著者
稲田 慎 相庭 武司 原口 亮 芦原 貴司 草野 研吾 清水 渉 池田 隆徳 中沢 一雄
出版者
公益社団法人 日本生体医工学会
雑誌
生体医工学 (ISSN:1347443X)
巻号頁・発行日
vol.54Annual, no.28AM-Abstract, pp.S264-S264, 2016 (Released:2016-11-19)

Our research group have been conducting simulation studies for analyzing arrhythmia such as sick sinus syndrome, atrial fibrillation, ventricular tachycardia and fibrillation using multi-scale heart models with personal computer and supercomputer. One purpose of our simulation studies is to stratify the arrhythmic risk non-invasively using computer simulation. Recent study has shown that conduction delay around the right ventricular outflow tract is one of the mechanisms to induce ventricular arrhythmias such as Brugada syndrome. Our findings from computer simulation suggest that our model may be useful to stratify the arrhythmic risk in the Brugada syndrome. In this symposium, we will present our simulation scheme and recent progresses. In addition, we would like to discuss our future prospect and the possibility of computer simulation.
著者
田ヶ谷 浩邦
出版者
公益社団法人 日本生体医工学会
雑誌
生体医工学 (ISSN:1347443X)
巻号頁・発行日
vol.46, no.2, pp.169-176, 2008-04-10 (Released:2008-10-06)
参考文献数
55
被引用文献数
4
著者
菊地 謙次 寺田 信幸 望月 修
出版者
公益社団法人 日本生体医工学会
雑誌
生体医工学 (ISSN:1347443X)
巻号頁・発行日
vol.46, no.2, pp.232-237, 2008-04-10 (Released:2008-10-06)
参考文献数
4
被引用文献数
1

Many researches and developments have tried to realize a μTAS in several fields, but it has not been realized yet because of a scale effect in the course of miniaturization. It is difficult to make an enough volume of flow in a micro tube. This is a bottleneck of realizing the μTAS. We have tried to apply a unique mechanism of insects to the μTAS devises. In this paper, we focused on a blood-sucking mechanism of a mosquito that can obtain blood at the rate of approximately 1.0 μl/min. To understand the structure of their pumps, we made a mosquito into many slices, and anatomized under a microscope; we also let mosquitoes feed on human blood on a glass plate. We found the following results: 1) a manner of blood sucking, 2) a power density of the pump system by an analysis of flowing red blood cells at a tip of proboscis of mosquito. We have succeeded to reveal the blood-sucking mechanism of the mosquitoes, which can be applied to micro fluid devices.
著者
田河 賢治 木下 賢吾
出版者
公益社団法人 日本生体医工学会
雑誌
生体医工学 (ISSN:1347443X)
巻号頁・発行日
vol.55Annual, no.Proc, pp.601-602, 2017-05-03 (Released:2017-09-13)
参考文献数
2

Motivation: Over the past few years, activity trackers which can measure everyday steps, energy expenditures, and sleeping time are getting popular. Especially these days, some activity trackers use not only accelerometers but also optical heart rate monitors based on photopletysmography. In this study, we evaluated reliability of an optical heart rate activity tracker during running.Method and Results: Several subjects(n=11, all male) ran 1km on a flat road and we analyzed heart rate errors to check if there was a difference between subjects. We found that some subjects had significantly higher Mean Absolute Error than others(highest MAE,20.54±13.64; average MAE, 8.41±6.47), and there was a strong correlation between each subject's MAE and the standard deviation of running speed(Pearson's r=0.87, p<0.001).Conclusion: Optical HR monitors lead to errors when users change their pace of running.
著者
降矢 典雄 大田黒 紘之 酒本 勝之
出版者
Japanese Society for Medical and Biological Engineering
雑誌
生体医工学 (ISSN:1347443X)
巻号頁・発行日
vol.52, pp.O-317-O-318, 2014

