These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Theory of high gain cavity-enhanced spontaneous parametric down-conversion  

E-print Network

We compute the output of multimode cavity-enhanced spontaneous parametric down-conversion (SPDC) for sub-threshold, but otherwise arbitrary, gain. We find analytic Bogoliubov transformations that allow us to calculate arbitrary field correlation functions, including the second-order intensity correlation function $G^{(2)}(T)$. The results show evidence of increased coherence due to stimulated SPDC. We extend an earlier model [Lu and Ou, Phys. Rev. A, 62, 033804 (2000)] to arbitrary gain and finesse, and show the extension gives accurate results in most scenarios. The results will allow simple, analytic description of cavity-based nonclassical light sources for quantum networking, quantum-enhanced sensing of atoms and generation of highly non-classical field states

Joanna A. Zieli?ska; Morgan W. Mitchell

2015-01-08

2

Theory of high gain cavity-enhanced spontaneous parametric down-conversion  

NASA Astrophysics Data System (ADS)

We compute the output of multimode cavity-enhanced spontaneous parametric down-conversion (SPDC) for subthreshold, but otherwise arbitrary, gain. We find analytic Bogoliubov transformations that allow us to calculate arbitrary field correlation functions, including the second-order intensity correlation function G(2 )(T ) . The results show evidence of increased coherence due to stimulated SPDC. We extend an earlier model [Lu and Ou, Phys. Rev. A 62, 033804 (2000), 10.1103/PhysRevA.62.033804] to arbitrary gain and finesse, and show the extension gives accurate results in most scenarios. The results will allow simple, analytic description of cavity-based nonclassical light sources for quantum networking, quantum-enhanced sensing of atoms, and generation of highly nonclassical field states.

Zieli?ska, Joanna A.; Mitchell, Morgan W.

2014-12-01

3

Spatially-selective amplified spontaneous emission (ASE) sources derived from a high-gain solid-state amplifier  

Microsoft Academic Search

We present high power amplified spontaneous emission sources with spatial selectivity, based on an ultra-high gain diode-pumped Nd:YVO4 crystal in a bounce amplifier geometry. Output power 30 W was achieved with near diffraction-limited spatial quality.

G. Smith; M. J. Damzen

2006-01-01

4

Gain media edge treatment to suppress amplified spontaneous emission in a high power laser  

DOEpatents

A novel method and apparatus for suppressing ASE and parasitic oscillation modes in a high average power laser is introduced. By roughening one or more peripheral edges of a solid-state crystal or ceramic laser gain media and by bonding such edges using a substantially high index bonding elastomer or epoxy to a predetermined electromagnetic absorbing arranged adjacent to the entire outer surface of the peripheral edges of the roughened laser gain media, ASE and parasitic oscillation modes can be effectively suppressed.

Hackel, Lloyd A. (Livermore, CA); Soules, Thomas F. (Livermore, CA); Fochs, Scott N. (Livermore, CA); Rotter, Mark D. (San Ramon, CA); Letts, Stephan A. (San Ramon, CA)

2008-12-09

5

Gain media edge treatment to suppress amplified spontaneous emission in a high power laser  

DOEpatents

A novel method and apparatus for suppressing ASE and/or parasitic oscillation modes in a laser is introduced. By roughening one or more peripheral edges of a solid-state crystal or ceramic laser gain media and by bonding such edges to a predetermined electromagnetic absorbing material arranged adjacent to the entire outer surface of the peripheral edges of the roughened laser gain media, ASE, parasitic oscillation modes and/or residual pump energy can be effectively suppressed.

Hackel, Lloyd A. (Livermore, CA); Soules, Thomas F. (Livermore, CA); Fochs, Scott N. (Livermore, CA); Rotter, Mark D. (San Ramon, CA); Letts, Stephan A. (San Ramon, CA)

2011-02-22

6

Spontaneous and stimulated Brillouin scattering gain spectra in optical fibers  

Microsoft Academic Search

We study the Brillouin scattering behavior in several single-mode fibers with different waveguide characteristics in terms of their longitudinal mode structures in the gain spectrum, linewidth narrowing, and stimulated Brillouin scattering (SBS) threshold levels. Evolution from spontaneous to SBS is investigated by monitoring the Brillouin line-shape and the behavior of the longitudinal acoustooptic resonance modes that exist in the core.

Aydin Yeniay; Jean-Marc Delavaux; Jean Toulouse

2002-01-01

7

Helicopter high gain control  

NASA Technical Reports Server (NTRS)

High gain control is explored through a design study of the CH-47B helicopter. The plans are designed to obtain the maximum bandwidth possible given the hardware constraints. Controls are designed with modal control theory to specific bandwidths and closed loop mode shapes. Comparisons are made to an earlier complementary filter approach. Bandwidth improvement by removal of limitations is explored in order to establish hardware and mechanization options. Improvements in the pitch axis control system and in the rate gyro sensor noise characteristics in all axes are discussed. The use of rotor state feedback is assessed.

Cunningham, T. B.; Nunn, E. C.

1979-01-01

8

Measurement of gain characteristics of semiconductor lasers by amplified spontaneous emissions from dual facets.  

PubMed

In this letter, we describe a novel gain measurement approach for semiconductor edge-emitting lasers, with which TE and TM gain spectra can be easily obtained by collecting the amplified spontaneous emissions at dual facets of the device. An unstrained and continuously-operated GaAs/AlGaAs single quantum well laser strip is used to illustrate this method. The measured gain spectra are compared with theoretical gain curves to analyze the gain polarization characteristics and the relevant subband structure in the valence band of the well using the measured gain spectra. PMID:23609743

Ma, M-L; Wu, J; Ning, Y-Q; Zhou, F; Yang, M; Zhang, X; Zhang, J; Shang, G-Y

2013-04-22

9

Planar High-Gain WLAN PCB Antenna  

Microsoft Academic Search

A simple design for a low-profile high-gain planar antenna has been presented in the letter. The antenna has the realized gain between 9 and 11 dBi and the return loss better than 10 dB over the 5.6-6.3-GHz frequency band, i.e. 11% bandwidth. A numerical study highlighting effects of key geometrical parameters on the gain and return loss of the antenna

Dmitry E. Zelenchuk; Vincent F. Fusco

2009-01-01

10

Quantum effects in high-gain free-electron lasers.  

PubMed

A many-particle fully quantized theory for a free-electron laser which is valid in the high-gain regime is presented. We examine quantum corrections for the high-gain single-pass free-electron laser. It is shown that quantum effects become significant when the photon energy becomes comparable to the gain bandwidth. The initiation of the free-electron laser process from quantum fluctuations in the position and momentum of the electrons is considered, and the parameter regime for enhanced start-up is identified. Photon statistics of the free-electron laser radiation are discussed, and the photon number statistics for the self-amplified spontaneous emission are calculated. PMID:11736108

Schroeder, C B; Pellegrini, C; Chen, P

2001-11-01

11

Spatially-selective amplified spontaneous emission source derived from an ultrahigh gain solid-state amplifier  

Microsoft Academic Search

An investigation is made into the performance of a high power solid-state amplified spontaneous emission (ASE) source with near-diffraction-limited beam quality. The radiation from this ASE source has high spatial quality and power, but unlike a laser it has a high misalignment tolerance and does not require a precisely aligned cavity. The source is based on a diode-pumped Nd:YVO4 laser

G. Smith; M. J. Damzen

2006-01-01

12

ASE suppression in high-gain solid-state amplifiers by a leak method  

NASA Astrophysics Data System (ADS)

A leak method was developed to suppress amplified spontaneous emission (ASE) in large-aperture high-gain solid-state amplifiers. The gain medium edges are processed into an arris. The ASE ray will undergo reflection several times at the arris surface when it propagates to the gain medium edges, and most of its power will leak out. This leak method was tested in an experiment, in which a piece of commonly used gain medium was processed for contrast. The maximal increase of the gain value was 5.26% with the maximal pump power.

Zhang, Yongliang; Ye, Haixian; Li, Mingzhong; Zheng, Jiangang; Wei, Xiaofeng; Gao, Song; Deng, Qinghua; Jiang, Xinying; Yan, Xiongwei; Wang, Zhenguo

2013-07-01

13

Mechanisms of the Rosetta high gain antenna  

Microsoft Academic Search

This paper describes the antenna pointing mechanism (APM) and the hold down and release mechanism (HRM) used in the high gain antenna of the ROSETTA mission. The hold down and release mechanism consists of three units which compensate the tolerance mismatch between antenna and spacecraft through incorporation of potting rings. Given that the activation mode is pyrotechnic, release shock is

Carlos Pereira

2001-01-01

14

High Gain Fast Ignition Point Design  

Microsoft Academic Search

The fast ignition (FI) approach to inertial confinement fusion offers the potential for achieving the high target gains required for Inertial Fusion Energy (IFE). In FI a D-T fuel capsule is first compressed via a quasi-isochoric implosion to form a high density core, and then ignited with a short-pulse laser-generated relativistic electron beam. This paper reports progress on the development

P. K. Patel; P. Amendt; C. D. Chen; D. Clark; B. Cohen; D. S. Hey; L. Divol; D. Higginson; D. Ho; D. Homoelle; A. J. Kemp; M. H. Key; D. Larson; B. Lasinski; S. Le Pape; T. Ma; H. McLean; D. J. Meeker; Y. Ping; H. Shay; D. J. Strozzi; M. Tabak; R. P. J. Town; B. Westover; S. C. Wilks

2010-01-01

15

Mechanisms of the Rosetta high gain antenna  

NASA Astrophysics Data System (ADS)

This paper describes the antenna pointing mechanism (APM) and the hold down and release mechanism (HRM) used in the high gain antenna of the ROSETTA mission. The hold down and release mechanism consists of three units which compensate the tolerance mismatch between antenna and spacecraft through incorporation of potting rings. Given that the activation mode is pyrotechnic, release shock is a major concern and is minimised through integration of shock absorbers which allow stroking of the separation nuts. The antenna pointing mechanism is a dual drive (azimuth over elevation) unit which allows controlled rotation of the antenna. The drive units incorporate spring loaded end stops to prevent the antenna from hitting the spacecraft, and optical encoders which register the absolute position of the antenna. The pointing and the hold down mechanisms of the ROSETTA antenna are fully qualified and will withstand the high launch loads of the Ariane-5 and the environmental demands of deep space operation.

Pereira, Carlos

2001-09-01

16

High Gain Fast Ignition Point Design  

NASA Astrophysics Data System (ADS)

The fast ignition (FI) approach to inertial confinement fusion offers the potential for achieving the high target gains required for Inertial Fusion Energy (IFE). In FI a D-T fuel capsule is first compressed via a quasi-isochoric implosion to form a high density core, and then ignited with a short-pulse laser-generated relativistic electron beam. This paper reports progress on the development of a point design for an indirect-drive re-entrant cone FI target. The design incorporates 2-D radiation-hydrodynamics modeling of the capsule implosion around a cone, particle-in-cell (PIC) modeling of the short-pulse laser absorption and electron generation at the cone tip, and hybrid-PIC modeling of the electron transport and heating in the compressed fuel. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Patel, P. K.; Amendt, P.; Chen, C. D.; Clark, D.; Cohen, B.; Hey, D. S.; Divol, L.; Higginson, D.; Ho, D.; Homoelle, D.; Kemp, A. J.; Key, M. H.; Larson, D.; Lasinski, B.; Le Pape, S.; Ma, T.; McLean, H.; Meeker, D. J.; Ping, Y.; Shay, H.; Strozzi, D. J.; Tabak, M.; Town, R. P. J.; Westover, B.; Wilks, S. C.

2010-11-01

17

High-power near-diffraction-limited solid-state amplified spontaneous emission laser devices  

Microsoft Academic Search

We present investigations into high-power scaling of solid-state amplified spontaneous emission (ASE) laser sources by use of two high-gain (˜104) Nd:YVO4 bounce amplifiers. The sources deliver high power with a high-quality spatial output, but unlike a laser they have a high misalignment tolerance and do not require a precisely aligned cavity. In one system with two amplifiers, we demonstrate an

G. Smith; P. C. Shardlow; M. J. Damzen

2007-01-01

18

A Gain-of-Function Mutation in a Cytokinin Receptor Triggers Spontaneous Root Nodule Organogenesis  

Microsoft Academic Search

Legume root nodules originate from differentiated cortical cells that reenter the cell cycle and form organ primordia. We show that perception of the phytohormone cytokinin is a key element in this switch. Mutation of a Lotus japonicus cytokinin receptor gene leads to spontaneous development of root nodules in the absence of rhizobia or rhizobial signal molecules. The mutant histidine kinase

Leïla Tirichine; Niels Sandal; Lene H. Madsen; Simona Radutoiu; Anita S. Albrektsen; Shusei Sato; Erika Asamizu; Satoshi Tabata; Jens Stougaard

2007-01-01

19

Development of high gain GEM detectors  

E-print Network

We describe systematic measurements carried out with single and double GEM detectors with printed circuit readout. The maximum safe operating gain has been measured at increasing radiation flux and under exposure to heavily ionizing tracks. Detection efficiency, localization accuracy and cluster size have been measured in a minimum ionizing particle beam. With a suitably configured readout electrode, fast, two-dimensional localization of radiation is demonstrated. (15 refs).

Bressan, A; Sauli, Fabio; Mörmann, D

2000-01-01

20

A simple model of gain saturation in high gain single pass free electron lasers  

Microsoft Academic Search

The saturation dynamics of a high gain single passage FEL is reproduced by means of an analytical model based on Bloch-type equations, similar to those governing the physics of conventional lasers. The main results of the paper is the proof that the evolution from small to strong signal regime can be described in terms of the logistic function, whose validity

G. Dattoli; L. Giannessi; P. L Ottaviani; M. Carpanese

1997-01-01

21

Cold test, spontaneous emission and gain in a rectangular Cerenkov amplifier  

SciTech Connect

The authors present experimental results for the rectangular Cerenkov grating amplifier. This research is being carried out to develop a Ka-band (35 GHz), low voltage (10 kV), moderate power (10 kW) source. They have constructed a Ku-band grating structure to study a scaled version of this source. The tapered grating consists of two tapered Ku-band smooth wave guide sections and two 3.5-inch sections of five-step-tapered gratings. Both tapered and untapered grating structures have been cold tested utilizing the network analyzer measurements. They find that their taper design reduced the reflection coefficient from {minus}5 dB to less than {minus}20 dB over a 12--15 GHz bandwidth. Spontaneous emission results resulting from passing the circular electron beam from a Litton thermionic gun over the grating structure will be presented. They have theoretically investigated the sheet beam interaction with hybrid modes in a deep groove rectangular grating waveguide. A complex dispersion relation, which includes a finite axial energy spread of the beam, describing the interaction has been solved. The authors find that the instability is always convective in the forward wave mode regime.

Scharer, J.E.; Joe, J.; Booske, J.H.; Basten, M.; Kirolous, H. [Univ. of Wisconsin, Madison, WI (United States). Electrical and Computer Engineering Dept.

1994-12-31

22

Computer simulation of space station computer steered high gain antenna  

NASA Technical Reports Server (NTRS)

The mathematical modeling and programming of a complete simulation program for a space station computer-steered high gain antenna are described. The program provides for reading input data cards, numerically integrating up to 50 first order differential equations, and monitoring up to 48 variables on printed output and on plots. The program system consists of a high gain antenna, an antenna gimbal control system, an on board computer, and the environment in which all are to operate.

Beach, S. W.

1973-01-01

23

Universal efficiency and gain computations for high-gain free-electron-laser amplifiers  

SciTech Connect

The free-electron-laser (FEL) equations are reduced to a set of one-dimensional, normalized equations that allow a universal (dimensional) analysis. In universal parameters, numerical integration of the FEL equations indicates a relatively constant saturated ponderomotive wave amplitude independent of both the normalized wiggler potential amplitude and the injected signal level. The constant ponderomotive wave amplitude and an empirical fit for the universal saturation length as a function of normalized wiggler potential amplitude and gain permits unnormalized design calculations for saturated power and saturated length over a wide parameter range. Tapering is considered by deriving analytical expressions for the intrinsic efficiency and taper length. Design values for a high-gain, high-efficiency, tapered amplifier at 280 and 560 GHz are presented.

Booske, J.H. (Department of Electrical and Computer Engineering, University of Wisconsin, Madison, Wisconsin 53706 (USA)); Bidwell, S.W.; Levush, B.; Antonsen, T.M. Jr.; Granatstein, V.L. (Laboratory for Plasma Research, University of Maryland, College Park, Maryland 20742 (USA))

1991-06-01

24

High gain amplifiers: Power oscillations and harmonic generation  

SciTech Connect

We discuss the power oscillations in saturated high gain free electron laser amplifiers and show that the relevant period can be written in terms of the gain length. We use simple arguments following from the solution of the pendulum equation in terms of Jacobi elliptic functions. Nontrivial effects due to nonlinear harmonic generation and inhomogeneous broadening are discussed too, as well as the saturated dynamics of short pulses.

Dattoli, G.; Ottaviani, P. L.; Pagnutti, S. [ENEA, Dipartimento Tecnologie Fisiche e Nuovi Materiali, Centro Ricerche Frascati, C.P. 65-00044 Frascati, Rome (Italy)

2007-08-01

25

High-gain GaAs MSM photodetector  

NASA Astrophysics Data System (ADS)

Photodetectors with metal-semiconductor -metal (MSM) structures having very high quan turn efficiency are investigated to identify the gain mechanism. From the temperature dependence studies impact ionisation of carriers in a region under the edge of the cathode is shown to be the predominant gain mechanism. Metal-Semiconductors-Metal (MSM) structure has recently emerged" 2 as an attractive device for photodetection due to its simple planar tech nology which can be easily adapted to optoelec tronic integration. The other features of MSM photodetector are their high sensitivity, low capacitance, low dark current and high speed. Substatial amount of work has been done on GaAs MSM photodiodes which are useful in near infrared wavelength regime. Devices with very low dark current (lOOpA at 1OV for 200x200pm geometry) and low rise and fall times (23 and 55 ps respecti vely) have been recently fabricated on semi-insu lating (SI) GaAs substrates1. The other interest ing feature of MSM structure is that it has in ternal gain. Despite intensive study of these devices there is still confusion about the physi cal origin of the gain in these devices. Ito et a13 attribute the gain to hole injection at the forward biased anode contact. Measurements of Zirngibl et al however, point to avalanche mechanism of gain in these devices. In this paper we report the results of experimental in vestigation of gain mechanism in GaAs MSM struc tures which have extremely high gain (100).

Karulkar, V. T.; Purandare, S. C.; Srivastava, Atul K.; Arora, B. M.

1992-12-01

26

2 to 8 GHz high gain monolithic feedback amplifier  

NASA Astrophysics Data System (ADS)

The design of a 2 to 8 GHz high-gain feedback monolithic amplifier chip (SA-0167) is described, together with FET processing and experimental results. The SA-0167 chip, which measures 0.12 in. x 0.08 in., provides a nominal gain of 12 dB with an output power level flatness of + or - 0.5 dB, and an input/output impedance mismatch of 2:1 maximum across the frequency band. The chip is a two-stage design using a small gate periphery FET (0.5 micron x 300 microns) for optimum small signal gain performance, moderate output power, and low current consumption. The circuit shows a high degree of insensitivity to processing variations, resulting in high uniform yield. Schematic diagram of the feedback amplifier is included.

Priolo, Martin; Barratt, Curtis; Onge, Gary S.

1989-08-01

27

Coherence properties of high-gain twin beams  

NASA Astrophysics Data System (ADS)

Twin-beam coherence properties are analyzed in both spatial and spectral domains at high gain, including also the regime of pump depletion. We show an increase in the size of the intensity autocorrelation and cross-correlation areas at increasing pump power, replaced by a decrease in the pump depletion regime. This effect is interpreted as a progressive loss in the mode selection occurring at high-gain amplification. The experimental determination of the number of spatiospectral modes from the measurements of the g(2 )-intensity autocorrelation coefficient confirms this explanation.

Allevi, A.; Jedrkiewicz, O.; Brambilla, E.; Gatti, A.; Pe?ina, J.; Haderka, O.; Bondani, M.

2014-12-01

28

Spontaneous activity, economy of activity, and resistance to diet-induced obesity in rats bred for high intrinsic aerobic capacity  

Microsoft Academic Search

Though obesity is common, some people remain resistant to weight gain even in an obesogenic environment. The propensity to remain lean may be partly associated with high endurance capacity along with high spontaneous physical activity and the energy expenditure of activity, called non-exercise activity thermogenesis (NEAT). Previous studies have shown that high-capacity running rats (HCR) are lean compared to low-capacity

Colleen M. Novak; Carlos Escande; Paul R. Burghardt; Minzhi Zhang; Maria Teresa Barbosa; Eduardo N. Chini; Steven L. Britton; Lauren G. Koch; Huda Akil; James A. Levine

2010-01-01

29

Transverse amplified spontaneous emission: The limiting factor for output energy of ultra-high power lasers  

NASA Astrophysics Data System (ADS)

For the new generation of the ultra-high power lasers with tens of PW of output power, kJ-level energies have to be reached. Our modeling, applied to Ti:sapphire amplifiers, demonstrates for the first time, according our knowledge, that Transverse Amplified Spontaneous Emission (TASE) places an additional restriction on storing and extracting energy in larger gain apertures, even stronger than transverse parasitic generation (TPG). Nevertheless, we demonstrate that extracting during pumping (EDP) can significantly reduce parasitic losses due to both TASE and TPG.

Chvykov, Vladimir; Nees, John; Krushelnick, Karl

2014-02-01

30

High-gain APD array for photon detection  

NASA Astrophysics Data System (ADS)

Arrays of high speed, high gain avalanche photodiodes (APDs) have been developed for use as high sensitivity optical photon detectors. The 1 mm2 area APD pixels yield a maximum avalanche gain of 40,000 and a high signal-to-noise ratio with only moderate cooling (-22 degrees to -43 degrees C). These devices demonstrate 70% detection efficiency for 6 photon optical pulses and 35% detection efficiency for 3 photon optical pulses. The rise time is less than 2 nsec, and the fall time less than 7 nsec. Pixellating the PAD into a monolithic array will significantly reduce the cost per pixel compared to discrete devices. These devices will have great utility in various applications, ranging from high energy physics to biological instrumentation. The measured performance of these APD arrays as optical detectors will be discussed.

Farrell, Richard; Redus, Robert H.; Gordon, Jeffrey S.; Gothoskar, Prakash

1995-09-01

31

High gain 1310nm Raman amplifier (withdrawal notice)  

NASA Astrophysics Data System (ADS)

This paper has been withdrawn. The following nearly identical paper is available in this conference proceedings: Jaros?aw Piotr Turkiewicz and Pawe? Czy?ak, "The high gain 1310nm Raman amplifier," Proc. SPIE 9228, Optical Fibers and Their Applications 2014, 92280P (May 12, 2014); doi:10.1117/12.2067055.

Czy?ak, Pawe?; Turkiewicz, Jaros?aw Piotr; Mazurek, Pawe?

2014-05-01

32

Topex high-gain antenna system deployment actuator mechanism  

NASA Technical Reports Server (NTRS)

A deployment actuator mechanism was developed to drive a two-axis gimbal assembly and a high-gain antenna to a deployed and locked position on the Jet Propulsion Laboratory Ocean Topography Experiment (TOPEX) satellite. The Deployment Actuator Mechanism requirements, design, test, and associated problems and their solutions are discussed.

Jones, Stephen R.

1991-01-01

33

Dispersion relations for 1D high-gain FELs  

SciTech Connect

We present analytical results for the one-dimensional dispersion relation for high-gain FELs. Using kappa-n distributions, we obtain analytical relations between the dispersion relations for various order kappa distributions. Since an exact solution exists for the kappa-1 (Lorentzian) distribution, this provides some insight into the number of modes on the way to the Gaussian distribution.

Webb, S.D.; Litvinenko, V.N.

2010-08-23

34

A hybrid nanoantenna for highly enhanced directional spontaneous emission  

SciTech Connect

Spontaneous emission modulated by a hybrid plasmonic nanoantenna has been investigated by employing finite-difference time-domain method. The hybrid nanoantenna configurations constituted by a gap hot-spot and of a plasmonic corrugated grating and a metal reflector sandwiching a SiO{sub 2} thin layer which appears promising for high spontaneous emission enhancement devices. Simulation assays show that the coupling between the gap-antenna and plasmonic corrugations reaches an ultra-high near-field enhancement factor in the excitation process. Moreover, concerning the emission process, the corrugations concentrate the far-field radiated power within a tiny angular volume, offering unprecedented collection efficiency. In the past decades, many kinds of optical antennas have been proposed and optimized to enhance single molecule detection. However, the excitation enhancement effect for single individual or dimmer plasmonic nanostructure is limited due to intrinsic nonradiative decay of the nanoparticle plasmon and quantum tunneling effect. The proposed hybrid configuration overwhelms the enhancement limit of single individual plasmonic structure. The findings provide an insight into spontaneous emission high enhancement through integrating the functions of different metallic nanostructures.

Chou, R. Yuanying; Lu, Guowei, E-mail: guowei.lu@pku.edu.cn; Shen, Hongming; He, Yingbo; Cheng, Yuqing [State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing 100871 (China); Perriat, Pascal [MATEIS, UMR 5510 CNRS, INSA-Lyon, Université de Lyon, Villeurbanne Cedex 69621 (France); Martini, Matteo; Tillement, Olivier [ILM, UMR 5306 CNRS, Université de Lyon, Villeurbanne Cedex 69622 (France); Gong, Qihuang [State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing 100871 (China); Collaborative Innovation Center of Quantum Matter, Beijing 100871 (China)

2014-06-28

35

High resolution BPMS with integrated gain correction system  

SciTech Connect

High resolution beam position monitors (BPM) are an essential tool to achieve and reproduce a low vertical beam emittance at the KEK Accelerator Test Facility (ATF) damping ring. The ATF damping ring (DR) BPMs are currently upgraded with new high resolution read-out electronics. Based on analog and digital down-conversion techniques, the upgrade includes an automatic gain calibration system to correct for slow drift effects and ensure high reproducible beam position readings. The concept and its technical realization, as well as preliminary results of beam studies are presented.

Wendt, M.; Briegel, C.; Eddy, N.; Fellenz, B.; Gianfelice, E.; Prieto, P.; Rechenmacher, R.; Voy, D.; /Fermilab; Terunuma, N.; Urakawa, J.; /KEK, Tsukuba

2009-08-01

36

Remote Robot Control With High Force-Feedback Gain  

NASA Technical Reports Server (NTRS)

Improved scheme for force-reflecting hand control of remote robotic manipulator provides unprecedently high force-reflection gain, even when dissimilar master and slave arms used. Three feedback loops contained in remote robot control system exerting position-error-based force feedback and compliance control. Outputs of force and torque sensors on robot not used directly for force reflection, but for compliance control, while errors in position used to generate reflected forces.

Kim, Won S.

1993-01-01

37

L-band automatic-gain-controlled erbium-doped fiber amplifier utilizing C-band backward-amplified spontaneous emission and electrical feedback monitor.  

PubMed

A new L-band automatic-gain-controlled (AGC) erbium-doped fiber amplifier (EDFA) for dense wavelength-division-multiplexing transmission systems is presented, in which a single 1480 nm laser with an internal thermoelectric cooler is used as a primary pump for stable amplification. All C-band amplified spontaneous emission (ASE) is recycled by the secondary pump to enhance the gain efficiency. A fraction of the output signal is used as an electrical feedback monitor for the AGC to improve the gain-clamped (GC) flatness. Experimental results prove that the AGC EDFA has a gain flatness of better than 0.46 dB/40 nm, i.e., below 1.5%, and a higher gain of approximately 36.5 dB compared to that of approximately 35.3 dB for the conventional GC EDFA at -30 dBm input signal power. The best gain flatness of +/-0.25 dB can be achieved over the dynamic range greater than 20 dB. The dynamic range of noise figure is between 6.7 and 7.1. The 3 dB down bandwidth is more than 40 nm. Overall dynamics measurements for the AGC EDFA feedback stabilization have been carried out. The recorded corresponding rise time of 1.565 ms indicates that the system does not exhibit any overshoot of gain or ASE variation due to the signal at the beginning of the pulse. PMID:19209194

Shen, Jyi-Lai; Lee, Yueh-Chien; Huang, Chia-Chih

2009-02-10

38

A high gain antenna system for airborne satellite communication applications  

NASA Technical Reports Server (NTRS)

A high gain antenna for commercial aviation satellites communication is discussed. Electromagnetic and practical design considerations as well as candidate systems implementation are presented. An evaluation of these implementation schemes is given, resulting in the selection of a simple top mounted aerodynamic phased array antenna with a remotely located beam steering unit. This concept has been developed into a popular product known as the Canadian Marconi Company CMA-2100. A description of the technical details is followed by a summary of results from the first production antennas.

Maritan, M.; Borgford, M.

1990-01-01

39

56.6 DB High Gain L-Band Edfa Utilizing Short-Length Highly-Doped Erbium Rare-Earth Material  

NASA Astrophysics Data System (ADS)

In this paper, we experimentally investigate the performance of an efficient high gain L-band erbium-doped fiber (EDF) amplifier structure utilizing short-length highly-doped erbium rare-earth material with a single pump source. The amplifier gain and noise figure variation for different amplifier structures have been investigated. A filter is used to reduce the self-saturation effect and suppress the C-band amplified spontaneous emission (ASE) noise. The amplifier achieves a signal gain of 56.6 dB with a low noise figure of 4.8 dB at -50 dBm input signal power using only 8 m of EDF length. The amplifier gain shows significant improvement of 6 dB with C/L band coupler and 13 dB with tunable-band pass filter compared to amplifier structure without ASE suppression.

Al-Mansoori, M. H.; Al-Ghaithi, W. S.

2014-07-01

40

Spontaneous Raman scattering as a high resolution XUV radiation source  

NASA Technical Reports Server (NTRS)

A type of high resolution XUV radiation source is described which is based upon spontaneous anti-Stokes scattering of tunable incident laser radiation from atoms excited to metastable levels. The theory of the source is summarized and two sets of experiments using He (1s2s)(1)S atoms, produced in a cw hollow cathode and in a pulsed high power microwave discharge, are discussed. The radiation source is used to examine transitions originating from the 3p(6) shell of potassium. The observed features include four previously unreported absorption lines and several sharp interferences of closely spaced autoionizing lines. A source linewidth of about 1.9 cm(-1) at 185,000 cm(-1) is demonstrated.

Rothenberg, J. E.; Young, J. F.; Harris, S. E.

1983-01-01

41

Spontaneous Raman Scattering Diagnostics for High-pressure Gaseous Flames  

NASA Technical Reports Server (NTRS)

A high-pressure (up to 60 atm) gaseous burner facility with optical access that provides steady, reproducible flames with high precision, and the ability to use multiple fuel/oxidizer combinations has been developed. In addition, a high-performance spontaneous Raman scattering system for use in the above facility has also been developed. Together, the two systems will be used to acquire and establish a comprehensive Raman scattering spectral database for use as a quantitative high-pressure calibration of single-shot Raman scattering measurements in high-pressure combustion systems. Using these facilities, the Raman spectra of H2-Air flames were successfully measured at pressures up to 20 atm. The spectra demonstrated clear rotational and ro-vibrational Raman features of H2, N2, and H2O. theoretical Raman spectra of pure rotational H2, vibrational H2, and vibrational N2 were calculated using a classical harmonic-oscillator model with pressure broadening effects and fitted to the data. At a gas temperature of 1889 K for a phi = 1.34 H2-Air flame, the model and the data showed good agreement, confirming a ro-vibrational equilibrium temperature.

Kojima, Jun; Nguyen, Quang-Viet; Reddy, D. R. (Technical Monitor)

2002-01-01

42

High gain GaAs photoconductive semiconductor switches: Switch longevity  

SciTech Connect

Optically activated, high gain GaAs switches are being tested for many different pulsed power applications that require long lifetime (longevity). The switches have p and n contact metallization (with intentional or unintentional dopants) configured in such a way as to produce p-i-n or n-i-n switches. The longevity of the switches is determined by circuit parameters and by the ability of the contacts to resist erosion. This paper will describe how the switches performed in test-beds designed to measure switch longevity. The best longevity was achieved with switches made with diffused contacts, achieving over 50 million pulses at 10 A and over 2 million pulses at 80 A.

Loubriel, G.M.; Zutavern, F.J.; Mar, A. [and others

1998-07-01

43

High-Gain Avalanche Rushing amorphous Photoconductor (HARP) detector  

NASA Astrophysics Data System (ADS)

We have been studying a very sensitive image sensor since the early 1980s. In 1985, the author found for the first time that an experimental pickup tube with an amorphous selenium photoconductive target exhibits high sensitivity with excellent picture quality because of a continuous and stable avalanche multiplication phenomenon. We named the pickup tube with an amorphous photoconductive layer operating in the avalanche-mode "HARP": High-gain Avalanche Rushing amorphous Photoconductor. A color camera equipped with the HARP pickup tubes has a maximum sensitivity of 11 lx at F8. This means that the HARP camera is about 100 times as sensitive as that of CCD camera for broadcasting. This ultrahigh-sensitivity HARP pickup tube is a powerful tool for reporting breaking news at night and other low-light conditions, the production of scientific programs, and numerous other applications, including medical diagnoses, biotech research, and nighttime surveillance. In addition, since the HARP target can convert X-rays into electrons directly, it should be possible to exploit this capability to produce X-ray imaging devices with unparalleled levels of resolution and sensitivity.

Tanioka, K.

2009-09-01

44

High fertility does not cause spontaneous intrauterine fetal loss: the determinants of spontaneous fetal loss in Egypt.  

PubMed

This study is concerned with a major, though relatively neglected, reproductive health issue: fetal loss. In particular, the determinants of spontaneous intrauterine mortality in Egypt are investigated with stress on the demographic determinants. To this end, a conceptual framework is developed. Using pregnancy history data from a national survey conducted in Egypt in 1995, the determinants of spontaneous intrauterine fetal deaths among currently married women aged 18-45 are examined using multiple logistic models. It is found that the probability of intrauterine fetal loss rises with maternal age. The apparent positive association of the risk with gravidity is shown to be an artifact, due to the heterogeneity among women with respect to the risk of pregnancy loss, the consequent selection process, and reproductive compensation behavior according to the "success/failure" stopping rule. Therefore, high fertility cannot be said to cause spontaneous fetal loss. Two other features of a woman's reproduction are of strong significance, namely, her pregnancy history and spacing among pregnancies. Once a woman suffers from spontaneous fetal loss, the probability of undergoing further pregnancy losses rises sharply. And the shorter the pregnancy interval, the higher the probability of pregnancy loss. Pregnancies conceived after long intervals are less likely to end in loss. PMID:12055696

el-Saadani, S

2000-01-01

45

Solar Dynamics Observatory High Gain Antenna Handover Planning  

NASA Technical Reports Server (NTRS)

The Solar Dynamics Observatory (SDO) is planned to launch in early 2009 as a mission to study the solar variability and its impact on Earth. To best satisfy its science goal, SDO will fly in a geosynchronous orbit with an inclination of approximately 29 deg. The spacecraft attitude is designed so that the science instruments point directly at the Sun with high accuracy. One of SDO's principal requirements is to obtain long periods of uninterrupted observations. The observations have an extremely high data volume so SDO must be in continuous contact with the ground during the observation periods. To maintain this contact, SDO is equipped with a pair of high gain antennas (HGAs) transmitting to a pair of ground antennas at the SDO ground station (SDOGS) located in White Sands, New Mexico. Either HGA can transmit to either SDOGS antenna. Neither HGA can be powered down. During a portion of each year, each of the HGA beams will intersect with the SDO body for a portion of the orbit. The original SDO antenna contact plan used each HGA for the half of each year during which its beam would not intersect the spacecraft. No data would be lost except, possibly, when switching from one antenna to another. After this plan was adopted, further analysis showed that daily handovers would be necessary for significant periods of the year. This unexpected need for extensive handovers necessitated that a handover design be developed to minimize the impact on the mission. This antenna handover design was developed and successfully tested with simulated data using the slew rate limits from preliminary jitter analysis. Subsequent analysis provided significant revision of allowed rates requiring modification of the handover plans.

Hashmall, Joseph A.; Mann, Laurie

2007-01-01

46

Characterization of nonlinear gain parameters in VECSELs to optimize femtosecond high average power operation  

NASA Astrophysics Data System (ADS)

Our femtosecond VECSELs have generated 1.05 W average output power. Numerical simulations have been successfully used to gain a better understanding, but initially have not predicted the average output power correctly. Only after we directly determined the correct gain parameters we got very good agreement. Numerical simulations show that weak gain saturation is beneficial for high-power operation. With a high-precision reflectivity measurement setup we measured the nonlinear change in reflectivity of the optically-pumped (OP) VECSEL gain chip as function of the incident pulse fluence, pump intensity, and heat-sink temperature. We also determined the small signal gain and the gain bandwidth.

Mangold, M.; Wittwer, V. J.; Sieber, O. D.; Hoffmann, M.; Golling, M.; Südmeyer, T.; Keller, U.

2013-02-01

47

Mechanisms underlying obesity resistance associated with high spontaneous physical activity  

PubMed Central

Obesity resistance due to elevated orexin signaling is accompanied by high levels of spontaneous physical activity (SPA). The behavioral and neural mechanisms underlying this observation have not been fully worked out. We determined the contribution of hypothalamic orexin receptors (OXR) to SPA stimulated by orexin A (OXA), whether OXA-stimulated SPA was secondary to arousal and whether voluntary wheel running led to compensations in 24-h SPA. We further tested whether orexin action on dopamine one receptors (DA1R) in the substantia nigra (SN) plays an important role in generation of SPA. To test this, SPA response was determined in lean and obese rats with cannulae targeted towards the rostral lateral hypothalamus (rLH) or SN. Sleep/wake states were also measured in rats with rLH cannula and EEG/EMG radiotelemetry transmitters. SPA in lean rats was more sensitive to antagonism of the orexin 1 receptor (OX1R) and in the early response to the orexin 2 agonist. OXA increased arousal equally in lean and obese rodents, which is discordant from the greater SPA response in lean rats. Obesity resistant rats ran more and wheel running was directly related to 24-h SPA levels. The OX1R antagonist, SB-334867-A, and the DA1R antagonist, SCH3390, in SN more effectively reduced SPA stimulated by OXA in OR rats. These data suggest OXA-stimulated SPA is not secondary to enhanced arousal, propensity for SPA parallels inclination to run and that orexin action on dopaminergic neurons in SN may participate in mediation of SPA and running wheel activity. PMID:24161277

Teske, Jennifer A.; Billington, Charles J.; Kotz, Catherine M.

2013-01-01

48

A very high frequency CMOS Variable Gain Amplifier  

E-print Network

-tuning by changing the analog control voltage of the multiplier, and 36dB digital coarse-tuning by switching and bypassing the current gain stage. Frequency compensation scheme based on capacitive feed-forward technique further improves the VGA bandwidth. The design...

Tan, Siang Tong

2012-06-07

49

Observation of high laser gain at 703 nm in a new chemical system  

Microsoft Academic Search

Results are presented on gain measurements in a new chemical laser system demonstrating positive gain in the visible spectral region. It is shown that visible stimulated emission is due to a metastable O4 complex produced in a sequence of reactions generally employed in a high power iodine laser (COIL). A maximum positive gain of 2.8 percent was measured at 703

Sanichiro Yoshida; Manabu Taniwaki; Tatsuo Sawano; Kouki Shimizu; Tomoo Fujioka

1989-01-01

50

Second-harmonic reflector type high-gain FET frequency doubler operating in K-band  

Microsoft Academic Search

A high-gain FET frequency doubler with a second-harmonic reflector in the input circuit has been developed. The reflector position which gives maximum multiplication gain depends on line loss. The relation between multiplication gain and the reflector position varies with line loss. A K-band frequency doubler designed on this basis was fabricated, showing a multiplication gain of 6 dB

Y. Iyama; A. Iida; T. Takagi; S. Urasaki

1989-01-01

51

Double-pass high-gain low-noise EDFA over S- and C+L-bands by tunable fundamental-mode leakage loss.  

PubMed

We demonstrate a high-gain low-noise double-pass tunable EDFA over S- and C+L-bands by discretely introducing fundamental-mode leakage loss in a 16-m-long standard C-band Er(3+)-doped fiber. The amplified spontaneous emission at the wavelengths of longer than 1530 nm can be substantially attenuated by the ASE suppressing filters to maintain high population inversion and to squeeze out the optical gain for S-band signals. When the filters are disabled, the gain bandwidth immediately returns back to the C+L-bands. Under S-band operation, a 37 dB small signal gain and a minimum 4.84 dB noise figure at 1486.9 nm are achieved with a 980 nm pump power of 154 mW. PMID:19532376

Hung, Chi-Ming; Chen, Nan-Kuang; Lai, Yinchieh; Chi, Sien

2007-02-19

52

Microsecond gain-switched master oscillator power amplifier (1958 nm) with high pulse energy  

NASA Astrophysics Data System (ADS)

An all-fibre master oscillator power amplifier (MOPA) emitting high-energy pulses at 1958 nm is presented. The seed laser is a microsecond gain-switched thulium-doped fibre laser (TDFL) pumped with a commercial 1550-nm pulsed fibre laser. The TDFL operates at a repetition rate f in the range of 10 to 100 kHz. The two-stage thulium-doped fibre amplifier is built to scale the energy of the pulses generated by the seed laser. The maximum output pulse energy higher than 0.5 mJ at 10 kHz is achieved which is comparable with the theoretical maximum extractable pulse energy. The slope efficiency of the second stage amplifier with respect to the pump power is 30.4% at f = 10 kHz. The wavelength of the output pulse laser is centred near 1958 nm at a spectral width of 0.25 nm after amplification. Neither nonlinear effects nor significant amplified spontaneous emission (ASE) is observed in the amplification experiments.

Yin, Ke; Yang, Weiqiang; Zhang, Bin; Li, Ying; Hou, Jing

2014-02-01

53

A Low-Profile Compact Microwave Antenna with High Gain  

Microsoft Academic Search

We demonstrate a novel, low-profile, compact antenna consisting of a rectangular dielectric resonator and a quasi-planar surface mounted horn. The proposed structure shows a gain of 8.5 dBi at 6.0 GHz, giving a 4.9 dB increase compared to the standard dielectric-resonator antenna (DRA) without a surface mounted horn. Total height of the fabricated structure is only 0.172 lambda0, or 8.61

Nasimuddin; K. P. Esselle; A. R. Weily; A. K. Verma

2005-01-01

54

NUTRIENT REQUIREMENTS OF HIGH-LEAN GAIN SWINE AT A HIGH ENVIRONMENTAL TEMPERATURE  

Technology Transfer Automated Retrieval System (TEKTRAN)

High-lean gain swine initially averaging 85 kg were assigned to 96 individual pens and given one of six diets ranging in the ratio of Total Ileal Digestible (TID) Lysine:Metabolizable Energy (ME) of 1.23 to 2.28 g/MCal. Pigs and feed intake were weighed weekly and backfat was measured on two week i...

55

Gain saturation effects in high-speed, multichannel erbium-doped fiber amplifiers at ?=1.53 ?m  

Microsoft Academic Search

Gain compression effects during multichannel signal amplification in an erbium-doped fiber amplifier at ?=1.53 are investigated. A theory is presented that accurately models the observed amplified spontaneous emission spectra, signal gains, and saturation effects. Measurements of the gain dynamics show recovery times in the 1-ms range, indicating that the fiber amplifier is immune to interchannel interference over a wide range

EMMANUEL DESURVIRE; C. RANDY GILES; JAY R. SIMPSON

1989-01-01

56

Achieving high gain and large bandwidth using hybrid DR antennas to feed short horns  

Microsoft Academic Search

Most high-gain antennas are narrow band and most wideband antennas have low gains. In this paper we present a low-profile antenna with a large impedance bandwidth, and high gain over the large impedance bandwidth. This is achieved by integrating a wideband hybrid DR on patch (DRoP) with a surface-mounted short horn (SMSH). Performance of antennas with two types of DRoP

Nasimuddin; K. Esselle

2007-01-01

57

Statistical theory of high-gain free-electron laser saturation Julien Barr,1,2,  

E-print Network

Statistical theory of high-gain free-electron laser saturation Julien Barré,1,2, * Thierry Dauxois, to predict the saturated state of a single-pass, high-gain free-electron laser. In analogy with the violent of generating coherent and tunable radiation sources, such as free-electron lasers (FELs). In this case

Dauxois, Thierry

58

High gain feedback control of direct-drive motor system by a homogeneous ER fluid  

Microsoft Academic Search

Because a direct-drive (DD) motor system does not use a reduction gear unit, the drive system can be made constructively simple and stiff. However, the disturbance torque directly influences the motor shaft. High gain feedback control is effective for reducing the influence of the disturbance torque. The high servo gain makes the control system vibratory or unstable. Therefore, the servo

K. Koyanagi; Naoyuki TAKESUE; G. Zhang; M. Sakaguchi; J. Furusho

2000-01-01

59

A High Dose Intravenous Immunoglobulin Therapy for Women with Four or More Recurrent Spontaneous Abortions  

PubMed Central

Recurrent spontaneous abortion (RSA) may have immunological etiology. The aim of this study was to assess the efficacy of a high dose intravenous immunoglobulin (HIVIg) therapy, in which 20?g of intact type immunoglobulin was infused daily for 5 days during early gestation, for women who had a history of four or more consecutive spontaneous abortions of unexplained etiology. A total of 60 pregnant RSA women underwent HIVIg therapy, and the pregnancy outcome was assessed. The live birth rate was 73.3% (44/60). Fifteen pregnancies ended in spontaneous abortion, and one ended in intrauterine fetal death. In 11 of the 15 spontaneous abortions, fetuses had abnormal chromosome karyotype. When the 11 pregnancies with abnormal chromosome karyotype were excluded, the live birth rate was as high as 89.8% (44/49). The HIVIg therapy may be effective for severe cases of unexplained RSA. PMID:22997588

Yamada, Hideto; Takeda, Masamitsu; Maezawa, Yoko; Ebina, Yasuhiko; Hazama, Ryoichi; Tanimura, Kenji; Wakui, Yukio; Shimada, Shigeki

2012-01-01

60

In-circuit-measurement of parasitic elements in high gain high bandwidth low noise transimpedance amplifiers.  

PubMed

Parasitic elements play an important role in the development of every high performance circuit. In the case of high gain, high bandwidth transimpedance amplifiers, the most important parasitic elements are parasitic capacitances at the input and in the feedback path, which significantly influence the stability, the frequency response, and the noise of the amplifier. As these parasitic capacitances range from a few picofarads down to only a few femtofarads, it is nearly impossible to measure them accurately using traditional LCR meters. Unfortunately, they also cannot be easily determined from the transfer function of the transimpedance amplifier, as it contains several overlapping effects and its measurement is only possible when the circuit is already stable. Therefore, we developed an in-circuit measurement method utilizing minimal modifications to the input stage in order to measure its parasitic capacitances directly and with unconditional stability. Furthermore, using the data acquired with this measurement technique, we both proposed a model for the complicated frequency response of high value thick film resistors as they are used in high gain transimpedance amplifiers and optimized our transimpedance amplifier design. PMID:25554310

Cochems, P; Kirk, A; Zimmermann, S

2014-12-01

61

In-circuit-measurement of parasitic elements in high gain high bandwidth low noise transimpedance amplifiers  

NASA Astrophysics Data System (ADS)

Parasitic elements play an important role in the development of every high performance circuit. In the case of high gain, high bandwidth transimpedance amplifiers, the most important parasitic elements are parasitic capacitances at the input and in the feedback path, which significantly influence the stability, the frequency response, and the noise of the amplifier. As these parasitic capacitances range from a few picofarads down to only a few femtofarads, it is nearly impossible to measure them accurately using traditional LCR meters. Unfortunately, they also cannot be easily determined from the transfer function of the transimpedance amplifier, as it contains several overlapping effects and its measurement is only possible when the circuit is already stable. Therefore, we developed an in-circuit measurement method utilizing minimal modifications to the input stage in order to measure its parasitic capacitances directly and with unconditional stability. Furthermore, using the data acquired with this measurement technique, we both proposed a model for the complicated frequency response of high value thick film resistors as they are used in high gain transimpedance amplifiers and optimized our transimpedance amplifier design.

Cochems, P.; Kirk, A.; Zimmermann, S.

2014-12-01

62

High gain photoconductive semiconductor switch having tailored doping profile zones  

Microsoft Academic Search

A photoconductive semiconductor switch with tailored doping profile zones beneath and extending laterally from the electrical contacts to the device. The zones are of sufficient depth and lateral extent to isolate the contacts from damage caused by the high current filaments that are created in the device when it is turned on. The zones may be formed by etching depressions

Albert G. Baca; Guillermo M. Loubriel; Alan Mar; Fred J Zutavern; Harold P. Hjalmarson; Andrew A. Allerman; Thomas E. Zipperian; Martin W. OMalley; Wesley D. Helgeson; Gary J. Denison; Darwin J. Brown; Charles T. Sullivan; Hong Q. Hou

2001-01-01

63

Design, development and testing of the x-ray timing explorer High Gain Antenna System  

NASA Technical Reports Server (NTRS)

The High Gain Antenna System (HGAS), consisting of two High Gain Antenna Deployment Systems (HGADS) and two Antenna Pointing Systems (APS), is used to position two High Gain Antennas (HGA) on the X-Ray Timing Explorer (XTE). A similar APS will be used on the upcoming Tropical Rainfall Measuring Mission (TRMM). Both XTE and TRMM are NASA in-house satellites. The salient features of the system include the two-axis gimbal and control electronics of the APS and the spring deployment and latch/release mechanisms of the HGADS. This paper describes some of the challenges faced in the design and testing of this system and their resolutions.

Lecha, Javier; Woods, Claudia; Phan, Minh

1995-01-01

64

High Gain Antenna Gimbal for the 2003-2004 Mars Exploration Rover Program  

NASA Technical Reports Server (NTRS)

The High Gain Antenna Assemblies built for the 2003-2004 Mars Exploration Rover (MER) missions provide the primary communication link for the Rovers once they arrive on Mars. The High Gain Antenna Gimbal (HGAG) portion of the assembly is a two-axis gimbal that provides the structural support, pointing, and tracking for the High Gain Antenna (HGA). The MER mission requirements provided some unique design challenges for the HGAG. This paper describes all the major subsystems of the HGAG that were developed to meet these challenges, and the requirements that drove their design.

Sokol, Jeff; Krishnan, Satish; Ayari, Laoucet

2004-01-01

65

High fertility does not cause spontaneous intrauterine fetal loss: The determinants of spontaneous fetal loss in Egypt  

Microsoft Academic Search

This study is concerned with a major, though relatively neglected, reproductive health issue: fetal loss. In particular, the determinants of spontaneous intrauterine mortality in Egypt are investigated with stress on the demographic determinants. To this end, a conceptual framework is developed. Using pregnancy history data from a national survey conducted in Egypt in 1995, the determinants of spontaneous intrauterine fetal

2000-01-01

66

High-Gain Top-Illuminated Optoelectronic Integrated Receiver  

Microsoft Academic Search

We present a monolithic photo-receiver based upon the InP\\/GalnAs HBT technology for optical communication at 1.55 mum. The photoreceiver consists of a top-illuminated photodiode and a transimpedance traveling wave amplifier. The same layers are used for the diodes and the base collector junction of the transistors. An advanced amplifier design, that achieves high bandwidth-to-fT ratio, expands the frequency response of

S. Kraus; D. Cohen-Elias; S. Cohen; A. Gavrilov; O. Kami; Y. Swirski; G. Eisenstein; D. Ritter

2007-01-01

67

High Gain Transformerless DC-DC Converters for Renewable Energy Sources  

E-print Network

Renewable energy sources including photovoltaic cells, fuel cells, and wind turbines require converters with high voltage gain in order to interface with power transmission and distribution networks. These conversions are conventionally made using...

Denniston, Nicholas Aaron

2011-08-08

68

75 FR 61228 - Board Meeting: Technical Lessons Gained From High-Level Nuclear Waste Disposal Efforts  

Federal Register 2010, 2011, 2012, 2013

...NUCLEAR WASTE TECHNICAL REVIEW BOARD Board Meeting: Technical Lessons Gained From High-Level Nuclear Waste Disposal Efforts Pursuant to its authority under section 5051 of Public Law 100-203, Nuclear Waste Policy Amendments...

2010-10-04

69

High-precision atom localization via controllable spontaneous emission in a cycle-configuration atomic system.  

PubMed

A scheme for realizing two-dimensional (2D) atom localization is proposed based on controllable spontaneous emission in a coherently driven cycle-configuration atomic system. As the spatial-position-dependent atom-field interaction, the frequency of the spontaneously emitted photon carries the information about the position of the atom. Therefore, by detecting the emitted photon one could obtain the position information available, and then we demonstrate high-precision and high-resolution 2D atom localization induced by the quantum interference between the multiple spontaneous decay channels. Moreover, we can achieve 100% probability of finding the atom at an expected position by choosing appropriate system parameters under certain conditions. PMID:22453461

Ding, Chunling; Li, Jiahua; Yu, Rong; Hao, Xiangying; Wu, Ying

2012-03-26

70

Active Flutter Suppression of a High-Aspect-Ratio Aeroelastic Using Gain Scheduling  

NASA Astrophysics Data System (ADS)

This paper presents a control design of gain scheduling controllers for active flutter suppression (AFS) in which the closed loop system is stabilized in the operating region specified in advance. The AFS system of a high-aspect-ratio wing is represented by a linearly interpolated polytopic model whose varying parameter is the dynamic pressure. The gain scheduling controller in this paper consists of a regulator and a full-order observer which are scheduled by the varying parameter. Linear matrix inequalities for designing the gains of the regulator and the observer are separately derived in the frame of the H2 optimization. The control performance and the characteristics of the designed gain scheduling controllers are evaluated in comparison with fixed H2 controllers which are designed with the same design parameters. As the result, the gain scheduling controllers may be inferior to the fixed controller at local regions, but are superior to the fixed controllers for the entire operating region.

Fujimori, Atsushi; Miura, Kyohei; Matsushita, Akira

71

High-gain weakly nonlinear flux-modulated Josephson parametric amplifier using a SQUID array  

NASA Astrophysics Data System (ADS)

We have developed and measured a high-gain quantum-limited microwave parametric amplifier based on a superconducting lumped LC resonator with the inductor L including an array of eight superconducting quantum interference devices (SQUIDs). This amplifier is parametrically pumped by modulating the flux threading the SQUIDs at twice the resonator frequency. Around 5 GHz, a maximum gain of 31 dB, a product amplitude gain × bandwidth above 60 MHz, and a 1 dB compression point of -123 dBm at 20 dB gain are obtained in the nondegenerate mode of operation. Phase-sensitive amplification-deamplification is also measured in the degenerate mode and yields a maximum gain of 37 dB. The compression point obtained is 18 dB above what would be obtained with a single SQUID of the same inductance, due to the smaller nonlinearity of the SQUID array.

Zhou, X.; Schmitt, V.; Bertet, P.; Vion, D.; Wustmann, W.; Shumeiko, V.; Esteve, D.

2014-06-01

72

High-Performance Bound-to-Continuum Quantum-Cascade Lasers for Broad-Gain Applications  

Microsoft Academic Search

Abstract—Based on the bound-to-continuum,active region design, we shall present a high performance continuous-wave (CW) quantum-cascade laser. In contrast to high performance lasers based on a two-phonon resonance transition and a narrow linewidth 165 cm , the device presented here exhibits a spontaneous emission full-width at half-maximum as large as 295 cm . Thus, such devices are very suitable for broadband

Andreas Wittmann; Tobias Gresch; Emilio Gini; Lubos Hvozdara; Nicolas Hoyler; Marcella Giovannini; Jérôme Faist

2008-01-01

73

Repeated allopregnanolone exposure induces weight gain in schedule fed rats on high fat diet.  

