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Sample records for polar auroras glow

  1. Polarization of Hazes and Aurorae on Jupiter

    Science.gov (United States)

    Yanamandra-Fisher, Padma A.; McLean, Will; PACA_Jupiter

    2017-10-01

    Our solar system planets show a large variety of atmospheric polarization properties, from the thick, highly polarizing haze on Titan and the poles of Jupiter, Rayleigh scattering by molecules on Uranus and Neptune, to clouds in the equatorial region of Jupiter or on Venus. Changes in the clouds/thermal filed can be brought about by endogenic dynamical processes such merger of vortices; global, planetary scale upheavals, and external factors such as celestial collisions (such as D/Shoemaker-Levy 9 impact with Jupiter in 1994, etc.). Although the range of phase angles available from Earth for outer planets is restricted to a narrow range, limb polarization measurements provide constraints on the polarimetric properties. For example, at the equator, much of the observed reflected radiation is due to the presence of clouds and therefore, low polarization. Polar asymmetry exists between the two poles, while the planetary disk is unpolarized. Jupiter is known to exhibit a strong polar limb polarization and a low equatorial limb polarization due to the presence of haze particles and Rayleigh scattering at the poles. In contrast, at the equator, the concentration of particulates in the high atmosphere might change, changing the polarimetric signature and aurorae at both poles. The polarimetric maps, in conjunction with thermal maps and albedo maps, can provide constraints on modeling efforts to understand the nature of the aerosols/hazes in Jovian atmosphere. With Jupiter experiencing morphological changes at many latitudes, we have initiated a polarimetric observing campaign of Jupiter, in conjunction with The PACA Project. With NASA/Juno mission in a 53-day orbit around Jupiter, and recent outbreaks in the atmosphere, changes in the polarimetric signature will provide insight to the changes occurring in the atmosphere. Some of our observations are acquired by a team of professional/amateur planetary imagers astronomers based in the U.K., Australia and Europe. France

  2. The theta aurora and ionospheric flow convection: Polar ultraviolet imager and SuperDARN radar observations

    Science.gov (United States)

    Liou, K.; Ruohoniemi, J. M.; Newell, P. T.; Meng, C. I.

    2003-12-01

    We report results from a case study of the theta aurora that occurred during a magnetic cloud event on November 8, 2000. The interplanetary magnetic field (IMF) was strongly northward for more than 12 hours, while the y-component of IMF changed signs several times. Auroral images from the Ultraviolet Imager on board the Polar satellite show clear instances of theta auroras during the prolonged northward IMF period. This event provides a good opportunity for testing current models of theta aurora generation and evolution. We examine in situ particle data from the DMSP satellites to find magnetospheric source regions responsible for the theta auroras. We also examine ionospheric plasma flow convection data from the SuperDARN radar network to study relationships between the ionospheric plasma flow pattern and the location of the theta auroras. Our results clearly indicate that the theta aurora bar, at least on nightside, was located in a region of anti-sunward convecting flow. This is not consistent with the current view that theta auroras reside in regions of closed field lines and hence in regions of sunward convecting flow. Implication of the new findings will be discussed.

  3. Integrating Felting in Elementary Science Classrooms to Facilitate Understanding of the Polar Auroras

    Directory of Open Access Journals (Sweden)

    Brandy Terrill

    2017-10-01

    Full Text Available The Next Generation Science Standards (NGSS emphasize conceptual science instruction that draws on students’ ability to make observations, explain natural phenomena, and examine concept relationships. This paper explores integrating the arts, in the form of felting, in elementary science classrooms as a way for students to model and demonstrate understanding of the complex scientific processes that cause the polar auroras. The steps for creating felting, and using the felting artwork students create for assessing science learning, are described.

  4. Drilling Polar Oceans with the European Research Icebreaker AURORA BOREALIS: the IODP Context

    Science.gov (United States)

    Lembke-Jene, Lester; Wolff-Boenisch, Bonnie; Azzolini, Roberto; Thiede, Joern; Biebow, Nicole; Eldholm, Olav; Egerton, Paul

    2010-05-01

    Polar oceans are characterized by extreme environmental conditions for humans and materials, and have remained the least accessible regions to scientists of the IODP. DSDP and ODP have for long faced specific technical and logistical problems when attempting to drill in ice-covered polar deep-sea basins. The Arctic Ocean and large areas of the high-latitude Southern Ocean remained largely un-sampled by ODP and remain one of the major scientific and technological challenges for IODP. Drilling in these regions has been discussed and anticipated for decades and the scientific rationales are reflected in the science plans of the international Nansen Arctic Drilling Program (NAD) or the Arctic Program Planning Group (APPG) of ODP/IODP, amongst others. More recently, the rationale to investigate the polar oceans in a holistic approach has been outlined by workshops, leading to strategic assessments of the scientific potential and new drilling proposals. The European Polar Board took the initiative to develop a plan for a novel and dedicated research icebreaker with technical capabilities hitherto unrealised. This research icebreaker will enable autonomous operations in the central Arctic Ocean and the Southern Ocean, even during the severest ice conditions in the deep winter, serving all marine disciplines of polar research including scientific drilling: The European Research Icebreaker and Deep-Sea Drilling Vessel AURORA BOREALIS. AURORA BOREALIS is presently planned as a multi-purpose vessel. The ship can be deployed as a research icebreaker in all polar waters during any season of the year, as it shall meet the specifications of the highest ice-class attainable (IACS Polar Code 1) for icebreakers. During the times when it is not employed for drilling, it will operate as the most technically advanced multi-disciplinary research vessel in the Arctic or polar Southern Ocean. AURORA BOREALIS will be a "European scientific flagship facility" (fully open to non

  5. Breaking the Ice: Strategies for Future European Research in the Polar Oceans - The AURORA BOREALIS Concept

    Science.gov (United States)

    Lembke-Jene, L.; Biebow, N.; Wolff-Boenisch, B.; Thiede, J.; European Research Icebreaker Consortium

    2011-12-01

    Research vessels dedicated to work in polar ice-covered waters have only rarely been built. Their history began with Fritjof Nansen's FRAM, which he used for his famous first crossing of the Arctic Ocean 1893-1896. She served as example for the first generation of polar research vessels, at their time being modern instruments planned with foresight. Ice breaker technology has developed substantially since then. However, it took almost 80 years until this technical advance also reached polar research, when the Russian AKADEMIK FEDEROV, the German POLARSTERN, the Swedish ODEN and the USCG Cutter HEALY were built. All of these house modern laboratories, are ice-breakers capable to move into the deep-Arctic during the summer time and represent the second generation of dedicated polar research vessels. Still, the increasing demand in polar marine research capacities by societies that call for action to better understand climate change, especially in the high latitudes is not matched by adequate facilities and resources. Today, no icebreaker platform exists that is permanently available to the international science community for year-round expeditions into the central Arctic Ocean or heavily ice-infested waters of the polar Southern Ocean around Antarctica. The AURORA BOREALIS concept plans for a heavy research icebreaker, which will enable polar scientists around the world to launch international research expeditions into the central Arctic Ocean and the Antarctic continental shelf seas autonomously during all seasons of the year. The European Research Icebreaker Consortium - AURORA BOREALIS (ERICON-AB) was established in 2008 to plan the scientific, governance, financial, and legal frameworks needed for the construction and operation of this first multi-nationally owned and operated research icebreaker and polar scientific drilling platform. By collaborating together and sharing common infrastructures it is envisioned that European nations make a major contribution to

  6. Jupiter's magnetosphere and aurorae observed by the Juno spacecraft during its first polar orbits

    DEFF Research Database (Denmark)

    Connerney, J. E. P.; Adriani, Alberto; Allegrini, F.

    2017-01-01

    for Juno's passage over the poles and traverse of Jupiter's hazardous inner radiation belts. Juno's energetic particle and plasma detectors measured electrons precipitating in the polar regions, exciting intense aurorae, observed simultaneously by the ultraviolet and infrared imaging spectrographs. Juno...... transited beneath the most intense parts of the radiation belts, passed about 4000 kilometers above the cloud tops at closest approach, well inside the jovian rings, and recorded the electrical signatures of high-velocity impacts with small particles as it traversed the equator....

  7. A rate-equation model for polarized laser-induced fluorescence to measure electric field in glow discharge He plasmas

    International Nuclear Information System (INIS)

    Takiyama, K.; Watanabe, M.; Oda, T.

    1998-01-01

    Possibility of applying polarized laser-induced fluorescence (LIF) spectroscopy for measuring the electric field in a plasma with a large collisional depolarization has been investigated. A rate equation model including the depolarization process was employed to analyze the time evolution of LIF polarization components. The polarized LIF pulse shapes observed in the sheath of a He glow discharge plasma were successfully reproduced, and the electric field distribution was obtained with high accuracy. (author)

  8. Jupiter's magnetosphere and aurorae observed by the Juno spacecraft during its first polar orbits.

    Science.gov (United States)

    Connerney, J E P; Adriani, A; Allegrini, F; Bagenal, F; Bolton, S J; Bonfond, B; Cowley, S W H; Gerard, J-C; Gladstone, G R; Grodent, D; Hospodarsky, G; Jorgensen, J L; Kurth, W S; Levin, S M; Mauk, B; McComas, D J; Mura, A; Paranicas, C; Smith, E J; Thorne, R M; Valek, P; Waite, J

    2017-05-26

    The Juno spacecraft acquired direct observations of the jovian magnetosphere and auroral emissions from a vantage point above the poles. Juno's capture orbit spanned the jovian magnetosphere from bow shock to the planet, providing magnetic field, charged particle, and wave phenomena context for Juno's passage over the poles and traverse of Jupiter's hazardous inner radiation belts. Juno's energetic particle and plasma detectors measured electrons precipitating in the polar regions, exciting intense aurorae, observed simultaneously by the ultraviolet and infrared imaging spectrographs. Juno transited beneath the most intense parts of the radiation belts, passed about 4000 kilometers above the cloud tops at closest approach, well inside the jovian rings, and recorded the electrical signatures of high-velocity impacts with small particles as it traversed the equator. Copyright © 2017, American Association for the Advancement of Science.

  9. Dayside aurorae and polar arcs under south-east IMF orientation

    Directory of Open Access Journals (Sweden)

    P. E. Sandholt

    2006-12-01

    Full Text Available We document a characteristic spatial and temporal structure of the aurora in the postnoon sector present during a 10-h-long interval of very steady southeast IMF orientation (clock angle=135° ending in a sharp south-to-north transition. Focus is placed on the detailed morphology of auroral forms/activities corresponding to merging and lobe convection cells obtained from SuperDARN convection data and Greenland magnetograms. The ground optical instruments at Ny Ålesund, Svalbard (76° MLAT recorded different auroral forms/activities as the station moved to higher magnetic local times (MLTs in the 13:00–17:00 MLT sector. Whereas the 13:00–15:00 MLT sector is characterized by classical poleward moving auroral forms (PMAFs associated with merging cell transients, the aurora in the 15:00–17:00 MLT sector shows instead a characteristic latitudinal bifurcation consisting of standard oval forms and polar arcs, and a corresponding composite pattern of merging and lobe convection cells. The merging and lobe cells respond to the southward and northward IMF transitions by activation/fading and fading/activation, respectively. A sequence of brightening events is characterized by successive activations progressing in latitude from the merging cell regime to the lobe cell regime. Emphasis is placed on the association between polar arc brightenings and the activation of the channel of enhanced sunward flow in the lobe cell. The observations are discussed in relation to recent work on solar wind-magnetosphere-ionosphere interconnection topology.

  10. Multi-instrument observation of two different types of polar cap aurora occurring simultaneously during northward IMF

    Science.gov (United States)

    Reidy, J. A.; Fear, R. C.; Lanchester, B. S.; Whiter, D. K.; Kavanagh, A. J.; Paxton, L. J.; Zhang, Y.

    2016-12-01

    Polar cap aurora are a phenomena associated with periods of northwards IMF. By studying their appearance and formation, we can gain valuable information on the configuration of Earth's magnetosphere during the less understood `quiet' periods that occur approximately half of the time. Observations of high latitude aurora from multiple instruments on 19 January 2008 are presented, including almost simultaneous observations of the northern and southern auroral regions from the Special Sensor Ultra-violet Spectrographic Imager (SSUSI) instruments on board Defence Meteorological Satellite Programme (DMSP) spacecraft F16 and F17. SuperDARN flows are also explored in both hemispheres during the event. In the northern hemisphere, two high latitude structures were seen on opposite sides of the polar cap during the same interval. The energies of the precipitating electrons above the structure on the duskside was estimated to vary between 2-11 keV using the Auroral Structure and Kinetics (ASK) instrument in conjunction with the Southampton ion chemistry model. Further analysis of this structure revealed it to be formed on closed field lines that had protruded into the polar cap, consistent with the mechanism proposed for transpolar arcs. However this structure did not cross the entire polar cap but remained, in the northern hemisphere, at approximately 80° magnetic latitude for at least 40 minutes. This protrusion is hence suggested to be an example of a `failed transpolar arc'. The structure seen on the dawnside of the northern polar cap was analysed using DMSP particle spectrograph data. It was found to be associated with electron precipitation energies lower than 1 keV and no ion signature were present. Hence it is suggested that this sun-aligned structure is consistent with the common low intensity arcs formed by accelerated polar rain. The study shows there are at least two types of high latitude aurora occurring simultaneously during northwards IMF.

  11. From the sun's corona to the polar cusp aurora above Svalbard. Interplanetary and terrestrial effects of a coronal transient

    International Nuclear Information System (INIS)

    Sandholt, P.E.

    1986-08-01

    The report presents a study of the flare-related coronal transient of Nov. 27, 1979, with the resulting interplanetary (IP) shock, and the associated auroral and magnetic effects that were observed from the ground 72 hours after the initial coronal brightening. The observed disturbance of the interplanetary magnetic field (IMF) resulting from the coronal mass ejection is discussed in relation to a model discription of flare-related perturbations of the solar current sheet. The power transfer from the solar wind to the magnetosphere did not rise above the treshold value for magnetospheric strom triggering in this case. thus, the IP shock was not followed by a major storm. However, distinct signatures related to the IP disturbance were observed in the polar cusp aurorae above Svaldbard and in the local magnetic field. The dynamical behaviour of the cusp aurora is discussed in relation to different models of plasma transfer across the dayside magnetopause, from the shocked solar wind to the magnetosphere. A detailed analysis of the available information from interplanetary space and the ground indicates that the main auroral dynamics observed in this case are related to localized, impulsive plasma injections associated with flux transfer events

  12. Polar Bear UV Imaging of Airglow and Aurora - Image Processing and Results

    Science.gov (United States)

    1989-09-24

    L., Huffman, R. E., Rich, F. J., Meng, C. - I., Potocki , K. A., Potemra, T. A., Hanson, W. B., Heelis, R. A., and Wittwer, L. A., The HILAT program...0177, ADA214203 [13) Osnovich, I., and Tur, M., Stabilising the Polar BEAR Retrospectively, Research Progress and Forecast Report to AFGL, Jan . 1989

  13. Microstructural and optical properties of A-Si: H deposited by DC plasma glow discharge of electrode polarity

    International Nuclear Information System (INIS)

    Salam, R.; Danker, A.R.

    1993-01-01

    A method for deducing the density of valence electrons and the average atomic separation of Si atoms in a-Si:H are presented. Refractive index and optical absorption experimental data on a variety of dc glow discharge deposited a-Si:H samples are utilized to deduce the two parameters. The density of valence electrons depict values in the range (1.47-6.15)x10 22 cm -3 while the average atomic spacing varies within 3.13-4.61 A. The existence of microvoids and regions of rich silicon-hydride phase are proposed to account for this. Comparisons of the electrical conductivity, optical parameters and vibrational modes are done for cathode and anode deposited a-Si:H samples. Conductivity for both types of samples are the same at around 1.3x10 -9 (Ωcm) -1 , but significant differences are observed in the values of the refractive index n and the optical gap Eg of the cathode (4.06, 1.95 eV) and anode (3.13, 2.34 eV) samples. Observations on the infrared spectrum of the two a-Si:H samples suggests that the anode sample contain appreciable amount and a higher proportion of oxygen, as identified by the 2080cm -1 shift of the Si-H stretching mode, while a strong Si-H 3 symmetric deformation mode is proposed to occur in the cathode sample

  14. Multi-site observations of the association between aurora and plasma convection in the cusp/polar cap during a southeastward(By ~ |Bz| IMF orientation

    Directory of Open Access Journals (Sweden)

    P. E. Sandholt

    2003-02-01

    Full Text Available In a case study we demonstrate the spatiotemporal structure of aurora and plasma convection in the cusp/polar cap when the interplanetary magnetic field (IMF Bz < 0 and By ~ | Bz | (clock angle in GSM Y - Z plane: ~ 135°. This IMF orientation elicited a response different from that corresponding to strongly northward and southward IMF. Our study of this "intermediate state" is based on a combination of ground observations of optical auroral emissions and ionospheric plasma convection. Utilizing all-sky cameras at NyAlesund, Svalbard and Heiss Island (Russian arctic, we are able to monitor the high-latitude auroral activity within the ~10:00–15:00 MLT sector. Information on plasma convection is obtained from the SuperDARN radars, with emphasis placed on line of sight observations from the radar situated in Hankasalmi, Finland (Cutlass. A central feature of the auroral observations in the cusp/polar cap region is a ~ 30-min long sequence of four brightening events, some of which consists of latitudinally and longitudinally separated forms, which are found to be associated with pulsed ionospheric flows in merging and lobe convection cells. The auroral/convection events may be separated into different forms/cells and phases, reflecting a spatiotem-poral evolution of the reconnection process on the dayside magnetopause. The initial phase consists of a brightening in the postnoon sector (~ 12:00–14:00 MLT at ~ 73° MLAT, accompanied by a pulse of enhanced westward convection in the postnoon merging cell. Thereafter, the event evolution comprises two phenomena which occur almost simultaneously: (1 westward expansion of the auroral brightening (equatorward boundary intensification across noon, into the ~ 10:00–12:00 MLT sector, where the plasma convection subsequently turns almost due north, in the convection throat, and where classical poleward moving auroral forms (PMAFs are observed; and (2 auroral brightening at slightly higher latitudes

  15. Aurorae. Firework in the sky. 2. upd. ed.

    International Nuclear Information System (INIS)

    Pfoser, Andreas; Eklund, Tom

    2013-01-01

    Aurorae are fascinating phenomena. As aurora borealis and aurora australis occurring in the polar regions of both earth hemispheres, their incessant color and shape games put people in wonder. The meteorologist Andreas Pfoser explains the physical connections, which lead to the formation of this natural phenomenon. The link with the activity of the sun and the interaction in the earth atmosphere are explained detailedly and understandably. The fantastic recordings, presented in generous horizontal format has collected the Finnish aurora photographer Tom Eklund over a period of time of 14 years. Thereby it succeeded, to document also some events, the origin of which on our daystar were recorded by solar satellites, so that the sequence of events from the solar eruption until the aurora spectacle can be reproduced. The present 2nd edition contains new scientific findings. Additionally numerous aurora pictures were replaced by more actual photos created with modern technology.

  16. Hubble Provides Clear Images of Saturn's Aurora

    Science.gov (United States)

    1998-01-01

    This is the first image of Saturn's ultraviolet aurora taken by the Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope in October 1997, when Saturn was a distance of 810 million miles (1.3 billion kilometers) from Earth. The new instrument, used as a camera, provides more than ten times the sensitivity of previous Hubble instruments in the ultraviolet. STIS images reveal exquisite detail never before seen in the spectacular auroral curtains of light that encircle Saturn's north and south poles and rise more than a thousand miles above the cloud tops.Saturn's auroral displays are caused by an energetic wind from the Sun that sweeps over the planet, much like the Earths aurora that is occasionally seen in the nighttime sky and similar to the phenomenon that causes fluorescent lamps to glow. But unlike the Earth, Saturn's aurora is only seen in ultraviolet light that is invisible from the Earths surface, hence the aurora can only be observed from space. New Hubble images reveal ripples and overall patterns that evolve slowly, appearing generally fixed in our view and independent of planet rotation. At the same time, the curtains show local brightening that often follow the rotation of the planet and exhibit rapid variations on time scales of minutes. These variations and regularities indicate that the aurora is primarily shaped and powered by a continual tug-of-war between Saturn's magnetic field and the flow of charged particles from the Sun.Study of the aurora on Saturn had its beginnings just seventeen years ago. The Pioneer 11 spacecraft observed a far-ultraviolet brightening on Saturn's poles in 1979. The Saturn flybys of the Voyager 1 and 2 spacecraft in the early 1980s provided a basic description of the aurora and mapped for the first time planets enormous magnetic field that guides energetic electrons into the atmosphere near the north and south poles.The first images of Saturn's aurora were provided in 1994-5 by the Hubble Space

  17. Interplanetary shock induced ring current auroras

    Science.gov (United States)

    Zhang, Yongliang; Paxton, Larry J.; Zheng, Yihua

    2008-01-01

    On 21 January 2005, a fast interplanetary (IP) shock compressed the magnetosphere and caused detached auroras (DA) on the dayside, duskside and nightside ionosphere. The DA were detected by three independent FUV instruments: IMAGE/SI-12, TIMED/GUVI and DMSP/SSUSI. The SI-12 observations show that the dayside detached aurora (DDA) was located between 60° and 68° Mlat and between 06:00 and 15:00 MLT. It lasted for only ˜2 min. Coincident in situ Polar measurements show that sudden bursts of proton EMIC waves (˜2 min) were associated with the DDA. This provides direct evidence of the link between the EMIC waves and the DDA. The DA in the duskside and nightside appeared once the DDA disappeared. GUVI and SSUSI also observed the DA in the duskside and dayside with more details. Ring current simulations show that ˜10 keV protons with sausage-shaped spatial distribution of high anisotropy in flux and temperature were the particle source for the duskside and nightside DA. Compression of the magnetosphere appears to be the driver for both of the DDA and dusk/night DA. The nightside DA was observed for the first time during a sudden commencement. To unify the different terminologies, the detached auroras due to precipitating energetic protons from the ring current are called the ring current auroras.

  18. Aurorae. Firework in the sky. 2. upd. ed.; Polarlichter. Feuerwerk am Himmel

    Energy Technology Data Exchange (ETDEWEB)

    Pfoser, Andreas; Eklund, Tom

    2013-07-01

    Aurorae are fascinating phenomena. As aurora borealis and aurora australis occurring in the polar regions of both earth hemispheres, their incessant color and shape games put people in wonder. The meteorologist Andreas Pfoser explains the physical connections, which lead to the formation of this natural phenomenon. The link with the activity of the sun and the interaction in the earth atmosphere are explained detailedly and understandably. The fantastic recordings, presented in generous horizontal format has collected the Finnish aurora photographer Tom Eklund over a period of time of 14 years. Thereby it succeeded, to document also some events, the origin of which on our daystar were recorded by solar satellites, so that the sequence of events from the solar eruption until the aurora spectacle can be reproduced. The present 2nd edition contains new scientific findings. Additionally numerous aurora pictures were replaced by more actual photos created with modern technology.

  19. Drifting black aurorae?

    International Nuclear Information System (INIS)

    Schoute-Vanneck, H.; Scourfield, M.W.J.; Nielsen, E.

    1990-01-01

    Characteristics of eastward drifting forms, previously described in the literature as black aurorae, have been identified in low-light level TV camera data. The TV field of view was within the field of view of STARE and that of an all-sky camera. On the basis of these observations the authors propose that these auroral forms are a manifestation of folds or waves on the borders of auroral bands propagating along the dark regions between neighboring auroral bands. Conditions under which the folds or waves occur are compatible with their formation by the Kelvin-Helmholtz electrostatic instability

  20. Navigation GPS/GLONASS in the Arctic and aurora

    Directory of Open Access Journals (Sweden)

    Chernouss S. A.

    2016-12-01

    Full Text Available The correspondence of the time-spatial distribution of the radiances of the aurora oval and time-spatial changes in the parameters of the navigation satellites' signal has been shown. For this aim the experimental data on the regional and local heterogeneities of the Total Electron Content (or TEC and the data on the signal delays in the polar ionosphere have been analyzed. Using the data concerning aurora as the indicator of disturbances in the work of the GPS/GLONASS systems can give the opportunity to increase considerably the accuracy of positioning in the Arctic with the help of satellite navigation systems (SNS.

  1. Aurora laser optical system

    International Nuclear Information System (INIS)

    Hanlon, J.A.; McLeod, J.

    1987-01-01

    Aurora is the Los Alamos short-pulse high-power krypton fluoride laser system. It is primarily an end-to-end technology demonstration prototype for large-scale UV laser systems of interest for short-wavelength inertial confinement fusion (ICF) investigations. The system is designed to employ optical angular multiplexing and aerial amplification by electron-beam-driven KrF laser amplifiers to deliver to ICF targets a stack of pulses with a duration of 5 ns containing several kilojoules at a wavelength of 248 nm. A program of high-energy density plasma physics investigations is now planned, and a sophisticated target chamber was constructed. The authors describe the design of the optical system for Aurora and report its status. This optical system was designed and is being constructed in two phases. The first phase carries only through the amplifier train and does not include a target chamber or any demultiplexing. Installation should be complete, and some performance results should be available. The second phase provides demultiplexing and carries the laser light to target. The complete design is reported

  2. Detection of surface glow related to spacecraft glow phenomenon

    Energy Technology Data Exchange (ETDEWEB)

    Langer, W.D.; Cohen, S.A.; Manos, D.M.; Motley, R.W.; Ono, M.; Paul, S.; Roberts, D.; Selberg, H.

