The Experts below are selected from a list of 6534 Experts worldwide ranked by ideXlab platform
Seiji Chonan - One of the best experts on this subject based on the ideXlab platform.
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a closed loop transcutaneous power transmission system with thermal control for artificial Urethral Valve driven by sma actuator
Journal of Intelligent Material Systems and Structures, 2006Co-Authors: Mami Tanaka, Kazuhiro Abe, Feng Wang, Haruo Nakagawa, Yoichi Arai, Seiji ChonanAbstract:This article presents the development of an implanted artificial Urethral Valve that is used for the treatment of urinary incontinence, with emphasis on a transcutaneous power transmission system with closed-loop thermal control function. The Valve uses a shape memory alloy (SMA) plate as the actuator, which is activated with batteries placed outside a patient’s body using a transcutaneous power transmission system. The power transmission system is equipped with an implanted temperature monitor circuit and a temperature controller to prevent the SMA actuator from being overheated during a prolonged urination. Laboratory experiments and animal experiments, both in vitro and in vivo, show that the developed power transmission system can successfully control the temperature of the SMA actuator to activate the Valve without excessive heating of the SMA actuator.
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Artificial Urethral Valve driven by SMA actuators with transcutaneous energy transmission system
International Journal of Applied Electromagnetics and Mechanics, 2003Co-Authors: Mami Tanaka, Kazuhiro Abe, Feng Wang, Haruo Nakagawa, Yoichi Arai, Yoshikatsu Tanahashi, Seiji ChonanAbstract:Abstract. This paper presents the development of a mechanical SMA Urethral Valve driven by a portable transcutaneous energytransmission system, which is powered by batteries. Structure of the Valve was improved by introducing a bite mechanism inorder to prevent the pinch of urethra by the Valve. The cycling characteristics and energy transmission efficiency were examinedby laboratory tests. Experimental results show that the stable operation can be obtained by introducing a voltage regulatingcircuit to the energy transmission system and utilizing the sinusoidal oscillation in the energy transmission system can enhancethe transmission efficiency. Furthermore, the function of the Valve system was tested by the vitro and vivo animal experiments. 1. IntroductionUrinary incontinence is the involuntary discharge of urine caused by trauma to the Urethral sphincteror the weakness of the sphincter due to aging and the expansion of the prostate gland. The early andappropriate treatment of urinary incontinence is of great importance since the incontinence might causeurinary canal infection and bedsoreif it is not treated. However, the difference in ages, sexof the patientsandthe variouscausesof thedisorder makeit difficult to treat the diseasesimplyby medicinesor surgery.On the other hand, shape memory alloys (SMAs), especially nickel-titanium alloys (nitinol, NiTi),show many unique characteristics, among them the most important two are the ability of shape recoveryand the excellent biocompatibility. For this reason, their applications to the medical field are widelystudied. Using an SMA nitinol plate as the actuator, the authors developed an artificial Urethral Valve forthe treatment of urinary incontinence [1]. TheValveis closedto clogthe involuntary dischargeof urineatthe body temperature and is opened to allow the micturition when the SMA plate is heated by runningelectric current through the nichrome wire attached to it. It is verified by the animal experiments usingcanine urethras that the Valve functions well as artificial Urethral sphincter in controlling the dischargeof urine.
