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Sample records for active gate driver

  1. Active gated imaging in driver assistance system

    Science.gov (United States)

    Grauer, Yoav

    2014-04-01

    In this paper, we shall present the active gated imaging system (AGIS) in relation to the automotive field. AGIS is based on a fast-gated camera and pulsed illuminator, synchronized in the time domain to record images of a certain range of interest. A dedicated gated CMOS imager sensor and near infra-red (NIR) pulsed laser illuminator, is presented in this paper to provide active gated technology. In recent years, we have developed these key components and learned the system parameters, which are most beneficial to nighttime (in all weather conditions) driving in terms of field of view, illumination profile, resolution, and processing power. We shall present our approach of a camera-based advanced driver assistance systems (ADAS) named BrightEye™, which makes use of the AGIS technology in the automotive field.

  2. Active gate driver for dv/dt control and active voltage clamping in an IGBT stack

    DEFF Research Database (Denmark)

    Rasmussen, Tonny Wederberg

    2005-01-01

    For high voltages converters stacks of IGBTs can be used if the static and dynamic voltage sharing among the IGBTs can be applied. dVCE/dt should also be controlled in order not to damage insulation material. This paper describes theory and measurements of an active gate driver for stacking IGBTs...

  3. An Integrated Gate Driver in 4H-SiC for Power Converter Applications

    Energy Technology Data Exchange (ETDEWEB)

    Ericson, Milton Nance [ORNL; Frank, Steven Shane [ORNL; Britton, Charles [Oak Ridge National Laboratory (ORNL); Janke, Devon D [ORNL; Ezell, N Dianne Bull [ORNL; Ryu, Sei_Hyung [Cree Semiconductor; Mantooth, Alan [University of Arkansas; Francis, Dr. Matt [University of Arkansas; Lanmichhane, Dr. Ranjan [University of Arkansas; Shepherd, Dr. Paul [University of Arkansas; Glover, Dr. Michael [University of Arkansas; Whitaker, Mr. Bret [APEI, Inc.; Cole, Mr. Zach [APEI, Inc.; Passmore, Mr. Brandon [APEI, Inc.; Mcnutt, Tyler [APEI, Inc.

    2014-01-01

    A gate driver fabricated in a 2-um 4H silicon carbide (SiC) process is presented. This process was optimized for vertical power MOSFET fabrication but accommodated integration of a few low-voltage device types including N-channel MOSFETs, resistors, and capacitors. The gate driver topology employed incorporates an input level translator, variable power connections, and separate power supply connectivity allowing selection of the output signal drive amplitude. The output stage utilizes a source follower pull-up device that is both overdriven and body source connected to improve rise time behavior. Full characterization of this design driving a SiC power MOSFET is presented including rise and fall times, propagation delays, and power consumption. All parameters were measured to elevated temperatures exceeding 300 C. Details of the custom test system hardware and software utilized for gate driver testing are also provided.

  4. A Novel Quadratic Buck-Boost DC-DC Converter without Floating Gate-Driver

    DEFF Research Database (Denmark)

    Mostaan, Ali; A. Gorji, Saman; N. Soltani, Mohsen

    2016-01-01

    for floating gate driver. In addition, the voltage stress of one of the switches is lower than the existing quadratic buck-boost converters. Performance of the analytical results is validated using both simulation in MATLAB/SIMULINK and experimental tests where the proposed converter is evaluated in both buck...

  5. A Novel Quadratic Buck-Boost DC-DC Converter without Floating Gate-Driver

    DEFF Research Database (Denmark)

    Mostaan, Ali; A. Gorji, Saman; N. Soltani, Mohsen

    2016-01-01

    for floating gate driver. In addition, the voltage stress of one of the switches is lower than the existing quadratic buck-boost converters. Performance of the analytical results is validated using both simulation in MATLAB/SIMULINK and experimental tests where the proposed converter is evaluated in both buck...

  6. A VHF Class E DC-DC Converter with Self-Oscillating Gate Driver

    DEFF Research Database (Denmark)

    Andersen, Toke Meyer; Christensen, Søren K.; Knott, Arnold

    2011-01-01

    This paper describes the analysis and design of a DC-DC converter topology which is operational at frequencies in the Very High Frequency (VHF) band ranging from 30 MHz − 300 MHz. The presented topology, which consists of a class E inverter, class E rectifier, and self-oscillating gate driver, is...

  7. Compact, Intelligent, Digitally Controlled IGBT Gate Drivers for a PEBB-Based ILC Marx Modulator

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, M.N.; Burkhart, C.; Olsen, J.J.; Macken, K.; /SLAC

    2010-06-07

    SLAC National Accelerator Laboratory has built and is currently operating a first generation prototype Marx klystron modulator to meet ILC specifications. Under development is a second generation prototype, aimed at improving overall performance, serviceability, and manufacturability as compared to its predecessor. It is designed around 32 cells, each operating at 3.75 kV and correcting for its own capacitor droop. Due to the uniqueness of this application, high voltage gate drivers needed to be developed for the main 6.5 kV and droop correction 1.7 kV IGBTs. The gate driver provides vital functions such as protection of the IGBT from over-voltage and over-current, detection of gate-emitter open and short circuit conditions, and monitoring of IGBT degradation (based on collector-emitter saturation voltage). Gate drive control, diagnostic processing capabilities, and communication are digitally implemented using an FPGA. This paper details the design of the gate driver circuitry, component selection, and construction layout. In addition, experimental results are included to illustrate the effectiveness of the protection circuit.

  8. A 200 C Universal Gate Driver Integrated Circuit for Extreme Environment Applications

    Energy Technology Data Exchange (ETDEWEB)

    Tolbert, Leon M [ORNL; Huque, Mohammad A [ORNL; Islam, Syed K [ORNL; Blalock, Benjamin J [ORNL

    2012-01-01

    High-temperature power converters (dc-dc, dc-ac, etc.) have enormous potential in extreme environment applications, including automotive, aerospace, geothermal, nuclear, and well logging. For successful realization of such high-temperature power conversion modules, the associated control electronics also need to perform at high temperature. This paper presents a silicon-on-insulator (SOI) based high-temperature gate driver integrated circuit (IC) incorporating an on-chip low-power temperature sensor and demonstrating an improved peak output current drive over our previously reported work. This driver IC has been primarily designed for automotive applications, where the underhood temperature can reach 200 C. This new gate driver prototype has been designed and implemented in a 0.8 {micro}m, 2-poly, and 3-metal bipolar CMOS-DMOS (Double-Diffused Metal-Oxide Semiconductor) on SOI process and has been successfully tested for up to 200 C ambient temperature driving a SiC MOSFET and a SiC normally-ON JFET. The salient feature of the proposed universal gate driver is its ability to drive power switches over a wide range of gate turn-ON voltages such as MOSFET (0 to 20 V), normally-OFF JFET (-7 to 3 V), and normally-ON JFET (-20 to 0 V). The measured peak output current capability of the driver is around 5 A and is thus capable of driving several power switches connected in parallel. An ultralow-power on-chip temperature supervisory circuit has also been integrated into the die to safeguard the driver circuit against excessive die temperature ({ge}220 C). This approach utilizes increased diode leakage current at higher temperature to monitor the die temperature. The power consumption of the proposed temperature sensor circuit is below 10 {micro}W for operating temperature up to 200 C.

  9. Diode-clamped multilevel converters with integrable gate-driver power-supply circuits

    OpenAIRE

    Busquets Monge, Sergio; Rocabert Delgado, Joan; Crébier, Jean-Christophe; Peracaula Roura, Joan

    2009-01-01

    International audience; Recent contributions in pulse width modulations (PWM) for multilevel diode-clamped converters enable the use of these converters with passive front-ends, any number of levels, and small dc-link capacitors. Highly compact converters designs based on these topologies can be envisioned. However, the design of the gate-driver power-supply for the multiple controlled semiconductor devices remains an important issue to be addressed. This paper focuses on the design of such c...

  10. SOI-Based High-Voltage, High-Temperature Integrated Circuit Gate Driver for SiC-Based Power FETs

    Energy Technology Data Exchange (ETDEWEB)

    Huque, Mohammad A [ORNL; Tolbert, Leon M [ORNL; Blalock, Benjamin [University of Tennessee, Knoxville (UTK); Islam, Syed K [University of Tennessee, Knoxville (UTK)

    2010-01-01

    Silicon carbide (SiC)-based field effect transistors (FETs) are gaining popularity as switching elements in power electronic circuits designed for high-temperature environments like hybrid electric vehicle, aircraft, well logging, geothermal power generation etc. Like any other power switches, SiC-based power devices also need gate driver circuits to interface them with the logic units. The placement of the gate driver circuit next to the power switch is optimal for minimizing system complexity. Successful operation of the gate driver circuit in a harsh environment, especially with minimal or no heat sink and without liquid cooling, can increase the power-to-volume ratio as well as the power-to-weight ratio for power conversion modules such as a DC-DC converter, inverter etc. A silicon-on-insulator (SOI)-based high-voltage, high-temperature integrated circuit (IC) gate driver for SiC power FETs has been designed and fabricated using a commercially available 0.8-m, 2-poly and 3-metal bipolar-complementary metal oxide semiconductor (CMOS)-double diffused metal oxide semiconductor (DMOS) process. The prototype circuit-s maximum gate drive supply can be 40-V with peak 2.3-A sourcing/sinking current driving capability. Owing to the wide driving range, this gate driver IC can be used to drive a wide variety of SiC FET switches (both normally OFF metal oxide semiconductor field effect transistor (MOSFET) and normally ON junction field effect transistor (JFET)). The switching frequency is 20-kHz and the duty cycle can be varied from 0 to 100-. The circuit has been successfully tested with SiC power MOSFETs and JFETs without any heat sink and cooling mechanism. During these tests, SiC switches were kept at room temperature and ambient temperature of the driver circuit was increased to 200-C. The circuit underwent numerous temperature cycles with negligible performance degradation.

  11. A dual VCDL DLL based gate driver for zero-voltage-switching DC-DC converter

    Science.gov (United States)

    Xin, Tian; Xiangxin, Liu; Wenhong, Li

    2010-07-01

    This paper presents a dual voltage-controlled-delay-line (VCDL) delay-lock-loop (DLL) based gate driver for a zero-voltage-switching (ZVS) DC-DC converter. Using the delay difference of two VCDLs for the dead time control, the dual VCDL DLL is able to implement ZVS control with high accuracy while keeping good linearity performance of the DLL and low power consumption. The design is implemented in the CSM 2P4M 0.35 μm CMOS process. The measurement results indicate that an efficiency improvement of 2%-4% is achieved over the load current range from 100 to 600 mA at 4 MHz switching frequency with 3.3 V input and 1.3 V output voltage.

  12. A dual VCDL DLL based gate driver for zero-voltage-switching DC-DC converter

    Energy Technology Data Exchange (ETDEWEB)

    Tian Xin; Liu Xiangxin; Li Wenhong, E-mail: wenhongli@fudan.edu.c [State Key Laboratory of ASIC and System, Fudan University, Shanghai 201203 (China)

    2010-07-15

    This paper presents a dual voltage-controlled-delay-line (VCDL) delay-lock-loop (DLL) based gate driver for a zero-voltage-switching (ZVS) DC-DC converter. Using the delay difference of two VCDLs for the dead time control, the dual VCDL DLL is able to implement ZVS control with high accuracy while keeping good linearity performance of the DLL and low power consumption. The design is implemented in the CSM 2P4M 0.35 {mu}m CMOS process. The measurement results indicate that an efficiency improvement of 2%-4% is achieved over the load current range from 100 to 600 mA at 4 MHz switching frequency with 3.3 V input and 1.3 V output voltage.

  13. Gate Driver Circuit of Power Electronic Switches with Reduced Number of Isolated DC/DC Converter for a Switched Reluctance Motor

    OpenAIRE

    Ali Asghar Memon; Imtiaz Hussain; Muhammad Aslam Uqaili

    2013-01-01

    This paper presents a gate driver circuit for the switching devices used in the asymmetrical converter for a switched reluctance machine with reduced number of isolated dc/dc converters. Isolation required in the gate driver circuit of switching devices is indispensable. For the purpose of isolation different arrangements may be used such as pulse transformers. The dc/dc converter for isolation and powering the gate drive circuits is suitable, cheaper in cost and simple to implement. It is al...

  14. A wide bandgap silicon carbide (SiC) gate driver for high-temperature and high-voltage applications

    Energy Technology Data Exchange (ETDEWEB)

    Lamichhane, Ranjan [University of Arkansas; Ericson, Milton Nance [ORNL; Frank, Steven Shane [ORNL; BRITTONJr., CHARLES L. [Oak Ridge National Laboratory (ORNL); Marlino, Laura D [ORNL; Mantooth, Alan [University of Arkansas; Francis, Matt [APEI, Inc.; Shepherd, Dr. Paul [University of Arkansas; Glover, Dr. Michael [University of Arkansas; Podar, Mircea [ORNL; Perez, M [University of Arkansas; Mcnutt, Tyler [APEI, Inc.; Whitaker, Mr. Bret [APEI, Inc.; Cole, Mr. Zach [APEI, Inc.

    2014-01-01

    Limitations of silicon (Si) based power electronic devices can be overcome with Silicon Carbide (SiC) because of its remarkable material properties. SiC is a wide bandgap semiconductor material with larger bandgap, lower leakage currents, higher breakdown electric field, and higher thermal conductivity, which promotes higher switching frequencies for high power applications, higher temperature operation, and results in higher power density devices relative to Si [1]. The proposed work is focused on design of a SiC gate driver to drive a SiC power MOSFET, on a Cree SiC process, with rise/fall times (less than 100 ns) suitable for 500 kHz to 1 MHz switching frequency applications. A process optimized gate driver topology design which is significantly different from generic Si circuit design is proposed. The ultimate goal of the project is to integrate this gate driver into a Toyota Prius plug-in hybrid electric vehicle (PHEV) charger module. The application of this high frequency charger will result in lighter, smaller, cheaper, and a more efficient power electronics system.

  15. Gate Driver Circuit of Power Electronic Switches with Reduced Number of Isolated DC/DC Converter for a Switched Reluctance Motor

    Directory of Open Access Journals (Sweden)

    Ali Asghar Memon

    2013-04-01

    Full Text Available This paper presents a gate driver circuit for the switching devices used in the asymmetrical converter for a switched reluctance machine with reduced number of isolated dc/dc converters. Isolation required in the gate driver circuit of switching devices is indispensable. For the purpose of isolation different arrangements may be used such as pulse transformers. The dc/dc converter for isolation and powering the gate drive circuits is suitable, cheaper in cost and simple to implement. It is also significant that required number of isolation converters is much less than the switches used in converter. In addition, a simple logic circuit has been presented for producing the gate signals at correct phase sequence which is compared with the gated signals directly obtained from the encoder of an existing machine.

  16. High-Temperature SiC Power Module with Integrated SiC Gate Drivers for Future High-Density Power Electronics Applications

    Energy Technology Data Exchange (ETDEWEB)

    Whitaker, Mr. Bret [APEI, Inc.; Cole, Mr. Zach [APEI, Inc.; Passmore, Mr. Brandon [APEI, Inc.; Mcnutt, Tyler [APEI, Inc.; Lostetter, Dr. Alex [APEI, Inc.; Ericson, Milton Nance [ORNL; Frank, Steven [ORNL; Britton Jr, Charles L [ORNL; Marlino, Laura D [ORNL; Mantooth, Alan [University of Arkansas; Francis, Matt [APEI, Inc.; Lamichhane, Ranjan [APEI, Inc.; Shepherd, Paul [APEI, Inc.; Glover, Michael [APEI, Inc.

    2014-01-01

    This paper presents a high-temperature capable intelligent power module that contains SiC power devices and SiC gate driver integrated circuits (ICs). The high-temperature capability of the SiC gate driver ICs allows for them to be packaged into the power module and be located physically close to the power devices. This provides a distinct advantage by reducing the gate driver loop inductance, which promotes high frequency operation, while also reducing the overall volume of the system through higher levels of integration. The power module was tested in a bridgeless-boost converter (Fig. 1) to determine the performance of the module in a system level application. The converter was operated with a switching frequency of 200 kHz with a peak output power of approximately 5 kW. The peak efficiency was found to be 97.5% at 2.9 kW.

  17. Silicon-on-insulator-based high-voltage, high-temperature integrated circuit gate driver for silicon carbide-based power field effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Tolbert, Leon M [ORNL; Huque, Mohammad A [ORNL; Blalock, Benjamin J [ORNL; Islam, Syed K [ORNL

    2010-01-01

    Silicon carbide (SiC)-based field effect transistors (FETs) are gaining popularity as switching elements in power electronic circuits designed for high-temperature environments like hybrid electric vehicle, aircraft, well logging, geothermal power generation etc. Like any other power switches, SiC-based power devices also need gate driver circuits to interface them with the logic units. The placement of the gate driver circuit next to the power switch is optimal for minimising system complexity. Successful operation of the gate driver circuit in a harsh environment, especially with minimal or no heat sink and without liquid cooling, can increase the power-to-volume ratio as well as the power-to-weight ratio for power conversion modules such as a DC-DC converter, inverter etc. A silicon-on-insulator (SOI)-based high-voltage, high-temperature integrated circuit (IC) gate driver for SiC power FETs has been designed and fabricated using a commercially available 0.8--m, 2-poly and 3-metal bipolar-complementary metal oxide semiconductor (CMOS)-double diffused metal oxide semiconductor (DMOS) process. The prototype circuit-s maximum gate drive supply can be 40-V with peak 2.3-A sourcing/sinking current driving capability. Owing to the wide driving range, this gate driver IC can be used to drive a wide variety of SiC FET switches (both normally OFF metal oxide semiconductor field effect transistor (MOSFET) and normally ON junction field effect transistor (JFET)). The switching frequency is 20-kHz and the duty cycle can be varied from 0 to 100-. The circuit has been successfully tested with SiC power MOSFETs and JFETs without any heat sink and cooling mechanism. During these tests, SiC switches were kept at room temperature and ambient temperature of the driver circuit was increased to 200-C. The circuit underwent numerous temperature cycles with negligible performance degradation.

  18. Analysis of Active Clamping Circuit in Trench Gate/Field-stop IGBT Driver with Carrier Extraction Model%基于载流子抽取模型的Trench Gate/Field-stop IGBT驱动器有源箝位功能分析

    Institute of Scientific and Technical Information of China (English)

    陈玉香; 罗皓泽; 李武华; 何湘宁

    2016-01-01

    针对Trench gate/Field-stop IGBT结构特有的关断过程中集电极电流下降率不可控问题,引入了载流子抽取模型来模拟器件关断过程中的集电极电流下降阶段器件内部载流子的动态行为特性,并以此为基础分析了驱动器为适应Trench gate/Field-Stop IGBT结构这种关断特性而引入的有源箝位功能的作用机理,验证了载流子抽取模型在器件级与电路级交互作用分析中的实用性,为后续实现器件与电路的最佳匹配奠定了基础.

  19. The Impact of Gate-Driver Parameters Variation and Device Degradation in the PV-Inverter Lifetime

    DEFF Research Database (Denmark)

    Sintamarean, Nicolae Cristian; Wang, Huai; Blaabjerg, Frede;

    2014-01-01

    This paper introduces a reliability-oriented design tool for a new generation of grid connected PV-inverters. The proposed design tool consists of a real field Mission Profile (MP) model (for one year operation in USA-Arizona), a PV-panel model, a grid connected PV-inverter model, an Electro......-Thermal model and the lifetime model of the power semiconductor devices. A simulation model able to consider a one year real field operation conditions (solar irradiance and ambient temperature) is developed. Thus, one year estimation of the converter devices thermal loading distribution is achieved...... and is further used as an input to a lifetime model. The proposed reliability oriented design tool is used to study the impact of MP-variation, Gate-Driver (GD) parameters variation and device degradation in the PVinverter lifetime. The obtained results indicate that in order to improve the accuracy...

  20. The Impact of Gate-Driver Parameters Variation and Device Degradation in the PV-Inverter Lifetime

    DEFF Research Database (Denmark)

    Sintamarean, Nicolae Cristian; Wang, Huai; Blaabjerg, Frede

    2014-01-01

    This paper introduces a reliability-oriented design tool for a new generation of grid connected PV-inverters. The proposed design tool consists of a real field Mission Profile (MP) model (for one year operation in USA-Arizona), a PV-panel model, a grid connected PV-inverter model, an Electro......-Thermal model and the lifetime model of the power semiconductor devices. A simulation model able to consider a one year real field operation conditions (solar irradiance and ambient temperature) is developed. Thus, one year estimation of the converter devices thermal loading distribution is achieved...... and is further used as an input to a lifetime model. The proposed reliability oriented design tool is used to study the impact of MP-variation, Gate-Driver (GD) parameters variation and device degradation in the PVinverter lifetime. The obtained results indicate that in order to improve the accuracy...

  1. Active gate driving method for reliability improvement of IGBTs via junction temperature swing reduction

    DEFF Research Database (Denmark)

    Luo, Haoze; Iannuzzo, Francesco; Ma, Ke

    2016-01-01

    This paper introduces an advanced gate driver used as thermal swing control method for the reduction of AC load current-related ΔTj in Insulated-Gate Bipolar Transistors (IGBTs). A switchable gate resistor network is applied to the advanced gate driver, so that the switching power losses can...... be changed according to the amplitude of AC current. Accordingly, a closed-loop thermal control method including the functions of root-mean-square calculation and phase analysis is proposed. Hence ΔTj can be reduced by means of changing losses-related gate resistors on the basis of output fundamental...... frequency and amplitude of AC load current. As a result, longer device useful life duration can be achieved. Furthermore, the maximum junction temperature under high-temperature operation can be reduced by means of the proposed method. Simulations and experiments are provided to validate the effectiveness...

  2. Switching terahertz waves with gate-controlled active graphene metamaterials.

    Science.gov (United States)

    Lee, Seung Hoon; Choi, Muhan; Kim, Teun-Teun; Lee, Seungwoo; Liu, Ming; Yin, Xiaobo; Choi, Hong Kyw; Lee, Seung S; Choi, Choon-Gi; Choi, Sung-Yool; Zhang, Xiang; Min, Bumki

    2012-11-01

    The extraordinary electronic properties of graphene provided the main thrusts for the rapid advance of graphene electronics. In photonics, the gate-controllable electronic properties of graphene provide a route to efficiently manipulate the interaction of photons with graphene, which has recently sparked keen interest in graphene plasmonics. However, the electro-optic tuning capability of unpatterned graphene alone is still not strong enough for practical optoelectronic applications owing to its non-resonant Drude-like behaviour. Here, we demonstrate that substantial gate-induced persistent switching and linear modulation of terahertz waves can be achieved in a two-dimensional metamaterial, into which an atomically thin, gated two-dimensional graphene layer is integrated. The gate-controllable light-matter interaction in the graphene layer can be greatly enhanced by the strong resonances of the metamaterial. Although the thickness of the embedded single-layer graphene is more than six orders of magnitude smaller than the wavelength (metamaterial, can modulate both the amplitude of the transmitted wave by up to 47% and its phase by 32.2° at room temperature. More interestingly, the gate-controlled active graphene metamaterials show hysteretic behaviour in the transmission of terahertz waves, which is indicative of persistent photonic memory effects.

  3. High-Temperature SiC Power Module with Integrated SiC Gate Drivers for Future High-Density Power Electronics Applications

    Energy Technology Data Exchange (ETDEWEB)

    Whitaker, Mr. Bret [APEI, Inc.; Cole, Mr. Zach [APEI, Inc.; Passmore, Mr. Brandon [APEI, Inc.; Martin, Daniel [APEI, Inc.; Mcnutt, Tyler [APEI, Inc.; Lostetter, Dr. Alex [APEI, Inc.; Ericson, Milton Nance [ORNL; Frank, Steven Shane [ORNL; Britton Jr, Charles L [ORNL; Marlino, Laura D [ORNL; Mantooth, Alan [University of Arkansas; Francis, Dr. Matt [University of Arkansas; Lamichhane, Ranjan [University of Arkansas; Shepherd, Dr. Paul [University of Arkansas; Glover, Dr. Michael [University of Arkansas

    2014-01-01

    This paper presents the testing results of an all-silicon carbide (SiC) intelligent power module (IPM) for use in future high-density power electronics applications. The IPM has high-temperature capability and contains both SiC power devices and SiC gate driver integrated circuits (ICs). The high-temperature capability of the SiC gate driver ICs allows for them to be packaged into the power module and be located physically close to the power devices. This provides a distinct advantage by reducing the gate driver loop inductance, which promotes high frequency operation, while also reducing the overall volume of the system through higher levels of integration. The power module was tested in a bridgeless-boost converter to showcase the performance of the module in a system level application. The converter was initially operated with a switching frequency of 200 kHz with a peak output power of approximately 5 kW. The efficiency of the converter was then evaluated experimentally and optimized by increasing the overdrive voltage on the SiC gate driver ICs. Overall a peak efficiency of 97.7% was measured at 3.0 kW output. The converter s switching frequency was then increased to 500 kHz to prove the high frequency capability of the power module was then pushed to its limits and operated at a switching frequency of 500 kHz. With no further optimization of components, the converter was able to operate under these conditions and showed a peak efficiency of 95.0% at an output power of 2.1 kW.

  4. Active Drivers of Adoption of Internet Banking

    Directory of Open Access Journals (Sweden)

    Pankaj Yadav

    2016-05-01

    Full Text Available Application of internet by banking sector in India has changed the definition of banking completely. The management of different banks has been making concrete efforts to facilitate the acceptance of i-banking by bringing out its benefits to the customers. This paper identifies the active factors that influence customers intention regarding use of internet banking in Himachal Pradesh  Data was collected from a sample of 120 respondents through a well structured questionnaire. The data was collected from Government employees of Shimla district of Himachal Pradesh by asking close ended questions regarding their attitude towards i-banking and their future intention about its use . For analysing and interpreting data in the present study, basic statistical tools, chi-square test (test of independence and logistical regression analysis was used with the help of SPSS 16.0 version. Out of seven factors i.e., perceived risk, perceived usefulness,  perceived quality of service, Perceived cost, Perceived ease of use, trust and awareness, three significant factors i.e., perceived risk, perceived usefulness  and perceived quality of service have been identified that actively influence future adoption intention to adopt internet banking . Further the study exhibited that perceived usefulness and perceived quality of service positively influence the intention to adopt i-banking while perceived risk negatively affect the future adoption intention of i-banking. This  model has the overall predictability of classifying 76.7 % cases correctly and exhibited that 87.2 % customers are classified for adopting i-banking service whereas 57.1 % customers for not having intention to use it in future

  5. Perchlorate Reductase Is Distinguished by Active Site Aromatic Gate Residues.

    Science.gov (United States)

    Youngblut, Matthew D; Tsai, Chi-Lin; Clark, Iain C; Carlson, Hans K; Maglaqui, Adrian P; Gau-Pan, Phonchien S; Redford, Steven A; Wong, Alan; Tainer, John A; Coates, John D

    2016-04-22

    Perchlorate is an important ion on both Earth and Mars. Perchlorate reductase (PcrAB), a specialized member of the dimethylsulfoxide reductase superfamily, catalyzes the first step of microbial perchlorate respiration, but little is known about the biochemistry, specificity, structure, and mechanism of PcrAB. Here we characterize the biophysics and phylogeny of this enzyme and report the 1.86-Å resolution PcrAB complex crystal structure. Biochemical analysis revealed a relatively high perchlorate affinity (Km = 6 μm) and a characteristic substrate inhibition compared with the highly similar respiratory nitrate reductase NarGHI, which has a relatively much lower affinity for perchlorate (Km = 1.1 mm) and no substrate inhibition. Structural analysis of oxidized and reduced PcrAB with and without the substrate analog SeO3 (2-) bound to the active site identified key residues in the positively charged and funnel-shaped substrate access tunnel that gated substrate entrance and product release while trapping transiently produced chlorate. The structures suggest gating was associated with shifts of a Phe residue between open and closed conformations plus an Asp residue carboxylate shift between monodentate and bidentate coordination to the active site molybdenum atom. Taken together, structural and mutational analyses of gate residues suggest key roles of these gate residues for substrate entrance and product release. Our combined results provide the first detailed structural insight into the mechanism of biological perchlorate reduction, a critical component of the chlorine redox cycle on Earth.

  6. Research data management and libraries: relationships, activities, drivers and influences.

    Science.gov (United States)

    Pinfield, Stephen; Cox, Andrew M; Smith, Jen

    2014-01-01

    The management of research data is now a major challenge for research organisations. Vast quantities of born-digital data are being produced in a wide variety of forms at a rapid rate in universities. This paper analyses the contribution of academic libraries to research data management (RDM) in the wider institutional context. In particular it: examines the roles and relationships involved in RDM, identifies the main components of an RDM programme, evaluates the major drivers for RDM activities, and analyses the key factors influencing the shape of RDM developments. The study is written from the perspective of library professionals, analysing data from 26 semi-structured interviews of library staff from different UK institutions. This is an early qualitative contribution to the topic complementing existing quantitative and case study approaches. Results show that although libraries are playing a significant role in RDM, there is uncertainty and variation in the relationship with other stakeholders such as IT services and research support offices. Current emphases in RDM programmes are on developments of policies and guidelines, with some early work on technology infrastructures and support services. Drivers for developments include storage, security, quality, compliance, preservation, and sharing with libraries associated most closely with the last three. The paper also highlights a 'jurisdictional' driver in which libraries are claiming a role in this space. A wide range of factors, including governance, resourcing and skills, are identified as influencing ongoing developments. From the analysis, a model is constructed designed to capture the main aspects of an institutional RDM programme. This model helps to clarify the different issues involved in RDM, identifying layers of activity, multiple stakeholders and drivers, and a large number of factors influencing the implementation of any initiative. Institutions may usefully benchmark their activities against the

  7. A rugged 650 V SOI-based high-voltage half-bridge IGBT gate driver IC for motor drive applications

    Science.gov (United States)

    Hua, Qing; Li, Zehong; Zhang, Bo; Chen, Weizhong; Huang, Xiangjun; Feng, Yuxiang

    2015-05-01

    This paper proposes a rugged high-voltage N-channel insulated gate bipolar transistor (IGBT) gate driver integrated circuit. The device integrates a high-side and a low-side output stages on a single chip, which is designed specifically for motor drive applications. High-voltage level shift technology enables the high-side stage of this device to operate up to 650 V. The logic inputs are complementary metal oxide semiconductor (CMOS)/transistor transistor logic compatible down to 3.3 V. Undervoltage protection functionality with hysteresis characteristic has also been integrated to enhance the device reliability. The device is fabricated in a 1.0 μm, 650 V high-voltage bipolar CMOS double-diffused metal oxide semiconductor (BCD) on silicon-on-insulator (SOI) process. Deep trench dielectric isolation technology is employed to provide complete electrical isolation with advantages such as reduced parasitic effects, excellent noise immunity and low leakage current. Experimental results show that the isolation voltage of this device can be up to approximately 779 V at 25°C, and the leakage current is only 5 nA at 650 V, which is 15% higher and 67% lower than the conventional ones. In addition, it delivers an excellent thermal stability and needs very low quiescent current and offers a high gate driver capability which is needed to adequately drive IGBTs that have large input capacitances.

  8. Electronics drivers for high voltage dielectric electro active polymer (DEAP) applications

    DEFF Research Database (Denmark)

    Zhang, Zhe; Andersen, Michael A. E.

    2015-01-01

    ), but the voltage balancing across the series - connected high voltage IGBTs is a critical issue and accordi ngly a novel gate driver circuitry is proposed and equipped; due to the requirements of the audio products, such as low distortion and noise, the multi - level Buck converter based Class - D amplifier...

  9. Switching Performance Evaluation of Commercial SiC Power Devices (SiC JFET and SiC MOSFET) in Relation to the Gate Driver Complexity

    DEFF Research Database (Denmark)

    Pittini, Riccardo; Zhang, Zhe; Andersen, Michael A. E.

    2013-01-01

    and JFETs. The recent introduction of SiC MOSFET has proved that it is possible to have highly performing SiC devices with a minimum gate driver complexity; this made SiC power devices even more attractive despite their device cost. This paper presents an analysis based on experimental results...... of the switching losses of various commercially available Si and SiC power devices rated at 1200 V (Si IGBTs, SiC JFETs and SiC MOSFETs). The comparison evaluates the reduction of the switching losses which is achievable with the introduction of SiC power devices; this includes analysis and considerations...

  10. Fast Robust Gate-Drivers with Easy Adjustable Voltage Ranges for Driving Normally-On Wide-Bandgap Power Transistors

    OpenAIRE

    Jacqmaer, Pieter; Everts, Jordi; Gelagaev, Ratmir; Tant, Peter; Driesen, Johan

    2010-01-01

    Wide-bandgap (WBG) semiconductors, such as gallium nitride (GaN), are more and more being used in switching power devices. An AlGaN/GaN/AlGaN Double Heterojunction Field Effect transistor (DHFET) was developed in previous work and needed to be tested. The used test circuit was a buck converter. This type of converter, in addition with the normally-on switching behaviour of the GaN-based transistors, requires dedicated gate drive circuitry, resulting in the development of three types of gate-d...

  11. ALTERNATIVE EQUATIONS FOR DYNAMIC BEHAVIOR OF IONIC CHANNEL ACTIVATION AND INACTIVATION GATES

    Directory of Open Access Journals (Sweden)

    Mahmut ÖZER

    2003-03-01

    Full Text Available In this paper, alternative equations for dynamics of ionic channel activation and inactivation gates are proposed based on the path probability method. Dynamic behavior of a voltage-gated ionic channel is modeled by the conventional Hodgkin-Huxley (H-H mathematical formalism. In that model, conductance of the channel is defined in terms of activation and inactivation gates. Dynamics of the activation and inactivation gates is modeled by first-order differential equations dependent on the gate variable and the membrane potential. In the new approach proposed in this study, dynamic behavior of activation and inactivation gates is modeled by a firstorder differential equation dependent on internal energy and membrane potential by using the path probability method which is widely used in statistical physics. The new model doesn't require the time constant and steadystate values which are used explicitly in the H-H model. The numerical results show validity of the proposed method.

  12. Electronics drivers for high voltage dielectric electro active polymer (DEAP) applications

    Science.gov (United States)

    Zhang, Zhe; Andersen, Michael A. E.

    2015-04-01

    Dielectric electro active polymer (DEAP) can be used in actuation, sensing and energy harvesting applications, but driving the DEAP based actuators and generators has three main challenges from a power electronics standpoint, i.e. high voltage (around 2.5 kV), nonlinearity, and capacitive behavior. In this paper, electronics divers for heating valves, loud speakers, incremental motors, and energy harvesting are reviewed, studied and developed in accordance with their corresponding specifications. Due to the simplicity and low power capacity (below 10W), the reversible Fly-back converters with both magnetic and piezoelectric transformers are employed for the heating valve and incremental motor application, where only ON/OFF regulation is adopted for energy saving; as for DEAP based energy harvesting, the noisolated Buck/Boost converter is used, due to the system high power capacity (above 100W), but the voltage balancing across the series-connected high voltage IGBTs is a critical issue and accordingly a novel gate driver circuitry is proposed and equipped; due to the requirements of the audio products, such as low distortion and noise, the multi-level Buck converter based Class-D amplifier, because of its high control linearity, is implemented for the loud speaker applications. A synthesis among those converter topologies and control techniques is given; therefore, for those DEAP based applications, their diversity and similarity of electronics drivers, as well as the key technologies employed are analyzed. Therefore a whole picture of how to choose the proper topologies can be revealed. Finally, the design guidelines in order to achieve high efficiency and reliability are discussed.

  13. Antibody activation using DNA-based logic gates.

    Science.gov (United States)

    Janssen, Brian M G; van Rosmalen, Martijn; van Beek, Lotte; Merkx, Maarten

    2015-02-16

    Oligonucleotide-based molecular circuits offer the exciting possibility to introduce autonomous signal processing in biomedicine, synthetic biology, and molecular diagnostics. Here we introduce bivalent peptide-DNA conjugates as generic, noncovalent, and easily applicable molecular locks that allow the control of antibody activity using toehold-mediated strand displacement reactions. Employing yeast as a cellular model system, reversible control of antibody targeting is demonstrated with low nM concentrations of peptide-DNA locks and oligonucleotide displacer strands. Introduction of two different toehold strands on the peptide-DNA lock allowed signal integration of two different inputs, yielding logic OR- and AND-gates. The range of molecular inputs could be further extended to protein-based triggers by using protein-binding aptamers. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Performance Evaluation of an Automotive-Grade, High Speed Gate Driver for SiC FETs, Type UCC27531, Over a Wide Temperature Range

    Science.gov (United States)

    Boomer, Kristen; Hammoud, Ahmad

    2015-01-01

    Silicon carbide (SiC) devices are becoming widely used in electronic power circuits as replacement for conventional silicon parts due to their attractive properties that include low on-state resistance, high temperature tolerance, and high frequency operation. These attributes have a significant impact by reducing system weight, saving board space, and conserving power. In this work, the performance of an automotive-grade high speed gate driver with potential use in controlling SiC FETs (field-Effect Transistors) in converters or motor control applications was evaluated under extreme temperatures and thermal cycling. The investigations were carried out to assess performance and to determine suitability of this device for use in space exploration missions under extreme temperature conditions.

  15. 一种零死区栅驱动电路的设计%Design of a Zero Dead-Time Gate-Driver Circuit

    Institute of Scientific and Technical Information of China (English)

    石跃; 朱世鸿; 黄建刚

    2013-01-01

    A novel structure of zero dead time gate driver circuit was designed,which was applicable for a variety of synchronous rectification structures,and its feasibility was verified using Class D amplifier with full-bridge output structure.This circuit avoided conduction of parasitic body diode on power MOSFET by making output synchronous rectifying power MOSFET switching simultaneously,thus canceling the electro-magnetic interference (EMI) caused by conduction of body diode.Simulation based on 0.6 μm BCD process showed that,when the punch-through current was less than 45 mA,the zero dead-time gate-driver circuit could ensure that the parasitic body diode on power MOSFET would not be turned on for a load current below 300 mA.%设计了一种结构新颖、适用于各种同步整流结构的零死区栅驱动电路,并在全桥输出结构的D类放大器中对其可行性进行了验证.通过控制输出同步整流功率管在开关过程中同时切换,避免了功率管寄生体二极管的开启,从而消除了体二极管导通产生的电磁干扰.基于0.6μmBCD工艺,对提出的零死区栅驱动电路进行仿真验证,结果表明,当穿通电流小于45 mA时,可以保证在300 mA以内负载电流下功率管的寄生体二极管不开启.

  16. Effects of Neighborhood’s Built Environment on Physical Activities in Gated Communities: A Review

    Directory of Open Access Journals (Sweden)

    Yasmeen Gul

    2016-01-01

    Full Text Available The emergence of gated communities throughout the world has generated significant academic interest. Several studies have been carried out that can be found in the body of literature, which have attempted to investigate the various aspects of life within the gated communities. The range of subjects studied within this context includes the types of gated communities, the associated social and governance issues, the travel patterns, and the daily physical activities. The focus of most of these studies, however, has been on the social and governance issues while a little research on the mobility pattern (i.e. walking, cycling and public transport and physical activities in gated communities has been reported, the available literature suffers from major shortcomings such as identification of suitable indicators to investigate whether these communities have same effects on mobility patterns and physical activities as non-gated communities. The present paper, therefore, attempts to identify the methods for objective as well as subjective study of the mobility patterns and neighborhoods design which affect the physical activities through a systematic review of available literature. The paper identifies suitable indicators to investigate the rate of physical activity in gated communities. Attempt will be made to clearly chart the differences as well as similarities between the issues concerned with physical activity in gated communities and non-gated communities and attempts to introduce new objectives for future studies. The findings of this study are expected to help design an investigation into the merits or otherwise of the active living neighborhoods.

  17. Switching teraherz waves with gate-controlled active graphene metamaterials

    CERN Document Server

    Lee, Seung Hoon; Kim, Teun-Teun; Lee, Seungwoo; Liu, Ming; Yin, Xiaobo; Choi, Hong Kyw; Lee, Seung S; Choi, Choon-Gi; Choi, Sung-Yool; Zhang, Xiang; Min, Bumki

    2012-01-01

    The extraordinary electronic properties of graphene, such as its continuously gate-variable ambipolar field effect and the resulting steep change in resistivity, provided the main thrusts for the rapid advance of graphene electronics. The gate-controllable electronic properties of graphene provide a route to efficiently manipulate the interaction of low-energy photons with massless Dirac fermions, which has recently sparked keen interest in graphene plasmonics. However, the electro-optic tuning capability of unpatterned graphene alone is still not strong enough for practical optoelectronic applications due to its nonresonant Drude-like behaviour. Here, we experimentally demonstrate that substantial gate-induced persistent switching and linear modulation of terahertz waves can be achieved in a two-dimensional artificial material, referred to as a metamaterial, into which an atomically thin, gated two-dimensional graphene layer is integrated. The gate-controllable light-matter interaction in the graphene layer ...

  18. Biogeochemical drivers of microbial community convergence across actively retreating glaciers

    Energy Technology Data Exchange (ETDEWEB)

    Castle, Sarah C.; Nemergut, Diana R.; Grandy, A. Stuart; Leff, Jonathan W.; Graham, Emily B.; Hood, Eran; Schmidt, Steven K.; Wickings, Kyle; Cleveland, Cory C.

    2016-10-01

    The ecological processes that influence biogeographical patterns of microorganisms are actively debated. To investigate how such patterns emerge during ecosystem succession, we examined the biogeochemical drivers of bacterial community assembly in soils over two environmentally distinct, recently deglaciated chronosequences separated by a distance of more than 1,300 kilometers. Our results show that despite different geographic, climatic, and soil chemical and physical characteristics at the two sites, soil bacterial community structure and decomposer function converged during plant succession. In a comparative analysis, we found that microbial communities in early succession soils were compositionally distinct from a group of diverse, mature forest soils, but that the differences between successional soils and mature soils decreased from early to late stages of succession. Differences in bacterial community composition across glacial sites were largely explained by pH. However, successional patterns and community convergence across sites were more consistently related to soil organic carbon and organic matter chemistry, which appeared to be tightly coupled with bacterial community structure across both young and mature soils.

  19. Mechanism of activation gating in the full-length KcsA K[superscript +] channel

    Energy Technology Data Exchange (ETDEWEB)

    Uysal, Serdar; Cuello, Luis G.; Cortes, D. Marien; Koide, Shohei; Kossiakoff, Anthony A.; Perozo, Eduardo (UC)

    2012-10-25

    Using a constitutively active channel mutant, we solved the structure of full-length KcsA in the open conformation at 3.9 {angstrom}. The structure reveals that the activation gate expands about 20 {angstrom}, exerting a strain on the bulge helices in the C-terminal domain and generating side windows large enough to accommodate hydrated K{sup +} ions. Functional and spectroscopic analysis of the gating transition provides direct insight into the allosteric coupling between the activation gate and the selectivity filter. We show that the movement of the inner gate helix is transmitted to the C-terminus as a straightforward expansion, leading to an upward movement and the insertion of the top third of the bulge helix into the membrane. We suggest that by limiting the extent to which the inner gate can open, the cytoplasmic domain also modulates the level of inactivation occurring at the selectivity filter.

  20. Ligand-Gated Ion Channels: Permeation and Activation1

    Science.gov (United States)

    Lynch, Joseph W.; Barry, Peter H.

    Ligand-gated ion channels (LGICs) are fast-responding channels in which the receptor, which binds the activating molecule (the ligand), and the ion channel are part of the same nanomolecular protein complex. This chapter will describe the properties and functions of the nicotinic acetylcholine LGIC superfamily, which play a critical role in the fast chemical transmission of electrical signals between nerve cells at synapses and between nerve and muscle cells at endplates. All the processing functions of the brain and the resulting behavioral output depend on chemical transmission across such neuronal interconnections. To describe the properties of the channels of this LGIC superfamily,we will mainly use two examples of this family of channels: the excitatory nicotinic acetylcholine receptor (nAChR) and the inhibitory glycine receptor (GlyR) channels. In the chemical transmission of electrical signals, the arrival of an electrical signal at the synaptic terminal of a nerve causes the release of a chemical signal—a neurotransmitter molecule (the ligand, also referred to as the agonist). The neurotransmitter rapidly diffuses across the very narrow 20-40 nm synaptic gap between the cells and binds to the LGIC receptors in the membrane of the target (postsynaptic) cell and generates a new electrical signal in that cell (e.g., Kandel et al., 2000). How this chemical signal is converted into an electrical one depends on the fundamental properties of LGICs and the ionic composition of the postsynaptic cell and its external solution.

  1. Active Versus Passive Acquisition of Spatial Knowledge While Controlling a Vehicle in a Virtual Urban Space in Drivers and Non-Drivers

    Directory of Open Access Journals (Sweden)

    George Sandamas

    2015-07-01

    Full Text Available Historically, real-world studies have indicated a spatial learning advantage for people who actively explore the environment they inhabit as opposed to those whose experience is more passive. A common contrast is made between the spatial learning of car drivers and passengers. However, compared with walking and other forms of transportation, car-driving experience per se has a special status. An experiment was conducted to explore the dual hypotheses that active explorers learn more about the layout of a virtual environment (VE than passive observers and that real-world car drivers will learn more regardless of their experimental active/passive status. Participants explored a virtual model of a small town in active/passive, pairs. Active exploration was self-directed and goal driven, and all learning tasks were explicit. Consistent with many earlier studies in VEs, there was no benefit from activity (controlling exploration/movement, arguably because input control competes with spatial information acquisition. When participants were divided according to whether they were licensed drivers or not, the results showed that drivers were significantly more accurate than non-drivers at indicating the positions of target locations on a map, in both the active and passive conditions. An interaction showed that in the active condition, drivers had significantly better route scores than non-drivers, and better than drivers in the passive condition. Driving may therefore be beneficial for spatial abilities over and above the general benefits of “activity” and when spatial skills are examined in VEs, driver experience is an important criterion that should be taken into account.

  2. 4.0-inch Active-Matrix Organic Light-Emitting Diode Display Integrated with Driver Circuits Using Amorphous In-Ga-Zn-Oxide Thin-Film Transistors with Suppressed Variation

    Science.gov (United States)

    Ohara, Hiroki; Sasaki, Toshinari; Noda, Kousei; Ito, Shunichi; Sasaki, Miyuki; Endo, Yuta; Yoshitomi, Shuhei; Sakata, Junichiro; Serikawa, Tadashi; Yamazaki, Shunpei

    2010-03-01

    We have newly developed a 4.0-in. quarter video graphics array (QVGA) active-matrix organic light-emitting diode (AMOLED) display integrated with gate and source driver circuits using amorphous In-Ga-Zn-oxide (IGZO) thin-film transistors (TFTs). Focusing on a passivation layer in an inverted staggered bottom gate structure, the threshold voltage of the TFTs can be controlled to have “normally-off” characteristics with suppressed variation by using a SiOx layer formed by sputtering with a low hydrogen content. In addition, small subthreshold swing S/S of 0.19 V/decade, high field-effect mobility µFE of 11.5 cm2 V-1 s-1, and threshold voltage Vth of 1.27 V are achieved. The deposition conditions of the passivation layer and other processes are optimized, and variation in TFT characteristics is suppressed, whereby high-speed operation in gate and source driver circuits can be achieved. Using these driver circuits, the 4.0-in. QVGA AMOLED display integrated with driver circuits can be realized.

  3. A leucine zipper motif essential for gating of hyperpolarization-activated channels.

    Science.gov (United States)

    Wemhöner, Konstantin; Silbernagel, Nicole; Marzian, Stefanie; Netter, Michael F; Rinné, Susanne; Stansfeld, Phillip J; Decher, Niels

    2012-11-23

    It is poorly understood how hyperpolarization-activated cyclic nucleotide-gated channels (HCNs) function. We have identified a leucine zipper in the S5 segment of HCNs, regulating hyperpolarization-activated and instantaneous current components. The leucine zipper is essential for HCN channel gating. The identification and functional characterization of the leucine zipper is an important step toward the understanding of HCN channel function. Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are pacemakers in cardiac myocytes and neurons. Although their membrane topology closely resembles that of voltage-gated K(+) channels, the mechanism of their unique gating behavior in response to hyperpolarization is still poorly understood. We have identified a highly conserved leucine zipper motif in the S5 segment of HCN family members. In order to study the role of this motif for channel function, the leucine residues of the zipper were individually mutated to alanine, arginine, or glutamine residues. Leucine zipper mutants traffic to the plasma membrane, but the channels lose their sensitivity to open upon hyperpolarization. Thus, our data indicate that the leucine zipper is an important molecular determinant for hyperpolarization-activated channel gating. Residues of the leucine zipper interact with the adjacent S6 segment of the channel. This interaction is essential for voltage-dependent gating of the channel. The lower part of the leucine zipper, at the intracellular mouth of the channel, is important for stabilizing the closed state. Mutations at these sites increase current amplitudes or result in channels with deficient closing and increased min-P(o). Our data are further supported by homology models of the open and closed state of the HCN2 channel pore. Thus, we conclude that the leucine zipper of HCN channels is a major determinant for hyperpolarization-activated channel gating.

  4. Light-induced regulation of ligand-gated channel activity.

    Science.gov (United States)

    Bregestovski, Piotr; Maleeva, Galyna; Gorostiza, Pau

    2017-08-31

    The control of ligand-gated receptors with light using photochromic compounds has evolved from the first handcrafted examples to accurate, engineered receptors, whose development is supported by rational design, high-resolution protein structures, comparative pharmacology and molecular biology manipulations. Photoswitchable regulators have been designed and characterized for a large number of ligand-gated receptors in the mammalian nervous system, including nicotinic acetylcholine, glutamate and GABA receptors. They provide a well-equipped toolbox to investigate synaptic and neuronal circuits in all-optical experiments. This focused review discusses the design and properties of these photoswitches, their applications and shortcomings and future perspectives in the field. © 2017 The British Pharmacological Society.

  5. A Leucine Zipper Motif Essential for Gating of Hyperpolarization-activated Channels*

    Science.gov (United States)

    Wemhöner, Konstantin; Silbernagel, Nicole; Marzian, Stefanie; Netter, Michael F.; Rinné, Susanne; Stansfeld, Phillip J.; Decher, Niels

    2012-01-01

    Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are pacemakers in cardiac myocytes and neurons. Although their membrane topology closely resembles that of voltage-gated K+ channels, the mechanism of their unique gating behavior in response to hyperpolarization is still poorly understood. We have identified a highly conserved leucine zipper motif in the S5 segment of HCN family members. In order to study the role of this motif for channel function, the leucine residues of the zipper were individually mutated to alanine, arginine, or glutamine residues. Leucine zipper mutants traffic to the plasma membrane, but the channels lose their sensitivity to open upon hyperpolarization. Thus, our data indicate that the leucine zipper is an important molecular determinant for hyperpolarization-activated channel gating. Residues of the leucine zipper interact with the adjacent S6 segment of the channel. This interaction is essential for voltage-dependent gating of the channel. The lower part of the leucine zipper, at the intracellular mouth of the channel, is important for stabilizing the closed state. Mutations at these sites increase current amplitudes or result in channels with deficient closing and increased min-Po. Our data are further supported by homology models of the open and closed state of the HCN2 channel pore. Thus, we conclude that the leucine zipper of HCN channels is a major determinant for hyperpolarization-activated channel gating. PMID:23048023

  6. Being flexible: the voltage-controllable activation gate of Kv channels

    Directory of Open Access Journals (Sweden)

    Alain J. Labro

    2012-09-01

    Full Text Available Kv channels form voltage-dependent potassium selective pores in the outer cell membrane and are composed out of four -subunits, each having six membrane-spanning -helices (S1-S6. The -subunits tetramerize such that the S5-S6 pore domains co-assemble into a centrally located K+ pore which is surrounded by four operational voltage sensing domains (VSD that are each formed by the S1-S4 segments. Consequently, each subunit is capable of responding to changes in membrane potential and dictates whether the pore should be conductive or not. K+ permeation through the pore can be sealed off by two separate gates in series: (a at the inner S6 bundle crossing (BC gate and (b at the level of the selectivity-filter (SF gate located at the extracellular entrance of the pore. Within the last years a general consensus emerged that a direct communication between the S4S5-linker and the bottom part of S6 (S6c constitutes the coupling with the VSD thus making the BC gate the main voltage-controllable activation gate. While the BC gate listens to the VSD, the SF changes its conformation depending on the status of the BC gate. Through the eyes of an entering K+ ion, the operation of the BC gate apparatus can be compared with the iris-like motion of the diaphragm from a camera whereby its diameter widens. Two main gating motions have been proposed to create this BC gate widening: (1 tilting of the helix whereby the S6 converts from a straight -helix to a tilted one or (2 swiveling of the S6c whereby the S6 remains bent. Such motions require a flexible hinge that decouples the pre- and post-hinge segment. Roughly at the middle of the S6 there exists a highly conserved glycine residue and a tandem proline motif that seem to fulfill the role of a gating hinge which allows for tilting/swiveling/rotations of the post-hinge S6 segment. In this review we delineate our current view on the operation of the BC gate for controlling K+ permeation in Kv channels.

  7. Effects of irregular-shift work and physical activity on cardiovascular risk factors in truck drivers.

    Science.gov (United States)

    Marqueze, Elaine Cristina; Ulhôa, Melissa Araújo; Moreno, Claudia Roberta de Castro

    2013-06-01

    To analyze the putative effect of type of shift and its interaction with leisure-time physical activity on cardiovascular risk factors in truck drivers. A cross-sectional study was undertaken on 57 male truck drivers working at a transportation company, of whom 31 worked irregular shifts and 26 worked on the day-shift. Participants recorded their physical activity using the International Physical Activity Questionnaire along with measurements of blood pressure, body mass index and waist-hip ratio. Participants also provided a fasting blood sample for analysis of lipid-related outcomes. Data were analyzed using a factorial model which was covariate-controlled for age, smoking, work demand, control at work and social support. Most of the irregular-shift and day-shift workers worked more than 8 hours per day (67.7% and 73.1%, respectively). The mean duration of experience working the irregular schedule was 15.7 years. Day-shift workers had never engaged in irregular-shift work and had been working as a truck driver for 10.8 years on average. The irregular-shift drivers had lower work demand but less control compared to day-shift drivers (p active irregular-shift workers had higher systolic and diastolic arterial pressures (143.7 and 93.2 mmHg, respectively) than moderately-active day-shift workers (116 and 73.3 mmHg, respectively) (p physical activity, irregular-shift drivers had higher total cholesterol and LDL-cholesterol concentrations (211.8 and 135.7 mg/dl, respectively) than day-shift workers (161.9 and 96.7 mg/dl, respectively (ANCOVA, p physical activity.

  8. Voltage-dependent gating of hyperpolarization-activated, cyclic nucleotide-gated pacemaker channels: molecular coupling between the S4-S5 and C-linkers.

    Science.gov (United States)

    Decher, Niels; Chen, Jun; Sanguinetti, Michael C

    2004-04-02

    Hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels have a transmembrane topology that is highly similar to voltage-gated K(+) channels, yet HCN channels open in response to membrane hyperpolarization instead of depolarization. The structural basis for the "inverted" voltage dependence of HCN gating and how voltage sensing by the S1-S4 domains is coupled to the opening of the intracellular gate formed by the S6 domain are unknown. Coupling could arise from interaction between specific residues or entire transmembrane domains. We previously reported that the mutation of specific residues in the S4-S5 linker of HCN2 (i.e. Tyr-331 and Arg-339) prevented normal channel closure presumably by disruption of a crucial interaction with the activation gate. Here we hypothesized that the C-linker, a carboxyl terminus segment that connects S6 to the cyclic nucleotide binding domain, interacts with specific residues of the S4-S5 linker to mediate coupling. The recently solved structure of the C-linker of HCN2 indicates that an alpha-helix (the A'-helix) is located near the end of each S6 domain, the presumed location of the activation gate. Ala-scanning mutagenesis of the end of S6 and the A'-helix identified five residues that were important for normal gating as mutations disrupted channel closure. However, partial deletion of the C-linker indicated that the presence of only two of these residues was required for normal coupling. Further mutation analyses suggested that a specific electrostatic interaction between Arg-339 of the S4-S5 linker and Asp-443 of the C-linker stabilizes the closed state and thus participates in the coupling of voltage sensing and activation gating in HCN channels.

  9. STIM1 activates CRAC channels through rotation of the pore helix to open a hydrophobic gate

    Science.gov (United States)

    Yamashita, Megumi; Yeung, Priscilla S.-W.; Ing, Christopher E.; McNally, Beth A.; Pomès, Régis; Prakriya, Murali

    2017-02-01

    Store-operated Ca2+ release-activated Ca2+ (CRAC) channels constitute a major pathway for Ca2+ influx and mediate many essential signalling functions in animal cells, yet how they open remains elusive. Here, we investigate the gating mechanism of the human CRAC channel Orai1 by its activator, stromal interacting molecule 1 (STIM1). We find that two rings of pore-lining residues, V102 and F99, work together to form a hydrophobic gate. Mutations of these residues to polar amino acids produce channels with leaky gates that conduct ions in the resting state. STIM1-mediated channel activation occurs through rotation of the pore helix, which displaces the F99 residues away from the pore axis to increase pore hydration, allowing ions to flow through the V102-F99 hydrophobic band. Pore helix rotation by STIM1 also explains the dynamic coupling between CRAC channel gating and ion selectivity. This hydrophobic gating mechanism has implications for CRAC channel function, pharmacology and disease-causing mutations.

  10. Electronics drivers for high voltage dielectric electro active polymer (DEAP) applications

    DEFF Research Database (Denmark)

    Zhang, Zhe; Andersen, Michael A. E.

    2015-01-01

    magnetic and piezoelectric transformers are employed for the heating valve and incremental motor application, where only ON/OFF regulation is adopted fo r energy saving; as for DEAP based energy harvesting, the no - isolated Buck/Boost converter is used, due to the system high power capacity (above 100W......), but the voltage balancing across the series - connected high voltage IGBTs is a critical issue and accordi ngly a novel gate driver circuitry is proposed and equipped; due to the requirements of the audio products, such as low distortion and noise, the multi - level Buck converter based Class - D amplifier....... In this paper, electronics divers for heating valves, loud speakers, incremental motors, and energy harvesting are reviewed, studied and developed in accordance with their corresponding specifications. Due to the simplicity and low power capacity (below 10W), the reversible Fly - back converters with both...

  11. Physical activity overcomes the effects of cumulative work time on hypertension prevalence among Brazilian taxi drivers.

    Science.gov (United States)

    Vieira, Marcelo C; Sperandei, Sandro; Reis, Arianne C

    2016-05-01

    The aim of this study was to assess the physical activity profile of taxi drivers and its relationship with hypertension prevalence in this group of workers. Cross sectional exploratory study. Between November 2008 and April 2009, 491 taxi drivers from Rio de Janeiro, Brazil, answered a questionnaire focusing on previous hypertension diagnosis, occupational characteristics and physical activity habits. Two logistic models were developed to determine risk factors related to hypertension and to find variables associated with a higher probability of sedentarism. Hypertension prevalence was 22.6%. The workload of the group investigated was high. Results indicate that 'age', 'Body Mass Index', 'physical activity', and 'years as a taxi driver' are related to the probability of hypertension. Physical activity was shown to be a protection factor for hypertension, even considering the deleterious effect of time as a taxi driver. Our results also determined that the practice of physical activity is influenced by age, level of education and workload. It is recommended that programs to combat sedentary lifestyles as well as measures to reduce workloads be developed as strategies to prevent hypertension.

  12. Active training and driving-specific feedback improve older drivers' visual search prior to lane changes

    Directory of Open Access Journals (Sweden)

    Lavallière Martin

    2012-03-01

    Full Text Available Abstract Background Driving retraining classes may offer an opportunity to attenuate some effects of aging that may alter driving skills. Unfortunately, there is evidence that classroom programs (driving refresher courses do not improve the driving performance of older drivers. The aim of the current study was to evaluate if simulator training sessions with video-based feedback can modify visual search behaviors of older drivers while changing lanes in urban driving. Methods In order to evaluate the effectiveness of the video-based feedback training, 10 older drivers who received a driving refresher course and feedback about their driving performance were tested with an on-road standardized evaluation before and after participating to a simulator training program (Feedback group. Their results were compared to a Control group (12 older drivers who received the same refresher course and in-simulator active practice as the Feedback group without receiving driving-specific feedback. Results After attending the training program, the Control group showed no increase in the frequency of the visual inspection of three regions of interests (rear view and left side mirrors, and blind spot. In contrast, for the Feedback group, combining active training and driving-specific feedbacks increased the frequency of blind spot inspection by 100% (32.3 to 64.9% of verification before changing lanes. Conclusions These results suggest that simulator training combined with driving-specific feedbacks helped older drivers to improve their visual inspection strategies, and that in-simulator training transferred positively to on-road driving. In order to be effective, it is claimed that driving programs should include active practice sessions with driving-specific feedbacks. Simulators offer a unique environment for developing such programs adapted to older drivers' needs.

  13. Primary versus secondary drivers of foraging activity in sandeel schools (Ammodytes tobianus)

    DEFF Research Database (Denmark)

    Deurs, Mikael van; Behrens, Jane; Warnar, Thomas

    2011-01-01

    to fishery biologists and has consequences for a wide range of predators ranging from birds and mammals to commercially important species. However, experimental studies that shed light on the primary drivers of foraging activity in fish are rare. In the present study, whole schools of sandeel (A. tobianus...

  14. Handbook of driver assistance systems basic information, components and systems for active safety and comfort

    CERN Document Server

    Hakuli, Stephan; Lotz, Felix; Singer, Christina

    2016-01-01

    This fundamental work explains in detail systems for active safety and driver assistance, considering both their structure and their function. These include the well-known standard systems such as Anti-lock braking system (ABS), Electronic Stability Control (ESC) or Adaptive Cruise Control (ACC). But it includes also new systems for protecting collisions protection, for changing the lane, or for convenient parking. The book aims at giving a complete picture focusing on the entire system. First, it describes the components which are necessary for assistance systems, such as sensors, actuators, mechatronic subsystems, and control elements. Then, it explains key features for the user-friendly design of human-machine interfaces between driver and assistance system. Finally, important characteristic features of driver assistance systems for particular vehicles are presented: Systems for commercial vehicles and motorcycles.

  15. Effects of irregular-shift work and physical activity on cardiovascular risk factors in truck drivers

    Directory of Open Access Journals (Sweden)

    Elaine Cristina Marqueze

    2013-06-01

    Full Text Available OBJECTIVE: To analyze the putative effect of type of shift and its interaction with leisure-time physical activity on cardiovascular risk factors in truck drivers. METHODS: A cross-sectional study was undertaken on 57 male truck drivers working at a transportation company, of whom 31 worked irregular shifts and 26 worked on the day-shift. Participants recorded their physical activity using the International Physical Activity Questionnaire along with measurements of blood pressure, body mass index and waist-hip ratio. Participants also provided a fasting blood sample for analysis of lipid-related outcomes. Data were analyzed using a factorial model which was covariate-controlled for age, smoking, work demand, control at work and social support. RESULTS: Most of the irregular-shift and day-shift workers worked more than 8 hours per day (67.7% and 73.1%, respectively. The mean duration of experience working the irregular schedule was 15.7 years. Day-shift workers had never engaged in irregular-shift work and had been working as a truck driver for 10.8 years on average. The irregular-shift drivers had lower work demand but less control compared to day-shift drivers (p < 0.05. Moderately-active irregular-shift workers had higher systolic and diastolic arterial pressures (143.7 and 93.2 mmHg, respectively than moderately-active day-shift workers (116 and 73.3 mmHg, respectively (p < 0.05 as well as higher total cholesterol concentrations (232.1 and 145 mg/dl, respectively (p = 0.01. Irrespective of their physical activity, irregular-shift drivers had higher total cholesterol and LDL-cholesterol concentrations (211.8 and 135.7 mg/dl, respectively than day-shift workers (161.9 and 96.7 mg/dl, respectively (ANCOVA, p < 0.05. CONCLUSIONS: Truck drivers are exposed to cardiovascular risk factors due to the characteristics of the job, such as high work demand, long working hours and time in this profession, regardless of shift type or leisure-time physical

  16. Stochastic ion channel gating in dendritic neurons: morphology dependence and probabilistic synaptic activation of dendritic spikes.

    Directory of Open Access Journals (Sweden)

    Robert C Cannon

    Full Text Available Neuronal activity is mediated through changes in the probability of stochastic transitions between open and closed states of ion channels. While differences in morphology define neuronal cell types and may underlie neurological disorders, very little is known about influences of stochastic ion channel gating in neurons with complex morphology. We introduce and validate new computational tools that enable efficient generation and simulation of models containing stochastic ion channels distributed across dendritic and axonal membranes. Comparison of five morphologically distinct neuronal cell types reveals that when all simulated neurons contain identical densities of stochastic ion channels, the amplitude of stochastic membrane potential fluctuations differs between cell types and depends on sub-cellular location. For typical neurons, the amplitude of membrane potential fluctuations depends on channel kinetics as well as open probability. Using a detailed model of a hippocampal CA1 pyramidal neuron, we show that when intrinsic ion channels gate stochastically, the probability of initiation of dendritic or somatic spikes by dendritic synaptic input varies continuously between zero and one, whereas when ion channels gate deterministically, the probability is either zero or one. At physiological firing rates, stochastic gating of dendritic ion channels almost completely accounts for probabilistic somatic and dendritic spikes generated by the fully stochastic model. These results suggest that the consequences of stochastic ion channel gating differ globally between neuronal cell-types and locally between neuronal compartments. Whereas dendritic neurons are often assumed to behave deterministically, our simulations suggest that a direct consequence of stochastic gating of intrinsic ion channels is that spike output may instead be a probabilistic function of patterns of synaptic input to dendrites.

  17. Structure of product-bound SMG1 lipase: active site gating implications.

    Science.gov (United States)

    Guo, Shaohua; Xu, Jinxin; Pavlidis, Ioannis V; Lan, Dongming; Bornscheuer, Uwe T; Liu, Jinsong; Wang, Yonghua

    2015-12-01

    Monoacylglycerol and diacylglycerol lipases are industrially interesting enzymes, due to the health benefits that arise from the consumption of diglycerides compared to the traditional triglyceride oils. Most lipases possess an α-helix (lid) directly over the catalytic pocket which regulates the activity of the enzyme. Generally, lipases exist in active and inactive conformations, depending on the positioning of this lid subdomain. However, lipase SMG1, a monoacylglycerol and diacylglycerol specific lipase, has an atypical activation mechanism. In the present study we were able to prove by crystallography, in silico analysis and activity tests that only two positions, residues 102 and 278, are responsible for a gating mechanism that regulates the active and inactive states of the lipase, and that no significant structural changes take place during activation except for oxyanion hole formation. The elucidation of the gating effect provided data enabling the rational design of improved lipases with 6-fold increase in the hydrolytic activity toward diacylglycerols, just by providing additional substrate stabilization with a single mutation (F278N or F278T). Due to the conservation of F278 among the monoacylglycerol and diacylglycerol lipases in the Rhizomucor miehei lipase-like family, the gating mechanism described herein might represent a general mechanism applicable to other monoacylglycerol and diacylglycerol lipases as well. Database: Structural data are available in the Protein Data Bank under the accession numbers 4ZRE (F278D mutant) and 4ZRD (F278N mutant).

