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Sample records for compton-event suppression gamma-spectrometer

  1. Scintillation gamma spectrometer for analysis of hydraulic fracturing waste products.

    PubMed

    Ying, Leong; O'Connor, Frank; Stolz, John F

    2015-01-01

    Flowback and produced wastewaters from unconventional hydraulic fracturing during oil and gas explorations typically brings to the surface Naturally Occurring Radioactive Materials (NORM), predominantly radioisotopes from the U238 and Th232 decay chains. Traditionally, radiological sampling are performed by sending collected small samples for laboratory tests either by radiochemical analysis or measurements by a high-resolution High-Purity Germanium (HPGe) gamma spectrometer. One of the main isotopes of concern is Ra226 which requires an extended 21-days quantification period to allow for full secular equilibrium to be established for the alpha counting of its progeny daughter Rn222. Field trials of a sodium iodide (NaI) scintillation detector offers a more economic solution for rapid screenings of radiological samples. To achieve the quantification accuracy, this gamma spectrometer must be efficiency calibrated with known standard sources prior to field deployments to analyze the radioactivity concentrations in hydraulic fracturing waste products.

  2. Reanalysis of COMPTEL Measurements with the Latest Compton Event and Image Reconstruction Techniques

    NASA Astrophysics Data System (ADS)

    Zoglauer, Andreas C.; Collmar, W.; Boggs, S. E.; Hartmann, D. H.; Kippen, M.; Novikova, E. I.; Weidenspointner, G.; Wunderer, C. B.

    2010-03-01

    A decade after de-orbiting CGRO, COMPTEL's 1-30 MeV all-sky imaging data set remains unsurpassed, and no current or planned mission is capable of challenging COMPTEL's performance in the near future. Since the nineties, when the original COMPTEL data analysis techniques were developed, the performance of state-of-the-art computers has increased by orders of magnitude, enabling new and improved techniques that were out of reach at that time. We are in the progress of reanalyzing selected COMPTEL data sets with the latest Compton event and image reconstruction techniques with the goal to improve the imaging sensitivity of COMPTEL. The first step of the analysis is to reproduce the COMPTEL measurements with ab-initio simulations to achieve a better understanding of the background, to verify the simulation tools in this energy range, and to develop the capability of simulating improved response matrices. The second step is to apply modern, multi-dimensional Compton event reconstruction and selections (e.g. Bayesian event selections) to the COMPTEL data to better separate source photons from background events, and thus improving the signal to noise ratio. Finally, we developed a new imaging approach based on a partially-binned-response list-mode ML-EM, with a higher-fidelity response model than that of the original COMPTEL imaging response, which leads to improved image quality. We report on the status of the data conversion, simulations, event selections, and imaging reconstruction, and show first results from selected COMPTEL observations (e.g. Galactic anti-center, SN1998bu). This work was funded in part by NASA grant NNX08AJ38G.

  3. Investigation of cosmic-ray induced background of Germanium gamma spectrometer using GEANT4 simulation.

    PubMed

    Hung, Nguyen Quoc; Hai, Vo Hong; Nomachi, Masaharu

    2017-03-01

    In this article, a GEANT4 Monte Carlo simulation toolkit was used to study the response of the cosmic-ray induced background on a High-Purity Germanium (HPGe) gamma spectrometer in the wide energy range, up to 100MeV. The natural radiation background measurements of the spectrometer were carried out in the energy region from 0.04 to 50MeV. The simulated cosmic-ray induced background of the Ge detector was evaluated in comparison with the measured data. The contribution of various cosmic-ray components including muons, neutrons, protons, electrons, positrons and photons was investigated. We also analyzed secondary particle showers induced by the muonic component.

  4. Highly Sensitive Gamma-Spectrometers of Gerda for Material Screening: Part 2

    SciTech Connect

    Budjas, Dusan; Hampel, W.; Heisel, M.; Heusser, G.; Keillor, Marty; Laubenstein, M.; Maneschg, W.; Rugel, G.; Schonert, S.; Simgen, H.; Strecker, H.

    2007-04-21

    The previous article about material screening for Gerda points out the importance of strict material screening and selection for radioimpurities as a key to meet the aspired background levels of the Gerda experiment. This is directly done using low-level gammaspectroscopy. In order to provide sufficient selective power in the mBq/kg range and below, the employed gamma-spectrometers themselves have to meet strict material requirements, and make use of an elaborate shielding system. This article gives an account of the setup of two such spectrometers. Corrado is located in a depth of 15 m w.e. at the MPI-K in Heidelberg (Germany), Gempi III is situated at the Gran-Sasso underground laboratory at 3500 m w.e. (Italy). The latter one aims at detecting sample activities of the order ~10 μBq/kg, which is the current state-of-the-art level. The applied techniques to meet the respective needs are discussed and demonstrated by experimental results.

  5. Combined, solid-state molecular property and gamma spectrometers for CBRNE detection

    NASA Astrophysics Data System (ADS)

    Rogers, Ben; Grate, Jay; Pearson, Brett; Gallagher, Neal; Wise, Barry; Whitten, Ralph; Adams, Jesse

    2013-05-01

    Nevada Nanotech Systems, Inc. (Nevada Nano) has developed a multi-sensor solution to Chemical, Biological, Radiological, Nuclear and Explosives (CBRNE) detection that combines the Molecular Property Spectrometer™ (MPS™)—a micro-electro-mechanical chip-based technology capable of measuring a variety of thermodynamic and electrostatic molecular properties of sampled vapors and particles—and a compact, high-resolution, solid-state gamma spectrometer module for identifying radioactive materials, including isotopes used in dirty bombs and nuclear weapons. By conducting multiple measurements, the system can provide a more complete characterization of an unknown sample, leading to a more accurate identification. Positive identifications of threats are communicated using an integrated wireless module. Currently, system development is focused on detection of commercial, military and improvised explosives, radioactive materials, and chemical threats. The system can be configured for a variety of CBRNE applications, including handheld wands and swab-type threat detectors requiring short sample times, and ultra-high sensitivity detectors in which longer sampling times are used. Here we provide an overview of the system design and operation and present results from preliminary testing.

  6. NaI(Tl) scintillator read out with SiPM array for gamma spectrometer

    NASA Astrophysics Data System (ADS)

    Huang, Tuchen; Fu, Qibin; Lin, Shaopeng; Wang, Biao

    2017-04-01

    The NaI(Tl) scintillator is widely used in gamma spectrometer with photomultiplier tube (PMT) readout. Recently developed silicon photomultiplier (SiPM) offers gain and efficiency similar to those of PMT, but with merits such as low bias voltage, compact volume, low cost, high ruggedness and magnetic resonance compatibility. In this study, 2-in. and 1-in. NaI(Tl) scintillators were readout with SiPM arrays, which were made by tiling multiple SiPMs each with an active area of 6×6 mm2 on a printed circuit board. The energy resolutions for 661.6 keV gamma rays, obtained with Φ2×2 in. scintillator coupled to 6×6 ch SiPM array and Φ1×1 in. scintillator coupled to 4×4 ch SiPM array were 7.6% and 7.8%, respectively, and were very close to the results obtained with traditional bialkali PMT (7.3% and 7.6%, respectively). Scintillator coupled to photodetector with smaller area was also studied by adding a light guide or using scintillator with tapered head. The latter showed better performance than using light guide. The 1-in. NaI(Tl) scintillator with tapered head coupled to 2×2 ch SiPM array achieved 7.7% energy resolution at 661.6 keV, the same as that obtained with standard Φ1×1 in. scintillator coupled to 4×4 ch SiPM array. While the 2-in. scintillator with similar geometry showed degraded energy resolution, 10.2% at 661.6 keV, but could still be used when high efficiency is preferred over energy resolution.

  7. Implementation of a new gamma spectrometer on the MERARG loop: Application to the volatile fission products release measurement

    SciTech Connect

    Bernard, S.; Gleizes, B.; Pontillon, Y.; Hanus, E.; Ducros, G.; Roure, C.

    2015-07-01

    The MERARG facility initially aims at the annealing of irradiated fuel samples to study the gaseous fission products release kinetics. In order to complete the evaluation of the source term potentially released during accidental situation, the MERARG experimental circuit has been enhanced with a new gamma spectrometer. This one is directly sighting the fuel and is devoted to the fission products release kinetics. Because of the specificities of the fuel measurements, it has been dimensioned and designed to match the specific requirements. The acquisition chain and the collimation system have been optimized for this purpose and a first set of two experiments have shown the good functioning of this new spectrometry facility. (authors)

  8. Efficiency calibration and minimum detectable activity concentration of a real-time UAV airborne sensor system with two gamma spectrometers.

    PubMed

    Tang, Xiao-Bin; Meng, Jia; Wang, Peng; Cao, Ye; Huang, Xi; Wen, Liang-Sheng; Chen, Da

    2016-04-01

    A small-sized UAV (NH-UAV) airborne system with two gamma spectrometers (LaBr3 detector and HPGe detector) was developed to monitor activity concentration in serious nuclear accidents, such as the Fukushima nuclear accident. The efficiency calibration and determination of minimum detectable activity concentration (MDAC) of the specific system were studied by MC simulations at different flight altitudes, different horizontal distances from the detection position to the source term center and different source term sizes. Both air and ground radiation were considered in the models. The results obtained may provide instructive suggestions for in-situ radioactivity measurements of NH-UAV.

  9. Development and Characterization of a High Resolution Portable Gamma Spectrometer

    NASA Astrophysics Data System (ADS)

    Ali, Muhammad

    The recent disaster of Fukushima in Japan combined with the high demand to enhance nuclear safety and to minimize personal exposure to radioactive materials has a significant impact on research and development of radiation detection instrumentation. Currently, there is ample effort worldwide in the pursuit of radiation detection to maximize the accuracy and meet international standards in terms of size and specifications to enable radiation protection decision making. Among the requirements is the development of a portable, light-weight gamma-ray isotope identifier to be used by first responders in nuclear accidents as well as for radiation security and identification of illicit material isotopes. From nuclear security perspective, research into advanced screening technologies has become a high priority in all aspects, while for occupational safety, and environmental radiation protection, the regulatory authorities are requiring specific performance of radiation detection and measuring devices. At the applied radiation laboratory of the University of Ontario Institute of Technology, UOIT, the development of a high resolution spectrometer for medium and high energy gamma ray has been conducted. The spectrometer used a newly developed scintillator based on a LaBr3(Ce) crystal. The detector has been modeled using advanced Monte Carlo code (MCNP/X code) for the response function simulation and parameter characterization. The simulation results have been validated by experimental investigations using a wide range of gamma radiation energies. The developed spectrometer has been characterized in terms of resolution and response in different fields. It has also been compared with other crystals such as NaI(TI) and LiI(Eu).

  10. Dexamethasone suppression test

    MedlinePlus

    DST; ACTH suppression test; Cortisol suppression test ... During this test, you will receive dexamethasone. This is a strong man-made (synthetic) glucocorticoid medication. Afterward, your blood is drawn ...

  11. Fire Suppression and Response

    NASA Technical Reports Server (NTRS)

    Ruff, Gary A.

    2004-01-01

    This report is concerned with the following topics regarding fire suppression:What is the relative effectiveness of candidate suppressants to extinguish a representative fire in reduced gravity, including high-O2 mole fraction, low -pressure environments? What are the relative advantages and disadvantages of physically acting and chemically-acting agents in spacecraft fire suppression? What are the O2 mole fraction and absolute pressure below which a fire cannot exist? What effect does gas-phase radiation play in the overall fire and post-fire environments? Are the candidate suppressants effective to extinguish fires on practical solid fuels? What is required to suppress non-flaming fires (smoldering and deep seated fires) in reduced gravity? How can idealized space experiment results be applied to a practical fire scenario? What is the optimal agent deployment strategy for space fire suppression?

  12. Hail suppression and society.

    PubMed

    Changnon, S A; Farhar, B C; Swanson, E R

    1978-04-28

    An interdisciplinary assessment of hail suppression in the past, present, and future has shown it to be currently scientifically uncertain but a potentially beneficial future technology. An established suppression technology would be widely adopted in the Great Plains, providing benefits to agriculture and secondarily to the American consumer. Development of a reliable technology will require a sizable longterm federal commitment to atmospheric and social research. Subcritical funding would be a mistake. Orderly future usage of hail suppression, with its scientific complexities and regional character, will necessitate development of governmental regulations, evaluation procedures, interstate arrangements, and means for compensating those who lose from modification.

  13. Growth hormone suppression test

    MedlinePlus

    GH suppression test; Glucose loading test; Acromegaly - blood test; Gigantism - blood test ... At least 3 blood samples are taken. The test is done in the following way: The first blood sample is collected between 6 ...

  14. Jet Noise Suppression

    NASA Technical Reports Server (NTRS)

    Gliebe, P. R.; Brausch, J. F.; Majjigi, R. K.; Lee, R.

    1991-01-01

    The objectives of this chapter are to review and summarize the jet noise suppression technology, to provide a physical and theoretical model to explain the measured jet noise suppression characteristics of different concepts, and to provide a set of guidelines for evolving jet noise suppression designs. The underlying principle for all jet noise suppression devices is to enhance rapid mixing (i.e., diffusion) of the jet plume by geometric and aerothermodynamic means. In the case of supersonic jets, the shock-cell broadband noise reduction is effectively accomplished by the elimination or mitigation of the shock-cell structure. So far, the diffusion concepts have predominantly concentrated on jet momentum and energy (kinetic and thermal) diffusion, in that order, and have yielded better noise reduction than the simple conical nozzles. A critical technology issue that needs resolution is the effect of flight on the noise suppression potential of mechanical suppressor nozzles. A more thorough investigation of this mechanism is necessary for the successful development and design of an acceptable noise suppression device for future high-speed civil transports.

  15. Explosion suppression system

    DOEpatents

    Sapko, Michael J.; Cortese, Robert A.

    1992-01-01

    An explosion suppression system and triggering apparatus therefor are provided for quenching gas and dust explosions. An electrically actuated suppression mechanism which dispenses an extinguishing agent into the path ahead of the propagating flame is actuated by a triggering device which is light powered. This triggering device is located upstream of the propagating flame and converts light from the flame to an electrical actuation signal. A pressure arming device electrically connects the triggering device to the suppression device only when the explosion is sensed by a further characteristic thereof beside the flame such as the pioneer pressure wave. The light powered triggering device includes a solar panel which is disposed in the path of the explosion and oriented between horizontally downward and vertical. Testing mechanisms are also preferably provided to test the operation of the solar panel and detonator as well as the pressure arming mechanism.

  16. Sensory suppression during feeding

    PubMed Central

    Foo, H.; Mason, Peggy

    2005-01-01

    Feeding is essential for survival, whereas withdrawal and escape reactions are fundamentally protective. These critical behaviors can compete for an animal's resources when an acutely painful stimulus affects the animal during feeding. One solution to the feeding-withdrawal conflict is to optimize feeding by suppressing pain. We examined whether rats continue to feed when challenged with a painful stimulus. During feeding, motor withdrawal responses to noxious paw heat either did not occur or were greatly delayed. To investigate the neural basis of sensory suppression accompanying feeding, we recorded from brainstem pain-modulatory neurons involved in the descending control of pain transmission. During feeding, pain-facilitatory ON cells were inhibited and pain-inhibitory OFF cells were excited. When a nonpainful somatosensory stimulus preactivated ON cells and preinhibited OFF cells, rats interrupted eating to react to painful stimuli. Inactivation of the brainstem region containing ON and OFF cells also blocked pain suppression during eating, demonstrating that brainstem pain-modulatory neurons suppress motor reactions to external stimulation during homeostatic behaviors. PMID:16275919

  17. Learning motion discrimination with suppressed and un-suppressed MT.

    PubMed

    Thompson, Benjamin; Liu, Zili

    2006-06-01

    Perceptual learning of motion direction discrimination is generally thought to rely on the middle temporal area of the brain (MT/V5). A recent study investigating learning of motion discrimination when MT was psychophysically suppressed found that learning was possible with suppressed MT, but only when the task was sufficiently easy [Lu, H., Qian, N., Liu, Z. (2004). Learning motion discrimination with suppressed MT. Vision Research 44, 1817-1825]. We investigated whether this effect was indeed due to MT suppression or whether it could be explained by task difficulty alone. By comparing learning of motion discrimination when MT was suppressed vs. un-suppressed, at different task difficulties, we found that task difficulty alone could not explain the effects. At the highest difficulty, learning was not possible with suppressed MT, confirming [Lu, H., Qian, N., Liu, Z. (2004). Learning motion discrimination with suppressed MT. Vision Research 44, 1817-1825]. In comparison, learning was possible with un-suppressed MT at the same difficulty level. At the intermediate task difficulty, there was a clear learning disadvantage when MT was suppressed. Only for the easiest level of difficulty, did learning become equally possible for both suppressed and un-suppressed conditions. These findings suggest that MT plays an important role in learning to discriminate relatively fine differences in motion direction.

  18. Pressure suppression containment system

    DOEpatents

    Gluntz, D.M.; Townsend, H.E.

    1994-03-15

    A pressure suppression containment system includes a containment vessel surrounding a reactor pressure vessel and defining a drywell therein containing a non-condensable gas. An enclosed wetwell pool is disposed inside the containment vessel, and a gravity driven cooling system (GDCS) pool is disposed above the wetwell pool in the containment vessel. The wetwell pool includes a plenum for receiving the non-condensable gas carried with steam from the drywell following a loss-of-coolant-accident (LOCA). The wetwell plenum is vented to a plenum above the GDCS pool following the LOCA for suppressing pressure rise within the containment vessel. A method of operation includes channeling steam released into the drywell following the LOCA into the wetwell pool for cooling along with the non-condensable gas carried therewith. The GDCS pool is then drained by gravity, and the wetwell plenum is vented into the GDCS plenum for channeling the non-condensable gas thereto. 6 figures.

  19. Pressure suppression containment system

    DOEpatents

    Gluntz, Douglas M.; Townsend, Harold E.

    1994-03-15

    A pressure suppression containment system includes a containment vessel surrounding a reactor pressure vessel and defining a drywell therein containing a non-condensable gas. An enclosed wetwell pool is disposed inside the containment vessel, and a gravity driven cooling system (GDCS) pool is disposed above the wetwell pool in the containment vessel. The wetwell pool includes a plenum for receiving the non-condensable gas carried with steam from the drywell following a loss-of coolant-accident (LOCA). The wetwell plenum is vented to a plenum above the GDCS pool following the LOCA for suppressing pressure rise within the containment vessel. A method of operation includes channeling steam released into the drywell following the LOCA into the wetwell pool for cooling along with the non-condensable gas carried therewith. The GDCS pool is then drained by gravity, and the wetwell plenum is vented into the GDCS plenum for channeling the non-condensable gas thereto.

  20. Drug Insight: appetite suppressants.

    PubMed

    Bray, George A

    2005-02-01

    The term 'appetite suppressant' is used to denote drugs that act primarily on the neurochemical transmitters of the central nervous system to reduce food intake. In addition to drugs that release or mimic the effect of norepinephrine (noradrenaline), this could include drugs that inhibit: reuptake of norepinephrine or 5-hydroxytryptamine (also known as serotonin); bind to the gamma-aminobutyric acid receptors or the cannabinoid receptors; and some peptides that reduce food intake. The sympathomimetic drugs phentermine, diethylpropion, benzphetamine, and phendimetrazine--so named because they mimic many effects of norepinephrine--are only approved in a few countries, and then only for short-term use. Sibutramine, a norepinephrine-5-hydroxytryptamine reuptake inhibitor, is approved for long-term use. Several new mechanisms for drug action are under investigation. Appetite suppressants should be viewed as useful adjuncts to diet and physical activity and might help selected patients to achieve and maintain weight loss.

  1. Tactile suppression of displacement.

    PubMed

    Ziat, Mounia; Hayward, Vincent; Chapman, C Elaine; Ernst, Marc O; Lenay, Charles

    2010-10-01

    In vision, the discovery of the phenomenon of saccadic suppression of displacement has made important contributions to the understanding of the stable world problem. Here, we report a similar phenomenon in the tactile modality. When scanning a single Braille dot with two fingers of the same hand, participants were asked to decide whether the dot was stationary or whether it was displaced from one location to another. The stimulus was produced by refreshable Braille devices that have dots that can be swiftly raised and recessed. In some conditions, the dot was stationary. In others, a displacement was created by monitoring the participant's finger position and by switching the dot activation when it was not touched by either finger. The dot displacement was of either 2.5 mm or 5 mm. We found that in certain cases, displaced dots were felt to be stationary. If the displacement was orthogonal to the finger movements, tactile suppression occurred effectively when it was of 2.5 mm, but when the displacement was of 5 mm, the participants easily detected it. If the displacement was medial-lateral, the suppression effect occurred as well, but less often when the apparent movement of the dot opposed the movement of the finger. In such cases, the stimulus appeared sooner than when the brain could predict it from finger movement, supporting a predictive rather than a postdictive differential processing hypothesis.

  2. Next generation fire suppressants

    NASA Technical Reports Server (NTRS)

    Brown, Jerry A.

    1995-01-01

    Spectrex, Inc., located in Cedar Grove, NJ is a manufacturer of fire detection and suppression equipment. Spectrex is one of the original pioneers in high speed fire detection and suppression systems for combat vehicles. Spectrex has installed fire suppressions systems in thousands of combat vehicles and ships throughout the world. Additionally, they manufacture flame explosion detectors, ship damage control systems, and optical gas and vapor detectors. The culmination of several years of research and development has recently produced an innovative electro-optical continuous monitoring systems called SharpEye 20/20I IR(sup 3) and SAFEYE that provide fast and reliable gas, vapor, aerosol, flame, and explosion detection. SharpEye 20/20I IR(sup 3) is a self-contained triple spectrum flame detector which scans for oscillating IR radiation (1 to 10 Hz) in the spectral bands ranging from 4.0 to 5.0 microns and uses programmed algorithms to check the ratio and correlation of data received by the three sensors to make the system highly immune to false alarms. It is extremely sensitive as it can detect a 1 x 1 square foot gasoline pan fire at 200 feet in less than 3 seconds. The sensitivity is user programmable, offering 4 ranges of detection. SAFEYE is comprised of a selected number of multispectral ban microprocessors controlled detectors which are in communication with one or more radiation sources that is projected along a 600 feet optical path. The signals from the selected narrow bands are processed and analyzed by highly sophisticated algorithms. It is ideal for high risk, remote, large areas such as petroleum and chemical manufacturing sites, waste dumps, aircraft cargo bays, and ship compartments. The SAFEYE will perform direct readings of the presence or rate of rise of concentrations of gases, vapors, or aerosols at the range of parts per million and provide alarms at various set points at different levels of concentrations.

  3. Development and Performance Characteristics of Personal Gamma Spectrometer for Radiation Monitoring Applications

    PubMed Central

    Park, Hye Min; Joo, Koan Sik

    2016-01-01

    In this study, a personal gamma (γ) spectrometer was developed for use in applications in various fields, such as homeland security and environmental radiation monitoring systems. The prototype consisted of a 3 × 3 × 20 mm3 Ce-doped Gd–Al–Ga–garnet (Ce:GAGG) crystal that was coupled to a Si photomultiplier (SiPM) to measure γ radiation. The γ spectrometer could be accessed remotely via a mobile device. At room temperature, the implemented Ce:GAGG-SiPM spectrometer achieved energy resolutions of 13.5%, 6.9%, 5.8%, and 2.3% for 133Ba at 0.356 MeV, 22Na at 0.511 MeV, 137Cs at 0.662 MeV, and 60Co at 1.33 MeV, respectively. It consumed only about 2.7 W of power, had a mass of just 340 g (including the battery), and measured only 5.0 × 7.0 cm2. PMID:27338392

  4. Design, calibration, and application of an airborne gamma spectrometer system in Switzerland

    SciTech Connect

    Schwarz, G.F.; Rybach, L.; Klingele, E.E.

    1997-09-01

    Airborne radiometric surveys are finding increasingly wider application in environmental mapping and monitoring. They are the most efficient tool to delimit surface contamination and to locate lost radioactive sources. To secure radiometric capability in survey and emergency situations, a new sensitive airborne system has been built that includes an airborne spectrometer with 256 channels and a sodium iodide detector with a total volume of 16.8 liters. A rack-mounted PC with memory cards is used for data acquisition, with a GPS satellite navigation system for positioning. The system was calibrated with point sources using a mathematical correction to take into account the effects of gamma-ray scattering in the ground and in the atmosphere. The calibration was complemented by high precision ground gamma spectrometry and laboratory measurements on rock samples. In Switzerland, two major research programs make use of the capabilities of airborne radiometric measurements. The first one concerns nuclear power-plant monitoring. The five Swiss nuclear installations (four power plants and one research facility) and the surrounding regions of each site are surveyed annually. The project goal is to monitor the dose-rate distribution and to provide a documented baseline database. The measurements show that all sites (with the exception of the Goesgen power plant) can be identified clearly on the maps. No artificial radioactivity that could not be explained by the Chernobyl release or earlier nuclear weapons tests was detected outside of the fenced sites of the nuclear installations. The second program aims at a better evaluation of the natural radiation level in Switzerland. The survey focused on the crystalline rocks of the Central Massifs of the Swiss Alps because of their relatively high natural radioactivity and lithological variability.

  5. Contribution of 210Pb bremsstrahlung to the background of lead shielded gamma spectrometers

    NASA Astrophysics Data System (ADS)

    Mrđa, D.; Bikit, I.; Vesković, M.; Forkapić, S.

    2007-03-01

    Lead, which is often used as a shielding material, contains 210Pb ( T1/2=22.3 y). The 46.54 keV γ-intensity of 210Pb can be easily reduced by an inner lining, but the bremsstrahlung caused by the β-decay of its daughter, 210Bi, with a maximal electron energy of 1.16 MeV, will contribute to the gamma detector background. The spectrum of this bremsstrahlung is calculated by numerically fitting the β-spectrum and integrating the Koch-Motz formula. The absorption of the bremsstrahlung in the lead and detection efficiencies for the HPGe detector are calculated by the effective solid angle algorithm, using corrections for the photopeak/Compton ratio of cross-sections in Ge. By comparison with the measured background spectrum, it is shown that, for the lead with 25 Bq/kg of 210Pb up to 500 keV of gamma spectrum, the bremsstrahlung contribution to the background is about 20% for our surface-based detector system. Also, we compared our calculations with a Monte Carlo simulation of another detector system with a shield containing 1 Bq/kg of 210Pb and found that our analytical method gives a value of roughly two times higher than the Monte Carlo one for the total bremsstrahlung contribution. The quality of the analytical semi-empirical method is proved by the reasonable agreement with the experimental results published.

  6. Development and Performance Characteristics of Personal Gamma Spectrometer for Radiation Monitoring Applications.

    PubMed

    Park, Hye Min; Joo, Koan Sik

    2016-06-21

    In this study, a personal gamma (γ) spectrometer was developed for use in applications in various fields, such as homeland security and environmental radiation monitoring systems. The prototype consisted of a 3 × 3 × 20 mm³ Ce-doped Gd-Al-Ga-garnet (Ce:GAGG) crystal that was coupled to a Si photomultiplier (SiPM) to measure γ radiation. The γ spectrometer could be accessed remotely via a mobile device. At room temperature, the implemented Ce:GAGG-SiPM spectrometer achieved energy resolutions of 13.5%, 6.9%, 5.8%, and 2.3% for (133)Ba at 0.356 MeV, (22)Na at 0.511 MeV, (137)Cs at 0.662 MeV, and (60)Co at 1.33 MeV, respectively. It consumed only about 2.7 W of power, had a mass of just 340 g (including the battery), and measured only 5.0 × 7.0 cm².

  7. Suppression subtractive hybridization.

    PubMed

    Ghorbel, Mohamed T; Murphy, David

    2011-01-01

    Comparing two RNA populations that differ from the effects of a single independent variable, such as a drug treatment or a specific genetic defect, can establish differences in the abundance of specific transcripts that vary in a population dependent manner. There are different methods for identifying differentially expressed genes. These methods include microarray, Serial Analysis of Gene Expression (SAGE), and quantitative Reverse-Transcriptase Polymerase Chain Reaction (qRT-PCR). Herein, the protocol describes an easy and cost-effective alternative that does not require prior knowledge of the transcriptomes under examination. It is specifically relevant when low levels of RNA starting material are available. This protocol describes the use of Switching Mechanism At RNA Termini Polymerase Chain Reaction (SMART-PCR) to amplify cDNA from small amounts of RNA. The amplified cDNA populations under comparison are then subjected to Suppression Subtractive Hybridization (SSH-PCR). SSH-PCR is a technique that couples subtractive hybridization with suppression PCR to selectively amplify fragments of differentially expressed genes. The resulting products are cDNA populations enriched for significantly overrepresented transcripts in either of the two input RNAs. These cDNA populations can then be cloned to generate subtracted cDNA library. Microarrays made with clones from the subtracted forward and reverse cDNA libraries are then screened for differentially expressed genes using targets generated from tester and driver total RNAs.

  8. Pharmacology of appetite suppression.

    PubMed

    Halford, J C; Blundell, J E

    2000-01-01

    Despite a rising worldwide epidemic of obesity there is currently only a very small number of anti-obesity drugs available to manage the problem. Large numbers of differing pharmacological agents reliably produce a reduction in food intake when administered acutely to animals, and when administered chronically they result in a significant decrease in body mass. Behavioural analysis of drug-induced anorexia in animals demonstrates that various compounds profoundly effect feeding behaviour in differing ways. This indicates the variety of mechanisms by which pharmacological agents can induce changes in food intake, body weight and eventually body composition. Some of the same drugs produce decreases in food intake and weight loss in humans. Some of these drugs do so by modifying the functioning of the appetite system as measured by subjective changes in feelings of hunger and fullness (indices of satiety). Such drugs can be considered as "appetite suppressants" with clinical potential as anti-obesity agents. Other drugs induce changes in food intake and body weight through various physiological mechanisms inducing feelings of nausea or even by side effect related malaise. Of the drugs considered suitable candidates for appetite suppressants are agents which act via peripherally satiety peptide systems (such as CCK, Bombesin/GRP, Enterostatin and GLP-1), or alter the CNS levels of various hypothalamic neuropeptides (NPY, Galanin, Orexin and Melanocortins) or levels of the key CNS appetite monoamine neurotransmitters such as serotonin (5-HT) and noradrenaline (NA). Recently, the hormone leptin has been regarded as a hormonal signal linking adipose tissue status with a number of key central nervous system circuits. The peptide itself stimulates leptin receptors and it links with POMC and MC-4 receptors. These receptors may also provide drug targets for the control of appetite. Any changes induced by a potential appetite suppressant should be considered in terms of the (i

  9. Pressure suppression system

    DOEpatents

    Gluntz, Douglas M.

    1994-01-01

    A pressure suppression system includes a containment vessel surrounding a reactor pressure vessel and defining a drywell therein containing a non-condensable gas. An enclosed wetwell pool is disposed inside the containment vessel, and an enclosed gravity driven cooling system (GDCS) pool is disposed above the wetwell pool in the containment vessel. The GDCS pool includes a plenum for receiving through an inlet the non-condensable gas carried with steam from the drywell following a loss-of-coolant accident (LOCA). A condenser is disposed in the GDCS plenum for condensing the steam channeled therein and to trap the non-condensable gas therein. A method of operation includes draining the GDCS pool following the LOCA and channeling steam released into the drywell following the LOCA into the GDCS plenum for cooling along with the non-condensable gas carried therewith for trapping the gas therein.

  10. ZERO SUPPRESSION FOR RECORDERS

    DOEpatents

    Fort, W.G.S.

    1958-12-30

    A zero-suppression circuit for self-balancing recorder instruments is presented. The essential elements of the circuit include a converter-amplifier having two inputs, one for a reference voltage and the other for the signal voltage under analysis, and a servomotor with two control windings, one coupled to the a-c output of the converter-amplifier and the other receiving a reference input. Each input circuit to the converter-amplifier has a variable potentiometer and the sliders of the potentiometer are ganged together for movement by the servoinotor. The particular noveity of the circuit resides in the selection of resistance values for the potentiometer and a resistor in series with the potentiometer of the signal circuit to ensure the full value of signal voltage variation is impressed on a recorder mechanism driven by servomotor.

  11. Pressure suppression system

    DOEpatents

    Gluntz, D.M.

    1994-10-04

    A pressure suppression system includes a containment vessel surrounding a reactor pressure vessel and defining a drywell therein containing a non-condensable gas. An enclosed wetwell pool is disposed inside the containment vessel, and an enclosed gravity driven cooling system (GDCS) pool is disposed above the wetwell pool in the containment vessel. The GDCS pool includes a plenum for receiving through an inlet the non-condensable gas carried with steam from the drywell following a loss-of-coolant accident (LOCA). A condenser is disposed in the GDCS plenum for condensing the steam channeled therein and to trap the non-condensable gas therein. A method of operation includes draining the GDCS pool following the LOCA and channeling steam released into the drywell following the LOCA into the GDCS plenum for cooling along with the non-condensable gas carried therewith for trapping the gas therein. 3 figs.

  12. Ultrasonic Frost Suppression

    NASA Astrophysics Data System (ADS)

    Adachi, Kazunari; Saiki, Kazushi; Sato, Hiroki; Ito, Takahiro

    2003-02-01

    The authors have observed the accumulation of frost on the surface of a rectangular aluminum alloy (duralumin) plate flexurally vibrating at approximately 37 kHz in an atmosphere of almost 100% relative humidity at 2°C. The plate surface, which had been prepolished with abrasive slurry for maintaining its average surface roughness of about 100 nm, was refrigerated at a temperature of -20°C with cold carbon-dioxide gas as coolant. Experiments have been conducted with and without fine silver oxide powder spread on the plate surface so as to examine the effect of artificial ice crystal nuclei. Ultrasonic vibrations with an amplitude of 3.4 μm (rms) are found to suppress frost accumulation by approximately 60%. The phenomenon cannot be ascribed directly to the heat generation caused by high-amplitude vibration, but may have a complex mechanical and/or acoustical effect on small ice crystals.

  13. Factors influencing dust suppressant effectiveness

    SciTech Connect

    Copeland, C.R.; Eisele, T.C.; Chesney, D.J.; Kawatra, S.K.

    2008-11-15

    Water sprays are a common method used to reduce particulate matter (PM) emissions. Various factors such as wettability, surface area coverage, fine particle engulfment rates, interparticle adhesion forces, suppressant penetration and suppressant longevity have all been suggested as critical factors in achieving effective PM control. However, it has not been established which of these factors are the most important. Experimental work indicated that suppressant penetration is the most critical of these factors. The length of time after application that suppressants were effective was also improved by using hygroscopic reagents that retained moisture to prevent evaporation. Maximizing suppressant penetration and improving suppressant longevity led to an average 86% reduction in PM10 concentrations in laboratory dust tower tests.

  14. The site of saccadic suppression.

    PubMed

    Thilo, Kai V; Santoro, Loredana; Walsh, Vincent; Blakemore, Colin

    2004-01-01

    During rapid eye movements, or saccades, stable vision is maintained by active reduction of visual sensitivity. The site of this saccadic suppression remains uncertain. Here we show that phosphenes--small illusory visual perceptions--induced by transcranial magnetic stimulation (TMS) to the human occipital cortex are immune to saccadic suppression, whereas phosphenes induced by retinal stimulation are not, thus providing direct physiological evidence that saccadic suppression occurs between the retina and the occipital visual cortex.

  15. STRV Cryocooler Tip Motion Suppression

    NASA Technical Reports Server (NTRS)

    Glaser, R.; Ross, R. G., Jr.; Johnson, D. L.

    1994-01-01

    The Space Technology Research Vehicle (STRV-1b) scheduled to fly at the beginning of June 1994, has a cryocooler vibration suppression experiment aboard doing motion suppression of the tip of the coldfinger. STRV-1b is a bread box sized satellite to be launched on the next flight of the Ariane-4.

  16. An Alternative to Thought Suppression?

    ERIC Educational Resources Information Center

    Boice, Robert

    2012-01-01

    Comments on the original article, "Setting free the bears: Escape from thought suppression," by D. M. Wegner (see record 2011-25622-008). While Wegner supposed that we might have to learn to live with bad thoughts, the present author discusses the use of imagination and guided imagery as an alternative to forced thought suppression.

  17. Inducing amnesia through systemic suppression

    PubMed Central

    Hulbert, Justin C.; Henson, Richard N.; Anderson, Michael C.

    2016-01-01

    Hippocampal damage profoundly disrupts the ability to store new memories of life events. Amnesic windows might also occur in healthy people due to disturbed hippocampal function arising during mental processes that systemically reduce hippocampal activity. Intentionally suppressing memory retrieval (retrieval stopping) reduces hippocampal activity via control mechanisms mediated by the lateral prefrontal cortex. Here we show that when people suppress retrieval given a reminder of an unwanted memory, they are considerably more likely to forget unrelated experiences from periods surrounding suppression. This amnesic shadow follows a dose-response function, becomes more pronounced after practice suppressing retrieval, exhibits characteristics indicating disturbed hippocampal function, and is predicted by reduced hippocampal activity. These findings indicate that stopping retrieval engages a suppression mechanism that broadly compromises hippocampal processes and that hippocampal stabilization processes can be interrupted strategically. Cognitively triggered amnesia constitutes an unrecognized forgetting process that may account for otherwise unexplained memory lapses following trauma. PMID:26977589

  18. Painful consequences of anger suppression.

    PubMed

    Quartana, Phillip J; Burns, John W

    2007-05-01

    The authors experimentally examined the effects of anger suppression on pain perception. On the basis of ironic process theory, they proposed that efforts to suppress experiential or expressive components of anger may paradoxically enhance cognitive accessibility of anger-related thoughts and feelings, thereby contaminating perception of succeeding pain in an anger-congruent manner. Participants were randomly assigned to nonsuppression or experiential or expressive suppression conditions during mental arithmetic with or without harassment. A cold-pressor task followed. Results revealed that participants instructed to suppress experiential or expressive components of emotion during harassment not only reported the greatest pain levels, but also rated the anger-specific dimensions of pain uniquely strong. Results suggest that attempts to suppress anger may amplify pain sensitivity by ironically augmenting perception of the irritating and frustrating qualities of pain.

  19. Simple suppression of radiation damping.

    PubMed

    Khitrin, A K; Jerschow, Alexej

    2012-12-01

    Radiation damping is known to cause line-broadening and frequency shifts of strong resonances in NMR spectra. While several techniques exist for the suppression of these effects, many require specialized hardware, or are only compatible with the presence of few strong resonances. We describe a simple pulse sequence for radiation damping suppression in spectra with many strong resonances. The sequence can be used as-is to generate simple spectra or as a signal excitation part in more advanced experiments.

  20. Suppressed Charmed B Decay

    SciTech Connect

    Snoek, Hella Leonie

    2009-06-02

    This thesis describes the measurement of the branching fractions of the suppressed charmed B0 → D*- a0+ decays and the non-resonant B0 → D*- ηπ+ decays in approximately 230 million Υ(4S) → B$\\bar{B}$ events. The data have been collected with the BABAR detector at the PEP-II B factory at the Stanford Linear Accelerator Center in California. Theoretical predictions of the branching fraction of the B0 → D*- a{sub 0}+ decays show large QCD model dependent uncertainties. Non-factorizing terms, in the naive factorization model, that can be calculated by QCD factorizing models have a large impact on the branching fraction of these decay modes. The predictions of the branching fractions are of the order of 10-6. The measurement of the branching fraction gives more insight into the theoretical models. In general a better understanding of QCD models will be necessary to conduct weak interaction physics at the next level. The presence of CP violation in electroweak interactions allows the differentiation between matter and antimatter in the laws of physics. In the Standard Model, CP violation is incorporated in the CKM matrix that describes the weak interaction between quarks. Relations amongst the CKM matrix elements are used to present the two relevant parameters as the apex of a triangle (Unitarity Triangle) in a complex plane. The over-constraining of the CKM triangle by experimental measurements is an important test of the Standard Model. At this moment no stringent direct measurements of the CKM angle γ, one of the interior angles of the Unitarity Triangle, are available. The measurement of the angle γ can be performed using the decays of neutral B mesons. The B0 → D*- a0+ decay is sensitive to the angle γ and, in comparison to the current decays that are being employed, could significantly

  1. The amphetamine appetite suppressant saga.

    PubMed

    2004-02-01

    (1) In 1999, all amphetamine derivatives still sold in France as appetite suppressants were withdrawn from the market because of serious cardiovascular adverse effects. Sibutramine, marketed in France since 2001, is closely related to this group of drugs. (2) The adverse effects shared by these drugs are mainly neuropsychiatric (due to a psychostimulant action) and cardiovascular (arterial hypertension and tachycardia). (3) More specific cardiovascular adverse effects, such as pulmonary hypertension and severe cardiac valve damage, emerged after several years of use. The first reports date back to the 1960s. (4) The pulmonary hypertension associated with appetite suppressants can be fatal or necessitate transplantation. (5) Cardiac valve damage due to appetite suppressants is generally irreversible and sometimes requires surgery.

  2. Visual Surround Suppression in Schizophrenia

    PubMed Central

    Tibber, Marc S.; Anderson, Elaine J.; Bobin, Tracy; Antonova, Elena; Seabright, Alice; Wright, Bernice; Carlin, Patricia; Shergill, Sukhwinder S.; Dakin, Steven C.

    2013-01-01

    Compared to unaffected observers patients with schizophrenia (SZ) show characteristic differences in visual perception, including a reduced susceptibility to the influence of context on judgments of contrast – a manifestation of weaker surround suppression (SS). To examine the generality of this phenomenon we measured the ability of 24 individuals with SZ to judge the luminance, contrast, orientation, and size of targets embedded in contextual surrounds that would typically influence the target’s appearance. Individuals with SZ demonstrated weaker SS compared to matched controls for stimuli defined by contrast or size, but not for those defined by luminance or orientation. As perceived luminance is thought to be regulated at the earliest stages of visual processing our findings are consistent with a suppression deficit that is predominantly cortical in origin. In addition, we propose that preserved orientation SS in SZ may reflect the sparing of broadly tuned mechanisms of suppression. We attempt to reconcile these data with findings from previous studies. PMID:23450069

  3. Noise suppressing capillary separation system

    DOEpatents

    Yeung, Edward S.; Xue, Yongjun

    1996-07-30

    A noise-suppressing capillary separation system for detecting the real-time presence or concentration of an analyte in a sample is provided. The system contains a capillary separation means through which the analyte is moved, a coherent light source that generates a beam which is split into a reference beam and a sample beam that irradiate the capillary, and a detector for detecting the reference beam and the sample beam light that transmits through the capillary. The laser beam is of a wavelength effective to be absorbed by a chromophore in the capillary. The system includes a noise suppressing system to improve performance and accuracy without signal averaging or multiple scans.

  4. Conditioned suppression, punishment, and aversion

    NASA Technical Reports Server (NTRS)

    Orme-Johnson, D. W.; Yarczower, M.

    1974-01-01

    The aversive action of visual stimuli was studied in two groups of pigeons which received response-contingent or noncontingent electric shocks in cages with translucent response keys. Presentation of grain for 3 sec, contingent on key pecking, was the visual stimulus associated with conditioned punishment or suppression. The responses of the pigeons in three different experiments are compared.

  5. Noise suppressing capillary separation system

    DOEpatents

    Yeung, E.S.; Xue, Y.

    1996-07-30

    A noise-suppressing capillary separation system for detecting the real-time presence or concentration of an analyte in a sample is provided. The system contains a capillary separation means through which the analyte is moved, a coherent light source that generates a beam which is split into a reference beam and a sample beam that irradiate the capillary, and a detector for detecting the reference beam and the sample beam light that transmits through the capillary. The laser beam is of a wavelength effective to be absorbed by a chromophore in the capillary. The system includes a noise suppressing system to improve performance and accuracy without signal averaging or multiple scans. 13 figs.

  6. Suppression of operant vs consummatory behavior.

    PubMed

    DeCosta, M J; Ayres, J J

    1971-07-01

    The magnitude and variability of conditioned suppression of bar pressing and dipper licking were compared. In two steady-state experiments, suppression of bar pressing was more profound and more stable from day to day. The two measures of suppression were uncorrelated as indexed by Pearson product-moment correlation coefficients computed for adjacent trials. Correlations within measures (internal consistency) were somewhat higher for the bar-press system except when a high proportion of rats completely suppressed on one of the correlated trials. In a transient state experiment in which possible adventitious punishment of both response systems was eliminated, suppression of bar pressing was again more profound and considerably slower to extinguish.

  7. Fire suppression and detection equipment

    SciTech Connect

    E.E. Bates

    2006-01-15

    Inspection and testing guidelines go beyond the 'Code of Federal Regulation'. Title 30 of the US Code of Federal Regulations (30 CFR) contains requirements and references to national standards for inspection, testing and maintenance of fire suppression and detection equipment for mine operators. However, federal requirements have not kept pace with national standards and best practices. The article lists National Fire Protection (NFPA) standards that are referenced by the US Mine Safety and Health Administration (MSHA) in 30 CFR. It then discusses other NFPA Standards excluded from 30 CFR and explains the NFPA standard development process. 2 refs., 3 tabs., 5 photos.

  8. Menstrual suppression in special circumstances.

    PubMed

    Kirkham, Yolanda A; Ornstein, Melanie P; Aggarwal, Anjali; McQuillan, Sarah; Allen, Lisa; Millar, Debra; Dalziel, Nancy; Gascon, Suzy; Hakim, Julie; Ryckman, Julie; Spitzer, Rachel; Van Eyk, Nancy

    2014-10-01

    Objectif : Offrir, aux fournisseurs de soins de santé, un document de consensus canadien comptant des recommandations pour ce qui est de la suppression menstruelle chez les patientes qui font face à des obstacles physiques et/ou cognitifs ou chez les patientes qui font l’objet d’un traitement contre le cancer et pour lesquelles les règles pourraient exercer un effet délétère sur la santé. Options : Le présent document analyse les options disponibles aux fins de la suppression menstruelle, les indications, les contre-indications et les effets indésirables (tant immédiats qu’à long terme) propres à cette dernière, et les explorations et le monitorage nécessaires tout au long de la suppression. Issues : Les cliniciens seront mieux renseignés au sujet des options et des indications propres à la suppression menstruelle chez les patientes qui présentent des déficiences cognitives et/ou physiques et chez les patientes qui font l’objet d’une chimiothérapie, d’une radiothérapie ou d’autres traitements contre le cancer. Résultats : La littérature publiée a été récupérée par l’intermédiaire de recherches menées dans Medline, EMBASE, OVID et The Cochrane Library au moyen d’un vocabulaire contrôlé et de mots clés appropriés (p. ex. « heavy menstrual bleeding », « menstrual suppression », « chemotherapy/radiation », « cognitive disability », « physical disability », « learning disability »). Les résultats ont été restreints aux analyses systématiques, aux essais comparatifs randomisés, aux études observationnelles et aux études pilotes. Aucune restriction n’a été imposée en matière de langue ou de date. Les recherches ont été mises à jour de façon régulière et du nouveau matériel a été intégré à la directive clinique jusqu’en septembre 2013. La littérature grise (non publiée) a été identifiée par l’intermédiaire de recherches menées dans les sites Web d

  9. Orientation-tuned suppression in binocular rivalry reveals general and specific components of rivalry suppression.

    PubMed

    Stuit, Sjoerd M; Cass, John; Paffen, Chris L E; Alais, David

    2009-10-16

    During binocular rivalry (BR), conflicting monocular images are alternately suppressed from awareness. During suppression of an image, contrast sensitivity for probes is reduced by approximately 0.3-0.5 log units relative to when the image is in perceptual dominance. Previous studies on rivalry suppression have led to controversies concerning the nature and extent of suppression during BR. We tested for feature-specific suppression using orthogonal rivaling gratings and measuring contrast sensitivity to small grating probes at a range of orientations in a 2AFC orientation discrimination task. Results indicate that suppression is not uniform across orientations: suppression was much greater for orientations close to that of the suppressed grating. The higher suppression was specific to a narrow range around the suppressed rival grating, with a tuning similar to V1 orientation bandwidths. A similar experiment tested for spatial frequency tuning and found that suppression was stronger for frequencies close to that of the suppressed grating. Interestingly, no tuned suppression was observed when a flicker-and-swap paradigm was used, suggesting that tuned suppression occurs only for lower-level, interocular rivalry. Together, the results suggest there are two components to rivalry suppression: a general feature-invariant component and an additional component specifically tuned to the rivaling features.

  10. Suppressed epidemics in multirelational networks

    NASA Astrophysics Data System (ADS)

    Xu, Elvis H. W.; Wang, Wei; Xu, C.; Tang, Ming; Do, Younghae; Hui, P. M.

    2015-08-01

    A two-state epidemic model in networks with links mimicking two kinds of relationships between connected nodes is introduced. Links of weights w1 and w0 occur with probabilities p and 1 -p , respectively. The fraction of infected nodes ρ (p ) shows a nonmonotonic behavior, with ρ drops with p for small p and increases for large p . For small to moderate w1/w0 ratios, ρ (p ) exhibits a minimum that signifies an optimal suppression. For large w1/w0 ratios, the suppression leads to an absorbing phase consisting only of healthy nodes within a range pL≤p ≤pR , and an active phase with mixed infected and healthy nodes for p pR . A mean field theory that ignores spatial correlation is shown to give qualitative agreement and capture all the key features. A physical picture that emphasizes the intricate interplay between infections via w0 links and within clusters formed by nodes carrying the w1 links is presented. The absorbing state at large w1/w0 ratios results when the clusters are big enough to disrupt the spread via w0 links and yet small enough to avoid an epidemic within the clusters. A theory that uses the possible local environments of a node as variables is formulated. The theory gives results in good agreement with simulation results, thereby showing the necessity of including longer spatial correlations.

  11. Water Mist fire suppression experiment

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The Water Mist commercial research program is scheduled to fly an investigation on STS-107 in 2002. This investigation will be flown as an Experimental Mounting Structure (EMS) insert into the updated Combustion Module (CM-2), a sophisticated combustion chamber plus diagnostic equipment. (The investigation hardware is shown here mounted in a non-flight frame similar to the EMS.) Water Mist is a commercial research program by the Center for Commercial Applications of Combustion in Space (CCACS), a NASA Commercial Space Center located at the Colorado School of Mines, in Golden, CO and Industry Partner Environmental Engineering Concepts. The program is focused on developing water mist as a replacement for bromine-based chemical fire suppression agents (halons). By conducting the experiments in microgravity, interference from convection currents is minimized and fundamental knowledge can be gained. This knowledge is incorporated into models, which can be used to simulate a variety of physical environments. The immediate objective of the project is to study the effect of a fine water mist on a laminar propagating flame generated in a propane-air mixture at various equivalence ratios. The effects of droplet size and concentration on the speed of the flame front is used as a measure of the effectiveness of fire suppression in this highly controlled experimental environment.

  12. Use of a shielded low resolution gamma spectrometer for segregation of free release and low level waste

    SciTech Connect

    Wilkins, C.G.; Alvarez, E.; Cocks, J.; Davison, L.; Mattinson, A.

    2007-07-01

    In the UK, low level radioactive waste (LLW) is sent to the national Low Level Waste Repository (LLWR) at Drigg in Cumbria. Strict rules limit the specific activity of waste that is sent to the LLW Repository and waste producers and consignors have to demonstrate that the waste they send to the repository meets its conditions for acceptance. However, the limited capacity of the Low Level Waste Repository means that it is just as important for waste consignees to ensure that inactive 'free release' or 'exempt' waste is not inadvertently sent to the repository. Incorrect segregation of waste in a decommissioning activity can mean that large amounts of the waste produced is below the exemption limit and could therefore be disposed of in conventional landfill. Sellafield Ltd. is using a pair of Canberra WM2750 Clearance Monitors to assay 100 litre packages of soft waste produced in some of their decommissioning activities at Sellafield. The WM2750 uses low resolution gamma spectrometry (LRGS) to determine the radionuclide content of packages or drums of LLW up to a maximum of 140 litre capacity. It uses a lead shielded measurement chamber to reduce the local radiation background along with high efficiency sodium iodide (NaI) detectors in order to obtain the measurement sensitivity required to be able to distinguish between LLW and exempt waste in a measurement time of less than 1 minute per package. This paper describes the waste monitoring process and the design of the clearance monitor - in particular how it was calibrated and the performance testing that was carried out to ensure that waste items identified by the monitors as being exempt waste are suitable for disposal to a conventional landfill site. (authors)

  13. Transparent ceramic garnet scintillator optimization via composition and co-doping for high-energy resolution gamma spectrometers (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Cherepy, Nerine J.; Payne, Stephen A.; Seeley, Zachary M.; Beck, Patrick R.; Swanberg, Erik L.; Hunter, Steven L.

    2016-09-01

    Breakthrough energy resolution, R(662keV) <4%, has been achieved with an oxide scintillator, Cerium-doped Gadolinium Yttrium Gallium Aluminum Garnet, or GYGAG(Ce), by optimizing fabrication conditions. Here we describe the dependence of scintillation light yield and energy resolution on several variables: (1) Stoichiometry, in particular Gd/Y and Ga/Al ratios which modify the bandgap energy, (2) Processing methods, including vacuum vs. oxygen sintering, and (3) Trace co-dopants that influence the formation of Ce4+ and modify the intra-bandgap trap distribution. To learn about how chemical composition influences the scintillation properties of transparent ceramic garnet scintillators, we have measured: scintillation decay component amplitudes; intensity and duration of afterglow; thermoluminescence glow curve peak positions and amplitudes; integrated light yield; light yield non-proportionality, as measured in the Scintillator Light Yield Non-Proportionality Characterization Instrument (SLYNCI); and energy resolution for gamma spectroscopy. Optimized GYGAG(Ce) provides R(662 keV) =3.0%, for 0.05 cm3 size ceramics with Silicon photodiode readout, and R(662 keV) =4.6%, at 2 in3 size with PMT readout.

  14. How to suppress undesired synchronization.

    PubMed

    Louzada, V H P; Araújo, N A M; Andrade, J S; Herrmann, H J

    2012-01-01

    Examples of synchronization can be found in a wide range of phenomena such as neurons firing, lasers cascades, chemical reactions, and opinion formation. However, in many situations the formation of a coherent state is not pleasant and should be mitigated. For example, the onset of synchronization can be the root of epileptic seizures, traffic congestion in networks, and the collapse of constructions. Here we propose the use of contrarians to suppress undesired synchronization. We perform a comparative study of different strategies, either requiring local or total knowledge, and show that the most efficient one solely requires local information. Our results also reveal that, even when the distribution of neighboring interactions is narrow, significant improvement is observed when contrarians sit at the highly connected elements. The same qualitative results are obtained for artificially generated networks and two real ones, namely, the Routers of the Internet and a neuronal network.

  15. Elastic Suppression of Viscous Fingering

    NASA Astrophysics Data System (ADS)

    Peng, Gunnar; Lister, John

    2016-11-01

    Consider peeling an elastic tape or beam away from a rigid base to which it is stuck by a film of viscous liquid. The peeling motion requires air to invade the viscous liquid and is thus susceptible to the Saffman-Taylor fingering instability. We analyse the fundamental travelling-wave solution and show that the advancing air-liquid interface remains linearly stable at higher capillary numbers than in a standard Hele-Shaw cell. A short-wavelength expansion yields an analytical expression for the growth rate which is valid for all unstable modes throughout the parameter space, allowing us to identify and quantify four distinct physical mechanisms that each help suppress the instability. Applying our method to the experiments by Pihler-Puzovic et al. (2012) reveals that the radial geometry and time-variation stabilize the system further.

  16. How to suppress undesired synchronization

    PubMed Central

    Louzada, V. H. P.; Araújo, N. A. M.; Andrade, J. S.; Herrmann, H. J.

    2012-01-01

    Examples of synchronization can be found in a wide range of phenomena such as neurons firing, lasers cascades, chemical reactions, and opinion formation. However, in many situations the formation of a coherent state is not pleasant and should be mitigated. For example, the onset of synchronization can be the root of epileptic seizures, traffic congestion in networks, and the collapse of constructions. Here we propose the use of contrarians to suppress undesired synchronization. We perform a comparative study of different strategies, either requiring local or total knowledge, and show that the most efficient one solely requires local information. Our results also reveal that, even when the distribution of neighboring interactions is narrow, significant improvement is observed when contrarians sit at the highly connected elements. The same qualitative results are obtained for artificially generated networks and two real ones, namely, the Routers of the Internet and a neuronal network. PMID:22993685

  17. Tactile stimulation can suppress visual perception

    PubMed Central

    Ide, Masakazu; Hidaka, Souta

    2013-01-01

    An input (e.g., airplane takeoff sound) to a sensory modality can suppress the percept of another input (e.g., talking voices of neighbors) of the same modality. This perceptual suppression effect is evidence that neural responses to different inputs closely interact with each other in the brain. While recent studies suggest that close interactions also occur across sensory modalities, crossmodal perceptual suppression effect has not yet been reported. Here, we demonstrate that tactile stimulation can suppress the percept of visual stimuli: Visual orientation discrimination performance was degraded when a tactile vibration was applied to the observer's index finger of hands. We also demonstrated that this tactile suppression effect on visual perception occurred primarily when the tactile and visual information were spatially and temporally consistent. The current findings would indicate that neural signals could closely and directly interact with each other, sufficient to induce the perceptual suppression effect, even across sensory modalities. PMID:24336391

  18. Tactile stimulation can suppress visual perception.

    PubMed

    Ide, Masakazu; Hidaka, Souta

    2013-12-13

    An input (e.g., airplane takeoff sound) to a sensory modality can suppress the percept of another input (e.g., talking voices of neighbors) of the same modality. This perceptual suppression effect is evidence that neural responses to different inputs closely interact with each other in the brain. While recent studies suggest that close interactions also occur across sensory modalities, crossmodal perceptual suppression effect has not yet been reported. Here, we demonstrate that tactile stimulation can suppress the percept of visual stimuli: Visual orientation discrimination performance was degraded when a tactile vibration was applied to the observer's index finger of hands. We also demonstrated that this tactile suppression effect on visual perception occurred primarily when the tactile and visual information were spatially and temporally consistent. The current findings would indicate that neural signals could closely and directly interact with each other, sufficient to induce the perceptual suppression effect, even across sensory modalities.

  19. MEK5 suppresses osteoblastic differentiation

    SciTech Connect

    Kaneshiro, Shoichi; Otsuki, Dai; Yoshida, Kiyoshi; Yoshikawa, Hideki; Higuchi, Chikahisa

    2015-07-31

    Extracellular signal-regulated kinase 5 (ERK5) is a member of the mitogen-activated protein kinase (MAPK) family and is activated by its upstream kinase, MAPK kinase 5 (MEK5), which is a member of the MEK family. Although the role of MEK5 has been investigated in several fields, little is known about its role in osteoblastic differentiation. In this study, we have demonstrated the role of MEK5 in osteoblastic differentiation in mouse preosteoblastic MC3T3-E1 cells and bone marrow stromal ST2 cells. We found that treatment with BIX02189, an inhibitor of MEK5, increased alkaline phosphatase (ALP) activity and the gene expression of ALP, osteocalcin (OCN) and osterix, as well as it enhanced the calcification of the extracellular matrix. Moreover, osteoblastic cell proliferation decreased at a concentration of greater than 0.5 μM. In addition, knockdown of MEK5 using siRNA induced an increase in ALP activity and in the gene expression of ALP, OCN, and osterix. In contrast, overexpression of wild-type MEK5 decreased ALP activity and attenuated osteoblastic differentiation markers including ALP, OCN and osterix, but promoted cell proliferation. In summary, our results indicated that MEK5 suppressed the osteoblastic differentiation, but promoted osteoblastic cell proliferation. These results implied that MEK5 may play a pivotal role in cell signaling to modulate the differentiation and proliferation of osteoblasts. Thus, inhibition of MEK5 signaling in osteoblasts may be of potential use in the treatment of osteoporosis. - Highlights: • MEK5 inhibitor BIX02189 suppresses proliferation of osteoblasts. • MEK5 knockdown and MEK5 inhibitor promote differentiation of osteoblasts. • MEK5 overexpression inhibits differentiation of osteoblasts.

  20. Two Techniques For Suppressing Vibrations In Structures

    NASA Technical Reports Server (NTRS)

    Chen, Gun-Shing; Garba, John A.; Wada, Ben K.

    1991-01-01

    Two techniques intended to be used together to suppress vibrations in large, complicated truss structure involve combination of active and passive damping. Based on bridge feedback and criterion for placement of actuators. Research continues to develop system using these and other techniques to suppress vibrations in, and help control shape of, truss structure in outer space that supports precise, segmented reflector of communication antenna. On Earth, developmental techniques applicable to suppression of vibrations in bridges and tall buildings.

  1. Acoustic Suppression Systems and Related Methods

    NASA Technical Reports Server (NTRS)

    Kolaini, Ali R. (Inventor); Kern, Dennis L. (Inventor)

    2013-01-01

    An acoustic suppression system for absorbing and/or scattering acoustic energy comprising a plurality of acoustic targets in a containment is described, the acoustic targets configured to have resonance frequencies allowing the targets to be excited by incoming acoustic waves, the resonance frequencies being adjustable to suppress acoustic energy in a set frequency range. Methods for fabricating and implementing the acoustic suppression system are also provided.

  2. ISS Update: Burning and Suppression of Solids

    NASA Video Gallery

    ISS Update Commentator Pat Ryan interviews Paul Ferkul, Principal Investigator for the Burning and Suppression of Solids (BASS) experiment, about performing combustion experiments in microgravity. ...

  3. Issues in Numerical Simulation of Fire Suppression

    SciTech Connect

    Tieszen, S.R.; Lopez, A.R.

    1999-04-12

    This paper outlines general physical and computational issues associated with performing numerical simulation of fire suppression. Fire suppression encompasses a broad range of chemistry and physics over a large range of time and length scales. The authors discuss the dominant physical/chemical processes important to fire suppression that must be captured by a fire suppression model to be of engineering usefulness. First-principles solutions are not possible due to computational limitations, even with the new generation of tera-flop computers. A basic strategy combining computational fluid dynamics (CFD) simulation techniques with sub-grid model approximations for processes that have length scales unresolvable by gridding is presented.

  4. Bone suppression technique for chest radiographs

    NASA Astrophysics Data System (ADS)

    Huo, Zhimin; Xu, Fan; Zhang, Jane; Zhao, Hui; Hobbs, Susan K.; Wandtke, John C.; Sykes, Anne-Marie; Paul, Narinder; Foos, David

    2014-03-01

    High-contrast bone structures are a major noise contributor in chest radiographic images. A signal of interest in a chest radiograph could be either partially or completely obscured or "overshadowed" by the highly contrasted bone structures in its surrounding. Thus, removing the bone structures, especially the posterior rib and clavicle structures, is highly desirable to increase the visibility of soft tissue density. We developed an innovative technology that offers a solution to suppress bone structures, including posterior ribs and clavicles, on conventional and portable chest X-ray images. The bone-suppression image processing technology includes five major steps: 1) lung segmentation, 2) rib and clavicle structure detection, 3) rib and clavicle edge detection, 4) rib and clavicle profile estimation, and 5) suppression based on the estimated profiles. The bone-suppression software outputs an image with both the rib and clavicle structures suppressed. The rib suppression performance was evaluated on 491 images. On average, 83.06% (±6.59%) of the rib structures on a standard chest image were suppressed based on the comparison of computer-identified rib areas against hand-drawn rib areas, which is equivalent to about an average of one rib that is still visible on a rib-suppressed image based on a visual assessment. Reader studies were performed to evaluate reader performance in detecting lung nodules and pneumothoraces with and without a bone-suppression companion view. Results from reader studies indicated that the bone-suppression technology significantly improved radiologists' performance in the detection of CT-confirmed possible nodules and pneumothoraces on chest radiographs. The results also showed that radiologists were more confident in making diagnoses regarding the presence or absence of an abnormality after rib-suppressed companion views were presented

  5. Attentional selection by distractor suppression.

    PubMed

    Caputo, G; Guerra, S

    1998-03-01

    Selective attention was studied in displays containing singletons popping out for their odd form or color. The target was defined as the form-singleton, the distractor as the color-singleton. The task was to discriminate the length of a longer line inside the target. Target-distractor similarity was controlled using a threshold measurement as dependent variable in experiments in which distractor presence vs absence, bottom-up vs top-down selection (through knowledge of target features), and target-distractor distance were manipulated. The results in the bottom-up condition showed that length threshold was elevated when a distractor was present and that this elevation progressively increased as the number of distractors was increased from one to two. This set-size effect was not accounted by the hypothesis that selective attention intervenes only at the stage of decision before response. Selective attention produced a suppressive surround in which discriminability of neighboring objects was strongly reduced, and a larger surround in which discriminability was reduced by an approximately constant amount. Different results were found in the top-down condition in which target discriminability was unaffected by distractor presence and no effect of target-distractor distance was found. On the other hand, response times in both bottom-up and top-down conditions were slower the shorter the target-distractor distance was. On the basis of the experimental results, selective attention is a parallel process of spatial filtering at an intermediate processing level operating after objects have been segmented. This filtering stage explores high level interactions between objects taking control on combinatorial explosion by operating over only a limited spatial extent: it picks out a selected object and inhibits the neighboring objects; then, non-selected objects are suppressed across the overall image. When no feature-based selection is available in the current behavior, this

  6. New approaches to hard bubble suppression

    NASA Technical Reports Server (NTRS)

    Henry, R. D.; Besser, P. J.; Warren, R. G.; Whitcomb, E. C.