    1986-02-01

    We have developed a high flux source of low energy neutral beams to study the spacecraft glow phenomena by using a biased limiter to neutralize plasma in ACT-1. Beams of nitrogen and nitrogen-oxygen mixtures with energies of 1 to 15 eV and fluxes greater than or equal to 10/sup 14//cm/sup 2//s were directed on target surfaces consisting of Z-302 and Z-306 paints. With the nitrogen beams we successfully detected a glow due to beam-surface interactions. In addition, we discovered a volume glow effect due to beam-gas interactions which may also play a role in spacecraft glow. 11 refs., 14 figs.

  3. Aurorae in Australian Aboriginal Traditions

    Science.gov (United States)

    Hamacher, Duane W.

    2013-07-01

    Transient celestial phenomena feature prominently in the astronomical knowledge and traditions of Aboriginal Australians. In this paper, I collect accounts of the Aurora Australis from the literature regarding Aboriginal culture. Using previous studies of meteors, eclipses, and comets in Aboriginal traditions, I anticipate that the physical properties of aurora, such as their generally red colour as seen from southern Australia, will be associated with fire, death, blood, and evil spirits. The survey reveals this to be the case and also explores historical auroral events in Aboriginal cultures, aurorae in rock art, and briefly compares Aboriginal auroral traditions with other global indigenous groups, including the Maori of New Zealand.

  4. Adventures in search of auroras

    Science.gov (United States)

    Forsyth, Colin

    2016-09-01

    In her book Aurora: In Search of the Northern Lights, Melanie Windridge describes travelling around the Arctic Circle on a quest to see the biggest and best auroral displays and to understand the physics that drives them.

  5. Urochordate ascidians possess a single isoform of Aurora kinase that localizes to the midbody via TPX2 in eggs and cleavage stage embryos.

    Directory of Open Access Journals (Sweden)

    Celine Hebras

    Full Text Available Aurora kinases are key proteins found throughout the eukaryotes that control mitotic progression. Vertebrate Aurora-A and B kinases are thought to have evolved from a single Aurora-kinase isoform closest to that found in present day urochordates. In urochordate ascidians Aurora binds both TPX2 (a vertebrate AURKA partner and INCENP (a vertebrate AURKB partner and localizes to centrosomes and spindle microtubules as well as chromosomes and midbody during both meiosis and mitosis. Ascidian Aurora also displays this localization pattern during mitosis in echinoderms, strengthening the idea that non-vertebrate deuterostomes such as the urochordates and echinoderms possess a single form of Aurora kinase that has properties of vertebrate Aurora-kinase A and B. In the ascidian, TPX2 localizes to the centrosome and the spindle poles also as in vertebrates. However, we were surprised to find that TPX2 also localized strongly to the midbody in ascidian eggs and embryos. We thus examined more closely Aurora localization to the midbody by creating two separate point mutations of ascidian Aurora predicted to perturb binding to TPX2. Both forms of mutated Aurora behaved as predicted: neither localized to spindle poles where TPX2 is enriched. Interestingly, neither form of mutated Aurora localized to the midbody where TPX2 is also enriched, suggesting that ascidian Aurora midbody localization required TPX2 binding in ascidians. Functional analysis revealed that inhibition of Aurora kinase with a pharmacological inhibitor or with a dominant negative kinase dead form of Aurora caused cytokinesis failure and perturbed midbody formation during polar body extrusion. Our data support the view that vertebrate Aurora-A and B kinases evolved from a single non-vertebrate deuterostome ancestor. Moreover, since TPX2 localizes to the midbody in ascidian eggs and cleavage stage embryos it may be worthwhile re-assessing whether Aurora A kinase or TPX2 localize to the midbody

  6. The Aurora space launcher concept

    Science.gov (United States)

    Kopp, Alexander; Stappert, Sven; Mattsson, David; Olofsson, Kurt; Marklund, Erik; Kurth, Guido; Mooij, Erwin; Roorda, Evelyne

    2017-11-01

    This paper gives an overview about the Aurora reusable space launcher concept study that was initiated in late-2015/early-2016. Within the Aurora study, several spaceplane-like vehicle configurations with different geometries, propulsion systems and mission profiles will be designed, investigated and evaluated with respect to their technical and economic feasibility. The first part of this paper will discuss the study logic and the current status of the Aurora studies and introduces the first vehicle configurations and their system design status. As the identification of highly efficient structural designs is of particular interest for Aurora, the structural design and analysis approach will be discussed in higher level of detail. A special design feature of the Aurora vehicle configurations is the utilization of the novel thin-ply composite material technology for structural mass reductions. Therefore, the second part of this paper will briefly discuss this technology and investigate the application and potential mass savings on vehicle level within simplified structural analysis studies. The results indicate that significant mass savings could be possible. Finally, an outlook on the next steps is provided.

  7. The dawn of Aurora kinase research: from fly genetics to the clinic.

    Directory of Open Access Journals (Sweden)

    Mar eCarmena

    2015-11-01

    Full Text Available Aurora kinases comprise a family of highly conserved serine-threonine protein kinases that play a pivotal role in the regulation of cell cycle. Aurora kinases are not only involved in the control of multiple processes during cell division but also coordinate chromosomal and cytoskeletal events, contributing to the regulation of checkpoints and ensuring the smooth progression of the cell cycle.Because of their fundamental contribution to cell cycle regulation, Aurora kinases were originally identified in independent genetic screens designed to find genes involved in the regulation of cell division. The first aurora mutant was part of a collection of mutants isolated in C. Nusslein-Volhard’s laboratory. This collection was screened in D. M. Glover’s laboratory in search for mutations disrupting the centrosome cycle in embryos derived from homozygous mutant mothers. The mutants identified were given names related to the polar regions, and included not only aurora but also the equally famous polo. Ipl1, the only Aurora in yeast, was identified in a genetic screen looking for mutations that caused chromosome segregation defects. The discovery of a second Aurora-like kinase in mammals opened a new chapter in the research of Aurora kinases. The rat kinase AIM was found to be highly homologous to the fly and yeast proteins, but localised at the midzone and midbody and was proposed to have a role in cytokinesis. Homologs of the equatorial Aurora (Aurora B were identified in metazoans ranging from flies to humans. Xenopus Aurora B was found to be in a complex with the chromosomal passenger INCENP, and both proteins were shown to be essential in flies for chromosome structure, segregation, central spindle formation and cytokinesis. Fifteen years on, Aurora kinase research is an active field of research. After the successful introduction of the first anti-mitotic agents in cancer therapy, both Auroras have become the focus of attention as targets for

  8. Aurora status and plans

    International Nuclear Information System (INIS)

    Kristal, R.; Blair, L.S.; Burrows, M.D.

    1987-10-01

    Aurora is a short wavelength (248 nm) 10 to kJ KrF laser systems in the ICF program at Los Alamos National Laboratory. It is both an experiment in driver technology and a means for studying target performance using KrF laser light. Both features will be used to help evaluate the uv excimer laser as a viable fusion driver. The system has been designed to employ several electron-beam pumped amplifiers in series, with a final aperture of one meter square, to amplify 96 angularly mulitplexed 5 ns beamlets to the 10 kJ level. In Phase I, 48 of these beamlets are brought to target by demultiplexing and focusing with f26 optics. The beamlet ensemble, contained within an f1.9 bundle, is focused as a single beam;however, pointing is done individually. Spot size in the target plane is variable from 0.1-4 mm, with maximum averaged intensity of /similar to/ 4 x 10 15 Wcm 2 . The illumination geometry is designed specifically for several classes of important target physics experiments. These include: energy flow, symmetry and preheat studies related to indirectly driven targets;x-ray conversion and plasma coupling characterization on disc targets, and hydrodynamic instability studies in planar geometry. System integration is proceeding toward initial target experiments in /similar to/ late 1988. Ninety-six beam amplification through the penultimate amplifier has been obtained at the sub-kJ level. Installation of beam train optics is proceeding, and the target system vacuum envelope is in place. 18 refs., 12 figs., 2 tabs

  9. Image analysis of dayside aurora

    International Nuclear Information System (INIS)

    Lybekk, B.

    1989-12-01

    Ground based observations from Svalbard of the midday aurora by all sky cameras and meridian scanning photometers showed the sporadic occurrence of discrete auroral forms within or near the stable cusp or cleft aurora. Some of these forms appeared near the equatorward boundary of the stable cusp/cleft aurora and moved westward and northward. The duration of the whole event was typically less than 10 minutes. Series of such events were observed when the cusp/cleft was located at low latitudes. Satellite measurements of magnetic field and ion drift components above auroral strucures gave detailed information of auroral electrodynamics in the cusp/cleft ionosphere. Satellite observations of the dayside oval at ∼ 09 MLT showed that auroral emissions can be separated in different latitudinal zones with corresponding structures in the particle precipitation. The ground based optical instruments at Svalbard measured the stationary cleft aurora produced by soft electrons and transient discrete arcs produced by precipitating keV electrons. 89 refs

  10. The meteoric night-glow

    International Nuclear Information System (INIS)

    Baggaley, W.J.

    1977-01-01

    There exist well-documented accounts of the observations of enhanced night-glow associated with spectacular meteor shower displays. Possible mechanisms responsible for this elusive phenomenon are examined. It is shown that the observed emission is not a direct consequence of the influx of meteors on the Earth but rather has its source in scattering of solar radiation by interplanetary micrometeoroids which form the dense dustclouds ejected by the parent comets of the associated meteor streams. (author)

  11. Dissolution glow curve in LLD

    International Nuclear Information System (INIS)

    Haverkamp, U.; Wiezorek, C.; Poetter, R.

    1990-01-01

    Lyoluminescence dosimetry is based upon light emission during dissolution of previously irradiated dosimetric materials. The lyoluminescence signal is expressed in the dissolution glow curve. These curves begin, depending on the dissolution system, with a high peak followed by an exponentially decreasing intensity. System parameters that influence the graph of the dissolution glow curve, are, for example, injection speed, temperature and pH value of the solution and the design of the dissolution cell. The initial peak does not significantly correlate with the absorbed dose, it is mainly an effect of the injection. The decay of the curve consists of two exponential components: one fast and one slow. The components depend on the absorbed dose and the dosimetric materials used. In particular, the slow component correlates with the absorbed dose. In contrast to the fast component the argument of the exponential function of the slow component is independent of the dosimetric materials investigated: trehalose, glucose and mannitol. The maximum value, following the peak of the curve, and the integral light output are a measure of the absorbed dose. The reason for the different light outputs of various dosimetric materials after irradiation with the same dose is the differing solubility. The character of the dissolution glow curves is the same following irradiation with photons, electrons or neutrons. (author)

  12. Hydrogeology baseline study Aurora Mine

    International Nuclear Information System (INIS)

    1996-01-01

    A baseline hydrogeologic study was conducted in the area of Syncrude's proposed Aurora Mine in order to develop a conceptual regional hydrogeologic model for the area that could be used to understand groundwater flow conditions. Geologic information was obtained from over 2,000 coreholes and from data obtained between 1980 and 1996 regarding water level for the basal aquifer. A 3-D numerical groundwater flow model was developed to provide quantitative estimates of the potential environmental impacts of the proposed mining operations on the groundwater flow system. The information was presented in the context of a regional study area which encompassed much of the Athabasca Oil Sands Region, and a local study area which was defined by the lowlands of the Muskeg River Basin. Characteristics of the topography, hydrology, climate, geology, and hydrogeology of the region are described. The conclusion is that groundwater flow in the aquifer occurs mostly in a westerly direction beneath the Aurora Mine towards its inferred discharge location along the Athabasca River. Baseflow in the Muskeg River is mostly related to discharge from shallow surficial aquifers. Water in the river under baseflow conditions was fresh, of calcium-carbonate type, with very little indication of mineralization associated with deeper groundwater in the Aurora Mine area. 44 refs., 5 tabs., 31 figs

  13. Morphologies of omega band auroras

    Science.gov (United States)

    Sato, Natsuo; Yukimatu, Akira Sessai; Tanaka, Yoshimasa; Hori, Tomoaki

    2017-08-01

    We examined the morphological signatures of 315 omega band aurora events observed using the Time History of Events and Macroscale Interactions during Substorm ground-based all-sky imager network over a period of 8 years. We find that omega bands can be classified into the following three subtypes: (1) classical (O-type) omega bands, (2) torch or tongue (T-type) omega bands, and (3) combinations of classical and torch or tongue (O/T-type) omega bands. The statistical results show that T-type bands occur the most frequently (45%), followed by O/T-type bands (35%) and O-type bands (18%). We also examined the morphologies of the omega bands during their formation, from the growth period to the declining period through the maximum period. Interestingly, the omega bands are not stable, but rather exhibit dynamic changes in shape, intensity, and motion. They grow from small-scale bumps (seeds) at the poleward boundary of preexisting east-west-aligned auroras, rather than via the rotation or shear motion of preexisting east-west-aligned auroras, and do not exhibit any shear motion during the periods of auroral activity growth. Furthermore, the auroral luminosity is observed to increase during the declining period, and the total time from the start of the growth period to the end of the declining period is found to be about 20 min. Such dynamical signatures may be important in determining the mechanism responsible for omega band formation.

  14. Significance of Aurora B overexpression in hepatocellular carcinoma. Aurora B Overexpression in HCC

    International Nuclear Information System (INIS)

    Lin, Zhong-Zhe; Jeng, Yung-Ming; Hu, Fu-Chang; Pan, Hung-Wei; Tsao, Hsin-Wei; Lai, Po-Lin; Lee, Po-Huang; Cheng, Ann-Lii; Hsu, Hey-Chi

    2010-01-01

    To investigate the significance of Aurora B expression in hepatocellular carcinoma (HCC). The Aurora B and Aurora A mRNA level was measured in 160 HCCs and the paired nontumorous liver tissues by reverse transcription-polymerase chain reaction. Mutations of the p53 and β-catenin genes were analyzed in 134 and 150 tumors, respectively, by direct sequencing of exon 2 to exon 11 of p53 and exon 3 of β-catenin. Anticancer effects of AZD1152-HQPA, an Aurora B kinase selective inhibitor, were examined in Huh-7 and Hep3B cell lines. Aurora B was overexpressed in 98 (61%) of 160 HCCs and in all 7 HCC cell lines examined. The overexpression of Aurora B was associated with Aurora A overexpression (P = 0.0003) and p53 mutation (P = 0.002) and was inversely associated with β-catenin mutation (P = 0.002). Aurora B overexpression correlated with worse clinicopathologic characteristics. Multivariate analysis confirmed that Aurora B overexpression was an independent poor prognostic factor, despite its interaction with Aurora A overexpression and mutations of p53 and β-catenin. In Huh-7 and Hep3B cells, AZD1152-HQPA induced proliferation blockade, histone H3 (Ser10) dephosphorylation, cell cycle disturbance, and apoptosis. Aurora B overexpression is an independent molecular marker predicting tumor invasiveness and poor prognosis of HCC. Aurora B kinase selective inhibitors are potential therapeutic agents for HCC treatment

  15. Aurora europe's space exploration programme

    Science.gov (United States)

    Ongaro, F.; Swings, J. P.; Condessa, R.

    2003-04-01

    What will happen after the ISS in terms of space exploration, specifically to the human presence beyond Earth? What will be the role of Europe in the future international venture to explore space? What are the most immediate actions to be undertaken in Europe in order to best profit from the efforts made through the participation in the ISS and to position Europe's capabilities according to its interests? As approved by the Ministers at the Edinburgh Council in November 2001, the European Space Exploration Programme - Aurora - is ESA's programme in charge of defining and implementing the long term plan for human and robotic exploration of the Solar system. The Aurora programme started in 2002 and extends until the end goal of Aurora: the first human mission to Mars, expected in the 2025-2030 time-frame. The approach of Aurora is to implement a robust development of technologies and robotic missions, in parallel to the utilization phase of the ISS, to prepare for a continuous and sustainable future of human space exploration (which shall include the Moon, Mars and the asteroids as targets), in which Europe will be a valuable partner. Two classes of missions are foreseen in the programme's strategy: Flagships, defined as major missions driving to soft landing, in-situ analysis, sample return from other planetary bodies and eventually human missions; and Arrows, defined as cost-capped, short development time missions to demonstrate new technologies or mission approaches, or to exploit opportunities for payloads on European or international missions. So far the participating national delegations have approved two Flagships (ExoMars and Mars Sample Return) and two Arrows (Earth Re-entry and Mars Aerocapture) for phase A industrial studies. Although the last call for ideas of Aurora resulted in the definition of two Flagship missions targeted to Mars, the next one might be aimed to the Moon. At this stage the role of the Moon, on the path of Mars exploration is not

  16. Numerical analysis of thermoluminescence glow curves

    International Nuclear Information System (INIS)

    Gomez Ros, J. M.; Delgado, A.

    1989-01-01

    This report presents a method for the numerical analysis of complex thermoluminescence glow curves resolving the individual glow peak components. The method employs first order kinetics analytical expressions and is based In a Marquart-Levenberg minimization procedure. A simplified version of this method for thermoluminescence dosimetry (TLD) is also described and specifically developed to operate whit Lithium Fluoride TLD-100. (Author). 36 refs

  17. Glow Sticks: Spectra and Color Mixing

    Science.gov (United States)

    Birriel, Jennifer; Birriel, Ignacio

    2014-01-01

    Glow sticks are a popular Halloween staple familiar to most of our students. The production of light via a chemical reaction is called "chemiluminescence," and glow sticks are often used as demonstrations and experiments in the chemistry classroom to study reaction rates as a function of temperature. A black light can be used to…

  18. Glow discharge in singlet oxygen

    International Nuclear Information System (INIS)

    Vagin, N.P.; Ionin, A.A.; Klimachev, Yu.M.; Sinitsyn, D.V.; Yuryshev, N.N.; Kochetov, I.V.; Napartovich, A.P.

    2003-01-01

    Currently, there is no experimental data on the plasma balance in gas mixtures with a high content of singlet delta oxygen O 2 ( 1 Δ g ). These data can be obtained by studying the parameters of an electric discharge in singlet oxygen produced by a chemical generator. The O 2 ( 1 Δ g ) molecules significantly change the kinetics of electrons and negative ions in plasma. Hence, the discharge conditions at low and high O 2 ( 1 Δ g ) concentrations are very different. Here, the parameters of the positive column of a glow discharge in a gas flow from a chemical singlet-oxygen generator are studied. It is experimentally shown that, at an O 2 ( 1 Δ g ) concentration of 50% and at pressures of 1.5 and 2 torr, the electric field required to sustain the discharge is considerably lower than in the case when all of the oxygen molecules are in the ground state. A theoretical model of the glow discharge is proposed whose predictions are in good agreement with the experimental data

  19. Atmospheric sampling glow discharge ionization source

    Science.gov (United States)

    McLuckey, S.A.; Glish, G.L.

    1989-07-18

    An atmospheric sampling glow discharge ionization source that can be used in combination with an analytical instrument which operates at high vacuum, such as a mass spectrometer. The atmospheric sampling glow discharge ionization source comprises a chamber with at least one pair of electrodes disposed therein, an inlet for a gaseous sample to be analyzed and an outlet communicating with an analyzer which operates at subatmospheric pressure. The ionization chamber is maintained at a pressure below atmospheric pressure, and a voltage difference is applied across the electrodes to induce a glow discharge between the electrodes, so that molecules passing through the inlet are ionized by the glow discharge and directed into the analyzer. The ionization source accepts the sample under atmospheric pressure conditions and processes it directly into the high vacuum instrument, bridging the pressure gap and drawing off unwanted atmospheric gases. The invention also includes a method for analyzing a gaseous sample using the glow discharge ionization source described above. 3 figs.

  20. Generation of proton aurora by magnetosonic waves.

    Science.gov (United States)

    Xiao, Fuliang; Zong, Qiugang; Wang, Yongfu; He, Zhaoguo; Su, Zhenpeng; Yang, Chang; Zhou, Qinghua

    2014-06-05

    Earth's proton aurora occurs over a broad MLT region and is produced by the precipitation of low-energy (2-10 keV) plasmasheet protons. Proton precipitation can alter chemical compositions of the atmosphere, linking solar activity with global climate variability. Previous studies proposed that electromagnetic ion cyclotron waves can resonate with protons, producing proton scattering precipitation. A long-outstanding question still remains whether there is another mechanism responsible for the proton aurora. Here, by performing satellite data analysis and diffusion equation calculations, we show that fast magnetosonic waves can produce trapped proton scattering that yields proton aurora. This provides a new insight into the mechanism of proton aurora. Furthermore, a ray-tracing study demonstrates that magnetosonic wave propagates over a broad MLT region, consistent with the global distribution of proton aurora.

  1. Double layers above the aurora

    International Nuclear Information System (INIS)

    Temerin, M.; Mozer, F.S.

    1987-01-01

    Two different kinds of double layers were found in association with auroral precipitation. One of these is the so-called electrostatic shock, which is oriented at an oblique angle to the magnetic field in such a way that the perpendicular electric field is much larger than the parallel electric field. This type of double layer is often found at the edges of regions of upflowing ion beams and the direction of the electric fields in the shock points toward the ion beam. The potential drop through the shock can be several kV and is comparable to the total potential needed to produce auroral acceleration. Instabilities associated with the shock may generate obliquely propagating Alfven waves, which may accelerate electrons to produce flickering auroras. The flickering aurora provides evidence that the electrostatic shock may have large temporal fluctuations. The other kind of double layer is the small-amplitude double layer found in regions of upward flowing in beams, often in association with electrostatic ion cyclotron waves. The parallel and perpendicular electric fields in these structures are comparable in magnitude. The associated potentials are a few eV. Since many such double layers are found in regions of upward flowing ion beams, the combined potential drop through a set of these double layers can be substantial

  2. Nature's Fireworks: The Inner Workings of the Auroras.

    Science.gov (United States)

    Kikoyin, A. K.

    1992-01-01

    Describes the great variety of observations surrounding the auroras (both borealis and australis), and provides photographs from the space shuttle, Discovery. Discusses where and when the auroras can be observed, the process that the Earth's magnetic phenomena fulfill in how and why auroras appear, and the effects of solar wind upon auroras. (JJK)

  3. Signatures in the dayside aurora of plasma transfer from the magnetosheath

    International Nuclear Information System (INIS)

    Sandholt, P.E; Deehr, C.S; Egeland, A.; Lybekk, B.; Viereck, R.; Romick, G.J.

    1986-02-01

    Continuous ground-based observations of the dayside aurora provide important information, complementary to the in situ measurements from satellites, on plasma transport and electromagnetic coupling between the magnetosheath and the magnetosphere. In this study observations of the polar cusp/dayside oval aurora from Svalbard,Norway, simultaneous observations of the nightside aurora from Poker Flat, Alaska, and the interplanetary magnetic field from satellites, are used to identify the ionospheric signatures of plasma transfer from the solar wind to the magnetosphere. The characteristics of motion, spatial scale, time of duration and repetition frequency of certain dayside auroral forms which occur at the time of large-scale oval expansions (IMF Bsub(z) < 0), are observed to be consistent with the expected optical signatures of plasma transfer through the dayside magnetopause boundary layer, in association with flux transfer events. Similarly, more large-scale (time and space) events are tentatively explained by the quasi steady-state reconnection process

  4. Control of centrin stability by Aurora A.

    Directory of Open Access Journals (Sweden)

    Kara B Lukasiewicz

    Full Text Available Aurora A is an oncogenic serine/threonine kinase which can cause cell transformation and centrosome amplification when over-expressed. Human breast tumors show excess Aurora A and phospho-centrin in amplified centrosomes. Here, we show that Aurora A mediates the phosphorylation of and localizes with centrin at the centrosome, with both proteins reaching maximum abundance from prophase through metaphase, followed by their precipitous loss in late stages of mitosis. Over-expression of Aurora A results in excess phospho-centrin and centrosome amplification. In contrast, centrosome amplification is not seen in cells over-expressing Aurora A in the presence of a recombinant centrin mutant lacking the serine phosphorylation site at residue 170. Expression of a kinase dead Aurora A results in a decrease in mitotic index and abrogation of centrin phosphorylation. Finally, a recombinant centrin mutation that mimics centrin phosphorylation increases centrin's stability against APC/C-mediated proteasomal degradation. Taken together, these results suggest that the stability of centrin is regulated in part by Aurora A, and that excess phosphorylated centrin may promote centrosome amplification in cancer.