PubMed

Ingestion of energy rich high fat diets is one of the determining factors associated with the obesity epidemic. Therefore, much can be learned from studies of obesity-related substances given to animals fed a high fat diet. The progesterone metabolite allopregnanolone is a potent positive modulator of the gamma-aminobutyric acid (GABA)A-receptor, and both allopregnanolone and GABA have been implicated in evoking hyperphagia. In this study, food intake and body weight gain were investigated during repeated allopregnanolone exposure. Male Wistar rats were studied when fed chow ad libitum, with chow access for 4h per day or with 45% high fat pellets for 4h per day. Rats on the high fat diet were separated into obesity prone and obesity resistant individuals. Subcutaneous injections of allopregnanolone were given once daily over five consecutive days. Repeated exposure to allopregnanolone lead to increased weight gain, significantly so in schedule fed rats on a high fat diet. The increased weight gain was correlated to an increased energy intake. Both obesity resistant and obesity prone rats responded to allopregnanolone with increased weight gain. Obesity resistant rats treated with allopregnanolone increased their energy intake and ate as much as vehicle treated obesity prone rats. Their weight gain was also increased to the level of obesity prone rats injected with just the vehicle carrier oil. Thus, it appears that allopregnanolone may be one of the endogenous factors involved in weight gain, especially when the diet is rich in fat. PMID:25484355

Holmberg, E; Johansson, M; Bäckström, T; Löfgren, M; Haage, D

2015-03-01

74

TA 7.4: A High-Swing 2V CMOSOperational Amplifier with Gain Enhancement usinga Replica Amplifier  

E-print Network

TA 7.4: A High-Swing 2V CMOSOperational Amplifier with Gain Enhancement usinga Replica Amplifier output resistance, butby matching main andreplica amplifiers, high effectiveopen-stageamplifiercircuitdemon- strates gain enhancementfor low-voltage applications. Consider a transconductance amplifier

Lee, Hae-Seung "Harry"

75

DEMONSTRATION OF 3D EFFECTS WITH HIGH GAIN AND EFFICIENCY IN A UV FEL OSCILLATOR  

SciTech Connect

We report on the performance of a high gain UV FEL oscillator operating on an energy recovery linac at Jefferson Lab. The high brightness of the electron beam leads to both gain and efficiency that cannot be reconciled with a one-dimensional model. Three-dimensional simulations do predict the performance with reasonable precision. Gain in excess of 100% per pass and an efficiency close to 1/2NW, where NW is the number of wiggler periods, is seen. The laser mirror tuning curves currently permit operation in the wavelength range of 438 to 362 nm. Another mirror set allows operation at longer wavelengths in the red with even higher gain and efficiency.

Stephen Benson; George Biallas; Keith Blackburn; James Boyce; Donald Bullard; James Coleman; Cody Dickover; David Douglas; Forrest Ellingsworth; Pavel Evtushenko; Carlos Hernandez-Garcia; Christopher Gould; Joseph Gubeli; David Hardy; Kevin Jordan; John Klopf; James Kortze; Robert Legg; Matthew Marchlik; Steven Moore; George Neil; Thomas Powers; Daniel Sexton; Michelle D. Shinn; Christopher Tennant; Richard Walker; Anne Watson; Gwyn Williams; Frederick Wilson; Shukui Zhang

2011-03-01

76

Photonic band-gap materials for high-gain printed circuit antennas  

Microsoft Academic Search

It is found through a vector integral-equation analysis and the reciprocity theorem that the gain of a microstrip antenna can be greatly enhanced with a photonic band-gap material layer either as the substrate or the superstrate. The beam angle is found to coincide with that of a leaky-wave mode of a planar-grating structure. This observation suggests that high gain is

Hung-Yu David Yang; Nicolaos G. Alexopoulos; Eli Yablonovitch

1997-01-01

77

Highly reliable & wideband digital multi beamforming horn array antenna with gain adjustment capabilities for space applications  

Microsoft Academic Search

This paper discusses design & measurement techniques for highly reliable & wideband Digital Multi beamforming Horn Array Antenna with gain adjustment capabilities for Space Applications. Complexity of feeding network has been reduced by many folds with the use of 24 dual coaxial fed circularly polarized conical horn antennas providing an excellent axial ratio of <2 dB for entire array highly

Syed Azhar Hasan

2011-01-01

78

Low pellet gain and high efficiency icf power plant model by MHD power generation  

Microsoft Academic Search

We propose a low pellet gain and high efficiency inertial confinement fusion (ICF) power generation system using a magnetohydrodynamic (MHD) power generation, and employ analytical comparative studies for power generation system options. When the thermal output at high temperature (about 2000–2400K) can be extracted from a fusion reactor, only an MHD generator can be used and can convert efficiently ICF

Takashi Kikuchi; Nob. Harada

2000-01-01

79

Development and Testing of a High-Gain Magnetic Flux Compression Generator  

Microsoft Academic Search

The performance of a high-gain FCG is often limited by internal electrical breakdown caused by the high voltage generated during operation. Modern diagnostic techniques provide the opportunity to diagnose internal breakdowns so that generator designs can be improved. This paper describes the internal breakdowns observed in the JAKE FCG developed at the AFRL during the late 1990's. A revision to

J. V. Parker; T. C. Cavazos; C. E. Roth; J. H. Degnan; G. F. Kiuttu; F. M. Lehr

2006-01-01

80

High-gain X-ray free electron laser by beat-wave terahertz undulator  

NASA Astrophysics Data System (ADS)

The THz undulator has a higher gain to realize a much brighter X-ray at saturation, compared with the optical undulator under the same undulator strength and beam quality. In order to fill the high-power THz gap and realize the THz undulator, two superimposed laser pulses at normal incidence to the electron-beam moving direction form an equivalent high-field THz undulator by the frequency difference to realize the high-gain X-ray Free electron laser. The pulse front tilt of lateral fed lasers is used to realize the electron-laser synchronic interaction. By PIC simulation, a higher gain and a larger X-ray radiation power by the beat wave THz undulator could be realized, compared with the optical undulator for the same electron beam parameters.

Chang, Chao; Hei, DongWei; Pellegrin, Claudio; Tantawi, Sami

2013-12-01

81

Spontaneous Steinbeck: The Influence of Arts Integration, Primarily Spontaneous Painting, on the Reader Response of High School Juniors to "The Grapes of Wrath"  

ERIC Educational Resources Information Center

This paper addresses my experience with a group of 11th grade students and their reading of The Grapes of Wrath (1939, 2002) by John Steinbeck. I questioned how the application of visual arts integration strategies, specifically the use of spontaneously created paintings, might influence the reader responses of my high school junior-level…

Klasek, Catherine Huey

2010-01-01

82

High electron gain from single-walled carbon nanotubes stimulated by interaction with an electron beam  

NASA Astrophysics Data System (ADS)

Carbon nanotubes are excellent electron emitters due to their sharp geometry and high electrical conductivity and mechanical stability. It has previously been shown that an electron beam hitting the tip of a nanotube biased near the threshold of field-emission can stimulate the emission of a large number of electrons from the nanotube tip. Here we present a detailed characterization of this so-called electron-stimulated field-emission phenomenon. Electron gains of up to 2300 were obtained. We also discuss possible direct and indirect electron-nanotube interaction mechanisms responsible for this high gain. This effect has a good potential for vacuum nanoelectronic applications.

Michan, Mario; Yaghoobi, Parham; Wong, Bertin; Nojeh, Alireza

2010-05-01

83

A novel 3-stage structure for a low-noise, high-gain and gain-flattened L-band erbium doped fiber amplifier.  

PubMed

The configuration of the novel three-stage L-band erbium-doped fiber amplifier with very large and flat gain and very low noise figure presented in this paper uses the forward ASE (amplified spontaneous emission) from the first section of the EDF (erbium-doped fiber) and the backward ASE from the third section of the EDF (both serve as the secondary pump sources of energy) to pump the second EDF. To improve the pump efficiency, the power of the pump is split into two parts (with a ratio of e.g. 2:7). The characteristics of this L-band EDFA are studied on the basis of the Giles Model with ASE. PMID:15323009

Qiang, Ze-xuan; He, Sai-ling; Zhang, Xu-liang; Shen, Lin-fang

2004-09-01

84

Three-dimensional analysis of harmonic generation in high-gain free-electron lasers  

PubMed

In a high-gain free-electron laser (FEL) employing a planar undulator, strong bunching at the fundamental wavelength can drive substantial bunching and power levels at the harmonic frequencies. In this paper we investigate the three-dimensional evolution of harmonic radiation based on the coupled Maxwell-Klimontovich equations that take into account nonlinear harmonic interactions. Each harmonic field is a sum of a linear amplification term and a term driven by nonlinear harmonic interactions. After a certain stage of exponential growth, the dominant nonlinear term is determined by interactions of the lower nonlinear harmonics and the fundamental radiation. As a result, the gain length, transverse profile, and temporal structure of the first few harmonics are eventually governed by those of the fundamental. Transversely coherent third-harmonic radiation power is found to approach 1% of the fundamental power level for current high-gain FEL projects. PMID:11102089

Huang; Kim

2000-11-01

85

Application of variable-gain output feedback for high-alpha control  

NASA Technical Reports Server (NTRS)

A variable-gain, optimal, discrete, output feedback design approach that is applied to a nonlinear flight regime is described. The flight regime covers a wide angle-of-attack range that includes stall and post stall. The paper includes brief descriptions of the variable-gain formulation, the discrete-control structure and flight equations used to apply the design approach, and the high performance airplane model used in the application. Both linear and nonlinear analysis are shown for a longitudinal four-model design case with angles of attack of 5, 15, 35, and 60 deg. Linear and nonlinear simulations are compared for a single-point longitudinal design at 60 deg angle of attack. Nonlinear simulations for the four-model, multi-mode, variable-gain design include a longitudinal pitch-up and pitch-down maneuver and high angle-of-attack regulation during a lateral maneuver.

Ostroff, Aaron J.

1990-01-01

86

Spontaneous Emission Lifetime of a Single Trapped Ca+ Ion in a High Finesse Cavity  

Microsoft Academic Search

We investigate the spontaneous emission lifetime of a single trapped 40Ca+ ion placed at different positions in the vacuum standing wave inside a high finesse cavity which is stabilized to the atomic transition. The lifetime is measured by quantum state detection after pi-pulse excitation. The result for the natural lifetime of the D5\\/2 metastable state of 1161(22)ms agrees, within 1

A. Kreuter; C. Becher; G. P. Lancaster; A. B. Mundt; C. Russo; H. Häffner; C. Roos; J. Eschner; F. Schmidt-Kaler; R. Blatt

2004-01-01

87

Innovative High-Gain Corrugated Horn Antenna Combining Horizontal and Vertical Corrugations  

Microsoft Academic Search

An innovative kind of corrugated horn antenna is proposed within this letter, the profile of the horn is based on the combination of horizontal and vertical corrugations. The main advantage of these profiles is the possibility of combining high-gain with short profiles, meanwhile keeping the main performances of the conventional corrugated horns. Besides, this horn results in an easier manufacture

Jorge Teniente; Ramón Gonzalo; C. Del-Rio

2006-01-01

88

An Overview of High-Gain Targets for Inertial Fusion Energy  

E-print Network

An Overview of High-Gain Targets for Inertial Fusion Energy L. John Perkins Lawrence Livermore Fusion Energy L. John Perkins Lawrence Livermore National Laboratory This work was performed under/U.Bordeaux)! · A.Casner (CEA, France)! · !M.Roth (Technical University of Darmstadt/GSI, Germany)! · !S

89

Ilchmann, Achim ; Townley, Stuart: Adaptive Sampling Control of High-Gain Stabilizable Systems  

E-print Network

Ilchmann, Achim ; Townley, Stuart: Adaptive Sampling Control of High-Gain Stabilizable Systems;IEEE TRANSACTIONS ON AUTOMATIC CONTROL, VOL. 44, NO. 10, OCTOBER 1999 1961 Adaptive Sampling Control that proportional output feedback control can stabilize any relative-degree one, minimum-phase system if the sign

Knobloch,Jürgen

90

A broadband and high-gain metamaterial microstrip antenna Le-Wei Li,1,a  

E-print Network

A broadband and high-gain metamaterial microstrip antenna Le-Wei Li,1,a Ya-Nan Li,2 Tat Soon Yeo,2-patterned metamaterial concepts. Based on an ordinary patch antenna, the antenna has isolated triangle gaps and crossed of negative index metamaterial. It is shown to have great impact on the antenna performance enhancement

Floreano, Dario

91

Femtosecond Ti:sapphire cryogenic amplifier with high gain and MHz  

E-print Network

Femtosecond Ti:sapphire cryogenic amplifier with high gain and MHz repetition rate Aur´elien Dantan-pass cryogenic Ti:sapphire amplifier. The setup involves a negative GVD mirrors recompression stage, and operates. Sekikawa, and S. Watanabe, "Generation of 0.66-TW pulses at 1 kHz by a Ti:sapphire laser," Opt. Lett. 23

Paris-Sud XI, Université de

92

Neural Computation 9, 971983 (1997) Physiological Gain Leads to High ISI Variability in  

E-print Network

Neural Computation 9, 971­983 (1997) Physiological Gain Leads to High ISI Variability in a Simple@phy.ucsf.edu, ken@phy.ucsf.edu Abstract To understand the interspike interval (ISI) variability displayed by visual that have previously been proposed. When ISI's are dominated by post­spike recovery, 1= p N arguments hold

Columbia University

93

High-gain weakly nonlinear flux-modulated Josephson parametric amplifier using a SQUID-array  

E-print Network

High-gain weakly nonlinear flux-modulated Josephson parametric amplifier using a SQUID-array X devices (SQUIDs). This amplifier is parametrically pumped by modulating the flux threading the SQUIDs be obtained with a single SQUID of the same inductance, due to the smaller nonlinearity of the SQUID array. 1

Boyer, Edmond

94

High Average Power Laser Gain Medium With Low Optical Distortion Using A Transverse Flowing Liquid Host  

DOEpatents

A high average power, low optical distortion laser gain media is based on a flowing liquid media. A diode laser pumping device with tailored irradiance excites the laser active atom, ion or molecule within the liquid media. A laser active component of the liquid media exhibits energy storage times longer than or comparable to the thermal optical response time of the liquid. A circulation system that provides a closed loop for mixing and circulating the lasing liquid into and out of the optical cavity includes a pump, a diffuser, and a heat exchanger. A liquid flow gain cell includes flow straighteners and flow channel compression.

Comaskey, Brian J. (Walnut Creek, CA); Ault, Earl R. (Livermore, CA); Kuklo, Thomas C. (Oakdale, CA)

2005-07-05

95

High gain, Fast Scan, Broad Spectrum Parallel Beam Wavelength Dispersive X-ray Spectrometer for SEM  

SciTech Connect

During contract # DE-FG02-ER83545, Parallax Research, Inc. developed a High gain, Fast Scan Broad Spectrum Parallel beam Wavelength Dispersive X-ray Spectrometer for use on Scanning Electron Microscopes (SEM). This new spectrometer allows very fast high resolution elemental analysis of samples in an electron microscope. By comparison to previous WDS spectrometers, it can change from one energy position to another very quickly and has an extended range compared to some similar products.

OHara, David

2009-05-08

96

High-power optically pumped VECSEL using a double-well resonant periodic gain structure  

Microsoft Academic Search

We present the design and fabrication of an optically pumped vertical-external-cavity surface-emitting lasers with double-well resonant periodic gain structure. Each double-well consists of two 4-nm-thick InGaAs strained quantum wells. The double-well provides optimum overlap between the quantum wells and the antinodes of the standing wave of laser signal at high-power and high-temperature operation. The structure is more tolerant to variation

Li Fan; Jörg Hader; Marc Schillgalies; Mahmoud Fallahi; Aramais R. Zakharian; Jerome V. Moloney; Robert Bedford; James T. Murray; Stephan W. Koch; Wolfgang Stolz

2005-01-01

97

Gain-assisted high-dimensional self-trapped laser beams at very low light levels  

SciTech Connect

We propose a scheme to generate high-dimensional self-trapped laser beams at a very low light intensity via atomic coherence. The system we consider is a resonant four-level atomic ensemble, working in an active Raman gain regime and at room temperature. We derive a high-dimensional nonlinear envelope equation for a signal field with a specific saturable nonlinearity. We show that because of the quantum interference effect induced by a control field, the imaginary part of the coefficients of the signal-field envelope equation can be much smaller than their real part. We demonstrate that the system supports gain-assisted, stable, high-dimensional spatial optical solitons and long-lifetime vortices, which can be produced with light power at the microwatt level.

Li Huijun [Institute of Nonlinear Physics, Zhejiang Normal University, Jinhua 321004, Zhejiang (China); Dong Liangwei [Department of Physics, Zhejiang Normal University, Jinhua 321004, Zhejiang (China); Hang Chao [State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062 (China); Huang Guoxiang [Institute of Nonlinear Physics, Zhejiang Normal University, Jinhua 321004, Zhejiang (China); State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062 (China)

2011-02-15

98

Properties of high gain GaAs switches for pulsed power applications  

SciTech Connect

High gain GaAs photoconductive semiconductor switches (PCSS) are being used in a variety of electrical and optical short pulse applications. The highest power application, which the authors are developing, is a compact, repetitive, short pulse linear induction accelerator. The array of PCSS, which drive the accelerator, will switch 75 kA and 250 kV in 30 ns long pulses at 50 Hz. The accelerator will produce a 700 kV, 7kA electron beam for industrial and military applications. In the low power regime, these switches are being used to switch 400 A and 5 kV to drive laser diode arrays which produce 100 ps optical pulses. These short optical pulses are for military and commercial applications in optical and electrical range sensing, 3D laser radar, and high speed imaging. Both types of these applications demand a better understanding of the switch properties to increase switch lifetime, reduce jitter, optimize optical triggering, and improve overall switch performance. These applications and experiments on the fundamental behavior of high gain GaAs switches will be discussed. Open shutter, infra-red images and time-resolved images of the current filaments, which form during high gain switching, will be presented. Results from optical triggering experiments to produce multiple, diffuse filaments for high current repetitive switching will be described.

Zutavern, F.J.; Loubriel, G.M.; Hjalmarson, H.P.; Mar, A.; Helgeson, W.D.; O`Malley, M.W.; Ruebush, M.H. [Sandia National Labs., Albuquerque, NM (United States); Falk, R.A. [OptoMetrix, Inc., Renton, WA (United States)

1997-09-01

99

High-efficiency high-gain monolithic heterostructure FET amplifier at 31 GHz  

NASA Technical Reports Server (NTRS)

A three-stage heterostructure FET monolithic amplifier has achieved a power-added efficiency of 36 percent with 200 mW output and 18 dB gain at 31 GHz. At a higher drain voltage, the output power increases to 280 mW (with 17.5 dB gain and 31 percent PAE) at a power density of 0.7 W/mm. The MMIC chip measures 2.63 x 1.35 sq mm and requires only a single drain bias and a single gate bias.

Tserng, H. Q.; Saunier, P.; Kao, Y.-C.

1993-01-01

100

A comparative study of the spontaneous social interactions of children with high-functioning autism and children with Asperger's disorder  

Microsoft Academic Search

A comparative observational study was undertaken of the spontaneous social interactions of children with high-functioning autism and Asperger's disorder. The sample comprised 20 children with high-functioning autism, 19 children with Asperger's disorder and 17 typically developing children matched on chronological age and overall mental age. A one–zero time sampling technique was used in live coding of the children's spontaneous social

Kathleen Macintosh; Cheryl Dissanayake

2006-01-01

101

Spontaneous high piezoelectricity in poly(vinylidene fluoride) nanoribbons produced by iterative thermal size reduction technique.  

PubMed

We produced kilometer-long, endlessly parallel, spontaneously piezoelectric and thermally stable poly(vinylidene fluoride) (PVDF) micro- and nanoribbons using iterative size reduction technique based on thermal fiber drawing. Because of high stress and temperature used in thermal drawing process, we obtained spontaneously polar ? phase PVDF micro- and nanoribbons without electrical poling process. On the basis of X-ray diffraction (XRD) analysis, we observed that PVDF micro- and nanoribbons are thermally stable and conserve the polar ? phase even after being exposed to heat treatment above the melting point of PVDF. Phase transition mechanism is investigated and explained using ab initio calculations. We measured an average effective piezoelectric constant as -58.5 pm/V from a single PVDF nanoribbon using a piezo evaluation system along with an atomic force microscope. PVDF nanoribbons are promising structures for constructing devices such as highly efficient energy generators, large area pressure sensors, artificial muscle and skin, due to the unique geometry and extended lengths, high polar phase content, high thermal stability and high piezoelectric coefficient. We demonstrated two proof of principle devices for energy harvesting and sensing applications with a 60 V open circuit peak voltage and 10 ?A peak short-circuit current output. PMID:25133594

Kanik, Mehmet; Aktas, Ozan; Sen, Huseyin Sener; Durgun, Engin; Bayindir, Mehmet

2014-09-23

102

Terahertz photonic transmitters with a high-gain open-ended rampart slot array antenna  

NASA Astrophysics Data System (ADS)

We propose to integrate a high-gain open-ended rampart slot array antenna in our edge-coupled terahertz (THz) photonic transmitters. By locating the open circuits at the end of each quarter-wavelength slot antenna, the reflected terahertz wave can constructively interference with the input wave and hence produce higher gain. In addition, the folded feeding networks turn more propagating waves into the effective radiating segments rather than the dispersive surface waves. A THz resonant cavity is also designed under our monolithic THz-wave circuits. A 300-nm gold layer is coated below the substrate to serve as a reflecting mirror to reflect back the THz waves to the antenna. The resonant cavity design not only provides a robust base for post device process but also greatly enhances the gain of antenna. With the design of openended rampart slot array antenna and THz resonant cavity, we demonstrate that the gain of antenna can reach 8~9 dBi.

Huang, Yu-Ru; Chen, Hung-Pin; Chiu, Pei-Chin; Chyi, Jen-Inn; Wang, Bing-Hsiao; Chen, Shih-Yuan; Sun, Chi-Kuang

2010-02-01

103

A differential low-voltage high gain current-mode integrated RF receiver front-end  

NASA Astrophysics Data System (ADS)

A differential low-voltage high gain current-mode integrated RF front end for an 802.11b WLAN is proposed. It contains a differential transconductance low noise amplifier (Gm-LNA) and a differential current-mode down converted mixer. The single terminal of the Gm-LNA contains just one MOS transistor, two capacitors and two inductors. The gate-source shunt capacitors, Cx1 and Cx2, can not only reduce the effects of gate-source Cgs on resonance frequency and input-matching impedance, but they also enable the gate inductance Lg1,2 to be selected at a very small value. The current-mode mixer is composed of four switched current mirrors. Adjusting the ratio of the drain channel sizes of the switched current mirrors can increase the gain of the mixer and accordingly increase the gain of RF receiver front-end. The RF front-end operates under 1 V supply voltage. The receiver RFIC was fabricated using a chartered 0.18 ?m CMOS process. The integrated RF receiver front-end has a measured power conversion gain of 17.48 dB and an input referred third-order intercept point (IIP3) of -7.02 dBm. The total noise figure is 4.5 dB and the power is only 14 mW by post-simulations.

Chunhua, Wang; Minglin, Ma; Jingru, Sun; Sichun, Du; Xiaorong, Guo; Haizhen, He

2011-02-01

104

High-Tc superconducting quantum interference device recordings of spontaneous brain activity: Towards high-Tc magnetoencephalography  

NASA Astrophysics Data System (ADS)

We have performed single- and two-channel high transition temperature (high-Tc) superconducting quantum interference device (SQUID) magnetoencephalography (MEG) recordings of spontaneous brain activity in two healthy human subjects. We demonstrate modulation of two well-known brain rhythms: the occipital alpha rhythm and the mu rhythm found in the motor cortex. We further show that despite higher noise-levels compared to their low-Tc counterparts, high-Tc SQUIDs can be used to detect and record physiologically relevant brain rhythms with comparable signal-to-noise ratios. These results indicate the utility of high-Tc technology in MEG recordings of a broader range of brain activity.

Öisjöen, F.; Schneiderman, J. F.; Figueras, G. A.; Chukharkin, M. L.; Kalabukhov, A.; Hedström, A.; Elam, M.; Winkler, D.

2012-03-01

105

High-gain backup antenna design for Pioneer Venus Orbiter spacecraft  

NASA Technical Reports Server (NTRS)

The development and performance is described of a high-gain antenna designed to serve on the Pioneer Venus Orbiter spacecraft as a backup to the principal high-gain antenna unit in the unlikely event the mechanically despun antenna mechanism malfunctioned. The final design, a center-fed standing wave array of six sleeve dipoles enclosed in a fiber glass radome, performed successfully, as did all the antennas, on the Pioneer Orbiter spacecraft which was launched on May 20, 1978, as part of the Pioneer Venus mission. Photographs of experimental models giving details of design and construction are included, as well as graphs showing measured pattern and impedance matching characteristics of the subject antenna.

Glaser, J. I.

1986-01-01

106

A high-gain 58GHz box-horn array antenna with suppressed grating lobes  

Microsoft Academic Search

A low-profile high-gain antenna array of box horns for the frequency band 57.2-58.2 GHz is presented. The antenna consists of 256 radiating elements divided into two subgroups of 128 elements fed by a rectangular waveguide feed network. The radiating elements are fed in parallel and the waveguides are connected with T-junctions. The matching of the T-junctions is improved with a

Tomas Sehm; Arto Lehto; A. V. Raisanen

1999-01-01

107

Output-feedback control of feedforward nonlinear delayed systems through dynamic high-gain scaling  

Microsoft Academic Search

The output-feedback control problem for nonlinear systems with state and input delays is addressed. Both state and input delays are allowed to be time-varying and uncertain. The class of systems considered consists of a nominal system of feedforward form as well as appended dynamics. A delay-independent robust adaptive feedback is designed based on our recent results on dual dynamic high-gain

Prashanth Krishnamurthy; Farshad Khorrami

2009-01-01

108

High transmission gain inverted-F antenna on low-resistivity Si for wireless interconnect  

Microsoft Academic Search

Inverted-F antennas of 2-mm axial length are designed and fabricated on a low-resistivity silicon substrate (10 ?·cm) using a post back-end-of-line process. For the first time, their performances are measured up to 110 GHz for wireless interconnects. Results show that a sharp resonance can be seen at 61 GHz for the antenna, and a high transmission gain of -46.3 dB

Y. P. Zhang; L. H. Guo; M. Sun

2006-01-01

109

High Gestational Weight Gain Does Not Improve Birth Weight in a Cohort of African American Adolescents  

Microsoft Academic Search

Background: Because pregnant African American women and teensareatriskoflowbirthweight,theyarefrequentlycounseledto strive for gestational weight gains at the upper limits of the Institute of Medicine's recommended ranges. Objective:Theobjectivewastoexaminewhethersuchweightgains improvebirthoutcomesinacohortofdisadvantagedAfricanAmer- ican adolescents of low (19.8), average (19.8 to26.0), or high (26) prepregnancy body mass index (BMI; in kg\\/m2). Design: Data were extracted from the medical charts of 1120 Afri- can American adolescents who received

Jennifer Notkin Nielsen; Frank R. Witter; Shih-Chen Chang; Jeri Mancini; Maureen Schulman Nathanson; Laura E. Caulfield

2006-01-01

110

High-Gain Fully Printed Organic Complementary Circuits on Flexible Plastic Foils  

Microsoft Academic Search

We present several fully printed organic complemen- tary circuits using n- and p-type organic thin-film transistors. n-Type and p-type devices are developed on a flexible poly- ethylene-naphthalate substrate. All organic layers are deposited using a low-cost screen-printing technique. The inverters show a high gain and a switching point at exactly V DD\\/2. A seven-stage voltage-controlled oscillator (VCO) is designed with

A. Daami; E. Bergeret; E. Benevent; P. Pannier; R. Coppard; Mathieu Guerin

2011-01-01

111

Gain reduction due to space charge at high counting rates in multiwire proportional chambers  

SciTech Connect

Measurements with a small MWPC of gas gain reduction, due to ion space charge at high counting rates, have been compared with theoretical predictions. The quantity ln(q/q/sub 0/)/(q/q/sub 0/), where (q/q/sub 0/) is the relative reduced avalanche charge, has been found to be closely proportional to count rate, as predicted. The constant of proportionality is in good agreement with calculations made with a modified version of the original, simplified theory.

Smith, G.C.; Mathieson, E.

1986-10-01

112

Optimization of single-step tapering amplitude and energy detuning for high-gain FELs  

NASA Astrophysics Data System (ADS)

We put forward a method to optimize the single-step tapering amplitude of undulator strength and initial energy tuning of electron beam to maximize the saturation power of high gain free-electron lasers (FELs), based on the physics of longitudinal electron beam phase space. Using the FEL simulation code GENESIS, we numerically demonstrate the accuracy of the estimations for parameters corresponding to the linac coherent light source and the Tesla test facility.

Li, He-Ting; Jia, Qi-Ka

2015-01-01

113

Movement Recognition Technology as a Method of Assessing Spontaneous General Movements in High Risk Infants  

PubMed Central

Preterm birth is associated with increased risks of neurological and motor impairments such as cerebral palsy. The risks are highest in those born at the lowest gestations. Early identification of those most at risk is challenging meaning that a critical window of opportunity to improve outcomes through therapy-based interventions may be missed. Clinically, the assessment of spontaneous general movements is an important tool, which can be used for the prediction of movement impairments in high risk infants. Movement recognition aims to capture and analyze relevant limb movements through computerized approaches focusing on continuous, objective, and quantitative assessment. Different methods of recording and analyzing infant movements have recently been explored in high risk infants. These range from camera-based solutions to body-worn miniaturized movement sensors used to record continuous time-series data that represent the dynamics of limb movements. Various machine learning methods have been developed and applied to the analysis of the recorded movement data. This analysis has focused on the detection and classification of atypical spontaneous general movements. This article aims to identify recent translational studies using movement recognition technology as a method of assessing movement in high risk infants. The application of this technology within pediatric practice represents a growing area of inter-disciplinary collaboration, which may lead to a greater understanding of the development of the nervous system in infants at high risk of motor impairment. PMID:25620954

Marcroft, Claire; Khan, Aftab; Embleton, Nicholas D.; Trenell, Michael; Plötz, Thomas

2015-01-01

114

Gains of ubiquitylation sites in highly conserved proteins in the human lineage  

PubMed Central

Background Post-translational modification of lysine residues of specific proteins by ubiquitin modulates the degradation, localization, and activity of these target proteins. Here, we identified gains of ubiquitylation sites in highly conserved regions of human proteins that occurred during human evolution. Results We analyzed human ubiquitylation site data and multiple alignments of orthologous mammalian proteins including those from humans, primates, other placental mammals, opossum, and platypus. In our analysis, we identified 281 ubiquitylation sites in 252 proteins that first appeared along the human lineage during primate evolution: one protein had four novel sites; four proteins had three sites each; 18 proteins had two sites each; and the remaining 229 proteins had one site each. PML, which is involved in neurodevelopment and neurodegeneration, acquired three sites, two of which have been reported to be involved in the degradation of PML. Thirteen human proteins, including ERCC2 (also known as XPD) and NBR1, gained human-specific ubiquitylated lysines after the human-chimpanzee divergence. ERCC2 has a Lys/Gln polymorphism, the derived (major) allele of which confers enhanced DNA repair capacity and reduced cancer risk compared with the ancestral (minor) allele. NBR1 and eight other proteins that are involved in the human autophagy protein interaction network gained a novel ubiquitylation site. Conclusions The gain of novel ubiquitylation sites could be involved in the evolution of protein degradation and other regulatory networks. Although gains of ubiquitylation sites do not necessarily equate to adaptive evolution, they are useful candidates for molecular functional analyses to identify novel advantageous genetic modifications and innovative phenotypes acquired during human evolution. PMID:23157318

2012-01-01

115

Trigeminal high-frequency stimulation produces short- and long-term modification of reflex blink gain.  

PubMed

Reflex blinks provide a model system for investigating motor learning in normal and pathological states. We investigated whether high-frequency stimulation (HFS) of the supraorbital branch of the trigeminal nerve before the R2 blink component (HFS-B) decreases reflex blink gain in alert rats. As with humans (Mao JB, Evinger C. J Neurosci 21: RC151, 2001), HFS-B significantly reduced blink size in the first hour after treatment for rats. Repeated days of HFS-B treatment produced long-term depression of blink circuits. Blink gain decreased exponentially across days, indicating a long-term depression of blink circuits. Additionally, the HFS-B protocol became more effective at depressing blink amplitude across days of treatment. This depression was not habituation, because neither long- nor short-term blink changes occurred when HFS was presented after the R2. To investigate whether gain modifications produced by HFS-B involved cerebellar networks, we trained rats in a delay eyelid conditioning paradigm using HFS-B as the unconditioned stimulus and a tone as the conditioned stimulus. As HFS-B depresses blink circuits and delay conditioning enhances blink circuit activity, occlusion should occur if they share neural networks. Rats acquiring robust eyelid conditioning did not exhibit decreases in blink gain, whereas rats developing low levels of eyelid conditioning exhibited weak, short-term reductions in blink gain. These results suggested that delay eyelid conditioning and long-term HFS-B utilize some of the same cerebellar circuits. The ability of repeated HFS-B treatment to depress trigeminal blink circuit activity long term implied that it may be a useful protocol to reduce hyperexcitable blink circuits that underlie diseases like benign essential blepharospasm. PMID:24285868

Ryan, Michael; Kaminer, Jaime; Enmore, Patricia; Evinger, Craig

2014-02-01

116

Gyroklystron Design A High-Power, High-Gain, Second Harmonic Gyroklystron for K-  

E-print Network

Parameters · Vc · B0 · Magnetic compression ratio (fm): fm = B0 / Bc r z Vc -500kV 0kV #12;Choose 3 values: Gyroklystron Schematic: B0 Bc z z r #12;Simulating the MIG Beam Properties · Pbeam = 100MW · Velocity ratio · Resonant frequency · Spacing Circuit Properties · Efficiency (): = Pout / Pbeam = Pout / 100MW · Gain

Anlage, Steven

117

Adverse cardiac remodelling in spontaneously hypertensive rats: acceleration by high aerobic exercise intensity  

PubMed Central

In the present study it was hypothesized that voluntary aerobic exercise favours a pro-fibrotic phenotype and promotes adverse remodelling in hearts from spontaneously hypertensive rats (SHRs) in an angiotensin II-dependent manner. To test this, female SHRs at the age of 1 year were started to perform free running wheel exercise. Captopril was used to inhibit the renin–angiotensin system (RAS). Normotensive rats and SHRs kept in regular cages were used as sedentary controls. Training intensity, expressed as mean running velocity, was positively correlated with the left ventricular mRNA expression of TGF-?1, collagen-III and biglycan but negatively correlated with the ratio of sarcoplasmic reticulum Ca2+-ATPase (SERCA)2a to Na+–Ca2+ exchanger (NCX). A pro-fibrotic phenotype was verified by Picrosirius red staining. Sixty-seven per cent of SHRs performing free running wheel exercise died either spontaneously or had to be killed during a 6 month follow-up. In the presence of captopril, aerobic exercise did not show a similar positive correlation between training intensity and the expression of fibrotic markers. Moreover, in SHRs receiving captopril and performing free running wheel exercise, a training intensity-dependent reverse remodelling of the SERCA2a-to-NCX ratio was observed. None of these rats died spontaneously or had to be killed. In captopril-treated SHRs performing exercise, expression of mRNA for decorin, a natural inhibitor of TGF-?1, was up-regulated. Despite these differences between SHR-training groups with and without captopril, positive training effects (lower resting heart rate and no progression of hypertension) were found in both groups. In conclusion, high aerobic exercise induces an angiotensin II-dependent adverse remodelling in chronic pressure overloaded hearts. However, high physical activity can potentially induce reverse remodelling in the presence of RAS inhibition. PMID:22930266

da Costa Rebelo, Rui Manuel; Schreckenberg, Rolf; Schlüter, Klaus-Dieter

2012-01-01

118

A bootstrapped, low-noise, and high-gain photodetector for shot noise measurement  

SciTech Connect

We presented a low-noise, high-gain photodetector based on the bootstrap structure and the L-C (inductance and capacitance) combination. Electronic characteristics of the photodetector, including electronic noise, gain and frequency response, and dynamic range, were verified through a single-frequency Nd:YVO{sub 4} laser at 1064 nm with coherent output. The measured shot noise of 50 ?W laser was 13 dB above the electronic noise at the analysis frequency of 2 MHz, and 10 dB at 3 MHz. And a maximum clearance of 28 dB at 2 MHz was achieved when 1.52 mW laser was illuminated. In addition, the photodetector showed excellent linearities for both DC and AC amplifications in the laser power range between 12.5 ?W and 1.52 mW.

Zhou, Haijun; Yang, Wenhai; Li, Zhixiu; Li, Xuefeng; Zheng, Yaohui, E-mail: yhzheng@sxu.edu.cn [State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006 (China)] [State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006 (China)

2014-01-15

119

A bootstrapped, low-noise, and high-gain photodetector for shot noise measurement.  

PubMed

We presented a low-noise, high-gain photodetector based on the bootstrap structure and the L-C (inductance and capacitance) combination. Electronic characteristics of the photodetector, including electronic noise, gain and frequency response, and dynamic range, were verified through a single-frequency Nd:YVO4 laser at 1064 nm with coherent output. The measured shot noise of 50 ?W laser was 13 dB above the electronic noise at the analysis frequency of 2 MHz, and 10 dB at 3 MHz. And a maximum clearance of 28 dB at 2 MHz was achieved when 1.52 mW laser was illuminated. In addition, the photodetector showed excellent linearities for both DC and AC amplifications in the laser power range between 12.5 ?W and 1.52 mW. PMID:24517749

Zhou, Haijun; Yang, Wenhai; Li, Zhixiu; Li, Xuefeng; Zheng, Yaohui

2014-01-01

120

High-gain dc SQUID magnetometers with NbN nanobridges  

SciTech Connect

This paper reports on high-gain dc SQUIDs using NbN nanobridges fabricated for magnetometers with high sensitivity, and their device parameters and intrinsic energy sensitivity have been evaluated. The slit inductance of the square washer SQUID was reduced by using the co-planar edge structure of the low inductance. The junction capacitance was typically 15 {approximately} 40 ft. The maximum voltage modualtion was about 110 {mu}V for the NbN nanobridge SQUID with an inductance of 0.18nH.

Irie, A.; Hamasaki, K.; Yamashita, T. (Dept. of Electronics, Nagaoka Univ. of Technology, Kamitomioka-Machi 1603-1, Nagoka-shi, Niigata 940-21 (JP)); Matsui, T.; Komiyama, B. (Communication Research Lab., Ministry of Posts and Telecommunication, Koganei, Tokyo 184 (JP))

1991-03-01

121

Percentage of Body Fat and Weight Gain in Participants in the Tehran High School Wrestling Championship  

PubMed Central

Purpose Weight loss in wrestling has been found to be an interesting issue for researchers. In this regard, complications of weight loss in wrestlers before the competitions and their weight gain in course of competitions have been debated in previous studies. The objective of this study was to investigate the extent of weight gain and to estimate the percentage of body fat in participants in the Tehran high school male wrestling championship. Methods This study was a cross sectional survey. Subjects were participants of the Tehran high school male wrestling championship (n = 365). Weight gain in course of competitions and body fat levels (based on skin fold measurements) of subjects were measured. Results Between the first weigh-in of the wrestlers which was done one day before the competitions and the second weigh-in which was conducted immediately before the first round of their first competition (20 hours), 69% of subjects gained on average 1.3±0.9 kg (range: 0.1 to 6.10 kg) or 2.2±1.7% of the wrestler’s weight (range: 0.1 to 9.3). Among the subjects, the mean of fat body percentage was found to be 15.2%. Conclusions Rapid weight loss for matches was prevalent among subjects. It was also found that Iranian wrestlers have a relatively higher body fat percentage in comparison to American wrestlers. Therefore, it can be concluded that weight loss behavior of these wrestlers should be changed from using dehydration methods to using gradual methods of weight loss such as fat reduction methods. PMID:22942998

Kordi, Ramin; Nourian, Ruhollah; Rostami, Mohsen; Wallace, W. Angus

2012-01-01

122

Effects of Bandwidth, Compression Speed, and Gain at High Frequencies on Preferences for Amplified Music  

PubMed Central

This article reviews a series of studies on the factors influencing sound quality preferences, mostly for jazz and classical music stimuli. The data were obtained using ratings of individual stimuli or using the method of paired comparisons. For normal-hearing participants, the highest ratings of sound quality were obtained when the reproduction bandwidth was wide (55 to 16000 Hz) and ripples in the frequency response were small (less than ± 5 dB). For hearing-impaired participants listening via a simulated five-channel compression hearing aid with gains set using the CAM2 fitting method, preferences for upper cutoff frequency varied across participants: Some preferred a 7.5- or 10-kHz upper cutoff frequency over a 5-kHz cutoff frequency, and some showed the opposite preference. Preferences for a higher upper cutoff frequency were associated with a shallow high-frequency slope of the audiogram. A subsequent study comparing the CAM2 and NAL-NL2 fitting methods, with gains slightly reduced for participants who were not experienced hearing aid users, showed a consistent preference for CAM2. Since the two methods differ mainly in the gain applied for frequencies above 4 kHz (CAM2 recommending higher gain than NAL-NL2), these results suggest that extending the upper cutoff frequency is beneficial. A system for reducing “overshoot” effects produced by compression gave small but significant benefits for sound quality of a percussion instrument (xylophone). For a high-input level (80 dB SPL), slow compression was preferred over fast compression. PMID:23172008

2012-01-01

123

Effects of bandwidth, compression speed, and gain at high frequencies on preferences for amplified music.  

PubMed

This article reviews a series of studies on the factors influencing sound quality preferences, mostly for jazz and classical music stimuli. The data were obtained using ratings of individual stimuli or using the method of paired comparisons. For normal-hearing participants, the highest ratings of sound quality were obtained when the reproduction bandwidth was wide (55 to 16000 Hz) and ripples in the frequency response were small (less than ± 5 dB). For hearing-impaired participants listening via a simulated five-channel compression hearing aid with gains set using the CAM2 fitting method, preferences for upper cutoff frequency varied across participants: Some preferred a 7.5- or 10-kHz upper cutoff frequency over a 5-kHz cutoff frequency, and some showed the opposite preference. Preferences for a higher upper cutoff frequency were associated with a shallow high-frequency slope of the audiogram. A subsequent study comparing the CAM2 and NAL-NL2 fitting methods, with gains slightly reduced for participants who were not experienced hearing aid users, showed a consistent preference for CAM2. Since the two methods differ mainly in the gain applied for frequencies above 4 kHz (CAM2 recommending higher gain than NAL-NL2), these results suggest that extending the upper cutoff frequency is beneficial. A system for reducing "overshoot" effects produced by compression gave small but significant benefits for sound quality of a percussion instrument (xylophone). For a high-input level (80 dB SPL), slow compression was preferred over fast compression. PMID:23172008

Moore, Brian C J

2012-09-01

124

Fat substitutes promote weight gain in rats consuming high-fat diets  

PubMed Central

The use of food products designed to mimic the sensory properties of sweet and fat while providing fewer calories has been promoted as a method for reducing food intake and body weight. However, such products may interfere with one mechanism that animals use to regulate energy balance, a learned relationship between the sensory properites of food and the caloric consequences of consuming those foods. Consistent with this hypothesis, previous data have shown that providing rats with sweet tastes that are not associated with the delivery of calories using high-intensity sweeteners results in increased food intake, body weight and adiposity, but only if the diet on which they are maintained also tastes sweet. In the present experiment, we examined whether use of the fat substitute, olestra, would have similar consequences by comparing the effects of consuming high-fat, high-calorie potato chips to the effects of consuming potato chips that sometimes signalled high calories (using high-fat potato chips) and that sometimes signalled lower calories (using non-fat potato chips manufactured with the fat substitute olestra). The results demonstrated that food intake, body weight gain and adiposity were greater for rats that consumed both the high-calorie chips and the low-calorie chips with olestra compared to rats that consumed consuming only the high-calorie chips, but only if animals were also consuming a chow diet that was high in fat and calories. When animals were maintained on a low-fat chow diet, intake, weight gain, and adiposity did not differ significantly based on chip type. However, rats previously exposed to both the low-calorie chips with olestra and the high-calorie chips exhibited increased body weight gain, food intake and adiposity when they were provided with a high fat, high calorie chow diet, even though the potato chips were no longer available. This suggests that the experience with the chips containing olestra affected the ability to predict high calories based on the sensory properties associated with fat. These results extend the generality of previous findings that interfering with a predictive relationship between sensory properties of foods and calories may contribute to dysregulation of energy balance, overweight and obesity. PMID:21688890

Swithers, Susan E.; Ogden, Sean B.; Davidson, Terry L.

2011-01-01

125

Highly accurate measurements of the spontaneous fission half-life of 240,242Pu  

NASA Astrophysics Data System (ADS)

Fast spectrum neutron-induced fission cross-section data for transuranic isotopes are of special demand from the nuclear data community. In particular highly accurate data are needed for the new generation IV nuclear applications. The aim is to obtain precise neutron-induced fission cross sections for 240Pu and 242Pu. To do so, accurate data on spontaneous fission half-lives must be available. Also, minimizing uncertainties in the detector efficiency is a key point. We studied both isotopes by means of a twin Frisch-grid ionization chamber with the goal of improving the present data on the neutron-induced fission cross section. For the two plutonium isotopes the high ?-particle decay rates pose a particular problem to experiments due to piling-up events in the counting gas. Argon methane and methane were employed as counting gases, the latter showed considerable improvement in signal generation due to its higher drift velocity. The detection efficiency for both samples was determined, and improved spontaneous fission half-lives were obtained with very low statistical uncertainty (0.13% for 240Pu and 0.04% for 242Pu): for 240Pu, T1/2,SF=1.165×1011 yr (1.1%), and for 242Pu, T1/2,SF=6.74×1010 yr (1.3%). Systematic uncertainties are due to sample mass (0.4% for 240Pu and 0.9% for 242Pu) and efficiency (1%).

Salvador-Castiñeira, P.; Bry?, T.; Eykens, R.; Hambsch, F.-J.; Moens, A.; Oberstedt, S.; Sibbens, G.; Vanleeuw, D.; Vidali, M.; Pretel, C.

2013-12-01

126

Low-Power, High-Gain V-Band CMOS Low Noise Amplifier for Microwave Radiometer Applications  

Microsoft Academic Search

A low power and high gain V-band CMOS low-noise amplifier (LNA) is proposed in this letter with a three-stage cas- code topology. Using the gate-inductive gain-peaking technique to boost the gain, the proposed LNA achieves a good figure of merit (FOM) with less power consumption. This proposed LNA is fabri- cated in a 0.13 RF CMOS process, which achieves a

Chun-Chieh Huang; Hsin-Chih Kuo; Tzuen-Hsi Huang; Huey-Ru Chuang

2011-01-01

127

Redesign of a Variable-Gain Output Feedback Longitudinal Controller Flown on the High-Alpha Research Vehicle (HARV)  

NASA Technical Reports Server (NTRS)

This paper describes a redesigned longitudinal controller that flew on the High-Alpha Research Vehicle (HARV) during calendar years (CY) 1995 and 1996. Linear models are developed for both the modified controller and a baseline controller that was flown in CY 1994. The modified controller was developed with three gain sets for flight evaluation, and several linear analysis results are shown comparing the gain sets. A Neal-Smith flying qualities analysis shows that performance for the low- and medium-gain sets is near the level 1 boundary, depending upon the bandwidth assumed, whereas the high-gain set indicates a sensitivity problem. A newly developed high-alpha Bode envelope criterion indicates that the control system gains may be slightly high, even for the low-gain set. A large motion-base simulator in the United Kingdom was used to evaluate the various controllers. Desired performance, which appeared to be satisfactory for flight, was generally met with both the low- and medium-gain sets. Both the high-gain set and the baseline controller were very sensitive, and it was easy to generate pilot-induced oscillation (PIO) in some of the target-tracking maneuvers. Flight target-tracking results varied from level 1 to level 3 and from no sensitivity to PIO. These results were related to pilot technique and whether actuator rate saturation was encountered.

Ostroff, Aaron J.

1998-01-01

128

Parasitic lasing suppression in high gain femtosecond petawatt Ti:sapphire amplifier.  

PubMed

New parasitic lasing suppression techniques are developed and high gain amplification is demonstrated in a petawatt level Ti:sapphire amplifier based on the chirped pulse amplification (CPA) scheme. Cladding the large aperture Ti:sapphire with refractive-index matched liquid doped with absorber suppresses the transverse lasing. The acousto-optic programmable dispersive filter (AOPDF) is used to realize side-lobe suppression in the temporal profile of the compressed pulse. The 800 nm laser output with peak power of 0.89 PW and pulse width of 29.0 fs is demonstrated. PMID:19550819

Liang, Xiaoyan; Leng, Yuxin; Wang, Cheng; Li, Chuang; Lin, Lihuang; Zhao, Baozhen; Jiang, Yunhua; Lu, Xiaoming; Hu, Minyuan; Zhang, Chunmei; Lu, Haihe; Yin, Dingjun; Jiang, Yongliang; Lu, Xingqiang; Wei, Hui; Zhu, Jianqiang; Li, Ruxin; Xu, Zhizhan

2007-11-12

129

Method and system for modulation of gain suppression in high average power laser systems  

DOEpatents

A high average power laser system with modulated gain suppression includes an input aperture associated with a first laser beam extraction path and an output aperture associated with the first laser beam extraction path. The system also includes a pinhole creation laser having an optical output directed along a pinhole creation path and an absorbing material positioned along both the first laser beam extraction path and the pinhole creation path. The system further includes a mechanism operable to translate the absorbing material in a direction crossing the first laser beam extraction laser path and a controller operable to modulate the second laser beam.

Bayramian, Andrew James (Manteca, CA)

2012-07-31

130

High Gain Antenna System Deployment Mechanism Integration, Characterization, and Lessons Learned  

NASA Technical Reports Server (NTRS)

The integration and deployment testing of the High Gain Antenna System for the Global Precipitation Measurement mission is summarized. The HGAS deployment mechanism is described. The gravity negation system configuration and its influence on vertical, ground-based, deployment tests are presented with test data and model predictions. A focus is made on the late discovery and resolution of a potentially mission degrading deployment interference condition. The interaction of the flight deployment mechanism, gravity negation mechanism, and use of dynamic modeling is described and lessons learned presented.

Parong, Fil; Russell, Blair; Garcen, Walter; Rose, Chris; Johnson, Chris; Huber, Craig

2014-01-01

131

High-accuracy picosecond characterization of gain-switched laser diodes  

SciTech Connect

A unique combination of the time-correlated photon-counting technique and single-photon avalanche diode detectors gives an accurate characterization of gain-switched semiconductor lasers with picosecond resolution. The high sensitivity and the clean shape of the time response reveal even small features (reflections and relaxation oscillations), making a true optimization of the laser-diode operation possible. The technique outperforms the standard characterization with ultrafast p-i-n photodiodes and a sampling oscilloscope. In addition, compared with other methods, it has favorable features that greatly simplify the measurement.

Cova, S.; Lacaita, A.; Ghioni, M.; Ripamonti, G. (Dipartimento di Elettronica, Politecnico di Milano, Piazza Leonardo da Vinci, 32 Milano, 20133 Italy (IT))

1989-12-15

132

Enhancing the performance of a high-gain free electron laser operating at millimeter wavelengths  

SciTech Connect

A high-gain, high extraction efficiency, free electron laser (FEL) amplifier operating at the Experimental Test Accelerator (ETA) at 34.6 GHz has demonstrated a small signal gain of 13.4 dB/m. With a 30 kW input signal, the amplifier has produced a saturated output of 80 MW and a 5% extraction efficiency. Comparison of these results with a linear model at small signal levels indicates that the amplifier can deliver saturated output starting from noise, if the brightness of the electron beam is sufficiently high. The brightness of the ETA is far below that possible with optimized choice of practical design characteristics such as peak voltage, cathode type, gun electrode geometry, and focusing field topology. In particular, the measured brightness of the ETA injector is limited by plasma effects from the present cold, plasma cathode. As part of a coordinated theoretical and experimental effort to improve injector performance, we are using the EBQ gun design code to explore the current limits of gridless, relativistic, Pierce columns with moderate current density (>50 A/cm/sup 2/) at the cathode. The chief component in our experimental effort is a readily modified electron gun that will allow us to test many candidate cathode materials, types, and electrode geometries at field stresses up to 1 MV/cm. 8 references, 5 figures.

Barletta, W.A.; Anderson, B.; Fawley, W.M.; Neil, V.K.; Orzechowski, T.J.; Prosnitz, D.; Scharlemann, E.T.; Yarema, S.M.; Paul, A.C.; Hopkins, D.

1984-10-25

133

Technology developments and first measurements of Low Gain Avalanche Detectors (LGAD) for high energy physics applications  

NASA Astrophysics Data System (ADS)

This paper introduces a new concept of silicon radiation detector with intrinsic multiplication of the charge, called Low Gain Avalanche Detector (LGAD). These new devices are based on the standard Avalanche Photo Diodes (APD) normally used for optical and X-ray detection applications. The main differences to standard APD detectors are the low gain requested to detect high energy charged particles, and the possibility to have fine segmentation pitches: this allows fabrication of microstrip or pixel devices which do not suffer from the limitations normally found [1] in avalanche detectors. In addition, a moderate multiplication value will allow the fabrication of thinner devices with the same output signal of standard thick substrates. The investigation of these detectors provides important indications on the ability of such modified electrode geometry to control and optimize the charge multiplication effect, in order to fully recover the collection efficiency of heavily irradiated silicon detectors, at reasonable bias voltage, compatible with the voltage feed limitation of the CERN High Luminosity Large Hadron Collider (HL-LHC) experiments [2]. For instance, the inner most pixel detector layers of the ATLAS tracker will be exposed to fluences up to 2×1016 1 MeV neq/cm2, while for the inner strip detector region fluences of 1×1015 neq/cm2 are expected. The gain implemented in the non-irradiated devices must retain some effect also after irradiation, with a higher multiplication factor with respect to standard structures, in order to be used in harsh environments such those expected at collider experiments.

Pellegrini, G.; Fernández-Martínez, P.; Baselga, M.; Fleta, C.; Flores, D.; Greco, V.; Hidalgo, S.; Mandi?, I.; Kramberger, G.; Quirion, D.; Ullan, M.

2014-11-01

134

Design of a novel mixer with high gain and linearity improvement for DRM/DAB applications  

NASA Astrophysics Data System (ADS)

This paper focuses on a new design of a down-conversion mixer for a low-IF wideband receiver. Based on the folded structure and differential multiple gated transistor (DMGTR) technique, a novel quadrature mixer with a high conversion gain, a moderate linearity, and a moderate NF is proposed. The mixer is designed and implemented in a 0.18-?m CMOS process, and can operate in a frequency range from 150 kHz to 1.5 GHz. The circuit performance is confirmed by both simulation and measurement results. The measurement results exhibit a peak conversion gain of 13.35 dB, a high third order input referred intercept point of 14.85 dBm, and a moderate single side band noise figure of 10.67 dB. Moreover, the whole quadrature mixer core occupies a compact die area of 0.122 mm2. It consumes a current of 3.96 mA (excluding the output buffers) under a single supply voltage of 1.8 V.

Yiqiang, Wu; Zhigong, Wang; Jian, Xu; Jian, Wang; Ouli, Zhang; Lu, Tang

2013-01-01

135

A Comparative Study of the Spontaneous Social Interactions of Children with High-Functioning Autism and Children with Asperger's Disorder  

ERIC Educational Resources Information Center

A comparative observational study was undertaken of the spontaneous social interactions of children with high-functioning autism and Asperger's disorder. The sample comprised 20 children with high-functioning autism, 19 children with Asperger's disorder and 17 typically developing children matched on chronological age and overall mental age. A…

Macintosh, Kathleen; Dissanayake, Cheryl

2006-01-01

136

Progress in laboratory high gain ICF (inertial confinement fusion): Prospects for the future  

SciTech Connect

Inertial confinement fusion (ICF), a thermonuclear reaction in a small (/approximately/5 mm diameter) fuel capsule filled with a few milligrams of deuterium and tritium, has been the subject of very fruitful experimentation since the early 1970's. High gain ICF is now on the threshold of practical applications. With a Laboratory Microfusion Facility (LMF), these applications will have major implications for national defense, basic and applied science, and power production. With a driver capable of delivering about 10 MJ in a 10-ns pulse at an intensity of /approximately/3 /times/ 10/sup 14/ W/cm/sup 2/, an appropriately configured cryogenic capsule could be compressed to a density of about 200 g/cm/sup 3/ and a temperature of 3--5 keV. Under these conditions, up to 10 mg of DT could be ignited, and with a burn efficiency of about 30%, release up to 1000 MJ of fusion energy, an energy gain of about 100. A thousand megajoules is equivalent to about one quarter ton of TNT, or about 7 gallons of oil--an amount of energy tractable under laboratory conditions and potentially very useful for a variety of applications. 61 refs., 33 figs.

Storm, E.; Lindl, J.D.; Campbell, E.M.; Bernat, T.P.; Coleman, L.W.; Emmett, J.L.; Hogan, W.J.; Hunt, J.T.; Krupke, W.F.; Lowdermilk, W.H.

