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Yasunaga S, Takahashi H, Takahata T, Shimoyama I. MEMS Differential Pressure Sensor with Dynamic Pressure Canceler for Precision Altitude Estimation. Micromachines (Basel) 2023; 14:1941. [PMID: 37893379 PMCID: PMC10609560 DOI: 10.3390/mi14101941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 10/14/2023] [Accepted: 10/16/2023] [Indexed: 10/29/2023]
Abstract
Atmospheric pressure measurements based on microelectromechanical systems (MEMSs) can extend accessibility to altitude information. A differential pressure sensor using a thin cantilever and an air chamber is a promising sensing element for sub-centimeter resolution. However, its vulnerability to wind and the lack of height estimation algorithms for real-time operation are issues that remain to be solved. We propose a sensor "cap" that cancels the wind effect and noise by utilizing the airflow around a sphere. A set of holes on the spherical cap transmits only the atmospheric pressure to the sensor. In addition, we have developed a height estimation method based on a discrete transfer function model. As a result, both dynamic pressure and noise are suppressed, and height is estimated under a 5 m/s wind, reconstructing the trajectory with an estimation error of 2.8 cm. The developed sensing system enhances height information in outdoor applications such as unmanned aerial vehicles and wave height measurements.
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Affiliation(s)
- Shun Yasunaga
- Department of Electrical Engineering and Information Systems, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan;
| | - Hidetoshi Takahashi
- Department of Mechanical Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kouhoku-ku, Yokohama 223-8522, Kanagawa, Japan;
| | - Tomoyuki Takahata
- Department of Advanced Machinery Engineering, School of Engineering, Tokyo Denki University, 5 Senju Asahi-cho, Adachi-ku, Tokyo 120-8551, Japan;
| | - Isao Shimoyama
- Imizu Campus, Toyama Prefectural University, 5180 Kurokawa, Imizu 939-0398, Toyama, Japan
- Hongo Campus, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
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2
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Ikegami R, Tsukagoshi T, Matsudaira K, Shoji KH, Takahashi H, Nguyen TV, Tamamoto T, Noda K, Koyanagi K, Oshima T, Shimoyama I. Temperature Dependence of the Beating Frequency of hiPSC-CMs Using a MEMS Force Sensor. Sensors (Basel) 2023; 23:3370. [PMID: 37050430 PMCID: PMC10098744 DOI: 10.3390/s23073370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 03/17/2023] [Accepted: 03/20/2023] [Indexed: 06/19/2023]
Abstract
It is expected that human iPS cell-derived cardiomyocytes (hiPSC-CMs) can be used to treat serious heart diseases. However, the properties and functions of human adult cardiomyocytes and hiPSC-CMs, including cell maturation, differ. In this study, we focused on the temperature dependence of hiPSC-CMs by integrating the temperature regulation system into our sensor platform, which can directly and quantitatively measure their mechanical motion. We measured the beating frequency of hiPSC-CMs at different environmental temperatures and found that the beating frequency increased as the temperature increased. Although the rate at which the beating frequency increased with temperature varied, the temperature at which the beating stopped was relatively stable at approximately 20 °C. The stopping of beating at this temperature was stable, even in immature hiPSC-CMs, and was considered to be a primitive property of cardiomyocytes.
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Affiliation(s)
- Ryota Ikegami
- Department of Intelligent Robotics, Faculty of Engineering, Toyama Prefectural University, Imizu 939-0398, Japan
| | - Takuya Tsukagoshi
- Department of Intelligent Robotics, Faculty of Engineering, Toyama Prefectural University, Imizu 939-0398, Japan
| | - Kenei Matsudaira
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, The University of Tokyo, Tokyo 113-8654, Japan
| | - Kayoko Hirayama Shoji
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, The University of Tokyo, Tokyo 113-8654, Japan
| | - Hidetoshi Takahashi
- Department of Mechanical Engineering, Faculty of Science and Technology, Keio University, Yokohama 223-8522, Japan
| | - Thanh-Vinh Nguyen
- Sensing System Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8564, Japan
| | - Takumi Tamamoto
- Department of Intelligent Mechanical Engineering, Faculty of Engineering, Fukuoka Institute of Technology, Fukuoka 811-0295, Japan
| | - Kentaro Noda
- Department of Intelligent Robotics, Faculty of Engineering, Toyama Prefectural University, Imizu 939-0398, Japan
| | - Ken’ichi Koyanagi
- Department of Intelligent Robotics, Faculty of Engineering, Toyama Prefectural University, Imizu 939-0398, Japan
| | - Toru Oshima
- Department of Intelligent Robotics, Faculty of Engineering, Toyama Prefectural University, Imizu 939-0398, Japan
| | - Isao Shimoyama
- Toyama Prefectural University, Imizu 939-0398, Japan
- The University of Tokyo, Tokyo 113-8654, Japan
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3
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Oladazimi M, Putelat T, Szalai R, Noda K, Shimoyama I, Champneys A, Schwarz C. Publisher Correction: Conveyance of texture signals along a rat whisker. Sci Rep 2021; 11:24233. [PMID: 34907315 PMCID: PMC8671386 DOI: 10.1038/s41598-021-03545-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Maysam Oladazimi
- Systems Neurophysiology, Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, Otfried Müller Str. 25, 72076, Tübingen, Germany.,Systems Neurophysiology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Thibaut Putelat
- Department of Engineering Mathematics, University of Bristol, Bristol, BS8 1UB, UK.,Department of Sustainable Agriculture Sciences, Rothamsted Research, Harpenden, AL5 2JQ, UK
| | - Robert Szalai
- Department of Engineering Mathematics, University of Bristol, Bristol, BS8 1UB, UK
| | - Kentaro Noda
- Department of Mechano‑Informatics, Graduate School of Information Science and Technology, University of Tokyo, Tokyo, Japan.,Department of Intelligent Robotics, Toyama Prefectural University, Toyama, Japan
| | - Isao Shimoyama
- Department of Mechano‑Informatics, Graduate School of Information Science and Technology, University of Tokyo, Tokyo, Japan.,Toyama Prefectural University, Toyama, Japan
| | - Alan Champneys
- Department of Engineering Mathematics, University of Bristol, Bristol, BS8 1UB, UK
| | - Cornelius Schwarz
- Systems Neurophysiology, Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, Otfried Müller Str. 25, 72076, Tübingen, Germany. .,Systems Neurophysiology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.
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5
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Oladazimi M, Putelat T, Szalai R, Noda K, Shimoyama I, Champneys A, Schwarz C. Conveyance of texture signals along a rat whisker. Sci Rep 2021; 11:13570. [PMID: 34193889 PMCID: PMC8245408 DOI: 10.1038/s41598-021-92770-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 06/07/2021] [Indexed: 11/09/2022] Open
Abstract
Neuronal activities underlying a percept are constrained by the physics of sensory signals. In the tactile sense such constraints are frictional stick-slip events, occurring, amongst other vibrotactile features, when tactile sensors are in contact with objects. We reveal new biomechanical phenomena about the transmission of these microNewton forces at the tip of a rat's whisker, where they occur, to the base where they engage primary afferents. Using high resolution videography and accurate measurement of axial and normal forces at the follicle, we show that the conical and curved rat whisker acts as a sign-converting amplification filter for moment to robustly engage primary afferents. Furthermore, we present a model based on geometrically nonlinear Cosserat rod theory and a friction model that recreates the observed whole-beam whisker dynamics. The model quantifies the relation between kinematics (positions and velocities) and dynamic variables (forces and moments). Thus, only videographic assessment of acceleration is required to estimate forces and moments measured by the primary afferents. Our study highlights how sensory systems deal with complex physical constraints of perceptual targets and sensors.
