The author in this report describes the present condition and anticipated future trends related to the measurement of air pollution in Japan. Air pollutants, such as SO₂, NO_x, CO, O_x, HC and particles, were mainly measured by local self-governing bodies and national air pollution measuring stations. The methods used in measuring these air pollutants at the sources and in environments were those provided for in the Japanese Industrial Standards (JIS) or in the Air Pollution Control Law. However, as the standardization of environmental air pollution measuring methods and of reference materials is delayed, the establishment of JIS in this area is strongly desired.

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At present, metal electrodes are employed as biomedical sensing electrodes, but these pose many problems, such as noise voltages and polarization potentials. An insulator also can be used as an electrode so that biomedical signals can be sensed by its capacitive coupling with the skin. In this paper, barium-titanate ceramics are used for insulator materials, because the electrodes can be made thick and mechanically strong by virtue of their large dielectric constant. The noise voltage characteristics of this barium-titanate ceramics electrode were examined specifically and it was found that this electrode was noise-free from the beginning of installation. This result stems from the fact that this capacitive type electrode does not employ the conduction mechanism caused arising from the electrochemical reaction, the instability of which is the noise source of the metal electrode. These capacitive electrodes are applied to EEG and ECG as electrodes. To decrease electrical artifacts, this electrode has been made active type that has FET impedance converter incorporated directly within the electrode. The ECG electrode does not require an electrolytic paste because of its high-input impedance.Pasteless operation is suitable for long term application such as patient monitoring in an intensive care unit. When this electrode is mechanically stressed, artifact voltage is generated. This artifact voltage is due to the piezoelectric effect of the barium-titanate ceramics. For this reason, the large mechanical stress such as tapping the electrode with finger should be avoided in the use of this electrode. However, it will be possible to decrease this voltage, if the dielectric material that has no piezoelectric effect is used. Moreover, this barium-titanate ceramics electrode protects the patient from electrical shock caused by dc current.

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In order to obtain precise measurements and analysis of the splenic circulation in which both slow and fast phase coexist, we applied two kinds of analytic methods. For the slow phase, three compartments analysis was adopted using a radiosplenogram and a blood dilution curve with a tracer injected into antecubital vein. For the fast phase analysis the tracer was injected into the celiac artery and the radiosplenogram was subjected to simulation analysis with an analog computer. In the latter procedure the transfer function of heart-lung system to spleen dynamics was computed and applied to the precise evaluation of recirculation component.
The first circulation component was determined by subtracting the recirculation component from the original RSG. Thus the transfer function of the spleen in the fast phase was reduced.
With results of two analysis in each phase, a whole model of splenic circulation was constructed with distribution ratios to flow in and with rate constants to flow out of three compartments which were supposed to exist in the spleen. Aiming at clarifying the dynamics relationship among heart-lung, spleen and sykemic circulation, several simulation experiments were carried out with this model. These results were useful in applying this method to practice.

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Recently some papers have been published on Electrophrenic Respirators (EPR). Glenn et al. described clinical uses of EPR for the patients with hypoventilation of central origin. For the same purpose, we have developed a new EPR which stimulates the phrenic nerve synchronized with its proper impulses.
The characteristics of this EPR are as follows. Common mode noises such as ECG, EMG and 50 Hz are suppressed using a low noise differential amplifier with a high discrimination factor and a bandpass filter. Differential mode noises from electrodes and so on are also removed by logic circuits, which are designed on the characteristics of the proper impulses from the phrenic nerve. By this method, the nerve impulses can be picked up without injuring the phrenic nerve. An amplitude modulated pulse train is used for nerve stimulation in order to obtain natural breathing.
The experiments were performed on the dog, and the following results were obtained. The leading electrodes were attached to the C₅ fibres on one side and the stimulating electrode was attached to the main trunk of the phrenic nerve on either the same or the opposite side. Then, transverse myelotomy between Th 1 and Th 2 and the blocking of C₆, C₇ fibres of the phrenic nerve were performed. After this operation, the movement of thorax stopped and that of abdominal wall decreased, so that the depth of respiration decreased and the rate of respiration and the CO₂ partial pressure of blood increased. These respiratory patterns were considered analogous to that of central hypoventilation. After applying this EPR, such symptoms of hypoventilation clearly improved. Through these acute experiments, it was shown that this EPR can operate synchronously with the phrenic nerve impulses, and it has the possibility of curing central hypoventilation without disturbances of the respiratory feed back loops.