    1973-01-01

    Description of a new double-layer method for the suppression of hard bubbles that is more versatile than previously reported suppression techniques. It is shown that it may be possible to prevent hard bubble generation without recourse to exchange coupling of multilayer films.

  7. Growth suppression caused by corticosteroid eye drops.

    PubMed

    Wolthers, Ole D

    2011-01-01

    Scarce data on systemic activity of corticosteroid eye drops are available in children. Two weeks treatment with fluorometholone eye drops in a case series of five children caused growth suppression detected by knemometry. The suppression had no impact on height growth during the following year.

  8. Suppressive soils: back on the radar screen

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Suppressive soils are those in which a pathogen does not establish or persist, establishes but causes little or no damage, or establishes and causes disease for a while but thereafter the disease is less important, although the pathogen may persist in the soil (Weller, 2002). ‘General suppression,’ ...

  9. Ferromagnetic resonance probe liftoff suppression apparatus

    DOEpatents

    Davis, Thomas J.; Tomeraasen, Paul L.

    1985-01-01

    A liftoff suppression apparatus utilizing a liftoff sensing coil to sense the amount a ferromagnetic resonance probe lifts off the test surface during flaw detection and utilizing the liftoff signal to modulate the probe's field modulating coil to suppress the liftoff effects.

  10. Polypyrrole actuators for tremor suppression

    NASA Astrophysics Data System (ADS)

    Skaarup, Steen; Mogensen, Naja; Bay, Lasse; West, Keld

    2003-07-01

    Neurological tremor affecting limbs can be divided into at least 6 different types with frequencies ranging from 2 to about 20 Hz. In order to alleviate the symptoms by suppressing the tremor, sensing and actuation systems able to perform at these frequencies are needed. Electroactive polymers exemplify "soft actuator" technology that may be especially suitable for use in conjunction with human limbs. The electrochemical and mechanical properties of polypyrrole dodecyl benzene sulphonate actuator films have been studied with this application in mind. The results show that the time constants for the change of length and for the stiffness change are significantly different; the stiffness change being about 10 times faster. Both force measurements and Electrochemical Quartz Crystal Microbalance measurements indicate that the actuation process is complex and involves at least two different processes. The EQCM results make it possible to formulate a hypothesis for the two different time constants: Sodium ions enter the polymer correlated with a fast mass change that probably involves a few (~4) strongly bound water molecules as well. On further reduction, about 10 additional water molecules enter the polymer in a slower process driven by osmotic pressure. Earlier work has tended to focus on achieving the maximum length change, therefore taking the time needed to include all processes. However, since the slower process described above is associated with the lowest strength of the actuator, concentrating on the faster stiffness change results in only a small reduction in the work done by the actuator. This may make actuation at higher frequencies feasible.

  11. Multicopy Suppression Underpins Metabolic Evolvability

    PubMed Central

    Patrick, Wayne M.; Quandt, Erik M.; Swartzlander, Dan B.; Matsumura, Ichiro

    2009-01-01

    Our understanding of the origins of new metabolic functions is based upon anecdotal genetic and biochemical evidence. Some auxotrophies can be suppressed by overexpressing substrate-ambiguous enzymes (i.e., those that catalyze the same chemical transformation on different substrates). Other enzymes exhibit weak but detectable catalytic promiscuity in vitro (i.e., they catalyze different transformations on similar substrates). Cells adapt to novel environments through the evolution of these secondary activities, but neither their chemical natures nor their frequencies of occurrence have been characterized en bloc. Here, we systematically identified multifunctional genes within the Escherichia coli genome. We screened 104 single-gene knockout strains and discovered that many (20%) of these auxotrophs were rescued by the overexpression of at least one noncognate E. coli gene. The deleted gene and its suppressor were generally unrelated, suggesting that promiscuity is a product of contingency. This genome-wide survey demonstrates that multifunctional genes are common and illustrates the mechanistic diversity by which their products enhance metabolic robustness and evolvability. PMID:17884825

  12. Transport suppression by shear reduction

    NASA Astrophysics Data System (ADS)

    Martinell, Julio; Del-Castillo-Negrete, Diego

    2009-11-01

    The relationship between transport and shear is a problem of considerable interest to magnetically confined plasmas. It is well known that there are cases in which an increase of flow shear can lead to a reduction of turbulent transport. However, this is not a generic result, and there are transport problems in which the opposite is the case. In particular, as originally discussed in Ref. footnotetextdel-Castillo-Negrete and Morrison, Phys. Fluids A 5, 948 (1993), barriers to chaotic transport typically form in regions of vanishing shear. This property, which is generic to the so-called non-twist Hamiltonian systems footnotetextdel-Castillo-Negrete, Greene, and Morrison, Physica D 91, 1 (1996), explains the observed resilience of transport barriers in non-monotonic zonal flows in plasmas and fluids and the robustness of shearless magnetic surfaces in reverse shear configurations. Here we study the role of finite Larmor radius (FLR) effects on the suppression of chaotic transport by shear reduction in a simplified model. Following Ref. footnotetextdel-Castillo-Negrete, Phys. Plasmas, 7, 1702 (2000) we consider a model consisting of a superposition of drift waves and a non-monotonic zonal flow. The FLR effects are incorporated by gyroaveraging the E xB velocity, and transport is studied by following the evolution of ensembles of test particles.

  13. Impacts of suppressing guide on information spreading

    NASA Astrophysics Data System (ADS)

    Xu, Jinghong; Zhang, Lin; Ma, Baojun; Wu, Ye

    2016-02-01

    It is quite common that guides are introduced to suppress the information spreading in modern society for different purposes. In this paper, an agent-based model is established to quantitatively analyze the impacts of suppressing guides on information spreading. We find that the spreading threshold depends on the attractiveness of the information and the topology of the social network with no suppressing guides at all. Usually, one would expect that the existence of suppressing guides in the spreading procedure may result in less diffusion of information within the overall network. However, we find that sometimes the opposite is true: the manipulating nodes of suppressing guides may lead to more extensive information spreading when there are audiences with the reversal mind. These results can provide valuable theoretical references to public opinion guidance on various information, e.g., rumor or news spreading.

  14. Burst suppression probability algorithms: state-space methods for tracking EEG burst suppression

    NASA Astrophysics Data System (ADS)

    Chemali, Jessica; Ching, ShiNung; Purdon, Patrick L.; Solt, Ken; Brown, Emery N.

    2013-10-01

    Objective. Burst suppression is an electroencephalogram pattern in which bursts of electrical activity alternate with an isoelectric state. This pattern is commonly seen in states of severely reduced brain activity such as profound general anesthesia, anoxic brain injuries, hypothermia and certain developmental disorders. Devising accurate, reliable ways to quantify burst suppression is an important clinical and research problem. Although thresholding and segmentation algorithms readily identify burst suppression periods, analysis algorithms require long intervals of data to characterize burst suppression at a given time and provide no framework for statistical inference. Approach. We introduce the concept of the burst suppression probability (BSP) to define the brain's instantaneous propensity of being in the suppressed state. To conduct dynamic analyses of burst suppression we propose a state-space model in which the observation process is a binomial model and the state equation is a Gaussian random walk. We estimate the model using an approximate expectation maximization algorithm and illustrate its application in the analysis of rodent burst suppression recordings under general anesthesia and a patient during induction of controlled hypothermia. Main result. The BSP algorithms track burst suppression on a second-to-second time scale, and make possible formal statistical comparisons of burst suppression at different times. Significance. The state-space approach suggests a principled and informative way to analyze burst suppression that can be used to monitor, and eventually to control, the brain states of patients in the operating room and in the intensive care unit.

  15. Mutual Suppression: Comment on Paulhus et Al. (2004)

    ERIC Educational Resources Information Center

    Nickerson, Carol

    2008-01-01

    Paulhus, Robins, Trzesniewski, and Tracy ("Multivariate Behavioral Research," 2004, 39, 305-328) suggested that the three types of two-predictor suppression situations--classical suppression, cooperative suppression, and net suppression--can all be considered special cases of mutual suppression, in that the magnitude of each of the two…

  16. Psychopathology and Thought Suppression: A Quantitative Review

    PubMed Central

    Magee, Joshua C.; Harden, K. Paige; Teachman, Bethany A.

    2012-01-01

    Recent theories of psychopathology have suggested that thought suppression intensifies the persistence of intrusive thoughts, and proposed that difficulty with thought suppression may differ between groups with and without psychopathology. The current meta-analytic review evaluates empirical evidence for difficulty with thought suppression as a function of the presence and specific type of psychopathology. Based on theoretical proposals from the psychopathology literature, diagnosed and analogue samples were expected to show greater recurrence of intrusive thoughts during thought suppression attempts than non-clinical samples. However, results showed no overall differences in the recurrence of thoughts due to thought suppression between groups with and without psychopathology. There was, nevertheless, variation in the recurrence of thoughts across different forms of psychopathology, including relatively less recurrence during thought suppression for samples with symptoms of Obsessive-Compulsive Disorder, compared to non-clinical samples. However, these differences were typically small and provided only mixed support for existing theories. Implications for cognitive theories of intrusive thoughts are discussed, including proposed mechanisms underlying thought suppression. PMID:22388007

  17. Suppression effects in feature-based attention

    PubMed Central

    Wang, Yixue; Miller, James; Liu, Taosheng

    2015-01-01

    Attending to a feature enhances visual processing of that feature, but it is less clear what occurs to unattended features. Single-unit recording studies in middle temporal (MT) have shown that neuronal modulation is a monotonic function of the difference between the attended and neuron's preferred direction. Such a relationship should predict a monotonic suppressive effect in psychophysical performance. However, past research on suppressive effects of feature-based attention has remained inconclusive. We investigated the suppressive effect for motion direction, orientation, and color in three experiments. We asked participants to detect a weak signal among noise and provided a partially valid feature cue to manipulate attention. We measured performance as a function of the offset between the cued and signal feature. We also included neutral trials where no feature cues were presented to provide a baseline measure of performance. Across three experiments, we consistently observed enhancement effects when the target feature and cued feature coincided and suppression effects when the target feature deviated from the cued feature. The exact profile of suppression was different across feature dimensions: Whereas the profile for direction exhibited a “rebound” effect, the profiles for orientation and color were monotonic. These results demonstrate that unattended features are suppressed during feature-based attention, but the exact suppression profile depends on the specific feature. Overall, the results are largely consistent with neurophysiological data and support the feature-similarity gain model of attention. PMID:26067533

  18. Integrin endosomal signalling suppresses anoikis

    PubMed Central

    Alanko, Jonna; Mai, Anja; Jacquemet, Guillaume; Schauer, Kristine; Kaukonen, Riina; Saari, Markku; Goud, Bruno; Ivaska, Johanna

    2016-01-01

    to enhanced signalling of co-trafficked receptor tyrosine kinases10, 11 it has remained unclear whether endocytosed active integrins signal in endosomes. Here, we demonstrate that integrin signalling is not restricted to focal adhesions as previously described and that endocytosis is necessary for full ECM-induced, integrin mediated ERK, AKT and FAK signalling. We find that FAK binds directly to and can become activated on purified endosomes. Moreover, the FERM-domain of FAK is able to bind purified integrin containing endosomes, suggesting the potential for integrin signalling complexes to assemble on endosomes after internalization of active integrins. Importantly, FAK is required for anchorage-independent growth and suppression of anoikis 12. Integrin endosomal signalling correlates with reduced anoikis sensitivity in normal cells and anchorage-independent growth and metastasis in breast cancer cells. PMID:26436690

  19. Effects of tic suppression: ability to suppress, rebound, negative reinforcement, and habituation to the premonitory urge.

    PubMed

    Specht, Matt W; Woods, Douglas W; Nicotra, Cassandra M; Kelly, Laura M; Ricketts, Emily J; Conelea, Christine A; Grados, Marco A; Ostrander, Rick S; Walkup, John T

    2013-01-01

    The comprehensive behavioral intervention for tics (CBIT) represents a safe, effective non-pharmacological treatment for Tourette's disorder that remains underutilized as a treatment option. Contributing factors include the perceived negative consequences of tic suppression and the lack of a means through which suppression results in symptom improvement. Participants (n = 12) included youth ages 10-17 years with moderate-to-marked tic severity and noticeable premonitory urges who met Tourette's or chronic tic disorder criteria. Tic frequency and urge rating data were collected during an alternating sequence of tic freely or reinforced tic suppression periods. Even without specific instructions regarding how to suppress tics, youth experienced a significant, robust (72%), stable reduction in tic frequency under extended periods (40 min) of contingently reinforced tic suppression in contrast to periods of time when tics were ignored. Following periods of prolonged suppression, tic frequency returned to pre-suppression levels. Urge ratings did not show the expected increase during the initial periods of tic suppression, nor a subsequent decline in urge ratings during prolonged, effective tic suppression. Results suggest that environments conducive to tic suppression result in reduced tic frequency without adverse consequences. Additionally, premonitory urges, underrepresented in the literature, may represent an important enduring etiological consideration in the development and maintenance of tic disorders.

  20. Suppression of immune response to Listeria monocytogenes: mechanism(s) of immune complex suppression.

    PubMed Central

    Virgin, H W; Wittenberg, G F; Bancroft, G J; Unanue, E R

    1985-01-01

    We have investigated possible mechanisms underlying immune complex suppression of resistance to Listeria monocytogenes. Inhibition of resistance was found when immune complexes were formed in vivo in immune mice or in nonimmune mice adoptively transferred with specific antibody. Suppression was also found when nonimmune mice were injected with immune complexes preformed in vitro. We investigated the role of complement by decomplementing mice with cobra venom factor purified by high-pressure liquid chromatography. Complete depletion of serum C3 did not eliminate immune complex suppression of resistance to L. monocytogenes, suggesting that complement activation is not required for immune complex suppression. Infection-induced changes in the surface phenotype and functional properties of macrophages from normal and immune complex-suppressed mice were also investigated. Macrophage expression of both H-2K and Ia molecules increased during the response of normal mice to L. monocytogenes. However, these changes were not found in immune complex-suppressed mice. In contrast, membrane interleukin 1 expression was increased in macrophages from suppressed mice compared with macrophages from normal mice. Macrophages from L. monocytogenes-infected normal and immune complex-suppressed mice expressed cytotoxicity against tumor cells in vitro. We conclude that immune complexes do not inhibit resistance to L. monocytogenes by activation of complement or decreasing macrophage cytotoxic activity. Rather, defects in Ia expression by macrophages from suppressed mice might be one component responsible for immune complex suppression of resistance to L. monocytogenes. PMID:3932204

  1. Suppression factors in diffractive photoproduction of dijets

    NASA Astrophysics Data System (ADS)

    Klasen, Michael; Kramer, Gustav

    2010-11-01

    Now that new publications of H1 data for the diffractive photoproduction of dijets, which overlap with the earlier published H1 data and the recently published data of the ZEUS collaboration, have appeared, we have recalculated the cross sections for this process in next-to-leading order (NLO) of perturbative QCD to see whether they can be interpreted consistently. The results of these calculations are compared to the data of both collaborations. We find that the NLO cross sections disagree with the data, showing that factorization breaking occurs at that order. If direct and resolved contributions are both suppressed by the same amount, the global suppression factor depends on the transverse-energy cut. However, by suppressing only the resolved contribution, also reasonably good agreement with all the data is found with a suppression factor independent of the transverse-energy cut.

  2. METHOD OF SUPPRESSING GASTROINTESTINAL UREASE ACTIVITY

    DOEpatents

    Visek, W.J.

    1963-04-23

    This patent shows a method of increasing the growth rate of chicks. Certain diacyl substituted ureas such as alloxan, murexide, and barbituric acid are added to their feed, thereby suppressing gastrointestinal urease activity and thus promoting growth. (AEC)

  3. Suppression as a stereotype control strategy.

    PubMed

    Monteith, M J; Sherman, J W; Devine, P G

    1998-01-01

    Recent research reveals that efforts to suppress stereotypic thoughts can backfire and produce a rebound effect, such that stereotypic thinking increases to a level that is even greater than if no attempt at stereotype control was initially exercised (e.g., Macrae, Bodenhausen, Milne, & Jetten, 1994). The primary goal of this article is to present an in-depth theoretical analysis of stereotype suppression that identifies numerous potential moderators of the effect of stereotype suppression on the likelihood of subsequent rebound. Our analysis of stereotype suppression focuses on two broad issues: the influence of level of prejudice and the influence of processing goals on the activation versus application of stereotypes. Although stereotype rebound occurs under some circumstances, we suggest that a complete understanding of this phenomenon requires consideration of the full array of possible moderating influences.

  4. Marihuana smoking suppresses luteinizing hormone in women.

    PubMed

    Mendelson, J H; Mello, N K; Ellingboe, J; Skupny, A S; Lex, B W; Griffin, M

    1986-06-01

    Smoking a single 1-g marihuana cigarette containing 1.8% delta 9-tetrahydrocannabinol induced a 30% suppression of plasma luteinizing hormone levels (P less than .02) in women during the luteal phase of the menstrual cycle. After marihuana placebo cigarette smoking, no luteinizing hormone suppression was observed in the same women under double-blind conditions. Marihuana may have adverse effects upon reproductive function during the luteal phase of the menstrual cycle as a consequence of gonadotropin inhibition.

  5. Investigation of refracting flows for acoustic suppression

    NASA Technical Reports Server (NTRS)

    Sloan, D.; Purves, R. B.; Farquhar, B. W.

    1977-01-01

    An experimental investigation to determine the possibility of using refracting flows for the suppression of aircraft inlet noise is described. Observations of wave refraction in duct flows and measurements of the increase in effectiveness of acoustic linings due to refraction have suggested methods for the design of engine inlet ducts which can either suppress noise internally or direct it to where it causes less annoyance.

  6. Flame Suppression Agent, System and Uses

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2013-01-01

    Aqueous droplets encapsulated in a flame retardant polymer are useful in suppressing combustion. Upon exposure to a flame, the encapsulated aqueous droplets rupture and vaporize, removing heat and displacing oxygen to retard the combustion process. The polymer encapsulant, through decomposition, may further add free radicals to the combustion atmosphere, thereby further retarding the combustion process. The encapsulated aqueous droplets may be used as a replacement to halon, water mist and dry powder flame suppression systems.

  7. Measurement of myeloid cell immune suppressive activity.

    PubMed

    Dolcetti, Luigi; Peranzoni, Elisa; Bronte, Vincenzo

    2010-11-01

    This unit presents simple methods to assess the immunosuppressive properties of immunoregulatory cells of myeloid origin, such as myeloid-derived suppressor cells (MDSCs), both in vitro and in vivo. These methods are general and could be adapted to test the impact of different suppressive populations on T cell activation, proliferation, and cytotoxic activity; moreover they could be useful to assess the influence exerted on immune suppressive pathways by genetic modifications, chemical inhibitors, and drugs.

  8. Method for Transducer Transient Suppression. I. Theory

    DTIC Science & Technology

    1992-09-01

    Vol. 92, No. 3, September 1992 Method for transducer transient suppression. I: Theory Jean C. Piquette Naval Research Laboratory. Underwater Sound...TITLE AND SUBTITLE 5. FUNDING NUMBERS Method for transducer transient suppression. I: Theo:y PE - 61153N TA - RROII-08-42 WU - DN220-161 6. AUTHOR(S) Jean...STATEMENT 12b. DISTRIBUTION CODE Approved for public release; distribution unlimited. 13. ABSTRACT (Maximum 200 words) The problem of driving a transducer in

  9. Noise suppression in surface microseismic data

    USGS Publications Warehouse

    Forghani-Arani, Farnoush; Batzle, Mike; Behura, Jyoti; Willis, Mark; Haines, Seth S.; Davidson, Michael

    2012-01-01

    We introduce a passive noise suppression technique, based on the τ − p transform. In the τ − p domain, one can separate microseismic events from surface noise based on distinct characteristics that are not visible in the time-offset domain. By applying the inverse τ − p transform to the separated microseismic event, we suppress the surface noise in the data. Our technique significantly improves the signal-to-noise ratios of the microseismic events and is superior to existing techniques for passive noise suppression in the sense that it preserves the waveform. We introduce a passive noise suppression technique, based on the τ − p transform. In the τ − p domain, one can separate microseismic events from surface noise based on distinct characteristics that are not visible in the time-offset domain. By applying the inverse τ − p transform to the separated microseismic event, we suppress the surface noise in the data. Our technique significantly improves the signal-to-noise ratios of the microseismic events and is superior to existing techniques for passive noise suppression in the sense that it preserves the waveform.

  10. Suppression sours sacrifice: emotional and relational costs of suppressing emotions in romantic relationships.

    PubMed

    Impett, Emily A; Kogan, Aleksandr; English, Tammy; John, Oliver; Oveis, Christopher; Gordon, Amie M; Keltner, Dacher

    2012-06-01

    What happens when people suppress their emotions when they sacrifice for a romantic partner? This multimethod study investigates how suppressing emotions during sacrifice shapes affective and relationship outcomes. In Part 1, dating couples came into the laboratory to discuss important romantic relationship sacrifices. Suppressing emotions was associated with emotional costs for the partner discussing his or her sacrifice. In Part 2, couples participated in a 14-day daily experience study. Within-person increases in emotional suppression during daily sacrifice were associated with decreases in emotional well-being and relationship quality as reported by both members of romantic dyads. In Part 3, suppression predicted decreases in relationship satisfaction and increases in thoughts about breaking up with a romantic partner 3 months later. In the first two parts of the study, authenticity mediated the costly effects of suppression. Implications for research on close relationships and emotion regulation are discussed.

  11. The temporal frequency tuning of continuous flash suppression reveals peak suppression at very low frequencies

    PubMed Central

    Han, Shui’er; Lunghi, Claudia; Alais, David

    2016-01-01

    Continuous flash suppression (CFS) is a psychophysical technique where a rapidly changing Mondrian pattern viewed by one eye suppresses the target in the other eye for several seconds. Despite the widespread use of CFS to study unconscious visual processes, the temporal tuning of CFS suppression is currently unknown. In the present study we used spatiotemporally filtered dynamic noise as masking stimuli to probe the temporal characteristics of CFS. Surprisingly, we find that suppression in CFS peaks very prominently at approximately 1 Hz, well below the rates typically used in CFS studies (10 Hz or more). As well as a strong bias to low temporal frequencies, CFS suppression is greater for high spatial frequencies and increases with increasing masker contrast, indicating involvement of parvocellular/ventral mechanisms in the suppression process. These results are reminiscent of binocular rivalry, and unifies two phenomenon previously thought to require different explanations. PMID:27767078

  12. Feature-based attention modulates surround suppression

    PubMed Central

    Flevaris, Anastasia V.; Murray, Scott O.

    2015-01-01

    Stimuli appearing in the surround of the classical receptive field (CRF) can reduce neuronal firing and perceived contrast of a preferred stimulus in the CRF, a phenomenon referred to as surround suppression. Suppression is greatest when the surrounding stimulus has the same orientation and spatial frequency (SF) as the central target. Although spatial attention has been shown to influence surround suppression, the effects of feature-based attention have yet to be characterized. Using behavioral contrast adaptation in humans, we examined center-surround interactions between SF and orientation, and asked whether attending to one feature dimension versus the other influenced suppression. A center-surround triplet comprised of a central target Gabor and two flanking Gabors were used for adaptation. The flankers could have the same SF and orientation as the target, or differ in one or both of the feature dimensions. Contrast thresholds were measured for the target before and after adapting to center-surround triplets, and postadaptation thresholds were taken as an indirect measure of surround suppression. Both feature dimensions contributed to surround suppression and did not summate. Moreover, when center and surround had the same feature value in one dimension (e.g., same orientation) but had different values in the other dimension (e.g., different SF), there was more suppression when attention was directed to the feature dimension that matched between center and surround than when attention was directed to the feature dimension that differed. These results demonstrate that feature-based attention can influence center-surround interactions by enhancing the effects of the attended dimension. PMID:25630380

  13. CONDITIONS FOR CSR MICROBUNCHING GAIN SUPPRESSION

    SciTech Connect

    Tsai, Cheng Ying; Douglas, David R.; Li, Rui; Tennant, Christopher D.; di Mitri, Simone

    2016-05-01

    The coherent synchrotron radiation (CSR) of a high brightness electron beam traversing a series of dipoles, such as transport arcs, may result in phase space degradation. On one hand, the CSR can perturb electron transverse motion in dispersive regions along the beamline, causing emittance growth. On the other hand, the CSR effect on the longitudinal beam dynamics could result in microbunching gain enhancement. For transport arcs, several schemes have been proposed* to suppress the CSR-induced emittance growth. Similarly, several scenarios have been introduced** to suppress CSR-induced microbunching gain, which however mostly aim for linac-based machines. In this paper we try to provide sufficient conditions for suppression of CSR-induced microbunching gain along a transport arc, analogous to*. Several example lattices are presented, with the relevant microbunching analyses carried out by our semi-analytical Vlasov solver***. The simulation results show that lattices satisfying the proposed conditions indeed have microbunching gain suppressed. We expect this analysis can shed light on lattice design approach that could suppress the CSR-induced microbunching gain.

  14. Suppression of branches in Eucalyptus trees.

    PubMed

    Senthalir, P; Sharanya, S; Paramathma, M

    2004-06-01

    The effect of neem oil, which acts as a suckericide in tobacco, on branch suppression in Eucalyptus tereticornis was assessed to help maximize stem biomass. Lateral branches of selected trees were pruned, and neem oil solutions at concentrations of either 80%, 40%, 20%, 10%, or 0% (untreated control) were applied to leaf axils of the pruned branches. Regeneration of branches was suppressed, and the magnitude of suppression was proportional to the concentration of neem oil. Compared to the control, the percentage reduction in branching at 80% neem oil was 41.6%. When regenerated branches were repruned and neem oil applied at either 100%, 80%, or 0% (control), the regenerating ability of these branches was severely repressed by 78% at 100% neem oil relative to the control. Apical shoots were also topped and treated at either 100% or 0% (control) neem oil to identify the principal suppressive component in neem oil. The principal component azadirachtin was tested at 375, 750, 1500, 3125, 6250, 12 500, 25 000, 50 000, and 100 000 ppm and 0 ppm as the control. Reduction in the coppicing shoot was as high as 85%. Azadirachtin was responsible for the suppression. By pruning the lateral branches with neem oil, wasteful consumption of photosynthates can be precluded and the stem biomass maximized.

  15. Tactical Checkpoint: Hail/Warn Suppress/Stop (Poster)

    DTIC Science & Technology

    2010-11-15

    distractor , optical suppression , human behavior, checkpoint, ambient light, driver suppression , human experimentation, light, paintball, obscuration...HAIL/WARN AND - SUPPRESS /STOP Poster Presented at the 2010 Directed Energies Professional Society Meeting, 15-19 November 2010. 5a. CONTRACT NUMBER...warning to a driver that is approaching a checkpoint. The laser, MCNC light, and the windshield obscuration were evaluated for their suppression

  16. Appetite suppressants and valvular heart disease.

    PubMed

    Weissman, N J

    2001-04-01

    The association between valvular heart disease and diet pills was discovered several years ago in a small cohort of patients. Subsequent uncontrolled surveys and reports suggested a prevalence of cardiac abnormalities as high as 30%. These results led to widespread concern by millions of appetite suppressant users and the withdrawal of both fenfluramine and dexfenfluramine from the market. Through this review of the literature, it becomes apparent that we have better defined the association between valvular heart disease and appetite suppressants; nonetheless, many questions and controversies remain. Most large scale, multicenter, controlled studies have shown that a prevalence of significant valve regurgitation is between 2 and 12% and that the likelihood of disease increases with increasing dose and/or duration of appetite suppressant use, but several other issues, such as the mechanism of action, remain unanswered.

  17. Wing rock suppression using forebody vortex control

    NASA Technical Reports Server (NTRS)

    Ng, T. T.; Ong, L. Y.; Suarez, C. J.; Malcolm, G. N.

    1991-01-01

    Static and free-to-roll tests were conducted in a water tunnel with a configuration that consisted of a highly-slender forebody and 78-deg sweep delta wings. Flow visualization was performed and the roll angle histories were obtained. The fluid mechanisms governing the wing rock of this configuration were identified. Different means of suppressing wing rock by controlling the forebody vortices using small blowing jets were also explored. Steady blowing was found to be capable of suppressing wing rock, but significant vortex asymmetries had to be induced at the same time. On the other hand, alternating pulsed blowing on the left and right sides of the forebody was demonstrated to be potentially an effective means of suppressing wing rock and eliminating large asymmetric moments at high angles of attack.

  18. Implicitly learned suppression of irrelevant spatial locations.

    PubMed

    Leber, Andrew B; Gwinn, Rachael E; Hong, Yoolim; O'Toole, Ryan J

    2016-12-01

    How do we ignore a salient, irrelevant stimulus whose location is predictable? A variety of studies using instructional manipulations have shown that participants possess the capacity to exert location-based suppression. However, for the visual search challenges we face in daily life, we are not often provided explicit instructions and are unlikely to consciously deliberate on what our best strategy might be. Instead, we might rely on our past experience-in the form of implicit learning-to exert strategic control. In this paper, we tested whether implicit learning could drive spatial suppression. In Experiment 1, participants searched displays in which one location contained a target, while another contained a salient distractor. An arrow cue pointed to the target location with 70 % validity. Also, unbeknownst to the participants, the same arrow cue predicted the distractor location with 70 % validity. Results showed facilitated RTs to the predicted target location, confirming target enhancement. Critically, distractor interference was reduced at the predicted distractor location, revealing that participants used spatial suppression. Further, we found that participants had no explicit knowledge of the cue-distractor contingencies, confirming that the learning was implicit. In Experiment 2, to seek further evidence for suppression, we modified the task to include occasional masked probes following the arrow cue; we found worse probe identification accuracy at the predicted distractor location than control locations, providing converging evidence that observers spatially suppressed the predicted distractor locations. These results reveal an ecologically desirable mechanism of suppression, which functions without the need for conscious knowledge or externally guided instructions.

  19. Large-Scale Identification and Analysis of Suppressive Drug Interactions

    PubMed Central

    Cokol, Murat; Weinstein, Zohar B.; Yilancioglu, Kaan; Tasan, Murat; Doak, Allison; Cansever, Dilay; Mutlu, Beste; Li, Siyang; Rodriguez-Esteban, Raul; Akhmedov, Murodzhon; Guvenek, Aysegul; Cokol, Melike; Cetiner, Selim; Giaever, Guri; Iossifov, Ivan; Nislow, Corey; Shoichet, Brian; Roth, Frederick P.

    2014-01-01

    SUMMARY One drug may suppress the effects of another. Although knowledge of drug suppression is vital to avoid efficacy-reducing drug interactions or discover countermeasures for chemical toxins, drug-drug suppression relationships have not been systematically mapped. Here, we analyze the growth response of Saccharomyces cerevisiae to anti-fungal compound (“drug”) pairs. Among 440 ordered drug pairs, we identified 94 suppressive drug interactions. Using only pairs not selected on the basis of their suppression behavior, we provide an estimate of the prevalence of suppressive interactions between anti-fungal compounds as 17%. Analysis of the drug suppression network suggested that Bromopyruvate is a frequently suppressive drug and Staurosporine is a frequently suppressed drug. We investigated potential explanations for suppressive drug interactions, including chemogenomic analysis, coaggregation, and pH effects, allowing us to explain the interaction tendencies of Bromopyruvate. PMID:24704506

  20. Vibration Isolation, Suppression, Steering, and Pointing (VISSP)

    NASA Technical Reports Server (NTRS)

    Wada, Ben K.; Rahman, Zahidul; Kedikian, Roland

    1996-01-01

    The design of a six degree of freedom flight vibration isolation suppression and steering (VISS) subsystem for a mid-wave infrared camera on the top of a spacecraft is presented. The development of a long stroke piezoelectric, redundant, compact, low stiffness and power efficient actuator is summarized. A subsystem that could be built and validated for flight within 15 months was investigated. The goals of the VISS are 20 dB vibration isolation above 2 Hz, 15 dB vibration suppression of disturbances at about 60 Hz and 120 Hz, and +/- 0.3 deg steering at 2 Hz and 4 Hz.

  1. Active Suppression Of Vibrations On Aircraft Structures

    NASA Technical Reports Server (NTRS)

    Maestrello, Lucio

    1995-01-01

    Method of active suppression of nonlinear and nonstationary vibrations developed to reduce sonic fatigue and interior noise in high-speed aircraft. Structure of aircraft exhibits periodic, chaotic, and random vibrations when forced by high-intensity sound from jet engines, shock waves, turbulence, and separated flows. Method of suppressing vibrations involves feedback control: Strain gauges or other sensors mounted in paths of propagation of vibrations on structure sense vibrations; outputs of sensors processed into control signal applied to actuator mounted on structure, inducing compensatory forces.

  2. Immune suppressive mechanisms in the tumor microenvironment.

    PubMed

    Munn, David H; Bronte, Vincenzo

    2016-04-01

    Effective immunotherapy, whether by checkpoint blockade or adoptive cell therapy, is limited in most patients by a key barrier: the immunosuppressive tumor microenvironment. Suppression of tumor-specific T cells is orchestrated by the activity of a variety of stromal myeloid and lymphoid cells. These often display inducible suppressive mechanisms that are triggered by the same anti-tumor inflammatory response that the immunotherapy intends to create. Therefore, a more comprehensive understanding of how the immunosuppressive milieu develops and persists is critical in order to harness the full power of immunotherapy of cancer.

  3. Corticosteroids and Immune Suppressive Therapies in Horses.

    PubMed

    Leclere, Mathilde

    2017-04-01

    Immune suppressive therapies target exaggerated and deleterious responses of the immune system. Triggered by exogenous or endogenous factors, these improper responses can lead to immune or inflammatory manifestations, such as urticaria, equine asthma, or autoimmune and immune-mediated diseases. Glucocorticoids are the most commonly used immune suppressive drugs and the only ones supported by robust evidence of clinical efficacy in equine medicine. In some conditions, combining glucocorticoids with other pharmacologic and nonpharmacologic treatments, such as azathioprine, antihistamine, bronchodilators, environmental management, or desensitization, can help to decrease dosages and associated side effects.

  4. Suppressive competition: how sounds may cheat sight.

    PubMed

    Kayser, Christoph; Remedios, Ryan

    2012-02-23

    In this issue of Neuron, Iurilli et al. (2012) demonstrate that auditory cortex activation directly engages local GABAergic circuits in V1 to induce sound-driven hyperpolarizations in layer 2/3 and layer 6 pyramidal neurons. Thereby, sounds can directly suppress V1 activity and visual driven behavior.

  5. Suppression Situations in Multiple Linear Regression

    ERIC Educational Resources Information Center

    Shieh, Gwowen

    2006-01-01

    This article proposes alternative expressions for the two most prevailing definitions of suppression without resorting to the standardized regression modeling. The formulation provides a simple basis for the examination of their relationship. For the two-predictor regression, the author demonstrates that the previous results in the literature are…

  6. Characterization of Immune Suppression Induced by Polyribonucleotides.

    DTIC Science & Technology

    1985-12-01

    RD-0162 482 CHARACTERIZATION OF IMMUNE SUPPRESSION INDUCED Y v i POLYRIDONUCLEOTIDES(U) MINNESOTA UNIV DULUTH DEPT OF MEDICAL MICROBIOLOGY AND...Polyribonucleotides by Marilyn J. Odean and Arthur G. Johnson Dept. of Medical Microbiology /Immunology University of Minnesota-Duluth 55812 DTICS ELECTE DEC 18

  7. Active suppression after involuntary capture of attention.

    PubMed

    Sawaki, Risa; Luck, Steven J

    2013-04-01

    After attention has been involuntarily captured by a distractor, how is it reoriented toward a target? One possibility is that attention to the distractor passively fades over time, allowing the target to become attended. Another possibility is that the captured location is actively suppressed so that attention can be directed toward the target location. The present study investigated this issue with event-related potentials (ERPs), focusing on the N2pc component (a neural measure of attentional deployment) and the Pd component (a neural measure of attentional suppression). Observers identified a color-defined target in a search array, which was preceded by a task-irrelevant cue array. When the cue array contained an item that matched the target color, this item captured attention (as measured both behaviorally and with the N2pc component). This capture of attention was followed by active suppression (indexed by the Pd component), and this was then followed by a reorienting of attention toward the target in the search array (indexed by the N2pc component). These findings indicate that the involuntary capture of attention by a distractor is followed by an active suppression process that presumably facilitates the subsequent voluntary orienting of attention to the target.

  8. Sound-suppressing structure with thermal relief

    NASA Technical Reports Server (NTRS)

    Nash, D. O.; Holowach, J. (Inventor)

    1978-01-01

    Sound-suppressing structure comprising stacked acoustic panels wherein the inner high frequency panel is mounted for thermal expansion with respect to the outer low frequency panel is discussed. Slip joints eliminate the potential for thermal stresses, and a thermal expansion gap between the panels provides for additional relative thermal growth while reducing heat convection into the low frequency panel.

  9. Suppressed Carrier Synchronizers for ISI Channels

    NASA Technical Reports Server (NTRS)

    Hinedi, Sami M.; Simon, Marvin K.

    1996-01-01

    We demonstrate a class of suppressed carrier synchronization loops that are motivated by MAP estimation theory and in the presence of ISI outperform the conventional I-Q loop which is designed on the basis of zero ISI (wideband assumption). The measure of comparison used is the so-called.

  10. Radio science measurements with suppressed carrier

    NASA Astrophysics Data System (ADS)

    Asmar, S.; Divsalar, D.; Oudrhiri, K.; Hamkins, J.

    Radio Science started when it became apparent with early deep space missions that occultations by planetary atmospheres would affect the quality of radio communications. Since then the atmospheric properties and other aspects of planetary science, solar science, and fundamental physics were studied by scientists. Radio Science data was always extracted from a received pure residual carrier (without data modulation). For some missions, it is very desirable to obtain Radio Science data from a suppressed carrier modulation. In this paper we propose a method to extract Radio Science data when a coded suppressed carrier modulation is used in deep space communications. The type of modulation can be BPSK, QPSK, OQPSK, MPSK or even GMSK. However we concentrate mostly on BPSK modulation. The proposed method for suppressed carrier simply tries to wipe out data that acts as an interference for Radio Science measurements. In order to measure the estimation errors in amplitude and phase of the Radio Science data we use the Cramer-Rao bound (CRB). The CRB for suppressed carrier modulation with non-ideal data wiping is then compared with residual carrier modulation under the same noise condition. The method of derivation of the CRB for non-ideal data wiping is an innovative method that is presented here. Some numerical results are provided for a coded system.

  11. Radio Science Measurements with Suppressed Carrier

    NASA Technical Reports Server (NTRS)

    Asmar, Sami; Divsalar, Dariush; Oudrhiri, Kamal

    2013-01-01

    Radio Science started when it became apparent with early Solar missions that occultations by planetary atmospheres would affect the quality of radio communications. Since then the atmospheric properties and other aspects of planetary science, solar science, and fundamental physics were studied by scientists. Radio Science data was always extracted from a received pure residual carrier (without data modulation). For some missions, it is very desirable to obtain Radio Science data from a suppressed carrier modulation. In this paper we propose a method to extract Radio Science data when a coded suppressed carrier modulation is used in deep space communications. Type of modulation can be BPSK, QPSK, OQPSK, MPSK or even GMSK. However we concentrate mostly on BPSK modulation. The proposed method for suppressed carrier simply tries to wipe out data that acts as an interference for Radio Science measurements. In order to measure the estimation errors in amplitude and phase of the Radio Science data we use Cramer-Rao bound (CRB). The CRB for the suppressed carrier modulation with non-ideal data wiping is then compared with residual carrier modulation under the same noise condition. The method of derivation of CRB for non-ideal data wiping is an innovative method that presented here. Some numerical results are provided for coded system.

  12. Government Doublethink: Protection or Suppression in Information.

    ERIC Educational Resources Information Center

    Drake, Miriam A.

    2003-01-01

    Discusses regulations and actions related to government withholding, suppressing, and altering information since September 11, 2001. Topics include conflicting goals of an informed citizenry versus national security, science and technology progress versus protection of sensitive information, and public health versus ideology; political pressure;…

  13. Collective suppression of linewidths in circuit QED.

    PubMed

    Nissen, Felix; Fink, Johannes M; Mlynek, Jonas A; Wallraff, Andreas; Keeling, Jonathan

    2013-05-17

    We report the experimental observation and a theoretical explanation of collective suppression of linewidths for multiple superconducting qubits coupled to a good cavity. This demonstrates how strong qubit-cavity coupling can significantly modify the dephasing and dissipation processes that might be expected for individual qubits, and can potentially improve coherence times in many-body circuit QED.

  14. Spacecraft Fire Suppression: Testing and Evaluation

    NASA Technical Reports Server (NTRS)

    Abbud-Madrid, Angel; McKinnon, J. Thomas; Delplanque, Jean-Pierre; Kailasanath, Kazhikathra; Gokoglu, Suleyman; Wu, Ming-Shin

    2004-01-01

    The objective of this project is the testing and evaluation of the effectiveness of a variety of fire suppressants and fire-response techniques that will be used in the next generation of spacecraft (Crew Exploration Vehicle, CEV) and planetary habitats. From the many lessons learned in the last 40 years of space travel, there is common agreement in the spacecraft fire safety community that a new fire suppression system will be needed for the various types of fire threats anticipated in new space vehicles and habitats. To date, there is no single fire extinguishing system that can address all possible fire situations in a spacecraft in an effective, reliable, clean, and safe way. The testing conducted under this investigation will not only validate the various numerical models that are currently being developed, but it will provide new design standards on fire suppression that can then be applied to the next generation of spacecraft extinguishment systems. The test program will provide validation of scaling methods by conducting small, medium, and large scale fires. A variety of suppression methods will be tested, such as water mist, carbon dioxide, and nitrogen with single and multiple injection points and direct or distributed agent deployment. These injection methods cover the current ISS fire suppression method of a portable hand-held fire extinguisher spraying through a port in a rack and also next generation spacecraft units that may have a multi-point suppression delivery system built into the design. Consideration will be given to the need of a crew to clean-up the agent and recharge the extinguishers in flight in a long-duration mission. The fire suppression methods mentioned above will be used to extinguish several fire scenarios that have been identified as the most relevant to spaceflight, such as overheated wires, cable bundles, and circuit boards, as well as burning cloth and paper. Further testing will be conducted in which obstructions and

  15. Benchmark enclosure fire suppression experiments - phase 1 test report.

    SciTech Connect

    Figueroa, Victor G.; Nichols, Robert Thomas; Blanchat, Thomas K.

    2007-06-01

    A series of fire benchmark water suppression tests were performed that may provide guidance for dispersal systems for the protection of high value assets. The test results provide boundary and temporal data necessary for water spray suppression model development and validation. A review of fire suppression in presented for both gaseous suppression and water mist fire suppression. The experimental setup and procedure for gathering water suppression performance data are shown. Characteristics of the nozzles used in the testing are presented. Results of the experiments are discussed.

  16. Overcoming fixation with repeated memory suppression.

    PubMed

    Angello, Genna; Storm, Benjamin C; Smith, Steven M

    2015-01-01

    Fixation (blocks to memories or ideas) can be alleviated not only by encouraging productive work towards a solution, but, as the present experiments show, by reducing counterproductive work. Two experiments examined relief from fixation in a word-fragment completion task. Blockers, orthographically similar negative primes (e.g., ANALOGY), blocked solutions to word fragments (e.g., A_L_ _GY) in both experiments. After priming, but before the fragment completion test, participants repeatedly suppressed half of the blockers using the Think/No-Think paradigm, which results in memory inhibition. Inhibiting blockers did not alleviate fixation in Experiment 1 when conscious recollection of negative primes was not encouraged on the fragment completion test. In Experiment 2, however, when participants were encouraged to remember negative primes at fragment completion, relief from fixation was observed. Repeated suppression may nullify fixation effects, and promote creative thinking, particularly when fixation is caused by conscious recollection of counterproductive information.

  17. Glucose Suppresses Biological Ferroelectricity in Aortic Elastin

    NASA Astrophysics Data System (ADS)

    Liu, Yuanming; Wang, Yunjie; Chow, Ming-Jay; Chen, Nataly Q.; Ma, Feiyue; Zhang, Yanhang; Li, Jiangyu

    2013-04-01

    Elastin is an intriguing extracellular matrix protein present in all connective tissues of vertebrates, rendering essential elasticity to connective tissues subjected to repeated physiological stresses. Using piezoresponse force microscopy, we show that the polarity of aortic elastin is switchable by an electrical field, which may be associated with the recently discovered biological ferroelectricity in the aorta. More interestingly, it is discovered that the switching in aortic elastin is largely suppressed by glucose treatment, which appears to freeze the internal asymmetric polar structures of elastin, making it much harder to switch, or suppressing the switching completely. Such loss of ferroelectricity could have important physiological and pathological implications from aging to arteriosclerosis that are closely related to glycation of elastin.

  18. Suppression of Eimeria tenella sporulation by disinfectants.

    PubMed

    You, Myung-Jo

    2014-08-01

    The disinfectant effects (DEs) of 10 types of chemicals, defined by their ability to destroy or inhibit oocysts and consequently prevent sporulation of Eimeria tenella field isolate, were evaluated in vitro. Correct species assignments and sample purities were confirmed by the singular internal transcribed spacer (ITS)-PCR analysis. A total of 18 treatments were performed, and the disinfection suppression levels were 75.9% for 39% benzene + 22% xylene (1:10 dilution), 85.5% for 30% cresol soup (1:1 dilution), and 91.7% for 99.9% acetic acid (1:2 dilution) group. The results indicate that acetic acid, cresol soup, and benzene+xylene are good candidates for suppression of E. tenella oocyst sporulation.

  19. Suppressing photochemical reactions with quantized light fields

    NASA Astrophysics Data System (ADS)

    Galego, Javier; Garcia-Vidal, Francisco J.; Feist, Johannes

    2016-12-01

    Photoisomerization, that is, a photochemical reaction leading to a change of molecular structure after absorption of a photon, can have detrimental effects such as leading to DNA damage under solar irradiation, or as a limiting factor for the efficiency of solar cells. Here, we show that strong coupling of organic molecules to a confined light mode can be used to strongly suppress photoisomerization, as well as other photochemical reactions, and thus convert molecules that normally show fast photodegradation into photostable forms. We find this to be especially efficient in the case of collective strong coupling, where the distribution of a single excitation over many molecules and the light mode leads to a collective protection effect that almost completely suppresses the photochemical reaction.

  20. Active flutter suppression using dipole filters

    NASA Technical Reports Server (NTRS)

    Srinathkumar, S.; Waszak, Martin R.

    1992-01-01

    By using traditional control concepts of gain root locus, the active suppression of a flutter mode of a flexible wing is examined. It is shown that the attraction of the unstable mode towards a critical system zero determines the degree to which the flutter mode can be stabilized. For control situations where the critical zero is adversely placed in the complex plane, a novel compensation scheme called a 'Dipole' filter is proposed. This filter ensures that the flutter mode is stabilized with acceptable control energy. The control strategy is illustrated by designing flutter suppression laws for an active flexible wing (AFW) wind-tunnel model, where minimal control effort solutions are mandated by control rate saturation problems caused by wind-tunnel turbulence.

  1. Suppressing photochemical reactions with quantized light fields

    PubMed Central

    Galego, Javier; Garcia-Vidal, Francisco J.; Feist, Johannes

    2016-01-01

    Photoisomerization, that is, a photochemical reaction leading to a change of molecular structure after absorption of a photon, can have detrimental effects such as leading to DNA damage under solar irradiation, or as a limiting factor for the efficiency of solar cells. Here, we show that strong coupling of organic molecules to a confined light mode can be used to strongly suppress photoisomerization, as well as other photochemical reactions, and thus convert molecules that normally show fast photodegradation into photostable forms. We find this to be especially efficient in the case of collective strong coupling, where the distribution of a single excitation over many molecules and the light mode leads to a collective protection effect that almost completely suppresses the photochemical reaction. PMID:27941754

  2. Sleep deprivation suppresses aggression in Drosophila

    PubMed Central

    Kayser, Matthew S; Mainwaring, Benjamin; Yue, Zhifeng; Sehgal, Amita

    2015-01-01

    Sleep disturbances negatively impact numerous functions and have been linked to aggression and violence. However, a clear effect of sleep deprivation on aggressive behaviors remains unclear. We find that acute sleep deprivation profoundly suppresses aggressive behaviors in the fruit fly, while other social behaviors are unaffected. This suppression is recovered following post-deprivation sleep rebound, and occurs regardless of the approach to achieve sleep loss. Genetic and pharmacologic approaches suggest octopamine signaling transmits changes in aggression upon sleep deprivation, and reduced aggression places sleep-deprived flies at a competitive disadvantage for obtaining a reproductive partner. These findings demonstrate an interaction between two phylogenetically conserved behaviors, and suggest that previous sleep experiences strongly modulate aggression with consequences for reproductive fitness. DOI: http://dx.doi.org/10.7554/eLife.07643.001 PMID:26216041

  3. Appetite suppressants and valvular heart disease.

    PubMed

    Seghatol, Frank F; Rigolin, Vera H

    2002-09-01

    Appetite suppressants fenfluramine, dexfenfluramine, and phentermine have been used alone or in combination as an alternative to diet and surgery in the management of obesity. This therapy was halted in 1997 after reports of valvular lesions affecting almost one third of patients treated with these drugs. Fortunately, most cases of appetite suppressant-related valve disease are mild or moderate and rarely required valve repair or replacement. Follow-up studies have suggested improvement in valvulopathy after discontinuation of the treatment. The mechanism of valve disease induced by these drugs is speculative and may be related to their serotonergic effects. Echocardiographic features are similar to carcinoid heart disease and valvulopathy associated with ergot use. Most cases require only follow-up and endocarditis prophylaxis; surgery is rarely needed.

  4. System for Suppressing Vibration in Turbomachine Components

    NASA Technical Reports Server (NTRS)

    Morrison, Carlos R. (Inventor); Provenza, Andrew J. (Inventor); Choi, Benjamin B. (Inventor); Bakhle, Milind A. (Inventor); Min, James B (Inventor); Stefko, George L. (Inventor); Kussmann, John A (Inventor); Fougere, Alan J (Inventor)

    2013-01-01

    Disclosed is a system for suppressing vibration and noise mitigation in structures such as blades in turbomachinery. The system includes flexible piezoelectric patches which are secured on or imbedded in turbomachinery blades which, in one embodiment, comprises eight (8) fan blades. The system further includes a capacitor plate coupler and a power transfer apparatus, which may both be arranged into one assembly, that respectively transfer data and power. Each of the capacitive plate coupler and power transfer apparatus is configured so that one part is attached to a fixed member while another part is attached to a rotatable member with an air gap there between. The system still further includes a processor that has 16 channels, eight of which serve as sensor channels, and the remaining eight, serving as actuation channels. The processor collects and analyzes the sensor signals and, in turn, outputs corrective signals for vibration/noise suppression of the turbine blades.

  5. Immersion diuresis without expected suppression of vasopressin

    NASA Technical Reports Server (NTRS)

    Keil, L. C.; Silver, J. E.; Wong, N.; Spaul, W. A.; Greenleaf, J. E.; Kravik, S. E.

    1984-01-01

    There is a shift of blood from the lower parts of the body to the thoracic circulation during bed rest, water immersion, and presumably during weightlessness. On earth, this central fluid shift is associated with a profound diuresis. However, the mechanism involved is not yet well understood. The present investigation is concerned with measurements regarding the plasma vasopressin, fluid, electrolyte, and plasma renin activity (PRA) responses in subjects with normal preimmersion plasma vasopressin (PVP) concentration. In the conducted experiments, PRA was suppressed significantly at 30 min of immersion and had declined by 74 percent by the end of the experiment. On the basis of previously obtained results, it appears that sodium excretion during immersion may be independent of aldosterone action. Experimental results indicate that PVP is not suppressed by water immersion in normally hydrated subjects and that other factors may be responsible for the diuresis.

  6. Abnormal Grain Growth Suppression in Aluminum Alloys

    NASA Technical Reports Server (NTRS)

    Hales, Stephen J. (Inventor); Claytor, Harold Dale (Inventor); Alexa, Joel A. (Inventor)

    2015-01-01

    The present invention provides a process for suppressing abnormal grain growth in friction stir welded aluminum alloys by inserting an intermediate annealing treatment ("IAT") after the welding step on the article. The IAT may be followed by a solution heat treatment (SHT) on the article under effectively high solution heat treatment conditions. In at least some embodiments, a deformation step is conducted on the article under effective spin-forming deformation conditions or under effective superplastic deformation conditions. The invention further provides a welded article having suppressed abnormal grain growth, prepared by the process above. Preferably the article is characterized with greater than about 90% reduction in area fraction abnormal grain growth in any friction-stir-welded nugget.

  7. Adaptive Suppression of Noise in Voice Communications

    NASA Technical Reports Server (NTRS)

    Kozel, David; DeVault, James A.; Birr, Richard B.

    2003-01-01

    A subsystem for the adaptive suppression of noise in a voice communication system effects a high level of reduction of noise that enters the system through microphones. The subsystem includes a digital signal processor (DSP) plus circuitry that implements voice-recognition and spectral- manipulation techniques. The development of the adaptive noise-suppression subsystem was prompted by the following considerations: During processing of the space shuttle at Kennedy Space Center, voice communications among test team members have been significantly impaired in several instances because some test participants have had to communicate from locations with high ambient noise levels. Ear protection for the personnel involved is commercially available and is used in such situations. However, commercially available noise-canceling microphones do not provide sufficient reduction of noise that enters through microphones and thus becomes transmitted on outbound communication links.

  8. Adaptive Modal Identification for Flutter Suppression Control

    NASA Technical Reports Server (NTRS)

    Nguyen, Nhan T.; Drew, Michael; Swei, Sean S.

    2016-01-01

    In this paper, we will develop an adaptive modal identification method for identifying the frequencies and damping of a flutter mode based on model-reference adaptive control (MRAC) and least-squares methods. The least-squares parameter estimation will achieve parameter convergence in the presence of persistent excitation whereas the MRAC parameter estimation does not guarantee parameter convergence. Two adaptive flutter suppression control approaches are developed: one based on MRAC and the other based on the least-squares method. The MRAC flutter suppression control is designed as an integral part of the parameter estimation where the feedback signal is used to estimate the modal information. On the other hand, the separation principle of control and estimation is applied to the least-squares method. The least-squares modal identification is used to perform parameter estimation.

  9. PUMA Suppresses Intestinal Tumorigenesis in Mice

    PubMed Central

    Qiu, Wei; Carson-Walter, Eleanor B.; Kuan, Shih Fan; Zhang, Lin; Yu, Jian

    2010-01-01

    Defective apoptosis contributes to tumorigenesis, although the critical molecular targets remain to be fully characterized. PUMA, a BH3-only protein essential for p53-dependent apoptosis, has been shown to suppress lymphomagenesis. In this study, we investigated the role of PUMA in intestinal tumorigenesis using two animal models. In the azoxymethane (AOM)/dextran sulfate sodium salt model, PUMA deficiency increased the multiplicity and size of colon tumors but reduced the frequency of β-catenin hotspot mutations. The absence of PUMA led to a significantly elevated incidence of precursor lesions induced by AOM. AOM was found to induce p53-dependent PUMA expression and PUMA-dependent apoptosis in the colonic crypts and stem cell compartment. Furthermore, PUMA deficiency significantly enhanced the formation of spontaneous macroadenomas and microadenomas in the distal small intestine and colon of APCMin/+ mice. These results show an essential role of PUMA-mediated apoptosis in suppressing intestinal tumorigenesis in mice. PMID:19491259

  10. Effect of weighting on time sidelobe suppression

    NASA Technical Reports Server (NTRS)

    Dicenzo, A.

    1978-01-01

    Weighting simulations in the time domain were considered to shape the time-compressed pulse waveform. The digital input radar data were 32 bit I,Q, and simulated data from a point target, imaged by a Seasat-A type system. Weighting functions tested include stepped-amplitude distributions, (with 1 through 5 steps), and the cosine-squared plus pedestal distribution. Effects treated include mainlobe ratio, signal to noise ratio, and nearest sidelobe suppression.

  11. Analysis and Evaluation of Suppressive Shields

    DTIC Science & Technology

    1977-06-01

    resistance of the shield to fragment penetration, and 7. attenuation of thermal effects by the shield . Other aspects of the design include problems of entry...propellant, 2. methods to predict the thermal environment outside of a suppressive shield , 3. comparisons between measured and predicted pressures... SHIELDS by P. A. Co- x P. S. Westine CD J. J. Kulesz L.LJ E. D. Espurza c-.- January 1978 SOUTHWEST RESEARCH INSTITUTE Post Office Drawer 28510, 6220

  12. Investigation of refracting flows for acoustic suppression

    NASA Technical Reports Server (NTRS)

    Sloan, D.; Purves, R. B.; Farquhar, B. W.

    1977-01-01

    An experimental program to determine the possibility of using refracting flows for the suppression of aircraft inlet noise has been completed. Observations of wave behavior in accelerating duct flows have suggested that acoustic wave refraction could be used to direct inlet noise away from the ground upward to where it causes less annoyance. Measurements have also shown that acoustic wave refraction can cause large improvements in the effectiveness of acoustic lining material.

  13. Currently available cough suppressants for chronic cough.

    PubMed

    Chung, Kian Fan

    2008-01-01

    Chronic cough is a common symptom but only a fraction of patients seek medical attention. Addressing the causes of chronic cough may lead to control of cough; however, this approach is not always successful since there is a certain degree of failure even when the cause(s) of cough are adequately treated; in idiopathic cough, there is no cause to treat. Persistent cough may be associated with deterioration of quality of life, and treatment with cough suppressants is indicated. Currently available cough suppressants include the centrally acting opioids such as morphine, codeine, and dextromethorphan. Peripherally acting antitussives include moguisteine and levodropropizine. Early studies report success in reducing cough in patients with chronic bronchitis or COPD; however, a carefully conducted study showed no effect of codeine on cough of COPD. Success with these cough suppressants can be achieved at high doses that are associated with side effects. Slow-release morphine has been reported to be useful in controlling intractable cough with good tolerance to constipation and drowsiness. There have been case reports of the success of centrally acting drugs such as amitryptiline, paroxetine, gabapentin, and carbamezepine in chronic cough. New opioids such as nociceptin or antagonists of TRPV1 may turn out to be more effective. Efficacy of cough suppressants must be tested in double-blind randomised trials using validated measures of cough in patients with chronic cough not responding to specific treatments. Patients with chronic cough are in desperate need of effective antitussives that can be used either on demand or on a long-term basis.

  14. [Cancer immunotherapy. Importance of overcoming immune suppression].

    PubMed

    Malvicini, Mariana; Puchulo, Guillermo; Matar, Pablo; Mazzolini, Guillermo

    2010-01-01

    Increasing evidence indicates that the immune system is involved in the control of tumor progression. Effective antitumor immune response depends on the interaction between several components of the immune system, including antigen-presenting cells and different T cell subsets. However, tumor cells develop a number of mechanisms to escape recognition and elimination by the immune system. In this review we discuss these mechanisms and address possible therapeutic approaches to overcome the immune suppression generated by tumors.

  15. Fire suppression in human-crew spacecraft

    NASA Technical Reports Server (NTRS)

    Friedman, Robert; Dietrich, Daniel L.

    1991-01-01

    Fire extinguishment agents range from water and foam in early-design spacecraft (Halon 1301 in the present Shuttle) to carbon dioxide proposed for the Space Station Freedom. The major challenge to spacecraft fire extinguishment design and operations is from the micro-gravity environment, which minimizes natural convection and profoundly influences combustion and extinguishing agent effectiveness, dispersal, and post-fire cleanup. Discussed here are extinguishment in microgravity, fire-suppression problems anticipated in future spacecraft, and research needs and opportunities.

  16. FGF Suppresses Poldip2 Expression in Osteoblasts.

    PubMed

    Katsumura, Sakie; Izu, Yayoi; Yamada, Takayuki; Griendling, Kathy; Harada, Kiyoshi; Noda, Masaki; Ezura, Yoichi

    2016-12-05

    Osteoporosis is one of the most prevalent ageing-associated diseases that are soaring in the modern world. Although various aspects of the disease have been investigated to understand the bases of osteoporosis, the pathophysiological mechanisms underlying bone loss is still incompletely understood. Poldip2 is a molecule that has been shown to be involved in cell migration of vascular cells and angiogenesis. However, expression of Poldip2 and its regulation in bone cells were not known. Therefore, we examined the Poldip2 mRNA expression and the effects of bone regulators on the Poldip2 expression in osteoblasts. We found that Poldip2 mRNA is expressed in osteoblastic MC3T3-E1 cells. As FGF controls osteoblasts and angiogenesis, FGF regulation was investigated in these cells. FGF suppressed the expression of Poldip2 in MC3T3-E1 cells in a time dependent manner. Protein synthesis inhibitor but not transcription inhibitor reduced the FGF effects on Poldip2 gene expression in MC3T3-E1 cells. As for bone-related hormones, dexamethasone was found to enhance the expression of Poldip2 in osteoblastic MC3T3-E1 cells whereas FGF still suppressed such dexamethasone effects. With respect to function, knockdown of Poldip2 by siRNA suppressed the migration of MC3T3-E1 cells. Poldip2 was also expressed in the primary cultures of osteoblast-enriched cells and FGF also suppressed its expression. Finally, Poldip2 was expressed in femoral bone in vivo and its levels were increased in aged mice compared to young adult mice. These data indicate that Poldip2 is expressed in osteoblastic cells and is one of the targets of FGF. J. Cell. Biochem. 9999: 1-8, 2017. © 2016 Wiley Periodicals, Inc.

  17. Suppression of Ostwald Ripening by Chemical Reactions

    NASA Astrophysics Data System (ADS)

    Zwicker, David; Hyman, Anthony A.; Jülicher, Frank

    2015-03-01

    Emulsions consisting of droplets immersed in a fluid are typically unstable and coarsen over time. One important coarsening process is Ostwald ripening, which is driven by the surface tension of the droplets. Ostwald ripening must thus be suppressed to stabilize emulsions, e.g. to control the properties of pharmaceuticals, food, or cosmetics. Suppression of Ostwald ripening is also important in biological cells, which contain stable liquid-like compartments, e.g. germ granules, Cajal-bodies, and centrosomes. Such systems are often driven away from equilibrium by chemical reactions and can thus be called active emulsions. Here, we show that non-equilibrium chemical reactions can suppress Ostwald Ripening, leading to stable, monodisperse emulsions. We derive analytical approximations of the typical droplet size, droplet count, and time scale of the dynamics from a coarse-grained description of the droplet dynamics. We also compare these results to numerical simulations of the continuous concentration fields. Generally, we thus show how chemical reactions can be used to stabilize emulsions and to control their properties in technology and nature.

