UV-LED irradiation reduces the infectivity of herpes simplex virus type 1 by targeting different viral components depending on the peak wavelength.

Herpes simplex virus type 1 (HSV-1) is an enveloped virus that mainly infects humans. Given its high global prevalence, disinfection is critical for reducing the risk of infection. Ultraviolet-light-emitting diodes (UV-LEDs) are eco-friendly irradiating modules with different peak wavelengths, but the molecules degraded by UV-LED irradiation have not been clarified. To identify the target viral molecules of UV-LEDs, we exposed HSV-1 suspensions to UV-LED irradiation at wavelengths of 260-, 280-, 310-, and 365-nm and measured viral DNA, protein, and lipid damage and infectivity in host cells. All UV-LEDs substantially reduced by inhibiting host cell transcription, but 260- and 280-nm UV-LEDs had significantly stronger virucidal efficiency than 310- and 365-nm UV-LEDs. Meanwhile, 260- and 280-nm UV-LEDs induced the formation of viral DNA photoproducts and the degradation of viral proteins and some phosphoglycerolipid species. Unlike 260- and 280-nm UV-LEDs, 310- and 365-nm UV-LEDs decreased the viral protein levels, but they did not drastically change the levels of viral DNA photoproducts and lipophilic metabolites. These results suggest that UV-LEDs reduce the infectivity of HSV-1 by targeting different viral molecules based on the peak wavelength. These findings could facilitate the optimization of UV-LED irradiation for viral inactivation.

Journal of Photochemistry and Photobiology B: Biology


Identification of Genes Associated with Sensitivity to Ultraviolet A (UVA) Irradiation by Transposon Mutagenesis of Vibrio parahaemolyticu


Development of a novel automatic ascites filtration and concentration equipment with multi-ring-type roller pump units for cell-free and concentrated ascites reinfusion therapy.

Cell-free and concentrated ascites reinfusion therapy (CART) is an effective therapy for refractory ascites. However, CART is difficult to perform as ascites filtration and concentration is a complicated procedure. Moreover, the procedure requires the constant assistance of a clinical engineer or/and the use of an expensive equipment for the multi-purpose blood processing. Therefore, we developed a CART specialized equipment (mobility CART [M-CART]) that could be used safely with various safety measures and automatic functions such as automatic washing of clogged filtration filter and self-regulation of the concentration ratio. Downsizing, lightning of the weight, and automatic processing in M-CART required the use of newly developed multi-ring-type roller pump units. This equipment was approved under Japanese regulations in 2018. In performing 41 sessions of CART (for malignant ascites, 22 sessions; and hepatic ascites, 19 sessions) using this equipment in 17 patients, no serious adverse event occurred. An average of 4494 g of ascites was collected and the total amount of ascites was processed in all the sessions without any trouble. The mean weight of the processed ascites was 560 g and the mean concentration ratio was 8.0. The ascites were processed at a flow rate of 50 mL/min. The mean ascites processing time was 112.5 minutes and a 106.5-minutes (95.2%) ascites processing was performed automatically. The operator responded to alarms or support information 3.2 times on average (3.1 minutes, 2.1% of ascites processing time). Human errors related to ascites processing were detected by M-CART at 0.4 times per session on average and were appropriately addressed by the operator. The frequencies of automatic washing of clogged filtration filter and self-regulation of the concentration ratio were 31.7% and 53.7%, respectively. The mean recovery rates (recovery dose) of protein, albumin, and immunoglobulin G were 72.9%, 72.9%, and 71.2% (65.9 g, 34.9 g, and 13.2 g), respectively. Steroids were administered in 92.7% of the sessions to prevent fever and the mean increase in body temperature was 0.53°C. M-CART is a compact and lightweight automatic CART specialized equipment that can safely and easily process a large quantity of ascites without the constant assistance of an operator.


Inactivation of Extended-spectrum β-Lactamase (ESBL)-producing Escherichia Coli by UVA-LED Irradiation System.

The prevalence of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli is increasing rapidly and spreading worldwide, particularly in Asia, compared to other regions. In the last ten years, in our hospital, in particular, there has been a < 30% increase. To prevent the spread of ESBL in hospitals and the community, the ultraviolet (UV) A-light-emitting diode (LED) irradiation device was used to inactivate ESBL-E. coli in human livestock and the environment. ESBL-E. coli and E. coli bacterial samples were collected from patients at Tokushima University Hospital (Tokushima City, Japan). The UVA-LED irradiation system had 365 nm single wavelength, and the current of the circuit was set to 0.23 or 0.50 A consistently. Results demonstrated that UVA-LED was useful for the inactivation of ESBL-E. coli and E. coli. The minimum energy dosage required to inactivate ESBL-E. coli and E. coli was 40.76 J/cm2 (45 min) in the first type of UVA-LED and 38.85 J/cm2 (5 min) in the second type. There were no significant differences between ESBL-E. coli and E. coli. The inactivation of ESBL-E. coli was dependent on energy. These findings suggest that UVA-LED with 365 nm single wavelength could be useful for surface decontamination in healthcare facilities. J. Med. Invest. 67 : 163-169, February, 2020.

The Journal of Medical Investigation : JMI


多波長植物専用LED照射装置を用いた完全制御型水耕栽培システム

多波長植物専用LED照射装置を用いた完全制御型水耕栽培システム

LED総合フォーラム2019 in 徳島 論文集

LED総合フォーラム2019 in 徳島 論文集


Bacterial Contamination of Hemodialysis Devices in Hospital Dialysis Wards.

Chronic care patients undergoing hemodialysis for treatment of end-stage renal failure experience higher rates of bloodstream-associated infection due to the patients' compromised immune system and management of the bloodstream through catheters. Staphylococcus species are acommon cause of hemodialysis catheterrelated bloodstream infections. We investigated environmental bacterial contamination of dialysis wards and contamination of hemodialysis devices to determine the source of bacteria for these infections. All bacterial samples were collected by the swab method and the agarose stamp method. And which bacterium were identified by BBL CRYSTAL Kit or 16s rRNA sequences. In our data, bacterial cell number of hemodialysis device was lower than environment of patient surrounds. But Staphylococcus spp. were found predominantly on the hemodialysis device (46.8%), especially on areas frequently touched by healthcare-workers (such as Touch screen). Among Staphylococcus spp., Staphylococcus epidermidis was most frequently observed (42.1% of Staphylococcus spp.), and more surprising, 48.2% of the Staphylococcus spp. indicated high resistance for methicillin. Our finding suggests that hemodialysis device highly contaminated with bloodstream infection associated bacteria. This study can be used as a source to assess the risk of contamination-related infection and to develop the cleaning system for the better prevention for bloodstream infections in patients with hemodialysis. J. Med. Invest. 66 : 148-152, February, 2019.


A computer simulation of the metallic artifacts in MRI caused by dental magnetic attachments

Dental magnetic attachments, which are relatively simple to use and provide good retention and stability, have been increasingly used as dental prostheses. These attachments are composed of ferromagnetic stainless-steel keepers and magnetic assemblies embedded in the denture. The use of magnetic resonance imaging (MRI) to investigate lesions in the oral and maxillofacial areas is quite common. When a patient with a magnetic keeper undergoes MRI examination of the oral or maxillofacial area, however, the keeper is considered a metallic artifact (MA). Depending on the location of the lesion requiring diagnosis, the patient may be required to remove the keeper. The extent of the MA is known to be related to the hardware and pulse sequence parameters and the magnetic properties of the keeper. In this study, we propose a new method to estimate the extent of the MA in MR images caused by a keeper placed in the MRI, approximating the keeper with a magnetic dipole. This method should allow us to express the relationship among the hardware and pulse sequence parameters, the magnetic properties of the keeper and the extent of the MA in the MR image. To evaluate the validity of the method, we compare the MA in MR images produced by the proposed method with those in any experimental MR images taken in the existing study. Via our computer simulations, we show that the proposed method outperformed the existing approach and can estimate the extent of the MA based on the hardware and pulse sequence parameters and the magnetic properties of the keeper. By estimating the extent of the MA in the MR image by using our method before the MRI examination, depending on the location of the lesion requiring diagnosis, it may not be necessary to remove the keeper.

歯科用磁性アタッチメントの利用が広がっているが，口腔内に取り付けるキーパーは磁性材料を含むためMRI検査時の金属アーチファクトが問題となる．本研究ではキーパーによる金属アーチファクトの大きさを評価するための手法を提案し，計算機シミュレーションおよび既存の研究結果を用いて有用性を検討している．キーパーはMRIの界磁で磁化するが，キーパーの大きさが解析領域に対して小さい場合は磁気ダイポールにより近似することができる．金属アーチファクトの大きさはキーパーの大きさ・材質およびパルスシーケンスに関係することが示された．

Biomedical Physics & Engineering Express


LED光を用いた対外循環照射モデルの構築.

LED光を用いた対外循環照射モデルの構築.

電子情報通信学会研究技術報告(MEとバイオサイバネティックス)

電子情報通信学会研究技術報告(MEとバイオサイバネティックス)


Evaluation of human bowel motility using non-contact microphones


Automatic snore sound extraction from sleep sound recordings via auditory image modeling

Biomedical Signal Processing and Control


Combined treatment of UVA irradiation and antibiotics induces greater bactericidal effects on Vibrio parahaemolyticus.

The presence of antibiotics in the environment and their subsequent impact on the development of multi-antibiotic resistant bacteria has raised concerns globally. Consequently, much research is focused on a method to produce a better disinfectant. We have established a disinfectant system using UVA-LED that inactivates pathogenic bacteria. We assessed the bactericidal efficiency of a combination of UVA-LED and antibiotics against Vibrio parahaemolyticus. Combined use of antibiotic drugs and UVA irradiation was more bactericidal than UVA irradiation or antibacterial drugs alone. The bactericidal synergy was observed at low concentrations of each drug that are normally unable to kill the bacteria. This combination has the potential to become a sterilization technology. J. Med. Invest. 63: 63-67, February, 2016.


Effects of UV-A LED light irradiation on growth of cultured RAW 264.7 cells

Toxicological and Environmental Chemistry


A computational model for tinnitus generation and its management by sound therapy

International Journal of Biology and Biomedical Engineering


Signal shape feature for automatic snore and breathing sounds classification

In this study we focus on this problem and propose an automated method to classify snore and breathing sounds based on the novel feature, 'positive/negative amplitude ratio (PNAR)', to measure the shape of the sound signal. The performance of the proposed method was evaluated using snore and breathing recordings (snore: 22 643 episodes and breathing: 4664 episodes) from 40 subjects. Receiver operating characteristic (ROC) analysis showed that the proposed method achieved 0.923 sensitivity with 0.918 specificity for snore and breathing sound classification on test data. PNAR has substantial potential as a feature in the front end of a non-contact snore/breathing-based technology for sleep studies.

この論文では，新規信号形状特徴を用いた，いびき•呼吸音の自動分類法を提案する．提案法の性能評価を行った結果，提案法は感度:0.923，特異度:0.918の高精度自動抽出が行える事が分かった．さらに，提案法は，既存法よりも優れた性能を有する事が分かった．


Simultaneous irradiation with different wavelengths of ultraviolet light has synergistic bactericidal effect on Vibrio parahaemolyticus.

Ultraviolet (UV) irradiation is an increasingly used method of water disinfection. UV rays can be classified by wavelength into UVA (320-400 nm), UVB (280-320 nm), and UVC (< 280 nm). We previously developed UVA sterilization equipment with a UVA-light emitting diode (LED). The aim of this study was to establish a new water disinfection procedure using the combined irradiation of the UVA-LED and another UV wavelength. An oxidative DNA product, 8-hydroxy-2'-deoxyguanosine (8-OHdG), increased after irradiation by UVA-LED alone, and the level of cyclobutane pyrimidine dimers (CPDs) was increased by UVC alone in Vibrio parahaemolyticus. Although sequential irradiation of UVA-LED and UVC induced additional bactericidal effects, simultaneous irradiation with UVA-LED and UVC induced bactericidal synergistic effects. 8-OHdG and CPDs production showed no differences between sequential and simultaneous irradiation. Interestingly, the recovery of CPDs was delayed by simultaneous irradiation. The synergistic effect was absent in SOS response-deficient mutants, such as the recA and lexA strains. Because recA- and lexA-mediated SOS responses have crucial roles in a DNA repair pathway, the synergistic bactericidal effect produced by the simultaneous irradiation could depend on suppression of the CPDs repair. The simultaneous irradiation of UVA-LED and UVC is a candidate new procedure for effective water disinfection. This article is protected by copyright. All rights reserved.


