The great number of papers for bio-weak-signal measurement and signal processing has already pub-lished in all over the world. Recently, because of the remarkable progress in measuring sistrument and computer technology, the electric phenomena of human body is accurately clarified.On the other hand, nonlinearity of biosignals is missed a limit for analysis or interpretation of biosignals. This special issue is aimed to have a new understanding of essence of biomesurements and to secure reliability of signal processing.

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[in Japanese]

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The periodgram analysis of sunspot data and interpretation of spontaneous firings measured from cat's mesen-cephalic reticular neurons by the Ornstein-Uhlenbeck model are introduced as practical examples of linear and non-linear analyses of interpretation of signals, respectively. It may be useful to refer to the author's previous paper⁽⁵⁾.

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Electroencephalography (EEG) is a noninvasive, nonrestrictive and low-cost means of estimating brain activities with time resolution less than millisecond. Moreover, because of the remarkable progress in computer technology, it is possible to take the conductivity inhomogeneity into account in computing potential distributions, and hence the characteristic of being sensitive to low-conductive tissues such as skull is no longer a serious drawback of EEG In this paper, after a short description of the generation mechanisms of EEC., major methods for solving the inverse problem are introduced. The inverse analysis is based on the forward solutions, namely we need a means to calculate potential distribution on the scalp surface generated by EMF sources in the brain. Here, the construction process of a multi-shell head model is described, and an efficient forward technique suitable for such a head model is introduced.

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To investigate the characteristics of the electrolytically chloridized silver-silver chloride electrode used in the field of electronic biomedical instrumentation, the electrode potential in the range of weeks and the impedance of 10mHz to 10kHz were measured in 0.1M and 1M KCI solutions at 25.0°C. The amounts of chloridized electric charge were controlled within 0.1mC/cm2_??_5C/cm². The potentials (vs. Ag-AgCI) of silver-silver chloride electrodes in 0.1M KCI solution were shown. The potentials were becoming stable after about 2 weeks of chloridizing process and around 10 to 20μV in the vicinity of zero-potential . The minimum points appear in the curves of impedance versus chloridized electric charge at about 0.5C/cm² in 0.1M and 1M KCI solutions. It shows the most suitable condition of the process for biomedical instrumentation interfaces. However, the amounts of 1 to 3C/cm² should be practically chosen because of the loss of AgCl while working. The suitable amount of chloridized electric charge Q should be selected as follows: Q=1_??_3C/cm² in measurements in dc or the lower frequency rather than 10Hz, and Q<0.1C/cm2 in the higher frequency range over 1kHz.

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Measurement of skin impedance locus at high time-resolution is needed for evaluating stress, effects of acupuncturing and so on. In this report, we proposed a new measuring method of the skin impedance lo-cus which have advantages over the previous methods. In order to check the validity of a new measuring method in actual measurements, we performed measurement of the time variation in skin impedance locus at high time-resolution using the new method. We examined how the skin impedance locus change with auditory stimulus and quantified the change in skin impedance locus. As a result, we confirmed that the measurements precision and the time-resolution of the new measuring method were enough for measuring the temporal variation in skin impedance locus. We also found that the temporal variation in skin impedance locus, that is, the detail of the temporal variation in electrical properties, can be evaluated quantitatively by some of the skin impedance parameters estimated from impedance locus.

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The final goal of this study is to develop a conductive polymer micro-electrode array as a neural interface, which is implantable into a biological system for stimulating peripheral or central nerves. Such an electrode is expected to have more affinity to a biological system than conventional metal electrodes. This time we used polypyrrole (PPy) as the conductive material. In order to develop the PPy-based electrode array, it is necessary to fabricate micro-patterns of PPy. Therefore, we proposed the micro-patterning method using photochemical reaction of oxidative polymerization agents. First, a plastic film was coated with the photochemically reactive agents. Thereafter, the agents were exposed under UV light with a patterned mask so that the PPy patterns could be fabricated on the unirradiated surface after contact with pyrrole vapor. As a result, the 3μm-width patterns could be fabricated, and the conductivities of PPy increased by means of suitable polymerization time. These results suggest that the PPy patterns seem to be applicable to the electrode array.