  18. Suppressing bullfrog larvae with carbon dioxide

    USGS Publications Warehouse

    Gross, Jackson A.; Ray, Andrew; Sepulveda, Adam J.; Watten, Barnaby J.; Densmore, Christine L.; Layhee, Megan J.; Mark Abbey-Lambert,; ,

    2014-01-01

    Current management strategies for the control and suppression of the American Bullfrog (Lithobates catesbeianus = Rana catesbeiana Shaw) and other invasive amphibians have had minimal effect on their abundance and distribution. This study evaluates the effects of carbon dioxide (CO2) on pre- and prometamorphic Bullfrog larvae. Bullfrogs are a model organism for evaluating potential suppression agents because they are a successful invader worldwide. From experimental trials we estimated that the 24-h 50% and 99% lethal concentration (LC50 and LC99) values for Bullfrog larvae were 371 and 549 mg CO2/L, respectively. Overall, larvae that succumbed to experimental conditions had a lower body condition index than those that survived. We also documented sublethal changes in blood chemistry during prolonged exposure to elevated CO2. Specifically, blood pH decreased by more than 0.5 pH units after 9 h of exposure and both blood partial pressure of CO2 (pCO2) and blood glucose increased. These findings suggest that CO2 treatments can be lethal to Bullfrog larvae under controlled laboratory conditions. We believe this work represents the necessary foundation for further consideration of CO2 as a potential suppression agent for one of the most harmful invaders to freshwater ecosystems.

  19. Hypergravity suppresses bone resorption in ovariectomized rats

    NASA Astrophysics Data System (ADS)

    Ikawa, Tesshu; Kawaguchi, Amu; Okabe, Takahiro; Ninomiya, Tadashi; Nakamichi, Yuko; Nakamura, Midori; Uehara, Shunsuke; Nakamura, Hiroaki; Udagawa, Nobuyuki; Takahashi, Naoyuki; Nakamura, Hiroaki; Wakitani, Shigeyuki

    2011-04-01

    The effects of gravity on bone metabolism are unclear, and little has been reported about the effects of hypergravity on the mature skeleton. Since low gravity has been shown to decrease bone volume, we hypothesized that hypergravity increases bone volume. To clarify this hypothesis, adult female rats were ovariectomized and exposed to hypergravity (2.9G) using a centrifugation system. The rats were killed 28 days after the start of loading, and the distal femoral metaphysis of the rats was studied. Bone architecture was assessed by micro-computed tomography (micro-CT) and bone mineral density was measured using peripheral quantitative CT (pQCT). Hypergravity increased the trabecular bone volume of ovariectomized rats. Histomorphometric analyses revealed that hypergravity suppressed both bone formation and resorption and increased bone volume in ovariectomized rats. Further, the cell morphology, activity, proliferation, and differentiation of osteoclasts and osteoblasts exposed to hypergravity were evaluated in vitro. Hypergravity inhibited actin ring formation in mature osteoclasts, which suggested that the osteoclast activity was suppressed. However, hypergravity had no effect on osteoblasts. These results suggest that hypergravity can stimulate an increase in bone volume by suppressing bone resorption in ovariectomized rats.

  20. Neural Networks for Mindfulness and Emotion Suppression.

    PubMed

    Murakami, Hiroki; Katsunuma, Ruri; Oba, Kentaro; Terasawa, Yuri; Motomura, Yuki; Mishima, Kazuo; Moriguchi, Yoshiya

    2015-01-01

    Mindfulness, an attentive non-judgmental focus on "here and now" experiences, has been incorporated into various cognitive behavioral therapy approaches and beneficial effects have been demonstrated. Recently, mindfulness has also been identified as a potentially effective emotion regulation strategy. On the other hand, emotion suppression, which refers to trying to avoid or escape from experiencing and being aware of one's own emotions, has been identified as a potentially maladaptive strategy. Previous studies suggest that both strategies can decrease affective responses to emotional stimuli. They would, however, be expected to provide regulation through different top-down modulation systems. The present study was aimed at elucidating the different neural systems underlying emotion regulation via mindfulness and emotion suppression approaches. Twenty-one healthy participants used the two types of strategy in response to emotional visual stimuli while functional magnetic resonance imaging was conducted. Both strategies attenuated amygdala responses to emotional triggers, but the pathways to regulation differed across the two. A mindful approach appears to regulate amygdala functioning via functional connectivity from the medial prefrontal cortex, while suppression uses connectivity with other regions, including the dorsolateral prefrontal cortex. Thus, the two types of emotion regulation recruit different top-down modulation processes localized at prefrontal areas. These different pathways are discussed.

  1. Surface state transport suppression in topological insulators

    NASA Astrophysics Data System (ADS)

    Reijnders, Anjan A.; Tian, Y.; Pohl, G.; Kivlichan, I. D.; Zhao, S. Y. Frank; Kim, Y.-J.; Jia, S.; Cava, R. J.; Kwok, D. C.; Lee, N.; Cheong, S. W.; Burch, Kenneth S.

    2013-03-01

    An unresolved question in experimental research on topological insulators (TI) is the suppression mechanism of a TI's surface state transport. While room temperature ARPES studies reveal clear evidence of surface states, their observation in transport measurements is limited to low temperatures. A better understanding of this suppression is of fundamental interest, and crucial for pushing the boundary of device applications towards room-temperature operation. In this talk, we report the temperature dependent optical properties of the topological insulator Bi2Te2Se (BTS), obtained by infrared spectroscopy and ellipsometry, probing surface and bulk states simultaneously. We see clear evidence of coherent surface state transport at low temperature and find that electron-phonon coupling causes the gradual suppression of surface state transport as temperature rises to 43K. In the bulk, electron-phonon coupling enables the emergence of an indirect band gap transition, which peaks at 43K, and is limited by thermal ionization of the bulk valance band above 43K. For comparison with other resistive TIs, we also discuss the optical properties to BiSbSe2Te. Financially supported by NSERC CRSNG, Ontario Research Fund, Canadian Foundation for Innovation, Prins Bernhard Cultuurfonds, NSF

  2. Atomic clocks with suppressed blackbody radiation shift.

    PubMed

    Yudin, V I; Taichenachev, A V; Okhapkin, M V; Bagayev, S N; Tamm, Chr; Peik, E; Huntemann, N; Mehlstäubler, T E; Riehle, F

    2011-07-15

    We develop a concept of atomic clocks where the blackbody radiation shift and its fluctuations can be suppressed by 1-3 orders of magnitude independent of the environmental temperature. The suppression is based on the fact that in a system with two accessible clock transitions (with frequencies ν1 and ν2) which are exposed to the same thermal environment, there exists a "synthetic" frequency ν(syn) ∝ (ν1 - ε12ν2) largely immune to the blackbody radiation shift. For example, in the case of 171Yb+ it is possible to create a synthetic-frequency-based clock in which the fractional blackbody radiation shift can be suppressed to the level of 10(-18) in a broad interval near room temperature (300±15  K). We also propose a realization of our method with the use of an optical frequency comb generator stabilized to both frequencies ν1 and ν2, where the frequency ν(syn) is generated as one of the components of the comb spectrum.

  3. Hippocampal leptin suppresses methamphetamine-induced hyperlocomotion.

    PubMed

    Nishio, Masahiro; Watanabe, Yasuhiro

    2010-10-01

    Leptin is an anorexigenic peptide which is synthesized in white adipose tissue. The actions of leptin are mediated by the leptin receptor which is abundantly localized in the hypothalamus and is involved in energy regulation and balance. Recently, there has been evidence suggesting that the leptin receptor is also present in the hippocampus and may be involved with hippocampal excitability and long-term depression. To investigate the physiological function of leptin signalling in the hippocampus, we studied the effects of leptin on methamphetamine-induced ambulatory hyperactivity by utilizing intra-hippocampal infusion (i.h.) in mice. Our results show that the infusion of leptin (5 ng each bilaterally i.h.) does not affect the basal ambulatory activity but significantly suppresses methamphetamine-induced ambulatory hyperactivity as compared to saline-infused controls. Interestingly, higher dose of leptin increases the suppression of the methamphetamine-induced ambulatory hyperactivity. The i.h. infusion of leptin did not activate the JAK-STAT pathway, which is the cellular signalling pathway through which leptin acts in the hypothalamus. The infusion of leptin also did not affect activation of p42/44 MAPK which is known to be another leptin-induced signalling pathway in the brain. These results demonstrate that leptin has a novel potential suppressive effect on methamphetamine-induced hyperlocomotion and also suggest that there must be an alternative pathway in the hippocampus through which leptin signalling is being mediated.

  4. Suppression of Marangoni Convection in Float Zones

    NASA Technical Reports Server (NTRS)

    Dressler, R. F.

    1985-01-01

    The basic purpose of this program is to demonstrate by means of an Earth-based 1-g experiment that the undesirable Marangoni (surface tension) convection can be suppressed or significantly reduced by means of gas jets directed tangentially to the free surface of the liquid in a float zone. These jets will establish the tangential shear stress field over the surface which must be adjusted to equal the counter-stress resultant of the Marangoni shear stress which causes the convection. For proposed materials processing in space (o-g), particularly of important, highly reactive semiconductor materials, e.g., silicon, microgravity will virtually eliminate the unwanted thermal-buoyancy convection in the liquid silicon, but will have no effect in reducing the Marangoni convection. Unless this can be sufficiently suppressed by other means, there may be no significant advantages to the proposed space processing of reactive semiconductors. Although some inert gas such as argon must be used for the corrosive liquid silicon, the Earth-based experiment uses air jets and various transparent oils, since the basic principle involved is the same. The first float zone is enclosed in a very small rectangular box with a quasi-planar free surface. Stable Marangoni convection has been achieved and velocities measured photographically. The air jet system with variable velocity and temperature is under construction. Three independent parameters must be optimized to attain maximum suppression: the gas velocity, angle of attack, and gas temperature.

  5. Glucocorticoids suppress bone formation via the osteoclast.

    PubMed

    Kim, Hyun-Ju; Zhao, Haibo; Kitaura, Hideki; Bhattacharyya, Sandip; Brewer, Judson A; Muglia, Louis J; Ross, F Patrick; Teitelbaum, Steven L

    2006-08-01

    The pathogenesis of glucocorticoid-induced (GC-induced) bone loss is unclear. For example, osteoblast apoptosis is enhanced by GCs in vivo, but they stimulate bone formation in vitro. This conundrum suggests that an intermediary cell transmits a component of the bone-suppressive effects of GCs to osteoblasts in the intact animal. Bone remodeling is characterized by tethering of the activities of osteoclasts and osteoblasts. Hence, the osteoclast is a potential modulator of the effect of GCs on osteoblasts. To define the direct impact of GCs on bone-resorptive cells, we compared the effects of dexamethasone (DEX) on WT osteoclasts with those derived from mice with disruption of the GC receptor in osteoclast lineage cells (GRoc-/- mice). While the steroid prolonged longevity of osteoclasts, their bone-degrading capacity was suppressed. The inhibitory effect of DEX on bone resorption reflects failure of osteoclasts to organize their cytoskeleton in response to M-CSF. DEX specifically arrested M-CSF activation of RhoA, Rac, and Vav3, each of which regulate the osteoclast cytoskeleton. In all circumstances GRoc-/- mice were spared the impact of DEX on osteoclasts and their precursors. Consistent with osteoclasts modulating the osteoblast-suppressive effect of DEX, GRoc-/- mice are protected from the steroid's inhibition of bone formation.

  6. Conditionals, Context, and the Suppression Effect.

    PubMed

    Cariani, Fabrizio; Rips, Lance J

    2016-02-01

    Modus ponens is the argument from premises of the form If A, then B and A to the conclusion B (e.g., from If it rained, Alicia got wet and It rained to Alicia got wet). Nearly all participants agree that the modus ponens conclusion logically follows when the argument appears in this Basic form. However, adding a further premise (e.g., If she forgot her umbrella, Alicia got wet) can lower participants' rate of agreement-an effect called suppression. We propose a theory of suppression that draws on contemporary ideas about conditional sentences in linguistics and philosophy. Semantically, the theory assumes that people interpret an indicative conditional as a context-sensitive strict conditional: true if and only if its consequent is true in each of a contextually determined set of situations in which its antecedent is true. Pragmatically, the theory claims that context changes in response to new assertions, including new conditional premises. Thus, the conclusion of a modus ponens argument may no longer be accepted in the changed context. Psychologically, the theory describes people as capable of reasoning about broad classes of possible situations, ordered by typicality, without having to reason about individual possible worlds. The theory accounts for the main suppression phenomena, and it generates some novel predictions that new experiments confirm.

  7. BAER suppression during posterior fossa dural opening

    PubMed Central

    Shields, Christopher B.; Shields, Lisa B. E.; Jiang, Yi Dan; Yao, Tom; Zhang, Yi Ping; Sun, David A.

    2015-01-01

    Background: Intraoperative monitoring with brainstem auditory evoked responses (BAER) provides an early warning signal of potential neurological injury and may avert tissue damage to the auditory pathway or brainstem. Unexplained loss of the BAER signal in the operating room may present a dilemma to the neurosurgeon. Methods: This paper documents two patients who displayed a unique mechanism of suppression of the BAER apparent within minutes following dural opening for resection of a posterior fossa meningioma. Results: In two patients with anterior cerebellopontine angle and clival meningiomas, there was a significant deterioration of the BAER soon after durotomy but prior to cerebellar retraction and tumor removal. Intracranial structures in the posterior fossa lying between the tumor and dural opening were shifted posteriorly after durotomy. Conclusion: We hypothesized that the cochlear nerve and vessels entering the acoustic meatus were compressed or stretched when subjected to tissue shift. This movement caused cochlear nerve dysfunction that resulted in BAER suppression. BAER was partially restored after the tumor was decompressed, dura repaired, and bone replaced. BAER was not suppressed following durotomy for removal of a meningioma lying posterior to the cochlear complex. Insight into the mechanisms of durotomy-induced BAER inhibition would allay the neurosurgeon's anxiety during the operation. PMID:25883849

  8. System and method for suppressing sublimation using opacified aerogel

    NASA Technical Reports Server (NTRS)

    Sakamoto, Jeff S. (Inventor); Snyder, G. Jeffrey (Inventor); Calliat, Thierry (Inventor); Fleurial, Jean-Pierre (Inventor); Jones, Steven M. (Inventor); Palk, Jong-Ah (Inventor)

    2008-01-01

    The present invention relates to a castable, aerogel-based, ultra-low thermal conductivity opacified insulation to suppress sublimation. More specifically, the present invention relates to an aerogel opacified with various opacifying or reflecting constituents to suppress sublimation and provide thermal insulation in thermoelectric modules. The opacifying constituent can be graded within the aerogel for increased sublimation suppression, and the density of the aerogel can similarly be graded to achieve optimal thermal insulation and sublimation suppression.

  9. Coating Thermoelectric Devices To Suppress Sublimation

    NASA Technical Reports Server (NTRS)

    Sakamoto, Jeffrey; Caillat, Thierry; Fleurial, Jean-Pierre; Snyder, G. Jeffrey

    2007-01-01

    A technique for suppressing sublimation of key elements from skutterudite compounds in advanced thermoelectric devices has been demonstrated. The essence of the technique is to cover what would otherwise be the exposed skutterudite surface of such a device with a thin, continuous film of a chemically and physically compatible metal. Although similar to other sublimation-suppression techniques, this technique has been specifically tailored for application to skutterudite antimonides. The primary cause of deterioration of most thermoelectric materials is thermal decomposition or sublimation - one or more elements sublime from the hot side of a thermoelectric couple, changing the stoichiometry of the device. Examples of elements that sublime from their respective thermoelectric materials are Ge from SiGe, Te from Pb/Te, and now Sb from skutterudite antimonides. The skutterudite antimonides of primary interest are CoSb3 [electron-donor (n) type] and CeFe(3-x)Co(x)Sb12 [electron-acceptor (p) type]. When these compounds are subjected to typical operating conditions [temperature of 700 C and pressure <10(exp -5) torr (0.0013 Pa)], Sb sublimes from their surfaces, with the result that Sb depletion layers form and advance toward their interiors. As the depletion layer advances in a given device, the change in stoichiometry diminishes the thermal-to-electric conversion efficiency of the device. The problem, then, is to prevent sublimation, or at least reduce it to an acceptably low level. In preparation for an experiment on suppression of sublimation, a specimen of CoSb3 was tightly wrapped in a foil of niobium, which was selected for its chemical stability. In the experiment, the wrapped specimen was heated to a temperature of 700 C in a vacuum of residual pressure <10(exp -5) torr (0.0013 Pa), then cooled and sectioned. Examination of the sectioned specimen revealed that no depletion layer had formed, indicating the niobium foil prevented sublimation of antimony at 700 C

  10. Unsuppressible Repetition Suppression and exemplar-specific Expectation Suppression in the Fusiform Face Area.

    PubMed

    Pajani, Auréliane; Kouider, Sid; Roux, Paul; de Gardelle, Vincent

    2017-12-01

    Recent work casts Repetition Suppression (RS), i.e. the reduced neural response to repeated stimuli, as the consequence of reduced surprise for repeated inputs. This research, along with other studies documenting Expectation Suppression, i.e. reduced responses to expected stimuli, emphasizes the role of expectations and predictive codes in perception. Here, we use fMRI to further characterize the nature of predictive signals in the human brain. Prior to scanning, participants were implicitly exposed to associations within face pairs. Critically, we found that this resulted in exemplar-specific Expectation Suppression in the fusiform face-sensitive area (FFA): individual faces that could be predicted from the associations elicited reduced FFA responses, as compared to unpredictable faces. Thus, predictive signals in the FFA are specific to face exemplars, and not only generic to the category of face stimuli. In addition, we show that under such circumstances, the occurrence of surprising repetitions did not trigger enhanced brain responses, as had been recently hypothesized, but still suppressed responses, suggesting that repetition suppression might be partly 'unsuppressible'. Repetition effects cannot be fully modulated by expectations, which supports the recent view that expectation and repetition effects rest on partially independent mechanisms. Altogether, our study sheds light on the nature of expectation signals along the perceptual system.

  11. Repetition suppression and expectation suppression are dissociable in time in early auditory evoked fields.

    PubMed

    Todorovic, Ana; de Lange, Floris P

    2012-09-26

    Repetition of a stimulus, as well as valid expectation that a stimulus will occur, both attenuate the neural response to it. These effects, repetition suppression and expectation suppression, are typically confounded in paradigms in which the nonrepeated stimulus is also relatively rare (e.g., in oddball blocks of mismatch negativity paradigms, or in repetition suppression paradigms with multiple repetitions before an alternation). However, recent hierarchical models of sensory processing inspire the hypothesis that the two might be separable in time, with repetition suppression occurring earlier, as a consequence of local transition probabilities, and suppression by expectation occurring later, as a consequence of learnt statistical regularities. Here we test this hypothesis in an auditory experiment by orthogonally manipulating stimulus repetition and stimulus expectation and, using magnetoencephalography, measuring the neural response over time in human subjects. We found that stimulus repetition (but not stimulus expectation) attenuates the early auditory response (40-60 ms), while stimulus expectation (but not stimulus repetition) attenuates the subsequent, intermediate stage of auditory processing (100-200 ms). These findings are well in line with hierarchical predictive coding models, which posit sequential stages of prediction error resolution, contingent on the level at which the hypothesis is generated.

  12. Individual Differences in Spontaneous Expressive Suppression Predict Amygdala Responses to Fearful Stimuli: The Role of Suppression Priming

    PubMed Central

    Chen, Shengdong; Deng, Zhongyan; Xu, Yin; Long, Quanshan; Yang, Jiemin; Yuan, Jiajin

    2017-01-01

    Though the spontaneous emotion regulation has received long discussions, few studies have explored the regulatory effects of spontaneous expressive suppression in neural activations, especially in collectivistic cultural context. The functional magnetic resonance imaging (fMRI) study aimed to examine whether individual differences in the tendency to use suppression are correlated with amygdala responses to negative situations when individuals are unconsciously primed with expressive suppression. Twenty-three healthy Chinese undergraduates completed an fMRI paradigm involving fear processing, and a synonym matching task was added to prime participants with the unconscious (automatic) expressive suppression goal. Participants completed measures of typical emotion regulation use (reappraisal and suppression), trait anxiety, and neuroticism. Results indicated that only in emotion suppression prime condition, greater use of suppression in everyday life was related to decreased amygdala activity. These associations were not attributable to variation in trait anxiety, neuroticism, or the habitual use of reappraisal. These findings suggest that in collectivistic cultural settings, individual differences in expressive suppression do not alter fear-related neural activation during suppression-irrelevant context. However, unconscious suppression priming facilitates the manifestation of individual differences in the neural consequence of expressive suppression, as reflected by the priming-specific decrease of emotional subcortical activations with more use of expressive suppression. PMID:28197108

  13. UAV visual signature suppression via adaptive materials

    NASA Astrophysics Data System (ADS)

    Barrett, Ron; Melkert, Joris

    2005-05-01

    Visual signature suppression (VSS) methods for several classes of aircraft from WWII on are examined and historically summarized. This study shows that for some classes of uninhabited aerial vehicles (UAVs), primary mission threats do not stem from infrared or radar signatures, but from the amount that an aircraft visually stands out against the sky. The paper shows that such visual mismatch can often jeopardize mission success and/or induce the destruction of the entire aircraft. A psycho-physioptical study was conducted to establish the definition and benchmarks of a Visual Cross Section (VCS) for airborne objects. This study was centered on combining the effects of size, shape, color and luminosity or effective illumance (EI) of a given aircraft to arrive at a VCS. A series of tests were conducted with a 6.6ft (2m) UAV which was fitted with optically adaptive electroluminescent sheets at altitudes of up to 1000 ft (300m). It was shown that with proper tailoring of the color and luminosity, the VCS of the aircraft dropped from more than 4,200cm2 to less than 1.8cm2 at 100m (the observed lower limit of the 20-20 human eye in this study). In laypersons terms this indicated that the UAV essentially "disappeared". This study concludes with an assessment of the weight and volume impact of such a Visual Suppression System (VSS) on the UAV, showing that VCS levels on this class UAV can be suppressed to below 1.8cm2 for aircraft gross weight penalties of only 9.8%.

  14. Revisiting mu suppression in autism spectrum disorder.

    PubMed

    Dumas, Guillaume; Soussignan, Robert; Hugueville, Laurent; Martinerie, Jacques; Nadel, Jacqueline

    2014-10-17

    Two aspects of the EEG literature lead us to revisit mu suppression in Autism Spectrum Disorder (ASD). First and despite the fact that the mu rhythm can be functionally segregated in two discrete sub-bands, 8-10 Hz and 10-12/13 Hz, mu-suppression in ASD has been analyzed as a homogeneous phenomenon covering the 8-13 Hz frequency. Second and although alpha-like activity is usually found across the entire scalp, ASD studies of action observation have focused on the central electrodes (C3/C4). The present study was aimed at testing on the whole brain the hypothesis of a functional dissociation of mu and alpha responses to the observation of human actions in ASD according to bandwidths. Electroencephalographic (EEG) mu and alpha responses to execution and observation of hand gestures were recorded on the whole scalp in high functioning subjects with ASD and typical subjects. When two bandwidths of the alpha-mu 8-13 Hz were distinguished, a different mu response to observation appeared for subjects with ASD in the upper sub-band over the sensorimotor cortex, whilst the lower sub-band responded similarly in the two groups. Source reconstructions demonstrated that this effect was related to a joint mu-suppression deficit over the occipito-parietal regions and an increase over the frontal regions. These findings suggest peculiarities in top-down response modulation in ASD and question the claim of a global dysfunction of the MNS in autism. This research also advocates for the use of finer grained analyses at both spatial and spectral levels for future directions in neurophysiological accounts of autism.

  15. Cough Suppressant and Pharmacologic Protussive Therapy

    PubMed Central

    Bolser, Donald C.

    2011-01-01

    Background Cough-suppressant therapy, previously termed nonspecific antitussive therapy, incorporates the use of pharmacologic agents with mucolytic effects and/or inhibitory effects on the cough reflex itself. The intent of this type of therapy is to reduce the frequency and/or intensity of coughing on a short-term basis. Methods Data for this review were obtained from several National Library of Medicine (PubMed) searches (from 1960 to 2004), which were performed between May and September 2004, of the literature published in the English language, limited to human studies, using combinations of the search terms “cough,” “double-blind placebo-controlled,” “antitussive,” “mucolytic,” “cough clearance,” “common cold,” “protussive,” “guaifenesin,” “glycerol,” and “zinc.” Results Mucolytic agents are not consistently effective in ameliorating cough in patients with bronchitis, although they may be of benefit to this population in other ways. Peripheral and central antitussive agents can be useful in patients with chronic bronchitis, but can have little efficacy in patients with cough due to upper respiratory infection. Some protussive agents are effective in increasing cough clearance, but their long-term effectiveness has not been established. DNase is not effective as a protussive agent in patients with cystic fibrosis. Inhaled mannitol is acutely effective in this patient population, but its therapeutic potential must be investigated further. Conclusions These findings suggest that suppressant therapy is most effective when used for the short-term reduction of coughing. Relatively few drugs are effective as cough suppressants. PMID:16428717

  16. Weed Suppression by Seven Clover Species

    SciTech Connect

    Ross, Shirley M.; King, Jane R.; Izaurralde, R Cesar C.; O'Donovan, John T.

    2001-01-01

    Used as cover crops, clover species may differ in their ability to suppress weed growth. Field trials were conducted in Alberta, Canada to measure the growth of brown mustard [Brassica juncea (L.) Czern.], in mowed and nonmowed production, as influenced by alsike (Trifolium hybridum L.), balansa [T. michelianum Savi var. balansae (Boiss.) Azn.], berseem (T. alexandrinum L.), crimson [T. incarnatum (Boiss.) Azn.], berseem (T. alexandrinum L.), crimson (T. incarnatum L.), Persian (T. resupinatum L.), red (T. pratense L.), and white Dutch (T. repens L.) clover and fall rye (Secale cereale L.). In 1997, clovers reduced mustard biomass in nonmowed treatments by 29% on a high- fertility soil (Typic Cryoboroll) at Edmonton and by 57% on a low- fertility soil (Typic Cryoboralf) at Breton. At Edmonton, nonmowed mustard biomass was reduced by alsike and berseem clover in 1996 and by alsike, balansa, berseem, and crimson clover in 1997. At Breton, all seven clover species suppressed weed biomass. A negative correlation was noted among clover and mustard biomass at Edmonton but not at Breton. The effects of mowing varied with location, timing, and species. Mowing was beneficial to crop/weed proportion at Edmonton but not at Breton. Mowing at early flowering of mustard large-seeded legumes and sweetclover (Melilotus offici) produced greater benefit than mowing at late flowering. With early mowing, all clover species suppressed mustard growth at Edmonton. Clovers reduced mustard regrowth (g plant21 ) and the number of mustard plants producing regrowth. The characteristics of berseem clover (upright growth, long stems, high biomass, and late flowering) would support its use as a cover crop or forage in north-central Alberta.

  17. Suppression of erythropoiesis by dietary nitrate

    PubMed Central

    Ashmore, Tom; Fernandez, Bernadette O.; Evans, Colin E.; Huang, Yun; Branco-Price, Cristina; Griffin, Julian L.; Johnson, Randall S.; Feelisch, Martin; Murray, Andrew J.

    2015-01-01

    In mammals, hypoxia-triggered erythropoietin release increases red blood cell mass to meet tissue oxygen demands. Using male Wistar rats, we unmask a previously unrecognized regulatory pathway of erythropoiesis involving suppressor control by the NO metabolite and ubiquitous dietary component nitrate. We find that circulating hemoglobin levels are modulated by nitrate at concentrations achievable by dietary intervention under normoxic and hypoxic conditions; a moderate dose of nitrate administered via the drinking water (7 mg NaNO3/kg body weight/d) lowered hemoglobin concentration and hematocrit after 6 d compared with nonsupplemented/NaCl-supplemented controls. The underlying mechanism is suppression of hepatic erythropoietin expression associated with the downregulation of tissue hypoxia markers, suggesting increased pO2. At higher nitrate doses, however, a partial reversal of this effect occurred; this was accompanied by increased renal erythropoietin expression and stabilization of hypoxia-inducible factors, likely brought about by the relative anemia. Thus, hepatic and renal hypoxia-sensing pathways act in concert to modulate hemoglobin in response to nitrate, converging at an optimal minimal hemoglobin concentration appropriate to the environmental/physiologic situation. Suppression of hepatic erythropoietin expression by nitrate may thus act to decrease blood viscosity while matching oxygen supply to demand, whereas renal oxygen sensing could act as a brake, averting a potentially detrimental fall in hematocrit.—Ashmore, T., Fernandez, B. O., Evans, C. E., Huang, Y., Branco-Price, C., Griffin, J. L., Johnson, R. S., Feelisch, M., Murray, A. J. Suppression of erythropoiesis by dietary nitrate. PMID:25422368

  18. Chaos suppression in gas-solid fluidization.

    PubMed

    Pence, Deborah V.; Beasley, Donald E.

    1998-06-01

    Fluidization in granular materials occurs primarily as a result of a dynamic balance between gravitational forces and forces resulting from the flow of a fluid through a bed of discrete particles. For systems where the fluidizing medium and the particles have significantly different densities, density wave instabilities create local pockets of very high void fraction termed bubbles. The fluidization regime is termed the bubbling regime. Such a system is appropriately termed a self-excited nonlinear system. The present study examines chaos suppression resulting from an opposing oscillatory flow in gas-solid fluidization. Time series data representing local, instantaneous pressure were acquired at the surface of a horizontal cylinder submerged in a bubbling fluidized bed. The particles had a weight mean diameter of 345 &mgr;m and a narrow size distribution. The state of fluidization corresponded to the bubbling regime and total air flow rates employed in the present study ranged from 10% to 40% greater than that required for minimum fluidization. The behavior of time-varying local pressure in fluidized beds in the absence of a secondary flow is consistent with deterministic chaos. Kolmogorov entropy estimates from local, instantaneous pressure suggest that the degree of chaotic behavior can be substantially suppressed by the presence of an opposing, oscillatory secondary flow. Pressure signals clearly show a "phase-locking" phenomenon coincident with the imposed frequency. In the present study, the greatest degree of suppression occurred for operating conditions with low primary and secondary flow rates, and a secondary flow oscillation frequency of 15 Hz. (c) 1998 American Institute of Physics.

  19. Cosmic Coincidences: Investigations for Neutron Background Suppression

    PubMed Central

    Heimbach, Craig R.

    2007-01-01

    Two experimental investigations were made in order to reduce background counts in neutron detectors. Each investigation relied upon the fact that neutron background is largely due to cosmic ray interactions with the air and ground. The first attempt was to look at neutron arrival times. Neutron events close in time were taken to have been of a common origin due to cosmic rays. The second investigation was similar, but based on coincident neutron/muon events. The investigations showed only a small effect, not practical for the suppression of neutron background. PMID:27110457

  20. Cosmic Coincidences: Investigations for Neutron Background Suppression.

    PubMed

    Heimbach, Craig R

    2007-01-01

    Two experimental investigations were made in order to reduce background counts in neutron detectors. Each investigation relied upon the fact that neutron background is largely due to cosmic ray interactions with the air and ground. The first attempt was to look at neutron arrival times. Neutron events close in time were taken to have been of a common origin due to cosmic rays. The second investigation was similar, but based on coincident neutron/muon events. The investigations showed only a small effect, not practical for the suppression of neutron background.

  1. Suppression of range sidelobes in bistatic radars

    NASA Astrophysics Data System (ADS)

    McCue, J. J. G.

    1980-03-01

    A bistatic radar is considered in which linear-FM pulses are employed to obtain the needed range resolution while using a long pulse. Range sidelobes of the pulse received over the direct path from the transmitter tend to interfere with the return from the target. It is shown that conventional weighting schemes give little or no suppression of some of the range sidelobes of a linear-FM rectangular pulse passed through a matched filter. This is explained by the irregular spacing of the sidelobes in the pulse when it passes through the matched filter.

  2. Suppressed $B_s$ decays at CDF

    SciTech Connect

    Dorigo, Mirco

    2011-05-01

    We review three recent results of the CDF collaboration on B{sub s}{sup 0} suppressed decays: the first search for CP-violation in the B{sub s}{sup 0} {yields} {phi}{phi} decay, where two CP-violating asymmetries expected to be zero in the Standard Model are measured, and the observation and the branching ratio measurements of B{sub s}{sup 0} {yields} J/{Psi} f{sub 0}(980) and B{sub s}{sup 0} {yields} J/{Psi} K{sup (*)} decays.

  3. Method for suppressing noise in measurements

    NASA Technical Reports Server (NTRS)

    Carson, Paul J. (Inventor); Madsen, Louis A. (Inventor); Leskowitz, Garett M. (Inventor); Weitekamp, Daniel P. (Inventor)

    2000-01-01

    Techniques of combining separate but correlated measurements to form a second-order or higher order correlation function to suppress the effects of noise in the initial condition of a system capable of retaining memory of an initial state of the system with a characteristic relaxation time. At least two separate measurements are obtained from the system. The temporal separation between the two separate measurements is preferably comparable to or less than the characteristic relaxation time and is adjusted to allow for a correlation between two measurements.

  4. Suppressing Electron Cloud in Future Linear Colliders

    SciTech Connect

    Pivi, M; Kirby, R.E.; Raubenheimer, T.O.; Le Pimpec, F.; /PSI, Villigen

    2005-05-27

    Any accelerator circulating positively charged beams can suffer from a build-up of an electron cloud (EC) in the beam pipe. The cloud develops through ionization of residual gases, synchrotron radiation and secondary electron emission and, when severe, can cause instability, emittance blow-up or loss of the circulating beam. The electron cloud is potentially a luminosity limiting effect for both the Large Hadron Collider (LHC) and the International Linear Collider (ILC). For the ILC positron damping ring, the development of the electron cloud must be suppressed. This paper discusses the state-of-the-art of the ongoing SLAC and international R&D program to study potential remedies.

  5. Orientation-tuned surround suppression in mouse visual cortex.

    PubMed

    Self, Matthew W; Lorteije, Jeannette A M; Vangeneugden, Joris; van Beest, Enny H; Grigore, Mihaela E; Levelt, Christiaan N; Heimel, J Alexander; Roelfsema, Pieter R

    2014-07-09

    The firing rates of neurons in primary visual cortex (V1) are suppressed by large stimuli, an effect known as surround suppression. In cats and monkeys, the strength of suppression is sensitive to orientation; responses to regions containing uniform orientations are more suppressed than those containing orientation contrast. This effect is thought to be important for scene segmentation, but the underlying neural mechanisms are poorly understood. We asked whether it is possible to study these mechanisms in the visual cortex of mice, because of recent advances in technology for studying the cortical circuitry in mice. It is unknown whether neurons in mouse V1 are sensitive to orientation contrast. We measured the orientation selectivity of surround suppression in the different layers of mouse V1. We found strong surround suppression in layer 4 and the superficial layers, part of which was orientation tuned: iso-oriented surrounds caused more suppression than cross-oriented surrounds. Surround suppression was delayed relative to the visual response and orientation-tuned suppression was delayed further, suggesting two separate suppressive mechanisms. Previous studies proposed that surround suppression depends on the activity of inhibitory somatostatin-positive interneurons in the superficial layers. To test the involvement of the superficial layers we topically applied lidocaine. Silencing of the superficial layers did not prevent orientation-tuned suppression in layer 4. These results show that neurons in mouse V1, which lacks orientation columns, show orientation-dependent surround suppression in layer 4 and the superficial layers and that surround suppression in layer 4 does not require contributions from neurons in the superficial layers.

  6. Suppression of Ostwald ripening in active emulsions

    NASA Astrophysics Data System (ADS)

    Zwicker, David; Hyman, Anthony A.; Jülicher, Frank

    2015-07-01

    Emulsions consisting of droplets immersed in a fluid are typically unstable since they coarsen over time. One important coarsening process is Ostwald ripening, which is driven by the surface tension of the droplets. Stability of emulsions is relevant not only in complex fluids but also in biological cells, which contain liquidlike compartments, e.g., germ granules, Cajal bodies, and centrosomes. Such cellular systems are driven away from equilibrium, e.g., by chemical reactions, and thus can be called active emulsions. In this paper, we study such active emulsions by developing a coarse-grained description of the droplet dynamics, which we analyze for two different chemical reaction schemes. We first consider the simple case of first-order reactions, which leads to stable, monodisperse emulsions in which Ostwald ripening is suppressed within a range of chemical reaction rates. We then consider autocatalytic droplets, which catalyze the production of their own droplet material. Spontaneous nucleation of autocatalytic droplets is strongly suppressed and their emulsions are typically unstable. We show that autocatalytic droplets can be nucleated reliably and their emulsions stabilized by the help of chemically active cores, which catalyze the production of droplet material. In summary, different reaction schemes and catalytic cores can be used to stabilize emulsions and to control their properties.

  7. Jet noise suppression by porous plug nozzles

    NASA Technical Reports Server (NTRS)

    Bauer, A. B.; Kibens, V.; Wlezien, R. W.

    1982-01-01

    Jet noise suppression data presented earlier by Maestrello for porous plug nozzles were supplemented by the testing of a family of nozzles having an equivalent throat diameter of 11.77 cm. Two circular reference nozzles and eight plug nozzles having radius ratios of either 0.53 or 0.80 were tested at total pressure ratios of 1.60 to 4.00. Data were taken both with and without a forward motion or coannular flow jet, and some tests were made with a heated jet. Jet thrust was measured. The data were analyzed to show the effects of suppressor geometry on nozzle propulsive efficiency and jet noise. Aerodynamic testing of the nozzles was carried out in order to study the physical features that lead to the noise suppression. The aerodynamic flow phenomena were examined by the use of high speed shadowgraph cinematography, still shadowgraphs, extensive static pressure probe measurements, and two component laser Doppler velocimeter studies. The different measurement techniques correlated well with each other and demonstrated that the porous plug changes the shock cell structure of a standard nozzle into a series of smaller, periodic cell structures without strong shock waves. These structures become smaller in dimension and have reduced pressure variations as either the plug diameter or the porosity is increased, changes that also reduce the jet noise and decrease thrust efficiency.

  8. Inhibition of saccades elicits attentional suppression.

    PubMed

    Dhawan, Saurabh; Deubel, Heiner; Jonikaitis, Donatas

    2013-05-17

    Visuospatial attention has been shown to have a central role in planning and generation of saccades but what role, if any, it plays in inhibition of saccades remains unclear. In this study, we used an oculomotor delayed match- or nonmatch-to-sample task in which a cued location has to be encoded and memorized for one of two very different goals-to plan a saccade to it or to avoid making a saccade to it. We measured the spatial allocation of attention during the delay and found that while marking a location as a future saccade target resulted in an attentional benefit at that location, marking it as forbidden to saccades led to an attentional cost. Additionally, saccade trajectories were found to deviate away more from the "don't look" location than from a saccade-irrelevant distractor confirming greater inhibition of an actively forbidden location in oculomotor programming. Our finding that attention is suppressed at locations forbidden to saccades confirms and complements the claim of a selective and obligatory coupling between saccades and attention-saccades at the memorized location could neither be planned nor suppressed independent of a corresponding effect on attentional performance.

  9. Suppression of erythropoiesis by dietary nitrate.

    PubMed

    Ashmore, Tom; Fernandez, Bernadette O; Evans, Colin E; Huang, Yun; Branco-Price, Cristina; Griffin, Julian L; Johnson, Randall S; Feelisch, Martin; Murray, Andrew J

    2015-03-01

    In mammals, hypoxia-triggered erythropoietin release increases red blood cell mass to meet tissue oxygen demands. Using male Wistar rats, we unmask a previously unrecognized regulatory pathway of erythropoiesis involving suppressor control by the NO metabolite and ubiquitous dietary component nitrate. We find that circulating hemoglobin levels are modulated by nitrate at concentrations achievable by dietary intervention under normoxic and hypoxic conditions; a moderate dose of nitrate administered via the drinking water (7 mg NaNO3/kg body weight/d) lowered hemoglobin concentration and hematocrit after 6 d compared with nonsupplemented/NaCl-supplemented controls. The underlying mechanism is suppression of hepatic erythropoietin expression associated with the downregulation of tissue hypoxia markers, suggesting increased pO2. At higher nitrate doses, however, a partial reversal of this effect occurred; this was accompanied by increased renal erythropoietin expression and stabilization of hypoxia-inducible factors, likely brought about by the relative anemia. Thus, hepatic and renal hypoxia-sensing pathways act in concert to modulate hemoglobin in response to nitrate, converging at an optimal minimal hemoglobin concentration appropriate to the environmental/physiologic situation. Suppression of hepatic erythropoietin expression by nitrate may thus act to decrease blood viscosity while matching oxygen supply to demand, whereas renal oxygen sensing could act as a brake, averting a potentially detrimental fall in hematocrit.

  10. Antisense RNA suppression of peroxidase gene expression

    SciTech Connect

    Lagrimini, L.M.; Bradford, S.; De Leon, F.D. )

    1989-04-01

    The 5{prime} half the anionic peroxidase cDNA of tobacco was inserted into a CaMV 35S promoter/terminator expression cassette in the antisense configuration. This was inserted into the Agrobacterium-mediated plant transformation vector pCIBIO which includes kanamycin selection, transformed into two species of tobacco (N. tabacum and M. sylvestris), and plants were subsequently regenerated on kanamycin. Transgenic plants were analyzed for peroxidase expression and found to have 3-5 fold lower levels of peroxidase than wild-type plants. Isoelectric focusing demonstrated that the antisense RNA only suppressed the anionic peroxidase. Wound-induced peroxidase expression was found not to be affected by the antisense RNA. Northern blots show a greater than 5 fold suppression of anionic peroxidase mRNA in leaf tissue, and the antisense RNA was expressed at a level 2 fold over the endogenous mRNA. Plants were self-pollinated and F1 plants showed normal segregation. N. sylvestris transgenic plants with the lowest level of peroxidase are epinastic, and preliminary results indicate elevated auxin levels. Excised pith tissue from both species of transgenic plants rapidly collapse when exposed to air, while pith tissue from wild-type plants showed little change when exposed to air. Further characterization of these phenotypes is currently being made.

  11. Phase noise suppression through parametric filtering

    NASA Astrophysics Data System (ADS)

    Cassella, Cristian; Strachan, Scott; Shaw, Steven W.; Piazza, Gianluca

    2017-02-01

    In this work, we introduce and experimentally demonstrate a parametric phase noise suppression technique, which we call "parametric phase noise filtering." This technique is based on the use of a solid-state parametric amplifier operating in its instability region and included in a non-autonomous feedback loop connected at the output of a noisy oscillator. We demonstrate that such a system behaves as a parametrically driven Duffing resonator and can operate at special points where it becomes largely immune to the phase fluctuations that affect the oscillator output signal. A prototype of a parametric phase noise filter (PFIL) was designed and fabricated to operate in the very-high-frequency range. The PFIL prototype allowed us to significantly reduce the phase noise at the output of a commercial signal generator operating around 220 MHz. Noise reduction of 16 dB (40×) and 13 dB (20×) were obtained, respectively, at 1 and 10 kHz offsets from the carrier frequency. The demonstration of this phase noise suppression technique opens up scenarios in the development of passive and low-cost phase noise cancellation circuits for any application demanding high quality frequency generation.

  12. Inhibition of SIRT2 suppresses hepatic fibrosis.

    PubMed

    Arteaga, Maribel; Shang, Na; Ding, Xianzhong; Yong, Sherri; Cotler, Scott J; Denning, Mitchell F; Shimamura, Takashi; Breslin, Peter; Lüscher, Bernhard; Qiu, Wei

    2016-06-01

    Liver fibrosis can progress to cirrhosis and result in serious complications of liver disease. The pathogenesis of liver fibrosis involves the activation of hepatic stellate cells (HSCs), the underlying mechanisms of which are not fully known. Emerging evidence suggests that the classic histone deacetylases play a role in liver fibrosis, but the role of another subfamily of histone deacetylases, the sirtuins, in the development of hepatic fibrosis remains unknown. In this study, we found that blocking the activity of sirtuin 2 (SIRT2) by using inhibitors or shRNAs significantly suppressed fibrogenic gene expression in HSCs. We further demonstrated that inhibition of SIRT2 results in the degradation of c-MYC, which is important for HSC activation. In addition, we discovered that inhibition of SIRT2 suppresses the phosphorylation of ERK, which is critical for the stabilization of c-MYC. Moreover, we found that Sirt2 deficiency attenuates the hepatic fibrosis induced by carbon tetrachloride (CCl4) and thioacetamide (TAA). Furthermore, we showed that SIRT2, p-ERK, and c-MYC proteins are all overexpressed in human hepatic fibrotic tissues. These data suggest a critical role for the SIRT2/ERK/c-MYC axis in promoting hepatic fibrogenesis. Inhibition of the SIRT2/ERK/c-MYC axis represents a novel strategy to prevent and to potentially treat liver fibrosis and cirrhosis.

  13. Suppression of soil nitrification by plants.

    PubMed

    Subbarao, Guntur Venkata; Yoshihashi, Tadashi; Worthington, Margaret; Nakahara, Kazuhiko; Ando, Yasuo; Sahrawat, Kanwar Lal; Rao, Idupulapati Madhusudhana; Lata, Jean-Christophe; Kishii, Masahiro; Braun, Hans-Joachim

    2015-04-01

    Nitrification, the biological oxidation of ammonium to nitrate, weakens the soil's ability to retain N and facilitates N-losses from production agriculture through nitrate-leaching and denitrification. This process has a profound influence on what form of mineral-N is absorbed, used by plants, and retained in the soil, or lost to the environment, which in turn affects N-cycling, N-use efficiency (NUE) and ecosystem health and services. As reactive-N is often the most limiting in natural ecosystems, plants have acquired a range of mechanisms that suppress soil-nitrifier activity to limit N-losses via N-leaching and denitrification. Plants' ability to produce and release nitrification inhibitors from roots and suppress soil-nitrifier activity is termed 'biological nitrification inhibition' (BNI). With recent developments in methodology for in-situ measurement of nitrification inhibition, it is now possible to characterize BNI function in plants. This review assesses the current status of our understanding of the production and release of biological nitrification inhibitors (BNIs) and their potential in improving NUE in agriculture. A suite of genetic, soil and environmental factors regulate BNI activity in plants. BNI-function can be genetically exploited to improve the BNI-capacity of major food- and feed-crops to develop next-generation production systems with reduced nitrification and N2O emission rates to benefit both agriculture and the environment. The feasibility of such an approach is discussed based on the progresses made.

  14. Suppression pheromone and cockroach rank formation

    NASA Astrophysics Data System (ADS)

    Kou, Rong; Chang, Huan-Wen; Chen, Shu-Chun; Ho, Hsiao-Yung

    2009-06-01

    Although agonistic behaviors in the male lobster cockroach ( Nauphoeta cinerea) are well known, the formation of an unstable hierarchy has long been a puzzle. In this study, we investigate how the unstable dominance hierarchy in N. cinerea is maintained via a pheromone signaling system. In agonistic interactions, aggressive posture (AP) is an important behavioral index of aggression. This study showed that, during the formation of a governing hierarchy, thousands of nanograms of 3-hydroxy-2-butanone (3H-2B) were released by the AP-adopting dominant in the first encounter fight, then during the early domination period and that this release of 3H-2B was related to rank maintenance, but not to rank establishment. For rank maintenance, 3H-2B functioned as a suppression pheromone, which suppressed the fighting capability of rivals and kept them in a submissive state. During the period of rank maintenance, as the dominant male gradually decreased his 3H-2B release, the fighting ability of the subordinate gradually developed, as shown by the increasing odds of a subordinate adopting an AP (OSAP). The OSAP was negatively correlated with the amount of 3H-2B released by the dominant and positively correlated with the number of domination days. The same OSAP could be achieved earlier by reducing the amount of 3H-2B released by the dominant indicates that whether the subordinate adopts an offensive strategy depends on what the dominant is doing.

  15. Suppression of Dopamine Neurons Mediates Reward

    PubMed Central

    Yamagata, Nobuhiro; Abe, Ayako; Tanimoto, Hiromu

    2016-01-01

    Massive activation of dopamine neurons is critical for natural reward and drug abuse. In contrast, the significance of their spontaneous activity remains elusive. In Drosophila melanogaster, depolarization of the protocerebral anterior medial (PAM) cluster dopamine neurons en masse signals reward to the mushroom body (MB) and drives appetitive memory. Focusing on the functional heterogeneity of PAM cluster neurons, we identified that a single class of PAM neurons, PAM-γ3, mediates sugar reward by suppressing their own activity. PAM-γ3 is selectively required for appetitive olfactory learning, while activation of these neurons in turn induces aversive memory. Ongoing activity of PAM-γ3 gets suppressed upon sugar ingestion. Strikingly, transient inactivation of basal PAM-γ3 activity can substitute for reward and induces appetitive memory. Furthermore, we identified the satiety-signaling neuropeptide Allatostatin A (AstA) as a key mediator that conveys inhibitory input onto PAM-γ3. Our results suggest the significance of basal dopamine release in reward signaling and reveal a circuit mechanism for negative regulation. PMID:27997541

  16. Wireless Inductive Power Device Suppresses Blade Vibrations

    NASA Technical Reports Server (NTRS)

    Morrison, Carlos R.; Provenza, Andrew J.; Choi, Benjamin B.; Bakhle, Milind A.; Min, James B.; Stefko, George L.; Duffy, Kirsten P.; Fougers, Alan J.

    2011-01-01

    Vibration in turbomachinery can cause blade failures and leads to the use of heavier, thicker blades that result in lower aerodynamic efficiency and increased noise. Metal and/or composite fatigue in the blades of jet engines has resulted in blade destruction and loss of lives. Techniques for suppressing low-frequency blade vibration, such as gtuned circuit resistive dissipation of vibratory energy, h or simply "passive damping," can require electronics incorporating coils of unwieldy dimensions and adding unwanted weight to the rotor. Other approaches, using vibration-dampening devices or damping material, could add undesirable weight to the blades or hub, making them less efficient. A wireless inductive power device (WIPD) was designed, fabricated, and developed for use in the NASA Glenn's "Dynamic Spin Rig" (DSR) facility. The DSR is used to simulate the functionality of turbomachinery. The relatively small and lightweight device [10 lb (approx.=4.5 kg)] replaces the existing venerable and bulky slip-ring. The goal is the eventual integration of this technology into actual turbomachinery such as jet engines or electric power generators, wherein the device will facilitate the suppression of potentially destructive vibrations in fan blades. This technology obviates slip rings, which require cooling and can prove unreliable or be problematic over time. The WIPD consists of two parts: a remote element, which is positioned on the rotor and provides up to 100 W of electrical power to thin, lightweight piezoelectric patches strategically placed on/in fan blades; and a stationary base unit that wirelessly communicates with the remote unit. The base unit supplies inductive power, and also acts as an input and output corridor for wireless measurement, and active control command to the remote unit. Efficient engine operation necessitates minimal disturbance to the gas flow across the turbine blades in any effort to moderate blade vibration. This innovation makes it

  17. Detection and Description of Soils with Specific Nematode Suppressiveness

    PubMed Central

    Westphal, Andreas

    2005-01-01

    Soils with specific suppressiveness to plant-parasitic nematodes are of interest to define the mechanisms that regulate population density. Suppressive soils prevent nematodes from establishing and from causing disease, and they diminish disease severity after initial nematode damage in continuous culturing of a host. A range of non-specific and specific soil treatments, followed by infestation with a target nematode, have been employed to identify nematode-suppressive soils. Biocidal treatments, soil transfer tests, and baiting approaches together with observations of the plant-parasitic nematode in the root zone of susceptible host plants have improved the understanding of nematode-suppressive soils. Techniques to demonstrate specific soil suppressiveness against plant-parasitic nematodes are compared in this review. The overlap of studies on soil suppressiveness with recent advances in soil health and quality is briefly discussed. The emphasis is on methods (or criteria) used to detect and identify soils that maintain specific soil suppressiveness to plant-parasitic nematodes. While biocidal treatments can detect general and specific soil suppressiveness, soil transfer studies, by definition, apply only to specific soil suppressiveness. Finally, potential strategies to exploit suppressive soils are presented. PMID:19262851

  18. Exploiting Symmetry for Quantum Error Suppression

    NASA Astrophysics Data System (ADS)

    Nam, Yunseong; Blümel, Reinhold

    2016-05-01

    In light of recent experimental progress in quantum computing, the time is ripe to discuss quantum computer hardware optimization. Taking the digital/analog hybrid nature of quantum computers into account, choosing a proper processor architecture for a given quantum algorithm becomes crucial in making quantum computing a practical reality. As a first step in this direction, we investigate the robustness of quantum adders with respect to naturally occurring hardware defects and errors. In particular, we compare the robustness of the ripple-carry adder to that of the quantum Fourier adder. We show that, surprisingly, when used in Shor's algorithm, the quantum Fourier adder may well be more robust than the ripple-carry adder. We present a noise suppression scheme, called symmetric noise, applicable to the quantum Fourier architecture, that, measured in terms of fidelity, results in an order-of-magnitude performance boost.

  19. Circuit protection devices for transient suppression

    NASA Technical Reports Server (NTRS)

    Childers, Richard

    1991-01-01

    The Electromer Corporation has developed a series of transient voltage suppression components based on a patented, specially formulated PolyClamp (trademark) material. PolyClamp components are a new class of transient voltage surge suppressors that extend the range of protection offered by transients protectors. The PolyClamp transient surge suppressors provide low capacitance, high energy capability, and packaging flexibility. A wide variety of applications can be protected. A tube and ferrule configuration was designed to be used with MIL/Aerospace style connectors and is designed to meet the applicable environmental, mechanical, and electrical requirements as defined by the United States and European defence standards performance requirements. Here, PolyClamp is compared with current transient surge suppressors. Typical performance and design are discussed.

  20. Axionic suppression of plasma wakefield acceleration

    NASA Astrophysics Data System (ADS)

    Burton, D. A.; Noble, A.; Walton, T. J.

    2016-09-01

    Contemporary attempts to explain the existence of ultra-high energy cosmic rays using plasma-based wakefield acceleration deliberately avoid non-standard model particle physics. However, such proposals exploit some of the most extreme environments in the Universe and it is conceivable that hypothetical particles outside the standard model have significant implications for the effectiveness of the acceleration process. Axions solve the strong CP problem and provide one of the most important candidates for cold dark matter, and their potential significance in the present context should not be overlooked. Our analysis of the field equations describing a plasma augmented with axions uncovers a dramatic axion-induced suppression of the energy gained by a test particle in the wakefield driven by a particle bunch, or an intense pulse of electromagnetic radiation, propagating at ultra-relativistic speeds within the strongest magnetic fields in the Universe.

  1. Inhibiting macrophage proliferation suppresses atherosclerotic plaque inflammation.

    PubMed

    Tang, Jun; Lobatto, Mark E; Hassing, Laurien; van der Staay, Susanne; van Rijs, Sarian M; Calcagno, Claudia; Braza, Mounia S; Baxter, Samantha; Fay, Francois; Sanchez-Gaytan, Brenda L; Duivenvoorden, Raphaël; Sager, Hendrik; Astudillo, Yaritzy M; Leong, Wei; Ramachandran, Sarayu; Storm, Gert; Pérez-Medina, Carlos; Reiner, Thomas; Cormode, David P; Strijkers, Gustav J; Stroes, Erik S G; Swirski, Filip K; Nahrendorf, Matthias; Fisher, Edward A; Fayad, Zahi A; Mulder, Willem J M

    2015-04-01

    Inflammation drives atherosclerotic plaque progression and rupture, and is a compelling therapeutic target. Consequently, attenuating inflammation by reducing local macrophage accumulation is an appealing approach. This can potentially be accomplished by either blocking blood monocyte recruitment to the plaque or increasing macrophage apoptosis and emigration. Because macrophage proliferation was recently shown to dominate macrophage accumulation in advanced plaques, locally inhibiting macrophage proliferation may reduce plaque inflammation and produce long-term therapeutic benefits. To test this hypothesis, we used nanoparticle-based delivery of simvastatin to inhibit plaque macrophage proliferation in apolipoprotein E deficient mice (Apoe(-/-) ) with advanced atherosclerotic plaques. This resulted in rapid reduction of plaque inflammation and favorable phenotype remodeling. We then combined this short-term nanoparticle intervention with an eight-week oral statin treatment, and this regimen rapidly reduced and continuously suppressed plaque inflammation. Our results demonstrate that pharmacologically inhibiting local macrophage proliferation can effectively treat inflammation in atherosclerosis.

  2. Inhibiting macrophage proliferation suppresses atherosclerotic plaque inflammation

    PubMed Central

    Tang, Jun; Lobatto, Mark E.; Hassing, Laurien; van der Staay, Susanne; van Rijs, Sarian M.; Calcagno, Claudia; Braza, Mounia S.; Baxter, Samantha; Fay, Francois; Sanchez-Gaytan, Brenda L.; Duivenvoorden, Raphaël; Sager, Hendrik B.; Astudillo, Yaritzy M.; Leong, Wei; Ramachandran, Sarayu; Storm, Gert; Pérez-Medina, Carlos; Reiner, Thomas; Cormode, David P.; Strijkers, Gustav J.; Stroes, Erik S. G.; Swirski, Filip K.; Nahrendorf, Matthias; Fisher, Edward A.; Fayad, Zahi A.; Mulder, Willem J. M.

    2015-01-01

    Inflammation drives atherosclerotic plaque progression and rupture, and is a compelling therapeutic target. Consequently, attenuating inflammation by reducing local macrophage accumulation is an appealing approach. This can potentially be accomplished by either blocking blood monocyte recruitment to the plaque or increasing macrophage apoptosis and emigration. Because macrophage proliferation was recently shown to dominate macrophage accumulation in advanced plaques, locally inhibiting macrophage proliferation may reduce plaque inflammation and produce long-term therapeutic benefits. To test this hypothesis, we used nanoparticle-based delivery of simvastatin to inhibit plaque macrophage proliferation in apolipoprotein E–deficient mice (Apoe−/−) with advanced atherosclerotic plaques. This resulted in the rapid reduction of plaque inflammation and favorable phenotype remodeling. We then combined this short-term nanoparticle intervention with an 8-week oral statin treatment, and this regimen rapidly reduced and continuously suppressed plaque inflammation. Our results demonstrate that pharmacologically inhibiting local macrophage proliferation can effectively treat inflammation in atherosclerosis. PMID:26295063

  3. Eigenspace techniques for active flutter suppression

    NASA Technical Reports Server (NTRS)

    Garrard, William L.; Liebst, Bradley S.; Farm, Jerome A.

    1987-01-01

    The use of eigenspace techniques for the design of an active flutter suppression system for a hypothetical research drone is discussed. One leading edge and two trailing edge aerodynamic control surfaces and four sensors (accelerometers) are available for each wing. Full state control laws are designed by selecting feedback gains which place closed loop eigenvalues and shape closed loop eigenvectors so as to stabilize wing flutter and reduce gust loads at the wing root while yielding accepatable robustness and satisfying constrains on rms control surface activity. These controllers are realized by state estimators designed using an eigenvalue placement/eigenvector shaping technique which results in recovery of the full state loop transfer characteristics. The resulting feedback compensators are shown to perform almost as well as the full state designs. They also exhibit acceptable performance in situations in which the failure of an actuator is simulated.

  4. Pulse compression and prepulse suppression apparatus

    DOEpatents

    Dane, Clifford B.; Hackel, Lloyd A.; George, Edward V.; Miller, John L.; Krupke, William F.

    1993-01-01

    A pulse compression and prepulse suppression apparatus (10) for time compressing the output of a laser (14). A pump pulse (46) is separated from a seed pulse (48) by a first polarized beam splitter (20) according to the orientation of a half wave plate (18). The seed pulse (48) is directed into an SBS oscillator (44) by two plane mirrors (22, 26) and a corner mirror (24), the corner mirror (24) being movable to adjust timing. The pump pulse (46) is directed into an SBS amplifier 34 wherein SBS occurs. The seed pulse (48), having been propagated from the SBS oscillator (44), is then directed through the SBS amplifier (34) wherein it sweeps the energy of the pump pulse (46) out of the SBS amplifier (34) and is simultaneously compressed, and the time compressed pump pulse (46) is emitted as a pulse output (52). A second polarized beam splitter (38) directs any undepleted pump pulse 58 away from the SBS oscillator (44).

  5. Pulse compression and prepulse suppression apparatus

    DOEpatents

    Dane, C.B.; Hackel, L.A.; George, E.V.; Miller, J.L.; Krupke, W.F.

    1993-11-09

    A pulse compression and prepulse suppression apparatus (10) for time compressing the output of a laser (14). A pump pulse (46) is separated from a seed pulse (48) by a first polarized beam splitter (20) according to the orientation of a half wave plate (18). The seed pulse (48) is directed into an SBS oscillator (44) by two plane mirrors (22, 26) and a corner mirror (24), the corner mirror (24) being movable to adjust timing. The pump pulse (46) is directed into an SBS amplifier 34 wherein SBS occurs. The seed pulse (48), having been propagated from the SBS oscillator (44), is then directed through the SBS amplifier (34) wherein it sweeps the energy of the pump pulse (46) out of the SBS amplifier (34) and is simultaneously compressed, and the time compressed pump pulse (46) is emitted as a pulse output (52). A second polarized beam splitter (38) directs any undepleted pump pulse 58 away from the SBS oscillator (44).

  6. Vibration suppression in a large space structure

    NASA Technical Reports Server (NTRS)

    Narendra, Kumpati S.

    1988-01-01

    The Yale University Center for Systems Science and the NASA Johnson Space Center collaborated in a study of vibration suppression in a large space structure during the period January 1985 to August 1987. The research proposal submitted by the Center to NASA concerned disturbance isolation in flexible space structures. The general objective of the proposal was to create within the Center a critical mass of expertise on problems related to the dynamics and control of large flexible space structures. A specific objective was to formulate both passive and active control strategies for the disturbance isolation problem. Both objectives were achieved during the period of the contract. While an extensive literature exists on the control of flexible space structures, it is generally acknowledged that many important questions remain open at even a fundamental level. Hence, instead of studying grossly simplified models of complex structural systems, it was decided as a first step to confine attention to detailed and thorough analyses of simple structures.

  7. Desferrioxamine suppresses Plasmodium falciparum in Aotus monkeys.

    PubMed

    Pollack, S; Rossan, R N; Davidson, D E; Escajadillo, A

    1987-02-01

    Clinical observation has suggested that iron deficiency may be protective in malaria, and we have found that desferrioxamine (DF), an iron-specific chelating agent, inhibited Plasmodium falciparum growth in vitro. It was difficult to be confident that DF would be effective in an intact animal, however, because continuous exposure to DF was required in vitro and, in vivo, DF is rapidly excreted. Also, the in vitro effect of DF was overcome by addition of iron to the culture and in vivo there are potentially high local iron concentrations when iron is absorbed from the diet or released from reticuloendothelial cells. We now show that DF given by constant subcutaneous infusion does suppress parasitemia in P. falciparum-infected Aotus monkeys.

  8. Reverse wave suppression in unstable ring resonator

    NASA Astrophysics Data System (ADS)

    Mirels, H.; Chodzko, R. A.; Bernard, J. M.; Giedt, R. R.; Coffer, J. G.