1988-01-01

137

Virtual dielectric waveguide mode description of a high-gain free-electron laser. I. Theory  

NASA Astrophysics Data System (ADS)

A set of mode-coupled excitation equations for the slowly growing amplitudes of dielectric waveguide eigenmodes is derived as a description of the electromagnetic signal field of a high-gain free-electron laser (FEL), including the effects of longitudinal space charge. This approach of describing the field basis set has notable advantages for FEL analysis in providing an efficient characterization of eigenmodes, and in allowing a clear connection to free-space propagation of the input (seeding) and output radiation. The formulation describes the entire evolution of the radiation wave through the linear gain regime, prior to the onset of saturation, with arbitrary initial conditions. By virtue of the flexibility in the expansion basis, this technique can be used to find the direct coupling and amplification of a particular mode. A simple transformation converts the derived coupled differential excitation equations into a set of coupled algebraic equations and yields a matrix determinant equation for the FEL eigenmodes. A quadratic index medium is used as a model dielectric waveguide to obtain an expression for the predicted spot size of the dominant system eigenmode, in the approximation that it is a single Gaussian mode.

Hemsing, Erik; Gover, Avraham; Rosenzweig, James

2008-06-01

138

Spontaneous growth of diamond from MnNi solvent-catalyst using opposed anvil-type high-pressure apparatus  

NASA Astrophysics Data System (ADS)

In this paper an overview of the application of opposed anvil-type high-pressure and high-temperature apparatus for spontaneous growth of diamond crystals by solvent-catalyst technique is presented. The process makes use of a molten Mn47Ni53 catalyst to initiate the graphite-diamond transformation reaction. The pressure and temperature requirements to obtain reproducible spontaneous diamond crystallization were around 52.5-54 kbar and 1270-1320 °C. The crystals had well-shaped cubo-structured morphology with the {100} and {111} faces and grain sizes of 0.2-0.5 mm. This work can stimulate future experimental exploration of spontaneous diamond crystallization by using other solvent-catalyst metals.

Zhigadlo, N. D.

2014-06-01

139

Evidence for High Frequency of Chromosomal Mosaicism in Spontaneous Abortions Revealed by Interphase FISH Analysis  

Microsoft Academic Search

Numerical chromosomal imbalances are a common feature of spontaneous abortions. However, the incidence of mosaic forms of chromosomal abnormalities has not been evaluated. We have applied interphase multicolor fluorescence in situ hybridization using original DNA probes for chromosomes 1, 9, 13, 14, 15, 16, 18, 21, 22, X, and Y to study chromosomal abnormalities in 148 specimens of spontaneous abortions.

Svetlana G. Vorsanova; Alexei D. Kolotii; Ivan Y. Iourov; Viktor V. Monakhov; Elena A. Kirillova; Ilia V. Soloviev; Yuri B. Yurov

2005-01-01

140

Calibration of Gimbaled Platforms: The Solar Dynamics Observatory High Gain Antennas  

NASA Technical Reports Server (NTRS)

Simple parameterization of gimbaled platform pointing produces a complete set of 13 calibration parameters-9 misalignment angles, 2 scale factors and 2 biases. By modifying the parameter representation, redundancy can be eliminated and a minimum set of 9 independent parameters defined. These consist of 5 misalignment angles, 2 scale factors, and 2 biases. Of these, only 4 misalignment angles and 2 biases are significant for the Solar Dynamics Observatory (SDO) High Gain Antennas (HGAs). An algorithm to determine these parameters after launch has been developed and tested with simulated SDO data. The algorithm consists of a direct minimization of the root-sum-square of the differences between expected power and measured power. The results show that sufficient parameter accuracy can be attained even when time-dependent thermal distortions are present, if measurements from a pattern of intentional offset pointing positions is included.

Hashmall, Joseph A.

2006-01-01

141

Monoclinic m-LaVO4—a novel high Raman gain SRS-active crystal  

NASA Astrophysics Data System (ADS)

Monoclinic m-LaVO4, having a monazite-type structure and being known as a host crystal for Nd3+-lasants, is an attractive ?(3)-nonlinear optical material for Raman laser converters. This paper presents the stimulated Raman scattering (SRS) spectroscopy of m-LaVO4 in the visible and near-IR spectral range using picosecond laser excitation. High-order SRS and Raman-induced four-wave parametric mixing processes result in an almost two-octave-wide Stokes and anti-Stokes frequency comb. All the measured spectral lines were assigned to the participating molecular vibration modes of the studied vanadate. Finally, an estimation of the steady-state Raman gain coefficient for first Stokes generation in near-IR was performed.

Kaminskii, A. A.; Yu, H.; Zhang, H.; Wang, J.; Lux, O.; Rhee, H.; Eichler, H. J.; Yoneda, H.; Shirakawa, A.; Zhang, J.; Tang, G.

2014-12-01

142

Compact gain-switching linearly polarized high-power Yb pulse fiber laser  

NASA Astrophysics Data System (ADS)

A compact gain-switching pumped linearly polarized high-power Yb pulse fiber laser is experimentally demonstrated. The laser was mainly composed of a piece of polarization-maintaining (PM) Yb-doped fiber and a pair of PM FBGs. Three fiber pig-tailed laser diodes (LDs) were applied as the pump source through a (6+1)?×?1 fiber coupler and configured in a pulse-working scheme. Stable pulse operation was achieved with repetition rate up to 200?kHz, pulse duration of 120?ns and a spectral FWHM of 0.08?nm. A maximum average laser output power of 21?W was obtained at 200?kHz with respect to the pump power of 30.3?W. The polarization extinction ratio was as good as 15?dB.

Wei, K. H.; Cai, S. S.; Jiang, P. P.; Hua, D. C.; Yan, Y. X.; Wu, B.; Shen, Y. H.

2014-08-01

143

A gain-of-function positive-selection expression plasmid that enables high-efficiency cloning.  

PubMed

Directed enzyme evolution is now a routine approach to improve desirable biocatalytic properties. When only a low-throughput screen is available to detect improved variants from a mutant gene library, it is imperative that cloning efficiency be maximized during library synthesis to avoid wasting effort screening empty plasmids. To achieve this we developed pUCXKT, a gain-of-function positive selection expression vector. Insertion of genes amplified using a specialized downstream PCR primer restores key regulatory and genetic elements necessary for co-expression of a kanamycin resistance marker adjacent to the pUCXKT cloning region. We show that pUCXKT enables 100 % cloning efficiency as well as high-level expression of inserted genes. Unlike previous positive selection expression plasmids, the strategy we used to design pUCXKT is readily adaptable to different vector backbones, antibiotic marker genes, and multiple cloning regions. PMID:25257589

Prosser, Gareth A; Williams, Elsie M; Sissons, Jack A; Walmsley, Katherine E; Parker, Madeleine R; Ackerley, David F

2015-02-01

144

High-gain inverters based on WSe2 complementary field-effect transistors.  

PubMed

In this work, the operation of n- and p-type field-effect transistors (FETs) on the same WSe2 flake is realized,and a complementary logic inverter is demonstrated. The p-FET is fabricated by contacting WSe2 with a high work function metal, Pt, which facilities hole injection at the source contact. The n-FET is realized by utilizing selective surface charge transfer doping with potassium to form degenerately doped n+ contacts for electron injection. An ON/OFF current ratio of >10(4) is achieved for both n- and p-FETs with similar ON current densities. A dc voltage gain of >12 is measured for the complementary WSe2 inverter. This work presents an important advance toward realization of complementary logic devices based on layered chalcogenide semiconductors for electronic applications. PMID:24684575

Tosun, Mahmut; Chuang, Steven; Fang, Hui; Sachid, Angada B; Hettick, Mark; Lin, Yongjing; Zeng, Yuping; Javey, Ali

2014-05-27

145

Image-Guided Radio-Frequency Gain Calibration for High-Field MRI  

PubMed Central

High-field (? 3T) MRI provides a means to increase the signal-to-noise ratio, due to its higher tissue magnetization compared with 1.5T. However, both the static magnetic field (B0) and the transmit radio-frequency (RF) field (B1+) inhomogeneities are comparatively higher than those at 1.5T. These challenging factors at high-field strengths make it more difficult to accurately calibrate the transmit RF gain using standard RF calibration procedures. An image-based RF calibration procedure was therefore developed, in order to accurately calibrate the transmit RF gain within a specific region-of-interest (ROI). Using a single-shot ultra-fast gradient echo pulse sequence with centric k-space reordering, a series of “saturation-no-recovery” images was acquired by varying the flip angle of the preconditioning pulse. In the resulting images, the signal null occurs in regions where the flip angle of the preconditioning pulse is 90°. For a given ROI, the mean signal can be plotted as a function of the nominal flip angle, and the resulting curve can be used to quantitatively identify the signal null. This image-guided RF calibration procedure was evaluated through phantom and volunteer imaging experiments at 3T and 7T. The image-guided RF calibration results in vitro were consistent with standard B0 and B1+ maps. The standard automated RF calibration procedure produced approximately 20% and 15–30% relative error in the transmit RF gain in the left kidney at 3T and brain at 7T, respectively. For initial application, a T2 mapping pulse sequence was applied at 7T. The T2 measurements in the thalamus at 7T were 60.6 ms and 48.2 ms using the standard and image-guided RF calibration procedures, respectively. This rapid, image-guided RF calibration procedure can be used to optimally calibrate the flip angle for a given ROI and thus minimize measurement errors for quantitative MRI and MR spectroscopy. PMID:20014333

Breton, Elodie; McGorty, KellyAnne; Wiggins, Graham C.; Axel, Leon; Kim, Daniel

2010-01-01

146

Nanogate - A Nanosecond Gated Image Intensifier with High Gain and High Resolution  

Microsoft Academic Search

The investigation of luminous phenomena with two-dimensional resolution in space and resolution in time requires electro-optical devices which can be gated for very short time intervals. Image intensifiers are presently mainly used for this purpose. They are available either as image intensifiers with microchannel plates or as image intensifier diodes. Due to secondary electron multiplication, microchannel plate intensifiers have high

W. Pfeiffer; D. Wittmer

1984-01-01

147

Fructose-induced leptin resistance exacerbates weight gain in response to subsequent high-fat feeding  

NSDL National Science Digital Library

It has been suggested that increased fructose intake is associated with obesity. We hypothesized that chronic fructose consumption causes leptin resistance, which subsequently may promote the development of obesity in response to a high fat diet. Sprague-Dawley rats were fed a fructose-free control or 60% fructose diet for six months and then tested for leptin resistance. Half of the rats in each group were then switched to high fat diet for two weeks, while the other half continued on their respective diets. Chronic fructose consumption caused leptin resistance while serum leptin levels, weight and adiposity were the same as in control rats that were leptin responsive. Intraperitoneal leptin injections reduced 24-hour food intake in fructose-free group (73.7 ñ 6.3 vs 58.1 ñ 8 kcal, p=0.02), but had no effect in fructose-fed rats (71.2 ñ 6.6 vs 72.4 ñ 6.4 kcal, p=0.9). Absence of anorexic response to intraperitoneal leptin injection was associated with 25.7% decrease in hypothalamic signal transducer and activator of transcription 3 (STAT3) phosphorylation in the high-fructose fed rats compared with controls (p=0.015). Subsequent exposure of the fructose-mediated leptin-resistant rats to a high fat diet lead to exacerbated weight gain (50.2 ñ 2 g) compared with correspondingly fed leptin-responsive animals that were pre-treated with the fructose-free diet (30.4 ñ 5.8 g, p= 0.012). Our data indicate that chronic fructose consumption induces leptin resistance prior to body weight, adiposity, serum leptin, insulin or glucose increases, and this fructose-induced leptin resistance accelerates high fat induced obesity

Alexandra Shapiro (University of Florida Pharmacology and Therapeutics); Wei Mu (University of Florida Nephrology); Carlos Roncal (University of Florida Nephrology); Kit-Yan Cheng (University of Florida Pharmacology/Therapeutics); MD Richard J Johnson (University of Florida Division of Nephrology); Philip Scarpace (University of Florida Pharmacology and Therapeutics)

2008-08-16

148

Coherent coupling and modified spontaneous emission of a single ion in a high finesse optical cavity  

NASA Astrophysics Data System (ADS)

thanksIn collaboration with A. Kreuter, A.B. Mundt, C. Russo, H. Häffner, C. Roos, J. Eschner, F. Schmidt-Kaler and R. Blatt, Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria. Laser-cooled trapped atoms or ions are ideally suited systems for storing and processing quantum information. The transport of this quantum information over large distances via photons requires an interface between atoms and photons (J.I. Cirac et al., Phys. Rev. Lett. 78, 3221 (1997)). Such an interface is based on the deterministic coherent coupling of a single atom or ion to macroscopic and vacuum fields inside a high finesse optical cavity. Here, we perform two experiments to investigate such an interaction of a single Ca^+ ion and a cavity field: first, we excite Rabi oscillations with short resonant laser pulses injected into the cavity, and second, we measure the modification of the spontaneous emission rate from the metastable D_5/2 level induced by the cavity-enhanced vacuum field. The ^40Ca^+ ion is stored in a spherical Paul trap placed in the center of a high finesse near-confocal resonator (Finesse approx. 30.000 at 729 nm). The ion is laser-cooled to the Lamb-Dicke regime, confining its spatial wave packet to a region much smaller than the optical wavelength. We stabilize the cavity to the S_1/2 - D_5/2 quadrupole transition frequency (wavelength: 729 nm) using a transfer lock technique (A.B. Mundt et al., Appl. Phys. B, in press). To demonstrate coherent coupling of the ion and a macroscopic cavity field, we inject resonant laser pulses of different pulse lengths at 729 nm into the cavity and record the excitation on the S_1/2 - D_5/2 transition via the electron shelving technique. We observe a Rabi oscillation frequency of up to 9 MHz when the ion is placed in a node of the cavity standing wave field. (Rabioscillations) For the measurement of the cavity modified spontaneous emission (Purcell effect), we repeat the following sequence for 1oo times: first, we excite the ion with a ?-pulse on the S_1/2 - D_5/2 transition. We then detect whether the excitation was successful (electron shelving), wait for a certain delay time and measure the D_5/2 population again. Every second experimental run, we shift the cavity by approx. 5 linewidths away from resonance. By repeating this procedure for many times we infer the spontaneous decay rate from the metastable level for the cavity on resonance and off resonance (equivalent to free space emission), thus excluding systematic errors due to environmental effects. For the free-space lifetime we measure a value of 1129(19) ms, close to the currently most precisely measured value of 1168 ms (P. Barton et al., Phys. Rev. A 62, 032503 (2000)). First experiments with a delay time of 90 ms show a lifetime reduction of approx. 10% on resonance. 78, l. Phys. B, in pr ess.

Becher, Christoph

2003-05-01

149

A novel 4H-SiC lateral bipolar junction transistor structure with high voltage and high current gain  

NASA Astrophysics Data System (ADS)

In this paper, a novel structure of a 4H-SiC lateral bipolar junction transistor (LBJT) with a base field plate and double RESURF in the drift region is presented. Collector-base junction depletion extension in the base region is restricted by the base field plate. Thin base as well as low base doping of the LBJT therefore can be achieved under the condition of avalanche breakdown. Simulation results show that thin base of 0.32 ?m and base doping of 3 × 1017 cm-3 are obtained, and corresponding current gain is as high as 247 with avalanche breakdown voltage of 3309 V when the drift region length is 30 ?m. Besides, an investigation of a 4H-SiC vertical BJT (VBJT) with comparable breakdown voltage (3357 V) shows that the minimum base width of 0.25 ?m and base doping as high as 8 × 1017 cm-3 contribute to a maximum current gain of only 128.

Deng, Yong-Hui; Xie, Gang; Wang, Tao; Sheng, Kuang

2013-09-01

150

Commensal E. coli Stx2 lysogens produce high levels of phages after spontaneous prophage induction  

PubMed Central

Enterohemorrhagic E. coli (EHEC) is a food-borne pathogen that causes disease ranging from uncomplicated diarrhea to life-threatening hemolytic uremic syndrome (HUS) and nervous system complications. Shiga toxin 2 (Stx2) is the major virulence factor of EHEC and is critical for development of HUS. The genes encoding Stx2 are carried by lambdoid bacteriophages and the toxin production is tightly linked to the production of phages during lytic cycle. It has previously been suggested that commensal E. coli could amplify the production of Stx2-phages and contribute to the severity of disease. In this study we examined the susceptibility of commensal E. coli strains to the Stx2-converting phage ?734, isolated from a highly virulent EHEC O103:H25 (NIPH-11060424). Among 38 commensal E. coli strains from healthy children below 5 years, 15 were lysogenized by the ?734 phage, whereas lytic infection was not observed. Three of the commensal E. coli ?734 lysogens were tested for stability, and appeared stable and retained the phage for at least 10 cultural passages. When induced to enter lytic cycle by H2O2 treatment, 8 out of 13 commensal lysogens produced more ?734 phages than NIPH-11060424. Strikingly, five of them even spontaneously (non-induced) produced higher levels of phage than the H2O2 induced NIPH-11060424. An especially high frequency of HUS (60%) was seen among children infected by NIPH-11060424 during the outbreak in 2006. Based on our findings, a high Stx2 production by commensal E. coli lysogens cannot be ruled out as a contributor to the high frequency of HUS during this outbreak.

Iversen, Hildegunn; L' Abée-Lund, Trine M.; Aspholm, Marina; Arnesen, Lotte P. S.; Lindbäck, Toril

2015-01-01

151

Nonclassical two-photon interferometry and lithography with high-gain parametric amplifiers  

Microsoft Academic Search

Optical parametric amplification is a process that leads to the generation of quantum states of light. In the limit of low single-pass gain, this process is often referred to as parametric down conversion, and produces entangled two-photon states. Such states have played a key role in recent studies of quantum optical effects such as quantum teleportation. As the gain of

Elna M. Nagasako; Sean J. Bentley; Robert W. Boyd; Girish S. Agarwal

2001-01-01

152

Defect controlled ultra high ultraviolet photocurrent gain in Cu-doped ZnO nanorod arrays: De-trapping yield  

NASA Astrophysics Data System (ADS)

Understanding the mechanism behind high photocurrent gain is very important to realize a highly functional material for photodetector devices. Herein, we report a very high ultraviolet photocurrent gain of 2.8 × 105 in hydrothermally grown Cu-doped ZnO nanorod arrays which is two orders of magnitude higher as compared to the undoped sample. Trapping of carriers under dark and de-trapping them under illumination by Cu-related defects is responsible for high gain. The trap state at ˜1.65 eV is attributed to the [{CuZn+(3d10)}- - Zni+(4s1)]0 type of defects. A model is shown to explain the dark and photocurrent states in the doped samples.

Sarkar, Sanjit; Basak, Durga

2013-07-01

153

High-gain AlGaAs/GaAs double heterojunction Darlington phototransistors for optical neural networks  

NASA Technical Reports Server (NTRS)

High-gain MOCVD-grown (metal-organic chemical vapor deposition) AlGaAs/GaAs/AlGaAs n-p-n double heterojunction bipolar transistors (DHBTs) and Darlington phototransistor pairs are provided for use in optical neural networks and other optoelectronic integrated circuit applications. The reduced base doping level used results in effective blockage of Zn out-diffusion, enabling a current gain of 500, higher than most previously reported values for Zn-diffused-base DHBTs. Darlington phototransitor pairs of this material can achieve a current gain of over 6000, which satisfies the gain requirement for optical neural network designs, which advantageously may employ neurons comprising the Darlington phototransistor pairs in series with a light source.

Kim, Jae H. (inventor); Lin, Steven H. (inventor)

1991-01-01

154

Design and performance of an Automatic Gain Control system for the High Energy X-Ray Timing Experiment  

NASA Technical Reports Server (NTRS)

The High Energy X-Ray Timing Experiment (HEXTE), currently under development for the X-Ray Timing Explorer (XTE) mission, employs a closed loop gain control system to attain 0.5 percent stabilization of each of eight-phoswich detector gains. This Automatic Gain Control (AGC) system utilizes a split window discriminator scheme to control the response of each detector pulse height analyzer to gated Am-241 X-ray events at 60 keV. A prototype AGC system has been implemented and tested within the gain perturbation environment expected to be experienced by the HEXTE instrument in flight. The AGC system and test configuration are described. Response, stability and noise characteristics are measured and compared with theoretical predictions. The system is found to be generally suitable for the HEXTE application.

Pelling, Michael R.; Rothschild, Richard E.; Macdonald, Daniel R.; Hertel, Robert; Nishiie, Edward

1991-01-01

155

Optical Amplifier with Flat-Gain and Wideband Operation Utilizing Highly Concentrated Erbium-Doped Fibers  

NASA Astrophysics Data System (ADS)

In this paper, we proposed a flat-gain and wide-band erbium doped fiber amplifier (EDFA) using two chirped fiber Bragg grating (CFBG) in serial configuration for double-pass operation. The amplifier consists of two sections of Erbium-doped fiber (EDF) operating in C-band and L-band respectively. A CFBG is used in each section to reflect the amplified signal back to the active area so that the overall gain spectrum can be enhanced and flattened. It is also observed that the gain of the amplifier produces a relatively higher gain with the Bismuth-based EDF (Bi-EDF) in the first stage compared to that of silica-based EDF (Si-EDF), especially in a longer wavelength region. The small signal gain of more than 19 dB is obtained within a wavelength region from 1545 to 1605 nm by the use of Bi-EDF with a small noise figure penalty. With a Si-EDF, the flat gain spectrum is observed within a wavelength region ranging from 1535 nm to 1605 nm with a gain variation of less than 2 dB at input signal of 0 dBm. This shows that the proposed serial double-pass amplifier may find its broad applications in wavelength division multiplexing long-haul systems as well as local optical networks.

Hamida, B. A.; Cheng, X. S.; Naji, A. W.; Ahmad, H.; Al-Khateeb, W.; Khan, S.; Harun, S. W.

156

Design parameters of the high gain harmonic generation experiment using Cornell Undulator A at the ATF  

SciTech Connect

The authors present the design parameters of a high gain harmonic generation (HGHG) FEL experiment to be carried out at the accelerator test facility (ATF) at BNL, in collaboration with APS. This experiment is a proof-of-principle experiment for the DUV-FEL at BNL. In the HGHG experiment the author plans to double the frequency of a CO{sub 2} seed layer by utilizing a 0.76 m long 9 period undulator (named the Mini Undulator), a 2 m long 60 period undulator (named the Cornell Undulator A), and a 0.3 m electromagnet chicane (the dispersive section). The first undulator will be used in conjunction with the CO{sub 2} seed laser to generate a ponderomotive force that will bunch the electron beam. The bunching will then be enhanced by the dispersion section. The second undulator, the Cornell Undulator A, tuned to the second harmonic of the seed laser will serve as the radiator. In the beginning of the radiator the bunched beam will produce coherent emission (characterized by a quadratic growth of the radiated power), then the radiation will be amplified exponentially. The author plans to study the evolution of the various radiation growth mechanisms as well as the coherence of the doubled, exponentially amplified radiation.

Yu, L.H. [Brookhaven National Lab., Upton, NY (United States)

1998-10-01

157

Case study of sample spacing in planar near-field measurement of high gain antennas  

NASA Technical Reports Server (NTRS)

Far field antenna patterns can be reconstructed from planar near field measurements acquired at a sample spacing of lambda/2 or less. For electrically large antennas, sampling at the Nyquist rate may result in errors due to system electronic drift over long acquisition times. The computer capacity may limit the largest size of the near field data set. The requirement to sample at the Nyquist rate is relaxed for high gain antennas which concentrate most of the radiated energy into a small angular region of the far field. The criteria for sample spacing at greater than lambda/e through the use of a priori information of the antenna radiation characteristics are presented. Far field patterns of a 30 GHz dual offset reflector system with a 2.7 m parabolic main reflector are computed from near field data obtained at sample spacings ranging from 0.1 lambda to 10 lambda. The effects of sampling interval and spectrum cutoff on the far field patterns are discussed.

Acosta, R. J.; Lee, R. Q.

1984-01-01

158

A Modified Lunar Reconnaissance Orbiter (LRO) High Gain Antenna (HGA) Controller Based on Flight Performance  

NASA Technical Reports Server (NTRS)

The National Aeronautics and Space Administration's (NASA) Lunar Reconnaissance Orbiter (LRO) was launched on June 18, 2009 and is currently in a 50 km mean altitude polar orbit around the Moon. LRO was designed and built by the NASA Goddard Space Flight Center in Greenbelt, MD. The spacecraft is three-axis stabilized via the attitude control system (ACS), which is composed of various control modes using different sets of sensors and actuators. In addition to pointing the spacecraft, the ACS is responsible for pointing LRO s two appendages, the Solar Array (SA) and the High Gain Antenna (HGA). This study reviews LRO s HGA control system. Starting with an overview of the HGA system, the paper delves into the single input single output (SISO) linear analysis followed by the controller design. Based on flight results, an alternate control scheme is devised to address inherent features in the flight control system. The modified control scheme couples the HGA loop with the spacecraft pointing control loop, and through analysis is shown to be stable and improve transient performance. Although proposed, the LRO project decided against implementing this modification.

Shah, Neerav

2010-01-01

159

Progress towards a high-gain and robust target design for heavy ion fusion  

NASA Astrophysics Data System (ADS)

Recently [E. Henestroza et al., Phys. Plasmas 18, 032702 (2011)], a new inertial-fusion target configuration, the X-target, using one-sided axial illumination has been explored. This class of target uses annular and solid-profile heavy ion beams to compress and ignite deuterium-tritium (DT) fuel that fills the interior of metal cases that have side-view cross sections in the shape of an "X." X-targets using all-DT-filled metal cases imploded by three annular ion beams resulted in fuel densities of ˜50 g/cm3 at peak compression, and fusion gains of ˜50, comparable to heavy ion driven hohlraum targets [D. A. Callahan-Miller and M. Tabak, Phys. Plasmas 7, 2083 (2000)]. This paper discusses updated X-target configurations that incorporate inside the case a propellant (plastic) and a pusher (aluminum) surrounding the DT fuel. The updated configurations are capable of assembling higher fuel areal densities ˜2 g/cm2 using two annular beams to implode the target to peak DT densities ˜100 g/cm3, followed by a fast-ignition solid ion beam which heats the high-density fuel to thermonuclear temperatures in ˜200 ps to start the burn propagation, obtaining gains of ˜300. These targets have been modeled using the radiation-hydrodynamics code HYDRA [M. M. Marinak et al., Phys. Plasmas 8, 2275 (2001)] in two- and three- dimensions to study the properties of the implosion as well as the ignition and burn propagation phases. At typical Eulerian mesh resolutions of a few microns, the aluminum-DT interface shows negligible Rayleigh-Taylor (RT) and Richtmyer-Meshkov instability growth; also, the shear flow of the DT fuel as it slides along the metal X-target walls, which drives the RT and Kelvin Helmholtz instabilities, does not have a major effect on the burning rate. An analytic estimate of the RT instability process at the Al-DT interface shows that the aluminum spikes generated during the pusher deceleration phase would not reach the ignition zone in time to affect the burning process. Also, preliminary HYDRA calculations, using a higher resolution mesh to study the shear flow of the DT fuel along the X-target walls, indicate that metal-mixed fuel produced near the walls would not be transferred to the DT ignition zone (at maximum ?R) located at the vertex of the X-target.

Henestroza, Enrique; Grant Logan, B.

2012-07-01

160

Progress towards a high-gain and robust target design for heavy ion fusion  

SciTech Connect

Recently [E. Henestroza et al., Phys. Plasmas 18, 032702 (2011)], a new inertial-fusion target configuration, the X-target, using one-sided axial illumination has been explored. This class of target uses annular and solid-profile heavy ion beams to compress and ignite deuterium-tritium (DT) fuel that fills the interior of metal cases that have side-view cross sections in the shape of an 'X.' X-targets using all-DT-filled metal cases imploded by three annular ion beams resulted in fuel densities of {approx}50 g/cm{sup 3} at peak compression, and fusion gains of {approx}50, comparable to heavy ion driven hohlraum targets [D. A. Callahan-Miller and M. Tabak, Phys. Plasmas 7, 2083 (2000)]. This paper discusses updated X-target configurations that incorporate inside the case a propellant (plastic) and a pusher (aluminum) surrounding the DT fuel. The updated configurations are capable of assembling higher fuel areal densities {approx}2 g/cm{sup 2} using two annular beams to implode the target to peak DT densities {approx}100 g/cm{sup 3}, followed by a fast-ignition solid ion beam which heats the high-density fuel to thermonuclear temperatures in {approx}200 ps to start the burn propagation, obtaining gains of {approx}300. These targets have been modeled using the radiation-hydrodynamics code HYDRA [M. M. Marinak et al., Phys. Plasmas 8, 2275 (2001)] in two- and three- dimensions to study the properties of the implosion as well as the ignition and burn propagation phases. At typical Eulerian mesh resolutions of a few microns, the aluminum-DT interface shows negligible Rayleigh-Taylor (RT) and Richtmyer-Meshkov instability growth; also, the shear flow of the DT fuel as it slides along the metal X-target walls, which drives the RT and Kelvin Helmholtz instabilities, does not have a major effect on the burning rate. An analytic estimate of the RT instability process at the Al-DT interface shows that the aluminum spikes generated during the pusher deceleration phase would not reach the ignition zone in time to affect the burning process. Also, preliminary HYDRA calculations, using a higher resolution mesh to study the shear flow of the DT fuel along the X-target walls, indicate that metal-mixed fuel produced near the walls would not be transferred to the DT ignition zone (at maximum {rho}R) located at the vertex of the X-target.

Henestroza, Enrique; Grant Logan, B. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2012-07-15

161

A High Gain, Composite Nd:YVO4/SiC Thin Disk Amplifier  

NASA Astrophysics Data System (ADS)

We have demonstrated a new form of Nd:YVO4 amplifier operating at 1064 nm based on a 800 µm thick Nd:YVO4 gain layer bonded to a 4H-SiC prism. The amplifier was tested in the `master oscillator - power amplifier' (MOPA) configuration, where both the seed source and the single pass amplifier were operated in a quasi-continuous wave (Q-CW) regime: pulse duration 500 µs, pulse repetition frequency (PRF) - 100 Hz. The Nd:YVO4gain element was pumped by a 808 nm laser diode bar stack to amplify seed inputs in the power range of 1 to 55 W with a gains of 4 to 2.6, respectively, with 25% optical-to-optical extraction efficiency. The temperature distribution of the gain medium was measured under operational conditions using thermography.

Newburgh, G. A.; Dubinskii, Mark

2014-06-01

162

Liver Fatty Acid Binding Protein Gene-ablation Exacerbates Weight Gain in High-Fat Fed Female Mice  

PubMed Central

Loss of liver fatty acid binding protein (L-FABP) decreases long chain fatty acid uptake and oxidation in primary hepatocytes and in vivo. On this basis, L-FABP gene ablation would potentiate high-fat diet-induced weight gain and weight gain/energy intake. While this was indeed the case when L-FABP null (?/?) mice on the C57BL/6NCr background were pair-fed high fat diet, whether this would also be observed under high-fat diet fed ad libitum was not known. Therefore, this possibility was examined in female L-FABP (?/?) mice on the same background. L-FABP (?/?) mice consumed equal amounts of defined high-fat or isocaloric control diets fed ad libitum. However, on the ad libitum fed high-fat diet the L-FABP (?/?) mice exhibited: 1) Decreased hepatic long chain fatty acid (LCFA) ?-oxidation as indicated by lower serum ?–hydroxybutyrate level; 2) Decreased hepatic protein levels of key enzymes mitochondrial (rate limiting carnitine palmitoyl acyltransferase A1, CPT1A; HMG-CoA synthase) and peroxisomal (acyl CoA oxidase 1, ACOX1) LCFA ?-oxidation; 3) Increased fat tissue mass (FTM) and FTM/energy intake to the greatest extent; and 4) Exacerbated body weight gain, weight gain/energy intake, liver weight, and liver weight/body weight to the greatest extent. Taken together, these findings showed that L-FABP gene-ablation exacerbated diet-induced weight gain and fat tissue mass gain in mice fed high-fat diet ad libitum—consistent with the known biochemistry and cell biology of L-FABP. PMID:23539345

McIntosh, Avery L.; Atshaves, Barbara P.; Landrock, Danilo; Landrock, Kerstin K.; Martin, Gregory G.; Storey, Stephen M.; Kier, Ann B.; Schroeder, Friedhelm

2013-01-01

163

Role of neutral base recombination in high gain AlGaAs\\/GaAs HBT's  

Microsoft Academic Search

Neutral base recombination is a limiting factor controlling the maximum gain of AlGaAs\\/GaAs HBT's with base sheet resistances between 100 and 350 ?\\/□. In this work, we investigate five series of AlGaAs\\/GaAs HBT growths in which the base thickness was varied between 500 and 1600 Å and the base doping level between 2.9× and 4.7×1019 cm-3. The dc current gain

Roger E. Welser; Noren Pan; Duy-Phach Vu; Peter J. Zampardi; Brian T. McDermott

1999-01-01

164

Parasitic oscillation suppression in high-gain solid-state amplifiers  

NASA Astrophysics Data System (ADS)

A method has been proposed for suppressing parasitic oscillation by processing the gain medium edges into arrises. The mode analysis indicates that the residual reflection at the gain medium edges decreases greatly and the required index matching level and the required cladding absorbency are reduced as well. With this method, a large choice of edge cladding material is allowed, which can help with avoiding distortion and other problems caused by thermal stress.

Zhang, Yongliang; Wei, Xiaofeng; Li, Mingzhong; Zheng, Jiangang; Zhang, Junwei; Xie, Na; Wang, Zhenguo; Wang, Mingzhe; Yan, Xiongwei; Jiang, Xinying

2013-05-01

165

Interval mapping of high growth (hg), a major locus that increases weight gain in mice  

SciTech Connect

The high growth locus (hg) causes a major increase in weight gain and body size in mice. As a first step to map-based cloning of hg, we developed a genetic map of the hg-containing region using interval mapping of 403 F{sub 2} from a C57BL/6J-hghg x CAST/EiJ cross. The maximum likelihood position of hg was at the chromosome 10 marker D10Mit41 (LOD = 24.8) in the F{sub 2} females and 1.5 cM distal to D10Mit41 (LOD = 9.56) in the F{sub 2} males with corresponding LOD 2 support intervals of 3.7 and 5.4 cM, respectively. The peak LOD scores were significantly higher than the estimated empirical threshold LOD values. The localization of hg by interval mapping was supported by a test cross of F{sub 2} mice recombinant between the LOD 2 support interval and the flanking marker. The interval mapping and test-cross indicate that hg is not allelic with candidate genes Igf1 or decorin (Dcn), a gene that was mapped close to hg in this study. The hg inheritance was recessive in females, although we could not reject recessive or additive inheritance in males. Possible causes for sex differences in peak LOD scores and for the distortion of transmission ratios observed in F{sub 2} males are discussed. The genetic map of the hg region will facilitate further fine mapping and cloning of hg, and allow searches for a homologous quantitative trait locus affecting growth in humans and domestic animals. 48 refs., 3 figs., 3 tabs.

Horvat, S.; Medrano, J.F. [Univ. of California, Davis, CA (United States)

1995-04-01

166

High mobility polymer based on a ?-extended benzodithiophene and its application for fast switching transistor and high gain photoconductor  

PubMed Central

Here we present synthesis and electronic properties of a new alternating copolymer composed of dithieno[2,3-d;2?,3?-d?]benzo[1,2-b;4,5-b?]dithiophene (DTBDT) and diketopyrrolopyrrole units, poly dithienobenzodithiophene-co-diketopyrrolopyrrolebithiophene (PDPDBD). The resulting polymer showed hysteresis free, fast switching and highly reliable organic thin-film transistor properties comparable to a-Si. Hole mobility of the polymer is about 2.7?cm2V?1s?1, which is remarkably improved compared with its benzodithiophene (BDT)-analougue that contains a smaller aromatic ring of BDT in the place of DTBDT. This is mainly due to much increased intramolecular charge transport originated from PDPDBD's rigid molecular backbone. Furthermore, photoconductor devices fabricated by using PDPDBD as an active layer showed a high performance with the highest photoconductive gain of ~105. Taken together, the successful PDPDBD's transistor and photoconductor performances with high device stability demonstrated practical applicability of PDPDBD in low-cost and flexible optoelectronic devices. PMID:24970637

Park, Sungmin; Lim, Byung Tack; Kim, BongSoo; Son, Hae Jung; Chung, Dae Sung

2014-01-01

167

Non-stoichiometric W18O49-xSx nanowires for wide spectrum photosensors with high internal gain  

NASA Astrophysics Data System (ADS)

This study reports successful synthesis of non-stoichiometric single-crystal W18O49-xSx nanowires for photosensors with a high absorption rate (>83%) across a wide spectrum (300-2000 nm), a high internal gain (G = 106-107) and a relatively fast response time (approximately 1-3 s). In addition, the correlation between the photoconductivity gain (G) and the surface-to-volume ratio of non-stoichiometric single-crystal W18O49-xSx nanowires was studied. The surface-to-volume ratio and non-stoichiometric material of W18O49-xSx contributed to the photoconductivity gain; hence, the nanowires are favorable for photosensor devices. The wide spectrum obtained also suggests their extensive applications in numerous fields.This study reports successful synthesis of non-stoichiometric single-crystal W18O49-xSx nanowires for photosensors with a high absorption rate (>83%) across a wide spectrum (300-2000 nm), a high internal gain (G = 106-107) and a relatively fast response time (approximately 1-3 s). In addition, the correlation between the photoconductivity gain (G) and the surface-to-volume ratio of non-stoichiometric single-crystal W18O49-xSx nanowires was studied. The surface-to-volume ratio and non-stoichiometric material of W18O49-xSx contributed to the photoconductivity gain; hence, the nanowires are favorable for photosensor devices. The wide spectrum obtained also suggests their extensive applications in numerous fields. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr05234j

Hsu, Yu-Ming; Wang, Chiu-Yen; Chang, Pin; Yew, Tri-Rung

2014-12-01

168

Prevention of high blood pressure by reducing sympathetic innervation in the spontaneously hypertensive rat  

Microsoft Academic Search

It has previously been reported that the increase in blood pressure in the spontaneously hypertensive rat (SHR) occurs concurrently with a marked increase in thickness of the arterial wall and an increase in vascular innervation, particularly for the small muscular arteries. The purpose of the present study was to determine whether prevention of the increase in vascular innervation could prevent

James A. Brock; Dirk F. Van Helden; Peter Dosen; Robert A. Rush

1996-01-01

169

Two-color operation in high-gain free-electron lasers  

PubMed

Two-color operation in free-electron laser (FEL) amplifiers is studied using a 3D nonlinear polychromatic simulation. We assume the FEL is seeded at two closely spaced wavelengths within the gain band, and study the growth of the seeds and a discrete spectrum of beat waves that are outside the gain band. The beat waves grow parasitically due to electron bunching in the seeded waves with growth rates higher than the seeded waves. Injection of narrow-band seeds ensures a discrete spectrum. An example is discussed corresponding to an x-ray FEL; however, the physics is applicable to all spectral ranges. PMID:11018961

Freund; O'Shea

2000-03-27

170

Design of a high gain single stage and single pass Nd:YVO4 passive picosecond amplifier  

E-print Network

); published August 7, 2012 A detailed comparison of the influence of pumping wavelength and crystal doping crystals and the importance of the crystal tem- perature for the design of a high gain amplifier. Using for only 50 mW of seed at 200 kHz in a single pass, single stage configuration. With a pulse duration of 22

171

Gain-scheduled Linear Quadratic Control of Wind Turbines Operating at High Wind Speed  

Microsoft Academic Search

This paper addresses state estimation and linear quadratic (LQ) control of variable speed variable pitch wind turbines. On the basis of a nonlinear model of a wind turbine, a set of operating conditions is identified and a LQ controller is designed for each operating point. The controller gains are then interpolated linearly to get a control law for the entire

K. Z. Ostergaard; Per Brath; Jakob Stoustrup

2007-01-01

172

High-temporal contrast using low-gain optical parametric amplification  

SciTech Connect

We demonstrate the use of low-gain optical parametric amplification (OPA) as a means of improving temporal contrast to a detection-limited level 10{sup -10}. 250 {mu}J, 500 fs pulses of 1053 nm are frequency doubled and subsequently restored to the original wavelength by OPA with >10% efficiency.

Shah, Rahul C [Los Alamos National Laboratory; Johnson, Randall P [Los Alamos National Laboratory; Shimada, Tsutomu [Los Alamos National Laboratory; Flippo, Kirk A [Los Alamos National Laboratory; Fernandez, Juan C [Los Alamos National Laboratory; Hegelich, Bjorn M [Los Alamos National Laboratory

2008-01-01

173

An ultra-low voltage high gain operational transconductance amplifier for biomedical  

E-print Network

Interface (ABCI) systems, insulin pumps, hearing aids and mobile communications require to develop circuits in [5]. In addition, a gate-driven amplifier with 0.5V rail-to-rail, 62dB DC gain and 75µW power dissipation is also proposed in [5]. Differential pairs are commonly used as input stages, in an ultra

Paris-Sud XI, Université de

174

Compact tunable high power picosecond source based on Yb-doped fiber amplification of gain switch laser diode.  

PubMed

A compact tunable high power picosecond source based on Yb-doped fiber amplification of gain switch laser diode is demonstrated. A multi-stage single mode Yb-doped fiber preamplifier was combined with a single mode double-clad Yb-doped fiber main amplifier to construct the amplification system, which is seeded by a gain switch laser diode. By optimizing preamplifier???s parameters to compensate the seed spectrum gain, a "flat top" broadband spectrum is obtained to realize wavelength tunable output with a self-made tunable filter. The tunable pulses were further amplified to 3.5 W average power 90 ps pulses at 1 MHz repetition rate, and the center wavelength was tunable in the ranges from 1053 nm to 1073 nm with excellent beam quality. PMID:18545499

Liu, Hongjun; Gao, Cunxiao; Tao, Jintao; Zhao, Wei; Wang, Yishan

2008-05-26

175

Wideband and flat-gain amplifier based on high concentration erbium-doped fibres in parallel double-pass configuration  

NASA Astrophysics Data System (ADS)

A wideband and flat gain erbium-doped fibre amplifier (EDFA) is demonstrated using a hybrid gain medium of a zirconiabased erbium-doped fibre (Zr-EDF) and a high concentration erbium-doped fibre (EDF). The amplifier has two stages comprising a 2-m-long ZEDF and 9-m-long EDF optimised for C- and L-band operations, respectively, in a double-pass parallel configuration. A chirp fibre Bragg grating (CFBG) is used in both stages to ensure double propagation of the signal and thus to increase the attainable gain in both C- and L-band regions. At an input signal power of 0 dBm, a flat gain of 15 dB is achieved with a gain variation of less than 0.5 dB within a wide wavelength range from 1530 to 1605 nm. The corresponding noise figure varies from 6.2 to 10.8 dB within this wavelength region.

Hamida, B. A.; Cheng, X. S.; Harun, S. W.; Naji, A. W.; Arof, H.; Al-Khateeb, W.; Khan, S.; Ahmad, H.

2012-03-01

176

Wideband and flat-gain amplifier based on high concentration erbium-doped fibres in parallel double-pass configuration  

SciTech Connect

A wideband and flat gain erbium-doped fibre amplifier (EDFA) is demonstrated using a hybrid gain medium of a zirconiabased erbium-doped fibre (Zr-EDF) and a high concentration erbium-doped fibre (EDF). The amplifier has two stages comprising a 2-m-long ZEDF and 9-m-long EDF optimised for C- and L-band operations, respectively, in a double-pass parallel configuration. A chirp fibre Bragg grating (CFBG) is used in both stages to ensure double propagation of the signal and thus to increase the attainable gain in both C- and L-band regions. At an input signal power of 0 dBm, a flat gain of 15 dB is achieved with a gain variation of less than 0.5 dB within a wide wavelength range from 1530 to 1605 nm. The corresponding noise figure varies from 6.2 to 10.8 dB within this wavelength region.

Hamida, B A; Cheng, X S; Harun, S W; Naji, A W; Arof, H; Al-Khateeb, W; Khan, S; Ahmad, H

2012-03-31

177

High-gain wide-band gyrotron traveling wave amplifier with a helically corrugated waveguide  

PubMed

First bandwidth measurements of a novel gyrotron amplifier are presented. The coupling between the second harmonic cyclotron mode of a gyrating electron beam and the radiation field occurred in the region of near infinite phase velocity over a broad bandwidth by using a cylindrical waveguide with a helical corrugation on its internal surface. With a beam energy of 185 keV, the amplifier achieved a maximum output power of 1.1 MW, saturated gain of 37 dB, linear gain of 47 dB, saturated bandwidth of 8.4 to 10.4 GHz ( 21% relative bandwidth), and an efficiency of 29%, in good agreement with theory. PMID:11017315

Bratman; Cross; Denisov; He; Phelps; Ronald; Samsonov; Whyte; Young

2000-03-20

178

A numerical algorithm for optimal feedback gains in high dimensional LQR problems  

NASA Technical Reports Server (NTRS)

A hybrid method for computing the feedback gains in linear quadratic regulator problems is proposed. The method, which combines the use of a Chandrasekhar type system with an iteration of the Newton-Kleinman form with variable acceleration parameter Smith schemes, is formulated so as to efficiently compute directly the feedback gains rather than solutions of an associated Riccati equation. The hybrid method is particularly appropriate when used with large dimensional systems such as those arising in approximating infinite dimensional (distributed parameter) control systems (e.g., those governed by delay-differential and partial differential equations). Computational advantage of the proposed algorithm over the standard eigenvector (Potter, Laub-Schur) based techniques are discussed and numerical evidence of the efficacy of our ideas presented.

Banks, H. T.; Ito, K.

1986-01-01

179

A High Gain and Broadband C-Band Aperture-Coupled Patch Antenna  

NASA Astrophysics Data System (ADS)

A aperture-coupled patch antenna is designed with parasitic elements connecting to the rectangle ring on the bottom of antenna substrate through metal vias, which lead the current induced by patch radiator to the top surface of antenna substrate. Therefore, the effective radiation is enhanced and higher gain is achieved. The bandwidth is broadened simultaneously due to the structure of aperture-coupled patch antenna with parasitic elements. Compared to the conventional aperture-coupled patch antenna, the antenna gain increases averagely 2 dB due to the novel structure. Compared to patch antenna of electromagnetic band-gap, the dimensions of novel patch antenna greatly decreases, which can be used as element in the array antenna. Two kinds manufactured antenna are both measured in an anechoic chamber. The good agreements between numerical simulation and experimental prototype have been obtained.

Liu, Chunheng; Lu, Yueguang; Du, Chunlei; Luo, Xiangang

2007-12-01

180

A numerical algorithm for optimal feedback gains in high dimensional linear quadratic regulator problems  

NASA Technical Reports Server (NTRS)

A hybrid method for computing the feedback gains in linear quadratic regulator problem is proposed. The method, which combines use of a Chandrasekhar type system with an iteration of the Newton-Kleinman form with variable acceleration parameter Smith schemes, is formulated to efficiently compute directly the feedback gains rather than solutions of an associated Riccati equation. The hybrid method is particularly appropriate when used with large dimensional systems such as those arising in approximating infinite-dimensional (distributed parameter) control systems (e.g., those governed by delay-differential and partial differential equations). Computational advantages of the proposed algorithm over the standard eigenvector (Potter, Laub-Schur) based techniques are discussed, and numerical evidence of the efficacy of these ideas is presented.

Banks, H. T.; Ito, K.

1991-01-01

181

High Gain, Fast Scan, Broad Spectrum, Parallel Beam Wavelength Dispersive X-ray Spectrometer for SEM  

SciTech Connect

Parallax Research, Inc. proposes to produce a new type of x-ray spectrometer for use with Scanning Electron Microscopy (SEM) that would have the energy resolution of WDS and the ease of use of EDS with sufficient gain for lower energies that it can be used at low beam currents as is EDS. Parallax proposes to do this by development of new multiple reflection x-ray collimation optics, new diffractor technology, new detector technology and new scan algorithms.

David OHara; Dr. Eric Lochmer

2003-09-12

182

High-gain step-profiled integrated diagonal horn-antennas  

Microsoft Academic Search

Dipole-excited integrated horn antennas are limited by their large flare angle of 70°, which is inherent in the anisotropic etching process of ?100? silicon wafers. The large flare angles does not allow for integrated horns with gain higher than 13 dB and for 10-dB beamwidths less than 90°. A step-profiled horn is proposed which reduces the effective flare angle of

George V. Eleftheriades; Gabriel M. Rebeiz

1992-01-01

183

A Low-Profile Compact Microwave Antenna With High Gain and Wide Bandwidth  

Microsoft Academic Search

We demonstrate a low-profile, compact antenna consisting of a cross dielectric resonator on a microstrip patch and a quasi-planar surface mounted short horn (SMSH). The measurements show a 10 dB return loss bandwidth from 6.07 GHz to 7.52 GHz (21.3%) and a gain better than 9.0 dBi over this bandwidth. The total height of the antenna is only 8.61 mm

Nasimuddin; Karu P. Esselle

2007-01-01

184

A leaky-wave analysis of the high-gain printed antenna configuration  

Microsoft Academic Search

A leaky-wave analysis is used to explain the narrow-beam resonance-gain phenomenon, in which narrow beams may be produced from a printed antenna element in a substrate-superstrate geometry. It is demonstrated that the phenomenon is attributable to the presence of both transverse electric and transverse magnetic-mode leaky waves that are excited on the structure. Asymptotic formulas for the leaky wave are

David R. Jackson; Arthur A. Oliner

1988-01-01

185

New wideband high-gain stripline planar array for 12 GHz satellite TV  

Microsoft Academic Search

A new type of stripline planar array has been studied for 12 GHz satellite TV reception. A 16-element experimental antenna (dimensions about 98 x 98 x 18 cu mm), using a stripline corporate feed, presents a 2:1 VSWR bandwidth of over 2 GHz and a gain higher than 20.6 dBi in the 11.7-12.5 GHz bandwidth.

E. Rammos

1982-01-01

186

A Deconvolution-Based Method with High Sensitivity and Temporal Resolution for Detection of Spontaneous Synaptic Currents In Vitro and In Vivo  

PubMed Central

Spontaneous postsynaptic currents (PSCs) provide key information about the mechanisms of synaptic transmission and the activity modes of neuronal networks. However, detecting spontaneous PSCs in vitro and in vivo has been challenging, because of the small amplitude, the variable kinetics, and the undefined time of generation of these events. Here, we describe a, to our knowledge, new method for detecting spontaneous synaptic events by deconvolution, using a template that approximates the average time course of spontaneous PSCs. A recorded PSC trace is deconvolved from the template, resulting in a series of delta-like functions. The maxima of these delta-like events are reliably detected, revealing the precise onset times of the spontaneous PSCs. Among all detection methods, the deconvolution-based method has a unique temporal resolution, allowing the detection of individual events in high-frequency bursts. Furthermore, the deconvolution-based method has a high amplitude resolution, because deconvolution can substantially increase the signal/noise ratio. When tested against previously published methods using experimental data, the deconvolution-based method was superior for spontaneous PSCs recorded in vivo. Using the high-resolution deconvolution-based detection algorithm, we show that the frequency of spontaneous excitatory postsynaptic currents in dentate gyrus granule cells is 4.5 times higher in vivo than in vitro. PMID:23062335

Pernía-Andrade, Alejandro Javier; Goswami, Sarit Pati; Stickler, Yvonne; Fröbe, Ulrich; Schlögl, Alois; Jonas, Peter

2012-01-01

187

Copy Number Gains in 11q13 and 8q34 Are Highly Linked to Prognosis in Cutaneous Malignant Melanoma  

PubMed Central

Relating specific genetic alterations to prognosis may help improve prognostication in melanoma, may identify key oncogenic drivers in cancer, and may assist in developing targeted therapies. Characteristic genetic alterations in melanoma include chromosomal copy number aberrations. We evaluated 97 melanomas (55 metastasizing and 42 nonmetastasizing) after a minimum 5-year follow-up in a case-control study using fluorescence in situ hybridization, targeting commonly altered chromosomal loci in melanoma. Eight probes arranged in two panels were used, and 11 parameters were evaluated. Parameters showing a statistically significant difference between the metastasizing and nonmetastasizing groups were evaluated with multivariate logistic regression analysis to compare their prognostic potential with other traditional prognostic markers used by the American Joint Committee on Cancer. Four of 11 parameters evaluated, including CCND1 (alias Bcl-1) gain, CCND1 r-gain, MYC (alias c-myc) gain, and MYC r-gain, had a statistically significant difference in the metastasizing versus nonmetastasizing group. All four parameters maintained statistical significance when evaluated in separate multivariate logistic regression analyses that included the seven currently used American Joint Commission on Cancer prognosticators in melanoma. In multivariate analyses, these four parameters were second only to ulceration in their prognostic potential. Copy number changes at 11q13 and 8q34 harboring CCND1 and MYC, respectively, are highly associated with prognosis. Fluorescence in situ hybridization targeting these loci may be a useful standardized prognostic marker in melanoma skin cancer. PMID:21497295

Gerami, Pedram; Jewell, Susan S.; Pouryazdanparast, Pedram; Wayne, Jeffery D.; Haghighat, Zahra; Busam, Klaus J.; Rademaker, Alfred; Morrison, Larry

2011-01-01

188

High magnetic shear gain in a liquid sodium stable couette flow experiment A prelude to an alpha - omega dynamo  

SciTech Connect

The {Omega}-phase of the liquid sodium {alpha}-{Omega} dynamo experiment at NMIMT in cooperation with LANL has successfully demonstrated the production of a high toroidal field, B{sub {phi}} {approx_equal} 8 x B{sub r} from the radial component of an applied poloidal magnetic field, B{sub r}. This enhanced toroidal field is produced by rotational shear in stable Couette Row within liquid sodium at Rm {approx_equal} 120. The small turbulence in stable Taylor-Couette Row is caused by Ekman Row where ({delta}v/v){sup 2} {approx} 10{sup -3}. This high {Omega}-gain in low turbulence flow contrasts with a smaller {Omega}-gain in higher turbulence, Helmholtz-unstable shear flows. This result supports the ansatz that large scale astrophysical magnetic fields are created within semi-coherent large scale motions in which turbulence plays a diffusive role that enables magnetic flux linkage.

Colgate, Stirling [Los Alamos National Laboratory; Li, Jui [Los Alamos National Laboratory; Finn, John [Los Alamos National Laboratory; Pariev, Vladimir [Los Alamos National Laboratory; Beckley, Howard [NM INSTIT. OF MINING AND TECH; Si, Jiahe [NM INSTIT. OF MINING AND TECH.; Martinic, Joe [NM INSTIT. OF MINING AND TECH.; Westpfahl, David [NM INSTIT. OF TECH.; Slutz, James [NM INSTIT. OF MINING AND TECH.; Westrom, Zeb [NM INSTIT. OF TECH.; Klein, Brianna [NM INSTIT. OF MINING AND TECH.

2010-11-08

189

Operation of proportional counters under high gas gain, high working gas pressure in mixed field of radiation  

NASA Astrophysics Data System (ADS)

It was noted that gas gain depends on type of detected radiation and for beta particle is higher by 6-8 % than for X-ray . Over some value of current flowing through the counter (IC-critical current) the reduction in gas gain due to space charge defined by the time of evacuation of positive ions is observed. The value of IC for different counter geometries and different mixture pressures was measured. It limits the rate capability of the detector for fixed gas gain. Over some value of gas gain (AC-critical value of gas gain) non-proportionality due to self inducted space charge effect is observed. The value of AC was measured as a function of working gas pressure for different counter geometries. Measurements were made for gas compositions Ar+20% CO2 and Ar+6.4% CO2+2.5% N2, for mixture pressures from 0.05 to 0.65 MPa and for different counter geometries.

Koperny, Stefan; Kowalski, Tadeusz Z.

