Science.gov

Sample records for reactive power regulation

  1. Index-based reactive power compensation scheme for voltage regulation

    NASA Astrophysics Data System (ADS)

    Dike, Damian Obioma

    2008-10-01

    Increasing demand for electrical power arising from deregulation and the restrictions posed to the construction of new transmission lines by environment, socioeconomic, and political issues had led to higher grid loading. Consequently, voltage instability has become a major concern, and reactive power support is vital to enhance transmission grid performance. Improved reactive power support to distressed grid is possible through the application of relatively unfamiliar emerging technologies of "Flexible AC Transmission Systems (FACTS)" devices and "Distributed Energy Resources (DERS)." In addition to these infrastructure issues, a lack of situational awareness by system operators can cause major power outages as evidenced by the August 14, 2003 widespread North American blackout. This and many other recent major outages have highlighted the inadequacies of existing power system indexes. In this work, a novel "Index-based reactive compensation scheme" appropriate for both on-line and off-line computation of grid status has been developed. A new voltage stability index (Ls-index) suitable for long transmission lines was developed, simulated, and compared to the existing two-machine modeled L-index. This showed the effect of long distance power wheeling amongst regional transmission organizations. The dissertation further provided models for index modulated voltage source converters (VSC) and index-based load flow analysis of both FACTS and microgrid interconnected power systems using the Newton-Raphson's load flow model incorporated with multi-FACTS devices. The developed package has been made user-friendly through the embodiment of interactive graphical user interface and implemented on the IEEE 14, 30, and 300 bus systems. The results showed reactive compensation has system wide-effect, provided readily accessible system status indicators, ensured seamless DERs interconnection through new islanding modes and enhanced VSC utilization. These outcomes may contribute

  2. Common station system for voltage and reactive power regulation at the Mosenergo TETs-27 heating and electric power plant

    SciTech Connect

    Krasnova, M. E.

    2009-05-15

    The system for common station regulation of the voltage and reactive power at the Mosenergo TETs-27 heating and electric power plant is described briefly. Features of the algorithms for this system, which uses programs and instrumentation from the automatic control system for the electrical equipment in the 450 MW power generation unit No. 3, are examined.

  3. A Tariff for Reactive Power

    SciTech Connect

    Kueck, John D; Kirby, Brendan J; Li, Fangxing; Tufon, Christopher; Isemonger, Alan

    2008-07-01

    Two kinds of power are required to operate an electric power system: real power, measured in watts, and reactive power, measured in volt-amperes reactive or VARs. Reactive power supply is one of a class of power system reliability services collectively known as ancillary services, and is essential for the reliable operation of the bulk power system. Reactive power flows when current leads or lags behind voltage. Typically, the current in a distribution system lags behind voltage because of inductive loads such as motors. Reactive power flow wastes energy and capacity and causes voltage droop. To correct lagging power flow, leading reactive power (current leading voltage) is supplied to bring the current into phase with voltage. When the current is in phase with voltage, there is a reduction in system losses, an increase in system capacity, and a rise in voltage. Reactive power can be supplied from either static or dynamic VAR sources. Static sources are typically transmission and distribution equipment, such as capacitors at substations, and their cost has historically been included in the revenue requirement of the transmission operator (TO), and recovered through cost-of-service rates. By contrast, dynamic sources are typically generators capable of producing variable levels of reactive power by automatically controlling the generator to regulate voltage. Transmission system devices such as synchronous condensers can also provide dynamic reactive power. A class of solid state devices (called flexible AC transmission system devices or FACTs) can provide dynamic reactive power. One specific device has the unfortunate name of static VAR compensator (SVC), where 'static' refers to the solid state nature of the device (it does not include rotating equipment) and not to the production of static reactive power. Dynamic sources at the distribution level, while more costly would be very useful in helping to regulate local voltage. Local voltage regulation would reduce

  4. Reactive Power Compensator.

    DOEpatents

    El-Sharkawi, M.A.; Venkata, S.S.; Chen, M.; Andexler, G.; Huang, T.

    1992-07-28

    A system and method for determining and providing reactive power compensation for an inductive load. A reactive power compensator (50,50') monitors the voltage and current flowing through each of three distribution lines (52a, 52b, 52c), which are supplying three-phase power to one or more inductive loads. Using signals indicative of the current on each of these lines when the voltage waveform on the line crosses zero, the reactive power compensator determines a reactive power compensator capacitance that must be connected to the lines to maintain a desired VAR level, power factor, or line voltage. Alternatively, an operator can manually select a specific capacitance for connection to each line, or the capacitance can be selected based on a time schedule. The reactive power compensator produces control signals, which are coupled through optical fibers (102/106) to a switch driver (110, 110') to select specific compensation capacitors (112) for connections to each line. The switch driver develops triggering signals that are supplied to a plurality of series-connected solid state switches (350), which control charge current in one direction in respect to ground for each compensation capacitor. During each cycle, current flows from ground to charge the capacitors as the voltage on the line begins to go negative from its positive peak value. The triggering signals are applied to gate the solid state switches into a conducting state when the potential on the lines and on the capacitors reaches a negative peak value, thereby minimizing both the potential difference and across the charge current through the switches when they begin to conduct. Any harmonic distortion on the potential and current carried by the lines is filtered out from the current and potential signals used by the reactive power compensator so that it does not affect the determination of the required reactive compensation. 26 figs.

  5. Reactive power compensator

    DOEpatents

    El-Sharkawi, Mohamed A.; Venkata, Subrahmanyam S.; Chen, Mingliang; Andexler, George; Huang, Tony

    1992-01-01

    A system and method for determining and providing reactive power compensation for an inductive load. A reactive power compensator (50,50') monitors the voltage and current flowing through each of three distribution lines (52a, 52b, 52c), which are supplying three-phase power to one or more inductive loads. Using signals indicative of the current on each of these lines when the voltage waveform on the line crosses zero, the reactive power compensator determines a reactive power compensator capacitance that must be connected to the lines to maintain a desired VAR level, power factor, or line voltage. Alternatively, an operator can manually select a specific capacitance for connection to each line, or the capacitance can be selected based on a time schedule. The reactive power compensator produces control signals, which are coupled through optical fibers (102/106) to a switch driver (110, 110') to select specific compensation capacitors (112) for connections to each line. The switch driver develops triggering signals that are supplied to a plurality of series-connected solid state switches (350), which control charge current in one direction in respect to ground for each compensation capacitor. During each cycle, current flows from ground to charge the capacitors as the voltage on the line begins to go negative from its positive peak value. The triggering signals are applied to gate the solid state switches into a conducting state when the potential on the lines and on the capacitors reaches a negative peak value, thereby minimizing both the potential difference and across the charge current through the switches when they begin to conduct. Any harmonic distortion on the potential and current carried by the lines is filtered out from the current and potential signals used by the reactive power compensator so that it does not affect the determination of the required reactive compensation.

  6. Process stabilization by peak current regulation in reactive high-power impulse magnetron sputtering of hafnium nitride

    NASA Astrophysics Data System (ADS)

    Shimizu, T.; Villamayor, M.; Lundin, D.; Helmersson, U.

    2016-02-01

    A simple and cost effective approach to stabilize the sputtering process in the transition zone during reactive high-power impulse magnetron sputtering (HiPIMS) is proposed. The method is based on real-time monitoring and control of the discharge current waveforms. To stabilize the process conditions at a given set point, a feedback control system was implemented that automatically regulates the pulse frequency, and thereby the average sputtering power, to maintain a constant maximum discharge current. In the present study, the variation of the pulse current waveforms over a wide range of reactive gas flows and pulse frequencies during a reactive HiPIMS process of Hf-N in an Ar-N2 atmosphere illustrates that the discharge current waveform is a an excellent indicator of the process conditions. Activating the reactive HiPIMS peak current regulation, stable process conditions were maintained when varying the N2 flow from 2.1 to 3.5 sccm by an automatic adjustment of the pulse frequency from 600 Hz to 1150 Hz and consequently an increase of the average power from 110 to 270 W. Hf-N films deposited using peak current regulation exhibited a stable stoichiometry, a nearly constant power-normalized deposition rate, and a polycrystalline cubic phase Hf-N with (1 1 1)-preferred orientation over the entire reactive gas flow range investigated. The physical reasons for the change in the current pulse waveform for different process conditions are discussed in some detail.

  7. Reactive power compensating system

    DOEpatents

    Williams, Timothy J.; El-Sharkawi, Mohamed A.; Venkata, Subrahmanyam S.

    1987-01-01

    The reactive power of an induction machine is compensated by providing fixed capacitors on each phase line for the minimum compensation required, sensing the current on one line at the time its voltage crosses zero to determine the actual compensation required for each phase, and selecting switched capacitors on each line to provide the balance of the compensation required.

  8. Reactive Power Compensating System.

    DOEpatents

    Williams, Timothy J.; El-Sharkawi, Mohamed A.; Venkata, Subrahmanyam S.

    1985-01-04

    The circuit was designed for the specific application of wind-driven induction generators. It has great potential for application in any situation where a varying reactive power load is present, such as with induction motors or generators, or for transmission network compensation.

  9. A Tariff for Reactive Power - IEEE

    SciTech Connect

    Kueck, John D; Tufon, Christopher; Isemonger, Alan; Kirby, Brendan J

    2008-11-01

    This paper describes a suggested tariff or payment for the local supply of reactive power from distributed energy resources. The authors consider four sample customers, and estimate the cost of supply of reactive power for each customer. The power system savings from the local supply of reactive power are also estimated for a hypothetical circuit. It is found that reactive power for local voltage regulation could be supplied to the distribution system economically by customers when new inverters are installed. The inverter would be supplied with a power factor of 0.8, and would be capable of local voltage regulation to a schedule supplied by the utility. Inverters are now installed with photovoltaic systems, fuel cells and microturbines, and adjustable-speed motor drives.

  10. Reactive power management and voltage control in deregulated power markets

    NASA Astrophysics Data System (ADS)

    Spangler, Robert G.

    The research that is the subject of this dissertation is about the management of reactive power and voltage support in the wholesale open access power markets in the United States (US). The purpose of this research is to place decisions about open access market structures, as they relate to reactive power and voltage control, on a logical and consistent economic basis, given the engineering needs of a commercial electric power system. An examination of the electricity markets operating in the US today reveals that current approaches to reactive power management and voltage support are extensions of those based on historical, regulated monopoly electric service. A case for change is built by first looking at the subject of reactive power from an engineering viewpoint and then from an economic perspective. Ultimately, a set of market rules for managing reactive power and voltage support is proposed. The proposal suggests that cost recovery for static and dynamic VARs is appropriately accomplished through the regulated transmission cost of service. Static VAR cost recovery should follow traditional rate recovery methodologies. In the case of dynamic VARs, this work provides a methodology based on the microeconomic theory of the firm for determining such cost. It further suggests that an operational strategy that reduces and limits the use of dynamic VARs, during normal operations, is appropriate. This latter point leads to an increase in the fixed cost of the transmission network but prevents price spikes and short supply situations from affecting, or being affected by, the reactive capability limitations associated with dynamic VARs supplied from synchronous generators. The rules are consistent with a market structure that includes competitive generation and their application will result in the communication of a clear understanding of the responsibilities, related to voltage control, of each type of market entity. In this sense, their application will contribute to

  11. Water reactive hydrogen fuel cell power system

    DOEpatents

    Wallace, Andrew P; Melack, John M; Lefenfeld, Michael

    2014-11-25

    A water reactive hydrogen fueled power system includes devices and methods to combine reactant fuel materials and aqueous solutions to generate hydrogen. The generated hydrogen is converted in a fuel cell to provide electricity. The water reactive hydrogen fueled power system includes a fuel cell, a water feed tray, and a fuel cartridge to generate power for portable power electronics. The removable fuel cartridge is encompassed by the water feed tray and fuel cell. The water feed tray is refillable with water by a user. The water is then transferred from the water feed tray into the fuel cartridge to generate hydrogen for the fuel cell which then produces power for the user.

  12. Water reactive hydrogen fuel cell power system

    DOEpatents

    Wallace, Andrew P; Melack, John M; Lefenfeld, Michael

    2014-01-21

    A water reactive hydrogen fueled power system includes devices and methods to combine reactant fuel materials and aqueous solutions to generate hydrogen. The generated hydrogen is converted in a fuel cell to provide electricity. The water reactive hydrogen fueled power system includes a fuel cell, a water feed tray, and a fuel cartridge to generate power for portable power electronics. The removable fuel cartridge is encompassed by the water feed tray and fuel cell. The water feed tray is refillable with water by a user. The water is then transferred from the water feed tray into a fuel cartridge to generate hydrogen for the fuel cell which then produces power for the user.

  13. Local control of reactive power by distributed photovoltaic generators

    SciTech Connect

    Chertkov, Michael; Turitsyn, Konstantin; Sulc, Petr; Backhaus, Scott

    2010-01-01

    High penetration levels of distributed photovoltaic (PV) generation on an electrical distribution circuit may severely degrade power quality due to voltage sags and swells caused by rapidly varying PV generation during cloud transients coupled with the slow response of existing utility compensation and regulation equipment. Although not permitted under current standards for interconnection of distributed generation, fast-reacting, VAR-capable PV inverters may provide the necessary reactive power injection or consumption to maintain voltage regulation under difficult transient conditions. As side benefit, the control of reactive power injection at each PV inverter provides an opportunity and a new tool for distribution utilities to optimize the performance of distribution circuits, e.g. by minimizing thermal losses. We suggest a local control scheme that dispatches reactive power from each PV inverter based on local instantaneous measurements of the real and reactive components of the consumed power and the real power generated by the PVs. Using one adjustable parameter per circuit, we balance the requirements on power quality and desire to minimize thermal losses. Numerical analysis of two exemplary systems, with comparable total PV generation albeit a different spatial distribution, show how to adjust the optimization parameter depending on the goal. Overall, this local scheme shows excellent performance; it's capable of guaranteeing acceptable power quality and achieving significant saving in thermal losses in various situations even when the renewable generation in excess of the circuit own load, i.e. feeding power back to the higher-level system.

  14. Reactive power and harmonic compensation based on the generalized instantaneous reactive power theory for three-phase power systems

    SciTech Connect

    Peng, Fang Zheng; Lai, Jih-Sheng

    1996-10-01

    A generalized theory of instantaneous reactive power for three-phase power systems is proposed in this paper. This theory gives a generalized definition of instantaneous reactive power, which is valid for sinusoidal or nonsinusoidal, balanced or unbalanced, three- phase power systems with or without zero-sequence currents and/or voltages. The properties and physical meanings of the newly defined instantaneous reactive power are discussed in detail. With this new reactive power theory, it is very easy to calculate and decompose all components, such as fundamental active/reactive power and current, harmonic current, etc. Reactive power and/or harmonic compensation systems for a three-phase distorted power system with and without zero-sequence components in the source voltage and/or load current are then used as examples to demonstrate the measurement, decomposition, and compensation of reactive power and harmonics.

  15. Lightweight Regulated Power Supply

    NASA Technical Reports Server (NTRS)

    Mclyman, C. W.

    1985-01-01

    Power-supply circuit regulates output voltage by adjusting frequency of chopper circuit according to variations. Currently installed in battery charger for electric wheelchair, circuit is well suited to other uses in which light weight is important - for example, in portable computers, radios, and test instruments.

  16. Application of Newton's optimal power flow in voltage/reactive power control

    SciTech Connect

    Bjelogrlic, M.; Babic, B.S. ); Calovic, M.S. ); Ristanovic, P. )

    1990-11-01

    This paper considers an application of Newton's optimal power flow to the solution of the secondary voltage/reactive power control in transmission networks. An efficient computer program based on the latest achievements in the sparse matrix/vector techniques has been developed for this purpose. It is characterized by good robustness, accuracy and speed. A combined objective function appropriate for various system load levels with suitable constraints, for treatment of the power system security and economy is also proposed. For the real-time voltage/reactive power control, a suboptimal power flow procedure has been derived by using the reduced set of control variables. This procedure is based on the sensitivity theory applied to the determination of zones for the secondary voltage/reactive power control and corresponding reduced set of regulating sources, whose reactive outputs represent control variables in the optimal power flow program. As a result, the optimal power flow program output becomes a schedule to be used by operators in the process of the real-time voltage/reactive power control in both normal and emergency operating states.

  17. Compensation for Harmonic Currents and Reactive Power in Wind Power Generation System using PWM Inverter

    NASA Astrophysics Data System (ADS)

    Shinohara, Katsuji; Shinhatsubo, Kurato; Iimori, Kenichi; Yamamoto, Kichiro; Saruban, Takamichi; Yamaemori, Takahiro

    In recent year, consciousness of environmental problems is enhancing, and the price of the electric power purchased by an electric power company is established expensive for the power plant utilizing the natural energy. So, the introduction of the wind power generation is promoted in Japan. Generally, squirrel-cage induction machines are widely used as a generator in wind power generation system because of its small size, lightweight and low-cost. However, the induction machines do not have a source of excitation. Thus, it causes the inrush currents and the instantaneous voltage drop when the generator is directly connected to a power grid. To reduce the inrush currents, an AC power regulator is used. Wind power generations are frequently connected to and disconnected from the power grid. However, when the inrush currents are reduced, harmonic currents are caused by phase control of the AC power regulator. And the phase control of AC power regulator cannot control the power factor. Therefore, we propose the use of the AC power regulator to compensate for the harmonic currents and reactive power in the wind power generation system, and demonstrate the validity of its system by simulated and experimental results.

  18. Reactive power optimization using fuzzy load representation

    SciTech Connect

    Abdul-Rahman, K.H.; Shahidehpour, S.M. . Dept. of Electrical and Computer Engineering)

    1994-05-01

    This paper presents a mathematical formulation for the optimal voltage/reactive power control problem taking into account linguistic declaration of system load values. The fuzzy set theory which is based on the feasibility rather than the frequency of occurrence of an outcome is considered, and possibility distributions are assigned to load values and bus voltages. The objective is to minimize power losses considering various load conditions. The problem is decomposed into four subproblems via the Dantzig-Wolfe decomposition for reducing the dimensions of the problem. A second Dantzig-Wolfe decomposition divides each subproblem into several areas leading to a considerable reduction in the dimensions of subproblems. An illustrative example demonstrates the applicability of the approach. The fuzzy approach provides a global solution for the system behavior under various load conditions.

  19. 77 FR 24949 - Reactive Power Resources; Supplemental Notice Requesting Comments

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-26

    ... Energy Regulatory Commission Reactive Power Resources; Supplemental Notice Requesting Comments On April... whether the Commission should reconsider or modify the reactive power provisions of Order No. 661-A and examine what evidence could be developed under Order No. 661 to support a request to apply reactive...

  20. Control circuit maintains unity power factor of reactive load

    NASA Technical Reports Server (NTRS)

    Kramer, M.; Martinage, L. H.

    1966-01-01

    Circuit including feedback control elements automatically corrects the power factor of a reactive load. It maintains power supply efficiency where negative load reactance changes and varies by providing corrective error signals to the control windings of a power supply transformer.

  1. Reactive Power Compensation Using an Energy Management System

    DTIC Science & Technology

    2014-09-01

    Power electronics enabled energy management systems,” in Proceedings of IEEE Applied Power Electronics Conference, Long Beach, CA, Mar. 2013, pp...DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE REACTIVE POWER COMPENSATION USING AN ENERGY MANAGEMENT SYSTEM 5. FUNDING NUMBERS 6. AUTHOR(S...efficiency is the reactive power demand on the grid. Inductive power demand reduces power factor, increases energy losses during transmission, limits real

  2. Reactive high power impulse magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Gudmundsson, J. T.; Magnus, F.; Tryggvason, T. K.; Sveinsson, O. B.; Olafsson, S.

    2012-10-01

    Here we discuss reactive high power impulse magnetron sputtering sputtering (HiPIMS) [1] of Ti target in an Ar/N2 and Ar/O2 atmosphere. The discharge current waveform is highly dependent on both the pulse repetition frequency and discharge voltage. The discharge current increases with decreasing frequency or voltage. This we attribute to an increase in the secondary electron emission yield during the self-sputtering phase of the pulse, as nitride [2] or oxide [3] forms on the target. We also discuss the growth of TiN films on SiO2 at temperatures of 22-600 ^oC. The HiPIMS process produces denser films at lower growth temperature and the surface is much smoother and have a significantly lower resistivity than dc magnetron sputtered films on SiO2 at all growth temperatures due to reduced grain boundary scattering [4].[4pt] [1] J. T. Gudmundsson, N. Brenning, D. Lundin and U. Helmersson, J. Vac. Sci. Technol. A, 30 030801 (2012)[0pt] [2] F. Magnus, O. B. Sveinsson, S. Olafsson and J. T. Gudmundsson, J. Appl. Phys., 110 083306 (2011)[0pt] [3] F. Magnus, T. K. Tryggvason, S. Olafsson and J. T. Gudmundsson, J. Vac. Sci. Technol., submitted 2012[0pt] [4] F. Magnus, A. S. Ingason, S. Olafsson and J. T. Gudmundsson, IEEE Elec. Dev. Lett., accepted 2012

  3. Compensation of Reactive Power of Isolated Wind-Diesel Hybrid Power Systems

    NASA Astrophysics Data System (ADS)

    Sharma, P.; Bhatti, T. S.; Ramakrishna, K. S. S.

    2012-03-01

    This paper presents the automatic reactive power control of an isolated wind-diesel hybrid power system with a synchronous generator (SG) for a diesel genset and an induction generator (IG) with wind energy conversion systems (WECS) to generate electricity. To reduce the gap between reactive power generation and demand, a variable source of reactive power is used such as static synchronous compensator (STATCOM). The mathematical model of the system based on reactive power flow equations is developed. Three examples of the wind-diesel hybrid power systems are considered with different wind power generation capacities to study the effect of the wind power generation on the system performance. The study is based on small signal analysis by considering IEEE type-1 excitation system for the SG. The paper also shows the transient performance of the hybrid systems for 1 % step increase in reactive power load and 1 % step increase in reactive power load plus 1 % step increase in input wind power.

  4. Photovoltaic power regulation system

    SciTech Connect

    Jaster, D.R.

    1986-02-18

    This patent describes a multi-solar module direct current battery charging arrangement consisting of: a group of solar cells; a reverse current blocking diode; a first relay having an energizing winding; and a set of contacts; the diode, the energizing winding and the solar module connected across the battery; a second relay having a second set of contacts; the first relay contacts operate upon a predetermined current flow through the first relay winding to close the first relay and contacts to operate the second relay. A voltage regulator has a set of contacts. The regulator contacts operate upon the battery reaching a predetermined state of charge as indicated by the voltage level; solar cells and a third relay having a set of contacts; the second relay make contacts, the voltage regulator make contacts, the third relay and the second group of solar cells connected in series; the third relay operated upon the second relay operating indicating the solar cells are functioning, and the voltage regulator operating its associated contacts indicating the batteries require further charging to operate the third relay; and the third relay operated to close the associated contacts to connect the second plurality of solar cells across the battery.

  5. Shunt regulation electric power system

    NASA Technical Reports Server (NTRS)

    Wright, W. H.; Bless, J. J. (Inventor)

    1971-01-01

    A regulated electric power system having load and return bus lines is described. A plurality of solar cells interconnected in a power supplying relationship and having a power shunt tap point electrically spaced from the bus lines is provided. A power dissipator is connected to the shunt tap point and provides for a controllable dissipation of excess energy supplied by the solar cells. A dissipation driver is coupled to the power dissipator and controls its conductance and dissipation and is also connected to the solar cells in a power taping relationship to derive operating power therefrom. An error signal generator is coupled to the load bus and to a reference signal generator to provide an error output signal which is representative of the difference between the electric parameters existing at the load bus and the reference signal generator. An error amplifier is coupled to the error signal generator and the dissipation driver to provide the driver with controlling signals.

  6. Local Dynamic Reactive Power for Correction of System Voltage Problems

    SciTech Connect

    Kueck, John D; Rizy, D Tom; Li, Fangxing; Xu, Yan; Li, Huijuan; Adhikari, Sarina; Irminger, Philip

    2008-12-01

    Distribution systems are experiencing outages due to a phenomenon known as local voltage collapse. Local voltage collapse is occurring in part because modern air conditioner compressor motors are much more susceptible to stalling during a voltage dip than older motors. These motors can stall in less than 3 cycles (.05s) when a fault, such as on the sub-transmission system, causes voltage to sag to 70 to 60%. The reasons for this susceptibility are discussed in the report. During the local voltage collapse, voltages are depressed for a period of perhaps one or two minutes. There is a concern that these local events are interacting together over larger areas and may present a challenge to system reliability. An effective method of preventing local voltage collapse is the use of voltage regulation from Distributed Energy Resources (DER) that can supply or absorb reactive power. DER, when properly controlled, can provide a rapid correction to voltage dips and prevent motor stall. This report discusses the phenomenon and causes of local voltage collapse as well as the control methodology we have developed to counter voltage sag. The problem is growing because of the use of low inertia, high efficiency air conditioner (A/C) compressor motors and because the use of electric A/C is growing in use and becoming a larger percentage of system load. A method for local dynamic voltage regulation is discussed which uses reactive power injection or absorption from local DER. This method is independent, rapid, and will not interfere with conventional utility system voltage control. The results of simulations of this method are provided. The method has also been tested at the ORNL s Distributed Energy Communications and Control (DECC) Laboratory using our research inverter and synchronous condenser. These systems at the DECC Lab are interconnected to an actual distribution system, the ORNL distribution system, which is fed from TVA s 161kV sub-transmission backbone. The test results

  7. Reactive power interconnection requirements for PV and wind plants : recommendations to NERC.

    SciTech Connect

    McDowell, Jason; Walling, Reigh; Peter, William; Von Engeln, Edi; Seymour, Eric; Nelson, Robert; Casey, Leo; Ellis, Abraham; Barker, Chris.

    2012-02-01

    Voltage on the North American bulk system is normally regulated by synchronous generators, which typically are provided with voltage schedules by transmission system operators. In the past, variable generation plants were considered very small relative to conventional generating units, and were characteristically either induction generator (wind) or line-commutated inverters (photovoltaic) that have no inherent voltage regulation capability. However, the growing level of penetration of non-traditional renewable generation - especially wind and solar - has led to the need for renewable generation to contribute more significantly to power system voltage control and reactive power capacity. Modern wind-turbine generators, and increasingly PV inverters as well, have considerable dynamic reactive power capability, which can be further enhanced with other reactive support equipment at the plant level to meet interconnection requirements. This report contains a set of recommendations to the North-America Electricity Reliability Corporation (NERC) as part of Task 1-3 (interconnection requirements) of the Integration of Variable Generation Task Force (IVGTF) work plan. The report discusses reactive capability of different generator technologies, reviews existing reactive power standards, and provides specific recommendations to improve existing interconnection standards.

  8. Circuit reactivation dynamically regulates synaptic plasticity in neocortex

    NASA Astrophysics Data System (ADS)

    Kruskal, Peter B.; Li, Lucy; Maclean, Jason N.

    2013-10-01

    Circuit reactivations involve a stereotyped sequence of neuronal firing and have been behaviourally linked to memory consolidation. Here we use multiphoton imaging and patch-clamp recording, and observe sparse and stereotyped circuit reactivations that correspond to UP states within active neurons. To evaluate the effect of the circuit on synaptic plasticity, we trigger a single spike-timing-dependent plasticity (STDP) pairing once per circuit reactivation. The pairings reliably fall within a particular epoch of the circuit sequence and result in long-term potentiation. During reactivation, the amplitude of plasticity significantly correlates with the preceding 20-25 ms of membrane depolarization rather than the depolarization at the time of pairing. This circuit-dependent plasticity provides a natural constraint on synaptic potentiation, regulating the inherent instability of STDP in an assembly phase-sequence model. Subthreshold voltage during endogenous circuit reactivations provides a critical informative context for plasticity and facilitates the stable consolidation of a spatiotemporal sequence.

  9. Voltage Stability Impact of Grid-Tied Photovoltaic Systems Utilizing Dynamic Reactive Power Control

    NASA Astrophysics Data System (ADS)

    Omole, Adedamola

    Photovoltaic (PV) DGs can be optimized to provide reactive power support to the grid, although this feature is currently rarely utilized as most DG systems are designed to operate with unity power factor and supply real power only to the grid. In this work, the voltage stability of a power system embedded with PV DG is examined in the context of the high reactive power requirement after a voltage sag or fault. A real-time dynamic multi-function power controller that enables renewable source PV DGs to provide the reactive power support necessary to maintain the voltage stability of the microgrid, and consequently, the wider power system is proposed. The loadability limit necessary to maintain the voltage stability of an interconnected microgrid is determined by using bifurcation analysis to test for the singularity of the network Jacobian and load differential equations with and without the contribution of the DG. The maximum and minimum real and reactive power support permissible from the DG is obtained from the loadability limit and used as the limiting factors in controlling the real and reactive power contribution from the PV source. The designed controller regulates the voltage output based on instantaneous power theory at the point-of-common coupling (PCC) while the reactive power supply is controlled by means of the power factor and reactive current droop method. The control method is implemented in a modified IEEE 13-bus test feeder system using PSCADRTM power system analysis software and is applied to the model of a Tampa ElectricRTM PV installation at Lowry Park Zoo in Tampa, FL. This dissertation accomplishes the systematic analysis of the voltage impact of a PV DG-embedded power distribution system. The method employed in this work bases the contribution of the PV resource on the voltage stability margins of the microgrid rather than the commonly used loss-of-load probability (LOLP) and effective load-carrying capability (ELCC) measures. The results of

  10. Static reactive power compensators for high-voltage power systems. Final report

    SciTech Connect

    Not Available

    1981-04-01

    A study conducted to summarize the role of static reactive power compensators for high voltage power system applications is described. This information should be useful to the utility system planning engineer in applying static var systems (SVS) to high voltage as (HVAC) systems. The static var system is defined as a form of reactive power compensator. The general need for reactive power compensation in HVAC systems is discussed, and the static var system is compared to other devices utilized to provide reactive power compensation. Examples are presented of applying SVS for specific functions, such as the prevention of voltage collapse. The operating principles of commercially available SVS's are discussed in detail. The perormance and active power loss characteristics of SVS types are compared.

  11. 77 FR 11109 - Reactive Power Resources; Notice of Technical Conference

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-24

    ... interconnecting asynchronous generators and raises questions concerning the need and efficacy of continuing the... by which reactive power is currently secured such as through self-supply; and how a technology that... accessibility@ferc.gov or call toll free 1-866-208- 3372 (voice) or 202-208-8659 (TTY); or send a fax to...

  12. Reactive power in the full Gaussian light wave.

    PubMed

    Seshadri, S R

    2009-11-01

    The electric current sources that are required for the excitation of the fundamental Gaussian beam and the corresponding full Gaussian light wave are determined. The current sources are situated on the secondary source plane that forms the boundary between the two half-spaces in which the waves are launched. The electromagnetic fields and the complex power generated by the current sources are evaluated. For the fundamental Gaussian beam, the reactive power vanishes, and the normalization is chosen such that the real power is 2 W. The various full Gaussian waves are identified by the length parameter b(t) that lies in the range 0 < or = b(t) < or = b, where b is the Rayleigh distance. The other parameters are the wavenumber k, the free-space wavelength lambda, and the beam waist w0 at the input plane. The dependence of the real power of the full Gaussian light wave on b(t)/b and w0/lambda is examined. For a specified w0/lambda, the reactive power, which can be positive or negative, increases as b(t)/b is increased from 0 to 1 and becomes infinite for b(t)/b=1. For a specified b(t)/b, the reactive power approaches zero as kw0 is increased and reaches the limiting value of zero of the paraxial beam.

  13. Osmotic regulation of airway reactivity by epithelium.

    PubMed

    Fedan, J S; Yuan, L X; Chang, V C; Viola, J O; Cutler, D; Pettit, L L

    1999-05-01

    Inhalation of nonisotonic solutions can elicit pulmonary obstruction in asthmatic airways. We evaluated the hypothesis that the respiratory epithelium is involved in responses of the airways to nonisotonic solutions using the guinea pig isolated, perfused trachea preparation to restrict applied agents to the mucosal (intraluminal) or serosal (extraluminal) surface of the airway. In methacholine-contracted tracheae, intraluminally applied NaCl or KCl equipotently caused relaxation that was unaffected by the cyclo-oxygenase inhibitor, indomethacin, but was attenuated by removal of the epithelium and Na+ and Cl- channel blockers. Na+-K+-2Cl- cotransporter and nitric oxide synthase blockers caused a slight inhibition of relaxation, whereas Na+,K+-pump inhibition produced a small potentiation. Intraluminal hyperosmolar KCl and NaCl inhibited contractions in response to intra- or extraluminally applied methacholine, as well as neurogenic cholinergic contractions elicited with electric field stimulation (+/- indomethacin). Extraluminally applied NaCl and KCl elicited epithelium-dependent relaxation (which for KCl was followed by contraction). In contrast to the effects of hyperosmolarity, intraluminal hypo-osmolarity caused papaverine-inhibitable contractions (+/- epithelium). These findings suggest that the epithelium is an osmotic sensor which, through the release of epithelium-derived relaxing factor, can regulate airway diameter by modulating smooth muscle responsiveness and excitatory neurotransmission.

  14. Relation of Emotional Reactivity and Regulation to Childhood Stuttering

    ERIC Educational Resources Information Center

    Karrass, Jan; Walden, Tedra A.; Conture, Edward G.; Graham, Corrin G.; Arnold, Hayley S.; Hartfield, Kia N.; Schwenk, Krista A.

    2006-01-01

    The purpose of the present study was to examine relations between children's emotional reactivity, emotion regulation and stuttering. Participants were 65 preschool children who stutter (CWS) and 56 preschool children who do not stutter (CWNS). Parents completed the Behavior Style Questionnaire (BSQ) [McDevitt S. C., & Carey, W. B. (1978). A…

  15. Reactivity and Regulation in Children Prenatally Exposed to Cocaine

    ERIC Educational Resources Information Center

    Dennis, Tracy; Bendersky, Margaret; Ramsay, Douglas; Lewis, Michael

    2006-01-01

    Children prenatally exposed to cocaine may be at elevated risk for adjustment problems in early development because of greater reactivity and reduced regulation during challenging tasks. Few studies have examined whether cocaine-exposed children show such difficulties during the preschool years, a period marked by increased social and cognitive…

  16. Optimal reactive power control of grid connected photovoltaic resources

    NASA Astrophysics Data System (ADS)

    Trimble, Joshua Ryan

    As more photovoltaic distributed generation resources are installed on distribution power systems, selective control of the inverters connecting the DC power sources presents the opportunity to supply both real and reactive power at the point of common coupling. This thesis presents a simulated distribution system with individually controlled PV resources with the objective of minimizing total system losses while operating at the maximum power point and below the simulated rating of the associated inverters. The control strategy assumes the characteristics of the distribution system are known and solves for the optimal power flow operating point. The ability of each PV source to provide real and reactive power varies instantaneously as irradiance changes, so the operating point for each resource must be constantly recalculated and adjusted. The assumption of known system paramaters can be justified in a SmartGrid context, and a solution based on overall system power flow should be considered as a benchmark for any other state estimation or local control approaches.

  17. Unity power factor switching regulator

    NASA Technical Reports Server (NTRS)

    Rippel, Wally E. (Inventor)

    1983-01-01

    A single or multiphase boost chopper regulator operating with unity power factor, for use such as to charge a battery is comprised of a power section for converting single or multiphase line energy into recharge energy including a rectifier (10), one inductor (L.sub.1) and one chopper (Q.sub.1) for each chopper phase for presenting a load (battery) with a current output, and duty cycle control means (16) for each chopper to control the average inductor current over each period of the chopper, and a sensing and control section including means (20) for sensing at least one load parameter, means (22) for producing a current command signal as a function of said parameter, means (26) for producing a feedback signal as a function of said current command signal and the average rectifier voltage output over each period of the chopper, means (28) for sensing current through said inductor, means (18) for comparing said feedback signal with said sensed current to produce, in response to a difference, a control signal applied to the duty cycle control means, whereby the average inductor current is proportionate to the average rectifier voltage output over each period of the chopper, and instantaneous line current is thereby maintained proportionate to the instantaneous line voltage, thus achieving a unity power factor. The boost chopper is comprised of a plurality of converters connected in parallel and operated in staggered phase. For optimal harmonic suppression, the duty cycles of the switching converters are evenly spaced, and by negative coupling between pairs 180.degree. out-of-phase, peak currents through the switches can be reduced while reducing the inductor size and mass.

  18. Reactive high power impulse magnetron sputtering: combining simulation and experiment

    NASA Astrophysics Data System (ADS)

    Kozak, Tomas; Vlcek, Jaroslav

    2016-09-01

    Reactive high-power impulse magnetron sputtering (HiPIMS) has recently been used for preparation of various oxide films with high application potential, such as TiO2, ZrO2, Ta2O5, HfO2, VO2. Using our patented method of pulsed reactive gas flow control with an optimized reactive gas inlet, we achieved significantly higher deposition rates compared to typical continuous dc magnetron depositions. We have developed a time-dependent model of the reactive HiPIMS. The model includes a depth-resolved description of the sputtered target (featuring sputtering, implantation and knock-on implantation processes) and a parametric description of the discharge plasma (dissociation of reactive gas, ionization and return of sputtered atoms and gas rarefaction). The model uses a combination of experimental and simulation data as input. We have calculated the composition of the target and substrate for several deposition conditions. The simulations predict a reduced compound coverage of the target in HiPIMS compared to the continuous dc sputtering regime which explains the increased deposition rate. The simulations show that an increased dissociation of oxygen in a HiPIMS discharge is beneficial to achieve stoichiometric films on the substrate at high deposition rates.

  19. Redox signaling regulated by electrophiles and reactive sulfur species

    PubMed Central

    Nishida, Motohiro; Kumagai, Yoshito; Ihara, Hideshi; Fujii, Shigemoto; Motohashi, Hozumi; Akaike, Takaaki

    2016-01-01

    Redox signaling is a key modulator of oxidative stress induced by nonspecific insults of biological molecules generated by reactive oxygen species. Current redox biology is revisiting the traditional concept of oxidative stress, such that toxic effects of reactive oxygen species are protected by diverse antioxidant systems upregulated by oxidative stress responses that are physiologically mediated by redox-dependent cell signaling pathways. Redox signaling is thus precisely regulated by endogenous electrophilic substances that are generated from reactive oxygen species and nitric oxide and its derivative reactive species during stress responses. Among electrophiles formed endogenously, 8-nitroguanosine 3',5'-cyclic monophosphate (8-nitro-cGMP) has unique cell signaling functions, and pathways for its biosynthesis, signaling mechanism, and metabolism in cells have been clarified. Reactive sulfur species such as cysteine hydropersulfides that are abundant in cells are likely involved in 8-nitro-cGMP metabolism. These new aspects of redox biology may stimulate innovative and multidisciplinary research in cell and stem cell biology; infectious diseases, cancer, metabolic syndrome, ageing, and neurodegenerative diseases; and other oxidative stress-related disorders. This review focuses on the most recent progress in the biosynthesis, cell signaling, and metabolism of 8-nitro-cGMP, which is a likely target for drug development and lead to discovery of novel therapeutics for many diseases. PMID:27013774

  20. Power-supply regulation by microprocessor

    SciTech Connect

    Sheehan, J.; Langenbach, H.

    1983-01-01

    Many small-magnet power supplies are regulated by using a microprocessor system to generate control voltages to continuously servoregulate each power supply. The power supplies are of very simple design since all regulation and feedback hardware are parts of the microprocessor system. Most of the supplies are bipolar transistor followers, powered by a common unregulated dc power supply and are used to power trim steering magnets on the three NSLS synchrotron rings. Twelve-bit accuracy is obtained using commercially available microprocessor pc cards.

  1. A Preliminary Analysis of the Economics of Using Distributed Energy as a Source of Reactive Power Supply

    SciTech Connect

    Li, Fangxing; Kueck, John D; Rizy, D Tom; King, Thomas F

    2006-04-01

    the best way to allocate the benefit among customers, utilities, transmission companies or RTOs. With the hidden benefits discovered, it will be easier for the policy maker to re-assess the value of reactive power and to form a sound competitive market for this service. Along with the capability of DE to provide local reactive power, a market needs to exist to promote the operation of DE to regulate voltage and net power factor. There are a number of potential benefits that have been identified including capacity relief, loss reduction, improved system reliability, extended equipment life, reduced transport of reactive power from the G&T, and improved local voltage regulation and power factor. An attempt has been made using very simple data and cases to quantify these benefits. Only the model of a larger and more detailed distribution system with DE can truly give a full picture of the benefits that reactive power from local DE can provide.

  2. Reactive Oxygen Species in the Regulation of Stomatal Movements.

    PubMed

    Sierla, Maija; Waszczak, Cezary; Vahisalu, Triin; Kangasjärvi, Jaakko

    2016-07-01

    Guard cells form stomatal pores that optimize photosynthetic carbon dioxide uptake with minimal water loss. Stomatal movements are controlled by complex signaling networks that respond to environmental and endogenous signals. Regulation of stomatal aperture requires coordinated activity of reactive oxygen species (ROS)-generating enzymes, signaling proteins, and downstream executors such as ion pumps, transporters, and plasma membrane channels that control guard cell turgor pressure. Accumulation of ROS in the apoplast and chloroplasts is among the earliest hallmarks of stomatal closure. Subsequent increase in cytoplasmic Ca(2+) concentration governs the activity of multiple kinases that regulate the activity of ROS-producing enzymes and ion channels. In parallel, ROS directly regulate the activity of multiple proteins via oxidative posttranslational modifications to fine-tune guard cell signaling. In this review, we summarize recent advances in the role of ROS in stomatal closure and discuss the importance of ROS in regulation of signal amplification and specificity in guard cells.

  3. Behavioral reactivity to emotion challenge is associated with cortisol reactivity and regulation at 7, 15, and 24 months of age.

    PubMed

    Ursache, Alexandra; Blair, Clancy; Granger, Douglas A; Stifter, Cynthia; Voegtline, Kristin

    2014-04-01

    Emotionally arousing stimuli have been largely unsuccessful in eliciting cortisol responses in young children. Whether or not emotion challenge will elicit a cortisol response, however, may in part be determined by the extent to which the tasks elicit behavioral reactivity and regulation. We examined relations of behavioral reactivity and regulation to emotional arousal in the context of fear and frustration to the cortisol response at 7, 15, and 24 months of age in a low income, rural population based sample of 1,292 families followed longitudinally from birth. At each age, children participated in fear and frustration inducing tasks, and cortisol samples were taken at three time points (before the tasks began, 20 min following peak emotional arousal or after the series of tasks ended, and 40 min after peak arousal or the tasks ended) in order to capture both increases (reactivity) and subsequent decreases (regulation) in the cortisol response. Using multilevel models, we predicted the cortisol response from measures of behavioral reactivity and regulation. At 7 months of age, cortisol reactivity and recovery were related to behavioral reactivity during a frustration-eliciting task and marginally related to behavioral reactivity during a fear-eliciting task. At 15 and 24 months of age, however, cortisol reactivity and recovery were related only to behavioral reactivity during a fear-eliciting task. Results indicate that while behavioral reactivity is predictive of whether or not infants and young children will exhibit a cortisol response to emotionally arousing tasks, behavioral and cortisol reactivity are not necessarily coupled.

  4. Power-MOSFET Voltage Regulator

    NASA Technical Reports Server (NTRS)

    Miller, W. N.; Gray, O. E.

    1982-01-01

    Ninety-six parallel MOSFET devices with two-stage feedback circuit form a high-current dc voltage regulator that also acts as fully-on solid-state switch when fuel-cell out-put falls below regulated voltage. Ripple voltage is less than 20 mV, transient recovery time is less than 50 ms. Parallel MOSFET's act as high-current dc regulator and switch. Regulator can be used wherever large direct currents must be controlled. Can be applied to inverters, industrial furnaces photovoltaic solar generators, dc motors, and electric autos.

  5. Sensitivity-based reactive power control for voltage profile improvement

    SciTech Connect

    Exposito, A.G.; Ramos, J.L.M. . Dept. of Electrical Engineering); Macias, J.L.R. ); Salinas, Y.C.

    1993-08-01

    This paper presents a procedure for dispatching reactive power when voltage deviations are not acceptable. The proposed method, intended for real-time use, determines which control variables are actually effective for solving voltage violations. Efficiency is measured according to sensitivities, current voltage profile and reserve margin of control variables. The selected control variables are rescheduled in proportion to their efficiency coefficients. State-of-the-art sparsity techniques are used to speed-up computation of sensitivities. An example is included to show effectiveness of the method.

  6. Method of measuring reactive acoustic power density in a fluid

    DOEpatents

    Wheatley, J.C.; Swift, G.W.; Migliori, A.

    1985-09-03

    A method for determining reactive acoustic power density level and its direction in a fluid using a single sensor is disclosed. In the preferred embodiment, an apparatus for conducting the method, which is termed a thermoacoustic couple, consists of a stack of thin, spaced apart polymeric plates, selected ones of which include multiple bimetallic thermocouple junctions positioned along opposite end edges thereof. The thermocouple junctions are connected in series in the nature of a thermopile, and are arranged so as to be responsive to small temperature differences between the opposite edges of the plates. The magnitude of the temperature difference, as represented by the magnitude of the electrical potential difference generated by the thermopile, is found to be directly related to the level of acoustic power density in the gas. 5 figs.

  7. Method of measuring reactive acoustic power density in a fluid

    DOEpatents

    Wheatley, John C.; Swift, Gregory W.; Migliori, Albert

    1985-01-01

    A method for determining reactive acoustic power density level and its direction in a fluid using a single sensor is disclosed. In the preferred embodiment, an apparatus for conducting the method, which is termed a thermoacoustic couple, consists of a stack of thin, spaced apart polymeric plates, selected ones of which include multiple bimetallic thermocouple junctions positioned along opposite end edges thereof. The thermocouple junctions are connected in series in the nature of a thermopile, and are arranged so as to be responsive to small temperature differences between the opposite edges of the plates. The magnitude of the temperature difference, as represented by the magnitude of the electrical potential difference generated by the thermopile, is found to be directly related to the level of acoustic power density in the gas.

  8. Reactive oxygen species in regulation of fungal development.

    PubMed

    Gessler, N N; Aver'yanov, A A; Belozerskaya, T A

    2007-10-01

    Reactive oxygen species (ROS) are formed by fungi in the course of metabolic activity. ROS production increases in fungi due to various stress agents such as starvation, light, mechanical damage, and interactions with some other living organisms. Regulation of ROS level appears to be very important during development of the fungal organism. ROS sources in fungal cells, their sensors, and ROS signal transduction pathways are discussed in this review. Antioxidant defense systems in different classes of fungi are characterized in detail. Particular emphasis is placed on ROS functions in interactions of phytopathogenic fungi with plant cells.

  9. Unified active and reactive power modulation of HVDC transmission systems

    NASA Astrophysics Data System (ADS)

    Grund, C. E.; Pohl, R. V.

    1981-11-01

    The power modulation of a high voltage direct current (HVDC) system for stabilization of an ac/dc network was investigated. It was found that simultaneous modulation of both dc current and voltage was more effective than just current modulation by itself, since the dc voltage modulation could be used to minimize the reactive power changes resulting from a change of the dc current. This helps stabilize the ac busbar voltages at the converters, which reduces undesirable load flow changes to voltage dependent ac loads, thus improving the effectiveness of the dc power modulation. This unified modulation control concept was evaluated by means of digital computer studies as well as a special purpose HVDC simulator. Several combined ac/dc power transmission systems were synthesized for testing of different modulation controller concepts. An optimum controller design incorporating a linear quadratic control algorithm with full state feedback was first studied. This provided a basis for comparison of suboptimal controller designs utilizing reduced state feedback and a Kalman filter state reconstruction technique.

  10. 78 FR 77670 - Zero Rate Reactive Power Rate Schedules; Notice Allowing Post-Workshop Comments

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-24

    ... Comments On December 11, 2013, a Commission staff-led workshop explored the mechanics of filing reactive... written comments focused on the mechanics of filing reactive power rate schedules for which there is...

  11. Power and power-to-flow reactivity transfer functions in EBR-II (Experimental Breeder Reactor II) fuel

    SciTech Connect

    Grimm, K.N.; Meneghetti, D. )

    1989-11-01

    Reactivity transfer functions are important in determining the reactivity history during a power transient. Overall nodal transfer functions have been calculated for different subassembly types in the Experimental Breeder Reactor II (EBR-II). Steady-state calculations for temperature changes and, hence, reactivities for power changes have been separated into power and power-to-flow-dependent terms. Axial nodal transfer functions separated into power and power-to-flow-dependent components are reported in this paper for a typical EBR-II fuel pin. This provides an improved understanding of the time dependence of these components in transient situations.

  12. Transient Control of Synchronous Machine Active and Reactive Power in Micro-grid Power Systems

    NASA Astrophysics Data System (ADS)

    Weber, Luke G.

    There are two main topics associated with this dissertation. The first is to investigate phase-to-neutral fault current magnitude occurring in generators with multiple zero-sequence current sources. The second is to design, model, and tune a linear control system for operating a micro-grid in the event of a separation from the electric power system. In the former case, detailed generator, AC8B excitation system, and four-wire electric power system models are constructed. Where available, manufacturers data is used to validate the generator and exciter models. A gain-delay with frequency droop control is used to model an internal combustion engine and governor. The four wire system is connected through a transformer impedance to an infinite bus. Phase-to-neutral faults are imposed on the system, and fault magnitudes analyzed against three-phase faults to gauge their severity. In the latter case, a balanced three-phase system is assumed. The model structure from the former case - but using data for a different generator - is incorporated with a model for an energy storage device and a net load model to form a micro-grid. The primary control model for the energy storage device has a high level of detail, as does the energy storage device plant model in describing the LC filter and transformer. A gain-delay battery and inverter model is used at the front end. The net load model is intended to be the difference between renewable energy sources and load within a micro-grid system that has separated from the grid. Given the variability of both renewable generation and load, frequency and voltage stability are not guaranteed. This work is an attempt to model components of a proposed micro-grid system at the University of Wisconsin Milwaukee, and design, model, and tune a linear control system for operation in the event of a separation from the electric power system. The control module is responsible for management of frequency and active power, and voltage and reactive

  13. Secure provision of reactive power ancillary services in competitive electricity markets

    NASA Astrophysics Data System (ADS)

    El-Samahy, Ismael

    The research work presented in this thesis discusses various complex issues associated with reactive power management and pricing in the context of new operating paradigms in deregulated power systems, proposing appropriate policy solutions. An integrated two-level framework for reactive power management is set forth, which is both suitable for a competitive market and ensures a secure and reliable operation of the associated power system. The framework is generic in nature and can be adopted for any electricity market structure. The proposed hierarchical reactive power market structure comprises two stages: procurement of reactive power resources on a seasonal basis, and real-time reactive power dispatch. The main objective of the proposed framework is to provide appropriate reactive power support from service providers at least cost, while ensuring a secure operation of the power system. The proposed procurement procedure is based on a two-step optimization model. First, the marginal benefits of reactive power supply from each provider, with respect to system security, are obtained by solving a loadability-maximization problem subject to transmission security constraints imposed by voltage and thermal limits. Second, the selected set of generators is determined by solving an optimal power flow (OPF)-based auction. This auction maximizes a societal advantage function comprising generators' offers and their corresponding marginal benefits with respect to system security, and considering all transmission system constraints. The proposed procedure yields the selected set of generators and zonal price components, which would form the basis for seasonal contracts between the system operator and the selected reactive power service providers. The main objective of the proposed reactive power dispatch model is to minimize the total payment burden on the Independent System Operator (ISO), which is associated with reactive power dispatch. The real power generation is

  14. Time resolved ion energy distribution functions of non-reactive and reactive high power impulse magnetron sputtering of titanium

    NASA Astrophysics Data System (ADS)

    Grosse, Katharina; Breilmann, Wolfgang; Maszl, Christian; Benedikt, Jan; von Keudell, Achim

    2016-09-01

    High power impulse magnetron sputtering (HiPIMS) is a technique for thin film deposition and can be operated in reactive and non-reactive mode. The growth rate of HiPIMS in non-reactive mode reduces to 30% compared to direct current magnetron sputtering (dcMS) at same average power. However, the quality of the coatings produced with HiPIMS is excellent which makes these plasmas highly appealing. In reactive mode target poisoning is occurring which changes the plasma dynamics. An advantage of reactive HiPIMS is that it can be operated hysteresis-free which can result in a higher growth rate compared to dcMS. In this work thin films are deposited by a HiPIMS plasma which is generated by short pulses of 100 μs with high power densities in the range of 1 kW/cm2. Ar and Ar/N2 admixtures are used as a working gas to sputter a 2'' titanium target. The particle transport is analysed with time resolved ion energy distribution functions which are measured by a mass spectrometer with a temporal resolution of 2 μs. Phase resolved optical emission spectroscopy is executed to investigate the particle dynamics of different species. The time and energy resolved particle fluxes in non-reactive and reactive mode are compared and implications on the sputter process are discussed.

  15. Advanced configuration of hybrid passive filter for reactive power and harmonic compensation.

    PubMed

    Kececioglu, O Fatih; Acikgoz, Hakan; Sekkeli, Mustafa

    2016-01-01

    Harmonics is one of the major power quality problems for power systems. The harmonics can be eliminated by power filters such as passive, active, and hybrid. In this study, a new passive filter configuration has been improved in addition to the existing passive filter configurations. Conventional hybrid passive filters are not successful to compensate rapidly changing reactive power demand. The proposed configure are capable of compensating both harmonics and reactive power at the same time. Simulation results show that performance of reactive power and harmonic compensation with advanced hybrid passive filter is better than conventional hybrid passive filters.

  16. Advanced Power Regulator Developed for Spacecraft

    NASA Technical Reports Server (NTRS)

    2005-01-01

    The majority of new satellites generate electrical power using photovoltaic solar arrays and store energy in batteries for use during eclipse periods. Careful regulation of battery charging during insolation can greatly increase the expected lifetime of the satellite. The battery charge regulator is usually custom designed for each satellite and its specific mission. Economic competition in the small satellite market requires battery charge regulators that are lightweight, efficient, inexpensive, and modular enough to be used in a wide variety of satellites. A new battery charge regulator topology has been developed at the NASA Lewis Research Center to address these needs. The new regulator topology uses industry-standard dc-dc converters and a unique interconnection to provide size, weight, efficiency, fault tolerance, and modularity benefits over existing systems. A transformer-isolated buck converter is connected such that the high input line is connected in series with the output. This "bypass connection" biases the converter's output onto the solar array voltage. Because of this biasing, the converter only processes the fraction of power necessary to charge the battery above the solar array voltage. Likewise, the same converter hookup can be used to regulate the battery output to the spacecraft power bus with similar fractional power processing. The advantages of this scheme are: 1) Because only a fraction of the power is processed through the dc-dc converter, the single- stage conversion efficiency is 94 to 98 percent; 2) Costly, high-efficiency dc-dc converters are not necessary for high end-to-end system efficiency; 3) The system is highly fault tolerant because the bypass connection will still deliver power if the dc-dc converter fails; and 4) The converters can easily be connected in parallel, allowing higher power systems to be built from a common building block. This new technology will be spaceflight tested in the Photovoltaic Regulator Kit Experiment

  17. Advanced Power Regulator Developed for Spacecraft

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The majority of new satellites generate electrical power using photovoltaic solar arrays and store energy in batteries for use during eclipse periods. Careful regulation of battery charging during insolation can greatly increase the expected lifetime of the satellite. The battery charge regulator is usually custom designed for each satellite and its specific mission. Economic competition in the small satellite market requires battery charge regulators that are lightweight, efficient, inexpensive, and modular enough to be used in a wide variety of satellites. A new battery charge regulator topology has been developed at the NASA Lewis Research Center to address these needs. The new regulator topology uses industry-standard dc-dc converters and a unique interconnection to provide size, weight, efficiency, fault tolerance, and modularity benefits over existing systems. A transformer-isolated buck converter is connected such that the high input line is connected in series with the output. This "bypass connection" biases the converter's output onto the solar array voltage. Because of this biasing, the converter only processes the fraction of power necessary to charge the battery above the solar array voltage. Likewise, the same converter hookup can be used to regulate the battery output to the spacecraft power bus with similar fractional power processing.

  18. Anticipatory regulation of complex power systems

    NASA Astrophysics Data System (ADS)

    Fieno, Thomas Edward

    Electric generation control is performed in a distributed manner to supply power to geographically defined control areas. The goal of generation control is to keep the inadvertent flow of power across a control area's boundary as small as possible. If a difference exists between the power supplied and the power demanded in a control area, the load deficit or surplus would be either borrowed from or stored as the kinetic energy in rotating machines on the grid. This thesis addresses the challenge of matching the power demand of a local area grid with the power delivered by a coal-fired power plant. An anticipatory controller for a model power plant is presented to prescribe the power output into the grid. The control system forecasts what the future demand of the power customers in a control area is likely to be and modifies the fuel input to the power generation facility in order to match the predicted demand. A neural network was found to be an adaptable and robust prediction mechanism for the highly nonlinear data found in the power consumption patterns in a residential area of the Commonwealth Edison grid. The corresponding control schedule of the power plant was tuned to match the anticipated demand using an iterative neural network approach. The use of neural networks and an iterative scheme allows the controller design in this research to be applied to a broad range of control problems. The control methodology presented takes into account limits in the magnitude and rate of control actions. Simulations show that this implementation of anticipatory control of electric power demand is effective and especially well suited to dynamic systems that include a dead time or control limitations. The response of the anticipatory neural network control system was shown to be more energy efficient than feedback control for a typical thermal power regulation facility and to have a much smoother, reduced control effort.

  19. Journey to Flexible, Reliable, Laboratory Platform for Simultaneous Control of Multiple Reactive Power Producing Devices

    SciTech Connect

    Foster, Jason; Rizy, D Tom; Kueck, John D

    2007-01-01

    Herein is discussed the instrumentation and control requirements for achieving the goal of operating multiple Distributed Energy (DE) devices in parallel to regulate local voltage. The process for establishing the flexible laboratory control and data acquisition system that allows for the integration of multiple Distributed Energy (DE) devices in XXXX Laboratory's Distributed Energy - Communications and Controls Laboratory (DECC) is discussed. The DE devices control local distribution system voltage through dynamic reactive power production. Although original efforts were made to control the reactive power (RP) output using information from commercially available meters specifically designed for monitoring and analyzing electric power values, these "intelligent" meters did not provide the flexibility needed. A very flexible and capable real-time monitoring and control system was selected after the evaluation of various methods of data acquisition (DAQ) and control. The purpose of this paper is to describe the DAQ and controls system development. The chosen controller is a commercially available real-time controller from dSPACE. This controller has many excellent features including a very easy programming platform through Simulink and Matlab's Real Time Workshop. The dSPACE system proved to provide both the flexibility and expandability needed to integrate and control the RP producing devices under consideration. The desire was to develop controls with this flexible laboratory instrumentation and controls setup that could be eventually be included in an embedded controller on a DE device. Some experimental results are included that clearly show that some functional control strategies are currently being tested.

  20. New hybrid active power filter for harmonic current suppression and reactive power compensation

    NASA Astrophysics Data System (ADS)

    Biricik, Samet; Cemal Ozerdem, Ozgur; Redif, Soydan; Sezai Dincer, Mustafa

    2016-08-01

    In the case of undistorted and balanced grid voltages, low ratio shunt active power filters (APFs) can give unity power factors and achieve current harmonic cancellation. However, this is not possible when source voltages are distorted and unbalanced. In this study, the cost-effective hybrid active power filter (HAPF) topology for satisfying the requirements of harmonic current suppression and non-active power compensation for industry is presented. An effective strategy is developed to observe the effect of the placement of power capacitors and LC filters with the shunt APF. A new method for alleviating the negative effects of a nonideal grid voltage is proposed that uses a self-tuning filter algorithm with instantaneous reactive power theory. The real-time control of the studied system was achieved with a field-programmable gate array (FPGA) architecture, which was developed using the OPAL-RT system. The performance result of the proposed HAPF system is tested and presented under nonideal supply voltage conditions.

  1. A flexible active and reactive power control strategy for a variable speed constant frequency generating system

    SciTech Connect

    Tang, Y.; Xu, L.

    1995-07-01

    Variable-speed constant-frequency generating systems are used in wind power, hydro power, aerospace, and naval power generations to enhance efficiency and reduce friction. In these applications, an attractive candidate is the slip power recovery system comprising of doubly excited induction machine or doubly excited brushless reluctance machine and PWM converters with a dc link. In this paper, a flexible active and reactive power control strategy is developed, such that the optimal torque-speed profile of the turbine can be followed and overall reactive power can be controlled, while the machine copper losses have been minimized. At the same time, harmonics injected into the power network has also been minimized. In this manner, the system can function as both a high-efficient power generator and a flexible reactive power compensator.

  2. Energy Storage and Reactive Power Compensator in a Large Wind Farm: Preprint

    SciTech Connect

    Muljadi, E.; Butterfield, C. P.; Yinger, R.; Romanowitz, H.

    2003-10-01

    The size of wind farm power systems is increasing, and so is the number of wind farms contributing to the power systems network. The size of wind turbines is also increasing--from less than 1 MW a few years ago to the 2- to 3-MW machines being installed today and the 5-MW machines under development. The interaction of the wind farm, energy storage, reactive power compensation, and the power system network is being investigated. Because the loads and the wind farms' output fluctuate during the day, the use of energy storage and reactive power compensation is ideal for the power system network. Energy storage and reactive power compensation can minimize real/reactive power imbalances that can affect the surrounding power system. In this paper, we will show how the contribution of wind farms affects the power distribution network and how the power distribution network, energy storage, and reactive power compensation interact when the wind changes. We will also investigate the size of the components in relation to each other and to the power system.

  3. Reactive compatibilizer-tracer: A powerful tool for designing, scaling up and optimizing reactive blending processes

    NASA Astrophysics Data System (ADS)

    Ji, Wei-Yun; Feng, Lian-Fang; Zhang, Cai-Liang; Hu, Guo-Hua

    2015-05-01

    A concept of reactive compatibilizer-tracer is developed to study reactive polymer blending processes in a twin screw extruder. It is summarized as follows. Fluorescent moieties such as anthracene are attached to a reactive compatibilizer so that the latter can be served both as a compatibilizer and a tracer. When evaluating its compatibilizing efficiency for a polymer blending system, unlike the polymer components of the blend which are continuously fed to the extruder, the reactive compatibilizer-tracer is added as a pulse. The concentration of the reactive compatibilizer-tracer in the polymer blend at the die exit is measured, in-line and in real time, using probes capable of detecting the signal of the emission of fluorescent moieties of the reactive compatibilizer-tracer. In the meantime, the corresponding size of the dispersed phase domains of the blend is determined off-line. These two pieces of information allow assessing the compatibilizing efficiency of a reactive compatibilizer in a much easier manner and using a much smaller amount of compatibilizer. Consequently, the concept of reactive compatibilizer-tracer can help select most appropriate compatibilizers under real industrial polymer blending conditions as well as scaling up and/or optimizing them.

  4. Duty cycle control in reactive high-power impulse magnetron sputtering of hafnium and niobium

    NASA Astrophysics Data System (ADS)

    Ganesan, R.; Treverrow, B.; Murdoch, B.; Xie, D.; Ross, A. E.; Partridge, J. G.; Falconer, I. S.; McCulloch, D. G.; McKenzie, D. R.; Bilek, M. M. M.

    2016-06-01

    Instabilities in reactive sputtering have technological consequences and have been attributed to the formation of a compound layer on the target surface (‘poisoning’). Here we demonstrate how the duty cycle of high power impulse magnetron sputtering (HiPIMS) can be used to control the surface conditions of Hf and Nb targets. Variations in the time resolved target current characteristics as a function of duty cycle were attributed to gas rarefaction and to the degree of poisoning of the target surface. As the operation transitions from Ar driven sputtering to metal driven sputtering, the secondary electron emission changes and reduces the target current. The target surface transitions smoothly from a poisoned state at low duty cycles to a quasi-metallic state at high duty cycles. Appropriate selection of duty cycle increases the deposition rate, eliminates the need for active regulation of oxygen flow and enables stable reactive deposition of stoichiometric metal oxide films. A model is presented for the reactive HIPIMS process in which the target operates in a partially poisoned mode with different degrees of oxide layer distribution on its surface that depends on the duty cycle. Finally, we show that by tuning the pulse characteristics, the refractive indices of the metal oxides can be controlled without increasing the absorption coefficients, a result important for the fabrication of optical multilayer stacks.

  5. Detonation Ground Soils, & Explosive-Contaminated Metal Have No Reactivity Characteristics Under RCRA Hazardous Waste Regulations

    DTIC Science & Technology

    1994-08-01

    DETONATION GROUND SOILS, & EXPLOSIVE-CONTAMINATED METAL HAVE NO REACTIVITY CHARACTERISTIC UNDER RCRA HAZARDOUS WASTE REGULATIONS Jay L. Bishop, PhD...Metal Have No Reactivity Characteristics Under RCRA Hazardous Waste Regulations 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6

  6. Assessment of the Economic Potential of Microgrids for Reactive Power Supply

    SciTech Connect

    Appen, Jan von; Marnay, Chris; Stadler, Michael; Momber, Ilan; Klapp, David; Scheven, Alexander von

    2011-05-01

    As power generation from variable distributed energy resources (DER) grows, energy flows in the network are changing, increasing the requirements for ancillary services, including voltage support. With the appropriate power converter, DER can provide ancillary services such as frequency control and voltage support. This paper outlines the economic potential of DERs coordinated in a microgrid to provide reactive power and voltage support at its point of common coupling. The DER Customer Adoption Model assesses the costs of providing reactive power, given local utility rules. Depending on the installed DER, the cost minimizing solution for supplying reactive power locally is chosen. Costs include the variable cost of the additional losses and the investment cost of appropriately over-sizing converters or purchasing capacitors. A case study of a large health care building in San Francisco is used to evaluate different revenue possibilities of creating an incentive for microgrids to provide reactive power.

  7. HIF and reactive oxygen species regulate oxidative phosphorylation in cancer.

    PubMed

    Hervouet, Eric; Cízková, Alena; Demont, Jocelyne; Vojtísková, Alena; Pecina, Petr; Franssen-van Hal, Nicole L W; Keijer, Jaap; Simonnet, Hélène; Ivánek, Robert; Kmoch, Stanislav; Godinot, Catherine; Houstek, Josef

    2008-08-01

    A decrease in oxidative phosphorylation (OXPHOS) is characteristic of many cancer types and, in particular, of clear cell renal carcinoma (CCRC) deficient in von Hippel-Lindau (vhl) gene. In the absence of functional pVHL, hypoxia-inducible factor (HIF) 1-alpha and HIF2-alpha subunits are stabilized, which induces the transcription of many genes including those involved in glycolysis and reactive oxygen species (ROS) metabolism. Transfection of these cells with vhl is known to restore HIF-alpha subunit degradation and to reduce glycolytic genes transcription. We show that such transfection with vhl of 786-0 CCRC (which are devoid of HIF1-alpha) also increased the content of respiratory chain subunits. However, the levels of most transcripts encoding OXPHOS subunits were not modified. Inhibition of HIF2-alpha synthesis by RNA interference in pVHL-deficient 786-0 CCRC also restored respiratory chain subunit content and clearly demonstrated a key role of HIF in OXPHOS regulation. In agreement with these observations, stabilization of HIF-alpha subunit by CoCl(2) decreased respiratory chain subunit levels in CCRC cells expressing pVHL. In addition, HIF stimulated ROS production and mitochondrial manganese superoxide dismutase content. OXPHOS subunit content was also decreased by added H(2)O(2.) Interestingly, desferrioxamine (DFO) that also stabilized HIF did not decrease respiratory chain subunit level. While CoCl(2) significantly stimulates ROS production, DFO is known to prevent hydroxyl radical production by inhibiting Fenton reactions. This indicates that the HIF-induced decrease in OXPHOS is at least in part mediated by hydroxyl radical production.

  8. KRIT1 Regulates the Homeostasis of Intracellular Reactive Oxygen Species

    PubMed Central

    Goitre, Luca; Balzac, Fiorella; Degani, Simona; Degan, Paolo; Marchi, Saverio; Pinton, Paolo; Retta, Saverio Francesco

    2010-01-01

    KRIT1 is a gene responsible for Cerebral Cavernous Malformations (CCM), a major cerebrovascular disease characterized by abnormally enlarged and leaky capillaries that predispose to seizures, focal neurological deficits, and fatal intracerebral hemorrhage. Comprehensive analysis of the KRIT1 gene in CCM patients has suggested that KRIT1 functions need to be severely impaired for pathogenesis. However, the molecular and cellular functions of KRIT1 as well as CCM pathogenesis mechanisms are still research challenges. We found that KRIT1 plays an important role in molecular mechanisms involved in the maintenance of the intracellular Reactive Oxygen Species (ROS) homeostasis to prevent oxidative cellular damage. In particular, we demonstrate that KRIT1 loss/down-regulation is associated with a significant increase in intracellular ROS levels. Conversely, ROS levels in KRIT1−/− cells are significantly and dose-dependently reduced after restoration of KRIT1 expression. Moreover, we show that the modulation of intracellular ROS levels by KRIT1 loss/restoration is strictly correlated with the modulation of the expression of the antioxidant protein SOD2 as well as of the transcriptional factor FoxO1, a master regulator of cell responses to oxidative stress and a modulator of SOD2 levels. Furthermore, we show that the KRIT1-dependent maintenance of low ROS levels facilitates the downregulation of cyclin D1 expression required for cell transition from proliferative growth to quiescence. Finally, we demonstrate that the enhanced ROS levels in KRIT1−/− cells are associated with an increased cell susceptibility to oxidative DNA damage and a marked induction of the DNA damage sensor and repair gene Gadd45α, as well as with a decline of mitochondrial energy metabolism. Taken together, our results point to a new model where KRIT1 limits the accumulation of intracellular oxidants and prevents oxidative stress-mediated cellular dysfunction and DNA damage by enhancing the

  9. KRIT1 regulates the homeostasis of intracellular reactive oxygen species.

    PubMed

    Goitre, Luca; Balzac, Fiorella; Degani, Simona; Degan, Paolo; Marchi, Saverio; Pinton, Paolo; Retta, Saverio Francesco

    2010-07-26

    KRIT1 is a gene responsible for Cerebral Cavernous Malformations (CCM), a major cerebrovascular disease characterized by abnormally enlarged and leaky capillaries that predispose to seizures, focal neurological deficits, and fatal intracerebral hemorrhage. Comprehensive analysis of the KRIT1 gene in CCM patients has suggested that KRIT1 functions need to be severely impaired for pathogenesis. However, the molecular and cellular functions of KRIT1 as well as CCM pathogenesis mechanisms are still research challenges. We found that KRIT1 plays an important role in molecular mechanisms involved in the maintenance of the intracellular Reactive Oxygen Species (ROS) homeostasis to prevent oxidative cellular damage. In particular, we demonstrate that KRIT1 loss/down-regulation is associated with a significant increase in intracellular ROS levels. Conversely, ROS levels in KRIT1(-/-) cells are significantly and dose-dependently reduced after restoration of KRIT1 expression. Moreover, we show that the modulation of intracellular ROS levels by KRIT1 loss/restoration is strictly correlated with the modulation of the expression of the antioxidant protein SOD2 as well as of the transcriptional factor FoxO1, a master regulator of cell responses to oxidative stress and a modulator of SOD2 levels. Furthermore, we show that the KRIT1-dependent maintenance of low ROS levels facilitates the downregulation of cyclin D1 expression required for cell transition from proliferative growth to quiescence. Finally, we demonstrate that the enhanced ROS levels in KRIT1(-/-) cells are associated with an increased cell susceptibility to oxidative DNA damage and a marked induction of the DNA damage sensor and repair gene Gadd45alpha, as well as with a decline of mitochondrial energy metabolism. Taken together, our results point to a new model where KRIT1 limits the accumulation of intracellular oxidants and prevents oxidative stress-mediated cellular dysfunction and DNA damage by enhancing the cell

  10. Modeling of the Reactive High Power Impulse Magnetron Sputtering (HiPIMS) process

    NASA Astrophysics Data System (ADS)

    Gudmundsson, Jon Tomas; Lundin, Daniel; Raadu, Michael; Brenning, Nils; Minea, Tiberiu

    2015-09-01

    Reactive high power impulse magnetron sputtering (HiPIMS) provides both a high ionization fraction of the sputtered material and a high dissociation fraction of the molecular gas. We demonstrate this through an ionization region model (IRM) of the reactive Ar/O2 HiPIMS discharge with a titanium target. We explore the influence of oxygen dilution on the discharge properties such as electron density, the ionization fraction of the sputtered vapor and the oxygen dissociation fraction. We discuss the important processes and challenges for more detailed modeling of the reactive HiPIMS discharge. Furthermore, we discuss experimental observations during reactive high power impulse magnetron sputtering sputtering (HiPIMS) of Ti target in Ar/N2 and Ar/O2 atmosphere. The discharge current waveform is highly dependent on the reactive gas flow rate, pulse repetition frequency and discharge voltage. The discharge current increases with decreasing repetition frequency and increasing flowrate of the reactive gas.

  11. Reactive Inkjet Printing: Reactive Inkjet Printing of Biocompatible Enzyme Powered Silk Micro-Rockets (Small 30/2016).

    PubMed

    Gregory, David A; Zhang, Yu; Smith, Patrick J; Zhao, Xiubo; Ebbens, Stephen J

    2016-08-01

    On page 4048, X. Zhao, S. J. Ebbens, and co-workers demonstrate the ability to fabricate biocompatible silk microrockets via reactive inkjet printing. The microrockets are powered by catalase and undergo bubble propulsion in the presence of hydrogen peroxide. Microrockets are capable of swimming in a large variety of media including biological solutions. Inkjet printing allows digital definition of enzyme distribution within the silk scaffold to control rocket directionality.

  12. Emotional reactivity, regulation and childhood stuttering: A behavioral and electrophysiological study

    PubMed Central

    Arnold, Hayley S.; Conture, Edward G.; Key, Alexandra P.F.; Walden, Tedra

    2011-01-01

    The purpose of this preliminary study was to assess whether behavioral and psychophysiological correlates of emotional reactivity and regulation are associated with developmental stuttering, as well as determine the feasibility of these methods in preschool-age children. Nine preschool-age children who stutter (CWS) and nine preschool-age children who do not stutter (CWNS) listened to brief background conversations conveying happy, neutral, and angry emotions (a resolution conversation followed the angry conversation), then produced narratives based on a text-free storybook. Electroencephalograms (EEG) recorded during listening examined cortical correlates of emotional reactivity and regulation. Speech disfluencies and observed emotion regulation were measured during a narrative immediately after each background conversation. Results indicated that decreased use of regulatory strategies is related to more stuttering in children who stutter. However, no significant differences were found in EEG measurements of emotional reactivity and regulation between CWS and CWNS or between emotion elicitation conditions. Findings were taken to suggest that use of regulatory strategies may relate to the fluency of preschool-age children’s speech-language output. Learner Outcomes: The reader will be able to (1) describe emotional reactivity and regulation processes, (2) discuss evidence for or against the relations of emotional reactivity, regulation and stuttering, (3) understand how multiple measures can be used to measure emotional reactivity and regulation. PMID:21276977

  13. Regulation of immune reactivity to collagen in human beings

    SciTech Connect

    Solinger, A.M.; Stobo, J.D.