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A new type of multi-electrode array system for long term neural cell cultivation has been developed. The core of the system is an 8 room microchamber array, which consists of thick photoresist, SU-8, with 8-channel multi electrode array in those rooms. The biotin coated microchamber array plate is covered with the streptavidin decorated cellulose semipermeable membrane, which is fixed on the surface of the plate by streptavidin-biotin attachment, separating those rooms from the nutrient medium circulating above. The advantages of the system are; (i) contamination-free cultivation of neural cells achieved by the sealing of the semi-permeable membrane lid on the microchamber array, (ii) simple and flexible design of the microchamber array for position fixing of cells using the thick-photoresist wall with 1-5 micrometer width and 25 micrometer height, (iii) long-term simultaneous measurement of optical microscopic observation and electric recording. When nerve cells were cultured in the microchamber array, those cells have grown safely without any contamination. Those results proved a part of the potential of our multi-electrode array system.

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We have developed a novel method for on-chip cultivation of neural cells in flexible agarose-microchamber array on the glass slide. Agarose-microchamber is a micrometer order cavity constructed on the surface of agarose-layer by molding the 50-micrometer-high square/circle shaped micro-cast of thick photo-resist, SU-8. In addition, the shape of agarose-microchamber was rearranged by using the “photo-thermal etching method”, in which we used infrared (1064-nm) focused laser beam as the heat source to melt and remove a portion of agarose gel at the heating spot. By using the photo-thermal etching method we can also manufacture narrow tunnel-shaped channels between microchambers. When nerve cells were cultured on the agar-microchamber array chip, the nerve cells in two adjacent microchambers connected through the photo-thermal-etched channel after 48 hours of cultivation. Those results suggest the potential of agarose-microchamber array integrated with the photo-thermal etching method for the next stage of the single cell cultivation and measurement of nerve cells, such as real-time control of cells' interactions during cell cultivation.

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High spatial resolution mapping of cortical evoked-potentials may offer efficient and less-invasive recording of overall neu-ronal activities. because the signals involve population of neurons' activities. This paper proposes and develops the multiple-site surface microelectrode that maps cortical evoked potentials with high spatial resolution, 32 recording sites over a 2-mm-square area, and each size of the sites is 100-μm-square. With lithographic technologies, the conductive gold layer is sandwiched between an insulating polyimide layer and a polyimide substrate. Unlike conventional silicon microelectrodes, the flexible polyimide substrate can follow the convex and pulsative cortical surface, and realize less-invasive epidural recording. The impedance of each site is around 75 kΩ at 1 kHz, proved small enough to detect reliable cortical signals. Through in vivo experiments on the rat auditory cortex, the electrode achieves significant auditory-evoked potential maps, which are useful for examining cortical functions and varieties of evoked potentials.

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We employ the independent component analysis (ICA) for multiple-site grand-averaged auditory-evoked-potentials and show its feasibility to interpret the data physiologically. We first simulate near field potential at auditory cortex to examine how ensemble firing activities and synaptic activities generate the potential: both arise biphasic potential and firing activities are followed by synaptic activities by a few millisecond. We then implement ICA to our multiple-site auditory-evoked middle latency responses (MLR). The simulation and previous reports suggest that ICA successfully extract from the data three significant components, that are cortical firing activities, cortical synaptic activities, and far activities. ICA also shows how these compo-nents contribute to MLR waveforms and suggests how typical MLRs are generated: MLR only with N_a-P_a-N_b appears when both synaptic activities and firing activities are sufficiently large: the N_o-P_o-N_a-P_a-N_h complex appears when both are not so large; and the N_A-P_A-N_B-P_B-N_C complex appears when both are sufficiently small.