2013-08-01

190

Plasmonic Amplification with Ultra-High Optical Gain at Room Temperature  

PubMed Central

Nanoplasmonic devices are promising for next generation information and communication technologies because of their capability to confine light at subwavelength scale and transport signals with ultrahigh speeds. However, ohmic losses are inherent to all plasmonic devices so that further development of integrated plasmonics requires efficient in situ loss compensation of signals with a wavelength and polarization of choice. Here we show that CdSe nanobelt/Al2O3/Ag hybrid plasmonic waveguides allow for efficient broadband loss compensation of propagating hybrid plasmonic signals of different polarizations using an optical pump and probe technique. With an internal gain coefficient of 6755?cm?1 at ambient condition, almost 100% of the propagation loss of TM-dominant plasmonic signals is compensated. From comparison with a similar photonic structure we attribute the fast-increasing gain at low pump intensity in hybrid plasmonic waveguides to the transfer across the metal-oxide-semiconductor interface of ‘hot' electrons photogenerated by the pump light. PMID:23752666

Liu, Ning; Wei, Hong; Li, Jing; Wang, Zhuoxian; Tian, Xiaorui; Pan, Anlian; Xu, Hongxing

2013-01-01

191

Bremsstrahlung emission of high energy accompanying spontaneous fission of {sup 252}Cf  

SciTech Connect

The study of the bremsstrahlung photon emission accompanying fragments produced in the spontaneous fission of heavy nuclei by a fully quantum approach is presented for the first time. This kind of problem requires the knowledge of wave functions of the fissioning system leading to a wide distribution of couples of fragments that are the products of fission. With the aim of obtaining these wave functions, the interaction potential between the emitted fragment and residual nucleus is calculated by a standard approach. A new procedure was performed that allows an increase in the accuracy of calculations of radial integrals in the far asymptotic region and the achievement of the convenient convergence in calculations of the spectra. The total probability of the emitted photons in the spontaneous fission of {sup 252}Cf was calculated in such a way. We obtained good agreement between theory and experimental data up to 38 MeV for the bremsstrahlung spectrum of photons while the calculation of the total probability of photon emission accompanying fragments was performed up to an energy of 60 MeV. The analysis of contributions in the bremsstrahlung spectrum accompanying the emission of light, medium, and heavy fragments in the fission of {sup 252}Cf is presented.

Maydanyuk, S. P.; Olkhovsky, V. S.; Mandaglio, G.; Manganaro, M.; Fazio, G.; Giardina, G. [Institute for Nuclear Research, National Academy of Science of Ukraine, Kiev 03680 (Ukraine); Dipartimento di Fisica dell'Universita di Messina, I-98166 Messina (Italy) and Istituto Nazionale di Fisica Nucleare, Sezione di Catania, I-95123 Catania (Italy)

2010-07-15

192

Early programming of weight gain in mice prevents the induction of obesity by a highly palatable diet.  

PubMed

Poor early growth is associated with Type II diabetes, hypertension and other features of the metabolic syndrome in adulthood. It has been suggested that this results from the development of a thrifty phenotype by a malnourished fetus. Such a phenotype would predispose the offspring to the development of obesity if born into conditions of over-nutrition. The present study aimed to determine if early nutrition affected subsequent development of obesity. Mice were established as follows: (a) controls (offspring of control dams), (b) recuperated (offspring of dams fed a low-protein diet during pregnancy, but nursed by control dams) and (c) postnatal low-protein (offspring of control dams nursed by low-protein-fed dams). Mice were weaned on to standard laboratory chow or a cafeteria diet. Recuperated offspring, although smaller at birth ( P <0.01), caught up and exceeded the weight of control offspring by 7 days of age ( P <0.001). Postnatal low-protein offspring were smaller than controls by 7 days of age ( P <0.001). Recuperated animals gained more weight than controls when given free access to a highly palatable diet ( P <0.01). Postnatal low-protein animals showed no additional weight gain when given a highly palatable diet compared with chow-fed litter-mates. These results suggest that the early environment has long-term consequences for weight gain. These programmed responses are powerful enough to block excess weight gain from a highly palatable diet and, thus, have major implications for the drug-free regulation of food intake and obesity. PMID:14507258

Ozanne, Susan E; Lewis, Rohan; Jennings, Bridget J; Hales, C Nicholas

2004-02-01

193

High-gain amplification in Yb:CaF2 crystals pumped by a high-brightness Yb-doped 976 nm fiber laser  

NASA Astrophysics Data System (ADS)

We report on high single-pass gain in Yb:CaF2 crystal longitudinally pumped with a 40 W high-brightness fiber laser source based on an ytterbium-doped ultra-large core photonic crystal rod-type fiber operating at 976 nm. A single-pass small-signal gain of 3.2 has been achieved in a 6 % Yb-doped 10-mm-long CaF2 crystal at room temperature, outperforming any CW-diode-pumped scheme and paving the way towards very promising innovative lasers and amplifiers schemes merging the Yb-doped solid-state and fiber technologies.

Machinet, G.; Andriukaitis, G.; Sévillano, P.; Lhermite, J.; Descamps, D.; Pugžlys, A.; Baltuška, A.; Cormier, E.

2013-05-01

194

High-gain step-profiled integrated diagonal horn-antennas  

NASA Technical Reports Server (NTRS)

A new step-profiled integrated-horn antenna is proposed. The antenna allows gains in the range of 17-20 dB to be achieved using standard (100) silicon wafers. The antenna is diagonally fed and exhibits very good circular symmetry within the 10-dB beamwidth. It has a fundamental Gaussian coupling efficiency of 83 percent. It is demonstrated that the profiled antenna has a radiation pattern similar to that of its smooth envelope horn, provided that the discontinuity between successive wafers does not exceed 0.15 lambda. The integrated stepped-profile horn performs much better than a corresponding smooth 70 deg flare-angle integrated horn of the same aperture size. The integrated step-profile horn is very well-suited for radio-astonomical and remote-sensing millimeter-wave imaging arrays requiring a large number of focal-plane elements.

Eleftheriades, George V.; Rebeiz, Gabriel M.

1992-01-01

195

Sustained mild hypergravity reduces spontaneous cardiac baroreflex sensitivity.  

PubMed

Head-to-foot gravitational force >1G (+Gz hypergravity) augments venous pooling in the lower body and reduces central blood volume during exposure, compared with 1Gz. Central hypovolemia has been reported to reduce spontaneous cardiac baroreflex sensitivity. However, no investigations have examined spontaneous cardiac baroreflex sensitivity during exposure to sustained mild +Gz hypergravity. We therefore hypothesized that mild +Gz hypergravity would reduce spontaneous cardiac baroreflex sensitivity, compared with 1Gz. To test this hypothesis, we examined spontaneous cardiac baroreflex sensitivity in 16 healthy men during exposure to mild +Gz hypergravity using a short-arm centrifuge. Beat-to-beat arterial blood pressure (tonometry) and R-R interval (electrocardiography) were obtained during 1Gz and 1.5Gz exposures. Spontaneous cardiac baroreflex sensitivity was assessed by sequence slope and transfer function gain. Stroke volume was calculated from the arterial pressure waveform using a three-element model. All indices of spontaneous cardiac baroreflex sensitivity decreased significantly (up slope: 18.6±2.3?12.7±1.6ms/mmHg, P<0.001; down slope: 19.0±2.5?13.2±1.3ms/mmHg, P=0.002; transfer function gain in low frequency: 14.4±2.2?10.1±1.1ms/mmHg, P=0.004; transfer function gain in high frequency: 22.2±7.5?12.4±3.5ms/mmHg, P<0.001). Stroke volume decreased significantly (88±5?80±6ml, P=0.025). Moreover, although systolic arterial pressure variability increased, R-R interval variability did not increase. These results suggest that even mild +Gz hypergravity reduces spontaneous cardiac baroreflex sensitivity, increasing the risk of cardiovascular disturbance during the exposure. PMID:25156804

Yanagida, Ryo; Ogawa, Yojiro; Ueda, Kaname; Aoki, Ken; Iwasaki, Ken-ichi

2014-10-01

196

Regrowth-free high-gain InGaAsP/InP active-passive platform via ion implantation.  

PubMed

We demonstrate a regrowth-free material platform to create monolithic InGaAsP/InP photonic integrated circuits (PICs) with high-gain active and low-loss passive sections via a PL detuning of >135 nm. We show 2.5 µm wide by 400 µm long semiconductor optical amplifiers with >40 dB/mm gain at 1570 nm, and passive waveguide losses <2.3 dB/mm. The bandgap in the passive section is detuned using low-energy 190 keV channelized phosphorous implantation and subsequent rapid thermal annealing to achieve impurity-induced quantum well intermixing (QWI). The PL wavelengths in the active and passive sections are 1553 and 1417 nm, respectively. Lasing wavelengths for 500 µm Fabry-Perot lasers are 1567 and 1453 nm, respectively. PMID:23037047

Parker, John S; Sivananthan, Abirami; Norberg, Erik; Coldren, Larry A

2012-08-27

197

Eigenmode analysis of a high-gain free-electron laser based on a transverse gradient undulator  

NASA Astrophysics Data System (ADS)

The use of a transverse gradient undulator (TGU) is viewed as an attractive option for free-electron lasers (FELs) driven by beams with a large energy spread. By suitably dispersing the electron beam and tilting the undulator poles, the energy spread effect can be substantially mitigated. However, adding the dispersion typically leads to electron beams with large aspect ratios. As a result, the presence of higher-order modes in the FEL radiation can become significant. To investigate this effect, we study the eigenmode properties of a TGU-based, high-gain FEL, using both an analytically-solvable model and a variational technique. Our analysis, which includes the fundamental and the higher-order FEL eigenmodes, can provide an estimate of the mode content for the output radiation. This formalism also enables us to study the trade-off between FEL gain and transverse coherence. Numerical results are presented for a representative soft X-ray, TGU FEL example.

Baxevanis, Panagiotis; Huang, Zhirong; Ruth, Ronald; Schroeder, Carl B.

2015-01-01

198

Detection of spontaneous class-specific visual stimuli with high temporal accuracy in human electrocorticography.  

PubMed

Most brain-computer interface classification experiments from electrical potential recordings have been focused on the identification of classes of stimuli or behavior where the timing of experimental parameters is known or pre-designated. Real world experience, however, is spontaneous, and to this end we describe an experiment predicting the occurrence, timing, and types of visual stimuli perceived by a human subject from electrocorticographic recordings. All 300 of 300 presented stimuli were correctly detected, with a temporal precision of order 20 ms. The type of stimulus (face/house) was correctly identified in 95% of these cases. There were approximately 20 false alarm events, corresponding to a late 2nd neuronal response to a previously identified event. PMID:19964434

Miller, Kai J; Hermes, Dora; Schalk, Gerwin; Ramsey, Nick F; Jagadeesh, Bharathi; den Nijs, Marcel; Ojemann, Jeffrey G; Rao, Rajesh P N

2009-01-01

199

Renalase mRNA levels in the brain, heart, and kidneys of spontaneously hypertensive rats with moderate and high hypertension  

PubMed Central

Background Renalase is a recently discovered secretory protein involved in regulation of arterial blood pressure in humans and animals. Results of animal experiments from independent laboratories indicate that administration of human recombinant renalase decreases blood pressure and some genetically predisposed hypertensive rats have lowered renalase levels. Material/Methods The levels of renalase mRNA expression in brain hemispheres, heart, and kidneys of spontaneously hypertensive rats (SHR) with moderate (140–180 mm Hg) or high (>180 mm Hg) hypertension and of control Wistar-Kyoto (WKY) rats were analyzed using real-time PCR. Results Spontaneously hypertensive rats with high hypertension (>180 mm Hg) had a lower renalase mRNA level in brain hemispheres, and higher heart and kidney renalase mRNA levels compared with control WKY rats. In SHR with a moderate increase in arterial blood pressure (140–180 mm Hg), the tissue renalase mRNA changed in the same direction but did not reach the level of statistical significance as compared with control rats. Conclusions The results indicate that the development of hypertension in SHR is accompanied by altered expression of the renalase gene in the examined organs as compared with control WKY rats. The brain and peripheral tissues renalase mRNA levels demonstrate opposite trends, which are obviously crucial for impaired regulation of blood pressure in SHR. PMID:24113803

Fedchenko, Valerii; Globa, Alexander; Buneeva, Olga; Medvedev, Alexei

2013-01-01

200

Gain coupling of class A semiconductor lasers.  

PubMed

We report on the development of a gain-coupled class A semiconductor laser for dual-wavelength generation via optical switching. A vertical external cavity surface emitting laser (VECSEL) structure is used, because it provides a flexible platform for high-power, high-brightness output in the near-IR and visible ranges. For the first time (to our knowledge), two VECSEL cavities sharing a common gain region are studied. Because the cavities are in competition for common carriers, birefringent filters in the external cavity control the laser cavity thresholds; this configuration demonstrates the possibility of switching between the two cavities, which can operate at different wavelengths. However, in this Letter we also show, numerically and experimentally, that with the consideration of spontaneous emission, it is possible to maintain simultaneous lasing in each cavity at a different wavelength. PMID:20847778

Hessenius, Chris; Terry, Nathan; Fallahi, Mahmoud; Moloney, Jerome; Bedford, Robert

2010-09-15

201

Surface plasmon resonance-induced color-selective Au-peapodded silica nanowire photodetectors with high photoconductive gain  

NASA Astrophysics Data System (ADS)

We report the optoelectronic device properties of individual Au-silica hybrid nanowires prepared by microwave plasma enhanced chemical vapor deposition. Due to the surface plasmon resonance (SPR) effect the photo-responsivity peak strongly depends on the shape of the embedded gold nanostructures in the silica nanowire in which the shape can be modified by controlling the growth time of Au-silica nanowires. Finite difference time domain (FDTD) simulation shows that the electric field distribution profiles of Au-silica hybrid nanowires support the photo-responsivity spectrum results. The photodetector performance of the Au-NPs@silica nanowire is investigated. The single Au-NPs@silica nanowire exhibits unique photo-responsivity in the visible range (500 nm), high selectivity, high photoconductive gain, and very fast rise (141 ?s) and decay (298 ?s) time constants. Furthermore, the mechanism for the high photoconductive gain is also discussed. This result implies that the Au-NPs@silica nanowire can be applied for future nanoscale optoelectronic devices.We report the optoelectronic device properties of individual Au-silica hybrid nanowires prepared by microwave plasma enhanced chemical vapor deposition. Due to the surface plasmon resonance (SPR) effect the photo-responsivity peak strongly depends on the shape of the embedded gold nanostructures in the silica nanowire in which the shape can be modified by controlling the growth time of Au-silica nanowires. Finite difference time domain (FDTD) simulation shows that the electric field distribution profiles of Au-silica hybrid nanowires support the photo-responsivity spectrum results. The photodetector performance of the Au-NPs@silica nanowire is investigated. The single Au-NPs@silica nanowire exhibits unique photo-responsivity in the visible range (500 nm), high selectivity, high photoconductive gain, and very fast rise (141 ?s) and decay (298 ?s) time constants. Furthermore, the mechanism for the high photoconductive gain is also discussed. This result implies that the Au-NPs@silica nanowire can be applied for future nanoscale optoelectronic devices. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr04533a

Wang, Sheng-Bo; Chen, Ruei-San; Chang, Shoou Jinn; Han, Hsieh-Cheng; Hu, Ming-Shien; Chen, Kuei-Hsien; Chen, Li-Chyong

2014-01-01

202

Very High Energy Gain at the Neptune Inverse Free Electron Laser Experiment  

SciTech Connect

We report the observation of energy gain in excess of 20 MeV at the Inverse Free Electron Laser Accelerator experiment at the Neptune Laboratory at UCLA. A 14.5 MeV electron beam is injected in an undulator strongly tapered in period and field amplitude. The IFEL driver is a CO2 10.6 {mu}m laser with power larger than 400 GW. The Rayleigh range of the laser, {approx} 1.8 cm, is much shorter than the undulator length so that the interaction is diffraction dominated. A few per cent of the injected particles are trapped in a stable accelerating bucket. Electrons with energies up to 35 MeV are measured by a magnetic spectrometer. Three-dimensional simulations, in good agreement with the measured electron energy spectrum, indicate that most of the acceleration occurs in the first 25 cm of the undulator, corresponding to an energy gradient larger than 70 MeV/m. The measured energy spectrum also indicates that higher harmonic Inverse Free Electron Laser interaction takes place in the second section of the undulator.

Musumeci, P.; Boucher, S.; Doyuran, A.; England, R. J.; Pellegrini, C.; Rosenzweig, J. B.; Travish, G.; Yoder, R. [Neptune Laboratory Department of Physics and Astronomy, University of California, Los Angeles, CA, 90095 (United States); Tochitsky, S.Ya.; Joshi, C.; Ralph, J.; Sung, C. [Department of Electrical Engineering. University of California, Los Angeles, CA, 90095 (United States); Tolmachev, S.; Varfolomeev, A.; Varfolomeev, A. Jr.; Yarovoi, T. [RRCKI, Moscow (Russian Federation)

2004-12-07

203

A high speed and high gain CMOS receiver chip for a pulsed time-of-flight laser rangefinder  

NASA Astrophysics Data System (ADS)

An integrated receiver channel for a pulsed time-of-flight (TOF) laser rangefinder has been designed. Pulsed TOF laser range finding devices using a laser diode transmitter can achieve millimeter-level distance measurement accuracy in a measurement range of several tens of meters to non-cooperative targets. The amplifier exploits the regulated cascade (RGC) configuration as the input-stage, thus achieving as large effective input trans-conductance as that of Si Bipolar or GaAs MESFET. The RGC input configuration isolates the input parasitic capacitance including photodiode capacitance from the bandwidth determination better than common-gate TIA. To enlarge the bandwidth, inductive peaking technology has been adopted. An active inductor (MOS-L) is used instead of spiral inductor in CMOS process. An R-2R resistor ladder is inserting between per-amplifier and post-amplifier as the variable attenuator for digital gain control purpose. The gain-bandwidth of a basic differential pair with resistive load is not large enough for broad band operation. A circuit solution to improve both gain and bandwidth of an amplifying stage is proposed. Traditional and modified Cherry-Hooper amplifiers are discussed and the cascading of several stages to constitute the post-amplifier is designed. The fully integrated one-chip solution is designed with Cadence IC design platform. The simulation result shows the bandwidth of the trans-impedance amplifier is 215MHz with the presence of a 2pF input capacitor and 5pF load capacitor. And the maximum trans-impedance gain is 136dB. The walk error is less than 1ns in 1:1000 dynamic range. The responsive time is less than 2.2ns.

Yu, Jin-jin; Deng, Ruo-han; Yuan, Hong-hui; Chen, Yong-ping

2011-06-01

204

Shuttle orbiter Ku-band radar/communications system design evaluation: High gain antenna/widebeam horn  

NASA Technical Reports Server (NTRS)

The physical characteristics of the high gain antenna reflector and feed elements are described. Deficiencies in the sum feed are discussed, and lack of atmospheric venting is posed as a potential problem area. The measured RF performance of the high gain antenna is examined and the high sidelobe levels measured are related to the physical characteristics of the antenna. An examination of the attributes of the feed which might be influenced by temperature extremes shows that the antenna should be insensitive to temperature variations. Because the feed support bipod structure is considered a significant contributor to the high sidelobe levels measured in the azimuth plane, pod relocation, material changes, and shaping are suggested as improvements. Alternate feed designs are presented to further improve system performance. The widebeam horn and potential temperature effects due to the polarizer are discussed as well as in the effects of linear polarization on TDRS acquisition, and the effects of circular polarization on radar sidelobe avoidance. The radar detection probability is analyzed as a function of scan overlap and target range.

Iwasaki, R.; Dodds, J. G.; Broad, P.

1979-01-01

205

Transverse and temporal characteristics of a high-gain free-electron laser in the saturation regime  

NASA Astrophysics Data System (ADS)

The transverse and the temporal characteristics of a high-gain free-electron laser are governed by refractive guiding and sideband instability, respectively. Using the self-consistent Vlasov-Maxwell equations, we explicitly determine the effective index of refraction and the guided radiation mode for an electron beam with arbitrary transverse size. Electrons trapped by the guided radiation execute synchrotron oscillation and hence are susceptible to the sideband instability. We explain the spectral evolution and determine the sideband growth rate. These theoretical predictions agree well with GINGER simulation results.

Huang, Zhirong; Kim, Kwang-Je

2002-05-01

206

High-Resolution Mapping of Two Types of Spontaneous Mitotic Gene Conversion Events in Saccharomyces cerevisiae  

PubMed Central

Gene conversions and crossovers are related products of the repair of double-stranded DNA breaks by homologous recombination. Most previous studies of mitotic gene conversion events have been restricted to measuring conversion tracts that are <5 kb. Using a genetic assay in which the lengths of very long gene conversion tracts can be measured, we detected two types of conversions: those with a median size of ?6 kb and those with a median size of >50 kb. The unusually long tracts are initiated at a naturally occurring recombination hotspot formed by two inverted Ty elements. We suggest that these long gene conversion events may be generated by a mechanism (break-induced replication or repair of a double-stranded DNA gap) different from the short conversion tracts that likely reflect heteroduplex formation followed by DNA mismatch repair. Both the short and long mitotic conversion tracts are considerably longer than those observed in meiosis. Since mitotic crossovers in a diploid can result in a heterozygous recessive deleterious mutation becoming homozygous, it has been suggested that the repair of DNA breaks by mitotic recombination involves gene conversion events that are unassociated with crossing over. In contrast to this prediction, we found that ?40% of the conversion tracts are associated with crossovers. Spontaneous mitotic crossover events in yeast are frequent enough to be an important factor in genome evolution. PMID:24990991

Yim, Eunice; O’Connell, Karen E.; St. Charles, Jordan; Petes, Thomas D.

2014-01-01

207

High gain, low noise, fully complementary logic inverter based on bi-layer WSe2 field effect transistors  

NASA Astrophysics Data System (ADS)

In this article, first, we show that by contact work function engineering, electrostatic doping and proper scaling of both the oxide thickness and the flake thickness, high performance p- and n-type WSe2 field effect transistors (FETs) can be realized. We report record high drive current of 98 ?A/?m for the electron conduction and 110 ?A/?m for the hole conduction in Schottky barrier WSe2 FETs. Then, we combine high performance WSe2 PFET with WSe2 NFET in double gated transistor geometry to demonstrate a fully complementary logic inverter. We also show that by adjusting the threshold voltages for the NFET and the PFET, the gain and the noise margin of the inverter can be significantly enhanced. The maximum gain of our chemical doping free WSe2 inverter was found to be ˜25 and the noise margin was close to its ideal value of ˜2.5 V for a supply voltage of VDD = 5.0 V.

Das, Saptarshi; Dubey, Madan; Roelofs, Andreas

2014-08-01

208

Evolution of electron beam phase space distribution in a high-gain FEL  

SciTech Connect

FEL-based coherent electron cooling (CEC) offers a new avenue to achieve high luminosities in high energy colliders such as RHIC, LHC, and eRHIC. Traditional treatments consider the FEL as an amplifier of optical waves with specific initial conditions, focusing on the resulting field. CEC requires knowledge of the phase space distribution of the electron beam in the FEL. We present 1D analytical results for the phase space distribution of an electron beam with an arbitrary initial current profile, and discuss approaches of expanding to 3D results.

Webb,S.D.; Litvinenko, V. N.

2009-08-23

209

A Critical Examination of the Evidence Relating High Fructose Corn Syrup and Weight Gain  

Microsoft Academic Search

The use of high fructose corn syrup (HFCS) has increased over the past several decades in the United States while overweight and obesity rates have risen dramatically. Some scientists hypothesize that HFCS consumption has uniquely contributed to the increasing mean body mass index (BMI) of the U.S. population. The Center for Food, Nutrition, and Agriculture Policy convened an expert panel

Richard A. Forshee; Maureen L. Storey; David B. Allison; Walter H. Glinsmann; Gayle L. Hein; David R. Lineback; Sanford A. Miller; Theresa A. Nicklas; Gary A. Weaver; John S. White

2007-01-01

210

High-Speed Switched-Capacitor Filters Based On Unity-Gain Buffers David Bruneau  

E-print Network

-Ku Moon for providing guidance and setting the bar high. Thanks to Dr. G´abor Temes, Dr. Andreas Weisshaar.2.2 Modified LCR Prototype . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 3.2.3 S-Domain State Equations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 3.2.4 S-to-Z Domain Transformation

Moon, Un-Ku

211

A Current Balancing Instrumentation Amplifier (CBIA) Bioamplifier with High Gain Accuracy  

E-print Network

. In addition it uses common circuit design techniques such as chopper modulation to achieve low flicker noise corner frequency, high common mode rejection (CMRR) and low noise efficiency factor (NEF). The proposed circuit has been implemented in the 0.5um CMOS...

Dwobeng, Ebenezer

2012-02-14

212

A critical examination of the evidence relating high fructose corn syrup and weight gain  

Technology Transfer Automated Retrieval System (TEKTRAN)

The use of high fructose corn syrup (HFCS) has increased over the past several decades in the United States while overweight and obesity rates have risen dramatically. Some scientists hypothesize that HFCS consumption has uniquely contributed to the increasing mean body mass index (BMI) of the U.S....

213

Full characterization of the amplified spontaneous emission from a diode-pumped high-power laser system.  

PubMed

We present the first complete temporal and spatial characterization of the amplified spontaneous emission (ASE) of laser radiation generated by a diode-pumped high-power laser system. The ASE of the different amplifiers was measured independently from the main pulse and was characterized within a time window of -10ms ? t ? 10ms and an accuracy of up to 15fs around the main pulse. Furthermore, the focusability and the energy of the ASE from each amplifier was measured after recompression. Using our analysis method, the laser components, which need to be optimized for a further improvement of the laser contrast, can be identified. This will be essential for laser-matter interaction experiments requiring a minimized ASE intensity or fluence. PMID:24921820

Keppler, S; Hornung, M; Bödefeld, R; Sävert, A; Liebetrau, H; Hein, J; Kaluza, M C

2014-05-01

214

High matrix metalloproteinase-9 expression induces angiogenesis and basement membrane degradation in stroke-prone spontaneously hypertensive rats after cerebral infarction  

PubMed Central

Basement membrane degradation and blood-brain barrier damage appear after cerebral infarction, severely impacting neuronal and brain functioning; however, the underlying pathogenetic mechanisms remain poorly understood. In this study, we induced cerebral infarction in stroke-prone spontaneously hypertensive rats by intragastric administration of high-sodium water (1.3% NaCl) for 7 consecutive weeks. Immunohistochemical and immunofluorescence assays demonstrated that, compared with the non-infarcted contralateral hemisphere, stroke-prone spontaneously hypertensive rats on normal sodium intake and Wistar-Kyoto rats, matrix metalloproteinase-9 expression, the number of blood vessels with discontinuous collagen IV expression and microvessel density were significantly higher, and the number of continuous collagen IV-positive blood vessels was lower in the infarct border zones of stroke-prone spontaneously hypertensive rats given high-sodium water. Linear correlation analysis showed matrix metalloproteinase-9 expression was positively correlated with the number of discontinuously collagen IV-labeled blood vessels and microvessel density in cerebral infarcts of stroke-prone spontaneously hypertensive rats. These results suggest that matrix metalloproteinase-9 upregulation is associated with increased regional angiogenesis and degradation of collagen IV, the major component of the basal lamina, in stroke-prone spontaneously hypertensive rats with high-sodium water-induced focal cerebral infarction. PMID:25206775

Hou, Huilian; Zhang, Guanjun; Wang, Hongyan; Gong, Huilin; Wang, Chunbao; Zhang, Xuebin

2014-01-01

215

Characteristics of trap-filled gallium arsenide photoconductive switches used in high gain pulsed power applications  

SciTech Connect

The electrical properties of semi-insulating (SI) Gallium Arsenide (GaAs) have been investigated for some time, particularly for its application as a substrate in microelectronics. Of late this material has found a variety of applications other than as an isolation region between devices, or the substrate of an active device. High resistivity SI GaAs is increasingly being used in charged particle detectors and photoconductive semiconductor switches (PCSS). PCSS made from these materials operating in both the linear and non-linear modes have applications such as firing sets, as drivers for lasers, and in high impedance, low current Q-switches or Pockels cells. In the non-linear mode, it has also been used in a system to generate Ultra-Wideband (UWB) High Power Microwaves (HPM). The choice of GaAs over silicon offers the advantage that its material properties allow for fast, repetitive switching action. Furthermore photoconductive switches have advantages over conventional switches such as improved jitter, better impedance matching, compact size, and in some cases, lower laser energy requirement for switching action. The rise time of the PCSS is an important parameter that affects the maximum energy transferred to the load and it depends, in addition to other parameters, on the bias or the average field across the switch. High field operation has been an important goal in PCSS research. Due to surface flashover or premature material breakdown at higher voltages, most PCSS, especially those used in high power operation, need to operate well below the inherent breakdown voltage of the material. The lifetime or the total number of switching operations before breakdown, is another important switch parameter that needs to be considered for operation at high bias conditions. A lifetime of {approximately} 10{sup 4} shots has been reported for PCSS's used in UWB-HPM generation [5], while it has exceeded 10{sup 8} shots for electro-optic drivers. Much effort is currently being channeled in the study related to improvements of these two parameters high bias operation and lifetime improvement for switches used in pulsed power applications. The contact material and profiles are another important area of study. Although these problems are being pursued through the incorporation of different contact materials and introducing doping near contacts, it is important that the switch properties and the conduction mechanism in these switches be well understood such that the basic nature of the problems can be properly addressed. In this paper the authors report on these two basic issues related to the device operation, i.e., mechanisms for increasing the hold-off characteristics through neutron irradiation, and the analysis of transport processes at varying field conditions in trap dominated SI GaAs in order to identify the breakdown mechanism during device operation. It is expected that this study would result in a better understanding of photoconductive switches, specifically those used in high power operation.

ISLAM,N.E.; SCHAMILOGLU,E.; MAR,ALAN; LOUBRIEL,GUILLERMO M.; ZUTAVERN,FRED J.; JOSHI,R.P.

2000-05-30

216

Sinusoidal voltage control of a single phase uninterruptible power supply by a high gain PI circuit  

Microsoft Academic Search

This paper presents analysis and design of a new control method of a single-phase voltage-source uninterruptible power supply (UPS) inverter with a high Q L-C low-pass filter. When a PWM inverter is used to feed the load, a L-C low-pass filter must be employed to eliminate the switching frequency component of output voltage harmonics. But, it may be observed that

Akira Moriyama; I. Ando; I. Takahashi

1998-01-01

217

Anisotropic metamaterial lens with a monopole feed for high-gain multi-beam radiation  

Microsoft Academic Search

In this paper, we present both the theory and design of an anisotropic metamaterial lens for antenna applications. This type of lens requires simple effective medium tensor parameters to achieve highly-directive radiated beams, which differs from more conventional isotropic zero-index metamaterial lenses. Making use of the less dispersive low permittivity and\\/or permeability band, the lens is promising for wideband applications.

Zhi Hao Jiang; Douglas H. Werner

2011-01-01

218

Caffeine prevents weight gain and cognitive impairment caused by a high-fat diet while elevating hippocampal BDNF  

PubMed Central

Obesity, high-fat diets, and subsequent type 2 diabetes (T2DM) are associated with cognitive impairment. Moreover, T2DM increases the risk of Alzheimer’s disease (AD) and leads to abnormal elevation of brain beta-amyloid levels, one of the hallmarks of AD. The psychoactive alkaloid caffeine has been shown to have therapeutic potential in AD but the central impact of caffeine has not been well-studied in the context of a high-fat diet. Here we investigated the impact of caffeine administration on metabolism and cognitive performance, both in control rats and in rats placed on a high-fat diet. The effects of caffeine were significant: caffeine both (i) prevented the weight-gain associated with the high-fat diet and (ii) prevented cognitive impairment. Caffeine did not alter hippocampal metabolism or insulin signaling, likely because the high-fat-fed animals did not develop full-blown diabetes; however, caffeine did prevent or reverse a decrease in hippocampal brain-derived neurotrophic factor (BDNF) seen in high-fat-fed animals. These data confirm that caffeine may serve as a neuroprotective agent against cognitive impairment caused by obesity and/or a high-fat diet. Increased hippocampal BDNF following caffeine administration could explain, at least in part, the effects of caffeine on cognition and metabolism. PMID:23220362

Moy, Gregory A.; McNay, Ewan C.

2013-01-01

219

High gain CMOS image sensor design and fabrication on SOI and bulk technology  

NASA Astrophysics Data System (ADS)

The CMOS imager is now competing with the CCD imager, which still dominates the electronic imaging market. By taking advantage of the mature CMOS technology, the CMOS imager can integrate AID converters, digital signal processing (DSP) and timing control circuits on the same chip. This low cost and high-density integration solution to the image capture is the strong driving force in industry. Silicon on insulator (SOI) is considered as the coming mainstream technology. It challenges the current bulk CMOS technology because of its reduced power consumption, high speed, radiation hardness etc. Moving the CMOS imager from the bulk to the SOI substrate will benefit from these intrinsic advantages. In addition, the blooming and the cross-talk between the pixels of the sensor array can be ideally eliminated, unlike those on the bulk technology. Though there are many advantages to integrate CMOS imager on SOI, the problem is that the top silicon film is very thin, such as 2000Å. Many photons can just pass through this layer without being absorbed. A good photo-detector on SOI is critical to integrate SOI CMOS imagers. In this thesis, several methods to make photo-detectors on SOI substrate are investigated. A floating gate MOSFET on SOI substrate, operating in its lateral bipolar mode, is photon sensitive. One step further, the SOI MOSFET gate and body can be tied together. The positive feedback between the body and gate enables this device have a high responsivity. A similar device can be found on the bulk CMOS technology: the gate-well tied PMOSFET. A 32 x 32 CMOS imager is designed and characterized using such a device as the light-sensing element. I also proposed the idea of building hybrid active pixels on SOI substrate. Such devices are fabricated and characterized. The work here represents my contribution on the CMOS imager, especially moving the CMOS imager onto the SOI substrate.

Zhang, Weiquan

2000-12-01

220

A high calcium diet containing nonfat dry milk reduces weight gain and associated adipose tissue inflammation in diet-induced obese mice when compared to high calcium alone  

PubMed Central

Background High dietary calcium (Ca) is reported to have anti-obesity and anti-inflammatory properties. Evidence for these properties of dietary Ca in animal models of polygenic obesity have been confounded by the inclusion of dairy food components in experimental diets; thus, effect of Ca per se could not be deciphered. Furthermore, potential anti-inflammatory actions of Ca in vivo could not be dissociated from reduced adiposity. Methods We characterized adiposity along with metabolic and inflammatory phenotypes in diet-induced obese (DIO) mice fed 1 of 3 high fat diets (45% energy) for 12 wk: control (n = 29), high-Ca (n = 30), or high-Ca + nonfat dry milk (NFDM) (n = 30). Results Mice fed high-Ca + NFDM had reduced body weight and adiposity compared to high-Ca mice (P < 0.001). Surprisingly, the high-Ca mice had increased adiposity compared to lower-Ca controls (P < 0.001). Hyperphagia and increased feed efficiency contributed to obesity development in high-Ca mice, in contrast to NFDM mice that displayed significantly reduced weight gain despite higher energy intake compared to controls (P < 0.001). mRNA markers of macrophages (e.g., CD68, CD11d) strongly correlated with body weight in all diet treatment groups, and most treatment differences in WAT inflammatory factor mRNA abundances were lost when controlling for body weight gain as a covariate. Conclusions The results indicate that high dietary Ca is not sufficient to dampen obesity-related phenotypes in DIO mice, and in fact exacerbates weight gain and hyperphagia. The data further suggest that putative anti-obesity properties of dairy emanate from food components beyond Ca. PMID:22269778

2012-01-01

221

Theory of quantum frequency conversion and type-II parametric down-conversion in the high-gain regime  

NASA Astrophysics Data System (ADS)

Frequency conversion (FC) and type-II parametric down-conversion (PDC) processes serve as basic building blocks for the implementation of quantum optical experiments: type-II PDC enables the efficient creation of quantum states such as photon-number states and Einstein-Podolsky-Rosen (EPR)-states. FC gives rise to technologies enabling efficient atom-photon coupling, ultrafast pulse gates and enhanced detection schemes. However, despite their widespread deployment, their theoretical treatment remains challenging. Especially the multi-photon components in the high-gain regime as well as the explicit time-dependence of the involved Hamiltonians hamper an efficient theoretical description of these nonlinear optical processes. In this paper, we investigate these effects and put forward two models that enable a full description of FC and type-II PDC in the high-gain regime. We present a rigorous numerical model relying on the solution of coupled integro-differential equations that covers the complete dynamics of the process. As an alternative, we develop a simplified model that, at the expense of neglecting time-ordering effects, enables an analytical solution. While the simplified model approximates the correct solution with high fidelity in a broad parameter range, sufficient for many experimental situations, such as FC with low efficiency, entangled photon-pair generation and the heralding of single photons from type-II PDC, our investigations reveal that the rigorous model predicts a decreased performance for FC processes in quantum pulse gate applications and an enhanced EPR-state generation rate during type-II PDC, when EPR squeezing values above 12 dB are considered.

Christ, Andreas; Brecht, Benjamin; Mauerer, Wolfgang; Silberhorn, Christine

2013-05-01

222

Modeling and output tracking of transverse flux permanent magnet machines using high gain observer and RBF neural network.  

PubMed

This paper deals with modeling and adaptive output tracking of a transverse flux permanent magnet machine as a nonlinear system with unknown nonlinearities by utilizing high gain observer and radial basis function networks. The proposed model is developed based on computing the permeance between rotor and stator using quasiflux tubes. Based on this model, the techniques of feedback linearization and Hinfinity control are used to design an adaptive control law for compensating the unknown nonlinear parts, such as the effect of cogging torque, as a disturbance is decreased onto the rotor angle and angular velocity tracking performances. Finally, the capability of the proposed method in tracking both the angle and the angular velocity is shown in the simulation results. PMID:16294772

Karimi, H R; Babazadeh, A

2005-10-01

223

Gimbals Drive and Control Electronics Design, Development and Testing of the LRO High Gain Antenna and Solar Array Systems  

NASA Technical Reports Server (NTRS)

Launched June 18, 2009 on an Atlas V rocket, NASA's Lunar Reconnaissance Orbiter (LRO) is the first step in NASA's Vision for Space Exploration program and for a human return to the Moon. The spacecraft (SC) carries a wide variety of scientific instruments and provides an extraordinary opportunity to study the lunar landscape at resolutions and over time scales never achieved before. The spacecraft systems are designed to enable achievement of LRO's mission requirements. To that end, LRO's mechanical system employed two two-axis gimbal assemblies used to drive the deployment and articulation of the Solar Array System (SAS) and the High Gain Antenna System (HGAS). This paper describes the design, development, integration, and testing of Gimbal Control Electronics (GCE) and Actuators for both the HGAS and SAS systems, as well as flight testing during the on-orbit commissioning phase and lessons learned.

Chernyakov, Boris; Thakore, Kamal

2010-01-01

224

Inactivation of Enhanced Expression of Gi Proteins by Pertussis Toxin Attenuates the Development of High Blood Pressure in Spontaneously Hypertensive Rats  

Microsoft Academic Search

We have previously shown that the enhanced expression of Gi proteins in spontaneously hypertensive rats (SHR) that precedes the development of high blood pressure may be one of the contributing factors in the pathogenesis of hypertension. In the present study, we demonstrate that the inactivation of G i proteins by intraperitoneal injection of pertussis toxin (PT, 1.5 g\\/100 g body

Yuan Li; Madhu B. Anand-Srivastava

225

Do High-Functioning People with Autism Spectrum Disorder Spontaneously Use Event Knowledge to Selectively Attend to and Remember Context-Relevant Aspects in Scenes?  

ERIC Educational Resources Information Center

This study combined an event schema approach with top-down processing perspectives to investigate whether high-functioning children and adults with autism spectrum disorder (ASD) spontaneously attend to and remember context-relevant aspects of scenes. Participants read one story of story-pairs (e.g., burglary or tea party). They then inspected a…

Loth, Eva; Gomez, Juan Carlos; Happe, Francesca

2011-01-01

226

A low-carbohydrate/high-fat diet reduces blood pressure in spontaneously hypertensive rats without deleterious changes in insulin resistance  

PubMed Central

Previous studies reported that diets high in simple carbohydrates could increase blood pressure in rodents. We hypothesized that the converse, a low-carbohydrate/high-fat diet, might reduce blood pressure. Six-week-old spontaneously hypertensive rats (SHR; n = 54) and Wistar-Kyoto rats (WKY; n = 53, normotensive control) were fed either a control diet (C; 10% fat, 70% carbohydrate, 20% protein) or a low-carbohydrate/high-fat diet (HF; 20% carbohydrate, 60% fat, 20% protein). After 10 wk, SHR-HF had lower (P < 0.05) mean arterial pressure than SHR-C (148 ± 3 vs. 159 ± 3 mmHg) but a similar degree of cardiac hypertrophy (33.4 ± 0.4 vs. 33.1 ± 0.4 heart weight/tibia length, mg/mm). Mesenteric arteries and the entire aorta were used to assess vascular function and endothelial nitric oxide synthase (eNOS) signaling, respectively. Endothelium-dependent (acetylcholine) relaxation of mesenteric arteries was improved (P < 0.05) in SHR-HF vs. SHR-C, whereas contraction (potassium chloride, phenylephrine) was reduced (P < 0.05). Phosphorylation of eNOSSer1177 increased (P < 0.05) in arteries from SHR-HF vs. SHR-C. Plasma glucose, insulin, and homoeostatic model of insulin assessment were lower (P < 0.05) in SHR-HF vs. SHR-C, whereas peripheral insulin sensitivity (insulin tolerance test) was similar. After a 10-h fast, insulin stimulation (2 U/kg ip) increased (P < 0.05) phosphorylation of AktSer473 and S6 in heart and gastrocnemius similarly in SHR-C vs. SHR-HF. In conclusion, a low-carbohydrate/high-fat diet reduced blood pressure and improved arterial function in SHR without producing signs of insulin resistance or altering insulin-mediated signaling in the heart, skeletal muscle, or vasculature. PMID:23604708

Bosse, John D.; Lin, Han Yi; Sloan, Crystal; Zhang, Quan-Jiang; Abel, E. Dale; Pereira, Troy J.; Dolinsky, Vernon W.; Symons, J. David

2013-01-01

227

Fabrication and materials for magneto-photonic assemblies for high-gain antenna applications at GHz frequencies  

NASA Astrophysics Data System (ADS)

Recent magnetic photonic assembly (MPA) designs for high-gain antennas contain arrays of low-loss, anisotropic dielectrics and ferrimagnetic materials. Anisotropic dielectrics (AD) are fabricated from laminates, which consist of two ceramics with largely different permittivity and low dielectric losses at GHz frequencies. High gain has been demonstrated in a prototype antenna with 2 sets of 3 mutually rotated AD layers. These layers were made from laminates of commercially available alpha-Al2O3 and Nd-doped barium titanate. Equivalent permittivity tensors and loss tangents (tan delta˜1.9x10-3) were characterized using a resonant cavity based approach, coupled with a finite-element method (FEM) full-wave solver. To enable further minimization of dielectric loss (tan delta), dense high-purity alpha-Al2O3 and TiO2 were prepared starting from colloidally stabilizing the powders in aqueous HNO3 or NH3. After colloidal filtration and sintering, alpha-Al 2O3 with >97.9% density was achieved at a sintering temperature of 1300°C, and TiO2 with >99.5% density was obtained at 1000°C. These low sintering temperatures are ascribed to excellent compact homogeneity. TiO2 was obtained with tan delta of 1.4x10-4 at 6.4 GHz at room temperature. This relatively low value is attributed to the homogeneous dense microstructure with 2.2 mum grain size. Al 3+ was doped into TiO2 using a modified infiltration method to compensate for the effect of Ti4+ reduction. A homogeneous microstructure and doping concentration were also observed in the doped dense TiO2. Substituted Y3Fe5O12 (YIG) garnet was chosen as the ferrimagnetic (F) component, due to its pronounced Faraday rotation effect and potentially low magnetic and dielectric loss. Phase pure garnet was prepared by using the citric-gel method. The magnetic properties were studied for Ca,V,Zr-substituted YIG (CVZG) and as-prepared particle morphology. Compacts of CVZG submicron particles were found to possess a low loss at GHz frequencies, and will be applied in future MPAs structures.

Zhang, Lanlin

228

SPONTANEOUS CATALYTIC WET AIR OXIDATION DURING PRE-TREATMENT OF HIGH-LEVEL RADIOACTIVE WASTE SLUDGE  

SciTech Connect

Savannah River Remediation, LLC (SRR) operates the Defense Waste Processing Facility for the U.S. Department of Energy at the Savannah River Site. This facility immobilizes high-level radioactive waste through vitrification following chemical pretreatment. Catalytic destruction of formate and oxalate ions to carbon dioxide has been observed during qualification testing of non-radioactive analog systems. Carbon dioxide production greatly exceeded hydrogen production, indicating the occurrence of a process other than the catalytic decomposition of formic acid. Statistical modeling was used to relate the new reaction chemistry to partial catalytic wet air oxidation of both formate and oxalate ions driven by the low concentrations of palladium, rhodium, and/or ruthenium in the waste. Variations in process conditions led to increases or decreases in the total oxidative destruction, as well as partially shifting the preferred species undergoing destruction from oxalate ion to formate ion.

Koopman, D.; Herman, C.; Pareizs, J.; Bannochie, C.; Best, D.; Bibler, N.; Fellinger, T.

2009-10-01

229

Consumption of Clarified Grapefruit Juice Ameliorates High-Fat Diet Induced Insulin Resistance and Weight Gain in Mice  

PubMed Central

To determine the metabolic effects of grapefruit juice consumption we established a model in which C57Bl/6 mice drank 25–50% sweetened GFJ, clarified of larger insoluble particles by centrifugation (cGFJ), ad libitum as their sole source of liquid or isocaloric and sweetened water. cGFJ and control groups consumed similar amounts of liquids and calories. Mice fed a high-fat diet and cGFJ experienced a 18.4% decrease in weight, a 13–17% decrease in fasting blood glucose, a three-fold decrease in fasting serum insulin, and a 38% decrease in liver triacylglycerol values, compared to controls. Mice fed a low-fat diet that drank cGFJ experienced a two-fold decrease in fasting insulin, but not the other outcomes observed with the high-fat diet. cGFJ consumption decreased blood glucose to a similar extent as the commonly used anti-diabetic drug metformin. Introduction of cGFJ after onset of diet-induced obesity also reduced weight and blood glucose. A bioactive compound in cGFJ, naringin, reduced blood glucose and improved insulin tolerance, but did not ameliorate weight gain. These data from a well-controlled animal study indicate that GFJ contains more than one health-promoting neutraceutical, and warrant further studies of GFJ effects in the context of obesity and/or the western diet. PMID:25296035

Chudnovskiy, Rostislav; Thompson, Airlia; Tharp, Kevin; Hellerstein, Marc; Napoli, Joseph L.; Stahl, Andreas

2014-01-01

230

High-Gain, Polarization-Perserving, Yb-Doped Fiber Amplifier for Low-Duty-Cycle Pulse Amplification  

SciTech Connect

An alignment-free, dual-pass, ytterbium-doped fiber amplifier with 25-dB gain and -44 dB noise floor is demonstrated for amplifying linearly polarized optical pulses with low duty cycle at a wavelength 23 nm off the gain peak.

Marciante, J.R.; Zuegel, J.D.

2005-09-30

231

Low- but Not High-Frequency LFP Correlates with Spontaneous BOLD Fluctuations in Rat Whisker Barrel Cortex.  

PubMed

Resting-state magnetic resonance imaging (rsMRI) is thought to reflect ongoing spontaneous brain activity. However, the precise neurophysiological basis of rsMRI signal remains elusive. Converging evidence supports the notion that local field potential (LFP) signal in the high-frequency range correlates with fMRI response evoked by a task (e.g., visual stimulation). It remains uncertain whether this relationship extends to rsMRI. In this study, we systematically modulated LFP signal in the whisker barrel cortex (WBC) by unilateral deflection of rat whiskers. Results show that functional connectivity between bilateral WBC was significantly modulated at the 2 Hz, but not at the 4 or 6 Hz, stimulus condition. Electrophysiologically, only in the low-frequency range (<5 Hz) was the LFP power synchrony in bilateral WBC significantly modulated at 2 Hz, but not at 4- or 6-Hz whisker stimulation, thus distinguishing these 2 experimental conditions, and paralleling the findings in rsMRI. LFP power synchrony in other frequency ranges was modulated in a way that was neither unique to the specific stimulus conditions nor parallel to the fMRI results. Our results support the hypothesis that emphasizes the role of low-frequency LFP signal underlying rsMRI. PMID:25331598

Lu, Hanbing; Wang, Leiming; Rea, William W; Brynildsen, Julia K; Jaime, Saul; Zuo, Yantao; Stein, Elliot A; Yang, Yihong

2014-10-20

232

Soluble epoxide hydrolase in the generation and maintenance of high blood pressure in spontaneously hypertensive rats  

PubMed Central

We hypothesized that perinatal inhibition of soluble epoxide hydrolase (SEH), which metabolizes epoxyeicosatrienoic acids in the arachidonic acid (AA) cascade, with an orally active SEH inhibitor, 12-(3-adamantan-1-yl-ureido)-dodecanoic acid (AUDA), would persistently reduce blood pressure (BP) in adult SHR despite discontinuation of AUDA at 4 wk of age. Renal cytoplasmic epoxide hydrolase-2 (Ephx2) gene expression was enhanced in SHR vs. WKY from 2 days to 24 wk. Effects of perinatal treatment with AUDA, supplied to SHR dams until 4 wk after birth, on BP in female and male offspring and renal oxylipin metabolome in female offspring were observed and contrasted to female SHR for direct effects of AUDA (8–12 wk). Briefly, inhibition of SEH was effective in persistently reducing BP in female SHR when applied during the perinatal phase. This was accompanied by marked increases in major renal AA epoxides and decreases in renal lipoxygenase products of AA. Early inhibition of SEH induced a delayed increase in renal 5-HETE at 24 wk, in contrast to a decrease at 2 wk. Inhibition of SEH in female SHR from 8 to 12 wk did not reduce BP but caused profound decreases in renal 15(S)-HETrE, LTB4, TBX2, 5-HETE, and 20-HETE and increases in TriHOMEs. In male SHR, BP reduction after perinatal AUDA was transient. Thus, Ephx2 transcription and SEH activity in early life may initiate mechanisms that eventually contribute to high BP in adult female SHR. However, programmed BP-lowering effects of perinatal SEH inhibition in female SHR cannot be simply explained by persistent reduction in renal SEH activity but rather by more complex and temporally dynamic interactions between the renal SEH, lipoxygenase, and cyclooxygenase pathways. PMID:21266668

Koeners, Maarten P.; Wesseling, Sebastiaan; Ulu, Arzu; Sepúlveda, Rocío López; Morisseau, Christophe; Braam, Branko; Hammock, Bruce D.

2011-01-01

233

High-Gain, Polarization-Preserving, Yb-Doped Fiber Amplifier for Low-Duty-Cycle Pulse Amplification  

SciTech Connect

Amplified spontaneous emission (ASE) suppression techniques were utilized to fabricate a double-pass, Yb-doped amplifier with the noise properties of a single-pass amplifier. Simulations based on a rate equation model were used to analyze the ASE and the effectiveness of the suppression techniques.

Marciante, J.R.; Zuegel, J.D.

2006-08-22

234

Green tea decoction improves glucose tolerance and reduces weight gain of rats fed normal and high-fat diet.  

PubMed

Green tea containing polyphenols exerts antidiabetic and antiobesity effects, but the mechanisms involved are not fully understood. In this study, we first analyzed and compared polyphenol compounds [epigallocatechin gallate (EGCG), epigallocatechin (EGC)] in decoction of green tea leaves versus usual green tea extracts. Second, the effects of acute (30 min) or chronic (6 weeks) oral administration of green tea decoction (GTD) on intestinal glucose absorption were studied in vitro in Ussing chamber, ex vivo using isolated jejunal loops and in vivo through glucose tolerance tests. Finally, we explore in rat model fed normal or high-fat diet the effects of GTD on body weight, blood parameters and on the relative expression of glucose transporters SGLT-1, GLUT2 and GLUT4. GTD cooked for 15 min contained the highest amounts of phenolic compounds. In fasted rats, acute administration of GTD inhibited SGLT-1 activity, increased GLUT2 activity and improved glucose tolerance. Similarly to GTD, acute administration of synthetic phenolic compounds (2/3 EGCG+1/3 EGC) inhibited SGLT-1 activity. Chronic administration of GTD in rat fed high-fat diet reduced body weight gain, circulating triglycerides and cholesterol and improved glucose tolerance. GTD-treated rats for 6 weeks display significantly reduced SGLT-1 and increased GLUT2 mRNA levels in the jejunum mucosa. Moreover, adipose tissue GLUT4 mRNA levels were increased. These results indicate that GTD, a traditional beverage rich in EGCG and EGC reduces intestinal SGLT-1/GLUT2 ratio, a hallmark of regulation of glucose absorption in enterocyte, and enhances adipose GLUT4 providing new insights in its possible role in the control of glucose homeostasis. PMID:24656388

Snoussi, Chahira; Ducroc, Robert; Hamdaoui, Mohamed Hédi; Dhaouadi, Karima; Abaidi, Houda; Cluzeaud, Francoise; Nazaret, Corinne; Le Gall, Maude; Bado, André

2014-05-01

235

A low-cost equalizer-based auto-gain-control scheme for high-speed transceiver applications  

Microsoft Academic Search

Traditional approaches of auto-gain control (AGC) need to collect long period of data and estimate the average power. It results in the large hardware complexity. Moreover, the accuracy of traditional approaches will be seriously degraded by noise and inter-symbol interference (ISI). In this paper, we propose an equalizer-based auto-gain control (EQ-AGC), which employs very small hardware and does not use

J. J. Lai; Chien-Hsiung Lee; Hsin-Shih Wang

2005-01-01

236

The X-Target: A novel high gain target with single-sided heavy-ion beam illumination  

NASA Astrophysics Data System (ADS)

A new inertial-fusion target configuration, the X-target, using one-sided heavy ion axial illumination has been explored [1]. It takes advantage of the unique energy deposition properties of heavy ion beams that have a classical, long penetration range. This class of target uses heavy ion beams to compress and ignite deuterium-tritium (DT) fuel that fills the interior of metal cases that have side-view cross sections in the shape of an ``X''. X-targets that incorporate inside the case a propellant (plastic) and a pusher (aluminum) surrounding the DT are capable of assembling fuel areal densities ˜2 g/cm^2 using two MJ-scale annular beams to implode quasi-spherically the target to peak DT densities ˜100 g/cm^3. A 3MJ fast-ignition solid ion beam heats the fuel to thermonuclear temperatures in ˜200 ps to start the burn propagation, obtaining gains of ˜300. The main concern for the X-target is the amount of high-Z atomic mixing at the ignition zone produced by hydro-instabilities, which, if large enough, could cool the fuel during the ignition process and prevent the propagation of the fusion burn. Analytic estimates and implosion calculations using the radiation hydrodynamics code HYDRA in 2D (RZ), at typical Eulerian mesh resolutions of a few microns, have shown that for the relatively low implosion velocities, low stagnation fuel densities, and low quasi-spherical fuel convergence ratios of the X-target, these hydro-instabilities do not have a large effect on the burning process. These preliminary studies need to be extended by further hydrodynamic calculations using finer resolution, complemented with turbulent mix modeling and validated by experiments, to ascertain the stability of the X-target design. We will present the current status of the X-target. [4pt] [1] E. Henestroza and B. G. Logan, Phys. Plasmas 19, 072706 (2012)

Henestroza, Enrique

2012-10-01

237

A high-fat, ketogenic diet causes hepatic insulin resistance in mice, despite increasing energy expenditure and preventing weight gain.  