    1981-08-01

    Denaturated beef collagen was tested for its ability to induce the production of leukocyte inhibition factor among the peripheral blood mononuclear cells from patients with rheumatoid arthritis and normal individuals. Responsiveness, defined as the production of leukocyte inhibition factor sufficient to cause greater than 20% inhibition of leukocyte migration, was significantly (P less than 0.001, X2 . 31.1) associated with HLA-DR4. All HLA-DR4 positive individuals, including subjects without any evidence of synovitis, were collagen responders. There was no significant (P . 0.3) difference in the absolute reactivity of HLA-DR4+ versus HLA-DR4- individuals to respond to another antigen, Candida albicans. Collagen reactivity required interactions between macrophages and T cells and was directed against determinants inherent in the linear polypeptide, (Gly-Pro)n. In 5 normal HLA-DR4- nonresponders tested, absence of discernable reactivity to collagen was associated with the presence of antigen-specific, radiosensitive suppressive T cells. These studies suggest that during the physiologic metabolism of collagen all individuals are exposed to Gly-Pro determinants normally buried in the interstices of the collagen triple helix. In individuals whose major histocompatibility complex contains genes linked to those coding for HLA-DR4, this results in the activation of reactive T cells. Conversely, in individuals lacking these genes, collagen-specific suppressive cells predominate.

  14. On the Sequential Control of ITER Poloidal Field Converters for Reactive Power Reduction

    NASA Astrophysics Data System (ADS)

    Yuan, Hongwen; Fu, Peng; Gao, Ge; Huang, Liansheng; Song, Zhiquan; He, Shiying; Wu, Yanan; Dong, Lin; Wang, Min; Fang, Tongzhen

    2014-12-01

    Sequential control applied to the International Thermonuclear Experimental Reactor (ITER) poloidal field converter system for the purpose of reactive power reduction is the subject of this investigation. Due to the inherent characteristics of thyristor-based phase-controlled converter, the poloidal field converter system consumes a huge amount of reactive power from the grid, which subsequently results in a voltage drop at the 66 kV busbar if no measure is taken. The installation of a static var compensator rated for 750 MVar at the 66 kV busbar is an essential way to compensate reactive power to the grid, which is the most effective measure to solve the problem. However, sequential control of the multi-series converters provides an additional method to improve the natural power factor and thus alleviate the pressure of reactive power demand of the converter system without any additional cost. In the present paper, by comparing with the symmetrical control technique, the advantage of sequential control in reactive power consumption is highlighted. Simulation results based on SIMULINK are found in agreement with the theoretical analysis.

  15. Genetic algorithms for optimal reactive power compensation planning on the national grid system

    NASA Astrophysics Data System (ADS)

    Pilgrim, J. D.

    This work investigates the use of Genetic Algorithms (GAs) for optimal Reactive power Compensation Planning (RCP) of practical power systems. In particular, RCP of the transmission system of England and Wales as owned and operated by National Grid is considered. The GA is used to simultaneously solve both the siting problem---optimisation of the installation of new devices---and the operational problem---optimisation of preventive transformer taps and the controller characteristics of dynamic compensation devices. A computer package called Genetic Compensation Placement (GCP) has been developed which uses an Integer coded GA (IGA) to solve the RCP problem. The RCP problem is implemented as a multi-objective optimisation: in the interests of security, the number of system and operational constraint violations and the deviation of the busbar voltages from the ideal are all minimised for the base (intact) case and the contingent cases. In the interests of cost reduction, the reactive power cost is minimised for the base case. The reactive power cost encompasses the costs incurred from the installation of reactive power sources and the utilisation of new and existing dynamic reactive power compensation devices. GCP is compared to SCORPION (a planning program currently being used by National Grid) which uses a combination of linear programming and heuristic back-tracking. Results are presented for a practical test system developed with the cooperation of National Grid, and it is found that GCP produces solutions that are cheaper than solutions found by SCORPION and perform extremely well: an improvement in voltage profiles, a decrease in complex power mismatches, and a reduction in MVolt Amps-reactive (VAr) utilisation were observed.

  16. A Wolf Pack Algorithm for Active and Reactive Power Coordinated Optimization in Active Distribution Network

    NASA Astrophysics Data System (ADS)

    Zhuang, H. M.; Jiang, X. J.

    2016-08-01

    This paper presents an active and reactive power dynamic optimization model for active distribution network (ADN), whose control variables include the output of distributed generations (DGs), charge or discharge power of energy storage system (ESS) and reactive power from capacitor banks. To solve the high-dimension nonlinear optimization model, a new heuristic swarm intelligent method, namely wolf pack algorithm (WPA) with better global convergence and computational robustness, is adapted so that the network loss minimization can be achieved. In this paper, the IEEE33-bus system is used to show the effectiveness of WPA technique compared with other techniques. Numerical tests on the modified IEEE 33-bus system show that WPA for active and reactive multi-period optimization of ADN is exact and effective.

  17. EV/PHEV Bidirectional Charger Assessment for V2G Reactive Power Operation

    SciTech Connect

    Kisacikoglu, Mithat C; Ozpineci, Burak; Tolbert, Leon M

    2013-01-01

    This paper presents a summary of the available single-phase ac-dc topologies used for EV/PHEV, level-1 and -2 on-board charging and for providing reactive power support to the utility grid. It presents the design motives of single-phase on-board chargers in detail and makes a classification of the chargers based on their future vehicle-to-grid usage. The pros and cons of each different ac-dc topology are discussed to shed light on their suitability for reactive power support. This paper also presents and analyzes the differences between charging-only operation and capacitive reactive power operation that results in increased demand from the dc-link capacitor (more charge/discharge cycles and increased second harmonic ripple current). Moreover, battery state of charge is spared from losses during reactive power operation, but converter output power must be limited below its rated power rating to have the same stress on the dc-link capacitor.

  18. Reactive power planning under high penetration of wind energy using Benders decomposition

    SciTech Connect

    Xu, Yan; Wei, Yanli; Fang, Xin; Li, Fangxing; Azim, Riyasat

    2015-11-05

    This study addresses the optimal allocation of reactive power volt-ampere reactive (VAR) sources under the paradigm of high penetration of wind energy. Reactive power planning (RPP) in this particular condition involves a high level of uncertainty because of wind power characteristic. To properly model wind generation uncertainty, a multi-scenario framework optimal power flow that considers the voltage stability constraint under the worst wind scenario and transmission N 1 contingency is developed. The objective of RPP in this study is to minimise the total cost including the VAR investment cost and the expected generation cost. Therefore RPP under this condition is modelled as a two-stage stochastic programming problem to optimise the VAR location and size in one stage, then to minimise the fuel cost in the other stage, and eventually, to find the global optimal RPP results iteratively. Benders decomposition is used to solve this model with an upper level problem (master problem) for VAR allocation optimisation and a lower problem (sub-problem) for generation cost minimisation. Impact of the potential reactive power support from doubly-fed induction generator (DFIG) is also analysed. Lastly, case studies on the IEEE 14-bus and 118-bus systems are provided to verify the proposed method.

  19. Reactive power planning under high penetration of wind energy using Benders decomposition

    DOE PAGES

    Xu, Yan; Wei, Yanli; Fang, Xin; ...

    2015-11-05

    This study addresses the optimal allocation of reactive power volt-ampere reactive (VAR) sources under the paradigm of high penetration of wind energy. Reactive power planning (RPP) in this particular condition involves a high level of uncertainty because of wind power characteristic. To properly model wind generation uncertainty, a multi-scenario framework optimal power flow that considers the voltage stability constraint under the worst wind scenario and transmission N 1 contingency is developed. The objective of RPP in this study is to minimise the total cost including the VAR investment cost and the expected generation cost. Therefore RPP under this condition ismore » modelled as a two-stage stochastic programming problem to optimise the VAR location and size in one stage, then to minimise the fuel cost in the other stage, and eventually, to find the global optimal RPP results iteratively. Benders decomposition is used to solve this model with an upper level problem (master problem) for VAR allocation optimisation and a lower problem (sub-problem) for generation cost minimisation. Impact of the potential reactive power support from doubly-fed induction generator (DFIG) is also analysed. Lastly, case studies on the IEEE 14-bus and 118-bus systems are provided to verify the proposed method.« less

  20. Nitric Oxide Regulates The Lymphatic Reactivity Following Hemorrhagic Shock Through Atp-Sensitive Potassium Channel.

    PubMed

    Zhang, Li-Min; Qin, Li-Peng; Zhang, Yu-Ping; Zhao, Zi-Gang; Niu, Chun-Yu

    2016-06-01

    Lymphatic reactivity has been shown to exhibit a biphasic change following hemorrhagic shock, and nitric oxide (NO) is involved in this process. However, the precise mechanism responsible for NO regulation of the lymphatic reactivity along with the progression of hemorrhagic shock is unclear. Therefore, the present study was to investigate how NO participates in regulating the shock-induced biphasic changes in lymphatic reactivity and its underlying mechanisms. First, the expressions or contents of inducible NO synthase, nitrite plus nitrate, and elements of cAMP-PKA-KATP and cGMP-PKG-KATP pathway in thoracic ducts tissue were assessed. The results revealed that levels of nitrite plus nitrate, cAMP, cyclic guanosine monophosphate (cGMP), p-PKA, and p-PKG were increased gradually along with the process of shock. Second, the roles of cAMP-PKA-KATP and cGMP-PKG-KATP in NO regulating lymphatic response to gradient substance P were evaluated with an isolated lymphatic perfusion system. The results showed that the NOS substrate (L-Arg), PKA donor (8-Br-cAMP) decreased the reactivity of shock 0.5 h-lymphatics, and that the PKA inhibitor (H-89) and KATP inhibitor (glibenclamide) restrained the effects of L-Arg while glibenclamide abolished the effects of 8-Br-cAMP. Meanwhile, NOS antagonist (L-NAME), protein kinase G (PKG) inhibitor (KT-5823), and soluble guanylate cyclase inhibitor (ODQ) increased the reactivity of shock 2 h-lymphatics, whereas KATP opener (pinacidil) inhibited these elevated effects induced by either L-NAME, ODQ, or KT-5823. Taken together, these results indicate that NO regulation of lymphatic reactivity during shock involves both cAMP-PKA-KATP and cGMP-PKG-KATP pathways. These findings have potential significance for the treatment of hemorrhagic shock through regulating lymphatic reactivity.

  1. A new dynamic voltage restorer with separating active and reactive power circuit design

    NASA Astrophysics Data System (ADS)

    Pai, Fu-Sheng

    2015-05-01

    Conventional dynamic voltage restorers (DVRs) install parallel battery and capacitor sets at the DC bus to supply the required power for voltage sag compensation. However, the reactive power output of a DVR may increase the ripple voltage at the inner DC bus, possibly resulting in a higher operating temperature of the battery and thus decreased battery life. This paper proposes a DVR system that uses a cascade power module to effectively compensate voltage sag. By separating the active and reactive compensation powers, the proposed DVR provides a lower ripple DC link for extending battery life and offers a flexible way to design the capacitor bank. To confirm the effectiveness of the proposed design, theoretical analysis and experimental validation were conducted under various scenarios. Test results confirm the feasibility and practicality of the proposed method.

  2. Examination of a PHEV Bi-Directional Charger System for V2G Reactive Power Compensation

    SciTech Connect

    Kisacikoglu, Mithat C; Ozpineci, Burak; Tolbert, Leon M

    2010-01-01

    Plug-in hybrid electric vehicles (PHEVs) potentially have the capability to fulfill the energy storage needs of the electric grid by supplying ancillary services such as reactive power compensation. However, in order to allow bidirectional power transfer, the PHEV battery charger should be designed to manage such capability. While many different battery chargers have been available since the inception of the first electric vehicles (EVs), an on-board, conductive charger with bidirectional power transferring capability have recently drawn attention due to their inherent advantages in charging accessibility, ease of use and efficiency. In this study, a reactive power compensation case study using the inverter dc-link capacitor is given when a PHEV battery is under charging operation. Finally, the impact of providing these services on the batteries is also explained.

  3. Regulation of folding and photochromic reactivity of terarylenes through a host-guest interaction.

    PubMed

    Nakashima, Takuya; Fujii, Ryosuke; Kawai, Tsuyoshi

    2011-09-19

    The photochromic reactivity of terarylenes is integrated with molecular folding that is controlled through a host-guest interaction. A thieno[3,2,b]pyridine unit is introduced into a photochromic terarylene structure as an aryl unit to form a guest-interacting site. Thienopyridine-containing terarylenes showed solvent-dependent photochromic reactivity in solution. A terarylene moiety that contains two thienopyridyl units showed significantly high photocoloration reactivity as high as 88% of photocyclization quantum yield in methanol, whereas that value was only 24% in hexane. A temperature-dependent (1)H NMR spectroscopic study in different solvents indicated an interconversion between photochromic-reactive and unreactive conformations. In methanol, the intermolecular interaction between terarylene species and the solvent molecule slows the rate of interconversion and increases the population of the photochromic-active form, whereas the unreactive conformation is dominant in hexane. Crystal-structural studies demonstrated the perfect regulation of molecular folding between a photochromic-active form and an unreactive conformation by changing the solvents for recrystallization. Single crystals prepared from solutions in methanol showed reversible photochromic reactivity, whereas recrystallization from solutions in hexane did not show this reactivity. X-ray crystallographic studies of single crystals from solutions in methanol demonstrated that the photochromic molecules bind a solvent methanol molecule at the guest-interacting site to regulate the molecular conformation into a photochromic-active form in collaboration with specific intramolecular interactions, whereas crystals from solutions in hexane possess the photochromic-unreactive conformation.

  4. Optimal reactive power planning for distribution systems considering intermittent wind power using Markov model and genetic algorithm

    NASA Astrophysics Data System (ADS)

    Li, Cheng

    Wind farms, photovoltaic arrays, fuel cells, and micro-turbines are all considered to be Distributed Generation (DG). DG is defined as the generation of power which is dispersed throughout a utility's service territory and either connected to the utility's distribution system or isolated in a small grid. This thesis addresses modeling and economic issues pertaining to the optimal reactive power planning for distribution system with wind power generation (WPG) units. Wind farms are inclined to cause reverse power flows and voltage variations due to the random-like outputs of wind turbines. To deal with this kind of problem caused by wide spread usage of wind power generation, this thesis investigates voltage and reactive power controls in such a distribution system. Consequently static capacitors (SC) and transformer taps are introduced into the system and treated as controllers. For the purpose of getting optimum voltage and realizing reactive power control, the research proposes a proper coordination among the controllers like on-load tap changer (OLTC), feeder-switched capacitors. What's more, in order to simulate its uncertainty, the wind power generation is modeled by the Markov model. In that way, calculating the probabilities for all the scenarios is possible. Some outputs with consecutive and discrete values have been used for transition between successive time states and within state wind speeds. The thesis will describe the method to generate the wind speed time series from the transition probability matrix. After that, utilizing genetic algorithm, the optimal locations of SCs, the sizes of SCs and transformer taps are determined so as to minimize the cost or minimize the power loss, and more importantly improve voltage profiles. The applicability of the proposed method is verified through simulation on a 9-bus system and a 30-bus system respectively. At last, the simulation results indicate that as long as the available capacitors are able to sufficiently

  5. Regulation of hamster splenocyte reactivity to concanavalin A during pregnancy

    SciTech Connect

    Weppner, W.A.; Coggin, J.H. Jr.

    1980-08-15

    The survival to term of mammalian fetuses regardless of their expression of paternal or embryonic developmental antigens suggests that some alteration in the immune capabilities of a female occur during pregnancy. The immunocompetence of female Syrian golden hamsters during pregnancy was investigated with respect to the blastogenic response of spleen cells to the T-cell mitogen concanavalin A (Con A). The blastogenic response of spleen cells from pregnant hamsters during mid- or late gestation is 10% of that observed for spleen cells from age-matched, virgin female animals. The spleen cells from pregnant hamsters are not capable of suppressing the proliferative response of spleen cells from virgin females to Con A. However, the serum from pregnant hamsters, in comparison with serum from virgin female animals, is capable of reducing this mitogenic response. Extensive washing of the splenocytes from pregnant hamsters does reduce the degree of suppression. These results suggest that the hamster is an excellent animal model for the investigation of the mechanism(s) of immune regulation that operate during pregnancy.

  6. Emotional Reactivity and Regulation in Infancy Interact to Predict Executive Functioning in Early Childhood

    ERIC Educational Resources Information Center

    Ursache, Alexandra; Blair, Clancy; Stifter, Cynthia; Voegtline, Kristin

    2013-01-01

    The relation of observed emotional reactivity and regulation in infancy to executive function in early childhood was examined in a prospective longitudinal sample of 1,292 children from predominantly low-income and rural communities. Children participated in a fear eliciting task at ages 7, 15, and 24 months and completed an executive function…

  7. Emotional Reactivity, Regulation and Childhood Stuttering: A Behavioral and Electrophysiological Study

    ERIC Educational Resources Information Center

    Arnold, Hayley S.; Conture, Edward G.; Key, Alexandra P. F.; Walden, Tedra

    2011-01-01

    The purpose of this preliminary study was to assess whether behavioral and psychophysiological correlates of emotional reactivity and regulation are associated with developmental stuttering, as well as determine the feasibility of these methods in preschool-age children. Nine preschool-age children who stutter (CWS) and nine preschool-age children…

  8. The Role of Emotional Reactivity, Self-Regulation, and Puberty in Adolescents' Prosocial Behaviors

    ERIC Educational Resources Information Center

    Carlo, Gustavo; Crockett, Lisa J.; Wolff, Jennifer M.; Beal, Sarah J.

    2012-01-01

    This study was designed to examine the roles of emotional reactivity, self-regulation, and pubertal timing in prosocial behaviors during adolescence. Participants were 850 sixth graders (50 percent female, mean age = 11.03, standard deviation = 0.17) who were followed up at the age of 15. In hierarchical regression models, measures of emotional…

  9. Movable-molybdenum-reflector reactivity experiments for control studies of compact space power reactor concepts

    NASA Technical Reports Server (NTRS)

    Fox, T. A.

    1973-01-01

    An experimental reflector reactivity study was made with a compact cylindrical reactor using a uranyl fluoride - water fuel solution. The reactor was axially unreflected and radially reflected with segments of molybdenum. The reflector segments were displaced incrementally in both the axial and radial dimensions, and the shutdown of each configuration was measured by using the pulsed-neutron source technique. The reactivity effects for axial and radial displacement of reflector segments are tabulated separately and compared. The experiments provide data for control-system studies of compact-space-power-reactor concepts.

  10. New Approach to Optimize the Apfs Placement Based on Instantaneous Reactive Power Theory by Genetic Algorithm

    NASA Astrophysics Data System (ADS)

    Hashemi-Dezaki, Hamed; Mohammadalizadeh-Shabestary, Masoud; Askarian-Abyaneh, Hossein; Rezaei-Jegarluei, Mohammad

    2014-01-01

    In electrical distribution systems, a great amount of power are wasting across the lines, also nowadays power factors, voltage profiles and total harmonic distortions (THDs) of most loads are not as would be desired. So these important parameters of a system play highly important role in wasting money and energy, and besides both consumers and sources are suffering from a high rate of distortions and even instabilities. Active power filters (APFs) are innovative ideas for solving of this adversity which have recently used instantaneous reactive power theory. In this paper, a novel method is proposed to optimize the allocation of APFs. The introduced method is based on the instantaneous reactive power theory in vectorial representation. By use of this representation, it is possible to asses different compensation strategies. Also, APFs proper placement in the system plays a crucial role in either reducing the losses costs and power quality improvement. To optimize the APFs placement, a new objective function has been defined on the basis of five terms: total losses, power factor, voltage profile, THD and cost. Genetic algorithm has been used to solve the optimization problem. The results of applying this method to a distribution network illustrate the method advantages.

  11. Associations between narcissism and emotion regulation difficulties: Respiratory sinus arrhythmia reactivity as a moderator.

    PubMed

    Zhang, Hui; Wang, Zhenhong; You, Xuqun; Lü, Wei; Luo, Yun

    2015-09-01

    The aim of the current study was to examine the direct and interactive effects of two types of narcissism (overt and covert) and respiratory sinus arrhythmia (RSA) reactivity on emotion regulation difficulties in 227 undergraduate students. Overt and covert narcissism and emotion regulation difficulties were assessed with self-report measures (narcissistic personality inventory (NPI)-16, hypersensitive narcissism scale (HSNS), and difficulties in emotion regulation scale (DERS)), and physiological data were measured during the baseline, stress (a public-speaking task), and recovery periods in the laboratory. Results indicated that overt narcissism was negatively related to a lack of emotional awareness and emotional clarity, whereas covert narcissism was positively related to overall emotion regulation difficulties, nonacceptance of emotional responses, impulse control difficulties, limited access to emotion regulation strategies, and a lack of emotional clarity. RSA reactivity in response to a mock job interview moderated the associations between covert narcissism (as a predictor) and overall emotion regulation difficulties and impulse control difficulties (as outcomes). This finding showed that a greater stress-induced RSA decrease may serve as a protective factor and ameliorate the effect of covert narcissism on individuals' emotion regulation difficulties.

  12. STATCOM-Based Wind-Solar-Hydro Electric Power System with Modified Real and Reactive Power Controls

    NASA Astrophysics Data System (ADS)

    Ram Prabhakar, J.; Ragavan, K.

    2014-01-01

    This paper presents a control of distributed generation (DG) system subjected to sudden rise in demand, faults on the distribution feeder and unbalanced load condition. The effects of line to ground faults on the system are investigated and control measures are taken to stabilize the generator speed and to improve voltage quality at the point of common coupling (PCC). The static shunt compensator (STATCOM) is connected at PCC to provide voltage support during sudden demand rise and fault on feeder. Moreover, the STATCOM control is devised such that even during unbalanced load condition the converter current and hydro-turbine-driven induction generator current is balanced. Owing to this, the double power frequency oscillations in the dc-link voltage and torque pulsations in generator can be averted. The STATCOM also supplies reactive power to the load. In addition to this, generation-demand mismatch is moderated using real and reactive power controllers. To demonstrate the performance of the DG system with the said control approach, model of system is simulated in Matlab-Simulink environment and the results are presented.

  13. Neuroticism and responsiveness to error feedback: adaptive self-regulation versus affective reactivity.

    PubMed

    Robinson, Michael D; Moeller, Sara K; Fetterman, Adam K

    2010-10-01

    Responsiveness to negative feedback has been seen as functional by those who emphasize the value of reflecting on such feedback in self-regulating problematic behaviors. On the other hand, the very same responsiveness has been viewed as dysfunctional by its link to punishment sensitivity and reactivity. The present 4 studies, involving 203 undergraduate participants, sought to reconcile such discrepant views in the context of the trait of neuroticism. In cognitive tasks, individuals were given error feedback when they made mistakes. It was found that greater tendencies to slow down following error feedback were associated with higher levels of accuracy at low levels of neuroticism but lower levels of accuracy at high levels of neuroticism. Individual differences in neuroticism thus appear crucial in understanding whether behavioral alterations following negative feedback reflect proactive versus reactive mechanisms and processes. Implications for understanding the processing basis of neuroticism and adaptive self-regulation are discussed.

  14. The unconscious regulation of emotion: nonconscious reappraisal goals modulate emotional reactivity.

    PubMed

    Williams, Lawrence E; Bargh, John A; Nocera, Christopher C; Gray, Jeremy R

    2009-12-01

    People often encounter difficulty when making conscious attempts to regulate their emotions. We propose that nonconscious self-regulatory processes may be of help in these difficult circumstances because nonconscious processes are not subject to the same set of limitations as are conscious processes. Two experiments examined the effects of nonconsciously operating goals on people's emotion regulatory success. In Experiment 1, participants engaged in an anxiety-eliciting task. Participants who had a reappraisal emotion control goal primed and operating nonconsciously achieved the same decrease in physiological reactivity as those explicitly instructed to reappraise. In Experiment 2, the effect of nonconscious reappraisal priming on physiological reactivity was shown to be most pronounced for those who do not habitually use reappraisal strategies. The findings highlight the potential importance of nonconscious goals for facilitating emotional control in complex real-world environments and have implications for contemporary models of emotion regulation.

  15. Infant negative reactivity defines the effects of parent-child synchrony on physiological and behavioral regulation of social stress.

    PubMed

    Pratt, Maayan; Singer, Magi; Kanat-Maymon, Yaniv; Feldman, Ruth

    2015-11-01

    How infants shape their own development has puzzled developmentalists for decades. Recent models suggest that infant dispositions, particularly negative reactivity and regulation, affect outcome by determining the extent of parental effects. Here, we used a microanalytic experimental approach and proposed that infants with varying levels of negative reactivity will be differentially impacted by parent-infant synchrony in predicting physiological and behavioral regulation of increasing social stress during an experimental paradigm. One hundred and twenty-two mother-infant dyads (4-6 months) were observed in the face-to-face still face (SF) paradigm and randomly assigned to three experimental conditions: SF with touch, standard SF, and SF with arms' restraint. Mother-infant synchrony and infant negative reactivity were observed at baseline, and three mechanisms of behavior regulation were microcoded; distress, disengagement, and social regulation. Respiratory sinus arrhythmia baseline, reactivity, and recovery were quantified. Structural equation modeling provided support for our hypothesis. For physiological regulation, infants high in negative reactivity receiving high mother-infant synchrony showed greater vagal withdrawal, which in turn predicted comparable levels of vagal recovery to that of nonreactive infants. In behavioral regulation, only infants low in negative reactivity who received high synchrony were able to regulate stress by employing social engagement cues during the SF phase. Distress was reduced only among calm infants to highly synchronous mothers, and disengagement was lowest among highly reactive infants experiencing high mother-infant synchrony. Findings chart two pathways by which synchrony may bolster regulation in infants of high and low reactivity. Among low reactive infants, synchrony builds a social repertoire for handling interpersonal stress, whereas in highly reactive infants, it constructs a platform for repeated reparation of

  16. Power fluctuations smoothing and regulations in wind turbine generator systems

    NASA Astrophysics Data System (ADS)

    Babazadehrokni, Hamed

    Wind is one of the most popular renewable energy sources and it has the potential to become the biggest energy source in future. Since the wind does not always blow constantly, the output wind power is not constant which may make some problem for the power grid. According to the grid code which is set by independent system operator, ISO, wind turbine generator systems need to follow some standards such as the predetermined acceptable power fluctuations. In order to smooth the output powers, the energy storage system and some power electronics modules are employed. The utilized power electronics modules in the wind turbine system can pursue many different goals, such as maintaining the voltage stability, frequency stability, providing the available and predetermined output active and reactive power. On the other side, the energy storage system can help achieving some of these goals but its main job is to store the extra energy when not needed and release the stored energy when needed. The energy storage system can be designed in different sizes, material and also combination of different energy storage systems (hybrid designs). Combination of power electronics devises and also energy storage system helps the wind turbine systems to smooth the output power according to the provided standards. In addition prediction of wind speed may improve the performance of wind turbine generator systems. In this research study all these three topics are studied and the obtained results are written in 10 papers which 7 of them are published and three of them are under process.

  17. Proactive and Reactive Transmission Power Control for Energy-Efficient On-Body Communications

    PubMed Central

    Vallejo, Mónica; Recas, Joaquín.; Ayala, José L.

    2015-01-01

    In wireless body sensor network (WBSNs), the human body has an important effect on the performance of the communication due to the temporal variations caused and the attenuation and fluctuation of the path loss. This fact suggests that the transmission power must adapt to the current state of the link in a way that it ensures a balance between energy consumption and packet loss. In this paper, we validate our two transmission power level policies (reactive and predictive approaches) using the Castalia simulator. The integration of our experimental measurements in the simulator allows us to easily evaluate complex scenarios, avoiding the difficulties associated with a practical realization. Our results show that both schemes perform satisfactorily, providing overall energy savings of 24% and 22% for a case of study, as compared to the maximum transmission power mode. PMID:25769049

  18. Proactive and reactive transmission power control for energy-efficient on-body communications.

    PubMed

    Vallejo, Mónica; Recas, Joaquín; Ayala, José L

    2015-03-11

    In wireless body sensor network (WBSNs), the human body has an important effect on the performance of the communication due to the temporal variations caused and the attenuation and fluctuation of the path loss. This fact suggests that the transmission power must adapt to the current state of the link in a way that it ensures a balance between energy consumption and packet loss. In this paper, we validate our two transmission power level policies (reactive and predictive approaches) using the Castalia simulator. The integration of our experimental measurements in the simulator allows us to easily evaluate complex scenarios, avoiding the difficulties associated with a practical realization. Our results show that both schemes perform satisfactorily, providing overall energy savings of 24% and 22% for a case of study, as compared to the maximum transmission power mode.

  19. TOR complex 2-Ypk1 signaling regulates actin polarization via reactive oxygen species.

    PubMed

    Niles, Brad J; Powers, Ted

    2014-12-01

    The evolutionarily conserved mTOR complex 2 (mTORC2) signaling pathway is an important regulator of actin cytoskeletal architecture and, as such, is a candidate target for preventing cancer cell motility and invasion. Remarkably, the precise mechanism(s) by which mTORC2 regulates the actin cytoskeleton have remained elusive. Here we show that in budding yeast, TORC2 and its downstream kinase Ypk1 regulate actin polarization by controlling reactive oxygen species (ROS) accumulation. Specifically, we find that TORC2-Ypk1 regulates actin polarization both by vacuole-related ROS, controlled by the phospholipid flippase kinase Fpk1 and sphingolipids, and by mitochondria-mediated ROS, controlled by the PKA subunit Tpk3. In addition, we find that the protein kinase C (Pkc1)/MAPK cascade, a well-established regulator of actin, acts downstream of Ypk1 to regulate ROS, in part by promoting degradation of the oxidative stress responsive repressor, cyclin C. Furthermore, we show that Ypk1 regulates Pkc1 activity through proper localization of Rom2 at the plasma membrane, which is also dependent on Fpk1 and sphingolipids. Together these findings demonstrate important links between TORC2/Ypk1 signaling, Fpk1, sphingolipids, Pkc1, and ROS as regulators of actin and suggest that ROS may play an important role in mTORC2-dependent dysregulation of the actin cytoskeleton in cancer cells.

  20. Fear and anger reactivity trajectories from 4 to 16 months: the roles of temperament, regulation, and maternal sensitivity.

    PubMed

    Braungart-Rieker, Julia M; Hill-Soderlund, Ashley L; Karrass, Jan

    2010-07-01

    Two goals guided this study: (a) describe changes in infant fear and anger reactivity from 4 to 16 months and (b) examine the degree to which infant temperament, attentional regulation, and maternal sensitivity predict reactivity trajectories. Participants included 143 mothers and infants (57% male) who visited the laboratory at 4, 8, 12, and 16 months. Infant reactivity, regulation, and maternal sensitivity were assessed from laboratory situations; infant temperament was rated by mothers on the Infant Behavior Questionnaire (Rothbart, 1981). Hierarchical linear modeling indicated that overall, fear and anger reactivity increased with age, but the rate of increase for fear slowed over time. Maternal ratings of temperamental fear and anger each predicted laboratory ratings of fear and anger reactivity, respectively. Moreover, infants who showed less regulation showed greater fear reactivity and steeper increases in anger reactivity over time. Infants whose mothers were more sensitive showed slower increases in fear reactivity. Findings from this study suggest that it is important to consider both intrinsic and extrinsic factors to gain a better understanding of the processes that may be involved in the development of emotional reactivity systems.

  1. Fear and Anger Reactivity Trajectories from 4 to 16 Months: The Roles of Temperament, Regulation, and Maternal Sensitivity

    ERIC Educational Resources Information Center

    Braungart-Rieker, Julia M.; Hill-Soderlund, Ashley L.; Karrass, Jan

    2010-01-01

    Two goals guided this study: (a) describe changes in infant fear and anger reactivity from 4 to 16 months and (b) examine the degree to which infant temperament, attentional regulation, and maternal sensitivity predict reactivity trajectories. Participants included 143 mothers and infants (57% male) who visited the laboratory at 4, 8, 12, and 16…

  2. Plasma reactivity in high-power impulse magnetron sputtering through oxygen kinetics

    SciTech Connect

    Vitelaru, Catalin; Lundin, Daniel; Brenning, Nils; Minea, Tiberiu

    2013-09-02

    The atomic oxygen metastable dynamics in a Reactive High-Power Impulse Magnetron Sputtering (R-HiPIMS) discharge has been characterized using time-resolved diode laser absorption in an Ar/O{sub 2} gas mixture with a Ti target. Two plasma regions are identified: the ionization region (IR) close to the target and further out the diffusion region (DR), separated by a transition region. The μs temporal resolution allows identifying the main atomic oxygen production and destruction routes, which are found to be very different during the pulse as compared to the afterglow as deduced from their evolution in space and time.

  3. Comparisons of PRD (power-reactivity-decrements) components for various EBR-II configurations

    SciTech Connect

    Meneghetti, D.; Kucera, D.A.

    1986-09-19

    Comparison of detailed calculations of contributions by region and component of the power-reactivity-decrements (PRD) for four differing loading configurations of the Experimental Breeder Reactor-II (EBR-II) are given. The linear components and Doppler components are calculated. The non-linear (primarily subassembly bowing) components are deduced by differences relative to measured total PRD values. Variations in linear components range from about 10% to as much as about 100% depending upon the component. The deduced non-linear components differ both in magnitude and sign as functions of reactor power. Effects of differing assumptions of the nature of the fuel-to-clad interactions upon the PRD components are also calculated.

  4. Maternal Posttraumatic Stress Symptoms and Infant Emotional Reactivity and Emotion Regulation

    PubMed Central

    Enlow, Michelle Bosquet; Kitts, Robert L.; Blood, Emily; Bizarro, Andrea; Hofmeister, Michelle; Wright, Rosalind J.

    2011-01-01

    The current study examined associations between maternal posttraumatic stress disorder (PTSD) symptoms and infant emotional reactivity and emotion regulation during the first year of life in a primarily low-income, urban, ethnic/racial minority sample of 52 mother-infant dyads. Mothers completed questionnaires assessing their own trauma exposure history and current PTSD and depressive symptoms and their infants’ temperament when the infants were 6 months old. Dyads participated in the repeated Still-Face Paradigm (SFP-R) when the infants were 6 months old, and infant affective states were coded for each SFP-R episode. Mothers completed questionnaires assessing infant trauma exposure history and infant current emotional and behavioral symptoms when the infants were 13 months old. Maternal PTSD symptoms predicted infants’ emotion regulation at 6 months as assessed by (a) infant ability to recover from distress during the SFP-R and (b) maternal report of infant rate of recovery from distress/arousal in daily life. Maternal PTSD symptoms also predicted maternal report of infant externalizing, internalizing, and dysregulation symptoms at 13 months. Maternal PTSD was not associated with measures of infant emotional reactivity. Neither maternal depressive symptoms nor infant direct exposure to trauma accounted for the associations between maternal PTSD symptoms and infant outcomes. These findings suggest that maternal PTSD is associated with offspring emotion regulation difficulties as early as infancy. Such difficulties may contribute to increased risk of mental health problems among children of mothers with PTSD. PMID:21862136

  5. The regulation of superoxide generation and nitric oxide synthesis by C-reactive protein.

    PubMed Central

    Ratnam, S; Mookerjea, S

    1998-01-01

    Activated macrophages utilize both reactive oxygen intermediates and reactive oxynitrogen intermediates for defence against microbes. However, simultaneous generation of superoxide (O- 2;) and nitric oxide (NO) could be harmful to host cells due to the production of peroxynitrite, nitrogen dioxide and hydroxyl radicals. Therefore, the regulation of the production of these molecules is critical to host survival. During periods of inflammation or infection, the level of serum C-reactive protein (CRP) increases in many species. Human and rat CRP have been shown to bind and interact with phagocytic cells. Since many of the interactions of CRP involve the binding to the phosphocholine ligand, we studied the role of CRP in O- 2; and NO generation through the modulation of phosphatidylcholine (PC) metabolism in macrophages. This study has shown that, while rat CRP inhibited phorbol myristate acetate- (PMA) induced release of O- 2; by rat macrophages, CRP-treated macrophages released NO in a time- and dose-dependent manner. CRP increased inducible nitric oxide synthase (iNOS) enzyme as well as iNOS mRNA levels in rat macrophages. Tricyclodecan-9-yl-xanthogenate (D609), an inhibitor to PC phospholipase C (PC-PLC), suppressed iNOS induction but enhanced PMA-induced release of O- 2;. These data indicate that an increased level of CRP during periods of inflammation may result in differential regulation of macrophage NADPH oxidase and iNOS activity. Increased hepatic synthesis of CRP may contribute to the mechanism by which phagocytic cells avoid simultaneous O- 2; and NO synthesis, and this could possibly be mediated through the regulation of PC-PLC. Images Figure 4 Figure 5 PMID:9767445

  6. Testing of an Integrated Reactor Core Simulator and Power Conversion System with Simulated Reactivity Feedback

    NASA Technical Reports Server (NTRS)

    Bragg-Sitton, Shannon M.; Hervol, David S.; Godfroy, Thomas J.

    2009-01-01

    A Direct Drive Gas-Cooled (DDG) reactor core simulator has been coupled to a Brayton Power Conversion Unit (BPCU) for integrated system testing at NASA Glenn Research Center (GRC) in Cleveland, OH. This is a closed-cycle system that incorporates an electrically heated reactor core module, turbo alternator, recuperator, and gas cooler. Nuclear fuel elements in the gas-cooled reactor design are replaced with electric resistance heaters to simulate the heat from nuclear fuel in the corresponding fast spectrum nuclear reactor. The thermodynamic transient behavior of the integrated system was the focus of this test series. In order to better mimic the integrated response of the nuclear-fueled system, a simulated reactivity feedback control loop was implemented. Core power was controlled by a point kinetics model in which the reactivity feedback was based on core temperature measurements; the neutron generation time and the temperature feedback coefficient are provided as model inputs. These dynamic system response tests demonstrate the overall capability of a non-nuclear test facility in assessing system integration issues and characterizing integrated system response times and response characteristics.

  7. Testing of an Integrated Reactor Core Simulator and Power Conversion System with Simulated Reactivity Feedback

    NASA Technical Reports Server (NTRS)

    Bragg-Sitton, Shannon M.; Hervol, David S.; Godfroy, Thomas J.

    2010-01-01

    A Direct Drive Gas-Cooled (DDG) reactor core simulator has been coupled to a Brayton Power Conversion Unit (BPCU) for integrated system testing at NASA Glenn Research Center (GRC) in Cleveland, Ohio. This is a closed-cycle system that incorporates an electrically heated reactor core module, turboalternator, recuperator, and gas cooler. Nuclear fuel elements in the gas-cooled reactor design are replaced with electric resistance heaters to simulate the heat from nuclear fuel in the corresponding fast spectrum nuclear reactor. The thermodynamic transient behavior of the integrated system was the focus of this test series. In order to better mimic the integrated response of the nuclear-fueled system, a simulated reactivity feedback control loop was implemented. Core power was controlled by a point kinetics model in which the reactivity feedback was based on core temperature measurements; the neutron generation time and the temperature feedback coefficient are provided as model inputs. These dynamic system response tests demonstrate the overall capability of a non-nuclear test facility in assessing system integration issues and characterizing integrated system response times and response characteristics.

  8. Reciprocal Regulation of Reactive Oxygen Species and Phospho-CREB Regulates Voltage Gated Calcium Channel Expression during Mycobacterium tuberculosis Infection

    PubMed Central

    Selvakumar, Arti; Antony, Cecil; Singhal, Jhalak; Tiwari, Brijendra K.; Singh, Yogendra; Natarajan, Krishnamurthy

    2014-01-01

    Our previous work has demonstrated the roles played by L-type Voltage Gated Calcium Channels (VGCC) in regulating Mycobacterium tuberculosis (M. tb) survival and pathogenesis. Here we decipher mechanisms and pathways engaged by the pathogen to regulate VGCC expression in macrophages. We show that M. tb and its antigen Rv3416 use phospho-CREB (pCREB), Reactive Oxygen Species (ROS), Protein Kinase C (PKC) and Mitogen Activated Protein Kinase (MAPK) to modulate VGCC expression in macrophages. siRNA mediated knockdown of MyD88, IRAK1, IRAK2 or TRAF6 significantly inhibited antigen mediated VGCC expression. Inhibiting Protein Kinase C (PKC) or MEK-ERK1/2 further increased VGCC expression. Interestingly, inhibiting intracellular calcium release upregulated antigen mediated VGCC expression, while inhibiting extracellular calcium influx had no significant effect. siRNA mediated knockdown of transcription factors c-Jun, SOX5 and CREB significantly inhibited Rv3416 mediated VGCC expression. A dynamic reciprocal cross-regulation between ROS and pCREB was observed that in turn governed VGCC expression with ROS playing a limiting role in the process. Further dissection of the mechanisms such as the interplay between ROS and pCREB would improve our understanding of the regulation of VGCC expression during M. tb infection. PMID:24797940

  9. Experience in connecting the power generating units of thermal power plants to automatic secondary frequency regulation within the united power system of Russia

    SciTech Connect

    Zhukov, A. V.; Komarov, A. N.; Safronov, A. N.; Barsukov, I. V.

    2009-05-15

    The principles of central control of the power generating units of thermal power plants by automatic secondary frequency and active power overcurrent regulation systems, and the algorithms for interactions between automatic power control systems for the power production units in thermal power plants and centralized systems for automatic frequency and power regulation, are discussed. The order of switching the power generating units of thermal power plants over to control by a centralized system for automatic frequency and power regulation and by the Central Coordinating System for automatic frequency and power regulation is presented. The results of full-scale system tests of the control of power generating units of the Kirishskaya, Stavropol, and Perm GRES (State Regional Electric Power Plants) by the Central Coordinating System for automatic frequency and power regulation at the United Power System of Russia on September 23-25, 2008, are reported.

  10. Effects of human contact and vagal regulation on pain reactivity and visual attention in newborns.

    PubMed

    Arditi, Hadar; Feldman, Ruth; Eidelman, Arthur I

    2006-11-01

    In two experiments we examined the effects of human contact and vagal regulation on newborns' pain reactivity and visual attention. Baseline cardiac vagal tone was measured during quiet sleep and during the experiment, and vagal withdrawal was indexed as change in vagal tone from baseline to pain (study 1) or attention (study 2). In study 1, 62 healthy newborns were videotaped during a heel-prick procedure and pain reactivity was assessed from micro-level coding of facial expressions, cry behavior, and body movements. Infants were randomly assigned to a contact condition, held by a female assistant, or a no contact condition, on an infant-seat in a similar angle. In study 2, 62 additional healthy newborns, randomly assigned to contact and noncontact conditions, were presented with 2 visual stimuli for a 60 s familiarization period, which were then paired with a novel stimulus. Visual interest, alertness, and novelty preference were coded. Human contact had no effect on the newborns' pain response. Visual attention increased with human contact and newborns in the contact condition looked at the stimuli more frequently, with higher alertness, for longer durations, and had a higher novelty preference. Autonomic reactivity-as indexed by vagal withdrawal-differentiated newborns with intense and mild pain response. Discussion focused on proximity to conspecifics as a contributor to emerging regulatory and adaptive functioning in the human infant.

  11. Voltage Regulator Chip: Power Supplies on a Chip

    SciTech Connect

    2010-09-01

    ADEPT Project: CPES at Virginia Tech is finding ways to save real estate on a computer's motherboard that could be used for other critical functions. Every computer processor today contains a voltage regulator that automatically maintains a constant level of electricity entering the device. These regulators contain bulky components and take up about 30% of a computer's motherboard. CPES at Virginia Tech is developing a voltage regulator that uses semiconductors made of gallium nitride on silicon (GaN-on-Si) and high-frequency soft magnetic material. These materials are integrated on a small, 3D chip that can handle the same amount of power as traditional voltage regulators at 1/10 the size and with improved efficiency. The small size also frees up to 90% of the motherboard space occupied by current voltage regulators.

  12. Regulation of plant reactive oxygen species (ROS) in stress responses: learning from AtRBOHD.

    PubMed

    Liu, Yukun; He, Chengzhong

    2016-05-01

    Reactive oxygen species (ROS) are constantly produced in plants, as the metabolic by-products or as the signaling components in stress responses. High levels of ROS are harmful to plants. In contrast, ROS play important roles in plant physiology, including abiotic and biotic tolerance, development, and cellular signaling. Therefore, ROS production needs to be tightly regulated to balance their function. Respiratory burst oxidase homologue (RBOH) proteins, also known as plant nicotinamide adenine dinucleotide phosphate oxidases, are well studied enzymatic ROS-generating systems in plants. The regulatory mechanisms of RBOH-dependent ROS production in stress responses have been intensively studied. This has greatly advanced our knowledge of the mechanisms that regulate plant ROS production. This review attempts to integrate the regulatory mechanisms of RBOHD-dependent ROS production by discussing the recent advance. AtRBOHD-dependent ROS production could provide a valuable reference for studying ROS production in plant stress responses.

  13. Mitochondrial reactive oxygen species regulate the strength of inhibitory GABA-mediated synaptic transmission

    NASA Astrophysics Data System (ADS)

    Accardi, Michael V.; Daniels, Bryan A.; Brown, Patricia M. G. E.; Fritschy, Jean-Marc; Tyagarajan, Shiva K.; Bowie, Derek

    2014-01-01

    Neuronal communication imposes a heavy metabolic burden in maintaining ionic gradients essential for action potential firing and synaptic signalling. Although cellular metabolism is known to regulate excitatory neurotransmission, it is still unclear whether the brain’s energy supply affects inhibitory signalling. Here we show that mitochondrial-derived reactive oxygen species (mROS) regulate the strength of postsynaptic GABAA receptors at inhibitory synapses of cerebellar stellate cells. Inhibition is strengthened through a mechanism that selectively recruits α3-containing GABAA receptors into synapses with no discernible effect on resident α1-containing receptors. Since mROS promotes the emergence of postsynaptic events with unique kinetic properties, we conclude that newly recruited α3-containing GABAA receptors are activated by neurotransmitter released onto discrete postsynaptic sites. Although traditionally associated with oxidative stress in neurodegenerative disease, our data identify mROS as a putative homeostatic signalling molecule coupling cellular metabolism to the strength of inhibitory transmission.

  14. Fatigability Disrupts Cognitive Processes' Regulation of Inflammatory Reactivity in Old Age

    PubMed Central

    Lin, Feng; Roiland, Rachel; Polesskaya, Oksana; Chapman, Benjamin; Johnson, Melissa; Brasch, Judith; Chen, Ding-Geng; Mapstone, Mark

    2014-01-01

    Objectives High fatigability, a dysfunctional adaption to fatigue, may lead to difficulties performing otherwise regularly encountered cognitive activities and may be related to pro-inflammatory reactivity. The purpose of the study was to investigate the effect of fatigability on cognitive processes and inflammatory response following an acute cognitive stress task in older adults. Design An observational laboratory stress reactivity study. Setting A light- and temperature-controlled laboratory. Participants Fifty-five community-dwelling individuals aged 75 years or older. Measurements We measured interleukin (IL)-6, self-reported acute fatigue, and frontally-oriented cognitive processes as part of a demanding set of cognitive tasks intended to induce stress. Results Subjects were classified into groups of low and high fatigability based on cluster analysis of their self-report acute fatigue before and after the cognitive tasks. The two clusters were comparable on levels of baseline IL-6 and cognitive processes; however, the high fatigability cluster had significantly higher levels of IL-6 response than the low fatigability cluster. After controlling for multiple covariates, fatigability moderated the relationship between speed of processing and IL-6 reactivity. Further exploratory analyses indicated significant adverse associations between speed of processing and attention and IL-6 reactivity in the group with low but not high fatigability. Conclusions While observational, these data are consistent with the notion that pro-inflammatory states in older adults might be reduced by improvements in cognitive processes. Since fatigability was associated with increased acute inflammatory response and disrupted the normal stress regulation provided by the cognitive processes, future randomized studies might examine whether fatigability alleviation reduces IL-6. PMID:24388221

  15. Nonlinear Compensation of Solar Array Simulators with Dual Power Regulation

    NASA Astrophysics Data System (ADS)

    Mizrah, E. A.; Tkachev, S. B.; Poymanov, D. N.; Fedchenko, A. S.

    2016-11-01

    During the tests of the spacecraft electrical systems there is a need for simulators of individual parts of the spacecrafts, in particular, solar array simulators (SAS). One of the topologies of medium and high power SAS simulators has dual control of consumed power and contains series or parallel connected linear and switching regulators. This topology allows to provide wide bandwidth and high efficiency, but the range of the resistance change of periodically switched SAS load is limited to the value of the stabilized attribute. Nonlinear compensator (NC) allows to reduce the average feedback voltage of the switching regulator in case of periodic load switching, which, in turn, allows to increase the average value of the stabilized attribute. The describing function method provides a mathematical description of the NC electrical circuit, which allows to select parameters of NC that eliminate the excitation of self-oscillation based on the SAS load switching frequency range and to study the switching regulator stability.

  16. Emotional Reactivity and Regulation in Anxious and Nonanxious Youth: A Cell-Phone Ecological Momentary Assessment Study

    ERIC Educational Resources Information Center

    Tan, Patricia Z.; Forbes, Erika E.; Dahl, Ronald E.; Ryan, Neal D.; Siegle, Greg J.; Ladouceur, Cecile D.; Silk, Jennifer S.

    2012-01-01

    Background: Reviews have highlighted anxious youths' affective disturbances, specifically, elevated negative emotions and reliance on ineffective emotion regulation strategies. However, no study has examined anxious youth's emotional reactivity and regulation in real-world contexts. Methods: This study utilized an ecological momentary assessment…

  17. Application of fuzzy sets to optimal reactive power planning with security constraints

    SciTech Connect

    Abdul-Rahman, K.H.; Shahidehpour, S.M. . Dept. of Electrical and Computer Engineering)

    1994-05-01

    This paper presents a mathematical formulation for the optimal reactive power planning taking into account the static security constraints and the non-probabilistic uncertainty in load values. The planning process is decomposed into investment and operation problems via the generalized Benders decomposition (GBD). Fixed and variable costs are considered in the investment problem. Linguistic declarations of load values in the operation problem are translated into possibility distribution functions. The operation problem is decomposed into 4 subproblems via Dantzig-Wolfe decomposition (DWD), and the modeling of multi-area power systems is considered by applying a second DWD to each subproblem, leading to a significant reduction in its dimensions for personal computer applications. Voltage constraints within each area are modeled as fuzzy sets for the static security analysis by biasing the final solution towards desired values of variables within their given ranges. The overall solution is a compromise between economics (lower investment and operation costs) and security (tighter feasible region). Numerical examples for the applicability of the proposed approach to multi-area power systems are discussed.

  18. Reactive-power compensation of coal mining excavators by using a new-generation STATCOM

    SciTech Connect

    Bilgin, H.F.; Ermis, M.; Kose, K.N.; Cadirci, I.; Acik, A.; Demirci, T.; Terciyanli, A.; Kocak, C.; Yorukoglu, M.

    2007-01-15

    This paper deals with the development and implementation of a current-source-converter-based static synchronous compensator (CSC-STATCOM) applied to the volt-ampere-reactive (VAR) compensation problem of coal mining excavators. It is composed of a +/- 750-kVAR full-bridge CSC with selective harmonic elimination, a low-pass input filter tuned to 200 Hz, and a Delta/Y-connected coupling transformer for connection to medium-voltage load bus. Each power semiconductor switch is composed of an asymmetrical integrated gate commutated thyristor (IGCT) connected in series with a reverse-blocking diode and switched at 500 Hz to eliminate 5th, 7th, 11th, and 13th current harmonics produced by the CSC. Operating principles, power stage, design of dc link, and input filter are also described in this paper. It has been verified by field tests that the developed STATCOM follows rapid fluctuations in nearly symmetrical lagging and leading VAR consumption of electric excavators, resulting in nearly unity power factor on monthly basis, and the harmonic current spectra in the lines of CSC-STATCOM at the point of common coupling comply with the IEEE Standard 519-1992.

  19. Mitochondrial reactive oxygen species mediate hypoxic down-regulation of hERG channel protein.

    PubMed

    Nanduri, Jayasri; Wang, Ning; Bergson, Pamela; Yuan, Guoxiang; Ficker, Eckhard; Prabhakar, Nanduri R

    2008-08-22

    Previous studies suggest that reactive oxygen species (ROS) play an important role in physiological responses to hypoxia. In the present study, we examined the effects of hypoxia on human ether-a-go-go related gene (hERG) channel protein expression and assessed the role of ROS. Hypoxia, in a stimulus- and time-dependent manner, decreased hERG protein with marked reduction in hERG K+ conductance in human embryonic kidney cells stably expressing the hERG alpha subunit. Down-regulation of hERG by hypoxia was not due to increased proteasomal degradation or decreased transcription but due to decreased synthesis of the protein. Hypoxia increased ROS in a time-dependent manner. Antioxidants prevented hypoxia-evoked down-regulation of hERG protein and exogenous oxidants mimicked the effects of hypoxia. Hypoxia-evoked down-regulation of hERG protein and elevation in ROS were absent in p(O) cells, which are devoid of mitochondrial DNA. Inhibitors of NADPH oxidase failed to prevent the effects of hypoxia. These results demonstrate that hypoxia enhances the production of ROS in the mitochondria, resulting in down-regulation of hERG translation and decreased hERG-mediated K+ conductance.

  20. Regulation control and energy management scheme for wireless power transfer

    SciTech Connect

    Miller, John M.

    2015-12-29

    Power transfer rate at a charging facility can be maximized by employing a feedback scheme. The state of charge (SOC) and temperature of the regenerative energy storage system (RESS) pack of a vehicle is monitored to determine the load due to the RESS pack. An optimal frequency that cancels the imaginary component of the input impedance for the output signal from a grid converter is calculated from the load of the RESS pack, and a frequency offset f* is made to the nominal frequency f.sub.0 of the grid converter output based on the resonance frequency of a magnetically coupled circuit. The optimal frequency can maximize the efficiency of the power transfer. Further, an optimal grid converter duty ratio d* can be derived from the charge rate of the RESS pack. The grid converter duty ratio d* regulates wireless power transfer (WPT) power level.

  1. Standard power regulator for the multi-mission modular spacecraft

    NASA Technical Reports Server (NTRS)

    Kichak, R. A.

    1979-01-01

    The Standard Power Regulator Unit (SPRU) which forms the central building block of the Modular Power Subsystem (MPS) for the Multi-mission Modular Spacecraft (MMS) is described. A functional description of the SPRU is presented, detailing key design features, operational characteristics, and internal redundancy as well as giving block and schematic diagrams for all major subassemblies. The description of a qualification test program consisting of ten sequences ranging from a physical examination of the unit to calculating vibration and sine sweep of power on shock tests is presented. The results showed that some significant anomalies were encountered but no catastrophic failures were indicated, although several power module failures were found due to overvoltage malfunctions of the solar array stimulator.

  2. New Enhanced Artificial Bee Colony (JA-ABC5) Algorithm with Application for Reactive Power Optimization

    PubMed Central

    2015-01-01

    The standard artificial bee colony (ABC) algorithm involves exploration and exploitation processes which need to be balanced for enhanced performance. This paper proposes a new modified ABC algorithm named JA-ABC5 to enhance convergence speed and improve the ability to reach the global optimum by balancing exploration and exploitation processes. New stages have been proposed at the earlier stages of the algorithm to increase the exploitation process. Besides that, modified mutation equations have also been introduced in the employed and onlooker-bees phases to balance the two processes. The performance of JA-ABC5 has been analyzed on 27 commonly used benchmark functions and tested to optimize the reactive power optimization problem. The performance results have clearly shown that the newly proposed algorithm has outperformed other compared algorithms in terms of convergence speed and global optimum achievement. PMID:25879054

  3. Evolving Role of the Power Sector Regulator: A Clean Energy Regulators Initiative Report

    SciTech Connect

    Zinaman, O.; Miller, M.; Bazilian, M.

    2014-04-01

    This paper seeks to briefly characterize the evolving role of power sector regulation. Given current global dynamics, regulation of the power sector is undergoing dramatic changes. This transformation is being driven by various factors including technological advances and cost reductions in renewable energy, energy efficiency, and demand management; increasing air pollution and climate change concerns; and persistent pressure for ensuring sustainable economic development and increased access to energy services by the poor. These issues add to the already complex task of power sector regulation, of which the fundamental remit remains to objectively and transparently ensure least-cost service delivery at high quality. While no single regulatory task is trivial to undertake, it is the prioritization and harmonization of a multitude of objectives that exemplifies the essential challenge of power sector regulation. Evolving regulatory roles can be understood through the concept of existing objectives and an additional layer of emerging objectives. Following this categorization, we describe seven existing objectives of power sector regulators and nine emerging objectives, highlighting key challenges and outlining interdependencies. This essay serves as a preliminary installment in the Clean Energy Regulatory Initiative (CERI) series, and aims to lay the groundwork for subsequent reports and case studies that will explore these topics in more depth.

  4. Biological substrates of emotional reactivity and regulation in adolescence during an emotional go-nogo task

    PubMed Central

    Hare, Todd A.; Tottenham, Nim; Galvan, Adriana; Voss, Henning U.; Glover, Gary H.; Casey, B.J.

    2008-01-01

    Background Adolescence is a transition period from childhood to adulthood that is often characterized by emotional instability. This period is also a time of increased incidence of anxiety and depression underscoring the importance of understanding biological substrates of behavioral and emotion regulation during adolescence. Developmental changes in the brain in concert with individual predispositions for anxiety may underlie the increased risk for poor outcomes reported during adolescence. We tested the hypothesis that difficulties in regulating behavior in emotional contexts in adolescents may be due to competition between heightened activity in subcortical emotional processing systems and immature top-down prefrontal systems. Individual differences in emotional reactivity may put some teens at greater risk during this sensitive transition in development. Methods We examined the association between emotion regulation, and frontoamygdala circuitry in 60 children, adolescents, and adults using an emotional go/nogo paradigm. We went beyond examining the magnitude of neural activity and focused on neural adaptation within this circuitry across time using fMRI. Results Adolescents showed exaggerated amygdala activity relative to children and adults. This age-related difference decreased with repeated exposures to the stimuli, and individual differences in self-ratings of anxiety predicted the extent of adaptation or habituation in amygdala. Individuals with higher trait anxiety showed less habituation over repeated exposures. This failure to habituate was associated with less functional connectivity between ventral prefrontal cortex and amygdala. Conclusions These findings suggest that exaggerated emotional reactivity during adolescence may increase the need for top-down control and put individuals with less control at greater risk for poor outcomes. PMID:18452757

  5. PRD (power-reactivity-decrement) components of a homogeneous U10Zr-fueled 900 MWt LMR

    SciTech Connect

    Meneghetti, D.; Kucera, D.A.

    1988-01-01

    The linear and Doppler feedback components of the regional contributions of the power-reactivity-decrement (PRD) for a representative 900 MWt homogeneous U10Zr-fueled sodium-cooled reactor are calculated. The PRD is the reactivity required to bring the reactor from zero-power hot-critical condition to a given power level. These components are further separated into power dependent and power-to-flow dependent parts. The values are compared with corresponding quantities calculated for the Experimental Breeder Reactor II (EBR-II). The implications of these comparisons upon inherent safety characteristics of metal-fueled sodium-cooled reactors are discussed. The effects of fuel axial restraint on feedback, resulting from possible fuel-clad interactions due to burnup are also calculated. The possible enhancement of desirable feedbacks by use of appropriately designed subassembly-duct bowing feedback characteristics is estimated.

  6. Implications of Carbon Regulation for Green Power Markets

    SciTech Connect

    Bird, Lori; Holt, Ed; Carroll, Ghita

    2007-04-01

    This paper examines the potential effects that emerging mandatory carbon markets have for voluntary markets for renewable energy, or green power markets. In an era of carbon regulation, green power markets will continue to play an important role because many consumers may be interested in supporting renewable energy development beyond what is supported through mandates or other types of policy support. The paper examines the extent to which GHG benefits motivate consumers to make voluntary renewable energy purchases and summarizes key issues emerging as a result of these overlapping markets, such as the implications of carbon regulation for renewable energy marketing claims, the demand for and price of renewable energy certificates (RECs), and the use of RECs in multiple markets (disaggregation of attributes). It describes carbon regulation programs under development in the Northeast and California, and how these might affect renewable energy markets in these regions, as well as the potential interaction between voluntary renewable energy markets and voluntary carbon markets, such as the Chicago Climate Exchange (CCX). It also briefly summarizes the experience in the European Union, where carbon is already regulated. Finally, the paper presents policy options for policymakers and regulators to consider in designing carbon policies to enable carbon markets and voluntary renewable energy markets to work together.

  7. Threat and defense as goal regulation: from implicit goal conflict to anxious uncertainty, reactive approach motivation, and ideological extremism.

    PubMed

    Nash, Kyle; McGregor, Ian; Prentice, Mike

    2011-12-01

    Four studies investigated a goal regulation view of anxious uncertainty threat (Gray & McNaughton, 2000) and ideological defense. Participants (N = 444) were randomly assigned to have achievement or relationship goals implicitly primed. The implicit goal primes were followed by randomly assigned achievement or relationship threats that have reliably caused generalized, reactive approach motivation and ideological defense in past research. The threats caused anxious uncertainty (Study 1), reactive approach motivation (Studies 2 and 3), and reactive ideological conviction (Study 4) only when threat-relevant goals had first been primed, but not when threat-irrelevant goals had first been primed. Reactive ideological conviction (Study 4) was eliminated if participants were given an opportunity to attribute their anxiety to a mundane source. Results support a goal regulation view of anxious uncertainty, threat, and defense with potential for integrating theories of defensive compensation.

  8. Reactivation of L1 retrotransposon by benzo(a)pyrene involves complex genetic and epigenetic regulation.

    PubMed

    Teneng, Ivo; Montoya-Durango, Diego E; Quertermous, James L; Lacy, Mary E; Ramos, Kenneth S

    2011-03-01

    Benzo(a)pyrene (BaP), is an environmental pollutant present in tobacco smoke and a byproduct of fossil fuel combustion which likely contributes to the tumorigenic processes in human cancers including lung and esophageal. Long Interspersed Nuclear Element-1 (LINE-1) or L1 is a mobile element within the mammalian genome that propagates via a "copy-and-paste" mechanism using reverse transcriptase and RNA intermediates. L1 is strongly expressed during early embryogenesis and then silenced as cells initiate differentiation programming. Although the complex transcriptional control mechanisms of L1 are not well understood, L1 reactivation has been described in several human cancers and following exposure of mouse or human cells to BaP. In this study we investigated the molecular mechanisms and epigenetic events that regulate L1 reactivation following BaP exposure. We show that challenge of HeLa cells with BaP induces early enrichment of the transcriptionally-active chromatin markers histone H3 trimethylated at lysine 4 (H3K4Me3) and histone H3 acetylated at lysine 9 (H3K9Ac), and reduces association of DNA methyltransferase-1 (DNMT1) with the L1 promoter. These changes are followed by proteasome-dependent decreases in cellular DNMT1 expression and sustained reduction of cytosine methylation within the L1 promoter CpG island. Pharmacological inhibition of the proteasome signaling pathway with the inhibitor MG132 blocks degradation of DNMT1 and alters BaP-mediated histone epigenetic modifications. We conclude that genetic reactivation of L1 by BaP involves an ordered cascade of epigenetic events that begin with nucleosomal histone modifications and is completed with alterations in DNMT1 recruitment to the L1 promoter and reduced DNA methylation of CpG islands.

  9. Mechanism regulating reactive oxygen species in tumor induced myeloid-derived suppressor cells1

    PubMed Central

    Corzo, Cesar A.; Cotter, Matthew J.; Cheng, Pingyan; Cheng, Fendong; Kusmartsev, Sergei; Sotomayor, Eduardo; Padhya, Tapan; McCaffrey, Thomas V.; McCaffrey, Judith C.; Gabrilovich, Dmitry I.

    2010-01-01

    Myeloid-derived suppressor cells (MDSC) are a major component of the immune suppressive network described in cancer and many other pathological conditions. Recent studies have demonstrated that one of the major mechanisms of MDSC-induced immune suppression is mediated by reactive oxygen species (ROS). However, the mechanism of this phenomenon remained unknown. In this study we observed a substantial up-regulation of ROS by MDSC in all of seven different tumor models and in patients with head and neck cancer. The increased ROS production by MDSC is mediated by up-regulated activity of NADPH oxidase (NOX2). MDSC from tumor-bearing mice had significantly higher expression of NOX2 subunits, primarily p47phox and gp91phox, compared to immature myeloid cells from tumor-free mice. Expression of NOX2 subunits in MDSC was controlled by the STAT3 transcription factor. In the absence of NOX2 activity, MDSC lost the ability to suppress T-cell responses and quickly differentiated into mature macrophages and dendritic cells. These findings expand our fundamental understanding of the biology of MDSC and may also open new opportunities for therapeutic regulation of these cells in cancer. PMID:19380816

  10. Mechanism regulating reactive oxygen species in tumor-induced myeloid-derived suppressor cells.

    PubMed

    Corzo, Cesar A; Cotter, Matthew J; Cheng, Pingyan; Cheng, Fendong; Kusmartsev, Sergei; Sotomayor, Eduardo; Padhya, Tapan; McCaffrey, Thomas V; McCaffrey, Judith C; Gabrilovich, Dmitry I

    2009-05-01

    Myeloid-derived suppressor cells (MDSC) are a major component of the immune suppressive network described in cancer and many other pathological conditions. Recent studies have demonstrated that one of the major mechanisms of MDSC-induced immune suppression is mediated by reactive oxygen species (ROS). However, the mechanism of this phenomenon remained unknown. In this study, we observed a substantial up-regulation of ROS by MDSC in all of seven different tumor models and in patients with head and neck cancer. The increased ROS production by MDSC is mediated by up-regulated activity of NADPH oxidase (NOX2). MDSC from tumor-bearing mice had significantly higher expression of NOX2 subunits, primarily p47(phox) and gp91(phox), compared with immature myeloid cells from tumor-free mice. Expression of NOX2 subunits in MDSC was controlled by the STAT3 transcription factor. In the absence of NOX2 activity, MDSC lost the ability to suppress T cell responses and quickly differentiated into mature macrophages and dendritic cells. These findings expand our fundamental understanding of the biology of MDSC and may also open new opportunities for therapeutic regulation of these cells in cancer.

  11. TRPC3 positively regulates reactive oxygen species driving maladaptive cardiac remodeling

    PubMed Central

    Kitajima, Naoyuki; Numaga-Tomita, Takuro; Watanabe, Masahiko; Kuroda, Takuya; Nishimura, Akiyuki; Miyano, Kei; Yasuda, Satoshi; Kuwahara, Koichiro; Sato, Yoji; Ide, Tomomi; Birnbaumer, Lutz; Sumimoto, Hideki; Mori, Yasuo; Nishida, Motohiro

    2016-01-01

    Reactive oxygen species (ROS) produced by NADPH oxidase 2 (Nox2) function as key mediators of mechanotransduction during both physiological adaptation to mechanical load and maladaptive remodeling of the heart. This is despite low levels of cardiac Nox2 expression. The mechanism underlying the transition from adaptation to maladaptation remains obscure, however. We demonstrate that transient receptor potential canonical 3 (TRPC3), a Ca2+-permeable channel, acts as a positive regulator of ROS (PRROS) in cardiomyocytes, and specifically regulates pressure overload-induced maladaptive cardiac remodeling in mice. TRPC3 physically interacts with Nox2 at specific C-terminal sites, thereby protecting Nox2 from proteasome-dependent degradation and amplifying Ca2+-dependent Nox2 activation through TRPC3-mediated background Ca2+ entry. Nox2 also stabilizes TRPC3 proteins to enhance TRPC3 channel activity. Expression of TRPC3 C-terminal polypeptide abolished TRPC3-regulated ROS production by disrupting TRPC3-Nox2 interaction, without affecting TRPC3-mediated Ca2+ influx. The novel TRPC3 function as a PRROS provides a mechanistic explanation for how diastolic Ca2+ influx specifically encodes signals to induce ROS-mediated maladaptive remodeling and offers new therapeutic possibilities. PMID:27833156

  12. Targeting and Regulation of Reactive Oxygen Species Generation by Nox Family NADPH Oxidases

    PubMed Central

    Morand, Stanislas; Hurt, Darrell; Ueyama, Takehiko

    2009-01-01

    Abstract Nox family NADPH oxidases serve a variety of functions requiring reactive oxygen species (ROS) generation, including antimicrobial defense, biosynthetic processes, oxygen sensing, and redox-based cellular signaling. We explored targeting, assembly, and activation of several Nox family oxidases, since ROS production appears to be regulated both spatially and temporally. Nox1 and Nox3 are similar to the phagocytic (Nox2-based) oxidase, functioning as multicomponent superoxide-generating enzymes. Factors regulating their activities include cytosolic activator and organizer proteins and GTP-Rac. Their regulation varies, with the following rank order: Nox2 > Nox1 > Nox3. Determinants of subcellular targeting include: (a) formation of Nox-p22phox heterodimeric complexes allowing plasma membrane translocation, (b) phospholipids-binding specificities of PX domain-containing organizer proteins (p47phox or Nox organizer 1 (Noxo1 and p40phox), and (c) variably splicing of Noxo1 PX domains directing them to nuclear or plasma membranes. Dual oxidases (Duox1 and Duox2) are targeted by different mechanisms. Plasma membrane targeting results in H2O2 release, not superoxide, to support extracellular peroxidases. Human Duox1 and Duox2 have no demonstrable peroxidase activity, despite their extensive homology with heme peroxidases. The dual oxidases were reconstituted by Duox activator 2 (Duoxa2) or two Duoxa1 variants, which dictate maturation, subcellular localization, and the type of ROS generated by forming stable complexes with Duox. Antioxid Redox Signal. 11, 2607–2619. PMID:19438290

  13. Tubulin cofactor B regulates microtubule densities during microglia transition to the reactive states

    SciTech Connect

    Fanarraga, M.L.

    2009-02-01

    Microglia are highly dynamic cells of the CNS that continuously survey the welfare of the neural parenchyma and play key roles modulating neurogenesis and neuronal cell death. In response to injury or pathogen invasion parenchymal microglia transforms into a more active cell that proliferates, migrates and behaves as a macrophage. The acquisition of these extra skills implicates enormous modifications of the microtubule and actin cytoskeletons. Here we show that tubulin cofactor B (TBCB), which has been found to contribute to various aspects of microtubule dynamics in vivo, is also implicated in microglial cytoskeletal changes. We find that TBCB is upregulated in post-lesion reactive parenchymal microglia/macrophages, in interferon treated BV-2 microglial cells, and in neonate amoeboid microglia where the microtubule densities are remarkably low. Our data demonstrate that upon TBCB downregulation both, after microglia differentiation to the ramified phenotype in vivo and in vitro, or after TBCB gene silencing, microtubule densities are restored in these cells. Taken together these observations support the view that TBCB functions as a microtubule density regulator in microglia during activation, and provide an insight into the understanding of the complex mechanisms controlling microtubule reorganization during microglial transition between the amoeboid, ramified, and reactive phenotypes.

  14. An improved generalized differential evolution algorithm for multi-objective reactive power dispatch

    NASA Astrophysics Data System (ADS)

    Ramesh, S.; Kannan, S.; Baskar, S.

    2012-04-01

    An improved multi-objective generalized differential evolution (I-GDE3) approach to solve optimal reactive power dispatch (ORPD) with multiple and competing objectives is proposed in this article. The objective functions are minimization of real power loss and bus voltage profile improvement. For maintaining good diversity, the concepts of simulated binary crossover (SBX) based recombination and dynamic crowding distance (DCD), are implemented in the GDE3 algorithm. I-GDE3 obtains the Pareto-solution set for ORPD that is impervious to load drifts and perturbations. The performance of the proposed approach is tested in standard IEEE 118-bus and IEEE 300-bus test systems and the result demonstrates the capability of the I-GDE3 algorithm in generating diverse and well distributed Pareto-optimal solutions that are less sensitive to various loading conditions along with load perturbations. The performance of I-GDE3 is compared with respect to multi-objective performance measures namely span, hyper-volume and C-measure. The results show the effectiveness of I-GDE3 and confirm its potential to solve the multi-objective RPD problem.

  15. Current-voltage-time characteristics of the reactive Ar/N{sub 2} high power impulse magnetron sputtering discharge

    SciTech Connect

    Magnus, F.; Sveinsson, O. B.; Olafsson, S.; Gudmundsson, J. T.

    2011-10-15

    The discharge current and voltage waveforms have been measured in a reactive high power impulse magnetron sputtering (HiPIMS) Ar/N{sub 2} discharge with a Ti target for 400 {mu}s long pulses. We observe that the current waveform in the reactive Ar/N{sub 2} HiPIMS discharge is highly dependent on the pulse repetition frequency, unlike the non-reactive Ar discharge. The current is found to increase significantly as the frequency is lowered. This is attributed to an increase in the secondary electron emission yield during the self-sputtering phase, when the nitride forms on the target at low frequencies. In addition, self-sputtering runaway occurs at lower discharge voltages when nitrogen is added to the discharge. This illustrates the crucial role of self-sputtering in the behavior of the reactive HiPIMS discharge.

  16. Power reactivity decrement components of a homogeneous UPu10Zr-fueled 900-MW(thermal) liquid metal reactor

    SciTech Connect

    Meneghetti, D.; Kucera, D.A.

    1989-01-01

    Linear and Doppler feedback components of the power reactivity decrement (PRD) for a 900-MW(thermal) homogeneous UPu10Zr-fueled sodium-cooled reactor have been calculated. (The PRD is the negative of the reactivity required to bring the reactor from a zero-power hot-critical condition to a given power level.) The components are further separated into power-dependent and power-to-flow-dependent parts. These delineations enhance understanding of the contributions of the components to the feedback process. The delineation also enables the PRDs for other values of coolant flows to be estimated. The linear and Doppler components of the PRD are obtained using the EBRPOCO code, which calculates detailed axially delineated contributions of the components for every subassembly of a loading configuration. Separation of the components into power and power-to-flow parts is made by calculations of the components, assuming infinite thermal conductivities to obtain the power-to-flow values. Subtractions of these from the corresponding PRD quantities give the power-dependent parts. The values of the various feedback components are compared with corresponding quantities reported for an analogous U10Zr-fueled case.

  17. 75 FR 29531 - Frequency Regulation Compensation in the Organized Wholesale Power Markets; Supplemental Notice...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-26

    ...] Frequency Regulation Compensation in the Organized Wholesale Power Markets; Supplemental Notice of Technical... conference will provide a forum to consider issues related to frequency regulation compensation in...

  18. Calcium-dependent protein kinases regulate the production of reactive oxygen species by potato NADPH oxidase.

    PubMed

    Kobayashi, Michie; Ohura, Ikuko; Kawakita, Kazuhito; Yokota, Naohiko; Fujiwara, Masayuki; Shimamoto, Ko; Doke, Noriyuki; Yoshioka, Hirofumi

    2007-03-01

    Reactive oxygen species (ROS) are implicated in plant innate immunity. NADPH oxidase (RBOH; for Respiratory Burst Oxidase Homolog) plays a central role in the oxidative burst, and EF-hand motifs in the N terminus of this protein suggest possible regulation by Ca(2+). However, regulatory mechanisms are largely unknown. We identified Ser-82 and Ser-97 in the N terminus of potato (Solanum tuberosum) St RBOHB as potential phosphorylation sites. An anti-phosphopeptide antibody (pSer82) indicated that Ser-82 was phosphorylated by pathogen signals in planta. We cloned two potato calcium-dependent protein kinases, St CDPK4 and St CDPK5, and mass spectrometry analyses showed that these CDPKs phosphorylated only Ser-82 and Ser-97 in the N terminus of St RBOHB in a calcium-dependent manner. Ectopic expression of the constitutively active mutant of St CDPK5, St CDPK5VK, provoked ROS production in Nicotiana benthamiana leaves. The CDPK-mediated ROS production was disrupted by knockdown of Nb RBOHB in N. benthamiana. The loss of function was complemented by heterologous expression of wild-type potato St RBOHB but not by a mutant (S82A/S97A). Furthermore, the heterologous expression of St CDPK5VK phosphorylated Ser-82 of St RBOHB in N. benthamiana. These results suggest that St CDPK5 induces the phosphorylation of St RBOHB and regulates the oxidative burst.