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During development, cortical neurons show highly synchronized spontaneous activity. This spontaneous activity probably reflects the mechanisms underlying proper network formation regulated by activity-dependent synaptic modification. To see long-term transition in this spontaneous activity, we constructed a microelectrode-array (MEA) based continuous monitoring system. Rat cortical neurons were cultured on MEAs with 64 embedded electrodes and maintained in a conventional CO₂ incubator. A perfusion system for medium changes and recording setup for electrical signals were directly connected to the MEA in the incubator. Culture medium was continuously perfused at a very slow rate (0.1 ml/h), which was quite effective to keep constant conditions without contamination. Using this system, we succeeded in recording spontaneous activity of cultured cortical networks, almost continuously from 5 days to more than one month in vitro. It was revealed that the spontaneous activity patterns showed transition from simple synchronized bursts to complex mixture of multiple patterns, separated by a brief silent period at approximately 2 weeks in vitro.

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Optical imaging based on intrinsic signals are widely used in visualizing the functional organization of the cortex. However, in general, the evoked optical changes are small compared to the background optical intensity. In this study, we proposed a method for the extraction of neuronal activity dependent signals, based on the well-known t value which is used in the evaluation of the difference between means of two samples. We have applied this method to reveal the function organization in the primary visual cortex of cats. By evaluating the statistical significance at each pixel, this method demonstrated strong ability to filter out the noises induced by such as the movement of blood vessel or cortical surface.

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This paper examines frequency characteristics of muscle, which show differences between slow and fast twitch fiber type muscle in normal and hypokalemic rats. The characteristics of muscle stimulating frequencies and EMG amplitude was studied by using control theory. The EMG was recorded from soleus (slow twitch fiber type) and extensor digitorum longus (fast twitch fiber type) in vivo. It was found that muscle showed different frequency response, and that under hypokalemia each muscle showed poor response. Furthermore, in response to electric stimulation to achieve an equivalent level of response, it was found that muscle needed higher electric intensity than nerve-muscle and muscle showed remarkable decay under hypokalemia. These results suggest that the main disease origin under hypokalemia can be ascribed to muscle condition, and that it is most efficient to stimulate nerves in order to control muscle.

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We examined the involvement of electrical interactions between myocytes in the genesis of fluctuation of spontaneous contraction rhythm in cultured cardiac myocytes. The fluctuation of contraction intervals increased when intracellular pH of myocytes decreased. Intracellular acidosis is known to reduce gap junctional conductance. In addition, treatment of myocytes with 12-doxyl stearic acid, a reversible blocker of gap junction channels, resulted in the increase of fluctuation of contraction intervals. The present findings suggest that tight electrical coupling between myocytes through gap junctions is one of the crucial factors for the stabilization of contraction rhythm in cultured cardiac myocytes.

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To clarify the mechanism of the information processing in the brain of living organisms, and investigate information coding of a neuron, a reasonable mathematical model of neuron is nedded. Various models have been proposed and analyzed for now, some relationship between bursting response and bifurcations. In this paper, we propose a simple and effective model to realize bursting phenomena in Amari-Hopfield coupled neurons. In this model, we can constructively design desirable bursting responses. Bifurcation diagrams and some analytical results are given, and a basic design scheme to generate a bursting is shown.

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A method was introduced for computing the three dimensional distributions of electro static potentials and forces in a DNA molecule with helically distributed electri cal charges. A cylindrical model of DNA molecule composed of an inner region where a discrete char ge does not exist, a middle region where there is an interaction between charges and the ex ternal region where the ions interact. The potential in each region was described by Laplace and Poisson equations. The Green function method was applied for the discrete helical charge distrib ution within a one helical turn of the finite cylinder. The calculated potentials and forces depended on the circumferential angles. The present method, when it was improved, will be available for evaluating the free energy of the DNA molecule.

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In this paper, the effect of boundary in inhomogeneous volume conductor to the properties of nerve excitation in neural magnetic stimulation with a figure-of-eight coil is analyzed with simulation. We estimated the secondary electric field produced by electric charge on the boundary between the tissues such as muscle, fat and bone with different permittivity. The electric field and the spatial derivative of the induced field (activating function) along nerve fiber in homogeneous and inhomogeneous medium were calculated. The nerve excitation properties in homogeneous and two types of inhomogeneous volume conductors were compared. The simulation indicated that the secondary electric field caused by the electric charge on the boundary have an effect on the nerve excitation property and that the analysis of such boundary effect on the nerve excitation property is important for the understanding of the mechanism of neural magnetic stimulation.