PubMed

Low-carbohydrate, high-fat ketogenic diets (KD) have been suggested to be more effective in promoting weight loss than conventional caloric restriction, whereas their effect on hepatic glucose and lipid metabolism and the mechanisms by which they may promote weight loss remain controversial. The aim of this study was to explore the role of KD on liver and muscle insulin sensitivity, hepatic lipid metabolism, energy expenditure, and food intake. Using hyperinsulinemic-euglycemic clamps, we studied insulin action in mice fed a KD or regular chow (RC). Body composition was assessed by ¹H magnetic resonance spectroscopy. Despite being 15% lighter (P < 0.001) than RC-fed mice because of a 17% increase in energy expenditure (P < 0.001), KD-fed mice manifested severe hepatic insulin resistance, as reflected by decreased suppression (0% vs. 100% in RC-fed mice, P < 0.01) of endogenous glucose production during the clamp. Hepatic insulin resistance could be attributed to a 350% increase in hepatic diacylglycerol content (P < 0.001), resulting in increased activation of PKC? (P < 0.05) and decreased insulin receptor substrate-2 tyrosine phosphorylation (P < 0.01). Food intake was 56% (P < 0.001) lower in KD-fed mice, despite similar caloric intake, and could partly be attributed to a more than threefold increase (P < 0.05) in plasma N-acylphosphatidylethanolamine concentrations. In conclusion, despite preventing weight gain in mice, KD induces hepatic insulin resistance secondary to increased hepatic diacylglycerol content. Given the key role of nonalcoholic fatty liver disease in the development of type 2 diabetes and the widespread use of KD for the treatment of obesity, these results may have potentially important clinical implications. PMID:20807839

Jornayvaz, François R; Jurczak, Michael J; Lee, Hui-Young; Birkenfeld, Andreas L; Frederick, David W; Zhang, Dongyang; Zhang, Xian-Man; Samuel, Varman T; Shulman, Gerald I

2010-11-01

238

A high-fat, ketogenic diet causes hepatic insulin resistance in mice, despite increasing energy expenditure and preventing weight gain  

PubMed Central

Low-carbohydrate, high-fat ketogenic diets (KD) have been suggested to be more effective in promoting weight loss than conventional caloric restriction, whereas their effect on hepatic glucose and lipid metabolism and the mechanisms by which they may promote weight loss remain controversial. The aim of this study was to explore the role of KD on liver and muscle insulin sensitivity, hepatic lipid metabolism, energy expenditure, and food intake. Using hyperinsulinemic-euglycemic clamps, we studied insulin action in mice fed a KD or regular chow (RC). Body composition was assessed by 1H magnetic resonance spectroscopy. Despite being 15% lighter (P < 0.001) than RC-fed mice because of a 17% increase in energy expenditure (P < 0.001), KD-fed mice manifested severe hepatic insulin resistance, as reflected by decreased suppression (0% vs. 100% in RC-fed mice, P < 0.01) of endogenous glucose production during the clamp. Hepatic insulin resistance could be attributed to a 350% increase in hepatic diacylglycerol content (P < 0.001), resulting in increased activation of PKC? (P < 0.05) and decreased insulin receptor substrate-2 tyrosine phosphorylation (P < 0.01). Food intake was 56% (P < 0.001) lower in KD-fed mice, despite similar caloric intake, and could partly be attributed to a more than threefold increase (P < 0.05) in plasma N-acylphosphatidylethanolamine concentrations. In conclusion, despite preventing weight gain in mice, KD induces hepatic insulin resistance secondary to increased hepatic diacylglycerol content. Given the key role of nonalcoholic fatty liver disease in the development of type 2 diabetes and the widespread use of KD for the treatment of obesity, these results may have potentially important clinical implications. PMID:20807839

Jornayvaz, François R.; Jurczak, Michael J.; Lee, Hui-Young; Birkenfeld, Andreas L.; Frederick, David W.; Zhang, Dongyang; Zhang, Xian-Man; Samuel, Varman T.

2010-01-01

239

1050 IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 57, NO. 4, APRIL 2009 A 60-GHz CPW-Fed High-Gain and Broadband  

E-print Network

-Fed High-Gain and Broadband Integrated Horn Antenna Bo Pan, Member, IEEE, Yuan Li, Student Member, IEEE Member, IEEE Abstract--An integrated horn antenna is presented for 60-GHz WPAN applications. Compared with other types of antenna for 60-GHz WPAN applications, an integrated horn antenna features wide bandwidth

Tentzeris, Manos

240

2296 IEEE TRANSACTIONS ON ELECTRON DEVICES, VOL. 60, NO. 7, JULY 2013 Dual-Carrier High-Gain Low-Noise Superlattice  

E-print Network

photodiodes (APDs) directly into silicon read-out cir- cuits. In this paper, type-II mid-wavelength infrared-carrier APDs, with carrier feedback to generate high gain and control of excess noise through confining impact ionization in thin layers, is general and can also be applied to other wavelength APDs with different

Hayat, Majeed M.

241

Gaining Acceptance  

ERIC Educational Resources Information Center

Back in the 1990s, when Bill Clinton was president and the internet was still a novelty, college recruitment was remarkably low-tech. Most prospective students visited high school guidance offices, wrote away for information about schools, attended college fairs, and visited campuses they were considering. Most admissions and recruiting activities…

Villano, Matt

2007-01-01

242

High energy gain of trapped electrons in a tapered, diffraction-dominated inverse-free-electron laser.  

PubMed

Energy gain of trapped electrons in excess of 20 MeV has been demonstrated in an inverse-free-electron-laser (IFEL) accelerator experiment. A 14.5 MeV electron beam is copropagated with a 400 GW CO2 laser beam in a 50 cm long undulator strongly tapered in period and field amplitude. The Rayleigh range of the laser, approximately 1.8 cm, is much shorter than the undulator length yielding a diffraction-dominated interaction. Experimental results on the dependence of the acceleration on injection energy, laser focus position, and laser power are discussed. Simulations, in good agreement with the experimental data, show that most of the energy gain occurs in the first half of the undulator at a gradient of 70 MeV/m and that the structure in the measured energy spectrum arises because of higher harmonic IFEL interaction in the second half of the undulator. PMID:15904152

Musumeci, P; Tochitsky, S Ya; Boucher, S; Clayton, C E; Doyuran, A; England, R J; Joshi, C; Pellegrini, C; Ralph, J E; Rosenzweig, J B; Sung, C; Tolmachev, S; Travish, G; Varfolomeev, A A; Varfolomeev, A A; Yarovoi, T; Yoder, R B

2005-04-22

243

High gain-density K-band P-HEMT LNA MMIC for LMDS and satellite communication  

Microsoft Academic Search

A miniature and broadband, K-band p-HEMT LNA MMIC, that incorporates simple lumped matching elements and series bias topologies, has been developed for LMDS (Local Multi-point Distribution Service) and satellite communication. The gain and noise figure is 14.5 +\\/- 1.5 dB and 1.7 +\\/- 0.2 dB, respectively, at frequencies between 23 and 30 GHz. The die size of the MMIC is

Yutaka Mimino; M. Hirata; K. Nakamura; K. Sakamoto; Y. Aoki; S. Kuroda

2000-01-01

244

Lu2O3:Yb3+ ceramics - a novel gain material for high-power solid-state lasers  

Microsoft Academic Search

We have developed Yb3+:Lu2O3 ceramics with nanocrystalline technology and a vacuum sintering method. A laser diode end-pumped efficient Yb3+:Lu2O3 ceramic laser was demonstrated. A 0.7 W cw output power was obtained with the slope efficiency of 36% at 1035 nm wavelength, and 0.95 W with the slope efficiency of 53% at 1079 nm. We classify the Lu2O3:Yb3+ ceramics as gain

K. Takaichi; H. Yagi; A. Shirakawa; K. Ueda; S. Hosokawa; T. Yanagitani; A. A. Kaminskii

2005-01-01

245

Experiment on suppression of spontaneous undulator radiation at ATF  

SciTech Connect

We propose undertaking a demonstration experiment on suppressing spontaneous undulator radiation from an electron beam at BNL's Accelerator Test Facility (ATF). We describe the method, the proposed layout, and a possible schedule. There are several advantages in strongly suppressing shot noise in the electron beam, and the corresponding spontaneous radiation. The self-amplified spontaneous (SASE) emission originating from shot noise in the electron beam is the main source of noise in high-gain FEL amplifiers. It may negatively affect several HG FEL applications ranging from single- to multi-stage HGHG FELs. SASE saturation also imposes a fundamental hard limit on the gain of an FEL amplifier in a coherent electron-cooling scheme. A novel active method for suppressing shot noise in relativistic electron beams by many orders-of-magnitude was recently proposed. While theoretically such strong suppression appears feasible, the performance and applicability of this novel method must be evaluated experimentally. Several practical questions about the proposed noise suppressor, such as 3D effects and/or sensitivity to the e-beam parameters also require experimental clarification. To do this, we propose here a proof-of-principle experiment using elements of the VISA FEL at BNL's Accelerator Test Facility.

Litvinenko,V.; Yakimenko, V.

2009-08-23

246

Early diagnostic paracentesis in spontaneous bacterial peritonitis.  

E-print Network

??Background: Spontaneous bacterial peritonitis (SBP) frequently occurs in hospitalized patients with cirrhosis and ascites and is associated with high mortality. Early paracentesis (EP) allows rapid… (more)

Kim, John J.

2011-01-01

247

High d(+)-fructose diet adversely affects testicular weight gain in weaning rats?protection by moderate d(+)-glucose diet.  

PubMed

The use of high D(+)-fructose corn syrup has increased over the past several decades in the developed countries, while overweight and obesity rates and the related diseases have risen dramatically. However, we found that feeding a high D(+)-fructose diet (80% D(+)-fructose as part of the diet) to weaning rats for 21 days led to reduced food intake (50% less, P < 0.0001) and thus delayed the weight gains in the body (40% less, P < 0.0001) and testes (40% less, P < 0.0001) compared to the no D(+)-fructose diet. We also challenged a minimum requirement of dietary D(+)-glucose for preventing the adverse effects of D(+)-fructose, such as lower food intake and reduction of body weight and testicular weight; the minimum requirement of D(+)-glucose was ?23% of the diet. This glucose amount may be the minimum requirement of exogenous glucose for reducing weight gain. PMID:23935370

Shibata, Katsumi; Fukuwatari, Tsutomu

2013-01-01

248

High D(+)-Fructose Diet Adversely Affects Testicular Weight Gain in Weaning Rats?Protection by Moderate D(+)-Glucose Diet  

PubMed Central

The use of high D(+)-fructose corn syrup has increased over the past several decades in the developed countries, while overweight and obesity rates and the related diseases have risen dramatically. However, we found that feeding a high D(+)-fructose diet (80% D(+)-fructose as part of the diet) to weaning rats for 21 days led to reduced food intake (50% less, P < 0.0001) and thus delayed the weight gains in the body (40% less, P < 0.0001) and testes (40% less, P < 0.0001) compared to the no D(+)-fructose diet. We also challenged a minimum requirement of dietary D(+)-glucose for preventing the adverse effects of D(+)-fructose, such as lower food intake and reduction of body weight and testicular weight; the minimum requirement of D(+)-glucose was ?23% of the diet. This glucose amount may be the minimum requirement of exogenous glucose for reducing weight gain. PMID:23935370

Shibata, Katsumi; Fukuwatari, Tsutomu

2013-01-01

249

Single crystalline Er2O3:sapphire films as potentially high-gain amplifiers at telecommunication wavelength  

NASA Astrophysics Data System (ADS)

Single crystalline thin films of Er2O3, demonstrating efficient 1.5 ?m luminescence of Er3+ at room temperature were grown on Al2O3 substrate by molecular beam epitaxy. The absorption coefficient at 1.536 ?m was found to reach 270 cm-1 translating in a maximal possible gain of 1390 dBcm-1. In conjunction with the 10% higher refractive index as compared to Al2O3, this opens the possibility to use Er2O3:sapphire films as short-length waveguide amplifiers in telecommunication.

Kuznetsov, A. S.; Sadofev, S.; Schäfer, P.; Kalusniak, S.; Henneberger, F.

2014-11-01

250

Improving proliferation resistance of high breeding gain generation 4 reactors using blankets composed of light water reactor waste  

SciTech Connect

Fertile blankets can be used in fast reactors to enhance the breeding gain as well as the passive safety characteristics. However, such blankets typically result in the production of weapons grade plutonium. For this reason they are often excluded from Generation IV reactor designs. In this paper we demonstrate that using blankets manufactured directly from spent light water (LWR) reactor fuel it is possible to produce a plutonium product with non-proliferation characteristics on a par with spent LWR fuel of 30-50 MWd/kg burnup. The beneficial breeding and safety characteristics are retained. (authors)

Hellesen, C.; Grape, S.; Haakanson, A.; Jacobson Svaerd, S.; Jansson, P. [Division of Applied Nuclear Physics, Uppsala University, Aangstroemlaboratoriet Laegerhyddsvaegen 1, 751 20 Uppsala (Sweden)

2013-07-01

251

Thermal noise analysis of multi-bit SC gain-stages for low-voltage high-resolution pipeline ADC design  

Microsoft Academic Search

Analysis of thermal noise in switched-capacitor multi-bit gain-stages used in low-voltage high-resolution pipeline analog-to-digital converters is presented. The analytical expression obtained for the input referred noise power, which should be considered in the design procedure, is general for any number of bits being resolved and shows that the noise power is decreased when more bits are resolved in the stage.

M. Y. Azizi; A. Saeedfar; H. Z. Hoseini; O. Shoaei

2003-01-01

252

Spontaneous Resolution of Pneumocystis jirovecii Pneumonia on High-Resolution Computed Tomography in a Patient with Renal Cell Carcinoma  

PubMed Central

Patient: Male, 59 Final Diagnosis: Pneumocystis jirovecii pneumonia Symptoms: Low grade fever Medication: — Clinical Procedure: Transbronchial lung biopsy Specialty: Pulmonology Objective: Rare disease Background: Spontaneous resolution of Pneumocystis jirovecii pneumonia has rarely been reported. Case Report: A 59-year-old man presented to our hospital because of pyrexia (38°C) and shaking chills for 2 days. He had a history of right nephrectomy due to renal cell carcinoma and left upper lobectomy for lung metastasis in the last 1.5 years. Two months previously, he was treated with oral prednisolone (20 mg/day) plus the intravenous mTOR inhibitor, temsirolimus (25 mg/week), for brain metastasis. On radiological examination, thoracic computed tomography showed diffuse ground glass opacities spreading in bilateral middle to lower lung fields. Although transbronchial biopsy specimens and bronchoalveolar lavage fluid demonstrated the presence of accumulation of black-colored Pneumocystis jirovecii cysts in the lung, his chief complaints and radiological abnormalities disappeared completely with no treatment. This case demonstrates a unique clinical presentation of Pneumocystis jirovecii pneumonia, in that spontaneous resolution was noted on clinical and sequential radiological evaluations. Conclusions: Increasing numbers of cytotoxic drugs and biological therapies have emerged, and changes in the immune status due to underlying diseases or administration of immunosuppressive drugs might affect the inflammatory process of Pneumocystis jirovecii pneumonia, as in the present case. PMID:25396336

Tanaka, Yasutaka; Saraya, Takeshi; Kurai, Daisuke; Ishii, Haruyuki; Takizawa, Hajime; Goto, Hajime

2014-01-01

253

A power efficient bandwidth regulation technique for a low-noise high-gain RF wideband amplifier  

NASA Astrophysics Data System (ADS)

In this paper, a single-stage deep sub-micron wideband amplifier (LNA) using a reactive resonance tank and passive port-matching techniques is demonstrated operating in the microwave frequency range (K band). A novel power-efficient bandwidth (BW) regulation technique is proposed by incorporating a small impedance in the resonance tank of the amplifier configuration. It manifests a forward gain in the range of 5.9-10.7 dB covering a message bandwidth of 10.6-6.3 GHz. With regulation, input-output reflection parameters ( S 11, S 22) and noise figure can be manipulated by -12.7 dB, -22.7 dB and 0.36 dB, respectively. Symmetric regulation is achieved for bandwidth and small signal gain with respect to moderate tank impedance (36.5% and -26.8%, respectively) but the effect on noise contribution remains relatively low (increase of 7% from a base value of 2.39 dB). The regulated architecture, when analyzed with 90 nm silicon CMOS process, supports low power (9.1 mW) on-chip communication. The circuit is tested with a number of combinations for tank (drain) impedance to verify the efficiency of the proposed technique and achieves better figures of merit when compared with published literature.

Roy, Apratim; Rashid, S. M. S.

2012-09-01

254

The effect of high [K(+)]o on spontaneous Ca(2+) waves in freshly isolated interstitial cells of Cajal from the rabbit urethra.  

PubMed

Interstitial cells of Cajal (ICC) act as putative pacemaker cells in the rabbit urethra. Pacemaker activity in ICC results from spontaneous global Ca(2+) waves that can be increased in frequency by raising external [K(+)]. The purpose of this study was to elucidate the mechanism of this response. Intracellular [Ca(2+)] was measured in fluo-4-loaded smooth muscle cells (SMCs) and ICC using a Nipkow spinning disk confocal microscope. Increasing [K(+)]o to 60 mmol/L caused an increase in [Ca(2+)]i accompanied by contraction in SMCs. Raising [K(+)]o did not cause contraction in ICC, but the frequency of firing of spontaneous calcium waves increased. Reducing [Ca(2+)]o to 0 mmol/L abolished the response in both cell types. Nifedipine of 1 ?mol/L blocked the response of SMC to high [K(+)]o, but did not affect the increase in firing in ICC. This latter effect was blocked by 30 ?mol/L NiCl2 but not by the T-type Ca(2+) channel blocker mibefradil (300 nmol/L). However, inhibition of Ca(2+) influx via reverse-mode sodium/calcium exchange (NCX) using either 1 ?mol/L SEA0400 or 5 ?mol/L KB-R7943 did block the effect of high [K(+)]o on ICC. These data suggest that high K(+) solution increases the frequency of calcium waves in ICC by increasing Ca(2+) influx through reverse-mode NCX. PMID:24744882

Drumm, Bernard T; Sergeant, Gerard P; Hollywood, Mark A; Thornbury, Keith T; Matsuda, Toshio T; Baba, Akemichi; Harvey, Brian J; McHale, Noel G

2014-01-01

255

The effect of high [K+]o on spontaneous Ca2+ waves in freshly isolated interstitial cells of Cajal from the rabbit urethra  

PubMed Central

Abstract Interstitial cells of Cajal (ICC) act as putative pacemaker cells in the rabbit urethra. Pacemaker activity in ICC results from spontaneous global Ca2+ waves that can be increased in frequency by raising external [K+]. The purpose of this study was to elucidate the mechanism of this response. Intracellular [Ca2+] was measured in fluo?4?loaded smooth muscle cells (SMCs) and ICC using a Nipkow spinning disk confocal microscope. Increasing [K+]o to 60 mmol/L caused an increase in [Ca2+]i accompanied by contraction in SMCs. Raising [K+]o did not cause contraction in ICC, but the frequency of firing of spontaneous calcium waves increased. Reducing [Ca2+]o to 0 mmol/L abolished the response in both cell types. Nifedipine of 1 ?mol/L blocked the response of SMC to high [K+]o, but did not affect the increase in firing in ICC. This latter effect was blocked by 30 ?mol/L NiCl2 but not by the T?type Ca2+ channel blocker mibefradil (300 nmol/L). However, inhibition of Ca2+ influx via reverse?mode sodium/calcium exchange (NCX) using either 1 ?mol/L SEA0400 or 5 ?mol/L KB?R7943 did block the effect of high [K+]o on ICC. These data suggest that high K+ solution increases the frequency of calcium waves in ICC by increasing Ca2+ influx through reverse?mode NCX. PMID:24744882

Drumm, Bernard T.; Sergeant, Gerard P.; Hollywood, Mark A.; Thornbury, Keith T.; Matsuda, Toshio T.; Baba, Akemichi; Harvey, Brian J.; McHale, Noel G.

2014-01-01

256

Characterization of semiconductor lasers by spontaneous emission measurements  

Microsoft Academic Search

The measurement of spontaneous emission is a powerful characterization technique of semiconductor lasers, which has been developed with the fabrication of the first lasers. It allows the determination of both material and structural parameters such as gain, refractive index, longitudinal effects, etc. Significant advance has been made recently on the understanding of material properties and lasing characteristics by using spontaneous

F. Girardin; Guang-Hua Duan

1997-01-01

257

Early metabolic adaptation in C57BL/6 mice resistant to high fat diet induced weight gain involves an activation of mitochondrial oxidative pathways.  

PubMed

We investigated the short-term (7 days) and long-term (60 days) metabolic effect of high fat diet induced obesity (DIO) and weight gain in isogenic C57BL/6 mice and examined the specific metabolic differentiation between mice that were either strong-responders (SR), or non-responders (NR) to weight gain. Mice (n = 80) were fed a standard chow diet for 7 days prior to randomization into a high-fat (HF) (n = 56) or a low-fat (LF) (n = 24) diet group. The (1)H NMR urinary metabolic profiles of LF and HF mice were recorded 7 and 60 days after the diet switch. On the basis of the body weight gain (BWG) distribution of HF group, we identified NR mice (n = 10) and SR mice (n = 14) to DIO. Compared with LF, HF feeding increased urinary excretion of glycine conjugates of ?-oxidation intermediate (hexanoylglycine), branched chain amino acid (BCAA) catabolism intermediates (isovalerylglycine, ?-keto-?-methylvalerate and ?-ketoisovalerate) and end-products of nicotinamide adenine dinucleotide (NAD) metabolism (N1-methyl-2-pyridone-5-carboxamide, N1-methyl-4-pyridone-3-carboxamide) suggesting up-regulation of mitochondrial oxidative pathways. In the HF group, NR mice excreted relatively more hexanoylglycine, isovalerylglycine, and fewer tricarboxylic acid (TCA) cycle intermediate (succinate) in comparison to SR mice. Thus, subtle regulation of ketogenic pathways in DIO may alleviate the saturation of the TCA cycle and mitochondrial oxidative metabolism. PMID:23473242

Boulangé, Claire L; Claus, Sandrine P; Chou, Chieh J; Collino, Sebastiano; Montoliu, Ivan; Kochhar, Sunil; Holmes, Elaine; Rezzi, Serge; Nicholson, Jeremy K; Dumas, Marc E; Martin, François-Pierre J

2013-04-01

258

NY-ESO-1 is highly expressed in poor-prognosis multiple myeloma and induces spontaneous humoral and cellular immune responses  

PubMed Central

The presence of a metaphase cytogenetic abnormality (CA) is the key negative predictor of outcome in patients with multiple myeloma (MM). Gene expression profiling (GEP) of such patients showed increased expression of NY-ESO-1 compared to patients with normal cytogenetics (60% versus 31%; P = .004). NY-ESO-1 was also highly expressed in relapsing MM especially patients with CA (100% versus 60.7%; P < .001). GEP findings were confirmed at the protein level by immunostaining of marrow biopsies for NY-ESO-1. We detected spontaneous NY-ESO-1–specific antibodies by enzyme-linked immunosorbent assay in 33% of patients with NY-ESO-1+ MM, especially in CA patients (9 of 13; 70%), but in none of the NY-ESO-1- patients with MM (n = 27) or healthy donors (n = 21). Spontaneous NY-ESO-1157-165–specific T cells (0.2%-0.6% of CD8+ T cells) were found in the peripheral blood of NY-ESO-1+ MM with HLA-A*0201/NY-ESO-1157-165 tetramers. These NY-ESO-1–specific T cells, when expanded, killed primary MM cells (50% lysis, effector-target [E/T] ratio, 10:1). Our data demonstrate that NY-ESO-1 is frequently expressed in MM with CA and is capable of eliciting spontaneous humoral and T-cell immunity. The pool of NY-ESO-1–specific cytotoxic T cells expands easily on NY-ESO-1 peptide stimulation and is functionally active. NY-ESO-1 should therefore be an ideal tumor target antigen for immunotherapy of patients with poor-prognosis MM. PMID:15671442

van Rhee, Frits; Szmania, Susann M.; Zhan, Fenghuang; Gupta, Sushil K.; Pomtree, Mindy; Lin, Pei; Batchu, Ramesh B.; Moreno, Amberly; Spagnoli, Guilio; Shaughnessy, John; Tricot, Guido

2005-01-01

259

Weight Gain during Pregnancy  

MedlinePLUS

... this page It's been added to your dashboard . Weight gain during pregnancy When you’re pregnant, you ... in sight! Be careful about the amount of weight you gain during your pregnancy. Gaining too much ...

260

Significant progression of load on the musculoskeletal system with extremely high loads, with rapid weekly weight gains, using the Anatoly Gravitational System, in a 10-week training period  

PubMed Central

In an age of increasing numbers of lifestyle diseases and plasticity of longevity, exercise and weight training have been increasingly recognized as both preventing and mitigating the severity of many illnesses. This study was designed to determine whether significant weight-lifting gains could be realized through the Anatoly Gravitational System. Specifically, this study sought to determine whether this once-weekly weight-training system could result in significant weekly strength gains during a 10-week training period. A total of 50 participants, ranging in age from 17 to 67 years, completed at least 10 weekly 30-minute training sessions. The results suggest participants could, on average, double their weight-lifting capacity within 10 sessions. This preliminary study, which would require further scrutiny, suggests the Anatoly Gravitational System provides a rather unique opportunity to load the musculoskeletal system with extremely high loads, with rapid weekly weight gains, using only short weekly training sessions. More studies are warranted to scrutinize these findings. PMID:24379727

Burke, David T; Tran, David; Cui, Di; Burke, Daniel P; Al-Adawi, Samir; Dorvlo, Atsu SS

2013-01-01

261

JUNGFRAU 0.2: prototype characterization of a gain-switching, high dynamic range imaging system for photon science at SwissFEL and synchrotrons  

NASA Astrophysics Data System (ADS)

JUNGFRAU (adJUstiNg Gain detector FoR the Aramis User station) is a two-dimensional pixel detector for photon science applications at free electron lasers and synchrotron light sources. It is developed for the SwissFEL currently under construction at the Paul Scherrer Institute, Switzerland. Characteristics of this application-specific integrating circuit readout chip include single photon sensitivity and low noise over a dynamic range of over four orders of magnitude of photon input signal. These characteristics are achieved by a three-fold gain-switching preamplifier in each pixel, which automatically adjusts its gain to the amount of charge deposited on the pixel. The final JUNGFRAU chip comprises 256 × 256 pixels of 75 × 75 ?m2 each. Arrays of 2 × 4 chips are bump-bonded to monolithic detector modules of about 4 × 8 cm2. Multi-module systems up to 16 Mpixels are planned for the end stations at SwissFEL. A readout rate in excess of 2 kHz is anticipated, which serves the readout requirements of SwissFEL and enables high count rate synchrotron experiments with a linear count rate capability of > 20 MHz/pixel. Promising characterization results from a 3.6 × 3.6 mm2 prototype (JUNGFRAU 0.2) with fluorescence X-ray, infrared laser and synchrotron irradiation are shown. The results include an electronic noise as low as 100 electrons root-mean-square, which enables single photon detection down to X-ray energies of about 2 keV. Noise below the Poisson fluctuation of the photon number and a linearity error of the pixel response of about 1% are demonstrated. First imaging experiments successfully show automatic gain switching. The edge spread function of the imaging system proves to be comparable in quality to single photon counting hybrid pixel detectors.

Jungmann-Smith, J. H.; Bergamaschi, A.; Cartier, S.; Dinapoli, R.; Greiffenberg, D.; Johnson, I.; Maliakal, D.; Mezza, D.; Mozzanica, A.; Ruder, Ch; Schaedler, L.; Schmitt, B.; Shi, X.; Tinti, G.

2014-12-01

262

High-Fat-Diet-Induced Weight Gain Ameliorates Bone Loss without Exacerbating A?PP Processing and Cognition in Female APP/PS1 Mice  

PubMed Central

Osteoporosis is negatively correlated with body mass, whereas both osteoporosis and weight loss occur at higher incidence during the progression of Alzheimer’s disease (AD) than the age-matched non-dementia individuals. Given that there is no evidence that being overweight is associated with AD-type cognitive dysfunction, we hypothesized that moderate weight gain might have a protective effect on the bone loss in AD without exacerbating cognitive dysfunction. In this study, feeding a high-fat diet (HFD, 45% calorie from fat) to female APP/PS1 transgenic mice, an AD animal model, induced weight gain. The bone mineral density, microarchitecture, and biomechanical properties of the femurs were then evaluated. The results showed that the middle-aged female APP/PS1 transgenic mice were susceptible to osteoporosis of the femoral bones and that weight gain significantly enhanced bone mass and mechanical properties. Notably, HFD was not detrimental to brain insulin signaling and A?PP processing, as well as to exploration ability and working, learning, and memory performance of the transgenic mice measured by T maze and Morris water maze, compared with the mice fed a normal-fat diet (10% calorie from fat). In addition, the circulating levels of leptin but not estradiol were remarkably elevated in HFD-treated mice. These results suggest that a body weight gain induced by the HFD feeding regimen significantly improved bone mass in female APP/PS1 mice with no detriments to exploration ability and spatial memory, most likely via the action of elevated circulating leptin. PMID:25152713

Peng, Yunhua; Liu, Jing; Tang, Ying; Liu, Jianshu; Han, Tingting; Han, Shujun; Li, Hua; Hou, Chen; Liu, Jiankang; Long, Jiangang

2014-01-01

263

Novel high-gain, improved-bandwidth, finned-ladder V-band Traveling-Wave Tube slow-wave circuit design  

NASA Technical Reports Server (NTRS)

The V-band frequency range of 59-64 GHz is a region of the millimeter-wave spectrum that has been designated for inter-satellite communications. As a first effort to develop a high-efficiency V-band Traveling-Wave Tube (TWT), variations on a ring-plane slow-wave circuit were computationally investigated to develop an alternative to the more conventional ferruled coupled-cavity circuit. The ring-plane circuit was chosen because of its high interaction impedance, large beam aperture, and excellent thermal dissipation properties. Despite these advantages, however, low bandwidth and high voltage requirements have, until now, prevented its acceptance outside the laboratory. In this paper, the three-dimensional electrodynamic simulation code MAFIA (solution of MAxwell's Equation by the Finite-Integration-Algorithm) is used to investigate methods of increasing the bandwidth and lowering the operating voltage of the ring-plane circuit. Calculations of frequency-phase dispersion, beam on-axis interaction impedance, attenuation and small-signal gain per wavelength were performed for various geometric variations and loading distributions of the ring-plane TWT slow-wave circuit. Based on the results of the variations, a circuit termed the finned-ladder TWT slow-wave circuit was designed and is compared here to the scaled prototype ring-plane and a conventional ferruled coupled-cavity TWT circuit over the V-band frequency range. The simulation results indicate that this circuit has a much higher gain, significantly wider bandwidth, and a much lower voltage requirement than the scaled ring-plane prototype circuit, while retaining its excellent thermal dissipation properties. The finned-ladder circuit has a much larger small-signal gain per wavelength than the ferruled coupled-cavity circuit, but with a moderate sacrifice in bandwidth.

Kory, Carol L.; Wilson, Jeffrey D.

1994-01-01

264

High-gain effects minimized at the ends of the anodes in position sensitive gas proportional counters for SSM on ASTROSAT  

NASA Astrophysics Data System (ADS)

The Scanning Sky Monitor (SSM) on ASTROSAT is a position-sensitive gas-filled proportional counter with a wide field of view. The science objective of SSM is to scan the sky to detect and locate transient X-ray sources in the outburst phase. The energy range of operation of SSM is 2.5 to 10 keV. Gas-filled proportional counters are known to have distorted electric fields at the ends of the anodes inside the detector. The electric field and hence the gas gain is different at the ends of the anodes compared to that of the central region. In SSM, the ends of the anode wires were found to have high electric field values and hence high gas gain initially. These effects had to be minimized as they would result in huge charge collection for incidence of highly energetic photons and charged particles, leading to probable discharge effects which would limit the life time of the detector. They also result in undesirable signals, the amplitude of which may not be proportional to the energy of the incident photon. In this paper, we discuss the technique which we use to reduce the field at the ends of the anodes in SSM detectors.

Ramadevi, M. C.; Babu, V. C.; Ashoka, B. N.; Seetha, S.

2014-12-01

265

IR gain monitor  

NASA Astrophysics Data System (ADS)

The gain of the IR channel of WFC3 will be measured using a series of internal flat fields. Using knowledge gained from ground testing and previous cycles, we propose to collect flat field ramps which will be used to create photon transfer curves and give a measure of the gain. This continues the strategy of last cycle's gain monitor, in proposal 13080.

Hilbert, Bryan

2013-10-01

266

Porcine adiponectin receptor 1 transgene resists high-fat/sucrose diet-induced weight gain, hepatosteatosis and insulin resistance in mice.  

PubMed

Adiponectin and its receptors have been demonstrated to play important roles in regulating glucose and lipid metabolism in mice. Obesity, type II diabetes and cardiovascular disease are highly correlated with down-regulated adiponectin signaling. In this study, we generated mice overexpressing the porcine Adipor1 transgene (pAdipor1) to study its beneficial effects in metabolic syndromes as expressed in diet-induced obesity, hepatosteatosis and insulin resistance. Wild-type (WT) and pAdipor1 transgenic mice were fed ad libitum with a standard chow diet (Chow) or a high-fat/sucrose diet (HFSD) for 24 weeks, beginning at 6 to 7 weeks of age. There were 12 mice per genetic/diet/sex group. When challenged with HFSD to induce obesity, the pAdipor1 transgenic mice resisted development of weight gain, hepatosteatosis and insulin resistance. These mice had lowered plasma adiponectin, triglyceride and glycerol concentrations compared to WT mice. Moreover, we found that (indicated by mRNA levels) fatty acid oxidation was enhanced in skeletal muscle and adipose tissue, and liver lipogenesis was inhibited. The pAdipor1 transgene also restored HFSD-reduced phosphoenolpyruvate carboxykinase 1 (Pck1) and glucose transporter 4 mRNA in the adipose tissues, implying that the increased Pck1 may promote glyceroneogenesis to reduce glucose intolerance and thus activate the flux of glyceride-glycerol to resist diet-induced weight gain in the adipose tissues. Taken together, we demonstrated that pAdipor1 can prevent diet-induced weight gain and insulin resistance. Our findings may provide potential therapeutic strategies for treating metabolic syndromes and obesity, such as treatment with an ADIPOR1 agonist or activation of Adipor1 downstream targets. PMID:24172199

Liu, Bing-Hsien; Lin, Yuan-Yu; Wang, Ya-Chin; Huang, Chao-Wei; Chen, Chih-Chien; Wu, Shinn-Chih; Mersmann, Harry J; Cheng, Winston T K; Ding, Shih-Torng

2013-01-01

267

Porcine Adiponectin Receptor 1 Transgene Resists High-fat/Sucrose Diet-Induced Weight Gain, Hepatosteatosis and Insulin Resistance in Mice  

PubMed Central

Adiponectin and its receptors have been demonstrated to play important roles in regulating glucose and lipid metabolism in mice. Obesity, type II diabetes and cardiovascular disease are highly correlated with down-regulated adiponectin signaling. In this study, we generated mice overexpressing the porcine Adipor1 transgene (pAdipor1) to study its beneficial effects in metabolic syndromes as expressed in diet-induced obesity, hepatosteatosis and insulin resistance. Wild-type (WT) and pAdipor1 transgenic mice were fed ad libitum with a standard chow diet (Chow) or a high-fat/sucrose diet (HFSD) for 24 weeks, beginning at 6 to 7 weeks of age. There were 12 mice per genetic/diet/sex group. When challenged with HFSD to induce obesity, the pAdipor1 transgenic mice resisted development of weight gain, hepatosteatosis and insulin resistance. These mice had lowered plasma adiponectin, triglyceride and glycerol concentrations compared to WT mice. Moreover, we found that (indicated by mRNA levels) fatty acid oxidation was enhanced in skeletal muscle and adipose tissue, and liver lipogenesis was inhibited. The pAdipor1 transgene also restored HFSD-reduced phosphoenolpyruvate carboxykinase 1 (Pck1) and glucose transporter 4 mRNA in the adipose tissues, implying that the increased Pck1 may promote glyceroneogenesis to reduce glucose intolerance and thus activate the flux of glyceride-glycerol to resist diet-induced weight gain in the adipose tissues. Taken together, we demonstrated that pAdipor1 can prevent diet-induced weight gain and insulin resistance. Our findings may provide potential therapeutic strategies for treating metabolic syndromes and obesity, such as treatment with an ADIPOR1 agonist or activation of Adipor1 downstream targets. PMID:24172199

Liu, Bing-Hsien; Lin, Yuan-Yu; Wang, Ya-Chin; Huang, Chao-Wei; Chen, Chih-Chien; Wu, Shinn-Chih; Mersmann, Harry J.; Cheng, Winston T.K.; Ding, Shih-Torng

2013-01-01

268

Gathering Feedback for Teaching: Combining High-Quality Observations with Student Surveys and Achievement Gains. Research Paper. MET Project  

ERIC Educational Resources Information Center

There is a growing consensus that teacher evaluation in the United States is fundamentally broken. Few would argue that a system that tells 98 percent of teachers they are "satisfactory" benefits anyone--including teachers. The nation's collective failure to invest in high-quality professional feedback to teachers is inconsistent with decades of…

Kane, Thomas J.; Staiger, Douglas O.

2012-01-01

269

Three Months of High-Fructose Feeding Fails to Induce Excessive Weight Gain or Leptin Resistance in Mice  

PubMed Central

High-fructose diets have been implicated in obesity via impairment of leptin signaling in humans and rodents. We investigated whether fructose-induced leptin resistance in mice could be used to study the metabolic consequences of fructose consumption in humans, particularly in children and adolescents. Male C57Bl/6 mice were weaned to a randomly assigned diet: high fructose, high sucrose, high fat, or control (sugar-free, low-fat). Mice were maintained on their diets for at least 14 weeks. While fructose-fed mice regularly consumed more kcal and expended more energy, there was no difference in body weight compared to control by the end of the study. Additionally, after 14 weeks, both fructose-fed and control mice displayed similar leptin sensitivity. Fructose-feeding also did not change circulating glucose, triglycerides, or free fatty acids. Though fructose has been linked to obesity in several animal models, our data fail to support a role for fructose intake through food lasting 3 months in altering of body weight and leptin signaling in mice. The lack of impact of fructose in the food of growing mice on either body weight or leptin sensitivity over this time frame was surprising, and important information for researchers interested in fructose and body weight regulation. PMID:25211467

Tillman, Erik J.; Morgan, Donald A.; Rahmouni, Kamal; Swoap, Steven J.

2014-01-01

270

How Much Professional Development Is Needed to Effect Positive Gains in K-6 Student Achievement on High Stakes Science Tests?  

ERIC Educational Resources Information Center

This paper is a report of a study that examines the relationship between teacher participation in a multi-year, K-6 professional development effort and the "high stakes" science test scores of different student groups in 33 rural mid-west school districts in the USA. The professional development program involved 1,269 elementary school teachers…

Shymansky, James A.; Wang, Tzu-Ling; Annetta, Leonard A.; Yore, Larry D.; Everett, Susan A.

2012-01-01

271

High thallus water content severely limits photosynthetic carbon gain of central European epilithic lichens under natural conditions  

Microsoft Academic Search

Experiments under controlled conditions have shown that net photosynthesis (NP) of many lichens is depressed when their thalli are highly hydrated. In this study we characterise the light and water content (WC) dependency of CO2 exchange for selected epilithic lichens in the laboratory and match this against samples monitored in their natural habitat by a novel, fully automatic cuvette. Laboratory

Otto L. Lange; T. G. Allan Green

1996-01-01

272

Prediction of Spontaneous Preterm Birth  

Microsoft Academic Search

Preterm birth is a leading cause of neonatal morbidity and mortality. It is a major goal in obstetrics to lower the incidence of spontaneous preterm birth (SPB) and related neonatal morbidity and mortality. One of the principal objectives is to discover early markers that would allow us to identify subgroups of patients at high risk of SPB and, secondly, to

Karolien Dijkstra

2002-01-01

273

METHYLPHENIDATE AND ATOMOXETINE TREATMENT DURING ADOLESCENCE IN THE SPONTANEOUSLY HYPERTENSIVE RAT: MECHANISMS UNDERLYING HIGH COCAINE ABUSE LIABILITY IN ATTENTION DEFICIT/HYPERACTIVITY DISORDER.  

E-print Network

??Effects of pharmacotherapies for Attention Deficit/Hyperactivity Disorder (ADHD) on cocaine abuse liability in ADHD are not understood. Spontaneously Hypertensive Rats (SHR), an ADHD model, exhibited… (more)

Somkuwar, Sucharita S.

2013-01-01

274

Spontaneous EEG activity and spontaneous emotion regulation.  

PubMed

Variability in both frontal and parietal spontaneous EEG activity, using ? and ? band power and ?/? and ?/? ratios, was explored in a sample of 96 healthy volunteers as a potential correlate of individual differences in spontaneous emotion regulation (SER). Following a baseline EEG recording, participants were asked to continuously rate their discomfort while looking at affective pictures, as well as for a period of time after exposure. Greater spontaneous ? band power in parietal locations, lower frontal and parietal ?/? ratios, and lower parietal ?/? ratio were associated with lower ratings of discomfort after the offset of unpleasant pictures. Moreover, lower parietal ?/? ratio was also related to less time needed to recover from discomfort after exposure to aversive pictures, while only a greater frontal and parietal ? band power appeared to be associated with faster recovery from discomfort induced by normative-neutral pictures. However, parietal ?/? ratio was the only predictor of both minimum discomfort ratings and time needed to downregulate following exposure to unpleasant pictures, and frontal ? band power the only spontaneous EEG index that predicted variability in spontaneous down-regulation after the exposure to normative-neutral pictures. Results are discussed focusing on the utility of diverse spontaneous EEG measures in several cortical regions when capturing trait-like individual differences in emotion regulation capabilities and processes. PMID:25219892

Tortella-Feliu, M; Morillas-Romero, A; Balle, M; Llabrés, J; Bornas, X; Putman, P

2014-12-01

275

Normal Distribution of Body Weight Gain in Male Sprague-Dawley Rats Fed a High-Energy Diet  

Microsoft Academic Search

Objective: To investigate the effect of a high-energy (HE) diet on caloric intake, body weight, and related parameters in outbred male Sprague-Dawley (SD) rats.Research Methods and Procedures: Twenty-eight SD rats were fed either chow (C) for 19 weeks or HE diet for 14 weeks and then C for 5 weeks. Blood hormones and metabolites were assayed, and expression of uncoupling

Zoe A. Archer; D. Vernon Rayner; Jan Rozman; Martin Klingenspor; Julian G. Mercer

2003-01-01

276

Kinetic and Thermodynamic Analyses of Spontaneous Exchange between High-Density Lipoprotein-Bound and Lipid-Free Apolipoprotein A-I.  

PubMed

It is thought that apolipoprotein A-I (apoA-I) spontaneously exchanges between high-density lipoprotein (HDL)-bound and lipid-free states, which is relevant to the occurrence of pre?-HDL particles in plasma. To improve our understanding of the mechanistic basis for this phenomenon, we performed kinetic and thermodynamic analyses for apoA-I exchange between discoidal HDL-bound and lipid-free forms using fluorescence-labeled apoA-I variants. Gel filtration experiments demonstrated that addition of excess lipid-free apoA-I to discoidal HDL particles promotes exchange of apoA-I between HDL-associated and lipid-free pools without alteration of the steady-state HDL particle size. Kinetic analysis of time-dependent changes in NBD fluorescence upon the transition of NBD-labeled apoA-I from HDL-bound to lipid-free state indicates that the exchange kinetics are independent of the collision frequency between HDL-bound and lipid-free apoA-I, in which the lipid binding ability of apoA-I affects the rate of association of lipid-free apoA-I with the HDL particles and not the rate of dissociation of HDL-bound apoA-I. Thus, C-terminal truncations or mutations that reduce the lipid binding affinity of apoA-I strongly impair the transition of lipid-free apoA-I to the HDL-bound state. Thermodynamic analysis of the exchange kinetics demonstrated that the apoA-I exchange process is enthalpically unfavorable but entropically favorable. These results explain the thermodynamic basis of the spontaneous exchange reaction of apoA-I associated with HDL particles. The altered exchangeability of dysfunctional apoA-I would affect HDL particle rearrangement, leading to perturbed HDL metabolism. PMID:25564321

Handa, Daisuke; Kimura, Hitoshi; Oka, Tatsuya; Takechi, Yuki; Okuhira, Keiichiro; Phillips, Michael C; Saito, Hiroyuki

2015-02-01

277

High Magnetic Shear Gain in a Liquid Sodium Stable Couette Flow Experiment: A Prelude to an {alpha}-{Omega} Dynamo  

SciTech Connect

The {Omega} phase of the liquid sodium {alpha}-{Omega} dynamo experiment at New Mexico Institute of Mining and Technology in cooperation with Los Alamos National Laboratory has demonstrated a high toroidal field B{sub {phi}} that is {approx_equal}8xB{sub r}, where B{sub r} is the radial component of an applied poloidal magnetic field. This enhanced toroidal field is produced by the rotational shear in stable Couette flow within liquid sodium at a magnetic Reynolds number Rm{approx_equal}120. Small turbulence in stable Taylor-Couette flow is caused by Ekman flow at the end walls, which causes an estimated turbulence energy fraction of ({delta}v/v){sup 2{approx}}10{sup -3}.

Colgate, Stirling A. [T-2, MS B-227, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Department of Physics, New Mexico Institute of Mining and Technology, Socorro, New Mexico 87801 (United States); Beckley, Howard; Si, Jiahe; Martinic, Joe; Westpfahl, David; Slutz, James; Westrom, Cebastian; Klein, Brianna; Schendel, Paul; Scharle, Cletus; McKinney, Travis; Ginanni, Rocky; Bentley, Ian; Mickey, Timothy; Ferrel, Regnar [Department of Physics, New Mexico Institute of Mining and Technology, Socorro, New Mexico 87801 (United States); Li, Hui; Pariev, Vladimir [T-2, MS B-227, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Finn, John [T-5, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2011-04-29

278

New insights into hydrochemical processes in lowland river systems gained from in situ, high-resolution monitoring  

NASA Astrophysics Data System (ADS)

This work focuses on the insights obtained from in situ, high-resolution hydrochemical monitoring in three lowland UK catchments experiencing different levels of nutrient enrichment. Between November 2009 and February 2012, the upper River Kennet, the River Enborne and The Cut, all located within the Thames basin, southeast England, were instrumented with in situ analytical equipment to make hourly measurements of a range of hydrochemical determinands. The upper River Kennet is a rural catchment with limited effluent inputs above the selected monitoring point. The River Enborne is a rural catchment, impacted by agricultural runoff, and septic tank and sewage treatment works (STWs) discharges. The Cut is a highly urbanised system significantly affected by STW discharges. On the upper River Kennet and the River Enborne hourly measurements of Total Reactive Phosphorus (TRP) were made using a Systea Micromac C. In addition on the River Enborne, a Hach Lange Nitratax was used to measure nitrate (NO3). On The Cut both Total P and TRP were measured using a Hach Lange Phosphax Sigma. At all stations nutrient monitoring was supplemented with hourly pH, chlorophyll, dissolved oxygen, conductivity, turbidity and water temperature using YSI 6600 Multi-parameter sondes. Instream hydrochemical dynamics were investigated using non-stationary time-series analysis techniques. The results reveal complex nutrient dynamics, with diurnal patterns which exhibit seasonal changes in phase and amplitude, and are influenced by flow conditions, shading and nutrient sources. On the River Enborne a marked diurnal cycle was present within the streamwater NO3 time-series. The cycle was strongest in the spring before riparian shading developed. At times of low flow a two peak diurnal cycle was also evident in the streamwater NO3 time-series. The reduction in diurnal NO3 processing after the development of riparian shading was also accompanied by a marked drop in dissolved oxygen at this time. The presence of a two peak diurnal cycle is indicative of the dominance of STW discharges to the system, as STW discharges exhibit a marked two peak diurnal cycle associated with peak water usage. This two peak diurnal cycling can also been seen in the River Enborne TRP data. The dominance of effluent discharges was also evident in the River Enborne seasonal NO3 and TRP dynamics. Both determinands displayed summer time peaks caused by the reduced dilution capacity of the system and increased water residence time during the low flow summer months. The TP and TRP dynamics on The Cut were highly complex with significant diurnal fluctuations. Although, a two peak diurnal signal was evident within the TRP time-series it was difficult to characterise due to the complexity of the dynamics observed. Monitoring on the upper River Kennet highlighted the challenges associated with undertaking in situ analytical monitoring without mains electricity. Resampling of the data at lower sampling frequencies demonstrated that within the point-source dominated catchments, daily monitoring was sufficient for accurate load estimation.

Wade, Andrew; Palmer-Felgate, Elizabeth; Halliday, Sarah; Skeffington, Richard; Loewenthal, Matthew; Jarvie, Helen; Bowes, Michael; Greenway, Gillian; Haswell, Stephen; Bell, Ian; Joly, Etienne; Fallatah, Ahmed; Neal, Colin; Williams, Richard; Gozzard, Emma; Newman, Jonathan

2013-04-01

279

Removing environmental sources of variation to gain insight on symbionts vs. transient microbes in high and low microbial abundance sponges.  

PubMed

In this study, we pursue unravelling the bacterial communities of 26 sponges, belonging to several taxonomical orders, and comprising low microbial abundance (LMA) and high microbial abundance (HMA) representatives. Particularly, we searched for species-specific bacteria, which could be considered as symbionts. To reduce temporal and spatial environmentally caused differences between host species, we sampled all the sponge species present in an isolated small rocky area in a single dive. The bacterial communities identified by pyrosequencing the 16S rRNA gene showed that all HMA species clustered separated from LMA sponges and seawater. HMA sponges often had highest diversity, but some LMA sponges had also very diverse bacterial communities. Network analyses indicated that no core bacterial community seemed to exist for the studied sponges, not even for such a space and time-restricted sampling. Most sequences, particularly the most abundant ones in each species, were species-specific for both HMA and LMA sponges. The bacterial sequences retrieved from LMA sponges, despite being phylogenetically more similar to seawater, did not represent transient seawater bacteria. We conclude that sponge bacterial communities depend more on the host affiliation to the HMA or LMA groups than on host phylogeny. PMID:24118834

Blanquer, Andrea; Uriz, Maria J; Galand, Pierre E

2013-08-30

280

Optical automatic gain channel  

NASA Technical Reports Server (NTRS)

Automatic Gain Control /AGC/ channel automatically compensates for gain changes in the azimuth error channel due to time varying optical sight degrading effects. This system is useful in remote television monitors, automatic navigation systems, and surveying and mapping instrumentation.

Mrus, G.; Zukowsky, W.

1966-01-01

281

Spectral gain measurements of quantum confined emitters, and design and fabrication of intersubband quantum box laser structures  

NASA Astrophysics Data System (ADS)

Semiconductor laser active regions are commonly characterized by photo- and electro-luminescence (PL, EL) and cavity length analysis. However quantitative spectral information is not readily extracted from PL and EL data and comparison of different active region materials can be difficult. More quantifiable spectral information is contained in the optical gain spectra. This work reports on spectral gain studies, using multi-segmented interband devices, of InGaAs quantum well and quantum dot active regions grown by metalorganic chemical vapor deposition (MOCVD). Using the fundamental connection between gain and spontaneous emission spectra, the spontaneous radiative current and spontaneous radiative efficiency is evaluated for these active regions. The spectral gain and spontaneous radiative efficiency measurements of 980 nm emitting InGaAs quantum well (QW) material provides a benchmark comparison to previous results obtained on highly-strained, 1200 nm emitting InGaAs QW material. These studies provide insight into carrier recombination and the role of the current injection efficiency in InGaAs QW lasers. The spectral gain of self-assembled MOCVD grown InGaAs quantum dots (QD) active regions are also investigated, allowing for comparison to InGaAs QW material. The second part of my talk will cover intersubband-transition QW and quantum-box (QB) lasers. Quantum cascade (QC) lasers have emerged as compact and technologically important light sources in the mid-infrared (IR) and far-IR wavelength ranges infringing on the near-IR and terahertz spectral regions respectively. However, the overall power conversion efficiency, so-called wallplug efficiency, of the best QC lasers, emitting around 5 microns, is ˜9% in CW operation and very unlikely to exceed 15%. In order to dramatically improve the wallplug efficiency of mid-IR lasers (i.e., to about 50%), intersubband QB (IQB) lasers have been proposed. The basic idea, the optimal design and the progress towards the fabrication of IQB lasers will be presented.

Tsvid, Gene

282

Gain measurement of high characteristic temperature 1.3 micron GaInAsP\\/InP strained-layer quantum well lasers with Temperature Dependent Reflectivity (TDR) mirror  

Microsoft Academic Search

By comparing the optical gain of 1.3 micron strained-layer quantum well lasers with characteristic temperatures T(sub 0) of 150 K (high) and 60 K (typical), it is found that temperature insensitive net gain plays an important role in reducing the temperature sensitivity of the threshold current. The resonance frequency for high T(sub 0) lasers exhibits temperature insensitivity, resulting from the

A. Kasukawa; N. Iwai; N. Yamanaka; A. Hosotani; N. Yokouchi

1995-01-01

283

Exercise Prevents Weight Gain and Alters the Gut Microbiota in a Mouse Model of High Fat Diet-Induced Obesity  

PubMed Central

Background Diet-induced obesity (DIO) is a significant health concern which has been linked to structural and functional changes in the gut microbiota. Exercise (Ex) is effective in preventing obesity, but whether Ex alters the gut microbiota during development with high fat (HF) feeding is unknown. Objective Determine the effects of voluntary Ex on the gastrointestinal microbiota in LF-fed mice and in HF-DIO. Methods Male C57BL/6 littermates (5 weeks) were distributed equally into 4 groups: low fat (LF) sedentary (Sed) LF/Sed, LF/Ex, HF/Sed and HF/Ex. Mice were individually housed and LF/Ex and HF/Ex cages were equipped with a wheel and odometer to record Ex. Fecal samples were collected at baseline, 6 weeks and 12 weeks and used for bacterial DNA isolation. DNA was subjected both to quantitative PCR using primers specific to the 16S rRNA encoding genes for Bacteroidetes and Firmicutes and to sequencing for lower taxonomic identification using the Illumina MiSeq platform. Data were analyzed using a one or two-way ANOVA or Pearson correlation. Results HF diet resulted in significantly greater body weight and adiposity as well as decreased glucose tolerance that were prevented by voluntary Ex (p<0.05). Visualization of Unifrac distance data with principal coordinates analysis indicated clustering by both diet and Ex at week 12. Sequencing demonstrated Ex-induced changes in the percentage of major bacterial phyla at 12 weeks. A correlation between total Ex distance and the ?Ct Bacteroidetes: ?Ct Firmicutes ratio from qPCR demonstrated a significant inverse correlation (r2?=?0.35, p?=?0.043). Conclusion Ex induces a unique shift in the gut microbiota that is different from dietary effects. Microbiota changes may play a role in Ex prevention of HF-DIO. PMID:24670791

Evans, Christian C.; LePard, Kathy J.; Kwak, Jeff W.; Stancukas, Mary C.; Laskowski, Samantha; Dougherty, Joseph; Moulton, Laura; Glawe, Adam; Wang, Yunwei; Leone, Vanessa; Antonopoulos, Dionysios A.; Smith, Dan; Chang, Eugene B.; Ciancio, Mae J.

2014-01-01

284

A mitochondrial-targeted coenzyme q analog prevents weight gain and ameliorates hepatic dysfunction in high-fat-fed mice.  