  19. Ethylene response factor 6 is a regulator of reactive oxygen species signaling in Arabidopsis.

    PubMed

    Sewelam, Nasser; Kazan, Kemal; Thomas-Hall, Skye R; Kidd, Brendan N; Manners, John M; Schenk, Peer M

    2013-01-01

    Reactive oxygen species (ROS) are produced in plant cells in response to diverse biotic and abiotic stresses as well as during normal growth and development. Although a large number of transcription factor (TF) genes are up- or down-regulated by ROS, currently very little is known about the functions of these TFs during oxidative stress. In this work, we examined the role of ERF6 (ETHYLENE RESPONSE FACTOR6), an AP2/ERF domain-containing TF, during oxidative stress responses in Arabidopsis. Mutant analyses showed that NADPH oxidase (RbohD) and calcium signaling are required for ROS-responsive expression of ERF6. erf6 insertion mutant plants showed reduced growth and increased H2O2 and anthocyanin levels. Expression analyses of selected ROS-responsive genes during oxidative stress identified several differentially expressed genes in the erf6 mutant. In particular, a number of ROS responsive genes, such as ZAT12, HSFs, WRKYs, MAPKs, RBOHs, DHAR1, APX4, and CAT1 were more strongly induced by H2O2 in erf6 plants than in wild-type. In contrast, MDAR3, CAT3, VTC2 and EX1 showed reduced expression levels in the erf6 mutant. Taken together, our results indicate that ERF6 plays an important role as a positive antioxidant regulator during plant growth and in response to biotic and abiotic stresses.

  20. Negative Regulation of Autophagy by Sulfide Is Independent of Reactive Oxygen Species.

    PubMed

    Laureano-Marín, Ana M; Moreno, Inmaculada; Romero, Luis C; Gotor, Cecilia

    2016-06-01

    Accumulating experimental evidence in mammalian, and recently plant, systems has led to a change in our understanding of the role played by hydrogen sulfide in life processes. In plants, hydrogen sulfide mitigates stress and regulates important plant processes such as photosynthesis, stomatal movement, and autophagy, although the underlying mechanism is not well known. In this study, we provide new experimental evidence that, together with our previous findings, demonstrates the role of hydrogen sulfide in regulating autophagy. We used green fluorescent protein fluorescence associated with autophagic bodies and immunoblot analysis of the ATG8 protein to show that sulfide (and no other molecules such as sulfur-containing molecules or ammonium) was able to inhibit the autophagy induced in Arabidopsis (Arabidopsis thaliana) roots under nitrogen deprivation. Our results showed that sulfide was unable to scavenge reactive oxygen species generated by nitrogen limitation, in contrast to well-established reducers. In addition, reducers were unable to inhibit the accumulation of autophagic bodies and ATG8 protein forms to the same extent as sulfide. Therefore, we conclude that sulfide represses autophagy via a mechanism that is independent of redox conditions.

  1. Glutamate Transporter EAAT2 Expression is Up-Regulated in Reactive Astrocytes in Human Periventricular Leukomalacia

    PubMed Central

    DESILVA, TARA M.; BILLIARDS, SARAID S.; BORENSTEIN, NATALIA S.; TRACHTENBERG, FELICIA L.; VOLPE, JOSEPH J.; KINNEY, HANNAH C.; ROSENBERG, PAUL A.

    2010-01-01

    The major neuropathological correlate of cerebral palsy in premature infants is periventricular leukomalacia (PVL), a disorder of the immature cerebral white matter. Cerebral ischemia leading to excitotoxicity is thought to be important in the pathogenesis of this disorder, implying a critical role for glutamate transporters, the major determinants of extracellular glutamate concentration. Previously, we found that EAAT2 expression is limited primarily to premyelinating oligodendrocytes early in development and is rarely observed in astrocytes until >40 weeks. In this study, we analyzed the expression of EAAT2 in cerebral white matter from PVL and control cases. Western blot analysis suggested an up-regulation of EAAT2 in PVL compared with control cases. Single- and double-label immunocytochemistry showed a significantly higher percentage of EAAT2-immunopositive astrocytes in PVL (51.8% ± 5.6%) compared with control white matter (21.4% ± 5.6%; P = 0.004). Macrophages in the necrotic foci in PVL also expressed EAAT2. Premyelinating oligodendrocytes in both PVL and control cases expressed EAAT2, without qualitative difference in expression. The previously unrecognized up-regulation of EAAT2 in reactive astrocytes and its presence in macrophages in PVL reported here may reflect a response to either hypoxic-ischemic injury or inflammation. PMID:18314905

  2. Insulin regulates glucose consumption and lactate production through reactive oxygen species and pyruvate kinase M2.

    PubMed

    Li, Qi; Liu, Xue; Yin, Yu; Zheng, Ji-Tai; Jiang, Cheng-Fei; Wang, Jing; Shen, Hua; Li, Chong-Yong; Wang, Min; Liu, Ling-Zhi; Jiang, Bing-Hua

    2014-01-01

    Although insulin is known to regulate glucose metabolism and closely associate with liver cancer, the molecular mechanisms still remain to be elucidated. In this study, we attempt to understand the mechanism of insulin in promotion of liver cancer metabolism. We found that insulin increased pyruvate kinase M2 (PKM2) expression through reactive oxygen species (ROS) for regulating glucose consumption and lactate production, key process of glycolysis in hepatocellular carcinoma HepG2 and Bel7402 cells. Interestingly, insulin-induced ROS was found responsible for the suppression of miR-145 and miR-128, and forced expression of either miR-145 or miR-128 was sufficient to abolish insulin-induced PKM2 expression. Furthermore, the knockdown of PKM2 expression also inhibited cancer cell growth and insulin-induced glucose consumption and lactate production, suggesting that PKM2 is a functional downstream effecter of insulin. Taken together, this study would provide a new insight into the mechanism of insulin-induced glycolysis.

  3. Revised seismic and geologic siting regulations for nuclear power plants

    SciTech Connect

    Murphy, A.J.; Chokshi, N.C.

    1997-02-01

    The primary regulatory basis governing the seismic design of nuclear power plants is contained in Appendix A to Part 50, General Design Criteria for Nuclear Power Plants, of Title 10 of the Code of Federal Regulations (CFR). General Design Criteria (GDC) 2 defines requirements for design bases for protection against natural phenomena. GDC 2 states the performance criterion that {open_quotes}Structures, systems, and components important to safety shall be designed to withstand the effects of natural phenomena such as earthquakes, . . . without loss of capability to perform their safety functions. . .{close_quotes}. Appendix A to Part 100, Seismic and Geologic Siting Criteria for Nuclear Power Plants, has been the principal document which provided detailed criteria to evaluate the suitability of proposed sites and suitability of the plant design basis established in consideration of the seismic and geologic characteristics of the proposed sites. Appendix A defines required seismological and geological investigations and requirements for other design conditions such as soil stability, slope stability, and seismically induced floods and water waves, and requirements for seismic instrumentation. The NRC staff is in the process of revising Appendix A. The NRC has recently revised seismic siting and design regulations for future applications. These revisions are discussed in detail in this paper.

  4. DC switching regulated power supply for driving an inductive load

    DOEpatents

    Dyer, George R.

    1986-01-01

    A power supply for driving an inductive load current from a dc power supply hrough a regulator circuit including a bridge arrangement of diodes and switching transistors controlled by a servo controller which regulates switching in response to the load current to maintain a selected load current. First and second opposite legs of the bridge are formed by first and second parallel-connected transistor arrays, respectively, while the third and fourth legs of the bridge are formed by appropriately connected first and second parallel connected diode arrays, respectively. The regulator may be operated in three "stages" or modes: (1) For current runup in the load, both first and second transistor switch arrays are turned "on" and current is supplied to the load through both transistor arrays. (2) When load current reaches the desired level, the first switch is turned "off", and load current "flywheels" through the second switch array and the fourth leg diode array connecting the second switch array in series with the load. Current is maintained by alternating between modes 1 and 2 at a suitable duty cycle and switching rate set by the controller. (3) Rapid current rundown is accomplished by turning both switch arrays "off", allowing load current to be dumped back into the source through the third and fourth diode arrays connecting the source in series opposition with the load to recover energy from the inductive load. The three operating states are controlled automatically by the controller.

  5. DC switching regulated power supply for driving an inductive load

    DOEpatents

    Dyer, G.R.

    1983-11-29

    A dc switching regulated power supply for driving an inductive load is provided. The regulator basic circuit is a bridge arrangement of diodes and transistors. First and second opposite legs of the bridge are formed by first and second parallel-connected transistor arrays, respectively, while the third and fourth legs of the bridge are formed by appropriately connected first and second parallel connected diode arrays, respectively. A dc power supply is connected to the input of the bridge and the output is connected to the load. A servo controller is provided to control the switching rate of the transistors to maintain a desired current to the load. The regulator may be operated in three stages or modes: (1) for current runup in the load, both first and second transistor switch arrays are turned on and current is supplied to the load through both transistor arrays. (2) When load current reaches the desired level, the first switch is turned off, and load current flywheels through the second switch array and the fourth leg diode array connecting the second switch array in series with the load. Current is maintained by alternating between modes 1 and 2 at a suitable duty cycle and switching rate set by the controller. (3) Rapid current rundown is accomplished by turning both switch arrays off, allowing load current to be dumped back into the source through the third and fourth diode arrays connecting the source in series opposition with the load to recover energy from the inductive load.

  6. An underground nuclear power station using self-regulating heat-pipe controlled reactors

    DOEpatents

    Hampel, V.E.

    1988-05-17

    A nuclear reactor for generating electricity is disposed underground at the bottom of a vertical hole that can be drilled using conventional drilling technology. The primary coolant of the reactor core is the working fluid in a plurality of thermodynamically coupled heat pipes emplaced in the hole between the heat source at the bottom of the hole and heat exchange means near the surface of the earth. Additionally, the primary coolant (consisting of the working fluid in the heat pipes in the reactor core) moderates neutrons and regulates their reactivity, thus keeping the power of the reactor substantially constant. At the end of its useful life, the reactor core may be abandoned in place. Isolation from the atmosphere in case of accident or for abandonment is provided by the operation of explosive closures and mechanical valves emplaced along the hole. This invention combines technology developed and tested for small, highly efficient, space-based nuclear electric power plants with the technology of fast- acting closure mechanisms developed and used for underground testing of nuclear weapons. This invention provides a nuclear power installation which is safe from the worst conceivable reactor accident, namely, the explosion of a nuclear weapon near the ground surface of a nuclear power reactor. 5 figs.

  7. Underground nuclear power station using self-regulating heat-pipe controlled reactors

    DOEpatents

    Hampel, Viktor E.

    1989-01-01

    A nuclear reactor for generating electricity is disposed underground at the bottom of a vertical hole that can be drilled using conventional drilling technology. The primary coolant of the reactor core is the working fluid in a plurality of thermodynamically coupled heat pipes emplaced in the hole between the heat source at the bottom of the hole and heat exchange means near the surface of the earth. Additionally, the primary coolant (consisting of the working flud in the heat pipes in the reactor core) moderates neutrons and regulates their reactivity, thus keeping the power of the reactor substantially constant. At the end of its useful life, the reactor core may be abandoned in place. Isolation from the atmosphere in case of accident or for abandonment is provided by the operation of explosive closures and mechanical valves emplaced along the hole. This invention combines technology developed and tested for small, highly efficient, space-based nuclear electric power plants with the technology of fast-acting closure mechanisms developed and used for underground testing of nuclear weapons. This invention provides a nuclear power installation which is safe from the worst conceivable reactor accident, namely, the explosion of a nuclear weapon near the ground surface of a nuclear power reactor.

  8. Regulation of Rac1 and Reactive Oxygen Species Production in Response to Infection of Gastrointestinal Epithelia.

    PubMed

    den Hartog, Gerco; Chattopadhyay, Ranajoy; Ablack, Amber; Hall, Emily H; Butcher, Lindsay D; Bhattacharyya, Asima; Eckmann, Lars; Harris, Paul R; Das, Soumita; Ernst, Peter B; Crowe, Sheila E

    2016-01-01

    Generation of reactive oxygen species (ROS) during infection is an immediate host defense leading to microbial killing. APE1 is a multifunctional protein induced by ROS and after induction, protects against ROS-mediated DNA damage. Rac1 and NAPDH oxidase (Nox1) are important contributors of ROS generation following infection and associated with gastrointestinal epithelial injury. The purpose of this study was to determine if APE1 regulates the function of Rac1 and Nox1 during oxidative stress. Gastric or colonic epithelial cells (wild-type or with suppressed APE1) were infected with Helicobacter pylori or Salmonella enterica and assessed for Rac1 and NADPH oxidase-dependent superoxide production. Rac1 and APE1 interactions were measured by co-immunoprecipitation, confocal microscopy and proximity ligation assay (PLA) in cell lines or in biopsy specimens. Significantly greater levels of ROS were produced by APE1-deficient human gastric and colonic cell lines and primary gastric epithelial cells compared to control cells after infection with either gastric or enteric pathogens. H. pylori activated Rac1 and Nox1 in all cell types, but activation was higher in APE1 suppressed cells. APE1 overexpression decreased H. pylori-induced ROS generation, Rac1 activation, and Nox1 expression. We determined that the effects of APE1 were mediated through its N-terminal lysine residues interacting with Rac1, leading to inhibition of Nox1 expression and ROS generation. APE1 is a negative regulator of oxidative stress in the gastrointestinal epithelium during bacterial infection by modulating Rac1 and Nox1. Our results implicate APE1 in novel molecular interactions that regulate early stress responses elicited by microbial infections.

  9. GASA14 regulates leaf expansion and abiotic stress resistance by modulating reactive oxygen species accumulation.

    PubMed

    Sun, Shulan; Wang, Haoxiang; Yu, Hongmei; Zhong, Chunmei; Zhang, Xiaoxia; Peng, Jianzong; Wang, Xiaojing

    2013-04-01

    Gibberellic acid (GA) can regulate many plant developmental processes. GAST1 has been identified as a GA-stimulated transcript, and Arabidopsis GAST-like genes are known to constitute the GASA family. However, the functions of most GASA genes are not clear at present. In this study, the function of GASA14, a member of the GASA family, was investigated. GASA14 expression was upregulated by GA and downregulated by the transcriptional regulators that repress GA responses, the DELLA proteins GAI and RGA. Phenotypic analysis showed that growth of the GASA14 null mutant (gasa14-1) line was retarded, and the growth of the 35S::GASA14 lines were promoted in young plants. Furthermore, seed germination of the gasa14-1 plants showed more sensitivity to paclobutrazol (an inhibitor of GA biosynthesis) than Columbia (Col) plants, suggesting that GASA14 is required for GA-dependent responses. Analysis of the responses of the gasa14-1 and 35S::GASA14 lines to abscisic acid (ABA) and salt revealed that germination and seedling establishment of gasa14-1 were poorer than those of Col plants and that the 35S::GASA14 lines were more resistant to ABA and salt. Further analysis showed that overexpression of GASA14 could suppress reactive oxygen species (ROS) accumulation. Taken together, these results demonstrated that GASA14 regulates leaf expansion and abiotic stress resistance by modulating ROS accumulation. Because GASA14 contains both GASA (GA-stimulated in Arabidopsis) and PRP (proline-rich protein) domains, the PRP domain coding sequence was overexpressed in Col plants and it was found that the growth of the transgenic plants and the responses to ABA and salt were not altered. These results thus suggest that the GASA domain is necessary for the functions of GASA14.

  10. Lack of reactive oxygen species deteriorates blood pressure regulation in acute stress.

    PubMed

    Bernátová, I; Bališ, P; Goga, R; Behuliak, M; Zicha, J; Sekaj, I

    2016-10-24

    This study investigated the contribution of reactive oxygen species (ROS) to blood pressure regulation in conscious adult male Wistar rats exposed to acute stress. Role of ROS was investigated in rats with temporally impaired principal blood pressure regulation systems using ganglionic blocker pentolinium (P, 5 mg/kg), angiotensin converting enzyme inhibitor captopril (C, 10 mg/kg), nitric oxide synthase inhibitor L-NAME (L, 30 mg/kg) and superoxide dismutase mimeticum tempol (T, 25 mg/kg). Mean arterial pressure (MAP) was measured by the carotid artery catheter and inhibitors were administered intravenously. MAP was disturbed by a 3-s air jet, which increased MAP by 35.2+/-3.0 % vs. basal MAP after the first exposure. Air jet increased MAP in captopril- and tempol-treated rats similarly as observed in saline-treated rats. In pentolinium-treated rats stress significantly decreased MAP vs. pre-stress value. In L-NAME-treated rats stress failed to affect MAP significantly. Treatment of rats with P+L+C resulted in stress-induced MAP decrease by 17.3+/-1.3 % vs. pre-stress value and settling time (20.1+/-4.2 s). In P+L+C+T-treated rats stress led to maximal MAP decrease by 26.4+/-2.2 % (p<0.005 vs. P+L+C) and prolongation of settling time to 32.6+/-3.3 s (p<0.05 vs. P+L+C). Area under the MAP curve was significantly smaller in P+L+C-treated rats compared to P+L+C+T-treated ones (167+/-43 vs. 433+/-69 a.u., p<0.008). In conclusion, in rats with temporally impaired blood pressure regulation, the lack of ROS resulted in greater stress-induced MAP alterations and prolongation of time required to reach new post-stress steady state.

  11. Regulation of Rac1 and Reactive Oxygen Species Production in Response to Infection of Gastrointestinal Epithelia

    PubMed Central

    Ablack, Amber; Hall, Emily H.; Butcher, Lindsay D.; Bhattacharyya, Asima; Eckmann, Lars; Harris, Paul R.; Das, Soumita; Ernst, Peter B.; Crowe, Sheila E.

    2016-01-01

    Generation of reactive oxygen species (ROS) during infection is an immediate host defense leading to microbial killing. APE1 is a multifunctional protein induced by ROS and after induction, protects against ROS-mediated DNA damage. Rac1 and NAPDH oxidase (Nox1) are important contributors of ROS generation following infection and associated with gastrointestinal epithelial injury. The purpose of this study was to determine if APE1 regulates the function of Rac1 and Nox1 during oxidative stress. Gastric or colonic epithelial cells (wild-type or with suppressed APE1) were infected with Helicobacter pylori or Salmonella enterica and assessed for Rac1 and NADPH oxidase-dependent superoxide production. Rac1 and APE1 interactions were measured by co-immunoprecipitation, confocal microscopy and proximity ligation assay (PLA) in cell lines or in biopsy specimens. Significantly greater levels of ROS were produced by APE1-deficient human gastric and colonic cell lines and primary gastric epithelial cells compared to control cells after infection with either gastric or enteric pathogens. H. pylori activated Rac1 and Nox1 in all cell types, but activation was higher in APE1 suppressed cells. APE1 overexpression decreased H. pylori-induced ROS generation, Rac1 activation, and Nox1 expression. We determined that the effects of APE1 were mediated through its N-terminal lysine residues interacting with Rac1, leading to inhibition of Nox1 expression and ROS generation. APE1 is a negative regulator of oxidative stress in the gastrointestinal epithelium during bacterial infection by modulating Rac1 and Nox1. Our results implicate APE1 in novel molecular interactions that regulate early stress responses elicited by microbial infections. PMID:26761793

  12. 75 FR 30812 - Frequency Regulation Compensation in the Organized Wholesale Power Markets; Further Notice...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-02

    ... Energy Regulatory Commission Frequency Regulation Compensation in the Organized Wholesale Power Markets... of Proposed Rulemaking on Frequency Regulation Compensation in the Organized Wholesale Power Markets, as previously announced.\\1\\ \\1\\ Notice of Technical Conference re Frequency Compensation in...

  13. 75 FR 31430 - Frequency Regulation Compensation in the Organized Wholesale Power Markets; Notice Establishing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-03

    ... Energy Regulatory Commission Frequency Regulation Compensation in the Organized Wholesale Power Markets... technical conference regarding frequency regulation in the organized wholesale power markets, as previously announced.\\1\\ \\1\\ Notice of Technical Conference re Frequency Compensation in the Organized Wholesale...

  14. Multi-Objective Advanced Inverter Controls to Dispatch the Real and Reactive Power of Many Distributed PV Systems.

    SciTech Connect

    Reno, Matthew J.; Lave, Matthew Samuel; Broderick, Robert Joseph; Seuss, John; Grijalva, Santiago

    2016-01-01

    The research presented in this report compares several real - time control strategies for the power output of a large number of PV distributed throughout a large distribution feeder circuit. Both real and reactive power controls are considered with the goal of minimizing network over - voltage violations caused by large amounts of PV generation. Several control strategies are considered under various assumptions regarding the existence and latency of a communication network. The control parameters are adjusted to maximize the effectiveness of each control. The controls are then compared based on their ability to achieve multiple objectiv es. These objectives include minimizing the total number of voltage violations , minimizing the total amount of PV energy curtailed or reactive power generated, and maximizing the fairness of any control action among all PV systems . The controls are simulat ed on the OpenDSS platform using time series load and spatially - distributed irradiance data.

  15. Role of NADPH oxidases and reactive oxygen species in regulation of bone turnover and the skeletal toxicity of alcohol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recent studies with genetically modified mice and dietary antioxidants have suggested an important role for superoxide derived from NADPH oxidase (NOX) enzymes and other reactive oxygen species (ROS) such as hydrogen peroxide in regulation of normal bone turnover during development and also in the r...

  16. CFD-based turbulent reactive flow simulations of power plant plumes

    NASA Astrophysics Data System (ADS)

    Yang, Bo; Zhang, K. Max

    2017-02-01

    trajectory with that estimated using a semi-empirical equation and Cumberland-specific parameters indicated that RANS-VS can reasonably predict plume evolution in the JDR as well. Our study suggested that properly configured CFD simulations (e.g., turbulence model, source representation and mesh sensitivity) were able to capture the evolution of chemical reactive plumes from power plants in high accuracy, however, with high computational cost and thus limited applicable spatial range.

  17. Digital regulation of a phase controlled power converter

    SciTech Connect

    Schultheiss, C.; Haque, T.

    1995-12-01

    The Relativistic Heavy Ion Collider, now in construction at Brookhaven National Laboratory, will use phase controlled power converters for the main dipole and quadrupole magnet strings. The rectifiers in these power supplies will be controlled by a digital regulator based on the TI 320C30 Digital Signal Processor (DSP). The DSP implements the current loop, the voltage loop, and a system to actively reduce the sub-harmonic ripple components. Digital firing circuits consisting of a phase locked lop and counters are used to fire the SCRs. Corrections for the sub-harmonic reduction are calculated by the DSP and stored in registers in the firing circuit. These corrections are added in hardware, to the over-all firing count provided by the DSP. the resultant count is compared to a reference counter to fire the SCRs. This combination of a digital control system and the digital firing circuits allows the correction of the sub-harmonics in a real-time sense. A prototype of the regulator has been constructed, and the preliminary testing indicates a sub-harmonic reduction of 60 dB.

  18. Antioxidant Enzymes Regulate Reactive Oxygen Species during Pod Elongation in Pisum sativum and Brassica chinensis

    PubMed Central

    Liu, Nan; Lin, Zhifang; Guan, Lanlan; Gaughan, Gerald; Lin, Guizhu

    2014-01-01

    Previous research has focused on the involvement of reactive oxygen species (ROS) in cell wall loosening and cell extension in plant vegetative growth, but few studies have investigated ROS functions specifically in plant reproductive organs. In this study, ROS levels and antioxidant enzyme activities were assessed in Pisum sativum and Brassica chinensis pods at five developmental stages. In juvenile pods, the high levels of O2.− and.OH indicates that they had functions in cell wall loosening and cell elongation. In later developmental stages, high levels of.OH were also related to increases in cell wall thickness in lignified tissues. Throughout pod development, most of the O2.− was detected on plasma membranes of parenchyma cells and outer epidermis cells of the mesocarp, while most of the H2O2 was detected on plasma membranes of most cells throughout the mesocarp. This suggests that these sites are presumably the locations of ROS generation. The antioxidant enzymes superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) apparently contributed to ROS accumulation in pod wall tissues. Furthermore, specifically SOD and POD were found to be associated with pod growth through the regulation of ROS generation and transformation. Throughout pod development, O2.− decreases were associated with increased SOD activity, while changes in H2O2 accumulation were associated with changes in CAT and POD activities. Additionally, high POD activity may contribute to the generation of.OH in the early development of pods. It is concluded that the ROS are produced in different sites of plasma membranes with the regulation of antioxidant enzymes, and that substantial ROS generation and accumulation are evident in cell elongation and cell wall loosening in pod wall cells. PMID:24503564

  19. Regulation of Reactive Oxygen Species and the Antioxidant Protein DJ-1 in Mastocytosis

    PubMed Central

    Kim, Do-Kyun; Beaven, Michael A.; Kulinski, Joseph M.; Desai, Avanti; Bandara, Geethani; Bai, Yun; Prussin, Calman; Schwartz, Lawrence B.; Komarow, Hirsh

    2016-01-01

    Neoplastic accumulation of mast cells in systemic mastocytosis (SM) associates with activating mutations in the receptor tyrosine kinase KIT. Constitutive activation of tyrosine kinase oncogenes has been linked to imbalances in oxidant/antioxidant mechanisms in other myeloproliferative disorders. However, the impact of KIT mutations on the redox status in SM and the potential therapeutic implications are not well understood. Here, we examined the regulation of reactive oxygen species (ROS) and of the antioxidant protein DJ-1 (PARK-7), which increases with cancer progression and acts to lessen oxidative damage to malignant cells, in relationship with SM severity. ROS levels were increased in both indolent (ISM) and aggressive variants of the disease (ASM). However, while DJ-1 levels were reduced in ISM with lower mast cell burden, they rose in ISM with higher mast cell burden and were significantly elevated in patients with ASM. Studies on mast cell lines revealed that activating KIT mutations induced constant ROS production and consequent DJ-1 oxidation and degradation that could explain the reduced levels of DJ-1 in the ISM population, while IL-6, a cytokine that increases with disease severity, caused a counteracting transcriptional induction of DJ-1 which would protect malignant mast cells from oxidative damage. A mouse model of mastocytosis recapitulated the biphasic changes in DJ-1 and the escalating IL-6, ROS and DJ-1 levels as mast cells accumulate, findings which were reversed with anti-IL-6 receptor blocking antibody. Our findings provide evidence of increased ROS and a biphasic regulation of the antioxidant DJ-1 in variants of SM and implicate IL-6 in DJ-1 induction and expansion of mast cells with KIT mutations. We propose consideration of IL-6 blockade as a potential adjunctive therapy in the treatment of patients with advanced mastocytosis, as it would reduce DJ-1 levels making mutation-positive mast cells vulnerable to oxidative damage. PMID:27611333

  20. The Promotion of Erythropoiesis via the Regulation of Reactive Oxygen Species by Lactic Acid

    PubMed Central

    Luo, Shun-Tao; Zhang, Dong-Mei; Qin, Qing; Lu, Lian; Luo, Min; Guo, Fu-Chun; Shi, Hua-Shan; Jiang, Li; Shao, Bin; Li, Meng; Yang, Han-Shuo; Wei, Yu-Quan

    2017-01-01

    The simultaneous increases in blood lactic acid and erythrocytes after intense exercise could suggest a link between lactate and the erythropoiesis. However, the effects of lactic acid on erythropoiesis remain to be elucidated. Here, we utilized a mouse model to determine the role of lactic acid in this process in parallel with studies using leukaemic K562 cells. Treatment of K562 cells in vitro with lactic acid increased the mRNA and protein expression of haemoglobin genes and the frequency of GPA+ cells. Also, increases in haematocrit and CD71−/Ter119+ erythroid cells were observed in lactic acid-treated mice, which showed a physiological increase in blood lactate. Mouse bone marrow CD34+/CD117− cells showed an increase in erythroid burst-forming units after stimulation with lactic acid in vitro. Furthermore, lactic acid increased the intracellular reactive oxygen species (ROS) content in bone marrow and in K562 cells. Erythroid differentiation induced in Haematopoietic Stem Cells (HSCs) and K562 cells by lactic acid was abolished by reducing ROS levels with SOD or 2-mercaptoethanol, which suggests that ROS is a critical regulator of this process. These findings provide a better understanding of the role of lactic acid in cellular metabolism and physiological functions. PMID:28165036

  1. Peroxiredoxin-3 Is Involved in Bactericidal Activity through the Regulation of Mitochondrial Reactive Oxygen Species

    PubMed Central

    Lee, Sena; Wi, Sae Mi; Min, Yoon

    2016-01-01

    Peroxiredoxin-3 (Prdx3) is a mitochondrial protein of the thioredoxin family of antioxidant peroxidases and is the principal peroxidase responsible for metabolizing mitochondrial hydrogen peroxide. Recent reports have shown that mitochondrial reactive oxygen species (mROS) contribute to macrophage-mediated bactericidal activity in response to Toll-like receptors. Herein, we investigated the functional effect of Prdx3 in bactericidal activity. The mitochondrial localization of Prdx3 in HEK293T cells was confirmed by cell fractionation and confocal microscopy analyses. To investigate the functional role of Prdx3 in bactericidal activity, Prdx3-knockdown (Prdx3KD) THP-1 cells were generated. The mROS levels in Prdx3KD THP-1 cells were significantly higher than those in control THP-1 cells. Moreover, the mROS levels were markedly increased in response to lipopolysaccharide. Notably, the Salmonella enterica serovar Typhimurium infection assay revealed that the Prdx3KD THP-1 cells were significantly resistant to S. Typhimurium infection, as compared with control THP-1 cells. Taken together, these results indicate that Prdx3 is functionally important in bactericidal activity through the regulation of mROS. PMID:28035213

  2. The Promotion of Erythropoiesis via the Regulation of Reactive Oxygen Species by Lactic Acid.

    PubMed

    Luo, Shun-Tao; Zhang, Dong-Mei; Qin, Qing; Lu, Lian; Luo, Min; Guo, Fu-Chun; Shi, Hua-Shan; Jiang, Li; Shao, Bin; Li, Meng; Yang, Han-Shuo; Wei, Yu-Quan

    2017-02-06

    The simultaneous increases in blood lactic acid and erythrocytes after intense exercise could suggest a link between lactate and the erythropoiesis. However, the effects of lactic acid on erythropoiesis remain to be elucidated. Here, we utilized a mouse model to determine the role of lactic acid in this process in parallel with studies using leukaemic K562 cells. Treatment of K562 cells in vitro with lactic acid increased the mRNA and protein expression of haemoglobin genes and the frequency of GPA(+) cells. Also, increases in haematocrit and CD71(-)/Ter119(+) erythroid cells were observed in lactic acid-treated mice, which showed a physiological increase in blood lactate. Mouse bone marrow CD34(+)/CD117(-) cells showed an increase in erythroid burst-forming units after stimulation with lactic acid in vitro. Furthermore, lactic acid increased the intracellular reactive oxygen species (ROS) content in bone marrow and in K562 cells. Erythroid differentiation induced in Haematopoietic Stem Cells (HSCs) and K562 cells by lactic acid was abolished by reducing ROS levels with SOD or 2-mercaptoethanol, which suggests that ROS is a critical regulator of this process. These findings provide a better understanding of the role of lactic acid in cellular metabolism and physiological functions.

  3. Reactive Oxygen Species Regulate T Cell Immune Response in the Tumor Microenvironment

    PubMed Central

    Chen, Xinfeng; Song, Mengjia

    2016-01-01

    Reactive oxygen species (ROS) produced by cellular metabolism play an important role as signaling messengers in immune system. ROS elevated in the tumor microenvironment are associated with tumor-induced immunosuppression. T cell-based therapy has been recently approved to be effective for cancer treatment. However, T cells often become dysfunctional after reaching the tumor site. It has been reported that ROS participate extensively in T cells activation, apoptosis, and hyporesponsiveness. The sensitivity of T cells to ROS varies among different subsets. ROS can be regulated by cytokines, amino acid metabolism, and enzymatic activity. Immunosuppressive cells accumulate in the tumor microenvironment and induce apoptosis and functional suppression of T cells by producing ROS. Thus, modulating the level of ROS may be important to prolong survival of T cells and enhance their antitumor function. Combining T cell-based therapy with antioxidant treatment such as administration of ROS scavenger should be considered as a promising strategy in cancer treatment, aiming to improve antitumor T cells immunity. PMID:27547291

  4. The early embryo response to intracellular reactive oxygen species is developmentally regulated.

    PubMed

    Bain, Nathan T; Madan, Pavneesh; Betts, Dean H

    2011-01-01

    In vitro embryo production (IVP) suffers from excessive developmental failure. Its inefficiency is linked, in part, to reactive oxygen species (ROS) brought on by high ex vivo oxygen (O(2)) tensions. To further delineate the effects of ROS on IVP, the intracellular ROS levels of early bovine embryos were modulated by: (1) varying O(2) tension; (2) exogenous H(2)O(2) treatment; and (3) antioxidant supplementation. Although O(2) tension did not significantly affect blastocyst frequencies (P>0.05), 20% O(2) accelerated the rate of first cleavage division and significantly decreased and increased the proportion of permanently arrested 2- to 4-cell embryos and apoptotic 9- to 16-cell embryos, respectively, compared with embryos cultured in 5% O(2) tension. Treatment with H(2)O(2), when applied separately to oocytes, zygotes, 2- to 4-cell embryos or 9- to 16-cell embryos, resulted in a significant (P<0.05) dose-dependent decrease in blastocyst development in conjunction with a corresponding increase in the induction of either permanent embryo arrest or apoptosis in a stage-dependent manner. Polyethylene glycol-catalase supplementation reduced ROS-induced embryo arrest and/or death, resulting in a significant (P<0.05) increase in blastocyst frequencies under high O(2) culture conditions. Together, these results indicate that intracellular ROS may be signalling molecules that, outside an optimal range, result in various developmentally regulated modes of embryo demise.

  5. Regulation of insulin secretion and reactive oxygen species production by free fatty acids in pancreatic islets.

    PubMed

    Graciano, Maria Fernanda Rodrigues; Valle, Maíra M R; Kowluru, Anjan; Curi, Rui; Carpinelli, Angelo R

    2011-01-01

    Free fatty acids regulate insulin secretion through metabolic and intracellular signaling mechanisms such as induction of malonyl-CoA/long-chain CoA pathway, production of lipids, GPRs (G protein-coupled receptors) activation and the modulation of calcium currents. Fatty acids (FA) are also important inducers of ROS (reactive oxygen species) production in β-cells. Production of ROS for short periods is associated with an increase in GSIS (glucose-stimulated insulin secretion), but excessive or sustained production of ROS is negatively correlated with the insulin secretory process. Several mechanisms for FA modulation of ROS production by pancreatic β-cells have been proposed, such as the control of mitochondrial complexes and electron transport, induction of uncoupling proteins, NADPH oxidase activation, interaction with the renin-angiotensin system, and modulation of the antioxidant defense system. The major sites of superoxide production within mitochondria derive from complexes I and III. The amphiphilic nature of FA favors their incorporation into mitochondrial membranes, altering the membrane fluidity and facilitating the electron leak. The extra-mitochondrial ROS production induced by FA through the NADPH oxidase complex is also an important source of these species in β-cells.

  6. Electric utility power plant choice under investment regulation

    SciTech Connect

    Rothwell, G.S.

    1985-01-01

    Economists have examined electric utility behavior under an allowed rate of return (ARoR), but little attention has been given to the regulation of generation technology choice. Two financial methods for regulating this investment decision are Allowance for Funds Used During Construction (AFUDC) and Construction Work in Progress (CWIP). The switch from AFUDC to CWIP by federal and state commissions has sparked a national debate. One issue addressed in this study is whether AFUDC or CWIP influenced technology choice. The first chapter reviews policy and compares the present value of returns to the firm under AFUDC with returns under CWIP. Chapter 2 discusses previous studied of electric utility behavior. In the third chapter, a general model is developed in which profit and revenue maximization, and cost minimization, are nested. It incorporates cost uncertainty, as well as AFUDC and CWIP. Chapter 4 estimates cost functions for coal and nuclear capacity with data on 350 units completed between 1965 and 1980. These estimates are used to forecast firm expectations on the mean and variance of power plant costs. Results suggest that while rate-of-return and investment regulation may not have had a great influence on plant choice, policies that change perceived cost uncertainties will have a significant impact on firm behavior.

  7. Satellite Power System (SPS). State and local regulations as applied to satellite power system microwave receiving antenna facilities

    NASA Technical Reports Server (NTRS)

    Kotin, A. D.

    1978-01-01

    State and local regulation of power plant construction and operation of solar power satellite (SPS) receiving stations is presented. Each receiving antenna station occupies a land area 100-200 km square, receives microwave transmissions from the solar power satellite, and converts them into electricity for transmission to the power grid. The long lead time associated with the SPS and the changing status of state and local regulation dictated emphasis on: generic classification of the types of regulation, and identification of regulatory vectors which affect rectenna facilities.

  8. Compatibility of Space Nuclear Power Plant Materials in an Inert He/Xe Working Gas Containing Reactive Impurities

    SciTech Connect

    MM Hall

    2006-01-31

    A major materials selection and qualification issue identified in the Space Materials Plan is the potential for creating materials compatibility problems by combining dissimilar reactor core, Brayton Unit and other power conversion plant materials in a recirculating, inert He/Xe gas loop containing reactive impurity gases. Reported here are results of equilibrium thermochemical analyses that address the compatibility of space nuclear power plant (SNPP) materials in high temperature impure He gas environments. These studies provide early information regarding the constraints that exist for SNPP materials selection and provide guidance for establishing test objectives and environments for SNPP materials qualification testing.

  9. 77 FR 35671 - Conformed Power Marketing Criteria or Regulations for the Boulder Canyon Project

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-14

    ... Area Power Administration Conformed Power Marketing Criteria or Regulations for the Boulder Canyon Project AGENCY: Western Area Power Administration, DOE. ACTION: Conformance of power marketing criteria in... (Western), a Federal power marketing agency of the Department of Energy (DOE), is modifying Part C of...

  10. Vanadium compounds discriminate hepatoma and normal hepatic cells by differential regulation of reactive oxygen species.

    PubMed

    Wang, Qin; Liu, Tong-Tong; Fu, Ying; Wang, Kui; Yang, Xiao-Gai

    2010-09-01

    Our previous study indicated that vanadium compounds can block cell cycle progression at the G1/S phase in human hepatoma HepG2 cells via a highly activated extracellular signal-regulated protein kinase (ERK) signal. To explore their differential action on normal cells, we investigated the response of an immortalized hepatic cell line, L02 cells. The results demonstrated that a higher concentration of vanadium compounds was needed to inhibit L02 proliferation, which was associated with S and G2/M cell cycle arrest. In addition, in contrast to insignificant reactive oxygen species (ROS) generation in HepG2 cells, all of the vanadium compounds resulted significant increases in both O2.- and H2O2 levels in L02 cells. At the same time, ERK and c-Jun N-terminal kinase (JNK) as well as cell division control protein 2 homolog (Cdc2) were found to be highly phosphorylated, which could be counteracted with the antioxidant N-acetylcysteine (NAC). The current study also demonstrated that both the ERK and the JNK pathways contributed to the cell cycle arrest induced by vanadium compounds in L02 cells. More importantly, it was found that although NAC can ameliorate the cytotoxicity of vanadium compounds in L02 cells, it did not decrease their cytotoxicity in HepG2 cells. It thus shed light on the potential therapeutic applications of vanadium compounds with antioxidants as synergistic agents to reduce their toxicities in human normal cells without affecting their antitumor activities in cancer cells.

  11. Photovoltaic-powered regulated cathodic-protection system

    NASA Astrophysics Data System (ADS)

    Anis, Wagdy R.; Alfons, Hany A.

    The objective of a cathodic protection system is to protect metallic structures against corrosion. To achieve this, a sacrificial anode is connected to the protected structure (which acts as a cathode) through a d.c. power supply. To stop the corrosion, the protected structure requires a constant current. The current is determined by the metal and area of the structure, as well as the surrounding medium. The major difficulty in achieving a constant current is the variation in the resistivity of the surrounding medium that is caused by changes in the climatic conditions. Conventional cathodic-protection systems resolve this problem by manual adjustment of the d.c. voltage periodically to obtain a constant current. Such adjustment depends on the experience of the technician and the accuracy of the measuring equipment. Moreover if the interval between successive adjustments is relative long, the corrosion could become excessive. To overcome such difficulties, an automatically regulated system has been developed. The proposed system senses variations is the resistivity of the surrounding medium and adjusts the d.c. voltage accordingly so that the current is kept constant at the required level. The design of a solar photovoltaic system to supply the required d.c. power is discussed in this communication.

  12. Voltage control for a wind power plant based on the available reactive current of a DFIG and its impacts on the point of interconnection

    DOE PAGES

    Usman, Yasir; Kim, Jinho; Muljadi, Eduard; ...

    2016-01-01

    Wake effects cause wind turbine generators (WTGs) within a wind power plant (WPP) to produce different levels of active power and subsequent reactive power capabilities. Further, the impedance between a WTG and the point of interconnection (POI)-which depends on the distance between them-impacts the WPP's reactive power injection capability at the POI. This paper proposes a voltage control scheme for a WPP based on the available reactive current of the doubly-fed induction generators (DFIGs) and its impacts on the POI to improve the reactive power injection capability of the WPP. In this paper, a design strategy for modifying the gainmore » of DFIG controller is suggested and the comprehensive properties of these control gains are investigated. In the proposed scheme, the WPP controller, which operates in a voltage control mode, sends the command signal to the DFIGs based on the voltage difference at the POI. The DFIG controllers, which operate in a voltage control mode, employ a proportional controller with a limiter. The gain of the proportional controller is adjusted depending on the available reactive current of the DFIG and the series impedance between the DFIG and the POI. The performance of the proposed scheme is validated for various disturbances such as a reactive load connection and grid fault using an EMTP-RV simulator. Furthermore, simulation results demonstrate that the proposed scheme promptly recovers the POI voltage by injecting more reactive power after a disturbance than the conventional scheme.« less

  13. Voltage control for a wind power plant based on the available reactive current of a DFIG and its impacts on the point of interconnection

    SciTech Connect

    Usman, Yasir; Kim, Jinho; Muljadi, Eduard; Kang, Yong Cheol

    2016-01-01

    Wake effects cause wind turbine generators (WTGs) within a wind power plant (WPP) to produce different levels of active power and subsequent reactive power capabilities. Further, the impedance between a WTG and the point of interconnection (POI)-which depends on the distance between them-impacts the WPP's reactive power injection capability at the POI. This paper proposes a voltage control scheme for a WPP based on the available reactive current of the doubly-fed induction generators (DFIGs) and its impacts on the POI to improve the reactive power injection capability of the WPP. In this paper, a design strategy for modifying the gain of DFIG controller is suggested and the comprehensive properties of these control gains are investigated. In the proposed scheme, the WPP controller, which operates in a voltage control mode, sends the command signal to the DFIGs based on the voltage difference at the POI. The DFIG controllers, which operate in a voltage control mode, employ a proportional controller with a limiter. The gain of the proportional controller is adjusted depending on the available reactive current of the DFIG and the series impedance between the DFIG and the POI. The performance of the proposed scheme is validated for various disturbances such as a reactive load connection and grid fault using an EMTP-RV simulator. Furthermore, simulation results demonstrate that the proposed scheme promptly recovers the POI voltage by injecting more reactive power after a disturbance than the conventional scheme.

  14. Voltage regulator dissipates minimal power and functions as a voltage divider

    NASA Technical Reports Server (NTRS)

    Hester, H. B.

    1971-01-01

    Regulator requires minimum amount of power for voltage division and it is not required continuously. The only power loss, except for regulating purposes, is that needed to provide for imbalances in load current requirements. For balanced loads, only leakage current flows through regulating transistors.

  15. Influence of nitrogen admixture to argon on the ion energy distribution in reactive high power pulsed magnetron sputtering of chromium

    NASA Astrophysics Data System (ADS)

    Breilmann, W.; Maszl, C.; Hecimovic, A.; von Keudell, A.

    2017-04-01

    Reactive high power impulse magnetron sputtering (HiPIMS) of metals is of paramount importance for the deposition of various oxides, nitrides and carbides. The addition of a reactive gas such as nitrogen to an argon HiPIMS plasma with a metal target allows the formation of the corresponding metal nitride on the substrate. The addition of a reactive gas introduces new dynamics into the plasma process, such as hysteresis, target poisoning and the rarefaction of two different plasma gases. We investigate the dynamics for the deposition of chromium nitride by a reactive HiPIMS plasma using energy- and time-resolved ion mass spectrometry, fast camera measurements and temporal and spatially resolved optical emission spectroscopy. It is shown that the addition of nitrogen to the argon plasma gas significantly changes the appearance of the localized ionization zones, the so-called spokes, in HiPIMS plasmas. In addition, a very strong modulation of the metal ion flux within each HiPIMS pulse is observed, with the metal ion flux being strongly suppressed and the nitrogen molecular ion flux being strongly enhanced in the high current phase of the pulse. This behavior is explained by a stronger return effect of the sputtered metal ions in the dense plasma above the racetrack. This is best observed in a pure nitrogen plasma, because the ionization zones are mostly confined, implying a very high local plasma density and consequently also an efficient scattering process.

  16. Observation of a periodic runaway in the reactive Ar/O{sub 2} high power impulse magnetron sputtering discharge

    SciTech Connect

    Shayestehaminzadeh, Seyedmohammad E-mail: shayesteh@mch.rwth-aachen.de; Arnalds, Unnar B.; Magnusson, Rögnvaldur L.; Olafsson, Sveinn

    2015-11-15

    This paper reports the observation of a periodic runaway of plasma to a higher density for the reactive discharge of the target material (Ti) with moderate sputter yield. Variable emission of secondary electrons, for the alternating transition of the target from metal mode to oxide mode, is understood to be the main reason for the runaway occurring periodically. Increasing the pulsing frequency can bring the target back to a metal (or suboxide) mode, and eliminate the periodic transition of the target. Therefore, a pulsing frequency interval is defined for the reactive Ar/O{sub 2} discharge in order to sustain the plasma in a runaway-free mode without exceeding the maximum power that the magnetron can tolerate.

  17. Examining the Variability of Wind Power Output in the Regulation Time Frame: Preprint

    SciTech Connect

    Hodge, B. M.; Shedd, S.; Florita, A.

    2012-08-01

    This work examines the distribution of changes in wind power for different time scales in the regulation time frame as well as the correlation of changes in power output for individual wind turbines in a wind plant.

  18. The shunt-LDO regulator to power the upgraded ATLAS pixel detector

    NASA Astrophysics Data System (ADS)

    Gonella, L.; Barbero, M.; Hügging, F.; Krüger, H.; Wermes, N.

    2012-01-01

    The shunt-LDO regulator is a new regulator concept which combines a shunt and a Low Drop-Out (LDO) regulator. Designed as an improved shunt regulator to match the needs of serially powered detector systems, it can also be used as a pure LDO regulator for general application in powering schemes requiring linear regulation. The flexibility of the design makes the shunt-LDO regulator a good candidate for use in the powering schemes envisaged for the upgrades of the ATLAS pixel detector. Two shunt-LDO regulators integrated in the prototype of the next ATLAS pixel front-end chip, the FE-I4A, are used to demonstrate the feasibility of the proposed powering solutions.

  19. 75 FR 23759 - Frequency Regulation Compensation in the Organized Wholesale Power Markets; Notice of Technical...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-04

    ... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Frequency Regulation Compensation in the Organized Wholesale Power... technical conference to elicit input on issues pertaining to Frequency Regulation Compensation in the...

  20. Review of nuclear power plant offsite power source reliability and related recommended changes to the NRC rules and regulations

    SciTech Connect

    Battle, R.E.; Clark, F.H.; Reddoch, T.W.

    1980-05-01

    The NRC has stated its concern about the reliability of the offsite power system as the preferred emergency source and about the possible damage to a pressurized water reactor (PWR) that could result from a rapid decay of power grid frequency. ORNL contracted with NRC to provide technical assistance to establish criteria that can be used to evaluate the offsite power system for the licensing of a nuclear power plant. The results of many of the studies for this contract are recommendations to assess and control the power grid during operation. This is because most of the NRC regulations pertaining to the offsite power system are related to the design of the power grid, and we believe that additional emphasis on monitoring the power grid operation will improve the reliability of the nuclear plant offsite power supply. 46 refs., 10 figs.

  1. NRROS Negatively Regulates Osteoclast Differentiation by Inhibiting RANKL-Mediated NF-κB and Reactive Oxygen Species Pathways

    PubMed Central

    Kim, Jung Ha; Kim, Kabsun; Kim, Inyoung; Seong, Semun; Kim, Nacksung

    2015-01-01

    Negative regulator of reactive oxygen species (NRROS) is known to repress ROS generation in phagocytes. In this study, we examined the roles of NRROS in both osteoclasts and osteoblasts. Our results demonstrate that NRROS negatively regulates the differentiation of osteoclasts, but not osteoblasts. Further, overexpression of NRROS in osteoclast precursor cells attenuates RANKL-induced osteoclast differentiation. Conversely, osteoclast differentiation is enhanced upon siRNA-mediated knockdown of NRROS. Additionally, NRROS attenuates RANKL-induced NF-κB activation, as well as degradation of the NOX1 and NOX2 proteins, which are required for ROS generation. Based on our observations, we present NRROS as a novel negative regulator of RANKL-induced osteoclastogenesis. PMID:26442864

  2. Effects of thyroid hormone on HSV-1 gene regulation: implications in the control of viral latency and reactivation

    PubMed Central

    2011-01-01

    Thyroid hormone (TH) is involved in many biological functions such as animal development, cell differentiation, etc. Variation and/or disruption of plasma TH level often led to abnormalities and physiological disorders. TH exerts the effects through its nuclear receptors (TR). Literature showed that procedures resulted in TH alteration also linked to reactivation of several viruses including Herpes Simplex Virus Type -1 (HSV-1). Bioinformatic analyses revealed a number of putative TH responsive elements (TRE) located in the critical regulatory regions of HSV-1 genes such as thymidine kinase (TK), latency associated transcript (LAT), etc. Studies using neuronal cell lines have provided evidences demonstrating that liganded TR regulated viral gene expression via chromatin modification and controlled viral replication. The removal of TH reversed the inhibition and induced the viral replication previously blocked by TH. These results suggest that TH may have implication to participate in the control of reactivation during HSV-1 latency. PMID:21756309

  3. An Aircraft Electric Power Testbed for Validating Automatically Synthesized Reactive Control Protocols

    DTIC Science & Technology

    2013-01-01

    we describe our recently developed simulation models and a hardware testbed for validating reactive controllers synthesized using TuLiP [1], a...temporal logic planning toolbox, in order to investigate the validity of the assumptions made in controller synthesis. TuLiP is a collection of Python... TuLiP can be used to synthesize logic so that the satisfaction of certain safety requirements is guaranteed. The synthesized logic enables the contac

  4. Profiles of Disruptive Behavior across Early Childhood: Contributions of Frustration Reactivity, Physiological Regulation, and Maternal Behavior

    ERIC Educational Resources Information Center

    Degnan, Kathryn A.; Calkins, Susan D.; Keane, Susan P.; Hill-Soderlund, Ashley L.

    2008-01-01

    Disruptive behavior, including aggression, defiance, and temper tantrums, typically peaks in early toddlerhood and decreases by school entry; however, some children do not show this normative decline. The current study examined disruptive behavior in 318 boys and girls at 2, 4, and 5 years of age and frustration reactivity, physiological…

  5. An ionization region model of the reactive Ar/O2 high power impulse magnetron sputtering discharge

    NASA Astrophysics Data System (ADS)

    Gudmundsson, Jon Tomas; Lundin, Daniel; Brenning, Nils; Raadu, Michel A.; Huo, Chunqing; Minea, Tiberiu

    2016-09-01

    A reactive ionization region model (R-IRM) is developed to describe the reactive Ar/O2 high power impulse magnetron sputtering (HiPIMS) discharge with titanium target. We compare the discharge properties when the discharge is operated in the two well established operating modes, the metal mode and the poisoned mode. Experimentally, it is found that in the metal mode the discharge current waveform displays a typical non-reactive evolution, while in the poisoned mode the discharge current waveform becomes distinctly triangular and the current increases significantly. Using the R-IRM we find that when the discharge is operated in the metal mode Ar+ and Ti+-ions contribute most significantly (roughly equal amounts) to the discharge current while in the poisoned mode the Ar+-ions contribute most significantly to the discharge current while the contribution of O+-ions and secondary electron emission is much smaller. Furthermore, we find that recycling of ionized atoms coming from the target are required for the current generation in both modes of operation. In the metal mode self-sputter recycling dominates and in the poisoned mode working gas recycling dominates, and it is concluded that the dominating type of recycling determines the discharge current waveform.

  6. Role of Organic Coatings in Regulating N2O5 Reactive Uptake to Sea Spray Aerosol.

    PubMed

    Ryder, Olivia S; Campbell, Nicole R; Morris, Holly; Forestieri, Sara; Ruppel, Matthew J; Cappa, Christopher; Tivanski, Alexei; Prather, Kimberly; Bertram, Timothy H

    2015-12-03

    Previous laboratory measurements and field observations have suggested that the reactive uptake of N2O5 to sea spray aerosol particles is a complex function of particle chemical composition and phase, where surface active organics can suppress the reactive uptake by up to a factor of 60. To date, there are no direct studies of the reactive uptake of N2O5 to nascent sea spray aerosol that permit assessment of the role that organic molecules present in sea spray aerosol (SSA) may play in suppressing or enhancing N2O5 uptake kinetics. In this study, SSA was generated from ambient seawater and artificial seawater matrices using a Marine Aerosol Reference Tank (MART), capable of producing nascent SSA representative of ambient conditions. The reactive uptake coefficient of N2O5 (γ(N2O5)) on nascent SSA was determined using an entrained aerosol flow reactor coupled to a chemical ionization mass spectrometer for measurement of surface area dependent heterogeneous loss rates. Population averaged measurements of γ(N2O5) for SSA generated from salt water sequentially doped with representative organic molecular mimics, or from ambient seawater, do not deviate statistically from that observed for sodium chloride (γ(N2O5)NaCl = 0.01-0.03) for relative humidity (RH) ranging between 50 and 65%. The results are consistent with measurements made under clean marine conditions at the Scripps Institution of Oceanography Pier and those conducted on nascent SSA generated in the marine aerosol reference tank. The results presented here suggest that organic films present on nascent SSA (at RH greater than 50%) likely do not significantly limit N2O5 reactive uptake.

  7. Silicon oxynitride films deposited by reactive high power impulse magnetron sputtering using nitrous oxide as a single-source precursor

    SciTech Connect

    Hänninen, Tuomas Schmidt, Susann; Jensen, Jens; Hultman, Lars; Högberg, Hans

    2015-09-15

    Silicon oxynitride thin films were synthesized by reactive high power impulse magnetron sputtering of silicon in argon/nitrous oxide plasmas. Nitrous oxide was employed as a single-source precursor supplying oxygen and nitrogen for the film growth. The films were characterized by elastic recoil detection analysis, x-ray photoelectron spectroscopy, x-ray diffraction, x-ray reflectivity, scanning electron microscopy, and spectroscopic ellipsometry. Results show that the films are silicon rich, amorphous, and exhibit a random chemical bonding structure. The optical properties with the refractive index and the extinction coefficient correlate with the film elemental composition, showing decreasing values with increasing film oxygen and nitrogen content. The total percentage of oxygen and nitrogen in the films is controlled by adjusting the gas flow ratio in the deposition processes. Furthermore, it is shown that the film oxygen-to-nitrogen ratio can be tailored by the high power impulse magnetron sputtering-specific parameters pulse frequency and energy per pulse.

  8. Effects of anodic potential and chloride ion on overall reactivity in electrochemical reactors designed for solar-powered wastewater treatment.

    PubMed

    Cho, Kangwoo; Qu, Yan; Kwon, Daejung; Zhang, Hao; Cid, Clément A; Aryanfar, Asghar; Hoffmann, Michael R

    2014-02-18

    We have investigated electrochemical treatment of real domestic wastewater coupled with simultaneous production of molecular H2 as useful byproduct. The electrolysis cells employ multilayer semiconductor anodes with electroactive bismuth-doped TiO2 functionalities and stainless steel cathodes. DC-powered laboratory-scale electrolysis experiments were performed under static anodic potentials (+2.2 or +3.0 V NHE) using domestic wastewater samples, with added chloride ion in variable concentrations. Greater than 95% reductions in chemical oxygen demand (COD) and ammonium ion were achieved within 6 h. In addition, we experimentally determined a decreasing overall reactivity of reactive chlorine species toward COD with an increasing chloride ion concentration under chlorine radicals (Cl·, Cl2(-)·) generation at +3.0 V NHE. The current efficiency for COD removal was 12% with the lowest specific energy consumption of 96 kWh kgCOD(-1) at the cell voltage of near 4 V in 50 mM chloride. The current efficiency and energy efficiency for H2 generation were calculated to range from 34 to 84% and 14 to 26%, respectively. The hydrogen comprised 35 to 60% by volume of evolved gases. The efficacy of our electrolysis cell was further demonstrated by a 20 L prototype reactor totally powered by a photovoltaic (PV) panel, which was shown to eliminate COD and total coliform bacteria in less than 4 h of treatment.

  9. Cucurbitacin L 2-O-β-Glucoside Demonstrates Apoptogenesis in Colon Adenocarcinoma Cells (HT-29): Involvement of Reactive Oxygen and Nitrogen Species Regulation

    PubMed Central

    Abdelwahab, Siddig Ibrahim; Hassan, Loiy Elsir Ahmed; Abdul Majid, Amin M. S.; Yagi, Sakina M. Ahmed; Mohan, Syam; Elhassan Taha, Manal Mohamed; Ahmad, Syahida; Chuen, Cheah Shiau; Narrima, Putri; Rais, Mohd Mustafa; Syam, Suvitha; Moharam, Bushra Abdulkarim; Hadi, A. Hamid A.

    2012-01-01

    Emerging evidence suggests that reactive oxygen (ROS) and nitrogen (RNS) species can contribute to diverse signalling pathways of inflammatory and tumour cells. Cucurbitacins are a group of highly oxygenated triterpenes. Many plants used in folk medicine to treat cancer have been found to contain cucurbitacins displaying potentially important anti-inflammatory actions. The current study was designed to investigate the anti-ROS and -RNS effects of cucurbitacin L 2-O-β-glucoside (CLG) and the role of these signaling factors in the apoptogenic effects of CLG on human colon cancer cells (HT-29). This natural cucurbitacin was isolated purely from Citrullus lanatus var. citroides (Cucurbitaceae). The results revealed that CLG was cytotoxic to HT-29. CLG increased significantly (P < 0.05) RNA and protein levels of caspase-3 in HT-29 cells when verified using a colorimetric assay and realtime qPCR, respectively. The results showed that lipopolysaccharide/interferon-gamma (LPS/INF-γ) increased nitrous oxide (NO) production inR AW264.7macrophages, whereas N(G)-nitro-L-argininemethyl ester (L-NAME) and CLG curtailed it. This compound did not reveal any cytotoxicity on RAW264.7 macrophages and human normal liver cells (WRL-68) when tested using the MTT assay. Findings of ferric reducing antioxidant power (FRAP) and oxygen radical absorption capacity (ORAC) assays demonstrate the antioxidant properties of CLG. The apoptogenic property of CLG on HT-29 cells is thus related to inhibition of reactive nitrogen and oxygen reactive species and the triggering of caspase-3-regulated apoptosis. PMID:22685485

  10. Regulation of signal transduction by reactive oxygen species in the cardiovascular system

    PubMed Central

    Brown, David I.; Griendling, Kathy K.

    2015-01-01

    Oxidative stress has long been implicated in cardiovascular disease, but more recently, the role of reactive oxygen species in normal physiological signaling has been elucidated. Signaling pathways modulated by reactive oxygen species (ROS) are complex and compartmentalized, and we are only beginning to identify the molecular modifications of specific targets. Here we review the current literature regarding ROS signaling in the cardiovascular system, focusing on the role of ROS in normal physiology and how dysregulation of signaling circuits contributes to cardiovascular diseases including atherosclerosis, ischemia-reperfusion injury, cardiomyopathy and heart failure. In particular, we consider how ROS modulate signaling pathways related to phenotypic modulation, migration and adhesion, contractility, proliferation and hypertrophy, angiogenesis, endoplasmic reticulum stress, apoptosis and senescence. Understanding the specific targets of ROS may guide the development of the next generation of ROS-modifying therapies to reduce morbidity and mortality associated with oxidative stress. PMID:25634975

  11. Purines regulate adult brain subventricular zone cell functions: contribution of reactive astrocytes.

    PubMed

    Boccazzi, Marta; Rolando, Chiara; Abbracchio, Maria P; Buffo, Annalisa; Ceruti, Stefania

    2014-03-01

    Brain injuries modulate activation of neural stem cells (NSCs) in the adult brain. In pathological conditions, the concentrations of extracellular nucleotides (eNTs) raise several folds, contribute to reactive gliosis, and possibly directly affect subventricular zone (SVZ) cell functioning. Among eNTs and derived metabolites, the P2Y1 receptor agonist ADP strongly promotes astrogliosis and might also influence SVZ progenitor activity. Here, we tested the ability of the stable P2Y1 agonist adenosine 5'-O-(2-thiodiphosphate) (ADPβS) to control adult NSC functions both in vitro and in vivo, with a focus on the possible effects exerted by reactive astrocytes. In the absence of growth factors, ADPβS promoted proliferation and differentiation of SVZ progenitors. Moreover, ADPβS-activated astrocytes markedly changed the pattern of released cytokines and chemokines, and strongly modulated neurosphere-forming capacity of SVZ progenitors. Notably, a significant enhancement in proliferation was observed when SVZ cells, initially grown in the supernatant of astrocytes exposed to ADPβS, were shifted to normal medium. In vivo, ADPβS administration in the lateral ventricle of adult mice by osmotic minipumps caused diffused reactive astrogliosis, and a strong response of SVZ progenitors. Indeed, proliferation of glial fibrillary acidic protein-positive NSCs increased and led to a significant expansion of SVZ transit-amplifying progenitors and neuroblasts. Lineage tracing experiments performed in the GLAST::CreERT2;Rosa-YFP transgenic mice further demonstrated that ADPβS promoted proliferation of glutamate/aspartate transporter-positive progenitors and sustained their progression toward the generation of rapidly dividing progenitors. Altogether, our results show that the purinergic system crucially affects SVZ progenitor activities both directly and through the involvement of reactive astrocytes.

  12. Regulation of erythrocyte lifespan: do reactive oxygen species set the clock?

    PubMed

    Hattangadi, Shilpa M; Lodish, Harvey F

    2007-08-01

    The forkhead box O (Foxo) subfamily of transcription factors regulates expression of genes important for many cellular processes, ranging from initiation of cell cycle arrest and apoptosis to induction of DNA damage repair. Invertebrate Foxo orthologs such as DAF-16 also regulate longevity. Cellular responses inducing resistance to ROS are important for cellular survival and organism lifespan, but until recently, mammalian factors regulating resistance to oxidative stress have not been well characterized. Marinkovic and colleagues demonstrate in this issue of the JCI that Foxo3 is specifically required for induction of proteins that regulate the in vivo oxidative stress response in murine erythrocytes (see the related article beginning on page 2133). Their work offers the interesting hypothesis that in so doing, Foxo3 may regulate the lifespan of red blood cells, and underlies the importance of understanding the direct targets of this transcription factor and its regulation.

  13. 77 FR 21555 - Reactive Power Resources; Supplemental Notice of Technical Conference

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-10

    ... Corporation Yi Zhang, Senior Regional Transmission Engineer, California ISO Eric Laverty, Director of Transmission Access Planning, Midwest ISO Dmitry Kosterev, Electrical Engineer, Bonneville Power Administration... Richard Kowalski, Director--Transmission Strategy and Services, ISO New England Inc. Warren...

  14. 47 CFR 74.780 - Broadcast regulations applicable to translators, low power, and booster stations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., low power, and booster stations. 74.780 Section 74.780 Telecommunication FEDERAL COMMUNICATIONS... PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.780 Broadcast regulations applicable to translators, low power, and booster stations. The following rules are applicable...

  15. 47 CFR 74.780 - Broadcast regulations applicable to translators, low power, and booster stations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ..., low power, and booster stations. 74.780 Section 74.780 Telecommunication FEDERAL COMMUNICATIONS... PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.780 Broadcast regulations applicable to translators, low power, and booster stations. The following rules are applicable...

  16. 47 CFR 74.780 - Broadcast regulations applicable to translators, low power, and booster stations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ..., low power, and booster stations. 74.780 Section 74.780 Telecommunication FEDERAL COMMUNICATIONS... PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.780 Broadcast regulations applicable to translators, low power, and booster stations. The following rules are applicable...

  17. 47 CFR 74.780 - Broadcast regulations applicable to translators, low power, and booster stations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., low power, and booster stations. 74.780 Section 74.780 Telecommunication FEDERAL COMMUNICATIONS... PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.780 Broadcast regulations applicable to translators, low power, and booster stations. The following rules are applicable...

  18. Mothers' Socialization of Emotion Regulation: The Moderating Role of Children's Negative Emotional Reactivity

    ERIC Educational Resources Information Center

    Mirabile, Scott P.; Scaramella, Laura V.; Sohr-Preston, Sara L.; Robison, Sarah D.

    2009-01-01

    During the toddler period, children begin to shift from being primarily dependent on parents to regulate their emotions to managing their emotions independently. The present study considers how children's propensity towards negative emotional arousal interacts with mothers' efforts to socialize emotion regulation. Fifty-five low income mothers and…

  19. Listening to music and physiological and psychological functioning: the mediating role of emotion regulation and stress reactivity.

    PubMed

    Thoma, M V; Scholz, U; Ehlert, U; Nater, U M

    2012-01-01

    Music listening has been suggested to have short-term beneficial effects. The aim of this study was to investigate the association and potential mediating mechanisms between various aspects of habitual music-listening behaviour and physiological and psychological functioning. An internet-based survey was conducted in university students, measuring habitual music-listening behaviour, emotion regulation, stress reactivity, as well as physiological and psychological functioning. A total of 1230 individuals (mean = 24.89 ± 5.34 years, 55.3% women) completed the questionnaire. Quantitative aspects of habitual music-listening behaviour, i.e. average duration of music listening and subjective relevance of music, were not associated with physiological and psychological functioning. In contrast, qualitative aspects, i.e. reasons for listening (especially 'reducing loneliness and aggression', and 'arousing or intensifying specific emotions') were significantly related to physiological and psychological functioning (all p = 0.001). These direct effects were mediated by distress-augmenting emotion regulation and individual stress reactivity. The habitual music-listening behaviour appears to be a multifaceted behaviour that is further influenced by dispositions that are usually not related to music listening. Consequently, habitual music-listening behaviour is not obviously linked to physiological and psychological functioning.

  20. Crosstalk between nitrite, myoglobin and reactive oxygen species to regulate vasodilation under hypoxia.

    PubMed

    Totzeck, Matthias; Hendgen-Cotta, Ulrike B; Kelm, Malte; Rassaf, Tienush

    2014-01-01

    The systemic response to decreasing oxygen levels is hypoxic vasodilation. While this mechanism has been known for more than a century, the underlying cellular events have remained incompletely understood. Nitrite signaling is critically involved in vessel relaxation under hypoxia. This can be attributed to the presence of myoglobin in the vessel wall together with other potential nitrite reductases, which generate nitric oxide, one of the most potent vasodilatory signaling molecules. Questions remain relating to the precise concentration of nitrite and the exact dose-response relations between nitrite and myoglobin under hypoxia. It is furthermore unclear whether regulatory mechanisms exist which balance this interaction. Nitrite tissue levels were similar across all species investigated. We then investigated the exact fractional myoglobin desaturation in an ex vivo approach when gassing with 1% oxygen. Within a short time frame myoglobin desaturated to 58±12%. Given that myoglobin significantly contributes to nitrite reduction under hypoxia, dose-response experiments using physiological to pharmacological nitrite concentrations were conducted. Along all concentrations, abrogation of myoglobin in mice impaired vasodilation. As reactive oxygen species may counteract the vasodilatory response, we used superoxide dismutase and its mimic tempol as well as catalase and ebselen to reduce the levels of reactive oxygen species during hypoxic vasodilation. Incubation of tempol in conjunction with catalase alone and catalase/ebselen increased the vasodilatory response to nitrite. Our study shows that modest hypoxia leads to a significant nitrite-dependent vessel relaxation. This requires the presence of vascular myoglobin for both physiological and pharmacological nitrite levels. Reactive oxygen species, in turn, modulate this vasodilation response.

  1. Invoking the Power of Thrombospondins: Regulation of Thrombospondins Expression

    PubMed Central

    Stenina-Adognravi, Olga

    2014-01-01

    Increasing evidence suggests critical functions of thrombospondins (TSPs) in a variety of physiological and pathological processes. With the growing understanding of the importance of these matricellular proteins, the need to understand the mechanisms of regulation of their expression and potential approaches to modulate their levels is also increasing. The regulation of TSPs expression is multi-leveled, cell- and tissue-specific, and very precise. However, the knowledge of mechanisms modulating the levels of TSPs is fragmented and incomplete. This review discusses the known mechanisms of regulation of TSPs levels and the gaps in our knowledge that prevent us from developing strategies to modulate the expression of these physiologically important proteins. PMID:24582666

  2. Reactive sulfur species regulate tRNA methylthiolation and contribute to insulin secretion

    PubMed Central

    Takahashi, Nozomu; Wei, Fan-Yan; Watanabe, Sayaka; Hirayama, Mayumi; Ohuchi, Yuya; Fujimura, Atsushi; Kaitsuka, Taku; Ishii, Isao; Sawa, Tomohiro; Nakayama, Hideki; Akaike, Takaaki; Tomizawa, Kazuhito

    2017-01-01

    The 2-methylthio (ms2) modification at A37 of tRNAs is critical for accurate decoding, and contributes to metabolic homeostasis in mammals. However, the regulatory mechanism of ms2 modification remains largely unknown. Here, we report that cysteine hydropersulfide (CysSSH), a newly identified reactive sulfur species, is involved in ms2 modification in cells. The suppression of intracellular CysSSH production rapidly reduced ms2 modification, which was rescued by the application of an exogenous CysSSH donor. Using a unique and stable isotope-labeled CysSSH donor, we show that CysSSH was capable of specifically transferring its reactive sulfur atom to the cysteine residues of ms2-modifying enzymes as well as ms2 modification. Furthermore, the suppression of CysSSH production impaired insulin secretion and caused glucose intolerance in both a pancreatic β-cell line and mouse model. These results demonstrate that intracellular CysSSH is a novel sulfur source for ms2 modification, and that it contributes to insulin secretion. PMID:27568003

  3. Reactive sulfur species regulate tRNA methylthiolation and contribute to insulin secretion.

    PubMed

    Takahashi, Nozomu; Wei, Fan-Yan; Watanabe, Sayaka; Hirayama, Mayumi; Ohuchi, Yuya; Fujimura, Atsushi; Kaitsuka, Taku; Ishii, Isao; Sawa, Tomohiro; Nakayama, Hideki; Akaike, Takaaki; Tomizawa, Kazuhito

    2017-01-09

    The 2-methylthio (ms(2)) modification at A37 of tRNAs is critical for accurate decoding, and contributes to metabolic homeostasis in mammals. However, the regulatory mechanism of ms(2) modification remains largely unknown. Here, we report that cysteine hydropersulfide (CysSSH), a newly identified reactive sulfur species, is involved in ms(2) modification in cells. The suppression of intracellular CysSSH production rapidly reduced ms(2) modification, which was rescued by the application of an exogenous CysSSH donor. Using a unique and stable isotope-labeled CysSSH donor, we show that CysSSH was capable of specifically transferring its reactive sulfur atom to the cysteine residues of ms(2)-modifying enzymes as well as ms(2) modification. Furthermore, the suppression of CysSSH production impaired insulin secretion and caused glucose intolerance in both a pancreatic β-cell line and mouse model. These results demonstrate that intracellular CysSSH is a novel sulfur source for ms(2) modification, and that it contributes to insulin secretion.

  4. Reactive cysteine persulfides and S-polythiolation regulate oxidative stress and redox signaling

    PubMed Central

    Ida, Tomoaki; Sawa, Tomohiro; Ihara, Hideshi; Tsuchiya, Yukihiro; Watanabe, Yasuo; Kumagai, Yoshito; Suematsu, Makoto; Motohashi, Hozumi; Fujii, Shigemoto; Matsunaga, Tetsuro; Yamamoto, Masayuki; Ono, Katsuhiko; Devarie-Baez, Nelmi O.; Xian, Ming; Fukuto, Jon M.; Akaike, Takaaki

    2014-01-01

    Using methodology developed herein, it is found that reactive persulfides and polysulfides are formed endogenously from both small molecule species and proteins in high amounts in mammalian cells and tissues. These reactive sulfur species were biosynthesized by two major sulfurtransferases: cystathionine β-synthase and cystathionine γ-lyase. Quantitation of these species indicates that high concentrations of glutathione persulfide (perhydropersulfide >100 μM) and other cysteine persulfide and polysulfide derivatives in peptides/proteins were endogenously produced and maintained in the plasma, cells, and tissues of mammals (rodent and human). It is expected that persulfides are especially nucleophilic and reducing. This view was found to be the case, because they quickly react with H2O2 and a recently described biologically generated electrophile 8-nitroguanosine 3′,5′-cyclic monophosphate. These results indicate that persulfides are potentially important signaling/effector species, and because H2S can be generated from persulfide degradation, much of the reported biological activity associated with H2S may actually be that of persulfides. That is, H2S may act primarily as a marker for the biologically active of persulfide species. PMID:24733942

  5. Up-regulation of reactivity and survival genes in astrocytes after exposure to short duration overpressure.

    PubMed

    Vandevord, Pamela J; Leung, Lai Yee; Hardy, Warren; Mason, Matthew; Yang, King H; King, Albert I

    2008-04-04

    Gurdjian et al. proposed decades ago that pressure gradients played a major factor in neuronal injury due to impact. In the late 1950s, their experiments on concussion demonstrated that the principal factor in the production of concussion in animals was the sudden increase of intracranial pressure accompanying head injury. They reported the increase in pressure severity correlated with an increase in 'altered cells' resulting in animal death. More recently, Hardy et al. (2006) demonstrated the presence of transient pressure pulses with impact conditions. These studies indicate that short duration overpressure should be further examined as a mechanism of traumatic brain injury (TBI). In the present study, we designed and fabricated a barochamber that simulated overpressure noted in various head injury studies. We tested the effect of overpressure on astrocytes. Expressions of apoptotic, reactivity and survival genes were examined at 24, 48 and 72 h post-overpressure exposure. At 24 h, we found elevated levels of reactivity and survival gene expression. By 48 h, a decreased expression of apoptotic genes was demonstrated. This study reinforces the hypothesis that transient pressure acts to instigate the cellular response displayed following TBI.

  6. An ionization region model of the reactive Ar/O2 high power impulse magnetron sputtering discharge

    NASA Astrophysics Data System (ADS)

    Gudmundsson, J. T.; Lundin, D.; Brenning, N.; Raadu, M. A.; Huo, Chunqing; Minea, T. M.