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Affiliation(s)
- Maysam Oladazimi
- Systems Neurophysiology, Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, Otfried Müller Str. 25, 72076, Tübingen, Germany.,Systems Neurophysiology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Thibaut Putelat
- Department of Engineering Mathematics, University of Bristol, Bristol, BS8 1UB, UK.,Department of Sustainable Agriculture Sciences, Rothamsted Research, Harpenden, AL5 2JQ, UK
| | - Robert Szalai
- Department of Engineering Mathematics, University of Bristol, Bristol, BS8 1UB, UK
| | - Kentaro Noda
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, University of Tokyo, Tokyo, Japan.,Department of Intelligent Robotics, Toyama Prefectural University, Toyama, Japan
| | - Isao Shimoyama
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, University of Tokyo, Tokyo, Japan.,Toyama Prefectural University, Toyama, Japan
| | - Alan Champneys
- Department of Engineering Mathematics, University of Bristol, Bristol, BS8 1UB, UK
| | - Cornelius Schwarz
- Systems Neurophysiology, Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, Otfried Müller Str. 25, 72076, Tübingen, Germany. .,Systems Neurophysiology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.
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6
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Okuda Y, Nakai A, Sato T, Kurata M, Shimoyama I, Oda T, Ohkohci N. New device with force sensors for laparoscopic liver resection - investigation of grip force and histological damage. MINIM INVASIV THER 2020; 31:28-33. [PMID: 32468887 DOI: 10.1080/13645706.2020.1755313] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Introduction: As the benefits of minimally invasive surgery are recognized, the rate of laparoscopic liver resection (LLR) is rapidly increasing. Liver tissue is fragile compared to tissue of the stomach and colon. In endoscopic and robotic surgery, sufficient tactile sensation is yet to be obtained. Therefore, it is necessary to measure and indicate the grip force of forceps during surgery. We developed a new device consisting of force sensors and investigated its grip force and the resulting histological damage to liver tissue.Material and methods: We measured the grip force generated during laparoscopic surgery in pigs using the forceps with pressure sensors developed by us. Throughout the hepatectomy, we measured the grip force generated by the forceps in real time. We investigated the histological damage to the liver caused by using the forceps with different grip forces.Results: The subject produced a mean grip force of 1.75 N during the procedures. The maximum grip force was 3.38 N. By grasping the tissues of the liver with forceps, bleeding and destruction of the hepatic lobules were observed in a manner dependent on increasing grip force.Conclusion: The new device is necessary for preventing liver damage in laparoscopic hepatic resection.
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Affiliation(s)
- Yoichi Okuda
- Department of Surgery, Division of Gastroenterological and Hepatobiliary Surgery, and Organ Transplantation, University of Tsukuba, Tsukuba, Japan.,Mito Chuo Hospital, Mito, Japan
| | - Akihito Nakai
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, University of Tokyo, Tokyo, Japan
| | - Taiki Sato
- Department of Pathology, Faculty of Medicine, Diagnostic Pathology, University of Tsukuba Hospital, Tsukuba, Japan
| | - Masano Kurata
- Department of Surgery, Division of Gastroenterological and Hepatobiliary Surgery, and Organ Transplantation, University of Tsukuba, Tsukuba, Japan
| | - Isao Shimoyama
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, University of Tokyo, Tokyo, Japan
| | - Tatsuya Oda
- Department of Surgery, Division of Gastroenterological and Hepatobiliary Surgery, and Organ Transplantation, University of Tsukuba, Tsukuba, Japan
| | - Nobhuhiro Ohkohci
- Department of Surgery, Division of Gastroenterological and Hepatobiliary Surgery, and Organ Transplantation, University of Tsukuba, Tsukuba, Japan.,Mito Chuo Hospital, Mito, Japan
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7
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Takeda M, Shimoyama I. Analysis of the Vertical Driving Performance of Multiple Connected Pipe-Climbing Microrobots with Magnetic Wheels. Micromachines (Basel) 2019; 10:mi10080524. [PMID: 31395794 PMCID: PMC6724032 DOI: 10.3390/mi10080524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 08/04/2019] [Accepted: 08/06/2019] [Indexed: 06/10/2023]
Abstract
In this study, we analyzed the vertical driving performance of multiple connected magnetic wheel-driven microrobots when moving up and down a small cylinder that simulated a pipe. The dynamics of pipe climbing by the magnetic wheel-driven microrobot were analyzed considering the magnetic attraction force and slip; a vertical climbing simulator was developed considering the hoop force and external force from the adjacent microrobots to determine the magnetic attraction force required for multiple connected microrobot pipe climbing. A prototype of an independent vertical climbing microrobot, 5 mm long, 9 mm wide, and 6.5 mm high, and prototypes of 10 microrobots were manufactured to evaluate the vertical driving performance. The usefulness was verified by showing that three driving microrobots can move seven non-driving microrobots comprising 60% of their own weight up and down along a small cylinder.
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Affiliation(s)
- Munehisa Takeda
- MEMS System Development Center, Micromachine Center, Tokyo 101-0026, Japan.
| | - Isao Shimoyama
- Toyama Prefectural University, Imizu 939-0398, Japan
- Graduate School of Information Science and Technology, The University of Tokyo, Tokyo 113-8656, Japan
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8
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Saito Y, Yamamoto Y, Kan T, Tsukagoshi T, Noda K, Shimoyama I. Electrical detection SPR sensor with grating coupled backside illumination. Opt Express 2019; 27:17763-17770. [PMID: 31252731 DOI: 10.1364/oe.27.017763] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 05/24/2019] [Indexed: 06/09/2023]
Abstract
A current detection surface plasmon resonance (SPR) sensor with an Au grating on an n-Si wafer was proposed. SPR excitation light is illuminated from the backside of the device and diffracted by the grating. Since the diffraction provides matching conditions, SPR can be coupled to the Au/analyte interface. Since the coupled SPR excites free electrons on the Au surface, the SPR can be detected as a current signal by a Schottky barrier diode formed on the Au/n-Si interface. The obtained angular current spectrum showed clear agreement with SPR coupling theory, thereby confirming that the sample on the Au surface can be electrically detected using the proposed sensor.
