Performance Evaluation of UPQC under Nonlinear Unbalanced Load Conditions Using Synchronous Reference Frame Based Control

NASA Astrophysics Data System (ADS)

Kota, Venkata Reddy; Vinnakoti, Sudheer

2017-12-01

Today, maintaining Power Quality (PQ) is very important in the growing competent world. With new equipments and devices, new challenges are also being put before power system operators. Unified Power Quality Conditioner (UPQC) is proposed to mitigate many power quality problems and to improve the performance of the power system. In this paper, an UPQC with Fuzzy Logic controller for capacitor voltage balancing is proposed in Synchronous Reference Frame (SRF) based control with Modified Phased Locked Loop (MPLL). The proposed controller with SRF-MPLL based control is tested under non-linear and unbalanced load conditions. The system is developed in Matlab/Simulink and its performance is analyzed under various conditions like non-linear, unbalanced load and polluted supply voltage including voltage sag/swells. Active and reactive power flow in the system, power factor and %THD of voltages and currents before and after compensation are also analyzed in this work. Results prove the applicability of the proposed scheme for power quality improvement. It is observed that the fuzzy controller gives better performance than PI controller with faster capacitor voltage balancing and also improves the dynamic performance of the system.

Distribution-Connected PV's Response to Voltage Sags at Transmission-Scale

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mather, Barry; Ding, Fei

The ever increasing amount of residential- and commercial-scale distribution-connected PV generation being installed and operated on the U.S.'s electric power system necessitates the use of increased fidelity representative distribution system models for transmission stability studies in order to ensure the continued safe and reliable operation of the grid. This paper describes a distribution model-based analysis that determines the amount of distribution-connected PV that trips off-line for a given voltage sag seen at the distribution circuit's substation. Such sags are what could potentially be experienced over a wide area of an interconnection during a transmission-level line fault. The results of thismore » analysis show that the voltage diversity of the distribution system does cause different amounts of PV generation to be lost for differing severity of voltage sags. The variation of the response is most directly a function of the loading of the distribution system. At low load levels the inversion of the circuit's voltage profile results in considerable differences in the aggregated response of distribution-connected PV Less variation is seen in the response to specific PV deployment scenarios, unless pushed to extremes, and in the total amount of PV penetration attained. A simplified version of the combined CMPLDW and PVD1 models is compared to the results from the model-based analysis. Furthermore, the parameters of the simplified model are tuned to better match the determined response. The resulting tuning parameters do not match the expected physical model of the distribution system and PV systems and thus may indicate that another modeling approach would be warranted.« less

AlGaN/GaN high electron mobility transistors with selective area grown p-GaN gates

NASA Astrophysics Data System (ADS)

Yuliang, Huang; Lian, Zhang; Zhe, Cheng; Yun, Zhang; Yujie, Ai; Yongbing, Zhao; Hongxi, Lu; Junxi, Wang; Jinmin, Li

2016-11-01

We report a selective area growth (SAG) method to define the p-GaN gate of AlGaN/GaN high electron mobility transistors (HEMTs) by metal-organic chemical vapor deposition. Compared with Schottky gate HEMTs, the SAG p-GaN gate HEMTs show more positive threshold voltage (V th) and better gate control ability. The influence of Cp2Mg flux of SAG p-GaN gate on the AlGaN/GaN HEMTs has also been studied. With the increasing Cp2Mg from 0.16 μmol/min to 0.20 μmol/min, the V th raises from -0.67 V to -0.37 V. The maximum transconductance of the SAG HEMT at a drain voltage of 10 V is 113.9 mS/mm while that value of the Schottky HEMT is 51.6 mS/mm. The SAG method paves a promising way for achieving p-GaN gate normally-off AlGaN/GaN HEMTs without dry etching damage. Project supported by the National Natural Sciences Foundation of China (Nos. 61376090, 61306008) and the National High Technology Program of China (No. 2014AA032606).

TCSC based filtering and improvement of power quality

NASA Astrophysics Data System (ADS)

Arulvendhan, K.; Dilli srinivasan, J.; Vinil, M.

2018-04-01

Thyristor Controlled Series Capacitor (TCSC) as a dynamic system, also its competence in growing power allocation in transmission lines, can be used to improve different power system problems. TCSC’s dissimilar advantages can be categorised as steady-state and transient ones. During a fault, TCSC can increase power quality by reducing the current and benefit to keep the voltage as high as conceivable. In this paper, the application of TCSC to enrich one of the vital power quality issues, i.e., voltage sag is investigated. Different operating modes of TCSC have dissimilar influences on the voltage of the bus that the line armed with TCSC is connected to. Relocating to bypass mode upon manifestation of a fault is a significant feature of TCSC to advance voltage sag. The simulations on a trial network disclose these facts.

Dynamic Performance Evaluation of PV Integration

NASA Astrophysics Data System (ADS)

Gao, Ruilin; Jiang, Anwen; Chen, Hongjin

2018-03-01

Topics on adaptability of Grid-connected photovoltaic systems (GCPVS) under sag conditions has been proposed. A basic low-voltage-ride-through (LVRT) strategy widely used in engineering practice is taken in this paper and manages to ride through different sag conditions. The role of hardware protection has been discussed in detail. By simulation validated that the proposed GCPVS have strong adaptability

Electrical engineering unit for the reactive power control of the load bus at the voltage instability

NASA Astrophysics Data System (ADS)

Kotenev, A. V.; Kotenev, V. I.; Kochetkov, V. V.; Elkin, D. A.

2018-01-01

For the purpose of reactive power control error reduction and decrease of the voltage sags in the electric power system caused by the asynchronous motors started the mathematical model of the load bus was developed. The model was built up of the sub-models of the following elements: a transformer, a transmission line, a synchronous and an asynchronous loads and a capacitor bank load, and represents the automatic reactive power control system taking into account electromagnetic processes of the asynchronous motors started and reactive power changing of the electric power system elements caused by the voltage fluctuation. The active power/time and reactive power/time characteristics based on the recommended procedure of the equivalent electric circuit parameters calculation were obtained. The derived automatic reactive power control system was shown to eliminate the voltage sags in the electric power system caused by the asynchronous motors started.

Adaptability Evaluation of GCPVS under Voltage Sag

NASA Astrophysics Data System (ADS)

Wang, Li

2018-03-01

A basic LVRT strategy widely used in engineering practice is taken in this paper and manages to ride through both symmetrical and asymmetrical sag conditions. Precise current reference is calculate based on the reactive current curve in China National Grid Code, deration of current is realized in this way by eliminating NS current. The role of hardware protection has been discussed in detail.

Assessment of duration of the drive operation in the mode of kinetic energy recovery under power supply voltage sags in electrical grids of mechanical engineering enterprises

NASA Astrophysics Data System (ADS)

Shonin, O. B.; Novozhilov, N. G.

2017-02-01

Voltage sags in electric grids of mechanical engineering enterprises may lead to disconnection of important power consumers with variable frequency drives from the power grid and further interruption of the production process. The paper considers a sensorless V/f control system of еру induction motor drive under normal conditions and under voltage sags on the basis of a computer model of the drive and derivation of a formula for assessment of possible duration of the drive operation in the mode of controlled recovery of kinetic energy accumulated in rotating mass of the drive. Results of simulations have been used to validate results of calculations of the rotor velocity deceleration made in a closed form obtained from the equation reflecting the balance of torques. It is shown that results of calculations practically coincide with results of simulations in the range up to 5% of the velocity initial value. The proposed formula may be useful for estimation of the duration of the drive operation in the mode of recovery of kinetic energy depending on parameters of the motor and driven mechanisms.

Design of Interline Unified Power Quality Conditioner for Power Quality Disturbances using Simulink

NASA Astrophysics Data System (ADS)

Kumaraswamy, G.; Reddy, Y. Rajasekhar; Harikrishna, Ch.

2012-10-01

Proliferation of electronic equipment in commercial and industrial processes has resulted in increasingly sensitive electrical loads to be fed from power distribution system which introduce contamination to voltage and current waveforms at the point of common coupling of industrial loads. The unified power quality conditioner (UPQC) is connected between two different feeders (lines), hence this method of connection of the UPQC is called as Interline UPQC (IUPQC).This paper proposes a new connection for a UPQC to improve the power quality of two feeders in a distribution system. Interline Unified Power Quality Conditioner (IUPQC), specifically aims at the integration of series VSC and Shunt VSC to provide high quality power supply by means of voltage sag/swell compensation, harmonic elimination and power factor correction in a power distribution network, so that improved power quality can be made available at the point of common coupling. The structure, control and capability of the IUPQC are discussed in this paper. The efficiency of the proposed configuration has been verified through simulation using MATLAB/ SIMULINK.

Preparation of Power Distribution System for High Penetration of Renewable Energy Part I. Dynamic Voltage Restorer for Voltage Regulation Pat II. Distribution Circuit Modeling and Validation

NASA Astrophysics Data System (ADS)

Khoshkbar Sadigh, Arash

Part I: Dynamic Voltage Restorer In the present power grids, voltage sags are recognized as a serious threat and a frequently occurring power-quality problem and have costly consequence such as sensitive loads tripping and production loss. Consequently, the demand for high power quality and voltage stability becomes a pressing issue. Dynamic voltage restorer (DVR), as a custom power device, is more effective and direct solutions for "restoring" the quality of voltage at its load-side terminals when the quality of voltage at its source-side terminals is disturbed. In the first part of this thesis, a DVR configuration with no need of bulky dc link capacitor or energy storage is proposed. This fact causes to reduce the size of the DVR and increase the reliability of the circuit. In addition, the proposed DVR topology is based on high-frequency isolation transformer resulting in the size reduction of transformer. The proposed DVR circuit, which is suitable for both low- and medium-voltage applications, is based on dc-ac converters connected in series to split the main dc link between the inputs of dc-ac converters. This feature makes it possible to use modular dc-ac converters and utilize low-voltage components in these converters whenever it is required to use DVR in medium-voltage application. The proposed configuration is tested under different conditions of load power factor and grid voltage harmonic. It has been shown that proposed DVR can compensate the voltage sag effectively and protect the sensitive loads. Following the proposition of the DVR topology, a fundamental voltage amplitude detection method which is applicable in both single/three-phase systems for DVR applications is proposed. The advantages of proposed method include application in distorted power grid with no need of any low-pass filter, precise and reliable detection, simple computation and implementation without using a phased locked loop and lookup table. The proposed method has been verified by simulation and experimental tests under various conditions considering all possible cases such as different amounts of voltage sag depth (VSD), different amounts of point-on-wave (POW) at which voltage sag occurs, harmonic distortion, line frequency variation, and phase jump (PJ). Furthermore, the ripple amount of fundamental voltage amplitude calculated by the proposed method and its error is analyzed considering the line frequency variation together with harmonic distortion. The best and worst detection time of proposed method were measured 1ms and 8.8ms, respectively. Finally, the proposed method has been compared with other voltage sag detection methods available in literature. Part 2: Power System Modeling for Renewable Energy Integration: As power distribution systems are evolving into more complex networks, electrical engineers have to rely on software tools to perform circuit analysis. There are dozens of powerful software tools available in the market to perform the power system studies. Although their main functions are similar, there are differences in features and formatting structures to suit specific applications. This creates challenges for transferring power system circuit models data (PSCMD) between different software and rebuilding the same circuit in the second software environment. The objective of this part of thesis is to develop a Unified Platform (UP) to facilitate transferring PSCMD among different software packages and relieve the challenges of the circuit model conversion process. UP uses a commonly available spreadsheet file with a defined format, for any home software to write data to and for any destination software to read data from, via a script-based application called PSCMD transfer application. The main considerations in developing the UP are to minimize manual intervention and import a one-line diagram into the destination software or export it from the source software, with all details to allow load flow, short circuit and other analyses. In this study, ETAP, OpenDSS, and GridLab-D are considered, and PSCMD transfer applications written in MATLAB have been developed for each of these to read the circuit model data provided in the UP spreadsheet. In order to test the developed PSCMD transfer applications, circuit model data of a test circuit and a power distribution circuit from Southern California Edison (SCE) - a utility company - both built in CYME, were exported into the spreadsheet file according to the UP format. Thereafter, circuit model data were imported successfully from the spreadsheet files into above mentioned software using the PSCMD transfer applications developed for each software. After the SCE studied circuit is transferred into OpenDSS software using the proposed UP scheme and developed application, it has been studied to investigate the impacts of large-scale solar energy penetration. The main challenge of solar energy integration into power grid is its intermittency (i.e., discontinuity of output power) nature due to cloud shading of photovoltaic panels which depends on weather conditions. In order to conduct this study, OpenDSS time-series simulation feature, which is required due to intermittency of solar energy, is utilized. In this study, the impacts of intermittency of solar energy penetration, especially high-variability points, on voltage fluctuation and operation of capacitor bank and voltage regulator is provided. In addition, the necessity to interpolate and resample unequally spaced time-series measurement data and convert them to equally spaced time-series data as well as the effect of resampling time-interval on the amount of error is discussed. Two applications are developed in Matlab to do interpolation and resampling as well as to calculate the amount of error for different resampling time-intervals to figure out the suitable resampling time-interval. Furthermore, an approach based on cumulative distribution, regarding the length for lines/cables types and the power rating for loads, is presented to prioritize which loads, lines and cables the meters should be installed at to have the most effect on model validation.

Voltage profile program for the Kennedy Space Center electric power distribution system

NASA Technical Reports Server (NTRS)

1976-01-01

The Kennedy Space Center voltage profile program computes voltages at all busses greater than 1 Kv in the network under various conditions of load. The computation is based upon power flow principles and utilizes a Newton-Raphson iterative load flow algorithm. Power flow conditions throughout the network are also provided. The computer program is designed for both steady state and transient operation. In the steady state mode, automatic tap changing of primary distribution transformers is incorporated. Under transient conditions, such as motor starts etc., it is assumed that tap changing is not accomplished so that transformer secondary voltage is allowed to sag.

Energy storage and alternatives to improve train voltage on a mass transit system

NASA Astrophysics Data System (ADS)

Gordon, S. P.; Rorke, W. S.

1995-04-01

The wide separation of substations in the Bay Area Rapid Transit system's transbay tunnel contributes to voltage sag when power demand is high. In the future, expansions to the system will exacerbate this problem by increasing traffic density. Typically, this situation is remedied through the installation of additional substations to increase the system's power capacity. We have evaluated the efficacy of several alternatives to this approach - specifically, installation of an 8 megajoule energy storage system, modification of the existing substations, or reduction of the resistance of the running rails or the third rail. To support this analysis, we have developed a simple model of the traction power system in the tunnel. We have concluded that the storage system does not have sufficient capacity to deal with the expected voltage sags; in this application, the alternatives present more effective solutions. We have also investigated the potential impact of these system upgrades on expected future capital outlays by BART for traction power infrastructure additions. We have found that rail or substation upgrades may reduce the need for additional substations. These upgrades may also be effective on other parts of the BART system and on other traction power systems.

Electrical Power Quality - What's Behind the Outlet?

NASA Astrophysics Data System (ADS)

Baird, William H.; Secrest, Jeffery; Padgett, Clifford

2017-09-01

Although we may consider the power outlets in our homes to be nearly ideal voltage sources, a variety of influences in and around the home can cause departures from the nominal 60 Hz, 110-120 V root-mean-square (rms) of the North American grid. Even without instrumentation, we can see that a large motor starting from rest can be sufficient to cause lights to dim momentarily (voltage sag). This dimming is due to the inrush current drawn by a stationary motor, which may be several times the current drawn at operating speed. We prepared a voltage monitoring system using a voltage divider, the construction details of which we omit in the interest of safety.

Indirect current control with separate IZ drop compensation for voltage source converters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kanetkar, V.R.; Dawande, M.S.; Dubey, G.K.

1995-12-31

Indirect Current Control (ICC) of boost type Voltage Source Converters (VSCs) using separate compensation of line IZ voltage drop is presented. A separate bi-directional VSC is used to produce the compensation voltage. This simplifies the ICC regulator scheme as the power flow is controlled through single modulation index. Experimental verification is provided for bi-directional control of the power flow.

Large Capacity SMES for Voltage Dip Compensation

NASA Astrophysics Data System (ADS)

Iwatani, Yu; Saito, Fusao; Ito, Toshinobu; Shimada, Mamoru; Ishida, Satoshi; Shimanuki, Yoshio

Voltage dips of power grids due to thunderbolts, snow damage, and so on, cause serious damage to production lines of precision instruments, for example, semiconductors. In recent years, in order to solve this problem, uninterruptible power supply systems (UPS) are used. UPS, however, has small capacity, so a great number of UPS are needed in large factories. Therefore, we have manufactured the superconducting magnetic energy storage (SMES) system for voltage dip compensation able to protect loads with large capacity collectively. SMES has advantages such as space conservation, long lifetime and others. In field tests, cooperating with CHUBU Electric Power Co., Inc. we proved that SMES is valuable for compensating voltage dips. Since 2007, 10MVA SMES improved from field test machines has been running in a domestic liquid crystal display plant, and in 2008, it protected plant loads from a number of voltage dips. In this paper, we report the action principle and components of the improved SMES for voltage dip compensation, and examples of waveforms when 10MVA SMES compensated voltage dips.

Development of Multi-Functional Voltage Restore System

NASA Astrophysics Data System (ADS)

Suzuki, Satoshi; Ueda, Yoshinobu; Koganezawa, Takehisa; Ogihara, Yoshinori; Mori, Kenjiro; Fukazu, Naoaki

Recently, with the dawn of the electric deregulation, the installation of distributed generation with power electronics device has grown. This current causes a greater concern of power quality, primarily voltage disturbance for power companies, and their interest in power quality is peaking. Utilities are also interested in keeping their customers satisfied, as well as keeping them on-line and creating more revenue for the utility. As a countermeasure against the above surroundings, a variety type of devices based on power electronics has been developed to protect customers' load from power line voltage disturbance. One of them is the series type voltage restore. The series device is an active device, designed to provide a pure sinusoidal load voltage at all times, correcting voltage disturbance. Series type device compensates for voltage anomalies by inserting the ‘missing’ voltage onto the line through insertion transformer and inverter. This paper shows the setting guideline of target level to compensate voltage disturbance, that is, voltage dip, voltage harmonics, voltage imbalance and voltage flicker, and the design approach of the prototype of series voltage restores to accomplish the required compensation level. The prototype system gives satisfactory compensation performance through evaluation tests, which confirm the validity and effectiveness of the system.

Optimized Controller Design for a 12-Pulse Voltage Source Converter Based HVDC System

NASA Astrophysics Data System (ADS)

Agarwal, Ruchi; Singh, Sanjeev

2017-12-01

The paper proposes an optimized controller design scheme for power quality improvement in 12-pulse voltage source converter based high voltage direct current system. The proposed scheme is hybrid combination of golden section search and successive linear search method. The paper aims at reduction of current sensor and optimization of controller. The voltage and current controller parameters are selected for optimization due to its impact on power quality. The proposed algorithm for controller optimizes the objective function which is composed of current harmonic distortion, power factor, and DC voltage ripples. The detailed designs and modeling of the complete system are discussed and its simulation is carried out in MATLAB-Simulink environment. The obtained results are presented to demonstrate the effectiveness of the proposed scheme under different transient conditions such as load perturbation, non-linear load condition, voltage sag condition, and tapped load fault under one phase open condition at both points-of-common coupling.

Active-Matrix Organic Light Emission Diode Pixel Circuit for Suppressing and Compensating for the Threshold Voltage Degradation of Hydrogenated Amorphous Silicon Thin Film Transistors

NASA Astrophysics Data System (ADS)

Shin, Hee-Sun; Lee, Won-Kyu; Park, Sang-Guen; Kuk, Seung-Hee; Han, Min-Koo

2009-03-01

A new hydrogenated amorphous silicon (a-Si:H) thin film transistor (TFT) pixel circuit for active-matrix organic light emission diodes (AM-OLEDs), which significantly compensates the OLED current degradation by memorizing the threshold voltage of driving TFT and suppresses the threshold voltage shift of a-Si:H TFTs by negative bias annealing, is proposed and fabricated. During the first half of each frame, the driving TFT of the proposed pixel circuit supplies current to the OLED, which is determined by modified data voltage in the compensation scheme. The proposed pixel circuit was able to compensate the threshold voltage shift of the driving TFT as well as the OLED. During the remaining half of each frame, the proposed pixel circuit induces the recovery of the threshold voltage degradation of a-Si:H TFTs owing to the negative bias annealing. The experimental results show that the proposed pixel circuit was able to successfully compensate for the OLED current degradation and suppress the threshold voltage degradation of the driving TFT.

MATLAB Simulation of UPQC for Power Quality Mitigation Using an Ant Colony Based Fuzzy Control Technique

PubMed Central

Kumarasabapathy, N.; Manoharan, P. S.

2015-01-01

This paper proposes a fuzzy logic based new control scheme for the Unified Power Quality Conditioner (UPQC) for minimizing the voltage sag and total harmonic distortion in the distribution system consequently to improve the power quality. UPQC is a recent power electronic module which guarantees better power quality mitigation as it has both series-active and shunt-active power filters (APFs). The fuzzy logic controller has recently attracted a great deal of attention and possesses conceptually the quality of the simplicity by tackling complex systems with vagueness and ambiguity. In this research, the fuzzy logic controller is utilized for the generation of reference signal controlling the UPQC. To enable this, a systematic approach for creating the fuzzy membership functions is carried out by using an ant colony optimization technique for optimal fuzzy logic control. An exhaustive simulation study using the MATLAB/Simulink is carried out to investigate and demonstrate the performance of the proposed fuzzy logic controller and the simulation results are compared with the PI controller in terms of its performance in improving the power quality by minimizing the voltage sag and total harmonic distortion. PMID:26504895

Design and Implementation of Readout Circuit with Threshold Voltage Compensation on Glass Substrate for Touch Panel Applications

NASA Astrophysics Data System (ADS)

Lin, Yu-Ta; Ker, Ming-Dou; Wang, Tzu-Ming

2011-03-01

A new on-panel readout circuit with threshold voltage compensation for capacitive sensor in low temperature polycrystalline silicon (poly-Si) thin-film transistor (LTPS-TFT) process has been proposed. In order to compensate the threshold voltage variation from LTPS process variation, the proposed readout circuit applies a novel compensation approach with switch capacitor technique. In addition, a 4-bit analog-to-digital converter (ADC) is added to identify different sensed capacitor values and further enhances the overall resolution of touch panel.

Threshold-Voltage-Shift Compensation and Suppression Method Using Hydrogenated Amorphous Silicon Thin-Film Transistors for Large Active Matrix Organic Light-Emitting Diode Displays

NASA Astrophysics Data System (ADS)

Oh, Kyonghwan; Kwon, Oh-Kyong

2012-03-01

A threshold-voltage-shift compensation and suppression method for active matrix organic light-emitting diode (AMOLED) displays fabricated using a hydrogenated amorphous silicon thin-film transistor (TFT) backplane is proposed. The proposed method compensates for the threshold voltage variation of TFTs due to different threshold voltage shifts during emission time and extends the lifetime of the AMOLED panel. Measurement results show that the error range of emission current is from -1.1 to +1.7% when the threshold voltage of TFTs varies from 1.2 to 3.0 V.

Tulip-form variable-curvature mirrors: interferometry and field compensation

NASA Astrophysics Data System (ADS)

Lemaitre, Gerard R.; Mazzanti, Silvio; Ferrari, Marc

1998-07-01

Active Optics methods are now capable to provide variable curvature mirrors (VCMs) having controlled sags in the focal range from f/(infinity) to f/2.5. Those development have been carried out by the authors for the optical path equalizer dedicated to each Mersenne focus of the VLTI. The basic principle is to use VCMs as cat's eye mirrors in each delay line in order to achieve field compensations at the recombined Mersenne focii. During the VLTI development phase, cycloid form VCMs controlled by air pressure have been performed with a 10(superscript -4) mirror sag resolution. The cycloid form has been selected for the VLTi delay lines. However, other analytical solutions from circular plates elasticity theory have been found. Two thickness distributions lead to tulip form VCMs controlled by a central force. One of them, using a lineic reaction at the edge is the object of this paper. Active optics design, construction features, test and experimental He-Ne interferograms obtained with 16mm boundary aperture and 10mm clear aperture are presented. The mean aspect-ratio of the tulip from VCM is d/t(subscript 0.5) approximately equals 60, providing a focal zoom range from f/(infinity) to f/2.5. The experiment is carried out form f/(infinity) to f/5.

An inherent curvature-compensated voltage reference using non-linearity of gate coupling coefficient

NASA Astrophysics Data System (ADS)

Hande, Vinayak; Shojaei Baghini, Maryam

2015-08-01

A novel current-mode voltage reference circuit which is capable of generating sub-1 V output voltage is presented. The proposed architecture exhibits the inherent curvature compensation ability. The curvature compensation is achieved by utilizing the non-linear behavior of gate coupling coefficient to compensate non-linear temperature dependence of base-emitter voltage. We have also utilized the developments in CMOS process to reduce power and area consumption. The proposed voltage reference is analyzed theoretically and compared with other existing methods. The circuit is designed and simulated in 180 nm mixed-mode CMOS UMC technology which gives a reference level of 246 mV. The minimum required supply voltage is 1 V with maximum current drawn of 9.24 μA. A temperature coefficient of 9 ppm/°C is achieved over -25 to 125 °C temperature range. The reference voltage varies by ±11 mV across process corners. The reference circuit shows the line sensitivity of 0.9 mV/V with area consumption of 100 × 110 μm2

Improved fault ride through capability of DFIG based wind turbines using synchronous reference frame control based dynamic voltage restorer.

PubMed

Rini Ann Jerin, A; Kaliannan, Palanisamy; Subramaniam, Umashankar

2017-09-01

Fault ride through (FRT) capability in wind turbines to maintain the grid stability during faults has become mandatory with the increasing grid penetration of wind energy. Doubly fed induction generator based wind turbine (DFIG-WT) is the most popularly utilized type of generator but highly susceptible to the voltage disturbances in grid. Dynamic voltage restorer (DVR) based external FRT capability improvement is considered. Since DVR is capable of providing fast voltage sag mitigation during faults and can maintain the nominal operating conditions for DFIG-WT. The effectiveness of the DVR using Synchronous reference frame (SRF) control is investigated for FRT capability in DFIG-WT during both balanced and unbalanced fault conditions. The operation of DVR is confirmed using time-domain simulation in MATLAB/Simulink using 1.5MW DFIG-WT. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Topological formation of a multiply charged vortex in the Rb Bose-Einstein condensate: Effectiveness of the gravity compensation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumakura, M.; PRESTO, JST, 4-1-8 Honcho Kawaguchi, Saitama 332-0012; CREST, JST, 4-1-8 Honcho Kawaguchi, Saitama 332-0012

2006-06-15

In a Bose-Einstein condensate of {sup 87}Rb (F=2,m{sub F}=2) atoms we have topologically created a quantized vortex with a charge of 4 by reversing the magnetic field of the trap. Experimental conditions of reversal time and initial magnetic field strength for the successful vortex creation were restricted within narrower ranges, compared to those in the case of the {sup 23}Na condensate. The experimental difficulty was explained in terms of a non-negligible gravitational sag arising from its large atomic mass. We have successfully stabilized the vortex formation by compensating gravity with a blue-detuned laser beam.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stovall, J.P.; RIzy, D.T.; Kisner, R.A.

The 3M Company has developed a high-temperature low-sag conductor referred to as Aluminum- Conductor Composite-Reinforced or ACCR. The conductor uses an aluminum metal matrix material to replace the steel in conventional conductors so the core has a lower density and higher conductivity. The objective of this work is to accelerate the commercial acceptance by electric utilities of these new conductor designs by testing four representative conductor classes in controlled conditions. Overhead transmission lines use bare aluminum conductor strands wrapped around a steel core strands to transmit electricity. The typical cable is referred to as aluminum-conductor steel-reinforced (ACSR). The outer strandsmore » are aluminum, chosen for its conductivity, low weight, and low cost. The center strand is of steel for the strength required to support the weight without stretching the aluminum due to its ductility. The power density of a transmission corridor has been directly increased by increasing the voltage level. Transmission voltages have increased from 115-kV to 765- kV over the past 80 years. In the United States, further increasing the voltage level is not feasible at this point in time, so in order to further increase the power density of a transmission corridor, conductor designs that increase the current carrying capability have been examined. One of the key limiting factors in the design of a transmission line is the conductor sag which determines the clearance of the conductor above ground or underlying structures needed for electrical safety. Increasing the current carrying capability of a conductor increases the joule heating in the conductor which increases the conductor sag. A conductor designed for high-temperature and lowsag operation requires an engineered modification of the conductor materials. To make an advanced cable, the 3M Company solution has been the development of a composite conductor consisting of Nextel ceramic fibers to replace the steel core and an aluminum-zirconium alloy to improve the outer strands. The result is a cable that can carry more current than steelaluminum lines without sagging as much at higher temperatures. A unique facility called the Powerline Conductor Accelerated Testing (PCAT) Facility was built at ORNL for testing overhead conductors. The PCAT has been uniquely designed for testing overhead bare transmission line conductors at high currents and temperatures after they have been installed and tensioned to the manufacturer's specifications. The ability to operate a transmission line conductor in this manner does not exist elsewhere in the United States. Four classes of ACCR cable designed by 3M have been successfully test at ORNL – small, medium, large and small/compact. Based on these and other manufacturer tests, the 3M Company has successfully introduced the ACCR into the commercial market and has completed over twenty installations for utility companies.« less

1.55 µm high speed low chirp electroabsorption modulated laser arrays based on SAG scheme.

PubMed

Cheng, Yuanbing; Wang, Qi Jie; Pan, Jiaoqing

2014-12-15

We demonstrate a cost-effective 1.55 µm low chirp 4 × 25 Gbit/s electroabsorption modulated laser (EML) array with 0.8 nm channel spacing by varying ridge width of the lasers and using selective area growth (SAG) integration scheme. The devices for all the 4 channels within the EML array show uniform threshold currents around 18 mA and high SMSRs over 45 dB. The output optical power of each channel is about 9 mW at an injection current of 100 mA. The typical chirp value of single EML measured by a fiber resonance method varied from 2.2 to -4 as the bias voltage was increased from 0 V to 2.5 V. These results show that the EML array is a suitable light source for 100 Gbit/s optical transmissions.

Magnetic-Flux-Compensated Voltage Divider

NASA Technical Reports Server (NTRS)

Mata, Carlos T.

2005-01-01

A magnetic-flux-compensated voltage-divider circuit has been proposed for use in measuring the true potential across a component that is exposed to large, rapidly varying electric currents like those produced by lightning strikes. An example of such a component is a lightning arrester, which is typically exposed to currents of the order of tens of kiloamperes, having rise times of the order of hundreds of nanoseconds. Traditional voltage-divider circuits are not designed for magnetic-flux-compensation: They contain uncompensated loops having areas large enough that the transient magnetic fluxes associated with large transient currents induce spurious voltages large enough to distort voltage-divider outputs significantly. A drawing of the proposed circuit was not available at the time of receipt of information for this article. What is known from a summary textual description is that the proposed circuit would contain a total of four voltage dividers: There would be two mixed dividers in parallel with each other and with the component of interest (e.g., a lightning arrester), plus two mixed dividers in parallel with each other and in series with the component of interest in the same plane. The electrical and geometric configuration would provide compensation for induced voltages, including those attributable to asymmetry in the volumetric density of the lightning or other transient current, canceling out the spurious voltages and measuring the true voltage across the component.

Modelling and Simulation of Single-Phase Series Active Compensator for Power Quality Improvement

NASA Astrophysics Data System (ADS)

Verma, Arun Kumar; Mathuria, Kirti; Singh, Bhim; Bhuvaneshwari, G.

2017-10-01

A single-phase active series compensator is proposed in this work to reduce harmonic currents at the ac mains and to regulate the dc link voltage of a diode bridge rectifier (DBR) that acts as the front end converter for a voltage source inverter feeding an ac motor. This ac motor drive is used in any of the domestic, commercial or industrial appliances. Under fluctuating ac mains voltages, the dc link voltage of the DBR depicts wide variations and hence the ac motor is used at reduced rating as compared to its name-plate rating. The active series compensator proposed here provides dual functions of improving the power quality at the ac mains and regulating the dc link voltage thus averting the need for derating of the ac motor.

Ground difference compensating system

DOEpatents

Johnson, Kris W.; Akasam, Sivaprasad

2005-10-25

A method of ground level compensation includes measuring a voltage of at least one signal with respect to a primary ground potential and measuring, with respect to the primary ground potential, a voltage level associated with a secondary ground potential. A difference between the voltage level associated with the secondary ground potential and an expected value is calculated. The measured voltage of the at least one signal is adjusted by an amount corresponding to the calculated difference.

COS2025: Extending the Lifetime of the FUV channel of the Cosmic Origins Spectrograph to 2025

NASA Astrophysics Data System (ADS)

Rafelski, Marc; De Rosa, Gisella; Fischer, William J.; Fix, Mees; Fox, Andrew; Indriolo, Nick; James, Bethan; Magness, Camellia; Oliveira, Cristina M.; Penton, Steven V.; Plesha, Rachel; Roman-Duval, Julia; Sahnow, David J.; Sankrit, Ravi; Snyder, Elaine M.; Taylor, Joanna M.; White, James

2018-01-01

The Hubble Space Telescope's Cosmic Origins Spectrograph (COS) Far-Ultraviolet (FUV) microchannel plate detector's efficiency at converting incoming photons into detectable events decreases with usage. This depletion of the detector's gain (i.e. gain sag) results in unusable regions of the COS/FUV detector. In order to mitigate this gain sag, a number of strategies have been employed over the past 8 years of operations, ranging from moving to different lifetime positions, to managing the high voltage to extract a smaller amount of charge, to re-distributing the cenwave usage so that Ly-alpha does not produce a gain-sag hole in a given location. We are now at a point where none of the strategies above will, without any other changes, allow us to continue operating the COS/FUV detector to 2025. To address this a new COS2025 policy was developed, with the goal of retaining full science capability of COS/FUV to 2025. We present an overview of the COS2025 policy, which places restrictions on the G130M cenwaves allowed at Lifetime Position 4 (LP4). We also present a tool which allows users to visualize the COS/FUV wavelength ranges to help users prepare their proposals in the light of the restrictions on the G130M cenwaves.

Compensated count-rate circuit for radiation survey meter

DOEpatents

Todd, Richard A.

1981-01-01

A count-rate compensating circuit is provided which may be used in a portable Geiger-Mueller (G-M) survey meter to ideally compensate for counting loss errors in the G-M tube detector. In a G-M survey meter, wherein the pulse rate from the G-M tube is converted into a pulse rate current applied to a current meter calibrated to indicate dose rate, the compensated circuit generates and controls a reference voltage in response to the rate of pulses from the detector. This reference voltage is gated to the current-generating circuit at a rate identical to the rate of pulses coming from the detector so that the current flowing through the meter is varied in accordance with both the frequency and amplitude of the reference voltage pulses applied thereto so that the count rate is compensated ideally to indicate a true count rate within 1% up to a 50% duty cycle for the detector. A positive feedback circuit is used to control the reference voltage so that the meter output tracks true count rate indicative of the radiation dose rate.

Compensated count-rate circuit for radiation survey meter

DOEpatents

Todd, R.A.

1980-05-12

A count-rate compensating circuit is provided which may be used in a portable Geiger-Mueller (G-M) survey meter to ideally compensate for couting loss errors in the G-M tube detector. In a G-M survey meter, wherein the pulse rate from the G-M tube is converted into a pulse rate current applied to a current meter calibrated to indicate dose rate, the compensation circuit generates and controls a reference voltage in response to the rate of pulses from the detector. This reference voltage is gated to the current-generating circuit at a rate identical to the rate of pulses coming from the detector so that the current flowing through the meter is varied in accordance with both the frequency and amplitude of the reference voltage pulses applied thereto so that the count rate is compensated ideally to indicate a true count rate within 1% up to a 50% duty cycle for the detector. A positive feedback circuit is used to control the reference voltage so that the meter output tracks true count rate indicative of the radiation dose rate.

Serially-Connected Compensator for Eliminating the Unbalanced Three-Phase Voltage Impact on Wind Turbine Generators: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Z.; Hsu, P.; Muljadi, E.

2015-04-06

Untransposed transmission lines, unbalanced tap changer operations, and unbalanced loading in weak distribution lines can cause unbalanced-voltage conditions. The resulting unbalanced voltage at the point of interconnection affects proper gird integration and reduces the lifetime of wind turbines due to power oscillations, torque pulsations, mechanical stresses, energy losses, and uneven and overheating of the generator stator winding. This work investigates the dynamic impact of unbalanced voltage on the mechanical and electrical components of integrated Fatigue, Aerodynamics, Structures, and Turbulence (FAST) wind turbine generation systems (WTGs) of Type 1 (squirrel-cage induction generator) and Type 3 (doubly-fed induction generator). To alleviate thismore » impact, a serially-connected compensator for a three-phase power line is proposed to balance the wind turbine-side voltage. Dynamic simulation studies are conducted in MATLAB/Simulink to compare the responses of these two types of wind turbine models under normal and unbalanced-voltage operation conditions and demonstrate the effectiveness of the proposed compensator.« less

A Serially-Connected Compensator for Eliminating the Unbalanced Three-Phase Voltage Impact on Wind Turbine Generators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Ziping; Hsu, Ping; Muljadi, Eduard

2015-10-05

Untransposed transmission lines, unbalanced tap changer operations, and unbalanced loading in weak distribution lines can cause unbalanced-voltage conditions. The resulting unbalanced voltage at the point of interconnection affects proper gird integration and reduces the lifetime of wind turbines due to power oscillations, torque pulsations, mechanical stresses, energy losses, and uneven and overheating of the generator stator winding. This work investigates the dynamic impact of unbalanced voltage on the mechanical and electrical components of integrated Fatigue, Aerodynamics, Structures, and Turbulence (FAST) wind turbine generation systems (WTGs) of Type 1 (squirrel-cage induction generator) and Type 3 (doubly-fed induction generator). To alleviate thismore » impact, a serially-connected compensator for a three-phase power line is proposed to balance the wind turbine-side voltage. Dynamic simulation studies are conducted in MATLAB/Simulink to compare the responses of these two types of wind turbine models under normal and unbalanced-voltage operation conditions and demonstrate the effectiveness of the proposed compensator.« less

Improvement in Brightness Uniformity by Compensating for the Threshold Voltages of Both the Driving Thin-Film Transistor and the Organic Light-Emitting Diode for Active-Matrix Organic Light-Emitting Diode Displays

NASA Astrophysics Data System (ADS)

Ching-Lin Fan,; Hui-Lung Lai,; Jyu-Yu Chang,

2010-05-01

In this paper, we propose a novel pixel design and driving method for active-matrix organic light-emitting diode (AM-OLED) displays using low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs). The proposed threshold voltage compensation circuit, which comprised five transistors and two capacitors, has been verified to supply uniform output current by simulation work using the automatic integrated circuit modeling simulation program with integrated circuit emphasis (AIM-SPICE) simulator. The driving scheme of this voltage programming method includes four periods: precharging, compensation, data input, and emission. The simulated results demonstrate excellent properties such as low error rate of OLED anode voltage variation (<1%) and high output current. The proposed pixel circuit shows high immunity to the threshold voltage deviation characteristics of both the driving poly-Si TFT and the OLED.

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.

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.

Study on model current predictive control method of PV grid- connected inverters systems with voltage sag

NASA Astrophysics Data System (ADS)

Jin, N.; Yang, F.; Shang, S. Y.; Tao, T.; Liu, J. S.

2016-08-01

According to the limitations of the LVRT technology of traditional photovoltaic inverter existed, this paper proposes a low voltage ride through (LVRT) control method based on model current predictive control (MCPC). This method can effectively improve the photovoltaic inverter output characteristics and response speed. The MCPC method of photovoltaic grid-connected inverter designed, the sum of the absolute value of the predictive current and the given current error is adopted as the cost function with the model predictive control method. According to the MCPC, the optimal space voltage vector is selected. Photovoltaic inverter has achieved automatically switches of priority active or reactive power control of two control modes according to the different operating states, which effectively improve the inverter capability of LVRT. The simulation and experimental results proves that the proposed method is correct and effective.

Apparatus and Method for Compensating for Process, Voltage, and Temperature Variation of the Time Delay of a Digital Delay Line

NASA Technical Reports Server (NTRS)

Seefeldt, James (Inventor); Feng, Xiaoxin (Inventor); Roper, Weston (Inventor)

2013-01-01

A process, voltage, and temperature (PVT) compensation circuit and a method of continuously generating a delay measure are provided. The compensation circuit includes two delay lines, each delay line providing a delay output. The two delay lines may each include a number of delay elements, which in turn may include one or more current-starved inverters. The number of delay lines may differ between the two delay lines. The delay outputs are provided to a combining circuit that determines an offset pulse based on the two delay outputs and then averages the voltage of the offset pulse to determine a delay measure. The delay measure may be one or more currents or voltages indicating an amount of PVT compensation to apply to input or output signals of an application circuit, such as a memory-bus driver, dynamic random access memory (DRAM), a synchronous DRAM, a processor or other clocked circuit.

An 1.4 ppm/°C bandgap voltage reference with automatic curvature-compensation technique

NASA Astrophysics Data System (ADS)

Zhou, Zekun; Yu, Hongming; Shi, Yue; Zhang, Bo

2017-12-01

A high-precision Bandgap voltage reference (BGR) with a novel curvature-compensation scheme is proposed in this paper. The temperature coefficient (TC) can be automatically optimized with a built-in adaptive curvature-compensation technique, which is realized in a digitization control way. Firstly, an exponential curvature compensation method is adopted to reduce the TC in a certain degree, especially in low temperature range. Then, the temperature drift of BGR in higher temperature range can be further minimized by dynamic zero-temperature-coefficient point tracking with temperature changes. With the help of proposed adaptive signal processing, the output voltage of BGR can approximately maintain zero TC in a wider temperature range. Experiment results of the BGR proposed in this paper, which is implemented in 0.35-μm BCD process, illustrate that the TC of 1.4ppm/°C is realized under the power supply voltage of 3.6V and the power supply rejection of the proposed circuit is -67dB.

Evaluation of T2-weighted versus short-tau inversion recovery sagittal sequences in the identification and localization of canine intervertebral disc extrusion with low-field magnetic resonance imaging.

PubMed

Housley, Daniel; Caine, Abby; Cherubini, Giunio; Taeymans, Olivier

2017-07-01

Sagittal T2-weighted sequences (T2-SAG) are the foundation of spinal protocols when screening for the presence of intervertebral disc extrusion. We often utilize sagittal short-tau inversion recovery sequences (STIR-SAG) as an adjunctive screening series, and experience suggests that this combined approach provides superior detection rates. We hypothesized that STIR-SAG would provide higher sensitivity than T2-SAG in the identification and localization of intervertebral disc extrusion. We further hypothesized that the parallel evaluation of paired T2-SAG and STIR-SAG series would provide a higher sensitivity than could be achieved with either independent sagittal series when viewed in isolation. This retrospective diagnostic accuracy study blindly reviewed T2-SAG and STIR-SAG sequences from dogs (n = 110) with surgically confirmed intervertebral disc extrusion. A consensus between two radiologists found no significant difference in sensitivity between T2-SAG and STIR-SAG during the identification of intervertebral disc extrusion (T2-SAG: 92.7%, STIR-SAG: 94.5%, P = 0.752). Nevertheless, STIR-SAG accurately identified intervertebral disc extrusion in 66.7% of cases where the evaluation of T2-SAG in isolation had provided a false negative diagnosis. Additionally, one radiologist found that the parallel evaluation of paired T2-SAG and STIR-SAG series provided a significantly higher sensitivity than T2-SAG in isolation, during the identification of intervertebral disc extrusion (T2-SAG: 78.2%, paired T2-SAG, and STIR-SAG: 90.9%, P = 0.017). A similar nonsignificant trend was observed when the consensus of both radiologists was taken into consideration (T2-SAG: 92.7%, paired T2-SAG, and STIR-SAG = 97.3%, P = 0.392). We therefore conclude that STIR-SAG is capable of identifying intervertebral disc extrusion that is inconspicuous in T2-SAG, and that STIR-SAG should be considered a useful adjunctive sequence during preliminary sagittal screening for intervertebral disc extrusion in low-field magnetic resonance. © 2017 American College of Veterinary Radiology.

SnSAG5 is an alternative surface antigen of Sarcocystis neurona strains that is mutually exclusive to SnSAG1.

PubMed

Crowdus, Carolyn A; Marsh, Antoinette E; Saville, Willliam J; Lindsay, David S; Dubey, J P; Granstrom, David E; Howe, Daniel K

2008-11-25

Sarcocystis neurona is an obligate intracellular parasite that causes equine protozoal myeloencephalitis (EPM). Previous work has identified a gene family of paralogous surface antigens in S. neurona called SnSAGs. These surface proteins are immunogenic in their host animals, and are therefore candidate molecules for development of diagnostics and vaccines. However, SnSAG diversity exists in strains of S. neurona, including the absence of the major surface antigen gene SnSAG1. Instead, sequence for an alternative SnSAG has been revealed in two of the SnSAG1-deficient strains. Herein, we present data characterizing this new surface protein, which we have designated SnSAG5. The results indicated that the protein encoded by the SnSAG5 sequence is indeed a surface-associated molecule that has characteristics consistent with the other SAGs identified in S. neurona and related parasites. Importantly, Western blot analyses of a collection of S. neurona strains demonstrated that 6 of 13 parasite isolates express SnSAG5 as a dominant surface protein instead of SnSAG1. Conversely, SnSAG5 was not detected in SnSAG1-positive strains. One strain, which was isolated from the brain of a sea otter, did not express either SnSAG1 or SnSAG5. Genetic analysis with SnSAG5-specific primers confirmed the presence of the SnSAG5 gene in Western blot-positive strains, while also suggesting the presence of a novel SnSAG sequence in the SnSAG1-deficient, SnSAG5-deficient otter isolate. The findings provide further indication of S. neurona strain diversity, which has implications for diagnostic testing and development of vaccines against EPM as well as the population biology of Sarcocystis cycling in the opossum definitive host.

Optimal line drop compensation parameters under multi-operating conditions

NASA Astrophysics Data System (ADS)

Wan, Yuan; Li, Hang; Wang, Kai; He, Zhe

2017-01-01

Line Drop Compensation (LDC) is a main function of Reactive Current Compensation (RCC) which is developed to improve voltage stability. While LDC has benefit to voltage, it may deteriorate the small-disturbance rotor angle stability of power system. In present paper, an intelligent algorithm which is combined by Genetic Algorithm (GA) and Backpropagation Neural Network (BPNN) is proposed to optimize parameters of LDC. The objective function proposed in present paper takes consideration of voltage deviation and power system oscillation minimal damping ratio under multi-operating conditions. A simulation based on middle area of Jiangxi province power system is used to demonstrate the intelligent algorithm. The optimization result shows that coordinate optimized parameters can meet the multioperating conditions requirement and improve voltage stability as much as possible while guaranteeing enough damping ratio.

Divide and conquer: The Pseudomonas aeruginosa two-component hybrid SagS enables biofilm formation and recalcitrance of biofilm cells to antimicrobial agents via distinct regulatory circuits

PubMed Central

Petrova, Olga E.; Gupta, Kajal; Liao, Julie; Goodwine, James S.; Sauer, Karin

2017-01-01

The opportunistic pathogen Pseudomonas aeruginosa forms antimicrobial resistant biofilms through sequential steps requiring several two-component regulatory systems. The sensor-regulator hybrid SagS plays a central role in biofilm development by enabling the switch from the planktonic to the biofilm mode of growth, and by facilitating the transition of biofilm cells to a highly tolerant state. However, the mechanism by which SagS accomplishes both functions is unknown. SagS harbors a periplasmic sensory HmsP, and phosphorelay HisKA and Rec domains. We used SagS domain constructs and site-directed mutagenesis to elucidate how SagS performs its dual functions. We demonstrate that HisKA-Rec and the phospho-signaling between SagS and BfiS contribute to the switch to the biofilm mode of growth, but not to the tolerant state. Instead, expression of SagS domain constructs harboring HmsP rendered ΔsagS biofilm cells as recalcitrant to antimicrobial agents as wild-type biofilms, likely by restoring BrlR production and cellular c-di-GMP levels to wild-type levels. Restoration of biofilm tolerance by HmsP was independent of biofilm biomass accumulation, RsmA, RsmYZ, HptB, and BfiSR-downstream targets. Our findings thus suggest that SagS likely makes use of a “divide-and-conquer” mechanism to regulate its dual switch function, by activating two distinct regulatory networks via its individual domains. PMID:28263038

Asymmetric dee-voltage compensation of beam off-centering in the milan superconducting cyclotron

DOE Office of Scientific and Technical Information (OSTI.GOV)

Milinkovic, Lj.; Fabrici, E.; Ostojic, R.

1985-10-01

An analysis of the effects of orbit off-centering on the beam extraction in the Milan superconducting cyclotron is made, and the sensitivity of axial beam loss and radial phase space distortions to beam off-centering determined for various acceleration conditions. We conclude that the first field harmonic compensation of beam off-centering is ineffective in the region of the operating diagram where the Walkinshaw resonance precedes the ..nu.. /SUB r/ =1 resonance. Asymmetric dee-voltage compensation is considered in these cases, and the domain of validity of the method determined. A semi-empirical relation for dee-voltage distribution is deduced, and the extraction efficiency discussed.

The Yin and Yang of SagS: Distinct Residues in the HmsP Domain of SagS Independently Regulate Biofilm Formation and Biofilm Drug Tolerance

PubMed Central

Dingemans, Jozef; Poudyal, Bandita

2018-01-01

ABSTRACT The formation of inherently drug-tolerant biofilms by the opportunistic pathogen Pseudomonas aeruginosa requires the sensor-regulator hybrid SagS, with ΔsagS biofilms being unstructured and exhibiting increased antimicrobial susceptibility. Recent findings indicated SagS to function as a switch to control biofilm formation and drug tolerance independently. Moreover, findings suggested the periplasmic sensory HmsP domain of SagS is likely to be the control point in the regulation of biofilm formation and biofilm cells transitioning to a drug-tolerant state. We thus asked whether specific amino acid residues present in the HmsP domain contribute to the switch function of SagS. HmsP domain residues were therefore subjected to alanine replacement mutagenesis to identify substitutions that block the sensory function(s) of SagS, which is apparent by attached cells being unable to develop mature biofilms and/or prevent transition to an antimicrobial-resistant state. Mutant analyses revealed 32 residues that only contribute to blocking one sensory function. Moreover, amino acid residues affecting attachment and subsequent biofilm formation but not biofilm tolerance also impaired histidine kinase signaling via BfiS. In contrast, residues affecting biofilm drug tolerance but not attachment and subsequent biofilm formation negatively impacted BrlR transcription factor levels. Structure prediction suggested the two sets of residues affecting sensory functions are located in distinct areas that were previously described as being involved in ligand binding interactions. Taken together, these studies identify the molecular basis for the dual regulatory function of SagS. IMPORTANCE The membrane-bound sensory protein SagS plays a pivotal role in P. aeruginosa biofilm formation and biofilm cells gaining their heightened resistance to antimicrobial agents, with SagS being the control point at which both pathways diverge. Here, we demonstrate for the first time that the two distinct pathways leading to biofilm formation and biofilm drug tolerance are under the control of two sets of amino acid residues located within the HmsP sensory domain of SagS. The respective amino acids are likely part of ligand binding interaction sites. Thus, our findings have the potential not only to enable the manipulation of SagS function but also to enable research of biofilm drug tolerance in a manner independent of biofilm formation (and vice versa). Moreover, the manipulation of SagS function represents a promising target/avenue open for biofilm control. PMID:29848761

High-speed low-power voltage-programmed driving scheme for AMOLED displays

NASA Astrophysics Data System (ADS)

Xingheng, Xia; Weijing, Wu; Xiaofeng, Song; Guanming, Li; Lei, Zhou; Lirong, Zhang; Miao, Xu; Lei, Wang; Junbiao, Peng

2015-12-01

A new voltage-programmed driving scheme named the mixed parallel addressing scheme is presented for AMOLED displays, in which one compensation interval can be divided into the first compensation frame and the consequent N -1 post-compensation frames without periods of initialization and threshold voltage detection. The proposed driving scheme has the advantages of both high speed and low driving power due to the mixture of the pipeline technology and the threshold voltage one-time detection technology. Corresponding to the proposed driving scheme, we also propose a new voltage-programmed compensation pixel circuit, which consists of five TFTs and two capacitors (5T2C). In-Zn-O thin-film transistors (IZO TFTs) are used to build the proposed 5T2C pixel circuit. It is shown that the non-uniformity of the proposed pixel circuit is considerably reduced compared with that of the conventional 2T1C pixel circuit. The number of frames (N) preserved in the proposed driving scheme are measured and can be up to 35 with the variation of the OLED current remaining in an acceptable range. Moreover, the proposed voltage-programmed driving scheme can be more valuable for an AMOLED display with high resolution, and may also be applied to other compensation pixel circuits. Project supported by the State Key Development Program for Basic Research of China (No. 2015CB655000) the National Natural Science Foundation of China (Nos. 61204089, 61306099, 61036007, 51173049, U1301243), and the Fundamental Research Funds for the Central Universities (Nos. 2013ZZ0046, 2014ZZ0028).

Driving Method for Compensating Reliability Problem of Hydrogenated Amorphous Silicon Thin Film Transistors and Image Sticking Phenomenon in Active Matrix Organic Light-Emitting Diode Displays

NASA Astrophysics Data System (ADS)

Shin, Min-Seok; Jo, Yun-Rae; Kwon, Oh-Kyong

2011-03-01

In this paper, we propose a driving method for compensating the electrical instability of hydrogenated amorphous silicon (a-Si:H) thin film transistors (TFTs) and the luminance degradation of organic light-emitting diode (OLED) devices for large active matrix OLED (AMOLED) displays. The proposed driving method senses the electrical characteristics of a-Si:H TFTs and OLEDs using current integrators and compensates them by an external compensation method. Threshold voltage shift is controlled a using negative bias voltage. After applying the proposed driving method, the measured error of the maximum emission current ranges from -1.23 to +1.59 least significant bit (LSB) of a 10-bit gray scale under the threshold voltage shift ranging from -0.16 to 0.17 V.

Development of a 600 kJ HTS SMES

NASA Astrophysics Data System (ADS)

Seong, K. C.; Kim, H. J.; Kim, S. H.; Sim, K. D.; Sohn, M. H.; Lee, E. Y.; Park, S. J.; Hahn, S. Y.; Park, M. W.

2008-09-01

This paper describes an overview of development on a 600 kJ high-temperature superconducting magnetic energy storage (HTS SMES). Our final goal will be the commercialization of MJ class HTS SMES system for the increase of power quality within 5 years. Hence, for this purpose, we have developed the research and development in 3 years. The purpose of this research is to develop a pilot system, which can protect the sensitivity loads from a momentary power interruption or a voltage sag.

Antimicrobial Tolerance of Pseudomonas aeruginosa Biofilms Is Activated during an Early Developmental Stage and Requires the Two-Component Hybrid SagS

PubMed Central

Gupta, Kajal; Marques, Cláudia N. H.; Petrova, Olga E.

2013-01-01

A hallmark characteristic of biofilms is their extraordinary tolerance to antimicrobial agents. While multiple factors are thought to contribute to the high level of antimicrobial tolerance of biofilms, little is known about the timing of induction of biofilm tolerance. Here, we asked when over the course of their development do biofilms gain their tolerance to antimicrobial agents? We demonstrate that in Pseudomonas aeruginosa, biofilm tolerance is linked to biofilm development, with transition to the irreversible attachment stage regulated by the two-component hybrid SagS, marking the timing when biofilms switch to the high-level tolerance phenotype. Inactivation of sagS rendered biofilms but not planktonic cells more susceptible to tobramycin, norfloxacin, and hydrogen peroxide. Moreover, inactivation of sagS also eliminated the recalcitrance of biofilms to killing by bactericidal antimicrobial agents, a phenotype comparable to that observed upon inactivation of brlR, which encodes a MerR-like transcriptional regulator required for biofilm tolerance. Multicopy expression of brlR in a ΔsagS mutant restored biofilm resistance and recalcitrance to killing by bactericidal antibiotics to wild-type levels. In contrast, expression of sagS did not restore the susceptibility phenotype of ΔbrlR mutant biofilms to wild-type levels, indicating that BrlR functions downstream of SagS. Inactivation of sagS correlated with reduced BrlR levels in biofilms, with the produced BrlR being impaired in binding to the previously described BrlR-activated promoters of the two multidrug efflux pump operons mexAB-oprM and mexEF-oprN. Our findings demonstrate that biofilm tolerance is linked to early biofilm development and SagS, with SagS contributing indirectly to BrlR activation. PMID:23995639

Low-power low-voltage superior-order curvature corrected voltage reference

NASA Astrophysics Data System (ADS)

Popa, Cosmin

2010-06-01

A complementary metal oxide semiconductor (CMOS) voltage reference with a logarithmic curvature-correction will be presented. The first-order compensation is realised using an original offset voltage follower (OVF) block as a proportional to absolute temperature (PTAT) voltage generator, with the advantages of reducing the silicon area and of increasing accuracy by replacing matched resistors with matched transistors. The new logarithmic curvature-correction technique will be implemented using an asymmetric differential amplifier (ADA) block for compensating the logarithmic temperature dependent term from the first-order compensated voltage reference. In order to increase the circuit accuracy, an original temperature-dependent current generator will be designed for computing the exact type of the implemented curvature-correction. The relatively small complexity of the current squarer allows an important increasing of the circuit accuracy that could be achieved by increasing the current generator complexity. As a result of operating most of the MOS transistors in weak inversion, the original proposed voltage reference could be valuable for low-power applications. The circuit is implemented in 0.35 μm CMOS technology and consumes only 60μA for t = 25°C, being supplied at the minimal supply voltage V DD = 1.75V. The temperature coefficient of the reference voltage is 8.7 ppm/°C, while the line sensitivity is 0.75 mV/V for a supply voltage between 1.75 V and 7 V.

A read-in IC for infrared scene projectors with voltage drop compensation for improved uniformity of emitter current

NASA Astrophysics Data System (ADS)

Cho, Min Ji; Shin, Uisub; Lee, Hee Chul

2017-05-01

This paper proposes a read-in integrated circuit (RIIC) for infrared scene projectors, which compensates for the voltage drops in ground lines in order to improve the uniformity of the emitter current. A current output digital-to-analog converter is utilized to convert digital scene data into scene data currents. The unit cells in the array receive the scene data current and convert it into data voltage, which simultaneously self-adjusts to account for the voltage drop in the ground line in order to generate the desired emitter current independently of variations in the ground voltage. A 32 × 32 RIIC unit cell array was designed and fabricated using a 0.18-μm CMOS process. The experimental results demonstrate that the proposed RIIC can output a maximum emitter current of 150 μA and compensate for a voltage drop in the ground line of up to 500 mV under a 3.3-V supply. The uniformity of the emitter current is significantly improved compared to that of a conventional RIIC.

Characterization of Toxoplasma gondii SAG2 Expressed in Insect Cells by Recombinant Baculovirus and Evaluation of Its Diagnostic Potential in an Enzyme-Linked Immunosorbent Assay

PubMed Central

Huang, Xiaohong; Xuan, Xuenan; Suzuki, Hiroshi; Sugimoto, Chihiro; Nagasawa, Hideyuki; Fujisaki, Kozo; Mikami, Takeshi; Igarashi, Ikuo

2002-01-01

A baculovirus carrying the SAG2 gene of Toxoplasma gondii was constructed, and recombinant SAG2 protein (S-rSAG2) was expressed in insect cells. S-rSAG2 was recognized by sera from cats and pigs infected with T. gondii. Mice immunized with S-rSAG2 produced high titers of specific immunoglobulin G2a (IgG2a) and IgG1 antibodies. In an indirect fluorescent antibody test, all mouse antisera against S-rSAG2 reacted strongly to the natural parasites, but those against rSAG2 expressed in Escherichia coli (E-rSAG2) only showed very weak reaction, although no markedly difference was found in the reaction to denatured antigen, T. gondii lysate, in Western blot analysis. The results suggest that S-rSAG2 is better than E-rSAG2 in both antigenicity and immunogenicity. Enzyme-linked immunosorbent assay (ELISA) with S-rSAG2 could differentiate clearly between sera from 30 specific-pathogen-free cats and 4 experimentally infected cats. Serum samples from domestic cats in Japan were tested by the ELISA and compared with a latex agglutination test (LAT) and ELISA with E-rSAG2. Of 187 samples, all 35 LAT-positive sera had strong reactions to S-rSAG2 and E-rSAG2. Of the 152 LAT-negative sera, 18 were positive in the ELISA with S-rSAG2, whereas only 2 were positive in the ELISA with E-rSAG2. Although there were significant correlations among the three methods, the ELISA with S-rSAG2 was more sensitive than the others, which could be attributed to the fact that S-rSAG2 shares some common conformational structure with the native antigen. The results suggest that S-rSAG2 would be a useful reagent for the detection of T. gondii infection in cats. PMID:12414772

Lower-Order Compensation Chain Threshold-Reduction Technique for Multi-Stage Voltage Multipliers.

PubMed

Dell' Anna, Francesco; Dong, Tao; Li, Ping; Wen, Yumei; Azadmehr, Mehdi; Casu, Mario; Berg, Yngvar

2018-04-17

This paper presents a novel threshold-compensation technique for multi-stage voltage multipliers employed in low power applications such as passive and autonomous wireless sensing nodes (WSNs) powered by energy harvesters. The proposed threshold-reduction technique enables a topological design methodology which, through an optimum control of the trade-off among transistor conductivity and leakage losses, is aimed at maximizing the voltage conversion efficiency (VCE) for a given ac input signal and physical chip area occupation. The conducted simulations positively assert the validity of the proposed design methodology, emphasizing the exploitable design space yielded by the transistor connection scheme in the voltage multiplier chain. An experimental validation and comparison of threshold-compensation techniques was performed, adopting 2N5247 N-channel junction field effect transistors (JFETs) for the realization of the voltage multiplier prototypes. The attained measurements clearly support the effectiveness of the proposed threshold-reduction approach, which can significantly reduce the chip area occupation for a given target output performance and ac input signal.

Mathematical Modeling Analysis of Operation Strategy after External Transmission Line Series Compensation

NASA Astrophysics Data System (ADS)

Feng, Peilei; Xu, Tianqi; Liu, Xiaoxin; Jan, Lisheng; Dai, Xiaozhong; Cai, Pengcheng

2018-01-01

Nujiang power grid is at the end of the Yunnan power grid, which is the side of power supply. Due to the regional restrictions and the lag of economic development and other factors, the structure of the power grid in Nujiang is relatively weak, and the voltage of the regional power grid is more prominent. Based on analysis on voltage exceeding limits of Nujiang different power grid, combined with the operating characteristics of regional power grid and reactive power compensation measures, this paper proposes measures for adjustment of Nujiang grid voltage, and analyses the result of adjustment of voltage exceeding limits, which can effectively improve the voltage and power quality.

A new trivalent SnSAG surface antigen chimera for efficient detection of antibodies against Sarcocystis neurona and diagnosis of equine protozoal myeloencephalitis.

PubMed

Yeargan, Michelle; de Assis Rocha, Izabela; Morrow, Jennifer; Graves, Amy; Reed, Stephen M; Howe, Daniel K

2015-05-01

Enzyme-linked immunosorbent assays (ELISAs) based on the SnSAG surface antigens of Sarcocystis neurona provide reliable detection of infection by the parasite. Moreover, accurate serodiagnosis of equine protozoal myeloencephalitis (EPM) is achieved with the SnSAG ELISAs by measuring antibodies in serum and cerebrospinal fluid (CSF) to reveal active infection in the central nervous system. Two independent ELISAs based on recombinant (r)SnSAG2 or a chimeric fusion of SnSAG3 and SnSAG4 (rSnSAG4/3) are currently used together for EPM serodiagnosis to overcome varied antibody responses in different horses. To achieve reliable antibody detection with a single ELISA instead of 2 separate ELISAs, rSnSAG2 was fused with rSnSAG4/3 into a single trivalent protein, designated rSnSAG2/4/3. Paired serum and CSF from 163 horses were tested with all 3 ELISAs. When the consensus antibody titers obtained with the rSnSAG2 and rSnSAG4/3 ELISAs were compared to the single SAG2/4/3 ELISA titers, Spearman rank correlation coefficients of ρ = 0.74 and ρ = 0.90 were obtained for serum and CSF, respectively, indicating strong agreement between the tests. When the rSnSAG2 and rSnSAG4/3 consensus serum-to-CSF titer ratio was compared to the rSnSAG2/4/3 serum-to-CSF titer ratio, the Spearman correlation coefficient was ρ = 0.87, again signifying strong agreement. Importantly, comparing the diagnostic interpretation of the serum-to-CSF titer ratios yielded a Cohen kappa value of 0.77. These findings suggest that the single ELISA based on the trivalent rSnSAG2/4/3 will provide serologic and diagnostic results that are highly comparable to the consensus of the 2 independent ELISAs based on rSnSAG2 and rSnSAG4/3. © 2015 The Author(s).

Improved detection of equine antibodies against Sarcocystis neurona using polyvalent ELISAs based on the parasite SnSAG surface antigens.

PubMed

Yeargan, Michelle R; Howe, Daniel K

2011-02-28

Equine protozoal myeloencephalitis (EPM) is a common neurologic disease of horses that is caused by the apicomplexan pathogen Sarcocystis neurona. To help improve serologic diagnosis of S. neurona infection, we have modified existing enzyme-linked immunosorbent assays (ELISAs) based on the immunogenic parasite surface antigens SnSAG2, SnSAG3, and SnSAG4 to make the assays polyvalent, thereby circumventing difficulties associated with parasite antigenic variants and diversity in equine immune responses. Two approaches were utilized to achieve polyvalence: (1) mixtures of the individual recombinant SnSAGs (rSnSAGs) were included in single ELISAs; (2) a collection of unique SnSAG chimeras that fused protein domains from different SnSAG surface antigens into a single recombinant protein were generated for use in the ELISAs. These new assays were assessed using a defined sample set of equine sera and cerebrospinal fluids (CSFs) that had been characterized by Western blot and/or were from confirmed EPM horses. While all of the polyvalent ELISAs performed relatively well, the highest sensitivity and specificity (100%/100%) were achieved with assays containing the rSnSAG4/2 chimera (Domain 1 of SnSAG4 fused to SnSAG2) or using a mixture of rSnSAG3 and rSnSAG4. The rSnSAG4 antigen alone and the rSnSAG4/3 chimera (Domain 1 of SnSAG4 fused to Domain 2 of SnSAG3) exhibited the next best accuracy at 95.2% sensitivity and 100% specificity. Binding ratios and percent positivity (PP) ratios, determined by comparing the mean values for positive versus negative samples, showed that the most advantageous signal to noise ratios were provided by rSnSAG4 and the rSnSAG4/3 chimera. Collectively, our results imply that a polyvalent ELISA based on SnSAG4 and SnSAG3, whether as a cocktail of two proteins or as a single chimeric protein, can give optimal results in serologic testing of serum or CSF for the presence of antibodies against S. neurona. The use of polyvalent SnSAG ELISAs will enhance the reliability of serologic testing for S. neurona infection, which should lead to improved diagnosis of EPM. Copyright © 2010 Elsevier B.V. All rights reserved.

The SnSAG merozoite surface antigens of Sarcocystis neurona are expressed differentially during the bradyzoite and sporozoite life cycle stages.

PubMed

Gautam, A; Dubey, J P; Saville, W J; Howe, D K

2011-12-29

Sarcocystis neurona is a two-host coccidian parasite whose complex life cycle progresses through multiple developmental stages differing at morphological and molecular levels. The S. neurona merozoite surface is covered by multiple, related glycosylphosphatidylinositol-linked proteins, which are orthologous to the surface antigen (SAG)/SAG1-related sequence (SRS) gene family of Toxoplasma gondii. Expression of the SAG/SRS proteins in T. gondii and another related parasite Neospora caninum is life-cycle stage specific and seems necessary for parasite transmission and persistence of infection. In the present study, the expression of S. neurona merozoite surface antigens (SnSAGs) was evaluated in the sporozoite and bradyzoite stages. Western blot analysis was used to compare SnSAG expression in merozoites versus sporozoites, while immunocytochemistry was performed to examine expression of the SnSAGs in merozoites versus bradyzoites. These analyses revealed that SnSAG2, SnSAG3 and SnSAG4 are expressed in sporozoites, while SnSAG5 was appeared to be downregulated in this life cycle stage. In S. neurona bradyzoites, it was found that SnSAG2, SnSAG3, SnSAG4 and SnSAG5 were either absent or expression was greatly reduced. As shown for T. gondii, stage-specific expression of the SnSAGs may be important for the parasite to progress through its developmental stages and complete its life cycle successfully. Thus, it is possible that the SAG switching mechanism by these parasites could be exploited as a point of intervention. As well, the alterations in surface antigen expression during different life cycle stages may need to be considered when designing prospective approaches for protective vaccination. Copyright © 2011 Elsevier B.V. All rights reserved.

Series resistance compensation for whole-cell patch-clamp studies using a membrane state estimator

PubMed Central

Sherman, AJ; Shrier, A; Cooper, E

1999-01-01

Whole-cell patch-clamp techniques are widely used to measure membrane currents from isolated cells. While suitable for a broad range of ionic currents, the series resistance (R(s)) of the recording pipette limits the bandwidth of the whole-cell configuration, making it difficult to measure rapid ionic currents. To increase bandwidth, it is necessary to compensate for R(s). Most methods of R(s) compensation become unstable at high bandwidth, making them hard to use. We describe a novel method of R(s) compensation that overcomes the stability limitations of standard designs. This method uses a state estimator, implemented with analog computation, to compute the membrane potential, V(m), which is then used in a feedback loop to implement a voltage clamp; we refer to this as state estimator R(s) compensation. To demonstrate the utility of this approach, we built an amplifier incorporating state estimator R(s) compensation. In benchtop tests, our amplifier showed significantly higher bandwidths and improved stability when compared with a commercially available amplifier. We demonstrated that state estimator R(s) compensation works well in practice by recording voltage-gated Na(+) currents under voltage-clamp conditions from dissociated neonatal rat sympathetic neurons. We conclude that state estimator R(s) compensation should make it easier to measure large rapid ionic currents with whole-cell patch-clamp techniques. PMID:10545359

Sarcocystis neurona Merozoites Express a Family of Immunogenic Surface Antigens That Are Orthologues of the Toxoplasma gondii Surface Antigens (SAGs) and SAG-Related Sequences†

PubMed Central

Howe, Daniel K.; Gaji, Rajshekhar Y.; Mroz-Barrett, Meaghan; Gubbels, Marc-Jan; Striepen, Boris; Stamper, Shelby

2005-01-01

Sarcocystis neurona is a member of the Apicomplexa that causes myelitis and encephalitis in horses but normally cycles between the opossum and small mammals. Analysis of an S. neurona expressed sequence tag (EST) database revealed four paralogous proteins that exhibit clear homology to the family of surface antigens (SAGs) and SAG-related sequences of Toxoplasma gondii. The primary peptide sequences of the S. neurona proteins are consistent with the two-domain structure that has been described for the T. gondii SAGs, and each was predicted to have an amino-terminal signal peptide and a carboxyl-terminal glycolipid anchor addition site, suggesting surface localization. All four proteins were confirmed to be membrane associated and displayed on the surface of S. neurona merozoites. Due to their surface localization and homology to T. gondii surface antigens, these S. neurona proteins were designated SnSAG1, SnSAG2, SnSAG3, and SnSAG4. Consistent with their homology, the SnSAGs elicited a robust immune response in infected and immunized animals, and their conserved structure further suggests that the SnSAGs similarly serve as adhesins for attachment to host cells. Whether the S. neurona SAG family is as extensive as the T. gondii SAG family remains unresolved, but it is probable that additional SnSAGs will be revealed as more S. neurona ESTs are generated. The existence of an SnSAG family in S. neurona indicates that expression of multiple related surface antigens is not unique to the ubiquitous organism T. gondii. Instead, the SAG gene family is a common trait that presumably has an essential, conserved function(s). PMID:15664946

Sarcocystis neurona merozoites express a family of immunogenic surface antigens that are orthologues of the Toxoplasma gondii surface antigens (SAGs) and SAG-related sequences.