    2016-12-01

    A new reactive ionization region model (R-IRM) is developed to describe the reactive Ar/O2 high power impulse magnetron sputtering (HiPIMS) discharge with a titanium target. It is then applied to study the temporal behavior of the discharge plasma parameters such as electron density, the neutral and ion composition, the ionization fraction of the sputtered vapor, the oxygen dissociation fraction, and the composition of the discharge current. We study and compare the discharge properties when the discharge is operated in the two well established operating modes, the metal mode and the poisoned mode. Experimentally, it is found that in the metal mode the discharge current waveform displays a typical non-reactive evolution, while in the poisoned mode the discharge current waveform becomes distinctly triangular and the current increases significantly. Using the R-IRM we explore the current increase and find that when the discharge is operated in the metal mode Ar+ and Ti+ -ions contribute most significantly (roughly equal amounts) to the discharge current while in the poisoned mode the Ar+ -ions contribute most significantly to the discharge current and the contribution of O+ -ions, Ti+ -ions, and secondary electron emission is much smaller. Furthermore, we find that recycling of atoms coming from the target, that are subsequently ionized, is required for the current generation in both modes of operation. From the R-IRM results it is found that in the metal mode self-sputter recycling dominates and in the poisoned mode working gas recycling dominates. We also show that working gas recycling can lead to very high discharge currents but never to a runaway. It is concluded that the dominating type of recycling determines the discharge current waveform.

  7. Design of an Adaptive Power Regulation Mechanism and a Nozzle for a Hydroelectric Power Plant Turbine Test Rig

    NASA Astrophysics Data System (ADS)

    Mert, Burak; Aytac, Zeynep; Tascioglu, Yigit; Celebioglu, Kutay; Aradag, Selin; ETU Hydro Research Center Team

    2014-11-01

    This study deals with the design of a power regulation mechanism for a Hydroelectric Power Plant (HEPP) model turbine test system which is designed to test Francis type hydroturbines up to 2 MW power with varying head and flow(discharge) values. Unlike the tailor made regulation mechanisms of full-sized, functional HEPPs; the design for the test system must be easily adapted to various turbines that are to be tested. In order to achieve this adaptability, a dynamic simulation model is constructed in MATLAB/Simulink SimMechanics. This model acquires geometric data and hydraulic loading data of the regulation system from Autodesk Inventor CAD models and Computational Fluid Dynamics (CFD) analysis respectively. The dynamic model is explained and case studies of two different HEPPs are performed for validation. CFD aided design of the turbine guide vanes, which is used as input for the dynamic model, is also presented. This research is financially supported by Turkish Ministry of Development.

  8. Formation of hydrogenated amorphous carbon films by reactive high power impulse magnetron sputtering containing C2H2 gas

    NASA Astrophysics Data System (ADS)

    Kimura, Takashi; Kamata, Hikaru

    2015-09-01

    Diamond-like carbon (DLC) films have attracted interest for material industries, because they have unique properties. Hydrogenated amorphous carbon films are prepared by reactive high power impulse magnetron sputtering (HiPIMS) containing C2H2 gas and the properties of the films produced in Ar/C2H2 and Ne/C2H2 HiPIMS are compared. Production of hydrocarbon radicals and their ions strongly depends on both electron temperature and electron density in HiPIMS. Therefore, the influence of the difference in buffer gas (Ar and Ne) on the film properties is also valuable to investigate. The film preparation is performed at an average power of 60 W and a repetition frequency of 110 Hz. Total pressure ranges between 0.3 and 2 Pa. The maximum of instantaneous power is about 20-25 kW, and the magnitude of the current is 35 A. A negative pulse voltage is applied to the substrates for about 15 μs after the target voltage changed from about -500 V to 0 V. Hardness of the films prepared by Ar/C2H2 HiPIMS monotonically decreases with increasing the total pressure, whereas that of the films prepared by Ne/C2H2 HiPIMS does not strongly depend on the total pressure. This work is partially supported by JSPS KAKENHI Grant Number 26420230.

  9. Voltage regulator for battery power source. [using a bipolar transistor

    NASA Technical Reports Server (NTRS)

    Black, J. M. (Inventor)

    1979-01-01

    A bipolar transistor in series with the battery as the control element also in series with a zener diode and a resistor is used to maintain a predetermined voltage until the battery voltage decays to very nearly the predetermined voltage. A field effect transistor between the base of the bipolar transistor and a junction between the zener diode and resistor regulates base current of the bipolar transistor, thereby regulating the conductivity of the bipolar transistor for control of the output voltage.

  10. The Keap1/Nrf2 Protein Axis Plays a Role in Osteoclast Differentiation by Regulating Intracellular Reactive Oxygen Species Signaling*

    PubMed Central

    Kanzaki, Hiroyuki; Shinohara, Fumiaki; Kajiya, Mikihito; Kodama, Tetsuya

    2013-01-01

    Reactive oxygen species (ROS) act as intracellular signaling molecules in the regulation of receptor activator of nuclear factor-κB ligand (RANKL)-dependent osteoclast differentiation, but they also have cytotoxic effects that include peroxidation of lipids and oxidative damage to proteins and DNA. Cellular protective mechanisms against oxidative stress include transcriptional control of cytoprotective enzymes by the transcription factor, nuclear factor E2-related factor 2 (Nrf2). This study investigated the relationship between Nrf2 and osteoclastogenesis. Stimulation of osteoclast precursors (mouse primary peritoneal macrophages and RAW 264.7 cells) with RANKL resulted in the up-regulation of kelch-like ECH-associated protein 1 (Keap1), a negative regulator of Nrf2. It also decreased the Nrf2/Keap1 ratio, and it down-regulated cytoprotective enzymes (heme oxygenase-1, γ-glutamylcysteine synthetase, and glucose-6-phosphate dehydrogenase). Nrf2 overexpression up-regulated the expression of cytoprotective enzymes, decreased ROS levels, decreased the number of tartrate-resistant acid phosphatase-positive multinucleated cells, reduced marker genes for osteoclast differentiation, and attenuated bone destruction in both in vitro and in vivo models. Overexpression of Keap1 or RNAi knockdown of Nrf2 exerted the opposite actions. In addition, in vivo local Nrf2 overexpression attenuated lipopolysaccharide-mediated RANKL-dependent cranial bone destruction in vivo. This is the first study to show that the Keap1/Nrf2 axis regulates RANKL-dependent osteoclastogenesis through modulation of intracellular ROS signaling via expression of cytoprotective enzymes. This raises the exciting possibility that the Keap1-Nrf2 axis may be a therapeutic target for the treatment of bone destructive disease. PMID:23801334

  11. Self-regulating control of parasitic loads in a fuel cell power system

    NASA Technical Reports Server (NTRS)

    Vasquez, Arturo (Inventor)

    2011-01-01

    A fuel cell power system comprises an internal or self-regulating control of a system or device requiring a parasitic load. The internal or self-regulating control utilizes certain components and an interconnection scheme to produce a desirable, variable voltage potential (i.e., power) to a system or device requiring parasitic load in response to varying operating conditions or requirements of an external load that is connected to a primary fuel cell stack of the system. Other embodiments comprise a method of designing such a self-regulated control scheme and a method of operating such a fuel cell power system.

  12. Perspective: Is there a hysteresis during reactive High Power Impulse Magnetron Sputtering (R-HiPIMS)?

    NASA Astrophysics Data System (ADS)

    Strijckmans, K.; Moens, F.; Depla, D.

    2017-02-01

    This paper discusses a few mechanisms that can assist to answer the title question. The initial approach is to use an established model for DC magnetron sputter deposition, i.e., RSD2013. Based on this model, the impact on the hysteresis behaviour of some typical HiPIMS conditions is investigated. From this first study, it becomes clear that the probability to observe hysteresis is much lower as compared to DC magnetron sputtering. The high current pulses cannot explain the hysteresis reduction. Total pressure and material choice make the abrupt changes less pronounced, but the implantation of ionized metal atoms that return to the target seems to be the major cause. To further substantiate these results, the analytical reactive sputtering model is coupled with a published global plasma model. The effect of metal ion implantation is confirmed. Another suggested mechanism, i.e., gas rarefaction, can be ruled out to explain the hysteresis reduction. But perhaps the major conclusion is that at present, there are too little experimental data available to make fully sound conclusions.

  13. Regulation of signal transduction by reactive oxygen species in the cardiovascular system.

    PubMed

    Brown, David I; Griendling, Kathy K

    2015-01-30

    Oxidative stress has long been implicated in cardiovascular disease, but more recently, the role of reactive oxygen species (ROS) in normal physiological signaling has been elucidated. Signaling pathways modulated by ROS are complex and compartmentalized, and we are only beginning to identify the molecular modifications of specific targets. Here, we review the current literature on ROS signaling in the cardiovascular system, focusing on the role of ROS in normal physiology and how dysregulation of signaling circuits contributes to cardiovascular diseases, including atherosclerosis, ischemia-reperfusion injury, cardiomyopathy, and heart failure. In particular, we consider how ROS modulate signaling pathways related to phenotypic modulation, migration and adhesion, contractility, proliferation and hypertrophy, angiogenesis, endoplasmic reticulum stress, apoptosis, and senescence. Understanding the specific targets of ROS may guide the development of the next generation of ROS-modifying therapies to reduce morbidity and mortality associated with oxidative stress.

  14. Reciprocal regulation of TGF-β and reactive oxygen species: A perverse cycle for fibrosis

    PubMed Central

    Liu, Rui-Ming; Desai, Leena P.

    2015-01-01

    Transforming growth factor beta (TGF-β) is the most potent pro-fibrogenic cytokine and its expression is increased in almost all of fibrotic diseases. Although signaling through Smad pathway is believed to play a central role in TGF-β's fibrogenesis, emerging evidence indicates that reactive oxygen species (ROS) modulate TGF-β's signaling through different pathways including Smad pathway. TGF-β1 increases ROS production and suppresses antioxidant enzymes, leading to a redox imbalance. ROS, in turn, induce/activate TGF-β1 and mediate many of TGF-β's fibrogenic effects, forming a vicious cycle (see graphic flow chart on the right). Here, we review the current knowledge on the feed-forward mechanisms between TGF-β1 and ROS in the development of fibrosis. Therapeutics targeting TGF-β-induced and ROS-dependent cellular signaling represents a novel approach in the treatment of fibrotic disorders. PMID:26496488

  15. State regulation and power plant productivity: background and recommendations

    SciTech Connect

    Not Available

    1980-09-01

    This report was prepared by representatives of several state regulatory agencies. It is a guide to some of the activities currently under way in state agencies to promote increased availability of electrical generating power plants. Standard measures of plant performance are defined and the nature of data bases that report such measures is discussed. It includes reviews of current state, federal, and industry programs to enhance power plant productivity and provides detailed outlines of programs in effect in California, Illinois, Michigan, New York, North Carolina, Ohio, and Texas. A number of actions are presented that could be adopted by state regulatory agencies, depending on local conditions. They include: develop a commission position or policy statement to encourage productivity improvements by utilities; coordinate state efforts with ongoing industry and government programs to improve the acquisition of power plant performance data and the maintenance of quality information systems; acquire the capability to perform independent analyses of power plant productivity; direct the establishment of productivity improvement programs, including explicit performance objectives for both existing and planned power plants, and a performance program; establish a program of incentives to motivate productivity improvement activities; and participate in ongoing efforts at all levels and initiate new actions to promote productivity improvements.

  16. Note: A new regulation method of stable operation of high power cathode ion source

    SciTech Connect

    Jiang, C. C.; Xie, Y. H. Hu, C. D.; Xie, Y. L.; Liu, S.; Liang, L. Z.; Liu, Z. M.

    2015-05-15

    The hot cathode ion source will tend to be unstable when operated with high power and long pulse. In order to achieve stable operation, a new regulation method based on the arc power (discharge power) feedback control was designed and tested on the hot cathode ion source test bed with arc discharge and beam extraction. The results show that the new regulation method can achieve stable arc discharge and beam extraction. It verifies the success of feedback control of arc source with arc power.

  17. Cortisol Reactivity and Regulation Associated with Shame Responding in Early Childhood

    ERIC Educational Resources Information Center

    Mills, Rosemary S. L.; Imm, Gorette P.; Walling, Bobbi R.; Weiler, Hope A.

    2008-01-01

    The purpose of this study was to characterize cortisol response and regulation associated with shame responding in early childhood and to examine how general the relation between shame and cortisol is. It was predicted that children responding to task failure with shame would show a larger and more prolonged cortisol response than other children.…

  18. Quality Certification, Regulation and Power in Fair Trade

    ERIC Educational Resources Information Center

    Renard, Marie-Christine

    2005-01-01

    This article examines governance changes and shifting power relations within the fair-labelling network. These shifts are framed analytically by reference to broader changes in the agrofoods sector tied to the increasingly key role played by quality relations and standards in the production and marketing of food. The author argues that evident…

  19. Low Power Television: The Impact of the Final Regulations.

    ERIC Educational Resources Information Center

    Hsiung, James C.; And Others

    In August 1978, the Federal Communications Commission (FCC) began studying the question of how to increase the diversity and coverage of television broadcast services either by modifying the television translator rules or by creating a new low power television service (LPTV). In Septemer 1980, the FCC finally adopted a "Notice of Proposed…

  20. Autophagy inhibition enhances silibinin-induced apoptosis by regulating reactive oxygen species production in human prostate cancer PC-3 cells.

    PubMed

    Kim, Sang-Hun; Kim, Kwang-Youn; Yu, Sun-Nyoung; Park, Seul-Ki; Choi, Hyeun-Deok; Ji, Jae-Hoon; Ahn, Soon-Cheol

    Silibinin is a major bioactive component of silymarin and has anticancer effects on cancer cell line and has been used as a supportive therapy for chronic inflammatory liver condition. These anticancer effects of silibinin have been demonstrated both in vitro and in vivo cancer models. Although various evidences showed apoptosis signaling pathways by silibinin, there is no report to address the clearly mechanism of silibinin-induced autophagy in prostate cancer PC-3 cells. Our study showed that silibinin triggered autophagy through up-regulation of microtubule-associated protein 1 light chain 3 (LC3)-II, formation of acidic vesicular organelles (AVO) and punctuate of GFP-LC3, which was inhibited by 3-methyladenine (3-MA), an inhibitor of specific autophagy. In addition, silibinin induced autophagy through production of reactive oxygen species (ROS). Inhibition of ROS with diphenyleneiodonium (DPI), a ROS inhibitor, attenuated silibinin-triggered autophagy. Inhibition of autophagy with 3-MA enhanced the silibinin-induced apoptosis through the regulation of caspase-3 and PARP. These results suggested that silibinin induced autophagy by regulating ROS and its mechanism played a protective role against apoptosis in PC-3 cells.

  1. Respiratory Sinus Arrhythmia Reactivity Predicts Emotion Regulation and Depressive Symptoms in At-risk and Control Children

    PubMed Central

    Gentzler, Amy L.; Santucci, Aimee K.; Kovacs, Maria; Fox, Nathan A.

    2010-01-01

    We examined respiratory sinus arrhythmia (RSA), emotion regulation (ER), and prospective depressive symptoms in children at risk for depression and controls. Of the 65 children (35 boys; 5 – 13 years) in the sample, 39 had a parent with childhood-onset mood disorder and 26 had a parent with no history of major psychiatric disorder. RSA during pre- and post-film baselines and RSA reactivity to sad film clip were measured. Later, children’s ER responses (focusing on sad/distressing affect) were assessed using a parent-reported questionnaire, and depressive symptoms were measured via clinical ratings. Results indicated that, compared to the initial baseline, a greater decrease in RSA (i.e. more vagal withdrawal) in response to the sad film clip predicted more adaptive ER responses and lower levels of clinician-rated depressive symptoms. However, tests for ER as a mediator of the association between RSA reactivity and depressive symptoms were precluded because maladaptive, but not adaptive, ER was associated with depressive symptoms. Overall, results suggest that cardiac vagal withdrawal (a greater decrease in RSA) in response to an emotional stimulus reflects more adaptive parasympathetic activity, which could facilitate children’s ability to effectively manage their sadness and distress and predict lower risk of depressive symptoms over time. PMID:19596044

  2. Inorganic Polyphosphates Regulate Hexokinase Activity and Reactive Oxygen Species Generation in Mitochondria of Rhipicephalus (Boophilus) microplus Embryo

    PubMed Central

    Fraga, Amanda; Moraes, Jorge; da Silva, José Roberto; Costa, Evenilton P.; Menezes, Jackson; da Silva Vaz Jr, Itabajara; Logullo, Carlos; da Fonseca, Rodrigo Nunes; Campos, Eldo

    2013-01-01

    The physiological roles of polyphosphates (poly P) recently found in arthropod mitochondria remain obscure. Here, the possible involvement of poly P with reactive oxygen species generation in mitochondria of Rhipicephalus microplus embryos was investigated. Mitochondrial hexokinase and scavenger antioxidant enzymes, such as superoxide dismutase, catalase, and glutathione reductase were assayed during embryogenesis of R. microplus. The influence of poly P3 and poly P15 were analyzed during the period of higher enzymatic activity during embryogenesis. Both poly Ps inhibited hexokinase activity by up to 90% and, interestingly, the mitochondrial membrane exopolyphosphatase activity was stimulated by the hexokinase reaction product, glucose-6-phosphate. Poly P increased hydrogen peroxide generation in mitochondria in a situation where mitochondrial hexokinase is also active. The superoxide dismutase, catalase and glutathione reductase activities were higher during embryo cellularization, at the end of embryogenesis and during embryo segmentation, respectively. All of the enzymes were stimulated by poly P3. However, superoxide dismutase was not affected by poly P15, catalase activity was stimulated only at high concentrations and glutathione reductase was the only enzyme that was stimulated in the same way by both poly Ps. Altogether, our results indicate that inorganic polyphosphate and mitochondrial membrane exopolyphosphatase regulation can be correlated with the generation of reactive oxygen species in the mitochondria of R. microplus embryos. PMID:23983617

  3. Candida albicans erythroascorbate peroxidase regulates intracellular methylglyoxal and reactive oxygen species independently of D-erythroascorbic acid.

    PubMed

    Kwak, Min-Kyu; Song, Sung-Hyun; Ku, MyungHee; Kang, Sa-Ouk

    2015-07-08

    Candida albicans D-erythroascorbate peroxidase (EAPX1), which can catalyze the oxidation of D-erythroascorbic acid (EASC) to water, was observed to be inducible in EAPX1-deficient and EAPX1-overexpressing cells via activity staining. EAPX1-deficient cells have remarkably increased intracellular reactive oxygen species and methylglyoxal independent of the intracellular EASC content. The increased methylglyoxal caused EAPX1-deficient cells to activate catalase-peroxidase and cytochrome c peroxidase, which led to defects in cell growth, viability, mitochondrial respiration, filamentation and virulence. These findings indicate that EAPX1 mediates cell differentiation and virulence by regulating intracellular methylglyoxal along with oxidative stresses, regardless of endogenous EASC biosynthesis or alternative oxidase expression.

  4. HVCN1 modulates BCR signal strength via regulation of BCR-dependent generation of reactive oxygen species

    PubMed Central

    Capasso, Melania; Bhamrah, Mandeep K; Henley, Tom; Boyd, Robert S; Langlais, Claudia; Cain, Kelvin; Dinsdale, David; Pulford, Karen; Kan, Mahmood; Musset, Boris; Cherny, Vladimir V; Morgan, Deri; Gascoyne, Randy D; Vigorito, Elena; DeCoursey, Thomas E; MacLennan, Ian C M; Dyer, Martin J S

    2011-01-01

    Voltage-gated proton currents regulate generation of reactive oxygen species (ROS) in phagocytic cells. In B cells, stimulation of the B cell antigen receptor (BCR) results in the production of ROS that participate in B cell activation, but the involvement of proton channels is unknown. We report here that the voltage-gated proton channel HVCN1 associated with the BCR complex and was internalized together with the BCR after activation. BCR-induced generation of ROS was lower in HVCN1-deficient B cells, which resulted in attenuated BCR signaling via impaired BCR-dependent oxidation of the tyrosine phosphatase SHP-1. This resulted in less activation of the kinases Syk and Akt, impaired mitochondrial respiration and glycolysis, and diminished antibody responses in vivo. Our findings identify unanticipated functions for proton channels in B cells and demonstrate the importance of ROS in BCR signaling and downstream metabolism. PMID:20139987

  5. Fine tuning of reactive oxygen species homeostasis regulates primed immune responses in Arabidopsis.

    PubMed

    Pastor, Victoria; Luna, Estrella; Ton, Jurriaan; Cerezo, Miguel; García-Agustín, Pilar; Flors, Victor

    2013-11-01

    Selected stimuli can prime the plant immune system for a faster and stronger defense reaction to pathogen attack. Pretreatment of Arabidopsis with the chemical agent β-aminobutyric acid (BABA) augmented H2O2 and callose production after induction with the pathogen-associated molecular pattern (PAMP) chitosan, or inoculation with the necrotrophic fungus Plectosphaerella cucumerina. However, BABA failed to prime H2O2 and callose production after challenge with the bacterial PAMP Flg22. Analysis of Arabidopsis mutants in reactive oxygen species (ROS) production (rbohD) or ROS scavenging (pad2, vtc1, and cat2) suggested a regulatory role for ROS homeostasis in priming of chitosan- and P. cucumerina-inducible callose and ROS. Moreover, rbohD and pad2 were both impaired in BABA-induced resistance against P. cucumerina. Gene expression analysis revealed direct induction of NADPH/respiratory burst oxidase protein D (RBOHD), γ-glutamylcysteine synthetase 1 (GSH1), and vitamin C defective 1 (VTC1) genes after BABA treatment. Conversely, ascorbate peroxidase 1 (APX1) transcription was repressed by BABA after challenge with chitosan or P. cucumerina, probably to provide a more oxidized environment in the cell and facilitate augmented ROS accumulation. Measuring ratios between reduced and oxidized glutathione confirmed that augmented defense expression in primed plants is associated with a more oxidized cellular status. Together, our data indicate that an altered ROS equilibrium is required for augmented defense expression in primed plants.

  6. C-Reactive Protein: An In-Depth Look into Structure, Function, and Regulation

    PubMed Central

    Salazar, Juan; Martínez, María Sofía; Chávez-Castillo, Mervin; Núñez, Victoria; Añez, Roberto; Torres, Yaquelin; Toledo, Alexandra; Chacín, Maricarmen; Silva, Carlos; Pacheco, Enrique; Rojas, Joselyn; Bermúdez, Valmore

    2014-01-01

    Cardiovascular disease is the leading cause of morbidity and mortality in the adult population worldwide, with atherosclerosis being its key pathophysiologic component. Atherosclerosis possesses a fundamental chronic inflammatory aspect, and the involvement of numerous inflammatory molecules has been studied in this scenario, particularly C-reactive protein (CRP). CRP is a plasma protein with strong phylogenetic conservation and high resistance to proteolysis, predominantly synthesized in the liver in response to proinflammatory cytokines, especially IL-6, IL-1β, and TNF. CRP may intervene in atherosclerosis by directly activating the complement system and inducing apoptosis, vascular cell activation, monocyte recruitment, lipid accumulation, and thrombosis, among other actions. Moreover, CRP can dissociate in peripheral tissue—including atheromatous plaques—from its native pentameric form into a monomeric form, which may also be synthesized de novo in extrahepatic sites. Each form exhibits distinct affinities for ligands and receptors, and exerts different effects in the progression of atherosclerosis. In view of epidemiologic evidence associating high CRP levels with cardiovascular risk—reflecting the biologic impact it bears on atherosclerosis—measurement of serum levels of high-sensitivity CRP has been proposed as a tool for assessment of cardiovascular risk. PMID:27433484

  7. Role of reactive oxygen species in regulation of glucose transport in skeletal muscle during exercise.

    PubMed

    Katz, Abram

    2016-06-01

    Glucose derived from extracellular sources serves as an energy source in virtually all eukaryotic cells, including skeletal muscle. Its contribution to energy turnover increases with exercise intensity up to moderately heavy workloads. However, at very high workloads, the contribution of extracellular glucose to energy turnover is negligible, despite the high rate of glucose transport. Reactive oxygen species (ROS) are involved in the stimulation of glucose transport in isolated skeletal muscle preparations during intense repeated contractions. Consistent with this observation, heavy exercise is associated with significant production of ROS. However, during more mild to moderate stimulation or exercise conditions (in vitro, in situ and in vivo) antioxidants do not affect glucose transport. It is noteworthy that the production of ROS is limited or not observed under these conditions and that the concentration of the antioxidant used was extremely low. The results to date suggest that ROS involvement in activation of glucose transport occurs primarily during intense short-term exercise and that other mechanisms are involved during mild to moderate exercise. What remains puzzling is why ROS-mediated activation of glucose transport would occur under conditions where glucose transport is highest and utilization (i.e. phosphorylation of glucose by hexokinase) is low. Possibly ROS production is involved in priming glucose transport during heavy exercise to accelerate glycogen biogenesis during the initial recovery period after exercise, as well as altering other aspects of intracellular metabolism.

  8. Lanthanum regulates the reactive oxygen species in the roots of rice seedlings

    PubMed Central

    Liu, Dongwu; Zheng, Shengnan; Wang, Xue

    2016-01-01

    In this study, the effects of La3+ on the reactive oxygen species (ROS) and antioxidant metabolism were studied in the roots of rice (Oryza sativa L. cv Shengdao 16) exposed to increasing concentrations of La3+ (0.05, 0.1, 0.5, 1.0, and 1.5 mM). The level of hydrogen peroxide, superoxide anion, and malondialdehyde was increased by 0.5, 1.0 and 1.5 mM La3+, and the activity of catalase and peroxidase was increased by 0.05 and 0.1 mM La3+. However, La3+ treatments stimulated superoxide dismutase activity in the roots of rice seedlings at all tested concentrations. In addition, the probe 2′,7′-dichlorofluorescein diacetate (H2DCF-DA) was used to investigate the instantaneous change of ROS in the root cells with the laser-scanning confocal microscopy. The result indicated that ROS level was declined after treated with 0.05 mM La3+. The results showed that the appropriate concentration of La3+ decreased the level of ROS, and hormetic effects on the antioxidant metabolism were found in the roots of rice exposed to 0.05, 0.1, 0.5, 1.0, and 1.5 mM La3+. PMID:27546334

  9. Regulation of Murine Intestinal Inflammation by Reactive Metabolites of Oxygen and Nitrogen

    PubMed Central

    Krieglstein, Christian F.; Cerwinka, Wolfgang H.; Laroux, F. Stephen; Salter, James W.; Russell, Janice M.; Schuermann, Guido; Grisham, Matthew B.; Ross, Christopher R.; Granger, D. Neil

    2001-01-01

    Several reports have implicated reactive oxygen and nitrogen metabolites (RONS) in the initiation and/or progression of inflammatory bowel diseases (IBDs). We have investigated the role of three key RONS-metabolizing enzymes (inducible nitric oxide synthase [iNOS], superoxide dismutase [SOD], nicotinamide adenine dinucleotide phosphate [NADPH] oxidase) in a murine model of IBD. Mice genetically deficient (−/−) in either iNOS or the p47phox subunit of NADPH oxidase, transgenic (Tg) mice that overexpress SOD, and their respective wild-type (WT) littermates were fed dextran sulfate sodium (DSS) in drinking water for 7 days to induce colitis. In addition, the specific iNOS inhibitor 1400W was used in DSS-treated WT and p47phox−/− mice. WT mice responded to DSS feeding with progressive weight loss, bloody stools, elevated serum NOX and colonic mucosal injury with neutrophil infiltration. Both the onset and severity of colitis were significantly attenuated in iNOS−/− and 1400W-treated WT mice. While the responses to DSS did not differ between WT and p47phox−/− mice, enhanced protection was noted in 1400W-treated p47phox−/− mice. Interestingly, SODTg mice exhibited more severe colitis than their WT littermates. These findings reveal divergent roles for superoxide and iNOS-derived NO in intestinal inflammation. PMID:11696587

  10. Reactive Oxygen Species in the Regulation of Synaptic Plasticity and Memory

    PubMed Central

    Klann, Eric

    2011-01-01

    Abstract The brain is a metabolically active organ exhibiting high oxygen consumption and robust production of reactive oxygen species (ROS). The large amounts of ROS are kept in check by an elaborate network of antioxidants, which sometimes fail and lead to neuronal oxidative stress. Thus, ROS are typically categorized as neurotoxic molecules and typically exert their detrimental effects via oxidation of essential macromolecules such as enzymes and cytoskeletal proteins. Most importantly, excessive ROS are associated with decreased performance in cognitive function. However, at physiological concentrations, ROS are involved in functional changes necessary for synaptic plasticity and hence, for normal cognitive function. The fine line of role reversal of ROS from good molecules to bad molecules is far from being fully understood. This review focuses on identifying the multiple sources of ROS in the mammalian nervous system and on presenting evidence for the critical and essential role of ROS in synaptic plasticity and memory. The review also shows that the inability to restrain either age- or pathology-related increases in ROS levels leads to opposite, detrimental effects that are involved in impairments in synaptic plasticity and memory function. Antioxid. Redox Signal. 14, 2013–2054. PMID:20649473

  11. Dynamic Power Flow Controller: Compact Dynamic Phase Angle Regulators for Transmission Power Routing

    SciTech Connect

    2012-01-03

    GENI Project: Varentec is developing compact, low-cost transmission power controllers with fractional power rating for controlling power flow on transmission networks. The technology will enhance grid operations through improved use of current assets and by dramatically reducing the number of transmission lines that have to be built to meet increasing contributions of renewable energy sources like wind and solar. The proposed transmission controllers would allow for the dynamic control of voltage and power flow, improving the grid’s ability to dispatch power in real time to the places where it is most needed. The controllers would work as fail-safe devices whereby the grid would be restored to its present operating state in the event of a controller malfunction instead of failing outright. The ability to affordably and dynamically control power flow with adequate fail-safe switchgear could open up new competitive energy markets which are not possible under the current regulatory structure and technology base.

  12. PFKFB3-mediated glycolysis is involved in reactive astrocyte proliferation after oxygen-glucose deprivation/reperfusion and is regulated by Cdh1.

    PubMed

    Lv, Youyou; Zhang, Bo; Zhai, Chunchun; Qiu, Jin; Zhang, Yue; Yao, Wenlong; Zhang, Chuanhan

    2015-12-01

    Reactive astrocyte proliferation is involved in many central degenerative diseases. The enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase isoform 3 (PFKFB3), an allosteric activator of 6-phosphofructo-1-kinase (PFK1), controls glycolytic flux. Furthermore, APC/C-Cdh1 plays a crucial role in brain metabolism by regulating PFKFB3 expression. Previous studies have defined the roles of PFKFB3-mediated glycolysis in pathological angiogenesis, cell autophagy, and amyloid plaque deposition in proliferating cells. However, the role of PFKFB3 in reactive astrocyte proliferation after cerebral ischemia is unknown. In this study, we cultured rat primary cortical astrocytes and established an oxygen-glucose deprivation/reperfusion (OGD/R) model to mimic cerebral ischemia in vivo. Astrocyte proliferation was measured by western blotting for proliferating cell nuclear antigen (PCNA) and by EdU incorporation. We found that OGD/R up-regulated PFKFB3 and PFK1 expression, which was accompanied by reactive astrocyte proliferation. Knockdown of PFKFB3 by siRNA transfection significantly inhibited reactive astrocyte proliferation and lactate release, an indicator of glycolysis. We found that PFKFB3 and PFK1 expression were down-regulated and lactate release was decreased when OGD/R-induced astrocyte proliferation was inhibited by a Cdh1-expressing lentivirus. Thus, reactive astrocyte proliferation can be effectively suppressed by down-regulation of PFKFB3 through control of glycolytic flux, which is downstream of APC/C-Cdh1.

  13. Programmable high voltage power supply with regulation confined to the high voltage section

    NASA Technical Reports Server (NTRS)

    Castell, Karen D. (Inventor); Ruitberg, Arthur P. (Inventor)

    1994-01-01

    A high voltage power supply in a dc-dc converter configuration includes a pre-regulator which filters and regulates the dc input and drives an oscillator which applies, in turn, a low voltage ac signal to the low side of a step-up high voltage transformer. The high voltage side of the transformer drives a voltage multiplier which provides a stepped up dc voltage to an output filter. The output voltage is sensed by a feedback network which then controls a regulator. Both the input and output of the regulator are on the high voltage side, avoiding isolation problems. The regulator furnishes a portion of the drive to the voltage multiplier, avoiding having a regulator in series with the load with its attendant, relatively high power losses. This power supply is highly regulated, has low power consumption, a low parts count and may be manufactured at low cost. The power supply has a programmability feature that allows for the selection of a large range of output voltages.

  14. Real power regulation design for multi-terminal VSC-HVDC systems

    NASA Astrophysics Data System (ADS)

    Li, Guo-Jie; Ruan, Si-Ye; Lie, Tek

    2013-06-01

    A multi-terminal voltage-source-converter (VSC) based high voltage direct current (HVDC) system is concerned for its flexibility and reliability. In this study, a control strategy for multiple VSCs is proposed to auto-share the real power variation without changing control mode, which is based on "dc voltage droop" power regulation functions. With the proposed power regulation design, the multiple VSCs automatically share the real power change and the VSC-HVDC system is stable even under loss of any one converter while there is no overloading for any individual converter. Simulation results show that it is effective to balance real power for power disturbance and thus improves operation reliability for the multi-terminal VSC-HVDC system by the proposed control strategy.

  15. 75 FR 3985 - Trade Regulation Rule Relating to Power Output Claims for Amplifiers Utilized in Home...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-26

    ... CFR Part 432 Trade Regulation Rule Relating to Power Output Claims for Amplifiers Utilized in Home... Rule Relating to Power Output Claims for Amplifiers Utilized in Home Entertainment Products (``Amplifier Rule'' or ``Rule''), as part of the Commission's systematic review of all current...

  16. Early Childhood Teachers and Regulation: Complicating Power Relations Using a Foucauldian Lens

    ERIC Educational Resources Information Center

    Fenech, Marianne; Sumsion, Jennifer

    2007-01-01

    This article both supports and complicates the positioning of reconceptualists who frame the regulation of early childhood services as repressive. Drawing on Foucault's construction of power and, in particular, his notion of an "analytics of power", the authors analyse findings from an Australian study investigating university-qualified…

  17. Generation of reactive astrocytes from NG2 cells is regulated by sonic hedgehog.

    PubMed

    Honsa, Pavel; Valny, Martin; Kriska, Jan; Matuskova, Hana; Harantova, Lenka; Kirdajova, Denisa; Valihrach, Lukas; Androvic, Peter; Kubista, Mikael; Anderova, Miroslava

    2016-09-01

    NG2 cells, a fourth glial cell type in the adult mammalian central nervous system, produce oligodendrocytes in the healthy nervous tissue, and display wide differentiation potential under pathological conditions, where they could give rise to reactive astrocytes. The factors that control the differentiation of NG2 cells after focal cerebral ischemia (FCI) are largely unknown. Here, we used transgenic Cspg4-cre/Esr1/ROSA26Sortm14(CAG-tdTomato) mice, in which tamoxifen administration triggers the expression of red fluorescent protein (tomato) specifically in NG2 cells and cells derived therefrom. Differentiation potential (in vitro and in vivo) of tomato-positive NG2 cells from control or postischemic brains was determined using the immunohistochemistry, single cell RT-qPCR and patch-clamp method. The ischemic injury was induced by middle cerebral artery occlusion, a model of FCI. Using genetic fate-mapping method, we identified sonic hedgehog (Shh) as an important factor that influences differentiation of NG2 cells into astrocytes in vitro. We also manipulated Shh signaling in the adult mouse brain after FCI. Shh signaling activation significantly increased the number of astrocytes derived from NG2 cells in the glial scar around the ischemic lesion, while Shh signaling inhibition caused the opposite effect. Since Shh signaling modifications did not change the proliferation rate of NG2 cells, we can conclude that Shh has a direct influence on the differentiation of NG2 cells and therefore, on the formation and composition of a glial scar, which consequently affects the degree of the brain damage. GLIA 2016;64:1518-1531.

  18. Reactive oxygen species regulated mitochondria-mediated apoptosis in PC12 cells exposed to chlorpyrifos

    SciTech Connect

    Lee, Jeong Eun; Park, Jae Hyeon; Shin, In Chul; Koh, Hyun Chul

    2012-09-01

    Reactive oxidative species (ROS) generated by environmental toxicants including pesticides could be one of the factors underlying the neuronal cell damage in neurodegenerative diseases. In this study we found that chlorpyrifos (CPF) induced apoptosis in dopaminergic neuronal components of PC12 cells as demonstrated by the activation of caspases and nuclear condensation. Furthermore, CPF also reduced the tyrosine hydroxylase-positive immunoreactivity in substantia nigra of the rat. In addition, CPF induced inhibition of mitochondrial complex I activity. Importantly, N-acetyl cysteine (NAC) treatment effectively blocked apoptosis via the caspase-9 and caspase-3 pathways while NAC attenuated the inhibition of mitochondrial complex I activity as well as the oxidative metabolism of dopamine (DA). These results demonstrated that CPF-induced apoptosis was involved in mitochondrial dysfunction through the production of ROS. In the response of cellular antioxidant systems to CPF, we found that CPF treatment increased HO-1 expression while the expression of CuZnSOD and MnSOD was reduced. In addition, we found that CPF treatment activated MAPK pathways, including ERK 1/2, the JNK, and the p38 MAP kinase in a time-dependent manner. NAC treatment abolished MAPK phosphorylation caused by CPF, indicating that ROS are upstream signals of MAPK. Interestingly, MAPK inhibitors abolished cytotoxicity and reduced ROS generation by CPF treatment. Our results demonstrate that CPF induced neuronal cell death in part through MAPK activation via ROS generation, suggesting its potential to generate oxidative stress via mitochondrial damage and its involvement in oxidative stress-related neurodegenerative disease. -- Highlights: ► Chlorpyrifos induces apoptosis. ► Chlorpyrifos inhibits mitochondrial complex I activity. ► ROS is involved in chlorpyrifos-induced apoptosis. ► Chlorpyrifos affects cellular antioxidant systems. ► Chlorpyrifos-induced apoptosis mediates activation of MAPK.

  19. 75 FR 26225 - Frequency Regulation Compensation in the Organized Wholesale Power Markets; Notice of Technical...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-11

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Frequency Regulation Compensation in the Organized Wholesale Power Markets... conference to elicit input on issues pertaining to Frequency Regulation Compensation in the ISO/RTO...

  20. MuRF1 activity is present in cardiac mitochondria and regulates reactive oxygen species production in vivo.

    PubMed

    Mattox, Taylor A; Young, Martin E; Rubel, Carrie E; Spaniel, Carolyn; Rodríguez, Jessica E; Grevengoed, Trisha J; Gautel, Mathias; Xu, Zhelong; Anderson, Ethan J; Willis, Monte S

    2014-06-01

    MuRF1 is a previously reported ubiquitin-ligase found in striated muscle that targets troponin I and myosin heavy chain for degradation. While MuRF1 has been reported to interact with mitochondrial substrates in yeast two-hybrid studies, no studies have identified MuRF1's role in regulating mitochondrial function to date. In the present study, we measured cardiac mitochondrial function from isolated permeabilized muscle fibers in previously phenotyped MuRF1 transgenic and MuRF1-/- mouse models to determine the role of MuRF1 in intermediate energy metabolism and ROS production. We identified a significant decrease in reactive oxygen species production in cardiac muscle fibers from MuRF1 transgenic mice with increased α-MHC driven MuRF1 expression. Increased MuRF1 expression in ex vivo and in vitro experiments revealed no alterations in the respiratory chain complex I and II function. Working perfusion experiments on MuRF1 transgenic hearts demonstrated significant changes in glucose oxidation. However, total oxygen consumption was decreased [corrected]. This data provides evidence for MuRF1 as a novel regulator of cardiac ROS, offering another mechanism by which increased MuRF1 expression may be cardioprotective in ischemia reperfusion injury, in addition to its inhibition of apoptosis via proteasome-mediate degradation of c-Jun. The lack of mitochondrial function phenotype identified in MuRF1-/- hearts may be due to the overlapping interactions of MuRF1 and MuRF2 with energy regulating proteins found by yeast two-hybrid studies reported here, implying a duplicity in MuRF1 and MuRF2's regulation of mitochondrial function.

  1. MuRF1 activity is present in cardiac mitochondria and regulates reactive oxygen species production in vivo

    PubMed Central

    Mattox, Taylor A.; Young, Martin E.; Rubel, Carrie E.; Spaniel, Carolyn; Rodríguez, Jessica E.; Grevengoed, Trisha J.; Gautel, Mathias; Xu, Zhelong; Anderson, Ethan J.; Willis, Monte S.

    2014-01-01

    MuRF1 is a previously reported ubiquitin-ligase found in striated muscle that targets troponin I and myosin heavy chain for degradation. While MuRF1 has been reported to interact with mitochondrial substrates in yeast two-hybrid studies, no studies have identified MuRF1’s role in regulating mitochondrial function to date. In the present study, we measured cardiac mitochondrial function from isolated permeabilized muscle fibers in previously phenotyped MuRF1 transgenic and MuRF1−/− mouse models to determine the role of MuRF1 in intermediate energy metabolism and ROS production. We identified a significant decrease in reactive oxygen species production in cardiac muscle fibers from MuRF1 transgenic mice with increased alpha-MHC driven MuRF1 expression. Increased MuRF1 expression in ex vivo and in vitro experiments revealed no alterations in the respiratory chain complex I and II function. Working perfusion experiments on MuRF1 transgenic hearts demonstrated significant changes in glucose or oleate oxidation; however, total oxygen consumption was decreased. This data provides evidence for MuRF1 as a novel regulator of cardiac ROS, offering another mechanism by which increased MuRF1 expression may be cardioprotective in ischemia reperfusion injury, in addition to its inhibition of apoptosis via proteasome-mediate degradation of c-Jun. The lack of mitochondrial function phenotype identified in MuRF1−/− hearts may be due to the overlapping interactions of MuRF1 and MuRF2 with energy regulating proteins found by yeast two-hybrid studies reported here, implying a duplicity in MuRF1 and MuRF2’s regulation of mitochondrial function. PMID:24733503

  2. Engineering model of the electric drives of separation device for simulation of automatic control systems of reactive power compensation by means of serially connected capacitors

    NASA Astrophysics Data System (ADS)

    Juromskiy, V. M.

    2016-09-01

    It is developed a mathematical model for an electric drive of high-speed separation device in terms of the modeling dynamic systems Simulink, MATLAB. The model is focused on the study of the automatic control systems of the power factor (Cosφ) of an actuator by compensating the reactive component of the total power by switching a capacitor bank in series with the actuator. The model is based on the methodology of the structural modeling of dynamic processes.

  3. Using Self-regulation to Successfully Overcome the Negotiation Disadvantage of Low Power

    PubMed Central

    Jäger, Andreas; Loschelder, David D.; Friese, Malte

    2017-01-01

    A plethora of studies has demonstrated that low-power negotiators attain lower outcomes compared to high-power negotiators. We argue that this low-power disadvantage can be conceptualized as impaired goal attainment and that self-regulation can help to overcome it. Three experiments tested this assertion. In Study 1, low-power negotiators attained lower profits compared to their high-power opponents in a face-to-face negotiation. Negotiators who set themselves goals and those who additionally formed if-then plans prior to the negotiation overcame the low-power disadvantage. Studies 2 and 3 replicated these effects in computer-mediated negotiations: Low-power negotiators conceded more than high-power negotiators. Again, setting goals and forming additional if-then plans helped to counter the power disadvantage. Process analyses revealed that negotiators’ concession-making at the start of the negotiation mediated both the low-power disadvantage and the beneficial effects of self-regulation. The present findings show how the low-power disadvantage unfolds in negotiations and how self-regulatory techniques can help to overcome it. PMID:28382005

  4. Flow Regulator Powered by the Stalk of Vorticella convarallia

    NASA Astrophysics Data System (ADS)

    Matsumoto, N.; Nagai, M.; Hayasaka, Y.; Oguri, M.; Kawashima, T.; Shibata, T.

    2012-03-01

    We propose flow regulation by the stalk of Vorticella convarallia. The motion of stalk can be controlled by introducing Ca2+ and chelator solutions alternatively. The fluid channel is narrowed by fully extended V. convarallia, which results in increasing fluidic resistance and reducing flow rate. The flow regulator consists of a microchannel and Vorticella. The microchannel has two layers. The top layer contains a fluid channel where Vorticella is stored to control the flow rate. The bottom layer includes a control channel which enables control of the fluid channel by an external compressed air supply. After cells were introduced to the device at 1.0×103 cells/μL, eight of 18 chambers contained more than a single cell. Four cells of Vorticella were cultured in one chamber at a maximum. The cells were alive for two days after the injection. We evaluated the change in mean flow rate through the fluidic channel. The flow rate without V. convarallia increased linearly from 5.5nL/min to 1.1μL/min with applied pressure from 4 to 18kPa. The switching time of solutions measured two seconds at 10 kPa. The response time for the device was estimated to be approximately four seconds after the partial removal of cell membrane.

  5. Real power regulation for the utility power grid via responsive loads

    DOEpatents

    McIntyre, Timothy J [Knoxville, TN; Kirby, Brendan J [Knoxville, TN; Kisner, Roger A

    2009-05-19

    A system for dynamically managing an electrical power system that determines measures of performance and control criteria for the electric power system, collects at least one automatic generation control (AGC) input parameter to at least one AGC module and at least one automatic load control (ALC) input parameter to at least one ALC module, calculates AGC control signals and loads as resources (LAR) control signals in response to said measures of performance and control criteria, propagates AGC control signals to power generating units in response to control logic in AGC modules, and propagates LAR control signals to at least one LAR in response to control logic in ALC modules.

  6. Hyperosmotic stress-dependent NFkappaB activation is regulated by reactive oxygen species and IGF-1 in cultured cardiomyocytes.

    PubMed

    Eisner, Verónica; Criollo, Alfredo; Quiroga, Clara; Olea-Azar, Claudio; Santibañez, Juan Francisco; Troncoso, Rodrigo; Chiong, Mario; Díaz-Araya, Guillermo; Foncea, Rocío; Lavandero, Sergio

    2006-08-07

    We have recently shown that hyperosmotic stress activates p65/RelB NFkappaB in cultured cardiomyocytes with dichotomic actions on caspase activation and cell death. It remains unexplored how NFkappaB is regulated in cultured rat cardiomyocytes exposed to hyperosmotic stress. We study here: (a) if hyperosmotic stress triggers reactive oxygen species (ROS) generation and in turn whether they regulate NFkappaB and (b) if insulin-like growth factor-1 (IGF-1) modulates ROS production and NFkappaB activation in hyperosmotically-stressed cardiomyocytes. The results showed that hyperosmotic stress generated ROS in cultured cardiac myocytes, in particular the hydroxyl and superoxide species, which were inhibited by N-acetylcysteine (NAC). Hyperosmotic stress-induced NFkappaB activation as determined by IkappaBalpha degradation and NFkappaB DNA binding. NFkappaB activation and procaspase-3 and -9 fragmentation were prevented by NAC and IGF-1. However, this growth factor did not decrease ROS generation induced by hyperosmotic stress, suggesting that its actions over NFkappaB and caspase activation may be due to modulation of events downstream of ROS generation. We conclude that hyperosmotic stress induces ROS, which in turn activates NFkappaB and caspases. IGF-1 prevents NFkappaB activation by a ROS-independent mechanism.

  7. Emotion reactivity and regulation are associated with psychological functioning following the 2011 earthquake, tsunami, and nuclear crisis in Japan.

    PubMed

    Cavanagh, Sarah R; Fitzgerald, Erin J; Urry, Heather L

    2014-04-01

    Frequent and successful use of cognitive reappraisal, an emotion regulation strategy that involves rethinking the meaning of an emotional event in order to change one's emotional response, has been linked in everyday life to positive outcomes such as higher well-being. Whether we should expect this association to be maintained in a strong, temporally and spatially close emotional context is an unexplored question that might have important implications for our understanding of emotion regulation and its relations to psychological functioning. In this study of members of the U. S. Embassy Tokyo community in the months following the March 2011 earthquake, tsunami, and nuclear crisis in Japan, self-reported use of cognitive reappraisal was not related to psychological functioning, but demonstrated success using cognitive reappraisal to decrease feelings of unpleasantness in response to disaster-related pictures on a performance-based task was associated with fewer symptoms of depression and posttraumatic stress. Moreover, emotional reactivity to these pictures was associated with greater symptomatology. These results suggest that situational intensity may be an important moderator of reappraisal and psychological functioning relationships.

  8. [The significance of stress intensity for the emotional and visceral reactivity, especially for blood pressure regulation].

    PubMed

    Hecht, K; Hai, N V; Moritz, V; Hecht, T

    1976-01-01

    The influence of light, medium, and heavy chronic stress upon cerebro-visceral functions following 3 and 5 weeks of daily stress exposure was examined. The following results were obtained: Light stress produced no changes of cerebro-visceral functions. Medium stress restricted the learning and memory capacity, increased systolic blood pressure, fasting blood sugar and adrenal weights. The B-cells of the pancreatic islets showed degranulations of varying intensity. Heavy stress diminished the learning and memory capacity, increased adrenal weights and led to hypergranulation of the pancreatic B-cells. Blood sugar and blood pressure values fall within physiological limits. Load tests, however, revealed in these animals symptoms of premorbid states. Since throughout the period of observation, light stress stablized the regulation processes, medium stress induced early stages of pathological processes, and heavy stress caused premorbid states, no linearity could be established between the load intensity and the changes of cerebro-visceral functions.

  9. Modeling and Performance Improvement of the Constant Power Regulator Systems in Variable Displacement Axial Piston Pump

    PubMed Central

    Park, Sung Hwan; Lee, Ji Min; Kim, Jong Shik

    2013-01-01

    An irregular performance of a mechanical-type constant power regulator is considered. In order to find the cause of an irregular discharge flow at the cut-off pressure area, modeling and numerical simulations are performed to observe dynamic behavior of internal parts of the constant power regulator system for a swashplate-type axial piston pump. The commercial numerical simulation software AMESim is applied to model the mechanical-type regulator with hydraulic pump and simulate the performance of it. The validity of the simulation model of the constant power regulator system is verified by comparing simulation results with experiments. In order to find the cause of the irregular performance of the mechanical-type constant power regulator system, the behavior of main components such as the spool, sleeve, and counterbalance piston is investigated using computer simulation. The shape modification of the counterbalance piston is proposed to improve the undesirable performance of the mechanical-type constant power regulator. The performance improvement is verified by computer simulation using AMESim software. PMID:24282389

  10. Modeling and performance improvement of the constant power regulator systems in variable displacement axial piston pump.

    PubMed

    Park, Sung Hwan; Lee, Ji Min; Kim, Jong Shik

    2013-01-01

    An irregular performance of a mechanical-type constant power regulator is considered. In order to find the cause of an irregular discharge flow at the cut-off pressure area, modeling and numerical simulations are performed to observe dynamic behavior of internal parts of the constant power regulator system for a swashplate-type axial piston pump. The commercial numerical simulation software AMESim is applied to model the mechanical-type regulator with hydraulic pump and simulate the performance of it. The validity of the simulation model of the constant power regulator system is verified by comparing simulation results with experiments. In order to find the cause of the irregular performance of the mechanical-type constant power regulator system, the behavior of main components such as the spool, sleeve, and counterbalance piston is investigated using computer simulation. The shape modification of the counterbalance piston is proposed to improve the undesirable performance of the mechanical-type constant power regulator. The performance improvement is verified by computer simulation using AMESim software.

  11. A transdiagnostic approach to examining the incremental predictive power of emotion regulation and basic personality dimensions.

    PubMed

    Stanton, Kasey; Rozek, David C; Stasik-O'Brien, Sara M; Ellickson-Larew, Stephanie; Watson, David

    2016-10-01

    Although personality and emotion regulation abilities appear to overlap considerably, few studies have adopted an integrative approach by examining personality and emotion regulation together. Therefore, it is unclear how much incremental power emotion regulation demonstrates in predicting psychopathology beyond personality traits, and vice versa. Results from a community sample characterized by high levels of psychopathology (N = 299) indicated that personality and emotion regulation represent strongly related but distinguishable constructs, with both showing incremental power beyond the other in many cases in predicting self-reported and interview-rated psychopathology. More specifically, difficulties in responding adaptively to negative emotional experiences displayed predictive power beyond neuroticism and other personality traits in predicting internalizing psychopathology and psychoticism. Conversely, neuroticism displayed substantial incremental predictive power beyond emotion regulation and other five-factor model traits, especially for anxiety and other internalizing psychopathology. Other five-factor model traits also showed incremental predictive power in specific cases (e.g., agreeableness and conscientiousness showed specificity in predicting antagonism and disinhibition, respectively). These data provide a starting point for developing a finer-grained understanding of how emotion dysregulation and personality traits are implicated in a range of psychopathology, highlighting the value of adopting an integrative approach of examining emotion regulation and personality traits concurrently. (PsycINFO Database Record

  12. Rho kinase acts as a downstream molecule to participate in protein kinase Cε regulation of vascular reactivity after hemorrhagic shock in rats.

    PubMed

    Li, Tao; Zhu, Yu; Zang, Jia-tao; Peng, Xiao-yong; Lan, Dan; Yang, Guang-ming; Xu, Jing; Liu, Liang-ming

    2014-09-01

    Our previous study demonstrated that Rho kinase and protein kinase C (PKC) played important parts in the regulation of vascular reactivity after shock. Using superior mesenteric arteries (SMAs) from hemorrhagic shock rats and hypoxia-treated vascular smooth muscle cells (VSMCs), relationship of PKCε regulation of vascular reactivity to Rho kinase, as well as the signal transduction after shock, was investigated. The results showed that inhibition of Rho kinase with the Rho kinase-specific inhibitor Y-27632 antagonized the PKCε-specific agonist carbachol and highly expressed PKCε-induced increase of vascular reactivity in SMAs and VSMCs, whereas inhibition of PKCε with its specific inhibitory peptide did not antagonize the Rho kinase agonist (U-46619)-induced increase of vascular reactivity in SMAs and VSMCs. Activation of PKCε or highly expressed PKCε upregulated the activity of Rho kinase and the phosphorylation of PKC-dependent phosphatase inhibitor 17 (CPI-17), zipper interacting protein kinase (ZIPK), and integrin-linked kinase (ILK), whereas activation of Rho kinase increased only CPI-17 phosphorylation. The specific neutralization antibodies of ZIPK and ILK antagonized PKCε-induced increases in the activity of Rho kinase, but CPI-17 neutralization antibody did not antagonize this effect. These results suggested that Rho kinase takes part in the regulation of PKCε on vascular reactivity after shock. Rho kinase is downstream of PKCε. Protein kinase Cε activates Rho kinase via ZIPK and ILK; CPI-17 is downstream of Rho kinase.

  13. Epithelial, Dendritic, and CD4+ T Cell Regulation of and by Reactive Oxygen and Nitrogen Species in Allergic Sensitization

    PubMed Central

    Ckless, Karina; Hodgkins, Samantha R.; Ather, Jennifer L.; Martin, Rebecca; Poynter, Matthew E.

    2011-01-01

    Background While many of the contributing cell types and mediators of allergic asthma are known, less well understood are the factors that induce allergy in the first place. Amongst the mediators speculated to affect initial allergen sensitization and the development of pathogenic allergic responses to innocuous inhaled antigens and allergens are exogenously- or endogenously-generated reactive oxygen species (ROS) and reactive nitrogen species (RNS). Scope of Review The interactions between ROS/RNS, dendritic cells (DCs), and CD4+ T cells, as well as their modulation by lung epithelium, are of critical importance for the genesis of allergies that later manifest in allergic asthma. Therefore, this review will primarily focus on the initiation of pulmonary allergies and the role that ROS/RNS may play in the steps therein, using examples from our own work on the roles of NO2 exposure and airway epithelial NF-κB activation. Major Conclusions Endogenously-generated ROS/RNS and those encountered from environmental sources interact with epithelium, DCs, and CD4+ T cells to orchestrate allergic sensitization through modulation of the activities of each of these cell types, which quatitiatively and qualitatively dictate the degree and type of the allergic asthma phenotype. General Significance Knowledge of the effects of ROS/RNS at the molecular and cellular levels has the potential to provide powerful insight into the balance between inhalational tolerance (the typical immunologic response to an innocuous inhaled antigen) and allergy, as well as to potentially provide mechanistic targets for the prevention and treatment of asthma. PMID:21397661

  14. Child Maltreatment, Inflammation, and Internalizing Symptoms: Investigating the Roles of C-Reactive Protein, Gene Variation and Neuroendocrine Regulation

    PubMed Central

    Cicchetti, Dante; Handley, Elizabeth D.; Rogosch, Fred A.

    2015-01-01

    Prior research has found inconsistent evidence regarding the association among childhood adversity, inflammation, and internalizing symptoms, perhaps because previous studies have yet to adequately integrate important factors such as the timing of the adversity, genetic variation, and other relevant processes such as neuroendocrine regulation. The aims of the present study were threefold: 1) Determine whether the effect of the timing of child maltreatment on C-reactive protein (CRP), an inflammatory marker, varies by CRP gene variation; 2) Explore whether links between salivary CRP and childhood internalizing symptoms depend on the presence and timing of maltreatment experiences; 3) Investigate the role of CRP in the relations between child neuroendocrine regulation and internalizing symptoms and examine whether these associations are moderated by the presence and timing of child maltreatment. Participants included a sample of 267 maltreated and 222 nonmaltreated children (M age= 9.72, SD=0.99; 52.4% male; 66% African-American) who attended a summer day camp research program designed for school-aged low-income children. Department of Human Services records were examined to determine the onset and recency of maltreatment for children in the maltreated group. Results indicated that among children with recent onset maltreatment, those with at least one A allele from CRP SNP rs1417938 evidenced significantly higher CRP levels compared to recently maltreated children carrying the TT genotype. Moreover, higher levels of CRP were associated with higher levels of internalizing symptoms only for recently maltreated children. Finally, we did not find support for salivary CRP as a mechanism in the relation between neuroendocrine regulation and childhood internalizing symptoms. Our findings highlight the importance of the timing of child maltreatment and have important implications for characterizing variability in inflammation and internalizing symptoms among youth. PMID

  15. Child maltreatment, inflammation, and internalizing symptoms: Investigating the roles of C-reactive protein, gene variation, and neuroendocrine regulation.

    PubMed

    Cicchetti, Dante; Handley, Elizabeth D; Rogosch, Fred A

    2015-05-01

    Prior research has found inconsistent evidence regarding the association among childhood adversity, inflammation, and internalizing symptoms, perhaps because previous studies have yet to adequately integrate important factors such as the timing of the adversity, genetic variation, and other relevant processes such as neuroendocrine regulation. The aims of the present study were threefold: (a) to determine whether the effect of the timing of child maltreatment on C-reactive protein (CRP), an inflammatory marker, varies by CRP gene variation; (b) to explore whether links between salivary CRP and childhood internalizing symptoms depend on the presence and timing of maltreatment experiences; and (c) to investigate the role of CRP in the relations between child neuroendocrine regulation and internalizing symptoms and examine whether these associations are moderated by the presence and timing of child maltreatment. Participants included a sample of 267 maltreated and 222 nonmaltreated children (M age = 9.72, SD = 0.99; 52.4% male; 66% African American) who attended a summer day camp research program designed for school-aged low-income children. Department of Human Services records were examined to determine the onset and recency of maltreatment for children in the maltreated group. The results indicated that among children with recent onset maltreatment, those with at least one A allele from CRP single nucleotide polymorphism rs1417938 evidenced significantly higher CRP levels compared to recently maltreated children carrying the TT genotype. Moreover, higher levels of CRP were associated with higher levels of internalizing symptoms only for recently maltreated children. Finally, we did not find support for salivary CRP as a mechanism in the relation between neuroendocrine regulation and childhood internalizing symptoms. Our findings highlight the importance of the timing of child maltreatment and have important implications for characterizing variability in inflammation

  16. Selective Capture of CWAs and Containment of Their Neutralization Byproducts by Porous Frameworks Presenting Self-Amplifying and Self-Regulating Reactivities

    DTIC Science & Technology

    2013-02-04

    Schmidt Lectureship, Weizmann Institute, Israel 2007 Materials Research Society, MRS Medal Sole Recipient 2007 Deans Recognition Award, UCLA...display self-propagating and self-regulating reactivities toward chemical war- fare agents (CWAs). Our research objective is to use functionalizable... recognition events into rapid and reversible colorimetric response that can readily be detected without resorting to elaborate optical devices. Unlike

  17. Early Activation of STAT3 Regulates Reactive Astrogliosis Induced by Diverse Forms of Neurotoxicity

    PubMed Central

    O'Callaghan, James P.; Kelly, Kimberly A.; VanGilder, Reyna L.; Sofroniew, Michael V.; Miller, Diane B.

    2014-01-01

    Astrogliosis, a cellular response characterized by astrocytic hypertrophy and accumulation of GFAP, is a hallmark of all types of central nervous system (CNS) injuries. Potential signaling mechanisms driving the conversion of astrocytes into “reactive” phenotypes differ with respect to the injury models employed and can be complicated by factors such as disruption of the blood-brain barrier (BBB). As denervation tools, neurotoxicants have the advantage of selective targeting of brain regions and cell types, often with sparing of the BBB. Previously, we found that neuroinflammation and activation of the JAK2-STAT3 pathway in astrocytes precedes up regulation of GFAP in the MPTP mouse model of dopaminergic neurotoxicity. Here we show that multiple mechanistically distinct mouse models of neurotoxicity (MPTP, AMP, METH, MDA, MDMA, KA, TMT) engender the same neuroinflammatory and STAT3 activation responses in specific regions of the brain targeted by each neurotoxicant. The STAT3 effects seen for TMT in the mouse could be generalized to the rat, demonstrating cross-species validity for STAT3 activation. Pharmacological antagonists of the neurotoxic effects blocked neuroinflammatory responses, pSTAT3tyr705 and GFAP induction, indicating that damage to neuronal targets instigated astrogliosis. Selective deletion of STAT3 from astrocytes in STAT3 conditional knockout mice markedly attenuated MPTP-induced astrogliosis. Monitoring STAT3 translocation in GFAP-positive cells indicated that effects of MPTP, METH and KA on pSTAT3tyr705 were localized to astrocytes. These findings strongly implicate the STAT3 pathway in astrocytes as a broadly triggered signaling pathway for astrogliosis. We also observed, however, that the acute neuroinflammatory response to the known inflammogen, LPS, can activate STAT3 in CNS tissue without inducing classical signs of astrogliosis. Thus, acute phase neuroinflammatory responses and neurotoxicity-induced astrogliosis both signal through

  18. Wind-powered asynchronous AC/DC/AC converter system. [for electric power supply regulation

    NASA Technical Reports Server (NTRS)

    Reitan, D. K.

    1973-01-01

    Two asynchronous ac/dc/ac systems are modelled that utilize wind power to drive a variable or constant hertz alternator. The first system employs a high power 60-hertz inverter tie to the large backup supply of the power company to either supplement them from wind energy, storage, or from a combination of both at a preset desired current; rectifier and inverter are identical and operate in either mode depending on the silicon control rectifier firing angle. The second system employs the same rectification but from a 60-hertz alternator arrangement; it provides mainly dc output, some sinusoidal 60-hertz from the wind bus and some high harmonic content 60-hertz from an 800-watt inverter.

  19. Problems of standardizing and technical regulation in the electric power industry

    NASA Astrophysics Data System (ADS)

    Grabchak, E. P.

    2016-12-01

    A mandatory condition to ensure normal operation of a power system and efficiency in the sector is standardization and legal regulation of technological activities of electric power engineering entities and consumers. Compared to the times of USSR, the present-time technical guidance documents are not mandatory to follow in most cases, being of an advisory nature due to the lack of new ones. During the last five years, the industry has been showing a deterioration of the situation in terms of ensuring reliability and engineering controllability as a result of the dominant impact of short-term market stimuli and the differences in basic technological policies. In absence of clear requirements regarding the engineering aspects of such activities, production operation does not contribute to the preserving of technical integrity of the Russian power system, which leads to the loss of performance capability and controllability and causes disturbances in the power supply to consumers. The result of this problem is a high rate of accident incidence. The dynamics of accidents by the type of equipment is given, indicating a persisting trend of growth in the number of accidents, which are of a systematic nature. Several problematic aspects of engineering activities of electric power engineering entities, requiring standardization and legal regulation are pointed out: in the domestic power system, a large number of power electrotechnical and generating equipment operate along with systems of regulation, which do not comply with the principles and technical rules representing a framework where the Energy System of Russia is built and functioning

  20. Electric power: contemporary issues and the federal role in oversight and regulation

    SciTech Connect

    Not Available

    1981-12-21

    Electric power will play an important role in the Nation's energy picture, but rapidly increasing fuel prices, lower growth rates, and difficulties in developing large powerplants have made it difficult for electric utilities to provide adequate supplies of power at prices the public is willing to pay. This report provides the Congress with a discussion of: important issues in electric power regulation and management, recent GAO reports on some of those issues, and questions and observations about power system planning and development which deserve Federal attention. It specifically highlights important electric power issues which transcend State, regional, and utility decisionmaking and identifies for the Congress significant areas which should be considered when making decisions affecting the electric power industry.

  1. The global regulator ArcA controls resistance to reactive nitrogen and oxygen intermediates in Salmonella enterica serovar Enteritidis.

    PubMed

    Lu, Sangwei; Killoran, Patrick B; Fang, Ferric C; Riley, Lee W

    2002-02-01

    Salmonella enterica serovar Enteritidis is a major cause of food-borne diseases associated with consumption of shell eggs. Clinical isolates of S. enterica serovar Enteritidis exhibit a wide spectrum of virulence in mice. A highly virulent isolate (SE2472) was previously shown to be more resistant in vitro than other clinical isolates to acidified sodium nitrite (ASN), a generator of reactive nitrogen and oxygen intermediates (RNI/ROI). SE2472 is also more resistant to S-nitrosoglutathione (GSNO) and hydrogen peroxide (H(2)O(2)) than an ASN-susceptible isolate of S. enterica serovar Enteritidis (SE8743). To investigate the molecular basis for the RNI/ROI resistance of S. enterica serovar Enteritidis, we transformed a genomic DNA library of SE2472 into SE8743. A plasmid clone conferred upon SE8743 enhanced resistance to ASN, GSNO, and H(2)O(2). The DNA insert in the clone encoded ArcA, a global regulator. An arcA mutant of SE2472 was constructed and was found to be more susceptible to GSNO and hydrogen peroxide but not more susceptible to ASN than wild-type SE2472. The susceptibility of the arcA mutant to GSNO and H(2)O(2) was complemented by a plasmid harboring arcA. The coding sequence of the arcA gene in SE2472 and the coding sequence of the arcA gene in SE8743 were identical, suggesting that the difference in resistance to RNI/ROI maybe due to the activity of genes regulated by ArcA. No significant difference in virulence between the wild type and the arcA mutant of SE2472 was observed in mice. These observations show that arcA is essential for resistance of S. enterica serovar Enteritidis to nitrosative and oxidative stress. However, additional genetic loci may contribute to the resistance to RNI/ROI and unusually high virulence for mice of SE2472.

  2. Amyloid-β-induced reactive oxygen species production and priming are differentially regulated by ion channels in microglia.

    PubMed

    Schilling, Tom; Eder, Claudia

    2011-12-01

    Production of reactive oxygen species (ROS) by microglial cells and subsequent oxidative stress are strongly implicated in the pathogenesis of Alzheimer's disease. Although it is recognized that amyloid-β (Aβ) plays a major role in inducing and regulating microglial ROS production in Alzheimer's disease, to date little is known about cellular mechanisms underlying Aβ-stimulated ROS production. Here, we identified ion channels involved in Aβ-induced microglial ROS production and in Aβ-induced microglial priming. Acute stimulation of microglial cells with either fibrillar Aβ(1-42) (fAβ(1-42) ) or soluble Aβ(1-42) (sAβ(1-42) ) caused significant increases in microglial ROS production, which were abolished by inhibition of TRPV1 cation channels with 5-iodo-resiniferatoxin (I-RTX), but were unaffected by inhibition of K(+) channels with charybdotoxin (CTX). Furthermore, pretreatment with either fAβ(1-42) or sAβ(1-42) induced microglial priming, that is, increased ROS production upon secondary stimulation with the phorbol ester PMA. Microglial priming induced by fAβ(1-42) or sAβ(1-42) remained unaffected by TRPV1 channel inhibition with I-RTX. However, sAβ(1-42) -induced priming was inhibited by CTX and margatoxin, but not by TRAM-34 or paxilline, indicating a role of Kv1.3 voltage-gated K(+) channels, but not of Ca(2+) -activated K(+) channels, in the priming process. In summary, our data suggest that in microglia Aβ-induced ROS production and priming are differentially regulated by ion channels, and that TRPV1 cation channels and Kv1.3 K(+) channels may provide potential therapeutic targets to reduce microglia-induced oxidative stress in Alzheimer's disease.

  3. β-Cell Uncoupling Protein 2 Regulates Reactive Oxygen Species Production, Which Influences Both Insulin and Glucagon Secretion

    PubMed Central

    Robson-Doucette, Christine A.; Sultan, Sobia; Allister, Emma M.; Wikstrom, Jakob D.; Koshkin, Vasilij; Bhatacharjee, Alpana; Prentice, Kacey J.; Sereda, Samuel B.; Shirihai, Orian S.; Wheeler, Michael B.

    2011-01-01

    OBJECTIVE The role of uncoupling protein 2 (UCP2) in pancreatic β-cells is highly debated, partly because of the broad tissue distribution of UCP2 and thus limitations of whole-body UCP2 knockout mouse models. To investigate the function of UCP2 in the β-cell, β-cell–specific UCP2 knockout mice (UCP2BKO) were generated and characterized. RESEARCH DESIGN AND METHODS UCP2BKO mice were generated by crossing loxUCP2 mice with mice expressing rat insulin promoter-driven Cre recombinase. Several in vitro and in vivo parameters were measured, including respiration rate, mitochondrial membrane potential, islet ATP content, reactive oxygen species (ROS) levels, glucose-stimulated insulin secretion (GSIS), glucagon secretion, glucose and insulin tolerance, and plasma hormone levels. RESULTS UCP2BKO β-cells displayed mildly increased glucose-induced mitochondrial membrane hyperpolarization but unchanged rates of uncoupled respiration and islet ATP content. UCP2BKO islets had elevated intracellular ROS levels that associated with enhanced GSIS. Surprisingly, UCP2BKO mice were glucose-intolerant, showing greater α-cell area, higher islet glucagon content, and aberrant ROS-dependent glucagon secretion under high glucose conditions. CONCLUSIONS Using a novel β-cell–specific UCP2KO mouse model, we have shed light on UCP2 function in primary β-cells. UCP2 does not behave as a classical metabolic uncoupler in the β-cell, but has a more prominent role in the regulation of intracellular ROS levels that contribute to GSIS amplification. In addition, β-cell UCP2 contributes to the regulation of intraislet ROS signals that mediate changes in α-cell morphology and glucagon secretion. PMID:21984579

  4. Potential role of reactive oxygen species and antioxidant genes in the regulation of peach fruit development and ripening.

    PubMed

    Huan, Chen; Jiang, Li; An, Xiujuan; Yu, Mingliang; Xu, Yin; Ma, Ruijuan; Yu, Zhifang

    2016-07-01

    The roles of reactive oxygen species (ROS) as both toxic by-products and as signaling molecules have been reported in fruit development and ripening. Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) play important roles in balancing the induction and removal of ROS in plants, and are respectively encoded by families of closely homologous genes. In the present study, we investigated the roles of ROS and the above-mentioned antioxidant genes during the development and ripening of peach fruit. The experimental results indicated that O2(-) and H2O2 acted as potential signaling molecules in the middle stage of fruit development, and only H2O2 might function as a main toxic molecule to stimulate lipid peroxidation and oxidative stress in the late stage of fruit ripening. PpaCu/Zn-SODs were the most abundant members in the PpaSOD gene family and they expressed steadily in peach fruit development and ripening. Low temperature (4 °C) postponed and suppressed the climacteric peaks of respiration and ethylene, significantly enhanced the activities of CAT and GPX, and up-regulated the expression of PpaCAT1 and PpaGPX6 in the late stage of fruit ripening. PpaCAT1 and PpaGPX6 were two key genes in alleviating oxidative stress in the late stage of fruit ripening.

  5. RNH1 regulation of reactive oxygen species contributes to histone deacetylase inhibitor resistance in gastric cancer cells.

    PubMed

    Zhu, Y; Das, K; Wu, J; Lee, M H; Tan, P

    2014-03-20

    Histone deacetylase inhibitors (HDACis) are a promising class of anticancer epigenetic drugs, however, molecular factors influencing the responses of individual tumors to HDACi therapies remain obscure. Here, we sought to identify genes associated with HDACi resistance in gastric cancer. Treating a panel of 17 gastric cancer cell lines with multiple HDACi compounds (trichostatin A, SAHA and MS275), we identified two distinct classes of lines exhibiting either HDACi sensitivity or resistance. Genomic comparisons between the sensitive and resistant classes using two independent microarray platforms identified RNH1, encoding a ribonuclease inhibitor, as a gene highly expressed in HDACi-resistant lines. Using genetic knockdown and overexpression assays, we show that RNH1 is both necessary and sufficient to induce HDACi resistance, and that RNH1 is likely to mediate this resistance through the dampening of HDACi-induced reactive oxygen species (ROS) in cancer cells. The discovery of RNH1 as a regulator of HDACi resistance in gastric cancer highlights a functional role for ROS induction in the cellular effects of this important drug class.

  6. Temporal-Spatial Interaction between Reactive Oxygen Species and Abscisic Acid Regulates Rapid Systemic Acclimation in Plants[W][OPEN

    PubMed Central

    Suzuki, Nobuhiro; Miller, Gad; Salazar, Carolina; Mondal, Hossain A.; Shulaev, Elena; Cortes, Diego F.; Shuman, Joel L.; Luo, Xiaozhong; Shah, Jyoti; Schlauch, Karen; Shulaev, Vladimir; Mittler, Ron

    2013-01-01

    Being sessile organisms, plants evolved sophisticated acclimation mechanisms to cope with abiotic challenges in their environment. These are activated at the initial site of exposure to stress, as well as in systemic tissues that have not been subjected to stress (termed systemic acquired acclimation [SAA]). Although SAA is thought to play a key role in plant survival during stress, little is known about the signaling mechanisms underlying it. Here, we report that SAA in plants requires at least two different signals: an autopropagating wave of reactive oxygen species (ROS) that rapidly spreads from the initial site of exposure to the entire plant and a stress-specific signal that conveys abiotic stress specificity. We further demonstrate that SAA is stress specific and that a temporal–spatial interaction between ROS and abscisic acid regulates rapid SAA to heat stress in plants. In addition, we demonstrate that the rapid ROS signal is associated with the propagation of electric signals in Arabidopsis thaliana. Our findings unravel some of the basic signaling mechanisms underlying SAA in plants and reveal that signaling events and transcriptome and metabolome reprogramming of systemic tissues in response to abiotic stress occur at a much faster rate than previously envisioned. PMID:24038652

  7. Global regulation of reactive oxygen species scavenging genes in alfalfa root and shoot under gradual drought stress and recovery.

