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. 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.

  5. 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.

  6. 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.

  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. Fixed costs of providing ancillary services from power plants: Reactive supply and voltage control, regulation and frequency response, operating reserve--spinning. Final report

    SciTech Connect

    Boyle, R.; Kure-Jensen, J.

    1998-12-01

    This report describes methodologies to determine the fixed costs for a steam cycle generating unit to participate in Reactive Supply and Voltage Control (RS-VC), Regulation and Frequency Response (RFR), and Operating Reserve-Spinning (ORS) services. It is intended for use by a Generator of electricity who is planning to offer these ancillary services in a competitive market. The methodology is based on common steam power plant engineering and economic principles. Reactive supply and voltage control provides reactive supply through changes to generator reactive output to maintain acceptable transmission system voltages and facilitate electricity transfers and provides the ability to continually adjust transmission system voltage in response to system changes. Regulation and frequency response service include all rapid load changes whether their purpose is to meet the instantaneous load demand, to balance control area supply resources with load, or to maintain frequency. Spinning reserve is provided by generating units that are on-line and loaded at less than maximum output. They are available to serve load immediately in an unexpected contingency such as an unplanned outage of a generating unit.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 77 FR 11109 - Reactive Power Resources; Notice of Technical Conference

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-24

    ... Energy Regulatory Commission Reactive Power Resources; Notice of Technical Conference The Federal Energy... docket highlights potential issues regarding the need for reactive power capability among newly... technical conference to examine whether the Commission should reconsider or modify the reactive...

  16. 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.

  17. On reactive high power impulse magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Gudmundsson, J. T.

    2016-01-01

    High power impulse magnetron sputtering (HiPIMS) is an ionized physical vapor deposition (IPVD) technique that is particularly promising for reactive sputtering applications. However, there are few issues that have to be resolved before the full potential of this technique can be realized. Here we give an overview of the key experimental findings for the reactive HiPIMS discharge. An increase in the discharge current is commonly observed with increased partial pressure of the reactive gas or decreased repetition pulse frequency. There are somewhat conflicting claims regarding the hysteresis effect in the reactive HiPIMS discharge as some report reduction or elimination of the hysteresis effect while others claim a feedback control is essential. The ion energy distribution of the metal ion and the atomic ion of the reactive gas are similar and extend to very high energies while the ion energy distribution of the working gas and the molecular ion of the reactive gas are similar and are much less energetic.

  18. A heuristic method for reactive power planning

    SciTech Connect

    Mantovani, J.R.S.

    1996-02-01

    An approach for solving reactive power planning problems is presented, which is based on binary search techniques and the use of a special heuristic to obtain a discrete solution. Two versions were developed, one to run on conventional (sequential) computers and the other to run on a distributed memory (hypercube) machine. This latter parallel processing version employs an asynchronous programming model. Once the set of candidate bases has been defined, the program gives the location and size of the reactive sources needed (if any) in keeping with operating and security constraints.

  19. Comparative Studies of Particle Swarm Optimization Techniques for Reactive Power Allocation Planning in Power Systems

    NASA Astrophysics Data System (ADS)

    Fukuyama, Yoshikazu

    This paper compares particle swarm optimization (PSO) techniques for a reactive power allocation planning problem in power systems. The problem can be formulated as a mixed-integer nonlinear optimization problem (MINLP). The PSO based methods determines a reactive power allocation strategy with continuous and discrete state variables such as automatic voltage regulator (AVR) operating values of electric power generators, tap positions of on-load tap changer (OLTC) of transformers, and the number of reactive power compensation equipment. Namely, this paper investigates applicability of PSO techniques to one of the practical MINLPs in power systems. Four variations of PSO: PSO with inertia weight approach (IWA), PSO with constriction factor approach (CFA), hybrid particle swarm optimization (HPSO) with IWA, and HPSO with CFA are compared. The four methods are applied to the standard IEEE14 bus system and a practical 112 bus system.

  20. 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.

  1. 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.

  2. 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...

  3. 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.

  4. Reactive power optimization by genetic algorithm

    SciTech Connect

    Iba, Kenji )

    1994-05-01

    This paper presents a new approach to optimal reactive power planning based on a genetic algorithm. Many outstanding methods to this problem have been proposed in the past. However, most of these approaches have the common defect of being caught to a local minimum solution. The integer problem which yields integer value solutions for discrete controllers/banks still remains as a difficult one. The genetic algorithm is a kind of search algorithm based on the mechanics of natural selection and genetics. This algorithm can search for a global solution using multiple paths and treat integer problems naturally. The proposed method was applied to practical 51-bus and 224-bus systems to show its feasibility and capabilities. Although this method is not as fast as sophisticated traditional methods, the concept is quite promising and useful.

  5. Federal Powers of Regulation.

    ERIC Educational Resources Information Center

    Rhyne, William S.

    1979-01-01

    Reflects the special considerations in affecting, rather than merely evaluating, the outcome of constitutional litigation over federal regulation of state and local government labor relations. (Author/IRT)

  6. Optimized Reactive Power Compensation Using Fuzzy Logic Controller

    NASA Astrophysics Data System (ADS)

    George, S.; Mini, K. N.; Supriya, K.

    2015-03-01

    Reactive power flow in a long transmission line plays a vital role in power transfer capability and voltage stability in power system. Traditionally, shunt connected compensators are used to control reactive power in long transmission line. Thyristor controlled reactor is used to control reactive power under lightly loaded condition. By controlling firing angle of thyristor, it is possible to control reactive power in the transmission lines. However, thyristor controlled reactor will inject harmonic current into the system. An attempt to reduce reactive power injection will increase harmonic distortion in the line current and vice versa. Thus, there is a trade-off between reactive power injection and harmonics in current. By optimally controlling the reactive power injection, harmonics in current can be brought within the specified limit. In this paper, a Fuzzy Logic Controller is implemented to obtain optimal control of reactive power of the compensator to maintain voltage and harmonic in current within the limits. An algorithm which optimizes the firing angle in each fuzzy subset by calculating the rank of feasible firing angles is proposed for the construction of rules in Fuzzy Logic Controller. The novelty of the algorithm is that it uses a simple error formula for the calculation of the rank of the feasible firing angles in each fuzzy subset.

  7. Regulation of Herpesvirus Reactivation by Host MicroRNAs

    PubMed Central

    2014-01-01

    The interplay between latent and lytic modes of infection is central to successful infection of all herpesviruses, yet knowledge of the determinants that govern reactivation of these viruses from latent to lytic infection is limited. Recently, several studies have identified roles for specific cellular microRNAs in inhibiting reactivation of various herpesviruses, thereby promoting latent infections. These studies are discussed in the context of current knowledge on mechanisms of regulation of reactivation of specific herpesviruses. PMID:25540363

  8. Photovoltaic solar system connected to the electric power grid operating as active power generator and reactive power compensator

    SciTech Connect

    Albuquerque, Fabio L.; Moraes, Adelio J.; Guimaraes, Geraldo C.; Sanhueza, Sergio M.R.; Vaz, Alexandre R.

    2010-07-15

    In the case of photovoltaic (PV) systems acting as distributed generation (DG) systems, the DC energy that is produced is fed to the grid through the power-conditioning unit (inverter). The majority of contemporary inverters used in DG systems are current source inverters (CSI) operating at unity power factor. If, however, we assume that voltage source inverters (VSI) can replace CSIs, we can generate reactive power proportionally to the remaining unused capacity at any given time. According to the theory of instantaneous power, the inverter reactive power can be regulated by changing the amplitude of its output voltage. In addition, the inverter active power can be adjusted by modifying the phase angle of its output voltage. Based on such theory, both the active power supply and the reactive power compensation (RPC) can be carried out simultaneously. When the insolation is weak or the PV modules are inoperative at night, the RPC feature of a PV system can still be used to improve the inverter utilisation factor. Some MATLAB simulation results are included here to show the feasibility of the method. (author)

  9. 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.

  10. 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.

  11. REGULATION OF SPERM NUCLEAR REACTIVATION DURING FERTILIZATION

    EPA Science Inventory

    Upon fusion of sperm and oocyte at fertilization, a series of events is initiated whereby the highly compacted sperm nucleus expands and is transformed into a male pronucleus capable of DNA synthesis. The regulation of these early post-fusion fertilization events has been studied...

  12. Maximum Power Point Regulator System

    NASA Astrophysics Data System (ADS)

    Simola, J.; Savela, K.; Stenberg, J.; Tonicello, F.

    2011-10-01

    The target of the study done under the ESA contract No.17830/04/NL/EC (GSTP4) for Maximum Power Point Regulator System (MPPRS) was to investigate, design and test a modular power system (a core PCU) fulfilling requirement for maximum power transfer even after a single failure in the Power System by utilising a power concept without any potential and credible single point failure. The studied MPPRS concept is of a modular construction, able to track the MPP individually on each SA sections, maintaining its functionality and full power capability after a loss of a complete MPPR module (by utilizingN+1module).Various add-on DCDC converter topology candidates were investigated and redundancy, failure mechanisms and protection aspects were studied

  13. Assessment of the Economic Benefits from Reactive Power Compensation

    SciTech Connect

    Li, Fangxing; Kueck, John D; Rizy, D Tom; Tolbert, Leon M; Zhang, Wenjuan

    2006-01-01

    The U.S. power industry is under great pressure to provide reactive power or Var support. Although it is generally known that there are technical benefits for utilities and industrial customers to provide local reactive power support, a thorough quantitative investigation of the economic benefit is greatly needed. This paper seeks to provide a quantitative approach to evaluate the benefits from local reactive power compensation. This paper investigates the benefits including reduced losses, shifting reactive power flow to real power flow, and increased transfer capability. These benefits are illustrated with a simple two-bus model and then presented with a more complicated model using Optimal Power Flow. Tests are conducted on a system with seven buses in two areas. These simulations show that the economic benefits can be significant, if compared with capacity payment to central generators or power factor penalties applied to utilities. This economic value may give utilities a better understanding of the Var benefits to assist their cost-benefit analysis for Var compensation. In addition, since the economic benefits are significant, this paper suggests that the future reactive power market should consider local Var providers.

  14. 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…

  15. 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…

  16. 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.

  17. 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

  18. Redox signaling regulated by electrophiles and reactive sulfur species.

    PubMed

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

    2016-03-01

    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

  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. 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

  1. 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.

  2. Maternal regulation of infant reactivity from 2 to 6 months.

    PubMed

    Jahromi, Laudan B; Putnam, Samuel P; Stifter, Cynthia A

    2004-07-01

    Previous research has investigated the effect of maternal soothing behaviors on reducing infant reactivity but not the differential effects of specific maternal behaviors on infant stress responses. The present study investigated maternal regulation of 2- and 6-month-olds' responses to an inoculation and found a significant decline with age in both the intensity and duration of infants' crying. Maternal affection and touching decreased from 2 to 6 months, whereas maternal vocalizing and distraction behaviors increased. At both ages, the combination of maternal holding/rocking and vocalizing was associated with decreases in all levels of infant reactivity. Neither strategy alone, however, was found to be effective. Feeding/ pacifying behaviors were effective only when initial distress was at a low or moderate level, which suggests that the effectiveness of maternal regulatory behaviors may depend on the intensity of infants' crying. PMID:15238037

  3. Redox and Reactive Oxygen Species Regulation of Mitochondrial Cytochrome c Oxidase Biogenesis

    PubMed Central

    Bourens, Myriam; Fontanesi, Flavia; Soto, Iliana C.; Liu, Jingjing

    2013-01-01

    Abstract Significance: Cytochrome c oxidase (COX), the last enzyme of the mitochondrial respiratory chain, is the major oxygen consumer enzyme in the cell. COX biogenesis involves several redox-regulated steps. The process is highly regulated to prevent the formation of pro-oxidant intermediates. Recent Advances: Regulation of COX assembly involves several reactive oxygen species and redox-regulated steps. These include: (i) Intricate redox-controlled machineries coordinate the expression of COX isoenzymes depending on the environmental oxygen concentration. (ii) COX is a heme A-copper metalloenzyme. COX copper metallation involves the copper chaperone Cox17 and several other recently described cysteine-rich proteins, which are oxidatively folded in the mitochondrial intermembrane space. Copper transfer to COX subunits 1 and 2 requires concomitant transfer of redox power. (iii) To avoid the accumulation of reactive assembly intermediates, COX is regulated at the translational level to minimize synthesis of the heme A-containing Cox1 subunit when assembly is impaired. Critical Issues: An increasing number of regulatory pathways converge to facilitate efficient COX assembly, thus preventing oxidative stress. Future Directions: Here we will review on the redox-regulated COX biogenesis steps and will discuss their physiological relevance. Forthcoming insights into the precise regulation of mitochondrial COX biogenesis in normal and stress conditions will likely open future perspectives for understanding mitochondrial redox regulation and prevention of oxidative stress. Antioxid. Redox Signal. 19, 1940–1952. PMID:22937827

  4. Development of Voltage Reactive Power Control Considering Load Change

    NASA Astrophysics Data System (ADS)

    Shimone, Takaaki; Yatsubo, Osamu; Ishigame, Atsushi; Hasegawa, Tsuguto

    Modern power system has become large and complex networks, which require more flexible system operation. Voltage and reactive power control (VQC) that transports more electric powers especially maintaining voltages within range of constraints is expected to become more important for a high-performance system operation. In this paper, we propose a new technique of VQC considering load change with a short-term load forecasting and an optimal control by a new Meta-heuristics technique with combination of Particle Swarm Optimization (PSO) and Tabu Search (TS).

  5. 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.

  6. 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.

  7. Modified artificial bee colony algorithm for reactive power optimization

    NASA Astrophysics Data System (ADS)

    Sulaiman, Noorazliza; Mohamad-Saleh, Junita; Abro, Abdul Ghani

    2015-05-01

    Bio-inspired algorithms (BIAs) implemented to solve various optimization problems have shown promising results which are very important in this severely complex real-world. Artificial Bee Colony (ABC) algorithm, a kind of BIAs has demonstrated tremendous results as compared to other optimization algorithms. This paper presents a new modified ABC algorithm referred to as JA-ABC3 with the aim to enhance convergence speed and avoid premature convergence. The proposed algorithm has been simulated on ten commonly used benchmarks functions. Its performance has also been compared with other existing ABC variants. To justify its robust applicability, the proposed algorithm has been tested to solve Reactive Power Optimization problem. The results have shown that the proposed algorithm has superior performance to other existing ABC variants e.g. GABC, BABC1, BABC2, BsfABC dan IABC in terms of convergence speed. Furthermore, the proposed algorithm has also demonstrated excellence performance in solving Reactive Power Optimization problem.

  8. Voltage and Reactive Power Control by Parallel Calculation Processing

    NASA Astrophysics Data System (ADS)

    Michihata, Masashi; Aoki, Hidenori; Mizutani, Yoshibumi

    This paper presents a new approach to optimal voltage and reactive power control based on a genetic algorithm (GA) and a tabu search (TS). To reduce time to calculate the control procedure, the parallel computation using Linux is executed. In addition, TS and GA are calculated by the master and each slave based on the parallel program language. The effectiveness of the proposed method is demonstrated by practical 118-bus system.

  9. Distributed control of reactive power flow in a radial distribution circuit with high photovoltaic penetration

    SciTech Connect

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

    2009-01-01

    We show how distributed control of reactive power can serve to regulate voltage and minimize resistive losses in a distribution circuit that includes a significant level of photovoltaic (PV) generation. To demonstrate the technique, we consider a radial distribution circuit with a single branch consisting of sequentially-arranged residential-scale loads that consume both real and reactive power. In parallel, some loads also have PV generation capability. We postulate that the inverters associated with each PV system are also capable of limited reactive power generation or consumption, and we seek to find the optimal dispatch of each inverter's reactive power to both maintain the voltage within an acceptable range and minimize the resistive losses over the entire circuit. We assume the complex impedance of the distribution circuit links and the instantaneous load and PV generation at each load are known. We compare the results of the optimal dispatch with a suboptimal local scheme that does not require any communication. On our model distribution circuit, we illustrate the feasibility of high levels of PV penetration and a significant (20% or higher) reduction in losses.

  10. Controller Regulates Auxiliary Source for Solar Power

    NASA Technical Reports Server (NTRS)

    Nola, F. J.

    1982-01-01

    Load driven by two motors continuously draws power from a varying source (solar cells) and steady auxiliary source (utility company). Power-factor controller apportions electrical load between two sources to maintain motor speed. This novel application of power-factor controller would regulate input of auxiliary energy to a solar-powered system in response to availability of Sunlight.

  11. 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.

  12. Minimization of Reactive Power Fluctuation in JT-60SA Magnet Power Supply

    NASA Astrophysics Data System (ADS)

    Shimada, K.; Terakado, T.; Yamauchi, K.; Matsukawa, M.; Baulaigue, O.; Coletti, R.; Coletti, A.; Novello, L.

    2013-02-01

    This paper describes an asymmetric control method for the firing angle and a start/stop timing shift control of four thyristor converters called “Booster PS" to minimize the reactive power fluctuation during plasma initiation in JT-60SA. From the simulation using the “PSCAD/EMTDC" code, it is found that these control methods can drastically reduce the reactive power induced by the four units of the “Booster PS". In addition, the voltage fluctuation of the motor-generator connected to the “Booster PS" is expected to be suppressed. This can also contribute to achieve stable control of the JT-60SA magnet power supplies.

  13. A New Regulation for Rural Power Grid Low-Voltage Controlling

    NASA Astrophysics Data System (ADS)

    Xian, L.; Wu, L. Z.; Yu, G. K.; Zhou, H.

    To solve the low voltage problem of rural power grid, this paper proposed a new mode of regulating voltage through substation, line and distribute substation. Through establish the mathematics module to analysis the three joint voltage regulation, and the control strategy of three joint regulation is also given in this paper. Through three joint voltage and reactive power compensation regulation, the voltage quality would be improved and the network loss would be reduced.

  14. 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.

  15. A fuzzy-based optimal reactive power control

    SciTech Connect

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

    1993-05-01

    This paper presents a mathematical formulation for the optimal reactive power control problem using the fuzzy set theory. The objectives are to minimize real power losses and improve the voltage profile of a given system. Transmission loses are expressed in terms of voltage increments by relating the control variables, i.e., tap positions of transformers and reactive power injections of VAR sources, to the voltage increments in a modified Jacobian matrix. This specific formulation of the problem does not require the Jacobian matrix inversion, and hence it will save computation time and memory space. The objective function and the constraints are modeled by fuzzy sets. Linear membership functions of the fuzzy sets are defined and the fuzzy linear optimization problem is formulated. The solution space in this case is defined as the intersection of the fuzzy sets describing the constraints and the objective functions. Each solution is characterized by a parameter that determines the degree of satisfaction with the solution. The optimal solution is the one with the maximum value for the satisfaction parameter. Results for the application of this approach on test systems reveal its numerous advantages.

  16. Reactive Power Laboratory: Synchronous Condenser Testing&Modeling Results - Interim Report

    SciTech Connect

    Henry, SD

    2005-09-27

    The subject report documents the work carried out by Oak Ridge National Laboratory (ORNL) during months 5-7 (May-July 2005) of a multi-year research project. The project has the overall goal of developing methods of incorporating distributed energy (DE) that can produce reactive power locally and for injecting into the distribution system. The objective for this new type of DE is to be able to provide voltage regulation and dynamic reactive power reserves without the use of extensive communication and control systems. The work performed over this three-month period focused on four aspects of the overall objective: (1) characterization of a 250HP (about 300KVAr) synchronous condenser (SC) via test runs at the ORNL Reactive Power Laboratory; (2) development of a data acquisition scheme for collecting the necessary voltage, current and power readings at the synchronous condenser and on the distribution system; (3) development of algorithms for analyzing raw test data from the various test runs; and (4) validation of a steady-state model for the synchronous condenser via the use of a commercial software package to study its effects on the ORNL 13.8/2.4kV distribution network.

  17. Short-term scheduling of reactive power controllers

    SciTech Connect

    Hong Yingyi; Liao Csongming

    1995-05-01

    A two-level approach is presented to solve the problem of optimal short-term (one day) scheduling of reactive power controllers in this paper. The entire problem is decomposed into two levels: the master and the slave levels. The master level deals with minimization of the depreciation cost of compensators and EHV transformer taps in order to reduce the control action for compensators and EHV transformer taps while satisfying operating constraints. The slave level treats minimization of capitalized MW losses while satisfying system security constraints. The slave level also treats OLTCs and determines scheduling of the generator voltages. These two levels interact through linear constraints in the iteration process. A practical 265-bus system, namely Taiwan Power System, are used to serve as a sample to show the applicability of the presented approach.

  18. 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.

  19. 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.

  20. 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.

  1. 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...

  2. Investigation on application of genetic algorithms to optimal reactive power dispatch of power systems

    NASA Astrophysics Data System (ADS)

    Wu, Q. H.; Ma, J. T.

    1993-09-01

    A primary investigation into application of genetic algorithms in optimal reactive power dispatch and voltage control is presented. The application was achieved, based on (the United Kingdom) National Grid 48 bus network model, using a novel genetic search approach. Simulation results, compared with that obtained using nonlinear programming methods, are included to show the potential of applications of the genetic search methodology in power system economical and secure operations.

  3. Emotional reactivity and regulation in infancy interact to predict executive functioning in early childhood.

    PubMed

    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 battery at age 48 months. Results indicated that the relation of child negative emotional reactivity at 15 months of age to executive functioning at 48 months of age was dependent on observed emotion regulation. High levels of executive function ability were observed among children who exhibited high levels of emotional reactivity and high levels of the regulation of this reactivity. In contrast, low levels of executive function ability were observed among children who exhibited high levels of reactivity but low levels of regulation. Among children exhibiting low levels of emotional reactivity, emotion regulation was unrelated to executive functioning. Moreover, emotionally reactive infants exhibiting high levels of emotion regulation were more likely to have primary caregivers who exhibited high levels of positive parenting behavior in a parent-child interaction task. Results provide support for a neurobiologically informed developmental model in which the regulation of emotional arousal is one mechanism whereby supportive environments are associated with higher levels of self-regulation ability for highly reactive infants. Findings are discussed with implications for differential susceptibility and biological sensitivity theories of child by context interaction. PMID:22563678

  4. Simulation of automatic frequency and power regulators

    NASA Astrophysics Data System (ADS)

    Borovikov, Y. S.; Pischulin, A. Y.; Ufa, R. A.

    2015-10-01

    The motivation of the presented research is based on the need for development of new methods and tools for adequate real time simulation of automation control frequency and power regulators of generator played an important role in the planning, design and operation of electric power system. This paper proposes a Hybrid real time simulator of electric power system for simulation of automation control frequency and power regulators of generator. The obtained results of experimental researches of turbine emergency control of generator demonstrate high accuracy of the simulator and possibility of real-time simulation of all the processes in the electric power system without any decomposition and limitation on their duration, and the effectiveness of the proposed simulator in solving of the design, operational and research tasks of electric power system.

  5. 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

  6. 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

  7. 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

  8. 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.

  9. 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. PMID:27536512

  10. Distance Relaying with Power Swing Detection based on Voltage and Reactive Power Sensitivity

    NASA Astrophysics Data System (ADS)

    Patel, Ujjaval J.; Chothani, Nilesh G.; Bhatt, Praghnesh J.

    2016-02-01

    Sudden changes in loading or configuration of an electrical network causes power swing which may result in an unwanted tripping of the distance relay. Hence, it becomes utmost necessary to rapidly and reliably discriminate between actual fault and power swing conditions in order to prevent instability in power network due to mal operation of distance relay. This paper proposes a novel method for the discrimination between fault and power swing based on rate of change of voltage and reactive power measured at relay location. The effectiveness of the proposed algorithm is evaluated by simulating series of power swing conditions in PSCAD/EMTDC® software for different disturbances such as change in mechanical power input to synchronous generator, tripping of parallel line due to fault and sudden application of heavy load. It is revealed that the distance relay gives successful tripping in case of different fault conditions and remains inoperative for power swing with the implementation of the proposed algorithm. Moreover, the proposed scheme has ability to distinguish the symmetrical and asymmetrical fault occurrence during power swing condition.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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. PMID:27492495

  17. 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. PMID:26796572

  18. Reduced facial reactivity as a contributor to preserved emotion regulation in older adults.

    PubMed

    Pedder, David J; Terrett, Gill; Bailey, Phoebe E; Henry, Julie D; Ruffman, Ted; Rendell, Peter G

    2016-02-01

    This study investigated whether differences in the type of strategy used, or age-related differences in intensity of facial reactivity, might contribute to preserved emotion regulation ability in older adults. Young (n = 35) and older (n = 33) adults were instructed to regulate their emotion to positive and negative pictures under 3 conditions (watch, expressive suppression, cognitive 'detached' reappraisal). Participants were objectively monitored using facial electromyography (EMG) and assessed on memory performance. Both age groups were effectively, and equivalently, able to reduce their facial expressions. In relation to facial reactivity, the percentage increase of older adults' facial muscle EMG activity in the watch condition was significantly reduced relative to young adults. Recall of pictures following regulation was similar to the watch condition, and there was no difference in memory performance between the 2 regulation strategies for both groups. These findings do not support the proposal that the type of strategy used explains preserved emotion regulation ability in older adults. Coupled with the lack of memory costs following regulation, these data instead are more consistent with the suggestion that older adults may retain emotion regulation capacity partly because they exhibit less facial reactivity to begin with. (PsycINFO Database Record PMID:26691303

  19. Perspective on fossil power plant layup and reactivation

    SciTech Connect

    Tsou, J.L.

    1996-12-31

    In recent years, many utilities have developed excess generation capacity problems during period of low system load growth, particularly with new generation units coming on-line. System load studies may indicate that the situation is temporary and higher generation capacity will be needed in the near future. The objective of layup is to prevent component deterioration during the long shut down periods. This paper discusses equipment preservation practices in use by the electric utility industry and the advantages/disadvantages of various layup methods. Other issues related to plant layup and reactivation are also presented.

  20. 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.

  1. 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.

  2. 78 FR 63176 - Notice Announcing Workshop; Zero Rate Reactive Power Rate Schedules

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-23

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Notice Announcing Workshop; Zero Rate Reactive Power Rate Schedules Concurrent with this notice, the Commission is issuing an order in Chehalis Power Generating, L.P., Docket...

  3. 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…

  4. 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…

  5. 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.

  6. Analysis of a parallel-arrayed power regulating system

    NASA Technical Reports Server (NTRS)

    Colburn, B. K.; Horton, H. M.; Honnell, M. A.

    1979-01-01

    A power regulation system incorporating n-parallel power supplies employing PWM switching regulators is studied. Analysis of individual unit operation and coupled-system parameter sensitivity is considered from an operations viewpoint. A detailed example is included to illustrate parallel system operation for 18 such units powered by solar-cell banks.

  7. 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.

  8. 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. PMID:26159808

  9. 78 FR 63177 - Order on Voluntary Remand and Clarifying Policy on Filing of Reactive Power Service Rate...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-23

    ... Generation Sources Service (reactive power) to the Bonneville Power Administration (Bonneville or BPA) is a....'' \\5\\ The Commission stated that ``Chehalis has been providing reactive power to BPA pursuant to an... interconnection agreement between Chehalis and BPA was required to be filed prior to May 2005, even though it...

  10. Interpolation Approximation of Voltage Stability Constrained OPF (VSCOPF) for Reactive Power Planning

    SciTech Connect

    Tolbert, Leon M; Zhang, Wenjuan; Li, Fangxing

    2011-01-01

    Reactive power planning (RPP), or Var planning, is to identify the optimal size and location of reactive power sources. In this paper, first, the previous work using least square method to simplify the voltage stability constrained OPF (VSCOPF) model for RPP is presented. Then, this paper presents a new model simplification solution using interpolation. The interpolation approach can be easily applied to a piecewise formulation while preserving the continuity at boundary points, which cannot be easily achieved by previous works like the least square method. The proposed interpolation approach is numerically tested and compared with the least square approach. It is concluded that interpolation is an improved model simplification approach for RPP.

  11. Linguistic Markers of Emotion Regulation and Cardiovascular Reactivity Among Older Caregiving Spouses

    PubMed Central

    Monin, Joan K.; Schulz, Richard; Lemay, Edward P.; Cook, Thomas B.

    2013-01-01

    This study examined linguistic markers of emotion regulation and cardiovascular stress reactivity in spousal caregivers. Fifty-three individuals were audiotaped while they privately disclosed an instance of partner suffering and a typical partner interaction (i.e., a meal together). Systolic blood pressure, diastolic blood pressure, and heart rate (HR) were measured. Linguistic analysis determined emotion and cognitive processing word use. Results revealed that using more positive emotion words was associated with lower HR reactivity in each verbal account. Caregivers who used fewer cognitive processing words (e.g., think, realize, because) overall had the highest HR reactivity to talking about the partner’s suffering. These findings have implications for interventions for all caregivers as well as distinguishing more resilient caregivers from those who may be at a higher risk for caregiver burden. PMID:22369634

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

    DOE PAGESBeta

    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 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

  13. 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.

  14. Regulated dc-to-dc converter features low power drain

    NASA Technical Reports Server (NTRS)

    Thornwall, J.

    1968-01-01

    A regulated dc-to-dc converter requires negligible standby power for the operation of critical electronic equipment. The main operating circuitry consumes power intermittently according to load conditions, rather than constantly.

  15. 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.

  16. Voltage and Reactive Power Control by Integration of Genetic Algorithm and Tabu Search

    NASA Astrophysics Data System (ADS)

    Aoki, Hidenori; Yamamoto, Kensei; Mizutani, Yoshibumi

    This paper presents on the result of voltage and reactive power control by use of the proposed method. The feature of proposed method is integration of genetic algorithm (GA) and tabu search (TS). This method obtains an excellent fitness at shorter calculation time than GA considering conventional control process. The effectiveness of this method is shown by a practicable 15-bus system.

  17. 77 FR 21555 - Reactive Power Resources; Supplemental Notice of Technical Conference

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-10

    ... Interconnection Studies. This panel will discuss: Methods used to determine the reactive power requirements for a... Robert Jenkins, Director--Utility Interconnection, First Solar Kris Zadlo, Vice President, Invenergy..., Director--Utility Interconnection, First Solar Michael Jacobs, Director Market and Regulatory...

  18. 78 FR 72673 - Zero Rate Reactive Power Rate Schedules; Notice of Staff Workshop

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-03

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Zero Rate Reactive Power Rate Schedules; Notice of Staff Workshop This.... to 4 p.m. at the Federal Energy Regulatory Commission, 888 First Street NE., Washington, DC...

  19. 78 FR 75562 - Zero Rate Reactive Power Rate Schedules; Notice of Staff Workshop

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-12

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Zero Rate Reactive Power Rate Schedules; Notice of Staff Workshop This... on December 11, 2013 from 1:30 p.m. to 4 p.m. at the Federal Energy Regulatory Commission, 888...

  20. Real Power and Reactive Power Control of a Three-Phase Single-Stage-PV System and PV voltage Stability

    SciTech Connect

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

    2012-01-01

    Grid-connected photovoltaic (PV) systems with power electronic interfaces can provide both real and reactive power to meet power system needs with appropriate control algorithms. This paper presents the control algorithm design for a three-phase single-stage grid-connected PV inverter to achieve either maximum power point tracking (MPPT) or a certain amount of real power injection, as well as the voltage/var control. The switching between MPPT control mode and a certain amount of real power control mode is automatic and seamless. Without the DC-to-DC booster stage, PV DC voltage stability is an important issue in the control design especially when the PV inverter is operating at maximum power point (MPP) with voltage/var control. The PV DC voltage collapse phenomenon and its reason are discussed. The method based on dynamic correction of the PV inverter output is proposed to ensure PV DC voltage stability. Simulation results of the single-stage PV system during system disturbances and fast solar irradiation changes confirm that the proposed control algorithm for single-stage PV inverters can provide appropriate real and reactive power services and ensure PV DC voltage stability during dynamic system operation and atmospheric conditions.

  1. Reactive Oxygen Species in the Regulation of Stomatal Movements1[OPEN

    PubMed Central

    Sierla, Maija; Waszczak, Cezary; Vahisalu, Triin

    2016-01-01

    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 Ca2+ 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. PMID:27208297

  2. 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. PMID:25253719

  3. A parametric model for reactive high-power impulse magnetron sputtering of films

    NASA Astrophysics Data System (ADS)

    Kozák, Tomáš; Vlček, Jaroslav

    2016-02-01

    We present a time-dependent parametric model for reactive HiPIMS deposition of films. Specific features of HiPIMS discharges and a possible increase in the density of the reactive gas in front of the reactive gas inlets placed between the target and the substrate are considered in the model. The model makes it possible to calculate the compound fractions in two target layers and in one substrate layer, and the deposition rate of films at fixed partial pressures of the reactive and inert gas. A simplified relation for the deposition rate of films prepared using a reactive HiPIMS is presented. We used the model to simulate controlled reactive HiPIMS depositions of stoichiometric \\text{Zr}{{\\text{O}}2} films, which were recently carried out in our laboratories with two different configurations of the {{\\text{O}}2} inlets in front of the sputtered target. The repetition frequency was 500 Hz at the deposition-averaged target power densities of 5 Wcm-2and 50 Wcm-2 with a pulse-averaged target power density up to 2 kWcm-2. The pulse durations were 50 μs and 200 μs. Our model calculations show that the to-substrate {{\\text{O}}2} inlet provides systematically lower compound fractions in the target surface layer and higher compound fractions in the substrate surface layer, compared with the to-target {{\\text{O}}2} inlet. The low compound fractions in the target surface layer (being approximately 10% at the deposition-averaged target power density of 50 Wcm-2 and the pulse duration of 200 μs) result in high deposition rates of the films produced, which are in agreement with experimental values.

  4. Reactive and proactive aggression: Differential links with emotion regulation difficulties, maternal criticism in adolescence.

    PubMed

    Skripkauskaite, Simona; Hawk, Skyler T; Branje, Susan J T; Koot, Hans M; van Lier, Pol A C; Meeus, Wim

    2015-05-01

    Proactive and reactive functions of aggression are thought to manifest through different familial and emotional processes, even though they often co-occur. We investigated direct and indirect pathways through which maternal criticism and emotion regulation (ER) difficulties relate to reactive and proactive aggression in adolescence. Further, we examined how maternal criticism and emotion dysregulation interrelate, both concurrently and over time. Participants were 482 Dutch adolescents (M = 15.03, SD = 0.45, 57% boys) who self-reported on their ER difficulties, perceived maternal criticism, and reactive/proactive aggression. Cross-lagged panel modeling across four annual measurements revealed direct bidirectional links over time between maternal criticism and emotion dysregulation. Positive links over time from maternal criticism to proactive (but not reactive) aggression were also present. Emotion dysregulation and proactive aggression were linked only indirectly via maternal criticism. Gender did not significantly moderate these links. By revealing differential developmental pathways involving adolescents' ER and maternal criticism, the present study offers support for the dual function model of aggression. Aggr. Behav. 41:214-226, 2015. © 2015 Wiley Periodicals, Inc. PMID:25735840

  5. Redox signaling regulated by an electrophilic cyclic nucleotide and reactive cysteine persulfides.

    PubMed

    Fujii, Shigemoto; Sawa, Tomohiro; Nishida, Motohiro; Ihara, Hideshi; Ida, Tomoaki; Motohashi, Hozumi; Akaike, Takaaki

    2016-04-01

    Reactive oxygen (oxidant) and free radical species are known to cause nonspecific damage of various biological molecules. The oxidant toxicology is developing an emerging concept of the physiological functions of reactive oxygen species in cell signaling regulation. Redox signaling is precisely modulated by endogenous electrophilic substances that are generated from reactive oxygen species during cellular oxidative stress responses. Among diverse electrophilic molecular species that are endogenously generated, 8-nitroguanosine 3',5'-cyclic monophosphate (8-nitro-cGMP) is a unique second messenger whose formation, signaling, and metabolism in cells was recently clarified. Most important, our current studies revealed that reactive cysteine persulfides that are formed abundantly in cells are critically involved in the metabolism of 8-nitro-cGMP. Modern redox biology involves frontiers of cell research and stem cell research; medical and clinical investigations of infections, cancer, metabolic syndrome, aging, and neurodegenerative diseases; and other fields. 8-Nitro-cGMP-mediated signaling and metabolism in cells may therefore be potential targets for drug development, which may lead to discovery of new therapeutic agents for many diseases. PMID:27095231

  6. 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.

  7. 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

  8. 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.

  9. Maternal posttraumatic stress symptoms and infant emotional reactivity and emotion regulation.

    PubMed

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

    2011-12-01

    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

  10. Regulation of power pools and system operators: An international comparison

    SciTech Connect

    Barker, J. Jr.; Tenenbaum, B.; Woolf, F.

    1997-12-31

    This paper focuses on the governance and regulation of power pools outside the United States. The current governance and regulatory arrangements for four power pools, as developed in pool documents and government regulations and laws, are compared and contrasted. The power pools analyzed are located in England and Wales, Australia, Canada, and Scandinavia. Topics discussed in relation to these pools are the effects of structure on governance, how each pool has dealt with a number of basic governance decisions, how the pools monitor the markets, ways in which regulators and other institutions control pools, and self-governance issues.