PubMed

We hypothesized that the mitochondrial-targeted antioxidant, mitoquinone (mitoQ), known to have mitochondrial uncoupling properties, might prevent the development of obesity and mitigate liver dysfunction by increasing energy expenditure, as opposed to reducing energy intake. We administered mitoQ or vehicle (ethanol) to obesity-prone C57BL/6 mice fed high-fat (HF) or normal-fat (NF) diets. MitoQ (500 µM) or vehicle (ethanol) was added to the drinking water for 28 weeks. MitoQ significantly reduced total body mass and fat mass in the HF-fed mice but had no effect on these parameters in NF mice. Food intake was reduced by mitoQ in the HF-fed but not in the NF-fed mice. Average daily water intake was reduced by mitoQ in both the NF- and HF-fed mice. Hypothalamic expression of neuropeptide Y, agouti-related peptide, and the long form of the leptin receptor were reduced in the HF but not in the NF mice. Hepatic total fat and triglyceride content did not differ between the mitoQ-treated and control HF-fed mice. However, mitoQ markedly reduced hepatic lipid hydroperoxides and reduced circulating alanine aminotransferase, a marker of liver function. MitoQ did not alter whole-body oxygen consumption or liver mitochondrial oxygen utilization, membrane potential, ATP production, or production of reactive oxygen species. In summary, mitoQ added to drinking water mitigated the development of obesity. Contrary to our hypothesis, the mechanism involved decreased energy intake likely mediated at the hypothalamic level. MitoQ also ameliorated HF-induced liver dysfunction by virtue of its antioxidant properties without altering liver fat or mitochondrial bioenergetics. PMID:25301169

Fink, Brian D; Herlein, Judith A; Guo, Deng Fu; Kulkarni, Chaitanya; Weidemann, Benjamin J; Yu, Liping; Grobe, Justin L; Rahmouni, Kamal; Kerns, Robert J; Sivitz, William I

2014-12-01

285

Spaceliner Class Operability Gains Via Combined Airbreathing/ Rocket Propulsion: Summarizing an Operational Assessment of Highly Reusable Space Transports  

NASA Technical Reports Server (NTRS)

In discussing a new NASA initiative in advanced space transportation systems and technologies, the Director of the NASA Marshall Space Flight Center, Arthur G. Stephenson, noted that, "It would use new propulsion technology, air-breathing engine so you don't have to carry liquid oxygen, at least while your flying through the atmosphere. We are calling it Spaceliner 100 because it would be 100 times cheaper, costing $ 100 dollars a pound to orbit." While airbreathing propulsion is directly named, rocket propulsion is also implied by, "... while you are flying through the atmosphere." In-space final acceleration to orbital speed mandates rocket capabilities. Thus, in this informed view, Spaceliner 100 will be predicated on combined airbreathing/rocket propulsion, the technical subject of this paper. Interestingly, NASA's recently concluded Highly Reusable Space Transportation (HRST) study focused on the same affordability goal as that of the Spaceliner 100 initiative and reflected the decisive contribution of combined propulsion as a way of expanding operability and increasing the design robustness of future space transports, toward "aircraft like" capabilities. The HRST study built on the Access to Space Study and the Reusable Launch Vehicle (RLV) development activities to identify and characterize space transportation concepts, infrastructure and technologies that have the greatest potential for reducing delivery cost by another order of magnitude, from $1,000 to $100-$200 per pound for 20,000 lb. - 40.000 lb. payloads to low earth orbit (LEO). The HRST study investigated a number of near-term, far-term, and very far-term launch vehicle concepts including all-rocket single-stage-to-orbit (SSTO) concepts, two-stage-to-orbit (TSTO) concepts, concepts with launch assist, rocket-based combined cycle (RBCC) concepts, advanced expendable vehicles, and more far term ground-based laser powered launchers. The HRST study consisted of preliminary concept studies, assessments and analysis tool development for advanced space transportation systems, followed by end-to-end system concept definitions and trade analyses, specific system concept definition and analysis, specific key technology and topic analysis, system, operational and economics model development, analysis, and integrated assessments. The HRST Integration Task Force (HITF) was formed to synthesize study results in several specific topic areas and support the development of conclusions from the study: Systems Concepts Definitions, Technology Assessment, Operations Assessment, and Cost Assessment. This paper summarizes the work of the Operations Assessment Team: the six approaches used, the analytical tools and methodologies developed and employed, the issues and concerns, and the results of the assessment. The approaches were deliberately varied in measures of merit and procedure to compensate for the uncertainty inherent in operations data in this early phase of concept exploration. In general, rocket based combined cycle (RBCC) concepts appear to have significantly greater potential than all-rocket concepts for reducing operations costs.

Nix, Michael B.; Escher, William J. d.

1999-01-01

286

Wideband and high-gain frequency stabilization of a 100-W injection-locked Nd:YAG laser for second-generation gravitational wave detectors.  

PubMed

Second-generation gravitational wave detectors require a highly stable laser with an output power greater than 100 W to attain their target sensitivity. We have developed a frequency stabilization system for a 100-W injection-locked Nd:YAG (yttrium aluminum garnet) laser. By placing an external wideband electro-optic modulator used as a fast-frequency actuator in the optical path of the slave output, we can circumvent a phase delay in the frequency control loop originating from the pole of an injection-locked slave cavity. Thus, we have developed an electro-optic modulator made of a MgO-doped stoichiometric LiNbO(3) crystal. Using this modulator, we achieve a frequency control bandwidth of 800 kHz and a control gain of 180 dB at 1 kHz. These values satisfy the requirement for a laser frequency control loop in second-generation gravitational wave detectors. PMID:20687703

Ohmae, Noriaki; Moriwaki, Shigenori; Mio, Norikatsu

2010-07-01

287

Wideband and high-gain frequency stabilization of a 100-W injection-locked Nd:YAG laser for second-generation gravitational wave detectors  

NASA Astrophysics Data System (ADS)

Second-generation gravitational wave detectors require a highly stable laser with an output power greater than 100 W to attain their target sensitivity. We have developed a frequency stabilization system for a 100-W injection-locked Nd:YAG (yttrium aluminum garnet) laser. By placing an external wideband electro-optic modulator used as a fast-frequency actuator in the optical path of the slave output, we can circumvent a phase delay in the frequency control loop originating from the pole of an injection-locked slave cavity. Thus, we have developed an electro-optic modulator made of a MgO-doped stoichiometric LiNbO3 crystal. Using this modulator, we achieve a frequency control bandwidth of 800 kHz and a control gain of 180 dB at 1 kHz. These values satisfy the requirement for a laser frequency control loop in second-generation gravitational wave detectors.

Ohmae, Noriaki; Moriwaki, Shigenori; Mio, Norikatsu

2010-07-01

288

Consumption of a high-fat diet abrogates inhibitory effects of methylseleninic acid on spontaneous metastasis of Lewis lung carcinoma in mice.  

PubMed

We investigated the effect of dietary supplementation with selenium on spontaneous metastasis of Lewis lung carcinoma in mice fed a high-fat diet. Mice were fed a low-fat diet or that diet modified with 45% of calories from corn oil and supplemented with 0 or 2.5mg selenium/4029 kcal as methylseleninic acid. After 6 weeks, mice were each injected 2.5 × 10(5) Lewis lung carcinoma cells subcutaneously. The resulting primary tumor was removed surgically 10 days later; the experiment was terminated after an additional 10 days. High-fat feeding increased pulmonary metastases by 17% compared to the low-fat diet (P < 0.01). Selenium supplementation reduced the metastases by 11% compared to nonsupplemented controls (P < 0.05); the reduction was less for animals fed the high-fat diet (5%) than for those fed the low-fat diet (18%). Supplemental Se lowered plasma concentrations of proteases (urokinase plasminogen activator, P < 0.01; matrix metalloproteinase-9, P < 0.05) and angiogenic factors (vascular endothelial growth factor, P < 0.01; tissue inhibitor of metalloproteinase-1, P < 0.01) compared to nonsupplemented controls. High-fat feeding increased plasma concentrations of adipokines plasminogen activator inhibitor-1, monocyte chemotactic protein-1, tumor necrosis factor-?, and leptin regardless of the level of dietary selenium; supplemental selenium lowered plasma concentrations of plasminogen activator inhibitor-1 (P ? 0.05) and monocyte chemotactic protein-1 (P ? 0.05) in low-fat fed mice but not in high-fat fed mice. These results indicate that consumption of a high-fat diet abrogated the antimetastatic effects of selenium by increasing the expression of adipose-derived inflammatory cytokines. PMID:25053624

Yan, Lin; Combs, Gerald F

2014-10-01

289

Deletion of Tis7 protects mice from high-fat diet-induced weight gain and blunts the intestinal adaptive response postresection.  

PubMed

After loss of intestinal surface area, the remaining bowel undergoes a morphometric and functional adaptive response. Enterocytic expression of the transcriptional coregulator tetradecanoyl phorbol acetate induced sequence 7 (Tis7) is markedly increased in a murine model of intestinal adaptation. Mice overexpressing Tis7 in intestine have greater triglyceride absorption and weight gain when fed a high-fat diet (42% energy) than their wild-type (WT) littermates fed the same diet. These and other data suggest that Tis7 has a unique role in nutrient absorptive and metabolic adaptation. Herein, male Tis7(-/-) and WT mice were fed a high-fat diet (42% energy) for 8 wk. Weight was monitored and metabolic analyses and hepatic and intestinal lipid concentrations were compared after 8 wk. Intestinal lipid absorption and metabolism studies and intestinal resection surgeries were performed in separate groups of Tis7(-/-) and WT mice. At 8 wk, weight gain was less and jejunal mucosal and hepatic triglyceride and cholesterol concentrations were lower in Tis7(-/-) mice than in the WT controls. Following corn oil gavage, serum cholesterol, triglyceride, and FFA concentrations were lower in the Tis7(-/-) mice than in the WT mice. Incorporation of oral (3)[H] triolein into intestinal mucosal cholesterol ester and FFA was less in Tis7(-/-) compared with WT mice. Following resection, crypt cell proliferation rates and villus heights were lower in Tis7(-/-) than in WT mice, indicating a blunted adaptive response. Our results suggest a novel physiologic function for Tis7 in the gut as a global regulator of lipid absorption and metabolism and epithelial cell proliferation. PMID:20861213

Yu, Cong; Jiang, Shujun; Lu, Jianyun; Coughlin, Carrie C; Wang, Yuan; Swietlicki, Elzbieta A; Wang, Lihua; Vietor, Ilja; Huber, Lukas A; Cikes, Domagoj; Coleman, Trey; Xie, Yan; Semenkovich, Clay F; Davidson, Nicholas O; Levin, Marc S; Rubin, Deborah C

2010-11-01

290

Deletion of Tis7 Protects Mice from High-Fat Diet-Induced Weight Gain and Blunts the Intestinal Adaptive Response Postresection123  

PubMed Central

After loss of intestinal surface area, the remaining bowel undergoes a morphometric and functional adaptive response. Enterocytic expression of the transcriptional coregulator tetradecanoyl phorbol acetate induced sequence 7 (Tis7) is markedly increased in a murine model of intestinal adaptation. Mice overexpressing Tis7 in intestine have greater triglyceride absorption and weight gain when fed a high-fat diet (42% energy) than their wild-type (WT) littermates fed the same diet. These and other data suggest that Tis7 has a unique role in nutrient absorptive and metabolic adaptation. Herein, male Tis7?/? and WT mice were fed a high-fat diet (42% energy) for 8 wk. Weight was monitored and metabolic analyses and hepatic and intestinal lipid concentrations were compared after 8 wk. Intestinal lipid absorption and metabolism studies and intestinal resection surgeries were performed in separate groups of Tis7?/? and WT mice. At 8 wk, weight gain was less and jejunal mucosal and hepatic triglyceride and cholesterol concentrations were lower in Tis7?/? mice than in the WT controls. Following corn oil gavage, serum cholesterol, triglyceride, and FFA concentrations were lower in the Tis7?/? mice than in the WT mice. Incorporation of oral 3[H] triolein into intestinal mucosal cholesterol ester and FFA was less in Tis7?/? compared with WT mice. Following resection, crypt cell proliferation rates and villus heights were lower in Tis7?/? than in WT mice, indicating a blunted adaptive response. Our results suggest a novel physiologic function for Tis7 in the gut as a global regulator of lipid absorption and metabolism and epithelial cell proliferation. PMID:20861213

Yu, Cong; Jiang, Shujun; Lu, Jianyun; Coughlin, Carrie C.; Wang, Yuan; Swietlicki, Elzbieta A.; Wang, Lihua; Vietor, Ilja; Huber, Lukas A.; Cikes, Domagoj; Coleman, Trey; Xie, Yan; Semenkovich, Clay F.; Davidson, Nicholas O.; Levin, Marc S.; Rubin, Deborah C.

2010-01-01

291

Whey-reduced weight gain is associated with a temporary growth reduction in young mice fed a high-fat diet.  

PubMed

Whey protein consumption reportedly alleviates parameters of the metabolic syndrome. Here, we investigated the effects of whey protein isolate (whey) in young mice fed a high-fat diet. We hypothesized that whey as the sole protein source reduced early weight gain associated with retarded growth and decreased concentration of insulin-like growth factor-1. Moreover, we hypothesized that these changes were explained by increased nitrogen loss via elevated urea production and/or increased energy expenditure. Male 5-week-old C57BL/6 mice were fed high-fat diets with the protein source being either whey, casein or a combination of both for 5 weeks. After 1, 3 or 5 weeks, respectively, the mice were subjected to a meal challenge with measurements of blood and urinary urea before and 1 and 3 h after eating a weighed meal of their respective diets. In a subset of mice, energy expenditure was measured by indirect calorimetry during the first week of dietary intervention. Observed exclusively during the first week of intervention, whey significantly reduced body length (P<.01) and weight gain (P<.001) correlating positively with plasma concentrations of insulin-like growth factor-1. The combination diet displayed intermediate results indicating an interactive effect. Urea production, urea cycle activity, food intake and energy expenditure were unaffected by protein source. In conclusion, whey decreased growth-related parameters exclusively during the first week of dietary intervention. The early effect of whey could not be explained by food intake, energy expenditure, urea production or urea cycle activity but was correlated with plasma levels of insulin-like growth factor-1. PMID:25315863

Tranberg, Britt; Madsen, Andreas N; Hansen, Axel K; Hellgren, Lars I

2015-01-01

292

High-Gain Thompson-Scattering X-Ray Free-Electron Laser by Time-Synchronic Laterally Tilted Optical Wave  

NASA Astrophysics Data System (ADS)

A novel approach to generating coherent x rays with 109-1010 photons and femtoseconds duration per laser pulse is proposed. This high intensity x-ray source is realized first by the pulse front tilt of a lateral fed laser to extend the electron-laser synchronic interaction time by several orders, which accomplishes the high-gain free-electron-laser-type exponential growth process and coherent emission with highly microbunched electron beam. Second, two methods are presented to enhance the effective optical undulator strength parameter. One is to invoke lenses to focus two counterpropagating lasers that are at normal incidence to the electron beam as a transverse standing wave; the other is to invent a periodic microstructure that can significantly enhance the center electromagnetic field realized by a resonant standing wave and the quadrupole waveguides. The energy coupling efficiency between the electron beam and laser is therefore greatly improved to generate the high brightness x rays, which is demonstrated by analytical and simulation results.

Chang, Chao; Tang, Chuanxiang; Wu, Juhao

2013-02-01

293

Simultaneous optical recording of evoked and spontaneous transients of membrane potential and intracellular calcium concentration with high spatio-temporal resolution.  

PubMed

We have developed a system for simultaneous optical recording of transients of membrane potential and intracellular calcium concentration from mammalian brain slice preparations with high spatio-temporal resolution. Simultaneous recording was achieved by using two dedicated photodetectors together with two fluorescent indicators. Specifically, the calcium-sensitive dye Calcium Orange and the voltage-sensitive dye RH-414 were selected because they have overlapping excitation spectra, but separable emission spectra. Transverse guinea pig hippocampal slices were double-loaded by bath application of the membrane-permeant form of Calcium Orange and RH-414. Transients of intracellular calcium concentration and membrane potential associated with evoked neural activity in hippocampal areas CA1 and CA3 were recorded. Furthermore, we have recorded calcium and voltage transients associated with spontaneous epileptiform activity induced by bath application of an epileptogenic drug, 4-aminopyridine. The use of photodiode matrices (10 x 10 elements each) as detectors gives the high spatial (200 x 200 microns/element with a 10 x objective) and temporal resolution (570 microseconds/frame). The recording system also includes a CCD camera for obtaining images of the preparation and overlaying the image with the optically detected signals. A software package has been developed for setting up the experimental protocol(s) and for collecting, processing, displaying, and analyzing the data in an user-friendly, windows-based environment. PMID:8544487

Sinha, S R; Patel, S S; Saggau, P

1995-08-01

294

Self-assembly, highly modified spontaneous emission and energy transfer properties of LaPO4:Ce3+, Tb3+ inverse opals.  

PubMed

The modification of photonic crystals (PCs) on photoluminescence of rare earth (RE) ions has attracted considerable interest, however, the modification of PCs on energy transfer (ET) processes of two separate RE centers has not been investigated yet. In this paper, three-dimensional Ce(3+), Tb(3+)-codoped LaPO4 inverse opal PCs (IOPCs) were fabricated by the PMMA colloidal template method. The modification of the photonic stop band (PSB) on emission spectra and the dynamics of the 5d-4f transition of Ce(3+) and the 4f-4f transition of Tb(3+) ions were systematically studied. It is interesting to observe that the spontaneous decay rates (SDR) of (5)D4-(7)F5 in the IOPCs were suppressed as highly as 173% in contrast to the reference ground powder samples (REF) due to the modification of the effective refractive index (n(eff)). The energy transfer (ET) rate of Ce(3+) to Tb(3+) did not change in the IOPCs, however, the energy migration rate among Tb(3+) ions was largely restrained. It is also significant to observe that, in the IOPCs, the temperature quenching and radiation trapping of photoluminescence were greatly suppressed due to the periodic empty cavity structure of IOPCs, which is significant for high-power light sources and laser devices. PMID:23571776

Zhu, Yongsheng; Sun, Zhipeng; Yin, Ze; Song, Hongwei; Xu, Wen; Wang, Yunfeng; Zhang, Ligong; Zhang, Hanzhuang

2013-06-14

295

Spontaneous ovarian hyperstimulation syndrome.  

PubMed

Spontaneous forms of the ovarian hyperstimulation syndrome (sOHSS) are nearly always reported between 8 and 14 weeks of pregnancy and also with follicle-stimulating hormone (FSH) producing pituitary adenoma. The syndrome has been previously reported in rare instances of increased production of human chorionic gonadotrophin (hCG) such as multiple pregnancies, hydatiforme mole, polycystic ovary disease and elevated concentrations of thyroid-stimulating hormone (TSH) in hypothyreoidism. High levels of these hormones are able to stimulate by natural promiscuous activation the wild-type FSHr, resulting in sporadic presentations of the syndrome. Since 2003, only six different activating FSHr gene mutations have been reported in cases of familial or habitual sOHSS. In addition to five mutations which have been found in the transmembrane helices (Asp567Asn, Asp567Gly, Thr449Ile, Thr449Ala, Ile545Thr), the first germline mutation (c.383C > A, p. Ser 128 Tyr) in the extracelullar domain was identified. All five mutants were abnormally activated by TSH and normal levels of hCG while displaying constitutive activity. In contrast to these mutations, the p.Ser128Tyr mutant displayed an increase in sensitivity only toward hCG. Accordingly, the mutated FSHrs, may be hyperstimulated by the pregnancy-derived hCG or TSH, inducing the occurrence of the syndrome. In the differential diagnosis, malignancy, pregnancy luteoma and hyperreactio luteinalis would have to be excluded. In almost all of the cases the disease regresses spontaneously and could be managed expectantly or conservatively, but with termination of pregnancy or surgery in cases of complications. PMID:23941020

Kasum, Miro; Oreskovi?, Slavko; Jezek, Davor

2013-06-01

296

Effects of a High-Fat Diet on Spontaneous Metastasis of Lewis Lung Carcinoma in Plasminogen Activator Inhibitor-1 Deficient and Wild-Type Mice  

PubMed Central

This study investigated the effects of a high-fat diet on spontaneous metastasis of Lewis lung carcinoma (LLC) in plasminogen activator inhibitor-1 deficient (PAI-1?/?) and wild-type mice. The high-fat diet increased the number of pulmonary metastases by 60% (p<0.01), tumor cross-sectional area by 82% (p<0.05) and tumor volume by 130% (p<0.05) compared to the AIN93G diet. Deficiency in PAI-1 reduced the number of metastases by 35% (p<0.01) compared to wild-type mice. In mice fed the high-fat diet, PAI-1 deficiency reduced tumor cross-sectional area by 52% (p<0.05) and tumor volume by 61% (p<0.05) compared to their wild-type counterparts; however, PAI-1 deficiency affected neither area nor volume in mice fed the AIN93G diet. Adipose and plasma concentrations of PAI-1 were significantly higher in high-fat fed wild-type mice than in their AIN93G-fed counterparts. Adipose and plasma PAI-1 were not detectable in PAI-1?/? mice regardless of the diet. Mice deficient in PAI-1 showed significantly greater plasma concentrations of monocyte chemotactic protein-1, tumor necrosis factor-?, leptin, vascular endothelial growth factor, tissue inhibitor of metalloproteinase-1 and insulin compared to wild-type mice, indicating a compensatory overproduction of inflammatory cytokines, angiogenic factors and insulin in the absence of PAI-1. We conclude that PAI-1 produced by the host, including that by adipose tissue, promotes high-fat enhanced metastasis of LLC. PMID:25356654

Yan, Lin; DeMars, Lana C.

2014-01-01

297

High Basal Activity of the PTPN22 Gain-of-Function Variant Blunts Leukocyte Responsiveness Negatively Affecting IL10 Production in ANCA Vasculitis  

Microsoft Academic Search

Consequences of expression of the protein tyrosine phosphatase nonreceptor 22 (PTPN22) gain-of-function variant were evaluated in leukocytes from patients with anti-neutrophil cytoplasmic autoantibody (ANCA) disease. The frequency of the gain-of-function allele within the Caucasian patient cohort was 22% (OR 1.45), compared to general American Caucasian population (16.5%, p = 0.03). Examination of the basal phosphatase activity of PTPN22 gain-of-function protein

Yali Cao; Jiajin Yang; Kerry Colby; Susan L. Hogan; Yichun Hu; Caroline E. Jennette; Elisabeth A. Berg; Youkang Zhang; J. Charles Jennette; Ronald J. Falk; Gloria A. Preston

2012-01-01

298

High peak- and average-power pulse shaped fiber laser in the ns-regime applying step-index XLMA gain fibers  

NASA Astrophysics Data System (ADS)

Pulsed fiber lasers and continuous-wave (cw) fiber lasers have become the tool of choice in more and more laser based industrial applications like metal cutting and welding mainly because of their robustness, compactness, high brightness, high efficiency and reasonable costs. However, to further increase the productivity with those laser types there is a great demand for even higher laser power specifications. In this context we demonstrate a pulsed high peak- and averagepower fiber laser in a Master Oscillator Power Amplifier (MOPA) configuration with selectable pulse durations between 1 ns and several hundred nanoseconds. To overcome fiber nonlinearities such as stimulated Raman scattering (SRS) and self-phase-modulation (SPM) flexible Ytterbium doped extra-large mode area (XLMA) step index fibers, prepared by novel powder-sinter technology, have been used as gain fibers. As an example, for 12 ns pulses with a repetition rate of 10 kHz, a pump power limited average laser output power of more than 400 W in combination with peak powers of more than 3.5 MW (close to self-focusing-threshold) has been achieved in stable operation. The potentials of this laser system have been further explored towards longer pulse durations in order to achieve even higher pulse energies by means of pulse shaping techniques. In addition, investigations have been conducted with reduced pulse energies and repetition rates up to 500 kHz and average powers of more than 500 W at nearly diffraction limited beam quality.

Dinger, R.; Grundmann, F.-P.; Hapke, C.; Ruppik, S.

2014-03-01

299

Adaptive allocation of attentional gain  

PubMed Central

Humans are adept at distinguishing between stimuli that are very similar, an ability that is particularly crucial when the outcome is of serious consequence (e.g. for a surgeon or air traffic controller). Traditionally, selective attention was thought to facilitate perception by increasing the gain of sensory neurons tuned to the defining features of a behaviorally relevant object (e.g. color, orientation, etc.). In contrast, recent mathematical models counter-intuitively suggest that in many cases attentional gain should be applied to neurons that are tuned away from relevant features, especially when discriminating highly similar stimuli. Here we used psychophysical methods to critically evaluate these ‘ideal observer’ models. The data demonstrate that attention enhances the gain of the most informative sensory neurons, even when these neurons are tuned away from the behaviorally relevant target feature. Moreover, the degree to which an individual adopted optimal attentional gain settings by the end of testing predicted success rates on a difficult visual discrimination task, as well as the amount of task improvement that occurred across repeated testing sessions (learning). Contrary to most traditional accounts, these observations suggest that the primary function of attentional gain is not simply to enhance the representation of target features, but to optimize performance on the current perceptual task. Additionally, individual differences in gain suggest that the operating characteristics of low-level attentional phenomena are not stable trait-like attributes and that variability in how attention is deployed may play an important role in determining perceptual abilities. PMID:19776279

Scolari, Miranda; Serences, John T.

2009-01-01

300

Microarray comparative genomic hybridization reveals genome-wide patterns of DNA gains and losses in post-Chernobyl thyroid cancer.  

PubMed

Genetic gains and losses resulting from DNA strand breakage by ionizing radiation have been demonstrated in vitro and suspected in radiation-associated thyroid cancer. We hypothesized that copy number deviations might be more prevalent, and/or occur in genomic patterns, in tumors associated with presumptive DNA strand breakage from radiation exposure than in their spontaneous counterparts. We used cDNA microarray-based comparative genome hybridization to obtain genome-wide, high-resolution copy number profiles at 14,573 genomic loci in 23 post-Chernobyl and 20 spontaneous thyroid cancers. The prevalence of DNA gains in tumors from cases in exposed individuals was two- to fourfold higher than for cases in unexposed individuals and up to 10-fold higher for the subset of recurrent gains. DNA losses for all cases were low and more prevalent in spontaneous cases. We identified unique patterns of copy variation (mostly gains) that depended on a history of radiation exposure. Exposed cases, especially the young, harbored more recurrent gains that covered more of the genome. The largest regions, spanning 1.2 to 4.9 Mbp, were located at 1p36.32-.33, 2p23.2-.3, 3p21.1-.31, 6p22.1-.2, 7q36.1, 8q24.3, 9q34.11, 9q34.3, 11p15.5, 11q13.2-12.3, 14q32.33, 16p13.3, 16p11.2, 16q21-q12.2, 17q25.1, 19p13.31-qter, 22q11.21 and 22q13.2. Copy number changes, particularly gains, in post-Chernobyl thyroid cancer are influenced by radiation exposure and age at exposure, in addition to the neoplastic process. PMID:16953671

Kimmel, Robert R; Zhao, Lue Ping; Nguyen, Doan; Lee, Somnit; Aronszajn, Mark; Cheng, Chun; Troshin, Vladislav P; Abrosimov, Alexander; Delrow, Jeffrey; Tuttle, R Michael; Tsyb, Anatoli F; Kopecky, Kenneth J; Davis, Scott; Neiman, Paul E

2006-09-01

301

Spontaneous emission of a two-level static atom coupling with the electromagnetic vacuum fluctuations outside a high-dimensional Einstein Gauss-Bonnet black hole  

E-print Network

In present paper, by using the generalized DDC formalism, we investigate the spontaneous excitation of an static atom interacting with electromagnetic vacuum fluctuations outside a EGB black hole in $d$-dimensions. We find that spontaneous excitation does not occur in Boulware vacuum. The Gauss-Bonnet term has no effect on the stability of the atom. Finally, we discuss the contribution of the coupling constant and dimensional factor to the results in three different kinds of spacetime.

Ming Zhang; Zhan-Ying Yang; Rui-Hong Yue

2014-07-04

302

Optimal Weight Gain  

Microsoft Academic Search

Optimal birth weight and outcome are influenced by maternal weight gain. Low gestational weight gain is associated with poor\\u000a fetal growth and risk of preterm delivery. Excessive weight gain affects infant growth, body fatness in childhood, and the\\u000a potential for postpartum weight retention and future obesity. Guidelines from the Institute of Medicine recommend that a woman\\u000a with a normal body

Grace A. Falciglia; Kristin H. Coppage

303

Fucoxanthin-rich seaweed extract suppresses body weight gain and improves lipid metabolism in high-fat-fed C57BL/6J mice.  

PubMed

An ethanol extract of fucoxanthin-rich seaweed was examined for its effectiveness as a nutraceutical for body fat-lowering agent and for an antiobese effect based on mode of actions in C57BL/6J mice. Animals were randomized to receive a semi-purified high-fat diet (20% dietary fat, 10% corn oil and 10% lard) supplemented with 0.2% conjugated linoleic acid (CLA) as the positive control, 1.43% or 5.72% fucoxanthin-rich seaweed ethanol extract (Fx-SEE), equivalent to 0.05% or 0.2% dietary fucoxanthin for six weeks. Results showed that supplementation with both doses of Fx-SEE significantly reduced body and abdominal white adipose tissue (WAT) weights, plasma and hepatic triglyceride (TG), and/or cholesterol concentrations compared to the high-fat control group. Activities of adipocytic fatty acid (FA) synthesis, hepatic FA and TG synthesis, and cholesterol-regulating enzyme were also lowered by Fx-SEE supplement. Concentrations of plasma high-density lipoprotein-cholesterol, fecal TG and cholesterol, as well as FA oxidation enzyme activity and UCP1 mRNA expression in epididymal WAT were significantly higher in the Fx-SEE groups than in the high-fat control group. CLA treatment reduced the body weight gain and plasma TG concentration. Overall, these results indicate that Fx-SEE affects the plasma and hepatic lipid profile, fecal lipids and body fat mass, and alters hepatic cholesterol metabolism, FA synthesis and lipid absorption. PMID:20845386

Jeon, Seon-Min; Kim, Hye-Jin; Woo, Myoung-Nam; Lee, Mi-Kyung; Shin, Young Chul; Park, Yong Bok; Choi, Myung-Sook

2010-09-01

304

High-resolution molecular validation of self-renewal and spontaneous differentiation in clinical-grade adipose-tissue derived human mesenchymal stem cells.  

PubMed

Improving the effectiveness of adipose-tissue derived human mesenchymal stromal/stem cells (AMSCs) for skeletal therapies requires a detailed characterization of mechanisms supporting cell proliferation and multi-potency. We investigated the molecular phenotype of AMSCs that were either actively proliferating in platelet lysate or in a basal non-proliferative state. Flow cytometry combined with high-throughput RNA sequencing (RNASeq) and RT-qPCR analyses validate that AMSCs express classic mesenchymal cell surface markers (e.g., CD44, CD73/NT5E, CD90/THY1, and CD105/ENG). Expression of CD90 is selectively elevated at confluence. Self-renewing AMSCs express a standard cell cycle program that successively mediates DNA replication, chromatin packaging, cyto-architectural enlargement, and mitotic division. Confluent AMSCs preferentially express genes involved in extracellular matrix (ECM) formation and cellular communication. For example, cell cycle-related biomarkers (e.g., cyclins E2 and B2, transcription factor E2F1) and histone-related genes (e.g., H4, HINFP, NPAT) are elevated in proliferating AMSCs, while ECM genes are strongly upregulated (>10-fold) in quiescent AMSCs. AMSCs also express pluripotency genes (e.g., POU5F1, NANOG, KLF4) and early mesenchymal markers (e.g., NES, ACTA2) consistent with their multipotent phenotype. Strikingly, AMSCs modulate expression of WNT signaling components and switch production of WNT ligands (from WNT5A/WNT5B/WNT7B to WNT2/WNT2B), while upregulating WNT-related genes (WISP2, SFRP2, and SFRP4). Furthermore, post-proliferative AMSCs spontaneously express fibroblastic, osteogenic, chondrogenic, and adipogenic biomarkers when maintained in confluent cultures. Our findings validate the biological properties of self-renewing and multi-potent AMSCs by providing high-resolution quality control data that support their clinical versatility. PMID:24905804

Dudakovic, Amel; Camilleri, Emily; Riester, Scott M; Lewallen, Eric A; Kvasha, Sergiy; Chen, Xiaoyue; Radel, Darcie J; Anderson, Jarett M; Nair, Asha A; Evans, Jared M; Krych, Aaron J; Smith, Jay; Deyle, David R; Stein, Janet L; Stein, Gary S; Im, Hee-Jeong; Cool, Simon M; Westendorf, Jennifer J; Kakar, Sanjeev; Dietz, Allan B; van Wijnen, Andre J

2014-10-01

305

Effects of Acidic Polysaccharides from Gastrodia Rhizome on Systolic Blood Pressure and Serum Lipid Concentrations in Spontaneously Hypertensive Rats Fed a High-Fat Diet  

PubMed Central

The effects of acidic polysaccharides purified from Gastrodia rhizome on blood pressure and serum lipid levels in spontaneously hypertensive rats (SHR) fed a high-fat diet were investigated. Acidic polysaccharides were purified from crude polysaccharides by DEAE-Sepharose CL-6B. Thirty-six male SHR were randomly divided into three groups: Gastrodia rhizome crude polysaccharide (A), acidic polysaccharide (B) groups, and a control group (C). A 5-week oral administration of all treatment groups was performed daily in 3- to 8-week-old SHRs with a dose of 6 mg/kg of body weight/day. After 5 weeks of treatment, total cholesterol in the acidic polysaccharide group, at 69.7 ± 10.6 mg/dL, was lower than in the crude polysaccharide group (75.0 ± 6.0 mg/dL) and the control group (89.2 ± 7.4 mg/dL). In addition, triglyceride and low-density lipoprotein cholesterol levels in the acidic polysaccharide group were lower than in the crude polysaccharide and control groups. The atherogenic index of the acidic polysaccharide group was 46.3% lower than in the control group. Initial blood pressure after the initial three weeks on the high-fat diet averaged 195.9 ± 3.3 mmHg among all rats. Compared with the initial blood pressure, the final blood pressure in the control group was increased by 22.8 mmHg, whereas it decreased in the acidic polysaccharide group by 14.9 mmHg. These results indicate that acidic polysaccharides from Gastrodia rhizome reduce hypertension and improve serum lipid levels. PMID:22312280

Lee, Ok-Hwan; Kim, Kyung-Im; Han, Chan-Kyu; Kim, Young-Chan; Hong, Hee-Do

2012-01-01

306

Underrepresented Minority High School and College Students Report STEM-Pipeline Sustaining Gains After Participating in the Loma Linda University Summer Health Disparities Research Program  

PubMed Central

An urgent need exists for graduate and professional schools to establish evidence-based STEM (science, technology, engineering, and math) pipeline programs to increase the diversity of the biomedical workforce. An untapped yet promising pool of willing participants are capable high school students that have a strong STEM interest but may lack the skills and the guided mentoring needed to succeed in competitive STEM fields. This study evaluates and compares the impact of the Loma Linda University (LLU) Summer Health Disparities Research Program on high school (HS) and undergraduate (UG) student participants. The primary focus of our summer research experience (SRE) is to enhance the research self-efficacy of the participants by actively involving them in a research project and by providing the students with personalized mentoring and targeted career development activities, including education on health disparities. The results of our study show that our SRE influenced terminal degree intent and increased participant willingness to incorporate research into future careers for both the HS and the UG groups. The quantitative data shows that both the HS and the UG participants reported large, statistically significant gains in self-assessed research skills and research self-efficacy. Both participant groups identified the hands-on research and the mentor experience as the most valuable aspects of our SRE and reported increased science skills, increased confidence in science ability and increased motivation and affirmation to pursue a science career. The follow-up data indicates that 67% of the HS participants and 90% of the UG participants graduated from college with a STEM degree; for those who enrolled in graduate education, 61% and 43% enrolled in LLU, respectively. We conclude that structured SREs can be highly effective STEM strengthening interventions for both UG and HS students and may be a way to measurably increase institutional and biomedical workforce diversity. PMID:25250695

Salto, Lorena M.; Riggs, Matt L.; Delgado De Leon, Daisy; Casiano, Carlos A.; De Leon, Marino

2014-01-01

307

Underrepresented minority high school and college students report STEM-pipeline sustaining gains after participating in the Loma Linda University Summer Health Disparities Research Program.  

PubMed

An urgent need exists for graduate and professional schools to establish evidence-based STEM (science, technology, engineering, and math) pipeline programs to increase the diversity of the biomedical workforce. An untapped yet promising pool of willing participants are capable high school students that have a strong STEM interest but may lack the skills and the guided mentoring needed to succeed in competitive STEM fields. This study evaluates and compares the impact of the Loma Linda University (LLU) Summer Health Disparities Research Program on high school (HS) and undergraduate (UG) student participants. The primary focus of our summer research experience (SRE) is to enhance the research self-efficacy of the participants by actively involving them in a research project and by providing the students with personalized mentoring and targeted career development activities, including education on health disparities. The results of our study show that our SRE influenced terminal degree intent and increased participant willingness to incorporate research into future careers for both the HS and the UG groups. The quantitative data shows that both the HS and the UG participants reported large, statistically significant gains in self-assessed research skills and research self-efficacy. Both participant groups identified the hands-on research and the mentor experience as the most valuable aspects of our SRE and reported increased science skills, increased confidence in science ability and increased motivation and affirmation to pursue a science career. The follow-up data indicates that 67% of the HS participants and 90% of the UG participants graduated from college with a STEM degree; for those who enrolled in graduate education, 61% and 43% enrolled in LLU, respectively. We conclude that structured SREs can be highly effective STEM strengthening interventions for both UG and HS students and may be a way to measurably increase institutional and biomedical workforce diversity. PMID:25250695

Salto, Lorena M; Riggs, Matt L; Delgado De Leon, Daisy; Casiano, Carlos A; De Leon, Marino

2014-01-01

308

Nutrition During Weight Gain  

E-print Network

, Department of Food Science and Human Nutrition, 3/09 MSU is an affirmative-action, equal-opportunity employerNutrition During Pregnancy Weight Gain: The right weight gain (not too little and not too much you are taking, such as vitamins, minerals or herbs. Nutrition during pregnancy is very important

309

Spontaneous combustion of hydrogen  

NASA Technical Reports Server (NTRS)

It is shown by the author's experiments that hydrogen which escapes to the atmosphere through openings in the system may burn spontaneously if it contains dust. Purely thermal reasoning can not account for the combustion. It seems to be rather an electrical ignition. In order to determine whether the cause of the spontaneous ignition was thermo-chemical, thermo-mechanical, or thermo-electrical, the experiments in this paper were performed.

Nusselt, Wilhelm; Pothmann, PH

1923-01-01

310

Comparing gains and losses.  

PubMed

Loss aversion in choice is commonly assumed to arise from the anticipation that losses have a greater effect on feelings than gains, but evidence for this assumption in research on judged feelings is mixed. We argue that loss aversion is present in judged feelings when people compare gains and losses and assess them on a common scale. But many situations in which people judge and express their feelings lack these features. When judging their feelings about an outcome, people naturally consider a context of similar outcomes for comparison (e.g., they consider losses against other losses). This process permits gains and losses to be normed separately and produces psychological scale units that may not be the same in size or meaning for gains and losses. Our experiments show loss aversion in judged feelings for tasks that encourage gain-loss comparisons, but not tasks that discourage them, particularly those using bipolar scales. PMID:20739673

McGraw, A Peter; Larsen, Jeff T; Kahneman, Daniel; Schkade, David

2010-10-01

311

Rice koji reduced body weight gain, fat accumulation, and blood glucose level in high-fat diet-induced obese mice.  

PubMed

Rice koji is considered a readily accessible functional food that may have health-promoting effects. We investigated whether white, yellow, and red koji have the anti-obesity effect in C57BL/6J mice fed a high-fat diet (HFD), which is a model for obesity. Mice were fed HFD containing 10% (w/w) of rice koji powder or steamed rice for 4 weeks. Weight gain, epididymal white adipose tissue, and total adipose tissue weight were significantly lower in all rice koji groups than in the HFD-rice group after 4 weeks. Feed efficiency was significantly reduced in the yellow koji group. Blood glucose levels were significantly lower in the white and red koji groups with HOMA-R and leptin levels being reduced in the white koji group. White and red koji increased glucose uptake and GLUT4 protein expression in L6 myotube cells. These results showed that all rice koji have the anti-obesity or anti-diabetes effects although the mechanisms may differ depending on the type of rice koji consumed. PMID:25237599

Yoshizaki, Yumiko; Kawasaki, Chihiro; Cheng, Kai-Chun; Ushikai, Miharu; Amitani, Haruka; Asakawa, Akihiro; Okutsu, Kayu; Sameshima, Yoshihiro; Takamine, Kazunori; Inui, Akio

2014-01-01

312

Rice koji reduced body weight gain, fat accumulation, and blood glucose level in high-fat diet-induced obese mice  

PubMed Central

Rice koji is considered a readily accessible functional food that may have health-promoting effects. We investigated whether white, yellow, and red koji have the anti-obesity effect in C57BL/6J mice fed a high-fat diet (HFD), which is a model for obesity. Mice were fed HFD containing 10% (w/w) of rice koji powder or steamed rice for 4 weeks. Weight gain, epididymal white adipose tissue, and total adipose tissue weight were significantly lower in all rice koji groups than in the HFD-rice group after 4 weeks. Feed efficiency was significantly reduced in the yellow koji group. Blood glucose levels were significantly lower in the white and red koji groups with HOMA-R and leptin levels being reduced in the white koji group. White and red koji increased glucose uptake and GLUT4 protein expression in L6 myotube cells. These results showed that all rice koji have the anti-obesity or anti-diabetes effects although the mechanisms may differ depending on the type of rice koji consumed. PMID:25237599

Yoshizaki, Yumiko; Kawasaki, Chihiro; Cheng, Kai-Chun; Ushikai, Miharu; Amitani, Haruka; Asakawa, Akihiro; Okutsu, Kayu; Sameshima, Yoshihiro; Takamine, Kazunori

2014-01-01

313

High-Throughput Analysis of NF-?B Dynamics in Single Cells Reveals Basal Nuclear Localization of NF-?B and Spontaneous Activation of Oscillations  

PubMed Central

NF-?B is a transcription factor that upon activation undergoes cycles of cytoplasmic-to-nuclear and nuclear-to-cytoplasmic transport, giving rise to so called “oscillations”. In turn, oscillations tune the transcriptional output. Since a detailed understanding of oscillations requires a systems biology approach, we developed a method to acquire and analyze large volumes of data on NF-?B dynamics in single cells. We measured the time evolution of the nuclear to total ratio of GFP-p65 in knock-in mouse embryonic fibroblasts using time-lapse imaging. We automatically produced a precise segmentation of nucleus and cytoplasm based on an accurate estimation of the signal and image background. Finally, we defined a set of quantifiers that describe the oscillatory dynamics, which are internally normalized and can be used to compare data recorded by different labs. Using our method, we analyzed NF-?B dynamics in over 2000 cells exposed to different concentrations of TNF- ? ?. We reproduced known features of the NF-?B system, such as the heterogeneity of the response in the cell population upon stimulation and we confirmed that a fraction of the responding cells does not oscillate. We also unveiled important features: the second and third oscillatory peaks were often comparable to the first one, a basal amount of nuclear NF-?B could be detected in unstimulated cells, and at any time a small fraction of unstimulated cells showed spontaneous random activation of the NF-?B system. Our work lays the ground for systematic, high-throughput, and unbiased analysis of the dynamics of transcription factors that can shuttle between the nucleus and other cell compartments. PMID:24595030

Zambrano, Samuel; Bianchi, Marco E.; Agresti, Alessandra

2014-01-01

314

High average power scaleable thin-disk laser  

DOEpatents

Using a thin disk laser gain element with an undoped cap layer enables the scaling of lasers to extremely high average output power values. Ordinarily, the power scaling of such thin disk lasers is limited by the deleterious effects of amplified spontaneous emission. By using an undoped cap layer diffusion bonded to the thin disk, the onset of amplified spontaneous emission does not occur as readily as if no cap layer is used, and much larger transverse thin disks can be effectively used as laser gain elements. This invention can be used as a high average power laser for material processing applications as well as for weapon and air defense applications.

Beach, Raymond J. (Livermore, CA); Honea, Eric C. (Sunol, CA); Bibeau, Camille (Dublin, CA); Payne, Stephen A. (Castro Valley, CA); Powell, Howard (Livermore, CA); Krupke, William F. (Pleasanton, CA); Sutton, Steven B. (Manteca, CA)

2002-01-01

315

Limited Relationship between Cervico-Vaginal Fluid Cytokine Profiles and Cervical Shortening in Women at High Risk of Spontaneous Preterm Birth  

PubMed Central

Objective To determine the relationship between high vaginal pro-inflammatory cytokines and cervical shortening in women at high risk of spontaneous preterm labor and to assess the influence of cervical cerclage and vaginal progesterone on this relationship. Methods This prospective longitudinal observational study assessed 112 women with at least one previous preterm delivery between 16 and 34 weeks’ gestation. Transvaginal cervical length was measured and cervico-vaginal fluid sampled every two weeks until 28 weeks. If the cervix shortened (<25 mm) before 24 weeks’ gestation, women (cases) were randomly assigned to cerclage or progesterone and sampled weekly. Cytokine concentrations were measured in a subset of cervico-vaginal fluid samples (n?=?477 from 78 women) by 11-plex fluid-phase immunoassay. Results All 11 inflammatory cytokines investigated were detected in cervico-vaginal fluid from women at high risk of preterm birth, irrespective of later cervical shortening. At less than 24 weeks’ gestation and prior to intervention, women destined to develop a short cervix (n?=?36) exhibited higher cervico-vaginal concentrations than controls (n?=?42) of granulocyte-macrophage colony-stimulating factor [(GM-CSF) 16.2 fold increase, confidence interval (CI) 1.8–147; p?=?0.01] and monocyte chemotactic protein-1 [(MCP-1) 4.8, CI 1.0–23.0; p?=?0.05]. Other cytokines were similar between cases and controls. Progesterone treatment did not suppress cytokine concentrations. Interleukin (IL)-6, IL-8, granulocyte colony-stimulating factor (G-CSF), interferon (IFN)-? and tumour necrosis factor (TNF)-? concentrations were higher following randomization to cerclage versus progesterone (p<0.05). Cerclage, but not progesterone treatment, was followed by a significant increase in cervical length [mean 11.4 mm, CI 5.0–17.7; p<0.001]. Conclusions Although GM-CSF and MCP-1 cervico-vaginal fluid concentrations were raised, the majority of cervico-vaginal cytokines did not increase in association with cervical shortening. Progesterone treatment showed no significant anti-inflammation action on cytokine concentrations. Cerclage insertion was associated with an increase in the majority of inflammatory markers and cervical length. PMID:23300664

Chandiramani, Manju; Seed, Paul T.; Orsi, Nicolas M.; Ekbote, Uma V.; Bennett, Phillip R.; Shennan, Andrew H.; Tribe, Rachel M.

2012-01-01

316

Amplified spontaneous emission and lasing properties of bisfluorene-cored dendrimers  

NASA Astrophysics Data System (ADS)

A study of the amplified spontaneous emission (ASE) properties of three bisfluorene-cored dendrimers in the solid state is reported. The results show that the dendron type has a strong impact on the photoluminescence quantum yield and affects the ASE threshold, the optical gain, and loss coefficients. Optically pumped distributed feedback lasers operating in the blue spectral region were fabricated by spin coating the dendrimer films on top of a two-dimensional corrugated fused silica substrate. A best lasing threshold of 4.5?J/cm2 and a slope efficiency of 8.3% were obtained, which demonstrate the high potential of these materials for laser applications.

Ribierre, J. C.; Tsiminis, G.; Richardson, S.; Turnbull, G. A.; Samuel, I. D. W.; Barcena, H. S.; Burn, P. L.

2007-08-01

317

Scintillator high-gain avalanche rushing photoconductor active-matrix flat panel imager: Zero-spatial frequency x-ray imaging properties of the solid-state SHARP sensor structure  

PubMed Central

Purpose: The authors are investigating the feasibility of a new type of solid-state x-ray imaging sensor with programmable avalanche gain: scintillator high-gain avalanche rushing photoconductor active matrix flat panel imager (SHARP-AMFPI). The purpose of the present work is to investigate the inherent x-ray detection properties of SHARP and demonstrate its wide dynamic range through programmable gain. Methods: A distributed resistive layer (DRL) was developed to maintain stable avalanche gain operation in a solid-state HARP. The signal and noise properties of the HARP-DRL for optical photon detection were investigated as a function of avalanche gain both theoretically and experimentally, and the results were compared with HARP tube (with electron beam readout) used in previous investigations of zero spatial frequency performance of SHARP. For this new investigation, a solid-state SHARP x-ray image sensor was formed by direct optical coupling of the HARP-DRL with a structured cesium iodide (CsI) scintillator. The x-ray sensitivity of this sensor was measured as a function of avalanche gain and the results were compared with the sensitivity of HARP-DRL measured optically. The dynamic range of HARP-DRL with variable avalanche gain was investigated for the entire exposure range encountered in radiography/fluoroscopy (R/F) applications. Results: The signal from HARP-DRL as a function of electric field showed stable avalanche gain, and the noise associated with the avalanche process agrees well with theory and previous measurements from a HARP tube. This result indicates that when coupled with CsI for x-ray detection, the additional noise associated with avalanche gain in HARP-DRL is negligible. The x-ray sensitivity measurements using the SHARP sensor produced identical avalanche gain dependence on electric field as the optical measurements with HARP-DRL. Adjusting the avalanche multiplication gain in HARP-DRL enabled a very wide dynamic range which encompassed all clinically relevant medical x-ray exposures. Conclusions: This work demonstrates that the HARP-DRL sensor enables the practical implementation of a SHARP solid-state x-ray sensor capable of quantum noise limited operation throughout the entire range of clinically relevant x-ray exposures. This is an important step toward the realization of a SHARP-AMFPI x-ray flat-panel imager. PMID:23127101

Wronski, M.; Zhao, W.; Tanioka, K.; DeCrescenzo, G.; Rowlands, J. A.

2012-01-01

318

Brazilian Multicentre Study on Preterm Birth (EMIP): Prevalence and Factors Associated with Spontaneous Preterm Birth  

PubMed Central

Background Preterm birth rate is increasing and is currently a worldwide concern. The purpose of this study was to estimate the prevalence of preterm birth in a sample of health facilities in Brazil and to identify the main risk factors associated with spontaneous preterm births. Methods and Findings This was a multicentre cross sectional study on preterm births in 20 referral obstetric hospitals with a case-control component to identify factors associated with spontaneous preterm birth. Surveillance was implemented at all centres to identify preterm births. For eligible consenting women, data were collected through a post-delivery questionnaire completed with information from all mother-newborn medical records until death or discharge or at a maximum of 60 days post-delivery, whichever came first. The risk of spontaneous preterm birth was estimated with OR and 95%CI for several predictors. A non-conditional logistic regression analysis was then performed to identify independently associated factors. The overall prevalence of preterm birth was 12.3%. Among them, 64.6% were spontaneous and 35.4% therapeutic. In the case-control component, 2,682 spontaneous preterm births were compared to a sample of 1,146 term births. Multivariate analyses identified the following as risk factors for spontaneous preterm birth among women with at least one previous birth: a previous preterm birth (ORadj?=?3.19, 2.30–4.43), multiple pregnancy (ORadj?=?29.06, 8.43–100.2), cervical insufficiency (ORadj?=?2.93, 1.07–8.05), foetal malformation (ORadj?=?2.63, 1.43–4.85), polyhydramnios (ORadj?=?2.30, 1.17–4.54), vaginal bleeding (ORadj?=?2.16, 1.50–3.11), and previous abortion (ORadj?=?1.39, 1.08–1.78). High BMI (ORadj?=?0.94, 0.91–0.97) and weight gain during gestation (ORadj?=?0.92, 0.89–0.95) were found to be protective factors. Conclusions The preterm birth rate in these health facilities in Brazil is high and spontaneous preterm births account for two thirds of them. A better understanding of the factors associated with spontaneous preterm birth is of utmost importance for planning effective measures to reduce the burden of its increasing rates. PMID:25299699

Passini, Renato; Cecatti, Jose G.; Lajos, Giuliane J.; Tedesco, Ricardo P.; Nomura, Marcelo L.; Dias, Tabata Z.; Haddad, Samira M.; Rehder, Patricia M.; Pacagnella, Rodolfo C.; Costa, Maria L.; Sousa, Maria H.

2014-01-01

319

VECSEL gain characterization.  

PubMed

We present the first full gain characterization of two vertical external cavity surface emitting laser (VECSEL) gain chips with similar designs operating in the 960-nm wavelength regime. We optically pump the structures with continuous-wave (cw) 808-nm radiation and measure the nonlinear reflectivity for 130-fs and 1.4-ps probe pulses as function of probe pulse fluence, pump power, and heat sink temperature. With this technique we are able to measure the saturation behavior for VECSEL gain chips for the first time. The characterization with 1.4-ps pulses resulted in saturation fluences of 40-80 ?J/cm2, while probing with 130-fs pulses yields reduced saturation fluences of 30-50 ?J/cm2 for both structures. For both pulse durations this is lower than previously assumed. A small-signal gain of up to 5% is obtained with this technique. Furthermore, in a second measurement setup, we characterize the spectral dependence of the gain using a tunable cw probe beam. We measure a gain bandwidth of over 26 nm for both structures, full width at half maximum. PMID:22418171

Mangold, Mario; Wittwer, Valentin J; Sieber, Oliver D; Hoffmann, Martin; Krestnikov, Igor L; Livshits, Daniil A; Golling, Matthias; Südmeyer, Thomas; Keller, Ursula

2012-02-13

320

Biomodal spontaneous fission  

SciTech Connect

Investigations of mass and kinetic-energy distributions from spontaneous fission have been extended in recent years to an isotope of element 104 and, for half-lives, to an isotope of element 108. The results have been surprising in that spontaneous fission half-lives have turned out to be much longer than expected and mass and kinetic- energy distributions were found to abruptly shift away from those of the lighter actinides, showing two modes of fission. These new developments have caused a re-evaluation of our understanding of the fission process, bringing an even deeper appreciation of the role played by nuclear shell effects upon spontaneous fission properties. 16 refs., 10 figs.

Hulet, E.K. (Lawrence Livermore National Lab., CA (USA))

1989-09-26

321

Simplified ASE correction algorithm for variable gain-flattened erbium-doped fiber amplifier.  

PubMed

We demonstrate a simplified algorithm to manifest the contribution of amplified spontaneous emission in variable gain-flattened Erbium-doped fiber amplifier (EDFA). The detected signal power at the input and output ports of EDFA comprises of both signal and noise. The generated amplified spontaneous emission from EDFA cannot be differentiated by photodetector which leads to underestimation of the targeted gain value. This gain penalty must be taken into consideration in order to obtain the accurate gain level. By taking the average gain penalty within the dynamic gain range, the targeted output power is set higher than the desired level. Thus, the errors are significantly reduced to less than 0.15 dB from 15 dB to 30 dB desired gain values. PMID:19506658

Mahdi, Mohd Adzir; Sheih, Shou-Jong; Adikan, Faisal Rafiq Mahamd

2009-06-01

322

Microchannel plate modal gain variations with temperature  

NASA Technical Reports Server (NTRS)

Measurements of the modal gain of two high-gain curved-channel microchannel plates (MCPs) at various operating temperatures are presented. Both MCPs were fabricated from the Long Life glass with 12-micron diam channels on 15-micron centers. The modal gain was found to decrease with increasing temperature at a rate of -0.1 percent C. This reduction of gain with temperature is attributed primarily to an axial temperature gradient along each MCP channel creating a nonuniform electric field within the channel that lowers the effective output gain. A lowering of the secondary electron yield resulting from increased phonon scattering of secondary electrons released within the walls of the MCP channels was assessed, but was found to have a negligible contribution to the drop in gain with temperature.

Slater, David C.; Timothy, J. G.

1993-01-01

323

Spontaneous vesicle recycling in the synaptic bouton  

PubMed Central

The trigger for synaptic vesicle exocytosis is Ca2+, which enters the synaptic bouton following action potential stimulation. However, spontaneous release of neurotransmitter also occurs in the absence of stimulation in virtually all synaptic boutons. It has long been thought that this represents exocytosis driven by fluctuations in local Ca2+ levels. The vesicles responding to these fluctuations are thought to be the same ones that release upon stimulation, albeit potentially triggered by different Ca2+ sensors. This view has been challenged by several recent works, which have suggested that spontaneous release is driven by a separate pool of synaptic vesicles. Numerous articles appeared during the last few years in support of each of these hypotheses, and it has been challenging to bring them into accord. We speculate here on the origins of this controversy, and propose a solution that is related to developmental effects. Constitutive membrane traffic, needed for the biogenesis of vesicles and synapses, is responsible for high levels of spontaneous membrane fusion in young neurons, probably independent of Ca2+. The vesicles releasing spontaneously in such neurons are not related to other synaptic vesicle pools and may represent constitutively releasing vesicles (CRVs) rather than bona fide synaptic vesicles. In mature neurons, constitutive traffic is much dampened, and the few remaining spontaneous release events probably represent bona fide spontaneously releasing synaptic vesicles (SRSVs) responding to Ca2+ fluctuations, along with a handful of CRVs that participate in synaptic vesicle turnover. PMID:25538561

Truckenbrodt, Sven; Rizzoli, Silvio O.

2014-01-01

324

High-Gain Subnanowatt Power Consumption Hybrid Complementary Logic Inverter with WSe2 Nanosheet and ZnO Nanowire Transistors on Glass.  

PubMed

A 1D-2D hybrid complementary logic inverter comprising of ZnO nanowire and WSe2 nanosheet field-effect transistors (FETs) is fabricated on glass, which shows excellent static and dynamic electrical performances with a voltage gain of ?60, sub-nanowatt power consumption, and at least 1 kHz inverting speed. PMID:25377731

Shokouh, Seyed Hossein Hosseini; Pezeshki, Atiye; Ali Raza, Syed Raza; Lee, Hee Sung; Min, Sung-Wook; Jeon, Pyo Jin; Shin, Jae Min; Im, Seongil

2015-01-01

325

High-gain photorefractive two-beam coupling in semi-insulating GaAs with pump-controlled suppression of the Schottky barrier  

NASA Astrophysics Data System (ADS)

Suppression of the Schottky barrier effect in semi-insulating GaAs is demonstrated by centering the pump irradiation on the reverse bias crystal-electrode interface. A photorefractive gain coefficient ? of 2.7 cm-1 is achieved. The irradiation suppression overcomes the need for externally applied ohmic contacts.