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We examined magnetoencephalography (MEG) coherence in the 5 bands (theta, alphal alpha2 betal and beta2) while the subjects were performing a working memory tasks. MEG signals were recorded using the whole-head SQUID system as 5 healthy males participated. The coherence was used to provide a functional measurement of corticocortical communication. The tasks required comparing each of the current stimulus to the one that appeared on either verbal or spatial attributes 1_??_3 trials previously. The results showed that coherence in the beta2 (19_??_30Hz) band between regions of left hemisphere dominance significantly increased with increasing memory load during verbal working memory tasks. On the other hand, significant changes of coherence with increasing memory load during spatial working memory tasks were not obtained between all regions in the beta2 band. These results suggest that the spatial and verbal working memory tasks differently modulate the component of the neural circuit, and greater connections between the cortex regions of the left hemisphere increase with verbal working memory load.

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We investigated the effect of auditory stimulation on the human motor cortex. The motor evoked potentials MEPs were recorded from the right first dorsal interosseous muscle during 5% maximal voluntary isometric contractions. Transcranial magnetic stimulation (TMS) was performed with a round coil. In the first experiment, the loud auditory stimulation was composed of 35 trains of 135 dB (SPL) pulses of 0.1 ms duration. Between the onset of each pulse was 6 ms. The interval between auditory stimulation and TMS ranged from 10-200 ms in 10 ms increments. In the second experiment, we used two tones, a high tone and a low tone between 60-100 dB. In this experiment, the effects of auditory stimulation on the motor cortex were examined at a period of 30 ms.
Loud of auditory stimulation suppressed MEP responses when it preceded the magnetic stimulation at a peak of 30 ms. While high auditory tone stimulation suppressed MEP responses at 100 dB (SPL), low auditory tone stimulation did not.
These results show that inhibitory action in the motor cortex is highest at 30 ms after loud auditory stimulation. Additionally, tone of the sound component seems to be related to the magnitude of motor cortex excitability.

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In order to measure the auditory evoked magnetic fields related to the linguistic processing by magnetoencephalography, four right-handed Japanese subjects were exposed to series of synthesized Japanese spoken words, which were presented equally to both ears. The subjects assigned the words to one of two categories such as fish/plant, etc., and immediately clicked a left or a right mouse button allocated to the category. The reaction time (RT) from the end of the noun to the click was recorded. The corresponding neuromagnetic responses from both sides of the brain were recorded simultaneously with a dual 37-channel SQUID magnetometer (BTi Inc). Recorded RTs varied among subjects, even across the sessions in each subject, so that about 300 epochs were selectively averaged in single sessions. The responses at latencies between -300 and 500 ms were sought, and their magnetic field patterns were analyzed. The equivalent current dipole of the responses at latencies between 200 and 500 ms was estimated in the inferior-medial area apart from primary auditory cortex in the left temporal lobes. These results indicate that the responses at latencies between 200 and 500 ms are related to linguistic processes.

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It is not clear how functions of the cell are affected or not affected by the static magnetic field. This paper discusses the effects of the static magnetic field on the intracellular information transmission that controls the cell movement and adhesion. The low-density fetal bovine serum was used to synchronize of the cell proliferation and then the cell morphology, the cell adhesion activity, the fluorescence of the actin-based cytoskeleton and the cell metabolic activity were experimentally observed. When the cells are exposed the static magnetic field of 10mT and 50mT, the morphology of the cell is clearly affected, and the cell adhesion is suppressed. The actin-based cytoskeleton is contracted. The cell metabolic activity, on the other hand, is enhanced by the exposure to the magnetic field. Based on those results of experiment, the mechanism, by which the static magnetic field affects the cell movement and adhesion, is discussed. A qualitative model is proposed to represent the course of information transmission.