  11. Chromatin structure regulates human cytomegalovirus gene expression during latency, reactivation and lytic infection.

    PubMed

    Sinclair, John

    2010-01-01

    Infection of cells with human cytomegalovirus (HCMV) has two potential outcomes. For instance, infection of fibroblasts results in extensive viral gene expression, viral DNA replication and release of progeny virus. In contrast, in undifferentiated myeloid cells, the lytic transcription programme of HCMV is effectively suppressed and cells undergo latent infection. It is now accepted that the suppression of viral lytic gene expression observed during latency in myeloid cells is a result of the inability of undifferentiated cell types to support robust viral immediate early (IE) gene expression--crucial genes responsible for driving the lytic cycle. The repression of IE gene expression in undifferentiated myeloid cells, at least in part, results from specific post-translational modifications of histones associated with the viral major immediate early promoter (MIEP). In cells of the early myeloid lineage, the histone modifications present on the MIEP impart on it a repressive chromatin structure preventing transcriptional activity. Reactivation of HCMV lytic infection is correlated to changes in histone modifications around the MIEP resulting in a chromatin structure conducive to transcriptional activity. These changes are intimately linked with the differentiation of myeloid cells - a phenomenon known to reactivate latent virus in vivo. Chromatin structure of the viral MIEP, therefore, plays a crucial role in latency and reactivation of this persistent human herpesvirus. Whether chromatin-mediated regulation of viral lytic gene expression also occurs, is only beginning to be addressed. However, recent work suggests that all classes of lytic HCMV promoters are subjected to regulation by post-translational modification of their associated histones throughout the time course of infection. Incoming viral genomes appear to be the targets of intrinsic cellular defence mechanisms which attempt to silence viral gene expression through chromatinisation. Viral functions

  12. Technology and application options for future battery power regulation

    SciTech Connect

    Hurwitch, J.W.; Carpenter, C.A. )

    1991-03-01

    Traditionally, utilities have been interested in battery storage as an option to supply peak power through load leveling. Recently, other benefits of battery storage have been identified which potentially have equal or greater value to electric utilities. These benefits are power regulation functions including area regulation, area protection, spinning reserve, power factor correction, thermal unit minimum loading, and the ability to absorb qualifying facilities. Lead-acid batteries similar to those manufactured for automotive and industrial uses are currently being marketed for utility applications. Compared to the traditional fooded-cell battery that regulates routine watering and maintenance, valve-regulated lead-acid (VRLA) batteries can meet many of the requirements or power regulation at significantly lower operating and maintenance costs. This paper presents an overview of future battery storage applications and technologies. Trends in the utility industry and the future role of battery storage will be addressed with an emphasis on power regulation options. Discussions on battery storage for specific power regulation applications are presented as well as the status of advanced battery development in Europe, Japan, and the United States.

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

    PubMed Central

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

    2016-01-01

    Neuronal communication imposes a heavy metabolic burden in maintaining ionic gradients essential for action potential firing and synaptic signaling. Although cellular metabolism is known to regulate excitatory neurotransmission, it is still unclear whether the brain’s energy supply affects inhibitory signaling. 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 identifies mROS as a putative homeostatic signaling molecule coupling cellular metabolism to the strength of inhibitory transmission. PMID:24430741

  14. 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.

  15. Simple constant-current-regulated power supply

    NASA Technical Reports Server (NTRS)

    Priebe, D. H. E.; Sturman, J. C.

    1977-01-01

    Supply incorporates soft-start circuit that slowly ramps current up to set point at turn-on. Supply consists of full-wave rectifier, regulating pass transistor, current feedback circuit, and quad single-supply operational-amplifier circuit providing control. Technique is applicable to any system requiring constant dc current, such as vacuum tube equipment, heaters, or battery charges; it has been used to supply constant current for instrument calibration.

  16. TLBO based Voltage Stable Environment Friendly Economic Dispatch Considering Real and Reactive Power Constraints

    NASA Astrophysics Data System (ADS)

    Verma, H. K.; Mafidar, P.

    2013-09-01

    In view of growing concern towards environment, power system engineers are forced to generate quality green energy. Hence the economic dispatch (ED) aims at the power generation to meet the load demand at minimum fuel cost with environmental and voltage constraints along with essential constraints on real and reactive power. The emission control which reduces the negative impact on environment is achieved by including the additional constraints in ED problem. Presently, the power system mostly operates near its stability limits, therefore with increased demand the system faces voltage problem. The bus voltages are brought within limit in the present work by placement of static var compensator (SVC) at weak bus which is identified from bus participation factor. The optimal size of SVC is determined by univariate search method. This paper presents the use of Teaching Learning based Optimization (TLBO) algorithm for voltage stable environment friendly ED problem with real and reactive power constraints. The computational effectiveness of TLBO is established through test results over particle swarm optimization (PSO) and Big Bang-Big Crunch (BB-BC) algorithms for the ED problem.

  17. 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…

  18. Electricity distribution network power quality regulation

    NASA Astrophysics Data System (ADS)

    Lopez Sanchez, Jose Maria

    The regulation of the electricity distribution utilities has evolved to a scenario based on competition and cost-effectiveness. This cost reduction may affect the quality performance. A quality regulatory proposal based on yardstick competition is presented in this Ph.D. thesis. The proposal focuses on the continuity of supply in the electricity distribution networks. The competition is against objective values of the selected zonal quality indices that are computed using a probabilistic model that takes into account the historical behavior of the distribution network and considers the quality indices as random variables. A monitoring scheme has been developed to obtain the basic reliability indices from the rough data. A methodology to segment the supplied area is proposed. The implementation plan of the regulatory proposal and the incentive/penalty scheme to encourage utilities to improve their quality indices, are also presented. An implementation study case of the scheme is shown. The conceptual framework of this proposal and the different regulations of the continuity of supply of several countries are also reviewed in detail.

  19. 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.

  20. Modeling for V—O2 reactive sputtering process using a pulsed power supply

    NASA Astrophysics Data System (ADS)

    Wang, Tao; Yu, He; Dong, Xiang; Jiang, Ya-Dong; Chen, Chao; Wu, Ro-Land

    2014-08-01

    In this article, we present a time-dependent model that enables us to describe the dynamic behavior of pulsed DC reactive sputtering and predict the film compositions of VOx prepared by this process. In this modeling, the average current J is replaced by a new parameter of Jeff. Meanwhile, the four species states of V, V2O3, VO2, and V2O5 in the vanadium oxide films are taken into consideration. Based on this work, the influences of the oxygen gas supply and the pulsed power parameters including the duty cycle and frequency on film compositions are discussed. The model suggests that the time to reach process equilibrium may vary substantially depending on these parameters. It is also indicated that the compositions of VOx films are quite sensitive to both the reactive gas supply and the duty cycle when the power supply works in pulse mode. The ‘steady-state’ balance values obtained by these simulations show excellent agreement with the experimental data, which indicates that the experimentally obtained dynamic behavior of the film composition can be explained by this time-dependent modeling for pulsed DC reactive sputtering process. Moreover, the computer simulation results indicate that the curves will essentially yield oscillations around the average value of the film compositions with lower pulse frequency.

  1. 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.

  2. 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

  3. State regulation of nuclear power and national energy policy

    SciTech Connect

    Moeller, J.W.

    1992-12-31

    In April 1983 and January 1984, the United States Supreme Court rendered two decisions that redefined the metes and bounds of federal preemption of commercial nuclear power plant regulation. In Pacific Gas & Electric Co. v. State Energy Resources Conservation and Development Commission (PG&E), the court decided that the Atomic Energy Act of 1954, as amended (the Act), did not preempt a California state law that established a moratorium on commercial nuclear power plant construction. In Silkwood v. Kerr-McGee Corporation, the Court also decided that the Act did not preempt a claim for damages under state tort law for radiological injuries suffered in a nuclear fuel facility regulated by the United States Nuclear Regulatory Commission (NRC). The two decisions redefined the extent of federal preemption, under the Act and other federal law, of nuclear plant regulation as well as the extend of state regulation of nuclear plants. In the eight years since PG&E and Silkwood, numerous other developments have eroded further the breadth of federal preemption of commercial nuclear power plant regulation. This Article explores the developments, since PG&E and Silkwood, that have expanded further the scope of state and local regulation of commercial nuclear power plants. Specifically, the Article first identifies the extent of state and local participation in nuclear power regulation provided by the Act and other federal loan relevant to commercial nuclear power. Second, it discusses in detail the PG&E and Silkwood decisions. The Article also considers the impact of seven specific developments on the legislative implementation of a national energy policy that contemplates a role for nuclear power.

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

    PubMed

    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

  5. 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

  6. Negative feedback regulation of reactive oxygen species on AT1 receptor gene expression

    PubMed Central

    Nickenig, Georg; Strehlow, Kerstin; Bäumer, Anselm T; Baudler, Stefanie; Waßmann, Sven; Sauer, Heinrich; Böhm, Michael

    2000-01-01

    Free radicals as well as the AT1 receptor are involved in the pathogenesis of cardiovascular disease. Both the intracellular mechanisms of AT1 receptor regulation and the effect of free radicals on AT1 receptor expression are currently unknown. This study investigates the role of free radicals in the modulation of AT1 receptor expression and in the angiotensin II-induced AT1 receptor regulation. AT1 receptor mRNA was assessed by Northern blotting and AT1 receptor density by radioligand binding assays, respectively, in vascular smooth muscle cells (VSMC). Free radical release was measured by confocal laser scanning microscopy. AT1 receptor mRNA transcription rate was determined by nuclear run-on assays and AT1 receptor mRNA half-life was measured under transcriptional blockade. Angiotensin II caused a time-dependent decrease of AT1 receptor mRNA expression in rat VSMC in culture (30±6% at 4 h with 100 nM angiotensin II). This was followed by a consistent decrease in AT1 receptor density. Angiotensin II caused release of reactive oxygen species in VSMC which was abolished by preincubation with 100 μM diphenylene iodonium (DPI). DPI inhibited partially the down-regulating effect of angiotensin II on the AT1 receptor. Incubation of VSMC with either hydrogen peroxide or xanthine/xanthine oxidase caused a dose-dependent decrease in AT1 receptor mRNA expression which was not mediated by a decreased rate of transcription but rather through destabilization of AT1 receptor mRNA. Experiments which included preincubation of VSMC with various intracellular inhibitors suggested that free radicals caused AT1 receptor downregulation through activation of p38-MAP kinase and intracellular release of calcium. However, angiotensin II-induced AT1 receptor expression was not inhibited by blockade of p38-MAP kinase activation or intracellular calcium release. Free radicals may at least in part mediate angiotensin II-induced AT1 receptor regulation through direct post

  7. The LIKE SEX FOUR2 regulates root development by modulating reactive oxygen species homeostasis in Arabidopsis

    PubMed Central

    Zhao, Pingzhi; Sokolov, Lubomir N.; Ye, Jian; Tang, Cheng-Yi; Shi, Jisen; Zhen, Yan; Lan, Wenzhi; Hong, Zhi; Qi, Jinliang; Lu, Gui-Hua; Pandey, Girdhar K.; Yang, Yong-Hua

    2016-01-01

    Maintaining reactive oxygen species (ROS) homeostasis plays a central role in plants, and is also critical for plant root development. Threshold levels of ROS act as signals for elongation and differentiation of root cells. The protein phosphatase LIKE SEX FOUR2 (LSF2) has been reported to regulate starch metabolism in Arabidopsis, but little is known about the mechanism how LSF2 affect ROS homeostasis. Here, we identified that LSF2 function as a component modulating ROS homeostasis in response to oxidative stress and, thus regulate root development. Compared with wild type Arabidopsis, lsf2-1 mutant exhibited reduced rates of superoxide generation and higher levels of hydrogen peroxide upon oxidative stress treatments. The activities of several antioxidant enzymes, including superoxide dismutase, catalase, and ascorbate peroxidase, were also affected in lsf2-1 mutant under these oxidative stress conditions. Consequently, lsf2-1 mutant exhibited the reduced root growth but less inhibition of root hair formation compared to wild type Arabidopsis plants. Importantly, protein phosphatase LSF2 interacted with mitogen-activated protein kinase 8 (MPK8), a known component of ROS homeostasis pathways in the cytoplasm. These findings indicated the novel function of LSF2 that controls ROS homeostasis to regulate root development. PMID:27349915

  8. Interleukin-6-dependent and -independent regulation of the human C-reactive protein gene.

    PubMed Central

    Weinhold, B; Rüther, U

    1997-01-01

    We have investigated the function of different mediators of the regulation of the human C-reactive protein (hCRP) gene in transgenic mice. hCRP was induced by lipopolysaccharide and wounding in interleukin-6 (IL-6) +/+ mice, but not in IL-6 -/- mice. This finding suggested that IL-6 is necessary for the induction of hCRP. However, injection of IL-6 did not induce the hCRP gene. Thus, the induction of hCRP by IL-6 seems to require an additional cofactor. Therefore, we screened different cytokines for their activity in IL-6 +/+ and IL-6 -/- mice. Surprisingly, interleukin-1beta, as well as oncostatin M or leukaemia inhibitory factor, led to an induction of hCRP in both genetic backgrounds. These results indicate an IL-6-dependent and -independent regulation of hCRP. These hCRP transgenic mice therefore represent a novel model system for defining the cytokine network involved in the regulation of acute-phase genes during the course of inflammation. PMID:9359411

  9. The LIKE SEX FOUR2 regulates root development by modulating reactive oxygen species homeostasis in Arabidopsis.

    PubMed

    Zhao, Pingzhi; Sokolov, Lubomir N; Ye, Jian; Tang, Cheng-Yi; Shi, Jisen; Zhen, Yan; Lan, Wenzhi; Hong, Zhi; Qi, Jinliang; Lu, Gui-Hua; Pandey, Girdhar K; Yang, Yong-Hua

    2016-01-01

    Maintaining reactive oxygen species (ROS) homeostasis plays a central role in plants, and is also critical for plant root development. Threshold levels of ROS act as signals for elongation and differentiation of root cells. The protein phosphatase LIKE SEX FOUR2 (LSF2) has been reported to regulate starch metabolism in Arabidopsis, but little is known about the mechanism how LSF2 affect ROS homeostasis. Here, we identified that LSF2 function as a component modulating ROS homeostasis in response to oxidative stress and, thus regulate root development. Compared with wild type Arabidopsis, lsf2-1 mutant exhibited reduced rates of superoxide generation and higher levels of hydrogen peroxide upon oxidative stress treatments. The activities of several antioxidant enzymes, including superoxide dismutase, catalase, and ascorbate peroxidase, were also affected in lsf2-1 mutant under these oxidative stress conditions. Consequently, lsf2-1 mutant exhibited the reduced root growth but less inhibition of root hair formation compared to wild type Arabidopsis plants. Importantly, protein phosphatase LSF2 interacted with mitogen-activated protein kinase 8 (MPK8), a known component of ROS homeostasis pathways in the cytoplasm. These findings indicated the novel function of LSF2 that controls ROS homeostasis to regulate root development. PMID:27349915

  10. Stress regulation and cognitive control: evidence relating cortisol reactivity and neural responses to errors.

    PubMed

    Compton, Rebecca J; Hofheimer, Julia; Kazinka, Rebecca

    2013-03-01

    In this study, we tested the relationship between error-related signals of cognitive control and cortisol reactivity, investigating the hypothesis of common systems for cognitive and emotional self-regulation. Eighty-three participants completed a Stroop task while electroencephalography (EEG) was recorded. Three error-related indices were derived from the EEG: the error-related negativity (ERN), error positivity (Pe), and error-related alpha suppression (ERAS). Pre- and posttask salivary samples were assayed for cortisol, and cortisol change scores were correlated with the EEG variables. Better error-correct differentiation in the ERN predicted less cortisol increase during the task, whereas greater ERAS predicted greater cortisol increase during the task; the Pe was not correlated with cortisol changes. We concluded that an enhanced ERN, part of an adaptive cognitive control system, predicts successful stress regulation. In contrast, an enhanced ERAS response may reflect error-related arousal that is not adaptive. The results support the concept of overlapping systems for cognitive and emotional self-regulation. PMID:23055094

  11. Reactive oxygen species: physiological roles in the regulation of vascular cells.

    PubMed

    Vara, D; Pula, G

    2014-01-01

    Reactive oxygen species (ROS) are now appreciated to play several important roles in a number of biological processes and regulate cell physiology and function. ROS are a heterogeneous chemical class that includes radicals, such as superoxide ion (O2(•-)), hydroxyl radical (OH(•)) and nitric oxide (NO(•)), and non-radicals, such as hydrogen peroxide (H2O2), singlet oxygen ((1)O2), hypochlorous acid (HOCl), and peroxynitrite (NO3 (-)). In the cardiovascular system, besides playing a critical role in the development and progression of vasculopathies and other important pathologies such as congestive heart failure, atherosclerosis and thrombosis, ROS also regulate physiological processes. Evidence from a wealth of cardiovascular research studies suggests that ROS act as second messengers and play an essential role in vascular homeostasis by influencing discrete signal transduction pathways in various systems and cell types. They are produced throughout the vascular system, regulate differentiation and contractility of vascular smooth muscle cells, control vascular endothelial cell proliferation and migration, mediate platelet activation and haemostasis, and significantly contribute to the immune response. Our understanding of ROS chemistry and cell biology has evolved to the point of realizing that different ROS have distinct and important roles in cardiovascular physiology. This review will outline sources, functions and molecular mechanisms of action of different ROS in the cardiovascular system and will describe their emerging role in healthy cardiovascular physiology and homeostasis. PMID:24894168

  12. Stress regulation and cognitive control: evidence relating cortisol reactivity and neural responses to errors

    PubMed Central

    Hofheimer, Julia; Kazinka, Rebecca

    2012-01-01

    In this study, we tested the relationship between error-related signals of cognitive control and cortisol reactivity, investigating the hypothesis of common systems for cognitive and emotional self-regulation. Eighty-three participants completed a Stroop task while electroencephalography (EEG) was recorded. Three error-related indices were derived from the EEG: the error-related negativity (ERN), error positivity (Pe), and error-related alpha suppression (ERAS). Pre- and posttask salivary samples were assayed for cortisol, and cortisol change scores were correlated with the EEG variables. Better error–correct differentiation in the ERN predicted less cortisol increase during the task, whereas greater ERAS predicted greater cortisol increase during the task; the Pe was not correlated with cortisol changes. We concluded that an enhanced ERN, part of an adaptive cognitive control system, predicts successful stress regulation. In contrast, an enhanced ERAS response may reflect error-related arousal that is not adaptive. The results support the concept of overlapping systems for cognitive and emotional self-regulation. PMID:23055094

  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. Child temperamental reactivity and self-regulation effects on attentional biases

    PubMed Central

    Susa, Georgiana; Benga, Oana; Pitica, Irina; Miclea, Mircea

    2014-01-01

    This study examined the effects of individual differences in temperamental reactivity (fear) and self-regulation (attentional control) on attentional biases toward threat in a sample of school-aged children (age range was between 9 years 1 month and 13 years 10 months). Attentional biases were assessed with pictorial Dot-probe task, comparing attention allocation toward angry (threat-related) vs. neutral and happy faces. Children also completed self-report temperamental measures of fear and attentional control. We compared attentional bias scores in 4 groups of children: high/low fear and high/low attentional control. Results indicated that, in the case of children with high fear and low attentional control, attention was significantly biased toward angry faces compared with children who had low fear and low attentional control. Findings are discussed in terms of the moderating role of individual differences in attentional control in the context of threat, anxiety-related attentional biases in children. PMID:25202291

  15. Mechanisms that Regulate Production of Reactive Oxygen Species by Cytochrome P450

    SciTech Connect

    Zangar, Richard C.; Davydov, Dmitri R.; Verma, Seema

    2004-09-15

    Mammalian cytochromes P450 (P450) are a family of heme-thiolate enzymes involved in the oxidative metabolism of a variety of endogenous and exogenous lipophilic compounds. Poor coupling of the P450 catalytic cycle results in continuous production of reactive oxygen species (ROS), which affect signaling pathways and other cellular functions. P450 generation of ROS is tightly controlled by regulation of gene transcription, as well as by modulation of interactions between protein constituents of the monooxygenase that affects its activity, coupling and stability. Malfunction of these mechanisms may result in a burst of ROS production, which can cause lipid peroxidation and oxidative stress. In turn, oxidative stress downregulates P450 levels by a variety of feedback mechanisms. This review provides an overview of recent advances in our understanding of these feedback mechanisms that serve to limit P450 production of ROS. Some of the more likely physiological and cellular effects of P450 generation of ROS are also discussed.

  16. Dietary restriction, cardiac autonomic regulation and stress reactivity in bulimic women.

    PubMed

    Vögele, Claus; Hilbert, Anja; Tuschen-Caffier, Brunna

    2009-08-01

    Recent findings suggest sympathetic inhibition during dietary restriction as opposed to increased sympathetic activity during re-feeding. The present study investigated cardiac autonomic regulation and stress reactivity in relation to biochemical markers of dietary restriction status in women diagnosed with bulimia nervosa. We predicted that bulimic individuals (BN) with a biochemical profile indicating dietary restriction exhibit reduced cardiac sympathetic and/or increased vagal activity. We also hypothesized, that BN with a biochemical profile within a normal range (i.e. currently not dieting or malnourished) would show heart rate variability responses (HRV) and reactivity to mental stress indicating increased sympathetic activation compared with non-eating disordered controls. Seventeen female volunteers diagnosed with bulimia nervosa were categorized according to their serum profile (glucose, pre-albumin, IGF-1, TSH, leptin) into currently fasting versus non-fasting and compared with 16 non-eating disordered controls matched for age and BMI. Spectral components of HRV were calculated on heart rate data from resting and mental stress periods (standardized achievement challenge) using autoregressive analysis. Compared to non-fasting BN and controls, fasting BN showed increased vagal and decreased sympathetic modulation during both resting and recovery periods. Cardiac autonomic regulation was not impaired in response to mental challenge. No differences could be found between non-fasting BN and controls. The results confirm the notion of cardiac sympathetic inhibition and vagal dominance during dietary restriction and suggest the specificity of starvation related biochemical changes for cardiac autonomic control. The results are discussed in terms of the higher incidence in cardiac complications in these patients. PMID:19497332

  17. 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.

  18. Voltage and Reactive Power Control by Parallel Calculation Management using Multi-Point TS and CGA

    NASA Astrophysics Data System (ADS)

    Aoki, Hidenori; Michihata, Masashi; Mizutani, Yoshibumi; Hoshino, Hiroshi

    This paper presents a new approach to optimal voltage and reactive power control based on a genetic algorithm (GA) and a tabu search (TS). To reduce time to calculate the control procedure, the parallel computation using Linux is executed. In order to obtain more effective and optimum parallel computation, the characteristic of the parallel processing algorithm used in the proposed method is to effectively utilize the Master operation of ordinary GA parallel processing. In other words, using the waiting time for transmission from the Slave to execute TS as Master. The effectiveness of the proposed method is demonstrated by practical 118-bus system.

  19. Alkbh8 Regulates Selenocysteine-Protein Expression to Protect against Reactive Oxygen Species Damage

    PubMed Central

    Endres, Lauren; Dziergowska, Agnieszka; Małkiewicz, Andrzej; Melendez, J. Andres; Dedon, Peter C.; Begley, Thomas J.

    2015-01-01

    Environmental and metabolic sources of reactive oxygen species (ROS) can damage DNA, proteins and lipids to promote disease. Regulation of gene expression can prevent this damage and can include increased transcription, translation and post translational modification. Cellular responses to ROS play important roles in disease prevention, with deficiencies linked to cancer, neurodegeneration and ageing. Here we detail basal and damage-induced translational regulation of a group of oxidative-stress response enzymes by the tRNA methyltransferase Alkbh8. Using a new gene targeted knockout mouse cell system, we show that Alkbh8-/- embryonic fibroblasts (MEFs) display elevated ROS levels, increased DNA and lipid damage and hallmarks of cellular stress. We demonstrate that Alkbh8 is induced in response to ROS and is required for the efficient expression of selenocysteine-containing ROS detoxification enzymes belonging to the glutathione peroxidase (Gpx1, Gpx3, Gpx6 and likely Gpx4) and thioredoxin reductase (TrxR1) families. We also show that, in response to oxidative stress, the tRNA modification 5-methoxycarbonylmethyl-2′-O-methyluridine (mcm5Um) increases in normal MEFs to drive the expression of ROS detoxification enzymes, with this damage-induced reprogramming of tRNA and stop-codon recoding corrupted in Alkbh8-/- MEFS. These studies define Alkbh8 and tRNA modifications as central regulators of cellular oxidative stress responses in mammalian systems. In addition they highlight a new animal model for use in environmental and cancer studies and link translational regulation to the prevention of DNA and lipid damage. PMID:26147969

  20. FOXO3a regulates reactive oxygen metabolism by inhibiting mitochondrial gene expression

    PubMed Central

    Ferber, E C; Peck, B; Delpuech, O; Bell, G P; East, P; Schulze, A

    2012-01-01

    Forkhead transcription factors of the O class (FOXOs) are important targets of the phosphatidylinositol 3-kinase/Akt pathway, and are key regulators of the cell cycle, apoptosis and response to oxidative stress. FOXOs have been shown to have tumour suppressor function and are important for stem cell maintenance. We have performed a detailed analysis of the transcriptional programme induced in response to Forkhead-box protein O3a (FOXO3a) activation. We observed that FOXO3a activation results in the repression of a large number of nuclear-encoded genes with mitochondrial function. Repression of these genes was mediated by FOXO3a-dependent inhibition of c-Myc. FOXO3a activation also caused a reduction in mitochondrial DNA copy number, expression of mitochondrial proteins, respiratory complexes and mitochondrial respiratory activity. FOXO3a has been previously implicated in the detoxification of reactive oxygen species (ROS) through induction of manganese-containing superoxide dismutase (SOD2). We observed that reduction in ROS levels following FOXO3a activation was independent of SOD2, but required c-Myc inhibition. Hypoxia increases ROS production from the mitochondria, which is required for stabilisation of the hypoxia-inducible factor-1α (HIF-1α). FOXO3a activation blocked the hypoxia-dependent increase in ROS and prevented HIF-1α stabilisation. Our data suggest that FOXO factors regulate mitochondrial activity through inhibition of c-Myc function and alter the hypoxia response. PMID:22139133

  1. Neuroprotection by Polynitrogen Manganese Complexes: Regulation of Reactive Oxygen Species-Related Pathways.

    PubMed

    Chen, Chunxia; Cao, Jing; Ma, Xiaoyan; Wang, Xiaobo; Chen, Qiuyun; Yan, Shihai; Zhao, Ningwei; Geng, Zhirong; Wang, Zhilin

    2016-01-01

    Cell death in the central nervous system causes neurologic diseases, in which reactive oxygen species (ROS) play a critical role by either inducing cellular oxidative stress or by increasing the cell tolerance against insult. Neurologic diseases may potentially be treated by regulating ROS levels in a certain range with small molecules. We studied preconditioning with two polynitrogen manganese complexes (1 and 2) to regulate intracellular ROS levels in the protection of both the differentiated rat pheochromocytoma cell line (PC12 cells) and neurons against H2O2-induced apoptosis. Pre-treatment with the two complexes attenuated the cell apoptosis caused by H2O2. And the ROS-related neuroprotective mechanisms were explored. Both complexes activate the hypoxia inducible factor-related pathways and increase the cell adaptation to oxidative stress. Pre-treatment with complex 1 eliminated intracellular ROS, which also activated antioxidase system, while short-term incubation of complex 2, generated low levels of ROS leading to cell survival. PMID:26857964

  2. 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. PMID:27208225

  3. FOXO3a regulates reactive oxygen metabolism by inhibiting mitochondrial gene expression.

    PubMed

    Ferber, E C; Peck, B; Delpuech, O; Bell, G P; East, P; Schulze, A

    2012-06-01

    Forkhead transcription factors of the O class (FOXOs) are important targets of the phosphatidylinositol 3-kinase/Akt pathway, and are key regulators of the cell cycle, apoptosis and response to oxidative stress. FOXOs have been shown to have tumour suppressor function and are important for stem cell maintenance. We have performed a detailed analysis of the transcriptional programme induced in response to Forkhead-box protein O3a (FOXO3a) activation. We observed that FOXO3a activation results in the repression of a large number of nuclear-encoded genes with mitochondrial function. Repression of these genes was mediated by FOXO3a-dependent inhibition of c-Myc. FOXO3a activation also caused a reduction in mitochondrial DNA copy number, expression of mitochondrial proteins, respiratory complexes and mitochondrial respiratory activity. FOXO3a has been previously implicated in the detoxification of reactive oxygen species (ROS) through induction of manganese-containing superoxide dismutase (SOD2). We observed that reduction in ROS levels following FOXO3a activation was independent of SOD2, but required c-Myc inhibition. Hypoxia increases ROS production from the mitochondria, which is required for stabilisation of the hypoxia-inducible factor-1α (HIF-1α). FOXO3a activation blocked the hypoxia-dependent increase in ROS and prevented HIF-1α stabilisation. Our data suggest that FOXO factors regulate mitochondrial activity through inhibition of c-Myc function and alter the hypoxia response. PMID:22139133

  4. 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

  5. Neuroprotection by Polynitrogen Manganese Complexes: Regulation of Reactive Oxygen Species-Related Pathways

    PubMed Central

    Chen, Chunxia; Cao, Jing; Ma, Xiaoyan; Wang, Xiaobo; Chen, Qiuyun; Yan, Shihai; Zhao, Ningwei; Geng, Zhirong; Wang, Zhilin

    2016-01-01

    Cell death in the central nervous system causes neurologic diseases, in which reactive oxygen species (ROS) play a critical role by either inducing cellular oxidative stress or by increasing the cell tolerance against insult. Neurologic diseases may potentially be treated by regulating ROS levels in a certain range with small molecules. We studied preconditioning with two polynitrogen manganese complexes (1 and 2) to regulate intracellular ROS levels in the protection of both the differentiated rat pheochromocytoma cell line (PC12 cells) and neurons against H2O2-induced apoptosis. Pre-treatment with the two complexes attenuated the cell apoptosis caused by H2O2. And the ROS-related neuroprotective mechanisms were explored. Both complexes activate the hypoxia inducible factor-related pathways and increase the cell adaptation to oxidative stress. Pre-treatment with complex 1 eliminated intracellular ROS, which also activated antioxidase system, while short-term incubation of complex 2, generated low levels of ROS leading to cell survival. PMID:26857964

  6. Ethylene Response Factor 6 Is a Regulator of Reactive Oxygen Species Signaling in Arabidopsis

    PubMed Central

    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. PMID:23940555

  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. 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.

  9. 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.

  10. Reactive oxygen species regulate alkaloid metabolism in undifferentiated N. tabacum cells.

    PubMed

    Sachan, Nita; Rogers, Dennis T; Yun, Kil-Young; Littleton, John M; Falcone, Deane L

    2010-05-01

    Plants produce an immense number of natural products and undifferentiated cells from various plant tissues have long been considered an ideal source for their synthesis. However, undifferentiated plant cells often either lose their biosynthetic capacity over time or exhibit immediate repression of the required pathways once dedifferentiated. In this study, freshly prepared callus tissue was employed to further investigate the regulation of a natural product pathway in undifferentiated tobacco cells. Putrescine N-methyltransferase (PMT) is a pathway-specific enzyme required in nicotinic alkaloid production in Nicotiana species. Callus derived from transgenic Nicotiana tabacum plants harboring PMT promoter-GUS fusions were used to study factors that influence PMT expression. Under normal callus growth conditions in the presence of light and auxin, PMT promoter activity was strongly repressed. Conversely, dark conditions and the absence of auxin were found to upregulate PMT promoter activity, with light being dominant to the repressive effects of auxin. Since reactive oxygen species (ROS) are known by-products of photosynthesis and have been implicated in signaling, their involvement was investigated in transgenic callus by treatment with the ROS scavenger, dimethylthiourea, or catalase. Under highly repressive conditions for alkaloid synthesis, including normal culture conditions in the light, both ROS scavengers resulted in significant induction of PMT promoter activity. Moreover, treatment of callus with catalase resulted in the upregulation of PMT promoter activity and alkaloid accumulation in this tissue. These results suggest that ROS impact the regulation of the alkaloid pathway in undifferentiated cells and have implications for regulation of the pathway in other plant tissues. PMID:20217418

  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. Reactive oxygen species regulate Smac mimetic/TNFα-induced necroptotic signaling and cell death.

    PubMed

    Schenk, B; Fulda, S

    2015-11-19

    Necroptosis represents a key programmed cell death pathway involved in various physiological and pathophysiological conditions. However, the role of reactive oxygen species (ROS) in necroptotic signaling has remained unclear. In the present study, we identify ROS as critical regulators of BV6/tumor necrosis factor-α (TNFα)-induced necroptotic signaling and cell death. We show that BV6/TNFα-induced cell death depends on ROS production, as several ROS scavengers such as butylated hydroxyanisole, N-acetylcysteine, α-tocopherol and ethyl pyruvate significantly rescue cell death. Before cell death, BV6/TNFα-stimulated ROS generation promotes stabilization of the receptor-interacting protein kinase 1 (RIP1)/RIP3 necrosome complex via a potential positive feedback loop, as on the one hand radical scavengers attenuate RIP1/RIP3 necrosome assembly and phosphorylation of mixed lineage kinase domain like (MLKL), but on the other hand silencing of RIP1 or RIP3 reduces ROS production. Although MLKL knockdown effectively decreases BV6/TNFα-induced cell death, it does not affect RIP1/RIP3 interaction and only partly reduces ROS generation. Moreover, the deubiquitinase cylindromatosis (CYLD) promotes BV6/TNFα-induced ROS generation and necrosome assembly even in the presence of BV6, as CYLD silencing attenuates these events. Genetic silencing of phosphoglycerate mutase 5 or dynamin-related protein 1 (Drp1) fails to protect against BV6/TNFα-induced cell death. By demonstrating that ROS are involved in regulating BV6/TNFα-induced necroptotic signaling, our study provides new insights into redox regulation of necroptosis. PMID:25867066

  13. Effects of V2G Reactive Power Compensation on the Component Selection in an EV or PHEV Bidirectional Charger

    SciTech Connect

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

    2010-01-01

    Electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs) are becoming a part of the electric grid day by day. Chargers for these vehicles have the ability to make this interaction better for the consumer and for the grid. Vehicle to grid (V2G) power transfer has been under research for more than a decade because of the large energy reserve of an electric vehicle battery and the potential of thousands of these connected to the grid. Rather than discharging the vehicle batteries, reactive power compensation in particular is beneficial for both consumers and for the utility. However, certain adverse effects or requirements of reactive power transfer should be defined before a design stage. To understand the dynamics of this operation, this study investigates the effect of reactive power transfer on the charger system components, especially on the dc-link capacitor and the battery.

  14. Improving Power-Supply Regulation for Pulsed Loads

    NASA Technical Reports Server (NTRS)

    Gulick, C. R.; Chan, R. B.

    1982-01-01

    Power supply voltage-regulator circuit speeds up response to sudden load changes. As load increases, additional feedback path is enabled. Path bypasses and provides faster loop response than normal feedback path. Steady-state instability due to faster loop response avoided by progressively disabling bypass loop and allowing normal feedback path to take over.

  15. Estimation of reactive power export and import capability for non-utility generators

    SciTech Connect

    Nolan, G.J.; Winge, D.E.; Khalafalla, E.B.; Swartley, B.S.; Arnold, E.H.

    1995-12-31

    Non-utility generators (NUGs) are typically required by their electric power sales agreement to have the capability to supply power to the purchasing utility near unity power factor. With the advent of large combustion turbine generators, many NUGs are simple or combined cycle facilities with generating capacities in excess of low megawatts. Utilities are recognizing that these large NUG facilities can be significant contributors to the reactive power (megavars-Mvars) flow needed to support system requirements and transmission level grid voltages. NUGs are now being dispatched for Mvar export and import activities to meet utility requirements. The ability of a NUG to export or import Mvars is highly dependent on the actual transmission intertie voltage level. Unless plant specific studies are performed, this can be difficult to ascertain for the NUG`s operating and engineering personnel. This paper presents a method, based on system load flow studies, for estimating the capacity of a NUG to export or import Mvars at a given transmission intertie voltage level. It also explores other key variables which determine the ability of a NUG to export or import VARS. This methodology can be used to aid operating personnel at existing facilities or as a guide during the design of a new facility.

  16. 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...

  17. 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.

  18. 75 FR 30812 - Frequency Regulation Compensation in the Organized Wholesale Power Markets; Further Notice...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-02

    ... Organized Wholesale Power Markets, 75 FR 23,759, as supplemented by Supplemental Notice of Technical... Energy Regulatory Commission Frequency Regulation Compensation in the Organized Wholesale Power Markets... of Proposed Rulemaking on Frequency Regulation Compensation in the Organized Wholesale Power...