PubMed

Howe, Daniel K; Gaji, Rajshekhar Y; Mroz-Barrett, Meaghan; Gubbels, Marc-Jan; Striepen, Boris; Stamper, Shelby

2005-02-01

Sarcocystis neurona is a member of the Apicomplexa that causes myelitis and encephalitis in horses but normally cycles between the opossum and small mammals. Analysis of an S. neurona expressed sequence tag (EST) database revealed four paralogous proteins that exhibit clear homology to the family of surface antigens (SAGs) and SAG-related sequences of Toxoplasma gondii. The primary peptide sequences of the S. neurona proteins are consistent with the two-domain structure that has been described for the T. gondii SAGs, and each was predicted to have an amino-terminal signal peptide and a carboxyl-terminal glycolipid anchor addition site, suggesting surface localization. All four proteins were confirmed to be membrane associated and displayed on the surface of S. neurona merozoites. Due to their surface localization and homology to T. gondii surface antigens, these S. neurona proteins were designated SnSAG1, SnSAG2, SnSAG3, and SnSAG4. Consistent with their homology, the SnSAGs elicited a robust immune response in infected and immunized animals, and their conserved structure further suggests that the SnSAGs similarly serve as adhesins for attachment to host cells. Whether the S. neurona SAG family is as extensive as the T. gondii SAG family remains unresolved, but it is probable that additional SnSAGs will be revealed as more S. neurona ESTs are generated. The existence of an SnSAG family in S. neurona indicates that expression of multiple related surface antigens is not unique to the ubiquitous organism T. gondii. Instead, the SAG gene family is a common trait that presumably has an essential, conserved function(s).

A new curvature compensation technique for CMOS voltage reference using |VGS| and ΔVBE

NASA Astrophysics Data System (ADS)

Xuemin, Li; Mao, Ye; Gongyuan, Zhao; Yun, Zhang; Yiqiang, Zhao

2016-05-01

A new mixed curvature compensation technique for CMOS voltage reference is presented, which resorts to two sub-references with complementary temperature characteristics. The first sub-reference is the source-gate voltage |VGS|p of a PMOS transistor working in the saturated region. The second sub-reference is the weighted sum of gate-source voltages |VGS|n of NMOS transistors in the subthreshold region and the difference between two base-emitter voltages ΔVBE of bipolar junction transistors (BJTs). The voltage reference implemented utilizing the proposed curvature compensation technique exhibits a low temperature coefficient and occupies a small silicon area. The proposed technique was verified in 0.18 μm standard CMOS process technology. The performance of the circuit has been measured. The measured results show a temperature coefficient as low as 12.7 ppm/°C without trimming, over a temperature range from -40 to 120 °C, and the current consumption is 50 μA at room temperature. The measured power-supply rejection ratio (PSRR) is -31.2 dB @ 100 kHz. The circuit occupies an area of 0.045 mm2. Project supported by the National Natural Science Foundation of China (No. 61376032).

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.

SagE induces highly effective protective immunity against Streptococcus iniae mainly through an immunogenic domain in the extracellular region.

PubMed

Sun, Yun; Sun, Li; Xing, Ming-qing; Liu, Chun-sheng; Hu, Yong-hua

2013-11-12

Streptococcus iniae is a Gram-positive bacterium and a severe pathogen of a wide range of farmed fish. S. iniae possesses a virulence-associated streptolysin S cluster composed of several components, one of which is SagE. SagE a transmembrane protein with one major extracellular region named ECR. This study aimed to develop a SagE-based DNA candidate vaccine against streptococcosis and examine the immunoprotective mechanism of the vaccine. We constructed a DNA vaccine, pSagE, based on the sagE gene and examined its immunological property in a Japanese flounder (Paralichthys olivaceus) model. The results showed that at 7 days post-vaccination, expression of SagE at transcription and translation levels was detected in the tissues of the vaccinated fish. After challenge with S. iniae at one and two months post-vaccination, pSagE-vaccinated fish exhibited relative percent survival (RPS) of 95% and 88% respectively. Immunological analysis showed that (i) pSagE significantly upregulated the expression of a wide range of immune genes, (ii) pSagE induced the production of specific serum antibodies that bound whole-cell S. iniae, and (iii) treatment of S. iniae with pSagE-induced antibodies blocked bacterial invasion of host cells. To localize the immunoprotective domain of SagE, the ECR-expressing DNA vaccine pSagEECR was constructed. Immunization analysis showed that flounder vaccinated with pSagEECR exhibited a RPS of 68%, and that pSagEECR induced serum antibody production and immune gene expression in a manner similar to, though to lower magnitudes than, those induced by pSagE. We in this study developed a DNA vaccine, pSagE, which induces highly protective immunity against S. iniae. The protective effect of pSagE is probably due to its ability to elicit systemic immune response, in particular that of the humoral branch, which leads to production of specific serum antibodies that impair bacterial infection. These results add insights to the immunoprotective mechanism of fish DNA vaccine.

Molecular characterisation and the protective immunity evaluation of Eimeria maxima surface antigen gene.

PubMed

Liu, Tingqi; Huang, Jingwei; Li, Yanlin; Ehsan, Muhammad; Wang, Shuai; Zhou, Zhouyang; Song, Xiaokai; Yan, Ruofeng; Xu, Lixin; Li, Xiangrui

2018-05-30

Coccidiosis is recognised as a major parasitic disease in chickens. Eimeria maxima is considered as a highly immunoprotective species within the Eimeria spp. family that infects chickens. In the present research, the surface antigen gene of E. maxima (EmSAG) was cloned, and the ability of EmSAG to stimulate protection against E. maxima was evaluated. Prokaryotic and eukaryotic plasmids expressing EmSAG were constructed. The EmSAG transcription and expression in vivo was performed based on the RT-PCR and immunoblot analysis. The expression of EmSAG in sporozoites and merozoites was detected through immunofluorescence analyses. The immune protection was assessed based on challenge experiments. Flow cytometry assays were used to determine the T cell subpopulations. The serum antibody and cytokine levels were evaluated by ELISA. The open reading frame (ORF) of EmSAG gene contained 645 bp encoding 214 amino acid residues. The immunoblot and RT-PCR analyses indicated that the EmSAG gene were transcribed and expressed in vivo. The EmSAG proteins were expressed in sporozoite and merozoite stages of E. maxima by the immunofluorescence assay. Challenge experiments showed that both pVAX1-SAG and the recombinant EmSAG (rEmSAG) proteins were successful in alleviating jejunal lesions, decreasing loss of body weight and the oocyst ratio. Additionally, these experiments possessed anticoccidial indices (ACI) of more than 170. Higher percentages of CD4 + and CD8 + T cells were detected in both EmSAG-inoculated birds than those of the negative control groups (P < 0.05). The EmSAG-specific antibody concentrations of both the rEmSAG and pVAX1-EmSAG groups were much higher than those of the negative controls (P < 0.05). Higher concentrations of IL-4, IFN-γ, TGF-β1 and IL-17 were observed more in both the rEmSAG protein and pVAX1-SAG inoculated groups than those of negative controls (P < 0.05). Our findings suggest that EmSAG is capable of eliciting a moderate immune protection and could be used as an effective vaccine candidate against E. maxima.

Genetic Locus for Streptolysin S Production by Group A Streptococcus

PubMed Central

Nizet, Victor; Beall, Bernard; Bast, Darrin J.; Datta, Vivekananda; Kilburn, Laurie; Low, Donald E.; De Azavedo, Joyce C. S.

2000-01-01

Group A streptococcus (GAS) is an important human pathogen that causes pharyngitis and invasive infections, including necrotizing fasciitis. Streptolysin S (SLS) is the cytolytic factor that creates the zone of beta-hemolysis surrounding GAS colonies grown on blood agar. We recently reported the discovery of a potential genetic determinant involved in SLS production, sagA, encoding a small peptide of 53 amino acids (S. D. Betschel, S. M. Borgia, N. L. Barg, D. E. Low, and J. C. De Azavedo, Infect. Immun. 66:1671–1679, 1998). Using transposon mutagenesis, chromosomal walking steps, and data from the GAS genome sequencing project (www.genome.ou.edu/strep.html), we have now identified a contiguous nine-gene locus (sagA to sagI) involved in SLS production. The sag locus is conserved among GAS strains regardless of M protein type. Targeted plasmid integrational mutagenesis of each gene in the sag operon resulted in an SLS-negative phenotype. Targeted integrations (i) upstream of the sagA promoter and (ii) downstream of a terminator sequence after sagI did not affect SLS production, establishing the functional boundaries of the operon. A rho-independent terminator sequence between sagA and sagB appears to regulate the amount of sagA transcript produced versus transcript for the entire operon. Reintroduction of the nine-gene sag locus on a plasmid vector restored SLS activity to the nonhemolytic sagA knockout mutant. Finally, heterologous expression of the intact sag operon conferred the SLS beta-hemolytic phenotype to the nonhemolytic Lactococcus lactis. We conclude that gene products of the GAS sag operon are both necessary and sufficient for SLS production. Sequence homologies of sag operon gene products suggest that SLS is related to the bacteriocin family of microbial toxins. PMID:10858242

Self-assessment and goal-setting is associated with an improvement in interviewing skills.

PubMed

Hanley, Kathleen; Zabar, Sondra; Charap, Joseph; Nicholson, Joseph; Disney, Lindsey; Kalet, Adina; Gillespie, Colleen

2014-01-01

Purpose Describe the relationship between medical students' self-assessment and goal-setting (SAGS) skills and development of interviewing skills during the first-year doctoring course. Method 157 first-year medical students completed three two-case standardized patient (SP) interviews. After each of the first two, students viewed videotapes of their interview, completed a SAGS worksheet, and reviewed a selected tape segment in a seminar. SAGS was categorized into good and poor quality and interviewing skills were rated by trained raters. Results SAGS improved over time (37% good week 1 vs. 61% good week 10). Baseline SAGS and interviewing skills were not associated. Initial SAGS quality was associated with change in interviewing skills - those with poor-quality SAGS demonstrated a decrease and those with good-quality SAGS demonstrated an increase in scores by 17 weeks (ANOVA F=4.16, p=0.024). For students whose SAGS skills were good at both week 1 and 10, interviewing skills declined in weeks 1-10 and then increased significantly at week 17. For those whose SAGS remained 'poor' in weeks 1-10, interviewing skills declined in weeks 10-17. Conclusions In general, the quality of students' SAGS improved over time. Poor baseline SAGS skills and failure to improve were associated with a decrease in interviewing skills at 17 weeks. For students with better SAGS, interviewing skills increased at week 17. Improvement in SAGS skills was not associated with improved interviewing skills. Understanding structured self-assessment skills helps identify student characteristics that influence progressive mastery of communication skills and therefore may inform curriculum and remediation tailoring.

Self-assessment and goal-setting is associated with an improvement in interviewing skills.

PubMed

Hanley, Kathleen; Zabar, Sondra; Charap, Joseph; Nicholson, Joseph; Disney, Lindsey; Kalet, Adina; Gillespie, Colleen

2014-01-01

Describe the relationship between medical students' self-assessment and goal-setting (SAGS) skills and development of interviewing skills during the first-year doctoring course. 157 first-year medical students completed three two-case standardized patient (SP) interviews. After each of the first two, students viewed videotapes of their interview, completed a SAGS worksheet, and reviewed a selected tape segment in a seminar. SAGS was categorized into good and poor quality and interviewing skills were rated by trained raters. SAGS improved over time (37% good week 1 vs. 61% good week 10). Baseline SAGS and interviewing skills were not associated. Initial SAGS quality was associated with change in interviewing skills - those with poor-quality SAGS demonstrated a decrease and those with good-quality SAGS demonstrated an increase in scores by 17 weeks (ANOVA F=4.16, p=0.024). For students whose SAGS skills were good at both week 1 and 10, interviewing skills declined in weeks 1-10 and then increased significantly at week 17. For those whose SAGS remained 'poor' in weeks 1-10, interviewing skills declined in weeks 10-17. In general, the quality of students' SAGS improved over time. Poor baseline SAGS skills and failure to improve were associated with a decrease in interviewing skills at 17 weeks. For students with better SAGS, interviewing skills increased at week 17. Improvement in SAGS skills was not associated with improved interviewing skills. Understanding structured self-assessment skills helps identify student characteristics that influence progressive mastery of communication skills and therefore may inform curriculum and remediation tailoring.

Specification, Measurement, and Control of Electrical Switching Transients

NASA Technical Reports Server (NTRS)

Javor, K.

1999-01-01

There have been several instances of susceptibility to switching transients. The Space Shuttle Spacelab Remote Acquisition Unit (RAU-A standard interface between Spacelab payloads and the Shuttle communications system) will shut down if the input 28 Vdc bus drops below 22 volts for more than 80 gs. Although a MIL-STD-461 derivative CS06 requirement was levied on the RAU, it failed to find this susceptibility. A heavy payload on one aircraft sags the 28 volt bus below 20 volts for milliseconds. Dc-dc converters have an operating voltage. A typical 28 Vdc-to-5 Vdc converter operates within tolerance when input potential is between 17-40 Vdc, A hold-up capacitor can be used to extend the time this range is presented to the convener when the line potential sags or surges outside this range. The designer must know the range of normal transients in order to choose the correct value of hold-up. This report describes the phenomena of electrical power bus transients induced by the switching of loads both on and off the bus, and control thereof.

AC resistance measuring instrument

DOEpatents

Hof, P.J.

1983-10-04

An auto-ranging AC resistance measuring instrument for remote measurement of the resistance of an electrical device or circuit connected to the instrument includes a signal generator which generates an AC excitation signal for application to a load, including the device and the transmission line, a monitoring circuit which provides a digitally encoded signal representing the voltage across the load, and a microprocessor which operates under program control to provide an auto-ranging function by which range resistance is connected in circuit with the load to limit the load voltage to an acceptable range for the instrument, and an auto-compensating function by which compensating capacitance is connected in shunt with the range resistance to compensate for the effects of line capacitance. After the auto-ranging and auto-compensation functions are complete, the microprocessor calculates the resistance of the load from the selected range resistance, the excitation signal, and the load voltage signal, and displays of the measured resistance on a digital display of the instrument. 8 figs.

AC Resistance measuring instrument

DOEpatents

Hof, Peter J.

1983-01-01

An auto-ranging AC resistance measuring instrument for remote measurement of the resistance of an electrical device or circuit connected to the instrument includes a signal generator which generates an AC excitation signal for application to a load, including the device and the transmission line, a monitoring circuit which provides a digitally encoded signal representing the voltage across the load, and a microprocessor which operates under program control to provide an auto-ranging function by which range resistance is connected in circuit with the load to limit the load voltage to an acceptable range for the instrument, and an auto-compensating function by which compensating capacitance is connected in shunt with the range resistance to compensate for the effects of line capacitance. After the auto-ranging and auto-compensation functions are complete, the microprocessor calculates the resistance of the load from the selected range resistance, the excitation signal, and the load voltage signal, and displays of the measured resistance on a digital display of the instrument.

Self-assessment and goal-setting is associated with an improvement in interviewing skills

PubMed Central

Hanley, Kathleen; Zabar, Sondra; Charap, Joseph; Nicholson, Joseph; Disney, Lindsey; Kalet, Adina; Gillespie, Colleen

2014-01-01

Purpose Describe the relationship between medical students’ self-assessment and goal-setting (SAGS) skills and development of interviewing skills during the first-year doctoring course. Method 157 first-year medical students completed three two-case standardized patient (SP) interviews. After each of the first two, students viewed videotapes of their interview, completed a SAGS worksheet, and reviewed a selected tape segment in a seminar. SAGS was categorized into good and poor quality and interviewing skills were rated by trained raters. Results SAGS improved over time (37% good week 1 vs. 61% good week 10). Baseline SAGS and interviewing skills were not associated. Initial SAGS quality was associated with change in interviewing skills – those with poor-quality SAGS demonstrated a decrease and those with good-quality SAGS demonstrated an increase in scores by 17 weeks (ANOVA F=4.16, p=0.024). For students whose SAGS skills were good at both week 1 and 10, interviewing skills declined in weeks 1–10 and then increased significantly at week 17. For those whose SAGS remained ‘poor’ in weeks 1–10, interviewing skills declined in weeks 10–17. Conclusions In general, the quality of students’ SAGS improved over time. Poor baseline SAGS skills and failure to improve were associated with a decrease in interviewing skills at 17 weeks. For students with better SAGS, interviewing skills increased at week 17. Improvement in SAGS skills was not associated with improved interviewing skills. Understanding structured self-assessment skills helps identify student characteristics that influence progressive mastery of communication skills and therefore may inform curriculum and remediation tailoring. PMID:25059835

Effect of codon optimization and subcellular targeting on Toxoplasma gondii antigen SAG1 expression in tobacco leaves to use in subcutaneous and oral immunization in mice.

PubMed

Laguía-Becher, Melina; Martín, Valentina; Kraemer, Mauricio; Corigliano, Mariana; Yacono, María L; Goldman, Alejandra; Clemente, Marina

2010-07-15

Codon optimization and subcellular targeting were studied with the aim to increase the expression levels of the SAG178-322 antigen of Toxoplasma gondii in tobacco leaves. The expression of the tobacco-optimized and native versions of the SAG1 gene was explored by transient expression from the Agrobacterium tumefaciens binary expression vector, which allows targeting the recombinant protein to the endoplasmic reticulum (ER) and the apoplast. Finally, mice were subcutaneously and orally immunized with leaf extracts-SAG1 and the strategy of prime boost with rSAG1 expressed in Escherichia coli was used to optimize the oral immunization with leaf extracts-SAG1. Leaves agroinfiltrated with an unmodified SAG1 gene accumulated 5- to 10-fold more than leaves agroinfiltrated with a codon-optimized SAG1 gene. ER localization allowed the accumulation of higher levels of native SAG1. However, no significant differences were observed between the mRNA accumulations of the different versions of SAG1. Subcutaneous immunization with leaf extracts-SAG1 (SAG1) protected mice against an oral challenge with a non-lethal cyst dose, and this effect could be associated with the secretion of significant levels of IFN-gamma. The protection was increased when mice were ID boosted with rSAG1 (SAG1+boost). This group elicited a significant Th1 humoral and cellular immune response characterized by high levels of IFN-gamma. In an oral immunization assay, the SAG1+boost group showed a significantly lower brain cyst burden compared to the rest of the groups. Transient agroinfiltration was useful for the expression of all of the recombinant proteins tested. Our results support the usefulness of endoplasmic reticulum signal peptides in enhancing the production of recombinant proteins meant for use as vaccines. The results showed that this plant-produced protein has potential for use as vaccine and provides a potential means for protecting humans and animals against toxoplasmosis.

A robust low quiescent current power receiver for inductive power transmission in bio implants

NASA Astrophysics Data System (ADS)

Helalian, Hamid; Pasandi, Ghasem; Jafarabadi Ashtiani, Shahin

2017-05-01

In this paper, a robust low quiescent current complementary metal-oxide semiconductor (CMOS) power receiver for wireless power transmission is presented. This power receiver consists of three main parts including rectifier, switch capacitor DC-DC converter and low-dropout regulator (LDO) without output capacitor. The switch capacitor DC-DC converter has variable conversion ratios and synchronous controller that lets the DC-DC converter to switch among five different conversion ratios to prevent output voltage drop and LDO regulator efficiency reduction. For all ranges of output current (0-10 mA), the voltage regulator is compensated and is stable. Voltage regulator stabilisation does not need the off-chip capacitor. In addition, a novel adaptive biasing frequency compensation method for low dropout voltage regulator is proposed in this paper. This method provides essential minimum current for compensation and reduces the quiescent current more effectively. The power receiver was designed in a 180-nm industrial CMOS technology, and the voltage range of the input is from 0.8 to 2 V, while the voltage range of the output is from 1.2 to 1.75 V, with a maximum load current of 10 mA, the unregulated efficiency of 79.2%, and the regulated efficiency of 64.4%.

Voltage Drop Compensation Method for Active Matrix Organic Light Emitting Diode Displays

NASA Astrophysics Data System (ADS)

Choi, Sang-moo; Ryu, Do-hyung; Kim, Keum-nam; Choi, Jae-beom; Kim, Byung-hee; Berkeley, Brian

2011-03-01

In this paper, the conventional voltage drop compensation methods are reviewed and the novel design and driving scheme, the advanced power de-coupled (aPDC) driving method, is proposed to effectively compensate the voltage IR drop of active matrix light emitting diode (AMOLED) displays. The advanced PDC driving scheme can be applied to general AMOLED pixel circuits that have been developed with only minor modification or without requiring modification in pixel circuit. A 14-in. AMOLED panel with the aPDC driving scheme was fabricated. Long range uniformity (LRU) of the 14-in. AMOLED panel was improved from 43% without the aPDC driving scheme, to over 87% at the same brightness by using the scheme and the layout complexity of the panel with new design scheme is less than that of the panel with the conventional design scheme.

Wind Farm Stabilization by using DFIG with Current Controlled Voltage Source Converters Taking Grid Codes into Consideration

NASA Astrophysics Data System (ADS)

Okedu, Kenneth Eloghene; Muyeen, S. M.; Takahashi, Rion; Tamura, Junji

Recent wind farm grid codes require wind generators to ride through voltage sags, which means that normal power production should be re-initiated once the nominal grid voltage is recovered. However, fixed speed wind turbine generator system using induction generator (IG) has the stability problem similar to the step-out phenomenon of a synchronous generator. On the other hand, doubly fed induction generator (DFIG) can control its real and reactive powers independently while being operated in variable speed mode. This paper proposes a new control strategy using DFIGs for stabilizing a wind farm composed of DFIGs and IGs, without incorporating additional FACTS devices. A new current controlled voltage source converter (CC-VSC) scheme is proposed to control the converters of DFIG and the performance is verified by comparing the results with those of voltage controlled voltage source converter (VC-VSC) scheme. Another salient feature of this study is to reduce the number of proportionate integral (PI) controllers used in the rotor side converter without degrading dynamic and transient performances. Moreover, DC-link protection scheme during grid fault can be omitted in the proposed scheme which reduces overall cost of the system. Extensive simulation analyses by using PSCAD/EMTDC are carried out to clarify the effectiveness of the proposed CC-VSC based control scheme of DFIGs.

Diversity of Sarcocystis spp shed by opossums in Brazil inferred with phylogenetic analysis of DNA coding ITS1, cytochrome B, and surface antigens.

PubMed

Valadas, Samantha Y O B; da Silva, Juliana I G; Lopes, Estela Gallucci; Keid, Lara B; Zwarg, Ticiana; de Oliveira, Alice S; Sanches, Thaís C; Joppert, Adriana M; Pena, Hilda F J; Oliveira, Tricia M F S; Ferreira, Helena L; Soares, Rodrigo M

2016-05-01

Although few species of Sarcocystis are known to use marsupials of the genus Didelphis as definitive host, an extensive diversity of alleles of surface antigen genes (sag2, sag3, and sag4) has been described in samples of didelphid opossums in Brazil. In this work, we studied 25 samples of Sarcocystis derived from gastrointestinal tract of opossums of the genus Didelphis by accessing the variability of sag2, sag3, sag4, gene encoding cytochrome b (cytB) and first internal transcribed spacer (ITS1). Reference samples of Sarcocystis neurona (SN138) and Sarcocystis falcatula (SF1) maintained in cell culture were also analyzed. We found four allele variants of cytB, seven allele variants of ITS1, 10 allele variants of sag2, 13 allele variants of sag3, and 6 allele variants of sag4. None of the sporocyst-derived sequences obtained from Brazilian opossums revealed 100% identity to SN138 at cytB gene, nor to SN138 or SF1 at ITS1 locus. In addition, none of the sag alleles were found identical to either SF1 or SN138 homologous sequences, and a high number of new sag allele types were found other than those previously described in Brazil. Out of ten sag2 alleles, four are novel, while eight out of 13 sag3 alleles are novel and one out of six sag4 alleles is novel. Further studies are needed to clarify if such a vast repertoire of allele variants of Sarcocystis is the consequence of re-assortments driven by sexual exchange, in order to form individuals with highly diverse characteristics, such as pathogenicity, host spectrum, among others or if it only represents allele variants of different species with different biological traits. Copyright © 2016 Elsevier Inc. All rights reserved.

Strains of Sarcocystis neurona exhibit differences in their surface antigens, including the absence of the major surface antigen SnSAG1.

PubMed

Howe, Daniel K; Gaji, Rajshekhar Y; Marsh, Antoinette E; Patil, Bhagyashree A; Saville, William J; Lindsay, David S; Dubey, J P; Granstrom, David E

2008-05-01

A gene family of surface antigens is expressed by merozoites of Sarcocystis neurona, the primary cause of equine protozoal myeloencephalitis (EPM). These surface proteins, designated SnSAGs, are immunodominant and therefore excellent candidates for development of EPM diagnostics or vaccines. Prior work had identified an EPM isolate lacking the major surface antigen SnSAG1, thus suggesting there may be some diversity in the SnSAGs expressed by different S. neurona isolates. Therefore, a bioinformatic, molecular and immunological study was conducted to assess conservation of the SnSAGs. Examination of an expressed sequence tag (EST) database revealed several notable SnSAG polymorphisms. In particular, the EST information implied that the EPM strain SN4 lacked the major surface antigen SnSAG1. The absence of this surface antigen from the SN4 strain was confirmed by both Western blot and Southern blot. To evaluate SnSAG polymorphisms in the S. neurona population, 14 strains were examined by Western blots using monospecific polyclonal antibodies against the four described SnSAGs. The results of these analyses demonstrated that SnSAG2, SnSAG3, and SnSAG4 are present in all 14 S. neurona strains tested, although some variance in SnSAG4 was observed. Importantly, SnSAG1 was not detected in seven of the strains, which included isolates from four cases of EPM and a case of fatal meningoencephalitis in a sea otter. Genetic analyses by PCR using gene-specific primers confirmed the absence of the SnSAG1 locus in six of these seven strains. Collectively, the data indicated that there is heterogeneity in the surface antigen composition of different S. neurona isolates, which is an important consideration for development of serological tests and prospective vaccines for EPM. Furthermore, the diversity reported herein likely extends to other phenotypes, such as strain virulence, and may have implications for the phylogeny of the various Sarcocystis spp. that undergo sexual stages of their life cycle in opossums.

The fusion of Toxoplasma gondii SAG1 vaccine candidate to Leishmania infantum heat shock protein 83-kDa improves expression levels in tobacco chloroplasts.

PubMed

Albarracín, Romina M; Becher, Melina Laguía; Farran, Inmaculada; Sander, Valeria A; Corigliano, Mariana G; Yácono, María L; Pariani, Sebastián; López, Edwin Sánchez; Veramendi, Jon; Clemente, Marina

2015-05-01

Chloroplast transformation technology has emerged as an alternative platform offering many advantages over nuclear transformation. SAG1 is the main surface antigen of the intracellular parasite Toxoplasma gondii and a promising candidate to produce an anti-T. gondii vaccine. The aim of this study was to investigate the expression of SAG1 using chloroplast transformation technology in tobacco plants. In order to improve expression in transplastomic plants, we also expressed the 90-kDa heat shock protein of Leishmania infantum (LiHsp83) as a carrier for the SAG1 antigen. SAG1 protein accumulation in transplastomic plants was approximately 0.1-0.2 μg per gram of fresh weight (FW). Fusion of SAG1 to LiHsp83 significantly increased the level of SAG1 accumulation in tobacco chloroplasts (by up to 500-fold). We also evaluated the functionality of the chLiHsp83-SAG1. Three human seropositive samples reacted with SAG1 expressed in transplastomic chLiHsp83-SAG1 plants. Oral immunization with chLiHsp83-SAG1 elicited a significant reduction of the cyst burden that correlated with an increase of SAG1-specific antibodies. We propose the fusion of foreign proteins to LiHsp83 as a novel strategy to increase the expression level of the recombinant proteins using chloroplast transformation technology, thus addressing one of the current challenges for this approach in antigen protein production. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determining resistivity of a formation adjacent to a borehole having casing using multiple electrodes and with resistances being defined between the electrodes

DOEpatents

Vail, III, William B.

1996-01-01

Methods of operation of different types of multiple electrode apparatus vertically disposed in a cased well to measure information related to the resistivity of adjacent geological formations from inside the cased well. The multiple electrode apparatus have a minimum of three spaced apart voltage measurement electrodes that electrically engage the interior of the cased well. Measurement information is obtained related to current which is caused to flow from the cased well into the adjacent geological formation. First compensation information is obtained related to a first casing resistance between a first pair of the spaced apart voltage measurement electrodes. Second compensation information is obtained related to a second casing resistance between a second pair of the spaced apart voltage measurement electrodes. The measurement information, and first and second compensation information are used to determine a magnitude related to the adjacent formation resistivity.

Determining resistivity of a formation adjacent to a borehole having casing using multiple electrodes and with resistances being defined between the electrodes

DOEpatents

Vail, W.B. III

1996-10-29

Methods of operation are disclosed for different types of multiple electrode apparatus vertically disposed in a cased well to measure information related to the resistivity of adjacent geological formations from inside the cased well. The multiple electrode apparatus have a minimum of three spaced-apart voltage measurement electrodes that electrically engage the interior of the cased well. Measurement information is obtained related to current which is caused to flow from the cased well into the adjacent geological formation. First compensation information is obtained related to a first casing resistance between a first pair of the spaced-apart voltage measurement electrodes. Second compensation information is obtained related to a second casing resistance between a second pair of the spaced-apart voltage measurement electrodes. The measurement information, and first and second compensation information are used to determine a magnitude related to the adjacent formation resistivity. 13 figs.

A Fault Location Algorithm for Two-End Series-Compensated Double-Circuit Transmission Lines Using the Distributed Parameter Line Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kang, Ning; Gombos, Gergely; Mousavi, Mirrasoul J.

A new fault location algorithm for two-end series-compensated double-circuit transmission lines utilizing unsynchronized two-terminal current phasors and local voltage phasors is presented in this paper. The distributed parameter line model is adopted to take into account the shunt capacitance of the lines. The mutual coupling between the parallel lines in the zero-sequence network is also considered. The boundary conditions under different fault types are used to derive the fault location formulation. The developed algorithm directly uses the local voltage phasors on the line side of series compensation (SC) and metal oxide varistor (MOV). However, when potential transformers are not installedmore » on the line side of SC and MOVs for the local terminal, these measurements can be calculated from the local terminal bus voltage and currents by estimating the voltages across the SC and MOVs. MATLAB SimPowerSystems is used to generate cases under diverse fault conditions to evaluating accuracy. The simulation results show that the proposed algorithm is qualified for practical implementation.« less

Compensation for electrical converter nonlinearities

DOEpatents

Perisic, Milun; Ransom, Ray M; Kajouke, Lateef A

2013-11-19

Systems and methods are provided for delivering energy from an input interface to an output interface. An electrical system includes an input interface, an output interface, an energy conversion module between the input interface and the output interface, an inductive element between the input interface and the energy conversion module, and a control module. The control module determines a compensated duty cycle control value for operating the energy conversion module to produce a desired voltage at the output interface and operates the energy conversion module to deliver energy to the output interface with a duty cycle that is influenced by the compensated duty cycle control value. The compensated duty cycle control value is influenced by the current through the inductive element and accounts for voltage across the switching elements of the energy conversion module.

Compensated control loops for a 30-cm ion thruster

NASA Technical Reports Server (NTRS)

Robson, R. R.

1976-01-01

The vaporizer dynamic control characteristics of a 30-cm diameter mercury ion thruster were determined by operating the thruster in an open loop steady state mode and then introducing a small sinusoidal signal on the main, cathode, or neutralizer vaporizer current and observing the response of the beam current, discharge voltage, and neutralizer keeper voltage, respectively. This was done over a range of frequencies and operating conditions. From these data, Bode plots for gain and phase were made and mathematical models were obtained. The Bode plots and mathematical models were analyzed for stability and appropriate compensation networks determined. The compensated control loops were incorporated into a power processor and operated with a thruster. The time responses of the compensated loops to changes in set points and recovery from arc conditions are presented.

A combined compensation method for the output voltage of an insulated core transformer power supply

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, L.; Yang, J., E-mail: jyang@mail.hust.edu.cn; Liu, K. F.

2014-06-15

An insulated core transformer (ICT) power supply is an ideal high-voltage generator for irradiation accelerators with energy lower than 3 MeV. However, there is a significant problem that the structure of the segmented cores leads to an increase in the leakage flux and voltage differences between rectifier disks. A high level of consistency in the output of the disks helps to achieve a compact structure by improving the utilization of both the rectifier components and the insulation distances, and consequently increase the output voltage of the power supply. The output voltages of the disks which are far away from themore » primary coils need to be improved to reduce their inhomogeneity. In this study, by investigating and comparing the existing compensation methods, a new combined compensation method is proposed, which increases the turns on the secondary coils and employs parallel capacitors to improve the consistency of the disks, while covering the entire operating range of the power supply. This method turns out to be both feasible and effective during the development of an ICT power supply. The non-uniformity of the output voltages of the disks is less than 3.5% from no-load to full-load, and the power supply reaches an output specification of 350 kV/60 mA.« less

A New Low Temperature Polycrystalline Silicon Thin Film Transistor Pixel Circuit for Active Matrix Organic Light Emitting Diode

NASA Astrophysics Data System (ADS)

Ching-Lin Fan,; Yi-Yan Lin,; Jyu-Yu Chang,; Bo-Jhang Sun,; Yan-Wei Liu,

2010-06-01

This study presents one novel compensation pixel design and driving method for active matrix organic light-emitting diode (AMOLED) displays that use low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs) with a voltage feed-back method and the simulation results are proposed and verified by SPICE simulator. The measurement and simulation of LTPS TFT characteristics demonstrate the good fitting result. The proposed circuit consists of four TFTs and two capacitors with an additional signal line. The error rates of OLED anode voltage variation are below 0.3% under the threshold voltage deviation of driving TFT (Δ VTH = ± 0.33 V). The simulation results show that the pixel design can improve the display image non-uniformity by compensating the threshold voltage deviation of driving TFT and the degradation of OLED threshold voltage at the same time.

A New Low Temperature Polycrystalline Silicon Thin Film Transistor Pixel Circuit for Active Matrix Organic Light Emitting Diode

NASA Astrophysics Data System (ADS)

Fan, Ching-Lin; Lin, Yi-Yan; Chang, Jyu-Yu; Sun, Bo-Jhang; Liu, Yan-Wei

2010-06-01

This study presents one novel compensation pixel design and driving method for active matrix organic light-emitting diode (AMOLED) displays that use low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs) with a voltage feed-back method and the simulation results are proposed and verified by SPICE simulator. The measurement and simulation of LTPS TFT characteristics demonstrate the good fitting result. The proposed circuit consists of four TFTs and two capacitors with an additional signal line. The error rates of OLED anode voltage variation are below 0.3% under the threshold voltage deviation of driving TFT (ΔVTH = ±0.33 V). The simulation results show that the pixel design can improve the display image non-uniformity by compensating the threshold voltage deviation of driving TFT and the degradation of OLED threshold voltage at the same time.

Application of Static Var Compensator (SVC) With PI Controller for Grid Integration of Wind Farm Using Harmony Search

NASA Astrophysics Data System (ADS)

Keshta, H. E.; Ali, A. A.; Saied, E. M.; Bendary, F. M.

2016-10-01

Large-scale integration of wind turbine generators (WTGs) may have significant impacts on power system operation with respect to system frequency and bus voltages. This paper studies the effect of Static Var Compensator (SVC) connected to wind energy conversion system (WECS) on voltage profile and the power generated from the induction generator (IG) in wind farm. Also paper presents, a dynamic reactive power compensation using Static Var Compensator (SVC) at the a point of interconnection of wind farm while static compensation (Fixed Capacitor Bank) is unable to prevent voltage collapse. Moreover, this paper shows that using advanced optimization techniques based on artificial intelligence (AI) such as Harmony Search Algorithm (HS) and Self-Adaptive Global Harmony Search Algorithm (SGHS) instead of a Conventional Control Method to tune the parameters of PI controller for SVC and pitch angle. Also paper illustrates that the performance of the system with controllers based on AI is improved under different operating conditions. MATLAB/Simulink based simulation is utilized to demonstrate the application of SVC in wind farm integration. It is also carried out to investigate the enhancement in performance of the WECS achieved with a PI Controller tuned by Harmony Search Algorithm as compared to a Conventional Control Method.

Staphylococcal superantigens in colonization and disease

PubMed Central

Xu, Stacey X.; McCormick, John K.

2012-01-01

Superantigens (SAgs) are a family of potent immunostimulatory exotoxins known to be produced by only a few bacterial pathogens, including Staphylococcus aureus. More than 20 distinct SAgs have been characterized from different S. aureus strains and at least 80% of clinical strains harbor at least one SAg gene, although most strains encode many. SAgs have been classically associated with food poisoning and toxic shock syndrome (TSS), for which these toxins are the causative agent. TSS is a potentially fatal disease whereby SAg-mediated activation of T cells results in overproduction of cytokines and results in systemic inflammation and shock. Numerous studies have also shown a possible role for SAgs in other diseases such as Kawasaki disease (KD), atopic dermatitis (AD), and chronic rhinosinusitis (CRS). There is also now a rich understanding of the mechanisms of action of SAgs, as well as their structures and function. However, we have yet to discover what purpose SAgs play in the life cycle of S. aureus, and why such a wide array of these toxins exists. This review will focus on recent developments within the SAg field in terms of the molecular biology of these toxins and their role in both colonization and disease. PMID:22919643

Identification of the primary compensating defect level responsible for determining blocking voltage of vertical GaN power diodes

DOE PAGES

King, M. P.; Kaplar, R. J.; Dickerson, J. R.; ...

2016-10-31

Electrical performance and characterization of deep levels in vertical GaN P-i-N diodes grown on low threading dislocation density (~10 4 –10 6 cm –2) bulk GaN substrates are investigated. The lightly doped n drift region of these devices is observed to be highly compensated by several prominent deep levels detected using deep level optical spectroscopy at E c-2.13, 2.92, and 3.2 eV. A combination of steady-state photocapacitance and lighted capacitance-voltage profiling indicates the concentrations of these deep levels to be N t = 3 × 10 12, 2 × 10 15, and 5 × 10 14 cm –3, respectively. Themore » E c-2.92 eV level is observed to be the primary compensating defect in as-grown n-type metal-organic chemical vapor deposition GaN, indicating this level acts as a limiting factor for achieving controllably low doping. The device blocking voltage should increase if compensating defects reduce the free carrier concentration of the n drift region. Understanding the incorporation of as-grown and native defects in thick n-GaN is essential for enabling large V BD in the next-generation wide-bandgap power semiconductor devices. Furthermore, controlling the as-grown defects induced by epitaxial growth conditions is critical to achieve blocking voltage capability above 5 kV.« less

Resolving an anomaly in electron temperature measurement using double and triple Langmuir probes

NASA Astrophysics Data System (ADS)

Ghosh, Soumen; Barada, K. K.; Chattopadhyay, P. K.; Ghosh, J.; Bora, D.

2015-02-01

Langmuir probes with variants such as single, double and triple probes remain the most common method of electron temperature measurement in low-temperature laboratory plasmas. However, proper estimation of electron temperature mainly using triple probe configuration requires the proper choice of compensation factor (W). Determination of the compensating factor is not very straightforward as it depends heavily on plasma floating potential (Vf), electron temperature (Te), the type of gas used for plasma production and the bias voltage applied to probe pins, especially in cases where there are substantial variations in floating potential. In this paper we highlight the anomaly in electron temperature measurement using double and triple Langmuir probe techniques as well as the proper determination of the compensation factor (W) to overcome this anomaly. Experiments are carried out with helicon antenna producing inductive radiofrequency plasmas, where significant variation of floating potential along the axis enables a detailed study of deviations introduced in Te measurements using triple probes compared to double and single probes. It is observed that the bias voltage between the probe pins of the triple probes plays an important role in the accurate determination of the compensating factor (W) and should be in the range (5Vd2 < Vd3 < 10Vd2), where Vd2 and Vd3 are the voltage between floating probe pins 2 and 1 and the bias voltage, respectively.

Design and application of quadrature compensation patterns in bulk silicon micro-gyroscopes.

PubMed

Ni, Yunfang; Li, Hongsheng; Huang, Libin

2014-10-29

This paper focuses on the detailed design issues of a peculiar quadrature reduction method named system stiffness matrix diagonalization, whose key technology is the design and application of quadrature compensation patterns. For bulk silicon micro-gyroscopes, a complete design and application case was presented. The compensation principle was described first. In the mechanical design, four types of basic structure units were presented to obtain the basic compensation function. A novel layout design was proposed to eliminate the additional disturbing static forces and torques. Parameter optimization was carried out to maximize the available compensation capability in a limited layout area. Two types of voltage loading methods were presented. Their influences on the sense mode dynamics were analyzed. The proposed design was applied on a dual-mass silicon micro-gyroscope developed in our laboratory. The theoretical compensation capability of a quadrature equivalent angular rate no more than 412 °/s was designed. In experiments, an actual quadrature equivalent angular rate of 357 °/s was compensated successfully. The actual compensation voltages were a little larger than the theoretical ones. The correctness of the design and the theoretical analyses was verified. They can be commonly used in planar linear vibratory silicon micro-gyroscopes for quadrature compensation purpose.

ALSAT-2A power subsystem behavior during launch, early operation, and in-orbit test

NASA Astrophysics Data System (ADS)

Larbi, N.; Attaba, M.; Beaufume, E.

2012-09-01

In 2006, Algerian Space Agency (ASAL) decided to design and built two optical Earth observation satellites. The first one, ALSAT-2A, was integrated and tested as a training and cooperation program with EADS Astrium. The second satellite ALSAT-2B will be integrated by ASAL engineers in the Satellite Development Center (CDS) at Oran in Algeria. On 12th July 2010, Algeria has launched ALSAT-2A onboard an Indian rocket PSLV-C15 from the Sriharikota launch base, Chennaï. ALSAT-2A is the first Earth observation satellite of the AstroSat-100 family; the design is based on the Myriade platform and comprising the first flight model of the New Astrosat Observation Modular Instrument (NAOMI). This Instrument offers a 2.5m ground resolution for the PAN channel and a 10m ground resolution for four multi-spectral channels which provides high imaging quality. The operations are performed from ALSAT-2 ground segment located in Ouargla (Algeria) and after the test phase ALSAT-2A provides successful images. ALSAT-2A electrical power subsystem (EPS) is composed of a Solar Array Generator (SAG ), a Li-ion battery dedicated to power storage and energy source during eclipse or high consumption phases and a Power Conditioning and Distribution Unit (PCDU). This paper focuses primarily on ALSAT-2A electrical power subsystem behavior during Launch and Early OPeration (LEOP) as well as In Orbit Test (IOT). The telemetry data related to the SAG voltage, current and temperature will be analyzed in addition to battery temperature, voltage, charge and discharge current. These parameters will be studied in function of satellite power consumption.

A novel method of temperature compensation for piezoresistive microcantilever-based sensors.

PubMed

Han, Jianqiang; Wang, Xiaofei; Yan, Tianhong; Li, Yan; Song, Meixuan

2012-03-01

Microcantilever with integrated piezoresistor has been applied to in situ surface stress measurement in the field of biochemical sensors. It is well known that piezoresistive cantilever-based sensors are sensitive to ambient temperature changing due to highly temperature-dependent piezoresistive effect and mismatch in thermal expansion of composite materials. This paper proposes a novel method of temperature drift compensation for microcantilever-based sensors with a piezoresistive full Wheatstone bridge integrated at the clamped ends by subtracting the amplified output voltage of the reference cantilever from the output voltage of the sensing cantilever through a simple temperature compensating circuit. Experiments show that the temperature drift of microcantilever sensors can be significantly reduced by the method.

SU-E-I-51: Use of Blade Sequences in Cervical Spine MR Imaging for Eliminating Motion, Truncation and Flow Artifacts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mavroidis, P; Lavdas, E; Kostopoulos, S

Purpose: To assess the efficacy of the BLADE technique to eliminate motion, truncation, flow and other artifacts in Cervical Spine MRI compared to the conventional technique. To study the ability of the examined sequences to reduce the indetention and wrap artifacts, which have been reported in BLADE sagittal sequences. Methods: Forty consecutive subjects, who had been routinely scanned for cervical spine examination using four different image acquisition techniques, were analyzed. More specifically, the following pairs of sequences were compared: a) T2 TSE SAG vs. T2 TSE SAG BLADE and b) T2 TIRM SAG vs. T2 TIRM SAG BLADE. A quantitativemore » analysis was performed using the signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and relative contrast (ReCon) measures. A qualitative analysis was also performed by two radiologists, who graded seven image characteristics on a 5-point scale (0:non-visualization; 1:poor; 2:average; 3:good; 4:excellent). The observers also evaluated the presence of image artifacts (motion, truncation, flow, indentation). Results: Based on the findings of the quantitative analysis, the ReCON values of the CSF (cerebrospinal fluid)/SC (spinal cord) between TIRM SAG and TIRM SAG BLADE were found to present statistical significant differences (p<0.001). Regarding motion and truncation artifacts, the T2 TSE SAG BLADE was superior compared to the T2 TSE SAG and the T2 TIRM SAG BLADE was superior compared to the T2 TIRM SAG. Regarding flow artifacts, T2 TIRM SAG BLADE eliminated more artifacts compared to the T2 TIRM SAG. Conclusion: The use of BLADE sequences in cervical spine MR examinations appears to be capable of potentially eliminating motion, pulsatile flow and trancation artifacts. Furthermore, BLADE sequences are proposed to be used in the standard examination protocols based on the fact that a significantly improved image quality could be achieved.« less

ICESag37, a Novel Integrative and Conjugative Element Carrying Antimicrobial Resistance Genes and Potential Virulence Factors in Streptococcus agalactiae.

PubMed

Zhou, Kaixin; Xie, Lianyan; Han, Lizhong; Guo, Xiaokui; Wang, Yong; Sun, Jingyong

2017-01-01

ICE Sag37 , a novel integrative and conjugative element carrying multidrug resistance and potential virulence factors, was characterized in a clinical isolate of Streptococcus agalactiae . Two clinical strains of S. agalactiae , Sag37 and Sag158, were isolated from blood samples of new-borns with bacteremia. Sag37 was highly resistant to erythromycin and tetracycline, and susceptible to levofloxacin and penicillin, while Sag158 was resistant to tetracycline and levofloxacin, and susceptible to erythromycin. Transfer experiments were performed and selection was carried out with suitable antibiotic concentrations. Through mating experiments, the erythromycin resistance gene was found to be transferable from Sag37 to Sag158. Sma I-PFGE revealed a new Sma I fragment, confirming the transfer of the fragment containing the erythromycin resistance gene. Whole genome sequencing and sequence analysis revealed a mobile element, ICE Sag37 , which was characterized using several molecular methods and in silico analyses. ICE Sag37 was excised to generate a covalent circular intermediate, which was transferable to S. agalactiae . Inverse PCR was performed to detect the circular form. A serine family integrase mediated its chromosomal integration into rumA , which is a known hotspot for the integration of streptococcal ICEs. The integration site was confirmed using PCR. ICE Sag37 carried genes for resistance to multiple antibiotics, including erythromycin [ erm(B) ], tetracycline [ tet(O) ], and aminoglycosides [ aadE, aphA , and ant(6) ]. Potential virulence factors, including a two-component signal transduction system ( nisK/nisR ), were also observed in ICE Sag37 . S1-PFGE analysis ruled out the existence of plasmids. ICE Sag37 is the first ICE Sa2603 family-like element identified in S. agalactiae carrying both resistance and potential virulence determinants. It might act as a vehicle for the dissemination of multidrug resistance and pathogenicity among S. agalactiae .

VOLTAGE-CONTROLLED TRANSISTOR OSCILLATOR

DOEpatents

Scheele, P.F.

1958-09-16

This patent relates to transistor oscillators and in particular to those transistor oscillators whose frequencies vary according to controlling voltages. A principal feature of the disclosed transistor oscillator circuit resides in the temperature compensation of the frequency modulating stage by the use of a resistorthermistor network. The resistor-thermistor network components are selected to have the network resistance, which is in series with the modulator transistor emitter circuit, vary with temperature to compensate for variation in the parameters of the transistor due to temperature change.

Pixel structures to compensate nonuniform threshold voltage and mobility of polycrystalline silicon thin-film transistors using subthreshold current for large-size active matrix organic light-emitting diode displays

NASA Astrophysics Data System (ADS)

Na, Jun-Seok; Kwon, Oh-Kyong

2014-01-01

We propose pixel structures for large-size and high-resolution active matrix organic light-emitting diode (AMOLED) displays using a polycrystalline silicon (poly-Si) thin-film transistor (TFT) backplane. The proposed pixel structures compensate the variations of the threshold voltage and mobility of the driving TFT using the subthreshold current. The simulated results show that the emission current error of the proposed pixel structure B ranges from -2.25 to 2.02 least significant bit (LSB) when the variations of the threshold voltage and mobility of the driving TFT are ±0.5 V and ±10%, respectively.

Plastic Optical Fibre Sensor for Spine Bending Monitoring with Power Fluctuation Compensation

PubMed Central

Zawawi, Mohd Anwar; O'Keeffe, Sinead; Lewis, Elfed

2013-01-01

This paper presents the implementation of power fluctuation compensation for an intensity-based optical fibre bending sensor aimed at monitoring human spine bending in a clinical environment. To compensate for the light intensity changes from the sensor light source, a reference signal was provided via the light reflection from an aluminum foil surface fixed at a certain distance from the source fibre end tips. From the results, it was found that the investigated sensor compensation technique was capable of achieving a 2° resolution for a bending angle working range between 0° and 20°. The study also suggested that the output voltage ratio has a 0.55% diversion due to input voltage variation between 2.9 V and 3.4 V and a 0.25% output drift for a 2 h measurement. With the achieved sensor properties, human spine monitoring in a clinical environment can potentially be implemented using this approach with power fluctuation compensation. PMID:24233073

Publications - GMC 164 | Alaska Division of Geological & Geophysical

Science.gov Websites

Staines St. 10-09-23, Nora Fed #1, Sag Delta 33-12-16, Sag Delta #1, Kavik #1, BF-47 #1, OCS Y-0804-1 , Nora Fed #1, Sag Delta 33-12-16, Sag Delta #1, Kavik #1, BF-47 #1, OCS Y-0804-1 (Orion #1), OCS Y-0334

Application of active electrode compensation to perform continuous voltage-clamp recordings with sharp microelectrodes.

PubMed

Gómez-González, J F; Destexhe, A; Bal, T

2014-10-01

Electrophysiological recordings of single neurons in brain tissues are very common in neuroscience. Glass microelectrodes filled with an electrolyte are used to impale the cell membrane in order to record the membrane potential or to inject current. Their high resistance induces a high voltage drop when passing current and it is essential to correct the voltage measurements. In particular, for voltage clamping, the traditional alternatives are two-electrode voltage-clamp technique or discontinuous single electrode voltage-clamp (dSEVC). Nevertheless, it is generally difficult to impale two electrodes in a same neuron and the switching frequency is limited to low frequencies in the case of dSEVC. We present a novel fully computer-implemented alternative to perform continuous voltage-clamp recordings with a single sharp-electrode. To reach such voltage-clamp recordings, we combine an active electrode compensation algorithm (AEC) with a digital controller (AECVC). We applied two types of control-systems: a linear controller (proportional plus integrative controller) and a model-based controller (optimal control). We compared the performance of the two methods to dSEVC using a dynamic model cell and experiments in brain slices. The AECVC method provides an entirely digital method to perform continuous recording and smooth switching between voltage-clamp, current clamp or dynamic-clamp configurations without introducing artifacts.

High Power Laser Beam Welding of Thick-walled Ferromagnetic Steels with Electromagnetic Weld Pool Support

NASA Astrophysics Data System (ADS)

Fritzsche, André; Avilov, Vjaceslav; Gumenyuk, Andrey; Hilgenberg, Kai; Rethmeier, Michael

The development of modern high power laser systems allows single pass welding of thick-walled components with minimal distortion. Besides the high demands on the joint preparation, the hydrostatic pressure in the melt pool increases with higher plate thicknesses. Reaching or exceeding the Laplace pressure, drop-out or melt sagging are caused. A contactless electromagnetic weld support system was used for laser beam welding of thick ferromagnetic steel plates compensating these effects. An oscillating magnetic field induces eddy currents in the weld pool which generate Lorentz forces counteracting the gravity forces. Hysteresis effects of ferromagnetic steels are considered as well as the loss of magnetization in zones exceeding the Curie temperature. These phenomena reduce the effective Lorentz forces within the weld pool. The successful compensation of the hydrostatic pressure was demonstrated on up to 20 mm thick plates of duplex and mild steel by a variation of the electromagnetic power level and the oscillation frequency.

Compensated gain control circuit for buck regulator command charge circuit

DOEpatents

Barrett, David M.

1996-01-01

A buck regulator command charge circuit includes a compensated-gain control signal for compensating for changes in the component values in order to achieve optimal voltage regulation. The compensated-gain control circuit includes an automatic-gain control circuit for generating a variable-gain control signal. The automatic-gain control circuit is formed of a precision rectifier circuit, a filter network, an error amplifier, and an integrator circuit.

Compensated gain control circuit for buck regulator command charge circuit

DOEpatents

Barrett, D.M.

1996-11-05

A buck regulator command charge circuit includes a compensated-gain control signal for compensating for changes in the component values in order to achieve optimal voltage regulation. The compensated-gain control circuit includes an automatic-gain control circuit for generating a variable-gain control signal. The automatic-gain control circuit is formed of a precision rectifier circuit, a filter network, an error amplifier, and an integrator circuit. 5 figs.

Compensation of PVT Variations in ToF Imagers with In-Pixel TDC

PubMed Central

Vornicu, Ion; Carmona-Galán, Ricardo; Rodríguez-Vázquez, Ángel

2017-01-01

The design of a direct time-of-flight complementary metal-oxide-semiconductor (CMOS) image sensor (dToF-CIS) based on a single-photon avalanche-diode (SPAD) array with an in-pixel time-to-digital converter (TDC) must contemplate system-level aspects that affect its overall performance. This paper provides a detailed analysis of the impact of process parameters, voltage supply, and temperature (PVT) variations on the time bin of the TDC array. Moreover, the design and characterization of a global compensation loop is presented. It is based on a phase locked loop (PLL) that is integrated on-chip. The main building block of the PLL is a voltage-controlled ring-oscillator (VCRO) that is identical to the ones employed for the in-pixel TDCs. The reference voltage that drives the master VCRO is distributed to the voltage control inputs of the slave VCROs such that their multiphase outputs become invariant to PVT changes. These outputs act as time interpolators for the TDCs. Therefore the compensation scheme prevents the time bin of the TDCs from drifting over time due to the aforementioned factors. Moreover, the same scheme is used to program different time resolutions of the direct time-of-flight (ToF) imager aimed at 3D ranging or depth map imaging. Experimental results that validate the analysis are provided as well. The compensation loop proves to be remarkably effective. The spreading of the TDCs time bin is lowered from: (i) 20% down to 2.4% while the temperature ranges from 0 °C to 100 °C; (ii) 27% down to 0.27%, when the voltage supply changes within ±10% of the nominal value; (iii) 5.2 ps to 2 ps standard deviation over 30 sample chips, due to process parameters’ variation. PMID:28486405

Compensation of PVT Variations in ToF Imagers with In-Pixel TDC.

PubMed

Vornicu, Ion; Carmona-Galán, Ricardo; Rodríguez-Vázquez, Ángel

2017-05-09

The design of a direct time-of-flight complementary metal-oxide-semiconductor (CMOS) image sensor (dToF-CIS) based on a single-photon avalanche-diode (SPAD) array with an in-pixel time-to-digital converter (TDC) must contemplate system-level aspects that affect its overall performance. This paper provides a detailed analysis of the impact of process parameters, voltage supply, and temperature (PVT) variations on the time bin of the TDC array. Moreover, the design and characterization of a global compensation loop is presented. It is based on a phase locked loop (PLL) that is integrated on-chip. The main building block of the PLL is a voltage-controlled ring-oscillator (VCRO) that is identical to the ones employed for the in-pixel TDCs. The reference voltage that drives the master VCRO is distributed to the voltage control inputs of the slave VCROs such that their multiphase outputs become invariant to PVT changes. These outputs act as time interpolators for the TDCs. Therefore the compensation scheme prevents the time bin of the TDCs from drifting over time due to the aforementioned factors. Moreover, the same scheme is used to program different time resolutions of the direct time-of-flight (ToF) imager aimed at 3D ranging or depth map imaging. Experimental results that validate the analysis are provided as well. The compensation loop proves to be remarkably effective. The spreading of the TDCs time bin is lowered from: (i) 20% down to 2.4% while the temperature ranges from 0 °C to 100 °C; (ii) 27% down to 0.27%, when the voltage supply changes within ±10% of the nominal value; (iii) 5.2 ps to 2 ps standard deviation over 30 sample chips, due to process parameters' variation.

A morphometric assessment and classification of coral reef spur and groove morphology

NASA Astrophysics Data System (ADS)

Duce, S.; Vila-Concejo, A.; Hamylton, S. M.; Webster, J. M.; Bruce, E.; Beaman, R. J.

2016-07-01

Spurs and grooves (SaGs) are a common and important feature of coral reef fore slopes worldwide. However, they are difficult to access and hence their morphodynamics and formation are poorly understood. We use remote sensing, with extensive ground truthing, to measure SaG morphometrics and environmental factors at 11,430 grooves across 17 reefs in the southern Great Barrier Reef, Australia. We revealed strong positive correlations between groove length, orientation and wave exposure with longer, more closely-spaced grooves oriented easterly reflecting the dominant swell regime. Wave exposure was found to be the most important factor controlling SaG distribution and morphology. Gradient of the upper reef slope was also an important limiting factor, with SaGs less likely to develop in steeply sloping (> 5°) areas. We used a subset of the morphometric data (11 reefs) to statistically define four classes of SaG. This classification scheme was tested on the remaining six reefs. SaGs in the four classes differ in morphology, groove substrate and coral cover. These differences provide insights into SaG formation mechanisms with implications to reef platform growth and evolution. We hypothesize SaG formation is dominated by coral growth processes at two classes and erosion processes at one class. A fourth class may represent relic features formed earlier in the Holocene transgression. The classes are comparable with SaGs elsewhere, suggesting the classification could be applied globally with the addition of new classes if necessary. While further research is required, we show remotely sensed SaG morphometrics can provide useful insights into reef platform evolution.

Voltage regulation in linear induction accelerators

DOEpatents

Parsons, William M.

1992-01-01

Improvement in voltage regulation in a Linear Induction Accelerator wherein a varistor, such as a metal oxide varistor, is placed in parallel with the beam accelerating cavity and the magnetic core. The non-linear properties of the varistor result in a more stable voltage across the beam accelerating cavity than with a conventional compensating resistance.

A new very high voltage semiconductor switch

NASA Technical Reports Server (NTRS)

Sundberg, G. R.

1985-01-01

A new family of semiconductor switches using double injection techniques and compensated deep impurities is described. They have the potential to raise switching voltages a factor of 10 higher (up to 100 kV) than p-n junction devices while exhibiting extremely low (or zero) forward voltage. Several potential power switching applications are indicated.

Solutions for transients in arbitrarily branching cables: III. Voltage clamp problems.

PubMed

Major, G

1993-07-01

Branched cable voltage recording and voltage clamp analytical solutions derived in two previous papers are used to explore practical issues concerning voltage clamp. Single exponentials can be fitted reasonably well to the decay phase of clamped synaptic currents, although they contain many underlying components. The effective time constant depends on the fit interval. The smoothing effects on synaptic clamp currents of dendritic cables and series resistance are explored with a single cylinder + soma model, for inputs with different time courses. "Soma" and "cable" charging currents cannot be separated easily when the soma is much smaller than the dendrites. Subtractive soma capacitance compensation and series resistance compensation are discussed. In a hippocampal CA1 pyramidal neurone model, voltage control at most dendritic sites is extremely poor. Parameter dependencies are illustrated. The effects of series resistance compound those of dendritic cables and depend on the "effective capacitance" of the cell. Plausible combinations of parameters can cause order-of-magnitude distortions to clamp current waveform measures of simulated Schaeffer collateral inputs. These voltage clamp problems are unlikely to be solved by the use of switch clamp methods.

Performance Analysis of a Static Synchronous Compensator (STATCOM)

NASA Astrophysics Data System (ADS)

Kambey, M. M.; Ticoh, J. D.

2018-02-01

Reactive power and voltage are some of the problems in electric power supply and A Gate Turn Off (GTO) Static Synchronous Compensator (STATCOM) is one of the type of FACTS with shunt which can supply variable reactive power and regulate the voltage of the bus where it is connected. This study only discuss about the performance characteristic of the three phase six-pulse STATCOM by analysing the current wave flowing through DC Capacitor which depend on switching current and capacitor voltage wave. Simulation methods used in this research is started with a mathematical analysis of the ac current, dc voltage and current equations that pass STATCOM from a literature. The result shows the presence of the capacitor voltage ripple also alters the ac current waveform, even though the errors to be not very significant and the constraint of the symmetry circuit is valid if the source voltages have no zero sequence components and the impedances in all the three phases are identical. There for to improve STATCOM performance it is necessary to use multi-pulse 12, 24, 36, 48 or more, and/or with a multilevel converter.

A 2.87 ppm/°C 65 nm CMOS bandgap reference with nonlinearity compensation

NASA Astrophysics Data System (ADS)

Xingyuan, Tong; Zhangming, Zhu; Yintang, Yang

2011-09-01

Based on the review and analysis of two recently reported low temperature coefficient (TC) bandgap voltage references (BGRs), a new temperature compensation technique is presented. With the double-end piecewise nonlinearity correction method, the logarithm cancellation technique and the mixed-mode output topology, a BGR with high-temperature stability is realised based on 65 nm CMOS low-leakage process. The post-simulation results using Spectre show that this BGR produces an output voltage of about 953 mV with 2.5 V supply voltage, and the output voltage varies by only 0.16 mV from -40°C to 125°C. This low TC BGR has been used in a 65 nm CMOS touch screen controller, and the measurement shows that the output voltage of this BGR is about 949 mV varying by 0.44 mV from -40°C to 125°C. The TC of this BGR is about 2.87 ppm/°C, meeting the requirement of high-precision SoC application.

High-energy non-rechargeable batteries and their applications

NASA Astrophysics Data System (ADS)

Higgins, Robert; Kruger, Ken

1990-04-01

Many of the more recently developed high energy battery systems employ Li anodes, which are capable of energy densities of 700 W h/kg and shelf power-losses of less than 3 percent/yr. It has been noted, however, that some Li-based systems exhibit 'voltage sag' during storage and pose some safety problems in cases of inadvertent abuse. The two highest energy-output yielding of the current Li systems, namely Li/CF(x) spiral cells and Li/thionyl chloride liquid cathode cells, are presented and compared with a Zn/AgO electrochemical (aqueous) battery system which, although of older design, is still capable of substantial energy densities.

Regulation of the Output Voltage of an Inverter in Case of Load Variation

NASA Astrophysics Data System (ADS)

Diouri, Omar; Errahimi, Fatima; Es-Sbai, Najia

2018-05-01

In a DC/AC photovoltaic application, the stability of the output voltage of the inverter plays a very important role in the electrical systems. Such a photovoltaic system is constituted by an inverter, which makes it possible to convert the continuous energy to the alternative energy used in systems which operate under a voltage of 230V. The output of this inverter can be connected to a single load or more, at which time a second load is added in parallel with the first load. In this case, it proves a voltage drop at the output of the inverter. This problem influences the proper functioning of the electrical loads. Therefore, our contribution is to give a solution to this by compensating this voltage drop using a boost converter at the input of the inverter. This boost converter will play the role of the compensator that will provide the necessary voltage to the inverter in order to increase the voltage across the loads. But the use of this boost without controlling it is not enough because it generates a voltage that depends on the duty cycle of the control signal. To stabilize the output voltage of the inverter, we used a Proportional, Integral, and Derivative control (PID), which makes it possible to generate the necessary control signal for the voltage boost in order to have a good regulation of the output voltage of the inverter. Finally, we have solved the problem of the voltage drop even though there is loads variation.

Sagging Skin

MedlinePlus

... for Varicose Veins Sclerotherapy for Varicose Veins Back Hair Transplants Laser Treatments for Pre-Cancerous ... Skin Sagging skin in the lower face and neck is a natural part of the aging process. Why treat sagging ...

Method for passively compensating for temperature coefficient of gain in silicon photomultipliers and similar devices

DOEpatents

McKisson, John E.; Barbosa, Fernando

2015-09-01

A method for designing a completely passive bias compensation circuit to stabilize the gain of multiple pixel avalanche photo detector devices. The method includes determining circuitry design and component values to achieve a desired precision of gain stability. The method can be used with any temperature sensitive device with a nominally linear coefficient of voltage dependent parameter that must be stabilized. The circuitry design includes a negative temperature coefficient resistor in thermal contact with the photomultiplier device to provide a varying resistance and a second fixed resistor to form a voltage divider that can be chosen to set the desired slope and intercept for the characteristic with a specific voltage source value. The addition of a third resistor to the divider network provides a solution set for a set of SiPM devices that requires only a single stabilized voltage source value.

An ABA-regulated and Golgi-localized protein phosphatase controls water loss during leaf senescence in Arabidopsis.

PubMed

Zhang, Kewei; Xia, Xiuying; Zhang, Yanyan; Gan, Su-Sheng

2012-02-01

It is known that a senescing leaf loses water faster than a non-senescing leaf and that ABA has an important role in promoting leaf senescence. However, questions such as why water loss is faster, how water loss is regulated, and how ABA functions in leaf senescence are not well understood. Here we report on the identification and functional analysis of a leaf senescence associated gene called SAG113. The RNA blot and GUS reporter analyses all show that SAG113 is expressed in senescing leaves and is induced by ABA in Arabidopsis. The SAG113 expression levels are significantly reduced in aba2 and abi4 mutants. A GFP fusion protein analysis revealed that SAG113 protein is localized in the Golgi apparatus. SAG113 encodes a protein phosphatase that belongs to the PP2C family and is able to functionally complement a yeast PP2C-deficient mutant TM126 (ptc1Δ). Leaf senescence is delayed in the SAG113 knockout mutant compared with that in the wild type, stomatal movement in the senescing leaves of SAG113 knockouts is more sensitive to ABA than that of the wild type, and the rate of water loss in senescing leaves of SAG113 knockouts is significantly reduced. In contrast, inducible over-expression of SAG113 results in a lower sensitivity of stomatal movement to ABA treatment, more rapid water loss, and precocious leaf senescence. No other aspects of growth and development, including seed germination, were observed. These findings suggest that SAG113, a negative regulator of ABA signal transduction, is specifically involved in the control of water loss during leaf senescence. © 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd.

Compatibilization of acrylonitrile-butadiene-styrene terpolymer/poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate) blend: effect on morphology, interface, mechanical properties and hydrophilicity

NASA Astrophysics Data System (ADS)

Chen, Tingting; Zhang, Jun

2018-04-01

The compatibilization of acrylonitrile-butadiene-styrene terpolymer (ABS) and poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate) (PETG) blends was first investigated. Styrene-acrylonitrile-glycidyl methacrylate terpolymer (SAG) and ABS grafted with maleic anhydride (ABS-g-MAH) were selected as reactive compatibilizers for the ABS/PETG blends. The compatibilization effect was assessed by scanning electron microscope (SEM), differential scanning calorimetry (DSC) and mechanical properties. And the effect of compatibilizers on the hydrophilicity of the blends was evaluated as well. SEM observation and DSC analysis confirmed that both SAG and ABS-g-MAH compatibilizers could improve the compatibility between ABS and PETG, leading to an improvement in toughness of the blend. The possible cause for the improvement of compatibility was the reaction between compatibilizers and PETG, which could in situ turn out compatibilizers that acted as interfacial agents to enhance the interfacial interaction in the blend. Especially, the addition of SAG significantly decreased the dispersion phase size and the interface voids almost disappeared. Since the in situ reactions between the epoxy groups of SAG and the end groups (sbnd COOH or sbnd OH) of PETG generated PETG-co-SAG copolymer at the blend interface, and the cross-linking reactions proposed to take place between SAG and the PETG-co-SAG copolymer, acting as compatibilizer, could significantly increase the interfacial interaction. The addition of SAG also enhanced the stiffness of the blends. Moreover, the addition of SAG made the blend more hydrophilic, whereas the addition of ABS-g-MAH made the blend more hydrophobic. Therefore, SAG was a good compatibilizer for the ABS/PETG blends and could simultaneously provide the blends with toughening, stiffening and hydrophilic effects.

Intercellular Transfer of a Soluble Viral Superantigen

PubMed Central

Reilly, Melissa; Mix, Denise; Reilly, Andrew A.; Yang Ye, Xiang; Winslow, Gary M.

2000-01-01

Mouse mammary tumor virus (MMTV) superantigens (vSAgs) can undergo intercellular transfer in vivo and in vitro such that a vSAg can be presented to T cells by major histocompatibility complex (MHC) class II proteins on antigen-presenting cells (APCs) that do not express the superantigen. This process may allow T-cell activation to occur prior to viral infection. Consistent with these findings, vSAg produced by Chinese hamster ovary (CHO) cells was readily transferred to class II IE and IA (H-2k and H-2d) proteins on a B-cell lymphoma or mouse splenocytes. Fixed class II-expressing acceptor cells were used to demonstrate that the vSAg, but not the class II proteins, underwent intercellular transfer, indicating that vSAg binding to class II MHC could occur directly at the cell surface. Intercellular transfer also occurred efficiently to splenocytes from endogenous retrovirus-free mice, indicating that other proviral proteins were not involved. Presentation of vSAg7 produced by a class II-negative, furin protease-deficient CHO variant (FD11) was unsuccessful, indicating that proteolytic processing was a requisite event and that proteolytic activity could not be provided by an endoprotease on the acceptor APC. Furthermore, vSAg presentation was effected using cell-free supernatant from class II-negative, vSAg-positive cells, indicating that a soluble molecule, most likely produced by proteolytic processing, was sufficient to stimulate T cells. Because the membrane-proximal endoproteolytic cleavage site in the vSAg (residues 68 to 71) was not necessary for intercellular transfer, the data support the notion that the carboxy-terminal endoproteolytic cleavage product is an active vSAg moiety. PMID:10954523

Disruption of the Arabidopsis Defense Regulator Genes SAG101, EDS1, and PAD4 Confers Enhanced Freezing Tolerance

PubMed Central

Chen, Qin-Fang; Xu, Le; Tan, Wei-Juan; Chen, Liang; Qi, Hua; Xie, Li-Juan; Chen, Mo-Xian; Liu, Bin-Yi; Yu, Lu-Jun; Yao, Nan; Zhang, Jian-Hua; Shu, Wensheng; Xiao, Shi

2017-01-01

In Arabidopsis, three lipase-like regulators, SAG101, EDS1, and PAD4, act downstream of resistance protein-associated defense signaling. Although the roles of SAG101, EDS1, and PAD4 in biotic stress have been extensively studied, little is known about their functions in plant responses to abiotic stresses. Here, we show that SAG101, EDS1, and PAD4 are involved in the regulation of freezing tolerance in Arabidopsis. With or without cold acclimation, the sag101, eds1, and pad4 single mutants, as well as their double mutants exhibited similarly enhanced tolerance to freezing temperatures. Upon cold exposure, the sag101, eds1, and pad4 mutants showed increased transcript levels of C-REPEAT/DRE BINDING FACTORs and their regulons, compared with wild type. Moreover, freezing-induced cell death and accumulation of hydrogen peroxide were ameliorated in sag101, eds1, and pad4 mutants. The sag101, eds1, and pad4 mutants had much lower salicylic acid (SA) and diacylglycerol (DAG) contents than wild type and exogenous application of SA and DAG compromised the freezing tolerance of the mutants. Furthermore, SA suppressed the cold-induced expression of DGATs and DGKs in wild-type leaves. These findings indicate that SAG101, EDS1, and PAD4 are involved in freezing response in Arabidopsis, at least in part, by modulating the homeostasis of SA and DAG. PMID:26149542

Applying PWM to control overcurrents at unbalanced faults of force-commutated VSCs used as static var compensators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, Y.; Ekstroem, A.