  5. Is the negative glow plasma of a direct current glow discharge negatively charged?

    Energy Technology Data Exchange (ETDEWEB)

    Bogdanov, E. A.; Saifutdinov, A. I. [Faculty of Physics, St. Petersburg State University, 198504 St. Petersburg (Russian Federation); Demidov, V. I., E-mail: Vladimir.Demidov@mail.wvu.edu [Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506 (United States); Kudryavtsev, A. A. [Faculty of Physics, St. Petersburg State University, 198504 St. Petersburg (Russian Federation); ITMO University, Kronverkskiy pr. 49, 197101 St. Petersburg (Russian Federation)

    2015-02-15

    A classic problem in gas discharge physics is discussed: what is the sign of charge density in the negative glow region of a glow discharge? It is shown that traditional interpretations in text-books on gas discharge physics that states a negative charge of the negative glow plasma are based on analogies with a simple one-dimensional model of discharge. Because the real glow discharges with a positive column are always two-dimensional, the transversal (radial) term in divergence with the electric field can provide a non-monotonic axial profile of charge density in the plasma, while maintaining a positive sign. The numerical calculation of glow discharge is presented, showing a positive space charge in the negative glow under conditions, where a one-dimensional model of the discharge would predict a negative space charge.

  6. Determining the mechanism of cusp proton aurora.

    Science.gov (United States)

    Xiao, Fuliang; Zong, Qiugang; Su, Zhenpeng; Yang, Chang; He, Zhaoguo; Wang, Yongfu; Gao, Zhonglei

    2013-01-01

    Earth's cusp proton aurora occurs near the prenoon and is primarily produced by the precipitation of solar energetic (2-10 keV) protons. Cusp auroral precipitation provides a direct source of energy for the high-latitude dayside upper atmosphere, contributing to chemical composition change and global climate variability. Previous studies have indicated that magnetic reconnection allows solar energetic protons to cross the magnetopause and enter the cusp region, producing cusp auroral precipitation. However, energetic protons are easily trapped in the cusp region due to a minimum magnetic field existing there. Hence, the mechanism of cusp proton aurora has remained a significant challenge for tens of years. Based on the satellite data and calculations of diffusion equation, we demonstrate that EMIC waves can yield the trapped proton scattering that causes cusp proton aurora. This moves forward a step toward identifying the generation mechanism of cusp proton aurora.

  7. The thermoluminescence glow-curve analysis using GlowFit - the new powerful tool for deconvolution

    International Nuclear Information System (INIS)

    Puchalska, M.; Bilski, P.

    2005-10-01

    A new computer program, GlowFit, for deconvoluting first-order kinetics thermoluminescence (TL) glow-curves has been developed. A non-linear function describing a single glow-peak is fitted to experimental points using the least squares Levenberg-Marquardt method. The main advantage of GlowFit is in its ability to resolve complex TL glow-curves consisting of strongly overlapping peaks, such as those observed in heavily doped LiF:Mg,Ti (MTT) detectors. This resolution is achieved mainly by setting constraints or by fixing selected parameters. The initial values of the fitted parameters are placed in the so-called pattern files. GlowFit is a Microsoft Windows-operated user-friendly program. Its graphic interface enables easy intuitive manipulation of glow-peaks, at the initial stage (parameter initialization) and at the final stage (manual adjustment) of fitting peak parameters to the glow-curves. The program is freely downloadable from the web site www.ifj.edu.pl/NPP/deconvolution.htm (author)

  8. Hubble Images Reveal Jupiter's Auroras

    Science.gov (United States)

    1996-01-01

    These images, taken by the Hubble Space Telescope, reveal changes in Jupiter's auroral emissions and how small auroral spots just outside the emission rings are linked to the planet's volcanic moon, Io. The images represent the most sensitive and sharply-detailed views ever taken of Jovian auroras.The top panel pinpoints the effects of emissions from Io, which is about the size of Earth's moon. The black-and-white image on the left, taken in visible light, shows how Io and Jupiter are linked by an invisible electrical current of charged particles called a 'flux tube.' The particles - ejected from Io (the bright spot on Jupiter's right) by volcanic eruptions - flow along Jupiter's magnetic field lines, which thread through Io, to the planet's north and south magnetic poles. This image also shows the belts of clouds surrounding Jupiter as well as the Great Red Spot.The black-and-white image on the right, taken in ultraviolet light about 15 minutes later, shows Jupiter's auroral emissions at the north and south poles. Just outside these emissions are the auroral spots. Called 'footprints,' the spots are created when the particles in Io's 'flux tube' reach Jupiter's upper atmosphere and interact with hydrogen gas, making it fluoresce. In this image, Io is not observable because it is faint in the ultraviolet.The two ultraviolet images at the bottom of the picture show how the auroral emissions change in brightness and structure as Jupiter rotates. These false-color images also reveal how the magnetic field is offset from Jupiter's spin axis by 10 to 15 degrees. In the right image, the north auroral emission is rising over the left limb; the south auroral oval is beginning to set. The image on the left, obtained on a different date, shows a full view of the north aurora, with a strong emission inside the main auroral oval.The images were taken by the telescope's Wide Field and Planetary Camera 2 between May 1994 and September 1995.This image and other images and data

  9. Aurora kinases in childhood acute leukemia: the promise of aurora B as therapeutic target

    Science.gov (United States)

    Hartsink-Segers, S A; Zwaan, C M; Exalto, C; Luijendijk, M W J; Calvert, V S; Petricoin, E F; Evans, W E; Reinhardt, D; de Haas, V; Hedtjärn, M; Hansen, B R; Koch, T; Caron, H N; Pieters, R; Den Boer, M L

    2013-01-01

    We investigated the effects of targeting the mitotic regulators aurora kinase A and B in pediatric acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). Aurora protein expression levels in pediatric ALL and AML patient samples were determined by western blot and reverse phase protein array. Both kinases were overexpressed in ALL and AML patients (PE2A-PBX1-translocated ALL cases (PE2A-PBX1-positive cases, were sensitive as well. In adult AML early clinical trials, clear responses are observed with barasertib. Here we show that inhibition of aurora B, more than aurora A, has an antiproliferative and pro-apoptotic effect on acute leukemia cells, indicating that particularly targeting aurora B may offer a new strategy to treat pediatric ALL and AML. PMID:22940834

  10. A Terrella Device for Simulating Aurora-Like Phenomena in a Box

    Science.gov (United States)

    Messerotti, M.; Baccomi, R.; Iugovaz, D.; Lilensten, J.

    2009-04-01

    A Terrella device was developed and setup in Trieste in 2006 to be used as an experimental training device during practicum sessions of the Advanced International School on Space Weather at ICTP. The Terrella consisted of a vacuum chamber, where an aluminum sphere with an embedded permanent magnet bar mimics the Earth (Terrella) and its magnetic field, and a system of electrodes is set to a high potential difference to generate an electron flow (particle wind) that ionizes the residual air around the sphere. This results in aurora-like glowing patterns whose geometry is dependent on the orientation and distance of the bar magnet, so that various configurations can be experimented. This Terrella device proved to be an effective tool not only for academic but also for outreach purposes. We will briefly present both applications, focusing in particular on the latter, and on the planned use for IHY EPO activities.

  11. The Glowing Pickle and Other Vegetables

    Directory of Open Access Journals (Sweden)

    Ryan Burns

    2009-06-01

    Full Text Available The phenomenon known as the glowing pickle was investigated. Voltages ranging from 80-140 Volts AC were placed across a variety of vegetable specimens, both fresh and soaked in several salt solutions. The glowing was caused by electric arcing across a steam-filled cavity in the specimen. The emission spectra showed lines indicating the presence of potassium and sodium ions in the fresh specimens. In the specimens soaked in salt solutions, emission spectra matching the salt ions were observed.

  12. Generation of uniform atmospheric pressure argon glow plasma by ...

    Indian Academy of Sciences (India)

    In this paper, atmospheric pressure glow discharges (APGD) in argon generated in parallel plate dielectric barrier discharge ... Keywords. Atmospheric pressure glow discharge; argon glow discharge; electron density; hydrophobicity. PACS No. ... alcohol for 10 min and then dried in air. The effect of the treatment time on the ...

  13. Jung's quest for the "Aurora consurgens"

    DEFF Research Database (Denmark)

    Haaning, Aksel

    2014-01-01

    the Mysterium Conuinctionis more than twenty years later. It is further maintained that this choice of the Aurora is a profound expression of Jung's ambition to revitalize the past from within the individual, and helps explain Jung's deep concern with the welfare and future of modern society....

  14. Proyecto Aurora: Building a Community of Women.

    Science.gov (United States)

    Noya, Gladys R. Capella

    1997-01-01

    Describes the development of Proyecto Aurora, a program to develop and implement educational, support, and research programs to benefit low-income women in Puerto Rico. Portraits of some clients illustrate the rewards and challenges of working with this community and furthering their educational experiences and opportunities. (SLD)

  15. Aurora Mine project - historical resources baseline study

    International Nuclear Information System (INIS)

    Reeves, B.

    1996-01-01

    This volume contains the results of a base line archaeological study of the Aurora Mine Project local study area. It was compiled in support of Syncrude Canada's application to the Alberta Energy and Utilities Board (AEUB) and Alberta Environmental Protection to construct and operate it new Aurora Mine, located northeast of Fort McMurray, Alberta. The objective of this study was to compile, consolidate, review and analyze the reports for the area compiled over the past 22 years in and adjacent to the local study area (LSA), particularly those of now existing and Syncrude projects, and previously proposed Alsands and OSLO projects. The report is a summary of the human history in the area including pre-contact native archaeological sites, past archaeological studies, the Hinterland site pattern, post-contact native traditional sites, oil sands exploration/development related sites and paleontological sites in the subject area, and areas adjacent to it. 150 refs., 5 tabs., 43 figs

  16. Aurora kinase inhibitors: Progress towards the clinic

    Czech Academy of Sciences Publication Activity Database

    Kollareddy, M.; Zheleva, D.; Dzubak, P.; Brahmkshatriya, Pathik; Lepšík, Martin; Hajduch, M.

    2012-01-01

    Roč. 30, č. 6 (2012), s. 2411-2432 ISSN 0167-6997 Grant - others:GA ČR(CZ) GA301/08/1649; GA ČR(CZ) GD303/09/H048 Program:GA; GD Institutional research plan: CEZ:AV0Z40550506 Keywords : Aurora kinases * cancer * inhibitors Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.498, year: 2012

  17. Aurora A's functions during mitotic exit: the Guess Who game

    Directory of Open Access Journals (Sweden)

    David eReboutier

    2015-12-01

    Full Text Available Until recently, the knowledge of Aurora A kinase functions during mitosis was limited to pre-metaphase events, particularly centrosome maturation, G2/M transition, and mitotic spindle assembly. However, an involvement of Aurora A in post-metaphase events was also suspected, but not clearly demonstrated due to the technical difficulty to perform the appropriate experiments. Recent developments of both an analog specific version of Aurora A, and of small molecule inhibitors have led to the first demonstration that Aurora A is required for the early steps of cytokinesis. As in pre-metaphase, Aurora A plays diverse functions during anaphase, essentially participating in astral microtubules dynamics and central spindle assembly and functioning. The present review describes the experimental systems used to decipher new functions of Aurora A during late mitosis and situate these functions into the context of cytokinesis mechanisms.

  18. Exploring the Secrets of the Aurora

    Science.gov (United States)

    Siscoe, George

    Short, professional autobiographies of the founders of space physics have been solicited by AGU's History Committee and published in special sections of Space Physics issues of the Journal of Geophysical Research. Here we have a book-length professional autobiography by the discoverer of magnetospheric substorms, which is arguably the most intensely researched topic in the field.Probably the book's most valuable contribution to the history of space physics is precisely the narration of the discovery of substorms. Exploring the Secrets of the Aurora has an epic quality. It starts with Akasofu's insight that the auroral zone—a circumpolar zone that auroras inhabit, with geographic borders established in the previous century—is a fiction. There followed a struggle to replace it with the concept of an expandable auroral oval, which has quite a different shape. The road to final success entailed Akasofu's installing a chain of aurora-imaging, “all-sky” cameras stretching the north-south length of Alaska. These proved the point and set a precedent for north-south aligned magnetometer chains.

  19. Aurora Research: Earth/Space Data Fusion Powered by GIS and Python

    Science.gov (United States)

    Kalb, V. L.; Collado-Vega, Y. M.; MacDonald, E.; Kosar, B.

    2017-12-01

    The Aurora Borealis and Australis Borealis are visually spectacular, but are also an indicator of Sun-magnetosphere-ionosphere energy transfer during geomagnetic storms. The Saint Patrick's Day Storm of 2015 is a stellar example of this, and is the focus of our study that utilizes the Geographical Information Services of ArcGIS to bring together diverse and cross disciplinary data for analysis. This research leverages data from a polar-orbiting Earth science sensor band that is exquisitely sensitive to visible light, namely the Day/Night Band (DNB) of the VIIRS instrument onboard the Suomi NPP satellite. This Sun-synchronous data source can provide high temporal and spatial resolution observations of the aurorae, which is not possible with current space science instruments. This data can be compared with auroral model data, solar wind measurements, and citizen science data of aurora observations and tweets. While the proposed data sources are diverse in type and format, their common attribute is location. This is exploited by bringing all the data into ArcGIS for mapping and analysis. The Python programming language is used extensively to automate the data preprocessing, group the DNB and citizen science observations to temporal windows associated with an auroral model timestep, and print the data to a pdf mapbook for sharing with team members. There are several goals for this study: compare the auroral model predictions with DNB data, look for fine-grained structure of the aurora in the DNB data, compare citizen science data with DNB values, and correlate DNB intensity with solar wind data. This study demonstrates the benefits of using a GIS platform to bring together data that is diverse in type and format for scientific exploration, and shows how Python can be used to scale up to large datasets.

  20. Magnetospheric source region of discrete auroras inferred from their relationship with isotropy boundaries of energetic particles

    Directory of Open Access Journals (Sweden)

    A. G. Yahnin

    1997-08-01

    Full Text Available According to observations, the discrete auroral arcs can sometimes be found, either deep inside the auroral oval or at the poleward border of the wide (so-called double auroral oval, which map to very different regions of the magnetotail. To find common physical conditions for the auroral-arc generation in these magnetotail regions, we study the spatial relationship between the diffuse and discrete auroras and the isotropic boundaries (IBs of the precipitating energetic particles which can be used to characterise locally the equatorial magnetic field in the tail. From comparison of ground observation of auroral forms with meridional profiles of particle flux measured simultaneously by the low-altitude NOAA satellites above the ground observation region, we found that (1 discrete auroral arcs are always situated polewards from (or very close to the IB of >30-keV electrons, whereas (2 the IB of the >30-keV protons is often seen inside the diffuse aurora. These relationships hold true for both quiet and active (substorm conditions in the premidnight-nightside (18-01-h MLT sector considered. In some events the auroral arcs occupy a wide latitudinal range. The most equatorial of these arcs was found at the poleward edge of the diffuse auroras (but anyway in the vicinity of the electron IB, the most poleward arcs were simultaneously observed on the closed field lines near the polar-cap boundary. These observations disagree with the notion that the discrete aurora originate exclusively in the near-Earth portion of plasma sheet or exclusively on the PSBL field lines. Result (1 may imply a fundamental feature of auroral-arc formation: they originate in the current-sheet regions having very curved and tailward-stretched magnetic field lines.

  1. Possible Cause of Extremely Bright Aurora Witnessed in East Asia on 17 September 1770

    Science.gov (United States)

    Ebihara, Yusuke; Hayakawa, Hisashi; Iwahashi, Kiyomi; Tamazawa, Harufumi; Kawamura, Akito Davis; Isobe, Hiroaki

    2017-10-01

    Extremely bright aurora was witnessed in East Asia on 17 September 1770, according to historical documents. The aurora was described as "as bright as a night with full moon" at magnetic latitude of 25°. The aurora was dominated by red color extending from near the horizon up beyond the polar star (corresponding to elevation angle of 35°). We performed a two-stream electron transport code to calculate the volume emission rates at 557.7 nm (OI) and 630.0 nm (OI). Two types of distribution of precipitating electrons were assumed. The first one is based on the unusually intense electron flux measured by the DMSP satellite in the March 1989 storm. The distribution consists of hot (peaking at 3 keV) and cold (peaking at 71 eV) components. The second one is the same as the first one, but the hot component is removed. We call this high-intensity low-energy electrons (HILEEs). The first spectrum results in an auroral display with a bright, lower green border. The second one results in red-dominated aurora extending up to the elevation angle of 35° when the equatorward boundary of the electron precipitation is located at 32° invariant latitude. The poleward boundary of the precipitation would be 42° invariant latitude or greater to explain the auroral display extending from near the horizon. The origin of the HILEEs is probably the plasma sheet or the plasmasphere that is transported earthward to L 1.39 due to enhanced magnetospheric convection. Local heating or acceleration is also plausible.

  2. Preclinical validation of Aurora kinases-targeting drugs in osteosarcoma

    NARCIS (Netherlands)

    Tavanti, E.; Sero, V.; Vella, S.; Fanelli, M.; Michelacci, F.; Landuzzi, L.; Magagnoli, G.; Versteeg, R.; Picci, P.; Hattinger, C. M.; Serra, M.

    2013-01-01

    Aurora kinases are key regulators of cell cycle and represent new promising therapeutic targets in several human tumours. Biological relevance of Aurora kinase-A and -B was assessed on osteosarcoma clinical samples and by silencing these genes with specific siRNA in three human osteosarcoma cell

  3. Preliminary studies of the helminth parasites of Limicolaria Aurora in ...

    African Journals Online (AJOL)

    Specimens of Limicolaria aurora collected from Ile-Ife area were surveyed for infection with parasitic helminthes. The snails were picked from bushes and dissected and examined in the laboratory. Four different helminth parasites comprising of 3 nematodes and a digenetic trematode were observed in L. aurora.

  4. Achieving ultrahigh vacuum in an unbaked chamber with glow ...

    Indian Academy of Sciences (India)

    2016-12-06

    Dec 6, 2016 ... nected in series through a load resistor of 100 to the SS anode and the vacuum chamber. The vacuum chamber was grounded electrically so that it will act as cathode for the glow discharge. A 35 CF glass window was provided to continuously monitor the glow during experiment. Double Langmuir probe ...

  5. A photometric model for predicting the sky glow of greenhouses

    NARCIS (Netherlands)

    Alferdinck, J.W.A.M.; Janssen, E.G.O.N.; Zonneveldt, L.; Ruigrok, J.

    2006-01-01

    many greenhouses use artificial light to grow plants. Part of this light escapes, scatters in the sky and causes sky glow. Residents in the vicinity complain about the absence of natural darkness. A light scatter model is developed in order to quantify the dose of the sky glow. The luminance of the

  6. Thermoluminescence glow curve involving any extent of retrapping ...

    Indian Academy of Sciences (India)

    the occurrence of TL glow curve [3]. Mechanisms inherent in systems involving first- order kinetics or monomolecular kinetics are supposed to be recombination dominant with negligible or zero retrapping. Intensity (I1) of the TL glow curve at the temperature. T involving first-order kinetics is represented by [4]. I1 = n0s1 exp.

  7. Jovian-like aurorae on Saturn.

    Science.gov (United States)

    Stallard, Tom; Miller, Steve; Melin, Henrik; Lystrup, Makenzie; Cowley, Stan W H; Bunce, Emma J; Achilleos, Nicholas; Dougherty, Michele

    2008-06-19

    Planetary aurorae are formed by energetic charged particles streaming along the planet's magnetic field lines into the upper atmosphere from the surrounding space environment. Earth's main auroral oval is formed through interactions with the solar wind, whereas that at Jupiter is formed through interactions with plasma from the moon Io inside its magnetic field (although other processes form aurorae at both planets). At Saturn, only the main auroral oval has previously been observed and there remains much debate over its origin. Here we report the discovery of a secondary oval at Saturn that is approximately 25 per cent as bright as the main oval, and we show this to be caused by interaction with the middle magnetosphere around the planet. This is a weak equivalent of Jupiter's main oval, its relative dimness being due to the lack of as large a source of ions as Jupiter's volcanic moon Io. This result suggests that differences seen in the auroral emissions from Saturn and Jupiter are due to scaling differences in the conditions at each of these two planets, whereas the underlying formation processes are the same.

  8. Atmospheric Pressure Glow Discharge with Liquid Electrode

    Science.gov (United States)

    Tochikubo, Fumiyoshi

    2013-09-01

    Nonthermal atmospheric pressure plasmas in contact with liquid are widely studied aiming variety of plasma applications. DC glow discharge with liquid electrode is an easy method to obtain simple and stable plasma-liquid interface. When we focus attention on liquid-phase reaction, the discharge system is considered as electrolysis with plasma electrode. The plasma electrode will supply electrons and positive ions to the liquid surface in a different way from the conventional metal electrode. However, the phenomena at plasma-liquid interface have not been understood well. In this work, we studied physical and chemical effect in liquid induced by dc atmospheric pressure glow discharge with liquid electrode. The experiment was carried out using H-shaped Hoffman electrolysis apparatus filled with electrolyte, to separate the anodic and cathodic reactions. Two nozzle electrodes made of stainless steel are set about 2 mm above the liquid surface. By applying a dc voltage between the nozzle electrodes, dc glow discharges as plasma electrodes are generated in contact with liquid. As electrolyte, we used aqueous solutions of NaCl, Na2SO4, AgNO3 and HAuCl4. AgNO3 and HAuCl4 are to discuss the reduction process of metal ions for synthesis of nanoparticles (NPs). OH radical generation yield in liquid was measured by chemical probe method using terephthalic acid. Discharge-induced liquid flow was visualized by Schlieren method. Electron irradiation to liquid surface (plasma cathode) generated OH- and OH radical in liquid while positive ion irradiation (plasma anode) generated H+ and OH radical. The generation efficiency of OH radical was better with plasma anode. Both Ag NPs in AgNO3 and Au NPs in HAuCl4 were synthesized with plasma cathode while only Au NPs were generated with plasma anode. Possible reaction process is qualitatively discussed. The discharge-induced liquid flow such as convection pattern was strongly influenced by the gas flow on the liquid surface. This work

  9. Probiotic bacteria induce a 'glow of health'.

    Directory of Open Access Journals (Sweden)

    Tatiana Levkovich

    Full Text Available Radiant skin and hair are universally recognized as indications of good health. However, this 'glow of health' display remains poorly understood. We found that feeding of probiotic bacteria to aged mice induced integumentary changes mimicking peak health and reproductive fitness characteristic of much younger animals. Eating probiotic yogurt triggered epithelial follicular anagen-phase shift with sebocytogenesis resulting in thick lustrous fur due to a bacteria-triggered interleukin-10-dependent mechanism. Aged male animals eating probiotics exhibited increased subcuticular folliculogenesis, when compared with matched controls, yielding luxuriant fur only in probiotic-fed subjects. Female animals displayed probiotic-induced hyperacidity coinciding with shinier hair, a feature that also aligns with fertility in human females. Together these data provide insights into mammalian evolution and novel strategies for integumentary health.

  10. TPX2 Protein of Arabidopsis Activates Aurora Kinase 1, But Not Aurora Kinase 3 In Vitro

    Czech Academy of Sciences Publication Activity Database

    Tomaštíková, Eva; Demidov, D.; Jeřábková, Hana; Binarová, Pavla; Houben, A.; Doležel, Jaroslav; Petrovská, Beáta

    2015-01-01

    Roč. 33, č. 6 (2015), s. 1988-1995 ISSN 0735-9640 R&D Projects: GA ČR(CZ) GA14-28443S; GA MŠk(CZ) LO1204; GA ČR GAP501/12/2333 Institutional support: RVO:61389030 ; RVO:61388971 Keywords : Aurora kinase * Targeting protein for Xklp2 * In vitro kinase assay Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.304, year: 2015

  11. Construction Of RF Power Supply For Glow Discharge Plasma

    International Nuclear Information System (INIS)

    Yunanto; Wibowo, Tono; Wirjoadi; Suryadi

    1996-01-01

    A RF power supply for glow discharge plasma has been made, so that on glow discharge reactor appear plasma that can be used make excellent matter. The device consisted of oscillator with LC tank circuit method, RF voltage amplifier, RF power amplifier and matching box. The device can be operated at 4 MHz to 13,56 MHz with optimum power output 30 watt. The RF power supply was coupled through matching box with glow discharge tube of capacitive method and working properly during 8 hours operation. The plasma stabilization has been tested and shows that stabilizations is about 2 x 10 - 2 / hour

  12. Multiplicity detector using a glow-discharge memory

    International Nuclear Information System (INIS)

    Mulera, T.; Elola, M.; Perez-Mendez, V.; Wiedenbeck, P.

