Periodic fluctuation or intermittency of blood cell velocity in the capillary bed has been observed by many investigators in the resting skeletal muscle, mesentery and other tissues. The Purpose of this study is to elucidate the effect of such intermittent capillary flow on O₂ transport in the skeletal muscle by dynamic computer simulation.
In this simulation, capillary channels are assumed to be uniformly distributed in parallel along the muscle fiber. Intermittent capillary flow is simulated by revolving the open capillary in every group of four adjacently located capillaries, so that in each of 4 phases of the same duration, the tissue is supplied with oxygen by the different capillary corresponding to the phase respectively.From this model we could formulate partial differential equations on both O₂ transport by the capillary blood flow and O₂ diffusion into the tissue with simple boundary conditions, and numerically solve them by digital computer under various conditions of intercapillary distance, O₂ consumption, etc.
By comparing the tissue pO₂ distributions under intermittent flow with those under steady flow, it has been revealed that the tissue pO₂ at the venous end of the intermittent model, particularly at the tissue located farthest from the open capillary, was higher than that of the steady one. This smoothing effect of tissue pO₂ by intermittent capillary flow was increased by increasing O₂ consumption and/or by decreasing capillary density in the tissue. From these results it was concluded that the intermittent flow is an effective means of supplying O₂ to the tissue with smaller flow rate at rest, because it keeps the tissue pO₂ distribution uniform around the venous end by raising the pO₂ value at the most poorly supplied corner under steady flow.

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A new method of Braille display has been proposed for the blind. The device automatically displays 2-dimensional image as a pattern composed of raised dots so as to be recognizable by the tactile sense of a fingertip.
Each raised dot is obtained by elevating a contact pin (0.7mmφ) placed on a tiny bimetal (0.1mm×2mm×15mm) which is heated with a micro-heater. The micro-heater is made of Ni-Cr thin-film (1500Å) which is formed on a glass plate by sputtering. Displacement and time response of the raised dod is estimated on the basis of electrical analogy of thermal circuit and measured by using a solid-state camera. From the estimation and the measured values, it has been found that the relationship between the input voltage V (s) and output displacement X (s) could be presented by the transfer function as
X (s) =α1/s+1/τV (s)
(α=0.125, τ=5sec),
though coefficient a was reduced when a fingertip was placed on a contact pin of the device.
In order to examine the ability and characteristics of tactile pattern recognition by our device, tactile recognition rate of 7 Braille patterns was compared with that of our raised dot patterns corresponding to the Braille ones. Experimental result showed that the tactile recognition by our method had characteristics similar to that of Braille ones.

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Two algorithms for identifying bacteria are investigated. One is the distance analysis with pattern slide method, and the other is the power-spectrum analysis of the differential pattern of the growth curve. Bacterial growth is measured by monitoring the turbidity change of culture medium. An automated system of measuring and data processing is constructed for the identification of bacteria by microcomputer, turbidity detecting apparatus and some electrical circuits. For ten species of coliform bacteria, 93.3% of tested 178 isolates and 95.0% of tested 190 isolates have been correctly identified by the distance analysis and the power spectrum analysis, respectively. It is contended that multi-channelization of the system is essential as it leads to rapid and reliable identification of bacteria.

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The new method of controlling respiratory system to maintain constant alveolar CO₂ concentration is proposed. The controlled system is regarded as a two-input single-output system whose inputs are metabolic rate and air ventilation rate while the output is alveolar CO₂ concentration. The metabolic rate which cannot be easily observed is theoretically reproduced by using nonlinear inverse of the given controlled system. The contribution of metabolic rate change to the output value of alveolar CO₂ concentration is theoretically calculated and it can be compensated from the other explicit input terminal whose value can be easily set, by using the input function of air ventilation rate obtained from the nonlinear dynamic compensator.

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For the prevention of pneumoniosis, it is very important to detect the total amount of dust retained in the human lungs as early as possible. Up to the present time, however, no effective method for accurately measuring dust in the lungs has been developed. Proposed here is a new method of measuring the total amount of dust in the lungs using the magnetic property of the dust. We have made an equipment to measure the remnant fields of the dust in the lungs, which are produced by exposing the thorax to an external magnetizing field just prior to the measurement.
This equipment consists of a fluxgate magnetoscope with a differential probe, an electrical magnet to magnetize subjects, a detection system and a scanning bed made of non-magnetic materials.
We measured the magnetic field of the thorax of 55 persons who worked in a manufacturing factory and evaluated the total amount of dust accumulated in their lungs. We then compared the total amount of dust detected with the chest X-ray index, and found some positive correlations.

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[in Japanese]

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