  18. Characteristics and drivers of venture capital investment activity in Romania

    Directory of Open Access Journals (Sweden)

    Mihaela DIACONU

    2012-07-01

    Full Text Available The present paper aims at characterising the venture capital market and identifying factors affecting the venture capital investments activity in Romania in the period 2000-2010. With a view to assessing the intensity of manifestation of various factors on the supply and demand of venture capital we use an econometric model of macroeconomic variables already tested in the literature. We consider, however, that we bring contributions to the approach, by analysing the features of the venture capital market in Romania and impact factors, our work being, at the same time, support in assessing the types of decisions to be adopted by policymakers to the formation of an authentic market and stimulating innovation. Our results indicate that the total R&D intensity is the main determinant of the venture capitals invested in this period in the two phases (for early stages and expansion. A significant incidence, mainly on the supply side, also shows the annual long term real interest rate, while the market capitalisation, the effective marginal tax rate on corporate income, the annual inflation or unemployment rate do not impact on the venture capital. Our recommendations, in terms of formation and development of the venture capital market, look as a priority, strengthening the demand for resources, respectively encouraging of enterprises to innovate, creating of conditions for the supply to be manifested in the seed and start-up stages and the compatibilization of the need for resources with prudential rules by adapting regulations for institutional investors.

  19. Forecasting the Solar Drivers of Severe Space Weather from Active-Region Magnetograms

    Science.gov (United States)

    Falconer, David A.; Moore, Ronald L.; Barghouty, Abdulnasser F.; Khazanov, Igor

    2012-01-01

    Solar drivers of severe space weather can be predicted from line-of-sight magnetograms, via a free-energy proxy measured from the neutral lines. This can be done in near real time. In addition to depending strongly on the free magnetic energy, an active region's chance of having a major eruption depends strongly on other aspects of the evolving magnetic field (e.g., its complexity and flux emergence).

  20. Activity of Palythoa caribaeorum Venom on Voltage-Gated Ion Channels in Mammalian Superior Cervical Ganglion Neurons

    Directory of Open Access Journals (Sweden)

    Fernando Lazcano-Pérez

    2016-05-01

    Full Text Available The Zoanthids are an order of cnidarians whose venoms and toxins have been poorly studied. Palythoa caribaeorum is a zoanthid commonly found around the Mexican coastline. In this study, we tested the activity of P. caribaeorum venom on voltage-gated sodium channel (NaV1.7, voltage-gated calcium channel (CaV2.2, the A-type transient outward (IA and delayed rectifier (IDR currents of KV channels of the superior cervical ganglion (SCG neurons of the rat. These results showed that the venom reversibly delays the inactivation process of voltage-gated sodium channels and inhibits voltage-gated calcium and potassium channels in this mammalian model. The compounds responsible for these effects seem to be low molecular weight peptides. Together, these results provide evidence for the potential use of zoanthids as a novel source of cnidarian toxins active on voltage-gated ion channels.

  1. Active inductor shunt peaking in high-speed VCSEL driver design

    CERN Document Server

    Liang, Futian; Hou, Suen; Liu, Chonghan; Liu, Tiankuan; Su, Da-Shung; Teng, Ping-Kun; Xiang, Annie; Ye, Jingbo; Jin, Ge

    2013-01-01

    An all transistor active inductor shunt peaking structure has been used in a prototype of 8-Gbps high-speed VCSEL driver which is designed for the optical link in ATLAS liquid Argon calorimeter upgrade. The VCSEL driver is fabricated in a commercial 0.25-um Silicon-on-Sapphire (SoS) CMOS process for radiation tolerant purpose. The all transistor active inductor shunt peaking is used to overcome the bandwidth limitation from the CMOS process. The peaking structure has the same peaking effect as the passive one, but takes a small area, does not need linear resistors and can overcome the process variation by adjust the peaking strength via an external control. The design has been tapped out, and the prototype has been proofed by the preliminary electrical test results and bit error ratio test results. The driver achieves 8-Gbps data rate as simulated with the peaking. We present the all transistor active inductor shunt peaking structure, simulation and test results in this paper.

  2. Impact of echo broadening effect on active range-gated imaging

    Institute of Scientific and Technical Information of China (English)

    Xinwei Wang; Yan Zhou; Yuliang Liu

    2012-01-01

    Analytical formulas and experimental proof of the echo broadening effect in active range-gated imaging,including atmospheric interference,currently exist.We investigate the impact of this effect on target detection.Our research demonstrates that the echo broadening effect affects the energy profile of the depth of view and collects only part of the signals of targets in head and tail zones.Under bad weather conditions,the effect weakens the signal-to-noise ratio (SNR) of images,especially in cases with large laser pulse width.Fortunately,by modifying the laser pulse width,the effect can be controlled.These results are valuable to the applications of active range-gated imaging.

  3. Stress and CRF gate neural activation of BDNF in the mesolimbic reward pathway.

    Science.gov (United States)

    Walsh, Jessica J; Friedman, Allyson K; Sun, Haosheng; Heller, Elizabeth A; Ku, Stacy M; Juarez, Barbara; Burnham, Veronica L; Mazei-Robison, Michelle S; Ferguson, Deveroux; Golden, Sam A; Koo, Ja Wook; Chaudhury, Dipesh; Christoffel, Daniel J; Pomeranz, Lisa; Friedman, Jeffrey M; Russo, Scott J; Nestler, Eric J; Han, Ming-Hu

    2014-01-01

    Mechanisms controlling release of brain-derived neurotrophic factor (BDNF) in the mesolimbic dopamine reward pathway remain unknown. We report that phasic optogenetic activation of this pathway increases BDNF amounts in the nucleus accumbens (NAc) of socially stressed mice but not of stress-naive mice. This stress gating of BDNF signaling is mediated by corticotrophin-releasing factor (CRF) acting in the NAc. These results unravel a stress context-detecting function of the brain's mesolimbic circuit.

  4. Trends and drivers of fire activity vary across California aridland ecosystems

    Science.gov (United States)

    Syphard, Alexandra D.; Keeley, Jon E.; Abatzoglou, John T.

    2017-01-01

    Fire activity has increased in western US aridland ecosystems due to increased human-caused ignitions and the expansion of flammable exotic grasses. Because many desert plants are not adapted to fire, increased fire activity may have long-lasting ecological impacts on native vegetation and the wildlife that depend on it. Given the heterogeneity across aridland ecosystems, it is important to understand how trends and drivers of fire vary, so management can be customized accordingly. We examined historical trends and quantified the relative importance of and interactions among multiple drivers of fire patterns across five aridland ecoregions in southeastern California from 1970 to 2010. Fire frequency increased across all ecoregions for the first couple decades, and declined or plateaued since the 1990s; but area burned continued to increase in some regions. The relative importance of anthropogenic and biophysical drivers varied across ecoregions, with both direct and indirect influences on fire. Anthropogenic variables were equally important as biophysical variables, but some contributed indirectly, presumably via their influence on annual grass distribution and abundance. Grass burned disproportionately more than other cover types, suggesting that addressing exotics may be the key to fire management and conservation in much of the area.

  5. Robust control design for active driver assistance systems a linear-parameter-varying approach

    CERN Document Server

    Gáspár, Péter; Bokor, József; Nemeth, Balazs

    2017-01-01

    This monograph focuses on control methods that influence vehicle dynamics to assist the driver in enhancing passenger comfort, road holding, efficiency and safety of transport, etc., while maintaining the driver’s ability to override that assistance. On individual-vehicle-component level the control problem is formulated and solved by a unified modelling and design method provided by the linear parameter varying (LPV) framework. The global behaviour desired is achieved by a judicious interplay between the individual components, guaranteed by an integrated control mechanism. The integrated control problem is also formalized and solved in the LPV framework. Most important among the ideas expounded in the book are: application of the LPV paradigm in the modelling and control design methodology; application of the robust LPV design as a unified framework for setting control tasks related to active driver assistance; formulation and solution proposals for the integrated vehicle control problem; proposal for a re...

  6. Low voltage driven dielectric electro active polymer actuator with integrated piezoelectric transformer based driver

    DEFF Research Database (Denmark)

    Andersen, Thomas; Rødgaard, Martin Schøler; Thomsen, Ole Cornelius

    2011-01-01

    Today’s Dielectric Electro Active Polymer (DEAP) actuators utilize high voltage (HV) in the range of kilo volts to fully stress the actuator. The requirement of HV is a drawback for the general use in the industry due to safety concerns and HV regulations. In order to avoid the HV interface to DEAP...... actuators, a low voltage solution is developed by integrating the driver electronic into a 110 mm tall cylindrical coreless Push InLastor actuator. To decrease the size of the driver, a piezoelectric transformer (PT) based solution is utilized. The PT is essentially an improved Rosen type PT...... with interleaved sections. Furthermore, the PT is optimized for an input voltage of 24 V with a gain high enough to achieve a DEAP voltage of 2.5 kV. The PT is simulated and verified through measurements on a working prototype. With the adapted hysteretic based control system; output voltage wave forms of both...

  7. Photocontrol of Voltage-Gated Ion Channel Activity by Azobenzene Trimethylammonium Bromide in Neonatal Rat Cardiomyocytes.

    Directory of Open Access Journals (Sweden)

    Sheyda R Frolova

    Full Text Available The ability of azobenzene trimethylammonium bromide (azoTAB to sensitize cardiac tissue excitability to light was recently reported. The dark, thermally relaxed trans- isomer of azoTAB suppressed spontaneous activity and excitation propagation speed, whereas the cis- isomer had no detectable effect on the electrical properties of cardiomyocyte monolayers. As the membrane potential of cardiac cells is mainly controlled by activity of voltage-gated ion channels, this study examined whether the sensitization effect of azoTAB was exerted primarily via the modulation of voltage-gated ion channel activity. The effects of trans- and cis- isomers of azoTAB on voltage-dependent sodium (INav, calcium (ICav, and potassium (IKv currents in isolated neonatal rat cardiomyocytes were investigated using the whole-cell patch-clamp technique. The experiments showed that azoTAB modulated ion currents, causing suppression of sodium (Na+ and calcium (Ca2+ currents and potentiation of net potassium (K+ currents. This finding confirms that azoTAB-effect on cardiac tissue excitability do indeed result from modulation of voltage-gated ion channels responsible for action potential.

  8. Structural basis for the coupling between activation and inactivation gates in K+ channels

    Science.gov (United States)

    Cuello, Luis G.; Jogini, Vishwanath; Cortes, D. Marien.; Pan, Albert C; Gagnon, Dominique G.; Dalmas, Olivier; Cordero-Morales, Julio F.; Chakrapani, Sudha; Roux, Benoit; Perozo, Eduardo

    2011-01-01

    The coupled interplay between activation and inactivation gating is a functional hallmark of K+ channels1,2. This coupling has been experimentally demonstrated from ion interaction effects3,4, cysteine accessibility1 and is associated with a well-defined boundary of energetically coupled residues2. The structure of KcsA in its fully open conformation, as well as four other partial openings, richly illustrates the structural basis of activation-inactivation gating5. Here, we have identified the mechanistic principles by which movements on the inner bundle gate trigger conformational changes at the selectivity filter, leading to the non-conductive C-type inactivated state. Analysis of a series of KcsA open structures suggests that as a consequence of the hinge bending and rotation of TM2, the aromatic ring of Phe103 tilts towards residues Thr74 and Thr75 in the pore helix as well as Ile100 in the neighboring subunit. This allows the network of hydrogen bonds among residues W67, E71, and D80 to destabilize the selectivity filter6,7, facilitating entry to its non-conductive conformation. Mutations at position 103, affect gating kinetics in a size-dependent way: small side chain substitutions F103A and F103C severely impair inactivation kinetics, while larger side chains (F103W) have more subtle effects. This suggests that the allosteric coupling between the inner helical bundle and the selectivity filter might rely on straightforward mechanical deformation propagated through a network of steric contacts. Average interactions calculated from molecular dynamics simulations show favourable open state interaction-energies between Phe103 and surrounding residues. Similar interactions were probed in the Shaker K-channel where inactivation was impaired in the mutant I470A. We propose that side chain rearrangements at position 103 mechanically couple activation and inactivation in KcsA and a variety of other K channels. PMID:20613845

  9. Structural basis for the coupling between activation and inactivation gates in K[superscript +] channels

    Energy Technology Data Exchange (ETDEWEB)

    Cuello, Luis G.; Jogini, Vishwanath; Cortes, D. Marien; Pan, Albert C.; Gagnon, Dominique G.; Dalmas, Olivier; Cordero-Morales, Julio F.; Chakrapani, Sudha; Roux, Benoît; Perozo, Eduardo (UC)

    2010-08-30

    The coupled interplay between activation and inactivation gating is a functional hallmark of K{sup +} channels. This coupling has been experimentally demonstrated through ion interaction effects and cysteine accessibility, and is associated with a well defined boundary of energetically coupled residues. The structure of the K{sup +} channel KcsA in its fully open conformation, in addition to four other partial channel openings, richly illustrates the structural basis of activation-inactivation gating. Here, we identify the mechanistic principles by which movements on the inner bundle gate trigger conformational changes at the selectivity filter, leading to the non-conductive C-type inactivated state. Analysis of a series of KcsA open structures suggests that, as a consequence of the hinge-bending and rotation of the TM2 helix, the aromatic ring of Phe103 tilts towards residues Thr74 and Thr75 in the pore-helix and towards Ile100 in the neighbouring subunit. This allows the network of hydrogen bonds among residues Trp67, Glu71 and Asp80 to destabilize the selectivity filter, allowing entry to its non-conductive conformation. Mutations at position 103 have a size-dependent effect on gating kinetics: small side-chain substitutions F103A and F103C severely impair inactivation kinetics, whereas larger side chains such as F103W have more subtle effects. This suggests that the allosteric coupling between the inner helical bundle and the selectivity filter might rely on straightforward mechanical deformation propagated through a network of steric contacts. Average interactions calculated from molecular dynamics simulations show favourable open-state interaction-energies between Phe103 and the surrounding residues. We probed similar interactions in the Shaker K{sup +} channel where inactivation was impaired in the mutant I470A. We propose that side-chain rearrangements at position 103 mechanically couple activation and inactivation in KcsA and a variety of other K

  10. Structural basis for the coupling between activation and inactivation gates in K(+) channels.

    Science.gov (United States)

    Cuello, Luis G; Jogini, Vishwanath; Cortes, D Marien; Pan, Albert C; Gagnon, Dominique G; Dalmas, Olivier; Cordero-Morales, Julio F; Chakrapani, Sudha; Roux, Benoît; Perozo, Eduardo

    2010-07-08

    The coupled interplay between activation and inactivation gating is a functional hallmark of K(+) channels. This coupling has been experimentally demonstrated through ion interaction effects and cysteine accessibility, and is associated with a well defined boundary of energetically coupled residues. The structure of the K(+) channel KcsA in its fully open conformation, in addition to four other partial channel openings, richly illustrates the structural basis of activation-inactivation gating. Here, we identify the mechanistic principles by which movements on the inner bundle gate trigger conformational changes at the selectivity filter, leading to the non-conductive C-type inactivated state. Analysis of a series of KcsA open structures suggests that, as a consequence of the hinge-bending and rotation of the TM2 helix, the aromatic ring of Phe 103 tilts towards residues Thr 74 and Thr 75 in the pore-helix and towards Ile 100 in the neighbouring subunit. This allows the network of hydrogen bonds among residues Trp 67, Glu 71 and Asp 80 to destabilize the selectivity filter, allowing entry to its non-conductive conformation. Mutations at position 103 have a size-dependent effect on gating kinetics: small side-chain substitutions F103A and F103C severely impair inactivation kinetics, whereas larger side chains such as F103W have more subtle effects. This suggests that the allosteric coupling between the inner helical bundle and the selectivity filter might rely on straightforward mechanical deformation propagated through a network of steric contacts. Average interactions calculated from molecular dynamics simulations show favourable open-state interaction-energies between Phe 103 and the surrounding residues. We probed similar interactions in the Shaker K(+) channel where inactivation was impaired in the mutant I470A. We propose that side-chain rearrangements at position 103 mechanically couple activation and inactivation in KcsA and a variety of other K(+) channels.

  11. FORMALIZATION OF LOCOMOTIVE DRIVER ACTIVITY TENSION INDICATOR BASED ON THE ERGONOMIC MODEL

    Directory of Open Access Journals (Sweden)

    O. M. Horobchenko

    2017-02-01

    Full Text Available Purpose. A key factor contributing to the safety and quality of ergatic system "train-driver" is the intensity of the locomotive crew’s work. The aim of this work is formalization of locomotive driver activity tension indicator. Methodology. One of the characteristics of driver activity tension is the difference between the time allotted to complete the task, and the necessary (external reserve or deficiency time. The sets of major and minor operations in the management of the train locomotive in different train situations were identified. Using the methods of fuzzy logic, the concept of "materiality of the operation of the locomotive control" is presented in the form of a set of linguistic variables. To determine the function membership of the elements of the set "the importance of the operation of the locomotive control" the method of expert evaluations was used. Coefficient of temporary tension is presented in the form of fuzzy number L-R-type. Findings. It was found the value of the relative number of operations of locomotive control according to the distribution using the parameter of operation "importance". To determine the most tensioned mode of the driver ranking the traffic condition according to the parameter of relative amounts of the important management operations was conducted. The most difficult modes are the "front hindrance", "movement in unfavorable weather conditions" and "departure from the station to the running line". Originality. The introduction of the value "conventional importance of the operation" allowed us to more accurately describe the terms of train driving. For the first time the work presents determination of tension of the driver’s work in the form of a unimodal fuzzy number, which will make it possible to use the methods of the theory of artificial intelligence to simulate activity of the locomotive driver and develop intelligent control systems. Practical value. There were obtained the opportunity to

  12. Physiological investigation of automobile driver's activation index using simulated monotonous driving.

    Science.gov (United States)

    Yamakoshi, T; Yamakoshi, K; Tanaka, S; Nogawa, M; Kusakabe, M; Kusumi, M; Tanida, K

    2004-01-01

    Monotonous automobile operation in our daily life may cause the lowering of what might be termed an activation state of the human body, resulting in an increased risk of an accident. We therefore propose to create a more suitable environment in-car so as to allow active operation of the vehicle, hopefully thus avoiding potentially dangerous situations during driving. In order to develop such an activation method as a final goal, we have firstly focused on the acquisition of physiological variables, including cardiovascular parameters, during presentation to the driver of a monotonous screen image, simulating autonomous travel of constant-speed on a motorway. Subsequently, we investigated the derivation of a driver's activation index. During the screen image presentation, a momentary electrical stimulation of about 1 second duration was involuntarily applied to a subject's shoulder to obtain a physiological response. We have successfully monitored various physiological variables during the image presentation, and results suggest that a peculiar pattern in the beat-by-beat change of blood pressure in response to the involuntary stimulus may be an appropriate, and feasible, index relevant to activation state.

  13. Hysteresis of KcsA potassium channel's activation- deactivation gating is caused by structural changes at the channel's selectivity filter.

    Science.gov (United States)

    Tilegenova, Cholpon; Cortes, D Marien; Cuello, Luis G

    2017-03-21

    Mode-shift or hysteresis has been reported in ion channels. Voltage-shift for gating currents is well documented for voltage-gated cation channels (VGCC), and it is considered a voltage-sensing domain's (VSD) intrinsic property. However, uncoupling the Shaker K(+) channel's pore domain (PD) from the VSD prevented the mode-shift of the gating currents. Consequently, it was proposed that an open-state stabilization of the PD imposes a mechanical load on the VSD, which causes its mode-shift. Furthermore, the mode-shift displayed by hyperpolarization-gated cation channels is likely caused by structural changes at the channel's PD similar to those underlying C-type inactivation. To demonstrate that the PD of VGCC undergoes hysteresis, it is imperative to study its gating process in the absence of the VSD. A back-door strategy is to use KcsA (a K(+) channel from the bacteria Streptomyces lividans) as a surrogate because it lacks a VSD and exhibits an activation coupled to C-type inactivation. By directly measuring KcsA's activation gate opening and closing in conditions that promote or halt C-type inactivation, we have found (i) that KcsA undergoes mode-shift of gating when having K(+) as the permeant ion; (ii) that Cs(+) or Rb(+), known to halt C-inactivation, prevented mode-shift of gating; and (iii) that, in the total absence of C-type inactivation, KcsA's mode-shift was prevented. Finally, our results demonstrate that an allosteric communication causes KcsA's activation gate to "remember" the conformation of the selectivity filter, and hence KcsA requires a different amount of energy for opening than for closing.

  14. Considerations on the implementation and modeling of an active mass driver with electric torsional servomotor

    Science.gov (United States)

    Ubertini, Filippo; Venanzi, Ilaria; Comanducci, Gabriele

    2015-06-01

    The current trend in full-scale applications of active mass drivers for mitigating buildings' vibrations is to rely on the use of electric servomotors and low friction transmission devices. While similar full-scale applications have been recently documented, there is still the need for deepening the understanding of the behavior of such active mass drivers, especially as it concerns their reliability in the case of extreme loading events. This paper presents some considerations arisen in the physical implementation of a prototype active mass driver system, fabricated by coupling an electric torsional servomotor with a ball screw transmission device, using state-of-the-art electronics and a high speed digital communication protocol between controller and servomotor drive. The prototype actuator is mounted on top of a scaled-down five-story frame structure, subjected to base excitation provided by a sliding table actuated by an electrodynamic shaker. The equations of motion are rigorously derived, at first, by considering the torque of the servomotor as the control input, in agreement with other literature work. Then, they are extended to the case where the servomotor operates under kinematic control, that is, by commanding its angular velocity instead of its torque, including control-structure-interaction effects. Experiments are carried out by employing an inherently stable collocated skyhook control algorithm, proving, on the one hand, the control effectiveness of the device but also revealing, on the other hand, the possibility of closed-loop system instability at high gains. Theoretical interpretation of the results clarifies that the dynamic behavior of the actuator plays a central role in determining its control effectiveness and is responsible for the observed stability issues, operating similarly to time delay effects. Numerical extension to the case of earthquake excitation confirms the control effectiveness of the device and highlights that different

  15. Seasonal prediction of lightning activity in North Western Venezuela: Large-scale versus local drivers

    Science.gov (United States)

    Muñoz, Á. G.; Díaz-Lobatón, J.; Chourio, X.; Stock, M. J.

    2016-05-01

    The Lake Maracaibo Basin in North Western Venezuela has the highest annual lightning rate of any place in the world (~ 200 fl km- 2 yr- 1), whose electrical discharges occasionally impact human and animal lives (e.g., cattle) and frequently affect economic activities like oil and natural gas exploitation. Lightning activity is so common in this region that it has a proper name: Catatumbo Lightning (plural). Although short-term lightning forecasts are now common in different parts of the world, to the best of the authors' knowledge, seasonal prediction of lightning activity is still non-existent. This research discusses the relative role of both large-scale and local climate drivers as modulators of lightning activity in the region, and presents a formal predictability study at seasonal scale. Analysis of the Catatumbo Lightning Regional Mode, defined in terms of the second Empirical Orthogonal Function of monthly Lightning Imaging Sensor (LIS-TRMM) and Optical Transient Detector (OTD) satellite data for North Western South America, permits the identification of potential predictors at seasonal scale via a Canonical Correlation Analysis. Lightning activity in North Western Venezuela responds to well defined sea-surface temperature patterns (e.g., El Niño-Southern Oscillation, Atlantic Meridional Mode) and changes in the low-level meridional wind field that are associated with the Inter-Tropical Convergence Zone migrations, the Caribbean Low Level Jet and tropical cyclone activity, but it is also linked to local drivers like convection triggered by the topographic configuration and the effect of the Maracaibo Basin Nocturnal Low Level Jet. The analysis indicates that at seasonal scale the relative contribution of the large-scale drivers is more important than the local (basin-wide) ones, due to the synoptic control imposed by the former. Furthermore, meridional CAPE transport at 925 mb is identified as the best potential predictor for lightning activity in the Lake

  16. p53 activated by AND gate genetic circuit under radiation and hypoxia for targeted cancer gene therapy.

    Science.gov (United States)

    Ding, Miao; Li, Rong; He, Rong; Wang, Xingyong; Yi, Qijian; Wang, Weidong

    2015-09-01

    Radio-activated gene therapy has been developed as a novel therapeutic strategy against cancer; however, expression of therapeutic gene in peritumoral tissues will result in unacceptable toxicity to normal cells. To restrict gene expression in targeted tumor mass, we used hypoxia and radiation tolerance features of tumor cells to develop a synthetic AND gate genetic circuit through connecting radiation sensitivity promoter cArG6 , heat shock response elements SNF1, HSF1 and HSE4 with retroviral vector plxsn. Their construction and dynamic activity process were identified through downstream enhanced green fluorescent protein and wtp53 expression in non-small cell lung cancer A549 cells and in a nude mice model. The result showed that AND gate genetic circuit could be activated by lower required radiation dose (6 Gy) and after activated, AND gate could induce significant apoptosis effects and growth inhibition of cancer cells in vitro and in vivo. The radiation- and hypoxia-activated AND gate genetic circuit, which could lead to more powerful target tumoricidal activity represented a promising strategy for both targeted and effective gene therapy of human lung adenocarcinoma and low dose activation character of the AND gate genetic circuit implied that this model could be further exploited to decrease side-effects of clinical radiation therapy.

  17. The Relationship between Logistics Sophistication and Drivers of the Outsourcing of Logistics Activities

    Directory of Open Access Journals (Sweden)

    Peter Wanke

    2008-10-01

    Full Text Available A strong link has been established between operational excellence and the degree of sophistication of logistics organization, a function of factors such as performance monitoring, investment in Information Technology [IT] and the formalization of logistics organization, as proposed in the Bowersox, Daugherty, Dröge, Germain and Rogers (1992 Leading Edge model. At the same time, shippers have been increasingly outsourcing their logistics activities to third party providers. This paper, based on a survey with large Brazilian shippers, addresses a gap in the literature by investigating the relationship between dimensions of logistics organization sophistication and drivers of logistics outsourcing. To this end, the dimensions behind the logistics sophistication construct were first investigated. Results from factor analysis led to the identification of six dimensions of logistics sophistication. By means of multivariate logistical regression analyses it was possible to relate some of these dimensions, such as the formalization of the logistics organization, to certain drivers of the outsourcing of logistics activities of Brazilian shippers, such as cost savings. These results indicate the possibility of segmenting shippers according to characteristics of their logistics organization, which may be particularly useful to logistics service providers.

  18. Lifestyle counseling in overweight truck and bus drivers - Effects on dietary patterns and physical activity.

    Science.gov (United States)

    Puhkala, Jatta; Kukkonen-Harjula, Katriina; Aittasalo, Minna; Mansikkamäki, Kirsi; Partinen, Markku; Hublin, Christer; Kärmeniemi, Paula; Sallinen, Mikael; Olkkonen, Seppo; Tokola, Kari; Ojala, Anna; Nygård, Clas-Håkan; Fogelholm, Mikael

    2016-12-01

    We studied dietary patterns, physical activity (PA), and monthly goal setting in a weight reduction intervention in long-distance professional drivers. The study was conducted in Finland in 2009-2012. Male drivers with waist circumference > 100 cm were randomized to a lifestyle counseling (LIFE, N = 55) and a reference (REF, N = 58) group. During 12 months, LIFE participated in 6 face-to-face and 7 telephone counseling sessions on diet and PA. Dietary patterns were assessed using an index combining food diary and counselor interview, and PA with the number of daily steps using a pedometer. Monthly lifestyle goals, perceived facilitators and barriers, and adverse effects of PA in the LIFE participants were monitored using counselors' log books. Forty-seven (85%) LIFE participants completed the 12-month program. After 12 months, the mean dietary index score improved by 12% (p = 0.002, N = 24), and the number of daily steps increased by 1811 steps (median; p = 0.01, N = 22). The most frequent dietary goals dealt with meal frequency, plate model, and intake of vegetables, fruits, and berries. The most common PA mode was walking. Typical facilitators to reach monthly lifestyle goals were support from family and friends and ailment prevention; typical barriers were working schedules and ailments. Adverse effects, most commonly musculoskeletal pain, occurred among 83% of the LIFE participants. Positive changes in lifestyle habits were observed during counseling. Monthly lifestyle counseling combining face-to-face and phone contacts seemed appropriate to long-distance drivers. Barriers for reaching lifestyle changes, and adverse effects of PA were common and need to be addressed when planning counseling. Clinical Trials NCT00893646.

  19. Stochastically gating ion channels enable patterned spike firing through activity-dependent modulation of spike probability.

    Directory of Open Access Journals (Sweden)

    Joshua T Dudman

    2009-02-01

    Full Text Available The transformation of synaptic input into patterns of spike output is a fundamental operation that is determined by the particular complement of ion channels that a neuron expresses. Although it is well established that individual ion channel proteins make stochastic transitions between conducting and non-conducting states, most models of synaptic integration are deterministic, and relatively little is known about the functional consequences of interactions between stochastically gating ion channels. Here, we show that a model of stellate neurons from layer II of the medial entorhinal cortex implemented with either stochastic or deterministically gating ion channels can reproduce the resting membrane properties of stellate neurons, but only the stochastic version of the model can fully account for perithreshold membrane potential fluctuations and clustered patterns of spike output that are recorded from stellate neurons during depolarized states. We demonstrate that the stochastic model implements an example of a general mechanism for patterning of neuronal output through activity-dependent changes in the probability of spike firing. Unlike deterministic mechanisms that generate spike patterns through slow changes in the state of model parameters, this general stochastic mechanism does not require retention of information beyond the duration of a single spike and its associated afterhyperpolarization. Instead, clustered patterns of spikes emerge in the stochastic model of stellate neurons as a result of a transient increase in firing probability driven by activation of HCN channels during recovery from the spike afterhyperpolarization. Using this model, we infer conditions in which stochastic ion channel gating may influence firing patterns in vivo and predict consequences of modifications of HCN channel function for in vivo firing patterns.

  20. Dysfunctional Hyperpolarization-Activated Cyclic Nucleotide-gated Ion Channels in Cardiac Diseases

    Directory of Open Access Journals (Sweden)

    Xiaoqi Zhao

    Full Text Available Abstract Hyperpolarization-activated cyclic nucleotide-gated (HCN channels are reverse voltage-dependent, and their activation depends on the hyperpolarization of the membrane and may be directly or indirectly regulated by the cyclic adenosine monophosphate (cAMP or other signal-transduction cascades. The distribution, quantity and activation states of HCN channels differ in tissues throughout the body. Evidence exhibits that HCN channels play critical roles in the generation and conduction of the electrical impulse and the physiopathological process of some cardiac diseases. They may constitute promising drug targets in the treatment of these cardiac diseases. Pharmacological treatment targeting HCN channels is of benefit to these cardiac conditions.

  1. The expression of CD123 can decrease with basophil activation: implications for the gating strategy of the basophil activation test

    OpenAIRE

    Santos, Alexandra F.; Bécares, Natalia; Stephens, Alick; Turcanu, Victor; Lack, Gideon

    2016-01-01

    Background Basophil activation test (BAT) reproduces IgE-mediated allergic reactions in vitro and has been used as a diagnostic test. Different markers can be used to identify basophils in whole blood and have implications for the outcome of the test. We aimed to assess changes in the expression of CD123 and HLA-DR following basophil activation and to select the best gating strategy for BAT using these markers. Methods BAT was performed in whole blood from 116 children. Peanut extract, anti-I...

  2. Fault Tolerant Operation of ISOP Multicell Dc-Dc Converter Using Active Gate Controlled SiC Protection Switch

    Directory of Open Access Journals (Sweden)

    Yusuke Hayashi

    2016-01-01

    Full Text Available An active gate controlled semiconductor protection switch using SiC-MOSFET is proposed to achieve the fault tolerant operation of ISOP (Input Series and Output Parallel connected multicell dc-dc converter. The SiC-MOSFET with high temperature capability simplifies the configuration of the protection circuit, and its on-resistance control by the active gate controller realizes the smooth protection without the voltage and the current surges. The first laboratory prototype of the protection switch is fabricated by using a SiC-MOSFET with a high frequency buck chopper for the active gate controller. The effectiveness of the proposed protection switch is verified, taking the impact of the volume reduction into account.

  3. Electric-field and temperature dependence of the activation energy associated with gate induced drain leakage

    Science.gov (United States)

    Alnuaimi, Aaesha; Nayfeh, Ammar; Koldyaev, Victor

    2013-01-01

    We examined the effect of temperature and electric field on the activation energy (Ea) of gate-induced drain leakage (GIDL) of a MOSFET. The measured GIDL current shows a temperature dependence consistent with a non-tunneling mechanism. In the low-electric-field regime and for temperatures above 55 °C, Ea is about 0.4 eV and drops from 0.4 eV to 0.1 eV as the applied gate voltage goes below VFB in the accumulation direction (decreased for the n-channel MOSFET). This suggests that electron-hole-pair generation at Si/SiO2 interface traps (Dit), enhanced by the electric field (the Poole-Frenkel effect), dominates GIDL in that regime. For temperatures below 55 °C, Ea is less than 0.15 eV for both weak and strong electric fields and displays minimal temperature dependence, indicating inelastic trap-assisted tunneling or phonon-assisted tunneling from a trap. In the very strong-electric-field regime (>1 MV/cm), band-to-band tunneling is the dominant mechanism.

  4. Structural basis of slow activation gating in the cardiac IKs channel complex

    DEFF Research Database (Denmark)

    Strutz-Seebohm, Nathalie; Pusch, Michael; Wolf, Steffen

    2011-01-01

    of the voltage sensor domain S4 of KCNQ1 in a putative pre-open channel state. Formation of this state may induce slow activation gating, the pivotal characteristic of native cardiac I(Ks) channels. This new KCNQ1-KCNE1 model may become useful for dynamic modeling of disease-associated mutant I(Ks) channels.......Accessory ß-subunits of the KCNE gene family modulate the function of various cation channel a-subunits by the formation of heteromultimers. Among the most dramatic changes of biophysical properties of a voltage-gated channel by KCNEs are the effects of KCNE1 on KCNQ1 channels. KCNQ1 and KCNE1...... are believed to form nativeI(Ks) channels. Here, we characterize molecular determinants of KCNE1 interaction with KCNQ1 channels by scanning mutagenesis, double mutant cycle analysis, and molecular dynamics simulations. Our findings suggest that KCNE1 binds to the outer face of the KCNQ1 channel pore domain...

  5. Role of nitric oxide in activity control of mechanically gated ionic channels in cardiomyocytes: NO-donor study.

    Science.gov (United States)

    Kazanski, V E; Kamkin, A G; Makarenko, E Yu; Lysenko, N N; Sutiagin, P V; Bo, Tian; Kiseleva, I S

    2010-12-01

    Whole-cell ionic currents through mechanically gated channels (MGC) were recorded in isolated cardiomyocytes under voltage clamp conditions. In unstrained cells, NO donors SNAP and DEA-NO activated MGC and induced MG-like currents. In contrast, in stretched cells with activated MGC, these NO-donors inactivated and inhibited MGC.

  6. A dynamic model for a displacement amplified magnetostrictive driver for active mounts

    Science.gov (United States)

    Chakrabarti, Suryarghya; Dapino, Marcelo J.

    2010-05-01

    A magnetostrictive actuator with a hydraulic displacement amplification mechanism is designed to be used as a driver in active engine mounts. The dynamic response of the actuator is quantified in terms of the output displacement and the magnetostriction. Eddy current losses are modeled as a one-dimensional magnetic diffusion problem in cylindrical coordinates. The Jiles-Atherton model is used to describe the magnetization state of the material as a function of applied magnetic fields. Magnetostriction, which is modeled as a single-valued function of magnetization, provides an input to the mechanical model describing the system vibrations. Friction at the elastomeric seals is modeled using the LuGre (Lund-Grenoble) friction model for lubricated contacts. Results show that the model accurately describes the dynamic behavior of the actuator up to 500 Hz. An order analysis of the data and calculated responses shows that the model describes the fundamental and higher-order spectral components generated by the device.

  7. A Color LED Driver Implemented by the Active Clamp Forward Converter

    Directory of Open Access Journals (Sweden)

    C. H. Chang

    2013-03-01

    Full Text Available Because light emitting diodes (LEDs have the advantages of dc working voltage, high luminescent efficiency, shortignition time, high reliability and pollution free, they have substituted for incandescent bulbs and fluorescent lampsgradually. In order to simplify circuit complexity, an active clamp forward converter with the sequential color display(SCD control is proposed to drive red, green and blue (RGB LED arrays. The proposed converter has zero-voltageswitching (ZVS operations of both the main switch and the auxiliary switch, resulting in high system efficiency. DrivingRGB LED arrays sequentially by one converter can save components and reduce cost significantly. Additionally, thepulse-width modulation (PWM control is applied to achieve a large chromaticity variation. The circuit operations areanalyzed in detail and the circuit parameters are designed based on the practical considerations. Finally, an illustrativeexample is implemented to demonstrate the feasibility and validity of the proposed LED driver.

  8. Disrupted coupling of gating charge displacement to Na+ current activation for DIIS4 mutations in hypokalemic periodic paralysis.

    Science.gov (United States)

    Mi, Wentao; Rybalchenko, Volodymyr; Cannon, Stephen C

    2014-08-01

    Missense mutations at arginine residues in the S4 voltage-sensor domains of NaV1.4 are an established cause of hypokalemic periodic paralysis, an inherited disorder of skeletal muscle involving recurrent episodes of weakness in conjunction with low serum K(+). Expression studies in oocytes have revealed anomalous, hyperpolarization-activated gating pore currents in mutant channels. This aberrant gating pore conductance creates a small inward current at the resting potential that is thought to contribute to susceptibility to depolarization in low K(+) during attacks of weakness. A critical component of this hypothesis is the magnitude of the gating pore conductance relative to other conductances that are active at the resting potential in mammalian muscle: large enough to favor episodes of paradoxical depolarization in low K(+), yet not so large as to permanently depolarize the fiber. To improve the estimate of the specific conductance for the gating pore in affected muscle, we sequentially measured Na(+) current through the channel pore, gating pore current, and gating charge displacement in oocytes expressing R669H, R672G, or wild-type NaV1.4 channels. The relative conductance of the gating pore to that of the pore domain pathway for Na(+) was 0.03%, which implies a specific conductance in muscle from heterozygous patients of ∼ 10 µS/cm(2) or 1% of the total resting conductance. Unexpectedly, our data also revealed a substantial decoupling between gating charge displacement and peak Na(+) current for both R669H and R672G mutant channels. This decoupling predicts a reduced Na(+) current density in affected muscle, consistent with the observations that the maximal dV/dt and peak amplitude of the action potential are reduced in fibers from patients with R672G and in a knock-in mouse model of R669H. The defective coupling between gating charge displacement and channel activation identifies a previously unappreciated mechanism that contributes to the reduced

  9. Regulation of Voltage-Activated K(+) Channel Gating by Transmembrane β Subunits.

    Science.gov (United States)

    Sun, Xiaohui; Zaydman, Mark A; Cui, Jianmin

    2012-01-01

    Voltage-activated K(+) (K(V)) channels are important for shaping action potentials and maintaining resting membrane potential in excitable cells. K(V) channels contain a central pore-gate domain (PGD) surrounded by four voltage-sensing domains (VSDs). The VSDs will change conformation in response to alterations of the membrane potential thereby inducing the opening of the PGD. Many K(V) channels are heteromeric protein complexes containing auxiliary β subunits. These β subunits modulate channel expression and activity to increase functional diversity and render tissue specific phenotypes. This review focuses on the K(V) β subunits that contain transmembrane (TM) segments including the KCNE family and the β subunits of large conductance, Ca(2+)- and voltage-activated K(+) (BK) channels. These TM β subunits affect the voltage-dependent activation of K(V) α subunits. Experimental and computational studies have described the structural location of these β subunits in the channel complexes and the biophysical effects on VSD activation, PGD opening, and VSD-PGD coupling. These results reveal some common characteristics and mechanistic insights into K(V) channel modulation by TM β subunits.

  10. Thermodynamic coupling between activation and inactivation gating in potassium channels revealed by free energy molecular dynamics simulations

    Science.gov (United States)

    Pan, Albert C.; Cuello, Luis G.; Perozo, Eduardo

    2011-01-01

    The amount of ionic current flowing through K+ channels is determined by the interplay between two separate time-dependent processes: activation and inactivation gating. Activation is concerned with the stimulus-dependent opening of the main intracellular gate, whereas inactivation is a spontaneous conformational transition of the selectivity filter toward a nonconductive state occurring on a variety of timescales. A recent analysis of multiple x-ray structures of open and partially open KcsA channels revealed the mechanism by which movements of the inner activation gate, formed by the inner helices from the four subunits of the pore domain, bias the conformational changes at the selectivity filter toward a nonconductive inactivated state. This analysis highlighted the important role of Phe103, a residue located along the inner helix, near the hinge position associated with the opening of the intracellular gate. In the present study, we use free energy perturbation molecular dynamics simulations (FEP/MD) to quantitatively elucidate the thermodynamic basis for the coupling between the intracellular gate and the selectivity filter. The results of the FEP/MD calculations are in good agreement with experiments, and further analysis of the repulsive, van der Waals dispersive, and electrostatic free energy contributions reveals that the energetic basis underlying the absence of inactivation in the F103A mutation in KcsA is the absence of the unfavorable steric interaction occurring with the large Ile100 side chain in a neighboring subunit when the intracellular gate is open and the selectivity filter is in a conductive conformation. Macroscopic current analysis shows that the I100A mutant indeed relieves inactivation in KcsA, but to a lesser extent than the F103A mutant. PMID:22124115

  11. Voltage-gated Na+ Channel Activity Increases Colon Cancer Transcriptional Activity and Invasion Via Persistent MAPK Signaling

    Science.gov (United States)

    House, Carrie D.; Wang, Bi-Dar; Ceniccola, Kristin; Williams, Russell; Simaan, May; Olender, Jacqueline; Patel, Vyomesh; Baptista-Hon, Daniel T.; Annunziata, Christina M.; Silvio Gutkind, J.; Hales, Tim G.; Lee, Norman H.

    2015-06-01

    Functional expression of voltage-gated Na+ channels (VGSCs) has been demonstrated in multiple cancer cell types where channel activity induces invasive activity. The signaling mechanisms by which VGSCs promote oncogenesis remain poorly understood. We explored the signal transduction process critical to VGSC-mediated invasion on the basis of reports linking channel activity to gene expression changes in excitable cells. Coincidentally, many genes transcriptionally regulated by the SCN5A isoform in colon cancer have an over-representation of cis-acting sites for transcription factors phosphorylated by ERK1/2 MAPK. We hypothesized that VGSC activity promotes MAPK activation to induce transcriptional changes in invasion-related genes. Using pharmacological inhibitors/activators and siRNA-mediated gene knockdowns, we correlated channel activity with Rap1-dependent persistent MAPK activation in the SW620 human colon cancer cell line. We further demonstrated that VGSC activity induces downstream changes in invasion-related gene expression via a PKA/ERK/c-JUN/ELK-1/ETS-1 transcriptional pathway. This is the first study illustrating a molecular mechanism linking functional activity of VGSCs to transcriptional activation of invasion-related genes.

  12. Protein kinase CK2 is coassembled with small conductance Ca(2+)-activated K+ channels and regulates channel gating

    DEFF Research Database (Denmark)

    Bildl, Wolfgang; Strassmaier, Tim; Thurm, Henrike

    2004-01-01

    Small conductance Ca(2+)-activated K+ channels (SK channels) couple the membrane potential to fluctuations in intracellular Ca2+ concentration in many types of cells. SK channels are gated by Ca2+ ions via calmodulin that is constitutively bound to the intracellular C terminus of the channels and...

  13. Activation of thalamus in motor imagery results from gating by hypnosis.

    Science.gov (United States)

    Müller, Katharina; Bacht, Katrin; Prochnow, Denise; Schramm, Stefanie; Seitz, Rüdiger J

    2013-02-01

    The ability to mentally imagine the performance of automatic movements has been well-established being employed in sports and physiotherapy as a tool for motor learning and rehabilitation. This is probably mediated by engagement of the same brain areas as during real motor performance. Here we investigated the effect of hypnotic trance on the cerebral activation pattern engaged in motor imagery in 16 healthy, right-handed subjects using fMRI. Motor imagery as compared with rest was related to activations in the left medial frontal areas (preSMA/SMA), prefrontal- and frontal areas, putamen and inferior parietal areas. When compared with performance of the same movements motor imagery resulted in activation of the left middle frontal cortex, precuneus, and posterior cingulate. Under hypnotic trance there was one extra-activation in the left thalamus which occurred specifically in the motor imagery condition. The regional beta indices were highly correlated among the areas of the cortical-subcortical motor network. Our data accord with the notion that hypnotic trance enhances the motor control circuit engaged in motor imagery by modulating the gating function of the thalamus. Copyright © 2012 Elsevier Inc. All rights reserved.

  14. Dihydropyridine receptors actively control gating of ryanodine receptors in resting mouse skeletal muscle fibres

    Science.gov (United States)

    Robin, Gaëlle; Allard, Bruno

    2012-01-01

    Contraction of skeletal muscle is triggered by the release of Ca2+ from the sarcoplasmic reticulum (SR) in response to depolarization of the muscle membrane. Depolarization is known to elicit a conformational change of the dihydropyridine receptor (DHPR) in the tubular membrane that controls in a time- and voltage-dependent manner the opening of the ryanodine receptor (RyR), the SR Ca2+ release channel. At rest, it is assumed that RyRs are kept in a closed state imposed by the repressive action of DHPRs; however, a direct control of the RyR gating by the DHPR has up to now never been demonstrated in resting adult muscle. In this study, we monitored slow changes in SR Ca2+ content using the Ca2+ indicator fluo-5N loaded in the SR of voltage-clamped mouse muscle fibres. We first show that external Ca2+ removal induced a reversible SR Ca2+ efflux at −80 mV and prevented SR Ca2+ refilling following depolarization-evoked SR Ca2+ depletion. The dihydropyridine compound nifedipine induced similar effects. The rate of SR Ca2+ efflux was also shown to be controlled in a time- and voltage-dependent manner within a membrane potential range more negative than −50 mV. Finally, intracellular addition of ryanodine produced an irreversible SR Ca2+ efflux and kept the SR in a highly depleted state following depolarization-evoked SR Ca2+ depletion. The fact that resting SR Ca2+ efflux is modulated by conformational changes of DHPRs induced by external Ca2+, nifedipine and voltage demonstrates that DHPRs exert an active control on gating of RyRs in resting skeletal muscle. PMID:23006480

  15. The S4-S5 linker acts as a signal integrator for HERG K+ channel activation and deactivation gating.

    Science.gov (United States)

    Ng, Chai Ann; Perry, Matthew D; Tan, Peter S; Hill, Adam P; Kuchel, Philip W; Vandenberg, Jamie I

    2012-01-01

    Human ether-à-go-go-related gene (hERG) K(+) channels have unusual gating kinetics. Characterised by slow activation/deactivation but rapid inactivation/recovery from inactivation, the unique gating kinetics underlie the central role hERG channels play in cardiac repolarisation. The slow activation and deactivation kinetics are regulated in part by the S4-S5 linker, which couples movement of the voltage sensor domain to opening of the activation gate at the distal end of the inner helix of the pore domain. It has also been suggested that cytosolic domains may interact with the S4-S5 linker to regulate activation and deactivation kinetics. Here, we show that the solution structure of a peptide corresponding to the S4-S5 linker of hERG contains an amphipathic helix. The effects of mutations at the majority of residues in the S4-S5 linker of hERG were consistent with the previously identified role in coupling voltage sensor movement to the activation gate. However, mutations to Ser543, Tyr545, Gly546 and Ala548 had more complex phenotypes indicating that these residues are involved in additional interactions. We propose a model in which the S4-S5 linker, in addition to coupling VSD movement to the activation gate, also contributes to interactions that stabilise the closed state and a separate set of interactions that stabilise the open state. The S4-S5 linker therefore acts as a signal integrator and plays a crucial role in the slow deactivation kinetics of the channel.

  16. The effects of increased serotonergic activity on human sensory gating and its neural generators

    DEFF Research Database (Denmark)

    Frederiksen, Kristian Steen; Oranje, Bob; Wienberg, Malene

    2008-01-01

    RATIONALE: Schizophrenia is a disabling illness with deficits in core mental functions such as sensory gating. The P50 amplitude is an (usually auditory) evoked brain potential that, in a so-called double-click paradigm, can be used to quantify sensory gating. Reports on serotonergic modulation...

  17. Beyond a man's world: contributions from considering gender in the study of bus drivers' work activity.

    Science.gov (United States)

    Cunha, Liliana; Nogueira, Sónia; Lacomblez, Marianne

    2014-01-01

    Bus driving is a typically male occupation undergoing a process of feminization. Although men remain a majority, women's integration has raised some questions, namely, related to work organization or its impact on health. This paper focuses on the contributions of assuming a gender perspective in the analysis of the bus driving occupation and the conditions under which it is performed. Twenty female and 158 male bus drivers. Qualitative and quantitative approaches were combined. Ergonomic work analysis and individual interviews were used, as well as INSAT (Work and Health Questionnaire). Difficulties inherent to the work activity were highlighted, in terms of working hours and management of "peripheral tasks", with implications for the balance between professional and personal life. These difficulties were reported differently by men and women, although both made themselves clear about the impact on their career and health. Taking gender into consideration has enabled an enrichment of the questions that guide the analysis of this work activity, and contributed to a new perspective on the work performed by this occupational group as well as a new approach to study the history of the transport industry by proposing as focus of analysis issues related to "gender mobility".

  18. A trend analysis of global fire activity. Is it land use or climate the main driver?

    Science.gov (United States)

    Bistinas, Ioannis; Oom, Duarte; Silva, Joao M. N.; Lopez-Saldaña, Gerardo; Pereira, Jose M. C.

    2016-04-01

    We perform a global trend analysis of active fire counts at 0.5o spatial resolution, using 156 months (January 2001 - December 2013) of MODIS Climate Modelling Grid data (TERRA). We use the Contextual Mann-Kendall (CMK) test to assess the statistical significance at cell level and found that 13% of the global land area displays statistically significant active fire count trends, with a slight predominance of negative trends (50.63% of the total significant cells). We perform the same trend analysis with the unexplained variability (residuals) between active fires and the Fire Weather Index (FWI) that is used as a proxy for climate. There is agreement between the main patterns from the trend analysis coming from the residuals and the active fire trends, implying that the main contemporary fire trends are not climate driven. Spatially coherent patches with significant trends were found in all continents (with the obvious exception of Antarctica). The majority of significant trends occur in areas of high fire incidence, and both increasing and decreasing trends appear to be associated with land use change processes. The analysis reveals large negative trends at the Sahel and between Russia and Kazakhstan, whereas a massive and coherent positive trend appears in southeastern Asia. Smaller patches of positive trends appear in southeastern United States and in Mexico, as well as in Brazil and between Argentina and Paraguay, and in Asia in India. There are also negative trends in Brazil, Argentina and in Australia. The study highlights the land use activities as the main driver of these trends, but also the need for data driven analyses and longer time series for future studies in order to gain better knowledge on fire occurrence.

  19. Solar activity as driver for the Dark Age Grand Solar Minimum

    Science.gov (United States)

    Neuhäuser, Ralph; Neuhäuser, Dagmar

    2017-04-01

    surface temperature reconstructions. This indicates that solar activity is an important climate driver.

  20. Structural insights into Ca(2+)-activated long-range allosteric channel gating of RyR1.

    Science.gov (United States)

    Wei, Risheng; Wang, Xue; Zhang, Yan; Mukherjee, Saptarshi; Zhang, Lei; Chen, Qiang; Huang, Xinrui; Jing, Shan; Liu, Congcong; Li, Shuang; Wang, Guangyu; Xu, Yaofang; Zhu, Sujie; Williams, Alan J; Sun, Fei; Yin, Chang-Cheng

    2016-09-01

    Ryanodine receptors (RyRs) are a class of giant ion channels with molecular mass over 2.2 mega-Daltons. These channels mediate calcium signaling in a variety of cells. Since more than 80% of the RyR protein is folded into the cytoplasmic assembly and the remaining residues form the transmembrane domain, it has been hypothesized that the activation and regulation of RyR channels occur through an as yet uncharacterized long-range allosteric mechanism. Here we report the characterization of a Ca(2+)-activated open-state RyR1 structure by cryo-electron microscopy. The structure has an overall resolution of 4.9 Å and a resolution of 4.2 Å for the core region. In comparison with the previously determined apo/closed-state structure, we observed long-range allosteric gating of the channel upon Ca(2+) activation. In-depth structural analyses elucidated a novel channel-gating mechanism and a novel ion selectivity mechanism of RyR1. Our work not only provides structural insights into the molecular mechanisms of channel gating and regulation of RyRs, but also sheds light on structural basis for channel-gating and ion selectivity mechanisms for the six-transmembrane-helix cation channel family.

  1. Remote control of neuronal activity with a light-gated glutamate receptor.

    Science.gov (United States)

    Szobota, Stephanie; Gorostiza, Pau; Del Bene, Filippo; Wyart, Claire; Fortin, Doris L; Kolstad, Kathleen D; Tulyathan, Orapim; Volgraf, Matthew; Numano, Rika; Aaron, Holly L; Scott, Ethan K; Kramer, Richard H; Flannery, John; Baier, Herwig; Trauner, Dirk; Isacoff, Ehud Y

    2007-05-24

    The ability to stimulate select neurons in isolated tissue and in living animals is important for investigating their role in circuits and behavior. We show that the engineered light-gated ionotropic glutamate receptor (LiGluR), when introduced into neurons, enables remote control of their activity. Trains of action potentials are optimally evoked and extinguished by 380 nm and 500 nm light, respectively, while intermediate wavelengths provide graded control over the amplitude of depolarization. Light pulses of 1-5 ms in duration at approximately 380 nm trigger precisely timed action potentials and EPSP-like responses or can evoke sustained depolarizations that persist for minutes in the dark until extinguished by a short pulse of approximately 500 nm light. When introduced into sensory neurons in zebrafish larvae, activation of LiGluR reversibly blocks the escape response to touch. Our studies show that LiGluR provides robust control over neuronal activity, enabling the dissection and manipulation of neural circuitry in vivo.

  2. BARP suppresses voltage-gated calcium channel activity and Ca2+-evoked exocytosis.

    Science.gov (United States)

    Béguin, Pascal; Nagashima, Kazuaki; Mahalakshmi, Ramasubbu N; Vigot, Réjan; Matsunaga, Atsuko; Miki, Takafumi; Ng, Mei Yong; Ng, Yu Jin Alvin; Lim, Chiaw Hwee; Tay, Hock Soon; Hwang, Le-Ann; Firsov, Dmitri; Tang, Bor Luen; Inagaki, Nobuya; Mori, Yasuo; Seino, Susumu; Launey, Thomas; Hunziker, Walter

    2014-04-28

    Voltage-gated calcium channels (VGCCs) are key regulators of cell signaling and Ca(2+)-dependent release of neurotransmitters and hormones. Understanding the mechanisms that inactivate VGCCs to prevent intracellular Ca(2+) overload and govern their specific subcellular localization is of critical importance. We report the identification and functional characterization of VGCC β-anchoring and -regulatory protein (BARP), a previously uncharacterized integral membrane glycoprotein expressed in neuroendocrine cells and neurons. BARP interacts via two cytosolic domains (I and II) with all Cavβ subunit isoforms, affecting their subcellular localization and suppressing VGCC activity. Domain I interacts at the α1 interaction domain-binding pocket in Cavβ and interferes with the association between Cavβ and Cavα1. In the absence of domain I binding, BARP can form a ternary complex with Cavα1 and Cavβ via domain II. BARP does not affect cell surface expression of Cavα1 but inhibits Ca(2+) channel activity at the plasma membrane, resulting in the inhibition of Ca(2+)-evoked exocytosis. Thus, BARP can modulate the localization of Cavβ and its association with the Cavα1 subunit to negatively regulate VGCC activity.

  3. Active microorganisms as drivers of dynamic processes in soil: integration of basic teaching into research

    Science.gov (United States)

    Blagodatskaya, Evgenia; Kuzyakov, Yakov

    2013-04-01

    Traditionally lecture courses, seminars and even practical training are disconnected from real experimental studies and from ongoing research projects. As a result students passively participate in lectures and are helpless when they come to the laboratory to prepare their BSc or MSc theses. We introduce a training course, which is developed for Bachelor students to integrate the basic knowledge on soil microbiology and modern microbiological methods in ecological studies. The training course is focused on the importance of active microbial biomass as biogeochemical driver of soil processes. According to our concept soil functioning is closely related to and depends on the microbial activities, and only active microorganisms drive all processes. Despite this importance of active microorganisms, the most of methods are focused on the estimation of the total microbial biomass and fail to evaluate its activity. Our course demonstrates how the active physiological state of soil microorganisms can be related to the activity indicators such as respiration, molecular biomarkers and viable cell compartments (ATP, PLFA, RNA) determined in situ in soil. Each lecture begins with the set of provocative questions "What is wrong?" which help students to activate their knowledge from previous lectures. Information on on-going soil incubation experiments is integrated in the lectures as a special block. The students are required not only to learn the existing methods but to compare them and to evaluate critically the applicability of these methods to explain the results of on-going experiments. The seminars foreseen within training course are focused on critical discussions of the protocols and their adaptations to current experimental tasks. During practical part of training courses the students are associated in small research groups with a certain ecological tasks. Each group uses soil sub-samples from ongoing experiments and thus, the experimental data obtaining during the

  4. SNC-80-induced preconditioning: selective activation of the mitochondrial adenosine triphosphate-gated potassium channel.

    Science.gov (United States)

    Fischbach, Peter S; Barrett, Terrance D; Reed, Nathan J; Lucchesi, Benedict R

    2003-05-01

    Pharmacologic preconditioning by delta-opioid agonists occurs via activation of an adenosine triphosphate (ATP)-gated potassium channel (I(KATP)). Opening of mitochondrial I(KATP) confers pharmacologic preconditioning whereas opening the sarcolemmal I(KATP) shortens action potential duration and is proarrhythmic. This study investigated whether SNC-80, a selective delta-opioid agonist, is associated with development of ventricular arrhythmia due to activation of I(KATP). Rabbit isolated hearts were subjected to 12 min of hypoxia and 40 min of reoxygenation after pretreatment with SNC-80 (1 microM, n = 6), pinacidil (1.25 microM, n = 12), or BMS-191095 (6.0 microM, n = 4). Nine additional hearts served as controls. The cytoprotective effects of SNC-80 at a concentration of 1 microM were confirmed using 30 min of regional ischemia followed by 120 min of reperfusion. Ventricular fibrillation (VF) developed in 11 of 12 pinacidil-treated hearts whereas none of the SNC-80-treated (zero of six) hearts developed VF (P SNC-80 reduced infarct size expressed as a percentage of the area at risk from 33 +/- 4% to 14 +/- 3% (P = 0.004) compared with control. SNC-80, which selectively activates the delta-opioid receptor, provided cytoprotection but did not induce VF after hypoxia reoxygenation. The results indicate that pinacidil-induced nonselective activation of I(KATP) results in proarrhythmia that is dependent on activation of the sarcolemmal I(KATP). Selectivity for the mitochondrial I(KATP) is necessary to prevent induction of a proarrhythmic state.

  5. Identification of a protein–protein interaction between KCNE1 and the activation gate machinery of KCNQ1

    Science.gov (United States)

    Lvov, Anatoli; Gage, Steven D.; Berrios, Virla M.

    2010-01-01

    KCNQ1 channels assemble with KCNE1 transmembrane (TM) peptides to form voltage-gated K+ channel complexes with slow activation gate opening. The cytoplasmic C-terminal domain that abuts the KCNE1 TM segment has been implicated in regulating KCNQ1 gating, yet its interaction with KCNQ1 has not been described. Here, we identified a protein–protein interaction between the KCNE1 C-terminal domain and the KCNQ1 S6 activation gate and S4–S5 linker. Using cysteine cross-linking, we biochemically screened over 300 cysteine pairs in the KCNQ1–KCNE1 complex and identified three residues in KCNQ1 (H363C, P369C, and I257C) that formed disulfide bonds with cysteine residues in the KCNE1 C-terminal domain. Statistical analysis of cross-link efficiency showed that H363C preferentially reacted with KCNE1 residues H73C, S74C, and D76C, whereas P369C showed preference for only D76C. Electrophysiological investigation of the mutant K+ channel complexes revealed that the KCNQ1 residue, H363C, formed cross-links not only with KCNE1 subunits, but also with neighboring KCNQ1 subunits in the complex. Cross-link formation involving the H363C residue was state dependent, primarily occurring when the KCNQ1–KCNE1 complex was closed. Based on these biochemical and electrophysiological data, we generated a closed-state model of the KCNQ1–KCNE1 cytoplasmic region where these protein–protein interactions are poised to slow activation gate opening. PMID:20479109

  6. DRIVER INATTENTION

    Directory of Open Access Journals (Sweden)

    Richard TAY

    2004-01-01

    Full Text Available Driver inattention, especially driver distraction, is an extremely influential but generally neglected contributing factor of road crashes. This paper explores some of the common behaviours associated with several common forms of driver inattention, with respect to their perceived crash risks, rates of self-reported behaviours and whether drivers regulate such behaviours depending on the road and traffic environment, and provides some policy recommendations to address issues raised.

  7. Persistent discharges in dentate gyrus perisoma-inhibiting interneurons require hyperpolarization-activated cyclic nucleotide-gated channel activation.

    Science.gov (United States)

    Elgueta, Claudio; Köhler, Johannes; Bartos, Marlene

    2015-03-11

    Parvalbumin (PV)-expressing perisoma-inhibiting interneurons (PIIs) of the dentate gyrus integrate rapidly correlated synaptic inputs and generate short-duration action potentials that propagate along the axon to their output synapses, supporting fast inhibitory signaling onto their target cells. Here we show that PV-PIIs in rat and mouse dentate gyrus (DG) integrate their intrinsic activity over time and can turn into a persistent firing mode characterized by the ability to generate long-lasting trains of action potentials at ∼50 Hz in the absence of additional inputs. Persistent firing emerges in the axons remote from the axon initial segment and markedly depends on hyperpolarization-activated cyclic nucleotide-gated channel (HCNC) activation. Persistent firing properties are modulated by intracellular Ca(2+) levels and somatic membrane potential. Detailed computational single-cell PIIs models reveal that HCNC-mediated conductances can contribute to persistent firing during conditions of a shift in their voltage activation curve to more depolarized potentials. Paired recordings from PIIs and their target granule cells show that persistent firing supports strong inhibitory output signaling. Thus, persistent firing may emerge during conditions of intense activation of the network, thereby providing silencing to the circuitry and the maintenance of sparse activity in the dentate gyrus. Copyright © 2015 the authors 0270-6474/15/354131-09$15.00/0.

  8. Patterns and perceptions of physical activity and sedentary time in male transport drivers working in regional Australia.

    Science.gov (United States)

    Wong, Jason Y L; Gilson, Nicholas D; Bush, Robert A; Brown, Wendy J

    2014-08-01

    To objectively measure physical activity (PA) patterns and sedentary time, and explore perceptions of workplace PA opportunities in regional male transport workers. A multi-method study involving 28 drivers (52.4±9.69 years) working at a bus company in South-East Queensland, Australia. PA was measured using accelerometers (n=23) to determine the proportion of time spent in sedentary (work/non-work time (n=15). Interviews were conducted with 28 drivers and six managers to explore perceptions and ideas relating to workplace PA opportunities. Sedentary time was significantly higher on off-work (64% of wear time) than work (52%) days (pworking (44%) than when not working (60%; pwork and irregular driving routines), tended to preclude some drivers from engaging with these opportunities. Findings contest the notion that a sedentary occupation such as driving necessitates an inactive work environment. This research informs ongoing intervention efforts to target inactive drivers who are struggling to take advantage of existing workplace-related PA opportunities. © 2014 Public Health Association of Australia.

  9. A High-Performance Current-Mode Source Driver IC for Mobile Active Matrix Organic Light Emitting Diode Displays

    Science.gov (United States)

    Jeong, Il-Hun; Kwon, Oh-Kyong

    2008-03-01

    In this paper, we describe two types of 8-bit current-mode driver ICs with a small area and good performance for applications high accuracy current-mode digital-to-analog converters (DACs), and improved channel-to-channel uniformity for active matrix organic light-emitting diode (AMOLED) displays. One uses the proposed current steering DAC (type A), which is an improved architecture of a binary-weighted DAC, and the other uses a DAC that is a combination of a thermometer-decoded of the DAC and a binary-weighted type. The measured results show that the peak integral nonlinearity (INL) is within ±0.5 the least significant bit (LSB), the peak differential nonlinearity (DNL) is within ±0.5 LSB, and the nonuniformity of output current among channels and chips is within ±0.5 LSB. The size of the driver IC is 15,820 ×1,500 µm2 and the total power consumption of the current-mode driver IC is less than 9 mW when the display has full-white pattern with a luminance of 150 cd/m2. The chip area and power consumption with the proposed current DAC are reduced by 26 and 10%, respectively, compared with those of conventional driver ICs with a fully binary-weighted DAC.

  10. Intrinsic activity in the fly brain gates visual information during behavioral choices.

    Directory of Open Access Journals (Sweden)

    Shiming Tang

    Full Text Available The small insect brain is often described as an input/output system that executes reflex-like behaviors. It can also initiate neural activity and behaviors intrinsically, seen as spontaneous behaviors, different arousal states and sleep. However, less is known about how intrinsic activity in neural circuits affects sensory information processing in the insect brain and variability in behavior. Here, by simultaneously monitoring Drosophila's behavioral choices and brain activity in a flight simulator system, we identify intrinsic activity that is associated with the act of selecting between visual stimuli. We recorded neural output (multiunit action potentials and local field potentials in the left and right optic lobes of a tethered flying Drosophila, while its attempts to follow visual motion (yaw torque were measured by a torque meter. We show that when facing competing motion stimuli on its left and right, Drosophila typically generate large torque responses that flip from side to side. The delayed onset (0.1-1 s and spontaneous switch-like dynamics of these responses, and the fact that the flies sometimes oppose the stimuli by flying straight, make this behavior different from the classic steering reflexes. Drosophila, thus, seem to choose one stimulus at a time and attempt to rotate toward its direction. With this behavior, the neural output of the optic lobes alternates; being augmented on the side chosen for body rotation and suppressed on the opposite side, even though the visual input to the fly eyes stays the same. Thus, the flow of information from the fly eyes is gated intrinsically. Such modulation can be noise-induced or intentional; with one possibility being that the fly brain highlights chosen information while ignoring the irrelevant, similar to what we know to occur in higher animals.