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9
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Takeda M, Shimoyama I. Slip and Magnetic Attraction Effects in a Microrobot with Magnetic-Wheels and Skid-Steering. Micromachines (Basel) 2019; 10:E379. [PMID: 31174323 PMCID: PMC6631120 DOI: 10.3390/mi10060379] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 05/31/2019] [Accepted: 06/03/2019] [Indexed: 12/04/2022]
Abstract
This study investigated slip and magnetic attraction effects in a skid-steered magnetic-wheeled microrobot. The dynamics of the microrobot were derived by considering the slip and magnetic attraction of the wheels. In addition, the slip characteristics of the magnetic wheels were measured using an evaluation apparatus built for this purpose. A simulation program for driving performance was developed as well. Simulations indicated that the turning characteristics of the skid-steered wheeled microrobot degrade because the gripping force decreases due to the decrease in weight with decreasing size. However, the turning characteristics of a skid-steered microrobot can be improved with the magnetic attraction of magnetic wheels. A 5 mm × 9 mm × 6.5 mm skid-steered microrobot with four magnetic wheels was fabricated, and the measured performance was consistent with the simulation results. The differences in driving performance were clarified between a microrobot with column-type magnetic wheels and one with barrel-type magnetic wheels, as well as between forward and backward motion.
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Affiliation(s)
- Munehisa Takeda
- MEMS System Development Center, Micromachine Center, Tokyo 101-0026, Japan.
| | - Isao Shimoyama
- Toyama Prefectural University, Imizu 939-0398, Japan.
- Graduate School of Information Science and Technology, The University of Tokyo, Tokyo 113-8656, Japan.
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10
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Tsukagoshi T, Kuroda Y, Noda K, Binh-Khiem N, Kan T, Shimoyama I. Compact Surface Plasmon Resonance System with Au/Si Schottky Barrier. Sensors (Basel) 2018; 18:s18020399. [PMID: 29385726 PMCID: PMC5855120 DOI: 10.3390/s18020399] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 01/25/2018] [Accepted: 01/27/2018] [Indexed: 11/16/2022]
Abstract
Ethanol concentration was quantified by the use of a compact surface plasmon resonance (SPR) system, which electrically detects hot electrons via a Schottky barrier. Although it is well known that SPR can be used as bio/chemical sensors, implementation is not necessarily practical, due to the size and cost impediments associated with a system with variable wavelength or angle of incidence. However, scanning capability is not a prerequisite if the objective is to use SPR in a sensor. It is possible to build a small, inexpensive SPR sensor if the optics have no moving parts and a Schottky barrier is used for electrical current detection in place of a photodetector. This article reports on the design and performance of such a novel SPR sensor, and its application for quantifying ethanol concentration. As the concentration of ethanol is increased, the change in the angle dependence of the SPR current is observed. This change can be understood as a superposition of contributions of SPR coupled with the +3rd- and -3rd-order diffraction. Moreover, real-time monitoring of ethanol concentration was demonstrated using the proposed SPR system.
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Affiliation(s)
- Takuya Tsukagoshi
- Information and Robot Technology Research Initiative, The University of Tokyo, Tokyo 113-8656, Japan.
| | - Yuta Kuroda
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, The University of Tokyo, Tokyo 113-8656, Japan.
| | - Kentaro Noda
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, The University of Tokyo, Tokyo 113-8656, Japan.
| | - Nguyen Binh-Khiem
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, The University of Tokyo, Tokyo 113-8656, Japan.
| | - Tetsuo Kan
- Graduate School of Informatics and Engineering, The University of Electro-Communications, Tokyo 182-8585, Japan.
| | - Isao Shimoyama
- Information and Robot Technology Research Initiative, The University of Tokyo, Tokyo 113-8656, Japan.
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, The University of Tokyo, Tokyo 113-8656, Japan.
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11
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Hori M, Nakai A, Shimoyama I. Three-Axis Ground Reaction Force Distribution during Straight Walking. Sensors (Basel) 2017; 17:s17102431. [PMID: 29064385 PMCID: PMC5677223 DOI: 10.3390/s17102431] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 10/12/2017] [Accepted: 10/19/2017] [Indexed: 11/27/2022]
Abstract
We measured the three-axis ground reaction force (GRF) distribution during straight walking. Small three-axis force sensors composed of rubber and sensor chips were fabricated and calibrated. After sensor calibration, 16 force sensors were attached to the left shoe. The three-axis force distribution during straight walking was measured, and the local features of the three-axis force under the sole of the shoe were analyzed. The heel area played a role in receiving the braking force, the base area of the fourth and fifth toes applied little vertical or shear force, the base area of the second and third toes generated a portion of the propulsive force and received a large vertical force, and the base area of the big toe helped move the body’s center of mass to the other foot. The results demonstrate that measuring the three-axis GRF distribution is useful for a detailed analysis of bipedal locomotion.
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Affiliation(s)
- Masataka Hori
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
| | - Akihito Nakai
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
| | - Isao Shimoyama
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
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12
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Chen W, Kan T, Ajiki Y, Matsumoto K, Shimoyama I. NIR spectrometer using a Schottky photodetector enhanced by grating-based SPR. Opt Express 2016; 24:25797-25804. [PMID: 27828514 DOI: 10.1364/oe.24.025797] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We present a near-infrared (NIR) spectrum measurement method using a Schottky photodetector enhanced by surface plasmon resonance (SPR). An Au grating was fabricated on an n-type silicon wafer to form a Schottky barrier and act as an SPR coupler. The resulting photodetector provides wavelength-selective photodetection depending on the SPR coupling angle. A matrix was pre-calculated to describe this characteristic. The spectrum was obtained from this matrix and the measured photocurrents at various SPR coupling angles. Light with single and multiple wavelengths was tested. Comparative measurements showed that our method is able to detect spectra with a wavelength resolution comparable to that of a commercial spectrometer.
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13
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Nguyen TV, Tsukagoshi T, Takahashi H, Matsumoto K, Shimoyama I. Depinning-Induced Capillary Wave during the Sliding of a Droplet on a Textured Surface. Langmuir 2016; 32:9523-9529. [PMID: 27603591 DOI: 10.1021/acs.langmuir.6b02762] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Surfaces covered with hydrophobic micro-/nanoscale textures can allow water droplets to slide easily because of low contact angle hysteresis. In contrast to the case of a droplet sliding on a smooth surface, when a droplet slides on a textured surface, it must recede from the textures at its rear edge and the resultant depinning events induce a capillary wave on the surface of the droplet. Although this depinning-induced capillary wave can be observed to some extent through high-speed imaging, important parameters of the wave, such as the wavelength and frequency, and the factors that determine these parameters are not fully understood. We report direct measurements of this depinning-induced capillary wave using microelectromechanical systems (MEMS)-based force sensors fabricated on a textured surface. Such sensor measurements reveal the frequency of the vibration occurring on the surface of the droplet, from which it is possible to calculate the wavelength of the capillary wave. We show that the frequency and wavelength of the depinning-induced capillary wave during the sliding of a water droplet on a micropillar array depend upon neither the size of the droplet nor its sliding velocity. However, the frequency (wavelength) decreases (increases) as the pitch of the micropillar array increases. We argue that the wavelength of the depinning-induced capillary wave is equal to the maximum length of the liquid bridges that develop at the micropillars before depinning. This hypothesis is confirmed by comparing the wavelengths obtained from the sensor measurements to the maximum liquid-bridge lengths calculated from observations using a high-speed camera.