  19. Antioxidant enzymes regulate reactive oxygen species during pod elongation in Pisum sativum and Brassica chinensis.

    PubMed

    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

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

    PubMed

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

    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

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

    PubMed

    Chen, Xinfeng; Song, Mengjia; Zhang, Bin; Zhang, Yi

    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

  2. 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

  3. WhiB5, a Transcriptional Regulator That Contributes to Mycobacterium tuberculosis Virulence and Reactivation

    PubMed Central

    Casonato, Stefano; Cervantes Sánchez, Axel; Haruki, Hirohito; Rengifo González, Monica; Provvedi, Roberta; Dainese, Elisa; Jaouen, Thomas; Gola, Susanne; Bini, Estela; Vicente, Miguel; Johnsson, Kai; Ghisotti, Daniela; Palù, Giorgio; Hernández-Pando, Rogelio

    2012-01-01

    The proteins belonging to the WhiB superfamily are small global transcriptional regulators typical of actinomycetes. In this paper, we characterize the role of WhiB5, a Mycobacterium tuberculosis protein belonging to this superfamily. A null mutant was constructed in M. tuberculosis H37Rv and was shown to be attenuated during both progressive and chronic mouse infections. Mice infected with the mutant had smaller bacillary burdens in the lungs but a larger inflammatory response, suggesting a role of WhiB5 in immunomodulation. Most interestingly, the whiB5 mutant was not able to resume growth after reactivation from chronic infection, suggesting that WhiB5 controls the expression of genes involved in this process. The mutant was also more sensitive than the wild-type parental strain to S-nitrosoglutathione (GSNO) and was less metabolically active following prolonged starvation, underscoring the importance of GSNO and starvation in development and maintenance of chronic infection. DNA microarray analysis identified 58 genes whose expression is influenced by WhiB5, including sigM, encoding an alternative sigma factor, and genes encoding the constituents of two type VII secretion systems, namely, ESX-2 and ESX-4. PMID:22733573

  4. Reactive oxygen species, abscisic acid and ethylene interact to regulate sunflower seed germination.

    PubMed

    El-Maarouf-Bouteau, Hayat; Sajjad, Yasar; Bazin, Jérémie; Langlade, Nicolas; Cristescu, Simona M; Balzergue, Sandrine; Baudouin, Emmanuel; Bailly, Christophe

    2015-02-01

    Sunflower (Helianthus annuus L.) seed dormancy is regulated by reactive oxygen species (ROS) and can be alleviated by incubating dormant embryos in the presence of methylviologen (MV), a ROS-generating compound. Ethylene alleviates sunflower seed dormancy whereas abscisic acid (ABA) represses germination. The purposes of this study were to identify the molecular basis of ROS effect on seed germination and to investigate their possible relationship with hormone signalling pathways. Ethylene treatment provoked ROS generation in embryonic axis whereas ABA had no effect on their production. The beneficial effect of ethylene on germination was lowered in the presence of antioxidant compounds, and MV suppressed the inhibitory effect of ABA. MV treatment did not alter significantly ethylene nor ABA production during seed imbibition. Microarray analysis showed that MV treatment triggered differential expression of 120 probe sets (59 more abundant and 61 less abundant genes), and most of the identified transcripts were related to cell signalling components. Many transcripts less represented in MV-treated seeds were involved in ABA signalling, thus suggesting an interaction between ROS and ABA signalling pathways at the transcriptional level. Altogether, these results shed new light on the crosstalk between ROS and plant hormones in seed germination. PMID:24811898

  5. Reactive Oxygen Species Regulate Innate But Not Adaptive Inflammation in ZAP70-Mutated SKG Arthritic Mice.

    PubMed

    Guerard, Simon; Holmdahl, Rikard; Wing, Kajsa

    2016-09-01

    Polysaccharides from Saccharomyces cerevisiae can induce arthritis, ileitis, and interstitial pneumonitis in BALB/c ZAP70 (W163C)-mutant (SKG) mice via T helper 17-cell-dependent pathways. However, little is known regarding the factors influencing disease severity. We investigated mannan-induced arthritis in SKG mice and how NADPH oxidase 2-derived reactive oxygen species (ROS) regulate disease. SKG mice were highly susceptible to both IL-17-mediated T-cell-driven arthritis and T-cell-independent acute psoriasis-like dermatitis. In vivo imaging revealed more ROS in joints of arthritic SKG mice compared to wild-type mice, which links ROS and joint inflammation. Still, ROS deficiency in SKG.Ncf1(m1j/m1j) mice greatly increased severity of arthritis and dermatitis, a difference that could not be attributed to increased T-cell activation, thymic selection, or antibody production. However, when ROS production was restored in CD68(+) macrophages, inflammation reverted to baseline, demonstrating a regulatory role of macrophage-derived ROS in autoimmunity. Thus, arthritis in SKG mice is a useful model to study the role of ROS in innate-driven chronic inflammation independently of adaptive immunity. PMID:27427418

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

    DOEpatents

    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.

  7. 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.

  8. 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.

  9. Thermal analysis of a reactive generalized Couette flow of power law fluids between concentric cylindrical pipes

    NASA Astrophysics Data System (ADS)

    Makinde, O. D.

    2014-12-01

    In this paper, the steady generalized axial Couette flow of Ostwald-de Waele power law reactive fluids between concentric cylindrical pipes is investigated. It is assumed that the outer cylinder is stationary and exchanges heat with the ambient surrounding following Newton's law of cooling, while the inner cylinder with isothermal surface is set in motion in the axial direction. The model nonlinear differential equations for the momentum and energy balance are obtained and tackled numerically using the shooting method coupled with the Runge-Kutta-Fehlberg integration technique. The effects of various embedded thermophysical parameters on the velocity and temperature fields including skin friction, Nusselt number and thermal criticality conditions are presented graphically and discussed quantitatively.

  10. Voltage and Reactive Power Control by Integrating Genetic Algorithm and Tabu Search Considering Control Process

    NASA Astrophysics Data System (ADS)

    Yamamoto, Kensei; Aoki, Hidenori; Naoi, Kenji; Mizutani, Yoshibumi

    This paper presents the result of executing the conventional genetic algorithm (GA) and a new method to the voltage and reactive power control (VQC). The conventional GA can give the control process and improve the fitness with the practical control times. And, the method to cancel the limited deviation as early as possible is implemented. Moreover, the method to reduce the control times to the fitness as much as possible is proposed. The proposed method is integrated the tabu search (TS) into the conventional GA. The proposed method generates next generation’s individual with the crossover of the conventional GA and the neighborhood search of the TS. Therefore, the proposed method executes an effective search. As a result, the proposed method can obtain better fitness than the conventional GA in the same calculation times. The effectiveness of the proposed method is demonstrated by practical 15-bus and 118-bus systems.

  11. Deposition of highly textured AlN thin films by reactive high power impulse magnetron sputtering

    SciTech Connect

    Moreira, Milena A.; Törndahl, Tobias; Katardjiev, Ilia; Kubart, Tomas

    2015-03-15

    Aluminum nitride thin films were deposited by reactive high power impulse magnetron sputtering (HiPIMS) and pulsed direct-current on Si (100) and textured Mo substrates, where the same deposition conditions were used for both techniques. The films were characterized by x-ray diffraction and atomic force microscopy. The results show a pronounced improvement in the AlN crystalline texture for all films deposited by HiPIMS on Si. Already at room temperature, the HiPIMS films exhibited a strong preferred (002) orientation and at 400 °C, no contributions from other orientations were detected. Despite the low film thickness of only 200 nm, an ω-scan full width at half maximum value of 5.1° was achieved on Si. The results are attributed to the high ionization of sputtered material achieved in HiPIMS. On textured Mo, there was no significant difference between the deposition techniques.

  12. 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

  13. 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.

  14. Sequential Switching Shunt Maximum Power Point Regulator (S3MPPR)

    NASA Astrophysics Data System (ADS)

    Blanes, J. M.; Garrigos, A.; Carrasco, J. A.; Weinberg, A. H.; Ejea, J. B.; Sanchis, E.; Farreres, A.; Maset, E.; Soto, A.; de la Cruz, F.

    2011-10-01

    This paper presents the implementation of a Sequential Switching Shunt Maximum Power Point Regulator (S3MPPR). The S3MPPR is the evolution of the traditional S3R where the fixed reference, used by the main error amplifier, is replaced by an MPPT voltage reference. With this variation, the system corresponds to a non-regulated bus topology but with the dynamic characteristics of a regulated one and with the ability to track the MPP of the solar array. This work focuses on this topic, studying the best way to implement the S3MPPR in a geostationary telecommunication satellite. In order to validate the proposal, a 1.6 kW prototype has been implemented and many tests have been carried out with the prototype, all of them showing the good behaviour of the converter.

  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. Incentive regulation of investor-owned nuclear power plants by public utility regulators. Revision 1

    SciTech Connect

    McKinney, M.D.; Seely, H.E.; Merritt, C.R.; Baker, D.C.

    1995-04-01

    The US Nuclear Regulatory Commission (NRC) periodically surveys the Federal Energy Regulatory Commission (FERC) and state regulatory commissions that regulate utility owners of nuclear power plants. The NRC is interested in identifying states that have established economic or performance incentive programs applicable to nuclear power plants, how the programs are being implemented, and in determining the financial impact of the programs on the utilities. The NRC interest stems from the fact that such programs have the potential to adversely affect the safety of nuclear power plants. The current report is an update of NUREG/CR-5975, Incentive Regulation of Investor-Owned Nuclear Power Plants by Public Utility Regulators, published in January 1993. The information in this report was obtained from interviews conducted with each state regulatory agency that administers an incentive program and each utility that owns at least 10% of an affected nuclear power plant. The agreements, orders, and settlements that form the basis for each incentive program were reviewed as required. The interviews and supporting documentation form the basis for the individual state reports describing the structure and financial impact of each incentive program.

  17. Impact of hypothalamic reactive oxygen species in the regulation of energy metabolism and food intake

    PubMed Central

    Drougard, Anne; Fournel, Audren; Valet, Philippe; Knauf, Claude

    2015-01-01

    Hypothalamus is a key area involved in the control of metabolism and food intake via the integrations of numerous signals (hormones, neurotransmitters, metabolites) from various origins. These factors modify hypothalamic neurons activity and generate adequate molecular and behavioral responses to control energy balance. In this complex integrative system, a new concept has been developed in recent years, that includes reactive oxygen species (ROS) as a critical player in energy balance. ROS are known to act in many signaling pathways in different peripheral organs, but also in hypothalamus where they regulate food intake and metabolism by acting on different types of neurons, including proopiomelanocortin (POMC) and agouti-related protein (AgRP)/neuropeptide Y (NPY) neurons. Hypothalamic ROS release is under the influence of different factors such as pancreatic and gut hormones, adipokines (leptin, apelin,…), neurotransmitters and nutrients (glucose, lipids,…). The sources of ROS production are multiple including NADPH oxidase, but also the mitochondria which is considered as the main ROS producer in the brain. ROS are considered as signaling molecules, but conversely impairment of this neuronal signaling ROS pathway contributes to alterations of autonomic nervous system and neuroendocrine function, leading to metabolic diseases such as obesity and type 2 diabetes. In this review we focus our attention on factors that are able to modulate hypothalamic ROS release in order to control food intake and energy metabolism, and whose deregulations could participate to the development of pathological conditions. This novel insight reveals an original mechanism in the hypothalamus that controls energy balance and identify hypothalamic ROS signaling as a potential therapeutic strategy to treat metabolic disorders. PMID:25759638

  18. Glutathione modulation during sensitization as well as challenge phase regulates airway reactivity and inflammation in mouse model of allergic asthma.

    PubMed

    Nadeem, Ahmed; Siddiqui, Nahid; Alharbi, Naif O; Alharbi, Mohammad M; Imam, Faisal; Sayed-Ahmed, Mohamed M

    2014-08-01

    Glutathione, being a major intracellular redox regulator has been shown to be implicated in regulation of airway reactivity and inflammation. However, no study so far has investigated the effect of glutathione depletion/repletion during sensitization and challenge phases separately, which could provide an important insight into the pathophysiology of allergic asthma. The aim of the present study was to evaluate the role of glutathione depletion/repletion during sensitization and challenge phases separately in a mouse model of allergic asthma. Buthionine sulphoximine (BSO), an inhibitor of gamma-glutamylcysteine synthetase or N-acetyl cysteine (NAC), a thiol donor were used for depletion or repletion of glutathione levels respectively during both sensitization and challenge phases separately followed by assessment of airway reactivity, inflammation and oxidant-antioxidant balance in allergic mice. Depletion of glutathione with BSO during sensitization as well as challenge phase worsened allergen induced airway reactivity/inflammation and caused greater oxidant-antioxidant imbalance as reflected by increased NADPH oxidase expression/reactive oxygen species (ROS) generation/lipid peroxides formation and decreased total antioxidant capacity. On the other hand, repletion of glutathione pool by NAC during sensitization and challenge phases counteracted allergen induced airway reactivity/inflammation and restored oxidant-antioxidant balance through a decrease in NADPH oxidase expression/ROS generation/lipid peroxides formation and increase in total antioxidant capacity. Taken together, these findings suggest that depletion or repletion of glutathione exacerbates or ameliorates allergic asthma respectively by regulation of airway oxidant-antioxidant balance. This might have implications towards increased predisposition to allergy by glutathione depleting environmental pollutants. PMID:24742380

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Reactive Oxygen Species Modulation of Na/K-ATPase Regulates Fibrosis and Renal Proximal Tubular Sodium Handling

    PubMed Central

    Liu, Jiang; Kennedy, David J.; Yan, Yanling; Shapiro, Joseph I.

    2012-01-01

    The Na/K-ATPase is the primary force regulating renal sodium handling and plays a key role in both ion homeostasis and blood pressure regulation. Recently, cardiotonic steroids (CTS)-mediated Na/K-ATPase signaling has been shown to regulate fibrosis, renal proximal tubule (RPT) sodium reabsorption, and experimental Dahl salt-sensitive hypertension in response to a high-salt diet. Reactive oxygen species (ROS) are an important modulator of nephron ion transport. As there is limited knowledge regarding the role of ROS-mediated fibrosis and RPT sodium reabsorption through the Na/K-ATPase, the focus of this review is to examine the possible role of ROS in the regulation of Na/K-ATPase activity, its signaling, fibrosis, and RPT sodium reabsorption. PMID:22518311

  5. 75 FR 31430 - Frequency Regulation Compensation in the Organized Wholesale Power Markets; Notice Establishing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-03

    ... Markets, 75 FR 23,759, as supplemented by Supplemental Notice of Technical Conference re Frequency... Energy Regulatory Commission Frequency Regulation Compensation in the Organized Wholesale Power Markets... technical conference regarding frequency regulation in the organized wholesale power markets, as...

  6. 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.

  7. 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.

  8. 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

  9. Characterization of combined power plasma jet using AC high voltage and nanosecond pulse for reactive species composition control

    NASA Astrophysics Data System (ADS)

    Takashima, Keisuke; Konishi, Hideaki; Kato, Toshiaki; Kaneko, Toshiro

    2014-10-01

    In the application studies for both bio-medical and agricultural applications, the roles of the reactive oxide and/or nitride species generated in the plasma has been reported as a key to control the effects and ill-effects on the living organism. The correlation between total OH radical exposure from an air atmospheric pressure plasma jet and the sterilization threshold on Botrytis cinerea is presented. With the increase of the OH radical exposure to the Botrytis cinerea, the probability of sterilization is increased. In this study, to resolve the roles of reactive species including OH radicals, a combined power plasma jet using nanosecond pulses and low-frequency sinusoidal AC high voltage (a few kHz) is studied for controlling the composition of the reactive species. The nanosecond pulses are superimposed on the AC voltage which is in synchronization with the AC phase. The undergoing work to characterize the combined power discharge with electric charge and voltage cycle on the plasma jet will also be presented to discuss the discharge characteristics to control the composition of the reactive species.

  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. 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.

  12. High Power Factor Control Regulating Inverter Output Power in IPM Motor Driven by Inverter System without Electrolytic Capacitor

    NASA Astrophysics Data System (ADS)

    Inazuma, Kazuya; Ohishi, Kiyoshi; Haga, Hitoshi; Sazawa, Mataki; Kondo, Seiji

    This paper presents a new high power factor control method for a single-to-three-phase power converter without an electrolytic capacitor. The circuit used in the method consists of a single-phase rectifier, a small film capacitor at DC-link, a voltage-source three-phase inverter, and an IPM motor. The inverter regulates both the velocity of the IPM motor and input current waveform. In order to obtain a power factor of unity, we propose a new control method that regulates the inverter output power. The inverter output power controller is placed between the speed controller and the q-axis current controller. The inverter power is regulated by a PI and repetitive controller. When repetitive control is applied to the inverter power controller, the phase delay of the inverter power controller is quite small. The superior performance of the proposed method is demonstrated by experimental results.

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

    PubMed

    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

  14. 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

  15. Emotional development across adulthood: differential age-related emotional reactivity and emotion regulation in a negative mood induction procedure.

    PubMed

    Kliegel, Matthias; Jäger, Theodor; Phillips, Louise H

    2007-01-01

    The present study examines the hypothesis that older adults might differentially react to a negative versus neutral mood induction procedure than younger adults. The rationale for this expectation was derived from Socioemotional Selectivity Theory (SST), which postulates differential salience of emotional information and ability to regulate emotions across adulthood. The present data support a view of differential age-related effects of negative mood inductions with greater and more heterogeneous emotional reactivity among older adults, who showed a substantially greater decrease in self-rated pleasantness, calmness, and wakefulness than younger adults. Moreover, relative to the younger adults, emotion regulation in terms of mood repair was more effective among the older adults. The age-related mood effects are discussed in terms of SST and have practical implications for the study of emotion and cognition across adulthood. PMID:17503687

  16. 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.

  17. 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…

  18. 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 PAGESBeta

    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 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

  19. 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.

  20. The Anopheles gambiae Oxidation Resistance 1 (OXR1) Gene Regulates Expression of Enzymes That Detoxify Reactive Oxygen Species

    PubMed Central

    Jaramillo-Gutierrez, Giovanna; Molina-Cruz, Alvaro; Kumar, Sanjeev; Barillas-Mury, Carolina

    2010-01-01

    Background OXR1 is an ancient gene, present in all eukaryotes examined so far that confers protection from oxidative stress by an unknown mechanism. The most highly conserved region of the gene is the carboxyl-terminal TLDc domain, which has been shown to be sufficient to prevent oxidative damage. Methodology/Principal Findings OXR1 has a complex genomic structure in the mosquito A. gambiae, and we confirm that multiple splice forms are expressed in adult females. Our studies revealed that OXR1 regulates the basal levels of catalase (CAT) and glutathione peroxidase (Gpx) expression, two enzymes involved in detoxification of hydrogen peroxide, giving new insight into the mechanism of action of OXR1. Gene silencing experiments indicate that the Jun Kinase (JNK) gene acts upstream of OXR1 and also regulates expression of CAT and GPx. Both OXR1 and JNK genes are required for adult female mosquitoes to survive chronic oxidative stress. OXR1 silencing decreases P. berghei oocyst formation. Unexpectedly, JNK silencing has the opposite effect and enhances Plasmodium infection in the mosquito, suggesting that JNK may also mediate some, yet to be defined, antiparasitic response. Conclusion The JNK pathway regulates OXR1 expression and OXR1, in turn, regulates expression of enzymes that detoxify reactive oxygen species (ROS) in Anopheles gambiae. OXR1 silencing decreases Plasmodium infection in the mosquito, while JNK silencing has the opposite effect and enhances infection. PMID:20567517

  1. 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.

  2. Regulation of hypoxia-inducible factor-1a by reactive oxygen species: new developments in an old debate.

    PubMed

    Movafagh, Shahrzad; Crook, Sean; Vo, Kim

    2015-05-01

    Hypoxia-Inducible Factor-1 (HIF-1) has been largely studied for its role in cell survival in hypoxic conditions. The regulation of HIF-1 is a complex process and involves a number of molecules and pathways. Among these mechanisms a direct regulatory role of reactive oxygen species (ROS) on HIF-1 alpha subunit has received a great deal of attention and the existing body of literature includes many contradictory findings. Other intermediates such as nitric oxide (NO), specific microRNAs (miR), and transcriptional and post-translational modification have also been implicated as players in ROS mediated HIF-1a regulation. The focus of this review is to present the past conflicting evidence along with more recent findings in order to relate various aspects of this complex process. Aside from the direct role of ROS on HIF-1a regulation under hypoxia and normoxia, we analyzed the effect of different sources and concentrations of NO and the interplay between superoxide (SO) and NO in this process. We also present findings on transcriptional and translational regulation of HIF-1a via ROS and the interplay with microRNAs in this process. This review further provides insight on ERK and PI3K/AKT signaling as a common mechanism relating several pathways of ROS mediated HIF-1a regulation. Ultimately further research and discovery regarding HIF-1 regulation by oxidative stress is warranted for better understanding of disease development and potential therapeutics for pathologies such as cancer, inflammatory diseases, and ischemia-reperfusion injury. PMID:25546605

  3. 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...

  4. 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

  5. PGC-1α and reactive oxygen species regulate human embryonic stem cell-derived cardiomyocyte function.

    PubMed

    Birket, Matthew J; Casini, Simona; Kosmidis, Georgios; Elliott, David A; Gerencser, Akos A; Baartscheer, Antonius; Schumacher, Cees; Mastroberardino, Pier G; Elefanty, Andrew G; Stanley, Ed G; Mummery, Christine L

    2013-01-01

    Diminished mitochondrial function is causally related to some heart diseases. Here, we developed a human disease model based on cardiomyocytes from human embryonic stem cells (hESCs), in which an important pathway of mitochondrial gene expression was inactivated. Repression of PGC-1α, which is normally induced during development of cardiomyocytes, decreased mitochondrial content and activity and decreased the capacity for coping with energetic stress. Yet, concurrently, reactive oxygen species (ROS) levels were lowered, and the amplitude of the action potential and the maximum amplitude of the calcium transient were in fact increased. Importantly, in control cardiomyocytes, lowering ROS levels emulated this beneficial effect of PGC-1α knockdown and similarly increased the calcium transient amplitude. Our results suggest that controlling ROS levels may be of key physiological importance for recapitulating mature cardiomyocyte phenotypes, and the combination of bioassays used in this study may have broad application in the analysis of cardiac physiology pertaining to disease. PMID:24371810

  6. PGC-1α and Reactive Oxygen Species Regulate Human Embryonic Stem Cell-Derived Cardiomyocyte Function

    PubMed Central

    Birket, Matthew J.; Casini, Simona; Kosmidis, Georgios; Elliott, David A.; Gerencser, Akos A.; Baartscheer, Antonius; Schumacher, Cees; Mastroberardino, Pier G.; Elefanty, Andrew G.; Stanley, Ed G.; Mummery, Christine L.

    2013-01-01

    Summary Diminished mitochondrial function is causally related to some heart diseases. Here, we developed a human disease model based on cardiomyocytes from human embryonic stem cells (hESCs), in which an important pathway of mitochondrial gene expression was inactivated. Repression of PGC-1α, which is normally induced during development of cardiomyocytes, decreased mitochondrial content and activity and decreased the capacity for coping with energetic stress. Yet, concurrently, reactive oxygen species (ROS) levels were lowered, and the amplitude of the action potential and the maximum amplitude of the calcium transient were in fact increased. Importantly, in control cardiomyocytes, lowering ROS levels emulated this beneficial effect of PGC-1α knockdown and similarly increased the calcium transient amplitude. Our results suggest that controlling ROS levels may be of key physiological importance for recapitulating mature cardiomyocyte phenotypes, and the combination of bioassays used in this study may have broad application in the analysis of cardiac physiology pertaining to disease. PMID:24371810

  7. Role of Heme Pocket Water in Allosteric Regulation of Ligand Reactivity in Human Hemoglobin.

    PubMed

    Esquerra, Raymond M; Bibi, Bushra M; Tipgunlakant, Pooncharas; Birukou, Ivan; Soman, Jayashree; Olson, John S; Kliger, David S; Goldbeck, Robert A

    2016-07-26

    Water molecules can enter the heme pockets of unliganded myoglobins and hemoglobins, hydrogen bond with the distal histidine, and introduce steric barriers to ligand binding. The spectrokinetics of photodissociated CO complexes of human hemoglobin and its isolated α and β chains were analyzed for the effect of heme hydration on ligand rebinding. A strong coupling was observed between heme hydration and quaternary state. This coupling may contribute significantly to the 20-60-fold difference between the R- and T-state bimolecular CO binding rate constants and thus to the modulation of ligand reactivity that is the hallmark of hemoglobin allostery. Heme hydration proceeded over the course of several kinetic phases in the tetramer, including the R to T quaternary transition. An initial 150 ns hydration phase increased the R-state distal pocket water occupancy, nw(R), to a level similar to that of the isolated α (∼60%) and β (∼10%) chains, resulting in a modest barrier to ligand binding. A subsequent phase, concurrent with the first step of the R → T transition, further increased the level of heme hydration, increasing the barrier. The final phase, concurrent with the final step of the allosteric transition, brought the water occupancy of the T-state tetramer, nw(T), even higher and close to full occupancy in both the α and β subunits (∼90%). This hydration level could present an even larger barrier to ligand binding and contribute significantly to the lower iron reactivity of the T state toward CO. PMID:27355904

  8. 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.

  9. Stress Regulation in Adolescents: Physiological Reactivity during the Adult Attachment Interview and Conflict Interaction

    ERIC Educational Resources Information Center

    Beijersbergen, Marielle D.; Bakermans-Kranenburg, Marian J.; van IJzendoorn, Marinus H.; Juffer, Femmie

    2008-01-01

    The current study examined whether adolescents' attachment representations were associated with differences in emotion regulation during the Adult Attachment Interview (AAI; C. George, N. Kaplan, & M. Main, 1996) and during a mother-adolescent conflict interaction task (Family Interaction Task [FIT]; J. P. Allen et al., 2003). Participants were…

  10. 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.…

  11. Zhx2 and Zbtb20: Novel regulators of postnatal alpha-fetoprotein repression and their potential role in gene reactivation during liver cancer

    PubMed Central

    Peterson, Martha L.; Ma, Chunhong; Spear, Brett T.

    2012-01-01

    The mouse alpha-fetoprotein (AFP) gene is abundantly expressed in the fetal liver, normally silent in the adult liver but is frequently reactivated in hepatocellular carcinoma. The basis for AFP expression in the fetal liver has been studied extensively. However, the basis for AFP reactivation during hepatocarcinogenesis is not well understood. Two novel factors that control postnatal AFP repression, Zhx2 and Zbtb20, were recently identified. Here, we review the transcription factors that regulate AFP in the fetal liver, as well as Zhx2 and Zbtb20, and raise the possibility that the loss of these postnatal repressors may be involved in AFP reactivation in liver cancer. PMID:21216289

  12. Role of reactive oxygen species in the regulation of HIF-1 by prolyl hydroxylase 2 under mild hypoxia.

    PubMed

    Niecknig, Helene; Tug, Suzan; Reyes, Buena Delos; Kirsch, Michael; Fandrey, Joachim; Berchner-Pfannschmidt, Utta

    2012-06-01

    The function and survival of eukaryotic cells depends on a constant and sufficient oxygen supply. Cells recognize and respond to hypoxia by accumulation of the transcription factor hypoxia-inducible factor 1 (HIF-1), composed of an oxygen-sensitive HIF-1α and a constitutive HIF-1β subunit. Besides physiology, HIF-1 induction is involved in major pathological processes such as cardiovascular disease, inflammation and cancer, which are associated with the formation of reactive oxygen species (ROS). ROS have been reported to affect HIF-1 activity but the role for ROS in regulating HIF-1 has not been definitely settled. In order to shed light on the redox-regulation of HIF-1 by ROS, we studied the impact of exogenous ROS treatment (H(2)O(2)) on HIF-1α and HIF-1 regulatory protein prolyl hydroxylase 2 (PHD2) in the human osteosarcoma cell line U2OS. At early reaction periods, H(2)O(2) induced HIF-1α but at prolonged observation phases the opposite occurred. Herein, modulation of PHD activity appeared to be the key element, because knockdown and inhibition of the PHD2 prevented reduction of HIF-1α. However, H(2)O(2) treatment constantly suppressed HIF-1 transactivation at all time-points. Our data indicate a dual redox regulation of HIF-1α protein amount with a constant suppression of HIF-1 target gene expression by ROS. PMID:22360728

  13. 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

    2015-07-01

    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. PMID:25957768

  14. 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

  15. Reactive Oxygen Species Affect Transglutaminase Activity and Regulate Hematopoiesis in a Crustacean.

    PubMed

    Junkunlo, Kingkamon; Söderhäll, Kenneth; Söderhäll, Irene; Noonin, Chadanat

    2016-08-19

    Reactive oxygen species (ROS) serve as a prime signal in the commitment to hematopoiesis in both mammals and Drosophila In this study, the potential function of ROS during hematopoiesis in the crayfish Pacifastacus leniusculus was examined. The antioxidant N-acetylcysteine (NAC) was used to decrease ROS in both in vivo and in vitro experiments. An increase in ROS was observed in the anterior proliferation center (APC) after LPS injection. In the absence of NAC, the LPS-induced increase in ROS levels resulted in the rapid restoration of the circulating hemocyte number. In the presence of NAC, a delay in the recovery rate of the hemocyte number was observed. NAC treatment also blocked the spread of APC and other hematopoietic tissue (HPT) cells, maintaining these cells at an undifferentiated stage. Extracellular transglutaminase (TGase) has been shown previously to play a role in maintaining HPT cells in an undifferentiated form. In this study, we show that extracellular TGase activity increased when the ROS level in HPT or APC cells was reduced after NAC treatment. In addition, collagen, a major component of the extracellular matrix and a TGase substrate were co-localized on the HPT cell surface. Taken together, the results of this study show that ROS are involved in crayfish hematopoiesis, in which a low ROS level is required to maintain hematopoietic progenitor cells in the tissue and to reduce hemocyte release. The potential roles of TGase in this process are investigated and discussed. PMID:27339892

  16. Reactive oxygen species are involved in insulin-dependent regulation of autophagy in primary rat podocytes.

    PubMed

    Audzeyenka, Irena; Rogacka, Dorota; Piwkowska, Agnieszka; Rychlowski, Michal; Bierla, Joanna Beata; Czarnowska, Elżbieta; Angielski, Stefan; Jankowski, Maciej

    2016-06-01

    Autophagy is an intracellular defense mechanism responsible for the turnover of damaged or non-functional cellular constituents. This process provides cells with energy and essential compounds under unfavorable environmental conditions-such as oxidative stress and hyperglycemia, which are both observed in diabetes. The most common diabetes complication is diabetic nephropathy (DN), which can lead to renal failure. This condition often includes impaired podocyte function. Here we investigated autophagic activity in rat podocytes cultured with a high insulin concentration (300nM). Autophagy was activated after 60min of insulin stimulation. Moreover, this effect was abolished following pharmacological (apocynin) or genetic (siRNA) inhibition of NAD(P)H oxidase activity, indicating that insulin-dependent autophagy stimulation involved reactive oxygen species (ROS). We also observed a continuous and time-dependent increase of podocyte albumin permeability in response to insulin, and this process was slightly improved by autophagy inhibition following short-term insulin exposure. Our results suggest that insulin may be a factor affecting the development of diabetic nephropathy. PMID:27026581

  17. 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

  18. 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

  19. 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. PMID:26791627

  20. Regulation loops for the ring magnet power supplies in the SSC accelerator complex

    SciTech Connect

    Tacconi, E.; Christiansen, C.

    1993-05-01

    The SSC complex consists of five cascaded accelerators: The linear accelerator (linac) and four synchrotrons: The low energy booster (LEB), the medium energy booster (MEB), the high energy booster (HEB), and the collider. Twelve- or 24-pulse phase-controlled SCR power supplies are used to energize the ring magnets. Each power supply has a voltage loop designed to regulate the voltage applied to the magnets. The voltage regulation loops for these synchrotrons and the current regulation for the LEB are analyzed in this work. The digital voltage regulator is fiber-optic isolated from the power converter. It has a closed-loop bandwidth of 150 Hz with band rejections for 60-Hz and 120-Hz perturbations. The LEB has a very precise current regulation system composed of a feedforward compensator, a fast feedback regulator, and a slow synchronous regulator. The current regulation design is corroborated by computer simulations.

  1. Influence of inert gases on the reactive high power pulsed magnetron sputtering process of carbon-nitride thin films

    SciTech Connect

    Schmidt, Susann; Czigany, Zsolt; Greczynski, Grzegorz; Jensen, Jens; Hultman, Lars

    2013-01-15

    The influence of inert gases (Ne, Ar, Kr) on the sputter process of carbon and carbon-nitride (CN{sub x}) thin films was studied using reactive high power pulsed magnetron sputtering (HiPIMS). Thin solid films were synthesized in an industrial deposition chamber from a graphite target. The peak target current during HiPIMS processing was found to decrease with increasing inert gas mass. Time averaged and time resolved ion mass spectroscopy showed that the addition of nitrogen, as reactive gas, resulted in less energetic ion species for processes employing Ne, whereas the opposite was noticed when Ar or Kr were employed as inert gas. Processes in nonreactive ambient showed generally lower total ion fluxes for the three different inert gases. As soon as N{sub 2} was introduced into the process, the deposition rates for Ne and Ar-containing processes increased significantly. The reactive Kr-process, in contrast, showed slightly lower deposition rates than the nonreactive. The resulting thin films were characterized regarding their bonding and microstructure by x-ray photoelectron spectroscopy and transmission electron microscopy. Reactively deposited CN{sub x} thin films in Ar and Kr ambient exhibited an ordering toward a fullerene-like structure, whereas carbon and CN{sub x} films deposited in Ne atmosphere were found to be amorphous. This is attributed to an elevated amount of highly energetic particles observed during ion mass spectrometry and indicated by high peak target currents in Ne-containing processes. These results are discussed with respect to the current understanding of the structural evolution of a-C and CN{sub x} thin films.

  2. 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. PMID:27340757

  3. 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.

  4. Reactive Nitrogen Species and Hydrogen Sulfide as Regulators of Protein Tyrosine Phosphatase Activity

    PubMed Central

    2014-01-01

    Abstract Significance: Redox modifications of thiols serve as a molecular code enabling precise and complex regulation of protein tyrosine phosphatases (PTPs) and other proteins. Particular gasotransmitters and even the redox modifications themselves affect each other, of which a typical example is S-nitrosylation-mediated protection against the further oxidation of protein thiols. Recent Advances: For a long time, PTPs were considered constitutively active housekeeping enzymes. This view has changed substantially over the last two decades, and the PTP family is now recognized as a group of tightly and flexibly regulated fundamental enzymes. In addition to the conventional ways in which they are regulated, including noncovalent interactions, phosphorylation, and oxidation, the evidence that has accumulated during the past two decades suggests that many of these enzymes are also modulated by gasotransmitters, namely by nitric oxide (NO) and hydrogen sulfide (H2S). Critical Issues: The specificity and selectivity of the methods used to detect nitrosylation and sulfhydration remains to be corroborated, because several researchers raised the issue of false-positive results, particularly when using the most widespread biotin switch method. Further development of robust and straightforward proteomic methods is needed to further improve our knowledge of the full extent of the gasotransmitters-mediated changes in PTP activity, selectivity, and specificity. Further Directions: Results of the hitherto performed studies on gasotransmitter-mediated PTP signaling await translation into clinical medicine and pharmacotherapeutics. In addition to directly affecting the activity of particular PTPs, the use of reversible S-nitrosylation as a protective mechanism against oxidative stress should be of high interest. Antioxid. Redox Signal. 20, 2191–2209. PMID:24328688

  5. 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.

  6. 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. PMID:24417418

  7. Early Experience and the Development of Stress Reactivity and Regulation in Children

    PubMed Central

    Loman, Michelle M.; Gunnar, Megan R.

    2009-01-01

    Children who spend early portions of their lives in institutions or those maltreated in their families of origin are at risk for developing emotional and behavioral problems reflecting disorders of emotion and attention regulation. Animal models may help explicate the mechanisms producing these effects. Despite the value of the animal models, many questions remain in using the animal data to guide studies of human development. In 1999, the National Institute of Mental Health in the United States funded a research network to address unresolved issues and enhance translation of basic animal early experience research to application in child research. Professor Seymour Levine was both the inspiration for and an active member of this research network until his death in October of 2007. This review pays tribute to his legacy by outlining the conceptual model which is now guiding our research studies. PMID:19481109

  8. Reactive oxygen species effect PASMCs apoptosis via regulation of dynamin-related protein 1 in hypoxic pulmonary hypertension.