    PubMed

    Kang, Yun; Udvardi, Michael

    2012-05-01

    Reactive oxygen species (ROS) production and scavenging in plants under drought stress have been studied intensively in recent years. Here we report a global analysis of gene expression for the major ROS generating and scavenging proteins in alfalfa root and shoot under gradual drought stress followed by one-day recovery. Data from two alfalfa varieties, one drought tolerant and one drought sensitive, were compared and no qualitative differences in ROS gene regulation between the two were found. Conserved, tissue-specific patterns of gene expression in response to drought were observed for several ROS-scavenging gene families, including ascorbate peroxidase, monodehydroascorbate reductase, and peroxiredoxin. In addition, differential gene expression within families was observed. Genes for the ROS-generating enzyme, NADPH oxidase were generally induced under drought, while those for glycolate oxidase were repressed. Among the ROS-scavenging protein genes, Ferritin, Cu/Zn superoxide dismutase (SOD), and the majority of the glutathione peroxidase family members were induced under drought in both roots and shoots of both alfalfa varieties. In contrast, Fe-SOD, CC-type glutaredoxins, and thoiredoxins were downregulated.

  8. MLK3 is part of a feedback mechanism that regulates different cellular responses to reactive oxygen species.

    PubMed

    Lee, Ho-Sung; Hwang, Chae Young; Shin, Sung-Young; Kwon, Ki-Sun; Cho, Kwang-Hyun

    2014-06-03

    Reactive oxygen species (ROS) influence diverse cellular processes, including proliferation and apoptosis. Both endogenous and exogenous ROS activate signaling through mitogen-activated proteins kinase (MAPK) pathways, including those involving extracellular signal-regulated kinases (ERKs) or c-Jun N-terminal kinases (JNKs). Whereas low concentrations of ROS generally stimulate proliferation, high concentrations result in cell death. We found that low concentrations of ROS induced activating phosphorylation of ERKs, whereas high concentrations of ROS induced activating phosphorylation of JNKs. Mixed lineage kinase 3 (MLK3, also known as MAP3K11) directly phosphorylates JNKs and may control activation of ERKs. Mathematical modeling of MAPK networks revealed a positive feedback loop involving MLK3 that determined the relative phosphorylation of ERKs and JNKs by ROS. Cells exposed to an MLK3 inhibitor or cells in which MLK3 was knocked down showed increased activation of ERKs and decreased activation of JNKs and were resistant to cell death when exposed to high concentrations of ROS. Thus, the data indicated that MLK3 is a critical factor controlling the activity of kinase networks that control the cellular responses to different concentrations of ROS.

  9. Myeloid cell-derived reactive oxygen species externally regulate the proliferation of myeloid progenitors in emergency granulopoiesis

    PubMed Central

    Kwak, Hyun-Jeong; Liu, Peng; Bajrami, Besnik; Xu, Yuanfu; Park, Shin-Young; Nombela-Arrieta, Cesar; Mondal, Subhanjan; Sun, Yan; Zhu, Haiyan; Chai, Li; Silberstein, Leslie E.; Cheng, Tao; Luo, Hongbo R.

    2015-01-01

    Summary The cellular mechanisms controlling infection-induced emergency granulopoiesis are poorly defined. Here we found that reactive oxygen species (ROS) concentrations in the bone marrow (BM) were elevated during acute infection in a phagocytic NADPH oxidase-dependent manner in myeloid cells. Gr1+ myeloid cells were uniformly distributed in the BM, and all c-Kit+ progenitor cells were adjacent to Gr1+ myeloid cells. Inflammation-induced ROS production in the BM played a critical role in myeloid progenitor expansion during emergency granulopoiesis. ROS elicited oxidation and deactivation of phosphatase and tensin homolog (PTEN), resulting in up-regulation of PtdIns(3,4,5)P3 signaling in BM myeloid progenitors. We further revealed that BM myeloid cell-produced ROS stimulated proliferation of myeloid progenitors via a paracrine mechanism. Taken together, our results establish that phagocytic NADPH oxidase-mediated ROS production by BM myeloid cells plays a critical role in mediating emergency granulopoiesis during acute infection. PMID:25579427

  10. Mothers' depressive symptoms predict both increased and reduced negative reactivity: aversion sensitivity and the regulation of emotion.

    PubMed

    Dix, Theodore; Moed, Anat; Anderson, Edward R

    2014-07-01

    This study examined whether, as mothers' depressive symptoms increase, their expressions of negative emotion to children increasingly reflect aversion sensitivity and motivation to minimize ongoing stress or discomfort. In multiple interactions over 2 years, negative affect expressed by 319 mothers and their children was observed across variations in mothers' depressive symptoms, the aversiveness of children's immediate behavior, and observed differences in children's general negative reactivity. As expected, depressive symptoms predicted reduced maternal negative reactivity when child behavior was low in aversiveness, particularly with children who were high in negative reactivity. Depressive symptoms predicted high negative reactivity and steep increases in negative reactivity as the aversiveness of child behavior increased, particularly when high and continued aversiveness from the child was expected (i.e., children were high in negative reactivity). The findings are consistent with the proposal that deficits in parenting competence as depressive symptoms increase reflect aversion sensitivity and motivation to avoid conflict and suppress children's aversive behavior.

  11. Resveratrol regulates mitochondrial reactive oxygen species homeostasis through Sirt3 signaling pathway in human vascular endothelial cells

    PubMed Central

    Zhou, X; Chen, M; Zeng, X; Yang, J; Deng, H; Yi, L; Mi, M-t

    2014-01-01

    Mitochondrial reactive oxygen species (mtROS) homeostasis plays an essential role in preventing oxidative injury in endothelial cells, an initial step in atherogenesis. Resveratrol (RSV) possesses a variety of cardioprotective activities, however, little is known regarding the effects of RSV on mtROS homeostasis in endothelial cells. Sirt3 is a mitochondrial deacetylase, which plays a key role in mitochondrial bioenergetics and is closely associated with oxidative stress. The goal of the study is to investigate whether RSV could attenuate oxidative injury in endothelial cells via mtROS homeostasis regulation through Sirt3 signaling pathway. We found that pretreatment with RSV suppressed tert-butyl hydroperoxide (t-BHP)-induced oxidative damage in human umbilical vein endothelial cells (HUVECs) by increasing cell viability, inhibiting cell apoptosis, repressing collapse of mitochondrial membrane potential and decreasing mtROS generation. Moreover, the enzymatic activities of isocitrate dehydrogenase 2 (IDH2), glutathione peroxidase (GSH-Px) and manganese superoxide dismutase (SOD2) as well as deacetylation of SOD2 were increased by RSV pretreatment, suggesting RSV notably enhanced mtROS scavenging in t-BHP-induced endothelial cells. Meanwhile, RSV remarkably reduced mtROS generation by promoting Sirt3 enrichment within the mitochondria and subsequent upregulation of forkhead box O3A (FoxO3A)-mediated mitochondria-encoded gene expression of ATP6, CO1, Cytb, ND2 and ND5, thereby leading to increased complex I activity and ATP synthesis. Furthermore, RSV activated the expressions of phosphorylated adenosine monophosphate-activated protein kinase (p-AMPK), peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α) and Sirt3, as well as estrogen-related receptor-α (ERRα)-dependent Sirt3 mRNA transcription, which were abolished in the presence of AMPK inhibitor and AMPK, PGC-1α or Sirt3 siRNA transfection, indicating the effects of RSV on mt

  12. Application of simultaneous active and reactive power modulation of superconducting magnetic energy storage unit to damp turbine-generator subsynchronous oscillations

    SciTech Connect

    Wu, Chijui; Lee, Yuangshung )

    1993-03-01

    An active and reactive power (P-Q) simultaneous control scheme which is based on a superconducting magnetic energy storage (SMES) unit is designed to damp out the subsynchronous resonant (SSR) oscillations of a turbine-generator unit. In order to suppress unstable torsional mode oscillations, a proportional-integral-derivative (PID) controller is employed to modulate the active and reactive power input/output of the SMES unit according to speed deviation of the generator shaft. The gains of the proposed PID controller are determined by pole assignment approach based on modal control theory. Eigenvalue analysis of the studied system shows that the PID controller is quite effective over a wide range of operating conditions. Dynamic simulations using the nonlinear system model are also performed to demonstrate the damping effect of the proposed control scheme under disturbance conditions.

  13. Small size transformer provides high power regulation with low ripple and maximum control

    NASA Technical Reports Server (NTRS)

    Manoli, R.; Ulrich, B. R.

    1971-01-01

    Single, variable, transformer/choke device does work of several. Technique reduces drawer assembly physical size and design and manufacturing cost. Device provides power, voltage current and impedance regulation while maintaining maximum control of linearity and ensuring extremely low ripple. Nulling is controlled to very fine degree.

  14. A new system architecture improves output power regulation in electrosurgical generators.

    PubMed

    Friedrichs, Daniel A; Erickson, Robert W; Gilbert, James

    2011-01-01

    A new system architecture for electrosurgical generators inherently produces the ideal electrosurgical output characteristic with near-deadbeat control. Compared to existing technology, this converter significantly improves power regulation, leading to improved surgical outcomes by minimizing thermal spread and tissue charring.

  15. Modeling and Verification of Distributed Generation and Voltage Regulation Equipment for Unbalanced Distribution Power Systems; Annual Subcontract Report, June 2007

    SciTech Connect

    Davis, M. W.; Broadwater, R.; Hambrick, J.

    2007-07-01

    This report summarizes the development of models for distributed generation and distribution circuit voltage regulation equipment for unbalanced power systems and their verification through actual field measurements.

  16. Determination of the relative power density distribution in a heterogeneous reactor from the results of measurements of the reactivity effects and the neutron importance function

    SciTech Connect

    Bobrov, A. A.; Glushkov, E. S.; Zimin, A. A.; Kapitonova, A. V.; Kompaniets, G. V.; Nosov, V. I. Petrushenko, R. P.; Smirnov, O. N.

    2012-12-15

    A method for experimental determination of the relative power density distribution in a heterogeneous reactor based on measurements of fuel reactivity effects and importance of neutrons from a californium source is proposed. The method was perfected on two critical assembly configurations at the NARCISS facility of the Kurchatov Institute, which simulated a small-size heterogeneous nuclear reactor. The neutron importance measurements were performed on subcritical and critical assemblies. It is shown that, along with traditionally used activation methods, the developed method can be applied to experimental studies of special features of the power density distribution in critical assemblies and reactors.

  17. Determination of the relative power density distribution in a heterogeneous reactor from the results of measurements of the reactivity effects and the neutron importance function

    NASA Astrophysics Data System (ADS)

    Bobrov, A. A.; Glushkov, E. S.; Zimin, A. A.; Kapitonova, A. V.; Kompaniets, G. V.; Nosov, V. I.; Petrushenko, R. P.; Smirnov, O. N.

    2012-12-01

    A method for experimental determination of the relative power density distribution in a heterogeneous reactor based on measurements of fuel reactivity effects and importance of neutrons from a californium source is proposed. The method was perfected on two critical assembly configurations at the NARCISS facility of the Kurchatov Institute, which simulated a small-size heterogeneous nuclear reactor. The neutron importance measurements were performed on subcritical and critical assemblies. It is shown that, along with traditionally used activation methods, the developed method can be applied to experimental studies of special features of the power density distribution in critical assemblies and reactors.

  18. Proteinase activated receptor-2-mediated dual oxidase-2 up-regulation is involved in enhanced airway reactivity and inflammation in a mouse model of allergic asthma.

    PubMed

    Nadeem, Ahmed; Alharbi, Naif O; Vliagoftis, Harissios; Tyagi, Manoj; Ahmad, Sheikh F; Sayed-Ahmed, Mohamed M

    2015-07-01

    Airway epithelial cells (AECs) express a variety of receptors, which sense danger signals from various aeroallergens/pathogens being inhaled constantly. Proteinase-activated receptor 2 (PAR-2) is one such receptor and is activated by cockroach allergens, which have intrinsic serine proteinase activity. Recently, dual oxidases (DUOX), especially DUOX-2, have been shown to be involved in airway inflammation in response to Toll-like receptor activation. However, the association between PAR-2 and DUOX-2 has not been explored in airways of allergic mice. Therefore, this study investigated the contribution of DUOX-2/reactive oxygen species (ROS) signalling in airway reactivity and inflammation after PAR-2 activation. Mice were sensitized intraperitoneally with intact cockroach allergen extract (CE) in the presence of aluminium hydroxide followed by intranasal challenge with CE. Mice were then assessed for airway reactivity, inflammation, oxidative stress (DUOX-2, ROS, inducible nitric oxide synthase, nitrite, nitrotyrosine and protein carbonyls) and apoptosis (Bax, Bcl-2, caspase-3). Challenge with CE led to up-regulation of DUOX-2 and ROS in AECs with concomitant increases in airway reactivity/inflammation and parameters of oxidative stress, and apoptosis. All of these changes were significantly inhibited by intranasal administration of ENMD-1068, a small molecule antagonist of PAR-2 in allergic mice. Administration of diphenyliodonium to allergic mice also led to improvement of allergic airway responses via inhibition of the DUOX-2/ROS pathway; however, these effects were less pronounced than PAR-2 antagonism. The current study suggests that PAR-2 activation leads to up-regulation of the DUOX-2/ROS pathway in AECs, which is involved in regulation of airway reactivity and inflammation via oxidative stress and apoptosis.

  19. Pleiotrophin-induced endothelial cell migration is regulated by xanthine oxidase-mediated generation of reactive oxygen species.

    PubMed

    Tsirmoula, Sotiria; Lamprou, Margarita; Hatziapostolou, Maria; Kieffer, Nelly; Papadimitriou, Evangelia

    2015-03-01

    Pleiotrophin (PTN) is a heparin-binding growth factor that induces cell migration through binding to its receptor protein tyrosine phosphatase beta/zeta (RPTPβ/ζ) and integrin alpha v beta 3 (ανβ3). In the present work, we studied the effect of PTN on the generation of reactive oxygen species (ROS) in human endothelial cells and the involvement of ROS in PTN-induced cell migration. Exogenous PTN significantly increased ROS levels in a concentration and time-dependent manner in both human endothelial and prostate cancer cells, while knockdown of endogenous PTN expression in prostate cancer cells significantly down-regulated ROS production. Suppression of RPTPβ/ζ through genetic and pharmacological approaches, or inhibition of c-src kinase activity abolished PTN-induced ROS generation. A synthetic peptide that blocks PTN-ανβ3 interaction abolished PTN-induced ROS generation, suggesting that ανβ3 is also involved. The latter was confirmed in CHO cells that do not express β3 or over-express wild-type β3 or mutant β3Y773F/Y785F. PTN increased ROS generation in cells expressing wild-type β3 but not in cells not expressing or expressing mutant β3. Phosphoinositide 3-kinase (PI3K) or Erk1/2 inhibition suppressed PTN-induced ROS production, suggesting that ROS production lays down-stream of PI3K or Erk1/2 activation by PTN. Finally, ROS scavenging and xanthine oxidase inhibition completely abolished both PTN-induced ROS generation and cell migration, while NADPH oxidase inhibition had no effect. Collectively, these data suggest that xanthine oxidase-mediated ROS production is required for PTN-induced cell migration through the cell membrane functional complex of ανβ3 and RPTPβ/ζ and activation of c-src, PI3K and ERK1/2 kinases.

  20. NTRC and chloroplast-generated reactive oxygen species regulate Pseudomonas syringae pv. tomato disease development in tomato and Arabidopsis.

    PubMed

    Ishiga, Yasuhiro; Ishiga, Takako; Wangdi, Tamding; Mysore, Kirankumar S; Uppalapati, Srinivasa Rao

    2012-03-01

    Coronatine (COR)-producing pathovars of Pseudomonas syringae, including pvs. tomato, maculicola, and glycinea, cause important diseases on tomato, crucifers, and soybean, respectively, and produce symptoms with necrotic lesions surrounded by chlorosis. The chlorosis is mainly attributed to COR. However, the significance of COR-induced chlorosis in localized lesion development and the molecular basis of disease-associated cell death is largely unknown. To identify host (chloroplast) genes that play a role in COR-mediated chlorosis, we used a forward genetics approach using Nicotiana benthamiana and virus-induced gene silencing and identified a gene which encodes 2-Cys peroxiredoxin (Prxs) that, when silenced, produced a spreading hypersensitive or necrosis-like phenotype instead of chlorosis after COR application in a COI1-dependent manner. Loss-of-function analysis of Prx and NADPH-dependent thioredoxin reductase C (NTRC), the central players of a chloroplast redox detoxification system, resulted in spreading accelerated P. syringae pv. tomato DC3000 disease-associated cell death with enhanced reactive oxygen species (ROS) accumulation in a COR-dependent manner in tomato and Arabidopsis. Consistent with these results, virulent strain DC3000 suppressed the expression of Prx and NTRC in Arabidopsis and tomato during pathogenesis. However, interestingly, authentic COR suppressed the expression of Prx and NTRC in tomato but not in Arabidopsis, suggesting that COR in conjunction with other effectors may modulate ROS and cell death in different host species. Taken together, these results indicated that NTRC or Prx function as a negative regulator of pathogen-induced cell death in the healthy tissues that surround the lesions, and COR-induced chloroplast-localized ROS play a role in enhancing the disease-associated cell death.

  1. Reactive Oxygen Species Regulate Hematopoietic Stem Cell Self-Renewal, Migration and Development, As Well As Their Bone Marrow Microenvironment

    PubMed Central

    Ludin, Aya; Gur-Cohen, Shiri; Golan, Karin; Kaufmann, Kerstin B.; Itkin, Tomer; Medaglia, Chiara; Lu, Xin-Jiang; Ledergor, Guy; Kollet, Orit

    2014-01-01

    Abstract Significance: Blood forming, hematopoietic stem cells (HSCs) mostly reside in the bone marrow in a quiescent, nonmotile state via adhesion interactions with stromal cells and macrophages. Quiescent, proliferating, and differentiating stem cells have different metabolism, and accordingly different amounts of intracellular reactive oxygen species (ROS). Importantly, ROS is not just a byproduct of metabolism, but also plays a role in stem cell state and function. Recent Advances: ROS levels are dynamic and reversibly dictate enhanced cycling and myeloid bias in ROShigh short-term repopulating stem cells, and ROSlow quiescent long-term repopulating stem cells. Low levels of ROS, regulated by intrinsic factors such as cell respiration or nicotinamide adenine dinucleotide phosphate-oxidase (NADPH oxidase) activity, or extrinsic factors such as stem cell factor or prostaglandin E2 are required for maintaining stem cell self-renewal. High ROS levels, due to stress and inflammation, induce stem cell differentiation and enhanced motility. Critical Issues: Stem cells need to be protected from high ROS levels to avoid stem cell exhaustion, insufficient host immunity, and leukemic transformation that may occur during chronic inflammation. However, continuous low ROS production will lead to lack of stem cell function and opportunistic infections. Ultimately, balanced ROS levels are crucial for maintaining the small stem cell pool and host immunity, both in homeostasis and during stress situations. Future Directions: Deciphering the signaling pathway of ROS in HSC will provide a better understanding of ROS roles in switching HSC from quiescence to activation and vice versa, and will also shed light on the possible roles of ROS in leukemia initiation and development. Antioxid. Redox Signal. 21, 1605–1619. PMID:24762207

  2. Nitric Oxide and Reactive Oxygen Species Coordinately Regulate the Germination of Puccinia striiformis f. sp. tritici Urediniospores

    PubMed Central

    Yin, Shuining; Gao, Zhijuan; Wang, Chenfang; Huang, Lili; Kang, Zhensheng; Zhang, Hongchang

    2016-01-01

    Nitric oxide (NO) and reactive oxygen species (ROS) function as signaling molecules in a number of critical signal transduction pathways in plants, including plant biotic interactions. In addition to the role of plant-derived NO and ROS in plant resistance, which has been well documented, pathogen-produced NO and ROS have recently emerged as important players in fungal development and pathogenesis. However, the effects of pathogenic fungi-derived NO and ROS on signaling pathways during fungal pre-infection development remain unknown. Here, using a combination of pharmacological approaches and confocal microscopy, we investigated the roles of NO and ROS during the germination of Puccinia striiformis Westend f. sp. tritici (Pst) the wheat stripe rust pathogen. Both NO and ROS have a crucial role in uredinial germination. The scavengers of NO and ROS delayed spore germination and decreased the lengths of germ tubes. A similar phenotype was produced after treatment with the promoter. However, the spores germinated and grew normally when the levels of NO and ROS were simultaneously elevated by the application of a promoter of NO and a donor of ROS. Confocal laser microscopy indicated that both NO and ROS preferentially localized at the germ pores and apexes of growing germ tubes when the ROS/NO ratio in the spores was maintained in a specific range. We concluded that both NO and ROS are critical signaling molecules in the pre-infection development of Pst and that the polar growth of the germ tube is coordinately regulated by NO and ROS. PMID:26941716

  3. RhoA and Rac1 GTPases Differentially Regulate Agonist-Receptor Mediated Reactive Oxygen Species Generation in Platelets

    PubMed Central

    Akbar, Huzoor; Duan, Xin; Saleem, Saima; Davis, Ashley K.; Zheng, Yi

    2016-01-01

    Agonist induced generation of reactive oxygen species (ROS) by NADPH oxidases (NOX) enhances platelet aggregation and hence the risk of thrombosis. RhoA and Rac1 GTPases are involved in ROS generation by NOX in a variety of cells, but their roles in platelet ROS production remain unclear. In this study we used platelets from RhoA and Rac1 conditional knockout mice as well as human platelets treated with Rhosin and NSC23767, rationally designed small molecule inhibitors of RhoA and Rac GTPases, respectively, to better define the contributions of RhoA and Rac1 signaling to ROS generation and platelet activation. Treatment of platelets with Rhosin inhibited: (a) U46619 induced activation of RhoA; (b) phosphorylation of p47phox, a critical component of NOX; (c) U46619 or thrombin induced ROS generation; (d) phosphorylation of myosin light chain (MLC); (e) platelet shape change; (f) platelet spreading on immobilized fibrinogen; and (g) release of P-selectin, secretion of ATP and aggregation. Conditional deletion of RhoA or Rac1 gene inhibited thrombin induced ROS generation in platelets. Addition of Y27632, a RhoA inhibitor, NSC23766 or Phox-I, an inhibitor of Rac1-p67phox interaction, to human platelets blocked thrombin induced ROS generation. These data suggest that: (a) RhoA/ROCK/p47phox signaling axis promotes ROS production that, at least in part, contributes to platelet activation in conjunction with or independent of the RhoA/ROCK mediated phosphorylation of MLC; and (b) RhoA and Rac1 differentially regulate ROS generation by inhibiting phosphorylation of p47phox and Rac1-p67phox interaction, respectively. PMID:27681226

  4. Distributed cooperative regulation for multiagent systems and its applications to power systems: a survey.

    PubMed

    Hu, Jianqiang; Li, Yaping; Yong, Taiyou; Cao, Jinde; Yu, Jie; Mao, Wenbo

    2014-01-01

    Cooperative regulation of multiagent systems has become an active research area in the past decade. This paper reviews some recent progress in distributed coordination control for leader-following multiagent systems and its applications in power system and mainly focuses on the cooperative tracking control in terms of consensus tracking control and containment tracking control. Next, methods on how to rank the network nodes are summarized for undirected/directed network, based on which one can determine which follower should be connected to leaders such that partial followers can perceive leaders' information. Furthermore, we present a survey of the most relevant scientific studies investigating the regulation and optimization problems in power systems based on distributed strategies. Finally, some potential applications in the frequency tracking regulation of smart grids are discussed at the end of the paper.

  5. Distributed Cooperative Regulation for Multiagent Systems and Its Applications to Power Systems: A Survey

    PubMed Central

    Li, Yaping; Yong, Taiyou; Yu, Jie; Mao, Wenbo

    2014-01-01

    Cooperative regulation of multiagent systems has become an active research area in the past decade. This paper reviews some recent progress in distributed coordination control for leader-following multiagent systems and its applications in power system and mainly focuses on the cooperative tracking control in terms of consensus tracking control and containment tracking control. Next, methods on how to rank the network nodes are summarized for undirected/directed network, based on which one can determine which follower should be connected to leaders such that partial followers can perceive leaders' information. Furthermore, we present a survey of the most relevant scientific studies investigating the regulation and optimization problems in power systems based on distributed strategies. Finally, some potential applications in the frequency tracking regulation of smart grids are discussed at the end of the paper. PMID:25243199

  6. Autophagy-related gene 7 (ATG7) and reactive oxygen species/extracellular signal-regulated kinase regulate tetrandrine-induced autophagy in human hepatocellular carcinoma.

    PubMed

    Gong, Ke; Chen, Chao; Zhan, Yao; Chen, Yan; Huang, Zebo; Li, Wenhua

    2012-10-12

    Tetrandrine, a bisbenzylisoquinoline alkaloid isolated from the broadly used Chinese medicinal herb Stephaniae tetrandrae, exhibits potent antitumor effects and has the potential to be used as a cancer chemotherapeutic agent. We previously reported that high concentrations of tetrandrine induce apoptosis in liver cancer cells. Here, we found that in human hepatocellular carcinoma (HCC) cells, a low dose of tetrandrine (5 μm) induced the expression of LC3-II, resulted in the formation of acidic autophagolysosome vacuoles (AVOs), and caused a punctate fluorescence pattern with the GFP-LC3 protein, which all are markers for cellular autophagy. Tetrandrine induced the production of intracellular reactive oxygen species (ROS), and treatment with ROS scavengers significantly abrogated the tetrandrine-induced autophagy. These results suggest that the generation of ROS plays an important role in promoting tetrandrine-induced autophagy. Tetrandrine-induced mitochondrial dysfunction resulted in ROS accumulation and autophagy. ROS generation activated the ERK MAP kinase, and the ERK signaling pathway at least partially contributed to tetrandrine-induced autophagy in HCC cells. Moreover, we found that tetrandrine transcriptionally regulated the expression of autophagy related gene 7 (ATG7), which promoted tetrandrine-induced autophagy. In addition to in vitro studies, similar results were also observed in vivo, where tetrandrine caused the accumulation of ROS and induced cell autophagy in a tumor xenograft model. Interestingly, tetrandrine treatment also induced autophagy in a ROS-dependent manner in C. elegans muscle cells. Therefore, these findings suggest that tetrandrine is a potent autophagy agonist and may be a promising clinical chemotherapeutic agent.

  7. Active power control of solar PV generation for large interconnection frequency regulation and oscillation damping

    DOE PAGES

    Liu, Yong; Zhu, Lin; Zhan, Lingwei; ...

    2015-06-23

    Because of zero greenhouse gas emission and decreased manufacture cost, solar photovoltaic (PV) generation is expected to account for a significant portion of future power grid generation portfolio. Because it is indirectly connected to the power grid via power electronic devices, solar PV generation system is fully decoupled from the power grid, which will influence the interconnected power grid dynamic characteristics as a result. In this study, the impact of solar PV penetration on large interconnected power system frequency response and inter-area oscillation is evaluated, taking the United States Eastern Interconnection (EI) as an example. Furthermore, based on the constructedmore » solar PV electrical control model with additional active power control loops, the potential contributions of solar PV generation to power system frequency regulation and oscillation damping are examined. The advantages of solar PV frequency support over that of wind generator are also discussed. Finally, simulation results demonstrate that solar PV generations can effectively work as ‘actuators’ in alleviating the negative impacts they bring about.« less

  8. Active power control of solar PV generation for large interconnection frequency regulation and oscillation damping

    SciTech Connect

    Liu, Yong; Zhu, Lin; Zhan, Lingwei; Gracia, Jose R.; King, Thomas Jr.; Liu, Yilu

    2015-06-23

    Because of zero greenhouse gas emission and decreased manufacture cost, solar photovoltaic (PV) generation is expected to account for a significant portion of future power grid generation portfolio. Because it is indirectly connected to the power grid via power electronic devices, solar PV generation system is fully decoupled from the power grid, which will influence the interconnected power grid dynamic characteristics as a result. In this study, the impact of solar PV penetration on large interconnected power system frequency response and inter-area oscillation is evaluated, taking the United States Eastern Interconnection (EI) as an example. Furthermore, based on the constructed solar PV electrical control model with additional active power control loops, the potential contributions of solar PV generation to power system frequency regulation and oscillation damping are examined. The advantages of solar PV frequency support over that of wind generator are also discussed. Finally, simulation results demonstrate that solar PV generations can effectively work as ‘actuators’ in alleviating the negative impacts they bring about.

  9. Lightweight Battery Charge Regulator Used to Track Solar Array Peak Power

    NASA Technical Reports Server (NTRS)

    Soeder, James F.; Button, Robert M.

    1999-01-01

    A battery charge regulator based on the series-connected boost regulator (SCBR) technology has been developed for high-voltage spacecraft applications. The SCBR regulates the solar array power during insolation to prevent battery overcharge or undercharge conditions. It can also be used to provide regulated battery output voltage to spacecraft loads if necessary. This technology uses industry-standard dc-dc converters and a unique interconnection to provide size, weight, efficiency, fault tolerance, and modularity benefits over existing systems. The high-voltage SCBR shown in the photograph has demonstrated power densities of over 1000 watts per kilogram (W/kg). Using four 150-W dc-dc converter modules, it can process 2500 W of power at 120 Vdc with a minimum input voltage of 90 Vdc. Efficiency of the SCBR was 94 to 98 percent over the entire operational range. Internally, the unit is made of two separate SCBR s, each with its own analog control circuitry, to demonstrate the modularity of the technology. The analog controllers regulate the output current and incorporate the output voltage limit with active current sharing between the two units. They also include voltage and current telemetry, on/off control, and baseplate temperature sensors. For peak power tracking, the SCBR was connected to a LabView-based data acquisition system for telemetry and control. A digital control algorithm for tracking the peak power point of a solar array was developed using the principle of matching the source impedance with the load impedance for maximum energy transfer. The algorithm was successfully demonstrated in a simulated spacecraft electrical system at the Boeing PhantomWorks High Voltage Test Facility in Seattle, Washington. The system consists of a 42-string, high-voltage solar array simulator, a 77-cell, 80-ampere-hour (A-hr) nickel-hydrogen battery, and a constant power-load module. The SCBR and the LabView control algorithm successfully tracked the solar array peak

  10. Calculation and comparison of xenon and samarium reactivities of the HEU, LEU core in the low power research reactor.

    PubMed

    Dawahra, S; Khattab, K; Saba, G

    2015-07-01

    Comparative studies for the conversion of the fuel from HEU to LEU in the Miniature Neutron Source Reactor (MNSR) have been performed using the MCNP4C and GETERA codes. The precise calculations of (135)Xe and (149)Sm concentrations and reactivities were carried out and compared during the MNSR operation time and after shutdown for the existing HEU fuel (UAl4-Al, 90% enriched) and the potential LEU fuels (U3Si2-Al, U3Si-Al, U9Mo-Al, 19.75% enriched and UO2, 12.6% enriched) in this paper using the MCNP4C and GETERA codes. It was found that the (135)Xe and (149)Sm reactivities did not reach their equilibrium reactivities during the daily operating time of the reactor. The (149)Sm reactivities could be neglected compared to (135)Xe reactivities during the reactor operating time and after shutdown. The calculations for the UAl4-Al produced the highest (135)Xe reactivity in all the studied fuel group during the reactor operation (0.39 mk) and after the reactor shutdown (0.735 mk), It followed by U3Si-Al (0.34 mk, 0.653 mk), U3Si2-Al (0.33 mk, 0.634 mk), U9Mo-Al (0.3 mk, 0.568 mk) and UO2 (0.24 mk, 0.448 mk) fuels, respectively. Finally, the results showed that the UO2 was the best candidate for fuel conversion to LEU in the MNSR since it gave the lowest (135)Xe reactivity during the reactor operation and after shutdown.

  11. Harnessing Evolutionary Toxins for Signaling: Reactive Oxygen Species, Nitric Oxide and Hydrogen Sulfide in Plant Cell Regulation

    PubMed Central

    Hancock, John T.

    2017-01-01

    During the early periods of evolution, as well as in niche environments today, organisms have had to learn to tolerate the presence of many reactive compounds, such as reactive oxygen species, nitric oxide, and hydrogen sulfide. It is now known that such compounds are instrumental in the signaling processes in plant cells. There are enzymes which can make them, while downstream of their signaling pathways are coming to light. These include the production of cGMP, the activation of MAP kinases and transcription factors, and the modification of thiol groups on many proteins. However, organisms have also had to tolerate other reactive compounds such as ammonia, methane, and hydrogen gas, and these too are being found to have profound effects on signaling in cells. Before a holistic view of how such signaling works, the full effects and interactions of all such reactive compounds needs to be embraced. A full understanding will be beneficial to both agriculture and future therapeutic strategies. PMID:28239389

  12. 47 CFR 74.789 - Broadcast regulations applicable to digital low power television and television translator stations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 4 2012-10-01 2012-10-01 false Broadcast regulations applicable to digital low....789 Broadcast regulations applicable to digital low power television and television translator stations. The following sections are applicable to digital low power television and television...

  13. 47 CFR 74.789 - Broadcast regulations applicable to digital low power television and television translator stations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 4 2013-10-01 2013-10-01 false Broadcast regulations applicable to digital low....789 Broadcast regulations applicable to digital low power television and television translator stations. The following sections are applicable to digital low power television and television...

  14. 47 CFR 74.789 - Broadcast regulations applicable to digital low power television and television translator stations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Broadcast regulations applicable to digital low....789 Broadcast regulations applicable to digital low power television and television translator stations. The following sections are applicable to digital low power television and television...

  15. 47 CFR 74.789 - Broadcast regulations applicable to digital low power television and television translator stations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 4 2011-10-01 2011-10-01 false Broadcast regulations applicable to digital low....789 Broadcast regulations applicable to digital low power television and television translator stations. The following sections are applicable to digital low power television and television...

  16. 47 CFR 74.789 - Broadcast regulations applicable to digital low power television and television translator stations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 4 2014-10-01 2014-10-01 false Broadcast regulations applicable to digital low....789 Broadcast regulations applicable to digital low power television and television translator stations. The following sections are applicable to digital low power television and television...

  17. Soft-stall control versus furling control for small wind turbine power regulation

    SciTech Connect

    Muljadi, E; Forsyth, T; Butterfield, C P

    1998-07-01

    Many small wind turbines are designed to furl (turn) in high winds to regulate power and provide overspeed protection. Furling control results in poor energy capture at high wind speeds. This paper proposes an alternative control strategy for small wind turbines -- the soft-stall control method. The furling and soft-stall control strategies are compared using steady state analysis and dynamic simulation analysis. The soft-stall method is found to offer several advantages: increased energy production at high wind speeds, energy production which tracks the maximum power coefficient at low to medium wind speeds, reducing furling noise, and reduced thrust.

  18. Soft-Stall Control versus Furling Control for Small Wind Turbine Power Regulation

    SciTech Connect

    Muljadi, E.; Forsyth, T.; Butterfield, C. P.

    1998-07-01

    Many small wind turbines are designed to furl (turn) in high winds to regulate power and provide overspeed protection. Furling control results in poor energy capture at high wind speeds. This paper proposes an alternative control strategy for small wind turbines -- the soft-stall method. The furling and soft-stall control strategies are compared using steady state analysis and dynamic simulation analysis. The soft-stall method is found to offer several advantages: increased energy production at high wind speeds, energy production which tracks the maximum power coefficient at low to medium wind speeds, reduced furling noise, and reduced thrust.

  19. High voltage solar cell power generating system for regulated solar array development

    NASA Technical Reports Server (NTRS)

    Levy, E., Jr.; Hoffman, A. C.

    1973-01-01

    A laboratory solar power system regulated by on-panel switches has been delivered for operating high power (3 kw), high voltage (15,000 volt) loads (communication tubes, ion thrusters). The modular system consists of 26 solar arrays, each with an integral light source and cooling system. A typical array contains 2560 series-connected cells. Each light source consists of twenty 500 watt tungsten iodide lamps providing plus or minus 5 per cent uniformity at one solar constant. An array temperature of less than 40 C is achieved using an infrared filter, a water cooled plate, a vacuum hold-down system, and air flushing.

  20. Efficiency and Regulation of Commercial Low Power DC/DC Converter Modules at Low Temperatures

    NASA Technical Reports Server (NTRS)

    Elbuluk, Malik E.; Gerber, Scott; Hammoud, Ahmad; Patterson, Richard L.

    2000-01-01

    DC/DC converters that are capable of operating at cryogenic temperatures are anticipated to play an important role in the power systems of future NASA deep space missions. Design of these converters to survive cryogenic temperatures will improve the power system performance, and reduce development and launch costs. At the NASA Glenn Research Center Low Temperature Electronics Laboratory, several commercial off-the-shelf dc/dc converter modules were evaluated for their low temperature performance. Various parameters were investigated as a function of temperature, in the range of 20 C to -190 C. Data pertaining to the efficiency and voltage regulation of the tested converters is presented and discussed.

  1. Economic and safety analysis of unconventional peak regulation on power unit of peak shifting start-stop

    NASA Astrophysics Data System (ADS)

    Cao, X.; Zhao, J. F.; Duan, X. Q.; Jin, Y. A.

    2017-01-01

    Tthe capacity difference of peak regulation between the power gird and the actual demand has become a serious problem considering the growth in the difference between electricity supply and demand. Therefore, peak regulation of power grid needs to be deeply studied. Unconventional peak regulation on unit of peak shifting start-stop is a way that can broaden the range of power regulation, as well as benefit safe operation of the power grid. However, it requires frequent and fast unit start-stop, complex operation, and more staff labor. By carrying out unconventional thermal power unit load test, the start-stop mode of peak auxiliary equipment is studied in this paper, indicating that it has a positive effect on safety and economic of load-peaking operation. The best working conditions of the peak units is found by analysing consumption cost, safety specifications, and life lost of the start-stop peak regulation mode.

  2. Applying and adapting the Swedish regulatory system for decommissioning to nuclear power reactors - The regulator's perspective.

    PubMed

    Amft, Martin; Leisvik, Mathias; Carroll, Simon

    2017-03-16

    Half of the original 13 Swedish nuclear power reactors will be shut down by 2020. The decommissioning of these reactors is a challenge for all parties involved, including the licensees, the waste management system, the financing system, and the Swedish Radiation Safety Authority (SSM). This paper presents an overview of the Swedish regulations for decommissioning of nuclear facilities. It describes some of the experiences that SSM has gained from the application of these regulations. The focus of the present paper is on administrative aspects of decommissioning, such as SSM's guidelines, the definition of fundamental concepts in the regulatory framework, and a proposed revision of the licensing process according to the Environmental Act. These improvements will help to streamline the administration of the commercial nuclear power plant decommissioning projects that are anticipated to commence in Sweden in the near future.

  3. Power spectra and cooperativity of a calcium-regulated cation channel.

    PubMed

    McGeoch, M W; McGeoch, J E

    1994-01-01

    In this article we show that a channel complex of cooperatively interacting subunits can produce a power law spectrum with the slope of the spectrum depending on the strength of the cooperative interaction. The effects of cooperativity are explored via a computational model of a calcium-regulated cation channel for which new data is presented. The results, which concern "flickering" conductances, are correlated with prior work on critical fluctuations in the Ising model of ferromagnetism.

  4. 25 CFR 518.12 - Which investigative or enforcement powers of the Commission are inapplicable to self-regulating...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Commission are inapplicable to self-regulating tribes? 518.12 Section 518.12 Indians NATIONAL INDIAN GAMING COMMISSION, DEPARTMENT OF THE INTERIOR GENERAL PROVISIONS SELF-REGULATION OF CLASS II GAMING § 518.12 Which... time in which a tribe has a certificate of self-regulation, the powers of the Commission, as set...

  5. Trends in the use of digital technology for control and regulation of power supplies.

    SciTech Connect

    Carwardine, J.; Lenkszus, F.

    1999-10-22

    Since the availability of computers, accelerator power supplies have relied on digital technology in some way, from such simple tasks as turning the supplies on and off to the supplying of computer-controlled references. However, advances in digital technology, both in performance and cost, allow considerably more than simple control and monitoring. This, coupled with increasing demand for higher performance and monitoring capabilities, has made it appealing to integrate such technology into power supply designs. This paper will review current trends in the use of such advanced technology as embedded DSP controllers, and the application of real-time algorithms to the regulation and control of power supplies for accelerators and other large-scale physics applications.

  6. Peripheral self-reactivity regulates antigen-specific CD8 T-cell responses and cell division under physiological conditions

    PubMed Central

    Swee, Lee Kim; Tan, Zhen Wei; Sanecka, Anna; Yoshida, Nagisa; Patel, Harshil; Grotenbreg, Gijsbert; Ploegh, Hidde L.

    2016-01-01

    T-cell identity is established by the expression of a clonotypic T-cell receptor (TCR), generated by somatic rearrangement of TCRα and β genes. The properties of the TCR determine both the degree of self-reactivity and the repertoire of antigens that can be recognized. For CD8 T cells, the relationship between TCR identity—hence reactivity to self—and effector function(s) remains to be fully understood and has rarely been explored outside of the H-2b haplotype. We measured the affinity of three structurally distinct CD8 T-cell-derived TCRs that recognize the identical H-2 Ld-restricted epitope, derived from the Rop7 protein of Toxoplasma gondii. We used CD8 T cells obtained from mice generated by somatic cell nuclear transfer as the closest approximation of primary T cells with physiological TCR rearrangements and TCR expression levels. First, we demonstrate the common occurrence of secondary rearrangements in endogenously rearranged loci. Furthermore, we characterized and compared the response of Rop7-specific CD8 T-cell clones upon Toxoplasma gondii infection as well as effector function and TCR signalling upon antigenic stimulation in vitro. Antigen-independent TCR cross-linking in vitro uncovered profound intrinsic differences in the effector functions between T-cell clones. Finally, by assessing the degree of self-reactivity and comparing the transcriptomes of naive Rop7 CD8 T cells, we show that lower self-reactivity correlates with lower effector capacity, whereas higher self-reactivity is associated with enhanced effector function as well as cell cycle entry under physiological conditions. Altogether, our data show that potential effector functions and basal proliferation of CD8 T cells are set by self-reactivity thresholds. PMID:27881740

  7. Technology diffusion and environmental regulation: Evidence from electric power plants under the Clean Air Act

    NASA Astrophysics Data System (ADS)

    Frey, Elaine F.

    Even though environmental policy can greatly affect the path of technology diffusion, the economics literature contains limited empirical evidence of this relationship. My research will contribute to the available evidence by providing insight into the technology adoption decisions of electric generating firms. Since policies are often evaluated based on the incentives they provide to promote adoption of new technologies, it is important that policy makers understand the relationship between technological diffusion and regulation structure to make informed decisions. Lessons learned from this study can be used to guide future policies such as those directed to mitigate climate change. I first explore the diffusion of scrubbers, a sulfur dioxide (SO 2) abatement technology, in response to federal market-based regulations and state command-and-control regulations. I develop a simple theoretical model to describe the adoption decisions of scrubbers and use a survival model to empirically test the theoretical model. I find that power plants with strict command-and-control regulations have a high probability of installing a scrubber. These findings suggest that although market-based regulations have encouraged diffusion, many scrubbers have been installed because of state regulatory pressure. Although tradable permit systems are thought to give firms more flexibility in choosing abatement technologies, I show that interactions between a permit system and pre-existing command-and-control regulations can limit that flexibility. In a separate analysis, I explore the diffusion of combined cycle (CC) generating units, which are natural gas-fired generating units that are cleaner and more efficient than alternative generating units. I model the decision to consider adoption of a CC generating unit and the extent to which the technology is adopted in response to environmental regulations imposed on new sources of pollutants. To accomplish this, I use a zero-inflated Poisson

  8. Ferric nitrilotriacetate (Fe-NTA)-induced reactive oxidative species protects human hepatic stellate cells from apoptosis by regulating Bcl-2 family proteins and mitochondrial membrane potential

    PubMed Central

    Liu, Mei; Li, Shu-Jie; Xin, Yong-Ning; Ji, Shu-Sheng; Xie, Rui-Jin; Xuan, Shi-Ying

    2015-01-01

    Reactive oxidative species (ROS)-induced apoptosis of human hepatic stellate (HSC) is one of the treatments for liver fibrosis. However, how ROS (reactive oxygen species) affect HSC apoptosis and liver fibrosis is still unknown. In our study, ROS in human HSC cell line LX-2 was induced by ferric nitrilotriacetate (Fe-NTA) and assessed by superoxide dismutase (SOD) activity and methane dicarboxylic aldehyde (MDA) level. We found that in LX2 cells Fe-NTA induced notable ROS, which played a protective role in HSCs cells apoptosis by inhibiting Caspase-3 activation. Fe-NTA-induced ROS increased mRNA and protein level of anti-apoptosis Bcl-2 and decreased mRNA protein level of pro-apoptosis gene Bax, As a result, maintaining mitochondrial membrane potential of HSCs. Fe-NTA-induced ROS play a protective role in human HSCs by regulating Bcl-2 family proteins and mitochondrial membrane potential. PMID:26770403

  9. A Method for Compensating Customer Voltage Drops due to Nighttime Simultaneous Charging of EVs Utilizing Reactive Power Injection from Battery Chargers

    NASA Astrophysics Data System (ADS)

    Noda, Taku; Kabasawa, Yuichiro; Fukushima, Kentaro; Nemoto, Koshichi; Uemura, Satoshi

    When we consider the global warming, the reduction of CO2 emission is one of the most important problems which require urgent solutions. One option is to integrate low-CO2-emission generators to the grid as much as possible. Another option is to replace inefficient vehicles based on internal-combustion engines with electric ones (EVs). Due to the latter, we can easily estimate that most consumers will charge EVs' batteries at nighttime. Thus, excessive voltage drops due to the nighttime simultaneous charging are supposed to be a possible future problem. This paper proposes a method for compensating the voltage drops by injecting reactive power from EV battery chargers.

  10. Coordination and decision making of regulation, operation, and market activities in power systems

    NASA Astrophysics Data System (ADS)

    Nakashima, Tomoaki

    Electric power has been traditionally supplied to customers at regulated rates by vertically integrated utilities (VIUs), which own generation, transmission, and distribution systems. However, the regulatory authorities of VIUs are promoting competition in their businesses to lower the price of electric energy. Consequently, in new deregulated circumstances, many suppliers and marketers compete in the generation market, and conflict of interest may often occur over transmission. Therefore, a neutral entity, called an independent system operator (ISO), which operates the power system independently, has been established to give market participants nondiscriminatory access to transmission sectors with a natural monopoly, and to facilitate competition in generation sectors. Several types of ISOs are established at present, with their respective regions and authorities. The ISO receives many requests from market participants to transfer power, and must evaluate the feasibility of their requests under the system's condition. In the near future, regulatory authorities may impose various objectives on the ISOs. Then, based on the regulators' policies, the ISO must determine the optimal schedules from feasible solutions, or change the market participants' requests. In a newly developed power market, market participants will conduct their transactions in order to maximize their profit. The most crucial information in conducting power transactions is price and demand. A direct transaction between suppliers and consumers may become attractive because of its stability of price, while in a power exchange market, gaming and speculation of participants may push up electricity prices considerably. To assist the consumers in making effective decisions, suitable methods for forecasting volatile market price are necessary. This research has been approached from three viewpoints: Firstly, from the system operator's point of view, desirable system operation and power market structure

  11. Automatic system for regulating the frequency and power of the 500 MW coal-dust power generating units at the Reftinskaya GRES

    SciTech Connect

    Bilenko, V. A.; Gal'perina, A. I.; Mikushevich, E. E.; Nikol'skii, D. Yu.; Zhugrin, A. G.; Bebenin, P. A.; Syrchin, M. V.

    2009-03-15

    The monitoring and control systems at the 500 MW coal-dust power generating units No. 7, 8, and 9 at the Reftinskaya GRES have been modernized using information-regulator systems. Layouts for instrumental construction of these systems and expanded algorithmic schemes for the automatic frequency and power control system and for the boiler supply and fuelling are discussed. Results from tests and normal operation of the automatic frequency and power control system are presented.

  12. Eicosanoids up-regulate production of reactive oxygen species by NADPH-dependent oxidase in Spodoptera exigua phagocytic hemocytes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Eicosanoids mediate cellular immune responses in insects, including phagocytosis of invading microbes. Phagocytosis entails two major steps, the internalization of microbes and the subsequent killing of them via formation of reactive oxygen species (ROS). Here, we posed the hypothesis that eicosanoi...

  13. Committing to coal and gas: Long-term contracts, regulation, and fuel switching in power generation

    NASA Astrophysics Data System (ADS)

    Rice, Michael

    Fuel switching in the electricity sector has important economic and environmental consequences. In the United States, the increased supply of gas during the last decade has led to substantial switching in the short term. Fuel switching is constrained, however, by the existing infrastructure. The power generation infrastructure, in turn, represents commitments to specific sources of energy over the long term. This dissertation explores fuel contracts as the link between short-term price response and long-term plant investments. Contracting choices enable power plant investments that are relationship-specific, often regulated, and face uncertainty. Many power plants are subject to both hold-up in investment and cost-of-service regulation. I find that capital bias is robust when considering either irreversibility or hold-up due to the uncertain arrival of an outside option. For sunk capital, the rental rate is inappropriate for determining capital bias. Instead, capital bias depends on the regulated rate of return, discount rate, and depreciation schedule. If policies such as emissions regulations increase fuel-switching flexibility, this can lead to capital bias. Cost-of-service regulation can shorten the duration of a long-term contract. From the firm's perspective, the existing literature provides limited guidance when bargaining and writing contracts for fuel procurement. I develop a stochastic programming framework to optimize long-term contracting decisions under both endogenous and exogenous sources of hold-up risk. These typically include policy changes, price shocks, availability of fuel, and volatility in derived demand. For price risks, the optimal contract duration is the moment when the expected benefits of the contract are just outweighed by the expected opportunity costs of remaining in the contract. I prove that imposing early renegotiation costs decreases contract duration. Finally, I provide an empirical approach to show how coal contracts can limit

  14. Sampling strategies and materials for investigating large reactive particle complaints from Valley Village homeowners near a coal-fired power plant

    SciTech Connect

    Chang, A.; Davis, H.; Frazar, B.; Haines, B.

    1997-12-31

    This paper will present Phase 3`s sampling strategies, techniques, methods and substrates for assisting the District to resolve the complaints involving yellowish-brown staining and spotting of homes, cars, etc. These spots could not be easily washed off and some were permanent. The sampling strategies for the three phases were based on Phase 1 -- the identification of the reactive particles conducted in October, 1989 by APCD and IITRI, Phase 2 -- a study of the size distribution and concentration as a function of distance and direction of reactive particle deposition conducted by Radian and LG and E, and Phase 3 -- the determination of the frequency of soiling events over a full year`s duration conducted in 1995 by APCD and IITRI. The sampling methods included two primary substrates -- ACE sheets and painted steel, and four secondary substrates -- mailbox, aluminum siding, painted wood panels and roof tiles. The secondary substrates were the main objects from the Valley Village complaints. The sampling technique included five Valley Village (VV) soiling/staining assessment sites and one southwest of the power plant as background/upwind site. The five VV sites northeast of the power plant covered 50 degrees span sector and 3/4 miles distance from the stacks. Hourly meteorological data for wind speeds and wind directions were collected. Based on this sampling technique, there were fifteen staining episodes detected. Nine of them were in summer, 1995.

  15. αβ T cell receptor germline CDR regions moderate contact with MHC ligands and regulate peptide cross-reactivity

    PubMed Central

    Attaf, Meriem; Holland, Stephan J.; Bartok, Istvan; Dyson, Julian

    2016-01-01

    αβ T cells respond to peptide epitopes presented by major histocompatibility complex (MHC) molecules. The role of T cell receptor (TCR) germline complementarity determining regions (CDR1 and 2) in MHC restriction is not well understood. Here, we examine T cell development, MHC restriction and antigen recognition where germline CDR loop structure has been modified by multiple glycine/alanine substitutions. Surprisingly, loss of germline structure increases TCR engagement with MHC ligands leading to excessive loss of immature thymocytes. MHC restriction is, however, strictly maintained. The peripheral T cell repertoire is affected similarly, exhibiting elevated cross-reactivity to foreign peptides. Our findings are consistent with germline TCR structure optimising T cell cross-reactivity and immunity by moderating engagement with MHC ligands. This strategy may operate alongside co-receptor imposed MHC restriction, freeing germline TCR structure to adopt this novel role in the TCR-MHC interface. PMID:27775030

  16. αβ T cell receptor germline CDR regions moderate contact with MHC ligands and regulate peptide cross-reactivity.

    PubMed

    Attaf, Meriem; Holland, Stephan J; Bartok, Istvan; Dyson, Julian

    2016-10-24

    αβ T cells respond to peptide epitopes presented by major histocompatibility complex (MHC) molecules. The role of T cell receptor (TCR) germline complementarity determining regions (CDR1 and 2) in MHC restriction is not well understood. Here, we examine T cell development, MHC restriction and antigen recognition where germline CDR loop structure has been modified by multiple glycine/alanine substitutions. Surprisingly, loss of germline structure increases TCR engagement with MHC ligands leading to excessive loss of immature thymocytes. MHC restriction is, however, strictly maintained. The peripheral T cell repertoire is affected similarly, exhibiting elevated cross-reactivity to foreign peptides. Our findings are consistent with germline TCR structure optimising T cell cross-reactivity and immunity by moderating engagement with MHC ligands. This strategy may operate alongside co-receptor imposed MHC restriction, freeing germline TCR structure to adopt this novel role in the TCR-MHC interface.

  17. A powerful combination: the use of positional scanning libraries and biometrical analysis to identify cross-reactive T cell epitopes.

    PubMed

    Nino-Vasquez, J Javier; Allicotti, Gina; Borras, Eva; Wilson, Darcy B; Valmori, Danila; Simon, Richard; Martin, Roland; Pinilla, Clemencia

    2004-02-01

    Studies on the elucidation of the specificity of the T cell receptor (TCR) at the antigen and peptide level have contributed to the current understanding of T cell cross-reactivity. Historically, most studies of T cell specificity and degeneracy have relied on the determination of the effects on T cell recognition of amino acid changes at individual positions or MHC binding residues, and thus they have been limited to a small set of possible ligands. Synthetic combinatorial libraries (SCLs), and in particular positional scanning synthetic combinatorial libraries (PS-SCLs) represent collections of millions to trillions of peptides which allow the unbiased elucidation of T cell ligands that stimulate clones of both known and unknown specificity. PS-SCLs have been used successfully to study T cell recognition and to identify and optimize T cell clone (TCC) epitopes in infectious diseases, autoimmune disorders and tumor antigens. PS-SCL-based biometrical analysis represents a further refinement in the analysis of the data derived from the screening of a library with a TCC. It combines this data with information derived from protein sequence databases to identify natural peptide ligands. PS-SCL-based biometrical analysis provides a method for the determination of new microbial antigen and autoantigen sequences based solely on functional data rather than sequence homology or motifs, making the method ideally suited for the prediction and identification of both native and cross-reactive epitopes by virtue of its ability to integrate the examination of trillions of peptides in a systematic manner with all of the protein sequences in a given database. We review here the application of PS-SCLs and biometrical analysis to identify cross-reactive T cell epitopes, as well as the current efforts to refine this strategy.

  18. An analysis of thermionic space nuclear reactor power system: I. Effect of disassembling radial reflector, following a reactivity initiated accident

    SciTech Connect

    El-Genk, M.S.; Paramonov, D. )

    1993-01-10

    An analysis is performed to determine the effect of disassembling the radial reflector of the TOPAZ-II reactor, following a hypothetical severe Reactivity Initiated Accident (RIA). Such an RIA is assumed to occur during the system start-up in orbit due to a malfunction of the drive mechanism of the control drums, causing the drums to rotate the full 180[degree] outward at their maximum speed of 1.4[degree]/s. Results indicate that disassembling only three of twelve radial reflector panels would successfully shutdown the reactor, with little overheating of the fuel and the moderator.

  19. Virtual welding equipment for simulation of GMAW processes with integration of power source regulation

    NASA Astrophysics Data System (ADS)

    Reisgen, Uwe; Schleser, Markus; Mokrov, Oleg; Zabirov, Alexander

    2011-06-01

    A two dimensional transient numerical analysis and computational module for simulation of electrical and thermal characteristics during electrode melting and metal transfer involved in Gas-Metal-Arc-Welding (GMAW) processes is presented. Solution of non-linear transient heat transfer equation is carried out using a control volume finite difference technique. The computational module also includes controlling and regulation algorithms of industrial welding power sources. The simulation results are the current and voltage waveforms, mean voltage drops at different parts of circuit, total electric power, cathode, anode and arc powers and arc length. We describe application of the model for normal process (constant voltage) and for pulsed processes with U/I and I/I-modulation modes. The comparisons with experimental waveforms of current and voltage show that the model predicts current, voltage and electric power with a high accuracy. The model is used in simulation package SimWeld for calculation of heat flux into the work-piece and the weld seam formation. From the calculated heat flux and weld pool sizes, an equivalent volumetric heat source according to Goldak model, can be generated. The method was implemented and investigated with the simulation software SimWeld developed by the ISF at RWTH Aachen University.

  20. Halbach array generator/motor having mechanically regulated output voltage and mechanical power output

    SciTech Connect

    Post, Richard F.

    2005-06-14

    A motor/generator has its stationary portion, i.e., the stator, positioned concentrically within its rotatable element, i.e., the rotor, along the axis of rotation of the rotor. The rotor includes a Halbach array of magnets. The voltage and power outputs are regulated by varying the radial gap in between the stator windings and the rotating Halbach array. The gap is varied by extensible and retractable supports attached to the stator windings that can move the windings in a radial direction.

  1. Microcomputer technology applications: Charger and regulator software for a breadboard programmable power processor

    NASA Technical Reports Server (NTRS)

    Green, D. M.

    1978-01-01

    Software programs are described, one which implements a voltage regulation function, and one which implements a charger function with peak-power tracking of its input. The software, written in modular fashion, is intended as a vehicle for further experimentation with the P-3 system. A control teleprinter allows an operator to make parameter modifications to the control algorithm during experiments. The programs require 3K ROM and 2K ram each. User manuals for each system are included as well as a third program for simple I/O control.

  2. Halbach array generator/motor having an automatically regulated output voltage and mechanical power output

    DOEpatents

    Post, Richard F.

    2005-02-22

    A motor/generator having its stationary portion, i.e., the stator, positioned concentrically within its rotatable element, i.e., the rotor, along its axis of rotation. The rotor includes a Halbach array. The stator windings are switched or commutated to provide a DC motor/generator much the same as in a conventional DC motor/generator. The voltage and power are automatically regulated by using centrifugal force to change the diameter of the rotor, and thereby vary the radial gap in between the stator and the rotating Halbach array, as a function of the angular velocity of the rotor.

  3. Critical Roles of Reactive Oxygen Species in Age-Related Impairment in Ischemia-Induced Neovascularization by Regulating Stem and Progenitor Cell Function

    PubMed Central

    Lam, Yuen Ting

    2016-01-01

    Reactive oxygen species (ROS) regulate bone marrow microenvironment for stem and progenitor cells functions including self-renewal, differentiation, and cell senescence. In response to ischemia, ROS also play a critical role in mediating the mobilization of endothelial progenitor cells (EPCs) from the bone marrow to the sites of ischemic injury, which contributes to postnatal neovascularization. Aging is an unavoidable biological deteriorative process with a progressive decline in physiological functions. It is associated with increased oxidative stress and impaired ischemia-induced neovascularization. This review discusses the roles of ROS in regulating stem and progenitor cell function, highlighting the impact of unbalanced ROS levels on EPC dysfunction and the association with age-related impairment in ischemia-induced neovascularization. Furthermore, it discusses strategies that modulate the oxidative levels of stem and progenitor cells to enhance the therapeutic potential for elderly patients with cardiovascular disease. PMID:26697140

  4. Sexual Preferences in Nutrient Utilization Regulate Oxygen Consumption and Reactive Oxygen Species Generation in Schistosoma mansoni: Potential Implications for Parasite Redox Biology

    PubMed Central

    Oliveira, Matheus P.; Correa Soares, Juliana B. R.; Oliveira, Marcus F.

    2016-01-01

    Schistosoma mansoni, one of the causative agents of human schistosomiasis, has a unique antioxidant network that is key to parasite survival and a valuable chemotherapeutic target. The ability to detoxify and tolerate reactive oxygen species increases along S. mansoni development in the vertebrate host, suggesting that adult parasites are more exposed to redox challenges than young stages. Indeed, adult parasites are exposed to multiple redox insults generated from blood digestion, activated immune cells, and, potentially, from their own parasitic aerobic metabolism. However, it remains unknown how reactive oxygen species are produced by S. mansoni metabolism, as well as their biological effects on adult worms. Here, we assessed the contribution of nutrients and parasite gender to oxygen utilization pathways, and reactive oxygen species generation in whole unpaired adult S. mansoni worms. We also determined the susceptibilities of both parasite sexes to a pro-oxidant challenge. We observed that glutamine and serum importantly contribute to both respiratory and non-respiratory oxygen utilization in adult worms, but with different proportions among parasite sexes. Analyses of oxygen utilization pathways revealed that respiratory rates were high in male worms, which contrast with high non-respiratory rates in females, regardless nutritional sources. Interestingly, mitochondrial complex I-III activity was higher than complex IV specifically in females. We also observed sexual preferences in substrate utilization to sustain hydrogen peroxide production towards glucose in females, and glutamine in male worms. Despite strikingly high oxidant levels and hydrogen peroxide production rates, female worms were more resistant to a pro-oxidant challenge than male parasites. The data presented here indicate that sexual preferences in nutrient metabolism in adult S. mansoni worms regulate oxygen utilization and reactive oxygen species production, which may differently contribute

  5. Persistent hepatitis C virus (HCV) infection impairs HCV-specific cytotoxic T cell reactivity through Mcl-1/Bim imbalance due to CD127 down-regulation.

    PubMed

    Larrubia, J R; Lokhande, M U; García-Garzón, S; Miquel, J; González-Praetorius, A; Parra-Cid, T; Sanz-de-Villalobos, E

    2013-02-01

    In persistent hepatitis C virus (HCV) infection, HCV-specific cytotoxic T lymphocyte (CTL) reactivity is impaired and this affects HCV control. Interleukin-7 receptor (CD127) expression on these cells could regulate CTL reactivity through Mcl-1/Bim balance modulation. Bim is a pro-apoptotic molecule blocked by the action of Mcl-1. Mcl-1/Bim expression and T cell reactivity on HCV-specific CTLs were compared according to CD127 phenotype. Peripheral blood lymphocytes (PBL) from HLA-A2(+) HCV(+) patients were obtained. HCV-specific CTLs were visualized by staining PBL with anti-CD8 and HLA-A2/peptide pentameric complexes (pentamer). Mcl-1/Bim/CD127 phenotype of HCV-specific CTLs was tested by staining detectable CD8(+)/pentamer(+) cells with anti-Mcl-1/Bim/CD127 antibodies. HCV-specific CTL proliferation ability after specific in vitro challenge was tested in the presence and absence of pancaspase inhibitor z-VAD-fmk. All stained cells were analysed by flow cytometry. CD127(low)-expressing HCV-specific CTLs associated with high HCV viraemia, while CD127(high) correlated with undetectable viral loads (P < 0.001). Directly ex vivo, pentamer(+) cell frequency was similar according to CD127 expression level. Nevertheless, CD127(low) pentamer(+) cell proliferation after specific in vitro challenge was impaired (P < 0.05), although this was corrected by z-VAD-fmk treatment (P < 0.05). Mcl-1 expression was low directly ex vivo (P < 0.01), and Bim was up-regulated after antigen encounter (P < 0.05) of CD127(low) pentamer(+) cells. The ex vivo difference between Mcl-1 and Bim expression on pentamer(+) cells correlated positively with CD127 expression level (P < 0.001) and with pentamer(+) cell reactivity (P < 0.05). In summary, a low ex vivo Mcl-1 expression and Bim up-regulation after antigen encounter are involved in CD127(low) HCV-specific CTL hyporeactivity during chronic infection, but it can be overcome by apoptosis blockade.

  6. Increased reactive oxygen species production down-regulates peroxisome proliferator-activated alpha pathway in C2C12 skeletal muscle cells.

    PubMed

    Cabrero, Agatha; Alegret, Marta; Sanchez, Rosa M; Adzet, Tomas; Laguna, Juan C; Carrera, Manuel Vazquez

    2002-03-22

    Generation of reactive oxygen species may contribute to the pathogenesis of diseases involving intracellular lipid accumulation. To explore the mechanisms leading to these pathologies we tested the effects of etomoxir, an inhibitor of carnitine palmitoyltransferase I which contains a fatty acid-derived structure, in C2C12 skeletal muscle cells. Etomoxir treatment for 24 h resulted in a down-regulation of peroxisome proliferator-activated receptor alpha (PPARalpha) mRNA expression, achieving an 87% reduction at 80 microm etomoxir. The mRNA levels of most of the PPARalpha target genes studied were reduced at 100 microm etomoxir. By using several inhibitors of de novo ceramide synthesis and C(2)-ceramide we showed that they were not involved in the effects of etomoxir. Interestingly, the addition of triacsin C, a potent inhibitor of acyl-CoA synthetase, to etomoxir-treated C2C12 skeletal muscle cells did not prevent the down-regulation in PPARalpha mRNA levels, suggesting that the active form of the drug, etomoxir-CoA, was not involved. Given that saturated fatty acids may generate reactive oxygen species (ROS), we determined whether the addition of etomoxir resulted in ROS generation. Etomoxir increased ROS production and the activity of the well known redox transcription factor NF-kappaB. In the presence of the pyrrolidine dithiocarbamate, a potent antioxidant and inhibitor of NF-kappaB activity, etomoxir did not down-regulate PPARalpha mRNA in C2C12 skeletal muscle cells. These results indicate that ROS generation and NF-kappaB activation are responsible for the down-regulation of PPARalpha and may provide a new mechanism by which intracellular lipid accumulation occurs in skeletal muscle cells.

  7. Screen for reactivation of MeCP2 on the inactive X chromosome identifies the BMP/TGF-β superfamily as a regulator of XIST expression.

    PubMed

    Sripathy, Smitha; Leko, Vid; Adrianse, Robin L; Loe, Taylor; Foss, Eric J; Dalrymple, Emily; Lao, Uyen; Gatbonton-Schwager, Tonibelle; Carter, Kelly T; Payer, Bernhard; Paddison, Patrick J; Grady, William M; Lee, Jeannie T; Bartolomei, Marisa S; Bedalov, Antonio

    2017-02-14

    Rett syndrome (RS) is a debilitating neurological disorder affecting mostly girls with heterozygous mutations in the gene encoding the methyl-CpG-binding protein MeCP2 on the X chromosome. Because restoration of MeCP2 expression in a mouse model reverses neurologic deficits in adult animals, reactivation of the wild-type copy of MeCP2 on the inactive X chromosome (Xi) presents a therapeutic opportunity in RS. To identify genes involved in MeCP2 silencing, we screened a library of 60,000 shRNAs using a cell line with a MeCP2 reporter on the Xi and found 30 genes clustered in seven functional groups. More than half encoded proteins with known enzymatic activity, and six were members of the bone morphogenetic protein (BMP)/TGF-β pathway. shRNAs directed against each of these six genes down-regulated X-inactive specific transcript (XIST), a key player in X-chromosome inactivation that encodes an RNA that coats the silent X chromosome, and modulation of regulators of this pathway both in cell culture and in mice demonstrated robust regulation of XIST. Moreover, we show that Rnf12, an X-encoded ubiquitin ligase important for initiation of X-chromosome inactivation and XIST transcription in ES cells, also plays a role in maintenance of the inactive state through regulation of BMP/TGF-β signaling. Our results identify pharmacologically suitable targets for reactivation of MeCP2 on the Xi and a genetic circuitry that maintains XIST expression and X-chromosome inactivation in differentiated cells.

  8. Coordinated control of wind generation and energy storage for power system frequency regulation

    NASA Astrophysics Data System (ADS)

    Baone, Chaitanya Ashok

    Large-scale centralized synchronous generators have long been the primary actors in exercising active power and frequency control, and much of the existing grid control framework is predicated upon their dynamic terminal characteristics. Important among these characteristics is the inertia of such generators. These play key roles in determining the electromechanical stability of the electric power grid. Modern wind generator systems are partially or fully connected to the grid through power electronic interfaces, and hence do not present the same level of inertial coupling. The absence of inertial frequency response from modern wind generator systems is a topic of growing concern in power engineering practice, as the penetration of wind generation is expected to grow dramatically in the next few years. Solutions proposed in the literature have sought to address this problem by seeking to mimic the inherent inertial response characteristics of traditional synchronous generators via control loops added to wind generators. Recent literature has raised concerns regarding this approach, and the work here will further examine its shortcomings, motivating approaches that seek to optimally design for the characteristics of the equipment exercising the control, rather than forcing new technologies to mimic the characteristics of synchronous machines. In particular, this work will develop a new approach to power system frequency regulation, with features suited to distributed energy storage devices such as grid-scale batteries and wind turbine speed and blade pitch control. The dynamic characteristics of these new technologies are treated along with existing mechanisms, such as synchronous machine governor control, to develop a comprehensive multi-input control design approach. To make the method practically feasible for geographically distributed power systems, an observer-based distributed control design utilizing phasor measurement unit (PMU) signals along with local

  9. Export of reactive nitrogen from coal-fired power plants in the U.S.: Estimates from a plume-in-grid modeling study

    NASA Astrophysics Data System (ADS)

    Vijayaraghavan, Krish; Zhang, Yang; Seigneur, Christian; Karamchandani, Prakash; Snell, Hilary E.

    2009-02-01

    The export of reactive nitrogen (nitrogen oxides and their oxidation products, collectively referred to as NOy) from coal-fired power plants in the U.S. to the rest of the world could have a significant global contribution to ozone. Traditional Eulerian gridded air quality models cannot characterize accurately the chemistry and transport of plumes from elevated point sources such as power plant stacks. A state-of-the-science plume-in-grid (PinG) air quality model, a reactive plume model embedded in an Eulerian gridded model, is used to estimate the export of NOy from 25 large coal-fired power plants in the U.S. (in terms of NOx and SO2 emissions) in July 2001 to the global atmosphere. The PinG model used is the Community Multiscale Air Quality Model with Advanced Plume Treatment (CMAQ-APT). A benchmark simulation with only the gridded model, CMAQ, is also conducted for comparison purposes. The simulations with and without advanced plume treatment show differences in the calculated export of NOy from the 25 plants considered reflecting the effect of using a detailed and explicit treatment of plume transport and chemistry. The advanced plume treatment results in 31% greater simulated export of NOy compared to the purely grid-based modeling approach. The export efficiency of NOy (the fraction of NOy emitted that is exported) is predicted to be 21% without APT and 27% with APT. When considering only export through the eastern boundary across the Atlantic, CMAQ-APT predicts that the export efficiency is 24% and that 2% of NOy is exported as NOx, 49% as inorganic nitrate, and 25% as PAN. These results are in reasonably good agreement with an analysis reported in the literature of aircraft measurements over the North Atlantic.

  10. The Optimisation Of Array Power Regulators (APRS) For Solar Observation Platforms And Future Electrical Power System (EPS) Through The B2R Topology

    NASA Astrophysics Data System (ADS)

    Alcindor, Peter; Bard, Frederic; Kiewe, Bernhard; Tonicello, Ferdinando; Mourra, Oliver

    2011-10-01

    Power regulators for solar observation platforms must be compatible with widely varying solar array voltages due to the large temperature variations resulting from contrasting sun distances or sun/eclipse cycling close to the sun. To produce a 28V regulated power bus for scientific instruments a Buck topology is necessary (today's qualified technology). Analysis will show that front end of Power Conditioning Units (PCUs) must work over voltage ranges of almost twice that of Earth orbiting spacecraft. This paper is targeted at missions that operate over the full mission trajectory and in particular at far sun distances where array sizing is performed. Performance degradation associated with Buck topologies operating over wide voltage ranges is established and the importance of reducing the solar array voltage to a minimum is highlighted. Finally, attention is drawn to how the Buck-Boost Regulator (B2R) topology, currently under development, provides a potential solution to this and other problems.

  11. Single Event Transients in Voltage Regulators for FPGA Power Supply Applications

    NASA Technical Reports Server (NTRS)

    Poivey, Christian; Sanders, Anthony; Kim, Hak; Phan, Anthony; Forney, Jim; LaBel, Kenneth A.; Karsh, Jeremy; Pursley, Scott; Kleyner, Igor; Katz, Richard

    2006-01-01

    As with other bipolar analog devices, voltage regulators are known to be sensitive to single event transients (SET). In typical applications, large output capacitors are used to provide noise immunity. Therefore, since SET amplitude and duration are generally small, they are often of secondary importance due to this capacitance filtering. In low voltage applications, however, even small SET are a concern. Over-voltages may cause destructive conditions. Under-voltages may cause functional interrupts and may also trigger electrical latchup conditions. In addition, internal protection circuits which are affected by load as well as internal thermal effects can also be triggered from heavy ions, causing dropouts or shutdown ranging from milliseconds to seconds. In the case of FPGA power supplies applications, SETS are critical. For example, in the case of Actel FPGA RTAX family, core power supply voltage is 1.5V. Manufacturer specifies an absolute maximum rating of 1.6V and recommended operating conditions between 1.425V and 1.575V. Therefore, according to the manufacturer, any transient of amplitude greater than 75 mV can disrupt normal circuit functions, and overvoltages greater than 100 mV may damage the FPGA. We tested five low dropout voltage regulators for SET sensitivity under a large range of circuit application conditions.

  12. The role of perceived control in physiological reactivity: self-efficacy and incentive value as regulators of cardiovascular adjustment.

    PubMed

    Sanz, A; Villamarín, F

    2001-06-01

    The aim of this study was to verify the influence of self-efficacy and incentive value on cardiovascular reactivity. Ninety-six subjects were randomly assigned to four experimental groups in each of which the self-efficacy (high or low) and incentive value (high or low) were modified in relation to a mental arithmetic task. Subjects were led to believe that failure in this behaviour would result in the appearance of an aversive stimulus. Heart rate, systolic and diastolic blood pressure, pulse pressure and skin temperature were all recorded throughout task performance, and at two given moments prior to the task, in order to establish baseline values. Subjects with high self-efficacy experienced a smaller increase in heart rate and systolic pressure, a greater increase in diastolic pressure, greater reduction in skin temperature and a reduction in pulse pressure during task performance. The effects were moderated by the incentive value in such a way that the effects of self-efficacy on cardiovascular reactivity were stronger when the consequences of task failure were perceived as highly relevant (high incentive value).

  13. Ethylene negatively regulates transcript abundance of ROP-GAP rheostat-encoding genes and affects apoplastic reactive oxygen species homeostasis in epicarps of cold stored apple fruits.

    PubMed

    Zermiani, Monica; Zonin, Elisabetta; Nonis, Alberto; Begheldo, Maura; Ceccato, Luca; Vezzaro, Alice; Baldan, Barbara; Trentin, Annarita; Masi, Antonio; Pegoraro, Marco; Fadanelli, Livio; Teale, William; Palme, Klaus; Quintieri, Luigi; Ruperti, Benedetto

    2015-12-01

    Apple (Malus×domestica Borkh) fruits are stored for long periods of time at low temperatures (1 °C) leading to the occurrence of physiological disorders. 'Superficial scald' of Granny Smith apples, an economically important ethylene-dependent disorder, was used as a model to study relationships among ethylene action, the regulation of the ROP-GAP rheostat, and maintenance of H2O2 homeostasis in fruits during prolonged cold exposure. The ROP-GAP rheostat is a key module for adaptation to low oxygen in Arabidopsis through Respiratory Burst NADPH Oxidase Homologs (RBOH)-mediated and ROP GTPase-dependent regulation of reactive oxygen species (ROS) homeostasis. Here, it was shown that the transcriptional expression of several components of the apple ROP-GAP machinery, including genes encoding RBOHs, ROPs, and their ancillary proteins ROP-GEFs and ROP-GAPs, is coordinately and negatively regulated by ethylene in conjunction with the progressive impairment of apoplastic H2O2 homeostatic levels. RNA sequencing analyses showed that several components of the known ROP- and ROS-associated transcriptional networks are regulated along with the ROP-GAP rheostat in response to ethylene perception. These findings may extend the role of the ROP-GAP rheostat beyond hypoxic responses and suggest that it may be a functional regulatory node involved in the integration of ethylene and ROS signalling pathways in abiotic stress.