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Affiliation(s)
| | | | | | - Kiyoshi Matsumoto
- Faculty of Science and Engineering, Toyo University , 2100 Kujirai, Kawagoe-shi, Saitama 350-8585, Japan
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Abstract
In this paper, the pheromone-oriented behavior of moths will be demonstrated by synthesis with biosensors and a small mobile robot that is controlled by recurrent neural networks. Since antennae on a silkworm moth are very sensitive as compared to conventional arti ficial gas sensors, they can be used as living gas sensors that detect pheromone molecules. A simple recurrent artificial neural network was used to control pheromone-tracing behavior in the manner of a living male silkworm moth. This neural network generates mothlike behavior while interacting with the environment. The turning behav ior, in particular, is a suitable tactic for small intelligence when a robot misses pheromone molecules. Our neural network is so simple that it can be very easily used as the controlling devices for micro- robots, which have a small amount of space for intelligence. Our robot is a hybrid system that combines living organisms and artificial machines, and is therefore a new type of robot. This approach has the advantage of a real-world experiment with biosensors instead of computer simulation. The difference between the real world and the simulation conditions yields a discrepancy in results. An additional discrepancy is generated by the sensor model. Therefore, real-world experiments with living antennae may provide a fascinating interface between computer simulation and neuroethology.
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Affiliation(s)
- Yoshihiko Kuwana
- Department of Mechano-Informatics The University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113, Japan
| | - Isao Shimoyama
- Department of Mechano-Informatics The University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113, Japan
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15
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Abstract
The authors have developed five kinds of biped locomotive robots so far. They are named BIPER-1, 2, 3, 4, and 5. All of them are statically unstable but can perform a dynamically stable walk with suitable control. BIPER-1 and BIPER-2 walk only sideways. BIPER-3 is a stilt-type robot whose foot contacts occur at a point and who can walk sideways, back ward, and forward. BIPER-4's legs have the same degrees of freedom as human legs. BIPER-5 is similar to BIPER-3, but in the case of BIPER-5 all apparatus, such as the computer, are mounted on it. This paper deals with the control theory used for BIPER-3 and BIPER-4. In both cases, basically the same control method is applied. The most important point is that the mo tion of either robot during the single-leg support phase can be approximated by the motion of an inverted pendulum. Ac cordingly, in this paper, dynamic walk is considered to be a series of inverted-pendulum motions with appropriate condi tions of connection.
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Affiliation(s)
- Hirofumi Miura
- Department of Mechanical Engineering Faculty of Engineering University of Tokyo Bunkyo-ku, Tokyo, 113 Japan
| | - Isao Shimoyama
- Department of Mechanical Engineering Faculty of Engineering University of Tokyo Bunkyo-ku, Tokyo, 113 Japan
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16
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Takahashi H, Jung Heo Y, Arakawa N, Kan T, Matsumoto K, Kawano R, Shimoyama I. Scalable fabrication of microneedle arrays via spatially controlled UV exposure. Microsyst Nanoeng 2016; 2:16049. [PMID: 31057837 PMCID: PMC6444715 DOI: 10.1038/micronano.2016.49] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 06/25/2016] [Accepted: 06/27/2016] [Indexed: 05/05/2023]
Abstract
This paper describes a theoretical estimation of the geometry of negative epoxy-resist microneedles prepared via inclined/rotated ultraviolet (UV) lithography based on spatially controlled UV exposure doses. In comparison with other methods based on UV lithography, the present method can create microneedle structures with high scalability. When negative photoresist is exposed to inclined/rotated UV through circular mask patterns, a three-dimensional, needle-shaped distribution of the exposure dose forms in the irradiated region. Controlling the inclination angles and the exposure dose modifies the photo-polymerized portion of the photoresist, thus allowing the variation of the heights and contours of microneedles formed by using the same mask patterns. In an experimental study, the dimensions of the fabricated needles agreed well with the theoretical predictions for varying inclination angles and exposure doses. These results demonstrate that our theoretical approach can provide a simple route for fabricating microneedles with on-demand geometry. The fabricated microneedles can be used as solid microneedles or as a mold master for dissolving microneedles, thus simplifying the microneedle fabrication process. We envision that this method can improve fabrication accuracy and reduce fabrication cost and time, thereby facilitating the practical applications of microneedle-based drug delivery technology.
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Affiliation(s)
- Hidetoshi Takahashi
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Yun Jung Heo
- Department of Mechanical Systems Engineering, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei-shi, Tokyo 184-8588, Japan
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| | - Nobuchika Arakawa
- Department of Mechanical Systems Engineering, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei-shi, Tokyo 184-8588, Japan
| | - Tesuo Kan
- Department of Mechanical Engineering and Intelligent Systems, Graduate School of Informatics and Engineering, the University of Electro-Communications, 1-5-1 Chofugaoka, Chofu-shi, Tokyo 182-8585, Japan
| | - Kiyoshi Matsumoto
- IRT Research Initiative, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Ryuji Kawano
- Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei-shi, Tokyo 184-8588, Japan
| | - Isao Shimoyama
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
- IRT Research Initiative, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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Isozaki A, Kan T, Takahashi H, Matsumoto K, Shimoyama I. Out-of-plane actuation with a sub-micron initial gap for reconfigurable terahertz micro-electro-mechanical systems metamaterials. Opt Express 2015; 23:26243-26251. [PMID: 26480137 DOI: 10.1364/oe.23.026243] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We propose a reconfigurable terahertz (THz) metamaterial that can control the transmittance by out-of-plane actuation with changing the sub-micron gap distance between electrically coupled metamaterial elements. By using the out-of-plane actuation, it was possible to avoid contact between the coupled metamaterial elements across the small initial gap during the adjustment of the gap size. THz spectroscopy was performed during actuation, and the transmission dip frequency was confirmed to be tunable from 0.82 to 0.92 THz for one linear polarization state and from 0.80 to 0.91 THz for the other linear polarization; the two polarizations were orthogonal. The proposed approach will contribute to the development of tunable metamaterials based on structural deformations.
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Kan T, Isozaki A, Kanda N, Nemoto N, Konishi K, Takahashi H, Kuwata-Gonokami M, Matsumoto K, Shimoyama I. Enantiomeric switching of chiral metamaterial for terahertz polarization modulation employing vertically deformable MEMS spirals. Nat Commun 2015; 6:8422. [PMID: 26423346 PMCID: PMC4600721 DOI: 10.1038/ncomms9422] [Citation(s) in RCA: 178] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 08/19/2015] [Indexed: 11/22/2022] Open
Abstract
Active modulation of the polarization states of terahertz light is indispensable for polarization-sensitive spectroscopy, having important applications such as non-contact Hall measurements, vibrational circular dichroism measurements and anisotropy imaging. In the terahertz region, the lack of a polarization modulator similar to a photoelastic modulator in the visible range hampers expansion of such spectroscopy. A terahertz chiral metamaterial has a huge optical activity unavailable in nature; nevertheless, its modulation is still challenging. Here we demonstrate a handedness-switchable chiral metamaterial for polarization modulation employing vertically deformable Micro Electro Mechanical Systems. Vertical deformation of a planar spiral by a pneumatic force creates a three-dimensional spiral. Enantiomeric switching is realized by selecting the deformation direction, where the polarity of the optical activity is altered while maintaining the spectral shape. A polarization rotation as high as 28° is experimentally observed, thus providing a practical and compact polarization modulator for the terahertz range.