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It is much important to examine the change of waveform in short section in EEG clinical diagnosis. The goal of our research is to construct a support system for diagnosis by detecting characteristic EEG waves and labeling them in short period. The labels used in this research are hump wave, spindle and K-complex wave. They are typical characteristic waves appeared in sleep stage II. We proposed the method using the nature that generally nonstationary waveforms are able to divide into many short stationary segments. EEG was divided into many sections by using locally stationary autoregressive model and each divided section was labeled into coresponding characteristic wave by using frequency spectrum acquired by Goertzel method. We applied this method for clinical EEG data. Evaluation of this method was performed by comparing with medical doctor's labeling of hump wave. The results for applying to two normal subjects' data showed the detection rates of hump wave are over 80%. It is also suggested that our method is effective to detect not only stationary waves but nonstationary characteristic waves such as hump wave.

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At present various approaches are being used to analyze brain function. One of these is the analysis of EEGs (electroencephalogram), by which it is becoming possible to evaluate brain activity and abnormalities in the brain from the EEG observed on the scalp. There remain many unknown aspects of the source of EEG and their mechanism of propagation. A clue to such an approach is causality analysis, whose objective is to analyze causality by quantifying correlation relations, including the directions of information flow, among measurement sites, based on multiple EEG series obtained from multiple sites on the scalp. The method should be applicable to the diagnosis of disease such as the detection of individual abnormalities and failure of information propagation. Consequently, we have proposed Multidimensional directed information analysis as a means of causality analysis in which the flow of information among all signals are investigated.
There are many multidimensional signals in nature, for which the number of information flow sources is unknown. It is very important to find out the number of the sources. Therefore, we propose a method to estimate the number of information flow sources by multidimensional directed information analysis. In this paper, the effectiveness of the method we proposed has been verified by a simulation, and the method has been applied to EEG of a healthy subject and a patient with a cerebral organic disorder. As a result, we have found that the healthy subject had six information flow sources and the patient had nine.

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The purpose of this study is the development of the device which presents information by using the modulated vibration. However, there has been no study that tried to the evalution of cognition to the modulated vibration in the tactile sensor of human.
In this paper, we propose the method that the cognition level of the discrimination to the modulated vibration stimulus is evaluted based on the Event Related Potential (From now on, it is written with ERP). Modulated vibrations (fH, fL) Hz generated from the high band component fH (from 40, 200Hz) and the low band component fL (from 2, 20Hz). Then, We expressed a certain modulated vibration as 1 point in the frequency area fHvs. fL. We measured the distribution of the discrimination threshold at the frequency area fHvs. fL based on the proposed evalution method by the ERP. As a result of the experiment, it is reported because the effectiveness of the proposal method was confirmed.

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Awake electroencephalographic (EEG) record, which shows background EEG activity and paroxysmal abnormality such as spikes, gives an important information for clinical diagnosis. Especially, an interpretation of spikes is the most important item in diagnosis of subjects with epileptic disorders. A method for automatic interpretation of awake background EEG was already proposed by the authors. However, interpretation of the spikes has not been considered in the previous method. In order to expand the automatic EEG interpretation system as more effective tool in clinical field, the method of automatic EEG spike detection was additionally developed. Integrated automatic EEG interpretation system including spike detection was adopted to the data acquired from 20 subjects. Satisfactory results of the interpretation were obtained for all subjects by comparing with those of visual inspection. Integrated system has achieved a whole interpretation of awake EEG of both background EEG and spikes in paroxysmal abnormality. The method will be a powerful tool for various clinical scene.

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Determination of sleep stages for recorded polysomnogram is an important in clinical diagnosis such as sleep disorders. Visual inspection of polysomnogram consumes much time and is a laborious task. Therefore, many researches on automatic determination of sleep stages have been done in the past. In this study, automatic determination of sleep stages by using the multi-valued decision making method based on conditional probability was proposed. The method was constructed according to the database inspected by an expart and the manner of visual inspection. Proposed method was adopted to the EEG data acquisited from 4 patients, and evaluated by comparing the result of visual inspection. Proposed method was usable for determination of sleep stages, and will be an effective tool for clinical diagnosis.