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development of artificial Urethral Valve with transcutaneous energy transformer
International Journal of Applied Electromagnetics and Mechanics, 2001Co-Authors: Mami Tanaka, Yoshikatsu Tanahashi, Seiichi Orikasa, H Goto, Takasige Namima, Hidetoshi Matsuki, Seiji ChonanAbstract:This paper is concerned with the development of an artificial Urethral Valve for treating urinary incontinence, which is driven by shape memory alloy actuators. The latest Valve has been modified by adding the SMA for the closing, which has the effect of preventing incorrect actions. Further, a compact, non-contact induction heating system using power transmission coils is introduced, which is improved by using an oscillation and amplifier circuit. It is found that the Valve shows good opening and closing functions experimentally by using the urethrae of male dog through the induction-heating system. Urinary incontinence is the involuntary discharge of urine caused by the weakness of the urinary canal sphincter muscles due to aging and the expansion of the prostate gland. The difference in ages, sex of the patients and the various causes of the disorder make it difficult to treat the disease simply by drugs or surgery. Shape memory alloys (SMAs), especially nickel-titanium alloys (nitinol, NiTi), show many unique metallurgical and mechanical characteristics. One of the important features is the large change in the Young's modulus when the alloy experiences a martensitic transformation. The other is the significant shape recovery performance associated with reverse transformation of the deformed martensitic phase to the austenite phase at higher temperature. Because of its unique properties and characteristics, a great deal has been done on the metallurgical information and the applications of shape memory alloys as force and displacement actuators (1,2). For the treatment of urinary incontinence, Chonan et al. developed artificial Urethral Valve driven by SMA, nitinol plates. The SMA plate is designed to be cylindrical at the body temperature and to be flatten when heated. Heating can be done by running electric current through the copper wire attached on the surface of the plate. The plate is fixed with two semi-circular stainless steel shells to be cylindrical as a assembly. It was verified in the animal experiment using canine urethrae that the prototype Valves work
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development of an artificial Urethral Valve using sma actuators
Smart Materials and Structures, 1997Co-Authors: Seiji Chonan, Mami Tanaka, Yoshikatsu Tanahashi, Zhongwei Jiang, Junji Tani, Seiichi Orikasa, Toshiyuki Takagi, Jun TanikawaAbstract:The development of an artificial Urethral Valve for the treatment of urinary incontinence which occurs frequently in the aged is described. The prototype Urethral Valve is assembled in hand-drum form with four thin shape memory alloy (SMA) (nickel - titanium alloy) plates of 0.3 mm thickness. The shape memory effect in two directions is used to replace the urinary canal sphincter muscles and to control the canal opening and closing functions. The characteristic of the SMA is to assume the shape of a circular arc at normal temperatures and a flat shape at higher temperatures. Experiments have been conducted using a canine bladder and urinary canal.
Hideo Nakai - One of the best experts on this subject based on the ideXlab platform.
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The changes of Urethral morphology recognized in voiding cystourethrography after endoscopic transUrethral incision for posterior Urethral Valve in boys with intractable daytime urinary incontinence and nocturnal enuresis
World Journal of Urology, 2017Co-Authors: Taiju Hyuga, Shigeru Nakamura, Shina Kawai, Taro Kubo, Rieko Furukawa, Toshinori Aihara, Makiko Mieno, Hideo NakaiAbstract:Purpose Endoscopic transUrethral incision (TUI) of posterior Urethral Valve (PUV) can improve daytime urinary incontinence (DUI) and nocturnal enuresis (NE). However, the underlying mechanism has not been elucidated. In this study, we retrospectively examined the mobility of the urethra before and after TUI by measuring the Urethral angle with voiding cystourethrography (VCUG), to clarify the effects of TUI on the morphology of the urethra during voiding. Methods Between July 2010 and December 2014, 29 boys with intractable DUI and/or NE were diagnosed as PUV and underwent endoscopic TUI. VCUG during voiding phase was performed at sequential radiographic spot images (1 image per second) at a 45° angle in oblique standing position. The point at which the angle of the urethra was the smallest during urination was regarded as the minimum Urethral angle. The maximum Urethral angle during early voiding phase was compared with the minimum Urethral angle, and the percentage by which this angle changed was calculated as the flexion rate. Then changes in minimum Urethral angle and flexion rate were analyzed before and 3–4 months after TUI. Results After TUI, the minimum Urethral angle on VCUG became more obtuse (before vs. after TUI, respectively: 112.7 vs. 124.5°, p
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aggressive diagnosis and treatment for posterior Urethral Valve as an etiology for vesicoureteral reflux or urge incontinence in children
Investigative and Clinical Urology, 2017Co-Authors: Hideo Nakai, Taiju Hyuga, Shina Kawai, Taro Kubo, Shigeru NakamuraAbstract:Vesicoureteral reflux (VUR) is one of the most common diseases in pediatric urology and classified into primary and secondary VUR. Although posterior Urethral Valve (PUV) is well known as a cause of the secondary VUR, it is controversial that minor Urethral deformity recognized in voiding cystourethrography represents mild end of PUV spectrum and contributes to the secondary VUR. We have been studying for these ten years congenital Urethral obstructive lesions with special attention to its urethrographic and endoscopic morphology as well as therapeutic response with transUrethral incision. Our conclusion to date is that congenital obstructive lesion in the postero-membranous urethra is exclusively PUV (types 1 and 3) and that severity of obstruction depends on broad spectrum of morphological features recognized in PUV. Endoscopic diagnostic criteria for PUV are being consolidated.