1997-01-01

This study is devoted to investigating the possibility of controlling the overcurrent of a forced-commutated voltage source converter (VSC) by PWM when the ac system is undergoing large unbalanced disturbance. The converter is supposed to be used as a static var compensator at a high power level. A novel control strategy is proposed for controlling the reactive current and the dc side voltage independently. Digital simulation results are presented and compared with the results by using just the reactive current control with fundamental switching frequency.

Voltage regulation in linear induction accelerators

DOEpatents

Parsons, W.M.

1992-12-29

Improvement in voltage regulation in a linear induction accelerator wherein a varistor, such as a metal oxide varistor, is placed in parallel with the beam accelerating cavity and the magnetic core is disclosed. The non-linear properties of the varistor result in a more stable voltage across the beam accelerating cavity than with a conventional compensating resistance. 4 figs.

Genetic Characterization of Toxoplasma gondii Isolates from Pigs in Jilin Province, Northeastern China.

PubMed

Jiang, Hai-Hai; Wang, Shu-Chao; Huang, Si-Yang; Zhao, Lei; Wang, Ze-Dong; Zhu, Xing-Quan; Liu, Quan

2016-02-01

Toxoplasma gondii is prevalent in humans and animals worldwide. The present study aimed to determine the genetic diversity of T. gondii isolates from pigs in Jilin province, northeastern China. A total of 100 DNA samples were extracted from the hilar lymph nodes of slaughtered pigs, and 9 (9.0%, 95% confidence interval: 3.4-14.6%) were detected positive for T. gondii B1 gene by a nested polymerase chain reaction (PCR). The positive DNA samples were typed at 11 genetic markers, including 10 nuclear loci (SAG1, 5'-SAG2, and 3'-SAG2, alternative SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, and PK1) and an apicoplast locus (Apico) using the multilocus PCR-restriction fragment length polymorphism technology. Only three isolates were completely typed at all loci, showing that they all belonged to the clonal type I. One isolate was typed at five loci, including 5' +3'-SAG2, SAG2, SAG3, GRA6, and L358, revealing the possible clonal type I. This is the first report of the genetic characterization of T. gondii isolates in pigs in Jilin province, northeastern China, which has implications for better understanding the population structure of T. gondii infection in China.

Prostate implant reconstruction from C-arm images with motion-compensated tomosynthesis

PubMed Central

Dehghan, Ehsan; Moradi, Mehdi; Wen, Xu; French, Danny; Lobo, Julio; Morris, W. James; Salcudean, Septimiu E.; Fichtinger, Gabor

2011-01-01

Purpose: Accurate localization of prostate implants from several C-arm images is necessary for ultrasound-fluoroscopy fusion and intraoperative dosimetry. The authors propose a computational motion compensation method for tomosynthesis-based reconstruction that enables 3D localization of prostate implants from C-arm images despite C-arm oscillation and sagging. Methods: Five C-arm images are captured by rotating the C-arm around its primary axis, while measuring its rotation angle using a protractor or the C-arm joint encoder. The C-arm images are processed to obtain binary seed-only images from which a volume of interest is reconstructed. The motion compensation algorithm, iteratively, compensates for 2D translational motion of the C-arm by maximizing the number of voxels that project on a seed projection in all of the images. This obviates the need for C-arm full pose tracking traditionally implemented using radio-opaque fiducials or external trackers. The proposed reconstruction method is tested in simulations, in a phantom study and on ten patient data sets. Results: In a phantom implanted with 136 dummy seeds, the seed detection rate was 100% with a localization error of 0.86 ± 0.44 mm (Mean ± STD) compared to CT. For patient data sets, a detection rate of 99.5% was achieved in approximately 1 min per patient. The reconstruction results for patient data sets were compared against an available matching-based reconstruction method and showed relative localization difference of 0.5 ± 0.4 mm. Conclusions: The motion compensation method can successfully compensate for large C-arm motion without using radio-opaque fiducial or external trackers. Considering the efficacy of the algorithm, its successful reconstruction rate and low computational burden, the algorithm is feasible for clinical use. PMID:21992346

Molecular analysis of Toxoplasma gondii Surface Antigen 1 (SAG1) gene cloned from Toxoplasma gondii DNA isolated from Javanese acute toxoplasmosis

NASA Astrophysics Data System (ADS)

Haryati, Sri; Agung Prasetyo, Afiono; Sari, Yulia; Dharmawan, Ruben

2018-05-01

Toxoplasma gondii Surface Antigen 1 (SAG1) is often used as a diagnostic tool due to its immunodominant-specific as antigen. However, data of the Toxoplasma gondii SAG1 protein from Indonesian isolate is limited. To study the protein, genomic DNA was isolated from a Javanese acute toxoplasmosis blood samples patient. A complete coding sequence of Toxoplasma gondii SAG1 was cloned and inserted into an Escherichia coli expression plasmid and sequenced. The sequencing results were subjected to bioinformatics analysis. The Toxoplasma gondii SAG1 complete coding sequences were successfully cloned. Physicochemical analysis revealed the 336 aa of SAG1 had 34.7 kDa of weight. The isoelectric point and aliphatic index were 8.4 and 78.4, respectively. The N-terminal methionine half-life in Escherichia coli was more than 10 hours. The antigenicity, secondary structure, and identification of the HLA binding motifs also had been discussed. The results of this study would contribute information about Toxoplasma gondii SAG1 and benefits for further works willing to develop diagnostic and therapeutic strategies against the parasite.

The effect of electrostatic and gravity force on offset wire inside tube

NASA Astrophysics Data System (ADS)

Oh, S. H.; Hazineh, D.; Wang, C.

2018-04-01

In a straw-tube detector, a wire that is offset with respect to the tube axis experiences a Coulomb force when high voltage is applied between the anode wire and the tube. This force results in a shifting of the wire and straw, in addition to the gravitational sag, and is a function of the tube and wire radius, initial offset, high voltage, tension and length. The presence of such effects is well known, but the precise magnitude of the shift for the anode wires under conditions of detector operation have not been previously documented with measurable confidence. In this work, we provide the first systematic measurements for the wire shift in straw-tube detectors due to gravity and the electrostatic force using an x-ray scanner developed for the Mu2e experiment. The data are compared to the solutions of the differential equations governing the system, and we find a good match between the two. The solutions can predict the final wire and straw positions from the initial positions measured without the high voltage, and the final wire and straw positions can then be used as an input to the track reconstruction software to improve the track position resolution.

A new open-loop fiber optic gyro error compensation method based on angular velocity error modeling.

PubMed

Zhang, Yanshun; Guo, Yajing; Li, Chunyu; Wang, Yixin; Wang, Zhanqing

2015-02-27

With the open-loop fiber optic gyro (OFOG) model, output voltage and angular velocity can effectively compensate OFOG errors. However, the model cannot reflect the characteristics of OFOG errors well when it comes to pretty large dynamic angular velocities. This paper puts forward a modeling scheme with OFOG output voltage u and temperature T as the input variables and angular velocity error Δω as the output variable. Firstly, the angular velocity error Δω is extracted from OFOG output signals, and then the output voltage u, temperature T and angular velocity error Δω are used as the learning samples to train a Radial-Basis-Function (RBF) neural network model. Then the nonlinear mapping model over T, u and Δω is established and thus Δω can be calculated automatically to compensate OFOG errors according to T and u. The results of the experiments show that the established model can be used to compensate the nonlinear OFOG errors. The maximum, the minimum and the mean square error of OFOG angular velocity are decreased by 97.0%, 97.1% and 96.5% relative to their initial values, respectively. Compared with the direct modeling of gyro angular velocity, which we researched before, the experimental results of the compensating method proposed in this paper are further reduced by 1.6%, 1.4% and 1.42%, respectively, so the performance of this method is better than that of the direct modeling for gyro angular velocity.

A New Open-Loop Fiber Optic Gyro Error Compensation Method Based on Angular Velocity Error Modeling

PubMed Central

Zhang, Yanshun; Guo, Yajing; Li, Chunyu; Wang, Yixin; Wang, Zhanqing

2015-01-01

With the open-loop fiber optic gyro (OFOG) model, output voltage and angular velocity can effectively compensate OFOG errors. However, the model cannot reflect the characteristics of OFOG errors well when it comes to pretty large dynamic angular velocities. This paper puts forward a modeling scheme with OFOG output voltage u and temperature T as the input variables and angular velocity error Δω as the output variable. Firstly, the angular velocity error Δω is extracted from OFOG output signals, and then the output voltage u, temperature T and angular velocity error Δω are used as the learning samples to train a Radial-Basis-Function (RBF) neural network model. Then the nonlinear mapping model over T, u and Δω is established and thus Δω can be calculated automatically to compensate OFOG errors according to T and u. The results of the experiments show that the established model can be used to compensate the nonlinear OFOG errors. The maximum, the minimum and the mean square error of OFOG angular velocity are decreased by 97.0%, 97.1% and 96.5% relative to their initial values, respectively. Compared with the direct modeling of gyro angular velocity, which we researched before, the experimental results of the compensating method proposed in this paper are further reduced by 1.6%, 1.4% and 1.2%, respectively, so the performance of this method is better than that of the direct modeling for gyro angular velocity. PMID:25734642

Network for minimizing current imbalances in a faradaic battery

DOEpatents

Wozniak, Walter; Haskins, Harold J.

1994-01-01

A circuit for connecting a faradaic battery with circuitry for monitoring the condition of the battery includes a plurality of voltage divider networks providing battery voltage monitoring nodes and includes compensating resistors connected with the networks to maintain uniform discharge currents through the cells of the battery. The circuit also provides a reduced common mode voltage requirement for the monitoring circuitry by referencing the divider networks to one-half the battery voltage.

An Energy Saving Green Plug Device for Nonlinear Loads

NASA Astrophysics Data System (ADS)

Bloul, Albe; Sharaf, Adel; El-Hawary, Mohamed

2018-03-01

The paper presents a low cost a FACTS Based flexible fuzzy logic based modulated/switched tuned arm filter and Green Plug compensation (SFC-GP) scheme for single-phase nonlinear loads ensuring both voltage stabilization and efficient energy utilization. The new Green Plug-Switched filter compensator SFC modulated LC-Filter PWM Switched Capacitive Compensation Devices is controlled using a fuzzy logic regulator to enhance power quality, improve power factor at the source and reduce switching transients and inrush current conditions as well harmonic contents in source current. The FACTS based SFC-GP Device is a member of family of Green Plug/Filters/Compensation Schemes used for efficient energy utilization, power quality enhancement and voltage/inrush current/soft starting control using a dynamic error driven fuzzy logic controller (FLC). The device with fuzzy logic controller is validated using the Matlab / Simulink Software Environment for enhanced power quality (PQ), improved power factor and reduced inrush currents. This is achieved using modulated PWM Switching of the Filter-Capacitive compensation scheme to cope with dynamic type nonlinear and inrush cyclical loads..

Optically triggered high voltage switch network and method for switching a high voltage

DOEpatents

El-Sharkawi, Mohamed A.; Andexler, George; Silberkleit, Lee I.

1993-01-19

An optically triggered solid state switch and method for switching a high voltage electrical current. A plurality of solid state switches (350) are connected in series for controlling electrical current flow between a compensation capacitor (112) and ground in a reactive power compensator (50, 50') that monitors the voltage and current flowing through each of three distribution lines (52a, 52b and 52c), which are supplying three-phase power to one or more inductive loads. An optical transmitter (100) controlled by the reactive power compensation system produces light pulses that are conveyed over optical fibers (102) to a switch driver (110') that includes a plurality of series connected optical triger circuits (288). Each of the optical trigger circuits controls a pair of the solid state switches and includes a plurality of series connected resistors (294, 326, 330, and 334) that equalize or balance the potential across the plurality of trigger circuits. The trigger circuits are connected to one of the distribution lines through a trigger capacitor (340). In each switch driver, the light signals activate a phototransistor (300) so that an electrical current flows from one of the energy reservoir capacitors through a pulse transformer (306) in the trigger circuit, producing gate signals that turn on the pair of serially connected solid state switches (350).

Scientific Goals and Objectives for the Human Exploration of Mars: 1. Biology and Atmosphere/Climate

NASA Technical Reports Server (NTRS)

Levine, Joel S.; Garvin, J. B.; Anbar, A. D.; Beaty, D. W.; Bell, M. S.; Clancy, R. T.; Cockell, C. S.; Connerney, J. E.; Doran, P. T.; Delory, G.;

Induction of Th1 type-oriented humoral response through intranasal immunization of mice with SAG1-Toxoplasma gondii polymeric nanospheres.

PubMed

Naeem, Huma; Sana, Madiha; Islam, Saher; Khan, Matiullah; Riaz, Farooq; Zafar, Zunaira; Akbar, Haroon; Shehzad, Wasim; Rashid, Imran

2018-06-06

About one-third of the world population is prone to have infection with T. gondii, which can cause toxoplasmosis in the developing fetus and in people whose immune system is compromised through disease or chemotherapy. Surface antigen-1 (SAG1) is the candidate of vaccine against toxoplasmosis. Recent advances in biotechnology and nano-pharmaceuticals have made possible to formulate nanospheres of recombinant protein, which are suitable for sub-unit vaccine delivery. In current study, the local strain was obtained from cat feces as toxoplasma oocysts. Amplified 957 bp of SAG1 was cloned into pGEM-T and further sub-cloned into pET28-SAG1. BL21 bacteria were induced at different concentrations of isopropyl β-d-1-thiogalactopyranoside for the expression of rSAG1 protein. An immunoblot was developed for the confirmation of recombinant protein expression at 35 kDa that was actually recognized by anti-HIS antibodies and sera were collected from infected mice. PLGA encapsulated nanospheres of recombinant SAG1 were characterized through scanning electron microscopy. Experimental mice were intraperitoneally immunized with rSAG1 protein and intra-nasally immunized with nanosphere. The immune response was evaluated by indirect ELISA. In results intra-nasally administered rSAG1 in nanospheres appeared to elicit elevated responses of specific IgA and IgG2a than in control. Nanospheres of rSAG1 are found to be a bio-compatible candidate for the development of vaccine against T. gondii.

Nasopharyngeal infection by Streptococcus pyogenes requires superantigen-responsive Vβ-specific T cells

PubMed Central

Zeppa, Joseph J.; Kasper, Katherine J.; Mohorovic, Ivor; Mazzuca, Delfina M.

2017-01-01

The globally prominent pathogen Streptococcus pyogenes secretes potent immunomodulatory proteins known as superantigens (SAgs), which engage lateral surfaces of major histocompatibility class II molecules and T-cell receptor (TCR) β-chain variable domains (Vβs). These interactions result in the activation of numerous Vβ-specific T cells, which is the defining activity of a SAg. Although streptococcal SAgs are known virulence factors in scarlet fever and toxic shock syndrome, mechanisms by how SAgs contribute to the life cycle of S. pyogenes remain poorly understood. Herein, we demonstrate that passive immunization against the Vβ8-targeting SAg streptococcal pyrogenic exotoxin A (SpeA), or active immunization with either wild-type or a nonfunctional SpeA mutant, protects mice from nasopharyngeal infection; however, only passive immunization, or vaccination with inactive SpeA, resulted in high-titer SpeA-specific antibodies in vivo. Mice vaccinated with wild-type SpeA rendered Vβ8+ T cells poorly responsive, which prevented infection. This phenotype was reproduced with staphylococcal enterotoxin B, a heterologous SAg that also targets Vβ8+ T cells, and rendered mice resistant to infection. Furthermore, antibody-mediated depletion of T cells prevented nasopharyngeal infection by S. pyogenes, but not by Streptococcus pneumoniae, a bacterium that does not produce SAgs. Remarkably, these observations suggest that S. pyogenes uses SAgs to manipulate Vβ-specific T cells to establish nasopharyngeal infection. PMID:28794279

Phylogenetic relationship and virulence inference of Streptococcus Anginosus Group: curated annotation and whole-genome comparative analysis support distinct species designation

PubMed Central

2013-01-01

Background The Streptococcus Anginosus Group (SAG) represents three closely related species of the viridans group streptococci recognized as commensal bacteria of the oral, gastrointestinal and urogenital tracts. The SAG also cause severe invasive infections, and are pathogens during cystic fibrosis (CF) pulmonary exacerbation. Little genomic information or description of virulence mechanisms is currently available for SAG. We conducted intra and inter species whole-genome comparative analyses with 59 publically available Streptococcus genomes and seven in-house closed high quality finished SAG genomes; S. constellatus (3), S. intermedius (2), and S. anginosus (2). For each SAG species, we sequenced at least one numerically dominant strain from CF airways recovered during acute exacerbation and an invasive, non-lung isolate. We also evaluated microevolution that occurred within two isolates that were cultured from one individual one year apart. Results The SAG genomes were most closely related to S. gordonii and S. sanguinis, based on shared orthologs and harbor a similar number of proteins within each COG category as other Streptococcus species. Numerous characterized streptococcus virulence factor homologs were identified within the SAG genomes including; adherence, invasion, spreading factors, LPxTG cell wall proteins, and two component histidine kinases known to be involved in virulence gene regulation. Mobile elements, primarily integrative conjugative elements and bacteriophage, account for greater than 10% of the SAG genomes. S. anginosus was the most variable species sequenced in this study, yielding both the smallest and the largest SAG genomes containing multiple genomic rearrangements, insertions and deletions. In contrast, within the S. constellatus and S. intermedius species, there was extensive continuous synteny, with only slight differences in genome size between strains. Within S. constellatus we were able to determine important SNPs and changes in VNTR numbers that occurred over the course of one year. Conclusions The comparative genomic analysis of the SAG clarifies the phylogenetics of these bacteria and supports the distinct species classification. Numerous potential virulence determinants were identified and provide a foundation for further studies into SAG pathogenesis. Furthermore, the data may be used to enable the development of rapid diagnostic assays and therapeutics for these pathogens. PMID:24341328

An anthropogenic origin of the "Sirente crater," Abruzzi, Italy

NASA Astrophysics Data System (ADS)

Speranza, Fabio; Sagnotti, Leonardo; Rochette, Pierre

2004-04-01

In this paper, we review the recent hypothesis, based mostly on geomorphological features, that a ~130 m-wide sag pond, surrounded by a saddle-shaped rim from the Sirente plain (Abruzzi, Italy), is the first-discovered meteoritic crater of Italy. Sub-circular depressions (hosting ponds), with geomorphological features and size very similar to those exhibited by the main Sirente sag, are exposed in other neighboring intermountain karstic plains from Abruzzi. We have sampled present day soils from these sag ponds and from the Sirente sags (both the main "crater" and some smaller ones, recently interpreted as a crater field) and various Abruzzi paleosols from excavated trenches with an age range encompassing the estimated age of the "Sirente crater." For all samples, we measured the magnetic susceptibility and determined the Ni and Cr contents of selected specimens. The results show that the magnetic susceptibility values and the geochemical composition are similar for all samples (from Sirente and other Abruzzi sags) and are both significantly different from the values reported for soils contaminated by meteoritic dust. No solid evidence pointing at an impact origin exists, besides the circular shape and rim of the main sag. The available observations and data suggest that the "Sirente crater," together with analogous large sags in the Abruzzi intermountain plains, have to be attributed to the historical phenomenon of "transumanza" (seasonal migration of sheep and shepherds), a custom that for centuries characterized the basic social-economical system of the Abruzzi region. Such sags were excavated to provide water for millions of sheep, which spent summers in the Abruzzi karstic high pasture lands, on carbonatic massifs deprived of natural superficial fresh water. Conversely, the distribution of the smaller sags from the Sirente plain correlates with the local pattern of the calcareous bedrock and, together with the characteristics of their internal structure, are best interpreted as natural dolines. In fact, reported radiocarbon ages for the formation of the main sag pond and of the smaller sags differ (significantly) by more than two millennia, thus excluding that they were all contemporaneously formed by a meteoritic impact.

A transient-enhanced NMOS low dropout voltage regulator with parallel feedback compensation

NASA Astrophysics Data System (ADS)

Han, Wang; Lin, Tan

2016-02-01

This paper presents a transient-enhanced NMOS low-dropout regulator (LDO) for portable applications with parallel feedback compensation. The parallel feedback structure adds a dynamic zero to get an adequate phase margin with a load current variation from 0 to 1 A. A class-AB error amplifier and a fast charging/discharging unit are adopted to enhance the transient performance. The proposed LDO has been implemented in a 0.35 μm BCD process. From experimental results, the regulator can operate with a minimum dropout voltage of 150 mV at a maximum 1 A load and IQ of 165 μA. Under the full range load current step, the voltage undershoot and overshoot of the proposed LDO are reduced to 38 mV and 27 mV respectively.

Voltage Analysis Improvement of 150 kV Transmission Subsystem Using Static Synchronous Compensator (STATCOM)

NASA Astrophysics Data System (ADS)

Akbar, P. A.; Hakim, D. L.; Sucita, T.

2018-02-01

In this research, testing improvements to the distribution voltage electricity at 150 kV transmission subsystem Bandung Selatan and New Ujungberung using Flexible AC Transmission System (FACTS) technology. One of them is by doing the control of active and reactive power through the power electronics equipment Static Synchronous Compensator (STATCOM). The subsystem is tested because it has a voltage profile are relatively less well when based on the IEEE / ANSI C.84.1 (142.5 - 157.5 kV). This study was conducted by analyzing the Newton-Raphson power flow on the simulator DigSilent Power Factory 15 to determine the profile of the voltage (V) on the system. Bus which has the lowest voltage to be a reference in the installation of STATCOM. From this research is known that the voltage on the conditions of the existing bus 28, as many as 21-23 still below standard buses (142.5 kV), after the installation is done using STATCOM, voltage on the buses improved by increasing the number of tracks that follow the standard / is in the range 142.5 kV -157.5 kV as many as 23-27 buses or 78.6% - 96%, with the optimum mounting on a bus Rancaekek STATCOM II with a capacity of 300 MVA.

High voltage DC power supply

DOEpatents

Droege, T.F.

1989-12-19

A high voltage DC power supply having a first series resistor at the output for limiting current in the event of a short-circuited output, a second series resistor for sensing the magnitude of output current, and a voltage divider circuit for providing a source of feedback voltage for use in voltage regulation is disclosed. The voltage divider circuit is coupled to the second series resistor so as to compensate the feedback voltage for a voltage drop across the first series resistor. The power supply also includes a pulse-width modulated control circuit, having dual clock signals, which is responsive to both the feedback voltage and a command voltage, and also includes voltage and current measuring circuits responsive to the feedback voltage and the voltage developed across the second series resistor respectively. 7 figs.

High voltage DC power supply

DOEpatents

Droege, Thomas F.

1989-01-01

A high voltage DC power supply having a first series resistor at the output for limiting current in the event of a short-circuited output, a second series resistor for sensing the magnitude of output current, and a voltage divider circuit for providing a source of feedback voltage for use in voltage regulation is disclosed. The voltage divider circuit is coupled to the second series resistor so as to compensate the feedback voltage for a voltage drop across the first series resistor. The power supply also includes a pulse-width modulated control circuit, having dual clock signals, which is responsive to both the feedback voltage and a command voltage, and also includes voltage and current measuring circuits responsive to the feedback voltage and the voltage developed across the second series resistor respectively.

Compensation of voltage drops in solid-state switches used with thermoelectric generators

NASA Technical Reports Server (NTRS)

Shimada, K.

1972-01-01

Seebeck effect solid state switch was developed eliminating thermoelectric generator switch voltage drops. Semiconductor switches were fabricated from materials with large Seebeck coefficients, arranged such that Seebeck potential is generated with such polarity that current flow is aided.

Evidence that antibodies against recombinant SnSAG1 of Sarcocystis neurona merozoites are involved in infection and immunity in equine protozoal myeloencephalitis.

PubMed

Ellison, Siobhan; Witonsky, Sharon

2009-07-01

Sarcocystis neurona is the principal etiologic agent of equine protozoal myeloencephalitis (EPM). An immunodominant protein of S. neurona, SnSAG-1, is expressed by the majority of S. neurona merozoites isolated from spinal tissues of horses diagnosed with EPM and may be a candidate for diagnostic tests and prophylaxis for EPM. Five horses were vaccinated with adjuvanted recombinant SnSAG1 (rSnSAG1) and 5 control (sham vaccinated) horses were vaccinated with adjuvant only. Serum was evaluated pre- and post-vaccination, prior to challenge, for antibodies against rSnSAG1 and inhibitory effects on the infectivity of S. neurona by an in vitro serum neutralization assay. The effect of vaccination with rSnSAG1 on in vivo infection by S. neurona was evaluated by challenging all the horses with S. neurona merozoites. Blinded daily examinations and 4 blinded neurological examinations were used to evaluate the presence of clinical signs of EPM. The 5 vaccinated horses developed serum and cerebrospinal fluid (CSF) titers of SnSAG1, detected by enzyme-linked immunosorbent assay (ELISA), post-vaccination. Post-vaccination serum from vaccinated horses was found to have an inhibitory effect on merozoites, demonstrated by in vitro bioassay. Following the challenge, the 5 control horses displayed clinical signs of EPM, including ataxia. While 4 of the 5 vaccinated horses did not become ataxic. One rSnSAG-1 vaccinated horse showed paresis in 1 limb with muscle atrophy. All horses showed mild, transient, cranial nerve deficits; however, disease did not progress to ataxia in rSnSAG-1 vaccinated horses. The study showed that vaccination with rSnSAG-1 produced antibodies in horses that neutralized merozoites when tested by in vitro culture and significantly reduced clinical signs demonstrated by in vivo challenge.

Evidence that antibodies against recombinant SnSAG1 of Sarcocystis neurona merozoites are involved in infection and immunity in equine protozoal myeloencephalitis

PubMed Central

Ellison, Siobhan; Witonsky, Sharon

2009-01-01

Sarcocystis neurona is the principal etiologic agent of equine protozoal myeloencephalitis (EPM). An immunodominant protein of S. neurona, SnSAG-1, is expressed by the majority of S. neurona merozoites isolated from spinal tissues of horses diagnosed with EPM and may be a candidate for diagnostic tests and prophylaxis for EPM. Five horses were vaccinated with adjuvanted recombinant SnSAG1 (rSnSAG1) and 5 control (sham vaccinated) horses were vaccinated with adjuvant only. Serum was evaluated pre- and post-vaccination, prior to challenge, for antibodies against rSnSAG1 and inhibitory effects on the infectivity of S. neurona by an in vitro serum neutralization assay. The effect of vaccination with rSnSAG1 on in vivo infection by S. neurona was evaluated by challenging all the horses with S. neurona merozoites. Blinded daily examinations and 4 blinded neurological examinations were used to evaluate the presence of clinical signs of EPM. The 5 vaccinated horses developed serum and cerebrospinal fluid (CSF) titers of SnSAG1, detected by enzyme-linked immunosorbent assay (ELISA), post-vaccination. Post-vaccination serum from vaccinated horses was found to have an inhibitory effect on merozoites, demonstrated by in vitro bioassay. Following the challenge, the 5 control horses displayed clinical signs of EPM, including ataxia. While 4 of the 5 vaccinated horses did not become ataxic. One rSnSAG-1 vaccinated horse showed paresis in 1 limb with muscle atrophy. All horses showed mild, transient, cranial nerve deficits; however, disease did not progress to ataxia in rSnSAG-1 vaccinated horses. The study showed that vaccination with rSnSAG-1 produced antibodies in horses that neutralized merozoites when tested by in vitro culture and significantly reduced clinical signs demonstrated by in vivo challenge. PMID:19794889

Generation of constant-amplitude radio-frequency sweeps at a tunnel junction for spin resonance STM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paul, William; Lutz, Christopher P.; Heinrich, Andreas J.

2016-07-15

We describe the measurement and successful compensation of the radio-frequency transfer function of a scanning tunneling microscope over a wide frequency range (15.5–35.5 GHz) and with high dynamic range (>50 dB). The precise compensation of cabling resonances and attenuations is critical for the production of constant-voltage frequency sweeps for electric-field driven electron spin resonance (ESR) experiments. We also demonstrate that a well-calibrated tunnel junction voltage is necessary to avoid spurious ESR peaks that can arise due to a non-flat transfer function.

Formation Mechanisms for Spur and Groove Features on Fringing Reefs

NASA Astrophysics Data System (ADS)

Bramante, J. F.; Ashton, A. D.; Perron, J. T.

2016-12-01

Spur and groove systems (SAGs) are ubiquitous morphological features found on fore-reef slopes globally. SAGs consist of parallel, roughly shore-normal ridges of actively growing coral and coralline algae (spurs) separated by offshore-sloping depressions typically carpeted by a veneer of sediment (grooves). Although anecdotal observations and recent statistical analyses have reported correlations between wave exposure and the distribution of SAGs on fore-reef slopes, the physical mechanisms driving SAG formation remain poorly understood. For example, there remains significant debate regarding the importance of coral growth versus bed erosion for SAG formation. Here we investigate a hypothesis that SAG formation is controlled by feedbacks between sediment production and diffusion and coral growth. Using linear stability analysis, we find that sediment production, coral growth, and the feedbacks between them are unable to produce stable periodic structures without a sediment sink. However, if incipient grooves act as conduits for sediment transport offshore, a positive feedback can develop as the groove bed erodes through wave-driven abrasion during offshore transport. Eventually a negative feedback slows groove deepening when the groove bed is armored by sediment, and the groove bed relaxes to a sediment-veneered equilibrium profile analogous to sediment-rich shorefaces. To test this hypothesis, we apply a numerical model that incorporates coral growth and sediment production, sediment diffusion, non-linear wave-driven abrasion, and sediment advection offshore. This model produces the periodic, linear features characteristic of SAG morphology. The relative magnitude of growth, production, diffusion, abrasion, and advection rates affect periodic spacing or wavelength of the modeled SAGs. Finally, we evaluate the ability of the model to replicate geographical variability in SAG characteristics using previously published datasets and reanalysis wave data.

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 to optimal utilization of compensation devices and available transfer capability as well as reduce system outages through better regulation of power operating voltages.

Superantigens Are Critical for Staphylococcus aureus Infective Endocarditis, Sepsis, and Acute Kidney Injury

PubMed Central

Salgado-Pabón, Wilmara; Breshears, Laura; Spaulding, Adam R.; Merriman, Joseph A.; Stach, Christopher S.; Horswill, Alexander R.; Peterson, Marnie L.; Schlievert, Patrick M.

2013-01-01

ABSTRACT Infective endocarditis and kidney infections are serious complications of Staphylococcus aureus sepsis. We investigated the role of superantigens (SAgs) in the development of lethal sepsis, infective endocarditis, and kidney infections. SAgs cause toxic shock syndrome, but it is unclear if SAgs contribute to infective endocarditis and kidney infections secondary to sepsis. We show in the methicillin-resistant S. aureus strain MW2 that lethal sepsis, infective endocarditis, and kidney infections in rabbits are critically dependent on high-level SAgs. In contrast, the isogenic strain lacking staphylococcal enterotoxin C (SEC), the major SAg in this strain, is attenuated in virulence, while complementation restores disease production. SAgs’ role in infective endocarditis appears to be both superantigenicity and direct endothelial cell stimulation. Maintenance of elevated blood pressure by fluid therapy significantly protects from infective endocarditis, possibly through preventing bacterial accumulation on valves and increased SAg elimination. These data should facilitate better methods to manage these serious illnesses. PMID:23963178

Enhanced High Performance Power Compensation Methodology by IPFC Using PIGBT-IDVR

PubMed Central

Arumugom, Subramanian; Rajaram, Marimuthu

2015-01-01

Currently, power systems are involuntarily controlled without high speed control and are frequently initiated, therefore resulting in a slow process when compared with static electronic devices. Among various power interruptions in power supply systems, voltage dips play a central role in causing disruption. The dynamic voltage restorer (DVR) is a process based on voltage control that compensates for line transients in the distributed system. To overcome these issues and to achieve a higher speed, a new methodology called the Parallel IGBT-Based Interline Dynamic Voltage Restorer (PIGBT-IDVR) method has been proposed, which mainly spotlights the dynamic processing of energy reloads in common dc-linked energy storage with less adaptive transition. The interline power flow controller (IPFC) scheme has been employed to manage the power transmission between the lines and the restorer method for controlling the reactive power in the individual lines. By employing the proposed methodology, the failure of a distributed system has been avoided and provides better performance than the existing methodologies. PMID:26613101

Long, elliptically bent, active X-ray mirrors with slope errors <200 nrad.

PubMed

Nistea, Ioana T; Alcock, Simon G; Kristiansen, Paw; Young, Adam

2017-05-01

Actively bent X-ray mirrors are important components of many synchrotron and X-ray free-electron laser beamlines. A high-quality optical surface and good bending performance are essential to ensure that the X-ray beam is accurately focused. Two elliptically bent X-ray mirror systems from FMB Oxford were characterized in the optical metrology laboratory at Diamond Light Source. A comparison of Diamond-NOM slope profilometry and finite-element analysis is presented to investigate how the 900 mm-long mirrors sag under gravity, and how this deformation can be adequately compensated using a single, spring-loaded compensator. It is shown that two independent mechanical actuators can accurately bend the trapezoidal substrates to a range of elliptical profiles. State-of-the-art residual slope errors of <200 nrad r.m.s. are achieved over the entire elliptical bending range. High levels of bending repeatability (ΔR/R = 0.085% and 0.156% r.m.s. for the two bending directions) and stability over 24 h (ΔR/R = 0.07% r.m.s.) provide reliable beamline performance.

KSI's Cross Insulated Core Transformer Technology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Uhmeyer, Uwe

2009-08-04

Cross Insulated Core Transformer (CCT) technology improves on Insulated Core Transformer (ICT) implementations. ICT systems are widely used in very high voltage, high power, power supply systems. In an ICT transformer ferrite core sections are insulated from their neighboring ferrite cores. Flux leakage is present at each of these insulated gaps. The flux loss is raised to the power of stages in the ICT design causing output voltage efficiency to taper off with increasing stages. KSI's CCT technology utilizes a patented technique to compensate the flux loss at each stage of an ICT system. Design equations to calculate the fluxmore » compensation capacitor value are presented. CCT provides corona free operation of the HV stack. KSI's CCT based High Voltage power supply systems offer high efficiency operation, high frequency switching, low stored energy and smaller size over comparable ICT systems.« less

A 13.56 MHz CMOS Active Rectifier With Switched-Offset and Compensated Biasing for Biomedical Wireless Power Transfer Systems.

PubMed

Yan Lu; Wing-Hung Ki

2014-06-01

A full-wave active rectifier switching at 13.56 MHz with compensated bias current for a wide input range for wirelessly powered high-current biomedical implants is presented. The four diodes of a conventional passive rectifier are replaced by two cross-coupled PMOS transistors and two comparator- controlled NMOS switches to eliminate diode voltage drops such that high voltage conversion ratio and power conversion efficiency could be achieved even at low AC input amplitude |VAC|. The comparators are implemented with switched-offset biasing to compensate for the delays of active diodes and to eliminate multiple pulsing and reverse current. The proposed rectifier uses a modified CMOS peaking current source with bias current that is quasi-inversely proportional to the supply voltage to better control the reverse current over a wide AC input range (1.5 to 4 V). The rectifier was fabricated in a standard 0.35 μm CMOS N-well process with active area of 0.0651 mm(2). For the proposed rectifier measured at |VAC| = 3.0 V, the voltage conversion ratios are 0.89 and 0.93 for RL=500 Ω and 5 kΩ, respectively, and the measured power conversion efficiencies are 82.2% to 90.1% with |VAC| ranges from 1.5 to 4 V for RL=500 Ω.

Superantigens Modulate Bacterial Density during Staphylococcus aureus Nasal Colonization

PubMed Central

Xu, Stacey X.; Kasper, Katherine J.; Zeppa, Joseph J.; McCormick, John K.

2015-01-01

Superantigens (SAgs) are potent microbial toxins that function to activate large numbers of T cells in a T cell receptor (TCR) Vβ-specific manner, resulting in excessive immune system activation. Staphylococcus aureus possesses a large repertoire of distinct SAgs, and in the context of host-pathogen interactions, staphylococcal SAg research has focused primarily on the role of these toxins in severe and invasive diseases. However, the contribution of SAgs to colonization by S. aureus remains unclear. We developed a two-week nasal colonization model using SAg-sensitive transgenic mice expressing HLA-DR4, and evaluated the role of SAgs using two well-studied stains of S. aureus. S. aureus Newman produces relatively low levels of staphylococcal enterotoxin A (SEA), and although we did not detect significant TCR-Vβ specific changes during wild-type S. aureus Newman colonization, S. aureus Newman Δsea established transiently higher bacterial loads in the nose. S. aureus COL produces relatively high levels of staphylococcal enterotoxin B (SEB), and colonization with wild-type S. aureus COL resulted in clear Vβ8-specific T cell skewing responses. S. aureus COL Δseb established consistently higher bacterial loads in the nose. These data suggest that staphylococcal SAgs may be involved in regulating bacterial densities during nasal colonization. PMID:26008236

Recombinant vaccines against T. gondii: comparison between homologous and heterologous vaccination protocols using two viral vectors expressing SAG1.

PubMed

Mendes, Érica Araújo; Fonseca, Flavio G; Casério, Bárbara M; Colina, Janaína P; Gazzinelli, Ricardo Tostes; Caetano, Braulia C

2013-01-01

The use of recombinant viral vectors expressing T. gondii antigens is a safe and efficient approach to induce immune response against the parasite and a valuable tool for vaccine development. We have previously protected mice from toxoplasmosis by immunizing the animals with an adenovirus expressing the protein SAG1 (AdSAG1) of T. gondii. We are now looking for ways to improve the vaccination strategy and enhance protection. One limitation of homologous vaccinations (sequential doses of the same vector) is induction of anti-vector immune response that blocks cell transduction, restricts transgene expression and, consequently, compromises the overall outcome of vaccination. One way to avert the effects of anti-vector response is to use different viruses in prime and boost (heterologous vaccination). Bearing this in mind, we generated a modified Vaccinia Virus Ankara encoding SAG1 (MVASAG1), to be tested as boost agent after prime with AdSAG1. Although minor differences were observed in the magnitude of the anti-SAG1 immune response induced by each vaccination protocol, the heterologous immunization with AdSAG1 followed by MVASAG1 resulted in improved capacity to control brain cyst formation in a model of chronic toxoplasmosis in C57BL/6 mice.

New low-level a-c amplifier provides adjustable noise cancellation and automatic temperature compensation

NASA Technical Reports Server (NTRS)

Smith, J. R., Jr.

1964-01-01

Circuit utilizing a transistorized differential amplifier is developed for biomedical use. This low voltage operating circuit provides adjustable cancellation at the input for unbalanced noise signals, and automatic temperature compensation is accomplished by a single active element across the input-output ends.

A visible-light-driven core-shell like Ag2S@Ag2CO3 composite photocatalyst with high performance in pollutants degradation.

PubMed

Yu, Changlin; Wei, Longfu; Zhou, Wanqin; Dionysiou, Dionysios D; Zhu, Lihua; Shu, Qing; Liu, Hong

2016-08-01

A series of Ag2S-Ag2CO3 (4%, 8%, 16%, 32% and 40% Ag2S), Ag2CO3@Ag2S (32%Ag2S) and Ag2S@Ag2CO3 (32%Ag2S) composite photocatalysts were fabricated by coprecipitation or successive precipitation reaction. The obtained catalysts were analyzed by N2 physical adsorption, powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, UV-vis diffuse reflectance spectroscopy and photocurrent test. Under visible light irradiation, the influences of Ag2S content and core-shell property on photocatalytic activity and stability were evaluated in studies focused on the degradation of methyl orange (MO) dye, phenol, and bisphenol A. Results showed that excellent photocatalytic performance was obtained over Ag2S/Ag2CO3 composite photocatalysts with respect to Ag2S and Ag2CO3. With optimal content of Ag2S (32 wt%), the Ag2S-Ag2CO3 showed the highest photocatalytic degradation efficiency. Moreover, the structured property of Ag2S/Ag2CO3 greatly influenced the activity. Compared with Ag2S-Ag2CO3 and Ag2CO3@Ag2S, core-shell like Ag2S@Ag2CO3 demonstrated the highest activity and stability. The main reason for the boosting of photocatalytic performance was due to the formation of Ag2S/Ag2CO3 well contacted interface and unique electron structures. Ag2S/Ag2CO3 interface could significantly increase the separation efficiency of the photo-generated electrons (e(-)) and holes (h(+)), and production of OH radicals. More importantly, the low solubility of Ag2S shell could effectively protect the core of Ag2CO3, which further guarantees the stability of Ag2CO3. Copyright © 2016 Elsevier Ltd. All rights reserved.

Bacterial Superantigens Promote Acute Nasopharyngeal Infection by Streptococcus pyogenes in a Human MHC Class II-Dependent Manner

PubMed Central

Kasper, Katherine J.; Zeppa, Joseph J.; Wakabayashi, Adrienne T.; Xu, Stacey X.; Mazzuca, Delfina M.; Welch, Ian; Baroja, Miren L.; Kotb, Malak; Cairns, Ewa; Cleary, P. Patrick; Haeryfar, S. M. Mansour; McCormick, John K.

2014-01-01

Establishing the genetic determinants of niche adaptation by microbial pathogens to specific hosts is important for the management and control of infectious disease. Streptococcus pyogenes is a globally prominent human-specific bacterial pathogen that secretes superantigens (SAgs) as ‘trademark’ virulence factors. SAgs function to force the activation of T lymphocytes through direct binding to lateral surfaces of T cell receptors and class II major histocompatibility complex (MHC-II) molecules. S. pyogenes invariably encodes multiple SAgs, often within putative mobile genetic elements, and although SAgs are documented virulence factors for diseases such as scarlet fever and the streptococcal toxic shock syndrome (STSS), how these exotoxins contribute to the fitness and evolution of S. pyogenes is unknown. Here we show that acute infection in the nasopharynx is dependent upon both bacterial SAgs and host MHC-II molecules. S. pyogenes was rapidly cleared from the nasal cavity of wild-type C57BL/6 (B6) mice, whereas infection was enhanced up to ∼10,000-fold in B6 mice that express human MHC-II. This phenotype required the SpeA superantigen, and vaccination with an MHC –II binding mutant toxoid of SpeA dramatically inhibited infection. Our findings indicate that streptococcal SAgs are critical for the establishment of nasopharyngeal infection, thus providing an explanation as to why S. pyogenes produces these potent toxins. This work also highlights that SAg redundancy exists to avoid host anti-SAg humoral immune responses and to potentially overcome host MHC-II polymorphisms. PMID:24875883

Facile synthesis of S-Ag nanocomposites and Ag2S short nanorods by the interaction of sulfur with AgNO3 in PEG400

NASA Astrophysics Data System (ADS)

Zhang, Yan-Li; Xie, Xin-Yuan; Liang, Ming; Xie, Shu-Ming; Chen, Jie-Mei; Zheng, Wen-Jie

2016-06-01

A facile, eco-friendly and inexpensive method to prepare Ag2S short nanorods and S-Ag nanocomposites using sublimed sulfur, AgNO3, PVP and PEG400 was studied. According to x-ray diffraction and scanning electron microscopy of the Ag2S, the products are highly crystalline and pure Ag2S nanorods with diameters of 70-160 nm and lengths of 200-360 nm. X-ray diffraction of the S-Ag nanocomposites shows that we obtained cubic Ag and S nanoparticles. Transmission electron microscopy shows that the molar ratio of PVP to Ag+ plays an important role in controlling the size and morphology of the S-Ag nanocomposites. When the molar ratio of PVP to Ag+ was 10:1, smaller sizes, better dispersibility and narrower distribution of S-Ag nanocomposites with diameters of 10-40 nm were obtained. The formation mechanism of the S-Ag nanocomposites was studied by designing a series of experiments using ultraviolet-visible measurement, and it was found that S nanoparticles are produced first and act as seed crystals; then Ag+ becomes Ag nanocrystals on the surfaces of the S nanoparticles by the reduction of PVP. PEG400 acts as a catalyzer, accelerating the reaction rate, and protects the S-Ag nanocomposites from reacting to produce Ag2S. The antimicrobial experiments show that the S-Ag nanocomposites have greater antimicrobial activity on Staphylococcus aureus, Aspergillus niger and blue mold than Ag nanoparticles.

Generation and Surface Localization of Intact M Protein in Streptococcus pyogenes Are Dependent on sagA

PubMed Central

Biswas, Indranil; Germon, Pierre; McDade, Kathleen; Scott, June R.

2001-01-01

The M protein is an important surface-located virulence factor of Streptococcus pyogenes, the group A streptococcus (GAS). Expression of M protein is primarily controlled by Mga, a transcriptional activator protein. A recent report suggested that the sag locus, which includes nine genes necessary and sufficient for production of streptolysin S, another GAS virulence factor, is also needed for transcription of emm, encoding the M protein (Z. Li, D. D. Sledjeski, B. Kreikemeyer, A. Podbielski, and M. D. Boyle, J. Bacteriol. 181:6019–6027, 1999). To investigate this in more detail, we constructed an insertion-deletion mutation in sagA, the first gene in the sag locus, in the M6 strain JRS4. The resulting strain, JRS470, produced no detectable streptolysin S and showed a drastic reduction in cell surface-associated M protein, as measured by cell aggregation and Western blot analysis. However, transcription of the emm gene was unaffected by the sagA mutation. Detailed analysis with monoclonal antibodies and an antipeptide antibody showed that the M protein in the sagA mutant strain was truncated so that it lacks the C-repeat region and the C-terminal domain required for anchoring it to the cell surface. This truncated M protein was largely found, as expected, in the culture supernatant. Lack of surface-located M protein made the sagA mutant strain susceptible to phagocytosis. Thus, although sagA does not affect transcription of the M6 protein gene, it is needed for the surface localization of this important virulence factor. PMID:11598078

High voltage MOSFET switching circuit

DOEpatents

McEwan, Thomas E.

1994-01-01

The problem of source lead inductance in a MOSFET switching circuit is compensated for by adding an inductor to the gate circuit. The gate circuit inductor produces an inductive spike which counters the source lead inductive drop to produce a rectangular drive voltage waveform at the internal gate-source terminals of the MOSFET.

Expression and immunological characterisation of Eimeria tenella glycosylphosphatidylinositol-anchored surface antigen-5

NASA Astrophysics Data System (ADS)

Ho, Sue-Kim; Nathan, Sheila; Wan, Kiew-Lian

2016-11-01

Eimeria tenella is the most pathogenic of the Eimeria species that infect chickens and causes huge economic losses to the poultry industry. The glycosylphosphatidylinositol-anchored surface antigen-5 (SAG5) found on the surface of the parasite has been shown to activate the chicken's immune system. In this study, recombinant SAG5 was expressed, purified and used to investigate the immune-inducing characteristics of the molecule. Chickens were immunized with purified recombinant SAG5 and sera were subjected to Enzyme-linked Immunosorbant Assay (ELISA). Results indicated that specific antibodies against rSAG5 were produced, with IgG detected at a higher level compared to IgA and IgM. Information on the immunological responses elicited by SAG5 provides essential knowledge that will contribute towards the effort to develop more effective strategies against coccidiosis.

Characteristics of an Airfoil as Affected by Fabric Sag

NASA Technical Reports Server (NTRS)

Ward, Kenneth E

1932-01-01

This report presents the results of tests made at a high value of the Reynolds Number in the N.A.C.A. variable-density wind tunnel to determine the aerodynamic characteristics of an airfoil as affected by fabric sag. Tests were made of two Gottingen 387 airfoils, one having the usual smooth surface and the other having a surface modified to simulate two types of fabric sag. The results of these tests indicate that the usual sagging of the wind covering between ribs has a very small effect on the aerodynamic characteristics of an airfoil.

Clonal deletion of T cell repertoires with specific T cell receptor Vβ chains by two endogenous superantigens in NC/Nga mice.

PubMed

Ohkusu-Tsukada, Kozo; Tsukada, Teruyo; Takahashi, Kimimasa

2017-11-01

Superantigens (SAgs) are powerful T-cell stimulatory proteins. Because an atopic dermatitis (AD) model NC/Nga mice had two endogenous SAgs, namely minor lymphocyte-stimulating locus-1 a (Mls-1 a ) and mouse mammary tumor virus (MMTV)(SHN), SAg-responsive T-cells bearing Vβ5.1, Vβ6, Vβ8.1, Vβ8.2, Vβ8.3, Vβ9, and Vβ11 should be endogenously deleted. Here, we discuss that the endogenous SAgs-expression may be involved in AD-sensitivity in NC/Nga mice.

Extremum Seeking Control of Smart Inverters for VAR Compensation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arnold, Daniel; Negrete-Pincetic, Matias; Stewart, Emma

2015-09-04

Reactive power compensation is used by utilities to ensure customer voltages are within pre-defined tolerances and reduce system resistive losses. While much attention has been paid to model-based control algorithms for reactive power support and Volt Var Optimization (VVO), these strategies typically require relatively large communications capabilities and accurate models. In this work, a non-model-based control strategy for smart inverters is considered for VAR compensation. An Extremum Seeking control algorithm is applied to modulate the reactive power output of inverters based on real power information from the feeder substation, without an explicit feeder model. Simulation results using utility demand informationmore » confirm the ability of the control algorithm to inject VARs to minimize feeder head real power consumption. In addition, we show that the algorithm is capable of improving feeder voltage profiles and reducing reactive power supplied by the distribution substation.« less

Performance of Four-Leg VSC based DSTATCOM using Single Phase P-Q Theory

NASA Astrophysics Data System (ADS)

Jampana, Bangarraju; Veramalla, Rajagopal; Askani, Jayalaxmi

2017-02-01

This paper presents single-phase P-Q theory for four-leg VSC based distributed static compensator (DSTATCOM) in the distribution system. The proposed DSTATCOM maintains unity power factor at source, zero voltage regulation, eliminates current harmonics, load balancing and neutral current compensation. The advantage of using four-leg VSC based DSTATCOM is to eliminate isolated/non-isolated transformer connection at point of common coupling (PCC) for neutral current compensation. The elimination of transformer connection at PCC with proposed topology will reduce cost of DSTATCOM. The single-phase P-Q theory control algorithm is used to extract fundamental component of active and reactive currents for generation of reference source currents which is based on indirect current control method. The proposed DSTATCOM is modelled and the results are validated with various consumer loads under unity power factor and zero voltage regulation modes in the MATLAB R2013a environment using simpower system toolbox.

Power Quality Improvement in Induction Furnace by Harmonic Reduction Using Dynamic Voltage Restorer

NASA Astrophysics Data System (ADS)

Saggu, Tejinder Singh; Singh, Lakhwinder

2016-06-01

Induction furnaces are used in wide quantity under different capacities for annual production of around 25 million tons of iron and steel in India. It plays a vital role in various manufacturing processes around the world for melting different types of metal scraps i. e. Copper, Cast Iron, Aluminium, Steel, Brass, Bronze, Silicon, Gold, Silver etc. which are further used in many other industrial applications. The induction furnace causes a huge disturbance to the utility and nearby consumers during its operation due to its non-linear characteristics. This is a serious phenomenon responsible for power quality degradation in the power system. This paper presents methodology to improve the power quality degradation caused by induction furnace using Dynamic Voltage Restorer (DVR) which is a type of custom power device. The real time data has been taken from an industry employing induction furnace for production of ingots from scrap material. The experimental readings are measured using power quality analyser equipment. The simulation of whole plant is done by analysing this same data and the simulation results are compared with actual onsite results. Then, solution methodology using DVR is presented which revealed that the implementation of DVR is an effective solution for voltage sag mitigation and harmonics improvement in induction furnace.

Voltage stability index based optimal placement of static VAR compensator and sizing using Cuckoo search algorithm

NASA Astrophysics Data System (ADS)

Venkateswara Rao, B.; Kumar, G. V. Nagesh; Chowdary, D. Deepak; Bharathi, M. Aruna; Patra, Stutee

2017-07-01

This paper furnish the new Metaheuristic algorithm called Cuckoo Search Algorithm (CSA) for solving optimal power flow (OPF) problem with minimization of real power generation cost. The CSA is found to be the most efficient algorithm for solving single objective optimal power flow problems. The CSA performance is tested on IEEE 57 bus test system with real power generation cost minimization as objective function. Static VAR Compensator (SVC) is one of the best shunt connected device in the Flexible Alternating Current Transmission System (FACTS) family. It has capable of controlling the voltage magnitudes of buses by injecting the reactive power to system. In this paper SVC is integrated in CSA based Optimal Power Flow to optimize the real power generation cost. SVC is used to improve the voltage profile of the system. CSA gives better results as compared to genetic algorithm (GA) in both without and with SVC conditions.

Acoustic Beam Forming Array Using Feedback-Controlled Microphones for Tuning and Self-Matching of Frequency Response

NASA Technical Reports Server (NTRS)

Radcliffe, Eliott (Inventor); Naguib, Ahmed (Inventor); Humphreys, Jr., William M. (Inventor)

2014-01-01

A feedback-controlled microphone includes a microphone body and a membrane operatively connected to the body. The membrane is configured to be initially deflected by acoustic pressure such that the initial deflection is characterized by a frequency response. The microphone also includes a sensor configured to detect the frequency response of the initial deflection and generate an output voltage indicative thereof. The microphone additionally includes a compensator in electric communication with the sensor and configured to establish a regulated voltage in response to the output voltage. Furthermore, the microphone includes an actuator in electric communication with the compensator, wherein the actuator is configured to secondarily deflect the membrane in opposition to the initial deflection such that the frequency response is adjusted. An acoustic beam forming microphone array including a plurality of the above feedback-controlled microphones is also disclosed.

Relationships among superantigen toxin gene profiles, genotypes, and pathogenic characteristics of Staphylococcus aureus isolates from bovine mastitis.

PubMed

Wang, Dong; Zhang, Limei; Yong, Changfu; Shen, Mingliang; Ali, Tariq; Shahid, Muhammad; Han, Kun; Zhou, Xuezhang; Han, Bo

2017-06-01

Staphylococcus aureus is one of the major etiological agents of bovine mastitis, harboring a wide variety of staphylococcal superantigen (SAg) toxin genes. The SAg toxin genes are reported to be closely associated with the pathogenicity of the Staph. aureus causing the bovine mastitis. This study was conducted to investigate SAg toxin gene profiles and to assess the relationships among SAg toxin genes, genotypes of Staph. aureus, and their pathogenic properties. A total of 327 quarter milk samples were collected from bovine mastitis cases for isolation and identification of pathogens. In total, 35 isolates were identified as Staph. aureus, and the prevalence of Staph. aureus in milk samples was 13.6% (35/256). Polymerase chain reaction (PCR) and randomly amplified polymorphic DNA (RAPD) assays were used to detect the SAg toxin genes and to genotype Staph. aureus strains isolated from milk samples of bovine mastitis in 10 dairy herds located in Ningxia, China, respectively. The results showed that among the Staph. aureus isolates (n = 35), 71.4% (n = 25) of isolates carried at least one SAg toxin gene. In total, 18 SAg genes and 21 different gene combination patterns were detected among these isolates. The most common SAg genes in Staph. aureus isolates were sei, sen, and seu (44.0% each), followed by seo, tst, and etB (28.0% each), etA (24.0%), sem and sep (16.0% each), seb, sec, sed, and sek (12.0% each), and sea and seh genes (8.0% each); the seg, sej, and ser genes were present in 4.0% of the isolates. Three gene combinations were found to be related to mobile genetic elements that carried 2 or more genes. The egc-cluster of the seg-sei-sem-sen-seo genes, located on the pathogenicity island Type I υSaβ, was detected in 16% of isolates. Interestingly, we observed 6 RAPD genotypes (I to VI) in Staph. aureus isolates, and 2 of these genotypes were strongly associated with the severity of bovine mastitis; there was a close relationship between the RAPD genotypes and SAg genes. Isolates of RAPD type III were more frequently associated with clinical and subclinical mastitis, whereas strains of type VI were mostly related to subclinical mastitis. In addition, SAg genes were related to severity of bovine mastitis. We conclude that an obvious relationship exists among RAPD genotypes, SAg toxin genes, and severity of bovine mastitis. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Case-control study of pneumonia patients with Streptococcus anginosus group bacteria in their sputum.

PubMed

Hirai, Jun; Sakanashi, Daisuke; Haranaga, Shusaku; Kinjo, Takeshi; Hagihara, Mao; Kato, Hideo; Suematsu, Hiroyuki; Yamagishi, Yuka; Fujita, Jiro; Mikamo, Hiroshige

2016-12-01

In recent years, Streptococcus anginosus group (SAG) bacteria are becoming increasingly recognized as important pneumonia-causing pathogens. Although several small studies have been reported, the features of SAG pneumonia remain unclear, because the identification of SAG from sputum cultures is not routinely performed in most microbiology laboratories. The aim of this study was to elucidate the clinical characteristics of SAG pneumonia. This was a retrospective case-control study utilizing data obtained in our hospital between September 2009 and June 2016. We investigated 31 patients with SAG pneumonia (PWP), and also assessed the difference between the 31 PWP and 37 patients without pneumonia (PWOP) in whose sputum SAG was detected. Seventy-one percent of the patients were men and the median age was 78 years in the PWP. Univariate analysis indicated that the PWP were significantly more often a bed-ridden (p < 0.01) with comorbid aspiration than were the PWOP (p < 0.05). Among the PWP, nursing and healthcare-associated pneumonia (NHCAP) was the more common type of pneumonia (54.8%). S. anginosus was detected significantly more frequently in sputum cultures of PWP than PWOP (p < 0.01), and multiple pathogens were detected more frequently in PWP (p < 0.01). Streptococcus constellatus was the most frequently detected pathogen in patients with a single bacterial infection. Empyema was observed only in patients with multiple bacteria. SAG should be recognized as important causative pathogens of pneumonia, particularly among elderly patients with underlying disease associated with aspiration. NHCAP was the more common type of SAG pneumonia in this study. Copyright © 2016 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

African eggplant (Solanum anguivi Lam.) fruit with bioactive polyphenolic compounds exerts in vitro antioxidant properties and inhibits Ca(2+)-induced mitochondrial swelling.

PubMed

Elekofehinti, Olusola Olalekan; Kamdem, Jean Paul; Bolingon, Aline Augusti; Athayde, Margareth Linde; Lopes, Seeger Rodrigo; Waczuk, Emily Pansera; Kade, Ige Joseph; Adanlawo, Isaac Gbadura; Rocha, Joao Batista Teixeira

2013-10-01

To evaluate the antioxidant and radical scavenging activities of Solanum anguivi fruit (SAG) and its possible effect on mitochondrial permeability transition pore as well as mitochondrial membrane potential (ΔΨm) isolated from rat liver. Antioxidant activity of SAG was assayed by using 2,2-diphenyl-1-picrylhydrazyl (DPPH), reducing power, iron chelation and ability to inhibit lipid peroxidation in both liver and brain homogenate of rats. Also, the effect of SAG on mitochondrial membrane potential and mitochondrial swelling were determined. Identification and quantification of bioactive polyphenolics was done by HPLC-DAD. SAG exhibited potent and concentration dependent free radical-scavenging activity (IC50/DPPH=275.03±7.8 μg/mL). Reductive and iron chelation abilities also increase with increase in SAG concentration. SAG also inhibited peroxidation of cerebral and hepatic lipids subjected to iron oxidative assault. SAG protected against Ca(2+) (110 μmol/L)-induced mitochondrial swelling and maintained the ΔΨm. HPLC analysis revealed the presence of gallic acid [(17.54±0.04) mg/g], chlorogenic acid (21.90±0.02 mg/g), caffeic acid (16.64±0.01 mg/g), rutin [(14.71±0.03) mg/g] and quercetin [(7.39±0.05) mg/g]. These effects could be attributed to the bioactive polyphenolic compounds present in the extract. Our results suggest that SAG extract is a potential source of natural antioxidants that may be used not only in pharmaceutical and food industry but also in the treatment of diseases associated with oxidative stress. Copyright © 2013 Asian Pacific Tropical Biomedical Magazine. Published by Elsevier B.V. All rights reserved.

The mechanism of post-rift fault activities in Baiyun sag, Pearl River Mouth basin

NASA Astrophysics Data System (ADS)

Sun, Zhen; Xu, Ziying; Sun, Longtao; Pang, Xiong; Yan, Chengzhi; Li, Yuanping; Zhao, Zhongxian; Wang, Zhangwen; Zhang, Cuimei

2014-08-01

Post-rift fault activities were often observed in deepwater basins, which have great contributions to oil and gas migration and accumulation. The main causes for post-rift fault activities include tectonic events, mud or salt diapirs, and gravitational collapse. In the South China Sea continental margin, post-rift fault activities are widely distributed, especially in Baiyun sag, one of the largest deepwater sag with its main body located beneath present continental slope. During the post-rift stage, large population of faults kept active for a long time from 32 Ma (T70) till 5.5 Ma (T10). Seismic interpretation, fault analysis and analogue modeling experiments indicate that the post-rift fault activities in Baiyun sag between 32 Ma (T70) and 13.8 Ma (T30) was mainly controlled by gravity pointing to the Main Baiyun sag, which caused the faults extensive on the side facing Main Baiyun sag and the back side compressive. Around 32 Ma (T70), the breakup of the continental margin and the spreading of the South China Sea shed a combined effect of weak compression toward Baiyun sag. The gravity during post-rift stage might be caused by discrepant subsidence and sedimentation between strongly thinned sag center and wing areas. This is supported by positive relationship between sedimentation rate and fault growth index. After 13.8 Ma (T30), fault activity shows negative relationship with sedimentation rate. Compressive uplift and erosion in seismic profiles as well as negative tectonic subsiding rates suggest that the fault activity from 13.8 Ma (T30) to 5.5 Ma (T10) might be controlled by the subductive compression from the Philippine plate in the east.

A compensation method for the full phase retardance nonuniformity in phase-only liquid crystal on silicon spatial light modulators.

PubMed

Teng, Long; Pivnenko, Mike; Robertson, Brian; Zhang, Rong; Chu, Daping

2014-10-20

A simple and efficient compensation method for the full correction of both the anisotropic and isotropic nonuniformity of the light phase retardance in a liquid crystal (LC) layer is presented. This is achieved by accurate measurement of the spatial variation of the LC layer's thickness with the help of a calibrated liquid crystal wedge, rather than solely relying on the light intensity profile recorded using two crossed polarizers. Local phase retardance as a function of the applied voltage is calculated with its LC thickness and a set of reference data measured from the intensity of the reflected light using two crossed polarizers. Compensation of the corresponding phase nonuniformity is realized by applying adjusted local voltage signals for different grey levels. To demonstrate its effectiveness, the proposed method is applied to improve the performance of a phase-only liquid crystal on silicon (LCOS) spatial light modulator (SLM). The power of the first diffraction order measured with the binary phase gratings compensated by this method is compared with that compensated by the conventional crossed-polarizer method. The results show that the phase compensation method proposed here can increase the dynamic range of the first order diffraction power significantly from 15~21 dB to over 38 dB, while the crossed-polarizer method can only increase it to 23 dB.

Histoplasma Urinary Antigen Testing Obviates the Need for Coincident Serum Antigen Testing.

PubMed

Libert, Diane; Procop, Gary W; Ansari, Mohammad Q

2018-03-07

Serum and urine antigen (SAg, UAg) detection are common tests for Histoplasma capsulatum. UAg detection is more widely used and reportedly has a higher sensitivity. We investigated whether SAg detection contributes meaningfully to the initial evaluation of patients with suspected histoplasmosis. We reviewed 20,285 UAg and 1,426 SAg tests ordered from 1997 to 2016 and analyzed paired UAg and SAg tests completed on the same patient within 1 week. We determined the positivity rate for each test. Of 601 paired specimens, 542 were concurrent negatives and 48 were concurrent positives (98% agreement). Medical records were available for eight of 11 pairs with discrepant results. UAg was falsely positive in six instances, truly positive once, and falsely negative once. These findings support using a single antigen detection test, rather than both UAg and SAg, as an initial screen for suspected histoplasmosis. This aligns with the current practice of most physicians.

Dynamic characteristic of electromechanical coupling effects in motor-gear system

NASA Astrophysics Data System (ADS)

Bai, Wenyu; Qin, Datong; Wang, Yawen; Lim, Teik C.

2018-06-01

Dynamic characteristics of an electromechanical model which combines a nonlinear permeance network model (PNM) of a squirrel-cage induction motor and a coupled lateral-torsional dynamic model of a planetary geared rotor system is analyzed in this study. The simulations reveal the effects of internal excitations or parameters like machine slotting, magnetic saturation, time-varying mesh stiffness and shaft stiffness on the system dynamics. The responses of the electromechanical system with PNM motor model are compared with those responses of the system with dynamic motor model. The electromechanical coupling due to the interactions between the motor and gear system are studied. Furthermore, the frequency analysis of the electromechanical system dynamic characteristics predicts an efficient way to detect work condition of unsymmetrical voltage sag.

47 CFR 73.51 - Determining operating power.

Code of Federal Regulations, 2014 CFR

2014-10-01

...'s input power directly from the RF voltage, RF current, and phase angle; or (2) calculating the... dissipative network in the antenna system shall be made on FCC Form 302. The technical information supplied on... transmitter output within a tolerance of ±10 percent, to compensate for variations in line voltage or other...

47 CFR 73.51 - Determining operating power.

Code of Federal Regulations, 2012 CFR

2012-10-01

...'s input power directly from the RF voltage, RF current, and phase angle; or (2) calculating the... dissipative network in the antenna system shall be made on FCC Form 302. The technical information supplied on... transmitter output within a tolerance of ±10 percent, to compensate for variations in line voltage or other...

47 CFR 73.51 - Determining operating power.

Code of Federal Regulations, 2013 CFR

2013-10-01

...'s input power directly from the RF voltage, RF current, and phase angle; or (2) calculating the... dissipative network in the antenna system shall be made on FCC Form 302. The technical information supplied on... transmitter output within a tolerance of ±10 percent, to compensate for variations in line voltage or other...

High voltage MOSFET switching circuit

DOEpatents

McEwan, T.E.

1994-07-26

The problem of source lead inductance in a MOSFET switching circuit is compensated for by adding an inductor to the gate circuit. The gate circuit inductor produces an inductive spike which counters the source lead inductive drop to produce a rectangular drive voltage waveform at the internal gate-source terminals of the MOSFET. 2 figs.

Radiation Hardened Structured ASIC Platform with Compensation of Delay for Temperature and Voltage Variations for Multiple Redundant Temporal Voting Latch Technology

NASA Technical Reports Server (NTRS)

Ardalan, Sasan (Inventor)

2018-01-01

The invention relates to devices and methods of maintaining the current starved delay at a constant value across variations in voltage and temperature to increase the speed of operation of the sequential logic in the radiation hardened ASIC design.

Control of Grid Connected Photovoltaic System Using Three-Level T-Type Inverter

NASA Astrophysics Data System (ADS)

Zorig, Abdelmalik; Belkeiri, Mohammed; Barkat, Said; Rabhi, Abdelhamid

2016-08-01

Three-level T-Type inverter (3LT2I) topology has numerous advantageous compared to three-level neutral-point-clamped (NPC) inverter. The main benefits of 3LT2I inverter are the efficiency, inverter cost, switching losses, and the quality of output voltage waveforms. In this paper, a photovoltaic distributed generation system based on dual-stage topology of DC-DC boost converter and 3LT2I is introduced. To that end, a decoupling control strategy of 3LT2I is proposed to control the current injected into the grid, reactive power compensation, and DC-link voltage. The resulting system is able to extract the maximum power from photovoltaic generator, to achieve sinusoidal grid currents, and to ensure reactive power compensation. The voltage-balancing control of two split DC capacitors of the 3LT2I is achieved using three-level space vector modulation with balancing strategy based on the effective use of the redundant switching states of the inverter voltage vectors. The proposed system performance is investigated at different operating conditions.

Modified Perfect Harmonics Cancellation Control of a Grid Interfaced SPV Power Generation

NASA Astrophysics Data System (ADS)

Singh, B.; Shahani, D. T.; Verma, A. K.

2015-03-01

This paper deals with a grid interfaced solar photo voltaic (SPV) power generating system with modified perfect harmonic cancellation (MPHC) control for power quality improvement in terms of mitigation of the current harmonics, power factor correction, control of point of common coupling (PCC) voltage with reactive power compensation and load balancing in a three phase distribution system. The proposed grid interfaced SPV system consists of a SPV array, a dc-dc boost converter and a voltage source converter (VSC) used for the compensation of other connected linear and nonlinear loads at PCC. The reference grid currents are estimated using MPHC method and control signals are derived by using pulse width modulation (PWM) current controller of VSC. The SPV power is fed to the common dc bus of VSC and dc-dc boost converter using maximum power point tracking (MPPT). The dc link voltage of VSC is regulated by using dc voltage proportional integral (PI) controller. The analysis of the proposed SPV power generating system is carried out under dc/ac short circuit and severe SPV-SX and SPV-TX intrusion.

An In-Rush Current Suppression Technique for the Solid-State Transfer Switch System

NASA Astrophysics Data System (ADS)

Cheng, Po-Tai; Chen, Yu-Hsing

More and more utility companies provide dual power feeders as a premier service of high power quality and reliability. To take advantage of this, the solid-state transfer switch (STS) is adopted to protect the sensitive load against the voltage sag. However, the fast transfer process may cause in-rush current on the load-side transformer due to the resulting DC-offset in its magnetic flux as the load-transfer is completed. The in-rush current can reach 2∼6 p.u. and it may trigger the over-current protections on the power feeder. This paper develops a flux estimation scheme and a thyristor gating scheme based on the impulse commutation bridge STS (ICBSTS) to minimize the DC-offset on the magnetic flux. By sensing the line voltages of both feeders, the flux estimator can predict the peak transient flux linkage at the moment of load-transfer and evaluate a suitable moment for the transfer to minimize the in-rush current. Laboratory test results are presented to validate the performance of the proposed system.

Enzyme-linked immunosorbent assays for detection of equine antibodies specific to Sarcocystis neurona surface antigens.

PubMed

Hoane, Jessica S; Morrow, Jennifer K; Saville, William J; Dubey, J P; Granstrom, David E; Howe, Daniel K

2005-09-01

Sarcocystis neurona is the primary causative agent of equine protozoal myeloencephalitis (EPM), a common neurologic disease of horses in the Americas. We have developed a set of enzyme-linked immunosorbent assays (ELISAs) based on the four major surface antigens of S. neurona (SnSAGs) to analyze the equine antibody response to S. neurona. The SnSAG ELISAs were optimized and standardized with a sample set of 36 equine sera that had been characterized by Western blotting against total S. neurona parasite antigen, the current gold standard for S. neurona serology. The recombinant SnSAG2 (rSnSAG2) ELISA showed the highest sensitivity and specificity at 95.5% and 92.9%, respectively. In contrast, only 68.2% sensitivity and 71.4% specificity were achieved with the rSnSAG1 ELISA, indicating that this antigen may not be a reliable serological marker for analyzing antibodies against S. neurona in horses. Importantly, the ELISA antigens did not show cross-reactivity with antisera to Sarcocystis fayeri or Neospora hughesi, two other equine parasites. The accuracy and reliability exhibited by the SnSAG ELISAs suggest that these assays will be valuable tools for examining the equine immune response against S. neurona infection, which may help in understanding the pathobiology of this accidental parasite-host interaction. Moreover, with modification and further investigation, the SnSAG ELISAs have potential for use as immunodiagnostic tests to aid in the identification of horses affected by EPM.

Enzyme-Linked Immunosorbent Assays for Detection of Equine Antibodies Specific to Sarcocystis neurona Surface Antigens†

PubMed Central

Hoane, Jessica S.; Morrow, Jennifer K.; Saville, William J.; Dubey, J. P.; Granstrom, David E.; Howe, Daniel K.