    1981-04-01

    It has been proposed to eliminate the x-y cor relation ambiguities introduced by multiple tracks in a wire chamber by using the chamber itself as a memory. Hits in the chamber itself ignite glow discharges storing the x-y location of the hits in a correlated fashion. Glow ignition may be achieved by employing a multi-step avalanche chamber above a memory gap. Correlation is maintained during readout by successively pulsing each hit wire in one coordinate and sensing transmissions through glows in the other coordinate. Prototypes constructed by the authors are discussed along with the associated high voltage and readout systems

  13. A Panchromatic View of Brown Dwarf Aurorae

    Energy Technology Data Exchange (ETDEWEB)

    Pineda, J. Sebastian [University of Colorado Boulder, Laboratory for Atmospheric and Space Physics, 3665 Discovery Drive, Boulder CO, 80303 (United States); Hallinan, Gregg; Kao, Melodie M. [California Institute of Technology, Department of Astronomy, 1200 E. California Avenue, Pasadena CA, 91125 (United States)

    2017-09-01

    Stellar coronal activity has been shown to persist into the low-mass star regime, down to late M-dwarf spectral types. However, there is now an accumulation of evidence suggesting that at the end of the main sequence, there is a transition in the nature of the magnetic activity from chromospheric and coronal to planet-like and auroral, from local impulsive heating via flares and MHD wave dissipation to energy dissipation from strong large-scale magnetospheric current systems. We examine this transition and the prevalence of auroral activity in brown dwarfs through a compilation of multiwavelength surveys of magnetic activity, including radio, X-ray, and optical. We compile the results of those surveys and place their conclusions in the context of auroral emission as a consequence of large-scale magnetospheric current systems that accelerate energetic electron beams and drive the particles to impact the cool atmospheric gas. We explore the different manifestations of auroral phenomena, like H α , in brown dwarf atmospheres and define their distinguishing characteristics. We conclude that large-amplitude photometric variability in the near-infrared is most likely a consequence of clouds in brown dwarf atmospheres, but that auroral activity may be responsible for long-lived stable surface features. We report a connection between auroral H α emission and quiescent radio emission in electron cyclotron maser instability pulsing brown dwarfs, suggesting a potential underlying physical connection between quiescent and auroral emissions. We also discuss the electrodynamic engines powering brown dwarf aurorae and the possible role of satellites around these systems both to power the aurorae and seed the magnetosphere with plasma.

  14. A Panchromatic View of Brown Dwarf Aurorae

    Science.gov (United States)

    Pineda, J. Sebastian; Hallinan, Gregg; Kao, Melodie M.

    2017-09-01

    Stellar coronal activity has been shown to persist into the low-mass star regime, down to late M-dwarf spectral types. However, there is now an accumulation of evidence suggesting that at the end of the main sequence, there is a transition in the nature of the magnetic activity from chromospheric and coronal to planet-like and auroral, from local impulsive heating via flares and MHD wave dissipation to energy dissipation from strong large-scale magnetospheric current systems. We examine this transition and the prevalence of auroral activity in brown dwarfs through a compilation of multiwavelength surveys of magnetic activity, including radio, X-ray, and optical. We compile the results of those surveys and place their conclusions in the context of auroral emission as a consequence of large-scale magnetospheric current systems that accelerate energetic electron beams and drive the particles to impact the cool atmospheric gas. We explore the different manifestations of auroral phenomena, like Hα, in brown dwarf atmospheres and define their distinguishing characteristics. We conclude that large-amplitude photometric variability in the near-infrared is most likely a consequence of clouds in brown dwarf atmospheres, but that auroral activity may be responsible for long-lived stable surface features. We report a connection between auroral Hα emission and quiescent radio emission in electron cyclotron maser instability pulsing brown dwarfs, suggesting a potential underlying physical connection between quiescent and auroral emissions. We also discuss the electrodynamic engines powering brown dwarf aurorae and the possible role of satellites around these systems both to power the aurorae and seed the magnetosphere with plasma.

  15. Glow discharge techniques for conditioning high vacuum systems

    International Nuclear Information System (INIS)

    Dylla, H.F.

    1988-03-01

    A review is given of glow discharge techniques which are useful for conditioning vacuum vessels for high vacuum applications. Substantial development of glow discharge techniques has been done for the purpose of in-situ conditioning of the large ultrahigh vacuum systems for particle accelerators and magnetic fusion devices. In these applications the glow discharge treatments remove impurities from vessel surfaces in order to minimize particle-induced desorption coefficients. Cleaning mechanisms involve a mixture of sputtering and ion- (or neutral) induced desorption effects depending on the gas mixture (ArO 2 vs. H 2 ) and excitation method (DC, RF, and ECR). The author will review the methodology of glow discharge conditioning, diagnostic measurements provided by residual gas and surface composition analysis, and applications to vessel conditioning and materials processing. 76 refs., 16 figs

  16. Glow phenomenon surrounding the vertical stabilizer and OMS pods

    Science.gov (United States)

    1994-01-01

    This 35mm frame, photographed as the Space Shuttle Columbia was orbiting Earth during a 'night' pass, documents the glow phenomenon surrounding the vertical stabilizer and the Orbital Maneuvering System (OMS) pods of the spacecraft.

  17. Multifunctional Glow Discharge Analyzer for Spacecraft Monitoring, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Makel Engineering, Inc. (MEI) and Penn State University (PSU) propose to develop a highly sensitive spectrometer based on glow discharge emission for the...

  18. Research Ship Aurora Australis Underway Meteorological Data, Quality Controlled

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Research Ship Aurora Australis Underway Meteorological Data (delayed ~10 days for quality control) are from the Shipboard Automated Meteorological and Oceanographic...

  19. Aurora-A Oncogene in Human Ovarian Cancer

    National Research Council Canada - National Science Library

    Cheng, Jin Q

    2006-01-01

    .... Ectopic expression of Aurora-A renders cells resistant to cisplatin (CDDP), etoposide and paclitaxel-induced apoptosis and stimulates Akt1 and Akt2 activity in wild-type p53 but not p53-null ovarian cancer cells...

  20. Flickering aurora observations at 500 frames per second

    Science.gov (United States)

    McHarg, M. G.; Hampton, D. L.; Stenbaek-Nielsen, H.; Michell, R.

    2017-12-01

    Flickering aurora is thought to be produced when incoming energetic electrons are bunched by Oxygen ion cyclotron waves. The light resulting from the bunched electrons then carry information about the wave particle interactions which cause the bunching. Flickering aurora observed by standard frame rate camera shown a pronounced narrow frequency "flicker" at 3-10 Hz. This frequency matches the ion cyclotron frequency of oxygen ions at altitudes between 2000-5000km. We report on observations of flickering aurora which were obtained at 500 frames per second using an intensified Phantom high speed camera with a 20 degree field of view at magnetic zenith on 2 March 2017. In addition to the narrow frequency results previously reported with standard frame rate imagers, we observe broad band frequencies up to approximately 30 Hz. We report on the spatial distribution of both the narrow and broad band frequency modulations, and compare these to various theoretical models of flickering aurora.

  1. Some Behavioural Responses Of Limicolaria aurora Exposed To ...

    African Journals Online (AJOL)

    application of 0.1 M concentration of gramoxone (contact herbicide, paraquat chloride) on Limicolaria aurora were determined and compared with control using Amaranthus sp. as bait. Responses were measured through normal feeding and crawling, ...

  2. Studies of the cathode region of the dc glow discharge

    International Nuclear Information System (INIS)

    Den Hartog, E.A.

    1989-01-01

    Laser-based spectroscopic diagnostics are employed to gain an increased understanding of the cathode region of a dc helium glow discharge. A pair of diagnostics are used to determine the density (n e ) and temperature (T e ) of low energy electrons confined in the negative glow. The first diagnostic is based on the observed suppression of 2 1 S metastables in the negative glow due to electron collisions. The reaction primarily responsible for the suppression is the metastable spin conversion reaction which converts 2 1 S metastables to 2 3 S metastables. 2 1 S and 2 3 S metastable densities and 2 1 P resonant atom densities are mapped as a function of position, and the maps are analyzed to determine a relation between n e and T e . A second relation between n e and T e is determined by measuring the electron impact transfer rate between Rydberg levels. The intersection of the two relations yields n e and T e for the low energy electrons in the negative glow. Empirical determinations of the current balance at the cathode surface and metastable production are compared to results of Monte Carlo simulations. The current balance comparison leads to the prediction of a field reversal at the cathode fall-negative glow boundary. As a consequence of this field reversal a simple model of the negative glow is suggested, in which the plasma in the negative glow diffuses toward the anode in an ambipolar-like process. Ion production in the negative glow is determined from Monte Carlo simulations. An equation is written balancing production and diffusion losses. This equation is written balancing production and diffusion losses. This equation leads to a third relation between n e and T e which is compared to the earlier results

  3. Surface modification of polyimide (PI) film using water cathode atmospheric pressure glow discharge plasma

    International Nuclear Information System (INIS)

    Zheng Peichao; Liu Keming; Wang Jinmei; Dai Yu; Yu Bin; Zhou Xianju; Hao Honggang; Luo Yuan

    2012-01-01

    Highlights: ► Equipment called water cathode atmospheric pressure glow discharge was used to improve the hydrophilicity of polyimide films. ► The data shows good homogeneity and the variation trends of contact angles are different for polar and non-polar testing liquids. ► The thickness of liquid layer plays an important role in plasma processing and directly affects the treatment effect. ► Surface hydrophilicity after plasma treatment is improved partly due to the increase in the roughness. ► The hydrophilicity of polyimide films is still better than untreated ones after long-term storage. - Abstract: The industrial use of polyimide film is limited because of undesirable properties such as poor wettability. In the present paper, a new kind of equipment called water cathode atmospheric pressure glow discharge was used to improve the surface properties of polyimide films and made them useful to technical applications. The changes in hydrophilicity of modified polyimide film surfaces were investigated by contact angle, surface energy and water content measurements as a function of treatment time. The results obtained show good treatment homogeneity and that the variation trends of contact angles are different for polar and non-polar testing liquids, while surface energy and water content are significantly enhanced with the increase of treatment time until they achieve saturated values after 60 s plasma treatment. Also, the thickness of liquid layer plays an important role in plasma processing and directly affects the treatment effect. Changes in morphology of polyimide films were analyzed by atomic force microscope and the results indicate that surface hydrophilicity after plasma treatment are improved partly due to the increase in the roughness. In addition, polyimide films treated by plasma are subjected to an ageing process to determine the durability of plasma treatment. It is found that the hydrophilicity is still better than untreated ones though the

  4. tgcd: An R package for analyzing thermoluminescence glow curves

    Directory of Open Access Journals (Sweden)

    Jun Peng

    2016-01-01

    Full Text Available Thermoluminescence (TL glow curves are widely used in dosimetric studies. Many commercial and free-distributed programs are used to deconvolute TL glow curves. This study introduces an open-source R package tgcd to conduct TL glow curve analysis, such as kinetic parameter estimation, glow peak simulation, and peak shape analysis. TL glow curves can be deconvoluted according to the general-order empirical expression or the semi-analytical expression derived from the one trap-one recombination center (OTOR model based on the Lambert W function by using a modified Levenberg–Marquardt algorithm from which any of the parameters can be constrained or fixed. The package provides an interactive environment to initialize parameters and offers an automated “trial-and-error” protocol to obtain optimal fit results. First-order, second-order, and general-order glow peaks (curves are simulated according to a number of simple kinetic models. The package was developed using a combination of Fortran and R programming languages to improve efficiency and flexibility.

  5. Quantifying Temporal and Spatial Characteristics of Pulsating Aurora

    Science.gov (United States)

    Marchese, A. K.; Samara, M.; Michell, R.

    2017-12-01

    Aurorae are phenomena of colorful light due to charged solar wind particles colliding with gases in Earth's atmosphere. These events tend to be more prominent in higher latitudes since the particles travel along the magnetic field lines until they reach the poles where they enter the atmosphere. The effects of these energetic particles, however, also may damage technology. It is important to study aurorae to understand solar activity and how the magnetosphere responds to it to better deal with these problems. Imagers are located in Montana and Alaska facing towards the sky in order to take pictures of the aurora. Using the data from the imagers, numerous mathematical techniques were applied in order to extract quantitative information from the pictures to analyze pulsating aurora and study the differences between the aurora in Alaska and Montana. The two locations are at different latitudes and, thus, it is expected that they have different characteristics. Alaska, which is at a higher latitude, should have a more intense aurora than Montana.

  6. Radio Aurora Explorer: Mission science and radar system

    Science.gov (United States)

    Bahcivan, H.; Cutler, J. W.

    2012-04-01

    The Radio Aurora Explorer (RAX) satellite is the first of several satellites funded under the NSF CubeSat-based Space Weather and Atmospheric Research Program. RAX is a ground-to-space bi-static radar remote sensing experiment designed to measure and understand the causes of meter-scale ionospheric irregularities. Also known as field-aligned irregularities (FAI), such non-thermal, coherent fluctuations of electron density occur in response to strong ionospheric flows or plasma density gradients during geomagnetic disturbances and are considered a space weather concern due to disruption to communication and navigation signals. The RAX CubeSat was launched in November 2010 and conducted a single experiment in coordination with the Poker Flat Incoherent Scatter Radar. Due to geophysical inactivity, e.g., lack of strong ionospheric electric fields and low ionospheric densities, no FAI were expected or observed. However, the radar receiver payload operation was successfully demonstrated, including the capability to sense signals as low as -110 dBm, the capability of transmitter-receiver synchronization and accurate ranging, processing of 1.2 GB of raw radar data on board in less than 1 hour, and the downlink of the science results within three-four passes. Analysis of the payload data shows that the noise level is sufficiently low. Although the interference level is a concern, it does not appear to significantly limit the measurements. Toward the end of December 2010, the solar power system gradually degraded and the mission terminated in early February 2011 after prolonged loss of contact with the satellite. Meanwhile, RAX II was launched in October 2011 to a polar orbit. This paper describes the RAX science and radar system and presents the results from the first experiment conducted.

  7. Oxygen negative glow: reactive species and emissivity

    International Nuclear Information System (INIS)

    Sahli, Khaled

    1991-01-01

    This research thesis addresses the study of a specific type of oxygen plasma created by electron beams (1 keV, 20 mA/cm 2 ), negative glow of a luminescent discharge in abnormal regime. The objective is to test the qualities of this plasma as source of two 'active' species of oxygen (singlet molecular oxygen and atomic oxygen) which are useful in applications. The experiment mainly bears on the use of VUV (120 to 150 nm) absorption spectroscopy measurements of concentrations of these both species, and on the recording of plasma emissivity space profiles in the visible region (450 to 850 nm). It appears that low concentrations of singlet oxygen definitely exclude this type of discharge for iodine laser applications. On the contrary, concentrations measured for atomic oxygen show it is a good candidate for the oxidation of large surfaces by sheets of beams. The satisfying comparison of emissivity results with a published model confirm the prevailing role of fast electrons, and gives evidence of an important effect of temperature: temperature can reach 1000 K, and this is in agreement with the presented measurement [fr

  8. The impact of an ICME on the Jovian X-ray aurora.

    Science.gov (United States)

    Dunn, William R; Branduardi-Raymont, Graziella; Elsner, Ronald F; Vogt, Marissa F; Lamy, Laurent; Ford, Peter G; Coates, Andrew J; Gladstone, G Randall; Jackman, Caitriona M; Nichols, Jonathan D; Rae, I Jonathan; Varsani, Ali; Kimura, Tomoki; Hansen, Kenneth C; Jasinski, Jamie M

    2016-03-01

    We report the first Jupiter X-ray observations planned to coincide with an interplanetary coronal mass ejection (ICME). At the predicted ICME arrival time, we observed a factor of ∼8 enhancement in Jupiter's X-ray aurora. Within 1.5 h of this enhancement, intense bursts of non-Io decametric radio emission occurred. Spatial, spectral, and temporal characteristics also varied between ICME arrival and another X-ray observation two days later. Gladstone et al. (2002) discovered the polar X-ray hot spot and found it pulsed with 45 min quasiperiodicity. During the ICME arrival, the hot spot expanded and exhibited two periods: 26 min periodicity from sulfur ions and 12 min periodicity from a mixture of carbon/sulfur and oxygen ions. After the ICME, the dominant period became 42 min. By comparing Vogt et al. (2011) Jovian mapping models with spectral analysis, we found that during ICME arrival at least two distinct ion populations, from Jupiter's dayside, produced the X-ray aurora. Auroras mapping to magnetospheric field lines between 50 and 70  R J were dominated by emission from precipitating sulfur ions (S 7+,…,14+ ). Emissions mapping to closed field lines between 70 and 120  R J and to open field lines were generated by a mixture of precipitating oxygen (O 7+,8+ ) and sulfur/carbon ions, possibly implying some solar wind precipitation. We suggest that the best explanation for the X-ray hot spot is pulsed dayside reconnection perturbing magnetospheric downward currents, as proposed by Bunce et al. (2004). The auroral enhancement has different spectral, spatial, and temporal characteristics to the hot spot. By analyzing these characteristics and coincident radio emissions, we propose that the enhancement is driven directly by the ICME through Jovian magnetosphere compression and/or a large-scale dayside reconnection event.

  9. The aurora at quite magnetospheric conditions: Repeatability and dipole tilt angle dependence

    International Nuclear Information System (INIS)

    Oznovich, I.; Eastes, R.W.; Huffman, R.E.; Tur, M.; Glaser, I.

    1993-01-01

    Is there a magnetospheric ground state? Do the position and size of the auroral oval depend on the magnetic dipole tilt angle at quiet magnetospheric conditions? In order to address these questions, northern hemisphere images of the aurora at 1356 Angstrom, obtained by Polar BEAR at solar minimum (beginning of 1987), were related to high temporal resolution IPM 8 measurements of the interplanetary magnetic field, to solar wind velocity, and to the ground-based activity index Kp. The first problem was addressed by a two-dimensional correlation study of the repeatability of auroral emissions in corrected geomagnetic space at conditions of minimum energy transfer from the magnetosphere. The correlation measure of auroral images was 0.6-0.85. Error simulations indicate that given the uncertainties in pixel position and intensity, the maximum expected value of the correlation measure is 0.65-0.9. The notion of a ground state magnetosphere is therefore supported by this data. Repeatability was found at the same level regardless of time or reconfigurations of the magnetosphere between images and independent of magnetic time sector. The second problem was addressed by relating latitudinal shifts of the aurora with dipole tilt angle without resorting to auroral boundary specification. This data indicate that the latitude of the continuous aurora is related to the dipole tilt angle at quiet magnetospheric conditions. In the winter hemisphere a 10 degrees increase in the dipole tilt angle causes a 1 degree decrease (increase) in the latitude of auroral emissions at noon (midnight). The magnetic local time distribution of the latitudinal shifts with dipole tilt angle support a simple model in which the dipole tilt angle determines the position of the center of the auroral circle along the magnetic meridian 1320-0120 MLT (for IMF B y positive) and does not affect its radius. 22 refs., 8 figs

  10. Sporadic aurorae observed in East Asia

    Directory of Open Access Journals (Sweden)

    D. M. Willis

    2007-03-01

    Full Text Available All the accessible auroral observations recorded in Chinese and Japanese histories during the interval AD 1840–1911 are investigated in detail. Most of these auroral records have never been translated into a Western language before. The East Asian auroral reports provide information on the date and approximate location of each auroral observation, together with limited scientific information on the characteristics of the auroral luminosity such as colour, duration, extent, position in the sky and approximate time of occurrence. The full translations of the original Chinese and Japanese auroral records are presented in an appendix, which contains bibliographic details of the various historical sources. (There are no known reliable Korean observations during this interval. A second appendix discusses a few implausible "auroral" records, which have been rejected. The salient scientific properties of all exactly dated and reliable East Asian auroral observations in the interval AD 1840–1911 are summarised succinctly. By comparing the relevant scientific information on exactly dated auroral observations with the lists of great geomagnetic storms compiled by the Royal Greenwich Observatory, and also the tabulated values of the Ak (Helsinki and aa (Greenwich and Melbourne magnetic indices, it is found that 5 of the great geomagnetic storms (aa>150 or Ak>50 during either the second half of the nineteenth century or the first decade of the twentieth century are clearly identified by extensive auroral displays observed in China or Japan. Indeed, two of these great storms produced auroral displays observed in both countries on the same night. Conversely, at least 29 (69% of the 42 Chinese and Japanese auroral observations occurred at times of weak-to-moderate geomagnetic activity (aa or Ak≤50. It is shown that these latter auroral displays are very similar to the more numerous (about 50 examples of sporadic aurorae observed in the United States

  11. Sporadic aurorae observed in East Asia

    Directory of Open Access Journals (Sweden)

    D. M. Willis

    2007-03-01

    aurorae observed in the United States during the interval AD 1880–1940. The localised nature and spatial structure of some sporadic aurorae observed in East Asia is indicated by the use of descriptive terms such as "lightning", "rainbow", "streak" and "grid".

  12. Dancing Lights: Creating the Aurora Story

    Science.gov (United States)

    Wood, E. L.; Cobabe-Ammann, E. A.

    2009-12-01

    Science tells a story about our world, our existence, our history, and the larger environment our planet occupies. Bearing this in mind, we created a series of lessons for 3rd-5th grades using a cross-disciplinary approach to teaching about the aurora by incorporating stories, photos, movies, and geography into the science in order to paint a broad picture and answer the question, “why do we care?” The fundamental backbone of the program is literacy. Students write and illustrate fiction and non-fiction work, poetry, and brochures that solidify both language arts skills and science content. In a time when elementary teachers relegate science to less than one hour per week, we have developed a novel science program that can be easily integrated with other topics during the typical school day to increase the amount of science taught in a school year. We are inspiring students to take an interest in the natural world with this program, a stepping-stone for larger things.

  13. Precipitation of relativistic electrons of the Van Allen belts into the proton aurora

    Energy Technology Data Exchange (ETDEWEB)

    Jordanova, Vania K [Los Alamos National Laboratory; Miyoshi, Y [NAGOYA UNIV; Sakaguchi, K [NAGOYA UNIV; Shiokawa, K [NAGOYA UNIV; Evans, D S [SEC/NOAA; Albert, Jay [AFRL; Connors, M [UNIV OF ATHABASCA

    2008-01-01

    The Van Allen electron belts consist of two regions encircling the earth in which relativistic electrons are trapped in the earth's magnetic field. Populations of relativistic electrons in the Van Allen belts vary greatly with geomagnetic disturbance and they are a major source of damage to space vehicles. In order to know when and by how much these populations of relativistic electrons increase, it is important to elucidate not only the cause of acceleration of relativistic electrons but also the cause of their loss from the Van Allen belts. Here we show the first evidence that left-hand polarized electromagnetic ion cyclotron (EMIC) plasma waves can cause the loss of relativistic electrons into the atmosphere, on the basis of results of an excellent set of ground and satellite observations showing coincident precipitation of ions with energies of tens of keV and of relativistic electrons into an isolated proton aurora. The proton aurora was produced by precipitation of ions with energies of tens of keV due to EMIC waves near the plasma pause, which is a manifestation of wave-particle interactions. These observations clarify that ions with energies of tens of keV affect the evolution of relativistic electrons in the Van Allen belts via parasitic resonance with EMIC waves, an effect that was first theoretically predicted in the early 1970's.

  14. Nitrogen and oxygen incorporation into glow discharge polymers

    International Nuclear Information System (INIS)

    Engelman, R.A.; Yasuda, H.K.

    1990-01-01

    Several facets of nitrogen incorporation into glow discharge polymers were investigated. First, the deposition behavior for the glow discharge polymerization of a methane/ammonia mixture was studied. The plot of D/FM versus W/FM was found to result in a separate curve for each ammonia flow rate, independent of the methane flow rate. A linear relationship was observed between D/(FM) CH4 and W/FM, indicating that the rate of decomposition of methane is the limiting factor in polymer deposition. The rate of ammonia incorporation into the glow discharge polymer was found to be independent of the power input. Secondly, the ablation of nitrogen from previous glow discharge polymer deposits, and the subsequent incorporation into methane plasma polymers, was investigated. No incorporation of nitrogen occurred due to the exposure of trapped reactive sites to air. In contrast, oxygen was difficult to incorporate into the polymer film during the deposition process, but glow discharge deposits readily oxidized upon exposure to air

  15. Prediction of blue, red and green aurorae at Mars

    Science.gov (United States)

    Lilensten, J.; Bernard, D.; Barthélémy, M.; Gronoff, G.; Simon Wedlund, C.; Opitz, A.

    2015-09-01

    The upper atmosphere of Mars is a laboratory for better understanding the planetary atmosphere evolution, and is an example of the interaction of the solar wind with an unmagnetized planet that has only patches of crustal magnetic field. In that context, several space missions were launched to study the Martian environment and its aurorae, notably ESA's Mars Express discovered the first aurora-like structures, and more recently NASA's MAVEN, which is dedicated to understand the atmospheric escape. However, none of the existing missions have spectrometers in the visible spectral range for the observation of the upper atmosphere and the aurorae, but there are UV spectrometer which can be used to infer visible aurora emission. The UV aurorae on Mars have a counterpart in the visible spectral range which should be detectable under the right conditions. We discuss what are the most favorable conditions to observe these aurorae discernible with the naked eye. In this paper, we simulate the Martian aurora in the visible spectral range both with an experimental setup (the Planeterrella, which we use to measure intensity with respect to the naked eye) and with a numerical ionosphere simulation model (Trans*/Aeroplanets). We show that the electron impact on CO2 produces strong emissions at 412 nm and 434 nm, i.e., in the blue part of the visible spectrum which are due to the CO2+(A) Fox-Duffendack-Barker bands. The modeling of the electron transport at Mars shows that these blue emissions as well as the emissions of the 630 nm (red) and 557.7 nm (green) lines of atomic oxygen may be observable several times during a solar cycle during strong solar events. The absence of visible spectrometers dedicated to these observations onboard existing space missions and the location of the different Martian rovers, far from the vertically aligned crustal magnetic field lines of Mars, have prevented so far the observations of such an aurora. In the foreseeable future, two missions may

  16. Aurora Borealis, A Painting by Frederic Edwin Church

    Science.gov (United States)

    Love, J. J.