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To investigate the effects of Extremely Low Frequency ( ELF; 50 - 60 Hz) electric fields on the human brain and nervous system, we developed a telemetry techmique to measure the human electroencephalogram ( EEG ) and electrocardiogam ( ECG ) in a strong ELF electric field and at an altemating high potential. The telemetry system was developed well and the transmitters were small and light enough to measure EEG and ECG without stress. The feasibility of this technique was confirmed by the measurement in a strong ELF electric field Thereafter; using this technique, the EEG and ECG were measured with nine subjects when they were exposed to a strong ELF electric field The data were analyzed by FFT and the spectral powers of the EEG and the Heart Rate Variability were obtained The preliminary results of the EEG and ECG analysis suggested the possibility of the biological effect from the strong ELF electric field exposure.

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In current medical practice, all transmitters, which are used for monitoring ECG, send data continuously. If transmission could be limited to only the ECG data that requires the attention of a technician, the likelihood of interference and power consumption would be reduced considerably. In this paper, I propose a new ECG telemetry system. The transmitter has a simple ECG analyzer, and it only transmits data when abnormal waveforms are detected. As part of this system, we propose a simple algorithm to detect abnormal ECG The algorithm is composed of a baseline drift canceller (utilizing a moving average calculation), a waveform detector (using a modified second order derivative) and an ECG analyzer. In order to test the effectiveness and feasibility of the algorithm, the computer simulations (with a MIT-BIH ECG database) and the experiments (with microprocessor-based hardware) were performed. The results of the simulations are adequate to show that the detection performance and data compression performance of the algorithm. The results of the experiment show that the algorithm even performs adequately when this is used with microprocessor-based hardware that is of limited size or limited power consumption.

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The fetal electrocardiogram is extracted from cutaneous potential recordings of a pregnant woman. The cutaneous potential recordings are noisy mixtures of fetal and maternal source signals. To separate these signals we use time delayed decorrelation, which is an algorithm for independent component analysis. The separated signals are noisy source signals. In order to reduce the noise, we apply nonlinear noise reduction method to the separated fetal component. The extraction of fetal component is sufficiently successful although the fetal signals are much weaker than the maternal ones.

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In the medical field, the measure against noise is one of the most important problems for measurements of signals from the human body. By the existing methods, the artifacts can not be reduced easily. Therefore we have tried to eliminating the artifacts. In this paper, the objective signal is ECG(electrocardiogram). Our purpose is to eliminate the artifact to extract ECG in the input signal which is comprised in EMG (electromyogram). We have adopted the perceptron model with learning for solving this artifact problem. This model which we have designed is able to learn by referring to the target signal. In this paper the first priority is the time for learning. It is the major premise that the error between the target signal and the output signal is minimized. To minimize the time for learning we have kept this model in small parts. This model we have designed is applied to two simulations and one practical problem. As a result of simulation, we have found this model can eliminate about -20dB noise. The results of experiments showed the applicability to the practical use.

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The purpose of this study is to examine the effect of Olfactory Stimulus used aromas during load of stress on the changes of physiological index. Subjects are 14 healthy adults (6 female, 8 male) who have no olfactory defects, and ages are 25.7±5.7 (Mean±SD). SpO₂, HR, SBP&DBP, SPL are estimated as physiological index. Krapelin test (in Japanese) to load stress are used. Aromas used in the experiment are Rosemary operating on the sympathetic nerve and Lavender operating on the parasympathetic nerve. Change of HR is significantly (p<0.05) represented before and after inhalation of aromas. SBP is also significantly (p<0.05) decreased before and after inhalation of aromas. Both SpO₂ and DBP are not significantly changed. The results show that the analysis of physiological index in stress loading suggests the aromas have effect on the autonomic nervous activity. It is suggested that the aromas are effective in stress management.

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There are many studies on the autonomic nervous system, which analyze the function of the autonomic nervous system by measuring pulse rate. However, many of these studies do not include the pulse rate data during under the stress, because it is so difficult to measure the fast change of pulse rate during stress and during body movement caused by the stress. The purpose of this study is to develop the monitor, which can predict the dental emergency. It monitors fast pulse rate change during body movement aroused by stress. Under this condition, we have developed the new algorithms, which can measure instantaneous pulse rate under body movement. On the other hand we have developed the new simulator which generate signals for pulse oxy-meter from the analog wave forms taken from patient. It makes us possible to compare the specification of any kind of pulse oxy-meters. This paper includes the evaluation of the new algorithm from the clinical points and the comparison between our algorithm and the other algorithms on the point of performance for pulse rate counting.