This study is aimed at investigating possibility of Impedance CT applying two-dimensional analysis. Two-dimensional Electrical Impedance CT has two advantages. This analysis method can estimate internal conductivity distribution faster and the number of required electrodes is fewer compared to three-dimensional analysis. It is suitable for using clinical application. At first, we tried to apply easy filter using the ratio of the potential distribution. However the result of the analysis had the image with noise and indicated not so correct conductivity distribution. The results depend on the relationship between conductivities and positions of the object of different conductivity and tissue around it. It was found that the problem caused by the difference of dimensions occurred. Therefore we need to apply new filter to eliminate the influence of the difference of dimensions. By using a new filter based on Neural Network, it was suggested that the correct conductivity distribution can be obtained.
著者
赤枝 建夫 浅川 徹也 多屋 優人 横山 浩之 林 拓世 水野(松本) 由子
出版者
公益社団法人 日本生体医工学会
雑誌
生体医工学 (ISSN:1347443X)
巻号頁・発行日
vol.51, no.2, pp.89-94, 2013-04-10 (Released:2013-09-10)
参考文献数
21

The objective of this research is to evaluate autonomic nervous function in Holter Electrocardiogram (ECG) using smartphone under the emotional stimuli. Twenty-four healthy subjects were assessed using State Trait Anxiety Inventory (STAI) and divided into two groups:high anxiety group and low anxiety group. ECG was measured under emotionally audio-visual stimuli (relax, pleasant, and unpleasant stimuli) and emotional sentence stimuli (pleasant sentence and un-pleasant sentence stimuli) using smartphone. The RR interval from ECG was analyzed for estimating the HF% and LF/HF values. The HF% and LF/HF values among stimuli and between groups were compared using analysis of variance (ANOVA) and t-test, respectively. The LF/HF values of pleasant, unpleasant, pleasant sentence, and unpleasant sentence stimuli were significantly higher than the value of relax stimuli. The LF/HF value of unpleasant stimuli in low anxiety group was significantly higher than the value in high anxiety group. This research suggests that the autonomic nervous function would be different based on the emotional stimuli and the presence of anxiety.
著者
Shinichi FUKUHARA Takeshi FUJINAGA Shogo WATANABE Hisao OKA
出版者
一般社団法人日本生体医工学会
雑誌
生体医工学 (ISSN:1347443X)
巻号頁・発行日
vol.54Annual, no.Proc, pp.P2-C04-1-P2-C04-2, 2016 (Released:2016-11-19)
参考文献数
3

Electromyogram (EMG) is recorded electrical muscle contraction, mechanomyogram (MMG) indicates cross-sectional area change of muscle, reflect mechanical muscle contraction. By simultaneously measuring both signals, it is possible to multifaceted evaluation of muscle contraction. However, MMG measurement at voluntary movement was difficult. Therefore, the authors developed MMG / EMG hybrid transducer capable of simultaneous measurement of MMG and EMG. This study evaluated MMG and EMG of rectus femoris (RF) and hamstrings using recumbent bicycle of easy load regulation. As result, dMMGbase (baseline of displacement MMG) indicated cross-sectional area change of muscle at pushing down and pulling up of pedal. In addition, EMG and dMMGbase increased with pushing down of pedal in RF, dMMGacc (acceleration dMMGbase) showing muscle contraction force was output simultaneously. Each signal of hamstrings had output that antagonize RF. By simultaneously measuring MMG and EMG at recumbent bicycle pedaling, it was possible to evaluate muscle contraction of voluntary movement.
著者
小橋 昌司 諸岡 孝俊 奥野 真起子 森本 雅和 吉矢 晋一 相河 聡
出版者
公益社団法人 日本生体医工学会
雑誌
生体医工学 (ISSN:1347443X)
巻号頁・発行日
vol.54Annual, no.26PM-Abstract, pp.S123-S123, 2016 (Released:2016-11-19)

Total knee Arthroscopy (TKA) is an operation which replaces the damaged knee with an artificial knee implant. There are some kinds of TKA procedures, and various kinds of prosthesis. Thus, it becomes a tough work for surgeons to select an appropriate procedure and prosthesis for individual patients. This study proposes a prediction method of post-operative implanted knee kinematics. It predicts the post-operative kinematics from only pre-operative kinematics using a machine learning method with clinical big data. In 46 TKA subjects, the method predicts the post-operative anterior-posterior translation with a correlation coefficient of 0.77 and a root-mean-squared error of 0.7mm.
著者
岡本 和也 内山 俊郎 竹村 匡正 足立 貴行 粂 直人 黒田 知宏 内山 匡 吉原 博幸
出版者
公益社団法人 日本生体医工学会
雑誌
生体医工学 (ISSN:1347443X)
巻号頁・発行日
vol.49, no.1, pp.40-47, 2011-02-10 (Released:2011-12-13)
参考文献数
30