体外循環療法中に腎臓で行われる水分の再吸収効率の推定

体外循環療法中に腎臓で行われる水分の再吸収効率の推定


Anxiety affects amplitudes of red and green color-elicited flash visual evoked potentials in humans

It has been reported that negative emotional changes and conditions affect the visual faculties of humans at the neural level. On the other hand, the effects of emotion on color perception in particular, which are based on evoked potentials, are unknown. In the present study, we investigated whether different anxiety levels affect the color information processing for each of 3 wavelengths by using flash visual evoked potentials (FVEPs) and State-Trait Anxiety Inventory. In results, significant positive correlations were observed between FVEP amplitudes and state or trait anxiety scores in the long (sensed as red) and middle (sensed as green) wavelengths. On the other hand, short-wavelength-evoked FVEPs were not correlated with anxiety level. Our results suggest that negative emotional conditions may affect color sense processing in humans.

The Journal of Medical Investigation : JMI


Homeostatic plasticity and spike-time-dependent plasticity in computational modeling of tinnitus generation and its management by sound therapy


Vegetable surface sterilization system using UVA light-emitting diodes.

Surface sterilization of fresh produce has been needed in the food manufacturing/processing industry. Here we report a UVA-LED (Ultra Violet A-Light Emitting Diode) system for surface sterilization that is safe, efficacious, low cost, and apparently harmless to fresh produce. To test the system, Escherichia coli strain DH5 was spot-inoculated onto vegetable tissues, and treated under UVA-LED. Tissues were homogenized and bacteria quantified by colony-forming assay. Possible effects of UVA-LED on vegetable quality were evaluated by HPLC. Tissue weight changes were checked after treatment at 4, 15, and 30. Bacterial inactivation by UVA-LED radiation was observed after a 10 min treatment and increased with increasing time of irradiation. The log survival ratio reached -3.23 after a 90 min treatment. Bacterial cells surviving treatment grew slowly compared to non-irradiated control cells. Cabbage tissue lost weight over time after treatment, and weight loss increased with increasing incubation temperature, but there was no difference between losses by UVA-LED treated and control tissues at any temperature tested. In addition, no differences of Vitamin C content in cabbage tissue were detected by HPLC after UVA-LED treatment. These results suggest that UVA-LED treatment has great potential for vegetable surface sterilization in the food manufacturing/processing industry.


Evaluation of blood flow velocity waveform in common carotid artery using multi-branched arterial segment model of human arteries

Arteriosclerosis is considered to be a major cause of cardiovascular diseases, which account for approximately 30% of the causes of death in the world. We have recently demonstrated a strong correlation between arteriosclerosis (arterial elasticity) and two characteristics: maximum systolic velocity (S1) and systolic second peak velocity (S2) of the common carotid artery flow velocity waveform (CCFVW). The CCFVW can be measured by using a small portable measuring device. However, there is currently no theoretical evidence supporting the causes of the relation between CCFVW and arterial elasticity, or the origin of the CCFVW characteristics. In this study, the arterial blood flow was simulated using a one-dimensional systemic arterial segments model of human artery in order to conduct a qualitative evaluation of the relationship between arterial elasticity and the characteristics of CCFVW. The simulation was carried out based on the discretized segments with the physical properties of a viscoelastic tube (the cross-sectional area at the proximal and terminal ends, the length, and the compliance per unit area of the tube (CS)). The findings obtained through this study revealed that the simulated CCFVW had shape similar characteristics to that of the measured CCFVW. Moreover, when the compliance CS of the model was decreased, the first peak of the simulated-CCFVW decreased and the second peak increased. Further, by separating the anterograde pulse wave and the reflected pulse wave, which form the CCFVW, we found that the decrease in the first peak of the simulated CCFVW was due to the arrival of a reflected pulse wave from the head after the common carotid artery toward the arrival of a anterograde pulse wave ejected directly from the heart and that the increase in the second peak resulted from the arrival of the peak of the reflected pulse wave from the thoracic aorta. These results establish that the CCFVW characteristics contribute to the assessment of arterial elasticity.

総頸動脈血流速度波形と動脈弾性の関係について，1次元流体解析モデルを用いて検討している．動脈モデルはヒトの全身の主要な動脈を多枝セグメントモデルとして構築したものを用い，動脈弾性を変化させた時の総頸動脈の血流速度波形を求めた結果，動脈弾性の変化により血流速度波形が変化することを示した．これにより総頸動脈の血流速度波形を調べることにより動脈硬化を評価することができる可能性を示した．

Biomedical Signal Processing and Control


ARMA based spectral bandwidth for evaluation of bowel motility by the analysis of bowel sounds

In this study we propose a novel simple automatic method to detect the bowel sound(BS)s based on the 3 dB bandwidth of the frequency peaks in the autoregressive moving average spectrum. We use the measure, sound-to-sound interval (SSI) obtained by the proposed method, to capture bowel motility. In this paper, we show that the proposed method for automatic detection could achieve a sensitivity of 87.8±5.88%, specificity of 91.7±4.33% and area under the curve of 0.923 when working on 16 healthy volunteers during mosapride administrations. Furthermore, we show that the measured SSI averaged over a period of 30 min can clearly capture bowel motility. Our findings should have the potential to contribute toward developing automated BS-based diagnosis of IBS.

ARMAスペクトルピークの3dB帯域幅を用いて自動的に腸蠕動音を検出する方法を提案する．提案法の性能評価の結果，提案法は感度:87.8±5.88%，特異度:91.7±4.33%およびAUC:0.923の高精度な自動抽出が行える事が分かった．被験者16人に対して薬剤負荷試験を行い，腸蠕動促進剤摂取前後における腸運動性を腸蠕動音の発生頻度をもとに評価できることが分かった．


Spike-time-dependent plasticity of excitation and inhibition in a neuronal network model for tinnitus relief with sound therapy

International Journal of Biology and Biomedical Engineering


Inactivation of MS2 Phage and Cryptosporidium parvum Oocysts Using UV-A from High-Intensity Light-Emitting Diode for Water Disinfection

In this study, high-intensity, UV-A (ranging from 360 to 370 nm, peak wavelength at 365 nm) produced by a light-emitting diode was used for the inactivation of MS2 phage and Cryptosporidium parvum oocyst. In the irradiation experiment with MS2 phage, approximately 44 and 65 J/cm2 of UV-A were required to obtain -2 and -3 log inactivations, respectively. The -2 and -3 log inactivations of Cryptosporidium oocysts required 338 and 508 J/cm2 UV-A, respectively, which were 7.7 - 7.8 times greater than those required for MS2 phage. The possibility that high-intensity UV-A irradiation can inactivate both protozoa and viruses (phage) was demonstrated in this study.

Journal of Water and Environment Technology


ECG Signal Pre-processing by Lifting Scheme Constructing Multi-resolution Morphological Decomposition

The target for Electrocardiogram (ECG) signal pre-procession was baseline correction and noise suppression with as low as possible waveform distortion. Morphological operations based pre-processing methods had superiority on reducing waveform distortion and computing complexity. However, linear structure element would cause block effect which was the reason for waveform distortion. Therefore, a novel pre-processing method based on lifting scheme constructing multi-resolution morphological decomposition was proposed in this study. The algorithm adopted cubic spline interpolation for design of predicting and updating operators to effectively reduce the block effect. By simulation to standard test ECG signals and comparison with other pre-processing algorithms based on wavelet transform and multi-resolution morphological decomposition, it was concluded that this algorithm could achieve good performance in mean absolute differences, max difference and root mean square error. The waveform distortion was visually acceptable and the computing complexity was not high.

心電図波形の低歪みなベースライン除去および雑音除去について検討している．本研究では多重解像度の形態分解法を応用した手法を提案し，有用性について検討している．


Inhibition of oscillation in a neural oscillator model for sound therapy of tinnitus

International Journal of Modelling and Simulation


Artificial neural networks for breathing and snoring episode detection in sleep sounds

In this paper, we propose a fundamentally novel approach based on artificial neural network (ANN) technology to detect snore and breathing sound episodes(SBE). Working on clinical data, we show that the proposed method can detect SBE at a sensitivity and specificity exceeding 0.892 and 0.874 respectively, even when the signal is completely buried in background noise (SNR < 0 dB). We compare the performance of the proposed technology with those of the existing methods (short-term energy, zero-crossing rates) and illustrate that the proposed method vastly outperforms conventional techniques.

この論文では，ニューラルネットワークを用いたいびき•呼吸音検出法を提案する．提案法はSNR<0dBの状況下でも精度良く，感度:0.892，得意度:0.874で，いびき•呼吸音を検出できることが分かった．さらに，提案法は，既存法よりも優れた性能を有する事が分かった．


Sterilization effect of UV light on Bacillus spores using TiO(2) films depends on wavelength.

UV light and photocatalysts such as titanium dioxide (TiO(2)) and silver (Ag) are useful for disinfection of water and surfaces. However, the effect of UV wavelength on photocatalytic disinfection of spores is not well understood. Inactivation of Bacillus spores has been examined using different UV wavelengths and TiO(2) or TiO(2)/Ag composite materials. The level of UVA disinfection of Bacillus anthracis and Bacillus brevis vegetative cells increased with the presence of the TiO(2) and Ag photocatalysts, but had little effect on their spores. B. brevis spores were slightly more sensitive to UVB and UVC than the spores of B. atrophaeus. Photocatalytic sterilization against spores was strongest in UVC and UVB and weakest in UVA. The rate of inactivation of Bacillus spores was significantly increased by the presence of TiO(2), but was not markedly different from that induced by the presence of Ag. Therefore, TiO(2)/Ag plus UVA can be used for the sterilization of vegetative cells, while TiO(2) and UVC are effective against spores.

The Journal of Medical Investigation : JMI


A plastic neuronal network model with STDP for tinnitus management by sound therapy

International Journal of Mathematical Models and Methods in Applied Sciences


MI sensor-aided screening system for assessing swallowing dysfunction: Application to the repetitive saliva-swallowing test

Assessment of swallowing dysfunction, particularly the risk of aspiration, is extremely important to clinicians because it provides crucial information for preventing morbidity and mortality from dysphagia. The purpose of this study was to describe a magneto-impedance sensor-aided screening system (MISS) for assessing swallowing function and clarify its effectiveness with the repetitive saliva-swallowing test (RSST). An MI sensor attached to the skin over the sternum detected the distance from a magnet attached to the skin over the thyroid cartilage during swallowing as the change of magnetic fields. The MISS was validated by videofluoroscopic and videoendoscopic observations. Further, the swallowing behavior of 93 individuals was assessed by using the MISS and then analyzed with the RSST. Swallowing behavior can be recorded and investigated objectively by signal inspection in the MISS compared with the conventional methods. The MISS is a simple and straightforward method for recording and safe because of dry swallow. The MISS system was validated by using simultaneous recordings with videofluoroscopic or videoendoscopic examinations, and compared with the conventional RSST method. The MISS combined with the RSST is an effective screening test for swallowing function.


High Frequency Region of the Snore Spectra Carry Important Information on the Disease of Sleep Apnea

The traditional approach over the years has been to record snore sounds at a bandwidth of < 5 kHz. In this paper, we compute the power spectra of snores in three different bands defined as: low-frequency band (LFB: < 5 kHz); middle-frequency band (MFB: 5-10 kHz) and high-frequency band (HFB: 10-20 kHz). We illustrate that there is a significant difference between non-OSA snorers (Apnoea Hypopnoea Index (AHI) < 10) and OSA snorers (AHI > 10) in the region > 5 kHz. We then develop a feature to diagnose obstructive sleep apnoea (OSA) based on the spectral differences in the high frequency region and evaluate its performance on a database of 20 subjects.

