Development of a standard evaluation method for microbial UV sensitivity using light-emitting diodes


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


Evaluation of Temperature Increase from Joule Heat in Numerical Tooth Model by Applying 500 kHz Current for Apical Periodontitis Treatment Effect of applied voltage and tooth conductivity

For apical periodontitis treatments, a new method with the insertion of an electrode into the root canal of a tooth and application of a current at 500 kHz to sterilize the area by Joule heat has attracted attention. However, few studies have quantified the temperature increase in the root canal. This study aimed to investigate the basic characteristics of the temperature increase in a simple and standard tooth model when energizing a current at 500 kHz to the numerical tooth model with typical electrical and physical properties. We developed a numerical model of a standard tooth (dentin) and periodontal tissues consisting of an alveolar bone, cortical bone, and gingiva, and physiological saline in a root canal and calculated the temperature increase inside the numerical model by a coupled analysis of current and heat when a voltage was applied across the electrodes. The calculated results for the different applied voltages showed a temperature increase at the apical portion of the root canal, which increased with the applied voltage even for the same total supplied energy. The temperature increase occurred at the apical portion of the root canal as the tooth conductivity decreased. When the tooth conductivity was high, a current passed through the dentin, which led to a decrease in the temperature at the apical portion of the root canal. However, a chemical solution with a higher conductivity in the root canal tended to increase the temperature at the apical portion of the root canal, regardless of the tooth conductivity. More efficient approaches for increasing the spatial and temporal temperature for the tooth model target are needed. © 2021 Bioelectromagnetics Society.


Bowel sound-based features to investigate the effect of coffee and soda on gastrointestinal motility

Biomedical Signal Processing and Control


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


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


Effectiveness of visible and ultraviolet light emitting diodes for inactivation of Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli: A comparative study.

Malaysian Journal of Fundamental and Applied Sciences


Adaptive resources allocation algorithm based on modified PSO for cognitive radio system.


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


Automatic Bowel Motility Evaluation Technique for Noncontact Sound Recordings


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)


Comparison of standard light-emitting diode (LED) and 385 nm ultraviolet A LED (UVA-LED) for disinfection of Escherichia coli


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


The Real-Time Monitoring System of Blood Flow Velocity Using Doppler Ultrasound for Healthcare Application

Doppler ultrasound is a widely used and reliable noninvasive device for blood flow waveform measurement. However, the commercialized blood flow devices are usually in hospital with limited access for public, required monitoring by competent staff and not easily transported. The aim of current study is to examine the potential of a portable blood flow velocity (BFV) Doppler ultrasound system for healthcare application. The effects of visceral fat (VF) level, blood pressure (BP) level (hypertension), aging, regular exercise and exercise-trained programme toward blood flow waveforms and its indices are determined. The peak systolic (S1) velocity and resistive index (RI) are significantly higher (p<0.05) in older population who exercise regularly than who does not. There are significant differences (p<0.05) in the RI and velocity reflection index between normotensive and hypertensive groups. The S1 and peak diastolic (D) are decreased significantly (p<0.05) from normotensive to hypertension groups. Low VF group has significantly increase vascular elasticity than high VF group. In contrast, low VF group has decrese reflected wave velocity. Our findings have broad implication in prevention and monitoring of cardio-related healthproblem that possibly early detection by frequent measurement of BFV, BP and electrocardiogram using this portable device.


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


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.

The Journal of Medical Investigation : JMI


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．


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．


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．


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.


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


Additional effects of silver nanoparticles on bactericidal efficiency depend on calcination temperature and dip-coating speed.

There is an increasing interest in the application of photocatalytic properties for disinfection of surfaces, air, and water. Titanium dioxide is widely used as a photocatalyst, and the addition of silver reportedly enhances its bactericidal action. However, the synergy of silver nanoparticles and TiO(2) is not well understood. The photocatalytic elimination of Bacillus atrophaeus was examined under different calcination temperatures, dip-coating speeds, and ratios of TiO(2), SiO(2), and Ag to identify optimal production conditions for the production of TiO(2)- and/or TiO(2)/Ag-coated glass for surface disinfection. Photocatalytic disinfection of pure TiO(2) or TiO(2) plus Ag nanoparticles was dependent primarily on the calcination temperature. The antibacterial activity of TiO(2) films was optimal with a high dip-coating speed and high calcination temperature (600°C). Maximal bacterial inactivation using TiO(2)/Ag-coated glass was also observed following high-speed dip coating but with a low calcination temperature (250°C). Scanning electron microscopy (SEM) showed that the Ag nanoparticles combined together at a high calcination temperature, leading to decreased antibacterial activity of TiO(2)/Ag films due to a smaller surface area of Ag nanoparticles. The presence of Ag enhanced the photocatalytic inactivation rate of TiO(2), producing a more pronounced effect with increasing levels of catalyst loading.