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An analytical method is presented here for analyzing the blood flow in arteries. The main features of the change in the shape of the pressure wave in the arteries as it travels from the heart to the periphery are that (1) the wave front of the pulse becomes steeper; and (2) the peak value of the pressure pulse increases. The former behavior can be interpreted as a general aspect of a nonlinear wave. The latter behavior can be explained by the effects of variations in elasticity of the tube with distance along its axis. The pulse wave propagating into a quiescent region. of blood in an artery can be regarded as a solitary simple wave. In the case of the flow in a tube with constant cross-sectional area and constant elasticity with distance along its axis, this simple wave approximation enables us to obtain the well-known Riemann's solution for a travelling simple wave. It is known that discontinuities must ultimately be formed in every nonlinear wave which shows steepening phenomena. By using Riemann's solution, we can estimate the time and place of formation of the discontinuity in the tube, and show its possible. occurrence within the anatomical distances. In the case of the flow in a tube with varying, cross-sectional area and varying elasticity with distance along its axis, we find the approximate. Riemann invariants on the characteristics, which give us very simple relations among the : pressure, the fluid velocity, and the wave speed with the aid of the simple wave approximation. Using these relations, we can calculate quite easily the change of the shape of a pulse wave. travelling in an artery. For the clinical applications, we show the possibility of regarding the, velocity of the peak of the pressure pulse as an indicator of the performance of the heart.

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The relations of the left ventricular volumes of the intact canine hearts, such as stroke volume (SV), end-diastolic volume (EDV) and end-systolic volume (ESV), to the heart rates were studied. After the atrio-ventricular node was blocked by injecting a small amount of formalin, ventricular pacing was induced. Varying the pacing rates, the left ventricular volumes were measured by means of thermal dilution using a thermistor with a very short time constant. The results showed that under left atrial pressure clamp, increases in pacing rates ranging from 50 to 160 beats/min caused decreases in EDV to considerable extents but no consistent and large changes in ESV. Measurements of the left ventricular end-diastolic pressure (LVEDP) under left atrial pressure clamp demonstrated that reductions in EDV at higher pacing rates were caused by lowering of LVEDP. From these results, some mathematical expressions on the control of SV are presented.

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As a part of automated multiphasic health testing, the new centralized, automated system for mass ECG screening, developed at the Center for Health Care of Aichi, is capable of processing 200 Frank lead exercise ECGs daily.
Twelve-lead ECGs could also be chosen in this system because of their widespread acceptance, consensus of opinion on diagnostic criteria, availability and familiarity to most clinicians.
System facilities are composed of a CPU (JEC-6 digital computer) with a 4-channel A-D converter, 3 accessory memory units and functional interfaces (originally designed) which control the lines between the CPU and terminal devices.
ECG operations such as recording of INST, calibration signal and chart driving etc. are controlled completely automatically by the CPU through the central control box, while the optimal level and range of the feeding signals can be monitored on the chart or oscilloscope. Frank lead X, Y, Z ECGs are fed into the CPU before and after double Master's two-step test if no significant abnormality was noted in the pre-exercise recording. Stored computer program can recognize the peak or nadir of the ECG waves, and determine the amplitude and duration of the P, QRS, and T waves. Input ECG data are also recorded on the chart and FM data recorder after a starting signal, BCD identification number, and signal indicating whether there is a pre-exercise or a post-exercise ECG. Finally, the ECG diagnoses are identified by the decision tree logics, and the results are made available in a printed form and a punched paper tape. The total processing time of a pre-exercise ECG is within 35 seconds and that of a postexercise ECG is less than 25 seconds.
Due to high-speed processing capability with satisfactory accuracy, reproducibility and economy, this system could be efficiently applied to mass screening of cardiovascular diseases.

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