いびきの周波数スペクトルは5kHz以下で特徴付けられると考えられ，その範囲でOSAいびきと単純いびきが分類できると報告されている．本研究では5kHz以上の高い周波数成分を調査することによりOSAいびきと単純いびきを分類できるかどうか検討を行う．高周波帯域に関する周波数スペクトルの違いを表現する方法を開発し，20人の患者から得られたいびきに対して，その性能の評価を行った．結果として，5kHz以上の周波数帯域にOSAと単純いびき症を識別できる違いがある事を示した．

Journal of Medical Engineering & Technology


Effects of a 1.5 T time-varying magnetic field on cell volume regulation of bovine adrenal chromaffin cells in hyposmotic media.

Effects of a time-varying magnetic field on cell volume regulation by hyposmotic stress in cultured bovine adrenal chromaffin cells were examined. Through regulatory volume decrease (RVD), cell volume of chromaffin cells that were incubated in a hypotonic medium initially increased, reached a peak and finally recovered to the initial value. Two hour exposure to a magnetic field and addition of cytochalasin D increased peak value and delayed return to initial value. Intracellular F-actin contents initially decreased but returned to normal levels after 10 sec. Two hour exposure to the magnetic field and addition of cytochalasin D continuously reduced the F-actin content. Results suggest that exposure to the magnetic field stimulated disruption of the actin cytoskeleton and that the disruption delayed the recovery to the volume prior to osmotic stress.


Feed-forward changes in carotid blood flow velocity during active standing.

Orthostatic changes induce temporary loss of circulatory regulation. Feedback systems react to cardiovascular alterations to compensate for the instability. To clarify the existence of anticipatory cardiovascular regulation during active standing, we continuously recorded blood flow velocity (BFV) in the common carotid artery and cerebral blood volume (CBV) in healthy men. The maximum BFV value decreased significantly before standing in the reaction-time condition. The decrease significantly correlated with the change in systolic blood pressure that accompanies upright standing from a supine position. The anticipatory BFV decrease disappeared during self-paced standing, and all BFV parameters significantly declined after the self-paced standing. The CBV recording showed a significant increase in oxyhemoglobin levels before standing in the reaction-time condition. Our study suggests that some feed-forward cardiovascular regulation triggered by central command could be activated before standing, and it may play a functional role in the maintenance of cerebral perfusion during standing.


Testing the system non-linearity in snoring sound via neural networks

Snoring has been analyzed for the clinical diagnosis of obstructive sleep apnea(OSA). Snores are likely to have diagnostically relevant non-linearities that cannot be captured by linear techniques. In this paper, we investigate the non-linearity of snores and develop a novel measure, as a possible characterisation index. The method is based on artificial neural networks (NN). The developed method was tested on a database of 27 subjects.

いびきは既存の線形手法で捉えることの出来ない非線形性を有すると考えた．ニューラルネットワーク(NN)を用いていびきの非線形性を調査する方法を開発し，開発した方法が閉塞型睡眠時無呼吸(OSA)いびきと単純いびきに対して検定を行った．27人の患者から得られたいびきに対して非線形性の検定を行うことにより，OSAいびきは単純いびきに比べて，強い非線形性を示すことが分かった．現在までに，いびき解析に基づOSA診断法が提案されているが，非線形性検定はこの方法の更なる性能向上に役立つと思われる．

International Journal of Medical Engineering and Informatics


A Neural Oscillator Model for Tinnitus and Its Management by Sound Therapy

International Journal of Modern Engineering


The removal of EMG in EEG by neural networks

In this paper, it is presented that electromyography (EMG) is a shot noise based on the generation of EMG. A novel filter is proposed by applying a neural network (NN) ensemble where the noisy input signal and the desired one are the same in a learning process. Both incremental and batch mode are applied in the learning process of NNs that is better than generalized NN filters. This NN ensemble filter not only reduces additive and multiplicative white noise inside signals, but also preserves the signals' characteristics. In clinical EEG and EMG signals processing, the filter is capable of reducing EMG in the clinical EEG, and it is proved that there is randomness in EMG.

EEGとEMGが混在する信号から，EMGを軽減するための新規フィルタを提案する．提案フィルタはニューラルネットワークを用いて作成される．提案フィルタの有効性が周波数スペクトル上で表現される．


A neuronal network model for tinnitus and its management by sound therapy

International Journal of Biology and Biomedical Engineering


Differences in stress response after UVC or UVA irradiation in Vibrio parahaemolyticus.


Basic study of a diagnostic modality employing a new electrical impedance tomography (EIT) method for noninvasive measurement in localized tissue

The objective of this study is to develop a device for noninvasive local tissue electrical impedance tomography (EIT) using divided electrodes with guard electrodes and to validate its effectiveness using bioequivalent phantoms. For this purpose, we prepared a measurement device and bioequivalent phantoms, measured the electrical characteristics of the phantoms, and validated the method using the phantoms. Monolayer phantoms mimicking the brain and muscle and bilayer phantoms consisting of muscle and brain layers were prepared. The relative differences between the measured electrical conductivities of the monolayer brain and muscle phantoms and the true values determined by the 4-electrode method were both less than 10%. The relative differences between the measured and true values in the bilayer phantoms were less than 20% in both layers. The biological impedance measurement device that we developed was confirmed to be effective for impedance measurement in bilayer phantoms with different electrical impedances. To develop a device for the early diagnosis of breast diseases, the development of a multi-layer phantom and demonstration of the effectiveness of the device for its examination are necessary. If the device that we developed makes impedance measurement in breast tumors possible, it may be used as a new diagnostic modality for breast diseases.

The Journal of Medical Investigation : JMI


EFFECTS OF EXPOSURE TO TIME-VARYING 1.5 T MAGNETIC FIELD ON VOLUME REGULATION OF BOVINE ADRENAL CHROMAFFIN CELLS

Proceedings of The Bioelectromagnetics Society 32nd Annual Meeting


Development of a High Precision Body Surface Electrocardiogram

高精度体表面心電計の開発と計測

In the 12-lead electrocardiograph currently being used general medical practice, electrodes are positioned at 6 locations in the chest region and the cardiac potential is measured. This research increases the number of electrode to 124 at evenly-spaced intervals over the body surface of the chest, side and back. The commonly used band elimination filter is not used as a countermeasure for exclusion of the noise from such electrodes, and a body surface electrocardiograph has been developed that makes it possible to perform high-speed sampling of the cardiac potential at 80-100 times the conventional rate. From the sampling data obtained with high spatial resolution, maps and animations of the body surface potential distribution are created and displayed from the 1dimension waveform as well as from the 2dimensions/3dimensions waveforms.

現在12誘導心電図が広く使われているが，電極数を124チャネルに増やしたの高精度体表面心電計を開発し，有用性について示した．また入力部の周波数フィルタを使用しないことで，高サンプリング周波数でなおかつ波形の歪みの少ない測定結果が得られることを示した．測定結果から体表面の電位マップを表示した．

IEEJ Transactions on Electronics, Information and Systems

電気学会論文誌C (電子，情報，システム部門誌)


A new colored beverage disinfection system using UV-A light-emitting diodes

In this study we evaluated the ability of the UV-A-LED to eliminate bacteria in a colored beverage. Ten edible pigments were used to make a colored solution at concentrations of 1.0%, 0.1%, 0.01% and 0.001%. We used a colony-forming assay to monitor the bactericidal action against the bacteria. The bactericidal effect of UV-A-LED against Escherichia coli DH5 a decreased with the increasing concentration of almost all of the edible pigments. Although less effective in colored solutions and commercially available orange juice than in the positive control PBS, it holds potential for further development and use to ensure food and water safety.


個人のコンテキスト情報に基づく動的多重帰属グループサービスの提案

個人のコンテキスト情報に基づく動的多重帰属グループサービスの提案

The diversification of the network service has been proceeding so that it may be seen in the development of cloud computing and NGN, the diffusion of wide area Ethernet and the wireless LAN service, and so on. That is, the ubiquitous environment where a network can be used always anywhere easily is becoming common. As for the individual work style, business in the ubiquitous environment has been getting possible in the same way. On the other hand, when a future aging society with fewer children and the diversification of the lifestyle are put into a view, it is thought that being related with not only the inside of a company but society or an area becomes important also for the individual activity. In this paper, "service which supports the individual activity with an information system" is proposed as service which made the network and the information system newly cooperate based on such a background. That is, activity in the company to which an individual belongs, and the activity in society and the area are regarded as group activity on an information system, and the service which supports these is proposed. The dynamic multi-homing group service which specifically supports the individual activity according to the TPO conditions which are the context information was proposed, and the requirement definition for service realization and architecture were shown. In realization of this service, the contention control function between groups to manage automatically the relation between an individual and two or more organizations is key technology, and the hybrid control system was newly proposed. About these, the prototype system was developed and effectiveness of proposal service was clarified.

クラウドコンピューティングやNGNの進展,広域イーサネットや無線LANサービスの普及等に見られるようにネットワークサービスの多様化が進んでいる.すなわち,いつでもどこでも容易にネットワークが利用できるユビキタス環境が一般化してきている.個人のワークスタイルも,これまでの時間や場所の枠を越えた形態が可能になっている.一方,今後の少子高齢化社会,ライフスタイルの多様化等を視野に入れた場合,個人の活動も企業内だけでなく,社会や地域との関わり合いが重要となる.本論文では,このような背景をふまえ,新たにネットワークと情報システムを連携させたサービスとして個人の活動を情報システムで支援するサービスを提案するものである.すなわち,個人が所属する企業での活動や社会・地域における活動を情報システム上のグループ活動としてとらえ,これらを支援するサービスの提案を行う.具体的には,個人の活動をそのコンテキスト情報であるTPO条件(Time:時間,Place:場所,Occasion:状況)に応じて支援する動的多重帰属グループサービスを提案し,サービス実現のための要件定義,アーキテクチャを示した.本サービスの実現においては,個人と複数の組織との関係を自動的に管理するグループ間競合制御機能がキー技術であり,新たにハイブリッド制御方式を提案した.これらに関して,プロトタイプシステムを開発し,提案サービスの有効性を明らかにした.

Transactions of Information Processing Society of Japan


Discriminating apneic snorers and benign snorers based on snoring formant extracted via a noise-robust linear prediction technique

Snoring is the earliest and the most common symptom of Obstructive Sleep Apnea (OSA) . Quantitative analysis of snoring, however, is not used at present in the clinical diagnosis of the disease. Several researchers have reported differences in the formant frequencies of Apneic and benign snoring sounds (SS) based on linear prediction coding (LPC) analysis. However, SS is complex signal and at local low signal to noise ratio (SNR) . This signal complexity should reduce the accuracy of formant estimation. In this paper, we propose a novel approach to the diagnosis of OSA based on the formants of SSs, extracted via a noise-robust linear prediction technique. The proposed method and existing LPC-based method are compared via a measure, ς which indicates the standard deviation of first formant frequencies. The performance of the proposed method was evaluated on a database of clinical snoring sounds recorded overnight in the laboratory of a hospital sleep diagnostic center. Compared with existing LPC-based method, we show that the proposed method can differentiate (sensitivity: 88.9%, specificity: 88.9%, AUC: 0.85) between benign snoring (Apnea Hypopnea Index, AHI=6.0±3.2 event/h; 6188 episodes) and apneic snoring (AHI=40.7±20.2 event/h; 14066 episodes) .

この論文では，自己相関関数の雑音低減能力を用いて，いびきのホルマント周波数抽出法の雑音耐性を向上させる方法を提案する．18人の患者のいびきに対して，提案法の有効性を確認する事が出来た．ROC解析を用いて，いびきの第一ホルマント周波数に基づく閉塞型睡眠時無呼吸(OSA)の診断における診断能の評価を行い，高い診断能(感度:88.9%，特異度:88.9%，AUC:0.85)を得ることができた．

Transactions of the Japanese Society for Medical and Biological Engineering


Linear neural networks for spectral envelope estimation

The spectral envelope is mainly determined by the shape of vocal tract and it is generally represented by linear estimation methods such as an autoregressive (AR) modeling. Neural network (NN) is general tools for modeling nonlinear function. Nonlinear aspects of NN have been emphasized. However, in this study, a novel approach to spectral estimation, which is based on the use of a linear feed-forward NN is discussed. Example of the linear network for estimating the spectral envelope of vowel sound is presented. The proposed linear NN technique leads to interesting new paradigms which could not have been considered in advance.