    1984-12-01

    Criteria for effective reverse-wave suppression (RWS) in CW and pulsed unstable ring lasers with inhomogeneously broadened media are determined theoretically, and the performance of a CW HF linear ring resonator (Chodzko et al., 1976) and of two configurations of a pulsed CO2 annular beam-rotation/internal-axicon (BRIA) resonator (Bullock et al., 1979) without and with an RWS mirror is evaluated experimentally. In the CW laser, the average forward-wave (FW) and RW power values are shown to be 61 and 39 W without RWS and 110 and 2.7 W with RWS, corresponding to a FW/RW power ratio of 41; in the pulsed BRIA lasers, power ratios of about 20 are achieved, but the RWS effectiveness is found to be highly sensitive to RWS-mirror and cavity misalignment. Graphs, drawings, tables, and photographs of typical waveforms are included.

  9. Passive runaway electron suppression in tokamak disruptions

    SciTech Connect

    Smith, H. M.; Helander, P.

    2013-07-15

    Runaway electrons created in disruptions pose a serious problem for tokamaks with large current. It would be desirable to have a runaway electron suppression method which is passive, i.e., a method that does not rely on an uncertain disruption prediction system. One option is to let the large electric field inherent in the disruption drive helical currents in the wall. This would create ergodic regions in the plasma and increase the runaway losses. Whether these regions appear at a suitable time and place to affect the formation of the runaway beam depends on disruption parameters, such as electron temperature and density. We find that it is difficult to ergodize the central plasma before a beam of runaway current has formed. However, the ergodic outer region will make the Ohmic current profile contract, which can lead to instabilities that yield large runaway electron losses.

  10. Upsilon suppression in the QGP at the LHC

    NASA Astrophysics Data System (ADS)

    Wolschin, Georg

    2016-12-01

    The suppression of ϒ-mesons in the hot quark-gluon medium in PbPb collisions is accounted for in a model that encompasses gluodissociation, collisional damping, screening, and reduced feed-down. Theoretical results for centrality-dependent suppression factors of the ϒ (1 S) and ϒ (2 S) states are compared with CMS data. The measured ground state suppression is well represented, but discrepancies between data and model persist for peripheral ϒ (2 S)-events that require additional suppression mechanisms. The pT-dependence of the suppression is discussed and a prediction for the centrality-dependent ϒ (1 S) suppression in 5.02 TeV PbPb is made.

  11. An appetite suppressant from Hoodia species.

    PubMed

    van Heerden, Fanie R; Marthinus Horak, R; Maharaj, Vinesh J; Vleggaar, Robert; Senabe, Jeremiah V; Gunning, Philip J

    2007-10-01

    Studies conducted at the Council for Scientific and Industrial Research (CSIR, South Africa) identified extracts from Hoodia species, in particular Hoodia pilifera and Hoodia gordonii, as possessing appetite suppressing properties. Two pregnane glycosides were isolated by fractionation of the dried stems of H. gordonii. Their structures were determined as 3beta-[beta-D-thevetopyranosyl-(1-->4)-beta-D- cymaropyranosyl-(1-->4)-beta-D-cymaropyranosyloxy]-12beta-tigloyloxy-14beta-hydroxypregn-5-en-20-one (1) and 3beta-[beta-D-cymaropyranosyl-(1-->4)-beta-D-6-thevetopyranosyl-(1-->4)-beta-D-cymaropyranosyl-(1-->4)-beta-D-cymaropyranosyloxy]-12beta-tigloyloxy-14beta-hydroxypregn-5-en-20-one (2) on the basis of spectroscopic studies and conversion to known compounds. Compounds 1 and 2 were also isolated from H. pilifera. Compound 1 was tested for its appetite suppressant properties in rats by oral gavage at 6.25-50 mg/kg and the results showed that all doses resulted in a decrease of food consumption over an eight day period and a body mass decrease when compared to the control sample receiving only the vehicle. In a comparative study against a fenfluramine control sample, compound 1 resulted in a reduction in food intake over the study period, with a concomitant overall decrease in body weight while fenfluramine resulted in a small decrease in food intake, but an increase in body weight (though less than control group) over the same period of time.

  12. Suppressive effects of ketamine on macrophage functions

    SciTech Connect

    Chang Yi; Chen, T.-L.; Sheu, J.-R.; Chen, R.-M. . E-mail: rmchen@tmu.edu.tw

    2005-04-01

    Ketamine is an intravenous anesthetic agent. Clinically, induction of anesthesia with ketamine can cause immunosuppression. Macrophages play important roles in host defense. In this study, we attempted to evaluate the effects of ketamine on macrophage functions and its possible mechanism using mouse macrophage-like Raw 264.7 cells as the experimental model. Exposure of macrophages to 10 and 100 {mu}M ketamine, which correspond to 0.1 and 1 times the clinically relevant concentration, for 1, 6, and 24 h had no effect on cell viability or lactate dehydrogenase release. When the administered concentration reached 1000 {mu}M, ketamine caused a release of lactate dehydrogenase and cell death. Ketamine, at 10 and 100 {mu}M, did not affect the chemotactic activity of macrophages. Administration of 1000 {mu}M ketamine in macrophages resulted in a decrease in cell migration. Treatment of macrophages with ketamine reduced phagocytic activities. The oxidative ability of macrophages was suppressed by ketamine. Treatment with lipopolysaccharide induced TNF-{alpha}, IL-1{beta}, and IL-6 mRNA in macrophages. Administration of ketamine alone did not influence TNF-{alpha}, IL-1{beta}, or IL-6 mRNA production. Meanwhile, cotreatment with ketamine and lipopolysaccharide significantly inhibited lipopolysaccharide-induced TNF-{alpha}, IL-1{beta}, and IL-6 mRNA levels. Exposure to ketamine led to a decrease in the mitochondrial membrane potential. However, the activity of mitochondrial complex I NADH dehydrogenase was not affected by ketamine. This study shows that a clinically relevant concentration of ketamine (100 {mu}M) can suppress macrophage function of phagocytosis, its oxidative ability, and inflammatory cytokine production possibly via reduction of the mitochondrial membrane potential instead of direct cellular toxicity.

  13. SUPPRESSION OF STAR FORMATION IN NGC 1266

    SciTech Connect

    Alatalo, Katherine; Lanz, Lauranne; Bitsakis, Theodoros; Appleton, Philip N.; Ogle, Patrick M.; Lacy, Mark; Lonsdale, Carol J.; Nyland, Kristina; Meier, David S.; Cales, Sabrina L.; Chang, Philip; Davis, Timothy A.; De Zeeuw, P. T.; Martín, Sergio

    2015-01-01

    NGC 1266 is a nearby lenticular galaxy that harbors a massive outflow of molecular gas powered by the mechanical energy of an active galactic nucleus (AGN). It has been speculated that such outflows hinder star formation (SF) in their host galaxies, providing a form of feedback to the process of galaxy formation. Previous studies, however, indicated that only jets from extremely rare, high-power quasars or radio galaxies could impart significant feedback on their hosts. Here we present detailed observations of the gas and dust continuum of NGC 1266 at millimeter wavelengths. Our observations show that molecular gas is being driven out of the nuclear region at M-dot {sub out}≈110 M{sub ⊙} yr{sup –1}, of which the vast majority cannot escape the nucleus. Only 2 M {sub ☉} yr{sup –1} is actually capable of escaping the galaxy. Most of the molecular gas that remains is very inefficient at forming stars. The far-infrared emission is dominated by an ultra-compact (≲ 50 pc) source that could either be powered by an AGN or by an ultra-compact starburst. The ratio of the SF surface density (Σ{sub SFR}) to the gas surface density (Σ{sub H{sub 2}}) indicates that SF is suppressed by a factor of ≈50 compared to normal star-forming galaxies if all gas is forming stars, and ≈150 for the outskirt (98%) dense molecular gas if the central region is powered by an ultra-compact starburst. The AGN-driven bulk outflow could account for this extreme suppression by hindering the fragmentation and gravitational collapse necessary to form stars through a process of turbulent injection. This result suggests that even relatively common, low-power AGNs are able to alter the evolution of their host galaxies as their black holes grow onto the M-σ relation.

  14. Suppression of human spermatogenesis by testosterone implants.

    PubMed

    Handelsman, D J; Conway, A J; Boylan, L M

    1992-11-01

    Hormonally induced azoospermia is an effective, reversible form of male contraception; however, some men treated with weekly im testosterone enanthate (TE) injections fail to become azoospermic. As weekly injections cause widely fluctuating and supraphysiological testosterone levels, we tested the hypothesis that more stable, physiological testosterone levels would consistently produce azoospermia. Using a depot testosterone formulation which provides stable, physiological range testosterone levels for up to 6 months, we studied nine men before and after insertion of six 200 mg testosterone implants under the abdominal wall skin and compared the results with 38 men treated in a previous study with weekly im injections of 200 mg TE. Testosterone implants suppressed sperm output to near-azoospermia between the second to fourth postimplant months returning to normal by the sixth postimplant month. The fall in sperm output at the first month was greater after testosterone implants than TE injections (58% vs. 17%, P = 0.011) but similar proportions of men became azoospermic (5/9 vs. 25/38) or severely oligozoospermic (< 1 million/ml; 9/9 vs. 37/38). Plasma testosterone and estradiol levels remained mostly within the eugonadal range after implants but were markedly supraphysiological during TE injections. Both treatments suppressed immunoreactive LH and FSH to undetectable levels by ultrasensitive fluoroimmunoassay. Sex hormone-binding globulin levels were decreased and PRL levels increased by TE injections but neither was changed by testosterone implants. Prostate-specific antigen demonstrated a small rise of marginal significance (P = 0.065) after testosterone implants. Fewer men experienced acne after implants (0/9 vs. 25/38, p = 0.0004). Therefore a depot testosterone preparation with quasi-zero-order release demonstrates higher dose efficiency with similar (but not uniform) efficacy at inducing azoospermia but may cause fewer androgenic side-effects than weekly TE

  15. Range sidelobe suppression in wideband phased array radars

    NASA Astrophysics Data System (ADS)

    Belcher, Melvin L., Jr.; Moss, Karen M.

    The authors delineate some considerations in achieving RSL (range sidelobe) suppression in wideband phased arrays. Attention is given to wideband radar characteristics suppression of spurious signals, and sources of wideband RSLs. It is suggested that the parallelism associated with the transmitter and antenna paths should mitigate associated uncorrelated time-varying error modulation. The exciter can be a major RSL contributor unless spurious signal suppression with the SSBM (single sideband modulator) is emphasized in design and calibration procedures.

  16. Proof Testing of a Candidate Category 3 Suppressive Shield

    DTIC Science & Technology

    1976-08-01

    Susquehanna Instruments ST-2 piezoelectric transducers were used to measure blast pressure external to the shield at ground level. The ST-2...Calibration of Side-on Blast Pressure Measurements 12 Category 3 Suppressive Shield Explosive Containment Tests, Instrumental Details 13 Category...3 Suppressive Shield Test Bl-1 Side-on Blast Pressure Measurements 27 Categroy 3 Suppressive Shield Tests B2-1 and B2-2 Side-on Blast Pressure

  17. Suppression of Density Fluctuations in a Quantum Degenerate Fermi Gas

    SciTech Connect

    Sanner, Christian; Su, Edward J.; Keshet, Aviv; Gommers, Ralf; Shin, Yong-il; Huang Wujie; Ketterle, Wolfgang

    2010-07-23

    We study density profiles of an ideal Fermi gas and observe Pauli suppression of density fluctuations (atom shot noise) for cold clouds deep in the quantum degenerate regime. Strong suppression is observed for probe volumes containing more than 10 000 atoms. Measuring the level of suppression provides sensitive thermometry at low temperatures. After this method of sensitive noise measurements has been validated with an ideal Fermi gas, it can now be applied to characterize phase transitions in strongly correlated many-body systems.

  18. Tactical Checkpoint: Hail/Warn Suppress/Stop (Briefing Charts)

    DTIC Science & Technology

    2010-11-15

    U.S. Army Research, Development and Engineering Command Tactical Checkpoint: Hail/Warn Suppress /Stop Target Behavioral Response Laboratory... SUPPRESS /STOP Presented at the 2010 Directed Energies Professional Society Meeting, 15-19 November 2010. 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c...driver that is approaching a checkpoint. The laser, MCNC light, and the windshield obscuration were evaluated for their suppression capabilities (ability

  19. Methods for suppressing isomerization of olefin metathesis products

    DOEpatents

    Firth, Bruce E.; Kirk, Sharon E.; Gavaskar, Vasudeo S.

    2015-09-22

    A method for suppressing isomerization of an olefin metathesis product produced in a metathesis reaction includes adding an isomerization suppression agent to a mixture that includes the olefin metathesis product and residual metathesis catalyst from the metathesis reaction under conditions that are sufficient to passivate at least a portion of the residual metathesis catalyst. The isomerization suppression agent is phosphorous acid, a phosphorous acid ester, phosphinic acid, a phosphinic acid ester or combinations thereof. Methods of refining natural oils are described.

  20. Optimal Tuning for Disturbance Suppression Mechanism for Model Predictive Control

    NASA Astrophysics Data System (ADS)

    Tange, Yoshio; Nakazawa, Chikashi

    Disturbance suppression is one of most required performances in process control. We recently proposed a new disturbance suppression mechanism applicable for model predictive control in order to enhance disturbance suppression performance for ramp-like disturbances. The proposed method utilized the prediction error of controlled values and generates a disturbance compensation signal by a constant gain feedback. In this paper, we propose an improved version of the disturbance suppression mechanism by applying a low-pass filter and parameter tuning methods by which we can make the mechanism more tolerant to various disturbances such as ramp, step, and other supposable ones. We also show numerical simulation results with an oil distillation tower plant.

  1. A comparative study of terrestrial gamma dose rate in air measured by thermoluminescent dosimeter, portable survey meter and HPGe gamma spectrometer.

    PubMed

    Huang, Yan-Jun; Guo, Gui-Yin; He, Yi; Yang, Li-Tao; Shan, Zhen; Chen, Chao-Feng; Shang-Guan, Zhi-Hong

    2016-11-01

    In this paper, three different widely-used measurement techniques for environmental gamma dose rate were studied and compared, i.e., the thermoluminescent dosimeter, the portable survey meter and the spectrometric analysis. Thirteen investigation sites were selected, and the TLDs were arranged to accumulate the radiation signals during an interval of about one quarter, the instant dose rates by using a portable survey meter were collected around the site, and top surface soils were sampled in the surroundings for radionuclides analyzing in laboratory. The results from these methods were compared, which revealed high correlations. The differences and possible uncertainties for the three methods were analyzed, inspired a further study should be conducted to have more successful estimation of dose rate in surface air.

  2. Improvement of the MCNP simulated n-gamma spectrometer response function using the new ENDF/B-VI evaluations for thermal neutron capture

    NASA Astrophysics Data System (ADS)

    Cywicka-Jakiel, T.; Zorski, T.

    2007-09-01

    An impact of the improved nuclear data library for thermal neutron capture (ENDF/B-VI.8) on the numerically simulated response of the spectrometric n-gamma well logging (sNGL) probe, SO-5-90-SN type, has been investigated. For this aim the MCNP simulations have been done using two kinds of data libraries for radiative capture: the commonly used ENDF/B-VI.2 (ENDF60) and the new ENDF/B-VI. 8 (ACTIA). MCNP simulations concerned the n-gamma benchmark experiment which was performed at the Polish calibration station in Zielona Góra to investigate the influence of chlorine in borehole on the tool readings and thus on the accuracy of quantitative elemental analysis for the main rock elements: Si, Ca and Fe. High quality of the nuclear data for radiative capture in Cl and Al have been of special interest as the ENDF60 library contains an imperfect data for Cl and there is no delay gamma-ray line of energy 1.7791 MeV from thermal neutron capture in Al. The last element is the main construction material for the SO-5-90-SN spectrometer. The advantage of the new ACTIA library over the ENDF60 was shown through the better matching of the experimental and simulated gamma-ray spectra from thermal neutron capture. As a consequence the Si, Ca and Fe rock contents obtained from the MCNP modeling with the use of ACTIA data, fit well their reference values regarded as "true". The accuracies for the Si, Ca and Fe determination have been improved by about 63%, 35% and 51%, respectively.

  3. Development of a low-noise, 4th-order readout ASIC for CdZnTe detectors in gamma spectrometer applications

    NASA Astrophysics Data System (ADS)

    Wang, Jia; Su, Lin; Wei, Xiaomin; Zheng, Ran; Hu, Yann

    2016-09-01

    This paper presents an ASIC readout circuit development, which aims to achieve low noise. In order to compensate the leakage current and improve gain, a dual-stage CSA has been utilized. A 4th-order high-linearity shaper is proposed to obtain a Semi-Gaussian wave and further decrease the noise induced by the leakage current. The ASIC has been designed and fabricated in a standard commercial 2P4M 0.35 μm CMOS process. Die area of one channel is about 1190 μm×147 μm. The input charge range is 1.8 fC. The peaking time can be adjusted from 1 μs to 3 μs. Measured ENC is about 55e- (rms) at input capacitor of 0 F. The gain is 271 mV/fC at the peaking time of 1 μs.

  4. To suppress, or not to suppress? That is repression: controlling intrusive thoughts in addictive behaviour.

    PubMed

    Moss, Antony C; Erskine, James A K; Albery, Ian P; Allen, James Richard; Georgiou, George J

    2015-05-01

    Research to understand how individuals cope with intrusive negative or threatening thoughts suggests a variety of different cognitive strategies aimed at thought control. In this review, two of these strategies--thought suppression and repressive coping--are discussed in the context of addictive behaviour. Thought suppression involves conscious, volitional attempts to expel a thought from awareness, whereas repressive coping, which involves the avoidance of thoughts without the corresponding conscious intention, appears to be a far more automated process. Whilst there has been an emerging body of research exploring the role of thought suppression in addictive behaviour, there remains a dearth of research which has considered the role of repressive coping in the development of, and recovery from, addiction. Based on a review of the literature, and a discussion of the supposed mechanisms which underpin these strategies for exercising mental control, a conceptual model is proposed which posits a potential common mechanism. This model makes a number of predictions which require exploration in future research to fully understand the cognitive strategies utilised by individuals to control intrusive thoughts related to their addictive behaviour.

  5. Chronic Juvenile Delinquency and the "Suppression Effect": An Exploratory Study.

    ERIC Educational Resources Information Center

    Fraser, Mark; Norman, Michael

    1988-01-01

    Notes that fear of apprehension and punishment have been reported to suppress juvenile crime. Discusses suppression effect in regard to the correlates of chronic juvenile delinquency and exploratory evidence that youth who commit large volume of crime do not fear sanctions imposed by juvenile court any more than youth who commit only one offense…

  6. Social hierarchy and depression: the role of emotion suppression.

    PubMed

    Langner, Carrie A; Epel, Elissa S; Matthews, Karen A; Moskowitz, Judith T; Adler, Nancy E

    2012-01-01

    Position in the social hierarchy is a major determinant of health outcomes. We examined the associations between aspects of social hierarchy and depressive symptoms with a specific focus on one potential psychological mechanism: emotion suppression. Suppressing negative emotion has mental health costs, but individuals with low social power and low social status may use these strategies to avoid conflict. Study 1 assessed perceived social power, tendency to suppress negative emotion, and depressive symptoms in a community sample of women. Low social power was related to greater depressive symptoms, and this relationship was partially mediated by emotion suppression. Study 2 examined education as a proxy for social hierarchy position, anger suppression, and depressive symptoms in a national, longitudinal cohort study (The coronary artery risk development in young adults [CARDIA] study; Cutter et al., 1991). Much as in study 1, low education levels were correlated with greater depressive symptoms, and this relationship was partially mediated by anger suppression. Further, suppression mediated the relationship between low education and subsequent depression up to 15 years later. These findings support the theory that social hierarchy affects mental health in part through a process of emotion suppression.

  7. 48 CFR 452.236-78 - Fire Suppression and Liability.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 4 2014-10-01 2014-10-01 false Fire Suppression and... Fire Suppression and Liability. As prescribed in § 436.578, the following clause may be inserted in contracts awarded for Integrated Resource Service Contracts (IRSC) awarded for the Forest Service....

  8. Preliminary Evidence for Reduced Auditory Lateral Suppression in Schizophrenia

    PubMed Central

    Ramage, Erin. M.; Weintraub, David M.; Vogel, Sally J.; Sutton, Griffin P.; Ringdahl, Erik N.; Allen, Daniel N.; Snyder, Joel S.

    2014-01-01

    Background Well-documented auditory processing deficits such as impaired frequency discrimination and reduced suppression of auditory brain responses in schizophrenia (SZ) may contribute to abnormal auditory functioning in everyday life. Lateral suppression of non-stimulated neurons by stimulated neurons has not been extensively assessed in SZ and likely plays an important role in precise encoding of sounds. Therefore, this study evaluated whether lateral suppression of activity in auditory cortex is impaired in SZ. Methods SZ participants and control participants watched a silent movie with subtitles while listening to trials composed of a 0.5 s control stimulus (CS), a 3 s filtered masking noise (FN), and a 0.5 s test stimulus (TS). The CS and TS were identical on each trial and had energy corresponding to the high energy (recurrent suppression) or low energy (lateral suppression) portions of the FN. Event-related potentials were recorded and suppression was measured as the amplitude change between CS and TS. Results Peak amplitudes of the auditory P2 component (160–260 ms) showed reduced lateral but not recurrent suppression in SZ participants. Conclusions Reduced lateral suppression in SZ participants may lead to overlap of neuronal populations representing different auditory stimuli. Such imprecise neural representations may contribute to the difficulties SZ participants have in discriminating complex stimuli in everyday life. PMID:25583249

  9. Thought Suppression and Meaning in Life: A Longitudinal Investigation

    ERIC Educational Resources Information Center

    Krause, Neal

    2007-01-01

    The purpose of this study is to see if older adults who experience problems with thought suppression tend to encounter greater difficulty deriving a sense of meaning in life. Data from a longitudinal nationwide survey of older people (N = 988) indicate that greater difficulty with thought suppression is associated with a decline in meaning over…

  10. Eye Contact Facilitates Awareness of Faces during Interocular Suppression

    ERIC Educational Resources Information Center

    Stein, Timo; Senju, Atsushi; Peelen, Marius V.; Sterzer, Philipp

    2011-01-01

    Eye contact captures attention and receives prioritized visual processing. Here we asked whether eye contact might be processed outside conscious awareness. Faces with direct and averted gaze were rendered invisible using interocular suppression. In two experiments we found that faces with direct gaze overcame such suppression more rapidly than…

  11. POTENTIAL ENVIRONMENTAL IMPACTS OF DUST SUPPRESSANTS: "ADVOIDING ANOTHER TIMES BEACH"

    EPA Science Inventory

    In the past decade, there has been an increased use of chemical dust suppressants such as i water, salts, asphalt emulsion, vegetable oils, molasses, synthetic polymers, mulches, and lignin 1 products. Dust suppressants abate dust by changing the physical properties of the soil s...

  12. 30 CFR 75.1107 - Fire suppression devices.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... approved by the Secretary shall be used in the hydraulic systems of such equipment. Such fluids shall be used in the hydraulic systems of other underground equipment unless fire suppression devices meeting... Fire-Resistant Hydraulic Fluids on Underground Equipment § 75.1107 Fire suppression devices. On...

  13. 30 CFR 75.1107 - Fire suppression devices.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... approved by the Secretary shall be used in the hydraulic systems of such equipment. Such fluids shall be used in the hydraulic systems of other underground equipment unless fire suppression devices meeting... Fire-Resistant Hydraulic Fluids on Underground Equipment § 75.1107 Fire suppression devices. On...

  14. 14 CFR 460.13 - Smoke detection and fire suppression.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Smoke detection and fire suppression. 460.13 Section 460.13 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION... Crew § 460.13 Smoke detection and fire suppression. An operator or crew must have the ability to...

  15. 14 CFR 460.13 - Smoke detection and fire suppression.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Smoke detection and fire suppression. 460.13 Section 460.13 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION... Crew § 460.13 Smoke detection and fire suppression. An operator or crew must have the ability to...

  16. Suppression of ultrafast supercontinuum generation in a salivary protein.

    PubMed

    Santhosh, Chidangil; Dharmadhikari, Aditya K; Alti, Kamlesh; Dharmadhikari, Jayashree A; Mathur, Deepak

    2007-01-01

    The first studies of the propagation of ultrafast (<45 fs) pulses of intense infrared light through protein media reveal that supercontinuum (white light) generation is severely suppressed in the presence of the protein alpha-amylase, a potential stress marker in human saliva. The continuum suppression capacity is attributed to the electron scavenging property of the protein.

  17. Social Hierarchy and Depression: The Role of Emotion Suppression

    PubMed Central

    Langner, Carrie A.; Epel, Elissa; Matthews, Karen; Moskowitz, Judith T.; Adler, Nancy

    2017-01-01

    Position in the social hierarchy is a major determinant of health outcomes. We examined the associations between aspects of social hierarchy and depressive symptoms with a specific focus on one potential psychological mechanism: emotion suppression. Suppressing negative emotion has mental health costs, but individuals with low social power and low social status may use these strategies to avoid conflict. Study 1 assessed perceived social power, tendency to suppress negative emotion, and depressive symptoms in a community sample of women. Low social power was related to greater depressive symptoms, and this relationship was partially mediated by emotion suppression. Study 2 examined education as a proxy for social hierarchy position, anger suppression, and depressive symptoms in a national, longitudinal cohort study (The Coronary Artery Risk Development in Young Adults (CARDIA) study). Similar to Study 1, low education levels were correlated with greater depressive symptoms, and this relationship was partially mediated by anger suppression. Further, suppression mediated the relationship between low education and subsequent depression up to 15 years later. These findings support the theory that social hierarchy affects mental health in part through a process of emotion suppression. PMID:22808688

  18. Suppressive mechanisms in visual motion processing: from perception to intelligence

    PubMed Central

    Tadin, Duje

    2015-01-01

    Perception operates on an immense amount of incoming information that greatly exceeds the brain's processing capacity. Because of this fundamental limitation, the ability to suppress irrelevant information is a key determinant of perceptual efficiency. Here, I will review a series of studies investigating suppressive mechanisms in visual motion processing, namely perceptual suppression of large, background-like motions. These spatial suppression mechanisms are adaptive, operating only when sensory inputs are sufficiently robust to guarantee visibility. Converging correlational and causal evidence links these behavioral results with inhibitory center-surround mechanisms, namely those in cortical area MT. Spatial suppression is abnormally weak in several special populations, including the elderly and those with schizophrenia—a deficit that is evidenced by better-than-normal direction discriminations of large moving stimuli. Theoretical work shows that this abnormal weakening of spatial suppression should result in motion segregation deficits, but direct behavioral support of this hypothesis is lacking. Finally, I will argue that the ability to suppress information is a fundamental neural process that applies not only to perception but also to cognition in general. Supporting this argument, I will discuss recent research that shows individual differences in spatial suppression of motion signals strongly predict individual variations in IQ scores. PMID:26299386

  19. Ejector Noise Suppression with Auxiliary Jet Injection

    NASA Technical Reports Server (NTRS)

    Berman, Charles H.; Andersen, Otto P., Jr.

    1997-01-01

    An experimental program to reduce aircraft jet turbulence noise investigated the interaction of small auxiliary jets with a larger main jet. Significant reductions in the far field jet noise were obtained over a range of auxiliary jet pressures and flow rates when used in conjunction with an acoustically lined ejector. While the concept is similar to that of conventional ejector suppressors that use mechanical mixing devices, the present approach should improve thrust and lead to lower weight and less complex noise suppression systems since no hardware needs to be located in the main jet flow. A variety of auxiliary jet and ejector configurations and operating conditions were studied. The best conditions tested produced peak to peak noise reductions ranging from 11 to 16 dB, depending on measurement angle, for auxiliary jet mass flows that were 6.6% of the main jet flow with ejectors that were 8 times the main jet diameter in length. Much larger reductions in noise were found at the original peak frequencies of the unsuppressed jet over a range of far field measurement angles.

  20. Harnessing Regulatory T cells to Suppress Asthma

    PubMed Central

    Thorburn, Alison N.; Hansbro, Philip M.

    2010-01-01

    Regulatory T cells (Tregs) play an essential role in maintaining the homeostatic balance of immune responses. Asthma is an inflammatory condition of the airways that is driven by dysregulated immune responses toward normally innocuous antigens. Individuals with asthma have fewer and less functional Tregs, which may lead to uncontrolled effector cell responses and promote proasthmatic responses of T helper type 2, T helper 17, natural killer T, antigen-presenting, and B cells. Tregs have the capacity to either directly or indirectly suppress these responses. Hence, the induced expansion of functional Tregs in predisposed or individuals with asthma is a potential approach for the prevention and treatment of asthma. Infection by a number of micro-organisms has been associated with reduced prevalence of asthma, and many infectious agents have been shown to induce Tregs and reduce allergic airways disease in mouse models. The translation of the regulatory and therapeutic properties of infectious agents for use in asthma requires the identification of key modulatory components and the development and trial of effective immunoregulatory therapies. Further translational and clinical research is required for the induction of Tregs to be harnessed as a therapeutic strategy for asthma. PMID:20097830

  1. A Mathematical Model for Suppression Subtractive Hybridization

    PubMed Central

    Gadgil, Chetan; Rink, Anette; Beattie, Craig

    2002-01-01

    Suppression subtractive hybridization (SSH) is frequently used to unearth differentially expressed genes on a whole-genome scale. Its versatility is based on combining cDNA library subtraction and normalization, which allows the isolation of sequences of varying degrees of abundance and differential expression. SSH is a complex process with many adjustable parameters that affect the outcome of gene isolation.We present a mathematical model of SSH based on DNA hybridization kinetics for assessing the effect of various parameters to facilitate its optimization. We derive an equation for the probability that a particular differentially expressed species is successfully isolated and use this to quantify the effect of the following parameters related to the cDNA sample: (a) mRNA abundance; (b) partial sequence complementarity to other species; and (3) degree of differential expression. We also evaluate the effect of parameters related to the process, including: (a) reaction times; and (b) extent of driver excess used in the two hybridization reactions. The optimum set of process parameters for successful isolation of differentially expressed species depends on transcript abundance. We show that the reaction conditions have a significant effect on the occurrence of false-positives and formulate strategies to isolate specific subsets of differentially expressed genes. We also quantify the effect of non-specific hybridization on the false-positive results and present strategies for spiking cDNA sequences to address this problem. PMID:18629052

  2. Method for suppressing noise in measurements

    NASA Technical Reports Server (NTRS)

    Carson, Paul L. (Inventor); Madsen, Louis A. (Inventor); Leskowitz, Garett M. (Inventor); Weitekamp, Daniel P. (Inventor)

    2000-01-01

    Methods for suppressing noise in measurements by correlating functions based on at least two different measurements of a system at two different times. In one embodiment, a measurement operation is performed on at least a portion of a system that has a memory. A property of the system is measured during a first measurement period to produce a first response indicative of a first state of the system. Then the property of the system is measured during a second measurement period to produce a second response indicative of a second state of the system. The second measurement is performed after an evolution duration subsequent to the first measurement period when the system still retains a degree of memory of an aspect of the first state. Next, a first function of the first response is combined with a second function of the second response to form a second-order correlation function. Information of the system is then extracted from the second-order correlation function.

  3. 't Hooft suppression and holographic entropy

    NASA Astrophysics Data System (ADS)

    Kelly, William R.; Kuns, Kevin; Marolf, Donald

    2015-10-01

    Recent works have related the bulk first law of black hole mechanics to the first law of entanglement in a dual CFT. These are first order relations, and receive corrections for finite changes. In particular, the latter is naively expected to be accurate only for small changes in the quantum state. But when Newton's constant is small relative to the AdS scale, the former holds to good approximation even for classical perturbations that contain many quanta. This suggests that — for appropriate states — corrections to the first law of entanglement are suppressed by powers of N in CFTs whose correlators satisfy 't Hooft large- N power counting. We take first steps toward verifying that this is so by studying the large- N structure of the entropy of spatial regions for a class of CFT states motivate dby those created from the vacuum by acting with real-time single-trace sources. We show that 1 /N counting matches bulk predictions, though we require the effect of the source on the modular hamiltonian to be non-singular. The magnitude of our sources is ɛ N with ɛ fixed-but-small as N → ∞. Our results also provide a perturbative derivation — without relying on the replica trick — of the subleading Faulkner-Lewkowycz-Maldacena correction to the Ryu-Takayagi and Hubeny-Rangamani-Takayanagi conjectures at all orders in 1 /N.

  4. Contrast, induction, facilitation, suppression, and conservation1

    PubMed Central

    Allison, James

    1976-01-01

    Ten rats received all of their water in daily 1-hr sessions. Following a baseline phase in which lever and water spout were freely available throughout each session, subjects were trained to press the lever for water on mixed schedules composed of two alternating components. Each component gave access to water for a fixed cumulation of drinking time every time the rat cumulated a fixed amount of lever-pressing time. Changes in one component produced contrast and induction effects, both positive and negative, with respect to both lever pressing and drinking in the unchanged component. All schedules facilitated lever pressing relative to baseline. All schedules suppressed drinking relative to baseline, even though contingency sessions allowed ample time to perform the baseline amount of drinking. The entire pattern of results was predicted in quantitative detail by assuming that the total amount of a dimension apportioned to lever pressing and drinking is conserved between baseline and contingency sessions. Conservation theory was shown to predict several effects produced by simple fixed-ratio schedules, and was compared favorably with probability-differential (Premack, 1971) and response-deprivation (Timberlake and Allison, 1974) theory. PMID:16811902

  5. Ribavirin efficiently suppresses porcine nidovirus replication.

    PubMed

    Kim, Youngnam; Lee, Changhee

    2013-01-01

    Porcine reproductive and respiratory syndrome virus (PRRSV) and porcine epidemic diarrhea virus (PEDV) are porcine nidoviruses that represent emerging viral pathogens causing heavy economic impacts on the swine industry. Although ribavirin is a well-known antiviral drug against a broad range of both DNA and RNA viruses in vitro, its inhibitory effect and mechanism of action on porcine nidovirus replication remains to be elucidated. Therefore, the present study was conducted to determine whether ribavirin suppresses porcine nidovirus infection. Our results demonstrated that ribavirin treatment dose-dependently inhibited the replication of both nidoviruses. The antiviral activity of ribavirin on porcine nidovirus replication was found to be primarily exerted at early times post-infection. Treatment with ribavirin resulted in marked reduction of viral genomic and subgenomic RNA synthesis, viral protein expression, and progeny virus production in a dose-dependent manner. Investigations into the mechanism of action of ribavirin against PRRSV and PEDV revealed that the addition of guanosine to the ribavirin treatment significantly reversed the antiviral effects, suggesting that depletion of the intracellular GTP pool by inhibiting IMP dehydrogenase may be essential for ribavirin activity. Further sequencing analysis showed that the mutation frequency in ribavirin-treated cells was similar to that in untreated cells, indicating that ribavirin did not induce error-prone replication. Taken together, our data indicate that ribavirin might not only be a good therapeutic agent against porcine nidovirus, but also a potential candidate to be evaluated against other human and animal coronaviruses.

  6. Clutter suppression interferometry system design and processing

    NASA Astrophysics Data System (ADS)

    Knight, Chad; Deming, Ross; Gunther, Jake

    2015-05-01

    Clutter suppression interferometry (CSI) has received extensive attention due to its multi-modal capability to detect slow-moving targets, and concurrently form high-resolution synthetic aperture radar (SAR) images from the same data. The ability to continuously augment SAR images with geo-located ground moving target indicators (GMTI) provides valuable real-time situational awareness that is important for many applications. CSI can be accomplished with minimal hardware and processing resources. This makes CSI a natural candidate for applications where size, weight and power (SWaP) are constrained, such as unmanned aerial vehicles (UAVs) and small satellites. This paper will discuss the theory for optimal CSI system configuration focusing on sparse time-varying transmit and receive array manifold due to SWaP considerations. The underlying signal model will be presented and discussed as well as the potential benefits that a sparse time-varying transmit receive manifold provides. The high-level processing objectives will be detailed and examined on simulated data. Then actual SAR data collected with the Space Dynamic Laboratory (SDL) FlexSAR radar system will be analyzed. The simulated data contrasted with actual SAR data helps illustrate the challenges and limitations found in practice vs. theory. A new novel approach incorporating sparse signal processing is discussed that has the potential to reduce false- alarm rates and improve detections.

  7. The SSM with Suppressed SUSY Charge

    NASA Astrophysics Data System (ADS)

    Dixon, John A.

    2016-10-01

    The concept of Suppressed SUSY Charge, introduced in a recent Letter, is used here to assemble a new version of the SSM. This new SSM has no need for Squarks or Sleptons. It does not need spontaneous breaking of SUSY, so that the cosmological constant problem does not arise (at least at tree level). It mimics the usual non-supersymmetric Standard Model very well, and the absence of large flavour changing neutral currents is natural. There is no need for a hidden sector, or a messenger sector, or explicit 'soft' breaking of SUSY. Spontaneous Gauge Symmetry Breaking from SU (3) × SU (2) × U (1) to SU (3) × U (1) in the model assembled here implies the existence of two new very heavy Higgs Bosons with mass 13.4 TeV, slightly smaller than the energy of the LHC at 14 TeV. There is also a curious set of Gauginos and Higgsinos which have exactly the same masses as the Higgs and Gauge Bosons. These do not couple to the Quarks and Leptons, except through the Higgs and Gauge Bosons. As it stands, this model probably gives rise to too many W+ decays to be consistent with experiment. The Feynman loop expansion of this theory also needs further examination.

  8. Heavy quarkonium suppression in a fireball

    SciTech Connect

    Escobedo, Miguel Ángel

    2016-01-22

    The dissociation of heavy quarkonium seen in heavy-ion collisions is a phenomena that allows to extract information of the produced thermal medium. This was believed to be due to the screening of the static potential but recently perturbative computations and some lattice studies have pointed out the possibility of having an imaginary part of the potential that would also contribute to dissociation. In recent years a program to study heavy quarkonium with the use of non-relativistic effective field theories (EFTs) has been started, this allows to make the computations in a more systematic way by defining a more suitable power counting and making it more difficult to miss necessary resummations. However until now these studies have been done assuming thermal equilibrium. In this work we will discuss what happens in the EFT formalism when heavy quarkonium is in a medium that is not in thermal equilibrium and what is the expected suppression when a medium with a time dependent effective temperature that follows Bjorken evolution is considered. This will be done adapting previous results from different temperature regimes.

  9. Growth suppression in the Trichuris dysentery syndrome.

    PubMed

    Cooper, E S; Bundy, D A; MacDonald, T T; Golden, M H

    1990-04-01

    The Trichuris Dysentery Syndrome (Ramsey, 1962) is an insidious, chronic condition which has clinical features similar to Crohn's ileocolitis and ulcerative colitis, diseases similarly associated with growth retardation. The attained heights and weights of 19 children at the time of diagnosis of intens, -2.4 Standard Deviation (Z) scores from the Tanner-Whitehouse median with weight, adjusted for height-age, -1.3 Z. We present data on the growth velocities of 11 of the children in the half-year following worm expulsion by mebendazole. These children returned to their home environments without food supplementation or close follow-up, but showed an average height velocity of +5.5 Z and weight velocity (for height-age) of +2.4 Z. Of 8 children with unequivocal height spurts only 3 had any weight spurt. We suggest that the pattern of catch-up growth points to the existence of some specific link between allergy or inflammation in the lower intestinal tract and suppression of linear growth, rather than to stunting due to general deprivation and undernutrition.

  10. Evolution of cancer suppression as revealed by mammalian comparative genomics.

    PubMed

    Tollis, Marc; Schiffman, Joshua D; Boddy, Amy M

    2017-02-02

    Cancer suppression is an important feature in the evolution of large and long-lived animals. While some tumor suppression pathways are conserved among all multicellular organisms, others mechanisms of cancer resistance are uniquely lineage specific. Comparative genomics has become a powerful tool to discover these unique and shared molecular adaptations in respect to cancer suppression. These findings may one day be translated to human patients through evolutionary medicine. Here, we will review theory and methods of comparative cancer genomics and highlight major findings of cancer suppression across mammals. Our current knowledge of cancer genomics suggests that more efficient DNA repair and higher sensitivity to DNA damage may be the key to tumor suppression in large or long-lived mammals.

  11. Active flutter suppression - Control system design and experimental validation

    NASA Technical Reports Server (NTRS)

    Waszak, Martin R.; Srinathkumar, S.

    1991-01-01

    The synthesis and experimental validation of an active flutter suppression controller for the Active Flexible Wing wind-tunnel model is presented. The design is accomplished with traditional root locus and Nyquist methods using interactive computer graphics tools and with extensive use of simulation-based analysis. The design approach uses a fundamental understanding of the flutter mechanism to formulate a simple controller structure to meet stringent design specifications. Experimentally, the flutter suppression controller succeeded in simultaneous suppression of two flutter modes, significantly increasing the flutter dynamic pressure despite errors in flutter dynamic pressure and flutter frequency in the mathematical model. The flutter suppression controller was also successfully operated in combination with a roll maneuver controller to perform flutter suppression during rapid rolling maneuvers.

  12. Physical work causes suppression of ovarian function in women.

    PubMed Central

    Jasieńska, G; Ellison, P T

    1998-01-01

    The suppression of reproductive function is known to occur in women engaging in activities that require high energetic expenses, such as sport participation and subsistence work. It is still unclear, however, if reproductive suppression is a response to high levels of energy expenditure, or only to the resulting state of negative energy balance. To our knowledge, this study provides the first evidence that work-related energy expenditure alone, without associated negative energy balance, can lead to the suppression of reproductive function in women. We document suppression of ovarian function expressed as lowered salivary progesterone levels in women from an agricultural community who work hard, but remain in neutral energy balance. We propose two alternative evolutionary explanations (the 'pre-emptive ovarian suppression' hypothesis and the 'constrained down-regulation' hypothesis) for the observed results. PMID:9802241

  13. An electrophysiological assessment of distractor suppression in visual search tasks.

    PubMed

    Mazza, Veronica; Turatto, Massimo; Caramazza, Alfonso

    2009-07-01

    We investigated whether the N2pc is unequivocally linked to distractor-suppression mechanisms, as is commonly assumed. According to the distractor-suppression account of the N2pc, no suppression, and thus no N2pc, should occur when homogeneous distractors help in selecting the target, such as when the target feature is unpredictable. Participants performed a simple detection or a finer discrimination on a singleton target, which had either a variable or a constant color. Contrary to the distractor-suppression account, an N2pc was present for both the variable and the constant conditions, and for both tasks. Additionally, target feature consistency correlated with earlier N2pc onsets relative to variable blocks. Both results indicate that the N2pc is not unequivocally linked to distractor-suppression mechanisms, but may index mechanisms involved in identifying and localizing relevant stimuli through enhancement of their features.

  14. Attenuating social affective learning effects with Memory Suppression manipulations.

    PubMed

    Molet, Mikael; Kosinski, Thierry; Craddock, Paul; Miguez, Gonzalo; Mash, Lisa E; Miller, Ralph R

    2016-02-01

    People can form opinions of other individuals based on information about their good or bad behavior. The present study investigated whether this affective learning might depend on memory links formed between initially neutral people and valenced information. First, participants viewed neutral faces paired with sentences describing prosocial or antisocial behaviors. Second, memory suppression manipulations with the potential to aid in the forgetting of valenced information were administered. Using the Think/No think paradigm, the effectiveness of four different suppression instructions was compared: Unguided Suppression, Guided Suppression, Distraction, and Thought Substitution. Overall, all the tasks appreciably reduced affective learning based on prosocial information, but only the Guided Suppression and Thought Substitution tasks reduced affective learning based on antisocial information. These results suggest that weakening the putative memory link between initially neutral people and valenced information can decrease the effect of learned associations on the evaluation of other people. We interpreted this as indicative that social affective learning may rely on declarative memories.

  15. Suppression of Antigen-Specific Lymphocyte Activation in Simulated Microgravity

    NASA Technical Reports Server (NTRS)

    Cooper, David; Pride, Michael W.; Brown, Eric L.; Risin, Diana; Pellis, Neal R.

    1999-01-01

    Various parameters of immune suppression are observed in astronauts during and after spaceflight, and in isolated immune cells in true and simulated microgravity. Specifically, polyclonal activation of T cells is severely suppressed in true and simulated microgravity. These recent findings with various polyclonal activators suggests a suppression of oligoclonal lymphocyte activation in microgravity. We utilized rotating wall vessel (RWV) bioreactors that simulate aspects of microgravity for cell cultures to analyze three models of antigen-specific activation. A mixed-lymphocyte reaction (MLR), as a model for a primary immune response; a tetanus toxoid (TT) response and a B. burgdorferi (Bb) response, as models of a secondary immune response, were all suppressed in the RWV bioreactor. Our findings confirm that the suppression of activation observed with polyclonal models also encompasses oligoclonal antigen-specific activation.

  16. Cytokine treatment of macrophage suppression of T cell activation.

    PubMed

    Silberman, Daniel; Bucknum, Amanda; Kozlowski, Megan; Matlack, Robin; Riggs, James

    2010-01-01

    High Mphi:T cell ratios suppress the immune response to the retroviral superantigen Mls by IFNgamma-triggered production of the arg- and trp-consuming enzymes iNOS and IDO. Attempts to reverse suppression by treatment with pro-inflammatory cytokines revealed that IL-6 improved the T cell response to Mls and the pro-hematopoietic cyokines IL-3 and GM-CSF increased suppression. GM-CSF treatment increased Mphi expression of CD80, a ligand for the immune suppressive B7H1 and CTLA-4 receptors. These results illustrate potential strategies for reversing the suppression of cell-mediated immunity characteristic of the high Mphi:T cell ratios found in many tumors.

  17. The role of suppression in figurative language comprehension✩

    PubMed Central

    Gemsbacher, Morton Ann; Robertson, Rachel R.W.

    2014-01-01

    In this paper, we describe the crucial role that suppression plays in many aspects of language comprehension. We define suppression as a general, cognitive mechanism, the purpose of which is to attenuate the interference caused by the activation of extraneous, unnecessary, or inappropriate information. We illustrate the crucial role that suppression plays in general comprehension by reviewing numerous experiments. These experiments demonstrate that suppression attenuates interference during lexical access (how word meanings are ‘accessed’), anaphoric reference (how referents for anaphors, like pronouns, are computed), cataphoric reference (how concepts that are marked by devices, such as spoken stress, gain a privileged status), syntactic parsing (how grammatical forms of sentences are decoded), and individual differences in (adult) language comprehension skill. We also review research that suggests that suppression plays a crucial role in the understanding of figurative language, in particular, metaphors, idioms, and proverbs. PMID:25520540

  18. Surround suppression and sparse coding in visual and barrel cortices

    PubMed Central

    Sachdev, Robert N. S.; Krause, Matthew R.; Mazer, James A.

    2012-01-01

    During natural vision the entire retina is stimulated. Likewise, during natural tactile behaviors, spatially extensive regions of the somatosensory surface are co-activated. The large spatial extent of naturalistic stimulation means that surround suppression, a phenomenon whose neural mechanisms remain a matter of debate, must arise during natural behavior. To identify common neural motifs that might instantiate surround suppression across modalities, we review models of surround suppression and compare the evidence supporting the competing ideas that surround suppression has either cortical or sub-cortical origins in visual and barrel cortex. In the visual system there is general agreement lateral inhibitory mechanisms contribute to surround suppression, but little direct experimental evidence that intracortical inhibition plays a major role. Two intracellular recording studies of V1, one using naturalistic stimuli (Haider et al., 2010), the other sinusoidal gratings (Ozeki et al., 2009), sought to identify the causes of reduced activity in V1 with increasing stimulus size, a hallmark of surround suppression. The former attributed this effect to increased inhibition, the latter to largely balanced withdrawal of excitation and inhibition. In rodent primary somatosensory barrel cortex, multi-whisker responses are generally weaker than single whisker responses, suggesting multi-whisker stimulation engages similar surround suppressive mechanisms. The origins of suppression in S1 remain elusive: studies have implicated brainstem lateral/internuclear interactions and both thalamic and cortical inhibition. Although the anatomical organization and instantiation of surround suppression in the visual and somatosensory systems differ, we consider the idea that one common function of surround suppression, in both modalities, is to remove the statistical redundancies associated with natural stimuli by increasing the sparseness or selectivity of sensory responses. PMID:22783169

  19. Growth characteristics of a weed-suppressive indica x non-suppressive tropical japonica rice mapping population

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The indica rice cultivar, PI 312777, can be highly productive as well as suppressive to C4 grass species such as barnyardgrass (Echinochloa crus-galli). A recombinant inbred line (RIL) mapping population was developed using single seed descent from a cross between ‘Katy’ (non-weed-suppressive) and ...

  20. Using Correlated Photons to Suppress Background Noise

    NASA Technical Reports Server (NTRS)

    Jackson, Deborah; Hockney, George; Dowling, Jonathan

    2003-01-01

    A proposed method of suppressing the effect of background noise in an optical communication system would exploit the transmission and reception of correlated photons at the receiver. The method would not afford any advantage in a system in which performance is limited by shot noise. However, if the performance of the system is limited by background noise (e.g., sunlight in the case of a free-space optical communication system or incoherently scattered in-band photons in the case of a fiber-optic communication system), then the proposed method could offer an advantage: the proposed method would make it possible to achieve a signal-to-noise ratio (S/N) significantly greater than that of an otherwise equivalent background- noise-limited optical communication system based on the classical transmission and reception of uncorrelated photons. The figure schematically depicts a classical optical-communication system and a system according to the proposed method. In the classical system, a modulated laser beam is transmitted along an optical path to a receiver, the optics of which include a narrow-band-pass filter that suppresses some of the background noise. A photodetector in the receiver detects the laser-beam and background photons, most or all of which are uncorrelated. In the proposed system, correlated photons would be generated at the transmitter by making a modulated laser beam pass through a nonlinear parametric down-conversion crystal. The sum of frequencies of the correlated photons in each pair would equal the frequency of the incident photon from which they were generated. As in the classical system, the correlated photons would travel along an optical path to a receiver, where they would be band-pass filtered and detected. Unlike in the classical system, the photodetector in the receiver in this system would be one that intrinsically favors the detection of pairs of correlated photons over the detection of uncorrelated photons. Even though there would be no

  1. Suppression of fibroblast proliferation by oral spirochetes.

    PubMed Central

    Boehringer, H; Taichman, N S; Shenker, B J

    1984-01-01

    Soluble sonic extracts of several strains of Treponema denticola and Treponema vincentii were examined for their abilities to alter proliferation of both murine and human fibroblasts. We found that sonic extracts of all tested strains of T. denticola caused a dose-dependent inhibition of murine and human fibroblast proliferation when assessed by both DNA synthesis ([3H]thymidine incorporation) and direct cell counts. T. vincentii had only a minimal inhibitory effect at comparable doses. No inhibition was observed when sonic extracts were added simultaneously with [3H]thymidine, indicating that suppression was not due to the presence of excessive amounts of cold thymidine in the extract, nonspecific effects on thymidine utilization by the cells (transport and incorporation), or degradation of label. RNA ([3H]uridine incorporation) and protein ([3H]leucine incorporation) synthesis were similarly altered after exposure to the T. denticola sonic extracts. There was no effect on cell viability as measured by trypan blue exclusion. Inhibition could be reversed by extensive washing of the cells within the first few hours of exposure to sonic extracts. Preliminary characterization and purification indicated that the inhibitory factor(s) is not endotoxin since it is heat labile, and elutes in a single, well-defined peak on a Sephadex G-150 chromatography column corresponding to a molecular weight of approximately 50,000. Since oral spirochetes have been implicated in the pathogenesis of periodontal disorders, it is possible that they contribute to the disease process by inhibition of fibroblast growth and therefore may, at least in part, account for the loss of collagen seen in diseased tissue. PMID:6735466

  2. Online fluorescence suppression in modulated Raman spectroscopy.

    PubMed

    De Luca, Anna Chiara; Mazilu, Michael; Riches, Andrew; Herrington, C Simon; Dholakia, Kishan

    2010-01-15

    Label-free chemical characterization of single cells is an important aim for biomedical research. Standard Raman spectroscopy provides intrinsic biochemical markers for noninvasive analysis of biological samples but is often hindered by the presence of fluorescence background. In this paper, we present an innovative modulated Raman spectroscopy technique to filter out the Raman spectra from the fluorescence background. The method is based on the principle that the fluorescence background does not change whereas the Raman scattering is shifted by the periodical modulation of the laser wavelength. Exploiting this physical property and importantly the multichannel lock-in detection of the Raman signal, the modulation technique fulfills the requirements of an effective fluorescence subtraction method. Indeed, once the synchronization and calibration procedure is performed, minimal user intervention is required, making the method online and less time-consuming than the other fluorescent suppression methods. We analyze the modulated Raman signal and shifted excitation Raman difference spectroscopy (SERDS) signal of 2 mum-sized polystyrene beads suspended in a solution of fluorescent dye as a function of modulation rate. We show that the signal-to-noise ratio of the modulated Raman spectra at the highest modulation rate is 3 times higher than the SERDS one. To finally evaluate the real benefits of the modulated Raman spectroscopy, we apply our technique to Chinese hamster ovary cells (CHO). Specifically, by analyzing separate spectra from the membrane, cytoplasm, and nucleus of CHO cells, we demonstrate the ability of this method to obtain localized sensitive chemical information from cells, away from the interfering fluorescence background. In particular, statistical analysis of the Raman data and classification using PCA (principal component analysis) indicate that our method allows us to distinguish between different cell locations with higher sensitivity and

  3. Suppression of Insulin Production and Secretion by a Decretin Hormone

    PubMed Central

    Alfa, Ronald W.; Park, Sangbin; Skelly, Kathleen-Rose; Poffenberger, Gregory; Jain, Nimit; Gu, Xueying; Kockel, Lutz; Wang, Jing; Liu, Yinghua; Powers, Alvin C.; Kim, Seung K.

    2015-01-01

    SUMMARY Decretins, hormones induced by fasting that suppress insulin production and secretion, have been postulated from classical human metabolic studies. From genetic screens, we identified Drosophila Limostatin (Lst), a peptide hormone that suppresses insulin secretion. Lst is induced by nutrient restriction in gut-associated endocrine cells. limostatin deficiency led to hyperinsulinemia, hypoglycemia and excess adiposity. A conserved 15-residue polypeptide encoded by limostatin suppressed secretion by insulin-producing cells. Targeted knockdown of CG9918, a Drosophila orthologue of Neuromedin U receptors (NMUR), in insulin-producing cells phenocopied limostatin deficiency, and attenuated insulin suppression by purified Lst, suggesting CG9918 encodes an Lst receptor. NMUR1 is expressed in islet β-cells, and purified NMU suppresses insulin secretion from human islets. A human mutant NMU variant that co-segregates with familial early-onset obesity and hyperinsulinemia fails to suppress insulin secretion. We propose Lst as an index member of an ancient hormone class called decretins, which suppress insulin output. PMID:25651184

  4. fMRI repetition suppression: neuronal adaptation or stimulus expectation?

    PubMed

    Larsson, Jonas; Smith, Andrew T

    2012-03-01

    Measurements of repetition suppression with functional magnetic resonance imaging (fMRI adaptation) have been used widely to probe neuronal population response properties in human cerebral cortex. fMRI adaptation techniques assume that fMRI repetition suppression reflects neuronal adaptation, an assumption that has been challenged on the basis of evidence that repetition-related response changes may reflect unrelated factors, such as attention and stimulus expectation. Specifically, Summerfield et al. (Summerfield C, Trittschuh EH, Monti JM, Mesulam MM, Egner T. 2008. Neural repetition suppression reflects fulfilled perceptual expectations. Nat Neurosci. 11:1004-1006) reported that the relative frequency of stimulus repetitions and non-repetitions influenced the magnitude of repetition suppression in the fusiform face area, suggesting that stimulus expectation accounted for most of the effect of repetition. We confirm that stimulus expectation can significantly influence fMRI repetition suppression throughout visual cortex and show that it occurs with long as well as short adaptation durations. However, the effect was attention dependent: When attention was diverted away from the stimuli, the effects of stimulus expectation completely disappeared. Nonetheless, robust and significant repetition suppression was still evident. These results suggest that fMRI repetition suppression reflects a combination of neuronal adaptation and attention-dependent expectation effects that can be experimentally dissociated. This implies that with an appropriate experimental design, fMRI adaptation can provide valid measures of neuronal adaptation and hence response specificity.

  5. Suppression of insulin production and secretion by a decretin hormone.

    PubMed

    Alfa, Ronald W; Park, Sangbin; Skelly, Kathleen-Rose; Poffenberger, Gregory; Jain, Nimit; Gu, Xueying; Kockel, Lutz; Wang, Jing; Liu, Yinghua; Powers, Alvin C; Kim, Seung K

    2015-02-03

    Decretins, hormones induced by fasting that suppress insulin production and secretion, have been postulated from classical human metabolic studies. From genetic screens, we identified Drosophila Limostatin (Lst), a peptide hormone that suppresses insulin secretion. Lst is induced by nutrient restriction in gut-associated endocrine cells. limostatin deficiency led to hyperinsulinemia, hypoglycemia, and excess adiposity. A conserved 15-residue polypeptide encoded by limostatin suppressed secretion by insulin-producing cells. Targeted knockdown of CG9918, a Drosophila ortholog of Neuromedin U receptors (NMURs), in insulin-producing cells phenocopied limostatin deficiency and attenuated insulin suppression by purified Lst, suggesting CG9918 encodes an Lst receptor. NMUR1 is expressed in islet β cells, and purified NMU suppresses insulin secretion from human islets. A human mutant NMU variant that co-segregates with familial early-onset obesity and hyperinsulinemia fails to suppress insulin secretion. We propose Lst as an index member of an ancient hormone class called decretins, which suppress insulin output.

  6. Criteria for Neoclassical Tearing Modes Suppression in KSTAR

    NASA Astrophysics Data System (ADS)

    Park, Y. S.; Hwang, Y. S.

    2007-11-01

    In KSTAR, neoclassical tearing modes(NTMs) will be suppressed by using 170GHz electron cyclotron current drive(ECCD) system with steering mirrors that align the current deposition to NTM locations. As an initial stage of NTM suppression study, 1 MW ECCD power will be used to suppress m/n = 3/2 and 2/1 NTMs. To confirm the feasibility of successful suppression of the modes under the proposed KSTAR environment, modified Rutherford equation(MRE) which encapsulates stability of NTMs is constructed for the target equilibrium of KSTAR. The geometric coefficients in MRE are obtained by comparing saturated sizes of NTMs from ISLAND code [1] with the amounts of local bootstrap currents from ONETWO. Parameters related to the operation of ECCD are analyzed by TORAY-GA linear ray-tracing code. Due to the small ECCD power available at the initial stage of KSTAR, condition of the optimum ECCD modulation is considered in the analysis to maximize suppression performance. From the analyses, criteria such as the minimum ECCD power required for complete suppression of the modes and the optimum conditions of EC wave launch angle and modulation duty factor are derived for the successful NTM suppression in KSTAR. [1] C.N. Nguyen, G. Bateman and A.H. Kritz, Phys. Plasmas 11 3460 (2004)

  7. The proposed role of suppression in simultaneous interpretation

    PubMed Central

    Gernsbacher, Morton Ann; Shlesinger, Miriam

    2014-01-01

    In this paper we suggest that the cognitive mechanism of suppression attenuates interference in many language comprehension phenomena, and is particularly crucial when comprehension must share processing capacity with other cognitive tasks, as is manifestly the case in simultaneous interpreting. During lexical access, the mechanism of suppression attenuates the interference caused by the activation of other lexical information, such as the inappropriate meanings of homonyms. During anaphoric reference, the mechanism of suppression attenuates the interference caused by the activation of other potential referents. In this way, the referent to which the anaphor does refer becomes the most activated concept. During syntactic parsing, the mechanism of suppression attenuates the interference caused by a previous syntactic form. During metaphor comprehension, the mechanism of suppression attenuates the interference caused by a literal interpretation. During inferencing, the mechanism of suppression attenuates the interference caused by an initial but inappropriate inference. We propose therefore that suppression — a general, cognitive mechanism that attenuates interference — plays a crucial role in language comprehension and simultaneous interpretation. PMID:25520570

  8. Definition of experiments to investigate fire suppressants in microgravity

    NASA Technical Reports Server (NTRS)

    Reuther, James J.

    1990-01-01

    Defined and justified here are the conceptual design and operation of a critical set of experiments expected to yield information on suppressants and on suppressant delivery systems under realistic spacecraft-fire conditions (smoldering). Specific experiment parameters are provided on the solid fuel (carbon), oxidants (habitable spacecraft atmospheres), fuel/oxidant supply, mixing mode, and rate (quiescent and finite; ventilated and replenishable), ignition mode, event, and reignition tendency, fire-zone size, fire conditions, lifetime, and consequences (toxicity), suppressants (CO2, H2O, N2) and suppressant delivery systems, and diagnostics. Candidate suppressants were identified after an analysis of how reduced gravity alters combustion, and how these alterations may influence the modes, mechanisms, and capacities of terrestrial agents to suppress unwanted combustion, or fire. Preferred spacecraft suppression concepts included the local, near-quiescent application of a gas, vapor, or mist that has thermophysical fire-suppression activity and is chemically inert under terrestrial (normal gravity) combustion conditions. The scale, number, and duration (about 1 hour) of the proposed low-gravity experiments were estimated using data not only on the limitations imposed by spacecraft-carrier (Shuttle or Space Station Freedom) accommodations, but also data on the details and experience of standardized smolder-suppression experiments at normal gravity. Deliberately incorporated into the conceptual design was sufficient interchangeability for the prototype experimental package to fly either on Shuttle now or Freedom later. This flexibility is provided by the design concept of up to 25 modular fuel canisters within a containment vessel, which permits both integration into existing low-gravity in-space combustion experiments and simultaneous testing of separate experiments to conserve utilities and time.

  9. Effectors from Wheat Rust Fungi Suppress Multiple Plant Defense Responses.

    PubMed

    Ramachandran, Sowmya R; Yin, Chuntao; Kud, Joanna; Tanaka, Kiwamu; Mahoney, Aaron K; Xiao, Fangming; Hulbert, Scot H

    2017-01-01

    Fungi that cause cereal rust diseases (genus Puccinia) are important pathogens of wheat globally. Upon infection, the fungus secretes a number of effector proteins. Although a large repository of putative effectors has been predicted using bioinformatic pipelines, the lack of available high-throughput effector screening systems has limited functional studies on these proteins. In this study, we mined the available transcriptomes of Puccinia graminis and P. striiformis to look for potential effectors that suppress host hypersensitive response (HR). Twenty small (<300 amino acids), secreted proteins, with no predicted functions were selected for the HR suppression assay using Nicotiana benthamiana, in which each of the proteins were transiently expressed and evaluated for their ability to suppress HR caused by four cytotoxic effector-R gene combinations (Cp/Rx, ATR13/RPP13, Rpt2/RPS-2, and GPA/RBP-1) and one mutated R gene-Pto(Y207D). Nine out of twenty proteins, designated Shr1 to Shr9 (suppressors of hypersensitive response), were found to suppress HR in N. benthamiana. These effectors varied in the effector-R gene defenses they suppressed, indicating these pathogens can interfere with a variety of host defense pathways. In addition to HR suppression, effector Shr7 also suppressed PAMP-triggered immune response triggered by flg22. Finally, delivery of Shr7 through Pseudomonas fluorescens EtHAn suppressed nonspecific HR induced by Pseudomonas syringae DC3000 in wheat, confirming its activity in a homologous system. Overall, this study provides the first evidence for the presence of effectors in Puccinia species suppressing multiple plant defense responses.

  10. Suppression of NF-κB Activation By Gentian Violet Promotes Osteoblastogenesis and Suppresses Osteoclastogenesis

    PubMed Central

    Yamaguchi, M.; Vikulina, T.; Arbiser, J.L.; Weitzmann, M.N.