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Affiliation(s)
- Tetsuo Kan
- Department of Mechano-Informatics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Akihiro Isozaki
- IRT Research Initiative, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Natsuki Kanda
- Extreme Photonics Research Group, RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako 351-0198, Japan
- Photon Science Center, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Natsuki Nemoto
- Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Kuniaki Konishi
- Institute for Photon Science and Technology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Hidetoshi Takahashi
- Department of Mechano-Informatics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Makoto Kuwata-Gonokami
- Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Kiyoshi Matsumoto
- IRT Research Initiative, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Isao Shimoyama
- Department of Mechano-Informatics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
- IRT Research Initiative, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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Honda M, Baba Y, Shimoyama I, Sekiguchi T. A fluorescence XAFS measurement instrument in the soft X-ray region toward observation under operando conditions. Rev Sci Instrum 2015; 86:035103. [PMID: 25832271 DOI: 10.1063/1.4913653] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
X-ray absorption fine structure (XAFS) measurements are widely used for the analysis of electronic structure. Generally, XAFS in the soft X-ray region is measured under vacuum, but chemical structures under vacuum are typically different from those under operando conditions, where chemical species exhibit their function. Here, we developed an XAFS measurement instrument, as a step toward operando fluorescent, which yields XAFS measurement using synchrotron radiation in the soft X-ray region. We applied this method to analyze the local electronic structure of the sulfur atoms in L-cysteine in different pH solutions. In water at pH 7, the hydrogen atom does not dissociate from the thiol (-SH) group in L-cysteine, which forms a structure surrounded by and interacting with water molecules. The XAFS spectrum of L-cysteine in solution was altered by changing the pH. At pH 9, the hydrogen atom dissociated and a thiolate anion was formed. Although the -SH group was oxidized to SO4 (2-) when L-cysteine was adsorbed on a metal surface and dried, no oxidation was observed in solution. This may be because the water molecules were densely packed and protected the -SH group from oxidation. Our results show that this instrument aimed toward operando fluorescence XAFS measurements in the soft X-ray region is useful for structural analysis of sulfur atoms in organic molecules in air and in solution. The instrument will be applied to the structural analysis of materials containing elements that have absorption edges in soft X-ray region, such as phosphorus and alkali metals (potassium and cesium). It will be also particularly useful for the analysis of samples that are difficult to handle under vacuum and materials that have specific functions in solution.
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Affiliation(s)
- M Honda
- Quantum Beam Science Center, Japan Atomic Energy Agency (JAEA), 2-4 Shirakata-Shirane, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan
| | - Y Baba
- Quantum Beam Science Center, Japan Atomic Energy Agency (JAEA), 2-4 Shirakata-Shirane, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan
| | - I Shimoyama
- Quantum Beam Science Center, Japan Atomic Energy Agency (JAEA), 2-4 Shirakata-Shirane, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan
| | - T Sekiguchi
- Quantum Beam Science Center, Japan Atomic Energy Agency (JAEA), 2-4 Shirakata-Shirane, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan
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Baba Y, Shimoyama I, Hirao N, Sekiguchi T. Structures of quasi-freestanding ultra-thin silicon films deposited on chemically inert surfaces. Chem Phys 2014. [DOI: 10.1016/j.chemphys.2014.09.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Isozaki A, Kan T, Ajiki Y, Matsumoto K, Shimoyama I. Measurement method for light transmittance of layered metamaterials. Opt Lett 2013; 38:1811-1813. [PMID: 23722752 DOI: 10.1364/ol.38.001811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We propose a method to measure light transmittance of layered metamaterials by placing the metamaterials directly on a Si photodiode. Our measurement method enables the direct detection of transmitted light that appears as an evanescent wave in natural materials. Here, we report the transmittance measurements of a typical metamaterial using this method. The metamaterial was composed of Ag/Al(2)O(3) layers and was fabricated by direct evaporation on the Si photodiode. The measured transmittance agrees with the simulated transmittance. Our results confirmed that this measurement method can determine the transmittance properties of metamaterials and that it is applicable to other types of metamaterials.
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Affiliation(s)
- Akihiro Isozaki
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan. ‑tokyo.ac.jp
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22
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Yoo K, Takei Y, Kim S, Chiashi S, Maruyama S, Matsumoto K, Shimoyama I. Direct physical exfoliation of few-layer graphene from graphite grown on a nickel foil using polydimethylsiloxane with tunable elasticity and adhesion. Nanotechnology 2013; 24:205302. [PMID: 23598441 DOI: 10.1088/0957-4484/24/20/205302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We firstly introduce a facile method for the site-specific direct physical exfoliation of few-layer graphene sheets from cheap and easily enlargeable graphite grown on a Ni foil using an optimized polydimethylsiloxane (PDMS) stamp. By decreasing the PDMS cross-linking time, the PDMS elasticity is reduced to ∼52 kPa, similar to that of a typical gel. As a result of this process, the PDMS becomes more flexible yet remains in a handleable state as a stamp. Furthermore, the PDMS adhesion to a graphite/Ni surface, as measured by the peel strength, increases to ∼5.1 N m⁻¹, which is approximately 17 times greater than that of typical PDMS. These optimized properties allow the PDMS stamp to have improved contact with the graphite/Ni surface, including the graphite wrinkles. This process is verified, and changes in surface morphology are observed using a 3D laser scanning microscope. Under conformal contact, the optimized PDMS stamp demonstrates the site-specific direct physical exfoliation of few-layer graphene sheets including mono- and bi-layer graphene sheets from the graphite/Ni substrate without the use of special equipment, conditions or chemicals. The number of layers of the exfoliated graphene and its high quality are revealed by the measured Raman spectroscopy. The exfoliation method using tunable elasticity and adhesion of the PDMS stamp can be used not only for cost-effective mass production of defect-less few-layer graphene from the graphite substrate for micro/nano device arrays but also for nano-contact printing of various structures, devices and cells.
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Affiliation(s)
- Kwanghyun Yoo
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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Kan T, Aoki H, Binh-Khiem N, Matsumoto K, Shimoyama I. Ratiometric optical temperature sensor using two fluorescent dyes dissolved in an ionic liquid encapsulated by Parylene film. Sensors (Basel) 2013; 13:4138-45. [PMID: 23535716 PMCID: PMC3673075 DOI: 10.3390/s130404138] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2013] [Revised: 03/21/2013] [Accepted: 03/24/2013] [Indexed: 11/16/2022]
Abstract
A temperature sensor that uses temperature-sensitive fluorescent dyes is developed. The droplet sensor has a diameter of 40 μm and uses 1 g/L of Rhodamine B (RhB) and 0.5 g/L of Rhodamine 110 (Rh110), which are fluorescent dyes that are dissolved in an ionic liquid (1-ethyl-3-methylimidazolium ethyl sulfate) to function as temperature indicators. This ionic liquid is encapsulated using vacuum Parylene film deposition (which is known as the Parylene-on-liquid-deposition (PoLD) method). The droplet is sealed by the chemically stable and impermeable Parylene film, which prevents the dye from interacting with the molecules in the solution and keeps the volume and concentration of the fluorescent material fixed. The two fluorescent dyes enable the temperature to be measured ratiometrically such that the droplet sensor can be used in various applications, such as the wireless temperature measurement of microregions. The sensor can measure the temperature of such microregions with an accuracy of 1.9 °C, a precision of 3.7 °C, and a fluorescence intensity change sensitivity of 1.0%/K. The sensor can measure temperatures at different sensor depths in water, ranging from 0 to 850 μm. The droplet sensor is fabricated using microelectromechanical system (MEMS) technology and is highly applicable to lab-on-a-chip devices.