  14. Adaptive PI controller to voltage regulation in power systems: STATCOM as a case study.

    PubMed

    Tavana, Mohammad Reza; Khooban, Mohammad-Hassan; Niknam, Taher

    2017-01-01

    Static synchronous compensator (STATCOM) provides the means to improve quality and reliability of a power system as it has the functional capability to handle dynamic disturbances, such as transient stability and power oscillation damping as well as to providing voltage regulation. In this paper, a robust adaptive PI-based optimal fuzzy control strategy is proposed to control a STATCOM used in distribution systems. The proposed intelligent strategy is based on a combination of a new General Type-II Fuzzy Logic (GT2FL) with a simple heuristic algorithm named Teaching Learning Based Optimization (TLBO) Algorithm. The proposed framework optimally tunes parameters of a Proportional-Integral (PI) controller which, similar to most of other researchers regarding control of STATCOM, are in charge of controlling the device. The proposed controller guaranties robustness and stability against uncertainties caused by external disturbances or ever-changing nature of the power systems. The TLBO optimizes the parameters of the controller as well as the input and output membership functions. To validate the efficiency of the proposed controller, the obtained simulation results are compared with those of the two most recent researches applied in this field, namely, conventional Proportional Integral (PI) controller and Optimal Fuzzy PI (OFPI) controller. Results demonstrate the successfulness and effectiveness of the proposed online-TLBO General Type-2 Fuzzy PI (OGT2FPI) controller and its superiority over conventional approaches.

  15. Modified DSTATCOM Topology with Reduced DC Link Voltage for Reactive and Harmonic Power Compensation of Unbalanced Nonlinear Load in Distribution System

    NASA Astrophysics Data System (ADS)

    Geddada, Nagesh; Karanki, Srinivas B.; Mishra, Mahesh K.

    2014-06-01

    This paper proposes a modified four-leg distribution static compensator (DSTATCOM) topology for compensation of unbalanced and nonlinear loads in three-phase four-wire distribution system. DSTATCOM, connected in parallel to the load, supplies reactive and harmonic powers demanded by unbalanced nonlinear loads. In this proposed topology, the voltage source inverter (VSI) of DSTATCOM is connected to point of common coupling (point of interconnection of source, load, DSTATCOM) through interface inductor and series capacitance, unlike the conventional topology which consists of interface inductor alone. Load compensation with a lower value of input DC link voltage of VSI is possible in this modified topology compared to conventional topology. A comparative study on modified and conventional topologies in terms of voltage rating of inverter power switches, switching losses in VSI and power rating of input DC capacitor of VSI is presented. The detailed design aspects of DC link capacitor and interface series capacitor are also presented. The reference filter currents are generated using instantaneous symmetrical component theory and are tracked using hysteresis current control technique. A detailed simulation study is carried out, to compare the compensation performances of conventional, modified topologies using PSCAD simulator and experimental studies are done to validate the simulation results.

  16. Trait Anger Management Style Moderates Effects of Actual (″State″) Anger Regulation on Symptom-Specific Reactivity and Recovery Among Chronic Low Back Pain Patients

    PubMed Central

    Burns, John W.; Holly, Amanda; Quartana, Phillip; Wolff, Brandy; Gray, Erika; Bruehl, Stephen

    2013-01-01

    Objectives We examined whether “state” anger regulation—inhibition or expression—among chronic low back pain (CLBP) patients would affect lower paraspinal (LP) muscle tension following anger-induction, and whether these effects were moderated by trait anger management style. Method Eighty-four CLBP patients underwent harassment, then they regulated anger under one of two conditions: half expressed anger by telling stories about people depicted in pictures, whereas half inhibited anger by only describing objects appearing in the same pictures. They completed the anger-out and anger-in subscales (AOS; AIS) of the anger expression inventory. Results General Linear Model procedures were used to test anger regulation condition by AOS/AIS by period interactions for physiological indexes. Significant three-way interactions were found such that: a) high trait anger-out patients in the inhibition condition appeared to show the greatest LP reactivity during the inhibition period followed by the slowest recovery; b) high trait anger-out patients in the expression condition appeared to show the greatest systolic blood pressure (SBP) reactivity during the expression period followed by rapid recovery. Conclusions Results implicate LP muscle tension as a potential physiological mechanism that links the actual inhibition of anger following provocation to chronic pain severity among CLBP patients. Results also highlight the importance of mismatch situations for patients who typically regulate anger by expressing it. These CLBP patients may be at particular risk for elevated pain severity if circumstances at work or home regularly dictate that they should inhibit anger expression. PMID:18725429

  17. NDE evaluation of the intergranular corrosion susceptibility of a 2205 duplex stainless steel using thermoelectric power and double loop electrochemical potentiokinetic reactivation methods

    NASA Astrophysics Data System (ADS)

    Ortiz, N.; Carreón, H.; Ruiz, A.

    2013-01-01

    There is a need for a nondestructive technique to assess rapidly and with confidence the degree of sensitization (DOS) in duplex stainless steel (DSS). In this investigation, we present the use of thermoelectric power (TEP) measurements as nondestructive method for the determination of DOS in isothermally aged 2205 DSS at 700°C for different aging times. The DOS of the aged samples was first established by performing the double loop electrochemical potentiokinetic reactivation (DL-EPR) test. The microstructural evolution was evaluated by scanning electron microscopy (SEM). Experimental results indicate that TEP coefficient is sensitive to gradual microstructural changes produced by thermal aging and can be used to monitor IGC sensitization of 2205 duplex stainless steel.

  18. Moderate versus severe early life stress: Associations with stress reactivity and regulation in 10–12-year-old children

    PubMed Central

    Gunnar, Megan R.; Frenn, Kristin; Wewerka, Sandi S.; Van Ryzin, Mark J.

    2009-01-01

    Summary Early life stress (ELS) is expected to increase reactivity of the hypothalamic–pituitary–adrenocortical (HPA) axis; however, several recent studies have shown diminished cortisol reactivity among adults and children with ELS exposure. The goal of this study was to examine cortisol activity in 10–12-year-old internationally adopted children to determine if moderate and severe ELS have different impacts on the HPA axis. Salivary cortisol and two measures of autonomic activity were collected in response to the Trier Social Stress Test for Children (TSST-C). Three groups reflecting moderate, severe, and little ELS were studied: early adopted children who came predominantly from foster care overseas (early adopted/foster care (EA/FC), n = 44), later adopted children cared for predominantly in orphanages overseas (late adopted/post-institutionalized (LA/PI), n = 42) and non-adopted (NA) children reared continuously by their middle- to upper-income parents in the United States (n = 38). Diminished cortisol activity was noted for the EA/FC group (moderate ELS), while the LA/PI group (severe ELS) did not differ from the NA group. Overall, few children showed cortisol elevations to the TSST-C in any group. The presence/absence of severe growth delay at adoption proved to be a critical predictive factor in cortisol activity. Regardless of growth delay, however, LA/PI children exhibited higher sympathetic tone than did NA children. These results suggest that moderate ELS is associated with diminished cortisol activity; however, marked individual differences in cortisol activity among the LA/PI children suggest that child factors modify the impact of severe ELS. Lack of effects of severe ELS even for growth delayed children may reflect the restorative effects of adoption or the generally low responsiveness of this age group to the TSST-C. PMID:18835102

  19. Piwil2 is reactivated by HPV oncoproteins and initiates cell reprogramming via epigenetic regulation during cervical cancer tumorigenesis

    PubMed Central

    Feng, Dingqing; Yan, Keqin; Zhou, Ying; Liang, Haiyan; Liang, Jing; Zhao, Weidong; Dong, Zhongjun; Ling, Bin

    2016-01-01

    The human papillomavirus (HPV) oncoproteins E6 and E7 are risk factors that are primarily responsible for the initiation and progression of cervical cancer, and they play a key role in immortalization and transformation by reprogramming differentiating host epithelial cells. It is unclear how cervical epithelial cells transform into tumor-initiating cells (TICs). Here, we observed that the germ stem cell protein Piwil2 is expressed in pre-cancerous and malignant lesions of the cervix and cervical cancer cell lines with the exception of the non-HPV-infected C33a cell line. Knockdown of Piwil2 by shRNA led to a marked reduction in proliferation and colony formation, in vivo tumorigenicity, chemo-resistance, and the proportion of cancer stem-like cells. In contrast, Piwil2 overexpression induced malignant transformation of HaCaT cells and the acquisition of tumor-initiating capabilities. Gene-set enrichment analysis revealed embryonic stem cell (ESC) identity, malignant biological behavior, and specifically, activation targets of the cell reprogramming factors c-Myc, Klf4, Nanog, Oct4, and Sox2 in Piwil2-overexpressing HaCaT cells. We further confirmed that E6 and E7 reactivated Piwil2 and that E6 and E7 overexpression resulted in a similar gene-set enrichment pattern as Piwil2 overexpression in HaCaT cells. Moreover, Piwil2 overexpression or E6 and E7 activation induced H3K9 acetylation but reduced H3K9 trimethylation, which contributed to the epigenetic reprogramming and ESC signature maintenance, as predicted previously. Our study demonstrates that Piwil2, reactivated by the HPV oncoproteins E6 and E7, plays an essential role in the transformation of cervical epithelial cells to TICs via epigenetics-based cell reprogramming. PMID:27602489

  20. Less Empathic and More Reactive: The Different Impact of Childhood Maltreatment on Facial Mimicry and Vagal Regulation.

    PubMed

    Ardizzi, Martina; Umiltà, Maria Alessandra; Evangelista, Valentina; Di Liscia, Alessandra; Ravera, Roberto; Gallese, Vittorio

    Facial mimicry and vagal regulation represent two crucial physiological responses to others' facial expressions of emotions. Facial mimicry, defined as the automatic, rapid and congruent electromyographic activation to others' facial expressions, is implicated in empathy, emotional reciprocity and emotions recognition. Vagal regulation, quantified by the computation of Respiratory Sinus Arrhythmia (RSA), exemplifies the autonomic adaptation to contingent social cues. Although it has been demonstrated that childhood maltreatment induces alterations in the processing of the facial expression of emotions, both at an explicit and implicit level, the effects of maltreatment on children's facial mimicry and vagal regulation in response to facial expressions of emotions remain unknown. The purpose of the present study was to fill this gap, involving 24 street-children (maltreated group) and 20 age-matched controls (control group). We recorded their spontaneous facial electromyographic activations of corrugator and zygomaticus muscles and RSA responses during the visualization of the facial expressions of anger, fear, joy and sadness. Results demonstrated a different impact of childhood maltreatment on facial mimicry and vagal regulation. Maltreated children did not show the typical positive-negative modulation of corrugator mimicry. Furthermore, when only negative facial expressions were considered, maltreated children demonstrated lower corrugator mimicry than controls. With respect to vagal regulation, whereas maltreated children manifested the expected and functional inverse correlation between RSA value at rest and RSA response to angry facial expressions, controls did not. These results describe an early and divergent functional adaptation to hostile environment of the two investigated physiological mechanisms. On the one side, maltreatment leads to the suppression of the spontaneous facial mimicry normally concurring to empathic understanding of others' emotions. On

  1. Less Empathic and More Reactive: The Different Impact of Childhood Maltreatment on Facial Mimicry and Vagal Regulation

    PubMed Central

    Ardizzi, Martina; Umiltà, Maria Alessandra; Evangelista, Valentina; Di Liscia, Alessandra; Ravera, Roberto; Gallese, Vittorio

    2016-01-01

    Facial mimicry and vagal regulation represent two crucial physiological responses to others’ facial expressions of emotions. Facial mimicry, defined as the automatic, rapid and congruent electromyographic activation to others’ facial expressions, is implicated in empathy, emotional reciprocity and emotions recognition. Vagal regulation, quantified by the computation of Respiratory Sinus Arrhythmia (RSA), exemplifies the autonomic adaptation to contingent social cues. Although it has been demonstrated that childhood maltreatment induces alterations in the processing of the facial expression of emotions, both at an explicit and implicit level, the effects of maltreatment on children’s facial mimicry and vagal regulation in response to facial expressions of emotions remain unknown. The purpose of the present study was to fill this gap, involving 24 street-children (maltreated group) and 20 age-matched controls (control group). We recorded their spontaneous facial electromyographic activations of corrugator and zygomaticus muscles and RSA responses during the visualization of the facial expressions of anger, fear, joy and sadness. Results demonstrated a different impact of childhood maltreatment on facial mimicry and vagal regulation. Maltreated children did not show the typical positive-negative modulation of corrugator mimicry. Furthermore, when only negative facial expressions were considered, maltreated children demonstrated lower corrugator mimicry than controls. With respect to vagal regulation, whereas maltreated children manifested the expected and functional inverse correlation between RSA value at rest and RSA response to angry facial expressions, controls did not. These results describe an early and divergent functional adaptation to hostile environment of the two investigated physiological mechanisms. On the one side, maltreatment leads to the suppression of the spontaneous facial mimicry normally concurring to empathic understanding of others

  2. Peptide microarray analysis of substrate specificity of the transmembrane Ser/Thr kinase KPI-2 reveals reactivity with cystic fibrosis transmembrane conductance regulator and phosphorylase.

    PubMed

    Wang, Hong; Brautigan, David L

    2006-11-01

    Human lemur (Lmr) kinases are predicted to be Tyr kinases based on sequences and are related to neurotrophin receptor Trk kinases. This study used homogeneous recombinant KPI-2 (Lmr2, LMTK2, Cprk, brain-enriched protein kinase) kinase domain and a library of 1,154 peptides on a microarray to analyze substrate specificity. We found that KPI-2 is strictly a Ser/Thr kinase that reacts with Ser either preceded by or followed by Pro residues but unlike other Pro-directed kinases does not strictly require an adjacent Pro residue. The most reactive peptide in the library corresponds to Ser-737 of cystic fibrosis transmembrane conductance regulator, and the recombinant R domain of cystic fibrosis transmembrane conductance regulator was a preferred substrate. Furthermore the KPI-2 kinase phosphorylated peptides corresponding to the single site in phosphorylase and purified phosphorylase b, making this only the second known phosphorylase b kinase. Phosphorylase was used as a specific substrate to show that KPI-2 is inhibited in living cells by addition of nerve growth factor or serum. The results demonstrate the utility of the peptide library to probe specificity and discover kinase substrates and offer a specific assay that reveals hormonal regulation of the activity of this unusual transmembrane kinase.

  3. Grape seed proanthocyanidins reactivate silenced tumor suppressor genes in human skin cancer cells by targeting epigenetic regulators

    SciTech Connect

    Vaid, Mudit; Prasad, Ram; Singh, Tripti; Jones, Virginia; Katiyar, Santosh K.

    2012-08-15

    Grape seed proanthocyanidins (GSPs) have been shown to have anti-skin carcinogenic effects in in vitro and in vivo models. However, the precise epigenetic molecular mechanisms remain unexplored. This study was designed to investigate whether GSPs reactivate silenced tumor suppressor genes following epigenetic modifications in skin cancer cells. For this purpose, A431 and SCC13 human squamous cell carcinoma cell lines were used as in vitro models. The effects of GSPs on DNA methylation, histone modifications and tumor suppressor gene expressions were studied in these cell lines using enzyme activity assays, western blotting, dot-blot analysis and real-time polymerase chain reaction (RT-PCR). We found that treatment of A431 and SCC13 cells with GSPs decreased the levels of: (i) global DNA methylation, (ii) 5-methylcytosine, (iii) DNA methyltransferase (DNMT) activity and (iv) messenger RNA (mRNA) and protein levels of DNMT1, DNMT3a and DNMT3b in these cells. Similar effects were noted when these cancer cells were treated identically with 5-aza-2′-deoxycytidine, an inhibitor of DNA methylation. GSPs decreased histone deacetylase activity, increased levels of acetylated lysines 9 and 14 on histone H3 (H3-Lys 9 and 14) and acetylated lysines 5, 12 and 16 on histone H4, and reduced the levels of methylated H3-Lys 9. Further, GSP treatment resulted in re-expression of the mRNA and proteins of silenced tumor suppressor genes, RASSF1A, p16{sup INK4a} and Cip1/p21. Together, this study provides a new insight into the epigenetic mechanisms of GSPs and may have significant implications for epigenetic therapy in the treatment/prevention of skin cancers in humans. -- Highlights: ►Epigenetic modulations have been shown to have a role in cancer risk. ►Proanthocyanidins decrease the levels of DNA methylation and histone deacetylation. ►Proanthocyanidins inhibit histone deacetylase activity in skin cancer cells. ►Proanthocyanidins reactivate tumor suppressor genes in skin

  4. Cutting edge: FYCO1 recruitment to dectin-1 phagosomes is accelerated by light chain 3 protein and regulates phagosome maturation and reactive oxygen production.

    PubMed

    Ma, Jun; Becker, Courtney; Reyes, Christopher; Underhill, David M

    2014-02-15

    L chain 3 (LC3)-associated phagocytosis is a process in which LC3, a protein canonically involved in engulfing intracellular materials (autophagy), is recruited to traditional phagosomes during internalization of extracellular payloads. LC3's association with phagosomes has been implicated in regulating microbial killing, Ag processing, and phagosome maturation; however, the mechanism by which LC3 influences these processes has not been clear. In this study, we report that FYVE and coiled-coil domain containing 1 (FYCO1), a protein previously implicated in autophagosome trafficking, is recruited directly by LC3 to Dectin-1 phagosomes. During LC3-associated phagocytosis, FYCO1 recruitment facilitates maturation of early p40phox(+) phagosomes into late LAMP1(+) phagosomes. When FYCO1 is lacking, phagosomes stay p40phox(+) longer and produce more reactive oxygen.

  5. Surfactant protein D, Club cell protein 16, Pulmonary and activation-regulated chemokine, C-reactive protein, and Fibrinogen biomarker variation in chronic obstructive lung disease.

    PubMed

    Lock-Johansson, Sofie; Vestbo, Jørgen; Sorensen, Grith Lykke

    2014-11-25

    Chronic obstructive pulmonary disease (COPD) is a multifaceted condition that cannot be fully described by the severity of airway obstruction. The limitations of spirometry and clinical history have prompted researchers to investigate a multitude of surrogate biomarkers of disease for the assessment of patients, prediction of risk, and guidance of treatment. The aim of this review is to provide a comprehensive summary of observations for a selection of recently investigated pulmonary inflammatory biomarkers (Surfactant protein D (SP-D), Club cell protein 16 (CC-16), and Pulmonary and activation-regulated chemokine (PARC/CCL-18)) and systemic inflammatory biomarkers (C-reactive protein (CRP) and fibrinogen) with COPD. The relevance of these biomarkers for COPD is discussed in terms of their biological plausibility, their independent association to disease and hard clinical outcomes, their modification by interventions, and whether changes in clinical outcomes are reflected by changes in the biomarker.

  6. Albumin overload down-regulates integrin-β1 through reactive oxygen species-endoplasmic reticulum stress pathway in podocytes.

    PubMed

    Cheng, Yu-Chi; Chen, Chien-An; Chang, Jer-Ming; Chen, Hung-Chun

    2015-08-01

    Proteinuria is a major hallmark of glomerular nephropathy and endoplasmic reticulum (ER) stress plays an important role in glomerular nephropathy. The protein levels of integrin-β1 in podocytes are found to be negative correlation with amount of proteinuria. This study investigated whether urinary protein, particularly albumin, induced ER stress that consequently reduced integrin-β1 expression. All experiments were performed using primary cultured rat podocyte. Protein and mRNA expression were measured by western blotting and semiquantified reverse transcriptase polymerase chain reaction. Albumin uptake was found at 1 h after albumin addition. Albumin reduced precursor and mature forms of integrin-β1, but did not change mRNA levels of integrin-β1. Albumin induced reactive oxygen species (ROS) generation and ER stress. Antioxidant (N-acetylcysteine) suppressed albumin-induced ER stress and decrements in precursor and mature forms of integrin-β1. Then, ER stress inhibitors (4-phenylbutyrate and salubrinal) also inhibited albumin-induced decrements in precursor and mature forms of integrin-β1. The potent ER stress inducers (thapsigargin and tunicamycin) directly decreased precursor and mature forms of integrin-β1 and led appearance of unglycosylated core protein of integrin-β1. Our results show that in proteinuric disease, albumin decreases precursor and mature forms of integrin-β1 through ROS-ER stress pathway in podocytes.

  7. IL-17 induces reactive astrocytes and up-regulation of vascular endothelial growth factor (VEGF) through JAK/STAT signaling

    PubMed Central

    You, Tao; Bi, Yihui; li, Jun; Zhang, Mingkai; Chen, Xuezhou; Zhang, Keke; Li, Jun

    2017-01-01

    Spinal cord injury is a grave neurological disability resulting in neuron degeneration and permanent paralysis. The inflammation triggered by the injury would promote the spinal cord lesion in turn. Activated astrocytes during inflammatory response could promote glial scar formation and contribute to the progression of the spinal cord injury. Interleukin 17 (IL-17) was upregulated in inflammatory responses to contusion or compression of the spinal cord. in this study, IL-17 could induce reactive astrocytes which was indicated by a well-known hallmark glial fibrillary acidic protein (GFAP) in vitro and in vivo. Moreover, we demonstrated that the upregulation of VEGF was induced by IL-17 human astrocytoma cells. In our further investigation, IL-17 induced the expression of VEGF in spinal cord injury by activating JAK/STAT signaling pathway both in vitro and in vivo. In addition, we also found that IL-17 significantly changed tissue preservation and residual urine volumes and blood-spinal cord-barrier integrity in vivo. This newly found IL-17-JAK/STAT-VEGF axis improves our understanding of the molecular mechanism of spinal cord injury during inflammatory response and provides another potential target of spinal cord injury. PMID:28281545

  8. A Decentralized Multivariable Robust Adaptive Voltage and Speed Regulator for Large-Scale Power Systems

    NASA Astrophysics Data System (ADS)

    Okou, Francis A.; Akhrif, Ouassima; Dessaint, Louis A.; Bouchard, Derrick

    2013-05-01

    This papter introduces a decentralized multivariable robust adaptive voltage and frequency regulator to ensure the stability of large-scale interconnnected generators. Interconnection parameters (i.e. load, line and transormer parameters) are assumed to be unknown. The proposed design approach requires the reformulation of conventiaonal power system models into a multivariable model with generator terminal voltages as state variables, and excitation and turbine valve inputs as control signals. This model, while suitable for the application of modern control methods, introduces problems with regards to current design techniques for large-scale systems. Interconnection terms, which are treated as perturbations, do not meet the common matching condition assumption. A new adaptive method for a certain class of large-scale systems is therefore introduces that does not require the matching condition. The proposed controller consists of nonlinear inputs that cancel some nonlinearities of the model. Auxiliary controls with linear and nonlinear components are used to stabilize the system. They compensate unknown parametes of the model by updating both the nonlinear component gains and excitation parameters. The adaptation algorithms involve the sigma-modification approach for auxiliary control gains, and the projection approach for excitation parameters to prevent estimation drift. The computation of the matrix-gain of the controller linear component requires the resolution of an algebraic Riccati equation and helps to solve the perturbation-mismatching problem. A realistic power system is used to assess the proposed controller performance. The results show that both stability and transient performance are considerably improved following a severe contingency.

  9. Coal-fired power generaion, new air quality regulations, and future U.S. coal production

    USGS Publications Warehouse

    Attanasi, E.D.; Root, D.H.

    1999-01-01

    Tighter new regulation of stack gas emissions and competition in power generation are driving electrical utilities to demand cleaner, lower sulfur coal. Historical data on sulfur content of produced coals shows little variability in coal quality for individual mines and individual coal-producing counties over relatively long periods of time. If coal-using power generators follow the compliance patterns established in Phase I of the 1990 Clean Air Act Amendments, then the industry's response to the tighter Phase II emissions standards will result in large amounts of coal production shifting from higher sulfur areas to areas with lower cost low sulfur coal. One reason this shift will likely occur is that currently only 30% of U.S. coal-fired electrical generating capacity is equipped with flue-gas scrubbers. In 1995, coal mines in the higher sulfur areas of the Illinois Basin and Northern and Central Appalachia employed 78% of all coal miners (>70,000 miners). A substantial geographical redistribution of the nation's coal supplies will likely lead to economic dislocations that will reach beyond local coal-producing areas.

  10. A role for the androgen metabolite, 5alpha-androstane-3beta,17beta-diol, in modulating oestrogen receptor beta-mediated regulation of hormonal stress reactivity.

    PubMed

    Handa, R J; Weiser, M J; Zuloaga, D G

    2009-03-01

    Activation of the hypothalamic-pituitary-adrenal (HPA) axis is a basic response of animals to environmental perturbations that threaten homeostasis. These responses are regulated by neurones in the paraventricular nucleus of the hypothalamus (PVN) that synthesise and secrete corticotrophin-releasing hormone (CRH). Other PVN neuropeptides, such as arginine vasopressin and oxytocin, can also modulate activity of CRH neurones in the PVN and enhance CRH secretagogue activity of the anterior pituitary gland. In rodents, sex differences in HPA reactivity are well established; females exhibit a more robust activation of the HPA axis after stress than do males. These sex differences primarily result from opposing actions of sex steroids, testosterone and oestrogen, on HPA function. Ostreogen enhances stress activated adrenocorticotrophic hormone (ACTH) and corticosterone (CORT) secretion, whereas testosterone decreases the gain of the HPA axis and inhibits ACTH and CORT responses to stress. Data show that androgens can act directly on PVN neurones in the male rat through a novel pathway involving oestrogen receptor (ER)beta, whereas oestrogen acts predominantly through ERalpha. Thus, we examined the hypothesis that, in males, testosterone suppresses HPA function via an androgen metabolite that binds ERbeta. Clues to the neurobiological mechanisms underlying such a novel action can be gleaned from studies showing extensive colocalisation of ERbeta in oxytocin-containing cells of the PVN. Hence, in this review, we address the possibility that testosterone inhibits HPA reactivity by metabolising to 5alpha-androstane-3beta,17beta-diol, a compound that binds ERbeta and regulates oxytocin containing neurones of the PVN. These findings suggest a re-evaluation of studies examining pathways for androgen receptor signalling.

  11. Reactive Neurogenesis and Down-Regulation of the Potassium-Chloride Cotransporter KCC2 in the Cochlear Nuclei after Cochlear Deafferentation

    PubMed Central

    Tighilet, Brahim; Dutheil, Sophie; Siponen, Marina I.; Noreña, Arnaud J.

    2016-01-01

    While many studies have been devoted to investigating the homeostatic plasticity triggered by cochlear hearing loss, the cellular and molecular mechanisms involved in these central changes remain elusive. In the present study, we investigated the possibility of reactive neurogenesis after unilateral cochlear nerve section in the cochlear nucleus (CN) of cats. We found a strong cell proliferation in all the CN sub-divisions ipsilateral to the lesion. Most of the newly generated cells survive up to 1 month after cochlear deafferentation in all cochlear nuclei (except the dorsal CN) and give rise to a variety of cell types, i.e., microglial cells, astrocytes, and neurons. Interestingly, many of the newborn neurons had an inhibitory (GABAergic) phenotype. This result is intriguing since sensory deafferentation is usually accompanied by enhanced excitation, consistent with a reduction in central inhibition. The membrane potential effect of GABA depends, however, on the intra-cellular chloride concentration, which is maintained at low levels in adults by the potassium chloride co-transporter KCC2. The KCC2 density on the plasma membrane of neurons was then assessed after cochlear deafferentation in the cochlear nuclei ipsilateral and contralateral to the lesion. Cochlear deafferentation is accompanied by a strong down-regulation of KCC2 ipsilateral to the lesion at 3 and 30 days post-lesion. This study suggests that reactive neurogenesis and down-regulation of KCC2 is part of the vast repertoire involved in homeostatic plasticity triggered by hearing loss. These central changes may also play a role in the generation of tinnitus and hyperacusis. PMID:27630564

  12. Regulation of cellular marker modulated upon irradiation of low power laser light in burn injured mice

    NASA Astrophysics Data System (ADS)

    Rathnakar, Bharath; Prabhu, Vijendra; Rao, Bola Sadashiva Satish; Chandra, Subhash; Rai, Sharada; Mahato, Krishna Kishore

    2016-12-01

    The present study intends to understand the importance of cellular marker in tissue regeneration regulated upon irradiation of low power laser light in burn inflicted mice. Under anesthetic conditions, the thermal injury was induced on Swiss albino mice of either sex. Following injury, the animals were randomly divided into three groups; i. e., un-illuminated control, the group treated with 5% Povidone iodine (reference standard) and single exposure of 3 J/cm2 (830 nm). Burn tissue samples from each group were excised at day 6 post burn injury upon euthanization and used for histological and immunohistochemical analysis. Haematoxylin and Eosin (H and E) staining was performed on the selected sections to asses proliferation and angiogenesis at day 6 post-injury. For immunohistochemical analysis, tissue sections from all the three treatment groups on day 6 were stained using specific antibody against Proliferating cell nuclear antigen (PCNA). The results of the histological and immunohistochemical analysis showed improved tissue restoration in animals treated with optimal laser influence as compared to un-illuminated controls. The findings of present study clearly demonstrated the beneficial effects of 830 nm laser in burn wound healing and its influence in regulating the cellular marker.

  13. Small-Scale Hydroelectric Power Demonstration Project: reactivation of the Elk Rapids Hydroelectric Facility. Final technical and construction cost report

    SciTech Connect

    Not Available

    1985-05-01

    The Elk Rapids powerhouse dam is located on the Elk River channel in the Village of Elk Rapids, Michigan. Together with a small spillway structure located approximately 500 ft south of the dam, it constitutes the outlet to Lake Michigan for Elk Lake, Skegemog Lake, Torch Lake, Lake Bellaire, Clam Lake, and several smaller lakes. Power has been generated at the Elk Rapids site since the late nineteenth century, but the history of the present facility goes back to 1916 with the construction of the existing powerhouse dam by the Elk Rapids Iron Works Company. The facility was designed to contain four vertical-shaft generating units; however, only a single 270 hp Leffel type K unit was installed in 1916. In 1929, two additional Leffel units, rated 525 hp, were installed, and in 1930 a third 525 hp Leffel unit was added completely utilizing the capacity of the powerhouse and bringing the combined turbine capacity to 1845 hp.

  14. Power conditioning unit for photovoltaic power systems

    NASA Astrophysics Data System (ADS)

    Beghin, G.; Nguyen Phuoc, V. T.

    Operational features and components of a power conditioning unit for interconnecting solar cell module powers with a utility grid are outlined. The two-stage unit first modifies the voltage to desired levels on an internal dc link, then inverts the current in 2 power transformers connected to a vector summation control to neutralize harmonic distortion up to the 11th harmonic. The system operates in parallel with the grid with extra inductors to absorb line-to-line voltage and phase differences, and permits peak power use from the PV array. Reactive power is gained internally, and a power system controller monitors voltages, frequencies, and currents. A booster preregulator adjusts the input voltage from the array to provide voltage regulation for the inverter, and can commutate 450 amps. A total harmonic distortion of less than 5 percent is claimed, with a rating of 5 kVA, 50/60 Hz, 3-phase, and 4-wire.

  15. Control voltage and power fluctuations when connecting wind farms

    NASA Astrophysics Data System (ADS)

    Berinde, Ioan; Bǎlan, Horia; Oros Pop, Teodora Susana

    2015-12-01

    Voltage, frequency, active power and reactive power are very important parameters in terms of power quality. These parameters are followed when connecting any power plant, the more the connection of wind farms. Connecting wind farms to the electricity system must not cause interference outside the limits set by regulations. Modern solutions for fast and automatic voltage control and power fluctuations using electronic control systems of reactive power flows. FACTS (Flexible Alternating Current Transmision System) systems, established on the basis of power electronic circuits ensure control of electrical status quantities to achieve the necessary transfer of power to the power grid. FACTS devices can quickly control parameters and sizes of state power lines, such as impedance line voltages and phase angles of the voltages of the two ends of the line. Their use can lead to improvement in power system operation by increasing the transmission capacity of power lines, power flow control lines, improved static and transient stability reserve.

  16. Control voltage and power fluctuations when connecting wind farms

    SciTech Connect

    Berinde, Ioan Bălan, Horia Oros, Teodora Susana

    2015-12-23

    Voltage, frequency, active power and reactive power are very important parameters in terms of power quality. These parameters are followed when connecting any power plant, the more the connection of wind farms. Connecting wind farms to the electricity system must not cause interference outside the limits set by regulations. Modern solutions for fast and automatic voltage control and power fluctuations using electronic control systems of reactive power flows. FACTS (Flexible Alternating Current Transmision System) systems, established on the basis of power electronic circuits ensure control of electrical status quantities to achieve the necessary transfer of power to the power grid. FACTS devices can quickly control parameters and sizes of state power lines, such as impedance line voltages and phase angles of the voltages of the two ends of the line. Their use can lead to improvement in power system operation by increasing the transmission capacity of power lines, power flow control lines, improved static and transient stability reserve.

  17. Reactive oxygen species regulate programmed cell death progress of endosperm in winter wheat (Triticum aestivum L.) under waterlogging.

    PubMed

    Cheng, Xiang-Xu; Yu, Min; Zhang, Nan; Zhou, Zhu-Qing; Xu, Qiu-Tao; Mei, Fang-Zhu; Qu, Liang-Huan

    2016-03-01

    Previous studies have proved that waterlogging stress accelerates the programmed cell death (PCD) progress of wheat endosperm cells. A highly waterlogging-tolerant wheat cultivar Hua 8 and a waterlogging susceptible wheat cultivar Hua 9 were treated with different waterlogging durations, and then, dynamic changes of reactive oxygen species (ROS), gene expressions, and activities of antioxidant enzymes in endosperm cells were detected. The accumulation of ROS increased considerably after 7 days of waterlogging treatment (7 DWT) and 12 DWT in both cultivars compared with control group (under non-waterlogged conditions), culminated at 12 DAF (days after flowering) and reduced hereafter. Waterlogging resulted in a great increase of H2O2 and O2 (-) in plasma membranes, cell walls, mitochondrias, and intercellular spaces with ultracytochemical localization. Moreover, the deformation and rupture of cytomembranes as well as the swelling and distortion of mitochondria were obvious. Under waterlogging treatment conditions, catalase (CAT) gene expression increased in endosperm of Hua 8 but activity decreased. In addition, Mn superoxide dismutase (MnSOD) gene expression and superoxide dismutase (SOD) activity increased. Compared with Hua 8, both CAT, MnSOD gene expressions and CAT, SOD activities decreased in Hua 9. Moreover, ascorbic acid and mannitol relieve the intensifying of PCD processes in Hua 8 endosperm cells induced by waterlogging. These results indicate that ROS have important roles in the PCD of endosperm cells, the changes both CAT, MnSOD gene expressions and CAT, SOD activities directly affected the accumulation of ROS in two different wheat cultivars under waterlogging, ultimately led to the PCD acceleration of endosperm.

  18. Extracellular Redox Regulation of Intracellular Reactive Oxygen Generation, Mitochondrial Function and Lipid Turnover in Cultured Human Adipocytes

    PubMed Central

    Oliveira, Marcus F.; Burritt, Nathan; Corkey, Barbara E.

    2016-01-01

    Background Many tissues play an important role in metabolic homeostasis and the development of diabetes and obesity. We hypothesized that the circulating redox metabolome is a master metabolic regulatory system that impacts all organs and modulates reactive oxygen species (ROS) production, lipid peroxidation, energy production and changes in lipid turnover in many cells including adipocytes. Methods Differentiated human preadipocytes were exposed to the redox couples, lactate (L) and pyruvate (P), β–hydroxybutyrate (βOHB) and acetoacetate (Acoc), and the thiol-disulfides cysteine/ cystine (Cys/CySS) and GSH/GSSG for 1.5–4 hours. ROS measurements were done with CM-H2DCFDA. Lipid peroxidation (LPO) was assessed by a modification of the thiobarbituric acid method. Lipolysis was measured as glycerol release. Lipid synthesis was measured as 14C-glucose incorporated into lipid. Respiration was assessed using the SeaHorse XF24 analyzer and the proton leak was determined from the difference in respiration with oligomycin and antimycin A. Results Metabolites with increasing oxidation potentials (GSSG, CySS, Acoc) increased adipocyte ROS. In contrast, P caused a decrease in ROS compared with L. Acoc also induced a significant increase in both LPO and lipid synthesis. L and Acoc increased lipolysis. βOHB increased respiration, mainly due to an increased proton leak. GSSG, when present throughout 14 days of differentiation significantly increased fat accumulation, but not when added later. Conclusions We demonstrated that in human adipocytes changes in the external redox state impacted ROS production, LPO, energy efficiency, lipid handling, and differentiation. A more oxidized state generally led to increased ROS, LPO and lipid turnover and more reduction led to increased respiration and a proton leak. However, not all of the redox couples were the same suggesting compartmentalization. These data are consistent with the concept of the circulating redox metabolome as a

  19. Avicin D: A Protein Reactive Plant Isoprenoid Dephosphorylates Stat 3 by Regulating Both Kinase and Phosphatase Activities

    PubMed Central

    Haridas, Valsala; Nishimura, Goshi; Xu, Zhi-Xiang; Connolly, Fiona; Hanausek, Margaret; Walaszek, Zbigniew; Zoltaszek, Robert; Gutterman, Jordan U.

    2009-01-01

    Avicins, a class of electrophilic triterpenoids with pro-apoptotic, anti-inflammatory and antioxidant properties, have been shown to induce redox-dependant post-translational modification of cysteine residues to regulate protein function. Based on (a) the cross-talk that occurs between redox and phosphorylation processes, and (b) the role of Stat3 in the process of apoptosis and carcinogenesis, we chose to study the effects of avicins on the processes of phosphorylation/dephosphorylation in Stat3. Avicins dephosphorylate Stat3 in a variety of human tumor cell lines, leading to a decrease in the transcriptional activity of Stat3. The expression of Stat3-regulated proteins such as c-myc, cyclin D1, Bcl2, survivin and VEGF were reduced in response to avicin treatment. Underlying avicin-induced dephosphorylation of Stat3 was dephosphorylation of JAKs, as well as activation of protein phosphatase-1. Downregulation of both Stat3 activity and expression of Stat 3-controlled pro-survival proteins, contributes to the induction of apoptosis in avicin treated tumor cells. Based on the role of Stat3 in inflammation and wounding, and the in vivo inhibition of VEGF by avicins in a mouse skin carcinogenesis model, it is likely that avicin-induced inhibition of Stat3 activity results in the suppression of the pro-inflammatory and pro-oxidant stromal environment of tumors. Activation of PP-1, which also acts as a cellular economizer, combined with the redox regulation by avicins, can aid in redirecting metabolism from growth promoting anabolic to energy sparing pathways. PMID:19440292

  20. Up-regulation of CB2 receptors in reactive astrocytes in canine degenerative myelopathy, a disease model of amyotrophic lateral sclerosis.

    PubMed

    Fernández-Trapero, María; Espejo-Porras, Francisco; Rodríguez-Cueto, Carmen; Coates, Joan R; Pérez-Díaz, Carmen; de Lago, Eva; Fernández-Ruiz, Javier

    2017-01-09

    Targeting the CB2 receptor afforded neuroprotection in SOD1(G93A) mutant mice, a model of amyotrophic lateral sclerosis (ALS). The neuroprotective effects of CB2 receptors were facilitated by their up-regulation in the spinal cord in SOD1(G93A) mutant mice. Herein, we have investigated whether a similar CB2 receptor up-regulation, as well as parallel changes in other endocannabinoid elements, are evident in the spinal cord of dogs with degenerative myelopathy (DM), caused from mutations in the superoxide dismutase 1 gene (SOD1). We used well-characterized post-mortem spinal cords from unaffected and DM-affected dogs. Tissues were used first to confirm the loss of motor neurons using Nissl staining, which was accompanied by glial reactivity (elevated GFAP and Iba-1 immunoreactivity). Next, we investigated possible differences in the expression of endocannabinoid genes measured by qPCR between DM-affected and control dogs. We found no changes in the CB1 receptor (also found with CB1 receptor immunostaining) as well as in NAPE-PLD, DAGL, FAAH and MAGL enzymes. In contrast, CB2 receptor levels were significantly elevated in DM-affected dogs determined by qPCR and Western-blotting, results reconfirmed in the grey matter using CB2 receptor immunostaining. Using double-labelling immunofluorescence, CB2 receptor immunolabelling co-localized with GFAP but not Iba-1, indicating up-regulation of CB2 receptors on astrocytes in DM-affected dogs. In summary, our results demonstrated a marked up-regulation of CB2 receptors occurring in the spinal cord in canine DM, which was concentrated in activated astrocytes. Such receptors may be used as a potential target to enhance the neuroprotective effects exerted by these glial cells.

  1. Bcl-2 family proteins as regulators of cancer cell invasion and metastasis: a review focusing on mitochondrial respiration and reactive oxygen species.

    PubMed

    Um, Hong-Duck

    2016-02-02

    Although Bcl-2 family proteins were originally identified as key regulators of apoptosis, an impressive body of evidence has shown that pro-survival members of the Bcl-2 family, including Bcl-2, Bcl-XL, and Bcl-w, can also promote cell migration, invasion, and cancer metastasis. Interestingly, cell invasion was recently found to be suppressed by multidomain pro-apoptotic members of the Bcl-2 family, such as Bax and Bak. While the mechanisms underlying these new functions of Bcl-2 proteins are just beginning to be studied, reactive oxygen species (ROS) have emerged as inducers of cell invasion and the production of ROS from mitochondrial respiration is known to be promoted and suppressed by the pro-survival and multidomain pro-apoptotic Bcl-2 family members, respectively. Here, I review the evidence supporting the ability of Bcl-2 proteins to regulate cancer cell invasion and metastasis, and discuss our current understanding of their underlying mechanisms, with a particular focus on mitochondrial respiration and ROS, which could have implications for the development of strategies to overcome tumor progression.

  2. GDF15 contributes to radioresistance and cancer stemness of head and neck cancer by regulating cellular reactive oxygen species via a SMAD-associated signaling pathway

    PubMed Central

    Lee, Li-Yu; Fan, Kang-Hsing; Lu, Ya-Ching; Li, Yi-Chen; Chiang, Chang-Hsu; You, Guo-Rung; Chen, Hsin-Ying; Cheng, Ann-Joy

    2017-01-01

    Radiotherapy is an integral part for the treatment of head and neck cancer (HNC), while radioresistance is a major cause leads to treatment failure. GDF15, a member of the TGF-β superfamily, is hypothesized to participate in various types of homeostasis. However, the potential role of this molecule in regulation of radiosensitivity remains unclear. In this study, we demonstrated that GDF15 contributed to radioresistance of HNC, as determined by both gain- and lost-of-functional experiments. These results were achieved by the induction of mitochondrial membrane potential and suppression of intracellular reactive oxygen species (ROS). We further showed that GDF15 facilitated the conversion of cancer stemness, as assessed by the promotion of CD44+ and ALDH1+ cell populations and spheroid cell formation. At molecular level, GDF15 conferred to these cellular functions was through phosphorylated SMAD1 proteins to elite downstream signaling molecules. These cellular results were further confirmed in a tumor xenograft mouse study. Taken together, our results demonstrated that GDF15 contributed to radioresistance and cancer stemness by regulating cellular ROS levels via a SMAD-associated signaling pathway. GDF15 may serve as a prediction marker of radioresistance and a therapeutic target for the development of radio-sensitizing agents for the treatment of refractory HNC. PMID:27903972

  3. Integrin alpha1beta1 controls reactive oxygen species synthesis by negatively regulating epidermal growth factor receptor-mediated Rac activation.

    PubMed

    Chen, Xiwu; Abair, Tristin D; Ibanez, Maria R; Su, Yan; Frey, Mark R; Dise, Rebecca S; Polk, D Brent; Singh, Amar B; Harris, Raymond C; Zent, Roy; Pozzi, Ambra

    2007-05-01

    Integrins control many cell functions, including generation of reactive oxygen species (ROS) and regulation of collagen synthesis. Mesangial cells, found in the glomerulus of the kidney, are able to produce large amounts of ROS via the NADPH oxidase. We previously demonstrated that integrin alpha1-null mice develop worse fibrosis than wild-type mice following glomerular injury and this is due, in part, to excessive ROS production by alpha1-null mesangial cells. In the present studies, we describe the mechanism whereby integrin alpha1-null mesangial cells produce excessive ROS. Integrin alpha1-null mesangial cells have constitutively increased basal levels of activated Rac1, which result in its increased translocation to the cell membrane, excessive ROS production, and consequent collagen IV deposition. Basal Rac1 activation is a direct consequence of ligand-independent increased epidermal growth factor receptor (EGFR) phosphorylation in alpha1-null mesangial cells. Thus, our study demonstrates that integrin alpha1beta1-EGFR cross talk is a key step in negatively regulating Rac1 activation, ROS production, and excessive collagen synthesis, which is a hallmark of diseases characterized by irreversible fibrosis.

  4. GDF15 contributes to radioresistance and cancer stemness of head and neck cancer by regulating cellular reactive oxygen species via a SMAD-associated signaling pathway.

    PubMed

    Li, Yan-Liang; Chang, Joseph T; Lee, Li-Yu; Fan, Kang-Hsing; Lu, Ya-Ching; Li, Yi-Chen; Chiang, Chang-Hsu; You, Guo-Rung; Chen, Hsin-Ying; Cheng, Ann-Joy

    2017-01-03

    Radiotherapy is an integral part for the treatment of head and neck cancer (HNC), while radioresistance is a major cause leads to treatment failure. GDF15, a member of the TGF-β superfamily, is hypothesized to participate in various types of homeostasis. However, the potential role of this molecule in regulation of radiosensitivity remains unclear. In this study, we demonstrated that GDF15 contributed to radioresistance of HNC, as determined by both gain- and lost-of-functional experiments. These results were achieved by the induction of mitochondrial membrane potential and suppression of intracellular reactive oxygen species (ROS). We further showed that GDF15 facilitated the conversion of cancer stemness, as assessed by the promotion of CD44+ and ALDH1+ cell populations and spheroid cell formation. At molecular level, GDF15 conferred to these cellular functions was through phosphorylated SMAD1 proteins to elite downstream signaling molecules. These cellular results were further confirmed in a tumor xenograft mouse study. Taken together, our results demonstrated that GDF15 contributed to radioresistance and cancer stemness by regulating cellular ROS levels via a SMAD-associated signaling pathway. GDF15 may serve as a prediction marker of radioresistance and a therapeutic target for the development of radio-sensitizing agents for the treatment of refractory HNC.

  5. KV7 channels contribute to paracrine, but not metabolic or ischemic, regulation of coronary vascular reactivity in swine.

    PubMed

    Goodwill, Adam G; Fu, Lijuan; Noblet, Jillian N; Casalini, Eli D; Sassoon, Daniel; Berwick, Zachary C; Kassab, Ghassan S; Tune, Johnathan D; Dick, Gregory M

    2016-03-15

    Hydrogen peroxide (H2O2) and voltage-dependent K(+) (KV) channels play key roles in regulating coronary blood flow in response to metabolic, ischemic, and paracrine stimuli. The KV channels responsible have not been identified, but KV7 channels are possible candidates. Existing data regarding KV7 channel function in the coronary circulation (limited to ex vivo assessments) are mixed. Thus we examined the hypothesis that KV7 channels are present in cells of the coronary vascular wall and regulate vasodilation in swine. We performed a variety of molecular, biochemical, and functional (in vivo and ex vivo) studies. Coronary arteries expressed KCNQ genes (quantitative PCR) and KV7.4 protein (Western blot). Immunostaining demonstrated KV7.4 expression in conduit and resistance vessels, perhaps most prominently in the endothelial and adventitial layers. Flupirtine, a KV7 opener, relaxed coronary artery rings, and this was attenuated by linopirdine, a KV7 blocker. Endothelial denudation inhibited the flupirtine-induced and linopirdine-sensitive relaxation of coronary artery rings. Moreover, linopirdine diminished bradykinin-induced endothelial-dependent relaxation of coronary artery rings. There was no effect of intracoronary flupirtine or linopirdine on coronary blood flow at the resting heart rate in vivo. Linopirdine had no effect on coronary vasodilation in vivo elicited by ischemia, H2O2, or tachycardia. However, bradykinin increased coronary blood flow in vivo, and this was attenuated by linopirdine. These data indicate that KV7 channels are expressed in some coronary cell type(s) and influence endothelial function. Other physiological functions of coronary vascular KV7 channels remain unclear, but they do appear to contribute to endothelium-dependent responses to paracrine stimuli.

  6. KV7 channels contribute to paracrine, but not metabolic or ischemic, regulation of coronary vascular reactivity in swine

    PubMed Central

    Goodwill, Adam G.; Fu, Lijuan; Noblet, Jillian N.; Casalini, Eli D.; Berwick, Zachary C.; Kassab, Ghassan S.; Tune, Johnathan D.

    2016-01-01

    Hydrogen peroxide (H2O2) and voltage-dependent K+ (KV) channels play key roles in regulating coronary blood flow in response to metabolic, ischemic, and paracrine stimuli. The KV channels responsible have not been identified, but KV7 channels are possible candidates. Existing data regarding KV7 channel function in the coronary circulation (limited to ex vivo assessments) are mixed. Thus we examined the hypothesis that KV7 channels are present in cells of the coronary vascular wall and regulate vasodilation in swine. We performed a variety of molecular, biochemical, and functional (in vivo and ex vivo) studies. Coronary arteries expressed KCNQ genes (quantitative PCR) and KV7.4 protein (Western blot). Immunostaining demonstrated KV7.4 expression in conduit and resistance vessels, perhaps most prominently in the endothelial and adventitial layers. Flupirtine, a KV7 opener, relaxed coronary artery rings, and this was attenuated by linopirdine, a KV7 blocker. Endothelial denudation inhibited the flupirtine-induced and linopirdine-sensitive relaxation of coronary artery rings. Moreover, linopirdine diminished bradykinin-induced endothelial-dependent relaxation of coronary artery rings. There was no effect of intracoronary flupirtine or linopirdine on coronary blood flow at the resting heart rate in vivo. Linopirdine had no effect on coronary vasodilation in vivo elicited by ischemia, H2O2, or tachycardia. However, bradykinin increased coronary blood flow in vivo, and this was attenuated by linopirdine. These data indicate that KV7 channels are expressed in some coronary cell type(s) and influence endothelial function. Other physiological functions of coronary vascular KV7 channels remain unclear, but they do appear to contribute to endothelium-dependent responses to paracrine stimuli. PMID:26825518

  7. Effect on the condition of the metal in A K-300-3.5 turbine owing to multicycle fatigue from participation of a power generating unit in grid frequency and power regulation

    SciTech Connect

    Lebedeva, A. I.; Zorchenko, N. V.; Prudnikov, A. A.

    2011-09-15

    The effect on the condition of the rotor material owing to multicycle fatigue caused by variable stresses during participation of a power generating unit in grid frequency and power regulation is evaluated using the K-300-23.5 steam turbine as an example. It is shown that during normalized primary frequency regulation the safety factor is at least 50, while during automatic secondary regulation of frequency and power there is essentially no damage to the metal.

  8. Regulation and deregulation of cholesterol homeostasis: The liver as a metabolic “power station”

    PubMed Central

    Trapani, Laura; Segatto, Marco; Pallottini, Valentina

    2012-01-01

    Cholesterol plays several structural and metabolic roles that are vital for human biology. It spreads along the entire plasma membrane of the cell, modulating fluidity and concentrating in specialized sphingolipid-rich domains called rafts and caveolae. Cholesterol is also a substrate for steroid hormones. However, too much cholesterol can lead to pathological pictures such as atherosclerosis, which is a consequence of the accumulation of cholesterol into the cells of the artery wall. The liver is considered to be the metabolic power station of mammalians, where cholesterol homeostasis relies on an intricate network of cellular processes whose deregulations can lead to several life-threatening pathologies, such as familial and age-related hypercholesterolemia. Cholesterol homeostasis maintenance is carried out by: biosynthesis, via 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) activity; uptake, through low density lipoprotein receptors (LDLr); lipoprotein release in the blood; storage by esterification; and degradation and conversion into bile acids. Both HMGR and LDLr are transcribed as a function of cellular sterol amount by a family of transcription factors called sterol regulatory element binding proteins that are responsible for the maintenance of cholesterol homeostasis through an intricate mechanism of regulation. Cholesterol obtained by hepatic de novo synthesis can be esterified and incorporated into apolipoprotein B-100-containing very low density lipoproteins, which are then secreted into the bloodstream for transport to peripheral tissues. Moreover, dietary cholesterol is transferred from the intestine to the liver by high density lipoproteins (HDLs); all HDL particles are internalized in the liver, interacting with the hepatic scavenger receptor (SR-B1). Here we provide an updated overview of liver cholesterol metabolism regulation and deregulation and the causes of cholesterol metabolism-related diseases. Moreover, current pharmacological

  9. Regulation and deregulation of cholesterol homeostasis: The liver as a metabolic "power station".

    PubMed

    Trapani, Laura; Segatto, Marco; Pallottini, Valentina

    2012-06-27

    Cholesterol plays several structural and metabolic roles that are vital for human biology. It spreads along the entire plasma membrane of the cell, modulating fluidity and concentrating in specialized sphingolipid-rich domains called rafts and caveolae. Cholesterol is also a substrate for steroid hormones. However, too much cholesterol can lead to pathological pictures such as atherosclerosis, which is a consequence of the accumulation of cholesterol into the cells of the artery wall. The liver is considered to be the metabolic power station of mammalians, where cholesterol homeostasis relies on an intricate network of cellular processes whose deregulations can lead to several life-threatening pathologies, such as familial and age-related hypercholesterolemia. Cholesterol homeostasis maintenance is carried out by: biosynthesis, via 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) activity; uptake, through low density lipoprotein receptors (LDLr); lipoprotein release in the blood; storage by esterification; and degradation and conversion into bile acids. Both HMGR and LDLr are transcribed as a function of cellular sterol amount by a family of transcription factors called sterol regulatory element binding proteins that are responsible for the maintenance of cholesterol homeostasis through an intricate mechanism of regulation. Cholesterol obtained by hepatic de novo synthesis can be esterified and incorporated into apolipoprotein B-100-containing very low density lipoproteins, which are then secreted into the bloodstream for transport to peripheral tissues. Moreover, dietary cholesterol is transferred from the intestine to the liver by high density lipoproteins (HDLs); all HDL particles are internalized in the liver, interacting with the hepatic scavenger receptor (SR-B1). Here we provide an updated overview of liver cholesterol metabolism regulation and deregulation and the causes of cholesterol metabolism-related diseases. Moreover, current pharmacological

  10. Central role of endogenous Toll-like receptor-2 activation in regulating inflammation, reactive oxygen species production, and subsequent neointimal formation after vascular injury

    SciTech Connect

    Shishido, Tetsuro . E-mail: Tetsuro_Shishido@URMC.Rochester.edu; Nozaki, Naoki; Takahashi, Hiroki; Arimoto, Takanori; Niizeki, Takeshi; Koyama, Yo; Abe, Jun-ichi; Takeishi, Yasuchika; Kubota, Isao

    2006-07-14

    Background: It is now evident that inflammation after vascular injury has significant impact on the restenosis after revascularization procedures such as angioplasty, stenting, and bypass grafting. However, the mechanisms that regulate inflammation and repair after vascular injury are incompletely understood. Here, we report that vascular injury-mediated cytokine expression, reactive oxygen species (ROS) production, as well as subsequent neointimal formation requires Toll-like receptor-2 (TLR-2) mediated signaling pathway in vivo. Methods and results: Vascular injury was induced by cuff-placement around the femoral artery in non-transgenic littermates (NLC) and TLR-2 knockout (TLR-2KO) mice. After cuff-placement in NLC mice, expression of TLR-2 was significantly increased in both smooth muscle medial layer and adventitia. Interestingly, we found that inflammatory genes expression such as tumor necrosis factor-{alpha}, interleukin-1{beta} (IL-1{beta}), IL-6, and monocyte chemoattractant protein-1 were markedly decreased in TLR-2KO mice compared with NLC mice. In addition, ROS production after vascular injury was attenuated in TLR-2KO mice compared with NLC mice. Since we observed the significant role of endogenous TLR-2 activation in regulating inflammatory responses and ROS production after vascular injury, we determined whether inhibition of endogenous TLR-2 activation can inhibit neointimal proliferation after vascular injury. Neointimal hyperplasia was markedly suppressed in TLR-2KO mice compared with WT mice at both 2 and 4 weeks after vascular injury. Conclusions: These findings suggested that endogenous TLR-2 activation might play a central role in the regulation of vascular inflammation as well as subsequent neointimal formation in injured vessels.

  11. Spatial and temporal regulation of the metabolism of reactive oxygen and nitrogen species during the early development of pepper (Capsicum annuum) seedlings

    PubMed Central

    Airaki, Morad; Leterrier, Marina; Valderrama, Raquel; Chaki, Mounira; Begara-Morales, Juan C.; Barroso, Juan B.; del Río, Luis A.; Palma, José M.; Corpas, Francisco J.

    2015-01-01

    Background and Aims The development of seedlings involves many morphological, physiological and biochemical processes, which are controlled by many factors. Some reactive oxygen and nitrogen species (ROS and RNS, respectively) are implicated as signal molecules in physiological and phytopathological processes. Pepper (Capsicum annuum) is a very important crop and the goal of this work was to provide a framework of the behaviour of the key elements in the metabolism of ROS and RNS in the main organs of pepper during its development. Methods The main seedling organs (roots, hypocotyls and green cotyledons) of pepper seedlings were analysed 7, 10 and 14 d after germination. Activity and gene expression of the main enzymatic antioxidants (catalase, ascorbate–glutathione cycle enzymes), NADP-generating dehydrogenases and S-nitrosoglutathione reductase were determined. Cellular distribution of nitric oxide (·NO), superoxide radical (O2·–) and peroxynitrite (ONOO–) was investigated using confocal laser scanning microscopy. Key Results The metabolism of ROS and RNS during pepper seedling development was highly regulated and showed significant plasticity, which was co-ordinated among the main seedling organs, resulting in correct development. Catalase showed higher activity in the aerial parts of the seedling (hypocotyls and green cotyledons) whereas roots of 7-d-old seedlings contained higher activity of the enzymatic components of the ascorbate glutathione cycle, NADP-isocitrate dehydrogenase and NADP-malic enzyme. Conclusions There is differential regulation of the metabolism of ROS, nitric oxide and NADP dehydrogenases in the different plant organs during seedling development in pepper in the absence of stress. The metabolism of ROS and RNS seems to contribute significantly to plant development since their components are involved directly or indirectly in many metabolic pathways. Thus, specific molecules such as H2O2 and NO have implications for signalling

  12. c-Jun NH(2)-terminal kinase signaling axis regulates diallyl trisulfide-induced generation of reactive oxygen species and cell cycle arrest in human prostate cancer cells.

    PubMed

    Antosiewicz, Jedrzej; Herman-Antosiewicz, Anna; Marynowski, Stanley W; Singh, Shivendra V

    2006-05-15

    We have shown previously that generation of reactive oxygen species (ROS) is a critical event in G(2)-M phase cell cycle arrest caused by diallyl trisulfide (DATS), which is a highly promising anticancer constituent of processed garlic. Using DU145 and PC-3 human prostate cancer cells as a model, we now report a novel mechanism involving c-Jun NH(2)-terminal kinase (JNK) signaling axis, which is known for its role in regulation of cell survival and apoptosis, in DATS-induced ROS production. The DATS-induced ROS generation, G(2)-M phase cell cycle arrest and degradation, and hyperphosphorylation of Cdc25C were significantly attenuated in the presence of EUK134, a combined mimetic of superoxide dismutase and catalase. Interestingly, the DATS-induced ROS generation and G(2)-M phase cell cycle arrest were also inhibited significantly in the presence of desferrioxamine, an iron chelator, but this protection was not observed with iron-saturated desferrioxamine. DATS treatment caused a marked increase in the level of labile iron that was accompanied by degradation of light chain of iron storage protein ferritin. Interestingly, DATS-mediated degradation of ferritin, increase in labile iron pool, ROS generation, and/or cell cycle arrest were significantly attenuated by ectopic expression of a catalytically inactive mutant of JNK kinase 2 and RNA interference of stress-activated protein kinase/extracellular signal-regulated kinase 1 (SEK1), upstream kinases in JNK signal transduction pathway. In conclusion, the present study provides experimental evidence to indicate existence of a novel pathway involving JNK signaling axis in regulation of DATS-induced ROS generation.

  13. Role of reactive oxygen species in the signalling cascade of cyclosporine A-mediated up-regulation of eNOS in vascular endothelial cells

    PubMed Central

    López-Ongil, S; Hernández-Perera, O; Navarro-Antolín, J; Pérez de Lema, G; Rodríguez-Puyol, M; Lamas, S; Rodríguez-Puyol, D

    1998-01-01

    Cyclosporine A (CsA) increases eNOS mRNA expression in bovine cultured aortic endothelial cells (BAEC). As some effects of CsA may be mediated by reactive oxygen species (ROS), present experiments were devoted to test the hypothesis that the CsA-induced eNOS up-regulation could be dependent on an increased synthesis of ROS.CsA induced a dose-dependent increase of ROS synthesis, with the two fluorescent probes used, DHR123 (CsA 1 μM: 305±7% over control) and H2DCFDA (CsA 1 μM: 178±6% over control).Two ROS generating systems, xanthine plus xanthine oxidase (XXO) and glucose oxidase (GO), increased the expression of eNOS mRNA in BAEC, an effect which was maximal after 8 h of incubation (XXO: 168±21% of control values. GO: 208±18% of control values). The ROS-dependent increased eNOS mRNA expression was followed by an increase in eNOS activity.The effect of CsA on eNOS mRNA expression was abrogated by catalase, and superoxide dismutase (SOD). In contrast, the antioxidant PDTC augmented eNOS mRNA expression, both in basal conditions and in the presence of CsA.The potential participation of the transcription factor AP-1 was explored. Electrophoretic mobility shift assays were consistent with an increase in AP-1 DNA-binding activity in BAEC treated with CsA or glucose oxidase.The present results support a role for ROS, particularly superoxide anion and hydrogen peroxide, as mediators of the CsA-induced eNOS mRNA up-regulation. Furthermore, they situate ROS as potential regulators of gene expression in endothelial cells, both in physiological and pathophysiological situations. PMID:9647467

  14. Distinct p21 requirements for regulating normal and self-reactive T cells through IFN-γ production.

    PubMed

    Daszkiewicz, Lidia; Vázquez-Mateo, Cristina; Rackov, Gorjana; Ballesteros-Tato, André; Weber, Kathrin; Madrigal-Avilés, Adrián; Di Pilato, Mauro; Fotedar, Arun; Fotedar, Rati; Flores, Juana M; Esteban, Mariano; Martínez-A, Carlos; Balomenos, Dimitrios

    2015-01-09

    Self/non-self discrimination characterizes immunity and allows responses against pathogens but not self-antigens. Understanding the principles that govern this process is essential for designing autoimmunity treatments. p21 is thought to attenuate autoreactivity by limiting T cell expansion. Here, we provide direct evidence for a p21 role in controlling autoimmune T cell autoreactivity without affecting normal T cell responses. We studied C57BL/6, C57BL/6/lpr and MRL/lpr mice overexpressing p21 in T cells, and showed reduced autoreactivity and lymphadenopathy in C57BL/6/lpr, and reduced mortality in MRL/lpr mice. p21 inhibited effector/memory CD4(+) CD8(+) and CD4(-)CD8(-) lpr T cell accumulation without altering defective lpr apoptosis. This was mediated by a previously non-described p21 function in limiting T cell overactivation and overproduction of IFN-γ, a key lupus cytokine. p21 did not affect normal T cell responses, revealing differential p21 requirements for autoreactive and normal T cell activity regulation. The underlying concept of these findings suggests potential treatments for lupus and autoimmune lymphoproliferative syndrome, without compromising normal immunity.

  15. Melatonin Improved Anthocyanin Accumulation by Regulating Gene Expressions and Resulted in High Reactive Oxygen Species Scavenging Capacity in Cabbage

    PubMed Central

    Zhang, Na; Sun, Qianqian; Li, Hongfei; Li, Xingsheng; Cao, Yunyun; Zhang, Haijun; Li, Shuangtao; Zhang, Lei; Qi, Yan; Ren, Shuxin; Zhao, Bing; Guo, Yang-Dong

    2016-01-01

    In this work, we found, that exogenous melatonin pretreatment improved anthocyanin accumulation (1- to 2-fold) in cabbage. To verify the relationship with melatonin and anthocyanin, an Arabidopsis mutant, snat, which expresses a defective form of the melatonin biosynthesis enzyme SNAT (Serotonin N-acetyl transferase), was employed. Under cold conditions, the foliage of wild-type Arabidopsis exhibited a deeper red color than the snat mutant. This finding further proved, that exogenous melatonin treatment was able to affect anthocyanin accumulation. To gain a better understanding of how exogenous melatonin upregulates anthocyanin, we measured gene expression in cabbage samples treated with melatonin and untreated controls. We found that the transcript levels of anthocyanin biosynthetic genes were upregulated by melatonin treatment. Moreover, melatonin treatment increased the expression levels of the transcription factors MYB, bHLH, and WD40, which constitute the transcriptional activation complex responsible for coordinative regulation of anthocyanin biosynthetic genes. We found, that free radical generation was downregulated, whereas the osmotic adjustment and antioxidant capacities were upregulated in exogenous melatonin-treated cabbage plants. We concluded, that melatonin increases anthocyanin production and benefits cabbage growth. PMID:27047496

  16. Mercury emission trend influenced by stringent air pollutants regulation for coal-fired power plants in Korea

    NASA Astrophysics Data System (ADS)

    Pudasainee, Deepak; Kim, Jeong-Hun; Seo, Yong-Chil

    2009-12-01

    Regulatory control of mercury emission from anthropogenic sources has become a global concern in the recent past. Coal-fired power plants are one of the largest sources of anthropogenic mercury emission into the atmosphere. This paper summarizes the current reducing trend of mercury emission as co-beneficial effect by more stringent regulation changes to control primary air pollutants with introducing test results from the commercial coal-fired facilities and suggesting a guideline for future regulatory development in Korea. On average, mercury emission concentrations ranged 16.3-2.7 μg Sm -3, 2.4-1.1 μg Sm -3, 3.1-0.7 μg Sm -3 from anthracite coal-fired power plants equipped with electrostatic precipitator (ESP), bituminous coal-fired power plants with ESP + flue gas desulphurization (FGD) and bituminous coal-fired power plants with selective catalytic reactor (SCR) + cold side (CS) - ESP + wet FGD, respectively. Among the existing air pollution control devices, the best configuration for mercury removal in coal-fired power plants was SCR + CS - ESP + wet FGD, which were installed due to the stringent regulation changes to control primary air pollutants emission such as SO 2, NOx and dust. It was estimated that uncontrolled and controlled mercury emission from coal-fired power plants as 10.3 ton yr -1 and 3.2 ton yr -1 respectively. After the installation of ESP, FGD and SCR system, following the enforcement of the stringent regulation, 7.1 ton yr -1 of mercury emission has been reduced (nearly 69%) from coal-fired power plants as a co-benefit control. Based on the overall study, a sample guideline including emission limits were suggested which will be applied to develop a countermeasure for controlling mercury emission from coal-fired power plants.

  17. 76 FR 67259 - Frequency Regulation Compensation in the Organized Wholesale Power Markets

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-31

    ... electric markets and ensure that providers of frequency regulation receive just and reasonable and not... regulation in the organized wholesale electric markets and ensure that providers of frequency regulation... network pilot programs before requiring a revision of frequency regulation service.\\46\\ \\46\\ EEI May...

  18. Regulation of macromolecular modulators of urinary stone formation by reactive oxygen species: transcriptional study in an animal model of hyperoxaluria.

    PubMed

    Khan, Saeed R; Joshi, Sunil; Wang, Wei; Peck, Ammon B

    2014-06-01

    We used an unbiased approach of gene expression profiling to determine differential gene expression of all the macromolecular modulators (MMs) considered to be involved in stone formation, in hyperoxaluric rats, with and without treatment with the NADPH oxidase inhibitor apocynin. Male rats were fed rat chow or chow supplemented with 5% wt/wt hydroxy-l-proline (HLP) with or without apocynin-supplemented water. After 28 days, rats were euthanized and their kidneys explanted. Total RNA was isolated and microarray analysis was conducted using the Illumina bead array reader. Gene ontology analysis and the pathway analyses of the genes were done using Database for Annotation, Visualization of Integrated Discovery enrichment analysis tool. Quantitative RT-PCR of selected genes was carried out to verify the microarray results. Expression of selected gene products was confirmed using immunohistochemistry. Administration of HLP led to crystal deposition. Genes encoding for fibronectin, CD 44, fetuin B, osteopontin, and matrix-gla protein were upregulated while those encoding for heavy chains of inter-alpha-inhibitor 1, 3, and 4, calgranulin B, prothrombin, and Tamm-Horsfall protein were downregulated. HLP-fed rats receiving apocynin had a significant reversal in gene expression profiles: those that were upregulated came down while those that were downregulated stepped up. Apocynin treatment resulted in near complete absence of crystals. Clearly, there are two types of MMs; one is downregulated while the other is upregulated during hyperoxaluria and crystal deposition. Apparently gene and protein expressions of known macromolecular modulators of CaOx crystallization are likely regulated by ROS produced in part through the activation of NADPH oxidase.

  19. Sodium Nitrate Induces Reactive Oxygen Species That Lower the Antioxidant Power, Damage the Membrane, and Alter Pathways of Glucose Metabolism in Human Erythrocytes.

    PubMed

    Ansari, Fariheen Aisha; Mahmood, Riaz

    2015-12-09

    Nitrate salts are widely used as food additives and nitrogenous fertilizers and are present as contaminants in drinking water supplies. The effect of different concentrations (1-15 mM) of sodium nitrate (NaNO3) on human erythrocytes was studied under in vitro conditions. Treatment of erythrocytes with NaNO3 resulted in increases in methemoglobin levels, lipid peroxidation, and protein oxidation and a decrease in glutathione content. There were changes in the activities of all major antioxidant defense enzymes, and the pathways of glucose metabolism were also affected. Increased generation of reactive oxygen species (ROS) took place while the antioxidant power was impaired. The osmotic fragility of cells was increased, and membrane-bound enzymes were greatly inhibited. All changes were statistically significant at a probability level of P < 0.05 at all concentrations of NaNO3 except the lowest (1 mM). Thus, NaNO3 generates ROS that cause significant damage to human erythrocytes and interfere in normal cellular pathways.

  20. RelA-Mediated BECN1 Expression Is Required for Reactive Oxygen Species-Induced Autophagy in Oral Cancer Cells Exposed to Low-Power Laser Irradiation

    PubMed Central

    Wu, Chieh-Shan; Chen, Chien-Hsun; Wu, Sam; Chang, Hsueh-Wei; Kuo, Soong-Yu; Fu, Earl; Liu, Pei-Feng; Hsieh, Yao-Dung

    2016-01-01

    Low-power laser irradiation (LPLI) is a non-invasive and safe method for cancer treatment that alters a variety of physiological processes in the cells. Autophagy can play either a cytoprotective role or a detrimental role in cancer cells exposed to stress. The detailed mechanisms of autophagy and its role on cytotoxicity in oral cancer cells exposed to LPLI remain unclear. In this study, we showed that LPLI at 810 nm with energy density 60 J/cm2 increased the number of microtubule associated protein 1 light chain 3 (MAP1LC3) puncta and increased autophagic flux in oral cancer cells. Moreover, reactive oxygen species (ROS) production was induced, which increased RelA transcriptional activity and beclin 1 (BECN1) expression in oral cancer cells irradiated with LPLI. Furthermore, ROS scavenger or knockdown of RelA diminished LPLI-induced BECN1 expression and MAP1LC3-II conversion. In addition, pharmacological and genetic ablation of autophagy significantly enhanced the effects of LPLI-induced apoptosis in oral cancer cells. These results suggest that autophagy may be a resistant mechanism for LPLI-induced apoptosis in oral cancer cells. PMID:27632526

  1. RelA-Mediated BECN1 Expression Is Required for Reactive Oxygen Species-Induced Autophagy in Oral Cancer Cells Exposed to Low-Power Laser Irradiation.

    PubMed

    Shu, Chih-Wen; Chang, Hong-Tai; Wu, Chieh-Shan; Chen, Chien-Hsun; Wu, Sam; Chang, Hsueh-Wei; Kuo, Soong-Yu; Fu, Earl; Liu, Pei-Feng; Hsieh, Yao-Dung

    2016-01-01

    Low-power laser irradiation (LPLI) is a non-invasive and safe method for cancer treatment that alters a variety of physiological processes in the cells. Autophagy can play either a cytoprotective role or a detrimental role in cancer cells exposed to stress. The detailed mechanisms of autophagy and its role on cytotoxicity in oral cancer cells exposed to LPLI remain unclear. In this study, we showed that LPLI at 810 nm with energy density 60 J/cm2 increased the number of microtubule associated protein 1 light chain 3 (MAP1LC3) puncta and increased autophagic flux in oral cancer cells. Moreover, reactive oxygen species (ROS) production was induced, which increased RelA transcriptional activity and beclin 1 (BECN1) expression in oral cancer cells irradiated with LPLI. Furthermore, ROS scavenger or knockdown of RelA diminished LPLI-induced BECN1 expression and MAP1LC3-II conversion. In addition, pharmacological and genetic ablation of autophagy significantly enhanced the effects of LPLI-induced apoptosis in oral cancer cells. These results suggest that autophagy may be a resistant mechanism for LPLI-induced apoptosis in oral cancer cells.

  2. New Methodology for Evaluating Optimal Pricing for Primary Regulation of Deregulated Power Systems under Steady State Condition

    NASA Astrophysics Data System (ADS)

    Satyaramesh, P. V.; RadhaKrishna, C.

    2013-06-01

    A generalized pricing structure for procurement of power under frequency ancillary service is developed in this paper. It is a frequency linked-price model and suitable for deregulation market environment. This model takes into consideration: governor characteristics and frequency characteristics of generator as additional parameters in load flow method. The main objective of the new approach proposed in this paper is to establish bidding price structure for frequency regulation services in competitive ancillary electrical markets under steady state condition. Lot of literatures are available for calculating the frequency deviations with respect to load changes by using dynamic simulation methods. But in this paper, the model computes the frequency deviations for additional requirements of power under steady state with considering power system network topology. An attempt is also made in this paper to develop optimal bidding price structure for the frequency-regulated systems. It gives a signal to traders or bidders that the power demand can be assessed more accurately much closer to real time and helps participants bid more accurate quantities on day-ahead market. The recent trends of frequency linked-price model existing in Indian power systems issues required for attention are also dealt in this paper. Test calculations have been performed on 30-bus system. The paper also explains adoptability of 33 this model to practical Indian power system. The results presented are analyzed and useful conclusions are drawn.