  11. An electronically controlled automatic security access gate

    Directory of Open Access Journals (Sweden)

    Jonathan A. ENOKELA

    2014-11-01

    Full Text Available The security challenges being encountered in many places require electronic means of controlling access to communities, recreational centres, offices, and homes. The electronically controlled automated security access gate being proposed in this work helps to prevent an unwanted access to controlled environments. This is achieved mainly through the use of a Radio Frequency (RF transmitter-receiver pair. In the design a microcontroller is programmed to decode a given sequence of keys that is entered on a keypad and commands a transmitter module to send out this code as signal at a given radio frequency. Upon reception of this RF signal by the receiver module, another microcontroller activates a driver circuitry to operate the gate automatically. The codes for the microcontrollers were written in C language and were debugged and compiled using the KEIL Micro vision 4 integrated development environment. The resultant Hex files were programmed into the memories of the microcontrollers with the aid of a universal programmer. Software simulation was carried out using the Proteus Virtual System Modeling (VSM version 7.7. A scaled-down prototype of the system was built and tested. The electronically controlled automated security access gate can be useful in providing security for homes, organizations, and automobile terminals. The four-character password required to operate the gate gives the system an increased level of security. Due to its standalone nature of operation the system is cheaper to maintain in comparison with a manually operated type.

  12. Structure of a potentially open state of a proton-activated pentameric ligand-gated ion channel.

    Science.gov (United States)

    Hilf, Ricarda J C; Dutzler, Raimund

    2009-01-01

    The X-ray structure of a pentameric ligand-gated ion channel from Erwinia chrysanthemi (ELIC) has recently provided structural insight into this family of ion channels at high resolution. The structure shows a homo-pentameric protein with a barrel-stave architecture that defines an ion-conduction pore located on the fivefold axis of symmetry. In this structure, the wide aqueous vestibule that is encircled by the extracellular ligand-binding domains of the five subunits narrows to a discontinuous pore that spans the lipid bilayer. The pore is constricted by bulky hydrophobic residues towards the extracellular side, which probably serve as barriers that prevent the diffusion of ions. This interrupted pore architecture in ELIC thus depicts a non-conducting conformation of a pentameric ligand-gated ion channel, the thermodynamically stable state in the absence of bound ligand. As ligand binding promotes pore opening in these ion channels and the specific ligand for ELIC has not yet been identified, we have turned our attention towards a homologous protein from the cyanobacterium Gloebacter violaceus (GLIC). GLIC was shown to form proton-gated channels that are activated by a pH decrease on the extracellular side and that do not desensitize after activation. Both prokaryotic proteins, ELIC and GLIC form ion channels that are selective for cations over anions with poor discrimination among monovalent cations, characteristics that resemble the conduction properties of the cation-selective branch of the family that includes acetylcholine and serotonin receptors. Here we present the X-ray structure of GLIC at 3.1 A resolution. The structure reveals a conformation of the channel that is distinct from ELIC and that probably resembles the open state. In combination, both structures suggest a novel gating mechanism for pentameric ligand-gated ion channels where channel opening proceeds by a change in the tilt of the pore-forming helices.

  13. The impact of an m-Health financial incentives program on the physical activity and diet of Australian truck drivers.

    Science.gov (United States)

    Gilson, Nicholas D; Pavey, Toby G; Wright, Olivia Rl; Vandelanotte, Corneel; Duncan, Mitch J; Gomersall, Sjaan; Trost, Stewart G; Brown, Wendy J

    2017-05-18

    Chronic diseases are high in truck drivers and have been linked to work routines that promote inactivity and poor diets. This feasibility study examined the extent to which an m-Health financial incentives program facilitated physical activity and healthy dietary choices in Australian truck drivers. Nineteen men (mean [SD] age = 47.5 [9.8] years; BMI = 31.2 [4.6] kg/m(2)) completed the 20-week program, and used an activity tracker and smartphone application (Jawbone UP™) to regulate small positive changes in occupational physical activity, and fruit, vegetable, saturated fat and processed/refined sugar food/beverage choices. Measures (baseline, end-program, 2-months follow-up; April-December 2014) were accelerometer-determined proportions of work time spent physically active, and a workday dietary questionnaire. Statistical (repeated measures ANOVA) and thematic (interviews) analyses assessed program impact. Non-significant increases in the mean proportions of work time spent physically active were found at end-program and follow-up (+1%; 7 mins/day). Fruit (p = 0.023) and vegetable (p = 0.024) consumption significantly increased by one serve/day at end-program. Non-significant improvements in saturated fat (5%) and processed/refined sugar (1%) food/beverage choices were found at end-program and follow-up. Overall, 65% (n = 11) of drivers demonstrated positive changes in physical activity, and at least one dietary choice (e.g. saturated fat) at follow-up. Drivers found the financial incentives component of the program to be a less effective facilitator of change than the activity tracker and smartphone application, although this technology was easier to use for monitoring of physical activity than healthy dietary choices. Not all drivers benefitted from the program. However, positive changes for different health behaviours were observed in the majority of participants. Outcomes from this feasibility study inform future intervention development for

  14. Activity of the acyl-CoA synthetase ACSL6 isoforms: role of the fatty acid Gate-domains

    Directory of Open Access Journals (Sweden)

    Siliakus Melvin

    2010-04-01

    Full Text Available Abstract Background Activation of fatty acids by acyl-CoA synthetase enzymes is required for de novo lipid synthesis, fatty acid catabolism, and remodeling of biological membranes. Human long-chain acyl-CoA synthetase member 6, ASCL6, is a form present in the plasma membrane of cells. Splicing events affecting the amino-terminus and alternative motifs near the ATP-binding site generate different isoforms of ACSL6. Results Isoforms with different fatty acid Gate-domain motifs have different activity and the form lacking this domain, isoform 3, showed no detectable activity. Enzymes truncated of the first 40 residues generate acyl-CoAs at a faster rate than the full-length protein. The gating residue, which prevents entry of the fatty acid substrate unless one molecule of ATP has already accessed the catalytic site, was identified as a tyrosine for isoform 1 and a phenylalanine for isoform 2 at position 319. All isoforms, with or without a fatty acid Gate-domain, as well as recombinant protein truncated of the N-terminus, can interact to form enzymatic complexes with identical or different isoforms. Conclusion The alternative fatty acid Gate-domain motifs are essential determinants for the activity of the human ACSL6 isoforms, which appear to act as homodimeric enzyme as well as in complex with other spliced forms. These findings provide evidence that the diversity of these enzyme species could produce the variety of acyl-CoA synthetase activities that are necessary to generate and repair the hundreds of lipid species present in membranes.

  15. Walker mutations reveal loose relationship between catalytic and channel-gating activities of purified CFTR (cystic fibrosis transmembrane conductance regulator).

    Science.gov (United States)

    Ramjeesingh, M; Li, C; Garami, E; Huan, L J; Galley, K; Wang, Y; Bear, C E

    1999-02-02

    The cystic fibrosis transmembrane conductance regulator (CFTR) functions as an ATPase and as a chloride channel. It has been hypothesized, on the basis of electrophysiological findings, that the catalytic activity of CFTR is tightly coupled to the opening and closing of the channel gate. In the present study, to determine the structural basis for the ATPase activity of CFTR, we assessed the effect of mutations within the "Walker A" consensus motifs on ATP hydrolysis by the purified, intact protein. Mutation of the lysine residue in the "Walker A" motif of either the first nucleotide binding fold (CFTRK464A) or the second nucleotide binding fold (CFTRK1250A) inhibited the ATPase activity of the purified intact CFTR protein significantly, by greater than 50%. This finding suggests that the two nucleotide binding folds of CFTR are functioning cooperatively in catalysis. However, the rate of channel gating was only significantly inhibited in one of these purified mutants, CFTRK1250A, suggesting that ATPase activity may not be tightly coupled to channel gating as previously hypothesized.

  16. Actively phase-controlled coupling between plasmonic waveguides via in-between gain-assisted nanoresonator: nanoscale optical logic gates.

    Science.gov (United States)

    Ho, Kum-Song; Han, Yong-Ha; Ri, Chol-Song; Im, Song-Jin

    2016-08-15

    The development of nanoscale optical logic gates has attracted immense attention due to increasing demand for ultrahigh-speed and energy-efficient optical computing and data processing, however, suffers from the difficulty in precise control of phase difference of the two optical signals. We propose a novel conception of nanoscale optical logic gates based on actively phase-controlled coupling between two plasmonic waveguides via an in-between gain-assisted nanoresonator. Precise control of phase difference between the two plasmonic signals can be performed by manipulating pumping rate at an appropriate frequency detuning, enabling a high contrast between the output logic states "1" and "0." Without modification of the structural parameters, different logic functions can be provided. This active nanoscale optical logic device is expected to be quite energy-efficient with ideally low energy consumption on the order of 0.1 fJ/bit. Analytical calculations and numerical experiments demonstrate the validity of the proposed concept.

  17. Simulating the Activation of Voltage Sensing Domain for a Voltage-Gated Sodium Channel Using Polarizable Force Field.

    Science.gov (United States)

    Sun, Rui-Ning; Gong, Haipeng

    2017-03-02

    Voltage-gated sodium (NaV) channels play vital roles in the signal transduction of excitable cells. Upon activation of a NaV channel, the change of transmembrane voltage triggers conformational change of the voltage sensing domain, which then elicits opening of the pore domain and thus allows an influx of Na(+) ions. Description of this process with atomistic details is in urgent demand. In this work, we simulated the partial activation process of the voltage sensing domain of a prokaryotic NaV channel using a polarizable force field. We not only observed the conformational change of the voltage sensing domain from resting to preactive state, but also rigorously estimated the free energy profile along the identified reaction pathway. Comparison with the control simulation using an additive force field indicates that voltage-gating thermodynamics of NaV channels may be inaccurately described without considering the electrostatic polarization effect.

  18. Traffic flow impacts of adaptive cruise control deactivation and (Re)activation with cooperative driver behavior

    NARCIS (Netherlands)

    Klunder, G.; Li, M.; Minderhoud, M.

    2009-01-01

    In 2006 in the Netherlands, a field operational test was carried out to study the effect of adaptive cruise control (ACC) and lane departure warning on driver behavior and traffic flow in real traffic. To estimate the effect for larger penetration rates, simulations were needed. For a reliable

  19. Traffic flow impacts of adaptive cruise control deactivation and (Re)activation with cooperative driver behavior

    NARCIS (Netherlands)

    Klunder, G.; Li, M.; Minderhoud, M.

    2009-01-01

    In 2006 in the Netherlands, a field operational test was carried out to study the effect of adaptive cruise control (ACC) and lane departure warning on driver behavior and traffic flow in real traffic. To estimate the effect for larger penetration rates, simulations were needed. For a reliable impac

  20. 77 FR 74267 - Agency Information Collection Activities; New Information Collection Request: Driver and Carrier...

    Science.gov (United States)

    2012-12-13

    .... The survey will also collect information on the extent to which respondents believe that the use of... intermediaries. The proposed surveys for drivers and carriers collect information related to issues of EOBR... the collected information. Issued on: December 3, 2012. Kelly Leone, Associate Administrator...

  1. Cellular hyper-excitability caused by mutations that alter the activation process of voltage-gated sodium channels

    Directory of Open Access Journals (Sweden)

    Mohamed-Yassine eAMAROUCH

    2015-02-01

    Full Text Available Voltage-gated sodium channels (Nav are widely expressed as macro-molecular complexes in both excitable and non-excitable tissues. In excitable tissues, the upstroke of the action potential is the result of the passage of a large and rapid influx of sodium ions through these channels. NaV dysfunction has been associated with an increasingly wide range of neurological, muscular and cardiac disorders. The purpose of this review is to summarize the recently identified sodium channel mutations that are linked to hyper-excitability phenotypes and associated with the alteration of the activation process of voltage gated sodium channels. Indeed, several clinical manifestations that demonstrate an alteration of tissue excitability were recently shown to be strongly associated with the presence of mutations that affect the activation process of the voltage-gated sodium channels. These emerging genotype-phenotype correlations have expanded the clinical spectrum of sodium channelopathies to include disorders which feature a hyper-excitability phenotype that may or may not be associated with a cardiomyopathy. The p.I141V mutation in SCN4A and SCN5A, as well as its homologous p.I136V mutation in SCN9A, are interesting examples of mutations that have been linked to inherited hyperexcitability myotonia, exercise-induced polymorphic ventricular arrhythmias and erythromelalgia, respectively. Regardless of which sodium channel isoform is investigated, the substitution of the isoleucine to valine in the locus 141 induces similar modifications in the biophysical properties of the voltage-gated sodium channels by shifting the voltage-dependence of steady state activation towards more negative potentials.

  2. Trends in global vegetation activity and climatic drivers indicate a decoupled response to climate change

    DEFF Research Database (Denmark)

    Schut, Antonius G T; Ivits, Eva; Conijn, Jacob G.;

    2015-01-01

    Detailed understanding of a possible decoupling between climatic drivers of plant productivity and the response of ecosystems vegetation is required. We compared trends in six NDVI metrics (1982-2010) derived from the GIMMS3g dataset with modelled biomass productivity and assessed uncertainty...... an increasing difference between trends in climatic drivers and observed NDVI for large parts of the globe. Our findings suggest that future scenarios must consider impacts of constraints on plant growth such as extremes in weather and nutrient availability to predict changes in NPP and CO2 sequestration...... in trend estimates. Annual total biomass weight (TBW) was calculated with the LINPAC model. Trends were determined using a simple linear regression, a Thiel-Sen medium slope and a piecewise regression (PWR) with two segments. Values of NDVI metrics were related to Net Primary Production (MODIS...

  3. Modulation of voltage-gated sodium channels hyperpolarizes the voltage threshold for activation in spinal motoneurones.

    Science.gov (United States)

    Power, Kevin E; Carlin, Kevin P; Fedirchuk, Brent

    2012-03-01

    Previous work has shown that motoneurone excitability is enhanced by a hyperpolarization of the membrane potential at which an action potential is initiated (V(th)) at the onset, and throughout brainstem-evoked fictive locomotion in the adult decerebrate cat and neonatal rat. Modeling work has suggested the modulation of Na(+) conductance as a putative mechanism underlying this state-dependent change in excitability. This study sought to determine whether modulation of voltage-gated sodium channels could induce V(th) hyperpolarization. Whole-cell patch-clamp recordings were made from antidromically identified lumbar spinal motoneurones in an isolated neonatal rat spinal cord preparation. Recordings were made with and without the bath application of veratridine, a plant alkaloid neurotoxin that acts as a sodium channel modulator. As seen in HEK 293 cells expressing Nav1.2 channels, veratridine-modified channels demonstrated a hyperpolarizing shift in their voltage-dependence of activation and a slowing of inactivation that resulted in an enhanced inward current in response to voltage ramp stimulations. In the native rat motoneurones, veratridine-modified sodium channels induced a hyperpolarization of V(th) in all 29 neonatal rat motoneurones examined (mean hyperpolarization: -6.6 ± 4.3 mV). V(th) hyperpolarization was not due to the effects on Ca(2+) and/or K(+) channels as blockade of these currents did not alter V(th). Veratridine also significantly increased the amplitude of persistent inward currents (PICs; mean increase: 72.5 ± 98.5 pA) evoked in response to slow depolarizing current ramps. However, the enhancement of the PIC amplitude had a slower time course than the hyperpolarization of V(th), and the PIC onset voltage could be either depolarized or hyperpolarized, suggesting that PIC facilitation did not mediate the V(th) hyperpolarization. We therefore suggest that central neuronal circuitry in mammals could affect V(th) in a mechanism similar to that of

  4. Solution structure and alanine scan of a spider toxin that affects the activation of mammalian voltage-gated sodium channels.

    Science.gov (United States)

    Corzo, Gerardo; Sabo, Jennifer K; Bosmans, Frank; Billen, Bert; Villegas, Elba; Tytgat, Jan; Norton, Raymond S

    2007-02-16

    Magi 5, from the hexathelid spider Macrothele gigas, is a 29-residue polypeptide containing three disulfide bridges. It binds specifically to receptor site 4 on mammalian voltage-gated sodium channels and competes with scorpion beta-toxins, such as Css IV from Centruroides suffusus suffusus. As a consequence, Magi 5 shifts the activation voltage of the mammalian rNav1.2a channel to more hyperpolarized voltages, whereas the insect channel, DmNav1, is not affected. To gain insight into toxin-channel interactions, Magi 5 and 23 analogues were synthesized. The three-dimensional structure of Magi 5 in aqueous solution was determined, and its voltage-gated sodium channel-binding surfaces were mapped onto this structure using data from electrophysiological measurements on a series of Ala-substituted analogues. The structure clearly resembles the inhibitor cystine knot structural motif, although the triple-stranded beta-sheet typically found in that motif is partially distorted in Magi 5. The interactive surface of Magi 5 toward voltage-gated sodium channels resembles in some respects the Janus-faced atracotoxins, with functionally important charged residues on one face of the toxin and hydrophobic residues on the other. Magi 5 also resembles the scorpion beta-toxin Css IV, which has distinct nonpolar and charged surfaces that are critical for channel binding and has a key Glu involved in voltage sensor trapping. These two distinct classes of toxin, with different amino acid sequences and different structures, may utilize similar groups of residues on their surface to achieve the common end of modifying voltage-gated sodium channel function.

  5. Interactions between permeation and gating in the TMEM16B/anoctamin2 calcium-activated chloride channel.

    Science.gov (United States)

    Betto, Giulia; Cherian, O Lijo; Pifferi, Simone; Cenedese, Valentina; Boccaccio, Anna; Menini, Anna

    2014-06-01

    At least two members of the TMEM16/anoctamin family, TMEM16A (also known as anoctamin1) and TMEM16B (also known as anoctamin2), encode Ca(2+)-activated Cl(-) channels (CaCCs), which are found in various cell types and mediate numerous physiological functions. Here, we used whole-cell and excised inside-out patch-clamp to investigate the relationship between anion permeation and gating, two processes typically viewed as independent, in TMEM16B expressed in HEK 293T cells. The permeability ratio sequence determined by substituting Cl(-) with other anions (PX/PCl) was SCN(-) > I(-) > NO3 (-) > Br(-) > Cl(-) > F(-) > gluconate. When external Cl(-) was substituted with other anions, TMEM16B activation and deactivation kinetics at 0.5 µM Ca(2+) were modified according to the sequence of permeability ratios, with anions more permeant than Cl(-) slowing both activation and deactivation and anions less permeant than Cl(-) accelerating them. Moreover, replacement of external Cl(-) with gluconate, or sucrose, shifted the voltage dependence of steady-state activation (G-V relation) to more positive potentials, whereas substitution of extracellular or intracellular Cl(-) with SCN(-) shifted G-V to more negative potentials. Dose-response relationships for Ca(2+) in the presence of different extracellular anions indicated that the apparent affinity for Ca(2+) at +100 mV increased with increasing permeability ratio. The apparent affinity for Ca(2+) in the presence of intracellular SCN(-) also increased compared with that in Cl(-). Our results provide the first evidence that TMEM16B gating is modulated by permeant anions and provide the basis for future studies aimed at identifying the molecular determinants of TMEM16B ion selectivity and gating.

  6. 45% power saving in a 0.25μm BiCMOS 10Gb/s 50Ω-terminated packaged active-load laser driver

    DEFF Research Database (Denmark)

    Ayranci, E.; Christensen, K.; Andreani, Pietro

    2007-01-01

    A 0.25μm BiCMOS laser driver based on active loads allows operation at 10Gb/s while drawing 5mA from a 1.8V supply. The design guarantees the correct matching of the driver outputs without the use of physical 50Ω load resistors. This enables a theoretical current consumption reduction of 50% (45%...

  7. Cross-sectional surveillance study to phenotype lorry drivers' sedentary behaviours, physical activity and cardio-metabolic health

    National Research Council Canada - National Science Library

    Veronica Varela-Mato; Orlagh O'Shea; James A King; Thomas Yates; David J Stensel; Stuart JH Biddle; Myra A Nimmo; Stacy A Clemes

    2017-01-01

    ...) likely contribute to this elevated risk. This study behaviourally phenotyped UK lorry drivers' sedentary and non-sedentary behaviours during workdays and non-workdays and examined markers of drivers cardio-metabolic health...

  8. Interactions between permeation and gating in the TMEM16B/anoctamin2 calcium-activated chloride channel

    OpenAIRE

    Betto, Giulia; Cherian, O. Lijo; Pifferi, Simone; Cenedese, Valentina; Boccaccio, Anna; Menini, Anna

    2014-01-01

    At least two members of the TMEM16/anoctamin family, TMEM16A (also known as anoctamin1) and TMEM16B (also known as anoctamin2), encode Ca2+-activated Cl− channels (CaCCs), which are found in various cell types and mediate numerous physiological functions. Here, we used whole-cell and excised inside-out patch-clamp to investigate the relationship between anion permeation and gating, two processes typically viewed as independent, in TMEM16B expressed in HEK 293T cells. The permeability ratio se...

  9. Older Drivers

    Science.gov (United States)

    ... in this topic was provided by the National Highway Traffic Safety Administration Topic last reviewed: March 2015 For ... see Traffic Safety Facts 2012: Older Population. (National Highway Traffic Safety Administration). Crashes Down Among Older Drivers Fortunately, ...

  10. ERBB activation modulates sensitivity to MEK1/2 inhibition in a subset of driver-negative melanoma.

    Science.gov (United States)

    Hutchinson, Katherine E; Johnson, Douglas B; Johnson, Adam S; Sanchez, Violeta; Kuba, Maria; Lu, Pengcheng; Chen, Xi; Kelley, Mark C; Wang, Qingguo; Zhao, Zhongming; Kris, Mark; Berger, Michael F; Sosman, Jeffrey A; Pao, William

    2015-09-08

    Melanomas are characterized by activating "driver" mutations in BRAF, NRAS, KIT, GNAQ, and GNA11. Resultant mitogen-activated protein kinase (MAPK) pathway signaling makes some melanomas susceptible to BRAF (BRAF V600 mutations), MEK1/2 (BRAF V600, L597, fusions; NRAS mutations), or other kinase inhibitors (KIT), respectively. Among driver-negative ("pan-negative") patients, an unexplained heterogeneity of response to MEK1/2 inhibitors has been observed. Analysis of 16 pan-negative melanoma cell lines revealed that 8 (50%; termed Class I) are sensitive to the MEK1/2 inhibitor, trametinib, similar to BRAF V600E melanomas. A second set (termed Class II) display reduced trametinib sensitivity, paradoxical activation of MEK1/2 and basal activation of ERBBs 1, 2, and 3 (4 lines, 25%). In 3 of these lines, PI3K/AKT and MAPK pathway signaling is abrogated using the ERBB inhibitor, afatinib, and proliferation is even further reduced upon the addition of trametinib. A potential mechanism of ERBB activation in Class II melanomas is minimal expression of the ERK1/2 phosphatase, DUSP4, as ectopic restoration of DUSP4 attenuated ERBB signaling through potential modulation of the ERBB ligand, amphiregulin (AREG). Consistent with these data, immunohistochemical analysis of patient melanomas revealed a trend towards lower overall DUSP4 expression in pan-negative versus BRAF- and NRAS-mutant tumors. This study is the first to demonstrate that differential ERBB activity in pan-negative melanoma may modulate sensitivity to clinically-available MEK1/2 inhibitors and provides rationale for the use of ERBB inhibitors, potentially in combination with MEK1/2 inhibitors, in subsets of this disease.

  11. Trends in global vegetation activity and climatic drivers indicate a decoupled response to climate change

    DEFF Research Database (Denmark)

    Schut, Antonius G T; Ivits, Eva; Conijn, Jacob G.

    2015-01-01

    Detailed understanding of a possible decoupling between climatic drivers of plant productivity and the response of ecosystems vegetation is required. We compared trends in six NDVI metrics (1982-2010) derived from the GIMMS3g dataset with modelled biomass productivity and assessed uncertainty...... in trend estimates. Annual total biomass weight (TBW) was calculated with the LINPAC model. Trends were determined using a simple linear regression, a Thiel-Sen medium slope and a piecewise regression (PWR) with two segments. Values of NDVI metrics were related to Net Primary Production (MODIS......-NPP) and TBWper biome and land-use type. The simple linear and Thiel-Sen trends did not differ much whereas PWR increased the fraction of explained variation, depending on the NDVI metric considered. A positive trend in TBW indicating more favorable climatic conditions was found for 24% of pixels on land...

  12. Switch-mode High Voltage Drivers for Dielectric Electro Active Polymer (DEAP) Incremental Actuators

    DEFF Research Database (Denmark)

    Thummala, Prasanth

    , a new bidirectional flyback converter topology with multiple series connected outputs is proposed. A theoretical comparison showed that the proposed converter could improve the overall energy efficiency, lower the cost and reduce the volume of high voltage driver. Key words: high voltage, switch...... operation, and low power consumption. DEAP actuators require very high voltage (2-2.5 kV) to fully elongate them. In general, the elongation or stroke length of a DEAP actuator is of the order of mm. DEAP actuators can be configured to provide incremental motion, thus overcoming the inherent size......-to-stroke implications of conventional linear actuators, where the stroke is limited by their size. In incremental mode, DEAP actuators are several orders of magnitude shorter in their length compared to the stroke/elongation they provide. The dissertation presents design, control and implementation of switch-mode high...

  13. Trends in Global Vegetation Activity and Climatic Drivers Indicate a Decoupled Response to Climate Change.

    Directory of Open Access Journals (Sweden)

    Antonius G T Schut

    Full Text Available Detailed understanding of a possible decoupling between climatic drivers of plant productivity and the response of ecosystems vegetation is required. We compared trends in six NDVI metrics (1982-2010 derived from the GIMMS3g dataset with modelled biomass productivity and assessed uncertainty in trend estimates. Annual total biomass weight (TBW was calculated with the LINPAC model. Trends were determined using a simple linear regression, a Thiel-Sen medium slope and a piecewise regression (PWR with two segments. Values of NDVI metrics were related to Net Primary Production (MODIS-NPP and TBW per biome and land-use type. The simple linear and Thiel-Sen trends did not differ much whereas PWR increased the fraction of explained variation, depending on the NDVI metric considered. A positive trend in TBW indicating more favorable climatic conditions was found for 24% of pixels on land, and for 5% a negative trend. A decoupled trend, indicating positive TBW trends and monotonic negative or segmented and negative NDVI trends, was observed for 17-36% of all productive areas depending on the NDVI metric used. For only 1-2% of all pixels in productive areas, a diverging and greening trend was found despite a strong negative trend in TBW. The choice of NDVI metric used strongly affected outcomes on regional scales and differences in the fraction of explained variation in MODIS-NPP between biomes were large, and a combination of NDVI metrics is recommended for global studies. We have found an increasing difference between trends in climatic drivers and observed NDVI for large parts of the globe. Our findings suggest that future scenarios must consider impacts of constraints on plant growth such as extremes in weather and nutrient availability to predict changes in NPP and CO2 sequestration capacity.

  14. Pixel parallel localized driver design for a 128 x 256 pixel array 3D 1Gfps image sensor

    Science.gov (United States)

    Zhang, C.; Dao, V. T. S.; Etoh, T. G.; Charbon, E.

    2017-02-01

    In this paper, a 3D 1Gfps BSI image sensor is proposed, where 128 × 256 pixels are located in the top-tier chip and a 32 × 32 localized driver array in the bottom-tier chip. Pixels are designed with Multiple Collection Gates (MCG), which collects photons selectively with different collection gates being active at intervals of 1ns to achieve 1Gfps. For the drivers, a global PLL is designed, which consists of a ring oscillator with 6-stage current starved differential inverters, achieving a wide frequency tuning range from 40MHz to 360MHz (20ps rms jitter). The drivers are the replicas of the ring oscillator that operates within a PLL. Together with level shifters and XNOR gates, continuous 3.3V pulses are generated with desired pulse width, which is 1/12 of the PLL clock period. The driver array is activated by a START signal, which propagates through a highly balanced clock tree, to activate all the pixels at the same time with virtually negligible skew.

  15. hERG S4-S5 linker acts as a voltage-dependent ligand that binds to the activation gate and locks it in a closed state.

    Science.gov (United States)

    Malak, Olfat A; Es-Salah-Lamoureux, Zeineb; Loussouarn, Gildas

    2017-12-01

    Delayed-rectifier potassium channels (hERG and KCNQ1) play a major role in cardiac repolarization. These channels are formed by a tetrameric pore (S5-S6) surrounded by four voltage sensor domains (S1-S4). Coupling between voltage sensor domains and the pore activation gate is critical for channel voltage-dependence. However, molecular mechanisms remain elusive. Herein, we demonstrate that covalently binding, through a disulfide bridge, a peptide mimicking the S4-S5 linker (S4-S5L) to the channel S6 C-terminus (S6T) completely inhibits hERG. This shows that channel S4-S5L is sufficient to stabilize the pore activation gate in its closed state. Conversely, covalently binding a peptide mimicking S6T to the channel S4-S5L prevents its inhibiting effect and renders the channel almost completely voltage-independent. This shows that the channel S4-S5L is necessary to stabilize the activation gate in its closed state. Altogether, our results provide chemical evidence that S4-S5L acts as a voltage-controlled ligand that binds S6T to lock the channel in a closed state, elucidating the coupling between voltage sensors and the gate in delayed rectifier potassium channels and potentially other voltage-gated channels.

  16. Viewing marine bacteria, their activity and response to environmental drivers from orbit: satellite remote sensing of bacteria.

    Science.gov (United States)

    Grimes, D Jay; Ford, Tim E; Colwell, Rita R; Baker-Austin, Craig; Martinez-Urtaza, Jaime; Subramaniam, Ajit; Capone, Douglas G

    2014-04-01

    Satellite-based remote sensing of marine microorganisms has become a useful tool in predicting human health risks associated with these microscopic targets. Early applications were focused on harmful algal blooms, but more recently methods have been developed to interrogate the ocean for bacteria. As satellite-based sensors have become more sophisticated and our ability to interpret information derived from these sensors has advanced, we have progressed from merely making fascinating pictures from space to developing process models with predictive capability. Our understanding of the role of marine microorganisms in primary production and global elemental cycles has been vastly improved as has our ability to use the combination of remote sensing data and models to provide early warning systems for disease outbreaks. This manuscript will discuss current approaches to monitoring cyanobacteria and vibrios, their activity and response to environmental drivers, and will also suggest future directions.

  17. Impact of gate geometry on ionic liquid gated ionotronic systems

    Science.gov (United States)

    Wong, A. T.; Noh, J. H.; Pudasaini, P. R.; Wolf, B.; Balke, N.; Herklotz, A.; Sharma, Y.; Haglund, A. V.; Dai, S.; Mandrus, D.; Rack, P. D.; Ward, T. Z.

    2017-04-01

    Ionic liquid electrolytes are gaining widespread application as a gate dielectric used to control ion transport in functional materials. This letter systematically examines the important influence that device geometry in standard "side gate" 3-terminal geometries plays in device performance of a well-known oxygen ion conductor. We show that the most influential component of device design is the ratio between the area of the gate electrode and the active channel, while the spacing between these components and their individual shapes has a negligible contribution. These findings provide much needed guidance in device design intended for ionotronic gating with ionic liquids.

  18. Counter-driver shock tube

    Science.gov (United States)

    Tamba, T.; Nguyen, T. M.; Takeya, K.; Harasaki, T.; Iwakawa, A.; Sasoh, A.

    2015-11-01

    A "counter-driver" shock tube was developed. In this device, two counter drivers are actuated with an appropriate delay time to generate the interaction between a shock wave and a flow in the opposite direction which is induced by another shock wave. The conditions for the counter drivers can be set independently. Each driver is activated by a separate electrically controlled diaphragm rupture device, in which a pneumatic piston drives a rupture needle with a temporal jitter of better than 1.1 ms. Operation demonstrations were conducted to evaluate the practical performance.

  19. Effect of gating currents of ion channels on the collective spiking activity of coupled Hodgkin-Huxley neurons

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Based on the coupled stochastic Hodgkin-Huxley neurons, we numerically studied the effect of gating currents of ion channels, as well as coupling and the number of neurons, on the collective spiking rate and regularity in the coupled system. It was found, for a given coupling strength and with a relatively large number of neurons, when gating currents are applied, the collective spiking regularity decreases; meanwhile, the collective spiking rate increases, indicating that gating currents can aggravate the de-synchronization of the spikings of all neurons. However, gating currents caused hardly any effect in the spiking of any individual neuron of the coupled system. This result, different from the reduction of the spiking rate by gating currents in a single neuron, provides a new insight into the effect of gating cur-rents on the global information processing and signal transduction in real neural systems.

  20. Effect of gating currents of ion channels on the collective spiking activity of coupled Hodξkin-Huxley neurons

    Institute of Scientific and Technical Information of China (English)

    GONG YuBing; XIE YanHang; XU Bo; MA XiaoGuang

    2009-01-01

    Based on the coupled stochastic Hodgkin-Huxley neurons, we numerically studied the effect of gating currents of ion channels, as well as coupling and the number of neurons, on the collective spiking rate and regularity in the coupled system, it was found, for a given coupling strength and with a relatively large number of neurons, when gating currents are applied, the collective spiking regularity decreases; meanwhile, the collective spiking rate increases, indicating that gating currents can aggravate the de-synchronization of the spikings of all neurons. However, gating currents caused hardly any effect in the spiking of any individual neuron of the coupled system. This result, different from the reduction of the spiking rate by gating currents in a single neuron, provides a new insight into the effect of gating cur-rents on the global information processing and signal transduction in real neural systems.

  1. Gaussian mixture models and semantic gating improve reconstructions from human brain activity

    Directory of Open Access Journals (Sweden)

    Sanne eSchoenmakers

    2015-01-01

    Full Text Available Better acquisition protocols and analysis techniques are making it possible to use fMRI to obtain highly detailed visualizations of brain processes. In particular we focus on the reconstruction of natural images from BOLD responses in visual cortex. We expand our linear Gaussian framework for percept decoding with Gaussian mixture models to better represent the prior distribution of natural images. Reconstruction of such images then boils down to probabilistic inference in a hybrid Bayesian network. In our set-up, different mixture components correspond to different character categories. Our framework can automatically infer higher-order semantic categories from lower-level brain areas. Furthermore the framework can gate semantic information from higher-order brain areas to enforce the correct category during reconstruction. When categorical information is not available, we show that automatically learned clusters in the data give a similar improvement in reconstruction. The hybrid Bayesian network leads to highly accurate reconstructions in both supervised and unsupervised settings.

  2. Phenolic acids isolated from the fungus Schizophyllum commune exert analgesic activity by inhibiting voltage-gated sodium channels.

    Science.gov (United States)

    Yao, Hui-Min; Wang, Gan; Liu, Ya-Ping; Rong, Ming-Qiang; Shen, Chuan-Bin; Yan, Xiu-Wen; Luo, Xiao-Dong; Lai, Ren

    2016-09-01

    The present study was designed to search for compounds with analgesic activity from the Schizophyllum commune (SC), which is widely consumed as edible and medicinal mushroom world. Thin layer chromatography (TLC), tosilica gel column chromatography, sephadex LH 20, and reverse-phase high performance liquid chromatography (RP-HPLC) were used to isolate and purify compounds from SC. Structural analysis of the isolated compounds was based on nuclear magnetic resonance (NMR). The effects of these compounds on voltage-gated sodium (NaV) channels were evaluated using patch clamp. The analgesic activity of these compounds was tested in two types of mouse pain models induced by noxious chemicals. Five phenolic acids identified from SC extracts in the present study included vanillic acid, m-hydroxybenzoic acid, o-hydroxybenzeneacetic acid, 3-hydroxy-5-methybenzoic acid, and p-hydroxybenzoic acid. They inhibited the activity of both tetrodotoxin-resistant (TTX-r) and tetrodotoxin-sensitive (TTX-s) NaV channels. All the compounds showed low selectivity on NaV channel subtypes. After intraperitoneal injection, three compounds of these compounds exerted analgesic activity in mice. In conclusion, phenolic acids identified in SC demonstrated analgesic activity, facilitating the mechanistic studies of SC in the treatment of neurasthenia.

  3. Synergistic activation of G protein-gated inwardly rectifying potassium channels by cholesterol and PI(4,5)P2.

    Science.gov (United States)

    Bukiya, Anna N; Rosenhouse-Dantsker, Avia

    2017-07-01

    G-protein gated inwardly rectifying potassium (GIRK or Kir3) channels play a major role in the control of the heart rate, and require the membrane phospholipid phosphatidylinositol-bis-phosphate (PI(4,5)P2) for activation. Recently, we have shown that the activity of the heterotetrameric Kir3.1/Kir3.4 channel that underlies atrial KACh currents was enhanced by cholesterol. Similarly, the activities of both the Kir3.4 homomer and its active pore mutant Kir3.4* (Kir3.4_S143T) were also enhanced by cholesterol. Here we employ planar lipid bilayers to investigate the crosstalk between PI(4,5)P2 and cholesterol, and demonstrate that these two lipids act synergistically to activate Kir3.4* currents. Further studies using the Xenopus oocytes heterologous expression system suggest that PI(4,5)P2 and cholesterol act via distinct binding sites. Whereas PI(4,5)P2 binds to the cytosolic domain of the channel, the putative binding region of cholesterol is located at the center of the transmembrane domain overlapping the central glycine hinge region of the channel. Together, our data suggest that changes in the levels of two key membrane lipids - cholesterol and PI(4,5)P2 - could act in concert to provide fine-tuning of Kir3 channel function. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Sympathoadrenal activation and endotheliopathy are drivers of hypocoagulability and hyperfibrinolysis in trauma

    DEFF Research Database (Denmark)

    Ostrowski, Sisse R; Henriksen, Hanne Herborg; Stensballe, Jakob

    2017-01-01

    BACKGROUND: One third of severely injured patients present with a laboratory-based diagnosis of coagulopathy. This study investigated clinical and biomarker profile of patients with rapid thrombelastography (rTEG) coagulopathy, hypothesizing that sympathoadrenal activation and endothelial damage ...

  5. Spatial and temporal patterns of rockfall activity - Drivers, precursors, kinetics and evolution

    Science.gov (United States)

    Dietze, Michael; Turowski, Jens; Hovius, Niels

    2017-04-01

    Rockfalls are key processes in steep alpine landscapes but hard to monitor by classic techniques under natural conditions due to their unpredictable and rapid evolution. In contrast, seismic methods allow rockfall event detection, localisation and tracking, describtion of the temporal evolution, of the precursor activity and of external triggers. To exploit these capabilities, a 700 m high, nearly vertical limestone cliff section in the Lauterbrunnen Valley, Bernese Oberland, Switzerland, was instrumented with six broadband seismometers for more than six months during two distinct campaigns: late summer/autumn 2014 and spring 2015. A total of 49 rockfalls events (17 in 2014 and 32 in 2015) were detected that occurred in the monitored cliff section. There were distinct spatial and temporal activity patterns at different observational scales: in summer/autumn rockfalls detached near the cliff base of the southern part, whereas in spring material was released at the upper and middle cliff parts from three activity hotspots - a downward annual vertical activity shift of 40-50 m/month. Rockfalls can be classified into three evolutionary types ("single impact", "multiple impact" and "avalanche-like") and showed seismic signals indicating precursor activity (e.g., crack propagation). Lag times for potential trigger mechanisms of 2-3 hours on average reveal that there is a tight temporal correlation of rockfall activity to rainfall and freeze-thaw transitions. Throughout the day, there are four distinct activity phases related to absolute temperature, temperature change rate and precipitation intensity. The contribution highlights the potential of environmental seismology to give profound and holistic insight into rockfall activity in a prototype landscape, representative for many other alpine catchments.

  6. Interactive drivers of activity in a free-ranging estuarine predator.

    Directory of Open Access Journals (Sweden)

    Matthew D Taylor

    Full Text Available Animal activity patterns evolve as an optimal balance between energy use, energy acquisition, and predation risk, so understanding how animals partition activity relative to extrinsic environmental fluctuations is central to understanding their ecology, biology and physiology. Here we use accelerometry to examine the degree to which activity patterns of an estuarine teleost predator are driven by a series of rhythmic and arrhythmic environmental fluctuations. We implanted free-ranging bream Acanthopagrus australis with acoustic transmitters that measured bi-axial acceleration and pressure (depth, and simultaneously monitored a series of environmental variables (photosynthetically active radiation, tidal height, temperature, turbidity, and lunar phase for a period of approximately four months. Linear modeling showed an interaction between fish activity, light level and tidal height; with activity rates also negatively correlated with fish depth. These patterns highlight the relatively-complex trade-offs that are required to persist in highly variable environments. This study demonstrates how novel acoustic sensor tags can reveal interactive links between environmental cycles and animal behavior.

  7. Fluorescence-tracking of activation gating in human ERG channels reveals rapid S4 movement and slow pore opening.

    Directory of Open Access Journals (Sweden)

    Zeineb Es-Salah-Lamoureux

    Full Text Available BACKGROUND: hERG channels are physiologically important ion channels which mediate cardiac repolarization as a result of their unusual gating properties. These are very slow activation compared with other mammalian voltage-gated potassium channels, and extremely rapid inactivation. The mechanism of slow activation is not well understood and is investigated here using fluorescence as a direct measure of S4 movement and pore opening. METHODS AND FINDINGS: Tetramethylrhodamine-5-maleimide (TMRM fluorescence at E519 has been used to track S4 voltage sensor movement, and channel opening and closing in hERG channels. Endogenous cysteines (C445 and C449 in the S1-S2 linker bound TMRM, which caused a 10 mV hyperpolarization of the V((1/2 of activation to -27.5+/-2.0 mV, and showed voltage-dependent fluorescence signals. Substitution of S1-S2 linker cysteines with valines allowed unobstructed recording of S3-S4 linker E519C and L520C emission signals. Depolarization of E519C channels caused rapid initial fluorescence quenching, fit with a double Boltzmann relationship, F-V(ON, with V((1/2 (,1 = -37.8+/-1.7 mV, and V((1/2 (,2 = 43.5+/-7.9 mV. The first phase, V((1/2 (,1, was approximately 20 mV negative to the conductance-voltage relationship measured from ionic tail currents (G-V((1/2 = -18.3+/-1.2 mV, and relatively unchanged in a non-inactivating E519C:S620T mutant (V((1/2 = -34.4+/-1.5 mV, suggesting the fast initial fluorescence quenching tracked S4 voltage sensor movement. The second phase of rapid quenching was absent in the S620T mutant. The E519C fluorescence upon repolarization (V((1/2 = -20.6+/-1.2, k = 11.4 mV and L520C quenching during depolarization (V((1/2 = -26.8+/-1.0, k = 13.3 mV matched the respective voltage dependencies of hERG ionic tails, and deactivation time constants from -40 to -110 mV, suggesting they detected pore-S4 rearrangements related to ionic current flow during pore opening and closing. CONCLUSION: THE DATA INDICATE: 1

  8. Exciting New Take on a Classic: Crash Testing Activity Puts the Egg in the Driver's Seat

    Science.gov (United States)

    Board, Keith

    2011-01-01

    An excellent common activity in technology and engineering classes involves dropping an egg from a significant height in a protective device designed and built by students. This article describes how the author uses the classic "egg drop" as an inspiration to have students modify a small crash test vehicle that speeds down a track and crashes into…

  9. Exciting New Take on a Classic: Crash Test Activity Puts the Egg in the Driver's Seat

    Science.gov (United States)

    Board, Keith

    2011-01-01

    An excellent common activity in technology and engineering classes involves dropping an egg from a significant height in a protective device designed and built by students. This article describes how the author uses the classic "egg drop" as an inspiration to have students modify a small crash test vehicle that speeds down a track and crashes into…

  10. Drivers of Engagement in Professional Development Activity: A Study of Undergraduate Business Majors

    Science.gov (United States)

    Snell, Corinne M.

    2012-01-01

    Since college and university students typically vary in their utilization of student services and resources, the variance in undergraduate business student engagement levels in professional development activity was explored by this quantitative study. Professional development is defined as career-related preparation of students for entry into the…

  11. Importance of post-shock streams and sheath region as drivers of intense magnetospheric storms and high-latitude activity

    Directory of Open Access Journals (Sweden)

    K. E. J. Huttunen

    2004-04-01

    Full Text Available Magnetic disturbances in the Earth's magnetosphere can be very different depending on the type of solar wind driver. We have determined the solar wind causes for intense magnetic storms (Dst<-100nT over a 6-year period from the beginning of 1997 to the end of 2002, using observations by the WIND and ACE spacecraft. We have taken into consideration whether the storm was caused by the sheath region or by the following interplanetary coronal mass ejection (ICME. We also divided ICMEs into those having a magnetic cloud structure and those without such a structure. We found that post-shock streams and sheath regions caused the largest fraction of intense magnetic storms. We present four periods of magnetospheric activity in more detail. One of the events was caused by a magnetic cloud (10-11 August 2000 and the rest (13-14 July 2000, 8-9 June 2000 and 17-18 April 2001 by sheath regions and post-shock streams. We have used several magnetic indices to monitor the low- and high-latitude magnetospheric response to these different solar wind structures. Two of the events are interesting examples where at first strong high-latitude activity took place and the low-latitude response followed several hours later. These events demonstrate that low- and high-latitude activity do not always occur concurrently and the level of activity may be very different. According to the examples shown the evolution of the pressure-corrected Dst index was more difficult to model for a sheath region or a post-shock stream driven storm than for a storm caused by a magnetic cloud.

  12. CREB activity in the nucleus accumbens shell controls gating of behavioral responses to emotional stimuli

    NARCIS (Netherlands)

    Barrot, Michel; Olivier, Jocelien D A; Perrotti, Linda I; DiLeone, Ralph J; Berton, Olivier; Eisch, Amelia J; Impey, Soren; Storm, Daniel R; Neve, Rachael L; Yin, Jerry C; Zachariou, Venetia; Nestler, Eric J

    2002-01-01

    The transcription factor cAMP response element (CRE)-binding protein (CREB) has been shown to regulate neural plasticity. Drugs of abuse activate CREB in the nucleus accumbens, an important part of the brain's reward pathways, and local manipulations of CREB activity have been shown to affect cocain

  13. Drivers of Concentration of Economic Activity in Russia’s Regions

    Directory of Open Access Journals (Sweden)

    Svetlana Nikolaevna Rastvortseva

    2016-05-01

    Full Text Available The uneven distribution of economic activity in Russia promotes the differentiation of its constituent entities by level of development. Regions are independent participants of economic relations, and they often act as competitors rather than partners. Agglomeration effects arise in more successful regions and contribute to the concentration of resources, manufacturing enterprises, service providers, skilled workers, and scientific and technological knowledge. The aim of the study, the results of which are reflected in the paper, is to identify the factors and assess their impact on the concentration (dispersion of economic activity on the basis of Russia’s regions. The paper describes the benefits of agglomeration processes from the standpoint of economic geography, allocation theory and international trade theory. The concentration of economic activity in Russia’s regions is estimated by the Herfindahl–Hirschman index of industrial production taking into consideration the volume of investments in fixed capital and the number of people employed in the economy in Russia’s regions in 1990–2013. It is determined that fixed capital investments have the propensity to concentrate, but react strongly to economic crises. Labor resources, by contrast, are distributed relatively evenly, and their concentration in certain regions is increasing steadily. The article considers key factors such as wage growth, distance to large cities, direct foreign investment, road network density, the degree of development of the services sector in the region. The factor model is constructed using the least squares method. The authors conclude that the growth of wages in the region (relative to national average has a negative effect on the concentration of economic activity. There is a positive correlation between the growth of direct foreign investment and the density of hard surface roads. The development of services has the greatest positive impact on

  14. Hyperpolarization-activated cyclic nucleotide-gated cation channel subtypes differentially modulate the excitability of murine small intestinal afferents

    Institute of Scientific and Technical Information of China (English)

    Ying-Ping Wang; Bi-Ying Sun; Qian Li; Li Dong; Guo-Hua Zhang; David Grundy; Wei-Fang Rong

    2012-01-01

    AIM: To assess the role of hyperpolarization-activated cyclic nucleotide-gated cation (HCN) channels in regulating the excitability of vagal and spinal gut afferents.METHODS: The mechanosensory response of mesen-teric afferent activity was measured in an ex vivo murine jejunum preparation. HCN channel activity was recorded through voltage and current clamp in acutely dissociated dorsal root ganglia (DRG) and nodose ganglia (NG) neurons retrogradely labeled from the small intestine through injection of a fluorescent marker (DiI). The isoforms of HCN channels expressed in DRG and NG neurons were examined by immunohistochemistry.RESULTS: Ramp distension of the small intestine evoked biphasic increases in the afferent nerve activity, reflecting the activation of low- and high-threshold fibers.HCN blocker CsCl (5 mmol/L) preferentially inhibited the responses of low-threshold fibers to distension and showed no significant effects on the high-threshold responses. The effect of CsCl was mimicked by the more selective HCN blocker ZD7288 (10 ?mol/L). In 71.4% of DiI labeled DRG neurons (n = 20) and 90.9% of DiI labeled NG neurons (n = 10), an inward current (Ih current) was evoked by hyperpolarization pulses which was fully eliminated by extracellular CsCl. In neurons expressing Ih current, a typical "sag" was observed upon injection of hyperpolarizing current pulses in current-clamp recordings. CsCl abolished the sag entirely. In some DiI labeled DRG neurons, the Ih current was potentiated by 8-Br-cAMP, which had no effect on the Ih current of DiI labeled NG neurons. Immunohistochemistry revealed differential expression of HCN isoforms in vagal and spinal afferents, and HCN2 and HCN3 seemed to be the dominant isoform in DRG and NG, respectively.CONCLUSION: HCNs differentially regulate the excitability of vagal and spinal afferent of murine small intestine.

  15. Geochemical drivers of organic matter decomposition in the active layer of Arctic tundra

    Science.gov (United States)

    Herndon, E.; Roy Chowdhury, T.; Mann, B.; Graham, D. E.; Wullschleger, S. D.; Gu, B.; Liang, L.

    2014-12-01

    Arctic tundra soils store large quantities of organic carbon that are susceptible to decomposition and release to the atmosphere as CO2 and CH4. Decomposition rates are limited by cold temperatures and widespread anoxia; however, ongoing changes in soil temperature, thaw depth, and water saturation are expected to influence rates and pathways of organic matter decomposition. In order to predict greenhouse gas releases from high-latitude ecosystems, it is necessary to identify how geochemical factors (e.g. terminal electron acceptors, carbon substrates) influence CO2 and CH4 production in tundra soils. This study evaluates spatial patterns of aqueous geochemistry in the active layer of low- to high-centered polygons located at the Barrow Environmental Observatory in northern Alaska. Pore waters from saturated soils were low in sulfate and nitrate but contained abundant Fe which may serve a major terminal electron acceptor for anaerobic microbial metabolism. Relatively high concentrations of soluble Fe accumulated in the middle of the active layer near the boundary between the organic and mineral horizon, and we infer that Fe-oxide reduction and dissolution in the mineral horizon produced soluble Fe that diffused upwards and was stabilized by complexation with dissolved organic matter. Fe concentrations in the bulk soil were higher in organic than mineral horizons due to the presence of these organic-Fe complexes and Fe-oxide precipitates. Dissolved CH4 increased with increasing proportions of dissolved Fe(III) in saturated soils from transitional and low-centered polygons. The opposite trend was observed in drier soils from flat- and high-centered polygons where deeper oxidation fronts may inhibit methanogenesis. Using multiple spectroscopic and molecular methods (e.g. UV-Vis, Fourier transform infrared, ultrahigh resolution mass spectrometry), we also observed that pore waters from the middle of the active layer contained more aromatic organics than in mineral

  16. Cholesterol up-regulates neuronal G protein-gated inwardly rectifying potassium (GIRK) channel activity in the hippocampus.

    Science.gov (United States)

    Bukiya, Anna N; Durdagi, Serdar; Noskov, Sergei; Rosenhouse-Dantsker, Avia

    2017-04-14

    Hypercholesterolemia is a well known risk factor for the development of neurodegenerative disease. However, the underlying mechanisms are mostly unknown. In recent years, it has become increasingly evident that cholesterol-driven effects on physiology and pathophysiology derive from its ability to alter the function of a variety of membrane proteins including ion channels. Yet, the effect of cholesterol on G protein-gated inwardly rectifying potassium (GIRK) channels expressed in the brain is unknown. GIRK channels mediate the actions of inhibitory brain neurotransmitters. As a result, loss of GIRK function can enhance neuron excitability, whereas gain of GIRK function can reduce neuronal activity. Here we show that in rats on a high-cholesterol diet, cholesterol levels in hippocampal neurons are increased. We also demonstrate that cholesterol plays a critical role in modulating neuronal GIRK currents. Specifically, cholesterol enrichment of rat hippocampal neurons resulted in enhanced channel activity. In accordance, elevated currents upon cholesterol enrichment were also observed in Xenopus oocytes expressing GIRK2 channels, the primary GIRK subunit expressed in the brain. Furthermore, using planar lipid bilayers, we show that although cholesterol did not affect the unitary conductance of GIRK2, it significantly enhanced the frequency of channel openings. Last, combining computational and functional approaches, we identified two putative cholesterol-binding sites in the transmembrane domain of GIRK2. These findings establish that cholesterol plays a critical role in modulating GIRK activity in the brain. Because up-regulation of GIRK function can reduce neuronal activity, our findings may lead to novel approaches for prevention and therapy of cholesterol-driven neurodegenerative disease. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. Cooperative gating between ion channels.

    Science.gov (United States)

    Choi, Kee-Hyun

    2014-01-01

    Cooperative gating between ion channels, i.e. the gating of one channel directly coupled to the gating of neighboring channels, has been observed in diverse channel types at the single-channel level. Positively coupled gating could enhance channel-mediated signaling while negative coupling may effectively reduce channel gating noise. Indeed, the physiological significance of cooperative channel gating in signal transduction has been recognized in several in vivo studies. Moreover, coupled gating of ion channels was reported to be associated with some human disease states. In this review, physiological roles for channel cooperativity and channel clustering observed in vitro and in vivo are introduced, and stimulation-induced channel clustering and direct channel cross linking are suggested as the physical mechanisms of channel assembly. Along with physical clustering, several molecular mechanisms proposed as the molecular basis for functional coupling of neighboring channels are covered: permeant ions as a channel coupling mediator, concerted channel activation through the membrane, and allosteric mechanisms. Also, single-channel analysis methods for cooperative gating such as the binomial analysis, the variance analysis, the conditional dwell time density analysis, and the maximum likelihood fitting analysis are reviewed and discussed.

  18. Sunspot Rotation as a Driver of Major Solar Eruptions in NOAA Active Region 12158

    CERN Document Server

    Vemareddy, P; Ravindra, B

    2016-01-01

    We studied the developing conditions of sigmoid structure under the influence of magnetic non-potential characteristics of a rotating sunspot in the active region (AR) 12158. Vector magnetic field measurements from Helioseismic Magnetic Imager and coronal EUV observations from Atmospheric Imaging Assembly reveal that the erupting inverse-S sigmoid had roots in the location of the rotating sunspot. Sunspot rotates at a rate of 0-5deg/h with increasing trend in the first half followed by a decrease. Time evolution of many non-potential parameters had a well correspondence with the sunspot rotation. The evolution of the AR magnetic structure is approximated by a time series of force free equilibria. The NLFFF magnetic structure around the sunspot manifests the observed sigmoid structure. Field lines from the sunspot periphery constitute the body of the sigmoid and those from interior overly the sigmoid similar to a fluxrope structure. While the sunspot is being rotating, two major CME eruptions occurred in the A...

  19. A temporal gate for viral enhancers to co-opt Toll-like-receptor transcriptional activation pathways upon acute infection.

    Science.gov (United States)

    Kropp, Kai A; Hsieh, Wei Yuan; Isern, Elena; Forster, Thorsten; Krause, Eva; Brune, Wolfram; Angulo, Ana; Ghazal, Peter

    2015-04-01

    Viral engagement with macrophages activates Toll-Like-Receptors (TLRs) and viruses must contend with the ensuing inflammatory responses to successfully complete their replication cycle. To date, known counter-strategies involve the use of viral-encoded proteins that often employ mimicry mechanisms to block or redirect the host response to benefit the virus. Whether viral regulatory DNA sequences provide an opportunistic strategy by which viral enhancer elements functionally mimic innate immune enhancers is unknown. Here we find that host innate immune genes and the prototypical viral enhancer of cytomegalovirus (CMV) have comparable expression kinetics, and positively respond to common TLR agonists. In macrophages but not fibroblasts we show that activation of NFκB at immediate-early times of infection is independent of virion-associated protein, M45. We find upon virus infection or transfection of viral genomic DNA the TLR-agonist treatment results in significant enhancement of the virus transcription-replication cycle. In macrophage time-course infection experiments we demonstrate that TLR-agonist stimulation of the viral enhancer and replication cycle is strictly delimited by a temporal gate with a determined half-maximal time for enhancer-activation of 6 h; after which TLR-activation blocks the viral transcription-replication cycle. By performing a systematic siRNA screen of 149 innate immune regulatory factors we identify not only anticipated anti-viral and pro-viral contributions but also new factors involved in the CMV transcription-replication cycle. We identify a central convergent NFκB-SP1-RXR-IRF axis downstream of TLR-signalling. Activation of the RXR component potentiated direct and indirect TLR-induced activation of CMV transcription-replication cycle; whereas chromatin binding experiments using wild-type and enhancer-deletion virus revealed IRF3 and 5 as new pro-viral host transcription factor interactions with the CMV enhancer in macrophages. In a

  20. A temporal gate for viral enhancers to co-opt Toll-like-receptor transcriptional activation pathways upon acute infection.

    Directory of Open Access Journals (Sweden)

    Kai A Kropp

    2015-04-01

    Full Text Available Viral engagement with macrophages activates Toll-Like-Receptors (TLRs and viruses must contend with the ensuing inflammatory responses to successfully complete their replication cycle. To date, known counter-strategies involve the use of viral-encoded proteins that often employ mimicry mechanisms to block or redirect the host response to benefit the virus. Whether viral regulatory DNA sequences provide an opportunistic strategy by which viral enhancer elements functionally mimic innate immune enhancers is unknown. Here we find that host innate immune genes and the prototypical viral enhancer of cytomegalovirus (CMV have comparable expression kinetics, and positively respond to common TLR agonists. In macrophages but not fibroblasts we show that activation of NFκB at immediate-early times of infection is independent of virion-associated protein, M45. We find upon virus infection or transfection of viral genomic DNA the TLR-agonist treatment results in significant enhancement of the virus transcription-replication cycle. In macrophage time-course infection experiments we demonstrate that TLR-agonist stimulation of the viral enhancer and replication cycle is strictly delimited by a temporal gate with a determined half-maximal time for enhancer-activation of 6 h; after which TLR-activation blocks the viral transcription-replication cycle. By performing a systematic siRNA screen of 149 innate immune regulatory factors we identify not only anticipated anti-viral and pro-viral contributions but also new factors involved in the CMV transcription-replication cycle. We identify a central convergent NFκB-SP1-RXR-IRF axis downstream of TLR-signalling. Activation of the RXR component potentiated direct and indirect TLR-induced activation of CMV transcription-replication cycle; whereas chromatin binding experiments using wild-type and enhancer-deletion virus revealed IRF3 and 5 as new pro-viral host transcription factor interactions with the CMV enhancer in

  1. The ethylene bis-dithiocarbamate fungicide Mancozeb activates voltage-gated KCNQ2 potassium channel.

    Science.gov (United States)

    Li, Ping; Zhu, Jin; Kong, Qingya; Jiang, Baifeng; Wan, Xia; Yue, Jinfeng; Li, Min; Jiang, Hualiang; Li, Jian; Gao, Zhaobing

    2013-06-07

    Mancozeb (manganese/zinc ethylene bis-dithiocarbamate) is an organometallic fungicide that has been associated with human neurotoxicity and neurodegeneration. In a high-throughput screen for modulators of KCNQ2 channel, a fundamental player modulating neuronal excitability, Mancozeb, was found to significantly potentiate KCNQ2 activity. Mancozeb was validated electrophysiologically as a KCNQ2 activator with an EC50 value of 0.92±0.23μM. Further examination showed that manganese but not zinc ethylene bis-dithiocarbamate is the active component for the positive modulation effects. In addition, the compounds are effective when the metal ions are substituted by iron but lack potentiation activity when the metal ions are substituted by sodium, signifying the importance of the metal ion. However, the iron (Fe(3+)) alone, organic ligands alone or the mixture of iron with the organic ligand did not show any potentiation effect, suggesting as the active ingredient is a specific complex rather than two separate additive or synergistic components. Our study suggests that potentiation on KCNQ2 potassium channels might be the possible mechanism of Mancozeb toxicity in the nervous system.

  2. Sunspot Rotation as a Driver of Major Solar Eruptions in the NOAA Active Region 12158

    Science.gov (United States)

    Vemareddy, P.; Cheng, X.; Ravindra, B.

    2016-09-01

    We studied the development conditions of sigmoid structure under the influence of the magnetic non-potential characteristics of a rotating sunspot in the active region (AR) 12158. Vector magnetic field measurements from the Helioseismic Magnetic Imager and coronal EUV observations from the Atmospheric Imaging Assembly reveal that the erupting inverse-S sigmoid had roots at the location of the rotating sunspot. The sunspot rotates at a rate of 0°-5° h-1 with increasing trend in the first half followed by a decrease. The time evolution of many non-potential parameters had a good correspondence with the sunspot rotation. The evolution of the AR magnetic structure is approximated by a time series of force-free equilibria. The non-linear force-free field magnetic structure around the sunspot manifests the observed sigmoid structure. Field lines from the sunspot periphery constitute the body of the sigmoid and those from the interior overlie the sigmoid, similar to a flux rope structure. While the sunspot was rotating, two major coronal mass ejection eruptions occurred in the AR. During the first (second) event, the coronal current concentrations were enhanced (degraded), consistent with the photospheric net vertical current; however, magnetic energy was released during both cases. The analysis results suggest that the magnetic connections of the sigmoid are driven by the slow motion of sunspot rotation, which transforms to a highly twisted flux rope structure in a dynamical scenario. Exceeding the critical twist in the flux rope probably leads to the loss of equilibrium, thus triggering the onset of the two eruptions.

  3. Differential regulation of voltage-gated Ca2+ currents and metabotropic glutamate receptor activity by measles virus infection in rat cortical neurons.

    Science.gov (United States)

    Günther, Christine; Laube, Mandy; Liebert, Uwe-Gerd; Kraft, Robert

    2012-01-06

    Measles virus (MV) infection may lead to severe chronic CNS disease processes, including MV-induced encephalitis. Because the intracellular Ca(2+) concentration ([Ca(2+)](i)) is a major determinant of the (patho-)physiological state in all cells we asked whether important Ca(2+) conducting pathways are affected by MV infection in cultured cortical rat neurons. Patch-clamp measurements revealed a decrease in voltage-gated Ca(2+) currents during MV-infection, while voltage-gated K(+) currents and NMDA-evoked currents were unaffected. Calcium-imaging experiments using 50mM extracellular KCl showed reduced [Ca(2+)](i) increases in MV-infected neurons, confirming a decreased activity of voltage-gated Ca(2+) channels. In contrast, the group-I metabotropic glutamate receptor (mGluR) agonist DHPG evoked changes in [Ca(2+)](i) that were increased in MV-infected cells. Our results show that MV infection conversely regulates Ca(2+) signals induced by group-I mGluRs and by voltage-gated Ca(2+) channels, suggesting that these physiological impairments may contribute to an altered function of cortical neurons during MV-induced encephalitis.

  4. ZD7288, a selective hyperpolarization-activated cyclic nucleotide-gated channel blocker, inhibits hippocampal synaptic plasticity

    Institute of Scientific and Technical Information of China (English)

    Xiao-xue Zhang; Xiao-chun Min; Xu-lin Xu; Min Zheng; Lian-jun Guo

    2016-01-01

    The selective hyperpolarization-activated cyclic nucleotide-gated (HCN) channel blocker 4-(N-ethyl-N-phenylamino)-1,2-dimeth-yl-6-(methylamino) pyrimidinium chloride (ZD7288) blocks the induction of long-term potentiation in the perforant path–CA3 region in rat hippocampusin vivo. To explore the mechanisms underlying the action of ZD7288, we recorded excitatory postsynaptic potentials in perforant path–CA3 synapses in male Sprague-Dawley rats. We measured glutamate content in the hippocampus and in cultured hip-pocampal neurons using high performance liquid chromatography, and determined intracellular Ca2+ concentration ([Ca2+]i) using Fura-2. ZD7288 inhibited the induction and maintenance of long-term potentiation, and these effects were mirrored by the nonspeciifc HCN channel blocker cesium. ZD7288 also decreased glutamate release in hippocampal tissue and in cultured hippocampal neurons. Further-more, ZD7288 attenuated glutamate-induced rises in [Ca2+]i in a concentration-dependent manner and reversed 8-Br-cAMP-mediated facilitation of these glutamate-induced [Ca2+]i rises. Our results suggest that ZD7288 inhibits hippocampal synaptic plasticity both gluta-mate release and resultant [Ca2+]i increases in rat hippocampal neurons.

  5. Steroid hormone regulation of the voltage-gated, calcium-activated potassium channel expression in developing muscular and neural systems.

    Science.gov (United States)

    Garrison, Sheldon L; Witten, Jane L

    2010-11-01

    A precise organization of gene expression is required for developing neural and muscular systems. Steroid hormones can control the expression of genes that are critical for development. In this study we test the hypothesis that the steroid hormone ecdysone regulates gene expression of the voltage-gated calcium-activated potassium ion channel, Slowpoke or KCNMA1. Late in adult development of the tobacco hawkmoth Manduca sexta, slowpoke (msslo) levels increased contributing to the maturation of the dorsal longitudinal flight muscles (DLMs) and CNS. We show that critical components of ecdysteroid gene regulation were present during upreglation of msslo in late adult DLM and CNS development. Ecdysteroid receptor complex heterodimeric partner proteins, the ecdysteroid receptor (EcR) and ultraspiracle (USP), and the ecdysone-induced early gene, msE75B, were expressed at key developmental time points, suggesting that ecdysteroids direct aspects of gene expression in the DLMs during these late developmental stages. We provide evidence that ecdysteroids suppress msslo transcription in the DLMs; when titers decline msslo transcript levels increase. These results are consistent with msslo being a downstream gene in an ecdysteroid-mediated gene cascade during DLM development. We also show that the ecdysteroids regulate msslo transcript levels in the developing CNS. These results will contribute to our understanding of how the spatiotemporal regulation of slowpoke transcription contributes to tailoring cell excitability to the differing physiological and behavioral demands during development.

  6. A light- and calcium-gated transcription factor for imaging and manipulating activated neurons.

    Science.gov (United States)

    Wang, Wenjing; Wildes, Craig P; Pattarabanjird, Tanyaporn; Sanchez, Mateo I; Glober, Gordon F; Matthews, Gillian A; Tye, Kay M; Ting, Alice Y

    2017-09-01

    Activity remodels neurons, altering their molecular, structural, and electrical characteristics. To enable the selective characterization and manipulation of these neurons, we present FLARE, an engineered transcription factor that drives expression of fluorescent proteins, opsins, and other genetically encoded tools only in the subset of neurons that experienced activity during a user-defined time window. FLARE senses the coincidence of elevated cytosolic calcium and externally applied blue light, which together produce translocation of a membrane-anchored transcription factor to the nucleus to drive expression of any transgene. In cultured rat neurons, FLARE gives a light-to-dark signal ratio of 120 and a high- to low-calcium signal ratio of 10 after 10 min of stimulation. Opsin expression permitted functional manipulation of FLARE-marked neurons. In adult mice, FLARE also gave light- and motor-activity-dependent transcription in the cortex. Due to its modular design, minute-scale temporal resolution, and minimal dark-state leak, FLARE should be useful for the study of activity-dependent processes in neurons and other cells that signal with calcium.