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We examined changes of electroencepharograms (EEGs) and pulse waves while subjects lissten to different type of sound, a white noise and a sine wave. At the same time, we also examined subjective estimations for each sound using a method of sensory inspection, and investigated the relationship between these sounds and subjective estimations. As a result, the power spectrum component of β (P<0.01) wave in EEGs(Fz) increased in listening of unpleasure sounds. While, power spectrum components of α (P<0.01) and θ (P<0.01) waves increased in listening pleasure sounds.

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The inside of the left atrium can be precisely observed by transesophageal echocardiography-inserting an ultrasonic probe into the esophagus. If it is used on a patient with atrial fibrillation, mitral stenosis, etc., a smoke-like echo called the spontaneous echo contrast will be observed. Since it is said that the spontaneous echo contrast is related to thrombosis, an early diagnosis is needed. However, validation procedure is a precedence scale and is not established. We compared a doctor's diagnostic validation with a time shift of picture image power (the near mitral value of a left-atrium picture image), in order to establish the evaluation of the spontaneous echo contrast. Consequently, we have evaluated the spontaneous echo contrast in detail, attained a result which can support a doctor's diagnosis.

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Recently, we are concerned with security because picking and imitation on computer network are increasing. Then, the approach to individual identification from biometric is expected, because it can realize high reliability and it's a natural method.
This paper's proposition is to construct individual identification system with the facial skin thermogram (FST) which is robust about illumination condition. FST has no shadow with illumination because it catches infrared rays light and makes an image. Then, we extract individual feature from FST by image processing and examine evaluation method to identify individual. However, facial skin temperature is ruled by autonomous nerve system. Especially, nasal skin temperature is affected by a mental influence like stress and arousal level. And we limited identification object to the measurement of face image in the rest state.
We applied two dimensional discrete fourier transform (2DDFT) as a method of extracting individual feature, because we tried to convert the individual feature of FST into spatial frequency feature. Afterwards, we identified individual by pattern matching. Identification experiment was done in 30 registered patterns and 200 input patterns, consequently correct acceptance rate 91.0[%] and correct rejection rate 91.0[%] was able to be obtained. Moreover, we confirmed individual feature appeared in low frequency element of FST.

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We developed a new measurement system of pupil area with camera position adjustability using iris diameter, which size is constant regardless of automatic nervous system. The camera probe consists of a small CCD camera, infrared LEDs, and a stepping motor. The motor can adjust camera position to an optimum distance in order to get sharp eye images. Pupillary response to cholinergic antagonist was a diagnostic method for Alzheimer's disease. It is very important for diagnosis of dementia to analyze pupil size precisely. We used the new detection system for the pupil test. In this study, we evaluated the auto focus function by detecting model eyes and patients' eyes. The results by using this system show that the proposed system can measure pupil area accurately.

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In the measurement of dopamine metabolism with [¹⁸F]FDOPA and Positron Emission Tomography (PET), 2-input 3-tissue compartment 5-parameter model is proposed because of the presence of metabolite [¹⁸F]OMFD which breaks through Blood-Brain Barrier and behaves differently to [¹⁸F]FDOPA in the brain. This model has a large number of parameters, and estimated parameters are not precise owing to the noise. Therefore, the reduction of the number of parameters is necessary, and some constraints are used in the quantification of human data. In this study, we investigated the effect of the noise and fixed value of constraint in [¹⁸F]FDOPA kinetic analysis for various constraints, and evaluated the reliability of parameter estimates for each. Simulated time activity curves were generated with the model equation and noise was added depending on the collected total count. Parameters were estimated by the nonlinear least square method with various constrains, and the reliability of parameter estimates was compared. As a result, the reduction of the number of parameter brought about changes in reliability of parameter estimates, and we were able to evaluate which parameter should be fixed for reliable estimation.