    2015-01-01

    Skeletal mass is regulated by the coordinated action of bone forming osteoblasts and bone resorbing osteoclasts. Accelerated rates of bone resorption relative to bone formation lead to net bone loss and the development of osteoporosis, a devastating disease that predisposes the skeleton to fractures. Bone fractures are associated with significant morbidity and in the case of hip fractures, high mortality. Gentian violet (GV), a cationic triphenylmethane dye, has long been used as an antifungal and antibacterial agent and is presently under investigation as a potential chemotherapeutic and antiangiogenic agent. However, effects on bone cells have not been previously reported and the mechanisms of action of GV, are poorly understood. In this study we show that GV suppresses receptor activator of NF-κB ligand (RANKL)-induced differentiation of RAW264.7 osteoclast precursors into mature osteoclasts, but paradoxically stimulates the differentiation of MC3T3 cells into mineralizing osteoblasts. These actions stem from the capacity of GV to suppress activation of the nuclear factor kappa B (NF-κB) signal transduction pathway that is required for osteoclastogenesis, but inhibitory to osteoblast differentiation and activity. Our data reveal that GV is an inhibitor of NF-κB activation and may hold promise for modulation of bone turnover to promote a balance between bone formation and bone resorption, favorable to gain of bone mass. PMID:25056540

  11. Burst suppression electroencephalogram with mushroom poisoning, Amanita pantherina

    PubMed Central

    Ogawa, Yuka; Sato, Hiromasa; Yamamoto, Motoyoshi; Tada, Hiroyuki; Hashimoto, Takao

    2015-01-01

    We report on a patient with Amanita pantherina poisoning who showed a burst suppression pattern on electroencephalography during a comatose state. The patient recovered without sequelae a week after ingestion. Burst suppression pattern is defined as alternating bursts and periods of electrical silence, and it is associated with comatose states of various causes. The major toxins contained in A. pantherina are ibotenic acid, an excitatory amino acid at the glutamate receptors, and muscimol, an agonist of the gamma-aminobutyric acid receptors. Alteration of the synaptic transmission in the central nervous system by these toxins may lead to a burst suppression pattern. PMID:26543811

  12. Local cortical dynamics of burst suppression in the anaesthetized brain.

    PubMed

    Lewis, Laura D; Ching, Shinung; Weiner, Veronica S; Peterfreund, Robert A; Eskandar, Emad N; Cash, Sydney S; Brown, Emery N; Purdon, Patrick L

    2013-09-01

    Burst suppression is an electroencephalogram pattern that consists of a quasi-periodic alternation between isoelectric 'suppressions' lasting seconds or minutes, and high-voltage 'bursts'. It is characteristic of a profoundly inactivated brain, occurring in conditions including hypothermia, deep general anaesthesia, infant encephalopathy and coma. It is also used in neurology as an electrophysiological endpoint in pharmacologically induced coma for brain protection after traumatic injury and during status epilepticus. Classically, burst suppression has been regarded as a 'global' state with synchronous activity throughout cortex. This assumption has influenced the clinical use of burst suppression as a way to broadly reduce neural activity. However, the extent of spatial homogeneity has not been fully explored due to the challenges in recording from multiple cortical sites simultaneously. The neurophysiological dynamics of large-scale cortical circuits during burst suppression are therefore not well understood. To address this question, we recorded intracranial electrocorticograms from patients who entered burst suppression while receiving propofol general anaesthesia. The electrodes were broadly distributed across cortex, enabling us to examine both the dynamics of burst suppression within local cortical regions and larger-scale network interactions. We found that in contrast to previous characterizations, bursts could be substantially asynchronous across the cortex. Furthermore, the state of burst suppression itself could occur in a limited cortical region while other areas exhibited ongoing continuous activity. In addition, we found a complex temporal structure within bursts, which recapitulated the spectral dynamics of the state preceding burst suppression, and evolved throughout the course of a single burst. Our observations imply that local cortical dynamics are not homogeneous, even during significant brain inactivation. Instead, cortical and, implicitly

  13. Enhancement of Antigen-Specific Suppression by Muramyl Dipeptide

    PubMed Central

    Ferguson, Thomas A.; Krieger, Nancy J.; Pesce, Amadeo; Michael, J. Gabriel

    1983-01-01

    The effect of the synthetic adjuvant MDP (N-acetyl-muramyl-L-alanyl-D-isoglu-tamine) on the generation of antigen-specific suppression was investigated. Suppression of the anti-bovine serum albumin response, which was achieved by intravenous administration of a peptic fragment of the antigen, was greatly enhanced by simultaneous administration of MDP. Induction of suppression by a combination of bovine serum albumin fragments and MDP was found to be antigen specific and appeared to occur via the generation of antigen-specific suppressor T cells. PMID:6187686

  14. Suppression of Odorant Responses by Odorants in Olfactory Receptor Cells

    NASA Astrophysics Data System (ADS)

    Kurahashi, Takashi; Lowe, Graeme; Gold, Geoffrey H.

    1994-07-01

    Odorants activate an inward current in vertebrate olfactory receptor cells. Here it is shown, in receptor cells from the newt, that odorants can also suppress this current, by a mechanism that is distinct from inhibition and adaptation. Suppression provides a simple explanation for two seemingly unrelated phenomena: the anomalously long latency of olfactory transduction and the existence of an "off response" at the end of a prolonged stimulus. Suppression may influence the perception of odorants by masking odorant responses and by sharpening the odorant specificities of single cells.

  15. Suppression of strike-slip fault systems

    NASA Astrophysics Data System (ADS)

    Curren, I. S.

    2012-12-01

    depth. Selected areas on Earth with anomalously undeveloped strike-slip faulting where plate models would predict otherwise were compared with results from the analog model experiments in this study. Physical similarities between this model and Brothers Fault Zone (BFZ), Walker Lane (WL) and the South Iceland Seismic Zone (SISZ) imply that strike-slip faulting may be suppressed at the surface in these regions due to the presence of pre-existing structures. Filled circles show offset required for breakthrough faulting, empty circles denote lower limit of breakthrough. Triangles show clay offset as a fraction of box offset. Note that clays with pre-existing structures showed larger offsets although breakthrough did not occur.

  16. Fire retardant foams developed to suppress fuel fires

    NASA Technical Reports Server (NTRS)

    Fish, R.; Gilwee, W. J.; Parker, J. A.; Riccitiello, S. R.

    1968-01-01

    Heat insulating polyurethane foam retards and suppresses fuel fires. Uniformly dispersed in the foam is a halogenated polymer capable of splitting off hydrogen halide upon heating and charring of the polyurethane.

  17. High-precision buffer circuit for suppression of regenerative oscillation

    NASA Technical Reports Server (NTRS)

    Tripp, John S.; Hare, David A.; Tcheng, Ping

    1995-01-01

    Precision analog signal conditioning electronics have been developed for wind tunnel model attitude inertial sensors. This application requires low-noise, stable, microvolt-level DC performance and a high-precision buffered output. Capacitive loading of the operational amplifier output stages due to the wind tunnel analog signal distribution facilities caused regenerative oscillation and consequent rectification bias errors. Oscillation suppression techniques commonly used in audio applications were inadequate to maintain the performance requirements for the measurement of attitude for wind tunnel models. Feedback control theory is applied to develop a suppression technique based on a known compensation (snubber) circuit, which provides superior oscillation suppression with high output isolation and preserves the low-noise low-offset performance of the signal conditioning electronics. A practical design technique is developed to select the parameters for the compensation circuit to suppress regenerative oscillation occurring when typical shielded cable loads are driven.

  18. Multifunction tests of a frequency domain based flutter suppression system

    NASA Technical Reports Server (NTRS)

    Christhilf, David M.; Adams, William M., Jr.

    1992-01-01

    The process is described of analysis, design, digital implementation, and subsonic testing of an active control flutter suppression system for a full span, free-to-roll wind tunnel model of an advanced fighter concept. The design technique uses a frequency domain representation of the plant and used optimization techniques to generate a robust multi input/multi output controller. During testing in a fixed-in-roll configuration, simultaneous suppression of both symmetric and antisymmetric flutter was successfully shown. For a free-to-roll configuration, symmetric flutter was suppressed to the limit of the tunnel test envelope. During aggressive rolling maneuvers above the open-loop flutter boundary, simultaneous flutter suppression and maneuver load control were demonstrated. Finally, the flutter damping controller was reoptimized overnight during the test using combined experimental and analytical frequency domain data, resulting in improved stability robustness.

  19. Acoustic Flame Suppression Mechanics in a Microgravity Environment

    NASA Astrophysics Data System (ADS)

    Beisner, Eryn; Wiggins, Nathanial David; Yue, Kwok-Bun; Rosales, Miguel; Penny, Jeremy; Lockridge, Jarrett; Page, Ryan; Smith, Alexander; Guerrero, Leslie

    2015-06-01

    The following paper deals with acoustic flame suppression mechanics in a microgravity environment with measurements taken from an Arduino-based sensor system and validation of the technique. A Zippo lighter is ignited in microgravity and then displaced from the base of the flame and suppressed using surface interactions with single tone acoustic waves to extinguished the flame. The analysis of data collected shows that the acoustic flame suppression measurementtechniques are effective to finding qualitative differences in extinguishing in microgravity and normal gravity. Further, the results suggest that the suppression may be more effective in a microgravity environment than in a normal (1g) environment and may be a viable method of extinguishing fires during space flight.

  20. Acetonitrile Ion Suppression in Atmospheric Pressure Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Colizza, Kevin; Mahoney, Keira E.; Yevdokimov, Alexander V.; Smith, James L.; Oxley, Jimmie C.

    2016-11-01

    Efforts to analyze trace levels of cyclic peroxides by liquid chromatography/mass spectrometry gave evidence that acetonitrile suppressed ion formation. Further investigations extended this discovery to ketones, linear peroxides, esters, and possibly many other types of compounds, including triazole and menadione. Direct ionization suppression caused by acetonitrile was observed for multiple adduct types in both electrospray ionization and atmospheric pressure chemical ionization. The addition of only 2% acetonitrile significantly decreased the sensitivity of analyte response. Efforts to identify the mechanism were made using various nitriles. The ion suppression was reduced by substitution of an acetonitrile hydrogen with an electron-withdrawing group, but was exacerbated by electron-donating or steric groups adjacent to the nitrile. Although current theory does not explain this phenomenon, we propose that polar interactions between the various functionalities and the nitrile may be forming neutral aggregates that manifest as ionization suppression.

  1. Acetonitrile Ion Suppression in Atmospheric Pressure Ionization Mass Spectrometry.

    PubMed

    Colizza, Kevin; Mahoney, Keira E; Yevdokimov, Alexander V; Smith, James L; Oxley, Jimmie C

    2016-11-01

    Efforts to analyze trace levels of cyclic peroxides by liquid chromatography/mass spectrometry gave evidence that acetonitrile suppressed ion formation. Further investigations extended this discovery to ketones, linear peroxides, esters, and possibly many other types of compounds, including triazole and menadione. Direct ionization suppression caused by acetonitrile was observed for multiple adduct types in both electrospray ionization and atmospheric pressure chemical ionization. The addition of only 2% acetonitrile significantly decreased the sensitivity of analyte response. Efforts to identify the mechanism were made using various nitriles. The ion suppression was reduced by substitution of an acetonitrile hydrogen with an electron-withdrawing group, but was exacerbated by electron-donating or steric groups adjacent to the nitrile. Although current theory does not explain this phenomenon, we propose that polar interactions between the various functionalities and the nitrile may be forming neutral aggregates that manifest as ionization suppression. Graphical Abstract ᅟ.

  2. Breeding a super nematode for enhanced insect pest suppression

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Entomopathogenic nematodes in the genera Heterorhabditis and Steinernema are important regulators of natural insect populations, and are used commercially as biological control agents for pest suppression. Successful biocontrol applications depend on the introduced organism having an array of benef...

  3. Unnoticed intrusions: dissociations of meta-consciousness in thought suppression.

    PubMed

    Baird, Benjamin; Smallwood, Jonathan; Fishman, Daniel J F; Mrazek, Michael D; Schooler, Jonathan W

    2013-09-01

    The current research investigates the interaction between thought suppression and individuals' explicit awareness of their thoughts. Participants in three experiments attempted to suppress thoughts of a prior romantic relationship and their success at doing so was measured using a combination of self-catching and experience-sampling. In addition to thoughts that individuals spontaneously noticed, individuals were frequently caught engaging in thoughts of their previous partner at experience-sampling probes. Furthermore, probe-caught thoughts were: (i) associated with stronger decoupling of attention from the environment, (ii) more likely to occur under cognitive load, (iii) more frequent for individuals with a desire to reconcile, and (iv) associated with individual differences in the tendency to suppress thoughts. Together, these data suggest that individuals can lack meta-awareness that they have begun to think about a topic they are attempting to suppress, providing novel insight into the cognitive processes that are involved in attempting to control undesired mental states.

  4. Critical suppression of spin Seebeck effect by magnetic fields

    NASA Astrophysics Data System (ADS)

    Kikkawa, Takashi; Uchida, Ken-ichi; Daimon, Shunsuke; Qiu, Zhiyong; Shiomi, Yuki; Saitoh, Eiji

    2015-08-01

    The longitudinal spin Seebeck effect (LSSE) in Pt /Y3Fe5O12(YIG ) junction systems has been investigated at various magnetic fields and temperatures. We found that the LSSE voltage in a Pt/YIG-slab system is suppressed by applying high magnetic fields and this suppression is critically enhanced at low temperatures. The field-induced suppression of the LSSE in the Pt/YIG-slab system is too large at around room temperature to be explained simply by considering the effect of the Zeeman gap in magnon excitation. This result requires us to introduce a magnon-frequency-dependent mechanism into the scenario of LSSE; low-frequency magnons dominantly contribute to the LSSE. The magnetic field dependence of the LSSE voltage was observed to change by changing the thickness of YIG, suggesting that the thermospin conversion by the low-frequency magnons is suppressed in thin YIG films due to the long characteristic lengths of such magnons.

  5. Splash Suppression by Solvent Viscosity in Dense Suspension Impact

    NASA Astrophysics Data System (ADS)

    Zhang, Wendy; Dodge, Kevin; Peters, Ivo; Klein Schaarsberg, Martin; Jaeger, Heinrich

    2015-03-01

    When a dense suspension droplet impacts a hard surface, it will either break apart (``splash'') or remain in a compact configuration without ejecting any particles. We use experiments and discrete particle simulations in which relative particle motions are penalized by lubrication-flow drag to analyze the influence of solvent viscosity on splashing. We find that suspension splash is driven by particle inertia. It can be suppressed in 2 different ways. At low solvent viscosity, lubrication drag due to viscous flow has a negligible effect. Splash is suppressed by surface tension overcoming particle inertia. At high solvent viscosity, lubrication drag alone suppresses splashing. Because impact produces an expanding flow that stretches the suspension radially, suppression in the high-viscosity regime is largely accomplished by lubrication-flow drag preventing initially nearby particle pairs from separating fully. Energy dissipation by viscous flow during collisions plays a smaller role. Present Address: Physics of Fluids Group, University of Twente.

  6. Optical frequency tripling with improved suppression and sideband selection.

    PubMed

    Thakur, Manoj P; Medeiros, Maria C R; Laurêncio, Paula; Mitchell, John E

    2011-12-12

    A novel optical dispersion tolerant millimetre-wave radio-over-fibre system using optical frequency tripling technique with enhanced and selectable sideband suppression is demonstrated. The implementation utilises cascaded optical modulators to achieve either an optical single sideband (OSSB) or double sideband-suppressed carrier (DSB-SC) signal with high sideband suppression. Our analysis and simulation results indicate that the achievable suppression ratio of this configuration is only limited by other system factors such as optical noise and drifting of the operational conditions. The OSSB transmission system performance is assessed experimentally by the transport of 4 WiMax channels modulating a 10 GHz optical upconverted RF carrier as well as for optical frequency doubling and tripling. The 10 GHz and tripled carrier at 30 GHz are dispersion tolerant resulting both in an average relative constellation error (RCE) of -28.7 dB after 40 km of fibre.

  7. Probiotic Diversity Enhances Rhizosphere Microbiome Function and Plant Disease Suppression

    PubMed Central

    Hu, Jie; Friman, Ville-Petri; Gu, Shao-hua; Wang, Xiao-fang; Eisenhauer, Nico; Yang, Tian-jie; Ma, Jing; Shen, Qi-rong; Jousset, Alexandre

    2016-01-01

    ABSTRACT Bacterial communities associated with plant roots play an important role in the suppression of soil-borne pathogens, and multispecies probiotic consortia may enhance disease suppression efficacy. Here we introduced defined Pseudomonas species consortia into naturally complex microbial communities and measured the importance of Pseudomonas community diversity for their survival and the suppression of the bacterial plant pathogen Ralstonia solanacearum in the tomato rhizosphere microbiome. The survival of introduced Pseudomonas consortia increased with increasing diversity. Further, high Pseudomonas diversity reduced pathogen density in the rhizosphere and decreased the disease incidence due to both intensified resource competition and interference with the pathogen. These results provide novel mechanistic insights into elevated pathogen suppression by diverse probiotic consortia in naturally diverse plant rhizospheres. Ecologically based community assembly rules could thus play a key role in engineering functionally reliable microbiome applications. PMID:27965449

  8. Active Suppression Of Vibrations In Stirling-Cycle Coolers

    NASA Technical Reports Server (NTRS)

    Johnson, Bruce G.; Flynn, Frederick J.; Gaffney, Monique S.

    1995-01-01

    Report presents results of early research directed toward development of active control systems for suppression of vibrations in spacecraft Stirling-cycle cryocoolers. Researchers developed dynamical models of cryocooler compressor.

  9. 23. FIRE SUPPRESSION SYSTEM PIPE, 'GRINNELL VALVE', 'VICTROLIC COUPLING,' AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    23. FIRE SUPPRESSION SYSTEM PIPE, 'GRINNELL VALVE', 'VICTROLIC COUPLING,' AND ALARM AT THE REAR OF BAY NO. 5. - Barstow-Daggett Airport, Hangar Shed No. 4, 39500 National Trails Highway, Daggett, San Bernardino County, CA

  10. A model for tumor suppression using H-1 parvovirus.

    PubMed Central

    Telerman, A; Tuynder, M; Dupressoir, T; Robaye, B; Sigaux, F; Shaulian, E; Oren, M; Rommelaere, J; Amson, R

    1993-01-01

    A model system is proposed to investigate, at the molecular level, the pathways of tumor suppression. As a tool for the selection of cells with a suppressed phenotype, we used the H-1 parvovirus that preferentially kills various neoplastic cells. From the human K562 leukemia cells, we isolated a clone, KS, that is resistant to the cytopathic effect of the H-1 virus and displays a suppressed malignant phenotype. The suppressed malignancy and the cellular resistance to H-1 killing appear to depend on the activity of wild-type p53. Whereas the KS cells express wild-type p53, the protein is undetectable in the parental K562 cells. Experiments with p53 mutants suggest that wild-type p53, in its functionally intact state, contributes to the resistance against the cytopathic effect of H-1 parvovirus. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:8378352

  11. Acute self-suppression of corticosteroidogenesis in isolated adrenocortical cells.

    PubMed

    Carsia, R V; Malamed, S

    1979-10-01

    The relation between steroidogenesis induced by ACTH and that induced by exogenous concentrations of glucocorticoids was studied in isolated adrenocortical cells. Exogenous corticosterone and cortisol, in concentrations within the production capacity of the adrenal gland, suppressed steroidogenesis induced by ACTH in rat and beef cells, respectively. The precursors pregnenolone and progesterone enhanced steroidogenesis in both rat and beef cells. Aldosterone in rat cells and 17 beta-estradiol in rat and beef cells had little if any effect on steroidogenesis. Either suppression or stimulation by exogenous steroids was acute, that is, after 2-h incubation for rat cells and 1-h incubation for beef cells. A direct suppressive action of end product glucocorticoids is indicated. This observed self-suppression of adrenocortical cells suggests the existence of a mechanism for the find adjustment of steroidogenesis that operates in addition to the classical control exerted by the anterior pituitary.

  12. DETAIL VIEW OF THE SOUND SUPPRESSION SPRAY NOZZLE POSITIONED BETWEEN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL VIEW OF THE SOUND SUPPRESSION SPRAY NOZZLE POSITIONED BETWEEN THE TWO SRB EXHAUST OPENINGS - Cape Canaveral Air Force Station, Launch Complex 39, Mobile Launcher Platforms, Launcher Road, East of Kennedy Parkway North, Cape Canaveral, Brevard County, FL

  13. Suppression of translucent elongated structures: applications in chest radiography.

    PubMed

    Hogeweg, Laurens; Sanchez, Clara I; van Ginneken, Bram

    2013-11-01

    Projection images, such as those routinely acquired in radiological practice, are difficult to analyze because multiple 3-D structures superimpose at a single point in the 2-D image. Removal of particular superimposed structures may improve interpretation of these images, both by humans and by computers. This work therefore presents a general method to isolate and suppress structures in 2-D projection images. The focus is on elongated structures, which allows an intensity model of a structure of interest to be extracted using local information only. The model is created from profiles sampled perpendicular to the structure. Profiles containing other structures are detected and removed to reduce the influence on the model. Subspace filtering, using blind source separation techniques, is applied to separate the structure to be suppressed from other structures. By subtracting the modeled structure from the original image a structure suppressed image is created. The method is evaluated in four experiments. In the first experiment ribs are suppressed in 20 artificial radiographs simulated from 3-D lung computed tomography (CT) images. The proposed method with blind source separation and outlier detection shows superior suppression of ribs in simulated radiographs, compared to a simplified approach without these techniques. Additionally, the ability of three observers to discriminate between patches containing ribs and containing no ribs, as measured by the area under the receiver operating characteristic curve (AUC), reduced from 0.99-1.00 on original images to 0.75-0.84 on suppressed images. In the second experiment clavicles are suppressed in 253 chest radiographs. The effect of suppression on clavicle visibility is evaluated using the clavicle contrast and border response, showing a reduction of 78% and 34%, respectively. In the third experiment nodules extracted from CT were simulated close to the clavicles in 100 chest radiographs. It was found that after

  14. Robust control design techniques for active flutter suppression

    NASA Technical Reports Server (NTRS)

    Ozbay, Hitay; Bachmann, Glen R.

    1994-01-01

    In this paper, an active flutter suppression problem is studied for a thin airfoil in unsteady aerodynamics. The mathematical model of this system is infinite dimensional because of Theodorsen's function which is irrational. Several second order approximations of Theodorsen's function are compared. A finite dimensional model is obtained from such an approximation. We use H infinity control techniques to find a robustly stabilizing controller for active flutter suppression.

  15. Neuronal Networks during Burst Suppression as Revealed by Source Analysis

    PubMed Central

    Reinicke, Christine; Moeller, Friederike; Anwar, Abdul Rauf; Mideksa, Kidist Gebremariam; Pressler, Ronit; Deuschl, Günther; Stephani, Ulrich; Siniatchkin, Michael

    2015-01-01

    Introduction Burst-suppression (BS) is an electroencephalography (EEG) pattern consisting of alternant periods of slow waves of high amplitude (burst) and periods of so called flat EEG (suppression). It is generally associated with coma of various etiologies (hypoxia, drug-related intoxication, hypothermia, and childhood encephalopathies, but also anesthesia). Animal studies suggest that both the cortex and the thalamus are involved in the generation of BS. However, very little is known about mechanisms of BS in humans. The aim of this study was to identify the neuronal network underlying both burst and suppression phases using source reconstruction and analysis of functional and effective connectivity in EEG. Material/Methods Dynamic imaging of coherent sources (DICS) was applied to EEG segments of 13 neonates and infants with burst and suppression EEG pattern. The brain area with the strongest power in the analyzed frequency (1–4 Hz) range was defined as the reference region. DICS was used to compute the coherence between this reference region and the entire brain. The renormalized partial directed coherence (RPDC) was used to describe the informational flow between the identified sources. Results/Conclusion Delta activity during the burst phases was associated with coherent sources in the thalamus and brainstem as well as bilateral sources in cortical regions mainly frontal and parietal, whereas suppression phases were associated with coherent sources only in cortical regions. Results of the RPDC analyses showed an upwards informational flow from the brainstem towards the thalamus and from the thalamus to cortical regions, which was absent during the suppression phases. These findings may support the theory that a “cortical deafferentiation” between the cortex and sub-cortical structures exists especially in suppression phases compared to burst phases in burst suppression EEGs. Such a deafferentiation may play a role in the poor neurological outcome of

  16. Iridescence from photonic crystals and its suppression in butterfly scales

    PubMed Central

    Poladian, Leon; Wickham, Shelley; Lee, Kwan; Large, Maryanne C.J.

    2008-01-01

    Regular three-dimensional periodic structures have been observed in the scales of over half a dozen butterfly species. We compare several of these structures: we calculate their photonic bandgap properties; measure the angular variation of the reflection spectra; and relate the observed iridescence (or its suppression) to the structures. We compare the mechanisms for iridescence suppression in different species and conclude with some speculations about form, function, development and evolution. PMID:18980932

  17. Appetite suppressing pregnane glycosides from the roots of Cynanchum auriculatum.

    PubMed

    Liu, Shuangzhu; Chen, Zhenhua; Wu, Jian; Wang, Luoyi; Wang, Hongmin; Zhao, Weimin

    2013-09-01

    In the search for plant alternatives to Hoodia gordonii containing P57, a pregnane glycoside with potential appetite suppressant effect, the roots of Cynanchum auriculatum were investigated. As a result, 15 pregnane glycosides including nine never previously reported were isolated. Their structures were elucidated on the basis of extensive spectroscopic analyses and chemical methods. Appetite suppressant effect and body weight loss were observed when tested with the most abundant pregnane glycoside, wilfoside K1N, in an in vivo test with rats.

  18. Mode of ATM-dependent suppression of chromosome translocation

    SciTech Connect

    Yamauchi, Motohiro; Suzuki, Keiji; Oka, Yasuyoshi; Suzuki, Masatoshi; Kondo, Hisayoshi; Yamashita, Shunichi

    2011-12-09

    Highlights: Black-Right-Pointing-Pointer We addressed how ATM suppresses frequency of chromosome translocation. Black-Right-Pointing-Pointer We found ATM/p53-dependent G1 checkpoint suppresses translocation frequency. Black-Right-Pointing-Pointer We found ATM and DNA-PKcs function in a common pathway to suppress translocation. -- Abstract: It is well documented that deficiency in ataxia telangiectasia mutated (ATM) protein leads to elevated frequency of chromosome translocation, however, it remains poorly understood how ATM suppresses translocation frequency. In the present study, we addressed the mechanism of ATM-dependent suppression of translocation frequency. To know frequency of translocation events in a whole genome at once, we performed centromere/telomere FISH and scored dicentric chromosomes, because dicentric and translocation occur with equal frequency and by identical mechanism. By centromere/telomere FISH analysis, we confirmed that chemical inhibition or RNAi-mediated knockdown of ATM causes 2 to 2.5-fold increase in dicentric frequency at first mitosis after 2 Gy of gamma-irradiation in G0/G1. The FISH analysis revealed that ATM/p53-dependent G1 checkpoint suppresses dicentric frequency, since RNAi-mediated knockdown of p53 elevated dicentric frequency by 1.5-fold. We found ATM also suppresses dicentric occurrence independently of its checkpoint role, as ATM inhibitor showed additional effect on dicentric frequency in the context of p53 depletion and Chk1/2 inactivation. Epistasis analysis using chemical inhibitors revealed that ATM kinase functions in the same pathway that requires kinase activity of DNA-dependent protein kinase catalytic subunit (DNA-PKcs) to suppress dicentric frequency. From the results in the present study, we conclude that ATM minimizes translocation frequency through its commitment to G1 checkpoint and DNA double-strand break repair pathway that requires kinase activity of DNA-PKcs.

  19. Methods for suppressing isomerization of olefin metathesis products

    DOEpatents

    Firth, Bruce E.; Kirk, Sharon E.

    2015-10-27

    A method for suppressing isomerization of an olefin metathesis product produced in a metathesis reaction includes adding an isomerization suppression agent that includes nitric acid to a mixture that includes the olefin metathesis product and residual metathesis catalyst from the metathesis reaction under conditions that are sufficient to passivate at least a portion of the residual metathesis catalyst. Methods of refining a natural oil are described.

  20. Application of phase coherent transform to cloud clutter suppression

    SciTech Connect

    Ng, L.C.

    1994-11-15

    This paper describes a tracking algorithm using frame-to-frame correlation with frequency domain clutter suppression. Clutter suppression was mechanized via a `Phase Coherent Transform` (PCT) approach. This approach was applied to explore the feasibility of tracking a post-boost rocket from a low earth orbit satellite with real cloud background data. Simulation results show that the PCT/correlation tracking algorithm can perform satisfactorily at signal-to-clutter ratio (SCR) as low as 5 or 7 dB.

  1. [Suppression of epileptiform activity by micropolarizing brain structures].

    PubMed

    Tsukunov, S G; Gal'dinov, G V

    1980-05-01

    Penicillin administration elicited epileptiform responses whereas micropolarization (MCP) affected the epileptogenic foci in cats with indwelled electrodes and chemotrodes. Three types of experimental epilepsy models were obtained: focal petit mal seizures, adversive, and grand mal seizures. The MCP of amygdala and caudate nucleus completely suppressed all three types of seizures whereas MCP of hippocampus enhanced the pathology. Two mechanisms of seizure suppression seem to exist: the inhibitory and the activating ones.

  2. Expressive suppression and neural responsiveness to nonverbal affective cues

    PubMed Central

    Petrican, Raluca; Rosenbaum, R. Shayna; Grady, Cheryl

    2016-01-01

    Optimal social functioning occasionally requires concealment of one’s emotions in order to meet one’s immediate goals and environmental demands. However, because emotions serve an important communicative function, their habitual suppression disrupts the flow of social exchanges and, thus, incurs significant interpersonal costs. Evidence is accruing that the disruption in social interactions, linked to habitual expressive suppression use, stems not only from intrapersonal, but also from interpersonal causes, since the suppressors’ restricted affective displays reportedly inhibit their interlocutors’ emotionally expressive behaviors. However, expressive suppression use is not known to lead to clinically significant social impairments. One explanation may be that over the lifespan, individuals who habitually suppress their emotions come to compensate for their interlocutors’ restrained expressive behaviors by developing an increased sensitivity to nonverbal affective cues. To probe this issue, the present study used functional magnetic resonance imaging (fMRI) to scan healthy older women while they viewed silent videos of a male social target displaying nonverbal emotional behavior, together with a brief verbal description of the accompanying context, and then judged the target’s affect. As predicted, perceivers who reported greater habitual use of expressive suppression showed increased neural processing of nonverbal affective cues. This effect appeared to be coordinated in a top-down manner via cognitive control. Greater neural processing of nonverbal cues among perceivers who habitually suppress their emotions was linked to increased ventral striatum activity, suggestive of increased reward value/personal relevance ascribed to emotionally expressive nonverbal behaviors. These findings thus provide neural evidence broadly consistent with the hypothesized link between habitual use of expressive suppression and compensatory development of increased

  3. Social responses to expressive suppression: The role of personality judgments.

    PubMed

    Tackman, Allison M; Srivastava, Sanjay

    2016-04-01

    Why do people who suppress their emotion-expressive behavior have difficulty forming close, supportive relationships? Previous studies have found that suppression disrupts the dynamics of social interactions and existing relationships. We evaluated a complementary hypothesis: that suppression functions as a behavioral cue leading others to form negative personality impressions of suppressors, even at zero-acquaintance. In 2 studies, participants reported personality judgments and other impressions of targets who either suppressed or expressed their emotion-expressive behavior in response to amusing or sad film clips. In findings replicated across studies, targets who suppressed either amusement or sadness were judged as less extraverted, less agreeable, and more interpersonally avoidant and anxious than targets who expressed emotions, and participants were less interested in affiliating with suppressors compared with expressers. Effects were amplified when targets suppressed amusement (compared with sadness) and when participants knew the emotional context (compared with when they did not) and, thus, could form expectations about what emotions targets should be showing. Extraversion and agreeableness judgments mediated the effect of suppression on participants' disinterest in affiliating. In Study 2, which extended Study 1 in several ways, effects were pronounced for the enthusiasm aspect of extraversion and the compassion aspect of agreeableness. We also found evidence that judgments of suppressors do not simply fall between neutral and fully expressing targets; rather, judgments of suppressors are qualitatively different. We discuss implications for understanding the social consequences of emotion regulation-in particular, how beyond disrupting relationships, suppression may prevent some relationships from even forming in the first place.

  4. Failure of pyridoxine to suppress raised serum prolactin levels.

    PubMed

    de Waal, J M; Steyn, A F; Harms, J H; Slabber, C F; Pannall, P R

    1978-02-25

    Pyridoxine has been reported as having an antilactogenic effect, presumably by suppressing prolactin secretion. We have measured serum prolactin levels during pyridoxine administration in two groups of hyperprolactinaemic subjects. In normal postpartum women, the postdelivery fall in serum prolactin levels did not differ significantly in treated and control subjects. In patients with chlorpromazine-induced hyperprolactinaemia and galactorrhoea, pyridoxine did not reduce the elevated levels. In neither group was milk production suppressed.

  5. Suppression of antigen-specific lymphocyte activation in modeled microgravity

    NASA Technical Reports Server (NTRS)

    Cooper, D.; Pride, M. W.; Brown, E. L.; Risin, D.; Pellis, N. R.; McIntire, L. V. (Principal Investigator)

    2001-01-01

    Various parameters of immune suppression are observed in lymphocytes from astronauts during and after a space flight. It is difficult to ascribe this suppression to microgravity effects on immune cells in crew specimens, due to the complex physiological response to space flight and the resultant effect on in vitro immune performance. Use of isolated immune cells in true and modeled microgravity in immune performance tests, suggests a direct effect of microgravity on in vitro cellular function. Specifically, polyclonal activation of T-cells is severely suppressed in true and modeled microgravity. These recent findings suggest a potential suppression of oligoclonal antigen-specific lymphocyte activation in microgravity. We utilized rotating wall vessel (RWV) bioreactors as an analog of microgravity for cell cultures to analyze three models of antigen-specific activation. A mixed-lymphocyte reaction, as a model for a primary immune response, a tetanus toxoid response and a Borrelia burgdorferi response, as models of a secondary immune response, were all suppressed in the RWV bioreactor. Our findings confirm that the suppression of activation observed with polyclonal models also encompasses oligoclonal antigen-specific activation.

  6. Herbivore exploits orally secreted bacteria to suppress plant defenses

    PubMed Central

    Chung, Seung Ho; Rosa, Cristina; Scully, Erin D.; Peiffer, Michelle; Tooker, John F.; Hoover, Kelli; Luthe, Dawn S.; Felton, Gary W.

    2013-01-01

    Induced plant defenses in response to herbivore attack are modulated by cross-talk between jasmonic acid (JA)- and salicylic acid (SA)-signaling pathways. Oral secretions from some insect herbivores contain effectors that overcome these antiherbivore defenses. Herbivores possess diverse microbes in their digestive systems and these microbial symbionts can modify plant–insect interactions; however, the specific role of herbivore-associated microbes in manipulating plant defenses remains unclear. Here, we demonstrate that Colorado potato beetle (Leptinotarsa decemlineata) larvae exploit bacteria in their oral secretions to suppress antiherbivore defenses in tomato (Solanum lycopersicum). We found that antibiotic-untreated larvae decreased production of JA and JA-responsive antiherbivore defenses, but increased SA accumulation and SA-responsive gene expression. Beetles benefit from down-regulating plant defenses by exhibiting enhanced larval growth. In SA-deficient plants, suppression was not observed, indicating that suppression of JA-regulated defenses depends on the SA-signaling pathway. Applying bacteria isolated from larval oral secretions to wounded plants confirmed that three microbial symbionts belonging to the genera Stenotrophomonas, Pseudomonas, and Enterobacter are responsible for defense suppression. Additionally, reinoculation of these bacteria to antibiotic-treated larvae restored their ability to suppress defenses. Flagellin isolated from Pseudomonas sp. was associated with defense suppression. Our findings show that the herbivore exploits symbiotic bacteria as a decoy to deceive plants into incorrectly perceiving the threat as microbial. By interfering with the normal perception of herbivory, beetles can evade antiherbivore defenses of its host. PMID:24019469

  7. Suppression of antigen-specific lymphocyte activation in modeled microgravity.

    PubMed

    Cooper, D; Pride, M W; Brown, E L; Risin, D; Pellis, N R

    2001-02-01

    Various parameters of immune suppression are observed in lymphocytes from astronauts during and after a space flight. It is difficult to ascribe this suppression to microgravity effects on immune cells in crew specimens, due to the complex physiological response to space flight and the resultant effect on in vitro immune performance. Use of isolated immune cells in true and modeled microgravity in immune performance tests, suggests a direct effect of microgravity on in vitro cellular function. Specifically, polyclonal activation of T-cells is severely suppressed in true and modeled microgravity. These recent findings suggest a potential suppression of oligoclonal antigen-specific lymphocyte activation in microgravity. We utilized rotating wall vessel (RWV) bioreactors as an analog of microgravity for cell cultures to analyze three models of antigen-specific activation. A mixed-lymphocyte reaction, as a model for a primary immune response, a tetanus toxoid response and a Borrelia burgdorferi response, as models of a secondary immune response, were all suppressed in the RWV bioreactor. Our findings confirm that the suppression of activation observed with polyclonal models also encompasses oligoclonal antigen-specific activation.

  8. CMB quadrupole suppression. II. The early fast roll stage

    NASA Astrophysics Data System (ADS)

    Boyanovsky, D.; de Vega, H. J.; Sanchez, N. G.

    2006-12-01

    Within the effective field theory of inflation, an initialization of the classical dynamics of the inflaton with approximate equipartition between the kinetic and potential energy of the inflaton leads to a brief fast roll stage that precedes the slow roll regime. The fast roll stage leads to an attractive potential in the wave equations for the mode functions of curvature and tensor perturbations. The evolution of the inflationary perturbations is equivalent to the scattering by this potential and a useful dictionary between the scattering data and observables is established. Implementing methods from scattering theory we prove that this attractive potential leads to a suppression of the quadrupole moment for CMB and B-mode angular power spectra. The scale of the potential is determined by the Hubble parameter during slow roll. Within the effective field theory of inflation at the grand unification (GUT) energy scale we find that if inflation lasts a total number of e-folds Ntot˜59, there is a 10% 20% suppression of the CMB quadrupole and about 2% 4% suppression of the tensor quadrupole. The suppression of higher multipoles is smaller, falling off as 1/l2. The suppression is much smaller for Ntot>59, therefore if the observable suppression originates in the fast roll stage, there is the upper bound Ntot˜59.

  9. Knockdown of GALNT1 suppresses malignant phenotype of hepatocellular carcinoma by suppressing EGFR signaling

    PubMed Central

    Huang, Miao-Juei; Hu, Rey-Heng; Chou, Chih-Hsing; Hsu, Chia-Lang; Liu, Ya-Wen; Huang, John; Hung, Ji-Shiang; Lai, I-Rue; Juan, Hsueh-Fen; Yu, Sung-Liang; Wu, Yao-Ming; Huang, Min-Chuan

    2015-01-01

    O-glycosylation is a common protein modification. Aberrant O-glycosylation is associated with many cancers. GALNT1 is a GalNAc-transferase that initiates protein O-glycosylation. We found that GALNT1 is frequently up-regulated in hepatocellular carcinoma (HCC) and is associated with poor patient survival. Overexpression of GALNT1 increased and knockdown decreased HCC cell migration and invasion. Knockdown of GALNT1 inhibited EGF-induced migration and invasion. Knockdown of GALNT1 decreased EGFR activation and increased EGFR degradation, by decreasing EGFR O-glycosylation. This study demonstrates that down-regulation of GALNT1 is sufficient to suppress malignant phenotype of HCC cells by decreasing EGFR signaling. Thus, GALNT1 is a potential target in HCC. PMID:25730904

  10. Suppression of pool fires with HRC-125 in a simulated engine nacelle.

    SciTech Connect

    Keyser, David R.; Hewson, John C.

    2007-06-01

    CFD simulations are conducted to predict the distribution of fire suppressant in an engine nacelle and to predict the suppression of pool fires by the application of this suppressant. In the baseline configuration, which is based on an installed system, suppressant is injected through four nozzles at a rate fast enough to suppress all simulated pool fires. Variations that reduce the mass of the suppression system (reducing the impact of the suppression system on meeting mission needs) are considered, including a reduction in the rate of suppressant injection, a reduction in the mass of suppressant and a reduction in the number of nozzles. In general, these variations should work to reduce the effectiveness of the suppression system, but the CFD results point out certain changes that have negligible impact, at least for the range of phenomena considered here. The results are compared with measurements where available. Comparisons with suppressant measurements are reasonable. A series of twenty-three fire suppression tests were conducted to check the predictions. The pre-test predictions were generally successful in identifying the range of successful suppression tests. In two separate cases, each where one nozzle of the suppression system was capped, the simulation results did indicate a failure to suppress for a condition where the tests indicated successful suppression. When the test-suppressant discharge rate was reduced by roughly 25%, the tests were in agreement with the predictions. That is, the simulations predict a failure to suppress slightly before observed in these cases.

  11. Two Components of Nocturnal Locomotor Suppression by Light

    PubMed Central

    Morin, Lawrence P.; Lituma, Pablo J.; Studholme, Keith M.

    2010-01-01

    In nocturnal rodents, millisecond light (“flash”) stimuli can induce both a large circadian rhythm phase shift and an associated state change from highly active to quiescence followed by behavioral sleep. Suppression of locomotion (“negative masking”) is an easily measured correlate of the state change. The present mouse studies used both flashes and longer light stimuli (“pulses”) to distinguish initiation from maintenance effects of light on locomotor suppression and to determine whether the locomotor suppression exhibits temporal integration as is thought to be characteristic of phase shift responses to pulse, but not flash, stimuli. In Expt. 1, locomotor suppression increased with irradiance (0.01–100 μW/cm2), in accordance with previous reports. It also increased with stimulus duration (3–3000 sec), but interpretation of this result is complicated by the ability of light to both initiate and maintain locomotor suppression. In Expt. 2, an irradiance response curve was determined using a stimulus series of 10 flashes, 2 msec each, with total flash energy varying from 0.0025 – 110.0 J/m2. This included a test for temporal integration in which the effects of two equal energy series of flashes were compared, but which differed in the number of flashes per series (10 vs 100). The 10 flash series more effectively elicited locomotor suppression than the 100 flash series, a result consistent with prior observations involving flash-induced phase shifts. In Expt. 3, exposure of mice to an 11 hr light stimulus yielded irradiance-dependent locomotor suppression that can be maintained for the entire stimulus duration by a 100 μW/cm2 stimulus. Light has the ability to initiate a time-limited (30–40 min) interval of locomotor suppression (initiation effect) that can be extended by additional light (maintenance effect). Temporal integration resembling that seen in phase shifting responses to light does not exist for either phase shift or locomotor

  12. Persistence and Suppressiveness of Pasteuria penetrans to Meloidogyne arenaria Race

    PubMed Central

    Cetintas, R.; Dickson, D. W.

    2004-01-01

    The long-term persistence and suppressiveness of Pasteuria penetrans against Meloidogyne arenaria race 1 were investigated in a formerly root-knot nematode suppressive site following 9 years of continuous cultivation of three treatments and 4 years of continuous peanut. The three treatments were two M. arenaria race 1 nonhost crops, bahiagrass (Paspalum notatum cv. Pensacola var. Tifton 9), rhizomal peanut (Arachis glabrata cv. Florigraze), and weed fallow. Two root-knot nematode susceptible weeds commonly observed in weed fallow plots were hairy indigo (Indigofera hirsuta) and alyce clover (Alysicarpus vaginalis). The percentage of J2 with endospores attached reached the highest level of 87% in 2000 in weed fallow, and 63% and 53% in 2002 in bahiagrass and rhizomal peanut, respectively. The percentage of endospore-filled females extracted from peanut roots grown in weed fallow plots increased from nondetectable in 1999 to 56% in 2002, whereas the percentages in bahiagrass and rhizomal peanut plots were 41% and 16%, respectively. Over 4 years, however, there was no strong evidence that endospores densities reached suppressive levels because peanut roots, pods, and pegs were heavily galled, and yields were suppressed. This might be attributed to the discovery of M. javanica infecting peanut in this field in early autumn 2001. A laboratory test confirmed that although the P. penetrans isolate specific to M. arenaria attached to M. javanica J2, no development occurred. In summary, P. penetrans increased on M. arenaria over a 4-year period, but apparently because of infection of M. javanica on peanut at the field site root-knot disease was not suppressed. This was confirmed by a suppressive soil test that showed a higher level of soil suppressiveness than occurred in the field (P ≤ 0.01). PMID:19262836

  13. Persistence and Suppressiveness of Pasteuria penetrans to Meloidogyne arenaria Race.

    PubMed

    Cetintas, R; Dickson, D W

    2004-12-01

    The long-term persistence and suppressiveness of Pasteuria penetrans against Meloidogyne arenaria race 1 were investigated in a formerly root-knot nematode suppressive site following 9 years of continuous cultivation of three treatments and 4 years of continuous peanut. The three treatments were two M. arenaria race 1 nonhost crops, bahiagrass (Paspalum notatum cv. Pensacola var. Tifton 9), rhizomal peanut (Arachis glabrata cv. Florigraze), and weed fallow. Two root-knot nematode susceptible weeds commonly observed in weed fallow plots were hairy indigo (Indigofera hirsuta) and alyce clover (Alysicarpus vaginalis). The percentage of J2 with endospores attached reached the highest level of 87% in 2000 in weed fallow, and 63% and 53% in 2002 in bahiagrass and rhizomal peanut, respectively. The percentage of endospore-filled females extracted from peanut roots grown in weed fallow plots increased from nondetectable in 1999 to 56% in 2002, whereas the percentages in bahiagrass and rhizomal peanut plots were 41% and 16%, respectively. Over 4 years, however, there was no strong evidence that endospores densities reached suppressive levels because peanut roots, pods, and pegs were heavily galled, and yields were suppressed. This might be attributed to the discovery of M. javanica infecting peanut in this field in early autumn 2001. A laboratory test confirmed that although the P. penetrans isolate specific to M. arenaria attached to M. javanica J2, no development occurred. In summary, P. penetrans increased on M. arenaria over a 4-year period, but apparently because of infection of M. javanica on peanut at the field site root-knot disease was not suppressed. This was confirmed by a suppressive soil test that showed a higher level of soil suppressiveness than occurred in the field (P

  14. Suppression of proinflammatory cytokines in monocytes by a tetravalent guanylhydrazone

    PubMed Central

    1996-01-01

    An overproduction of proinflammatory cytokines by activated macrophages/monocytes mediates the injurious sequelae of inflammation, septic shock, tissue injury, and cachexia. We recently synthesized a tetravalent guanylhydrazone compound (CNI-1493) that inhibits cytokine- inducible arginine transport and nitric oxide (NO) production in macrophages, and protects mice against lethal endotoxemia and carrageenan-induced inflammation. During these investigations we noticed that CNI-1493 effectively prevented lipopolysaccharide (LPS)- induced NO production, even when added in concentrations 10-fold less than required to competitively inhibit L-arginine uptake, suggesting that the suppressive effects of this guanylhydrazone compound might extend to other LPS-induced responses. Here, we report that CNI-1493 suppressed the LPS-stimulated production of proinflammatory cytokines (tumor necrosis factor [TNF], interleukins 1beta and 6, macrophage inflammatory proteins 1alpha and 1beta) from human peripheral blood mononuclear cells. Cytokine suppression was specific, in that CNI-1493 did not inhibit either the constitutive synthesis of transforming growth factor beta or the upregulation of major histocompatibility complex class II by interferon gamma (IFN-gamma). In contrast to the macrophage suppressive actions of dexamethasone, which are overridden in the presence of IFN-gamma, CNI-1493 retained its suppressive effects even in the presence of IFN-gamma. The mechanism of cytokine- suppressive action by CNI-1493 was independent of extracellular L- arginine content and NO production and is not restricted to induction by LPS. As a selective inhibitor of macrophage activation that prevents TNF production, this tetravalent guanylhydrazone could be useful in the development of cytokine-suppressive agents for the treatment of diseases mediated by overproduction of cytokines. PMID:8642296

  15. Retinal Pigment Epithelial Cell Line Suppression of Phagolysosome Activation.

    PubMed

    Taylor, A W; Dixit, S; Yu, J

    2015-01-29

    The eye is an immune privileged tissue with multiple mechanisms of immunosuppression to protect the light gathering tissues from the damage of inflammation. One of theses mechanisms involves retinal pigment epithelial cell suppression of phagosome activation in macrophages. The objective of this work is to determine if the human RPE cell line ARPE-19 is capable of suppressing the activation of the phagolysosome in macrophages in a manner similar to primary RPE. The conditioned media of RPE eyecups, sub-confluent, just confluent cultures, or established confluent cultures of human ARPE-19 cells were generated. These condition media were used to treat macrophages phagocytizing pHrodo bioparticles. After 24 hours incubation the macrophages were imaged by fluorescent microscopy, and fluorescence was measured. The fluorescent intensity is proportional to the amount of bioparticles phagocytized and are in an activated phagolysosome. The conditioned media of in situ mouse RPE eyecups significantly suppressed the activation of phagolysosome. The conditioned media from cultures of human ARPE-19 cells, grown to sub-confluence (50%) or grown to confluence had no effect on phagolysosome activation. In contrast, the conditioned media from established confluent cultures significantly suppressed phagolysosome activation. The neuropeptides alpha-MSH and NPY were depleted from the conditioned media of established confluent ARPE-19 cell cultures. This depleted conditioned media had diminished suppression of phagolysosome activation while promoting macrophage cell death. In addition, the condition media from cultures of ARPE-19 monolayers wounded with a bisecting scrape was diminished in suppressing phagolysosome activation. This technical report suggests that like primary RPE monolayers, established confluent cultures of ARPE-19 cells produce soluble factors that suppress the activation of macrophages, and can be used to study the molecular mechanisms of retinal immunobiology. In

  16. Diversity and Activity of Lysobacter Species from Disease Suppressive Soils

    PubMed Central

    Gómez Expósito, Ruth; Postma, Joeke; Raaijmakers, Jos M.; De Bruijn, Irene

    2015-01-01

    The genus Lysobacter includes several species that produce a range of extracellular enzymes and other metabolites with activity against bacteria, fungi, oomycetes, and nematodes. Lysobacter species were found to be more abundant in soil suppressive against the fungal root pathogen Rhizoctonia solani, but their actual role in disease suppression is still unclear. Here, the antifungal and plant growth-promoting activities of 18 Lysobacter strains, including 11 strains from Rhizoctonia-suppressive soils, were studied both in vitro and in vivo. Based on 16S rRNA sequencing, the Lysobacter strains from the Rhizoctonia-suppressive soil belonged to the four species Lysobacter antibioticus, Lysobacter capsici, Lysobacter enzymogenes, and Lysobacter gummosus. Most strains showed strong in vitro activity against R. solani and several other pathogens, including Pythium ultimum, Aspergillus niger, Fusarium oxysporum, and Xanthomonas campestris. When the Lysobacter strains were introduced into soil, however, no significant and consistent suppression of R. solani damping-off disease of sugar beet and cauliflower was observed. Subsequent bioassays further revealed that none of the Lysobacter strains was able to promote growth of sugar beet, cauliflower, onion, and Arabidopsis thaliana, either directly or via volatile compounds. The lack of in vivo activity is most likely attributed to poor colonization of the rhizosphere by the introduced Lysobacter strains. In conclusion, our results demonstrated that Lysobacter species have strong antagonistic activities against a range of pathogens, making them an important source for putative new enzymes and antimicrobial compounds. However, their potential role in R. solani disease suppressive soil could not be confirmed. In-depth omics'–based analyses will be needed to shed more light on the potential contribution of Lysobacter species to the collective activities of microbial consortia in disease suppressive soils. PMID:26635735

  17. A simplified model of decontamination by BWR steam suppression pools

    SciTech Connect

    Powers, D.A.

    1997-05-01

    Phenomena that can decontaminate aerosol-laden gases sparging through steam suppression pools of boiling water reactors during reactor accidents are described. Uncertainties in aerosol properties, aerosol behavior within gas bubbles, and bubble behavior in plumes affect predictions of decontamination by steam suppression pools. Uncertainties in the boundary and initial conditions that are dictated by the progression of severe reactor accidents and that will affect predictions of decontamination by steam suppression pools are discussed. Ten parameters that characterize boundary and initial condition uncertainties, nine parameters that characterize aerosol property and behavior uncertainties, and eleven parameters that characterize uncertainties in the behavior of bubbles in steam suppression pools are identified. Ranges for the values of these parameters and subjective probability distributions for parametric values within the ranges are defined. These uncertain parameters are used in Monte Carlo uncertainty analyses to develop uncertainty distributions for the decontamination that can be achieved by steam suppression pools and the size distribution of aerosols that do emerge from such pools. A simplified model of decontamination by steam suppression pools is developed by correlating features of the uncertainty distributions for total decontamination factor, DF(total), mean size of emerging aerosol particles, d{sub p}, and the standard deviation of the emerging aerosol size distribution, {sigma}, with pool depth, H. Correlations of the median values of the uncertainty distributions are suggested as the best estimate of decontamination by suppression pools. Correlations of the 10 percentile and 90 percentile values of the uncertainty distributions characterize the uncertainty in the best estimates. 295 refs., 121 figs., 113 tabs.

  18. Tinnitus suppression by electric stimulation of the auditory nerve

    PubMed Central

    Chang, Janice E.; Zeng, Fan-Gang

    2012-01-01

    Electric stimulation of the auditory nerve via a cochlear implant (CI) has been observed to suppress tinnitus, but parameters of an effective electric stimulus remain unexplored. Here we used CI research processors to systematically vary pulse rate, electrode place, and current amplitude of electric stimuli, and measure their effects on tinnitus loudness and stimulus loudness as a function of stimulus duration. Thirteen tinnitus subjects who used CIs were tested, with nine (70%) being “Responders” who achieved greater than 30% tinnitus loudness reduction in response to at least one stimulation condition and the remaining four (30%) being “Non-Responders” who had less than 30% tinnitus loudness reduction in response to any stimulus condition tested. Despite large individual variability, several interesting observations were made between stimulation parameters, tinnitus characteristics, and tinnitus suppression. If a subject's tinnitus was suppressed by one stimulus, then it was more likely to be suppressed by another stimulus. If the tinnitus contained a “pulsating” component, then it would be more likely suppressed by a given combination of stimulus parameters than tinnitus without these components. There was also a disassociation between the subjects' clinical speech processor and our research processor in terms of their effectiveness in tinnitus suppression. Finally, an interesting dichotomy was observed between loudness adaptation to electric stimuli and their effects on tinnitus loudness, with the Responders exhibiting higher degrees of loudness adaptation than the Non-Responders. Although the mechanisms underlying these observations remain to be resolved, their clinical implications are clear. When using a CI to manage tinnitus, the clinical processor that is optimized for speech perception needs to be customized for optimal tinnitus suppression. PMID:22479238

  19. Arsenite suppression of BMP signaling in human keratinocytes

    SciTech Connect

    Phillips, Marjorie A.; Qin, Qin; Hu, Qin; Zhao, Bin; Rice, Robert H.

    2013-06-15

    Arsenic, a human skin carcinogen, suppresses differentiation of cultured keratinocytes. Exploring the mechanism of this suppression revealed that BMP-6 greatly increased levels of mRNA for keratins 1 and 10, two of the earliest differentiation markers expressed, a process prevented by co-treatment with arsenite. BMP also stimulated, and arsenite suppressed, mRNA for FOXN1, an important transcription factor driving early keratinocyte differentiation. Keratin mRNAs increased slowly after BMP-6 addition, suggesting they are indirect transcriptional targets. Inhibition of Notch1 activation blocked BMP induction of keratins 1 and 10, while FOXN1 induction was largely unaffected. Supporting a requirement for Notch1 signaling in keratin induction, BMP increased levels of activated Notch1, which was blocked by arsenite. BMP also greatly decreased active ERK, while co-treatment with arsenite maintained active ERK. Inhibition of ERK signaling mimicked BMP by inducing keratin and FOXN1 mRNAs and by increasing active Notch1, effects blocked by arsenite. Of 6 dual-specificity phosphatases (DUSPs) targeting ERK, two were induced by BMP unless prevented by simultaneous exposure to arsenite and EGF. Knockdown of DUSP2 or DUSP14 using shRNAs greatly reduced FOXN1 and keratins 1 and 10 mRNA levels and their induction by BMP. Knockdown also decreased activated Notch1, keratin 1 and keratin 10 protein levels, both in the presence and absence of BMP. Thus, one of the earliest effects of BMP is induction of DUSPs, which increases FOXN1 transcription factor and activates Notch1, both required for keratin gene expression. Arsenite prevents this cascade by maintaining ERK signaling, at least in part by suppressing DUSP expression. - Highlights: • BMP induces FOXN1 transcription. • BMP induces DUSP2 and DUSP14, suppressing ERK activation. • Arsenite suppresses levels of phosphorylated Smad1/5 and FOXN1 and DUSP mRNA. • These actions rationalize arsenite suppression of keratinocyte

  20. Detection of Burst Suppression Patterns in EEG Using Recurrence Rate

    PubMed Central

    Ren, Yongshao; Sleigh, Jamie; Li, Xiaoli

    2014-01-01

    Burst suppression is a unique electroencephalogram (EEG) pattern commonly seen in cases of severely reduced brain activity such as overdose of general anesthesia. It is important to detect burst suppression reliably during the administration of anesthetic or sedative agents, especially for cerebral-protective treatments in various neurosurgical diseases. This study investigates recurrent plot (RP) analysis for the detection of the burst suppression pattern (BSP) in EEG. The RP analysis is applied to EEG data containing BSPs collected from 14 patients. Firstly we obtain the best selection of parameters for RP analysis. Then, the recurrence rate (RR), determinism (DET), and entropy (ENTR) are calculated. Then RR was selected as the best BSP index one-way analysis of variance (ANOVA) and multiple comparison tests. Finally, the performance of RR analysis is compared with spectral analysis, bispectral analysis, approximate entropy, and the nonlinear energy operator (NLEO). ANOVA and multiple comparison tests showed that the RR could detect BSP and that it was superior to other measures with the highest sensitivity of suppression detection (96.49%, P = 0.03). Tracking BSP patterns is essential for clinical monitoring in critically ill and anesthetized patients. The purposed RR may provide an effective burst suppression detector for developing new patient monitoring systems. PMID:24883378

  1. Large scale power suppression in a multifield landscape

    SciTech Connect

    Blanco-Pillado, Jose J.; Frazer, Jonathan; Sousa, Kepa

    2015-08-01

    Power suppression of the cosmic microwave background on the largest observable scales could provide valuable clues about the particle physics underlying inflation. Here we consider the prospect of power suppression in the context of the multifield landscape. Based on the assumption that our observable universe emerges from a tunnelling event and that the relevant features originate purely from inflationary dynamics, we find that the power spectrum not only contains information on single-field dynamics, but also places strong constraints on all scalar fields present in the theory. We find that the simplest single-field models giving rise to power suppression do not generalise to multifield models in a straightforward way, as the resulting superhorizon evolution of the curvature perturbation tends to erase any power suppression present at horizon crossing. On the other hand, multifield effects do present a means of generating power suppression which to our knowledge has so far not been considered. We propose a mechanism to illustrate this, which we dub flume inflation.

  2. Leptin Suppresses Mouse Taste Cell Responses to Sweet Compounds.

    PubMed

    Yoshida, Ryusuke; Noguchi, Kenshi; Shigemura, Noriatsu; Jyotaki, Masafumi; Takahashi, Ichiro; Margolskee, Robert F; Ninomiya, Yuzo

    2015-11-01

    Leptin is known to selectively suppress neural and behavioral responses to sweet-tasting compounds. However, the molecular basis for the effect of leptin on sweet taste is not known. Here, we report that leptin suppresses sweet taste via leptin receptors (Ob-Rb) and KATP channels expressed selectively in sweet-sensitive taste cells. Ob-Rb was more often expressed in taste cells that expressed T1R3 (a sweet receptor component) than in those that expressed glutamate-aspartate transporter (a marker for Type I taste cells) or GAD67 (a marker for Type III taste cells). Systemically administered leptin suppressed taste cell responses to sweet but not to bitter or sour compounds. This effect was blocked by a leptin antagonist and was absent in leptin receptor-deficient db/db mice and mice with diet-induced obesity. Blocking the KATP channel subunit sulfonylurea receptor 1, which was frequently coexpressed with Ob-Rb in T1R3-expressing taste cells, eliminated the effect of leptin on sweet taste. In contrast, activating the KATP channel with diazoxide mimicked the sweet-suppressing effect of leptin. These results indicate that leptin acts via Ob-Rb and KATP channels that are present in T1R3-expressing taste cells to selectively suppress their responses to sweet compounds.

  3. Attention selection, distractor suppression and N2pc.

    PubMed

    Mazza, Veronica; Turatto, Massimo; Caramazza, Alfonso

    2009-01-01

    N2pc is generally interpreted as the electrocortical correlate of the distractor-suppression mechanisms through which attention selection takes place in humans. Here, we present data that challenge this common N2pc interpretation. In Experiment 1, multiple distractors induced greater N2pc amplitudes even when they facilitated target identification, despite the suppression account of the N2pc predicted the contrary; in Experiment 2, spatial proximity between target and distractors did not affect the N2pc amplitude, despite resulting in more interference in response times; in Experiment 3, heterogeneous distractors delayed response times but did not elicit a greater N2pc relative to homogeneous distractors again in contrast with what would have predicted the suppression hypothesis. These results do not support the notion that the N2pc unequivocally mirrors distractor-suppression processes. We propose that the N2pc indexes mechanisms involved in identifying and localizing relevant stimuli in the scene through enhancement of their features and not suppression of distractors.

  4. Bitter gourd suppresses lipopolysaccharide-induced inflammatory responses.

    PubMed

    Kobori, Masuko; Nakayama, Hirosuke; Fukushima, Kenji; Ohnishi-Kameyama, Mayumi; Ono, Hiroshi; Fukushima, Tatsunobu; Akimoto, Yukari; Masumoto, Saeko; Yukizaki, Chizuko; Hoshi, Yoshikazu; Deguchi, Tomoaki; Yoshida, Mitsuru

    2008-06-11

    Bitter gourd ( Momordica charantia L.) is a popular tropical vegetable in Asian countries. Previously it was shown that bitter gourd placenta extract suppressed lipopolysaccharide (LPS)-induced TNFalpha production in RAW 264.7 macrophage-like cells. Here it is shown that the butanol-soluble fraction of bitter gourd placenta extract strongly suppresses LPS-induced TNFalpha production in RAW 264.7 cells. Gene expression analysis using a fibrous DNA microarray showed that the bitter gourd butanol fraction suppressed expression of various LPS-induced inflammatory genes, such as those for TNF, IL1alpha, IL1beta, G1p2, and Ccl5. The butanol fraction significantly suppressed NFkappaB DNA binding activity and phosphorylation of p38, JNK, and ERK MAPKs. Components in the active fraction from bitter gourd were identified as 1-alpha-linolenoyl-lysophosphatidylcholine (LPC), 2-alpha-linolenoyl-LPC, 1-lynoleoyl-LPC, and 2-linoleoyl-LPC. Purified 1-alpha-linolenoyl-LPC and 1-linoleoyl-LPC suppressed the LPS-induced TNFalpha production of RAW 264.7 cells at a concentration of 10 microg/mL.