    2015-12-01

    This year marks the sesquicentennial anniversary of the end of the American Civil War. In 1865, the same year as the War's end, the great American landscape artist, Frederic Edwin Church, unveiled Aurora Borealis, a painting that depicts a fantastic, far-northern place, an auroral arch stretched across a quiet night-time sky, above dark mountains and a frozen sea. Church was born in Connecticut, lived in New York, and traveled to Labrador; he would have often seen the northern lights. Church might have also been influenced by the spectacular displays of aurora that were caused by some unusually intense magnetic storms in 1859. Aurora Borealis can certainly be interpreted in terms of 19th-century romanticism, scientific philosophy, and Arctic missions of exploration, all subjects of interest to Church. As with so many of his paintings, Church's meticulous attention to detail in Aurora Borealis reveals his deep admiration of nature. But his depiction of auroral light is a curious and possibly intentional departure from natural verisimilitude. Some art historians have suggested that Church painted Aurora Borealis as a subdued tribute to the end of the Civil War, with the drapery of auroral light forming an abstract representation of the American flag. If so, then colors of the flag have been unfurled across a cold and barren landscape, not in extravagant celebration, but in somber recognition of the reality of post-war desolation and an uncertain future.

  17. Fast DPCM scheme for lossless compression of aurora spectral images

    Science.gov (United States)

    Kong, Wanqiu; Wu, Jiaji

    2016-10-01

    Aurora has abundant information to be stored. Aurora spectral image electronically preserves spectral information and visual observation of aurora during a period to be studied later. These images are helpful for the research of earth-solar activities and to understand the aurora phenomenon itself. However, the images are produced with a quite high sampling frequency, which leads to the challenging transmission load. In order to solve the problem, lossless compression turns out to be required. Indeed, each frame of aurora spectral images differs from the classical natural image and also from the frame of hyperspectral image. Existing lossless compression algorithms are not quite applicable. On the other hand, the key of compression is to decorrelate between pixels. We consider exploiting a DPCM-based scheme for the lossless compression because DPCM is effective for decorrelation. Such scheme makes use of two-dimensional redundancy both in the spatial and spectral domain with a relatively low complexity. Besides, we also parallel it for a faster computation speed. All codes are implemented on a structure consists of nested for loops of which the outer and the inner loops are respectively designed for spectral and spatial decorrelation. And the parallel version is represented on CPU platform using different numbers of cores. Experimental results show that compared to traditional lossless compression methods, the DPCM scheme has great advantage in compression gain and meets the requirement of real-time transmission. Besides, the parallel version has expected computation performance with a high CPU utilization.

  18. Making Sense of the Aurora: A Research Project

    Directory of Open Access Journals (Sweden)

    Robert Marc Friedman

    2012-05-01

    Full Text Available The article provides an introduction to a on-going research project based at University of Tromsø that seeks to analyze the history of efforts to make sense of the aurora borealis from the early 1700s through to the Cold War. Following brilliant displays of the northern lights in the early eighteenth century, natural philosophers strove to explain this phenomenon that evoked widespread fear and superstition. It was not until well into the twentieth century that consensual explanation emerged for this, one of the great enigmas in the history of science. From the start, the quest to explain the aurora borealis became enmeshed with patriotic science and nationalist sentiments. The history of efforts to understand the nature and cause of the aurora poses a number of thematic problems. Being a fleeting and at times rapidly changing phenomenon, only occasionally seen south of far-northern latitudes, the aurora needed to be constituted as an object able to be brought into the domain of rational science. Observational accounts of the aurora came most often from by personsliving or travelling in the far north or in the Arctic, but these persons were generally not trained scientists: Whose witnessing counted and how was authority negotiated among professional scientists and amateurs?

  19. Aurora B interaction of centrosomal Nlp regulates cytokinesis.

    Science.gov (United States)

    Yan, Jie; Jin, Shunqian; Li, Jia; Zhan, Qimin

    2010-12-17

    Cytokinesis is a fundamental cellular process, which ensures equal abscission and fosters diploid progenies. Aberrant cytokinesis may result in genomic instability and cell transformation. However, the underlying regulatory machinery of cytokinesis is largely undefined. Here, we demonstrate that Nlp (Ninein-like protein), a recently identified BRCA1-associated centrosomal protein that is required for centrosomes maturation at interphase and spindle formation in mitosis, also contributes to the accomplishment of cytokinesis. Through immunofluorescent analysis, Nlp is found to localize at midbody during cytokinesis. Depletion of endogenous Nlp triggers aborted division and subsequently leads to multinucleated phenotypes. Nlp can be recruited by Aurora B to the midbody apparatus via their physical association at the late stage of mitosis. Disruption of their interaction induces aborted cytokinesis. Importantly, Nlp is characterized as a novel substrate of Aurora B and can be phosphorylated by Aurora B. The specific phosphorylation sites are mapped at Ser-185, Ser-448, and Ser-585. The phosphorylation at Ser-448 and Ser-585 is likely required for Nlp association with Aurora B and localization at midbody. Meanwhile, the phosphorylation at Ser-185 is vital to Nlp protein stability. Disruptions of these phosphorylation sites abolish cytokinesis and lead to chromosomal instability. Collectively, these observations demonstrate that regulation of Nlp by Aurora B is critical for the completion of cytokinesis, providing novel insights into understanding the machinery of cell cycle progression.

  20. Aurora B Interaction of Centrosomal Nlp Regulates Cytokinesis*

    Science.gov (United States)

    Yan, Jie; Jin, Shunqian; Li, Jia; Zhan, Qimin

    2010-01-01

    Cytokinesis is a fundamental cellular process, which ensures equal abscission and fosters diploid progenies. Aberrant cytokinesis may result in genomic instability and cell transformation. However, the underlying regulatory machinery of cytokinesis is largely undefined. Here, we demonstrate that Nlp (Ninein-like protein), a recently identified BRCA1-associated centrosomal protein that is required for centrosomes maturation at interphase and spindle formation in mitosis, also contributes to the accomplishment of cytokinesis. Through immunofluorescent analysis, Nlp is found to localize at midbody during cytokinesis. Depletion of endogenous Nlp triggers aborted division and subsequently leads to multinucleated phenotypes. Nlp can be recruited by Aurora B to the midbody apparatus via their physical association at the late stage of mitosis. Disruption of their interaction induces aborted cytokinesis. Importantly, Nlp is characterized as a novel substrate of Aurora B and can be phosphorylated by Aurora B. The specific phosphorylation sites are mapped at Ser-185, Ser-448, and Ser-585. The phosphorylation at Ser-448 and Ser-585 is likely required for Nlp association with Aurora B and localization at midbody. Meanwhile, the phosphorylation at Ser-185 is vital to Nlp protein stability. Disruptions of these phosphorylation sites abolish cytokinesis and lead to chromosomal instability. Collectively, these observations demonstrate that regulation of Nlp by Aurora B is critical for the completion of cytokinesis, providing novel insights into understanding the machinery of cell cycle progression. PMID:20864540

  1. Optical tomography of the aurora and EISCAT

    Directory of Open Access Journals (Sweden)

    H. U. Frey

    Full Text Available Tomographic reconstruction of the three-dimensional auroral arc emission is used to obtain vertical and horizontal distributions of the optical auroral emission. Under the given experimental conditions with a very limited angular range and a small number of observers, algebraic reconstruction methods generally yield better results than transform techniques. Different algebraic reconstruction methods are tested with an auroral arc model and the best results are obtained with an iterative least-square method adapted from emission-computed tomography. The observation geometry used during a campaign in Norway in 1995 is tested with the arc model and root-mean-square errors, to be expected under the given geometrical conditions, are calculated. Although optimum geometry was not used, root-mean-square errors of less than 2% for the images and of the order of 30% for the distribution could be obtained. The method is applied to images from real observations. The correspondence of original pictures and projections of the reconstructed volume is discussed, and emission profiles along magnetic field lines through the three-dimensionally reconstructed arc are calibrated into electron density profiles with additional EISCAT measurements. Including a background profile and the temporal changes of the electron density due to recombination, good agreement can be obtained between measured profiles and the time-sequence of calculated profiles. These profiles are used to estimate the conductivity distribution in the vicinity of the EISCAT site. While the radar can only probe the ionosphere along the radar beam, the three-dimensional tomography enables conductivity estimates in a large area around the radar site.

    Key words. Tomography · Aurora · EISCAT · Ionosphere · Conductivity

  2. Optical tomography of the aurora and EISCAT

    Directory of Open Access Journals (Sweden)

    H. U. Frey

    1998-10-01

    Full Text Available Tomographic reconstruction of the three-dimensional auroral arc emission is used to obtain vertical and horizontal distributions of the optical auroral emission. Under the given experimental conditions with a very limited angular range and a small number of observers, algebraic reconstruction methods generally yield better results than transform techniques. Different algebraic reconstruction methods are tested with an auroral arc model and the best results are obtained with an iterative least-square method adapted from emission-computed tomography. The observation geometry used during a campaign in Norway in 1995 is tested with the arc model and root-mean-square errors, to be expected under the given geometrical conditions, are calculated. Although optimum geometry was not used, root-mean-square errors of less than 2% for the images and of the order of 30% for the distribution could be obtained. The method is applied to images from real observations. The correspondence of original pictures and projections of the reconstructed volume is discussed, and emission profiles along magnetic field lines through the three-dimensionally reconstructed arc are calibrated into electron density profiles with additional EISCAT measurements. Including a background profile and the temporal changes of the electron density due to recombination, good agreement can be obtained between measured profiles and the time-sequence of calculated profiles. These profiles are used to estimate the conductivity distribution in the vicinity of the EISCAT site. While the radar can only probe the ionosphere along the radar beam, the three-dimensional tomography enables conductivity estimates in a large area around the radar site.Key words. Tomography · Aurora · EISCAT · Ionosphere · Conductivity

  3. Use of universal functional optimisation for TL glow curve analysis

    International Nuclear Information System (INIS)

    Pernicka, F.; Linh, H.Q.

    1996-01-01

    The effective use of any TL instrument requires an efficient software package to be able to fulfil different tasks required by research and practical applications. One of the standard features of the package used at the NPI Prague is the application of the interactive modular system Universal Functional Optimisation (UFO) for glow curve deconvolution. The whole system has been tested on standard glow curves using different models of the TL process (a single peak described by the Podgorsak approximation, first order kinetics and/or general order kinetics). Calculated values of basic TL parameters (E and s) show a good agreement with the results obtained by other authors. The main advantage of the system is in its modularity that enables flexible changes in the TL model and mathematical procedures of the glow curve analysis. (author)

  4. Extension of spatiotemporal chaos in glow discharge-semiconductor systems

    Energy Technology Data Exchange (ETDEWEB)

    Akhmet, Marat, E-mail: marat@metu.edu.tr; Fen, Mehmet Onur [Department of Mathematics, Middle East Technical University, 06800 Ankara (Turkey); Rafatov, Ismail [Department of Physics, Middle East Technical University, 06800 Ankara (Turkey)

    2014-12-15

    Generation of chaos in response systems is discovered numerically through specially designed unidirectional coupling of two glow discharge-semiconductor systems. By utilizing the auxiliary system approach, [H. D. I. Abarbanel, N. F. Rulkov, and M. M. Sushchik, Phys. Rev. E 53, 4528–4535 (1996)] it is verified that the phenomenon is not a chaos synchronization. Simulations demonstrate various aspects of the chaos appearance in both drive and response systems. Chaotic control is through the external circuit equation and governs the electrical potential on the boundary. The expandability of the theory to collectives of glow discharge systems is discussed, and this increases the potential of applications of the results. Moreover, the research completes the previous discussion of the chaos appearance in a glow discharge-semiconductor system [D. D. Šijačić U. Ebert, and I. Rafatov, Phys. Rev. E 70, 056220 (2004).].

  5. Spectroscopic characterisation of an atmospheric pressure glow discharge

    International Nuclear Information System (INIS)

    Gomez, S.; Steen, P.G.; Morrow, T.; Graham, W.G.

    2001-01-01

    Recently there has been considerable interest in atmospheric discharges operating in a glow discharge mode i.e. with a spatial and sheath structure similar to that of low pressure glow discharges. Here spectroscopy has been used to characterise an atmospheric pressure glow discharge (APGD), operating with either dry air, argon or helium gas flowing through the inter-electrode space and with the inter-electrode gap either free or with woven polypropylene or polyester samples present. Emission spectroscopy is used to determine the rotational and vibrational temperature of the nitrogen gas, while electron temperatures are determined from the relative intensities of Ar emission lines. Ozone production is monitored by a simple absorption technique to evaluate its potential in process control

  6. Simulation of nonstationary phenomena in atmospheric-pressure glow discharge

    International Nuclear Information System (INIS)

    Korolev, Yu. D.; Frants, O. B.; Nekhoroshev, V. O.; Suslov, A. I.; Kas’yanov, V. S.; Shemyakin, I. A.; Bolotov, A. V.

    2016-01-01

    Nonstationary processes in atmospheric-pressure glow discharge manifest themselves in spontaneous transitions from the normal glow discharge into a spark. In the experiments, both so-called completed transitions in which a highly conductive constricted channel arises and incomplete transitions accompanied by the formation of a diffuse channel are observed. A model of the positive column of a discharge in air is elaborated that allows one to interpret specific features of the discharge both in the stationary stage and during its transition into a spark and makes it possible to calculate the characteristic oscillatory current waveforms for completed transitions into a spark and aperiodic ones for incomplete transitions. The calculated parameters of the positive column in the glow discharge mode agree well with experiment. Data on the densities of the most abundant species generated in the discharge (such as atomic oxygen, metastable nitrogen molecules, ozone, nitrogen oxides, and negative oxygen ions) are presented.

  7. Simulation of nonstationary phenomena in atmospheric-pressure glow discharge

    Science.gov (United States)

    Korolev, Yu. D.; Frants, O. B.; Nekhoroshev, V. O.; Suslov, A. I.; Kas'yanov, V. S.; Shemyakin, I. A.; Bolotov, A. V.

    2016-06-01

    Nonstationary processes in atmospheric-pressure glow discharge manifest themselves in spontaneous transitions from the normal glow discharge into a spark. In the experiments, both so-called completed transitions in which a highly conductive constricted channel arises and incomplete transitions accompanied by the formation of a diffuse channel are observed. A model of the positive column of a discharge in air is elaborated that allows one to interpret specific features of the discharge both in the stationary stage and during its transition into a spark and makes it possible to calculate the characteristic oscillatory current waveforms for completed transitions into a spark and aperiodic ones for incomplete transitions. The calculated parameters of the positive column in the glow discharge mode agree well with experiment. Data on the densities of the most abundant species generated in the discharge (such as atomic oxygen, metastable nitrogen molecules, ozone, nitrogen oxides, and negative oxygen ions) are presented.

  8. Target surface condition during reactive glow discharge sputtering of copper

    International Nuclear Information System (INIS)

    Depla, D; Haemers, J; Gryse, R De

    2002-01-01

    During reactive glow discharge sputtering of copper in an argon/nitrogen plasma, we noticed an abrupt change of the target voltage and the deposition rate when the nitrogen concentration in the plasma exceeds a critical value. To explain this behaviour, the target surface after reactive glow discharge sputtering was examined by x-ray photoelectron spectroscopy (XPS). An experimental arrangement was constructed that allows direct transfer of the glow discharge cathode to the XPS analysis chamber without air exposure. These XPS measurements revealed that several different chemical states of nitrogen are present in the layer that forms on the target surface. The relative concentration of these different states changes when the critical nitrogen concentration in the plasma is exceeded

  9. [The glow discharge as an atomization and ionization source

    International Nuclear Information System (INIS)

    1990-01-01

    This is to summarize the research progress in this project at the University of Florida over the past 13 months. In keeping with the directions of the Federal Demonstration Project, the report will be brief, presenting an overview of the major findings. We have continued the study of the glow discharge, primarily as an ionization source for elemental analysis. Glow discharge interest continues to grow in the analytical chemistry community as evidenced by the number of special symposia at major conferences, by the new researchers entering the field, and by the introduction of new instrumentation. There is little doubt that glow discharge mass spectrometry, for example, is now a major technique in the elemental analysis of solids

  10. Laser ablation/ionization studies in a glow discharge

    International Nuclear Information System (INIS)

    Hess, K.R.; Harrison, W.W.

    1985-01-01

    The pin cathode glow discharge is used in the laboratory as an atomization/ionization source for a variety of applications, including solids mass spectrometry. Coupled with a tunable dye laser, the glow discharge may also serve as an atom reservoir for resonance ionization mass spectrometry in which the laser ionizes the discharge sputtered atoms. By tightly focusing the laser onto solid samples, various ablation effects may also be investigated. The laser may be used to generate an ionized plasma which may be directly analyzed by mass spectrometry. Alternatively, the ablated neutral atoms may be used in post-ablation excitation/ionization processes, in this case the glow discharge. The results of these investigations are the basis of this paper

  11. Aurora Borealis Experiment (ABX): A Planeterrella for Education and Outreach

    Science.gov (United States)

    McNulty, Michael; Carpe, Andy; Zwicker, Andrew

    2013-10-01

    The Planeterrella is an experiment invented by Jean Lilensten of the Laboratoire de Planetologie de Grenoble in France designed to simulate aurorae of various planets. It is done by placing two differently sized aluminum spheres in a bell jar with a pressure of approximately 75 mTorr. Each sphere has magnets inside and is electrically biased. An electrode with the opposite electrical bias is inserted into the bell jar so that the voltage between them is on the order of 300 V. A plasma is then created and an aurora is formed around the magnetic poles of the spheres or near the edge of the electrode. We have made a modified version of the planeterrella, called the Aurora Borealis Experiment (ABX), based upon Lilensten's plans. We will present the technical details of the experiment and preliminary results of its use with a variety of different audiences.

  12. Spectroscopy and probe diagnostics of dc spherical glow discharge

    International Nuclear Information System (INIS)

    Zhovtyansky, V.A.; Nazarenko, V.G.; Syrotyuk, R.P.

    2016-01-01

    Probe and spectroscopic investigations of a spherical glow discharge (GD) were done in nitrogen and argon plasma. There were obtained the distributions of electron temperature and electron density in a discharge gap as well as plasma potential distribution. These results were compared with theoretical ones and the conclusion about their convergence was done in the present study. Particular attention was paid to the anode processes role in the formation of self-organized structure in a spherical glow discharge. It was shown the necessity of taking into account the possibility of the anode potential drop forming in this discharge region

  13. On the second kinetic order thermoluminescent glow curves

    International Nuclear Information System (INIS)

    Dang Thanh Luong; Nguyen Hao Quang; Hoang Minh Giang

    1995-01-01

    The kinetic parameters of thermoluminescent material such as CaF 2 -N and CaSO 4 -Dy with the different grain sizes are investigated in detail using the least square method of fitting. It was found that the activation energy E (or trap depth) and peak temperature T m ax are changed with the elapsed time between the irradiation and read-out for the low temperature glow curve peaks. The similar TL glow curve shapes are obtained for the different CaSO 4 -Dy grain size. (author). 7 refs., 5 figs., 2 tabs

  14. On open and closed field line regions in Tsyganenko's field model and their possible associations with horse collar auroras

    International Nuclear Information System (INIS)

    Birn, J.; Hones, E.W. Jr.; Craven, J.D.; Frank, L.A.; Elphinstone, R.D.; Stern, D.P.

    1991-01-01

    Using the empirical Tsyganenko (1987) long model as a prime example of a megnetospheric field model, the authors have attempted to identify the boundary between open and closed field lines. They define as closed all field lines that are connested with the Earth at both ends and cross the equatorial plane earthward of x = -70 R E , the tailward validity limit of the Tsyganenko model. They find that the form of the open/closed boundary at the Earth's surface, identified with the polar cap boundary, can exhibit the arrowhead shape, pointed toward the Sun, observed in horse collar auroras (Hones et al., 1989). The polar cap size in the Tsyganenko model increases with increasing K p values, and it becomes rounder and less pointed. The superposition of a net B y field, which is the expected consequence of an IMF B y , rotates the polar cap pattern and, for larger values, degrades the arrowhead shape, resulting in polar cap configurations consistent with known asymmetries in the aurora. The pointedness of the polar cap shape also diminishes or even completely disappears if the low-latitude magnetopause is assumed open and located considerably inside of the outermost magnetic flux surface in the Tsyganenko model. The arrowhead shape of the polar cap is found to be associated with a strong increase of B z from midnight toward the tail flanks, which is observed independently, and is possibly related to the NBZ field-aligned current system, observed during quiet times and strongly northward IMF B z . The larger B z values near the flanks of the tail cause more magnetic flux to close through these regions than through the midnight equatorial region

  15. TV morphology of some episodes of pulsating auroras

    International Nuclear Information System (INIS)

    Vallance Jones, A.; Gattinger, R.L.

    1981-01-01

    Sets of all-sky TV images of pulsating auroras obtained during the displays through which the sounding rockets of the Pulsating Aurora Campaign were fired are presented and discussed. It is emphasized that these displays are considerably more complex and variable than might seem to be the case on the basis of zenith photometer records. The pulsation modulation pattern was observed to be travelling westward during the first flight; later in the same display this apparent motion ceased. For the second flight the pulsation modulation pattern was almost stationary. (auth)

  16. Monitoring magnetosheath-magnetosphere interconnection topology from the aurora

    Directory of Open Access Journals (Sweden)

    P. E. Sandholt

    Full Text Available A strong southward rotation of the IMF (BZ from 5 to -6 nT in ~ 20 s on 4 January 1995 caused an abrupt reconfiguration of midday aurorae and plasma convection consisting of the following: (1 the red-line aurora associated with magnetosheath plasma transfer at the low-latitude magnetopause appeared at the same time that (2 the green-line aurora from precipitating energetic plasma sheet particles equatorward of the cusp (near the open-closed field line boundary weakened visibly and shifted equatorward, (3 the high-latitude aurora during the previous northward IMF, which is associated with lobe reconnection, persisted briefly (3 min and brightened, before it disappeared from the field-of-view, (4 the activation of a strong convection bay (DPY current at cusp and sub-cusp latitudes when the field turned strongly south, (5 a distinct wave motion of the plasma sheet outer boundary, as inferred from the aurora, which correlates closely with Pc 5 magnetic pulsations. Our interpretation of the dramatic reconfiguration is that reconnection poleward of the cusp coexisted briefly with reconnection at sub-cusp latitudes. The latter provided a magnetic field connection which enabled, on the one hand, magnetosheath particles to enter and cause the red-line cusp aurora, and on the other hand, allowed for magnetospheric energetic particles to escape and weaken the outer plasma sheet source of the green-line emission. The coexistence of the two cusp auroras reflects the time required for one field line topology to replace another, which, under the prevailing high speed wind ( ~ 650 km/s, lasts ~ 3–4 min. The motion of open flux tubes propagating from equator to pole during this transition is traced in the aurora by a poleward moving form. The waves on the outer boundary of the plasma sheet are most likely due to the Kelvin-Helmholtz instability. The study illustrates the ability of local auroral observations to monitor even a global change in

  17. Variation of Jupiter's Aurora Observed by Hisaki/EXCEED: 3. Volcanic Control of Jupiter's Aurora

    Science.gov (United States)

    Tao, Chihiro; Kimura, Tomoki; Tsuchiya, Fuminori; Muirakami, Go; Yoshioka, Kazuo; Yamazaki, Atsushi; Badman, Sarah V.; Misawa, Hiroaki; Kita, Hajime; Kasaba, Yasumasa; Yoshikawa, Ichiro; Fujimoto, Masaki

    2018-01-01

    Temporal variation of Jupiter's northern aurora during enhanced Io volcanic activity was detected using the EXCEED spectrometer on board the Hisaki Earth-orbiting planetary space telescope. It was found that in association with reported Io volcanic events in early 2015, auroral power and estimated field-aligned currents were enhanced during day of year 40-120. Furthermore, the far ultraviolet color ratio decreased during the event, indicating a decrease of auroral electron mean energy and total acceleration by <30%. During the episode of enhanced Io volcanic activity, Jupiter's magnetosphere contains more source current via increased suprathermal plasma density by up to 42%; therefore, it would have required correspondingly less electron acceleration to maintain the enhanced field-aligned current and corotation enforcement current. Sporadic large enhancements in auroral emission detected more frequently during the active period could have been contributed by nonadiabatic magnetospheric energization.