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Deformability of erythrocyte is a crucial factor to maintain smooth blood flow in the microcirculation supplying oxygen and nutriments to organic tissues. Decrease in the deformability depends on the elasticity of erythrocyte, especially on the cell membrane structure that leads to high shear stress on the blood vessel wall and significant increase in the flow resistance. In this study, microscopic elastic property of the erythrocyte under diabeteic and another physical conditions were measured by using atomic force microscope (AFM) in the contact mode function. The spring constant k and the Young's modulus E of erythrocytes were derived from the so-called force curve applying the Hooke's law and the Hertz model. In case of the compressing force of AFM at 1.5nN, k and E of healthy erythrocytes were 7-9mN/m and 0.1-0.15MPa while diabetic samples showed significantly higher elasticity than those of healthy samples. This implies the diabetic erythrocytes change to be stiff as the result of glycosylation of cell membrane that may induce microangiopathy.

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We developed a piezoelectric bimorph stirrer for the use of the automatic analyzer where the blood serum filled in a small cuvette could be mixed with reagent in a few second of time. The special feature innovated in the present method is that the stirring blade was vibrated with a mode at semi-2nd resonant frequency, which came into existence by attaching a weight in the middle of stirring bar. The node point of the semi-2nd vibration mode was adjusted at optimum location by changing the amount of weight to get a maximum stirring capability. Use of semi-2nd vibration mode has a advantage that it generates liquid flows in a cuvette toward up and down direction. As a result, unwanted generation of air bubble was avoided, since the solution was mixed with smaller force than before. At the end of this paper, the successful results of the operational suitability test were shown.

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Mushrooms have recently been attracting increasing attention for their use as part of a healthy diet; because they are rich in nutrients while low in calories, they are effective in preventing modern life-style diseases. Accordingly, mushroom farming has increased. In order to increase the productivity of mushroom farming, it is important to study the optimal farming conditions, such as the temperature, humidity, light stimulus, and the composition of the atmosphere, as well as the ingredients of the culture medium. However, these conditions have generally been chosen according to farmers' experiences at the site and few scientific studies have so far been conducted.
We have scientifically investigated the optimum growing conditions of mushrooms focusing on the relationship between the bioelectric potential and the morphogenetic properties. In this study using Grifora Frondosa as a sample, we investigated how the mushroom responds to different wavelengths, luminance, and the irradiation method of the light-stimulus using the bio-electric potential signal as an indicator. The bio-electric potential is estimated to have a close relationship with the activation of the cells. Based on the obtained bio-electric potential data, we experimentally developed a novel light source instrument using a LED for controlling growth, which is effective in forming the fruit-body of the mushroom after development of the primordium at the mushroom growing farm. We report here on the fundamental data concerning the influence of bio-electric potential produced as a result of various light stimuli on the morphogenetic properties of Grifora Frondosa.

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The effects of metal ion concentration in the culture medium of Rahpanus sativus were investigated. A seed of R.sativus is known to uptake metal ion for its root growth, which produces ion influx and electrical potential along the root. However, in the very early stage of root growth, a R.sativus seed releases large amount of metal ion to the ambient medium. The reason and mechanism of this early ion release was still in question. We have examined the root growth of the root with only one or two seeds in a culture bessel, and shown that the single seed cannot grow in small volume culture medium because of the high ion concentration. On the other hand, in case of two seeds, this happened only to one seed and another one grows almost normally. This growth regulation by ion concentration can be explained as a lateral inhibition mechanism of seeds sprayed in a small area.

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We developed fast detecting method to measure influences of chemical substances to plant. Fluorescence from chloroplast was used for the signal from plant. Used chemicals were alleropathy substances, that is extracted from plants and is known as inhibitor of the growth. Fluorescence induction phenomena and frequency responses of fluorescence from pumpkin leaf were measured, while time constants and normalized response value were estimated from time course of fluorescence image. As a result, alleropathy substances affect fluorescence from the leaf and high sensitive and high speed detection is realized. Furthermore, the data is not affected by individual differences of plant and experimental circumstance. Therefore, the present method can be utilized for an index of plant activity.

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