  5. Potent cough suppression by physiologically active substance in human plasma.

    PubMed

    Akaike, Norio; Ito, Yushi; Ogawa, Sachie K; Maeda, Megumi; Wakita, Masahito; Takahama, Kazuo; Noguchi, Tetsuro; Kamei, Shintaro; Hamamoto, Takayoshi; Umehashi, Misako; Maeda, Hiroaki

    2014-01-01

    Human plasma contains wide variety of bioactive proteins that have proved essential in therapeutic discovery. However many human plasma proteins remain orphans with unknown biological functions. Evidences suggest that some plasma components target the respiratory system. In the present study we adapted heparin affinity chromatography to fractionate human plasma for functional bioassay. Fractions from pooled human plasma yielded particular plasma fractions with strong cough suppressing effects. Purification yielded a fraction that was finally identified as an activated blood coagulation factor fXIa using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and matrix-assisted laser desorption ionization/time-of-flight mass spectrometry (MALDI/TOF-MS). The fraction almost completely suppressed coughs induced by either chemical or mechanical stimulation applied to larynx or bifurcation of guinea-pig trachea. Cough suppressing effect of the fraction and commercially available fXIa were one million times stronger than codeine and codeine only partially suppressed the mechanically triggered coughing in animal model. Recent reviews highlighted prominent shortcomings of current available antitussives, including narcotic opioids such as codeine and their unpleasant or intolerable side effects. Therefore, safer and more effective cough suppressants would be welcome, and present findings indicate that fXIa in human plasma as a very promising, new therapeutic candidate for effective antitussive action.

  6. Shikonin Suppresses Skin Carcinogenesis via Inhibiting Cell Proliferation.

    PubMed

    Li, Wenjuan; Zhang, Chunjing; Ren, Amy; Li, Teena; Jin, Rong; Li, Guohong; Gu, Xin; Shi, Runhua; Zhao, Yunfeng

    2015-01-01

    The M2 isoform of pyruvate kinase M2 (PKM2) has been shown to be up-regulated in human skin cancers. To test whether PKM2 may be a target for chemoprevention, shikonin, a natural product from the root of Lithospermum erythrorhizon and a specific inhibitor of PKM2, was used in a chemically-induced mouse skin carcinogenesis study. The results revealed that shikonin treatment suppressed skin tumor formation. Morphological examinations and immunohistochemical staining of the skin epidermal tissues suggested that shikonin inhibited cell proliferation without inducing apoptosis. Although shikonin alone suppressed PKM2 activity, it did not suppress tumor promoter-induced PKM2 activation in the skin epidermal tissues at the end of the skin carcinogenesis study. To reveal the potential chemopreventive mechanism of shikonin, an antibody microarray analysis was performed, and the results showed that the transcription factor ATF2 and its downstream target Cdk4 were up-regulated by chemical carcinogen treatment; whereas these up-regulations were suppressed by shikonin. In a promotable skin cell model, the nuclear levels of ATF2 were increased during tumor promotion, whereas this increase was inhibited by shikonin. Furthermore, knockdown of ATF2 decreased the expression levels of Cdk4 and Fra-1 (a key subunit of the activator protein 1. In summary, these results suggest that shikonin, rather than inhibiting PKM2 in vivo, suppresses the ATF2 pathway in skin carcinogenesis.

  7. Effect of burst parameters on automotive brake squeal suppression

    NASA Astrophysics Data System (ADS)

    Badertscher, Jeff; Cunefare, Kenneth A.

    2003-04-01

    Implementing a dither control signal with a 100% duty cycle is an effective means of suppressing automotive brake squeal. Dither control is a method by which high-frequency control efforts are introduced into a system to suppress a lower frequency disturbance. Dither is introduced to a brake by placing a piezoelectric stack actuator in the piston of a floating caliper brake. Burst mode dither control is characterized by duty cycles of less than 100%. A burst control signal of a specific duty cycle is also specified by the burst count and burst rate. Burst mode signals are shown to suppress brake squeal. This paper examines the nature of suppression and the effectiveness of burst mode dither control signals with varied burst parameters. An examination of the squeal response and dither control signal is used to examine the nature of suppression during bursting and dwell time. The amplitude of the control signal that is necessary to obtain full control of the system is used to assess control signal effectiveness.

  8. Prevention of cancer by agents that suppress oxygen radical formation.

    PubMed

    Troll, W

    1991-01-01

    The prevention of cancer by agents in our diet has led to the concept that oxygen radicals are a necessary component of a variety of human cancers including breast, colon and prostatic cancer. These cancers are putatively promoted by estradiol, bile acids and androgens. Epidemiological studies have shown that these cancers are suppressed in vegetarian populations. Vegetable components that may be responsible for this cancer prevention are Vitamin A, retinoids and protease inhibitors (PIs). These agents have been shown to suppress the formation of hydrogen peroxide in promoter-induced neutrophils. They also have been shown to block two-stage carcinogenesis and breast cancer when fed to animals. PIs also suppress experimentally-induced colon cancer and spontaneous liver cancer. Moreover, a new series of cancer-preventive agents, Sarcophytols (isolated by Fujiki and co-workers), are capable of suppressing two-stage carcinogenesis, breast and colon cancers in rodents when given in low concentrations. Sarcophytols were also active suppressors of H2O2 formation of 12-O-tetradecanoyl-phorbol-13-acetate (TPA)-induced neutrophils. These observations point to an essential role of oxygen radicals in carcinogenesis. Suppression of the oxygen radical response of neutrophils in relation to cancer preventive agents is a facile assay of these important substances. The mechanism of action of oxygen radicals in promoting carcinogenesis is a multiple one, including: (1) activation of oncogenes, (2) modification of DNA bases, and (3) formation of single-strand breaks leading to poly(ADP)ribose polymerase activation.

  9. Reversible Smad-dependent signaling between tumor suppression and oncogenesis.

    PubMed

    Sekimoto, Go; Matsuzaki, Koichi; Yoshida, Katsunori; Mori, Shigeo; Murata, Miki; Seki, Toshihito; Matsui, Hirofumi; Fujisawa, Jun-ichi; Okazaki, Kazuichi

    2007-06-01

    Cancer cells often gain advantage by reducing the tumor-suppressive activity of transforming growth factor-beta (TGF-beta) together with stimulation of its oncogenic activity as in Ras-transformed cells; however, molecular mechanisms remain largely unknown. TGF-beta activates both its type I receptor (TbetaRI) and c-Jun NH2-terminal kinase (JNK), which phosphorylate Smad2 and Smad3 at the COOH-terminal (pSmad2/3C) and linker regions (pSmad2/3L). Here, we report that Ras transformation suppresses TbetaRI-mediated pSmad3C signaling, which involves growth inhibition by down-regulating c-Myc. Instead, hyperactive Ras constitutively stimulates JNK-mediated pSmad2/3L signaling, which fosters tumor invasion by up-regulating plasminogen activator inhibitor-1 and matrix metalloproteinase-1 (MMP-1), MMP-2, and MMP-9. Conversely, selective blockade of linker phosphorylation by a mutant Smad3 lacking JNK-dependent phosphorylation sites results in preserved tumor-suppressive function via pSmad3C in Ras-transformed cells while eliminating pSmad2/3L-mediated invasive capacity. Thus, specific inhibition of the JNK/pSmad2/3L pathway should suppress cancer progression by shifting Smad-dependent signaling from oncogenesis to tumor suppression.

  10. Recent results about fan noise: Its generation, radiation and suppression

    NASA Technical Reports Server (NTRS)

    Feiler, C. E.

    1982-01-01

    Fan noise including its generation, radiation characteristics, and suppression by acoustic treatment is studied. In fan noise generation, results from engine and fan experiments, using inflow control measures to suppress noise sources related to inflow distortion and turbulence, are described. The suppression of sources related to inflow allows the experiments to focus on the fan or engine internal sources. Some of the experiments incorporated pressure sensors on the fan blades to sample the flow disturbances encountered by the blades. From these data some inferences can be drawn about the origins of the disturbances. Also, hot wire measurements of a fan rotor wake field are presented and related to the fan's noise signature. The radiation and the suppression of fan noise are dependent on the acoustic modes generated by the fan. Fan noise suppression and radiation is described by relating these phenomena to the mode cutoff ratio parameter. In addition to its utility in acoustic treatment design and performance prediction, cutoff ratio was useful in developing a simple description of the radiation pattern for broadband fan noise. Some of the findings using the cutoff ratio parameter are presented.

  11. Leptin Suppresses Mouse Taste Cell Responses to Sweet Compounds

    PubMed Central

    Noguchi, Kenshi; Shigemura, Noriatsu; Jyotaki, Masafumi; Takahashi, Ichiro; Margolskee, Robert F.

    2015-01-01

    Leptin is known to selectively suppress neural and behavioral responses to sweet-tasting compounds. However, the molecular basis for the effect of leptin on sweet taste is not known. Here, we report that leptin suppresses sweet taste via leptin receptors (Ob-Rb) and KATP channels expressed selectively in sweet-sensitive taste cells. Ob-Rb was more often expressed in taste cells that expressed T1R3 (a sweet receptor component) than in those that expressed glutamate-aspartate transporter (a marker for Type I taste cells) or GAD67 (a marker for Type III taste cells). Systemically administered leptin suppressed taste cell responses to sweet but not to bitter or sour compounds. This effect was blocked by a leptin antagonist and was absent in leptin receptor–deficient db/db mice and mice with diet-induced obesity. Blocking the KATP channel subunit sulfonylurea receptor 1, which was frequently coexpressed with Ob-Rb in T1R3-expressing taste cells, eliminated the effect of leptin on sweet taste. In contrast, activating the KATP channel with diazoxide mimicked the sweet-suppressing effect of leptin. These results indicate that leptin acts via Ob-Rb and KATP channels that are present in T1R3-expressing taste cells to selectively suppress their responses to sweet compounds. PMID:26116698

  12. Organic and Inorganic Nitrogen Amendments to Soil as Nematode Suppressants

    PubMed Central

    Rodríguez-Kábana, R.

    1986-01-01

    Inorganic fertilizers containing ammoniacal nitrogen or formulations releasing this form of N in the soil are most effective for suppressing nematode populations. Anhydrous ammonia has been shown to reduce soil populations of Tylenchorhynchus claytoni, Helicotylenchus dihystera, and Heterodera glycines. The rates required to obtain significant suppression of nematode populations are generally in excess of 150 kg N/ha. Urea also suppresses several nematode species, including Meloidogyne spp., when applied at rates above 300 kg N/ha. Additional available carbon must be provided with urea to permit soil microorganisms to metabolize excess N and avoid phytotoxic effects. There is a direct relation between the amount of "protein" N in organic amendments and their effectiveness as nematode population suppressants. Most nematicidal amendments are oil cakes, or animal excrements containing 2-7% (w:w) N; these materials are effective at rates of 4-10 t/ha. Organic soil amendments containing mucopolysaccharides (e.g., mycelial wastes, chitinous matter) are also effective nematode suppressants. PMID:19294153

  13. Alpinetin targets glioma stem cells by suppressing Notch pathway.

    PubMed

    Wang, Jianpeng; Yan, Zhiyong; Liu, Xia; Che, Shusheng; Wang, Chao; Yao, Weicheng

    2016-07-01

    Glioma is among the most common human malignancies with poor prognosis. Glioma stem cells (GSCs) are the culprit of glioma, suggesting that GSCs are potential therapeutic targets. Notch signaling pathway plays a pivotal role for the function of GSCs, implying that suppression of Notch pathway may be an effective strategy for GSC-targeting therapy. In this study, we found that alpinetin, a natural compound, can suppress the proliferation and invasiveness of GSCs and induce apoptosis in GSCs. Immunoblot analysis and luciferase assay revealed that Notch signaling was suppressed by alpinetin. Furthermore, restoration of Notch signaling activity rescued the effect of alpinetin on GSC's function. The anti-tumor activity of alpinetin was further confirmed in an animal model. Collectively, targeting of GSC by alpinetin is an effective strategy for glioma therapy.

  14. Vibration suppression of composite laminated plate with nonlinear energy sink

    NASA Astrophysics Data System (ADS)

    Zhang, Ye-Wei; Zhang, Hao; Hou, Shuai; Xu, Ke-Fan; Chen, Li-Qun

    2016-06-01

    The composite laminated plate is widely used in supersonic aircraft. So, there are many researches about the vibration suppression of composite laminated plate. In this paper, nonlinear energy sink (NES) as an effective method to suppress vibration is studied. The coupled partial differential governing equations of the composite laminated plate with the nonlinear energy sink (NES) are established by using the Hamilton principle. The fourth-order Galerkin discrete method is used to truncate the partial differential equations, which are solved by numerical integration method. Meanwhile study about the precise effectiveness of the nonlinear energy sink (NES) by discussing the different installation location of the nonlinear energy sink (NES) at the same speed. The results indicate that the nonlinear energy sink (NES) can significantly suppress the severe vibration of the composite laminated plate with speed wind loadings in to protect the composite laminated plate from excessive vibration.

  15. Deconstructing p53 transcriptional networks in tumor suppression.

    PubMed

    Bieging, Kathryn T; Attardi, Laura D

    2012-02-01

    p53 is a pivotal tumor suppressor that induces apoptosis, cell-cycle arrest and senescence in response to stress signals. Although p53 transcriptional activation is important for these responses, the mechanisms underlying tumor suppression have been elusive. To date, no single or compound mouse knockout of specific p53 target genes has recapitulated the dramatic tumor predisposition that characterizes p53-null mice. Recently, however, analysis of knock-in mice expressing p53 transactivation domain mutants has revealed a group of primarily novel direct p53 target genes that may mediate tumor suppression in vivo. We present here an overview of well-known p53 target genes and the tumor phenotypes of the cognate knockout mice, and address the recent identification of new p53 transcriptional targets and how they enhance our understanding of p53 transcriptional networks central for tumor suppression.

  16. Experience with IBS-suppression lattice in RHIC

    SciTech Connect

    Litvinenko,V.N.; Luo, Y.; Ptitsyn, V.; Satogata, T.; Tepikian, S.; Bai, M.; Bruno, D.; Cameron, P.; Connolly, R.; Della Penna, A.; Drees, A.; Fedotov, A.; Ganetis, G.; Hoff, L.; Louie, W.; Malitsky, N.; Marr, G.; Marusic, A.; Montag, C.; Pilat, F.; Roser, T.; Trbojevic, D.; Tsoupas, N.

    2008-06-23

    An intra-beam scattering (IBS) is the limiting factor of the luminosity lifetime for RHIC operating with heavy ions. In order to suppress the IBS we designed and implemented new lattice with higher betatron tunes. This lattice had been developed during last three years and had been used for gold ions in yellow ring of the RHIC during d-Au part of the RHIC Run-8. The use of this lattice allowed both significant increases in the luminosity lifetime and the luminosity levels via reduction of beta-stars in the IPS. In this paper we report on the development, the tests and the performance of IBS-suppression lattice in RHIC, including the resulting increases in the peak and the average luminosity. We also report on our plans for future steps with the IBS suppression.

  17. Active and passive vibration suppression for space structures

    NASA Technical Reports Server (NTRS)

    Hyland, David C.

    1991-01-01

    The relative benefits of passive and active vibration suppression for large space structures (LSS) are discussed. The intent is to sketch the true ranges of applicability of these approaches using previously published technical results. It was found that the distinction between active and passive vibration suppression approaches is not as sharp as might be thought at first. The relative simplicity, reliability, and cost effectiveness touted for passive measures are vitiated by 'hidden costs' bound up with detailed engineering implementation issues and inherent performance limitations. At the same time, reliability and robustness issues are often cited against active control. It is argued that a continuum of vibration suppression measures offering mutually supporting capabilities is needed. The challenge is to properly orchestrate a spectrum of methods to reap the synergistic benefits of combined advanced materials, passive damping, and active control.

  18. Special regulatory T cell review: The suppression problem!

    PubMed

    Waldmann, Herman

    2008-01-01

    The concept of T-cell mediated suppression evolved more than 30 years ago. At that time it spawned many claims that have not stood the test of time. The rediscovery of suppression phenomena and regulatory T cells over the past 15 years created schizophrenic responses amongst immunologists. Some claimed that the new proponents of suppression were, once again, bringing immunology into disrepute, whilst others have embraced the field with great enthusiasm and novel approaches to clarification. Without faithful repetition of the "old" experiments, it is difficult to establish what was right and what was wrong. Nevertheless, immunologists must now accept that a good number of the old claims were overstated, and reflected poor scientific discipline. "I speak not to disprove what Brutus spoke, But here I am to speak what I do know" Shakespeare. Julius Caesar Act 3, Scene 2.

  19. A model for explaining fusion suppression using classical trajectory method

    NASA Astrophysics Data System (ADS)

    Phookan, C. K.; Kalita, K.

    2015-01-01

    We adopt a semi-classical approach for explanation of projectile breakup and above barrier fusion suppression for the reactions 6Li+152Sm and 6Li+144Sm. The cut-off impact parameter for fusion is determined by employing quantum mechanical ideas. Within this cut-off impact parameter for fusion, the fraction of projectiles undergoing breakup is determined using the method of classical trajectory in two-dimensions. For obtaining the initial conditions of the equations of motion, a simplified model of the 6Li nucleus has been proposed. We introduce a simple formula for explanation of fusion suppression. We find excellent agreement between the experimental and calculated fusion cross section. A slight modification of the above formula for fusion suppression is also proposed for a three-dimensional model.

  20. Line defect induced conductance suppression in graphene nanojunction

    NASA Astrophysics Data System (ADS)

    Li, Haidong; Li, Ruixue; Yu, Qiongyan; Kang, Xiubao; Ding, Jun

    2016-05-01

    Line defect induced conductance suppression in graphene nanojunction is investigated by means of Landauer-Bütikker formula and the nonequilibrium Green's function technique. With the increase of the longitudinal size of the device region, the conductance value decreases and tends to form two conductance valleys. Then we prove that the line defect can lead to localize states in the device region, which contributes to conductance valley at the point far away from Dirac point. And the zero conductance at the Dirac point is associated with the edge state localized at the zigzag-edged shoulder of the nanojunctions. The staggered potential can change energy spectrum structure of the device region, and produce strong conductance suppression. The line defect can efficiently enhance the conductance suppression, which can be utilized to realize the electron transport manipulation.

  1. Functional imaging correlates of impaired distractor suppression following sleep deprivation.

    PubMed

    Kong, Danyang; Soon, Chun Siong; Chee, Michael W L

    2012-05-15

    Sleep deprivation (SD) has been shown to affect selective attention but it is not known how two of its component processes: target enhancement and distractor suppression, are affected. To investigate, young volunteers either attended to houses or were obliged to ignore them (when attending to faces) while viewing superimposed face-house pictures. MR signal enhancement and suppression in the parahippocampal place area (PPA) were determined relative to a passive viewing control condition. Sleep deprivation was associated with lower PPA activation across conditions. Critically SD specifically impaired distractor suppression in selective attention, leaving target enhancement relatively preserved. These findings parallel some observations in cognitive aging. Additionally, following SD, attended houses were not significantly better recognized than ignored houses in a post-experiment test of recognition memory contrasting with the finding of superior recognition of attended houses in the well-rested state. These results provide evidence for co-encoding of distracting information with targets into memory when one is sleep deprived.

  2. Suppression of caspase-11 expression by histone deacetylase inhibitors

    SciTech Connect

    Heo, Hyejung; Yoo, Lang; Shin, Ki Soon; Kang, Shin Jung

    2009-01-02

    It has been well documented that histone deacetylase inhibitors suppress inflammatory gene expression. Therefore, we investigated whether histone deacetylase inhibitors modulate the expression of caspase-11 that is known as an inducible caspase regulating both inflammation and apoptosis. In the present study, we show that sodium butyrate and trichostatin A, two structurally unrelated inhibitors of histone deacetylase (HDAC), effectively suppressed the induction of caspase-11 in mouse embryonic fibroblasts stimulated with lipopolysaccharides. Sodium butyrate inhibited the activation of upstream signaling events for the caspase-11 induction such as activation of p38 mitogen-activated protein kinase and c-Jun N-terminal kinase, degradation of inhibitor of {kappa}B, and activation of nuclear factor-{kappa}B. These results suggest that the HDAC inhibitor suppressed cytosolic signaling events for the induction of caspase-11 by inhibiting the deacetylation of non-histone proteins.

  3. Whistles with a Generic Sidebranch: Production and Suppression

    NASA Astrophysics Data System (ADS)

    SELAMET, A.; KURNIAWAN, D.; KNOTTS, B. D.; NOVAK, J. M.

    2002-02-01

    The present study investigates experimentally the production and suppression of whistle noise resulting from the shear layer instabilities coupled with the acoustic resonances at the interface of two ducts, a main duct and connecting sidebranch. A generic sidebranch adapter is built to allow for mounting downstream of the throttle body in the induction system of a production engine, and the adjustment of sidebranch length. The adapter has also the provision to investigate a number of suppression methods such as: (1) ramps mounted in the main duct right upstream of the sidebranch opening; (2) a spacer to increase the distance between the throttle plate and sidebranch opening; and (3) the rotation of the throttle body from its original position. Experiments with the same hardware are conducted in both a flow laboratory and an engine dynamometer facility. The effectiveness of these suppression techniques is examined experimentally along with the correlation between the two facilities.

  4. Suppression of Collisionless Magnetic Reconnection in Asymmetric Current Sheets

    NASA Technical Reports Server (NTRS)

    Liu, Yi-Hsin; Hesse, Michael

    2016-01-01

    Using fully kinetic simulations, we study the suppression of asymmetric reconnection in the limit where the diamagnetic drift speed >> Alfven speed and the magnetic shear angle is moderate. We demonstrate that the slippage between electrons and the magnetic flux mitigates the suppression and can even result in fast reconnection that lacks one of the outflow jets. Through comparing a case where the diamagnetic drift is supported by the temperature gradient with a companion case that has a density gradient instead, we identify a robust suppression mechanism. The drift of the x-line is slowed down locally by the asymmetric nature of the x-line, and then the x-line is run over and swallowed by the faster-moving following flux.

  5. Special regulatory T cell review: The suppression problem!

    PubMed Central

    Waldmann, Herman

    2008-01-01

    The concept of T-cell mediated suppression evolved more than 30 years ago. At that time it spawned many claims that have not stood the test of time. The rediscovery of suppression phenomena and regulatory T cells over the past 15 years created schizophrenic responses amongst immunologists. Some claimed that the new proponents of suppression were, once again, bringing immunology into disrepute, whilst others have embraced the field with great enthusiasm and novel approaches to clarification. Without faithful repetition of the “old” experiments, it is difficult to establish what was right and what was wrong. Nevertheless, immunologists must now accept that a good number of the old claims were overstated, and reflected poor scientific discipline. “I speak not to disprove what Brutus spoke, But here I am to speak what I do know” Shakespeare. Julius Caesar Act 3, Scene 2. PMID:18154612

  6. Technology Assessment of Dust Suppression Techniques Applied During Structural Demolition

    SciTech Connect

    Boudreaux, J.F.; Ebadian, M.A.; Williams, P.T.; Dua, S.K.

    1998-10-20

    Hanford, Fernald, Savannah River, and other sites are currently reviewing technologies that can be implemented to demolish buildings in a cost-effective manner. In order to demolish a structure properly and, at the same time, minimize the amount of dust generated from a given technology, an evaluation must be conducted to choose the most appropriate dust suppression technology given site-specific conditions. Thus, the purpose of this research, which was carried out at the Hemispheric Center for Environmental Technology (HCET) at Florida International University, was to conduct an experimental study of dust aerosol abatement (dust suppression) methods as applied to nuclear D and D. This experimental study targeted the problem of dust suppression during the demolition of nuclear facilities. The resulting data were employed to assist in the development of mathematical correlations that can be applied to predict dust generation during structural demolition.

  7. Stroop interference and negative priming (NP) suppression in normal aging.

    PubMed

    Mayas, J; Fuentes, L J; Ballesteros, S

    2012-01-01

    Age-related differences in the reduction of Stroop interference were explored by comparing the performance of 18 younger (of mean age: 30.0±3.9 years) and 18 older healthy adults (of mean age: 75±7.2 years) in a color-word Stroop task. The aim of this study was to determine whether a decrease in the efficiency of inhibitory mechanisms associated with aging could account for age-related differences in the ability to suppress a pre-potent response. Participants performed a Stroop task to assess Stroop interference and NP suppression concurrently. Results showed a greater Stroop interference in older than in young adults. On the other hand, the NP effect was only reliable in the younger group, the older group not showing NP suppression. These findings suggest that the slowing hypothesis alone cannot explain this pattern of results and that the age-related differences must also involve an inhibitory breakdown during aging.

  8. Binocular vision in amblyopia: structure, suppression and plasticity.

    PubMed

    Hess, Robert F; Thompson, Benjamin; Baker, Daniel H

    2014-03-01

    The amblyopic visual system was once considered to be structurally monocular. However, it now evident that the capacity for binocular vision is present in many observers with amblyopia. This has led to new techniques for quantifying suppression that have provided insights into the relationship between suppression and the monocular and binocular visual deficits experienced by amblyopes. Furthermore, new treatments are emerging that directly target suppressive interactions within the visual cortex and, on the basis of initial data, appear to improve both binocular and monocular visual function, even in adults with amblyopia. The aim of this review is to provide an overview of recent studies that have investigated the structure, measurement and treatment of binocular vision in observers with strabismic, anisometropic and mixed amblyopia.

  9. Habitat Management to Suppress Pest Populations: Progress and Prospects.

    PubMed

    Gurr, Geoff M; Wratten, Steve D; Landis, Douglas A; You, Minsheng

    2017-01-31

    Habitat management involving manipulation of farmland vegetation can exert direct suppressive effects on pests and promote natural enemies. Advances in theory and practical techniques have allowed habitat management to become an important subdiscipline of pest management. Improved understanding of biodiversity-ecosystem function relationships means that researchers now have a firmer theoretical foundation on which to design habitat management strategies for pest suppression in agricultural systems, including landscape-scale effects. Supporting natural enemies with shelter, nectar, alternative prey/hosts, and pollen (SNAP) has emerged as a major research topic and applied tactic with field tests and adoption often preceded by rigorous laboratory experimentation. As a result, the promise of habitat management is increasingly being realized in the form of practical worldwide implementation. Uptake is facilitated by farmer participation in research and is made more likely by the simultaneous delivery of ecosystem services other than pest suppression.

  10. Suppression of autophagy exacerbates Mefloquine-mediated cell death.

    PubMed

    Shin, Ji Hyun; Park, So Jung; Jo, Yoon Kyung; Kim, Eun Sung; Kang, Hee; Park, Ji-Ho; Lee, Eunjoo H; Cho, Dong-Hyung

    2012-05-02

    Mefloquine is an effective treatment drug for malaria. However, it can cause several adverse side effects, and the precise mechanism associated with the adverse neurological effects of Mefloquine is not clearly understood. In this study, we investigated the effect of Mefloquine on autophagy in neuroblastoma cells. Mefloquine treatment highly induced the formation of autophagosomes and the conversion of LC3I into LC3II. Moreover, Mefloquine-induced autophagy was efficiently suppressed by an autophagy inhibitor and by down regulation of ATG6. The autophagy was also completely blocked in ATG5 deficient mouse embryonic fibroblast cells. Moreover, suppression of autophagy significantly intensified Mefloquine-mediated cytotoxicity in SH-SY5Y cells. Our findings suggest that suppression of autophagy may exacerbate Mefloquine toxicity in neuroblastoma cells.

  11. Suppression of Rayleigh-scattering-induced noise in OEOs.

    PubMed

    Okusaga, Olukayode; Cahill, James P; Docherty, Andrew; Menyuk, Curtis R; Zhou, Weimin; Carter, Gary M

    2013-09-23

    Optoelectronic oscillators (OEOs) are hybrid RF-photonic devices that promise to be environmentally robust high-frequency RF sources with very low phase noise. Previously, we showed that Rayleigh-scattering-induced noise in optical fibers coupled with amplitude-to-phase noise conversion in photodetectors and amplifiers leads to fiber-length-dependent noise in OEOs. In this work, we report on two methods for the suppression of this fiber-length-dependent noise: altering the amplitude-dependent phase delay of the OEO loops and suppressing the Rayleigh-scattering-induced noise in optical fibers. We report a 20 dB reduction in the flicker phase noise of a 6 km OEO via these suppression techniques.

  12. Regulatory T cells require TCR signaling for their suppressive function.

    PubMed

    Schmidt, Amanda M; Lu, Wen; Sindhava, Vishal J; Huang, Yanping; Burkhardt, Janis K; Yang, Enjun; Riese, Matthew J; Maltzman, Jonathan S; Jordan, Martha S; Kambayashi, Taku

    2015-05-01

    Regulatory T cells (Tregs) are a subset of CD4(+) T cells that maintain immune tolerance in part by their ability to inhibit the proliferation of conventional CD4(+) T cells (Tconvs). The role of the TCR and the downstream signaling pathways required for this suppressive function of Tregs are not fully understood. To yield insight into how TCR-mediated signals influence Treg suppressive function, we assessed the ability of Tregs with altered TCR-mediated signaling capacity to inhibit Tconv proliferation. Mature Tregs deficient in Src homology 2 domain containing leukocyte protein of 76 kDa (SLP-76), an adaptor protein that nucleates the proximal signaling complex downstream of the TCR, were unable to inhibit Tconv proliferation, suggesting that TCR signaling is required for Treg suppressive function. Moreover, Tregs with defective phospholipase C γ (PLCγ) activation due to a Y145F mutation of SLP-76 were also defective in their suppressive function. Conversely, enhancement of diacylglycerol-mediated signaling downstream of PLCγ by genetic ablation of a negative regulator of diacylglycerol kinase ζ increased the suppressive ability of Tregs. Because SLP-76 is also important for integrin activation and signaling, we tested the role of integrin activation in Treg-mediated suppression. Tregs lacking the adaptor proteins adhesion and degranulation promoting adapter protein or CT10 regulator of kinase/CT10 regulator of kinase-like, which are required for TCR-mediated integrin activation, inhibited Tconv proliferation to a similar extent as wild-type Tregs. Together, these data suggest that TCR-mediated PLCγ activation, but not integrin activation, is required for Tregs to inhibit Tconv proliferation.

  13. Noise Suppression for Dual-Energy CT through Entropy Minimization

    PubMed Central

    Petrongolo, Michael; Zhu, Lei

    2015-01-01

    In dual energy CT (DECT), noise amplification during signal decomposition significantly limits the utility of basis material images. Since clinically relevant objects typically contain a limited number of different materials, we propose an Image-domain Decomposition method through Entropy Minimization (IDEM) for noise suppression in DECT. Pixels of decomposed images are first linearly transformed into 2D clusters of data points, which are highly asymmetric due to strong signal correlation. An optimal axis is identified in the 2D space via numerical search such that the projection of data clusters onto the axis has minimum entropy. Noise suppression is performed on each image pixel by estimating the center-of-mass value of each data cluster along the direction perpendicular to the projection axis. The IDEM method is distinct from other noise suppression techniques in that it does not suppress pixel noise by reducing spatial variation between neighboring pixels. As supported by studies on Catphan©600 and anthropomorphic head phantoms, this feature endows our algorithm with a unique capability of reducing noise standard deviation on DECT decomposed images by approximately one order of magnitude while preserving spatial resolution and image noise power spectra (NPS). Compared with a filtering method and recently developed iterative method at the same level of noise suppression, the IDEM algorithm obtains high-resolution images with less artifacts. It also maintains accuracy of electron density measurements with less than 2% bias error. The IDEM method effectively suppresses noise of DECT for quantitative use, with appealing features on preservation of image spatial resolution and NPS. PMID:25955585

  14. Noise Suppression for Dual-Energy CT Through Entropy Minimization.

    PubMed

    Petrongolo, Michael; Zhu, Lei

    2015-11-01

    In dual energy CT (DECT), noise amplification during signal decomposition significantly limits the utility of basis material images. Since clinically relevant objects typically contain a limited number of different materials, we propose an Image-domain Decomposition method through Entropy Minimization (IDEM) for noise suppression in DECT. Pixels of decomposed images are first linearly transformed into 2D clusters of data points, which are highly asymmetric due to strong signal correlation. An optimal axis is identified in the 2D space via numerical search such that the projection of data clusters onto the axis has minimum entropy. Noise suppression is performed on each image pixel by estimating the center-of-mass value of each data cluster along the direction perpendicular to the projection axis. The IDEM method is distinct from other noise suppression techniques in that it does not suppress pixel noise by reducing spatial variation between neighboring pixels. As supported by studies on Catphan©600 and anthropomorphic head phantoms, this feature endows our algorithm with a unique capability of reducing noise standard deviation on DECT decomposed images by approximately one order of magnitude while preserving spatial resolution and image noise power spectra (NPS). Compared with a filtering method and recently developed iterative method at the same level of noise suppression, the IDEM algorithm obtains high-resolution images with less artifacts. It also maintains accuracy of electron density measurements with less than 2% bias error. The IDEM method effectively suppresses noise of DECT for quantitative use, with appealing features on preservation of image spatial resolution and NPS.

  15. Lateral suppression of mesopic rod and cone flicker detection

    PubMed Central

    Cao, Dingcai; Lu, Yolanda H.

    2012-01-01

    This study investigated the mechanisms of flicker detection suppression by measuring mesopic rod and cone critical flicker frequencies (CFFs) at different center and surround illuminance levels. Stimuli were generated with a four-primary photostimulator that provided independent control of rod and cone excitations. The results showed that dim surrounds ≤0.2 Td suppressed cone-mediated CFFs at ≥20 Td but not rod-mediated CFFs. These results can be understood in terms of peak amplitudes of photoreceptor impulse response functions under different stimulation conditions. PMID:22330377

  16. Hydrogen flame suppression by CF{sub 3}I

    SciTech Connect

    Mcllory, A.; Brady, B.; Marshall, P.

    1998-03-01

    Halons have long been the fire suppressants of choice for applications requiring high performance. However, halons are linked to the stratospheric ozone depletion problem. The most common halon, 1301 or CF{sub 3}Br, has an ozone depletion potential (ODP) 11 times higher than the most common chlorofluorocarbon (CFC) refrigerant. This has led to a ban on halon production under the Clean Air Act legislation in the US following the Montreal Protocols on ozone depleting substances. Halon replacements are being actively sought for new fire suppression systems and to retrofit existing systems as the current supply of halons is exhausted. One promising replacement is CF{sub 3}I. This compound has been shown to have fire suppression performance similar to that achieved for halon 1301, but with a very low ODP. Unlike halon 1301, CF{sub 3}I rapidly photolyzes in the troposphere, and thus has a tropospheric lifetime of less than two days. However, CF{sub 3}I is not the perfect replacement; it has performed poorly in cardiac sensitization studies and is approved only for total flooding applications in unoccupied spaces and streaming applications. In this study, they seek to build a model for the suppression of hydrogen fires by CF{sub 3}I. From a fundamental viewpoint, the hydrogen combustion mechanism is appealing because it is the simplest and best characterized of all combustion mechanisms, and an important sub-mechanism of all hydrocarbon combustion mechanisms. Thus, a high-performance hydrogen fire suppressant would almost certainly be an excellent suppressant for most other common fires. One-dimensional, laminar flame calculations are used to determine the major fire suppression mechanisms of CF{sub 3}I. The remainder of the paper is organized as follows: first, the model is described in detail; second, the experimental method and results are presented and finally, the authors compare the model and experimental results and discuss the major reaction pathways and

  17. IBS suppression lattice in RHIC: theory and experimental verification

    SciTech Connect

    Fedotov,A.V.; Bai, M.; Bruno, D.; Cameron, P.; Connolly, R.; Cupolo, J.; Della Penna, A.; Drees, A.; Fischer, W.; Ganetis, G.; Hoff, L.; Litvinenko, V.N.; Louie, W.; Luo, Y.; Malitsky, N.; Marr, G.; Marusic, A.; Montag, C.; Ptitsyn, V.; Roser, T.; Satogata, T.; Tepikian, S.; Trbojevic, D.; Tsoupas, N.

    2008-08-25

    Intra-beam scattering (IBS) is the limiting factor of the luminosity lifetime for Relativistic Heavy Ion Collider (RHIC) operation with heavy ions. Over the last few years the process of IBS was carefully studied in RHIC with dedicated IBS measurements and their comparison with the theoretical models. A new lattice was recently designed and implemented in RHIC to suppress transverse IBS growth, which lowered the average arc dispersion by about 20% [1]. This lattice became operational during RHIC Run-8. We review the IBS suppression mechanism, IBS measurements before and after the lattice change, and comparisons with predictions.

  18. On similarity of jet quenching and charmonia suppression

    NASA Astrophysics Data System (ADS)

    Spousta, Martin

    2017-04-01

    We quantify the magnitude and the color charge dependence of the medium induced parton energy loss in lead-lead collisions at the LHC using the data on inclusive jet suppression. The extracted color charge dependence shows that the difference between the in-medium loss of quarks and gluons is consistent with the difference between the radiation of quarks and gluons in the vacuum. Then, we examine the energy loss of prompt charmonia and we point to a remarkable similarity between the quenching of light-quark-initiated jets and the prompt charmonia suppression. Finally, we discuss possible sources of this similarity.

  19. Valve replacement for appetite suppressant-induced valvular heart disease.

    PubMed

    Biswas, S S; Donovan, C L; Forbess, J M; Royal, S H; Landolfo, K P

    1999-06-01

    Valvular heart disease associated with the use of appetite-suppressant medication is a recently described clinical entity. Although the mechanism of valvular injury remains elusive pathologically, the valvular abnormalities resemble those observed in carcinoid syndrome. The incidence of clinically evident valvular heart disease is low with short-term (less than 3 months) exposure to appetite-suppressant drugs. Prolonged exposure to higher doses in addition to combination drug therapy confers an excess risk for valvular pathologic changes. We report the case of a patient with severe mitral regurgitation who had short-term exposure (3 weeks) to the combination of fenfluramine (20 mg) and phenteramine (15 mg).

  20. Social class affects Mu-suppression during action observation.

    PubMed

    Varnum, Michael E W; Blais, Chris; Brewer, Gene A

    2016-01-01

    Socioeconomic status (SES) has been linked to differences in the degree to which people are attuned to others. Those who are lower in SES also tend to be more interpersonally attuned. However, to date, this work has not been demonstrated using neural measures. In the present electroencephalogram study, we found evidence that lower SES was linked to stronger Mu-suppression during action observation. This finding adds to the growing literature on factors that affect Mu-suppression and suggests that the mirror neuron system may be influenced by one's social class.

  1. Bottomonia suppression in an anisotropic quark-gluon plasma

    NASA Astrophysics Data System (ADS)

    Ryblewski, Radoslaw

    2017-03-01

    A brief review of recent studies on suppression of bottomonia in an anisotropic quark-gluon plasma created in heavy-ion collisions at the LHC is presented. A reasonable agreement between the model predictions for the inclusive RAA suppression factor and the preliminary CMS experimental data is found. The values of the shear viscosity to the entropy density ratio extracted from the comparison with the data lie between one and two times the gauge/gravity duality lower bound. These values agree very well with the fluid dynamical fits to the light hadron correlation data and confirm that the quark-gluon plasma is a nearly-perfect fluid.

  2. Suppressing the QCD axion abundance by hidden monopoles

    NASA Astrophysics Data System (ADS)

    Kawasaki, Masahiro; Takahashi, Fuminobu; Yamada, Masaki

    2016-02-01

    We study the Witten effect of hidden monopoles on the QCD axion dynamics, and show that its abundance as well as isocurvature perturbations can be significantly suppressed if there is a sufficient amount of hidden monopoles. When the hidden monopoles make up a significant fraction of dark matter, the Witten effect suppresses the abundance of axion with the decay constant smaller than 1012GeV. The cosmological domain wall problem of the QCD axion can also be avoided, relaxing the upper bound on the decay constant when the Peccei-Quinn symmetry is spontaneously broken after inflation.

  3. Suppression of Beneficial Mutations in Dynamic Microbial Populations

    NASA Astrophysics Data System (ADS)

    Bittihn, Philip; Hasty, Jeff; Tsimring, Lev S.

    2017-01-01

    Quantitative predictions for the spread of mutations in bacterial populations are essential to interpret evolution experiments and to improve the stability of synthetic gene circuits. We derive analytical expressions for the suppression factor for beneficial mutations in populations that undergo periodic dilutions, covering arbitrary population sizes, dilution factors, and growth advantages in a single stochastic model. We find that the suppression factor grows with the dilution factor and depends nontrivially on the growth advantage, resulting in the preferential elimination of mutations with certain growth advantages. We confirm our results by extensive numerical simulations.

  4. Suppression Of Range Sidelobes In Spaceborne Rain-Mapping Radar

    NASA Technical Reports Server (NTRS)

    Im, Eastwood; Wilson, William J.; Li, Fuk K.; Tanner, Alan B.; Durden, Stephen L.; Denning, Richard F.

    1994-01-01

    Adequate suppression of range sidelobes in chirp pulse-compression radar system for spaceborne rain-mapping application demonstrated in operation of aircraft version of system. Radar system operates at center frequency of 13.8 GHz, developed for operation aboard NASA DC-8 aircraft to measure vertical rainfall-rate profiles and rain-cell dimensions. Sidelobes suppressed by at least 55 dB. Technique applied to other frequencies, therefore, useful in other radar systems in which low sidelobes at mid to far range needed.

  5. NASA Instep/mdmsc Jitter Suppression Experiment (JITTER)

    NASA Technical Reports Server (NTRS)

    White, Edward V.

    1992-01-01

    The objectives are the following: (1) to develop and demonstrate in-space performance of both passive and active damping systems for suppression of micro-amplitude vibration on an actual application structure and operate despite uncertain dynamics and uncertain disturbance characteristics; and (2) to correlate ground and in-space performance - the performance metric is vibration attenuation. The goals are to achieve vibration suppression equivalent to 5 percent passive damping in selected models and 15 percent active damping in selected modes. Various aspects of this experiment are presented in viewgraph form.

  6. Multi-block poloxamer surfactants suppress aggregation of denatured proteins.

    PubMed

    Mustafi, Devkumar; Smith, Catherine M; Makinen, Marvin W; Lee, Raphael C

    2008-01-01

    On the basis of elastic light scattering, we have compared the capacity of the multi-block, surfactant copolymers Poloxamer 108 (P108), Poloxamer 188 (P188), and Tetronic 1107 (T1107), of average molecular weight 4700, 8400, and 15,000, respectively, with that of polyethylene glycol (PEG, molecular weight 8000) to suppress aggregation of heat-denatured hen egg white lysozyme (HEWL) and bovine serum albumin (BSA). We also compared the capacity of P188 to that of PEG to suppress aggregation of carboxypeptidase A denatured in the presence of trifluoroethanol and to facilitate recovery of catalytic activity. In contrast to the multi-block copolymers, PEG had no effect in inhibiting aggregation of HEWL or of carboxypeptidase A with the recovery of catalytic activity. At very high polymer:protein ratios (>or=10:1), PEG increased aggregation of heat-denatured HEWL and BSA, consistent with its known properties to promote macromolecular crowding and crystallization of proteins. At a polymer:protein ratio of 2:1, the tetra-block copolymer T1107 was the most effective of the three surfactant copolymers, completely suppressing aggregation of heat-denatured HEWL. At a T1107:BSA ratio of 10:1, the poloxamer suppressed aggregation of heat-denatured BSA by 50% compared to that observed in the absence of the polymer. We showed that the extent of suppression of aggregation of heat-denatured proteins by multi-block surfactant copolymers is dependent on the size of the protein and the copolymer:protein molar ratio. We also concluded that at least one of the tertiary nitrogens in the ethylene-1,2-diamine structural core of the T1107 copolymer is protonated, and that this electrostatic factor underlies its capacity to suppress aggregation of denatured proteins more effectively than nonionic, multi-block poloxamers. These results indicate that amphiphilic, surfactant, multi-block copolymers are efficient as additives to suppress aggregation and to facilitate refolding of denatured

  7. Alumina Paste Sublimation Suppression Barrier for Thermoelectric Device

    NASA Technical Reports Server (NTRS)

    Paik, Jong-Ah (Inventor); Caillat, Thierry (Inventor)

    2014-01-01

    Alumina as a sublimation suppression barrier for a Zintl thermoelectric material in a thermoelectric power generation device operating at high temperature, e.g. at or above 1000K, is disclosed. The Zintl thermoelectric material may comprise Yb.sub.14MnSb.sub.11. The alumina may be applied as an adhesive paste dried and cured on a substantially oxide free surface of the Zintl thermoelectric material and polished to a final thickness. The sublimation suppression barrier may be finalized by baking out the alumina layer on the Zintl thermoelectric material until it becomes substantially clogged with ytterbia.

  8. Studies onPaecilomyces marquandii from nematode suppressive chinampa soils.

    PubMed

    Marban-Mendoza, N; Garcia-E, R; Dicklow, M B; Zuckerman, B M

    1992-05-01

    Two applications of isolates ofPaecilomyces marquandii from suppressive chinampa soils or P. lilacinus from Peru, fungi that parasitize nematode eggs, generally gave better control of tomato root-knot due toMeloidogyne incognita than did a single application. The effects on root galling by each of thePaecilomyces isolates varied between experiments; however, the ovicidal potential of the three isolates did not differ significantly. Proteins specific for each of the isolates were demonstrated by SDS gel electrophoresis. The results indicate thatP. marquandii is one of the natural soil organisms that contribute to nematode suppression in the chinampa agricultural soils.

  9. Suppression of plant parasitic nematodes in the chinampa agricultural soils.

    PubMed

    Zuckerman, B M; Dicklow, M B; Coles, G C; Garcia-E, R; Marban-Mendoza, N

    1989-06-01

    Soil from the chinampa agricultural system in the Valley of Mexico suppressed damage by plant-parasitic nematodes to tomatoes and beans in greenhouse and growth chamber trials. Sterilization of the chinampa soil resulted in a loss of the suppressive effect, thereby indicating that one or more biotic factors were responsible for the low incidence of nematode damage. Nine organisms were isolated from chinampa soil, which showed antinematodal properties in culture. Naturally occurring populations of plant-parasitic nematodes were of lower incidence in chinampa soil than in Chapingo soil.

  10. Distinct Mechanisms for Distractor Suppression and Target Facilitation

    PubMed Central

    Adamian, Nika; Pike, Alexandra; Printzlau, Frida; Crittenden, Ben M.; Stokes, Mark G.

    2016-01-01

    It is well established that preparatory attention improves processing of task-relevant stimuli. Although it is often more important to ignore task-irrelevant stimuli, comparatively little is known about preparatory attentional mechanisms for inhibiting expected distractions. Here, we establish that distractor inhibition is not under the same top-down control as target facilitation. Using a variant of the Posner paradigm, participants were cued to either the location of a target stimulus, the location of a distractor, or were provided no predictive information. In Experiment 1, we found that participants were able to use target-relevant cues to facilitate target processing in both blocked and flexible conditions, but distractor cueing was only effective in the blocked version of the task. In Experiment 2, we replicate these findings in a larger sample and leveraged the additional statistical power to perform individual differences analyses to tease apart potential underlying mechanisms. We found no evidence for a correlation between these two types of benefit, suggesting that flexible target cueing and distractor suppression depend on distinct cognitive mechanisms. In Experiment 3, we use EEG to show that preparatory distractor suppression is associated with a diminished P1, but we found no evidence to suggest that this effect was mediated by top-down control of oscillatory activity in the alpha band (8–12 Hz). We conclude that flexible top-down mechanisms of cognitive control are specialized for target-related attention, whereas distractor suppression only emerges when the predictive information can be derived directly from experience. This is consistent with a predictive coding model of expectation suppression. SIGNIFICANCE STATEMENT If you were told to ignore a white bear, you might find it quite difficult. Holding something in working memory is thought to automatically facilitate feature processing, even if doing so is detrimental to the current task. Despite

  11. Adaptive suppression of subordinate reproduction in cooperative mammals.

    PubMed

    Clutton-Brock, Tim H; Hodge, Sarah J; Flower, Tom P; Spong, Goran F; Young, Andrew J

    2010-11-01

    Attempts to account for observed variation in the degree of reproductive skew among cooperative breeders have usually assumed that subordinate breeding has fitness costs to dominant females. They argue that dominant females concede reproductive opportunities to subordinates to retain them in the group or to dissuade them from challenging for the dominant position or that subordinate females breed where dominants are incapable of controlling them. However, an alternative possibility is that suppressing subordinate reproduction has substantive costs to the fitness of dominant females and that variation in these costs generates differences in the net benefits of suppression to dominants which are responsible for variation in the frequency of subordinate breeding that is not a consequence of either reproductive concessions or limitations in dominant control. Here, we show that, in wild Kalahari meerkats (Suricata suricatta), the frequency with which dominants evict subordinates or kill their pups varies with the costs and benefits to dominants of suppressing subordinate breeding, including the dominants' reproductive status, the size of their group, and the relatedness of subordinates. We review evidence from other studies that the suppression of reproduction by subordinates varies with the likely costs of subordinate breeding to dominants.

  12. Alfalfa suppression of weeds is affected by preceding crop

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic producers are seeking alternative tactics for weed control so that they can reduce their need for tillage. In this study, we examined the impact of the preceding crop on alfalfa suppression of weeds. Alfalfa was most competitive with weeds following soybean. When following spring wheat, v...

  13. Fission-suppressed hybrid reactor: the fusion breeder

    SciTech Connect

    Moir, R.W.; Lee, J.D.; Coops, M.S.

    1982-12-01

    Results of a conceptual design study of a /sup 233/U-producing fusion breeder are presented. The majority of the study was devoted to conceptual design and evaluation of a fission-suppressed blanket and to fuel cycle issues such as fuel reprocessing, fuel handling, and fuel management. Studies in the areas of fusion engineering, reactor safety, and economics were also performed.

  14. 30 CFR 75.1107 - Fire suppression devices.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Fire-Resistant Hydraulic Fluids on Underground Equipment § 75.1107 Fire suppression devices. On and... be installed on unattended underground equipment and suitable fire-resistant hydraulic fluids approved by the Secretary shall be used in the hydraulic systems of such equipment. Such fluids shall...

  15. 30 CFR 75.1107 - Fire suppression devices.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Fire-Resistant Hydraulic Fluids on Underground Equipment § 75.1107 Fire suppression devices. On and... be installed on unattended underground equipment and suitable fire-resistant hydraulic fluids approved by the Secretary shall be used in the hydraulic systems of such equipment. Such fluids shall...

  16. 30 CFR 75.1107 - Fire suppression devices.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Fire-Resistant Hydraulic Fluids on Underground Equipment § 75.1107 Fire suppression devices. On and... be installed on unattended underground equipment and suitable fire-resistant hydraulic fluids approved by the Secretary shall be used in the hydraulic systems of such equipment. Such fluids shall...

  17. Extra focal convective suppressing solar collector. Final technical progress report

    SciTech Connect

    1996-05-01

    This progress report describes work done on the Extra Focal Convective Suppressing Solar Collector. The topics of the report include sensor refinement for the tracking electronics, tracking controller refinement, system optics evaluation, absorber system material evaluation and performance, tracking hardware evaluation and refinement, and full scale prototype construction and testing.

  18. Global Enhancement but Local Suppression in Feature-based Attention.

    PubMed

    Forschack, Norman; Andersen, Søren K; Müller, Matthias M

    2017-04-01

    A key property of feature-based attention is global facilitation of the attended feature throughout the visual field. Previously, we presented superimposed red and blue randomly moving dot kinematograms (RDKs) flickering at a different frequency each to elicit frequency-specific steady-state visual evoked potentials (SSVEPs) that allowed us to analyze neural dynamics in early visual cortex when participants shifted attention to one of the two colors. Results showed amplification of the attended and suppression of the unattended color as measured by SSVEP amplitudes. Here, we tested whether the suppression of the unattended color also operates globally. To this end, we presented superimposed flickering red and blue RDKs in the center of a screen and a red and blue RDK in the left and right periphery, respectively, also flickering at different frequencies. Participants shifted attention to one color of the superimposed RDKs in the center to discriminate coherent motion events in the attended from the unattended color RDK, whereas the peripheral RDKs were task irrelevant. SSVEP amplitudes elicited by the centrally presented RDKs confirmed the previous findings of amplification and suppression. For peripherally located RDKs, we found the expected SSVEP amplitude increase, relative to precue baseline when color matched the one of the centrally attended RDK. We found no reduction in SSVEP amplitude relative to precue baseline, when the peripheral color matched the unattended one of the central RDK, indicating that, while facilitation in feature-based attention operates globally, suppression seems to be linked to the location of focused attention.

  19. Suppression of the Immune Response by Synthetic Adjuvants.

    DTIC Science & Technology

    1984-08-24

    RD-R145 073 SUPPRESSION OF THE IMMUNE RESPONSE BY’ SYNTHETIC / ADJUYANT5(U) MINNESOTA UNIV DULUTH DEPT OF MEDICAL MICROBIOLOGY AND IMMUNOLOGY A G...Ph.D. N00014-82-K-0635 9. PERFORMING ORGANIZATION NAME AND ADDIRESS 10. PROGRAM ELEME7T. PROJECT. TASK () Dept. of Medical Microbiology /ImmunologyARA

  20. Suppression of the Immune Response by Synthetic Adjuvants.

    DTIC Science & Technology

    1984-02-28

    D-Ai138 561 SUPPRESSION OF THE IMIMUNE RESPONSE BY SYNTHETIC / ADJUVANTS4U) MINNESOTA UNIV DULUTH DEPT OF MEDICAL MICROBIOLOGY AND IMMUNOLOGY 8 G...PERFORMING ORGANIZATION NAE ANO AORESS A. PROAM ORKE. PUNJTN CTU TA Dept. of Medical Microbiology /Immunology University of Minnesota, Duluth, MN 55812 NR 666

  1. Dynamical bottomonium-suppression in a realistic AA background

    NASA Astrophysics Data System (ADS)

    Gossiaux, P.-B.; Katz, R.

    2017-01-01

    We refine our dynamical Schroedinger-Langevin scheme designed for dealing with the suppression of quarkonium states in URHIC in order to allow for feed-downs from higher states and present updated results for the RAA as a function of the centrality.

  2. 14 CFR 460.13 - Smoke detection and fire suppression.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Smoke detection and fire suppression. 460.13 Section 460.13 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING HUMAN SPACE FLIGHT REQUIREMENTS Launch and Reentry...

  3. 14 CFR 460.13 - Smoke detection and fire suppression.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Smoke detection and fire suppression. 460.13 Section 460.13 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING HUMAN SPACE FLIGHT REQUIREMENTS Launch and Reentry...

  4. 14 CFR 460.13 - Smoke detection and fire suppression.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Smoke detection and fire suppression. 460.13 Section 460.13 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING HUMAN SPACE FLIGHT REQUIREMENTS Launch and Reentry...

  5. Brain Oscillations Mediate Successful Suppression of Unwanted Memories.

    PubMed

    Waldhauser, Gerd T; Bäuml, Karl-Heinz T; Hanslmayr, Simon

    2015-11-01

    To avoid thinking of unwanted memories can be a successful strategy to forget. Studying brain oscillations as measures of local and inter-regional processing, we shed light on the neural dynamics underlying memory suppression. Employing the think/no-think paradigm, 24 healthy human subjects repeatedly retrieved (think condition) or avoided thinking of (no-think condition) a previously learned target memory upon being presented with a reminder stimulus. Think and no-think instructions were delivered by means of a precue that preceded the reminder by 1 s. This allowed us to segregate neural control mechanisms that were triggered by the precue from the effect of suppression on target memory networks after presentation of the reminder. Control effects were reflected in increased power in the theta (5-9 Hz) frequency band in the medial and dorsolateral prefrontal cortex and higher long-range alpha (10-14 Hz) phase synchronization. Successful suppression of target memories was reflected in a decrease of theta oscillatory power in the medial temporal lobes and reduced long-range theta phase synchronization emerged after presentation of the reminder. Our results suggest that intentional memory suppression correlates with increased neural communication in cognitive control networks that act in down-regulating local and inter-regional processing related to memory retrieval.

  6. AREAWIDE SUPPRESSION OF FIRE ANTS: DEMONSTRATION PROJECT IN MISSISSIPPI, 2006

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The USDA-ARS demonstration project for the suppression of imported fire ants has entered its sixth year. In 2005, Mississippi State University joined the project monitoring sites in Clay and Grenada Counties. The Areawide project integrates biological control agents with the chemical ...

  7. Suppression Pool Mixing and Condensation Tests in PUMA Facility

    SciTech Connect

    Ling Cheng; Kyoung Suk Woo; Mamoru Ishii; Jaehyok Lim; Han, James

    2006-07-01

    Condensation of steam with non-condensable in the form of jet flow or bubbly flow inside the suppression pool is an important phenomenon on determining the containment pressure of a passively safe boiling water reactor. 32 cases of pool mixing and condensation test have been performed in Purdue University Multi-Dimensional Integral Test Assembly (PUMA) facility under the sponsor of the U.S. Nuclear Regulatory Commission to investigate thermal stratification and pool mixing inside the suppression pool during the reactor blowdown period. The test boundary conditions, such as the steam flow rate, the noncondensable gas flow rate, the initial water temperature, the pool initial pressure and the vent opening submergence depth, which covers a wide range of prototype (SBWR-600) conditions during Loss of Coolant Accident (LOCA) were obtained from the RELAP5 calculation. The test results show that steam is quickly condensed at the exit of the vent opening. For pure steam injection or low noncondensable injection cases, only the portion above the vent opening in the suppression pool is heated up by buoyant plumes. The water below the vent opening can be heated up slowly through conduction. The test results also show that the degree of thermal stratification in suppression pool is affected by the vent opening submergence depth, the pool initial pressure and the steam injection rate. And it is slightly affected by the initial water temperature. From these tests it is concluded that the pool mixing is strongly affected by the noncondensable gas flow rate. (authors)

  8. Pair housing induced feeding suppression: individual housing not novelty.

    PubMed

    Lopak, V; Eikelboom, R

    Male rats that are moved from individual to pair housing suppress their feeding for a few days [O'Connor R, Eikelboom R. The effects of changes in housing on feeding and wheel running. Physiol Behav 2000;68:361-371]. The present study explored whether the suppression was a result of the period of individual housing or the novelty of the other animal. Two groups of 16 rats were pair-housed and one group of rats was individually housed for 21 days. The individually housed rats were then pair-housed (IP group) and rats in one of the pair-housed groups were re-housed with novel partners (NP group), while rats in the other pair-housed group remained with the same partner (SP group). Feeding was suppressed only for rats in the IP group, suggesting that the novelty of the partner did not suppress feeding, but rather, the change from individual to pair housing did. Water consumption was also measured, but was unaffected by the re-housing manipulation.

  9. Signal enhancement and suppression during visual-spatial selective attention.

    PubMed

    Couperus, J W; Mangun, G R

    2010-11-04

    Selective attention involves the relative enhancement of relevant versus irrelevant stimuli. However, whether this relative enhancement involves primarily enhancement of attended stimuli, or suppression of irrelevant stimuli, remains controversial. Moreover, if both enhancement and suppression are involved, whether they result from a single mechanism or separate mechanisms during attentional control or selection is not known. In two experiments using a spatial cuing paradigm with task-relevant targets and irrelevant distractors, target, and distractor processing was examined as a function of distractor expectancy. Additionally, in the second study the interaction of perceptual load and distractor expectancy was explored. In both experiments, distractors were either validly cued (70%) or invalidly cued (30%) in order to examine the effects of distractor expectancy on attentional control as well as target and distractor processing. The effects of distractor expectancy were assessed using event-related potentials recorded during the cue-to-target period (preparatory attention) and in response to the task-relevant target stimuli (selective stimulus processing). Analyses of distractor-present displays (anticipated versus unanticipated), showed modulations in brain activity during both the preparatory period and during target processing. The pattern of brain responses suggest both facilitation of attended targets and suppression of unattended distractors. These findings provide evidence for a two-process model of visual-spatial selective attention, where one mechanism (facilitation) influences relevant stimuli and another (suppression) acts to filter distracting stimuli.

  10. 65. FIRE SUPPRESSION PIPES BEHIND FLAME BUCKET. PIPES TO UMBILICAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    65. FIRE SUPPRESSION PIPES BEHIND FLAME BUCKET. PIPES TO UMBILICAL MAST IN LOWER LEFT CORNER; PIPES TO LAUNCHER IN UPPER LEFT CORNER; PIPES TO FLAME BUCKET IN LOWER RIGHT CORNER OF PHOTOGRAPH. POTABLE WATER PIPING IN UPPER RIGHT CORNER OF PHOTO. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  11. Fluorescence suppression using micro-scale spatially offset Raman spectroscopy.

    PubMed

    Conti, Claudia; Botteon, Alessandra; Colombo, Chiara; Realini, Marco; Matousek, Pavel

    2016-09-21

    We present a new concept of fluorescence suppression in Raman microscopy based on micro-spatially offset Raman spectroscopy which is applicable to thin stratified turbid (diffusely scattering) matrices permitting the retrieval of the Raman signals of sublayers below intensely fluorescing turbid over-layers. The method is demonstrated to yield good quality Raman spectra with dramatically suppressed fluorescence backgrounds enabling the retrieval of Raman sublayer signals even in situations where conventional Raman microscopy spectra are fully overwhelmed by intense fluorescence. The concept performance was studied theoretically using Monte Carlo simulations indicating the potential of up to an order or two of magnitude suppression of overlayer fluorescence backgrounds relative to the Raman sublayer signals. The technique applicability was conceptually demonstrated on layered samples involving paints, polymers and stones yielding fluorescence suppression factors between 12 to above 430. The technique has potential applications in a number of analytical areas including cultural heritage, archaeology, polymers, food, pharmaceutical, biological, biomedical, forensics and catalytic sciences and quality control in manufacture.

  12. Rosmarinus officinalis extract suppresses Propionibacterium acnes-induced inflammatory responses.

    PubMed

    Tsai, Tsung-Hsien; Chuang, Lu-Te; Lien, Tsung-Jung; Liing, Yau-Rong; Chen, Wei-Yu; Tsai, Po-Jung

    2013-04-01

    Propionibacterium acnes is a key pathogen involved in the progression of acne inflammation. The development of a new agent possessing antimicrobial and anti-inflammatory activity against P. acnes is therefore of interest. In this study, we investigated the inhibitory effect of rosemary (Rosmarinus officinalis) extract on P. acnes-induced inflammation in vitro and in vivo. The results showed that ethanolic rosemary extract (ERE) significantly suppressed the secretion and mRNA expression of proinflammatory cytokines, including interleukin (IL)-8, IL-1β, and tumor necrosis factor-α in P. acnes-stimulated monocytic THP-1 cells. In an in vivo mouse model, concomitant intradermal injection of ERE attenuated the P. acnes-induced ear swelling and granulomatous inflammation. Since ERE suppressed the P. acnes-induced nuclear factor kappa-B (NF-κB) activation and mRNA expression of Toll-like receptor (TLR) 2, the suppressive effect of ERE might be due, at least partially, to diminished NF-κB activation and TLR2-mediated signaling pathways. Furthermore, three major constituents of ERE, carnosol, carnosic acid, and rosmarinic acid, exerted different immumodulatory activities in vitro. In brief, rosmarinic acid significantly suppressed IL-8 production, while the other two compounds inhibited IL-1β production. Further study is needed to explore the role of bioactive compounds of rosemary in mitigation of P. acnes-induced inflammation.

  13. Weed suppression by grasses for orchard floor management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fruit trees in orchards of the mid-Atlantic region are often planted in vegetation-free rows alternating with grass travel alleys. The tree rows can be maintained vegetation-free by herbicides or tillage but soil degradation or tree injury can result from these practices. Grasses that suppress wee...

  14. Weed suppression by grasses for orchard floor management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fruit trees in orchards of the mid-Atlantic region of the U.S. are often planted in vegetation-free rows alternating with grass travel alleys. The tree rows can be maintained vegetation-free by herbicides or tillage, but soil degradation or tree injury can result. Grass that is managed to suppress...