2005-01-01

Sarcocystis neurona is the primary causative agent of equine protozoal myeloencephalitis (EPM), a common neurologic disease of horses in the Americas. We have developed a set of enzyme-linked immunosorbent assays (ELISAs) based on the four major surface antigens of S. neurona (SnSAGs) to analyze the equine antibody response to S. neurona. The SnSAG ELISAs were optimized and standardized with a sample set of 36 equine sera that had been characterized by Western blotting against total S. neurona parasite antigen, the current gold standard for S. neurona serology. The recombinant SnSAG2 (rSnSAG2) ELISA showed the highest sensitivity and specificity at 95.5% and 92.9%, respectively. In contrast, only 68.2% sensitivity and 71.4% specificity were achieved with the rSnSAG1 ELISA, indicating that this antigen may not be a reliable serological marker for analyzing antibodies against S. neurona in horses. Importantly, the ELISA antigens did not show cross-reactivity with antisera to Sarcocystis fayeri or Neospora hughesi, two other equine parasites. The accuracy and reliability exhibited by the SnSAG ELISAs suggest that these assays will be valuable tools for examining the equine immune response against S. neurona infection, which may help in understanding the pathobiology of this accidental parasite-host interaction. Moreover, with modification and further investigation, the SnSAG ELISAs have potential for use as immunodiagnostic tests to aid in the identification of horses affected by EPM. PMID:16148170

Genetic diversity among sea otter isolates of Toxoplasma gondii

USGS Publications Warehouse

Sundar, N.; Cole, Rebecca A.; Thomas, N.J.; Majumdar, D.; Dubey, J.P.; Su, C.

2008-01-01

Sea otters (Enhydra lutris) have been reported to become infected with Toxoplasma gondiiand at times succumb to clinical disease. Here, we determined genotypes of 39 T. gondiiisolates from 37 sea otters in two geographically distant locations (25 from California and 12 from Washington). Six genotypes were identified using 10 PCR-RFLP genetic markers including SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico, and by DNA sequencing of loci SAG1 and GRA6 in 13 isolates. Of these 39 isolates, 13 (33%) were clonal Type II which can be further divided into two groups at the locus Apico. Two of the 39 isolates had Type II alleles at all loci except a Type I allele at locus L358. One isolate had Type II alleles at all loci except the Type I alleles at loci L358 and Apico. One isolate had Type III alleles at all loci except Type II alleles at SAG2 and Apico. Two sea otter isolates had a mixed infection. Twenty-one (54%) isolates had an unique allele at SAG1 locus. Further genotyping or DNA sequence analysis for 18 of these 21 isolates at loci SAG1 and GRA6 revealed that there were two different genotypes, including the previously identified Type X (four isolates) and a new genotype named Type A (14 isolates). The results from this study suggest that the sea otter isolates are genetically diverse.

Multiple layer insulation cover

DOEpatents

Farrell, James J.; Donohoe, Anthony J.

1981-11-03

A multiple layer insulation cover for preventing heat loss in, for example, a greenhouse, is disclosed. The cover is comprised of spaced layers of thin foil covered fabric separated from each other by air spaces. The spacing is accomplished by the inflation of spaced air bladders which are integrally formed in the cover and to which the layers of the cover are secured. The bladders are inflated after the cover has been deployed in its intended use to separate the layers of the foil material. The sizes of the material layers are selected to compensate for sagging across the width of the cover so that the desired spacing is uniformly maintained when the cover has been deployed. The bladders are deflated as the cover is stored thereby expediting the storage process and reducing the amount of storage space required.

Analysis of the geological structure and tectonic evolution of Xingning-Jinghai sag in deep water area, northern South China Sea

NASA Astrophysics Data System (ADS)

Han, Xiaoying; Ren, Jianye; Lin, Zi; Yang, Linlong

2015-04-01

Recent years, oil and gas exploration of the Pearl River Mouth Basin in the northern margin of South China Sea continuously achieved historic breakthroughs. The Xingning-Jinghai sag, which is located in southeast of the Pearl River Mouth Basin, is a deep-water sag with a great exploration potential. Its tectonic evolution is extremely complex. It experienced Mesozoic subduction to Cenozoic intra-continental rifting background, and finally evolved into a deep-water sag of the northern continental margin of South China Sea. The geological characteristics and the tectonic evolution of Xingning-Jinghai sag was closely related to the process of formation and evolution of the passive continental margin of the northern South China Sea. It is confirmed by many geophysical data that compared with adjacent Chaoshan depression, the crustal thickness of Xingning-Jinghai sag was rapidly thinning, and it developed detachment faults with later magmatic intrusion. The development of detachment faults have dynamic significance for the spreading of the South China Sea. Based on the seismic geological interpretation of 2D seismic data in the study area, the characteristics of detachment fault and supra-detachment basin have been proposed in this study. The characteristics of the detachment fault are low angle and high ratio between heave and throw. The geometry of the detachment fault is a typical lisric shape, with the dip of fault decreasing generally from the seismic profile. The detachment basin where sediments are not deposited over a tilting hanging-wall block but onto a tectonically exhumed footwall which is different from the typical half graben basin. Seismic profiles indicate two different structural styles in the east and west part of Xingning-Jinghai sag. In the west of the sag, there developed two large detachment faults, which control their detachment basin systems and the typical H block, and the two detachment faults are dipping landward and seaward, respectively. In the east, affected by the later volcanic activities, Xingning-Jinghai sag deformed complicatedly and developed a series of landward dipping faults, showing the compound graben structure. Combined with the fault activity quantitative calculation, basin subsidence history and other advanced technology, the basin tectonic evolution has been divided into rift stage and post-rift stage. Considering the extension development evolution of Xingning-Jinghai sag and the extension and thinning of lithosphere under the background of spreading of the South China Sea, we argue that the northern margin of the South China lithosphere experienced an intense stretching and thinning stage. At this period, the subsidence of the Xingning-Jinghai sag was controlled by the detachment faults, indicating a rifting stage. With the development of the detachment faults, the thickness of crust was extremely thinned. After the spreading of the South China Sea the whole sag entered into the depression period which was characterized by thermal subsidence.

Battery charge control with temperature compensated voltage limit

NASA Technical Reports Server (NTRS)

Thierfelder, H. E.

1983-01-01

Battery charge control for orbiting spacecraft with mission durations from three to ten years, is a critical design feature that is discussed. Starting in 1974, the General Electric Space Systems Division designed, manufactured and tested battery systems for six different space programs. Three of these are geosynchronous missions, two are medium altitude missions and one is a near-earth mission. All six power subsystems contain nickel cadmium batteries which are charged using a temperature compensated voltage limit. This charging method was found to be successful in extending the life of nickel cadmium batteries in all three types of earth orbits. Test data and flight data are presented for each type of orbit.

Temperature compensated and self-calibrated current sensor

DOEpatents

Yakymyshyn, Christopher Paul; Brubaker, Michael Allen; Yakymyshyn, Pamela Jane

2007-09-25

A method is described to provide temperature compensation and reduction of drift due to aging for a current sensor based on a plurality of magnetic field sensors positioned around a current carrying conductor. The offset voltage signal generated by each magnetic field sensor is used to correct variations in the output signal due to temperature variations and aging.

Cloning and Expression of Major Surface Antigen 1 Gene of Toxoplasma gondii RH Strain Using the Expression Vector pVAX1 in Chinese Hamster Ovary Cells

PubMed Central

Abdizadeh, Rahman; Maraghi, Sharif; Ghadiri, Ata A.; Tavalla, Mehdi; Shojaee, Saeedeh

2015-01-01

Background: Toxoplasmosis is an opportunistic protozoan infection with a high prevalence in a broad range of hosts infecting up to one-third of the world human population. Toxoplasmosis leads to serious medical problems in immunocompromised individuals and fetuses and also induces abortion and mortality in domestic animals. Therefore, there is a huge demand for the development of an effective vaccine. Surface Antigen 1 (SAG1) is one of the important immunodominant surface antigens of Toxoplasma gondii, which interacts with host cells and primarily involved in adhesion, invasion and stimulation of host immune response. Surface antigen 1 is considered as the leading candidate for development of an effective vaccine against toxoplasmosis. Objectives: The purpose of this study was to clone the major surface antigen1 gene (SAG1) from the genotype 1 of T. gondii, RH strain into the eukaryotic expression vector pVAX1 in order to use for a DNA vaccine. Materials and Methods: Genomic DNA was extracted from tachyzoite of the parasite using the QIAamp DNA mini kit. After designing the specific primers, SAG1 gene was amplified by Polymerase Chain Reaction (PCR). The purified PCR products were then cloned into a pPrime plasmid vector. The aforementioned product was subcloned into the pVAX1 eukaryotic expression vector. The recombinant pVAX1-SAG1 was then transfected into Chinese Hamster Ovary (CHO) cells and expression of SAG1 antigen was evaluated using Reverse Transcriptase Polymerase Chain Reaction (RT-PCR), Immunofluorescence Assay (IFA) and Western Blotting (WB). Results: The cloning and subcloning products (pPrime-SAG1 and pVAX1-SAG1 plasmid vectors) of SAG1 gene were verified and confirmed by enzyme digestion and sequencing. A 30 kDa recombinant protein was expressed in CHO cells as shown by IFA and WB methods. Conclusions: The pVAX1 expression vector and CHO cells are a suitable system for high-level recombinant protein production for SAG1 gene from T. gondii parasites and are promising approaches for antigen preparation in vaccine development. PMID:25861441

DOE Office of Scientific and Technical Information (OSTI.GOV)

King, M. P.; Kaplar, R. J.; Dickerson, J. R.

Electrical performance and characterization of deep levels in vertical GaN P-i-N diodes grown on low threading dislocation density (~10 4 –10 6 cm –2) bulk GaN substrates are investigated. The lightly doped n drift region of these devices is observed to be highly compensated by several prominent deep levels detected using deep level optical spectroscopy at E c-2.13, 2.92, and 3.2 eV. A combination of steady-state photocapacitance and lighted capacitance-voltage profiling indicates the concentrations of these deep levels to be N t = 3 × 10 12, 2 × 10 15, and 5 × 10 14 cm –3, respectively. Themore » E c-2.92 eV level is observed to be the primary compensating defect in as-grown n-type metal-organic chemical vapor deposition GaN, indicating this level acts as a limiting factor for achieving controllably low doping. The device blocking voltage should increase if compensating defects reduce the free carrier concentration of the n drift region. Understanding the incorporation of as-grown and native defects in thick n-GaN is essential for enabling large V BD in the next-generation wide-bandgap power semiconductor devices. Furthermore, controlling the as-grown defects induced by epitaxial growth conditions is critical to achieve blocking voltage capability above 5 kV.« less

Detection of antibodies against Sarcocystis neurona, Neospora spp., and Toxoplasma gondii in horses from Costa Rica.

PubMed

Dangoudoubiyam, S; Oliveira, J B; Víquez, C; Gómez-García, A; González, O; Romero, J J; Kwok, O C H; Dubey, J P; Howe, D K

2011-06-01

Serum samples from 315 horses from Costa Rica, Central America, were examined for the presence of antibodies against Sarcocystis neurona, Neospora spp., and Toxoplasma gondii by using the surface antigen (SAG) SnSAG2 enzyme-linked immunosorbent assay (ELISA), the NhSAG1 ELISA, and the modified agglutination test, respectively. Anti- S. neurona antibodies were found in 42.2% of the horses by using the SnSAG2 ELISA. Anti- Neospora spp. antibodies were found in only 3.5% of the horses by using the NhSAG1 ELISA, and only 1 of these horses was confirmed seropositive by Western blot. Antibodies to T. gondii were found in 34.0% of the horses tested, which is higher than in previous reports from North and South America. The finding of anti- S. neurona antibodies in horses from geographical areas where Didelphis marsupialis has wide distribution suggests that D. marsupialis is a potential definitive host for this parasite and a source of infection for these horses.

Capability-Based Modeling Methodology: A Fleet-First Approach to Architecture

DTIC Science & Technology

2014-02-01

reconnaissance (ISR) aircraft , or unmanned systems . Accordingly, a mission architecture used to model SAG operations for a given Fleet unit should include all...would use an ISR aircraft to increase fidelity of a targeting solution; another mission thread to show how unmanned systems can augment targeting... unmanned systems . Therefore, an architect can generate, from a comprehensive SAG mission architecture, individual mission threads that model how a SAG

A new mosaic integrative and conjugative element from Streptococcus agalactiae carrying resistance genes for chloramphenicol (catQ) and macrolides [mef(I) and erm(TR)].

PubMed

Morici, Eleonora; Simoni, Serena; Brenciani, Andrea; Giovanetti, Eleonora; Varaldo, Pietro E; Mingoia, Marina

2017-01-01

To investigate the genetic basis of catQ-mediated chloramphenicol resistance in Streptococcus agalactiae. Two clinical strains of catQ-positive chloramphenicol-resistant S. agalactiae (Sag236 and Sag403) were recently isolated, typed (MLST, PFGE pulsotypes, capsular types) and their antibiotic resistances investigated by phenotypic and genotypic approaches. Several molecular methods (PCR mapping, restriction assays, Southern blotting, sequencing and sequence analysis, conjugal transfer assays) were used to determine the genetic context of catQ and characterize a genetic element detected in the isolates. Sag236 and Sag403 shared the same ST (ST19), but exhibited a different capsular type (III and V, respectively) and pulsotype. Both harboured the macrolide resistance genes mef(I) and erm(TR) and the tetracycline resistance gene tet(M). Accordingly, they were resistant to chloramphenicol, erythromycin and tetracycline. catQ and mef(I) were associated in an IQ module that was indistinguishable in Sag236 and Sag403. In mating assays, chloramphenicol and erythromycin resistance proved transferable, at low frequency, only from Sag236. Transconjugants carried not only catQ and mef(I), but also erm(TR), suggesting a linkage of the three resistance genes in a mobile element, which, though seemingly non-mobile, was also detected in Sag403. The new element (designated ICESag236, ∼110 kb) results from recombination of two integrative and conjugative elements (ICEs) originally described in different streptococcal species: S. agalactiae ICESagTR7, carrying erm(TR); and Streptococcus pneumoniae ICESpn529IQ, carrying the prototype IQ module. These findings strengthen the notion that widespread streptococcal ICEs may form mosaics that enhance their diversity and spread, broaden their host range and carry new cargo genes. © The Author 2016. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Evolutionary paths of streptococcal and staphylococcal superantigens

PubMed Central

2012-01-01

Background Streptococcus pyogenes (GAS) harbors several superantigens (SAgs) in the prophage region of its genome, although speG and smez are not located in this region. The diversity of SAgs is thought to arise during horizontal transfer, but their evolutionary pathways have not yet been determined. We recently completed sequencing the entire genome of S. dysgalactiae subsp. equisimilis (SDSE), the closest relative of GAS. Although speG is the only SAg gene of SDSE, speG was present in only 50% of clinical SDSE strains and smez in none. In this study, we analyzed the evolutionary paths of streptococcal and staphylococcal SAgs. Results We compared the sequences of the 12–60 kb speG regions of nine SDSE strains, five speG+ and four speG–. We found that the synteny of this region was highly conserved, whether or not the speG gene was present. Synteny analyses based on genome-wide comparisons of GAS and SDSE indicated that speG is the direct descendant of a common ancestor of streptococcal SAgs, whereas smez was deleted from SDSE after SDSE and GAS split from a common ancestor. Cumulative nucleotide skew analysis of SDSE genomes suggested that speG was located outside segments of steeper slopes than the stable region in the genome, whereas the region flanking smez was unstable, as expected from the results of GAS. We also detected a previously undescribed staphylococcal SAg gene, selW, and a staphylococcal SAg -like gene, ssl, in the core genomes of all Staphylococcus aureus strains sequenced. Amino acid substitution analyses, based on dN/dS window analysis of the products encoded by speG, selW and ssl suggested that all three genes have been subjected to strong positive selection. Evolutionary analysis based on the Bayesian Markov chain Monte Carlo method showed that each clade included at least one direct descendant. Conclusions Our findings reveal a plausible model for the comprehensive evolutionary pathway of streptococcal and staphylococcal SAgs. PMID:22900646

Partial null astigmatism-compensated interferometry for a concave freeform Zernike mirror

NASA Astrophysics Data System (ADS)

Dou, Yimeng; Yuan, Qun; Gao, Zhishan; Yin, Huimin; Chen, Lu; Yao, Yanxia; Cheng, Jinlong

2018-06-01

Partial null interferometry without using any null optics is proposed to measure a concave freeform Zernike mirror. Oblique incidence on the freeform mirror is used to compensate for astigmatism as the main component in its figure, and to constrain the divergence of the test beam as well. The phase demodulated from the partial nulled interferograms is divided into low-frequency phase and high-frequency phase by Zernike polynomial fitting. The low-frequency surface figure error of the freeform mirror represented by the coefficients of Zernike polynomials is reconstructed from the low-frequency phase, applying the reverse optimization reconstruction technology in the accurate model of the interferometric system. The high-frequency surface figure error of the freeform mirror is retrieved from the high-frequency phase adopting back propagating technology, according to the updated model in which the low-frequency surface figure error has been superimposed on the sag of the freeform mirror. Simulations verified that this method is capable of testing a wide variety of astigmatism-dominated freeform mirrors due to the high dynamic range. The experimental result using our proposed method for a concave freeform Zernike mirror is consistent with the null test result employing the computer-generated hologram.

Relation between sedimentary framework and hydrogeology in the Guarani Aquifer System in São Paulo state, Brazil

NASA Astrophysics Data System (ADS)

Hirata, Ricardo; Gesicki, Ana; Sracek, Ondra; Bertolo, Reginaldo; Giannini, Paulo César; Aravena, Ramón

2011-04-01

This paper presents the results of a new investigation of the Guarani Aquifer System (SAG) in São Paulo state. New data were acquired about sedimentary framework, flow pattern, and hydrogeochemistry. The flow direction in the north of the state is towards the southwest and not towards the west as expected previously. This is linked to the absence of SAG outcrop in the northeast of São Paulo state. Both the underlying Pirambóia Formation and the overlying Botucatu Formation possess high porosity (18.9% and 19.5%, respectively), which was not modified significantly by diagenetic changes. Investigation of sediments confirmed a zone of chalcedony cement close to the SAG outcrop and a zone of calcite cement in the deep confined zone. The main events in the SAG post-sedimentary history were: (1) adhesion of ferrugineous coatings on grains, (2) infiltration of clays in eodiagenetic stage, (3) regeneration of coatings with formation of smectites, (4) authigenic overgrowth of quartz and K-feldspar in advanced eodiagenetic stage, (5) bitumen cementation of Pirambóia Formation in mesodiagenetic stage, (6) cementation by calcite in mesodiagenetic and telodiagenetic stages in Pirambóia Formation, (7) formation of secondary porosity by dissolution of unstable minerals after appearance of hydraulic gradient and penetration of the meteoric water caused by the uplift of the Serra do Mar coastal range in the Late Cretaceous, (8) authigenesis of kaolinite and amorphous silica in unconfined zone of the SAG and cation exchange coupled with the dissolution of calcite at the transition between unconfined and confined zone, and (9) authigenesis of analcime in the confined SAG zone. The last two processes are still under operation. The deep zone of the SAG comprises an alkaline pH, Na-HCO 3 groundwater type with old water and enriched δ 13C values (<-3.9), which evolved from a neutral pH, Ca-HCO 3 groundwater type with young water and depleted δ 13C values (>-18.8) close to the SAG outcrop. This is consistent with a conceptual geochemical model of the SAG, suggesting dissolution of calcite driven by cation exchange, which occurs at a relatively narrow front recently moving downgradient at much slower rate compared to groundwater flow. More depleted values of δ 18O in the deep confined zone close to the Paraná River compared to values of relative recent recharged water indicate recharge occur during a period of cold climate. The SAG is a "storage-dominated" type of aquifer which has to be managed properly to avoid its overexploitation.

Multiharmonic rf feedforward system for compensation of beam loading and periodic transient effects in magnetic-alloy cavities of a proton synchrotron

NASA Astrophysics Data System (ADS)

Tamura, Fumihiko; Ohmori, Chihiro; Yamamoto, Masanobu; Yoshii, Masahito; Schnase, Alexander; Nomura, Masahiro; Toda, Makoto; Shimada, Taihei; Hasegawa, Katsushi; Hara, Keigo

2013-05-01

Beam loading compensation is a key for acceleration of a high intensity proton beam in the main ring (MR) of the Japan Proton Accelerator Research Complex (J-PARC). Magnetic alloy loaded rf cavities with a Q value of 22 are used to achieve high accelerating voltages without a tuning bias loop. The cavity is driven by a single harmonic (h=9) rf signal while the cavity frequency response also covers the neighbor harmonics (h=8,10). Therefore the wake voltage induced by the high intensity beam consists of the three harmonics, h=8,9,10. The beam loading of neighbor harmonics is the source of periodic transient effects and a possible source of coupled bunch instabilities. In the article, we analyze the wake voltage induced by the high intensity beam. We employ the rf feedforward method to compensate the beam loading of these three harmonics (h=8,9,10). The full-digital multiharmonic feedforward system was developed for the MR. We describe the system architecture and the commissioning methodology of the feedforward patterns. The commissioning of the feedforward system has been performed by using high intensity beams with 1.0×1014 proteins per pulse. The impedance seen by the beam is successfully reduced and the longitudinal oscillations due to the beam loading are reduced. By the beam loading compensation, stable high power beam operation is achieved. We also report the reduction of the momentum loss during the debunching process for the slow extraction by the feedforward.

Effect of ion compensation of the beam space charge on gyrotron operation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fokin, A. P.; Glyavin, M. Yu.; Nusinovich, G. S.

In gyrotrons, the coherent radiation of electromagnetic waves takes place when the cyclotron resonance condition between the wave frequency and the electron cyclotron frequency or its harmonic holds. The voltage depression caused by the beam space charge field changes the relativistic cyclotron frequency and, hence, can play an important role in the beam-wave interaction process. In long pulse and continuous-wave regimes, the beam space charge field can be partially compensated by the ions, which appear due to the beam impact ionization of neutral molecules of residual gases in the interaction space. In the present paper, the role of this ionmore » compensation of the beam space charge on the interaction efficiency is analyzed. We also analyze the effect of the electron velocity spread on the limiting currents and discuss some effects restricting the ion-to-beam electron density ratio in the saturation stage. It is shown that the effect of the ion compensation on the voltage depression caused by the beam space charge field can cause significant changes in the efficiency of gyrotron operation and, in some cases, even result in the break of oscillations.« less

Application of VSC-HVDC with Shunt Connected SMES for Compensation of Power Fluctuation

NASA Astrophysics Data System (ADS)

Linn, Zarchi; Kakigano, Hiroaki; Miura, Yushi; Ise, Toshifumi

This paper describes the application of VSC-HVDC (High Voltage DC Transmission using Voltage Source Converter) with shunt connected SMES (Superconducting Magnetic Energy Storage) for compensation of power fluctuation caused by fluctuating power source such as photovoltaics and wind turbines. The objectives of this proposed system is to smooth out fluctuating power in one terminal side of HVDC in order to avoid causing power system instability and frequency deviation by absorbing or providing power according to the system requirement while another terminal side power is fluctuated. The shunt connected SMES charges and discharges the energy to and from the dc side and it compensates required power of fluctuation to obtain constant power flow in one terminal side of VSC-HVDC system. This system configuration has ability for power system stabilization in the case of power fluctuation from natural energy source. PSCAD/EMTDC simulation is used to evaluate the performance of applied system configuration and control method.

Optimal placement of FACTS devices using optimization techniques: A review

NASA Astrophysics Data System (ADS)

Gaur, Dipesh; Mathew, Lini

2018-03-01

Modern power system is dealt with overloading problem especially transmission network which works on their maximum limit. Today’s power system network tends to become unstable and prone to collapse due to disturbances. Flexible AC Transmission system (FACTS) provides solution to problems like line overloading, voltage stability, losses, power flow etc. FACTS can play important role in improving static and dynamic performance of power system. FACTS devices need high initial investment. Therefore, FACTS location, type and their rating are vital and should be optimized to place in the network for maximum benefit. In this paper, different optimization methods like Particle Swarm Optimization (PSO), Genetic Algorithm (GA) etc. are discussed and compared for optimal location, type and rating of devices. FACTS devices such as Thyristor Controlled Series Compensator (TCSC), Static Var Compensator (SVC) and Static Synchronous Compensator (STATCOM) are considered here. Mentioned FACTS controllers effects on different IEEE bus network parameters like generation cost, active power loss, voltage stability etc. have been analyzed and compared among the devices.

Reactive Power Compensation Method Considering Minimum Effective Reactive Power Reserve

NASA Astrophysics Data System (ADS)

Gong, Yiyu; Zhang, Kai; Pu, Zhang; Li, Xuenan; Zuo, Xianghong; Zhen, Jiao; Sudan, Teng

2017-05-01

According to the calculation model of minimum generator reactive power reserve of power system voltage stability under the premise of the guarantee, the reactive power management system with reactive power compensation combined generator, the formation of a multi-objective optimization problem, propose a reactive power reserve is considered the minimum generator reactive power compensation optimization method. This method through the improvement of the objective function and constraint conditions, when the system load growth, relying solely on reactive power generation system can not meet the requirement of safe operation, increase the reactive power reserve to solve the problem of minimum generator reactive power compensation in the case of load node.

Crystallization and preliminary crystallographic analysis of a surface antigen glycoprotein, SAG19, from Eimeria tenella

PubMed Central

Ramly, Nur Zazarina; Rouzheinikov, Sergey N.; Sedelnikova, Svetlana E.; Baker, Patrick J.; Chow, Yock-Ping; Wan, Kiew-Lian; Nathan, Sheila; Rice, David W.

2013-01-01

Coccidiosis in chickens is caused by the apicomplexan parasite Eimeria tenella and is thought to involve a role for a superfamily of more than 20 cysteine-rich surface antigen glycoproteins (SAGs) in host–parasite interactions. A representative member of the family, SAG19, has been overexpressed in Escherichia coli, purified and crystallized by the hanging-drop method of vapour diffusion using ammonium sulfate as the precipitant. Crystals of SAG19 diffracted to beyond 1.50 Å resolution and belonged to space group I4, with unit-cell parameters a = b = 108.2, c = 37.5 Å. Calculation of possible values of V M suggests that there is a single molecule in the asymmetric unit. PMID:24316835

Experimental Analysis of Voltage Drop Compensation in a DC Electrified Railway by Introducing an Energy Storage System Incorporating EDLCs

NASA Astrophysics Data System (ADS)

Konishi, Takeshi; Hase, Shin-Ichi; Nakamichi, Yoshinobu; Nara, Hidetaka; Uemura, Tadashi

Interest has been shown in the concept of an energy storage system aimed at leveling load and improving energy efficiency by charging during vehicle regeneration and discharging during running. Such a system represents an efficient countermeasure against pantograph point voltage drop, power load fluctuation and regenerative power loss. We selected an EDLC model as an energy storage medium and a step-up/step-down chopper as a power converter to exchange power between the storage medium and overhead lines. Basic verification was conducted using a mini-model for DC 400V, demonstrating characteristics suitable for its use as an energy storage system. Based on these results, an energy storage system was built for DC 600V and a verification test conducted in conjunction with the Enoshima Electric Railway Co. Ltd. This paper gives its experimental analysis of voltage drop compensation in a DC electrified railway and some discussions based on the test.

Capacitive Trans-Impedance Amplifier Circuit with Charge Injection Compensation

NASA Technical Reports Server (NTRS)

Milkov, Mihail M. (Inventor); Gulbransen, David J. (Inventor)

2016-01-01

A capacitive trans-impedance amplifier circuit with charge injection compensation is provided. A feedback capacitor is connected between an inverting input port and an output port of an amplifier. A MOS reset switch has source and drain terminals connected between the inverting input and output ports of the amplifier, and a gate terminal controlled by a reset signal. The reset switch is open or inactive during an integration phase, and closed or active to electrically connect the inverting input port and output port of the amplifier during a reset phase. One or more compensation capacitors are provided that are not implemented as gate oxide or MOS capacitors. Each compensation capacitor has a first port connected to a compensation signal that is a static signal or a toggling compensation signal that toggles between two compensation voltage values, and a second port connected to the inverting input port of the amplifier.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Makarov, Yuri V.; Du, Pengwei; Etingov, Pavel V.

The document titled “WECC Variable Generation Planning Reference Book”. This book is divided into two volumes; one is the main document (volume 1)and the other is appendices (volume 2). The main document is a collection of the best practices and the information regarding the application and impact of variables generation on power system planning. This volume (appendices) has additional information on the following topics: Probabilistic load flow problems. 2. Additional useful indices. 3. high-impact low-frequency (HILF) events. 4. Examples of wide-area nomograms. 5. Transmission line ratings, types of dynamic rating methods. 6. Relative costs per MW-km of different electric powermore » transmission technologies. 7. Ultra-high voltage (UHV) transmission. 8.High voltage direct current (VSC-HVDC). 9. HVDC. 10. Rewiring of existing transmission lines. 11. High-temperature low sag (HTLS) conductors. 12. The direct method and energy functions for transient stability analysis in power systems. 13.Blackouts caused by voltage instability. 14. Algorithm for parameter continuation predictor-corrector methods. 15. Approximation techniques available for security regions. 16. Impacts of wind power on power system small signals stability. 17. FIDVR. 18. FACTS. 19. European planning standard and practices. 20. International experience in wind and solar energy sources. 21. Western Renewable Energy Zones (WREZ). 22. various energy storage technologies. 23. demand response. 24. BA consolidation and cooperation options. 25. generator power management requirements and 26. European planning guidelines.« less

Role of Dendritic Cells in the Immune Response Induced by Mouse Mammary Tumor Virus Superantigen

PubMed Central

Baribaud, Frédéric; Maillard, Ivan; Vacheron, Sonia; Brocker, Thomas; Diggelmann, Heidi; Acha-Orbea, Hans

1999-01-01

After mouse mammary tumor virus (MMTV) infection, B lymphocytes present a superantigen (Sag) and receive help from the unlimited number of CD4+ T cells expressing Sag-specific T-cell receptor Vβ elements. The infected B cells divide and differentiate, similarly to what occurs in classical B-cell responses. The amplification of Sag-reactive T cells can be considered a primary immune response. Since B cells are usually not efficient in the activation of naive T cells, we addressed the question of whether professional antigen-presenting cells such as dendritic cells (DCs) are responsible for T-cell priming. We show here, using MMTV(SIM), a viral isolate which requires major histocompatibility complex class II I-E expression to induce a strong Sag response in vivo, that transgenic mice expressing I-E exclusively on DCs (I-EαDC tg) reveal a strong Sag response. This Sag response was dependent on the presence of B cells, as indicated by the absence of stimulation in I-EαDC tg mice lacking B cells (I-EαDC tg μMT−/−), even if these B cells lack I-E expression. Furthermore, the involvement of either residual transgene expression by B cells or transfer of I-E from DCs to B cells was excluded by the use of mixed bone marrow chimeras. Our results indicate that after priming by DCs in the context of I-E, the MMTV(SIM) Sag can be recognized on the surface of B cells in the context of I-A. The most likely physiological relevance of the lowering of the antigen threshold required for T-cell/B-cell collaboration after DC priming is to allow B cells with a low affinity for antigen to receive T-cell help in a primary immune response. PMID:10482591

Development of a panel of seven duplex real-time PCR assays for detecting 13 streptococcal superantigens.

PubMed

Yang, Peng; Peng, Xiaomin; Cui, Shujuan; Shao, Junbin; Zhu, Xuping; Zhang, Daitao; Liang, Huijie; Wang, Quanyi

2013-07-30

Streptococcal superantigens (SAgs) are the major virulence factors of infection in humans for group A Streptococcus (GAS) bacteria. A panel consisting of seven duplex real-time PCR assays was developed to simultaneously detect 13 streptococcal SAgs and one internal control which may be important in the control of GAS-mediated diseases. Primer and probe sequences were selected based on the highly conserved region from an alignment of nucleotide sequences of the 13 streptococcal SAgs. The reaction conditions of the duplex real-time PCR were optimized and the specificity of the duplex assays was evaluated using SAg positive strains. The limit of detection of the duplex assays was determined by using 10-fold serial dilutions of the DNA of 13 streptococcal SAgs and compared to a conventional polymerase chain reaction (PCR) method for evaluating the duplex assays sensitivity. Using the duplex assays, we were able to differentiate between 13 SAgs from Streptococcus strains and other non-Streptococcus bacteria without cross-reaction. On the other hand, the limit of detection of the duplex assays was at least one or two log dilutions lower than that of the conventional PCR. The panel was highly specific (100%) and the limit of detection of these duplex groups was at least ten times lower than that obtained by using a conventional PCR method.

Single Cells within the Puerto Rico Trench Suggest Hadal Adaptation of Microbial Lineages

PubMed Central

León-Zayas, Rosa; Novotny, Mark; Podell, Sheila; Shepard, Charles M.; Berkenpas, Eric; Nikolenko, Sergey; Pevzner, Pavel; Lasken, Roger S.

2015-01-01

Hadal ecosystems are found at a depth of 6,000 m below sea level and below, occupying less than 1% of the total area of the ocean. The microbial communities and metabolic potential in these ecosystems are largely uncharacterized. Here, we present four single amplified genomes (SAGs) obtained from 8,219 m below the sea surface within the hadal ecosystem of the Puerto Rico Trench (PRT). These SAGs are derived from members of deep-sea clades, including the Thaumarchaeota and SAR11 clade, and two are related to previously isolated piezophilic (high-pressure-adapted) microorganisms. In order to identify genes that might play a role in adaptation to deep-sea environments, comparative analyses were performed with genomes from closely related shallow-water microbes. The archaeal SAG possesses genes associated with mixotrophy, including lipoylation and the glycine cleavage pathway. The SAR11 SAG encodes glycolytic enzymes previously reported to be missing from this abundant and cosmopolitan group. The other SAGs, which are related to piezophilic isolates, possess genes that may supplement energy demands through the oxidation of hydrogen or the reduction of nitrous oxide. We found evidence for potential trench-specific gene distributions, as several SAG genes were observed only in a PRT metagenome and not in shallower deep-sea metagenomes. These results illustrate new ecotype features that might perform important roles in the adaptation of microorganisms to life in hadal environments. PMID:26386059

Antigenic evaluation of a recombinant baculovirus-expressed Sarcocystis neurona SAG1 antigen.

PubMed

Gupta, G D; Lakritz, J; Saville, W J; Livingston, R S; Dubey, J P; Middleton, J R; Marsh, A E

2004-10-01

Sarcocystis neurona is the primary parasite associated with equine protozoal myeloencephalitis (EPM). This is a commonly diagnosed neurological disorder in the Americas that infects the central nervous system of horses. Current serologic assays utilize culture-derived parasites as antigen. This method requires large numbers of parasites to be grown in culture, which is labor intensive and time consuming. Also, a culture-derived whole-parasite preparation contains conserved antigens that could cross-react with antibodies against other Sarcocystis species and members of Sarcocystidae such as Neospora spp., Hammondia spp., and Toxoplasma gondii. Therefore, there is a need to develop an improved method for the detection of S. neurona-specific antibodies. The sera of infected horses react strongly to surface antigen 1 (SnSAG1), an approximately 29-kDa protein, in immunoblot analysis, suggesting that it is an immunodominant antigen. The SnSAG1 gene of S. neurona was cloned, and recombinant S. neurona SAG1 protein (rSnSAG1-Bac) was expressed with the use of a baculovirus system. By immunoblot analysis, the rSnSAG1-Bac antigen detected antibodies to S. neurona from naturally infected and experimentally inoculated equids, cats, rabbit, mice, and skunk. This is the first report of a baculovirus-expressed recombinant S. neurona antigen being used to detect anti-S. neurona antibodies in a variety of host species.

Enamel Hypomineralization in Children With Clefts and the Relationship to Treatment: A Cross-sectional Retrospective Study.

PubMed

Allam, Eman; Ghoneima, Ahmed; Tholpady, Sunil S; Kula, Katherine

2018-06-19

The aim of this study was to determine whether molar incisor hypomineralization (MIH) is greater in patients with cleft lip and palate (CLP) who underwent primary alveolar grafting (PAG) as compared with CLP waiting for secondary alveolar grafting (SAG) and with controls. A retrospective analysis of intraoral photographs of 13 CLP patients who underwent a PAG, 28 CLP prior to SAG, and 60 controls without CLP was performed. Mantel-Haenszel χ tests were used to compare the 3 groups for differences in MIH scores, and Wilcoxon rank sum tests were used to compare the groups for differences in average MIH scores. A 5% significance level was used for all tests. Molar incisor hypomineralization scores were significantly higher for the PAG and SAG groups compared with the control group (P < 0.001). The PAG group had significantly higher incisor MIH (P = 0.016) compared with the SAG group. Molar incisor hypomineralization average scores were significantly higher for the 2 graft groups compared with the controls (P < 0.0001). The PAG group had significantly higher average MIH score and average MIH score for incisors compared with the SAG group (P = 0.03). Cleft lip and palate patients have significantly greater MIH compared with controls, and CLP patients with PAGs have significantly greater MIH in the incisor region compared with CLP patients with SAGs, indicating that subjects with PAGs have more severely affected dentition.

Continentward-dipping detachment fault system and asymmetric rift structure of the Baiyun Sag, northern South China Sea

NASA Astrophysics Data System (ADS)

Zhou, Zhichao; Mei, Lianfu; Liu, Jun; Zheng, Jinyun; Chen, Liang; Hao, Shihao

2018-02-01

The rift architecture and deep crustal structure of the distal margin at the mid-northern margin of the South China Sea have been previously investigated by using deep seismic reflection profiles. However, one fundamental recurring problem in the debate is the extensional fault system and rift structure of the hyperextended rift basins (Baiyun Sag and Liwan Sag) within the distal margin because of the limited amount of seismic data. Based on new 3D seismic survey data and 2D seismic reflection profiles, we observe an array of fault blocks in the Baiyun Sag, which were tilted towards the ocean by extensional faulting. The extensional faults consistently dip towards the continent. Beneath the tilted fault blocks and extensional faults, a low-angle, high-amplitude and continuous reflection has been interpreted as the master detachment surface that controls the extension process. During rifting, the continentward-dipping normal faults evolved in a sequence from south to north, generating the asymmetric rift structure of the Baiyun Sag. The Baiyun Sag is separated from the oceanic domain by a series of structural highs that were uplifted by magmatic activity in response to the continental breakup at 33 Ma and a ridge jump to the south at 26-24 Ma. Therefore, we propose that magmatism played a significant role in the continental extension and final breakup in the South China Sea.

Production of anti-SAG1 IgY antibody against Toxoplasma gondii parasites and evaluation of antibody activity by ELISA method.

PubMed

Cakir-Koc, Rabia

2016-08-01

Chicken egg yolk antibody, also known as immunoglobulin Y (IgY), is the predominant class of serum immunoglobulin in birds. IgY has many advantages over mammalian antibodies, such as enhanced immunogenicity conserved mammalian proteins exhibited in birds due to their phylogenetic distance, non-invasive rapid, and economical collection system. However, there are limited studies about IgY production against Toxoplasma, which is a worldwide veterinary and public health problem. In this study, the production of specific IgY antibodies against the surface antigen 1 (SAG1) protein of Toxoplasma gondii and the determination of antibody activity via the enzyme-linked immunosorbent assay (ELISA) method were conducted. According to ELISA, Western blot, and NanoDrop results, specific and higher amounts of IgY antibody against SAG1 were obtained with this study. Considering the advantages of IgY and importance of SAG1 for the diagnosis of toxoplasmosis, it is expected that anti-SAG1 IgY will play an increasing role and gain commercial value in research, diagnostics, and immunotherapy against toxoplasmosis in the future.

The Development Of New Space Charge Compensation Methods For Multi-Components Ion Beam Extracted From ECR Ion Source at IMP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, L.; Zhao, H.W.; Cao, Y.

2005-03-15

Two new space charge compensation methods developed in IMP are discussed in this paper. There are negative high voltage electrode method (NHVEM) and electronegative charge gas method (EGM). Some valuable experimental data have been achieved, especially using electronegative gas method in O6+ and O7+ dramatic and stable increasing of ion current was observed.

The northern slope of South China Sea: an ideal site for studying passive margin extension and breakup

NASA Astrophysics Data System (ADS)

Zhou, D.; Sun, Z.; Pang, X.; Wu, X.; Xu, H.; Qiu, N.

2011-12-01

With the advance of hydrocarbon exploration into deep waters of the northern SCS, structural details from continental slope to deepsea basin have been revealed. A striking feature is the dramatic change in Cenozoic extension along and across the strike as well as with the time. Along strike the slope is seperated by lithospheric faults into segments with different amount of Cenozoic extension. The breakup occurred in the no-extension eastern segment (the Chaoshan depression), the most strongly extended central segment (the Baiyun sag) but failed in the western segment of intermediate extension (the Qingdongnan basin). This pattern violates the expectation that breakup occurs at first where the extension reached the maximum. In the central segment, the style of extension varies significantly in dip direction. Differing from the belts of half grabens in the shelf, the extension is expressed as a large downwarp (the Baiyun sag) in the slope, and as irregularly shaped sags (the Liwan sag) near the continental-oceanic boundary (COB). The Baiyun sag (BYS) is the largest and deepest sag in the Pearl River Mouth basin (PRMB). Long-cable MCS revealed that at the center of the BYS the crust thinned to <7 km. Grabens and half-grabens are seen only along the SW border of the BYS in Paleogene and did not control the main subsidence of the sag. In Neogene, swarms of NWW-striking small faults developed in the SW and NE flanks of the sag. These features indicate that ductile extension had dominated the formation of the BYS. Suppose the SCS started opening at 30 Ma (although no breakup unconformity found at 30 Ma in the ODP#1148 well adjacent to the COB), the anomalous post-breakup subsidence in the BYS exceeds that predicted by classical model by 1~2 km and occurred most strongly in several periods. Similar anomalous post-breakup subsidence has been observed also in the shelf. The Liwan sag (LWS) SE of the BYS is an aggregate of NS-, NW-, EW-, and NE-elongated narrow and short sags. Its complex shape differs from that of any other sag in the northern SCS, also differs from that of the lower slope of SE Atlantic margin and the Gulf of Mexico where thrust belts developed by gravitational sliding. Multi-staged magmatic activities have contributed to but could not fully explain the structural complexities of the LWS. Perhaps basement structures have played an important role as the sag might be developed upon the relict Mesozoic West Pacific subduction system. In addition, two horizons of deep-seated waving reflectors are identified beneath the LWS, which are suspected to be respectively a detachment surface and the intra-crustal shear zones related to lower-crust flow. A good understanding of these features may help answering the fundamental question on what controls the style, magnitude, and segmentation of passive margin extension and breakup, what is the mechanism, and what differences between marginal sea and open oceans in their evolution and dynamics. Preliminary attempt has been made taking into account basement structure, kinematics of bounding blocks, lithospheric rheology, lower crustal flow, as well as enhanced sediment supply by monsoon strengthening. This study is funded by CNSF40976033.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raj K. Rajamani; Sanjeeva Latchireddi; Sravan K. Prathy

The U.S. mining industry operates approximately 80 semi-autogenesis grinding mills (SAG) throughout the United States. Depending on the mill size the SAG mills draws between 2 MW and 17 MW. The product from the SAG mill is further reduced in size using pebble crushers and ball mills. Hence, typical gold or copper ore requires between 2.0 and 7.5 kWh per ton of energy to reduce the particle size. Considering a typical mining operation processes 10,000 to 100,000 tons per day the energy expenditure in grinding is 50 percent of the cost of production of the metal. A research team frommore » the University of Utah is working to make inroads into saving energy in these SAG mills. In 2003, Industries of the Future Program of the Department of Energy tasked the University of Utah team to build a partnership between the University and the mining industry for the specific purpose of reducing energy consumption in SAG mills. A partnership was formed with Cortez Gold Mines, Kennecott Utah Copper Corporation, Process Engineering Resources Inc. and others. In the current project, Cortez Gold Mines played a key role in facilitating the 26-ft SAG mill at Cortez as a test mill for this study. According to plant personnel, there were a number of unscheduled shut downs to repair broken liners and the mill throughput fluctuated depending on ore type. The University team had two softwares, Millsoft and FlowMod to tackle the problem. Millsoft is capable of simulating the motion of charge in the mill. FlowMod calculates the slurry flow through the grate and pulp lifters. Based on this data the two models were fine-tuned to fit the Cortez SAG will. In the summer of 2004 a new design of shell lifters were presented to Cortez and in September 2004 these lifters were installed in the SAG mill. By December 2004 Cortez Mines realized that the SAG mill is drawing approximately 236-kW less power than before while maintaining the same level of production. In the first month there was extreme cycling and operators had to learn more. Now the power consumption is 0.3-1.3 kWh/ton lower than before. The actual SAG mill power draw is 230-370 kW lower. Mill runs 1 rpm lesser in speed on the average. The re-circulation to the cone crusher is reduced by 1-10%, which means more efficient grinding of critical size material is taking place in the mill. All of the savings have resulted in reduction of operating cost be about $0.023-$0.048/ ton.« less

Power quality control of an autonomous wind-diesel power system based on hybrid intelligent controller.

PubMed

Ko, Hee-Sang; Lee, Kwang Y; Kang, Min-Jae; Kim, Ho-Chan

2008-12-01

Wind power generation is gaining popularity as the power industry in the world is moving toward more liberalized trade of energy along with public concerns of more environmentally friendly mode of electricity generation. The weakness of wind power generation is its dependence on nature-the power output varies in quite a wide range due to the change of wind speed, which is difficult to model and predict. The excess fluctuation of power output and voltages can influence negatively the quality of electricity in the distribution system connected to the wind power generation plant. In this paper, the authors propose an intelligent adaptive system to control the output of a wind power generation plant to maintain the quality of electricity in the distribution system. The target wind generator is a cost-effective induction generator, while the plant is equipped with a small capacity energy storage based on conventional batteries, heater load for co-generation and braking, and a voltage smoothing device such as a static Var compensator (SVC). Fuzzy logic controller provides a flexible controller covering a wide range of energy/voltage compensation. A neural network inverse model is designed to provide compensating control amount for a system. The system can be optimized to cope with the fluctuating market-based electricity price conditions to lower the cost of electricity consumption or to maximize the power sales opportunities from the wind generation plant.

Multilevel cascade voltage source inverter with seperate DC sources

DOEpatents

Peng, Fang Zheng; Lai, Jih-Sheng

1997-01-01

A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.

Multilevel cascade voltage source inverter with seperate DC sources

DOEpatents

Peng, Fang Zheng; Lai, Jih-Sheng

2002-01-01

A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.

Multilevel cascade voltage source inverter with seperate DC sources

DOEpatents

Peng, Fang Zheng; Lai, Jih-Sheng

2001-04-03

A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.

Multilevel cascade voltage source inverter with separate DC sources

DOEpatents

Peng, F.Z.; Lai, J.S.

1997-06-24

A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations. 15 figs.

Flicker Detection, Measurement and Means of Mitigation: A Review

NASA Astrophysics Data System (ADS)

Virulkar, V. B.; Aware, M. V.

2014-04-01

The voltage fluctuations caused by rapid industrial load change have been a major concern for supply utilities, regulatory agencies and customers. This paper gives a general review about how to examine/assess voltage flicker and methods followed in measuring the flickers due to rapid changing loads and means for its mitigation. It discusses the effects on utilities conditions, compensators response time and compensator capacity of flicker mitigation. A comparison between conventional mitigation techniques and the state-of-art mitigation techniques are carried out. It is shown in many cases that the state-of-art solution provides higher performance compared with conventional mitigation techniques. However, the choice of most suitable solution depends on characteristics of the supply at the point of connection, the requirement of the load and economics.

Fatal Toxoplasma gondii infection in the giant panda.

PubMed

Ma, Hongyu; Wang, Zedong; Wang, Chengdong; Li, Caiwu; Wei, Feng; Liu, Quan

2015-01-01

Toxoplasma gondii can infect nearly all warm-blooded animals. We report an acute fatal T. gondii infection in the endangered giant panda (Ailuropoda melanoleuca) in a zoo in China, characterized by acute gastroenteritis and respiratory symptoms. T. gondii infection was confirmed by immunological and molecular methods. Multilocus nested PCR-RFLP revealed clonal type I at the SAG1 and c29-2 loci, clonal type II at the SAG2, BTUB, GRA6, c22-8, and L358 loci, and clonal type III at the alternative SAG2 and SAG3 loci, thus, a potential new genotype of T. gondii in the giant panda. Other possible pathogens were not detected. To our knowledge, this is the first report of clinical toxoplasmosis in a giant panda. © H. Ma et al., published by EDP Sciences, 2015.

Single cells within the Puerto Rico trench suggest hadal adaptation of microbial lineages.

PubMed

León-Zayas, Rosa; Novotny, Mark; Podell, Sheila; Shepard, Charles M; Berkenpas, Eric; Nikolenko, Sergey; Pevzner, Pavel; Lasken, Roger S; Bartlett, Douglas H

2015-12-01

Hadal ecosystems are found at a depth of 6,000 m below sea level and below, occupying less than 1% of the total area of the ocean. The microbial communities and metabolic potential in these ecosystems are largely uncharacterized. Here, we present four single amplified genomes (SAGs) obtained from 8,219 m below the sea surface within the hadal ecosystem of the Puerto Rico Trench (PRT). These SAGs are derived from members of deep-sea clades, including the Thaumarchaeota and SAR11 clade, and two are related to previously isolated piezophilic (high-pressure-adapted) microorganisms. In order to identify genes that might play a role in adaptation to deep-sea environments, comparative analyses were performed with genomes from closely related shallow-water microbes. The archaeal SAG possesses genes associated with mixotrophy, including lipoylation and the glycine cleavage pathway. The SAR11 SAG encodes glycolytic enzymes previously reported to be missing from this abundant and cosmopolitan group. The other SAGs, which are related to piezophilic isolates, possess genes that may supplement energy demands through the oxidation of hydrogen or the reduction of nitrous oxide. We found evidence for potential trench-specific gene distributions, as several SAG genes were observed only in a PRT metagenome and not in shallower deep-sea metagenomes. These results illustrate new ecotype features that might perform important roles in the adaptation of microorganisms to life in hadal environments. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Exposure to Sarcocystis spp. in horses from Spain determined by Western blot analysis using Sarcocystis neurona merozoites as heterologous antigen.

PubMed

Arias, M; Yeargan, M; Francisco, I; Dangoudoubiyam, S; Becerra, P; Francisco, R; Sánchez-Andrade, R; Paz-Silva, A; Howe, D K

2012-04-30

Horses serve as an intermediate host for several species of Sarcocystis, all of which utilize canids as the definitive host. Sarcocystis spp. infection and formation of latent sarcocysts in horses often appears to be subclinical, but morbidity can occur, especially when the parasite burden is large. A serological survey was conducted to determine the presence of antibodies against Sarcocystis spp. in seemingly healthy horses from the Galicia region of Spain. Western blot analyses using Sarcocystis neurona merozoites as heterologous antigen suggested greater than 80% seroprevalance of Sarcocystis spp. in a sample set of 138 horses. The serum samples were further tested with enzyme-linked immunosorbent assays (ELISAs) based on recombinant S. neurona-specific surface antigens (rSnSAGs). As expected for horses from the Eastern Hemisphere, less than 4% of the serum samples were positive when analyzed with either the rSnSAG2 or the rSnSAG4/3 ELISAs. An additional 246 horses were tested using the rSnSAG2 ELISA, which revealed that less than 3% of the 384 samples were seropositive. Collectively, the results of this serologic study suggested that a large proportion of horses from this region of Spain are exposed to Sarcocystis spp. Furthermore, the anti-Sarcocystis seroreactivity in these European horses could be clearly distinguished from anti-S. neurona antibodies using the rSnSAG2 and rSnSAG4/3 ELISAs. Copyright © 2011 Elsevier B.V. All rights reserved.

Compatibility of Automatic Exposure Control with New Screen Phosphors in Diagnostic Roentgenography.

NASA Astrophysics Data System (ADS)

Mulvaney, James Arthur

1982-03-01

Automatic exposure control systems are used in diagnostic roentgenography to obtain proper film density for a variety of patient examinations and roentgenographic techniques. Most automatic exposure control systems have been designed for use with par speed, calcium tungstate intensifying screens. The use of screens with faster speeds and new phosphor materials has put extreme demands on present systems. The performance of a representative automatic exposure control system is investigated to determine its ability to maintain constant film density over a wide range of x-ray tube voltages and acrylic phantom thicknesses with four different intensifying screen phosphors. The effects of x-ray energy dependence, generator switching time and stored change are investigated. The system is able to maintain film density to within plus or minus 0.2 optical density units for techniques representing adult patients. A single nonadjustable tube voltage compensation circuit is adequate for the four different screen phosphors for x-ray tube voltages above sixty peak kilovolts. For techniques representing pediatric patients at high x-ray tube voltages, excess film density occurs due to stored charge in the transformer and high-voltage cables. An anticipation circuit in the automatic exposure control circuit can be modified to correct for stored charge effects. In a separate experiment the energy dependence of three different ionization chamber detectors used in automatic exposure control systems is compared directly with the energy dependence of three different screen phosphors. The data on detector sensitivity and screen speed are combined to predict the best tube voltage compensation for each combination of screen and detector.

Conformational Change in the Active Site of Streptococcal Unsaturated Glucuronyl Hydrolase Through Site-Directed Mutagenesis at Asp-115.

PubMed

Nakamichi, Yusuke; Oiki, Sayoko; Mikami, Bunzo; Murata, Kousaku; Hashimoto, Wataru

2016-08-01

Bacterial unsaturated glucuronyl hydrolase (UGL) degrades unsaturated disaccharides generated from mammalian extracellular matrices, glycosaminoglycans, by polysaccharide lyases. Two Asp residues, Asp-115 and Asp-175 of Streptococcus agalactiae UGL (SagUGL), are completely conserved in other bacterial UGLs, one of which (Asp-175 of SagUGL) acts as a general acid and base catalyst. The other Asp (Asp-115 of SagUGL) also affects the enzyme activity, although its role in the enzyme reaction has not been well understood. Here, we show substitution of Asp-115 in SagUGL with Asn caused a conformational change in the active site. Tertiary structures of SagUGL mutants D115N and D115N/K370S with negligible enzyme activity were determined at 2.00 and 1.79 Å resolution, respectively, by X-ray crystallography. The side chain of Asn-115 is drastically shifted in both mutants owing to the interaction with several residues, including Asp-175, by formation of hydrogen bonds. This interaction between Asn-115 and Asp-175 probably prevents the mutants from triggering the enzyme reaction using Asp-175 as an acid catalyst.

Vertical GaN power diodes with a bilayer edge termination

DOE PAGES

Dickerson, Jeramy R.; Allerman, Andrew A.; Bryant, Benjamin N.; ...

2015-12-07

Vertical GaN power diodes with a bilayer edge termination (ET) are demonstrated. The GaN p-n junction is formed on a low threading dislocation defect density (10 4 - 10 5 cm -2) GaN substrate, and has a 15-μm-thick n-type drift layer with a free carrier concentration of 5 × 10 15 cm -3. The ET structure is formed by N implantation into the p+-GaN epilayer just outside the p-type contact to create compensating defects. The implant defect profile may be approximated by a bilayer structure consisting of a fully compensated layer near the surface, followed by a 90% compensated (p)more » layer near the n-type drift region. These devices exhibit avalanche breakdown as high as 2.6 kV at room temperature. In addition simulations show that the ET created by implantation is an effective way to laterally distribute the electric field over a large area. This increases the voltage at which impact ionization occurs and leads to the observed higher breakdown voltages.« less

Design of a Programmable Gain, Temperature Compensated Current-Input Current-Output CMOS Logarithmic Amplifier.

PubMed

Ming Gu; Chakrabartty, Shantanu

2014-06-01

This paper presents the design of a programmable gain, temperature compensated, current-mode CMOS logarithmic amplifier that can be used for biomedical signal processing. Unlike conventional logarithmic amplifiers that use a transimpedance technique to generate a voltage signal as a logarithmic function of the input current, the proposed approach directly produces a current output as a logarithmic function of the input current. Also, unlike a conventional transimpedance amplifier the gain of the proposed logarithmic amplifier can be programmed using floating-gate trimming circuits. The synthesis of the proposed circuit is based on the Hart's extended translinear principle which involves embedding a floating-voltage source and a linear resistive element within a translinear loop. Temperature compensation is then achieved using a translinear-based resistive cancelation technique. Measured results from prototypes fabricated in a 0.5 μm CMOS process show that the amplifier has an input dynamic range of 120 dB and a temperature sensitivity of 230 ppm/°C (27 °C- 57°C), while consuming less than 100 nW of power.

A High-Temperature Piezoresistive Pressure Sensor with an Integrated Signal-Conditioning Circuit.

PubMed

Yao, Zong; Liang, Ting; Jia, Pinggang; Hong, Yingping; Qi, Lei; Lei, Cheng; Zhang, Bin; Xiong, Jijun

2016-06-18

This paper focuses on the design and fabrication of a high-temperature piezoresistive pressure sensor with an integrated signal-conditioning circuit, which consists of an encapsulated pressure-sensitive chip, a temperature compensation circuit and a signal-conditioning circuit. A silicon on insulation (SOI) material and a standard MEMS process are used in the pressure-sensitive chip fabrication, and high-temperature electronic components are adopted in the temperature-compensation and signal-conditioning circuits. The entire pressure sensor achieves a hermetic seal and can be operated long-term in the range of -50 °C to 220 °C. Unlike traditional pressure sensor output voltage ranges (in the dozens to hundreds of millivolts), the output voltage of this sensor is from 0 V to 5 V, which can significantly improve the signal-to-noise ratio and measurement accuracy in practical applications of long-term transmission based on experimental verification. Furthermore, because this flexible sensor's output voltage is adjustable, general follow-up pressure transmitter devices for voltage converters need not be used, which greatly reduces the cost of the test system. Thus, the proposed high-temperature piezoresistive pressure sensor with an integrated signal-conditioning circuit is expected to be highly applicable to pressure measurements in harsh environments.

A High-Temperature Piezoresistive Pressure Sensor with an Integrated Signal-Conditioning Circuit

PubMed Central

Yao, Zong; Liang, Ting; Jia, Pinggang; Hong, Yingping; Qi, Lei; Lei, Cheng; Zhang, Bin; Xiong, Jijun

2016-01-01

This paper focuses on the design and fabrication of a high-temperature piezoresistive pressure sensor with an integrated signal-conditioning circuit, which consists of an encapsulated pressure-sensitive chip, a temperature compensation circuit and a signal-conditioning circuit. A silicon on insulation (SOI) material and a standard MEMS process are used in the pressure-sensitive chip fabrication, and high-temperature electronic components are adopted in the temperature-compensation and signal-conditioning circuits. The entire pressure sensor achieves a hermetic seal and can be operated long-term in the range of −50 °C to 220 °C. Unlike traditional pressure sensor output voltage ranges (in the dozens to hundreds of millivolts), the output voltage of this sensor is from 0 V to 5 V, which can significantly improve the signal-to-noise ratio and measurement accuracy in practical applications of long-term transmission based on experimental verification. Furthermore, because this flexible sensor’s output voltage is adjustable, general follow-up pressure transmitter devices for voltage converters need not be used, which greatly reduces the cost of the test system. Thus, the proposed high-temperature piezoresistive pressure sensor with an integrated signal-conditioning circuit is expected to be highly applicable to pressure measurements in harsh environments. PMID:27322288

A Transformerless Hybrid Active Filter Capable of Complying with Harmonic Guidelines for Medium-Voltage Motor Drives

NASA Astrophysics Data System (ADS)

Kondo, Ryota; Akagi, Hirofumi

This paper presents a transformerless hybrid active filter that is integrated into medium-voltage adjustable-speed motor drives for fans, pumps, and compressors without regenerative braking. The authors have designed and constructed a three-phase experimental system rated at 400V and 15kW, which is a downscaled model from a feasible 6.6-kV 1-MW motor drive system. This system consists of the hybrid filter connecting a passive filter tuned to the 7th harmonic filter in series with an active filter that is based on a three-level diode-clamped PWM converter, as well as an adjustable-speed motor drive in which a diode rectifier is used as the front end. The hybrid filter is installed on the ac side of the diode rectifier with no line-frequency transformer. The downscaled system has been exclusively tested so as to confirm the overall compensating performance of the hybrid filter and the filtering performance of a switching-ripple filter for mitigating switching-ripple voltages produced by the active filter. Experimental results verify that the hybrid filter achieves harmonic compensation of the source current in all the operating regions from no-load to the rated-load conditions, and that the switching-ripple filter reduces the switching-ripple voltages as expected.

Detection and correction for EPID and gantry sag during arc delivery using cine EPID imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rowshanfarzad, Pejman; Sabet, Mahsheed; O'Connor, Daryl J.

2012-02-15

Purpose: Electronic portal imaging devices (EPIDs) have been studied and used for pretreatment and in-vivo dosimetry applications for many years. The application of EPIDs for dosimetry in arc treatments requires accurate characterization of the mechanical sag of the EPID and gantry during rotation. Several studies have investigated the effects of gravity on the sag of these systems but each have limitations. In this study, an easy experiment setup and accurate algorithm have been introduced to characterize and correct for the effect of EPID and gantry sag during arc delivery. Methods: Three metallic ball bearings were used as markers in themore » beam: two of them fixed to the gantry head and the third positioned at the isocenter. EPID images were acquired during a 360 deg. gantry rotation in cine imaging mode. The markers were tracked in EPID images and a robust in-house developed MATLAB code was used to analyse the images and find the EPID sag in three directions as well as the EPID + gantry sag by comparison to the reference gantry zero image. The algorithm results were then tested against independent methods. The method was applied to compare the effect in clockwise and counter clockwise gantry rotations and different source-to-detector distances (SDDs). The results were monitored for one linear accelerator over a course of 15 months and six other linear-accelerators from two treatment centers were also investigated using this method. The generalized shift patterns were derived from the data and used in an image registration algorithm to correct for the effect of the mechanical sag in the system. The Gamma evaluation (3%, 3 mm) technique was used to investigate the improvement in alignment of cine EPID images of a fixed field, by comparing both individual images and the sum of images in a series with the reference gantry zero image. Results: The mechanical sag during gantry rotation was dependent on the gantry angle and was larger in the in-plane direction, although the patterns were not identical for various linear-accelerators. The reproducibility of measurements was within 0.2 mm over a period of 15 months. The direction of gantry rotation and SDD did not affect the results by more than 0.3 mm. Results of independent tests agreed with the algorithm within the accuracy of the measurement tools. When comparing summed images, the percentage of points with Gamma index <1 increased from 85.4% to 94.1% after correcting for the EPID sag, and to 99.3% after correction for gantry + EPID sag. Conclusions: The measurement method and algorithms introduced in this study use cine-images, are highly accurate, simple, fast, and reproducible. It tests all gantry angles and provides a suitable automatic analysis and correction tool to improve EPID dosimetry and perform comprehensive linac QA for arc treatments.« less

Impact of Clinically Relevant Elliptical Deformations on the Damage Patterns of Sagging and Stretched Leaflets in a Bioprosthetic Heart Valve.

PubMed

Sritharan, Deepa; Fathi, Parinaz; Weaver, Jason D; Retta, Stephen M; Wu, Changfu; Duraiswamy, Nandini

2018-06-12

After implantation of a transcatheter bioprosthetic heart valve its original circular circumference may become distorted, which can lead to changes in leaflet coaptation and leaflets that are stretched or sagging. This may lead to early structural deterioration of the valve as seen in some explanted transcatheter heart valves. Our in vitro study evaluates the effect of leaflet deformations seen in elliptical configurations on the damage patterns of the leaflets, with circular valve deformation as the control. Bovine pericardial tissue heart valves were subjected to accelerated wear testing under both circular (N = 2) and elliptical (N = 4) configurations. The elliptical configurations were created by placing the valve inside custom-made elliptical holders, which caused the leaflets to sag or stretch. The hydrodynamic performance of the valves was monitored and high resolution images were acquired to evaluate leaflet damage patterns over time. In the elliptically deformed valves, sagging leaflets experienced more damage from wear compared to stretched leaflets; the undistorted leaflets of the circular valves experienced the least leaflet damage. Free-edge thinning and tearing were the primary modes of damage in the sagging leaflets. Belly region thinning was seen in the undistorted and stretched leaflets. Leaflet and fabric tears at the commissures were seen in all valve configurations. Free-edge tearing and commissure tears were the leading cause of valve hydrodynamic incompetence. Our study shows that mechanical wear affects heart valve pericardial leaflets differently based on whether they are undistorted, stretched, or sagging in a valve configuration. Sagging leaflets are more likely to be subjected to free-edge tear than stretched or undistorted leaflets. Reducing leaflet stress at the free edge of non-circular valve configurations should be an important factor to consider in the design and/or deployment of transcatheter bioprosthetic heart valves to improve their long-term performance.

Compensation for large thorax excursions in EIT imaging.

PubMed

Schullcke, B; Krueger-Ziolek, S; Gong, B; Mueller-Lisse, U; Moeller, K

2016-09-01

Besides the application of EIT in the intensive care unit it has recently also been used in spontaneously breathing patients suffering from asthma bronchiole, cystic fibrosis (CF) or chronic obstructive pulmonary disease (COPD). In these cases large thorax excursions during deep inspiration, e.g. during lung function testing, lead to artifacts in the reconstructed images. In this paper we introduce a new approach to compensate for image artifacts resulting from excursion induced changes in boundary voltages. It is shown in a simulation study that boundary voltage change due to thorax excursion on a homogeneous model can be used to modify the measured voltages and thus reduce the impact of thorax excursion on the reconstructed images. The applicability of the method on human subjects is demonstrated utilizing a motion-tracking-system. The proposed technique leads to fewer artifacts in the reconstructed images and improves image quality without substantial increase in computational effort, making the approach suitable for real-time imaging of lung ventilation. This might help to establish EIT as a supplemental tool for lung function tests in spontaneously breathing patients to support clinicians in diagnosis and monitoring of disease progression.

Single-virus genomics reveals hidden cosmopolitan and abundant viruses

PubMed Central

Martinez-Hernandez, Francisco; Fornas, Oscar; Lluesma Gomez, Monica; Bolduc, Benjamin; de la Cruz Peña, Maria Jose; Martínez, Joaquín Martínez; Anton, Josefa; Gasol, Josep M.; Rosselli, Riccardo; Rodriguez-Valera, Francisco; Sullivan, Matthew B.; Acinas, Silvia G.; Martinez-Garcia, Manuel

2017-01-01

Microbes drive ecosystems under constraints imposed by viruses. However, a lack of virus genome information hinders our ability to answer fundamental, biological questions concerning microbial communities. Here we apply single-virus genomics (SVGs) to assess whether portions of marine viral communities are missed by current techniques. The majority of the here-identified 44 viral single-amplified genomes (vSAGs) are more abundant in global ocean virome data sets than published metagenome-assembled viral genomes or isolates. This indicates that vSAGs likely best represent the dsDNA viral populations dominating the oceans. Species-specific recruitment patterns and virome simulation data suggest that vSAGs are highly microdiverse and that microdiversity hinders the metagenomic assembly, which could explain why their genomes have not been identified before. Altogether, SVGs enable the discovery of some of the likely most abundant and ecologically relevant marine viral species, such as vSAG 37-F6, which were overlooked by other methodologies. PMID:28643787

Toxoplasma gondii genotypes isolated from pregnant women with follow-up of infected children in southern Brazil.

PubMed

Higa, Lourenço T; Garcia, João L; Su, Chunlei; Rossini, Rita C; Falavigna-Guilherme, Ana L

2014-04-01

Toxoplasma gondii populations that perpetuate in South America's natural ecosystems display broad genetic diversity, but the impact of this diversity on humans is generally unknown. In this short communication, we depict the genotypic traits of four isolates related to congenital parasitism as it emerges in Southern Brazil. Using the PCR-restriction fragment length polymorphism markers SAG1, 5'3'SAG2, alt. SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, Apico, and CS3. Three of the four strains (TgCTBral, TgCTBrv, and TgCTBrac) were identified as ToxoDB genotype #166. Three children displayed normal cognitive/psychomotor development, and one child displayed Sabin's tetrad (TgCTBral). Vertical transmission of the two genotypes was observed and contributes to knowledge of T. gondii strains isolated from humans in Brazil.

Adaptive disturbance compensation finite control set optimal control for PMSM systems based on sliding mode extended state observer

NASA Astrophysics Data System (ADS)

Wu, Yun-jie; Li, Guo-fei

2018-01-01

Based on sliding mode extended state observer (SMESO) technique, an adaptive disturbance compensation finite control set optimal control (FCS-OC) strategy is proposed for permanent magnet synchronous motor (PMSM) system driven by voltage source inverter (VSI). So as to improve robustness of finite control set optimal control strategy, a SMESO is proposed to estimate the output-effect disturbance. The estimated value is fed back to finite control set optimal controller for implementing disturbance compensation. It is indicated through theoretical analysis that the designed SMESO could converge in finite time. The simulation results illustrate that the proposed adaptive disturbance compensation FCS-OC possesses better dynamical response behavior in the presence of disturbance.

Dynamic simulation of Static Var Compensators in distribution systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koessler, R.J.

1992-08-01

This paper is a system study guide for the correction of voltage dips due to large motor startups with Static Var Compensators (SVCs). The method utilizes time simulations, which are an important aid in the equipment design and specification. The paper illustrates the process of setting-up a computer model and performing time simulations. The study process is demonstrated through an example, the Shawnee feeder in the Niagara Mohawk Power Corporation service area.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raj K. Rajamani; Jose Angel Delgadillo

A research team from the University of Utah is working to make inroads into saving energy in these SAG mills. In 2003, Industries of the Future Program of the Department of Energy tasked the University of Utah team to build a partnership between the University and the mining industry for the specific purpose of reducing energy consumption in SAG mills. A partnership was formed with Cortez Gold Mines, Kennecott Utah Copper Corporation, Process Engineering Resources Inc. and Outokumpu Technology. In the current project, Cortez Gold Mines played a key role in facilitating the 26-ft SAG mill at Cortez as amore » test mill for this study. According to plant personnel, there were a number of unscheduled shut downs to repair broken liners and the mill throughput fluctuated depending on ore type. The University team had two softwares, Millsoft and FlowMod to tackle the problem. Millsoft is capable of simulating the motion of charge in the mill. FlowMod calculates the slurry flow through the grate and pulp lifters. Based on this data the two models were fine-tuned to fit the Cortez SAG will. In the summer of 2004 a new design of shell lifters were presented to Cortez and in September 2004 these lifters were installed in the SAG mill. By December 2004 Cortez Mines realized that the SAG mill is drawing approximately 236-kW less power than before while maintaining the same level of production. In the first month there was extreme cycling and operators had to learn more. Now the power consumption is 0.3-1.3 kWh/ton lower than before. The actual SAG mill power draw is 230-370 kW lower. Mill runs 1 rpm lesser in speed on the average. The recirculation to the cone crusher is reduced by 1-10%, which means more efficient grinding of critical size material is taking place in the mill. All of the savings have resulted in reduction of operating cost be about $0.023-$0.048/ ton. After completing the shell lifter design, the pulp lifter design was taken up. Through a series of mill surveys and model calculations it was figured that the radial pulp lifter installed on the mill had less than optimum discharge capacity. A number of alternative designs were evaluated. The final choice was the Turbo Pulp Lifter for which Outukumpu Technology, Centennial, Colorado had filed a patent. After installation of the pulp lifter a 22% increase in throughput rate from 344 stph to 421 stph was realized. A 35% decrease in the SAG mill power draw from 3,908 HP to 2,526 HP (2,915 kW to 1,884 kW) was recorded. This equates to a 47% decrease in SAG unit energy consumption from 8.98 kWh/ton to 4.74 kWh/ton. A 11% decrease in SAG mill speed was observed indicating optimized ball strikes. Also, the ball chip generation from the SAG mill was reduced considerably. Further more, a 7% decrease in ball mill power draw from 4,843 HP to 4,491 HP (3,613 kW to 3,350 kW) was observed. This equates to a 24% decrease in ball mill unit energy consumption from 11.13 kWh/ton to 8.43 kWh/ton.« less

A MPPT Algorithm Based PV System Connected to Single Phase Voltage Controlled Grid

NASA Astrophysics Data System (ADS)

Sreekanth, G.; Narender Reddy, N.; Durga Prasad, A.; Nagendrababu, V.