Chomsky, Doron; Sternklar, Shmuel; Zigler, Arie; Jackel, Steven

1990-07-01

326

Spontaneous Emission of a Two-Level Static Atom Coupling with Electromagnetic Vacuum Fluctuations Outside a High-Dimensional Einstein Gauss–Bonnet Black Hole  

NASA Astrophysics Data System (ADS)

Using the generalized formalism of Dalibard, Dupont–Roc and Cohen–Tannoudji we investigate the spontaneous excitation of a static atom interacting with electromagnetic vacuum fluctuations outside an Einstein Gauss–Bonnet black hole in d-dimensions. It shows that spontaneous excitation does not occur in a Boulware vacuum, while exists in an Unruh vacuum and Hartle–Hawking vacuum. As to the total rate of change of the atomic energy, it does not receive the contribution from the coupling constant of the Gauss–Bonnet term at spatial infinity only the dimensional parameter has the contribution to it. Near the event horizon, both the coupling constant and the dimension p contribute to the total rate of change of the atomic energy in all three kinds of vacuum. We discuss the contribution of the coupling constant and dimensional factor to the results in three different kinds of spacetime lastly.

Zhang, Ming; Yang, Zhan-Ying; Yue, Rui-Hong

2014-10-01

327

High levels of NK cells in the peripheral blood of patients affected with anti-phospholipid syndrome and recurrent spontaneous abortion: a potential new hypothesis  

Microsoft Academic Search

Objectives. No data regarding phenotypic assets of circulating lymphocytes in anti-phospholipid syndrome (APS) are reported in the literature. Role of anti-phospholipid antibodies (aPL) in recurrent spontaneous abortion (RSA) remains uncertain, while natural killer (NK)- cells are involved in RSA pathogenesis. In this study, patients affected with APS without RSA, APS with RSA and RSA without aPL were studied for NK-cell

C. Perricone; C. De Carolis; R. Giacomelli; G. Zaccari; P. Cipriani; E. Bizzi; R. Perricone

2007-01-01

328

Receiver Gain Modulation Circuit  

NASA Technical Reports Server (NTRS)

A receiver gain modulation circuit (RGMC) was developed that modulates the power gain of the output of a radiometer receiver with a test signal. As the radiometer receiver switches between calibration noise references, the test signal is mixed with the calibrated noise and thus produces an ensemble set of measurements from which ensemble statistical analysis can be used to extract statistical information about the test signal. The RGMC is an enabling technology of the ensemble detector. As a key component for achieving ensemble detection and analysis, the RGMC has broad aeronautical and space applications. The RGMC can be used to test and develop new calibration algorithms, for example, to detect gain anomalies, and/or correct for slow drifts that affect climate-quality measurements over an accelerated time scale. A generalized approach to analyzing radiometer system designs yields a mathematical treatment of noise reference measurements in calibration algorithms. By treating the measurements from the different noise references as ensemble samples of the receiver state, i.e. receiver gain, a quantitative description of the non-stationary properties of the underlying receiver fluctuations can be derived. Excellent agreement has been obtained between model calculations and radiometric measurements. The mathematical formulation is equivalent to modulating the gain of a stable receiver with an externally generated signal and is the basis for ensemble detection and analysis (EDA). The concept of generating ensemble data sets using an ensemble detector is similar to the ensemble data sets generated as part of ensemble empirical mode decomposition (EEMD) with exception of a key distinguishing factor. EEMD adds noise to the signal under study whereas EDA mixes the signal with calibrated noise. It is mixing with calibrated noise that permits the measurement of temporal-functional variability of uncertainty in the underlying process. The RGMC permits the evaluation of EDA by modulating the receiver gain using an external signal. Without the RGMC, samples of calibrated references from radiometers form an ensemble data set of the natural occurring fluctuations within a receiver. By driving the gain of an otherwise stable receiver with an external signal, the conceptual framework and generalization of the mathematics of EDA can be tested. A series of measurements was conducted to evaluate and characterize the performance of the RGMC. Test signals stepped the RGMC across its dynamic range of performance using a radiometer that sampled four noise references; analysis indicates that the RGMC successfully modulated the receiver gain with an external signal. Calibration algorithms applied to four noise references demonstrate the RGMC produced ensemble data sets of the external signal.

Jones, Hollis; Racette, Paul; Walker, David; Gu, Dazhen

2011-01-01

329

Perioperative spontaneous bilateral suprachoroidal hemorrhage  

PubMed Central

Summary Suprachoroidal hemorrhage is a rare condition, occurring most commonly in the perioperative period, although cases of unilateral spontaneous hemorrhages have been reported. We report a case of bilateral spontaneous suprachoroidal hemorrhage and discuss the potential causative factors. PMID:23362387

Haridas, Anjana; Litwin, Andre S.; Coker, Timothy

2011-01-01

330

Internal electric fields due to piezoelectric and spontaneous polarizations in CdZnO/MgZnO quantum well  

NASA Astrophysics Data System (ADS)

We have investigated optical properties as a function of internal and external fields in the quantum well (QW). Optical properties of CdZnO/MgZnO QW structures are investigated by using many-body effects. The CdZnO/MgZnO QW structure with high Cd composition is found to have smaller optical gain because the strain-induced piezoelectric polarization and the spontaneous polarization in the well increase with the inclusion of Cd. These results demonstrate that high performance laser diode operation can be realized in CdZnO/MgZnO QW structures by reducing those polarizations adopting dipole reverse method.

Jeon, H. C.; Lee, S. J.; Kang, T. W.; Park, S. H.; Yeo, Yung Kee; George, T. F.

2011-12-01

331

GaNWW-oxide metal base transistor with very large current gain and power gain  

E-print Network

GaNÃ?WÃ?W-oxide metal base transistor with very large current gain and power gain K. Mochizuki,a) K 2000 We demonstrate a GaN/W/W-oxide metal base transistor MBT whose collector is formed by oxidizing high due to the difficulty in achieving a high hole concentration and mobility. The metal base

Asbeck, Peter M.

332

1.55-micron multiquantum well semiconductor optical amplifier with low gain ripple and high coupling efficiency for photonic circuit integration  

Microsoft Academic Search

The Letter demonstrates a 1.55-micron multiquantum well amplifier on an extended InGaAsP passive waveguide with only +\\/- 0.14 dB gain. Reflectivity less than 8 x 10 exp -5 from active-to-passive transitions and 41 percent coupling efficiency from a single-mode fiber are obtained. These amplifiers are suitable for integration with other optical devices in photonic integrated circuits.

M. A. Newkirk; B. I. Miller; U. Koren; M. G. Young; M. Chien; R. M. Jopson; G. Raybon; C. A. Burrus; H. M. Presby

1993-01-01

333

A narrow-channel, 0.2-micron gate-length, double-quantum-well pseudomorphic MODFET with high power gain at millimeter-wave frequencies  

Microsoft Academic Search

State-of-the-art pseudomorphic MODFETs were developed with metallurgical gate lengths between 0.22 and 0.25 micron, very short source-to-drain spacings of 0.7 micron, and a double-quantum-well material structure. S-parameter measurements were performed on these 60-micron gate-width devices up to 40 GHz. From these S-parameter measurements, an extrapolated value of 82 GHz was estimated for Ft. Modeling of the power gain as a

George M. Metze; Timothy T. Lee; J. F. Bass; P. L. Laux; H. C. Carlson

1990-01-01

334

Roof Coating Procedures and Their Productivity Gains  

E-print Network

Roof Coating Procedures and their Productivity Gains John Bonaby and Dr. Diane Schaub, University of Florida As building envelope improvements are realized in organizations as ways to insulate businesses from high energy costs, the relative...

Bonaby, J.; Schaub, D.

2006-01-01

335

Gain and Phase-margin measurements  

NASA Technical Reports Server (NTRS)

Simple battery-powered test circuit will contribute negligible error when taking open-loop measurements of gain and phase parameters. This is especially helpful when measuring high-grain circuits containing integrators.

Pierce, B. D.

1977-01-01

336

Endothelin receptor A blockade reduces proteinuria and vascular hypertrophy in spontaneously hypertensive rats on high-salt diet in a blood-pressure-independent manner.  

PubMed

The renal endothelin (ET) system is involved in the pathogenesis of kidney fibrosis as well as blood pressure control by regulating tubular sodium excretion. Long-term effects of ETA receptor blockade on blood pressure and kidney function in spontaneously hypertensive rats (SHRs) on a high-salt diet are unknown. We treated SHRs on a 6% (w/v) NaCl sodium diet (SHR-S) for 48 weeks with the ETA antagonist LU 135252 (whose selectivity for ETA is 150 times greater than for ETB) with 10, 30 and 100 mg x kg(-1) x day(-1) or placebo. The ETA antagonist had at no time-point any effect on blood pressure. Glomerular filtration rate was normal in SHR-S and not altered by LU 135252. However, urinary albumin excretion was markedly reduced by the ETA antagonist (SHR-S, 145+/-50 mg/day; SHR-S+10 mg x kg(-1) x day(-1) LU 135252, 33+/-11 mg/day, P<0.05 versus SHR-S; SHR-S+30 mg x kg(-1) x day(-1) LU 135252, 55+/-16 mg/day and SHR-S+100 mg x kg(-1) x day(-1) LU 135252, 32+/-11 mg/day, P<0.05 versus SHR-S at both concentrations). Total urinary protein excretion was likewise significantly reduced by treatment with 10 mg.kg(-1).day(-1) LU 135252 (SHR-S, 0.25+/-0.06 g/day; SHR-S+10 mg x kg(-1) x day(-1) LU 135252, 0.089+/-0.01 g/day, P<0.05 versus SHR-S). The higher dosages of LU 135252 showed only a trend towards reduction of total urinary protein excretion. Computer-aided image analysis after haematoxylin/eosin and periodic acid-Schiff staining revealed that treatment with 10 mg x kg(-1) x day(-1) LU 135252 significantly reduces the media/lumen ratio of intrarenal arteries. Higher dosages of LU 135252 were less effective. Renal matrix protein synthesis in SHR-S was not altered by LU 135252. In conclusion, the renal ET system contributes in a blood-pressure-independent manner to the regulation of urinary protein excretion and renal vascular hypertrophy in SHR-S. Lower doses of the ETA antagonist were more effective, indicating that a potential additional blockade of the ETB receptor using higher doses of LU 135252 seems to oppose the beneficial effects of a sole ETA blockade. Urinary protein excretion is an independent risk factor of chronic renal failure, thus ETA antagonists might be a therapeutic tool to prevent proteinuria-induced chronic renal failure. PMID:12193128

Trenkner, Jörg; Priem, Friedrich; Bauer, Christian; Neumayer, Hans-Hellmut; Raschak, Manfred; Hocher, Berthold

2002-08-01

337

Smoking Cessation and Weight Gain.  

ERIC Educational Resources Information Center

Investigated determinants of weight gain after quitting smoking in two smoking treatment outcome studies. Results indicated abstinence resulted in weight gain, and postquitting weight gain was predicted by pretreatment tobacco use, a history of weight problems, and eating patterns. Relapse to smoking did not follow weight gain. (Author/BL)

Hall, Sharon M.; And Others

1986-01-01

338

One-photon and two-photon double-slit interference in spontaneous and stimulated parametric down-conversions  

NASA Astrophysics Data System (ADS)

We theoretically discuss two-photon double-slit interference for spontaneous and stimulated parametric down-conversions and compare it with one-photon case. We show that two-photon sub-wavelength interference can exist in a general interaction of spontaneous parametric down-conversion (SPDC) for both type I and type II crystals. In low gain SPDC, interference effect can be attributed to the previous study based on two-photon entangled state. But the important fact is that the sub-wavelength interference will not be washed out even if in very high gain SPDC, revealing the macroscopic nature. We propose an alternative scheme to observe sub-wavelength interference with a joint-intensity measurement, which occurs for a type I crystal in the high gain case. The theoretical analysis shows that the effect originates from classical thermal correlation. However, we also formulate the one-photon and two-photon double-slit interference in the stimulated process, and show amplified interference patterns.

Cao, De-Zhong; Li, Zhuan; Zhai, Yan-Hua; Wang, Kaige

2005-04-01

339

Gain control mechanisms in spinal motoneurons.  

PubMed

Motoneurons provide the only conduit for motor commands to reach muscles. For many years, motoneurons were in fact considered to be little more than passive "wires". Systematic studies in the past 25 years however have clearly demonstrated that the intrinsic electrical properties of motoneurons are under strong neuromodulatory control via multiple sources. The discovery of potent neuromodulation from the brainstem and its ability to change the gain of motoneurons shows that the "passive" view of the motor output stage is no longer tenable. A mechanism for gain control at the motor output stage makes good functional sense considering our capability of generating an enormous range of forces, from very delicate (e.g., putting in a contact lens) to highly forceful (emergency reactions). Just as sensory systems need gain control to deal with a wide dynamic range of inputs, so to might motor output need gain control to deal with the wide dynamic range of the normal movement repertoire. Two problems emerge from the potential use of the brainstem monoaminergic projection to motoneurons for gain control. First, the projection is highly diffuse anatomically, so that independent control of the gains of different motor pools is not feasible. In fact, the system is so diffuse that gain for all the motor pools in a limb likely increases in concert. Second, if there is a system that increases gain, probably a system to reduce gain is also needed. In this review, we summarize recent studies that show local inhibitory circuits within the spinal cord, especially reciprocal and recurrent inhibition, have the potential to solve both of these problems as well as constitute another source of gain modulation. PMID:25120435

Johnson, Michael D; Heckman, Charles J

2014-01-01

340

Spontaneous Emulsification-A Possible Mechanism for Enhanced Oil Recovery  

Microsoft Academic Search

Spontaneous emulsification will occur between a hydrocarbon phase and an aqueous solution of petroleum sulfonates if the sulfonate preferentially partitions into the oil phase. The displacement of residual oil, in laboratory core floods, at a small capillary number is significantly improved when spontaneous emulsification occurs; with the displacement efficiency being favored by high emulsion coalescence rates. The following subjects are

Cash R. L; J. L. Cayias; Michael Hayes; D. J. MacAllister; T. Schares; R. S. Schechter; W. H. Wade

1975-01-01

341

Spontaneous Bilateral Meningoencephalocoeles of the Temporal Bones  

PubMed Central

Spontaneous tegmen tympani defects are rare with even rarer bilateral cases. The symptoms are nonspecific; hence, a high index of suspicion is required to prevent serious intracranial complications. We present a case of spontaneous bilateral tegmen tympani defects with associated meningoencephalocoeles in a 54-year-old male who presented with the signs and symptoms of severe meningitis. After careful workup which included a lumbar puncture, CT and MRI scans, both defects were repaired using a middle fossa approach. The patient made an uneventful recovery with complete cessation of otorrhoea and improvement in his hearing. PMID:24288640

2013-01-01

342

Spontaneous recovery in dynamical networks  

NASA Astrophysics Data System (ADS)

Much research has been carried out to explore the structural properties and vulnerability of complex networks. Of particular interest are abrupt dynamic events that cause networks to irreversibly fail. However, in many real-world phenomena, such as brain seizures in neuroscience or sudden market crashes in finance, after an inactive period of time a significant part of the damaged network is capable of spontaneously becoming active again. The process often occurs repeatedly. To model this marked network recovery, we examine the effect of local node recoveries and stochastic contiguous spreading, and find that they can lead to the spontaneous emergence of macroscopic `phase-flipping' phenomena. As the network is of finite size and is stochastic, the fraction of active nodes z switches back and forth between the two network collective modes characterized by high network activity and low network activity. Furthermore, the system exhibits a strong hysteresis behaviour analogous to phase transitions near a critical point. We present real-world network data exhibiting phase switching behaviour in accord with the predictions of the model.

Majdandzic, Antonio; Podobnik, Boris; Buldyrev, Sergey V.; Kenett, Dror Y.; Havlin, Shlomo; Eugene Stanley, H.

2014-01-01

343

Spontaneous Reduction of Mononuclear High-Spin Iron(III) Complexes to Mononuclear Low-Spin Iron(II) Complexes in Aqueous Media and Nuclease Activity via Self-Activation.  

PubMed

Mononuclear high-spin [Fe(III) (Pyimpy)Cl3 ]?2?CH2 Cl2 (1?2?CH2 Cl2 ) and [Fe(III) (Me-Pyimpy)Cl3 ] (2), as well as low-spin Fe(II) (Pyimpy)2 ](ClO4 )2 (3) and [Fe(II) (Me-Pyimpy)2 ](ClO4 )2 (4) complexes of tridentate ligands Pyimpy and Me-Pyimpy have been synthesized and characterized by analytical techniques, spectral, and X-ray structural analyses. We observed an important type of conversion and associated spontaneous reduction of mono-chelated high-spin Fe(III) (1?2?CH2 Cl2 and 2) complexes to low-spin bis-chelated Fe(II) complexes 3 and 4, respectively. This process has been explored in detail by UV/Vis, fluorescence, and (1) H?NMR spectroscopic measurements. The high positive potentials observed in electrochemical studies suggested a better stabilization of Fe(II) centers in 3 and 4. Theoretical studies by density functional theory (DFT) calculations supported an increased stabilization for 3 in polar solvents. Self-activated nuclease activity of complexes 1?2CH2 Cl2 and 2 during their spontaneous reduction was examined for the first time and the mechanism of nuclease activity was investigated. PMID:25488050

Ghosh, Kaushik; Tyagi, Nidhi; Kumar Dhara, Ashish; Singh, Udai P

2014-12-01

344

[Fast food promotes weight gain].  

PubMed

The total amounts of fat in a fast food menu consisting of French fries and fried Chicken Nuggets from McDonald's and KFC, respectively, bought in 35 different countries vary from 41 to 71 gram. In most countries the menu contained unacceptably high amounts of industrially-produced trans fat which contributes to an increased risk of ischaemic heart disease, weight gain, abdominal fat accumulation and type 2 diabetes. The quality of the ingredients in fast food ought to be better and the size of the portions smaller and less energy-dense so that frequent fast food meals do not increase the risk of obesity and diseases among customers. PMID:17537359

Stender, Steen; Dyerberg, Jørn; Astrup, Arne V

2007-05-01

345

Assess the key physics that underpins high-hydro coupling-efficiency in NDCX-II experiments and high-gain heavy ion direct drive target designs using proven hydro codes like HYDRA  

SciTech Connect

The simulations provided in this milestone have solidified the theoretical underpinning of direct drive targets and also the ability to design experiments on NDCX II that will enhance our understanding of ion-beam hydrodynamic coupling, and thus be relevant to IFE. For the case of the IFE targets, we have studied hydro and implosion efficiency using HYDRA in ID, a starting point towards the goal of polar direct drive in geometry compatible with liquid wall chambers. Recent analysis of direct drive fusion energy targets using heavy ion beams has found high coupling efficiency of ion beam energy into implosion energy. However, to obtain optimal coupling, the ion energy must increase during the pulse in order to penetrate the outflowing ablated material, and deposit the energy close enough to the fuel so that the fuel achieves sufficient implosion velocity. We have computationally explored ID (radial) time dependent models of ion driven direct drive capsule implosions using the Arbitrary Lagrangian-Eulerian (ALE) code HYDRA, to help validate the theoretical analysis done so far, particularly exploring the effects of varying the ion energy and ion current over the course of the pulse. On NDCX II, experiments have been proposed to explore issues of ion penetration of the outflowing plasma over the course of the ion pulse. One possibility is to create a first pulse of ions that heats a planar target, and produces an outflow of material. A second pulse, {approx}10 ns after the first, of higher ion energy (and hence larger projected range) will interact with this outflow before reaching and further heating the target. We have investigated whether the change in range can be tailored to match the evolution of the ablation front. We have carried out simulations using the one-dimensional hydrodynamic code DISH and HYDRA to set parameters for this class of experiments. DISH was upgraded with an ion deposition algorithm, and we have carried out ID (planar) simulations. HYDRA was also used for ID (planar) and 2D (r,z) simulations of potential experiments. We have also explored whether similar physics could be studied using an energy ramp (i.e., a velocity tilt) rather than two separate pulses. We have shown that an optimum occurs in the macropulse duration (with fixed velocity tilt) that maximizes the shock strength. In the area of IFE target design we have continued to explore direct drive targets composed of deuterium-tritium fuel and ablator layers. We have extended our previous target designs at 0.44 MJ drive energy, gain 50, (50 MeV foot, 500 MeV main pulse, Rb ion, which requires a large number of beams due to a high beam space charge constraint) to a power plant scale 3.7 MJ drive energy, gain {approx}150 (220 MeV foot, 2.2 GeV main pulse, Hg ion) that eases requirements on the accelerator. We have studied the effects of two important design choices on ICF target performance. We have shown that increasing the number of foot pulses may reduce the target's in-flight adiabat and consequently improve its compressibility and fusion yield. As in the case of laser drive, the first three shocks are the most important to the target's performance, with additional shocks contributing only marginally to compression and burn. We have also demonstrated that ion range lengthening during the main pulse can further reduce the target adiabat and improve the efficiency with which beam energy is coupled into the target. (Ion range lengthening using two different kinetic energies for the foot and main pulse has previously proven effective in the design of high gain targets).

Barnard, J. J.; Hay, M. J.; Logan, B. G.; Ng, S. F.; Perkins, L. J.; Veitzer, S.; Yu, S. S.

2010-07-01

346

Nonlinear Output-Feedback Tracking Using High-gain Observer and Variable Structure Control * * An earlier version of this paper was presented at the 1995 IFAC Nonlinear Control Systems Design Symposium, held in Lake Tahoe, U.S.A. in June 1995. , 1 1 A globally bounded output-feedback variable structure controller with a high-gain observer is designed for a feedback-linearizable minimum-phase nonlinear system in the presence of unknown disturbance  

Microsoft Academic Search

We consider a single-input-single-output nonlinear system which can be represented by an input-output model. The system, which can be transformed into the normal form, is required to be minimum phase. The model contains unknown bounded disturbances. We assume that the reference signal and its derivatives are bounded. A high-gain observer is used to estimate derivatives of the tracking error while

SEUNGROHK OH; HASSAN K. KHALIL

1997-01-01

347

Spontaneous Thigh Compartment Syndrome  

PubMed Central

A young man presented with a painful and swollen thigh, without any history of trauma, illness, coagulopathic medication or recent exertional exercise. Preliminary imaging delineated a haematoma in the anterior thigh, without any fractures or muscle trauma. Emergent fasciotomies were performed. No pathology could be identified intra-operatively, or on follow-up imaging. A review of thigh compartment syndromes described in literature is presented in a table. Emergency physicians and traumatologists should be cognisant of spontaneous atraumatic presentations of thigh compartment syndrome, to ensure prompt referral and definitive management of this limb-threatening condition. PMID:21691491

Khan, Sameer K.; Thati, Srinivas; Gozzard, Charles

2011-01-01

348

Initial state angular asymmetries in high energy p+A collisions: Spontaneous breaking of rotational symmetry by a color electric field and C-odd fluctuations  

NASA Astrophysics Data System (ADS)

We present a simple model for generating initial-state azimuthal asymmetries in pA collisions from dipole scattering on an anisotropic dense target. Parity even angular harmonics arise from the C-even real part of the dipole S-matrix which spontaneously breaks rotational symmetry in two dimensions due to a condensate for the color electric field. This leads to an angular correlation with the direction of E ? . Parity odd harmonics are generated by the C-odd imaginary part (odderon) due to coupling to coherent target fluctuations which again break rotational invariance. We perform a first qualitative extraction of the amplitude and cutoff of C-odd fluctuations in the dense target.

Dumitru, Adrian; Giannini, Andre V.

2015-01-01

349

High Current Gain In0.49Ga0.51P/GaAs Heterojunction Bipolar Transistors with Double Spacers Grown by Gas Source Molecular Beam Epitaxy  

NASA Astrophysics Data System (ADS)

This paper reports the improved performance of the lattice-matched N-p+-n In0.49Ga0.51P/GaAs heterojunction bipolar transistors(HBTs) with undoped spacers grown by the gas source molecular beam epitaxy. A 600 Å GaAs base doped with beryllium at 3×1019 cm-3 and a 1000 Å In0.49Ga0.51P emitter doped with silicon at 3×1017 cm-3 have been grown. On both sides of the base, the 50 Å undoped GaAs spacers were grown. Devices with emitter area of 100 × 100 ?m2 were fabricated by using selective wet chemical etching technique. The measured results of HBTs reveal good junction characteristics, and the common-emitter current gain reaches 320 at the collector current density of 280 A/cm2.

Chen, Xiao-Jie; Chen, Jian-Xin; Chen, Yi-Qiao; Peng, Peng; Yang, Quan-Kui; Li, Ai-Zhen

2000-12-01

350

Spontaneous Pneumomediastinum with Concurrent Pneumorrhachis  

PubMed Central

Spontaneous pneumomediastinum is a very uncommon entity that is defined as the presence of free air in the mediastinum without an obvious etiology. The presence of air in the spinal canal, known as concurrent pneumorrhachis, is an extremely rare epiphenomenon of spontaneous pneumomediastinum. We report a rare case of spontaneous pneumomediastinum with pneumorrhachis associated with influenza. The patient was diagnosed without invasive procedures, was managed with supportive treatment, and recovered without any complications.

Jung, Hanna; Lee, Sang Cjeol; Lee, Deok Heon; Kim, Gun-Jik

2014-01-01

351

Controlling gain one photon at a time  

PubMed Central

Adaptation is a salient property of sensory processing. All adaptational or gain control mechanisms face the challenge of obtaining a reliable estimate of the property of the input to be adapted to and obtaining this estimate sufficiently rapidly to be useful. Here, we explore how the primate retina balances the need to change gain rapidly and reliably when photons arrive rarely at individual rod photoreceptors. We find that the weakest backgrounds that decrease the gain of the retinal output signals are similar to those that increase human behavioral threshold, and identify a novel site of gain control in the retinal circuitry. Thus, surprisingly, the gain of retinal signals begins to decrease essentially as soon as background lights are detectable; under these conditions, gain control does not rely on a highly averaged estimate of the photon count, but instead signals from individual photon absorptions trigger changes in gain. DOI: http://dx.doi.org/10.7554/eLife.00467.001 PMID:23682314

Schwartz, Gregory W; Rieke, Fred

2013-01-01

352

Amplified spontaneous emission (ASE) models and approximations for thin-disk laser modeling  

NASA Astrophysics Data System (ADS)

It is well-known that amplified spontaneous emission (ASE) can be a major source of upper laser level loss in high gain pulsed or steady-state solid state lasers. This paper briefly reviews the theory of ASE and, using a simple rate equation model of the upper laser level, a geometric, radiative transport equation to describe the ASE intensity, and the perturbation method of multiple time scales, demonstrates that the loss rate of the upper laser level due to ASE adiabatically follows the spontaneous emission source term. This result which includes gain saturation is applicable to both quasi-three level and four level lasers and rigorously justifies formally using the steady-state expression derived heuristically by Lowenthal and Eggleston1 to model ASE loss in pulsed laser media. Then, it is shown that the frequency integral occurring in the ASE loss term can be evaluated analytically for both a broad "flat-top" and a Lorentzian stimulated emission lineshape but must be evaluated numerically or using an approximation due to Tommasini and Balmer2 for a Gaussian stimulated emission lineshape. It is shown that at high gain loss due to ASE is mitigated by ASE line narrowing. For a thin disk laser an approximate expression for the rate of ASE loss (or ASE lifetime) can be obtained by evaluating the remaining volume integral using either the method of Speiser3 or of Vretenar et al4. A new approximate expression for the ASE loss rate is obtained which, unlike Speiser's3 expression, accounts for ASE line narrowing and, unlike Vretenar et al's4 expression, correctly scales with the cylindrical volume of the disk. Application to both 1D and 3D laser modeling is briefly discussed.

Copeland, Drew A.

2013-03-01

353

Body Weight, Not Insulin Sensitivity or Secretion, May Predict Spontaneous Weight Changes in Nondiabetic and Prediabetic Subjects  

PubMed Central

OBJECTIVE Previous studies have found that high insulin sensitivity predicts weight gain; this association has not been confirmed. Our aim was to systematically analyze metabolic predictors of spontaneous weight changes. RESEARCH DESIGN AND METHODS In 561 women and 467 men from the Relationship Between Insulin Sensitivity and Cardiovascular Disease (RISC) cohort (mean age 44 years, BMI range 19–44 kg/m2, 9% impaired glucose tolerance) followed up for 3 years, we measured insulin sensitivity (by a euglycemic clamp) and ?-cell function (by modeling of the C-peptide response to oral glucose and by acute insulin response to intravenous glucose). RESULTS Insulin sensitivity was similar in weight gainers (top 20% of the distribution of BMI changes), weight losers (bottom 20%), and weight stable subjects across quartiles of baseline BMI. By multiple logistic or linear regression analyses controlling for center, age, sex, and baseline BMI, neither insulin sensitivity nor any ?-cell function parameter showed an independent association with weight gain; this was true in normal glucose tolerance, impaired glucose tolerance, and whether subjects progressed to dysglycemia or not. Baseline BMI was significantly higher in gainers (26.1 ± 4.1 kg/m2) and losers (26.6 ± 3.7 kg/m2) than in weight stable subjects (24.8 ± 3.8 kg/m2, P < 0.0001 for both gainers and losers). Baseline waist circumference (or equivalently, BMI or weight) was a positive, independent predictor of both weight gain and weight loss (odds ratio 1.48 [95% CI 1.12–1.97]) in men and (1.67 [1.28–2.12]) in women. In men only, better insulin sensitivity was an additional independent predictor of weight loss. CONCLUSIONS Neither insulin sensitivity nor insulin secretion predicts spontaneous weight gain. Individuals who have attained a higher weight are prone to either gaining or losing weight regardless of their glucose tolerance. PMID:21617179

Rebelos, Eleni; Muscelli, Elza; Natali, Andrea; Balkau, Beverley; Mingrone, Geltrude; Piatti, Piermarco; Konrad, Thomas; Mari, Andrea; Ferrannini, Ele

2011-01-01

354

Weight Gain Prevention among Women  

Microsoft Academic Search

Objective: Women 25 to 45 years old are at risk for weight gain and future obesity. This trial was designed to evaluate the efficacy of two interventions relative to a control group in preventing weight gain among normal or overweight women and to identify demographic, behavioral, and psychosocial factors related to weight gain prevention.Research Methods and Procedures: Healthy women (N

Michele D. Levine; Mary Lou Klem; Melissa A. Kalarchian; Rena R. Wing; Lisa Weissfeld; Li Qin; Marsha D. Marcus

2007-01-01

355

Chimeric lactase capable of spontaneous and strong immobilization on cellulose and development of a continuous-flow system for lactose hydrolysis at high temperatures.  

PubMed

Recombinant plasmids containing fusion proteins composed of two different modules were constructed and expressed in Escherichia coli. The modules encoded the lactase LacA (LacZ) from the thermophilic bacterium Thermoanaerobacter ethanolicus and the cellulase CelD, a cellulose-binding module (CBM) from Anaerocellum thermophilum. The CelD CBM provides a spontaneous and strong sorption of the fusion proteins onto a cellulose carrier. The enzymatic activities of both the free LacA protein and LacA-CelD CBM fusion proteins immobilized onto the cellulose carrier were assessed. The LacA activity of the fusion protein was dependent upon its position with respect to the CBM. The highest level of lactase activity and stability was observed when the lactase domain was localized at its N terminus. A continuous-flow column reactor of lactase immobilized on a cellulose carrier was constructed, and its activity was assessed. The lactose hydrolysis rate for a 150 mM (5%) solution at a flow rate of 1 reactor volume per min was 75%, which is a value optimal for further whey transformation into glucose/galactose syrup. PMID:20935120

Velikodvorskaya, G A; Tikhonova, T V; Gurvits, I D; Karyagina, A S; Lavrova, N V; Sergienko, O V; Tashlitskii, V N; Lunina, N A; Lunin, V G

2010-12-01

356

Isolation and molecular characterization of high-performance cellobiose-fermenting spontaneous mutants of ethanologenic Escherichia coli KO11 containing the Klebsiella oxytoca casAB operon.  

PubMed Central

Escherichia coli KO11 was previously constructed to produce ethanol from acid hydrolysates of hemicellulose (pentoses and hexoses) by the chromosomal integration of Zymomonas mobilis genes encoding pyruvate decarboxylase (pdc) and alcohol dehydrogenase (adhB). Klebsiella oxytoca P2 was constructed in an analogous fashion for the simultaneous saccharification and fermentation of cellulose and contains PTS enzymes for cellobiose. In this study, KO11 was further engineered for the fermentation of cellulose by adding the K. oxytoca casAB genes encoding Enzyme IIcellobiose and phospho-beta-glucosidase. Although the two K. oxytoca genes were well expressed in cloning hosts such as DH5 alpha, both were expressed poorly in E. coli KO11, a derivative of E. coli B. Spontaneous mutants which exhibited more than 15-fold-higher specific activities for cellobiose metabolism were isolated. The mutations of these mutants resided in the plasmid rather than the host. Three mutants were characterized by sequence analysis. All contained similar internal deletions which eliminated the casAB promoter and operator regions and placed the lacZ Shine-Dalgarno region immediately upstream from the casA Shine-Dalgarno region. KO11 harboring mutant plasmids (pLOI1908, pLOI1909, or pLOI1910) rapidly fermented cellobiose to ethanol, and the yield was more than 90% of the theoretical yield. Two of these strains were used with commercial cellulase to ferment mixed-waste office paper to ethanol. PMID:9406380

Moniruzzaman, M; Lai, X; York, S W; Ingram, L O

1997-01-01

357

Model-based characterization of ventilatory stability using spontaneous breathing  

PubMed Central

Cyclic ventilatory instabilities are widely attributed to an increase in the sensitivity or loop gain of the chemoreflex feedback loop controlling ventilation. A major limitation in the conventional characterization of this feedback loop is the need for labor-intensive methodologies. To overcome this limitation, we developed a method based on trivariate autoregressive modeling using ventilation, end-tidal Pco2 and Po2; this method provides for estimation of the overall “loop gain” of the respiratory control system and its components, chemoreflex gain and plant gain. Our method was applied to recordings of spontaneous breathing in 15 anesthetized, tracheostomized, newborn lambs before and after administration of domperidone (a dopamine D2-receptor antagonist that increases carotid body sensitivity). We quantified the known increase in hypoxic ventilatory sensitivity in response to domperidone; controller gain for O2 increased from 0.06 (0.03, 0.09) l·min?1·mmHg?1 to 0.09 (0.08, 0.13) l·min?1·mmHg?1; median (interquartile-range). We also report that domperidone increased the loop gain of the control system more than twofold [0.14 (0.12, 0.22) to 0.40 (0.15, 0.57)]. We observed no significant changes in CO2 controller gain, or plant gains for O2 and CO2. Furthermore, our estimate of the cycle duration of periodic breathing compared favorably with that observed experimentally [measured: 7.5 (7.2, 9.1) vs. predicted: 7.9 (7.0, 9.2) breaths]. Our results demonstrate that model-based analysis of spontaneous breathing can 1) characterize the dynamics of the respiratory control system, and 2) provide a simple tool for elucidating an individual's propensity for ventilatory instability, in turn allowing potential therapies to be directed at the underlying mechanisms. PMID:21474696

Edwards, Bradley A.; Sands, Scott A.; Berger, Philip J.; Wellman, Andrew; Verghese, George C.; Malhotra, Atul; Butler, James P.

2011-01-01

358

Spontaneous coronary artery dissection.  

PubMed

Spontaneous coronary artery dissection is a rarely identified entity whose exact incidence, etiology, pathogenesis, medium-term evolution, and optimal treatment have not yet been firmly established. This article describes five new cases with additional specific characteristics. Five of 2,241 coronary arteriograms taken between September 1989 and November 1992 showed angiographic signs of coronary dissection. Three of the patients were treated pharmacologically, and two were operated on. All were evaluated angiographically 10-18 months after diagnosis and followed up clinically for > or = 20 months. Three patients exhibited acute myocardial infarction, one showed effort angina and the fifth unstable angina. In four cases, coronary dissection was associated with coronary atherosclerosis, but in the fifth the coronary tree was apparently healthy except for the dissection. Dissection affected the right coronary artery in three cases and the left in two. Angiographic evolution varied among the five and was uncorrelated with treatment. Dissection disappeared in three; it persisted, with total obstruction of the artery in the middle of the dissected segment in one case; and advanced to affect the whole left coronary tree in the fifth. After an 18-month follow-up, none of the five patients experienced symptoms. These cases provide a good illustration of the variability of spontaneous coronary dissection as regards etiology, clinical presentation, treatment, and evolution. Coronary dissection is always caused by hemorrhage in the media of the arterial wall; its variability in evolution and in optimal treatment may be derived from the cause of the hemorrage, which possibly was not the same in all cases. PMID:8039214

Pasalodos Pita, J; Vazquez Gonzalez, N; Perez Alvarez, L; Vazquez Rodriguez, J M; Castro Beiras, A

1994-05-01

359

Gain and energy storage in holmium YLF  

NASA Technical Reports Server (NTRS)

It is demonstrated that Q-switched holmium lasers are capable of high-gain and high-energy operation at 300 K. Small-signal gain coefficients of 0.50 and 0.12/cm have been measured in YLF and YAG, respectively. Small-signal gains of 0.50/cm are comparable to those achievable in Nd:YAG and are not typical of low-gain materials. This large gain in the Ho:YLF material is made possible by operating the amplifier in the ground state depletion mode. The amplifier performance data and associated analysis presented demonstrate that efficient energy storage is possible with very high excited state ion densities of the Ho 5I7 upper laser level. This is an important result since upconversion can limit the 5I7 population. Although upconversion was still present in this experiment, it was possible to achieve efficient energy storage, demonstrating that the problem is manageable even at high excitation densities in YLF.

Storm, Mark E.; Deyst, John P.

1991-01-01

360

Acute Spontaneous Spinal Epidural Hematoma  

Microsoft Academic Search

BACKGROUND AND PURPOSE:Although previous reports have characterized MR imaging features of spinal epidural hematomas (EDH), few cases have been reported during the acute or hyperacute phase within the first 48 hours. Our goal in this investigation was to correlate the MR imaging features of acute (#48 hours) spontaneous EDH with clinical management and outcome. METHODS: Eight patients with acute spontaneous

R. D. Henderson; Amar S. Swarnkar; Robert L. Williams

2001-01-01

361

Acting to gain information  

NASA Technical Reports Server (NTRS)

This report is concerned with agents that act to gain information. In previous work, we developed agent models combining qualitative modeling with real-time control. That work, however, focused primarily on actions that affect physical states of the environment. The current study extends that work by explicitly considering problems of active information-gathering and by exploring specialized aspects of information-gathering in computational perception, learning, and language. In our theoretical investigations, we analyzed agents into their perceptual and action components and identified these with elements of a state-machine model of control. The mathematical properties of each was developed in isolation and interactions were then studied. We considered the complexity dimension and the uncertainty dimension and related these to intelligent-agent design issues. We also explored active information gathering in visual processing. Working within the active vision paradigm, we developed a concept of 'minimal meaningful measurements' suitable for demand-driven vision. We then developed and tested an architecture for ongoing recognition and interpretation of visual information. In the area of information gathering through learning, we explored techniques for coping with combinatorial complexity. We also explored information gathering through explicit linguistic action by considering the nature of conversational rules, coordination, and situated communication behavior.

Rosenchein, Stanley J.; Burns, J. Brian; Chapman, David; Kaelbling, Leslie P.; Kahn, Philip; Nishihara, H. Keith; Turk, Matthew

1993-01-01

362

Gain without inversion for gamma radiation  

NASA Astrophysics Data System (ADS)

Gain without inversion for a level-mixing scheme is studied for gamma-optics. In this scheme nuclear level mixing is created by misalignment of a dc magnetic field with respect to the c-axis of a noncubic crystal. Axially symmetric electron nuclear coupling and nuclear quadrupole interaction with an electric field gradient produce two electro-nuclear levels that are equally mixed and split, with the energy gap dependent on the tilting angle of the magnetic field. By laser excitation of an electron transition, nuclear spin coherence can be created between these two levels. A condition is found for the predominant population of the dark state by spontaneous emission. This state is a particular superposition of the mixed states, such that, by selection rules, the transition from it cannot be excited by ?-radiation. If all absorbing nuclei are in the dark state, resonant ?-absorption is suppressed in the sample. At the same condition, ?-emission of the excited nuclei is allowed because the corresponding transition terminates in another component of the mixed states superposition. The constraints on the tilting angle and reciprocal gap between two mixed electro-nuclear levels are found, setting the limits to these values beyond which the gain without inversion becomes impossible.

Shakhmuratov, R. N.; Kozyreff, G.; Coussement, R.; Odeurs, J.; Mandel, P.

2000-05-01

363

Enhancing optical gains in Si nanocrystals via hydrogenation and cerium ion doping  

NASA Astrophysics Data System (ADS)

We report optical gain enhancements in Si nanocrystals (Si-NCs) via hydrogenation and Ce3+ ion doping. Variable stripe length technique was used to obtain gains. At 0.3 W/cm2 pumping power density of pulsed laser, net gains were observed together with gain enhancements after hydrogenation and/or Ce3+ ion doping; gains after loss corrections were between 89.52 and 341.95 cm-1; and the photoluminescence (PL) lifetime was found to decrease with the increasing gain enhancement. At 0.04 W/cm2 power density, however, no net gain was found and the PL lifetime increased with the increasing PL enhancement. The results were discussed according to stimulated and spontaneous excitation and de-excitation mechanisms of Si-NCs.

Wang, Dong-Chen; Chen, Jia-Rong; Li, Yan-Li; Song, Sheng-Chi; Guo, Wen-Ping; Lu, Ming

2014-07-01

364

JOURNAL DE PHYSIQUE CoZZoque C9, suppl6ment au nO1l, Tome 41, novembre 2980, page C9-203 THE HIGH GAIN C02 LASER BY EFFECTIVE MIXING OF N2 AND C02 GAS  

E-print Network

GAIN C02 LASER BY EFFECTIVE MIXING OF N2 AND C02 GAS H. Hara and A. Fujisawa. First Research Center Japan Defense Agency, Nakameguro, 2-2-1, Meguro, Tokyo, Japan. Abstract.- A high-gain C02 laser published in the literature on C02 laser '4 which used a discharse in N2-He -CO mixture gas, however2

Boyer, Edmond

365

Nonimaging Optical Gain in Luminescent Concentration through Photonic Control of Emission Etendue  

E-print Network

: luminescence, solar concentration, nonimaging optics, microcavity, spontaneous emission, photovoltaics, requires geometric solar concentrators to track the Sun in order to reach high concentration ratio (CR

Rogers, John A.

366

Spontaneous Circumrenal Hæmatoma  

PubMed Central

By spontaneous circum-renal hæmatoma is meant a condition of extensive extravasation of blood into the kidney bed and surrounding tissues, unassociated with trauma. Since this is manifested by a fairly uniform clinical picture, by similar operative findings, and by peculiar difficulties in treatment, I propose to discuss it as a clinical entity irrespective of its wide ultimate causation. Very few cases are reported in the English literature. Nevertheless, from the world literature I have collected 170 case reports, and on them, together with three further cases, I base the present paper. Etiologically the cases fall into three groups:— (1) Those due to definite disease of the kidney or its blood-vessels, 58%. (2) Those due to extra-renal causes, 22%. (3) Those cases whose cause is obscure, 20%. In the first group neoplasms and inflammations of the kidney, aneurysms of the renal artery and arteriosclerosis are obvious causes. Many cases are due to obstruction of the renal veins. The classical triad of abdominal pain, signs of internal hæmorrhage, and a tumour in the loin are often obscured by the resemblance of an acute abdominal catastrophe. In acute cases, expectant treatment is almost invariably fatal. Evacuation of the clot, tamponage and drainage has a mortality of about 40%, whilst nephrectomy in 55 cases showed a mortality of 22%. ImagesFig. 1Fig. 2Fig. 3 PMID:19989861

Heritage, Kenneth

1934-01-01

367

Lower weight gain and hepatic lipid content in hamsters fed high fat diets supplemented with white rice protein, brown rice protein, and soy protein and their hydrolysates  

Technology Transfer Automated Retrieval System (TEKTRAN)

The physiological effects of the hydrolysates from white rice, brown rice, and soy isolate were compared to the original protein source. White rice, brown rice, and soy protein were hydrolyzed with the food grade enzyme, alcalase2.4 L®. Male Syrian hamsters were fed high-fat diets containing eithe...

368

What Does "Highly Qualified" Mean for Student Achievement? Evaluating the Relationships between Teacher Quality Indicators and At-Risk Students' Mathematics and Reading Achievement Gains in First Grade  

ERIC Educational Resources Information Center

Policymakers and researchers continue to search for ways to improve K-12 education, which has led to an increased focus on teacher quality as an impetus for educational improvement. As such, current legislation under No Child Left Behind (NCLB) calls for highly qualified teachers in every classroom. But are the characteristics associated with…

Phillips, Kristie J. R.

2010-01-01

369

Observation of Spontaneous Circulation in a Confined Bacterial Suspension  

NASA Astrophysics Data System (ADS)

The individual swimming behavior of many microorganisms is often well described by a run-and-tumble model. However steric and fluid interactions with other cells and boundaries can strongly affect this behavior. At high concentrations, rod-like bacteria are known to exhibit self-organization reminiscent of nematic liquid crytal ordering, except with polar alignment. Depending on the experimental conditions different large scale patterns can arise such as vortices, jets, plumes and swarms. We use the model organism Bacillus subtilis to study the effect of a quasi-2D confinement on their large scale organization. Bacteria are concentrated in flattened drops surrounded by oil. Using fluorescent microsphere tracers and particle image velocimetry, we measure the flow of the cells and of the suspending fluid inside and outside of the drop. For drop diameters ranging from 10 to 100 ?m and 20 ?m in height, the suspension displays spontaneous circulation in the form of a single vortex, which, for the largest drops, significantly exceeds the size of swirls in the unconfined system. Moreover we observe a striking backward flow close to the boundary. We compare these results with a theoretical analysis to gain insights into the assembly and stability of such patterns.

Wioland, Hugo; Goldstein, Raymond

2013-03-01

370

Radiative recombination and optical gain spectra in biaxially strained n-type germanium  

NASA Astrophysics Data System (ADS)

We calculate band-to-band radiative transition rate spectra in pure Ge as functions of applied tensile strain, heavy doping, charge injection density, and temperature. Direct and indirect phonon-assisted transitions are considered. Deformation potential theory is adopted to describe the conduction and valence near-gap edges. Biaxial strain has required appropriate treatment of system anisotropy through the evaluation of the mass tensor components for the different bands involved in the studied transitions. Population distribution in the ? and L conduction valleys and in the valence states near ? have been evaluated accordingly considering the degeneracy condition of the sample, induced by high doping and high injection charge density. Also the effect of strain on the dipole matrix elements have been properly taken into account. The energy-resolved near-infrared spontaneous recombination spectra and the TE and TM polarized absorption/gain spectra have been obtained for a broad range of n-type doping, strain values, and excitation densities. We conclude that, despite the free carrier losses, net gain values as high as 6000 cm-1, are achievable for doping density and strain values reported in the literature.

Virgilio, M.; Manganelli, C. L.; Grosso, G.; Pizzi, G.; Capellini, G.

2013-06-01

371

Thermal noise analysis of multi-bit SC gain-stages for low-voltage high-resolution pipeline ADC design  

Microsoft Academic Search

Analysis of thermal noise in switche&capacitor multi-bit gainstages used in low-voltage high-resolution pipeline analog-todigital converters is presented. The analytical expression obtained for the input refmed noise power, which should be' considered in the design procedure, is general for any number of bits being resolved and shows that the noise power is decreased whet, more bits are resolved in the stage.

M. Y. Azizi; A. Saeedfar; H. Z. Hoseini; O. Shoaei

2003-01-01

372

Numerical investigation of concrete subjected to compressive impact loading. Part 1: A fundamental explanation for the apparent strength gain at high loading rates  

Microsoft Academic Search

This study investigates the response of structural concrete to high rates of loading. The research is based on a finite-element (FE) program capable of carrying out three-dimensional (3D) nonlinear static and dynamic analyses which has been found to be capable of yielding realistic predictions to the response of plain- and reinforced-concrete structures under arbitrary static and dynamic actions. The FE

D. M. Cotsovos; M. N. Pavlovi?

2008-01-01

373

Brillouin optical correlation domain analysis with 4 millimeter resolution based on amplified spontaneous emission.  

PubMed

A new technique for Brillouin scattering-based, distributed fiber-optic measurements of temperature and strain is proposed, analyzed, simulated, and demonstrated. Broadband Brillouin pump and signal waves are drawn from the filtered amplified spontaneous emission of an erbium-doped fiber amplifier, providing high spatial resolution. The reconstruction of the position-dependent Brillouin gain spectra along 5 cm of a silica single-mode fiber under test, with a spatial resolution of 4 mm, is experimentally demonstrated using a 25 GHz-wide amplified spontaneous emission source. A 4 mm-long localized hot spot is identified by the measurements. The uncertainty in the reconstruction of the local Brillouin frequency shift is ± 1.5 MHz. The single correlation peak between the pump and signal is scanned along a fiber under test using a mechanical variable delay line. The analysis of the expected spatial resolution and the measurement signal-to-noise ratio is provided. The measurement principle is supported by numerical simulations of the stimulated acoustic field as a function of position and time. Unlike most other Brillouin optical correlation domain analysis configurations, the proposed scheme is not restricted by the bandwidth of available electro-optic modulators, microwave synthesizers, or pattern generators. Resolution is scalable to less than one millimeter in highly nonlinear media. PMID:24921326

Cohen, Raphael; London, Yosef; Antman, Yair; Zadok, Avi

2014-05-19

374

Ethanol extract of Liuwei Dihuang reduces weight gain and visceral fat in obese-prone CD rats fed a high-fat diet.  

PubMed

The current study investigated the effect and mechanisms of action of Liuwei Dihuang ethanol extract (LWDH-EE) on obesity and related metabolic phenotypes in male obese-prone CD rats. The rats were fed a high-fat diet and treated with 0 (obese control), 350 (EE350), or 700 (EE700) mg/kg/d of LWDH-EE in water once a day by gavage feeding for 10 weeks. The EE700 decreased body weight after 3 weeks of the treatment and the effect was maintained throughout the remaining study period. The EE700 also significantly reduced visceral fat and improved metabolic phenotypes by lowering the serum total cholesterol (T-C), non-high-density lipoprotein cholesterol, triacylglycerol, free fatty acids (FFA), and leptin levels. The EE350 reduced epididymal fat, serum T-C, and FFA but did not significantly affect other parameters. LWDH-EE dose-dependently increased fat and carbohydrate oxidations, energy expenditure, and the relative efficiency of fat oxidation for energy expenditure. EE350 and EE700 reduced food intake only in week 5 and did not affect the accumulative food intake in every week and the entire treatment period. Taken together, the results suggest that LWDH-EE is a potential therapeutic agent for the prevention of obesity possibly through a primary action of increasing energy metabolism and expenditure, along with a possible effect of decreasing energy intake. PMID:24603076

Nair, Sandhya Vg; Zhang, Junzeng; Wang, Yanwen

2014-05-01

375

Spontaneous olfactory receptor neuron activity determines follower cell response properties  

PubMed Central

Noisy or spontaneous activity is common in neural systems and poses a challenge to detecting and discriminating signals. Here we use the locust to answer fundamental questions about noise in the olfactory system: Where does spontaneous activity originate? How is this activity propagated or reduced throughout multiple stages of neural processing? What mechanisms favor the detection of signals despite the presence of spontaneous activity? We found that spontaneous activity long observed in the secondary projection neurons (PNs) originates almost entirely from the primary olfactory receptor neurons (ORNs) rather than from spontaneous circuit interactions in the antennal lobe, and that spontaneous activity in ORNs tonically depolarizes the resting membrane potentials of their target PNs and local neurons (LNs), and indirectly tonically depolarizes tertiary Kenyon cells (KCs). However, because these neurons have different response thresholds, in the absence of odor stimulation, ORNs and PNs display a high spontaneous firing rate but KCs are nearly silent. Finally, we used a simulation of the olfactory network to show that discrimination of signal and noise in the KCs is best when threshold levels are set so that baseline activity in PNs persists. Our results show how the olfactory system benefits from making a signal detection decision after a point of maximal information convergence, e.g., after KCs pool inputs from many PNs. PMID:22357872

Joseph, Joby; Dunn, Felice A.; Stopfer, Mark

2012-01-01

376

Spontaneous olfactory receptor neuron activity determines follower cell response properties.  

PubMed

Noisy or spontaneous activity is common in neural systems and poses a challenge to detecting and discriminating signals. Here we use the locust to answer fundamental questions about noise in the olfactory system: Where does spontaneous activity originate? How is this activity propagated or reduced throughout multiple stages of neural processing? What mechanisms favor the detection of signals despite the presence of spontaneous activity? We found that spontaneous activity long observed in the secondary projection neurons (PNs) originates almost entirely from the primary olfactory receptor neurons (ORNs) rather than from spontaneous circuit interactions in the antennal lobe, and that spontaneous activity in ORNs tonically depolarizes the resting membrane potentials of their target PNs and local neurons (LNs) and indirectly tonically depolarizes tertiary Kenyon cells (KCs). However, because these neurons have different response thresholds, in the absence of odor stimulation, ORNs and PNs display a high spontaneous firing rate but KCs are nearly silent. Finally, we used a simulation of the olfactory network to show that discrimination of signal and noise in the KCs is best when threshold levels are set so that baseline activity in PNs persists. Our results show how the olfactory system benefits from making a signal detection decision after a point of maximal information convergence, e.g., after KCs pool inputs from many PNs. PMID:22357872

Joseph, Joby; Dunn, Felice A; Stopfer, Mark

2012-02-22

377

Radiotherapy combined with hormonal therapy (RT-HT) in prostate cancer patients with low, intermediate, and high risk of biochemical recurrence: perspective and therapeutic gain analysis.  