  7. The Conformation of Bound GMPPNP Suggests a Mechanism for Gating the Active Site of the SRP GTPase

    Energy Technology Data Exchange (ETDEWEB)

    Padmanabhan, S.; Freymann, D. (NWU)

    2010-03-08

    The signal recognition particle (SRP) is a phylogenetically conserved ribonucleoprotein that mediates cotranslational targeting of secreted and membrane proteins to the membrane. Targeting is regulated by GTP binding and hydrolysis events that require direct interaction between structurally homologous 'NG' GTPase domains of the SRP signal recognition subunit and its membrane-associated receptor, SR{alpha}. Structures of both the apo and GDP bound NG domains of the prokaryotic SRP54 homolog, Ffh, and the prokaryotic receptor homolog, FtsY, have been determined. The structural basis for the GTP-dependent interaction between the two proteins, however, remains unknown. We report here two structures of the NG GTPase of Ffh from Thermus aquaticus bound to the nonhydrolyzable GTP analog GMPPNP. Both structures reveal an unexpected binding mode in which the {beta}-phosphate is kinked away from the binding site and magnesium is not bound. Binding of the GTP analog in the canonical conformation found in other GTPase structures is precluded by constriction of the phosphate binding P loop. The structural difference between the Ffh complex and other GTPases suggests a specific conformational change that must accompany movement of the nucleotide from an inactive to an active binding mode. Conserved side chains of the GTPase sequence motifs unique to the SRP subfamily may function to gate formation of the active GTP bound conformation. Exposed hydrophobic residues provide an interaction surface that may allow regulation of the GTP binding conformation, and thus activation of the GTPase, during the association of SRP with its receptor.

  8. A Continuing Analysis of Possible Activity Drivers for the Enigmatic Comet 29P/Schwassmann-Wachmann 1

    Science.gov (United States)

    Schambeau, Charles; Fernández, Yanga; Samarasinha, Nalin H.; Mueller, Beatrice E. A.; Sarid, Gal; Meech, Karen Jean; Woodney, Laura

    2016-01-01

    We present results from our effort to understand activity drivers in Comet 29P/Schwassmann-Wachmann 1 (SW1). In a nearly circular orbit around 6 AU, outside of the water-sublimation zone, SW1 is continuously active and experiences frequent outbursts. Our group's effort is focusing on finding constraints on physical and dynamical properties of SW1's nucleus and their incorporation into a thermophysical model [1,2] to explain this behavior. We are currently analyzing coma morphology of SW1 before, during, and after outburst placing constraints on the spin-pole direction, spin period, and surface areas of activity. In addition, we are using the thermal model to investigate if the continuous activity comes from one or multiple processes, such as the release of trapped supervolatiles during the amorphous to crystalline (A-C) water ice phase transition and/or the direct sublimation of pockets of supervolatile ices. The supervolatile ices may be primordial or from the condensation of gases released during the A-C phase transition. To explain the possibly quasi-periodic but frequent outbursts, we are looking into subsurface cavities where internal pressures can build, reaching and exceeding surrounding material strengths [3,4] and/or thermal waves reaching a pocket of supervolatile ices, causing a rapid increase in the sublimation rate. For all these phenomena, the model is constrained by comparing the output dust mass loss rate and its variability with what has been observed through optical imaging of the comet at various points in its orbit. We will present preliminary thermal modeling of a homogeneous progenitor nucleus that evolves into a body showing internal material layering, the generation of CO and CO2 ice pockets, and the production of outbursts, thus bringing us closer to explaining the behavior of this intriguing comet. [1] Sarid, G., et al.: 2005, PASP, 117, 843. [2] Sarid, G.: 2009, PhD Thesis, Tel Aviv Univ. [3] Gronkowski, P., 2014, Astron. Nachr./AN 2, No

  9. New Incremental Actuators based on Electro-active Polymer: Conceptual, Control, and Driver Design Considerations

    DEFF Research Database (Denmark)

    Thummala, Prasanth; Schneider, Henrik; Zhang, Zhe

    2016-01-01

    incrementalactuator. The DEAP incremental actuator consists of threeindependent DEAP actuators with a unique cylindrical designthat potentially simplifies mass production and scalabilitycompared to existing DEAP actuators. To accomplish theincremental motion, a high voltage (HV) bidirectional DC......-DCconverter, independently charges and discharges each capacitiveDEAP actuator. The topology used for the HV driver is a peakcurrent controlled bidirectional flyback converter. Thescalability of the proposed DEAP incremental actuator isdiscussed, and different scaled designs are provided. Theestimated speeds and forces...... for various scaled incrementalactuator designs are provided. The HV drivers areexperimentally tested with a prototype of the DEAP incrementalactuator. The energy efficiency measurement results of one of theHV driver are presented. The DEAP incremental actuatorprototype achieved bidirectional motion...

  10. Electro-optic modulation methods in range-gated active imaging.

    Science.gov (United States)

    Chen, Zhen; Liu, Bo; Liu, Enhai; Peng, Zhangxian

    2016-01-20

    A time-resolved imaging method based on electro-optic modulation is proposed in this paper. To implement range resolution, two kinds of polarization-modulated methods are designed, and high spatial and range resolution can be achieved by the active imaging system. In the system, with polarization beam splitting the incident light is split into two parts, one of which is modulated with cos(2) function and the other is modulated with sin(2) function. Afterward, a depth map can be obtained from two simultaneously received images by dual electron multiplying charge-coupled devices. Furthermore, an intensity image can also be obtained from the two images. Comparisons of the two polarization-modulated methods indicate that range accuracy will be promoted when the polarized light is modulated before beam splitting.

  11. Inflammatory and neuropathic pain are rapidly suppressed by peripheral block of hyperpolarisation-activated cyclic nucleotide-gated ion channels.

    Science.gov (United States)

    Young, Gareth T; Emery, Edward C; Mooney, Elizabeth R; Tsantoulas, Christoforos; McNaughton, Peter A

    2014-09-01

    Previous studies have shown that hyperpolarisation-activated cyclic nucleotide-gated (HCN)-2 ion channels regulate the firing frequency of nociceptive sensory neurons and thus play a central role in both inflammatory and neuropathic pain conditions. Here we use ivabradine, a clinically approved anti-anginal agent that blocks all HCN channel isoforms approximately equally, to investigate the effect on inflammatory and neuropathic pain of HCN ion channel block. We show that ivabradine does not have major off-target effects on a sample group of Na, Ca, and K ion channels, and that it is peripherally restricted because it is a substrate for the P-glycoprotein (PgP) multidrug transporter that is expressed in the blood-brain barrier. Its effects are therefore likely to be due to an action on HCN ion channels in peripheral sensory neurons. Using patch clamp electrophysiology, we found that ivabradine was a use-dependent blocker of native HCN channels expressed in small sensory neurons. Ivabradine suppressed the action potential firing that is induced in nociceptive neurons by elevation of intracellular cAMP. In the formalin model of inflammatory pain, ivabradine reduced pain behaviour only in the second (inflammatory) phase. In nerve injury and chemotherapy models of neuropathic pain, we observed rapid and effective analgesia as effective as that with gabapentin. We conclude that both inflammatory and neuropathic pain are rapidly inhibited by blocking HCN-dependent repetitive firing in peripheral nociceptive neurons. Copyright © 2014 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

  12. Neuron-restrictive silencer factor-mediated hyperpolarization-activated cyclic nucleotide gated channelopathy in experimental temporal lobe epilepsy.

    Science.gov (United States)

    McClelland, Shawn; Flynn, Corey; Dubé, Celine; Richichi, Cristina; Zha, Qinqin; Ghestem, Antoine; Esclapez, Monique; Bernard, Christophe; Baram, Tallie Z

    2011-09-01

    Enduring, abnormal expression and function of the ion channel hyperpolarization-activated cyclic adenosine monophosphate gated channel type 1 (HCN1) occurs in temporal lobe epilepsy (TLE). We examined the underlying mechanisms, and investigated whether interfering with these mechanisms could modify disease course. Experimental TLE was provoked by kainic acid-induced status epilepticus (SE). HCN1 channel repression was examined at mRNA, protein, and functional levels. Chromatin immunoprecipitation was employed to identify the transcriptional mechanism of repressed HCN1 expression, and the basis for their endurance. Physical interaction of the repressor, NRSF, was abolished using decoy oligodeoxynucleotides (ODNs). Video/electroencephalographic recordings were performed to assess the onset and initial pattern of spontaneous seizures. Levels of NRSF and its physical binding to the Hcn1 gene were augmented after SE, resulting in repression of HCN1 expression and HCN1-mediated currents (I(h) ), and reduced I(h) -dependent resonance in hippocampal CA1 pyramidal cell dendrites. Chromatin changes typical of enduring, epigenetic gene repression were apparent at the Hcn1 gene within a week after SE. Administration of decoy ODNs comprising the NRSF DNA-binding sequence (neuron restrictive silencer element [NRSE]), in vitro and in vivo, reduced NRSF binding to Hcn1, prevented its repression, and restored I(h) function. In vivo, decoy NRSE ODN treatment restored theta rhythm and altered the initial pattern of spontaneous seizures. Acquired HCN1 channelopathy derives from NRSF-mediated transcriptional repression that endures via chromatin modification and may provide insight into the mechanisms of a number of channelopathies that coexist with, and may contribute to, the conversion of a normal brain into an epileptic one. Copyright © 2011 American Neurological Association.

  13. Time-driven activity-based costing: a driver for provider engagement in costing activities and redesign initiatives.

    Science.gov (United States)

    McLaughlin, Nancy; Burke, Michael A; Setlur, Nisheeta P; Niedzwiecki, Douglas R; Kaplan, Alan L; Saigal, Christopher; Mahajan, Aman; Martin, Neil A; Kaplan, Robert S

    2014-11-01

    To date, health care providers have devoted significant efforts to improve performance regarding patient safety and quality of care. To address the lagging involvement of health care providers in the cost component of the value equation, UCLA Health piloted the implementation of time-driven activity-based costing (TDABC). Here, the authors describe the implementation experiment, share lessons learned across the care continuum, and report how TDABC has actively engaged health care providers in costing activities and care redesign. After the selection of pilots in neurosurgery and urology and the creation of the TDABC team, multidisciplinary process mapping sessions, capacity-cost calculations, and model integration were coordinated and offered to engage care providers at each phase. Reviewing the maps for the entire episode of care, varying types of personnel involved in the delivery of care were noted: 63 for the neurosurgery pilot and 61 for the urology pilot. The average cost capacities for care coordinators, nurses, residents, and faculty were $0.70 (range $0.63-$0.75), $1.55 (range $1.28-$2.04), $0.58 (range $0.56-$0.62), and $3.54 (range $2.29-$4.52), across both pilots. After calculating the costs for material, equipment, and space, the TDABC model enabled the linking of a specific step of the care cycle (who performed the step and its duration) and its associated costs. Both pilots identified important opportunities to redesign care delivery in a costconscious fashion. The experimentation and implementation phases of the TDABC model have succeeded in engaging health care providers in process assessment and costing activities. The TDABC model proved to be a catalyzing agent for cost-conscious care redesign.

  14. Synchronized network activity in developing rat hippocampus involves regional hyperpolarization-activated cyclic nucleotide-gated (HCN) channel function

    OpenAIRE

    Bender, Roland A.; Galindo, Rafael; Mameli, Manuel; Gonzalez-Vega, Rebeca; Valenzuela, C. Fernando; Tallie Z. Baram

    2005-01-01

    The principal form of synchronized network activity in neonatal hippocampus consists of low frequency ‘giant depolarizing potentials’ (GDPs). Whereas contribution of both GABA and glutamate to their generation has been demonstrated, full understanding of the mechanisms underlying these synchronized activity bursts remains incomplete. A contribution of the h-current, conducted by HCN channels, to GDPs has been a topic of substantial interest. Here we focus on HCN1, the prevalent HCN channel is...

  15. SUMOylation of the Hyperpolarization-Activated Cyclic Nucleotide-Gated Channel 2 Increases Surface Expression and the Maximal Conductance of the Hyperpolarization-Activated Current

    Science.gov (United States)

    Parker, Anna R.; Welch, Meghyn A.; Forster, Lori A.; Tasneem, Sarah M.; Dubhashi, Janhavi A.; Baro, Deborah J.

    2017-01-01

    Small Ubiquitin-like Modifier (SUMO) is a ∼10 kDa peptide that can be post-translationally added to a lysine (K) on a target protein to facilitate protein–protein interactions. Recent studies have found that SUMOylation can be regulated in an activity-dependent manner and that ion channel SUMOylation can alter the biophysical properties and surface expression of the channel. Hyperpolarization-activated cyclic nucleotide-gated (HCN) channel surface expression can be regulated in an activity-dependent manner through unknown processes. We hypothesized that SUMOylation might influence the surface expression of HCN2 channels. In this manuscript, we show that HCN2 channels are SUMOylated in the mouse brain. Baseline levels of SUMOylation were also observed for a GFP-tagged HCN2 channel stably expressed in Human embryonic kidney (Hek) cells. Elevating GFP-HCN2 channel SUMOylation above baseline in Hek cells led to an increase in surface expression that augmented the hyperpolarization-activated current (Ih) mediated by these channels. Increased SUMOylation did not alter Ih voltage-dependence or kinetics of activation. There are five predicted intracellular SUMOylation sites on HCN2. Site-directed mutagenesis indicated that more than one K on the GFP-HCN2 channel was SUMOylated. Enhancing SUMOylation at one of the five predicted sites, K669, led to the increase in surface expression and Ih Gmax. The role of SUMOylation at additional sites is currently unknown. The SUMOylation site at K669 is also conserved in HCN1 channels. Aberrant SUMOylation has been linked to neurological diseases that also display alterations in HCN1 and HCN2 channel expression, such as seizures and Parkinson’s disease. This work is the first report that HCN channels can be SUMOylated and that this can regulate surface expression and Ih. PMID:28127275

  16. Quantum Gates and Circuits

    CERN Document Server

    Di Vincenzo, D P

    1997-01-01

    A historical review is given of the emergence of the idea of the quantum logic gate from the theory of reversible Boolean gates. I highlight the quantum XOR or controlled NOT as the fundamental two-bit gate for quantum computation. This gate plays a central role in networks for quantum error correction.

  17. On the Response of Polar Cap Dynamics to Its Solar Wind and Magnetotail Drivers at High Levels of Geomagnetic Activity

    Science.gov (United States)

    Gao, Ye

    In this thesis, I investigate how polar cap dynamics, quantified by the northern polar cap (PCN) index, respond to solar wind direct driving and magnetotail energy unloading during intervals of strong solar wind driving. Using 53 one to two-day intervals with high cross polar cap potential subintervals, I find that, among 11 candidate coupling functions including the electric field of Kan and Lee (1979) and the universal coupling function of Newell et al. (2007), the PCN index correlates most closely with the electric field (EK-R) of Kivelson and Ridley (2008), a form in which the electric field imposed on the ionosphere by low-latitude magnetopause reconnection saturates at high levels of geomagnetic activity. It is found that magnetotail activity, as represented by an unloading AL index (ALU), makes a significant contribution to the PCN index. A linear model is constructed to relate the PCN index to its solar wind and magnetotail drivers. Based on this model, it is estimated that the portion of the PCN index directly driven by the solar wind electric field outweighs the contribution arising from energy release in the magnetotail by roughly a factor of 2. The solar wind dynamic pressure (pdyn) does not play a key role in controlling the PCN index. However, under intense solar wind driving, the number density (n) can influence the solar wind-magnetosphere coupling by changing the solar wind Alfvén conductance, which is incorporated in EK-R. The validity of the linear model is verified by comparing its results with those obtained from a more general, non-linear model, termed additive model. It is found that, except in anomalous events during which the auroral oval expanded poleward to the latitude of the PCN index station and the index increased because of proximity to auroral zone currents, the linear model is a good approximation, since more than 70% of the variation in the PCN index is explained by the linear model. Thus, this linear model provides a useful tool

  18. Neurotoxic activity of venom from the Australian eastern mouse spider (Missulena bradleyi) involves modulation of sodium channel gating.

    Science.gov (United States)

    Rash, L D; Birinyi-Strachan, L C; Nicholson, G M; Hodgson, W C

    2000-08-01

    Mouse spiders represent a potential cause of serious envenomation in humans. This study examined the activity of Missulena bradleyi venom in several in vitro preparations. Whilst female M. bradleyi venom at doses up to 0.05 microl ml(-1) failed to alter twitch or resting tension in all preparations used, male venom (0.02 and 0.05 microl ml(-1)) produced potent effects on transmitter release in both smooth and skeletal neuromuscular preparations. In the mouse phrenic nerve diaphragm preparation, male M. bradleyi venom (0.02 microl ml(-1)) caused rapid fasciculations and an increase in indirectly evoked twitches. Male venom (0.02 and 0.05 microl ml(-1)) also caused a large contracture and rapid decrease in indirectly evoked twitches in the chick biventer cervicis muscle, however had no effect on responses to exogenous ACh (1 mM) or potassium chloride (40 mM). In the chick preparation, contractile responses to male M. bradleyi venom (0.05 microl ml(-1)) were attenuated by (+)-tubocurarine (100 microM) and by tetrodotoxin (TTX, 1 microM). Both actions of male M. bradleyi venom were blocked by Atrax robustus antivenom (2 units ml(-1)). In the unstimulated rat vas deferens, male venom (0.05 microl ml(-1)) caused contractions which were inhibited by a combination of prazosin (0.3 microM) and P(2X)-receptor desensitization (with alpha,beta-methylene ATP 10 microM). In the rat stimulated vas deferens, male venom (0.05 microl ml(-1)) augmented indirectly evoked twitches. Male venom (0.1 microl ml(-1)) causes a slowing of inactivation of TTX-sensitive sodium currents in acutely dissociated rat dorsal root ganglion neurons. These results suggest that venom from male M. bradleyi contains a potent neurotoxin which facilitates neurotransmitter release by modifying TTX-sensitive sodium channel gating. This action is similar to that of the delta-atracotoxins from Australian funnel-web spiders.

  19. Ginsenoside Rb1 selectively inhibits the activity of L-type voltage-gated calcium channels in cultured rat hippocampal neurons

    Institute of Scientific and Technical Information of China (English)

    Zhi-ying LIN; Li-min CHEN; Jing ZHANG; Xiao-dong PAN; Yuan-gui ZHU; Qin-yong YE; Hua-pin HUANG; Xiao-chun CHEN

    2012-01-01

    Aim:To investigate the effect of ginsenoside Rb1 on voltage-gated calcium currents in cultured rat hippocampal neurons and the modulatory mechanism.Methods:Cultured hippocampal neurons were prepared from Sprague Dawley rat embryos.Whole-cell configuration of the patchclamp technique was used to record the voltage-gated calcium currents (VGCCs)from the hippocampal neurons,and the effect of Rb1 was examined.Results:Rb1 (2-100 μmol/L)inhibited VGCCs in a concentration-dependent manner,and the current was mostly recovered upon wash-out.The specific L-type Ca2+ channel inhibitor nifedipine (10 μmol/L)occluded Rb1-induced inhibition on VGCCs.Neither the selective N-type Ca2+ channel blocker ω-conotoxin-GVlA (1 μmoVL),nor the selective P/Q-type Ca2+ channel blocker ωo-agatoxin IVA (30 nmol/L)diminished Rb1-sensitive VGCCs.Rb1 induced a leftward shift of the steady-state inactivation curve of Ica to a negative potential without affecting its activation kinetics or reversal potential in the I-V curve.The inhibitory effect of Rb1 was neither abolished by the adenylyl cyclase activator forskolin (10 μmol/L),nor by the PKA inhibitor H-89 (10 μmol/L).Conclusion:Ginsenoside Rb1 selectively inhibits the activity of L-type voltage-gated calcium channels,without affecting the N-type or P/Q-type Ca2+ channels in hippocampal neurons,cAMP-PKA signaling pathway is not involved in this effect.

  20. NAND GATE USING FINFET FOR NANOSCALE TECHNOLOGY

    Directory of Open Access Journals (Sweden)

    Nirmal,

    2010-05-01

    Full Text Available In this paper we propose Double gate transistors (FinFETs are the substitutes for bulk CMOS evolving from a single gate devices into three dimensional devices with multiple gates (double gate, triple gate or quadruple-gate devices. The main drawback of using CMOS transistors are high power consumption and high leakage current. Enormous progress has been made to scale transistors to even smaller dimensions to obtain fast switching transistors, as well as to reduce the power consumption. Even though the device characteristics are improved, high active leakage remain a problem. Leakage is found to contribute more amount of total power consumption in power-optimized FinFET logic circuits. This paper mainly deals with the various logic design styles to obtain the Leakage power savings through the judicious use of FinFET logic styles.

  1. Structure of membrane-active toxin from crab spider Heriaeus melloteei suggests parallel evolution of sodium channel gating modifiers in Araneomorphae and Mygalomorphae.

    Science.gov (United States)

    Berkut, Antonina A; Peigneur, Steve; Myshkin, Mikhail Yu; Paramonov, Alexander S; Lyukmanova, Ekaterina N; Arseniev, Alexander S; Grishin, Eugene V; Tytgat, Jan; Shenkarev, Zakhar O; Vassilevski, Alexander A

    2015-01-01

    We present a structural and functional study of a sodium channel activation inhibitor from crab spider venom. Hm-3 is an insecticidal peptide toxin consisting of 35 amino acid residues from the spider Heriaeus melloteei (Thomisidae). We produced Hm-3 recombinantly in Escherichia coli and determined its structure by NMR spectroscopy. Typical for spider toxins, Hm-3 was found to adopt the so-called "inhibitor cystine knot" or "knottin" fold stabilized by three disulfide bonds. Its molecule is amphiphilic with a hydrophobic ridge on the surface enriched in aromatic residues and surrounded by positive charges. Correspondingly, Hm-3 binds to both neutral and negatively charged lipid vesicles. Electrophysiological studies showed that at a concentration of 1 μm Hm-3 effectively inhibited a number of mammalian and insect sodium channels. Importantly, Hm-3 shifted the dependence of channel activation to more positive voltages. Moreover, the inhibition was voltage-dependent, and strong depolarizing prepulses attenuated Hm-3 activity. The toxin is therefore concluded to represent the first sodium channel gating modifier from an araneomorph spider and features a "membrane access" mechanism of action. Its amino acid sequence and position of the hydrophobic cluster are notably different from other known gating modifiers from spider venom, all of which are described from mygalomorph species. We hypothesize parallel evolution of inhibitor cystine knot toxins from Araneomorphae and Mygalomorphae suborders.

  2. New gate opening hours

    CERN Multimedia

    GS Department

    2009-01-01

    Please note the new opening hours of the gates as well as the intersites tunnel from the 19 May 2009: GATE A 7h - 19h GATE B 24h/24 GATE C 7h - 9h\t17h - 19h GATE D 8h - 12h\t13h - 16h GATE E 7h - 9h\t17h - 19h Prévessin 24h/24 The intersites tunnel will be opened from 7h30 to 18h non stop. GS-SEM Group Infrastructure and General Services Department

  3. Driver Behavior and Motivation.

    Science.gov (United States)

    Thomas, Patricia

    School bus driver behavior and motivation are continuing concerns for leaders/administrators in the field of transportation. Motivation begins with selection of a potential new driver. Drivers must like children and be patient, loyal, and punctual. The applicant's background must be verified, in view of the national concern for child safety.…

  4. Deletion of cytosolic gating ring decreases gate and voltage sensor coupling in BK channels.

    Science.gov (United States)

    Zhang, Guohui; Geng, Yanyan; Jin, Yakang; Shi, Jingyi; McFarland, Kelli; Magleby, Karl L; Salkoff, Lawrence; Cui, Jianmin

    2017-03-06

    Large conductance Ca(2+)-activated K(+) channels (BK channels) gate open in response to both membrane voltage and intracellular Ca(2+) The channel is formed by a central pore-gate domain (PGD), which spans the membrane, plus transmembrane voltage sensors and a cytoplasmic gating ring that acts as a Ca(2+) sensor. How these voltage and Ca(2+) sensors influence the common activation gate, and interact with each other, is unclear. A previous study showed that a BK channel core lacking the entire cytoplasmic gating ring (Core-MT) was devoid of Ca(2+) activation but retained voltage sensitivity (Budelli et al. 2013. Proc. Natl. Acad. Sci. USA http://dx.doi.org/10.1073/pnas.1313433110). In this study, we measure voltage sensor activation and pore opening in this Core-MT channel over a wide range of voltages. We record gating currents and find that voltage sensor activation in this truncated channel is similar to WT but that the coupling between voltage sensor activation and gating of the pore is reduced. These results suggest that the gating ring, in addition to being the Ca(2+) sensor, enhances the effective coupling between voltage sensors and the PGD. We also find that removal of the gating ring alters modulation of the channels by the BK channel's β1 and β2 subunits.

  5. Activation of theMercury Laser System: A Diode-Pumped Solid-State Laser Driver for Inertial Fusion

    Energy Technology Data Exchange (ETDEWEB)

    Bayramian, A J; Beach, R J; Bibeau, C; Ebbers, C A; Freitas, B L; Kanz, V K; Payne, S A; Schaffers, K I; Skulina, K M; Smith, L K; Tassano, J B

    2001-09-10

    Initial measurements are reported for the Mercury laser system, a scalable driver for rep-rated inertial fusion energy. The performance goals include 10% electrical efficiency at 10 Hz and 100 J with a 2-10 ns pulse length. We report on the first Yb:S-FAP crystals grown to sufficient size for fabricating full size (4 x 6 cm) amplifier slabs. The first of four 160 kW (peak power) diode arrays and pump delivery systems were completed and tested with the following results: 5.5% power droop over a 0.75 ms pulse, 3.95 nm spectral linewidth, far field divergence of 14.0 mrad and 149.5 mrad in the microlensed and unmicrolensed directions respectively, and 83% optical-to-optical transfer efficiency through the pump delivery system.

  6. Diel activity patterns of juvenile late fall-run Chinook salmon with implications for operation of a gated water diversion in the Sacramento–San Joaquin River Delta

    Science.gov (United States)

    Plumb, John M.; Adams, Noah S.; Perry, Russell W.; Holbrook, Christopher; Romine, Jason G.; Blake, Aaron R.; Burau, Jon R.

    2016-01-01

    In the Sacramento-San Joaquin River Delta, California, tidal forces that reverse river flows increase the proportion of water and juvenile late fall-run Chinook salmon diverted into a network of channels that were constructed to support agriculture and human consumption. This area is known as the interior delta, and it has been associated with poor fish survival. Under the rationale that the fish will be diverted in proportion to the amount of water that is diverted, the Delta Cross Channel (DCC) has been prescriptively closed during the winter out-migration to reduce fish entrainment and mortality into the interior delta. The fish are thought to migrate mostly at night, and so daytime operation of the DCC may allow for water diversion that minimizes fish entrainment and mortality. To assess this, the DCC gate was experimentally opened and closed while we released 2983 of the fish with acoustic transmitters upstream of the DCC to monitor their arrival and entrainment into the DCC. We used logistic regression to model night-time arrival and entrainment probabilities with covariates that included the proportion of each diel period with upstream flow, flow, rate of change in flow and water temperature. The proportion of time with upstream flow was the most important driver of night-time arrival probability, yet river flow had the largest effect on fish entrainment into the DCC. Modelling results suggest opening the DCC during daytime while keeping the DCC closed during night-time may allow for water diversion that minimizes fish entrainment into the interior delta.

  7. Intelligent Speed Adaptation for involuntary drivers

    DEFF Research Database (Denmark)

    Agerholm, Niels; Tradisauskas, Nerius; Juhl, Jens

    2012-01-01

    The Danish Intelligent Speed Adaptation (ISA) trial ISA C included 26 commercial cars and 51 drivers a number of whom were involuntary. After a baseline period, ISA was activated for one year. The drivers should identify themselves with a personal key ID before driving. As well as being informative...

  8. Switched mode piezo-panel driver

    NARCIS (Netherlands)

    Slakhorst, R.J.

    2007-01-01

    Abstract The subject of this thesis is the design of a system which can drive piezo-panels. This system is called the piezo driver. The piezo-panels are used for an Active Noise Cancelling (ANC) system which is being developed to be used inside the cabin of airplanes. The piezo driver fills the gap

  9. Technology and teen drivers.

    Science.gov (United States)

    Lee, John D

    2007-01-01

    The rapid evolution of computing, communication, and sensor technology is likely to affect young drivers more than others. The distraction potential of infotainment technology stresses the same vulnerabilities that already lead young drivers to crash more frequently than other drivers. Cell phones, text messaging, MP3 players, and other nomadic devices all present a threat because young drivers may lack the spare attentional capacity for vehicle control and the ability to anticipate and manage hazards. Moreover, young drivers are likely to be the first and most aggressive users of new technology. Fortunately, emerging technology can also support safe driving. Electronic stability control, collision avoidance systems, intelligent speed adaptation, and vehicle tracking systems can all help mitigate the threats to young drivers. However, technology alone is unlikely to make young drivers safer. One promising approach to tailoring technology to teen drivers is to extend proven methods for enhancing young driver safety. The success of graduated drivers license programs (GDL) and the impressive safety benefit of supervised driving suggest ways of tailoring technology to the needs of young drivers. To anticipate the effects of technology on teen driving it may be useful to draw an analogy between the effects of passengers and the effects of technology. Technology can act as a teen passenger and undermine safety or it can act as an adult passenger and enhance safety. Rapidly developing technology may have particularly large effects on teen drivers. To maximize the positive effects and minimize the negative effects will require a broad range of industries to work together. Ideally, vehicle manufacturers would work with infotainment providers, insurance companies, and policy makers to craft new technologies so that they accommodate the needs of young drivers. Without such collaboration young drivers will face even greater challenges to their safety as new technologies emerge.

  10. Genetic variation in Hyperpolarization-activated cyclic nucleotide-gated (HCN channels and its relationship with neuroticism, cognition and risk of depression

    Directory of Open Access Journals (Sweden)

    Andrew Mark Mcintosh

    2012-07-01

    Full Text Available Hyperpolarization-activated cyclic nucleotide-gated (HCN channels are encoded by four genes (HCN1-4 and, through activation by cyclic AMP (cAMP, represent a point of convergence for several psychosis risk genes. On the basis of positive preliminary data, we sought to test whether genetic variation in HCN1-4 conferred risk of depression or cognitive impairment in the Generation Scotland: Scottish Family Health Study. HCN1, HCN2, HCN3 and HCN4 were genotyped for 43 haplotype-tagging SNPs and tested for association with DSM-IV depression, neuroticism and a battery of cognitive tests assessing cognitive ability, memory, verbal fluency and psychomotor performance. No association was found between any HCN channel gene SNP and risk of depression, neuroticism or on any cognitive measure. The current study does not support a genetic role for HCN channels in conferring risk of depression or cognitive impairment in human subjects within the Scottish population.

  11. High-frequency detection of cell activity of Physarum polycephalum by a planar open gate AlGaN/GaN HEMT

    Science.gov (United States)

    Witte, Hartmut; Lippelt, Thomas; Warnke, Christian; Dadgar, Armin; Hauser, Marcus J. B.; Krost, Alois

    2014-10-01

    The dynamics of cells of the slime mould Physarum polycephalum are investigated with a planar AlGaN/GaN high electron mobility transistor (HEMT) without any gate metallization. The source-drain contacts are used in a two-electrode arrangement whereas the free gate surface area is occupied by the Physarum cell. In order to understand the measured signals, basic properties of the interface between the cell and the HEMT surface were analysed by impedance spectroscopy. At high frequencies the interface impedance is governed by the conductance of the cell due to a direct current through the HEMT/cell interface. The locomotive dynamics of Physarum were recorded by the source-drain impedance at 10 kHz in combination with simultaneous video imaging that monitored the degree of occupancy of the HEMT surface by the cell. A precise correlation was found between the impedance and the coverage of the HEMT surface by the cell. It is observed that the entire region between the contacts is sensitive to the cell activity. Well-resolved cellular oscillations were observed for all measured parameters. Their periods corresponded to the typical periods of the intracellular shuttle streaming of protoplasma in Physarum. This demonstrates that high-frequency impedance measurements with AlGaN/GaN HEMT structures are well suited for the analysis of both the static parts of single Physarum cells as well as of their dynamic behaviour, such as their expansion and motility.

  12. Electromagnetic fields act via activation of voltage-gated calcium channels to produce beneficial or adverse effects.

    Science.gov (United States)

    Pall, Martin L

    2013-08-01

    The direct targets of extremely low and microwave frequency range electromagnetic fields (EMFs) in producing non-thermal effects have not been clearly established. However, studies in the literature, reviewed here, provide substantial support for such direct targets. Twenty-three studies have shown that voltage-gated calcium channels (VGCCs) produce these and other EMF effects, such that the L-type or other VGCC blockers block or greatly lower diverse EMF effects. Furthermore, the voltage-gated properties of these channels may provide biophysically plausible mechanisms for EMF biological effects. Downstream responses of such EMF exposures may be mediated through Ca(2+) /calmodulin stimulation of nitric oxide synthesis. Potentially, physiological/therapeutic responses may be largely as a result of nitric oxide-cGMP-protein kinase G pathway stimulation. A well-studied example of such an apparent therapeutic response, EMF stimulation of bone growth, appears to work along this pathway. However, pathophysiological responses to EMFs may be as a result of nitric oxide-peroxynitrite-oxidative stress pathway of action. A single such well-documented example, EMF induction of DNA single-strand breaks in cells, as measured by alkaline comet assays, is reviewed here. Such single-strand breaks are known to be produced through the action of this pathway. Data on the mechanism of EMF induction of such breaks are limited; what data are available support this proposed mechanism. Other Ca(2+) -mediated regulatory changes, independent of nitric oxide, may also have roles. This article reviews, then, a substantially supported set of targets, VGCCs, whose stimulation produces non-thermal EMF responses by humans/higher animals with downstream effects involving Ca(2+) /calmodulin-dependent nitric oxide increases, which may explain therapeutic and pathophysiological effects.

  13. Search after new agents for hyperpolarization-activated and cyclic nucleotide-gated ion channels; Suche nach neuen Wirkstoffen fuer Hyperpolarisationsaktivierte und zyklisch Nukleotid-gesteuerte Ionenkanaele

    Energy Technology Data Exchange (ETDEWEB)

    Struenker, T.

    2005-12-01

    Rhythmic activity of single cells or cellular networks is a common feature of most organisms. Cellular rhythms govern the beating of the heart, cycles of sleep and wakefulness, breathing, and the release of hormones. The endogenous rhythmic activity of many neurons and cardiac relies on a complex interplay between several distinct ion channels. In particular, one type of ion channel plays a prominent role in the control of rhythmic electrical activity because it determines the frequency of the oscillations. The activity of the channels is thus setting the ''pace'' of the activity; therefore, these channels are often referred to as ''pacemaker'' channels. Despite their obvious physiological importance it hasn't been until a few years ago that the genes encoding pacemaker channels have been identified. Because both hyperpolarization and cyclic nucleotides are key elements that control their activity, pacemaker channels have now been designated hyperpolarization-activated and cyclic nucleotide-gated (HCN) channels. From a scientific as well as medical point of view, HCN channels are interesting drug targets. Only a few substances are known that specifically affect HCN channels. In the present study, a microtiter plate-based high throughput screening assay for HCN1 and HCN4 channels was developed. With this assay, known drugs for HCN channels were characterized. Subsequently, venoms of snails, spiders, scorpions, and snakes were screened for toxins affecting HCN channel activity. A few venoms were identified that possibly contain drugs that act on HCN channels. (orig.)

  14. Spatiotemporal drivers of dissolved organic matter in high alpine lakes: Role of Saharan dust inputs and bacterial activity

    Science.gov (United States)

    Mladenov, Natalie; Pulido-Villena, Elvira; Morales-Baquero, Rafael; Ortega-Retuerta, Eva; Sommaruga, Ruben; Reche, Isabel

    2010-01-01

    The effects of many environmental stressors such as UV radiation are mediated by dissolved organic matter (DOM) properties. Therefore, determining the factors shaping spatial and temporal patterns is particularly essential in the most susceptible, low dissolved organic carbon (DOC) lakes. We analyzed spatiotemporal variations in dissolved organic carbon concentration and dissolved organic matter optical properties (absorption and fluorescence) in 11 transparent lakes located above tree line in the Sierra Nevada Mountains (Spain), and we assessed potential external (evaporation and atmospheric deposition) and internal (bacterial abundance, bacterial production, chlorophyll a, and catchment vegetation) drivers of DOM patterns. At spatial and temporal scales, bacteria were related to chromophoric DOM (CDOM). At the temporal scale, water soluble organic carbon (WSOC) in dust deposition and evaporation were found to have a significant influence on DOC and CDOM in two Sierra Nevada lakes studied during the ice-free periods of 2000–2002. DOC concentrations and absorption coefficients at 320 nm were strongly correlated over the spatial scale (n = 11, R2 = 0.86; p < 0.01), but inconsistently correlated over time, indicating seasonal and interannual variability in external factors and a differential response of DOC concentration and CDOM to these factors. At the continental scale, higher mean DOC concentrations and more CDOM in lakes of the Sierra Nevada than in lakes of the Pyrenees and Alps may be due to a combination of more extreme evaporation, and greater atmospheric dust deposition. PMID:20582227

  15. Source Driver Channel Reduction Schemes Employing Corresponding Pixel Alignments for Current Programming Active-Matrix Organic Light-Emitting Diode Displays

    Science.gov (United States)

    Hong, Soon-Kwang; Oh, Du-Hwan; Jeong, Seok-Hee; Park, Young-Ju; Kim, Byeong-Koo; Ha, Yong-Min; Jang, Jin

    2008-03-01

    We propose two types of novel scheme for reducing the number of output channels of driver-integrated circuit (D-IC) for the current programming compensation pixel structures of active-matrix organic light-emitting diodes (AMOLEDs). One is a 2:1 data demultiplexing technique that can reduce the number of output channels of D-IC by half. The proposed second scheme is a vertically aligned red (R), green (G), and blue (B) subpixel scheme instead of a horizontally aligned R-G-B subpixel one, which is regarded as the conventional pixel alignment scheme. We have also successfully implemented these schemes in a 2.4-in.-sized QCIF + (176 × RGB × 220) AMOLED using p-type excimer laser annealing (ELA) low-temperature polycrystalline silicon (LTPS) technology and evaluated key performance characteristics.

  16. A mechanism for the auto-inhibition of hyperpolarization-activated cyclic nucleotide-gated (HCN) channel opening and its relief by cAMP.

    Science.gov (United States)

    Akimoto, Madoka; Zhang, Zaiyong; Boulton, Stephen; Selvaratnam, Rajeevan; VanSchouwen, Bryan; Gloyd, Melanie; Accili, Eric A; Lange, Oliver F; Melacini, Giuseppe

    2014-08-01

    Hyperpolarization-activated cyclic nucleotide-gated (HCN) ion channels control neuronal and cardiac electrical rhythmicity. There are four homologous isoforms (HCN1-4) sharing a common multidomain architecture that includes an N-terminal transmembrane tetrameric ion channel followed by a cytoplasmic "C-linker," which connects a more distal cAMP-binding domain (CBD) to the inner pore. Channel opening is primarily stimulated by transmembrane elements that sense membrane hyperpolarization, although cAMP reduces the voltage required for HCN activation by promoting tetramerization of the intracellular C-linker, which in turn relieves auto-inhibition of the inner pore gate. Although binding of cAMP has been proposed to relieve auto-inhibition by affecting the structure of the C-linker and CBD, the nature and extent of these cAMP-dependent changes remain limitedly explored. Here, we used NMR to probe the changes caused by the binding of cAMP and of cCMP, a partial agonist, to the apo-CBD of HCN4. Our data indicate that the CBD exists in a dynamic two-state equilibrium, whose position as gauged by NMR chemical shifts correlates with the V½ voltage measured through electrophysiology. In the absence of cAMP, the most populated CBD state leads to steric clashes with the activated or "tetrameric" C-linker, which becomes energetically unfavored. The steric clashes of the apo tetramer are eliminated either by cAMP binding, which selects for a CBD state devoid of steric clashes with the tetrameric C-linker and facilitates channel opening, or by a transition of apo-HCN to monomers or dimer of dimers, in which the C-linker becomes less structured, and channel opening is not facilitated.

  17. The Extended Transmembrane Orai1 N-terminal (ETON) Region Combines Binding Interface and Gate for Orai1 Activation by STIM1*♦

    Science.gov (United States)

    Derler, Isabella; Plenk, Peter; Fahrner, Marc; Muik, Martin; Jardin, Isaac; Schindl, Rainer; Gruber, Hermann J.; Groschner, Klaus; Romanin, Christoph

    2013-01-01

    STIM1 and Orai1 represent the two molecular key components of the Ca2+ release-activated Ca2+ channels. Their activation involves STIM1 C terminus coupling to both the N terminus and the C terminus of Orai. Here we focused on the extended transmembrane Orai1 N-terminal (ETON, aa73–90) region, conserved among the Orai family forming an elongated helix of TM1 as recently shown by x-ray crystallography. To identify “hot spot” residues in the ETON binding interface for STIM1 interaction, numerous Orai1 constructs with N-terminal truncations or point mutations within the ETON region were generated. N-terminal truncations of the first four residues of the ETON region or beyond completely abolished STIM1-dependent Orai1 function. Loss of Orai1 function resulted from neither an impairment of plasma membrane targeting nor pore damage, but from a disruption of STIM1 interaction. In a complementary approach, we monitored STIM1-Orai interaction via Orai1 V102A by determining restored Ca2+ selectivity as a consequence of STIM1 coupling. Orai1 N-terminal truncations that led to a loss of function consistently failed to restore Ca2+ selectivity of Orai1 V102A in the presence of STIM1, demonstrating impairment of STIM1 binding. Hence, the major portion of the ETON region (aa76–90) is essential for STIM1 binding and Orai1 activation. Mutagenesis within the ETON region revealed several hydrophobic and basic hot spot residues that appear to control STIM1 coupling to Orai1 in a concerted manner. Moreover, we identified two basic residues, which protrude into the elongated pore to redound to Orai1 gating. We suggest that several hot spot residues in the ETON region contribute in aggregate to the binding of STIM1, which in turn is coupled to a conformational reorientation of the gate. PMID:23943619

  18. Gate of radioactivity detection. guide on the methodology to follow in the case of activating; Portique de detection de radioactivite. Guide sur la methodologie a suivre en cas de declenchement

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-07-01

    Most of operators of waste treatment centers are tooled up with gates of radioactivity detection. To meet to a need of clarification of procedures that can be followed during an activating of gates, cards have been established by a work group constituted by representatives of different entities concerned by the subject. These cards propose procedures to follow in the case of activating of gates in respecting the running legislation in the field of environment protection and radiation protection. Annexe with the terms mentioned in the cards are given, a lexicon on radioactivity and a list of organisms able and licensed to provide monitoring for the workers protection against the ionizing radiations. (N.C.)

  19. Stimuli-responsive smart gating membranes.

    Science.gov (United States)

    Liu, Zhuang; Wang, Wei; Xie, Rui; Ju, Xiao-Jie; Chu, Liang-Yin

    2016-02-07

    Membranes are playing paramount roles in the sustainable development of myriad fields such as energy, environmental and resource management, and human health. However, the unalterable pore size and surface properties of traditional porous membranes restrict their efficient applications. The performances of traditional membranes will be weakened upon unavoidable membrane fouling, and they cannot be applied to cases where self-regulated permeability and selectivity are required. Inspired by natural cell membranes with stimuli-responsive channels, artificial stimuli-responsive smart gating membranes are developed by chemically/physically incorporating stimuli-responsive materials as functional gates into traditional porous membranes, to provide advanced functions and enhanced performances for breaking the bottlenecks of traditional membrane technologies. Smart gating membranes, integrating the advantages of traditional porous membrane substrates and smart functional gates, can self-regulate their permeability and selectivity via the flexible adjustment of pore sizes and surface properties based on the "open/close" switch of the smart gates in response to environmental stimuli. This tutorial review summarizes the recent developments in stimuli-responsive smart gating membranes, including the design strategies and the fabrication strategies that are based on the introduction of the stimuli-responsive gates after or during membrane formation, and the positively and negatively responsive gating models of versatile stimuli-responsive smart gating membranes, as well as the advanced applications of smart gating membranes for regulating substance concentration in reactors, controlling the release rate of drugs, separating active molecules based on size or affinity, and the self-cleaning of membrane surfaces. With self-regulated membrane performances, smart gating membranes show great power for use in global sustainable development.

  20. Glare suppression by coherence gated negation

    CERN Document Server

    Zhou, Edward Haojiang; Brake, Joshua; Ruan, Haowen; Yang, Changhuei

    2016-01-01

    Imaging of a weak target hidden behind a scattering medium can be significantly confounded by glare. We report a method, termed coherence gated negation (CGN), that uses destructive optical interference to suppress glare and allow improved imaging of a weak target. As a demonstration, we show that by permuting through a set range of amplitude and phase values for a reference beam interfering with the optical field from the glare and target reflection, we can suppress glare by an order of magnitude, even when the optical wavefront is highly disordered. This strategy significantly departs from conventional coherence gating methods in that CGN actively 'gates out' the unwanted optical contributions while conventional methods 'gate in' the target optical signal. We further show that the CGN method can outperform conventional coherence gating image quality in certain scenarios by more effectively rejecting unwanted optical contributions.

  1. Method for reworkable packaging of high speed, low electrical parasitic power electronics modules through gate drive integration

    Science.gov (United States)

    Passmore, Brandon; Cole, Zach; Whitaker, Bret; Barkley, Adam; McNutt, Ty; Lostetter, Alexander

    2016-08-02

    A multichip power module directly connecting the busboard to a printed-circuit board that is attached to the power substrate enabling extremely low loop inductance for extreme environments such as high temperature operation. Wire bond interconnections are taught from the power die directly to the busboard further enabling enable low parasitic interconnections. Integration of on-board high frequency bus capacitors provide extremely low loop inductance. An extreme environment gate driver board allows close physical proximity of gate driver and power stage to reduce overall volume and reduce impedance in the control circuit. Parallel spring-loaded pin gate driver PCB connections allows a reliable and reworkable power module to gate driver interconnections.

  2. Gate-induced transition between metal-type and thermally activated transport in self-catalyzed MBE-grown InAs nanowires.

    Science.gov (United States)

    Blömers, C; Rieger, T; Grap, T; Raux, M; Lepsa, M I; Lüth, H; Grützmacher, D; Schäpers, Th

    2013-08-16

    Electronic transport properties of InAs nanowires are studied systematically. The nanowires are grown by molecular beam epitaxy on a SiOx-covered GaAs wafer, without using foreign catalyst particles. Room-temperature measurements revealed relatively high resistivity and low carrier concentration values, which correlate with the low background doping obtained by our growth method. Transport parameters, such as resistivity, mobility, and carrier concentration, show a relatively large spread that is attributed to variations in surface conditions. For some nanowires the conductivity has a metal-type dependence on temperature, i.e. decreasing with decreasing temperature, while other nanowires show the opposite temperature behavior, i.e. temperature-activated characteristics. An applied gate voltage in a field-effect transistor configuration can switch between the two types of behavior. The effect is explained by the presence of barriers formed by potential fluctuations.

  3. Epidermal growth factor upregulates motility of Mat-LyLu rat prostate cancer cells partially via voltage-gated Na+ channel activity

    Science.gov (United States)

    Ding, Yanning; Brackenbury, William J.; Onganer, Pinar U.; Montano, Ximena; Porter, Louise M.; Bates, Lucy F.; Djamgoz, Mustafa B. A.

    2014-01-01

    The main aim of this investigation was to determine whether a functional relationship existed between epidermal growth factor (EGF) and voltage-gated sodium channel (VGSC) upregulation, both associated with strongly metastatic prostate cancer cells. Incubation with EGF for 24 h more than doubled VGSC current density. Similar treatment with EGF significantly and dose-dependently enhanced the cells’ migration through Transwell filters. Both the patch clamp recordings and the migration assay suggested that endogenous EGF played a similar role. Importantly, co-application of EGF and tetrodotoxin, a highly selective VGSC blocker, abolished 65% of the potentiating effect of EGF. It is suggested that a significant portion of the EGF-induced enhancement of migration occurred via VGSC activity. PMID:17960590

  4. Coassembly of big conductance Ca2+-activated K+ channels and L-type voltage-gated Ca2+ channels in rat brain

    DEFF Research Database (Denmark)

    Grunnet, Morten; Kaufmann, Walter A

    2004-01-01

    . The nature of the apparent coupling is not known. In the present study we report a direct coassembly of big conductance Ca(2+)-activated K(+) channels (BK) and L-type voltage-gated Ca(2+) channels in rat brain. Saturation immunoprecipitation studies were performed on membranes labeled for BK channels...... to separate ion channel complexes. Finally, immunochemical studies showed a distinct but overlapping expression pattern of the two types of ion channels investigated. BK and L-type Ca(2+) channels were colocalized in various compartments throughout the rat brain. Taken together, these results demonstrate...... a direct coassembly of BK channels and L-type Ca(2+) channels in certain areas of the brain....

  5. Synergistic antiarrhythmic effect of combining inhibition of Ca(2+)-activated K(+) (SK) channels and voltage-gated Na(+) channels in an isolated heart model of atrial fibrillation

    DEFF Research Database (Denmark)

    Kirchhoff, Jeppe Egedal; Goldin Diness, Jonas; Sheykhzade, Majid

    2015-01-01

    be subefficacious as monotherapy, may prevent atrial fibrillation (AF) and have reduced proarrhythmic potential in the ventricles. METHODS: Subefficacious concentrations of ranolazine, flecainide, and lidocaine were tested alone or in combination with the SK channel blocker N-(pyridin-2-yl)-4-(pyridin-2-yl...... of the adverse effect profile could be an additional advantage if compound concentrations could be reduced. OBJECTIVE: The purpose of this study was to test the hypothesis that combined inhibition of Ca(2+)-activated K(+) channels (SK channels) and voltage-gated Na(+) channels, in concentrations that would......)thiazol-2-amine (ICA) in a Langendorff-perfused guinea pig heart model in which AF was induced after acetylcholine application and burst pacing. RESULTS: AF duration was reduced when both flecainide and ranolazine were combined with ICA in doses that did not reduce AF as monotherapy. At higher...

  6. National Driver Register (NDR) -

    Data.gov (United States)

    Department of Transportation — Information regarding individuals who have had their driver licenses revoked, suspended or otherwise denied for cause, or who have been convicted of certain traffic...

  7. Hysteresis in voltage-gated channels.

    Science.gov (United States)

    Villalba-Galea, Carlos A

    2016-09-30

    Ion channels constitute a superfamily of membrane proteins found in all living creatures. Their activity allows fast translocation of ions across the plasma membrane down the ion's transmembrane electrochemical gradient, resulting in a difference in electrical potential across the plasma membrane, known as the membrane potential. A group within this superfamily, namely voltage-gated channels, displays activity that is sensitive to the membrane potential. The activity of voltage-gated channels is controlled by the membrane potential, while the membrane potential is changed by these channels' activity. This interplay produces variations in the membrane potential that have evolved into electrical signals in many organisms. These signals are essential for numerous biological processes, including neuronal activity, insulin release, muscle contraction, fertilization and many others. In recent years, the activity of the voltage-gated channels has been observed not to follow a simple relationship with the membrane potential. Instead, it has been shown that the activity of voltage-gated channel displays hysteresis. In fact, a growing number of evidence have demonstrated that the voltage dependence of channel activity is dynamically modulated by activity itself. In spite of the great impact that this property can have on electrical signaling, hysteresis in voltage-gated channels is often overlooked. Addressing this issue, this review provides examples of voltage-gated ion channels displaying hysteretic behavior. Further, this review will discuss how Dynamic Voltage Dependence in voltage-gated channels can have a physiological role in electrical signaling. Furthermore, this review will elaborate on the current thoughts on the mechanism underlying hysteresis in voltage-gated channels.

  8. Laser dazzling impacts on car driver performance

    Science.gov (United States)

    Steinvall, Ove; Sandberg, Stig; Hörberg, Ulf; Persson, Rolf; Berglund, Folke; Karslsson, Kjell; Öhgren, Johan; Yu, Zhaohua; Söderberg, Per

    2013-10-01

    A growing problem for the Police and Security Forces has been to prevent potentially hostile individuals to pass a checkpoint, without using lethatl violence. Therefore the question has been if there is a laser or any other strong light source that could be used as a warning and dazzling device, without lethal or long term effects. To investigate the possibilities a field trial has been performed at a motor-racing track. A green CW laser with an irradiance on the eye of maximum 0.5 MPE, as defined by ICNIRP [1] and the ANZI standard [2], was used as a dazzle source. Ten drivers have been driving with dipped headlights through a course of three lines with orange cones. In every line there has been only one gate wide enough to pass without hitting the cones. The time through the course, the choice of gates and the number of cones hit have been measured. For every second trial drive through the track, the driver was exposed to the laser dazzler. The background illuminances ranged from a thousand lux in daylight to about ten millilux in darkness. The protective effect of the sun-visor of the car was investigated. The drives visual system was carefully examined before and after experimental driving and a few weeks after the experimental driving to verify that no pathological effects, that could potentially be induced by the laser exposure, pre-existed or occurred after the laser exposure. An analysis of variance for a within subjects design has been used for evaluation. It was found that green laser light can have an obvious warning effect in daylight. Dazzling does reduce the drivers ability to make judgments and manouver the car in twilight and darkness. A sun-visor can reduce the glare and give the driver an improved control, but that perception can be unjustified. No damage to the visual system was observed.

  9. AKAP150 participates in calcineurin/NFAT activation during the down-regulation of voltage-gated K(+) currents in ventricular myocytes following myocardial infarction.

    Science.gov (United States)

    Nieves-Cintrón, Madeline; Hirenallur-Shanthappa, Dinesh; Nygren, Patrick J; Hinke, Simon A; Dell'Acqua, Mark L; Langeberg, Lorene K; Navedo, Manuel; Santana, Luis F; Scott, John D

    2016-07-01

    The Ca(2+)-responsive phosphatase calcineurin/protein phosphatase 2B dephosphorylates the transcription factor NFATc3. In the myocardium activation of NFATc3 down-regulates the expression of voltage-gated K(+) (Kv) channels after myocardial infarction (MI). This prolongs action potential duration and increases the probability of arrhythmias. Although recent studies infer that calcineurin is activated by local and transient Ca(2+) signals the molecular mechanism that underlies the process is unclear in ventricular myocytes. Here we test the hypothesis that sequestering of calcineurin to the sarcolemma of ventricular myocytes by the anchoring protein AKAP150 is required for acute activation of NFATc3 and the concomitant down-regulation of Kv channels following MI. Biochemical and cell based measurements resolve that approximately 0.2% of the total calcineurin activity in cardiomyocytes is associated with AKAP150. Electrophysiological analyses establish that formation of this AKAP150-calcineurin signaling dyad is essential for the activation of the phosphatase and the subsequent down-regulation of Kv channel currents following MI. Thus AKAP150-mediated targeting of calcineurin to sarcolemmal micro-domains in ventricular myocytes contributes to the local and acute gene remodeling events that lead to the down-regulation of Kv currents.

  10. Young novice drivers.

    NARCIS (Netherlands)

    2013-01-01

    In The Netherlands, young novice drivers (18-24 years of age) show a crash rate that is five times higher than that of experienced drivers (30-59 years of age). The rate of young males is even seven times as high. The main reasons are lack of driving experience and hazardous behaviour typical of ado

  11. A Simple Wave Driver

    Science.gov (United States)

    Temiz, Burak Kagan; Yavuz, Ahmet

    2015-01-01

    This study was done to develop a simple and inexpensive wave driver that can be used in experiments on string waves. The wave driver was made using a battery-operated toy car, and the apparatus can be used to produce string waves at a fixed frequency. The working principle of the apparatus is as follows: shortly after the car is turned on, the…

  12. The Inhibitory Effects of Ketamine on Human Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels and Action Potential in Rabbit Sinoatrial Node.

    Science.gov (United States)

    Xing, Junlian; Zhang, Chi; Jiang, Wanzhen; Hao, Jie; Liu, Zhipei; Luo, Antao; Zhang, Peihua; Fan, Xinrong; Ma, Jihua

    2017-01-01

    To investigate the effects of ketamine on human hyperpolarization-activated cyclic nucleotide-gated (hHCN) 1, 2, 4 channel currents expressed in Xenopus oocytes and spontaneous action potentials (APs) of rabbit sinoatrial node (SAN). The 2-electrode voltage clamp and standard microelectrode techniques were respectively applied to record hHCN channels currents expressed in Xenopus oocytes and APs of SAN separated from rabbit heart. Ketamine (1-625 µmol/L) blocked hHCN1, 2, and 4 currents with IC50 of 67.0, 89.1, and 84.0 µmol/L, respectively, in a concentration-dependent manner. The currents were rapidly blocked by ketamine and partially recovered after washout. The steady-state activation curves of hHCN1, 2, and 4 currents demonstrated a concentration-dependent shift to the left and the rates of activation were significantly decelerated. But ketamine blocked hHCN channels in a voltage-independence and non-use-dependent manner, and did not modify the voltage dependence of activation and reversal potentials. Furthermore, ketamine suppressed phase-4 spontaneous depolarization rate in isolated rabbit SAN and decreased the beat rates in a concentration-dependent manner. Ketamine could inhibit hHCN channels expressed in Xenopus oocytes in a concentration-dependent manner as a close-state blocker and decrease beat rates of isolated rabbit SAN. This study may provide novel insights into other unexplained actions of ketamine. © 2017 S. Karger AG, Basel.

  13. Activation of CRH receptor type 1 expressed on glutamatergic neurons increases excitability of CA1 pyramidal neurons by the modulation of voltage-gated ion channels

    Directory of Open Access Journals (Sweden)

    Stephan eKratzer

    2013-07-01

    Full Text Available Corticotropin-releasing hormone (CRH plays an important role in a substantial number of patients with stress-related mental disorders, such as anxiety disorders and depression. CRH has been shown to increase neuronal excitability in the hippocampus, but the underlying mechanisms are poorly understood. The effects of CRH on neuronal excitability were investigated in acute hippocampal brain slices. Population spikes (PS and field excitatory postsynaptic potentials (fEPSP were evoked by stimulating Schaffer-collaterals and recorded simultaneously from the somatic and dendritic region of CA1 pyramidal neurons. CRH was found to increase PS amplitudes (mean  Standard error of the mean; 231.8  31.2% of control; n=10 while neither affecting fEPSPs (104.3 ± 4.2%; n=10 nor long-term potentiation (LTP. However, when Schaffer-collaterals were excited via action potentials (APs generated by stimulation of CA3 pyramidal neurons, CRH increased fEPSP amplitudes (119.8 ± 3.6%; n=8 and the magnitude of LTP in the CA1 region. Experiments in slices from transgenic mice revealed that the effect on PS amplitude is mediated exclusively by CRH receptor 1 (CRHR1 expressed on glutamatergic neurons. The effects of CRH on PS were dependent on phosphatase-2B, L- and T-type calcium channels and voltage-gated potassium channels but independent on intracellular Ca2+-elevation. In patch-clamp experiments, CRH increased the frequency and decay times of APs and decreased currents through A-type and delayed-rectifier potassium channels. These results suggest that CRH does not affect synaptic transmission per se, but modulates voltage-gated ion currents important for the generation of APs and hence elevates by this route overall neuronal activity.

  14. The gating of the CFTR channel.

    Science.gov (United States)

    Moran, Oscar

    2017-01-01

    Cystic fibrosis transmembrane conductance regulator (CFTR) is an anion channel expressed in the apical membrane of epithelia. Mutations in the CFTR gene are the cause of cystsic fibrosis. CFTR is the only ABC-protein that constitutes an ion channel pore forming subunit. CFTR gating is regulated in complex manner as phosphorylation is mandatory for channel activity and gating is directly regulated by binding of ATP to specific intracellular sites on the CFTR protein. This review covers our current understanding on the gating mechanism in CFTR and illustrates the relevance of alteration of these mechanisms in the onset of cystic fibrosis.

  15. Meet me on the other side: trans-bilayer modulation of a model voltage-gated ion channel activity by membrane electrostatics asymmetry.

    Directory of Open Access Journals (Sweden)

    Loredana Mereuta

    Full Text Available While it is accepted that biomembrane asymmetry is generated by proteins and phospholipids distribution, little is known about how electric changes manifested in a monolayer influence functional properties of proteins localized on the opposite leaflet. Herein we used single-molecule electrophysiology and investigated how asymmetric changes in the electrostatics of an artificial lipid membrane monolayer, generated oppositely from where alamethicin--a model voltage-gated ion channel--was added, altered peptide activity. We found that phlorizin, a membrane dipole potential lowering amphiphile, augmented alamethicin activity and transport features, whereas the opposite occurred with RH-421, which enhances the monolayer dipole potential. Further, the monolayer surface potential was decreased via adsorption of sodium dodecyl sulfate, and demonstrated that vectorial modification of it also affected the alamethicin activity in a predictive manner. A new paradigm is suggested according to which asymmetric changes in the monolayer dipole and surface potential extend their effects spatially by altering the intramembrane potential, whose gradient is sensed by distantly located peptides.

  16. Mice repeatedly exposed to Group-A β-Haemolytic Streptococcus show perseverative behaviors, impaired sensorimotor gating, and immune activation in rostral diencephalon.

    Science.gov (United States)

    Macrì, Simone; Ceci, Chiara; Onori, Martina Proietti; Invernizzi, Roberto William; Bartolini, Erika; Altabella, Luisa; Canese, Rossella; Imperi, Monica; Orefici, Graziella; Creti, Roberta; Margarit, Immaculada; Magliozzi, Roberta; Laviola, Giovanni

    2015-08-25

    Repeated exposure to Group-A β-Haemolytic Streptococcus (GAS) may constitute a vulnerability factor in the onset and course of pediatric motor disturbances. GAS infections/colonization can stimulate the production of antibodies, which may cross the blood brain barrier, target selected brain areas (e.g. basal ganglia), and exacerbate motor alterations. Here, we exposed developing SJL male mice to four injections with a GAS homogenate and evaluated the following domains: motor coordination; general locomotion; repetitive behaviors; perseverative responses; and sensorimotor gating (pre-pulse inhibition, PPI). To demonstrate that behavioral changes were associated with immune-mediated brain alterations, we analyzed, in selected brain areas, the presence of infiltrates and microglial activation (immunohistochemistry), monoamines (HPLC), and brain metabolites (in vivo Magnetic Resonance Spectroscopy). GAS-exposed mice showed increased repetitive and perseverative behaviors, impaired PPI, and reduced concentrations of serotonin in prefrontal cortex, a brain area linked to the behavioral domains investigated, wherein they also showed remarkable elevations in lactate. Active inflammatory processes were substantiated by the observation of infiltrates and microglial activation in the white matter of the anterior diencephalon. These data support the hypothesis that repeated GAS exposure may elicit inflammatory responses in brain areas involved in motor control and perseverative behavior, and result in phenotypic abnormalities.

  17. Genetic Correction of SOD1 Mutant iPSCs Reveals ERK and JNK Activated AP1 as a Driver of Neurodegeneration in Amyotrophic Lateral Sclerosis

    Directory of Open Access Journals (Sweden)

    Akshay Bhinge

    2017-04-01

    Full Text Available Although mutations in several genes with diverse functions have been known to cause amyotrophic lateral sclerosis (ALS, it is unknown to what extent causal mutations impinge on common pathways that drive motor neuron (MN-specific neurodegeneration. In this study, we combined induced pluripotent stem cells-based disease modeling with genome engineering and deep RNA sequencing to identify pathways dysregulated by mutant SOD1 in human MNs. Gene expression profiling and pathway analysis followed by pharmacological screening identified activated ERK and JNK signaling as key drivers of neurodegeneration in mutant SOD1 MNs. The AP1 complex member JUN, an ERK/JNK downstream target, was observed to be highly expressed in MNs compared with non-MNs, providing a mechanistic insight into the specific degeneration of MNs. Importantly, investigations of mutant FUS MNs identified activated p38 and ERK, indicating that network perturbations induced by ALS-causing mutations converge partly on a few specific pathways that are drug responsive and provide immense therapeutic potential.

  18. Human activities as a driver of spatial variation in the trophic structure of fish communities on Pacific coral reefs.

    Science.gov (United States)

    Ruppert, Jonathan L W; Vigliola, Laurent; Kulbicki, Michel; Labrosse, Pierre; Fortin, Marie-Josée; Meekan, Mark G

    2017-09-25

    Anthropogenic activities such as land-use change, pollution and fishing impact the trophic structure of coral reef fishes, which can influence ecosystem health and function. Although these impacts may be ubiquitous, they are not consistent across the tropical Pacific Ocean. Using an extensive database of fish biomass sampled using underwater visual transects on coral reefs, we modelled the impact of human activities on food webs at Pacific-wide and regional (1,000s-10,000s km) scales. We found significantly lower biomass of sharks and carnivores, where there were higher densities of human populations (hereafter referred to as human activity); however, these patterns were not spatially consistent as there were significant differences in the trophic structures of fishes among biogeographic regions. Additionally, we found significant changes in the benthic structure of reef environments, notably a decline in coral cover where there was more human activity. Direct human impacts were the strongest in the upper part of the food web, where we found that in a majority of the Pacific, the biomass of reef sharks and carnivores were significantly and negatively associated with human activity. Finally, although human-induced stressors varied in strength and significance throughout the coral reef food web across the Pacific, socioeconomic variables explained more variation in reef fish trophic structure than habitat variables in a majority of the biogeographic regions. Notably, economic development (measured as GDP per capita) did not guarantee healthy reef ecosystems (high coral cover and greater fish biomass). Our results indicate that human activities are significantly shaping patterns of trophic structure of reef fishes in a spatially nonuniform manner across the Pacific Ocean, by altering processes that organize communities in both "top-down" (fishing of predators) and "bottom-up" (degradation of benthic communities) contexts. © 2017 John Wiley & Sons Ltd.

  19. Understanding drivers of peatland extracellular enzyme activity in the PEATcosm experiment: mixed evidence for enzymic latch hypothesis

    Science.gov (United States)

    Karl J. Romanowicz; Evan S. Kane; Lynette R. Potvin; Aleta L. Daniels; Randy Kolka; Erik A. Lilleskov

    2015-01-01

    Aims. Our objective was to assess the impacts of water table position and plant functional groups on peatland extracellular enzyme activity (EEA) framed within the context of the enzymic latch hypothesis. Methods. We utilized a full factorial experiment with 2 water table (WT) treatments (high and low) and 3 plant functional...

