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Heat conduction in biological species depends on their structural composition, characterizing heat conduction property offers important information about the physiological function in vital organs. We propose a heat flux measurement technique based in the photothermal beam deflection to detect changes in thermal properties of biological tissue. The heat flux sensor has a sensitivity of 46.65[μW/(mW/cm2)]. We present some preliminary results for measurements of heat conduction in chicken tissue. [ABSTRACT FROM AUTHOR]

Most studies of blood pressure control consider only the relationship between blood pressure and heart rate. The aim of this work was to study the contribution of blood volume to the stability of blood pressure. Time series analysis was applied to three variables: systolic blood pressure (SBP), inter beat interval (IBI) and pulse volume (PV), in 10 healthy subjects who underwent an orthostatic challenge. During orthostatism, IBI was shortened due to decrease in vagal activity and increase in sympathetic activity to the heart. The mean SBP increased, with a trend of higher sympathetic activity to the blood vessels. However, mean PV decreased without change in the PV variability. Negative linear correlations between SBP and PV were observed in most cases. Moreover, the linear model explained better the variability of SBP in relation to PV than the relation between SBP and IBI. [ABSTRACT FROM AUTHOR]