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the changes of Urethral morphology recognized in voiding cystourethrography after endoscopic transUrethral incision for posterior Urethral Valve in boys with intractable daytime urinary incontinence and nocturnal enuresis
World Journal of Urology, 2017Co-Authors: Taiju Hyuga, Shigeru Nakamura, Shina Kawai, Taro Kubo, Rieko Furukawa, Toshinori Aihara, Makiko Mieno, Hideo NakaiAbstract:Purpose Endoscopic transUrethral incision (TUI) of posterior Urethral Valve (PUV) can improve daytime urinary incontinence (DUI) and nocturnal enuresis (NE). However, the underlying mechanism has not been elucidated. In this study, we retrospectively examined the mobility of the urethra before and after TUI by measuring the Urethral angle with voiding cystourethrography (VCUG), to clarify the effects of TUI on the morphology of the urethra during voiding.
Mami Tanaka - One of the best experts on this subject based on the ideXlab platform.
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a closed loop transcutaneous power transmission system with thermal control for artificial Urethral Valve driven by sma actuator
Journal of Intelligent Material Systems and Structures, 2006Co-Authors: Mami Tanaka, Kazuhiro Abe, Feng Wang, Haruo Nakagawa, Yoichi Arai, Seiji ChonanAbstract:This article presents the development of an implanted artificial Urethral Valve that is used for the treatment of urinary incontinence, with emphasis on a transcutaneous power transmission system with closed-loop thermal control function. The Valve uses a shape memory alloy (SMA) plate as the actuator, which is activated with batteries placed outside a patient’s body using a transcutaneous power transmission system. The power transmission system is equipped with an implanted temperature monitor circuit and a temperature controller to prevent the SMA actuator from being overheated during a prolonged urination. Laboratory experiments and animal experiments, both in vitro and in vivo, show that the developed power transmission system can successfully control the temperature of the SMA actuator to activate the Valve without excessive heating of the SMA actuator.
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Artificial Urethral Valve driven by SMA actuators with transcutaneous energy transmission system
International Journal of Applied Electromagnetics and Mechanics, 2003Co-Authors: Mami Tanaka, Kazuhiro Abe, Feng Wang, Haruo Nakagawa, Yoichi Arai, Yoshikatsu Tanahashi, Seiji ChonanAbstract:Abstract. This paper presents the development of a mechanical SMA Urethral Valve driven by a portable transcutaneous energytransmission system, which is powered by batteries. Structure of the Valve was improved by introducing a bite mechanism inorder to prevent the pinch of urethra by the Valve. The cycling characteristics and energy transmission efficiency were examinedby laboratory tests. Experimental results show that the stable operation can be obtained by introducing a voltage regulatingcircuit to the energy transmission system and utilizing the sinusoidal oscillation in the energy transmission system can enhancethe transmission efficiency. Furthermore, the function of the Valve system was tested by the vitro and vivo animal experiments. 1. IntroductionUrinary incontinence is the involuntary discharge of urine caused by trauma to the Urethral sphincteror the weakness of the sphincter due to aging and the expansion of the prostate gland. The early andappropriate treatment of urinary incontinence is of great importance since the incontinence might causeurinary canal infection and bedsoreif it is not treated. However, the difference in ages, sexof the patientsandthe variouscausesof thedisorder makeit difficult to treat the diseasesimplyby medicinesor surgery.On the other hand, shape memory alloys (SMAs), especially nickel-titanium alloys (nitinol, NiTi),show many unique characteristics, among them the most important two are the ability of shape recoveryand the excellent biocompatibility. For this reason, their applications to the medical field are widelystudied. Using an SMA nitinol plate as the actuator, the authors developed an artificial Urethral Valve forthe treatment of urinary incontinence [1]. TheValveis closedto clogthe involuntary dischargeof urineatthe body temperature and is opened to allow the micturition when the SMA plate is heated by runningelectric current through the nichrome wire attached to it. It is verified by the animal experiments usingcanine urethras that the Valve functions well as artificial Urethral sphincter in controlling the dischargeof urine.