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Affiliation(s)
- Tetsuo Kan
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, 113-8656 Tokyo, Japan.
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Inaba A, Takei Y, Kan T, Matsumoto K, Shimoyama I. Electrochemical impedance measurement of a carbon nanotube probe electrode. Nanotechnology 2012; 23:485302. [PMID: 23124171 DOI: 10.1088/0957-4484/23/48/485302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We measured and analyzed the electrochemical impedance of carbon nanotube (CNT) probe electrodes fabricated through the physical separation of insulated CNT bridges. The fabricated CNT electrodes were free-standing CNTs that were completely covered with an insulator, except for their tips. Typical dimensions of the nanoelectrodes were 1-10 nm in CNT diameter, 80-300 nm in insulator diameter, 0.5-4 μm in exposed CNT length and 1-10 μm in probe length. The electrochemical impedance at frequencies ranging from 40 Hz to 1 MHz was measured in physiological saline. The measured impedance of the CNT electrode was constant at 32 MΩ at frequencies below 1 kHz and was inversely proportional to frequency at frequencies above 10 kHz. By means of comparison with the parasitic capacitive impedance of the insulator membrane, we confirmed that the electrode was sufficiently insulated such that the measured constant impedance was given by the exposed CNT tip. Consequently, we can use the CNT electrode for highly localized electrochemical impedance measurements below 1 kHz. Considering an equivalent circuit and the nanoscopic dimensions of the CNT electrode, we demonstrated that the constant impedance was governed by diffusion impedance, whereas the solution resistance, charge-transfer resistance and double-layer capacitance were negligible.
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Affiliation(s)
- Akira Inaba
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, The University of Tokyo, Tokyo, Japan.
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Takahashi H, Tanaka H, Matsumoto K, Shimoyama I. Differential pressure distribution measurement with an MEMS sensor on a free-flying butterfly wing. Bioinspir Biomim 2012; 7:036020. [PMID: 22711175 DOI: 10.1088/1748-3182/7/3/036020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
An insect can perform various flight maneuvers. However, the aerodynamic force generated by real insect wings during free flight has never been measured directly. In this study, we present the direct measurement of the four points of the differential pressures acting on the wing surface of a flying insect. A small-scale differential pressure sensor of 1.0 mm × 1.0 mm × 0.3 mm in size was developed using microelectromechanical systems (MEMS) and was attached to a butterfly wing. Total weight of the sensor chip and the flexible electrode on the wing was 4.5 mg, which was less than 10% of the wing weight. Four points on the wing were chosen as measurement points, and one sensor chip was attached in each flight experiment. During takeoff, the wing's flapping motion induced a periodic and symmetric differential pressure between upstroke and downstroke. The average absolute value of the local differential pressure differed significantly with the location: 7.4 Pa at the forewing tip, 5.5 Pa at the forewing center, 2.1 Pa at the forewing root and 2.1 Pa at the hindwing center. The instantaneous pressure at the forewing tip reached 10 Pa, which was ten times larger than wing loading of the butterfly.
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Affiliation(s)
- Hidetoshi Takahashi
- Information and Robot Technology Research Initiative, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan.
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Kan T, Matsumoto K, Shimoyama I. Optical measurement of directional strain by scattering from nano-disk pairs aligned on an elastomer. Nanotechnology 2012; 23:315201. [PMID: 22796757 DOI: 10.1088/0957-4484/23/31/315201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We propose a strain measurement method utilizing light scattered by a pair of nano-disks onto an elastomer sheet. Such nanoparticle pairs exhibit a scattering spectrum that is dependent on the gap distance and the incident light polarization. We utilized this behavior by forming nano-disk pairs with a diameter of 105 nm and a gap of 20-50 nm on a polydimethylsiloxane (PDMS) sheet so that the gap could be altered with strain. The axial direction of the nano-disk pair could be identified by finding the peak wavelength maximum while rotating the polarization angle. Under tensile strain, the peak wavelength decreased from 674 nm at a strain of 0% to 637 nm at a strain of 9.5%, with a peak-shift sensitivity of - 3.4 nm/% strain. Under compression strain, the peak wavelength increased from 681 nm at a strain of 0% to 705 nm at a strain of - 3.8%, and the peak-shift sensitivity was - 16 nm/% strain for strains of 0 to - 1%. These experimentally determined peak scattering wavelength positions and peak-shift directions are consistent with the simulation results. This method offers wireless measurements of in situ strain on a nanometric scale.
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Affiliation(s)
- Tetsuo Kan
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
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Affiliation(s)
- Tadashi Komatsu
- a Research and Development Center, Toshiba Corp., Kawasaki 210, Japan
| | | | - Shoichi Kura
- c Research and Development Center, Toshiba Corp., Kawasaki 210, Japan
| | - Hirofumi Miura
- d Faculty of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113, Japan
| | - Isao Shimoyama
- e Faculty of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113, Japan
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Affiliation(s)
- Yong Kwun Lee
- a Department of Mechano-Informatics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8356, Japan
| | - Isao Shimoyama
- b Department of Mechano-Informatics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8356, Japan
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Affiliation(s)
- Takashi Yasuda
- a Department of Mechano-Informatics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113, Japan
| | - Isao Shimoyama
- b Department of Mechano-Informatics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113, Japan
| | - Hirofumi Miura
- c Department of Mechano-Informatics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113, Japan
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Affiliation(s)
- Norihisa Miki
- a Mechano-Informatics, Faculty of Engineering, University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Isao Shimoyama
- b Mechano-Informatics, Faculty of Engineering, University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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Affiliation(s)
- Jun Miura
- a Mechanical Engineering for Computer-Controlled Machinery, Osaka University, Suita, Osaka 565, Japan
| | - Isao Shimoyama
- b Mechano-Informatics, University of Tokyo, Hongo, Tokyo 113, Japan
| | - Hirofumi Miura
- c Mechano-Informatics, University of Tokyo, Hongo, Tokyo 113, Japan
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Abstract
We found that liquid droplets encapsulated by Parylene deposited directly on a liquid surface deformed toward spherical shapes during Parylene deposition. This deformation suggested that the film stress was tensile. We calculated the film stress of such Parylene films by studying the surface mean curvature of the droplet shape and found the film stress measured about 0.7-0.9 MPa tensile. This film stress is of opposite type to that of as-deposited Parylene films deposited on solid substrates, which was compressive. This difference might indicate a profound change of the Parylene polymer due to the use of liquid surface as deposition substrate. The tensile film stress and its effect on the droplet shape also have implications in the fabrication and operation of Parylene microdevices that have encapsulated liquid structures such as microlens or micropumps.