  18. Expression of aurora kinases: Predictor of tumor dissemination in uterine carcinosarcoma.

    Science.gov (United States)

    Han, Kyung Hee; Kim, Min A; Park, Noh Hyun

    2017-07-01

    Uterine carcinosarcoma is a rare, aggressive, and biphasic tumor. It comprises carcinomatous and sarcomatous components, and mitosis-associated factors are thought to discriminate these two lesions. Aurora kinases are mitotic enzymes that are highly expressed in uterine malignancies. To identify the clinical significance of aurora kinase expression, we performed immunohistochemistry on tissue microarrays using cores selected from areas with typical carcinomatous and sarcomatous characteristics. A total of 24 samples were included, from patients at Seoul National University Hospital diagnosed with uterine carcinosarcoma, and who undergone a staging operation between 1997 and 2012. Patients' clinical and pathological data were analyzed, and expression patterns of aurora kinases were investigated. Aurora kinases A and B were dominantly expressed in the cytoplasm, and phospho-aurora kinases A and B were expressed in the nuclei. Phospho-aurora kinase A and aurora kinase B showed significantly higher expression in the carcinomatous component (P=0.012 and 0.008). High expression of phospho-aurora kinase A was associated with lymphatic metastasis such as positive pelvic lymph node and omental involvement (P=0.012 and 0.037). Overexpression of aurora kinase B was related to vascular invasion (P=0.011). High expression of both phospho-aurora kinase A and aurora kinase B was a prognostic factor for progression-free survival in uterine carcinosarcoma (P=0.049). In conclusion, expression of aurora kinases is associated with bidirectional tumor dissemination into the lymphatic and hematogenous pathways. In addition, high expression of phospho-aurora kinase A and aurora kinase B is a predictor of progression-free survival. Therefore, inhibitors of aurora kinases might be a prospective therapeutic options for uterine carcinosarcoma.

  19. Antitumor activity of TY-011 against gastric cancer by inhibiting Aurora A, Aurora B and VEGFR2 kinases

    Directory of Open Access Journals (Sweden)

    Wang Liu

    2016-11-01

    Full Text Available Abstract Background Overexpression of Aurora A and B has been reported in a wide range of tumor types, including gastric cancer. Anti-angiogenesis has been considered as an important therapeutic modality in advanced gastric cancer. Here we identified a novel compound TY-011 with promising antitumor activity by targeting mitotic kinases (Aurora A and B and angiogenic receptor tyrosine kinase (VEGFR2. Methods HTRF® KinEASE™ assay was used to detect the effect of TY-011 against Aurora A, Aurora B and VEGFR2 activities. Docking simulation study was performed to predict the binding mode of TY-011 with Aurora A and B kinases. CCK-8 assay was used to test cell growth. Cell cycle and cell apoptosis was analyzed by flow cytometry. Gastric cancer cell xenograft mouse models were used for in vivo study. TUNEL kit was used to determine the apoptosis of tumor tissues. Immunohistochemistry analysis and HUVEC tube formation assay were performed to determine the anti-angiogenesis ability. Immunofluorescence and western blot were used to test protein expression. Results TY-011 was identified as a potential Aurora A and B inhibitor by HTRF® KinEASE™ assay. It effectively inhibited cellular Aurora A and B activities in a concentration-dependent manner. TY-011 occupied the ATP-binding site of both Aurora A and B kinases. TY-011 demonstrated prominent inhibitory effects on proliferation of gastric cancer cells. TY-011 treatment induced an obvious accumulation of cells at G2/M phase and a modest increase of cells with >4 N DNA content, which then underwent apoptosis. Meaningfully, orally administration of TY-011 demonstrated superior efficacy against the tumor growth in gastric cancer cell xenograft, with ~90% inhibition rate and 100% tumor regression at 9 mg/kg dose, and TY-011 did not affect the body weight of mice. Interestingly, we observed that TY-011 also antagonized tumor angiogenesis by targeting VEGFR2 kinase. Conclusions These results indicate that

  20. The ion experiment onboard the Interball-Aurora satellite; initial results on velocity-dispersed structures in the cleft and inside the auroral oval

    Directory of Open Access Journals (Sweden)

    J. A. Sauvaud

    1998-09-01

    Full Text Available The Toulouse ION experiment flown on the Russian Interball-Aurora mission performs simultaneous ion and electron measurements. Two mass spectrometers looking in opposing directions perpendicular to the satellite spin axis, which points toward the sun, measure ions in the mass and energy ranges 1–32 amu and ~0–14 000 eV. Two electron spectrometers also looking in opposing directions perform measurements in the energy range ~10 eV–20 000 eV. The Interball-Aurora spacecraft was launched on 29 August 1996 into a 62.8° inclination orbit with an apogee of ~3 RE. The satellite orbital period is 6 h, so that every four orbits the satellite sweeps about the same region of the auroral zone; the orbit plane drifts around the pole in ~9 months. We present a description of the ION experiment and discuss initial measurements performed in the cusp near noon, in the polar cleft at dusk, and inside the proton aurora at dawn. Ion-dispersed energy structures resulting from time-of-flight effects are observed both in the polar cleft at ~16 hours MLT and in the dawnside proton aurora close to 06 hours MLT. Magnetosheath plasma injections in the polar cleft, which appear as overlapping energy bands in particle energy-time spectrograms, are traced backwards in time using a particle trajectory model using 3D electric and magnetic field models. We found that the cleft ion source is located at distances of the order of 18 RE from the earth at about 19 MLT, i.e., on the flank of the magnetopause. These observations are in agreement with flux transfer events (FTE occurring not only on the front part of the magnetopause but also in a region extending at least to dusk. We also show that, during quiet magnetic conditions, time-of-flight ion dispersions can also be measured inside the dawn proton aurora. A method similar to that used for the cleft is applied to these auroral energy dispersion signatures. Unexpectedly, the ion source is found to be at distances of the

  1. The ion experiment onboard the Interball-Aurora satellite; initial results on velocity-dispersed structures in the cleft and inside the auroral oval

    Directory of Open Access Journals (Sweden)

    J. A. Sauvaud

    Full Text Available The Toulouse ION experiment flown on the Russian Interball-Aurora mission performs simultaneous ion and electron measurements. Two mass spectrometers looking in opposing directions perpendicular to the satellite spin axis, which points toward the sun, measure ions in the mass and energy ranges 1–32 amu and ~0–14 000 eV. Two electron spectrometers also looking in opposing directions perform measurements in the energy range ~10 eV–20 000 eV. The Interball-Aurora spacecraft was launched on 29 August 1996 into a 62.8° inclination orbit with an apogee of ~3 RE. The satellite orbital period is 6 h, so that every four orbits the satellite sweeps about the same region of the auroral zone; the orbit plane drifts around the pole in ~9 months. We present a description of the ION experiment and discuss initial measurements performed in the cusp near noon, in the polar cleft at dusk, and inside the proton aurora at dawn. Ion-dispersed energy structures resulting from time-of-flight effects are observed both in the polar cleft at ~16 hours MLT and in the dawnside proton aurora close to 06 hours MLT. Magnetosheath plasma injections in the polar cleft, which appear as overlapping energy bands in particle energy-time spectrograms, are traced backwards in time using a particle trajectory model using 3D electric and magnetic field models. We found that the cleft ion source is located at distances of the order of 18 RE from the earth at about 19 MLT, i.e., on the flank of the magnetopause. These observations are in agreement with flux transfer events (FTE occurring not only on the front part of the magnetopause but also in a region extending at least to dusk. We also show that, during quiet magnetic conditions, time-of-flight ion dispersions can also be measured inside the dawn proton aurora. A method similar to that used for the cleft is applied to these auroral energy dispersion signatures. Unexpectedly, the ion source is found to be

  2. Generation of uniform atmospheric pressure argon glow plasma by ...

    Indian Academy of Sciences (India)

    Vol. 80, No. 3. — journal of. March 2013 physics pp. 507–517. Generation of uniform atmospheric pressure argon glow plasma by dielectric barrier discharge .... note that the change in current waveform is also due to the change in capacitance of the ... By taking the ratio of R1 and R2 we then obtain the expression: R1. R2.

  3. Generation of uniform atmospheric pressure argon glow plasma by ...

    Indian Academy of Sciences (India)

    In this paper, atmospheric pressure glow discharges (APGD) in argon generated in parallel plate dielectric barrier discharge system is investigated by means of electrical and optical measurements. Using a high voltage (0–20 kV) power supply operating at 10–30 kHz, homogeneous and steady APGD has been observed ...

  4. Hydrogen and deuterium incorporation in glow discharge amorphous silicon

    NARCIS (Netherlands)

    Maessen, K.M.H.; Pruppers, M.J.M.; Habraken, F.H.P.M.; Bezemer, J.; Weg, W.F. van der

    1985-01-01

    The incorporation of hydrogen in glow discharge a-Si:H is investigated with an isotope method. During deposition D2 or H2 is added to the silane. Although for low silane flow the incorporation of deuterium is affected by isotope exchange this process plays a minor role for high silane flow. At these

  5. An algorithm for unified analysis on the thermoluminescence glow curve

    International Nuclear Information System (INIS)

    Chung, K.S.; Park, C.Y.; Lee, J.I.; Kim, J.L.

    2014-01-01

    An algorithm was developed to integrally handle excitation by radiation, relaxation and luminescence by thermal or optical stimulation in thermoluminescence (TL) and optically stimulated luminescence (OSL) processes. This algorithm reflects the mutual interaction between traps through a conduction band. Electrons and holes are created by radiation in the beginning, and these electrons move to the trap through the conduction band. These holes move to the recombination center through a valence band. The ratio of the electrons allocated to each trap differs with the recombination probability and these values also relevant to the process of luminescence. Accordingly, the glow curve can be interpreted by taking the rate of electron–hole pairs created by ionizing radiation as a unique initial condition. This method differs from the conventional method of interpreting the measured glow curve with the initial electron concentration allocated to each trap at the end of irradiation. A program using the Visual Studio's C# subsystem was made to realize such a developed algorithm. To verify this algorithm it was applied to LiF:Mg,Cu,Si. The TL glow curve was deconvoluted with a model of five traps, one deep trap and one recombination center (RC). - Highlights: • TL glow curve deconvolution employing interacting model. • Simulation both irradiation and TL readout stages for various dose level. • Application in the identification TL kinetics of LiF:Mg,Cu,Si TLD

  6. Time dependent argon glow discharge treatment of Al-alloy

    Indian Academy of Sciences (India)

    All the applications of non-equilibrium plasmas involve processes like sputtering, etching, polynterization, surface modifications, etc. The glow discharge conditioning (GDC) has become the final and essential stage of surface conditioning process of vacuum vessels of particle accelerators, storage rings and toka- maks [5].

  7. Genetic diversity in two populations of Limicolaria aurora (Jay, 1839 ...

    African Journals Online (AJOL)

    Tuoyo Aghomotsegin

    2016-06-22

    Jun 22, 2016 ... savannah) and Benin City (tropical rain forest) in Nigeria and possibly delimit the populations into sub species. A total of one hundred and ten specimens of L. aurora made up ..... Environmental stress such as drought could possibly have influenced genetic diversity in New Bussa with lower annual rainfall ...

  8. Nutritive potentials and utilization of garden snail (Limicolaria aurora ...

    African Journals Online (AJOL)

    The possibility of using garden snail (Limicolaria aurora) meat meal as a protein source in fish feeds was tested in Clarias gariepinus fingerlings. Five isonitrogenous (43% crude protein) diets in which garden snail meat meal was used to replace fish meal at 0%, (control diet), 25, 50, 75 and 100% inclusion levels were used ...

  9. Study of short atmospheric pressure dc glow microdischarge in air

    Science.gov (United States)

    Kudryavtsev, Anatoly; Bogdanov, Eugene; Chirtsov, Alexander; Emelin, Sergey

    2011-10-01

    The results of experiments and simulations of short (without positive column) atmospheric pressure dc glow discharge in air are presented. We used metal steel electrodes with a gap of 5-100 microns. The experimental voltage-current characteristic's (VAC) have a constant or slightly increasing form at low gap. The most stable microdischarges were burning with a flat cathode and rounded anode, when the length of the discharge is automatically established near the minimum of the Paschen curve by changing their binding on the anode. In this case microdischarge was stable and it had growing VAC. For simulations we used 2D fluid model with kinetic description of electrons. We solved the balance equations for the vibrationally- and the electronically-excited states of a nitrogen and oxygen molecules; nitrogen and oxygen atoms; ozone molecule; and different nitrogen and oxygen ions with different plasmochemical reactions between them. Simulations predicted the main regions of the dc glow discharges including cathode and anode sheath and plasma of negative glow, Faraday dark space and transition region. Gas heating plays an important role in shaping the discharge profiles. The results of experiments and simulations of short (without positive column) atmospheric pressure dc glow discharge in air are presented. We used metal steel electrodes with a gap of 5-100 microns. The experimental voltage-current characteristic's (VAC) have a constant or slightly increasing form at low gap. The most stable microdischarges were burning with a flat cathode and rounded anode, when the length of the discharge is automatically established near the minimum of the Paschen curve by changing their binding on the anode. In this case microdischarge was stable and it had growing VAC. For simulations we used 2D fluid model with kinetic description of electrons. We solved the balance equations for the vibrationally- and the electronically-excited states of a nitrogen and oxygen molecules; nitrogen

  10. Microtubules Accelerate the Kinase Activity of Aurora-B by a Reduction in Dimensionality

    Science.gov (United States)

    Noujaim, Michael; Bechstedt, Susanne; Wieczorek, Michal; Brouhard, Gary J.

    2014-01-01

    Aurora-B is the kinase subunit of the Chromosome Passenger Complex (CPC), a key regulator of mitotic progression that corrects improper kinetochore attachments and establishes the spindle midzone. Recent work has demonstrated that the CPC is a microtubule-associated protein complex and that microtubules are able to activate the CPC by contributing to Aurora-B auto-phosphorylation in trans. Aurora-B activation is thought to occur when the local concentration of Aurora-B is high, as occurs when Aurora-B is enriched at centromeres. It is not clear, however, whether distributed binding to large structures such as microtubules would increase the local concentration of Aurora-B. Here we show that microtubules accelerate the kinase activity of Aurora-B by a “reduction in dimensionality.” We find that microtubules increase the kinase activity of Aurora-B toward microtubule-associated substrates while reducing the phosphorylation levels of substrates not associated to microtubules. Using the single molecule assay for microtubule-associated proteins, we show that a minimal CPC construct binds to microtubules and diffuses in a one-dimensional (1D) random walk. The binding of Aurora-B to microtubules is salt-dependent and requires the C-terminal tails of tubulin, indicating that the interaction is electrostatic. We show that the rate of Aurora-B auto-activation is faster with increasing concentrations of microtubules. Finally, we demonstrate that microtubules lose their ability to stimulate Aurora-B when their C-terminal tails are removed by proteolysis. We propose a model in which microtubules act as scaffolds for the enzymatic activity of Aurora-B. The scaffolding activity of microtubules enables rapid Aurora-B activation and efficient phosphorylation of microtubule-associated substrates. PMID:24498282

  11. Microtubules accelerate the kinase activity of Aurora-B by a reduction in dimensionality.

    Science.gov (United States)

    Noujaim, Michael; Bechstedt, Susanne; Wieczorek, Michal; Brouhard, Gary J

    2014-01-01

    Aurora-B is the kinase subunit of the Chromosome Passenger Complex (CPC), a key regulator of mitotic progression that corrects improper kinetochore attachments and establishes the spindle midzone. Recent work has demonstrated that the CPC is a microtubule-associated protein complex and that microtubules are able to activate the CPC by contributing to Aurora-B auto-phosphorylation in trans. Aurora-B activation is thought to occur when the local concentration of Aurora-B is high, as occurs when Aurora-B is enriched at centromeres. It is not clear, however, whether distributed binding to large structures such as microtubules would increase the local concentration of Aurora-B. Here we show that microtubules accelerate the kinase activity of Aurora-B by a "reduction in dimensionality." We find that microtubules increase the kinase activity of Aurora-B toward microtubule-associated substrates while reducing the phosphorylation levels of substrates not associated to microtubules. Using the single molecule assay for microtubule-associated proteins, we show that a minimal CPC construct binds to microtubules and diffuses in a one-dimensional (1D) random walk. The binding of Aurora-B to microtubules is salt-dependent and requires the C-terminal tails of tubulin, indicating that the interaction is electrostatic. We show that the rate of Aurora-B auto-activation is faster with increasing concentrations of microtubules. Finally, we demonstrate that microtubules lose their ability to stimulate Aurora-B when their C-terminal tails are removed by proteolysis. We propose a model in which microtubules act as scaffolds for the enzymatic activity of Aurora-B. The scaffolding activity of microtubules enables rapid Aurora-B activation and efficient phosphorylation of microtubule-associated substrates.

  12. Aurora-A interacts with AP-2α and down regulates its transcription activity.

    Directory of Open Access Journals (Sweden)

    Lihui Zou

    Full Text Available Aurora-A is a serine/threonine protein kinase and plays an important role in the control of mitotic progression. Dysregulated expression of Aurora-A impairs centrosome separation and maturation, which lead to disrupted cell cycle progression and tumorigenesis. However, the molecular mechanism by which Aurora-A causes cell malignant transformation remains to be further defined. In this report, using transcription factors array and mRNA expression profiling array, we found that overexpression of Aurora-A suppressed transcription activity of AP-2α, a tumor suppressor that is often downregulated in variety of tumors, and inhibited expression of AP-2α-regulated downstream genes. These array-based observations were further confirmed by microwell colorimetric TF assay and luciferase reporter assay. Downregulated transcription activity of AP-2α by Aurora-A was found to be associated with reduced AP-2α protein stability, which appeared to be mediated by Aurora-A enhanced ubiquitin-dependent proteasomal degradation of AP-2α protein. Interestingly, Aurora-A-mediated AP-2α degradation was likely dependent Aurora-A kinase activity since inhibition of Aurora-A kinase activity was able to rescue Aurora-A-induced degradation of AP-2α. Moreover, we defined a physical interaction between Aurora-A and AP-2α, and such interaction might bridge the suppressive effect of Aurora-A on AP-2α protein stability. These findings provide new insights into molecular mechanism by which Aurora-A acts as an oncogenic molecule in tumor occurrence and malignant development.

  13. Microtubules accelerate the kinase activity of Aurora-B by a reduction in dimensionality.

    Directory of Open Access Journals (Sweden)

    Michael Noujaim

    Full Text Available Aurora-B is the kinase subunit of the Chromosome Passenger Complex (CPC, a key regulator of mitotic progression that corrects improper kinetochore attachments and establishes the spindle midzone. Recent work has demonstrated that the CPC is a microtubule-associated protein complex and that microtubules are able to activate the CPC by contributing to Aurora-B auto-phosphorylation in trans. Aurora-B activation is thought to occur when the local concentration of Aurora-B is high, as occurs when Aurora-B is enriched at centromeres. It is not clear, however, whether distributed binding to large structures such as microtubules would increase the local concentration of Aurora-B. Here we show that microtubules accelerate the kinase activity of Aurora-B by a "reduction in dimensionality." We find that microtubules increase the kinase activity of Aurora-B toward microtubule-associated substrates while reducing the phosphorylation levels of substrates not associated to microtubules. Using the single molecule assay for microtubule-associated proteins, we show that a minimal CPC construct binds to microtubules and diffuses in a one-dimensional (1D random walk. The binding of Aurora-B to microtubules is salt-dependent and requires the C-terminal tails of tubulin, indicating that the interaction is electrostatic. We show that the rate of Aurora-B auto-activation is faster with increasing concentrations of microtubules. Finally, we demonstrate that microtubules lose their ability to stimulate Aurora-B when their C-terminal tails are removed by proteolysis. We propose a model in which microtubules act as scaffolds for the enzymatic activity of Aurora-B. The scaffolding activity of microtubules enables rapid Aurora-B activation and efficient phosphorylation of microtubule-associated substrates.

  14. IQGAP1 interacts with Aurora-A and enhances its stability and its role in cancer

    International Nuclear Information System (INIS)

    Yin, Ning; Shi, Ji; Wang, Dapeng; Tong, Tong; Wang, Mingrong; Fan, Feiyue; Zhan, Qimin

    2012-01-01

    Highlights: ► IQGAP1 interacts with Aurora-A through its RGCt domain. ► Overexpression of IQGAP1 prevents ubiquitination of Aurora-A. ► Overexpression of IQGAP1 enhances the protein stability of Aurora-A. ► Overexpression of IQGAP1 promotes the kinase activity of Aurora-A. -- Abstract: IQGAP1, a ubiquitously expressed scaffold protein, has been identified in a wide range of organisms. It participates in multiple aspects of cellular events by binding to and regulating numerous interacting proteins. In our present study, we identified a new IQGAP1 binding protein named Aurora-A which is an oncogenic protein and overexpressed in various types of human tumors. In vitro analysis with GST-Aurora-A fusion proteins showed a physical interaction between Aurora-A and IQGAP1. Moreover, the binding also occurred in HeLa cells as endogenous Aurora-A co-immunoprecipitated with IQGAP1 from the cell lysates. Overexpression of IQGAP1 resulted in an elevation of both expression and activity of Aurora-A kinase. Endogenous IQGAP1 knockdown by siRNA promoted Aurora-A degradation whereas IQGAP1 overexpression enhanced the stability of Aurora-A. Additionally, we documented that the IQGAP1-induced cell proliferation was suppressed by knocking down Aurora-A expression. Taken together, our results showed an unidentified relationship between Aurora-A and IQGAP1, and provided a new insight into the molecular mechanism by which IQGAP1 played a regulatory role in cancer.

  15. World first complex optical instrumental observations of aurora in the Arctic in 1899−1900

    Directory of Open Access Journals (Sweden)

    S. A. Chernouss

    2005-07-01

    Full Text Available This report presents data and analysis of visual, photographic and auroral spectral data, obtained by the Russian astronomer J. Sykora from the Russian-Swedish expedition to Spitsbergen during the 1899–1900 winter season, which are historically significant for auroral studies. These data seem to be the first instrumental observations of auroral spectra in the Arctic and some of the emissions discovered have world priority. The second known photos in the world of aurora from the Arctic and undoubtedly the first ones for geomagnetic latitudes of about 75° in the Spitsbergen Archipelago were obtained. The results of the expedition are discussed from a modern point of view and compared with our knowledge of the 21st century. A description of the equipment and methods that were used by Russian astronomers is presented. Both photographic and spectral devices using registration by photographic plates were used, along with special methods of their development and enhancement. Some statistical analysis was done on the basis of the expedition reports and diaries. This analysis shows that by using Sykora's data it was possible to discover the auroral oval or instantaneous auroral distribution over the polar region. Analysis of photographic samples and sketches of the aurora demonstrate typical auroral form outlines as they are described today. Spectral plates exposed for several hours to auroral lights revealed not only the main auroral emissions, which were well-known at that time, but several other unidentified weak emissions, which were rediscovered and interpreted years later. Keywords. History of geophysics (Atmospheric sciences, instruments and techniques

  16. Dust particle charge distribution in a stratified glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Sukhinin, Gennady I [Institute of Thermophysics, Siberian Branch, Russian Academy of Sciences, Lavrentyev Ave., 1, Novosibirsk 630090 (Russian Federation); Fedoseev, Alexander V [Institute of Thermophysics, Siberian Branch, Russian Academy of Sciences, Lavrentyev Ave., 1, Novosibirsk 630090 (Russian Federation); Ramazanov, Tlekkabul S [Institute of Experimental and Theoretical Physics, Al Farabi Kazakh National University, Tole Bi, 96a, Almaty 050012 (Kazakhstan); Dzhumagulova, Karlygash N [Institute of Experimental and Theoretical Physics, Al Farabi Kazakh National University, Tole Bi, 96a, Almaty 050012 (Kazakhstan); Amangaliyeva, Rauan Zh [Institute of Experimental and Theoretical Physics, Al Farabi Kazakh National University, Tole Bi, 96a, Almaty 050012 (Kazakhstan)

    2007-12-21

    The influence of a highly pronounced non-equilibrium characteristic of the electron energy distribution function in a stratified dc glow discharge on the process of dust particle charging in a complex plasma is taken into account for the first time. The calculated particle charge spatial distribution is essentially non-homogeneous and it can explain the vortex motion of particles at the periphery of a dusty cloud obtained in experiments.

  17. The Use of DC Glow Discharges as Undergraduate Educational Tools

    Energy Technology Data Exchange (ETDEWEB)

    Stephanie A. Wissel and Andrew Zwicker, Jerry Ross, and Sophia Gershman

    2012-10-09

    Plasmas have a beguiling way of getting students excited and interested in physics. We argue that plasmas can and should be incorporated into the undergraduate curriculum as both demonstrations and advanced investigations of electromagnetism and quantum effects. Our device, based on a direct current (DC) glow discharge tube, allows for a number of experiments into topics such as electrical breakdown, spectroscopy, magnetism, and electron temperature.

  18. Aurora-A regulates MCRS1 function during mitosis.

    Science.gov (United States)

    Meunier, Sylvain; Timón, Krystal; Vernos, Isabelle

    2016-07-02

    The mitotic spindle is made of microtubules (MTs) nucleated through different pathways involving the centrosomes, the chromosomes or the walls of pre-existing MTs. MCRS1 is a RanGTP target that specifically associates with the chromosome-driven MTs protecting them from MT depolymerases. MCRS1 is also needed for the control of kinetochore fiber (K-fiber) MT minus-ends dynamics in metaphase. Here, we investigated the regulation of MCRS1 activity in M-phase. We show that MCRS1 is phosphorylated by the Aurora-A kinase in mitosis on Ser35/36. Although this phosphorylation has no role on MCRS1 localization to chromosomal MTs and K-fiber minus-ends, we show that it regulates MCRS1 activity in mitosis. We conclude that Aurora-A activity is particularly important in the tuning of K-fiber minus-ends dynamics in mitosis.