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development of artificial Urethral Valve with transcutaneous energy transformer
International Journal of Applied Electromagnetics and Mechanics, 2001Co-Authors: Mami Tanaka, Yoshikatsu Tanahashi, Seiichi Orikasa, H Goto, Takasige Namima, Hidetoshi Matsuki, Seiji ChonanAbstract:This paper is concerned with the development of an artificial Urethral Valve for treating urinary incontinence, which is driven by shape memory alloy actuators. The latest Valve has been modified by adding the SMA for the closing, which has the effect of preventing incorrect actions. Further, a compact, non-contact induction heating system using power transmission coils is introduced, which is improved by using an oscillation and amplifier circuit. It is found that the Valve shows good opening and closing functions experimentally by using the urethrae of male dog through the induction-heating system. Urinary incontinence is the involuntary discharge of urine caused by the weakness of the urinary canal sphincter muscles due to aging and the expansion of the prostate gland. The difference in ages, sex of the patients and the various causes of the disorder make it difficult to treat the disease simply by drugs or surgery. Shape memory alloys (SMAs), especially nickel-titanium alloys (nitinol, NiTi), show many unique metallurgical and mechanical characteristics. One of the important features is the large change in the Young's modulus when the alloy experiences a martensitic transformation. The other is the significant shape recovery performance associated with reverse transformation of the deformed martensitic phase to the austenite phase at higher temperature. Because of its unique properties and characteristics, a great deal has been done on the metallurgical information and the applications of shape memory alloys as force and displacement actuators (1,2). For the treatment of urinary incontinence, Chonan et al. developed artificial Urethral Valve driven by SMA, nitinol plates. The SMA plate is designed to be cylindrical at the body temperature and to be flatten when heated. Heating can be done by running electric current through the copper wire attached on the surface of the plate. The plate is fixed with two semi-circular stainless steel shells to be cylindrical as a assembly. It was verified in the animal experiment using canine urethrae that the prototype Valves work
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development of an artificial Urethral Valve using sma actuators
Smart Materials and Structures, 1997Co-Authors: Seiji Chonan, Mami Tanaka, Yoshikatsu Tanahashi, Zhongwei Jiang, Junji Tani, Seiichi Orikasa, Toshiyuki Takagi, Jun TanikawaAbstract:The development of an artificial Urethral Valve for the treatment of urinary incontinence which occurs frequently in the aged is described. The prototype Urethral Valve is assembled in hand-drum form with four thin shape memory alloy (SMA) (nickel - titanium alloy) plates of 0.3 mm thickness. The shape memory effect in two directions is used to replace the urinary canal sphincter muscles and to control the canal opening and closing functions. The characteristic of the SMA is to assume the shape of a circular arc at normal temperatures and a flat shape at higher temperatures. Experiments have been conducted using a canine bladder and urinary canal.
Shigeru Nakamura - One of the best experts on this subject based on the ideXlab platform.
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The changes of Urethral morphology recognized in voiding cystourethrography after endoscopic transUrethral incision for posterior Urethral Valve in boys with intractable daytime urinary incontinence and nocturnal enuresis
World Journal of Urology, 2017Co-Authors: Taiju Hyuga, Shigeru Nakamura, Shina Kawai, Taro Kubo, Rieko Furukawa, Toshinori Aihara, Makiko Mieno, Hideo NakaiAbstract:Purpose Endoscopic transUrethral incision (TUI) of posterior Urethral Valve (PUV) can improve daytime urinary incontinence (DUI) and nocturnal enuresis (NE). However, the underlying mechanism has not been elucidated. In this study, we retrospectively examined the mobility of the urethra before and after TUI by measuring the Urethral angle with voiding cystourethrography (VCUG), to clarify the effects of TUI on the morphology of the urethra during voiding. Methods Between July 2010 and December 2014, 29 boys with intractable DUI and/or NE were diagnosed as PUV and underwent endoscopic TUI. VCUG during voiding phase was performed at sequential radiographic spot images (1 image per second) at a 45° angle in oblique standing position. The point at which the angle of the urethra was the smallest during urination was regarded as the minimum Urethral angle. The maximum Urethral angle during early voiding phase was compared with the minimum Urethral angle, and the percentage by which this angle changed was calculated as the flexion rate. Then changes in minimum Urethral angle and flexion rate were analyzed before and 3–4 months after TUI. Results After TUI, the minimum Urethral angle on VCUG became more obtuse (before vs. after TUI, respectively: 112.7 vs. 124.5°, p
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aggressive diagnosis and treatment for posterior Urethral Valve as an etiology for vesicoureteral reflux or urge incontinence in children
Investigative and Clinical Urology, 2017Co-Authors: Hideo Nakai, Taiju Hyuga, Shina Kawai, Taro Kubo, Shigeru NakamuraAbstract:Vesicoureteral reflux (VUR) is one of the most common diseases in pediatric urology and classified into primary and secondary VUR. Although posterior Urethral Valve (PUV) is well known as a cause of the secondary VUR, it is controversial that minor Urethral deformity recognized in voiding cystourethrography represents mild end of PUV spectrum and contributes to the secondary VUR. We have been studying for these ten years congenital Urethral obstructive lesions with special attention to its urethrographic and endoscopic morphology as well as therapeutic response with transUrethral incision. Our conclusion to date is that congenital obstructive lesion in the postero-membranous urethra is exclusively PUV (types 1 and 3) and that severity of obstruction depends on broad spectrum of morphological features recognized in PUV. Endoscopic diagnostic criteria for PUV are being consolidated.