線形ニューラルネットワークを用いてスペクトル包絡を推定する方法を提案する．母音を用いて，提案法の有効性が評価される．


Suitability of ultraviolet(A)-light emitting diode for air stream disinfection --- 流動する空気中にUVA-LEDを置いた際の大腸菌(DH5alpha)の活動について調べている．UVA-LEDの発光波長は365nmであり，放射照度は1.2mW/cm2(連続)または0.2mW/cm2(パルス)とした．大腸菌はエアロゾル状にしてダクトの中を通過させた．実験の結果，殺菌効果を確認できた．

We previously developed a high powered light-emitting diode device capable of discharging germicidal ultraviolet irradiation (UVA-LED) at an approximate wavelength of 365 nm. This study examined the bactericidal activity of UVA-LED in moving air streams. Aerosols of Escherichia coli DH5alpha were exposed to UVA-LED irradiation using a stable current (0.5 A and 1.2 mW/cm(2)) or pulse current (1.0 A and 0.2 mW/cm(2)). Settle plate analysis was used for bioaerosol sampling, where results were expressed as Colony Forming Units. A -3 Log inactivation of the E. coli population occurred after 75 minutes of constant exposure to stable current. The pulse current produced inactivation within a similar timeframe. Our results might be significant as a basic study for further investigations about the effect of UVA-LED on airborne bacteria and its suitability for air disinfection applications.

The Journal of Medical Investigation : JMI


携帯型血流計装置の開発とその応用

携帯型血流計装置の開発とその応用


Analyses of Leakage Flux for a Sandwichi Type of Magnetic Attachment

サンドイッチ型磁性アタッチメントの漏れ磁界解析

磁性アタッチメントの臨床使用が広がるにつれて，磁性アタッチメントの近傍に漏洩する磁界が口腔内組織に及ぼす影響が懸念されるようになってきた． 磁性アタッチメントの口腔内の漏洩磁界の評価は重要な課題である．本研究ではカップヨーク型磁性アタッチメントの磁界暴露量の2つの側面があるが， 最初に必要なのは磁界暴露量の評価である． 本論文では， サンドイッチ型の漏れ磁界の大きさとICNIRP(国際非電離放射線防護委員会)およびWHO(世界保健機関)で提唱されている防護指針で設定されている磁界安全基準(40mT)を比較し， 安全性について検討した．

The Journal of the Japanese Society of Magnetic Applications in Dentistry


Effects of exposure to an extremely low frequency-electromagnetic field on the cellular collagen with respect to signaling pathways in osteoblast-like cells.

The effect of exposure to extremely low frequency-electromagnetic field (ELF-EMF: 3 mT, 60 Hz) on differentiation of mouse osteoblast-like MC3T3-E1 cells was examined together with addition of insulin-like growth factor I (IGF-I). As a marker of the differentiation, the cellular collagen content was determined by the absorbance of Sirius red-stained cells measured at the wavelength of 510-520 nm with an imaging microspectroscopy. Exposure to ELF-EMF increased significantly the collagen in the cells. Treatment with PD98059, an inhibitor of extracellular signal-regulated kinase 1/2 (ERK1/2) activation, reduced the collagen in all of the cells examined on control, IGF-I addition and ELF-EMF exposure, however, PD98059 did not prevent the increase in the collagen caused by ELF-EMF exposure, and IGF-I also increased the collagen in the presence of the inhibitor. When phosphatidylinositol 3-kinase (PI3K) pathway was inhibited by LY294002, the increase in collagen induced by ELF-EMF exposure was accelerated, however, the increase in collagen observed by IGF-I addition was suppressed. Treatment with SB203580, an inhibitor of p38 mitogen-activated protein kinase (p38 MAPK), suppressed the increase in the collagen induced by ELF-EMF exposure, whereas IGF-I addition increased the collagen in the presence of the inhibitor. These results suggested that collagen synthesis stimulated by ELF-EMF exposure was carried out by the participation of p38 MAPK pathway, and that PI3K pathway may have the role to suppress the collagen synthesis induced by ELF-EMF exposure, and that the suppression of the PI3K pathway may allow the acceleration of the collagen synthesis.

The Journal of Medical Investigation : JMI


Collection of information on equipment and an alarm monitoring system for an intensive care area

集中治療分野における医療機器情報の収集および警報情報のモニタリングシステム

For improving the working efficiency and preventing the accident, the necessity for the digitization and the conversion to a database of medical information and the analysis to the acquired data in the medical institution has been increasing recently. In the Intensive Care Unit (ICU) and the High Care Unit (HCU), development of the system to monitor and to make database from the information on the medical equipment used to care of the patient is required. Especially, information acquired by the monitoring from the ventilator relates to the life support of the patient directly and the vital monitor that shows the state of the patient is required. Monitoring to the other medical equipments such as the infusion pump, the artificial dialyzer and the Intra-aortic Balloon Pumping (IABP) device that have alarm function is also important, because alarm information in the ICU is useful to prevent the incident and the accident. In this report, we have developed the monitoring system and the Data Collection Interface (DCI) to collect the information on the medical equipments in the ICU. The DCI collects digital data from the equipments and sends it to the system. Using the data, the system has become possible to monitor the states of alarm and abnormality of the equipment in the ICU.

医療機関における効率性や安全性の確保のため，施設内の情報の電子化やデータベースの構築，または情報の分析に対する関心が高まっている．集中治療分野においても入院患者の治療に用いられている医療機器の情報を統合的にモニタリングし，その情報を収集・データベース化するためのシステムの開発が求められている．ICUやHCU等で用いられる医療機器においては，入院患者の生命維持に直接関係する人工呼吸器や患者の状態を示す生体情報モニタの状態をモニタリングするとともに，収集された情報を分析しその結果を治療に役立てることが望まれる．その他，輸液ポンプ，人工透析装置，IABP等警報装置を備えた医療機器の情報を活用し，事故の予防に役立てる試みについても関心が広がっている．本研究では，ICUにおける医療機器の情報を収集し，機器の異常や警報の発生をモニタリングするためのデータ収集用インターフェースとシステムを開発したので報告する．


Dental Magnetic Attachment --- Toward third generation devices

IEEE Transactions on Biomedical Engineering


Optimization of MLP/BP for character recognition using a modified alopex algorithm

It is difficult to determine the recognition mechanism in the neurons of a neural network trained for pattern recognition due to the non-linear nature of neural networks. This paper describes a recognition mechanism of a four-layer back propagation neural network using Alopex algorithm. We have developed a small-scale, four-layered neural network model for simple character recognition, which can recognize the patterns transformed by affined conversion. Alopex algorithm is an iterative and stochastic processing method, which was proposed for optimization of a given cost function. In this case the receptive fields of the neurons in the output layers are obtained using the Alopex algorithm.

Alopex法を用いた4層ニューラルネットワーク認識機構の解明について検討している．位置ずれ，傾きのある文字画像認識のための小規模な4層ニューラルネットワークを構築し，Alopex法を用いて各出力層ユニットの受容野の解析を行った．

International Journal of Knowlrge-based and Intelligent Engineering Systems


Development of a new water sterilization device with a 365 nm UV-LED

Suitability of an ultraviolet light-emitting diode at an output wavelength of 365 nm (UVA-LED) as a sterilization device was examined in comparison with the other wavelength irradiation such as 254 nm (a low-pressure mercury lam) and 405 nm (LED). The proposed system using the UVA-LED was able to inactivate bacteria, such as Escherichia coli DH5 alpha, Enteropathogenic E. coli, Vibrio parahaemolyticus, Staphylococcus aureus, and Salmonella enterica serovar Enteritidis. The inactivations of the bacteria were dependent on the accumulation of UVA irradiation. Taking advantage of the safety and compact size of LED devices, we expect that the UVA-LED sterilization device can be developed as a new type of water sterilization device.

波長365nmのUV-LEDの殺菌装置への適用可能性について，他の波長の光源と比較して検討した．UVA-LEDを使った提案装置は大腸菌DH5α，腸内病原性大腸菌，腸炎ビブリオ，黄色ブドウ球菌，サルモネラ・エンテリカ血清型エンテなどの細菌を不活性化することができた．殺菌効果はUVA照射の蓄積に依存していた．UVA-LEDの安全性や省スペース性を生かし，新しい殺菌装置として使用できることが期待できる．

Medical and Biological Engineering and Computing


New water disinfection system using UVA-light emitting diodes.

To evaluate the ability of high-energy ultraviolet A (UVA) light-emitting diode (LED) to inactivate bacteria in water and investigate the inactivating mechanism of UVA irradiation. We developed a new disinfection device equipped with high-energy UVA-LED. Inactivation of bacteria was determined by colony-forming assay. Vibrio parahaemolyticus, enteropathogenic Escherichia coli, Staphylococcus aureus and Escherichia coli DH5alpha were reduced by greater than 5-log(10) stages within 75 min at 315 J cm(-2) of UVA. Salmonella enteritidis was reduced greater than 4-log(10) stages within 160 min at 672 J cm(-2) of UVA. The formation of 8-hydroxy-2'-deoxyguanosine in UVA-LED irradiated bacteria was 2.6-fold higher than that of UVC-irradiated bacteria at the same inactivation level. Addition of mannitol, a scavenger of hydroxyl radicals (OH(*)), or catalase, an enzyme scavenging hydrogen peroxide (H(2)O(2)) to bacterial suspensions significantly suppressed disinfection effect of UVA-LED. This disinfection system has enough ability to inactivate bacteria and OH(*) and H(2)O(2) participates in the disinfection mechanism of UVA irradiation. We newly developed UVA irradiation system and found that UVA alone was able to disinfect the water efficiently. This will become a useful disinfection system.


Exercise Improved Age-associated Changes in the Carotid Blood Velocity Waveforms

Journal of Biomedical & Pharmaceutical Engineering


Analyses of Leakage Flux for a Cup Yoke Type of Magnetic Attchment

カップヨーク型磁性アタッチメントの漏れ磁界解析

The Journal of the Japanese Society of Magnetic Applications in Dentistry


A Plastic Neural Network Model of Sound Therapy of Tinnitus

IEEJ Transactions on Electrical and Electronic Engineering (TEEE)


Influence of Lipid Emulsion for the Hematocrit Value Measured With Continuous Hematocrit Monitor.

Continuous monitoring of hematocrit with a CRIT-LINE monitor (CLM) is used to prevent excess ultrafiltration during hemodialysis and continuous renal replacement therapy. The presence of substances affecting the scattering and absorption rates of multiple wavelengths of near infrared rays of CLM in the blood may affect the measured values with CLM. We examined the influences of lipid emulsion (LE) on hematocrit and relative blood volume (RBV) which were measured with CLM using an in vitro experimental model with human blood. Additions of 10% or 20% of LE increased the hematocrit measured by LCM and decreased the percent change of RBV in proportion to the dose. One percentage of 20% LE in the plasma increased the expected hematocrit measured with CLM by 2.9%. The decrease of initial hematocrit from 48.1% to 43.4% decreased the expected percent change of RBV from -3.4% to -3.7% with the addition of 1 ml of 20% LE to 100 ml blood. These findings indicate that additions of LE increase hematocrit that is measured with CLM in proportion to the dose of LE. Low levels of initial hematocrit will increase the degree of expected percent change of RBV. Attention should be paid to the influence of LE during monitoring with CLM.


Measurement of Blood Flow Velocity Waveforms in the Carotid, Brachial and Femoral Arteries during Head-up Tilt


Influence of leukocytapheresis therapy for ulcerative colitis on anemia and hemodynamics.

In Japan, leukocytapheresis (LCAP) therapy has been carried out for ulcerative colitis as an effective therapy with a low incidence of side-effects. In the present study, we serially investigated the influence of LCAP therapy on anemia and hemodynamics in patients with ulcerative colitis using a non-invasive method with a Crit-Line monitor (CLM) (Hema Metrics Inc., Salt Lake City, UT and Boston, MA, USA). We carried out LCAP on 10 patients with ulcerative colitis using a CS-100 Cellsorba EX LCAP filter in 34 courses of LCAP. The mean hematocrit value, which was measured using the Crit-Line monitor, was 21.8 +/- 0.2% (21.0-22.4%), which showed no significant changes after each LCAP therapy. The actual erythrocyte count, hemoglobin and hematocrit values decreased by 244 000/mm3, 0.7 g/dL and 2.1%, respectively, however, the differences were insignificant. These values corresponded to 7.8, 8.0 and 7.6% of the values before LCAP, respectively. There were no significant changes in systolic blood pressure, diastolic blood pressure, or heart rate during LCAP. The results of this study suggest that one course of LCAP does not exacerbate anemia, and it does not influence hemodynamics. However, considering the exacerbation of anemia in patients with severe ulcerative colitis caused by massive melena, monitoring with a less invasive Crit-Line monitor and a vital information monitor might be useful.