  19. Planetary protection in the framework of the Aurora exploration program

    Science.gov (United States)

    Kminek, G.

    The Aurora Exploration Program will give ESA new responsibilities in the field of planetary protection. Until now, ESA had only limited exposure to planetary protection from its own missions. With the proposed ExoMars and MSR missions, however, ESA will enter the realm of the highest planetary protection categories. As a consequence, the Aurora Exploration Program has initiated a number of activities in the field of planetary protection. The first and most important step was to establish a Planetary Protection Working Group (PPWG) that is advising the Exploration Program Advisory Committee (EPAC) on all matters concerning planetary protection. The main task of the PPWG is to provide recommendations regarding: Planetary protection for robotic missions to Mars; Planetary protection for a potential human mission to Mars; Review/evaluate standards & procedures for planetary protection; Identify research needs in the field of planetary protection. As a result of the PPWG deliberations, a number of activities have been initiated: Evaluation of the Microbial Diversity in SC Facilities; Working paper on legal issues of planetary protection and astrobiology; Feasibility study on a Mars Sample Return Containment Facility; Research activities on sterilization procedures; Training course on planetary protection (May, 2004); Workshop on sterilization techniques (fall 2004). In parallel to the PPWG, the Aurora Exploration Program has established an Ethical Working Group (EWG). This working group will address ethical issues related to astrobiology, planetary protection, and manned interplanetary missions. The recommendations of the working groups and the results of the R&D activities form the basis for defining planetary protection specification for Aurora mission studies, and for proposing modification and new inputs to the COSPAR planetary protection policy. Close cooperation and free exchange of relevant information with the NASA planetary protection program is strongly

  20. Aurora kinase A controls meiosis I progression in mouse oocytes

    Czech Academy of Sciences Publication Activity Database

    Šašková, Adéla; Šolc, Petr; Baran, V.; Kubelka, Michal; Schultz, R. M.; Motlík, Jan

    2008-01-01

    Roč. 7, č. 15 (2008), s. 2368-2376 ISSN 1538-4101 R&D Projects: GA ČR GA305/06/1413; GA ČR GD204/05/H023 Institutional research plan: CEZ:AV0Z50450515 Keywords : aurora-A * MTOC * CDK1 Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.120, year: 2008 www.landesbioscience.com/journals/cc/article/6361

  1. Measurement of the electrostatic field in aurora by antarctic rocket

    International Nuclear Information System (INIS)

    Takeya, Yoshio; Minami, Shigeyuki

    1974-01-01

    The direct measurement of the electrostatic field produced by the flow of charged particles and geomagnetic field in aurora has been carried out by means of rockets or satellites. The construction of an electric field meter and its characteristics are described, which measures the vectors of electric field with antarctic rockets. New scheme is presented: three components of an electric field are directly obtained through the probes set in three directions. (Mori, K.)

  2. Control system for compact SR light source 'AURORA'

    International Nuclear Information System (INIS)

    Fukami, Nobutaka; Kariya, Hiroyuki; Yamada, Hironari

    1991-01-01

    The computer control system developed for 'AURORA' has a three level hierarchical architecture. The top level is Central Intelligence System (CIS), and the second one is Autonomic Control System (ACS). The bottom one is an assembly of distributed local controllers linked to the ACS level through optical fibers. This system provides fully automated operation, and a powerful machine study capability through the associated man-machine console and an interpretive operation language. (author)

  3. Performance of the Aurora KrF ICF laser system

    International Nuclear Information System (INIS)

    Jones, J.E.; Czuchlewski, S.J.; Turner, T.P.; Watt, R.G.; Thomas, S.J.; Netz, D.A.; Tallman, C.R.; Mack, J.M.; Figueira, J.F.

    1990-01-01

    Because short wavelength lasers are attractive for inertial confinement fusion (ICF), the Department of Energy is sponsoring work at Los Alamos National Laboratory in krypton-fluoride (KrF) laser technology. Aurora is a short-pulse, high-power, KrF laser system. It serves as an end-to-end technology demonstration prototype for large-scale ultraviolet laser systems for short wavelength ICF research. The system employs optical angular multiplexing and serial amplification by electron-beam-driven KrF laser amplifiers. The 1 to 5 ns pulse of the Aurora front end is split into 96 beams which are angularly and temporally multiplexed to produce a 480 ns pulse train for amplification by four KrF laser amplifiers. In the present system configuration half (48) of the amplified pulses are demultiplexed using different optical path lengths and delivered simultaneously to target. This paper discusses how the Aurora laser system has entered the initial operational phase by delivering pulse energies of greater than one kilojoule to target

  4. Ionospheric electron heating associated with pulsating auroras: A Swarm survey and model simulation

    Science.gov (United States)

    Liang, Jun; Yang, B.; Donovan, E.; Burchill, J.; Knudsen, D.

    2017-08-01

    In this paper we report a study on the plasma signatures (electron temperature, plasma density, and field-aligned current) of patchy pulsating auroras in the upper F region ionosphere using Swarm satellite data. Via a survey of 38 patch crossing events, we repeatedly identify a strong electron temperature enhancement associated with the pulsating aurora. On average, the electron temperature at Swarm satellite altitudes ( 460 km) increases from 2200 K at subauroral latitudes to a peak of 3000 K within the pulsating auroral patch. This indicates that pulsating auroras may act as an important heating source for the nightside ionosphere. On the other hand, no well-defined trend of plasma density variations associated with pulsating auroras is identified at Swarm altitudes. The field-aligned currents within the pulsating aurora patch are mostly upward, with mean magnitudes on order of 1 μA/m2. We then perform a numerical simulation to explore the potential mechanisms underlying the strong electron heating associated with the pulsating aurora. Via simulations we find that to account for the realistic electron temperature observation in a major portion of our events, pulsating auroras are likely accompanied by substantial magnetospheric heat fluxes around the order of 1010 eV/cm2. We propose that such magnetospheric heat fluxes may be pertinent to one long-hypothesized feature of pulsating auroras, namely, the coexistence of an enhanced low-energy plasma population in magnetic flux tubes threading the pulsating aurora, in addition to the energetic electron precipitation. Via a Swarm survey we repeatedly find a strong electron temperature enhancement associated with the pulsating aurora The field-aligned currents within pulsating auroras are moderately upward, with mean magnitudes on the order of 1e-6 A/m2 To explain the observed electron heating, pulsating auroras are likely accompanied by magnetospheric heat fluxes around 1E+10 eV/cm2/s.

  5. Aurora kinase inhibition induces PUMA via NF-κB to kill colon cancer cells

    Science.gov (United States)

    Sun, Jing; Knickelbein, Kyle; He, Kan; Chen, Dongshi; Dongshi, Crissy; Shu, Yongqian; Yu, Jian; Zhang, Lin

    2014-01-01

    Aurora kinases play a key role in mitosis and are frequently overexpressed in a variety of tumor cells. Inhibition of aurora kinases results in mitotic arrest and death of cancer cells, and has been explored as an anticancer strategy. However, how aurora inhibition kills cancer cells is poorly understood. In this study, we found that inhibition of aurora kinases by siRNA or small-molecule inhibitors led to induction of PUMA, a BH3-only Bcl-2 family protein, in colorectal cancer cells irrespective of p53 status. Deficiency in PUMA increased polyploidy, improved cell survival, and abrogated mitochondria-mediated apoptosis induced by aurora kinase inhibitors. In response to aurora kinase inhibition, PUMA was directly activated by p65 through the canonical NF-κB pathway following AKT inhibition. Furthermore, PUMA was necessary for the chemosensitization and in vivo antitumor effects of aurora kinase inhibitors in colon cancer cells. These results suggest that PUMA induction mediates the apoptotic response to mitotic arrest imposed by aurora kinase inhibition, and may be a useful indicator for the anticancer activity of aurora kinase inhibitors. PMID:24563542

  6. Classification of Aurora kinase inhibitors by self-organizing map (SOM) and support vector machine (SVM).

    Science.gov (United States)

    Yan, Aixia; Nie, Xianglei; Wang, Kai; Wang, Maolin

    2013-03-01

    The Aurora kinase family (consisting of Aurora-A, -B and -C) is an important group of enzymes that controls several aspects of cell division in mammalian cells. In this study, 512 compounds of Aurora-A and -B inhibitors were collected. They were classified into three classes: dual Aurora-A and Aurora-B inhibitors, selective inhibitors of Aurora-A and selective inhibitors of Aurora-B by Self-Organizing Map (SOM) and Support Vector Machine (SVM). The prediction accuracies of the models (based on the training/test set splitting using SOM method) for the test set were 92.2% for SOM1 and 93.8% for SVM1, respectively. In addition, the extended connectivity fingerprints (ECFP_4) for all the molecules were calculated and structure-activity relationship of Aurora kinase inhibitors was summarized, which may be helpful to find the important structural features of inhibitors relating to the selectivity to Aurora kinases. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  7. Effect of the interaction among traps on the shape of thermoluminescence glow curves

    International Nuclear Information System (INIS)

    Marcazzo, J.; Santiago, M.; Spano, F.; Lester, M.; Ortega, F.; Molina, P.; Caselli, E.

    2007-01-01

    The effect of the interaction among traps on the structure of thermoluminescence glow curves has been investigated by generating numerically simulated glow curves for a wide range of trap parameters. The results reported in this paper provide useful insights which assist in the analysis of experimental glow curves. The most important result shows that it is incorrect to assume beforehand that each peak is related to a specific trapping state. The validity of the quasiequilibrium approximation is briefly discussed

  8. Polarization Optics

    OpenAIRE

    Fressengeas, Nicolas

    2010-01-01

    The physics of polarization optics *Polarized light propagation *Partially polarized light; DEA; After a brief introduction to polarization optics, this lecture reviews the basic formalisms for dealing with it: Jones Calculus for totally polarized light and Stokes parameters associated to Mueller Calculus for partially polarized light.

  9. Evolutionary relationships of Aurora kinases: Implications for model organism studies and the development of anti-cancer drugs

    Directory of Open Access Journals (Sweden)

    Patrick Denis R

    2004-10-01

    Full Text Available Abstract Background As key regulators of mitotic chromosome segregation, the Aurora family of serine/threonine kinases play an important role in cell division. Abnormalities in Aurora kinases have been strongly linked with cancer, which has lead to the recent development of new classes of anti-cancer drugs that specifically target the ATP-binding domain of these kinases. From an evolutionary perspective, the species distribution of the Aurora kinase family is complex. Mammals uniquely have three Aurora kinases, Aurora-A, Aurora-B, and Aurora-C, while for other metazoans, including the frog, fruitfly and nematode, only Aurora-A and Aurora-B kinases are known. The fungi have a single Aurora-like homolog. Based on the tacit assumption of orthology to human counterparts, model organism studies have been central to the functional characterization of Aurora kinases. However, the ortholog and paralog relationships of these kinases across various species have not been rigorously examined. Here, we present comprehensive evolutionary analyses of the Aurora kinase family. Results Phylogenetic trees suggest that all three vertebrate Auroras evolved from a single urochordate ancestor. Specifically, Aurora-A is an orthologous lineage in cold-blooded vertebrates and mammals, while structurally similar Aurora-B and Aurora-C evolved more recently in mammals from a duplication of an ancestral Aurora-B/C gene found in cold-blooded vertebrates. All so-called Aurora-A and Aurora-B kinases of non-chordates are ancestral to the clade of chordate Auroras and, therefore, are not strictly orthologous to vertebrate counterparts. Comparisons of human Aurora-B and Aurora-C sequences to the resolved 3D structure of human Aurora-A lends further support to the evolutionary scenario that vertebrate Aurora-B and Aurora-C are closely related paralogs. Of the 26 residues lining the ATP-binding active site, only three were variant and all were specific to Aurora-A. Conclusions In

  10. AURORA on MEGSAT 1 a photon counting observatory for the Earth UV night-sky background and Aurora emission

    CERN Document Server

    Monfardini, A; Stalio, R; Mahne, N; Battiston, R; Menichelli, M; Mazzinghi, P

    2001-01-01

    A low-mass, low-cost photon-counting scientific payload has been developed and launched on a commercial microsatellite in order to study the near-UV night-sky background emission with a telescope nicknamed 'Notte' and the Aurora emission with 'Alba'. AURORA, this is the name of the experiment, will determine, with the 'Notte' channel, the overall night-side photon background in the 300-400 nm spectral range, together with a particular 2 sup + N sub 2 line (lambda sub c =337 nm). The 'Alba' channel, on the other hand, will study the Aurora emissions in four different spectral bands (FWHM=8.4-9.6 nm) centered on: 367 nm (continuum evaluation), 391 nm (1 sup - N sup + sub 2), 535 nm (continuum evaluation), 560 nm (OI). The instrument has been launched on the 26 September, 2000 from the Baikonur cosmodrome on a modified SS18 Dnepr-1 'Satan' rocket. The satellite orbit is nearly circular (h sub a sub p sub o sub g sub e sub e =648 km, e=0.0022), and the inclination of the orbital plane is 64.56 deg. An overview of...

  11. Means of introducing an analyte into liquid sampling atmospheric pressure glow discharge

    Science.gov (United States)

    Marcus, R. Kenneth; Quarles, Jr., Charles Derrick; Russo, Richard E.; Koppenaal, David W.; Barinaga, Charles J.; Carado, Anthony J.

    2017-01-03

    A liquid sampling, atmospheric pressure, glow discharge (LS-APGD) device as well as systems that incorporate the device and methods for using the device and systems are described. The LS-APGD includes a hollow capillary for delivering an electrolyte solution to a glow discharge space. The device also includes a counter electrode in the form of a second hollow capillary that can deliver the analyte into the glow discharge space. A voltage across the electrolyte solution and the counter electrode creates the microplasma within the glow discharge space that interacts with the analyte to move it to a higher energy state (vaporization, excitation, and/or ionization of the analyte).

  12. A glow curve analyzer (GCA) for routine analysis of personnel thermoluminescent dosemeter results

    International Nuclear Information System (INIS)

    Chase, W.J.; Bezaire, M.D.; Vanderzwet, F.P.; Taylor, C.E.

    2008-01-01

    A glow curve analyzer (GCA) spreadsheet has been developed using Microsoft Excel to perform glow curve analysis on thermoluminescent dosimeter (TLD) data from a personnel dosimetry system. The TLD data come from cards with four LiF:Mg,Ti chips that have been annealed and therefore have a simple glow peak structure. GCA removes spikes in the glow curve data, and then smoothes it. After select start and end points for the glow peak, it fits a Boltzmann function to represent the glow curve signal background under the glow peak. The Boltzmann function is subtracted and two Weibull curves are fit to the remaining net signal between the start and end points. The first Weibull curve is fit to peak 5, and the second one to any small remaining contribution from peaks 3 and 4 or from contaminants. The sum of the two Weibull curves is the glow curve signal result. GCA provides rapid review and correction of all glow curves, improving the quality of the results and reducing the time required for complete processing of official dose results

  13. Detection of irradiated foods by the thermoluminescence. Relationships between the temperature ranges of integrating TL glow curves and TL glow ratios

    International Nuclear Information System (INIS)

    Sekiguchi, Masayuki; Yamazaki, Masao; Goto, Michiko; Todoriki, Setsuko; Hagiwara, Shoji

    2007-01-01

    Our study demonstrated that the effects of the several temperature ranges for integrating TL glow intensity on the TL glow ratios by using spice-set purchased at a Turkish air port. The spice set had no labeling of irradiation feeds, but nine of 12 spices were judged as irradiated food in this study. Those temperature ranges were defined by evaluating the glow curves of irradiated TLD-100 chip (167-230degC), TLD-100 disc (177-238degC) and Dolomite element (145-258degC). Those are relatively stable and the difference of typical glow peak temperatures of TLD-100 disc in two institutes was less than 2%. On the other hand, those of TLD-100 tip was shift to higher temperature side at about 4degC because of declining of thermal conductance. The temperature ranges defined by TLD-100 were showed that discriminate more clearly between irradiated and nonirradiated spices compared with the full temperature range of TL measurement (70-400degC). With the exception of low glow intensity, background measurement for estimating net glow intensity was not necessary because TL glow ratio was hardly influenced whether the background measured or not. (author)

  14. Aurora-A overexpression and aneuploidy predict poor outcome in serous ovarian carcinoma.

    Science.gov (United States)

    Lassus, Heini; Staff, Synnöve; Leminen, Arto; Isola, Jorma; Butzow, Ralf

    2011-01-01

    Aurora-A is a potential oncogene and therapeutic target in ovarian carcinoma. It is involved in mitotic events and overexpression leads to centrosome amplification and chromosomal instability. The objective of this study was to evaluate the clinical significance of Aurora-A and DNA ploidy in serous ovarian carcinoma. Serous ovarian carcinomas were analysed for Aurora-A protein by immunohistochemistry (n=592), Aurora-A copy number by CISH (n=169), Aurora-A mRNA by real-time PCR (n=158) and DNA ploidy by flowcytometry (n=440). Overexpression of Aurora-A was found in 27% of the tumors, cytoplasmic overexpression in 11% and nuclear in 17%. The cytoplasmic and nuclear overexpression were nearly mutually exclusive. Both cytoplasmic and nuclear overexpression were associated with shorter survival, high grade, high proliferation index and aberrant p53. Interestingly, only cytoplasmic expression was associated with aneuploidy and expression of phosphorylated Aurora-A. DNA ploidy was associated with poor patient outcome as well as aggressive clinicopathological parameters. In multivariate analysis, Aurora-A overexpression appeared as an independent prognostic factor for disease-free survival, together with grade, stage and ploidy. Aurora-A protein expression is strongly linked with poor patient outcome and aggressive disease characteristics, which makes Aurora-A a promising biomarker and a potential therapeutic target in ovarian carcinoma. Cytoplasmic and nuclear Aurora-A protein may have different functions. DNA aneuploidy is a strong predictor of poor prognosis in serous ovarian carcinoma. Copyright © 2010 Elsevier Inc. All rights reserved.

  15. Use of glow discharge in measurement of diffusion profile

    International Nuclear Information System (INIS)

    Baudin, Guy

    1976-05-01

    The composition of a glow discharge plasma is a good image of the composition of the surface being erroded without fusion. The depth of metal eated away is a linear function of time in 10 to 60μ range, that is too say between 2 and 20 minutes after lightning of the lamp. So measuring the emission of the discharge is function of time gives the diffusion profile of elements either by measuring instantaneous signal or by integrating during short periods of time for weak concentration. Examples of application for diffusion of N 2 and C in steel will be given [fr

  16. The mechanism of nickel ferrite formation by glow discharge effect

    Science.gov (United States)

    Frolova, L. A.

    2018-04-01

    The influence of various factors on the formation of nickel ferrite by the glow discharge effect has been studied. The ferritization process in the system FeSO4-NiSO4-NaOH-H2O has been studied by the methods of potentiometric titration, measurement of electrical conductivity, residual concentrations and apparent sediment volume. It has been established that the process proceeds in a multistage fashion at pH 11-12 with the formation of polyhydroxo complexes, an intermediate compound and the ferrite formation by its oxidation with active radicals.

  17. Nitrogen Glow Discharge by a DC Virtual Cathode

    Science.gov (United States)

    Shager, Azza M.; Sroor, Amany T.; Tayeb, Hoda A. El; Gamal, Hoda A. El; Masoud, Mohamed M.

    2008-08-01

    A DC glow discharge operating with a virtual cathode is studied. The system consists of a solid disc cathode and mesh anode. The discharge occurs in nitrogen gas at the left-hand side of Paschen's curve. The plasma electron density in the axial direction has been found to be 0.2 · 108 cm-3 at 2 cm from the mesh. The electron temperature peak value has been found to be 3.5 eV at 6 cm from the mesh. The radial distribution of the plasma electron density and temperature are discussed. The variation of the plasma parameters are in good agreement with the experimental results.

  18. Uncertainty of relative sensitivity factors in glow discharge mass spectrometry

    Science.gov (United States)

    Meija, Juris; Methven, Brad; Sturgeon, Ralph E.

    2017-10-01

    The concept of the relative sensitivity factors required for the correction of the measured ion beam ratios in pin-cell glow discharge mass spectrometry is examined in detail. We propose a data-driven model for predicting the relative response factors, which relies on a non-linear least squares adjustment and analyte/matrix interchangeability phenomena. The model provides a self-consistent set of response factors for any analyte/matrix combination of any element that appears as either an analyte or matrix in at least one known response factor.

  19. Letter to the EditorTwo early observations of aurora at low latitudes

    Directory of Open Access Journals (Sweden)

    J. M. Vaquero

    2001-07-01

    Full Text Available It is the purpose of this paper to present evidence concerning the observation of aurorae in the years 880 AD and 942 AD recorded by Arabs from the Iberian Peninsula and the north of Africa.Key words. Meteorology and atmospheric dynamics (general or miscellaneous – Atmospheric composition and structure (airglow and aurora – Magnetospheric physics (auroral phenomena

  20. Polo-Like Kinase-1 Controls Aurora A Destruction by Activating APC/C-Cdh1

    NARCIS (Netherlands)

    van Leuken, Renske; Clijsters, Linda; van Zon, Wouter; Lim, Dan; Yao, XueBiao; Wolthuis, Rob M. F.; Yaffe, Michael B.; Medema, Rene H.; van Vugt, Marcel A. T. M.

    2009-01-01

    Polo-like kinase-1 (Plk1) is activated before mitosis by Aurora A and its cofactor Bora. In mitosis, Bora is degraded in a manner dependent on Plk1 kinase activity and the E3 ubiquitin ligase SCF-beta TrCP. Here, we show that Plk1 is also required for the timely destruction of its activator Aurora A

  1. Bora and Aurora-A continue to activate Plk1 in mitosis.

    Science.gov (United States)

    Bruinsma, Wytse; Macurek, Libor; Freire, Raimundo; Lindqvist, Arne; Medema, René H

    2014-02-15

    Polo-like kinase-1 (Plk1) is required for proper cell division. Activation of Plk1 requires phosphorylation on a conserved threonine in the T-loop of the kinase domain (T210). Plk1 is first phosphorylated on T210 in G2 phase by the kinase Aurora-A, in concert with its cofactor Bora. However, Bora was shown to be degraded prior to entry into mitosis, and it is currently unclear how Plk1 activity is sustained in mitosis. Here we show that the Bora-Aurora-A complex remains the major activator of Plk1 in mitosis. We show that a small amount of Aurora-A activity is sufficient to phosphorylate and activate Plk1 in mitosis. In addition, a fraction of Bora is retained in mitosis, which is essential for continued Aurora-A-dependent T210 phosphorylation of Plk1. We find that once Plk1 is activated, minimal amounts of the Bora-Aurora-A complex are sufficient to sustain Plk1 activity. Thus, the activation of Plk1 by Aurora-A may function as a bistable switch; highly sensitive to inhibition of Aurora-A in its initial activation, but refractory to fluctuations in Aurora-A activity once Plk1 is fully activated. This provides a cell with robust Plk1 activity once it has committed to mitosis.

  2. Numerical analysis of thermoluminescence glow curves; Analisis numerico de las cruvas de termoluminiscencia

    Energy Technology Data Exchange (ETDEWEB)

    Gomez Ros, J. M.; Delgado, A.

    1989-07-01

    This report presents a method for the numerical analysis of complex thermoluminescence glow curves resolving the individual glow peak components. The method employs first order kinetics analytical expressions and is based In a Marquart-Levenberg minimization procedure. A simplified version of this method for thermoluminescence dosimetry (TLD) is also described and specifically developed to operate whit Lithium Fluoride TLD-100. (Author). 36 refs.

  3. Glow experiment documentation of OMS/RCS pod and vertical stabilizer

    Science.gov (United States)

    1982-01-01

    Glow experiment documentation of one of the orbital maneuvering system (OMS) reaction control system (RCS) pods and a portion of the vertical stabilizer shows chemoluminescent effectresulting from atomic oxygen impacting the spacecraft and building to the point that the atomic oxygen atoms combine to form molecules of oxygen. The Image Intensifier on NIKON 35mm camera was used to record the glow.

  4. Glow experiment documentation of OMS/RCS pods and vertical stabilizer

    Science.gov (United States)

    1982-01-01

    Glow experiment documentation of orbital maneuvering system (OMS) reaction control system (RCS) pods and vertical stabilizer shows chemo-luminescent effect resulting from atomic oxygen impacting the spacecraft and building to the point that the atomic oxygen atoms combine to form molecules of oxygen. Image intensifier on NIKON 35mm camera was used to record glow on vertical tail and OMS pods.