PubMed

Treatment of prostate cancer (PC) is a challenge for both urologists and radiation oncologists. Currently, two radical methods of treatment are recommended in localized prostate cancer (PC)--i.e. radical prostatectomy (RP) and radiotherapy (RT) with excellent long-term results. However, the outcome of RT, which is the treatment of choice in locally advanced stages of the disease, is unsatisfactory due to the high risk of regional or distant metastases and local failure. Lately, hormonal therapy (HT), which had mainly been indicated for treatment of patients with distant metastases, has been added to radiotherapy to improve the efficacy of treatment. The general rationales for combining RT and HT are four-fold: decreasing prostate gland volume, diminishing the number of cancer cells, improving tumor oxygenation, and eliminating distant and regional micrometastases. Over the last 20 years several randomized clinical trials evaluating the results of combined HT and RT treatment have been carried out. The RTOG 85-31, RTOG 86-10, EORTC 22863 and RTOG 92-02 trials were completed from the mid 80s to the mid 90s and long-term follow-up data on all important end-points are now available. These data have been evaluated by panels of experts and served as the basis for the latest American (NCCN 2005) and European (EAU 2005) recommendations on prostate cancer. However, despite the long-term results of these trials, there are still no clear-cut answers to the following crucial questions: What is the optimal timing of hormonal therapy? What types of patients can benefit most from combined strategies? What is the spectrum and potential reversibility of side effects of long-term combined treatment? How does it influence the patients quality of life and care costs? Other questions concern the possible role of androgen deprivation therapy combined with brachytherapy. The only randomized trial to evaluate this issue to date was stopped due to incomplete accrual. Therefore, answers must be sought in the large body of nonrandomized studies. There is a constant need for properly designed randomized clinical trials to precisely identify the subgroup of patients who will benefit most from combined RT and HT treatment. Results of ongoing clinical trials (RTOG 9901, RTOG 9408) are expected to yield some answers to the questions mentioned above. Currently, we can conclude that in the group of patients with high risk of relapse (T3 or GS > 7 or PSA >20 ng/ml), combined hormonal and radiation therapy improves prostate cancer treatment results and should be highly recommended. PMID:17203887

Milecki, P; Kwias, Z; Martenka, D J J

2007-01-01

378

The Relationship among Spontaneity, Impulsivity, and Creativity  

ERIC Educational Resources Information Center

The present study was designed to investigate two characteristics of spontaneity, its relationship to creativity and to impulsivity. We hypothesized a positive relationship between spontaneity and creativity, consistent with Moreno, 1953 "canon of spontaneity-creativity." We also predicted a negative relationship between spontaneity and…

Kipper, David A.; Green, Doreen J.; Prorak, Amanda

2010-01-01

379

ASTER Urgent Response to the 2006 Eruption of Augustine Volcano, Alaska: Science and Decision Support Gained From Frequent High-resolution, Satellite Thermal Infrared Imaging of Volcanic Events  

NASA Astrophysics Data System (ADS)

Augustine Volcano, Alaska explosively erupted on January 11, 2006 after nearly eight months of increasing seismicity, deformation, gas emission, and small phreatic explosions. The volcano produced a total of 13 explosive eruptions during the last three weeks of January 2006. A new summit lava dome and two short, blocky lava flows grew during February and March 2006. A series of 7 daytime and 15 nighttime Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) scenes were acquired in response to this new activity. This response was facilitated by a new ASTER Urgent Request Protocol system. The ASTER data provided several significant observations as a part of a much larger suite of real-time or near-real-time data from other satellite (AVHRR, MODIS), airborne (FLIR, visual, gas), and ground-based (seismometers, radiometers) sensors used at the Alaska Volcano Observatory (AVO). ASTER is well-suited to volcanic observations because of its 15-m to 90-m spatial resolution, its ability to be scheduled and point off-nadir, and its ability to collect visible-near infrared (VNIR) to thermal infrared (TIR) data during both the day and night. Aided by the volcano's high latitude (59.4°N) ASTER was able to provide frequent repeat imaging as short as one day between scenes with an average 6-day repeat during the height of activity. These data provided a time series of high-resolution VNIR, shortwave infrared (SWIR - detects temperatures from about 200°C to > 600°C averaged over a 30-m pixel), and TIR (detects temperatures up to about 100°C averaged over a 90-m pixel) data of the volcano and its eruptive products. Frequent satellite imaging of volcanoes is necessary to record rapid changes in activity and to avoid recurring cloud cover. Of the 22 ASTER scenes acquired between October 30, 2005 and May 30, 2006, the volcano was clear to partly cloudy in 13 scenes. The most useful pre-eruption ASTER Urgent Request image was acquired on December 20. These data showed a broad area of slightly elevated TIR radiances that correlated with new snow-free areas and fumaroles at the summit. Thin cirrus cloud cover prevented quantitative TIR temperature extraction. During the night of February 1, 2006, ASTER imaged an ash-rich plume and fresh pyroclastic-flow deposits near the end of a 6-day continuous phase of the eruption. A decorrelation stretch of ASTER TIR bands 14, 13, and 11 suggests that the eruption plume was a mixture of ash and SO2. The 90-m TIR sensor was able to detect subtle surface radiance differences between the cooler distal ends of the pyroclastic-flow deposits and the warmer proximal areas. These temperature differences were controlled by both the age (hours) and thickness of the deposits. The SWIR data show a region of ~ 700 m x 300 m of hot pixels centered at the summit dome with a maximum brightness temperature of 619°C. ASTER data spanning February 22 through March 14 documented the continued growth of the summit domes and lava flows and gradual cooling of the block and ash deposits.

Wessels, R. L.; Ramsey, M. S.; Schneider, D. S.; Coombs, M.; Dehn, J.; Realmuto, V. J.

2006-12-01

380

Thermodynamics and Spontaneity  

NASA Astrophysics Data System (ADS)

Despite the importance of thermodynamics as the foundation of chemistry, most students emerge from introductory courses with only a dim understanding of this subject. Generally students recognize that the information is significant, yet do not assimilate it into later studies, especially in applied fields such as biology and biochemistry. A clear sense of the problem is reflected in a number of other contributions to this Journal (e.g., 1 - 6). Most (1 - 4, 6) recommend increased rigor in derivation of equations. This may appeal to students in advanced courses in chemical thermodynamics, but not to most. A few other suggestions are to introduce the subject earlier in general chemistry courses (2) or to provide innovative ways to visualize reaction changes (3). I suggest that the problem lies at another level entirely: the meanings of the terms are not clear. Recently, MacNeal (7) introduced the concept of mathsemantics, the joining of mathematics with a deep understanding of the sense (semantics) in which it operates. For example, the author argues that not only can we add apples and oranges (yielding total fruit), but that anything less than such a synthesis is trivial. Mathematics is hard, not because of the actual mathematical part of the problem but because of the semantics. As discussed thoroughly by Weinburg (8), the very names we affix to ideas dominate how we think about them. A similar reorientation would benefit chemical education. By way of example, the word "spontaneous" is widely used in thermodynamics, presumably because the word is familiar and assists understanding of this subject. In the following, I will provide evidence that this word has contributed more to the obfuscation of chemical ideas than it has helped elucidate them. Literature Cited 1. Redlich, O. J. Chem. Educ. 1975, 52, 374 - 376. 2. Bergquist, W.; Heikkinen, H. J. Chem. Educ. 1990, 67, 1000 - 1003. 3. Macomber, R. S. J. Chem. Educ. 1994, 71, 311 - 312. 4. Sanchez, K. S.; Vergenz, R. A. J. Chem. Educ. 1994, 71, 562 - 566. 5. Feiner, A. S.; McEvoy, A. J. J. Chem. Educ. 1994, 71, 493 - 494. 6. Gerhartl, F. J. J. Chem. Educ. 1994, 71, 539 - 548. 7. MacNeal, E. Mathsemantics. Making Numbers Make Sense; Viking: New York, 1994. 8. Weinberg, G. M. An Introduction to General Systems Thinking; Wiley-Interscience: 1985.

Ochs, Raymond S.

1996-10-01

381

Analysis of the mechanisms for impaired high-temperature high-speed performance of 1.3-?m InGaAsP lasers  

NASA Astrophysics Data System (ADS)

In this paper, the static and dynamic performance of multi quantum-well (MQW) 1.3 micrometer InGaAsP Fabry Perot lasers is assessed experimentally and theoretically to identify the mechanisms responsible for impaired high speed performance at elevated temperature. Initially, threshold currents and spontaneous emission spectra are characterized for a range of temperatures from room temperature to 85 degrees Celsius to indicate a significant increase in non-radiative current contributions. Preliminary estimates are made for the contributions of leakage and Auger recombination rates, found from the dependence of integrated spontaneous emission with carrier density. Drift-diffusion modeling is found to accurately predict the trend of threshold currents over temperature. Using gain modeling good agreement is found between the measured and predicted integrated spontaneous emission intensity. Gain measurements at 85 degrees Celsius indicate a reduction in RIN frequency to 63% of the 25 degree Celsius value which matches well with experimental small signal performance.

Massara, Aeneas B.; Williams, Kevin A.; Yong, Jennifer L.; Onischenko, Alexander I.; Rorison, Judy M.; Penty, Richard V.; White, Ian H.; Galbraith, Andrew; Crump, Paul; Silver, Mark

2000-07-01

382

Geotech Smart24 data acquisition system input terminated noise seismic response adjusted test : StreckeisenSTS2-low and high gain, Guralp CMG3T and Geotech GS13 seismometers.  

SciTech Connect

Sandia National Laboratories has tested, evaluated and reported on the Geotech Smart24 data acquisition system with active Fortezza crypto card data signing and authentication in SAND2008-. One test, Input Terminated Noise, allows us to characterize the self-noise of the Smart24 system. By computing the power spectral density (PSD) of the input terminated noise time series data set and correcting for the instrument response of different seismometers, the resulting spectrum can be compared to the USGS new low noise model (NLNM) of Peterson (1996), and determine the ability of the matched system of seismometer and Smart24 to be quiet enough for any general deployment location. Four seismometer models were evaluated: the Streckeisen STS2-Low and High Gain, Guralp CMG3T and Geotech GS13 models. Each has a unique pass-band as defined by the frequency band of the instrument corrected noise spectrum that falls below the new low-noise model.

Rembold, Randy Kai; Hart, Darren M.; Harris, James Mark

2008-08-01

383

Menstruation-related spontaneous pneumothorax and diaphragmatic endometriosis.  

PubMed

Menstruation-related spontaneous pneumothorax (MSP), also termed catamenial pneumothorax, is a syndrome of spontaneous pneumothorax during menstruation due to endometriotic lesions in the diaphragm and thoracic cavity. Previously MSP was considered rare, and to cause only 3-6% of all spontaneous pneumothoraces in otherwise healthy women. Current data suggest that the incidence is substantially higher and MSP might be the reason for spontaneous pneumothoraces in up to 25-33% of all cases in women of reproductive age. The typical characteristics are a high recurrence rate and diaphragmatic spread of endometriotic lesions. We report six patients who had been diagnosed to have diaphragmatic endometriosis and four of them had developed MSP. Optimal management requires flexible collaboration between thoracic surgeons and gynecologists. Although treatment is primarily surgical, long-lasting and successful management requires that amenorrhea is induced with hormonal therapy, either by continuous contraceptives, progestins, the levonorgestrel-releasing intrauterine device or GnRH-agonists. PMID:20524838

Härkki, Päivi; Jokinen, Janne J; Salo, Jarmo A; Sihvo, Eero

2010-09-01

384

Spontaneous regression of an anterior skull base mass.  

PubMed

Spontaneous regression of an intracranial mass is rare. We report a 77-year-old man with spontaneous regression of an anterior skull base mass suspected to be an inflammatory pseudotumor. The patient attended our outpatient department approximately once per month for a regular check-up following a brain stem infarction. A small mass was detected at the anterior skull base by MRI. The mass gradually grew to about 3 cm over a period of 5 years and then remained stable for 3 years. Thereafter, the mass showed spontaneous regression 8 years after it was first visible on MRI. 'Inflammatory pseudotumor' is a broad category and the natural history of these lesions is highly variable. Although the definition does include some types of malignant lesion, most masses are benign lesions that can regress spontaneously, as in our patient. A 'wait-and-see' policy is appropriate for such patients. PMID:20356749

Katoh, Masahito; Imamura, Hiroyuki; Yoshino, Masami; Aoki, Takeshi; Abumiya, Takeo; Aida, Toshimitsu

2010-06-01

385

Complex vacuum fluctuation as a chaotic “limit” set of any Kleinian group transformation and the mass spectrum of high energy particle physics via spontaneous self-organization  

Microsoft Academic Search

First we give an introduction to the E(?) quantum space-time theory from the point of view of nonlinear dynamics, complexity, string and KAM theory. Subsequently we give without proof several theorems that we consider to be fundamental to the foundation of any general theory for high energy particles interaction. The final picture seems to be a synthesis between compactified Kleinian

M. S. El Naschie

2003-01-01

386

Achieving yield gains in wheat.  

PubMed

Wheat provides 20% of calories and protein consumed by humans. Recent genetic gains are <1% per annum (p.a.), insufficient to meet future demand. The Wheat Yield Consortium brings expertise in photosynthesis, crop adaptation and genetics to a common breeding platform. Theory suggest radiation use efficiency (RUE) of wheat could be increased ~50%; strategies include modifying specificity, catalytic rate and regulation of Rubisco, up-regulating Calvin cycle enzymes, introducing chloroplast CO(2) concentrating mechanisms, optimizing light and N distribution of canopies while minimizing photoinhibition, and increasing spike photosynthesis. Maximum yield expression will also require dynamic optimization of source: sink so that dry matter partitioning to reproductive structures is not at the cost of the roots, stems and leaves needed to maintain physiological and structural integrity. Crop development should favour spike fertility to maximize harvest index so phenology must be tailored to different photoperiods, and sensitivity to unpredictable weather must be modulated to reduce conservative responses that reduce harvest index. Strategic crossing of complementary physiological traits will be augmented with wide crossing, while genome-wide selection and high throughput phenotyping and genotyping will increase efficiency of progeny screening. To ensure investment in breeding achieves agronomic impact, sustainable crop management must also be promoted through crop improvement networks. PMID:22860982

Reynolds, Matthew; Foulkes, John; Furbank, Robert; Griffiths, Simon; King, Julie; Murchie, Erik; Parry, Martin; Slafer, Gustavo

2012-10-01

387

Gain of a single gas electron multiplier  

NASA Astrophysics Data System (ADS)

Gas Electron Multiplier (GEM) is a gaseous detector used in particle detection and is known for its high rate capability. Ever since its invention in 1997, GEM was applied in many areas and recently has been proposed to be installed in the CMS high ? regions for upgrade at LHC, CERN. A complete understanding of the working and gain behaviour does not exist. GEM gain is influenced by charging up and this has been variedly interpreted in literature lacking consensus. I have attempted in this work through simulations and measurements to achieve a better understanding of single GEM gain and how it is affected by various factors. Specific experimental methods which evolved with subsequent measurements were employed to systematically study the charging up effect. Information from simulations was applied to characterize measurements thereby enabling the development of a model for charging up. Conductivity mechanism of the dielectric used in GEM was analyzed and the resistivity measured. Gain free of charging up effects was measured and this is appropriate for comparison with simulations.

Nemallapudi, Mythra Varun

388

Optical antenna enhanced spontaneous emission  

PubMed Central

Atoms and molecules are too small to act as efficient antennas for their own emission wavelengths. By providing an external optical antenna, the balance can be shifted; spontaneous emission could become faster than stimulated emission, which is handicapped by practically achievable pump intensities. In our experiments, InGaAsP nanorods emitting at ?200 THz optical frequency show a spontaneous emission intensity enhancement of 35× corresponding to a spontaneous emission rate speedup ?115×, for antenna gap spacing, d = 40 nm. Classical antenna theory predicts ?2,500× spontaneous emission speedup at d ? 10 nm, proportional to 1/d2. Unfortunately, at d < 10 nm, antenna efficiency drops below 50%, owing to optical spreading resistance, exacerbated by the anomalous skin effect (electron surface collisions). Quantum dipole oscillations in the emitter excited state produce an optical ac equivalent circuit current, Io = q?|xo|/d, feeding the antenna-enhanced spontaneous emission, where q|xo| is the dipole matrix element. Despite the quantum-mechanical origin of the drive current, antenna theory makes no reference to the Purcell effect nor to local density of states models. Moreover, plasmonic effects are minor at 200 THz, producing only a small shift of antenna resonance frequency. PMID:25624503

Eggleston, Michael S.; Messer, Kevin; Zhang, Liming; Yablonovitch, Eli; Wu, Ming C.

2015-01-01

389

Modal Analysis and Gain Estimation  

NASA Technical Reports Server (NTRS)

Interactive program yields eigenvectors, eigenvalues, and gains for feedback-control systems. Interactive Modal Analysis and Gain Estimation System (IMAGES) provides eigensystem synthesis capability to control-system engineer. IMAGES modular and flexible. Capable of both modal and spectral synthesis of multi-input control systems. IMAGES user-oriented, interactive program that frees engineer to concentrate on eigensystem synthesis. Engineer provided with scratch-pad capability that speeds control-system design.

Jones, R. L.

1986-01-01

390

The Lloyd L. Gaines Collection  

NSDL National Science Digital Library

Born in 1911, Lloyd Lionel Gaines was one of eleven children. Gaines excelled in his studies and applied to the University of Missouri School of Law in 1936. He was denied admission solely on the grounds that Missouri's state constitution called for "separate education of the races." Gaines did not back down from this injustice, and he sought legal assistance from the NAACP. In 1938, Gaines won his case before the United States Supreme Court, but tragically Gaines disappeared at age 28 in Chicago and was never seen or heard from again. This engaging collection from the University of Missouri Law Library brings together documents related to Gaines's life, including photographs, family correspondence, materials related to his Supreme Court case, and related secondary materials. Visitors to the site can perform a simple search across all the materials, or dig in deeper by perform a citation search. Legal scholars will find the Case Materials area particularly engaging, as it includes links to the trial briefs, respondents' statements, and so on.

391

Spontaneous closure of macular hole.  

PubMed

We report a case of spontaneous closure of stage-II macular hole. A 66 years old lady presented with decreased vision in her left eye for the last 3 months. Her vision was 6/18 in right eye and finger counting at 3 feet in left eye. Optical coherence tomography showed stage-II macular hole in left eye. There was attachment of vitreous at the edge of the hole. Minimal hole diameter was 119 ?. Macular hole surgery was planned. During follow-up, hole started closing spontaneously. Nine months later, the hole closed and posterior hyaloid membrane separated from the macula. Visual acuity improved to 6/24. The purpose of this case report is to show that stage-II macular hole may close spontaneously with relief of vitreomacular traction. PMID:24906260

Jamil, Ahmad Zeeshan; Aqil, Amash; Khaliq, Javed; Mirza, Khurram Azam

2014-05-01

392

Gain measurements of the Ca-Xe charge exchange system. [for UV lasers  

NASA Technical Reports Server (NTRS)

Charge-exchange-pumped Ca(+) was studied for possible positive laser gain at 370.6 and 315.9 nm using an Xe MPD arc as the Xe(+) source. The present paper describes the MPD arc, the calcium injection system, the diagnostics for gain, and spontaneous emission measurements and results. No positive gain measurements were observed. A small Xe-Ca charge exchange cross section compared to He-metal laser systems charge exchange cross sections is the most probable reason why the result was negative.

Michels, C. J.; Chubb, D. L.

1978-01-01

393

Factors affecting feedlot gains of Hereford bulls  

E-print Network

correlation coefficients between 140-day gain, age, gain from weaning to start, initial condition and initial weight 19 5. General outline for nested analysis 21 6. Correlation coefficients between various periods of 140-day gain test... for initial condition groups 2S 30 Mean gain per period for gain from weaning to start groups . 32 INTRODUCTIOH Differences in the ability of individuals to gain weight have long bean recognised; however, gain records have not been recommended ss a...

Thomas, Richard Carroll

2012-06-07

394

Are Consonant Intervals Music to Their Ears?: Spontaneous Acoustic Preferences in a Nonhuman Primate  

ERIC Educational Resources Information Center

Humans find some sounds more pleasing than others; such preferences may underlie our enjoyment of music. To gain insight into the evolutionary origins of these preferences, we explored whether they are present in other animals. We designed a novel method to measure the spontaneous sound preferences of cotton-top tamarins, a species that has been…

McDermott, Josh; Hauser, Marc

2004-01-01

395

Multiple genetic switches spontaneously modulating bacterial mutability  

PubMed Central

Background All life forms need both high genetic stability to survive as species and a degree of mutability to evolve for adaptation, but little is known about how the organisms balance the two seemingly conflicting aspects of life: genetic stability and mutability. The DNA mismatch repair (MMR) system is essential for maintaining genetic stability and defects in MMR lead to high mutability. Evolution is driven by genetic novelty, such as point mutation and lateral gene transfer, both of which require genetic mutability. However, normally a functional MMR system would strongly inhibit such genomic changes. Our previous work indicated that MMR gene allele conversion between functional and non-functional states through copy number changes of small tandem repeats could occur spontaneously via slipped-strand mis-pairing during DNA replication and therefore may play a role of genetic switches to modulate the bacterial mutability at the population level. The open question was: when the conversion from functional to defective MMR is prohibited, will bacteria still be able to evolve by accepting laterally transferred DNA or accumulating mutations? Results To prohibit allele conversion, we "locked" the MMR genes through nucleotide replacements. We then scored changes in bacterial mutability and found that Salmonella strains with MMR locked at the functional state had significantly decreased mutability. To determine the generalizability of this kind of mutability 'switching' among a wider range of bacteria, we examined the distribution of tandem repeats within MMR genes in over 100 bacterial species and found that multiple genetic switches might exist in these bacteria and may spontaneously modulate bacterial mutability during evolution. Conclusions MMR allele conversion through repeats-mediated slipped-strand mis-pairing may function as a spontaneous mechanism to switch between high genetic stability and mutability during bacterial evolution. PMID:20836863

2010-01-01

396

Galileo mission planning for Low Gain Antenna based operations  

Microsoft Academic Search

The Galileo mission operations concept is undergoing substantial redesign, necessitated by the deployment failure of the High Gain Antenna, while the spacecraft is on its way to Jupiter. The new design applies state-of-the-art technology and processes to increase the telemetry rate available through the Low Gain Antenna and to increase the information density of the telemetry. This paper describes the

R. Gershman; K. L. Buxbaum; J. M. Ludwinski; B. G. Paczkowski

1994-01-01

397

GALILEO MISSION PLANNING FOR LOW GAIN ANTENNA BASED OPERATIONS  

Microsoft Academic Search

The Galileo mission operations concept is undergo- ing substantial redesign, necessitated by the deploy- ment failure of the High Gain Antenna, while the spacecraft is on its way to Jupiter. The new design applies state-of-the-art technology and processes to increase the telemetry rate available through the Low Gain Antenna and to increase the information density of the telemetry. This paper

R. Gershman; K. L. Buxbaum; B. G. Paczkowski

398

Spontaneous reorientation of bimetal multilayer nanowires  

SciTech Connect

Multilayered structures are proposed to extend the size range at which metal nanowires can transform spontaneously from one orientation to another due to the interfacial stress. The principle is demonstrated on gold-palladium (Au-Pd) multilayer nanowires by using the molecular dynamics (MD) method and two distinctly different mechanisms are identified for the reorientation which take place mainly via slipping and twinning at low temperature and by amorphization and recrystallization at high temperature. Our results show that the time response of devices fabricated with the nanostructures is consequently affected.

Ma Fei; Ma Shengli; Xu Kewei; Chu, Paul K. [State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049 Shaanxi (China) and Department of Physics and Materials Science, City University of Hong Kong, Kowloon, Hong Kong (China); State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049 Shaanxi (China); Department of Physics and Materials Science, City University of Hong Kong, Kowloon, Hong Kong (China)

2007-12-17

399

Gain scaling for multirate filter banks  

SciTech Connect

Eliminating two trivial degrees of freedom corresponding to the lowpass DC response and the highpass Nyquist response in a two-channel multirate filter bank seems simple enough. Nonetheless, the ISO/IEC JPEG 2000 image coding standard manages to make this mundane task look totally mysterious. We reveal the true meaning behind JPEG 2000's arcane specifications for filter bank normalization and point out how the seemingly trivial matter of gain scaling leads to highly nontrivial issues concerning uniqueness of lifting factorizations.

Brislawn, Christopher M [Los Alamos National Laboratory

2009-01-01

400

A rare spontaneous enterocutaneous fistula  

PubMed Central

A 70-year-old woman presented with a short history of a spontaneous enterocutaneos fistula in the left inguinal region. A laparotomy revealed a fistulizing Richter's hernia. The fistulizing small bowel segment was resected and the femoral hernia repaired from below. Although rare, a complicating Richter's hernia should be considered in the differential diagnosis of a groin fistula. PMID:25391523

Weledji, Elroy P.; Puepi, Marlene A.; Chichom, Alain M.

2014-01-01

401

Spontaneous Mutation Accumulation Studies in  

E-print Network

Spontaneous Mutation Accumulation Studies in Evolutionary Genetics Daniel L. Halligan and Peter D of mutation effects, dominance, epistasis, genotype-environment interaction, mutation rate Abstract Mutation accumulation (MA) experiments, in which mutations are allowed to drift to fixation in inbred lines, have been

Keightley, Peter

402

Silicosis with bilateral spontaneous pneumothorax  

PubMed Central

Presentation with simultaneous bilateral pneumothorax is uncommon and usually in the context of secondary spontaneous pneumothorax. The association of pneumothorax and silicosis is infrequent and most cases are unilateral. Bilateral pneumothorax in silicosis is very rare with just a few reports in medical literature. PMID:20931041

Fotedar, Sanjay; Chaudhary, Dhruva; Singhla, Vikas; Narang, Rajat

2010-01-01

403

Welfare Gains from Financial Liberalization  

PubMed Central

Financial liberalization has been a controversial issue, as empirical evidence for growth enhancing effects is mixed. Here, we find sizable welfare gains from liberalization (cost to repression), though the gain in economic growth is ambiguous. We take the view that financial liberalization is a government policy that alters the path of financial deepening, while financial deepening is endogenously chosen by agents given a policy and occurs in transition towards a distant steady state. This history-dependent view necessitates the use of simulation analysis based on a growth model. Our application is a specific episode: Thailand from 1976 to 1996. PMID:20806055

Townsend, Robert M.; Ueda, Kenichi

2010-01-01

404

Ongoing Spontaneous Activity Controls Access to Consciousness  

E-print Network

Ongoing Spontaneous Activity Controls Access to Consciousness: A Neuronal Model for Inattentional of endogenous states of consciousness, and particularly the blocking of access to consciousness that occurs of consciousness. Citation: Dehaene S, Changeux JP (2005) Ongoing spontaneous activity controls access

Paris-Sud XI, Université de

405

Perspective methods for the generation of COIL gain medium  

NASA Astrophysics Data System (ADS)

An ejector nozzle bank powered by centrifugal bubbling SOG is considered like highly efficient gain generating system for COIL. A high potential recovered pressure ~100 torr of the gain medium flow with a small signal gain higher than 1% cm -1 and low oxygen plenum pressure has been demonstrated. A centrifugal bubbling SOG is an efficient source of oxygen at high pressure with high depletion of the BHP in the single burn dawn. A high 0 II(1?) yield and chlorine utilization higher than 90% have been obtained at chlorine gas loading up to 6 mmole/s per 1 cm2 of the bubbler surface. The ejector COIL powered by centrifugal bubbling SOG demonstrated ~25% of chemical efficiency with specific power 6 kJ per 1 litre of the BHP in the single burn dawn. The combination of centrifugal bubble SOG with ejector nozzle bank can be considered as a promising gain medium flow generation system for COIL.

Zagidullin, Marsel V.; Nikolaev, Valery D.; Svistun, Michael I.; Khvatov, Nikolay A.

2007-04-01

406

Spontaneity of Communication in Individuals with Autism  

Microsoft Academic Search

This article provides an examination of issues related to spontaneity of communication in children with autism. Deficits relating\\u000a to spontaneity or initiation are frequently reported in individuals with autism, particularly in relation to communication\\u000a and social behavior. Nevertheless, spontaneity is not necessarily clearly conceptualized or measured. Several approaches to\\u000a conceptualization of communicative spontaneity are examined with a particular focus on

Hsu-Min Chiang; Mark Carter

2008-01-01

407

Spontaneous order: Michael Polanyi and Friedrich Hayek  

Microsoft Academic Search

This paper compares Hayek and Polanyi on spontaneous social order. Although Hayek is widely believed to have first both coined the name and explicated the idea of ‘spontaneous order’, it is in fact Michael Polanyi who did so. Numerous differences emerge between the two thinkers. The characterisation of spontaneous order in Hayek, for example, involves different types of freedom to

Struan Jacobs

2000-01-01

408

Chapter 8. Spontaneous Processes and Thermodynamic Equilibrium  

E-print Network

of Thermodynamics · The efficiency: the ratio of work accomplished by the engine in a cycle to the heat invested compressing spontaneously, but the event is so improbable, it is not seen. The directionality of spontaneous by thermodynamics. #12;Example 8.1 · Calculate the probability of a spontaneous compression of 1.00 mol of gas by 0

Ihee, Hyotcherl

409

Spontaneous Prediction Error Generation in Schizophrenia  

E-print Network

Spontaneous Prediction Error Generation in Schizophrenia Yuichi Yamashita¤a , Jun Tani. In this study, we show that neural networks containing schizophrenia-like deficits can spontaneously generate: Yamashita Y, Tani J (2012) Spontaneous Prediction Error Generation in Schizophrenia. PLoS ONE 7(5): e37843

Tani, Jun

410

The Gains from Vertical Scaling  

ERIC Educational Resources Information Center

It is often assumed that a vertical scale is necessary when value-added models depend upon the gain scores of students across two or more points in time. This article examines the conditions under which the scale transformations associated with the vertical scaling process would be expected to have a significant impact on normative interpretations…

Briggs, Derek C.; Domingue, Ben

2013-01-01

411

PATTERNS FOR GAINING DIFFERENT PERSPECTIVES  

E-print Network

PATTERNS FOR GAINING DIFFERENT PERSPECTIVES A part of the Pedagogical Patterns Project pattern into play at just the right time to enhance student learning. The Pedagogical Patterns Project (www was written by Astrid Fricke and Markus Voelter [AF] and revised by Jutta Eckstein. Communication always takes

Wallingford, Eugene

412

High Resolution LC-MSn Fragmentation Pattern of Palytoxin as Template to Gain New Insights into Ovatoxin-a Structure. The Key Role of Calcium in MS Behavior of Palytoxins  

NASA Astrophysics Data System (ADS)

Palytoxin is a potent marine toxin and one of the most complex natural compounds ever described. A number of compounds identified as palytoxin congeners (e.g., ovatoxins, mascarenotoxins, ostreocins, etc.) have not been yet structurally elucidated due to lack of pure material in quantities sufficient to an NMR-based structural investigation. In this study, the complex fragmentation pattern of palytoxin in its positive high resolution liquid chromatography tandem mass spectra (HR LC-MSn) was interpreted. Under the used conditions, the molecule underwent fragmentation at many sites of its backbone, and a large number of diagnostic fragment ions were identified. The natural product itself was used with no need for derivatization. Interestingly, most of the fragments contained calcium in their elemental formula. Evidence for palytoxin tendency to form adduct ions with calcium and other divalent cations in its mass spectra was obtained. Fragmentation pattern of palytoxin was used as template to gain detailed structural information on ovatoxin-a, the main toxin produced by Ostreopsis ovata, (observe correct font) a benthic dinoflagellate that currently represents the major harmful algal bloom threat in the Mediterranean area. Either the regions or the specific sites where ovatoxin-a and palytoxin structurally differ have been identified.

Ciminiello, Patrizia; Dell'Aversano, Carmela; Dello Iacovo, Emma; Fattorusso, Ernesto; Forino, Martino; Grauso, Laura; Tartaglione, Luciana

2012-05-01

413

Healthy Weight Gain for Teens: A Guide for Parents  

MedlinePLUS

... they are growing taller, exercising a lot with sports, or they might simply have a high metabolism ( ... gain but remember to have discussions about school, sports, current events, and feelings with your teen. Written ...

414

Laser Cooling without Spontaneous Emission  

NASA Astrophysics Data System (ADS)

This Letter reports the demonstration of laser cooling without spontaneous emission, and thereby addresses a significant controversy. It works by restricting the atom-light interaction to a time short compared to a cycle of absorption followed by natural decay. It is achieved by using the bichromatic force on an atomic transition with a relatively long excited state lifetime and a relatively short cooling time so that spontaneous emission effects are minimized. The observed width of the one-dimensional velocity distribution is reduced by ×2 thereby reducing the "temperature" by ×4 . Moreover, our results comprise a compression in phase space because the spatial expansion of the atomic sample is limited. This accomplishment is of interest to direct laser cooling of molecules or in experiments where working space or time is limited.

Corder, Christopher; Arnold, Brian; Metcalf, Harold

2015-01-01

415

Spontaneous Photon Emission in Cavities  

E-print Network

We investigate spontaneous photon emission processes of two-level atoms in parabolic and ellipsoidal cavities thereby taking into account the full multimode scenario. In particular, we calculate the excitation probabilities of the atoms and the energy density of the resulting few-photon electromagnetic radiation field by using semiclassical methods for the description of the multimode scenario. Based on this approach photon path representations are developed for relevant transition probability amplitudes which are valid in the optical frequency regime where the dipole and the rotating-wave approximations apply. Comparisons with numerical results demonstrate the quality of these semiclassical results even in cases in which the wave length of a spontaneously emitted photon becomes comparable or even larger than characteristic length scales of the cavity. This is the dynamical regime in which diffraction effects become important so that geometric optical considerations are typically not applicable.

Gernot Alber; Nils Trautmann

2014-12-04

416

Speeding up spontaneous disease extinction  

NASA Astrophysics Data System (ADS)

The dynamics of epidemic in a susceptible population is affected both by the random character of interactions between the individuals and by environmental variations. As a consequence, the sizes of the population groups (infected, susceptible, etc.) fluctuate in the course of evolution of the epidemic. In a small community a rare large fluctuation in the number of infected can result in extinction of the disease. We suggest a novel paradigm of controlling the epidemic, where the control field, such as vaccination, is designed to maximize the rate of spontaneous disease extinction. We show that, for a limited-scope vaccination, the optimal vaccination protocol and its impact on the epidemics have universal features: (i) the vaccine must be applied in pulses, (ii) the spontaneous disease extinction is synchronized with the vaccination. We trace this universality to general properties of the response of large fluctuations to external perturbations.

Khasin, Michael

2012-02-01

417

Spontaneous chirality in simple systems  

PubMed

Two simple examples of spontaneous chiral symmetry breaking are presented. The first is close-packed cylindrically confined spheres. As the cylinder diameter is varied, one obtains a variety of chiral phases. The second example involves unconfined dipolar particles with an isotropic attraction, which also exhibits chiral ground states. We speculate that a dilute magnetorheological fluid film, with the addition of smaller particles to provide an attractive entropic interaction, will exhibit a chiral columnar ground state. PMID:11030973

Pickett; Gross; Okuyama

2000-10-23

418

Spontaneous esophageal-pleural fistula.  

PubMed

Spontaneous esophageal-pleural fistula (EPF) is a rare entity. We describe a case in a middle-aged female who presented with severe retrosternal chest pain and shortness of breadth. Chest computed tomography showed right EPF and hydropneumothorax. She was managed conservatively keeping the chest tube drainage and performing feeding jejunostomy. A brief review of the imaging finding and management of EPF is discussed. PMID:22084548

Vyas, Sameer; Prakash, Mahesh; Kaman, Lileshwar; Bhardwaj, Nidhi; Khandelwal, Niranjan

2011-10-01

419

Spontaneous esophageal-pleural fistula  

PubMed Central

Spontaneous esophageal-pleural fistula (EPF) is a rare entity. We describe a case in a middle-aged female who presented with severe retrosternal chest pain and shortness of breadth. Chest computed tomography showed right EPF and hydropneumothorax. She was managed conservatively keeping the chest tube drainage and performing feeding jejunostomy. A brief review of the imaging finding and management of EPF is discussed. PMID:22084548

Vyas, Sameer; Prakash, Mahesh; Kaman, Lileshwar; Bhardwaj, Nidhi; Khandelwal, Niranjan

2011-01-01

420

Give spontaneity and self-discovery a chance in ASD: spontaneous peripheral limb variability as a proxy to evoke centrally driven intentional acts  

PubMed Central

Autism can be conceived as an adaptive biological response to an early unexpected developmental change. Under such conceptualization one could think of emerging biological compensatory mechanisms with unique manifestations in each individual. Within a large group of affected people this would result in a highly heterogeneous spectral disorder where it would be difficult to tap into the hidden potentials of any given individual. A pressing question is how to treat the disorder while harnessing the capabilities and predispositions that the individual has already developed. It would indeed be ideal to use such strengths to accelerate the learning of self-sufficiency and independence, important as the person transitions into adulthood. In this report, we introduce a new concept for therapeutic interventions and basic research in autism. We use visuo-spatial and auditory stimuli to help augment the physical reality of the child and sensory-substitute corrupted kinesthetic information quantified in his/her movement patterns to help the person develop volitional control over the hand motions. We develop a co-adaptive child-computer interface that closes the sensory-motor feedback loops by alerting the child of a cause-effect relationship between the statistics of his/her real-time hand movement patterns and those of external media states. By co-adapting the statistics of the media states and those of the child's real-time hand movements, we found that without any food/token reward the children naturally remained engaged in the task. Even in the absence of practice, the learning gains were retained, transferred and improved 2–4 weeks later. This new concept demonstrates that individuals with autism do have spontaneous sensory-motor adaptive capabilities. When led to their self-discovery, these patterns of spontaneous behavioral variability (SBV) morph into more predictive and reliable intentional actions. These can unlock and enhance exploratory behavior and autonomy in the individual with autism spectrum disorders (ASD). PMID:23898243

Torres, Elizabeth B.; Yanovich, Polina; Metaxas, Dimitris N.

2013-01-01

421

Noise-enhanced spontaneous chaos in semiconductor superlattices at room temperature  

NASA Astrophysics Data System (ADS)

Physical systems exhibiting fast spontaneous chaotic oscillations are used to generate high-quality true random sequences in random number generators. The concept of using fast practical entropy sources to produce true random sequences is crucial to make storage and transfer of data more secure at very high speeds. While the first high-speed devices were chaotic semiconductor lasers, the discovery of spontaneous chaos in semiconductor superlattices at room temperature provides a valuable nanotechnology alternative. Spontaneous chaos was observed in 1996 experiments at temperatures below liquid nitrogen. Here we show spontaneous chaos at room temperature appears in idealized superlattices for voltage ranges where sharp transitions between different oscillation modes occur. Internal and external noises broaden these voltage ranges and enhance the sensitivity to initial conditions in the superlattice snail-shaped chaotic attractor thereby rendering spontaneous chaos more robust.

Alvaro, M.; Carretero, M.; Bonilla, L. L.

2014-08-01

422

Randoms and TOF gain revisited.  

PubMed

Time-of-flight (TOF) positron emission tomography (PET) typically reduces the variance in the images by a factor that is proportional to the size of the object to be scanned, and inversely proportional to the time resolution of the PET scanner. Attempts to better characterize this relationship and understand its limits have been published, showing that such gain also increases with random fraction. In this paper, new experimental and simulated data are analyzed and old results are incorporated in the study. The proportionality of TOF gain with time resolution is confirmed, the proportionality constant is measured, the effect of the randoms is validated, and the limit of the model for small objects is investigated. PMID:25615713

Eriksson, Lars; Conti, Maurizio

2015-02-21

423

Randoms and TOF gain revisited  

NASA Astrophysics Data System (ADS)

Time-of-flight (TOF) positron emission tomography (PET) typically reduces the variance in the images by a factor that is proportional to the size of the object to be scanned, and inversely proportional to the time resolution of the PET scanner. Attempts to better characterize this relationship and understand its limits have been published, showing that such gain also increases with random fraction. In this paper, new experimental and simulated data are analyzed and old results are incorporated in the study. The proportionality of TOF gain with time resolution is confirmed, the proportionality constant is measured, the effect of the randoms is validated, and the limit of the model for small objects is investigated.

Eriksson, Lars; Conti, Maurizio

2015-02-01

424

Comparing vocal parameters in spontaneous and posed child-directed speech  

Microsoft Academic Search

Research on the facial expression of emotion distinguishes between correlates of posed vs. spontaneous emotion expression. Similar research in the vocal domain is lacking. In this study, we compare changes in a range of vocal parameters between posed vs. spontaneous adult-directed (AD) and child-directed (CD) speech. CDS is a highly affectively charged speech register which lends itself well to the

F. Schaeffler; V. Kempe; S. Biersack

425

Amplified spontaneous emission over the XeF(D+X) transition in solid Kr H. Kunttu, W. G. Lawrence, and V. A. Apkariar?)  

E-print Network

Amplified spontaneous emission over the XeF(D+X) transition in solid Kr H. Kunttu, W. G. Lawrence of gain on pump intensity and low divergence of the amplified beam are taken as evidence for self to amplified sponta- neous emission (ASE) is observed and used to characterize the gain in the medium.2

Apkarian, V. Ara

426

Controlling spontaneous emission with plasmonic optical patch antennas  

E-print Network

We experimentally demonstrate the control of the spontaneous emission rate and the radiation pattern of colloidal quantum dots deterministically positioned in a plasmonic patch antenna. The antenna consists of a thin gold microdisk 30 nm above a thick gold layer. The emitters are shown to radiate through the entire patch antenna in a highly directional and vertical radiation pattern. Strong acceleration of spontaneous emission is observed, depending of the antenna size. Considering the double dipole structure of the emitters, this corresponds to a Purcell factor up to 80 for dipoles perpendicular to the disk.

C. Belacel; B. Habert; F. Bigourdan; F. Marquier; J. -P. Hugonin; S. Michaelis de Vasconcellos; X. Lafosse; L. Coolen; C. Schwob; C. Javaux; B. Dubertret; J. -J. Greffet; P. Senellart; A. Maitre

2012-09-28

427

Spontaneous ad hoc mobile cloud computing network.  

PubMed

Cloud computing helps users and companies to share computing resources instead of having local servers or personal devices to handle the applications. Smart devices are becoming one of the main information processing devices. Their computing features are reaching levels that let them create a mobile cloud computing network. But sometimes they are not able to create it and collaborate actively in the cloud because it is difficult for them to build easily a spontaneous network and configure its parameters. For this reason, in this paper, we are going to present the design and deployment of a spontaneous ad hoc mobile cloud computing network. In order to perform it, we have developed a trusted algorithm that is able to manage the activity of the nodes when they join and leave the network. The paper shows the network procedures and classes that have been designed. Our simulation results using Castalia show that our proposal presents a good efficiency and network performance even by using high number of nodes. PMID:25202715

Lacuesta, Raquel; Lloret, Jaime; Sendra, Sandra; Peñalver, Lourdes

2014-01-01

428

Spontaneous Natural Fibrillogenesis on Charged Surfaces  

NASA Astrophysics Data System (ADS)

In the developing field of tissue engineering, conditions must resemble the natural tissue environment. The interaction between the cells and their surrounding extracellular matrix (ECM) has been shown to be vital for cell proliferation and adhesion. One major obstacle to study normal ECM formation has been that, even though some of the proteins, such as collagen, self-assemble spontaneously, others, such as fibronectin and elastin, do not. They have been observed in their natural fibrillar state only on cell membranes. Hence the structures of the ECM have not been previously reproduced in vitro. We have recently demonstrated that spontaneous fibrillogenesis of fibronectin (Fn) can be induced on highly charged surfaces, such as sulfonated polystyrene (SPS). Furthermore, once the protein formed fibrils, they self-assembled into a large periodic network. We also demonstrated that a similar lattice was produced naturally by cardiac fibroblast cells when deposited directly onto the same polyelectrolyte coated surfaces. ECM production and organization were shown to be significantly affected by the presence of external compounds such as iron, glucose¡­ Since we can vary each of the components individually, we can the study their effect on the cell morphology and expression. Hence through these studies we can develop a more fundamental understanding of the factors responsible for some pathologies, such as diabetes.

Pernodet, N.; Simper, M.; Frenkel, R.; Collazo, L.; Ge, S.; Rafailovich, M.

2003-03-01

429

Spontaneous Ad Hoc Mobile Cloud Computing Network  

PubMed Central

Cloud computing helps users and companies to share computing resources instead of having local servers or personal devices to handle the applications. Smart devices are becoming one of the main information processing devices. Their computing features are reaching levels that let them create a mobile cloud computing network. But sometimes they are not able to create it and collaborate actively in the cloud because it is difficult for them to build easily a spontaneous network and configure its parameters. For this reason, in this paper, we are going to present the design and deployment of a spontaneous ad hoc mobile cloud computing network. In order to perform it, we have developed a trusted algorithm that is able to manage the activity of the nodes when they join and leave the network. The paper shows the network procedures and classes that have been designed. Our simulation results using Castalia show that our proposal presents a good efficiency and network performance even by using high number of nodes. PMID:25202715

Lacuesta, Raquel; Sendra, Sandra; Peñalver, Lourdes

2014-01-01

430

Gain narrowing and output behavior of InP-InGaAlP tunneling injection quantum-dot-well laser  

Microsoft Academic Search

Polarization-resolved amplified spontaneous emission (ASE) and gain from tensile-strained multiple quantum wells (QWs) coupled to a single layer of compressively strained quantum dots (QDs) show interesting output characteristics. Low current injection reveals transverse electric polarized ASE from the QD ground state and QD-coupled-QW state. Additionally, transverse magnetic ASE from the QW state is observed. The modal gain of this laser

Piotr Konrad Kondratko; Shun-Lien Chuang; Gabriel Walter; Jr. N. Holonyak; R. D. Heller; Xuebing Zhang; R. D. Dupuis

2005-01-01

431

Blue shift of spontaneous emission in hyperbolic metamaterial.  

PubMed

Spontaneous emission is one of the most fundamental quantum phenomena in optics. Following the seminal work of Purcell and in agreement with the Fermi's Golden Rule, its rate can be controlled with the photonic density of states (PDOS). In recent years, this effect has been demonstrated in metamaterials with hyperbolic dispersion--highly anisotropic composite materials, which have a broad-band singularity of the density of photonic states. At this time, we show that hyperbolic metamaterials can control spontaneous emission spectra as well. Experimentally, DCM laser dye has been embedded into lamellar metal/dielectric metamaterial. The observed 18?nm blue shift of emission is explained by strong dispersion of the density of photonic states. On the other hand, practically no spectral shift has been observed in the excitation spectra of the same dye. This suggests that the effect of PDOS on spontaneous emission is very different from its effect on excitation and absorption. PMID:24957679

Gu, Lei; Tumkur, T U; Zhu, G; Noginov, M A

2014-01-01

432

Scalar gain interpretation of large order filters  

NASA Technical Reports Server (NTRS)

A technique is developed which demonstrates how to interpret a large fully-populated filter gain matrix as a set of scalar gains. The inverse problem is also solved, namely, how to develop a large-order filter gain matrix from a specified set of scalar gains. Examples are given to illustrate the method.

Mason, Paul A. C.; Mook, D. Joseph

1993-01-01

433

The kinetics of methotrexate distribution in spontaneous canine lymphosarcoma  

Microsoft Academic Search

A mathematical model is presented to simulate the time-dependent uptake of methotrexate in spontaneous canine lymphosarcomas in vivo.Blood flow rates in these tumors are high so that transport to the tumor is limited by cell membrane resistance. A significant amount of rapidly exchangeable methotrexate appears to exist in extracellular space loosely bound to proteins or cell membranes. Transmembrane drug transport

Robert J. Lutz; Robert L. Dedrick; James A. Straw; Michael M. Hart; Philip Klubes; Daniel S. Zaharko

1975-01-01

434

Hierarchical organization of a reference system in newborn spontaneous movements  

Microsoft Academic Search

In this paper, we studied spontaneous newborn movements regarding the coordination of the four limbs, arms and legs, from a dynamic perspective. We used the method of recurrence plots to analyse the kinematic data from audiovisual recordings of neonates. We identified temporal and spatial synchronization of the four limbs that resulted in high recurrence patterns of biomechanical reference configurations. Furthermore,

Birte Aßmann; M. Carmen Romano; Marco Thiel; Carsten Niemitz

2007-01-01

435

Optical gain characteristics in Al-rich AlGaN/AlN quantum wells  

SciTech Connect

The optical gain characteristics of Al-rich AlGaN/AlN quantum wells (QWs) were assessed by the variable stripe length method at room temperature. An Al{sub 0.79}Ga{sub 0.21}N/AlN QW with a well width of 5?nm had a large optical gain of 140?cm{sup ?1}. Increasing the excitation length induced a redshift due to the gain consumption and the consequent saturation of the amplified spontaneous emission. Moreover, a change in the dominant gain polarization with Al composition, which was attributed to switching of the valence band ordering of strained AlGaN/AlN QWs at Al compositions of ?0.8, was experimentally demonstrated.

Oto, Takao; Banal, Ryan G.; Funato, Mitsuru; Kawakami, Yoichi, E-mail: kawakami@kuee.kyoto-u.ac.jp [Department of Electronic Science and Engineering, Kyoto University, Kyoto 615-8510 (Japan)

2014-05-05

436

Multiple Spontaneous Simultaneous Intracerebral Hemorrhages  

PubMed Central

Simultaneous occurrence of intracerebral hemorrhage (ICH) in different arterial territories is an uncommon event. We report on two cases of multiple spontaneous simultaneous ICH for which we could find no specific cause. A 73-year-old man, with no related medical history, was admitted to the hospital with simultaneous bithalamic ICH, and subsequently died of recurrent pneumonia. Second patient was a 60-year-old man who presented with simultaneous ICH in the pons and thalamus; he died of recurrent bleeding. We review the possible pathological mechanisms, clinical and radiologic features of simultaneous multiple ICH. PMID:25045650

Seo, Jin-Suk; Nam, Taek-Kyun; Kwon, Jeong-Taik

2014-01-01

437

Spontaneously walking discrete cavity solitons.  

PubMed

We study the dynamics of oscillating discrete solitons in an array of coupled Kerr-nonlinear cavities. They emanate from stationary discrete cavity solitons due to Hopf instability and are very robust. We show that these oscillating solitons can spontaneously lose their spatial symmetry and start rocking around the equilibrium position. Moreover they can suddenly jump to adjacent resonators starting a chaotic motion along the array, resembling the Brownian motion of particles. We also identify the parameter domain where they move with constant velocity across the array. PMID:23546226

Egorov, O A; Lederer, F

2013-04-01

438

Commutated automatic gain control system  

NASA Technical Reports Server (NTRS)

The commutated automatic gain control (AGC) system was designed and built for the prototype Loran-C receiver is discussed. The current version of the prototype receiver, the Mini L-80, was tested initially in 1980. The receiver uses a super jolt microcomputer to control a memory aided phase loop (MAPLL). The microcomputer also controls the input/output, latitude/longitude conversion, and the recently added AGC system. The AGC control adjusts the level of each station signal, such that the early portion of each envelope rise is about at the same amplitude in the receiver envelope detector.

Yost, S. R.

1982-01-01

439

Primary Spontaneous Cerebrospinal Fluid Leaks and Idiopathic Intracranial Hypertension  

PubMed Central

Introduction Idiopathic intracranial hypertension (IIH) is increasingly recognized as a cause of spontaneous cerebrospinal (CSF) leak in the ENT and neurosurgical literature. The diagnosis of IIH in patients with spontaneous CSF leaks is classically made a few weeks after surgical repair of the CSF leak when symptoms and signs of elevated intracranial pressure (ICP) appear. Methods Case reports and literature review. Two young obese women developed spontaneous CSF rhinorrhea related to an empty sella in one, and a cribriform plate encephalocele in the other. Both patients underwent surgical repair of the CSF leak. A few weeks later, they developed chronic headaches and bilateral papilledema. Lumbar punctures showed elevated CSF-opening pressures with normal CSF contents, with temporary improvement of headaches. A man with a three-year history of untreated IIH developed spontaneous CSF rhinorrhea. He experienced improvement of his headaches and papilledema after a CSF shunting procedure, and the rhinorrhea resolved after endoscopic repair of the leak. Results These cases and the literature review confirm a definite association between IIH and spontaneous CSF leak based on: 1) similar demographics; 2) increased ICP in some patients with spontaneous CSF leak after leak repair; 3) higher rate of leak recurrence in patients with raised ICP; 4) patients with intracranial hypertension secondary to tumors may develop CSF leak, confirming that raised ICP from other causes than IIH can cause CSF leak. Conclusions CSF leak may occasionally keep IIH patients symptom-free; however, classic symptoms and signs of intracranial hypertension may develop after the CSF leak is repaired, exposing these patients to a high risk of recurrence of the leak unless an ICP-lowering intervention is performed. PMID:24042170

Pérez, Mario A.; Bialer, Omer Y.; Bruce, Beau B.; Newman, Nancy J.; Biousse, Valérie

2014-01-01

440

Spontaneous intraneural hematoma of the sural nerve.  

PubMed

Symptomatic intraneural hemorrhage occurs rarely. It presents with pain and/or weakness in the distribution following the anatomic innervation pattern of the involved nerve. When a purely sensory nerve is affected, the symptoms can be subtle. We present a previously healthy 36-year-old female who developed an atraumatic, spontaneous intraneural hematoma of her sural nerve. Sural dysfunction was elicited from the patient's history and physical examination. The diagnosis was confirmed with magnetic resonance imaging, and surgical decompression provided successful resolution of her preoperative symptoms. To our knowledge, this entity has not been reported previously. Our case highlights the importance of having a high index of suspicion for nerve injury or compression in patients whose complaints follow a typical peripheral nerve distribution. Prior studies have shown that the formation of intraneural hematoma and associated compression of nerve fibers result in axonal degeneration, and surgical decompression decreases axonal degeneration and aids functional recovery. PMID:25311865

Richardson, Shawn S; McLawhorn, Alexander S; Mintz, Douglas N; DiCarlo, Edward F; Weiland, Andrew J

2015-04-01

441

Surfactant therapy and spontaneous diuresis.  

PubMed

The effect of artificial surfactant therapy on renal function and the onset of spontaneous diuresis was prospectively evaluated in 19 infants with hyaline membrane disease in a double-blind, controlled study. Twelve infants were in the surfactant group; seven infants received placebo (0.9% saline solution). There was no difference in the time of onset of spontaneous diuresis (as defined by output greater than or equal to 80% of intake). The glomerular filtration rate, determined by endogenous creatinine clearance, was also similar in the surfactant- and placebo-treated infants during the first 3 days of life. The fractional excretion of sodium was significantly higher in the placebo group at 24 hours and 36 hours. Infants in the placebo group had a higher negative sodium balance than those in the surfactant group. Ventilatory status improved significantly soon after surfactant treatment, as evidenced by improvement in the alveolar/arterial oxygen pressure ratio and by a lower mean airway pressure. These data suggest that ventilatory status can be improved without diuresis; the factors that regulate diuresis are multiple and not fully understood. PMID:2646416

Bhat, R; John, E; Diaz-Blanco, J; Ortega, R; Fornell, L; Vidyasagar, D

1989-03-01

442

Combining earthquake forecasts using differential probability gains  

NASA Astrophysics Data System (ADS)

We describe an iterative method to combine seismicity forecasts. With this method, we produce the next generation of a starting forecast by incorporating predictive skill from one or more input forecasts. For a single iteration, we use the differential probability gain of an input forecast relative to the starting forecast. At each point in space and time, the rate in the next-generation forecast is the product of the starting rate and the local differential probability gain. The main advantage of this method is that it can produce high forecast rates using all types of numerical forecast models, even those that are not rate-based. Naturally, a limitation of this method is that the input forecast must have some information not already contained in the starting forecast. We illustrate this method using the Every Earthquake a Precursor According to Scale (EEPAS) and Early Aftershocks Statistics (EAST) models, which are currently being evaluated at the US testing center of the Collaboratory for the Study of Earthquake Predictability. During a testing period from July 2009 to December 2011 (with 19 target earthquakes), the combined model we produce has better predictive performance - in terms of Molchan diagrams and likelihood - than the starting model (EEPAS) and the input model (EAST). Many of the target earthquakes occur in regions where the combined model has high forecast rates. Most importantly, the rates in these regions are substantially higher than if we had simply averaged the models.

Shebalin, Peter N.; Narteau, Clément; Zechar, Jeremy Douglas; Holschneider, Matthias

2014-12-01

443

Design and fabrication of an intrinsically gain flattened Erbium doped fiber amplifier  

E-print Network

Design and fabrication of an intrinsically gain flattened Erbium doped fiber amplifier B. Nagaraju1 of an intrinsically gain flattened Erbium- doped fiber amplifier (EDFA) based on a highly asymmetrical and concentric economics is a premium, because it would cut down the cost on gain flattening filter head. Keywords: Erbium

Paris-Sud XI, Université de

444

Spontaneous emission noise in long-range surface plasmon polariton waveguide based optical gyroscope.  

PubMed

Spontaneous emission noise is an important limit to the performance of active plasmonic devices. Here, we investigate the spontaneous emission noise in the long-range surface plasmon-polariton waveguide based optical gyroscope. A theoretical model of the sensitivity is established to study the incoherent multi-beam interference of spontaneous emission in the gyroscope. Numerical results show that spontaneous emission produces a drift in the transmittance spectra and lowers the signal-to-noise-ratio of the gyroscope. It also strengthens the shot noise to be the main limit to the sensitivity of the gyroscope for high propagation loss. To reduce the negative effects of the spontaneous emission noise on the gyroscope, an external feedback loop is suggested to estimate the drift in the transmittance spectra and therefor enhance the sensitivity. Our work lays a foundation for the improvement of long-range surface plasmon-polariton gyroscope and paves the way to its practical application. PMID:25234712

Wang, Yang-Yang; Zhang, Tong

2014-01-01

445

Spontaneous adrenal haemorrhage in pregnancy  

PubMed Central

The authors present a case of spontaneous adrenal haemorrhage, in a 28-year-old woman at 36 weeks of a twin pregnancy. Initial symptom was sudden onset chest pain which soon migrated to abdomen, accompanied by hypovolaemic shock and fetal bradycardia. Subsequent caesarean section for suspected placental abruption and resuscitation with nine units of blood, 10 of cryoprecipitate, four of fresh frozen plasma and two of platelets, in order to treat anaemia of Hgb of 3.6 g/dl and disseminated intravascular coagulation, failed to stabilise the woman. A CT scan of abdomen and pelvis then revealed a 15×17×17 cm retroperitoneal haematoma, secondary to right adrenal haemorrhage. Management was with laparotomy drainage and packing of the retroperitoneal haematoma along with the use of activated factor VII. Adrenal haemorrhage in pregnancy is an extremely rare, acute, life-threatening condition, presenting with non-specific symptoms. PMID:22679231

A, Anagnostopoulos; S, Sharma

2011-01-01

446