquid storage resulted in oxidative damage to mitochondria and accelerated mitochondria-dependent apoptosis, as demonstrated by the addition of ROS scavenger N-acetylcysteine. Furthermore, critical differentially expressed proteins involved in mitochondria-dependent apoptosis and antioxidant defense were identified and profiled by quantitative proteomic analysis, facilitating the understanding of molecular regulation of ROS-induced mitochondria-dependent apoptosis. These outcomes provide insights into the mechanisms underlying liquid storage of goat spermatozoa and enhance the progress of semen storage technology.

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The fluid dynamics of a natural aortic valve are complicated due to the highly pulsatile flow conditions, the compliant wall boundaries, and the sophisticated geometry of the aortic root. In the present study, a pulsatile flow simulator was constructed and utilized to investigate the turbulent characteristics and structural deformation of an intact silicone aortic root model under different flow inputs. Particle image velocimetry and high-frequency pressure sensors were combined to gather the pulsatile flow field information. The results demonstrated the distributions and the variations of the jet flow structures at different phases of a cardiac cycle. High turbulence kinetic energy was observed after the peak systole phase when the flow started to decelerate. Deformations of the aortic root upstream and downstream of the valve leaflets under normal boundary conditions were summarized and found to be comparable to results from clinical studies. The cardiac output plays an important role in determining the strength of hemodynamic and structural responses. A reduction in cardiac outputs resulted in a lower post-systole turbulence, smaller circumferential deformation, a smaller geometric orifice area, and a shortened valve-opening period.

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Pulsatile flow over open cavity represents one type of physiological phenomenon related to a few common cardiovascular diseases, such as cerebral sidewall aneurysm and arrhythmia-induced thromboembolism in the left atrium appendage (LAA). In recent years, endovascular treatments using mesh-based implants have become increasingly popular. In this paper, we study the characteristics of pulsatile flow over a simplified sidewall cavity under two Reynolds/Womersley number conditions using Particle Image Velocimetry. The impacts of a regular mesh and a superhydrobobically-coated mesh on the cavity flow are investigated. Our results quantify the phase-to-phase changes of the flow fields and reveal the formation and the transport of the primary vortex over the ostium of the rectangular cavity. Results suggest the meshes diverted the main flow away from the cavity and prohibited the development of the primary vortex. A penetrated jet flow was formed near the front side of the cavity due to the presence of the mesh. The superhydrophobic mesh dramatically reduced the kinetic energy of the penetrated jet into the cavity. It indicates the mesh flow diversion is effective because of the destruction of the shear-induced vortex dynamics that causes flow stagnation on the rear cavity wall. Our results also indicate the superhydrophobic coating is potentially beneficial in terms of reducing the hemodynamic loading inside the cavity.