Basic Studies on Dynamics for an Overdenture Retained by a Magnetic Attachment

磁性アタッチメントで維持されたオーバーデンチャーの力学的特性に関する基礎的考察


Accuracy of Two-Dipole Source Localization Using a Method Combining BP Neural Network with NLS Method from 32-Channel EEGs

The electroencephalogram (EEG) has become a widely used tool for investigating brain function. Brain signal source localization is a process of inverse calculation from sensor information (electric potentials for EEG) to the identification of multiple brain sources to obtain the locations and orientation parameters. In this paper, we describe a combination of the backpropagation neural network (BPNN) with the nonlinear least-square (NLS) method to localize two dipoles with reasonable accuracy and speed from EEG data computerized by two dipoles randomly positioned in the brain. The trained BPNN, obtains the initial values for the two dipoles through fast calculation and also avoids the influence of noise. Then the NLS method (Powell algorithm) is used to accurately estimate the two dipole parameters. In this study, we also obtain the minimum distance between the assumed dipole pair, 0.8cm, in order to localize two sources from a smaller limited distance between the dipole pair. The present simulation results demonstrate that the combined method can allow us to localize two dipoles with high speed and accuracy, that is, in 20 seconds and with the position error of around 6.5%, and to reduce the influence of noise.

IEICE Transactions on Information and Systems


Tracking the states of a nonlinear and nonstationary system in the weight-space of artificial neural networks

The new proposed method uses the connection-weight-space (CWS) of the neural network(NN) to extract information about the signal generator mechanism. We define a novel feature to measure the separation of two arbitrary states in the CWS and use it to track the state changes of the generating system. The performance of the method is examined via synthetic signals and clinical EEG. Synthetic data indicates that the feature can track the system down to a SNR of 3.5 dB. Clinical data obtained from three patients undergoing carotid endarterectomy of the brain showed that EEG could be modeled by the proposed method, and the blood perfusion state of the brain could be monitored via feature, with small NNs.

信号を生成するシステムをモデルしたニューラルネットワーク(NN)の結合荷重空間において，2つの状態を分離する方法を提案する．提案法はSNR=3.5dBの環境下でさえ，システムの状態を捉える事が示唆された．提案法を用いて，動脈内膜切除中のEEG信号をモデルすることにより，血液かん流の状態をモニタリングできることが分かった．

Medical and Biological Engineering and Computing


A Theoretical Study about Parameter Estimation of Space Distributed Local Tissue Impedance

空間分布する局所組織インピーダンスのパラメータ推定に関する理論的検討

In this paper, a new configuration of the electrodes, called divided electrode, is proposed for a short time measurement of bio-impedance in a cross section of a local tissue. Its capability is examined by computer simulations, where a distributed equivalent circuit is used as a model of the tissue. Estimation of impedance parameters is carried out by use of the Gauss-Newton Method. As a result of them, usefulness of the proposed method is confirmed by computer simulations using a typical layered tissue model.

IEEJ Transactions on Electronics, Information and Systems

電気学会論文誌C (電子，情報，システム部門誌)


Brain source localization for two dipoles using a combined method from EEG topography

Estimating the correct location of electric current source with the brain from electroencephalographic (EEG) recordings is a challenging analytic and computational problem. Specifically, there is no unique solution and solutions do not depend continuously on the data. This is an inverse problem from EEG to dipole source. In this paper we consider a method combining backpropagation neural network (BPNN) with nonlinear least square (NLS) method for source localization. For inverse problem, the BP neural network and the NLS method has its own advantage and disadvantage, so we use the BPNN to supply the initial value to the NLS method and then get the final result, here we select the Powell algorithm to do the NLS calculating. All these work are for the fast and accurate dipole source localization. The main purpose of using this combined method is to localize two dipole sources when they are locating at the same region of the brain. The following investigations are presented to show that this combined method used in this paper is an advanced approach for two dipole sources localization with high accuracy and fast calculating.

BPNNとNLS法を組み合わせた信号源推定法について述べている．BPNNはNLS法への適切な初期値を設定するために利用している．シミュレーションの結果，有用であることが確認された

GESTS International Transactions on Computer Science and Engineering


Effects of ELF magnetic fields on signal transduction in osteoblast-like cells

培養骨芽細胞のシグナル伝達に及ぼすELF磁界の影響

日本生体磁気学会誌 特別号 第20回日本生体磁気学会論文集

日本生体磁気学会誌 特別号 第20回日本生体磁気学会論文集


Neural networks for event extraction from time series: a back propagation algorithm approach


Effects of a time-varying strong magnetic field on transient increase in Ca2+ release induced by cytosolic Ca2+ in cultured pheochromocytoma cells

Exposure of pheochromocytoma (PC 12) cells to a time-varying 1.51 T magnetic field inhibited an increase in the intracellular Ca2+ concentration ([Ca2+]i) induced by addition of caffeine to Ca(2+)-free medium. This inhibition occurred after a 15-min exposure and was maintained for at least 2 h. [Ca2+]i sharply increased in cells loaded with cyclic ADP-ribose, and 2-h exposure significantly suppressed the increase. Addition of ATP induced a transient increase in intracellular Ca2+ release mediated by IP3 receptor, and this increase was strongly inhibited by the exposure. Results indicated that the magnetic field exposure strongly inhibited Ca2+ release mediated by both IP3 and ryanodine receptors in PC 12 cells. However, thapsigargin-induced Ca2+ influx (capacitative Ca2+ entry) across the cell membrane was unaffected. The ATP content was maintained at the normal level during the 2-h exposure, suggesting that ATP hydrolysis was unchanged. Therefore, Mg2+ which is known to be released by ATP hydrolysis and inhibit intracellular Ca2+ release may not relate the exposure-caused inhibition. Eddy currents induced in culture medium appear to change cell membrane properties and indirectly inhibit Ca2+ release from endoplasmic reticulum and other Ca2+ stores in PC 12 cells.

Biochimica et Biophysica Acta (BBA) - General Subjects


Basic study of new diagnostic modality according to non-invasive measurement of the electrical conductivity of tissues

The purposes of this study were to estimate the electrical conductivity of tissues by non-invasively measuring the electrical bio-impedance, to develop a new method for tissue diagnosis, i.e., electrical impedance tomography (EIT). Tissue models were first designed taking into consideration the distribution of the fat tissue, muscle and bone in the human forearm, and then the intra-tissue distributions of electrical potential and field, and the electrical impedance in the models was theoretically analyzed by the three-dimensional finite element method. The electrical impedance of both forearms was measured in healthy human subjects, and estimated the electrical conductivity of individual local tissues. The results of the analysis showed that the distributions of electrical potential and field were affected by the presence of fat tissue but not by the presence or absence of bone. In addition, as a result of calculation of the electrical resistance of the extracellular fluid (Re) in each model, it was found that the value of bio-impedance was influenced by the presence of fat tissue, and the value of bio-impedance was increased by the intervention of a fat layer. The electrical conductivity estimated by fitting the observed values to the values obtained by finite element analysis was 0.40 S/m and 0.15 S/m for male muscle and fat tissue, and 0.35 S/m and 0.11 S/m for female muscle and fat tissue, respectively. The sex difference in the slope of linear approximation in the estimation of electrical conductivity of the males and females was thought to be due to sex differences in the properties and structure of fat tissue. These results suggest that local tissues can be diagnosed differentially and electrically by percutaneous measurement of local bio-impedance and subsequent estimation of the electrical conductivity of each tissue.

The Journal of Medical Investigation : JMI


Development of real-time intra-operative analysis software for brain activity using measured EEG

術中脳活動リアルタイム解析ソフトウェアの開発

頸動脈内膜剥離術等のある種の手術では脳への血流を一時的に遮断する必要がある場合がある．このような場合脳の状態のリアルタイムモニタリングは安全性確保のためにを重要な役割を担っている．本研究では計測した脳波から波形表示，周波数解析，DRT(変化率2次元脳電図)表示，警告音の発生などを行うシステムをPC上で構築した．また新たな脳波解析手法として移動平均型ニューラルネットワークを用いた方法を提案し，臨床データを用いて解析を行った．

Transactions of the Japanese Society for Medical and Biological Engineering


Multi-dipole sources identification from EEG topography using system identification method

The goal of source localization in the brain is to estimate a set of parameters for representing source characteristics; one of such parameters is the source number. We here propose a method combining the Powell algorithm with the information criterion method for determining the optimal dipole number. The potential errors can be calculated by the Powell algorithm with the concentric 4-sphere head model and 32 electrodes, then the number of dipoles is determined by the information criterion method with the potential errors mentioned above. This method has the advantages of a high identification accuracy of dipole number and a small number of EEC data because in this method: (1) only one EEG topography is used in the computation, (2) 32 electrodes are used to obtain the EEG data, (3) the optimal dipole number can be obtained by this method. In order to prove our method to be efficient, precise and robust to noise, 10% white noise is introduced to test this method theoretically. Some investigations are presented here to show our method is an advanced approach for determining the optimal dipole number.

IEICE Transactions on Information and Systems


A New Method for Noninvasive Measurement of Multilayer Tissue Conductivity and Structure Using Divided Electrodes

This paper outlines a new method for measuring multilayer tissue conductivity and structure by using divided electrodes, in which current electrodes are divided into several parts. Our purpose is to estimate the multilayer tissue structure and the conductivity distribution in a cross section of the local tissue by using bioresistance data measured noninvasively. The effect of the new method is assessed by computer simulations using a typical two-dimensional (2-D) model. In this paper, the conductivity distribution in the model is analyzed based on a finite difference method (FDM) and a steepest descent method (SDM). Simulation results show that the conductivity values of skin, fat, and muscle layers can be estimated with an error of less than 0.1%. When random noise at various levels is added to the measured resistance values, estimates of the conductivity values for skin, fat, and muscle layers are still reasonably precise: their root mean square errors are about 1.06%, 1.39%, and 1.61% for 10% noise. In a 2-D model, increasing the number of divided electrodes permits simultaneous estimates of tissue structure and conductivity distribution. Optimal configuration for divided electrodes is examined in terms of dividing pattern.

IEEE Transactions on Biomedical Engineering


高速フーリエ解析を用いた圧波形解析によるフィルタの目詰まり評価

高速フーリエ解析を用いた圧波形解析によるフィルタの目詰まり評価


Expression of Gap-magnetic force Characteristics of Magnetic Attachments

磁性アタッチメントのギャップ吸引力特性の表現

The Journal of the Japanese Society of Magnetic Applications in Dentistry


A Model for Long-Latency Duration-Selective Neurons in the Auditory Cortex


Accuracy of single dipole source localization by BP neural networks from 18-channel EEGs

A problem of estimating biopotential sources in the brain based on EEG signals observed on the scalp is known as an important inverse problem of electrophysiology. Usually there is no closed-form solution for this problem and it requires iterative techniques such as the Levenberg-Marquardt algorithm. Considering the nonlinear properties of inverse problem, and signal to noise ratio inherent in EEG signals, a back propagation neural network has been recently proposed as a solution. In this paper, we investigated the properties of neural networks and its localization accuracy for single dipole source localization. Based on the results of extensive studies, we concluded the neural networks are highly feasible in single-source localization with a small number of electrodes (18 electrodes), also examined the usefulness of this method for clinical application with a case of epilepsy.