2012-10-01

Future ancillary services provided by photovoltaic (PV) systems could facilitate their penetration in power systems. In addition, low-power PV systems can be designed to improve the power quality. This paper presents a single-phase PV systemthat provides grid voltage support and compensation of harmonic distortion at the point of common coupling thanks to a repetitive controller. The power provided by the PV panels is controlled by a Maximum Power Point Tracking algorithm based on the incremental conductance method specifically modified to control the phase of the PV inverter voltage. Simulation and experimental results validate the presented solution.

Neurologic Deterioration Due to Brain Sag After Bilateral Craniotomy for Subdural Hematoma Evacuation.

PubMed

Liu, James K C

2018-06-01

Intracranial hypotension from cerebrospinal fluid (CSF) hypovolemia resulting in cerebral herniation is a rare but known complication that can occur after neurosurgical procedures, usually encountered in correlation with perioperative placement of a lumbar subarachnoid drain. Decrease in CSF volume resulting in loss of buoyancy results in downward herniation of the brain without contributing mass effect, causing a phenomenon known as brain sag. Unreported previously is brain sag occurring without concomitant occult CSF leak or lumbar drainage. This case report describes a patient who underwent bilateral craniotomies for subacute on chronic subdural hematoma with successful decompression but experienced acute neurologic deterioration secondary to brain sag. Despite an initial improvement in neurologic function, he subsequently experienced progressive neurologic deterioration with evidence of cerebral herniation on neuroimaging, without evidence of continued mass effect on the brain parenchyma. After a diagnosis of brain sag was determined based on imaging criteria, the patient was placed in a flat position, which resulted in rapid improvement in his neurologic function without any further intervention. This case is unique in comparison with previous reports of intracranial hypotension after craniotomy in that the symptoms were completely reversed with positioning alone, without any evidence of active or occult CSF drainage. This report emphasizes that the diagnosis of brain sag should be taken into consideration when there is an unknown reason for neurologic decline after craniotomy, particularly bilateral craniotomies, if the imaging indicates herniation with imaging findings consistent with intracranial hypotension, without evidence of overlying mass effect. Copyright © 2018 Elsevier Inc. All rights reserved.

Staphylococcal toxic shock syndrome: superantigen-mediated enhancement of endotoxin shock and adaptive immune suppression.

PubMed

Kulhankova, Katarina; King, Jessica; Salgado-Pabón, Wilmara

2014-08-01

Infectious diseases caused by Staphylococcus aureus present a significant clinical and public health problem. S. aureus causes some of the most severe hospital-associated and community-acquired illnesses. Specifically, it is the leading cause of infective endocarditis and osteomyelitis, and the second leading cause of sepsis in the USA. While pathogenesis of S. aureus infections is at the center of current research, many questions remain about the mechanisms underlying staphylococcal toxic shock syndrome (TSS) and associated adaptive immune suppression. Both conditions are mediated by staphylococcal superantigens (SAgs)-secreted staphylococcal toxins that are major S. aureus virulence factors. Toxic shock syndrome toxin-1 (TSST-1) is the SAg responsible for almost all menstrual TSS cases in the USA. TSST-1, staphylococcal enterotoxin B and C are also responsible for most cases of non-menstrual TSS. While SAgs mediate all of the hallmark features of TSS, such as fever, rash, hypotension, and multi-organ dysfunction, they are also capable of enhancing the toxic effects of endogenous endotoxin. This interaction appears to be critical in mediating the severity of TSS and related mortality. In addition, interaction between SAgs and the host immune system has been recognized to result in a unique form of adaptive immune suppression, contributing to poor outcomes of S. aureus infections. Utilizing rabbit models of S. aureus infective endocarditis, pneumonia and sepsis, and molecular genetics techniques, we aim to elucidate the mechanisms of SAg and endotoxin synergism in the pathogenesis of TSS, and examine the cellular and molecular mechanisms underlying SAg-mediated immune dysfunction.

Low Temperature Polycrystalline Silicon Thin Film Transistor Pixel Circuits for Active Matrix Organic Light Emitting Diodes

NASA Astrophysics Data System (ADS)

Fan, Ching-Lin; Lin, Yu-Sheng; Liu, Yan-Wei

A new pixel design and driving method for active matrix organic light emitting diode (AMOLED) displays that use low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs) with a voltage programming method are proposed and verified using the SPICE simulator. We had employed an appropriate TFT model in SPICE simulation to demonstrate the performance of the pixel circuit. The OLED anode voltage variation error rates are below 0.35% under driving TFT threshold voltage deviation (Δ Vth =± 0.33V). The OLED current non-uniformity caused by the OLED threshold voltage degradation (Δ VTO =+0.33V) is significantly reduced (below 6%). The simulation results show that the pixel design can improve the display image non-uniformity by compensating for the threshold voltage deviation in the driving TFT and the OLED threshold voltage degradation at the same time.

Low VOC Barrier Coating for Industrial Maintenance

DTIC Science & Technology

2012-09-01

VOC Total Solids (wt) Total Solids (volume) Percent Pigment Stormer Viscosity Brookfield Viscosity Pot Life Sag Resistance Theoretical...Percent Pigment – Stormer Viscosity – Brookfield Viscosity – Pot Life – Sag Resistance – Theoretical Coverage – Drying Times – Mixing Ratio

Oxygen Sag and Stream Purification.

ERIC Educational Resources Information Center

Neal, Larry; Herwig, Roy

1978-01-01

Presents a literature review of water quality related to oxygen sag and stream purification, covering publications of 1976-77. This review includes: (1) self-purification models; (2) oxygen demand; and (3) reaeration and oxygen transfer. A list of 60 references is also presented. (HM)

MeCorS: Metagenome-enabled error correction of single cell sequencing reads

DOE PAGES

Bremges, Andreas; Singer, Esther; Woyke, Tanja; ...

2016-03-15

Here we present a new tool, MeCorS, to correct chimeric reads and sequencing errors in Illumina data generated from single amplified genomes (SAGs). It uses sequence information derived from accompanying metagenome sequencing to accurately correct errors in SAG reads, even from ultra-low coverage regions. In evaluations on real data, we show that MeCorS outperforms BayesHammer, the most widely used state-of-the-art approach. MeCorS performs particularly well in correcting chimeric reads, which greatly improves both accuracy and contiguity of de novo SAG assemblies.

Characterisation Of Polysacharides And Lipids From Selected Green Algae Species By FTIR-ATR Spectroscopy

NASA Astrophysics Data System (ADS)

Bartošová, Alica; Blinová, Lenka; Gerulová, Kristína

2015-06-01

Fourier transform infrared (FTIR) spectroscopy was used in this study to identify and determine spectral features of Chromochloris zofingiensis (Dönz) Fucíková et L.A. Lewis (SAG 211-14, Gottingen, Germany), Acutodesmus obliguus (Turpin) Hegewald (SAG 276-1, Gottingen, Germany) and Chlorella sorokiniana (K. Brandt) Pröschold et Darienko (SAG 211-40c, Gottingen, Germany). Polysaccharides and lipids from these three algae species were determined using Fourier Transformed Infrared Spectroscopy (FTIR) with ATR accessory with diamante crystal in spectral range from 400 - 4000 cm-1 and resolution 4.

Tissue-associated self-antigens containing exosomes: Role in allograft rejection.

PubMed

Sharma, Monal; Ravichandran, Ranjithkumar; Bansal, Sandhya; Bremner, Ross M; Smith, Michael A; Mohanakumar, T

2018-06-15

Exosomes are extracellular vesicles that express self-antigens (SAgs) and donor human leukocyte antigens. Tissue-specific exosomes can be detected in the circulation following lung, heart, kidney and islet cell transplantations. We collected serum samples from patients who had undergone lung (n = 30), heart (n = 8), or kidney (n = 15) transplantations to isolate circulating exosomes. Exosome purity was analyzed by Western blot, using CD9 exosome-specific markers. Tissue-associated lung SAgs, collagen V (Col-V) and K-alpha 1 tubulin (Kα1T), heart SAgs, myosin and vimentin, and kidney SAgs, fibronectin and collagen IV (Col-IV), were identified using western blot. Lung transplant recipients diagnosed with bronchiolitis obliterans syndrome had exosomes with higher expression of Col-V (4.2-fold) and Kα1T (37.1-fold) than stable. Exosomes isolated from heart transplant recipients diagnosed with coronary artery vasculopathy had a 3.9-fold increase in myosin and a 4.7-fold increase in vimentin compared with stable. Further, Kidney transplant recipients diagnosed with transplant glomerulopathy had circulating exosomes with a 2-fold increased expression of fibronectin and 2.5-fold increase in Col-IV compared with stable. We conclude that circulating exosomes with tissue associated SAgs have the potential to be a noninvasive biomarker for allograft rejection. Copyright © 2018. Published by Elsevier Inc.

Voltage sensing systems and methods for passive compensation of temperature related intrinsic phase shift

DOEpatents

Davidson, James R.; Lassahn, Gordon D.

2001-01-01

A small sized electro-optic voltage sensor capable of accurate measurement of high levels of voltages without contact with a conductor or voltage source is provided. When placed in the presence of an electric field, the sensor receives an input beam of electromagnetic radiation into the sensor. A polarization beam displacer serves as a filter to separate the input beam into two beams with orthogonal linear polarizations. The beam displacer is oriented in such a way as to rotate the linearly polarized beams such that they enter a Pockels crystal at a preferred angle of 45 degrees. The beam displacer is therefore capable of causing a linearly polarized beam to impinge a crystal at a desired angle independent of temperature. The Pockels electro-optic effect induces a differential phase shift on the major and minor axes of the input beam as it travels through the Pockels crystal, which causes the input beam to be elliptically polarized. A reflecting prism redirects the beam back through the crystal and the beam displacer. On the return path, the polarization beam displacer separates the elliptically polarized beam into two output beams of orthogonal linear polarization representing the major and minor axes. In crystals that introduce a phase differential attributable to temperature, a compensating crystal is provided to cancel the effect of temperature on the phase differential of the input beam. The system may include a detector for converting the output beams into electrical signals, and a signal processor for determining the voltage based on an analysis of the output beams. The output beams are amplitude modulated by the frequency of the electric field and the amplitude of the output beams is proportional to the magnitude of the electric field, which is related to the voltage being measured.

A new balancing three level three dimensional space vector modulation strategy for three level neutral point clamped four leg inverter based shunt active power filter controlling by nonlinear back stepping controllers.

PubMed

Chebabhi, Ali; Fellah, Mohammed Karim; Kessal, Abdelhalim; Benkhoris, Mohamed F

2016-07-01

In this paper is proposed a new balancing three-level three dimensional space vector modulation (B3L-3DSVM) strategy which uses a redundant voltage vectors to realize precise control and high-performance for a three phase three-level four-leg neutral point clamped (NPC) inverter based Shunt Active Power Filter (SAPF) for eliminate the source currents harmonics, reduce the magnitude of neutral wire current (eliminate the zero-sequence current produced by single-phase nonlinear loads), and to compensate the reactive power in the three-phase four-wire electrical networks. This strategy is proposed in order to gate switching pulses generation, dc bus voltage capacitors balancing (conserve equal voltage of the two dc bus capacitors), and to switching frequency reduced and fixed of inverter switches in same times. A Nonlinear Back Stepping Controllers (NBSC) are used for regulated the dc bus voltage capacitors and the SAPF injected currents to robustness, stabilizing the system and to improve the response and to eliminate the overshoot and undershoot of traditional PI (Proportional-Integral). Conventional three-level three dimensional space vector modulation (C3L-3DSVM) and B3L-3DSVM are calculated and compared in terms of error between the two dc bus voltage capacitors, SAPF output voltages and THDv, THDi of source currents, magnitude of source neutral wire current, and the reactive power compensation under unbalanced single phase nonlinear loads. The success, robustness, and the effectiveness of the proposed control strategies are demonstrated through simulation using Sim Power Systems and S-Function of MATLAB/SIMULINK. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Three-Level 48-Pulse STATCOM with Pulse Width Modulation

NASA Astrophysics Data System (ADS)

Singh, Bhim; Srinivas, Kadagala Venkata

2016-03-01

In this paper, a new control strategy of a three-level 48-pulse static synchronous compensator (STATCOM) is proposed with a constant dc link voltage and pulse width modulation at fundamental frequency switching. The proposed STATCOM is realized using eight units of three-level voltage source converters (VSCs) to form a three-level 48-pulse STATCOM. The conduction angle of each three-level VSC is modulated to control the ac converter output voltage, which controls the reactive power of the STATCOM. A fuzzy logic controller is used to control the STATCOM. The dynamic performance of the STATCOM is studied for the control of the reference reactive power, the reference terminal voltage and under the switching of inductive and capacitive loads.

Effects of voltage control in utility interactive dispersed storage and generation systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kirkham, H.; Das, R.

1983-03-15

When a small generator is connected to the distribution system, the voltage at the point of interconnection is determined largely by the system and not the generator. This report examines the effect on the generator, on the load voltage and on the distribution system of a number of different voltage control strategies in the generator. Synchronous generators with three kinds of exciter control are considered, as well as induction generators and dc/ac inverters, with and without capacitor compensation. The effect of varying input power during operation (which may be experienced by generators based on renewable resources) is explored, as wellmore » as the effect of connecting and disconnecting the generator at ten percent of its rated power.« less

Accurate antemortem diagnosis of equine protozoal myeloencephalitis (EPM) based on detecting intrathecal antibodies against Sarcocystis neurona using the SnSAG2 and SnSAG4/3 ELISAs.

PubMed

Reed, S M; Howe, D K; Morrow, J K; Graves, A; Yeargan, M R; Johnson, A L; MacKay, R J; Furr, M; Saville, W J A; Williams, N M

2013-01-01

Recent work demonstrated the value of antigen-specific antibody indices (AI and C-value) to detect intrathecal antibody production against Sarcocystis neurona for antemortem diagnosis of equine protozoal myeloencephalitis (EPM). The study was conducted to assess whether the antigen-specific antibody indices can be reduced to a simple serum : cerebrospinal fluid (CSF) titer ratio to achieve accurate EPM diagnosis. Paired serum and CSF samples from 128 horses diagnosed by postmortem examination. The sample set included 44 EPM cases, 35 cervical-vertebral malformation (CVM) cases, 39 neurologic cases other than EPM or CVM, and 10 non-neurologic cases. Antibodies against S. neurona were measured in serum and CSF pairs using the SnSAG2 and SnSAG4/3 (SnSAG2, 4/3) ELISAs, and the ratio of each respective serum titer to CSF titer was determined. Likelihood ratios and diagnostic sensitivity and specificity were calculated based on serum titers, CSF titers, and serum : CSF titer ratios. Excellent diagnostic sensitivity and specificity was obtained from the SnSAG2, 4/3 serum : CSF titer ratio. Sensitivity and specificity of 93.2 and 81.1%, respectively, were achieved using a ratio cutoff of ≤100, whereas sensitivity and specificity were 86.4 and 95.9%, respectively, if a more rigorous cutoff of ≤50 was used. Antibody titers in CSF also provided good diagnostic accuracy. Serum antibody titers alone yielded much lower sensitivity and specificity. The study confirms the value of detecting intrathecal antibody production for antemortem diagnosis of EPM, and they further show that the antigen-specific antibody indices can be reduced in practice to a simple serum : CSF titer ratio. Copyright © 2013 by the American College of Veterinary Internal Medicine.

Episodic normal faulting and magmatism during the syn-spreading stage of the Baiyun sag in Pearl River Mouth Basin: response to the multi-phase seafloor spreading of the South China Sea

NASA Astrophysics Data System (ADS)

Deng, Peng; Mei, Lianfu; Liu, Jun; Zheng, Jinyun; Liu, Minghui; Cheng, Zijie; Guo, Fengtai

2018-03-01

Considerable post-breakup extensional deformation is recorded in the continental margins of the South China Sea (SCS). To recognize the nature and origin of the significant deformation during the syn-spreading stage (32-15.5 Ma) in the SCS, we comprehensively analyzed the geometry and kinematics of the faults and contemporaneous magmas in the Baiyun sag, northern margin of the SCS, using high-resolution regional three-dimensional seismic data. The kinematic analyses indicate that the faults in the Baiyun sag are recently formed following the onset of seafloor spreading in the SCS. The faults exhibit multiple episodes of growth history, with three active episodes, 32-29, 23.8-21 and 18.5-16.5 Ma, separated by periods of inactivity. Four volcanic groups comprising 98 volcanic mounds have been identified and described, located separately in the northwestern, the central, the southeastern and the northern slope areas. The occurrence of multiple palaeo-seafloors, complemented by the biostratigraphic and K-Ar dating data, reveals multiple extrusive events of the syn-spreading magmas in the Baiyun sag, with three active periods of 23.8-21, 18.5-17.5 and 17.5-16.5 Ma. This study confirms that the normal faulting has a shared genetic origin with the contemporaneous magmatism during the syn-spreading stage in the deep-offshore Baiyun sag, northern margin of the SCS. The episodic fault growth and magmatic extrusive events reveal that the Baiyun sag has undergone at least three episodic tectonic events during the syn-spreading stage, which evolved in response to the multi-stage seafloor spreading of the SCS.

Prospective evaluation of the Sunshine Appendicitis Grading System score.

PubMed

Reid, Fiona; Choi, Julian; Williams, Marli; Chan, Steven

2017-05-01

Although there is a wealth of information predicting risk of post-operative intra-abdominal collection and guiding antibiotic therapy following appendicectomy, confusion remains because of lack of consensus on the clinical severity and definition of 'complicated' appendicitis. This study aimed to develop a standardized intra-operative grading system: Sunshine Appendicitis Grading System (SAGS) for acute appendicitis that correlates independently with the risk of intra-abdominal collections. Two-hundred and forty-six patients undergoing emergency laparoscopy for suspected appendicitis were prospectively scored according to the severity of appendicitis and followed up for complications including intra-abdominal collection. After termination of the study, the SAGS score was repeated by an independent surgeon based on operation notes and intra-operative photography to determine inter-rater agreement. The primary outcome measure was incidence of intra-abdominal collection, secondary outcome measures were all complications and length of stay. SAGS score demonstrated good inter-rater agreement (kappa K w 0.869; 95% CI 0.796-0.941; P < 0.001). A risk ratio of 2.594 (95% CI 0.655-4.065; P < 0.001) for intra-abdominal collection was found using SAGS score as a predictor. The discriminative ability of SAGS score was supported by an area under the curve value of 0.850 (95% CI 0.799-0.892; P < 0.001). SAGS score can be used to simply and accurately classify the severity of appendicitis and to independently predict the risk of intra-abdominal collection. It can therefore be used to stratify risk, guide antibiotic therapy, follow-up and standardize the definitions of appendicitis severity for future research. © 2015 Royal Australasian College of Surgeons.

Acute upregulation of hedgehog signaling in mice causes differential effects on cranial morphology.

PubMed

Singh, Nandini; Dutka, Tara; Devenney, Benjamin M; Kawasaki, Kazuhiko; Reeves, Roger H; Richtsmeier, Joan T

2015-03-01

Hedgehog (HH) signaling, and particularly signaling by sonic hedgehog (SHH), is implicated in several essential activities during morphogenesis, and its misexpression causes a number of developmental disorders in humans. In particular, a reduced mitogenic response of cerebellar granule cell precursors to SHH signaling in a mouse model for Down syndrome (DS), Ts65Dn, is substantially responsible for reduced cerebellar size. A single treatment of newborn trisomic mice with an agonist of the SHH pathway (SAG) normalizes cerebellar morphology and restores some cognitive deficits, suggesting a possible therapeutic application of SAG for treating the cognitive impairments of DS. Although the beneficial effects on the cerebellum are compelling, inappropriate activation of the HH pathway causes anomalies elsewhere in the head, particularly in the formation and patterning of the craniofacial skeleton. To determine whether an acute treatment of SAG has an effect on craniofacial morphology, we quantitatively analyzed the cranial form of adult euploid and Ts65Dn mice that were injected with either SAG or vehicle at birth. We found significant deformation of adult craniofacial shape in some animals that had received SAG at birth. The most pronounced differences between the treated and untreated mice were in the midline structures of the facial skeleton. The SAG-driven craniofacial dysmorphogenesis was dose-dependent and possibly incompletely penetrant at lower concentrations. Our findings illustrate that activation of HH signaling, even with an acute postnatal stimulation, can lead to localized dysmorphology of the skull by generating modular shape changes in the facial skeleton. These observations have important implications for translating HH-agonist-based treatments for DS. © 2015. Published by The Company of Biologists Ltd.

Methods of operation of apparatus measuring formation resistivity from within a cased well having one measurement and two compensation steps

DOEpatents

Vail, III, William B.

1993-01-01

Methods of operation of an apparatus having at least two pairs of voltage measurement electrodes vertically disposed in a cased well to measure the resistivity of adjacent geological formations from inside the cased well. During stationary measurements with the apparatus at a fixed vertical depth within the cased well, the invention herein discloses methods of operation which include a measurement step and subsequent first and second compensation steps respectively resulting in improved accuracy of measurement. First and second order errors of measurement are identified, and the measurement step and two compensation steps provide methods to substantially eliminate their influence on the results. A multiple frequency apparatus adapted to movement within the well is described which simultaneously provide the measurement and two compensation steps.

SEMICONDUCTOR TECHNOLOGY: An efficient dose-compensation method for proximity effect correction

NASA Astrophysics Data System (ADS)

Ying, Wang; Weihua, Han; Xiang, Yang; Renping, Zhang; Yang, Zhang; Fuhua, Yang

2010-08-01

A novel simple dose-compensation method is developed for proximity effect correction in electron-beam lithography. The sizes of exposed patterns depend on dose factors while other exposure parameters (including accelerate voltage, resist thickness, exposing step size, substrate material, and so on) remain constant. This method is based on two reasonable assumptions in the evaluation of the compensated dose factor: one is that the relation between dose factors and circle-diameters is linear in the range under consideration; the other is that the compensated dose factor is only affected by the nearest neighbors for simplicity. Four-layer-hexagon photonic crystal structures were fabricated as test patterns to demonstrate this method. Compared to the uncorrected structures, the homogeneity of the corrected hole-size in photonic crystal structures was clearly improved.

Screening and identification of novel B cell epitopes of Toxoplasma gondii SAG1.

PubMed

Wang, Yanhua; Wang, Guangxiang; Zhang, Delin; Yin, Hong; Wang, Meng

2013-04-30

The identification of protein epitopes is useful for diagnostic purposes and for the development of peptide vaccines. In this study, the epitopes of Toxoplasma gondii SAG1 were identified using synthetic peptide techniques with the aid of bioinformatics. Eleven peptides derived from T. gondii SAG1 were assessed by ELISA using pig sera from different time points after infection. Four (PS4, PS6, PS10 and PS11), out of the eleven peptides tested were recognized by all sera. Then, shorter peptides that were derived from PS4, PS6, PS10 and PS11 were predicted using bioinformatics and tested by experimentation. Four out of nine shorter peptides were identified successfully (amino acids 106-120, 166-180, 289-300 and 313-332). We have precisely located the epitopes of T. gondii SAG1 using pig sera collected at different time points after infection. The identified epitopes may be useful for the further study of epitope-based vaccines and diagnostic reagents.

Single-virus genomics reveals hidden cosmopolitan and abundant viruses

DOE PAGES

Martinez-Hernandez, Francisco; Fornas, Oscar; Lluesma Gomez, Monica; ...

2017-06-23

Microbes drive ecosystems under constraints imposed by viruses. However, a lack of virus genome information hinders our ability to answer fundamental, biological questions concerning microbial communities. Here we apply single-virus genomics (SVGs) to assess whether portions of marine viral communities are missed by current techniques. The majority of the here-identified 44 viral single-amplified genomes (vSAGs) are more abundant in global ocean virome data sets than published metagenome-assembled viral genomes or isolates. This indicates that vSAGs likely best represent the dsDNA viral populations dominating the oceans. Species-specific recruitment patterns and virome simulation data suggest that vSAGs are highly microdiverse and thatmore » microdiversity hinders the metagenomic assembly, which could explain why their genomes have not been identified before. Altogether, SVGs enable the discovery of some of the likely most abundant and ecologically relevant marine viral species, such as vSAG 37-F6, which were overlooked by other methodologies.« less

Single-virus genomics reveals hidden cosmopolitan and abundant viruses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martinez-Hernandez, Francisco; Fornas, Oscar; Lluesma Gomez, Monica

Microbes drive ecosystems under constraints imposed by viruses. However, a lack of virus genome information hinders our ability to answer fundamental, biological questions concerning microbial communities. Here we apply single-virus genomics (SVGs) to assess whether portions of marine viral communities are missed by current techniques. The majority of the here-identified 44 viral single-amplified genomes (vSAGs) are more abundant in global ocean virome data sets than published metagenome-assembled viral genomes or isolates. This indicates that vSAGs likely best represent the dsDNA viral populations dominating the oceans. Species-specific recruitment patterns and virome simulation data suggest that vSAGs are highly microdiverse and thatmore » microdiversity hinders the metagenomic assembly, which could explain why their genomes have not been identified before. Altogether, SVGs enable the discovery of some of the likely most abundant and ecologically relevant marine viral species, such as vSAG 37-F6, which were overlooked by other methodologies.« less

First report of genotype #65 of Toxoplasma gondii in pigs.

PubMed

Samico-Fernandes, Erika Fernanda Torres; de Melo, Renata Pimentel Bandeira; de Cássia Peixoto Kim, Pomy; de Almeida, Jonatas Campos; de Barros, Luiz Daniel; Garcia, João Luis; da Silva, Jean Carlos Ramos; Mota, Rinaldo Aparecido

2015-10-01

The aim of the present study was to isolate and genotype Toxoplasma gondii from pigs slaughtered for human consumption in northeastern Brazil. Indirect immunofluorescence antibody test (IFAT) was used to screen positive pigs. Tissues samples of animals with antibody titers ≥64 were submitted to bioassay in mice. One isolate of T. gondii was obtained, and the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique, using 11 markers (SAG1, SAG2, altSAG2, SAG3, BTUB, GRA6, c228, c292, L358, PK1, and APICO), was applied to evaluate the genetic variability. DNA from reference strains was used as a positive control. By means of genetic analysis, genotype ToxoDB #65 was identified, which is considered an atypical strain. This is the first record of genotype #65 in pigs. Thus, further studies in this region are necessary to determine the genetic variability of T. gondii in pigs and possible impact on public health.

Frequency Invariability of (Pb,La)(Zr,Ti)O₃ Antiferroelectric Thick-Film Micro-Cantilevers.

PubMed

An, Kun; Jin, Xuechen; Meng, Jiang; Li, Xiao; Ren, Yifeng

2018-05-13

Micro-electromechanical systems comprising antiferroelectric layers can offer both actuation and transduction to integrated technologies. Micro-cantilevers based on the (Pb 0.97 La 0.02 )(Zr 0.95 Ti 0.05 )O₃ (PLZT) antiferroelectric thick film are fabricated by the micro-nano manufacturing process, to utilize the effect of phase transition induced strain and sharp phase switch of antiferroelectric materials. When micro-cantilevers made of antiferroelectric thick films were driven by sweep voltages, there were two resonant peaks corresponding to the natural frequency shift from 27.8 to 27.0 kHz, before and after phase transition. This is the compensation principle for the PLZT micro-cantilever to tune the natural frequency by the amplitude modulation of driving voltage, rather than of frequency modulation. Considering the natural frequency shift about 0.8 kHz and the frequency tuning ability about 156 Hz/V before the phase transition, this can compensate the frequency shift caused by increasing temperature by tuning only the amplitude of driving voltage, when the ultrasonic micro-transducer made of antiferroelectric thick films works for such a long period. Therefore, antiferroelectric thick films with hetero-structures incorporated into PLZT micro-cantilevers not only require a lower driving voltage (no more than 40 V) than rival bulk piezoelectric ceramics, but also exhibit better performance of frequency invariability, based on the amplitude modulation.

Superantigens are critical for Staphylococcus aureus Infective endocarditis, sepsis, and acute kidney injury.

PubMed

Salgado-Pabón, Wilmara; Breshears, Laura; Spaulding, Adam R; Merriman, Joseph A; Stach, Christopher S; Horswill, Alexander R; Peterson, Marnie L; Schlievert, Patrick M

2013-08-20

Infective endocarditis and kidney infections are serious complications of Staphylococcus aureus sepsis. We investigated the role of superantigens (SAgs) in the development of lethal sepsis, infective endocarditis, and kidney infections. SAgs cause toxic shock syndrome, but it is unclear if SAgs contribute to infective endocarditis and kidney infections secondary to sepsis. We show in the methicillin-resistant S. aureus strain MW2 that lethal sepsis, infective endocarditis, and kidney infections in rabbits are critically dependent on high-level SAgs. In contrast, the isogenic strain lacking staphylococcal enterotoxin C (SEC), the major SAg in this strain, is attenuated in virulence, while complementation restores disease production. SAgs' role in infective endocarditis appears to be both superantigenicity and direct endothelial cell stimulation. Maintenance of elevated blood pressure by fluid therapy significantly protects from infective endocarditis, possibly through preventing bacterial accumulation on valves and increased SAg elimination. These data should facilitate better methods to manage these serious illnesses. The Centers for Disease Control and Prevention reported in 2007 that Staphylococcus aureus is the most significant cause of serious infectious diseases in the United States (R. M. Klevens, M. A. Morrison, J. Nadle, S. Petit, K. Gershman, et al., JAMA 298:1763-1771, 2007). Among these infections are sepsis, infective endocarditis, and acute kidney injury. Infective endocarditis occurs in 30 to 60% of patients with S. aureus bacteremia and carries a mortality rate of 40 to 50%. Over the past decades, infective endocarditis outcomes have not improved, and infection rates are steadily increasing (D. H. Bor, S. Woolhandler, R. Nardin, J. Brusch, D. U. Himmelstein, PLoS One 8:e60033, 2013). There is little understanding of the S. aureus virulence factors that are key for infective endocarditis development and kidney abscess formation. We demonstrate that superantigens are critical in the causation of all three infections. We show that their association results from both superantigenicity and direct toxic effects on endothelial cells, the latter likely contributing to delayed endothelium healing. Our studies contribute significantly to understanding the development of these illnesses and are expected to lead to development of important therapies to treat such illnesses.

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. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Discovery of a photoresponse amplification mechanism in compensated PN junctions

NASA Astrophysics Data System (ADS)

Zhou, Yuchun; Liu, Yu-Hsin; Rahman, Samia N.; Hall, David; Sham, L. J.; Lo, Yu-Hwa

2015-01-01

We report the experimental evidence of uncovering a photoresponse amplification mechanism in heavily doped, partially compensated silicon p-n junctions under very low bias voltage. We show that the observed photocurrent gain occurs at a bias that is more than an order of magnitude below the threshold voltage for conventional impact ionization. Moreover, contrary to the case of avalanche detectors and p-i-n diodes, the amplified photoresponse is enhanced rather than suppressed with increasing temperature. These distinctive characteristics lead us to hypothesize that the inelastic scattering between energetic electrons (holes) and the ionized impurities in the depletion and charge neutral regions of the p-n junction in a cyclic manner plays a significant role in the amplification process. Such an internal signal amplification mechanism, which occurs at much lower bias than impact ionization and favors room temperature over cryogenic temperature, makes it promising for practical device applications.

Discovery of a photoresponse amplification mechanism in compensated PN junctions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Yuchun; Rahman, Samia N.; Hall, David

2015-01-19

We report the experimental evidence of uncovering a photoresponse amplification mechanism in heavily doped, partially compensated silicon p-n junctions under very low bias voltage. We show that the observed photocurrent gain occurs at a bias that is more than an order of magnitude below the threshold voltage for conventional impact ionization. Moreover, contrary to the case of avalanche detectors and p-i-n diodes, the amplified photoresponse is enhanced rather than suppressed with increasing temperature. These distinctive characteristics lead us to hypothesize that the inelastic scattering between energetic electrons (holes) and the ionized impurities in the depletion and charge neutral regions ofmore » the p-n junction in a cyclic manner plays a significant role in the amplification process. Such an internal signal amplification mechanism, which occurs at much lower bias than impact ionization and favors room temperature over cryogenic temperature, makes it promising for practical device applications.« less

Fiber-coupled LED gas sensor and its application to online monitoring of ecoefficient dielectric insulation gases in high-voltage circuit breakers.

PubMed

Kramer, Axel; Over, Daniel; Stoller, Patrick; Paul, Thomas A

2017-05-20

Novel dielectric insulation gases used as alternatives to sulfur hexafluoride in gas-insulated switchgear (GIS) include several mixtures containing fluorinated organic compounds. We developed a fiber-optic analyzer enabling concentration measurement of fluoroketones used in medium- and high-voltage switchgear applications by ABB, with concurrent compensation of disturbing effects caused by dust and dirt. The sensor enables measurements in GIS and even in operating high-voltage circuit breakers. The online availability of concentration readings of fluoroketones is important for development tests, but can also be applied for monitoring or diagnostics of field installations.

Measuring bi-directional current through a field-effect transistor by virtue of drain-to-source voltage measurement

DOEpatents

Turner, Steven Richard

2006-12-26

A method and apparatus for measuring current, and particularly bi-directional current, in a field-effect transistor (FET) using drain-to-source voltage measurements. The drain-to-source voltage of the FET is measured and amplified. This signal is then compensated for variations in the temperature of the FET, which affects the impedance of the FET when it is switched on. The output is a signal representative of the direction of the flow of current through the field-effect transistor and the level of the current through the field-effect transistor. Preferably, the measurement only occurs when the FET is switched on.

A new AC driving circuit for a top emission AMOLED

NASA Astrophysics Data System (ADS)

Yongwen, Zhang; Wenbin, Chen; Haohan, Liu

2013-05-01

A new voltage programmed pixel circuit with top emission design for active-matrix organic light-emitting diode (AMOLED) displays is presented and verified by HSPICE simulations. The proposed pixel circuit consists of five poly-Si TFTs, and can effectively compensate for the threshold voltage variation of the driving TFT. Meanwhile, the proposed pixel circuit offers an AC driving mode for the OLED by the two adjacent pulse voltage sources, which can suppress the degradation of the OLED. Moreover, a high contrast ratio can be achieved by the proposed pixel circuit since the OLED does not emit any light except for the emission period.

Publications - GMC 157 | Alaska Division of Geological & Geophysical

Science.gov Websites

chromatograms of core from the Sag Delta 34633 #4 well (11,637'-12,129') and from OCS Y-0197 (Tern #3) well , and whole oil chromatograms of core from the Sag Delta 34633 #4 well (11,637'-12,129') and from OCS Y

Distinct SagA from Hospital-Associated Clade A1 Enterococcus faecium Strains Contributes to Biofilm Formation

PubMed Central

Paganelli, F. L.; de Been, M.; Braat, J. C.; Hoogenboezem, T.; Vink, C.; Bayjanov, J.; Rogers, M. R. C.; Huebner, J.; Bonten, M. J. M.; Willems, R. J. L.

2015-01-01

Enterococcus faecium is an important nosocomial pathogen causing biofilm-mediated infections. Elucidation of E. faecium biofilm pathogenesis is pivotal for the development of new strategies to treat these infections. In several bacteria, extracellular DNA (eDNA) and proteins act as matrix components contributing to biofilm development. In this study, we investigated biofilm formation capacity and the roles of eDNA and secreted proteins for 83 E. faecium strains with different phylogenetic origins that clustered in clade A1 and clade B. Although there was no significant difference in biofilm formation between E. faecium strains from these two clades, the addition of DNase I or proteinase K to biofilms demonstrated that eDNA is essential for biofilm formation in most E. faecium strains, whereas proteolysis impacted primarily biofilms of E. faecium clade A1 strains. Secreted antigen A (SagA) was the most abundant protein in biofilms from E. faecium clade A1 and B strains, although its localization differed between the two groups. sagA was present in all sequenced E. faecium strains, with a consistent difference in the repeat region between the clades, which correlated with the susceptibility of biofilms to proteinase K. This indicates an association between the SagA variable repeat profile and the localization and contribution of SagA in E. faecium biofilms. PMID:26209668

Distinct SagA from Hospital-Associated Clade A1 Enterococcus faecium Strains Contributes to Biofilm Formation.

PubMed

Paganelli, F L; de Been, M; Braat, J C; Hoogenboezem, T; Vink, C; Bayjanov, J; Rogers, M R C; Huebner, J; Bonten, M J M; Willems, R J L; Leavis, H L

2015-10-01

Enterococcus faecium is an important nosocomial pathogen causing biofilm-mediated infections. Elucidation of E. faecium biofilm pathogenesis is pivotal for the development of new strategies to treat these infections. In several bacteria, extracellular DNA (eDNA) and proteins act as matrix components contributing to biofilm development. In this study, we investigated biofilm formation capacity and the roles of eDNA and secreted proteins for 83 E. faecium strains with different phylogenetic origins that clustered in clade A1 and clade B. Although there was no significant difference in biofilm formation between E. faecium strains from these two clades, the addition of DNase I or proteinase K to biofilms demonstrated that eDNA is essential for biofilm formation in most E. faecium strains, whereas proteolysis impacted primarily biofilms of E. faecium clade A1 strains. Secreted antigen A (SagA) was the most abundant protein in biofilms from E. faecium clade A1 and B strains, although its localization differed between the two groups. sagA was present in all sequenced E. faecium strains, with a consistent difference in the repeat region between the clades, which correlated with the susceptibility of biofilms to proteinase K. This indicates an association between the SagA variable repeat profile and the localization and contribution of SagA in E. faecium biofilms. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Early Increases in Superantigen-Specific Foxp3+ Regulatory T Cells during Mouse Mammary Tumor Virus Infection▿ †

PubMed Central

Cabrera, Gabriel; Burzyn, Dalia; Mundiñano, Juliana; Courreges, M. Cecilia; Camicia, Gabriela; Lorenzo, Daniela; Costa, Héctor; Ross, Susan R.; Nepomnaschy, Irene; Piazzon, Isabel

2008-01-01

Mouse mammary tumor virus (MMTV) is a milk-borne betaretrovirus that has developed strategies to exploit and subvert the host immune system. Here, we show in a natural model of MMTV infection that the virus causes early and progressive increases in superantigen (SAg)-specific Foxp3+ regulatory T cells (Treg) in Peyer's patches (PP). These increases were shown to be dependent on the presence of dendritic cells. CD4+ CD25+ T cells from the PP of infected mice preferentially suppress the proliferative response of T cells to SAg-expressing antigen-presenting cells ex vivo. We investigated the influence of the depletion of CD25+ cells at different stages of the infection. When CD25+ cells were depleted before MMTV infection, an increase in the number of PP SAg-cognate Foxp3− T cells was found at day 6 of infection. Since the SAg response is associated with viral amplification, the possibility exists that Treg cells attenuate the increase in viral load at the beginning of the infection. In contrast, depletion of CD25+ cells once the initial SAg response has developed caused a lower viral load, suggesting that at later stages Treg cells may favor viral persistence. Thus, our results indicated that Treg cells play an important and complex role during MMTV infection. PMID:18495774

BILATERAL RETINOCHOROIDITIS CAUSED BY AN ATYPICAL STRAIN OF TOXOPLASMA GONDII

PubMed Central

Bottós, Juliana; Miller, Robin H.; Belfort, Rubens N.; Macedo, Ana Carolina; Belfort, Rubens; Grigg, Michael E.

2012-01-01

Background A 53-year-old man presented with an acute bilateral posterior uveitis with extensive necrotizing retinochoroiditis but without chorioretinal scarring. A thorough workup did not reveal any underlying disease. The possibilities of atypical ocular toxoplasmosis as well as herpetic retinal necrosis were considered and specific therapy instituted, with little improvement. The patient died within two months as result of an undifferentiated squamous cell carcinoma. Methods Histopathological examination, immunohistochemistry and multi-locus polymerase chain reaction confirmed T. gondii infection of the retina Results Macroscopic examination of enucleated globe showed extensive retinal necrosis and vitreous detachment. Histological examination of retinal tissue identified numerous round–to-elliptical toxoplasmic cysts within the retina, with retinal necrosis and minimal choroidal inflammation. Immunohistochemical analyses confirmed the cysts were due to Toxoplasma gondii. DNA extracted from formalin-fixed, paraffin-embedded tissue sections was subjected to multi-locus PCR analysis at the following typing loci: SAG1, SAG2, SAG3, SAG4, B1, NTS2, GRA6, and GRA7. DNA sequencing of positive PCR products at the NTS2, SAG1, and GRA7 loci confirmed the presence of a non-archetypal strain of T. gondii infecting the eye of the patient experiencing a severe, atypical ocular toxoplasmosis Conclusion A highly divergent, non-archetypal strain of Toxoplasma gondii was responsible for causing a severe, atypical bilateral retinochoroiditis in a patient from Brazil. PMID:19666926

Mechanism of H₂ histamine receptor dependent modulation of body temperature and neuronal activity in the medial preoptic nucleus.

PubMed

Tabarean, Iustin V; Sanchez-Alavez, Manuel; Sethi, Jasmine

2012-08-01

Histamine is involved in the central control of arousal, circadian rhythms and metabolism. The preoptic area, a region that contains thermoregulatory neurons is the main locus of histamine modulation of body temperature. Here we report that in mice, histamine activates H(2) subtype receptors in the medial preoptic nucleus (MPON) and induces hyperthermia. We also found that a population of glutamatergic MPON neurons express H(2) receptors and are excited by histamine or H(2) specific agonists. The agonists decreased the input resistance of the neuron and increased the depolarizing "sag" observed during hyperpolarizing current injections. Furthermore, at -60 mV holding potential, activation of H(2) receptors induced an inward current that was blocked by ZD7288, a specific blocker of the hyperpolarization activated cationic current (I(h)). Indeed, activation of H(2) receptors resulted in increased I(h) amplitude in response to hyperpolarizing voltage steps and a depolarizing shift in its voltage-dependent activation. The neurons excited by H(2) specific agonism expressed the HCN1 and HCN2 channel subunits. Our data indicate that at the level of the MPON histamine influences thermoregulation by increasing the firing rate of glutamatergic neurons that express H(2) receptors. Copyright © 2012 Elsevier Ltd. All rights reserved.

MAIT cells launch a rapid, robust and distinct hyperinflammatory response to bacterial superantigens and quickly acquire an anergic phenotype that impedes their cognate antimicrobial function: Defining a novel mechanism of superantigen-induced immunopathology and immunosuppression

PubMed Central

Shaler, Christopher R.; Choi, Joshua; Rudak, Patrick T.; Memarnejadian, Arash; Szabo, Peter A.; Tun-Abraham, Mauro E.; Rossjohn, Jamie; Corbett, Alexandra J.; McCluskey, James; McCormick, John K.; Lantz, Olivier; Hernandez-Alejandro, Roberto; Haeryfar, S.M. Mansour

2017-01-01

Superantigens (SAgs) are potent exotoxins secreted by Staphylococcus aureus and Streptococcus pyogenes. They target a large fraction of T cell pools to set in motion a “cytokine storm” with severe and sometimes life-threatening consequences typically encountered in toxic shock syndrome (TSS). Given the rapidity with which TSS develops, designing timely and truly targeted therapies for this syndrome requires identification of key mediators of the cytokine storm’s initial wave. Equally important, early host responses to SAgs can be accompanied or followed by a state of immunosuppression, which in turn jeopardizes the host’s ability to combat and clear infections. Unlike in mouse models, the mechanisms underlying SAg-associated immunosuppression in humans are ill-defined. In this work, we have identified a population of innate-like T cells, called mucosa-associated invariant T (MAIT) cells, as the most powerful source of pro-inflammatory cytokines after exposure to SAgs. We have utilized primary human peripheral blood and hepatic mononuclear cells, mouse MAIT hybridoma lines, HLA-DR4-transgenic mice, MAIThighHLA-DR4+ bone marrow chimeras, and humanized NOD-scid IL-2Rγnull mice to demonstrate for the first time that: i) mouse and human MAIT cells are hyperresponsive to SAgs, typified by staphylococcal enterotoxin B (SEB); ii) the human MAIT cell response to SEB is rapid and far greater in magnitude than that launched by unfractionated conventional T, invariant natural killer T (iNKT) or γδ T cells, and is characterized by production of interferon (IFN)-γ, tumor necrosis factor (TNF)-α and interleukin (IL)-2, but not IL-17A; iii) high-affinity MHC class II interaction with SAgs, but not MHC-related protein 1 (MR1) participation, is required for MAIT cell activation; iv) MAIT cell responses to SEB can occur in a T cell receptor (TCR) Vβ–specific manner but are largely contributed by IL-12 and IL-18; v) as MAIT cells are primed by SAgs, they also begin to develop a molecular signature consistent with exhaustion and failure to participate in antimicrobial defense. Accordingly, they upregulate lymphocyte-activation gene 3 (LAG-3), T cell immunoglobulin and mucin-3 (TIM-3), and/or programmed cell death-1 (PD-1), and acquire an anergic phenotype that interferes with their cognate function against Klebsiella pneumoniae and Escherichia coli; vi) MAIT cell hyperactivation and anergy co-utilize a signaling pathway that is governed by p38 and MEK1/2. Collectively, our findings demonstrate a pathogenic, rather than protective, role for MAIT cells during infection. Furthermore, we propose a novel mechanism of SAg-associated immunosuppression in humans. MAIT cells may therefore provide an attractive therapeutic target for the management of both early and late phases of severe SAg-mediated illnesses. PMID:28632753

Simple programmable voltage reference for low frequency noise measurements

NASA Astrophysics Data System (ADS)

Ivanov, V. E.; Chye, En Un

2018-05-01

The paper presents a circuit design of a low-noise voltage reference based on an electric double-layer capacitor, a microcontroller and a general purpose DAC. A large capacitance value (1F and more) makes it possible to create low-pass filter with a large time constant, effectively reducing low-frequency noise beyond its bandwidth. Choosing the optimum value of the resistor in the RC filter, one can achieve the best ratio between the transient time, the deviation of the output voltage from the set point and the minimum noise cut-off frequency. As experiments have shown, the spectral density of the voltage at a frequency of 1 kHz does not exceed 1.2 nV/√Hz the maximum deviation of the output voltage from the predetermined does not exceed 1.4 % and depends on the holding time of the previous value. Subsequently, this error is reduced to a constant value and can be compensated.

Optimized MPPT algorithm for boost converters taking into account the environmental variables

NASA Astrophysics Data System (ADS)

Petit, Pierre; Sawicki, Jean-Paul; Saint-Eve, Frédéric; Maufay, Fabrice; Aillerie, Michel

2016-07-01

This paper presents a study on the specific behavior of the Boost DC-DC converters generally used for powering conversion of PV panels connected to a HVDC (High Voltage Direct Current) Bus. It follows some works pointing out that converter MPPT (Maximum Power Point Tracker) is severely perturbed by output voltage variations due to physical dependency of parameters as the input voltage, the output voltage and the duty cycle of the PWM switching control of the MPPT. As a direct consequence many converters connected together on a same load perturb each other because of the output voltage variations induced by fluctuations on the HVDC bus essentially due to a not insignificant bus impedance. In this paper we show that it is possible to include an internal computed variable in charge to compensate local and external variations to take into account the environment variables.

Measuring cross sections using a sag tape: a generalized procedure

Treesearch

Gary A. Ray; Walter F. Megahan

1979-01-01

A procedure was developed for surveying cross sections using a sag tape with unequal end elevations. The procedure is as accurate as traditional engineer's level surveys, is faster and easier, and can be programed for a digital computer by following the flow diagram which is provided.

Research on Centralized Voltage and Effective Inequality Identification Based on Circuit Analysis Method

NASA Astrophysics Data System (ADS)

Su, Yi; Wang, Feifeng; Lu, Yufeng; Huang, Huimin; Xia, Xiaofei

2017-09-01

This paper is based on affine function equation of the grid and OPF problem, discusses the equivalent of some inequality constraints variables optimizing. Further, we propose the model of injection current and set up the constraint sensitivity index of affine characteristics. The index can be used to identify the central point voltage and effective inequality of the system automatically. And then we can know how to compensate reactive power of the corresponding generator node and control the voltage to ensure the quality of the system voltage. When checking the effective inequalities we introduce cross-solving method of power flow. This provide a different idea for solving the power flow. The paper uses the results of the IEEE5 node examples to illustrate the validity and practicality of the proposed method.

Effects of voltage control in utility interactive dispersed storage and generation systems

NASA Technical Reports Server (NTRS)

Kirkham, H.; Das, R.

1983-01-01

When a small generator is connected to the distribution system, the voltage at the point of interconnection is determined largely by the system and not the generator. The effect on the generator, on the load voltage and on the distribution system of a number of different voltage control strategies in the generator is examined. Synchronous generators with three kinds of exciter control are considered, as well as induction generators and dc/ac inverters, with and without capacitor compensation. The effect of varying input power during operation (which may be experienced by generators based on renewable resources) is explored, as well as the effect of connecting and disconnecting the generator at ten percent of its rated power. Operation with a constant slightly lagging factor is shown to have some advantages.

Evaluating the relationship between lateral slip and repeated fold deformation along a transtensive step-over on the San Andreas fault at the Frazier Mountain site

NASA Astrophysics Data System (ADS)

Weldon, R. J.; Streig, A. R.; Frazier Mountain SoSAFE Trenching Team

2011-12-01

Transtensive step-overs known as sags are among the most ubiquitous features of strike slip faults. These structures create closed depressions that collect sediment, are often wet and thus preserve organic material that can be used to date the thick and rapidly accumulating section. It is clear from historical ruptures that these depressions grow incrementally with each earthquake. We are developing methods to carefully document and separate individual folding events, and to relate the amount of sagging or folding to the amount of horizontal slip creating the sag, with the goal of generating slip per event chronologies. This will be useful as sags are often the best sites for preserving evidence of earthquake timing, and determining slip at these sites will eliminate the ambiguity inherent in tying earthquake age data from micro-stratigraphic sites to nearby undated sites with good micro-geomorphic slip evidence. We apply this approach to the Frazier Mountain site on the Southern San Andreas fault where we integrate trenching, cone penetrometer testing (CPT), surveying, photomosaicing, B4 LiDAR data and GIS techniques to make a detailed 3D map of subsurface geology, fault traces and related folds across the site. These data are used to generate structure contour and isopach maps for key stratigraphic units in order to evaluate fold deformation of paleo-ground surfaces across a transtensional step-over on the San Andreas fault. Approximately 20 trenches show the main active trace of the San Andreas fault right stepping ~30 m over ~100 m along strike producing two small synclinal sags that dramatically thicken the stratigraphic section. The northwest sag is about 50 m long, 5 m wide, and the southwest sag measures 20 m long and about 8 m wide. The Frazier Mountain site has yielded good earthquake chronologies, and relationships between fold deformation and surface fault rupture for the last 6 earthquakes. We observe that the degree of sagging in the synclines varies along strike for each feature, but that the ratio of fold deformation between earthquake horizons remains constant in both synclines. The penultimate earthquake, E2, produced a depression that was infilled by gravel which was subsequently folded in the most recent earthquake in 1857. Fine-grained alluvial units overlie the gravel and fill the 1857 depression such that the current surface is relatively horizontal. E2 has double the observed folding associated with the 1857 event in the core of the NW syncline. Earthquake E6 has double the amount of fold deformation observed across the E3 paleo-surface in both sags, and three times the deformation observed on the E2 surface in the NW sag. Ratios of fold deformation between events are E2 = 2*E1, E6 = 3*E2, and E6 = 2*E3. We plan to model the folding to quantitatively assess the lateral offset, but to date we have only been able to establish minimum offset values (Scharer, Gibson, Weldon, Streig, this meeting). Qualitatively, the realitive amounts of folding suggest all slip events are similar to 1857, which had ~5 meters slip at this site.

Acanthite–argentite transformation in nanocrystalline silver sulfide and the Ag{sub 2}S/Ag nanoheterostructure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gusev, A. I., E-mail: gusev@ihim.uran.ru; Sadovnikov, S. I.

Nanocrystalline acanthite-structured silver sulfide of the monoclinic structure and a Ag{sub 2}S/Ag nanoheterostructure are produced. The high-temperature X-ray diffraction technique is applied to the in situ study of the (acanthite α-Ag{sub 2}S)–(argentite β-Ag{sub 2}S) phase transformation in nanocrystalline silver sulfide. The crystal structure of argentite is refined, and it is found that the content of vacant sites in the metal sublattice of argentite exceeds 92%. A model of a resistive switch, whose operation is based on the reversible acanthite–argentite transformation in a Ag{sub 2}S/Ag heterostructure, is considered.

Molecular mechanism of voltage sensing in voltage-gated proton channels

PubMed Central

Rebolledo, Santiago; Perez, Marta E.

2013-01-01

Voltage-gated proton (Hv) channels play an essential role in phagocytic cells by generating a hyperpolarizing proton current that electrically compensates for the depolarizing current generated by the NADPH oxidase during the respiratory burst, thereby ensuring a sustained production of reactive oxygen species by the NADPH oxidase in phagocytes to neutralize engulfed bacteria. Despite the importance of the voltage-dependent Hv current, it is at present unclear which residues in Hv channels are responsible for the voltage activation. Here we show that individual neutralizations of three charged residues in the fourth transmembrane domain, S4, all reduce the voltage dependence of activation. In addition, we show that the middle S4 charged residue moves from a position accessible from the cytosolic solution to a position accessible from the extracellular solution, suggesting that this residue moves across most of the membrane electric field during voltage activation of Hv channels. Our results show for the first time that the charge movement of these three S4 charges accounts for almost all of the measured gating charge in Hv channels. PMID:23401575

Nonhemolytic Streptococcus pyogenes Isolates That Lack Large Regions of the sag Operon Mediating Streptolysin S Production▿

PubMed Central

Yoshino, Miho; Murayama, Somay Y.; Sunaoshi, Katsuhiko; Wajima, Takeaki; Takahashi, Miki; Masaki, Junko; Kurokawa, Iku; Ubukata, Kimiko

2010-01-01

Among nonhemolytic Streptococcus pyogenes (group A streptococcus) strains (n = 9) isolated from patients with pharyngitis or acute otitis media, we identified three deletions in the region from the epf gene, encoding the extracellular matrix binding protein, to the sag operon, mediating streptolysin S production. PMID:20018818

Screening and identification of novel B cell epitopes of Toxoplasma gondii SAG1

PubMed Central

2013-01-01

Background The identification of protein epitopes is useful for diagnostic purposes and for the development of peptide vaccines. In this study, the epitopes of Toxoplasma gondii SAG1 were identified using synthetic peptide techniques with the aid of bioinformatics. Findings Eleven peptides derived from T. gondii SAG1 were assessed by ELISA using pig sera from different time points after infection. Four (PS4, PS6, PS10 and PS11), out of the eleven peptides tested were recognized by all sera. Then, shorter peptides that were derived from PS4, PS6, PS10 and PS11 were predicted using bioinformatics and tested by experimentation. Four out of nine shorter peptides were identified successfully (amino acids 106–120, 166–180, 289–300 and 313–332). Conclusions We have precisely located the epitopes of T. gondii SAG1 using pig sera collected at different time points after infection. The identified epitopes may be useful for the further study of epitope-based vaccines and diagnostic reagents. PMID:23631709

[Efficacy of stool antigen and serologic tests in the diagnosis of Helicobacter pylori in Ecuadorian population].

PubMed

Gómez, Néstor A; Alvarez, Ludwig R; Zapatier, Jorge A; Vargas, Paola E

2005-01-01

To assess the effectiveness in the Ecuadorian population of 2 non-invasive methods for the detection of the Helicobacter pylori: the stool antigens immunoassay (HpSAg) and the determination IgG serum of'antibodies. Eighty six dyspeptic patients were evaluated. In each, Helicobacter pylori presence was investigated with three methods: histology, HpSAg and serology. Sensibility and specificity values were obtained, as well as the positive and negative predictive values. The prevalence of Helicobacter pylori with the 3 tests was 89.53%. The sensibility, specificity, positive predictive value, and negative predictive value were: 42.5%, 69.2%, 88.6% and 17.6% with histology; 69.2%, 42.9%, 78.9% and 31% with HpSAg; 64.2%, 47.7%, 81.1% and 27.3% with serology. In the highly prevalent Ecuadorian setting, HpSAg and serology have relative low sensibility and specificity values. Based on our results, it is necessary to assess for conditions that could alter their results, and strategies to increase the sensibility of these tests, including the histology.

Glutenite bodies sequence division of the upper Es4 in northern Minfeng zone of Dongying Sag, Bohai Bay Basin, China

NASA Astrophysics Data System (ADS)

Shao, Xupeng

2017-04-01

Glutenite bodies are widely developed in northern Minfeng zone of Dongying Sag. Their litho-electric relationship is not clear. In addition, as the conventional sequence stratigraphic research method drawbacks of involving too many subjective human factors, it has limited deepening of the regional sequence stratigraphic research. The wavelet transform technique based on logging data and the time-frequency analysis technique based on seismic data have advantages of dividing sequence stratigraphy quantitatively comparing with the conventional methods. Under the basis of the conventional sequence research method, this paper used the above techniques to divide the fourth-order sequence of the upper Es4 in northern Minfeng zone of Dongying Sag. The research shows that the wavelet transform technique based on logging data and the time-frequency analysis technique based on seismic data are essentially consistent, both of which divide sequence stratigraphy quantitatively in the frequency domain; wavelet transform technique has high resolutions. It is suitable for areas with wells. The seismic time-frequency analysis technique has wide applicability, but a low resolution. Both of the techniques should be combined; the upper Es4 in northern Minfeng zone of Dongying Sag is a complete set of third-order sequence, which can be further subdivided into 5 fourth-order sequences that has the depositional characteristics of fine-upward sequence in granularity. Key words: Dongying sag, northern Minfeng zone, wavelet transform technique, time-frequency analysis technique ,the upper Es4, sequence stratigraphy

Human Leukocyte Antigen Class II Transgenic Mouse Model Unmasks the Significant Extrahepatic Pathology in Toxic Shock Syndrome

PubMed Central

Tilahun, Ashenafi Y.; Marietta, Eric V.; Wu, Tsung-Teh; Patel, Robin; David, Chella S.; Rajagopalan, Govindarajan

2011-01-01

Among the exotoxins produced by Staphylococcus aureus and Streptococcus pyogenes, the superantigens (SAgs) are the most potent T-cell activators known to date. SAgs are implicated in several serious diseases including toxic shock syndrome (TSS), Kawasaki disease, and sepsis. However, the immunopathogenesis of TSS and other diseases involving SAgs are still not completely understood. The commonly used conventional laboratory mouse strains do not respond robustly to SAgs in vivo. Therefore, they must be artificially rendered susceptible to TSS by using sensitizing agents such as d-galactosamine (d-galN), which skews the disease exclusively to the liver and, hence, is not representative of the disease in humans. SAg-induced TSS was characterized using transgenic mice expressing HLA class II molecules that are extremely susceptible to TSS without d-galN. HLA-DR3 transgenic mice recapitulated TSS in humans with extensive multiple-organ inflammation affecting the lung, liver, kidneys, heart, and small intestines. Heavy infiltration with T lymphocytes (both CD4+ and CD8+), neutrophils, and macrophages was noted. In particular, the pathologic changes in the small intestines were extensive and accompanied by significantly altered absorptive functions of the enterocytes. In contrast to massive liver failure alone in the d-galN sensitization model of TSS, findings of the present study suggest that gut dysfunction might be a key pathogenic event that leads to high morbidity and mortality in humans with TSS. PMID:21641398

Frontotemporal brain sagging syndrome

PubMed Central

Wicklund, M.R.; Mokri, B.; Drubach, D.A.; Boeve, B.F.; Parisi, J.E.

2011-01-01

Background: Behavioral variant frontotemporal dementia (bvFTD) is a relatively well-defined clinical syndrome. It is associated with frontal and temporal lobe structural/metabolic changes and pathologic findings of a neurodegenerative disease. We have been evaluating patients with clinical and imaging features partially consistent with bvFTD but with evidence also suggestive of brain sagging, which we refer to as frontotemporal brain sagging syndrome (FBSS). Methods: Retrospective medical chart review to identify all patients seen at our institution between 1996 and 2010, who had a clinical diagnosis of FTD and imaging evidence of brain sag. Results: Eight patients, 7 male and 1 female, were diagnosed with FBSS. The median age at symptom onset was 53 years. All patients had insidious onset and slow progression of behavioral and cognitive dysfunction accompanied by daytime somnolence and headache. Of the 5 patients with functional imaging, all showed evidence of hypometabolism of the frontotemporal regions. On brain MRI, all patients had evidence of brain sagging with distortion of the brainstem; 3 patients had diffuse pachymeningeal enhancement. CSF opening pressure was varied and CSF protein was mildly elevated. A definite site of CSF leak was not identified by myelogram or cisternography, except in one patient with a site highly suggestive of leak who subsequently underwent surgery confirming a CSF leak. In 2 patients with a neuropathologic examination, there was no evidence of a neurodegenerative disease. Conclusions: This case series demonstrates that FBSS may mimic typical bvFTD but should be recognized as an unusual presentation that is potentially treatable. PMID:21502595

Novel Twin Streptolysin S-Like Peptides Encoded in the sag Operon Homologue of Beta-Hemolytic Streptococcus anginosus

PubMed Central

Tabata, Atsushi; Nakano, Kota; Ohkura, Kazuto; Tomoyasu, Toshifumi; Kikuchi, Ken; Whiley, Robert A.

2013-01-01

Streptococcus anginosus is a member of the anginosus group streptococci, which form part of the normal human oral flora. In contrast to the pyogenic group streptococci, our knowledge of the virulence factors of the anginosus group streptococci, including S. anginosus, is not sufficient to allow a clear understanding of the basis of their pathogenicity. Generally, hemolysins are thought to be important virulence factors in streptococcal infections. In the present study, a sag operon homologue was shown to be responsible for beta-hemolysis in S. anginosus strains by random gene knockout. Interestingly, contrary to pyogenic group streptococci, beta-hemolytic S. anginosus was shown to have two tandem sagA homologues, encoding streptolysin S (SLS)-like peptides, in the sag operon homologue. Gene deletion and complementation experiments revealed that both genes were functional, and these SLS-like peptides were essential for beta-hemolysis in beta-hemolytic S. anginosus. Furthermore, the amino acid sequence of these SLS-like peptides differed from that of the typical SLS of S. pyogenes, especially in their propeptide domain, and an amino acid residue indicated to be important for the cytolytic activity of SLS in S. pyogenes was deleted in both S. anginosus homologues. These data suggest that SLS-like peptides encoded by two sagA homologues in beta-hemolytic S. anginosus may be potential virulence factors with a different structure essential for hemolytic activity and/or the maturation process compared to the typical SLS present in pyogenic group streptococci. PMID:23292771

TRIAC/SCR proportional control circuit

DOEpatents

Hughes, Wallace J.

1999-01-01

A power controller device which uses a voltage-to-frequency converter in conjunction with a zero crossing detector to linearly and proportionally control AC power being supplied to a load. The output of the voltage-to frequency converter controls the "reset" input of a R-S flip flop, while an "0" crossing detector controls the "set" input. The output of the flip flop triggers a monostable multivibrator controlling the SCR or TRIAC firing circuit connected to the load. Logic gates prevent the direct triggering of the multivibrator in the rare instance where the "reset" and "set" inputs of the flip flop are in coincidence. The control circuit can be supplemented with a control loop, providing compensation for line voltage variations.

A transcriptome-wide study on the microRNA- and the Argonaute 1-enriched small RNA-mediated regulatory networks involved in plant leaf senescence.

PubMed

Qin, J; Ma, X; Yi, Z; Tang, Z; Meng, Y

2016-03-01

Leaf senescence is an important physiological process during the plant life cycle. However, systemic studies on the impact of microRNAs (miRNAs) on the expression of senescence-associated genes (SAGs) are lacking. Besides, whether other Argonaute 1 (AGO1)-enriched small RNAs (sRNAs) play regulatory roles in leaf senescence remains unclear. In this study, a total of 5,123 and 1,399 AGO1-enriched sRNAs, excluding miRNAs, were identified in Arabidopsis thaliana and rice (Oryza sativa), respectively. After retrieving SAGs from the Leaf Senescence Database, all of the AGO1-enriched sRNAs and the miRBase-registered miRNAs of these two plants were included for target identification. Supported by degradome signatures, 200 regulatory pairs involving 120 AGO1-enriched sRNAs and 40 SAGs, and 266 regulatory pairs involving 64 miRNAs and 42 SAGs were discovered in Arabidopsis. Moreover, 13 genes predicted to interact with some of the above-identified target genes at protein level were validated as regulated by 17 AGO1-enriched sRNAs and ten miRNAs in Arabidopsis. In rice, only one SAG was targeted by three AGO1-enriched sRNAs, and one SAG was targeted by miR395. However, five AGO1-enriched sRNAs were conserved between Arabidopsis and rice. Target genes conserved between the two plants were identified for three of the above five sRNAs, pointing to the conserved roles of these regulatory pairs in leaf senescence or other developmental procedures. Novel targets were discovered for three of the five AGO1-enriched sRNAs in rice, indicating species-specific functions of these sRNA-target pairs. These results could advance our understanding of the sRNA-involved molecular processes modulating leaf senescence. © 2015 German Botanical Society and The Royal Botanical Society of the Netherlands.

Reverse enzyme-linked immunosorbent assay using monoclonal antibodies against SAG1-related sequence, SAG2A, and p97 antigens from Toxoplasma gondii to detect specific immunoglobulin G (IgG), IgM, and IgA antibodies in human sera.

PubMed

Carvalho, Fernando R; Silva, Deise A O; Cunha-Júnior, Jair P; Souza, Maria A; Oliveira, Taísa C; Béla, Samantha R; Faria, Gabriele G; Lopes, Carolina S; Mineo, José R

2008-08-01

The present study aimed to evaluate the performance of three monoclonal antibodies (MAbs) in reverse enzyme-linked immunosorbent assays (ELISAs) for detecting immunoglobulin G (IgG), IgM, and IgA antibodies against Toxoplasma gondii in 175 serum samples from patients at different stages of T. gondii infection, as defined by both serological and clinical criteria, as follows: recent (n = 45), transient (n = 40), and chronic (n = 55) infection as well as seronegative subjects (n = 35). The results were compared with those obtained by indirect ELISA using soluble Toxoplasma total antigen (STAg). Our data demonstrated that MAb A3A4 recognizes a conformational epitope in SAG1-related-sequence (SRS) antigens, while A4D12 and 1B8 recognize linear epitopes defined as SAG2A surface antigen and p97 cytoplasmatic antigen, respectively. Reverse ELISA for IgG with A3A4 or A4D12 MAbs was highly correlated with indirect ELISA for anti-STAg IgG, whereas only A4D12 reverse ELISA showed high correlation with indirect ELISA for IgM and IgA isotypes. To our knowledge, this is the first report analyzing the performance of a reverse ELISA for simultaneous detection of IgG, IgM, and IgA isotypes active toward native SAG2A, SRS, and p97 molecules from STAg, using a panel of human sera from patients with recent and chronic toxoplasmosis. Thus, reverse ELISA based on the capture of native SAG2A and SRS antigens of STAg by MAbs could be an additional approach for strengthening the helpfulness of serological tests assessing the stage of infection, particularly in combination with highly sensitive and specific assays that are frequently used nowadays for diagnosis of toxoplasmosis during pregnancy or congenital infection in newborns.

Rapid and Rigorous IL-17A Production by a Distinct Subpopulation of Effector Memory T Lymphocytes Constitutes a Novel Mechanism of Toxic Shock Syndrome Immunopathology.

PubMed

Szabo, Peter A; Goswami, Ankur; Mazzuca, Delfina M; Kim, Kyoungok; O'Gorman, David B; Hess, David A; Welch, Ian D; Young, Howard A; Singh, Bhagirath; McCormick, John K; Haeryfar, S M Mansour

2017-04-01

Toxic shock syndrome (TSS) is caused by staphylococcal and streptococcal superantigens (SAgs) that provoke a swift hyperinflammatory response typified by a cytokine storm. The precipitous decline in the host's clinical status and the lack of targeted therapies for TSS emphasize the need to identify key players of the storm's initial wave. Using a humanized mouse model of TSS and human cells, we herein demonstrate that SAgs elicit in vitro and in vivo IL-17A responses within hours. SAg-triggered human IL-17A production was characterized by remarkably high mRNA stability for this cytokine. A distinct subpopulation of CD4 + effector memory T (T EM ) cells that secrete IL-17A, but not IFN-γ, was responsible for early IL-17A production. We found mouse "T EM -17" cells to be enriched within the intestinal epithelium and among lamina propria lymphocytes. Furthermore, interfering with IL-17A receptor signaling in human PBMCs attenuated the expression of numerous inflammatory mediators implicated in the TSS-associated cytokine storm. IL-17A receptor blockade also abrogated the secondary effect of SAg-stimulated PBMCs on human dermal fibroblasts as judged by C/EBP δ expression. Finally, the early IL-17A response to SAgs was pathogenic because in vivo neutralization of IL-17A in humanized mice ameliorated hepatic and intestinal damage and reduced mortality. Together, our findings identify CD4 + T EM cells as a key effector of TSS and reveal a novel role for IL-17A in TSS immunopathogenesis. Our work thus elucidates a pathogenic, as opposed to protective, role for IL-17A during Gram-positive bacterial infections. Accordingly, the IL-17-IL-17R axis may provide an attractive target for the management of SAg-mediated illnesses. Copyright © 2017 by The American Association of Immunologists, Inc.

Pattern Recognition Application of Support Vector Machine for Fault Classification of Thyristor Controlled Series Compensated Transmission Lines

NASA Astrophysics Data System (ADS)

Yashvantrai Vyas, Bhargav; Maheshwari, Rudra Prakash; Das, Biswarup

2016-06-01

Application of series compensation in extra high voltage (EHV) transmission line makes the protection job difficult for engineers, due to alteration in system parameters and measurements. The problem amplifies with inclusion of electronically controlled compensation like thyristor controlled series compensation (TCSC) as it produce harmonics and rapid change in system parameters during fault associated with TCSC control. This paper presents a pattern recognition based fault type identification approach with support vector machine. The scheme uses only half cycle post fault data of three phase currents to accomplish the task. The change in current signal features during fault has been considered as discriminatory measure. The developed scheme in this paper is tested over a large set of fault data with variation in system and fault parameters. These fault cases have been generated with PSCAD/EMTDC on a 400 kV, 300 km transmission line model. The developed algorithm has proved better for implementation on TCSC compensated line with its improved accuracy and speed.

Serodiagnosis of Toxoplasma gondii infection in farm animals (horses, swine, and sheep) by enzyme-linked immunosorbent assay using chimeric antigens.