  15. Silymarin Suppresses Cellular Inflammation By Inducing Reparative Stress Signaling

    PubMed Central

    Lovelace, Erica S.; Wagoner, Jessica; MacDonald, James; Bammler, Theo; Bruckner, Jacob; Brownell, Jessica; Beyer, Richard; Zink, Erika M.; Kim, Young-Mo; Kyle, Jennifer E.; Webb-Robertson, Bobbie-Jo; Waters, Katrina M.; Metz, Thomas O.; Farin, Federico; Oberlies, Nicholas H.; Polyak, Stephen J.

    2016-01-01

    Silymarin, a characterized extract of the seeds of milk thistle (Silybum marianum), suppresses cellular inflammation. To define how this occurs, transcriptional profiling, metabolomics, and signaling studies were performed in human liver and T cell lines. Cellular stress and metabolic pathways were modulated within 4 h of silymarin treatment: activation of Activating Transcription Factor 4 (ATF-4) and adenosine monophosphate protein kinase (AMPK) and inhibition of mammalian target of rapamycin (mTOR) signaling, the latter being associated with induction of DNA-damage-inducible transcript 4 (DDIT4). Metabolomics analyses revealed silymarin suppression of glycolytic, tricarboxylic acid (TCA) cycle, and amino acid metabolism. Anti-inflammatory effects arose with prolonged (i.e. 24 h) silymarin exposure, with suppression of multiple pro-inflammatory mRNAs and signaling pathways including nuclear factor kappa B (NF-κB) and forkhead box O (FOXO). Studies with murine knock out cells revealed that silymarin inhibition of both mTOR and NF-κB was partially AMPK dependent, while silymarin inhibition of mTOR required DDIT4. Other natural products induced similar stress responses, which correlated with their ability to suppress inflammation. Thus, natural products activate stress and repair responses that culminate in an anti-inflammatory cellular phenotype. Natural products like silymarin may be useful as tools to define how metabolic, stress, and repair pathways regulate cellular inflammation. PMID:26186142

  16. Suppressing the Morning Rise in Cortisol Impairs Free Recall

    ERIC Educational Resources Information Center

    Rimmele, Ulrike; Meier, Flurina; Lange, Tanja; Born, Jan

    2010-01-01

    Elevated glucocorticoid levels impair memory retrieval. We investigated whether retrieval under naturally elevated glucocorticoid levels, i.e., during the morning rise in cortisol can be improved by suppressing cortisol. In a crossover study 16 men retrieved emotional and neutral texts and pictures (learned 3 d earlier) 30 min after morning…

  17. Scientific Knowledge Suppresses but Does Not Supplant Earlier Intuitions

    ERIC Educational Resources Information Center

    Shtulman, Andrew; Valcarcel, Joshua

    2012-01-01

    When students learn scientific theories that conflict with their earlier, naive theories, what happens to the earlier theories? Are they overwritten or merely suppressed? We investigated this question by devising and implementing a novel speeded-reasoning task. Adults with many years of science education verified two types of statements as quickly…

  18. Using multiple perspectives to suppress information and complexity

    SciTech Connect

    Kelsey, R.L. |; Webster, R.B.; Hartley, R.T.

    1998-09-01

    Dissemination of battlespace information involves getting information to particular warfighters that is both useful and in a form that facilitates the tasks of those particular warfighters. There are two issues which motivate this problem of dissemination. The first issue deals with disseminating pertinent information to a particular warfighter. This can be thought of as information suppression. The second issue deals with facilitating the use of the information by tailoring the computer interface to the specific tasks of an individual warfighter. This can be thought of as interface complexity suppression. This paper presents a framework for suppressing information using an object-based knowledge representation methodology. This methodology has the ability to represent knowledge and information in multiple perspectives. Information can be suppressed by creating a perspective specific to an individual warfighter. In this way, only the information pertinent and useful to a warfighter is made available to that warfighter. Information is not removed, lost, or changed, but spread among multiple perspectives. Interface complexity is managed in a similar manner. Rather than have one generalized computer interface to access all information, the computer interface can be divided into interface elements. Interface elements can then be selected and arranged into a perspective-specific interface. This is done in a manner to facilitate completion of tasks contained in that perspective. A basic battlespace domain containing ground and air elements and associated warfighters is used to exercise the methodology.

  19. Perfluorooctanoic Acid Exposure Suppresses T-independent Antibody Responses

    EPA Science Inventory

    Exposure to  3.75mg/kg of perfluoroocatnoic acid (PFOA) for 15d suppresses T-dependent antibody responses (TDAR), suggesting that T helper cells and/or B cells/plasma cells may be impacted. This study evaluated effects of PFOA exposure on the T cell-independent antibody response...

  20. Gamma-spectrometry with Compton suppressed detectors arrays

    SciTech Connect

    Schueck, C.; Hannachi, F.; Chapman, R.; Lisle, J.C.; Mo, J.N.; Paul, E.; Love, D.J.G.; Nolan, P.J.; Nelson, A.H.; Walker, P.M.

    1985-01-01

    Recent results of experiments performed with two different Compton-suppressed detectors arrays in Daresbury and Berkeley (/sup 163,164/Yb and /sup 154/Er, respectively), are presented together with a brief description of the national French array presently under construction in Strasbourg. 25 refs., 15 figs.

  1. Matairesinol inhibits angiogenesis via suppression of mitochondrial reactive oxygen species

    SciTech Connect

    Lee, Boram; Kim, Ki Hyun; Jung, Hye Jin; Kwon, Ho Jeong

    2012-04-27

    Highlights: Black-Right-Pointing-Pointer Matairesinol suppresses mitochondrial ROS generation during hypoxia. Black-Right-Pointing-Pointer Matairesinol exhibits potent anti-angiogenic activity both in vitro and in vivo. Black-Right-Pointing-Pointer Matairesinol could be a basis for the development of novel anti-angiogenic agents. -- Abstract: Mitochondrial reactive oxygen species (mROS) are involved in cancer initiation and progression and function as signaling molecules in many aspects of hypoxia and growth factor-mediated signaling. Here we report that matairesinol, a natural small molecule identified from the cell-based screening of 200 natural plants, suppresses mROS generation resulting in anti-angiogenic activity. A non-toxic concentration of matairesinol inhibited the proliferation of human umbilical vein endothelial cells. The compound also suppressed in vitro angiogenesis of tube formation and chemoinvasion, as well as in vivo angiogenesis of the chorioallantoic membrane at non-toxic doses. Furthermore, matairesinol decreased hypoxia-inducible factor-1{alpha} in hypoxic HeLa cells. These results demonstrate that matairesinol could function as a novel angiogenesis inhibitor by suppressing mROS signaling.

  2. Discrete Element Model for Suppression of Coffee-Ring Effect

    NASA Astrophysics Data System (ADS)

    Xu, Ting; Lam, Miu Ling; Chen, Ting-Hsuan

    2017-02-01

    When a sessile droplet evaporates, coffee-ring effect drives the suspended particulate matters to the droplet edge, eventually forming a ring-shaped deposition. Because it causes a non-uniform distribution of solid contents, which is undesired in many applications, attempts have been made to eliminate the coffee-ring effect. Recent reports indicated that the coffee-ring effect can be suppressed by a mixture of spherical and non-spherical particles with enhanced particle-particle interaction at air-water interface. However, a model to comprehend the inter-particulate activities has been lacking. Here, we report a discrete element model (particle system) to investigate the phenomenon. The modeled dynamics included particle traveling following the capillary flow with Brownian motion, and its resultant 3D hexagonal close packing of particles along the contact line. For particles being adsorbed by air-water interface, we modeled cluster growth, cluster deformation, and cluster combination. We found that the suppression of coffee-ring effect does not require a circulatory flow driven by an inward Marangoni flow at air-water interface. Instead, the number of new cluster formation, which can be enhanced by increasing the ratio of non-spherical particles and the overall number of microspheres, is more dominant in the suppression process. Together, this model provides a useful platform elucidating insights for suppressing coffee-ring effect for practical applications in the future.

  3. Discrete Element Model for Suppression of Coffee-Ring Effect

    PubMed Central

    Xu, Ting; Lam, Miu Ling; Chen, Ting-Hsuan

    2017-01-01

    When a sessile droplet evaporates, coffee-ring effect drives the suspended particulate matters to the droplet edge, eventually forming a ring-shaped deposition. Because it causes a non-uniform distribution of solid contents, which is undesired in many applications, attempts have been made to eliminate the coffee-ring effect. Recent reports indicated that the coffee-ring effect can be suppressed by a mixture of spherical and non-spherical particles with enhanced particle-particle interaction at air-water interface. However, a model to comprehend the inter-particulate activities has been lacking. Here, we report a discrete element model (particle system) to investigate the phenomenon. The modeled dynamics included particle traveling following the capillary flow with Brownian motion, and its resultant 3D hexagonal close packing of particles along the contact line. For particles being adsorbed by air-water interface, we modeled cluster growth, cluster deformation, and cluster combination. We found that the suppression of coffee-ring effect does not require a circulatory flow driven by an inward Marangoni flow at air-water interface. Instead, the number of new cluster formation, which can be enhanced by increasing the ratio of non-spherical particles and the overall number of microspheres, is more dominant in the suppression process. Together, this model provides a useful platform elucidating insights for suppressing coffee-ring effect for practical applications in the future. PMID:28216639

  4. Suppression of Pest Lepidoptera by Releasing Partially Sterile Males

    ERIC Educational Resources Information Center

    Knipling. E. F.

    1970-01-01

    Uses population growth models to calculate the theoretical suppression of reproduction achieved by releasing irradiated male moths carrying genetic sterility factors. Shows that releasing partially sterile males should be more effective than releasing fully sterile males. Discusses the costs and advantages of applying this approach to the control…

  5. Maturation of cognitive control: delineating response inhibition and interference suppression.

    PubMed

    Brydges, Christopher R; Anderson, Mike; Reid, Corinne L; Fox, Allison M

    2013-01-01

    Cognitive control is integral to the ability to attend to a relevant task whilst suppressing distracting information or inhibiting prepotent responses. The current study examined the development of these two subprocesses by examining electrophysiological indices elicited during each process. Thirteen 18 year-old adults and thirteen children aged 8-11 years (mean=9.77 years) completed a hybrid Go/Nogo flanker task while continuous EEG data were recorded. The N2 topography for both response inhibition and interference suppression changed with increasing age. The neural activation associated with response inhibition became increasingly frontally distributed with age, and showed decreases of both amplitude and peak latency from childhood to adulthood, possibly due to reduced cognitive demands and myelination respectively occurring during this period. Interestingly, a significant N2 effect was apparent in adults, but not observed in children during trials requiring interference suppression. This could be due to more diffuse activation in children, which would require smaller levels of activation over a larger region of the brain than is reported in adults. Overall, these results provide evidence of distinct maturational processes occurring throughout late childhood and adolescence, highlighting the separability of response inhibition and interference suppression.

  6. Evaluating the Role of Contingency in Differentially Reinforced Tic Suppression

    ERIC Educational Resources Information Center

    Himle, Michael B.; Woods, Douglas W.; Bunaciu, Liviu

    2008-01-01

    The current study evaluated the effects of tokens delivered on differential reinforcement of zero-rate behavior (DRO) schedules or noncontingently on tic suppression in 4 children with tics. Tic frequency was lower in 3 of 4 children when tokens were delivered contingent on the absence of tics than when tokens were delivered noncontingently.…

  7. Newspaper Suppression During the Mexican War, 1846-1848.

    ERIC Educational Resources Information Center

    Reilly, Tom

    A number of scholars have found that wartime conditions often bring about conflict between the press and the military. This study documents the various incidents between the United States Army and various Mexican and United States newspaper editors that led to at least ten cases of newspaper suppression, the occasional use of prior censorship, and…

  8. Expectation Suppression in Early Visual Cortex Depends on Task Set.

    PubMed

    St John-Saaltink, Elexa; Utzerath, Christian; Kok, Peter; Lau, Hakwan C; de Lange, Floris P

    2015-01-01

    Stimulus expectation can modulate neural responses in early sensory cortical regions, with expected stimuli often leading to a reduced neural response. However, it is unclear whether this expectation suppression is an automatic phenomenon or is instead dependent on the type of task a subject is engaged in. To investigate this, human subjects were presented with visual grating stimuli in the periphery that were either predictable or non-predictable while they performed three tasks that differently engaged cognitive resources. In two of the tasks, the predictable stimulus was task-irrelevant and spatial attention was engaged at fixation, with a high load on either perceptual or working memory resources. In the third task, the predictable stimulus was task-relevant, and therefore spatially attended. We observed that expectation suppression is dependent on the cognitive resources engaged by a subjects' current task. When the grating was task-irrelevant, expectation suppression for predictable items was visible in retinotopically specific areas of early visual cortex (V1-V3) during the perceptual task, but it was abolished when working memory was loaded. When the grating was task-relevant and spatially attended, there was no significant effect of expectation in early visual cortex. These results suggest that expectation suppression is not an automatic phenomenon, but dependent on attentional state and type of available cognitive resources.

  9. 47 CFR 80.217 - Suppression of interference aboard ships.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Suppression of interference aboard ships. 80.217 Section 80.217 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL... interference aboard ships. (a) A voluntarily equipped ship station receiver must not cause harmful...

  10. 47 CFR 80.217 - Suppression of interference aboard ships.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Suppression of interference aboard ships. 80.217 Section 80.217 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL... interference aboard ships. (a) A voluntarily equipped ship station receiver must not cause harmful...

  11. 47 CFR 80.217 - Suppression of interference aboard ships.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Suppression of interference aboard ships. 80.217 Section 80.217 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL... interference aboard ships. (a) A voluntarily equipped ship station receiver must not cause harmful...

  12. 47 CFR 80.217 - Suppression of interference aboard ships.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Suppression of interference aboard ships. 80.217 Section 80.217 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL... interference aboard ships. (a) A voluntarily equipped ship station receiver must not cause harmful...

  13. 47 CFR 80.217 - Suppression of interference aboard ships.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Suppression of interference aboard ships. 80.217 Section 80.217 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL... interference aboard ships. (a) A voluntarily equipped ship station receiver must not cause harmful...

  14. Nonsense Suppression as an Approach to Treat Lysosomal Storage Diseases

    PubMed Central

    Keeling, Kim M.

    2016-01-01

    In-frame premature termination codons (PTCs) (also referred to as nonsense mutations) comprise ~10% of all disease-associated gene lesions. PTCs reduce gene expression in two ways. First, PTCs prematurely terminate translation of an mRNA, leading to the production of a truncated polypeptide that often lacks normal function and/or is unstable. Second, PTCs trigger degradation of an mRNA by activating nonsense-mediated mRNA decay (NMD), a cellular pathway that recognizes and degrades mRNAs containing a PTC. Thus, translation termination and NMD are putative therapeutic targets for the development of treatments for genetic diseases caused by PTCs. Over the past decade, significant progress has been made in the identification of compounds with the ability to suppress translation termination of PTCs (also referred to as readthrough). More recently, NMD inhibitors have also been explored as a way to enhance the efficiency of PTC suppression. Due to their relatively low threshold for correction, lysosomal storage diseases are a particularly relevant group of diseases to investigate the feasibility of nonsense suppression as a therapeutic approach. In this review, the current status of PTC suppression and NMD inhibition as potential treatments for lysosomal storage diseases will be discussed. PMID:28367323

  15. New insights regarding glucocorticoids, stress and gonadotropin suppression.

    PubMed

    Breen, Kellie M; Karsch, Fred J

    2006-07-01

    This review highlights our recent work investigating the inhibitory effects of acute, physiologic stress-like increases in cortisol on reproductive neuroendocrine activity in sheep, the mechanisms responsible for this suppression, and the relevance of enhanced glucocorticoid secretion to stress-induced inhibition of gonadotropin secretion in this species. Initial studies established that cortisol rapidly suppresses pulsatile luteinizing hormone secretion. In ovariectomized ewes, this inhibition reflects the reduction of pituitary responsiveness to gonadotropin-releasing hormone mediated by the type II glucocorticoid receptor, rather than the suppression in hypothalamic gonadotropin-releasing hormone release. Studies in ovary-intact ewes, however, uncovered an alternative mode of cortisol action. During the follicular phase of the estrous cycle, cortisol reduces luteinizing hormone pulse frequency, most likely via the inhibition of gonadotropin-releasing hormone pulsatility. Recent preliminary evidence in ovariectomized ewes demonstrates increased cortisol secretion is essential for disruption of pulsatile luteinizing hormone secretion in response to a psychosocial stress. Taken together, our observations reveal diverse inhibitory actions of cortisol on gonadotropin secretion and that this glucocorticoid is not only sufficient, but necessary for suppression of reproductive neuroendocrine activity in response to certain types of stress.

  16. Coping with Fear through Suppression and Avoidance of Threatening Information

    ERIC Educational Resources Information Center

    Nielsen, Jesper; Shapiro, Stewart

    2009-01-01

    Fear appeal communications are widely used by social marketers in their efforts to persuade individuals to refrain from engaging in risky behaviors. The present research shows that exposure to a fear appeal can lead to the suppression of concepts semantically related to the threat and bias attentional resources away from threat-relevant…

  17. Enhance-Synergism and Suppression Effects in Multiple Regression

    ERIC Educational Resources Information Center

    Lipovetsky, Stan; Conklin, W. Michael

    2004-01-01

    Relations between pairwise correlations and the coefficient of multiple determination in regression analysis are considered. The conditions for the occurrence of enhance-synergism and suppression effects when multiple determination becomes bigger than the total of squared correlations of the dependent variable with the regressors are discussed. It…

  18. Managing Abiotic Factors of Compost to Increase Soilborne Disease Suppression

    ERIC Educational Resources Information Center

    Griffin, Deirdre E.

    2012-01-01

    Soilborne pathogens can devastate crops, causing economic losses for farmers due to reduced yields and expensive management practices. Fumigants and fungicides have harmful impacts on the surrounding environment and can be toxic to humans. Therefore, alternative methods of disease management are important. The disease suppressive abilities of…

  19. Hemodilution, vasopressin suppression, and diuresis during water immersion in man

    NASA Technical Reports Server (NTRS)

    Greenleaf, J. E.; Keil, L. C.; Shvartz, E.

    1981-01-01

    The possible role of hemodilution in the early stages of water immersion in the suppression of antidiuretic hormone (vasopressin) and subsequent diuresis in man is investigated. Parameters characterizing hemodilution as well as water balance and intercompartmental fluid levels were measured before, during and after the immersion of ten subjects in a semireclining position in tap water up to their necks at 34.6 C for 8 hr. Results indicate that hemodilution and the suppression of vasopressin and plasma renin activity were present by the second hour of immersion, with the early hemodilution due to a slight increase in plasma volume with no change in plasma sodium or osmotic contents, even though urine volume and osmotic excretion rates increased significantly. Hyponatremia, hyposmotemia and plasma renin activity suppression are observed to continue to the end of immersion, resulting in final decreases of 15.6% in plasma volume, 18.8% in extracellular volume, 19.6% in interstitial volume and 10.7% in red cell volume. Findings suggest the transfer of hypotonic fluid into the vascular system, which contributes to vasopressin suppression observed during immersion.

  20. Space Shuttle ice suppression system validation, volume 1

    NASA Technical Reports Server (NTRS)

    Porteiro, J. L. F.; Norton, D. J.; Pollock, T. C.

    1984-01-01

    Preliminary analytical considerations and the experimental investigation of the flow field for the desired configurations in the absence of wind effects are discussed. A wind tunnel test program to determine the effect of different wind conditions on ice suppression system (ISS) performance is also discussed.

  1. Molecular hydrogen suppresses activated Wnt/β-catenin signaling

    PubMed Central

    Lin, Yingni; Ohkawara, Bisei; Ito, Mikako; Misawa, Nobuaki; Miyamoto, Kentaro; Takegami, Yasuhiko; Masuda, Akio; Toyokuni, Shinya; Ohno, Kinji

    2016-01-01

    Molecular hydrogen (H2) is effective for many diseases. However, molecular bases of H2 have not been fully elucidated. Cumulative evidence indicates that H2 acts as a gaseous signal modulator. We found that H2 suppresses activated Wnt/β-catenin signaling by promoting phosphorylation and degradation οf β-catenin. Either complete inhibition of GSK3 or mutations at CK1- and GSK3-phosphorylation sites of β-catenin abolished the suppressive effect of H2. H2 did not increase GSK3-mediated phosphorylation of glycogen synthase, indicating that H2 has no direct effect on GSK3 itself. Knock-down of adenomatous polyposis coli (APC) or Axin1, which form the β-catenin degradation complex, minimized the suppressive effect of H2 on β-catenin accumulation. Accordingly, the effect of H2 requires CK1/GSK3-phosphorylation sites of β-catenin, as well as the β-catenin degradation complex comprised of CK1, GSK3, APC, and Axin1. We additionally found that H2 reduces the activation of Wnt/β-catenin signaling in human osteoarthritis chondrocytes. Oral intake of H2 water tended to ameliorate cartilage degradation in a surgery-induced rat osteoarthritis model through attenuating β-catenin accumulation. We first demonstrate that H2 suppresses abnormally activated Wnt/β-catenin signaling, which accounts for the protective roles of H2 in a fraction of diseases. PMID:27558955

  2. Biofumigation and soil amendment effects on cotton root rot suppression

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This serious disease of cotton grown in southwest USA can be suppressed to varying degrees. Our results indicate the following: improved plant nutrition with certain chelated trace elements; soil applications of slow release fungicides; preplant banding of high rates of powdered elemental S; use o...

  3. Natural suppression of Meloidogyne incognita by Pasteuria penetrans in cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The endospore-forming bacterium Pasteuria penetrans is an obligate parasite of root-knot nematodes (Meloidogyne spp.). This bacterium is commonly found in agricultural soils and has been associated with suppression of Meloidogyne spp. In a field site naturally infested with both P. penetrans and M...

  4. Inhibitors of nucleotidyltransferase superfamily enzymes suppress herpes simplex virus replication.

    PubMed

    Tavis, John E; Wang, Hong; Tollefson, Ann E; Ying, Baoling; Korom, Maria; Cheng, Xiaohong; Cao, Feng; Davis, Katie L; Wold, William S M; Morrison, Lynda A

    2014-12-01

    Herpesviruses are large double-stranded DNA viruses that cause serious human diseases. Herpesvirus DNA replication depends on multiple processes typically catalyzed by nucleotidyltransferase superfamily (NTS) enzymes. Therefore, we investigated whether inhibitors of NTS enzymes would suppress replication of herpes simplex virus 1 (HSV-1) and HSV-2. Eight of 42 NTS inhibitors suppressed HSV-1 and/or HSV-2 replication by >10-fold at 5 μM, with suppression at 50 μM reaching ∼1 million-fold. Five compounds in two chemical families inhibited HSV replication in Vero and human foreskin fibroblast cells as well as the approved drug acyclovir did. The compounds had 50% effective concentration values as low as 0.22 μM with negligible cytotoxicity in the assays employed. The inhibitors suppressed accumulation of viral genomes and infectious particles and blocked events in the viral replication cycle before and during viral DNA replication. Acyclovir-resistant mutants of HSV-1 and HSV-2 remained highly sensitive to the NTS inhibitors. Five of six NTS inhibitors of the HSVs also blocked replication of another herpesvirus pathogen, human cytomegalovirus. Therefore, NTS enzyme inhibitors are promising candidates for new herpesvirus treatments that may have broad efficacy against members of the herpesvirus family.

  5. 36 CFR 211.5 - Emergency fire suppression assistance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Emergency fire suppression assistance. 211.5 Section 211.5 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE... this subpart these definitions apply: (1) Prescribed fire means a fire burning under a set of...

  6. 36 CFR 211.5 - Emergency fire suppression assistance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Emergency fire suppression assistance. 211.5 Section 211.5 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE... this subpart these definitions apply: (1) Prescribed fire means a fire burning under a set of...

  7. Breast Cancer Vaccines that Overcome Tolerance and Immune Suppression

    DTIC Science & Technology

    2012-01-01

    developing breast cancer. Immune suppression induced by T-regs and MDSC is a major obstacle in immunotherapy [1, 2] . Tolerance to self antigens is another...8. 2. Ostrand-Rosenberg, S., Myeloid-derived Suppressor Cells: more mechanisms for inhibiting antitumor immunity. Cancer Immunol Immunother, 2010

  8. Rosmarinus officinalis Extract Suppresses Propionibacterium acnes–Induced Inflammatory Responses

    PubMed Central

    Tsai, Tsung-Hsien; Chuang, Lu-Te; Lien, Tsung-Jung; Liing, Yau-Rong; Chen, Wei-Yu

    2013-01-01

    Abstract Propionibacterium acnes is a key pathogen involved in the progression of acne inflammation. The development of a new agent possessing antimicrobial and anti-inflammatory activity against P. acnes is therefore of interest. In this study, we investigated the inhibitory effect of rosemary (Rosmarinus officinalis) extract on P. acnes–induced inflammation in vitro and in vivo. The results showed that ethanolic rosemary extract (ERE) significantly suppressed the secretion and mRNA expression of proinflammatory cytokines, including interleukin (IL)-8, IL-1β, and tumor necrosis factor-α in P. acnes–stimulated monocytic THP-1 cells. In an in vivo mouse model, concomitant intradermal injection of ERE attenuated the P. acnes–induced ear swelling and granulomatous inflammation. Since ERE suppressed the P. acnes–induced nuclear factor kappa-B (NF-κB) activation and mRNA expression of Toll-like receptor (TLR) 2, the suppressive effect of ERE might be due, at least partially, to diminished NF-κB activation and TLR2-mediated signaling pathways. Furthermore, three major constituents of ERE, carnosol, carnosic acid, and rosmarinic acid, exerted different immumodulatory activities in vitro. In brief, rosmarinic acid significantly suppressed IL-8 production, while the other two compounds inhibited IL-1β production. Further study is needed to explore the role of bioactive compounds of rosemary in mitigation of P. acnes–induced inflammation. PMID:23514231

  9. Weight Suppression Predicts Time to Remission from Bulimia Nervosa

    ERIC Educational Resources Information Center

    Lowe, Michael R.; Berner, Laura A.; Swanson, Sonja A.; Clark, Vicki L.; Eddy, Kamryn T.; Franko, Debra L.; Shaw, Jena A.; Ross, Stephanie; Herzog, David B.

    2011-01-01

    Objective: To investigate whether, at study entry, (a) weight suppression (WS), the difference between highest past adult weight and current weight, prospectively predicts time to first full remission from bulimia nervosa (BN) over a follow-up period of 8 years, and (b) weight change over time mediates the relationship between WS and time to first…

  10. Codon recognition during frameshift suppression in Saccharomyces cerevisiae.

    PubMed Central

    Gaber, R F; Culbertson, M R

    1984-01-01

    A genetic approach has been used to establish the molecular basis of 4-base codon recognition by frameshift suppressor tRNA containing an extra nucleotide in the anticodon. We have isolated all possible base substitution mutations at the position 4 (N) in the 3'-CCCN-5' anticodon of a Saccharomyces cerevisiae frameshift suppressor glycine tRNA encoded by the SUF16 gene. Base substitutions at +1 frameshift sites in the his4 gene have also been obtained such that all possible 4-base 5'-GGGN-3' codons have been identified. By testing for suppression in different strains that collectively represent all 16 possible combinations of position 4 nucleotides, we show that frameshift suppression does not require position 4 base pairing. Nonetheless, position 4 interactions influence the efficiency of suppression. Our results suggest a model in which 4-base translocation of mRNA on the ribosome is directed primarily by the number of nucleotides in the anticodon loop, whereas the resulting efficiency of suppression is dependent on the nature of position 4 nucleotides. Images PMID:6390183

  11. Stopping Speech Suppresses the Task-Irrelevant Hand

    ERIC Educational Resources Information Center

    Cai, Weidong; Oldenkamp, Caitlin L.; Aron, Adam R.

    2012-01-01

    Some situations require one to quickly stop an initiated response. Recent evidence suggests that rapid stopping engages a mechanism that has diffuse effects on the motor system. For example, stopping the hand dampens the excitability of the task-irrelevant leg. However, it is unclear whether this "global suppression" could apply across wider motor…

  12. Sequential Analysis of the Numerical Stroop Effect Reveals Response Suppression

    ERIC Educational Resources Information Center

    Kadosh, Roi Cohen; Gevers, Wim; Notebaert, Wim

    2011-01-01

    Automatic processing of irrelevant stimulus dimensions has been demonstrated in a variety of tasks. Previous studies have shown that conflict between relevant and irrelevant dimensions can be reduced when a feature of the irrelevant dimension is repeated. The specific level at which the automatic process is suppressed (e.g., perceptual repetition,…

  13. DETAIL VIEW OF THE SOUND SUPPRESSION SPRAY NOZZLE POSITIONED AT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL VIEW OF THE SOUND SUPPRESSION SPRAY NOZZLE POSITIONED AT THE CORNER OF THE PORT SRB EXHAUST OPENING - Cape Canaveral Air Force Station, Launch Complex 39, Mobile Launcher Platforms, Launcher Road, East of Kennedy Parkway North, Cape Canaveral, Brevard County, FL

  14. Rest tremor suppression may separate essential from parkinsonian rest tremor.

    PubMed

    Papengut, Frank; Raethjen, Jan; Binder, Andreas; Deuschl, Günther

    2013-07-01

    Rest tremor at 4-6 Hz is typical for classical rest tremor (PT) of Parkinson's disease (PD). But rest tremor also appears in other tremor syndromes and may therefore cause a misdiagnosis. In this study we evaluated if suppression of tremor during movement onset is a characteristic feature of Parkinsonian Tremor distinguishing PT from Essential tremor (ET) and if this sign can be reliably diagnosed. Clinically diagnosed patients with PT (n = 44) and ET (n = 22) with rest tremor were included. Video sequences were recorded according to a standardized protocol focusing on the change of tremor amplitude during transition from rest to posture (test 1) or to a target-directed movement (test 2). These videos were assessed for rest tremor suppression by 4 reviewers (2 specialists and 2 residents) blinded to the clinical diagnosis and were compared to the personal assessment of an unblinded movement disorder specialist. Rest tremor suppression was found in 39/44 PD patients and in 2/22 patients with ET during the personal assessment. Rest tremor suppression showed a high sensitivity (0.92-1.00) and an acceptable specificity (0.69-0.95) for PD tremor in both tests. The interrater-reliability of the video-sequences was good to very good (κ 0.73-0.91). Less than 3% of the video sequences were misclassified. We conclude that the assessment of the suppression of rest tremor during movement initiation is a simple and reliable tool to separate PT from rest tremor in ET also suggesting that the mechanisms of rest tremor in these two diseases are different.

  15. Serum thyrotropin (TSH) levels in patients with suppressed pituitary function

    SciTech Connect

    Vasavada, P.; Chen, I.; Maxon, H.; Barnes, E.; Sperling, M.

    1984-01-01

    The diagnosis of borderline hyperthyroidism is difficult. A sensitive radioimmunoassay capable of detecting subnormal levels of serum TSH may be of value in confirming this diagnosis because of the suppressed pituitary function in this disease state. This sensitive assay may also be useful in monitoring the suppression of pituitary function in thyroid cancer patients receiving thyroid hormone therapy. A sensitive radioimmunoassay capable of detecting serum TSH levels as low as 0.25 ..mu..U/m1 with coefficients of variation less than 17.2% was used to measure serum TSH levels in 80 healthy subjects, 44 hyperthyroid patients, and 25 athyrotic thyroid cancer patients on daily suppressive doses of thyroxine. All healthy subjects had detectable TSH levels with a mean value of 1.17 and two standard deviation ranges of 0.41 - 2.70 ..mu..U/m1 (lognormal distribution). Although the mean +-1 SEM value of 0.63 +- 0.003 ..mu..Um1 for hyperthyroid patients and 0.76 +- 0.08 ..mu..U/ml for thyroid cancer patients were significantly lower than that of healthy subjects (t-test, p<0.05), subnormal levels of serum TSH were found in only 28.6% (12/42) and 24% (6/25) of hyperthyroid and thyroid cancer patients, respectively. TSH stimulation tests performed in 6 of the cancer patients all gave suppressed responses. Because of considerable overlap, serum TSH levels alone cannot distinguish hyperthyroidsm from euthyroidism. However, a sensitive TSH radioimmunoassay such as the one described here may be of value in evaluating the extent of pituitary suppression in thyroid cancer therapy.

  16. Assessing Suppression in Amblyopic Children With a Dichoptic Eye Chart

    PubMed Central

    Birch, Eileen E.; Morale, Sarah E.; Jost, Reed M.; De La Cruz, Angie; Kelly, Krista R.; Wang, Yi-Zhong; Bex, Peter J.

    2016-01-01

    Purpose Suppression has a key role in the etiology of amblyopia, and contrast-balanced binocular treatment can overcome suppression and improve visual acuity. Quantitative assessment of suppression could have a role in managing amblyopia. We describe a novel eye chart to assess suppression in children. Methods We enrolled 100 children (7–12 years; 63 amblyopic, 25 nonamblyopic with strabismus or anisometropia, 12 controls) in the primary cohort and 22 children (3–6 years; 13 amblyopic, 9 nonamblyopic) in a secondary cohort. Letters were presented on a dichoptic display (5 letters per line). Children wore polarized glasses so that each eye saw a different letter chart. At each position, the identity of the letter and its contrast on each eye's chart differed. Children read 8 lines of letters for each of 3 letter sizes. The contrast balance ratio was the ratio at which 50% of letters seen by the amblyopic eye were reported. Results Amblyopic children had significantly higher contrast balance ratios for all letter sizes compared to nonamblyopic children and controls, requiring 4.6 to 5.6 times more contrast in the amblyopic eye compared to the fellow eye (P < 0.0001). Amblyopic eye visual acuity was correlated with contrast balance ratio (r ranged from 0.49–0.57 for the 3 letter sizes). Change in visual acuity with amblyopia treatment was correlated with change in contrast balance ratio (r ranged from 0.43–0.62 for the 3 letter sizes). Conclusions Severity of suppression can be monitored as part of a routine clinical exam in the management of amblyopia in children. PMID:27784068

  17. Acute seizure suppression by transcranial direct current stimulation in rats

    PubMed Central

    Dhamne, Sameer C; Ekstein, Dana; Zhuo, Zhihong; Gersner, Roman; Zurakowski, David; Loddenkemper, Tobias; Pascual-Leone, Alvaro; Jensen, Frances E; Rotenberg, Alexander

    2015-01-01

    Objective Cathodal transcranial direct current stimulation (tDCS) is a focal neuromodulation technique that suppresses cortical excitability by low-amplitude constant electrical current, and may have an antiepileptic effect. Yet, tDCS has not been tested in status epilepticus (SE). Furthermore, a combined tDCS and pharmacotherapy antiseizure approach is unexplored. We therefore examined in the rat pentylenetetrazol (PTZ) SE model whether cathodal tDCS (1) suppresses seizures, (2) augments lorazepam (LZP) efficacy, and (3) enhances GABAergic cortical inhibition. Methods Experiment 1 aimed to identify an effective cathodal tDCS intensity. Rats received intraperitoneal PTZ followed by tDCS (sham, cathodal 1 mA, or cathodal 0.1 mA; for 20 min), and then a second PTZ challenge. In Experiment 2, two additional animal groups received a subtherapeutic LZP dose after PTZ, and then verum or sham tDCS. Clinical and electroencephalography (EEG) epileptic activity were compared between all groups. In Experiment 3, we measured GABA-mediated paired-pulse inhibition of the motor evoked potential by paired-pulse transcranial magnetic stimulation (ppTMS) in rats that received PTZ or saline, and either verum or sham tDCS. Results Cathodal 1 mA tDCS (1) reduced EEG spike bursts, and suppressed clinical seizures after the second PTZ challenge, (2) in combination with LZP was more effective in seizure suppression and improved the clinical seizure outcomes compared to either tDCS or LZP alone, and (3) prevented the loss of ppTMS motor cortex inhibition that accompanied PTZ injection. Interpretation These results suggest that cathodal 1 mA tDCS alone and in combination with LZP can suppress seizures by augmenting GABAergic cortical inhibition. PMID:26339678

  18. Suppression of Low Strain Rate Nonpremixed Flames by an Agent

    NASA Technical Reports Server (NTRS)

    Hamins, A.; Bundy, M.; Puri, I. K.; McGrattan, K.; Park, W. C.

    2001-01-01

    The agent concentration required to achieve the suppression of low strain rate nonpremixed flames is an important consideration for fire protection in a microgravity environment such as a space platform. Currently, there is a lack of understanding of the structure and extinction of low strain rate (<20 s(exp -1)) nonpremixed flames. The exception to this statement is the study by Maruta et al., who reported measurements of low strain rate suppression of methane-air diffusion flames with N2 added to the fuel stream under microgravity conditions. They found that the nitrogen concentration required to achieve extinction increased as the strain rate decreased until a critical value was obtained. As the strain rate was further decreased, the required N2 concentration decreased. This phenomenon was termed "turning point" behavior and was attributed to radiation-induced nonpremixed flame extinction. In terms of fire safety, a critical agent concentration assuring suppression under all flow conditions represents a fundamental limit for nonpremixed flames. Counterflow flames are a convenient configuration for control of the flame strain rate. In high and moderately strained near-extinction nonpremixed flames, analysis of flame structure typically neglects radiant energy loss because the flames are nonluminous and the hot gas species are confined to a thin reaction zone. In counterflowing CH4-air flames, for example, radiative heat loss fractions ranging from 1 to 6 percent have been predicted and measured. The objective of this study is to investigate the impact of radiative emission, flame strain, agent addition, and buoyancy on the structure and extinction of low strain rate nonpremixed flames through measurements and comparison with flame simulations. The suppression effectiveness of a number of suppressants (N2, CO2, or CF3Br) was considered as they were added to either the fuel or oxidizer streams of low strain rate methane-air diffusion flames.

  19. Specific microbial attachment to root knot nematodes in suppressive soil.

    PubMed

    Adam, Mohamed; Westphal, Andreas; Hallmann, Johannes; Heuer, Holger

    2014-05-01

    Understanding the interactions of plant-parasitic nematodes with antagonistic soil microbes could provide opportunities for novel crop protection strategies. Three arable soils were investigated for their suppressiveness against the root knot nematode Meloidogyne hapla. For all three soils, M. hapla developed significantly fewer galls, egg masses, and eggs on tomato plants in unsterilized than in sterilized infested soil. Egg numbers were reduced by up to 93%. This suggested suppression by soil microbial communities. The soils significantly differed in the composition of microbial communities and in the suppressiveness to M. hapla. To identify microorganisms interacting with M. hapla in soil, second-stage juveniles (J2) baited in the test soil were cultivation independently analyzed for attached microbes. PCR-denaturing gradient gel electrophoresis of fungal ITS or 16S rRNA genes of bacteria and bacterial groups from nematode and soil samples was performed, and DNA sequences from J2-associated bands were determined. The fingerprints showed many species that were abundant on J2 but not in the surrounding soil, especially in fungal profiles. Fungi associated with J2 from all three soils were related to the genera Davidiella and Rhizophydium, while the genera Eurotium, Ganoderma, and Cylindrocarpon were specific for the most suppressive soil. Among the 20 highly abundant operational taxonomic units of bacteria specific for J2 in suppressive soil, six were closely related to infectious species such as Shigella spp., whereas the most abundant were Malikia spinosa and Rothia amarae, as determined by 16S rRNA amplicon pyrosequencing. In conclusion, a diverse microflora specifically adhered to J2 of M. hapla in soil and presumably affected female fecundity.

  20. Materials Science Research Rack-1 Fire Suppressant Distribution Test Report

    NASA Technical Reports Server (NTRS)

    Wieland, P. O.

    2002-01-01

    Fire suppressant distribution testing was performed on the Materials Science Research Rack-1 (MSRR-1), a furnace facility payload that will be installed in the U.S. Lab module of the International Space Station. Unlike racks that were tested previously, the MSRR-1 uses the Active Rack Isolation System (ARIS) to reduce vibration on experiments, so the effects of ARIS on fire suppressant distribution were unknown. Two tests were performed to map the distribution of CO2 fire suppressant throughout a mockup of the MSRR-1 designed to have the same component volumes and flowpath restrictions as the flight rack. For the first test, the average maximum CO2 concentration for the rack was 60 percent, achieved within 45 s of discharge initiation, meeting the requirement to reach 50 percent throughout the rack within 1 min. For the second test, one of the experiment mockups was removed to provide a worst-case configuration, and the average maximum CO2 concentration for the rack was 58 percent. Comparing the results of this testing with results from previous testing leads to several general conclusions that can be used to evaluate future racks. The MSRR-1 will meet the requirements for fire suppressant distribution. Primary factors that affect the ability to meet the CO2 distribution requirements are the free air volume in the rack and the total area and distribution of openings in the rack shell. The length of the suppressant flowpath and degree of tortuousness has little correlation with CO2 concentration. The total area of holes in the rack shell could be significantly increased. The free air volume could be significantly increased. To ensure the highest maximum CO2 concentration, the PFE nozzle should be inserted to the stop on the nozzle.

  1. Low Dose Suppression of Neoplastic Transformation in Vitro

    SciTech Connect

    John Leslie Redpath

    2012-05-01

    This grant was to study the low dose suppression of neoplastic transformation in vitro and the shape of the dose-response curve at low doses and dose-rates of ionizing radiation. Previous findings had indicated a suppression of transformation at dose <10cGy of low-LET radiation when delivered at high dose-rate. The present study indicates that such suppression extends out to doses in excess of 100cGy when the dose (from I-125 photons) is delivered at dose-rates as low as 0.2 mGy/min and out to in excess of {approx}25cGy the highest dose studied at the very low dose-rate of 0.5 mGy/day. We also examined dose-rate effects for high energy protons (which are a low-LET radiation) and suppression was evident below {approx}10cGy for high dose-rate delivery and at least out to 50cGy for low dose-rate (20cGy/h) delivery. Finally, we also examined the effect of low doses of 1 GeV/n iron ions (a high-LET radiation) delivered at high dose-rate on transformation at low doses and found a suppression below {approx}10cGy that could be attributable to an adaptive response in bystander cells induced by the associated low-LET delta rays. These results have implications for cancer risk assessment at low doses.

  2. Mode of ATM-dependent suppression of chromosome translocation.

    PubMed

    Yamauchi, Motohiro; Suzuki, Keiji; Oka, Yasuyoshi; Suzuki, Masatoshi; Kondo, Hisayoshi; Yamashita, Shunichi

    2011-12-09

    It is well documented that deficiency in ataxia telangiectasia mutated (ATM) protein leads to elevated frequency of chromosome translocation, however, it remains poorly understood how ATM suppresses translocation frequency. In the present study, we addressed the mechanism of ATM-dependent suppression of translocation frequency. To know frequency of translocation events in a whole genome at once, we performed centromere/telomere FISH and scored dicentric chromosomes, because dicentric and translocation occur with equal frequency and by identical mechanism. By centromere/telomere FISH analysis, we confirmed that chemical inhibition or RNAi-mediated knockdown of ATM causes 2 to 2.5-fold increase in dicentric frequency at first mitosis after 2 Gy of gamma-irradiation in G0/G1. The FISH analysis revealed that ATM/p53-dependent G1 checkpoint suppresses dicentric frequency, since RNAi-mediated knockdown of p53 elevated dicentric frequency by 1.5-fold. We found ATM also suppresses dicentric occurrence independently of its checkpoint role, as ATM inhibitor showed additional effect on dicentric frequency in the context of p53 depletion and Chk1/2 inactivation. Epistasis analysis using chemical inhibitors revealed that ATM kinase functions in the same pathway that requires kinase activity of DNA-dependent protein kinase catalytic subunit (DNA-PKcs) to suppress dicentric frequency. From the results in the present study, we conclude that ATM minimizes translocation frequency through its commitment to G1 checkpoint and DNA double-strand break repair pathway that requires kinase activity of DNA-PKcs.

  3. Immunologic Suppression To Peanut During Immunotherapy Is Often Transient

    PubMed Central

    Gorelik, M.; Narisety, S.D.; Guerrerio, A.L.; Chichester, K.; Keet, C.A.; Bieneman, A.P.; Hamilton, R. G.; Wood, R.A; Schroeder, J.T.; Frischmeyer-Guerrerio, P.A.

    2014-01-01

    Background Studies suggest that oral (OIT) and sublingual (SLIT) immunotherapy for food allergy hold promise; however, the immunologic mechanisms underlying these therapies are not well understood. Objective To generate insights into the mechanisms and duration of immunologic suppression to peanut during immunotherapy (IT). Methods Blood was obtained from subjects at baseline and at multiple timepoints during a placebo-controlled trial of peanut OIT and SLIT. Immunologic outcomes included spontaneous and stimulated basophil activity by automated fluorometry (histamine) and flow cytometry (activation markers, IL-4), allergen-induced cytokine expression in dendritic cell (DC)-T cell co-cultures by multiplexing technology, and expression of MHC II and costimulatory molecules on DCs by flow cytometry. Results Spontaneous and allergen-induced basophil reactivity (histamine release, CD63 expression, and IL-4 production) were suppressed during dose escalation and after 6 months of maintenance dosing. Peanut- and dust mite-induced expression of TH2 cytokines was reduced in DC-T cell co-cultures during IT. This was associated with decreased levels of CD40, HLA-DR, and CD86 expression on DCs, and increased expression of CD80. These effects were most striking in myeloid DC-T cell co-cultures from subjects receiving OIT. Many markers of immunologic suppression reversed following withdrawal from IT, and in some cases during ongoing maintenance therapy. Conclusion OIT and SLIT for peanut allergy induce rapid suppression of basophil effector functions, dendritic cell activation, and Th2 cytokine responses during the initial phases of IT in an antigen non-specific manner. While there was some inter-individual variation, in many patients, suppression appeared to be temporary. PMID:25542883

  4. PRAXIS: low thermal emission high efficiency OH suppressed fibre spectrograph

    NASA Astrophysics Data System (ADS)

    Content, Robert; Bland-Hawthorn, Joss; Ellis, Simon; Gers, Luke; Haynes, Roger; Horton, Anthony; Lawrence, Jon; Leon-Saval, Sergio; Lindley, Emma; Min, Seong-Sik; Shortridge, Keith; Staszak, Nick; Trinh, Christopher; Xavier, Pascal; Zhelem, Ross

    2014-07-01

    PRAXIS is a second generation instrument that follows on from GNOSIS, which was the first instrument using fibre Bragg gratings for OH suppression to be deployed on a telescope. The Bragg gratings reflect the NIR OH lines while being transparent to the light between the lines. This gives in principle a much higher signal-noise ratio at low resolution spectroscopy but also at higher resolutions by removing the scattered wings of the OH lines. The specifications call for high throughput and very low thermal and detector noise so that PRAXIS will remain sky noise limited even with the low sky background levels remaining after OH suppression. The optical and mechanical designs are presented. The optical train starts with fore-optics that image the telescope focal plane on an IFU which has 19 hexagonal microlenses each feeding a multi-mode fibre. Seven of these fibres are attached to a fibre Bragg grating OH suppression system while the others are reference/acquisition fibres. The light from each of the seven OH suppression fibres is then split by a photonic lantern into many single mode fibres where the Bragg gratings are imprinted. Another lantern recombines the light from the single mode fibres into a multi-mode fibre. A trade-off was made in the design of the IFU between field of view and transmission to maximize the signal-noise ratio for observations of faint, compact objects under typical seeing. GNOSIS used the pre-existing IRIS2 spectrograph while PRAXIS will use a new spectrograph specifically designed for the fibre Bragg grating OH suppression and optimised for 1.47 μm to 1.7 μm (it can also be used in the 1.09 μm to 1.26 μm band by changing the grating and refocussing). This results in a significantly higher transmission due to high efficiency coatings, a VPH grating at low incident angle and optimized for our small bandwidth, and low absorption glasses. The detector noise will also be lower thanks to the use of a current generation HAWAII-2RG detector

  5. Dopamine agonist suppression of rapid-eye-movement sleep is secondary to sleep suppression mediated via limbic structures

    SciTech Connect

    Miletich, R.S.

    1985-01-01

    The effects of pergolide, a direct dopamine receptor agonist, on sleep and wakefulness, motor behavior and /sup 3/H-spiperone specific binding in limbic structures and striatum in rats was studied. The results show that pergolide induced a biphasic dose effect, with high doses increasing wakefulness and suppressing sleep while low dose decreased wakefulness, but increased sleep. It was shown that pergolide-induced sleep suppression was blocked by ..cap alpha..-glupenthixol and pimozide, two dopamine receptor antagonists. It was further shown that pergolide merely delayed the rebound resulting from rapid-eye-movement (REM) sleep deprivation, that dopamine receptors stimulation had no direct effect on the period, phase or amplitude of the circadian rhythm of REM sleep propensity and that there was no alteration in the coupling of REM sleep episodes with S/sub 2/ episodes. Rapid-eye-movement sleep deprivation resulted in increased sensitivity to the pergolide-induced wakefulness stimulation and sleep suppression and pergolide-induced motor behaviors of locomotion and head bobbing. /sup 3/H-spiperone specific binding to dopamine receptors was shown to be altered by REM sleep deprivation in the subcortical limbic structures. It is concluded that the REM sleep suppressing action of dopamine receptor stimulation is secondary to sleep suppression per se and not secondary to a unique effect on the REM sleep. Further, it is suggested that the wakefulness stimulating action of dopamine receptor agonists is mediated by activation of the dopamine receptors in the terminal areas of the mesolimbocortical dopamine projection system.

  6. Durability, negative impact, and neuropsychological predictors of tic suppression in children with chronic tic disorder.

    PubMed

    Woods, Douglas W; Himle, Michael B; Miltenberger, Raymond G; Carr, James E; Osmon, David C; Karsten, Amanda M; Jostad, Candice; Bosch, Amanda

    2008-02-01

    Chronic tic disorders are characterized by involuntary motor and vocal tics, which are influenced by contextual factors. Recent research has shown that (a) children can suppress tics for brief periods of time, (b) suppression is enhanced when programmed reinforcement is provided for tic-free intervals, and (c) short periods of suppression do not result in a paradoxical "rebound" in tic frequency when active suppression has ceased. The current study extended existing research in three important ways. First, we examined whether tic suppression ability decreased as suppression duration increased from 5 to 25 to 40 min. Second, we examined post-suppression tic frequency to test whether longer periods of suppression were more likely to be associated with a rebound effect. Finally, we explored neuropsychological predictors of tic suppression. Thirteen children with Tourette syndrome or a chronic tic disorder completed the study. Results showed that (a) tic suppression was sustained for all of the suppression durations, (b) rebound effects were not observed following any of the suppression durations, and (c) ability to suppress was correlated with omission, but not commission errors on a continuous performance task. Implications of these findings are discussed.

  7. The effect of essential oil formulations for potato sprout suppression.

    PubMed

    Owolabi, Moses S; Lajide, Labunmi; Oladimeji, Matthew O; Setzer, William N

    2010-04-01

    The concerns over safety and environmental impact of synthetic pesticides such as chlorpropham (CIPC) has stimulated interest in finding environmentally benign, natural sprout suppressants, including essential oils. The effects of Chenopodium ambrosioides and Lippia multiflora essential oils on sprout growth and decay of stored potatoes has been investigated. Formulations of essential oils with alumina, bentonite, or kaolin, both with and without Triton X-100 additive, were tested. These formulations have been compared to the pulverized plant materials themselves as well as wick-volatilized essential oils. The results showed that the tested oils possess compositions that make them suitable for application as sprout suppressants. Additionally, the formulation seems to be able to reduce the volatility of the essential oil and artificially extend dormancy of stored potatoes.

  8. Methylglyoxal: possible link between hyperglycaemia and immune suppression?

    PubMed

    Price, Claire L; Knight, Stella C

    2009-09-01

    No matter the cause of diabetes, the result is always hyperglycaemia. This excess glucose metabolism drives several damage pathways and raises concentrations of the reactive dicarbonyl, methylglyoxal (MG). MG can modify the structure and function of target molecules by forming advanced glycation end-products (AGEs) that act through their receptor (RAGE) to perpetuate vascular and neuronal injury responsible for long-term complications of diabetes. Diabetes patients also suffer lower resistance to many common infections, although the cause(s) for this lower resistance remains elusive. Here, we review recent evidence concerning immune suppression in diabetes and discuss the effects of MG on components of the immune system. We suggest that MG could be a missing link between hyperglycaemia and immune suppression in diabetes.

  9. Suppression of respiratory motion artifacts in magnetic resonance imaging.

    PubMed

    Wood, M L; Henkelman, R M

    1986-01-01

    Anatomical structures that are displaced periodically during respiration are repeated as ghosts in magnetic resonance (MR) images. These ghosts can be suppressed in many ways: the averaging of multiple sets of data, respiratory gating, deliberate positioning of ghosts, and respiratory ordering of phase encoding. Each method has a unique mechanism, which is described in detail. A theoretical investigation has been conducted into the effects that the methods have on the point spread function of a moving point. Data acquired in Fourier imaging are actually in the spatial frequency domain, so that respiratory motion can be regarded as a function of spatial frequency. The four methods above modify this functional dependence in different ways, allowing a unified comparison. Motion artifact suppression imposes additional constraints on image acquisition, which can prolong the imaging time. A technique has been developed that keeps the imaging time short by using the configuration of the subject to regulate the timing of image acquisition.

  10. Suppression bias at the Journal of Occupational and Environmental Medicine.

    PubMed

    Egilman, David S

    2005-01-01

    When the Journal of Occupational and Environmental Medicine rejected an article on corporate suppression of science on the grounds that the topic "was not a high priority" for journal readers, the author bought advertising space in JOEM to present his findings. The JOEM editor regretted he had not seen the ad to prevent its publication, and subsequently allowed the corporate-sponsored authors of a criticized study to respond to the advertisement. The editor then refused to allow the ad's author to respond in turn, suppressing scientific information with the apparent intent of protecting the interests and profits of the corporate sponsor. A reputable journal has a responsibility to eschew corporate interests and work to uncover science hidden by interests that do not prioritize the pursuit of truth. JOEM needs to re-examine its priorities.

  11. Suppression of phonon transport in molecular Christmas trees.

    PubMed

    Lambert, Colin John; Famili, Marjan; Grace, Iain; Sadeghi, Hatef

    2017-02-27

    Minimising the phonon thermal conductance of self-assembled molecular films, whilst preserving their electrical properties, is highly desirable, both for thermal management at the nanoscale and for the design of high-efficiency thermoelectric materials. Here we highlight a new strategy for minimising the phonon thermal conductance of Christmas-tree-like molecules composed of a long trunk, along which phonons can propagate, attached to pendant molecular branches. We demonstrate that phonon transport along the trunk is suppressed by Fano resonances associated with internal vibrational modes of the branches and that thermal conductance is suppressed most-effectively in molecules with pendant branches of different lengths. As examples, we use density functional theory to demonstrate the reduction in phonon transport in tree-like molecules formed from alkane or acene trunks with various pendant branches.

  12. Amplitude suppression and chaos control in epileptic EEG signals.

    PubMed

    Majumdar, Kaushik; Myers, Mark H

    2006-03-01

    In this paper we have proposed a novel amplitude suppression algorithm for EEG signals collected during epileptic seizure. Then we have proposed a measure of chaoticity for a chaotic signal, which is somewhat similar to measuring sensitive dependence on initial conditions by measuring Lyapunov exponent in a chaotic dynamical system. We have shown that with respect to this measure the amplitude suppression algorithm reduces chaoticity in a chaotic signal (EEG signal is chaotic). We have compared our measure with the estimated largest Lyapunov exponent measure by the largelyap function, which is similar to Wolf's algorithm. They fit closely for all but one of the cases. How the algorithm can help to improve patient specific dosage titration during vagus nerve stimulation therapy has been outlined.

  13. Thioredoxin reductase 1 suppresses adipocyte differentiation and insulin responsiveness

    PubMed Central

    Peng, Xiaoxiao; Giménez-Cassina, Alfredo; Petrus, Paul; Conrad, Marcus; Rydén, Mikael; Arnér, Elias S. J.

    2016-01-01

    Recently thioredoxin reductase 1 (TrxR1), encoded by Txnrd1, was suggested to modulate glucose and lipid metabolism in mice. Here we discovered that TrxR1 suppresses insulin responsiveness, anabolic metabolism and adipocyte differentiation. Immortalized mouse embryonic fibroblasts (MEFs) lacking Txnrd1 (Txnrd1−/−) displayed increased metabolic flux, glycogen storage, lipogenesis and adipogenesis. This phenotype coincided with upregulated PPARγ expression, promotion of mitotic clonal expansion and downregulation of p27 and p53. Enhanced Akt activation also contributed to augmented adipogenesis and insulin sensitivity. Knockdown of TXNRD1 transcripts accelerated adipocyte differentiation also in human primary preadipocytes. Furthermore, TXNRD1 transcript levels in subcutaneous adipose tissue from 56 women were inversely associated with insulin sensitivity in vivo and lipogenesis in their isolated adipocytes. These results suggest that TrxR1 suppresses anabolic metabolism and adipogenesis by inhibition of intracellular signaling pathways downstream of insulin stimulation. PMID:27346647

  14. A saponin-detoxifying enzyme mediates suppression of plant defences

    NASA Astrophysics Data System (ADS)

    Bouarab, K.; Melton, R.; Peart, J.; Baulcombe, D.; Osbourn, A.

    2002-08-01

    Plant disease resistance can be conferred by constitutive features such as structural barriers or preformed antimicrobial secondary metabolites. Additional defence mechanisms are activated in response to pathogen attack and include localized cell death (the hypersensitive response). Pathogens use different strategies to counter constitutive and induced plant defences, including degradation of preformed antimicrobial compounds and the production of molecules that suppress induced plant defences. Here we present evidence for a two-component process in which a fungal pathogen subverts the preformed antimicrobial compounds of its host and uses them to interfere with induced defence responses. Antimicrobial saponins are first hydrolysed by a fungal saponin-detoxifying enzyme. The degradation product of this hydrolysis then suppresses induced defence responses by interfering with fundamental signal transduction processes leading to disease resistance.

  15. Robust mainlobe interference suppression for coherent interference environment

    NASA Astrophysics Data System (ADS)

    Wang, Yasen; Bao, Qinglong; Chen, Zengping

    2016-12-01

    A mainlobe interference suppression method is proposed in this paper, which can still work when the signal of interest (SOI) is present in the training data. In this method, the iterative adaptive approach (IAA) is applied to spatial spectrum estimation at first. Then, IAA spatial spectrum is used to reconstruct the interference-plus-noise covariance matrix (INCM). Next, the eigenvector associated with mainlobe interference in INCM is determined, and the eigen-projection matrix can be calculated to suppress the mainlobe interference. Meanwhile, the sidelobe-interference-plus-noise covariance matrix (SINCM) can be reconstructed. Finally, the adaptive weight vector is obtained. One main advantage is that the proposed method can deal with coherent mainlobe interference and sidelobe interferences simultaneously. Simulation results demonstrate the effectiveness and robustness of the proposed method.

  16. Navier-Stokes computations of cavity aeroacoustics with suppression devices

    NASA Technical Reports Server (NTRS)

    Baysal, Oktay; Yen, Guan-Wei; Fouladi, Kamran

    1992-01-01

    Effectiveness of two devices to suppress the cavity acoustics was computationally investigated. Two dimensional, computational simulations were performed for the transonic, turbulent flows past a cavity, which was first equipped with a rear face ramp and then with a spoiler. The Reynolds-averaged, unsteady, compressible, full Navier-Stokes equations were solved time accurately by a second-order accurate, implicit, upwind, finite-volume method. The effect of turbulence was included through a Baldwin-Lomax model with modifications for the multiple-wall effects and for the highly vortical flow with a shear layer. The results included instantaneous and time-averaged flow properties, and time-series analyses of the pressure inside the cavity, which compared favorably with the available experimental data. These results were also contrasted with the computed aeroacoustics of the same cavity (length-to-depth ratio of 4.5), but without a device, to demonstrate the suppression effectiveness.

  17. Kalman filtering to suppress spurious signals in adaptive optics control.

    PubMed

    Poyneer, Lisa A; Véran, Jean-Pierre

    2010-11-01

    In many scenarios, an adaptive optics (AO) control system operates in the presence of temporally non-white noise. We use a Kalman filter with a state space formulation that allows suppression of this colored noise, hence improving residual error over the case where the noise is assumed to be white. We demonstrate the effectiveness of this new filter in the case of the estimated Gemini Planet Imager tip-tilt environment, where there are both common-path and non-common-path vibrations. We discuss how this same framework can also be used to suppress spatial aliasing during predictive wavefront control assuming frozen flow in a low-order AO system without a spatially filtered wavefront sensor, and present experimental measurements from Altair that clearly reveal these aliased components.

  18. Hypothesis: smoking decreases breast feeding duration by suppressing prolactin secretion.

    PubMed

    Bahadori, Babak; Riediger, Natalie D; Farrell, Sharla M; Uitz, Elisabeth; Moghadasian, Mohammed F

    2013-10-01

    A number of studies, including new data summarized here, conclude that breast feeding duration is lower in smoking mothers. Although some have suggested that this merely reflects poor health motivation in those prone to smoke, several lines of evidence support the view that chronic smoking does indeed compromise breast feeding by suppressing prolactin secretion and thereby lowering breast milk volume. Moreover, a recent clinical trial shows that an effective smoking cessation program can boost breast feeding duration in smokers. An analysis of pertinent rodents studies suggests that chronic nicotine administration boosts dopaminergic activity in the tuberoinfundibular tract which functions to inhibit prolactin release; this increase in dopaminergic activity, in turn, may reflect a nicotine-mediated suppression of hypothalamic opioid activity.

  19. Thermospermine suppresses auxin-inducible xylem differentiation in Arabidopsis thaliana.

    PubMed

    Yoshimoto, Kaori; Noutoshi, Yoshiteru; Hayashi, Ken-ichiro; Shirasu, Ken; Takahashi, Taku; Motose, Hiroyasu

    2012-08-01

    Thermospermine, a structural isomer of spermine, is synthesized by a thermospermine synthase designated ACAULIS5 (ACL5). Thermospermine-deficient acl5 mutant of Arabidopsis thaliana shows severe dwarfism and excessive xylem differentiation. By screening for compounds that affect xylem differentiation in the acl5 mutant, we identified auxin analogs that remarkably enhanced xylem vessel differentiation in the acl5 mutant but not in the wild type. The xylem-inducing effect of auxin analogs was clearly suppressed by thermospermine, indicating that auxin-inducible xylem differentiation is normally limited by thermospermine. Here, we further characterized xylem-inducing effect of auxin analogs in various organs. Auxin analogs promoted protoxylem differentiation in roots and cotyledons in the acl5 mutant. Our results indicate that the opposite action between thermospermine and auxin in xylem differentiation is common in different organs and also suggest that thermospermine might be required for the suppression of protoxylem differentiation.

  20. Kalman filtering to suppress spurious signals in Adaptive Optics control

    SciTech Connect

    Poyneer, L; Veran, J P

    2010-03-29

    In many scenarios, an Adaptive Optics (AO) control system operates in the presence of temporally non-white noise. We use a Kalman filter with a state space formulation that allows suppression of this colored noise, hence improving residual error over the case where the noise is assumed to be white. We demonstrate the effectiveness of this new filter in the case of the estimated Gemini Planet Imager tip-tilt environment, where there are both common-path and non-common path vibrations. We discuss how this same framework can also be used to suppress spatial aliasing during predictive wavefront control assuming frozen flow in a low-order AO system without a spatially filtered wavefront sensor, and present experimental measurements from Altair that clearly reveal these aliased components.

