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Seki, Takeshi*; Naganawa, Akihiro*; Oka, Kiyoshi; Yoshino, Junji*
Keisoku Jido Seigyo Gakkai Sangyo Rombunshu, 10(2), p.7 - 16, 2011/05
Enteroscopy was usually performed by the double balloon or capsule endoscopes. However, it is difficult to use these endoscopes in patients who suffer from intestinal obstruction and adhesion. We have developed a new endoscope that can be used in patients who suffer from these problems; the instrument consists of an ileus tube and an optical fiberscope (diameter 1.1 mm). The entire small intestine can be observed by controlling the internal pressure of the balloon in the ileus tube and by pulling the tube out at a constant speed. In our previous study, we developed an internal pressure control device that consists of a balloon attached to an ileus tube and a medical syringe. We also verified the control performance of this device. In this study, we have designed a new two-degrees-of-freedom control system having self-tuning capabilities that enhances the control performance for various types of syringes doctors use usually. The effects of the proposed method are illustrated by the experiment. The obtained results show that balloon pressure in the reference response satisfactorily tracks the output of the reference model and can be settled within 
2% in steady state. In addition, the disturbance rejection properties of the PID control method were affected by the changes in balloon pressure, but this problem can be solved by using the proposed control system.
Seki, Takeshi; Naganawa, Akihiro*; Oka, Kiyoshi; Ishikawa, Shinji*; Yoshino, Junji*
Nihon Kikai Gakkai Rombunshu, C, 76(766), p.1645 - 1647, 2010/06
Recently, by development of double balloon and capsule endoscopes, small intestinal whole area observation was enabled. However, it is difficult to use these endoscopes in patients with intestinal obstruction and adhesion. We developed a new endoscope that can be used in patients with intestinal obstruction and adhesion; this instrument consists of an ileus tube and an optical fiberscope (diameter, 1.1 mm). The complete observation of small intestinal is to be planned by controlling internal pressure of balloon in ileus tube, and pulling the tube out at constant speed. In our previous study, we have developed an internal pressure control device which consists of a balloon of ileus and an industrial cylinder, and we confirmed the utility. In this study, we developed a new control device combined with a general medical syringe, which enables to be sterilized easily and also to give less anxiety to patients. As the results of performance experiment of the device, the control accuracy was within 0.5% error. Furthermore, in a disturbance response, the pressure fluctuation was limited down to 12%, compared with a case without any control.
Oka, Kiyoshi; Seki, Takeshi*; Naito, Takehito*; Watanabe, Shinya*; Wakabayashi, Takao*; Naganawa, Akihiro*; Inui, Kazuo*; Yoshino, Junji*
Nihon Gazo Igaku Zasshi, 28(1), p.12 - 24, 2010/05
Focusing on the measurement function loaded on our rigid-typed endoscope for the fetal surgery treatment, we proposed that its combination with a generally used digestive endoscope enabled calibration of lesion size in stomach. While adding the function, with which the target size is to be easily measured, on the endoscope, we simplified the system structure as much as possible. We also tried to minimize the total cost by using the generally used endoscope, instead of making it from scratch. Combining another development, the composite-type optical fiberscope with diameter of 1.1mm, with a generally used endoscope, we proposed the following as the features: (1)acquisition of fiberscope image, (2)laser irradiation for treatments, (3)applying the real time measurement function of distance and blood flow by semiconductor laser to the generally used endoscope. We have operated the clinical study to the gastric wall of person with no health problem, using this system and confirmed it was available for practical use.
Seki, Takeshi*; Naganawa, Akihiro*; Oka, Kiyoshi; Yoshino, Junji*
Nihon Kompyuta Geka Gakkai-Shi, 12(1), p.33 - 42, 2010/03
no abstracts in English
Ishikawa, Noriko; Oka, Kiyoshi; Naganawa, Akihiro*; Yoshino, Junji*; Wakabayashi, Takao*; Watanabe, Shinya*; Naito, Takehito*
Nihon Kikai Gakkai Rombunshu, C, 75(756), p.2359 - 2361, 2009/08
Instruments for measuring the internal pressure of digestive organs are used for diagnosing functional diseases, judging how critical the condition is, and deciding the treatment method or determining the degree of alleviation. However, the technique wherein the internal pressure of the small intestine is measured is highly invasive and painful for patients, and the insertion of the catheter via transducers is not preferred because it involves the insertion of an electric instrument in the body. In this study, we developed a system that measures the pressure of the small intestine with an ileus tube, which is generally used for the treatment of ileus. The main feature of our system is that can be used to measure internal pressure without the insertion of electric instruments such as transducers into the body, allowing the assessment of ileus without causing pain to the patient being treated. In this note, we present a brief description of the structure and function of this instrument used to measure the internal pressure of the small intestine.