  20. Merger and Acquisition Activity as Driver of Spatial Clustering : The Spatial Evolution of the Dutch Banking Industry, 1850-1993

    NARCIS (Netherlands)

    Boschma, Ron; Hartog, Matté

    2014-01-01

    This article investigates the extent to which merger and acquisition (M&A) activity contributed to the spatial clustering of the Dutch banking industry in Amsterdam. This analysis is based on a unique database of all banks in the Netherlands that existed in the period 1850-1993. We found that

  1. Merger and Acquisition Activity as Driver of Spatial Clustering : The Spatial Evolution of the Dutch Banking Industry, 1850-1993

    NARCIS (Netherlands)

    Boschma, Ron; Hartog, Matté

    2014-01-01

    This article investigates the extent to which merger and acquisition (M&A) activity contributed to the spatial clustering of the Dutch banking industry in Amsterdam. This analysis is based on a unique database of all banks in the Netherlands that existed in the period 1850-1993. We found that spatia

  2. Graduate Automotive Technology Education (GATE) Center

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey Hodgson; David Irick

    2005-09-30

    The Graduate Automotive Technology Education (GATE) Center at the University of Tennessee, Knoxville has completed its sixth year of operation. During this period the Center has involved thirteen GATE Fellows and ten GATE Research Assistants in preparing them to contribute to advanced automotive technologies in the center's focus area: hybrid drive trains and control systems. Eighteen GATE students have graduated, and three have completed their course work requirements. Nine faculty members from three departments in the College of Engineering have been involved in the GATE Center. In addition to the impact that the Center has had on the students and faculty involved, the presence of the center has led to the acquisition of resources that probably would not have been obtained if the GATE Center had not existed. Significant industry interaction such as internships, equipment donations, and support for GATE students has been realized. The value of the total resources brought to the university (including related research contracts) exceeds $4,000,000. Problem areas are discussed in the hope that future activities may benefit from the operation of the current program.

  3. Climate and root proximity as dominant drivers of enzyme activity and C and N isotopic signature in soil

    Science.gov (United States)

    Stock, Svenja; Köster, Moritz; Dippold, Michaela; Boy, Jens; Matus, Francisco; Merino, Carolina; Nájera, Francisco; Spielvogel, Sandra; Gorbushina, Anna; Kuzyakov, Yakov

    2017-04-01

    The Chilean ecosystems provide a unique study area to investigate biotic controls on soil organic matter (SOM) decomposition and mineral weathering depending on climate (from hyper arid to temperate humid). Microorganisms play a crucial role in the SOM decomposition, nutrient release and cycling. By means of extracellular enzymes microorganisms break down organic compounds and provide nutrients for plants. Soil moisture (abiotic factor) and root carbon (biotic factor providing easily available energy source for microorganisms), are important factors for microbial decomposition of SOM and show strong gradients along the investigated climatic gradient. A high input of root carbon increases microbial activity and enzyme production, and facilitates SOM breakdown and nutrient release The aim of this study was to determine the potential enzymatic SOM decomposition and nutrient release depending on root proximity and precipitation. C and N contents, δ13C and δ15N values, and kinetics (Vmax, Km) of six extracellular enzymes, responsible for C, N, and P cycles, were quantified in vertical (soil depth) and horizontal (from roots to bulk soil) gradients in two climatic regions: within a humid temperate forest and a semiarid open forest. The greater productivity of the temperate forest was reflected by higher C and N contents compared to the semiarid forest. Regression lines between δ13C and -[ln(%C)] showed a stronger isotopic fractionation from top- to subsoil at the semiarid open forest, indicating a faster SOM turnover compared to the humid temperate forest. This is the result of more favorable soil conditions (esp. temperature and smaller C/N ratios) in the semiarid forest. Depth trends of δ15N values indicated N limitation in both soils, though the limitation at the temperate site was stronger. The activity of enzymes degrading cellulose and hemicellulose increased with C content. Activity of enzymes involved in C, N and P cycles decreased from top- to subsoil and

  4. Recent changes in avalanche activity in the French Alps and their links with climatic drivers: an overview

    OpenAIRE

    Eckert, N.; Lavigne, A.; Castebrunet, H.; Giraud, G.; Naaim, M.

    2013-01-01

    International audience; This paper synthetizes our ongoing work on relations between natural avalanche activity and climate change in the French Alps and subregions. Firm results mainly concern occurrences, runout altitudes and high return period avalanches on long time scales (averages over “full” winters and winter-spring sub-seasons) since ~1950. Work in progress concerns extrapolation under future climate, shorter time scales (avalanche cycles), and more generally risk assessment under un...

  5. Drivers 65 Plus

    Science.gov (United States)

    ... see, hear, and feel in relation to other cars and drivers, traffic signs and signals, conditions of the highway, and the performance of your car. These decisions are usually made close to other ...

  6. Proactive driver training program

    Energy Technology Data Exchange (ETDEWEB)

    Vossler, W. [Kinetic Safety Consulting Inc., Grande Prairie, AB (Canada)

    2005-07-01

    Skid avoidance training is a recent approach to driver training and has been employed in various countries with a high degree of success. Among top ranked countries, motor vehicle incidents trends indicate higher incident rates among drivers are often due to lack of knowledge, experience and risk awareness. If lowered age limit experience is attained under direct supervision and in safe training conditions, it was suggested, incident frequency is reduced. A Norway study confirmed an increase in vehicle incident rates after drivers had received skid control training. The drivers were unable to maintain skill levels needed to react to critical driving tasks and had unrealistic expectations of skill after training. However, a skid avoidance training program launched in Sweden in 1999 has resulted in a 50 per cent reduction of vehicle incidents in the last 2 years. Details of the Skidcar System were presented, including details of the driving simulator, where simulation of actual driving situations is achieved by simply adjusting the amount of grip the vehicle has with the driving surface. Instructors modify driving behaviors based upon the driver's ability to maintain grip. There are over 200 units in North America. In addition, a Proactive Light Vehicle Driver Training/ Heavy Vehicle Assessment Program was initiated in 2003, with a motor vehicle incident rate reduction of 50 per cent at the end of 2004. Various examples of situations in which drivers have used their skid avoidance skills to avoid incidents were included. It was noted that the trend among driver training professionals has been towards decision-based rather than skills-based training, as skills-based training will diminish over time, and requires frequent re-training periods. Cognitive and perceptual skills were examined, as well as cognitive, associative and autonomous learning phases. It was concluded that skid avoidance is largely a decision-based skill. tabs, figs.

  7. Activation of voltage-gated KCNQ/Kv7 channels by anticonvulsant retigabine attenuates mechanical allodynia of inflammatory temporomandibular joint in rats

    Directory of Open Access Journals (Sweden)

    Xu Wen

    2010-08-01

    Full Text Available Abstract Background Temporomandibular disorders (TMDs are characterized by persistent orofacial pain and have diverse etiologic factors that are not well understood. It is thought that central sensitization leads to neuronal hyperexcitability and contributes to hyperalgesia and spontaneous pain. Nonsteroidal anti-inflammatory drugs (NSAIDs are currently the first choice of drug to relieve TMD pain. NSAIDS were shown to exhibit anticonvulsant properties and suppress cortical neuron activities by enhancing neuronal voltage-gated potassium KCNQ/Kv7 channels (M-current, suggesting that specific activation of M-current might be beneficial for TMD pain. Results In this study, we selected a new anticonvulsant drug retigabine that specifically activates M-current, and investigated the effect of retigabine on inflammation of the temporomandibular joint (TMJ induced by complete Freund's adjuvant (CFA in rats. The results show that the head withdrawal threshold for escape from mechanical stimulation applied to facial skin over the TMJ in inflamed rats was significantly lower than that in control rats. Administration of centrally acting M-channel opener retigabine (2.5 and 7.5 mg/kg can dose-dependently raise the head withdrawal threshold of mechanical allodynia, and this analgesic effect can be reversed by the specific KCNQ channel blocker XE991 (3 mg/kg. Food intake is known to be negatively associated with TMJ inflammation. Food intake was increased significantly by the administration of retigabine (2.5 and 7.5 mg/kg, and this effect was reversed by XE991 (3 mg/kg. Furthermore, intracerebralventricular injection of retigabine further confirmed the analgesic effect of central retigabine on inflammatory TMJ. Conclusions Our findings indicate that central sensitization is involved in inflammatory TMJ pain and pharmacological intervention for controlling central hyperexcitability by activation of neuronal KCNQ/M-channels may have therapeutic potential for

  8. Older drivers, crashes and injuries.

    Science.gov (United States)

    Koppel, Sjaanie; Bohensky, Megan; Langford, Jim; Taranto, David

    2011-10-01

    This article aimed to identify the main features of older driver casualty crashes, including detailed descriptions of injury outcomes. Data were obtained from the Transport Accident Commission insurance claims database for 2 groups of drivers: aged 41 to 55 years (middle-aged drivers) and aged 65 years and older (older drivers). In terms of crash circumstances, the majority of crashes involved a collision with another vehicle (70.0% of middle-aged drivers and 68.7% of older drivers). The 2 main maneuvers at the time of crash were driving straight ahead (44.6% of middle-aged drivers and 42.8% of older drivers) and turning right (equivalent of left turn in North America; 15.2% of middle-aged drivers and 17.6% of older drivers). In terms of injury outcomes, older drivers sustained a significantly higher proportion of injuries to the thorax (30.9% compared to 18.5% of middle-aged drivers). Conversely, a significantly higher proportion of middle-aged drivers sustained some form of injury to the neck (30.6% compared to 12.1% of older drivers). These findings highlight the situations that are particularly risky for older drivers and provide important insights for developing solutions to reduce older driver crash and injury risk.

  9. Characteristics of Chinese Driver Behavior

    NARCIS (Netherlands)

    Li, J.

    2014-01-01

    The high growth rate of vehicle ownership and many novel drivers in China determine the special features of Chinese driver behavior. This thesis introduces a comparative study on driver behavior by the analysis of saturation flow at urban intersections, Driver Behavior Questionnaire surveys, focus g

  10. Allowable Generalized Quantum Gates

    Institute of Scientific and Technical Information of China (English)

    LONG Gui-Lu; LIU Yang; WANG Chuan

    2009-01-01

    In this paper, we give the most general duality gates, or generalized quantum gates in duality quantum computers. Here we show by explicit construction that a n-bit duality quantum computer with d slits can be simulated perfectly with an ordinary quantum computer with n qubits and one auxiliary qudit. Using this model, we give the most general form of duality gates which is of the form Σ(d-1)(i=0)piUi, and the Pi's are complex numbers with module less or equal to I and constrained by |Σipi|≤1.

  11. The S4-S5 linker directly couples voltage sensor movement to the activation gate in the human ether-a'-go-go-related gene (hERG) K+ channel.

    Science.gov (United States)

    Ferrer, Tania; Rupp, Jason; Piper, David R; Tristani-Firouzi, Martin

    2006-05-05

    A key unresolved question regarding the basic function of voltage-gated ion channels is how movement of the voltage sensor is coupled to channel opening. We previously proposed that the S4-S5 linker couples voltage sensor movement to the S6 domain in the human ether-a'-go-go-related gene (hERG) K+ channel. The recently solved crystal structure of the voltage-gated Kv1.2 channel reveals that the S4-S5 linker is the structural link between the voltage sensing and pore domains. In this study, we used chimeras constructed from hERG and ether-a'-go-go (EAG) channels to identify interactions between residues in the S4-S5 linker and S6 domain that were critical for stabilizing the channel in a closed state. To verify the spatial proximity of these regions, we introduced cysteines in the S4-S5 linker and at the C-terminal end of the S6 domain and then probed for the effect of oxidation. The D540C-L666C channel current decreased in an oxidizing environment in a state-dependent manner consistent with formation of a disulfide bond that locked the channel in a closed state. Disulfide bond formation also restricted movement of the voltage sensor, as measured by gating currents. Taken together, these data confirm that the S4-S5 linker directly couples voltage sensor movement to the activation gate. Moreover, rather than functioning simply as a mechanical lever, these findings imply that specific interactions between the S4-S5 linker and the activation gate stabilize the closed channel conformation.

  12. Mechanical gating of a mechanochemical reaction cascade

    Science.gov (United States)

    Wang, Junpeng; Kouznetsova, Tatiana B.; Boulatov, Roman; Craig, Stephen L.

    2016-11-01

    Covalent polymer mechanochemistry offers promising opportunities for the control and engineering of reactivity. To date, covalent mechanochemistry has largely been limited to individual reactions, but it also presents potential for intricate reaction systems and feedback loops. Here we report a molecular architecture, in which a cyclobutane mechanophore functions as a gate to regulate the activation of a second mechanophore, dichlorocyclopropane, resulting in a mechanochemical cascade reaction. Single-molecule force spectroscopy, pulsed ultrasonication experiments and DFT-level calculations support gating and indicate that extra force of >0.5 nN needs to be applied to a polymer of gated gDCC than of free gDCC for the mechanochemical isomerization gDCC to proceed at equal rate. The gating concept provides a mechanism by which to regulate stress-responsive behaviours, such as load-strengthening and mechanochromism, in future materials designs.

  13. Spa13 of Shigella flexneri has a dual role: chaperone escort and export gate-activator switch of the type III secretion system.

    Science.gov (United States)

    Cherradi, Youness; Hachani, Abderrahman; Allaoui, Abdelmounaaïm

    2014-01-01

    The type III secretion apparatus (T3SA) is used by numerous Gram-negative pathogens to inject virulence factors into eukaryotic cells. The Shigella flexneri T3SA spans the bacterial envelope and its assembly requires the products of ~20 mxi and spa genes. Despite progress made in understanding how the T3SA is assembled, the role of several predicted soluble components, such as Spa13, remains elusive. Here, we show that the secretion defect of the spa13 mutant is associated with lack of T3SA assembly which is partly due to the instability of the needle component MxiH. In contrast to its Yersinia counterpart, Spa13 is not a secreted protein. We identified a network of interactions between Spa13 and the ATPase Spa47, the C-ring protein Spa33, and the inner-membrane protein Spa40. Moreover, we revealed a Spa13 interaction with the inner-membrane MxiA and showed that overexpression of the large cytoplasmic domain of MxiA in the WT background shuts off secretion. Lastly, we demonstrated that Spa13 interacts with the cleaved form of Spa40 and with the translocator chaperone IpgC, suggesting that Spa13 intervenes during the secretion hierarchy switch process. Collectively, our results support a dual role of Spa13 as a chaperone escort and as an export gate-activator switch.

  14. Integrated 3D control concept for active driver assistance; Integriertes drei-dimensionales Fuehrungskonzept als aktive Fahrerassistenz

    Energy Technology Data Exchange (ETDEWEB)

    Greul, R.; Bertram, T. [Univ. Duisburg (Germany); Seemann, M.

    2002-07-01

    The integration of by-wire systems into motor vehicles offers great potential for improvement in active and passive safety. Assistance systems that improve safety can be simply adapted through the application in electronics of safety relevant vehicle functions. Another aspect is the possibility of networking individual electronic components and to improve performance in comparison to original individual systems through the coordination of the modules. This method is used in the research presented here to develop an integrated control concept. Modules for vehicle condition recognition and autonomous vehicle dynamics control were also developed. Autonomous control is applied in the areas of steering, braking and damping. As components of the electronic network, the modules are overseen by a supervisory unit - the integrations controller. Simulation results and the application of individual components and their integration based on this description of the modules required and their application is also presented here. (orig.) [German] Der Einzug von By-wire Systemen in das Kraftfahrzeug verspricht ein grosses Potenzial fuer die Erhoehung der aktiven und passiven Sicherheit. Durch die elektronische Umsetzung von sicherheitsrelevanten Fahrzeugfunktionen koennen sicherheitssteigernde Assistenzsysteme einfach adaptiert werden. Ein anderer Aspekt ist die Moeglichkeit einzelne Elektronikkomponenten zu vernetzen und durch die Koordination der Module eine Leistungsverbesserung gegenueber der Einzelkomponente zu erreichen. Dieser Umstand wird genutzt, um im Rahmen des Beitrages eine Integrationsregelung vorzustellen. Dabei werden Module fuer die Bereiche Fahrzustandsbeurteilung und autonome Fahrdynamikregelung entwickelt. Autonome Regelungen kommen in den Bereichen Lenken, Bremsen und Daempfen zur Anwendung. Als Komponenten des elektronischen Netzwerkes werden diese Module durch eine uebergeordnete Instanz ueberwacht, dem Modul der Integrationsregelung. Ausgehend von einer

  15. A 10 kW dc-dc converter using IGBTs with active snubbers. [Insulated Gate Bipolar Transistor

    Science.gov (United States)

    Masserant, Brian J.; Shriver, Jeffrey L.; Stuart, Thomas A.

    1993-01-01

    This full bridge dc-dc converter employs zero voltage switching (ZVS) on one leg and zero current switching (ZCS) on the other. This technique produces exceptionally low IGBT switching losses through the use of an active snubber that recycles energy back to the source. Experimental results are presented for a 10 kW, 20 kHz converter.

  16. Characteristics of Chinese Driver Behavior

    OpenAIRE

    LI J

    2014-01-01

    The high growth rate of vehicle ownership and many novel drivers in China determine the special features of Chinese driver behavior. This thesis introduces a comparative study on driver behavior by the analysis of saturation flow at urban intersections, Driver Behavior Questionnaire surveys, focus group discussion, and in-car tests. The main characteristics of Chinese driver behavior have been identified. A new method is developed for a simulation model calibration based on the study results.

  17. Le temps des conductrices de bus The time of female bus drivers. For some thinking space between professional and personal activities

    Directory of Open Access Journals (Sweden)

    Livia Scheller

    2009-11-01

    Full Text Available Nous présentons une réflexion sur les liens entre temps de travail et temps de l’espace privé, issue d’une étude faite avec des conductrices de bus.  Pour elles, comme pour la plupart des femmes, le temps de travail et le temps dit « hors travail » sont difficilement dissociables. Si la séparation entre sphères d’activité est, pour les hommes et pour les femmes, une dimension psychiquement recherchée, chez les femmes elle n’implique pas des clivages constitutifs. Elles savent bien que l’activité de travail offre des occasions de développement d’une autre origine que celles déployées dans d’autres espaces de vie. Mais à la différence des hommes, elles n’ont pas fait de cette séparation un repère identitaire. Nous avançons que la capacité de différencier, d’une part, ces genres d’activité, et, d’autre part, la possibilité de les investir « normativement », peut être une source de santé. Comment ? En créant les modes de séparation nécessaires à cette différenciation, sans pour autant perdre la perméabilité entre les deux espaces. Il s’agit de penser une position qui, bien qu’apparemment contradictoire, ne l’est pas. On pourra en trouver une illustration dans l’expérience des conductrices de bus.Taking off from a study we carried out with woman bus drivers, we analyze how working time and private time relate to each other. For them, as for most women, time at work and time off work cannot be completely separated. While psychologically the separation between different spheres of activity is something to which both men and women aspire, women do not actually demand it. They seem to know that the possibilities afforded by work are of a different nature than those of other sorts of activity. However, unlike men, women have not made that distinction a point of reference in their self-identity. We argue that the ability to distinguish the types of activity on the one hand, and on the

  18. Slide Gate Bricks

    Institute of Scientific and Technical Information of China (English)

    Wang Jing; Peng Xigao

    2010-01-01

    @@ 1 Scope This standard specifies the classification,shape,dimension,technical requirements,test methods,quality appraisal procedures,packing,marking,transportation,storage,and quality certificate of slide gate bricks.

  19. Engineering Customized TALENs Using the Platinum Gate TALEN Kit.

    Science.gov (United States)

    Sakuma, Tetsushi; Yamamoto, Takashi

    2016-01-01

    Among various strategies for constructing customized transcription activator-like effector nucleases (TALENs), the Golden Gate assembly is the most widely used and most characterized method. The principle of Golden Gate assembly involves cycling reactions of digestion and ligation of multiple plasmids in a single tube, resulting in PCR-, fragmentation-, and purification-free concatemerization of DNA-binding repeats. Here, we describe the protocols for Golden Gate assembly-based TALEN construction using the Platinum Gate TALEN Kit, which allows generation of highly active Platinum TALENs.

  20. Advanced insulated gate bipolar transistor gate drive

    Science.gov (United States)

    Short, James Evans; West, Shawn Michael; Fabean, Robert J.

    2009-08-04

    A gate drive for an insulated gate bipolar transistor (IGBT) includes a control and protection module coupled to a collector terminal of the IGBT, an optical communications module coupled to the control and protection module, a power supply module coupled to the control and protection module and an output power stage module with inputs coupled to the power supply module and the control and protection module, and outputs coupled to a gate terminal and an emitter terminal of the IGBT. The optical communications module is configured to send control signals to the control and protection module. The power supply module is configured to distribute inputted power to the control and protection module. The control and protection module outputs on/off, soft turn-off and/or soft turn-on signals to the output power stage module, which, in turn, supplies a current based on the signal(s) from the control and protection module for charging or discharging an input capacitance of the IGBT.

  1. Neurotoxic activity of venom from the Australian Eastern mouse spider (Missulena bradleyi) involves modulation of sodium channel gating

    OpenAIRE

    Rash, Lachlan D; Birinyi-Strachan, Liesl C; Nicholson, Graham M.; Wayne C. Hodgson

    2000-01-01

    Mouse spiders represent a potential cause of serious envenomation in humans. This study examined the activity of Missulena bradleyi venom in several in vitro preparations. Whilst female M. bradleyi venom at doses up to 0.05 μl ml−1 failed to alter twitch or resting tension in all preparations used, male venom (0.02 and 0.05 μl ml−1) produced potent effects on transmitter release in both smooth and skeletal neuromuscular preparations.In the mouse phrenic nerve diaphragm preparation, male M. br...

  2. Voltage-gated Proton Channels

    Science.gov (United States)

    DeCoursey, Thomas E.

    2014-01-01

    Voltage-gated proton channels, HV1, have vaulted from the realm of the esoteric into the forefront of a central question facing ion channel biophysicists, namely the mechanism by which voltage-dependent gating occurs. This transformation is the result of several factors. Identification of the gene in 2006 revealed that proton channels are homologues of the voltage-sensing domain of most other voltage-gated ion channels. Unique, or at least eccentric, properties of proton channels include dimeric architecture with dual conduction pathways, perfect proton selectivity, a single-channel conductance ~103 smaller than most ion channels, voltage-dependent gating that is strongly modulated by the pH gradient, ΔpH, and potent inhibition by Zn2+ (in many species) but an absence of other potent inhibitors. The recent identification of HV1 in three unicellular marine plankton species has dramatically expanded the phylogenetic family tree. Interest in proton channels in their own right has increased as important physiological roles have been identified in many cells. Proton channels trigger the bioluminescent flash of dinoflagellates, facilitate calcification by coccolithophores, regulate pH-dependent processes in eggs and sperm during fertilization, secrete acid to control the pH of airway fluids, facilitate histamine secretion by basophils, and play a signaling role in facilitating B-cell receptor mediated responses in B lymphocytes. The most elaborate and best-established functions occur in phagocytes, where proton channels optimize the activity of NADPH oxidase, an important producer of reactive oxygen species. Proton efflux mediated by HV1 balances the charge translocated across the membrane by electrons through NADPH oxidase, minimizes changes in cytoplasmic and phagosomal pH, limits osmotic swelling of the phagosome, and provides substrate H+ for the production of H2O2 and HOCl, reactive oxygen species crucial to killing pathogens. PMID:23798303

  3. High-Confidence Quantum Gate Tomography

    Science.gov (United States)

    Johnson, Blake; da Silva, Marcus; Ryan, Colm; Kimmel, Shelby; Donovan, Brian; Ohki, Thomas

    2014-03-01

    Debugging and verification of high-fidelity quantum gates requires the development of new tools and protocols to unwrap the performance of the gate from the rest of the sequence. Randomized benchmarking tomography[2] allows one to extract full information of the unital portion of the gate with high confidence. We report experimental confirmation of the technique's applicability to quantum gate tomography. We show that the method is robust to common experimental imperfections such as imperfect single-shot readout and state preparation. We also demonstrate the ability to characterize non-Clifford gates. To assist in the experimental implementation we introduce two techniques. ``Atomic Cliffords'' use phase ramping and frame tracking to allow single-pulse implementation of the full group of single-qubit Clifford gates. Domain specific pulse sequencers allow rapid implementation of the many thousands of sequences needed. This research was funded by the Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA), through the Army Research Office contract no. W911NF-10-1-0324.

  4. Alternate laser fusion drivers

    Energy Technology Data Exchange (ETDEWEB)

    Pleasance, L.D.

    1979-11-01

    Over the past few years, several laser systems have been considered as possible laser fusion drivers. Recently, there has been an increasing effort to evaluate these systems in terms of a reactor driver application. The specifications for such a system have become firmer and generally more restrictive. Several of the promising candidates such as the group VI laser, the metal vapor excimers and some solid state lasers can be eliminated on the basis of inefficiency. New solid state systems may impact the long range development of a fusion driver. Of the short wavelength gas lasers, the KrF laser used in conjunction with Raman compression and pulse stacking techniques is the most promising approach. Efficiencies approaching 10% may be possible with this system. While technically feasible, these approaches are complex and costly and are unsatisfying in an aethetic sense. A search for new lasers with more compelling features is still needed.

  5. Really Scary Drivers

    Institute of Scientific and Technical Information of China (English)

    马莲花

    2005-01-01

    A new wave of "road killers", or new drivers, on Beijing's streets has prompted traffic authorities to do something to make driving tests more difficult. This year, the move has targeted new drivers to keep them from posing a threat, the Beijing Traffic Management Bureau says. The new test has been adopted citywide and the average pass rate is down to 50 per cent from a previous 80 per cent, at the city's 22 test centers, said Jiang Jing, a bureau press officer. The test now has six mandatory items chosen r...

  6. Coordinated role of voltage-gated sodium channels and the Na{sup +}/H{sup +} exchanger in sustaining microglial activation during inflammation

    Energy Technology Data Exchange (ETDEWEB)

    Hossain, Muhammad M. [Department of Environmental and Occupational Medicine and Environmental and Occupational Health Sciences Institute, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ (United States); Sonsalla, Patricia K. [Department of Neurology, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ (United States); Richardson, Jason R., E-mail: jricha3@eohsi.rutgers.edu [Department of Environmental and Occupational Medicine and Environmental and Occupational Health Sciences Institute, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ (United States)

    2013-12-01

    Persistent neuroinflammation and microglial activation play an integral role in the pathogenesis of many neurological disorders. We investigated the role of voltage-gated sodium channels (VGSC) and Na{sup +}/H{sup +} exchangers (NHE) in the activation of immortalized microglial cells (BV-2) after lipopolysaccharide (LPS) exposure. LPS (10 and 100 ng/ml) caused a dose- and time-dependent accumulation of intracellular sodium [(Na{sup +}){sub i}] in BV-2 cells. Pre-treatment of cells with the VGSC antagonist tetrodotoxin (TTX, 1 μM) abolished short-term Na{sup +} influx, but was unable to prevent the accumulation of (Na{sup +}){sub i} observed at 6 and 24 h after LPS exposure. The NHE inhibitor cariporide (1 μM) significantly reduced accumulation of (Na{sup +}){sub i} 6 and 24 h after LPS exposure. Furthermore, LPS increased the mRNA expression and protein level of NHE-1 in a dose- and time-dependent manner, which was significantly reduced after co-treatment with TTX and/or cariporide. LPS increased production of TNF-α, ROS, and H{sub 2}O{sub 2} and expression of gp91{sup phox}, an active subunit of NADPH oxidase, in a dose- and time-dependent manner, which was significantly reduced by TTX or TTX + cariporide. Collectively, these data demonstrate a closely-linked temporal relationship between VGSC and NHE-1 in regulating function in activated microglia, which may provide avenues for therapeutic interventions aimed at reducing neuroinflammation. - Highlights: • LPS causes immediate increase in sodium through VGSC and subsequently through the NHE-1. • Inhibition of VGSC reduces increases in NHE-1 and gp91{sup phox}. • Inhibition of VGSC and NHE-1 reduces NADPH oxidase-mediated Tnf-α, ROS, and H{sub 2}O{sub 2} production. • NHE-1 and Na{sub v}1.6 may be viable targets for therapeutic interventions to reduce neuroinflammation in neurodegenerative disease.

  7. Microdamage induced calcium efflux from bone matrix activates intracellular calcium signaling in osteoblasts via L-type and T-type voltage-gated calcium channels.

    Science.gov (United States)

    Jung, Hyungjin; Best, Makenzie; Akkus, Ozan

    2015-07-01

    Mechanisms by which bone microdamage triggers repair response are not completely understood. It has been shown that calcium efflux ([Ca(2+)]E) occurs from regions of bone undergoing microdamage. Such efflux has also been shown to trigger intracellular calcium signaling ([Ca(2+)]I) in MC3T3-E1 cells local to damaged regions. Voltage-gated calcium channels (VGCCs) are implicated in the entry of [Ca(2+)]E to the cytoplasm. We investigated the involvement of VGCC in the extracellular calcium induced intracellular calcium response (ECIICR). MC3T3-E1 cells were subjected to one dimensional calcium efflux from their basal aspect which results in an increase in [Ca(2+)]I. This increase was concomitant with membrane depolarization and it was significantly reduced in the presence of Bepridil, a non-selective VGCC inhibitor. To identify specific type(s) of VGCC in ECIICR, the cells were treated with selective inhibitors for different types of VGCC. Significant changes in the peak intensity and the number of [Ca(2+)]I oscillations were observed when L-type and T-type specific VGCC inhibitors (Verapamil and NNC55-0396, respectively) were used. So as to confirm the involvement of L- and T-type VGCC in the context of microdamage, cells were seeded on devitalized notched bone specimen, which were loaded to induce microdamage in the presence and absence of Verapamil and NNC55-0396. The results showed significant decrease in [Ca(2+)]I activity of cells in the microdamaged regions of bone when L- and T-type blockers were applied. This study demonstrated that extracellular calcium increase in association with damage depolarizes the cell membrane and the calcium ions enter the cell cytoplasm by L- and T-type VGCCs.

  8. Dynamic Power Reduction of Digital Circuits by ClockGating

    Directory of Open Access Journals (Sweden)

    Varsha Dewre

    2017-04-01

    Full Text Available In this paper we have presented clock gating process for low power VLSI (very large scale integration circuit design. Clock gating is one of the most quite often used systems in RTL to shrink dynamic power consumption without affecting the performance of the design. One process involves inserting gating requisites in the RTL, which the synthesis tool translates to clock gating cells in the clock-path of a register bank. This helps to diminish the switching activity on the clock network, thereby decreasing dynamic power consumption within the design. Due to the fact the translation accomplished via the synthesis tool is solely combinational; it is referred to as combinational clock gating. This transformation does not alter the behavior of the register being gated

  9. A nanomechanical Fredkin gate.

    Science.gov (United States)

    Wenzler, Josef-Stefan; Dunn, Tyler; Toffoli, Tommaso; Mohanty, Pritiraj

    2014-01-08

    Irreversible logic operations inevitably discard information, setting fundamental limitations on the flexibility and the efficiency of modern computation. To circumvent the limit imposed by the von Neumann-Landauer (VNL) principle, an important objective is the development of reversible logic gates, as proposed by Fredkin, Toffoli, Wilczek, Feynman, and others. Here, we present a novel nanomechanical logic architecture for implementing a Fredkin gate, a universal logic gate from which any reversible computation can be built. In addition to verifying the truth table, we demonstrate operation of the device as an AND, OR, NOT, and FANOUT gate. Excluding losses due to resonator dissipation and transduction, which will require significant improvement in order to minimize the overall energy cost, our device requires an energy of order 10(4) kT per logic operation, similar in magnitude to state-of-the-art transistor-based technologies. Ultimately, reversible nanomechanical logic gates could play a crucial role in developing highly efficient reversible computers, with implications for efficient error correction and quantum computing.

  10. Brown Norway rats, a putative schizophrenia model, show increased electroencephalographic activity at rest and decreased event-related potential amplitude, power, and coherence in the auditory sensory gating paradigm.

    Science.gov (United States)

    Tomimatsu, Yoshiro; Hibino, Ryosuke; Ohta, Hiroyuki

    2015-08-01

    In recent schizophrenia clinical research, electroencephalographic (EEG) oscillatory activities induced by a sensory stimulus or behavioral tasks have gained considerable interest as functional and pathophysiological biomarkers. The Brown Norway (BN) rat is a putative schizophrenia model that shows naturally low sensorimotor gating and deficits in cognitive performance, although other phenotypes have not been studied. The present study aimed to investigate the neurophysiological features of BN rats, particularly EEG/event-related potential (ERP). EEG activity was recorded at rest and during the auditory sensory gating paradigm under an awake, freely moving condition. Frequency and ERP analysis were performed along with time-frequency analysis of evoked power and intertrial coherence. Compared with Wistar-Kyoto rats, a well-documented control line, BN rats showed increased EEG power at rest, particularly in the theta and gamma ranges. In ERP analysis, BN rats showed reduced N40-P20 amplitude but normal sensory gating. The rats also showed reduced evoked power and intertrial coherence against auditory stimuli. These results suggest that BN rats show features of EEG/ERP measures clinically relevant to schizophrenia and may provide additional opportunities for translational research.

  11. Improving Driver Performance. A Curriculum for Licensed Drivers.

    Science.gov (United States)

    Highway Users Federation for Safety and Mobility, Washington, DC.

    Curriculum material presented in this manual is for use in the development of an instructional program for drivers who either want or need to improve their driving performance. Three principal units are included: man and highway transportation, driver performance, and factors influencing driver behavior. Each unit is further divided into episodes…

  12. Simulators in driver training.

    NARCIS (Netherlands)

    2009-01-01

    In 2010, about 150 driving simulators were being used for the basic driver training in the Netherlands. According to theories about how people learn, simulator training has both advantages and disadvantages. In order to be able to learn something from a simulator, its technical quality must be

  13. Simulators in driver training.

    NARCIS (Netherlands)

    2009-01-01

    In 2010, about 150 driving simulators were being used for the basic driver training in the Netherlands. According to theories about how people learn, simulator training has both advantages and disadvantages. In order to be able to learn something from a simulator, its technical quality must be adequ

  14. Seven Performance Drivers.

    Science.gov (United States)

    Ross, Linda

    2003-01-01

    Recent work with automotive e-commerce clients led to the development of a performance analysis methodology called the Seven Performance Drivers, including: standards, incentives, capacity, knowledge and skill, measurement, feedback, and analysis. This methodology has been highly effective in introducing and implementing performance improvement.…

  15. The Gates at Pipe Spring National Monument, Arizona (gates)

    Data.gov (United States)

    National Park Service, Department of the Interior — This is an Arc/Info coverage consisting of 7 points representing gates at Pipe Spring National Monument, Arizona. The gates were collected by a Trimble GeoXT GPS...

  16. Amplifying genetic logic gates.

    Science.gov (United States)

    Bonnet, Jerome; Yin, Peter; Ortiz, Monica E; Subsoontorn, Pakpoom; Endy, Drew

    2013-05-03

    Organisms must process information encoded via developmental and environmental signals to survive and reproduce. Researchers have also engineered synthetic genetic logic to realize simpler, independent control of biological processes. We developed a three-terminal device architecture, termed the transcriptor, that uses bacteriophage serine integrases to control the flow of RNA polymerase along DNA. Integrase-mediated inversion or deletion of DNA encoding transcription terminators or a promoter modulates transcription rates. We realized permanent amplifying AND, NAND, OR, XOR, NOR, and XNOR gates actuated across common control signal ranges and sequential logic supporting autonomous cell-cell communication of DNA encoding distinct logic-gate states. The single-layer digital logic architecture developed here enables engineering of amplifying logic gates to control transcription rates within and across diverse organisms.

  17. Modeling the current of a double-gate MOSFET with very thin active region taking into account mobility dependence on the transverse electric field

    Science.gov (United States)

    Łukasiak, Lidia; Majkusiak, Bogdan

    2013-07-01

    Drain current and transconductance of a symmetrical, undoped double-gate MOSFET is modeled for the first time with mobility depending on both the applied voltage and position in the channel leading to analytical formulae. The obtained models are compared with simplified formulae assuming position-independent effective mobility. Good agreement is obtained in the case of one of the selected mobility models.

  18. A Quasi-Experimental Investigation of How the Gates Millennium Scholars Program Is Related to College Students' Time Use and Activities

    Science.gov (United States)

    DesJardins, Stephen L.; McCall, Brian P.; Ott, Molly; Kim, Jiyun

    2010-01-01

    A national scholarship program provided by the Bill & Melinda Gates Foundation is designed to improve access to and success in higher education for low-income high-achieving minority students by providing them with full tuition scholarships and non-monetary support. We use a regression discontinuity approach to investigate whether the receipt of…

  19. A method to model anticipatory postural control in driver braking events

    NARCIS (Netherlands)

    Osth, J.; Eliasson, E.; Happee, R.; Brolin, K.

    2014-01-01

    Human body models (HBMs) for vehicle occupant simulations have recently been extended with active muscles and postural control strategies. Feedback control has been used to model occupant responses to autonomous braking interventions. However, driver postural responses during driver initiated brakin

  20. Measuring and Ranking Value Drivers

    NARCIS (Netherlands)

    M.M. Akalu

    2002-01-01

    textabstractAnalysis of the strength of value drivers is crucial to understand their influence in the process of free cash flow generation. The paper addresses the issue of value driver measurement and ranking. The research reveals that, value drivers have similar pattern across industries.

  1. Measuring and Ranking Value Drivers

    NARCIS (Netherlands)

    M.M. Akalu

    2002-01-01

    textabstractAnalysis of the strength of value drivers is crucial to understand their influence in the process of free cash flow generation. The paper addresses the issue of value driver measurement and ranking. The research reveals that, value drivers have similar pattern across industries. Furtherm

  2. Sub-nanosecond Electron Emission from Electrically Gated Field Emitting Arrays

    CERN Document Server

    Paraliev, M; Gough, C; Kirk, E; Ivkovic, S

    2011-01-01

    Field Emitting Arrays (FEAs) are a promising alternative to the conventional cathodes in different vacuum electronic devices such as traveling wave tubes, electron accelerators and etc. Electrical gating and modulation capabilities, together with the ability to produce stable and homogeneous electron beam in high electric field environment are the key requirements for their practical application. Due to relatively high gate capacitance, fast controlling of FEA emission is difficult. In order to achieve sub-nanosecond, electrically controlled, FEA based electron emission a special pulsed gate driver was developed. Bipolar high voltage (HV)pulses are used to rapidly inject and remove charge form FEA gate electrode controlling quickly electron extraction gate voltage. Short electron emission pulses (<600 ps FWHM) were observed in low and high gradient (up to 12 MV/m) environment. First attempts were made to combine FEA based electron emission with radio frequency acceleration structures (1.5 GHz) using pulsed...

  3. Current status of hyperpolarization-activated cyclic nucleotide-gated cation channel%超极化激活环核苷酸门控阳离子通道的研究现状

    Institute of Scientific and Technical Information of China (English)

    严慧; 黄裕新; 王景杰

    2009-01-01

    @@ 0 引言 超极化激活环核苷酸门控的超极化阳离子通道(hyperpolarization-activated cyclic nucleotide-gated cation chan-nel,HCN)的研究起源于Ih的发现,Noma和Irisawa已经在研究窦房结起搏活动时发现这一离子流并命名为Ih(hyperpolar-ization-activated current),20世纪80年代初Di Francesco和Irisawa等

  4. Lateral driving assistance using embedded driver-vehicle-road mode

    OpenAIRE

    Glaser, S.; Mammar, S.; Sainte-Marie, J.

    2002-01-01

    This article presents a vehicle model devoted to the development of driver longitudinal and lateral assistance in curves. Each module of vehicle dynamics is described and several complexity levels are detailed. The adopted formalism for the description of the vehicle dynamics allows an easy interface to road, driver and control modules. Finally, a lateral active steering driving assistance is presented.

  5. Scanning Gate Spectroscopy on Nanoclusters

    OpenAIRE

    Gurevich, L.; Canali, L.; Kouwenhoven, L.P.

    1999-01-01

    A gated probe for scanning tunnelling microscopy (STM) has been developed. The probe extends normal STM operations by means of an additional electrode fabricated next to the tunnelling tip. The extra electrode does not make contact with the sample and can be used as a gate. We report on the recipe used for fabricating the tunnelling tip and the gate electrode on a silicon nitride cantilever. We demonstrate the functioning of the scanning gate probes by performing single-electron tunnelling sp...

  6. Biophysics, Pathophysiology and Pharmacology of Ion Channel Gating Pores

    Directory of Open Access Journals (Sweden)

    Adrien eMoreau

    2014-04-01

    Full Text Available Voltage sensor domain (VSDs are a feature of voltage gated ion channel (VGICs and voltage sensitive proteins. They are composed of four transmembrane (TM segments (S1 to S4. Currents leaking through VSDs are called omega or gating pore currents.Gating pores are caused by mutations of the highly conserved positively charged amino acids in the S4 segment that disrupt interactions between the S4 segment and the gating charge transfer center (GCTC. The GCTC separates the intracellular and extracellular water crevices. The disruption of S4–GCTC interactions allows these crevices to communicate and create a fast activating and non-inactivating alternative cation-selective permeation pathway of low conductance, or a gating pore.Gating pore currents have recently been shown to cause periodic paralysis phenotypes. There is also increasing evidence that gating pores are linked to several other familial diseases. For example, gating pores in Nav1.5 and Kv7.2 channels may underlie mixed arrhythmias associated with dilated cardiomyopathy (DCM phenotypes and peripheral nerve hyperexcitability (PNH respectively. There is little evidence for the existence of gating pore blockers. Moreover, it is known that a number of toxins bind to the VSD of a specific domain of Na+ channels. These toxins may thus modulate gating pore currents. This focus on the VSD motif opens up a new area of research centered on developing molecules to treat a number of cell excitability disorders such as epilepsy, cardiac arrhythmias, and pain.The purpose of the present review is to summarize existing knowledge of the pathophysiology, biophysics, and pharmacology of gating pore currents and to serve as a guide for future studies aimed at improving our understanding of gating pores and their pathophysiological roles.

  7. Stanford, Duke, Rice,... and Gates?

    Science.gov (United States)

    Carey, Kevin

    2009-01-01

    This article presents an open letter to Bill Gates. In his letter, the author suggests that Bill Gates should build a brand-new university, a great 21st-century institution of higher learning. This university will be unlike anything the world has ever seen. He asks Bill Gates not to stop helping existing colleges create the higher-education system…

  8. Stanford, Duke, Rice,... and Gates?

    Science.gov (United States)

    Carey, Kevin

    2009-01-01

    This article presents an open letter to Bill Gates. In his letter, the author suggests that Bill Gates should build a brand-new university, a great 21st-century institution of higher learning. This university will be unlike anything the world has ever seen. He asks Bill Gates not to stop helping existing colleges create the higher-education system…

  9. The four-gate transistor

    Science.gov (United States)

    Mojarradi, M. M.; Cristoveanu, S.; Allibert, F.; France, G.; Blalock, B.; Durfrene, B.

    2002-01-01

    The four-gate transistor or G4-FET combines MOSFET and JFET principles in a single SOI device. Experimental results reveal that each gate can modulate the drain current. Numerical simulations are presented to clarify the mechanisms of operation. The new device shows enhanced functionality, due to the combinatorial action of the four gates, and opens rather revolutionary applications.

  10. What Are Drivers for Informal Learning?

    Science.gov (United States)

    Schürmann, Eva; Beausaert, Simon

    2016-01-01

    Purpose: The topic of informal learning at work has received increasing attention in the past years. The purpose of this study is to explore in which informal learning activities employees engage and what are the drivers for informal learning. Design/Methodology/Approach: Semi-structured interviews were taken from ten human resources (HR) and ten…

  11. Automobile Driver Fingerprinting

    Directory of Open Access Journals (Sweden)

    Enev Miro

    2016-01-01

    Full Text Available Today’s automobiles leverage powerful sensors and embedded computers to optimize efficiency, safety, and driver engagement. However the complexity of possible inferences using in-car sensor data is not well understood. While we do not know of attempts by automotive manufacturers or makers of after-market components (like insurance dongles to violate privacy, a key question we ask is: could they (or their collection and later accidental leaks of data violate a driver’s privacy? In the present study, we experimentally investigate the potential to identify individuals using sensor data snippets of their natural driving behavior. More specifically we record the in-vehicle sensor data on the controllerarea- network (CAN of a typical modern vehicle (popular 2009 sedan as each of 15 participants (a performed a series of maneuvers in an isolated parking lot, and (b drove the vehicle in traffic along a defined ~ 50 mile loop through the Seattle metropolitan area. We then split the data into training and testing sets, train an ensemble of classifiers, and evaluate identification accuracy of test data queries by looking at the highest voted candidate when considering all possible one-vs-one comparisons. Our results indicate that, at least among small sets, drivers are indeed distinguishable using only incar sensors. In particular, we find that it is possible to differentiate our 15 drivers with 100% accuracy when training with all of the available sensors using 90% of driving data from each person. Furthermore, it is possible to reach high identification rates using less than 8 minutes of training data. When more training data is available it is possible to reach very high identification using only a single sensor (e.g., the brake pedal. As an extension, we also demonstrate the feasibility of performing driver identification across multiple days of data collection

  12. Rational Design of a Fusion Protein to Exhibit Disulfide-Mediated Logic Gate Behavior

    Science.gov (United States)

    2015-01-01

    Synthetic cellular logic gates are primarily built from gene circuits owing to their inherent modularity. Single proteins can also possess logic gate functions and offer the potential to be simpler, quicker, and less dependent on cellular resources than gene circuits. However, the design of protein logic gates that are modular and integrate with other cellular components is a considerable challenge. As a step toward addressing this challenge, we describe the design, construction, and characterization of AND, ORN, and YES logic gates built by introducing disulfide bonds into RG13, a fusion of maltose binding protein and TEM-1 β-lactamase for which maltose is an allosteric activator of enzyme activity. We rationally designed these disulfide bonds to manipulate RG13’s allosteric regulation mechanism such that the gating had maltose and reducing agents as input signals, and the gates could be toggled between different gating functions using redox agents, although some gates performed suboptimally. PMID:25144732

  13. Redox control of 20S proteasome gating.

    Science.gov (United States)

    Silva, Gustavo M; Netto, Luis E S; Simões, Vanessa; Santos, Luiz F A; Gozzo, Fabio C; Demasi, Marcos A A; Oliveira, Cristiano L P; Bicev, Renata N; Klitzke, Clécio F; Sogayar, Mari C; Demasi, Marilene

    2012-06-01

    The proteasome is the primary contributor in intracellular proteolysis. Oxidized or unstructured proteins can be degraded via a ubiquitin- and ATP-independent process by the free 20S proteasome (20SPT). The mechanism by which these proteins enter the catalytic chamber is not understood thus far, although the 20SPT gating conformation is considered to be an important barrier to allowing proteins free entrance. We have previously shown that S-glutathiolation of the 20SPT is a post-translational modification affecting the proteasomal activities. The goal of this work was to investigate the mechanism that regulates 20SPT activity, which includes the identification of the Cys residues prone to S-glutathiolation. Modulation of 20SPT activity by proteasome gating is at least partially due to the S-glutathiolation of specific Cys residues. The gate was open when the 20SPT was S-glutathiolated, whereas following treatment with high concentrations of dithiothreitol, the gate was closed. S-glutathiolated 20SPT was more effective at degrading both oxidized and partially unfolded proteins than its reduced form. Only 2 out of 28 Cys were observed to be S-glutathiolated in the proteasomal α5 subunit of yeast cells grown to the stationary phase in glucose-containing medium. We demonstrate a redox post-translational regulatory mechanism controlling 20SPT activity. S-glutathiolation is a post-translational modification that triggers gate opening and thereby activates the proteolytic activities of free 20SPT. This process appears to be an important regulatory mechanism to intensify the removal of oxidized or unstructured proteins in stressful situations by a process independent of ubiquitination and ATP consumption. Antioxid. Redox Signal. 16, 1183-1194.

  14. Allosteric gating mechanism underlies the flexible gating of KCNQ1 potassium channels.

    Science.gov (United States)

    Osteen, Jeremiah D; Barro-Soria, Rene; Robey, Seth; Sampson, Kevin J; Kass, Robert S; Larsson, H Peter

    2012-05-01

    KCNQ1 (Kv7.1) is a unique member of the superfamily of voltage-gated K(+) channels in that it displays a remarkable range of gating behaviors tuned by coassembly with different β subunits of the KCNE family of proteins. To better understand the basis for the biophysical diversity of KCNQ1 channels, we here investigate the basis of KCNQ1 gating in the absence of β subunits using voltage-clamp fluorometry (VCF). In our previous study, we found the kinetics and voltage dependence of voltage-sensor movements are very similar to those of the channel gate, as if multiple voltage-sensor movements are not required to precede gate opening. Here, we have tested two different hypotheses to explain KCNQ1 gating: (i) KCNQ1 voltage sensors undergo a single concerted movement that leads to channel opening, or (ii) individual voltage-sensor movements lead to channel opening before all voltage sensors have moved. Here, we find that KCNQ1 voltage sensors move relatively independently, but that the channel can conduct before all voltage sensors have activated. We explore a KCNQ1 point mutation that causes some channels to transition to the open state even in the absence of voltage-sensor movement. To interpret these results, we adopt an allosteric gating scheme wherein KCNQ1 is able to transition to the open state after zero to four voltage-sensor movements. This model allows for widely varying gating behavior, depending on the relative strength of the opening transition, and suggests how KCNQ1 could be controlled by coassembly with different KCNE family members.

  15. The storm that rocks the boat: the systemic impact of gated communities on urban sustainability

    Directory of Open Access Journals (Sweden)

    Karina Landman

    2007-09-01

    Full Text Available This paper is concerned with the impact and implications of gated communities on urban sustainability. This is investigated making use of an overarching methodological framework based on the internationally accepted Driver-Pressure-State-Impact-Response (DPSIR model, developed by the OECD. Additional to the simple causal flow from drivers to responses are the dynamic relationships between these five aspects. The paper discusses each of these issues and the relationships between them as they pertain to gated communities in South Africa. Gated communities, as complex systems, necessitate the consideration of a multiplicity of feedback loops with internal rates of flow that are determined by non-linear relationships. Only in this way can the full extent of their impact and implications on urban sustainability be assessed.

  16. High permittivity gate dielectric materials

    CERN Document Server

    2013-01-01

    "The book comprehensively covers all the current and the emerging areas of the physics and the technology of high permittivity gate dielectric materials, including, topics such as MOSFET basics and characteristics, hafnium-based gate dielectric materials, Hf-based gate dielectric processing, metal gate electrodes, flat-band and threshold voltage tuning, channel mobility, high-k gate stack degradation and reliability, lanthanide-based high-k gate stack materials, ternary hafnia and lanthania based high-k gate stack films, crystalline high-k oxides, high mobility substrates, and parameter extraction. Each chapter begins with the basics necessary for understanding the topic, followed by a comprehensive review of the literature, and ultimately graduating to the current status of the technology and our scientific understanding and the future prospects."

  17. Noise Gating Solar Images

    Science.gov (United States)

    DeForest, Craig; Seaton, Daniel B.; Darnell, John A.

    2017-08-01

    I present and demonstrate a new, general purpose post-processing technique, "3D noise gating", that can reduce image noise by an order of magnitude or more without effective loss of spatial or temporal resolution in typical solar applications.Nearly all scientific images are, ultimately, limited by noise. Noise can be direct Poisson "shot noise" from photon counting effects, or introduced by other means such as detector read noise. Noise is typically represented as a random variable (perhaps with location- or image-dependent characteristics) that is sampled once per pixel or once per resolution element of an image sequence. Noise limits many aspects of image analysis, including photometry, spatiotemporal resolution, feature identification, morphology extraction, and background modeling and separation.Identifying and separating noise from image signal is difficult. The common practice of blurring in space and/or time works because most image "signal" is concentrated in the low Fourier components of an image, while noise is evenly distributed. Blurring in space and/or time attenuates the high spatial and temporal frequencies, reducing noise at the expense of also attenuating image detail. Noise-gating exploits the same property -- "coherence" -- that we use to identify features in images, to separate image features from noise.Processing image sequences through 3-D noise gating results in spectacular (more than 10x) improvements in signal-to-noise ratio, while not blurring bright, resolved features in either space or time. This improves most types of image analysis, including feature identification, time sequence extraction, absolute and relative photometry (including differential emission measure analysis), feature tracking, computer vision, correlation tracking, background modeling, cross-scale analysis, visual display/presentation, and image compression.I will introduce noise gating, describe the method, and show examples from several instruments (including SDO

  18. A quantum Fredkin gate.

    Science.gov (United States)

    Patel, Raj B; Ho, Joseph; Ferreyrol, Franck; Ralph, Timothy C; Pryde, Geoff J

    2016-03-01

    Minimizing the resources required to build logic gates into useful processing circuits is key to realizing quantum computers. Although the salient features of a quantum computer have been shown in proof-of-principle experiments, difficulties in scaling quantum systems have made more complex operations intractable. This is exemplified in the classical Fredkin (controlled-SWAP) gate for which, despite theoretical proposals, no quantum analog has been realized. By adding control to the SWAP unitary, we use photonic qubit logic to demonstrate the first quantum Fredkin gate, which promises many applications in quantum information and measurement. We implement example algorithms and generate the highest-fidelity three-photon Greenberger-Horne-Zeilinger states to date. The technique we use allows one to add a control operation to a black-box unitary, something that is impossible in the standard circuit model. Our experiment represents the first use of this technique to control a two-qubit operation and paves the way for larger controlled circuits to be realized efficiently.

  19. Driver Fatigue Features Extraction

    Directory of Open Access Journals (Sweden)

    Gengtian Niu

    2014-01-01

    Full Text Available Driver fatigue is the main cause of traffic accidents. How to extract the effective features of fatigue is important for recognition accuracy and traffic safety. To solve the problem, this paper proposes a new method of driver fatigue features extraction based on the facial image sequence. In this method, first, each facial image in the sequence is divided into nonoverlapping blocks of the same size, and Gabor wavelets are employed to extract multiscale and multiorientation features. Then the mean value and standard deviation of each block’s features are calculated, respectively. Considering the facial performance of human fatigue is a dynamic process that developed over time, each block’s features are analyzed in the sequence. Finally, Adaboost algorithm is applied to select the most discriminating fatigue features. The proposed method was tested on a self-built database which includes a wide range of human subjects of different genders, poses, and illuminations in real-life fatigue conditions. Experimental results show the effectiveness of the proposed method.

  20. Fast SCR Thyratron Driver

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, M.N.; /SLAC

    2007-06-18

    As part of an improvement project on the linear accelerator at SLAC, it was necessary to replace the original thyratron trigger generator, which consisted of two chassis, two vacuum tubes, and a small thyratron. All solid-state, fast rise, and high voltage thyratron drivers, therefore, have been developed and built for the 244 klystron modulators. The rack mounted, single chassis driver employs a unique way to control and generate pulses through the use of an asymmetric SCR, a PFN, a fast pulse transformer, and a saturable reactor. The resulting output pulse is 2 kV peak into 50 {Omega} load with pulse duration of 1.5 {mu}s FWHM at 180 Hz. The pulse risetime is less than 40 ns with less than 1 ns jitter. Various techniques are used to protect the SCR from being damaged by high voltage and current transients due to thyratron breakdowns. The end-of-line clipper (EOLC) detection circuit is also integrated into this chassis to interrupt the modulator triggering in the event a high percentage of line reflections occurred.

  1. Dextromethorphan in Wisconsin drivers.

    Science.gov (United States)

    Cochems, Amy; Harding, Patrick; Liddicoat, Laura

    2007-05-01

    Dextromethorphan is a synthetic analogue of codeine used in hundreds of over-the-counter medications for its antitussive effects. There have been numerous reports of dextromethorphan abuse by young adults. Dextromethorphan can produce psychoactive effects similar to that of marijuana, and higher doses will produce dissociative effects, including sensory enhancement and hallucinations. The Wisconsin State Laboratory of Hygiene examined data from blood samples submitted from January 1999 through December 2004 to determine the incidence of dextromethorphan in suspected impaired drivers. A total of 108 samples were found to be positive for dextromethorphan during this time. Dextromethorphan concentrations in these cases ranged from less than 5 to 1800 ng/mL (mean 207 ng/mL), compared to an expected therapeutic concentration range of 0.5-5.9 ng/mL. Overall, the highest dextromethorphan concentrations observed were in males aged 16-20 years. Ninety-six percent of the specimens included in this study were also found to be positive for drugs other than dextromethorphan. A review of police and drug recognition expert reports from several of these cases showed that dextromethorphan-impaired drivers exhibited poor psychomotor performance on standardized field sobriety tests, horizontal gaze nystagmus, vertical gaze nystagmus, and overall signs of central nervous system depression.

  2. Driver behaviour at roadworks.

    Science.gov (United States)

    Walker, Guy; Calvert, Malcolm

    2015-11-01

    There is an incompatibility between how transport engineers think drivers behave in roadworks and how they actually behave. As a result of this incompatibility we are losing approximately a lane's worth of capacity in addition to those closed by the roadworks themselves. The problem would have little significance were it not for the fact a lane of motorway costs approx. £30 m per mile to construct and £43 k a year to maintain, and that many more roadworks are planned as infrastructure constructed 40 or 50 years previously reaches a critical stage in its lifecycle. Given current traffic volumes, and the sensitivity of road networks to congestion, the effects of roadworks need to be accurately assessed. To do this requires a new ergonomic approach. A large-scale observational study of real traffic conditions was used to identify the issues and impacts, which were then mapped to the ergonomic knowledge-base on driver behaviour, and combined to developed practical guidelines to help in modelling future roadworks scenarios with greater behavioural accuracy. Also stemming from the work are novel directions for the future ergonomic design of roadworks themselves.

  3. VOLTAGE-GATED NA+ CHANNEL BLOCKERS ATTENUATE THE TOXICITY OF PROLONGED REPETITIVE ACTIVITY IN A MOUSE MODEL OF CMT1B

    DEFF Research Database (Denmark)

    Alvarez Herrero, Susana; Rosberg, M. R.; Moldovan, M.

    2016-01-01

    Prolonged high frequency electrical stimulation (RS) was found to precipitate motor axon degeneration in P0+/− mice, a model of demyelinating Charcot-Marie-Tooth disease (CMT1B). We hypothesized that this was due to the associated changes in voltage-gated Na + channel (VGSC) isoforms with ectopic.......). Investigations were carried out in 1-year-old WT, P0+/− and NaV1.8 knockouts (P0+/−SNS) mice. Tibial nerve RS was carried out under anesthesia using interrupted trains of 200 Hz for 3 hours, which is not neurotoxic in WT. Nerve function was monitored by conventional conduction studies and nerve excitability...

  4. Driver style and driver skills – clustering drivers differing in their potential danger in traffic

    DEFF Research Database (Denmark)

    Martinussen, Laila Marianne; Møller, Mette; Prato, Carlo Giacomo

    The Driver Behavior Questionnaire (DBQ) and the Driver Skill Inventory (DSI) are two of the most frequently used measures of driving style and driving skill. The motivation behind the present study was to test drivers’ insight into their own driving ability based on a combined use of the DBQ......, annual mileage and accident involvement. 3908 drivers aged 18–84 participated in the survey. The results suggested that the drivers have good insight into their own driving ability, as the driving skill level mirrored the frequency of aberrant driving behaviors. K-means cluster analysis revealed four...... and the DSI. Moreover, the joint use of the two instruments was applied to identify sub-groups of drivers that differ in their potential danger in traffic, as well as to test for heterogeneity across the population, namely whether the sub-groups of drivers differed in characteristics such as age, gender...

  5. A RE-ASSESSMENT OF OLDER DRIVERS AS A ROAD SAFETY RISK

    Directory of Open Access Journals (Sweden)

    Jim LANGFORD

    2006-01-01

    Full Text Available Older drivers are frequently viewed as overly represented in crashes, particularly when crash involvement per distance travelled is considered. This perception has led to a call for tighter licensing conditions for older drivers, a policy which inevitably results in mobility restrictions for at least some drivers. However there is a growing body of research evidence which shows that as a group, older drivers represent no greater road risk than drivers from other age groups once different levels of driving activity are taken into account. This paper has examined aspects of older drivers' fitness to drive based on survey data and off-road and on-road driving performance from a sample of 905 New Zealand older drivers. The results show that policies which target all older drivers and lead to licensing and mobility restrictions cannot be justified from a safety basis.

  6. Gate complexity using Dynamic Programming

    OpenAIRE

    Sridharan, Srinivas; Gu, Mile; James, Matthew R.

    2008-01-01

    The relationship between efficient quantum gate synthesis and control theory has been a topic of interest in the quantum control literature. Motivated by this work, we describe in the present article how the dynamic programming technique from optimal control may be used for the optimal synthesis of quantum circuits. We demonstrate simulation results on an example system on SU(2), to obtain plots related to the gate complexity and sample paths for different logic gates.

  7. Localizing a gate in CFTR

    OpenAIRE

    Gao, Xiaolong; Hwang, Tzyh-Chang

    2015-01-01

    Cystic fibrosis transmembrane conductance regulator (CFTR), albeit a bona fide member of the ATP-binding cassette (ABC) transporter superfamily, is an ATP-gated chloride channel. However, phylogenetic analysis has led to a popular conjecture that CFTR evolves from a primordial ABC exporter by simply degenerating the cytoplasmic gate. This degraded transporter hypothesis predicts that CFTR’s gate is located at the external end of the substrate translocation pathway as the one documented in the...

  8. GATE TYPE SELECTION BASED ON FUZZY MAPPING

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Gate type selection is very important for mould design. Improper gate type may lead to poor product quality and low production efficiency. Although numerical simulation approach could be used to optimize gate location, the determination of gate type is still up to designers' experience. A novel method for selecting gate type based on fuzzy logic is proposed. The proposed methodology follows three steps:Design requirements for gate is extracted and generalized; Possible gate types (design schemes) are presented; The fuzzy mapping relationship between gate design requirements and gate design scheme is established based on fuzzy composition and fuzzy relation transition matrices that are assigned by domain experts.

  9. Expert Oracle GoldenGate

    CERN Document Server

    Prusinski, Ben; Chung, Richard

    2011-01-01

    Expert Oracle GoldenGate is a hands-on guide to creating and managing complex data replication environments using the latest in database replication technology from Oracle. GoldenGate is the future in replication technology from Oracle, and aims to be best-of-breed. GoldenGate supports homogeneous replication between Oracle databases. It supports heterogeneous replication involving other brands such as Microsoft SQL Server and IBM DB2 Universal Server. GoldenGate is high-speed, bidirectional, highly-parallelized, and makes only a light impact on the performance of databases involved in replica

  10. Drivers of Collaborative Advantage

    DEFF Research Database (Denmark)

    Weihe, Gudrid

    Drawing upon extant alliance literature, this article substantiates the argument that we need to look beyond mere structural and formative aspects of cooperation in order to fully understand the performance antecedents of public-private partnerships. Currently, scholarly work on operational...... processes and behavioural dimensions is practically non-existent. This article tries to remedy the current gap in the literature by reviewing research findings on interfirm collaboration (alliances). On that basis a conceptual framework for analyzing partnership processes is developed. Finally......, the antecedents of collaborative advantage are theoretically examined, and the organizational competences contributing to collaborative success are identified. The conclusion is that operational processes and social dynamics are vital drivers of collaborative advantage. Another significant conclusion...

  11. Drivers for Welfare Innovation

    DEFF Research Database (Denmark)

    Wegener, Charlotte

    2015-01-01

    Innovation has become a key goal towards which teaching and workplace learning needs to be directed. Now perceived as germane and even necessary in almost all kinds of welfare work, the innovation potential in everyday practices and ways of allowing for employer creativity have become a highly...... on the empirical material, the paper proposes a ‘driver’ model for context sensitive research of innovation in welfare workplaces. The model involves three elements which can be regarded as drivers for innovation: i) craft (i.e. professional skills and knowledge), ii) levers (i.e. experiments and adjustment...... that are not necessarily perceived, performed, and changed in phases. A pragmatic and situated perspective on welfare innovation suggests a conception of welfare innovation which is not translated from firm innovation, but derived directly from welfare contexts....

  12. Power Gating Based Ground Bounce Noise Reduction

    Directory of Open Access Journals (Sweden)

    M. Uma Maheswari

    2014-08-01

    Full Text Available As low power circuits are most popular the decrease in supply voltage leads to increase in leakage power with respect to the technology scaling. So for removing this kind of leakages and to provide a better power efficiency many power gating techniques are used. But the leakage due to ground connection to the active part of the circuit is very high rather than all other leakages. As it is mainly due to the back EMF of the ground connection it was called it as ground bounce noise. To reduce this noise different methodologies are designed. In this paper the design of such an efficient technique related to ground bounce noise reduction using power gating circuits and comparing the results using DSCH and Microwind low power tools. In this paper the analysis of adders such as full adders using different types of power gated circuits using low power VLSI design techniques and to present the comparison results between different power gating methods.

  13. A holistic perspective on corporate sustainability drivers

    NARCIS (Netherlands)

    Lozano, Rodrigo|info:eu-repo/dai/nl/36412380X

    2015-01-01

    Since company boards are increasingly discussing 'sustainability', it becomes necessary to examine the nature of sustainability drivers. Most approaches to corporate sustainability drivers have focused either on internal or external drivers. This paper is aimed at providing a more holistic

  14. Social capital, health, and elderly driver status.

    Science.gov (United States)

    Isbel, Stephen T; Berry, Helen L

    2016-03-01

    Driving a car enables many people to engage in meaningful activities that, in turn, help develop and maintain personal social capital. Social capital, a combination of community participation and social cohesion, is important in maintaining well-being. This paper argues that social capital can provide a framework for investigating the general role of transportation and driving a car specifically to access activities that contribute to connectedness and well-being among older people. This paper proposes theoretically plausible and empirically testable hypotheses about the relationship between driver status, social capital, and well-being. A longitudinal study may provide a new way of understanding, and thus of addressing, the well-being challenges that occur when older people experience restrictions to, or loss of, their driver's license.

  15. Piezoconductivity of gated suspended graphene

    NARCIS (Netherlands)

    Medvedyeva, M.V.; Blanter, Y.M.

    2011-01-01

    We investigate the conductivity of graphene sheet deformed over a gate. The effect of the deformation on the conductivity is twofold: The lattice distortion can be represented as pseudovector potential in the Dirac equation formalism, whereas the gate causes inhomogeneous density redistribution. We

  16. Works close to gate B

    CERN Multimedia

    GS Department

    2011-01-01

    In connection to the TRAM project, drainage works will be carried out close to gate B until the end of next week. In order to avoid access problems, if arriving by car, please use gates A and E. Department of General Infrastructure Services (GS) GS-SE Group

  17. Penn State DOE GATE Program

    Energy Technology Data Exchange (ETDEWEB)

    Anstrom, Joel

    2012-08-31

    The Graduate Automotive Technology Education (GATE) Program at The Pennsylvania State University (Penn State) was established in October 1998 pursuant to an award from the U.S. Department of Energy (U.S. DOE). The focus area of the Penn State GATE Program is advanced energy storage systems for electric and hybrid vehicles.

  18. Vehicle Dynamics Approach to Driver Warning

    Directory of Open Access Journals (Sweden)

    Youssef A. Ghoneim

    2013-01-01

    Full Text Available This paper discusses a concept for enhanced active safety by introducing a driver warning system based on vehicle dynamics that predicts a potential loss of control condition prior to stability control activation. This real-time warning algorithm builds on available technologies such as the Electronic Stability Control (ESC. The driver warning system computes several indices based on yaw rate, side-slip velocity, and vehicle understeer using ESC sensor suite. An arbitrator block arbitrates between the different indices and determines the status index of the driving vehicle. The status index is compared to predetermined stability levels which correspond to high and low stability levels. If the index exceeds the high stability level, a warning signal (haptic, acoustic, or visual is issued to alert the driver of a potential loss of control and ESC activation. This alert will remain in effect until the index is less than the low stability level at which time the warning signal will be terminated. A vehicle speed advisory algorithm is integrated with the warning algorithm to provide a desired vehicle speed of a vehicle traveling on a curve. Simulation results and vehicle tests were conducted to illustrate the effectiveness of the warning algorithm.