    PubMed

    Zhang, Lixin; Ma, Cui; Zhang, Chen; Ma, Mingfei; Zhang, Fengying; Zhang, Linlin; Chen, Yingli; Cao, Fangyuan; Li, Shuzhen; Zhu, Daling

    2016-07-01

    The high level of reactive oxygen species and up-regulation of mitochondrial fission protein dynamin-related protein-1, both of which involved in pulmonary artery smooth muscle cells (PASMCs) apoptosis, have been detected in the lungs of rodent pulmonary arterial hypertension models. However, the regulatory mechanisms between ROS and DRP1 are poorly understood. In this study, ROS inhibitor, hypoxic rodent PAH models, small interfering RNA, polymerase chain reaction, Western blot, flow cytometry, immunohistochemistry and immunofluorescence were used. We determined that ROS, mainly derive from mitochondria, mediate mitochondria fission of PASMCs contributing to pulmonary vascular remodeling. Meanwhile, we also observed that hypoxia-induced DRP1 expression depends on ROS generation, especially mitochondrial ROS (mROS). Moreover, the levels of ROS and mROS evoked by hypoxia were regulated by DRP1. Furthermore, we verified the apoptosis suppression of PASMCs under hypoxia due to the interaction between ROS/mROS and DRP1. Our study reveals a novel mechanism of hypoxia-induced pulmonary vascular remodeling, suggesting a new therapeutic strategy which is targeting on the positive feedback of ROS/mROS-DRP1 for the treatment of PAH. PMID:27010815

  9. K 4R - Knowledge to the Power of RESTful, Resourceful and Reactive Rules

    NASA Astrophysics Data System (ADS)

    Amador, Ricardo

    The Web of today clearly answers questions of the form "What is the representation of ...?". The Semantic Web (SW) of tomorrow aims at answering questions of the form "What is the meaning of ...?". It is our stance that in order to realize the full potential of the original concept proposed by Tim Berners-Lee et al. (in Scientific American, May 2001), the SW must also answer, in a meaningful way, questions of a dynamic and active nature, like "What to do if ...?" or "What to do when ...?". Moreover, SW questions of the form "What to do ...?" must be expressed and answered in a declarative, compositional and language agnostic way. It is our (hypo)thesis that formally established concepts, viz. the Web's REST architectural style, declarative SW representation of resources based on Description Logics (e.g., OWL-DL), and Reactive Rules (e.g., "on Event if Condition do Action" -ECA- rules), provide the proper theoretical foundations to achieve this goal. This paper describes our current research proposal, K 4R (pronounced, with an Italian flavor, "Che fare?"), towards achieving a declarative model for expressing (re)active behavior in and for the SW.

  10. Computation and Experiment: A Powerful Combination to Understand and Predict Reactivities.

    PubMed

    Sperger, Theresa; Sanhueza, Italo A; Schoenebeck, Franziska

    2016-06-21

    Computational chemistry has become an established tool for the study of the origins of chemical phenomena and examination of molecular properties. Because of major advances in theory, hardware and software, calculations of molecular processes can nowadays be done with reasonable accuracy on a time-scale that is competitive or even faster than experiments. This overview will highlight broad applications of computational chemistry in the study of organic and organometallic reactivities, including catalytic (NHC-, Cu-, Pd-, Ni-catalyzed) and noncatalytic examples of relevance to organic synthesis. The selected examples showcase the ability of computational chemistry to rationalize and also predict reactivities of broad significance. A particular emphasis is placed on the synergistic interplay of computations and experiments. It is discussed how this approach allows one to (i) gain greater insight than the isolated techniques, (ii) inspire novel chemistry avenues, and (iii) assist in reaction development. Examples of successful rationalizations of reactivities are discussed, including the elucidation of mechanistic features (radical versus polar) and origins of stereoselectivity in NHC-catalyzed reactions as well as the rationalization of ligand effects on ligation states and selectivity in Pd- and Ni-catalyzed transformations. Beyond explaining, the synergistic interplay of computation and experiments is then discussed, showcasing the identification of the likely catalytically active species as a function of ligand, additive, and solvent in Pd-catalyzed cross-coupling reactions. These may vary between mono- or bisphosphine-bound or even anionic Pd complexes in polar media in the presence of coordinating additives. These fundamental studies also inspired avenues in catalysis via dinuclear Pd(I) cycles. Detailed mechanistic studies supporting the direct reactivity of Pd(I)-Pd(I) with aryl halides as well as applications of air-stable dinuclear Pd(I) catalysts are

  11. Three-dimensional Reluctance Network Analysis of an EIE-Core Variable Inductor and Application to Reactive Power Compensation in a Distribution System

    NASA Astrophysics Data System (ADS)

    Nakamura, Kenji; Ohinata, Takashi; Arimatsu, Kenji; Sakamoto, Kunio; Ichinokura, Osamu

    This paper describes a three-dimensional reluctance network analysis (RNA) of an EIE-core variable inductor, which can be applied as a reactive power compensator in electric power systems. First, a three-dimensional RNA model of an EIE-core considering the magnetic saturation and iron loss is presented. Using the proposed RNA model with external electric circuits, operating characteristics of the variable inductor including the iron loss are calculated accurately. Next, high performance of a 6.6 kV-300 kVA reactive power compensator using the EIE-core variable inductor is demonstrated in a distribution system.

  12. Analysis and Performance of a 12-Pulse High Power Regulator

    NASA Technical Reports Server (NTRS)

    Silva, Arnold; Daeges, John

    1994-01-01

    Under work being performed to upgrade the 20 Kilowatt CW uplink transmitters of the NASA Deep Space Network (DSN), the high voltage regulator has been revisited in order to optimize its performance (long-term stability and regulation), and enhance field reliability.

  13. 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

  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. SiNx Coatings Deposited by Reactive High Power Impulse Magnetron Sputtering: Process Parameters Influencing the Nitrogen Content.

    PubMed

    Schmidt, Susann; Hänninen, Tuomas; Goyenola, Cecilia; Wissting, Jonas; Jensen, Jens; Hultman, Lars; Goebbels, Nico; Tobler, Markus; Högberg, Hans

    2016-08-10

    Reactive high power impulse magnetron sputtering (rHiPIMS) was used to deposit silicon nitride (SiNx) coatings for biomedical applications. The SiNx growth and plasma characterization were conducted in an industrial coater, using Si targets and N2 as reactive gas. The effects of different N2-to-Ar flow ratios between 0 and 0.3, pulse frequencies, target power settings, and substrate temperatures on the discharge and the N content of SiNx coatings were investigated. Plasma ion mass spectrometry shows high amounts of ionized isotopes during the initial part of the pulse for discharges with low N2-to-Ar flow ratios of <0.16, while signals from ionized molecules rise with the N2-to-Ar flow ratio at the pulse end and during pulse-off times. Langmuir probe measurements show electron temperatures of 2-3 eV for nonreactive discharges and 5.0-6.6 eV for discharges in transition mode. The SiNx coatings were characterized with respect to their composition, chemical bond structure, density, and mechanical properties by X-ray photoelectron spectroscopy, X-ray reflectivity, X-ray diffraction, and nanoindentation, respectively. The SiNx deposition processes and coating properties are mainly influenced by the N2-to-Ar flow ratio and thus by the N content in the SiNx films and to a lower extent by the HiPIMS frequencies and power settings as well as substrate temperatures. Increasing N2-to-Ar flow ratios lead to decreasing growth rates, while the N content, coating densities, residual stresses, and the hardness increase. These experimental findings were corroborated by density functional theory calculations of precursor species present during rHiPIMS. PMID:27414283

  16. 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

  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. Cystic Fibrosis Transmembrane Conductance Regulator: Using Differential Reactivity toward Channel-Permeant and Channel-Impermeant Thiol-Reactive Probes To Test a Molecular Model for the Pore†

    PubMed Central

    2009-01-01

    The sixth transmembrane segment (TM6) of the CFTR chloride channel has been intensively investigated. The effects of amino acid substitutions and chemical modification of engineered cysteines (cysteine scanning) on channel properties strongly suggest that TM6 is a key component of the anion-conducting pore, but previous cysteine-scanning studies of TM6 have produced conflicting results. Our aim was to resolve these conflicts by combining a screening strategy based on multiple, thiol-directed probes with molecular modeling of the pore. CFTR constructs were screened for reactivity toward both channel-permeant and channel-impermeant thiol-directed reagents, and patterns of reactivity in TM6 were mapped onto two new, molecular models of the CFTR pore: one based on homology modeling using Sav1866 as the template and a second derived from the first by molecular dynamics simulation. Comparison of the pattern of cysteine reactivity with model predictions suggests that nonreactive sites are those where the TM6 side chains are occluded by other TMs. Reactive sites, in contrast, are generally situated such that the respective amino acid side chains either project into the predicted pore or lie within a predicted extracellular loop. Sites where engineered cysteines react with both channel-permeant and channel-impermeant probes occupy the outermost extent of TM6 or the predicted TM5−6 loop. Sites where cysteine reactivity is limited to channel-permeant probes occupy more cytoplasmic locations. The results provide an initial validation of two, new molecular models for CFTR and suggest that molecular dynamics simulation will be a useful tool for unraveling the structural basis of anion conduction by CFTR. PMID:19754156

  19. Power regulation of kinematic control inputs for forward flying Drosophila

    NASA Astrophysics Data System (ADS)

    MacFarlane, Kenneth; Faruque, Imraan; Sean Humbert, J.

    2014-12-01

    The choices of insect wing kinematic programs is not well understood, particularly the mechanism by which an insect selects a distortion to achieve flight control. A methodology to evaluate prospective kinematic control inputs is presented based on the reachable states when control actuation was constrained to a unit of power. The method implements a computationally-derived reduced order model of the insect's flight dynamics combined with calculation of power requirement. Four kinematic inputs are evaluated based on this criterion for a Drosophila size insect in forward flight. Stroke bias is shown to be the dominant control input using this power normalized evaluation measure.

  20. The Failure Analysis of Paralleled Solar Array Regulator for Satellite Power System in Low Earth Orbit

    NASA Astrophysics Data System (ADS)

    Jang, Sung-Soo; Kim, Sung-Hoon; Lee, Sang-Ryool; Choi, Jaeho

    2011-06-01

    A satellite power system should generate and supply sufficient electric power to perform the satellite mission successfully during the satellite mission period, and it should be developed to be strong to the failure caused by the severe space environment. A satellite power system must have a high reliability with respect to failure. Since it cannot be repaired after launching, different from a ground system, the failures that may happen in space as well as the effect of the failures on the system should be considered in advance. However, it is difficult to use all the hardware to test the performance of the satellite power system to be developed in order to consider the failure mechanism of the electrical power system. Therefore, it is necessary to develop an accurate model for the main components of a power system and, based on that, to develop an accurate model for the entire power system. Through the power system modeling, the overall effect of failure on the main components of the power system can be considered and the protective design can be devised against the failure. In this study, to analyze the failure mode of the power system and the effects of the failure on the power system, we carried out modeling of the main power system components including the solar array regulator, and constituted the entire power system based on the modeling. Additionally, we investigated the effects of representative failures in the solar array regulator on the power system using the power system model.

  1. 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.

  2. Subwavelength structures for high power laser antireflection application on fused silica by one-step reactive ion etching

    NASA Astrophysics Data System (ADS)

    Ye, Xin; Jiang, Xiao-Dong; Huang, Jin; Sun, Lai-Xi; Geng, Feng; Yi, Zao; Zu, Xiao-Tao; Wu, Wei-Dong; Zheng, Wanguo

    2016-03-01

    In this paper we report a simple method to fabricate a novel subwavelength structure surface on fused silica substrate using one-step reactive ion etching with two-dimensional polystyrene colloidal crystals as masks. The etching process and the morphologies of the obtained structure are controlled. We show that the period of the obtained fused silica pillar-like arrays were determined by the initial polystyrene nanoparticle size. The height of pillar arrays can be adjusted by controlling the etching duration, which is proved to be of importance in tailoring the antireflection properties of subwavelength structures surface. The novel subwavelength structures surface exhibit excellent broadband antireflection properties, but the size of the pillar affects the antireflective properties in short wavelength region. We anticipate this method would offer a convenient and scalable way for inexpensive and high-efficiency high power laser field designs.

  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. Trolox-Sensitive Reactive Oxygen Species Regulate Mitochondrial Morphology, Oxidative Phosphorylation and Cytosolic Calcium Handling in Healthy Cells

    PubMed Central

    Distelmaier, Felix; Valsecchi, Federica; Forkink, Marleen; van Emst-de Vries, Sjenet; Swarts, Herman G.; Rodenburg, Richard J.T.; Verwiel, Eugène T.P.; Smeitink, Jan A.M.; Willems, Peter H.G.M.

    2012-01-01

    Abstract Aims: Cell regulation by signaling reactive oxygen species (sROS) is often incorrectly studied through extracellular oxidant addition. Here, we used the membrane-permeable antioxidant Trolox to examine the role of sROS in mitochondrial morphology, oxidative phosphorylation (OXPHOS), and cytosolic calcium (Ca2+) handling in healthy human skin fibroblasts. Results and Innovation: Trolox treatment reduced the levels of 5-(and-6)-chloromethyl-2′,7′-dichlorodihydro-fluorescein (CM-H2DCF) oxidizing ROS, lowered cellular lipid peroxidation, and induced a less oxidized mitochondrial thiol redox state. This was paralleled by increased glutathione- and mitofusin-dependent mitochondrial filamentation, increased expression of fully assembled mitochondrial complex I, elevated activity of citrate synthase and OXPHOS enzymes, and a higher cellular O2 consumption. In contrast, Trolox did not alter hydroethidium oxidation, cytosolic thiol redox state, mitochondrial NAD(P)H levels, or mitochondrial membrane potential. Whole genome expression profiling revealed that Trolox did not trigger significant changes in gene expression, suggesting that Trolox acts downstream of this process. Cytosolic Ca2+ transients, induced by the hormone bradykinin, were of a higher amplitude and decayed faster in Trolox-treated cells. These effects were dose-dependently antagonized by hydrogen peroxide. Conclusions: Our findings suggest that Trolox-sensitive sROS are upstream regulators of mitochondrial mitofusin levels, morphology, and function in healthy human skin fibroblasts. This information not only facilitates the interpretation of antioxidant effects in cell models (of oxidative-stress), but also contributes to a better understanding of ROS-related human pathologies, including mitochondrial disorders. Antioxid. Redox Signal. 17, 1657–1669. PMID:22559215

  5. 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.

  6. Vascular Cell Adhesion Molecule-1 Expression and Signaling During Disease: Regulation by Reactive Oxygen Species and Antioxidants

    PubMed Central

    Marchese, Michelle E.; Abdala-Valencia, Hiam

    2011-01-01

    Abstract The endothelium is immunoregulatory in that inhibiting the function of vascular adhesion molecules blocks leukocyte recruitment and thus tissue inflammation. The function of endothelial cells during leukocyte recruitment is regulated by reactive oxygen species (ROS) and antioxidants. In inflammatory sites and lymph nodes, the endothelium is stimulated to express adhesion molecules that mediate leukocyte binding. Upon leukocyte binding, these adhesion molecules activate endothelial cell signal transduction that then alters endothelial cell shape for the opening of passageways through which leukocytes can migrate. If the stimulation of this opening is blocked, inflammation is blocked. In this review, we focus on the endothelial cell adhesion molecule, vascular cell adhesion molecule-1 (VCAM-1). Expression of VCAM-1 is induced on endothelial cells during inflammatory diseases by several mediators, including ROS. Then, VCAM-1 on the endothelium functions as both a scaffold for leukocyte migration and a trigger of endothelial signaling through NADPH oxidase-generated ROS. These ROS induce signals for the opening of intercellular passageways through which leukocytes migrate. In several inflammatory diseases, inflammation is blocked by inhibition of leukocyte binding to VCAM-1 or by inhibition of VCAM-1 signal transduction. VCAM-1 signal transduction and VCAM-1-dependent inflammation are blocked by antioxidants. Thus, VCAM-1 signaling is a target for intervention by pharmacological agents and by antioxidants during inflammatory diseases. This review discusses ROS and antioxidant functions during activation of VCAM-1 expression and VCAM-1 signaling in inflammatory diseases. Antioxid. Redox Signal. 15, 1607–1638. PMID:21050132

  7. Mitochondrial Reactive Oxygen Species Regulate Adipocyte Differentiation of Mesenchymal Stem Cells in Hematopoietic Stress Induced by Arabinosylcytosine

    PubMed Central

    Wang, Weimin; Zhang, Yao; Lu, Wenyi; Liu, Kaiyan

    2015-01-01

    Objective The increase in adipocytes induced by chemotherapeutic drugs may play a negative role in hematopoietic recovery. However, the mechanism underlying adipocyte differentiation of mesenchymal stem cells (MSCs) in hematopoietic stress is still unknown. Hence, the involvement of reactive oxygen species (ROS) in adipocyte differentiation under hematopoietic stress was investigated in vitro and in vivo. Methods The roles of cellular ROS in adipogenesis were investigated in vivo through an adipocyte hyperplasia marrow model under hematopoietic stress induced by arabinosylcytosine (Ara-C) and in vitro via adipocyte differentiation of human MSCs. ROS levels were detected using the CM-H2DCFDA probe and Mito-SOX dye. Adipogenesis was evaluated by histopathology and oil red O staining, whereas detection of mRNA levels of antioxidant enzymes and adipogenesis markers was performed using quantitative real-time polymerase chain reaction analysis. Results ROS were found to play an important role in regulating adipocyte differentiation of MSCs by activating peroxisome proliferator-activated receptor gamma (PPARγ,) while the antioxidant N-acetyl-L-cysteine acts through ROS to inhibit adipocyte differentiation. The elevated ROS levels induced by Ara-C were caused by both over-generation of mitochondrial ROS and reduction of antioxidant enzymes (Cu/Zn Superoxide dismutase and catalase). Our findings suggest that a mitochondrial-targeted antioxidant could diminish adipocyte differentiation. PMID:25768922

  8. 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

  9. Neurofibromin is a novel regulator of Ras-induced reactive oxygen species production in mice and humans.

    PubMed

    Bessler, Waylan K; Hudson, Farlyn Z; Zhang, Hanfang; Harris, Valerie; Wang, Yusi; Mund, Julie A; Downing, Brandon; Ingram, David A; Case, Jamie; Fulton, David J; Stansfield, Brian K

    2016-08-01

    Neurofibromatosis type 1 (NF1) predisposes individuals to early and debilitating cardiovascular disease. Loss of function mutations in the NF1 tumor suppressor gene, which encodes the protein neurofibromin, leads to accelerated p21(Ras) activity and phosphorylation of multiple downstream kinases, including Erk and Akt. Nf1 heterozygous (Nf1(+/-)) mice develop a robust neointima that mimics human disease. Monocytes/macrophages play a central role in NF1 arterial stenosis as Nf1 mutations in myeloid cells alone are sufficient to reproduce the enhanced neointima observed in Nf1(+/-) mice. Though the molecular mechanisms underlying NF1 arterial stenosis remain elusive, macrophages are important producers of reactive oxygen species (ROS) and Ras activity directly regulates ROS production. Here, we use compound mutant and lineage-restricted mice to demonstrate that Nf1(+/-) macrophages produce excessive ROS, which enhance Nf1(+/-) smooth muscle cell proliferation in vitro and in vivo. Further, use of a specific NADPH oxidase-2 inhibitor to limit ROS production prevents neointima formation in Nf1(+/-) mice. Finally, mononuclear cells from asymptomatic NF1 patients have increased oxidative DNA damage, an indicator of chronic exposure to oxidative stress. These data provide genetic and pharmacologic evidence that excessive exposure to oxidant species underlie NF1 arterial stenosis and provide a platform for designing novels therapies and interventions. PMID:27266634

  10. Allicin attenuates H₂O₂-induced cytotoxicity in retinal pigmented epithelial cells by regulating the levels of reactive oxygen species.

    PubMed

    Tu, Gerile; Zhang, Yu-Feng; Wei, Wei; Li, Langen; Zhang, Yanmei; Yang, Jia; Xing, Yiqiao

    2016-03-01

    Retinal pigmented epithelial cell (RPE) oxidative stress is known to have a vital role in the etiology of age‑related macular degeneration (AMD). The present study aimed to investigate whether allicin, a natural product with antioxidant activity, was able to protect RPEs (ARPE‑19) from hydrogen peroxide (H2O2)‑induced damage, and to determine the underlying mechanisms. The 3-(4,5-dimethylthiazol-2-yl)-2,5‑diphenyl tetrazolium bromide assay was used to determine cellular viability, and reactive oxygen species (ROS) were detected using a ROS Assay kit. The results demonstrated that allicin was able to protect ARPE‑19 cells from H2O2‑induced damage in a dose‑dependent manner. In addition, allicin attenuated oxidative stress by reducing the levels of intracellular ROS and malondialdehyde (MDA), and enhancing the glutathione/glutathione disulfide (GSSG) ratio. With regards to the underlying mechanism, allicin was able to markedly modulate the expression levels of ROS‑associated enzymes, including superoxide dismutase, NADPH oxidase 4 and NAD(P)H dehydrogenase quinone 1, and elevate the activity of nuclear factor erythroid 2‑related factor 2 in the H2O2‑stimulated ARPE‑19 cells. These results suggested that allicin may exert protective effects against H2O2‑induced cytotoxicity in RPEs via ROS regulation. PMID:26781848

  11. 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

  12. Ca(II) Binding Regulates and Dominates the Reactivity of a Transition-Metal-Ion-Dependent Diesterase from Mycobacterium tuberculosis.

    PubMed

    Pedroso, Marcelo M; Larrabee, James A; Ely, Fernanda; Gwee, Shuhui E; Mitić, Nataša; Ollis, David L; Gahan, Lawrence R; Schenk, Gerhard

    2016-01-18

    The diesterase Rv0805 from Mycobacterium tuberculosis is a dinuclear metallohydrolase that plays an important role in signal transduction by controlling the intracellular levels of cyclic nucleotides. As Rv0805 is essential for mycobacterial growth it is a promising new target for the development of chemotherapeutics to treat tuberculosis. The in vivo metal-ion composition of Rv0805 is subject to debate. Here, we demonstrate that the active site accommodates two divalent transition metal ions with binding affinities ranging from approximately 50 nm for Mn(II) to about 600 nm for Zn(II) . In contrast, the enzyme GpdQ from Enterobacter aerogenes, despite having a coordination sphere identical to that of Rv0805, binds only one metal ion in the absence of substrate, thus demonstrating the significance of the outer sphere to modulate metal-ion binding and enzymatic reactivity. Ca(II) also binds tightly to Rv0805 (Kd ≈40 nm), but kinetic, calorimetric, and spectroscopic data indicate that two Ca(II) ions bind at a site different from the dinuclear transition-metal-ion binding site. Ca(II) acts as an activator of the enzymatic activity but is able to promote the hydrolysis of substrates even in the absence of transition-metal ions, thus providing an effective strategy for the regulation of the enzymatic activity. PMID:26662456

  13. 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. PMID:27208820

  14. 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.

  15. Reactive Inkjet Printing of Biocompatible Enzyme Powered Silk Micro-Rockets.

    PubMed

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

    2016-08-01

    Inkjet-printed enzyme-powered silk-based micro-rockets are able to undergo autonomous motion in a vast variety of fluidic environments including complex media such as human serum. By means of digital inkjet printing it is possible to alter the catalyst distribution simply and generate varying trajectory behavior of these micro-rockets. Made of silk scaffolds containing enzymes these micro-rockets are highly biocompatible and non-biofouling. PMID:27345008

  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. K-bZIP Mediated SUMO-2/3 Specific Modification on the KSHV Genome Negatively Regulates Lytic Gene Expression and Viral Reactivation.

    PubMed

    Yang, Wan-Shan; Hsu, Hung-Wei; Campbell, Mel; Cheng, Chia-Yang; Chang, Pei-Ching

    2015-07-01

    SUMOylation is associated with epigenetic regulation of chromatin structure and transcription. Epigenetic modifications of herpesviral genomes accompany the transcriptional switch of latent and lytic genes during the virus life cycle. Here, we report a genome-wide comparison of SUMO paralog modification on the KSHV genome. Using chromatin immunoprecipitation in conjunction with high-throughput sequencing, our study revealed highly distinct landscape changes of SUMO paralog genomic modifications associated with KSHV reactivation. A rapid and widespread deposition of SUMO-2/3, compared with SUMO-1, modification across the KSHV genome upon reactivation was observed. Interestingly, SUMO-2/3 enrichment was inversely correlated with H3K9me3 mark after reactivation, indicating that SUMO-2/3 may be responsible for regulating the expression of viral genes located in low heterochromatin regions during viral reactivation. RNA-sequencing analysis showed that the SUMO-2/3 enrichment pattern positively correlated with KSHV gene expression profiles. Activation of KSHV lytic genes located in regions with high SUMO-2/3 enrichment was enhanced by SUMO-2/3 knockdown. These findings suggest that SUMO-2/3 viral chromatin modification contributes to the diminution of viral gene expression during reactivation. Our previous study identified a SUMO-2/3-specific viral E3 ligase, K-bZIP, suggesting a potential role of this enzyme in regulating SUMO-2/3 enrichment and viral gene repression. Consistent with this prediction, higher K-bZIP binding on SUMO-2/3 enrichment region during reactivation was observed. Moreover, a K-bZIP SUMO E3 ligase dead mutant, K-bZIP-L75A, in the viral context, showed no SUMO-2/3 enrichment on viral chromatin and higher expression of viral genes located in SUMO-2/3 enriched regions during reactivation. Importantly, virus production significantly increased in both SUMO-2/3 knockdown and KSHV K-bZIP-L75A mutant cells. These results indicate that SUMO-2/3 modification

  18. 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. PMID:24796661

  19. 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…

  20. 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…

  1. 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

  2. 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.

  3. 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...

  4. 77 FR 35671 - Conformed Power Marketing Criteria or Regulations for the Boulder Canyon Project

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-14

    ..., 1987. On December 28, 1984, Western published the 1984 Conformed Criteria (49 FR 50582) to implement... Federal Register (49 FR 50582) on December 28, 1984. These 2012 Conformed Criteria establish general... Area Power Administration Conformed Power Marketing Criteria or Regulations for the Boulder...

  5. 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

  6. 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

  7. Reactive Oxygen Species Are Involved in Regulating Hypocontractility of Mesenteric Artery to Norepinephrine in Cirrhotic Rats with Portal Hypertension

    PubMed Central

    Chen, Wei; Liu, De-Jun; Huo, Yan-Miao; Wu, Zhi-Yong; Sun, Yong-Wei

    2014-01-01

    Background: Oxidative stress is involved in the hypocontractility of visceral artery to vasoconstrictors and formation of hyperdynamic circulation in cirrhosis with portal hypertension. In the present study, we investigated the effect of reactive oxygen species (ROS) on the mesenteric artery contractility in CCl4-induced cirrhotic rats, and the roles of G protein-coupled receptors (GPCRs) desensitization and RhoA /Rho associated coiled-coil forming protein kinase (ROCK) pathways. Methods: The mesenteric artery contraction to norepinephrine (NE) was determined by vessel perfusion system following treatments with apocynin, tempol or PEG-catalase. The protein expression of α1 adrenergic receptor, β-arrestin-2, ROCK-1, moesin and p-moesin was measured by western blot. The interaction between α1 adrenergic receptor and β-arrestin-2 was assessed by co-immunoprecipitation. Results: Pretreatment with apocynin or PEG-catalase in cirrhotic rats, the hydrogen peroxide level in the mesenteric arteriole was significantly decreased, and the dose-response curve of mesenteric arteriole to NE moved to the left with EC50 decreased. There was no significant change for the expression of α1 adrenergic receptor. However, the protein expression of β-arrestin-2 and its affinity with α1 adrenergic receptor were significantly decreased. The ROCK-1 activity and anti- Y-27632 inhibition in cirrhotic rats increased significantly with the protein expression unchanged. Such effects were not observed in tempol-treated group. Conclusion: The H2O2 decrease in mesenteric artery from rats with cirrhosis resulted in down regulation of the β-arrestin-2 expression and its binding ability with α1 adrenergic receptor, thereby affecting the agonist-induced ROCK activation and improving the contractile response in blood vessels. PMID:24719556

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

    PubMed

    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

  9. 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. PMID:25684443

  10. Autophagy-related Gene 7 (ATG7) and Reactive Oxygen Species/Extracellular Signal-regulated Kinase Regulate Tetrandrine-induced Autophagy in Human Hepatocellular Carcinoma*

    PubMed Central

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

    2012-01-01

    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. PMID:22927446

  11. A new algorithm for real-time optimal dispatch of active and reactive power generation retaining nonlinearity

    SciTech Connect

    Roy, L.; Rao, N.D.

    1983-04-01

    This paper presents a new method for optimal dispatch of real and reactive power generation which is based on cartesian coordinate formulation of economic dispatch problem and reclassification of state and control variables associated with generator buses. The voltage and power at these buses are classified as parametric and functional inequality constraints, and are handled by reduced gradient technique and penalty factor approach respectively. The advantage of this classification is the reduction in the size of the equality constraint model, leading to less storage requirement. The rectangular coordinate formulation results in an exact equality constraint model in which the coefficient matrix is real, sparse, diagonally dominant, smaller in size and need be computed and factorized once only in each gradient step. In addition, Lagragian multipliers are calculated using a new efficient procedure. A natural outcome of these features is the solution of the economic dispatch problem, faster than other methods available to date in the literature. Rapid and reliable convergence is an additional desirable characteristic of the method. Digital simulation results are presented on several IEEE test systems to illustrate the range of application of the method visa-vis the popular Dommel-Tinney (DT) procedure. It is found that the proposed method is more reliable, 3-4 times faster and requires 20-30 percent less storage compared to the DT algorithm, while being just as general. Thus, owing to its exactness, robust mathematical model and less computational requirements, the method developed in the paper is shown to be a practically feasible algorithm for on-line optimal power dispatch.

  12. 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.

  13. 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

  14. 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.

  15. Reactive Oxygen Species Differentially Regulate Bone Turnover in an Age-Specific Manner in Catalase Transgenic Female Mice.

    PubMed

    Alund, Alexander W; Mercer, Kelly E; Suva, Larry J; Pulliam, Casey F; Chen, Jin-Ran; Badger, Thomas M; Van Remmen, Holly; Ronis, Martin J J

    2016-07-01

    Chronic ethyl alcohol (EtOH) consumption results in reactive oxygen species (ROS) generation in bone and osteopenia due to increased bone resorption and reduced bone formation. In this study, transgenic C57Bl/6J mice overexpressing human catalase (TgCAT) were used to test whether limiting excess hydrogen peroxide would protect against EtOH-mediated bone loss. Micro-computed tomography analysis of the skeletons of 6-week-old female chow-fed TgCAT mice revealed a high bone mass phenotype with increased cortical bone area and thickness as well as significantly increased trabecular bone volume (P < 0.05). Six-week-old wild-type (WT) and TgCAT female mice were chow fed or pair fed (PF) liquid diets with or without EtOH, approximately 30% of calories, for 8 weeks. Pair feeding of WT had no demonstrable effect on the skeleton; however, EtOH feeding of WT mice significantly reduced cortical and trabecular bone parameters along with bone strength compared with PF controls (P < 0.05). In contrast, EtOH feeding of TgCAT mice had no effect on trabecular bone compared with PF controls. At 14 weeks of age, there was significantly less trabecular bone and cortical cross-sectional area in TgCAT mice than WT mice (P < 0.05), suggesting impaired normal bone accrual with age. TgCAT mice expressed less collagen1α and higher sclerostin mRNA (P < 0.05), suggesting decreased bone formation in TgCAT mice. In conclusion, catalase overexpression resulted in greater bone mass than in WT mice at 6 weeks and lower bone mass at 14 weeks. EtOH feeding induced significant reductions in bone architecture and strength in WT mice, but TgCAT mice were partially protected. These data implicate ROS signaling in the regulation of bone turnover in an age-dependent manner, and indicate that excess hydrogen peroxide generation contributes to alcohol-induced osteopenia. PMID:27189961

  16. Tyk2 negatively regulates adaptive Th1 immunity by mediating IL-10 signaling and promoting IFN-gamma-dependent IL-10 reactivation.

    PubMed

    Shaw, Michael H; Freeman, Gordon J; Scott, Mark F; Fox, Barbara A; Bzik, David J; Belkaid, Yasmine; Yap, George S

    2006-06-15

    The Jak, Tyk2, is activated in response to IL-12 and IFN-alphabeta and promotes IFN-gamma production by Th1-type CD4 cells. Mice deficient in Tyk2 function have been previously shown to be resistant to autoimmune arthritis and septic shock but are acutely susceptible to opportunistic pathogens such as Toxoplasma gondii. In this study, we show that Tyk2, in addition to mediating the biological effects of IL-12 and IFN-alphabeta, is an important regulator for the signaling and expression of the immunosuppressive cytokine IL-10. In the absence of Tyk2, Ag-reactive CD4 cells exhibit impaired IL-10 synthesis following rechallenge of T. gondii vaccine-primed mice. The impaired IL-10 reactivation leads to unopposed antimicrobial effector mechanisms which results in a paradoxically superior protection of immune Tyk2(-/-) mice against virulent T. gondii challenge. We further demonstrate that Tyk2 indirectly controls CD4 IL-10 reactivation by signaling for maximal IFN-gamma secretion. The unexpected role of IFN-gamma in mediating IL-10 reactivation by Th1 cells provides compelling evidence that conditions driving Th1 responses establish a negative feedback loop, which will ultimately lead to its autoregulation. Thus, Tyk2 can be viewed as a dual-function Jak, mediating both pro and anti-inflammatory cytokine responses. PMID:16751369

  17. 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.

  18. A novel current and voltage regulated energy discharge power supply 200 A, 600 V

    SciTech Connect

    Visser, A.

    1991-05-01

    The fast spill beam extracted from the 1000 GeV particle accelerator Fermi National Accelerator Laboratory requires two pulsed magnet and power supply systems to steer the beam to the designated experimental area. This beam steering requires a magnetic field integral of 4kGm per magnet for a duration of 4 msec at a rate of one shot per 5 seconds, and limited to 6 shots per 63 seconds. Each shot cannot last any longer than about 100 msec from start to finish. The magnetic field must be constant to within 1% during each 4 msec spill period. This paper describes an energy discharge type power supply and magnet that meet these requirements. This unique power supply has two regulators. One regulator preregulates the storage voltage and the other regulates the required peak current. The magnet and power supply design are interwoven to allow the use of easily available commercial parts for the power supply. Power supply and magnet design should always go hand in hand.

  19. 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

  20. Fragile X Protein is required for inhibition of insulin signaling and regulates glial-dependent neuroblast reactivation in the developing brain.

    PubMed

    Callan, Matthew A; Clements, Nicole; Ahrendt, Nicholas; Zarnescu, Daniela C

    2012-06-26

    Fragile X syndrome (FXS) is the most common form of inherited mental disability and known cause of autism. It is caused by loss of function for the RNA binding protein FMRP, which has been demonstrated to regulate several aspects of RNA metabolism including transport, stability and translation at synapses. Recently, FMRP has been implicated in neural stem cell proliferation and differentiation both in cultured neurospheres as well as in vivo mouse and fly models of FXS. We have previously shown that FMRP deficient Drosophila neuroblasts upregulate Cyclin E, prematurely exit quiescence, and overproliferate to generate on average 16% more neurons. Here we further investigate FMRP's role during early development using the Drosophila larval brain as a model. Using tissue specific RNAi we find that FMRP is required sequentially, first in neuroblasts and then in glia, to regulate exit from quiescence as measured by Cyclin E expression in the brain. Furthermore, we tested the hypothesis that FMRP controls brain development by regulating the insulin signaling pathway, which has been recently shown to regulate neuroblast exit from quiescence. Our data indicate that phosphoAkt, a readout of insulin signaling, is upregulated in dFmr1 brains at the time when FMRP is required in glia for neuroblast reactivation. In addition, dFmr1 interacts genetically with dFoxO, a transcriptional regulator of insulin signaling. Our results provide the first evidence that FMRP is required in vivo, in glia for neuroblast reactivation and suggest that it may do so by regulating the output of the insulin signaling pathway. This article is part of a Special Issue entitled: RNA-Binding Proteins. PMID:22513101

  1. 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...

  2. 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.

  3. 75 FR 29531 - Frequency Regulation Compensation in the Organized Wholesale Power Markets; Supplemental Notice...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-26

    ... 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... the April 27 Notice, the conference will provide a forum to consider issues related to...

  4. 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.

  5. Regulated-current dc power supply for gaseous-discharge lamps

    NASA Technical Reports Server (NTRS)

    Freeman, W.; Huguenin, D.

    1970-01-01

    Controlled current source having a high output resistance feeds continuous-flow hydrogen lamps in vacuum-ultraviolet photometric equipment. The power supply, also used with low-pressure sealed lamps, has a short recovery time and smooth regulation without overshoot.

  6. 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.