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Affiliation(s)
- Binh-Khiem Nguyen
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, the University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo 113-8656, Japan.
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Kasagi Y, Shimoyama I, Okamoto R, Yoshida S. P1-5 Depth-dependent changes in stereoscopic visual evoked potentials by dynamic random dot stereograms. Clin Neurophysiol 2010. [DOI: 10.1016/s1388-2457(10)60418-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Higuchi Y, Nagano O, Aoyagi K, Uchiyama T, Shimoyama I, Kuwabara S, Saeki N. P5-21 Effects of chronic subthalamic stimulation on electroencephalography in Parkinson's disease. Clin Neurophysiol 2010. [DOI: 10.1016/s1388-2457(10)60543-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Yamashita K, Shimoyama I, Kasagi Y, Matsushiro N, Okamoto R, Yoshizaki K, Yoshida A, Hayashi F. P8-9 Auditory delayed feedback and learning: near infrared spectroscopy on the forehead. Clin Neurophysiol 2010. [DOI: 10.1016/s1388-2457(10)60612-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Okamoto R, Shimoyama I, Kasagi Y, Nakazawa K, Asano Y, Yamashita K, Shimada H. P1-2 Visual evoked potentials for convex or concave stereoscopic vision. Clin Neurophysiol 2010. [DOI: 10.1016/s1388-2457(10)60415-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Shimoyama I, Higuchi Y, Aoyagi K, Mamada K, Nagano O, Iwagami I, Uchiyama T, Saeki N, Kuwabara S. P31-12 Coherence of electroencephalograms on deep brain stimulation for parkinsonism. Clin Neurophysiol 2010. [DOI: 10.1016/s1388-2457(10)61179-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Shimoyama I, Shimada H, Odaka K, Asano Y, Saeki N, Kuwahara S, Shimizu R, Fukutake T. P37-1 Quantitative analysis for drawing a Necker cube. Clin Neurophysiol 2010. [DOI: 10.1016/s1388-2457(10)61318-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Ikawa N, Shimoyama I. P19-4 An application of 40-Hz auditory steady state response for objective audiometry test. Clin Neurophysiol 2010. [DOI: 10.1016/s1388-2457(10)60882-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Takahashi H, Aoyama Y, Ohsawa K, Tanaka H, Iwase E, Matsumoto K, Shimoyama I. Differential pressure measurement using a free-flying insect-like ornithopter with an MEMS sensor. Bioinspir Biomim 2010; 5:036005. [PMID: 20710069 DOI: 10.1088/1748-3182/5/3/036005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
This paper presents direct measurements of the aerodynamic forces on the wing of a free-flying, insect-like ornithopter that was modeled on a hawk moth (Manduca sexta). A micro differential pressure sensor was fabricated with micro electro mechanical systems (MEMS) technology and attached to the wing of the ornithopter. The sensor chip was less than 0.1% of the wing area. The mass of the sensor chip was 2.0 mg, which was less than 1% of the wing mass. Thus, the sensor was both small and light in comparison with the wing, resulting in a measurement system that had a minimal impact on the aerodynamics of the wing. With this sensor, the 'pressure coefficient' of the ornithopter wing was measured during both steady airflow and actual free flight. The maximum pressure coefficient observed for steady airflow conditions was 1.4 at an angle of attack of 30 degrees . In flapping flight, the coefficient was around 2.0 for angles of attack that ranged from 25 degrees to 40 degrees . Therefore, a larger aerodynamic force was generated during the downstroke in free flight compared to steady airflow conditions.
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Affiliation(s)
- Hidetoshi Takahashi
- Department of Mechano-Informatics, The University of Tokyo, Bunkyo-ku, Japan
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Abstract
Unlike other flying insects, the wing motion of swallowtail butterflies is basically limited to flapping because their fore wings partly overlap their hind wings, structurally restricting the feathering needed for active control of aerodynamic force. Hence, it can be hypothesized that the flight of swallowtail butterflies is realized with simple flapping, requiring little feedback control of the feathering angle. To verify this hypothesis, we fabricated an artificial butterfly mimicking the wing motion and wing shape of a swallowtail butterfly and analyzed its flights using images taken with a high-speed video camera. The results demonstrated that stable forward flight could be realized without active feathering or feedback control of the wing motion. During the flights, the artificial butterfly's body moved up and down passively in synchronization with the flapping, and the artificial butterfly followed an undulating flight trajectory like an actual swallowtail butterfly. Without feedback control of the wing motion, the body movement is directly affected by change of aerodynamic force due to the wing deformation; the degree of deformation was determined by the wing venation. Unlike a veinless wing, a mimic wing with veins generated a much higher lift coefficient during the flapping flight than in a steady flow due to the large body motion.
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Affiliation(s)
- Hiroto Tanaka
- School of Engineering and Applied Sciences, Harvard University, 60 Oxford Street, Cambridge, MA 02138, USA
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Takei A, Matsumoto K, Shimoyama I. Capillary torque caused by a liquid droplet sandwiched between two plates. Langmuir 2010; 26:2497-2504. [PMID: 20000407 DOI: 10.1021/la902779g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Capillary force makes a liquid droplet's surface have the minimum area. If the droplet is sandwiched between two plates, it exerts capillary force on the plates. The magnitude of the force depends on the shape of the sandwiched droplet, which is in turn determined by the shape of the plates and the volume of the liquid. The liquid's shape, however, is hard to determine analytically. In this paper, the torque caused by a droplet sandwiched between two noncircular plates is experimentally and theoretically analyzed. We patterned a magnetic material on the surface of the plates and used it to apply a magnetic force to the plates. The torque on the plates was measured. The torque caused by capillary force was calculated by observing the equilibrium between the capillary force and magnetic force. We obtained approximate theoretical solutions for the liquid's shape and torque and verified that they were in accordance with the experimental results. The experimental and theoretical results presented in this paper are useful for designing microdevices or self-assemblies actuated by capillary force.
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Affiliation(s)
- Atsushi Takei
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan.
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Takamatsu S, Takano H, Nguyen BK, Takahata T, Iwase E, Matsumoto K, Shimoyama I. Liquid-phase packaging of a glucose oxidase solution with parylene direct encapsulation and an ultraviolet curing adhesive cover for glucose sensors. Sensors (Basel) 2010; 10:5888-98. [PMID: 22219693 PMCID: PMC3247738 DOI: 10.3390/s100605888] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Revised: 05/15/2010] [Accepted: 05/30/2010] [Indexed: 11/24/2022]
Abstract
We have developed a package for disposable glucose sensor chips using Parylene encapsulation of a glucose oxidase solution in the liquid phase and a cover structure made of an ultraviolet (UV) curable adhesive. Parylene was directly deposited onto a small volume (1 μL) of glucose oxidase solution through chemical vapor deposition. The cover and reaction chamber were constructed on Parylene film using a UV-curable adhesive and photolithography. The package was processed at room temperature to avoid denaturation of the glucose oxidase. The glucose oxidase solution was encapsulated and unsealed. Glucose sensing was demonstrated using standard amperometric detection at glucose concentrations between 0.1 and 100 mM, which covers the glucose concentration range of diabetic patients. Our proposed Parylene encapsulation and UV-adhesive cover form a liquid phase glucose-oxidase package that has the advantages of room temperature processing and direct liquid encapsulation of a small volume solution without use of conventional solidifying chemicals.