Oscillatory modes in a neuronal network model with transmission latency


Active control of one dimensional sound fields in a duct by means of directional sound source and microphone

指向性を持つ音源・マイクロホンによるダクト内1次元音場の能動制御について

ダクト内を伝搬する騒音の能動制御において, 音源とマイクロホンの指向性と, 制御により生じる音場との関連について解析を行った．その結果,指向性を持つ音源とマイクロホンを用いたシステムは,騒音成分のみを検出・消去するため,両端面での反射があるケースにおいても安定した能動消音ができ, ダクト内の1次元音場は,付加音源騒音源間でのみ入力騒音の伝搬する進行波音場となることが分かった．一方,音源あるいはマイクロホンが無指向性の場合, その配置と入力騒音の周波数によってダクト内には定在波が生じ, 完全な消音はできない．以上の結果はFiltered-X LMS適応制御システムによる制御実験によって確認された．

The Journal of the Acoustical Society of Japan


System Identification for Financial Time Series Using BP Neural Networks


Measurement system of jaw movements by using BP neural networks method and a nonlinear least-squares method

The jaw movements can be measured by estimating the position and orientation of two small permanent magnets attached on the upper and lower jaws. It is a difficult problem to estimate the positions and orientations of the magnets from magnetic field because it is a typical inverse problem. The back propagation neural networks (BPNN) are applicable to solve this problem in short processing time. But its precision is not enough to apply to practical measurement. In the other hand, precise estimation is possible by using the nonlinear least-square (NLS) method. However, it takes long processing time for iterative calculation, and the solutions may be trapped in the local minima. In this paper, we propose a precise and fast measurement system which makes use of the estimation algorithm combining BPNN with NLS method. In this method, the BPNN performs an approximate estimation of magnet parameters in short processing time, and its result is used as the initial value of iterative calculation of NLS method. The cost function is solved by Gauss-Newton iteration algorithm. Precision, processing time and noise immunity were examined by computer simulations. These results shows the proposed system has satisfactory ability to be applied to practical measurement.

2個の小型磁石を上下顎に取り付け，周辺の磁界分布から顎運動を推定するのは困難である．本研究では非線形最小二乗法とニューラルネットワークを組み合わせることで，高精度，高速な測定が可能なシステムを提案し，計算機シミュレーションにより推定制度について検討している．


A New Method for Non-Invasive Measurement of Multi-layer Tissue Conductivity and Structure Using Divided Electrodes


A Split Pole Type of Magnetic Attachment with Slantly Magnetized Magnets and its Characteristics

斜めに磁化されたスプリットポール型磁性アタッチメントの特性解析


Effects of Time-Varying Strong Magnetic Fields on Rerease of Cytosolic Free Ca2+ from Intracellular Stores in Cultured Bovine Adrenal Chromaffin Cells

This study was made to explain the mechanisms for the effects of exposure to a time varying 1.51 T magnetic field on the intracellular Ca(2+) signaling pathway. The exposure inhibited an increase in intracellular Ca(2+) concentration ([Ca(2+)](i)) in bovine chromaffin cells induced by addition of bradykinin (BK) to a Ca(2+) free medium. The exposure did not change BK induced production of inositol 1,4,5-trisphosphate (IP(3)). [Ca(2+)](i) was markedly increased in IP(3) loaded cells, and this increase was inhibited by the magnetic field exposure. A similar increase in [Ca(2+)](i) by other drugs, which stimulated Ca(2+) release from intracellular Ca(2+) stores, was again inhibited by the same exposure. However, transmembrane Ca(2+) fluxes caused in the presence of thapsigargin were not inhibited by the magnetic field exposure in a Ca(2+) containing medium. Inhibition of the BK induced increase in [Ca(2+)](i) by the exposure for 30 min was mostly recovered 1 h after exposure ended. Our results reveal that the magnetic field exposure inhibits Ca(2+) release from intracellular Ca(2+) stores, but that BK bindings to BK receptors of the cell membrane and intracellular inositol IP(3) production are not influenced.


Effects of Nonuniform Acoustic Fields in Vessels and Blood Velocity Profiles on Doppler Power Spectrum and Mean Blood Velocity

This paper presents a detailed simulation method to estimate Doppler power spectrum and mean blood velocity using real CW Doppler transducers with twin-crystal arrangement. The method is based on dividing the sample volume into small cells and using the statistics of the Doppler power spectrum with the same Doppler shift frequency, which predicts the mean blood velocity. The acoustic fields of semicircular transducers across blood vessels were calculated and the effects of acoustical and physiological factors on Doppler power spectrum and mean blood velocity were analyzed. Results show that nonuniformity of the acoustic field of the ultrasonic beam in the blood vessel and blood velocity profiles significantly affect Doppler power spectrum and mean blood velocity. However, Doppler angle, vessel depth, and sample volume length are not sensitive functions. Comparisons between simulation and experimental results illustrated a good agreement for parabolic flow profile. These results will contribute to a better understanding of Doppler power spectrum and mean blood velocity in medical ultrasound diagnostics.

IEICE Transactions on Information and Systems


Phase-locked oscillations in a neuronal network model


Estimation of Multi-Layer Tissue Conductivities from Non-invasively Measured Bioresistances Using Divided Electrodes

To estimate inner multi-layer tissue conductivity distribution in a cross section of the local tissue by using bioresistance data measured noninvasively on the surface of the tissue, a measurement method using divided electrodes is proposed, where a current electrode is divided into several parts. The method is evaluated by computer simulations using a three-dimension (3D) model and two two-dimension (2D) models. In this paper, conductivity distributions of the simplified (2D) model are analyzed based on a combination of a finite difference method (FDM) and a steepest descent method (SDM). Simulation results show that conductivity values for skin, fat and muscle layers can be estimated with an error less than 0.1%. Even though different strength random noise is added to measured resistance values, the conductivities are estimated with reasonable precise, e.g., the average error is about 4.25% for 10% noise. The configuration of the divided electrodes are examined in terms of dividing pattern and the size of surrounding guard electrodes to confine and control the input currents from the divided electrodes within a cross sectional area in the tissue.


人工呼吸器の保守管理におけるIT化

人工呼吸器の保守管理におけるIT化


Integrated EEG monitoring system of brain functions during operations

In some cases, it is necessary to occlude the blood flow in a part of the brain during the surgical procedure. In such cases, it is very important to monitor brain functions, and to do appropriate treatment in order to minimize the postoperative complication. At present, several kinds of equipment specialized to monitor single modality are being used simultaneously. The aim of this study was to develop an EEG monitoring system which integrates various analyzing methods. It can indicate not only single modality information but also multi modality. In addition, the system has great advantages. It can provide complex diagnostic information by synthesizing the results of the multi modality analysis. The system consists of data acquisition, waveform memory management, and data analysis parts. To add a new analyzing method, a corresponding module was added in this part. This system can be used without difficulty because it is composed of simple modules. The first experimental system with the above architecture was made.

本研究では様々解析手法を統合することができるEEGモニタリングシステムの開発を目的としている．様々なモダリティを表示することができ，その診断結果を提示することが可能となる．本システムはデータ取得モジュール，波形メモリモジュール，データ解析モジュールから成り立っており，モジュール構造のため機能の追加が容易である．このようなアーキテクチャを持つ試作機を製作した．


BP neural networks approach for identifying biological signal source in circadian data fluctuations

Almost all land animals coordinate their behavior with circadian rhythms, matching their functions to the daily cycles of lightness and darkness that result from the rotation of the earth corresponding to 24 hours. Through external stimuli, such as dairy life activities or other sources from our environment may influence the internal rhythmicity of sleep and waking properties. However, the rhythms are regulated to keep their activity constant by homeostasis while fluctuating by incessant influences of external forces. A modeling study has been developed to identify homeostatic dynamics properties underlying a circadian rhythm activity of Sleep and Wake data measured from normal subjects, using an MA (Moving Average) model associated with Backpropagation (BP) algorithm. As results, we found that the neural network can capture the regularity and irregularity components included in the data. The order of MA neural network model depends on subjects behavior, the first two orders are usually dominant in the case of no strong external forces. The adaptive dynamic changes are evaluated by the change of weight vectors, a kind of internal representation of the trained network. The dynamic is kept in a steady state for more than 20 days at most. Identified properties reflect the subject's behavior, and hence may be useful for medical diagnoses of disorders related to circadian rhythms.

移動平均型BPニューラルネットワーク(MA-BPNN)を用いて生体の恒常性の動態を明らかにすることを試みている．健常者の覚醒-睡眠リズムを記録したところ，外的要因によって撹乱を受けても恒常性により安定化する性質があることがわかった．MABPNNは信号に含まれる規則性を獲得することができる．MABPNNの次数は被験者によって変わる．適応的に変化している恒常性の動態を，MABPNNの結合荷重を変化により評価した．動態はほとんどの場合10から20日間定常状態が保たれていた．


Cylinder Typed Magnetic Attachment with an Unidirectionally Magnetized Magnet and its Characteristics

1方向磁化シリンダ型磁性アタッチメントとその特性

The Journal of the Japanese Society of Magnetic Applications in Dentistry


Magnetic measurement system for mandibular movement

磁界を用いた下顎運動の計測システム

Magnetic measurement system using a method combining BPNN (back propagation neural networks) with NLS (nonlinear least-squares) is described in this paper. The mandibular movements can be measured by estimating the position and orientation of two small permanent magnets attached on the maxilla and mandible separately. Although a BPNN method can solve this typical inverse problem fast enough for real time measurement, the accuracy may be not local minima of an error function or be not converged. The authors propose a method combining BPNN with NLS. The new methods shows how to estimate an approximate solution of the inverse problem by the BPNN method, and how to select the initial value of the NLS method due to the results of BPNN to obtain the optimum solution, where the problem is solved by Gauss-Newton iteration algorithm. This system is proven to be accurate and fast enough for the application to diagnosis by a simulation for the practical mandibular movements.

下顎運動計測を目的とし，下顎および上顎にそれぞれ装着された2個の磁石の磁界分布から，その位置と方向を誤差逆伝播ニューラルネットワーク(BPNN)と非線形最小2乗(NLS)法を組み合わせて測定する磁気計測システムを提案した．本計測は逆問題の一種であるが，BPNNの高速性，NLS法の高精度性を利用し実用的な精度を実現することができることを計算機シミュレーションにより示した．


Event related Potentials in a patient with word meaning aphasia with special referencce to topography --- とくにそのトポグラフィーについて

語義失語症例の事象関連電位 --- とくにそのトポグラフィーについて

外傷による語義失語と正常対照群および典型失語群の漢字，仮名課題における事象関連電位(ERP)とそのトポグラフィーを比較検討した．語義失語例では漢字·かなともにコントロール群，典型失語群に比べP200が高振幅であったが，P300は不明瞭であった．P200振幅は受症36ヶ月では漢字課題において，課題正答率の増大とともに減衰した．またトポグラフィーでこのP200は左右頭頂後頭部に特異的な分布を示した．


A neural network model for quadruped gait generation and transitions


強化学習によるロボットハンドの把握制御

強化学習によるロボットハンドの把握制御

The Transactions of The Institute of Electrical Engineers of Japan


Identification of biological signal sources for circadian and cardiac cycle rhythms using BP neural networks

Biological oscillatory activity in neural networks has been intensively studied over the past years. Neuronal oscillations are the basis of many different behavioral patterns and sensory mechanism. Understanding the dynamic properties of these mechanisms is useful for analyses of biological functions and medical diagnoses. The dynamic characteristics of wake sleep circadian rhythms and ECG's cardiac cycle data measured for normal subjects are identified here, using MA BP neural network model. It was found that dynamics of regular components can be captured by the model. The captured dynamics are kept in a steady state for some periods. The order of the MA neural network was suppressively controlled by the first 2∼3 orders. Hence it may be useful for medical diagnoses of circadian rhythms and heart related diseases.