  7. 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. PMID:25243199

  8. 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

  9. Self-regulating MBE growth of stoichiometric BaSnO3 films via reactive radical mechanism

    NASA Astrophysics Data System (ADS)

    Prakash, Abhinav; Dewey, John; Yun, Hwanhui; Jeong, Jong Seok; Mkhoyan, K. Andre; Jalan, Bharat

    Growth of thin films comprising of element with low oxidation potential such as Sn often requires reactive oxidants such as ozone or high-pressure oxygen plasma. By utilizing the chemistry of highly reactive radical of Sn, we will present on the growth of phase-pure, epitaxial BaSnO3 films using a hybrid molecular beam epitaxy (MBE) approach with scalable growth rates. The notable finding was that Sn radicals are very reactive to yield phase-pure BaSnO3 films even in molecular oxygen. In this approach, we use hexamethylditin (HMDT) as a tin source, a solid effusion cell for Ba and either molecular oxygen or an rf oxygen plasma source. Phase-pure BaSnO3 films were grown at 900 0C, and oxygen pressure of 5x10-6 Torr as a function Sn:Ba ratio. In-situ time-dependent RHEED intensity oscillations were observed establishing a layer-by-layer growth mode and a critical thickness of ~1 nm for strain relaxation. Rutherford backscattering spectrometry and lattice constant determined using high-resolution X-ray diffraction was used to optimize cation stoichiometry. ``MBE growth window'' was identified where films show bulk-like lattice parameter (4.116 Å) over a wide-range of cation flux ratios. A correlation between RHEED patterns, stoichiometry, and surface morphology was established This work is supported primarily by NSF (DMR-1410888).

  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. PMID:25816783

  11. 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

  12. Ethylene Response Factor TERF1, Regulated by ETHYLENE-INSENSITIVE3-like Factors, Functions in Reactive Oxygen Species (ROS) Scavenging in Tobacco (Nicotiana tabacum L.).

    PubMed

    Zhang, Hongbo; Li, Ang; Zhang, Zhijin; Huang, Zejun; Lu, Pingli; Zhang, Dingyu; Liu, Xinmin; Zhang, Zhong-Feng; Huang, Rongfeng

    2016-01-01

    The phytohormone ethylene plays a crucial role in the production and accumulation of reactive oxygen species (ROS) in plants under stress conditions. Ethylene response factors (ERFs) are important ethylene-signaling regulators functioning in plant defense responses against biotic and abiotic stresses. However, the roles of ERFs during plant adapting to ROS stress have not yet been well documented. Our studies previously reported that a tomato ERF transcription factor TERF1 functions in the regulation of plant ethylene responses and stress tolerance. Here, we report our findings regarding the roles of TERF1 in ROS scavenging. In this study, we revealed that the transcription of TERF1 is regulated by upstream EIN3-like (EIN3, ethylene-insensitive 3) regulators LeEIL3 and LeEIL4 in tomato (Solanum lycopersicum), and is also inducible by exogenous applied ROS-generating reagents. Ectopic expression of TERF1 in tobacco promoted the expression of genes involved in oxidative stress responses, including carbonic anhydrase functioning in hypersensitive defense, catalase and glutathione peroxidase catalyzing oxidative reactions, and GDP-D-mannose pyrophosphorylase functioning in ascorbic acid biosynthesis, reduced the ROS content induced by ethylene treatment, and enhanced stress tolerance of tobacco seedlings to hydrogen peroxide (H2O2). Cumulatively, these findings suggest that TERF1 is an ethylene inducible factor regulating ROS scavenging during stress responses. PMID:27435661

  13. Ethylene Response Factor TERF1, Regulated by ETHYLENE-INSENSITIVE3-like Factors, Functions in Reactive Oxygen Species (ROS) Scavenging in Tobacco (Nicotiana tabacum L.)

    PubMed Central

    Zhang, Hongbo; Li, Ang; Zhang, Zhijin; Huang, Zejun; Lu, Pingli; Zhang, Dingyu; Liu, Xinmin; Zhang, Zhong-Feng; Huang, Rongfeng

    2016-01-01

    The phytohormone ethylene plays a crucial role in the production and accumulation of reactive oxygen species (ROS) in plants under stress conditions. Ethylene response factors (ERFs) are important ethylene-signaling regulators functioning in plant defense responses against biotic and abiotic stresses. However, the roles of ERFs during plant adapting to ROS stress have not yet been well documented. Our studies previously reported that a tomato ERF transcription factor TERF1 functions in the regulation of plant ethylene responses and stress tolerance. Here, we report our findings regarding the roles of TERF1 in ROS scavenging. In this study, we revealed that the transcription of TERF1 is regulated by upstream EIN3-like (EIN3, ethylene-insensitive 3) regulators LeEIL3 and LeEIL4 in tomato (Solanum lycopersicum), and is also inducible by exogenous applied ROS-generating reagents. Ectopic expression of TERF1 in tobacco promoted the expression of genes involved in oxidative stress responses, including carbonic anhydrase functioning in hypersensitive defense, catalase and glutathione peroxidase catalyzing oxidative reactions, and GDP-D-mannose pyrophosphorylase functioning in ascorbic acid biosynthesis, reduced the ROS content induced by ethylene treatment, and enhanced stress tolerance of tobacco seedlings to hydrogen peroxide (H2O2). Cumulatively, these findings suggest that TERF1 is an ethylene inducible factor regulating ROS scavenging during stress responses. PMID:27435661

  14. 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

  15. Sexual Preferences in Nutrient Utilization Regulate Oxygen Consumption and Reactive Oxygen Species Generation in Schistosoma mansoni: Potential Implications for Parasite Redox Biology.

    PubMed

    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

  16. CYCLIN H;1 regulates drought stress responses and blue light-induced stomatal opening by inhibiting reactive oxygen species accumulation in Arabidopsis.

    PubMed

    Zhou, Xiao Feng; Jin, Yin Hua; Yoo, Chan Yul; Lin, Xiao-Li; Kim, Woe-Yeon; Yun, Dae-Jin; Bressan, Ray A; Hasegawa, Paul M; Jin, Jing Bo

    2013-06-01

    Arabidopsis (Arabidopsis thaliana) CYCLIN-DEPENDENT KINASE Ds (CDKDs) phosphorylate the C-terminal domain of the largest subunit of RNA polymerase II. Arabidopsis CYCLIN H;1 (CYCH;1) interacts with and activates CDKDs; however, the physiological function of CYCH;1 has not been determined. Here, we report that CYCH;1, which is localized to the nucleus, positively regulates blue light-induced stomatal opening. Reduced-function cych;1 RNA interference (cych;1 RNAi) plants exhibited a drought tolerance phenotype. CYCH;1 is predominantly expressed in guard cells, and its expression was substantially down-regulated by dehydration. Transpiration of intact leaves was reduced in cych;1 RNAi plants compared with the wild-type control in light but not in darkness. CYCH;1 down-regulation impaired blue light-induced stomatal opening but did not affect guard cell development or abscisic acid-mediated stomatal closure. Microarray and real-time polymerase chain reaction analyses indicated that CYCH;1 did not regulate the expression of abscisic acid-responsive genes or light-induced stomatal opening signaling determinants, such as MYB60, MYB61, Hypersensitive to red and blue1, and Protein phosphatase7. CYCH;1 down-regulation induced the expression of redox homeostasis genes, such as LIPOXYGENASE3 (LOX3), LOX4, ARABIDOPSIS GLUTATHIONE PEROXIDASE 7 (ATGPX7), EARLY LIGHT-INDUCIBLE PROTEIN1 (ELIP1), and ELIP2, and increased hydrogen peroxide production in guard cells. Furthermore, loss-of-function mutations in CDKD;2 or CDKD;3 did not affect responsiveness to drought stress, suggesting that CYCH;1 regulates the drought stress response in a CDKD-independent manner. We propose that CYCH;1 regulates blue light-mediated stomatal opening by controlling reactive oxygen species homeostasis. PMID:23656895

  17. 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.

  18. 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. PMID:26428066

  19. 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 Central

    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

    2015-01-01

    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. PMID:26428066

  20. 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...

  1. Large lead/acid batteries for frequency regulation, load levelling and solar power applications

    NASA Astrophysics Data System (ADS)

    Wagner, R.

    Lead/acid batteries are suitable for a multitude of utility applications. This paper presents some examples where large lead/acid batteries have been used for frequency regulation, load levelling and solar power applications. The operational experiences are given together with a discussion about the design and technical specialities of these batteries. In 1986, a 17 MW/14 MWh battery was installed at BEWAG in Berlin which, at that time, was the largest lead/acid battery in the world. Designed to strengthen Berlin's 'island' system, it was used since the beginning of 1987 for frequency regulation and spinning reserve. In December 1993, when Berlin was connected to the electricity grid, frequency regulation was no longer required but the battery was still used for spinning reserve. For many years, the industrial battery plant of Hagen in Soest has used a large lead/acid battery for load levelling. The experience gained during more than ten years shows that load levelling and peak shaving can be a marked benefit for customers and utilities with regard to reducing their peak demand. In the summer of 1992, a 216 V and 2200 Ah lead/acid battery with positive tubular plates and gelled electrolyte was installed at a solar power plant in Flanitzhutte, a small village in the south of Germany which is not connected to the electricity grid. A report is given of the first years of use and includes a discussion about the best charge strategy for such gel batteries when used for solar power applications.

  2. 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

  3. Preparation of hydrogenated diamond-like carbon films by reactive Ar/CH4 high power impulse magnetron sputtering with negative pulse voltage

    NASA Astrophysics Data System (ADS)

    Kimura, Takashi; Kamata, Hikaru

    2015-09-01

    High power impulse magnetron sputtering (HiPIMS) has been attracted, because sputtered target species are highly ionized. High densities of active species such as radical ions and neutral radicals can be also achieved owing to high density reactive HiPIMS plasmas. We investigate properties of hydrogenated diamond-like carbon films prepared by reactive HiPIMS of Ar/CH4 gas mixture. The properties of the films strongly depend on the plasma compositions and the kinetic energy of the carbon-containing ions which can enter into the films. The film preparation is performed at an average power of 60 W and a repetition frequency of 110 Hz, changing CH4 fraction up to 15%. 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 36 A. A negative pulse voltage is applied to the substrates for about 10 μs after the target voltage changed from about -600 V to 0 V. The structural properties are characterized by Raman spectroscopy and nano-indentation method. Film hardness strongly depends on the magnitude of negative pulse voltage. By adjusting the magnitude of negative voltage, the film hardness ranges between about 10 and 22 GPa. This work is partially supported by JSPS KAKENHI Grant Number 26420230.

  4. 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.

  5. 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.

  6. Regulation of reactive oxygen species-mediated abscisic acid signaling in guard cells and drought tolerance by glutathione

    PubMed Central

    Munemasa, Shintaro; Muroyama, Daichi; Nagahashi, Hiroki; Nakamura, Yoshimasa; Mori, Izumi C.; Murata, Yoshiyuki

    2013-01-01

    The phytohormone abscisic acid (ABA) induces stomatal closure in response to drought stress, leading to reduction of transpirational water loss. A thiol tripeptide glutathione (GSH) is an important regulator of cellular redox homeostasis in plants. Although it has been shown that cellular redox state of guard cells controls ABA-mediated stomatal closure, roles of GSH in guard cell ABA signaling were largely unknown. Recently we demonstrated that GSH functions as a negative regulator of ABA signaling in guard cells. In this study we performed more detailed analyses to reveal how GSH regulates guard cell ABA signaling using the GSH-deficient Arabidopsis mutant cad2-1. The cad2-1 mutant exhibited reduced water loss from rosette leaves. Whole-cell current recording using patch clamp technique revealed that the cad2-1 mutation did not affect ABA regulation of S-type anion channels. We found enhanced activation of Ca2+ permeable channels by hydrogen peroxide (H2O2) in cad2-1 guard cells. The cad2-1 mutant showed enhanced H2O2-induced stomatal closure and significant increase of ROS accumulation in whole leaves in response to ABA. Our findings provide a new understanding of guard cell ABA signaling and a new strategy to improve plant drought tolerance. PMID:24312112

  7. 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

  8. Reactive oxygen species (ROS) production triggered by prostaglandin D2 (PGD2) regulates lactate dehydrogenase (LDH) expression/activity in TM4 Sertoli cells.

    PubMed

    Rossi, Soledad P; Windschüttl, Stefanie; Matzkin, María E; Rey-Ares, Verónica; Terradas, Claudio; Ponzio, Roberto; Puigdomenech, Elisa; Levalle, Oscar; Calandra, Ricardo S; Mayerhofer, Artur; Frungieri, Mónica B

    2016-10-15

    Reactive oxygen species (ROS) regulate testicular function in health and disease. We previously described a prostaglandin D2 (PGD2) system in Sertoli cells. Now, we found that PGD2 increases ROS and hydrogen peroxide (H2O2) generation in murine TM4 Sertoli cells, and also induces antioxidant enzymes expression suggesting that defense systems are triggered as an adaptive stress mechanism that guarantees cell survival. ROS and specially H2O2 may act as second messengers regulating signal transduction pathways and gene expression. We describe a stimulatory effect of PGD2 on lactate dehydrogenase (LDH) expression via DP1/DP2 receptors, which is prevented by the antioxidant N-acetyl-L-cysteine and the PI3K/Akt pathway inhibitor LY 294002. PGD2 also enhances Akt and CREB/ATF-1 phosphorylation. Our results provide evidence for a role of PGD2 in the regulation of the oxidant/antioxidant status in Sertoli cells and, more importantly, in the modulation of LDH expression which takes place through ROS generation and the Akt-CREB/ATF-1 pathway. PMID:27329155

  9. Platycodin D induces reactive oxygen species-mediated apoptosis signal-regulating kinase 1 activation and endoplasmic reticulum stress response in human breast cancer cells.

    PubMed

    Yu, Ji Sun; Kim, An Keun

    2012-08-01

    Platycodin D (PD), a natural compound found in Platycodon grandiflorum, induces apoptotic cell death in various carcinoma cells. One mechanism of PD-mediated cell death is by activation of mitogen-activated protein kinases, as suggested in a recent report. In this study, we further examined upstream signal pathways and the relationship between these signals and reactive oxygen species (ROS). Using immunoblotting assays, we found that PD activated apoptosis signal-regulating kinase 1 (ASK1) through phosphorylation of ASK1 at threonine and dephosphorylation of ASK1 at serine. We also showed that PD caused activation of the endoplasmic reticulum (ER) stress response. This was supported by observations showing that treatment with PD induces phosphorylation of PKR-like ER kinase (PERK) and eukaryotic initiation factor 2 α (eIF 2α), up-regulating expression of glucose-regulated protein 78/immunoglobulin heavy chain binding protein (GRP78/Bip) and CCAAT/enhancer-binding protein homologous protein/growth arrest and DNA damage-inducible gene 153 (CHOP/GADD153) and activation of caspase-4. Furthermore, PD-induced ASK1 and ER stress responses were inhibited by the antioxidant N-acetyl-l-cysteine. These results suggest that ROS play a critical role for activation of ASK1 and ER stress in PD-treated cancer cells. PMID:22784044

  10. Requirement of NOX2 and Reactive Oxygen Species for Efficient RIG-I-Mediated Antiviral Response through Regulation of MAVS Expression

    PubMed Central

    Fink, Karin; Martel, Alexis; Jouan, Loubna; Nzengue, Yves; Lamarre, Daniel; Vande Velde, Christine; Grandvaux, Nathalie

    2010-01-01

    The innate immune response is essential to the host defense against viruses, through restriction of virus replication and coordination of the adaptive immune response. Induction of antiviral genes is a tightly regulated process initiated mainly through sensing of invading virus nucleic acids in the cytoplasm by RIG-I like helicases, RIG-I or Mda5, which transmit the signal through a common mitochondria-associated adaptor, MAVS. Although major breakthroughs have recently been made, much remains unknown about the mechanisms that translate virus recognition into antiviral genes expression. Beside the reputed detrimental role, reactive oxygen species (ROS) act as modulators of cellular signaling and gene regulation. NADPH oxidase (NOX) enzymes are a main source of deliberate cellular ROS production. Here, we found that NOX2 and ROS are required for the host cell to trigger an efficient RIG-I-mediated IRF-3 activation and downstream antiviral IFNβ and IFIT1 gene expression. Additionally, we provide evidence that NOX2 is critical for the expression of the central mitochondria-associated adaptor MAVS. Taken together these data reveal a new facet to the regulation of the innate host defense against viruses through the identification of an unrecognized role of NOX2 and ROS. PMID:20532218

  11. 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

  12. Reactive oxygen species regulate ERBB2 and ERBB3 expression via miR-199a/125b and DNA methylation

    PubMed Central

    He, Jun; Xu, Qing; Jing, Yi; Agani, Faton; Qian, Xu; Carpenter, Richard; Li, Qi; Wang, Xin-Ru; Peiper, Stephen S; Lu, Zhimin; Liu, Ling-Zhi; Jiang, Bing-Hua

    2012-01-01

    Overexpression of ERBB2 or ERBB3 is associated with cancer development and poor prognosis. In this study, we show that reactive oxygen species (ROS) induce both ERBB2 and ERBB3 expression in vitro and in vivo. We also identify that miR-199a and miR-125b target ERBB2 and/or ERBB3 in ovarian cancer cells, and demonstrate that ROS inhibit miR-199a and miR-125b expression through increasing the promoter methylation of the miR-199a and miR-125b genes by DNA methyltransferase 1. These findings reveal that ERBB2 and ERBB3 expression is regulated by ROS via miR-199a and miR-125b downregulation and DNA hypermethylation. PMID:23146892

  13. Regulation of Cathepsin G Reduces the Activation of Proinsulin-Reactive T Cells from Type 1 Diabetes Patients

    PubMed Central

    Zou, Fang; Schäfer, Nadja; Palesch, David; Brücken, Ruth; Beck, Alexander; Sienczyk, Marcin; Kalbacher, Hubert; Sun, ZiLin; Boehm, Bernhard O.; Burster, Timo

    2011-01-01

    Autoantigenic peptides resulting from self-proteins such as proinsulin are important players in the development of type 1 diabetes mellitus (T1D). Self-proteins can be processed by cathepsins (Cats) within endocytic compartments and loaded to major histocompatibility complex (MHC) class II molecules for CD4+ T cell inspection. However, the processing and presentation of proinsulin by antigen-presenting cells (APC) in humans is only partially understood. Here we demonstrate that the processing of proinsulin by B cell or myeloid dendritic cell (mDC1)-derived lysosomal cathepsins resulted in several proinsulin-derived intermediates. These intermediates were similar to those obtained using purified CatG and, to a lesser extent, CatD, S, and V in vitro. Some of these intermediates polarized T cell activation in peripheral blood mononuclear cells (PBMC) from T1D patients indicative for naturally processed T cell epitopes. Furthermore, CatG activity was found to be elevated in PBMC from T1D patients and abrogation of CatG activity resulted in functional inhibition of proinsulin-reactive T cells. Our data suggested the notion that CatG plays a critical role in proinsulin processing and is important in the activation process of diabetogenic T cells. PMID:21850236

  14. Reactive oxygen species regulate leaf pulvinus abscission zone cell separation in response to water-deficit stress in cassava

    PubMed Central

    Liao, Wenbin; Wang, Gan; Li, Yayun; Wang, Bin; Zhang, Peng; Peng, Ming

    2016-01-01

    Cassava (Manihot esculenta Crantz) plant resists water-deficit stress by shedding leaves leading to adaptive water-deficit condition. Transcriptomic, physiological, cellular, molecular, metabolic, and transgenic methods were used to study the mechanism of cassava abscission zone (AZ) cell separation under water-deficit stress. Microscopic observation indicated that AZ cell separation initiated at the later stages during water-deficit stress. Transcriptome profiling of AZ suggested that differential expression genes of AZ under stress mainly participate in reactive oxygen species (ROS) pathway. The key genes involved in hydrogen peroxide biosynthesis and metabolism showed significantly higher expression levels in AZ than non-separating tissues adjacent to the AZ under stress. Significantly higher levels of hydrogen peroxide correlated with hydrogen peroxide biosynthesis related genes and AZ cell separation was detected by microscopic observation, colorimetric detection and GC-MS analyses under stress. Co-overexpression of the ROS-scavenging proteins SOD and CAT1 in cassava decreased the levels of hydrogen peroxide in AZ under water-deficit stress. The cell separation of the pulvinus AZ also delayed in co-overexpression of the ROS-scavenging proteins SOD and CAT1 plants both in vitro and at the plant level. Together, the results indicated that ROS play an important regulatory role in the process of cassava leaf abscission under water-deficit stress. PMID:26899473

  15. Reactive oxygen species regulate leaf pulvinus abscission zone cell separation in response to water-deficit stress in cassava.

    PubMed

    Liao, Wenbin; Wang, Gan; Li, Yayun; Wang, Bin; Zhang, Peng; Peng, Ming

    2016-01-01

    Cassava (Manihot esculenta Crantz) plant resists water-deficit stress by shedding leaves leading to adaptive water-deficit condition. Transcriptomic, physiological, cellular, molecular, metabolic, and transgenic methods were used to study the mechanism of cassava abscission zone (AZ) cell separation under water-deficit stress. Microscopic observation indicated that AZ cell separation initiated at the later stages during water-deficit stress. Transcriptome profiling of AZ suggested that differential expression genes of AZ under stress mainly participate in reactive oxygen species (ROS) pathway. The key genes involved in hydrogen peroxide biosynthesis and metabolism showed significantly higher expression levels in AZ than non-separating tissues adjacent to the AZ under stress. Significantly higher levels of hydrogen peroxide correlated with hydrogen peroxide biosynthesis related genes and AZ cell separation was detected by microscopic observation, colorimetric detection and GC-MS analyses under stress. Co-overexpression of the ROS-scavenging proteins SOD and CAT1 in cassava decreased the levels of hydrogen peroxide in AZ under water-deficit stress. The cell separation of the pulvinus AZ also delayed in co-overexpression of the ROS-scavenging proteins SOD and CAT1 plants both in vitro and at the plant level. Together, the results indicated that ROS play an important regulatory role in the process of cassava leaf abscission under water-deficit stress. PMID:26899473

  16. 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

  17. 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.

  18. Multidrug resistance-associated protein 3 confers resistance to chemoradiotherapy for rectal cancer by regulating reactive oxygen species and caspase-3-dependent apoptotic pathway.

    PubMed

    Yu, Zhiqi; Zhang, Chang; Wang, Hao; Xing, Junjie; Gong, Haifeng; Yu, Enda; Zhang, Wei; Zhang, Xiaoqing; Cao, Guangwen; Fu, Chuangang

    2014-10-28

    This study aimed to clarify the role of multidrug resistance-associated protein 3 (MRP3) in resistance to neoadjuvant chemoradiotherapy and long-term prognosis of advanced rectal cancer. Immunohistochemistry was used to measure MRP3 expression in biopsy specimens of 144 stage II-III rectal cancer patients who received preoperative chemoradiotherapy. The effect of MRP3 expression on short-term pathological response and postoperative long-term prognosis were assessed using the Cox proportional hazards model. Short interfering RNAs targeting MRP3 were synthesized and used to transfect human colorectal carcinoma cell lines. The effect of MRP3 down-regulation on cell proliferation and apoptosis in response to 5-fluorouracil and/or irradiation were examined in vitro and in xenograft mouse models, respectively. The content of intracellular reactive oxygen species and the activity of caspase-3-dependent apoptotic pathway in response to irradiation were further evaluated. High expression (immunoreactive score > 6) of MRP3 significantly predicted poor pathological response to chemoradiotherapy (tumor regression grade ≤ 2 vs. ≥3, p = 0.002) in univariate analysis and unfavorable long-term prognosis (5-year overall survival: HR = 1.612, 95% CI, 1.094-2.375, p = 0.016; 5-year disease-free survival: HR = 1.513, 95% CI, 1.041-2.200, p = 0.030) in multivariate Cox analysis. MRP3 down-regulation significantly increased 5-fluorouracil or irradiation-induced cell apoptosis and attenuated tumor growth following irradiation in animal models. MRP3 inhibition significantly reduced intracellular reactive oxygen species exporting from cells following irradiation, and increased expression of cleaved poly ADP-ribose polymerase and caspase-3. Aberrant expression of MRP3 in rectal cancer confers chemo-radioresistance. MRP3 might be a predictive factor and an attractive target in treating advanced rectal cancer. PMID:25088576

  19. 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. PMID:19207807

  20. A Role for the Androgen Metabolite, 5α-Androstane-3β,17β-Diol, in Modulating Oestrogen Receptor β-Mediated Regulation of Hormonal Stress Reactivity

    PubMed Central

    Handa, R. J.; Weiser, M. J.; Zuloaga, D. G.

    2009-01-01

    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)β, whereas oestrogen acts predominantly through ERα. Thus, we examined the hypothesis that, in males, testosterone suppresses HPA function via an androgen metabolite that binds ERβ. Clues to the neurobiological mechanisms underlying such a novel action can be gleaned from studies showing extensive colocalisation of ERβ in oxytocin-containing cells of the PVN. Hence, in this review, we address the possibility that testosterone inhibits HPA reactivity by metabolising to 5α-androstane-3β,17β-diol, a compound that binds ERβ and regulates oxytocin containing neurones of the PVN. These findings suggest a re-evaluation of studies examining pathways for androgen receptor signalling. PMID:19207807

  1. Sodium nitrite enhances generation of reactive oxygen species that decrease antioxidant power and inhibit plasma membrane redox system of human erythrocytes.

    PubMed

    Ansari, Fariheen Aisha; Mahmood, Riaz

    2016-08-01

    Nitrite/nitrate salts are used in fertilizers and as food preservatives. Human exposure to high levels of nitrite results in its uptake and subsequent entry into blood where it can interact with erythrocytes. We show that treatment of human erythrocytes with sodium nitrite (NaNO2 ) results in a dose-dependent increase in the production of reactive oxygen species. This was accompanied by a decrease in the antioxidant power which lowered the free radical quenching and metal-reducing ability. NaNO2 treatment also inhibited plasma membrane redox system (PMRS) of erythrocytes. These changes increase the susceptibility of erythrocytes to oxidative damage, decrease the antioxidant power of whole blood, and can be a major cause of nitrite-induced cellular toxicity. PMID:27214747

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

    PubMed

    Park, Youngjin; Stanley, David W; Kim, Yonggyun

    2015-08-01

    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 eicosanoids mediate ROS production by activating NADPH-dependent oxidase (NOX) and tested the idea in the model insect, Spodoptera exigua. A NOX gene (we named SeNOX4) was identified and cloned, yielding a full open reading frame encoding 547 amino acid residues with a predicted molecular weight of 63,410Da and an isoelectric point at 9.28. A transmembrane domain and a large intracellular domain containing NADPH and FAD-binding sites were predicted. Phylogenetic analysis indicated SeNOX4 clusters with other NOX4 genes. SeNOX4 was expressed in all life stages except eggs, and exclusively in hemocytes. Bacterial challenge and, separately, arachidonic acid (AA, a precursor of eicosanoid biosynthesis) injection increased its expression. The internalization step was assessed by counting hemocytes engulfing fluorescence-labeled bacteria. The phagocytic behavior was inhibited by dsRNA suppression of SeNOX4 expression and, separately by dexamethasone (DEX, a specific inhibitor of eicosanoid biosynthesis) treatments. However, injecting AA to dsSeNOX4-treated larvae did not rescue the phagocytic activity. Hemocytic ROS production increased following bacterial challenge, which was sharply reduced in dsSeNOX4-treated, and separately, in DEX-treated larvae. AA partially reversed the suppressed ROS production in dsSeNOX4-treated larvae. Treating larvae with either the ROS-suppressing dsSeNOX4 construct or DEX rendered experimental larvae unable to inhibit bacterial proliferation in their hemocoels. We infer that eicosanoids mediate ROS production during phagocytosis by inducing expression of SeNOX4. PMID:26071791

  3. Reactive oxygen species promotes cellular senescence in normal human epidermal keratinocytes through epigenetic regulation of p16(INK4a.).

    PubMed

    Sasaki, Mina; Kajiya, Hiroshi; Ozeki, Satoru; Okabe, Koji; Ikebe, Tetsuro

    2014-09-26

    Reactive oxygen species (ROS) can cause severe damage to DNA, proteins and lipids in normal cells, contributing to carcinogenesis and various pathological conditions. While cellular senescence arrests the early phase of cell cycle without any detectable telomere loss or dysfunction. ROS is reported to contribute to induction of cellular senescence, as evidence by its premature onset upon treatment with antioxidants or inhibitors of cellular oxidant scavengers. Although cellular senescence is known to be implicated in tumor suppression, it remains unknown whether ROS initially contributed to be cellular senescence in normal human epidermal keratinocytes (NHEK) and their malignant counterparts. To clarify whether ROS induce cellular senescence in NHEKs, we examined the effect of hydrogen peroxide (H2O2) on the expression of cellular senescence-associated molecules in NHEKs, compared to in squamous carcinoma cells (SCCs). Hydrogen peroxide increased the number of cells positive in senescence associated-β-galactosidase (SA-β-Gal) activity in NHEKs, but not SCCs. The expression of cyclin-dependent kinase (CDK) inhibitors, especially p16(INK4a) was upregulated in NHEKs treated with H2O2. Interestingly, H2O2 suppressed the methylation of p16(INK4a), promoter region in NHEKs, but not in SCCs. Hydrogen peroxide also suppressed the expression of phosphorylated Rb and CDK4, resulting in arrest in G0/G1 phase in NHEKs, but not SCCs. Our results indicate that the ROS-induced cellular senescence in NHEKs was caused by the upregulation p16(INK4a) through demethylation in its promoter region, which is not detected in SCCs, suggesting that ROS-induced cellular senescence contributes to tumor suppression of NHEKs. PMID:25181340

  4. NO contributes to abnormal vascular calcium regulation and reactivity induced by peritonitis-associated septic shock in rats.

    PubMed

    Chen, Shiu-Jen; Li, Shaio-Yun; Shih, Chih-Chin; Liao, Mei-Huei; Wu, Chin-Chen

    2010-05-01

    Calcium plays an important role in determining vascular smooth muscle tone. Norepinephrine (NE)-induced vascular contraction contains two components: 1) Ca2+ release from the sarcoplasmic reticulum as the fast phase and 2) Ca2+ influx via a voltage-dependent calcium channel as the slow phase. This study used functional isometric tension recording to evaluate mediators contributing to abnormal NE-induced Ca2+ handling and reactivity in isolated thoracic aortas from septic rats. Sepsis was induced by cecal ligation and puncture (CLP), and thoracic aortas were removed at 18 h after CLP. Our results showed that rats that received CLP for 18 h manifested severe hypotension and vascular hyporeactivity to NE in vivo. This vascular hyporeactivity to NE was also observed in the aorta obtained from CLP-induced sepsis rat. Both the fast and slow phases of NE-induced contraction were reduced in aortas from sepsis rats. To clarify what possible mediators contribute to the abnormal Ca2+ handling in aortas from sepsis animals, inhibitors of Ca2+ channel and release were used. Inhibition by 2-aminoethoxy-diphenyl borane, ryanodine, and cyclopiazonic acid of the NE-induced contraction in Ca2+-free solution was greater in the aorta from sepsis rats and inhibitions of cyclopiazonic acid and ryanodine, but not of 2-aminoethoxy-diphenyl borane, were attenuated by NOS inhibitor N[omega]-nitro-l-arginine methyl ester. In addition, the attenuation of NE-induced contraction by nifedipine in the aorta was also greater in the CLP group. Our results suggest that abnormal NE-induced Ca2+ handling associated with vascular hyporeactivity in the CLP-induced sepsis is caused by a major decrease in sarcoplasmic reticulum function and a minor impairment of voltage-dependent Ca2+ channels on membrane to Ca2+ handling, at least, in the aorta, and this could be attributed to an overproduction of NO in sepsis. PMID:19749606

  5. 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. PMID:25854793

  6. 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

  7. Avicin D: a protein reactive plant isoprenoid dephosphorylates Stat 3 by regulating both kinase and phosphatase activities.

    PubMed

    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

  8. 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.

  9. The dark side of ZNF217, a key regulator of tumorigenesis with powerful biomarker value

    PubMed Central

    Cohen, Pascale A.; Donini, Caterina F.; Nguyen, Nhan T.; Lincet, Hubert; Vendrell, Julie A.

    2015-01-01

    The recently described oncogene ZNF217 belongs to a chromosomal region that is frequently amplified in human cancers. Recent findings have revealed that alternative mechanisms such as epigenetic regulation also govern the expression of the encoded ZNF217 protein. Newly discovered molecular functions of ZNF217 indicate that it orchestrates complex intracellular circuits as a new key regulator of tumorigenesis. In this review, we focus on recent research on ZNF217-driven molecular functions in human cancers, revisiting major hallmarks of cancer and highlighting the downstream molecular targets and signaling pathways of ZNF217. We also discuss the exciting translational medicine investigating ZNF217 expression levels as a new powerful biomarker, and ZNF217 as a candidate target for future anti-cancer therapies. PMID:26431164

  10. Peak power and blade loads on stall-regulated rotors as influenced by different airfoil families

    SciTech Connect

    Tangler, J.L.; Tu, P.K.C.

    1988-08-01

    At the Solar Energy Research Institute (SERI), new airfoils have been developed to help improve the performance and economics of horizontal-axis wind turbines (HAWTS). The objective of this study was to compare the performance characteristics of one of these airfoil families to other commonly used airfoil series for a typical three-bladed, stall-regulated HAWT. The traditional airfoil series chosen for comparison with SERI's new thin airfoil family were the NACA 23XXX, NACA 44XX, and NASA LS(1). The Micon 110 wind turbine was chosen because it is a typical three-bladed, stall-regulated rigid rotor system. The performance characteristics of the different airfoil series were derived analytically using the Eppler airfoil design code in the analysis mode. On a relative basis, this approach to comparing airfoils was considered more accurate than using airfoil performance characteristics based on wind-tunnel test data. After generating the performance characteristics for each airfoil series, the subsequent rotor performance and blade loads were calculated using SERI's PROPSH computer code. Resulting annual energy output, which is dependent on the wind-speed distribution, was calculated using SERI's Systems Engineering and Analysis Computer Code (SEACC). The results of the study show that fixed-wing airfoils generally result in excessive peak power for stall regulated, rigid rotors. By operating the wind turbine at a less desirable blade pitch angle, peak power can be reduced at the expense of higher mean blade loads and lower annual energy output. In contrast, the thin airfoil family was designed to reduce peak power at optimum blade pitch to minimize blade loads and maximize annual energy output. 7 refs., 12 figs.

  11. Analysis, design, and control of a transcutaneous power regulator for artificial hearts.

    PubMed

    Qianhong Chen; Siu Chung Wong; Tse, C K; Xinbo Ruan

    2009-02-01

    Based on a generic transcutaneous transformer model, a remote power supply using a resonant topology for use in artificial hearts is analyzed and designed for easy controllability and high efficiency. The primary and secondary windings of the transcutaneous transformer are positioned outside and inside the human body, respectively. In such a transformer, the alignment and gap may change with external positioning. As a result, the coupling coefficient of the transcutaneous transformer is also varying, and so are the two large leakage inductances and the mutual inductance. Resonant-tank circuits with varying resonant-frequency are formed from the transformer inductors and external capacitors. For a given range of coupling coefficients, an operating frequency corresponding to a particular coupling coefficient can be found, for which the voltage transfer function is insensitive to load. Prior works have used frequency modulation to regulate the output voltage under varying load and transformer coupling. The use of frequency modulation may require a wide control frequency range which may extend well above the load insensitive frequency. In this paper, study of the input-to-output voltage transfer function is carried out, and a control method is proposed to lock the switching frequency at just above the load insensitive frequency for optimized efficiency at heavy loads. Specifically, operation at above resonant of the resonant circuits is maintained under varying coupling-coefficient. Using a digital-phase-lock-loop (PLL), zero-voltage switching is achieved in a full-bridge converter which is also programmed to provide output voltage regulation via pulsewidth modulation (PWM). A prototype transcutaneous power regulator is built and found to to perform excellently with high efficiency and tight regulation under variations of the alignment or gap of the transcutaneous transformer, load and input voltage. PMID:23853160

  12. 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.

  13. 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.

  14. 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.

  15. Study on Reactive Automatic Compensation System Design

    NASA Astrophysics Data System (ADS)

    Zhe, Sun; Qingyang, Liang; Peiqing, Luo; Chenfei, Zhang

    At present, low-voltage side of transformer is public in urban distribution network, as inductive load of household appliances is increasing, the power factor decreased, this lead to a large loss of public transformer low voltage side, the supply voltage indicators can not meet user's requirements. Therefore, the design of reactive power compensation system has become another popular research. This paper introduces the principle of reactive power compensation, analyzes key technologies of reactive power compensation, design an overall program of reactive power automatic compensation system to conquer various deficiencies of reactive power automatic compensation equipment.

  16. 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.

  17. The hormone prolactin is a novel, endogenous trophic factor able to regulate reactive glia and to limit retinal degeneration.