  19. Logic Gates with Ion Transistors

    CERN Document Server

    Grebel, Haim

    2016-01-01

    Electronic logic gates are the basic building blocks of every computing and micro controlling system. Logic gates are made of switches, such as diodes and transistors. Ion-selective, ionic switches may emulate electronic switches [1-8]. If we ever want to create artificial bio-chemical circuitry, then we need to move a step further towards ion-logic circuitry. Here we demonstrate ion XOR and OR gates with electrochemical cells, and specifically, with two wet-cell batteries. In parallel to vacuum tubes, the batteries were modified to include a third, permeable and conductive mid electrode (the gate), which was placed between the anode and cathode in order to affect the ion flow through it. The key is to control the cell output with a much smaller biasing power, as demonstrated here. A successful demonstration points to self-powered ion logic gates.

  20. A quality improvement tool - driver diagram: a model of driver diagram to reduce primary caesarean section rates

    Directory of Open Access Journals (Sweden)

    Naima Fathima

    2016-05-01

    Results: Various quality improvement tools can be used in the clinical context. Among them, driver diagram is most widely used at the start of an improvement initiative. The driver diagram in this article shows its applicability in one of the clinical aspects of obstetrics, to reduce primary caesarean section rates. Conclusions: Driver diagram is an easy and a simple tool widely used in quality improvement activities. It is essential to use at the beginning of improvement initiatives. [Int J Res Med Sci 2016; 4(5.000: 1339-1342

  1. Development drivers for waste management.

    Science.gov (United States)

    Wilson, David C

    2007-06-01

    This paper identifies six broad groups of drivers for development in waste management. Public health led to the emergence of formalized waste collection systems in the nineteenth century, and remains a key driver in developing countries. Environmental protection came to the forefront in the 1970s, with an initial focus on eliminating uncontrolled disposal, followed by the systematic increasing of technical standards. Today, developing countries seem still to be struggling with these first steps; while climate change is also emerging as a key driver. The resource value of waste, which allows people to make a living from discarded materials, was an important driver historically, and remains so in developing countries today. A current trend in developed countries is closing the loop, moving from the concept of 'end-of-pipe' waste management towards a more holistic resource management. Two underpinning groups of drivers are institutional and responsibility issues, and public awareness. There is no, one single driver for development in waste management: the balance between these six groups of drivers has varied over time, and will vary between countries depending on local circumstances, and between stakeholders depending on their perspective. The next appropriate steps towards developing a sustainable, integrated waste management system will also vary in each local situation.

  2. Bimetal switches in an AND logic gate

    Science.gov (United States)

    Lubrica, Joel V.; Lubrica, Quantum Yuri B.

    2016-09-01

    In this frontline, we use bimetal switches to provide inputs in an electrical AND logic gate. These switches can be obtained from the pre-heat starters of fluorescent lamps, by safely removing the glass enclosure. They may be activated by small open flames. This frontline has a historical aspect because fluorescent lamps, together with pre-heat starters, are now being replaced by compact fluorescent, halogen, and LED lamps.

  3. Emergence of ion channel modal gating from independent subunit kinetics.

    Science.gov (United States)

    Bicknell, Brendan A; Goodhill, Geoffrey J

    2016-09-06

    Many ion channels exhibit a slow stochastic switching between distinct modes of gating activity. This feature of channel behavior has pronounced implications for the dynamics of ionic currents and the signaling pathways that they regulate. A canonical example is the inositol 1,4,5-trisphosphate receptor (IP3R) channel, whose regulation of intracellular Ca(2+) concentration is essential for numerous cellular processes. However, the underlying biophysical mechanisms that give rise to modal gating in this and most other channels remain unknown. Although ion channels are composed of protein subunits, previous mathematical models of modal gating are coarse grained at the level of whole-channel states, limiting further dialogue between theory and experiment. Here we propose an origin for modal gating, by modeling the kinetics of ligand binding and conformational change in the IP3R at the subunit level. We find good agreement with experimental data over a wide range of ligand concentrations, accounting for equilibrium channel properties, transient responses to changing ligand conditions, and modal gating statistics. We show how this can be understood within a simple analytical framework and confirm our results with stochastic simulations. The model assumes that channel subunits are independent, demonstrating that cooperative binding or concerted conformational changes are not required for modal gating. Moreover, the model embodies a generally applicable principle: If a timescale separation exists in the kinetics of individual subunits, then modal gating can arise as an emergent property of channel behavior.

  4. Voltage-dependent gating of hERG potassium channels

    Directory of Open Access Journals (Sweden)

    Yen May eCheng

    2012-05-01

    Full Text Available The mechanisms by which voltage-gated channels sense changes in membrane voltage and energetically couple this with opening of the ion conducting pore has been the source of significant interest. In voltage-gated potassium (Kv channels, much of our knowledge in this area comes from Shaker-type channels, for which voltage-dependent gating is quite rapid. In these channels, activation and deactivation are associated with rapid reconfiguration of the voltage-sensing domain unit that is electromechanically coupled, via the S4-S5 linker helix, to the rate-limiting opening of an intracellular pore gate. However, fast voltage-dependent gating kinetics are not typical of all Kv channels, such as Kv11.1 (human ether-a-go-go related gene, hERG, which activates and deactivates very slowly. Compared to Shaker channels, our understanding of the mechanisms underlying slow hERG gating is much poorer. Here, we present a comparative review of the structure-function relationships underlying voltage-dependent gating in Shaker and hERG channels, with a focus on the roles of the voltage sensing domain and the S4-S5 linker that couples voltage sensor movements to the pore. Measurements of gating current kinetics and fluorimetric analysis of voltage sensor movement are consistent with models suggesting that the hERG activation pathway contains a voltage independent step, which limits voltage sensor transitions. Constraints upon hERG voltage sensor movement may result from loose packing of the S4 helices and additional intra-voltage sensor counter charge interactions. More recent data suggest that key amino acid differences in the hERG voltage sensing unit and S4-S5 linker, relative to fast activating Shaker-type Kv channels, may also contribute to the increased stability of the resting state of the voltage sensor.

  5. Cnidarian Toxins Acting on Voltage-Gated Ion Channels

    Directory of Open Access Journals (Sweden)

    Robert M. Greenberg

    2006-04-01

    Full Text Available Abstract: Voltage-gated ion channels generate electrical activity in excitable cells. As such, they are essential components of neuromuscular and neuronal systems, and are targeted by toxins from a wide variety of phyla, including the cnidarians. Here, we review cnidarian toxins known to target voltage-gated ion channels, the specific channel types targeted, and, where known, the sites of action of cnidarian toxins on different channels.

  6. Peer pressure and risk taking in young drivers' speeding behavior

    OpenAIRE

    GHEORGHIU, Alexandra; DELHOMME, Patricia; FELONNEAU, Marie Line

    2015-01-01

    Although many countermeasures have been implemented in Europe, young drivers continue to have a high rate of involvement in car crashes. Their crash rate is higher in presence of peer passengers than when driving alone. Peer presence could contribute toward explaining this involvement, especially regarding speeding. Peers are known to often influence young drivers' risky behaviors through proximal (direct and indirect active pressures) and distal (passive pressure) forms of int...

  7. Rosalind Driver studentships

    Science.gov (United States)

    1999-11-01

    The School of Education at King's College London can now offer funded studentships to those wishing to undertake research in science education. These studentships, which are funded through the generous benefaction of the late Rosalind Driver, can be for a full-time student (over a maximum of three years) or several part-time students (a maximum of six years). Applications from anyone working in science education are welcome but preference will be given to those originating from practising science teachers. Applicants will be expected to register for the award of a MPhil/PhD or EdD and are normally expected to have a first degree. Preliminary ideas about a topic for investigation would also be helpful. Further details and application forms are obtainable from Chiz Dube, School of Education, King's College London, Franklin - Wilkins Building, Waterloo Road, London SE1 8WA (tel: 020-7848-3089, e-mail: chiz.dube@kcl.ac.uk). The deadline for the first round of applications was the middle of October, but preliminary informal enquiries may be made to Dr Jonathan Osborne at the School of Education (tel: 020-7848-3094, e-mail: jonathan.osborne@kcl.ac.uk).

  8. Single electron charge sensitivity of liquid-gated carbon nanotube transistors.

    Science.gov (United States)

    Sharf, Tal; Wang, Neng-Ping; Kevek, Joshua W; Brown, Morgan A; Wilson, Heather; Heinze, Stefan; Minot, Ethan D

    2014-09-10

    Random telegraph signals corresponding to activated charge traps were observed with liquid-gated CNT FETs. The high signal-to-noise ratio that we observe demonstrates that single electron charge sensing is possible with CNT FETs in liquids at room temperature. We have characterized the gate-voltage dependence of the random telegraph signals and compared to theoretical predictions. The gate-voltage dependence clearly identifies the sign of the activated trapped charge.

  9. Modularity Induced Gating and Delays in Neuronal Networks.

    Science.gov (United States)

    Shein-Idelson, Mark; Cohen, Gilad; Ben-Jacob, Eshel; Hanein, Yael

    2016-04-01

    Neural networks, despite their highly interconnected nature, exhibit distinctly localized and gated activation. Modularity, a distinctive feature of neural networks, has been recently proposed as an important parameter determining the manner by which networks support activity propagation. Here we use an engineered biological model, consisting of engineered rat cortical neurons, to study the role of modular topology in gating the activity between cell populations. We show that pairs of connected modules support conditional propagation (transmitting stronger bursts with higher probability), long delays and propagation asymmetry. Moreover, large modular networks manifest diverse patterns of both local and global activation. Blocking inhibition decreased activity diversity and replaced it with highly consistent transmission patterns. By independently controlling modularity and disinhibition, experimentally and in a model, we pose that modular topology is an important parameter affecting activation localization and is instrumental for population-level gating by disinhibition.

  10. Chimeric agents derived from the functionalized amino acid, lacosamide, and the α-aminoamide, safinamide: evaluation of their inhibitory actions on voltage-gated sodium channels, and antiseizure and antinociception activities and comparison with lacosamide and safinamide.

    Science.gov (United States)

    Park, Ki Duk; Yang, Xiao-Fang; Dustrude, Erik T; Wang, Yuying; Ripsch, Matthew S; White, Fletcher A; Khanna, Rajesh; Kohn, Harold

    2015-02-18

    The functionalized amino acid, lacosamide ((R)-2), and the α-aminoamide, safinamide ((S)-3), are neurological agents that have been extensively investigated and have displayed potent anticonvulsant activities in seizure models. Both compounds have been reported to modulate voltage-gated sodium channel activity. We have prepared a series of chimeric compounds, (R)-7-(R)-10, by merging key structural units in these two clinical agents, and then compared their activities with (R)-2 and (S)-3. Compounds were assessed for their ability to alter sodium channel kinetics for inactivation, frequency (use)-dependence, and steady-state activation and fast inactivation. We report that chimeric compounds (R)-7-(R)-10 in catecholamine A-differentiated (CAD) cells and embryonic rat cortical neurons robustly enhanced sodium channel inactivation at concentrations far lower than those required for (R)-2 and (S)-3, and that (R)-9 and (R)-10, unlike (R)-2 and (S)-3, produce sodium channel frequency (use)-dependence at low micromolar concentrations. We further show that (R)-7-(R)-10 displayed excellent anticonvulsant activities and pain-attenuating properties in the animal formalin model. Of these compounds, only (R)-7 reversed mechanical hypersensitivity in the tibial-nerve injury model for neuropathic pain in rats.

  11. Tennis playing is related to psychomotor speed in older drivers.

    Science.gov (United States)

    Marmeleira, José; Melo, Filipe; Tlemcani, Mouhaydine; Fernandes, Jorge

    2013-10-01

    The study investigated the association of tennis playing and running with the psychomotor speed of older drivers. Thirty-six active male drivers (M age = 63.2 yr.) participated. A battery of four on-the road driving tests was performed by tennis players, runners, and a control group. Measures of simple and choice reaction time, movement time, and response time were collected under single- and dual-task conditions. A composite driving score was calculated from reaction time measures of all driving tasks to reflect a general drivers' psychomotor speed. Statistically significant differences between groups were found in a braking task; tennis players performed significantly better than controls in simple reaction time and response time. The composite driving score also differed between groups, and tennis players had better results than controls. Regular participation in tennis was related to psychomotor speed of older drivers.

  12. Examination of perceptions (intensity, seat comfort, effort) and reaction times (brake and accelerator) during low-frequency vibration in x- or y-direction and biaxial ( xy-) vibration of driver seats with activated and deactivated suspension

    Science.gov (United States)

    Schust, Marianne; Blüthner, Ralph; Seidel, Helmut

    2006-12-01

    The optimal design of driver seats with horizontal suspension requires knowledge of human response with respect to the perception of the vibration intensity and seat comfort or of the performance in motor tasks. In an experimental study, 12 male volunteers (body mass 59-97.3 kg) were exposed to whole body vibrations in isolated x- or y-direction (three levels of magnitude) and biaxial xy-direction (combination of the x- and y-exposures on level two) sitting on a driver seat. The suspensions in x- and y-directions were randomly locked or unlocked. A brake and an accelerator foot pedal had to be pressed on demand as fast as possible. The perceptions of the vibration intensity, the seat comfort and the effort to carry out the motor task were judged by cross modality matching (modality: length of a line). The intensity judgements significantly increased with raising vibration magnitude. They were significantly higher for locked suspension. With only some exceptions, the judgements of the seat comfort decreased significantly with increasing magnitude, locked suspension and time. The effort judgements significantly increased with raising magnitude and time and revealed a tendency towards a lower effort with activated suspension. The reaction times showed no significant influences of vibration magnitude, suspension or time, but higher demands seemed to be compensated by enhanced effort. The w d-weighting did not adequately reflect the perceptions for the frequency spectra applied in this study in the x-axis. A modified 'overall vibration total value' determined from the non-weighted accelerations instead of the weighted ones (ISO 2631-1, Article 8.2.3) corresponded with the subjective judgements in case of exposure in x- and xy-directions. A clear definition of 'comfort' or 'discomfort' or the use of 'intensity' instead of these terms is recommendable.

  13. Driver style and driver skills – clustering drivers differing in their potential danger in traffic

    DEFF Research Database (Denmark)

    Martinussen, Laila Marianne; Møller, Mette; Prato, Carlo Giacomo

    and the DSI. Moreover, the joint use of the two instruments was applied to identify sub-groups of drivers that differ in their potential danger in traffic, as well as to test for heterogeneity across the population, namely whether the sub-groups of drivers differed in characteristics such as age, gender......, annual mileage and accident involvement. 3908 drivers aged 18–84 participated in the survey. The results suggested that the drivers have good insight into their own driving ability, as the driving skill level mirrored the frequency of aberrant driving behaviors. K-means cluster analysis revealed four...... distinct clusters that differed in the frequency of aberrant driving behavior and driving skills, as well as individual characteristics and driving related factors such as annual mileage, accident frequency and number of tickets and fines. Thus, two sub-groups were identified as more unsafe than the two...

  14. Reversible logic gates on Physarum Polycephalum

    Energy Technology Data Exchange (ETDEWEB)

    Schumann, Andrew [University of Information Technology and Management, Sucharskiego 2, Rzeszow, 35-225 (Poland)

    2015-03-10

    In this paper, we consider possibilities how to implement asynchronous sequential logic gates and quantum-style reversible logic gates on Physarum polycephalum motions. We show that in asynchronous sequential logic gates we can erase information because of uncertainty in the direction of plasmodium propagation. Therefore quantum-style reversible logic gates are more preferable for designing logic circuits on Physarum polycephalum.

  15. Demonstration of a Quantum Nondemolition Sum Gate

    DEFF Research Database (Denmark)

    Yoshikawa, J.; Miwa, Y.; Huck, Alexander;

    2008-01-01

    The sum gate is the canonical two-mode gate for universal quantum computation based on continuous quantum variables. It represents the natural analogue to a qubit C-NOT gate. In addition, the continuous-variable gate describes a quantum nondemolition (QND) interaction between the quadrature compo...

  16. Locomotor diseases among male long-haul truck drivers and other professional drivers

    DEFF Research Database (Denmark)

    Jensen, Anker; Kaerlev, Linda; Tüchsen, Finn

    2007-01-01

    -249) and for other truck drivers (SHR: 130, 95% CI: 108-156) compared to bus drivers (SHR: 110, 95% CI: 79-149). All drivers had high SHR for lesions of the ulnar nerve (SHR: 159, 95% CI: 119-207), especially bus drivers (SHR: 197, 95% CI: 116-311). Long-haul truck drivers had high SHRs for synovitis and bursitis...

  17. Locomotor diseases among male long-haul truck drivers and other professional drivers

    DEFF Research Database (Denmark)

    Jensen, Anker; Kaerlev, Linda; Tüchsen, Finn

    2007-01-01

    -249) and for other truck drivers (SHR: 130, 95% CI: 108-156) compared to bus drivers (SHR: 110, 95% CI: 79-149). All drivers had high SHR for lesions of the ulnar nerve (SHR: 159, 95% CI: 119-207), especially bus drivers (SHR: 197, 95% CI: 116-311). Long-haul truck drivers had high SHRs for synovitis and bursitis...

  18. Randomized benchmarking of multiqubit gates.

    Science.gov (United States)

    Gaebler, J P; Meier, A M; Tan, T R; Bowler, R; Lin, Y; Hanneke, D; Jost, J D; Home, J P; Knill, E; Leibfried, D; Wineland, D J

    2012-06-29

    We describe an extension of single-qubit gate randomized benchmarking that measures the error of multiqubit gates in a quantum information processor. This platform-independent protocol evaluates the performance of Clifford unitaries, which form a basis of fault-tolerant quantum computing. We implemented the benchmarking protocol with trapped ions and found an error per random two-qubit Clifford unitary of 0.162±0.008, thus setting the first benchmark for such unitaries. By implementing a second set of sequences with an extra two-qubit phase gate inserted after each step, we extracted an error per phase gate of 0.069±0.017. We conducted these experiments with transported, sympathetically cooled ions in a multizone Paul trap-a system that can in principle be scaled to larger numbers of ions.

  19. Bill Gates vil redde Folkeskolen

    DEFF Research Database (Denmark)

    Fejerskov, Adam Moe

    2014-01-01

    Det amerikanske uddannelsessystem bliver for tiden udsat for hård kritik, ledt an af Microsoft stifteren Bill Gates. Gates har indtil videre brugt 3 mia. kroner på at skabe opbakning til tiltag som præstationslønning af lærere og strømlining af pensum på tværs af alle skoler i landet......Det amerikanske uddannelsessystem bliver for tiden udsat for hård kritik, ledt an af Microsoft stifteren Bill Gates. Gates har indtil videre brugt 3 mia. kroner på at skabe opbakning til tiltag som præstationslønning af lærere og strømlining af pensum på tværs af alle skoler i landet...

  20. Voltage-gated sodium channel Nav1.7 maintains the membrane potential and regulates the activation and chemokine-induced migration of a monocyte-derived dendritic cell subset.

    Science.gov (United States)

    Kis-Toth, Katalin; Hajdu, Peter; Bacskai, Ildiko; Szilagyi, Orsolya; Papp, Ferenc; Szanto, Attila; Posta, Edit; Gogolak, Peter; Panyi, Gyorgy; Rajnavolgyi, Eva

    2011-08-01

    Expression of CD1a protein defines a human dendritic cell (DC) subset with unique functional activities. We aimed to study the expression of the Nav1.7 sodium channel and the functional consequences of its activity in CD1a(-) and CD1a(+) DC. Single-cell electrophysiology (patch-clamp) and quantitative PCR experiments performed on sorted CD1a(-) and CD1a(+) immature DC (IDC) showed that the frequency of cells expressing Na(+) current, current density, and the relative expression of the SCN9A gene encoding Nav1.7 were significantly higher in CD1a(+) cells than in their CD1a(-) counterparts. The activity of Nav1.7 results in a depolarized resting membrane potential (-8.7 ± 1.5 mV) in CD1a(+) IDC as compared with CD1a(-) cells lacking Nav1.7 (-47 ± 6.2 mV). Stimulation of DC by inflammatory signals or by increased intracellular Ca(2+) levels resulted in reduced Nav1.7 expression. Silencing of the SCN9A gene shifted the membrane potential to a hyperpolarizing direction in CD1a(+) IDC, resulting in decreased cell migration, whereas pharmacological inhibition of Nav1.7 by tetrodotoxin sensitized the cells for activation signals. Fine-tuning of IDC functions by a voltage-gated sodium channel emerges as a new regulatory mechanism modulating the migration and cytokine responses of these DC subsets.

  1. Bill Gates vil redde Folkeskolen

    DEFF Research Database (Denmark)

    Fejerskov, Adam Moe

    2014-01-01

    Det amerikanske uddannelsessystem bliver for tiden udsat for hård kritik, ledt an af Microsoft stifteren Bill Gates. Gates har indtil videre brugt 3 mia. kroner på at skabe opbakning til tiltag som præstationslønning af lærere og strømlining af pensum på tværs af alle skoler i landet...

  2. Quantum gates with topological phases

    CERN Document Server

    Ionicioiu, R

    2003-01-01

    We investigate two models for performing topological quantum gates with the Aharonov-Bohm (AB) and Aharonov-Casher (AC) effects. Topological one- and two-qubit Abelian phases can be enacted with the AB effect using charge qubits, whereas the AC effect can be used to perform all single-qubit gates (Abelian and non-Abelian) for spin qubits. Possible experimental setups suitable for a solid state implementation are briefly discussed.

  3. Gating a ferromagnetic semiconductor

    Science.gov (United States)

    Bove, A.; Altomare, F.; Kundtz, N.; Chang, A. M.; Cho, Y. J.; Liu, X.; Furdyna, J.

    2007-03-01

    Ferromagnetic semiconductors have the potential of revolutionizing the way current electronic devices work: more so, because they are compatible with current fabrication lines and can easily be integrated with today's technology. Particular interest lies in III-V Diluted Magnetic Semiconductor (DMS), where the ferromagnetism is hole-mediated and the Curie temperature can therefore be tuned by changing the concentration of free carriers. In these systems, most of the effort is currently applied toward the fabrication of devices working at room-temperature: this implies high carrier density accompanied by low mobility and short mean free path. We will report our results for a ferromagnetic 2DHG system with low carrier density (˜3.4E12 cm-2) and mobility (˜ 1000 cm^2/(Vs)), and we will discuss the effects of local gating in light of possible applications to the fabrication of ferromagnetic quantum dots. T. Dietl et al., Phys. Rev. B 63, 195205 (2001). H. Ohno et al., Nature 408, 944 (2000)

  4. Hydrophobic plug functions as a gate in voltage-gated proton channels.

    Science.gov (United States)

    Chamberlin, Adam; Qiu, Feng; Rebolledo, Santiago; Wang, Yibo; Noskov, Sergei Y; Larsson, H Peter

    2014-01-14

    Voltage-gated proton (Hv1) channels play important roles in the respiratory burst, in pH regulation, in spermatozoa, in apoptosis, and in cancer metastasis. Unlike other voltage-gated cation channels, the Hv1 channel lacks a centrally located pore formed by the assembly of subunits. Instead, the proton permeation pathway in the Hv1 channel is within the voltage-sensing domain of each subunit. The gating mechanism of this pathway is still unclear. Mutagenic and fluorescence studies suggest that the fourth transmembrane (TM) segment (S4) functions as a voltage sensor and that there is an outward movement of S4 during channel activation. Using thermodynamic mutant cycle analysis, we find that the conserved positively charged residues in S4 are stabilized by countercharges in the other TM segments both in the closed and open states. We constructed models of both the closed and open states of Hv1 channels that are consistent with the mutant cycle analysis. These structural models suggest that electrostatic interactions between TM segments in the closed state pull hydrophobic residues together to form a hydrophobic plug in the center of the voltage-sensing domain. Outward S4 movement during channel activation induces conformational changes that remove this hydrophobic plug and instead insert protonatable residues in the center of the channel that, together with water molecules, can form a hydrogen bond chain across the channel for proton permeation. This suggests that salt bridge networks and the hydrophobic plug function as the gate in Hv1 channels and that outward movement of S4 leads to the opening of this gate.

  5. Latest design of gate valves

    Energy Technology Data Exchange (ETDEWEB)

    Kurzhofer, U.; Stolte, J.; Weyand, M.

    1996-12-01

    Babcock Sempell, one of the most important valve manufacturers in Europe, has delivered valves for the nuclear power industry since the beginning of the peaceful application of nuclear power in the 1960s. The latest innovation by Babcock Sempell is a gate valve that meets all recent technical requirements of the nuclear power technology. At the moment in the United States, Germany, Sweden, and many other countries, motor-operated gate and globe valves are judged very critically. Besides the absolute control of the so-called {open_quotes}trip failure,{close_quotes} the integrity of all valve parts submitted to operational forces must be maintained. In case of failure of the limit and torque switches, all valve designs have been tested with respect to the quality of guidance of the gate. The guidances (i.e., guides) shall avoid a tilting of the gate during the closing procedure. The gate valve newly designed by Babcock Sempell fulfills all these characteristic criteria. In addition, the valve has cobalt-free seat hardfacing, the suitability of which has been proven by friction tests as well as full-scale blowdown tests at the GAP of Siemens in Karlstein, West Germany. Babcock Sempell was to deliver more than 30 gate valves of this type for 5 Swedish nuclear power stations by autumn 1995. In the presentation, the author will report on the testing performed, qualifications, and sizing criteria which led to the new technical design.

  6. [Drivers of advanced age in traffic accidents].

    Science.gov (United States)

    Bilban, Marjan

    2002-12-01

    The elderly are vulnerable and potentially unpredictable active participants in traffic who deserve special attention. Longer life expectancy entails a greater number of senior drivers, that is, persons with various health problems and difficulties accompanying old age. At the turn of the millennium, the share of population aged 65 or more in Slovenia was around 13%, and in 25 years it will be near as much as 19%. The share of drivers from this age group was 28% a year ago, and it is expected to reach about 54%. Numerous studies have shown that there are many differences in driving attitude between the young and the elderly. The young are by large active victims, and their main offense and cause of accident is speeding, while the elderly are more passive and their main offense is ignoring and enforcing the right of way. This paper focuses on the differences in the occurrence and type of injuries between the young and the elderly drivers, based on an analysis of all road accidents in Slovenia in the period between 1998-2000. Older people (over 65) caused only 4.7% of all road accidents (16.7% of all accidents involving pedestrians, 11.5% of all involving cyclists, 2.7% involving motorcyclists and 5% of all accidents involving car drivers). Of all accidents, 89.3% were without injuries, and the fatal outcome was registered in 0.4% accidents. Among the elderly (65-74 years of age), however, this share was 1%, and rising to 2.7% with the age 75 and above. By calculating the weight index, which discriminates between minor and severe injuries, and the fatal outcome, it was established that age groups 65-74 and > or = 75 cause three and five times greater damage, respectively than age groups from 18 to 54 years. With years, psychophysical changes lead to a drop in driving ability, which in turn increases the risk of road accidents. It is true that elderly people cause less traffic accidents (and also drive less) than the young, but when they are involved in an accident

  7. Sexual behavior among truck drivers.

    Science.gov (United States)

    Singh, Rajiv Kumar; Joshi, Hari Shankar

    2012-01-01

    A cross-sectional study was conducted on Lucknow highway in Bareilly district of Uttar Pradesh to study the knowledge of truck drivers about HIV transmission and prevention and to study the sexual behaviour of these drivers with reference to HIV/AIDS. Age, marital status, education, income, drinking alcohol, length of stay away from home, knowledge about transmission and prevention of HIV, and HIV-prone behavior of truck drivers were studied. Chi-square, mean, and SD were calculated. In all, 289 (97.6%) drivers had heard about HIV/AIDS. Only 242 (81.8%) were aware of HIV transmission by heterosexual route. Misconceptions such as HIV transmission by mosquito bites, living in same room, shaking hands, and sharing food were found. Out of 174 (58.8%) who visited Commercial Sex Workers (CSW), 146 (83.9%) used a condom. 38 (12.8%) visited more than 5 CSW in the last 3 months. Time away from home on the road, marital status, alcohol use, and income class were associated with visiting CSW. High-risk behavior was established in the study population. Safe sex and use of condoms need to be promoted among the truck drivers and better condom availability needs to be assured on highways.

  8. SEMiX and SKYPER an Intelligent IGBT Module with Adaptable Driver

    Institute of Scientific and Technical Information of China (English)

    MartinFreyberg; MarkusHermwille; Uk-SongHong; JensLi

    2004-01-01

    Modern power converter designs need compact IGBT modules with simple interfaces for costefficient power solutions.Low overall height.separate AC and DC terminals on eaeh side,driver access on top are recent market requirements for modern power nmdules.This leads to the birth of SEMiX-a module platform with the right answer to these requirements.Moreover.this paper highlights also a new driver solution for modules-SKYPER-a simple add-on gate driver with basic driving and protection funetions.Its adaptation to modules-in this article through an example with SEMiX-is tested suecessfully.SEMiX and SKYPER behave like an IPM but offer more flexibilitv to control switching characteristics.presenting a convenient building block for modular inverter solutions.

  9. MoS2 based dual input logic AND gate

    Science.gov (United States)

    Martinez, Luis M.; Pinto, Nicholas J.; Naylor, Carl H.; Johnson, A. T. Charlie

    2016-12-01

    Crystalline monolayers of CVD MoS2 are used as the active semiconducting channel in a split-gate field effect transistor. The device demonstrates logic AND functionality that is controlled by independently addressing each gate terminal with ±10V. When +10V was simultaneously applied to both gates, the device was conductive (ON), while any other combination of gate voltages rendered the device resistive (OFF). The ON/OFF ratio of the device was ˜ 35 and the charge mobility using silicon nitride as the gate dielectric was 1.2cm2/V-s and 0.1cm2/V-s in the ON and OFF states respectively. Clear discrimination between the two states was observed when a simple circuit containing a load resistor was used to test the device logic AND functionality at 10Hz. One advantage is that split gate technology can reduce the number of devices required in complex circuits, leading to compact electronics and large scale integration based on intrinsic 2-D semiconducting materials.

  10. Gate tunable graphene-silicon Ohmic/Schottky contacts

    Science.gov (United States)

    Chen, Chun-Chung; Chang, Chia-Chi; Li, Zhen; Levi, A. F. J.; Cronin, Stephen B.

    2012-11-01

    We show that the I-V characteristics of graphene-silicon junctions can be actively tuned from rectifying to Ohmic behavior by electrostatically doping the graphene with a polymer electrolyte gate. Under zero applied gate voltage, we observe rectifying I-V characteristics, demonstrating the formation of a Schottky junction at the graphene-silicon interface. Through appropriate gating, the Fermi energy of the graphene can be varied to match the conduction or valence band of silicon, thus forming Ohmic contacts with both n- and p-type silicon. Over the applied gate voltage range, the low bias conductance can be varied by more than three orders of magnitude. By varying the top gate voltage from -4 to +4 V, the Fermi energy of the graphene is shifted between -3.78 and -5.47 eV; a shift of ±0.85 eV from the charge neutrality point. Since the conduction and valence bands of the underlying silicon substrate lie within this range, at -4.01 and -5.13 eV, the Schottky barrier height and depletion width can be decreased to zero for both n- and p-type silicon under the appropriate top gating conditions. I-V characteristics taken under illumination show that the photo-induced current can be increased or decreased based on the graphene-silicon work function difference.

  11. Identifying Cancer Driver Genes Using Replication-Incompetent Retroviral Vectors

    Directory of Open Access Journals (Sweden)

    Victor M. Bii

    2016-10-01

    Full Text Available Identifying novel genes that drive tumor metastasis and drug resistance has significant potential to improve patient outcomes. High-throughput sequencing approaches have identified cancer genes, but distinguishing driver genes from passengers remains challenging. Insertional mutagenesis screens using replication-incompetent retroviral vectors have emerged as a powerful tool to identify cancer genes. Unlike replicating retroviruses and transposons, replication-incompetent retroviral vectors lack additional mutagenesis events that can complicate the identification of driver mutations from passenger mutations. They can also be used for almost any human cancer due to the broad tropism of the vectors. Replication-incompetent retroviral vectors have the ability to dysregulate nearby cancer genes via several mechanisms including enhancer-mediated activation of gene promoters. The integrated provirus acts as a unique molecular tag for nearby candidate driver genes which can be rapidly identified using well established methods that utilize next generation sequencing and bioinformatics programs. Recently, retroviral vector screens have been used to efficiently identify candidate driver genes in prostate, breast, liver and pancreatic cancers. Validated driver genes can be potential therapeutic targets and biomarkers. In this review, we describe the emergence of retroviral insertional mutagenesis screens using replication-incompetent retroviral vectors as a novel tool to identify cancer driver genes in different cancer types.

  12. Key drivers of airline loyalty

    Science.gov (United States)

    Dolnicar, Sara; Grabler, Klaus; Grün, Bettina; Kulnig, Anna

    2011-01-01

    This study investigates drivers of airline loyalty. It contributes to the body of knowledge in the area by investigating loyalty for a number of a priori market segments identified by airline management and by using a method which accounts for the multi-step nature of the airline choice process. The study is based on responses from 687 passengers. Results indicate that, at aggregate level, frequent flyer membership, price, the status of being a national carrier and the reputation of the airline as perceived by friends are the variables which best discriminate between travellers loyal to the airline and those who are not. Differences in drivers of airline loyalty for a number of segments were identified. For example, loyalty programs play a key role for business travellers whereas airline loyalty of leisure travellers is difficult to trace back to single factors. For none of the calculated models satisfaction emerged as a key driver of airline loyalty. PMID:27064618

  13. Key drivers of airline loyalty.

    Science.gov (United States)

    Dolnicar, Sara; Grabler, Klaus; Grün, Bettina; Kulnig, Anna

    2011-10-01

    This study investigates drivers of airline loyalty. It contributes to the body of knowledge in the area by investigating loyalty for a number of a priori market segments identified by airline management and by using a method which accounts for the multi-step nature of the airline choice process. The study is based on responses from 687 passengers. Results indicate that, at aggregate level, frequent flyer membership, price, the status of being a national carrier and the reputation of the airline as perceived by friends are the variables which best discriminate between travellers loyal to the airline and those who are not. Differences in drivers of airline loyalty for a number of segments were identified. For example, loyalty programs play a key role for business travellers whereas airline loyalty of leisure travellers is difficult to trace back to single factors. For none of the calculated models satisfaction emerged as a key driver of airline loyalty.

  14. Voltage-gated proton channel is expressed on phagosomes.

    Science.gov (United States)

    Okochi, Yoshifumi; Sasaki, Mari; Iwasaki, Hirohide; Okamura, Yasushi

    2009-05-01

    Voltage-gated proton channel has been suggested to help NADPH oxidase activity during respiratory burst of phagocytes through its activities of compensating charge imbalance and regulation of pH. In phagocytes, robust production of reactive oxygen species occurs in closed membrane compartments, which are called phagosomes. However, direct evidence for the presence of voltage-gated proton channels in phagosome has been lacking. In this study, the expression of voltage-gated proton channels was studied by Western blot with the antibody specific to the voltage-sensor domain protein, VSOP/Hv1, that has recently been identified as the molecular correlate for the voltage-gated proton channel. Phagosomal membranes of neutrophils contain VSOP/Hv1 in accordance with subunits of NADPH oxidases, gp91, p22, p47 and p67. Superoxide anion production upon PMA activation was significantly reduced in neutrophils from VSOP/Hv1 knockout mice. These are consistent with the idea that voltage-gated proton channels help NADPH oxidase in phagocytes to produce reactive oxygen species.

  15. A Literature Unit for "Dragon's Gate" by Laurence Yep.

    Science.gov (United States)

    Thomas-Vallens, Mary

    Intended as a an aid to classroom teachers, this 52-page handbook presents a literature unit based on the children and young people's book, "Dragon's Gate" by Laurence Yep. It begins with sample lesson plans, pre-reading activities, author information, a book summary, vocabulary lists and suggested vocabulary activities. Next, chapters…

  16. A Literature Unit for "Dragon's Gate" by Laurence Yep.

    Science.gov (United States)

    Thomas-Vallens, Mary

    Intended as a an aid to classroom teachers, this 52-page handbook presents a literature unit based on the children and young people's book, "Dragon's Gate" by Laurence Yep. It begins with sample lesson plans, pre-reading activities, author information, a book summary, vocabulary lists and suggested vocabulary activities. Next, chapters…

  17. Detailed profiling of anti-desmoglein autoantibodies identifies anti-Dsg1 reactivity as a key driver of disease activity and clinical expression in pemphigus vulgaris.

    Science.gov (United States)

    Naseer, S Y; Seiffert-Sinha, K; Sinha, A A

    2015-06-01

    With their near-universal presence in patients and ease of clinical measurement, anti-desmoglein (Dsg) antibodies serve as primary candidates for creating prognostic tools in Pemphigus vulgaris (PV). Although the desmoglein compensation hypothesis postulates a clear relationship between anti-Dsg autoantibodies and clinical phenotype in PV, recent studies have questioned the fidelity of this hypothesis as a predictor of lesion morphology. Moreover, few studies address the association of anti-Dsg antibodies to other clinical parameters such as disease phase and age at onset. Using the largest patient repository to date in PV, we present a detailed analysis of anti-desmoglein antibody profiles across a comprehensive range of dynamic (disease phase, therapy, lesion morphology) and temporal (disease duration, age at sampling, age at onset) clinical parameters. Our data highlight the non-traditional but key role of anti-Dsg1 levels in tracking disease activity. We show that declining anti-Dsg1 levels may predict progression from active phase to early remission and long-term maintenance of remission, regardless of lesion morphology. In contrast, many remittent patients have elevated levels of anti-Dsg3 without lesional activity. Furthermore, we describe a unique subset of remittent patients that develop chronic transient lesions (lasting <1 week) in the setting of elevated anti-Dsg3 levels but do not meet the consensus criteria for active phase. Re-classification of patients with transient lesions as "active" may shed new light on pathophysiological processes underlying cycles of blister formation and rapid spontaneous healing in PV. Additionally, we provide evidence for the potential attenuation of the immune response with prolonged disease duration. Our data fit into the broader effort of immunoprofiling to promote data-informed decision-making regarding diagnosis, prognosis and treatment of complex diseases.

  18. 超极化活化环核苷酸门孔通道与心脏生物起搏器(第二部分)%Hyperpolarization-activated Cyclic nucleotide-gated Channel and Cardiac Biological Pacemaker: Part Ⅱ

    Institute of Scientific and Technical Information of China (English)

    萧永福

    2005-01-01

    Abstract Hyperpolarization-activated cyclic-nucleotide-gated (HCN) channels in the heart modulate cardiac automaticity via the hyperpolarization-activated cation current (named If, Ih, or Iq ).Recent studies have unveiled the molecular identity of HCN (HCN14) channels. HCN isoforms are unevenly expressed in the heart, even in the sinoatrial node. Features of HCN currents have been characterized in cardiac and other types of cells or in cell lines transfected with the HCN isoforms. The factors modulating Ih and the physiological significance of HCN channels in the heart have been extensively investigated in recent years. The hypothesis for transplanting and/or creating biological pacemakers to replace diseased sinoatrial and/or atrioventricular nodes has been postulated and tested in animal models. Local overexpression of HCN2 channels in the left atrium or in the left conductive bundle branch of the left ventricle via gene delivery induced significant Ih and escape rhythms during vagal stimulation in canines. In addition, implantation of human mesenchymal stem cells with overexpression of HCN2 channels to the canine left ventricular wall was associated with formation of spontaneous escape rhythms of left-sided origin during vagal-stimulation-induced sinus arrest. This preliminary data suggest that the use of HCN channels may hold great promise in the development of biological pacemakers.

  19. MODELING DRIVER BEHAVIOR IN THE DRIVING OF THEIR MOTOR VEHICLE

    Directory of Open Access Journals (Sweden)

    A. V. Skrypnikov

    2015-01-01

    Full Text Available The article holds the gradual formation of images and actions of the driver. As outlined the author's arguments based on the following assumptions: We consider the motion of the mass, mass-produced currently by the domestic industry of automobiles; considered the motion of single cars as the most common and most dangerous cases, allowing to evaluate the influence of parameters on the road driving mode "pure"; drivers tend to reduce travel times and therefore move with the maximum possible speed; drivers choose speed, visually estimating lying in front of part of the way and given the speed at the time of this evaluation; driver behavior, ceteris paribus determined the influence of visibility limitations and conditions visual perception; considered the motion on the ascent and descent, but the determining factor is the direction of descent. Set of operations, branches off the driver, can be represented as a multi-level system comprising three main groups of psycho-physiological processes, activities analyzers (perception of information; the work of the central nervous system (processing and storage; effective activity (responses to the implementation of the decision. On the basis of the received information in human consciousness formed images of the environment, the totality of which is an information model of the object. Comparing it with the standards (memory engrams, the driver generates the mo st appropriate in the circumstances set of actions. Implementation of the decision is the final stage of human response to the external environment and is expressed in the change of the degree of use of traction engine or braking force; change the steering angle as that does not affect the speed of motion, the algorithm of the driver is not taken into account. Analysis of the schemes of algorithms allows to obtain quantitative characteristics of the vehicle: stereotyped figures, logical complexity.

  20. New opening hours of the gates

    CERN Multimedia

    GS Department

    2009-01-01

    Please note the new opening hours of the gates as well as the intersites tunnel from the 19 May 2009: GATE A 7h - 19h GATE B 24h/24 GATE C 7h - 9h\t17h - 19h GATE D 8h - 12h\t13h - 16h GATE E 7h - 9h\t17h - 19h Prévessin 24h/24 The intersites tunnel will be opened from 7h30 to 18h non stop. GS-SEM Group Infrastructure and General Services Department

  1. TwinDrivers: Semi-Automatic Derivation of Fast and Safe Hypervisor Network Drivers from Guest OS Drivers

    OpenAIRE

    2009-01-01

    In a virtualized environment, device drivers are often run inside a virtual machine (VM) rather than in the hypervisor. Doing so protects the hypervisor from bugs in the driver, and also allows the reuse of the device driver and its support infrastructure in the VM. Unfortunately, this approach results in poor performance for I/O intensive devices such as network cards. The alternative approach is to run device drivers directly in the hypervisor. Although this approach results in better perfo...

  2. Fuel-Cell Drivers Wanted

    Science.gov (United States)

    Clark, Todd; Jones, Rick

    2004-01-01

    While the political climate seems favorable for the development of fuel-cell vehicles for personal transportation, the market's demand may not be so favorable. Nonetheless, middle level students will be the next generation of drivers and voters, and they need to be able to make informed decisions regarding the nation's energy and transportation…

  3. Drivers and Limits for Transport

    DEFF Research Database (Denmark)

    Kristensen, Niels Buus; Nielsen, Thomas A. Sick; Gudmundsson, Henrik;

    This report summarizes key outcomes of the study ’Drivers and Limits’ that was supported for the period 2009-2013 by a research grant from the Danish Strategic Research Council. The project investigated - for the empirical context of Denmark - key driving forces behind transport growth, as well...

  4. SLEEPINESS AMONG IRANIAN LORRY DRIVERS

    Directory of Open Access Journals (Sweden)

    K. Sadeghniiat Y. Labbafinejad

    2007-06-01

    Full Text Available Excessive daytime sleepiness (EDS denotes a propensity to doze off or fall asleep unintentionally during the day, particularly in passive situations. There is cumulative evidence pointing to an association between sleepiness and probability of involvement in motor vehicle crashes. This study was designed to determine the prevalence of sleepiness in a group of Iranian lorry drivers and its association with accidents. A cross-sectional study was carried out in lorry drivers of Tehran goods transportation terminal in 2005. This study used a questionnaire and the Epworth Sleepiness Scale (ESS. The questionnaire included questions regarding demographic features, professional data, sleep habits and excessive daytime sleepiness. A total of 386 male drivers, aged 43.23 ± 9.72 years were included in the study. ESS was higher than 10 points in 9.1% of the interviewees; 50.8% never have driven drowsy, although 36% rarely, 7.3% half of the times, 4.9% almost always and 1% always have driven drowsy. Logistic regression analysis indicated that EDS, age and job satisfaction were associated with an increased risk of accidents. Sleepiness is a prevailing symptom in lorry drivers and is probably related to accidents.

  5. Ionic thermoelectric gating organic transistors

    Science.gov (United States)

    Zhao, Dan; Fabiano, Simone; Berggren, Magnus; Crispin, Xavier

    2017-01-01

    Temperature is one of the most important environmental stimuli to record and amplify. While traditional thermoelectric materials are attractive for temperature/heat flow sensing applications, their sensitivity is limited by their low Seebeck coefficient (∼100 μV K−1). Here we take advantage of the large ionic thermoelectric Seebeck coefficient found in polymer electrolytes (∼10,000 μV K−1) to introduce the concept of ionic thermoelectric gating a low-voltage organic transistor. The temperature sensing amplification of such ionic thermoelectric-gated devices is thousands of times superior to that of a single thermoelectric leg in traditional thermopiles. This suggests that ionic thermoelectric sensors offer a way to go beyond the limitations of traditional thermopiles and pyroelectric detectors. These findings pave the way for new infrared-gated electronic circuits with potential applications in photonics, thermography and electronic-skins. PMID:28139738

  6. Ionic thermoelectric gating organic transistors

    Science.gov (United States)

    Zhao, Dan; Fabiano, Simone; Berggren, Magnus; Crispin, Xavier

    2017-01-01

    Temperature is one of the most important environmental stimuli to record and amplify. While traditional thermoelectric materials are attractive for temperature/heat flow sensing applications, their sensitivity is limited by their low Seebeck coefficient (~100 μV K-1). Here we take advantage of the large ionic thermoelectric Seebeck coefficient found in polymer electrolytes (~10,000 μV K-1) to introduce the concept of ionic thermoelectric gating a low-voltage organic transistor. The temperature sensing amplification of such ionic thermoelectric-gated devices is thousands of times superior to that of a single thermoelectric leg in traditional thermopiles. This suggests that ionic thermoelectric sensors offer a way to go beyond the limitations of traditional thermopiles and pyroelectric detectors. These findings pave the way for new infrared-gated electronic circuits with potential applications in photonics, thermography and electronic-skins.

  7. Pixel-Level Digital-to-Analog Conversion Scheme with Compensation of Thin-Film-Transistor Variations for Compact Integrated Data Drivers of Active Matrix Organic Light Emitting Diodes

    Science.gov (United States)

    Kim, Tae-Wook; Park, Sang-Gyu; Choi, Byong-Deok

    2011-03-01

    The previous pixel-level digital-to-analog-conversion (DAC) scheme that implements a part of a DAC in a pixel circuit turned out to be very efficient for reducing the peripheral area of an integrated data driver fabricated with low-temperature polycrystalline silicon thin-film transistors (LTPS TFTs). However, how the pixel-level DAC can be compatible with the existing pixel circuits including compensation schemes of TFT variations and IR drops on supply rails, which is of primary importance for active matrix organic light emitting diodes (AMOLEDs) is an issue in this scheme, because LTPS TFTs suffer from random variations in their characteristics. In this paper, we show that the pixel-level DAC scheme can be successfully used with the previous compensation schemes by giving two examples of voltage- and current-programming pixels. The previous pixel-level DAC schemes require additional two TFTs and one capacitor, but for these newly proposed pixel circuits, the overhead is no more than two TFTs by utilizing the already existing capacitor. In addition, through a detailed analysis, it has been shown that the pixel-level DAC can be expanded to a 4-bit resolution, or be applied together with 1:2 demultiplexing driving for 6- to 8-in. diagonal XGA AMOLED display panels.

  8. Pixel-Level Digital-to-Analog Conversion Scheme for Compact Data Drivers of Active Matrix Organic Light-Emitting Diodes with Low-Temperature Polycrystalline Silicon Thin-Film Transistors

    Science.gov (United States)

    Tae-Wook Kim,; Byong-Deok Choi,

    2010-03-01

    This paper shows that a part of a digital-to-analog conversion (DAC) function can be included in a pixel circuit to save the circuit area of an integrated data driver fabricated with low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs). Because the pixel-level DAC can be constructed by two TFTs and one small capacitor, the pixel circuit does not become markedly complex. The design of an 8-bit DAC, which combines a 6-bit resistor-string-based DAC and a 2-bit pixel-level DAC for a 4-in. diagonal VGA format active matrix organic light-emitting diode (AMOLED), is shown in detail. In addition, analysis results are presented, revealing that the 8-bit DAC scheme including a 2-bit pixel-level DAC with 1:3 demultiplexing can be applied to very high video formats, such as XGA, for a 3 to 4-in. diagonal AMOLED. Even for a 9- to 12-in. diagonal AMOLED, the proposed scheme can still be applied to the XGA format, even though no demultiplexing is allowed. The total height of the proposed 8-bit DAC is approximately 960 μm, which is almost one-half of that of the previous 6-bit resistor-string-based DAC.

  9. An 8-bit Data Driving Scheme Based on Two-Step Digital-to-Analog Conversion for Integrated Data Drivers of Active-Matrix Organic Light-Emitting Diodes

    Science.gov (United States)

    Kim, Tae-Wook; Choi, Byong-Deok

    2012-03-01

    The two-step digital-to-analog conversion (DAC) scheme has been reported to be very area-efficient for thin-film transistor-liquid crystal display (TFT-LCD) data driver ICs, but it is not as well suited as it is for polycrystalline silicon (poly-Si) TFT integrated circuits. The charge redistribution in the two-step DAC process requires an operational amplifier in principle, which is most challenging for poly-Si TFT circuits. The proposed two-step DAC for active-matrix organic light-emitting diodes (AMOLEDs) makes the operational amplifier unnecessary by appropriately exploiting the preexisting capacitors in the pixel to compensate for the characteristic variations of TFTs. Moreover, the second-step DAC occurs at the same time as threshold voltage compensation, and it does not require additional time. By thoroughly analyzing area efficiency depending on the resolution decomposition between the first- and second-step DACs, we found that 5-bit coarse plus 3-bit fine DACs are best in terms of circuit area. When we designed a layout of the proposed 8-bit DAC on the basis of the 4 µm design rules, the DAC circuit area is no more than 72×637 µm2, which, to the best of our knowledge, is the most compact to date.

  10. Activation of Neck and Low-Back Muscles Is Reduced with the Use of a Neck Balance System Together with a Lumbar Support in Urban Drivers.

    Directory of Open Access Journals (Sweden)

    Federica Menotti

    Full Text Available Driving is associated with high activation of low-back and neck muscles due to the sitting position and perturbations imposed by the vehicle. The aim of this study was to investigate the use of a neck balance system together with a lumbar support on the activation of low-back and neck muscles during driving. Twelve healthy male subjects (age 32±6.71 years were asked to drive in two conditions: 1 with devices; 2 without devices. During vehicle accelerations and decelerations root mean square (RMS of surface electromyography (sEMG was recorded from the erector spinae, semispinalis capitis and sternocleidomastoid muscles and expressed as a percentage of maximal voluntary contraction (MVC. The pitch of the head was obtained by means of an inertial sensor placed on the subjects' head. A visual analog scale (VAS was used to assess the level of perceived comfort. RMS of the low back muscles was lower with than without devices during both acceleration and deceleration of the vehicle (1.40±0.93% vs 29 2.32±1.90% and 1.88±1.45% vs 2.91±2.33%, respectively, while RMS of neck extensor muscles was reduced only during acceleration (5.18±1.96% vs 5.91±2.16%. There were no differences between the two conditions in RMS of neck flexor muscles, the pitch of the head and the VAS score. The use of these two ergonomic devices is therefore effective in reducing the activation of low-back and neck muscles during driving with no changes in the level of perceived comfort, which is likely due to rebalancing weight on the neck and giving a neutral position to lumbar segments.

  11. Localizing a gate in CFTR.

    Science.gov (United States)

    Gao, Xiaolong; Hwang, Tzyh-Chang

    2015-02-24

    Experimental and computational studies have painted a picture of the chloride permeation pathway in cystic fibrosis transmembrane conductance regulator (CFTR) as a short narrow tunnel flanked by wider inner and outer vestibules. Although these studies also identified a number of transmembrane segments (TMs) as pore-lining, the exact location of CFTR's gate(s) remains unknown. Here, using a channel-permeant probe, [Au(CN)2](-), we provide evidence that CFTR bears a gate that coincides with the predicted narrow section of the pore defined as residues 338-341 in TM6. Specifically, cysteines introduced cytoplasmic to the narrow region (i.e., positions 344 in TM6 and 1148 in TM12) can be modified by intracellular [Au(CN)2](-) in both open and closed states, corroborating the conclusion that the internal vestibule does not harbor a gate. However, cysteines engineered to positions external to the presumed narrow region (e.g., 334, 335, and 337 in TM6) are all nonreactive toward cytoplasmic [Au(CN)2](-) in the absence of ATP, whereas they can be better accessed by extracellular [Au(CN)2](-) when the open probability is markedly reduced by introducing a second mutation, G1349D. As [Au(CN)2](-) and chloride ions share the same permeation pathway, these results imply a gate is situated between amino acid residues 337 and 344 along TM6, encompassing the very segment that may also serve as the selectivity filter for CFTR. The unique position of a gate in the middle of the ion translocation pathway diverges from those seen in ATP-binding cassette (ABC) transporters and thus distinguishes CFTR from other members of the ABC transporter family.

  12. Identification of spinal circuits transmitting and gating mechanical pain

    Science.gov (United States)

    Bourane, Steeve; Britz, Olivier; Padilla, Christopher; Garcia-Campmany, Lidia; Krashes, Michael; Knowlton, Wendy; Velasquez, Tomoko; Ren, Xiangyu; Ross, Sarah; Lowell, Bradford B.; Wang, Yun; Goulding, Martyn; Ma, Qiufu

    2014-01-01

    SUMMARY Pain processing in the spinal cord has been postulated to rely on nociceptive transmission (T) neurons receiving inputs from nociceptors and Aβ mechanoreceptors, with Aβ inputs gated through feed-forward activation of spinal inhibitory neurons (IN). Here we used intersectional genetic manipulations to identify these critical components of pain transduction. Marking and ablating six populations of spinal excitatory and inhibitory neurons, coupled with behavioral and electrophysiological analysis, showed that excitatory neurons expressing somatostatin (SOM) represent T-type cells, whose ablation causes loss of mechanical pain. Inhibitory neurons marked by the expression of dynorphin (Dyn) represent IN-type neurons, which are necessary to gate Aβ fibers from activating SOM+ neurons to evoke pain. Therefore, peripheral mechanical nociceptors and Aβ mechanoreceptors, together with spinal SOM+ excitatory and Dyn+ inhibitory neurons form a microcircuit that transmits and gates mechanical pain. PMID:25467445

  13. Driver ASICs for Advanced Deformable Mirrors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The overall goal of the SBIR program is to develop a new Application Specified Integrated Circuit (ASIC) driver to be used in driver electronics of a deformable...

  14. Anthropogenic Drivers of Ecosystem Change: an Overview

    Directory of Open Access Journals (Sweden)

    Gerald C. Nelson

    2006-12-01

    Full Text Available This paper provides an overview of what the Millennium Ecosystem Assessment (MA calls "indirect and direct drivers" of change in ecosystem services at a global level. The MA definition of a driver is any natural or human-induced factor that directly or indirectly causes a change in an ecosystem. A direct driver unequivocally influences ecosystem processes. An indirect driver operates more diffusely by altering one or more direct drivers. Global driving forces are categorized as demographic, economic, sociopolitical, cultural and religious, scientific and technological, and physical and biological. Drivers in all categories other than physical and biological are considered indirect. Important direct drivers include changes in climate, plant nutrient use, land conversion, and diseases and invasive species. This paper does not discuss natural drivers such as climate variability, extreme weather events, or volcanic eruptions.

  15. Do German drivers use their smartphones safely?-Not really!

    Science.gov (United States)

    Vollrath, Mark; Huemer, Anja Katharina; Teller, Carolin; Likhacheva, Anastasia; Fricke, Jana

    2016-11-01

    Research in the laboratory as well as in naturalistic driving studies has shown that texting while driving seems to be the most dangerous driver distraction. However, there is still some discussion about the extent to which drivers adapt their behavior to the traffic situation. Accordingly, they might use their phones only in easy driving situations but refrain from doing so when driving becomes more demanding. For Germany, no reliable data on these topics could be found although overall smartphone use has also increased exponentially in this country. As observational studies have proven to be an effective means to gather these data, such a study was done observing 11,837 drivers in three big German cities (Braunschweig, Hannover, Berlin) during daytime. An alarmingly high rate of texting while driving was found (4.5%) as compared to other international studies. This was even more frequent than the use of handheld (2.2%) and hands-free (1.7%) phones combined. Thus, there seems to be a special problem in Germany with texting which should be further examined as this activity is highly distracting. Finally, there was some indication that drivers adapt their secondary task activities to the requirements of the driving task (e.g. somewhat less texting when moving than when stationary at a red traffic light). However, these adaptations were not very strong. Thus, drivers seem to underestimate the dangers due to distraction. This could be a starting point for countermeasures which increase this awareness of danger.

  16. Driver Adaptive Warning Systems

    Science.gov (United States)

    1998-03-01

    corrective measures are being taken, such as: • A high steering wheel rate, indicating a correction. • A turn signal being active. • Brake being...fields include lane position, road curvature, steering angle, turn signal state, velocity, and system uncertainty. See Figure 3 for examples of these... turn signal when changing lanes. I am present in the van during the test run, sitting in the passenger seat. The touch screen that displays the RALPH

  17. Driver-centred vehicle automation: using network analysis for agent-based modelling of the driver in highly automated driving systems.

    Science.gov (United States)

    Banks, Victoria A; Stanton, Neville A

    2016-11-01

    To the average driver, the concept of automation in driving infers that they can become completely 'hands and feet free'. This is a common misconception, however, one that has been shown through the application of Network Analysis to new Cruise Assist technologies that may feature on our roads by 2020. Through the adoption of a Systems Theoretic approach, this paper introduces the concept of driver-initiated automation which reflects the role of the driver in highly automated driving systems. Using a combination of traditional task analysis and the application of quantitative network metrics, this agent-based modelling paper shows how the role of the driver remains an integral part of the driving system implicating the need for designers to ensure they are provided with the tools necessary to remain actively in-the-loop despite giving increasing opportunities to delegate their control to the automated subsystems. Practitioner Summary: This paper describes and analyses a driver-initiated command and control system of automation using representations afforded by task and social networks to understand how drivers remain actively involved in the task. A network analysis of different driver commands suggests that such a strategy does maintain the driver in the control loop.

  18. Desensitization mechanism in prokaryotic ligand-gated ion channel.

    Science.gov (United States)

    Velisetty, Phanindra; Chakrapani, Sudha

    2012-05-25

    Crystal structures of Gloeobacter violaceus ligand-gated ion channel (GLIC), a proton-gated prokaryotic homologue of pentameric ligand-gated ion channel (LGIC) from G. violaceus, have provided high-resolution models of the channel architecture and its role in selective ion conduction and drug binding. However, it is still unclear which functional states of the LGIC gating scheme these crystal structures represent. Much of this uncertainty arises from a lack of thorough understanding of the functional properties of these prokaryotic channels. To elucidate the molecular events that constitute gating, we have carried out an extensive characterization of GLIC function and dynamics in reconstituted proteoliposomes by patch clamp measurements and EPR spectroscopy. We find that GLIC channels show rapid activation upon jumps to acidic pH followed by a time-dependent loss of conductance because of desensitization. GLIC desensitization is strongly coupled to activation and is modulated by voltage, permeant ions, pore-blocking drugs, and membrane cholesterol. Many of these properties are parallel to functions observed in members of eukaryotic LGIC. Conformational changes in loop C, measured by site-directed spin labeling and EPR spectroscopy, reveal immobilization during desensitization analogous to changes in LGIC and acetylcholine binding protein. Together, our studies suggest conservation of mechanistic aspects of desensitization among LGICs of prokaryotic and eukaryotic origin.

  19. Pressure locking and thermal binding of gate valves

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, E.M.

    1996-12-01

    Pressure locking and thermal binding represent potential common mode failure mechanisms that can cause safety-related power-operated gate valves to fail in the closed position, thus rendering redundant safety-related systems incapable of performing their safety functions. Supplement 6 to Generic Letter 89-10, {open_quotes}Safety-Related Motor-Operated Gate Valve Testing and Surveillance,{close_quotes} provided an acceptable approach to addressing pressure locking and thermal binding of gate valves. More recently, the NRC has issued Generic Letter 95-07, {open_quotes}Pressure Locking and Thermal Binding of Safety-Related Power-Operated Gate Valves,{close_quotes} to request that licensees take certain actions to ensure that safety-related power-operated gate valves that are susceptible to pressure locking or thermal binding are capable of performing their safety functions within the current licensing bases. Over the past two years, several plants in Region I determined that valves in certain systems were potentially susceptible to pressure locking and thermal binding, and have taken various corrective actions. The NRC Region I Systems Engineering Branch has been actively involved in the inspection of licensee actions in response to the pressure locking and thermal binding issue. Region I continues to maintain an active involvement in this area, including participation with the Office of Nuclear Reactor Regulation in reviewing licensee responses to Generic Letter 95-07.

  20. Respiratory gating in cardiac PET

    DEFF Research Database (Denmark)

    Lassen, Martin Lyngby; Rasmussen, Thomas; Christensen, Thomas E

    2017-01-01

    BACKGROUND: Respiratory motion due to breathing during cardiac positron emission tomography (PET) results in spatial blurring and erroneous tracer quantification. Respiratory gating might represent a solution by dividing the PET coincidence dataset into smaller respiratory phase subsets. The aim...... stress (82)RB-PET. Respiratory rates and depths were measured by a respiratory gating system in addition to registering actual respiratory rates. Patients undergoing adenosine stress showed a decrease in measured respiratory rate from initial to later scan phase measurements [12.4 (±5.7) vs 5.6 (±4.......7) min(-1), P PET...

  1. Pregnenolone sulfate activates basic region leucine zipper transcription factors in insulinoma cells: role of voltage-gated Ca2+ channels and transient receptor potential melastatin 3 channels.

    Science.gov (United States)

    Müller, Isabelle; Rössler, Oliver G; Thiel, Gerald

    2011-12-01

    The neurosteroid pregnenolone sulfate activates a signaling cascade in insulinoma cells involving activation of extracellular signal-regulated protein kinase and enhanced expression of the transcription factor Egr-1. Here, we show that pregnenolone sulfate stimulation leads to a significant elevation of activator protein-1 (AP-1) activity in insulinoma cells. Expression of the basic region leucine zipper (bZIP) transcription factors c-Jun and c-Fos is up-regulated in insulinoma cells and pancreatic β-cells in primary culture after pregnenolone sulfate stimulation. Up-regulation of a chromatin-embedded c-Jun promoter/luciferase reporter gene transcription in pregnenolone sulfate-stimulated insulinoma cells was impaired when the AP-1 binding sites were mutated, indicating that these motifs function as pregnenolone sulfate response elements. In addition, phosphorylation of cAMP response element (CRE)-binding protein is induced and transcription of a CRE-controlled reporter gene is stimulated after pregnenolone sulfate treatment, indicating that the CRE functions as a pregnenolone sulfate response element as well. Pharmacological and genetic experiments revealed that both L-type Ca(2+) channels and transient receptor potential melastatin 3 (TRPM3) channels are essential for connecting pregnenolone sulfate stimulation with enhanced AP-1 activity and bZIP-mediated transcription in insulinoma cells. In contrast, pregnenolone sulfate stimulation did not enhance AP-1 activity or c-Jun and c-Fos expression in pituitary corticotrophs that express functional L-type Ca(2+) channels but only trace amounts of TRPM3. We conclude that expression of L-type Ca(2+) channels is not sufficient to activate bZIP-mediated gene transcription by pregnenolone sulfate. Rather, additional expression of TRPM3 or depolarization of the cells is required to connect pregnenolone sulfate stimulation with enhanced gene transcription.

  2. Chemical synthesis of tetracyclic terpenes and evaluation of antagonistic activity on endothelin-A receptors and voltage-gated calcium channels.

    Science.gov (United States)

    Lu, Jianyu; Aguilar, Angelo; Zou, Bende; Bao, Weier; Koldas, Serkan; Shi, Aibin; Desper, John; Wangemann, Philine; Xie, Xinmin Simon; Hua, Duy H

    2015-09-01

    A class of tetracyclic terpenes was synthesized and evaluated for antagonistic activity of endothelin-1 (ET-1) induced vasoconstriction and inhibitory activity of voltage-activated Ca(2+) channels. Three repeated Robinson annulation reactions were utilized to construct the tetracyclic molecules. A stereoselective reductive Robinson annulation was discovered for the formation of optically pure tricyclic terpenes. Stereoselective addition of cyanide to the hindered α-face of tetracyclic enone (-)-18 was found and subsequent transformation into the aldehyde function was affected by the formation of bicyclic hemiiminal (-)-4. Six selected synthetic tetracyclic terpenes show inhibitory activities in ET-1 induced vasoconstriction in the gerbil spiral modiolar artery with putative affinity constants ranging between 93 and 319 nM. Moreover, one compound, (-)-3, was evaluated further and found to inhibit voltage-activated Ca(2+) currents but not to affect Na(+) or K(+) currents in dorsal root ganglion cells under similar concentrations. These observations imply a dual mechanism of action. In conclusion, tetracyclic terpenes represent a new class of hit molecules for the discovery of new drugs for the treatment of pulmonary hypertension and vascular related diseases.

  3. A holistic perspective on corporate sustainability drivers

    NARCIS (Netherlands)

    Lozano, R.

    2013-01-01

    Since company boards are increasingly discussing 'sustainability', it becomes necessary to examine the nature of sustainability drivers. Most approaches to corporate sustainability drivers have focused either on internal or external drivers. This paper is aimed at providing a more holistic perspecti

  4. A holistic perspective on corporate sustainability drivers

    NARCIS (Netherlands)

    Lozano, Rodrigo

    2015-01-01

    Since company boards are increasingly discussing 'sustainability', it becomes necessary to examine the nature of sustainability drivers. Most approaches to corporate sustainability drivers have focused either on internal or external drivers. This paper is aimed at providing a more holistic perspecti

  5. Reversible logic gate using adiabatic superconducting devices

    National Research Council Canada - National Science Library

    Takeuchi, N; Yamanashi, Y; Yoshikawa, N

    2014-01-01

    .... However, until now, no practical reversible logic gates have been demonstrated. One of the problems is that reversible logic gates must be built by using extremely energy-efficient logic devices...

  6. BEARING FORCES OF EMERGENCY GATE DURING SHUTOFF

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    For an emergency gate in a surge tank, forces acting on the gate were systematically tested and analyzed, including pulling forces resulted from water hammer because of the sudden rejection of all loads in turbine units under different gate levels, and forces during the process of gate shutoff under the conditions of different number of running turbine units. Besides, for the pulling force on the top of gate, their variation processes with time and extent of gate opening were also tested. It is shown that the calculated value of gate pulling force agrees on the whole with the tested one. The results indicate that the emergency gate in the extraordinary large surge tank of WWS hydropower station is safe under the above testing conditions. The related data in the present paper are helpful for the study on an emergency in a sure tank.