A DPC code expresses a primary disease, a complication, and procedures, etc. In 2010, 1334 hospitals use DPC codes for calculations of medical fees. Since, in the hospitals, the medical fee of each case is calculated based on one DPC code, each case must be classified into one DPC code. However, the classification is difficult in some cases because patients sometimes have various conditions. Therefore, automatic DPC code selections using machine learning are being studied. Suzuki et al. evaluated automatic DPC code selections from discharge summaries using a vector space method. However, there are general machine learning methods except for the vector space method. Hence, we must evaluate other machine learning methods exhaustively for improvement of accuracy of automatic DPC code selections. Therefore, we evaluated automatic DPC code selections from discharge summaries using naïve Bayes method, SVM, concept base method, and another vector space method which is different from the vector space model used by Suzuki et al. We considered these machine learning methods as general ones. We also focus on characteristics of each machine learning methods on automatic DPC code selections and we utilize a method which combines some machine learning methods. First, the combining method estimates confidences of the machine learning methods bases on classification scores that the machine learning methods regard as classification evidence. Next, the combining method adopts the method whose confidence is highest. We compared accuracy of the methods using discharge summaries created in 2008 fiscal year in Kyoto University Hospital. As a result, SVM classified 72.2% of the cases into correct DPC codes though the vector space model utilized by Suzuki et al. classified 64.8% into correct DPC codes. Moreover the combining method classified 76.1% into correct DPC codes. In conclusion, we achieved significant improvement.
著者
嶋津 秀昭 瀬野 晋一郎 加藤 幸子 小林 博子 秋元 恵実
出版者
公益社団法人 日本生体医工学会
雑誌
生体医工学 (ISSN:1347443X)
巻号頁・発行日
vol.43, no.1, pp.117-123, 2005 (Released:2007-01-19)
参考文献数
14
被引用文献数
4

We have developed a method and a system to quantitatively evaluate human pain without relying on subjective criteria. The concept of pain quantification is to compare the magnitude of the subject's pain to the magnitude of a painless electric stimulus that is comparable to actual pain. We quantified degree of pain as the pain ratio, based on the ratio between pain equivalent current and minimum perceived current. In the system developed as the objective of this study, a gradually increasing pulsed current (frequency was 50 Hz, and the pulse width was 0.3 ms) was applied to the subject's medial forearms, and the subjects compared the magnitude of this sensation to electrical stimulation produced by an electrical current. Using test equipment, we conducted basic evaluations of measurement principles. We induced two types of experimental pain, by applying weight load to the upper arm and the lower leg, and by pinching the skin using clips. We examined whether changes in the degree of sensation with respect to electrical stimulation used in this method could be accurately observed, and whether or not it was possible to accurately and with high reproducibility measure minimum perceived current and pain equivalent current. As a result, we were able to make a clear comparison between pain and the degree of stimulation by electrical current, which was a sensation differing from pain. Although there were individual differences in the measured values, the reproducibility of the pain equivalent current as measured was favorable, and the measured values for pain ratio were also reproducible. We confirmed in the present study that the degree of experimental pain can be expressed as quantitative numerical values using an index defined as pain ratio.
著者
加藤 拓哉 関野 正樹 松崎 大河 西川 敦 齋藤 洋一 大崎 博之
出版者
公益社団法人 日本生体医工学会
雑誌
生体医工学 (ISSN:1347443X)
巻号頁・発行日
vol.50, no.1, pp.180-188, 2012-02-10 (Released:2012-07-13)
参考文献数
21

We previously proposed an eccentric figure-eight coil design which induces sufficient currents in the brain at lower output powers of stimulator. In the present study, numerical analyses were performed with various coil design parameters, such as outer and inner diameters and number of turns, to investigate the influence of these parameters on the eddy current distribution in the brain and the coil characteristics. Increases in the inner diameter, the outer diameter, and the number of turns caused increases in the induced currents. In order to downsize the stimulator system, we need to strengthen the eddy current in the brain, maintaining inductance as small as possible. Our results show that it is effective to enlarge outer diameter. In addition, there is only small difference in the eddy current distributions between the eccentric coil and the concentric coil in direction along with the coil plane and with depth of the brain.
著者
馬場 裕子 木竜 徹 山崎 健
出版者
公益社団法人 日本生体医工学会
雑誌
生体医工学 (ISSN:1347443X)
巻号頁・発行日
vol.45, no.1, pp.48-54, 2007 (Released:2008-06-05)
参考文献数
20