    PubMed

    Arnold, Edith; Thebault, Stéphanie; Baeza-Cruz, German; Arredondo Zamarripa, David; Adán, Norma; Quintanar-Stéphano, Andrés; Condés-Lara, Miguel; Rojas-Piloni, Gerardo; Binart, Nadine; Martínez de la Escalera, Gonzalo; Clapp, Carmen

    2014-01-29

    Retinal degeneration is characterized by the progressive destruction of retinal cells, causing the deterioration and eventual loss of vision. We explored whether the hormone prolactin provides trophic support to retinal cells, thus protecting the retina from degenerative pressure. Inducing hyperprolactinemia limited photoreceptor apoptosis, gliosis, and changes in neurotrophin expression, and it preserved the photoresponse in the phototoxicity model of retinal degeneration, in which continuous exposure of rats to bright light leads to retinal cell death and retinal dysfunction. In this model, the expression levels of prolactin receptors in the retina were upregulated. Moreover, retinas from prolactin receptor-deficient mice exhibited photoresponsive dysfunction and gliosis that correlated with decreased levels of retinal bFGF, GDNF, and BDNF. Collectively, these data unveiled prolactin as a retinal trophic factor that may regulate glial-neuronal cell interactions and is a potential therapeutic molecule against retinal degeneration. PMID:24478366

  18. Apoptosis Induction of Human Bladder Cancer Cells by Sanguinarine through Reactive Oxygen Species-Mediated Up-Regulation of Early Growth Response Gene-1

    PubMed Central

    Han, Min Ho; Park, Cheol; Jin, Cheng-Yun; Kim, Gi-Young; Chang, Young-Chae; Moon, Sung-Kwon; Kim, Wun-Jae; Choi, Yung Hyun

    2013-01-01

    Although the effects of sanguinarine, a benzophenanthridine alkaloid, on the inhibition of some kinds of cancer cell growth have been established, the underlying mechanisms are not completely understood. This study investigated possible mechanisms by which sanguinarine exerts its anticancer action in cultured human bladder cancer cell lines (T24, EJ, and 5637). Sanguinarine treatment resulted in concentration-response growth inhibition of the bladder cancer cells by inducing apoptosis. Sanguinarine-induced apoptosis was correlated with the up-regulation of Bax, the down-regulation of Bid and XIAP, the activation of caspases (-3, -8, and -9), and the generation of increased reactive oxygen species (ROS). The ROS scavenger N-acetyl cysteine (NAC) completely reversed the sanguinarine-triggered apoptotic events. In addition, sanguinarine effectively increased the activation of the c-Jun N-terminal kinase (JNK) and the expression of the early growth response gene-1 (Egr-1), which was recovered by pretreatment with NAC. Furthermore, knockdown of Egr-1 expression by small interfering RNA attenuated sanguinarine-induced apoptosis, but not the JNK inhibitor, indicating that the interception of ROS generation blocked the sanguinarine-induced apoptotic effects via deregulation of the expression of Egr-1 proteins. Taken together, the data provide evidence that sanguinarine is a potent anticancer agent, which inhibits the growth of bladder cancer cells and induces their apoptosis through the generation of free radicals. PMID:23717422

  19. 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. PMID:26825518

  20. Effects of radio frequency power on the chemical bonding, optical and mechanical properties for radio frequency reactive sputtered germanium carbide films

    NASA Astrophysics Data System (ADS)

    Hu, C. Q.; Xu, L.; Tian, H. W.; Jin, Z. S.; Lv, X. Y.; Zheng, W. T.

    2006-12-01

    Germanium carbide (Ge1-xCx) films have been prepared by radio frequency (RF) reactive sputtering of a pure Ge(111) target in a CH4/Ar mixture discharge, and their composition, chemical bonding, optical and mechanical properties have been investigated as a function of RF power. The relationship between the chemical bonding and the optical and mechanical properties of the Ge1-xCx films has been explored. The results show that the refractive index of Ge1-xCx films increases from 1.9 to 3.2 and the optical gap decreases from 1.9 to 1.0 eV as RF power increases from 80 to 250 W, which is due to an increase in the germanium content with increasing RF power. Also, it is found that the hardness of Ge1-xCx films increases with increasing RF power, which can be attributed to an increase in the fraction of sp3 Ge-C bonds at the expense of the sp2 C-C bonds in the Ge1-xCx films.

  1. 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

  2. Export of reactive nitrogen from coal-fired power plants in the U.S.: Estimates from a plume-in-grid modeling study - article no. D04308

    SciTech Connect

    Vijayaraghavan, K.; Zhang, Y.; Seigneur, C.; Karamchandani, P.; Snell, H.E.

    2009-02-15

    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 SO{sub 2} 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.

  3. 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.

  4. An Inductive Power and Data Telemetry Subsystem With Fast Transient Low Dropout Regulator for Biomedical Implants.

    PubMed

    Lin, Yu-Po; Tang, Kea-Tiong

    2016-04-01

    This paper presents a capacitorless low-dropout (LDO) regulator with fast transient response and data reverse telemetry circuit for fully implantable wireless transmission applications. We propose a novel hybrid feedback structure using high-frequency compensation technology to achieve a rapid transient response for the LDO regulator. To reduce the size of the implant and transmit neural recordings through the same coil without interfering with power transmission, the load-shift-key (LSK) modulation technique is adopted for back data telemetry. The proposed implantable chip, fabricated using commercial 0.18 μm complementary metal oxide semiconductor technology, yielded an output power of 15 mW. Under 1.15 V operation voltage, the maximum overshoot and undershoot voltages were less than 45 mV and 55 mV, respectively, for a 15 mA full-load current whose rising and falling time were less than 100 ns. The proposed LSK transceiver uses a digitized demodulator to improve bandwidth efficiency for low carrier frequency operation. PMID:26285218

  5. Thought suppression, impaired regulation of urges, and Addiction-Stroop predict affect-modulated cue-reactivity among alcohol dependent adults.

    PubMed

    Garland, Eric L; Carter, Kristin; Ropes, Katie; Howard, Matthew O

    2012-01-01

    Abstinent alcohol dependent individuals commonly employ thought suppression to cope with stress and intrusive cognitions about alcohol. This strategy may inadvertently bias attention towards alcohol-related stimuli while depleting neurocognitive resources needed to regulate urges, manifested as decreased heart rate variability (HRV) responsivity to alcohol cues. The present study tested the hypothesis that trait and state thought suppression, impaired regulation of urges, and alcohol attentional bias as measured by the Addiction-Stroop would have significant effects on the HRV responsivity of 58 adults in residential treatment for alcohol dependence (mean age=39.6 ± 9.4, 81% female) who participated in an affect-modulated cue-reactivity protocol. Regression analyses controlling for age, level of pre-treatment alcohol consumption, and baseline HRV indicated that higher levels of trait thought suppression, impaired regulation of alcohol urges, and attentional fixation on alcohol cues were associated with lower HRV responsivity during stress-primed alcohol cue-exposure. Moreover, there was a significant state × trait suppression interaction on HRV cue-responsivity, such that alcohol dependent persons reporting high levels of state and trait suppression exhibited less HRV during cue-exposure than persons reporting low levels of state and trait suppression. Results suggest that chronic thought suppression taxes regulatory resources reflected in reduced HRV responsivity, an effect that is particularly evident when high trait suppressors engage in intensive suppression of drinking-related thoughts under conditions of stress. Treatment approaches that offer effective alternatives to the maladaptive strategy of suppressing alcohol urges may be crucial for relapse prevention. PMID:21967855

  6. 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.

  7. Role of ARABIDOPSIS A-FIFTEEN in regulating leaf senescence involves response to reactive oxygen species and is dependent on ETHYLENE INSENSITIVE2

    PubMed Central

    Chen, Guan-Hong; Liu, Chia-Ping; Chen, Shu-Chen Grace; Wang, Long-Chi

    2012-01-01

    Leaf senescence is a highly regulated developmental process that is coordinated by several factors. Many senescence-associated genes (SAGs) have been identified, but their roles during senescence remain unclear. A sweet potato (Ipomoea batatas) SAG, named SPA15, whose function was unknown, was identified previously. To understand the role of SPA15 in leaf senescence further, the orthologue of SPA15 in Arabidopsis thaliana was identified and characterized, and it was named ARABIDOPSIS A-FIFTEEN (AAF). AAF was expressed in early senescent leaves and in tissues with highly proliferative activities. AAF was localized to the chloroplasts by transient expression in Arabidopsis mesophyll protoplasts. Overexpression of AAF (AAF-OX) in Arabidopsis promoted, but the T-DNA insertion mutant (aaf-KO), delayed age-dependent leaf senescence. Furthermore, stress-induced leaf senescence caused by continuous darkness was enhanced in AAF-OX but suppressed in aaf-KO. Transcriptome analysis of expression profiles revealed up-regulated genes related to pathogen defence, senescence, and oxidative stress in 3-week-old AAF-OX plants. Indeed, elevated levels of reactive oxygen species (ROS) and enhanced sensitivity to oxidative and dark stress were apparent in AAF-OX but reduced in aaf-KO. ETHYLENE INSENSITIVE2 (EIN2) was required for the dark- and ROS-induced senescence phenotypes in AAF-OX and the induction of AAF expression by treatment with the immediate precursor of ethylene, 1-aminocyclopropane-1-carboxylic acid. The results indicate the functional role of AAF is an involvement in redox homeostasis to regulate leaf senescence mediated by age and stress factors during Arabidopsis development. PMID:21940719

  8. Bcl-2 Regulates Reactive Oxygen Species Signaling and a Redox-Sensitive Mitochondrial Proton Leak in Mouse Pancreatic β-Cells.

    PubMed

    Aharoni-Simon, Michal; Shumiatcher, Rose; Yeung, Anthony; Shih, Alexis Z L; Dolinsky, Vernon W; Doucette, Christine A; Luciani, Dan S

    2016-06-01

    In pancreatic β-cells, controlling the levels of reactive oxygen species (ROS) is critical to counter oxidative stress, dysfunction and death under nutrient excess. Moreover, the fine-tuning of ROS and redox balance is important in the regulation of normal β-cell physiology. We recently demonstrated that Bcl-2 and Bcl-xL, in addition to promoting survival, suppress β-cell glucose metabolism and insulin secretion. Here, we tested the hypothesis that the nonapoptotic roles of endogenous Bcl-2 extend to the regulation of β-cell ROS and redox balance. We exposed mouse islet cells and MIN6 cells to the Bcl-2/Bcl-xL antagonist Compound 6 and the Bcl-2-specific antagonist ABT-199 and evaluated ROS levels, Ca(2+) responses, respiratory control, superoxide dismutase activity and cell death. Both acute glucose stimulation and the inhibition of endogenous Bcl-2 progressively increased peroxides and stimulated superoxide dismutase activity in mouse islets. Importantly, conditional β-cell knockout of Bcl-2 amplified glucose-induced formation of peroxides. Bcl-2 antagonism also induced a mitochondrial proton leak that was prevented by the antioxidant N-acetyl-L-cysteine and, therefore, secondary to redox changes. We further established that the proton leak was independent of uncoupling protein 2 but partly mediated by the mitochondrial permeability transition pore. Acutely, inhibitor-induced peroxides promoted Ca(2+) influx, whereas under prolonged Bcl inhibition, the elevated ROS was required for induction of β-cell apoptosis. In conclusion, our data reveal that endogenous Bcl-2 modulates moment-to-moment ROS signaling and suppresses a redox-regulated mitochondrial proton leak in β-cells. These noncanonical roles of Bcl-2 may be important for β-cell function and survival under conditions of high metabolic demand. PMID:27070098

  9. 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

  10. The Shedding of CD62L (L-Selectin) Regulates the Acquisition of Lytic Activity in Human Tumor Reactive T Lymphocytes

    PubMed Central

    Yang, Shicheng; Liu, Fang; Wang, Qiong J.; Rosenberg, Steven A.; Morgan, Richard A.

    2011-01-01

    CD62L/L-selectin is a marker found on naïve T cells and further distinguishes central memory (Tcm, CD62L+) from effector memory (Tem, CD62L−) T cells. The regulation of CD62L plays a pivotal role in controlling the traffic of T lymphocytes to and from peripheral lymph nodes. CD62L is shed from the cell membrane following T cell activation, however, the physiological significance of this event remains to be elucidated. In this study, we utilized in vitro generated anti-tumor antigen T cells and melanoma lines as a model to evaluate the dynamics of CD62L shedding and expression of CD107a as a marker of lytic activity. Upon encounter, with matched tumor lines, antigen reactive T cells rapidly lose CD62L expression and this was associated with the acquisition of CD107a. By CD62L ELISA, we confirmed that this transition was mediated by the shedding of CD62L when T cells encountered specific tumor antigen. The introduction of a shedding resistant mutant of CD62L into the tumor antigen-reactive T cell line JKF6 impaired CD107a acquisition following antigen recognition and this was correlated with decreased lytic activity as measured by 51Cr release assays. The linkage of the shedding of CD62L from the surface of anti-tumor T cells and acquisition of lytic activity, suggests a new function for CD62L in T cell effector functions and anti-tumor activity. PMID:21829468

  11. Distinct p21 requirements for regulating normal and self-reactive T cells through IFN-γ production

    PubMed Central

    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

    2015-01-01

    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. PMID:25573673

  12. 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

  13. MPP Regulated Bus Power System Management for LEO and GEO Missions

    NASA Astrophysics Data System (ADS)

    Capel, Antoine; Giral, Roberto

    2008-09-01

    An emerging solar array management, called MPPC (Maximum Power Point Controller) is described, which consists in the identification of the Tada and Carter electrical characteristics i(v) of a solar array. The computation of the 3 parameters iSC, iR , and AkT/q of the electrical characteristics conducts to solve a 3 unknown 3 equation system using 3 operating point measurements. The MPP computation is made by a microprocessor which solves the equation dP/dv=0. The voltage coordinate of the MPP becomes the reference voltage of the off the shelf regulator which regulates the solar array voltage. Associated with an S3R, the acquisition of the MPP is immediate as the parameter iSC, is always available and the dark current iR is not affected. The Envisat application has been used for the comparison of this principle, in a new PSS topology called MPPC Regulated bus against 3 existing topologies, mostly used for spacecrafts. It comes that the MPPC allows to utilise the full solar array capabilities and improves by 18% the performances.

  14. Fear extinction and acute stress reactivity reveal a role of LPA(1) receptor in regulating emotional-like behaviors.

    PubMed

    Pedraza, C; Sánchez-López, J; Castilla-Ortega, E; Rosell-Valle, C; Zambrana-Infantes, E; García-Fernández, M; Rodriguez de Fonseca, F; Chun, J; Santín, L J; Estivill-Torrús, G

    2014-09-01

    LPA1 receptor is one of the six characterized G protein-coupled receptors (LPA1-6) through which lysophosphatidic acid acts as an intercellular signaling molecule. It has been proposed that this receptor has a role in controlling anxiety-like behaviors and in the detrimental consequences of stress. Here, we sought to establish the involvement of the LPA1 receptor in emotional regulation. To this end, we examined fear extinction in LPA1-null mice, wild-type and LPA1 antagonist-treated animals. In LPA1-null mice we also characterized the morphology and GABAergic properties of the amygdala and the medial prefrontal cortex. Furthermore, the expression of c-Fos protein in the amygdala and the medial prefrontal cortex, and the corticosterone response following acute stress were examined in both genotypes. Our data indicated that the absence of the LPA1 receptor significantly inhibited fear extinction. Treatment of wild-type mice with the LPA1 antagonist Ki16425 mimicked the behavioral phenotype of LPA1-null mice, revealing that the LPA1 receptor was involved in extinction. Immunohistochemistry studies revealed a reduction in the number of neurons, GABA+ cells, calcium-binding proteins and the volume of the amygdala in LPA1-null mice. Following acute stress, LPA1-null mice showed increased corticosterone and c-Fos expression in the amygdala. In conclusion, LPA1 receptor is involved in emotional behaviors and in the anatomical integrity of the corticolimbic circuit, the deregulation of which may be a susceptibility factor for anxiety disorders and a potential therapeutic target for the treatment of these diseases. PMID:23775489

  15. A Method for Capturing Sub-Gridscale Interactions in Numerical Simulation of Flow and Reactive Transport in Power-Law Media

    NASA Astrophysics Data System (ADS)

    Travis, B. J.

    2013-12-01

    For nonlinear, coupled flow and reactive transport in heterogeneous systems, capturing sub-gridscale dynamics is a serious challenge for coarse-grained numerical simulation. Even simply for linear, uncomplicated flow systems, accurate estimation of sub-gridscale effects may require averaging over a possibly tensor, multi-scale permeability distribution. Stochastic process modeling and statistical analysis methods are available and are being improved for calculating average and variance properties of flow and transport systems. Frequently, in addition to the average dynamics, a solution for an individual realization, or for many realizations, is desired or required. For media whose smaller-scale heterogeneity can be approximated by a power law (fractal) model (and this is approximately true for many soils), fractal interpolating functions, constrained by measured properties and distributions, provide an efficient way to capture sub-gridscale dynamics for individual realizations. An advantage of this approach is that it can be incorporated readily into conventional finite difference or finite element flow and transport codes, providing a multi-resolution solution for less cost than a finely-grained one. Several examples illustrate the potential usefulness of this approach for numerical simulation of flow and reactive transport in heterogeneous media. Comparisons are made to finely gridded traditional numerical solutions. Limitations and conditions of use are discussed.

  16. On the Use of Energy Storage Technologies for Regulation Services in Electric Power Systems with Significant Penetration of Wind Energy

    SciTech Connect

    Yang, Bo; Makarov, Yuri V.; DeSteese, John G.; Vishwanathan, Vilanyur V.; Nyeng, Preben; McManus, Bart; Pease, John

    2008-05-27

    Energy produced by intermittent renewable resources is sharply increasing in the United States. At high penetration levels, volatility of wind power production could cause additional problems for the power system balancing functions such as regulation. This paper reports some partial results of a project work, recently conducted by the Pacific Northwest National Laboratory (PNNL) for Bonneville Power Administration (BPA). The project proposes to mitigate additional intermittency with the help of Wide Area Energy Management System (WAEMS) that would provide a two-way simultaneous regulation service for the BPA and California ISO systems by using a large energy storage facility. The paper evaluates several utility-scale energy storage technology options for their usage as regulation resources. The regulation service requires a participating resource to quickly vary its power output following the rapidly and frequently changing regulation signal. Several energy storage options have been analyzed based on thirteen selection criteria. The evaluation process resulted in the selection of flywheels, pumped hydro electric power (or conventional hydro electric power) plant and sodium sulfur or nickel cadmium batteries as candidate technologies for the WAEMS project. A cost benefit analysis should be conducted to narrow the choice to one technology.

  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. Arabidopsis OST1 protein kinase mediates the regulation of stomatal aperture by abscisic acid and acts upstream of reactive oxygen species production.

    PubMed

    Mustilli, Anna-Chiara; Merlot, Sylvain; Vavasseur, Alain; Fenzi, Francesca; Giraudat, Jérôme

    2002-12-01

    During drought, the plant hormone abscisic acid (ABA) triggers stomatal closure, thus reducing water loss. Using infrared thermography, we isolated two allelic Arabidopsis mutants (ost1-1 and ost1-2) impaired in the ability to limit their transpiration upon drought. These recessive ost1 mutations disrupted ABA induction of stomatal closure as well as ABA inhibition of light-induced stomatal opening. By contrast, the ost1 mutations did not affect stomatal regulation by light or CO(2), suggesting that OST1 is involved specifically in ABA signaling. The OST1 gene was isolated by positional cloning and was found to be expressed in stomatal guard cells and vascular tissue. In-gel assays indicated that OST1 is an ABA-activated protein kinase related to the Vicia faba ABA-activated protein kinase (AAPK). Reactive oxygen species (ROS) were shown recently to be an essential intermediate in guard cell ABA signaling. ABA-induced ROS production was disrupted in ost1 guard cells, whereas applied H(2)O(2) or calcium elicited the same degree of stomatal closure in ost1 as in the wild type. These results suggest that OST1 acts in the interval between ABA perception and ROS production. The relative positions of ost1 and the other ABA-insensitive mutations in the ABA signaling network (abi1-1, abi2-1, and gca2) are discussed. PMID:12468729

  19. Improved nuclear power plant operations and safety through performance-based safety regulation.

    PubMed

    Golay, M W

    2000-01-01

    This paper illustrates some of the promise and needed future work for risk-informed, performance-based regulation (RIPBR). RIPBR is an evolving alternative to the current prescriptive method of nuclear safety regulation. Prescriptive regulation effectively constitutes a long, fragmented checklist of requirements that safety-related systems in a plant must satisfy. RIPBR, instead, concentrates upon satisfying negotiated performance goals and incentives for judging and rewarding licensee behavior to improve safety and reduce costs. In a project reported here, a case study was conducted concerning a pressurized water reactor (PWR) emergency diesel generator (EDG). Overall, this work has shown that the methods of RIPBR are feasible to use, and capable of justifying simultaneous safety and economic nuclear power improvements. However, it also reveals several areas where the framework of RIPBR should be strengthened. First, researchers need better data and understanding regarding individual component-failure modes that may cause components to fail. Not only are more data needed on failure rates, but more data and understanding are needed to enable analysts to evaluate whether these failures become more likely as the interval between tests is increased. This is because the current state of failure data is not sufficiently finely detailed to define the failure rates of individual component failure modes; such knowledge is needed when changing component-specific regulatory requirements. Second, the role of component testing, given that a component has failed, needs to be strengthened within the context of RIPBR. This includes formulating requirements for updating the prior probability distribution of a component failure rate and conducting additional or more frequent testing. Finally, as a means of compensating for unavoidable uncertainty as an obstacle to regulatory decision-making, limits to knowledge must be treated explicitly and formally. This treatment includes the

  20. 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.

  1. 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.

  2. Coordination power adjustment of surface-regulating polymers for shaping gold polyhedral nanocrystals.

    PubMed

    Lee, Seon Joo; Park, Garam; Seo, Daeha; Ka, Duyoun; Kim, Sang Youl; Chung, Im Sik; Song, Hyunjoon

    2011-07-18

    PVP (poly(vinyl pyrrolidone)) is a common polymer that behaves as a surface-regulating agent that shapes metal nanocrystals in the polyol process. We have used different polymers containing tertiary amide groups, namely PVCL (poly(vinyl caprolactam)) and PDMAm (poly(N,N-dimethyl acrylamide)), for the synthesis of gold polyhedrons, including octahedrons, cuboctahedrons, cubes, and higher polygons, under the present polyol reaction conditions. The basicity and surface coordination power of the polymers are in the order of PVCL, PVP, and PDMAm. A correlation is observed between the coordination power of the polymers and the resulting gold nanocrystal size. Strong coordination and electron donation from the polymer functional groups to the gold surface restrict particle growth rates, which leads to small nanocrystals. The use of PVCL can yield gold polyhedral structures with small sizes, which cannot be achieved in the reactions with PVP. Simultaneous hydrolysis of the amide group in PDMAm leads to carboxylate functionality, which is very useful for generating chemical and bioconjugates through the formation of ester and amide bonds. PMID:21656861

  3. 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.

  4. Reactive arthritis

    MedlinePlus

    Reactive arthritis is a group of conditions that may involve the joints, eyes, and urinary and genital systems. ... The exact cause of reactive arthritis is unknown. It occurs most often in men younger than age 40. It may follow an infection in the urethra ...

  5. Role of the yeast acetyltransferase Mpr1 in oxidative stress: regulation of oxygen reactive species caused by a toxic proline catabolism intermediate.

    PubMed

    Nomura, Michiyo; Takagi, Hiroshi

    2004-08-24

    The MPR1 gene, which is found in the Sigma1278b strain but is not present in the sequenced laboratory strain S288C, of the budding yeast Saccharomyces cerevisiae encodes a previously uncharacterized N-acetyltransferase that detoxifies the proline analogue azetidine-2-carboxylate (AZC). However, it is unlikely that AZC is a natural substrate of Mpr1 because AZC is found only in some plant species. In our search for the physiological function of Mpr1, we found that mpr1-disrupted cells were hypersensitive to oxidative stresses and contained increased levels of reactive oxygen species (ROS). In contrast, overexpression of MPR1 leads to an increase in cell viability and a decrease in ROS level after oxidative treatments. These results indicate that Mpr1 can reduce intracellular oxidation levels. Because put2-disrupted yeast cells lacking Delta(1)-pyrroline-5-carboxylate (P5C) dehydrogenase have increased ROS, we examined the role of Mpr1 in put2-disrupted strains. When grown on media containing urea and proline as the nitrogen source, put2-disrupted cells did not grow as well as WT cells and accumulated intracellular levels of P5C that were first detected in yeast cells and ROS. On the other hand, put2-disrupted cells that overexpressed MPR1 had considerably lower ROS levels. In vitro studies with bacterially expressed Mpr1 demonstrated that Mpr1 can acetylate P5C, or, more likely, its equilibrium compound glutamate-gamma-semialdehyde, at neutral pH. These results suggest that the proline catabolism intermediate P5C is toxic to yeast cells because of the formation of ROS, and Mpr1 regulates the ROS level under P5C-induced oxidative stress. PMID:15308773

  6. Honokiol induces autophagic cell death in malignant glioma through reactive oxygen species-mediated regulation of the p53/PI3K/Akt/mTOR signaling pathway.

    PubMed

    Lin, Chien-Ju; Chen, Ta-Liang; Tseng, Yuan-Yun; Wu, Gong-Jhe; Hsieh, Ming-Hui; Lin, Yung-Wei; Chen, Ruei-Ming

    2016-08-01

    Honokiol, an active constituent extracted from the bark of Magnolia officinalis, possesses anticancer effects. Apoptosis is classified as type I programmed cell death, while autophagy is type II programmed cell death. We previously proved that honokiol induces cell cycle arrest and apoptosis of U87 MG glioma cells. Subsequently in this study, we evaluated the effect of honokiol on autophagy of glioma cells and examined the molecular mechanisms. Administration of honokiol to mice with an intracranial glioma increased expressions of cleaved caspase 3 and light chain 3 (LC3)-II. Exposure of U87 MG cells to honokiol also induced autophagy in concentration- and time-dependent manners. Results from the addition of 3-methyladenine, an autophagy inhibitor, and rapamycin, an autophagy inducer confirmed that honokiol-induced autophagy contributed to cell death. Honokiol decreased protein levels of PI3K, phosphorylated (p)-Akt, and p-mammalian target of rapamycin (mTOR) in vitro and in vivo. Pretreatment with a p53 inhibitor or transfection with p53 small interfering (si)RNA suppressed honokiol-induced autophagy by reversing downregulation of p-Akt and p-mTOR expressions. In addition, honokiol caused generation of reactive oxygen species (ROS), which was suppressed by the antioxidant, vitamin C. Vitamin C also inhibited honokiol-induced autophagic and apoptotic cell death. Concurrently, honokiol-induced alterations in levels of p-p53, p53, p-Akt, and p-mTOR were attenuated following vitamin C administration. Taken together, our data indicated that honokiol induced ROS-mediated autophagic cell death through regulating the p53/PI3K/Akt/mTOR signaling pathway. PMID:27236003

  7. State-dependent chemical reactivity of an engineered cysteine reveals conformational changes in the outer vestibule of the cystic fibrosis transmembrane conductance regulator.

    PubMed

    Zhang, Zhi-Ren; Song, Binlin; McCarty, Nael A

    2005-12-23

    Cystic fibrosis transmembrane conductance regulator (CFTR) chloride channels are gated by binding and hydrolysis of ATP at the nucleotide-binding domains (NBDs). We used covalent modification of CFTR channels bearing a cysteine engineered at position 334 to investigate changes in pore conformation that might accompany channel gating. In single R334C-CFTR channels studied in excised patches, modification by [2-(trimethylammonium)ethyl] methanethiosulfonate (MTSET+), which increases conductance, occurred only during channel closed states. This suggests that the rate of reaction of the cysteine was greater in closed channels than in open channels. R334C-CFTR channels in outside-out macropatches activated by ATP alone were modified with first order kinetics upon rapid exposure to MTSET+. Modification was much slower when channels were locked open by the addition of nonhydrolyzable nucleotide or when the R334C mutation was coupled to a second mutation, K1250A, which greatly decreases channel closing rate. In contrast, modification was faster in R334C/K464A-CFTR channels, which exhibit prolonged interburst closed states. These data indicate that the reactivity of the engineered cysteine in R334C-CFTR is state-dependent, providing evidence of changes in pore conformation coupled to ATP binding and hydrolysis at the NBDs. The data also show that maneuvers that lock open R334C-CFTR do so by locking channels into the prominent s2 subconductance state, suggesting that the most stable conducting state of the pore reflects the fully occupied, prehydrolytic state of the NBDs. PMID:16227620

  8. IL-1β and reactive oxygen species differentially regulate neutrophil directional migration and Basal random motility in a zebrafish injury-induced inflammation model.

    PubMed

    Yan, Bo; Han, Peidong; Pan, Lifeng; Lu, Wei; Xiong, Jingwei; Zhang, Mingjie; Zhang, Wenqing; Li, Li; Wen, Zilong

    2014-06-15

    During inflammation, the proper inflammatory infiltration of neutrophils is crucial for the host to fight against infections and remove damaged cells and detrimental substances. IL-1β and NADPH oxidase-mediated reactive oxygen species (ROS) have been implicated to play important roles in this process. However, the cellular and molecular basis underlying the actions of IL-1β and ROS and their relationship during inflammatory response remains undefined. In this study, we use the zebrafish model to investigate these issues. We find that, similar to that of NADPH oxidase-mediated ROS signaling, the Il-1β-Myd88 pathway is required for the recruitment of neutrophils, but not macrophages, to the injury-induced inflammatory site, whereas it is dispensable for bacterial-induced inflammation. Interestingly, the Il-1β-Myd88 pathway is independent of NADPH oxidase-mediated ROS signaling and critical for the directional migration, but not the basal random movement, of neutrophils. In contrast, the NADPH oxidase-mediated ROS signaling is required for both basal random movement and directional migration of neutrophils. We further document that ectopic expression of Il-1β in zebrafish induces an inflammatory disorder, which can be suppressed by anti-inflammatory treatment. Our findings reveal that the Il-1β-Myd88 axis and NADPH oxidase-mediated ROS signaling are two independent pathways that differentially regulate neutrophil migration during sterile inflammation. In addition, Il-1β overexpressing Tg(hsp70:(m)il-1β_eGFP;lyz:DsRed2)hkz10t;nz50 transgenic zebrafish provides a useful animal model for the study of chronic inflammatory disorder and for anti-inflammatory drug discovery. PMID:24835391

  9. 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.

  10. Down-Regulation of Porcine Heart Diaphorase Reactivity by Trimanganese Hexakis(3,5-Diisopropylsalicylate), Mn(3)(3,5-DIPS)6, and Down-Regulation of Nitric Oxide Synthase Reactivity by Mn(3)(3,5-DIPS)(6) and Cu(II)(2)(3,5-DIPS)(4).

    PubMed

    Booth, B L; Pitters, E; Mayer, B; Sorenson, J R

    1999-01-01

    Purposes of this work were to examine the plausible down-regulation of porcine heart diaphorase (PHD) enzyme reactivity and nitric oxide synthase (NOS) enzyme reactivity by trimanganese hexakis(3,5-diisopropylsalicylate), [Mn(3)(3,5-DIPS)(6)] as well as dicopper tetrakis(3,5- diisopropylsalicylate, [Cu(II)(2)(3,5-DIPS)(4)] as a mechanistic accounting for their pharmacological activities.Porcine heart disease was found to oxidize 114 muM reduced nicotinamide-adenine- dinucleotide-'(3)-phosphate (NADPH) with a corresponding reduction of an equivalent concentration of 2,6-dichlorophenolindophenol (DCPIP). As reported for Cu(II)(2) (3,5-DIPS)(4), addition of Mn(3)(3,5-DIPS)(6) to this reaction mixture decreased the reduction of DCPIP without significantly affecting the oxidation of NADPH. The concentration of Mn(3)(3,5-DIPS)(6) that produced a 50% decrease in DCPIP reduction (IC(50)) was found to be 5muM. Mechanistically, this inhibition of DCPIP reduction with ongoing NADPH oxidation by PHD was found to be due to the ability of Mn(3)(3,5-DIPS)(6) to serve as a catalytic electron acceptor for reduced PHD as had been reported for Cu(II)(2)(3,5-DIPS)(4). This catalytic decrease in reduction of DCPIP by Mn(3)(3,5-DIPS)(6) was enhanced by the presence of a large concentration of DCPIP and decreased by the presence of a large concentration of NADPH, consistent with what had been observed for the activity of Cu(II)(2)(3,5-DIPS)(4)Oxidation of NADPH by PHD in the presence of Mn(3)(3,5-DIPS)(6) and the absence of DCPIP was linearly related to the concentration of added Mn(3)(3,5-DIPS)(6) through the concentration range of 2.4 muM to 38muM with a 50% recovery of NADPH oxidation by PHD at a concentration of 6 muM Mn(3)(3,5-DIPS)(6)Conversion of [(3)H] L-Arginine to [(3)H] L-Citrulline by purified rat brain nitric oxide synthase (NOS) was decreased in a concentrated related fashion with the addition of Mn(3)(3,5-DIPS)(6) as well as Cu(II)(2)(3,5-DIPS)(4) which is an extention of

  11. The effect on thermal power plant design due to the implementation of China`s new environmental laws and regulations

    SciTech Connect

    Zheng Dingrong; Liu Yongjiu; Lei Kechang

    1996-10-01

    In light of the requirements of China`s new environmental protection laws and regulations, the countermeasures adopted by the Chinese government to protect environment, and China`s Ninth Five-Year Plan (1996--2000) and Long-Term Target for the Year 2010, this paper describes the considerations and countermeasures that shall be taken in power plant construction and design.

  12. 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.

  13. 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.

  14. 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.

  15. Reactive Arthritis

    MedlinePlus

    ... with treatment and may cause joint damage. What Research Is Being Conducted on Reactive Arthritis? Researchers continue ... such as methotrexate and sulfasalazine. More information on research is available from the following websites: National Institutes ...

  16. Preparation of diamond-like carbon films using reactive Ar/CH4 high power impulse magnetron sputtering system with negative pulse voltage source for substrate

    NASA Astrophysics Data System (ADS)

    Kimura, Takashi; Kamata, Hikaru

    2016-04-01

    Diamond-like carbon films were prepared using a reactive Ar/CH4 high-power impulse magnetron sputtering system with a negative pulse voltage source for the substrate, changing the CH4 fraction up to 15% in the total pressure range from 0.3 to 2 Pa. The magnitude of the negative pulse voltage for the substrate was also varied up to about 500 V. The hardness of films monotonically increased with increasing magnitude of the negative pulse voltage. The films with hardnesses between 16.5 and 23 GPa were prepared at total pressures less than 0.5 Pa and CH4 fractions less than 10% by applying an appropriate negative pulse voltage of 300-400 V. In X-ray photoelectron spectroscopy, the area ratio C-C sp3/(C-C sp2 + C-C sp3) in the C 1s core level was higher than 30% at pressures less than 0.5 Pa and CH4 fractions less than 15%. On the other hand, the films with hardnesses between 5 and 10 GPa were prepared with a relatively high growth rate at the partial pressures of CH4 higher than 0.1 Pa. However, the observation of the photoluminescence background in Raman spectroscopy indicated a relatively high hydrogen content.

  17. 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.

  18. Regulation of pyruvate dehydrogenase activity and citric acid cycle intermediates during high cardiac power generation

    PubMed Central

    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

    2005-01-01

    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 14C-glucose and 3H-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. PMID:15550462

  19. 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.

  20. 47 CFR 74.780 - Broadcast regulations applicable to translators, low power, and booster stations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.780 Broadcast... TV translator, low power TV, and TV booster stations: Section 73.653—Operation of TV aural and visual... non-network program arrangements. Part 73, Subpart G—Emergency Broadcast System (for low power...

  1. 47 CFR 74.780 - Broadcast regulations applicable to translators, low power, and booster stations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.780 Broadcast... TV translator, low power TV, and TV booster stations: Section 73.653—Operation of TV aural and visual... non-network program arrangements. Part 73, Subpart G—Emergency Broadcast System (for low power...

  2. 47 CFR 74.780 - Broadcast regulations applicable to translators, low power, and booster stations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.780 Broadcast... TV translator, low power TV, and TV booster stations: Section 73.653—Operation of TV aural and visual... non-network program arrangements. Part 73, Subpart G—Emergency Broadcast System (for low power...

  3. Hybrid Stochastic Search Technique based Suboptimal AGC Regulator Design for Power System using Constrained Feedback Control Strategy

    NASA Astrophysics Data System (ADS)

    Ibraheem, Omveer, Hasan, N.

    2010-10-01

    A new hybrid stochastic search technique is proposed to design of suboptimal AGC regulator for a two area interconnected non reheat thermal power system incorporating DC link in parallel with AC tie-line. In this technique, we are proposing the hybrid form of Genetic Algorithm (GA) and simulated annealing (SA) based regulator. GASA has been successfully applied to constrained feedback control problems where other PI based techniques have often failed. The main idea in this scheme is to seek a feasible PI based suboptimal solution at each sampling time. The feasible solution decreases the cost function rather than minimizing the cost function.