  7. Gating Technology for Vertically Parted Green Sand Moulds

    DEFF Research Database (Denmark)

    Larsen, Per

    Gating technology for vertically parted green sand moulds. Literature study of different ways of designing gating systems.......Gating technology for vertically parted green sand moulds. Literature study of different ways of designing gating systems....

  8. The expression of hyperpolarization activated cyclic nucleotide gated (HCN channels in the rat ovary are dependent on the type of cell and the reproductive age of the animal: a laboratory investigation

    Directory of Open Access Journals (Sweden)

    Page Carly

    2008-08-01

    Full Text Available Abstract Background Aim of this study was to test the hypothesis that levels of hyperpolarization activated cyclic nucleotide gated channels 1 to 4 (HCN1-4 are linked to the reproductive age of the ovary. Methods Young, adult, and reproductively aged ovaries were collected from Sprague-Dawley rats. RT-PCR and western blot analysis of ovaries was performed to investigate the presence of mRNA and total protein for HCN1-4. Immunohistochemistry with semiquantitative H score analysis was performed using whole ovarian histologic sections. Results RT-PCR analysis showed the presence of mRNA for HCN1-4. Western blot analysis revealed HCN1-3 proteins in all ages of ovarian tissues. Immunohistochemistry with H score analysis demonstrated distinct age-related changes in patterns of HCN1-3 in the oocytes, granulosa cells, theca cells, and corpora lutea. HCN4 was present only in the oocytes, with declining levels during the reproduction lifespan. Conclusion The evidence presented here demonstrates cell-type and developmental age patterns of HCN1-4 channel expression in rat ovaries. Based on this, we hypothesize that HCN channels have functional significance in rat ovaries and may have changing roles in reproductive aging.

  9. A G326E substitution in the glutamate-gated chloride channel 3 (GluCl3) of the two-spotted spider mite Tetranychus urticae abolishes the agonistic activity of macrocyclic lactones.

    Science.gov (United States)

    Mermans, Catherine; Dermauw, Wannes; Geibel, Sven; Van Leeuwen, Thomas

    2017-07-24

    The macrocyclic lactones abamectin and milbemectin are frequently used to control phytophagous mites such as Tetranychus urticae. Consequently, resistance has developed and was genetically linked with substitutions in the glutamate-gated chloride channel (GluCl) subunits TuGluCl1 and TuGluCl3. Here, we functionally validated a G326E substitution in TuGluCl3 by functional expression in Xenopus laevis oocytes followed by two-electrode voltage-clamp electrophysiology. Homomeric wild-type and mutated GluCl3 were successfully expressed. l-glutamic-acid-induced currents exhibited a rapid onset equal in both channels and EC50 for l-glutamic-acid was in the micromolar range (384.2 μm and 292.7 μm, respectively). Abamectin and milbemycin A4 elicited sustained currents in wild-type GluCl3, but the G326E substitution completely abolished the agonistic activity of macrocyclic lactones. A target-site mutation in Tu GluCl3 contributes to avermectin resistance in T. urticae. However, given the multitude of channel genes and the potential additive or synergistic effects of mutations, to what extent mutations determine the often extremely strong resistance phenotype in the field deserves further study. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  10. Global drivers, sustainable manufacturing and systems ergonomics.

    Science.gov (United States)

    Siemieniuch, C E; Sinclair, M A; Henshaw, M J deC

    2015-11-01

    This paper briefly explores the expected impact of the 'Global Drivers' (such as population demographics, food security; energy security; community security and safety), and the role of sustainability engineering in mitigating the potential effects of these Global Drivers. The message of the paper is that sustainability requires a significant input from Ergonomics/Human Factors, but the profession needs some expansion in its thinking in order to make this contribution. Creating a future sustainable world in which people experience an acceptable way of life will not happen without a large input from manufacturing industry into all the Global Drivers, both in delivering products that meet sustainability criteria (such as durability, reliability, minimised material requirement and low energy consumption), and in developing sustainable processes to deliver products for sustainability (such as minimum waste, minimum emissions and low energy consumption). Appropriate changes are already being implemented in manufacturing industry, including new business models, new jobs and new skills. Considerable high-level planning around the world is in progress and is bringing about these changes; for example, there is the US 'Advanced Manufacturing National Program' (AMNP)', the German 'Industrie 4.0' plan, the French plan 'la nouvelle France industrielle' and the UK Foresight publications on the 'Future of Manufacturing'. All of these activities recognise the central part that humans will continue to play in the new manufacturing paradigms; however, they do not discuss many of the issues that systems ergonomics professionals acknowledge. This paper discusses a number of these issues, highlighting the need for some new thinking and knowledge capture by systems ergonomics professionals. Among these are ethical issues, job content and skills issues. Towards the end, there is a summary of knowledge extensions considered necessary in order that systems ergonomists can be fully

  11. Drivers for animal welfare policies in Europe.

    Science.gov (United States)

    Dalla Villa, P; Matthews, L R; Alessandrini, B; Messori, S; Migliorati, G

    2014-04-01

    The European region has been, and remains, a global leader in the development of animal welfare policies. The region has a great diversity of cultures and religions, different levels of socio-economic development, and varied legislation, policies and practices. Nevertheless, there are common drivers for animal welfare policy based on a history of animal welfare ethics and obligations to animal users and society in general. A unifying goal of countries in the region is to achieve sustainable compliance with the World Organisation for Animal Health (OIE) standards on animal health and welfare. Ethics isthe overarching driver, supported by the actions of governmental, inter-governmental and non-governmental activities, markets and trade, science and knowledge. Historically, organisations involved in promoting animal welfare have tended to act in isolation. For example, non-governmental organisations (NGOs) have run campaigns to influence retailers and the welfare policies of their farmer suppliers. Increasingly, different organisations with common or complementary goals are working together. For example, competent authorities, inter-governmental bodies and NGOs have combined their efforts to address dog population control across several countries in the region. Also, animal welfare is becoming integrated into the corporate social responsibility targets of private companies. Science and knowledge, as drivers and tools, are assisting with the harmonisation of welfare standards, e.g. by providing a common basis for measuring welfare impacts through animal-based measures and widespread sharing of this information. Current trends suggest that there will be greater collaboration among the organisations driving change, and increasing convergence of animal welfare strategies and welfare assessment tools. The result will be increased harmonisation of animal welfare standards throughout the region.

  12. FIVE PHASE PENTAGON HYBRID STEPPER MOTOR INTELLIGENT HALF/FULL DRIVER

    Directory of Open Access Journals (Sweden)

    Alexandru Morar

    2017-06-01

    Full Text Available Stepper motors are very well suited for positioning applications since they can achieve very good positional accuracy without complicated feedback loops associated with servo systems. In this paper, an intelligent five-phase stepper motor driver of business card size proposed. Constant current chopping technique was applied for the purposes of high torque, high velocity and high efficiency. The driver was designed to drive a middle-sized hybrid stepper motor with wire current rating from 0.4 to 1.5A. An up-to-dated translator of five-phase stepping motor was used to drive the gates of N- channel MOSFET array. The resolution in full/half mode is 0.72/0.36 degrees/step. Moreover, an automatic power down circuit was used to limit the power consuming as the motor stops. Additionally, a self-testing program embedded in a 80C31-CPU (PCL838 can self-test whether the driver is normal or not. This embedded program including linear acceleration and deceleration routines also can serve as a positioning controller. The dimension of this driver is approximate 70x65x35 millimeters, which is smaller than a business card. Experimental results demonstrate that the responses of the driver can reach 60 kilo pulses per second

  13. Gate-enclosed NMOS transistors

    Institute of Scientific and Technical Information of China (English)

    Fan Xue; Li Ping; Li Wei; Zhang Bin; Xie Xiaodong; Wang Gang; Hu Bin; Zhai Yahong

    2011-01-01

    In order to quantitatively compare the design cost and performance of various gate styles,NMOS transistors with two-edged,annular and ring gate layouts were designed and fabricated by a commercial 0.35 μm CMOS process.By comparing the minimum W/L ratios and transistor areas,it was found that either the annular layout or its ring counterpart incurs a higher area penalty that depends on the W/L ratio of the transistor to be designed.Furthermore,by comparing the output and transfer characteristics of the transistors and analyzing the popular existing methods for extracting the effective W/L ratio,it was shown that the mid-line approximation for annular NMOS could incur an error of more than 10%.It was also demonstrated that the foundry-provided extraction tool needs significant adaptation when being applied to the enclosed-gate transistors,since it is targeted only toward the two-edged transistor.A simple approach for rough extraction of the W/L ratio for the ring-gate NMOS was presented and its effectiveness was confirmed by the experimental results with an error up to 8%.

  14. Bill Gates eyes healthcare market.

    Science.gov (United States)

    Dunbar, C

    1995-02-01

    The entrepreneurial spirit is still top in Bill Gates' mind as he look toward healthcare and other growth industries. Microsoft's CEO has not intention of going the way of other large technology companies that became obsolete before they could compete today.

  15. Transcription Factors Synergistically Activated at the Crossing of the Restriction Point between G1 and S Cell Cycle Phases. Pathologic Gate Opening during Multi-Hit Malignant Transformation

    Directory of Open Access Journals (Sweden)

    Nicoletta Castagnino

    2016-12-01

    Full Text Available Transcription factors (TFs represent key regulators of gene-expression patterns controlling cell behavior. TFs are active at nuclear – chromatin levels. TFs do not act in isolation; small sets of TFs cooperate toward the transcription of sets of mRNAs and consequently the translation of new proteins (the molecular phenotypes of a cell. Most TFs are activated through a cascade of biochemical reactions mediated by receptors expressed on the target cell surface. Nuclear Receptors (NRs are transcription factors activated instead by small hydrophobic molecules capable of crossing the plasma membrane. The convergence of different pathways on TFs and their posttranslational modifications ensure that the external stimuli generate appropriate and integrated responses. The reconstruction of the molecular anatomy of these pathways through Molecular Interactions Maps (MIMs can depict these intricate interactions. A mathematical modeling approach simulates/mimics their mechanism of action in normal and pathological conditions. We can simulate the effect of virtual hits in neoplastic transformation as mutations/alterations in these pathways. We can also simulate the effect of targeted inhibitors on these deregulated pathways. This strategy can help to guide an appropriate combination of targeted drugs in the treatment of a cancer patient, a major innovative perspective of incoming years.

  16. A new role for AMP-activated protein kinase in the circadian regulation of L-type voltage-gated calcium channels in late-stage embryonic retinal photoreceptors.

    Science.gov (United States)

    Huang, Cathy C Y; Shi, Liheng; Lin, Chia-Hung; Kim, Andy Jeesu; Ko, Michael L; Ko, Gladys Y-P

    2015-11-01

    AMP-activated protein kinase (AMPK) is a cellular energy sensor, which is activated when the intracellular ATP production decreases. The activities of AMPK display circadian rhythms in various organs and tissues, indicating that AMPK is involved in the circadian regulation of cellular metabolism. In vertebrate retina, the circadian clocks regulate many aspects of retinal function and physiology, including light/dark adaption, but whether and how AMPK was involved in the retinal circadian rhythm was not known. We hypothesized that the activation of AMPK (measured as phosphorylated AMPK) in the retina was under circadian control, and AMPK might interact with other intracellular signaling molecules to regulate photoreceptor physiology. We combined ATP assays, western blots, immunostaining, patch-clamp recordings, and pharmacological treatments to decipher the role of AMPK in the circadian regulation of photoreceptor physiology. We found that the overall retinal ATP content displayed a diurnal rhythm that peaked at early night, which was nearly anti-phase to the diurnal and circadian rhythms of AMPK phosphorylation. AMPK was also involved in the circadian phase-dependent regulation of photoreceptor L-type voltage-gated calcium channels (L-VGCCs), the ion channel essential for sustained neurotransmitter release. The activation of AMPK dampened the L-VGCC currents at night with a corresponding decrease in protein expression of the L-VGCCα1 pore-forming subunit, while inhibition of AMPK increased the L-VGCC current during the day. AMPK appeared to be upstream of extracellular-signal-regulated kinase and mammalian/mechanistic target of rapamycin complex 1 (mTORC1) but downstream of adenylyl cyclase in regulating the circadian rhythm of L-VGCCs. Hence, as a cellular energy sensor, AMPK integrates into the cell signaling network to regulate the circadian rhythm of photoreceptor physiology. We found that in chicken embryonic retina, the activation of AMP-activated protein

  17. Quantum Circuit Synthesis using a New Quantum Logic Gate Library of NCV Quantum Gates

    Science.gov (United States)

    Li, Zhiqiang; Chen, Sai; Song, Xiaoyu; Perkowski, Marek; Chen, Hanwu; Zhu, Wei

    2017-04-01

    Since Controlled-Square-Root-of-NOT (CV, CV‡) gates are not permutative quantum gates, many existing methods cannot effectively synthesize optimal 3-qubit circuits directly using the NOT, CNOT, Controlled-Square-Root-of-NOT quantum gate library (NCV), and the key of effective methods is the mapping of NCV gates to four-valued quantum gates. Firstly, we use NCV gates to create the new quantum logic gate library, which can be directly used to get the solutions with smaller quantum costs efficiently. Further, we present a novel generic method which quickly and directly constructs this new optimal quantum logic gate library using CNOT and Controlled-Square-Root-of-NOT gates. Finally, we present several encouraging experiments using these new permutative gates, and give a careful analysis of the method, which introduces a new idea to quantum circuit synthesis.

  18. Quantum Circuit Synthesis using a New Quantum Logic Gate Library of NCV Quantum Gates

    Science.gov (United States)

    Li, Zhiqiang; Chen, Sai; Song, Xiaoyu; Perkowski, Marek; Chen, Hanwu; Zhu, Wei

    2016-12-01

    Since Controlled-Square-Root-of-NOT (CV, CV‡) gates are not permutative quantum gates, many existing methods cannot effectively synthesize optimal 3-qubit circuits directly using the NOT, CNOT, Controlled-Square-Root-of-NOT quantum gate library (NCV), and the key of effective methods is the mapping of NCV gates to four-valued quantum gates. Firstly, we use NCV gates to create the new quantum logic gate library, which can be directly used to get the solutions with smaller quantum costs efficiently. Further, we present a novel generic method which quickly and directly constructs this new optimal quantum logic gate library using CNOT and Controlled-Square-Root-of-NOT gates. Finally, we present several encouraging experiments using these new permutative gates, and give a careful analysis of the method, which introduces a new idea to quantum circuit synthesis.

  19. Polar Warming Drivers

    Science.gov (United States)

    McDunn, T. L.; Bougher, S. W.; Mischna, M. A.; Murphy, J. R.

    2012-12-01

    Polar warming is a dynamically induced temperature enhancement over mid-to-high latitudes that results in a reversed (poleward) meridional temperature gradient. This phenomenon was recently characterized over the 40-90 km altitude region [1] based on nearly three martian years of Mars Climate Sounder observations [2, 3]. Here we investigate which forcing mechanisms affect the magnitude and distribution of the observed polar warming by conducting simulations with the Mars Weather Research and Forecasting General Circulation Model [4, 5]. We present simulations confirming the influence topography [6] and dust loading [e.g., 7] have upon polar warming. We then present simulations illustrating the modulating influence gravity wave momentum deposition exerts upon polar warming, consistent with previous modeling studies [e.g., 8]. The results of this investigation suggest the magnitude and distribution of polar warming in the martian middle atmosphere is modified by gravity wave activity and that the characteristics of the gravity waves that most significantly affect polar warming vary with season. References: [1] McDunn, et al., 2012 (JGR), [2]Kleinböhl, et al., 2009 (JGR), [3] Kleinböhl, et al., 2011 (JQSRT), [4] Richardson, et al., 2007 (JGR), [5] Mischna, et al., 2011 (Planet. Space Sci.), [6] Richardson and Wilson, 2002 (Nature), [7] Haberle, et al., 1982 (Icarus), [8] Barnes, 1990 (JGR).

  20. Factors Contributing to Crashes among Young Drivers

    Directory of Open Access Journals (Sweden)

    Lyndel J. Bates

    2014-08-01

    Full Text Available Young drivers are the group of drivers most likely to crash. There are a number of factors that contribute to the high crash risk experienced by these drivers. While some of these factors are intrinsic to the young driver, such as their age, gender or driving skill, others relate to social factors and when and how often they drive. This article reviews the factors that affect the risk of young drivers crashing to enable a fuller understanding of why this risk is so high in order to assist in developing effective countermeasures.

  1. Factors Contributing to Crashes among Young Drivers.

    Science.gov (United States)

    Bates, Lyndel J; Davey, Jeremy; Watson, Barry; King, Mark J; Armstrong, Kerry

    2014-08-01

    Young drivers are the group of drivers most likely to crash. There are a number of factors that contribute to the high crash risk experienced by these drivers. While some of these factors are intrinsic to the young driver, such as their age, gender or driving skill, others relate to social factors and when and how often they drive. This article reviews the factors that affect the risk of young drivers crashing to enable a fuller understanding of why this risk is so high in order to assist in developing effective countermeasures.

  2. GPS Usage in a Population of Low-Vision Drivers.

    Science.gov (United States)

    Cucuras, Maria; Chun, Robert; Lee, Patrick; Jay, Walter M; Pusateri, Gregg

    2017-01-01

    We surveyed bioptic and non-bioptic low-vision drivers in Illinois, USA, to determine their usage of global positioning system (GPS) devices. Low-vision patients completed an IRB-approved phone survey regarding driving demographics and usage of GPS while driving. Participants were required to be active drivers with an Illinois driver's license, and met one of the following criteria: best-corrected visual acuity (BCVA) less than or equal to 20/40, central or significant peripheral visual field defects, or a combination of both. Of 27 low-vision drivers, 10 (37%) used GPS while driving. The average age for GPS users was 54.3 and for non-users was 77.6. All 10 drivers who used GPS while driving reported increased comfort or safety level. Since non-GPS users were significantly older than GPS users, it is likely that older participants would benefit from GPS technology training from their low-vision eye care professionals.

  3. Visualization drivers for Geant4

    Energy Technology Data Exchange (ETDEWEB)

    Beretvas, Andy; /Fermilab

    2005-10-01

    This document is on Geant4 visualization tools (drivers), evaluating pros and cons of each option, including recommendations on which tools to support at Fermilab for different applications. Four visualization drivers are evaluated. They are OpenGL, HepRep, DAWN and VRML. They all have good features, OpenGL provides graphic output without an intermediate file. HepRep provides menus to assist the user. DAWN provides high quality plots and even for large files produces output quickly. VRML uses the smallest disk space for intermediate files. Large experiments at Fermilab will want to write their own display. They should proceed to make this display graphics independent. Medium experiment will probably want to use HepRep because of it's menu support. Smaller scale experiments will want to use OpenGL in the spirit of having immediate response, good quality output and keeping things simple.

  4. Transition of Control: automation giving back control to the driver

    NARCIS (Netherlands)

    Willemsen, D.M.C.; Stuiver, A.; Hogema, J.

    2014-01-01

    The automotive domain is currently moving towards automated driver assistance applications, like automatic evasive maneuvers to avoid accidents, and even beyond assistance towards automated driving. However, in the near future these systems will only be active under certain conditions, thus still re

  5. Transition of Control : Automation Giving Back Control to the Driver

    NARCIS (Netherlands)

    Ahram, T; Karwowski, W; Marek, T; Willemsen, D; Stuiver, A; Hogema, J

    2014-01-01

    The automotive domain is currently moving towards automated driver assistance applications, like automatic evasive maneuvers to avoid accidents, and even beyond assistance towards automated driving. However, in the near future these systems will only be active under certain conditions, thus still re

  6. The relationship between driver distraction and mental workload

    NARCIS (Netherlands)

    Schaap, T.W.; Horst, A.R.A. van der; Arem, B. van; Brookhuis, K.A.

    2009-01-01

    Driver distraction is caused by a competing activity and leads to unsafe driving. Mental workload changes with task demands and influences performance. Though distraction and mental workload are strongly related, they are not the same. Performance motivation and task engagement influence performance

  7. Drivers of stability of climate coalitions in the STACO model

    NARCIS (Netherlands)

    Dellink, R.B.

    2011-01-01

    This paper investigates which drivers affect the formation and stability of international climate agreements (ICAs). The applied model STACO is used to project costs and benefits of an international agreement on climate change mitigation activities. The simulation results show that an incentive-base

  8. Food consumption trends and drivers

    OpenAIRE

    Kearney, John

    2010-01-01

    A picture of food consumption (availability) trends and projections to 2050, both globally and for different regions of the world, along with the drivers largely responsible for these observed consumption trends are the subject of this review. Throughout the world, major shifts in dietary patterns are occurring, even in the consumption of basic staples towards more diversified diets. Accompanying these changes in food consumption at a global and regional level have been considerable health co...

  9. Global desertification: Drivers and feedbacks

    Science.gov (United States)

    D'Odorico, Paolo; Bhattachan, Abinash; Davis, Kyle F.; Ravi, Sujith; Runyan, Christiane W.

    2013-01-01

    Desertification is a change in soil properties, vegetation or climate, which results in a persistent loss of ecosystem services that are fundamental to sustaining life. Desertification affects large dryland areas around the world and is a major cause of stress in human societies. Here we review recent research on the drivers, feedbacks, and impacts of desertification. A multidisciplinary approach to understanding the drivers and feedbacks of global desertification is motivated by our increasing need to improve global food production and to sustainably manage ecosystems in the context of climate change. Classic desertification theories look at this process as a transition between stable states in bistable ecosystem dynamics. Climate change (i.e., aridification) and land use dynamics are the major drivers of an ecosystem shift to a “desertified” (or “degraded”) state. This shift is typically sustained by positive feedbacks, which stabilize the system in the new state. Desertification feedbacks may involve land degradation processes (e.g., nutrient loss or salinization), changes in rainfall regime resulting from land-atmosphere interactions (e.g., precipitation recycling, dust emissions), or changes in plant community composition (e.g., shrub encroachment, decrease in vegetation cover). We analyze each of these feedback mechanisms and discuss their possible enhancement by interactions with socio-economic drivers. Large scale effects of desertification include the emigration of “environmental refugees” displaced from degraded areas, climatic changes, and the alteration of global biogeochemical cycles resulting from the emission and long-range transport of fine mineral dust. Recent research has identified some possible early warning signs of desertification, which can be used as indicators of resilience loss and imminent shift to desert-like conditions. We conclude with a brief discussion on some desertification control strategies implemented in different

  10. A control theoretic model of driver steering behavior

    Science.gov (United States)

    Donges, E.

    1977-01-01

    A quantitative description of driver steering behavior such as a mathematical model is presented. The steering task is divided into two levels: (1) the guidance level involving the perception of the instantaneous and future course of the forcing function provided by the forward view of the road, and the response to it in an anticipatory open-loop control mode; (2) the stabilization level whereby any occuring deviations from the forcing function are compensated for in a closed-loop control mode. This concept of the duality of the driver's steering activity led to a newly developed two-level model of driver steering behavior. Its parameters are identified on the basis of data measured in driving simulator experiments. The parameter estimates of both levels of the model show significant dependence on the experimental situation which can be characterized by variables such as vehicle speed and desired path curvature.

  11. Organic nano-floating-gate transistor memory with metal nanoparticles

    Science.gov (United States)

    Van Tho, Luu; Baeg, Kang-Jun; Noh, Yong-Young

    2016-04-01

    Organic non-volatile memory is advanced topics for various soft electronics applications as lightweight, low-cost, flexible, and printable solid-state data storage media. As a key building block, organic field-effect transistors (OFETs) with a nano-floating gate are widely used and promising structures to store digital information stably in a memory cell. Different types of nano-floating-gates and their various synthesis methods have been developed and applied to fabricate nanoparticle-based non-volatile memory devices. In this review, recent advances in the classes of nano-floating-gate OFET memory devices using metal nanoparticles as charge-trapping sites are briefly reviewed. Details of device fabrication, characterization, and operation mechanisms are reported based on recent research activities reported in the literature.

  12. The drivers of tropical speciation.

    Science.gov (United States)

    Smith, Brian Tilston; McCormack, John E; Cuervo, Andrés M; Hickerson, Michael J; Aleixo, Alexandre; Cadena, Carlos Daniel; Pérez-Emán, Jorge; Burney, Curtis W; Xie, Xiaoou; Harvey, Michael G; Faircloth, Brant C; Glenn, Travis C; Derryberry, Elizabeth P; Prejean, Jesse; Fields, Samantha; Brumfield, Robb T

    2014-11-20

    Since the recognition that allopatric speciation can be induced by large-scale reconfigurations of the landscape that isolate formerly continuous populations, such as the separation of continents by plate tectonics, the uplift of mountains or the formation of large rivers, landscape change has been viewed as a primary driver of biological diversification. This process is referred to in biogeography as vicariance. In the most species-rich region of the world, the Neotropics, the sundering of populations associated with the Andean uplift is ascribed this principal role in speciation. An alternative model posits that rather than being directly linked to landscape change, allopatric speciation is initiated to a greater extent by dispersal events, with the principal drivers of speciation being organism-specific abilities to persist and disperse in the landscape. Landscape change is not a necessity for speciation in this model. Here we show that spatial and temporal patterns of genetic differentiation in Neotropical birds are highly discordant across lineages and are not reconcilable with a model linking speciation solely to landscape change. Instead, the strongest predictors of speciation are the amount of time a lineage has persisted in the landscape and the ability of birds to move through the landscape matrix. These results, augmented by the observation that most species-level diversity originated after episodes of major Andean uplift in the Neogene period, suggest that dispersal and differentiation on a matrix previously shaped by large-scale landscape events was a major driver of avian speciation in lowland Neotropical rainforests.

  13. Gating function of isoleucine-116 in TM-3 (position III:16/3.40) for the activity state of the CC-chemokine receptor 5 (CCR5)

    DEFF Research Database (Denmark)

    Steen, A; Sparre-Ulrich, A H; Thiele, Stefanie;

    2014-01-01

    ;G286F]-CCR5 (V:13/5.47;VII:09/7.42) were determined in G-protein- and β-arrestin-coupled signalling. Computational modelling monitored changes in amino acid conformation. KEY RESULTS: [L203F]-CCR5 increased the basal level of G-protein coupling (20-70% of Emax ) and β-arrestin recruitment (50% of Emax......TM receptors - it is a leucine indicating an altered function. Here, we describe the significance of this position and its possible interaction with TM-3 for CCR5 activity. EXPERIMENTAL APPROACH: The effects of [L203F]-CCR5 in TM-5 (position V:13/5.47), [I116A]-CCR5 in TM-3 (III:16/3.40) and [L203F...... ) with a threefold increase in agonist potency. In silico, [I116A]-CCR5 switched χ1-angle in [L203F]-CCR5. Furthermore, [I116A]-CCR5 was constitutively active to a similar degree as [L203F]-CCR5. Tyr(244) in TM-6 (VI:09/6.44) moved towards TM-5 in silico, consistent with its previously shown function for CCR5...

  14. Effect of down-regulation of voltage-gated sodium channel Nav1.7 on activation of astrocytes and microglia in DRG in rats with cancer pain

    Institute of Scientific and Technical Information of China (English)

    Jun Pan; Xiang-Jin Lin; Zhi-Heng Ling; You-Zhi Cai

    2015-01-01

    Objective:To evaluate the effect of down-regulation of Nav1.7 on the activation of astrocytes and microglia in DRG of rats with cancer pain, and explore the transmission of the nociceptive information.Methods:Lentiviral vector harboring RNAi sequence targeting theNav1.7gene was constructed, and Walker 256 breast cancer cell and morphine was injected to build the bone cancer pain model and morphine tolerance model in rats. Lentiviral vector was injected. Rats in each model were divided into 4 groups: model group, PBS group, vehicle group and LV-Nav1.7 group. The expression levels of GFAP and OX42 in dorsal root ganglia (DRG) were measured.Results: After the animal model was built,the level of Nav1.7, GFAP and OX42 was improved obviously with the time prolonged, which was statistically significant (P<0.05). The expression level of GFAP and OX42 in the DRG in the LV-Nav1.7 group declined obviously compared to the model group, PBS group and vehicle group (P<0.05).Conclusions:Intrathecal injection of Navl.7 shRNA lentiviral vector can reduce the expression of Nav1.7 and inhibit the activation of astrocytes and microglia in DRG. The effort is also effective in morphine tolerance bone cancer pain model rats.

  15. Simultaneous optical recording in multiple cells by digital holographic microscopy of chloride current associated to activation of the ligand-gated chloride channel GABA(A) receptor.

    Science.gov (United States)

    Jourdain, Pascal; Boss, Daniel; Rappaz, Benjamin; Moratal, Corinne; Hernandez, Maria-Clemencia; Depeursinge, Christian; Magistretti, Pierre Julius; Marquet, Pierre

    2012-01-01

    Chloride channels represent a group of targets for major clinical indications. However, molecular screening for chloride channel modulators has proven to be difficult and time-consuming as approaches essentially rely on the use of fluorescent dyes or invasive patch-clamp techniques which do not lend themselves to the screening of large sets of compounds. To address this problem, we have developed a non-invasive optical method, based on digital holographic microcopy (DHM), allowing monitoring of ion channel activity without using any electrode or fluorescent dye. To illustrate this approach, GABA(A) mediated chloride currents have been monitored with DHM. Practically, we show that DHM can non-invasively provide the quantitative determination of transmembrane chloride fluxes mediated by the activation of chloride channels associated with GABA(A) receptors. Indeed through an original algorithm, chloride currents elicited by application of appropriate agonists of the GABA(A) receptor can be derived from the quantitative phase signal recorded with DHM. Finally, chloride currents can be determined and pharmacologically characterized non-invasively simultaneously on a large cellular sampling by DHM.

  16. Simultaneous optical recording in multiple cells by digital holographic microscopy of chloride current associated to activation of the ligand-gated chloride channel GABA(A receptor.

    Directory of Open Access Journals (Sweden)

    Pascal Jourdain

    Full Text Available Chloride channels represent a group of targets for major clinical indications. However, molecular screening for chloride channel modulators has proven to be difficult and time-consuming as approaches essentially rely on the use of fluorescent dyes or invasive patch-clamp techniques which do not lend themselves to the screening of large sets of compounds. To address this problem, we have developed a non-invasive optical method, based on digital holographic microcopy (DHM, allowing monitoring of ion channel activity without using any electrode or fluorescent dye. To illustrate this approach, GABA(A mediated chloride currents have been monitored with DHM. Practically, we show that DHM can non-invasively provide the quantitative determination of transmembrane chloride fluxes mediated by the activation of chloride channels associated with GABA(A receptors. Indeed through an original algorithm, chloride currents elicited by application of appropriate agonists of the GABA(A receptor can be derived from the quantitative phase signal recorded with DHM. Finally, chloride currents can be determined and pharmacologically characterized non-invasively simultaneously on a large cellular sampling by DHM.

  17. Replication NAND gate with light as input and output.

    Science.gov (United States)

    Samiappan, Manickasundaram; Dadon, Zehavit; Ashkenasy, Gonen

    2011-01-14

    Logic operations can highlight information transfer within complex molecular networks. We describe here the design of a peptide-based replication system that can be detected by following its fluorescence quenching. This process is used to negate the signal of light-activated replication, and thus to prepare the first replication NAND gate.

  18. Familial hemiplegic migraine CaV2.1 channel mutation R192Q enhances ATP-gated P2X3 receptor activity of mouse sensory ganglion neurons mediating trigeminal pain

    Directory of Open Access Journals (Sweden)

    Nair Asha

    2010-08-01

    Full Text Available Abstract Background The R192Q mutation of the CACNA1A gene, encoding for the α1 subunit of voltage-gated P/Q Ca2+ channels (Cav2.1, is associated with familial hemiplegic migraine-1. We investigated whether this gain-of-function mutation changed the structure and function of trigeminal neuron P2X3 receptors that are thought to be important contributors to migraine pain. Results Using in vitro trigeminal sensory neurons of a mouse genetic model knockin for the CACNA1A R192Q mutation, we performed patch clamp recording and intracellular Ca2+ imaging that showed how these knockin ganglion neurons generated P2X3 receptor-mediated responses significantly larger than wt neurons. These enhanced effects were reversed by the Cav2.1 blocker ω-agatoxin. We, thus, explored intracellular signalling dependent on kinases and phosphatases to understand the molecular regulation of P2X3 receptors of knockin neurons. In such cells we observed strong activation of CaMKII reversed by ω-agatoxin treatment. The CaMKII inhibitor KN-93 blocked CaMKII phosphorylation and the hyperesponsive P2X3 phenotype. Although no significant difference in membrane expression of knockin receptors was found, serine phosphorylation of knockin P2X3 receptors was constitutively decreased and restored by KN-93. No change in threonine or tyrosine phosphorylation was detected. Finally, pharmacological inhibitors of the phosphatase calcineurin normalized the enhanced P2X3 receptor responses of knockin neurons and increased their serine phosphorylation. Conclusions The present results suggest that the CACNA1A mutation conferred a novel molecular phenotype to P2X3 receptors of trigeminal ganglion neurons via CaMKII-dependent activation of calcineurin that selectively impaired the serine phosphorylation state of such receptors, thus potentiating their effects in transducing trigeminal nociception.

  19. Driving fatigue in professional drivers: a survey of truck and taxi drivers.

    Science.gov (United States)

    Meng, Fanxing; Li, Shuling; Cao, Lingzhi; Li, Musen; Peng, Qijia; Wang, Chunhui; Zhang, Wei

    2015-01-01

    Fatigue among truck drivers has been studied extensively; however, less is known regarding the fatigue experience of taxi drivers in heavily populated metropolitan areas. This study aimed to compare the differences and similarities between truck and taxi driver fatigue to provide implications for the fatigue management and education of professional drivers. A sample of 274 truck drivers and 286 taxi drivers in Beijing was surveyed via a questionnaire, which included items regarding work characteristics, fatigue experience, accident information, attitude toward fatigue, and methods of counteracting fatigue. Driver fatigue was prevalent among professional drivers, and it was even more serious for taxi drivers. Taxi drivers reported more frequent fatigue experiences and were involved in more accidents. Among the contributing factors to fatigue, prolonged driving time was the most important factor identified by both driver groups. Importantly, the reason for the engagement in prolonged driving was neither due to the lack of awareness concerning the serious outcome of fatigue driving nor because of their poor detection of fatigue. The most probable reason was the optimism bias, as a result of which these professional drivers thought that fatigue was more serious for other drivers than for themselves, and they thought that they were effective in counteracting the effect of fatigue on their driving performance. Moreover, truck drivers tended to employ methods that require stopping to counteract fatigue, whereas taxi drivers preferred methods that were simultaneous with driving. Although both driver groups considered taking a nap as one of the most effective means to address fatigue, this method was not commonly used. Interestingly, these drivers were aware that the methods they frequently used were not the most effective means to counteract fatigue. This study provides knowledge on truck and taxi drivers' characteristics in fatigue experience, fatigue attitude, and

  20. Environmental noise reduction for holonomic quantum gates

    CERN Document Server

    Parodi, Daniele; Solinas, Paolo; Zanghì, Nino

    2007-01-01

    We study the performance of holonomic quantum gates, driven by lasers, under the effect of a dissipative environment modeled as a thermal bath of oscillators. We show how to enhance the performance of the gates by suitable choice of the loop in the manifold of the controllable parameters of the laser. For a simplified, albeit realistic model, we find the surprising result that for a long time evolution the performance of the gate (properly estimated in terms of average fidelity) increases. On the basis of this result, we compare holonomic gates with the so-called STIRAP gates.

  1. Mixed-Species Logic Gates and High-Fidelity Universal Gate Set for Trapped-Ion Qubits

    Science.gov (United States)

    Tan, Ting Rei

    2016-05-01

    Precision control over hybrid physical systems at the quantum level is important for the realization of many quantum-based technologies. For trapped-ions, a hybrid system formed of different species introduces extra degrees of freedom that can be exploited to expand and refine the control of the system. We demonstrate an entangling gate between two atomic ions of different elements that can serve as an important building block of quantum information processing (QIP), quantum networking, precision spectroscopy, metrology, and quantum simulation. An entangling geometric phase gate between a 9 Be+ ion and a 25 Mg+ ion is realized through an effective spin-spin interaction generated by state-dependent forces. A mixed-species Bell state is thereby created with a fidelity of 0 . 979(1) . We use the gate to construct a SWAP gate that interchanges the quantum states of the two dissimilar qubits. We also report a high-fidelity universal gate set for 9 Be+ ion qubits, achieved through a combination of improved laser beam quality and control, improved state preparation, and reduced electric potential noise on trap electrodes. Supported by Office of the Director of National Intelligence (ODNI) Intelligence Advanced Research Projects Activity (IARPA), ONR, and the NIST Quantum Information Program.

  2. The cytoplasmic coiled-coil mediates cooperative gating temperature sensitivity in the voltage-gated H(+) channel Hv1.

    Science.gov (United States)

    Fujiwara, Yuichiro; Kurokawa, Tatsuki; Takeshita, Kohei; Kobayashi, Megumi; Okochi, Yoshifumi; Nakagawa, Atsushi; Okamura, Yasushi

    2012-05-08

    Hv1/VSOP is a dimeric voltage-gated H(+) channel in which the gating of one subunit is reportedly coupled to that of the other subunit within the dimer. The molecular basis for dimer formation and intersubunit coupling, however, remains unknown. Here we show that the carboxy terminus ends downstream of the S4 voltage-sensor helix twist in a dimer coiled-coil architecture, which mediates cooperative gating. We also show that the temperature-dependent activation of H(+) current through Hv1/VSOP is regulated by thermostability of the coiled-coil domain, and that this regulation is altered by mutation of the linker between S4 and the coiled-coil. Cooperative gating within the dimer is also dependent on the linker structure, which circular dichroism spectrum analysis suggests is α-helical. Our results indicate that the cytoplasmic coiled-coil strands form continuous α-helices with S4 and mediate cooperative gating to adjust the range of temperatures over which Hv1/VSOP operates.

  3. Gate stack technology for nanoscale devices

    Directory of Open Access Journals (Sweden)

    Byoung Hun Lee

    2006-06-01

    Full Text Available Scaling of the gate stack has been a key to enhancing the performance of complementary metal-oxide-semiconductor (CMOS field-effect transistors (FETs of past technology generations. Because the rate of gate stack scaling has diminished in recent years, the motivation for alternative gate stacks or novel device structures has increased considerably. Intense research during the last decade has led to the development of high dielectric constant (k gate stacks that match the performance of conventional SiO2-based gate dielectrics. However, many challenges remain before alternative gate stacks can be introduced into mainstream technology. We review the current status of and challenges in gate stack research for planar CMOS devices and alternative device technologies to provide insights for future research.

  4. Lack of conventional ATPase properties in CFTR chloride channel gating.

    Science.gov (United States)

    Schultz, B D; Bridges, R J; Frizzell, R A

    1996-05-01

    CFTR shares structural homology with the ABC transporter superfamily of proteins which hydrolyze ATP to effect the transport of compounds across cell membranes. Some superfamily members are characterized as P-type ATPases because ATP-dependent transport is sensitive to the presence of vanadate. It has been widely postulated that CFTR hydrolyzes ATP to gate its chloride channel. However, direct evidence of CFTR hydrolytic activity in channel gating is lacking and existing circumstantial evidence is contradictory. Therefore, we evaluated CFTR chloride channel activity under conditions known to inhibit the activity of ATPases; i.e., in the absence of divalent cations and in the presence of a variety of ATPase inhibitors. Removal of the cytosolic cofactor, Mg2+, reduced both the opening and closing rates of CFTR suggesting that Mg2+ plays a modulatory role in channel gating. However, channels continued to both open and close showing that Mg2+ is not an absolute requirement for channel activity. The nonselective P-type ATPase inhibitor, vanadate, did not alter the gating of CFTR when used at concentrations which completely inhibit the activity of other ABC transporters (1 mM). Higher concentrations of vanadate (10 mM) blocked the closing of CFTR, but did not affect the opening of the channel. As expected, more selective P-type (Sch28080, ouabain), V-type (bafilomycin A1, SCN-) and F-type (oligomycin) ATPase inhibitors did not affect either the opening or closing of CFTR. Thus, CFTR does not share a pharmacological inhibition profile with other ATPases and channel gating occurs in the apparent absence of hydrolysis, although with altered kinetics. Vanadate inhibition of channel closure might suggest that a hydrolytic step is involved although the requirement for a high concentration raises the possibility of previously uncharacterized effects of this compound. Most conservatively, the requirement for high concentrations of vanadate demonstrates that the binding site for

  5. Gated container molecules

    Institute of Scientific and Technical Information of China (English)

    LIU Fang; WANG Hao; HOUK K. N.

    2011-01-01

    Donald J.Cram,the great UCLA chemist,received the Nobel Prize for his discoveries about host-guest complexes [1].Both theoretical and experimental studies have been conducted about the nature and strength of interactions between the host and guest molecules.The concepts of constrictive binding (the activation energy of the binding process) and intrinsic binding (the free energy difference between the complex and the free host and guest molecules) were introduced to characterize different binding properties (Figure 1)[2].

  6. Corticolimbic gating of emotion-driven punishment.

    Science.gov (United States)

    Treadway, Michael T; Buckholtz, Joshua W; Martin, Justin W; Jan, Katharine; Asplund, Christopher L; Ginther, Matthew R; Jones, Owen D; Marois, René

    2014-09-01

    Determining the appropriate punishment for a norm violation requires consideration of both the perpetrator's state of mind (for example, purposeful or blameless) and the strong emotions elicited by the harm caused by their actions. It has been hypothesized that such affective responses serve as a heuristic that determines appropriate punishment. However, an actor's mental state often trumps the effect of emotions, as unintended harms may go unpunished, regardless of their magnitude. Using fMRI, we found that emotionally graphic descriptions of harmful acts amplify punishment severity, boost amygdala activity and strengthen amygdala connectivity with lateral prefrontal regions involved in punishment decision-making. However, this was only observed when the actor's harm was intentional; when harm was unintended, a temporoparietal-medial-prefrontal circuit suppressed amygdala activity and the effect of graphic descriptions on punishment was abolished. These results reveal the brain mechanisms by which evaluation of a transgressor's mental state gates our emotional urges to punish.

  7. Cognitive characteristics of older Japanese drivers

    Directory of Open Access Journals (Sweden)

    Susilowati Indri H

    2012-02-01

    Full Text Available Abstract Background Some causes of accidents among older drivers are: not paying attention to traffic signals; missing stop lines; and having to deal with and misjudging emergency situations. These causes of accidents reveal problems with attention and cognition. Such incidents are also related to driver perception and stress-coping mechanisms. It is important to examine the relation of stress reactions to attention and cognition as a factor influencing the causes of accidents commonly involving older drivers. Finding Subjects were 10 young drivers (23.3 ± 3.33 years and 25 older drivers divided into two groups (older1 [60 to 65 years] and older2 [> 65 years]. This study revealed the correlation within driver stress inventory and driver coping questionnaires parameters was observed only in older drivers. They also needed a longer response time for Trail Making Test A and B. The factors affected the attention and cognition of older drivers by age but not driving experience itself, and coping parameters such as emotion focus, reappraisal, and avoidance were not included as stress inventory parameters. Being prone to fatigue was less for younger drivers than older drivers. Because they have shorter distances, shorter drive times, and no need for expressways, older drivers also had a significantly lower risk of thrill-seeking behaviour and more patience. Conclusion The intervention addressing their attention skills, aggressive feelings, and emotion focus should be considered. The technological improvements in cars will make older drivers feel safer and make driving easier which might lower the attention paid to the road, and regular driving training might be needed to assess and enhance their safety.

  8. Cognitive characteristics of older Japanese drivers.

    Science.gov (United States)

    Susilowati, Indri H; Yasukouchi, Akira

    2012-02-29

    Some causes of accidents among older drivers are: not paying attention to traffic signals; missing stop lines; and having to deal with and misjudging emergency situations. These causes of accidents reveal problems with attention and cognition. Such incidents are also related to driver perception and stress-coping mechanisms. It is important to examine the relation of stress reactions to attention and cognition as a factor influencing the causes of accidents commonly involving older drivers. Subjects were 10 young drivers (23.3 ± 3.33 years) and 25 older drivers divided into two groups (older1 [60 to 65 years] and older2 [> 65 years]). This study revealed the correlation within driver stress inventory and driver coping questionnaires parameters was observed only in older drivers. They also needed a longer response time for Trail Making Test A and B. The factors affected the attention and cognition of older drivers by age but not driving experience itself, and coping parameters such as emotion focus, reappraisal, and avoidance were not included as stress inventory parameters. Being prone to fatigue was less for younger drivers than older drivers. Because they have shorter distances, shorter drive times, and no need for expressways, older drivers also had a significantly lower risk of thrill-seeking behaviour and more patience. The intervention addressing their attention skills, aggressive feelings, and emotion focus should be considered. The technological improvements in cars will make older drivers feel safer and make driving easier which might lower the attention paid to the road, and regular driving training might be needed to assess and enhance their safety.

  9. Microscale Digital Vacuum Electronic Gates

    Science.gov (United States)

    Manohara, Harish (Inventor); Mojarradi, Mohammed M. (Inventor)

    2014-01-01

    Systems and methods in accordance with embodiments of the invention implement microscale digital vacuum electronic gates. In one embodiment, a microscale digital vacuum electronic gate includes: a microscale field emitter that can emit electrons and that is a microscale cathode; and a microscale anode; where the microscale field emitter and the microscale anode are disposed within at least a partial vacuum; where the microscale field emitter and the microscale anode are separated by a gap; and where the potential difference between the microscale field emitter and the microscale anode is controllable such that the flow of electrons between the microscale field emitter and the microscale anode is thereby controllable; where when the microscale anode receives a flow of electrons, a first logic state is defined; and where when the microscale anode does not receive a flow of electrons, a second logic state is defined.

  10. Driver trust in five driver assistance technologies following real-world use in four production vehicles.

    Science.gov (United States)

    Kidd, David G; Cicchino, Jessica B; Reagan, Ian J; Kerfoot, Laura B

    2017-05-29

    Information about drivers' experiences with driver assistance technologies in real driving conditions is sparse. This study characterized driver interactions with forward collision warning, adaptive cruise control, active lane keeping, side-view assist, and lane departure warning systems following real-world use. Fifty-four Insurance Institute for Highway Safety employees participated and drove a 2016 Toyota Prius, 2016 Honda Civic, 2017 Audi Q7, or 2016 Infiniti QX60 for up to several weeks. Participants reported mileage and warnings from the technologies in an online daily-use survey. Participants reported their level of agreement with five statements regarding trust in an online post-use survey. Responses were averaged to create a composite measure of trust ranging from -2 (strongly disagree) to +2 (strongly agree) for each technology. Mixed-effect regression models were constructed to compare trust among technologies and separately among the study vehicles. Participants' free-response answers about what they liked least about each system were coded and examined. Participants reported driving 33,584 miles during 4 months of data collection. At least one forward collision warning was reported in 26% of the 354 daily reports. The proportion of daily reports indicating a forward collision warning was much larger for the Honda (70%) than for the Audi (18%), Infiniti (15%), and Toyota (10%). Trust was highest for side-view assist (0.98) and lowest for active lane keeping (0.20). Trust in side-view assist was significantly higher than trust in active lane keeping and lane departure warning (0.53). Trust in active lane keeping was significantly lower than trust in adaptive cruise control (0.67) and forward collision warning (0.71). Trust in adaptive cruise control was higher for the Audi (0.72) and Toyota (0.75) compared with the Honda (0.30), and significantly higher for the Infiniti (0.93). Trust in Infiniti's side-view assist (0.58) was significantly lower than

  11. Precise Characterization of a Laser Current Driver

    Science.gov (United States)

    Troxel, Daylin

    2009-10-01

    I will be presenting a characterization of our unique low-noise laser current driver. Our current driver improves on the typical model used in laboratories, giving extra current stability and lower noise. I will discuss our techniques for measuring the noise and drift and the results we obtained. The current driver has a lower noise and drift than any other current driver with a published value, so it has value in making precision measurements. Many other labs have expressed interest in our design as there is a need for this type of current driver in many applications. The current driver demonstrates some interesting applications of electronics principles and uses of electric components, as well as practical considerations in designing circuitry.

  12. Driver models for personalised driving assistance

    Science.gov (United States)

    Lefèvre, Stéphanie; Carvalho, Ashwin; Gao, Yiqi; Tseng, H. Eric; Borrelli, Francesco

    2015-12-01

    We propose a learning-based driver modelling approach which can identify manoeuvres performed by drivers on the highway and predict the future driver inputs. We show how this approach can be applied to provide personalised driving assistance. In a first example, the driver model is used to predict unintentional lane departures and a model predictive controller is used to keep the car in the lane. In a second example, the driver model estimates the preferred acceleration of the driver during lane keeping, and a model predictive controller is implemented to provide a personalised adaptive cruise control. For both applications, we use a combination of real data and simulation to evaluate the proposed approaches.

  13. Modal gating of muscle nicotinic acetylcholine receptors

    Science.gov (United States)

    Vij, Ridhima

    Many ion channels exhibit multiple patterns of kinetic activity in single-channel currents. This behavior is rare in WT mouse muscle nicotinic acetylcholine receptors (AChRs), where A2C↔A2O gating events are well-described by single exponentials. Also, single-channel open probability (PO) is essentially homogeneous at a given agonist concentration in the WT receptors. Here I report that perturbations of almost all the residues in loop C (alpha188-alpha199, at the agonist binding site) generate heterogeneity in PO ('modes'). Such unsettled activity was apparent with an alanine substitution at all positions in loop C (except alphaY190 and alphaY198) and with different side chain substitutions at alphaP197 for both adult- and fetal-type AChRs. I used single channel electrophysiology along with site-directed mutagenesis to study modal gating in AChRs consequent to mutations/deletions in loop C. The multiple patterns of kinetic activity arose from the difference in agonist affinity rather than in intrinsic AChR gating. Out of the four different agonists used to study the modal behavior, acetylcholine (ACh) showed a higher degree of kinetic heterogeneity compared to others. The time constant for switching between modes was long (~mins), suggesting that they arise from alternative, stable protein conformations. By studying AChRs having only 1 functional binding site, I attempted to find the source of the affinity difference, which was traced mainly to the alphadelta agonist site. Affinity at the neurotransmitter binding site is mainly determined by a core of five aromatic residues (alphaY93, alphaW149, alphaY190, alphaY198 and deltaW57). Phenylalanine substitutions at all aromatic residues except alphaY93 resulted in elimination of modes. Modes were also eliminated by alanine mutation at deltaW57 on the complementary side but not at other aromatics. Also, by substituting four gamma subunit residues into the delta subunit on the complementary beta sheet, I found that

  14. Modelling Driver Assitance Systems by Optimal Control

    OpenAIRE

    Wang, M.; Daamen, W.; Hoogendoorn, S.P.; Van Arem, B.

    2012-01-01

    Driver assistance systems support drivers in operating vehicles in a safe, comfortable and efficient way, and thus may induce changes in traffic flow characteristics. This paper put forward a receding horizon control framework to model driver assistance systems. The accelerations of automated vehicles are determined to optimise a cost function, assuming other vehicles driving at stationary conditions over a prediction horizon. The flexibility of the framework is demonstrated with controller d...

  15. Driver assistance for automatic parking; Fahrerassistenz zum automatischen Parken

    Energy Technology Data Exchange (ETDEWEB)

    Schanz, A. [DaimlerChrysler AG, Esslingen (Germany). Abt. Research E/E and Information Technologies]|[Siegen Univ. (Germany). Inst. fuer Echtzeitlernsysteme

    2005-07-01

    In the future, driver assistance systems will continue to grow in importance in automobile manufacture. Car safety and comfort can be increased through their use. The increasing availability of by-wire technologies supports this trend. By complementing these technologies with environment-encompassing sensor systems, such as video, ultrasound or laser scanners, it is possible to realize further-reaching assistance functions. By means of interactions between high-performance software and computer hardware, it is now possible to inform, warn and even actively support the driver. Parking in parking spaces, along the side of the road, at home in the garage or in parking garages and subterranean garages is often a stressful activity. For this reason, the automobile industry has offered systems for a fairly long time which assist the driver in parking. Informational and active systems are currently available. The so-called parking assistance system is among the purely informational systems. By means of optical and acoustical signals, it warns the driver if the distance to an obstacle is too small. There is already a system available on the market which supports the driver during parking by means of a human-machine interface (HMI). The expected movement is calculated from the current steering angle. This is displayed in the camera image of a rear-area camera. This thesis presents an assistance system for automatic parking. A prototype autonomous parking concept was successfully implemented. A new sensor concept for environmental data acquisition and s system concept that realizes several typical parking scenarios is realized. This complete concept has been tested and demonstrated. (orig.)

  16. The position of the fast-inactivation gate during lidocaine block of voltage-gated Na+ channels.

    Science.gov (United States)

    Vedantham, V; Cannon, S C

    1999-01-01

    Lidocaine produces voltage- and use-dependent inhibition of voltage-gated Na+ channels through preferential binding to channel conformations that are normally populated at depolarized potentials and by slowing the rate of Na+ channel repriming after depolarizations. It has been proposed that the fast-inactivation mechanism plays a crucial role in these processes. However, the precise role of fast inactivation in lidocaine action has been difficult to probe because gating of drug-bound channels does not involve changes in ionic current. For that reason, we employed a conformational marker for the fast-inactivation gate, the reactivity of a cysteine substituted at phenylalanine 1304 in the rat adult skeletal muscle sodium channel alpha subunit (rSkM1) with [2-(trimethylammonium)ethyl]methanethiosulfonate (MTS-ET), to determine the position of the fast-inactivation gate during lidocaine block. We found that lidocaine does not compete with fast-inactivation. Rather, it favors closure of the fast-inactivation gate in a voltage-dependent manner, causing a hyperpolarizing shift in the voltage dependence of site 1304 accessibility that parallels a shift in the steady state availability curve measured for ionic currents. More significantly, we found that the lidocaine-induced slowing of sodium channel repriming does not result from a slowing of recovery of the fast-inactivation gate, and thus that use-dependent block does not involve an accumulation of fast-inactivated channels. Based on these data, we propose a model in which transitions along the activation pathway, rather than transitions to inactivated states, play a crucial role in the mechanism of lidocaine action.

  17. High Radiation Tolerant Ceramic Voltage Isolator (Non-optical Gate Driver) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of the Phase I effort is to design, develop and demonstrate a novel solid-state ceramic-based voltage isolator and demonstrate its potential to provide a...

  18. Economic drivers of mineral supply

    Science.gov (United States)

    Wagner, Lorie A.; Sullivan, Daniel E.; Sznopek, John L.

    2003-01-01

    The debate over the adequacy of future supplies of mineral resources continues in light of the growing use of mineral-based materials in the United States. According to the U.S. Geological Survey, the quantity of new materials utilized each year has dramatically increased from 161 million tons2 in 1900 to 3.2 billion tons in 2000. Of all the materials used during the 20th century in the United States, more than half were used in the last 25 years. With the Earth?s endowment of natural resources remaining constant, and increased demand for resources, economic theory states that as depletion approaches, prices rise. This study shows that many economic drivers (conditions that create an economic incentive for producers to act in a particular way) such as the impact of globalization, technological improvements, productivity increases, and efficient materials usage are at work simultaneously to impact minerals markets and supply. As a result of these economic drivers, the historical price trend of mineral prices3 in constant dollars has declined as demand has risen. When price is measured by the cost in human effort, the price trend also has been almost steadily downward. Although the United States economy continues its increasing mineral consumption trend, the supply of minerals has been able to keep pace. This study shows that in general supply has grown faster than demand, causing a declining trend in mineral prices.

  19. Drivers of Ecological Restoration: Lessons from a Century of Restoration in Iceland

    Directory of Open Access Journals (Sweden)

    Ása L. Aradóttir

    2013-12-01

    Full Text Available We analyzed the main drivers for ecological restoration in Iceland from 1907 to 2010 and assessed whether the drivers have changed over time and what factors might explain the changes, if any. Our study was based on a catalogue of 100 restoration projects, programs, and areas, representing 75% to 85% of all restoration activities in Iceland. Catastrophic erosion was an early driver for soil conservation and restoration efforts that still ranked high in the 2000s, reflecting the immense scale of soil erosion and desertification in Iceland. Socioeconomic drivers such as farming and the provision of wood products were strong motivators of ecological restoration over most of the 20th century, although their relative importance decreased with time as the number and diversity of drivers increased. In the 1960s and 1970s, the construction of hard infrastructure, and moral values such as improving the aesthetics of the countryside and "repaying the debt to the land" emerged as motivations for restoration actions. In the late 1990s, the United Nations Climate Change Convention became a driver for restoration, and the importance of nature conservation and recreation increased. Technological development and financial incentives did not show up as drivers of ecological restoration in our study, although there are some indications of their influence. Furthermore, policy was a minor driver, which might reflect weak policy instruments for ecological restoration and some counteractive policies.

  20. Steering disturbance rejection using a physics-based neuromusculoskeletal driver model

    Science.gov (United States)

    Mehrabi, Naser; Sharif Razavian, Reza; McPhee, John

    2015-10-01

    The aim of this work is to develop a comprehensive yet practical driver model to be used in studying driver-vehicle interactions. Drivers interact with their vehicle and the road through the steering wheel. This interaction forms a closed-loop coupled human-machine system, which influences the driver's steering feel and control performance. A hierarchical approach is proposed here to capture the complexity of the driver's neuromuscular dynamics and the central nervous system in the coordination of the driver's upper extremity activities, especially in the presence of external disturbance. The proposed motor control framework has three layers: the first (or the path planning) plans a desired vehicle trajectory and the required steering angles to perform the desired trajectory; the second (or the musculoskeletal controller) actuates the musculoskeletal arm to rotate the steering wheel accordingly; and the final layer ensures the precision control and disturbance rejection of the motor control units. The physics-based driver model presented here can also provide insights into vehicle control in relaxed and tensed driving conditions, which are simulated by adjusting the driver model parameters such as cognition delay and muscle co-contraction dynamics.

  1. Reversible logic gate using adiabatic superconducting devices

    Science.gov (United States)

    Takeuchi, N.; Yamanashi, Y.; Yoshikawa, N.

    2014-09-01

    Reversible computing has been studied since Rolf Landauer advanced the argument that has come to be known as Landauer's principle. This principle states that there is no minimum energy dissipation for logic operations in reversible computing, because it is not accompanied by reductions in information entropy. However, until now, no practical reversible logic gates have been demonstrated. One of the problems is that reversible logic gates must be built by using extremely energy-efficient logic devices. Another difficulty is that reversible logic gates must be both logically and physically reversible. Here we propose the first practical reversible logic gate using adiabatic superconducting devices and experimentally demonstrate the logical and physical reversibility of the gate. Additionally, we estimate the energy dissipation of the gate, and discuss the minimum energy dissipation required for reversible logic operations. It is expected that the results of this study will enable reversible computing to move from the theoretical stage into practical usage.

  2. System and Method for Scan Range Gating

    Science.gov (United States)

    Zuk, David M. (Inventor); Lindemann, Scott (Inventor)

    2017-01-01

    A system for scanning light to define a range gated signal includes a pulsed coherent light source that directs light into the atmosphere, a light gathering instrument that receives the light modified by atmospheric backscatter and transfers the light onto an image plane, a scanner that scans collimated light from the image plane to form a range gated signal from the light modified by atmospheric backscatter, a control circuit that coordinates timing of a scan rate of the scanner and a pulse rate of the pulsed coherent light source so that the range gated signal is formed according to a desired range gate, an optical device onto which an image of the range gated signal is scanned, and an interferometer to which the image of the range gated signal is directed by the optical device. The interferometer is configured to modify the image according to a desired analysis.

  3. Cognitive mechanisms associated with auditory sensory gating.

    Science.gov (United States)

    Jones, L A; Hills, P J; Dick, K M; Jones, S P; Bright, P

    2016-02-01

    Sensory gating is a neurophysiological measure of inhibition that is characterised by a reduction in the P50 event-related potential to a repeated identical stimulus. The objective of this work was to determine the cognitive mechanisms that relate to the neurological phenomenon of auditory sensory gating. Sixty participants underwent a battery of 10 cognitive tasks, including qualitatively different measures of attentional inhibition, working memory, and fluid intelligence. Participants additionally completed a paired-stimulus paradigm as a measure of auditory sensory gating. A correlational analysis revealed that several tasks correlated significantly with sensory gating. However once fluid intelligence and working memory were accounted for, only a measure of latent inhibition and accuracy scores on the continuous performance task showed significant sensitivity to sensory gating. We conclude that sensory gating reflects the identification of goal-irrelevant information at the encoding (input) stage and the subsequent ability to selectively attend to goal-relevant information based on that previous identification.

  4. Electrostatically gated membrane permeability in inorganic protocells

    Science.gov (United States)

    Li, Mei; Harbron, Rachel L.; Weaver, Jonathan V. M.; Binks, Bernard P.; Mann, Stephen

    2013-06-01

    Although several strategies are now available to produce functional microcompartments analogous to primitive cell-like structures, little progress has been made in generating protocell constructs with self-controlled membrane permeability. Here we describe the preparation of water-dispersible colloidosomes based on silica nanoparticles and delineated by a continuous semipermeable inorganic membrane capable of self-activated, electrostatically gated permeability. We use crosslinking and covalent grafting of a pH-responsive copolymer to generate an ultrathin elastic membrane that exhibits selective release and uptake of small molecules. This behaviour, which depends on the charge of the copolymer coronal layer, serves to trigger enzymatic dephosphorylation reactions specifically within the protocell aqueous interior. This system represents a step towards the design and construction of alternative types of artificial chemical cells and protocell models based on spontaneous processes of inorganic self-organization.

  5. Gate-controlled conductance switching in DNA

    Science.gov (United States)

    Xiang, Limin; Palma, Julio L.; Li, Yueqi; Mujica, Vladimiro; Ratner, Mark A.; Tao, Nongjian

    2017-02-01

    Extensive evidence has shown that long-range charge transport can occur along double helical DNA, but active control (switching) of single-DNA conductance with an external field has not yet been demonstrated. Here we demonstrate conductance switching in DNA by replacing a DNA base with a redox group. By applying an electrochemical (EC) gate voltage to the molecule, we switch the redox group between the oxidized and reduced states, leading to reversible switching of the DNA conductance between two discrete levels. We further show that monitoring the individual conductance switching allows the study of redox reaction kinetics and thermodynamics at single molecular level using DNA as a probe. Our theoretical calculations suggest that the switch is due to the change in the energy level alignment of the redox states relative to the Fermi level of the electrodes.

  6. Designing quantum gates using the genetic algorithm

    Science.gov (United States)

    Kumar, Karthikeyan S.; Paraoanu, G. S.

    2012-12-01

    We demonstrate the usage of Genetic Algorithm (GA) to tailor the radio frequency pulses for producing unitary transformations in qubit systems. We find that the initial population converges to the optimal solution after 10 generations, for a one segment pulse corresponding to single qubit Hadamard gate. For a two qubit CNOT gate, we see the population convergence for a two segment pulse after 150 generations. This demonstrates that the method is suitable for designing quantum gates.

  7. Floating gate transistors as biosensors (Conference Presentation)

    Science.gov (United States)

    Frisbie, C. Daniel

    2016-11-01

    Electrolyte gated transistors (EGTs) are a sub-class of thin film transistors that are extremely promising for biological sensing applications. These devices employ a solid electrolyte as the gate insulator; the very large capacitance of the electrolyte results in low voltage operation and high transconductance or gain. This talk will describe the fabrication of floating gate EGTs and their use as ricin sensors. The critical performance metrics for EGTs compared with other types of TFTs will also be reviewed.

  8. Bubbles, Gating, and Anesthetics in Ion Channels

    OpenAIRE

    Roth, Roland, imp.; Gillespie, Dirk; Nonner, Wolfgang; Eisenberg, Robert E.

    2008-01-01

    We suggest that bubbles are the bistable hydrophobic gates responsible for the on-off transitions of single channel currents. In this view, many types of channels gate by the same physical mechanism—dewetting by capillary evaporation—but different types of channels use different sensors to modulate hydrophobic properties of the channel wall and thereby trigger and control bubbles and gating. Spontaneous emptying of channels has been seen in many simulations. Because of the physics involved, s...

  9. Criteria for universality of quantum gates

    Science.gov (United States)

    Sawicki, Adam; Karnas, Katarzyna

    2017-06-01

    We consider the problem of deciding if a set of quantum one-qudit gates S ={U1,...,Un} is universal. We provide the compact-form criteria leading to a simple algorithm that allows deciding the universality of any given set of gates in a finite number of steps. Moreover, for a nonuniversal S our criteria indicate what types of gates can be added to S to turn it into a universal set.

  10. Voltage gating by molecular subunits of Na+ and K+ ion channels: higher-dimensional cubic kinetics, rate constants, and temperature.

    Science.gov (United States)

    Fohlmeister, Jürgen F

    2015-06-01

    The structural similarity between the primary molecules of voltage-gated Na and K channels (alpha subunits) and activation gating in the Hodgkin-Huxley model is brought into full agreement by increasing the model's sodium kinetics to fourth order (m(3) → m(4)). Both structures then virtually imply activation gating by four independent subprocesses acting in parallel. The kinetics coalesce in four-dimensional (4D) cubic diagrams (16 states, 32 reversible transitions) that show the structure to be highly failure resistant against significant partial loss of gating function. Rate constants, as fitted in phase plot data of retinal ganglion cell excitation, reflect the molecular nature of the gating transitions. Additional dimensions (6D cubic diagrams) accommodate kinetically coupled sodium inactivation and gating processes associated with beta subunits. The gating transitions of coupled sodium inactivation appear to be thermodynamically irreversible; response to dielectric surface charges (capacitive displacement) provides a potential energy source for those transitions and yields highly energy-efficient excitation. A comparison of temperature responses of the squid giant axon (apparently Arrhenius) and mammalian channel gating yields kinetic Q10 = 2.2 for alpha unit gating, whose transitions are rate-limiting at mammalian temperatures; beta unit kinetic Q10 = 14 reproduces the observed non-Arrhenius deviation of mammalian gating at low temperatures; the Q10 of sodium inactivation gating matches the rate-limiting component of activation gating at all temperatures. The model kinetics reproduce the physiologically large frequency range for repetitive firing in ganglion cells and the physiologically observed strong temperature dependence of recovery from inactivation. Copyright © 2015 the American Physiological Society.