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Kuwana K, Dohi T, Hashimoto Y, Matsumoto K, Shimoyama I. Implantable telemetry capsule for monitoring arterial oxygen saturation and heartbeat. Annu Int Conf IEEE Eng Med Biol Soc 2009; 2008:3204-7. [PMID: 19163388 DOI: 10.1109/iembs.2008.4649885] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In this study, we have developed an implantable telemetry capsule for monitoring heartbeat. The capsule has three main functions, monitoring vital signs, transmitting the vital signs, and receiving energy for driving the capsule without wires. We used two wavelengths of LEDs and a photodiode sensitive to the two wavelengths for heartbeat sensor. The arterial oxygen saturation is calculated from the amplitude of the heartbeat signal. We fabricated an FM transmitter whose carrier frequency was 80 MHz. Though the GHz range frequency is generally used in transmission, the attenuation in the human body is large. The size of a common linear antenna is about a quarter of its operating wavelength. We employed a coil-based antenna which can reduce size below the quarter of the wavelength. We fabricated a miniaturized transmitter with the coil-based antenna at lower frequency. Our capsule was driven intermittently. We used a rechargeable battery. When the battery ran down, the battery was charged by wireless using the induced electromotive force. This means that the capsule is capable of monitoring vital signs over the long term. We measured the heartbeat from the middle finger of hand in a water tank as a model of a human body.
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Affiliation(s)
- K Kuwana
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, the University of Tokyo, Tokyo, Japan.
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Takamatsu S, Matsumoto K, Shimoyama I. Mechanically flexible and expandable display with conductive-polymer-coated nylon fabric. ACTA ACUST UNITED AC 2008. [DOI: 10.1109/memsys.2008.4443612] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Yoshida S, Nakazawa K, Shimizu E, Shimoyama I. Anticipatory postural adjustments modify the movement-related potentials of upper extremity voluntary movement. Gait Posture 2008; 27:97-102. [PMID: 17408954 DOI: 10.1016/j.gaitpost.2007.02.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2006] [Accepted: 02/25/2007] [Indexed: 02/02/2023]
Abstract
To elucidate the effect on movement-related potentials (MRPs) of anticipatory postural adjustments (APAs) accompanied by voluntary focal movement, we examined the MRPs of shoulder flexion movement under standing and sitting postural conditions in 12 normal subjects. MRPs were evaluated based on three components: readiness potential (RP), motor potential (MP), and movement-monitoring potential. APAs were observed in the activities of postural muscles including the biceps femoris and erector spinae muscles only under standing conditions. The amplitudes of the three MRP components were larger under standing conditions than under sitting conditions for all recorded electrode positions, and the RP and MP amplitudes at the vertex position, which lies over the supplementary motor area (SMA), showed a prominent increase under standing conditions with the highest statistical significance. These results suggest that a recruited neural process of the cortical area including the SMA may be necessary to generate voluntary movement accompanied by APA.
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Affiliation(s)
- S Yoshida
- Department of Integrative Neurophysiology, Graduate School of Medicine, Chiba University, Chiba-Shi, Chiba, Japan.
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Affiliation(s)
- Hiroaki Onoe
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, The University of Tokyo, Tokyo, Japan. )
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Kan T, Matsumoto K, Shimoyama I. Piezoresistor-equipped fluorescence-based cantilever probe for near-field scanning. Rev Sci Instrum 2007; 78:083106. [PMID: 17764312 DOI: 10.1063/1.2774824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Scanning near-field optical microscopes (SNOMs) with fluorescence-based probes are promising tools for evaluating the optical characteristics of nanoaperture devices used for biological investigations, and this article reports on the development of a microfabricated fluorescence-based SNOM probe with a piezoresistor. The piezoresistor was built into a two-legged root of a 160-microm-long cantilever. To improve the displacement sensitivity of the cantilever, the piezoresistor's doped area was shallowly formed on the cantilever surface. A fluorescent bead, 500 nm in diameter, was attached to the bottom of the cantilever end as a light-intensity-sensitive material in the visible-light range. The surface of the scanned sample was simply detected by the probe's end being displaced by contact with the sample. Measuring displacements piezoresistively is advantageous because it eliminates the noise arising from the use of the optical-lever method and is free of any disturbance in the absorption or the emission spectrum of the fluorescent material at the probe tip. The displacement sensitivity was estimated to be 6.1 x 10(-6) nm(-1), and the minimum measurable displacement was small enough for near-field measurement. This probe enabled clear scanning images of the light field near a 300 x 300 nm(2) aperture to be obtained in the near-field region where the tip-sample distance is much shorter than the light wavelength. This scanning result indicates that the piezoresistive way of tip-sample distance regulation is effective for characterizing nanoaperture optical devices.
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Affiliation(s)
- Tetsuo Kan
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, The University of Tokyo, 7-3-1 Hongo, Tokyo, Japan
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Ono K, Shiba K, Nakazawa K, Shimoyama I. Synaptic origin of the respiratory-modulated activity of laryngeal motoneurons. Neuroscience 2006; 140:1079-88. [PMID: 16650611 DOI: 10.1016/j.neuroscience.2006.02.063] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2005] [Revised: 02/16/2006] [Accepted: 02/24/2006] [Indexed: 12/31/2022]
Abstract
To determine the synaptic source of the respiratory-related activity of laryngeal motoneurons, spike-triggered averaging of the membrane potentials of laryngeal motoneurons was conducted using spikes of respiratory neurons located between the Bötzinger complex and the rostral ventral respiratory group as triggers in decerebrate, paralyzed cats. We identified one excitatory and two inhibitory sources for inspiratory laryngeal motoneurons, and two inhibitory sources for expiratory laryngeal motoneurons. In inspiratory laryngeal motoneurons, monosynaptic excitatory postsynaptic potentials were evoked by spikes of inspiratory neurons with augmenting firing patterns, and monosynaptic inhibitory postsynaptic potentials (IPSPs) were evoked by spikes of expiratory neurons with decrementing firing patterns and by spikes of inspiratory neurons with decrementing firing patterns. In expiratory laryngeal motoneurons, monosynaptic IPSPs were evoked by spikes of inspiratory neurons with decrementing firing patterns and by spikes of expiratory neurons with augmenting firing patterns. We conclude that various synaptic inputs from respiratory neurons contribute to shaping the respiratory-related trajectory of membrane potential of laryngeal motoneurons.
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Affiliation(s)
- K Ono
- Department of Otolaryngology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba-shi, Chiba 260-8670, Japan
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