  4. Reactive arthritis.

    PubMed

    Keat, A

    1999-01-01

    Reactive arthritis is one of the spondyloarthropathy family of clinical syndromes. The clinical features are those shared by other members of the spondyloarthritis family, though it is distinguished by a clear relationship with a precipitating infection. Susceptibility to reactive arthritis is closely linked with the class 1 HLA allele B27; it is likely that all sub-types pre-dispose to this condition. The link between HLA B27 and infection is mirrored by the development of arthritis in HLA B27-transgenic rats. In this model, arthritis does not develop in animals maintained in a germ-free environment. Infections of the gastrointestinal, genitourinary and respiratory tract appear to provoke reactive arthritis and a wide range of pathogens has now been implicated. Although mechanistic parallels may exist, reactive arthritis is distinguished from Lyme disease, rheumatic fever and Whipple's disease by virtue of the distinct clinical features and the link with HLA B27. As in these conditions both antigens and DNA of several micro-organisms have been detected in joint material from patients with reactive arthritis. The role of such disseminated microbial elements in the provocation or maintenance of arthritis remains unclear. HLA B27-restricted T-cell responses to microbial antigens have been demonstrated and these may be important in disease pathogenesis. The importance of dissemination of bacteria from sites of mucosal infection and their deposition in joints has yet to be fully understood. The role of antibiotic therapy in the treatment of reactive arthritis is being explored; in some circumstances, both the anti-inflammatory and anti-microbial effects of certain antibiotics appear to be valuable. The term reactive arthritis should be seen as a transitory one, reflecting a concept which may itself be on the verge of replacement, as our understanding of the condition develops. Nevertheless it appropriately describes arthritis that is associated with demonstrable

  5. Reactive sputtering of δ-ZrH{sub 2} thin films by high power impulse magnetron sputtering and direct current magnetron sputtering

    SciTech Connect

    Högberg, Hans Tengdelius, Lina; Eriksson, Fredrik; Broitman, Esteban; Lu, Jun; Jensen, Jens; Hultman, Lars; Samuelsson, Mattias

    2014-07-01

    Reactive sputtering by high power impulse magnetron sputtering (HiPIMS) and direct current magnetron sputtering (DCMS) of a Zr target in Ar/H{sub 2} plasmas was employed to deposit Zr-H films on Si(100) substrates, and with H content up to 61 at. % and O contents typically below 0.2 at. % as determined by elastic recoil detection analysis. X-ray photoelectron spectroscopy reveals a chemical shift of ∼0.7 eV to higher binding energies for the Zr-H films compared to pure Zr films, consistent with a charge transfer from Zr to H in a zirconium hydride. X-ray diffraction shows that the films are single-phase δ-ZrH{sub 2} (CaF{sub 2} type structure) at H content >∼55 at. % and pole figure measurements give a 111 preferred orientation for these films. Scanning electron microscopy cross-section images show a glasslike microstructure for the HiPIMS films, while the DCMS films are columnar. Nanoindentation yield hardness values of 5.5–7 GPa for the δ-ZrH{sub 2} films that is slightly harder than the ∼5 GPa determined for Zr films and with coefficients of friction in the range of 0.12–0.18 to compare with the range of 0.4–0.6 obtained for Zr films. Wear resistance testing show that phase-pure δ-ZrH{sub 2} films deposited by HiPIMS exhibit up to 50 times lower wear rate compared to those containing a secondary Zr phase. Four-point probe measurements give resistivity values in the range of ∼100–120 μΩ cm for the δ-ZrH{sub 2} films, which is slightly higher compared to Zr films with values in the range 70–80 μΩ cm.

  6. Genomic Analysis of Reactive Astrogliosis

    PubMed Central

    Zamanian, JL; Xu, L; Foo, LC; Nouri, N; Zhou, L; Giffard, RG; Barres, BA

    2012-01-01

    Reactive astrogliosis is characterized by a profound change in astrocyte phenotype in response to all CNS injuries and diseases. To better understand the reactive astrocyte state, we used Affymetrix GeneChip arrays to profile gene expression in populations of reactive astrocytes isolated at various time points after induction using two mouse injury models, ischemic stroke and neuroinflammation. We find reactive gliosis consists of a rapid, but quickly attenuated induction of gene expression after insult and identify two induced genes, Lcn2 and Serpina3n, as strong markers of reactive astrocytes. Strikingly, reactive astrocyte phenotype strongly depended on the type of inducing injury. Although there is a core set of genes that is up-regulated in reactive astrocytes from both injury models, at least 50% of the altered gene expression is specific to a given injury type. Reactive astrocytes in ischemia exhibited a molecular phenotype that suggests that they may be beneficial or protective, whereas reactive astrocytes induced by LPS exhibited a phenotype that suggests that they may be detrimental. These findings demonstrate that, despite well established commonalities, astrocyte reactive gliosis is a highly heterogeneous state in which astrocyte activities are altered to respond to the specific injury. This raises the question of how many subtypes of reactive astrocytes exist. Our findings provide transcriptome databases for two subtypes of reactive astrocytes that will be highly useful in generating new and testable hypotheses of their function, as well as for providing new markers to detect different types of reactive astrocytes in human neurological diseases. PMID:22553043

  7. 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.

  8. "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…

  9. 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

    ... power ratings of multichannel home theater amplifiers. 65 FR 80798 (Dec. 22, 2000). The SNPR elicited... testing multichannel amplifiers . 67 FR 1915 (Jan. 15, 2002). Although CEA subsequently issued a standard... industry had not agreed on a power rating standard for multichannel amplifiers. 72 FR 13052 (March 20,...

  10. 47 CFR 74.780 - Broadcast regulations applicable to translators, low power, and booster stations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.780 Broadcast... TV translator, low power TV, and TV booster stations: Part 5—Experimental authorizations. Section 73.653—Operation of TV aural and visual transmitters. Section 73.658—Affiliation agreements and...

  11. 47 CFR 74.780 - Broadcast regulations applicable to translators, low power, and booster stations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.780 Broadcast... TV translator, low power TV, and TV booster stations: Part 5—Experimental authorizations. Section 73.653—Operation of TV aural and visual transmitters. Section 73.658—Affiliation agreements and...

  12. 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

  13. 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.

  14. 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

  15. Development of ultra high power, valve-regulated lead-acid batteries for industrial applications

    NASA Astrophysics Data System (ADS)

    Soria, M. Luisa; Valenciano, Jesús; Ojeda, Araceli

    There is a recent market trend towards industrial battery powered products that demand occasionally very high discharge rates. This fact is today solved by oversizing the battery or by using more expensive high power nickel-cadmium batteries. Within an EC funded project, ultra high power lead-acid batteries for UPS applications are being developed. The batteries are characterised by a thin electrode design linked to the use of novel separator materials to increase the battery life under floating and deep cycling conditions. Battery performance under different working conditions is presented, in comparison to standard products, and the battery improvements and failure mechanisms are also discussed.

  16. Impact of Cognitive-Behavioral Therapy for Social Anxiety Disorder on the Neural Bases of Emotional Reactivity to and Regulation of Social Evaluation

    PubMed Central

    Goldin, Philippe R.; Ziv, Michal; Jazaieri, Hooria; Weeks, Justin; Heimberg, Richard G.; Gross, James J.

    2014-01-01

    We examined whether Cognitive-Behavioral Therapy (CBT) for social anxiety disorder (SAD) would modify self-reported negative emotion and functional magnetic resonance imaging brain responses when reacting to and reappraising social evaluation, and tested whether changes would predict treatment outcome in 59 patients with SAD who completed CBT or waitlist groups. For reactivity, compared to waitlist, CBT resulted in (a) increased brain responses in right superior frontal gyrus (SFG), inferior parietal lobule (IPL), and middle occipital gyrus (MOG) when reacting to social praise, and (b) increases in right SFG and IPL and decreases in left posterior superior temporal gyrus (pSTG) when reacting to social criticism. For reappraisal, compared to waitlist, CBT resulted in greater (c) reductions in self-reported negative emotion, and (d) increases in brain responses in right SFG and MOG, and decreases in left pSTG. A linear regression found that after controlling for CBT-induced changes in reactivity and reappraisal negative emotion ratings and brain changes in reactivity to praise and criticism, reappraisal of criticism brain response changes predicted 24% of the unique variance in CBT-related reductions in social anxiety. Thus, one mechanism underlying CBT for SAD may be changes in reappraisal-related brain responses to social criticism. PMID:25193002

  17. 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.

  18. 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

  19. Fuel Temperature Coefficient of Reactivity

    SciTech Connect

    Loewe, W.E.

    2001-07-31

    A method for measuring the fuel temperature coefficient of reactivity in a heterogeneous nuclear reactor is presented. The method, which is used during normal operation, requires that calibrated control rods be oscillated in a special way at a high reactor power level. The value of the fuel temperature coefficient of reactivity is found from the measured flux responses to these oscillations. Application of the method in a Savannah River reactor charged with natural uranium is discussed.

  20. 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.

  1. 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 ...

  2. 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…

  3. 76 FR 11177 - Frequency Regulation Compensation in the Organized Wholesale Power Markets

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-01

    ... Utilities; Recovery of Stranded Costs by Public Utilities and Transmitting Utilities, Order No. 888, 61 FR... FR 12274 (Mar. 14, 1997), FERC Stats. & Regs. ] 31,048, order on reh'g, Order No. 888-B, 81 FERC ] 61... discrimination by requiring a uniform price for regulation capacity paid to all cleared resources and...

  4. 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…

  5. 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

    NASA Astrophysics Data System (ADS)

    Zizin, M. N.; Zimin, V. G.; Zizina, S. N.; Kryakvin, L. V.; Pitilimov, V. A.; Tereshonok, V. A.

    2010-12-01

    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.

  6. 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.

  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. Regulating glottal airflow in phonation: application of the maximum power transfer theorem to a low dimensional phonation model.

    PubMed

    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. PMID:11831809

  9. 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.

  10. 76 FR 67259 - Frequency Regulation Compensation in the Organized Wholesale Power Markets

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-31

    ... Markets, 76 FR 11,177, 134 FERC ] 61,124 (2011) (NOPR). \\18\\ See Appendix for a list of commenters. II... up 100 percent of the NO X emission reduction expected from introducing wind and solar power will be..., 2011 Comments at 13 (citing Katzenstein, W., and Jay Apt. Air Emissions Due To Wind and Solar...

  11. Banter for Breakfast: Youth, Power and Resistance in an (Un)Regulated Space.

    ERIC Educational Resources Information Center

    Bogad, Lesley

    1998-01-01

    A weekly discussion group for high school students, held at a church before school, provided youth with a place to make connections across differences and to engage in stimulating debate with peers. Anecdotes illustrate how the youth group resisted unfair practices of adult authority while failing to openly recognize the power dynamics within the…

  12. Engine combustion control via fuel reactivity stratification

    SciTech Connect

    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).

  13. Engine combustion control via fuel reactivity stratification

    SciTech Connect

    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).

  14. 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).

  15. 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.

  16. 6-Shogaol enhances renal carcinoma Caki cells to TRAIL-induced apoptosis through reactive oxygen species-mediated cytochrome c release and down-regulation of c-FLIP(L) expression.

    PubMed

    Han, Min Ae; Woo, Seon Min; Min, Kyoung-jin; Kim, Shin; Park, Jong-Wook; Kim, Dong Eun; Kim, Sang Hyun; Choi, Yung Hyun; Kwon, Taeg Kyu

    2015-02-25

    6-Shogaol, a potent bioactive compound in ginger (Zingiber officinale Roscoe), has been reported for anti-inflammatory and anti-cancer activity. In this study, we investigated the effect of 6-shogaol to enhance tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis. The combined treatment with 6-shogaol and TRAIL markedly induces apoptosis in various cancer cells (renal carcinoma Caki cells, breast carcinoma MDA-MB-231 cells and glioma U118MG cells), but not in normal mesangial cells and normal mouse kidney cells. 6-Shogaol reduced the mitochondrial membrane potential (MMP) and released cytochrome c from mitochondria to cytosol via Bax activation. Furthermore, we found that 6-shogaol induced down-regulation of c-FLIP(L) expression at the post-translational levels and the overexpression of c-FLIP(L) markedly inhibited 6-shogaol plus TRAIL-induced apoptosis. Moreover, 6-shogaol increased reactive oxygen species (ROS) production in Caki cells. Pretreatment with ROS scavengers attenuated 6-shogaol plus TRAIL-induced apoptosis through inhibition of MMP reduction and down-regulation of c-FLIP(L) expression. In addition, 6-gingerol, another phenolic alkanone isolated from ginger, did not enhance TRAIL-induced apoptosis and down-regulate c-FLIP(L) expression. Taken together, our results demonstrated that 6-shogaol enhances TRAIL-mediated apoptosis in renal carcinoma Caki cells via ROS-mediated cytochrome c release and down-regulation of c-FLIP(L) expression. PMID:25619640

  17. Re-Examining first principles of regulation: NRG power marketing, LLC v. Maine public utilities Commission

    SciTech Connect

    Haskell, Mark R.

    2010-03-15

    Maine PUC and Morgan Stanley have resolved some of the key issues facing the energy industry. The Supreme Court has plainly and directly in both cases reaffirmed the central role that private contracts play in the energy industry and set terms to balance the need to secure long-term investment with the public interest that lies at the heart of the Federal Power Act. (author)

  18. 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. PMID:26416275

  19. Performance and power regulation characteristics of two aileron-controlled rotors and a pitchable tip-controlled rotor on the Mod-O turbine

    NASA Technical Reports Server (NTRS)

    Corrigan, Robert D.; Ensworth, Clinton B. F., III; Miller, Dean R.

    1987-01-01

    Tests were conducted on the DOE/NASA mod-0 horizontal axis wind turbine to compare and evaluate the performance and the power regulation characteristics of two aileron-controlled rotors and a pitchable tip-controlled rotor. The two aileron-controlled rotor configurations used 20 and 38 percent chord ailerons, while the tip-controlled rotor had a pitchable blade tip. The ability of the control surfaces to regulate power was determined by measuring the change in power caused by an incremental change in the deflection angle of the control surface. The data shows that the change in power per degree of deflection angle for the tip-controlled rotor was four times the corresponding value for the 2- percent chord ailerons. The root mean square power deviation about a power setpoint was highest for the 20 percent chord aileron, and lowest for the 38 percent chord aileron.

  20. 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. PMID:19210061

  1. Regulated 50 V PCU Product For Low/Medium Power Telecom Satellites

    NASA Astrophysics Data System (ADS)

    Soto, A.; Simon, P.

    2011-10-01

    This paper explains the challenges faced in the design of a high reliable, high performance PCU for 15 years, small-medium power telecom missions. The fulfilment of ECSS standards and required reliability in a cost driven mission is a challenge to meet mass and cost requirements. The paper describes the main design solutions that enable the fulfilment of requirements. These design solutions are result of a careful analysis of other important requirements and design issues like high SA capacitance, battery interface, bus quality, bus output impedance, TDMA operation, heat dissipation, thermal interface and protections.

  2. 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.

  3. 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

  4. A steam-water distribution matrix equation of the whole thermal system for coal-fired power plant and its general construction regulations

    SciTech Connect

    Zhang Chunfa; Yan Shunlin; Fan Hansong; Cao Xianchang; Wu Chunsheng

    1999-07-01

    In this paper the authors provide a steam-water distribution equation of the whole thermal system for coal-fired power plant and its general construction regulations. The use of the equation may simplify traditional thermal calculation of coal-fired power plant. And the equation's analytic character provides a strict base of theory and a new method for energy conservation of coal-fired power plant and especially for the research of local ration analysis for thermal system's energy conservation potential.

  5. Real-time fMRI brain-computer interface: development of a “motivational feedback” subsystem for the regulation of visual cue reactivity

    PubMed Central

    Sokunbi, Moses O.; Linden, David E. J.; Habes, Isabelle; Johnston, Stephen; Ihssen, Niklas

    2014-01-01

    Here we present a novel neurofeedback subsystem for the presentation of motivationally relevant visual feedback during the self-regulation of functional brain activation. Our “motivational neurofeedback” approach uses functional magnetic resonance imaging (fMRI) signals elicited by visual cues (pictures) and related to motivational processes such as craving or hunger. The visual feedback subsystem provides simultaneous feedback through these images as their size corresponds to the magnitude of fMRI signal change from a target brain area. During self-regulation of cue-evoked brain responses, decreases and increases in picture size thus provide real motivational consequences in terms of cue approach vs. cue avoidance, which increases face validity of the approach in applied settings. Further, the outlined approach comprises of neurofeedback (regulation) and “mirror” runs that allow to control for non-specific and task-unrelated effects, such as habituation or neural adaptation. The approach was implemented in the Python programming language. Pilot data from 10 volunteers showed that participants were able to successfully down-regulate individually defined target areas, demonstrating feasibility of the approach. The newly developed visual feedback subsystem can be integrated into protocols for imaging-based brain-computer interfaces (BCI) and may facilitate neurofeedback research and applications into healthy and dysfunctional motivational processes, such as food craving or addiction. PMID:25505392

  6. Real-time fMRI brain-computer interface: development of a "motivational feedback" subsystem for the regulation of visual cue reactivity.

    PubMed

    Sokunbi, Moses O; Linden, David E J; Habes, Isabelle; Johnston, Stephen; Ihssen, Niklas

    2014-01-01

    Here we present a novel neurofeedback subsystem for the presentation of motivationally relevant visual feedback during the self-regulation of functional brain activation. Our "motivational neurofeedback" approach uses functional magnetic resonance imaging (fMRI) signals elicited by visual cues (pictures) and related to motivational processes such as craving or hunger. The visual feedback subsystem provides simultaneous feedback through these images as their size corresponds to the magnitude of fMRI signal change from a target brain area. During self-regulation of cue-evoked brain responses, decreases and increases in picture size thus provide real motivational consequences in terms of cue approach vs. cue avoidance, which increases face validity of the approach in applied settings. Further, the outlined approach comprises of neurofeedback (regulation) and "mirror" runs that allow to control for non-specific and task-unrelated effects, such as habituation or neural adaptation. The approach was implemented in the Python programming language. Pilot data from 10 volunteers showed that participants were able to successfully down-regulate individually defined target areas, demonstrating feasibility of the approach. The newly developed visual feedback subsystem can be integrated into protocols for imaging-based brain-computer interfaces (BCI) and may facilitate neurofeedback research and applications into healthy and dysfunctional motivational processes, such as food craving or addiction. PMID:25505392

  7. Vertical axis wind turbine power regulation through centrifugally pumped lift spoiling

    SciTech Connect

    Klimas, P.C.; Sladky, J.F. Jr.

    1985-01-01

    This paper describes an approach for lowering the rated windspeeds of Darrieus-type vertical axis wind turbines (VAWTs) whose blades are hollow aluminum extrusions. The blades, which when rotating act as centrifugal pumps, are fitted with a series of small perforations distributed along a portion of the blades' span. By valving the ends of the hollow blades, flow into the blade ends and out of the perforations may be controlled. This flow can induce premature aerodynamic stall on the blade elements, thereby reducing both the rated power of the turbine and its cost-of-energy. The concept has been proven on the Sandia National Laboratories 5-m diameter research VAWT and force balance and flow visualization wind tunnel tests have been conducted using a blade section designed for the VAWT application.

  8. 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.

  9. Routine hand doses vs monitoring regulations at a nuclear power plant.

    PubMed

    Huggins, T R; Watson, J E

    1984-04-01

    Hand radiation doses to workers at a nuclear power plant were monitored in this study to evaluate compliance with dose limits and to determine whether hand monitoring on a routine basis is necessary. Two hundred in-plant workers at Carolina Power and Light Co.'s H.B. Robinson Steam Electric Generating Plant were monitored with a ring TLD dosimeter on each hand for four months during routine plant operations. Study participants included plant operators, electricians, mechanics, health physics technicians and decontamination personnel. Ring dosimeters were worn, in addition to whole-body TLD dosimeters, at all times workers were in radiation control areas. Hand dosimeters were read on the same monthly schedule as the whole-body dosimeters to ensure correlation of exposure periods. The results of the analysis of hand-dose data obtained for these workers are summarized as follows: (1) No worker's hand dose exceeded 25% of the allowable quarterly dose. (2) Ninety-nine percent of hand doses were less than 600 mrem/month. (3) The highest hand dose observed in any month was 1074 mrem which if received for three months, is below regulatory dose limits and below the dose value where monitoring is required. The highest actual hand dose observed in the last quarter of 1981 was 1335 mrem. (4) Examination of hand dose to whole-body dose ratios revealed that if the whole-body dose limit is approached, hand doses are still below the dose level where monitoring is required. (5) A linear-regression analysis of hand and whole-body dose data provides the ability to predict hand doses from the whole-body doses. From these results, it is concluded that routine monitoring of hand doses is not required at the H.B. Robinson plant. This conclusion should also be applicable to routine operations at other similar nuclear plants. PMID:6706587

  10. 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

  11. Multifunctional reactive nanocomposite materials

    NASA Astrophysics Data System (ADS)

    Stamatis, Demitrios

    Many multifunctional nanocomposite materials have been developed for use in propellants, explosives, pyrotechnics, and reactive structures. These materials exhibit high reaction rates due to their developed reaction interfacial area. Two applications addressed in this work include nanocomposite powders prepared by arrested reactive milling (ARM) for burn rate modifiers and reactive structures. In burn rate modifiers, addition of reactive nanocomposite powders to aluminized propellants increases the burn rate of aluminum and thus the overall reaction rate of an energetic formulation. Replacing only a small fraction of aluminum by 8Al·MoO3 and 2B·Ti nanocomposite powders enhances the reaction rate with little change to the thermodynamic performance of the formulation; both the rate of pressure rise and maximum pressure measured in the constant volume explosion test increase. For reactive structures, nanocomposite powders with bulk compositions of 8Al·MoO3, 12Al·MoO3, and 8Al·3CuO were prepared by ARM and consolidated using a uniaxial die. Consolidated samples had densities greater than 90% of theoretical maximum density while maintaining their high reactivity. Pellets prepared using 8Al·MoO3 powders were ignited by a CO2 laser. Ignition delays increased at lower laser powers and greater pellet densities. A simplified numerical model describing heating and thermal initiation of the reactive pellets predicted adequately the observed effects of both laser power and pellet density on the measured ignition delays. To investigate the reaction mechanisms in nanocomposite thermites, two types of nanocomposite reactive materials with the same bulk compositions 8Al·MoO3 were prepared by different methods. One of the materials was manufactured by ARM and the other, so called metastable interstitial composite (MIC), by mixing of nano-scaled individual powders. Clear differences in the low-temperature redox reactions, welldetectable by differential scanning calorimetry

  12. [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. PMID:27112014

  13. SALT-RESPONSIVE ERF1 Regulates Reactive Oxygen Species–Dependent Signaling during the Initial Response to Salt Stress in Rice[W

    PubMed Central

    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

    2013-01-01

    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. PMID:23800963

  14. Nanoparticles up-regulate tumor necrosis factor-{alpha} and CXCL8 via reactive oxygen species and mitogen-activated protein kinase activation

    SciTech Connect

    Lee, Hye-Mi; Shin, D.-M.; Song, Hwan-Moon; Yuk, Jae-Min; Lee, Zee-Won; Lee, Sang-Hee; Hwang, Song Mei; Kim, Jin-Man; Lee, Chang-Soo Jo, Eun-Kyeong

    2009-07-15

    Evaluating the toxicity of nanoparticles is an integral aspect of basic and applied sciences, because imaging applications using traditional organic fluorophores are limited by properties such as photobleaching, spectral overlaps, and operational difficulties. This study investigated the toxicity of nanoparticles and their biological mechanisms. We found that nanoparticles, quantum dots (QDs), considerably activated the production of tumor necrosis factor (TNF)-{alpha} and CXC-chemokine ligand (CXCL) 8 through reactive oxygen species (ROS)- and mitogen-activated protein kinases (MAPKs)-dependent mechanisms in human primary monocytes. Nanoparticles elicited a robust activation of intracellular ROS, phosphorylation of p47phox, and nicotinamide adenine dinucleotide phosphate oxidase activities. Blockade of ROS generation with antioxidants significantly abrogated the QD-mediated TNF-{alpha} and CXCL8 expression in monocytes. The induced ROS generation subsequently led to the activation of MAPKs, which were crucial for mRNA and protein expression of TNF-{alpha} and CXCL8. Furthermore, confocal and electron microscopy analyses showed that internalized QDs were trapped in cytoplasmic vesicles and compartmentalized inside lysosomes. Finally, several repeated intravenous injections of QDs caused an increase in neutrophil infiltration in the lung tissues in vivo. These results provide novel insights into the QD-mediated chemokine induction and inflammatory toxic responses in vitro and in vivo.

  15. An Arabidopsis Zinc Finger Protein Increases Abiotic Stress Tolerance by Regulating Sodium and Potassium Homeostasis, Reactive Oxygen Species Scavenging and Osmotic Potential.

    PubMed

    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

  16. 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

  17. New tool to detect operation anomalies on automatic voltage regulator equipment of large power units; Generator simulator (GS)

    SciTech Connect

    Blanchet, P. )

    1990-01-01

    When large generating plants are installed on site remote from the consumer areas, the operation of network with correct margins of stability is conditioned by adjustment of automatic voltage regulator (AVR). Any spoiled deviation in normal operation or especially in abnormal run must be detected at first overhaul or first shutdown. Then, without delay, this new tool which is the generator simulator (GS) contributes to minimize the time necessary for failures investigation and to qualify again AVR equipment after repair. The two main objectives of this paper are: to qualify the AVR performances of power unit during the scheduled overhaul; and to lighten failures research into AVR system, avoiding faulty dismantling during the unit fortuitous shutdown.

  18. 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

  19. Eukaryotic translation initiation factor 5A2 regulates the migration and invasion of hepatocellular carcinoma cells via pathways involving reactive oxygen species.

    PubMed

    Liu, Rong-Rong; Lv, Ya-Su; Tang, Yue-Xiao; Wang, Yan-Fang; Chen, Xiao-Ling; Zheng, Xiao-Xiao; Xie, Shang-Zhi; Cai, Ying; Yu, Jun; Zhang, Xian-Ning

    2016-04-26

    Eukaryotic translation initiation factor 5A2 (eIF5A2) has been identified as a critical gene in tumor metastasis. Research has suggested that reactive oxygen species (ROS) serve as signaling molecules in cancer cell proliferation and migration. However, the mechanisms linking eIF5A2 and ROS are not fully understood. Here, we investigated the effects of ROS on the eIF5A2-induced epithelial-mesenchymal transition (EMT) and migration in six hepatocellular carcinoma (HCC) cell lines. Western hybridization, siRNA transfection, transwell migration assays, wound-healing assays, and immunofluorescence analysis were used. The protein levels of eIF5A2 in tumor and adjacent tissue samples from 90 HCC patients with detailed clinical, pathological, and clinical follow-up data were evaluated. Overexpression of eIF5A2 was found in cancerous tissues compared with adjacent tissues. We found that eIF5A2 overexpression in HCC was associated with reduced overall survival. Knockdown of eIF5A2 and intracellular reduction of ROS significantly suppressed the invasion and metastasis of HCC cells. Interestingly, N1-guanyl-1, 7-diaminoheptane (GC7) suppressed the intracellular ROS levels. After blocking the EMT, administration of GC7 or N-acetyl-L-cysteine did not reduce cell migration further. Based on the experimental data, we concluded that inhibition of eIF5A2 alters progression of the EMT to decrease the invasion and metastasis of HCC cells via ROS-related pathways. PMID:27028999

  20. 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. PMID:27068062

  1. 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. PMID:18242099

  2. Up-regulation of cytosolic phospholipase A{sub 2}{alpha} expression by N,N-diethyldithiocarbamate in PC12 cells; involvement of reactive oxygen species and nitric oxide

    SciTech Connect

    Akiyama, Nobuteru; Nabemoto, Maiko; Hatori, Yoshio; Nakamura, Hiroyuki; Hirabayashi, Tetsuya; Fujino, Hiromichi; Saito, Takeshi; Murayama, Toshihiko . E-mail: murayama@p.chiba-u.ac.jp

    2006-09-01

    Disulfiram (an alcohol-aversive drug) and related compounds are known to provoke several side effects involving behavioral and neurological complications. N,N-diethyldithiocarbamate (DDC) is considered as one of the main toxic species of disulfiram and acts as an inhibitor of superoxide dismutase. Since arachidonic acid (AA) formation is regulated by reactive oxygen species (ROS) and related to toxicity in neuronal cells, we investigated the effects of DDC on AA release and expression of the {alpha} type of cytosolic phospholipase A{sub 2} (cPLA{sub 2}{alpha}) in PC12 cells. Treatment with 80-120 {mu}M DDC that causes a moderate increase in ROS levels without cell toxicity stimulated cPLA{sub 2}{alpha} mRNA and its protein expression. The expression was mediated by extracellular-signal-regulated kinase (ERK1/2), one of the mitogen-activated protein kinases. Treatment with N {sup G} nitro-L-arginine methyl ester (an inhibitor of nitric oxide synthase, 1 mM) and oxy-hemoglobin (a scavenger of nitric oxide, 2 mg/mL) abolished the DDC-induced responses (ERK1/2 phosphorylation and cPLA{sub 2}{alpha} expression). We also showed DDC-induced up-regulation of the mRNA expression of lipocortin 1, an inhibitor of PLA{sub 2}. Furthermore, DDC treatment of the cells enhanced Ca{sup 2+}-ionophore-induced AA release in 30 min, although the effect was limited. Changes in AA metabolism in DDC-treated cells may have a potential role in mediating neurotoxic actions of disulfiram. In this study, we show the first to demonstrate the up-regulation of cPLA{sub 2}{alpha} expression by DDC treatment in neuronal cells.

  3. 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. PMID:27472382

  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 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

  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. Role of reactive oxygen species (ROS) in Mycobacterium bovis bacillus Calmette Guérin-mediated up-regulation of the human cathelicidin LL-37 in A549 cells.

    PubMed

    Méndez-Samperio, Patricia; Pérez, Aline; Torres, Laura

    2009-11-01

    The human cathelicidin LL-37 is one of the major antimicrobial peptides of the non-specific innate immune system in Mycobacterium tuberculosis infection. Its expression has been reported in epithelial cells infected with mycobacteria. However, the underlying molecular mechanisms by which Mycobacterium bovis bacillus Calmette-Guérin (BCG) triggers gene transcription of cathelicidin have not been elucidated. The objective of this study was to investigate the role of reactive oxygen species (ROS) in the M. bovis BCG-mediated up-regulation of the antimicrobial peptide cathelicidin LL-37 in human epithelial cells. Infection of A549 cells with M. bovis BCG led to a rapid ROS production. Importantly, blockade of ROS by preincubation of cells with the general ROS scavenger N-acetyl-l-cysteine (NAC) or the NADPH oxidase inhibitor DPI significantly reduced M. bovis BCG-induced up-regulation of cathelicidin LL-37 mRNA expression as determined by semi-quantitative RT-PCR or real-time PCR. In contrast, the xanthine oxidase inhibitor allopurinol did not affect M. bovis BCG-mediated up-regulation of cathelicidin LL-37 mRNA. Moreover, M. bovis BCG-mediated cathelicidin LL-37 mRNA expression was significantly blocked by the effect of the mitochondrial electron transfer chain subunit I inhibitor rotenone and H(2)O(2) scavenging enzyme catalase. In addition, M. bovis BCG-induced cathelicidin LL-37 protein secretion was inhibited by the addition of NAC, DPI, and the selective inhibitor of NADPH oxidase apocynin. Our results collectively indicate that M. bovis BCG-mediated up-regulation of cathelicidin is influenced by NADPH/ROS signaling pathways. In conclusion, these findings demonstrate a novel regulatory mechanism for the expression of cathelicidin LL-37 in human epithelial cells stimulated with M. bovis BCG. PMID:19729059

  7. Application of power-factor correction in the Tandem Mirror Experiment Upgrade magnet power supply

    SciTech Connect

    Corvin, W.C.

    1981-08-14

    The magnet power supply for the Tandem Mirror Experiment Upgrade (TMX Upgrade) contains 24 groups of dc rectifiers that feed the water-cooled magnets. Each group consists of five or less rectifiers, connected in series. All 24 are current-regulating, using phase-controlled bilateral thyristors in the rectifier transformer primaries. The electric utility system must furnish reactive power to these phase-controlled thyristors as well as to the cmmutating diodes in the rectifier bridges.

  8. MicroRNA-153/Nrf-2/GPx1 pathway regulates radiosensitivity and stemness of glioma stem cells via reactive oxygen species

    PubMed Central

    Yang, Wei; Shen, Yueming; Wei, Jing; Liu, Fenju

    2015-01-01

    Glioma stem cells (GSCs) exhibit stem cell properties and high resistance to radiotherapy. The main aim of our study was to determine the roles of ROS in radioresistance and stemness of GSCs. We found that microRNA (miR)-153 was down-regulated and its target gene nuclear factor-erythroid 2-related factor-2 (Nrf-2) was up-regulated in GSCs compared with that of non-GSCs glioma cells. The enhanced Nrf-2 expression increased glutathione peroxidase 1 (GPx1) transcription and decreased ROS level leading to radioresistance of GSCs. MiR-153 overexpression resulted in increased ROS production and radiosensitization of GSCs. Moreover, miR-153 overexpression led to decreased neurosphere formation capacity and stem cell marker expression, and induced differentiation through ROS-mediated activation of p38 MAPK in GSCs. Nrf-2 overexpression rescued the decreased stemness and radioresistance resulting from miR-153 overexpression in GSCs. In addition, miR-153 overexpression reduced tumorigenic capacity of GSCs and increased survival in mice bearing human GSCs. These findings demonstrated that miR-153 overexpression decreased radioresistance and stemness of GSCs through targeting Nrf-2/GPx1/ROS pathway. PMID:26124081

  9. Efficient air pollution regulation of coal-fired power in China

    NASA Astrophysics Data System (ADS)

    Feng, Therese

    This dissertation evaluates monetary external costs of electricity generation in the People's Republic of China and implications for efficient pollution control policy. It presents an integrated assessment of environmental damages of air emissions of a representative new coal-fired plant in urban areas of north and south China. The simulation evaluates the nature and magnitude of damages in China, transboundary effects in Japan and Korea, and global greenhouse gas warming impacts. The valuation is used to identify efficient abatement policy for Chinese plants over time; evaluate benefits of differentiated policies; and consider the importance of dynamic policy. Potential annual damages of operating a 600-MW power plant without controls in China today would be 43-45 million (U.S. 1995). Annual local damages of 37-40 million far exceed transboundary or greenhouse gas damages (1.4 million and $4.6 million respectively). The largest component of damages is the risk of human mortality and chronic morbidity from long-term exposure to fine particles. Efficient pollution control minimizes the sum of abatement costs and residual unabated damages. Because monetary damages reflect sufferers' willingness to pay to avoid environmental risks, the choice of efficient controls is fundamentally tied to societal values and preferences. The optimal path for Chinese abatement moves from modest dispersion measures at present to combined dispersion and emission controls approaching those of current-day United States, by 2050. The inclusion of transboundary and greenhouse damages does not substantively alter local policies. Welfare benefits are gained by differentiating abatement policy by pollutant, meteorological parameters, and by population density. An analysis of optimal one-time investment in abatement for a plant in a growing economy suggests that some investment is optimal at all incomes but no single level of abatement is suitable for all economies. Forward-looking policy

  10. Secretoglobin 1A1 and 1A1A Differentially Regulate Neutrophil Reactive Oxygen Species Production, Phagocytosis and Extracellular Trap Formation

    PubMed Central

    Côté, Olivier; Clark, Mary Ellen; Viel, Laurent; Labbé, Geneviève; Seah, Stephen Y. K.; Khan, Meraj A.; Douda, David N.; Palaniyar, Nades; Bienzle, Dorothee

    2014-01-01

    Secretoglobin family 1A member 1 (SCGB 1A1) is a small protein mainly secreted by mucosal epithelial cells of the lungs and uterus. SCGB 1A1, also known as club (Clara) cell secretory protein, represents a major constituent of airway surface fluid. The protein has anti-inflammatory properties, and its concentration is reduced in equine recurrent airway obstruction (RAO) and human asthma. RAO is characterized by reversible airway obstruction, bronchoconstriction and neutrophilic inflammation. Direct effects of SCGB 1A1 on neutrophil functions are unknown. We have recently identified that the SCGB1A1 gene is triplicated in equids and gives rise to two distinct proteins. In this study we produced the endogenously expressed forms of SCGBs (SCGB 1A1 and 1A1A) as recombinant proteins, and analyzed their effects on reactive oxygen species production, phagocytosis, chemotaxis and neutrophil extracellular trap (NET) formation ex vivo. We further evaluated whether NETs are present in vivo in control and inflamed lungs. Our data show that SCGB 1A1A but not SCGB 1A1 increase neutrophil oxidative burst and phagocytosis; and that both proteins markedly reduce neutrophil chemotaxis. SCGB 1A1A reduced chemotaxis significantly more than SCGB 1A1. NET formation was significantly reduced in a time- and concentration-dependent manner by SCGB 1A1 and 1A1A. SCGB mRNA in bronchial biopsies, and protein concentration in bronchoalveolar lavage fluid, was lower in horses with RAO. NETs were present in bronchoalveolar lavage fluid from horses with exacerbated RAO, but not in fluid from horses with RAO in remission or in challenged healthy horses. These findings indicate that SCGB 1A1 and 1A1A have overlapping and diverging functions. Considering disparities in the relative abundance of SCGB 1A1 and 1A1A in airway secretions of animals with RAO suggests that these functional differences may contribute to the pathogenesis of RAO and other neutrophilic inflammatory lung diseases. PMID:24777050

  11. 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. PMID:26608462

  12. Development of a widely applicable immunoassay for insulin in marine teleosts that regulates cross-reactivity using biotinylation and inhibits interference by plasma components.