PubMed

Ferra, Bartłomiej; Holec-Gąsior, Lucyna; Kur, Józef

2015-10-01

Toxoplasma gondii infects all warm-blooded animals including humans, causing serious public health problems and great economic loss in the animal husbandry. Commonly used serological tests for diagnosis of toxoplasmosis involve preparation of whole Toxoplasma lysate antigen (TLA) from tachyzoites. The production of this antigen is associated with high costs and lengthy preparation and the possibility of staff infection. There are also some difficulties in the standardization of such tests. One approach in order to improve the diagnosis of T. gondii infection is to use recombinant chimeric antigens in place of the TLA, which was confirmed by studies in the serodiagnosis of toxoplasmosis in humans. In this paper, we assess, for the first time, the diagnostic utility of five T. gondii recombinant chimeric antigens (MIC1-MAG1-SAG1S, SAG1L-MIC1-MAG1, SAG2-GRA1-ROP1S, SAG2-GRA1-ROP1L, and GRA1-GRA2-GRA6) in immunoglobulin G (IgG) enzyme-linked immunosorbent assays (IgG ELISAs) with sera from three different groups of livestock animals (horses, pigs, and sheep). The reactivity of individual chimeric antigens was analyzed in relation to the results obtained in IgG ELISAs based on a mixture of three antigens (M1: rSAG1+rMIC1+rMAG1, M2: rSAG2+rGRA1+rROP1, and M3: rGRA1+rGRA2+rGRA6) and referenced to TLA. All chimeric antigens were characterized by high specificity (100%), and the sensitivity of the IgG ELISAs based on chimeric antigens was variable (between 28.4% and 100%) and mainly dependent on the animal species. The chimeric antigens were generally more reactive than mixtures of three antigens. The most effective for the diagnosis of toxoplasmosis was SAG2-GRA1-ROP1L, which can detect specific anti-T. gondii antibodies in 100%, 93.8%, and 100% of positive serum samples from horses, pigs, and sheep, respectively. The present study shows that recombinant chimeric antigens can be successfully used to diagnose T. gondii infection in farm animals, and can replace the commonly used TLA. Copyright © 2015. Published by Elsevier Ireland Ltd.

The virtual infinite capacitor

NASA Astrophysics Data System (ADS)

Yona, Guy; Weiss, George

2017-01-01

We define the virtual infinite capacitor (VIC) as a nonlinear capacitor that has the property that for an interval of the charge Q (the operating range), the voltage V remains constant. We propose a lossless approximate realisation for the VIC as a simple circuit with two controllers: a voltage controller acts fast to maintain the desired terminal voltage, while a charge controller acts more slowly and maintains the charge Q in the desired operating range by influencing the incoming current. The VIC is useful as a filter capacitor for various applications, for example, power factor compensators (PFC), as we describe. In spite of using small capacitors, the VIC can replace a very large capacitor in applications that do not require substantial energy storage. We give simulation results for a PFC working in critical conduction mode with a VIC for output voltage filtering.

Quasi-multi-pulse voltage source converter design with two control degrees of freedom

NASA Astrophysics Data System (ADS)

Vural, A. M.; Bayindir, K. C.

2015-05-01

In this article, the design details of a quasi-multi-pulse voltage source converter (VSC) switched at line frequency of 50 Hz are given in a step-by-step process. The proposed converter is comprised of four 12-pulse converter units, which is suitable for the simulation of single-/multi-converter flexible alternating current transmission system devices as well as high voltage direct current systems operating at the transmission level. The magnetic interface of the converter is originally designed with given all parameters for 100 MVA operation. The so-called two-angle control method is adopted to control the voltage magnitude and the phase angle of the converter independently. PSCAD simulation results verify both four-quadrant converter operation and closed-loop control of the converter operated as static synchronous compensator (STATCOM).

Fuzzy Current-Mode Control and Stability Analysis

NASA Technical Reports Server (NTRS)

Kopasakis, George

2000-01-01

In this paper a current-mode control (CMC) methodology is developed for a buck converter by using a fuzzy logic controller. Conventional CMC methodologies are based on lead-lag compensation with voltage and inductor current feedback. In this paper the converter lead-lag compensation will be substituted with a fuzzy controller. A small-signal model of the fuzzy controller will also be developed in order to examine the stability properties of this buck converter control system. The paper develops an analytical approach, introducing fuzzy control into the area of CMC.

Detection of antibodies against Sarcocystis neurona, neospora spp., and Toxoplasma gondii in horses from Costa Rica

USDA-ARS?s Scientific Manuscript database

Serum samples from 315 horses from Costa Rica, Central America were examined for the presence of antibodies against Sarcocystis neurona, Neospora spp., and Toxoplasma gondii using the SnSAG2 ELISA, the NhSAG1 ELISA, and the modified agglutination test, respectively. Anti-S. neurona antibodies were f...

76 FR 47009 - Marine Mammals; Incidental Take During Specified Activities

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-03

..., some of these fields include associated satellite oilfields: Sag Delta North, Eider, North Prudhoe Bay... exploration) and CD- 4 (CD South) are in the Colville Delta. The CD-3 drill site is located north of CD-1... oil from the Ivishak formation: Eider produces about 110 barrels per day, and Sag Delta North produces...

The Effects of Multi-Age Grouping on Young Children and Teacher Preparation.

ERIC Educational Resources Information Center

Jensen, Melanie K.; Green, Virginia P.

1993-01-01

This literature review on the effects of multiage groupings (MAGs) in the primary grades supports their use and argues that children in MAGs perform as well academically as children in single-age groupings (SAGs) and develop better self-concept and school attitudes than children in SAGs. Expresses concerns over lack of training and support for…

Wireless Low-Power Integrated Basal-Body-Temperature Detection Systems Using Teeth Antennas in the MedRadio Band.

PubMed

Yang, Chin-Lung; Zheng, Gou-Tsun

2015-11-20

This study proposes using wireless low power thermal sensors for basal-body-temperature detection using frequency modulated telemetry devices. A long-term monitoring sensor requires low-power circuits including a sampling circuit and oscillator. Moreover, temperature compensated technologies are necessary because the modulated frequency might have additional frequency deviations caused by the varying temperature. The temperature compensated oscillator is composed of a ring oscillator and a controlled-steering current source with temperature compensation, so the output frequency of the oscillator does not drift with temperature variations. The chip is fabricated in a standard Taiwan Semiconductor Manufacturing Company (TSMC) 0.18-μm complementary metal oxide semiconductor (CMOS) process, and the chip area is 0.9 mm². The power consumption of the sampling amplifier is 128 µW. The power consumption of the voltage controlled oscillator (VCO) core is less than 40 µW, and the output is -3.04 dBm with a buffer stage. The output voltage of the bandgap reference circuit is 1 V. For temperature measurements, the maximum error is 0.18 °C with a standard deviation of ±0.061 °C, which is superior to the required specification of 0.1 °C.

Contact Force Compensated Thermal Stimulators for Holistic Haptic Interfaces.

PubMed

Sim, Jai Kyoung; Cho, Young-Ho

2016-05-01

We present a contact force compensated thermal stimulator that can provide a consistent tempera- ture sensation on the human skin independent of the contact force between the thermal stimulator and the skin. Previous passive thermal stimulators were not capable of providing a consistent tem- perature on the human skin even when using identical heat source voltage due to an inconsistency of the heat conduction, which changes due to the force-dependent thermal contact resistance. We propose a force-based feedback method that monitors the contact force and controls the heat source voltage according to this contact force, thus providing consistent temperature on the skin. We composed a heat circuit model equivalent to the skin heat-transfer rate as it is changed by the contact forces; we obtained the optimal voltage condition for the constant skin heat-transfer rate independent of the contact force using a numerical estimation simulation tool. Then, in the experiment, we heated real human skin at the obtained heat source voltage condition, and investigated the skin heat transfer-rate by measuring the skin temperature at various times at different levels of contact force. In the numerical estimation results, the skin heat-transfer rate for the contact forces showed a linear profile in the contact force range of 1-3 N; from this profile we obtained the voltage equation for heat source control. In the experimental study, we adjusted the heat source voltage according to the contact force based on the obtained equation. As a result, without the heat source voltage control for the contact forces, the coefficients of variation (CV) of the skin heat-transfer rate in the contact force range of 1-3 N was found to be 11.9%. On the other hand, with the heat source voltage control for the contact forces, the CV of the skin heat-transfer rate in the contact force range of 1-3 N was found to be barely 2.0%, which indicate an 83.2% improvement in consistency compared to the skin heat-transfer rate without the heat source voltage control. The present technique provides a consistent temperature sensation on the human skin independent of the body movement environment; therefore, it has high potential for use in holistic haptic interfaces that have thermal displays.

Experimental investigation of distinguishable and non-distinguishable grayscales applicable in active-matrix organic light-emitting diodes for quality engineering

NASA Astrophysics Data System (ADS)

Yang, Henglong; Chang, Wen-Cheng; Lin, Yu-Hsuan; Chen, Ming-Hong

2017-08-01

The distinguishable and non-distinguishable 6-bit (64) grayscales of green and red organic light-emitting diode (OLED) were experimentally investigated by using high-sensitive photometric instrument. The feasibility of combining external detection system for quality engineering to compensate the grayscale loss based on preset grayscale tables was also investigated by SPICE simulation. The degradation loss of OLED deeply affects image quality as grayscales become inaccurate. The distinguishable grayscales are indicated as those brightness differences and corresponding current increments are differentiable by instrument. The grayscales of OLED in 8-bit (256) or higher may become nondistinguishable as current or voltage increments are in the same order of noise level in circuitry. The distinguishable grayscale tables for individual red, green, blue, and white colors can be experimentally established as preset reference for quality engineering (QE) in which the degradation loss is compensated by corresponding grayscale numbers shown in preset table. The degradation loss of each OLED colors is quantifiable by comparing voltage increments to those in preset grayscale table if precise voltage increments are detectable during operation. The QE of AMOLED can be accomplished by applying updated grayscale tables. Our preliminary simulation result revealed that it is feasible to quantify degradation loss in terms of grayscale numbers by using external detector circuitry.

40 CFR 92.106 - Equipment for loading the engine.

Code of Federal Regulations, 2011 CFR

2011-07-01

... loading the locomotive engine-alternator/generator assembly electrically, and for measurement of the... angle compensation; meter(s) for measurement of the current through the load bank (a calibrated electrical shunt and voltmeter is allowed for current measurement); meter(s) to measure the voltage across...

40 CFR 92.106 - Equipment for loading the engine.

Code of Federal Regulations, 2012 CFR

2012-07-01

... loading the locomotive engine-alternator/generator assembly electrically, and for measurement of the... angle compensation; meter(s) for measurement of the current through the load bank (a calibrated electrical shunt and voltmeter is allowed for current measurement); meter(s) to measure the voltage across...

40 CFR 92.106 - Equipment for loading the engine.

Code of Federal Regulations, 2014 CFR

2014-07-01

... loading the locomotive engine-alternator/generator assembly electrically, and for measurement of the... angle compensation; meter(s) for measurement of the current through the load bank (a calibrated electrical shunt and voltmeter is allowed for current measurement); meter(s) to measure the voltage across...

40 CFR 92.106 - Equipment for loading the engine.

Code of Federal Regulations, 2013 CFR

2013-07-01

... loading the locomotive engine-alternator/generator assembly electrically, and for measurement of the... angle compensation; meter(s) for measurement of the current through the load bank (a calibrated electrical shunt and voltmeter is allowed for current measurement); meter(s) to measure the voltage across...

Note: Rapid offset reduction of impedance bridges taking into account instrumental damping and phase shifting.

PubMed

van der Wel, C M; Kortschot, R J; Bakelaar, I A; Erné, B H; Kuipers, B W M

2013-03-01

The sensitivity of an imperfectly balanced impedance bridge is limited by the remaining offset voltage. Here, we present a procedure for offset reduction in impedance measurements using a lock-in amplifier, by applying a complex compensating voltage external to the bridge. This procedure takes into account instrumental damping and phase shifting, which generally occur at the high end of the operational frequency range. Measurements demonstrate that the output of the circuit rapidly converges to the instrumentally limited noise at any frequency.

Studies of dished accelerator grids for 30-cm ion thrusters

NASA Technical Reports Server (NTRS)

Rawlin, V. K.

1973-01-01

Eighteen geometrically different sets of dished accelerator grids were tested on five 30-cm thrusters. The geometric variation of the grids included the grid-to-grid spacing, the screen and accelerator hole diameters and thicknesses, the screen and accelerator open area fractions, ratio of dish depth to dish diameter, compensation, and aperture shape. In general, the data taken over a range of beam currents for each grid set included the minimum total accelerating voltage required to extract a given beam current and the minimum accelerator grid voltage required to prevent electron backstreaming.

Compensated pulsed alternator

DOEpatents

Weldon, William F.; Driga, Mircea D.; Woodson, Herbert H.

1980-01-01

This invention relates to an electromechanical energy converter with inertial energy storage. The device, a single phase, two or multi-pole alternator with stationary field coils, and a rotating armature is provided. The rotor itself may be of laminated steel for slower pulses or for faster pulses should be nonmagnetic and electrically nonconductive in order to allow rapid penetration of the field as the armature coil rotates. The armature coil comprises a plurality of power generating conductors mounted on the rotor. The alternator may also include a stationary or counterrotating compensating coil to increase the output voltage thereof and to reduce the internal impedance of the alternator at the moment of peak outout. As the machine voltage rises sinusoidally, an external trigger switch is adapted to be closed at the appropriate time to create the desired output current from said alternator to an external load circuit, and as the output current passes through zero a self-commutating effect is provided to allow the switch to disconnect the generator from the external circuit.

Possibility of transforming the electronic structure of one species of graphene adatoms into that of another by application of gate voltage: First-principles calculations

NASA Astrophysics Data System (ADS)

Chan, Kevin T.; Lee, Hoonkyung; Cohen, Marvin L.

2011-10-01

Graphene provides many advantages for controlling the electronic structure of adatoms and other adsorbates via gating. Using the projected density of states and charge density obtained from first-principles density-functional periodic supercell calculations, we investigate the possibility of performing “alchemy” of adatoms on graphene, i.e., transforming the electronic structure of one species of adatom into that of another species by application of a gate voltage. Gating is modeled as a change in the number of electrons in the unit cell, with the inclusion of a compensating uniform background charge. Within this model and the generalized gradient approximation to the exchange-correlation functional, we find that such transformations are possible for K, Ca, and several transition-metal adatoms. Gate control of the occupation of the p states of In on graphene is also investigated. The validity of the supercell approximation with uniform compensating charge and the model for exchange and correlation is also discussed.

PI and fuzzy logic controllers for shunt Active Power Filter--a report.

PubMed

P, Karuppanan; Mahapatra, Kamala Kanta

2012-01-01

This paper presents a shunt Active Power Filter (APF) for power quality improvements in terms of harmonics and reactive power compensation in the distribution network. The compensation process is based only on source current extraction that reduces the number of sensors as well as its complexity. A Proportional Integral (PI) or Fuzzy Logic Controller (FLC) is used to extract the required reference current from the distorted line-current, and this controls the DC-side capacitor voltage of the inverter. The shunt APF is implemented with PWM-current controlled Voltage Source Inverter (VSI) and the switching patterns are generated through a novel Adaptive-Fuzzy Hysteresis Current Controller (A-F-HCC). The proposed adaptive-fuzzy-HCC is compared with fixed-HCC and adaptive-HCC techniques and the superior features of this novel approach are established. The FLC based shunt APF system is validated through extensive simulation for diode-rectifier/R-L loads. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.

Wide Bandgap Extrinsic Photoconductive Switches

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sullivan, James S.

2013-07-03

Semi-insulating Gallium Nitride, 4H and 6H Silicon Carbide are attractive materials for compact, high voltage, extrinsic, photoconductive switches due to their wide bandgap, high dark resistance, high critical electric field strength and high electron saturation velocity. These wide bandgap semiconductors are made semi-insulating by the addition of vanadium (4H and 6HSiC) and iron (2H-GaN) impurities that form deep acceptors. These deep acceptors trap electrons donated from shallow donor impurities. The electrons can be optically excited from these deep acceptor levels into the conduction band to transition the wide bandgap semiconductor materials from a semi-insulating to a conducting state. Extrinsic photoconductivemore » switches with opposing electrodes have been constructed using vanadium compensated 6H-SiC and iron compensated 2H-GaN. These extrinsic photoconductive switches were tested at high voltage and high power to determine if they could be successfully used as the closing switch in compact medical accelerators.« less

Fine Output Voltage Control Method considering Time-Delay of Digital Inverter System for X-ray Computed Tomography

NASA Astrophysics Data System (ADS)

Shibata, Junji; Kaneko, Kazuhide; Ohishi, Kiyoshi; Ando, Itaru; Ogawa, Mina; Takano, Hiroshi

This paper proposes a new output voltage control for an inverter system, which has time-delay and nonlinear load. In the next generation X-ray computed tomography of a medical device (X-ray CT) that uses the contactless power transfer method, the feedback signal often contains time-delay due to AD/DA conversion and error detection/correction time. When the PID controller of the inverter system is received the adverse effects of the time-delay, the controller often has an overshoot and a oscillated response. In order to overcome this problem, this paper proposes a compensation method based on the Smith predictor for an inverter system having a time-delay and the nonlinear loads which are the diode bridge rectifier and X-ray tube. The proposed compensation method consists of the hybrid Smith predictor system based on an equivalent analog circuit and DSP. The experimental results confirm the validity of the proposed system.

Improved control strategy for PI-R current of DFIG considering voltage and current harmonics compensation

NASA Astrophysics Data System (ADS)

Song, S. Y.; Liu, Q. H.; Zhao, Y. N.; Liu, S. Y.

2016-08-01

With the rapid development of wind power generation, the related research of wind power control and integration issues has attracted much attention, and the focus of the research are shifting away from the ideal power grid environment to the actual power grid environment. As the main stream wind turbine generator, a doubly-fed induction generator (DFIG) is connected to the power grid directly by its stator, so it is particularly sensitive to the power grid. This paper studies the improvement of DFIG control technology in the power grid harmonic environment. Based on the DFIG dynamic model considering the power grid harmonic environment, this paper introduces the shortcomings of the common control strategy of DFIG, and puts forward the enhanced method. The decoupling control of the system is realized by compensating the coupling between the rotor harmonic voltage and harmonic current, improving the control performance. In addition, the simulation experiments on PSCAD/EMTDC are carried out to verify the correctness and effectiveness of the improved scheme.

A CMOS micromachined capacitive tactile sensor with integrated readout circuits and compensation of process variations.

PubMed

Tsai, Tsung-Heng; Tsai, Hao-Cheng; Wu, Tien-Keng

2014-10-01

This paper presents a capacitive tactile sensor fabricated in a standard CMOS process. Both of the sensor and readout circuits are integrated on a single chip by a TSMC 0.35 μm CMOS MEMS technology. In order to improve the sensitivity, a T-shaped protrusion is proposed and implemented. This sensor comprises the metal layer and the dielectric layer without extra thin film deposition, and can be completed with few post-processing steps. By a nano-indenter, the measured spring constant of the T-shaped structure is 2.19 kNewton/m. Fully differential correlated double sampling capacitor-to-voltage converter (CDS-CVC) and reference capacitor correction are utilized to compensate process variations and improve the accuracy of the readout circuits. The measured displacement-to-voltage transductance is 7.15 mV/nm, and the sensitivity is 3.26 mV/μNewton. The overall power dissipation is 132.8 μW.

Control of Established Colon Cancer Xenografts Using a Novel Humanized Single Chain Antibody-Streptococcal Superantigen Fusion Protein Targeting the 5T4 Oncofetal Antigen

PubMed Central

Patterson, Kelcey G.; Dixon Pittaro, Jennifer L.; Bastedo, Peter S.; Hess, David A.; Haeryfar, S. M. Mansour; McCormick, John K.

2014-01-01

Superantigens (SAgs) are microbial toxins that cross-link T cell receptors with major histocompatibility class II (MHC-II) molecules leading to the activation of large numbers of T cells. Herein, we describe the development and preclinical testing of a novel tumor-targeted SAg (TTS) therapeutic built using the streptococcal pyrogenic exotoxin C (SpeC) SAg and targeting cancer cells expressing the 5T4 tumor-associated antigen (TAA). To inhibit potentially harmful widespread immune cell activation, a SpeC mutation within the high-affinity MHC-II binding interface was generated (SpeCD203A) that demonstrated a pronounced reduction in mitogenic activity, yet this mutant could still induce immune cell-mediated cancer cell death in vitro. To target 5T4+ cancer cells, we engineered a humanized single chain variable fragment (scFv) antibody to recognize 5T4 (scFv5T4). Specific targeting of scFv5T4 was verified. SpeCD203A fused to scFv5T4 maintained the ability to activate and induce immune cell-mediated cytotoxicity of colorectal cancer cells. Using a xenograft model of established human colon cancer, we demonstrated that the SpeC-based TTS was able to control the growth and spread of large tumors in vivo. This required both TAA targeting by scFv5T4 and functional SAg activity. These studies lay the foundation for the development of streptococcal SAgs as ‘next-generation’ TTSs for cancer immunotherapy. PMID:24736661

Local administration of a hedgehog agonist accelerates fracture healing in a mouse model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kashiwagi, Miki; Division of Clinical Biotechnology, The University of Tokyo Graduate School of Medicine, Bunkyo-ku, Tokyo, 113-0033; Hojo, Hironori

Bone fracture healing is processed through multiple biological stages including the transition from cartilaginous callus to bony callus formation. Because of its specific, temporal and indispensable functions demonstrated by mouse genetic studies, Hedgehog (Hh) signaling is one of the most potent signaling pathways involved in these processes, but the effect of Hh-signaling activation by small compounds on the repair process had not yet been addressed. Here we examined therapeutic effects of local and one shot-administration of the Hh agonist known as smoothened agonist (SAG) on bone fracture healing in a mouse model. A quantitative analysis with three-dimensional micro-computed tomography showedmore » that SAG administration increased the size of both the cartilaginous callus and bony callus at 14 days after the surgery. A histological analysis showed that SAG administration increased the number of cells expressing a proliferation marker and a chondrocyte marker in cartilaginous callus as well as the cells expressing an osteoblast marker in bony callus. These results indicate that the SAG administration resulted in an enhancement of callus formation during bone fracture healing, which is at least in part mediated by an increase in chondrocyte proliferation in cartilaginous callus and the promotion of bone formation in bony callus. Therapeutic strategies with a SAG-mediated protocol may thus be useful for the treatment of bone fractures. - Highlights: • Local administration of a Hh agonist accelerates callus formation. • The Hh agonist administration promotes chondrocyte proliferation in the soft callus. • The Hh agonist administration increases osteoblast formation in the hard callus.« less

Prevalence and genetic characterization of Toxoplasma gondii in free-range chickens from grocery stores and farms in Maryland, Ohio and Massachusetts, USA.

PubMed

Ying, Yuqing; Verma, Shiv K; Kwok, Oliver C H; Alibana, Fatima; Mcleod, Rima; Su, Chunlei; Dubey, Jitender P; Pradhan, Abani K

2017-05-01

Chickens are considered important in the epidemiology of Toxoplasma gondii. Chicken hearts (n = 1185) obtained from grocery stores were tested for T. gondii infection. Antibodies to T. gondii were assayed in fluid removed from the heart cavity using the modified agglutination test (MAT) at 1:5, 1:25, and 1:100 dilutions. MAT antibodies were detected in 222 hearts at 1:5 dilution and 8 hearts at 1:25 dilution, but none were positive at 1:100 dilution. Seropositive (n = 230, 19.4%) chicken hearts were bioassayed in mice and seronegative (n = 157) chickens were bioassayed in cats. Viable T. gondii was not isolated from any hearts by bioassays in mice. The 2 cats fed 60 and 97 hearts did not excrete T. gondii oocysts. The results indicate a low prevalence of viable T. gondii in chickens from grocery stores. Molecular typing of 23 archived T. gondii strains isolated from free-range chickens from Ohio and Massachusetts using the 10 PCR-RFLP markers including SAG1, SAG2 (5'-3'SAG2 and altSAG2), SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico revealed that seven were ToxoDB PCR-RFLP genotype #1, 11 were genotype #2, one was genotype #3, three were genotype #170, and one was mixed genotype. These results indicate that the clonal genotypes #1 (type II), #2 (type III), and #3 (type II variant) are common in free-range chickens.

Genetic characterization of Toxoplasma gondii from pigs from different localities in China by PCR-RFLP.

PubMed

Jiang, Hai-Hai; Huang, Si-Yang; Zhou, Dong-Hui; Zhang, Xiao-Xuan; Su, Chunlei; Deng, Shun-Zhou; Zhu, Xing-Quan

2013-08-07

Toxoplasma gondii is a widely prevalent protozoan parasite that causes serious toxoplasmosis in humans and animals. The present study aimed to determine the genetic diversity of T. gondii isolates from pigs in Jiangxi, Sichuan, Guangdong Provinces and Chongqing Municipality in China using multilocous polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technology. A total of 38 DNA samples were extracted from hilar lymph nodes of pigs with suspected toxoplasmosis, and were detected for the presence of T. gondii by semi-nested PCR of B1 gene. The positive DNA samples were typed at 11 genetic markers, including 10 nuclear loci, namely, SAG1, 5'-SAG2 and 3'-SAG2, alternative SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and an apicoplast locus Apico. Twenty-five of the 38 DNA samples were T. gondii B1 gene positive. Complete genotyping data for all loci could be obtained for 17 of the 25 samples. Two genotypes were revealed (ToxoDB PCR-RFLP genotypes #9 and #3). Sixteen samples belong to genotype #9 which is the major lineage in mainland China and one sample belongs to genotype #3 which is Type II variant. To our knowledge, this is the first report of genetic typing of T. gondii isolates from pigs in Jiangxi, Sichuan Province and Chongqing Municipality, and the first report of ToxoDB #3 T. gondii from pigs in China. These results have implications for the prevention and control of foodborne toxoplasmosis in humans.

Immune responses to retinal autoantigens and peptides in equine recurrent uveitis.

PubMed

Deeg, C A; Kaspers, B; Gerhards, H; Thurau, S R; Wollanke, B; Wildner, G

2001-02-01

To test the hypothesis that autoimmune mechanisms are involved in horses in which equine recurrent uveitis (ERU) develops spontaneously. Material obtained from horses treated for spontaneous disease by therapeutic routine vitrectomy was analyzed for total IgG content and IgG specific for S-Antigen (S-Ag) and interphotoreceptor retinoid-binding protein (IRBP). The cellular infiltrate of the vitreous was analyzed by differential counts of cytospin preparations and flow cytometry using equine lymphocyte-specific antibodies. Antigen-specific proliferation assays were performed comparing peripheral blood lymphocytes (PBLs) with vitreal lymphocytes by stimulation with S-Ag and several S-Ag- and IRBP-derived peptides. The total IgG content of specimens from horses with ERU was very high with great variability among the investigated samples (11.5 +/- 8.0 mg). Autoantibodies to S-Ag or IRBP or both were found in 72% of vitreous specimens from horses with uveitis. The leukocyte infiltrates (up to 2 x 10(8) cells per sample) were dominated by lymphocytes (>90%) in most cases (22/32). Flow cytometry showed that more than 50% of these cells were CD4(+) T cells. In vitro stimulation of vitreal lymphocytes, but not of PBL, showed a strong proliferative response to peptides derived from S-Ag or IRBP in 9 of 12 patients. In the eyes of horses with ERU, IgG antibodies and autoreactive T cells specific for retinal antigens were detected. These results strongly support the hypothesis that ERU is an autoimmune-mediated disease and is highly similar to recurrent uveitis in humans in both clinical and immunologic parameters.

Precision Voltage Referencing Techniques in MOS Technology.

NASA Astrophysics Data System (ADS)

Song, Bang-Sup

With the increasing complexity of functions on a single MOS chip, precision analog cicuits implemented in the same technology are in great demand so as to be integrated together with digital circuits. The future development of MOS data acquisition systems will require precision on-chip MOS voltage references. This dissertation will probe two most promising configurations of on-chip voltage references both in NMOS and CMOS technologies. In NMOS, an ion-implantation effect on the temperature behavior of MOS devices is investigated to identify the fundamental limiting factors of a threshold voltage difference as an NMOS voltage source. For this kind of voltage reference, the temperature stability on the order of 20ppm/(DEGREES)C is achievable with a shallow single-threshold implant and a low-current, high-body bias operation. In CMOS, a monolithic prototype bandgap reference is designed, fabricated and tested which embodies a curvature compensation and exhibits a minimized sensitivity to the process parameter variation. Experimental results imply that an average temperature stability on the order of 10ppm/(DEGREES)C with a production spread of less than 10ppm/(DEGREES)C feasible over the commercial temperature range.

Hyperpolarization-activated current (I(h)) in vestibular calyx terminals: characterization and role in shaping postsynaptic events.

PubMed

Meredith, Frances L; Benke, Tim A; Rennie, Katherine J

2012-12-01

Calyx afferent terminals engulf the basolateral region of type I vestibular hair cells, and synaptic transmission across the vestibular type I hair cell/calyx is not well understood. Calyces express several ionic conductances, which may shape postsynaptic potentials. These include previously described tetrodotoxin-sensitive inward Na(+) currents, voltage-dependent outward K(+) currents and a K(Ca) current. Here, we characterize an inwardly rectifying conductance in gerbil semicircular canal calyx terminals (postnatal days 3-45), sensitive to voltage and to cyclic nucleotides. Using whole-cell patch clamp, we recorded from isolated calyx terminals still attached to their type I hair cells. A slowly activating, noninactivating current (I(h)) was seen with hyperpolarizing voltage steps negative to the resting potential. External Cs(+) (1-5 mM) and ZD7288 (100 μM) blocked the inward current by 97 and 83 %, respectively, confirming that I(h) was carried by hyperpolarization-activated, cyclic nucleotide gated channels. Mean half-activation voltage of I(h) was -123 mV, which shifted to -114 mV in the presence of cAMP. Activation of I(h) was well described with a third order exponential fit to the current (mean time constant of activation, τ, was 190 ms at -139 mV). Activation speeded up significantly (τ=136 and 127 ms, respectively) when intracellular cAMP and cGMP were present, suggesting that in vivo I(h) could be subject to efferent modulation via cyclic nucleotide-dependent mechanisms. In current clamp, hyperpolarizing current steps produced a time-dependent depolarizing sag followed by either a rebound afterdepolarization or an action potential. Spontaneous excitatory postsynaptic potentials (EPSPs) became larger and wider when I(h) was blocked with ZD7288. In a three-dimensional mathematical model of the calyx terminal based on Hodgkin-Huxley type ionic conductances, removal of I(h) similarly increased the EPSP, whereas cAMP slightly decreased simulated EPSP size and width.

Structural basis for signaling by exclusive EDS1 heteromeric complexes with SAG101 or PAD4 in plant innate immunity.

PubMed

Wagner, Stephan; Stuttmann, Johannes; Rietz, Steffen; Guerois, Raphael; Brunstein, Elena; Bautor, Jaqueline; Niefind, Karsten; Parker, Jane E

2013-12-11

Biotrophic plant pathogens encounter a postinfection basal resistance layer controlled by the lipase-like protein enhanced disease susceptibility 1 (EDS1) and its sequence-related interaction partners, senescence-associated gene 101 (SAG101) and phytoalexin deficient 4 (PAD4). Maintainance of separate EDS1 family member clades through angiosperm evolution suggests distinct functional attributes. We report the Arabidopsis EDS1-SAG101 heterodimer crystal structure with juxtaposed N-terminal α/β hydrolase and C-terminal α-helical EP domains aligned via a large conserved interface. Mutational analysis of the EDS1-SAG101 heterodimer and a derived EDS1-PAD4 structural model shows that EDS1 signals within mutually exclusive heterocomplexes. Although there is evolutionary conservation of α/β hydrolase topology in all three proteins, a noncatalytic resistance mechanism is indicated. Instead, the respective N-terminal domains appear to facilitate binding of the essential EP domains to create novel interaction surfaces on the heterodimer. Transitions between distinct functional EDS1 heterodimers might explain the central importance and versatility of this regulatory node in plant immunity. Copyright © 2013 Elsevier Inc. All rights reserved.

ISOLATION AND GENOTYPING OF Toxoplasma gondii IN SERONEGATIVE URBAN RATS AND PRESENCE OF ANTIBODIES IN COMMUNICATING DOGS IN BRAZIL

PubMed Central

RUFFOLO, Bruno Bergamo; TOLEDO, Roberta dos Santos; MARTINS, Felippe Danyel Cardoso; BUGNI, Felipe Monteiro; da COSTA, Letícia; MARANA, Elizabete Regina Marangoni; NAVARRO, Italmar Teodorico; GARCIA, João Luis; SU, Chunlei; FREIRE, Roberta Lemos

2016-01-01

The role of rodents in the epidemiology of toxoplasmosis was investigated in Londrina, Paraná State, Brazil. One hundred and eighty-one Rattus rattus and one Mus musculus were caught in 37 places. Blood and tissues were collected and submitted to the indirect fluorescence antibody test (IFAT) and the bioassay. Serum samples from 61 contacting dogs were also collected. Sixteen rats (8.8%) were positive for Toxoplasma gondii, but just two of them were positive by serology and bioassay test. Antibodies were found in nine (4.9%) rats. Tissues of nine rats bioassayed were positive and four isolates were obtained. Restriction fragment length polymorphism (RFLP) analysis was performed using 12 markers (SAG1, SAG2, SAG2-alt, C22-8, C29-2, L358, PK1, BTUB, GRA6, SAG3, Apico, CS3). Genotyping revealed that the four strains isolated from this study have been isolated before in cats and chickens from Brazil. None of the isolates was identified like clonal archetypal T-types I, II, and III. The rats presented lower serologic Toxoplasma gondii prevalence (8.8%) compared to contacting dogs (70.5%). PMID:27074322

First isolation and RFLP genotyping of Toxoplasma gondii from crab-eating fox (Cerdocyon thous-Linnaeus, 1766).

PubMed

de Almeida, Jonatas Campos; de Melo, Renata Pimentel Bandeira; de Morais Pedrosa, Camila; da Silva Santos, Marcelo; de Barros, Luiz Daniel; Garcia, João Luis; Porto, Wagnner José Nascimento; Mota, Rinaldo Aparecido

2017-05-01

Wild animals may play an important role in the transmission and maintenance of Toxoplasma gondii in the environment. The purpose of the present study was to isolate and genotype T. gondii from a free-ranging crab-eating fox (Cerdocyon thous-Linnaeus, 1766). A crab-eating fox in critical health condition was attended in a veterinary hospital in Recife, Pernambuco State, Brazil. The animal died despite emergency treatment. The brain was collected aseptically and destined for mouse bioassay. One isolate of T. gondii was obtained, and Polymerase Chain Reaction - Restriction Fragment Length Polymorphism (PCR-RFLP) was used to assess genetic variability at 11 markers (SAG1, SAG2, altSAG2, SAG3, BTUB, GRA6, c228, c292, L358, PK1 and APICO). A murine model was used to assess the virulence of the isolate. Using the PCR-RFLP, genotype ToxoDB #13 was identified, which is considered an atypical strain. The isolate was classified as avirulent in the murine model. This is the first study to report T. gondii infection in the crab-eating fox. Copyright © 2017 Elsevier B.V. All rights reserved.

Inter- and intramolecular epitope spreading in equine recurrent uveitis.

PubMed

Deeg, Cornelia A; Amann, Barbara; Raith, Albert J; Kaspers, Bernd

2006-02-01

To test the hypothesis that inter- and intramolecular spreading to S-antigen (S-Ag) and interphotoreceptor retinoid binding protein (IRBP)-derived epitopes occurs in a spontaneous model of recurrent uveitis in the horse. The immune response of eight horses with equine recurrent uveitis (ERU) was compared with that of five control horses with healthy eyes. Lymphocytes derived from peripheral blood (PBLs) were tested every 8 weeks for their reactivity against S-Ag and various S-Ag and IRBP-derived peptides for 12 to 39 months (median, 22 months). During uveitic episodes, additional blood samples were analyzed. Intermolecular epitope spreading was detectable in all ERU cases during the study. Intramolecular spreading occurred in seven (of eight) horses with ERU. Fourteen relapses were analyzed during the observation period. Ten uveitic episodes were accompanied by neoreactivity to S-Ag or IRBP-derived peptides during the relapse. Shifts in the immune response profile were also detectable without any clinical signs of inflammation. Eye-healthy control horses were negative at all time points in the in vitro proliferation assays. Inter- and intramolecular spreading was detectable in a spontaneous model of recurrent uveitis. The shifts in immunoreactivity could account for the remitting-relapsing character of the disease.

TRIAC/SCR proportional control circuit

DOEpatents

Hughes, W.J.

1999-04-06

A power controller device is disclosed which uses a voltage-to-frequency converter in conjunction with a zero crossing detector to linearly and proportionally control AC power being supplied to a load. The output of the voltage-to frequency converter controls the ``reset`` input of a R-S flip flop, while an ``0`` crossing detector controls the ``set`` input. The output of the flip flop triggers a monostable multivibrator controlling the SCR or TRIAC firing circuit connected to the load. Logic gates prevent the direct triggering of the multivibrator in the rare instance where the ``reset`` and ``set`` inputs of the flip flop are in coincidence. The control circuit can be supplemented with a control loop, providing compensation for line voltage variations. 9 figs.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chinthavali, Madhu Sudhan; Wang, Zhiqiang

This paper presents a detailed parametric sensitivity analysis for a wireless power transfer (WPT) system in electric vehicle application. Specifically, several key parameters for sensitivity analysis of a series-parallel (SP) WPT system are derived first based on analytical modeling approach, which includes the equivalent input impedance, active / reactive power, and DC voltage gain. Based on the derivation, the impact of primary side compensation capacitance, coupling coefficient, transformer leakage inductance, and different load conditions on the DC voltage gain curve and power curve are studied and analyzed. It is shown that the desired power can be achieved by just changingmore » frequency or voltage depending on the design value of coupling coefficient. However, in some cases both have to be modified in order to achieve the required power transfer.« less

The Multi-SAG project: filling the MultiDark simulations with semi-analytic galaxies

NASA Astrophysics Data System (ADS)

Vega-Martínez, C. A.; Cora, S. A.; Padilla, N. D.; Muñoz Arancibia, A. M.; Orsi, A. A.; Ruiz, A. N.

2016-08-01

The semi-analytical model sag is a code of galaxy formation and evolution which is applied to halo catalogs and merger trees extracted from cosmological -body simulations of dark matter. This contribution describes the project of constructing a catalog of simulated galaxies by adapting and applying the model sag over two dark matter simulations of the spanish MultiDark Project publicly available. Those simulations have particles, each, in boxes with sizes of 1000 Mpc and 400 Mpc respectively with Planck cosmological parameters. They cover a large range of masses and have halo mass resolutions of , therefore each simulation is able to produce more than 150 millions of simulated galaxies. A detailed description of the method is explained, and the first statistical results are shown.

Mitigation of Power Quality Problems in Grid-Interactive Distributed Generation System

NASA Astrophysics Data System (ADS)

Bhende, C. N.; Kalam, A.; Malla, S. G.

2016-04-01

Having an inter-tie between low/medium voltage grid and distributed generation (DG), both exposes to power quality (PQ) problems created by each other. This paper addresses various PQ problems arise due to integration of DG with grid. The major PQ problems are due to unbalanced and non-linear load connected at DG, unbalanced voltage variations on transmission line and unbalanced grid voltages which severely affect the performance of the system. To mitigate the above mentioned PQ problems, a novel integrated control of distribution static shunt compensator (DSTATCOM) is presented in this paper. DSTATCOM control helps in reducing the unbalance factor of PCC voltage. It also eliminates harmonics from line currents and makes them balanced. Moreover, DSTATCOM supplies the reactive power required by the load locally and hence, grid need not to supply the reactive power. To show the efficacy of the proposed controller, several operating conditions are considered and verified through simulation using MATLAB/SIMULINK.

An Optimal Control Strategy for DC Bus Voltage Regulation in Photovoltaic System with Battery Energy Storage

PubMed Central

Daud, Muhamad Zalani; Mohamed, Azah; Hannan, M. A.

2014-01-01

This paper presents an evaluation of an optimal DC bus voltage regulation strategy for grid-connected photovoltaic (PV) system with battery energy storage (BES). The BES is connected to the PV system DC bus using a DC/DC buck-boost converter. The converter facilitates the BES power charge/discharge to compensate for the DC bus voltage deviation during severe disturbance conditions. In this way, the regulation of DC bus voltage of the PV/BES system can be enhanced as compared to the conventional regulation that is solely based on the voltage-sourced converter (VSC). For the grid side VSC (G-VSC), two control methods, namely, the voltage-mode and current-mode controls, are applied. For control parameter optimization, the simplex optimization technique is applied for the G-VSC voltage- and current-mode controls, including the BES DC/DC buck-boost converter controllers. A new set of optimized parameters are obtained for each of the power converters for comparison purposes. The PSCAD/EMTDC-based simulation case studies are presented to evaluate the performance of the proposed optimized control scheme in comparison to the conventional methods. PMID:24883374

An optimal control strategy for DC bus voltage regulation in photovoltaic system with battery energy storage.

PubMed

Daud, Muhamad Zalani; Mohamed, Azah; Hannan, M A

2014-01-01

This paper presents an evaluation of an optimal DC bus voltage regulation strategy for grid-connected photovoltaic (PV) system with battery energy storage (BES). The BES is connected to the PV system DC bus using a DC/DC buck-boost converter. The converter facilitates the BES power charge/discharge to compensate for the DC bus voltage deviation during severe disturbance conditions. In this way, the regulation of DC bus voltage of the PV/BES system can be enhanced as compared to the conventional regulation that is solely based on the voltage-sourced converter (VSC). For the grid side VSC (G-VSC), two control methods, namely, the voltage-mode and current-mode controls, are applied. For control parameter optimization, the simplex optimization technique is applied for the G-VSC voltage- and current-mode controls, including the BES DC/DC buck-boost converter controllers. A new set of optimized parameters are obtained for each of the power converters for comparison purposes. The PSCAD/EMTDC-based simulation case studies are presented to evaluate the performance of the proposed optimized control scheme in comparison to the conventional methods.

Geology, thermal maturation, and source rock geochemistry in a volcanic covered basin: San Juan sag, south-central Colorado

USGS Publications Warehouse

Gries, R.R.; Clayton, J.L.; Leonard, C.

1997-01-01

The San Juan sag, concealed by the vast San Juan volcanic field of south-central Colorado, has only recently benefited from oil and gas wildcat drilling and evaluations. Sound geochemical analyses and maturation modeling are essential elements for successful exploration and development. Oil has been produced in minor quantities from an Oligocene sill in the Mancos Shale within the sag, and major oil and gas production occurs from stratigraphically equivalent rocks in the San Juan basin to the south-west and in the Denver basin to the northeast. The objectives of this study were to identify potential source rocks, assess thermal maturity, and determine hydrocarbon-source bed relationships. Source rocks are present in the San Juan sag in the upper and lower Mancos Shale (including the Niobrara Member), which consists of about 666 m (2184 ft) of marine shale with from 0.5 to 3.1 wt. % organic carbon. Pyrolysis yields (S1 + S2 = 2000-6000 ppm) and solvent extraction yields (1000-4000 ppm) indicate that some intervals within the Mancos Shale are good potential source rocks for oil, containing type II organic matter, according to Rock-Eval pyrolysis assay. Oils produced from the San Juan sag and adjacent part of the San Juan basin are geochemically similar to rock extracts obtained from these potential source rock intervals. Based on reconstruction of the geologic history of the basin integrated with models of organic maturation, we conclude that most of the source rock maturation occurred in the Oligocene and Miocene. Little to no maturation took place during Laramide subsidence of the basin, when the Animas and Blanco Basin formations were deposited. The timing of maturation is unlike that of most Laramide basins in the Rocky Mountain region, where maturation occurred as a result of Paleocene and Eocene basin fill. The present geothermal gradient in the San Juan sag is slightly higher (average 3.5??C/100 m; 1.9??F/100 ft) than the regional average for southern Rocky Mountain basins; however, although the sag contains intrusives and a volcanic cover, the gradient is significantly lower than that reported for parts of the adjacent San Juan basin (4.7??C/100 m; 2.6??F/100 ft). Burial depth appears to be a more important controlling factor in the thermal history of the source rocks than local variations in the geothermal gradient due to volcanic activity. Interestingly, the thick overburden of volcanic rocks appears to have provided the necessary burial depth for maturation.

Publications - GMC 384 | Alaska Division of Geological & Geophysical

Science.gov Websites

Bay St #13-09-19, W Mikkelsen St #1, and Sag River St #1, Lisburne to total depth Authors: Boyer, D , Thin section photomicrographs and descriptions for Mikkelsen Bay St #13-09-19, W Mikkelsen St #1, and Sag River St #1, Lisburne to total depth: Alaska Division of Geological & Geophysical Surveys

Concept of Operations for the ESC Product Line Approach.

DTIC Science & Technology

1996-08-30

production of the application. Product Line Engineering Center ( PLEC ) defines and evolves product line architectures with the SAG. The PLEC is also tasked... PLEC , SAG, and PLAS and offers scenarios for asset and system development. • Section 4 outlines the ESC Product Line transition strategy. • Section...Line or System Needs User Select PLEC ; Assess PL architecture Product Line Architecture Development ments; architecture selection Architecture

A High Frequency Active Voltage Doubler in Standard CMOS Using Offset-Controlled Comparators for Inductive Power Transmission

PubMed Central

Lee, Hyung-Min; Ghovanloo, Maysam

2014-01-01

In this paper, we present a fully integrated active voltage doubler in CMOS technology using offset-controlled high speed comparators for extending the range of inductive power transmission to implantable microelectronic devices (IMD) and radio-frequency identification (RFID) tags. This active voltage doubler provides considerably higher power conversion efficiency (PCE) and lower dropout voltage compared to its passive counterpart and requires lower input voltage than active rectifiers, leading to reliable and efficient operation with weakly coupled inductive links. The offset-controlled functions in the comparators compensate for turn-on and turn-off delays to not only maximize the forward charging current to the load but also minimize the back current, optimizing PCE in the high frequency (HF) band. We fabricated the active voltage doubler in a 0.5-μm 3M2P std. CMOS process, occupying 0.144 mm2 of chip area. With 1.46 V peak AC input at 13.56 MHz, the active voltage doubler provides 2.4 V DC output across a 1 kΩ load, achieving the highest PCE = 79% ever reported at this frequency. In addition, the built-in start-up circuit ensures a reliable operation at lower voltages. PMID:23853321

Reversible voltage dependent transition of abnormal and normal bipolar resistive switching.

PubMed

Wang, Guangyu; Li, Chen; Chen, Yan; Xia, Yidong; Wu, Di; Xu, Qingyu

2016-11-14

Clear understanding the mechanism of resistive switching is the important prerequisite for the realization of high performance nonvolatile resistive random access memory. In this paper, binary metal oxide MoO x layer sandwiched by ITO and Pt electrodes was taken as a model system, reversible transition of abnormal and normal bipolar resistive switching (BRS) in dependence on the maximum voltage was observed. At room temperature, below a critical maximum voltage of 2.6 V, butterfly shaped I-V curves of abnormal BRS has been observed with low resistance state (LRS) to high resistance state (HRS) transition in both polarities and always LRS at zero field. Above 2.6 V, normal BRS was observed, and HRS to LRS transition happened with increasing negative voltage applied. Temperature dependent I-V measurements showed that the critical maximum voltage increased with decreasing temperature, suggesting the thermal activated motion of oxygen vacancies. Abnormal BRS has been explained by the partial compensation of electric field from the induced dipoles opposite to the applied voltage, which has been demonstrated by the clear amplitude-voltage and phase-voltage hysteresis loops observed by piezoelectric force microscopy. The normal BRS was due to the barrier modification at Pt/MoO x interface by the accumulation and depletion of oxygen vacancies.

The clinical features of respiratory infections caused by the Streptococcus anginosus group.

PubMed

Noguchi, Shingo; Yatera, Kazuhiro; Kawanami, Toshinori; Yamasaki, Kei; Naito, Keisuke; Akata, Kentaro; Shimabukuro, Ikuko; Ishimoto, Hiroshi; Yoshii, Chiharu; Mukae, Hiroshi

2015-10-26

The Streptococcus anginosus group (SAG) play important roles in respiratory infections. It is ordinarily difficult to distinguish them from contaminations as the causative pathogens of respiratory infections because they are often cultured in respiratory specimens. Therefore, it is important to understand the clinical characteristics and laboratory findings of respiratory infections caused by the SAG members. The aim of this study is to clarify the role of the SAG bacteria in respiratory infections. A total of 30 patients who were diagnosed with respiratory infections which were caused by the SAG bacteria between January 2005 and February 2015 were retrospectively evaluated. Respiratory infections caused by the SAG were mostly seen in male patients with comorbid diseases and were typically complicated with pleural effusion. Pleural effusion was observed in 22 (73.3%) patients. Empyema was observed in half of the 22 patients with pleural effusion. S. intermedius, S. constellatus and S. anginosus were detected in 16 (53.3 %), 11 (36.7 %) and 3 (10.0 %) patients, respectively. Six patients had mixed-infections. The duration from the onset of symptoms to the hospital visit was significantly longer in "lung abscess" patients than in "pneumonia" patients among the 24 patients with single infections, but not among the six patients with mixed-infection. The peripheral white blood cell counts of the "pneumonia" patients were higher than those of the "lung abscess" patients and S. intermedius was identified significantly more frequently in patients with pulmonary and pleural infections (pneumonia and lung abscess) than in patients with bacterial pleurisy only. In addition, the patients in whom S. intermedius was cultured were significantly older than those in whom S. constellatus was cultured. Respiratory infections caused by the SAG bacteria tended to be observed more frequently in male patients with comorbid diseases and to more frequently involve purulent formation. In addition, S. intermedius was mainly identified in elderly patients with having pulmonary infection complicated with pleural effusion, and the aspiration of oral secretions may be a risk factor in the formation of empyema thoracis associated with pneumonia due to S. intermedius.

Comparative Single-Cell Genomics of Chloroflexi from the Okinawa Trough Deep-Subsurface Biosphere.

PubMed

Fullerton, Heather; Moyer, Craig L

2016-05-15

Chloroflexi small-subunit (SSU) rRNA gene sequences are frequently recovered from subseafloor environments, but the metabolic potential of the phylum is poorly understood. The phylum Chloroflexi is represented by isolates with diverse metabolic strategies, including anoxic phototrophy, fermentation, and reductive dehalogenation; therefore, function cannot be attributed to these organisms based solely on phylogeny. Single-cell genomics can provide metabolic insights into uncultured organisms, like the deep-subsurface Chloroflexi Nine SSU rRNA gene sequences were identified from single-cell sorts of whole-round core material collected from the Okinawa Trough at Iheya North hydrothermal field as part of Integrated Ocean Drilling Program (IODP) expedition 331 (Deep Hot Biosphere). Previous studies of subsurface Chloroflexi single amplified genomes (SAGs) suggested heterotrophic or lithotrophic metabolisms and provided no evidence for growth by reductive dehalogenation. Our nine Chloroflexi SAGs (seven of which are from the order Anaerolineales) indicate that, in addition to genes for the Wood-Ljungdahl pathway, exogenous carbon sources can be actively transported into cells. At least one subunit for pyruvate ferredoxin oxidoreductase was found in four of the Chloroflexi SAGs. This protein can provide a link between the Wood-Ljungdahl pathway and other carbon anabolic pathways. Finally, one of the seven Anaerolineales SAGs contains a distinct reductive dehalogenase homologous (rdhA) gene. Through the use of single amplified genomes (SAGs), we have extended the metabolic potential of an understudied group of subsurface microbes, the Chloroflexi These microbes are frequently detected in the subsurface biosphere, though their metabolic capabilities have remained elusive. In contrast to previously examined Chloroflexi SAGs, our genomes (several are from the order Anaerolineales) were recovered from a hydrothermally driven system and therefore provide a unique window into the metabolic potential of this type of habitat. In addition, a reductive dehalogenase gene (rdhA) has been directly linked to marine subsurface Chloroflexi, suggesting that reductive dehalogenation is not limited to the class Dehalococcoidia This discovery expands the nutrient-cycling and metabolic potential present within the deep subsurface and provides functional gene information relating to this enigmatic group. Copyright © 2016 Fullerton and Moyer.

Passive Resistor Temperature Compensation for a High-Temperature Piezoresistive Pressure Sensor.

PubMed

Yao, Zong; Liang, Ting; Jia, Pinggang; Hong, Yingping; Qi, Lei; Lei, Cheng; Zhang, Bin; Li, Wangwang; Zhang, Diya; Xiong, Jijun

2016-07-22

The main limitation of high-temperature piezoresistive pressure sensors is the variation of output voltage with operating temperature, which seriously reduces their measurement accuracy. This paper presents a passive resistor temperature compensation technique whose parameters are calculated using differential equations. Unlike traditional experiential arithmetic, the differential equations are independent of the parameter deviation among the piezoresistors of the microelectromechanical pressure sensor and the residual stress caused by the fabrication process or a mismatch in the thermal expansion coefficients. The differential equations are solved using calibration data from uncompensated high-temperature piezoresistive pressure sensors. Tests conducted on the calibrated equipment at various temperatures and pressures show that the passive resistor temperature compensation produces a remarkable effect. Additionally, a high-temperature signal-conditioning circuit is used to improve the output sensitivity of the sensor, which can be reduced by the temperature compensation. Compared to traditional experiential arithmetic, the proposed passive resistor temperature compensation technique exhibits less temperature drift and is expected to be highly applicable for pressure measurements in harsh environments with large temperature variations.

Passive Resistor Temperature Compensation for a High-Temperature Piezoresistive Pressure Sensor

PubMed Central

Yao, Zong; Liang, Ting; Jia, Pinggang; Hong, Yingping; Qi, Lei; Lei, Cheng; Zhang, Bin; Li, Wangwang; Zhang, Diya; Xiong, Jijun

2016-01-01

The main limitation of high-temperature piezoresistive pressure sensors is the variation of output voltage with operating temperature, which seriously reduces their measurement accuracy. This paper presents a passive resistor temperature compensation technique whose parameters are calculated using differential equations. Unlike traditional experiential arithmetic, the differential equations are independent of the parameter deviation among the piezoresistors of the microelectromechanical pressure sensor and the residual stress caused by the fabrication process or a mismatch in the thermal expansion coefficients. The differential equations are solved using calibration data from uncompensated high-temperature piezoresistive pressure sensors. Tests conducted on the calibrated equipment at various temperatures and pressures show that the passive resistor temperature compensation produces a remarkable effect. Additionally, a high-temperature signal-conditioning circuit is used to improve the output sensitivity of the sensor, which can be reduced by the temperature compensation. Compared to traditional experiential arithmetic, the proposed passive resistor temperature compensation technique exhibits less temperature drift and is expected to be highly applicable for pressure measurements in harsh environments with large temperature variations. PMID:27455271

Adaptive piezoelectric sensoriactuator

NASA Technical Reports Server (NTRS)

Clark, Jr., Robert L. (Inventor); Vipperman, Jeffrey S. (Inventor); Cole, Daniel G. (Inventor)

1996-01-01

An adaptive algorithm implemented in digital or analog form is used in conjunction with a voltage controlled amplifier to compensate for the feedthrough capacitance of piezoelectric sensoriactuator. The mechanical response of the piezoelectric sensoriactuator is resolved from the electrical response by adaptively altering the gain imposed on the electrical circuit used for compensation. For wideband, stochastic input disturbances, the feedthrough capacitance of the sensoriactuator can be identified on-line, providing a means of implementing direct-rate-feedback control in analog hardware. The device is capable of on-line system health monitoring since a quasi-stable dynamic capacitance is indicative of sustained health of the piezoelectric element.

Note: Wide band amplifier for quartz tuning fork sensors with digitally controlled stray capacitance compensation.

PubMed

Peng, Ping; Hao, Lifeng; Ding, Ning; Jiao, Weicheng; Wang, Qi; Zhang, Jian; Wang, Rongguo

2015-11-01

We presented a preamplifier design for quartz tuning fork (QTF) sensors in which the stray capacitance is digitally compensated. In this design, the manually controlled variable capacitor is replaced by a pair of varicap diodes, whose capacitance could be accurately tuned by a bias voltage. A tuning circuit including a single side low power operational amplifier, a digital-to-analog converter, and a microprocessor is also described, and the tuning process can be conveniently carried out on a personal computer. For the design, the noise level was investigated experimentally.

Measurement of beam divergence of 30-centimeter dished grids

NASA Technical Reports Server (NTRS)

Danilowicz, R. L.; Rawlin, V. K.; Banks, B. A.; Wintucky, E. G.

1973-01-01

The beam divergence of a 30-centimeter diameter thruster with dished grids was calculated from current densities measured with a probe rake containing seventeen planar molybdenum probes. The measured data were analyzed as a function of a number of parameters. The most sensitive parameters were the amount of compensation of the accelerator grid and the ratio of net to total accelerating voltage. The thrust losses were reduced by over 5 percent with the use of compensated grids alone, and by variation of other parameters the overall thrust losses due to beam divergence were reduced to less than 2 percent.

Measurement of beam divergence of 30-centimeter dished grids

NASA Technical Reports Server (NTRS)

Danilowicz, R. L.; Rawlin, V. K.; Banks, B. A.; Wintucky, E. G.

1973-01-01

The beam divergence of a 30-centimeter diameter thrustor with dished grids was calculated from current densities measured with a probe rake containing seventeen planar molybdenum probes. The measured data were analyzed as a function of a number of parameters. The most sensitive parameters were the amount of compensation of the accelerator grid and the ratio of net to total accelerating voltage. The thrust losses were reduced by over 5 percent with the use of compensated grids alone, and by variation of other parameters the overall thrust losses due to beam divergence were reduced to less than 2 percent.

Second-order sliding mode control for DFIG-based wind turbines fault ride-through capability enhancement.

PubMed

Benbouzid, Mohamed; Beltran, Brice; Amirat, Yassine; Yao, Gang; Han, Jingang; Mangel, Hervé

2014-05-01

This paper deals with the fault ride-through capability assessment of a doubly fed induction generator-based wind turbine using a high-order sliding mode control. Indeed, it has been recently suggested that sliding mode control is a solution of choice to the fault ride-through problem. In this context, this paper proposes a second-order sliding mode as an improved solution that handle the classical sliding mode chattering problem. Indeed, the main and attractive features of high-order sliding modes are robustness against external disturbances, the grids faults in particular, and chattering-free behavior (no extra mechanical stress on the wind turbine drive train). Simulations using the NREL FAST code on a 1.5-MW wind turbine are carried out to evaluate ride-through performance of the proposed high-order sliding mode control strategy in case of grid frequency variations and unbalanced voltage sags. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Antibody Detection and Molecular Characterization of Toxoplasma gondii from Bobcats (Lynx rufus), Domestic Cats (Felis catus), and Wildlife from Minnesota, USA.

PubMed

Verma, Shiv K; Minicucci, Larissa; Murphy, Darby; Carstensen, Michelle; Humpal, Carolin; Wolf, Paul; Calero-Bernal, Rafael; Cerqueira-Cézar, Camila K; Kwok, Oliver C H; Su, Chunlei; Hill, Dolores; Dubey, Jitender P

2016-09-01

Little is known of the epidemiology of toxoplasmosis in Minnesota. Here, we evaluated Toxoplasma gondii infection in 50 wild bobcats (Lynx rufus) and 75 other animals on/near 10 cattle farms. Antibodies to T. gondii were assayed in serum samples or tissue fluids by the modified agglutination test (MAT, cut-off 1:25). Twenty nine of 50 bobcats and 15 of 41 wildlife trapped on the vicinity of 10 farms and nine of 16 adult domestic cats (Felis catus) and six of 14 domestic dogs resident on farms were seropositive. Toxoplasma gondii oocysts were not found in feces of any felid. Tissues of all seropositive wild animals trapped on the farm were bioassayed in mice and viable T. gondii was isolated from two badgers (Taxidea taxus), two raccoons (Procyon lotor), one coyote (Canis latrans), and one opossum (Didelphis virginiana). All six T. gondii isolates were further propagated in cell culture. Multi-locus PCR-RFLP genotyping using 10 markers (SAG1, SAG2 (5'-3'SAG2, and alt.SAG2), SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico), and DNA from cell culture derived tachyzoites revealed three genotypes; #5 ToxoDataBase (1 coyote, 1 raccoon), #1 (1 badger, 1 raccoon, 1 opossum), and #2 (1 badger). This is the first report of T. gondii prevalence in domestic cats and in bobcats from Minnesota, and the first isolation of viable T. gondii from badger. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

Protein accumulation in leaves and roots associated with improved drought tolerance in creeping bentgrass expressing an ipt gene for cytokinin synthesis

PubMed Central

Merewitz, Emily B.; Gianfagna, Thomas; Huang, Bingru

2011-01-01

Cytokinins (CKs) may be involved in the regulation of plant adaptation to drought stress. The objectives of the study were to identify proteomic changes in leaves and roots in relation to improved drought tolerance in transgenic creeping bentgrass (Agrostis stolonifera) containing a senescence-activated promoter (SAG12) and the isopentyl transferase (ipt) transgene that increases endogenous CK content. Leaves of SAG12-ipt bentgrass exhibited less severe senescence under water stress, as demonstrated by maintaining lower electrolyte leakage and lipid peroxidation, and higher photochemical efficiency (Fv/Fm), compared with the null transformant (NT) plants. SAG12-ipt plants had higher root/shoot ratios and lower lipid peroxidation in leaves under water stress than the NT plants. The suppression of drought-induced leaf senescence and root dieback in the transgenic plants was associated with the maintenance of greater antioxidant enzyme activities (superoxide dismutase, peroxidase, and catalase). The SAG12-ipt and NT plants exhibited differential protein expression patterns under well-watered and drought conditions in both leaves and roots. Under equivalent leaf water deficit (47% relative water content), SAG12-ipt plants maintained higher abundance of proteins involved in (i) energy production within both photosynthesis and respiration [ribulose 1,5-bisphosphate carboxylase (RuBisCO) and glyceraldehyde phosphate dehydrogenase (GAPDH)]; (ii) amino acid synthesis (methionine and glutamine); (iii) protein synthesis and destination [chloroplastic elongation factor (EF-Tu) and protein disulphide isomerases (PDIs)]; and (iv) antioxidant defence system (catalase and peroxidase) than the NT plants. These results suggest that increased endogenous CKs under drought stress may directly or indirectly regulate protein abundance and enzymatic activities involved in the above-mentioned metabolic processes, thereby enhancing plant drought tolerance. PMID:21831843

First isolation and genotyping of Toxoplasma gondii from bats (Mammalia: Chiroptera).

PubMed

Cabral, A D; Gama, A R; Sodré, M M; Savani, E S M M; Galvão-Dias, M A; Jordão, L R; Maeda, M M; Yai, L E O; Gennari, S M; Pena, H F J

2013-03-31

There are currently no reports on the isolation and molecular examination of Toxoplasma gondii from bats. Here, we report the isolation and genotypic characterisation of two T. gondii isolates from bats. A total of 369 bats from different municipalities in São Paulo state, southeastern Brazil, were captured and euthanised, and collected tissues (heart and pectoral muscle) were processed for each bat or in pools of two or three bats and bioassayed in mice (a total of 283 bioassays). Eleven PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) markers were used to genotype positive samples: SAG1, SAG2 (5'-3'SAG2 and alt. SAG2), SAG3, BTUB, GRA6, L358, c22-8, c29-2, PK1, CS3 and Apico. The parasite was isolated from two bats from São Paulo city: an insectivorous bat, the velvety free-tailed bat Molossus molossus, and a hematophagous bat, the common vampire bat Desmodus rotundus. Isolates were designated TgBatBr1 and TgBatBr2, respectively. The genotype of the isolate from M. molossus (TgBatBr1) has been previously described in an isolate from a capybara from São Paulo state, and the genotype from the D. rotundus isolate (TgBatBr2) has already been identified in isolates from cats, chickens, capybaras, sheep, a rodent and a common rabbit from different Brazilian states, suggesting that this may be a common T. gondii lineage circulating in some Brazilian regions. Isolation of T. gondii from a hematophagous species is striking. This study reveals that bats can share the same isolates that are found in domesticated and wild terrestrial animals. This is the first report of the isolation and genotyping of T. gondii in chiropterans. Copyright © 2012 Elsevier B.V. All rights reserved.

Deconvolution of Composition and Crystallite Size of Silver Hollandite Nanorods: Influence on Electrochemistry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Durham, Jessica L.; Huang, Jianping; Zhang, Bingjie

In this paper, silver hollandite (Ag 1.4Mn 8O 16) has been synthesized by an aqueous, low-temperature co-precipitation technique to afford silver hollandite with distinct crystallite sizes (10 and 15 nm, identified as S-Ag 1.4Mn 8O 16 and L-Ag 1.4Mn 8O 16, respectively) and equivalent silver content (x), allowing for the deconvolution of electrochemical effects related to crystallite size and silver content. The as-prepared silver hollandite materials were confirmed to be structurally analogous. Notably, TEM imaging reveals a high degree of bundling of S-Ag 1.4Mn 8O 16 nanorods compared to L-Ag 1.4Mn 8O 16 which facilitates more intimate connection of themore » S-Ag 1.4Mn 8O 16 material with enhanced interparticle contact. The electrochemical behavior and lithium diffusion properties were investigated by galvanostatic cycling, CV, electrochemical impedance, pulsed-discharge experiments, and ex-situ XAS analysis of cycled cathodes. Lithium based electrochemical cells containing S-Ag 1.4Mn 8O 16 delivered a capacity 15X higher than L-Ag 1.4Mn 8O 16 on cycle 1. Ex-situ XAS demonstrated structural change for S-Ag 1.4Mn 8O 16 and formation of Ag 0 on insertion of 3.8 Li + intercalation. However, the samples of L-Ag 1.4Mn 8O 16 were lithiated by a more limited 0.25 molar equivalents, where no significant structural changes were observed. Finally, the findings affirm crystallite size significantly impacts electrochemistry independent of cation occupancy of the α-MnO 2 type structure.« less

Systemic Inflammatory Response Elicited by Superantigen Destabilizes T Regulatory Cells Rendering them Ineffective during Toxic Shock Syndrome 1

PubMed Central

Tilahun, Ashenafi Y.; Chowdhary, Vaidehi R.; David, Chella S.; Rajagopalan, Govindarajan

2014-01-01

Life-threatening infections caused by Staphylococcus aureus, particularly the community-acquired methicillin-resistant strains of S. aureus (CA-MRSA), continue to pose serious problems. Greater virulence and increased pathogenicity of certain S. aureus strains are attributed to higher prevalence of exotoxins. Of these exotoxins, the superantigens (SAg) are likely most pathogenic because of their ability to rapidly and robustly activate the T cells even in extremely small quantities. Therefore, countering SAg-mediated T cell activation using T regulatory cells (Tregs) might be beneficial in diseases such as toxic shock syndrome (TSS). As the normal numbers of endogenous Tregs in a typical host are insufficient, we hypothesized that increasing the Treg numbers by administration of IL2-anti-IL2 antibody complexes (IL2C) or by adoptive transfer of ex vivo expanded Tregs might be more effective in countering SAg-mediated immune activation. HLA-DR3 transgenic mice that closely recapitulate human TSS, were treated with IL2C to increase endogenous Tregs or received ex vivo expanded Tregs. Subsequently, they were challenged with SAg to induce TSS. Analyses of various parameters reflective of TSS (serum cytokine/chemokine levels, multiple organ pathology and SAg-induced peripheral T cell expansion) indicated that increasing the Tregs failed to mitigate TSS. On the contrary, serum IFN-γ levels were increased in IL2C treated mice. Exploration into the reasons behind the lack of protective effect of Tregs revealed IL-17 and IFN-γ-dependent loss of Tregs during TSS. In addition, significant upregulation of GITR on conventional T cells during TSS could render them resistant to Treg mediated suppression, contributing to failure of Treg-mediated immune regulation. PMID:25092888

Assessment of frontal lobe sagging after endoscopic endonasal transcribriform resection of anterior skull base tumors: is rigid structural reconstruction of the cranial base defect necessary?

PubMed

Eloy, Jean Anderson; Shukla, Pratik A; Choudhry, Osamah J; Singh, Rahul; Liu, James K

2012-12-01

The endoscopic endonasal transcribriform approach (EETA) is a viable alternative option for resection of selected anterior skull base (ASB) tumors. However, this technique results in the creation of large cribriform defects. Some have reported the use of a rigid substitute for ASB reconstruction to prevent postoperative frontal lobe sagging. We evaluate the degree of frontal lobe sagging using our triple-layer technique [fascia lata, acellular dermal allograft, and pedicled nasoseptal flap (PNSF)] without the use of rigid structural reconstruction for large cribriform defects. Retrospective analysis. Nine patients underwent an EETA for resection of large ASB tumors from August 2010 to November 2011. The degree of frontal lobe displacement after EETA, defined as the ASB position, was calculated based on the most inferior position of the frontal lobe relative to the nasion-sellar line defined on preoperative and postoperative imaging. A positive value signified upward displacement, and a negative value represented inferior displacement of the frontal lobe. The average cribriform defect size was 9.3 cm(2) (range, 5.0-13.8 cm(2) ). The average distance of postoperative frontal lobe displacement was 0.2 mm (range, -3.9 to 2.9 mm) without any cases of significant brain sagging. The mean follow-up period was 10.1 months (range, 4-19 months). There were no postoperative CSF leaks. Rigid structural repair may not be necessary for ASB defect repair after endoscopic endonasal resection of the cribriform plate. Our technique for multilayer cranial base reconstruction appears to be satisfactory in preventing delayed frontal lobe sagging. Copyright © 2012 The American Laryngological, Rhinological, and Otological Society, Inc.

A Novel Dominant Mutation in SAG, the Arrestin-1 Gene, Is a Common Cause of Retinitis Pigmentosa in Hispanic Families in the Southwestern United States

PubMed Central

Sullivan, Lori S.; Bowne, Sara J.; Koboldt, Daniel C.; Cadena, Elizabeth L.; Heckenlively, John R.; Branham, Kari E.; Wheaton, Dianna H.; Jones, Kaylie D.; Ruiz, Richard S.; Pennesi, Mark E.; Yang, Paul; Davis-Boozer, David; Northrup, Hope; Gurevich, Vsevold V.; Chen, Rui; Xu, Mingchu; Li, Yumei; Birch, David G.; Daiger, Stephen P.

2017-01-01

Purpose To identify the causes of autosomal dominant retinitis pigmentosa (adRP) in a cohort of families without mutations in known adRP genes and consequently to characterize a novel dominant-acting missense mutation in SAG. Methods Patients underwent ophthalmologic testing and were screened for mutations using targeted-capture and whole-exome next-generation sequencing. Confirmation and additional screening were done by Sanger sequencing. Haplotypes segregating with the mutation were determined using short tandem repeat and single nucleotide variant polymorphisms. Genealogies were established by interviews of family members. Results Eight families in a cohort of 300 adRP families, and four additional families, were found to have a novel heterozygous mutation in the SAG gene, c.440G>T; p.Cys147Phe. Patients exhibited symptoms of retinitis pigmentosa and none showed symptoms characteristic of Oguchi disease. All families are of Hispanic descent and most were ascertained in Texas or California. A single haplotype including the SAG mutation was identified in all families. The mutation dramatically alters a conserved amino acid, is extremely rare in global databases, and was not found in 4000+ exomes from Hispanic controls. Molecular modeling based on the crystal structure of bovine arrestin-1 predicts protein misfolding/instability. Conclusions This is the first dominant-acting mutation identified in SAG, a founder mutation possibly originating in Mexico several centuries ago. The phenotype is clearly adRP and is distinct from the previously reported phenotypes of recessive null mutations, that is, Oguchi disease and recessive RP. The mutation accounts for 3% of the 300 families in the adRP Cohort and 36% of Hispanic families in this cohort. PMID:28549094

A Novel Dominant Mutation in SAG, the Arrestin-1 Gene, Is a Common Cause of Retinitis Pigmentosa in Hispanic Families in the Southwestern United States.