  3. Nuclear Factor E2-Related Factor-2 Negatively Regulates NLRP3 Inflammasome Activity by Inhibiting Reactive Oxygen Species-Induced NLRP3 Priming

    PubMed Central

    Liu, Xiuting; Zhang, Xin; Ding, Yang; Zhou, Wei; Tao, Lei; Lu, Ping; Wang, Yajing

    2017-01-01

    Abstract Aims: The NLRP3 inflammasome is a multiprotein complex that protects hosts against a variety of pathogens. However, the molecular mechanisms of modulating NLRP3 inflammasome activation, especially at the priming step, are still poorly understood. This study was designed to elucidate the negative regulation of nuclear factor E2-related factor-2 (Nrf2) on the activation of NLRP3 inflammasome. Results: We reported that Nrf2 activation inhibited NLRP3 expression, caspase-1 cleavage, and subsequent IL-1β generation. Compared with normal cells, Nrf2-deficient cells showed upregulated cleaved caspase-1, which were attributed to the increased transcription of NLRP3 caused by excess reactive oxygen species (ROS). Furthermore, priming of the NLRP3 inflammasome was sensitive to the exogenous ROS levels induced by H2O2 or rotenone. Combined with adenosine triphosphate, rotenone triggered higher activity of the NLRP3 inflammasome compared with lipopolysaccharide, suggesting that ROS promoted the priming step. In addition, Nrf2-induced NQO1 was involved in the inhibition of the NLRP3 inflammasome. In an in vivo alum-induced peritonitis mouse model, Nrf2 activation suppressed typical IL-1 signaling-dependent inflammation, whereas Nrf2−/− mice exhibited a significant increase in the recruitment of immune cell and the generation of IL-1β compared with wild-type mice. Innovation: We elucidated the effects and possible mechanisms of Nrf2 activation-induced NQO1 expression on NLRP3 inflammasome inactivation and established a novel regulatory role of the Nrf2 pathway in ROS-induced NLRP3 priming. Conclusions: We demonstrated Nrf2 negatively regulating NLRP3 inflammasome activity by inhibiting the priming step and suggested that Nrf2 could be a potential target for some uncontrolled inflammasome activation-associated diseases. Antioxid. Redox Signal. 26, 28–43. PMID:27308893

  4. Reactive oxygen species and nitric oxide regulate mitochondria-dependent apoptosis and autophagy in evodiamine-treated human cervix carcinoma HeLa cells.

    PubMed

    Yang, Jia; Wu, Li-Jun; Tashino, Shin-Ichi; Onodera, Satoshi; Ikejima, Takashi

    2008-05-01

    The redox environment of the cell is currently thought to be extremely important to control either apoptosis or autophagy. This study reported that reactive oxygen species (ROS) and nitric oxide (NO) generations were induced by evodiamine time-dependently; while they acted in synergy to trigger mitochondria-dependent apoptosis by induction of mitochondrial membrane permeabilization (MMP) through increasing the Bax/Bcl-2 or Bcl-x(L) ratio. Autophagy was also stimulated by evodiamine, as demonstrated by the positive autophagosome-specific dye monodansylcadaverine (MDC) staining as well as the expressions of autophagy-related proteins, Beclin 1 and LC3. Pre-treatment with 3-MA, the specific inhibitor for autophagy, dose-dependently decreased cell viability, indicating a survival function of autophagy. Importantly, autophagy was found to be promoted or inhibited by ROS/NO in response to the severity of oxidative stress. These findings could help shed light on the complex regulation of intracellular redox status on the balance of autophagy and apoptosis in anti-cancer therapies.

  5. Ginkgolide B Exerts Cardioprotective Properties against Doxorubicin-Induced Cardiotoxicity by Regulating Reactive Oxygen Species, Akt and Calcium Signaling Pathways In Vitro and In Vivo

    PubMed Central

    Zhao, Deqiang; Zheng, Jianpu; Liu, Zongjun

    2016-01-01

    The aim of this study was to evaluate the effect of Ginkgolide B (GB) on doxorubicin (DOX) induced cardiotoxicity in vitro and in vivo. Rat cardiomyocyte cell line H9c2 was pretreated with GB and subsequently subjected to doxorubicin treatment. Cell viability and cell apoptosis were assessed by MTT assay and Hoechst staining, respectively. Reactive oxygen species (ROS), Akt phosphorylation and intracellular calcium were equally determined in order to explore the underlying molecular mechanism. To verify the in vivo therapeutic effect of GB, we established a mouse model of cardiotoxicity and determined left ventricle ejection fraction (LVEF) and left ventricular mass (LVM). The in vitro experimental results indicated that pretreatment with GB significantly decreases the viability and apoptosis of H9c2 cells by decreasing ROS and intracellular calcium levels and activating Akt phosphorylation. In the in vivo study, we recorded an improved LVEF and a decreased LVM in the group of cardiotoxic rats treated with GB. Altogether, our findings anticipate that GB exerts a cardioprotective effect through possible regulation of the ROS, Akt and calcium pathways. The findings suggest that combination of GB with DOX in chemotherapy could help avoid the cardiotoxic side effects of GB. PMID:27973574

  6. Cell-specific transcriptional regulation and reactivation of galectin-1 gene expression are controlled by DNA methylation of the promoter region.

    PubMed Central

    Benvenuto, G; Carpentieri, M L; Salvatore, P; Cindolo, L; Bruni, C B; Chiariotti, L

    1996-01-01

    The galectin-1 gene is developmentally regulated gene whose activity is strongly modulated during cell differentiation and transformation. We have previously shown that galectin-1 promoter constructs are highly active when transiently transfected in cells both expressing and not expressing the endogenous gene and that the basal activity is determined by a small region encompassing the transcription start site (from positions -50 to +50). We have now investigated the role of DNA methylation in galectin-1 gene expression. Southern blot analysis with HpaII and MspI endonucleases and sodium bisulfite analysis of genomic DNA from expressing and nonexpressing cell lines and cell hybrids showed a close correlation between gene activity and demethylation of the 5' region of the galectin-1 gene. We found that the galectin-1 promoter region is fully methylated, at every CpG site on both strands, in nonexpressing differentiated rat liver (FAO) and thyroid (PC C13) cells and unmethylated in the expressing undifferentiated liver (BRL3A) and thyroid transformed (PC myc/raf) cell lines. In addition, reactivation of the silent FAO alleles in FAO-human osteosarcoma (143tk-) hybrid cells is accompanied by a complete demethylation of the promoter region. Finally, when galectin-1 chloramphenicol acetyltransferase (CAT) promoter constructs were methylated in vitro by SssI methylase at every cytosine residue of the CpG doublets and transfected into mouse fibroblasts, the transcription of the CAT reporter gene was strongly inhibited. PMID:8649381

  7. Regulation of pyruvate dehydrogenase activity and citric acid cycle intermediates during high cardiac power generation.

    PubMed

    Sharma, Naveen; Okere, Isidore C; Brunengraber, Daniel Z; McElfresh, Tracy A; King, Kristen L; Sterk, Joseph P; Huang, Hazel; Chandler, Margaret P; Stanley, William C

    2005-01-15

    A high rate of cardiac work increases citric acid cycle (CAC) turnover and flux through pyruvate dehydrogenase (PDH); however, the mechanisms for these effects are poorly understood. We tested the hypotheses that an increase in cardiac energy expenditure: (1) activates PDH and reduces the product/substrate ratios ([NADH]/[NAD(+)] and [acetyl-CoA]/[CoA-SH]); and (2) increases the content of CAC intermediates. Measurements were made in anaesthetized pigs under control conditions and during 15 min of a high cardiac workload induced by dobutamine (Dob). A third group was made hyperglycaemic (14 mm) to stimulate flux through PDH during the high work state (Dob + Glu). Glucose and fatty acid oxidation were measured with (14)C-glucose and (3)H-oleate. Compared with control, the high workload groups had a similar increase in myocardial oxygen consumption ( and cardiac power. Dob increased PDH activity and glucose oxidation above control, but did not reduce the [NADH]/[NAD(+)] and [acetyl-CoA]/[CoA-SH] ratios, and there were no differences between the Dob and Dob + Glu groups. An additional group was treated with Dob + Glu and oxfenicine (Oxf) to inhibit fatty acid oxidation: this increased [CoA-SH] and glucose oxidation compared with Dob; however, there was no further activation of PDH or decrease in the [NADH]/[NAD(+)] ratio. Content of the 4-carbon CAC intermediates succinate, fumarate and malate increased 3-fold with Dob, but there was no change in citrate content, and the Dob + Glu and Dob + Glu + Oxf groups were not different from Dob. In conclusion, compared with normal conditions, at high myocardial energy expenditure (1) the increase in flux through PDH is regulated by activation of the enzyme complex and continues to be partially controlled through inhibition by fatty acid oxidation, and (2) there is expansion of the CAC pool size at the level of 4-carbon intermediates that is largely independent of myocardial fatty acid oxidation.

  8. The Effect of Hydroelectric Power Plants (hpp) on Agro-Life at Rural Land Regulation in Turkey

    NASA Astrophysics Data System (ADS)

    Onursal Denli, G.; Denli, H. H.; Seker, D. Z.; Bitik, E.; Cetin, S.

    2014-12-01

    Turkey is one of the self-sufficient in foodstuffs and globally ranks as 7th significant agricultural exporter in the world. Main trading partners are the European Union, the United States and the Middle East. As known, agricultural production is dependent on factors including efficient and effective use of all inputs ranging from those natural resources as in land and water to well-trained human resources as labour at the production. The socio-economic aspects of this sector take several forms ranging from the incomes of the primary producers. Rural land regulation is a necessity for rural areas and is regarded as a useful instrument for improving farmer's incomes and life standards. The irrigation system, established during the rural regulation/land consolidation period of large-scale farming, is insufficiently adjusted to the new land tenure structures. The government is especially in the process of water management with hydroelectric power plants. This process produces energy that is required but effects negatively the rivers and agricultural, environmental, climatic conditions. Rivers are vessels of the nature. Free flowing rivers give life to all nature. Most of the studies indicate that Hydroelectric Power Plants (HPP) affects the surface and ground-water management, natural life, agricultural productivity, socio-economic situation at agricultural regions and agro-life related with immigration. This study emphasizes the effect of Hydroelectric Power Plants which are used in transformation of water as a renewable natural resource into electricity power from the perspective of environmental policies and rural regulation.

  9. HCO3−/Cl− Exchange Inactivation and Reactivation during Mouse Oocyte Meiosis Correlates with MEK/MAPK-Regulated Ae2 Plasma Membrane Localization

    PubMed Central

    Zhou, Chenxi; Tiberi, Mario; Liang, Binhui; Alper, Seth L.; Baltz, Jay M.

    2009-01-01

    Background Germinal Vesicle (GV) stage mouse oocytes in first meiotic prophase exhibit highly active HCO3−/Cl− exchange—a class of transport nearly ubiquitously involved in regulation of intracellular pH and cell volume. During meiosis, however, oocyte HCO3−/Cl− exchange becomes inactivated during first metaphase (MI), remains inactive in second metaphase (MII), and is reactivated only after egg activation. Previous work using pharmacological manipulations had indicated that activity of the MEK/MAPK signaling pathway was negatively correlated with HCO3−/Cl− exchange activity during meiosis. However, the mechanism by which the exchanger is inactivated during meiotic progression had not been determined, nor had the role of MEK/MAPK been directly established. Methodology/Principal Findings Expression of a constitutively active form of MEK (MAP kinase kinase), which prevented the normal downregulation of MAPK after egg activation, also prevented reactivation of HCO3−/Cl− exchange. Conversely, suppression of endogenous MAPK activity with dominant negative MEK activated the normally quiescent HCO3−/Cl− exchange in mature MII eggs. A GFP-tagged form of the HCO3−/Cl− exchanger isoform Ae2 (Slc4a2) was strongly expressed at the GV oocyte plasma membrane, but membrane localization decreased markedly during meiotic progression. A similar pattern for endogenous Ae2 was confirmed by immunocytochemistry. The loss of membrane-localized Ae2 appeared selective, since membrane localization of a GFP-tagged human dopamine D1 receptor did not change during meiotic maturation. Conclusions Direct manipulation of MAPK activity indicated that GFP-tagged Ae2 localization depended upon MAPK activity. Inactivation of HCO3−/Cl− exchange during the meiotic cell cycle may therefore reflect the loss of Ae2 from the oocyte plasma membrane, downstream of MEK/MAPK signaling. This identifies a novel role for MEK/MAPK-mediated cytostatic factor (CSF) activity during

  10. The Aspergillus fumigatus transcriptional regulator AfYap1 represents the major regulator for defense against reactive oxygen intermediates but is dispensable for pathogenicity in an intranasal mouse infection model.

    PubMed

    Lessing, Franziska; Kniemeyer, Olaf; Wozniok, Iwona; Loeffler, Juergen; Kurzai, Oliver; Haertl, Albert; Brakhage, Axel A

    2007-12-01

    Macrophages and neutrophils kill the airborne fungal pathogen Aspergillus fumigatus. The dependency of this killing process on reactive oxygen intermediates (ROI) has been strongly suggested. Therefore, we investigated the enzymatic ROI detoxifying system by proteome analysis of A. fumigatus challenged by H(2)O(2). Since many of the identified proteins and genes are apparently regulated by a putative Saccharomyces cerevisiae Yap1 homolog, the corresponding gene of A. fumigatus was identified and designated Afyap1. Nuclear localization of a functional AfYap1-eGFP fusion was stress dependent. Deletion of the Afyap1 gene led to drastically increased sensitivity of the deletion mutant against H(2)O(2) and menadione, but not against diamide and NO radicals. Proteome analysis of the DeltaAfyap1 mutant strain challenged with 2 mM H(2)O(2) indicated that 29 proteins are controlled directly or indirectly by AfYap1, including catalase 2. Despite its importance for defense against reactive agents, the Afyap1 deletion mutant did not show attenuated virulence in a murine model of Aspergillus infection. These data challenge the hypothesis that ROI such as superoxide anions and peroxides play a direct role in killing of A. fumigatus in an immunocompromised host. This conclusion was further supported by the finding that killing of A. fumigatus wild-type and DeltaAfyap1 mutant germlings by human neutrophilic granulocytes worked equally well irrespective of whether the ROI scavenger glutathione or an NADPH-oxidase inhibitor was added to the cells.

  11. Phosphoprotein Regulation of Synaptic Reactivity

    DTIC Science & Technology

    1993-07-07

    carried by Na+, we sought to record the isolated Na+ current by application of external Mg2 +, internal F- and tetraethylammonium ( TEA ), and the...removal of external Na+, and was unaffected by application of external TEA . Application of the c-FAs oleate, linoleate, and linolenate reversibly...90, 1987) by studying LTP in the anesthetized male albino mouse injecting cycloheximide (CXM) or anisomycin (ANI) subcutaneously 30 min or 4 hr prior

  12. Phosphoprotein Regulation of Behavioral Reactivity

    DTIC Science & Technology

    1990-07-17

    kinase C in information storage. In: R.J. Wurtman, S. Corkin and J. Growden (Eds.). " Alzheimer’s Disease : Advances in Basic Research and Therapies...Wurtman, S. Corkin and J. Growden (Eds.). " Alzheimer’s Disease : Advances in Basic Research and Therapies". Suppl. 24, New York: Springer-Verlag, 1987...34 Gif s/Yvette, France, October 3-5, 1990. (Dr. Michel Baudry) 26. Routtenberg, A. Invited speaker. Symposium on " Alzheimer’s Disease : Status of Clinical

  13. An Set-Free, All Digital Controlled Point-of-Load Regulator for Next Generation Power Systems: ADC-POL

    NASA Technical Reports Server (NTRS)

    Adell, Philippe C.; Liu, Tao; Vermeire, Bert; Bakkaloglu, Bertan; Aveline, David

    2011-01-01

    This paper presents a digitally controlled programmable point-of-load regulator for next-generation power systems. A novel digital control scheme was designed to minimize single-event effect (SEE)-induced transient effects. By effectively programming the loop transmission, the POL can trade off transient response time with SET robustness. The IC works with 1 to 5.5 V input voltage, 1-4.5V regulated output voltage, high efficiency (peak efficiency at 94%) and power of up to 5 W. The design was fabricated in the AMI i2t100 0.7 mu m complimentary, metal-oxide semiconductor (CMOS) process and characterized with the Jet Propulsion Laboratory (JPL) pulsed laser system.

  14. The physics of power systems operation

    NASA Astrophysics Data System (ADS)

    Ohler, C.

    2015-08-01

    The article explains the operation of power systems from the point of view of physics. Physicists imagine things, rather than in terms of impedances and circuits, in terms of fields and energy conversions. The account is concrete and simple. The use of alternating current entails the issue of reactive power. Reactive power consists of energy that oscillates between electrical and magnetic fields, it flows on top of the active power which carries the useful energy. The control of active and reactive power is essential for the power system's reliable operation. The frequency of a power system is the same everywhere. The stability of the frequency indicates that generation and demand of active power are equal, a decline in frequency indicates a lack of generation relative to the demand. Adapting the electrical power injected into the system is the way of frequency control. Because of the parasitic inductances and capacitances of overhead lines, cables, and transformers, the voltage at different locations of the power system depends on the load. The voltage is regulated by the combined action of generator excitation, transformer tap changers and series compensation in order to provide consumers with a stable voltage supply. The integration of solar cells and wind turbines into the power system poses some challenges. But the power system is able to accommodate large amounts of fluctuating renewable power generation if the right complementary measures are taken.

  15. [Polish regulations on maximum admissible intensities for electric and magnetic frequencies of 60 Hz and the European Union recommendations for electrical power engineering].

    PubMed

    Groszko, Marian

    2003-01-01

    Electric and magnetic fields of 50 Hz from electric power devices affect not only workers, but also the general population, as these devices are also located in populated areas, hence the duality of regulations on maximum admissible intensities. This paper presents these regulations and discusses in detail the changes of 2001. Based on the Polish regulations, hygienic evaluation of electric power devices has been attempted. The Polish regulations on the 50 Hz electromagnetic fields were compared with relevant international regulations of CENELEC and the European Union recommendations. Our maximum admissible intensities have been found to conform with the international standards.

  16. Distributed Control of Inverter-Based Lossy Microgrids for Power Sharing and Frequency Regulation Under Voltage Constraints

    SciTech Connect

    Chang, Chin-Yao; Zhang, Wei

    2016-01-19

    This paper presents a new distributed control framework to coordinate inverter-interfaced distributed energy resources (DERs) in island microgrids. We show that under bounded load uncertainties, the proposed control method can steer the microgrid to a desired steady state with synchronized inverter frequency across the network and proportional sharing of both active and reactive powers among the inverters. We also show that such convergence can be achieved while respecting constraints on voltage magnitude and branch angle differences. The controller is robust under various contingency scenarios, including loss of communication links and failures of DERs. The proposed controller is applicable to lossy mesh microgrids with heterogeneous R/X distribution lines and reasonable parameter variations. Simulations based on various microgrid operation scenarios are also provided to show the effectiveness of the proposed control method.

  17. Power management and frequency regulation for microgrid and smart grid: A real-time demand response approach

    NASA Astrophysics Data System (ADS)

    Pourmousavi Kani, Seyyed Ali

    Future power systems (known as smart grid) will experience a high penetration level of variable distributed energy resources to bring abundant, affordable, clean, efficient, and reliable electric power to all consumers. However, it might suffer from the uncertain and variable nature of these generations in terms of reliability and especially providing required balancing reserves. In the current power system structure, balancing reserves (provided by spinning and non-spinning power generation units) usually are provided by conventional fossil-fueled power plants. However, such power plants are not the favorite option for the smart grid because of their low efficiency, high amount of emissions, and expensive capital investments on transmission and distribution facilities, to name a few. Providing regulation services in the presence of variable distributed energy resources would be even more difficult for islanded microgrids. The impact and effectiveness of demand response are still not clear at the distribution and transmission levels. In other words, there is no solid research reported in the literature on the evaluation of the impact of DR on power system dynamic performance. In order to address these issues, a real-time demand response approach along with real-time power management (specifically for microgrids) is proposed in this research. The real-time demand response solution is utilized at the transmission (through load-frequency control model) and distribution level (both in the islanded and grid-tied modes) to provide effective and fast regulation services for the stable operation of the power system. Then, multiple real-time power management algorithms for grid-tied and islanded microgrids are proposed to economically and effectively operate microgrids. Extensive dynamic modeling of generation, storage, and load as well as different controller design are considered and developed throughout this research to provide appropriate models and simulation

  18. "Power, Regulation and Physically Active Identities": The Experiences of Rural and Regional Living Adolescent Girls

    ERIC Educational Resources Information Center

    Casey, M.; Mooney, A.; Smyth, J.; Payne, W.

    2016-01-01

    Drawing on interpretations of Foucault's techniques of power, we explored the discourses and power relations operative between groups of girls that appeared to influence their participation in Physical Education (PE) and outside of school in sport and physical activity (PA) in rural and regional communities. Interviews and focus groups were…

  19. Interactions of C-Reactive Protein and Serum Amyloid P Component with Interleukin-8 and Their Role in Regulation of Neutrophil Functions.

    PubMed

    Galkina, Elena V.; Nazarov, Peter G.; Polevschikov, Alexander V.; Berestovaya, Larissa K.; Galkin, Vitold E.; Bychkova, Natalia V.

    2000-12-01

    C-reactive protein (CRP) and serum amyloid P component (SAP) are acute phase proteins, whose concentrations increase within 24 h of inflammation along with concentration of IL-8. Polymorphonuclear neutrophil leukocytes (PMNs) form the earliest barrier protecting an injured organ during acute phase response. The aim of present work was to study interactions between CRP, SAP and IL-8, and to estimate the role of these interactions in regulation of neutrophil transendothelial migration. The results have shown that IL-8 binds to immobilized but not to free CRP. Binding of IL-8 to immobilized SAP was less strong. SAP like IL-8 increased CD11/CD18 integrin expression. IL-8 did not abolish the effect of SAP, and the mixture of IL-8 and SAP has stimulated CD11/CD18 expression. CRP upregulated CD18 but not CD11b expression. Under simultaneous action of CRP and IL-8, the stimulatory effect on CD11b and CD18 was abolished. The expression of fibronectin receptor was reduced by either IL-8 or CRP but increased by SAP. Effect of each protein was downregulated after following preincubations: CRP+SAP, CRP+IL-8 or SAP+IL-8. The mixtures of CRP with SAP, CRP with IL-8 or SAP with IL-8 showed no chemotactic activity, although each of the proteins was chemoattractive. Thus, acute phase proteins and IL-8 can act as anti-inflammatory factors upon binding each other. In summary, CRP and SAP influence PMN adhesion, migration and expression of CD11b/CD18 and fibronectin receptors, and can modulate the action of IL-8 on PMN attachment to endothelium and fibronectin, and on PMN traffic through the extracellular matrix during transendothelial migration.

  20. mGluR5 in the nucleus accumbens shell regulates morphine-associated contextual memory through reactive oxygen species signaling.

    PubMed

    Qi, Chong; Wang, Xinjuan; Ge, Feifei; Li, Yijing; Shen, Fang; Wang, Junkai; Cui, Cailian

    2015-09-01

    Emerging evidence indicates that metabotropic glutamate receptor 5 (mGluR5) critically modulates drug and drug-related behaviors. However, the role of mGluR5 in the opiate-induced contextual memory remains unclear. Here, we found that microinfusion of the mGluR5 antagonist 3-((2-Methyl-1,3-thiazol-4-yl)ethynyl)pyridine (MTEP) into the nucleus accumbens (NAc) shell, but not into the core, significantly attenuated the expression of morphine conditioned place preference (CPP) in rats. Following the expression of morphine CPP, the protein level of membrane mGluR5 was selectively increased in the NAc shell. In primary striatal neurons, we observed that treatment with the mGluR5 agonist CHPG increased the phosphorylation level of extracellular signal-regulated kinase (ERK), which was dependent on the mGluR5-inositol-1,4,5-trisphosphate-reactive oxygen species (ROS) pathway. Moreover, the microinjection of the ROS scavenger Tempol into the NAc shell of rats blocked the expression of morphine CPP. Further, the administration of t-BOOH, a ROS donor, into the NAc shell rescued the retrieval impairment of morphine CPP produced by MTEP. Our previous study demonstrated that the expression of morphine CPP increased the phosphorylation of ERK selectively in the NAc shell. Thus, results of the present study suggest that mGluR5 in the NAc shell, but not in the core, is essential for the retrieval of morphine contextual memory, which is mediated at least in part, through the ROS/ERK signaling pathway. Uncovering the molecular basis of opiate contextual memory will benefit the development of new therapeutic approaches for the treatment of opiate addiction.

  1. Power Quality Aspects in a Wind Power Plant

    SciTech Connect

    Muljadi, E.; Butterfield, C. P.; Chacon, J.; Romanowitz, H.

    2006-01-01

    Like conventional power plants, wind power plants must provide the power quality required to ensure the stability and reliability of the power system it is connected to and to satisfy the customers connected to the same grid. When wind energy development began, wind power plants were very small, ranging in size from under one megawatt to tens megawatts with less than 100 turbines in each plant. Thus, the impact of wind power plant on the grid was very small, and any disturbance within or created by the plant was considered to be in the noise level. In the past 30 years, the size of wind turbines and the size of wind power plants have increased significantly. Notably, in Tehachapi, California, the amount of wind power generation has surpassed the infrastructure for which it was designed. At the same time, the lack of rules, standards, and regulations during early wind development has proven to be an increasing threat to the stability and power quality of the grid connected to a wind power plant. Fortunately, many new wind power plants are equipped with state of the art technology, which enables them to provide good service while producing clean power for the grid. The advances in power electronics have allowed many power system applications to become more flexible and to accomplish smoother regulation. Applications such as reactive power compensation, static transfer switches, energy storage, and variable-speed generations are commonly found in modern wind power plants. Although many operational aspects affect wind power plant operation, this paper, focuses on power quality. Because a wind power plant is connected to the grid, it is very important to understand the sources of disturbances that affect the power quality. In general, the voltage and frequency must be kept as stable as possible. The voltage and current distortions created by harmonics will also be discussed in this paper as will self-excitation, which may occur in a wind power plant due to loss of line.

  2. The balance of powers: Redox regulation of fibrogenic pathways in kidney injury

    PubMed Central

    Okamura, Daryl M.; Pennathur, Subramaniam

    2015-01-01

    Oxidative stress plays a central role in the pathogenesis of diverse chronic inflammatory disorders including diabetic complications, cardiovascular disease, aging, and chronic kidney disease (CKD). Patients with moderate to advanced CKD have markedly increased levels of oxidative stress and inflammation that likely contribute to the unacceptable high rates of morbidity and mortality in this patient population. Oxidative stress is defined as an imbalance of the generation of reactive oxygen species (ROS) in excess of the capacity of cells/tissues to detoxify or scavenge them. Such a state of oxidative stress may alter the structure/function of cellular macromolecules and tissues that eventually leads to organ dysfunction. The harmful effects of ROS have been largely attributed to its indiscriminate, stochastic effects on the oxidation of protein, lipids, or DNA but in many instances the oxidants target particular amino acid residues or lipid moieties. Oxidant mechanisms are intimately involved in cell signaling and are linked to several key redox-sensitive signaling pathways in fibrogenesis. Dysregulation of antioxidant mechanisms and overproduction of ROS not only promotes a fibrotic milieu but leads to mitochondrial dysfunction and further exacerbates kidney injury. Our studies support the hypothesis that unique reactive intermediates generated in localized microenvironments of vulnerable tissues such as the kidney activate fibrogenic pathways and promote end-organ damage. The ability to quantify these changes and assess response to therapies will be pivotal in understanding disease mechanisms and monitoring efficacy of therapy. PMID:26448394

  3. The unified power flow controller: A new approach to power transmission control

    SciTech Connect

    Gyugyi, L.; Schauder, C.D.; Williams, S.L.; Rietman, T.R.; Torgerson, D.R.; Edris, A.

    1995-04-01

    This paper shows that the Unified Power Flow Controller (UPFC) is able to control both the transmitted real power and, independently, the reactive power flows at the sending-and the receiving-end of the transmission line. The unique capabilities of the UPFC in multiple line compensation are integrated into a generalized power flow controller that is able to maintain prescribed, and independently controllable, real power and reactive power flow in the line. The paper describes the basic concepts of the proposed generalized P and Q controller and compares it to the more conventional, but related power flow controller, such as the Thyristor-Controlled Series Capacitor and Thyristor-Controlled Phase Angle Regulator. The paper also presents results of computer simulations showing the performance of the UPFC under different system conditions.

  4. Temperature effect on the chemomechanical regulation of substeps within the power stroke of a single Myosin II

    PubMed Central

    Dong, Chenling; Chen, Bin

    2016-01-01

    Myosin IIs in the skeletal muscle are highly efficient nanoscale machines evolved in nature. Understanding how they function can not only bring insights into various biological processes but also provide guidelines to engineer synthetic nanoscale motors working in the vicinity of thermal noise. Though it was clearly demonstrated that the behavior of a skeletal muscle fiber, or that of a single myosin was strongly affected by the temperature, how exactly the temperature affects the kinetics of a single myosin is not fully understood. By adapting the newly developed transitional state model, which successfully explained the intriguing motor force regulation during skeletal muscle contraction, here we systematically explain how exactly the power stroke of a single myosin proceeds, with the consideration of the chemomechanical regulation of sub-steps within the stroke. The adapted theory is then utilized to investigate the temperature effect on various aspects of the power stroke. Our analysis suggests that, though swing rates, the isometric force, and the maximal stroke size all strongly vary with the temperature, the temperature can have a very small effect on the releasable elastic energy within the power stroke. PMID:26786569

  5. Power

    SciTech Connect

    1999-10-01

    Subjects covered in this section are: (1) CP and L, Florida Progress to create new company through merger; (2) Violations are color-coded under new NRC enforcement policy; (3) NRC confirms that nuclear plants are Y2K ready; (4) NIRS denied NRC ruling; (5) NRC to allow lower insurance coverage on shutdown TMI-2; (6) NRC look to change noncombustibility regulation; and (7) Electronic NRC reading room scheduled to open.

  6. Prognostic health monitoring in switch-mode power supplies with voltage regulation

    NASA Technical Reports Server (NTRS)

    Hofmeister, James P (Inventor); Judkins, Justin B (Inventor)

    2009-01-01

    The system includes a current injection device in electrical communication with the switch mode power supply. The current injection device is positioned to alter the initial, non-zero load current when activated. A prognostic control is in communication with the current injection device, controlling activation of the current injection device. A frequency detector is positioned to receive an output signal from the switch mode power supply and is able to count cycles in a sinusoidal wave within the output signal. An output device is in communication with the frequency detector. The output device outputs a result of the counted cycles, which are indicative of damage to an a remaining useful life of the switch mode power supply.

  7. Regulating glottal airflow in phonation: Application of the maximum power transfer theorem to a low dimensional phonation model

    NASA Astrophysics Data System (ADS)

    Titze, Ingo R.

    2002-01-01

    Two competing views of regulating glottal airflow for maximum vocal output are investigated theoretically. The maximum power transfer theorem is used as a guide. A wide epilarynx tube (laryngeal vestibule) matches well with low glottal resistance (believed to correspond to the ``yawn-sigh'' approach in voice therapy), whereas a narrow epilarynx tube matches well with a higher glottal resistance (believed to correspond to the ``twang-belt'' approach). A simulation model is used to calculate mean flows, peak flows, and oral radiated pressure for an impedance ratio between the vocal tract (the load) and the glottis (the source). Results show that when the impedance ratio approaches 1.0, maximum power is transferred and radiated from the mouth. A full update of the equations used for simulating driving pressures, glottal flow, and vocal tract input pressures is provided as a programming guide for those interested in model development.

  8. Preliminary Performance Data on Westinghouse Electronic Power Regulator Operating on J34-WE-32 Turbojet Engine in Altitude Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Ketchum, James R.; Blivas, Darnold; Pack, George J.

    1950-01-01

    The behavior of the Westinghouse electronic power regulator operating on a J34-WE-32 turbojet engine was investigated in the NACA Lewis altitude wind tunnel at the request of the Bureau of Aeronautics, Department of the Navy. The object of the program was to determine the, steady-state stability and transient characteristics of the engine under control at various altitudes and ram pressure ratios, without afterburning. Recordings of the response of the following parameters to step changes in power lever position throughout the available operating range of the engine were obtained; ram pressure ratio, compressor-discharge pressure, exhaust-nozzle area, engine speed, turbine-outlet temperature, fuel-valve position, jet thrust, air flow, turbine-discharge pressure, fuel flow, throttle position, and boost-pump pressure. Representative preliminary data showing the actual time response of these variables are presented. These data are presented in the form of reproductions of oscillographic traces.

  9. 47 CFR 74.780 - Broadcast regulations applicable to translators, low power, and booster stations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... transmitters. Section 73.658—Affiliation agreements and network program practices; territorial exclusivity in non-network program arrangements. Part 73, Subpart G—Emergency Broadcast System (for low power TV.... Section 73.1692—Construction near or installations on an AM broadcast tower. Section 73.1940—Broadcasts...

  10. Congress, the FCC and Children's Television Regulation: A Shift in the Balance of Power.

    ERIC Educational Resources Information Center

    Markin, Karen

    The Federal Communications Commission (FCC) of the late 1980s appeared to pursue its own agenda of broadcast deregulation, notwithstanding congressional pressures. The apparent power shift is evident in a case study of the interactions between Congress and the FCC on the subject of children's television. In the early 1970s, the FCC tended to…

  11. Reactivity effects in VVER-1000 of the third unit of the kalinin nuclear power plant at physical start-up. Computations in ShIPR intellectual code system with library of two-group cross sections generated by UNK code

    SciTech Connect

    Zizin, M. N.; Zimin, V. G.; Zizina, S. N. Kryakvin, L. V.; Pitilimov, V. A.; Tereshonok, V. A.

    2010-12-15

    The ShIPR intellectual code system for mathematical simulation of nuclear reactors includes a set of computing modules implementing the preparation of macro cross sections on the basis of the two-group library of neutron-physics cross sections obtained for the SKETCH-N nodal code. This library is created by using the UNK code for 3D diffusion computation of first VVER-1000 fuel loadings. Computation of neutron fields in the ShIPR system is performed using the DP3 code in the two-group diffusion approximation in 3D triangular geometry. The efficiency of all groups of control rods for the first fuel loading of the third unit of the Kalinin Nuclear Power Plant is computed. The temperature, barometric, and density effects of reactivity as well as the reactivity coefficient due to the concentration of boric acid in the reactor were computed additionally. Results of computations are compared with the experiment.

  12. Single-cell epigenomics: powerful new methods for understanding gene regulation and cell identity.

    PubMed

    Clark, Stephen J; Lee, Heather J; Smallwood, Sébastien A; Kelsey, Gavin; Reik, Wolf

    2016-04-18

    Emerging single-cell epigenomic methods are being developed with the exciting potential to transform our knowledge of gene regulation. Here we review available techniques and future possibilities, arguing that the full potential of single-cell epigenetic studies will be realized through parallel profiling of genomic, transcriptional, and epigenetic information.

  13. The Power of Social and Motivational Relationships for Test-Anxious Adolescents' Academic Self-Regulation

    ERIC Educational Resources Information Center

    Raufelder, Diana; Hoferichter, Frances; Schneeweiss, David; Wood, Megan A.

    2015-01-01

    Based on cognitive evaluation theory (CET) and organismic integration theory (OIT)--both sub-theories of self-determination theory (SDT)--the present study examined whether the academic self-regulation of youth with test anxiety can be strengthened through social and motivational relationships with peers and teachers. This study employed a large…

  14. Teaching Glycosis Regulation to Undergraduates Using An Electrical Power Generation Analogy

    ERIC Educational Resources Information Center

    Stavrianeas, Stasinos

    2005-01-01

    Biology, physiology, and allied health biochemistry textbooks cover metabolic pathways such as glycolysis; however, most do not include much discussion of how these pathways are regulated within the cell. Because the details of these complex regulatory processes can be difficult for students to learn, we have developed a robust teaching…

  15. Skylab reactivation mission report

    NASA Technical Reports Server (NTRS)

    Chubb, W. B.

    1980-01-01

    On July 11, 1979, Skylab impacted the Earth's surface. The debris dispersion area stretched from the South Eastern Indian Ocean across a sparsely populated section of Western Australia. The events leading to the reentry of Skylab are discussed and a final assessment of the Skylab debris impact footprint is presented. Also included are detailed evaluations of the various Skylab systems that were reactivated when control of Skylab was regained in mid-1978 after having been powered down since February 4, 1974.

  16. Reactive sintering and reactive hot

    NASA Astrophysics Data System (ADS)

    Murray, J. C.; German, R. M.

    1992-09-01

    NbAl3 has been synthesized from elemental powders by reactive sintering (RS) and reactive hot isostatic pressing (RHIP). Both processes involve a self-propagating exothermic reaction between the constituent powders to form an intermetallic compound. The RHIP approach uses simultaneous external pressurization to make a higher density product. This study focused on developing a method to use reactive synthesis to form high-density NbAl3 compacts. High RS and RHIP densities were possible with the appropriate raw materials and processing parameters. These include powder purity, particle sizes, degassing, heating rate, furnace temperature, and compaction pressures. Near full density was attained with RHIP, and up to 95 pct density was attained with RS.

  17. Safety and licensing for small and medium power reactors

    SciTech Connect

    Trauger, D.B.

    1987-01-01

    Proposed new concepts for small and medium power reactors differ substantially from traditional Light Water Reactors (LWRs). Although designers have a large base of experience in safety and licensing, much of it is not relevant to new concepts. It can be a disadvantage if regulators apply LWR rules directly. A fresh start is appropriate. The extensive interactions between industry, regulators, and the public complicates but may enhance safety. It is basic to recognize the features that distinguish nuclear energy safety from that for other industries. These features include: nuclear reactivity, fission product radiation, and radioactive decay heat. Small and medium power reactors offer potential advantages over LWRs, particularly for reactivity and decay heat.

  18. Combining the Power of Irmpd with Ion-Molecule Reactions: the Structure and Reactivity of Radical Ions of Cysteine and its Derivatives

    NASA Astrophysics Data System (ADS)

    Lesslie, Michael; Osburn, Sandra; Berden, Giel; Oomens, J.; Ryzhov, Victor

    2015-06-01

    Most of the work on peptide radical cations has involved protons as the source of charge. Nonetheless, using metal ions as charge sources often offers advantages like stabilization of the structure via multidentate coordination and the elimination of the "mobile proton". Moreover, characterization of metal-bound amino acids is of general interest as the interaction of peptide side chains with metal ions in biological systems is known to occur extensively. In the current study, we generate thiyl radicals of cysteine and homocysteine in the gas phase complexed to alkali metal ions. Subsequently, we utilize infrared multiple-photon dissociation (IRMPD) and ion-molecule reactions (IMR) to characterize the structure and reactivity of these radical ions. Our group has worked extensively with the cysteine-based radical cations and anions, characterizing the gas-phase reactivity and rearrangement of the amino acid and several of its derivatives. In a continuation of this work, we are perusing the effects of metal ions as the charge bearing species on the reactivity of the sulfur radical. Our S-nitroso chemistry can easily be used in conjunction with metal ion coordination to produce initial S-based radicals in peptide radical-metal ion complexes. In all cases we have been able to achieve radical formation with significant yield to study reactivity. Ion-molecule reactions of metallated radicals with allyl iodide, dimethyl disulfide, and allyl bromide have all shown decreasing reactivity going down group 1A. Recently, we determined the experimental IR spectra for the homocysteine radical cation with Li+, Na+, and K+ as the charge bearing species at the FELIX facility. For comparison, the protonated IR spectrum of homocysteine has previously been obtained by our group. A preliminary match of the IR spectra has been confirmed. Finally, calculations are underway to determine the bond distances of all the metal adduct structures.

  19. Change-in-law provisions in a carbon-constrained America: the impact of carbon regulation on long-term power purchase agreements

    SciTech Connect

    Harms, Brian C.

    2009-06-15

    Policymakers now are acting on climate change initiatives. As new regulations are discussed, adopted, and applied to power plants, sellers and buyers of power will have to negotiate the appropriate risk allocation, both in terms of price and passthrough of costs. (author)

  20. High power valve regulated lead-acid batteries for new vehicle requirements

    NASA Astrophysics Data System (ADS)

    Trinidad, Francisco; Sáez, Francisco; Valenciano, Jesús

    The performance of high power VRLA ORBITAL™ batteries is presented. These batteries have been designed with isolated cylindrical cells, providing high reliability to the recombination process, while maintaining, at the same time, a very high compression (>80 kPa) over the life of the battery. Hence, the resulting VRLA modules combine a high rate capability with a very good cycle performance. Two different electrochemically active material compositions have been developed: high porosity and low porosity for starting and deep cycle applications, respectively (depending on the power demand and depth of discharge). Although, the initial performance of the starting version is higher, after a few cycles the active material of the deep cycle version is fully developed, and this achieves the same high rate capability. Both types are capable of supplying the necessary reliability for cranking at the lowest temperature (-40°C). Specific power of over 500 W/kg is achievable at a much lower cost than for nickel-metal hydride systems. Apart from the initial performance, an impressive behaviour of the cycling version has been found in deep cycle applications, due to the highly compressed and high density active material. When submitted to continuous discharge-charge cycles at 75% (IEC 896-2 specification) and 100% (BCI deep cycle) DoD, it has been found that the batteries are still healthy after more than 1000 and 700 cycles, respectively. However, it has been proven that the application of an IUi algorithm (up to 110% of overcharging) with a small constant current charging period at the end of the charge is absolutely necessary to achieve the above results. Without the final boosting period, the cycle life of the battery could be substantially shortened. The high specific power and reliability observed in the tests carried out, would allow ORBITAL™ batteries to comply with the more demanding requirements that are being introduced in conventional and future hybrid electric

  1. Applicability of the PSD Regulations to Powerplants that are Certified by DOE as Peakload Power Plants

    EPA Pesticide Factsheets

    This document may be of assistance in applying the New Source Review (NSR) air permitting regulations including the Prevention of Significant Deterioration (PSD) requirements. This document is part of the NSR Policy and Guidance Database. Some documents in the database are a scanned or retyped version of a paper photocopy of the original. Although we have taken considerable effort to quality assure the documents, some may contain typographical errors. Contact the office that issued the document if you need a copy of the original.

  2. Baccharis trimera inhibits reactive oxygen species production through PKC and down-regulation p47 (phox) phosphorylation of NADPH oxidase in SK Hep-1 cells.

    PubMed

    de Araújo, Glaucy Rodrigues; Rabelo, Ana Carolina Silveira; Meira, Janaína Serenato; Rossoni-Júnior, Joamyr Victor; Castro-Borges, William de; Guerra-Sá, Renata; Batista, Maurício Azevedo; Silveira-Lemos, Denise da; Souza, Gustavo Henrique Bianco de; Brandão, Geraldo Célio; Chaves, Míriam Martins; Costa, Daniela Caldeira

    2017-02-01

    Baccharis trimera, popularly known as "carqueja", is a native South-American plant possessing a high concentration of polyphenolic compounds and therefore high antioxidant potential. Despite the antioxidant potential described for B. trimera, there are no reports concerning the signaling pathways involved in this process. So, the aim of the present study was to assess the influence of B. trimera on the modulation of PKC signaling pathway and to characterize the effect of the nicotinamide adenine dinucleotide phosphate oxidase enzyme (NOX) on the generation of reactive oxygen species in SK Hep-1 cells. SK-Hep 1 cells were treated with B. trimera, quercetin, or rutin and then stimulated or not with PMA/ionomycin and labeled with carboxy H2DCFDA for detection of reactive oxygen species by flow cytometer. The PKC expression by Western blot and enzyme activity was performed to evaluate the influence of B. trimera and quercetin on PKC signaling pathway. p47 (phox) and p47 (phox) phosphorylated expression was performed by Western blot to evaluate the influence of B. trimera on p47 (phox) phosphorylation. The results showed that cells stimulated with PMA/ionomycin (activators of PKC) showed significantly increased reactive oxygen species production, and this production returned to baseline levels after treatment with DPI (NOX inhibitor). Both B. trimera and quercetin modulated reactive oxygen species production through the inhibition of PKC protein expression and enzymatic activity, also with inhibition of p47 (phox) phosphorylation. Taken together, these results suggest that B. trimera has a potential mechanism for inhibiting reactive oxygen species production through the PKC signaling pathway and inhibition subunit p47 (phox) phosphorylation of nicotinamide adenine dinucleotide phosphate oxidase.

  3. Body-building without power training: endogenously regulated pectoral muscle hypertrophy in confined shorebirds

    PubMed

    Dietz; Piersma; Dekinga

    1999-10-01

    Shorebirds such as red knots Calidris canutus routinely make migratory flights of 3000 km or more. Previous studies on this species, based on compositional analyses, suggest extensive pectoral muscle hypertrophy in addition to fat storage before take-off. Such hypertrophy could be due to power training and/or be effected by an endogenous circannual rhythm. Red knots of two subspecies with contrasting migration patterns were placed in a climate-controlled aviary (12 h:12 h L:D photoperiod) where exercise was limited. Using ultrasonography, we measured pectoral muscle size as the birds stored fat in preparation for migration. At capture, there were no differences in body mass and pectoral muscle mass between the two subspecies. As they prepared for southward and northward migration, respectively, the tropically wintering subspecies (C. c. canutus) gained 31 g and the temperate wintering subspecies (C. c. islandica) gained 41 g. During this time, pectoral mass increased by 43-44 % of initial mass, representing 39 % (C. c. canutus) and 29 % (C. c. islandica) of the increase in body mass. The gizzard showed atrophy in conjunction with a diet change from molluscs to food pellets. Although we cannot exclude the possibility that the birds' limited movement may still be a prerequisite for pectoral muscle hypertrophy, extensive power training is certainly not a requirement. Muscle hypertrophy in the absence of photoperiod cues suggests the involvement of an endogenous circannual process.

  4. TRAF3 as a powerful and multitalented regulator of lymphocyte functions.

    PubMed

    Bishop, Gail A

    2016-11-01

    This review summarizes the current state of knowledge regarding the roles of the signaling adapter protein tumor necrosis factor receptor (TNFR)-associated factor 3 in regulating the functions of B and T lymphocytes. In B lymphocytes, TNFR-associated factor 3 inhibits signaling by TNFR superfamily receptors, Toll-like receptors, and interleukin-6R. In contrast, signaling to B cells by the virally encoded oncogenic protein latent membrane protein 1 is promoted by TNFR-associated factor 3. An important B cell-specific role for TNFR-associated factor 3 is the inhibition of homeostatic survival, directly relevant to the common occurrence of TNFR-associated factor 3 mutations in human B cell malignancies. TNFR-associated factor 3 was recently found to be a resident nuclear protein in B cells, where it interacts with and inhibits gene expression mediated by the cAMP response element-binding protein transcription complex, including expression of the prosurvival protein myeloid leukemia cell differentiation protein 1. In T lymphocytes, TNFR-associated factor 3 is required for normal signaling by the T cell antigen receptor, while inhibiting signaling by the interleukin-2 receptor. Cytoplasmic TNFR -associated factor 3 restrains nuclear factor-κB2 activation in both T and B cells. Clinical implications and future directions for the study of this context-dependent signaling regulator are discussed.

  5. A powerful hybrid puc operon promoter tightly regulated by both IPTG and low oxygen level.

    PubMed

    Hu, Zongli; Zhao, Zhiping; Pan, Yu; Tu, Yun; Chen, Guoping

    2010-04-01

    Rhodobacter sphaeroides has been intensively studied and provides an excellent model for studying both photosynthesis and membrane development. The photosynthetic apparatus (LH2 and LH1-RC complexes) can be synthesized in large scale and integrated into the intracytoplasmic membrane system under specific conditions, which thus provides us insight to utilize the puc or(and) puf operon to heterologously express recombinant proteins in the intracytoplasmic membrane using Rb. sphaeroides as a novel expression system. However, basal level of expression of puc and puf promoter is uncontrolled. We report the construction of LH2 polypeptide expression vector that contains a reengineered lacI(q)-puc promoter-lac operator hybrid promoter, which allows the puc operon to be regulated by both IPTG and low oxygen level. Synthesis of LH2 complexes was completely repressed in the absence of isopropyl beta-D-thiogalactoside (IPTG), and the degree of induction was controlled by varying the concentration of IPTG. The optimal concentration of IPTG was determined. SDS-PAGE and Western blot were employed for further analysis. Our results suggest that the reengineered hybrid promoter is efficient to tightly regulate the expression of the puc operon, and our strategy can open up a new approach in the study of the membrane protein expression system.

  6. Distributed Hierarchical Control of Multi-Area Power Systems with Improved Primary Frequency Regulation

    SciTech Connect

    Lian, Jianming; Marinovici, Laurentiu D.; Kalsi, Karanjit; Du, Pengwei; Elizondo, Marcelo A.

    2012-12-12

    The conventional distributed hierarchical control architecture for multi-area power systems is revisited. In this paper, a new distributed hierarchical control architecture is proposed. In the proposed architecture, pilot generators are selected in each area to be equipped with decentralized robust control as a supplementary to the conventional droop speed control. With the improved primary frequency control, the system frequency can be restored to the nominal value without the help of secondary frequency control, which reduces the burden of the automatic generation control for frequency restoration. Moreover, the low frequency inter-area electromechanical oscillations can also be effectively damped. The effectiveness of the proposed distributed hierarchical control architecture is validated through detailed simulations.

  7. Nonactive-Power-Related Ancillary Services provided by Distribute Energy Resources

    SciTech Connect

    Xu, Yan; Tolbert, Leon M; Rizy, D Tom; Kueck, John D

    2006-01-01

    The nonactive-power-related ancillary services provided by distributed energy (DE) resources are categorized by voltage regulation, reactive power compensation, power factor correction, voltage and/or current unbalance compensation, and harmonics compensation. An instantaneous nonactive power theory is adopted to control the DE system to provide these ancillary services. Three control schemes, including nonactive current compensation, power factor correction, and voltage regulation, are developed which can perform one or more of the ancillary services. The control schemes are implemented in a DE system in simulation and experiments. The simulation and the experimental results show that DE is feasible for providing nonactive-power-related ancillary services.

  8. Reactive nitrogen species in cellular signaling

    PubMed Central

    Adams, Levi; Franco, Maria C

    2015-01-01

    The transduction of cellular signals occurs through the modification of target molecules. Most of these modifications are transitory, thus the signal transduction pathways can be tightly regulated. Reactive nitrogen species are a group of compounds with different properties and reactivity. Some reactive nitrogen species are highly reactive and their interaction with macromolecules can lead to permanent modifications, which suggested they were lacking the specificity needed to participate in cell signaling events. However, the perception of reactive nitrogen species as oxidizers of macromolecules leading to general oxidative damage has recently evolved. The concept of redox signaling is now well established for a number of reactive oxygen and nitrogen species. In this context, the post-translational modifications introduced by reactive nitrogen species can be very specific and are active participants in signal transduction pathways. This review addresses the role of these oxidative modifications in the regulation of cell signaling events. PMID:25888647

  9. Dynamic power flow controllers

    DOEpatents

    Divan, Deepakraj M.; Prasai, Anish

    2017-03-07

    Dynamic power flow controllers are provided. A dynamic power flow controller may comprise a transformer and a power converter. The power converter is subject to low voltage stresses and not floated at line voltage. In addition, the power converter is rated at a fraction of the total power controlled. A dynamic power flow controller controls both the real and the reactive power flow between two AC sources having the same frequency. A dynamic power flow controller inserts a voltage with controllable magnitude and phase between two AC sources; thereby effecting control of active and reactive power flows between two AC sources.

  10. Nebivolol prevents ethanol-induced reactive oxygen species generation and lipoperoxidation in the rat kidney by regulating NADPH oxidase activation and expression.

    PubMed

    do Vale, Gabriel T; Gonzaga, Natália A; Simplicio, Janaina A; Tirapelli, Carlos R

    2017-03-15

    We studied whether the β1-adrenergic antagonist nebivolol would prevent ethanol-induced reactive oxygen species generation and lipoperoxidation in the rat renal cortex. Male Wistar rats were treated with ethanol (20% v/v) for 2 weeks. Nebivolol (10mg/kg/day; p.o. gavage) prevented both the increase in superoxide anion (O2(-)) generation and thiobarbituric acid reactive substances (TBARS) concentration induced by ethanol in the renal cortex. Ethanol decreased nitrate/nitrite (NOx) concentration in the renal cortex, and nebivolol prevented this response. Nebivolol did not affect the reduction of hydrogen peroxide (H2O2) concentration induced by ethanol. Nebivolol prevented the ethanol-induced increase of catalase (CAT) activity. Both SOD activity and the levels of reduced glutathione (GSH) were not affected by treatment with nebivolol or ethanol. Neither ethanol nor nebivolol affected the expression of Nox1, Nox4, eNOS, nNOS, CAT, Nox organizer 1 (Noxo1), c-Src, p47(phox) or superoxide dismutase (SOD) isoforms in the renal cortex. On the other hand, treatment with ethanol increased Nox2 expression, and nebivolol prevented this response. Finally, nebivolol reduced the expression of protein kinase (PK) Cδ and Rac1. The major finding of our study is that nebivolol prevented ethanol-induced reactive oxygen species generation and lipoperoxidation in the kidney by a mechanism that involves reduction on the expression of Nox2, a catalytic subunit of NADPH oxidase. Additionally, we demonstrated that nebivolol reduces NADPH oxidase-derived reactive oxygen species by decreasing the expression of PKCδ and Rac1, which are important activators of NADPH oxidase.

  11. Engine combustion control via fuel reactivity stratification

    DOEpatents

    Reitz, Rolf Deneys; Hanson, Reed M.; Splitter, Derek A.; Kokjohn, Sage L.

    2016-06-28

    A compression ignition engine uses two or more fuel charges having two or more reactivities to control the timing and duration of combustion. In a preferred implementation, a lower-reactivity fuel charge is injected or otherwise introduced into the combustion chamber, preferably sufficiently early that it becomes at least substantially homogeneously dispersed within the chamber before a subsequent injection is made. One or more subsequent injections of higher-reactivity fuel charges are then made, and these preferably distribute the higher-reactivity matter within the lower-reactivity chamber space such that combustion begins in the higher-reactivity regions, and with the lower-reactivity regions following thereafter. By appropriately choosing the reactivities of the charges, their relative amounts, and their timing, combustion can be tailored to achieve optimal power output (and thus fuel efficiency), at controlled temperatures (and thus controlled NOx), and with controlled equivalence ratios (and thus controlled soot).

  12. Engine combustion control via fuel reactivity stratification

    DOEpatents

    Reitz, Rolf Deneys; Hanson, Reed M; Splitter, Derek A; Kokjohn, Sage L

    2013-12-31

    A compression ignition engine uses two or more fuel charges having two or more reactivities to control the timing and duration of combustion. In a preferred implementation, a lower-reactivity fuel charge is injected or otherwise introduced into the combustion chamber, preferably sufficiently early that it becomes at least substantially homogeneously dispersed within the chamber before a subsequent injection is made. One or more subsequent injections of higher-reactivity fuel charges are then made, and these preferably distribute the higher-reactivity matter within the lower-reactivity chamber space such that combustion begins in the higher-reactivity regions, and with the lower-reactivity regions following thereafter. By appropriately choose the reactivities of the charges, their relative amounts, and their timing, combustion can be tailored to achieve optimal power output (and thus fuel efficiency), at controlled temperatures (and thus controlled NOx), and with controlled equivalence ratios (and thus controlled soot).

  13. Engine combustion control via fuel reactivity stratification

    DOEpatents

    Reitz, Rolf Deneys; Hanson, Reed M.; Splitter, Derek A.; Kokjohn, Sage L.

    2015-07-14

    A compression ignition engine uses two or more fuel charges having two or more reactivities to control the timing and duration of combustion. In a preferred implementation, a lower-reactivity fuel charge is injected or otherwise introduced into the combustion chamber, preferably sufficiently early that it becomes at least substantially homogeneously dispersed within the chamber before a subsequent injection is made. One or more subsequent injections of higher-reactivity fuel charges are then made, and these preferably distribute the higher-reactivity matter within the lower-reactivity chamber space such that combustion begins in the higher-reactivity regions, and with the lower-reactivity regions following thereafter. By appropriately choosing the reactivities of the charges, their relative amounts, and their timing, combustion can be tailored to achieve optimal power output (and thus fuel efficiency), at controlled temperatures (and thus controlled NOx), and with controlled equivalence ratios (and thus controlled soot).

  14. What Is Reactive Arthritis?

    MedlinePlus

    ... Arthritis PDF Version Size: 69 KB November 2014 What is Reactive Arthritis? Fast Facts: An Easy-to- ... Information About Reactive Arthritis and Other Related Conditions What Causes Reactive Arthritis? Sometimes, reactive arthritis is set ...

  15. Emerging molecular mechanisms that power and regulate the anastral mitotic spindle of flowering plants.

    PubMed

    Bannigan, Alex; Lizotte-Waniewski, Michelle; Riley, Margaret; Baskin, Tobias I

    2008-01-01

    Flowering plants, lacking centrosomes as well as dynein, assemble their mitotic spindle via a pathway that is distinct visually and molecularly from that of animals and yeast. The molecular components underlying mitotic spindle assembly and function in plants are beginning to be discovered. Here, we review recent evidence suggesting the preprophase band in plants functions analogously to the centrosome in animals in establishing spindle bipolarity, and we review recent progress characterizing the roles of specific motor proteins in plant mitosis. Loss of function of certain minus-end-directed KIN-14 motor proteins causes a broadening of the spindle pole; whereas, loss of function of a KIN-5 causes the formation of monopolar spindles, resembling those formed when the homologous motor protein (e.g., Eg5) is knocked out in animal cells. We present a phylogeny of the kinesin-5 motor domain, which shows deep divergence among plant sequences, highlighting possibilities for specialization. Finally, we review information concerning the roles of selected structural proteins at mitosis as well as recent findings concerning regulation of M-phase in plants. Insight into the mitotic spindle will be obtained through continued comparison of mitotic mechanisms in a diversity of cells.

  16. Power training and postmenopausal hormone therapy affect transcriptional control of specific co-regulated gene clusters in skeletal muscle

    PubMed Central

    Fey, Vidal; Törmäkangas, Timo; Ronkainen, Paula H. A.; Taaffe, Dennis R.; Takala, Timo; Koskinen, Satu; Cheng, Sulin; Puolakka, Jukka; Kujala, Urho M.; Suominen, Harri; Sipilä, Sarianna; Kovanen, Vuokko

    2010-01-01

    At the moment, there is no clear molecular explanation for the steeper decline in muscle performance after menopause or the mechanisms of counteractive treatments. The goal of this genome-wide study was to identify the genes and gene clusters through which power training (PT) comprising jumping activities or estrogen containing hormone replacement therapy (HRT) may affect skeletal muscle properties after menopause. We used musculus vastus lateralis samples from early stage postmenopausal (50–57 years old) women participating in a yearlong randomized double-blind placebo-controlled trial with PT and HRT interventions. Using microarray platform with over 24,000 probes, we identified 665 differentially expressed genes. The hierarchical clustering method was used to assort the genes. Additionally, enrichment analysis of gene ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways was carried out to clarify whether assorted gene clusters are enriched with particular functional categories. The analysis revealed transcriptional regulation of 49 GO/KEGG categories. PT upregulated transcription in “response to contraction”—category revealing novel candidate genes for contraction-related regulation of muscle function while HRT upregulated gene expression related to functionality of mitochondria. Moreover, several functional categories tightly related to muscle energy metabolism, development, and function were affected regardless of the treatment. Our results emphasize that during the early stages of the postmenopause, muscle properties are under transcriptional modulation, which both PT and HRT partially counteract leading to preservation of muscle power and potentially reducing the risk for aging-related muscle weakness. More specifically, PT and HRT may function through improving energy metabolism, response to contraction as well as by preserving functionality of the mitochondria. Electronic supplementary material The online version of this

  17. Niobium sputtered Havar foils for the high-power production of reactive [18F]fluoride by proton irradiation of [18O]H2O targets.

    PubMed

    Wilson, J S; Avila-Rodriguez, M A; Johnson, R R; Zyuzin, A; McQuarrie, S A

    2008-05-01

    Niobium sputtered Havar entrance foils were used for the production of reactive [(18)F]fluoride by proton irradiation of [(18)O]H(2)O targets under pressurized conditions. The synthesis yield in the routine production of 2-[(18)F]fluoro-2-deoxy-glucose (FDG) was used as an indicative parameter of the reactivity of (18)F. The yield of FDG obtained with (18)F produced in a target with Havar foil was used as a baseline. No statistically significant difference was found in the saturated yields of (18)F when using Havar or Havar-Nb sputtered entrance foils. However, the amount of long-lived radionuclidic impurities decreased more than 10-fold using the Havar-Nb entrance foil. The average decay corrected synthesis yield of FDG, evaluated over a period of more than 2 years, was found to be approximately 5% higher when using a Havar-Nb entrance foil and a marked improvement on the FDG yield consistency was noted. In addition, the frequency of target rebuilding was greatly diminished when using the Nb sputtered entrance foil.

  18. The role of pulse length in target poisoning during reactive HiPIMS: application to amorphous HfO2

    NASA Astrophysics Data System (ADS)

    Ganesan, R.; Murdoch, B. J.; Treverrow, B.; Ross, A. E.; Falconer, I. S.; Kondyurin, A.; McCulloch, D. G.; Partridge, J. G.; McKenzie, D. R.; Bilek, M. M. M.

    2015-06-01

    In conventional reactive magnetron sputtering, target poisoning frequently leads to an instability that requires the reactive gas flow rate to be actively regulated to maintain a constant composition of the deposited layers. Here we demonstrate that the pulse length in high power impulse magnetron sputtering (HiPIMS) is important for determining the surface conditions on the target that lead to poisoning. By increasing the pulse length, a smooth transition can be achieved from a poisoned target condition (short pulses) to a quasi-metallic target condition (long pulses). Appropriate selection of pulse length eliminates the need for active regulation, enabling stable reactive magnetron sputter deposition of stoichiometric amorphous hafnium oxide (HfO2) from a Hf target. A model is presented for the reactive HiPIMS process in which the target operates in a partially poisoned mode with a distribution of oxide on its surface that depends on the pulse length.

  19. Improving Advanced Inverter Control Convergence in Distribution Power Flow

    SciTech Connect

    Nagarajan, Adarsh; Palmintier, Bryan; Ding, Fei; Mather, Barry; Baggu, Murali

    2016-11-21

    Simulation of modern distribution system powerflow increasingly requires capturing the impact of advanced PV inverter voltage regulation on powerflow. With Volt/var control, the inverter adjusts its reactive power flow as a function of the point of common coupling (PCC) voltage. Similarly, Volt/watt control curtails active power production as a function of PCC voltage. However, with larger systems and higher penetrations of PV, this active/reactive power flow itself can cause significant changes to the PCC voltage potentially introducing oscillations that slow the convergence of system simulations. Improper treatment of these advanced inverter functions could potentially lead to incorrect results. This paper explores a simple approach to speed such convergence by blending in the previous iteration's reactive power estimate to dampen these oscillations. Results with a single large (5MW) PV system and with multiple 500kW advanced inverters show dramatic improvements using this approach.

  20. Reactivity change in a fast-spectrum space power reactor due to a 328-meter-per-second (1075-ft/sec) impact

    NASA Technical Reports Server (NTRS)

    Peoples, J. A., Jr.; Puthoff, R. L.

    1973-01-01

    Application of nuclear reactors in space will present operational problems. One such problem is the possibility of an earth impact at velocities in excess of 305 m/sec (1000 ft/sec). This report shows the results of an impact against concrete at 328 m/sec (1075 ft/sec) and examines the deformed core to estimate the range of activity inserted as a result of the impact. The results of this examination are that the deformation of the reactor core within the containment vessel left only an estimated 2.7 percent void in the core and that the reactivity inserted due to this impact deformation could be from 4.0 to 10.25 dollars.

  1. Establishment of HSV1 Latency in Immunodeficient Mice Facilitates Efficient In Vivo Reactivation

    PubMed Central

    Ramakrishna, Chandran; Ferraioli, Adrianna; Calle, Aleth; Nguyen, Thanh K.; Openshaw, Harry; Lundberg, Patric S.; Lomonte, Patrick; Cantin, Edouard M.

    2015-01-01

    The establishment of latent infections in sensory neurons is a remarkably effective immune evasion strategy that accounts for the widespread dissemination of life long Herpes Simplex Virus type 1 (HSV1) infections in humans. Periodic reactivation of latent virus results in asymptomatic shedding and transmission of HSV1 or recurrent disease that is usually mild but can be severe. An in-depth understanding of the mechanisms regulating the maintenance of latency and reactivation are essential for developing new approaches to block reactivation. However, the lack of a reliable mouse model that supports efficient in vivo reactivation (IVR) resulting in production of infectious HSV1 and/or disease has hampered progress. Since HSV1 reactivation is enhanced in immunosuppressed hosts, we exploited the antiviral and immunomodulatory activities of IVIG (intravenous immunoglobulins) to promote survival of latently infected immunodeficient Rag mice. Latently infected Rag mice derived by high dose (HD), but not low dose (LD), HSV1 inoculation exhibited spontaneous reactivation. Following hyperthermia stress (HS), the majority of HD inoculated mice developed HSV1 encephalitis (HSE) rapidly and synchronously, whereas for LD inoculated mice reactivated HSV1 persisted only transiently in trigeminal ganglia (Tg). T cells, but not B cells, were required to suppress spontaneous reactivation in HD inoculated latently infected mice. Transfer of HSV1 memory but not OVA specific or naïve T cells prior to HS blocked IVR, revealing the utility of this powerful Rag latency model for studying immune mechanisms involved in control of reactivation. Crossing Rag mice to various knockout strains and infecting them with wild type or mutant HSV1 strains is expected to provide novel insights into the role of specific cellular and viral genes in reactivation, thereby facilitating identification of new targets with the potential to block reactivation. PMID:25760441

  2. Establishment of HSV1 latency in immunodeficient mice facilitates efficient in vivo reactivation.

    PubMed

    Ramakrishna, Chandran; Ferraioli, Adrianna; Calle, Aleth; Nguyen, Thanh K; Openshaw, Harry; Lundberg, Patric S; Lomonte, Patrick; Cantin, Edouard M

    2015-03-01

    The establishment of latent infections in sensory neurons is a remarkably effective immune evasion strategy that accounts for the widespread dissemination of life long Herpes Simplex Virus type 1 (HSV1) infections in humans. Periodic reactivation of latent virus results in asymptomatic shedding and transmission of HSV1 or recurrent disease that is usually mild but can be severe. An in-depth understanding of the mechanisms regulating the maintenance of latency and reactivation are essential for developing new approaches to block reactivation. However, the lack of a reliable mouse model that supports efficient in vivo reactivation (IVR) resulting in production of infectious HSV1 and/or disease has hampered progress. Since HSV1 reactivation is enhanced in immunosuppressed hosts, we exploited the antiviral and immunomodulatory activities of IVIG (intravenous immunoglobulins) to promote survival of latently infected immunodeficient Rag mice. Latently infected Rag mice derived by high dose (HD), but not low dose (LD), HSV1 inoculation exhibited spontaneous reactivation. Following hyperthermia stress (HS), the majority of HD inoculated mice developed HSV1 encephalitis (HSE) rapidly and synchronously, whereas for LD inoculated mice reactivated HSV1 persisted only transiently in trigeminal ganglia (Tg). T cells, but not B cells, were required to suppress spontaneous reactivation in HD inoculated latently infected mice. Transfer of HSV1 memory but not OVA specific or naïve T cells prior to HS blocked IVR, revealing the utility of this powerful Rag latency model for studying immune mechanisms involved in control of reactivation. Crossing Rag mice to various knockout strains and infecting them with wild type or mutant HSV1 strains is expected to provide novel insights into the role of specific cellular and viral genes in reactivation, thereby facilitating identification of new targets with the potential to block reactivation.

  3. Strategic automation of emotion regulation.

    PubMed

    Gallo, Inge Schweiger; Keil, Andreas; McCulloch, Kathleen C; Rockstroh, Brigitte; Gollwitzer, Peter M

    2009-01-01

    As implementation intentions are a powerful self-regulation tool for thought and action (meta-analysis by P. M. Gollwitzer & P. Sheeran, 2006), the present studies were conducted to address their effectiveness in regulating emotional reactivity. Disgust- (Study 1) and fear- (Study 2) eliciting stimuli were viewed under 3 different self-regulation instructions: the goal intention to not get disgusted or frightened, respectively, this goal intention furnished with an implementation intention (i.e., an if-then plan), and a no-self-regulation control group. Only implementation-intention participants succeeded in reducing their disgust and fear reactions as compared to goal-intention and control participants. In Study 3, electrocortical correlates (using dense-array electroencephalography) revealed differential early visual activity in response to spider slides in ignore implementation-intention participants, as reflected in a smaller P1. Theoretical and applied implications of the present findings for emotion regulation via implementation intentions are discussed.

  4. Regulation of Adaptive NK Cells and CD8 T Cells by HLA-C Correlates with Allogeneic Hematopoietic Cell Transplantation and with Cytomegalovirus Reactivation.

    PubMed

    Horowitz, Amir; Guethlein, Lisbeth A; Nemat-Gorgani, Neda; Norman, Paul J; Cooley, Sarah; Miller, Jeffrey S; Parham, Peter

    2015-11-01

    Mass cytometry was used to investigate the effect of CMV reactivation on lymphocyte reconstitution in hematopoietic cell transplant patients. For eight transplant recipients (four CMV negative and four CMV positive), we studied PBMCs obtained 6 mo after unrelated donor hematopoietic cell transplantation (HCT). Forty cell-surface markers, distinguishing all major leukocyte populations in PBMC, were analyzed with mass cytometry. This group included 34 NK cell markers. Compared with healthy controls, transplant recipients had higher HLA-C expression on CD56(-)CD16(+) NK cells, B cells, CD33(bright) myeloid cells, and CD4CD8 T cells. The increase in HLA-C expression was greater for CMV-positive HCT recipients than for CMV negative recipients. Present in CMV-positive HCT recipients, but not in CMV-negative HCT recipients or controls, is a population of killer cell Ig-like receptor (KIR)-expressing CD8 T cells not previously described. These CD8 T cells coexpress CD56, CD57, and NKG2C. The HCT recipients also have a population of CD57(+)NKG2A(+) NK cells that preferentially express KIR2DL1. An inverse correlation was observed between the frequencies of CD57(+)NKG2C(+) NK cells and CD57(+)NKG2A(+) NK cells. Although CD57(+)NKG2A(+) NK cells are less abundant in CMV-positive recipients, their phenotype is of a more activated cell than the CD57(+)NKG2A(+) NK cells of controls and CMV-negative HCT recipients. These data demonstrate that HCT and CMV reactivation are associated with an increased expression of HLA-C. This could influence NK cell education during lymphocyte reconstitution. The increased inhibitory KIR expression by proliferating CMV-specific CD8 T cells suggests regulatory interactions between HLA-C and KIR might promote Graft-versus-Leukemia effects following transplantation.

  5. Comparative study of reference currents and DC bus voltage control for Three-Phase Four-Wire Four-Leg SAPF to compensate harmonics and reactive power with 3D SVM.

    PubMed

    Chebabhi, A; Fellah, M K; Kessal, A; Benkhoris, M F

    2015-07-01

    In this paper the performances of three reference currents and DC bus voltage control techniques for Three-Phase Four-Wire Four-Leg SAPF are compared for balanced and unbalanced load conditions. The main goals are to minimize the harmonics, reduce the magnitude of neutral current, eliminate the zero-sequence current components caused by single-phase nonlinear loads and compensate the reactive power, and on the other hand improve performances such as robustness, stabilization, trajectory pursuit, and reduce time response. The three techniques are analyzed mathematically and simulation results are compared. The techniques considered for comparative study are the PI Control, Sliding Mode Control and the Backstepping Control. Synchronous reference frame theory (SRF) in the dqo-axes is used to generate the reference currents, of the inverter.

  6. Predictions of U.K. regulated power station contributions to regional air pollution and deposition: a model comparison exercise.

    PubMed

    Chemel, Charles; Sokhi, Ranjeet S; Dore, Anthony J; Sutton, Paul; Vincent, Keith J; Griffiths, Stephen J; Hayman, Garry D; Wright, Raymond D; Baggaley, Matthew; Hallsworth, Stephen; Prain, H Douglas; Fisher, Bernard E A

    2011-11-01

    Contributions of the emissions from a U.K. regulated fossil-fuel power station to regional air pollution and deposition are estimated using four air quality modeling systems for the year 2003. The modeling systems vary in complexity and emphasis in the way they treat atmospheric and chemical processes, and include the Community Multiscale Air Quality (CMAQ) modeling system in its versions 4.6 and 4.7, a nested modeling system that combines long- and short-range impacts (referred to as TRACK-ADMS [Trajectory Model with Atmospheric Chemical Kinetics-Atmospheric Dispersion Modelling System]), and the Fine Resolution Atmospheric Multi-pollutant Exchange (FRAME) model. An evaluation of the baseline calculations against U.K. monitoring network data is performed. The CMAQ modeling system version 4.6 data set is selected as the reference data set for the model footprint comparison. The annual mean air concentration and total deposition footprints are summarized for each modeling system. The footprints of the power station emissions can account for a significant fraction of the local impacts for some species (e.g., more than 50% for SO2 air concentration and non-sea-salt sulfur deposition close to the source) for 2003. The spatial correlation and the coefficient of variation of the root mean square error (CVRMSE) are calculated between each model footprint and that calculated by the CMAQ modeling system version 4.6. The correlation coefficient quantifies model agreement in terms of spatial patterns, and the CVRMSE measures the magnitude of the difference between model footprints. Possible reasons for the differences between model results are discussed. Finally, implications and recommendations for the regulatory assessment of the impact of major industrial sources using regional air quality modeling systems are discussed in the light of results from this case study.

  7. The antioxidative power AP—A new quantitative time dependent (2D) parameter for the determination of the antioxidant capacity and reactivity of different plants

    NASA Astrophysics Data System (ADS)

    Jung, Katinka; Richter, J.; Kabrodt, K.; Lücke, I. M.; Schellenberg, I.; Herrling, Th.

    2006-03-01

    In the last decade, naturally occurring antioxidants continue to play an important role in the food-supplement industry. The content of antioxidants in a plant depends on the species, temperature, humidity, period of growth, harvest month, part of the plant used and many other variables. Herein, we present a new method able to determine the all over antioxidative power (AP) of plant extracts or lyophilised plant parts based on the reducing activity against a stable test radical. The method is performed by ESR spectroscopy and is based on the well-known 1,1-diphenyl-2-picryl-hydrazil (DPPH) method with the major difference that both the antioxidative capacity and the antioxidative activity are used to characterise an antioxidant. The resulting antioxidative power is expressed in antioxidative units (AU), where 1 AU corresponds to the activity of a 1 ppm solution of Vitamin C as a benchmark. This method allows a rapid, unexpensive and general applicable technique for the measurement of the antioxidative power of very different kinds of substances. The inclusion of the kinetic behaviour of the reducing process of the antioxidant for the determination of the AP allows the identification of the main antioxidant present in a sample. Herein, we present the application example of seeds, sprouts and adult parts of dandelion, amaranth, quinoa, fenugreek, broccoli, red clover and mugwort, where the AP method permits to characterise the plants with the highest antioxidant capacity and reaction velocity. The method permits to select active plant extracts for the food and nutrition industry.