    PubMed

    Andoh, Tadashi

    2016-01-15

    Amino acids are important insulinotropins in fish, and their effects vary between amino acids and fish species. Insulin levels are indicative of growth efficiency and stress levels in fish; however, interspecies comparisons of insulin levels are hampered by the difficulty of measuring insulin concentration in each fish. We developed a widely applicable competitive immunoassay using biotinylated yellowtail (Seriola quinqueradiata) insulin for measuring insulin in marine teleosts, including yellowtail and red seabream (Pagrus major), which are the most common species raised by aquaculture in Japan. Amino acid sequence substitution was limited at the ninth residue of the A-chain (A9) between these two species, and analysis of the primary structures of insulins from six phylogenetically far teleosts suggested that the sequences of yellowtail and red seabream insulins are identical to those of many teleosts, except the A9 residue. However, A9 is known to be an epitope that confers cross-reactive differences on insulin. We solved this problem through immunoreactive invalidation of this residue by biotinylation. The binding-inhibition curves of yellowtail and red seabream insulins were identical following the use of this technique. However, yellowtail and red seabream plasma was found to contain components that interfere with immunoassays. This problem was solved by the extraction of plasma using equal volume of acid-ethanol in yellowtail and by cooling at 0°C during the cross-reaction between the ligand and antibody in red seabream. Serially diluted plasma samples from both species exhibited linearity after these treatments. In a recovery test using plasma with added yellowtail insulin, the average recovery varied from 96.2% to 109.4%. A post-feeding rise in insulin was confirmed by this immunoassay in yellowtail, and peak of the rise was 39.8±7ng/ml at 1h postfeeding from 3.9±1.1ng/ml at 0h. This indicates that this assay is sufficient for measuring the baseline

  13. 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

  14. The Epithelial Anion Transporter Pendrin Is Induced by Allergy and Rhinovirus Infection, Regulates Airway Surface Liquid, and Increases Airway Reactivity and Inflammation in an Asthma Model1

    PubMed Central

    Nakagami, Yasuhiro; Favoreto, Silvio; Zhen, Guohua; Park, Sung-Woo; Nguyenvu, Louis T.; Kuperman, Douglas A.; Dolganov, Gregory M.; Huang, Xiaozhu; Boushey, Homer A.; Avila, Pedro C.; Erle, David J.

    2008-01-01

    Asthma exacerbations can be triggered by viral infections or allergens. The Th2 cytokines IL-13 and IL-4 are produced during allergic responses and cause increases in airway epithelial cell mucus, electrolyte and water secretion into the airway surface liquid (ASL). Since ASL dehydration can cause airway inflammation and obstruction, ion transporters could play a role in pathogenesis of asthma exacerbations. We previously reported that expression of the epithelial cell anion transporter pendrin is markedly increased in response to IL-13. Here we show that pendrin plays a role in allergic airway disease and in regulation of ASL thickness. Pendrin-deficient mice had less allergen-induced airway hyperreactivity and inflammation than control mice although other aspects of the Th2 response were preserved. In cultures of IL-13-stimulated mouse tracheal epithelial cells, pendrin deficiency caused an increase in ASL thickness, suggesting that reductions in allergen-induced hyperreactivity and inflammation in pendrin-deficient mice result from improved ASL hydration. To determine whether pendrin might also play a role in virus-induced exacerbations of asthma, we measured pendrin mRNA expression in human subjects with naturally occurring common colds caused by rhinovirus and found a 4.9-fold-increase in mean expression during colds. Studies of cultured human bronchial epithelial cells indicated that this increase could be explained by the combined effects of rhinovirus and IFN-γ, a Th1 cytokine induced during virus infection. We conclude that pendrin regulates ASL thickness and may be an important contributor to asthma exacerbations induced by viral infections or allergens. PMID:18641360

  15. 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.

  16. 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.

  17. NADPH-dependent thioredoxin reductase C plays a role in nonhost disease resistance against Pseudomonas syringae pathogens by regulating chloroplast-generated reactive oxygen species.

    PubMed

    Ishiga, Yasuhiro; Ishiga, Takako; Ikeda, Yoko; Matsuura, Takakazu; Mysore, Kirankumar S

    2016-01-01

    Chloroplasts are cytoplasmic organelles for photosynthesis in eukaryotic cells. In addition, recent studies have shown that chloroplasts have a critical role in plant innate immunity against invading pathogens. Hydrogen peroxide is a toxic by-product from photosynthesis, which also functions as a signaling compound in plant innate immunity. Therefore, it is important to regulate the level of hydrogen peroxide in response to pathogens. Chloroplasts maintain components of the redox detoxification system including enzymes such as 2-Cys peroxiredoxins (2-Cys Prxs), and NADPH-dependent thioredoxin reductase C (NTRC). However, the significance of 2-Cys Prxs and NTRC in the molecular basis of nonhost disease resistance is largely unknown. We evaluated the roles of Prxs and NTRC using knock-out mutants of Arabidopsis in response to nonhost Pseudomonas syringae pathogens. Plants lacking functional NTRC showed localized cell death (LCD) accompanied by the elevated accumulation of hydrogen peroxide in response to nonhost pathogens. Interestingly, the Arabidopsis ntrc mutant showed enhanced bacterial growth and disease susceptibility of nonhost pathogens. Furthermore, the expression profiles of the salicylic acid (SA) and jasmonic acid (JA)-mediated signaling pathways and phytohormone analyses including SA and JA revealed that the Arabidopsis ntrc mutant shows elevated JA-mediated signaling pathways in response to nonhost pathogen. These results suggest the critical role of NTRC in plant innate immunity against nonhost P. syringae pathogens. PMID:27168965

  18. NADPH-dependent thioredoxin reductase C plays a role in nonhost disease resistance against Pseudomonas syringae pathogens by regulating chloroplast-generated reactive oxygen species

    PubMed Central

    Ishiga, Takako; Ikeda, Yoko; Matsuura, Takakazu; Mysore, Kirankumar S.

    2016-01-01

    Chloroplasts are cytoplasmic organelles for photosynthesis in eukaryotic cells. In addition, recent studies have shown that chloroplasts have a critical role in plant innate immunity against invading pathogens. Hydrogen peroxide is a toxic by-product from photosynthesis, which also functions as a signaling compound in plant innate immunity. Therefore, it is important to regulate the level of hydrogen peroxide in response to pathogens. Chloroplasts maintain components of the redox detoxification system including enzymes such as 2-Cys peroxiredoxins (2-Cys Prxs), and NADPH-dependent thioredoxin reductase C (NTRC). However, the significance of 2-Cys Prxs and NTRC in the molecular basis of nonhost disease resistance is largely unknown. We evaluated the roles of Prxs and NTRC using knock-out mutants of Arabidopsis in response to nonhost Pseudomonas syringae pathogens. Plants lacking functional NTRC showed localized cell death (LCD) accompanied by the elevated accumulation of hydrogen peroxide in response to nonhost pathogens. Interestingly, the Arabidopsis ntrc mutant showed enhanced bacterial growth and disease susceptibility of nonhost pathogens. Furthermore, the expression profiles of the salicylic acid (SA) and jasmonic acid (JA)-mediated signaling pathways and phytohormone analyses including SA and JA revealed that the Arabidopsis ntrc mutant shows elevated JA-mediated signaling pathways in response to nonhost pathogen. These results suggest the critical role of NTRC in plant innate immunity against nonhost P. syringae pathogens. PMID:27168965

  19. 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. PMID:22168107

  20. 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. PMID:25704056

  1. 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.

  2. 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.

  3. The antioxidative power AP--A new quantitative time dependent (2D) parameter for the determination of the antioxidant capacity and reactivity of different plants.

    PubMed

    Jung, Katinka; Richter, J; Kabrodt, K; Lücke, I M; Schellenberg, I; Herrling, Th

    2006-03-13

    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 1AU 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. PMID:16490383

  4. Expression of the receptor for complement C5a (CD88) is up-regulated on reactive astrocytes, microglia, and endothelial cells in the inflamed human central nervous system.

    PubMed Central

    Gasque, P.; Singhrao, S. K.; Neal, J. W.; Götze, O.; Morgan, B. P.

    1997-01-01

    C5a receptor (C5aR, CD88) is a receptor originally described on neutrophils and monocyte-macrophages but recently found on hepatocytes, epithelial cells, endothelial cells, and tissue mast cells. We recently reported that human fetal astrocytes expressed a functional C5aR in vitro. Here we examine C5aR expression in adult brain cultures by immunostaining with six different anti-C5aRs and show that C5aR is expressed constitutively by astrocytes, microglia, and fibroblast-like cells but not by oligodendrocytes. In fetal brain cultures we confirmed that astrocytes constitutively expressed C5aR and demonstrated that fetal microglia and fibroblast-like cells but not oligodendrocytes and neurones expressed C5aR. Incubation with inflammatory cytokines (interferon gamma, interleukin-1, and tumor necrosis factor alpha) or phorbol ester failed to induce or up-regulate C5aR expression on fetal or adult brain cells. Immunohistochemistry was performed to determine the expression and distribution of C5aR in the normal and inflamed brain. In the normal brain C5aR was minimally expressed, whereas in inflamed brains from a variety of pathologies, C5aR expression was greatly up-regulated on reactive astrocytes and microglia and to a lesser extent on endothelial cells. We propose that expression of C5aR is a marker of central nervous system inflammation, and that C5aR expression on brain cells in inflammation plays an important role in cell activation and recruitment (gliosis). Images Figure 1 Figure 2 Figure 3 PMID:9006319

  5. 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.

  6. Dynamics of reactive high-power impulse magnetron sputtering discharge studied by time- and space-resolved optical emission spectroscopy and fast imaging

    SciTech Connect

    Hala, M.; Viau, N.; Zabeida, O.; Klemberg-Sapieha, J. E.; Martinu, L.

    2010-02-15

    Time- and space-resolved optical emission spectroscopy and fast imaging were used for the investigation of the plasma dynamics of high-power impulse magnetron sputtering discharges. 200 {mu}s pulses with a 50 Hz repetition frequency were applied to a Cr target in Ar, N{sub 2}, and N{sub 2}/Ar mixtures and in a pressure range from 0.7 to 2.66 Pa. The power density peaked at 2.2-6 kW cm{sup -2}. Evidence of dominating self-sputtering was found for all investigated conditions. Up to four different discharge phases within each pulse were identified: (i) the ignition phase, (ii) the high-current metal-dominated phase, (iii) the transient phase, and (iv) the low-current gas-dominated phase. The emission of working gas excited by fast electrons penetrating the space in-between the electrodes during the ignition phase spread far outwards from the target at a speed of 24 km s{sup -1} in 1.3 Pa of Ar and at 7.5 km s{sup -1} in 1.3 Pa of N{sub 2}. The dense metal plasma created next to the target propagated in the reactor at a speed ranging from 0.7 to 3.5 km s{sup -1}, depending on the working gas composition and the pressure. In fact, it increased with higher N{sub 2} concentration and lower pressure. The form of the propagating plasma wave changed from a hemispherical shape in Ar, to a droplike shape extending far from the target in N{sub 2}. An important N{sub 2} emission rise in the latter case was detected during the transition at the end of the metal-dominated phase.

  7. KCa3.1/IK1 Channel Regulation by cGMP-Dependent Protein Kinase (PKG) via Reactive Oxygen Species and CaMKII in Microglia: An Immune Modulating Feedback System?

    PubMed

    Ferreira, Roger; Wong, Raymond; Schlichter, Lyanne C

    2015-01-01

    The intermediate conductance Ca(2+)-activated K(+) channel, KCa3.1 (IK1/SK4/KCNN4) is widely expressed in the innate and adaptive immune system. KCa3.1 contributes to proliferation of activated T lymphocytes, and in CNS-resident microglia, it contributes to Ca(2+) signaling, migration, and production of pro-inflammatory mediators (e.g., reactive oxygen species, ROS). KCa3.1 is under investigation as a therapeutic target for CNS disorders that involve microglial activation and T cells. However, KCa3.1 is post-translationally regulated, and this will determine when and how much it can contribute to cell functions. We previously found that KCa3.1 trafficking and gating require calmodulin (CaM) binding, and this is inhibited by cAMP kinase (PKA) acting at a single phosphorylation site. The same site is potentially phosphorylated by cGMP kinase (PKG), and in some cells, PKG can increase Ca(2+), CaM activation, and ROS. Here, we addressed KCa3.1 regulation through PKG-dependent pathways in primary rat microglia and the MLS-9 microglia cell line, using perforated-patch recordings to preserve intracellular signaling. Elevating cGMP increased both the KCa3.1 current and intracellular ROS production, and both were prevented by the selective PKG inhibitor, KT5823. The cGMP/PKG-evoked increase in KCa3.1 current in intact MLS-9 microglia was mediated by ROS, mimicked by applying hydrogen peroxide (H2O2), inhibited by a ROS scavenger (MGP), and prevented by a selective CaMKII inhibitor (mAIP). Similar results were seen in alternative-activated primary rat microglia; their KCa3.1 current required PKG, ROS, and CaMKII, and they had increased ROS production that required KCa3.1 activity. The increase in current apparently did not result from direct effects on the channel open probability (P o) or Ca(2+) dependence because, in inside-out patches from transfected HEK293 cells, single-channel activity was not affected by cGMP, PKG, H2O2 at normal or elevated intracellular Ca(2+). The

  8. KCa3.1/IK1 Channel Regulation by cGMP-Dependent Protein Kinase (PKG) via Reactive Oxygen Species and CaMKII in Microglia: An Immune Modulating Feedback System?

    PubMed Central

    Ferreira, Roger; Wong, Raymond; Schlichter, Lyanne C.

    2015-01-01

    The intermediate conductance Ca2+-activated K+ channel, KCa3.1 (IK1/SK4/KCNN4) is widely expressed in the innate and adaptive immune system. KCa3.1 contributes to proliferation of activated T lymphocytes, and in CNS-resident microglia, it contributes to Ca2+ signaling, migration, and production of pro-inflammatory mediators (e.g., reactive oxygen species, ROS). KCa3.1 is under investigation as a therapeutic target for CNS disorders that involve microglial activation and T cells. However, KCa3.1 is post-translationally regulated, and this will determine when and how much it can contribute to cell functions. We previously found that KCa3.1 trafficking and gating require calmodulin (CaM) binding, and this is inhibited by cAMP kinase (PKA) acting at a single phosphorylation site. The same site is potentially phosphorylated by cGMP kinase (PKG), and in some cells, PKG can increase Ca2+, CaM activation, and ROS. Here, we addressed KCa3.1 regulation through PKG-dependent pathways in primary rat microglia and the MLS-9 microglia cell line, using perforated-patch recordings to preserve intracellular signaling. Elevating cGMP increased both the KCa3.1 current and intracellular ROS production, and both were prevented by the selective PKG inhibitor, KT5823. The cGMP/PKG-evoked increase in KCa3.1 current in intact MLS-9 microglia was mediated by ROS, mimicked by applying hydrogen peroxide (H2O2), inhibited by a ROS scavenger (MGP), and prevented by a selective CaMKII inhibitor (mAIP). Similar results were seen in alternative-activated primary rat microglia; their KCa3.1 current required PKG, ROS, and CaMKII, and they had increased ROS production that required KCa3.1 activity. The increase in current apparently did not result from direct effects on the channel open probability (Po) or Ca2+ dependence because, in inside-out patches from transfected HEK293 cells, single-channel activity was not affected by cGMP, PKG, H2O2 at normal or elevated intracellular Ca2+. The regulation

  9. 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.

  10. 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

    ... AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74... applicable to translators, low power, and booster stations (except § 73.653—Operation of TV aural and...

  11. 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

    ... AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74... applicable to translators, low power, and booster stations (except § 73.653—Operation of TV aural and...

  12. 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

    ... AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74... applicable to translators, low power, and booster stations (except § 73.653—Operation of TV aural and...

  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

    ... AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74... applicable to translators, low power, and booster stations (except § 73.653—Operation of TV aural and...

  14. 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

    ... AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74... applicable to translators, low power, and booster stations (except § 73.653—Operation of TV aural and...

  15. 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.

  16. Effect of input power and gas pressure on the roughening and selective etching of SiO2/Si surfaces in reactive plasmas

    NASA Astrophysics Data System (ADS)

    Zhong, X. X.; Tam, E.; Huang, X. Z.; Colpo, P.; Rossi, F.; Ostrikov, K.

    2010-09-01

    We report on the application low-temperature plasmas for roughening Si surfaces which is becoming increasingly important for a number of applications ranging from Si quantum dots to cell and protein attachment for devices such as "laboratory on a chip" and sensors. It is a requirement that Si surface roughening is scalable and is a single-step process. It is shown that the removal of naturally forming SiO2 can be used to assist in the roughening of the surface using a low-temperature plasma-based etching approach, similar to the commonly used in semiconductor micromanufacturing. It is demonstrated that the selectivity of SiO2/Si etching can be easily controlled by tuning the plasma power, working gas pressure, and other discharge parameters. The achieved selectivity ranges from 0.4 to 25.2 thus providing an effective means for the control of surface roughness of Si during the oxide layer removal, which is required for many advance applications in bio- and nanotechnology.

  17. Effect of input power and gas pressure on the roughening and selective etching of SiO{sub 2}/Si surfaces in reactive plasmas

    SciTech Connect

    Zhong, X. X.; Huang, X. Z.; Tam, E.; Ostrikov, K.; Colpo, P.; Rossi, F.

    2010-09-15

    We report on the application low-temperature plasmas for roughening Si surfaces which is becoming increasingly important for a number of applications ranging from Si quantum dots to cell and protein attachment for devices such as 'laboratory on a chip' and sensors. It is a requirement that Si surface roughening is scalable and is a single-step process. It is shown that the removal of naturally forming SiO{sub 2} can be used to assist in the roughening of the surface using a low-temperature plasma-based etching approach, similar to the commonly used in semiconductor micromanufacturing. It is demonstrated that the selectivity of SiO{sub 2}/Si etching can be easily controlled by tuning the plasma power, working gas pressure, and other discharge parameters. The achieved selectivity ranges from 0.4 to 25.2 thus providing an effective means for the control of surface roughness of Si during the oxide layer removal, which is required for many advance applications in bio- and nanotechnology.

  18. Fracture Reactivation in Chemically Reactive Rock Systems

    NASA Astrophysics Data System (ADS)

    Eichhubl, P.; Hooker, J. N.

    2013-12-01

    Reactivation of existing fractures is a fundamental process of brittle failure that controls the nucleation of earthquake ruptures, propagation and linkage of hydraulic fractures in oil and gas production, and the evolution of fault and fracture networks and thus of fluid and heat transport in the upper crust. At depths below 2-3 km, and frequently shallower, brittle processes of fracture growth, linkage, and reactivation compete with chemical processes of fracture sealing by mineral precipitation, with precipitation rates similar to fracture opening rates. We recently found rates of fracture opening in tectonically quiescent settings of 10-20 μm/m.y., rates similar to euhedral quartz precipitation under these conditions. The tendency of existing partially or completely cemented fractures to reactivate will vary depending on strain rate, mineral precipitation kinetics, strength contrast between host rock and fracture cement, stress conditions, degree of fracture infill, and fracture network geometry. Natural fractures in quartzite of the Cambrian Eriboll Formation, NW Scotland, exhibit a complex history of fracture formation and reactivation, with reactivation involving both repeated crack-seal opening-mode failure and shear failure of fractures that formed in opening mode. Fractures are partially to completely sealed with crack-seal or euhedral quartz cement or quartz cement fragmented by shear reactivation. Degree of cementation controls the tendency of fractures for later shear reactivation, to interact elastically with adjacent open fractures, and their intersection behavior. Using kinematic, dynamic, and diagenetic criteria, we determine the sequence of opening-mode fracture formation and later shear reactivation. We find that sheared fracture systems of similar orientation display spatially varying sense of slip We attribute these inconsistent directions of shear reactivation to 1) a heterogeneous stress field in this highly fractured rock unit and 2

  19. Ion mass spectrometry investigations of the discharge during reactive high power pulsed and direct current magnetron sputtering of carbon in Ar and Ar/N{sub 2}

    SciTech Connect

    Schmidt, S.; Greczynski, G.; Jensen, J.; Hultman, L.; Czigany, Zs.

    2012-07-01

    Ion mass spectrometry was used to investigate discharges formed during high power impulse magnetron sputtering (HiPIMS) and direct current magnetron sputtering (DCMS) of a graphite target in Ar and Ar/N{sub 2} ambient. Ion energy distribution functions (IEDFs) were recorded in time-averaged and time-resolved mode for Ar{sup +}, C{sup +}, N{sub 2}{sup +}, N{sup +}, and C{sub x}N{sub y}{sup +} ions. An increase of N{sub 2} in the sputter gas (keeping the deposition pressure, pulse width, pulse frequency, and pulse energy constant) results for the HiPIMS discharge in a significant increase in C{sup +}, N{sup +}, and CN{sup +} ion energies. Ar{sup +}, N{sub 2}{sup +}, and C{sub 2}N{sup +} ion energies, in turn, did not considerably vary with the changes in working gas composition. The HiPIMS process showed higher ion energies and fluxes, particularly for C{sup +} ions, compared to DCMS. The time evolution of the plasma species was analyzed for HiPIMS and revealed the sequential arrival of working gas ions, ions ejected from the target, and later during the pulse-on time molecular ions, in particular CN{sup +} and C{sub 2}N{sup +}. The formation of fullerene-like structured CN{sub x} thin films for both modes of magnetron sputtering is explained by ion mass-spectrometry results and demonstrated by transmission electron microscopy as well as diffraction.

  20. Experiment and Simulation of Dynamic Voltage Regulation in Multiple Distributed Energy Resources Systems

    SciTech Connect

    Xu, Yan; Li, Fangxing; Kueck, John D; Rizy, D Tom

    2007-01-01

    Distributed energy (DE) resources are power sources located near load centers and equipped with power electronics converters to interface with the grid, therefore it is feasible for DE to provide reactive power (along with active power) locally for dynamic voltage regulation. In this paper, a synchronous condenser and a microturbine with an inverter interface are implemented in parallel in a distribution system to regulate the local voltage. Developed voltage control schemes for the inverter and the synchronous condenser are presented. Experimental results show that both the inverter and the synchronous condenser can regulate the local voltage instantaneously although the dynamic response of the inverter is much faster than the synchronous condenser. In a system with multiple DEs performing local voltage regulation, the interaction between the DEs is studied. The simulation results show the relationship between the voltages in the system and the reactive power required for the voltage regulation. Also, integrated voltage regulation (multiple DEs performing voltage regulation) can increase the voltage regulation capability of DEs and reduce the capital and operating costs.

  1. PYR/PYL/RCAR Abscisic Acid Receptors Regulate K+ and Cl− Channels through Reactive Oxygen Species-Mediated Activation of Ca2+ Channels at the Plasma Membrane of Intact Arabidopsis Guard Cells1[W][OPEN

    PubMed Central

    Wang, Yizhou; Chen, Zhong-Hua; Zhang, Ben; Hills, Adrian; Blatt, Michael R.

    2013-01-01

    The discovery of the START family of abscisic acid (ABA) receptors places these proteins at the front of a protein kinase/phosphatase signal cascade that promotes stomatal closure. The connection of these receptors to Ca2+ signals evoked by ABA has proven more difficult to resolve, although it has been implicated by studies of the pyrbactin-insensitive pyr1/pyl1/pyl2/pyl4 quadruple mutant. One difficulty is that flux through plasma membrane Ca2+ channels and Ca2+ release from endomembrane stores coordinately elevate cytosolic free Ca2+ concentration ([Ca2+]i) in guard cells, and both processes are facilitated by ABA. Here, we describe a method for recording Ca2+ channels at the plasma membrane of intact guard cells of Arabidopsis (Arabidopsis thaliana). We have used this method to resolve the loss of ABA-evoked Ca2+ channel activity at the plasma membrane in the pyr1/pyl1/pyl2/pyl4 mutant and show the consequent suppression of [Ca2+]i increases in vivo. The basal activity of Ca2+ channels was not affected in the mutant; raising the concentration of Ca2+ outside was sufficient to promote Ca2+ entry, to inactivate current carried by inward-rectifying K+ channels and to activate current carried by the anion channels, both of which are sensitive to [Ca2+]i elevations. However, the ABA-dependent increase in reactive oxygen species (ROS) was impaired. Adding the ROS hydrogen peroxide was sufficient to activate the Ca2+ channels and trigger stomatal closure in the mutant. These results offer direct evidence of PYR/PYL/RCAR receptor coupling to the activation by ABA of plasma membrane Ca2+ channels through ROS, thus affecting [Ca2+]i and its regulation of stomatal closure. PMID:23899646

  2. IL-1 receptor antagonist (IL-1Ra) does not inhibit the production of C-reactive protein or serum amyloid A protein by human primary hepatocytes. Differential regulation in normal and tumour cells.

    PubMed Central

    Gabay, C; Genin, B; Mentha, G; Iynedjian, P B; Roux-Lombard, P; Guerne, P A

    1995-01-01

    The synthesis of some class 1 acute-phase proteins (APP), including C-reactive protein (CRP) and serum amyloid A (SAA) protein is completely blocked by the IL-1 receptor antagonist (IL-1Ra), whereas the production of fibrinogen, a class 2 APP, is increased by IL-1Ra in hepatoma cells, but this has never been tested in human hepatocytes in primary culture. Since previous studies on the contributions of cytokine inhibitors in connective tissues diseases suggested that IL-1 and tumour necrosis factor-alpha (TNF-alpha) might play an important role in the regulation of CRP, we decided to examine in more detail the respective roles of IL-1 beta, IL-6, and TNF-alpha and their inhibitors in the production of APP by human primary hepatocytes versus the hepatoma cell line PLC/PRF/5. In the hepatoma cell line, IL-1 beta and/or TNF-alpha had synergistic effects with IL-6 on the production of CRP and SAA. In contrast, these cytokines were devoid of effect in normal hepatocytes. The production of fibrinogen was increased by IL-6 and decreased by IL-1 (and TNF-alpha) in both cell types. The secretion of CRP and SAA by primary hepatocytes incubated with a cytokine-rich mononuclear cell-conditioned medium was totally unaffected by IL-1Ra or anti-TNF-alpha antibodies. In contrast, the addition of IL-1Ra increased the production of fibrinogen by both hepatoma cells and primary hepatocytes incubated with the mononuclear cell-conditioned medium. We therefore conclude that IL-1 beta and TNF-alpha do not exert any significant effect on the synthesis of CRP and SAA by human primary hepatocytes. Images Fig. 6 PMID:7743670

  3. 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.

  4. Regulation of cyclooxygenase-2 and cytosolic phospholipase A2 gene expression by lipopolysaccharide through the RNA-binding protein HuR: involvement of NADPH oxidase, reactive oxygen species and mitogen-activated protein kinases

    PubMed Central

    Lin, Wei-Ning; Lin, Chih-Chung; Cheng, Hsin-Yi; Yang, Chuen-Mao

    2011-01-01

    BACKGROUND AND PURPOSE Lipopolysaccharide (LPS)-induced expression of cyclooxygenase-2 (COX-2) and cytosolic phospholipase A2 (cPLA2) has been implicated in several respiratory diseases. HuR is known to enhance the expression of genes by binding to 3′-untranslated region (3′-UTR) of mRNA and stabilizing mRNA. However, the exact mechanisms by which HuR affects the stability of mRNA and modulates LPS-induced COX-2 and cPLA2 expression in human tracheal smooth muscle cells (HTSMCs) are not known. EXPERIMENTAL APPROACH The expression of prostaglandin E2 (PGE2) was measured by ELISA, and pro-inflammatory proteins were determined by use of a promoter assay, PCR or Western blot analysis. Overexpression of siRNAs to knock down the target components was used to manipulate the expression of HuR. Release of reactive oxygen species (ROS) was detected by fluorescence dye. The activation of signalling components was assessed by comparing phosphorylation levels, localization of protein kinases or coimmunoprecipitation assay. KEY RESULTS LPS induced COX-2 and cPLA2 expression via post-translational regulation of mRNA stabilization, which were attenuated by transfection with HuR siRNA in HTSMCs. In addition, LPS-stimulated NADPH oxidase activation and ROS generation were attenuated by the NADPH oxidase inhibitors diphenyleneiodonium chloride (DPI) and apocynin (APO). Generation of ROS induced phosphorylation of p42/p44 mitogen-activated protein kinase (MAPK), p38 MAPK and JNK1/2, which was attenuated by DPI and APO and the ROS scavenger N-acetylcysteine. CONCLUSIONS AND IMPLICATIONS These results suggested that in HTSMCs, LPS-induced COX-2 and cPLA2 expression is mediated through NADPH oxidase/ROS-dependent MAPKs associated with HuR accumulation in the cytoplasm. Activated MAPKs may regulate the nucleocytoplasmic shuttling of HuR, and thus induce the cytoplasmic accumulation of HuR. PMID:21391979

  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. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Reactive Arthritis Diagnosis

    MedlinePlus

    ... Of Spondylitis The Heart In Spondyloarthritis Inflammatory vs. Mechanical Back ... Arthritis Symptoms Because there is no specific laboratory test for reactive arthritis, doctors sometimes find it difficult ...

  11. Dietary Magnesium Is Positively Associated With Skeletal Muscle Power and Indices of Muscle Mass and May Attenuate the Association Between Circulating C-Reactive Protein and Muscle Mass in Women.

    PubMed

    Welch, Ailsa A; Kelaiditi, Eirini; Jennings, Amy; Steves, Claire J; Spector, Tim D; MacGregor, Alexander

    2016-02-01

    Age-related loss of skeletal muscle mass and strength are risk factors for sarcopenia, osteoporosis, falls, fractures, frailty, and mortality. Dietary magnesium (Mg) could play a role in prevention of age-related loss of skeletal muscle mass, power, and strength directly through physiological mechanisms or indirectly through an impact on chronic low-grade inflammation, itself a risk factor for loss of skeletal muscle mass and strength. In a cross-sectional study of 2570 women aged 18 to 79 years, we examined associations between intakes of Mg, estimated using a food-frequency questionnaire (FFQ), dual-energy X-ray absorptiometry (DXA)-derived measures of muscle mass (fat-free mass as a percentage of body weight [FFM%], fat-free mass index [FFMI, kg/m(2) ]), leg explosive power (LEP), and grip strength (n = 949 only). We also examined associations between circulating hs-CRP (C-reactive protein) and muscle mass and LEP, and explored the potential attenuation of these relationships by Mg. We compared our findings with those of age and protein intake. Endpoints were calculated by quintile of Mg and adjusted for relevant confounders. Significant positive associations were found between a higher Mg and indices of skeletal muscle mass and LEP, and also with hs-CRP, after adjustment for covariates. Contrasting extreme quintiles of Mg intake showed differences of 2.6% for FFM% (p trend < 0.001), 0.4 kg/m(2) for FFMI (p trend = 0.005), and 19.6 watts/kg for LEP (p trend < 0.001). Compared with protein, these positive associations were 7 times greater for FFM% and 2.5 times greater for LEP. We also found that higher hs-CRP was negatively associated with skeletal muscle mass and, in statistical modeling, that a higher dietary Mg attenuated this negative relationship by 6.5%, with greater attenuation in women older than 50 years. No association was found between Mg and grip strength. Our results suggest that dietary magnesium may aid conservation of age

  12. Astrocyte reactivity and reactive astrogliosis: costs and benefits.

    PubMed

    Pekny, Milos; Pekna, Marcela

    2014-10-01

    Astrocytes are the most abundant cells in the central nervous system (CNS) that provide nutrients, recycle neurotransmitters, as well as fulfill a wide range of other homeostasis maintaining functions. During the past two decades, astrocytes emerged also as increasingly important regulators of neuronal functions including the generation of new nerve cells and structural as well as functional synapse remodeling. Reactive gliosis or reactive astrogliosis is a term coined for the morphological and functional changes seen in astroglial cells/astrocytes responding to CNS injury and other neurological diseases. Whereas this defensive reaction of astrocytes is conceivably aimed at handling the acute stress, limiting tissue damage, and restoring homeostasis, it may also inhibit adaptive neural plasticity mechanisms underlying recovery of function. Understanding the multifaceted roles of astrocytes in the healthy and diseased CNS will undoubtedly contribute to the development of treatment strategies that will, in a context-dependent manner and at appropriate time points, modulate reactive astrogliosis to promote brain repair and reduce the neurological impairment. PMID:25287860

  13. 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.

  14. Acquired reactive perforating collagenosis.

    PubMed

    Basak, P Y; Turkmen, C

    2001-01-01

    Acquired perforating disorder has been recognized as an uncommon distinct dermatosis in which altered collagen is eliminated through the epidermis. Several disorders accompanied by itching and scratching were reported to be associated with reactive perforating collagenosis. A 67-year-old white woman diagnosed as acquired reactive perforating collagenosis with poorly controlled diabetes mellitus and congestive cardiac failure is presented. PMID:11525959

  15. Thermophysical Reactivity Control of RBMK-1000

    NASA Astrophysics Data System (ADS)

    Vorobiev, Aleksander V.; Antonova, Aleksandra M.; Vinogradov, Maksim P.

    2016-02-01

    In this paper, viewed thermophysical characteristics of the moderator water graphite reactor RBMK. Indicated possibilities of controlling thermal state of graphite stack by regulation composition of the purge gas. Presents experimental results, but static thermal state characteristics of graphite moderator RBMK-1000. Developed a software code for integral characteristic engineering calculations, that determine value of margin reactivity reactor RBMK-1000, in the slow transients.

  16. Touch Attenuates Infants' Physiological Reactivity to Stress

    ERIC Educational Resources Information Center

    Feldman, Ruth; Singer, Magi; Zagoory, Orna

    2010-01-01

    Animal studies demonstrate that maternal touch and contact regulate infant stress, and handling during periods of maternal deprivation attenuates the stress response. To measure the effects of touch on infant stress reactivity during simulated maternal deprivation, 53 dyads were tested in two paradigms: still-face (SF) and still-face with maternal…

  17. Self-regulated frequent power pinch exercises: A non-orthotic technique for the treatment of old mallet deformity.

    PubMed

    Macionis, Valdas

    2015-01-01

    The utilization of an orthotic device to treat a mallet finger injury is common practice. This author describes a different approach to treating patients with an old mallet finger injury. The incorporation of frequent, self-regulated exercises without the use of an orthosis is described.--Victoria Priganc, PhD, OTR, CHT, CLT, Practice Forum Editor. PMID:26190029

  18. The reactivity worth of protactinium-233 inferred from measurements

    SciTech Connect

    Freeman, L.B.; Hecker, H.C.

    1982-02-01

    In a thorium-fueled reactor, the conversion of /sup 232/Th to /sup 233/U involves the intermediate nuclide /sup 233/Pa. This isotope has a significant reactivity effect in any thorium reactor, especially one with an important epithermal flux component. The light water breeder reactor, operating in the Shippingport atomic power station, is a /sup 233/U-Th reactor with about half the power produced at energies above thermal. The reactivity effect of full-power equilibrium /sup 233/Pa has been inferred from critical position measurements and control element reactivity worths to be approximately 2.5% delta rho in this reactor, confirming calculational predictions.

  19. Are Effortful and Reactive Control Unique Constructs in Young Children?

    ERIC Educational Resources Information Center

    Eisenberg, Nancy; Edwards, Alison; Spinrad, Tracy L.; Sallquist, Julie; Eggum, Natalie D.; Reiser, Mark

    2013-01-01

    The primary goal of this study was to examine whether effortful control (EC; effortful regulation), reactive undercontrol (IMP; e.g., impulsivity, speed of approach), and reactive overcontrol (NOV; inhibition to novelty) were 3 distinct constructs at 30 months (Time 1; n = 216), 42 months (Time 2; n = 192), and 54 months (Time 3; n = 168) of age.…

  20. Reactive metabolites and agranulocytosis.

    PubMed

    Uetrecht, J P

    1996-01-01

    Central to most hypotheses of the mechanism of idiosyncratic drug-induced blood dyscrasias is the involvement of reactive metabolites. In view of the reactive nature of the majority of such metabolites, it is likely that they are formed by, or in close proximity to the blood cells affected. The major oxidative system of neutrophils generates hypochlorous acid. We have demonstrated that the drugs associated with the highest incidence of agranulocytosis are oxidized to reactive metabolites by hypochlorous acid and/or activated neutrophils. There are many mechanisms by which such reactive metabolites could induce agranulocytosis. In the case of aminopyrine-induced agranulocytosis, most cases appear to involve drug-dependent anti-neutrophil antibodies, and these are likely to be induced by cell membrane antigens modified by the reactive metabolite of aminopyrine. The target of agranulocytosis associated with many other drugs is usually neutrophil precursors and may involve cytotoxicity or a cell-mediated immune reaction induced by a reactive metabolite. In the case of aplastic anaemia, there is evidence in some cases for involvement of cytotoxic T cells, which could either be induced by metabolites generated by neutrophils, or more likely, by reactive metabolites generated by stem cells. PMID:8987247