PubMed

Sullivan, Lori S; Bowne, Sara J; Koboldt, Daniel C; Cadena, Elizabeth L; Heckenlively, John R; Branham, Kari E; Wheaton, Dianna H; Jones, Kaylie D; Ruiz, Richard S; Pennesi, Mark E; Yang, Paul; Davis-Boozer, David; Northrup, Hope; Gurevich, Vsevold V; Chen, Rui; Xu, Mingchu; Li, Yumei; Birch, David G; Daiger, Stephen P

2017-05-01

To identify the causes of autosomal dominant retinitis pigmentosa (adRP) in a cohort of families without mutations in known adRP genes and consequently to characterize a novel dominant-acting missense mutation in SAG. Patients underwent ophthalmologic testing and were screened for mutations using targeted-capture and whole-exome next-generation sequencing. Confirmation and additional screening were done by Sanger sequencing. Haplotypes segregating with the mutation were determined using short tandem repeat and single nucleotide variant polymorphisms. Genealogies were established by interviews of family members. Eight families in a cohort of 300 adRP families, and four additional families, were found to have a novel heterozygous mutation in the SAG gene, c.440G>T; p.Cys147Phe. Patients exhibited symptoms of retinitis pigmentosa and none showed symptoms characteristic of Oguchi disease. All families are of Hispanic descent and most were ascertained in Texas or California. A single haplotype including the SAG mutation was identified in all families. The mutation dramatically alters a conserved amino acid, is extremely rare in global databases, and was not found in 4000+ exomes from Hispanic controls. Molecular modeling based on the crystal structure of bovine arrestin-1 predicts protein misfolding/instability. This is the first dominant-acting mutation identified in SAG, a founder mutation possibly originating in Mexico several centuries ago. The phenotype is clearly adRP and is distinct from the previously reported phenotypes of recessive null mutations, that is, Oguchi disease and recessive RP. The mutation accounts for 3% of the 300 families in the adRP Cohort and 36% of Hispanic families in this cohort.

Solo dwarfs I: survey introduction and first results for the Sagittarius dwarf irregular galaxy

NASA Astrophysics Data System (ADS)

Higgs, C. R.; McConnachie, A. W.; Irwin, M.; Bate, N. F.; Lewis, G. F.; Walker, M. G.; Côté, P.; Venn, K.; Battaglia, G.

2016-05-01

We introduce the Solitary Local dwarfs survey (Solo), a wide-field photometric study targeting every isolated dwarf galaxy within 3 Mpc of the Milky Way. Solo is based on (u)gi multiband imaging from Canada-France-Hawaii Telescope/MegaCam for northern targets, and Magellan/Megacam for southern targets. All galaxies fainter than MV ≃ -18 situated beyond the nominal virial radius of the Milky Way and M31 (≳300 kpc) are included in this volume-limited sample, for a total of 42 targets. In addition to reviewing the survey goals and strategy, we present results for the Sagittarius dwarf irregular galaxy (Sag DIG), one of the most isolated, low-mass galaxies, located at the edge of the Local Group. We analyse its resolved stellar populations and their spatial distributions. We provide updated estimates of its central surface brightness and integrated luminosity, and trace its surface brightness profile to a level fainter than 30 mag arcsec-2. Sag DIG is well described by a highly elliptical (disc-like) system following a single component Sérsic model. However, a low-level distortion is present at the outer edges of the galaxy that, were Sag DIG not so isolated, would likely be attributed to some kind of previous tidal interaction. Further, we find evidence of an extremely low level, extended distribution of stars beyond ˜5 arcmin (>1.5 kpc) that suggests Sag DIG may be embedded in a very low-density stellar halo. We compare the stellar and H I structures of Sag DIG, and discuss results for this galaxy in relation to other isolated, dwarf irregular galaxies in the Local Group.

South Atlantic sag basins: new petroleum system components

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henry, S.G.; Mello, M.R.

Newly discovered pre-salt source rocks, reservoirs and seals need to be included as components to the petroleum systems of both sides of the South Atlantic. These new components lie between the pre-salt rift strata and the Aptian salt layers, forming large, post-rift, thermal subsidence sag basins. These are differentiated from the older rift basins by the lack of syn-rift faulting and a reflector geometry that is parallel to the base salt regional unconformity rather than to the Precambrian basement. These basins are observed in deep water regions overlying areas where both the mantle and the crust have been involved inmore » the extension. This mantle involvement creates post-rift subsiding depocenters in which deposition is continuous while proximal rift-phase troughs with little or no mantle involvement are bypassed and failed to accumulate potential source rocks during anoxic times. These features have been recognized in both West African Kwanza Basin and in the East Brasil Rift systems. The pre-salt source rocks that are in the West African sag basins were deposited in lacustrine brackish to saline water environment and are geochemically distinct from the older, syn-rift fresh to brackish water lakes, as well as from younger, post-salt marine anoxic environments of the drift phase. Geochemical analyses of the source rocks and their oils have shown a developing source rock system evolving from isolated deep rift lakes to shallow saline lakes, and culminating with the infill of the sag basin by large saline lakes to a marginally marine restricted gulf. Sag basin source rocks may be important in the South Atlantic petroleum system by charging deep-water prospects where syn-rift source rocks are overmature and the post-salt sequences are immature.« less

Deconvolution of Composition and Crystallite Size of Silver Hollandite Nanorods: Influence on Electrochemistry

DOE PAGES

Durham, Jessica L.; Huang, Jianping; Zhang, Bingjie; ...

2017-12-16

In this paper, silver hollandite (Ag 1.4Mn 8O 16) has been synthesized by an aqueous, low-temperature co-precipitation technique to afford silver hollandite with distinct crystallite sizes (10 and 15 nm, identified as S-Ag 1.4Mn 8O 16 and L-Ag 1.4Mn 8O 16, respectively) and equivalent silver content (x), allowing for the deconvolution of electrochemical effects related to crystallite size and silver content. The as-prepared silver hollandite materials were confirmed to be structurally analogous. Notably, TEM imaging reveals a high degree of bundling of S-Ag 1.4Mn 8O 16 nanorods compared to L-Ag 1.4Mn 8O 16 which facilitates more intimate connection of themore » S-Ag 1.4Mn 8O 16 material with enhanced interparticle contact. The electrochemical behavior and lithium diffusion properties were investigated by galvanostatic cycling, CV, electrochemical impedance, pulsed-discharge experiments, and ex-situ XAS analysis of cycled cathodes. Lithium based electrochemical cells containing S-Ag 1.4Mn 8O 16 delivered a capacity 15X higher than L-Ag 1.4Mn 8O 16 on cycle 1. Ex-situ XAS demonstrated structural change for S-Ag 1.4Mn 8O 16 and formation of Ag 0 on insertion of 3.8 Li + intercalation. However, the samples of L-Ag 1.4Mn 8O 16 were lithiated by a more limited 0.25 molar equivalents, where no significant structural changes were observed. Finally, the findings affirm crystallite size significantly impacts electrochemistry independent of cation occupancy of the α-MnO 2 type structure.« less

Adaptive sequential controller

DOEpatents

El-Sharkawi, Mohamed A.; Xing, Jian; Butler, Nicholas G.; Rodriguez, Alonso

1994-01-01

An adaptive sequential controller (50/50') for controlling a circuit breaker (52) or other switching device to substantially eliminate transients on a distribution line caused by closing and opening the circuit breaker. The device adaptively compensates for changes in the response time of the circuit breaker due to aging and environmental effects. A potential transformer (70) provides a reference signal corresponding to the zero crossing of the voltage waveform, and a phase shift comparator circuit (96) compares the reference signal to the time at which any transient was produced when the circuit breaker closed, producing a signal indicative of the adaptive adjustment that should be made. Similarly, in controlling the opening of the circuit breaker, a current transformer (88) provides a reference signal that is compared against the time at which any transient is detected when the circuit breaker last opened. An adaptive adjustment circuit (102) produces a compensation time that is appropriately modified to account for changes in the circuit breaker response, including the effect of ambient conditions and aging. When next opened or closed, the circuit breaker is activated at an appropriately compensated time, so that it closes when the voltage crosses zero and opens when the current crosses zero, minimizing any transients on the distribution line. Phase angle can be used to control the opening of the circuit breaker relative to the reference signal provided by the potential transformer.

Design of analog pixels front-end active feedback

NASA Astrophysics Data System (ADS)

Kmon, P.; Kadlubowski, L. A.; Kaczmarczyk, P.

2018-01-01

The paper presents the design of the active feedback used in a charge-sensitive amplifier. The predominant advantages of the presented circuit are its ability for setting wide range of pulse-time widths, small silicon area occupation and low power consumption. The feedback also allows sensor leakage current compensation and, thanks to an additional DC amplifier, it minimizes the output DC voltage variations, which is especially important in the DC coupled recording chain and for processes with limited supply voltage. The paper provides feedback description and its operation principle. The proposed circuit was designed in the CMOS 130nm technology.

Test Results From a Simulated High-Voltage Lunar Power Transmission Line

NASA Technical Reports Server (NTRS)

Birchenough, Arthur; Hervol, David

2008-01-01

The Alternator Test Unit (ATU) in the Lunar Power System Facility (LPSF) located at the NASA Glenn Research Center (GRC) in Cleveland, Ohio was modified to simulate high-voltage transmission capability. The testbed simulated a 1 km transmission cable length from the ATU to the LPSF using resistors and inductors installed between the distribution transformers. Power factor correction circuitry was used to compensate for the reactance of the distribution system to improve the overall power factor. This test demonstrated that a permanent magnet alternator can successfully provide high-frequency ac power to a lunar facility located at a distance.

Test Results from a Simulated High Voltage Lunar Power Transmission Line

NASA Technical Reports Server (NTRS)

Birchenough, Arthur; Hervol, David

2008-01-01

The Alternator Test Unit (ATU) in the Lunar Power System Facility (LPSF) located at the NASA Glenn Research Center (GRC) in Cleveland, OH was modified to simulate high voltage transmission capability. The testbed simulated a 1 km transmission cable length from the ATU to the LPSF using resistors and inductors installed between the distribution transformers. Power factor correction circuitry was used to compensate for the reactance of the distribution system to improve the overall power factor. This test demonstrated that a permanent magnet alternator can successfully provide high frequency AC power to a lunar facility located at a distance.

Design of Low Power CMOS Read-Out with TDI Function for Infrared Linear Photodiode Array Detectors

NASA Technical Reports Server (NTRS)

Vizcaino, Paul; Ramirez-Angulo, Jaime; Patel, Umesh D.

2007-01-01

A new low voltage CMOS infrared readout circuit using the buffer-direct injection method is presented. It uses a single supply voltage of 1.8 volts and a bias current of 1uA. The time-delay integration technique is used to increase the signal to noise ratio. A current memory circuit with faulty diode detection is used to remove dark current for background compensation and to disable a photodiode in a cell if detected as faulty. Simulations are shown that verify the circuit that is currently in fabrication in 0.5ym CMOS technology.

Static inverter with synchronous output waveform synthesized by time-optimal-response feedback

NASA Technical Reports Server (NTRS)

Kernick, A.; Stechschulte, D. L.; Shireman, D. W.

1976-01-01

Time-optimal-response 'bang-bang' or 'bang-hang' technique, using four feedback control loops, synthesizes static-inverter sinusoidal output waveform by self-oscillatory but yet synchronous pulse-frequency-modulation (SPFM). A single modular power stage per phase of ac output entails the minimum of circuit complexity while providing by feedback synthesis individual phase voltage regulation, phase position control and inherent compensation simultaneously for line and load disturbances. Clipped sinewave performance is described under off-limit load or input voltage conditions. Also, approaches to high power levels, 3-phase arraying and parallel modular connection are given.

Limited genetic diversity among Sarcocystis neurona strains infecting southern sea otters precludes distinction between marine and terrestrial isolates

PubMed Central

Wendte, J.M.; Miller, M.A.; Nandra, A.K.; Peat, S.M.; Crosbie, P.R.; Conrad, P.A.; Grigg, M.E.

2010-01-01

Sarcocystis neurona is an apicomplexan parasite identified as a cause of fatal neurological disease in the threatened southern sea otter (Enhydra lutris nereis). In an effort to characterize virulent S. neurona strains circulating in the marine ecosystem, this study developed a range of markers relevant for molecular genotyping. Highly conserved sequences within the 18S ribosomal gene array, the plastid-encoded RNA polymerase (RPOb) and the cytochrome c oxidase subunit 1 mitochondrial gene (CO1) were assessed for their ability to distinguish isolates at the genus and species level. For within-species comparisons, five surface antigens (SnSAG1-SnSAG5) and one high resolution microsatellite marker (Sn9) were developed as genotyping markers to evaluate intra-strain diversity. Molecular analysis at multiple loci revealed insufficient genetic diversity to distinguish terrestrial isolates from strains infecting marine mammals. Furthermore, SnSAG specific primers applied against DNA from the closely related species, Sarcocystis falcatula, lead to the discovery of highly similar orthologs to SnSAG2, 3, and 4, calling into question the specificity of diagnostic tests based on these antigens. The results of this study suggest a population genetic structure for S. neurona similar to that reported for the related parasite, Toxoplasma gondii, dominated by a limited number of successful genotypes. PMID:20071081

Biological Mechanisms Underlying the Ultraviolet Radiation-Induced Formation of Skin Wrinkling and Sagging I: Reduced Skin Elasticity, Highly Associated with Enhanced Dermal Elastase Activity, Triggers Wrinkling and Sagging

PubMed Central

Imokawa, Genji; Ishida, Koichi

2015-01-01

The repetitive exposure of skin to ultraviolet B (UVB) preferentially elicits wrinkling while ultraviolet A (UVA) predominantly elicits sagging. In chronically UVB or UVA-exposed rat skin there is a similar tortuous deformation of elastic fibers together with decreased skin elasticity, whose magnitudes are greater in UVB-exposed skin than in UVA-exposed skin. Comparison of skin elasticity with the activity of matrix metalloproteinases (MMPs) in the dermis of ovariectomized rats after UVB or UVA irradiation demonstrates that skin elasticity is more significantly decreased in ovariectomized rats than in sham-operated rats, which is accompanied by a reciprocal increase in elastase activity but not in the activities of collagenases I or IV. Clinical studies using animal skin and human facial skin demonstrated that topical treatment with a specific inhibitor or an inhibitory extract of skin fibroblast-derived elastase distinctly attenuates UVB and sunlight-induced formation of wrinkling. Our results strongly indicated that the upregulated activity of skin fibroblast-derived elastase plays a pivotal role in wrinkling and/or sagging of the skin via the impairment of elastic fiber configuration and the subsequent loss of skin elasticity. PMID:25856675

Seismic identification and origin of shallow gas in the Baiyun Sag Northern South China Sea

NASA Astrophysics Data System (ADS)

Qin, Q.

2016-12-01

The analytics of three dimensional high resolution seismic data and multi-beam data gotten from Baiyun Sag(BYS), the northern South China Sea(SCS) reveals varieties of shallow gas indicators. Such indicators include gas chimneys, enhanced reflections, bright spots, pipes and acoustic blanking. Among them, the enhanced reflections suggest that the free gas has been presented. And, there are also some very high amplitude reflections and they have occurred in both deep and shallow sedimentary sections. Gas chimneys are dominant and pipes (line zones of big faults) also have been observed in much of the surveyed area if observing at 31 lines. Gas chimneys and pipes in the study area can be associated with some known faults that would act as migration pathways from deep fluids. There are some columnar zones of acoustic blanking in the survey area. This suggests that the observed structures in Baiyun sag sediments allow the emission of gases which might be for a large share of source rocks or deep gas reservoir, and there are abundant shallow gas in the Baiyun Sag. As we all know, the obvious characteristics of shallow gas are high pressure and highly dangerous. So our results are very essential to explore resources (hydrocarbon and gas hydrate) in such a petroliferous basin.

A high open-circuit voltage gallium nitride betavoltaic microbattery

NASA Astrophysics Data System (ADS)

Cheng, Zaijun; Chen, Xuyuan; San, Haisheng; Feng, Zhihong; Liu, Bo

2012-07-01

A high open-circuit voltage betavoltaic microbattery based on a gallium nitride (GaN) p-i-n homojunction is demonstrated. As a beta-absorbing layer, the low electron concentration of the n-type GaN layer is achieved by the process of Fe compensation doping. Under the irradiation of a planar solid 63Ni source with activity of 0.5 mCi, the open-circuit voltage of the fabricated microbattery with 2 × 2 mm2 area reaches as much as 1.64 V, which is the record value reported for betavoltaic batteries with 63Ni source, the short-circuit current was measured as 568 pA and the conversion effective of 0.98% was obtained. The experimental results suggest that GaN is a high-potential candidate for developing the betavoltaic microbattery.

Low speed phaselock speed control system. [for brushless dc motor

NASA Technical Reports Server (NTRS)

Fulcher, R. W.; Sudey, J. (Inventor)

1975-01-01

A motor speed control system for an electronically commutated brushless dc motor is provided which includes a phaselock loop with bidirectional torque control for locking the frequency output of a high density encoder, responsive to actual speed conditions, to a reference frequency signal, corresponding to the desired speed. The system includes a phase comparator, which produces an output in accordance with the difference in phase between the reference and encoder frequency signals, and an integrator-digital-to-analog converter unit, which converts the comparator output into an analog error signal voltage. Compensation circuitry, including a biasing means, is provided to convert the analog error signal voltage to a bidirectional error signal voltage which is utilized by an absolute value amplifier, rotational decoder, power amplifier-commutators, and an arrangement of commutation circuitry.

Retention behavior of neutral solutes in pressurized flow-driven capillary electrochromatography using an ODS column.

PubMed

Nakagawa, Hiroyuki; Kitagawa, Shinya; Araki, Shuki; Ohtani, Hajime

2006-02-01

Several alkyl benzenes are separated by pressurized flow-driven capillary electrochromatography using a temperature-controlled capillary column packed with octadecyl siloxane-modified silica gel, and the effect of applied voltage on the retention is investigated. The van't Hoff plot shows good linearity at the column temperature between 305 and 330 K under applications from -6 to +6 kV. The applied voltage causes a relatively large variation in the enthalpy and the entropy of transfer of the solute from the mobile phase to the stationary phase (> 20%). However, the direction of variation in the enthalpy is almost opposite to that in the entropy, both of which might compensate each other. Therefore, the retention factor is not significantly varied (< 4%) by the application of voltage.

Comparison of in-situ delay monitors for use in Adaptive Voltage Scaling

NASA Astrophysics Data System (ADS)

Pour Aryan, N.; Heiß, L.; Schmitt-Landsiedel, D.; Georgakos, G.; Wirnshofer, M.

2012-09-01

In Adaptive Voltage Scaling (AVS) the supply voltage of digital circuits is tuned according to the circuit's actual operating condition, which enables dynamic compensation to PVTA variations. By exploiting the excessive safety margins added in state-of-the-art worst-case designs considerable power saving is achieved. In our approach, the operating condition of the circuit is monitored by in-situ delay monitors. This paper presents different designs to implement the in-situ delay monitors capable of detecting late but still non-erroneous transitions, called Pre-Errors. The developed Pre-Error monitors are integrated in a 16 bit multiplier test circuit and the resulting Pre-Error AVS system is modeled by a Markov chain in order to determine the power saving potential of each Pre-Error detection approach.

An integrated modeling method for wind turbines

NASA Astrophysics Data System (ADS)

Fadaeinedjad, Roohollah

To study the interaction of the electrical, mechanical, and aerodynamic aspects of a wind turbine, a detailed model that considers all these aspects must be used. A drawback of many studies in the area of wind turbine simulation is that either a very simple mechanical model is used with a detailed electrical model, or vice versa. Hence the interactions between electrical and mechanical aspects of wind turbine operation are not accurately taken into account. In this research, it will be shown that a combination of different simulation packages, namely TurbSim, FAST, and Simulink can be used to model the aerodynamic, mechanical, and electrical aspects of a wind turbine in detail. In this thesis, after a review of some wind turbine concepts and software tools, a simulation structure is proposed for studying wind turbines that integrates the mechanical and electrical components of a wind energy conversion device. Based on the simulation structure, a comprehensive model for a three-bladed variable speed wind turbine with doubly-fed induction generator is developed. Using the model, the impact of a voltage sag on the wind turbine tower vibration is investigated under various operating conditions such as power system short circuit level, mechanical parameters, and wind turbine operating conditions. It is shown how an electrical disturbance can cause more sustainable tower vibrations under high speed and turbulent wind conditions, which may disrupt the operation of pitch control system. A similar simulation structure is used to model a two-bladed fixed speed wind turbine with an induction generator. An extension of the concept is introduced by adding a diesel generator system. The model is utilized to study the impact of the aeroelastic aspects of wind turbine (i.e. tower shadow, wind shears, yaw error, turbulence, and mechanical vibrations) on the power quality of a stand-alone wind-diesel system. Furthermore, an IEEE standard flickermeter model is implemented in a Simulink environment to study the flicker contribution of the wind turbine in the wind-diesel system. By using a new wind power plant representation method, a large wind farm (consisting of 96 fixed speed wind turbines) is modelled to study the power quality of wind power system. The flicker contribution of wind farm is also studied with different wind turbine numbers, using the flickermeter model. Keywords. Simulink, FAST, TurbSim, AreoDyn, wind energy, doubly-fed induction generator, variable speed wind turbine, voltage sag, tower vibration, power quality, flicker, fixed speed wind turbine, wind shear, tower shadow, and yaw error.

Multifunctional voltage source inverter for renewable energy integration and power quality conditioning.

PubMed

Dai, NingYi; Lam, Chi-Seng; Zhang, WenChen

2014-01-01

In order to utilize the energy from the renewable energy sources, power conversion system is necessary, in which the voltage source inverter (VSI) is usually the last stage for injecting power to the grid. It is an economical solution to add the function of power quality conditioning to the grid-connected VSI in the low-voltage distribution system. Two multifunctional VSIs are studied in this paper, that is, inductive-coupling VSI and capacitive-coupling VSI, which are named after the fundamental frequency impedance of their coupling branch. The operation voltages of the two VSIs are compared when they are used for renewable energy integration and power quality conditioning simultaneously. The operation voltage of the capacitive-coupling VSI can be set much lower than that of the inductive-coupling VSI when reactive power is for compensating inductive loads. Since a large portion of the loads in the distribution system are inductive, the capacitive-coupling VSI is further studied. The design and control method of the multifunctional capacitive-coupling VSI are proposed in this paper. Simulation and experimental results are provided to show its validity.

A novel control strategy for enhancing the LVRT and voltage support capabilities of DFIG

NASA Astrophysics Data System (ADS)

Shen, Yangwu; Zhang, Bin; Liang, Liqing; Cui, Ting

2018-02-01

A novel integrated control strategy is proposed in this paper to enhance the low voltage ride through capacity for the double-fed induction generator by equipping an energy storage system. The energy storage system is installed into the DC-link capacitor of the DFIG and used to control the DC-link voltage during normal or transient operations. The energy storage device will absorb or compensate the power difference between the captured wind power and the power injected to the grid during the normal and transient period, and the grid side converter can be free from maintaining the voltage stability of the DC-link capacitor. Thus, the grid-side converter is changed to reactive power support while the rotor-side converter is used to control the maximum power production during normal operation. The grid-side converter and rotor-side converter will act as reactive power sources to further enhance the voltage support capability of double-fed induction generator during the transient period. Numerical Simulation are performed to validate the effectiveness of the proposed control designs.

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.

Multifunctional Voltage Source Inverter for Renewable Energy Integration and Power Quality Conditioning

PubMed Central

Dai, NingYi; Lam, Chi-Seng; Zhang, WenChen

2014-01-01

In order to utilize the energy from the renewable energy sources, power conversion system is necessary, in which the voltage source inverter (VSI) is usually the last stage for injecting power to the grid. It is an economical solution to add the function of power quality conditioning to the grid-connected VSI in the low-voltage distribution system. Two multifunctional VSIs are studied in this paper, that is, inductive-coupling VSI and capacitive-coupling VSI, which are named after the fundamental frequency impedance of their coupling branch. The operation voltages of the two VSIs are compared when they are used for renewable energy integration and power quality conditioning simultaneously. The operation voltage of the capacitive-coupling VSI can be set much lower than that of the inductive-coupling VSI when reactive power is for compensating inductive loads. Since a large portion of the loads in the distribution system are inductive, the capacitive-coupling VSI is further studied. The design and control method of the multifunctional capacitive-coupling VSI are proposed in this paper. Simulation and experimental results are provided to show its validity. PMID:25177725

Systems and methods for compensating for electrical converter nonlinearities

DOEpatents

Perisic, Milun; Ransom, Ray M.; Kajouke, Lateef A.

2013-06-18

Systems and methods are provided for delivering energy from an input interface to an output interface. An electrical system includes an input interface, an output interface, an energy conversion module coupled between the input interface and the output interface, and a control module. The control module determines a duty cycle control value for operating the energy conversion module to produce a desired voltage at the output interface. The control module determines an input power error at the input interface and adjusts the duty cycle control value in a manner that is influenced by the input power error, resulting in a compensated duty cycle control value. The control module operates switching elements of the energy conversion module to deliver energy to the output interface with a duty cycle that is influenced by the compensated duty cycle control value.

Cable delay compensator for microwave signal distribution over optical fibers

NASA Astrophysics Data System (ADS)

Primas, Lori E.

1990-12-01

The basic principles of microwave fiber-optic systems are outlined with emphasis on fiber-optic cable delay compensators (CDC). Degradation of frequency and phase stability is considered, and it is pointed out that the long-term stability of a fiber-optic link is degraded by group delay variations due to temperature fluctuations in the optical fiber and low-frequency noise characteristics of the laser. A CDC employing a voltage-controlled oscillator to correct for phase variations in the optical fiber is presented, and the static as well as dynamic closed-loop analyses of the fiber-optic CDC are discussed. A constructed narrow-band fiber-optic CDC is shown to reduce phase variations caused by temperature fluctuations by a factor of 400. A wide-band CDC utilizing a temperature-controlled coil of fiber to compensate for phase delay is also proposed.

A novel input-parasitic compensation technique for a nanopore-based CMOS DNA detection sensor

NASA Astrophysics Data System (ADS)

Kim, Jungsuk

2016-12-01

This paper presents a novel input-parasitic compensation (IPC) technique for a nanopore-based complementary metal-oxide-semiconductor (CMOS) DNA detection sensor. A resistive-feedback transimpedance amplifier is typically adopted as the headstage of a DNA detection sensor to amplify the minute ionic currents generated from a nanopore and convert them to a readable voltage range for digitization. But, parasitic capacitances arising from the headstage input and the nanopore often cause headstage saturation during nanopore sensing, thereby resulting in significant DNA data loss. To compensate for the unwanted saturation, in this work, we propose an area-efficient and automated IPC technique, customized for a low-noise DNA detection sensor, fabricated using a 0.35- μm CMOS process; we demonstrated this prototype in a benchtop test using an α-hemolysin ( α-HL) protein nanopore.

Compensation of the sheath effects in cylindrical floating probes

NASA Astrophysics Data System (ADS)

Park, Ji-Hwan; Chung, Chin-Wook

2018-05-01

In cylindrical floating probe measurements, the plasma density and electron temperature are overestimated due to sheath expansion and oscillation. To reduce these sheath effects, a compensation method based on well-developed floating sheath theories is proposed and applied to the floating harmonic method. The iterative calculation of the Allen-Boyd-Reynolds equation can derive the floating sheath thickness, which can be used to calculate the effective ion collection area; in this way, an accurate ion density is obtained. The Child-Langmuir law is used to calculate the ion harmonic currents caused by sheath oscillation of the alternating-voltage-biased probe tip. Accurate plasma parameters can be obtained by subtracting these ion harmonic currents from the total measured harmonic currents. Herein, the measurement principles and compensation method are discussed in detail and an experimental demonstration is presented.

Characterization of an E3 Ubiquitin Ligase that Degrades Neurofibromin in Vitro and Vivo

DTIC Science & Technology

2012-04-01

andDuronio, R.J. (2008). Identifying determinants of cullin binding specificity among the three functionally different Drosophila melanogaster Roc...Deshaies and Joazeiro, 2009; Nakayama and Nakayama, 2006). Although a large number of F-box proteins were found in the human genome (Jin et al., 2004... genome walking (Figure S1A). The insertion disrupts theDevelopmentaSag transcript resulting in a truncated fusionmRNA that encodes partial Sag N

76 FR 34855 - Safety Zones; Marine Events in Captain of the Port Long Island Sound Zone

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-15

... in approximate position 40[deg]39'06.45'' N, 073[deg]8'45.26'' W (NAD 83). 7 July 7.1 Sag Harbor... Beach, Sag Harbor, NY in approximate position 41[deg]00'26'' N, 072[deg]17'9'' W (NAD 83). 7.2 Mason's...]57'48.22'' W (NAD 83). 7.3 Lawrence Beach Club Fireworks...... Date: July 2, 2011. Time: 8:30 p.m. to...

Seroconversion in captive African wild dogs (Lycaon pictus) following administration of a chicken head bait/SAG-2 oral rabies vaccine combination.

PubMed

Knobel, D L; Liebenberg, A; Du Toit, J T

2003-03-01

This study determined the proportion of captive juvenile and adult African wild dogs (Lycaon pictus) that developed protective titres of rabies neutralising antibodies following ingestion of a chicken head bait/SAG-2 oral rabies vaccine combination. A single chicken head containing 1.8 ml of SAG-2 vaccine (10(8.0) TCID50/ml) in a plastic blister was fed to each of eight adult and three juvenile wild dogs. Bait ingestion resulted in a significant rise in serum neutralising antibody titres. Overall seroconversion rate was eight out of 11 (72.7%), and all the puppies and five out of eight (62.5%) adults showed potentially protective levels of antibodies on day 31. The mean post-vaccination neutralising antibody titre was within the range reported to be protective against challenge with virulent rabies virus in other species.

Vocalization characteristics of North Atlantic right whale surface active groups in the calving habitat, southeastern United States.

PubMed

Trygonis, Vasilis; Gerstein, Edmund; Moir, Jim; McCulloch, Stephen

2013-12-01

Passive acoustic surveys were conducted to assess the vocal behavior of North Atlantic right whales (Eubalaena glacialis) in the designated critical calving habitat along the shallow coastal waters of southeastern United States. Underwater vocalizations were recorded using autonomous buoys deployed in close proximity to surface active groups (SAGs). Nine main vocalization types were identified with manual inspection of spectrograms, and standard acoustic descriptors were extracted. Classification trees were used to examine the distinguishing characteristics of calls and quantify their variability within the SAG vocal repertoire. The results show that descriptors of frequency, bandwidth, and spectral disorder are the most important parameters for partitioning the SAG repertoire, contrary to duration-related measures. The reported source levels and vocalization statistics provide sound production data vital to inform regional passive acoustic monitoring and conservation for this endangered species.

The structural and functional role of myelin fast-migrating cerebrosides: pathological importance in multiple sclerosis

PubMed Central

Podbielska, Maria; Levery, Steven B; Hogan, Edward L

2011-01-01

A family of neutral glycosphingolipids containing a 3-O-acetyl-sphingosine galactosylceramide (3-SAG) has been characterized. Seven new derivatives of galactosylceramide (GalCer), designated as fast-migrating cerebrosides (FMCs) by TLC retention factor, have been identified. The simplest compounds – FMC-1 and FMC-2 – of this series have been characterized as the 3-SAG containing nonhydroxy and hydroxy fatty acyl, respectively. The next two – FMC-3 and FMC-4 – add 6-O-acetyl-galactose and the most complex glycosphingolipids, FMC-5, -6 and -7, are 2,3,4,6-tetra-O-acetyl-3-SAG. These hydrophobic myelin lipid biomarkers coappear with GalCer during myelinogenesis and disappear along with GalCer in de- or dys-myelinating disorders. Myelin lipid antigens, including FMCs, are keys to myelin biology, opening the possibility of new and novel immune modulatory tools for treatment of autoimmune diseases including multiple sclerosis. PMID:22701512

Comparison of oil removal in surfactant alternating gas with water alternating gas, water flooding and gas flooding in secondary oil recovery process.

PubMed

Salehi, Mehdi Mohammad; Safarzadeh, Mohammad Amin; Sahraei, Eghbal; Nejad, Seyyed Alireza Tabatabaei

2014-08-01

Growing oil prices coupled with large amounts of residual oil after operating common enhanced oil recovery methods has made using methods with higher operational cost economically feasible. Nitrogen is one of the gases used in both miscible and immiscible gas injection process in oil reservoir. In heterogeneous formations gas tends to breakthrough early in production wells due to overriding, fingering and channeling. Surfactant alternating gas (SAG) injection is one of the methods commonly used to decrease this problem. Foam which is formed on the contact of nitrogen and surfactant increases viscosity of injected gas. This increases the oil-gas contact and sweep efficiency, although adsorption of surfactant on rock surface can causes difficulties and increases costs of process. Many parameters must be considered in design of SAG process. One of the most important parameters is SAG ratio that should be in optimum value to improve the flooding efficiency. In this study, initially the concentration of surfactant was optimized due to minimization of adsorption on rock surface which results in lower cost of surfactant. So, different sodium dodecyl sulfate (SDS) concentrations of 100, 500, 1000, 2000, 3000 and 4000 ppm were used to obtain the optimum concentration at 70 °C and 144.74×10 5  Pa. A simple, clean and relatively fast spectrophotometric method was used for determination of surfactant which is based on the formation of an ion-pair. Then the effect of surfactant to gas volume ratio on oil recovery in secondary oil recovery process during execution of immiscible surfactant alternating gas injection was examined experimentally. The experiments were performed with sand pack under certain temperature, pressure and constant rate. Experiments were performed with surfactant to gas ratio of 1:1, 1:2, 1:3, 2:1 and 3:1 and 1.2 pore volume injected. Then, comparisons were made between obtained results (SAG) with water flooding, gas flooding and water alternating gas (WAG) processes. This study shows that using the concentration of 1500 ppm of surfactant solution is practical and economical. Results also show that the SAG ratio of 1:1 with 0.2 cm 3 /min at temperature and pressure of 70 °C and 144.74×10 5  Pa, has the maximum oil removal efficiency. In this SAG ratio, stable foam was formed and viscous fingering delayed in comparison to other ratios. Finally, the results demonstrated that SAG injection has higher oil recovery in comparison to other displacement methods (water flooding, gas flooding and WAG).

Temperature compensation analysis of liquid lens for variable-focus control

NASA Astrophysics Data System (ADS)

Chen, Shu-Jung; Tai, Tsai-Lin; Shen, Chih-Hsiung

2006-01-01

In this work, a fabrication and temperature compensation analysis and electrowetting for the liquid lenses is proposed. The unique capability of controlling the lens profile during the electrowetting fabrication processes is successfully demonstrated for different ambient temperature environment. For a lens fabricated on a hydrophobic Teflon layer, it is found that when the applied voltage is increased, the focal length increases, and the curvature decreases. One challenge for the liquid lens is operating temperature range. Due to the environment temperature change, the ability of controlling the lens profile is analyzed and measured. The description of change in contact angle corresponding to the variation of ambient temperature is derived. Based on this description, we firstly derive the control of voltage vs. temperature for a fixed dioptric power. The control of lens during a focusing action was studied by observation of the image formed by the light through the transparent bottom of ITO glass. Under several conditions of ambient temperature change, capability of controlling the lens profile for a fixed focus is successfully demonstrated by experiments.

Ion accelerator systems for high power 30 cm thruster operation

NASA Technical Reports Server (NTRS)

Aston, G.

1982-01-01

Two and three-grid accelerator systems for high power ion thruster operation were investigated. Two-grid translation tests show that over compensation of the 30 cm thruster SHAG grid set spacing the 30 cm thruster radial plasma density variation and by incorporating grid compensation only sufficient to maintain grid hole axial alignment, it is shown that beam current gains as large as 50% can be realized. Three-grid translation tests performed with a simulated 30 cm thruster discharge chamber show that substantial beamlet steering can be reliably affected by decelerator grid translation only, at net-to-total voltage ratios as low as 0.05.

A parallel input composite transimpedance amplifier.

PubMed

Kim, D J; Kim, C

2018-01-01

A new approach to high performance current to voltage preamplifier design is presented. The design using multiple operational amplifiers (op-amps) has a parasitic capacitance compensation network and a composite amplifier topology for fast, precision, and low noise performance. The input stage consisting of a parallel linked JFET op-amps and a high-speed bipolar junction transistor (BJT) gain stage driving the output in the composite amplifier topology, cooperating with the capacitance compensation feedback network, ensures wide bandwidth stability in the presence of input capacitance above 40 nF. The design is ideal for any two-probe measurement, including high impedance transport and scanning tunneling microscopy measurements.

A parallel input composite transimpedance amplifier

NASA Astrophysics Data System (ADS)

Kim, D. J.; Kim, C.

2018-01-01

A new approach to high performance current to voltage preamplifier design is presented. The design using multiple operational amplifiers (op-amps) has a parasitic capacitance compensation network and a composite amplifier topology for fast, precision, and low noise performance. The input stage consisting of a parallel linked JFET op-amps and a high-speed bipolar junction transistor (BJT) gain stage driving the output in the composite amplifier topology, cooperating with the capacitance compensation feedback network, ensures wide bandwidth stability in the presence of input capacitance above 40 nF. The design is ideal for any two-probe measurement, including high impedance transport and scanning tunneling microscopy measurements.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Xiaohu; Shi, Di; Wang, Zhiwei

Shunt FACTS devices, such as, a Static Var Compensator (SVC), are capable of providing local reactive power compensation. They are widely used in the network to reduce the real power loss and improve the voltage profile. This paper proposes a planning model based on mixed integer conic programming (MICP) to optimally allocate SVCs in the transmission network considering load uncertainty. The load uncertainties are represented by a number of scenarios. Reformulation and linearization techniques are utilized to transform the original non-convex model into a convex second order cone programming (SOCP) model. Numerical case studies based on the IEEE 30-bus systemmore » demonstrate the effectiveness of the proposed planning model.« less

Increase in the Random Dopant Induced Threshold Fluctuations and Lowering in Sub 100 nm MOSFETs Due to Quantum Effects: A 3-D Density-Gradient Simulation Study

NASA Technical Reports Server (NTRS)

Asenov, Asen; Slavcheva, G.; Brown, A. R.; Davies, J. H.; Saini, S.

2000-01-01

In this paper we present a detailed simulation study of the influence of quantum mechanical effects in the inversion layer on random dopant induced threshold voltage fluctuations and lowering in sub 100 nm MOSFETs. The simulations have been performed using a 3-D implementation of the density gradient (DG) formalism incorporated in our established 3-D atomistic simulation approach. This results in a self-consistent 3-D quantum mechanical picture, which implies not only the vertical inversion layer quantisation but also the lateral confinement effects related to current filamentation in the 'valleys' of the random potential fluctuations. We have shown that the net result of including quantum mechanical effects, while considering statistical dopant fluctuations, is an increase in both threshold voltage fluctuations and lowering. At the same time, the random dopant induced threshold voltage lowering partially compensates for the quantum mechanical threshold voltage shift in aggressively scaled MOSFETs with ultrathin gate oxides.

Keys to the Larval and Adult Mosquitoes of Espiritu Santo (New Hebrides) with Notes on Their Bionomics

DTIC Science & Technology

1946-01-01

coconut halves and husks , bamboo stumps, and artificial containers such as tin cans, sagging tent covers, tarpaulins, and wooden frames holding...The larvae are occasionally found with hebrideus breeding in water held in wooden frames or coconut husks , but they are also found in tree holes...HEBRIDEUS EDW. Larvae: This is a common larva found in tree holes, coconut husks and shells, sagging tents and tarpulins, wooden frames, rain

Limited genetic diversity among Sarcocystis neurona strains infecting southern sea otters precludes distinction between marine and terrestrial isolates.

PubMed

Wendte, J M; Miller, M A; Nandra, A K; Peat, S M; Crosbie, P R; Conrad, P A; Grigg, M E

2010-04-19

Sarcocystis neurona is an apicomplexan parasite identified as a cause of fatal neurological disease in the threatened southern sea otter (Enhydra lutris nereis). In an effort to characterize virulent S. neurona strains circulating in the marine ecosystem, this study developed a range of markers relevant for molecular genotyping. Highly conserved sequences within the 18S ribosomal gene array, the plastid-encoded RNA polymerase (RPOb) and the cytochrome c oxidase subunit 1 mitochondrial gene (CO1) were assessed for their ability to distinguish isolates at the genus and species level. For within-species comparisons, five surface antigens (SnSAG1-SnSAG5) and one high resolution microsatellite marker (Sn9) were developed as genotyping markers to evaluate intra-strain diversity. Molecular analysis at multiple loci revealed insufficient genetic diversity to distinguish terrestrial isolates from strains infecting marine mammals. Furthermore, SnSAG specific primers applied against DNA from the closely related species, Sarcocystis falcatula, lead to the discovery of highly similar orthologs to SnSAG2, 3, and 4, calling into question the specificity of diagnostic tests based on these antigens. The results of this study suggest a population genetic structure for S. neurona similar to that reported for the related parasite, Toxoplasma gondii, dominated by a limited number of successful genotypes. Published by Elsevier B.V.

Molecular detection and genetic characterization of Toxoplasma gondii infection in sika deer (Cervus nippon) in China.

PubMed

Cong, Wei; Qin, Si-Yuan; Meng, Qing-Feng; Zou, Feng-Cai; Qian, Ai-Dong; Zhu, Xing-Quan

2016-04-01

The objective of the present study was to investigate the prevalence and genetic characterization of Toxoplasma gondii infection in sika deer in China. During August 2014 to November 2014, a total of 450 tissue samples coming from 150 sika deer were collected to detect the T. gondii B1 gene using a nested PCR, and the positive samples were genotyped at 11 genetic markers (SAG1, 5'- and 3'-SAG2, alternative SAG2, SAG3, BTUB, GRA6, L358, PK1, c22-8, c29-2, and Apico) using multilocus polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technology. Seventeen of 150 sika deer (11.33%) were tested positive by nested PCR. Six DNA samples from the 17 positive samples were completely typed, in which 4 samples from lung tissues, and 2 from muscular tissues, were identified as ToxoDB Genotype #9 (http://toxodb.org/toxo/). The results of the present study revealed the existence of T. gondii infection in sika deer in China, which provided the information of T. gondii genetic diversity in this host species. This study also indicated that ToxoDB Genotype #9 has a wide distribution in sika deer that could be potential reservoirs for T. gondii transmission, which may pose a threat to human health. Copyright © 2016 Elsevier B.V. All rights reserved.

Thermal-history reconstruction of the Baiyun Sag in the deep-water area of the Pearl River Mouth Basin, northern South China Sea

NASA Astrophysics Data System (ADS)

Tang, Xiaoyin; Yang, Shuchun; Hu, Shengbiao

2017-11-01

The Baiyun Sag, located in the deep-water area of the northern South China Sea, is the largest and deepest subbasin in the Pearl River Mouth Basin and one of the most important hydrocarbon-accumulation depression areas in China. Thermal history is widely thought to be of great importance in oil and gas potential assessment of a basin as it controls the timing of hydrocarbon generation and expulsion from the source rock. In order to unravel the paleo-heat flow of the Baiyun Sag, we first analyzed tectonic subsidence of 55 pseudo-wells constructed based on newly interpreted seismic profiles, along with three drilled wells. We then carried out thermal modeling using the multi-stage finite stretching method and calibrated the results using collected present-day vitrinite reflectance data and temperature data. Results indicate that the first and second heating of the Baiyun Sag after 49 Ma ceased at 33.9 Ma and 23 Ma. Reconstructed average basal paleoheat flow values at the end of the rifting periods are 57.7-86.2 mW/m2 and 66.7-97.3 mW/m2, respectively. Following the last heating period at 23 Ma, the study area has undergone a persistent thermal attenuation phase, and basal heat flow has cooled down to 64.0-79.2 mW/m2 at present.

Genetic characterization of Toxoplasma gondii from Brazilian wildlife revealed abundant new genotypes.

PubMed

Vitaliano, S N; Soares, H S; Minervino, A H H; Santos, A L Q; Werther, K; Marvulo, M F V; Siqueira, D B; Pena, H F J; Soares, R M; Su, C; Gennari, S M

2014-12-01

This study aimed to isolate and genotype T. gondii from Brazilian wildlife. For this purpose, 226 samples were submitted to mice bioassay and screened by PCR based on 18S rRNA sequences. A total of 15 T. gondii isolates were obtained, including samples from four armadillos (three Dasypus novemcinctus, one Euphractus sexcinctus), three collared anteaters (Tamandua tetradactyla), three whited-lipped peccaries (Tayassu pecari), one spotted paca (Cuniculus paca), one oncilla (Leopardus tigrinus), one hoary fox (Pseudalopex vetulus), one lineated woodpecker (Dryocopus lineatus) and one maned wolf (Chrysocyon brachyurus). DNA from the isolates, originated from mice bioassay, and from the tissues of the wild animal, designated as "primary samples", were genotyped by PCR-restriction fragment length polymorphism (PCR/RFLP), using 12 genetic markers (SAG1, SAG2, alt.SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L258, PK1, CS3 and Apico). A total of 17 genotypes were identified, with 13 identified for the first time and four already reported in published literature. Results herein obtained corroborate previous studies in Brazil, confirming high diversity and revealing unique genotypes in this region. Given most of genotypes here identified are different from previous studies in domestic animals, future studies on T. gondii from wildlife is of interest to understand population genetics and structure of this parasite.

Genetic characterization of Toxoplasma gondii from Brazilian wildlife revealed abundant new genotypes

PubMed Central

Vitaliano, S.N.; Soares, H.S.; Minervino, A.H.H.; Santos, A.L.Q.; Werther, K.; Marvulo, M.F.V.; Siqueira, D.B.; Pena, H.F.J.; Soares, R.M.; Su, C.; Gennari, S.M.

2014-01-01

This study aimed to isolate and genotype T. gondii from Brazilian wildlife. For this purpose, 226 samples were submitted to mice bioassay and screened by PCR based on 18S rRNA sequences. A total of 15 T. gondii isolates were obtained, including samples from four armadillos (three Dasypus novemcinctus, one Euphractus sexcinctus), three collared anteaters (Tamandua tetradactyla), three whited-lipped peccaries (Tayassu pecari), one spotted paca (Cuniculus paca), one oncilla (Leopardus tigrinus), one hoary fox (Pseudalopex vetulus), one lineated woodpecker (Dryocopus lineatus) and one maned wolf (Chrysocyon brachyurus). DNA from the isolates, originated from mice bioassay, and from the tissues of the wild animal, designated as “primary samples”, were genotyped by PCR–restriction fragment length polymorphism (PCR/RFLP), using 12 genetic markers (SAG1, SAG2, alt.SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L258, PK1, CS3 and Apico). A total of 17 genotypes were identified, with 13 identified for the first time and four already reported in published literature. Results herein obtained corroborate previous studies in Brazil, confirming high diversity and revealing unique genotypes in this region. Given most of genotypes here identified are different from previous studies in domestic animals, future studies on T. gondii from wildlife is of interest to understand population genetics and structure of this parasite. PMID:25426424

Delayed expression of SAGs correlates with longevity in CMS wheat plants compared to its fertile plants.

PubMed

Semwal, Vimal Kumar; Singh, Bhupinder; Khanna-Chopra, Renu

2014-04-01

Reproductive sinks regulate monocarpic senescence in crop plants. Monocarpic senescence was studied in wheat fertile (cv. HW 2041) and its isonuclear cytoplasmic male sterile (CMS) line. CMS plants exhibited slower rate of senescence accompanied by longer green leaf area duration and slower deceleration in chlorophyll, protein content, PN and rubisco content coupled with lower protease activities than fertile (F) plants. CMS plants also exhibited lower ROS levels and less membrane damage than F plants. CMS plants maintained better antioxidant defense, less oxidative damage in chloroplast and higher transcript levels of both rbcL and rbcS genes during senescence than F plants. F plants exhibited early induction and higher expression of SAGs like serine and cysteine proteases, glutamine synthetases GS1 and GS2, WRKY53 transcription factor and decline in transcript levels of CAT1 and CAT2 genes than CMS plants. Hence, using genetically fertile and its CMS line of wheat it is confirmed that delayed senescence in the absence of reproductive sinks is linked with slower protein oxidation, rubisco degradation and delayed activation of SAGs. Better antioxidant defense in chloroplasts at later stages of senescence was able to mitigate the deleterious effects of ROS in CMS plants. We propose that delayed increase in ROS in cytoplasmic male sterile wheat plants resulted in delayed activation of WRKY53, SAGs and the associated biochemical changes than fertile plants.

Thermomagnetic properties of peat-soil layers from Sag pond near Lembang Fault, West Java, Indonesia

NASA Astrophysics Data System (ADS)

Iryanti, Mimin; Wibowo, Dimas Maulana; Bijaksana, Satria

2015-09-01

Sag pond is a body of water near fault system as water flows blocked by the fault. Sag pond is a special type of environment for peat formation as peat layers in were deposited as the fault moves in episodic fashion. Depending on the history of the fault, peat layers are often interrupted by soil layers. In this study, core of peat-soil layers from a Sag pond in Karyawangi Village near Lembang Fault was obtained and analyzed for its magnetic properties. The 5 m core was obtained using a hand auger. Individual samples were obtained every cm and measured for their magnetic susceptibility. In general, there are three distinct magnetic susceptibility layers that were associated with peat and soil layers. The upper first 1 m is unconsolidated mud layer with its relatively high magnetic susceptibility. Between 1-2.81 m, there is consolidated mud layer and the lowest part (2.82-5) m is basically peat layer. Six samples were then measured for their thermomagnetic properties by measuring their susceptibility during heating and cooling from room temperature to 700°C. The thermomagnetic profiles provide Curie temperatures for various magnetic minerals in the cores. It was found that the upper part (unconsolidated mud) contains predominantly iron-oxides, such as magnetite while the lowest part (peat layer) contains significant amount of iron-sulphides, presumably greigite.

Adaptive super-twisting sliding mode control for a three-phase single-stage grid-connected differential boost inverter based photovoltaic system.

PubMed

Pati, Akshaya K; Sahoo, N C

2017-07-01

This paper presents an adaptive super-twisting sliding mode control (STC) along with double-loop control for voltage tracking performance of three-phase differential boost inverter and DC-link capacitor voltage regulation in grid-connected PV system. The effectiveness of the proposed control strategies are demonstrated under realistic scenarios such as variations in solar insolation, load power demand, grid voltage, and transition from grid-connected to standalone mode etc. Additional supplementary power quality control functions such as harmonic compensation, and reactive power management are also investigated with the proposed control strategy. The results are compared with conventional proportional-integral controller, and PWM sliding mode controller. The system performance is evaluated in simulation and in real-time. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Highly tunable local gate controlled complementary graphene device performing as inverter and voltage controlled resistor.

PubMed

Kim, Wonjae; Riikonen, Juha; Li, Changfeng; Chen, Ya; Lipsanen, Harri

2013-10-04

Using single-layer CVD graphene, a complementary field effect transistor (FET) device is fabricated on the top of separated back-gates. The local back-gate control of the transistors, which operate with low bias at room temperature, enables highly tunable device characteristics due to separate control over electrostatic doping of the channels. Local back-gating allows control of the doping level independently of the supply voltage, which enables device operation with very low VDD. Controllable characteristics also allow the compensation of variation in the unintentional doping typically observed in CVD graphene. Moreover, both p-n and n-p configurations of FETs can be achieved by electrostatic doping using the local back-gate. Therefore, the device operation can also be switched from inverter to voltage controlled resistor, opening new possibilities in using graphene in logic circuitry.

SU-E-T-268: Proton Radiosurgery End-To-End Testing Using Lucy 3D QA Phantom

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, D; Gordon, I; Ghebremedhin, A

2014-06-01

Purpose: To check the overall accuracy of proton radiosurgery treatment delivery using ready-made circular collimator inserts and fixed thickness compensating boluses. Methods: Lucy 3D QA phantom (Standard Imaging Inc. WI, USA) inserted with GaFchromicTM film was irradiated with laterally scattered and longitudinally spread-out 126.8 MeV proton beams. The tests followed every step in the proton radiosurgery treatment delivery process: CT scan (GE Lightspeed VCT), target contouring, treatment planning (Odyssey 5.0, Optivus, CA), portal calibration, target localization using robotic couch with image guidance and dose delivery at planned gantry angles. A 2 cm diameter collimator insert in a 4 cm diametermore » radiosurgery cone and a 1.2 cm thick compensating flat bolus were used for all beams. Film dosimetry (RIT114 v5.0, Radiological Imaging Technology, CO, USA) was used to evaluate the accuracy of target localization and relative dose distributions compared to those calculated by the treatment planning system. Results: The localization accuracy was estimated by analyzing the GaFchromic films irradiated at gantry 0, 90 and 270 degrees. We observed 0.5 mm shift in lateral direction (patient left), ±0.9 mm shift in AP direction and ±1.0 mm shift in vertical direction (gantry dependent). The isodose overlays showed good agreement (<2mm, 50% isodose lines) between measured and calculated doses. Conclusion: Localization accuracy depends on gantry sag, CT resolution and distortion, DRRs from treatment planning computer, localization accuracy of image guidance system, fabrication of ready-made aperture and cone housing. The total deviation from the isocenter was 1.4 mm. Dose distribution uncertainty comes from distal end error due to bolus and CT density, in addition to localization error. The planned dose distribution was well matched (>90%) to the measured values 2%/2mm criteria. Our test showed the robustness of our proton radiosurgery treatment delivery system using ready-made collimator inserts and fixed thickness compensating boluses.« less

Liquid crystal modulator with ultra-wide dynamic range and adjustable driving voltage.

PubMed

Wang, Xing-jun; Huang, Zhang-di; Feng, Jing; Chen, Xiang-fei; Liang, Xiao; Lu, Yan-qing

2008-08-18

We demonstrated a reflective-type liquid crystal (LC) intensity modulator in 1550 nm telecomm band. An effective way to compensate the residual phase of a LC cell is proposed. With the adjustment of a true zero-order quarter wave plate and enhanced by total internal reflection induced birefringence, over 53 dB dynamic range was achieved, which is much desired for some high-end optical communication, infrared scene projection applications. In addition, the driving voltages were decreased and adjustable. Mechanical and spectral tolerance measurements show that our LC modulator is quite stable. Further applications of our experimental setup were discussed including bio-sensors and high speed modulators.

Equivalent model and power flow model for electric railway traction network

NASA Astrophysics Data System (ADS)

Wang, Feng

2018-05-01

An equivalent model of the Cable Traction Network (CTN) considering the distributed capacitance effect of the cable system is proposed. The model can be divided into 110kV side and 27.5kV side two kinds. The 110kV side equivalent model can be used to calculate the power supply capacity of the CTN. The 27.5kV side equivalent model can be used to solve the voltage of the catenary. Based on the equivalent simplified model of CTN, the power flow model of CTN which involves the reactive power compensation coefficient and the interaction of voltage and current, is derived.

THERMAL CONDUCTIVITY ANALYSIS OF GASES

DOEpatents

Clark, W.J.

1949-06-01

This patent describes apparatus for the quantitative analysis of a gaseous mixture at subatmospheric pressure by measurement of its thermal conductivity. A heated wire forms one leg of a bridge circuit, while the gas under test is passed about the wire at a constant rate. The bridge unbalance will be a measure of the change in composition of the gas, if compensation is made for the effect due to gas pressure change. The apparatus provides a voltage varying with fluctuations of pressure in series with the indicating device placed across the bridge, to counterbalance the voltage change caused by fluctuations in the pressure of the gaseous mixture.

Improved Control of Charging Voltage for Li-Ion Battery

NASA Technical Reports Server (NTRS)

Timmerman, Paul; Bugga, Ratnakumar

2006-01-01

The protocol for charging a lithium-ion battery would be modified, according to a proposal, to compensate for the internal voltage drop (charging current internal resistance of the battery). The essence of the modification is to provide for measurement of the internal voltage drop and to increase the terminal-voltage setting by the amount of the internal voltage drop. Ordinarily, a lithium-ion battery is charged at constant current until its terminal voltage attains a set value equal to the nominal full-charge potential. The set value is chosen carefully so as not to exceed the lithium-plating potential, because plated lithium in metallic form constitutes a hazard. When the battery is charged at low temperature, the internal voltage drop is considerable because the electrical conductivity of the battery electrolyte is low at low temperature. Charging the battery at high current at any temperature also gives rise to a high internal voltage drop. In some cases, the internal voltage drop can be as high as 1 volt per cell. Because the voltage available for charging is less than the terminal voltage by the amount of the internal voltage drop, the battery is not fully charged (see figure), even when the terminal voltage reaches the set value. In the modified protocol, the charging current would be periodically interrupted so that the zero-current battery-terminal voltage indicative of the state of charge could be measured. The terminal voltage would also be measured at full charging current. The difference between the full-current and zero-current voltages would equal the internal voltage drop. The set value of terminal voltage would then be increased beyond the nominal full-charge potential by the amount of the internal voltage drop. This adjustment would be performed repeatedly, in real time, so that the voltage setting would track variations in the internal voltage drop to afford full charge without risk of lithium plating. If the charging current and voltage settings were controlled by a computer, then this method of charge control could readily be implemented in software.

Comparative study of protective activities of Neospora caninum bradyzoite antigens, NcBAG1, NcBSR4, NcMAG1, and NcSAG4, in a mouse model of acute parasitic infection.

PubMed

Uchida, Masaki; Nagashima, Kotomi; Akatsuka, Yui; Murakami, Takashi; Ito, Akira; Imai, Soichi; Ike, Kazunori

2013-02-01

Neospora caninum is an obligate intracellular protozoan parasite that causes severe neuromuscular diseases, repeated abortion, stillbirth, and congenital infection in livestock and companion animals. The development of an effective vaccine against neosporosis in cattle is an important issue due to the significant worldwide economic impact of this disease. We evaluated the immunogenicity of four bradyzoite antigens, NcBAG1 (first described in this study), NcBSR4, NcMAG1, and NcSAG4, using an acute infection mouse model to determine synergistic effects with the tachyzoite antigen as a candidate for vaccine production. Mice were inoculated with the recombinant vaccines (r-)NcBAG1, rNcBSR4, rNcMAG1, rNcSAG4, or phosphate-buffered saline (PBS) (adjuvant control group) in an oil-in-water emulsion with bitter gourd extract, a Th1 immune stimulator, or PBS alone as the infection control group. Mice inoculated with each vaccine developed antigen-specific IgG1 and IgG2a antibodies and isolated splenocytes from mice produced high levels of interferon-γ when infected with the N. caninum tachyzoite. The mice inoculated with rNcBAG1, rNcMAG1, or rNcSAG4 developed slight to moderate clinical symptoms but did not succumb to infection. In contrast, rNcBSR4 and both control groups developed severe disease and some mice required euthanasia. The parasitic burden in the brain tissues of vaccinated mice was assessed by N. caninum-specific real-time PCR at 5 weeks after infection. The parasite load in rNcBAG1-, rNcMAG1-, and rNcSAG4-inoculated mice was significantly lower than that in adjuvant and infection control mice. Therefore, these antigens may be useful for the production of a N. caninum-specific vaccination protocol.

Toxoplasma gondii: prevalence and characterization of new genotypes in free-range chickens from south Brazil.

PubMed

Vieira, Fernando Emmanuel Gonçalves; Sasse, João Pedro; Minutti, Ana Flávia; Miura, Ana Carolina; de Barros, Luiz Daniel; Cardim, Sergio Tosi; Martins, Thais Agostinho; de Seixas, Mércia; Yamamura, Milton Issashi; Su, Chunlei; Garcia, João Luis

2018-03-01

Toxoplasma gondii is an intracellular parasite that can infect all warm-blooded animals including humans. Recent studies showed that T. gondii strains from South America are genetically diverse. The present work aimed to determine T. gondii prevalence in free-ranging chicken in northwest Parana state in Brazil by two serological tests, to isolate the parasites from seropositive chickens and to genotype the isolates. Antibodies to T. gondii in 386 serum samples from 24 farms were investigated by immunofluorescence antibody assay (IFA) and modified agglutination test (MAT). Samples having titers ≥ 16 were considered positive for both tests. Among the 386 serum samples, 102 (26.4%) were positive for IFA, 64 (16.6%) were positive for MAT, 47 (12.2%) were positive in both tests, and 119 (30.8%) were positive in at least one of the two tests. Brain and pool of heart, lung, and liver from the 119 seropositive chickens were used for mouse bioassay to isolate the parasites. Thirty eight (31.9%) of these seropositive chickens were considered positives in mouse bioassay and 18 isolates were obtained. The isolates were characterized by 10 PCR-RFLP genetic markers including SAG1, SAG2 (5'-3'SAG2, alt.SAG2), SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico. Results of genotyping were compared with the genotypes in ToxoDB database. It revealed ten genotypes, including ToxoDB PCR-RFLP genotypes #6 (n = 2), #19 (n = 1), #21 (n = 2), #111 (n = 2), #152 (n = 1), and #175 (n = 1) and four new types not described before. Our results confirmed a high genetic diversity of this parasite in southern Brazil and also showed that the use of two serological tests in combination can improve the chance of T. gondii isolation. More studies should be taken to determine the zoonotic potential of chickens in the transmission of T. gondii.

Prevalence, risk factors and genetic characterization of Toxoplasma gondii in sick pigs and stray cats in Jiangsu Province, eastern China.

PubMed

Hou, Zhao-Feng; Su, Shi-Jie; Liu, Dan-Dan; Wang, Le-le; Jia, Chuan-Li; Zhao, Zhen-Xing; Ma, Yi-Fei; Li, Qiao-Qiao; Xu, Jin-Jun; Tao, Jian-Ping

2018-06-01

Toxoplasma gondii is an obligate intracellular parasitic protozoan with a worldwide distribution. The parasites in edible tissues of pigs and oocysts from cats are the major sources of T. gondii infection in humans. However, there are no data from sick pigs in veterinary clinics or from stray cats in Jiangsu Province, eastern China. In total, biological samples from 141 sick pigs and 64 stray cats were collected from this region. The rate of T. gondii infection in sick pigs was 46.81% using a polymerase chain reaction (PCR), and the overall prevalence of toxoplasmosis in stray cats was 34.38% by PCR and an enzyme-linked immunosorbent assay (ELISA). T. gondii was significantly more prevalent in lungs and heart than in liver and spleen (P < 0.05). Age and geographic region were considered to be the main risk factors associated with T. gondii infection in these pigs. The DNA samples from 17 sick pigs and seven stray cats, were successfully genotyped by multilocus PCR-restriction fragment length polymorphism (PCR-RFLP) with 10 genetic markers [SAG1, SAG2 (5'-3'SAG2, alt. SAG2), SAG3, GRA6, PK1, c22-8, c29-2, BTUB, L358 and Apico]. Six distinct genotypes were found, which were designated ToxoDB PCR-RFLP genotypes #9 (Chinese I), #10 (Type I), #213, and #89, and New 1 and New 2. Chinese I is the most prevalent T. gondii genotype in this region. The two new genotypes (designated New 1 and New 2) are reported and the ToxoDB PCR-RFLP genotype #89 is found for the first time in China. Such information will be useful for the prevention, diagnosis and treatment of porcine toxoplasmosis in Jiangsu Province, eastern China. Copyright © 2018 Elsevier B.V. All rights reserved.

Monolithic amplifier with stable, high resistance feedback element and method for fabricating the same

DOEpatents

O'Connor, Paul

1998-08-11

A monolithic amplifier includes a stable, high resistance feedback circuit and a dynamic bias circuit. The dynamic bias circuit is formed with active elements matched to those in the amplifier and feedback circuit to compensate for variations in the operating and threshold voltages thereby maintaining a stable resistance in the feedback circuit.

Numerical investigation of the double-arcing phenomenon in a cutting arc torch

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mancinelli, B. R., E-mail: bmancinelli@frvt.utn.edu.ar; Minotti, F. O.; Kelly, H.

2014-07-14

A numerical investigation of the double-arcing phenomenon in a cutting arc torch is reported. The dynamics of the double-arcing were simulated by using a two-dimensional model of the gas breakdown development in the space-charge layer contiguous to the nozzle of a cutting arc torch operated with oxygen. The kinetic scheme includes ionization of heavy particles by electron impact, electron attachment, electron detachment, electron–ion recombination, and ion–ion recombination. Complementary measurements during double-arcing phenomena were also conducted. A marked rise of the nozzle voltage was found. The numerical results showed that the dynamics of a cathode spot at the exit of themore » nozzle inner surface play a key role in the raising of the nozzle voltage, which in turn allows more electrons to return to the wall at the nozzle inlet. The return flow of electrons thus closes the current loop of the double-arcing. The increase in the (floating) nozzle voltage is due to the fact that the increased electron emission at the spot is mainly compensated by the displacement current (the ions do not play a relevant role due to its low-mobility) until that the stationary state is achieved and the electron return flow fully-compensates the electron emission at the spot. A fairly good agreement was found between the model and the experiment for a spot emission current growth rate of the order of 7 × 10{sup 4} A/s.« less

A robust hybrid fuzzy-simulated annealing-intelligent water drops approach for tuning a distribution static compensator nonlinear controller in a distribution system

NASA Astrophysics Data System (ADS)

Bagheri Tolabi, Hajar; Hosseini, Rahil; Shakarami, Mahmoud Reza

2016-06-01

This article presents a novel hybrid optimization approach for a nonlinear controller of a distribution static compensator (DSTATCOM). The DSTATCOM is connected to a distribution system with the distributed generation units. The nonlinear control is based on partial feedback linearization. Two proportional-integral-derivative (PID) controllers regulate the voltage and track the output in this control system. In the conventional scheme, the trial-and-error method is used to determine the PID controller coefficients. This article uses a combination of a fuzzy system, simulated annealing (SA) and intelligent water drops (IWD) algorithms to optimize the parameters of the controllers. The obtained results reveal that the response of the optimized controlled system is effectively improved by finding a high-quality solution. The results confirm that using the tuning method based on the fuzzy-SA-IWD can significantly decrease the settling and rising times, the maximum overshoot and the steady-state error of the voltage step response of the DSTATCOM. The proposed hybrid tuning method for the partial feedback linearizing (PFL) controller achieved better regulation of the direct current voltage for the capacitor within the DSTATCOM. Furthermore, in the event of a fault the proposed controller tuned by the fuzzy-SA-IWD method showed better performance than the conventional controller or the PFL controller without optimization by the fuzzy-SA-IWD method with regard to both fault duration and clearing times.

Green synthesis of silver nanoparticles using leaf extract of medicinally potent plant Saraca indica: a novel study

NASA Astrophysics Data System (ADS)

Perugu, Shyam; Nagati, Veerababu; Bhanoori, Manjula

2016-06-01

Eco-friendly silver nanoparticles (AgNPs) have various applications in modern biotechnology for better outcomes and benefits to the society. In the present study, we report an eco-friendly synthesis of silver nanoparticles using Saraca indica leaf extract. Characterization of S. indica silver nanoparticles (SAgNPs) was carried out by Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectrometry, Zeta potential, and transmission electron microscopy. SAgNPs showed antimicrobial activity against Gram-negative and Gram-positive bacteria.

The voltage dependence of NADPH oxidase reveals why phagocytes need proton channels

NASA Astrophysics Data System (ADS)

DeCoursey, Thomas E.; Morgan, Deri; Cherny, Vladimir V.

2003-04-01

The enzyme NADPH oxidase in phagocytes is important in the body's defence against microbes: it produces superoxide anions (O2-, precursors to bactericidal reactive oxygen species). Electrons move from intracellular NADPH, across a chain comprising FAD (flavin adenine dinucleotide) and two haems, to reduce extracellular O2 to O2-. NADPH oxidase is electrogenic, generating electron current (Ie) that is measurable under voltage-clamp conditions. Here we report the complete current-voltage relationship of NADPH oxidase, the first such measurement of a plasma membrane electron transporter. We find that Ie is voltage-independent from -100mV to >0mV, but is steeply inhibited by further depolarization, and is abolished at about +190mV. It was proposed that H+ efflux mediated by voltage-gated proton channels compensates Ie, because Zn2+ and Cd2+ inhibit both H+ currents and O2- production. Here we show that COS-7 cells transfected with four NADPH oxidase components, but lacking H+ channels, produce O2- in the presence of Zn2+ concentrations that inhibit O2- production in neutrophils and eosinophils. Zn2+ does not inhibit NADPH oxidase directly, but through effects on H+ channels. H+ channels optimize NADPH oxidase function by preventing membrane depolarization to inhibitory voltages.

Clues to understanding cold sensation: Thermodynamics and electrophysiological analysis of the cold receptor TRPM8

PubMed Central

Brauchi, Sebastian; Orio, Patricio; Latorre, Ramon

2004-01-01

The cold and menthol receptor, TRPM8, also designated CMR1, is a member of the transient receptor potential (TRP) family of excitatory ion channels. TRPM8 is a channel activated by cold temperatures, voltage, and menthol. In this study, we characterize the cold- and voltage-induced activation of TRPM8 channel in an attempt to identify the temperature- and voltage-dependent components involved in channel activation. Under equilibrium conditions, decreasing temperature has two effects. (i) It shifts the normalized conductance vs. voltage curves toward the left, along the voltage axis. This effect indicates that the degree of order is higher when the channel is in the open configuration. (ii) It increases the maximum channel open probability, suggesting that temperature affects both voltage-dependent and -independent pathways. In the temperature range between 18°C and 25°C, large changes in enthalpy (ΔH = -112 kcal/mol) and entropy (ΔS = -384 cal/mol K) accompany the activation process. The Q10 calculated in the same temperature range is 24. This thermodynamic analysis strongly suggests that the process of opening involves large conformational changes of the channel-forming protein. Therefore, the highly temperature-dependent transition between open and closed configurations is possible because enthalpy and entropy are both large and compensate each other. Our data also demonstrate that temperature and voltage interact allosterically to enhance channel opening. PMID:15492228

Optimization of power systems with voltage security constraints

NASA Astrophysics Data System (ADS)

Rosehart, William Daniel

As open access market principles are applied to power systems, significant changes in their operation and control are occurring. In the new marketplace, power systems are operating under higher loading conditions as market influences demand greater attention to operating cost versus stability margins. Since stability continues to be a basic requirement in the operation of any power system, new tools are being considered to analyze the effect of stability on the operating cost of the system, so that system stability can be incorporated into the costs of operating the system. In this thesis, new optimal power flow (OPF) formulations are proposed based on multi-objective methodologies to optimize active and reactive power dispatch while maximizing voltage security in power systems. The effects of minimizing operating costs, minimizing reactive power generation and/or maximizing voltage stability margins are analyzed. Results obtained using the proposed Voltage Stability Constrained OPF formulations are compared and analyzed to suggest possible ways of costing voltage security in power systems. When considering voltage stability margins the importance of system modeling becomes critical, since it has been demonstrated, based on bifurcation analysis, that modeling can have a significant effect of the behavior of power systems, especially at high loading levels. Therefore, this thesis also examines the effects of detailed generator models and several exponential load models. Furthermore, because of its influence on voltage stability, a Static Var Compensator model is also incorporated into the optimization problems.

Improved Transient and Steady-State Performances of Series Resonant ZCS High-Frequency Inverter-Coupled Voltage Multiplier Converter with Dual Mode PFM Control Scheme

NASA Astrophysics Data System (ADS)

Chu, Enhui; Gamage, Laknath; Ishitobi, Manabu; Hiraki, Eiji; Nakaoka, Mutsuo

The A variety of switched-mode high voltage DC power supplies using voltage-fed type or current-fed type high-frequency transformer resonant inverters using MOS gate bipolar power transistors; IGBTs have been recently developed so far for a medical-use X-ray high power generator. In general, the high voltage high power X-ray generator using voltage-fed high frequency inverter with a high voltage transformer link has to meet some performances such as (i) short rising period in start transient of X-ray tube voltage (ii) no overshoot transient response in tube voltage, (iii) minimized voltage ripple in periodic steady-state under extremely wide load variations and filament heater current fluctuation conditions of the X-ray tube. This paper presents two lossless inductor snubber-assisted series resonant zero current soft switching high-frequency inverter using a diode-capacitor ladder type voltage multiplier called Cockcroft-Walton circuit, which is effectively implemented for a high DC voltage X-ray power generator. This DC high voltage generator which incorporates pulse frequency modulated series resonant inverter using IGBT power module packages is based on the operation principle of zero current soft switching commutation scheme under discontinuous resonant current and continuous resonant current transition modes. This series capacitor compensated for transformer resonant power converter with a high frequency transformer linked voltage boost multiplier can efficiently work a novel selectively-changed dual mode PFM control scheme in order to improve the start transient and steady-state response characteristics and can completely achieve stable zero current soft switching commutation tube filament current dependent for wide load parameter setting values with the aid of two lossless inductor snubbers. It is proved on the basis of simulation and experimental results in which a simple and low cost control implementation based on selectively-changed dual-mode PFM for high-voltage X-ray DC-DC power converter with a voltage multiplier strategy has some specified voltage pattern tracking voltage response performances under rapid rising time and no overshoot in start transient tube voltage as well as the minimized steady-state voltage ripple in tube voltage.