AIM: We investigated the differences in the occurrence of muscle fatigue depending on the contraction type and relationship between muscle fatigue and strength improvement with surface EMG (SEMG). In practice, for short-term resistance training, we studied a personally customized process for individuals. PROTOCOL: Sixteen healthy male subjects (21-23 yr-old) participated in this research. Squat exercise was preformed two times per week for six consecutive weeks. A one-day session consisted of three sets of 12 strokes. We measured the knee joint angle (KJA) with a flexibility goniometer and the muscle activity of the vastus lateralis with SEMG in each stroke of the squat exercise. Each stroke was divided into concentric and eccentric contractions referring to the KJA. SEMGs were evaluated using the average rectified value (ARV) and mean power frequency (MPF). RESULTS: For the eccentric contraction, muscular strength increased regardless of muscle fatigue. However, increasing muscular strength (r=0.49, p<0.10) correlated with the ratio of muscle fatigue occurrence for the concentric contraction. Focusing on the concentric contraction, we devised a personally customized process with the time-varying behavior of muscle fatigue. As a result, muscular strength improvement could be effectively evaluated using SEMGs.
著者
加藤 大樹 大兼 幹彦 藤原 耕輔 城野 純一 永沼 博 桂田 弘之 安藤 康夫
出版者
公益社団法人 日本生体医工学会
雑誌
生体医工学 (ISSN:1347443X)
巻号頁・発行日
vol.53, no.Supplement, pp.S187_02-S187_02, 2015 (Released:2016-07-09)

Tunnel magneto-resistance (TMR) effect can be applied to magnetic field sensors because this effect is resistance change of magnetic tunnel junctions (MTJs) by external magnetic field. We have to develop the MTJs with a very high sensitivity (=TMR/2Hk, Hk: magnetic anisotropy field) above 100%/Oe to detect a small bio-magnetic field. In this work, MTJs using CoFeSiB electrode with a low Hk were fabricated. A very high sensitivity of 115%/Oe was achieved by optimization of the CoFeSiB thickness. This sensitivity is the highest value among single MTJ devices and the MTJs with such a high sensitivity can be applied to bio-magnetic field sensor devices.
著者
小野 敦央 大兼 幹彦 永沼 博 安藤 康夫
出版者
公益社団法人 日本生体医工学会
雑誌
生体医工学 (ISSN:1347443X)
巻号頁・発行日
vol.53, no.Supplement, pp.S187_01-S187_01, 2015 (Released:2016-07-09)

Magnetic tunnel junctions (MTJs) have great advantages for the magnetic field sensor applications. However, a significant improvement of tunnel magneto-resistance (TMR) ratio is needed to detect a small bio-magnetic field. In this study, we fabricated MTJs with half-metallic Co2Fe0.4Mn0.6Si(CFMS) Heusler alloy which are expected to increase TMR ratio. The fabricated MTJswere annealed twice to achieve sensor-type TMR curves. Figure shows the 2nd annealing temperature dependence of TMR curves. In MTJ annealed at 200℃, TMR curve showed a linear resistance response, which is required for sensor applications. This work was supported by the S-Innovation program, Japan Science and Technology Agency (JST).
著者
岡田 志麻 藤原 義久 松浦 英文 安田 昌司 水貝 浩二郎 牧川 方昭 飯田 健夫
出版者
公益社団法人 日本生体医工学会
雑誌
生体医工学 (ISSN:1347443X)
巻号頁・発行日
vol.41, no.4, pp.493-497, 2003-12-10 (Released:2011-09-05)
参考文献数
6

Sleep is very important to keep our physical condition healthy. Many studies have been devoted to clarify the mechanism of sleep and to monitor the sleep all night. In this study, we paid attention to heart activity during sleep and have developed a nonrestraint monitoring method of heart activity using an acceleration sensor set inside the coverlet. This method is easy for the use of sleep monitoring at home in daily life. An acceleration sensor was set inside the coverlet as it opposing to subject's left chest. Subjects were asked to lie in supine position and the coverlet with an acceleration sensor was put on the subject. Mechanical vibration from heart activity expected to be carried to the acceleration sensor through the coverlet. As a result, periodic vibration was measured successfully and this vibration was proved to be in high correlation with the R wave of ECG in six subjects. The same results were obtained even in case of lying in right and left lateral decubitus position.