Influence of Cold Sensation on Plantar Tactile Sensation for Young Females

Cold sensation (CS) is a cold feeling on people’s hands or feet; this is a well-known health problem for young females. Plantar tactile sensation plays an important role in postural control and is affected by skin temperature. However, there is no research focusing on the relation between CS and plantar tactile sensation. In this study, we address the question of whether the CS influences plantar tactile sensation. 32 non cold sensation (Non-CS) and 31 cold sensation (CS) young females have participated in this research. A tactile sensation test was conducted at five plantar points (first and fifth toes, first and fifth metatarsal heads, and heel). Experimental results showed that although there was no significant difference at the first and fifth toes as well as the first metatarsal head and heel, the sensation threshold at the fifth metatarsal head for CS was lower than the Non-CS (21.61 ± 8.10 μm, 27.42 ± 11.02 μm respectively, p < 0.05).  It was concluded that plantar tactile sensation for young females with cold sensation was more sensitive compared to healthy subjects

Reentrant excitation in an analog-digital hybrid circuit model of cardiac tissue

We propose an analog-digital hybrid circuit model of one-dimensional cardiac tissue with hardware implementation that allows us to perform real-time simulations of spatially conducting cardiac action potentials. Each active nodal compartment of the tissue model is designed using analog circuits and a dsPIC microcontroller, by which the time-dependent and time-independent nonlinear current-voltage relationships of six types of ion channel currents employed in the Luo-Rudy phase I (LR-I) model for a single mammalian cardiac ventricular cell can be reproduced quantitatively. Here, we perform real-time simulations of reentrant excitation conduction in a ring-shaped tissue model that includes eighty nodal compartments. In particular, we show that the hybrid tissue model can exhibit real-time dynamics for initiation of reentries induced by uni-directional block, as well as those for phase resetting that leads to annihilation of the reentry in response to impulsive current stimulations at appropriate nodes and timings. The dynamics of the hybrid model are comparable to those of a spatially distributed tissue model with LR-I compartments. Thus, it is conceivable that the hybrid model might be a useful tool for large scale simulations of cardiac tissue dynamics, as an alternative to numerical simulations, leading toward further understanding of the reentrant mechanisms

Estimating Sleep Stages Using a Head Acceleration Sensor

Sleep disruption from causes, such as changes in lifestyle, stress from aging, family issues, or life pressures are a growing phenomenon that can lead to serious health problems. As such, sleep disorders need to be identified and addressed early on. In recent years, studies have investigated sleep patterns through body movement information collected by wristwatch-type devices or cameras. However, these methods capture only the individual’s awake and sleep states and lack sufficient information to identify specific sleep stages. The aim of this study was to use a 3-axis accelerometer attached to an individual’s head to capture information that can identify three specific sleep stages: rapid eye movement (REM) sleep, light sleep, and deep sleep. These stages are measured by heart rate features captured by a ballistocardiogram and body movement. The sleep experiment was conducted for two nights among eight healthy adult men. According to the leave-one-out cross-validation results, the F-scores were: awake 76.6%, REM sleep 52.7%, light sleep 78.2%, and deep sleep 67.8%. The accuracy was 74.6% for the four estimates. This proposed measurement system was able to estimate the sleep stages with high accuracy simply by using the acceleration in the individual’s head

On a portable memory device for physical activities and informations of maternal perception

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