Improved method to fully compensate the spatial phase nonuniformity of LCoS devices with a Fizeau interferometer.

PubMed

Lu, Qiang; Sheng, Lei; Zeng, Fei; Gao, Shijie; Qiao, Yanfeng

2016-10-01

Liquid crystal on silicon (LCoS) devices usually show spatial phase nonuniformity (SPNU) in applications of phase modulation, which comprises the phase retardance nonuniformity (PRNU) as a function of the applied voltage and inherent wavefront distortion (WFD) introduced by the device itself. We propose a multipoint calibration method utilizing a Fizeau interferometer to compensate SPNU of the device. Calibration of PRNU is realized by defining a grid of 3×6 cells onto the aperture and then calculating phase retardance of each cell versus a gradient gray pattern. With designing an adjusted gray pattern calculated by the calibrated multipoint phase retardance function, compensation of inherent WFD is achieved. The peak-to-valley (PV) value of the residual WFD compensated by the multipoint calibration method is significantly reduced from 2.5λ to 0.140λ, while the PV value of the residual WFD after global calibration is reduced to 0.364λ. Experimental results of the generated finite-energy 2D Airy beams in Fourier space demonstrate the effectiveness of this multipoint calibration method.

Compensator design for corrector magnet power supply of TPS facility

NASA Astrophysics Data System (ADS)

Wong, Y.-S.; Chen, J.-F.; Liu, K.-B.; Liu, C.-Y.; Wang, B.-S.

2017-10-01

From 2012 to 2015, Taiwan government has a most important technology project is Taiwan Photon Source (TPS), the total budget of TPS fund to over US300 million. It set up a synchrotron storage ring (electron energy of 3.3 GeV, circumference of 518 m, and low emittance) that provides one of the world's brightest synchrotron sources of x-rays. This study presents a compensator design for corrector magnet power supply to avoid limitations in stabilizing the frequency when the machine output current load is valid. A lead-lag compensator had been built in a full-bridge converter to improve the system bandwidth. Lead-lag compensators influence various disciplines, such as robotics, satellite control, automobile diagnostics, and laser frequency stabilization. These components are important building blocks in analog control systems and can also be used in digital control. A 50V output voltage and 10A output current prototype converter is fabricated in the laboratory. From the experimental results, the effectiveness of the control loop design can be verified from the gain margin and phase margin.

A temperature compensation methodology for piezoelectric based sensor devices

NASA Astrophysics Data System (ADS)

Wang, Dong F.; Lou, Xueqiao; Bao, Aijian; Yang, Xu; Zhao, Ji

2017-08-01

A temperature compensation methodology comprising a negative temperature coefficient thermistor with the temperature characteristics of a piezoelectric material is proposed to improve the measurement accuracy of piezoelectric sensing based devices. The piezoelectric disk is characterized by using a disk-shaped structure and is also used to verify the effectiveness of the proposed compensation method. The measured output voltage shows a nearly linear relationship with respect to the applied pressure by introducing the proposed temperature compensation method in a temperature range of 25-65 °C. As a result, the maximum measurement accuracy is observed to be improved by 40%, and the higher the temperature, the more effective the method. The effective temperature range of the proposed method is theoretically analyzed by introducing the constant coefficient of the thermistor (B), the resistance of initial temperature (R0), and the paralleled resistance (Rx). The proposed methodology can not only eliminate the influence of piezoelectric temperature dependent characteristics on the sensing accuracy but also decrease the power consumption of piezoelectric sensing based devices by the simplified sensing structure.

Macrophage migration inhibitory factor acts as a neurotrophin in the developing inner ear.

PubMed

Bank, Lisa M; Bianchi, Lynne M; Ebisu, Fumi; Lerman-Sinkoff, Dov; Smiley, Elizabeth C; Shen, Yu-chi; Ramamurthy, Poornapriya; Thompson, Deborah L; Roth, Therese M; Beck, Christine R; Flynn, Matthew; Teller, Ryan S; Feng, Luming; Llewellyn, G Nicholas; Holmes, Brandon; Sharples, Cyrrene; Coutinho-Budd, Jaeda; Linn, Stephanie A; Chervenak, Andrew P; Dolan, David F; Benson, Jennifer; Kanicki, Ariane; Martin, Catherine A; Altschuler, Richard; Koch, Alisa E; Koch, Alicia E; Jewett, Ethan M; Germiller, John A; Barald, Kate F

2012-12-01

This study is the first to demonstrate that macrophage migration inhibitory factor (MIF), an immune system 'inflammatory' cytokine that is released by the developing otocyst, plays a role in regulating early innervation of the mouse and chick inner ear. We demonstrate that MIF is a major bioactive component of the previously uncharacterized otocyst-derived factor, which directs initial neurite outgrowth from the statoacoustic ganglion (SAG) to the developing inner ear. Recombinant MIF acts as a neurotrophin in promoting both SAG directional neurite outgrowth and neuronal survival and is expressed in both the developing and mature inner ear of chick and mouse. A MIF receptor, CD74, is found on both embryonic SAG neurons and adult mouse spiral ganglion neurons. Mif knockout mice are hearing impaired and demonstrate altered innervation to the organ of Corti, as well as fewer sensory hair cells. Furthermore, mouse embryonic stem cells become neuron-like when exposed to picomolar levels of MIF, suggesting the general importance of this cytokine in neural development.

Pattern Transitions in a Soft Cylindrical Shell

NASA Astrophysics Data System (ADS)

Yang, Yifan; Dai, Hui-Hui; Xu, Fan; Potier-Ferry, Michel

2018-05-01

Instability patterns of rolling up a sleeve appear more intricate than the ones of walking over a rug on floor, both characterized as systems of uniaxially compressed soft film on stiff substrate. This can be explained by curvature effects. To investigate pattern transitions on a curved surface, we study a soft shell sliding on a rigid cylinder by experiments, computations and theoretical analyses. We reveal a novel postbuckling phenomenon involving multiple successive bifurcations: smooth-wrinkle-ridge-sagging transitions. The shell initially buckles into periodic axisymmetric wrinkles at the threshold and then a wrinkle-to-ridge transition occurs upon further axial compression. When the load increases to the third bifurcation, the amplitude of the ridge reaches its limit and the symmetry is broken with the ridge sagging into a recumbent fold. It is identified that hysteresis loops and the Maxwell equal-energy conditions are associated with the coexistence of wrinkle-ridge or ridge-sagging patterns. Such a bifurcation scenario is inherently general and independent of material constitutive models.

Improving Energy Efficiency Via Optimized Charge Motion and Slurry Flow in Plant Scale Sag Mills

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raj K. Rajamani

2006-07-21

A research team from the University of Utah is working to make inroads into saving energy in these SAG mills. In 2003, Industries of the Future Program of the Department of Energy tasked the University of Utah team to build a partnership between the University and the mining industry for the specific purpose of reducing energy consumption in SAG mills. A partnership was formed with Cortez Gold Mines, Outokumpu Technology, Kennecott Utah Copper Corporation, and Process Engineering Resources Inc. At Cortez Gold Operations the shell and pulp lifters of the semiautogenous grinding mill was redesigned. The redesigned shell lifter hasmore » been in operation for over three years and the redesigned pulp lifter has been in operation for over nine months now. This report summarizes the dramatic reductions in energy consumption. Even though the energy reductions are very large, it is safe to say that a 20% minimum reduction would be achieved in any future installations of this technology.« less

The irradiation influence on the properties of silver sulfide (Ag2S) colloidal nanoparticles

NASA Astrophysics Data System (ADS)

Rempel, S. V.; Kuznetsova, Yu. V.; Gerasimov, E. Yu.; Rempel', A. A.

2017-08-01

The aqueous solutions of different stability containing silver sulfide (Ag2S) nanoparticles are studied. The stable, transparent, and turbid solutions have been subjected to daylight for 7 months, to ultraviolet and laser irradiation, as well as to an electron beam. Solar radiation is found to favor the Ag2S reduction to Ag and/or the formation of Ag2S/Ag hybrid nanoparticles in the solution. At a high amount of hybrid nanoparticles, the exciton-plasmon interaction causes asymmetry in the absorption spectra. The exposure of Ag2S particles precipitated from the solution with the electron beam leads to the reversible growth of Ag threads. The possible exciton-plasmon interplay mechanisms in Ag2S/Ag hybrid nanoparticles are considered. The physical mechanisms of the changing Ag2S stoichiometry, the formation of metallic Ag and Ag2S/Ag hybrid nanoparticles are the generation of hot carriers and the energy transfer (exciton-plasmon interaction) in a metal-semiconductor hybrid nanosystem are elucidated, as well.

Characterization of the disassembly and reassembly of the HBV glycoprotein surface antigen, a pliable nanoparticle vaccine platform

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gallagher, John R.; Torian, Udana; McCraw, Dustin

While nanoparticle vaccine technology is gaining interest due to the success of vaccines like those for the human papillomavirus that is based on viral capsid nanoparticles, little information is available on the disassembly and reassembly of viral surface glycoprotein-based nanoparticles. One such particle is the hepatitis B virus surface antigen (sAg) that exists as nanoparticles. Here we show, using biochemical analysis coupled with electron microscopy, that sAg nanoparticle disassembly requires both reducing agent to disrupt intermolecular disulfide bonds, and detergent to disrupt hydrophobic interactions that stabilize the nanoparticle. Particles were otherwise resistant to salt and urea, suggesting the driving mechanismmore » of particle formation involves hydrophobic interactions. We reassembled isolated sAg protein into nanoparticles by detergent removal and reassembly resulted in a wider distribution of particle diameters. Knowledge of these driving forces of nanoparticle assembly and stability should facilitate construction of epitope-displaying nanoparticles that can be used as immunogens in vaccines.« less

Visualization of an air-water interface on superhydrophobic surfaces in turbulent channel flows

NASA Astrophysics Data System (ADS)

Kim, Hyunseok; Park, Hyungmin

2017-11-01

In the present study, three-dimensional deformation of air-water interface on superhydrophobic surfaces in turbulent channel flows at the Reynolds numbers of Re = 3000 and 10000 is measured with RICM (Reflection Interference Contrast Microscopy) technique. Two different types of roughness feature of circular hole and rectangular grate are considered, whose depth is 20 μm and diameter (or width) is varied between 20-200 μm. Since the air-water interface is always at de-pinned state at the considered condition, air-water interface shape and its sagging velocity is maintained to be almost constant as time goes one. In comparison with the previous results under the laminar flow, due to turbulent characteristics of the flow, sagging velocity is much faster. Based on the measured sagging profiles, a modified model to describe the air-water interface dynamics under turbulent flows is suggested. Supported by City of Seoul through Seoul Urban Data Science Laboratory Project (Grant No 0660-20170004) administered by SNU Big Data Institute.

Atypical Toxoplasma gondii genotype in feral cats from the Fernando de Noronha Island, northeastern Brazil.

PubMed

Melo, R P B; Almeida, J C; Lima, D C V; Pedrosa, C M; Magalhães, F J R; Alcântara, A M; Barros, L D; Vieira, R F C; Garcia, J L; Mota, R A

2016-07-15

Toxoplasma gondii isolates from Brazil have a different phenotypic and genotypic pattern, with predominance of virulent isolates and recombinant genotypes, compared to the North Hemisphere. Considering that a new T. gondii genotype, non-pathogenic to mice, was previously identified from free-range chickens from the Fernando de Noronha Island, Brazil, this study aimed to identify genotypes of this parasite in tissue samples of feral cats (Felis catus) from this Brazilian Island. Anti-T. gondii IgG antibodies were detected in 18/31 (58%) feral cats. Two non-virulent T. gondii isolates were obtained by mouse bioassay. Genotyping was performed by PCR-RFLP using 10 genetic markers (SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, PK1, L358 and Apico) and an atypical strain of T. gondii (ToxoDB #146) was identified. This is the first report of this genotype in feral cats. Copyright © 2016 Elsevier B.V. All rights reserved.

3D Power Line Extraction from Multiple Aerial Images.

PubMed

Oh, Jaehong; Lee, Changno

2017-09-29

Power lines are cables that carry electrical power from a power plant to an electrical substation. They must be connected between the tower structures in such a way that ensures minimum tension and sufficient clearance from the ground. Power lines can stretch and sag with the changing weather, eventually exceeding the planned tolerances. The excessive sags can then cause serious accidents, while hindering the durability of the power lines. We used photogrammetric techniques with a low-cost drone to achieve efficient 3D mapping of power lines that are often difficult to approach. Unlike the conventional image-to-object space approach, we used the object-to-image space approach using cubic grid points. We processed four strips of aerial images to automatically extract the power line points in the object space. Experimental results showed that the approach could successfully extract the positions of the power line points for power line generation and sag measurement with the elevation accuracy of a few centimeters.

3D Power Line Extraction from Multiple Aerial Images

PubMed Central

Lee, Changno

2017-01-01

Power lines are cables that carry electrical power from a power plant to an electrical substation. They must be connected between the tower structures in such a way that ensures minimum tension and sufficient clearance from the ground. Power lines can stretch and sag with the changing weather, eventually exceeding the planned tolerances. The excessive sags can then cause serious accidents, while hindering the durability of the power lines. We used photogrammetric techniques with a low-cost drone to achieve efficient 3D mapping of power lines that are often difficult to approach. Unlike the conventional image-to-object space approach, we used the object-to-image space approach using cubic grid points. We processed four strips of aerial images to automatically extract the power line points in the object space. Experimental results showed that the approach could successfully extract the positions of the power line points for power line generation and sag measurement with the elevation accuracy of a few centimeters. PMID:28961204

Characterization of the disassembly and reassembly of the HBV glycoprotein surface antigen, a pliable nanoparticle vaccine platform.

PubMed

Gallagher, John R; Torian, Udana; McCraw, Dustin M; Harris, Audray K

2017-02-01

While nanoparticle vaccine technology is gaining interest due to the success of vaccines like those for the human papillomavirus that is based on viral capsid nanoparticles, little information is available on the disassembly and reassembly of viral surface glycoprotein-based nanoparticles. One such particle is the hepatitis B virus surface antigen (sAg) that exists as nanoparticles. Here we show, using biochemical analysis coupled with electron microscopy, that sAg nanoparticle disassembly requires both reducing agent to disrupt intermolecular disulfide bonds, and detergent to disrupt hydrophobic interactions that stabilize the nanoparticle. Particles were otherwise resistant to salt and urea, suggesting the driving mechanism of particle formation involves hydrophobic interactions. We reassembled isolated sAg protein into nanoparticles by detergent removal and reassembly resulted in a wider distribution of particle diameters. Knowledge of these driving forces of nanoparticle assembly and stability should facilitate construction of epitope-displaying nanoparticles that can be used as immunogens in vaccines. Published by Elsevier Inc.

Isolation and RFLP genotyping of Toxoplasma gondii from the gray wolf (Canis lupus).

PubMed

Dubey, J P; Choudhary, S; Ferreira, L R; Kwok, O C H; Butler, E; Carstensen, M; Yu, L; Su, C

2013-11-08

Little is known of the genetic diversity of Toxoplasma gondii circulating in wildlife. In the present study feral gray wolves (Canis lupus) from Minnesota were examined for T. gondii infection. Antibodies to T. gondii were detected in 130 (52.4%) of 248 wolves tested by the modified agglutination test (cut-off titer of 25). Tissues (hearts, brains or both) of 109 wolves were bioassayed in mice for protozoal isolation. Viable T. gondii was isolated from 25 and the isolates were further propagated in cell culture. T. gondii DNA from these isolates was characterized using 10 PCR-RFLP markers (SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 and Apico). Four genotypes were detected. Twenty-one isolates were Type 12 (ToxoDB PCR-RFLP genotype #5), 2 were Type II clonal (ToxoDB #1), 1 was Type II variant (ToxoDB #3), and 1 was a new genotype designated as ToxoDB genotype #219. Published by Elsevier B.V.

Intracellular shunting of O{sub 2}{sup −} contributes to charge compensation and preservation of neutrophil respiratory burst in the absence of voltage-gated proton channel activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Decleva, Eva; Menegazzi, Renzo, E-mail: menegazz@units.it; Fasolo, Alba

2013-07-15

Proton efflux via voltage-gated proton channels (Hv1) is considered to mediate the charge compensation necessary to preserve NADPH oxidase activity during the respiratory burst. Using the Hv1 inhibitor Zn{sup 2+}, we found that the PMA-induced respiratory burst of human neutrophils is inhibited when assessed as extracellular production of O{sub 2}{sup −} and H{sub 2}O{sub 2}, in accordance with literature studies, but, surprisingly, unaffected when measured as oxygen consumption or total (extracellular plus intracellular) H{sub 2}O{sub 2} production. Furthermore, we show that inhibiting Hv1 with Zn{sup 2+} results in an increased production of intracellular ROS. Similar results, i.e. decreased extracellular andmore » increased intracellular ROS production, were obtained using a human granulocyte-like cell line with severely impaired Hv1 expression. Acidic extracellular pH, which dampens proton efflux, also augmented intracellular production of H{sub 2}O{sub 2}. Zinc caused an increase in the rate but not in the extent of depolarization and cytosolic acidification indicating that mechanisms other than proton efflux take part in charge compensation. Our results suggest a hitherto unpredicted mechanism of charge compensation whereby, in the absence of proton efflux, part of O{sub 2}{sup −} generated within gp91{sup phox} in the plasma membrane is shunted intracellularly down electrochemical gradient to dampen excessive depolarization. This would preserve NADPH oxidase activity under conditions such as the inflammatory exudate in which the acidic pH hinders charge compensation by proton efflux. Highlights: • Neutrophils’ respiratory burst is not inhibited by the H{sup +} channel inhibitor Zn{sup 2+}. • Intracellular production of O{sub 2}{sup −} and H{sub 2}O{sub 2} is increased in the presence of Zn{sup 2+}. • Intracellular H{sub 2}O{sub 2} production is increased in H{sup +} channels knock-down cells. • Zn{sup 2+} increases the rate but not the extent of depolarization and pH{sub i} decrease. • Intracellular shunting of O{sub 2}{sup −} contributes to charge compensation in neutrophils.« less

Substation Reactive Power Regulation Strategy

NASA Astrophysics Data System (ADS)

Zhang, Junfeng; Zhang, Chunwang; Ma, Daqing

2018-01-01

With the increasing requirements on the power supply quality and reliability of distribution network, voltage and reactive power regulation of substations has become one of the indispensable ways to ensure voltage quality and reactive power balance and to improve the economy and reliability of distribution network. Therefore, it is a general concern of the current power workers and operators that what kind of flexible and effective control method should be used to adjust the on-load tap-changer (OLTC) transformer and shunt compensation capacitor in a substation to achieve reactive power balance in situ, improve voltage pass rate, increase power factor and reduce active power loss. In this paper, based on the traditional nine-zone diagram and combining with the characteristics of substation, a fuzzy variable-center nine-zone diagram control method is proposed and used to make a comprehensive regulation of substation voltage and reactive power. Through the calculation and simulation of the example, this method is proved to have satisfactorily reconciled the contradiction between reactive power and voltage in real-time control and achieved the basic goal of real-time control of the substation, providing a reference value to the practical application of the substation real-time control method.

Modeling and Simulation of Linear and Nonlinear MEMS Scale Electromagnetic Energy Harvesters for Random Vibration Environments

PubMed Central

Sassani, Farrokh

2014-01-01

The simulation results for electromagnetic energy harvesters (EMEHs) under broad band stationary Gaussian random excitations indicate the importance of both a high transformation factor and a high mechanical quality factor to achieve favourable mean power, mean square load voltage, and output spectral density. The optimum load is different for random vibrations and for sinusoidal vibration. Reducing the total damping ratio under band-limited random excitation yields a higher mean square load voltage. Reduced bandwidth resulting from decreased mechanical damping can be compensated by increasing the electrical damping (transformation factor) leading to a higher mean square load voltage and power. Nonlinear EMEHs with a Duffing spring and with linear plus cubic damping are modeled using the method of statistical linearization. These nonlinear EMEHs exhibit approximately linear behaviour under low levels of broadband stationary Gaussian random vibration; however, at higher levels of such excitation the central (resonant) frequency of the spectral density of the output voltage shifts due to the increased nonlinear stiffness and the bandwidth broadens slightly. Nonlinear EMEHs exhibit lower maximum output voltage and central frequency of the spectral density with nonlinear damping compared to linear damping. Stronger nonlinear damping yields broader bandwidths at stable resonant frequency. PMID:24605063

An optimized strain demodulation method for PZT driven fiber Fabry-Perot tunable filter

NASA Astrophysics Data System (ADS)

Sheng, Wenjuan; Peng, G. D.; Liu, Yang; Yang, Ning

2015-08-01

An optimized strain-demodulation-method based on piezo-electrical transducer (PZT) driven fiber Fabry-Perot (FFP) filter is proposed and experimentally demonstrated. Using a parallel processing mode to drive the PZT continuously, the hysteresis effect is eliminated, and the system demodulation rate is increased. Furthermore, an AC-DC compensation method is developed to address the intrinsic nonlinear relationship between the displacement and voltage of PZT. The experimental results show that the actual demodulation rate is improved from 15 Hz to 30 Hz, the random error of the strain measurement is decreased by 95%, and the deviation between the test values after compensation and the theoretical values is less than 1 pm/με.

High power operation of a nitrogen doped, vanadium compensated, 6H-SiC extrinsic photoconductive switch

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sullivan, J. S.

2014-04-28

We report the high power operation of nitrogen doped, vanadium compensated, 6H-SiC, extrinsic photoconductive switches with improved vanadium and nitrogen dopant density. Photoconductive switching tests are performed on 1 mm thick, m-plane, switch substrates at switch voltage and currents up to 17 kV and 1.5 kA, respectively. Sub-ohm minimum switch on resistance is achieved for peak optical intensities ≥35 MW/cm{sup 2} at 532 nm applied to the switch facet. A reduction of greater than nine orders of magnitude is observed in switch material resistivity between dark and illuminated states.

Single-cell genomics reveal metabolic strategies for microbial growth and survival in an oligotrophic aquifer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilkins, Michael J.; Kennedy, David W.; Castelle, Cindy

Bacteria from the genus Pedobacter are a major component of microbial assemblages at Hanford Site and have been shown to significantly change in abundance in response to the subsurface intrusion of Columbia River water. Here we employed single cell genomics techniques to shed light on the physiological niche of these microorganisms. Analysis of four Pedobacter single amplified genomes (SAGs) from Hanford Site sediments revealed a chemoheterotrophic lifestyle, with the potential to exist under both aerobic and microaerophilic conditions via expression of both aa 3­-type and cbb 3-type cytochrome c oxidases. These SAGs encoded a wide-range of both intra-and extra­-cellular carbohydrate-activemore » enzymes, potentially enabling the degradation of recalcitrant substrates such as xylan and chitin, and the utilization of more labile sugars such as mannose and fucose. Coupled to these enzymes, a diversity of transporters and sugar-binding molecules were involved in the uptake of carbon from the extracellular local environment. The SAGs were enriched in TonB-dependent receptors (TBDRs), which play a key role in uptake of substrates resulting from degradation of recalcitrant carbon. CRISPR-Cas mechanisms for resisting viral infections were identified in all SAGs. These data demonstrate the potential mechanisms utilized for persistence by heterotrophic microorganisms in a carbon-limited aquifer, and hint at potential linkages between observed Pedobacter abundance shifts within the 300 Area subsurface and biogeochemical shifts associated with Columbia River water intrusion.« less

The top skin-associated genes: a comparative analysis of human and mouse skin transcriptomes.

PubMed

Gerber, Peter Arne; Buhren, Bettina Alexandra; Schrumpf, Holger; Homey, Bernhard; Zlotnik, Albert; Hevezi, Peter

2014-06-01

The mouse represents a key model system for the study of the physiology and biochemistry of skin. Comparison of skin between mouse and human is critical for interpretation and application of data from mouse experiments to human disease. Here, we review the current knowledge on structure and immunology of mouse and human skin. Moreover, we present a systematic comparison of human and mouse skin transcriptomes. To this end, we have recently used a genome-wide database of human gene expression to identify genes highly expressed in skin, with no, or limited expression elsewhere - human skin-associated genes (hSAGs). Analysis of our set of hSAGs allowed us to generate a comprehensive molecular characterization of healthy human skin. Here, we used a similar database to generate a list of mouse skin-associated genes (mSAGs). A comparative analysis between the top human (n=666) and mouse (n=873) skin-associated genes (SAGs) revealed a total of only 30.2% identity between the two lists. The majority of shared genes encode proteins that participate in structural and barrier functions. Analysis of the top functional annotation terms revealed an overlap for morphogenesis, cell adhesion, structure, and signal transduction. The results of this analysis, discussed in the context of published data, illustrate the diversity between the molecular make up of skin of both species and grants a probable explanation, why results generated in murine in vivo models often fail to translate into the human.

SEROPREVALENCE AND GENETIC CHARACTERIZATION OF TOXOPLASMA GONDII IN NATURALLY-INFECTED SYNANTHROPIC RODENTS IN YUNNAN PROVINCE, SOUTHWESTERN CHINA.

PubMed

Wang, Xin-Lei; Dong, Ling; Zhang, Li; Lv, Yan; Li, Qian; Li, Hailong

2018-05-03

Rodents play important rule in the transmission of Toxoplasma gondii, however, little is known of the seroprevalence and genetic diversity of T. gondii infection in rodents in Yunnan, southwestern China. In this study, we examined the seroprevalence and genetically characterized T. gondii infection in naturally-infected rodents in Yunnan Province, southwestern China between March and July 2016. A total of 261 serum samples were collected from rodents in Jingha district, Xishuangbanna Dai Autonomous Prefecture, Yunnan province, and examined for T. gondii antibodies by modified agglutination test (MAT) at a 1:20 cut-off, with titers of 1:20 in 24, 1:40 in 10, 1:80 in 10, 1:160 in 4. Thirty-two of 261 (12.26%) serum samples were positive for T. gondii by MAT. A total of 751 rodent brain samples were examined by semi-nested-PCR, 46 (6.13%) were positive for the T. gondii B1 gene, 2 of them showed complete genotyping results for all 11 polymorphic loci (SAG1, SAG2, alt.SAG2, SAG3, BTUB, GRA6, L358, PK1, C22-8, C29-2 and Apico). The two samples were characterized to represent ToxoDB Genotype #137 (http://toxodb.org/toxo/). These findings enriched the epidemiological and genetic diversity of T. gondii in China, and implications for the better prevention and control of T. gondii infection in humans and animals.

Networking Senescence-Regulating Pathways by Using Arabidopsis Enhancer Trap Lines1

PubMed Central

He, Yuehui; Tang, Weining; Swain, Johnnie D.; Green, Anthony L.; Jack, Thomas P.; Gan, Susheng

2001-01-01

The last phase of leaf development, generally referred to as leaf senescence, is an integral part of plant development that involves massive programmed cell death. Due to a sharp decline of photosynthetic capacity in a leaf, senescence limits crop yield and forest plant biomass production. However, the biochemical components and regulatory mechanisms underlying leaf senescence are poorly characterized. Although several approaches such as differential cDNA screening, differential display, and cDNA subtraction have been employed to isolate senescence-associated genes (SAGs), only a limited number of SAGs have been identified, and information regarding the regulation of these genes is fragmentary. Here we report on the utilization of enhancer trap approach toward the identification and analysis of SAGs. We have developed a sensitive large-scale screening method and have screened 1,300 Arabidopsis enhancer trap lines and have identified 147 lines in which the reporter gene GUS (β-glucuronidase) is expressed in senescing leaves but not in non-senescing ones. We have systematically analyzed the regulation of β-glucuronidase expression in 125 lines (genetically, each contains single T-DNA insertion) by six senescence-promoting factors, namely abscisic acid, ethylene, jasmonic acid, brassinosteroid, darkness, and dehydration. This analysis not only reveals the complexity of the regulatory circuitry but also allows us to postulate the existence of a network of senescence-promoting pathways. We have also cloned three SAGs from randomly selected enhancer trap lines, demonstrating that reporter expression pattern reflects the expression pattern of the endogenous gene. PMID:11402199

Genetic Characterization of Toxoplasma gondii from Zoo Wildlife and Pet Birds in Fujian, China

PubMed Central

CHEN, Renfeng; LIN, Xuan; HU, Lingying; CHEN, Xiaoli; TANG, Yao; ZHANG, Jia; CHEN, Meizhen; WANG, Shoukun; HUANG, Cuiqin

2015-01-01

Background: Toxoplasmosis, a worldwide zoonotic disease, is caused by Toxoplasma gondii. The distribution of genetic diversity of T. gondii in wild animals is of great importance to understand the transmission of the parasite in the environment. However, little is known about T. gondii prevalence in wild animals and birds in China. Methods: We conducted the genetic characterization of T. gondii isolated from Zoo Wild Animals and Pet Birds in Fujian Province, Southeastern China. Heart tissues were collected from 45 zoo animals and 140 pet birds. After identified using B1 gene, the genetic diversity of T. gondii isolates were typed at 11 genetic markers, including SAG1, 5’ and 3’-SAG2, alternative SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, Apico, and CS3. Results: Seven of 45 zoo animals and 3 of 140 pet birds were positive by PCR amplification using T. gondii B1 gene specific primers. Of these positive isolates, 3 isolates from Black-capped (Cebus apella), Peacock (Peafowl) and Budgerigar (Melopsittacus undulatus) were successfully genotyped at 11 genetic loci, and grouped to three distinct genotypes: ToxoDB Genotype #9, #2 and #10, respectively. Conclusion: This is the first genotyping of T. gondii isolated from zoo wild animals and pet birds in Fujian, China. There is a potential risk for the transmission of this parasite through zoo wild animals and pet birds in this region. PMID:26811736

Genetic Characterization of Toxoplasma gondii from Zoo Wildlife and Pet Birds in Fujian, China.

PubMed

Chen, Renfeng; Lin, Xuan; Hu, Lingying; Chen, Xiaoli; Tang, Yao; Zhang, Jia; Chen, Meizhen; Wang, Shoukun; Huang, Cuiqin

2015-01-01

Toxoplasmosis, a worldwide zoonotic disease, is caused by Toxoplasma gondii. The distribution of genetic diversity of T. gondii in wild animals is of great importance to understand the transmission of the parasite in the environment. However, little is known about T. gondii prevalence in wild animals and birds in China. We conducted the genetic characterization of T. gondii isolated from Zoo Wild Animals and Pet Birds in Fujian Province, Southeastern China. Heart tissues were collected from 45 zoo animals and 140 pet birds. After identified using B1 gene, the genetic diversity of T. gondii isolates were typed at 11 genetic markers, including SAG1, 5' and 3'-SAG2, alternative SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, Apico, and CS3. Seven of 45 zoo animals and 3 of 140 pet birds were positive by PCR amplification using T. gondii B1 gene specific primers. Of these positive isolates, 3 isolates from Black-capped (Cebus apella), Peacock (Peafowl) and Budgerigar (Melopsittacus undulatus) were successfully genotyped at 11 genetic loci, and grouped to three distinct genotypes: ToxoDB Genotype #9, #2 and #10, respectively. This is the first genotyping of T. gondii isolated from zoo wild animals and pet birds in Fujian, China. There is a potential risk for the transmission of this parasite through zoo wild animals and pet birds in this region.

Occurrence, isolation, and genetic characterization of Toxoplasma gondii from white-tailed deer (Odocoileus virginianus) in New Jersey.

PubMed

Dubey, J P; Randall, A R; Choudhary, S; Ferreira, L R; Verma, S K; Oliveira, S; Kwok, O C H; Su, C

2013-10-01

The ingestion of uncooked infected white-tailed deer (WTD) tissues can transmit Toxoplasma gondii infection to humans and mesocarnivores, including cats. In the present study, we tested 264 WTD from New Jersey for T. gondii infection during the 2011-2012 hunting season. Serum samples were tested for antibodies to T. gondii by the modified agglutination test (cutoff titer, 25); 76 (28.7%) of 264 WTD were seropositive. Heart muscle samples from 64 seropositive WTD were digested in pepsin, and the digests were bioassayed for the isolation of T. gondii . Viable T. gondii was isolated in mice from the myocardium of 9 WTD; tachyzoites from infected mouse tissues were further propagated in cell culture. One of the 9 strains was highly virulent for outbred Swiss Webster mice. The DNA isolated from culture-derived tachyzoites of these 9 T. gondii isolates was characterized using 11 PCR-RFLP markers (SAG1, 5'- and 3'-SAG2, alt.SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico). Six genotypes were found, including ToxoDB genotype no. 2 (Type III), no. 3 (Type II variant), no. 4 (Type 12), no. 216, no. 220, and no. 221. The last 2 were new genotypes that were reported for the first time. This is the first report of T. gondii infection in deer from this region of the United States.

Hydrocarbon potential evaluation of the source rocks from the Abu Gabra Formation in the Sufyan Sag, Muglad Basin, Sudan

NASA Astrophysics Data System (ADS)

Qiao, Jinqi; Liu, Luofu; An, Fuli; Xiao, Fei; Wang, Ying; Wu, Kangjun; Zhao, Yuanyuan

2016-06-01

The Sufyan Sag is one of the low-exploration areas in the Muglad Basin (Sudan), and hydrocarbon potential evaluation of source rocks is the basis for its further exploration. The Abu Gabra Formation consisting of three members (AG3, AG2 and AG1 from bottom to top) was thought to be the main source rock formation, but detailed studies on its petroleum geology and geochemical characteristics are still insufficient. Through systematic analysis on distribution, organic matter abundance, organic matter type, organic matter maturity and characteristics of hydrocarbon generation and expulsion of the source rocks from the Abu Gabra Formation, the main source rock members were determined and the petroleum resource extent was estimated in the study area. The results show that dark mudstones are the thickest in the AG2 member while the thinnest in the AG1 member, and the thickness of the AG3 dark mudstone is not small either. The AG3 member have developed good-excellent source rock mainly with Type I kerogen. In the Southern Sub-sag, the AG3 source rock began to generate hydrocarbons in the middle period of Bentiu. In the early period of Darfur, it reached the hydrocarbon generation and expulsion peak. It is in late mature stage currently. The AG2 member developed good-excellent source rock mainly with Types II1 and I kerogen, and has lower organic matter abundance than the AG3 member. In the Southern Sub-sag, the AG2 source rock began to generate hydrocarbons in the late period of Bentiu. In the late period of Darfur, it reached the peak of hydrocarbon generation and its expulsion. It is in middle mature stage currently. The AG1 member developed fair-good source rock mainly with Types II and III kerogen. Throughout the geological evolution history, the AG1 source rock has no effective hydrocarbon generation or expulsion processes. Combined with basin modeling results, we have concluded that the AG3 and AG2 members are the main source rock layers and the Southern Sub-sag is the main source kitchen in the study area. The AG3 and AG2 source rocks have supplied 58.1% and 41.9% of the total hydrocarbon generation, respectively, and 54.9% and 45.1% of the total hydrocarbon expulsion, respectively. Their hydrocarbon expulsion efficiency ratios are 71.0% and 62.3%, respectively. The Southern Sub-sag has supplied more than 90% of the total amounts of hydrocarbon generation and its expulsion.

Monolithic amplifier with stable, high resistance feedback element and method for fabricating the same

DOEpatents

O`Connor, P.

1998-08-11

A monolithic amplifier includes a stable, high resistance feedback circuit and a dynamic bias circuit. The dynamic bias circuit is formed with active elements matched to those in the amplifier and feedback circuit to compensate for variations in the operating and threshold voltages thereby maintaining a stable resistance in the feedback circuit. 11 figs.

Electronic control circuits: A compilation

NASA Technical Reports Server (NTRS)

1973-01-01

A compilation of technical R and D information on circuits and modular subassemblies is presented as a part of a technology utilization program. Fundamental design principles and applications are given. Electronic control circuits discussed include: anti-noise circuit; ground protection device for bioinstrumentation; temperature compensation for operational amplifiers; hybrid gatling capacitor; automatic signal range control; integrated clock-switching control; and precision voltage tolerance detector.

Aquarius Digital Processing Unit

NASA Technical Reports Server (NTRS)

Forgione, Joshua; Winkert, George; Dobson, Norman

2009-01-01

Three documents provide information on a digital processing unit (DPU) for the planned Aquarius mission, in which a radiometer aboard a spacecraft orbiting Earth is to measure radiometric temperatures from which data on sea-surface salinity are to be deduced. The DPU is the interface between the radiometer and an instrument-command-and-data system aboard the spacecraft. The DPU cycles the radiometer through a programmable sequence of states, collects and processes all radiometric data, and collects all housekeeping data pertaining to operation of the radiometer. The documents summarize the DPU design, with emphasis on innovative aspects that include mainly the following: a) In the radiometer and the DPU, conversion from analog voltages to digital data is effected by means of asynchronous voltage-to-frequency converters in combination with a frequency-measurement scheme implemented in field-programmable gate arrays (FPGAs). b) A scheme to compensate for aging and changes in the temperature of the DPU in order to provide an overall temperature-measurement accuracy within 0.01 K includes a high-precision, inexpensive DC temperature measurement scheme and a drift-compensation scheme that was used on the Cassini radar system. c) An interface among multiple FPGAs in the DPU guarantees setup and hold times.

Performance of low-voltage STEM/TEM with delta corrector and cold field emission gun.

PubMed

Sasaki, Takeo; Sawada, Hidetaka; Hosokawa, Fumio; Kohno, Yuji; Tomita, Takeshi; Kaneyama, Toshikatsu; Kondo, Yukihito; Kimoto, Koji; Sato, Yuta; Suenaga, Kazu

2010-08-01

To reduce radiation damage caused by the electron beam and to obtain high-contrast images of specimens, we have developed a highly stabilized transmission electron microscope equipped with a cold field emission gun and spherical aberration correctors for image- and probe-forming systems, which operates at lower acceleration voltages than conventional transmission electron microscopes. A delta-type aberration corrector is designed to simultaneously compensate for third-order spherical aberration and fifth-order 6-fold astigmatism. Both were successfully compensated in both scanning transmission electron microscopy (STEM) and transmission electron microscopy (TEM) modes in the range 30-60 kV. The Fourier transforms of raw high-angle annular dark field (HAADF) images of a Si[110] sample revealed spots corresponding to lattice spacings of 111 and 96 pm at 30 and 60 kV, respectively, and those of raw TEM images of an amorphous Ge film with gold particles showed spots corresponding to spacings of 91 and 79 pm at 30 and 60 kV, respectively. Er@C(82)-doped single-walled carbon nanotubes, which are carbon-based samples, were successfully observed by HAADF-STEM imaging with an atomic-level resolution.

Separation and Identification of Isomeric Glycopeptides by High Field Asymmetric Waveform Ion Mobility Spectrometry

PubMed Central

2012-01-01

The analysis of intact glycopeptides by mass spectrometry is challenging due to the numerous possibilities for isomerization, both within the attached glycan and the location of the modification on the peptide backbone. Here, we demonstrate that high field asymmetric wave ion mobility spectrometry (FAIMS), also known as differential ion mobility, is able to separate isomeric O-linked glycopeptides that have identical sequences but differing sites of glycosylation. Two glycopeptides from the glycoprotein mucin 5AC, GT(GalNAc)TPSPVPTTSTTSAP and GTTPSPVPTTST(GalNAc)TSAP (where GalNAc is O-linked N-acetylgalactosamine), were shown to coelute following reversed-phase liquid chromatography. However, FAIMS analysis of the glycopeptides revealed that the compensation voltage ranges in which the peptides were transmitted differed. Thus, it is possible at certain compensation voltages to completely separate the glycopeptides. Separation of the glycopeptides was confirmed by unique reporter ions produced by supplemental activation electron transfer dissociation mass spectrometry. These fragments also enable localization of the site of glycosylation. The results suggest that glycan position plays a key role in determining gas-phase glycopeptide structure and have implications for the application of FAIMS in glycoproteomics. PMID:22280549

A Wavelet-based Fast Discrimination of Transformer Magnetizing Inrush Current

NASA Astrophysics Data System (ADS)

Kitayama, Masashi

Recently customers who need electricity of higher quality have been installing co-generation facilities. They can avoid voltage sags and other distribution system related disturbances by supplying electricity to important load from their generators. For another example, FRIENDS, highly reliable distribution system using semiconductor switches or storage devices based on power electronics technology, is proposed. These examples illustrates that the request for high reliability in distribution system is increasing. In order to realize these systems, fast relaying algorithms are indispensable. The author proposes a new method of detecting magnetizing inrush current using discrete wavelet transform (DWT). DWT provides the function of detecting discontinuity of current waveform. Inrush current occurs when transformer core becomes saturated. The proposed method detects spikes of DWT components derived from the discontinuity of the current waveform at both the beginning and the end of inrush current. Wavelet thresholding, one of the wavelet-based statistical modeling, was applied to detect the DWT component spikes. The proposed method is verified using experimental data using single-phase transformer and the proposed method is proved to be effective.

Current limiting remote power control module

NASA Technical Reports Server (NTRS)

Hopkins, Douglas C.

1990-01-01

The power source for the Space Station Freedom will be fully utilized nearly all of the time. As such, any loads on the system will need to operate within expected limits. Should any load draw an inordinate amount of power, the bus voltage for the system may sag and disrupt the operation of other loads. To protect the bus and loads some type of power interface between the bus and each load must be provided. This interface is most crucial when load faults occur. A possible system configuration is presented. The proposed interface is the Current Limiting Remote Power Controller (CL-RPC). Such an interface should provide the following power functions: limit overloading and resulting undervoltage; prevent catastrophic failure and still provide for redundancy management within the load; minimize cable heating; and provide accurate current measurement. A functional block diagram of the power processing stage of a CL-RPC is included. There are four functions that drive the circuit design: rate control of current; current sensing; the variable conductance switch (VCS) technology; and the algorithm used for current limiting. Each function is discussed separately.

Method to Eliminate Flux Linkage DC Component in Load Transformer for Static Transfer Switch

PubMed Central

2014-01-01

Many industrial and commercial sensitive loads are subject to the voltage sags and interruptions. The static transfer switch (STS) based on the thyristors is applied to improve the power quality and reliability. However, the transfer will result in severe inrush current in the load transformer, because of the DC component in the magnetic flux generated in the transfer process. The inrush current which is always 2~30 p.u. can cause the disoperation of relay protective devices and bring potential damage to the transformer. The way to eliminate the DC component is to transfer the related phases when the residual flux linkage of the load transformer and the prospective flux linkage of the alternate source are equal. This paper analyzes how the flux linkage of each winding in the load transformer changes in the transfer process. Based on the residual flux linkage when the preferred source is completely disconnected, the method to calculate the proper time point to close each phase of the alternate source is developed. Simulation and laboratory experiments results are presented to show the effectiveness of the transfer method. PMID:25133255

Method to eliminate flux linkage DC component in load transformer for static transfer switch.

PubMed

He, Yu; Mao, Chengxiong; Lu, Jiming; Wang, Dan; Tian, Bing

2014-01-01

Many industrial and commercial sensitive loads are subject to the voltage sags and interruptions. The static transfer switch (STS) based on the thyristors is applied to improve the power quality and reliability. However, the transfer will result in severe inrush current in the load transformer, because of the DC component in the magnetic flux generated in the transfer process. The inrush current which is always 2 ~ 30 p.u. can cause the disoperation of relay protective devices and bring potential damage to the transformer. The way to eliminate the DC component is to transfer the related phases when the residual flux linkage of the load transformer and the prospective flux linkage of the alternate source are equal. This paper analyzes how the flux linkage of each winding in the load transformer changes in the transfer process. Based on the residual flux linkage when the preferred source is completely disconnected, the method to calculate the proper time point to close each phase of the alternate source is developed. Simulation and laboratory experiments results are presented to show the effectiveness of the transfer method.

Melt Electrowriting of Thermoplastic Elastomers.

PubMed

Hochleitner, Gernot; Fürsattel, Eva; Giesa, Reiner; Groll, Jürgen; Schmidt, Hans-Werner; Dalton, Paul D

2018-04-14

Melt electrowriting (MEW), an additive manufacturing process, is established using polycaprolactone as the benchmark material. In this study, a thermoplastic elastomer, namely, poly(urea-siloxane), is synthesized and characterized to identify how different classes of polymers are compatible with MEW. This polyaddition polymer has reversible hydrogen bonding from the melt upon heating/cooling and highly resolved structures are achieved by MEW. The influence of applied voltage, temperature, and feeding pressure on printing outcomes behavior is optimized. Balancing these parameters, highly uniform and smooth-surfaced fibers with diameters ranging from 10 to 20 µm result. The quality of the 3D MEW scaffolds is excellent, with very accurate fiber stacking capacity-up to 50 layers with minimal defects and good fiber fusion between the layers. There is also minimal fiber sagging between the crossover points, which is a characteristic of thicker MEW scaffolds previously reported with other polymers. In summary, poly(urea-siloxane) demonstrates outstanding compatibility with the MEW process and represents a class of polymer-thermoplastic elastomers-that are, until now, untested with this approach. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A new approach to power quality and electricity reliability monitoring-case study illustrations of the capabilities of the I-GridTM system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Divan, Deepak; Brumsickle, William; Eto, Joseph

2003-04-01

This report describes a new approach for collecting information on power quality and reliability and making it available in the public domain. Making this information readily available in a form that is meaningful to electricity consumers is necessary for enabling more informed private and public decisions regarding electricity reliability. The system dramatically reduces the cost (and expertise) needed for customers to obtain information on the most significant power quality events, called voltage sags and interruptions. The system also offers widespread access to information on power quality collected from multiple sites and the potential for capturing information on the impacts ofmore » power quality problems, together enabling a wide variety of analysis and benchmarking to improve system reliability. Six case studies demonstrate selected functionality and capabilities of the system, including: Linking measured power quality events to process interruption and downtime; Demonstrating the ability to correlate events recorded by multiple monitors to narrow and confirm the causes of power quality events; and Benchmarking power quality and reliability on a firm and regional basis.« less

Matrix Converter Interface for a Wind Energy Conversion System: Issues and Limitations

NASA Astrophysics Data System (ADS)

Patki, Chetan; Agarwal, Vivek

2009-08-01

Variable speed grid connected wind energy systems sometimes involve AC-AC power electronic interface between the generator and the grid. Matrix converter is an attractive option for such applications. Variable speed of the wind generator demands variable voltage variable frequency at the generator terminal. Matrix converter is used in this work to generate such a supply. Also, matrix converter can be appropriately controlled to compensate the grid for non-linear, reactive loads. However, any change of power factor on the grid side reflects on the voltage magnitude on the wind generator side. It is highlighted that this may contradict the maximum power point tracking control requirements. All the results of this work are presented.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chinthavali, Madhu Sudhan; Campbell, Steven L

This paper presents an analytical model for wireless power transfer system used in electric vehicle application. The equivalent circuit model for each major component of the system is described, including the input voltage source, resonant network, transformer, nonlinear diode rectifier load, etc. Based on the circuit model, the primary side compensation capacitance, equivalent input impedance, active / reactive power are calculated, which provides a guideline for parameter selection. Moreover, the voltage gain curve from dc output to dc input is derived as well. A hardware prototype with series-parallel resonant stage is built to verify the developed model. The experimental resultsmore » from the hardware are compared with the model predicted results to show the validity of the model.« less

A new LTPS TFT AC pixel circuit for an AMOLED

NASA Astrophysics Data System (ADS)

Yongwen, Zhang; Wenbin, Chen

2013-01-01

This work presents a new voltage programmed pixel circuit for an active-matrix organic light-emitting diode (AMOLED) display. The proposed pixel circuit consists of six low temperature polycrystalline silicon thin-film transistors (LTPS TFTs), one storage capacitor, and one OLED, and is verified by simulation work using HSPICE software. Besides effectively compensating for the threshold voltage variation of the driving TFT and OLED, the proposed pixel circuit offers an AC driving mode for the OLED, which can suppress the degradation of the OLED. Moreover, a high contrast ratio can be achieved by the proposed pixel circuit since the OLED does not emit any light except for the emission period.

Optical fiber voltage sensors for broad temperature ranges

NASA Technical Reports Server (NTRS)

Rose, A. H.; Day, G. W.

1992-01-01

We describe the development of an optical fiber ac voltage sensor for aircraft and spacecraft applications. Among the most difficult specifications to meet for this application is a temperature stability of +/- 1 percent from -65 C to +125 C. This stability requires a careful selection of materials, components, and optical configuration with further compensation using an optical-fiber temperature sensor located near the sensing element. The sensor is a polarimetric design, based on the linear electro-optic effect in bulk Bi4Ge3O12. The temperature sensor is also polarimetric, based on the temperature dependence of the birefringence of bulk SiO2. The temperature sensor output is used to automatically adjust the calibration of the instrument.

Electron-Optical System of the Gyrotron Designed for Operation in the DNP-NMR Spectrometer Cryomagnet ("Gyrotrino")

NASA Astrophysics Data System (ADS)

Bratman, V. L.; Fedotov, A. E.; Kalynov, Yu. K.; Manuilov, V. N.

2017-08-01

The formation and utilization of a helical electron beam are studied theoretically for a gyrotron with a very low operating voltage in a range 1.5-1.8 kV. Such a gyrotron ("gyrotrino") was earlier proposed for operation inside a magnetic system of an NMR spectrometer with a dynamic nuclear polarization upgrade. Despite the very low voltage, the optimization of the electrode shape can provide velocity and positional electron spreads not exceeding these values for conventional high-voltage gyrotrons. A very small cathode-anode separation makes the gyrotrino very sensitive to thermal expansion of the gun elements that should be compensated by movement of the cathode. Estimations for long-pulse and CW regimes of the gyrotrino operation show that the ion background significantly decreases the reduction of the beam potential and leads to an acceptable drift of the electron cyclotron frequency at the voltage front. A satisfactory thermal load on the waste-beam collector located in a strong uniform magnetic field can be achieved due to the omnidirectional heat flow regime occurring in the case of thin beam footprint.

DOE Office of Scientific and Technical Information (OSTI.GOV)

MacMartin, Douglas G.; Kravitz, Ben; Long, Jane C. S.

Any well-informed future decision on whether and how to deploy solar geoengineering requires balancing the impacts (both intended and unintended) of intervening in the climate against the impacts of not doing so. In spite of the tremendous progress in the last decade, the current state of knowledge remains insufficient to support an assessment of this balance, even for stratospheric aerosol geoengineering (SAG), arguably the best understood (practical) geoengineering method. We then articulate key unknowns associated with SAG, including both climate-science and design questions, as an essential step toward developing a future strategic research program that could address outstanding uncertainties.

Cryogenic Scan Mechanism for Fourier Transform Spectrometer

NASA Technical Reports Server (NTRS)

Brasunas, John C.; Francis, John L.

2011-01-01

A compact and lightweight mechanism has been developed to accurately move a Fourier transform spectrometer (FTS) scan mirror (a cube corner) in a near-linear fashion with near constant speed at cryogenic temperatures. This innovation includes a slide mechanism to restrict motion to one dimension, an actuator to drive the motion, and a linear velocity transducer (LVT) to measure the speed. The cube corner mirror is double-passed in one arm of the FTS; double-passing is required to compensate for optical beam shear resulting from tilting of the moving cube corner. The slide, actuator, and LVT are off-the-shelf components that are capable of cryogenic vacuum operation. The actuator drives the slide for the required travel of 2.5 cm. The LVT measures translation speed. A proportional feedback loop compares the LVT voltage with the set voltage (speed) to derive an error signal to drive the actuator and achieve near constant speed. When the end of the scan is reached, a personal computer reverses the set voltage. The actuator and LVT have no moving parts in contact, and have magnetic properties consistent with cryogenic operation. The unlubricated slide restricts motion to linear travel, using crossed roller bearings consistent with 100-million- stroke operation. The mechanism tilts several arc seconds during transport of the FTS mirror, which would compromise optical fringe efficiency when using a flat mirror. Consequently, a cube corner mirror is used, which converts a tilt into a shear. The sheared beam strikes (at normal incidence) a flat mirror at the end of the FTS arm with the moving mechanism, thereby returning upon itself and compensating for the shear

Design of active temperature compensated composite free-free beam MEMS resonators in a standard process

NASA Astrophysics Data System (ADS)

Xereas, George; Chodavarapu, Vamsy P.

2014-03-01

Frequency references are used in almost every modern electronic device including mobile phones, personal computers, and scientific and medical instrumentation. With modern consumer mobile devices imposing stringent requirements of low cost, low complexity, compact system integration and low power consumption, there has been significant interest to develop batch-manufactured MEMS resonators. An important challenge for MEMS resonators is to match the frequency and temperature stability of quartz resonators. We present 1MHz and 20MHz temperature compensated Free-Free beam MEMS resonators developed using PolyMUMPS, which is a commercial multi-user process available from MEMSCAP. We introduce a novel temperature compensation technique that enables high frequency stability over a wide temperature range. We used three strategies: passive compensation by using a structural gold (Au) layer on the resonator, active compensation through using a heater element, and a Free-Free beam design that minimizes the effects of thermal mismatch between the vibrating structure and the substrate. Detailed electro-mechanical simulations were performed to evaluate the frequency response and Quality Factor (Q). Specifically, for the 20MHz device, a Q of 10,000 was obtained for the passive compensated design. Finite Element Modeling (FEM) simulations were used to evaluate the Temperature Coefficient of frequency (TCf) of the resonators between -50°C and 125°C which yielded +0.638 ppm/°C for the active compensated, compared to -1.66 ppm/°C for the passively compensated design and -8.48 ppm/°C for uncompensated design for the 20MHz device. Electro-thermo-mechanical simulations showed that the heater element was capable of increasing the temperature of the resonators by approximately 53°C with an applied voltage of 10V and power consumption of 8.42 mW.

A low-angle normal fault and basement structures within the Enping Sag, Pearl River Mouth Basin: Insights into late Mesozoic to early Cenozoic tectonic evolution of the South China Sea area

NASA Astrophysics Data System (ADS)

Ye, Qing; Mei, Lianfu; Shi, Hesheng; Shu, Yu; Camanni, Giovanni; Wu, Jing

2018-04-01

The basement structure of the Cenozoic Enping Sag, within the Pearl River Mouth Basin on the northern margin of South China Sea, is revealed by borehole-constrained high-quality 3D seismic reflection data. Such data suggest that the Enping Sag is bounded in the north by a low-angle normal fault. We interpret this low-angle normal fault to have developed as the result of the reactivation of a pre-existing thrust fault part of a pre-Cenozoic thrust system. This is demonstrated by the selective reactivation of the pre-existing thrust and by diffuse contractional deformation recognized from the accurate analysis of basement reflections. Another significant result of this study is the finding of some residual rift basins within the basement of the Enping Sag. Both the thrust system and the residual basins are interpreted to have developed after the emplacement of continental margin arc-related granitoids (J3-K1) that define the basement within the study area. Furthermore, seismic sections show that the pre-existing residual rift basins are offset by the main thrust fault and they are both truncated by the Tg unconformity. These structural relationships, interpreted in the frame of previous studies, help us to reconstruct a six-event structural evolution model for the Enping Sag from the late Mesozoic to the early Cenozoic. In particular, we interpret the residual rift basins to have formed as the result of back-arc extension due to the slab roll-back of the Paleo-Pacific Plate subduction in the early K2. The thrust system has recorded a compressional event in the late K2 that followed the back-arc extension in the SCS area. The mechanism of this compressional event is still to be clarified, and might be related to continuous subduction of the Paleo-Pacific Plate or to the continent-continent collision between a micro-continental block and the South China margin.

A Neospora caninum vaccine using recombinant proteins fails to prevent foetal infection in pregnant cattle after experimental intravenous challenge.

PubMed

Hecker, Yanina P; Cóceres, Verónica; Wilkowsky, Silvina E; Jaramillo Ortiz, José M; Morrell, Eleonora L; Verna, Andrea E; Ganuza, Agustina; Cano, Dora B; Lischinsky, Lilian; Angel, Sergio O; Zamorano, Patricia; Odeón, Anselmo C; Leunda, María R; Campero, Carlos M; Morein, Bror; Moore, Dadín P

2014-12-15

The aim of the present study was to evaluate the immunogenicity and protective efficacy of rNcSAG1, rNcHSP20 and rNcGRA7 recombinant proteins formulated with immune stimulating complexes (ISCOMs) in pregnant heifers against vertical transmission of Neospora caninum. Twelve pregnant heifers were divided into 3 groups of 4 heifers each, receiving different formulations before mating. Immunogens were administered twice subcutaneously: group A animals were inoculated with three recombinant proteins (rNcSAG1, rNcHSP20, rNcGRA7) formulated with ISCOMs; group B animals received ISCOM-MATRIX (without antigen) and group C received sterile phosphate-buffered saline (PBS) only. The recombinant proteins were expressed in Escherichia coli and purified nickel resin. All groups were intravenously challenged with the NC-1 strain of N. caninum at Day 70 of gestation and dams slaughtered at week 17 of the experiment. Heifers from group A developed specific antibodies against rNcSAG1, rNcHSP20 and rNcGRA7 prior to the challenge. Following immunization, an statistically significant increase of antibodies against rNcSAG1 and rNcHSP20 in all animals of group A was detected compared to animals in groups B and C at weeks 5, 13 and 16 (P<0.001). Levels of antibodies against rNcGRA7 were statistical higher in group A animals when compared with groups B and C at weeks 5 and 16 (P>0.001). There were no differences in IFN-γ production among the experimental groups at any time point (P>0.05). Transplacental transmission was determined in all foetuses of groups A, B and C by Western blot, immunohistochemistry and nested PCR. This work showed that rNcSAG1, rNcHSP20 and rNcGRA7 proteins while immunogenic in cattle failed to prevent the foetal infection in pregnant cattle challenged at Day 70 of gestation. Copyright © 2014 Elsevier B.V. All rights reserved.

Isolation of viable Toxoplasma gondii, molecular characterization, and seroprevalence in elk (Cervus canadensis) in Pennsylvania, USA.

PubMed

Dubey, J P; Brown, J; Verma, S K; Cerqueira-Cézar, C K; Banfield, J; Kwok, O C H; Ying, Y; Murata, F H A; Pradhan, A K; Su, C

2017-08-30

Toxoplasmosis is a worldwide zoonosis. The ingestion of uncooked/undercooked meat and consumption of water contaminated with Toxoplasma gondii oocysts excreted by felids are the main modes of transmission of this parasite. T. gondii has been reported in multiple cervid species; however, little is known of the parasite in North American elk (Cervus canadensis). In the present study, antibodies to T. gondii were detected in serum of wild elk from Pennsylvania collected during 2013-2016 by the modified agglutination test (MAT, cut-off 1:25); 221 of 317 (69.7%) had MAT titers of 1:25 in 19, 1:50 in 28, 1:100 in 34, and 1:200 or higher in 140. Thus most (44.1%) elk had relatively high titers. Seroprevalence was slightly higher in males (76.9%) than females (67.5%, not statistically significant, Chi-square tests, P<0.0001) and was higher in adults (76.5%) than yearlings (46.4%, Odds ratio 3.82; 95% CL 1.72-8.47; P=0.001) or calves (21.7%, Odds ratio 12.58; 95% CL 4.51-35.10; P<0.0001). Annual seroprevalence was relatively stable throughout the period tested and ranged from 66.6% to 72.2%. Of the 101 elk harvested in 2016, hearts were bioassayed from 20 elk and tongues were bioassayed from 56; all tongue samples were negative. Viable T. gondii was isolated from hearts of two female elk, one of these was a seronegative adult and the other was a calf with no serum available for testing. Both T. gondii isolates were cultivated in cell culture and DNA derived from tachyzoites was characterized using the PCR-RFLP markers including SAG1, SAG2 (5'- 3'SAG2 and altSAG2), SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico. One isolate belongs to ToxoDB PCR-RFLP genotype #2 and the other is genotype #5. Both genotypes are frequently identified in animals in North America. Copyright © 2017. Published by Elsevier B.V.

SU-G-BRB-09: Kompeito-Shot: Development of a Novel Verification System for 3D Beam Alignment Including the Sag of Gantry Head

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsuneda, M; Nishio, T; Saito, A

Purpose: High accuracy of beam axis is required for high-precision radiation therapy. It is impossible to quantitatively and directly evaluate the sagging effect of the gantry head using current methods (star-shot and Winston-Lutz tests) when the gantry head sags under the weight of MLC and X-Y jaws. We introduce a novel method “Kompeito-shot (3D star-shot)” for the verification of 3D beam alignment (3D isocentricity). This method enables direct measurement of the sagging effect. We developed the system and examined the concept of this system. Methods: The system composed of a plastic scintillator (PS), a truncated cone-shaped mirror, a plane mirrormore » and a CCD camera. Two types of PS were compared. One consisted of a column PS (Co system), the other consisted of a column PS inserted into a barrel PS with shading film in between (Co-Ba system). The system was irradiated with a 6-MV photon beam and the scintillation light was measured using the CCD camera through the mirror system. The gantry angle was set from 270 to 300 degrees to mimic the sagging of the gantry head for evaluating the accuracy of the system. The distance between a center of PS and entrance / exit points were calculated to analyze the gantry angle. And, the calculated gantry angle and the irradiated gantry angle were compared. Results: We compared the measured image of Co system and that of Co-Ba system. Entrance and exit areas were visualized clearly. The histogram showing the difference between the calculated gantry angle and the irradiated gantry angle was fitted with a Gaussian function. Mean and standard deviation of Co-Ba system were smaller than that of Co system by one order of magnitude. Conclusion: We developed the Kompeito-shot system and evaluated the accuracy of the system. The basic concept works for the verification of 3D isocentricity.« less

Toxoplasmosis in the Caribbean islands: literature review, seroprevalence in pregnant women in ten countries, isolation of viable Toxoplasma gondii from dogs from St. Kitts, West Indies with report of new T. gondii genetic types.

PubMed

Dubey, Jitender P; Verma, Shiv Kumar; Villena, Isabelle; Aubert, Dominique; Geers, Régine; Su, Chunlei; Lee, Elise; Forde, Martin S; Krecek, Rosina C

2016-04-01

Little is currently known of clinical toxoplasmosis in humans and animals in the Caribbean. We investigated the prevalence of IgG and IgM antibodies in 437 pregnant women from 10 English speaking Caribbean countries. Overall, antibodies (IgG) to Toxoplasma gondii (modified agglutination test, MAT, cut-off 1:6) were found in 174 (39.8 %) of 437 human sera; specifically 12 of 38 from Antigua-Barbuda, 26 of 52 from Belize, 9 of 50 from Bermuda, 29 of 49 from Dominica, 18 of 49 from Grenada, 16 of 47 from Jamaica, 5 of 15 from Montserrat, 8 of 44 from St. Kitts/Nevis, 24 of 45 from St. Lucia, and 27 of 50 from St. Vincent/Grenadines were seropositive. All IgG-positive sera were tested for IgM antibodies using the immunocapture method; all sera were negative for IgM antibodies. Additionally, tissues and sera of 45 dogs from St. Kitts were examined for T. gondii infection. Antibodies (IgG, MAT, 1:≥25) were found in 19 (42.2 %) of 45 dogs. Muscle samples (tongue, leg) of 19 seropositive dogs were digested in pepsin, and homogenates were bioassayed in mice. Viable T. gondii were isolated from 6 dogs. T. gondii isolates were further propagated in cell culture. PCR-RFLP genotyping of cell culture derived tachyzoites using 10 genetic markers, SAG1, SAG2 (5' and 3' SAG2, and alt.SAG2) SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico revealed that 4 isolates were ToxoDB PCR-RFLP genotype #2, and 2 were new genotypes #264 and #265. Review of 22 viable T. gondii isolates from chickens, dogs, and cats from Grenada and St. Kitts revealed that 1 isolate was type II, 13 were type III, and 8 were atypical. Thus, type III strains were predominant. Overall, the study revealed high prevalence of T. gondii in the Caribbean islands.

Microevolutionary dynamics in Methanothermococcus populations from deep-sea hydrothermal vents in the Mid-Cayman Rise

NASA Astrophysics Data System (ADS)

Hoffert, M.; Anderson, R. E.; Stepanauskas, R.; Huber, J. A.

2017-12-01

Deep-sea hydrothermal vents sustain diverse communities of microorganisms. The effects of geochemical and biological interactions on the process of evolution in these ecosystems remains poorly understood because the majority of subsurface microorganisms remain uncultivated. By examining metagenomic samples from hydrothermal fluids and mapping the samples to closely-related genomes found in vent sites, we can better understand how the process of evolution is affected by the geochemical and environmental context in deep-sea vents. The Mid-Cayman Rise is a spreading ridge that hosts both mafic-influenced and ultramafic-influenced vent fields. Previous research on metagenomic samples from sites in the Mid-Cayman Rise has shown that these vents contain metabolically and taxonomically diverse microbial communities. Here, we investigate five single cell amplified Methanothermococcus genomes (SAGs) to investigate patterns in pangenomic variation and molecular evolution in these methanogens. Mappings of metagenomic reads from 15 sample sites to the SAGs reveal substantial variation in Methanothermococcus population abundance, nucleotide variability and selection pressure among the 15 geochemically distinct sample sites. Within each sample site, we observed distinct patterns of single nucleotide variant (SNV) accumulation and selection pressure within the SAG populations. Closely related genomes showed similar patterns of SNV accumulation. Analysis of open reading frames (ORFs) from the SAGs indicated that homologous genes accumulated variation at the same rate. For example, a genomic island for Nif genes was identified in three of the five genomes with significantly elevated SNV counts. dN/dS analyses revealed evidence for frequency-dependent selection, in which genes unique to individual SAGs displayed elevated diversifying selection relative to other genes. These results indicate that different strains of Methanothermococcus outcompete others in specific environmental settings, and that these fitness advantages may result from variation in the pangenome, as revealed by dN/dS and SNV analyses. By examining variation and the scale of nucleotide and genes, we aim to gain insight into the roles of genetic diversity and environmental selection on microbial evolution in these ecosystems.

Influence of skin ageing features on Chinese women's perception of facial age and attractiveness.

PubMed

Porcheron, A; Latreille, J; Jdid, R; Tschachler, E; Morizot, F

2014-08-01

Ageing leads to characteristic changes in the appearance of facial skin. Among these changes, we can distinguish the skin topographic cues (skin sagging and wrinkles), the dark spots and the dark circles around the eyes. Although skin changes are similar in Caucasian and Chinese faces, the age of occurrence and the severity of age-related features differ between the two populations. Little is known about how the ageing of skin influences the perception of female faces in Chinese women. The aim of this study is to evaluate the contribution of the different age-related skin features to the perception of age and attractiveness in Chinese women. Facial images of Caucasian women and Chinese women in their 60s were manipulated separately to reduce the following skin features: (i) skin sagging and wrinkles, (ii) dark spots and (iii) dark circles. Finally, all signs were reduced simultaneously (iv). Female Chinese participants were asked to estimate the age difference between the modified and original images and evaluate the attractiveness of modified and original faces. Chinese women perceived the Chinese faces as younger after the manipulation of dark spots than after the reduction in wrinkles/sagging, whereas they perceived the Caucasian faces as the youngest after the manipulation of wrinkles/sagging. Interestingly, Chinese women evaluated faces with reduced dark spots as being the most attractive whatever the origin of the face. The manipulation of dark circles contributed to making Caucasian and Chinese faces being perceived younger and more attractive than the original faces, although the effect was less pronounced than for the two other types of manipulation. This is the first study to have examined the influence of various age-related skin features on the facial age and attractiveness perception of Chinese women. The results highlight different contributions of dark spots, sagging/wrinkles and dark circles to their perception of Chinese and Caucasian faces. © 2014 The Authors. International Journal of Cosmetic Science published by John Wiley & Sons Ltd on behalf of Society of Cosmetic Scientists and Societe Francaise de Cosmetologie.

A new low voltage level-shifted FVF current mirror with enhanced bandwidth and output resistance

NASA Astrophysics Data System (ADS)

Aggarwal, Bhawna; Gupta, Maneesha; Gupta, Anil Kumar; Sangal, Ankur

2016-10-01

This paper proposes a new high-performance level-shifted flipped voltage follower (LSFVF) based low-voltage current mirror (CM). The proposed CM utilises the low-supply voltage and low-input resistance characteristics of a flipped voltage follower (FVF) CM. In the proposed CM, level-shifting configuration is used to obtain a wide operating current range and resistive compensation technique is employed to increase the operating bandwidth. The peaking in frequency response is reduced by using an additional large MOSFET. Moreover, a very high output resistance (in GΩ range) along with low-current transfer error is achieved through super-cascode configuration for a wide current range (0-440 µA). Small signal analysis is carried out to show the improvements achieved at each step. The proposed CM is simulated by Mentor Graphics Eldospice in TSMC 0.18 µm CMOS, BSIM3 and Level 53 technology. In the proposed CM, a bandwidth of 6.1799 GHz, 1% settling time of 0.719 ns, input and output resistances of 21.43 Ω and 1.14 GΩ, respectively, are obtained with a single supply voltage of 1 V. The layout of the proposed CM has been designed and post-layout simulation results have been shown. The post-layout simulation results for Monte Carlo and temperature analysis have also been included to show the reliability of the CM against the variations in process parameters and temperature changes.

Limitations of threshold voltage engineering of AlGaN/GaN heterostructures by dielectric interface charge density and manipulation by oxygen plasma surface treatments

NASA Astrophysics Data System (ADS)

Lükens, G.; Yacoub, H.; Kalisch, H.; Vescan, A.

2016-05-01

The interface charge density between the gate dielectric and an AlGaN/GaN heterostructure has a significant impact on the absolute value and stability of the threshold voltage Vth of metal-insulator-semiconductor (MIS) heterostructure field effect transistor. It is shown that a dry-etching step (as typically necessary for normally off devices engineered by gate-recessing) before the Al2O3 gate dielectric deposition introduces a high positive interface charge density. Its origin is most likely donor-type trap states shifting Vth to large negative values, which is detrimental for normally off devices. We investigate the influence of oxygen plasma annealing techniques of the dry-etched AlGaN/GaN surface by capacitance-voltage measurements and demonstrate that the positive interface charge density can be effectively compensated. Furthermore, only a low Vth hysteresis is observable making this approach suitable for threshold voltage engineering. Analysis of the electrostatics in the investigated MIS structures reveals that the maximum Vth shift to positive voltages achievable is fundamentally limited by the onset of accumulation of holes at the dielectric/barrier interface. In the case of the Al2O3/Al0.26Ga0.74N/GaN material system, this maximum threshold voltage shift is limited to 2.3 V.

Power quality improvement by using STATCOM control scheme in wind energy generation interface to grid

NASA Astrophysics Data System (ADS)

Kirmani, Sheeraz; Kumar, Brijesh

2018-01-01

“Electric Power Quality (EPQ) is a term that refers to maintaining the near sinusoidal waveform of power distribution bus voltages and currents at rated magnitude and frequency”. Today customers are more aware of the seriousness that the power quality possesses, this prompt the utilities to assure good quality of power to their customer. The power quality is basically customer centric. Increased focus of utilities toward maintaining reliable power supply by employing power quality improvement tools has reduced the power outages and black out considerably. Good power quality is the characteristic of reliable power supply. Low power factor, harmonic pollution, load imbalance, fast voltage variations are some common parameters which are used to define the power quality. If the power quality issues are not checked i.e. the parameters that define power quality doesn't fall within the predefined standards than it will lead into high electricity bill, high running cost in industries, malfunctioning of equipments, challenges in connecting renewable. Capacitor banks, FACTS devices, harmonic filters, SVC’s (static voltage compensators), STATCOM (Static-Compensator) are the solutions to achieve the power quality. The performance of Wind turbine generators is affected by poor quality power, at the same time these wind power generating plant affects the power quality negatively. This paper presents the STATCOM-BESS (battery energy storage system) system and studies its impact on the power quality in a system which consists of wind turbine generator, non linear load, hysteresis controller for controlling the operation of STATCOM and grid. The model is simulated in the MATLAB/Simulink. This scheme mitigates the power quality issues, improves voltage profile and also reduces harmonic distortion of the waveforms. BESS level out the imbalances caused in real power due to intermittent nature of wind power available due to varying wind speeds.