Physiological systems generate complex fluctuations in their output signals that reflect the underlying dynamics. The base-scale entropy method was proposed as a complexity measure to investigate the complexity of time series. The advantages of this method are simplicity and extremely fast calculation for very short data sets. This method enables analyzing very short, nonstationary, and noisy data sets. We employed this method for short-term physiological time series for analysis of heart-rate variability signals. The results show that the simple and easily calculated measure can effectively detect the complexity dissimilarity of physiological time series in different physiological or pathological states, which is convenient for clinical applications.
We apply the visibility graph analysis to human heartbeat dynamics by constructing the complex networks of heartbeat interval time series and investigating the statistical properties of the network before and during chi and yoga meditation. The experiment results show that visibility graph analysis can reveal the dynamical changes caused by meditation training manifested as regular heartbeat, which is closely related to the adjustment of autonomous neural system, and visibility graph analysis is effective to evaluate the effect of meditation.
This paper proposes that a multiscale multifractality (MSMF) method be adopted for the spatiotemporal analysis of 12-lead ECG. By using this method, the authors find that, in some frequency range, 12-lead ECG has a more complex fractal structure, and the position of the largest singularity strength range delta alpha is not relying on the data length but on the scale factor. By determining the inflexion, the MSMF proves to be more sensitive in displaying the trend that the singularity strength range delta alpha of human ECG decreases with human aging.
In this study we evaluated the effect of quercetin on D-galactose-induced aged mice using the Morris water maze (MWM) test. Based on the free radical theory of aging, experiments were performed to study the possible biochemical mechanisms of glutathione (GSH) level and hydroxyl radical (OH-) in the hippocampus and cerebral cortex and the brain tissue enzyme activity of the mice. The results indicated that quercetin can enhance the exploratory behavior, spatial learning and memory of the mice. The effects relate with enhancing the brain functions and inhibiting oxidative stress by quercetin, and relate with increasing the GSH level and decreasing the OH- content. These findings suggest that quercetin can work as a possible natural anti-aging pharmaceutical product.
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