Synchronization with a periodic pulse train in an asymmetrically coupled neuronal network model


Effects on Rb+(K+) Uptake of HeLa Cells in a High K+ Medium of Exposure to a Switched 1.7 Tesla Magnetic Field

Effects of a switched, time-varying 1.7 T magnetic field on Rb(+)(K+) uptake by HeLa S3 cells incubated in an isosmotic high K(+) medium were examined. The magnetic flux density was varied intermittently from 0.07-1.7 T at an interval of 3 s. K(+) uptake was activated by replacement of normal medium by high K(+) medium. A membrane-permeable Ca(2+) chelating agent (BAPTA-AM) and Ca(2+)-dependent K(+) channel inhibitors (quinine, charibdotoxin, and iberiotoxin) were found to reduce the Rb(+)(K+) uptake by about 30-40%. Uptake of K(+) that is sensitive to these drugs is possibly mediated by Ca(2+)-dependent K(+) channels. The intermittent magnetic field partly suppress ed the drug-sensitive K(+) uptake by about 30-40% (P < 0.05). To test the mechanism of inhibition by the magnetic fields, intracellular Ca(2+) concentration ([Ca(2+)]c) was measured using Fura 2-AM. When cells were placed in the high K(+) medium, [Ca(2+)]c increased to about 1.4 times the original level, but exposure to the magnetic fields completely suppressed the increase (P < 0.01). Addition of a Ca(2+) ionophore (ionomycin) to the high K(+) medium increased [Ca(2+)]c to the level of control cells, regardless of exposure to the magnetic field. But the inhibition of K(+) uptake by the magnetic fields was not restored by addition of ionomycin. Based on our previous results on magnetic field-induced changes in properties of the cell membrane, these results indicate that exposure to the magnetic fields partly suppresses K(+) influx, which may be mediated by Ca(2+)-dependent K(+) channels. The suppress ion of K(+) fluxes could relate to a change in electric properties of cell surface and an inhibition of Ca(2+) influx mediated by Ca(2+) channels of either the cell plasma membrane or the inner vesicular membrane of intracellular Ca(2+) stores.


Identification of homeostatic dynamics for a circadian signal source using BP neural networks

System identification of biological signal sources is useful for analyses of biological functions and medical diagnoses. Homeostatic dynamics of circadian rhythms are identified here by using an MA model composed of BP neural networks. Wake-sleep rhythms measured for normal subjects are supplied for the identification. The rhythms are regulated to keep their activity constant by homeostasis, while fluctuating by incessant influences of external forces. The neural networks can acquire the regularity included in the data. The order of the MA neural network model depends on subjects, but the first three orders are dominant, usually in the case of no strong external force. The adaptive change of the homeostatic dynamics can be evaluated by the change of weight vectors, a kind of internal representation of the trained network. The dynamics are kept in a steady state for ten to 20 days at most. Identified properties reflect each subject, and hence may be useful for medical diagnoses of disorders related to circadian rhythms.

生体信号からのシステム同定は整体システムの解析や診断に有用である．本稿では移動平均型BPニューラルネットワーク(MA-BPNN)を用いて生体の恒常性の動態を明らかにすることを試みている．健常者の覚醒-睡眠リズムを記録したところ，外的要因によって撹乱を受けても恒常性により安定化する性質があることがわかった．MABPNNは信号に含まれる規則性を獲得することができる．MABPNNの次数は被験者によって変わるが，直前3点の入力が支配的である．適応的に変化している恒常性の動態を，MABPNNの結合荷重を変化により評価した．動態はほとんどの場合10から20日間定常状態が保たれていた．今回秋赤にされた特徴はそれぞれの被験者を表すものであり，概日リズムに関連する疾患の医学的診断に有用であると期待される．

ITBM-RBM (Innovation and Technology in Biology and Medicine)


Noninvasive Measurement of the Electrical Bioimpedance of Breast Tumors

The purpose of this study was to evaluate the possibility of differential diagnosis of tumors, such as breast cancer, by measuring the mammary electrical bioimpedance via the skin surface noninvasively and by examining the relationship between the tissue structure of the breast and electrical bioimpedance. The mammary electrical bioimpedance was measured in 24 patients with breast cancer. Taking into account the measurement results and the distribution of the mammary glands and fatty tissue, a breast model with tumors was proposed. Based on this model, the distributions of the electric potential and electric field in the tissue were theoretically analyzed by the three-dimensional finite element method. In clinical cases, the Re values of the diseased breast were significantly larger than those of the contralateral healthy breast. In theoretical analysis based on the breast model, the Re value of mammary electrical bioimpedance varied due to the structure of the breast, that is, the ratio of fatty tissue to mammary gland and the presence of mammary tumors. The results of the measurement agreed with the theoretical analyses. These results suggest that differential diagnosis of breast tumors is possible by measuring the mammary electrical bioimpedance using noninvasive electrodes on the skin.


A New Arrangement Method of Metal Particles by Synchronous Scanning Laser Beams

複数のレーザ光の同期走査による金属微粒子の配置法

Transactions of the Society of Instrument and Control Engineers


生体組織インピーダンスの集中定数等価回路とパラメータ推定

生体組織インピーダンスの集中定数等価回路とパラメータ推定

The Transactions of the Institute of Electronics, Information and Communication Engineers D

電子情報通信学会論文誌(D)


A coupled neural oscillator model for recruitment and annihilation of the degrees of freedom of oscillatory movements


Subcutaneous Tissue Diagnosis through Estimation of Structure by Bioimpedance and Its Equivalent Circuits

Electricity and Magnetism in Biology and Medicine


Effects of Time-Varying Strong Magnetic Field on K+ Uptake through Ca2+-Dependant K+ Channel


Effects of ELF Magnetic Fields on Collagen Synthesis in Osteoblasts


Analyses of Magnetic Retention Characteristics for Cylinder Types of Magnetic Attachment

シリンダ型磁性アタッチメントの維持力の特性解析

The Journal of the Japanese Society of Magnetic Applications in Dentistry


ELF磁界による歯根膜誘導電流の解析 歯槽骨再生の基礎

ELF磁界による歯根膜誘導電流の解析 歯槽骨再生の基礎


副賢髓質クロマフイン細胞のアセチルコリンによる細胞内カルシウムイオン増加に及ぼす変動強磁界の影響


Effects of a Time-varying Strong Magnetic Field on Transient Increase in Cytosolic Free Ca2+ Induced by Bradykinin in Cultured Bovine Adrenal Chromaffin Cells

We tested the effects of exposure to a time-varying magnetic field changing between 0.07 and 1.7 T at an interval of 3 s on transient increase in intracellular Ca2+ stimulated by bradykinin in bovine adrenal chromaffin cells. Addition of bradykinin induced the increase in intracellular Ca2+ within a few minutes. The exposure to the magnetic field perfectly suppressed the increase in intracellular Ca2+ in Ca2+-free medium. The inhibition occurred for 15 min when the maximum magnetic flux density was more than 1.4 T. These results suggest that the exposure inhibits Ca2+ release from intracellular Ca2+ stores.


Entrainment of a reciprocal inhibition neural network model to a periodic pulse train

Computational Neuroscience: Trends in Research


Effects of time-varying magnetic fields on Ca2+ concentration in chromaffin cell

変動強磁界が副腎髄質細胞の細胞内Ca2+に及ぼす影響

The Journal of Japan Biomagnetism and Bioelectromagnetics Society


Accuracy of neural network localization based on 18 electrodes EEG in a 10-20 system


A Split Pole Type of Magnetic Attachment and its Characteristics

スプリットポール型磁性アタッチメントとその特性


ニューラルネットワークを用いた磁気下顎運動計測システムに関する研究

ニューラルネットワークを用いた磁気下顎運動計測システムに関する研究

小型磁石と磁気センサを用いた下顎運動計測にバックプロパゲーション型ニューラルネットワークを適用したシステムを提案し，最適なネットワーク構造や測定精度や特性について検討した．提案法は従来の小型磁石を用いた手法とは異なり，位置と向きの実時間同時計測が可能であり，計算機シミュレーションによると位置·方向測定精度は非常に高ことから本手法は実用上非常に有用であると考えられる．


Fast in vivo measurements of local tissue impedances using needle electrodes

The objective of the research is to show an in vivo, fast method of measurement of local tissue bio-impedance in the beta dispersion region (0-200 kHz). A needle electrode is used for the purpose. The performances with respect to circuits, electrodes, measurement area and electrical representations are evaluated. A measurement example is shown, and the electrical representations are discussed and compared using it. The method discussed, although invasive, is considered to be useful for local tissue diagnoses concerning structures and physiological functions.

Medical and Biological Engineering and Computing


Equivalent Distributed Circuits for Bioimpedance of Nonuniform Tissue and their Characteristics

組織の非一様性を考慮した生体インピーダンスの等価分布回路とその特性

ベータ分散領域における生体インピーダンスは組織生理機能に関する有用な情報を提供する. ところで実際の組織は, 機能的に同一の組織であっても, 細胞の密度, 形状, 大きさ, 位置などの変動による空間的な非一様性が存在する. 通常この非一様性はCole-Cole則で代表されるように, 緩和時間の確率分布で取り扱われるが, その結果は必ずしも実測インピーダンスと一致しない. ここでは細胞外液および内液抵抗, 形質膜容量を要素とする回路からなる空間分布回路を用いた. これらの要素がガンマ分布に従うものとして等価インピーダンスを計算し, その周波数軌跡の形状を求めた. その結果, インピーダンス軌跡は回路構造にさほど依存せず, 要素の平均値, 分散のような統計量によって支配され, 1次元並列回路の特性で代表されることがわかった. この結果を測定データに適用したところ, 振幅特性, 位相特性とも実測値とよく一致することがわかった. 従って, 本等価回路はベータ分散領域における組織の等価電気特性を表現するのに有用であると思われる. また実測データから推定される統計量は組織の非一様性の定量的評価に利用できるものと考えられる.

The Transactions of the Institute of Electronics, Information and Communication Engineers D-II

電子情報通信学会論文誌(D-II)


Entrainment of a spiking neuron model to two periodic pulse trains

Computational Neuroscience, Trends in Research


Temporal Integration and Duration Tuning in the Dorsal Zone of Cat Auditory Cortex

The present study examined auditory cortical neurons, the responses of which depended on the duration of noise bursts. We recorded from 150 neurons with response latencies exceeding 30 msec and from 28 neurons with OFF responses to auditory stimuli in the dorsal zone of cat auditory cortex. Of 150 long-latency neurons, 132 displayed some form of duration selectivity. Seventy-eight were classified as selective for long durations. Among the long-duration-selective neurons, 30 responded only to noise burst stimuli with durations longer than a minimal threshold and were classified further as duration threshold neurons. Of 132 duration-selective neurons, 41 responded selectively to noise bursts of short duration; 13 showed maximal responses to noise bursts of a particular duration and could be regarded as duration-tuned neurons. OFF-response neurons included ones that were long-duration-selective, duration-tuned, and nonduration-selective. Duration tuning has been described previously only at the midbrain level in amphibians and bats. The present finding of sensitivity to sound duration in at least one region of cat auditory cortex indicates that this form of neural tuning may be important for hearing in all vertebrates, and for processing of sound at multiple levels in the auditory pathway. The duration tuning in the cat auditory cortex was much broader, and the best duration was distributed over a wider range than in the bat inferior colliculus. We suggest that the duration selectivity of the long-latency neurons results from integration along the time domain of a stimulus during the latent period.


変動強磁界が及ぼす細胞膜1価イオン輸送への影響

変動強磁界が及ぼす細胞膜1価イオン輸送への影響


Circuit and packet integrated switching architecture for an optical loop network


Blood flow of the carotid artery during breath-holding in relation to diving bradycardia

The present study investigated the mechanism of diving bradycardia. A group of 14 healthy untrained male subjects were examined during breath-holding either out of the water (30-33 degrees C), in heat-out immersion, or in whole-body submersion (27-29 degrees C) in a diving pool. Blood velocity, blood volume flow in the carotid artery, diastolic blood pressure and electrocardiogram were measured and recorded during the experiments. The peak blood velocity increased by 13.6% (P < 0.01) and R-wave amplitude increased by 57.1% (P < 0.005) when the subjects entered water from air. End-diastolic blood velocity (Ved) in the carotid artery increased significantly during breath-holding, e.g. Ved increased from 0.20 (SD 0.02) m.s-1 at rest to 0.33 (SD 0.04) m.s-1 (P < 0.001) at 50.0 s in breath-hold submersion to a 2.0-m depth. Blood volume flow in the carotid artery increased by 26.6% (P < 0.05) at 30 s and 36.6% (P < 0.001) at 40 s in breath-hold submersion to a 2.0-m depth. Diastolic blood pressure increased by 15.4% (P < 0.01) at 60 s during breath-holding in head-out immersion. Blood volume flow, Ved and diastolic blood pressure increased significantly more and faster during breath-holding in submersion than out of the water. There was a good negative correlation with the heart rate: the root mean square correlation coefficient r was 0.73 (P < 0.001). It was concluded that an increased accumulation of blood in the aorta and arteries at end-diastole and decreased venous return, caused by an increase in systemic peripheral resistance during breath-holding, underlies diving bradycardia.

