The Experts below are selected from a list of 50076 Experts worldwide ranked by ideXlab platform
Kenzo Kurihara - One of the best experts on this subject based on the ideXlab platform.
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inositol 1 4 5 trisphosphate induces responses in receptor neurons in rat vomeronasal sensory slices
Chemical Senses, 1997Co-Authors: Kouhei Inamura, Makoto Kashiwayanagi, Kenzo KuriharaAbstract:: Using the whole-cell mode of the patch-Clamp technique, we recorded action potentials, Voltage-activated cationic currents and putative second messenger-activated currents in receptor neurons in the vomeronasal sensory epithelium of female rats. The resting membrane potential and input resistance were -45.5 +/- 2.5 mV (mean +/- SEM, n = 39) and 1.5 +/- 0.2 G omega (mean +/- SEM, n = 37). Current injection of 1-3 pA induced overshooting action potentials. The firing frequency increased with increasing current injections linearly from 1 to 10 pA and reached a plateau at 30 pA, suggesting that rat vomeronasal receptor neurons sensitively elicit action potentials in response to a small receptor potential. Under Voltage Clamp, Voltage-dependent Na+ inward current, inward Ca2+ current, sustained outward K+ current and Ca-(2+)-activated K(+)-current were identified. Dialysis of D-inositol-1,4,5-trisphosphate (D-IP3) induced inward currents with an increase in membrane conductance in approximately 54% of the cells and inward current fluctuations in 15% of the cell. L-IP3 also induced inward currents and current fluctuations in 53 and 13% of the cells respectively. The mean amplitude of inward currents induced by 100 microM D-IP3 and L-IP3 were 84.6 +/- 14.0 pA (SEM, n = 82) and 66.1 +/- 9.4 pA (SEM, n = 100) respectively. The IP3-induced responses were blocked by elimination of Na+ and Ca2+ in the external solution or application of 10 microM ruthenium red. The present study suggested that IP3-mediated transduction pathways exist in rat vomeronasal receptor neurons.
Donhee Ham - One of the best experts on this subject based on the ideXlab platform.
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the design of a cmos nanoelectrode array with 4096 current Clamp Voltage Clamp amplifiers for intracellular recording stimulation of mammalian neurons
IEEE Journal of Solid-state Circuits, 2020Co-Authors: Jeffrey Abbott, Keith Krenek, Ling Qin, Youbin Kim, Rona S Gertner, Hongkun Park, Donhee HamAbstract:CMOS microelectrode arrays (MEAs) can record electrophysiological activities of a large number of neurons in parallel but only extracellularly with a low signal-to-noise ratio. Patch-Clamp electrodes can perform intracellular recording with a high signal-to-noise ratio but only from a few neurons in parallel. Recently, we have developed and reported a neuroelectronic interface that combines the parallelism of the CMOS MEA and the intracellular sensitivity of the patch Clamp. Here, we report the design and characterization of the CMOS integrated circuit (IC), a critical component of the neuroelectronic interface. Fabricated in 0.18- $\mu \text{m}$ technology, the IC features an array of 4096 platinum black (PtB) nanoelectrodes spaced at a 20- $\mu \text{m}$ pitch on its surface and contains 4096 active pixel circuits. Each active pixel circuit, consisting of a new switched-capacitor current injector—-capable of injecting from ±15 pA to ±0.7 $\mu \text{A}$ with a 5-pA resolution—-and an operational amplifier, is highly configurable. When configured into the current-Clamp mode, the pixel intracellularly records membrane potentials, including subthreshold activities with ~23- $\mu \text{V}_{\mathrm {rms}}$ input-referred noise while injecting a current for simultaneous stimulation. When configured into the Voltage-Clamp mode, the pixel becomes a switched-capacitor transimpedance amplifier with ~1-pArms input-referred noise and intracellularly records ion channel currents while applying a Voltage for simultaneous stimulation. Such Voltage-/current-Clamp intracellular recording/stimulation is a feat only previously possible with the patch-Clamp method. At the same time, as an array, the IC overcomes the lack of parallelism of the patch-Clamp method, measuring thousands of mammalian neurons in parallel, with full-frame intracellular recording/stimulation at 9.4 kHz.
S P Robb - One of the best experts on this subject based on the ideXlab platform.
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high Voltage Clamped igbt for automotive ignition applications
International Symposium on Power Semiconductor Devices and IC's, 1998Co-Authors: Z J Shen, S P RobbAbstract:A new field-limiting-ring (FLR) concept with variable ring widths is proposed for designing a high Voltage collector-gate Clamped IGBT. An IGBT based on the new concept has been designed and fabricated with a standard IGBT process flow to provide a Clamp Voltage of 620 volts. The new high Voltage Clamped IGBT is to be primarily used in automotive ignition applications.
Hideichi Shinkawa - One of the best experts on this subject based on the ideXlab platform.
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Developmental Expression of the Outer Hair Cell Motor Prestin in the Mouse
Journal of Membrane Biology, 2007Co-Authors: Takahisa Abe, Seiji Kakehata, Rei Kitani, Shin-ichiro Maruya, Dhasakumar Navaratnam, Joseph Santos-sacchi, Hideichi ShinkawaAbstract:The development of motor protein activity in the lateral membrane of the mouse outer hair cell (OHC) from postnatal day 5 (P5) to P18 was investigated under whole-cell Voltage Clamp. Voltage-dependent, nonlinear capacitance ( C _v), which represents the conformational fluctuations of the motor molecule, progressively increased during development. At P12, the onset of hearing in the mouse, C _v was about 70% of the mature level. C _v saturated at P18 when hearing shows full maturation. On the other hand, C _lin, which represents the membrane area of the OHC, showed a relatively small increase with development, reaching steady state at P10. This early maturation of linear capacitance is further supported by morphological estimates of surface area during development. These results, in light of recent prestin knockout experiments and our results with quantitative polymerase chain reaction, suggest that, rather than the incorporation of new motors into the lateral membrane after P10, molecular motors mature to augment nonlinear capacitance. Thus, current estimates of motor protein density based on charge movement may be exaggerated. A corresponding indicator of motor maturation, the motor’s operating Voltage midpoint, V _pkcm, tended to shift to depolarized potentials during postnatal development, although it was unstable prior to P10. However, after P14, V _pkcm reached a steady-state level near −67 m V , suggesting that intrinsic membrane tension or intracellular chloride, each of which can modulate V _pkcm, may mature at P14. These developmental data significantly alter our understanding of the cellular mechanisms that control cochlear amplification and provide a foundation for future analysis of genetic modifications of mouse auditory development.
K King - One of the best experts on this subject based on the ideXlab platform.
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cross regulation in flyback converters analytic model and solution
IEEE Transactions on Power Electronics, 2001Co-Authors: Chuanwen Ji, M Smith, K M Smedley, K KingAbstract:An analytical model for studying cross regulation among the multiple outputs of flyback converters is presented in this paper. Both the theoretical and experimental results show that the cross regulation can be improved by lowering the Clamp Voltage, which has not been previously reported. Many other factors, such as the leakage inductance in primary and secondary windings, the magnetizing inductance, and the air gap can also affect the cross regulation. Detailed analysis and test results are provided. Based on this model, a cost-effective passive energy regenerative Clamp is proposed that allows the Clamp Voltage to be much lower than that of traditional RC Clamps, thus improving the cross regulation and energy efficiency.