We have contrasted spectroscopic images of blood vessels under a true skin surface of mouse with laser confocal scanning microscope 3D images of them, and analyzed these optical reflection densities of vessels. We have demonstrated that the difference between the optical reflection density of high absorption isosbestic spectrum and that of low depend on the depth of a vessel linearly. We have experimentally verified the possibility of spectroscopic vessel imaging encoding depth information.

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Detailed analysis of oxygen consumption within the myocardial microcirculation is of importance to understand conditions under ischemic heart disease. However, there are currently difficulties in microscopically precise measurements of local oxygen consumptions in myocardial tissue. In this paper, a simulation model of myocardial microcirculation is proposed for analysis of local distribution of oxygen consumption. The proposed model is composed by integrating a theoretical spatially-distributed model of myocardial tissue and a detailed lumped-parameter model of normal cardiac myocyte. The proposed model was validated for an animal research in reproduction of a linear correlation between myocardial oxygen consumption and myocardial contractility. A simulation result of the model shows that local oxygen consumptions under low myocardial blood flow are spatially partitioned into an arteriolar-side normal area and a venular-side low area. Myocytes in the venular-side area lose normal activity under extremely low oxygen concentration. This result indicates the possibility that cardiac tissue is locally damaged under extreme hypoxia in the venular-side area even in case of a slight reduction of mean oxygen consumption of the myocadial tissue caused by decreased myocardial blood flow.

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In order to develop wearable motion support equipment for the elbow, the three-dimensional motion of the elbow joint needs to be measured. This paper proposes a method for measuring the elbow motion using parallel links. The proposed method is noninvasive and simple and employs linear encoders. This method enables measurement of the position and posture of the forearm, including the valgus angle, in real time. This method was used to conduct measurement experiments of the elbow motion, and the obtained results were compared with previous results obtained by X-ray radiography and anatomy. The validity of the proposed method was confirmed.

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A novel apparatus for noninvasive measurement of pressure-cross-sectional area relationship, i. e., tube law, of brachial artery was developed. It is based on an oscillometric method in which a cuff is wrapped around the upper arm and pressurized to measure the oscillation in the cuff pressure. The oscillation of the cuff pressure is caused by the volume change in the brachial artery due to heartbeats. The volume change was obtained by multiplying the amplitude of the cuff pressure with cuff compliance that had been measured from the increase in the cuff pressure just after loading a precise amount of air into the cuff. Oscillation of the cuff pressure disappears when the artery is collapsed. By using this principle, an occluding pressure OP when the artery begins to collapse was measured. A modified transmural pressure _mP_t was introduced whose origin was taken at the point where the external pressure of the artery, i. e., the cuff pressure equals to OP. Relationship between _mP_t and cross-sectional area of the artery A was obtained as the tube law:The volumetric change of the brachial artery was obtained at each _mP_t and was fitted to the function $\displaystyle A=A_b \left\{ \frac{1}{b} \ln \left( \frac{ {}_mP_t - P_b } {a} +1 \right) +1 \right\}$ where A_b, P_b, a, and b are constants while assuming constant pulse pressure. Volume elastic modulus V_E and in vivo cross-sectional area eA of the brachial artery were obtained from the tube law. Estimated tube law was very similar to that obtained by measuring the diameter of the brachial artery with ultrasound while changing the transmural pressure by pressurizing and depressurizing an airtight chamber that had been attached around the upper arm. Estimated eA correlated well with eA measured by ultrasound (R²=0.930, P<0.001, n=20) with maximum error of 9.1%. Difference in V_E obtained in the two methods was less than±3% (n=5). The present method is capable of obtaining pressure-cross sectional relationship of the brachial artery correctly with a simple process comparable to blood pressure measurement. Since it has been reported that in vivo brachial artery diameter correlates well with the severity of atherosclerosis, eA obtained in the present method might become a promising index for atherosclerosis.

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Recently, the freak accidents in home have been increased and they are caused by the asphyxiation, drowning, falling, fire, and toxicosis. Especially in bathroom, the accident frequently arise and thus the healthcare monitoring and the accident detection system can be useful for attainment of safe and untroubled daily life. While some monitoring systems for moving state using infrared ray and ultrasonic wave were already developed, these methods distinguish only whether or not a bather is moving. Also, detailed motion analysis using CCD camera has the problem of privacy for the practical use. From these viewpoints, we designed the monitoring system for the electrocardiogram and respiration signal using bathtub-installed electrodes, showing its usefulness for the healthcare and the drowning alarm during taking a bath. However, the range over which this method is possible is limited in the bathtub and thus the detection in washing place are impossible. To solve this drawback, we developed a new system capable of detecting the accident in the washing place together with the pulse and respiration rate using a bath mat type multipoint pressure sensor located in washing place of bathroom. From the results of the accuracy evaluation in 20 healthy subjects, it is demonstrated that the present system can accurately detect the accident [60/60, 100%]and show the good correlation between the pulse [r=0.99] and respiration [r=0.95]obtained from the system and those obtained from the conventional methods using the sensors attached to the body surface.

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