  11. Integrin receptors and ligand-gated channels.

    Science.gov (United States)

    Morini, Raffaella; Becchetti, Andrea

    2010-01-01

    Plastic expression of different integrin subunits controls the different stages of neural development, whereas in the adult integrins regulate synaptic stability. Evidence of integrin-channel crosstalk exists for ionotropic glutamate receptors. As is often the case in other tissues, integrin engagement regulates channel activity through complex signaling pathways that often include tyrosine phosphorylation cascades. The specific pathways recruited by integrin activation depend on cerebral region and cell type. In turn, ion channels control integrin expression onto the plasma membrane and their ligand binding affinity. The most extensive studies concern the hippocampus and suggest implications for neuronal circuit plasticity. The physiological relevance of these findings depends on whether adhesion molecules, aside from determining tissue stability, contribute to synaptogenesis and the responsiveness of mature synapses, thus contributing to long-term circuit consolidation. Little evidence is available for other ligand-gated channels, with the exception of nicotinic receptors. These exert a variety of functions in neurons and non neural tissue, both in development and in the adult, by regulating cell cycle, synaptogenesis and synaptic circuit refinement. Detailed studies in epidermal keratinocytes have shed some light on the possible mechanisms through which ACh can regulate cell motility, which may be of general relevance for morphogenetic processes. As to the control of mature synapses, most results concern the integrinic control of nicotinic receptors in the neuromuscular junction. Following this lead, a few studies have addressed similar topics in adult cerebral synapses. However, pursuing and interpreting these results in the brain is especially difficult because of the complexity of the nicotinic roles and the widespread contribution of nonsynaptic, paracrine transmission. From a pathological point of view, considering the well-known contribution of both

  12. Circuits with arbitrary gates for random operators

    CERN Document Server

    Jukna, S

    2010-01-01

    We consider boolean circuits computing n-operators f:{0,1}^n --> {0,1}^n. As gates we allow arbitrary boolean functions; neither fanin nor fanout of gates is restricted. An operator is linear if it computes n linear forms, that is, computes a matrix-vector product y=Ax over GF(2). We prove the existence of n-operators requiring about n^2 wires in any circuit, and linear n-operators requiring about n^2/\\log n wires in depth-2 circuits, if either all output gates or all gates on the middle layer are linear.

  13. Design and Construction of Toll Gate Control System Based On Microcontroller

    Directory of Open Access Journals (Sweden)

    Yin Mon Aye

    2014-10-01

    Full Text Available Electronic Toll Gate Station is the system which is implemented to automatically a more convenient way of collecting the toll and traffic management. There are millions of drivers passing through the toll gate station every day. Most of the toll collection systems commonly used in Myanmar is manual transaction. This paper describes a new method for toll collection system according to the weight of the vehicles. This electronic toll gate collection system has been fabricated based on microcontroller. The purpose of this work is to collect toll according to the weight of vehicle. There are three portions in toll collection system. They are the weight scales sub-system, Graphic User Interface (GUI in the host computer and the motor driving circuit for barricade control system. The authorized person at the toll gate can check the ID numbers, vehicle numbers, type of vehicle and the amount of balance via GUI on PC. The PIC microcontroller is also used to control the DC motor and display the weight on the LCD. For software implementation, visual basic programming language is used.

  14. Gated Graphene Electrical Transport Characterization

    Directory of Open Access Journals (Sweden)

    Josef Náhlík

    2012-01-01

    Full Text Available Graphene is a very interesting new material, and promises attractive applications in future nanodevices. It is a 2D carbon structure with very interesting physical behavior. Graphene is an almost transparent material that has higher carrier mobility than any other material at room temperature. Graphene can therefore be used in applications such as ultrahigh-speed transistors and transparent electrodes. In this paper, we present our preliminary experiments on the transport behavior of graphene at room temperature. We measured the resistivity of Hall-bar samples depending on gate voltage (backgated graphene. Hysteresis between the forward and backward sweep direction was observed.

  15. Implicit-OR tiling of deoxyribozymes: Construction of molecular scale OR, NAND, and four-input logic gates

    Directory of Open Access Journals (Sweden)

    DARKO STEFANOVIC

    2003-05-01

    Full Text Available We recently reported the first complete set of molecular-scale logic gates based on deoxyribozymes. Here we report how we tile these logic gates and construct new logic elements: OR, NAND, and the first element with four inputs (i1^i5Ú(i2^i6. Tiling of logic gates was achieved through a common substrate used for core deoxyribozyme; degradation of this substrate defines the output. This kind of connection between logic gates is an implicit-OR tiling, because it suffices that one componenet of the network is active for the whole network to give an output of 1.

  16. Less-Conventional Low-Consumption Galvanic Separated MOSFET-IGBT Gate Drive Supply

    Directory of Open Access Journals (Sweden)

    Jean Marie Vianney Bikorimana

    2017-01-01

    Full Text Available A simple half-bridge, galvanic separated power supply which can be short circuit proof is proposed for gate driver local supplies. The supply is made while hacking a common mode type filter as a transformer, as the transformer shows a good insulation, it has a very low parasitic capacitance between primary and secondary coils, and it is cost-effective. Very low standby losses were observed during lab experiments. This makes it compatible with energy efficient drives and solar inverters.

  17. Developing Linux kernel space device driver

    Institute of Scientific and Technical Information of China (English)

    Zheng Wei; Wang Qinruo; Wu Naiyou

    2003-01-01

    This thesis introduces how to develop kernel level device drivers on Linux platform in detail. On the basis of comparing proc file system with dev file system, we choose PCI devices and USB devices as instances to introduce the method of writing device drivers for character devices by using these two file systems.

  18. Should Passengers Be Responsible For Drunk Drivers?

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In late September, China’s Ministry of Public Security expanded its nationwide campaign against drunk driving by releasing a document suggesting that passengers sharing a car with a drunk driver be punished together with the driver and that passengers who do not prevent drunk driving be fined.

  19. Frictional Dermatosis in a Courier Driver

    Directory of Open Access Journals (Sweden)

    Uwe Wollina

    2017-07-01

    Full Text Available Frictional hypermelanosis is an uncommon finding in Caucasians. We report the unusual case of 56-year-old male courier driver who developed linear and patchy hypermelanosis of the back caused by the driver's seat. Histology has included other pathologies. Treatment of the asymptomatic hyper pigmentation was not warranted.

  20. Physics at an upgraded Fermilab proton driver

    Energy Technology Data Exchange (ETDEWEB)

    Geer, S.; /Fermilab

    2005-07-01

    In 2004 the Fermilab Long Range Planning Committee identified a new high intensity Proton Driver as an attractive option for the future, primarily motivated by the recent exciting developments in neutrino physics. Over the last few months a physics study has developed the physics case for the Fermilab Proton Driver. The potential physics opportunities are discussed.

  1. Physics at an upgraded Fermilab proton driver

    Energy Technology Data Exchange (ETDEWEB)

    Geer, S.; /Fermilab

    2005-07-01

    In 2004 the Fermilab Long Range Planning Committee identified a new high intensity Proton Driver as an attractive option for the future, primarily motivated by the recent exciting developments in neutrino physics. Over the last few months a physics study has developed the physics case for the Fermilab Proton Driver. The potential physics opportunities are discussed.

  2. 49 CFR 177.816 - Driver training.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Driver training. 177.816 Section 177.816... Information and Regulations § 177.816 Driver training. (a) In addition to the training requirements of § 177... employee who will operate a motor vehicle has been trained in the applicable requirements of 49 CFR...

  3. Displaceable Gear Torque Controlled Driver

    Science.gov (United States)

    Cook, Joseph S., Jr. (Inventor)

    1997-01-01

    Methods and apparatus are provided for a torque driver including a displaceable gear to limit torque transfer to a fastener at a precisely controlled torque limit. A biasing assembly biases a first gear into engagement with a second gear for torque transfer between the first and second gear. The biasing assembly includes a pressurized cylinder controlled at a constant pressure that corresponds to a torque limit. A calibrated gage and valve is used to set the desired torque limit. One or more coiled output linkages connect the first gear with the fastener adaptor which may be a socket for a nut. A gear tooth profile provides a separation force that overcomes the bias to limit torque at the desired torque limit. Multiple fasteners may be rotated simultaneously to a desired torque limit if additional output spur gears are provided. The torque limit is adjustable and may be different for fasteners within the same fastener configuration.

  4. The drivers of plant diversity

    DEFF Research Database (Denmark)

    Jensen, Kristine Engemann

    In this thesis we use a “big data” approach to describe and explain large-scale patterns of plant diversity. The botanical data used for the six papers come from three different databases covering the New World, North America, and Europe respectively. The data on plant distributions were combined...... and beta diversity over time for woody forest communities in North America, using a 20 year forest plot dataset from the United States Department of Agriculture Forest Inventory and Analysis program. To assess functional diversity, we combined the plot data with data on four functional traits. Over time...... with environmental data on climate, soil, topography, and disturbance to identify the drivers of macroecological plant diversity patterns. Unless otherwise stated, the botanical data used in the papers come from the Botanical Information and Ecology Network. Paper I describes how we compiled a new plant growth form...

  5. BDC 500 branch driver controller

    CERN Document Server

    Dijksman, A

    1981-01-01

    This processor has been designed for very fast data acquisition and date pre-processing. The dataway and branch highway speeds have been optimized for approximately 1.5 mu sec. The internal processor cycle is approximately 0.8 mu sec. The standard version contains the following functions (slots): crate controller type A1; branch highway driver including terminator; serial I/O port (TTY, VDU); 24 bit ALU and 24 bit program counter; 16 bit memory address counter and 4 word stack; 4k bit memory for program and/or data; battery backup for the memory; CNAFD and crate LAM display; request/grant logic for time- sharing operation of several BDCs. The free slots can be equipped with e.g. extra RAM, computer interfaces, hardware multiplier/dividers, etc. (0 refs).

  6. Visual behaviour analysis and driver cognitive model

    Energy Technology Data Exchange (ETDEWEB)

    Baujon, J.; Basset, M.; Gissinger, G.L. [Mulhouse Univ., (France). MIPS/MIAM Lab.

    2001-07-01

    Recent studies on driver behaviour have shown that perception - mainly visual but also proprioceptive perception - plays a key role in the ''driver-vehicle-road'' system and so considerably affects the driver's decision making. Within the framework of the behaviour analysis and studies low-cost system (BASIL), this paper presents a correlative, qualitative and quantitative study, comparing the information given by visual perception and by the trajectory followed. This information will help to obtain a cognitive model of the Rasmussen type according to different driver classes. Many experiments in real driving situations have been carried out for different driver classes and for a given trajectory profile, using a test vehicle and innovative, specially designed, real-time tools, such as the vision system or the positioning module. (orig.)

  7. Stability analysis of automobile driver steering control

    Science.gov (United States)

    Allen, R. W.

    1981-01-01

    In steering an automobile, the driver must basically control the direction of the car's trajectory (heading angle) and the lateral deviation of the car relative to a delineated pathway. A previously published linear control model of driver steering behavior which is analyzed from a stability point of view is considered. A simple approximate expression for a stability parameter, phase margin, is derived in terms of various driver and vehicle control parameters, and boundaries for stability are discussed. A field test study is reviewed that includes the measurement of driver steering control parameters. Phase margins derived for a range of vehicle characteristics are found to be generally consistent with known adaptive properties of the human operator. The implications of these results are discussed in terms of driver adaptive behavior.

  8. Comparative study of the gating motif and C-type inactivation in prokaryotic voltage-gated sodium channels.

    Science.gov (United States)

    Irie, Katsumasa; Kitagawa, Kazuya; Nagura, Hitoshi; Imai, Tomoya; Shimomura, Takushi; Fujiyoshi, Yoshinori

    2010-02-05

    Prokaryotic voltage-gated sodium channels (Na(V)s) are homotetramers and are thought to inactivate through a single mechanism, named C-type inactivation. Here we report the voltage dependence and inactivation rate of the NaChBac channel from Bacillus halodurans, the first identified prokaryotic Na(V), as well as of three new homologues cloned from Bacillus licheniformis (Na(V)BacL), Shewanella putrefaciens (Na(V)SheP), and Roseobacter denitrificans (Na(V)RosD). We found that, although activated by a lower membrane potential, Na(V)BacL inactivates as slowly as NaChBac. Na(V)SheP and Na(V)RosD inactivate faster than NaChBac. Mutational analysis of helix S6 showed that residues corresponding to the "glycine hinge" and "PXP motif" in voltage-gated potassium channels are not obligatory for channel gating in these prokaryotic Na(V)s, but mutations in the regions changed the inactivation rates. Mutation of the region corresponding to the glycine hinge in Na(V)BacL (A214G), Na(V)SheP (A216G), and NaChBac (G219A) accelerated inactivation in these channels, whereas mutation of glycine to alanine in the lower part of helix S6 in NaChBac (G229A), Na(V)BacL (G224A), and Na(V)RosD (G217A) reduced the inactivation rate. These results imply that activation gating in prokaryotic Na(V)s does not require gating motifs and that the residues of helix S6 affect C-type inactivation rates in these channels.

  9. Ambipolar organic thin-film transistor-based nano-floating-gate nonvolatile memory

    Energy Technology Data Exchange (ETDEWEB)

    Han, Jinhua; Wang, Wei, E-mail: wwei99@jlu.edu.cn; Ying, Jun; Xie, Wenfa [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012 (China)

    2014-01-06

    An ambipolar organic thin-film transistor-based nano-floating-gate nonvolatile memory was demonstrated, with discrete distributed gold nanoparticles, tetratetracontane (TTC), pentacene as the floating-gate layer, tunneling layer, and active layer, respectively. The electron traps at the TTC/pentacene interface were significantly suppressed, which resulted in an ambipolar operation in present memory. As both electrons and holes were supplied in the channel and trapped in the floating-gate by programming/erasing operations, respectively, i.e., one type of charge carriers was used to overwrite the other, trapped, one, a large memory window, extending on both sides of the initial threshold voltage, was realized.

  10. Nonintegral stoichiometry in CFTR gating revealed by a pore-lining mutation

    OpenAIRE

    Jih, Kang-Yang; Sohma, Yoshiro; Hwang, Tzyh-Chang

    2012-01-01

    Cystic fibrosis transmembrane conductance regulator (CFTR) is a unique member of the ATP-binding cassette (ABC) protein superfamily. Unlike most other ABC proteins that function as active transporters, CFTR is an ATP-gated chloride channel. The opening of CFTR’s gate is associated with ATP-induced dimerization of its two nucleotide-binding domains (NBD1 and NBD2), whereas gate closure is facilitated by ATP hydrolysis-triggered partial separation of the NBDs. This generally held theme of CFTR ...

  11. A single high dose of escitalopram disrupts sensory gating and habituation, but not sensorimotor gating in healthy volunteers

    DEFF Research Database (Denmark)

    Oranje, Bob; Wienberg, Malene; Glenthøj, Birte Yding

    2011-01-01

    Early mechanisms to limit the input of sensory information to higher brain areas are important for a healthy individual. In previous studies, we found that a low dose of 10mg escitalopram (SSRI) disrupts habituation, without affecting sensory and sensorimotor gating in healthy volunteers. In the ......Early mechanisms to limit the input of sensory information to higher brain areas are important for a healthy individual. In previous studies, we found that a low dose of 10mg escitalopram (SSRI) disrupts habituation, without affecting sensory and sensorimotor gating in healthy volunteers....... In the current study a higher dose of 15mg was used. The hypothesis was that this higher dose of escitalopram would not only disrupt habituation, but also sensory and sensorimotor gating. Twenty healthy male volunteers received either placebo or 15mg escitalopram, after which they were tested in a P50...... suppression, and a habituation and prepulse inhibition (PPI) of the startle reflex paradigm. Escitalopram significantly decreased P50 suppression and habituation, but had no effect on PPI. The results indicate that habituation and sensory gating are disrupted by increased serotonergic activity, while...

  12. Truck drivers, middlemen and commercial sex workers: AIDS and the mediation of sex in south west Uganda.

    Science.gov (United States)

    Gysels, M; Pool, R; Bwanika, K

    2001-06-01

    Although long distance truck drivers have been implicated in the spread of HIV in Africa, there is a paucity of studies of their sexual cultures. This paper reports on a study of the sexual culture of drivers, mediators and commercial sex workers (CSWs) in a roadside truck stop on the Trans-Africa highway in south west Uganda. Sixty-nine truck drivers, six middlemen and 12 CSWs were interviewed using semi-structured questionnaires. Interviewing truck drivers also entailed participating in the town's nightlife and spending much time in the bars. Truck drivers stop briefly at the truck stop for various reasons: to eat, sleep, have sex and sell goods they are carrying. Middlemen mediate the latter two activities. Middlemen buy goods from the drivers and introduce them to 'suitable' women with whom they can have casual sex. Most drivers have sex when they spend the night at the truck stop, and most make use of the services of the middlemen. The most important reasons why drivers use middlemen are that the latter speak the local languages and, in particular, know the trustworthy and 'safe' (HIV-negative) women. The CSWs use middlemen mainly because they are a guarantee that the driver will pay and they usually ensure that drivers pay well. The mediation system is becoming increasingly professionalized. Most drivers claimed to use condoms during casual sex, and this was confirmed by the CSWs. General use of condoms is encouraging, particularly given the context of a culture generally opposed to condoms. The idea that middlemen can recognize 'safe' women is worrying. However, given their key position, middlemen could form the hub of an opinion leader type intervention focused on drivers and the professional group of sex workers described here, providing condoms, advising about the importance of condom use in all casual sexual encounters, giving information about HIV and STDs, and possibly referring drivers and women to appropriate sources of HIV counselling and testing

  13. Reducing risky driver behaviour through the implementation of a driver risk management system

    Directory of Open Access Journals (Sweden)

    Rose Luke

    2014-03-01

    Full Text Available South Africa has one of the highest incidences of road accidents in the world. Most accidents are avoidable and are caused by driver behaviour and errors. The purpose of this article was to identify the riskiest driver behaviours in commercial fleets in South Africa, to determine the business impact of such behaviour, to establish a framework for the management of risky driver behaviour and to test the framework by applying a leading commercial driver behaviour management system as a case study. The case study comprised three South African commercial fleets. Using data from these fleets, critical incident triangles were used to determine the ratio data of risky driver behaviour to near-collisions and collisions. Based on managing the riskiest driver behaviours as causes of more serious incidents and accidents, the results indicated that through the implementation of an effective driver risk management system, risky incidents were significantly reduced.

  14. Modeling aggressive driver behavior at unsignalized intersections.

    Science.gov (United States)

    Kaysi, Isam A; Abbany, Ali S

    2007-07-01

    The processing of vehicles at unsignalized intersections is a complex and highly interactive process, whereby each driver makes individual decisions about when, where, and how to complete the required maneuver, subject to his perceptions of distances, velocities, and own car's performance. Typically, the performance of priority-unsignalized intersections has been modeled with probabilistic approaches that consider the distribution of gaps in the major-traffic stream and their acceptance by the drivers of minor street vehicles based on the driver's "critical gap". This paper investigates the aggressive behavior of minor street vehicles at intersections that are priority-unsignalized but operate with little respect of control measures. The objective is to formulate a behavioral model that predicts the probability that a driver performs an aggressive maneuver as a function of a set of driver and traffic attributes. Parameters that were tested and modeled include driver characteristics (gender and age), car characteristics (performance and model year), and traffic attributes (number of rejected gaps, total waiting time at head of queue, and major-traffic speed). Binary probit models are developed and tested, based on a collected data set from an unsignalized intersection in the city of Beirut, to determine which of the studied variables are statistically significant in determining the aggressiveness of a specific driver. Primary conclusions reveal that age, car performance, and average speed on the major road are the major determinants of aggressive behavior. Another striking conclusion is that the total waiting time of the driver while waiting for an acceptable gap is of little significance in incurring the "forcing" behavior. The obtained model is incorporated in a simple simulation framework that reflects driver behavior and traffic stream interactions in estimating delay and conflict measures at unsignalized intersections. The simulation results were then compared

  15. Driver drowsiness detection using multimodal sensor fusion

    Science.gov (United States)

    Andreeva, Elena O.; Aarabi, Parham; Philiastides, Marios G.; Mohajer, Keyvan; Emami, Majid

    2004-04-01

    This paper proposes a multi-modal sensor fusion algorithm for the estimation of driver drowsiness. Driver sleepiness is believed to be responsible for more than 30% of passenger car accidents and for 4% of all accident fatalities. In commercial vehicles, drowsiness is blamed for 58% of single truck accidents and 31% of commercial truck driver fatalities. This work proposes an innovative automatic sleep-onset detection system. Using multiple sensors, the driver"s body is studied as a mechanical structure of springs and dampeners. The sleep-detection system consists of highly sensitive triple-axial accelerometers to monitor the driver"s upper body in 3-D. The subject is modeled as a linear time-variant (LTV) system. An LMS adaptive filter estimation algorithm generates the transfer function (i.e. weight coefficients) for this LTV system. Separate coefficients are generated for the awake and asleep states of the subject. These coefficients are then used to train a neural network. Once trained, the neural network classifies the condition of the driver as either awake or asleep. The system has been tested on a total of 8 subjects. The tests were conducted on sleep-deprived individuals for the sleep state and on fully awake individuals for the awake state. When trained and tested on the same subject, the system detected sleep and awake states of the driver with a success rate of 95%. When the system was trained on three subjects and then retested on a fourth "unseen" subject, the classification rate dropped to 90%. Furthermore, it was attempted to correlate driver posture and sleepiness by observing how car vibrations propagate through a person"s body. Eight additional subjects were studied for this purpose. The results obtained in this experiment proved inconclusive which was attributed to significant differences in the individual habitual postures.

  16. [Bus drivers' biomechanical risk assessment in two different contexts].

    Science.gov (United States)

    Baracco, A; Coggiola, M; Perrelli, F; Banchio, M; Martignone, S; Gullino, A; Romano, C

    2012-01-01

    The application of standardize methods for the biomechanical risk assessment in non-industrial cycled activity is not always possible. A typical case is the public transport sector, where workers complain of suffering for shoulder more than elbow and wrist pains. The Authors present the results of two studies involving two public transport companies and the risk of biomechanical overload of upper limbs for bus and tram drivers. The analysis has been made using three different approaches: focus groups; static analysis by using anthropometric manikins; work sampling technique by monitoring worker's activity and posture at each minute, for two hours and for each binomial vehicle-route, considering P5F e P95M drivers and assessing the perceived efforts thorough the Borg's CR10 Scale. The conclusive results show that the ergonomic analysis managed by multiple non-standardized techniques may reach consistent and repeatable results according to the epidemiological evidences.

  17. Nanosecond gating properties of proximity focused microchannel plate image intensifiers

    Science.gov (United States)

    King, N. S. P.; King, N. S. P.; Yates, G. J.; Jaramillo, S. A.; Noel, B. W.; Detch, J. L., Jr.; Ogle, J. W.

    The optical gating properties of Multichannel plate image intensifiers were characterized. Emphasis was placed on parameters relevant to gating speed and correlations between the applied electrical and resultant optical gates.

  18. Transparently wrap-gated semiconductor nanowire arrays for studies of gate-controlled photoluminescence

    Energy Technology Data Exchange (ETDEWEB)

    Nylund, Gustav; Storm, Kristian; Torstensson, Henrik; Wallentin, Jesper; Borgström, Magnus T.; Hessman, Dan; Samuelson, Lars [Solid State Physics, Nanometer Structure Consortium, Lund University, Box 118, S-221 00 Lund (Sweden)

    2013-12-04

    We present a technique to measure gate-controlled photoluminescence (PL) on arrays of semiconductor nanowire (NW) capacitors using a transparent film of Indium-Tin-Oxide (ITO) wrapping around the nanowires as the gate electrode. By tuning the wrap-gate voltage, it is possible to increase the PL peak intensity of an array of undoped InP NWs by more than an order of magnitude. The fine structure of the PL spectrum reveals three subpeaks whose relative peak intensities change with gate voltage. We interpret this as gate-controlled state-filling of luminescing quantum dot segments formed by zincblende stacking faults in the mainly wurtzite NW crystal structure.

  19. Essential function of the N-termini tails of the proteasome for the gating mechanism revealed by molecular dynamics simulations.

    Science.gov (United States)

    Ishida, Hisashi

    2014-09-01

    Proteasome is involved in the degradation of proteins. Proteasome activators bind to the proteasome core particle (CP) and facilitate opening a gate of the CP, where Tyr8 and Asp9 in the N-termini tails of the CP form the ordered open gate. In a double mutant (Tyr8Gly/Asp9Gly), the N-termini tails are disordered and the stabilized open-gate conformation cannot be formed. To understand the gating mechanism of the CP for the translocation of the substrate, four different molecular dynamics simulations were carried out: ordered- and Tyr8Gly/Asp9Gly disordered-gate models of the CP complexed with an ATP-independent PA26 and ordered- and disordered-gate models of the CP complexed with an ATP-dependent PAN-like activator. The free-energies of the translocation of a polypeptide substrate moving through the gate were estimated. In the ordered-gate models, the substrate in the activator was more stable than that in the CP. The conformational entropy of the N-termini tails of the CP was larger when the substrate was in the activator than in the CP. In the disordered-gate models, the substrate in the activator was more destabilized than in the ordered-gate models. The mutated N-termini tails became randomized and their increased conformational entropy could no longer increase further even when the substrate was in the activator, meaning the randomized N-termini tails had lost the ability to stabilize the substrate in the activator. Thus, it was concluded that the dynamics of the N-termini tails entropically play a key role in the translocation of the substrate. © 2014 Wiley Periodicals, Inc.

  20. REPRODUCTIVE HEALTH IN RICKSHAW DRIVERS: Occupational Exposure to Environmental Stressor

    Directory of Open Access Journals (Sweden)

    Ghulam. Nabi

    2014-08-01

    Full Text Available Background: In urban environment, exposure to the emission of motor vehicles is common. In urban peoples it is a very difficult task to distinguish among peoples with different grades of momentous period exposure to such pollutants. Objective: The objective of this study was to determine the effects of diesel exhaust, gasoline emission, Particulate Matter (PM noise and heat on the reproductive health of rickshaw drivers. Methods: Adult married male individuals were recruited randomly in the study from Btkhella, Malakand agency, Khyber Pakhtunkhwa, Pakistan. Two groups were made, control (n=45 and rickshaw drivers (n=50. A special questionnaire was designed about occupational activities, socio-demographic and clinical characteristics. From both groups 5 mL of the blood was collected and was analyze for serum total testosterone and cortisol using Biocheck (USA and Antibodies-online GmbH (Germany kits. Results: In control group the Mean±SEM of total serum testosterone was 657.6±16.84 ng/dl and cortisol was 443.8±14.67 mU/L. In rickshaw drivers the Mean±SEM of total serum testosterone was 577.1±11.42 ng/dl and cortisol was 595.1±8.879mU/L. In rickshaw drivers there was a significant reduction in total serum testosterone (P0.0002 but a significant increase in serum cortisol level (P < 0.0001 at 95% confidence interval. Conclusions: Reproductive health problems like decreased libido, erectile dysfunction, absent morning and nocturnal erection, ejaculatory problems, primary infertility and secondary infertility were prevalent in rickshaw drivers but, no such problems were found in control group. Chronic exposure to pollutants such as diesel exhaust, gasoline emission, Particulate Matter (PM noise and heat negatively regulate Hypothalmo-Pituitary Gonadal axis (HPG leading  to reproductive problems.

  1. Drivers for Energy Efficiency in Indian Railway Workshops

    Directory of Open Access Journals (Sweden)

    Suresh D. Mane,

    2013-09-01

    Full Text Available - Two major railway coach repair workshops involved in periodical overhauling of broad gauge passenger coaches located in south India has been undertaken for studying the drivers for energy conservation(EC. The study covers a period of six calendar years from 2007 to 2012 and takes into account the various activities in terms of maintenance of coaches and production of components the energy input for both the workshops. Carriage Repair Workshop Hubli (UBLS Central Workshops Mysore (MYSS have introduced many an EC measures yielding good results. The extended study was then undertaken to analyse the drivers for energy efficiency in both of these workshops. The main stakeholders in both the workshops viz. the officers and senior section engineers (SSE’s were interviewed separately and their experience on the drivers for EC were sought. Totally seven drivers for EC were arrived at from the discussions with the stakeholders. To rank these seven drivers a questionnaire was devised to capture the data from both of these workshops and weighted average method adopted for ranking. The stakeholders were briefed of the questionnaire so as to make them accustomed to it. 82 respondents from UBLS and 41 respondents from MYSS filled up the forms in all respects which were used for analysis using weighted average method. Results show the similar first three ranking in both the workshops with total weighted average of greater than 0.5. The top ranked driver of both the workshops was dedication of the top management, engineers and staff with a weighted average score of 0.18 and 0.19 respectively from MYSS and UBLS respectively. The driver “awareness and adoption of latest technologies for EC” is a close second with a weighted average of 0.16 and 0.17 respectively from MYSS and UBLS respectively. Capacity utilization is ranked third which again is common for both the workshops. It was found that due to better awareness about environment at MYSS, it was ranked

  2. Pedestrian-driver communication and decision strategies at marked crossings.

    Science.gov (United States)

    Sucha, Matus; Dostal, Daniel; Risser, Ralf

    2017-03-02

    The aim of this work is to describe pedestrian-driver encounters, communication, and decision strategies at marked but unsignalised crossings in urban areas in the Czech Republic and the ways in which the parties involved experience and handle these encounters. A mixed-methods design was used, consisting of focus groups with pedestrians and drivers regarding their subjective views of the situations, on-site observations, camera recordings, speed measurements, the measurement of car and pedestrian densities, and brief on-site interviews with pedestrians. In close correspondence with the literature, our study revealed that the most relevant predictors of pedestrians' and drivers' behaviour at crossings were the densities of car traffic and pedestrian flows and car speed. The factors which influenced pedestrians' wait/go behaviour were: car speed, the distance of the car from the crossing, traffic density, whether there were cars approaching from both directions, various signs given by the driver (eye contact, waving a hand, flashing their lights), and the presence of other pedestrians. The factors influencing drivers' yield/go behaviour were: speed, traffic density, the number of pedestrians waiting to cross, and pedestrians being distracted. A great proportion of drivers (36%) failed to yield to pedestrians at marked crossings. The probability of conflict situations increased with cars travelling at a higher speed, higher traffic density, and pedestrians being distracted by a different activity while crossing. The findings of this study can add to the existing literature by helping to provide an understanding of the perception of encounter situations by the parties involved and the motives lying behind certain aspects of behaviour associated with these encounters. This seems necessary in order to develop suggestions for improvements. For instance, the infrastructure near pedestrian crossings should be designed in such a way as to take proper account of pedestrians

  3. Driving Cessation Anno 2010 Which Older Drivers Give Up Their License and Why? Evidence From Denmark

    DEFF Research Database (Denmark)

    Siren, Anu Kristiina; Haustein, Sonja

    2016-01-01

    This study focuses on the decision to either stop or continue driving among a cohort of Danish seniors whose driving licenses expire, for the first time, at the age of 70. Based on 1,537 standardized telephone interviews with licensed drivers, we compared persons who intended to renew...... or not to renew their licenses. The results partly recapture the findings of earlier studies. However, in contrast to former cohorts, a much higher percentage of older drivers intended to keep their licenses. The strongest factors predicting the intention to renew were active car use, feeling safe as a driver...

  4. Protected gates for topological quantum field theories

    Energy Technology Data Exchange (ETDEWEB)

    Beverland, Michael E.; Pastawski, Fernando; Preskill, John [Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125 (United States); Buerschaper, Oliver [Dahlem Center for Complex Quantum Systems, Freie Universität Berlin, 14195 Berlin (Germany); Koenig, Robert [Institute for Advanced Study and Zentrum Mathematik, Technische Universität München, 85748 Garching (Germany); Sijher, Sumit [Institute for Quantum Computing and Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada)

    2016-02-15

    We study restrictions on locality-preserving unitary logical gates for topological quantum codes in two spatial dimensions. A locality-preserving operation is one which maps local operators to local operators — for example, a constant-depth quantum circuit of geometrically local gates, or evolution for a constant time governed by a geometrically local bounded-strength Hamiltonian. Locality-preserving logical gates of topological codes are intrinsically fault tolerant because spatially localized errors remain localized, and hence sufficiently dilute errors remain correctable. By invoking general properties of two-dimensional topological field theories, we find that the locality-preserving logical gates are severely limited for codes which admit non-abelian anyons, in particular, there are no locality-preserving logical gates on the torus or the sphere with M punctures if the braiding of anyons is computationally universal. Furthermore, for Ising anyons on the M-punctured sphere, locality-preserving gates must be elements of the logical Pauli group. We derive these results by relating logical gates of a topological code to automorphisms of the Verlinde algebra of the corresponding anyon model, and by requiring the logical gates to be compatible with basis changes in the logical Hilbert space arising from local F-moves and the mapping class group.

  5. TRADITIONAL WOODEN GATES IN THE SZEKLER LAND

    Directory of Open Access Journals (Sweden)

    GhiorghiŃă Nicolaie COMSA

    2013-09-01

    Full Text Available This paper presents specific aspects oftraditional wooden gates built in the rural area of thecounty of Harghita in Romania. One can see the loveand appreciation given to woodworking and outdoorelements of household adornment, beautiful insidetransmitted outside. Constructive elements andornaments are given specific geographical area.These gates belong to our national cultural heritage.

  6. How voltage-gated calcium channels gate forms of homeostatic synaptic plasticity

    Directory of Open Access Journals (Sweden)

    C. Andrew eFrank

    2014-02-01

    Full Text Available Throughout life, animals face a variety of challenges such as developmental growth, the presence of toxins, or changes in temperature. Neuronal circuits and synapses respond to challenges by executing an array of neuroplasticity paradigms. Some paradigms allow neurons to up- or downregulate activity outputs, while countervailing ones ensure that outputs remain within appropriate physiological ranges. A growing body of evidence suggests that homeostatic synaptic plasticity (HSP is critical in the latter case. Voltage-gated calcium channels gate forms of HSP. Presynaptically, the aggregate data show that when synapse activity is weakened, homeostatic signaling systems can act to correct impairments, in part by increasing calcium influx through presynaptic CaV2-type channels. Increased calcium influx is often accompanied by parallel increases in the size of active zones and the size of the readily releasable pool of presynaptic vesicles. These changes coincide with homeostatic enhancements of neurotransmitter release. Postsynaptically, there is a great deal of evidence that reduced network activity and loss of calcium influx through CaV1-type calcium channels also results in adaptive homeostatic signaling. Some adaptations drive presynaptic enhancements of vesicle pool size and turnover rate via retrograde signaling, as well as de novo insertion of postsynaptic neurotransmitter receptors. Enhanced calcium influx through CaV1 after network activation or single cell stimulation can elicit the opposite response – homeostatic depression via removal of excitatory receptors.There exist intriguing links between HSP and calcium channelopathies – such as forms of epilepsy, migraine, ataxia, and myasthenia. The episodic nature of some of these disorders suggests alternating periods of stable and unstable function. Uncovering information about how calcium channels are regulated in the context of HSP could be relevant toward understanding these and other

  7. Assessing the relationship between the Driver Behavior Questionnaire and the Driver Skill Inventory: Revealing sub-groups of drivers

    DEFF Research Database (Denmark)

    Martinussen, Laila Marianne; Møller, Mette; Prato, Carlo Giacomo

    2014-01-01

    The Driver Behavior Questionnaire and the Driver Skill Inventory are two of the most frequently used measures of self-reported driving style and driving skill. The motivation behind the present study was to identify sub-groups of drivers that potentially act dangerously in traffic (as measured by...... driving behaviors, and vice versa. The present findings highlight the need to look into driver’s attitudes towards safety, and to devise differential interventions targeting specific problematic groups of the population in the attempt to improve road safety nationwide....

  8. Dual-Gate p-GaN Gate High Electron Mobility Transistors for Steep Subthreshold Slope.

    Science.gov (United States)

    Bae, Jong-Ho; Lee, Jong-Ho

    2016-05-01

    A steep subthreshold slope characteristic is achieved through p-GaN gate HEMT with dual-gate structure. Obtained subthreshold slope is less than 120 μV/dec. Based on the measured and simulated data obtained from single-gate device, breakdown of parasitic floating-base bipolar transistor and floating gate charged with holes are responsible to increase abruptly in drain current. In the dual-gate device, on-current degrades with high temperature but subthreshold slope is not changed. To observe the switching speed of dual-gate device and transient response of drain current are measured. According to the transient responses of drain current, switching speed of the dual-gate device is about 10(-5) sec.

  9. Logic gates based on ion transistors.

    Science.gov (United States)

    Tybrandt, Klas; Forchheimer, Robert; Berggren, Magnus

    2012-05-29

    Precise control over processing, transport and delivery of ionic and molecular signals is of great importance in numerous fields of life sciences. Integrated circuits based on ion transistors would be one approach to route and dispense complex chemical signal patterns to achieve such control. To date several types of ion transistors have been reported; however, only individual devices have so far been presented and most of them are not functional at physiological salt concentrations. Here we report integrated chemical logic gates based on ion bipolar junction transistors. Inverters and NAND gates of both npn type and complementary type are demonstrated. We find that complementary ion gates have higher gain and lower power consumption, as compared with the single transistor-type gates, which imitates the advantages of complementary logics found in conventional electronics. Ion inverters and NAND gates lay the groundwork for further development of solid-state chemical delivery circuits.

  10. Airport Gate Assignment: New Model and Implementation

    CERN Document Server

    Li, Chendong

    2008-01-01

    Airport gate assignment is of great importance in airport operations. In this paper, we study the Airport Gate Assignment Problem (AGAP), propose a new model and implement the model with Optimization Programming language (OPL). With the objective to minimize the number of conflicts of any two adjacent aircrafts assigned to the same gate, we build a mathematical model with logical constraints and the binary constraints, which can provide an efficient evaluation criterion for the Airlines to estimate the current gate assignment. To illustrate the feasibility of the model we construct experiments with the data obtained from Continental Airlines, Houston Gorge Bush Intercontinental Airport IAH, which indicate that our model is both energetic and effective. Moreover, we interpret experimental results, which further demonstrate that our proposed model can provide a powerful tool for airline companies to estimate the efficiency of their current work of gate assignment.

  11. Gating of Permanent Molds for ALuminum Casting

    Energy Technology Data Exchange (ETDEWEB)

    David Schwam; John F. Wallace; Tom Engle; Qingming Chang

    2004-03-30

    This report summarizes a two-year project, DE-FC07-01ID13983 that concerns the gating of aluminum castings in permanent molds. The main goal of the project is to improve the quality of aluminum castings produced in permanent molds. The approach taken was determine how the vertical type gating systems used for permanent mold castings can be designed to fill the mold cavity with a minimum of damage to the quality of the resulting casting. It is evident that somewhat different systems are preferred for different shapes and sizes of aluminum castings. The main problems caused by improper gating are entrained aluminum oxide films and entrapped gas. The project highlights the characteristic features of gating systems used in permanent mold aluminum foundries and recommends gating procedures designed to avoid common defects. The study also provides direct evidence on the filling pattern and heat flow behavior in permanent mold castings.

  12. Monte Carlo analysis of a low power domino gate under parameter fluctuation

    Institute of Scientific and Technical Information of China (English)

    Wang Jinhui; Wu Wuchen; Gong Na; Hou Ligang; Peng Xiaohong; Gao Daming

    2009-01-01

    Using the multiple-parameter Monte Carlo method, the effectiveness of the dual threshold voltage technique (DTV) in low power domino logic design is analyzed. Simulation results indicate that under significant temperature and process fluctuations, DTV is still highly effective in reducing the total leakage and active power consumption for domino gates with speed loss. Also, regarding power and delay characteristics, different structure domino gates with DTV have different robustness against temperature and process fluctuation.

  13. Monte Carlo analysis of a low power domino gate under parameter fluctuation

    Energy Technology Data Exchange (ETDEWEB)

    Wang Jinhui; Wu Wuchen; Hou Ligang; Peng Xiaohong; Gao Daming [VLSI and System Laboratory, Beijing University of Technology, Beijing 100124 (China); Gong Na, E-mail: wangjinhui888@emails.bjut.edu.c [Department of Computer Science and Engineering, State University of New York at Buffalo, Buffalo 14260, NY (United States)

    2009-12-15

    Using the multiple-parameter Monte Carlo method, the effectiveness of the dual threshold voltage technique (DTV) in low power domino logic design is analyzed. Simulation results indicate that under significant temperature and process fluctuations, DTV is still highly effective in reducing the total leakage and active power consumption for domino gates with speed loss. Also, regarding power and delay characteristics, different structure domino gates with DTV have different robustness against temperature and process fluctuation. (semiconductor integrated circuits)

  14. Square pulse linear transformer driver

    Directory of Open Access Journals (Sweden)

    A. A. Kim

    2012-04-01

    Full Text Available The linear transformer driver (LTD technological approach can result in relatively compact devices that can deliver fast, high current, and high-voltage pulses straight out of the LTD cavity without any complicated pulse forming and pulse compression network. Through multistage inductively insulated voltage adders, the output pulse, increased in voltage amplitude, can be applied directly to the load. The usual LTD architecture [A. A. Kim, M. G. Mazarakis, V. A. Sinebryukhov, B. M. Kovalchuk, V. A. Vizir, S. N Volkov, F. Bayol, A. N. Bastrikov, V. G. Durakov, S. V. Frolov, V. M. Alexeenko, D. H. McDaniel, W. E. Fowler, K. LeCheen, C. Olson, W. A. Stygar, K. W. Struve, J. Porter, and R. M. Gilgenbach, Phys. Rev. ST Accel. Beams 12, 050402 (2009PRABFM1098-440210.1103/PhysRevSTAB.12.050402; M. G. Mazarakis, W. E. Fowler, A. A. Kim, V. A. Sinebryukhov, S. T. Rogowski, R. A. Sharpe, D. H. McDaniel, C. L. Olson, J. L. Porter, K. W. Struve, W. A. Stygar, and J. R. Woodworth, Phys. Rev. ST Accel. Beams 12, 050401 (2009PRABFM1098-440210.1103/PhysRevSTAB.12.050401] provides sine shaped output pulses that may not be well suited for some applications like z-pinch drivers, flash radiography, high power microwaves, etc. A more suitable power pulse would have a flat or trapezoidal (rising or falling top. In this paper, we present the design and first test results of an LTD cavity that generates such a type of output pulse by including within its circular array a number of third harmonic bricks in addition to the main bricks. A voltage adder made out of a square pulse cavity linear array will produce the same shape output pulses provided that the timing of each cavity is synchronized with the propagation of the electromagnetic pulse.

  15. Risk drivers pose to themselves and other drivers by violating traffic rules.

    Science.gov (United States)

    Penmetsa, Praveena; Pulugurtha, Srinivas S

    2017-01-02

    Violation of traffic rules is a major contributing factor in both crashes and fatalities in the United States. This study aims at quantifying risk that drivers pose to themselves and other drivers by violating traffic rules. Crash data from 2010 to 2013 were gathered for the state of North Carolina. Descriptive analysis was carried out to identify frequent traffic violations and who were committing the traffic violations that resulted in crashes. A multinomial logit model was then developed to examine the relation between different traffic violations and driver injury severity. Additionally, odds ratios were estimated to identify the likelihood (probability) of severe or moderate injury to the driver and other drivers due to a driver violating a traffic rule that led to a crash. Exceeding the speed limit is more likely to result in severe injury compared to disregarding traffic signals. However, going the wrong way is more likely to result in severe injury to other drivers when compared to any other traffic violation. Driving under the influence of alcohol is 2 times more likely to result in severe injury than driving under the influence of drugs. These 2 traffic violations by a driver are almost equally likely to result in severe injury to other drivers. Drivers often perceive that violating traffic rules will not result in a crash or severe injury. However, the results from this study show that a majority of the traffic violations lead to severe injury to the violator as well as to other drivers. The findings from this study serve as documented evidence to educate drivers about the risk they pose to themselves and to other drivers by violating traffic rules and encourage the adaptation of safe driving behavior in order to contribute toward reaching the "zero traffic deaths" vision. They also help make policy changes pertaining to penalty points and fines for violating a traffic rule.

  16. Approaches of truck drivers and non-truck drivers toward reckless on-road behavior.

    Science.gov (United States)

    Rosenbloom, Tova; Eldror, Ehud; Shahar, Amit

    2009-07-01

    The purpose of the study was to compare the reported approaches of truck drivers to those of non-truck drivers toward reckless on-road behaviors. One hundred and sixty-seven adult males, including 70 non-truck drivers, completed the questionnaires voluntarily. The truck drivers were employees of a concrete manufacturing company working at various company plants throughout Israel. Seventy were professional mixer truckers and 27 were tip-truckers. The participants completed the Reckless Driving Self-Report Scale based on Taubman Ben-Ari et al. [Taubman Ben-Ari, O., Florian, V., Mikulincer, M., 1999. The impact of mortality salience on reckless driving: a test of terror management mechanisms. Journal of Personality and Social Psychology 76, 35-45], adapted for truck drivers for this study. It was expected that non-professional, as compared to professional (truck) drivers, would be more permissive regarding reckless driving, since driving risks are less prominent in their daily driving experience. An ANOVA performed on mean reckless-driving scores yielded significant results. The post hoc Schéffe test indicated significantly higher reckless-driving scores for automobile drivers as compared to both mixer-truck driver scores and tip-truck driver scores. In addition, the reckless-driving scores for mixer-truck drivers were significantly higher than the tip-truck driver scores. We discuss various explanations for the findings and consider possible implications for training strategies in organizations as well as for media campaigns focused on mutual safe road use of truck drivers and private vehicle drivers.

  17. Materials Fundamentals of Gate Dielectrics

    CERN Document Server

    Demkov, Alexander A

    2006-01-01

    This book presents materials fundamentals of novel gate dielectrics that are being introduced into semiconductor manufacturing to ensure the continuous scalling of the CMOS devices. This is a very fast evolving field of research so we choose to focus on the basic understanding of the structure, thermodunamics, and electronic properties of these materials that determine their performance in device applications. Most of these materials are transition metal oxides. Ironically, the d-orbitals responsible for the high dielectric constant cause sever integration difficulties thus intrinsically limiting high-k dielectrics. Though new in the electronics industry many of these materials are wel known in the field of ceramics, and we describe this unique connection. The complexity of the structure-property relations in TM oxides makes the use of the state of the art first-principles calculations necessary. Several chapters give a detailed description of the modern theory of polarization, and heterojunction band discont...

  18. Crystal Structure of the Mammalian GIRK2 KplusChannel and Gating Regulation by G Proteins PIP2 and Sodium

    Energy Technology Data Exchange (ETDEWEB)

    M Whorton; R MacKinnon

    2011-12-31

    G protein-gated K{sup +} channels (Kir3.1--Kir3.4) control electrical excitability in many different cells. Among their functions relevant to human physiology and disease, they regulate the heart rate and govern a wide range of neuronal activities. Here, we present the first crystal structures of a G protein-gated K{sup +} channel. By comparing the wild-type structure to that of a constitutively active mutant, we identify a global conformational change through which G proteins could open a G loop gate in the cytoplasmic domain. The structures of both channels in the absence and presence of PIP{sub 2} suggest that G proteins open only the G loop gate in the absence of PIP{sub 2}, but in the presence of PIP{sub 2} the G loop gate and a second inner helix gate become coupled, so that both gates open. We also identify a strategically located Na{sup +} ion-binding site, which would allow intracellular Na{sup +} to modulate GIRK channel activity. These data provide a structural basis for understanding multiligand regulation of GIRK channel gating.

  19. Low back pain among taxi drivers: a cross-sectional study.

    Science.gov (United States)

    Wang, M; Yu, J; Liu, N; Liu, Z; Wei, X; Yan, F; Yu, S

    2017-06-01

    Low back pain (LBP) is a common occupational problem for drivers all over the world. However, few epidemiological studies have investigated LBP among taxi drivers. To investigate the prevalence of LBP and associated work-related factors among Chinese taxi drivers. A cross-sectional survey was administered to all participants. Using cluster sampling, questionnaires were collected from taxi drivers of three major taxi companies in Jinan, China. Univariate and multivariate logistic regressions were used to estimate the odd ratios (ORs) and 95% confidence intervals (CIs) among participants. A total of 800 taxi drivers were invited to take part, with a participation rate of 90%. The 1-year period prevalence of LBP was 54%. Multivariate logistic regression analysis revealed that longer daily driving duration (OR 3.3, 95% CI 1.9-5.9), night shifts (OR 1.9, 95% CI 1.2-3.1) and increasing work years as a taxi driver (OR 1.7, 95% CI 1.2-2.5) were associated with increased risk of reporting LBP; while increased rest days per month (OR 0.8, 95% CI 0.7-0.9), longer sleep duration (OR 0.7, 95% CI 0.5-0.9) and more physical activity (OR 0.5, 95% CI 0.3-0.8) were significantly associated with decreased risk of reporting LBP. The prevalence of LBP among professional taxi drivers in China was associated with a number of occupational features.

  20. Prediction of Driver's Intention of Lane Change by Augmenting Sensor Information Using Machine Learning Techniques.

    Science.gov (United States)

    Kim, Il-Hwan; Bong, Jae-Hwan; Park, Jooyoung; Park, Shinsuk

    2017-06-10

    Driver assistance systems have become a major safety feature of modern passenger vehicles. The advanced driver assistance system (ADAS) is one of the active safety systems to improve the vehicle control performance and, thus, the safety of the driver and the passengers. To use the ADAS for lane change control, rapid and correct detection of the driver's intention is essential. This study proposes a novel preprocessing algorithm for the ADAS to improve the accuracy in classifying the driver's intention for lane change by augmenting basic measurements from conventional on-board sensors. The information on the vehicle states and the road surface condition is augmented by using an artificial neural network (ANN) models, and the augmented information is fed to a support vector machine (SVM) to detect the driver's intention with high accuracy. The feasibility of the developed algorithm was tested through driving simulator experiments. The results show that the classification accuracy for the driver's intention can be improved by providing an SVM model with sufficient driving information augmented by using ANN models of vehicle dynamics.

  1. Event-Based Modeling of Driver Yielding Behavior at Unsignalized Crosswalks.

    Science.gov (United States)

    Schroeder, Bastian J; Rouphail, Nagui M

    2011-07-01

    This research explores factors associated with driver yielding behavior at unsignalized pedestrian crossings and develops predictive models for yielding using logistic regression. It considers the effect of variables describing driver attributes, pedestrian characteristics and concurrent conditions at the crosswalk on the yield response. Special consideration is given to 'vehicle dynamics constraints' that form a threshold for the potential to yield. Similarities are identified to driver reaction in response to the 'amber' indication at a signalized intersection. The logit models were developed from data collected at two unsignalized mid-block crosswalks in North Carolina. The data include 'before' and 'after' observations of two pedestrian safety treatments, an in-street pedestrian crossing sign and pedestrian-actuated in-roadway warning lights.The analysis suggests that drivers are more likely to yield to assertive pedestrians who walk briskly in their approach to the crosswalk. In turn, the yield probability is reduced with higher speeds, deceleration rates and if vehicles are traveling in platoons. The treatment effects proved to be significant and increased the propensity of drivers to yield, but their effectiveness may be dependent on whether the pedestrian activates the treatment.The results of this research provide new insights on the complex interaction of pedestrians and vehicles at unsignalized intersections and have implications for future work towards predictive models for driver yielding behavior. The developed logit models can provide the basis for representing driver yielding behavior in a microsimulation modeling environment.

  2. Drivers' communicative interactions: on-road observations and modelling for integration in future automation systems.

    Science.gov (United States)

    Portouli, Evangelia; Nathanael, Dimitris; Marmaras, Nicolas

    2014-01-01

    Social interactions with other road users are an essential component of the driving activity and may prove critical in view of future automation systems; still up to now they have received only limited attention in the scientific literature. In this paper, it is argued that drivers base their anticipations about the traffic scene to a large extent on observations of social behaviour of other 'animate human-vehicles'. It is further argued that in cases of uncertainty, drivers seek to establish a mutual situational awareness through deliberate communicative interactions. A linguistic model is proposed for modelling these communicative interactions. Empirical evidence from on-road observations and analysis of concurrent running commentary by 25 experienced drivers support the proposed model. It is suggested that the integration of a social interactions layer based on illocutionary acts in future driving support and automation systems will improve their performance towards matching human driver's expectations. Practitioner Summary: Interactions between drivers on the road may play a significant role in traffic coordination. On-road observations and running commentaries are presented as empirical evidence to support a model of such interactions; incorporation of drivers' interactions in future driving support and automation systems may improve their performance towards matching driver's expectations.

  3. Tarantula: Killing driver bugs before they hatch

    DEFF Research Database (Denmark)

    Lawall, Julia Laetitia; Muller, Gilles; Urunuela, Richard

    2005-01-01

    The Linux operating system is undergoing continual evolution. Evolution in the kernel and generic driver modules often triggers the need for corresponding evolutions in specific device drivers. Such collateral evolutions are tedious, because of the large number of device drivers, and error......-prone, because of the complexity of the code modifications involved. We propose an automatic tool, Tarantula, to aid in this process. In this paper, we examine some recent evolutions in Linux and the collateral evolutions they trigger, and assess the corresponding requirements on Tarantula....

  4. CMOS Law-jitter Clock Driver Design

    OpenAIRE

    2012-01-01

    [ANGLÈS] Design of a low-jitter, low-phase noise clock driver in 40 nm CMOS technology. The work is in the field of analog integrated circuit (IC) design in nanometer CMOS technologies. [CASTELLÀ] Diseño de un circuito integrado "clock driver" de bajo jitter y bajo ruido de fase en tecnología CMOS 40 nm. El trabajo se contextualiza en el campo del diseño de circuitos integrados analógicos en tecnologías CMOS nanométricas. [CATALÀ] Disseny d'un circuit "clock driver" de baix jitter i bai...

  5. LC Oscillator Driver for Safety Critical Applications

    CERN Document Server

    Horsky, Pavel

    2011-01-01

    A CMOS harmonic signal LC oscillator driver for automotive applications working in a harsh environment with high safety critical requirements is described. The driver can be used with a wide range of external components parameters (LC resonance network of a sensor). Quality factor of the external LC network can vary two decades. Amplitude regulation of the driver is digitally controlled and the DAC is constructed as exponential with piece-wise-linear (PWL) approximation. Low current consumption for high quality resonance networks is achieved. Realized oscillator is robust, used in safety critical application and has low EMC emissions.

  6. Tarantula: Killing driver bugs before they hatch

    DEFF Research Database (Denmark)

    Lawall, Julia Laetitia; Muller, Gilles; Urunuela, Richard

    2005-01-01

    The Linux operating system is undergoing continual evolution. Evolution in the kernel and generic driver modules often triggers the need for corresponding evolutions in specific device drivers. Such collateral evolutions are tedious, because of the large number of device drivers, and error......-prone, because of the complexity of the code modifications involved. We propose an automatic tool, Tarantula, to aid in this process. In this paper, we examine some recent evolutions in Linux and the collateral evolutions they trigger, and assess the corresponding requirements on Tarantula....

  7. Optimizing the Universal Robots ROS driver

    DEFF Research Database (Denmark)

    Andersen, Thomas Timm

    In this report I will examine both the current and the possible performance of one of the most popular robotics platforms in research, the Universal Robot manipulator. I will solely focus on the ROS based approaches and show how the current driver can be improved. I will look at performance...... improvement both in terms of faster reaction as well as making it possible to control the robot using either ros_control or ordinary joint speed commands, which is required for many types of sensory based control like visual servoing. The developed driver is compared to the drivers already existing in the ROS...

  8. Driver style and driver skill – Clustering sub-groups of drivers differing in their potential danger in traffic

    DEFF Research Database (Denmark)

    Martinussen, Laila Marianne; Møller, Mette; Prato, Carlo Giacomo

    based on a combined use of the DBQ and the DSI. Moreover, the joint use of the two instruments was applied to identify sub-groups of drivers that differ in their potential danger in traffic (as measured by frequency of aberrant driving behaviors and level of driving skills), as well as to test whether...... the sub-groups of drivers differed in characteristics such as age, gender, annual mileage and accident involvement. 3908 drivers aged 18–84 participated in the survey. The results suggested that the drivers are consistent in their reporting of driving ability, as the self-reported driving skill level...... mirrored the self-reported frequency of aberrant driving behaviors. K-means cluster analysis revealed four distinct clusters that differed in the frequency of aberrant driving behavior and driving skills, as well as individual characteristics and driving related factors such as annual mileage, accident...

  9. Assessing the relationship between the Driver Behavior Questionnaire and the Driver Skill Inventory: Revealing sub-groups of drivers

    DEFF Research Database (Denmark)

    Martinussen, Laila Marianne; Møller, Mette; Prato, Carlo Giacomo

    2014-01-01

    The Driver Behavior Questionnaire and the Driver Skill Inventory are two of the most frequently used measures of self-reported driving style and driving skill. The motivation behind the present study was to identify sub-groups of drivers that potentially act dangerously in traffic (as measured...... by frequency of aberrant driving behaviors and level of driving skills), as well as to test whether the sub-groups differ in characteristics such as age, gender, annual mileage and accident involvement. Furthermore, the joint analysis of the two instruments was used to test drivers’ assessment of their own...... self-reported driving skills and whether the reported skill level was reflected in the reported aberrant driving behaviors. 3908 drivers aged 18–84 participated in the survey. K-means cluster analysis revealed four distinct sub-groups that differed in driving skills and frequency of aberrant driving...

  10. Food consumption trends and drivers.

    Science.gov (United States)

    Kearney, John

    2010-09-27

    A picture of food consumption (availability) trends and projections to 2050, both globally and for different regions of the world, along with the drivers largely responsible for these observed consumption trends are the subject of this review. Throughout the world, major shifts in dietary patterns are occurring, even in the consumption of basic staples towards more diversified diets. Accompanying these changes in food consumption at a global and regional level have been considerable health consequences. Populations in those countries undergoing rapid transition are experiencing nutritional transition. The diverse nature of this transition may be the result of differences in socio-demographic factors and other consumer characteristics. Among other factors including urbanization and food industry marketing, the policies of trade liberalization over the past two decades have implications for health by virtue of being a factor in facilitating the 'nutrition transition' that is associated with rising rates of obesity and chronic diseases such as cardiovascular disease and cancer. Future food policies must consider both agricultural and health sectors, thereby enabling the development of coherent and sustainable policies that will ultimately benefit agriculture, human health and the environment.

  11. State-dependent changes in auditory sensory gating in different cortical areas in rats.

    Directory of Open Access Journals (Sweden)

    Renli Qi

    Full Text Available Sensory gating is a process in which the brain's response to a repetitive stimulus is attenuated; it is thought to contribute to information processing by enabling organisms to filter extraneous sensory inputs from the environment. To date, sensory gating has typically been used to determine whether brain function is impaired, such as in individuals with schizophrenia or addiction. In healthy subjects, sensory gating is sensitive to a subject's behavioral state, such as acute stress and attention. The cortical response to sensory stimulation significantly decreases during sleep; however, information processing continues throughout sleep, and an auditory evoked potential (AEP can be elicited by sound. It is not known whether sensory gating changes during sleep. Sleep is a non-uniform process in the whole brain with regional differences in neural activities. Thus, another question arises concerning whether sensory gating changes are uniform in different brain areas from waking to sleep. To address these questions, we used the sound stimuli of a Conditioning-testing paradigm to examine sensory gating during waking, rapid eye movement (REM sleep and Non-REM (NREM sleep in different cortical areas in rats. We demonstrated the following: 1. Auditory sensory gating was affected by vigilant states in the frontal and parietal areas but not in the occipital areas. 2. Auditory sensory gating decreased in NREM sleep but not REM sleep from waking in the frontal and parietal areas. 3. The decreased sensory gating in the frontal and parietal areas during NREM sleep was the result of a significant increase in the test sound amplitude.

  12. CRAF R391W is a melanoma driver oncogene

    Science.gov (United States)

    Atefi, Mohammad; Titz, Bjoern; Tsoi, Jennifer; Avramis, Earl; Le, Allison; Ng, Charles; Lomova, Anastasia; Lassen, Amanda; Friedman, Michael; Chmielowski, Bartosz; Ribas, Antoni; Graeber, Thomas G.

    2016-01-01

    Approximately 75% of melanomas have known driver oncogenic mutations in BRAF, NRAS, GNA11 or GNAQ, while the mutations providing constitutive oncogenic signaling in the remaining melanomas are not known. We established a melanoma cell line from a tumor with none of the common driver mutations. This cell line demonstrated a signaling profile similar to BRAF-mutants, but lacked sensitivity to the BRAF inhibitor vemurafenib. RNA-seq mutation data implicated CRAF R391W as the alternative driver mutation of this melanoma. CRAF R391W was homozygous and over expressed. These melanoma cells were highly sensitive to CRAF, but not BRAF knockdown. In reconstitution experiments, CRAF R391W, but not CRAF WT, transformed NIH3T3 cells in soft-agar colony formation assays, increased kinase activity in vitro, induced MAP kinase signaling and conferred vemurafenib resistance. MAP kinase inducing activity was dependent on CRAF dimerization. Thus, CRAF is a bona fide alternative oncogene for BRAF/NRAS/GNAQ/GNA11 wild type melanomas. PMID:27273450

  13. Older adult drivers living in residential care facilities

    Science.gov (United States)

    Lum, Hillary D.; Ginde, Adit A.; Betz, Marian E.

    2015-01-01

    Residential care facilities (RCF) provide assistance to older adults who cannot live independently, but it is unclear whether these residents have retired from driving. Here, we characterize older adults living in RCFs who still drive from a national cross-sectional survey of residents (2010 National Survey of Residential Care Facilities), representing ~733,000 adults living in RCFs such as assisted living facilities and personal care homes. Key resident characteristics were health, function, mobility and community activity indicators, which could be associated with increased driving risk. Of 8,087 residents, 4.5% (95%CI=3.9-5.1) were current drivers. Many drivers were older than 80 years (74%, 95%CI=67-79), in very good health (31%, 95%CI=25-38) or good health (35%, 95%CI=29-42), and had a median of two medical conditions. Most were independent with activities of daily living, though some needed assistance with walking and used gait devices. Given these results, RCF staff and healthcare providers need a heightened awareness of factors associated with driving risk to promote safety of older drivers and provide resources for likely transition to other transportation. PMID:26366125

  14. Eye State and Head Position Technique for Driver Drowsiness Detection

    Directory of Open Access Journals (Sweden)

    Ayush Joshi

    2013-06-01

    Full Text Available Many Driver Drowsiness Detection systems have been developed using eye and face detection methods but in this paper we have advanced the previous systems by adding the concept of head position technique. Till now none of the systems developed, have used the head position of the driver to detect the drowsiness, every paper have focused only on the face and eye detection concept. The head position technique is a newly introduced feature which enhances the performance of the system to a great extent. The systems capture frame and detects the face and eyes using HAAR-like classifiers, if the face is detected and eyes are closed then head position is monitored for next few frames, if the face is aligning down gradually and continuously then the alarm is activated.

  15. DriverNet: uncovering the impact of somatic driver mutations on transcriptional networks in cancer.

    Science.gov (United States)

    Bashashati, Ali; Haffari, Gholamreza; Ding, Jiarui; Ha, Gavin; Lui, Kenneth; Rosner, Jamie; Huntsman, David G; Caldas, Carlos; Aparicio, Samuel A; Shah, Sohrab P

    2012-12-22

    Simultaneous interrogation of tumor genomes and transcriptomes is underway in unprecedented global efforts. Yet, despite the essential need to separate driver mutations modulating gene expression networks from transcriptionally inert passenger mutations, robust computational methods to ascertain the impact of individual mutations on transcriptional networks are underdeveloped. We introduce a novel computational framework, DriverNet, to identify likely driver mutations by virtue of their effect on mRNA expression networks. Application to four cancer datasets reveals the prevalence of rare candidate driver mutations associated with disrupted transcriptional networks and a simultaneous modulation of oncogenic and metabolic networks, induced by copy number co-modification of adjacent oncogenic and metabolic drivers. DriverNet is available on Bioconductor or at http://compbio.bccrc.ca/software/drivernet/.

  16. A quantum Fredkin gate (Conference Presentation)

    Science.gov (United States)

    Patel, Raj B.; Ho, Joseph; Ferreyrol, Franck; Ralph, Timothy C.; Pryde, Geoff J.

    2016-10-01

    One of the greatest challenges in modern science is the realisation of quantum computers which, as their scale increases, will allow enhanced performance of tasks across many areas of quantum information processing. Quantum logic gates play a vital role in realising these applications by carrying out the elementary operations on the qubits; a key aim is minimising the resources needed to build these gates into useful circuits. While the salient features of a quantum computer have been shown in proof-of-principle experiments, e.g., single- and two-qubit gates, difficulties in scaling quantum systems to encode and manipulate multiple qubits has hindered demonstrations of more complex operations. This is exemplified by the classical Fredkin (or controlled-SWAP) gate [1] for which, despite many theoretical proposals [2,3] relying on concatenating multiple two-qubit gates, a quantum analogue has yet to be realised. Here, by directly adding control to a two-qubit SWAP unitary [4], we use photonic qubit logic to report the first experimental demonstration of a quantum Fredkin gate [5]. Our scheme uses linear optics and improves on the overall probability of success by an order of magnitude over previous proposals [2,3]. This optical approach allows us to add control an arbitrary black-box unitary which is otherwise forbidden in the standard circuit model [6]. Additionally, the action of our gate exhibits quantum coherence allowing the generation of the highest fidelity three-photon GHZ states to date. The quantum Fredkin gate has many applications in quantum computing, quantum measurements [7] and cryptography [8,9]. Using our scheme, we apply the Fredkin gate to the task of direct measurements of the purity and state overlap of a quantum system [7] without recourse to quantum state tomography.

  17. Driver ASICs for Advanced Deformable Mirrors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The program leverages on our extensive expertise in developing high-performance driver ASICs for deformable mirror systems and seeks to expand the capacities of the...

  18. Physics at a new Fermilab proton driver

    Energy Technology Data Exchange (ETDEWEB)

    Geer, Steve; /Fermilab

    2006-04-01

    In 2004, motivated by the recent exciting developments in neutrino physics, the Fermilab Long Range Planning Committee identified a new high intensity Proton Driver as an attractive option for the future. At the end of 2004 the APS ''Study on the Physics of Neutrinos'' concluded that the future US neutrino program should have, as one of its components, ''A proton driver in the megawatt class or above and neutrino superbeam with an appropriate very large detector capable of observing Cp violation and measuring the neutrino mass-squared differences and mixing parameters with high precision''. The presently proposed Fermilab Proton Driver is designed to accomplish these goals, and is based on, and would help develop, Linear Collider technology. In this paper the Proton Driver parameters are summarized, and the potential physics program is described.

  19. The importance of sight for drivers

    Directory of Open Access Journals (Sweden)

    Alicja Pas-Wyroślak

    2013-06-01

    Full Text Available Sight is the basic sense for drivers. Condition of the eye determines correct, comfortable and safe performance of the work as drivers. This article presents various factors influencing the sight condition. There are two groups of factors, external (environment, the kind and time of work, stress caused by work and internal (systemic and local disorders. All these factors can reduce significantly visual functions, such as visual acuity, field of vision, color vision, strereoscopic vision, twilight vision and glare sensitivity. There are also presented actual requirements for drivers and causes of the car accidents in various age groups. Impairments in vision functions can be dangerous for both the driver and other road users. Med Pr 2013;64(3:419–425

  20. Driver circuit for solid state light sources

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, Fred; Denvir, Kerry; Allen, Steven

    2016-02-16

    A driver circuit for a light source including one or more solid state light sources, a luminaire including the same, and a method of so driving the solid state light sources are provided. The driver circuit includes a rectifier circuit that receives an alternating current (AC) input voltage and provides a rectified AC voltage. The driver circuit also includes a switching converter circuit coupled to the light source. The switching converter circuit provides a direct current (DC) output to the light source in response to the rectified AC voltage. The driver circuit also includes a mixing circuit, coupled to the light source, to switch current through at least one solid state light source of the light source in response to each of a plurality of consecutive half-waves of the rectified AC voltage.