European Journal of Applied Physiology and Occupational Physiology


Influences on Attractive Force in Different Clinical Uses of A Cup Yoke Magnetic Attachment

臨床的使用条件がカップヨーク型磁性アタッチメントの吸引力に及ぼす影響

The Journal of the Japanese Society of Magnetic Applications in Dentistry


ELF領域の正弦波交流磁界が骨芽細胞に及ぼす影響

ELF領域の正弦波交流磁界が骨芽細胞に及ぼす影響

第11回日本生体磁気学会大会

第11回日本生体磁気学会大会


Dipole source localization of MEG by BP neural networks

The purpose of this study was to examine the usefulness of BP neural network for source localization of MEG. Since the performance of this method does not depend on the complexity of brain parameters and source models, a homogeneous brain model and a single current dipole source are assumed for convenience. Localization accuracy was examined in relation to the configuration and scale of the network. As a result, average error for position and moment estimations was within 2% while the maximum error was about 5%. It was therefore concluded that the neural network method, was useful for MEG source localization, though some improvements are still necessary.


Control of oscillation in a plastic neural oscillator


Detection of Pulse Timing and Amplitude from PPM-PAM Multiplexed Pulse by Using Linear Filter

線形フィルタを用いたPPM-PAM多重変調パルスの検出

PPM-PAM変調はパルスのタイミングと振幅を独立に変化させることができる方式であるが，このタイミングと振幅を分離する受信フィルタの特性を検討した．準最適フィルタを用いてパルス干渉の低減とエラー特性を得ることができ，PPM-PAM多重伝送が実現可能であることを明らかにした．

The Transactions of the Institute of Electronics, Information and Communication Engineers A

電子情報通信学会論文誌(A)


Spatial Profile of Blood Velocity Reconstructed from Telemetered Sonogram in Exercising Man

IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences


An experimental study of conductive heating using a concentric double-electrode applicator


Electrical properties of extracted rat liver tissue


Exercise-induced Changes in R Wave Amplitude and Heart Rate in Normal Subjects

An intermittent exercise protocol on a treadmill was used to examine six healthy subjects, and a steady protocol was applied to three of the subjects before and after short-term training. The peak blood velocity in the common carotid artery increased by 73.1% during the intermittent protocol and recovered to resting level within 3 minutes, while the heart rate (HR) remained high even 5 minutes after exercise. R wave amplitude (RWA) increased significantly from 1.40 +/- 0.39 mV at rest to 1.59 +/- 0.33 mV (P < .05) immediately after the start of walking, and decreased gradually to 1.46 +/- 0.36 mV (P < .05) during 3 minutes of walking. Thus, it decreased significantly to 1.31 +/- 0.40 mV (P < .01) during the interphase from exercise to rest, and increased again during recovery or rest periods in the intermittent protocol. The results suggest that an increase in the venous return per heart beat at the start of walking induces the increase in RWA, and that its abrupt decrease at the end of walking induces the decrease in RWA. Subjects with a higher HR response and recovery slopes have smaller abrupt changes in RWA at the interphases between rest and walking. The gradual decrease in RWA during walking may be related to a gradual increase in HR and a gradual decrease in systemic peripheral resistance, and the gradual increase in RWA after walking may be related to a gradual decrease in HR and a gradual increase in systemic peripheral resistance.


Filter Optimization for Pulse Timing Detector

パルスタイミング検出における線形フィルタの最適化

PPMのパルスタイミングフィルタはいくつか発表されているが，改善の程度が明らかでない．タイミングエラーの2乗平均の観点から比較し，有効性や実現の容易性の点等を相対的に比較している．

電子情報通信学会論文誌(A)


Blood flow velocity in the commom carotid artery in humans during graded exercise on a treadmill


Basic studies on the application of neural networks for measurement of jaw movements using a magnetic sensor system

磁気センサを用いた顎運動計測へのニューラルネットワークの応用に関する基礎的研究

顎運動は顎関節症の診断や咬合機能等について重要な情報を含んでいるといわれ，古くから様々な方法により検討が行われてきた．しかし高精度，高時間分解能，多自由度同時計測，取扱容易という条件を満たす理想的な計測システムはほとんどない．ここでは小型磁石と磁気センサを用いた計測システムについて，従来の繰り返し計算を用いるのではなくバックプロパゲーションニューラルネットワークを用いたシステムを提案し，顎運動計測システムへの適用可能性について，計算機シミュレーションを用いた基礎的検討を行った．その結果，提案法が有用であることが示された．

The Journal of the Japanese Society of Magnetic Applications in Dentistry


Application of electrical impedance analysis for diagnosis of a pulmonary mass


A study of the electrical bioimpedance of tumors

A new system of impedance measurement over a frequency range of 0 to 200 kHz was developed by a three-electrode method. In this study, the electrical impedances of various tumors were measured in vivo in 54 patients with breast disease (31 breast cancers, 13 fibroadenomas, and 10 fibrocystic diseases) and 57 patients with pulmonary disease (44 lung cancers, 5 metastatic pulmonary tumors, 4 pulmonary tuberculoses, and 4 organized pneumonias). On the basis of those impedance measurements and the equivalent circuits in vivo, we calculated the extracellular resistance (Re), intracellular fluid resistance (Ri), and cell membrane capacitance (Cm) in tissues, all of which were compared among the various diseases. It was found that Re and Ri were significantly higher in breast cancers than in benign tumors and normal breast tissues and that Cm was significantly lower in breast cancers than in other tissues. On the other hand, Re and Ri were significantly higher, and Cm was significantly lower, in normal lung tissues than in pulmonary masses. Re and Ri were significantly higher, and Cm was significantly lower, in malignant tumors than in organized pneumonias. The results showed that these parameters (Re, Ri, and Cm) exhibit significant differences among various tissues and tumors, suggesting possible applications in tumor diagnosis.


Changes in caritid blood flow and electrocardiogram in humans during and after walking on a treadmill

Blood flow velocity in the common carotid artery and the electrocardiogram were measured simultaneously by telemetry in seven male subjects during 20-min walking on a treadmill at an exercise intensity corresponding to a mean oxygen uptake of 26.0 (SD 2.9) ml.kg-1.min-1. The mean cardiac cycle was shortened from 0.814 (SD 0.103) s to 0.452 (SD 0.054) s during this exercise. Of this shortening, 73% was due to shortening of the diastolic period and 27% to shortening of the systolic period. In the relatively small shortening of the mean systolic period [from 0.377 (SD 0.043) s to 0.268 (SD 0.029) s], the isovolumetric contraction time was shortened by 56%. During exercise, the heart rate (fc) increased by 79.4% [from 74.3 (SD 9.3) beats.min-1 to 133.3 (SD 14.8) beats.min-1], and the peak blood velocity (S1) in the common carotid artery increased by 56.1% [from 0.82 (SD 0.10) m.s-1 to 1.28 (SD 0.11) m.s-1]. After exercise, the S1 decreased rapidly to the resting level. The fc decreased more slowly, still being higher than the initial resting level 5 min after exercise. The diastolic velocity wave and the end-diastolic foot decreased during exercise. The blood flow rate in the carotid artery increased transiently by 13.5% at the beginning of exercise [from 5.62 (SD 0.63) ml.s-1 to 6.38 (SD 0.85) ml.s-1] and by 26.5% at the end of the exercise period [from 5.62 (SD 0.63) ml.s-1 to 7.11 (SD 1.34) ml.s-1].(ABSTRACT TRUNCATED AT 250 WORDS)

European Journal of Applied Physiology and Occupational Physiology


TELEMETERING BLOOD FLOW VELOCITY AND ECG DURING EXERCISE

Innovation and Technology in Biology and Medicine


Effects of time-varying electro magnetic fields on K+(Rb+) fluxes and surface charge of HeLa cells


The Optimum Linear Filter of PPM Receiver

PPM伝送系における線形最適フィルタ

相加性雑音と信号依存性雑音の存在するPPM伝送系における受信側線形最適フィルタを扱ったもので，パルスの位置検出においてタイミングエラーの2乗を最小にするものである．PPM伝送系の最適フィルタがPAM伝送系の最適フィルタと微分器によって構成されることを明らかにした．

The Transactions of the Institute of Electronics, Information and Communication Engineers A

電子情報通信学会論文誌(A)


Effects of Static Magnetic Fields on Diffusion in Solutions


New CPFSK by Minimum Time Control Theory

最短時間応答法を用いた新しい位相連続FSK

データが一つ前のタイムスロットと異なるとき大きな周波数偏移の波形を送り，復調回路を速やかに応答させ，同じなら応答済みの出力を維持するのに必要な小さな周波数偏移を伝送する．これにより符号間干渉を起こさず，復調回路の遮断周波数を低くできるのでビット誤り率が改善されることを示した．

The Transactions of the Institute of Electronics, Information and Communication Engineers B

電子情報通信学会論文誌(B)


A Technique for Constructing Magnetic Attachments


Quick-Response Phase-Shifter Using Digital Phase-Locked Loops

ディジタルPLLを用いた速応移相器

パルス周波数伝送系の積分器を用いたPLLを要素として移相器を構成したものである．移相器はVCOのノコギリ波形をレベルスライスするもので，周波数が変化しても移相量は変化しない．また応答は設定移相量に対し1周期以内の時間で，また周波数の変化に対しても同様の短い時間で整定する．

電子情報通信学会論文誌(A)


Optimization and Design of Permanent Magnet Devices for Retaining Dental Prosthetic Appliances

IEEE Transactions on Biomedical Engineering


Linear digital phase-locked loops using integrators in a pulse frequency-modulation system

パルス周波数伝送系の積分器を用いた1次および2次ディジタルPLLの構成法を述べたもので，定式化も動作原理が分かりやすくなるように行い，さらに量子化が目立つような高い入力周波数でも動作できることを示した．

IEE Proceedings F, Communications, Radar and Signal Processing


Detection of Digital FSK Employing the First-Order Digital PLL Composed of the Integrator

積分器を持つ1次ディジタルPLLを用いたFSK復調

積分器を持つ1次ディジタルPLLを用いてFSK復調を行ったときの，ビット誤り率を求めている．確率密度関数はS.O.Riceの理論から導出したもので，実験結果とも良く一致している．

電子情報通信学会論文誌(B)


Time-Optimal Digital Phase-Locked Loop Using Integrators in Pulse Frequency Modulation System

最短時間ディジタルPLL

パルス周波数伝送系の積分器を用いて,入力の1周期で整定する最短の1次及び2次ディジタルPLLの構成方法を示した．周波数ステップ，位相ステップ及び周波数ランプ入力にも追随することができることを示した．

電子情報通信学会論文誌(B)


High-Order Digital Phase-Locked Loop Using Integrators in Pulse Frequency Modulation System

パルス周波数伝送系の積分器を用いた高次ディジタルPLL

パルス周波数伝送系の積分器を用いて，事実上同期範囲の制限のないディジタル方式の5種類の2次PLLを実現している．従来のアナログPLLとの比較も行っている．さらにアナログの3次PLLの欠点であった不安定な動作が無くなった3次のディジタルPLLの構成方法も示した．

電子情報通信学会論文誌(B)


First-Order Digital Phase-Locked Loop Using Integrator in Pulse Frequency Modulation System

パルス周波数伝送系の積分器を用いた1次ディジタルPLL

パルス周波数伝送系の積分器を用いて，事実上同期範囲の制限のないディジタル方式の1次PLLを実現している．動作解析の結果，一次微分方程式で表せること及び系の遮断周波数が同期範囲と独立に選べる等の特徴を明らかにした．

The Transactions of the Institute of Electronics, Information and Communication Engineers A

電子情報通信学会論文誌(A)


Sinusoidal Oscillator with Integrators in Pulse Frequency Modulation System

パルス周波数伝送系の積分器を用いた正弦波発振器

ディジタル方式のパルス周波数伝送系の積分器を提案し，これを従属に接続して正弦波発振器を構成した．解析を行い，安定なリミットサイクルが存在することおよび実験も行い安定な発振をすることをしめした．

The Transactions of the Institute of Electronics, Information and Communication Engineers C

電子情報通信学会論文誌(C)