  1. Method of Suppressing Sublimation in Advanced Thermoelectric Devices

    NASA Technical Reports Server (NTRS)

    Sakamoto, Jeffrey S. (Inventor); Caillat, Thierry (Inventor); Fleurial, Jean-Pierre (Inventor); Snyder, G. Jeffrey (Inventor)

    2009-01-01

    A method of applying a physical barrier to suppress thermal decomposition near a surface of a thermoelectric material including applying a continuous metal foil to a predetermined portion of the surface of the thermoelectric material, physically binding the continuous metal foil to the surface of the thermoelectric material using a binding member, and heating in a predetermined atmosphere the applied and physically bound continuous metal foil and the thermoelectric material to a sufficient temperature in order to promote bonding between the continuous metal foil and the surface of the thermoelectric material. The continuous metal foil forms a physical barrier to enclose a predetermined portion of the surface. Thermal decomposition is suppressed at the surface of the thermoelectric material enclosed by the physical barrier when the thermoelectric element is in operation.

  2. Nucleosomes suppress spontaneous mutations base-specifically in eukaryotes.

    PubMed

    Chen, Xiaoshu; Chen, Zhidong; Chen, Han; Su, Zhijian; Yang, Jianfeng; Lin, Fangqin; Shi, Suhua; He, Xionglei

    2012-03-09

    It is unknown how the composition and structure of DNA within the cell affect spontaneous mutations. Theory suggests that in eukaryotic genomes, nucleosomal DNA undergoes fewer C→T mutations because of suppressed cytosine hydrolytic deamination relative to nucleosome-depleted DNA. Comparative genomic analyses and a mutation accumulation experiment showed that nucleosome occupancy nearly eliminated cytosine deamination, resulting in an ~50% decrease of the C→T mutation rate in nucleosomal DNA. Furthermore, the rates of G→T and A→T mutations were also about twofold suppressed by nucleosomes. On the basis of these results, we conclude that nucleosome-dependent mutation spectra affect eukaryotic genome structure and evolution and may have implications for understanding the origin of mutations in cancers and in induced pluripotent stem cells.

  3. Emergence and accumulation of novel pathogens suppress an invasive species.

    PubMed

    Stricker, Kerry Bohl; Harmon, Philip F; Goss, Erica M; Clay, Keith; Luke Flory, S

    2016-04-01

    Emerging pathogens are a growing threat to human health, agriculture and the diversity of ecological communities but may also help control problematic species. Here we investigated the diversity, distribution and consequences of emerging fungal pathogens infecting an aggressive invasive grass that is rapidly colonising habitats throughout the eastern USA. We document the recent emergence and accumulation over time of diverse pathogens that are members of a single fungal genus and represent multiple, recently described or undescribed species. We also show that experimental suppression of these pathogens increased host performance in the field, demonstrating the negative effects of emerging pathogens on invasive plants. Our results suggest that invasive species can facilitate pathogen emergence and amplification, raising concerns about movement of pathogens among agricultural, horticultural, and wild grasses. However, one possible benefit of pathogen accumulation is suppression of aggressive invaders over the long term, potentially abating their negative impacts on native communities.

  4. Harms caused by China's 1906-17 opium suppression intervention.

    PubMed

    Windle, James

    2013-09-01

    Between 1906 and 1917 China (under the Imperial and then Republican regimes) enacted a highly effective intervention to suppress the production of opium. Evidence from British Foreign Office records suggest that the intervention was centred, in many areas, upon a highly repressive incarnation of law enforcement in which rural populations had their property destroyed, their land confiscated and/or were publically tortured, humiliated and executed. Crops were forcefully eradicated and resistance was often brutally suppressed by the military. As few farmers received compensation or support for alternative livelihood creation the intervention pushed many deeper into poverty. Importantly, the repressive nature of the opium ban appears to have been a contributing factor to the fragmentation of China, highlighting the counter-productivity of repressive interventions to reduce drug crop production.

  5. Laser pumped (4)He magnetometer with light shift suppression.

    PubMed

    Lin, Zaisheng; Wang, He; Peng, Xiang; Wu, Teng; Guo, Hong

    2016-11-01

    We report a laser-pumped (4)He atomic magnetometer with light shift suppression through the atomic sensor itself. A linearly polarized light is used to optically align the (4)He metastable atoms and we monitor the magneto-optical double resonance (MODR) signals produced by the left- and right-circularly orthogonal components. It is shown that light shift leads to the atomic alignment to orientation conversion effect, and thus, the difference between the two MODR signals. One of these two MODR signals is locked at the Larmor frequency and is used to measure the ambient magnetic field, while the differential signal is, simultaneously, fed back to suppress the light shift. The scheme could be of the advantage to the design of compact magnetometers by reducing the systematic errors due to light shift.

  6. ATM promotes apoptosis and suppresses tumorigenesis in response to Myc

    NASA Astrophysics Data System (ADS)

    Pusapati, Raju V.; Rounbehler, Robert J.; Hong, Sungki; Powers, John T.; Yan, Mingshan; Kiguchi, Kaoru; McArthur, Mark J.; Wong, Paul K.; Johnson, David G.

    2006-01-01

    Overexpression of the c-myc oncogene contributes to the development of a significant number of human cancers. In response to deregulated Myc activity, the p53 tumor suppressor is activated to promote apoptosis and inhibit tumor formation. Here we demonstrate that p53 induction in response to Myc overexpression requires the ataxia-telangiectasia mutated (ATM) kinase, a major regulator of the cellular response to DNA double-strand breaks. In a transgenic mouse model overexpressing Myc in squamous epithelial tissues, inactivation of Atm suppresses apoptosis and accelerates tumorigenesis. Deregulated Myc expression induces DNA damage in primary transgenic keratinocytes and the formation of H2AX and phospho-SMC1 foci in transgenic tissue. These findings suggest that Myc overexpression causes DNA damage in vivo and that the ATM-dependent response to this damage is critical for p53 activation, apoptosis, and the suppression of tumor development. p53 | DNA damage

  7. Proton MRS and MRSI of the brain without water suppression.

    PubMed

    Dong, Zhengchao

    2015-04-01

    Water suppression (WS) techniques have played a vital role in the commencement and development of in vivo proton magnetic resonance spectroscopy (MRS, including spectroscopic imaging - MRSI). WS not only made in vivo proton MRS functionally available but also made its applications conveniently accessible, and it has become an indispensable tool in most of the routine applications of in vivo proton MR spectroscopy. On the other hand, WS brought forth some challenges. Therefore, various techniques of proton MRS without WS have been developed since the pioneering work in the late 1990s. After more than one and a half decades of advances in both hardware and software, non-water-suppressed proton MRS is coming to the stage of maturity and seeing increasing application in biomedical research and clinical diagnosis. In this article, we will review progress in the technical development and applications of proton MRS without WS.

  8. Quercetin suppresses lung cancer growth by targeting Aurora B kinase.

    PubMed

    Xingyu, Zhu; Peijie, Ma; Dan, Peng; Youg, Wang; Daojun, Wang; Xinzheng, Chen; Xijun, Zhang; Yangrong, Song

    2016-11-01

    aurora B kinase is highly expressed in several cancer cells and promotes tumorigenesis and progression, and therefore, it is an important target for drug to treat tumors. Quercetin was identified to be an antitumor agent. Herein, we report for the first time that quercetin inhibited aurora B activities by directly binding with aurora B in vitro and in vivo. Ex vivo studies showed that quercetin inhibited aurora B activities in JB6 Cl41 cells and A549 lung cancer cells. Moreover, knockdown of aurora B in A549 cells decreased their sensitivities to quercetin. In vivo study demonstrated that injection of quercetin in A549 tumor-bearing mice effectively suppressed cancer growth. The phosphorylation of histone 3 in tumor tissues was also decreased after quercetin treatment. In short, quercetin can suppress growth of lung cancer cells as an aurora B inhibitor both in vitro and in vivo.

  9. The calpain-suppressing effects of olesoxime in Huntington's disease.

    PubMed

    Weber, Jonasz J; Ortiz Rios, Midea M; Riess, Olaf; Clemens, Laura E; Nguyen, Huu P

    2016-01-01

    Olesoxime, a small molecule drug candidate, has recently attracted attention due to its significant beneficial effects in models of several neurodegenerative disorders including Huntington's disease. Olesoxime's neuroprotective effects have been assumed to be conveyed through a direct, positive influence on mitochondrial function. In a long-term treatment study in BACHD rats, the latest rat model of Huntington's disease, olesoxime revealed a positive influence on mitochondrial function and improved specific behavioral and neuropathological phenotypes. Moreover, a novel target of the compound was discovered, as olesoxime was found to suppress the activation of the calpain proteolytic system, a major contributor to the cleavage of the disease-causing mutant huntingtin protein into toxic fragments, and key player in degenerative processes in general. Results from a second model of Huntington's disease, the Hdh (Q111) knock-in mouse, confirm olesoxime's calpain-suppressing effects and support the therapeutic value of olesoxime for Huntington's disease and other disorders involving calpain overactivation.

  10. Suppressing the numerical Cherenkov radiation in the Yee numerical scheme

    SciTech Connect

    Nuter, Rachel Tikhonchuk, Vladimir

    2016-01-15

    The next generation of laser facilities will routinely produce relativistic particle beams from the interaction of intense laser pulses with solids and/or gases. Their modeling with Particle-In-Cell (PIC) codes needs dispersion-free Maxwell solvers in order to properly describe the interaction of electromagnetic waves with relativistic particles. A particular attention is devoted to the suppression of the numerical Cherenkov instability, responsible for the noise generation. It occurs when the electromagnetic wave is artificially slowed down because of the finite mesh size, thus allowing for the high energy particles to propagate with super-luminous velocities. In the present paper, we show how a slight increase of the light velocity in the Maxwell's equations enables to suppress this instability while keeping a good overall precision of calculations.

  11. Suppression of radiation damping for high precision quantitative NMR.

    PubMed

    Bayle, Kevin; Julien, Maxime; Remaud, Gérald S; Akoka, Serge

    2015-10-01

    True quantitative analysis of concentrated samples by (1)H NMR is made very difficult by Radiation Damping. A novel NMR sequence (inspired by the WET NMR sequence and by Outer Volume Saturation methods) is therefore proposed to suppress this phenomenon by reducing the spatial area and consequently the number of spins contributing to the signal detected. The size of the detected volume can be easily chosen in a large range and line shape distortions are avoided thanks to a uniform signal suppression of the outer volume. Composition of a mixture can as a result be determined with very high accuracy (precision and trueness) at the per mille level whatever the concentrations and without hardware modification.

  12. My Cousin, My Enemy: quasispecies suppression of drug resistance

    PubMed Central

    Kirkegaard, Karla; van Buuren, Nicholas J; Mateo, Roberto

    2017-01-01

    If a freshly minted genome contains a mutation that confers drug resistance, will it be selected in the presence of the drug? Not necessarily. During viral infections, newly synthesized viral genomes occupy the same cells as parent and other progeny genomes. If the antiviral target is chosen so that the drug-resistant progeny’s growth is dominantly inhibited by the drug-susceptible members of its intracellular family, its outgrowth can be suppressed. Precedent for ‘dominant drug targeting’ as a deliberate approach to suppress the outgrowth of inhibitor-resistant viruses has been established for envelope variants of vesicular stomatitis virus and for capsid variants of poliovirus and dengue virus. Small molecules that stabilize oligomeric assemblages are a promising means to an unfit family to destroy the effectiveness of a newborn drug-resistant relative due to the co-assembly of drug-susceptible and drug-resistant monomers. PMID:27764731

  13. Endotoxin suppresses surfactant synthesis in cultured rat lung cells

    SciTech Connect

    Li, J.J.; Sanders, R.L.; McAdam, K.P.; Gelfand, J.A.; Burke, J.F.

    1989-02-01

    Pulmonary complications secondary to postburn sepsis are a major cause of death in burned patients. Using an in vitro organotypic culture system, we examined the effect of E. coli endotoxin (LPS) on lung cell surfactant synthesis. Our results showed that E. coli endotoxin (1.0, 2.5, 10 micrograms LPS/ml) was capable of suppressing the incorporation of /sup 3/H-choline into de novo synthesized surfactant, lamellar bodies (LB), and common myelin figures (CMF) at 50%, 68%, and 64%, respectively. In a similar study, we were able to show that LPS also inhibited /sup 3/H-palmitate incorporation by cultured lung cells. LPS-induced suppression of surfactant synthesis was reversed by hydrocortisone. Our results suggest that LPS may play a significant role in reducing surfactant synthesis by rat lung cells, and thus contribute to the pathogenesis of sepsis-related respiratory distress syndrome (RDS) in burn injury.

  14. Exploration of Geometric Noise Suppression in Transition Edge Sensors

    NASA Technical Reports Server (NTRS)

    Chervenak, J. A.; Allen, C. A.; Abrahams, J. A.; Miller, T. M.; Talley, D. J.; Staguhn, J. G.; Benford, D. J.; Mosely, S. H.; Finkbeiner, F. M.; Brekosky, R. G.

    2004-01-01

    We present noise data on Mo/Au superconducting transition edge sensors featuring the noise suppression geometry using normal metal bars transverse to the bias current. The effectiveness of the bars in far-infrared bolometers and x-ray microcalorimeters is evaluated. We have examined the effect of the resistivity of the superconducting bilayer on excess noise in bolometer devices. We have also studied the effect of bar density on energy resolution in x-ray devices. We address the question of whether the reduction is noise is necessarily coupled to a reduction in the effective transition sharpness. We propose a fabrication technique experiment to examine the dependence of alpha and noise suppression in similar transverse bar densities.

  15. Photonic crystal enhancement of auger-suppressed infrared photodetectors

    NASA Astrophysics Data System (ADS)

    Djurić, Zoran; Jakšić, Zoran; Ehrfeld, Wolfgang; Schmidt, Andreas; Matić, Milan; Popović, Mirjana

    2001-04-01

    We examine theoretically and experimentally the possibilities to reach room-temperature background-limited operation of narrow-bandgap compound semiconductor photodetectors in (3-14) micrometer infrared wavelength range. To this purpose we consider the combination of non-equilibrium Auger suppression with photonic crystal enhancement (PCE). This means that Auger generation-recombination processes are suppressed utilizing exclusion, extraction or magnetoconcentration effects or their combination. The residual radiative recombination is removed by immersing the detector active area into a photonic crystal and using the benefits of re-absorption (photon recycling) to effectively increase the radiative lifetime. In this manner the total generation-recombination noise is strongly quenched in sufficiently defect-free device materials. It is concluded that the operation of thus enhanced photonic detectors could even approach signal fluctuation limit.

  16. Suppressing shape instabilities to discover the Bjerknes force instability (L).

    PubMed

    Alibakhshi, Mohammad A; Holt, R Glynn

    2011-11-01

    For sufficiently strong acoustic forcing in a standing wave field, subresonant size bubbles are predicted to be repelled from the pressure antinode. Single bubble sonoluminescence (SBSL) conditions in water do not allow the observation of this instability. This study investigates the possibility that increasing the viscosity of the host liquid can preferentially suppress shape instabilities of a bubble and allow SBSL experiments to be limited by the Bjerknes force instability.

  17. Drug-induced graves disease from CTLA-4 receptor suppression.

    PubMed

    Borodic, Gary; Hinkle, David M; Cia, Yihong

    2011-01-01

    Monoclonal antibody, ipilimumab, useful for treatment of metastatic melanoma, blocks CTLA-4 mediated T-cell suppression and can also cause a Graves ophthalmopathy like syndrome. Epidemiologic study has linked variant polymorphisms of CTLA-4 receptor gene to the presence of thyroid eye disease. The combination of these observations suggests CTLA-4 mediated T-cell functions are important to the pathogenesis of thyroid-associated eye disease.

  18. Suppression of Melanin Production by Expression of HSP70*

    PubMed Central

    Hoshino, Tatsuya; Matsuda, Minoru; Yamashita, Yasuhiro; Takehara, Masaya; Fukuya, Masayo; Mineda, Kazutaka; Maji, Daisuke; Ihn, Hironobu; Adachi, Hiroaki; Sobue, Gen; Funasaka, Yoko; Mizushima, Tohru

    2010-01-01

    Skin hyperpigmentation disorders due to abnormal melanin production induced by ultraviolet (UV) irradiation are both a clinical and cosmetic problem. UV irradiation stimulates melanin production in melanocytes by increasing intracellular cAMP. Expression of heat shock proteins (HSPs), especially HSP70, is induced by various stressors, including UV irradiation, to provide cellular resistance to such stressors. In this study we examined the effect of expression of HSP70 on melanin production both in vitro and in vivo. 3-Isobutyl-1-methylxanthine (IBMX), a cAMP-elevating agent, stimulated melanin production in cultured mouse melanoma cells, and this stimulation was suppressed in cells overexpressing HSP70. IBMX-dependent transcriptional activation of the tyrosinase gene was also suppressed in HSP70-overexpressing cells. Expression of microphthalmia-associated transcription factor (MITF), which positively regulates transcription of the tyrosinase gene, was up-regulated by IBMX; however, this up-regulation was not suppressed in HSP70-overexpressing cells. On the other hand, immunoprecipitation and immunostaining analyses revealed a physical interaction between and co-localization of MITF and HSP70, respectively. Furthermore, the transcription of tyrosinase gene in nuclear extract was inhibited by HSP70. In vivo, UV irradiation of wild-type mice increased the amount of melanin in the basal layer of the epidermis, and this increase was suppressed in transgenic mice expressing HSP70. This study provides the first evidence of an inhibitory effect of HSP70 on melanin production both in vitro and in vivo. This effect seems to be mediated by modulation of MITF activity through a direct interaction between HSP70 and MITF. PMID:20177067

  19. Impedance Matched to Vacuum, Invisible Edge, Diffraction Suppressed Mirror

    NASA Technical Reports Server (NTRS)

    Hagopian, John G. (Inventor); Roman, Patrick A. (Inventor); Shiri, Sharham (Inventor); Wollack, Edward J. (Inventor)

    2015-01-01

    Diffraction suppressed mirrors having an invisible edge are disclosed for incident light at both targeted wavelengths and broadband incident light. The mirrors have a first having at least one discontiguous portion having a plurality of nanostructured apertures. The discontiguous mirror portion impedance matches a relatively high impedance portion of the mirror to a relatively low impedance portion of the mirror, thereby reducing the diffraction edge effect otherwise present in a conventional mirror.

  20. Epigenetic suppression of neprilysin regulates breast cancer invasion

    PubMed Central

    Stephen, H M; Khoury, R J; Majmudar, P R; Blaylock, T; Hawkins, K; Salama, M S; Scott, M D; Cosminsky, B; Utreja, N K; Britt, J; Conway, R E

    2016-01-01

    In women, invasive breast cancer is the second most common cancer and the second cause of cancer-related death. Therefore, identifying novel regulators of breast cancer invasion could lead to additional biomarkers and therapeutic targets. Neprilysin, a cell-surface enzyme that cleaves and inactivates a number of substrates including endothelin-1 (ET1), has been implicated in breast cancer, but whether neprilysin promotes or inhibits breast cancer cell progression and metastasis is unclear. Here, we asked whether neprilysin expression predicts and functionally regulates breast cancer cell invasion. RT–PCR and flow cytometry analysis of MDA-MB-231 and MCF-7 breast cancer cell lines revealed decreased neprilysin expression compared with normal epithelial cells. Expression was also suppressed in invasive ductal carcinoma (IDC) compared with normal tissue. In addition, in vtro invasion assays demonstrated that neprilysin overexpression decreased breast cancer cell invasion, whereas neprilysin suppression augmented invasion. Furthermore, inhibiting neprilysin in MCF-7 breast cancer cells increased ET1 levels significantly, whereas overexpressing neprilysin decreased extracellular-signal related kinase (ERK) activation, indicating that neprilysin negatively regulates ET1-induced activation of mitogen-activated protein kinase (MAPK) signaling. To determine whether neprilysin was epigenetically suppressed in breast cancer, we performed bisulfite conversion analysis of breast cancer cells and clinical tumor samples. We found that the neprilysin promoter was hypermethylated in breast cancer; chemical reversal of methylation in MDA-MB-231 cells reactivated neprilysin expression and inhibited cancer cell invasion. Analysis of cancer databases revealed that neprilysin methylation significantly associates with survival in stage I IDC and estrogen receptor-negative breast cancer subtypes. These results demonstrate that neprilysin negatively regulates the ET axis in breast cancer

  1. Report on a Cooperative Programme on Active Flutter Suppression,

    DTIC Science & Technology

    1980-08-01

    assistance to member nations for the purpose of increasing their scientific and technical potential ; - Recommending effective ways for the member nations to ...experience gained in the above-mentioned wind tunnel tests pointed the way to further improve- ments that could be made in the flutter suppression system...console at Northrop’s Hawthorne facility prior to test entry. The wind tunnel tests were performed in September-October 1979 at the NASA Langley Center

  2. Traumatic Brain Injury and Peripheral Immune Suppression: Primer and Prospectus

    PubMed Central

    Hazeldine, Jon; Lord, Janet M.; Belli, Antonio

    2015-01-01

    Nosocomial infections are a common occurrence in patients following traumatic brain injury (TBI) and are associated with an increased risk of mortality, longer length of hospital stay, and poor neurological outcome. Systemic immune suppression arising as a direct result of injury to the central nervous system (CNS) is considered to be primarily responsible for this increased incidence of infection, a view strengthened by recent studies that have reported novel changes in the composition and function of the innate and adaptive arms of the immune system post-TBI. However, our knowledge of the mechanisms that underlie TBI-induced immune suppression is equivocal at best. Here, after summarizing our current understanding of the impact of TBI on peripheral immunity and discussing CNS-mediated regulation of immune function, we propose roles for a series of novel mechanisms in driving the immune suppression that is observed post-TBI. These mechanisms, which have never been considered before in the context of TBI-induced immune paresis, include the CNS-driven emergence into the circulation of myeloid-derived suppressor cells and suppressive neutrophil subsets, and the release from injured tissue of nuclear and mitochondria-derived damage associated molecular patterns. Moreover, in an effort to further our understanding of the mechanisms that underlie TBI-induced changes in immunity, we pose throughout the review a series of questions, which if answered would address a number of key issues, such as establishing whether manipulating peripheral immune function has potential as a future therapeutic strategy by which to treat and/or prevent infections in the hospitalized TBI patient. PMID:26594196

  3. Mechanism for optical enhancement and suppression of fluorescence.

    PubMed

    Bradshaw, David S; Andrews, David L

    2009-06-18

    When fluorescence from electronically excited states follows the absorption of radiation, the emission spectrum is often a key to identification of the excited species. It now emerges that passing off-resonant laser light through such an electronically excited system may enhance or suppress the fluorescent emission. This report establishes the mechanism and theory for this optical control of spontaneous fluorescence, derived by quantum electrodynamical analysis. Experimental techniques to detect the enhanced signal are also proposed.

  4. Immune Suppression and Inflammation in the Progression of Breast Cancer

    DTIC Science & Technology

    2006-03-01

    420:860. 5. Kusmartsev , S., and D. I. Gabrilovich. 2002. Immature myeloid cells and cancer- associated immune suppression. Cancer Immunol Immunother 51...166:5398. 20. Kusmartsev , S. A., Y. Li, and S. H. Chen. 2000. Gr-1+ myeloid cells derived from tumor-bearing mice inhibit primary T cell activation...Chronic inflammation and cancer. On- cology 16: 217–226. 4. Coussens, L. M., and Z. Werb. 2002. Inflammation and cancer. Nature 420: 860–867. 5. Kusmartsev

  5. Immature myeloid cells and cancer-associated immune suppression.

    PubMed

    Kusmartsev, Sergei; Gabrilovich, Dmitry I

    2002-08-01

    Impaired balance between mature and immature myeloid cells is one of the hallmarks of cancer. In cancer patients as well as in mouse models there is increasing evidence that progressive tumor growth is associated with an accumulation of immature myeloid cells, monocytes/macrophages, and with a decreased number and function of dendritic cells (DC). This review examines recent findings on the contribution of immature myeloid cells (ImC) to cancer-induced immune suppression.

  6. Immune Suppression and Inflammation in the Progression of Breast Cancer

    DTIC Science & Technology

    2008-03-01

    and cancer: back to Virchow? Lancet 2001;357:539-45. 4. Coussens LM, Werb Z. Inflammation and cancer. Nature 2002;420:860-7. 5. Kusmartsev S...Sotomayor EM, Kast WM. Mechanism of immune dysfunction in cancer mediated by immature Gr-1+ myeloid cells. J Immunol 2001;166:5398-406. 40. Kusmartsev S...cancer. Nature 420:860- 867. 5. Kusmartsev , S., and D. I. Gabrilovich. 2002. Immature myeloid cells and cancer- associated immune suppression. Cancer

  7. Chromosome in situ suppression hybridisation in clinical cytogenetics.

    PubMed Central

    Hulten, M A; Gould, C P; Goldman, A S; Waters, J J

    1991-01-01

    The use of chromosome in situ suppression hybridisation with whole chromosome libraries has previously been reported by various research laboratories to be an effective method of identifying specific human chromosomal material. As a clinical cytogenetic service laboratory we have used the technique as a complement to diagnosis by classical chromosome banding. In three examples of structural rearrangements the potential use of the 'chromosome painting' method is assessed for its ability to enhance the routine cytogenetic service currently available. Images PMID:1956055

  8. Increasing enemy biodiversity strengthens herbivore suppression on two plant species.

    PubMed

    Straub, Cory S; Snyder, William E

    2008-06-01

    Concern over biodiversity loss, especially at higher trophic levels, has led to a surge in studies investigating how changes in natural enemy diversity affect community and ecosystem functioning. These studies have found that increasing enemy diversity can strengthen, weaken, and not affect prey suppression, demonstrating that multi-enemy effects on prey are context-dependent. Here we ask how one factor, plant species identity, influences multi-enemy effects on prey. We focused on two plant species of agricultural importance, potato (Solanum tuberosum), and collards (Brassica oleracea L.). These species share a common herbivorous pest, the green peach aphid (Myzus persicae), but vary in structural and chemical traits that affect aphid reproductive rates and which may also influence inter-enemy interactions. In a large-scale field experiment, overall prey exploitation varied dramatically among the plant species, with enemies reducing aphid populations by approximately 94% on potatoes and approximately 62% on collards. Increasing enemy diversity similarly strengthened aphid suppression on both plants, however, and there was no evidence that plant species identity significantly altered the relationship between enemy diversity and prey suppression. Microcosm experiments suggested that, on both collards and potatoes, intraspecific competition among natural enemies exceeded interspecific competition. Enemy species showed consistent and significant differences in where they foraged on the plants, and enemies in the low-diversity treatment tended to spend less time foraging than enemies in the high-diversity treatment. These data suggest that increasing enemy diversity may strengthen aphid suppression because interspecific differences in where enemies forage on the plant allow for greater resource partitioning. Further, these functional benefits of diversity appear to be robust to changes in plant species identity.

  9. Suppression of Rayleigh Taylor instability in strongly coupled plasmas

    SciTech Connect

    Das, Amita; Kaw, Predhiman

    2014-06-15

    The Rayleigh Taylor instability in a strongly coupled plasma medium has been investigated using the equations of generalized hydrodynamics. It is demonstrated that the visco-elasticity of the strongly coupled medium due to strong inter particle correlations leads to a suppression of the Rayleigh Taylor instability unless certain threshold conditions are met. The relevance of these results to experiments on laser compression of matter to high densities including those related to inertial confinement fusion using lasers has also been shown.

  10. Chaos Suppression in a Sine Square Map through Nonlinear Coupling

    NASA Astrophysics Data System (ADS)

    Eduardo, L. Brugnago; Paulo, C. Rech

    2011-11-01

    We study a pair of nonlinearly coupled identical chaotic sine square maps. More specifically, we investigate the chaos suppression associated with the variation of two parameters. Two-dimensional parameter-space regions where the chaotic dynamics of the individual chaotic sine square map is driven towards regular dynamics are delimited. Additionally, the dynamics of the coupled system is numerically characterized as the parameters are changed.

  11. Collective microdynamics and noise suppression in dispersive electron beam transport

    SciTech Connect

    Gover, Avraham; Dyunin, Egor; Duchovni, Tamir; Nause, Ariel

    2011-12-15

    A general formulation is presented for deep collective interaction micro-dynamics in dispersive e-beam transport. In the regime of transversely coherent interaction, the formulation is applicable to both coherent and random temporal modulation of the electron beam. We demonstrate its use for determining the conditions for suppressing beam current noise below the classical shot-noise level by means of transport through a dispersive section with a small momentum compaction parameter.

  12. Weak phase information from the color suppressed modes

    SciTech Connect

    Giri, A. K.; Mawlong, B.; Mohanta, R.

    2007-11-01

    The decay channels , are investigated for extracting weak Cabibbo-Kobayashi-Maskawa (CKM) phase information. These channels are described by color suppressed tree diagrams only and are free from penguin contributions. The branching ratios for these channels are found to be {approx}O(10{sup -5}-10{sup -6}) which can be measured at the currently running B factories. The method presented here may be well suited to determine the CKM angle {gamma}.

  13. Widening Disparity and its Suppression in a Stochastic Replicator Model

    NASA Astrophysics Data System (ADS)

    Sakaguchi, Hidetsugu

    2016-04-01

    Winner-take-all phenomena are observed in various competitive systems. We find similar phenomena in replicator models with randomly fluctuating growth rates. The disparity between winners and losers increases indefinitely, even if all elements are statistically equivalent. A lognormal distribution describes well the nonstationary time evolution. If a nonlinear load corresponding to progressive taxation is introduced, a stationary distribution is obtained and disparity widening is suppressed.

  14. Mechanism of suppression of piperacillin resistance in enterobacteria by tazobactam.

    PubMed

    Kadima, T A; Weiner, J H

    1997-10-01

    Resistance to piperacillin in several isolates of Citrobacter freundii and Enterobacter cloacae was investigated and confirmed to occur at a frequency of 10(-7) to 10(-6). Development of resistance to piperacillin was significantly suppressed by tazobactam but not by clavulanic acid. To elucidate the mechanism by which resistance suppression occurs, the effect of piperacillin plus tazobactam on the induction of AmpC beta-lactamase was analyzed by monitoring the beta-galactosidase activity of an inducible ampC-lacZ gene fusion in Escherichia coli. The combination exerted no inhibitory effect on AmpC beta-lactamase induction. Tazobactam also had no effect on the accumulation of a key intermediate in the AmpC beta-lactamase induction pathway, 1,6-anhydromurotripeptide, in an ampD mutant strain of E. coli. However, the addition of tazobactam to liquid cultures of E. cloacae 40001 in the presence of piperacillin at four times the MIC caused a delay in the recovery of the culture to piperacillin-induced stress. At 16 times the MIC, a complete suppression of regrowth occurred. Analysis of culture viability on piperacillin plates showed that the culture recovery was due to growth by moderately resistant mutants preexisting in the cell population, which at 16 times the MIC became susceptible to the combination. Evidence from the kinetics of inhibition of the E. cloacae 40001 AmpC beta-lactamase by clavulanic acid, sulbactam, and tazobactam and from the effects of these drugs on the frequency of resistance to piperacillin suggests that the suppressive effect of tazobactam on the appearance of resistance is primarily mediated by the beta-lactamase inhibitory activity.

  15. Molecular Mechanisms for Sweet-suppressing Effect of Gymnemic Acids*

    PubMed Central

    Sanematsu, Keisuke; Kusakabe, Yuko; Shigemura, Noriatsu; Hirokawa, Takatsugu; Nakamura, Seiji; Imoto, Toshiaki; Ninomiya, Yuzo

    2014-01-01

    Gymnemic acids are triterpene glycosides that selectively suppress taste responses to various sweet substances in humans but not in mice. This sweet-suppressing effect of gymnemic acids is diminished by rinsing the tongue with γ-cyclodextrin (γ-CD). However, little is known about the molecular mechanisms underlying the sweet-suppressing effect of gymnemic acids and the interaction between gymnemic acids versus sweet taste receptor and/or γ-CD. To investigate whether gymnemic acids directly interact with human (h) sweet receptor hT1R2 + hT1R3, we used the sweet receptor T1R2 + T1R3 assay in transiently transfected HEK293 cells. Similar to previous studies in humans and mice, gymnemic acids (100 μg/ml) inhibited the [Ca2+]i responses to sweet compounds in HEK293 cells heterologously expressing hT1R2 + hT1R3 but not in those expressing the mouse (m) sweet receptor mT1R2 + mT1R3. The effect of gymnemic acids rapidly disappeared after rinsing the HEK293 cells with γ-CD. Using mixed species pairings of human and mouse sweet receptor subunits and chimeras, we determined that the transmembrane domain of hT1R3 was mainly required for the sweet-suppressing effect of gymnemic acids. Directed mutagenesis in the transmembrane domain of hT1R3 revealed that the interaction site for gymnemic acids shared the amino acid residues that determined the sensitivity to another sweet antagonist, lactisole. Glucuronic acid, which is the common structure of gymnemic acids, also reduced sensitivity to sweet compounds. In our models, gymnemic acids were predicted to dock to a binding pocket within the transmembrane domain of hT1R3. PMID:25056955

  16. Nuclear suppression at low energy in relativistic heavy ion collisions

    SciTech Connect

    Das, Santosh K.; Alam, Jan-e; Mohanty, Payal; Sinha, Bikash

    2010-04-15

    The effects of nonzero baryonic chemical potential on the drag and diffusion coefficients of heavy quarks propagating through a baryon-rich quark-gluon plasma have been studied. The nuclear suppression factor R{sub AA} for nonphotonic single-electron spectra resulting from the semileptonic decays of hadrons containing heavy flavors has been evaluated for low-energy collisions. The effect of nonzero baryonic chemical potential on R{sub AA} is highlighted.

  17. Immune Suppression by Dermal Application of JP-8 Jet Fuel

    DTIC Science & Technology

    2008-10-13

    release; distribution unlimited. 13. SUPPLEMENTARY NOTES 14. ABSTRACT The initial focus of this work was to test the hypothesis that dermal application...regulates the production of PGE2 (Pei et al., 1998) we tested the hypothesis that JP-8-induced PAF activates cytokine production and initiates immune...suppression. To test this hypothesis we pre-treated mice with a series of PAF receptor antagonists and then applied JP-8. The PAF receptor antagonists

  18. Vibration suppression for Precision Segmented Reflector backup structure.

    NASA Astrophysics Data System (ADS)

    Chen, G. S.; Garba, J. A.; Wada, B. K.

    1989-09-01

    This paper describes an ongoing effort at the JPL on the vibration suppression for the Precision Segmented Reflector backup structure. The effort is centered on the vibration damping augmentation through a system consisting of active and passive damping members. An active member is a structural member with built-in piezoelectric actuator and sensors. A bridge feedback technique developed in the communication engineering is applied locally to the active member for active damping augmentation.

  19. Suppression of antigen-specific antibody responses in mice ...

    EPA Pesticide Factsheets

    T-cell-dependent antibody responses (TDAR) are suppressed in female C57BL/6N mice exposed to ≥3.75 mg/kg of perfluorooctanoic acid (PFOA) for 15 days. To determine if suppression of humoral immunity by PFOA is peroxisome proliferator activated receptor alpha (PPARa)-dependent and if suppression is associated with specific targeting of T- or B-cells, three separate experiments were conducted: (1) female PPARa constitutive knockout (PPARa KO; B6.129S4-Ppar(tm1Gonz)N12) and wild-type controls (WT; C57BL/6-Tac) exposed to 0, 7.5, or 30 mg PFOA/kg for 15 days were immunized on Day 11 with a T-cell-dependent antigen and sera then collected for measures of antigen-specific lgM titers (TDAR) 5 days later; (2) female C57BL/6N WT mice exposed to 0, 0.94, 1.88, 3.75, or 7.5mg PFOA/kg for 15 days were immunized with a T-cell-independent antigen on Day 11 and sera were then collected foranalyses of antigen-specific lgM titers (TIAR) 7 days later; and (3) splenic lymphocyte phenotypes were assessed in unimmunized female C57BL/6N WT mice exposed to 0, 3.75, or 7.5 mg PFOA/kg for 10 days to investigate effects of PFOA in the absence of specific immunization. Separate groups of mice were immunized with a T-cell-dependent antigen after 11 days of exposure and splenic lymphocyte sub-populations were assessed after 13 or 15 days of exposure to assess numbers of stimulated cells. The results indicated that exposure to ≥1.88mg PFOA/kg suppressed the TIAR; exposure to 30 mg PFOA/k

  20. Suppression of resonance of offshore platform in irregular waves

    SciTech Connect

    Ishida, H.; Komura, T.

    1994-12-31

    A theoretical solution of the vibration of offshore platforms due to irregular waves has been presented by using the equivalent linearized method. This solution has been verified by comparison with the experimental data from the viewpoint of time variation and the spectrum analysis. In the case of irregular waves as well as periodic waves, the resonance can be suppressed by bringing the resonance point close to the cancellation point.

  1. Growth Suppression and Therapy Sensitization of Breast Cancer

    DTIC Science & Technology

    2000-07-01

    Laboratories Inc.), which incorporates an internal ribosome binding site (IRES) and generates a bicistronic message in which the subcloned gene of interest...suppression and apoptosis." Presented at the AACR Special Conference on DNA repair Defects, San Diego CA, January 14- 18, 2000. 12 PROPRIETARY...alter p53 in breast cancer: mutation and nuclear exclusion. Proc. Natl. Acad. Sci., USA 89:7262-7266. 5. Hendersin, I.C., Harris, J.R., Kinne, D.W

  2. Vibration suppression of advanced space cryocoolers: an overview

    NASA Astrophysics Data System (ADS)

    Ross, Ronald G., Jr.

    2003-07-01

    Mechanical cryocoolers represent a significant enabling technology for precision space instruments by providing cryogenic temperatures for sensitive infrared, gamma-ray, and x-ray detectors. However, the vibration generated by the cryocooler's refrigeration compressor has long been identified as a critical integration issue. The key sensitivity is the extent to which the cooler's vibration harmonics excite spacecraft resonances and prevent on-board sensors from achieving their operational goals with respect to resolution and pointing accuracy. To reduce the cryocooler's vibration signature to acceptable levels, a variety of active vibration suppression technologies have been developed and implemented over the past 15 years. At this point, nearly all space cryocoolers have active vibration suppression systems built into their drive electronics that reduce the peak unbalanced forces to less than 1% of their original levels. Typical systems of today individually control the vibration in each of the cryocoolers lowest drive harmonics, with some controlling as many as 16 harmonics. A second vibration issue associated with cryocoolers is surviving launch. Here the same pistons and coldfingers that generate vibration during operation are often the most critical elements in terms of surviving high input acceleration levels. Since electrical power is generally not available during launch, passive vibration suppression technologies have been developed. Common vibration damping techniques include electrodynamic braking via shorted motor coils and the use of particle dampers on sensitive cryogenic elements. This paper provides an overview of the vibration characteristics of typical linear-drive space cryocoolers, outlines their history of development, and presents typical performance of the various active and passive vibration suppression systems being used.

  3. Quantum relays and noise suppression using linear optics

    SciTech Connect

    Jacobs, B.C.; Pittman, T.B.; Franson, J.D.

    2002-11-01

    Probabilistic quantum nondemolition (QND) measurements can be performed using linear optics and postselection. Here we show how QND devices of this kind can be used in a straightforward way to implement a quantum relay, which is capable of extending the range of a quantum cryptography system by suppressing the effects of detector noise. Unlike a quantum repeater, a quantum relay system does not require entanglement purification or the ability to store photons.

  4. Interfering ribonucleic acids that suppress expression of multiple unrelated genes

    PubMed Central

    Passioura, Toby; Gozar, Mary M; Goodchild, Amber; King, Andrew; Arndt, Greg M; Poidinger, Michael; Birkett, Donald J; Rivory, Laurent P

    2009-01-01

    Background Short interfering RNAs (siRNAs) have become the research tool of choice for gene suppression, with human clinical trials ongoing. The emphasis so far in siRNA therapeutics has been the design of one siRNA with complete complementarity to the intended target. However, there is a need for multi-targeting interfering RNA in diseases in which multiple gene products are of importance. We have investigated the possibility of using a single short synthetic duplex RNA to suppress the expression of VEGF-A and ICAM-1; genes implicated in the progression of ocular neovascular diseases such as diabetic retinopathy. Results Duplex RNA were designed to have incomplete complementarity with the 3'UTR sequences of both target genes. One such duplex, CODEMIR-1, was found to suppress VEGF and ICAM-1 by 90 and 60%, respectively in ARPE-19 cells at a transfected concentration of 40 ng/mL. Use of a cyan fusion reporter with target sites constructed in its 3'UTR demonstrated that the repression of VEGF and ICAM-1 by CODEMIR-1 was indeed due to interaction with the target sequence. An exhaustive analysis of sequence variants of CODEMIR-1 demonstrated a clear positive correlation between activity against VEGF (but not ICAM-1) and the length of the contiguous complementary region (from the 5' end of the guide strand). Various strategies, including the use of inosine bases at the sites of divergence of the target sequences were investigated. Conclusion Our work demonstrates the possibility of designing multitargeting dsRNA to suppress more than one disease-altering gene. This warrants further investigation as a possible therapeutic approach. PMID:19531249

  5. Traumatic Brain Injury and Peripheral Immune Suppression: Primer and Prospectus.

    PubMed

    Hazeldine, Jon; Lord, Janet M; Belli, Antonio

    2015-01-01

    Nosocomial infections are a common occurrence in patients following traumatic brain injury (TBI) and are associated with an increased risk of mortality, longer length of hospital stay, and poor neurological outcome. Systemic immune suppression arising as a direct result of injury to the central nervous system (CNS) is considered to be primarily responsible for this increased incidence of infection, a view strengthened by recent studies that have reported novel changes in the composition and function of the innate and adaptive arms of the immune system post-TBI. However, our knowledge of the mechanisms that underlie TBI-induced immune suppression is equivocal at best. Here, after summarizing our current understanding of the impact of TBI on peripheral immunity and discussing CNS-mediated regulation of immune function, we propose roles for a series of novel mechanisms in driving the immune suppression that is observed post-TBI. These mechanisms, which have never been considered before in the context of TBI-induced immune paresis, include the CNS-driven emergence into the circulation of myeloid-derived suppressor cells and suppressive neutrophil subsets, and the release from injured tissue of nuclear and mitochondria-derived damage associated molecular patterns. Moreover, in an effort to further our understanding of the mechanisms that underlie TBI-induced changes in immunity, we pose throughout the review a series of questions, which if answered would address a number of key issues, such as establishing whether manipulating peripheral immune function has potential as a future therapeutic strategy by which to treat and/or prevent infections in the hospitalized TBI patient.

  6. Viral re-suppression and detection of drug resistance following interruption of a suppressive NNRTI-based regimen

    PubMed Central

    Fox, Zoe; Phillips, Andrew; Cohen, Cal; Neuhaus, Jacquie; Baxter, John; Emery, Sean; Hirschel, Bernard; Hullsiek, Kathy Huppler; Stephan, Christoph; Lundgren, Jens

    2009-01-01

    Background Interruption of an NNRTI-regimen is often necessary, but must be performed with caution because NNRTIs have a low genetic barrier to resistance. Limited data exist to guide clinical practice on the best interruption strategy to use. Methods Patients in the drug-conservation arm of SMART who interrupted a fully suppressive NNRTI-regimen were evaluated. From 2003, SMART recommended interruption of an NNRTI by: a staggered-interruption, where the NNRTI was stopped before the NRTIs; or by replacing the NNRTI with another drug before interruption. Simultaneous-interruption of all ARVs was discouraged. Re-suppression rates four-to-eight months after re-initiating NNRTI-therapy were assessed, as was the detection of drug-resistance mutations within two months of the treatment interruption in a subset (N=141). Results Overall, 601/688 (87.4%) patients who re-started an NNRTI achieved viral re-suppression. The adjusted odds ratio (95% CI) for achieving re-suppression was 1.94 (1.02-3.69) for patients with a staggered-interruption and 3.64 (1.37-9.64) for those with a switched-interruption compared to patients with a simultaneous-interruption. At least one NNRTI-mutation was detected in the virus of 16.4% patients with simultaneous-interruption, 12.5% patients with staggered-interruption and 4.2% patients with switched-interruption. Fewer patients with detectable mutations (i.e. 69.2%) achieved HIV-RNA≤400 copies/mL compared to those in whom no mutations were detected (i.e. 86.7%), p=0.05. Conclusions In patients who interrupt a suppressive NNRTI-regimen, the choice of interruption-strategy may influence re-suppression rates when re-starting a similar regimen. NNRTI drug-resistance mutations were observed in a relatively high proportion of patients. These data provide additional support for a staggered- or switched-interruption strategy for NNRTI drugs. PMID:18981767

  7. Transient amplification limits noise suppression in biochemical networks

    NASA Astrophysics Data System (ADS)

    Dixon, John; Lindemann, Anika; McCoy, Jonathan H.

    2016-01-01

    Cell physiology is orchestrated, on a molecular level, through complex networks of biochemical reactions. The propagation of random fluctuations through these networks can significantly impact cell behavior, raising challenging questions about how network design shapes the cell's ability to suppress or exploit these fluctuations. Here, drawing on insights from statistical physics, fluid dynamics, and systems biology, we explore how transient amplification phenomena arising from network connectivity naturally limit a biochemical system's ability to suppress small fluctuations around steady-state behaviors. We find that even a simple system consisting of two variables linked by a single interaction is capable of amplifying small fluctuations orders of magnitude beyond the levels predicted by linear stability theory. We also find that adding additional interactions can promote further amplification, even when these interactions implement classic design strategies known to suppress fluctuations. These results establish that transient amplification is an essential factor determining baseline noise levels in stable intracellular networks. Significantly, our analysis is not bound to specific systems or interaction mechanisms: we find that noise amplification is an emergent phenomenon found near steady states in any network containing sufficiently strong interactions, regardless of its form or function.

  8. Apigenin blocks IKKα activation and suppresses prostate cancer progression.

    PubMed

    Shukla, Sanjeev; Kanwal, Rajnee; Shankar, Eswar; Datt, Manish; Chance, Mark R; Fu, Pingfu; MacLennan, Gregory T; Gupta, Sanjay

    2015-10-13

    IKKα has been implicated as a key regulator of oncogenesis and driver of the metastatic process; therefore is regarded as a promising therapeutic target in anticancer drug development. In spite of the progress made in the development of IKK inhibitors, no potent IKKα inhibitor(s) have been identified. Our multistep approach of molecular modeling and direct binding has led to the identification of plant flavone apigenin as a specific IKKα inhibitor. Here we report apigenin, in micro molar range, inhibits IKKα kinase activity, demonstrates anti-proliferative and anti-invasive activities in functional cell based assays and exhibits anticancer efficacy in experimental tumor model. We found that apigenin directly binds with IKKα, attenuates IKKα kinase activity and suppresses NF-ĸB/p65 activation in human prostate cancer PC-3 and 22Rv1 cells much more effectively than IKK inhibitor, PS1145. We also showed that apigenin caused cell cycle arrest similar to knockdown of IKKα in prostate cancer cells. Studies in xenograft mouse model indicate that apigenin feeding suppresses tumor growth, lowers proliferation and enhances apoptosis. These effects correlated with inhibition of p-IKKα, NF-ĸB/p65, proliferating cell nuclear antigen and increase in cleaved caspase 3 expression in a dose-dependent manner. Overall, our results suggest that inhibition of cell proliferation, invasiveness and decrease in tumor growth by apigenin are mediated by its ability to suppress IKKα and downstream targets affecting NF-ĸB signaling pathways.

  9. Glucocorticoid suppresses the canonical Wnt signal in cultured human osteoblasts

    SciTech Connect

    Ohnaka, Keizo . E-mail: oonaka@geriat.med.kyushu-u.ac.jp; Tanabe, Mizuho; Kawate, Hisaya; Nawata, Hajime; Takayanagi, Ryoichi

    2005-04-01

    To explore the mechanism of glucocorticoid-induced osteoporosis, we investigated the effect of glucocorticoid on canonical Wnt signaling that emerged as a novel key pathway for promoting bone formation. Wnt3a increased the T-cell factor (Tcf)/lymphoid enhancer factor (Lef)-dependent transcriptional activity in primary cultured human osteoblasts. Dexamethasone suppressed this transcriptional activity in a dose-dependent manner, while 1,25-dihydroxyvitamin D3 increased this transcriptional activity. LiCl, an inhibitor of glycogen synthase kinase-3{beta}, also enhanced the Tcf/Lef-dependent transcriptional activity, which was, however, not inhibited by dexamethasone. The addition of anti-dickkopf-1 antibody partially restored the transcriptional activity suppressed by dexamethasone. Dexamethasone decreased the cytosolic amount of {beta}-catenin accumulated by Wnt3a and also inhibited the nuclear translocation of {beta}-catenin induced by Wnt3a. These data suggest that glucocorticoid suppresses the canonical Wnt signal in cultured human osteoblasts, partially through the enhancement of the dickkopf-1 production.

  10. Minoxidil may suppress androgen receptor-related functions

    PubMed Central

    Hsu, Cheng-Lung; Liu, Jai-Shin; Lin, An-Chi; Yang, Chih-Hsun; Chung, Wen-Hung; Wu, Wen-Guey

    2014-01-01

    Although minoxidil has been used for more than two decades to treat androgenetic alopecia (AGA), an androgen-androgen receptor (AR) pathway-dominant disease, its precise mechanism of action remains elusive. We hypothesized that minoxidil may influence the AR or its downstream signaling. These tests revealed that minoxidil suppressed AR-related functions, decreasing AR transcriptional activity in reporter assays, reducing expression of AR targets at the protein level, and suppressing AR-positive LNCaP cell growth. Dissecting the underlying mechanisms, we found that minoxidil interfered with AR-peptide, AR-coregulator, and AR N/C-terminal interactions, as well as AR protein stability. Furthermore, a crystallographic analysis using the AR ligand-binding domain (LBD) revealed direct binding of minoxidil to the AR in a minoxidil-AR-LBD co-crystal model, and surface plasmon resonance assays demonstrated that minoxidil directly bound the AR with a Kd value of 2.6 μM. Minoxidil also suppressed AR-responsive reporter activity and decreased AR protein stability in human hair dermal papilla cells. The current findings provide evidence that minoxidil could be used to treat both cancer and age-related disease, and open a new avenue for applications of minoxidil in treating androgen-AR pathway-related diseases. PMID:24742982

  11. Lenslet array to further suppress starlight for direct exoplanet detection

    NASA Astrophysics Data System (ADS)

    Gong, Qian; McElwain, Michael; Shiri, Ron

    2016-07-01

    Direct imaging plays a key role in the detection and characterization of exoplanets orbiting within its host star's habitable zone. Many innovative ideas for starlight suppression and wavefront control have been proposed and developed over the past decade. However, several technological challenges still lie ahead to achieve the required contrast, including controlling the observatory pointing performance, fabricating occulting masks with tight optical tolerances, developing wavefront control algorithms, controlling stray light, advancing single photon detecting detectors, and integrated system-level issues. This paper explores how a lenslet array and pinhole mask may be implemented to further suppress uncorrected starlight that leaks through the occulting mask. An external occulter, or star shade, is simulated to demonstrate this concept, although this approach can be implemented for internal coronagraphs as well. We describe how to use simple relay optics to control the scene near the inner working angle and the level of the suppression expected. Furthermore, if the lenslet array is the input to an integral field spectrograph, as planned for the WFIRST mission, the spectral content of the exoplanet atmospheres can be obtained to determine if the observed planet is habitable and ultimately, if it is inhabited.

  12. Physical and Chemical Aspects of Fire Suppression in Extraterrestrial Environments

    NASA Technical Reports Server (NTRS)

    Takahashi, F.; Linteris, G. T.; Katta, V. R.

    2001-01-01

    A fire, whether in a spacecraft or in occupied spaces on extraterrestrial bases, can lead to mission termination or loss of life. While the fire-safety record of US space missions has been excellent, the advent of longer duration missions to Mars, the moon, or aboard the International Space Station (ISS) increases the likelihood of fire events, with more limited mission termination options. The fire safety program of NASA's manned space flight program is based largely upon the principles of controlling the flammability of on-board materials and greatly eliminating sources of ignition. As a result, very little research has been conducted on fire suppression in the microgravity or reduced-gravity environment. The objectives of this study are: to obtain fundamental knowledge of physical and chemical processes of fire suppression, using gravity and oxygen concentration as independent variables to simulate various extraterrestrial environments, including spacecraft and surface bases in Mars and moon missions; to provide rigorous testing of analytical models, which include comprehensive descriptions of combustion and suppression chemistry; and to provide basic research results useful for technological advances in fire safety, including the development of new fire-extinguishing agents and approaches, in the microgravity environment associated with ISS and in the partial-gravity Martian and lunar environments.

  13. Bone mineral density in premenopausal women receiving levothyroxine suppressive therapy.

    PubMed

    Nuzzo, V; Lupoli, G; Esposito Del Puente, A; Rampone, E; Carpinelli, A; Del Puente, A E; Oriente, P

    1998-10-01

    Osteoporosis is a well-known complication of thyrotoxicosis. Prolonged subclinical hyperthyroidism due to L-thyroxine treatment has been associated with reduced bone mass and thus with the potential risk of premature development of osteoporosis. The aim of this study was to assess the effect of a chronic L-thyroxine suppressive treatment on bone mineral density (BMD) in a group of premenopausal women. Forty consecutive patients (mean age +/- SE = 40.95 +/- 1.56 years) affected by non-toxic goiter underwent bone mineral densitometry (dual energy X-ray absorptiometry; DEXA) of the lumbar spine (L1-L4) and right femoral neck. At the time of the study the patients had been under thyroid stimulating hormone (TSH) suppressive therapy for 74.95 +/- 10.34 months (range 17-168 months). Baseline levels of free thyroxine (fT4), free triiodothyronine (fT3), TSH, calcium and phosphorus were measured and correlated with BMD. The age of starting, duration of treatment, main daily dose, cumulative dose of treatment and body mass index (BMI) were also correlated with BMD. Statistical analysis was performed by multiple linear regression. BMD among female patients was not significantly different from that of the general population matched for age and sex. With the use of the regression model, no significant correlation was found between BMD and the variables considered. In conclusion, our data suggest that L-thyroxine suppressive therapy, if carefully carried out and monitored, has no significant effect on bone mass.

  14. Sigma Receptors Suppress Multiple Aspects of Microglial Activation

    PubMed Central

    Hall Aaron, A.; Yelenis, Herrera; Ajmo Craig, T.; Javier, Cuevas; Pennypacker Keith, R.

    2009-01-01

    During brain injury, microglia become activated and migrate to areas of degenerating neurons. These microglia release pro-inflammatory cytokines and reactive oxygen species causing additional neuronal death. Microglia express high levels of sigma receptors, however, the function of these receptors in microglia and how they may affect the activation of these cells remain poorly understood. Using primary rat microglial cultures, it was found that sigma receptor activation suppresses the ability of microglia to rearrange their actin cytoskeleton, migrate, and release cytokines in response to the activators adenosine triphosphate (ATP), monocyte chemoattractant protein 1 (MCP-1), and lipopolysaccharide (LPS). Next, the role of sigma receptors in the regulation of calcium signaling during microglial activation was explored. Calcium fluorometry experiments in vitro show that stimulation of sigma receptors suppressed both transient and sustained intracellular calcium elevations associated with the microglial response to these activators. Further experiments showed that sigma receptors suppress microglial activation by interfering with increases in intracellular calcium. In addition, sigma receptor activation also prevented membrane ruffling in a calcium-independent manner, indicating that sigma receptors regulate the function of microglia via multiple mechanisms. PMID:19031439

  15. Penfluridol suppresses pancreatic tumor growth by autophagy-mediated apoptosis

    PubMed Central

    Ranjan, Alok; Srivastava, Sanjay K.

    2016-01-01

    Pancreatic tumors exhibit enhanced autophagy as compared to any other cancer, making it resistant to chemotherapy. We evaluated the effect of penfluridol against pancreatic cancer. Penfluridol treatment induced apoptosis and inhibited the growth of Panc-1, BxPC-3 and AsPC-1, pancreatic cancer cells with IC50 ranging between 6–7 μM after 24 h of treatment. Significant autophagy was induced by penfluridol treatment in pancreatic cancer cells. Punctate LC3B and autophagosomes staining confirmed autophagy. Inhibiting autophagy by chloroquine, bafilomycin, 3-methyladenine or LC3BsiRNA, significantly blocked penfluridol-induced apoptosis, suggesting that autophagy lead to apoptosis in our model. Penfluridol treatment suppressed the growth of BxPC-3 tumor xenografts by 48% as compared to 17% when treated in combination with chloroquine. Similarly, penfluridol suppressed the growth of AsPC-1 tumors by 40% versus 16% when given in combination with chloroquine. TUNEL staining and caspase-3 cleavage revealed less apoptosis in the tumors from mice treated with penfluridol and chloroquine as compared to penfluridol alone. Penfluridol treatment also suppressed the growth of orthotopically implanted Panc-1 tumors by 80% by inducing autophagy-mediated apoptosis in the tumors. These studies established that penfluridol inhibits pancreatic tumor growth by autophagy-mediated apoptosis. Since penfluridol is already in clinic, positive findings from our study will accelerate its clinical development. PMID:27189859

  16. Model of ELM suppression by RMPs in DIII-D

    NASA Astrophysics Data System (ADS)

    Callen, J. D.; Nazikian, R.; Ferraro, N. M.; Beidler, M. T.; Hegna, C. C.; La Haye, R. J.; Paz-Soldan, C.

    2016-10-01

    Recent DIII-D experiments explored effects of resonant magnetic perturbations (RMPs) near the minimum applied n=2 RMP amplitude required for ELM suppression in ITER-relevant low collisionality pedestals. Comprehensive tokamak forced magnetic reconnection (FMR) theory is used to describe and quantify the many physical processes involved in stages of RMP effects and an ELM crash response that lead to bifurcation into an ELM-suppressed state: 1) in ELMing equilibrium, flow-screening is strong with little magnetic reconnection; 2) the RMP at q=8/2 penetrates via FMR induced by an ELM crash and locks toroidal flow to the lab frame (like error field mode locking); 3) the ELM crash provides a 8/2 seed island (like NTMs) governed by a modified Rutherford equation; 4) if the total 8/2 RMP is large enough the internal tearing response and flow bifurcate and grow; and 5) flutter transport reduces pedestal top gradients which stabilizes P-B modes and hence suppresses ELMs. This analysis is for discharge 158115 in DIII-D; its potential universality is yet to be determined. Work supported by OFES/DOE under DE-FG02-92ER54139, DE-FG02-86ER53218, DE-AC02-09CH11466 and DE-FC02-04ER54698.

  17. RAGE Suppresses ABCG1-Mediated Macrophage Cholesterol Efflux in Diabetes

    PubMed Central

    Daffu, Gurdip; Shen, Xiaoping; Senatus, Laura; Thiagarajan, Devi; Abedini, Andisheh; Hurtado del Pozo, Carmen; Rosario, Rosa; Song, Fei; Friedman, Richard A.; Ramasamy, Ravichandran

    2015-01-01

    Diabetes exacerbates cardiovascular disease, at least in part through suppression of macrophage cholesterol efflux and levels of the cholesterol transporters ATP binding cassette transporter A1 (ABCA1) and ABCG1. The receptor for advanced glycation end products (RAGE) is highly expressed in human and murine diabetic atherosclerotic plaques, particularly in macrophages. We tested the hypothesis that RAGE suppresses macrophage cholesterol efflux and probed the mechanisms by which RAGE downregulates ABCA1 and ABCG1. Macrophage cholesterol efflux to apolipoprotein A1 and HDL and reverse cholesterol transport to plasma, liver, and feces were reduced in diabetic macrophages through RAGE. In vitro, RAGE ligands suppressed ABCG1 and ABCA1 promoter luciferase activity and transcription of ABCG1 and ABCA1 through peroxisome proliferator–activated receptor-γ (PPARG)–responsive promoter elements but not through liver X receptor elements. Plasma levels of HDL were reduced in diabetic mice in a RAGE-dependent manner. Laser capture microdissected CD68+ macrophages from atherosclerotic plaques of Ldlr−/− mice devoid of Ager (RAGE) displayed higher levels of Abca1, Abcg1, and Pparg mRNA transcripts versus Ager-expressing Ldlr−/− mice independently of glycemia or plasma levels of total cholesterol and triglycerides. Antagonism of RAGE may fill an important therapeutic gap in the treatment of diabetic macrovascular complications. PMID:26253613

  18. Hearing smiles and smile suppression in natural speech

    NASA Astrophysics Data System (ADS)

    Drahota, Amy K.; Reddy, Vasudevi

    2003-04-01

    That we can hear smiles in speech is an established finding. However smiles in natural speech can be of many different kinds, serving different social functions. Previous research has focused only on one category of smile using either smiles ``posed'' during speech or degraded samples of smiling speech (to disguise the content of utterances). The present study used naturally occurring speech in three foreign languages (Czech, Spanish, and Finnish) and in English, presented to naive native English speakers. Preliminary analyses extracted two kinds of smiles in speech-``open smiles'' and ``suppressed smiles'' in contrast to speech with ``no smiles.'' Eighty listeners were presented with 18 audio-clips (six of each type) in randomized order. ``No smiles'' and ``open smiles'' were successfully identified across all languages. ``Suppressed smiles'' were most often coded as ``no smiles.'' An exploration of the pitch contours showed that ``suppressed smiles'' had a higher average pitch similar to ``open smiles,'' but a significantly higher variance in pitch range than others. Natural speech produces smiles serving very different functions. The auditory expression and perceivability of emotion is likely to be influenced by subtle social functions only evident in natural interactions.

  19. Viral degradasome hijacks mitochondria to suppress innate immunity

    PubMed Central

    Goswami, Ramansu; Majumdar, Tanmay; Dhar, Jayeeta; Chattopadhyay, Saurabh; Bandyopadhyay, Sudip K; Verbovetskaya, Valentina; Sen, Ganes C; Barik, Sailen

    2013-01-01

    The balance between the innate immunity of the host and the ability of a pathogen to evade it strongly influences pathogenesis and virulence. The two nonstructural (NS) proteins, NS1 and NS2, of respiratory syncytial virus (RSV) are critically required for RSV virulence. Together, they strongly suppress the type I interferon (IFN)-mediated innate immunity of the host cells by degrading or inhibiting multiple cellular factors required for either IFN induction or response pathways, including RIG-I, IRF3, IRF7, TBK1 and STAT2. Here, we provide evidence for the existence of a large and heterogeneous degradative complex assembled by the NS proteins, which we named “NS-degradasome” (NSD). The NSD is roughly ∼300-750 kD in size, and its degradative activity was enhanced by the addition of purified mitochondria in vitro. Inside the cell, the majority of the NS proteins and the substrates of the NSD translocated to the mitochondria upon RSV infection. Genetic and pharmacological evidence shows that optimal suppression of innate immunity requires mitochondrial MAVS and mitochondrial motility. Together, we propose a novel paradigm in which the mitochondria, known to be important for the innate immune activation of the host, are also important for viral suppression of the innate immunity. PMID:23877405

  20. Coping with fear through suppression and avoidance of threatening information.

    PubMed

    Nielsen, Jesper; Shapiro, Stewart

    2009-09-01

    Fear appeal communications are widely used by social marketers in their efforts to persuade individuals to refrain from engaging in risky behaviors. The present research shows that exposure to a fear appeal can lead to the suppression of concepts semantically related to the threat and bias attentional resources away from threat-relevant information. Participants in the experimental condition viewed a fear appeal advertisement depicting the negative consequences of drinking and driving. The results of a reaction time task showed inhibited responses to words semantically related to drinking (e.g., beer, party) relative to a baseline group that controlled for priming effects (Experiment 1a) and level of fear (Experiment 1b). Furthermore, those in the experimental condition were shown to adopt an attention avoidance processing style, decreasing attention to alcohol-related advertisements appearing in a mock magazine (Experiments 2a and 2b). Because processing of alcohol-related advertising has been linked previously to an increase in drinking and driving, inhibited processing of such advertisements suggests a positive outcome of suppression effects. This contrasts with prior claims suggesting that suppression is counter to prevention-based efforts.