The Experts below are selected from a list of 252 Experts worldwide ranked by ideXlab platform

Bae Ho Park - One of the best experts on this subject based on the ideXlab platform.

  • selective measurement of calcium and sodium ion conductance using sub micropipette probes with ion filters
    Applied Physics Express, 2012
    Co-Authors: Xiaolong Deng, Tomohide Takami, Tomoji Kawai, Bae Ho Park
    Abstract:

    Selective ion currents in aqueous calcium chloride and sodium chloride solutions with concentrations of up to 1.0 M were observed with sub-Micropipettes in which poly(vinyl chloride) (PVC) films containing ionophores selectively filtered cations. Calcium bis[4-(1,1,3,3-tetramethylbutyl)phenyl] phosphate (HDOPP-Ca) and bis[(12-crown-4)methyl]-2-dodecyl-2-methylmalonate [bis(12-crown-4)] were used as the ionophores to filter calcium and sodium ions, respectively. The selective ion current was observed using a low-current detection system developed from scanning tunneling microscopy. The approximate linear relationship between the ion concentration and ion current suggests that the sub-micropipette probe can be used to detect the intracellular local concentration of a specific ion up to 1.0 M.

  • Separate Detection of Sodium and Potassium Ions with Sub-micropipette Probe
    Japanese Journal of Applied Physics, 2011
    Co-Authors: Tomohide Takami, Bae Ho Park, Tomoji Kawai
    Abstract:

    A novel method of detecting sodium and potassium ions separately with a sub-micropipette probe of approximately 100 nm inner diameter has been demonstrated. A poly(vinyl chloride) film containing crown ether ligands in sub-Micropipettes filtered the ions. Sodium ions were trapped with bis(12-crown-4), whereas potassium ions were trapped with bis(benzo-15-crown-5). Alternate and direct bias voltages were applied to the counter electrode in the sub-micropipette so that the local ion concentrations could be observed as current signals after conversion to milivolt output signals with our low-current detection system prepared for this study.

Masaru Kojima - One of the best experts on this subject based on the ideXlab platform.

  • Strategies of Stable Grasp and Accurate Release for Dual-finger Micromanipulator
    2018 International Symposium on Micro-NanoMechatronics and Human Science (MHS), 2018
    Co-Authors: Junnan Chen, Masaru Kojima, Qiang Huang, Toshio Fukuda, Tatsuo Arai
    Abstract:

    In microscale, adhesion force enables us to grasp targets with only one end-effector. However, due to the vibration of the driving unit and the environmental disturbance, losing target often happens during the grasp. The adhesion also makes releasing the targets from the end-effector difficult, and release accuracy cannot be guaranteed. In this paper, we proposed novel strategies of grasp and release for a dual-finger micromanipulator. The dual-finger micromanipulator includes two Micropipettes as the end-effectors. One micropipette is fixed and the other active micropipette is actuated by a piezo-driven 3-DOF parallel mechanism. Tips of the Micropipettes are heated to form spherical tips, then the tips are grinded to form hemispherical shapes. The big flat surfaces of the hemispherical end-effectors can increase the success rate of the grasp and avoid the target lose. In the release strategy, the hemispherical tip of the active micropipette is coated with gel to keep the target always sticking on the tip of active micropipette. Then, the active pipette is controlled to vibrate, and release the target adhered on its tip.

  • Stable Grasp and Accurate Release of Microbeads by a Two-finger Microhand
    2018 IEEE International Conference on Mechatronics and Automation (ICMA), 2018
    Co-Authors: Junnan Chen, Tatsuo Arai, Pengyun Li, Xiaoqing Tang, Masaru Kojima
    Abstract:

    In microscale, the adhesion force between the object and the end-effector becomes one of the main forces affecting the micromanipulation. During operating the micro objects, adhesion force enables us pick up with only one end-effector, but high success rate and stable grasp cannot be guaranteed. Besides, the adhesion force causes the difficulty of release, and release accuracy of the existing release method is not satisfying. To solve these two key problems in micromanipulation, we proposed an optimized two-finger microhand system to achieve both stable grasp and accurate release. One micropipette mounted on a parallel compliant mechanism can be positioned in a 3D space actuated by three piezo actuators, and another micropipette is fixed. The tips of the two Micropipettes are heated to form spheroids at the end, and then grinded to achieve hemispherical end-effectors for high success rate stable grasp. The motorized end-effector is coated with the gel to keep the object always stick on it when open the two finger. Then this end-effector is controlled to vibrate to overcome the adhesion force between the end-effector and the object. Experiments of grasp microbeads have been carried out to demonstrate the stable grasp with hemispherical end-effectors. The microbeads have also been released with different vibrate frequencies and amplitudes to quantify its release accuracy under different conditions. Finally, with the proposed grasp and release methods, we apply microbeads to assemble a line.