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the changes of Urethral morphology recognized in voiding cystourethrography after endoscopic transUrethral incision for posterior Urethral Valve in boys with intractable daytime urinary incontinence and nocturnal enuresis
World Journal of Urology, 2017Co-Authors: Taiju Hyuga, Shigeru Nakamura, Shina Kawai, Taro Kubo, Rieko Furukawa, Toshinori Aihara, Makiko Mieno, Hideo NakaiAbstract:Purpose Endoscopic transUrethral incision (TUI) of posterior Urethral Valve (PUV) can improve daytime urinary incontinence (DUI) and nocturnal enuresis (NE). However, the underlying mechanism has not been elucidated. In this study, we retrospectively examined the mobility of the urethra before and after TUI by measuring the Urethral angle with voiding cystourethrography (VCUG), to clarify the effects of TUI on the morphology of the urethra during voiding.
Taiju Hyuga - One of the best experts on this subject based on the ideXlab platform.
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The changes of Urethral morphology recognized in voiding cystourethrography after endoscopic transUrethral incision for posterior Urethral Valve in boys with intractable daytime urinary incontinence and nocturnal enuresis
World Journal of Urology, 2017Co-Authors: Taiju Hyuga, Shigeru Nakamura, Shina Kawai, Taro Kubo, Rieko Furukawa, Toshinori Aihara, Makiko Mieno, Hideo NakaiAbstract:Purpose Endoscopic transUrethral incision (TUI) of posterior Urethral Valve (PUV) can improve daytime urinary incontinence (DUI) and nocturnal enuresis (NE). However, the underlying mechanism has not been elucidated. In this study, we retrospectively examined the mobility of the urethra before and after TUI by measuring the Urethral angle with voiding cystourethrography (VCUG), to clarify the effects of TUI on the morphology of the urethra during voiding. Methods Between July 2010 and December 2014, 29 boys with intractable DUI and/or NE were diagnosed as PUV and underwent endoscopic TUI. VCUG during voiding phase was performed at sequential radiographic spot images (1 image per second) at a 45° angle in oblique standing position. The point at which the angle of the urethra was the smallest during urination was regarded as the minimum Urethral angle. The maximum Urethral angle during early voiding phase was compared with the minimum Urethral angle, and the percentage by which this angle changed was calculated as the flexion rate. Then changes in minimum Urethral angle and flexion rate were analyzed before and 3–4 months after TUI. Results After TUI, the minimum Urethral angle on VCUG became more obtuse (before vs. after TUI, respectively: 112.7 vs. 124.5°, p
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aggressive diagnosis and treatment for posterior Urethral Valve as an etiology for vesicoureteral reflux or urge incontinence in children
Investigative and Clinical Urology, 2017Co-Authors: Hideo Nakai, Taiju Hyuga, Shina Kawai, Taro Kubo, Shigeru NakamuraAbstract:Vesicoureteral reflux (VUR) is one of the most common diseases in pediatric urology and classified into primary and secondary VUR. Although posterior Urethral Valve (PUV) is well known as a cause of the secondary VUR, it is controversial that minor Urethral deformity recognized in voiding cystourethrography represents mild end of PUV spectrum and contributes to the secondary VUR. We have been studying for these ten years congenital Urethral obstructive lesions with special attention to its urethrographic and endoscopic morphology as well as therapeutic response with transUrethral incision. Our conclusion to date is that congenital obstructive lesion in the postero-membranous urethra is exclusively PUV (types 1 and 3) and that severity of obstruction depends on broad spectrum of morphological features recognized in PUV. Endoscopic diagnostic criteria for PUV are being consolidated.
-
the changes of Urethral morphology recognized in voiding cystourethrography after endoscopic transUrethral incision for posterior Urethral Valve in boys with intractable daytime urinary incontinence and nocturnal enuresis
World Journal of Urology, 2017Co-Authors: Taiju Hyuga, Shigeru Nakamura, Shina Kawai, Taro Kubo, Rieko Furukawa, Toshinori Aihara, Makiko Mieno, Hideo NakaiAbstract:Purpose Endoscopic transUrethral incision (TUI) of posterior Urethral Valve (PUV) can improve daytime urinary incontinence (DUI) and nocturnal enuresis (NE). However, the underlying mechanism has not been elucidated. In this study, we retrospectively examined the mobility of the urethra before and after TUI by measuring the Urethral angle with voiding cystourethrography (VCUG), to clarify the effects of TUI on the morphology of the urethra during voiding.