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


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．


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


Hfq regulates anti-oxidative ability in Vibrio parahaemolyticus.

Hfq plays a fundamental role in bacterial cell physiology. It can stimulate or repress the expression of certain target genes, and there is a possibility that Hfq regulates the oxidative stress response. However, how Hfq functions that in Vibrio parahaemolyticus remains speculative. In this paper, we explain the functions Hfq plays in V. parahaemolyticus in the gene expression of superoxide dismutase gene and catalase gene, comparing the hfq deletion mutant strain to the parental strain. The results show that the hfq deletion mutant V. parahaemolyticus has a stronger ability to resist H(2)O(2). Superoxide dismutase (SOD) and catalase (CAT) activities in the hfq deletion mutant were remarkably higher than in the parental strain. Genetic experiments indicated that the gene expression of sod and kat was up-regulated in the mutant strain. These results indicate that Hfq down-regulates CAT and SOD activity, and Hfq is associated with the oxidative stress response.

The Journal of General and Applied Microbiology


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.


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.


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


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．


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


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.


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．


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


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


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


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．


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．


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．

The Journal of the Japanese Society of Magnetic Applications in Dentistry


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．


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.


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)


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．


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．


一般照明および植物育成照明に応用できる新しいLED照明方法の開発

一般照明および植物育成照明に応用できる新しいLED照明方法の開発

LED総合フォーラム2018 in 徳島 論文集

LED総合フォーラム2018 in 徳島 論文集


Blue light-emitting diodes induce autophagy in colon cancer cells by Opsin 3.

Light emitting-diodes (LED) have various effects on living organisms and recent studies have shown the efficacy of visible light irradiation from LED for anticancer therapies. However, the mechanism of LED's effects on cancer cells remains unclear. The aim of the present study was to investigate the effects of LED on colon cancer cell lines and the role of photoreceptor Opsin 3 (Opn3) on LED irradiation in vitro. Human colon cancer cells (HT-29 or HCT-116) were seeded onto laboratory dishes and irradiated with 465-nm LED at 30 mW/cm for 30 minutes. Cell Counting Kit-8 was used to measure cell viability, and apoptosis and caspase 3/8 expression were evaluated by AnnexinV/PI and reverse transcription-polymerase chain reaction (RT-PCR), respectively. Autophagy and expression of LC-3 and beclin-1 were also evaluated by autophagy assays, RT-PCR and Western blotting. We further tested Opn3 knockdown by Opn3 siRNA and the G G-protein inhibitor NF023 in these assays. Viability of HT-29 and HCT-116 cells was lower in 465-nm LED-irradiated cultures than in control cultures. LC-3 and beclin-1 expressions were significantly higher in LED-irradiated cultures, and autophagosomes were detected in irradiated cells. The reductive effect of cancer cell viability following blue LED irradiation was reversed by Opn3 knockdown or NF023 treatment. Furthermore, increased LC-3 and beclin-1 expression that resulted from blue LED irradiation was suppressed by Opn3 knockdown or NF023 treatment. Blue LED irradiation suppressed the growth of colon cancer cells and Opn3 may play an important role as a photoreceptor.


Effect of light irradiation by light emitting diode on colon cancer cells.

Recent studies have demonstrated the efficacy of irradiation from light emitting diodes (LED) for wound healing, anti-inflammation and anticancer therapies. However, little is known about the effects of visible light in colon cancer cells. The purpose of this study was to evaluate the biological response (including gene expression changes) of human colon cancer cells to different wavelengths of LED irradiation. Human colon cancer cells (HT29 or HCT116) were seeded onto laboratory dishes that were then put on LED irradiation equipment with a 465 nm-, 525 nm-, or 635 nm-LED. Irradiation at 15 or 30 mW was performed 10 min/day, each day for 5 days. The cell counting kit8 was then used to measure cell viability. Apoptosis and expression of several mRNAs (caspase, MAPK and autophagy pathway) in HT29 cultures irradiated with 465 nm LED were evaluated via AnnexinV/PI and RT-PCR, respectively. Viability of HT29 and HCT116 cells was lower in 465 nm-LED irradiated cultures than in control cultures, but viability of HT29 cells did not differ between control cultures and 525 nm-LED or 635 nm-LED irradiated cultures. Moreover, the expression of FAS, caspase-3, capase-8, and JUK were significantly higher in 465 nm-LED irradiated cultures than in control cultures, and expression of ERK1/2 and LC3 was lower in blue-irradiated cells. LED irradiation at 465 nm inhibited the proliferation of HT29 cells and of HCT116 cells. Notably, LED irradiation at 465 nm promoted apoptosis inHT29 cultures via the extrinsic apoptosis pathway and the MAPK pathway.


Cognitive Engine Design for Cognitive Radio in LTE-Advanced Communication Frame Based on Modified Particle Swarm Optimization