  8. The 'reactive

    NASA Astrophysics Data System (ADS)

    Battista Piccardo, Giovanni; Guarnieri, Luisa

    2010-05-01

    The Ligurian ophiolitic peridotites [South Lanzo, Erro-Tobbio, Internal Ligurides and Corsica] are characterized by the abundance of spinel(Sp) peridotites showing depleted compositions and ranging from Cpx-poor Sp lherzolites to Sp harzburgites. They were recognized in the last decades as refractory residua by MORB-forming partial melting of the asthenosphere, and were similar to abyssal peridotites. Recent structural and compositional studies promoted a better understanding of their structural and compositional features and their genetic processes. In the field these depleted peridotites replace with primary contacts pyroxenite-bearing fertile Sp lherzolites that have been recognized as sub-continental lithospheric mantle. Field relationships evidence that decametric-hectometric bodies of pristine pyroxenite-veined lithospheric Sp lherzolites are preserved as structural remnants within the km-scale masses of depleted peridotites. The depleted peridotites show coarse-grained recrystallized textures and reaction micro-structures indicating pyroxene dissolution and olivine precipitation that have been considered as records of melt/peridotite interaction during reactive diffuse porous flow of undersaturated melts. They show, moreover, contrasting bulk and mineral chemistries that cannot be produced by simple partial melting and melt extraction. In particular, their bulk compositions are depleted in SiO2 and enriched in FeO with respect to refractory residua after any kind of partial melting, as calculated by Niu (1997), indicating that they cannot be formed by simple partial melting and melt extraction processes. Moreover, TiO2 content in Sp is usually significantly higher (up to 0.8-1.0 wt%) than typical TiO2 contents of spinels (usually < 0.1-0.2 wt %) in fertile mantle peridotites and melting refractory residua, indicating that spinel attained element equilibration with a Ti-bearing basaltic melt. The depleted peridotites usually show strongly variable Cpx modal

  9. Design & development fo a 20-MW flywheel-based frequency regulation power plant : a study for the DOE Energy Storage Systems program.

    SciTech Connect

    Rounds, Robert; Peek, Georgianne Huff

    2009-01-01

    This report describes the successful efforts of Beacon Power to design and develop a 20-MW frequency regulation power plant based solely on flywheels. Beacon's Smart Matrix (Flywheel) Systems regulation power plant, unlike coal or natural gas generators, will not burn fossil fuel or directly produce particulates or other air emissions and will have the ability to ramp up or down in a matter of seconds. The report describes how data from the scaled Beacon system, deployed in California and New York, proved that the flywheel-based systems provided faster responding regulation services in terms of cost-performance and environmental impact. Included in the report is a description of Beacon's design package for a generic, multi-MW flywheel-based regulation power plant that allows accurate bids from a design/build contractor and Beacon's recommendations for site requirements that would ensure the fastest possible construction. The paper concludes with a statement about Beacon's plans for a lower cost, modular-style substation based on the 20-MW design.

  10. Voltage Regulation Using a Permanent Magnet Synchronous Generator with a Series Compensator: Preprint

    SciTech Connect

    Hsu, Ping; Wu, Ziping; Muljadi, Eduard; Gao, Wenzhong

    2015-08-24

    A wind power plant (WPP) is often operated at unity power factor, and the utility host where the WPP connects prefers to regulate the voltage. Although this may not be an issue in a stiff grid, the connection to a weak grid can be a problematic. This paper explores the advantages of having voltage regulation capability via reactive power control. Another issue in wind power generation is that not all turbines are able to control their reactive power due to technical reasons or contractual obligations. A synchronous condenser (SC) using a permanent magnet synchronous generator (PMSG) is proposed to provide necessary reactive power for regulating voltage at a weak grid connection. A PMSG has the advantage of higher efficiency and reliability. Because of its lack of a field winding, a PMSG is typically controlled by a full-power converter, which can be costly. In the proposed system, the reactive power of the SC is controlled by a serially connected compensator operating in a closed-loop configuration. The compensator also damps the PMSG’s tendency to oscillate. The compensator’s VA rating is only a fraction of the rating of the SC and the PMSG. In this initial investigation, the proposed scheme is shown to be effective by computer simulations.

  11. Low-power output-capacitorless low-dropout regulator with adjustable charge injection technique for on-off-keying transmitters

    NASA Astrophysics Data System (ADS)

    Akita, Ippei; Asai, Shochi; Ishida, Makoto

    2014-01-01

    In this paper a low-power low-dropout (LDO) regulator for p power amplifier (PA) in on-off-keying (OOK) transmitters is proposed. The proposed technique needs no external output capacitors, enabling small-area and low-cost implementation. The response of a rapid load change in an OOK transmitter is improved by the proposed adjustable charge injection (ACI) technique that uses timing information of a transmitted data signal. The designed regulator with the ACI technique has been fabricated in a standard 180 nm CMOS process and achieves 100 mVpp dropout voltage ripple. The measured current dissipation is 65 µA at a power supply of 1.8 V.

  12. An Arabidopsis Zinc Finger Protein Increases Abiotic Stress Tolerance by Regulating Sodium and Potassium Homeostasis, Reactive Oxygen Species Scavenging and Osmotic Potential

    PubMed Central

    Zang, Dandan; Li, Hongyan; Xu, Hongyun; Zhang, Wenhui; Zhang, Yiming; Shi, Xinxin; Wang, Yucheng

    2016-01-01

    Plant zinc finger proteins (ZFPs) comprise a large protein family and they are mainly involved in abiotic stress tolerance. Although Arabidopsis RING/FYVE/PHD ZFP At5g62460 (AtRZFP) is found to bind to zinc, whether it is involved in abiotic stress tolerance is still unknown. In the present study, we characterized the roles of AtRZFP in response to abiotic stresses. The expression of AtRZFP was induced significantly by salt and osmotic stress. AtRZFP positively mediates tolerance to salt and osmotic stress. Additionally, compared with wild-type Arabidopsis plants, plants overexpressing AtRZFP showed reduced reactive oxygen species (ROSs) accumulation, enhanced superoxide dismutase and peroxidase activity, increased soluble sugars and proline contents, reduced K+ loss, decreased Na+ accumulation, stomatal aperture and the water loss rate. Conversely, AtRZFP knockout plants displayed the opposite physiological changes when exposed to salt or osmotic stress conditions. These data suggested that AtRZFP enhances salt and osmotic tolerance through a series of physiological processes, including enhanced ROSs scavenging, maintaining Na+ and K+ homeostasis, controlling the stomatal aperture to reduce the water loss rate, and accumulating soluble sugars and proline to adjust the osmotic potential. PMID:27605931

  13. [Response of reactive oxygen metabolism in melon chloroplasts to short-term salinity-alkalinity stress regulated by exogenous γ-aminobutyric acid].

    PubMed

    Xiang, Li-xia; Hu, Li-pan; Hu, Xiao-hui; Pan, Xiong-bo; Ren, Wen-qi

    2015-12-01

    The regulatory effect of exogenous γ-aminobutyric acid (GABA) on metabolism of reactive oxygen species (ROS) in melon chloroplasts under short-term salinity-alkalinity stress were investigated in melon variety 'Jinhui No. 1', which was cultured with deep flow hydroponics. The result showed that under salinity-alkalinity stress, the photosynthetic pigment content, MDA content, superoxide anion (O₂·) production rate and hydrogen peroxide (H₂O₂) content in chloroplast increased significantly, the contents of antioxidants ascorbic acid (AsA) and glutathione (GSH) increased, and the activities of H⁺-ATPase and H⁺-PPiase were inhibited obviously. With exogenous GABA application, the accumulations of O₂·, MDA and H₂O₂ induced by salinity-alkalinity stress were inhibited. Exogenous GABA alleviated the increase of photosynthetic pigment content, improved the activity of SOD, enzymes of AsA-GSH cycle, total AsA and total GSH while decreased the AsA/DHA ratio and GSH/GSSH ratio. Foliar GABA could enhance the H⁺-ATPase and H⁺-PPiase activities. Our results suggested that the exogenous GABA could accelerate the ROS metabolism in chloroplast, promote the recycle of AsA-GSH, and maintain the permeability of cell membrane to improve the ability of melon chloroplast against salinity-alkalinity stress.

  14. CbRCI35, a Cold Responsive Peroxidase from Capsella bursa-pastoris Regulates Reactive Oxygen Species Homeostasis and Enhances Cold Tolerance in Tobacco.

    PubMed

    Zhou, Mingqi; Li, Weiwei; Zheng, Ye; Lin, Ping; Yao, Xiaohua; Lin, Juan

    2016-01-01

    Low temperature affects gene regulatory networks and alters cellular metabolism to inhibit plant growth. Peroxidases are widely distributed in plants and play a large role in adjusting and controlling reactive oxygen species (ROS) homeostasis in response to abiotic stresses such as low temperature. The Rare Cold-Inducible 35 gene from Capsella bursa-pastoris (CbRCI35) belongs to the type III peroxidase family and has been reported to be a cold responsive gene in plants. Here we performed an expressional characterization of CbRCI35 under cold and ionic liquid treatments. The promoter of CbRCI35 was also cloned and its activity was examined using the GUS reporter system. CbRCI35 protein was localized in the cytoplasm according to sequence prediction and GFP fusion assay. Heterologous expression tests revealed that CbRCI35 conferred enhanced resistance to low temperature and activated endogenous cold responsive signaling in tobacco. Furthermore, in the normal condition the ROS accumulation was moderately enhanced while after chilling exposure superoxide dismutase activity was increased in CbRCI53 transgenic plants. The ROS metabolism related genes expression was altered accordingly. We conclude that CbRCI35 modulates ROS homeostasis and contributes to cold tolerance in plants.

  15. Fucoidan induces Toll-like receptor 4-regulated reactive oxygen species and promotes endoplasmic reticulum stress-mediated apoptosis in lung cancer

    PubMed Central

    Hsu, Hsien-Yeh; Lin, Tung-Yi; Lu, Mei-Kuang; Leng, Pei-Ju; Tsao, Shu-Ming; Wu, Yu-Chung

    2017-01-01

    Fucoidan, a sulfated polysaccharide extracted from brown algae, exhibits anti-cancer activity. However, the effects and mechanism of fucoidan-induced apoptosis via endoplasmic reticulum (ER) stress is unclear. In this study, we demonstrated that fucoidan prevents tumorigenesis and reduces tumor size in LLC1-xenograft male C57BL/6 mice. Fucoidan induces an ER stress response by activating the PERK-ATF4-CHOP pathway, resulting in apoptotic cell death in vitro and in vivo. Furthermore, ATF4 knockdown abolishes fucoidan-induced CHOP expression and rescues cell viability. Specifically, fucoidan increases intracellular reactive oxygen species (ROS), which increase ATF4 and CHOP in lung cancer cells. Using the ROS scavenger N-acetyl-l-cysteine (NAC), we found that ROS generation is involved in fucoidan-induced ER stress-mediated apoptosis. Moreover, via Toll-like receptor 4 (TLR4) knockdown, we demonstrated that fucoidan-induced ROS and CHOP expression were attenuated. Our study is the first to identify a novel mechanism for the antitumor activity of fucoidan. We showed that fucoidan inhibits tumor viability by activating the TLR4/ROS/ER stress axis and the downstream PERK-ATF4-CHOP pathway, leading to apoptosis and suppression of lung cancer cell progression. Together, these results indicate that fucoidan is a potential preventive and therapeutic agent for lung cancer that acts via activation of ROS-dependent ER stress pathways. PMID:28332554

  16. Salt-responsive ERF1 regulates reactive oxygen species-dependent signaling during the initial response to salt stress in rice.

    PubMed

    Schmidt, Romy; Mieulet, Delphine; Hubberten, Hans-Michael; Obata, Toshihiro; Hoefgen, Rainer; Fernie, Alisdair R; Fisahn, Joachim; San Segundo, Blanca; Guiderdoni, Emmanuel; Schippers, Jos H M; Mueller-Roeber, Bernd

    2013-06-01

    Early detection of salt stress is vital for plant survival and growth. Still, the molecular processes controlling early salt stress perception and signaling are not fully understood. Here, we identified salt-responsive ERF1 (SERF1), a rice (Oryza sativa) transcription factor (TF) gene that shows a root-specific induction upon salt and hydrogen peroxide (H2O2) treatment. Loss of SERF1 impairs the salt-inducible expression of genes encoding members of a mitogen-activated protein kinase (MAPK) cascade and salt tolerance-mediating TFs. Furthermore, we show that SERF1-dependent genes are H2O2 responsive and demonstrate that SERF1 binds to the promoters of MAPK kinase kinase6 (MAP3K6), MAPK5, dehydration-responsive element bindinG2A (DREB2A), and zinc finger protein179 (ZFP179) in vitro and in vivo. SERF1 also directly induces its own gene expression. In addition, SERF1 is a phosphorylation target of MAPK5, resulting in enhanced transcriptional activity of SERF1 toward its direct target genes. In agreement, plants deficient for SERF1 are more sensitive to salt stress compared with the wild type, while constitutive overexpression of SERF1 improves salinity tolerance. We propose that SERF1 amplifies the reactive oxygen species-activated MAPK cascade signal during the initial phase of salt stress and translates the salt-induced signal into an appropriate expressional response resulting in salt tolerance.

  17. CbRCI35, a Cold Responsive Peroxidase from Capsella bursa-pastoris Regulates Reactive Oxygen Species Homeostasis and Enhances Cold Tolerance in Tobacco

    PubMed Central

    Zhou, Mingqi; Li, Weiwei; Zheng, Ye; Lin, Ping; Yao, Xiaohua; Lin, Juan

    2016-01-01

    Low temperature affects gene regulatory networks and alters cellular metabolism to inhibit plant growth. Peroxidases are widely distributed in plants and play a large role in adjusting and controlling reactive oxygen species (ROS) homeostasis in response to abiotic stresses such as low temperature. The Rare Cold-Inducible 35 gene from Capsella bursa-pastoris (CbRCI35) belongs to the type III peroxidase family and has been reported to be a cold responsive gene in plants. Here we performed an expressional characterization of CbRCI35 under cold and ionic liquid treatments. The promoter of CbRCI35 was also cloned and its activity was examined using the GUS reporter system. CbRCI35 protein was localized in the cytoplasm according to sequence prediction and GFP fusion assay. Heterologous expression tests revealed that CbRCI35 conferred enhanced resistance to low temperature and activated endogenous cold responsive signaling in tobacco. Furthermore, in the normal condition the ROS accumulation was moderately enhanced while after chilling exposure superoxide dismutase activity was increased in CbRCI53 transgenic plants. The ROS metabolism related genes expression was altered accordingly. We conclude that CbRCI35 modulates ROS homeostasis and contributes to cold tolerance in plants. PMID:27818675

  18. Fucoidan induces Toll-like receptor 4-regulated reactive oxygen species and promotes endoplasmic reticulum stress-mediated apoptosis in lung cancer.

    PubMed

    Hsu, Hsien-Yeh; Lin, Tung-Yi; Lu, Mei-Kuang; Leng, Pei-Ju; Tsao, Shu-Ming; Wu, Yu-Chung

    2017-03-23

    Fucoidan, a sulfated polysaccharide extracted from brown algae, exhibits anti-cancer activity. However, the effects and mechanism of fucoidan-induced apoptosis via endoplasmic reticulum (ER) stress is unclear. In this study, we demonstrated that fucoidan prevents tumorigenesis and reduces tumor size in LLC1-xenograft male C57BL/6 mice. Fucoidan induces an ER stress response by activating the PERK-ATF4-CHOP pathway, resulting in apoptotic cell death in vitro and in vivo. Furthermore, ATF4 knockdown abolishes fucoidan-induced CHOP expression and rescues cell viability. Specifically, fucoidan increases intracellular reactive oxygen species (ROS), which increase ATF4 and CHOP in lung cancer cells. Using the ROS scavenger N-acetyl-l-cysteine (NAC), we found that ROS generation is involved in fucoidan-induced ER stress-mediated apoptosis. Moreover, via Toll-like receptor 4 (TLR4) knockdown, we demonstrated that fucoidan-induced ROS and CHOP expression were attenuated. Our study is the first to identify a novel mechanism for the antitumor activity of fucoidan. We showed that fucoidan inhibits tumor viability by activating the TLR4/ROS/ER stress axis and the downstream PERK-ATF4-CHOP pathway, leading to apoptosis and suppression of lung cancer cell progression. Together, these results indicate that fucoidan is a potential preventive and therapeutic agent for lung cancer that acts via activation of ROS-dependent ER stress pathways.

  19. Reactive oxygen species production in cardiac mitochondria after complex I inhibition: Modulation by substrate-dependent regulation of the NADH/NAD(+) ratio.

    PubMed

    Korge, Paavo; Calmettes, Guillaume; Weiss, James N

    2016-07-01

    Reactive oxygen species (ROS) production by isolated complex I is steeply dependent on the NADH/NAD(+) ratio. We used alamethicin-permeabilized mitochondria to study the substrate-dependence of matrix NADH and ROS production when complex I is inhibited by piericidin or rotenone. When complex I was inhibited in the presence of malate/glutamate, membrane permeabilization accelerated O2 consumption and ROS production due to a rapid increase in NADH generation that was not limited by matrix NAD(H) efflux. In the presence of inhibitor, both malate and glutamate were required to generate a high enough NADH/NAD(+) ratio to support ROS production through the coordinated activity of malate dehydrogenase (MDH) and aspartate aminotransferase (AST). With malate and glutamate present, the rate of ROS production was closely related to local NADH generation, whereas in the absence of substrates, ROS production was accelerated by increase in added [NADH]. With malate alone, oxaloacetate accumulation limited NADH production by MDH unless glutamate was also added to promote oxaloacetate removal via AST. α-ketoglutarate (KG) as well as AST inhibition also reversed NADH generation and inhibited ROS production. If malate and glutamate were provided before rather than after piericidin or rotenone, ROS generation was markedly reduced due to time-dependent efflux of CoA. CoA depletion decreased KG oxidation by α-ketoglutarate dehydrogenase (KGDH), such that the resulting increase in [KG] inhibited oxaloacetate removal by AST and NADH generation by MDH. These findings were largely obscured in intact mitochondria due to robust H2O2 scavenging and limited ability to control substrate concentrations in the matrix. We conclude that in mitochondria with inhibited complex I, malate/glutamate-stimulated ROS generation depends strongly on oxaloacetate removal and on the ability of KGDH to oxidize KG generated by AST.

  20. Differential Regulation of Self-reactive CD4+ T Cells in Cervical Lymph Nodes and Central Nervous System during Viral Encephalomyelitis

    PubMed Central

    Savarin, Carine; Bergmann, Cornelia C.; Hinton, David R.; Stohlman, Stephen A.

    2016-01-01

    Viral infections have long been implicated as triggers of autoimmune diseases, including multiple sclerosis (MS), a central nervous system (CNS) inflammatory demyelinating disorder. Epitope spreading, molecular mimicry, cryptic antigen, and bystander activation have been implicated as mechanisms responsible for activating self-reactive (SR) immune cells, ultimately leading to organ-specific autoimmune disease. Taking advantage of coronavirus JHM strain of mouse hepatitis virus (JHMV)-induced demyelination, this study demonstrates that the host also mounts counteractive measures to specifically limit expansion of endogenous SR T cells. In this model, immune-mediated demyelination is associated with induction of SR T cells after viral control. However, their decline during persisting infection, despite ongoing demyelination, suggests an active control mechanism. Antigen-specific IL-10-secreting CD4+ T cells (Tr1) and Foxp3+ regulatory T cells (Tregs), both known to control autoimmunity and induced following JHMV infection, were assessed for their relative in vivo suppressive function of SR T cells. Ablation of Foxp3+ Tregs in chronically infected DEREG mice significantly increased SR CD4+ T cells within cervical lymph nodes (CLN), albeit without affecting their numbers or activation within the CNS compared to controls. In contrast, infected IL-27 receptor deficient (IL-27R−/−) mice, characterized by a drastic reduction of Tr1 cells, revealed that SR CD4+ T cells in CLN remained unchanged but were specifically increased within the CNS. These results suggest that distinct Treg subsets limit SR T cells in the draining lymph nodes and CNS to maximize suppression of SR T-cell-mediated autoimmune pathology. The JHMV model is thus valuable to decipher tissue-specific mechanisms preventing autoimmunity. PMID:27708643

  1. Differential Regulation of Self-reactive CD4(+) T Cells in Cervical Lymph Nodes and Central Nervous System during Viral Encephalomyelitis.

    PubMed

    Savarin, Carine; Bergmann, Cornelia C; Hinton, David R; Stohlman, Stephen A

    2016-01-01

    Viral infections have long been implicated as triggers of autoimmune diseases, including multiple sclerosis (MS), a central nervous system (CNS) inflammatory demyelinating disorder. Epitope spreading, molecular mimicry, cryptic antigen, and bystander activation have been implicated as mechanisms responsible for activating self-reactive (SR) immune cells, ultimately leading to organ-specific autoimmune disease. Taking advantage of coronavirus JHM strain of mouse hepatitis virus (JHMV)-induced demyelination, this study demonstrates that the host also mounts counteractive measures to specifically limit expansion of endogenous SR T cells. In this model, immune-mediated demyelination is associated with induction of SR T cells after viral control. However, their decline during persisting infection, despite ongoing demyelination, suggests an active control mechanism. Antigen-specific IL-10-secreting CD4(+) T cells (Tr1) and Foxp3(+) regulatory T cells (Tregs), both known to control autoimmunity and induced following JHMV infection, were assessed for their relative in vivo suppressive function of SR T cells. Ablation of Foxp3(+) Tregs in chronically infected DEREG mice significantly increased SR CD4(+) T cells within cervical lymph nodes (CLN), albeit without affecting their numbers or activation within the CNS compared to controls. In contrast, infected IL-27 receptor deficient (IL-27R(-/-)) mice, characterized by a drastic reduction of Tr1 cells, revealed that SR CD4(+) T cells in CLN remained unchanged but were specifically increased within the CNS. These results suggest that distinct Treg subsets limit SR T cells in the draining lymph nodes and CNS to maximize suppression of SR T-cell-mediated autoimmune pathology. The JHMV model is thus valuable to decipher tissue-specific mechanisms preventing autoimmunity.

  2. Abscisic acid-regulated responses of aba2-1 under osmotic stress: the abscisic acid-inducible antioxidant defence system and reactive oxygen species production.

    PubMed

    Ozfidan, C; Turkan, I; Sekmen, A H; Seckin, B

    2012-03-01

    We investigated the interaction among abscisic acid (ABA), reactive oxygen species (ROS) and antioxidant defence system in the transduction of osmotic stress signalling using Arabidopsis thaliana WT (Columbia ecotype, WT) and an ABA-deficient mutant (aba2-1). For this, 50 μm ABA and osmotic stress, induced with 40% (w/v) polyethylene glycol (PEG8000; -0.7 MPa), were applied to WT and aba2-1 for 6, 12 or 24 h. Time course analysis was undertaken for determination of total/isoenzyme activity of the antioxidant enzymes, superoxide dismutase (SOD; EC 1.15.1.1), catalase (CAT; EC 1.11.1.6), ascorbate peroxidase (APX; EC 1.11.1.11), NADPH oxidase (NOX; EC 1.6.3.1) activity; scavenging activity of the hydroxyl radical (OH˙), hydrogen peroxide (H(2) O(2) ); endogenous ABA and malondialdehyde (MDA). The highest H(2) O(2) and MDA content was found in PEG-treated groups of both genotypes, but with more in aba2-1. ABA treatment under stress reduced the accumulation of H(2) O(2) and MDA, while it promoted activity of SOD, CAT and APX. APX activity was higher than CAT activity in ABA-treated WT and aba2-1, indicating a protective role of APX rather than CAT during osmotic stress-induced oxidative damage. Treatment with ABA also significantly induced increased NOX activity. Oxidative damage was lower in ABA-treated seedlings of both genotypes, which was associated with greater activity of SOD (Mn-SOD1 and 2 and Fe-SOD isoenzymes), CAT and APX in these seedlings after 24 h of stress. These results suggest that osmotic stress effects were overcome by ABA treatment because of increased SOD, CAT, APX and NOX.

  3. Paclitaxel-resistant HeLa cells have up-regulated levels of reactive oxygen species and increased expression of taxol resistance gene 1.

    PubMed

    Bi, Wenxiang; Wang, Yuxia; Sun, Gaoying; Zhang, Xiaojin; Wei, Yongqing; Li, Lu; Wang, Xiaoyuan

    2014-07-01

    This study is to establish a paclitaxel (PTX)-resistant human cervical carcinoma HeLa cell line (HeLa/PTX) and to investigate its redox characteristics and the expression of taxol resistance gene 1 (Txr1). HeLa cells were treated with PTX and effects of PTX on cell proliferation were detected through cell counting and the MTT assay. Levels of cellular reactive oxygen species (ROS), reduced glutathione (GSH), and oxidized glutathione (GSSG) as well as the ratio of GSH to GSSG were measured by the 2,7-difluorescein diacetate (DCFH-DA) method and the 5,5'dithiobis(2-nitrobenzoic acid) (DTNB) method. Activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were determined by the nitrite formation method, the molybdate colorimetric method, and the DTNB colorimetric method, respectively. The level of Txr1 mRNA was determined by real-time PCR. Compared with the regular HeLa cells, HeLa/PTX cells were larger in size and had more cytoplasmic granules. The population doubling time for HeLa/PTX cells was 1.32 times of that of HeLa cells (P<0.01). HeLa/PTX cells showed stronger resistance to PTX than HeLa cells with a resistance index of 122.69. HeLa/PTX cells had higher levels of ROS (P<0.01) and Txr1 mRNA (P<0.01), lower level of GSH (P < 0.05), and lower activities of SOD (P<0.01) and GPx (P < 0.05) than HeLa cells. HeLa/PTX cells, with higher levels of ROS and Txr1 mRNA expression, are more resistant to PTX than HeLa cells.

  4. The Arabidopsis KINβγ Subunit of the SnRK1 Complex Regulates Pollen Hydration on the Stigma by Mediating the Level of Reactive Oxygen Species in Pollen.

    PubMed

    Gao, Xin-Qi; Liu, Chang Zhen; Li, Dan Dan; Zhao, Ting Ting; Li, Fei; Jia, Xiao Na; Zhao, Xin-Ying; Zhang, Xian Sheng

    2016-07-01

    Pollen-stigma interactions are essential for pollen germination. The highly regulated process of pollen germination includes pollen adhesion, hydration, and germination on the stigma. However, the internal signaling of pollen that regulates pollen-stigma interactions is poorly understood. KINβγ is a plant-specific subunit of the SNF1-related protein kinase 1 complex which plays important roles in the regulation of plant development. Here, we showed that KINβγ was a cytoplasm- and nucleus-localized protein in the vegetative cells of pollen grains in Arabidopsis. The pollen of the Arabidopsis kinβγ mutant could not germinate on stigma, although it germinated normally in vitro. Further analysis revealed the hydration of kinβγ mutant pollen on the stigma was compromised. However, adding water to the stigma promoted the germination of the mutant pollen in vivo, suggesting that the compromised hydration of the mutant pollen led to its defective germination. In kinβγ mutant pollen, the structure of the mitochondria and peroxisomes was destroyed, and their numbers were significantly reduced compared with those in the wild type. Furthermore, we found that the kinβγ mutant exhibited reduced levels of reactive oxygen species (ROS) in pollen. The addition of H2O2 in vitro partially compensated for the reduced water absorption of the mutant pollen, and reducing ROS levels in pollen by overexpressing Arabidopsis CATALASE 3 resulted in compromised hydration of pollen on the stigma. These results indicate that Arabidopsis KINβγ is critical for the regulation of ROS levels by mediating the biogenesis of mitochondria and peroxisomes in pollen, which is required for pollen-stigma interactions during pollination.

  5. A STRESS-RESPONSIVE NAC1-Regulated Protein Phosphatase Gene Rice Protein Phosphatase18 Modulates Drought and Oxidative Stress Tolerance through Abscisic Acid-Independent Reactive Oxygen Species Scavenging in Rice1[W][OPEN

    PubMed Central

    You, Jun; Zong, Wei; Hu, Honghong; Li, Xianghua; Xiao, Jinghua; Xiong, Lizhong

    2014-01-01

    Plants respond to abiotic stresses through a complexity of signaling pathways, and the dephosphorylation mediated by protein phosphatase (PP) is an important event in this process. We identified a rice (Oryza sativa) PP2C gene, OsPP18, as a STRESS-RESPONSIVE NAC1 (SNAC1)-regulated downstream gene. The ospp18 mutant was more sensitive than wild-type plants to drought stress at both the seedling and panicle development stages. Rice plants with OsPP18 suppressed through artificial microRNA were also hypersensitive to drought stress. Microarray analysis of the mutant revealed that genes encoding reactive oxygen species (ROS) scavenging enzymes were down-regulated in the ospp18 mutant, and the mutant exhibited reduced activities of ROS scavenging enzymes and increased sensitivity to oxidative stresses. Overexpression of OsPP18 in rice led to enhanced osmotic and oxidative stress tolerance. The expression of OsPP18 was induced by drought stress but not induced by abscisic acid (ABA). Although OsPP18 is a typical PP2C with enzymatic activity, it did not interact with SNF1-RELATED PROTEIN KINASE2 protein kinases, which function in ABA signaling. Meanwhile, the expression of ABA-responsive genes was not affected in the ospp18 mutant, and the ABA sensitivities of the ospp18 mutant and OsPP18-overexpressing plants were also not altered. Together, these findings suggest that OsPP18 is a unique PP2C gene that is regulated by SNAC1 and confers drought and oxidative stress tolerance by regulating ROS homeostasis through ABA-independent pathways. PMID:25318938

  6. The Arabidopsis KINβγ Subunit of the SnRK1 Complex Regulates Pollen Hydration on the Stigma by Mediating the Level of Reactive Oxygen Species in Pollen

    PubMed Central

    Zhao, Ting Ting; Li, Fei; Jia, Xiao Na; Zhao, Xin-Ying; Zhang, Xian Sheng

    2016-01-01

    Pollen–stigma interactions are essential for pollen germination. The highly regulated process of pollen germination includes pollen adhesion, hydration, and germination on the stigma. However, the internal signaling of pollen that regulates pollen–stigma interactions is poorly understood. KINβγ is a plant-specific subunit of the SNF1-related protein kinase 1 complex which plays important roles in the regulation of plant development. Here, we showed that KINβγ was a cytoplasm- and nucleus-localized protein in the vegetative cells of pollen grains in Arabidopsis. The pollen of the Arabidopsis kinβγ mutant could not germinate on stigma, although it germinated normally in vitro. Further analysis revealed the hydration of kinβγ mutant pollen on the stigma was compromised. However, adding water to the stigma promoted the germination of the mutant pollen in vivo, suggesting that the compromised hydration of the mutant pollen led to its defective germination. In kinβγ mutant pollen, the structure of the mitochondria and peroxisomes was destroyed, and their numbers were significantly reduced compared with those in the wild type. Furthermore, we found that the kinβγ mutant exhibited reduced levels of reactive oxygen species (ROS) in pollen. The addition of H2O2 in vitro partially compensated for the reduced water absorption of the mutant pollen, and reducing ROS levels in pollen by overexpressing Arabidopsis CATALASE 3 resulted in compromised hydration of pollen on the stigma. These results indicate that Arabidopsis KINβγ is critical for the regulation of ROS levels by mediating the biogenesis of mitochondria and peroxisomes in pollen, which is required for pollen–stigma interactions during pollination. PMID:27472382

  7. The 8.4 MW Modulator/Regulator Power Systems for the Electron Cyclotron Heating Facility Upgrade at DIII-D

    SciTech Connect

    S.G.E. Pronko; D.S. Baggest

    1999-12-01

    Over the next three years the DIII-D National Fusion Facility at General Atomics will upgrade its electron cyclotron heating (ECH) capability from the present 3 MW at 110 GHz to 10 MW of injected microwave power. There will be ten gyrotron tubes supplied by five 8.4 MW modulator/regulator (M/R) power systems. The project has gained considerable leverage from the acquisition of surplus hardware from the MFTF program that was conducted at LLNL in the early 1980s. One of these systems had been refurbished and converted for use as an ECH power supply earlier. The experience gained and the lessons learned from operating that system have proved valuable in guiding the engineering of the new systems. This paper provides an overview of the power system design and a report on the present status of the project.

  8. Regulator of G Protein Signaling 6 (RGS6) Mediates Doxorubicin-induced ATM and p53 Activation by a Reactive Oxygen Species (ROS)-dependent Mechanism

    PubMed Central

    Huang, Jie; Yang, Jianqi; Maity, Biswanath; Mayuzumi, Daisuke; Fisher, Rory A.

    2011-01-01

    Doxorubicin (DXR), among the most widely used cancer chemotherapy agents, promotes cancer cell death via activation of ATM and the resultant up-regulation of tumor suppressor p53. The exact mechanism by which DXR activates ATM is not fully understood. Here we discovered a novel role for Regulator of G protein Signaling 6 (RGS6) in mediating activation of ATM and p53 by DXR. RGS6 was robustly induced by DXR, and genetic loss of RGS6 dramatically impaired DXR-induced activation of ATM and p53, as well as its in vivo apoptotic actions in heart. The ability of RGS6 to promote p53 activation in response to DXR was independent of RGS6 interaction with G proteins but required ATM. RGS6 mediated activation of ATM and p53 by DXR via a ROS-dependent and DNA damage-independent mechanism. This mechanism represents the primary means by which DXR promotes activation of the ATM-p53-apoptosis pathway that underlies its cytotoxic activity. Our findings contradict the canonical theories that DXR activates ATM primarily by promoting DNA damage either directly or indirectly (via ROS) and that RGS6 function is mediated by its interactions with G proteins. These findings reveal a new mechanism for the chemotherapeutic actions of DXR and identify RGS6 as a novel target for cancer chemotherapy. PMID:21859827

  9. Deferasirox is a powerful NF-κB inhibitor in myelodysplastic cells and in leukemia cell lines acting independently from cell iron deprivation by chelation and reactive oxygen species scavenging

    PubMed Central

    Messa, Emanuela; Carturan, Sonia; Maffè, Chiara; Pautasso, Marisa; Bracco, Enrico; Roetto, Antonella; Messa, Francesca; Arruga, Francesca; Defilippi, Ilaria; Rosso, Valentina; Zanone, Chiara; Rotolo, Antonia; Greco, Elisabetta; Pellegrino, Rosa M.; Alberti, Daniele; Saglio, Giuseppe; Cilloni, Daniela

    2010-01-01

    Background Usefulness of iron chelation therapy in myelodysplastic patients is still under debate but many authors suggest its possible role in improving survival of low-risk myelodysplastic patients. Several reports have described an unexpected effect of iron chelators, such as an improvement in hemoglobin levels, in patients affected by myelodysplastic syndromes. Furthermore, the novel chelator deferasirox induces a similar improvement more rapidly. Nuclear factor-κB is a key regulator of many cellular processes and its impaired activity has been described in different myeloid malignancies including myelodysplastic syndromes. Design and Methods We evaluated deferasirox activity on nuclear factor-κB in myelodysplastic syndromes as a possible mechanism involved in hemoglobin improvement during in vivo treatment. Forty peripheral blood samples collected from myelodysplastic syndrome patients were incubated with 50 μM deferasirox for 18h. Results Nuclear factor-κB activity dramatically decreased in samples showing high basal activity as well as in cell lines, whereas no similar behavior was observed with other iron chelators despite a similar reduction in reactive oxygen species levels. Additionally, ferric hydroxyquinoline incubation did not decrease deferasirox activity in K562 cells suggesting the mechanism of action of the drug is independent from cell iron deprivation by chelation. Finally, incubation with both etoposide and deferasirox induced an increase in K562 apoptotic rate. Conclusions Nuclear factor-κB inhibition by deferasirox is not seen from other chelators and is iron and reactive oxygen species scavenging independent. This could explain the hemoglobin improvement after in vivo treatment, such that our hypothesis needs to be validated in further prospective studies. PMID:20534700

  10. Curcumin inhibits apoptosis by regulating intracellular calcium release, reactive oxygen species and mitochondrial depolarization levels in SH-SY5Y neuronal cells.

    PubMed

    Uğuz, Abdülhadi Cihangir; Öz, Ahmi; Nazıroğlu, Mustafa

    2016-08-01

    Neurological diseases such as Alzheimer's and Parkinson's diseases are incurable progressive neurological disorders caused by the degeneration of neuronal cells and characterized by motor and non-motor symptoms. Curcumin, a turmeric product, is an anti-inflammatory agent and an effective reactive oxygen and nitrogen species scavenging molecule. Hydrogen peroxide (H2O2) is the main source of oxidative stress, which is claimed to be the major source of neurological disorders. Hence, in this study we aimed to investigate the effect of curcumin on Ca(2+) signaling, oxidative stress parameters, mitochondrial depolarization levels and caspase-3 and -9 activities that are induced by the H2O2 model of oxidative stress in SH-SY5Y neuronal cells. SH-SY5Y neuronal cells were divided into four groups namely, the control, curcumin, H2O2, and curcumin + H2O2 groups. The dose and duration of curcumin and H2O2 were determined from published data. The cells in the curcumin, H2O2, and curcumin + H2O2 groups were incubated for 24 h with 5 µM curcumin and 100 µM H2O2. Lipid peroxidation and cytosolic free Ca(2+) concentrations were higher in the H2O2 group than in the control group; however, their levels were lower in the curcumin and curcumin + H2O2 groups than in the H2O2 group alone. Reduced glutathione (GSH) and glutathione peroxidase (GSH-Px) values were lower in the H2O2 group although they were higher in the curcumin and curcumin + H2O2 groups than in the H2O2 group. Caspase-3 activity was lower in the curcumin group than in the H2O2 group. In conclusion, curcumin strongly induced modulator effects on oxidative stress, intracellular Ca(2+) levels, and the caspase-3 and -9 values in an experimental oxidative stress model in SH-SY5Y cells.

  11. An Apoplastic H-Type Thioredoxin Is Involved in the Stress Response through Regulation of the Apoplastic Reactive Oxygen Species in Rice1[C][W][OA

    PubMed Central

    Zhang, Cui-Jun; Zhao, Bing-Chun; Ge, Wei-Na; Zhang, Ya-Fang; Song, Yun; Sun, Da-Ye; Guo, Yi

    2011-01-01

    Thioredoxins (Trxs) are a multigenic family of proteins in plants that play a critical role in redox balance regulation through thiol-disulfide exchange reactions. There are 10 members of the h-type Trxs in rice (Oryza sativa), and none of them has been clearly characterized. Here, we demonstrate that OsTRXh1, a subgroup I h-type Trx in rice, possesses reduction activity in vitro and complements the hydrogen peroxide sensitivity of Trx-deficient yeast mutants. OsTRXh1 is ubiquitously expressed in rice, and its expression is induced by salt and abscisic acid treatments. Intriguingly, OsTRXh1 is secreted into the extracellular space, and salt stress in the apoplast of rice induces its expression at the protein level. The knockdown of OsTRXh1 results in dwarf plants with fewer tillers, whereas the overexpression of OsTRXh1 leads to a salt-sensitive phenotype in rice. In addition, both the knockdown and overexpression of OsTRXh1 decrease abscisic acid sensitivity during seed germination and seedling growth. We also analyzed the levels of hydrogen peroxide produced in transgenic plants, and the results show that more hydrogen peroxide is produced in the extracellular space of OsTRXh1 knockdown plants than in wild-type plants, whereas the OsTRXh1 overexpression plants produce less hydrogen peroxide under salt stress. These results show that OsTRXh1 regulates the redox state of the apoplast and influences plant development and stress responses. PMID:22010108

  12. Regulation of basement membrane-reactive B cells in BXSB, (NZBxNZW)F1, NZB, and MRL/lpr lupus mice

    PubMed Central

    Clark, Amy G.; Fan, Qihua; Brady, Graham F.; Mackin, Katherine M.; Coffman, Evan D.; Weston, Melissa L.; Foster, Mary H.

    2013-01-01

    Autoantibodies to diverse antigens escape regulation in systemic lupus erythematosus under the influence of a multitude of predisposing genes. To gain insight into the differential impact of diverse genetic backgrounds on tolerance mechanisms controlling autoantibody production in lupus, we established a single lupus-derived nephritis associated anti-basement membrane Ig transgene on each of four inbred murine lupus strains, including BXSB, (NZBxNZW)F1, NZB, and MRL/lpr, as approved by the Duke University and the Durham Veterans Affairs Medical Centers’ Animal Care and Use Committees. In nonautoimmune C57BL/6 mice, B cells bearing this anti-laminin Ig transgene are stringently regulated by central deletion, editing, and anergy. Here, we show that tolerance is generally intact in unmanipulated Ig transgenic BXSB, (NZBxNZW)F1, and NZB mice, based on absence of serum transgenic anti-laminin autoantibodies and failure to recover spontaneous anti-laminin monoclonal antibodies. Four- to six-fold depletion of splenic B cells in transgenic mice of these strains, as well as in MRL/lpr transgenic mice, and reduced frequency of IgM+ bone marrow B cells suggest that central deletion is grossly intact. Nonetheless the four strains demonstrate distinct transgenic B cell phenotypes, including endotoxin-stimulated production of anti-laminin antibodies by B cells from transgenic NZB mice, and in vitro hyperproliferation of both endotoxin- and BCR-stimulated B cells from transgenic BXSB mice, which are shown to have an enrichment of CD21-high marginal zone cells. Rare anti-laminin transgenic B cells spontaneously escape tolerance in MRL/lpr mice. Further study of the mechanisms underlying these strain-specific B cell fates will provide insight into genetic modification of humoral autoimmunity in lupus. PMID:23157336

  13. Static DC to DC Power Conditioning-Active Ripple Filter, 1 MHZ DC to DC Conversion, and Nonlinear Analysis. Ph.D. Thesis; [voltage regulation and conversion circuitry for spacecraft power supplies

    NASA Technical Reports Server (NTRS)

    Sander, W. A., III

    1973-01-01

    Dc to dc static power conditioning systems on unmanned spacecraft have as their inputs highly fluctuating dc voltages which they condition to regulated dc voltages. These input voltages may be less than or greater than the desired regulated voltages. The design of two circuits which address specific problems in the design of these power conditioning systems and a nonlinear analysis of one of the circuits are discussed. The first circuit design is for a nondissipative active ripple filter which uses an operational amplifier to amplify and cancel the sensed ripple voltage. A dc to dc converter operating at a switching frequency of 1 MHz is the second circuit discussed. A nonlinear analysis of the type of dc to dc converter utilized in designing the 1 MHz converter is included.

  14. NSAIDs may regulate EGR-1-mediated induction of reactive oxygen species and non-steroidal anti-inflammatory drug-induced gene (NAG)-1 to initiate intrinsic pathway of apoptosis for the chemoprevention of colorectal cancer.

    PubMed

    Vaish, Vivek; Piplani, Honit; Rana, Chandan; Vaiphei, Kim; Sanyal, Sankar Nath

    2013-06-01

    This study aims to investigate the unclear molecular relationship involved in the activation of intrinsic pathway of apoptosis and NSAID-activated gene-1 (NAG-1) induction as a putative target in NSAIDs-mediated chemoprevention of colorectal cancer. Male Sprague-Dawley rats were administered with a colon-specific pro-carcinogen, 1,2-dimethylhydrazine dihydrochloride to achieve the early stages of colorectal cancer. Histopathological examination was performed for the analysis of neoplastic lesions while flow cytometry was performed for the relative quantification of intracellular reactive oxygen species (ROS), differential mitochondrial membrane potential (MMP or ΔΨ(M)), and apoptotic events. Various target biomolecules were analyzed either for their mRNA or protein expression profiles via RT-PCR and quantitative Real-Time PCR, or Western blotting and immunofluorescence, respectively. Enhanced gene as well as protein expression of pro-apoptotic agents was observed with the daily oral administration of two NSAIDs viz. Sulindac (cyclooxygenase (COX)-non-specific) and Celecoxib (a selective COX-2 inhibitor). A significant increase in early growth response-1 (EGR-1) protein expression and nuclear localization in NSAIDs co-administered animals may have positively regulated the expression of NAG-1 with a significant enhancement of intracellular ROS in turn decreasing the ΔΨ(M) to initiate apoptosis. In silico molecular docking analysis also showed that Sulindac and Celecoxib can block the active site pocket of B-cell lymphoma-extra large (Bcl-xL, anti-apoptotic transmembrane mitochondrial protein) which could be a putative mechanism followed by these NSAIDs to overcome anti-apoptotic properties of the molecule. NSAIDs-mediated up-regulation of EGR-1 and thereby NAG-1 along with implication of higher ROS load may positively regulate the intrinsic pathway of apoptosis for the chemoprevention of colorectal cancer.

  15. Curcumin-loaded nanoparticles induce apoptotic cell death through regulation of the function of MDR1 and reactive oxygen species in cisplatin-resistant CAR human oral cancer cells.

    PubMed

    Chang, Pei-Ying; Peng, Shu-Fen; Lee, Chao-Ying; Lu, Chi-Cheng; Tsai, Shih-Chang; Shieh, Tzong-Ming; Wu, Tian-Shung; Tu, Ming-Gene; Chen, Michael Yuanchien; Yang, Jai-Sing

    2013-10-01

    Curcumin is a polyphenolic compound which possesses anticancer potential. It has been shown to induce cell death in a variety of cancer cells, however, its effect on CAL27‑cisplatin-resistant human oral cancer cells (CAR cells) has not been elucidated to date. The low water solubility of curcumin which leads to poor bioavailability, however, has been highlighted as a major limiting factor. In this study, we utilized water-soluble PLGA curcumin nanoparticles (Cur-NPs), and investigated the effects of Cur-NPs on CAR cells. The results showed Cur-NPs induced apoptosis in CAR cells but exhibited low cytotoxicity to normal human gingival fibroblasts (HGFs) and normal human oral keratinocytes (OKs). Cur-NPs triggered DNA concentration, fragmentation and subsequent apoptosis. Compared to untreated CAR cells, a more detectable amount of Calcein-AM accumulation was found inside the treated CAR cells. Cur-NPs suppressed the protein and mRNA expression levels of MDR1. Both the activity and the expression levels of caspase-3 and caspase-9 were elevated in the treated CAR cells. The Cur-NP-triggered apoptosis was blocked by specific inhibitors of pan-caspase (z-VAD-fmk), caspase-3 (z-DEVD-fmk), caspase-9 (z-LEHD-fmk) and antioxidant agent (N-acetylcysteine; NAC). Cur-NPs increased reactive oxygen species (ROS) production, upregulated the protein expression levels of cleaved caspase-3/caspase-9, cytochrome c, Apaf-1, AIF, Bax and downregulated the protein levels of Bcl-2. Our results suggest that Cur-NPs triggered the intrinsic apoptotic pathway through regulating the function of multiple drug resistance protein 1 (MDR1) and the production of reactive oxygen species (ROS) in CAR cells. Cur-NPs could be potentially efficacious in the treatment of cisplatin-resistant human oral cancer.

  16. Combined Heat and Power (CHP) as a Compliance Option under the Clean Power Plan: A Template and Policy Options for State Regulators

    SciTech Connect

    2015-07-30

    Combined Heat and Power (CHP) is an important option for states to consider in developing strategies to meet their emission targets under the US Environmental Protection Agency's Clean Power Plan. This Template is designed to highlight key issues that states should consider when evaluating whether CHP could be a meaningful component of their compliance plans. It demonstrates that CHP can be a valuable approach for reducing emissions and helping states achieve their targets. While the report does not endorse any particular approach for any state, and actual plans will vary dependent upon state-specific factors and determinations, it provides tools and resources that states can use to begin the process, and underscores the opportunity CHP represents for many states. . By producing both heat and electricity from a single fuel source, CHP offers significant energy savings and carbon emissions benefits over the separate generation of heat and power, with a typical unit producing electricity with half the emissions of conventional generation. These efficiency gains translate to economic savings and enhanced competitiveness for CHP hosts, and emissions reductions for the state, along with helping to lower electric bills; and creating jobs in the design, construction, installation and maintenance of equipment. In 2015, CHP represents 8 percent of electric capacity in the United States and provides 12 percent of total power generation. Projects already exist in all 50 states, but significant technical and economic potential remains. CHP offers a tested way for states to achieve their emission limits while advancing a host of ancillary benefits.

  17. Power flow controller with a fractionally rated back-to-back converter

    DOEpatents

    Divan, Deepakraj M.; Kandula, Rajendra Prasad; Prasai, Anish

    2016-03-08

    A power flow controller with a fractionally rated back-to-back (BTB) converter is provided. The power flow controller provide dynamic control of both active and reactive power of a power system. The power flow controller inserts a voltage with controllable magnitude and phase between two AC sources at the same frequency; thereby effecting control of active and reactive power flows between the two AC sources. A transformer may be augmented with a fractionally rated bi-directional Back to Back (BTB) converter. The fractionally rated BTB converter comprises a transformer side converter (TSC), a direct-current (DC) link, and a line side converter (LSC). By controlling the switches of the BTB converter, the effective phase angle between the two AC source voltages may be regulated, and the amplitude of the voltage inserted by the power flow controller may be adjusted with respect to the AC source voltages.

  18. Primary-Side Power Flow Control of Wireless Power Transfer for Electric Vehicle Charging

    SciTech Connect

    Miller, John M.; Onar, Omer C.; Chinthavali, Madhu

    2014-12-22

    Various noncontacting methods of plug-in electric vehicle charging are either under development or now deployed as aftermarket options in the light-duty automotive market. Wireless power transfer (WPT) is now the accepted term for wireless charging and is used synonymously for inductive power transfer and magnetic resonance coupling. WPT technology is in its infancy; standardization is lacking, especially on interoperability, center frequency selection, magnetic fringe field suppression, and the methods employed for power flow regulation. This paper proposes a new analysis concept for power flow in WPT in which the primary provides frequency selection and the tuned secondary, with its resemblance to a power transmission network having a reactive power voltage control, is analyzed as a transmission network. Analysis is supported with experimental data taken from Oak Ridge National Laboratory s WPT apparatus. Lastly, this paper also provides an experimental evidence for frequency selection, fringe field assessment, and the need for low-latency communications in the feedback path.

  19. Method for generating a highly reactive plasma for exhaust gas after treatment and enhanced catalyst reactivity

    SciTech Connect

    Whealton, John H.; Hanson, Gregory R.; Storey, John M.; Raridon, Richard J.; Armfield, Jeffrey S.; Bigelow, Timothy S.; Graves, Ronald L.

    2000-07-01

    This patent application describes a method and apparatus of exhaust gas remediation that enhance the reactivity of the material catalysts found within catalytic converters of cars, trucks, and power stations.

  20. A novel flattop current regulated energy discharge type pulsed power supply and magnet yielding 4. 4 kGauss-meter for 6 milliseconds

    SciTech Connect

    Visser, A.T.

    1989-07-01

    Most energy discharge power supplies obtain their bursts of power from the energy stored in charged capacitors when it is suddenly released into a load. This note describes the design of a similar small 800 Joules energy discharge type power supply and magnet. The magnet gap is 2 in.{times}2 in.{times}25-1/2 in. long and produces about 4.4 kGauss-meters at a rate of 12 pulses per minute. Each pulse is current regulated at the top for a duration of 6 msec. and varies less than 0.6% of set value. Current regulation at flattop is obtained by switching a resistor in and out of the discharge circuit with an IGBT at a rate of about 5 kHz. Most energy discharge systems produce half sine wave pulses, and current regulation is obtained by controlling the charge voltage at the energy storage capacitor, resulting only in a controlled peak current value of the half sine wave pulse. The current value at the top changes substantially during 6 msec. depending on the operating frequency.

  1. Dynamin 2 and c-Abl are novel regulators of hyperoxia-mediated NADPH oxidase activation and reactive oxygen species production in caveolin-enriched microdomains of the endothelium.

    PubMed

    Singleton, Patrick A; Pendyala, Srikanth; Gorshkova, Irina A; Mambetsariev, Nurbek; Moitra, Jaideep; Garcia, Joe G N; Natarajan, Viswanathan

    2009-12-11

    Reactive oxygen species (ROS) generation, particularly by the endothelial NADPH oxidase family of proteins, plays a major role in the pathophysiology associated with lung inflammation, ischemia/reperfusion injury, sepsis, hyperoxia, and ventilator-associated lung injury. We examined potential regulators of ROS production and discovered that hyperoxia treatment of human pulmonary artery endothelial cells induced recruitment of the vesicular regulator, dynamin 2, the non-receptor tyrosine kinase, c-Abl, and the NADPH oxidase subunit, p47(phox), to caveolin-enriched microdomains (CEMs). Silencing caveolin-1 (which blocks CEM formation) and/or c-Abl expression with small interference RNA inhibited hyperoxia-mediated tyrosine phosphorylation and association of dynamin 2 with p47(phox) and ROS production. In addition, treatment of human pulmonary artery endothelial cells with dynamin 2 small interfering RNA or the dynamin GTPase inhibitor, Dynasore, attenuated hyperoxia-mediated ROS production and p47(phox) recruitment to CEMs. Using purified recombinant proteins, we observed that c-Abl tyrosine-phosphorylated dynamin 2, and this phosphorylation increased p47(phox)/dynamin 2 association (change in the dissociation constant (K(d)) from 85.8 to 6.9 nm). Furthermore, exposure of mice to hyperoxia increased ROS production, c-Abl activation, dynamin 2 association with p47(phox), and pulmonary leak, events that were attenuated in the caveolin-1 knock-out mouse confirming a role for CEMs in ROS generation. These results suggest that hyperoxia induces c-Abl-mediated dynamin 2 phosphorylation required for recruitment of p47(phox) to CEMs and subsequent ROS production in lung endothelium.

  2. Bilirubin inhibits the up-regulation of inducible nitric oxide synthase by scavenging reactive oxygen species generated by the toll-like receptor 4-dependent activation of NADPH oxidase.

    PubMed

    Idelman, Gila; Smith, Darcey L H; Zucker, Stephen D

    2015-08-01

    It has been previously shown that bilirubin prevents the up-regulation of inducible nitric oxide synthase (iNOS) in response to LPS. The present study examines whether this effect is exerted through modulation of Toll-Like Receptor-4 (TLR4) signaling. LPS-stimulated iNOS and NADPH oxidase (Nox) activity in RAW 264.7 murine macrophages was assessed by measuring cellular nitrate and superoxide ( [Formula: see text] ) production, respectively. The generation of both nitrate and [Formula: see text] in response to LPS was suppressed by TLR4 inhibitors, indicating that activation of iNOS and Nox is TLR4-dependent. While treatment with superoxide dismutase (SOD) and bilirubin effectively abolished LPS-mediated [Formula: see text] production, hydrogen peroxide and nitrate release were inhibited by bilirubin and PEG-catalase, but not SOD, supporting that iNOS activation is primarily dependent upon intracellular H2O2. LPS treatment increased nuclear translocation of the redox-sensitive transcription factor Hypoxia Inducible Factor-1α (HIF-1α), an effect that was abolished by bilirubin. Cells transfected with murine iNOS reporter constructs in which the HIF-1α-specific hypoxia response element was disrupted exhibited a blunted response to LPS, supporting that HIF-1α mediates Nox-dependent iNOS expression. Bilirubin, but not SOD, blocked the cellular production of interferon-β, while interleukin-6 production remained unaffected. These data support that bilirubin inhibits the TLR4-mediated up-regulation of iNOS by preventing activation of HIF-1α through scavenging of Nox-derived reactive oxygen species. Bilirubin also suppresses interferon-β release via a ROS-independent mechanism. These findings characterize potential mechanisms for the anti-inflammatory effects of bilirubin.

  3. System for reactivating catalysts

    SciTech Connect

    Ginosar, Daniel M.; Thompson, David N.; Anderson, Raymond P.

    2010-03-02

    A method of reactivating a catalyst, such as a solid catalyst or a liquid catalyst is provided. The method comprises providing a catalyst that is at least partially deactivated by fouling agents. The catalyst is contacted with a fluid reactivating agent that is at or above a critical point of the fluid reactivating agent and is of sufficient density to dissolve impurities. The fluid reactivating agent reacts with at least one fouling agent, releasing the at least one fouling agent from the catalyst. The at least one fouling agent becomes dissolved in the fluid reactivating agent and is subsequently separated or removed from the fluid reactivating agent so that the fluid reactivating agent may be reused. A system for reactivating a catalyst is also disclosed.

  4. Reactive capability limitation of synchronous machines

    SciTech Connect

    Adibi, M.M. ); Milanicz, D.P. )

    1994-02-01

    Achievable generator reactive capability (GRC) is generally much less than indicated by manufacturers' reactive capability curves, due to constraints imposed by plant auxiliaries and the power system itself. The nature of these constraints is explained and a method for calculating them is provided and verified by field tests on a unit at high and low system voltage levels. Several recommendations are made to enhance the GRC of the tested unit.

  5. Optimal reactive planning with security constraints

    SciTech Connect

    Thomas, W.R.; Cheng, D.T.Y.; Dixon, A.M.; Thorp, J.D.; Dunnett, R.M.; Schaff, G.

    1995-12-31

    The National Grid Company (NGC) of England and Wales has developed a computer program, SCORPION, to help system planners optimize the location and size of new reactive compensation plant on the transmission system. The reactive power requirements of the NGC system have risen as a result of increased power flows and the shorter timescale on which power stations are commissioned and withdrawn from service. In view of the high costs involved, it is important that reactive compensation be installed as economically as possible, without compromising security. Traditional methods based on iterative use of a load flow program are labor intensive and subjective. SCORPION determines a near-optimal pattern of new reactive sources which are required to satisfy voltage constraints for normal and contingent states of operation of the transmission system. The algorithm processes the system states sequentially, instead of optimizing all of them simultaneously. This allows a large number of system states to be considered with an acceptable run time and computer memory requirement. Installed reactive sources are treated as continuous, rather than discrete, variables. However, the program has a restart facility which enables the user to add realistically sized reactive sources explicitly and thereby work towards a realizable solution to the planning problem.

  6. Industrial Power Factor Analysis Guidebook.

    SciTech Connect

    Electrotek Concepts.

    1995-03-01

    Power factor is a way of measuring the percentage of reactive power in an electrical system. Reactive power represents wasted energy--electricity that does no useful work because the electrical current is out of phase with the voltage. Reactive power is used by inductive loads (such as, motors, transformers, fluorescent lights, arc welders and induction furnaces) to sustain their magnetic fields. Electric systems with many motors exhibit low power factors, increased conductor and transformer losses, and lower voltages. Utilities must supply both active and reactive power and compensate for these losses. Power factor can be improved by the addition of shunt capacitors. Capacitors act in opposition to inductive loads, thereby minimizing the reactive power required to serve them. In raising the power factor, shunt capacitors release energy to the system, reduce system losses, and ultimately decrease power costs. Improving system power factor can reduce reactive and active power losses for both industry and utilities through the addition of shunt capacitors. This Guide Book gives electric utility technical staff, industrial end-users, consultants and BPA employees a step-by-step method for evaluating the cost effectiveness of installing power factor correction capacitors in an industrial plant.

  7. Power sector policy reforms

    SciTech Connect

    Moscote, R.A. . LAC Technical Dept.)

    1994-06-01

    This article discusses the changes in energy policy of most countries in the Latin American and the Caribbean region. The topics of the article include the new legal and regulatory frameworks being developed, investment, privatized power producers, government regulation, power distribution, power transmission, access to transmission lines, pricing regulations, and increasing capacity of the power systems.

  8. Electric power

    SciTech Connect

    Chase, M.

    1988-01-01

    This text examines the critical problems faced by the electric power industry, shown in the context of a detailed description of the history and development of the industry. A new industry initiative is proposed that will allow for a more effective response to industry fluctuations. Topics covered include developments in power technology federal nuclear power regulation and legislation, environmentalism and conservationism, industry financial problems, capital minimization, and responses to utility responsibility.

  9. Induction of the mitochondria-mediated apoptosis in human esophageal cancer cells by DS2, a newly synthetic diterpenoid analog, is regulated by Bax and caused by generation of reactive oxygen species

    PubMed Central

    Zi, Xiaolin; Zhao, Fei; Yuan, Lin; Zhu, Ying-Li; Fan, Xia-Xia; Zhao, Ning-Min; Li, Qiao-Yan; Qin, Yu-Hua; Liu, Hong-Min

    2016-01-01

    Ent-kaurane diterpene compounds have attracted considerable attention in recent years due to its antitumor, antibacterial, and antiviral activities. However, the clinical development of natural kaurane diterpenes, for example, oridonin for cancer therapy has been hampered by its relatively moderate potency, limited bioavailability. Herein, we report a newly synthetic analog of natural ent-kaurane diterpene, DS2, which exhibits significantly improved activity of antiproliferation against various cancer cell lines relative to oridonin. DS2 treatment triggers the mitochondria-mediated apoptosis and cell cycle arrest in human esophageal cancer cell lines (EC9706, EC109). Interestingly, normal human esophageal epithelial cells (HEECs) and normal human liver cells (HL-7702) are both significantly more resistant to the growth inhibition by DS2 compared with esophageal cancer cells. The DS2-induced apoptosis in EC9706 cells correlated with the drop of mitochondrial membrane potential (MMP), release of cytochrome c into the cytosol and activation of caspase-9 and -3. The induction of proapoptotic proteins p21 and Bax were also observed in DS2-treated cells. The DS2-induced apoptosis was significantly attenuated by knockdown of Bax proteins. Meanwhile, the DS2 treatment caused generation of reactive oxygen species (ROS) in human esophageal cancer cells, but not in HEECs, which was attenuated by pretreatment with ROS scavenger N-acetylcysteine (NAC). More interestingly, the antioxidants pretreatment completely attenuated DS2 mediated loss of the MMP and apoptosis, as well as Bax expression and growth inhibition. In conclusion, the present study reveals that the mitochondria-mediated cell death by DS2 is associated with Bax regulation and ROS generation, and understanding the function and mechanism of DS2 will help us to design better anti-cancer drugs. PMID:27863415

  10. Induction of the mitochondria-mediated apoptosis in human esophageal cancer cells by DS2, a newly synthetic diterpenoid analog, is regulated by Bax and caused by generation of reactive oxygen species.

    PubMed

    Ma, Yong-Cheng; Ke, Yu; Zi, Xiaolin; Zhao, Fei; Yuan, Lin; Zhu, Ying-Li; Fan, Xia-Xia; Zhao, Ning-Min; Li, Qiao-Yan; Qin, Yu-Hua; Liu, Hong-Min

    2016-12-27

    Ent-kaurane diterpene compounds have attracted considerable attention in recent years due to its antitumor, antibacterial, and antiviral activities. However, the clinical development of natural kaurane diterpenes, for example, oridonin for cancer therapy has been hampered by its relatively moderate potency, limited bioavailability. Herein, we report a newly synthetic analog of natural ent-kaurane diterpene, DS2, which exhibits significantly improved activity of antiproliferation against various cancer cell lines relative to oridonin. DS2 treatment triggers the mitochondria-mediated apoptosis and cell cycle arrest in human esophageal cancer cell lines (EC9706, EC109). Interestingly, normal human esophageal epithelial cells (HEECs) and normal human liver cells (HL-7702) are both significantly more resistant to the growth inhibition by DS2 compared with esophageal cancer cells. The DS2-induced apoptosis in EC9706 cells correlated with the drop of mitochondrial membrane potential (MMP), release of cytochrome c into the cytosol and activation of caspase-9 and -3. The induction of proapoptotic proteins p21 and Bax were also observed in DS2-treated cells. The DS2-induced apoptosis was significantly attenuated by knockdown of Bax proteins. Meanwhile, the DS2 treatment caused generation of reactive oxygen species (ROS) in human esophageal cancer cells, but not in HEECs, which was attenuated by pretreatment with ROS scavenger N-acetylcysteine (NAC). More interestingly, the antioxidants pretreatment completely attenuated DS2 mediated loss of the MMP and apoptosis, as well as Bax expression and growth inhibition. In conclusion, the present study reveals that the mitochondria-mediated cell death by DS2 is associated with Bax regulation and ROS generation, and understanding the function and mechanism of DS2 will help us to design better anti-cancer drugs.

  11. Reactive oxygen species-dependent apoptosis by gugulipid extract of Ayurvedic medicine plant Commiphora mukul in human prostate cancer cells is regulated by c-Jun N-terminal kinase.

    PubMed

    Xiao, Dong; Zeng, Yan; Prakash, Lakshmi; Badmaev, Vladmir; Majeed, Muhammed; Singh, Shivendra V

    2011-03-01

    Gugulipid (GL), extract of Indian Ayurvedic medicinal plant Commiphora mukul, has been used to treat a variety of ailments. We report an anticancer effect and mechanism of GL against human prostate cancer cells. Treatment with GL significantly inhibited the viability of human prostate cancer cell line LNCaP (androgen-dependent) and its androgen-independent variant (C81) with an IC(50) of ∼1 μM (24-h treatment), at pharmacologically relevant concentrations standardized to its major active constituent z-guggulsterone. The GL-induced growth inhibition correlated with apoptosis induction as evidenced by an increase in cytoplasmic histone-associated DNA fragmentation and sub-G(0)/G(1)-DNA fraction, and cleavage of poly(ADP-ribose) polymerase. The GL-induced apoptosis was associated with reactive oxygen species (ROS) production and c-Jun NH(2)-terminal kinase (JNK) activation. The induction of proapoptotic Bcl-2 family proteins Bax and Bak and a decrease of antiapoptotic Bcl-2 protein Bcl-2 were observed in GL-treated cells. SV40 immortalized mouse embryonic fibroblasts derived from Bax-Bak double-knockout mice were significantly more resistant to GL-induced cell killing compared with wild-type cells. It is interesting to note that a representative normal prostate epithelial cell line (PrEC) was relatively more resistant to GL-mediated cellular responses compared with prostate cancer cells. The GL treatment caused the activation of JNK that functioned upstream of Bax activation in apoptosis response. The GL-induced conformational change of Bax and apoptosis were significantly suppressed by genetic suppression of JNK activation. In conclusion, the present study indicates that ROS-dependent apoptosis by GL is regulated by JNK signaling axis.

  12. Risk-informed regulation and safety management of nuclear power plants--on the prevention of severe accidents.

    PubMed

    Himanen, Risto; Julin, Ari; Jänkälä, Kalle; Holmberg, Jan-Erik; Virolainen, Reino

    2012-11-01

    There are four operating nuclear power plant (NPP) units in Finland. The Teollisuuden Voima (TVO) power company has two 840 MWe BWR units supplied by Asea-Atom at the Olkiluoto site. The Fortum corporation (formerly IVO) has two 500 MWe VVER 440/213 units at the Loviisa site. In addition, a 1600 MWe European Pressurized Water Reactor supplied by AREVA NP (formerly the Framatome ANP--Siemens AG Consortium) is under construction at the Olkiluoto site. Recently, the Finnish Parliament ratified the government Decision in Principle that the utilities' applications to build two new NPP units are in line with the total good of the society. The Finnish utilities, Fenno power company, and TVO company are in progress of qualifying the type of the new nuclear builds. In Finland, risk-informed applications are formally integrated in the regulatory process of NPPs that are already in the early design phase and these are to run through the construction and operation phases all through the entire plant service time. A plant-specific full-scope probabilistic risk assessment (PRA) is required for each NPP. PRAs shall cover internal events, area events (fires, floods), and external events such as harsh weather conditions and seismic events in all operating modes. Special attention is devoted to the use of various risk-informed PRA applications in the licensing of Olkiluoto 3 NPP.

  13. Optimal Power Flow Pursuit

    SciTech Connect

    Dall'Anese, Emiliano

    2016-08-01

    Past works that focused on addressing power-quality and reliability concerns related to renewable energy resources (RESs) operating with business-as-usual practices have looked at the design of Volt/VAr and Volt/Watt strategies to regulate real or reactive powers based on local voltage measurements, so that terminal voltages are within acceptable levels. These control strategies have the potential of operating at the same time scale of distribution-system dynamics, and can therefore mitigate disturbances precipitated fast time-varying loads and ambient conditions; however, they do not necessarily guarantee system-level optimality, and stability claims are mainly based on empirical evidences. On a different time scale, centralized and distributed optimal power flow (OPF) algorithms have been proposed to compute optimal steady-state inverter setpoints, so that power losses and voltage deviations are minimized and economic benefits to end-users providing ancillary services are maximized. However, traditional OPF schemes may offer decision making capabilities that do not match the dynamics of distribution systems. Particularly, during the time required to collect data from all the nodes of the network (e.g., loads), solve the OPF, and subsequently dispatch setpoints, the underlying load, ambient, and network conditions may have already changed; in this case, the DER output powers would be consistently regulated around outdated setpoints, leading to suboptimal system operation and violation of relevant electrical limits. The present work focuses on the synthesis of distributed RES-inverter controllers that leverage the opportunities for fast feedback offered by power-electronics interfaced RESs. The overarching objective is to bridge the temporal gap between long-term system optimization and real-time control, to enable seamless RES integration in large scale with stability and efficiency guarantees, while congruently pursuing system-level optimization objectives. The

  14. Phenylethynyl reactive diluents

    NASA Technical Reports Server (NTRS)

    Bryant, Robert G. (Inventor); Jensen, Brian J. (Inventor); Hergenrother, Paul M. (Inventor)

    1995-01-01

    A composition of matter having a specified general structure is employed to terminate a nucleophilic reagent, resulting in the exclusive production of phenylethynyl terminated reactive oligomers which display unique thermal characteristics. A reactive diluent having a specified general structure is employed to decrease the melt viscosity of a phenylethynyl terminated reactive oligomer and to subsequently react with to provide a thermosetting material of enhanced density. These materials have features which make them attractive candidates for use as composite matrices and adhesives.

  15. Planarians: a versatile and powerful model system for molecular studies of regeneration, adult stem cell regulation, aging, and behavior.

    PubMed

    Oviedo, Néstor J; Nicolas, Cindy L; Adams, Dany S; Levin, Michael

    2008-10-01

    INTRODUCTIONIn recent years, planarians have been increasingly recognized as an emerging model organism amenable to molecular genetic techniques aimed at understanding complex biological tasks commonly observed among metazoans. Growing evidence suggests that this model organism is uniquely poised to inform us about the mechanisms of tissue regeneration, stem cell regulation, tissue turnover, pharmacological action of diverse drugs, cancer, and aging. This article provides an overview of the planarian model system with special attention to the species Schmidtea mediterranea. Additionally, information is provided about the most popular use of this organism, together with modern genomic resources and technical approaches.

  16. Fabrication of a PMN-PT single crystal-based transcranial Doppler transducer and the power regulation of its detection system.

    PubMed

    Yue, Qingwen; Liu, Dongxu; Wang, Wei; Di, Wenning; Lin, Di; Wang, Xi'an; Luo, Haosu

    2014-12-19

    Doppler sonographic measurement of flow velocity in the basal cerebral arteries through the intact skull was developed using a pulsed Doppler technique and 2 MHz emitting frequency. Relaxor-based ferroelectric single crystals Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) were chosen to be the piezoelectric transducer material due to their ultrahigh piezoelectric coefficients, high electromechanical coupling coefficients and low dielectric loss. The pulse-echo response of the transducer was measured using the conventional pulse-echo method in a water bath at room temperature. The -6 dB bandwidth of the transducer is 68.4% and the sensitivity is -17.4 dB. In order to get a good match between transducer and detection system, different transmission powers have been regulated by changing the impedance of the transmitting electric circuit. In the middle cerebral artery (MCA) measurement photograph results, as the transmission power is increasing, the detection results become clearer and clearer. A comparison at the same transmission power for different transducers shows that the detection photograph obtained by the crystal transducer was clearer than that obtained with a commercial transducer, which should make it easier for doctors to find the cerebral arteries.

  17. Fabrication of a PMN-PT Single Crystal-Based Transcranial Doppler Transducer and the Power Regulation of Its Detection System

    PubMed Central

    Yue, Qingwen; Liu, Dongxu; Wang, Wei; Di, Wenning; Lin, Di; Wang, Xi'an; Luo, Haosu

    2014-01-01

    Doppler sonographic measurement of flow velocity in the basal cerebral arteries through the intact skull was developed using a pulsed Doppler technique and 2 MHz emitting frequency. Relaxor-based ferroelectric single crystals Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) were chosen to be the piezoelectric transducer material due to their ultrahigh piezoelectric coefficients, high electromechanical coupling coefficients and low dielectric loss. The pulse-echo response of the transducer was measured using the conventional pulse-echo method in a water bath at room temperature. The −6 dB bandwidth of the transducer is 68.4% and the sensitivity is −17.4 dB. In order to get a good match between transducer and detection system, different transmission powers have been regulated by changing the impedance of the transmitting electric circuit. In the middle cerebral artery (MCA) measurement photograph results, as the transmission power is increasing, the detection results become clearer and clearer. A comparison at the same transmission power for different transducers shows that the detection photograph obtained by the crystal transducer was clearer than that obtained with a commercial transducer, which should make it easier for doctors to find the cerebral arteries. PMID:25536000

  18. Regulators as agents: modelling personality and power as evidence is brokered to support decisions on environmental risk.

    PubMed

    Davies, G J; Kendall, G; Soane, E; Li, J; Rocks, S A; Jude, S R; Pollard, S J T

    2014-01-01

    Complex regulatory decisions about risk rely on the brokering of evidence between providers and recipients, and involve personality and power relationships that influence the confidence that recipients may place in the sufficiency of evidence and, therefore, the decision outcome. We explore these relationships in an agent-based model; drawing on concepts from environmental risk science, decision psychology and computer simulation. A two-agent model that accounts for the sufficiency of evidence is applied to decisions about salt intake, animal carcass disposal and radioactive waste. A dynamic version of the model assigned personality traits to agents, to explore their receptivity to evidence. Agents with 'aggressor' personality sets were most able to imbue fellow agents with enhanced receptivity (with 'avoider' personality sets less so) and clear confidence in the sufficiency of evidence. In a dynamic version of the model, when both recipient and provider were assigned the 'aggressor' personality set, this resulted in 10 successful evidence submissions in 71 days, compared with 96 days when both agents were assigned the 'avoider' personality set. These insights suggest implications for improving the efficiency and quality of regulatory decision making by understanding the role of personality and power.

  19. Reconfigurable Resonant Regulating Rectifier With Primary Equalization for Extended Coupling- and Loading-Range in Bio-Implant Wireless Power Transfer.

    PubMed

    Li, Xing; Meng, Xiaodong; Tsui, Chi-Ying; Ki, Wing-Hung

    2015-12-01

    Wireless power transfer using reconfigurable resonant regulating (R(3)) rectification suffers from limited range in accommodating varying coupling and loading conditions. A primary-assisted regulation principle is proposed to mitigate these limitations, of which the amplitude of the rectifier input voltage on the secondary side is regulated by accordingly adjusting the voltage amplitude Veq on the primary side. A novel current-sensing method and calibration scheme track Veq on the primary side. A ramp generator simultaneously provides three clock signals for different modules. Both the primary equalizer and the R(3) rectifier are implemented as custom integrated circuits fabricated in a 0.35 μm CMOS process, with the global control implemented in FPGA. Measurements show that with the primary equalizer, the workable coupling and loading ranges are extended by 250% at 120 mW load and 300% at 1.2 cm coil distance compared to the same system without the primary equalizer. A maximum rectifier efficiency of 92.5% and a total system efficiency of 62.4% are demonstrated.

  20. Low-to-Medium Power Single Chip Digital Controlled DC-DC Regulator for Point-of-Load Applications

    NASA Technical Reports Server (NTRS)

    Adell, Philippe C. (Inventor); Bakkaloglu, Bertan (Inventor); Vermeire, Bert (Inventor); Liu, Tao (Inventor)

    2015-01-01

    A DC-DC converter for generating a DC output voltage includes: a digitally controlled pulse width modulator (DPWM) for controlling a switching power stage to supply a varying voltage to an inductor; and a digital voltage feedback circuit for controlling the DPWM in accordance with a feedback voltage corresponding to the DC output voltage, the digital voltage feedback circuit including: a first voltage controlled oscillator for converting the feedback voltage into a first frequency signal and to supply the first frequency signal to a first frequency discriminator; a second voltage controlled oscillator for converting a reference voltage into a second frequency signal and to supply the second frequency signal to a second frequency discriminator; a digital comparator for comparing digital outputs of the first and second frequency discriminators and for outputting a digital feedback signal; and a controller for controlling the DPWM in accordance with the digital feedback signal.