Tomoji Kawai - One of the best experts on this subject based on the ideXlab platform.

  • selective measurement of calcium and sodium ion conductance using sub micropipette probes with ion filters
    Applied Physics Express, 2012
    Co-Authors: Xiaolong Deng, Tomohide Takami, Tomoji Kawai, Bae Ho Park
    Abstract:

    Selective ion currents in aqueous calcium chloride and sodium chloride solutions with concentrations of up to 1.0 M were observed with sub-Micropipettes in which poly(vinyl chloride) (PVC) films containing ionophores selectively filtered cations. Calcium bis[4-(1,1,3,3-tetramethylbutyl)phenyl] phosphate (HDOPP-Ca) and bis[(12-crown-4)methyl]-2-dodecyl-2-methylmalonate [bis(12-crown-4)] were used as the ionophores to filter calcium and sodium ions, respectively. The selective ion current was observed using a low-current detection system developed from scanning tunneling microscopy. The approximate linear relationship between the ion concentration and ion current suggests that the sub-micropipette probe can be used to detect the intracellular local concentration of a specific ion up to 1.0 M.

  • Separate Detection of Sodium and Potassium Ions with Sub-micropipette Probe
    Japanese Journal of Applied Physics, 2011
    Co-Authors: Tomohide Takami, Bae Ho Park, Tomoji Kawai
    Abstract:

    A novel method of detecting sodium and potassium ions separately with a sub-micropipette probe of approximately 100 nm inner diameter has been demonstrated. A poly(vinyl chloride) film containing crown ether ligands in sub-Micropipettes filtered the ions. Sodium ions were trapped with bis(12-crown-4), whereas potassium ions were trapped with bis(benzo-15-crown-5). Alternate and direct bias voltages were applied to the counter electrode in the sub-micropipette so that the local ion concentrations could be observed as current signals after conversion to milivolt output signals with our low-current detection system prepared for this study.

Tomohide Takami - One of the best experts on this subject based on the ideXlab platform.

  • selective measurement of calcium and sodium ion conductance using sub micropipette probes with ion filters
    Applied Physics Express, 2012
    Co-Authors: Xiaolong Deng, Tomohide Takami, Tomoji Kawai, Bae Ho Park
    Abstract:

    Selective ion currents in aqueous calcium chloride and sodium chloride solutions with concentrations of up to 1.0 M were observed with sub-Micropipettes in which poly(vinyl chloride) (PVC) films containing ionophores selectively filtered cations. Calcium bis[4-(1,1,3,3-tetramethylbutyl)phenyl] phosphate (HDOPP-Ca) and bis[(12-crown-4)methyl]-2-dodecyl-2-methylmalonate [bis(12-crown-4)] were used as the ionophores to filter calcium and sodium ions, respectively. The selective ion current was observed using a low-current detection system developed from scanning tunneling microscopy. The approximate linear relationship between the ion concentration and ion current suggests that the sub-micropipette probe can be used to detect the intracellular local concentration of a specific ion up to 1.0 M.

  • Separate Detection of Sodium and Potassium Ions with Sub-micropipette Probe
    Japanese Journal of Applied Physics, 2011
    Co-Authors: Tomohide Takami, Bae Ho Park, Tomoji Kawai
    Abstract:

    A novel method of detecting sodium and potassium ions separately with a sub-micropipette probe of approximately 100 nm inner diameter has been demonstrated. A poly(vinyl chloride) film containing crown ether ligands in sub-Micropipettes filtered the ions. Sodium ions were trapped with bis(12-crown-4), whereas potassium ions were trapped with bis(benzo-15-crown-5). Alternate and direct bias voltages were applied to the counter electrode in the sub-micropipette so that the local ion concentrations could be observed as current signals after conversion to milivolt output signals with our low-current detection system prepared for this study.

T. Moriizumi - One of the best experts on this subject based on the ideXlab platform.

  • Development of a new geometrical form of micropipette: electrical characteristics and an application as a potassium ion selective electrode
    IEEE Transactions on Biomedical Engineering, 1992
    Co-Authors: P.j. Abatti, T. Moriizumi
    Abstract:

    Using a mix of thermal and anodic bonding together with microlithographic techniques, the safe transference of a Si/sub 3/N/sub 4/ film with a pore (diameter down to 1 mu m) to a glass tube tip (external diameter 800 mu m) was accomplished, yielding a new geometrical form of micropipette. Compared with conventional glass Micropipettes the device has shown lower resistance, more stable capacitance (independent of the tip immersion depth), tip potential closer to that of a salt bridge, and a simplified filling process. Using this device as a potassium ion selective electrode (ISE), a faster response time ISE was achieved. These features indicate that the new device can advantageously substitute the conventional glass Micropipettes when cell impalement is not required.