Sugihara, Masayoshi; Lukash, V.*; Kawano, Yasunori; Yoshino, Ryuji; Gribov, Y.*; Khayrutdinov, R.*; Miki, Nobuharu*; Omori, Junji*; Shimada, Michiya
Proceedings of 30th EPS Conference on Controlled Fusion and Plasma Physics (CD-ROM), 4 Pages, 2003/07
We examine plasma behaviours during plasma disruptions in detail in JT-60U and other tokamaks to derive appropriate physics guidelines for the behaviours. Their interpretations and their extrapolations to ITER are incorporated into the DINA code, which solves plasma transport and 2D free boundary plasma equilibrium simultaneously with circuit equations for the vacuum vessel and the PF coils. Sensitivity of the plasma behaviours and their impact on the EM force during disruptions due to the range of variation and uncertainty of the experimental data are examined.
Sugihara, Masayoshi; Lukash, V.*; Kawano, Yasunori; Yoshino, Ryuji; Gribov, Y.*; Khayrutdinov, R.*; Miki, Nobuharu*; Omori, Junji*; Shimada, Michiya
Purazuma, Kaku Yugo Gakkai-Shi, 79(7), p.706 - 712, 2003/07
The time dependence of the current decay during the current quench phase of disruptions, which can significantly influence the electro-magnetic force on the in-vessel components due to the induced eddy currents, is investigated using data obtained in JT-60U experiments in order to derive a relevant physics guideline for the predictive simulations of disruptions in ITER. It is shown that an exponential decay can fit the time dependence of current quench for discharges with large quench rate (fast current quench). On the other hand, for discharges with smaller quench rate (slow current quench), a linear decay can fit the time dependence of current quench better than exponential.
Seki, Takeshi*; Naganawa, Akihiro*; Oka, Kiyoshi; Yoshino, Junji*
no journal, ,
no abstracts in English
Ishikawa, Shinji*; Seki, Takeshi*; Naganawa, Akihiro*; Oka, Kiyoshi; Yoshino, Junji*
no journal, ,
no abstracts in English
Saga, Ryusuke*; Naganawa, Akihiro*; Seki, Takeshi*; Oka, Kiyoshi; Yoshino, Junji*
no journal, ,
no abstracts in English
Seki, Takeshi; Naganawa, Akihiro*; Oka, Kiyoshi; Sato, Noriyasu*; Yoshino, Junji*
no journal, ,
The double-balloon and capsule endoscopes are difficult to use such endoscopes in patients who suffer from intestinal obstruction and adhesion. We have developed a new endoscope that can be used in patients who suffer from these problems; the device consists of an ileus tube and an optical fiberscope (1.1 mm in diameter). When this endoscope is removed from the body at a constant speed, the entire small intestine can be observed by controlling the internal pressure of balloons of the ileus tube to sufficiently maintain the state of the bowel. In this research, we developed a device to control the internal pressure of the balloon to facilitate the observation of the entire small intestinal area. The internal pressure control device developed by us consists of an ileus tube, a medical syringe, a motor, a pressure sensor, and so on. The medical syringe is used to control the balloon's internal pressure by pushing and pulling the plunger using the motor. To realize a very accurate control performance, we incorporated a two-degrees-of-freedom control system to control the balloon internal pressure. We experimented on three aspects of the device to evaluate its performance (Reference response property, Disturbance rejection property and Maintenance of pressure level). These results suggested that it is possible to remove the ileus tube from the small intestine at a constant speed.
Narita, Yasuki*; Yoshino, Junji*; Inui, Kazuo*; Wakabayashi, Takao*; Kobayashi, Takashi*; Miyoshi, Hironao*; Kosaka, Toshihito*; Tomomatsu, Yuichiro*; Yamamoto, Satoshi*; Matsuura, Hironao*; et al.
no journal, ,
no abstracts in English
Komatsu, Kazumi*; Naganawa, Akihiro*; Seki, Takeshi; Oka, Kiyoshi; Yoshino, Junji*
no journal, ,
no abstracts in English
Naganawa, Akihiro*; Nagata, Keisuke*; Oka, Kiyoshi; Seki, Takeshi; Narita, Yasuki*; Yoshino, Junji*
no journal, ,
no abstracts in English
Naganawa, Akihiro*; Oka, Kiyoshi; Narita, Yasuki*; Yoshino, Junji*; Inui, Kazuo*
no journal, ,
no abstracts in English