  5. Aurora B is regulated by acetylation/deacetylation during mitosis in prostate cancer cells.

    Science.gov (United States)

    Fadri-Moskwik, Maria; Weiderhold, Kimberly N; Deeraksa, Arpaporn; Chuang, Carol; Pan, Jing; Lin, Sue-Hwa; Yu-Lee, Li-Yuan

    2012-10-01

    Protein acetylation has been implicated in playing an important role during mitotic progression. Aurora B kinase is known to play a critical role in mitosis. However, whether Aurora B is regulated by acetylation is not known. Using IP with an anti-acetyl lysine antibody, we identified Aurora B as an acetylated protein in PC3 prostate cancer cells. Knockdown of HDAC3 or inhibiting HDAC3 deacetylase activity led to a significant increase (Pmitosis. Together, these results indicate that Aurora B is more active in its deacetylated state and further suggest a new mechanism by which dynamic acetylation/deacetylation acts as a rheostat to fine-tune Aurora B activity during mitotic progression.

  6. Expression of Aurora-B and FOXM1 predict poor survival in patients with nasopharyngeal carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Pei-Yu; Luo, Dong-Hua; Mai, Hai-Qiang [State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou (China); Sun Yat-sen University Cancer Center, Department of Nasopharyngeal Carcinoma, Guangzhou (China); Li, Yan; Zeng, Ting-Ting; Li, Meng-Qing [State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou (China); Hou, Xue; Zhang, Li [State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou (China); Sun Yat-sen University Cancer Center, Department of Medical Oncology, Guangzhou (China)

    2015-08-15

    The purpose of this work was to investigate the relationship between Aurora-B, FOXM1, and clinical outcomes in patients with nasopharyngeal carcinoma (NPC) who were treated with a combination of induction chemotherapy and radiotherapy. The expression of Aurora-B and FOXM1 were investigated by immunohistochemistry using a tissue microarray (TMA) containing samples from 166 NPC patients who were treated with cisplatin (DDP) + fluorouracil (5-FU) induction chemotherapy and radiotherapy between 1999 and 2005. The relationship of Aurora-B, FOXM1, and survival of these NPC patients was analyzed. Informative TMA results were obtained in 91 tumor cases for Aurora-B and 93 tumor cases for FOXM1. The 8-year failure-free survival rate (FFS) for the Aurora-B-negative and Aurora-B-positive group was 65.6 and 37.3 %, respectively (p = 0.024), and the 8-year distant FFS (D-FFS) rate was 65.6 and 41.5 %, respectively (p = 0.047). The 8-year overall survival (OS) in the FOXM1-negative group was moderately higher than in the FOXM1-positive group (58.4 vs 39.1 %, p = 0.081). Cox regression analysis revealed that for FFS, Aurora-B expression was a significant prognostic factor (p = 0.025), while for D-FFS, Aurora-B expression was a marginally significant prognostic factor (p = 0.056). When FOXM1 expression was analyzed, the Cox regression analyses showed that FOXM1 expression was a marginally significant prognostic factor (p = 0.056) for OS. Correlation analysis showed that Aurora-B and FOXM1 expression had no significant correlation. Aurora-B and FOXM1 were both adverse prognostic markers for NPC patients treated with chemoradiotherapy. However, the two markers had no significant correlation. (orig.) [German] Ziel war die Untersuchung der Beziehung zwischen Aurora-B, FOXM1 und den klinischen Ergebnissen bei Patienten mit nasopharyngealem Karzinom (NPC), die mit einer Kombinationstherapie aus Induktionschemotherapie und Radiotherapie behandelt wurden. Die Expression von Aurora-B und

  7. The Aurora B kinase in chromosome biorientation and spindle checkpoint signalling

    Directory of Open Access Journals (Sweden)

    Veronica eKrenn

    2015-10-01

    Full Text Available Aurora B, a member of the Aurora family of serine/threonine protein kinases, is a key player in chromosome segregation. As part of a macromolecular complex known as the chromosome passenger complex, Aurora B concentrates early during mitosis in the proximity of centromeres and kinetochores, the sites of attachment of chromosomes to spindle microtubules. There, it contributes to a number of processes that impart fidelity to cell division, including kinetochore stabilization, kinetochore-microtubule attachment, and the regulation of a surveillance mechanism named the spindle assembly checkpoint. In the regulation of these processes, Aurora B is the fulcrum of a remarkably complex network of interactions that feed back on its localization and activation state. In this review we discuss the multiple roles of Aurora B during mitosis, focusing in particular on its role at centromeres and kinetochores. Many details of the network of interactions at these locations remain poorly understood, and we focus here on several crucial outstanding questions.

  8. Research on the Plasma Anemometer Based on AC Glow Discharge

    Directory of Open Access Journals (Sweden)

    Bing Yu

    2017-01-01

    Full Text Available A new plasma anemometer based on AC glow discharge is designed in this article. Firstly, theoretical analysis of plasma anemometer working principle is introduced to prove the feasibility of the experimental measurement method. Then the experiments are carried out to study the effects of different parameters on the static discharge characteristics of the plasma anemometer system, by which the system optimization methods are obtained. Finally, several groups of appropriate parameters are selected to build the plasma anemometer system based on resistance capacitance coupling negative feedback AC glow discharge, and different airflow speeds are applied to obtain the achievable velocity measurement range. The results show that there is a linear relationship between airflow velocity and discharge current in an allowable error range, which can be applied for airflow velocity measurement. Negative feedback coupling module, which is composed of the coupling resistance and the coupling capacitance, has good effects on improving the system stability. The measurement range of the airflow velocity is significantly increased when the electrode gap is 3 mm, coupling resistance is 470 Ω, and coupling capacitance is 220 pF.

  9. Synthesis of nanoparticles in an atmospheric pressure glow discharge

    International Nuclear Information System (INIS)

    Barankin, M.D.; Creyghton, Y.; Schmidt-Ott, A.

    2006-01-01

    Nanopowders are produced in a low temperature, non-equilibrium plasma jet (APPJ), which produces a glow discharge at atmospheric pressure, for the first time. Amorphous carbon and iron nanoparticles have been synthesized from Acetylene and Ferrocene/H 2 , respectively. High generation rates are achieved from the glow discharge at near-ambient temperature (40-80 deg. C), and rise with increasing plasma power and precursor concentration. Fairly narrow particle size distributions are measured with a differential mobility analyzer (DMA) and an aerosol electrometer (AEM), and are centered around 30-35 nm for carbon and 20-25 nm for iron. Particle characteristics analyzed by TEM and EDX reveal amorphous carbon and iron nanoparticles. The Fe particles are highly oxidized on exposure to air. Comparison of the mobility and micrograph diameters reveal that the particles are hardly agglomerated or unagglomerated. This is ascribed to the unipolar charge on particles in the plasma. The generated particle distributions are examined as a function of process parameters

  10. Exploration to generate atmospheric pressure glow discharge plasma in air

    Science.gov (United States)

    Wenzheng, LIU; Chuanlong, MA; Shuai, ZHAO; Xiaozhong, CHEN; Tahan, WANG; Luxiang, ZHAO; Zhiyi, LI; Jiangqi, NIU; Liying, ZHU; Maolin, CHAI

    2018-03-01

    Atmospheric pressure glow discharge (APGD) plasma in air has high application value. In this paper, the methods of generating APGD plasma in air are discussed, and the characteristics of dielectric barrier discharge (DBD) in non-uniform electric field are studied. It makes sure that APGD in air is formed by DBD in alternating current electric field with using the absorbing electron capacity of electret materials to provide initial electrons and to end the discharge progress. Through designing electric field to form two-dimensional space varying electric field and three-dimensional space varying electric field, the development of electron avalanches in air-gap is suppressed effectively and a large space of APGD plasma in air is generated. Further, through combining electrode structures, a large area of APGD plasma in air is generated. On the other hand, by using the method of increasing the density of initial electrons, millimeter-gap glow discharge in atmospheric pressure air is formed, and a maximum gap distance between electrodes is 8 mm. By using the APGD plasma surface treatment device composed of contact electrodes, the surface modification of high polymer materials such as aramid fiber and polyester are studied and good effect of modifications is obtained. The present paper provides references for the researchers of industrial applications of plasma.

  11. Electric probe data analysis for glow discharge diagnostics

    International Nuclear Information System (INIS)

    Cain, B.L.

    1987-01-01

    This report summarizes the development and application of digital computations for the analysis of data from an electric probe used for glow discharge diagnostics. The essential physics of the probe/discharge interaction is presented, along with formulations from modern electric probe theory. These results are then digitally implemented by a set of computer programs which both calculate discharge properties of electron temperature and density, and aid in the interpretation of these property estimates. The method of analysis, and the theories selected for implementation, are valid only for low pressure, collisionless sheath, and quiescent discharges where the single electric probe has a much smaller area than the discharge reference electrode. However, certain algorithms are included which, in some cases, can extend the analysis into intermediate pressure regimes. The digital programs' functional capabilities are demonstrated by the analysis of experimental probe data, collected using a laboratory glow discharge. Typical sources of error inherent in the electric probe method are discussed, along with an analysis of error induced by the computational methods of the programs. 27 refs., 49 figs., 20 tabs

  12. Basal aurora kinase B activity is sufficient for histone H3 phosphorylation in prophase

    Directory of Open Access Journals (Sweden)

    Ly-Thuy-Tram Le

    2013-02-01

    Histone H3 phosphorylation is the hallmark of mitosis deposited by aurora kinase B. Benzo[e]pyridoindoles are a family of potent, broad, ATP-competitive aurora kinase inhibitors. However, benzo[e]pyridoindole C4 only inhibits histone H3 phosphorylation in prophase but not in metaphase. Under the C4 treatment, the cells enter into mitosis with dephosphorylated histone H3, assemble chromosomes normally and progress to metaphase, and then to anaphase. C4 also induces lagging chromosome in anaphase but we demonstrated that these chromosome compaction defects are not related to the absence of H3 phosphorylation in prophase. As a result of C4 action, mitosis lasts longer and the cell cycle is slowed down. We reproduced the mitotic defects with reduced concentrations of potent pan aurora kinase as well as with a specific aurora B ATP-competitive inhibitor; we therefore propose that histone H3 phosphorylation and anaphase chromosome compaction involve the basal activity of aurora kinase B. Our data suggest that aurora kinase B is progressively activated at mitosis entry and at anaphase onset. The full activation of aurora kinase B by its partners, in prometaphase, induces a shift in the catalytic domain of aurora B that modifies its affinity for ATP. These waves of activation/deactivation of aurora B correspond to different conformations of the chromosomal complex revealed by FRAP. The presence of lagging chromosomes may have deleterious consequences on the daughter cells and, unfortunately, the situation may be encountered in patients receiving treatment with aurora kinase inhibitors.

  13. Inhibition of Survivin and Aurora B Kinase Sensitizes Mesothelioma Cells by Enhancing Mitotic Arrests

    International Nuclear Information System (INIS)

    Kim, Kwang Woon; Mutter, Robert W.; Willey, Christopher D.; Subhawong, Ty K.; Shinohara, Eric T.; Albert, Jeffrey M.; Ling Geng; Cao, Carolyn; Gi, Young Jin; Bo Lu

    2007-01-01

    Purpose: Survivin, a member of the inhibitor of apoptosis gene family, has also been shown to regulate mitosis. It binds Aurora B kinase and the inner centromere protein to form the chromosome passenger complex. Both Aurora B and survivin are overexpressed in many tumors. In this study, we examined whether irradiation affected survivin and Aurora B expression in mesothelioma cells, and how inhibition of these molecules affected radiosensitivity. Methods and Materials: ZM447439 and survivin antisense oligonucleotides were used to inhibit survivin and Aurora B kinase respectively. Western blot was performed to determine the expression of survivin, Aurora B, phosphorylated-histone H3 (Ser 10), and caspase cleavage. Multinucleated cells were counted using flow cytometry, and cell survival after treatment was determined using clonogenic assay. Results: At 3-Gy irradiation an increase was observed in levels of survivin and Aurora B as well as the kinase activity of Aurora B, with an increase in G2/M phase. The radiation-induced upregulation of these molecules was effectively attenuated by antisense oligonucleotides against survivin and a small-molecule inhibitor of Aurora B, ZM447439. Dual inhibition of survivin and Aurora B synergistically radiosensitized mesothelioma cells with a dose enhancement ratio of 2.55. This treatment resulted in increased formation of multinucleated cells after irradiation but did not increase levels of cleaved caspase 3. Conclusion: Inhibition of survivin and Aurora B induces mitotic cell arrest in mesothelioma cells after irradiation. These two proteins may be potential therapeutic targets for the enhancement of radiotherapy in malignant pleural mesothelioma

  14. Long duration gamma-ray glows observed from the tops of thunderstorms

    Science.gov (United States)

    Kelley, N.; Smith, D. M.; Dwyer, J. R.; Hazelton, B. J.; Grefenstette, B. W.; Lowell, A.; Splitt, M. E.; Lazarus, S. M.; Rassoul, H. K.

    2011-12-01

    The Airborne Detector for Energetic Lightning Emissions (ADELE) observed 12 γ-ray glows from thunderstorms near Montana and Florida during its Summer 2009 campaign. These glows have been observed from both the ground and air but this is the first evidence that they are a common, long duration occurrence at the tops of thunderclouds. Glows could be evidence that continuous relativistic runaway with feedback limits thunderstorm charging in a way that competes with lightning. We compare our observed glows to local lightning activity and find a slight but poor correlation, indicating that lightning and glows measure different aspects of cloud electrification. We have shown for all 11 of our observed glows in Florida that there is always an active cell nearby, but there were also many passes near active cells that had no observed glow. We will examine the meteorological differences between active lightning cells with and without glows. We have found the spectrum to be very hard for each glow, with a large fraction of the counts being above 5 MeV. Using a Monte Carlo simulation of relativistic runaway with positron feedback and a GEANT3 model of the atmosphere and instrument response from within a plane, we will distinguish between two different possibilities for a hard spectrum: an upward relativistic avalanche very deep in the atmosphere, so that most low energy photons have been removed via Compton scattering, and a downward relativistic avalanche between the upper positive and the screening layer, with the bremsstrahlung from the upward positron beam (a side-effect of feedback) producing the glow. If the latter model is correct, it demonstrates that positron feedback is indeed a common process in thunderclouds.

  15. Pulsating aurora from electron scattering by chorus waves

    Science.gov (United States)

    Kasahara, S.; Miyoshi, Y.; Yokota, S.; Mitani, T.; Kasahara, Y.; Matsuda, S.; Kumamoto, A.; Matsuoka, A.; Kazama, Y.; Frey, H. U.; Angelopoulos, V.; Kurita, S.; Keika, K.; Seki, K.; Shinohara, I.

    2018-02-01

    Auroral substorms, dynamic phenomena that occur in the upper atmosphere at night, are caused by global reconfiguration of the magnetosphere, which releases stored solar wind energy. These storms are characterized by auroral brightening from dusk to midnight, followed by violent motions of distinct auroral arcs that suddenly break up, and the subsequent emergence of diffuse, pulsating auroral patches at dawn. Pulsating aurorae, which are quasiperiodic, blinking patches of light tens to hundreds of kilometres across, appear at altitudes of about 100 kilometres in the high-latitude regions of both hemispheres, and multiple patches often cover the entire sky. This auroral pulsation, with periods of several to tens of seconds, is generated by the intermittent precipitation of energetic electrons (several to tens of kiloelectronvolts) arriving from the magnetosphere and colliding with the atoms and molecules of the upper atmosphere. A possible cause of this precipitation is the interaction between magnetospheric electrons and electromagnetic waves called whistler-mode chorus waves. However, no direct observational evidence of this interaction has been obtained so far. Here we report that energetic electrons are scattered by chorus waves, resulting in their precipitation. Our observations were made in March 2017 with a magnetospheric spacecraft equipped with a high-angular-resolution electron sensor and electromagnetic field instruments. The measured quasiperiodic precipitating electron flux was sufficiently intense to generate a pulsating aurora, which was indeed simultaneously observed by a ground auroral imager.

  16. Terrestrial aurora: astrophysical laboratory for anomalous abundances in stellar systems

    Directory of Open Access Journals (Sweden)

    I. Roth

    2014-02-01

    Full Text Available The unique magnetic structure of the terrestrial aurora as a conduit of information between the ionosphere and magnetosphere can be utilized as a laboratory for physical processes at similar magnetic configurations and applied to various evolutionary phases of the solar (stellar system. The most spectacular heliospheric abundance enhancement involves the 3He isotope and selective heavy elements in impulsive solar flares. In situ observations of electromagnetic waves on active aurora are extrapolated to flaring corona in an analysis of solar acceleration processes of 3He, the only element that may resonate strongly with the waves, as well as heavy ions with specific charge-to-mass ratios, which may resonate weaker via their higher gyroharmonics. These results are applied to two observed anomalous astrophysical abundances: (1 enhanced abundance of 3He and possibly 13C in the late stellar evolutionary stages of planetary nebulae; and (2 enhanced abundance of the observed fossil element 26Mg in meteorites as a decay product of radioactive 26Al isotope due to interaction with the flare-energized 3He in the early solar system.

  17. A comparison of optical and coherent HF radar backscatter observations of a post-midnight aurora

    Directory of Open Access Journals (Sweden)

    S. E. Milan

    Full Text Available A poleward-progressing 630 nm optical feature is observed between approximately 0100 UT and 0230 UT (0400 MLT to 0530 MLT by a meridian-scanning photometer (MSP located at Ny Ålesund, Svalbard. Simultaneous coherent HF radar measurements indicate a region of poleward-expanding backscatter with rapid sunward plasma flow velocity along the MSP meridian. Spatial maps of the backscatter indicate a stationary backscatter feature aligned obliquely with respect to the MSP meridian, which produces an impression of poleward-expansion as the MSP progresses to later MLT. Two interpretations of the observations are possible, depending on whether the arc system is considered to move (time-dependent or to be stationary in time and apparent motion is produced as the MSP meridian rotates underneath it (time-independent. The first interpretation is as a poleward motion of an east-west aligned auroral arc. In this case the appearance of the region of backscatter is not associated with the optical feature, though the velocities within it are enhanced when the two are co-located. The second interpretation is as a polar arc or theta aurora, common features of the polar cap under the prevailing IMF northwards conditions. In this case the backscatter appears as an approximately 150 km wide region adjacent to the optical arc. In both interpretations the luminosity of the optical feature appears related to the magnitude of the plasma flow velocity. The optical features presented here do not generate appreciable HF coherent backscatter, and are only identifiable in the backscatter data as a modification of the flow by the arc electrodynamics.

  18. Estimation of radiation doses in TGFs and gamma ray glows

    Science.gov (United States)

    Celestin, S. J.; Pincon, J. L.; Trompier, F.

    2017-12-01

    Terrestrial gamma-ray flashes (TGFs) are bursts of high-energy photons originating from the Earth's atmosphere in association with thunderstorm activity [e.g., Briggs et al., JGR, 118, 3805, 2013]. TGFs are associated with initial propagation stages of intracloud lightning, which represent the most frequent type of lightning discharges [e.g., Cummer et al., GRL, 42, 7792, 2015, and references therein]. TGFs are known to be produced inside common thunderclouds [e.g., Splitt et al., JGR, 115, A00E38, 2010; Chronis et al., B. Am. Meteorol. Soc., 97, 639, 2016] typically at altitudes ranging from 10 to 14 km [e.g., Cummer et al., GRL, 41, 8586, 2014]. The global TGF occurrence rate is estimated to be 400,000 per year concerning TGFs detectable by Fermi-GBM (Gamma ray Burst Monitor) [Briggs et al., 2013], but detailed analysis of satellite measurements [Østgaard et al., JGR, 117, A03327, 2012] and theoretical studies [Celestin et al., JGR, 120, 10712, 2015] suggest that it cannot be excluded that TGFs represent a part of a regular process taking place during the propagation of lightning discharges. In addition to TGFs, another type of high-energy emissions has been observed inside thunderstorms from balloons [e.g., Eack et al., 101, 29637, 1996] and airplanes [e.g., McCarthy and Parks, 12, 393, 1985; Kelley et al., Nat. Commun., 6, 7845, 2015]. Referred to as gamma ray glows, these events correspond to significant elevations of the background radiation over long time scales that can be abruptly terminated with the occurrence of a lightning discharge. Kelley et al. [2015] estimate that a proportion larger than 8% of electrified storms produce glows. Dwyer et al. [JGR, 115, D09206, 2010] have estimated that if an aircraft were to find itself in the source electron beam giving rise to a TGF, passengers and crews might receive effective radiation doses above the regulatory limit depending on the beam diameter and Tavani et al. [Nat. Hazards Earth Syst. Sci., 13, 1127, 2013

  19. Survivin inhibits anti-growth effect of p53 activated by aurora B

    International Nuclear Information System (INIS)

    Jung, Ji-Eun; Kim, Tae-Kyung; Lee, Joong-Seob; Oh, Se-Yeong; Kwak, Sungwook; Jin, Xun; Sohn, Jin-Young; Song, Min-Keun; Sohn, Young-Woo; Lee, Soo-Yeon; Pian, Xumin; Lee, Jang-Bo; Chung, Yong Gu; Choi, Young Ki; You, Seungkwon; Kim, Hyunggee

    2005-01-01

    Genomic instability and apoptosis evasion are hallmarks of cancer, but the molecular mechanisms governing these processes remain elusive. Here, we found that survivin, a member of the apoptosis-inhibiting gene family, and aurora B kinase, a chromosomal passenger protein, were co-overexpressed in the various glioblastoma cell lines and tumors. Notably, exogenous introduction of the aurora B in human BJ cells was shown to decrease cell growth and increase the senescence-associated β-galactosidase activity by activation of p53 tumor suppressor. However, aurora B overexpression failed to inhibit cell proliferation in BJ and U87MG cells transduced with dominant-negative p53 as well as in p53 -/- mouse astrocytes. Aurora B was shown to increase centrosome amplification in the p53 -/- astrocytes. Survivin was shown to induce anchorage-independent growth and inhibit anti-proliferation and drug-sensitive apoptosis caused by aurora B. Overexpression of both survivin and aurora B further accelerated the proliferation of BJ cells. Taken together, the present study indicates that survivin should accelerate tumorigenesis by inhibiting the anti-proliferative effect of p53 tumor suppressor that is activated by aurora B in normal and glioblastoma cells containing intact p53

  20. Modeling of Pulsed Direct-Current Glow Discharge

    International Nuclear Information System (INIS)

    Du Mu; Zheng Yaru; Fan Yujia; Zhang Nan; Liu Chengsen; Wang Dezhen

    2010-01-01

    A self-consistent model was adopted to study the time evolution of low-voltage pulsed DC glow discharge. The distributions of electric field, ion density and electron density in nitrogen were investigated in our simulation, and the temporal shape of the discharge current was also obtained. Our results show that the dynamic behaviors of the discharge depends strongly on the applied pulse voltage, and the use of higher pulse voltages results in a significantly increase of discharge current and a decrease of discharge delay time. The current-voltage characteristic calculated by adjusting secondary electron emission coefficient for different applied pulse voltage under the gas pressure of 1 Torr is found in a reasonable agreement with the experimental results.

  1. Gas Temperature Measurement in a Glow Discharge Plasma

    Science.gov (United States)

    Sloneker, Kenneth; Podder, Nirmol; McCurdy, William E.; Shi, Shi

    2009-10-01

    In this study a relatively inexpensive quartz protected thermocouple is used to measure the gas temperature in the positive column of a glow discharge plasma. For simplicity a K-type thermocouple is used to interpret the gas temperature from the sensor voltage at pressures from 0.5 Torr to 15 Torr and discharge currents from 5 mA to 120 mA. Gas temperature is investigated as a function of the gas pressure at fixed discharge currents and as a function of discharge current at fixed gas pressures in three different gas species (Ar, N2, and He). An infinite cylinder model is used to compute the average gas temperature of the discharge from joule heating and gas thermal conductivity. The model and measurement data agree within 1% to 10% depending on plasma parameters. Data for all three gases have a similar quasi-linear increasing error as compared to the model.

  2. In-Flight Observation of Gamma Ray Glows by ILDAS

    Science.gov (United States)

    Kochkin, Pavlo; van Deursen, A. P. J.; Marisaldi, M.; Ursi, A.; de Boer, A. I.; Bardet, M.; Allasia, C.; Boissin, J.-F.; Flourens, F.; Østgaard, N.

    2017-12-01

    An Airbus A340 aircraft flew over Northern Australia with the In-Flight Lightning Damage Assessment System (ILDAS) installed onboard. A long-duration gamma ray emission was detected. The most intense emission was observed at 12 km altitude and lasted for 20 s. Its intensity was 20 times the background counts, and it was abruptly terminated by a distant lightning flash. In this work we reconstruct the aircraft path and event timeline. The glow-terminating flash triggered a discharge from the aircraft wing that was recorded by a video camera operating onboard. Another count rate increase was observed 6 min later and lasted for 30 s. The lightning activity as reported by ground networks in this region was analyzed. The measured spectra characteristics of the emission were estimated.

  3. Sputtering of the 1020 AISI steel in abnormal glow discharge

    Science.gov (United States)

    García Zúñiga, J. A.; Sarmiento Santos, A.; Álvarez Luna, B.

    2017-12-01

    In all material treated in Sbnormal Glow Discharge (AGD) the phenomenon of sputtering occurs. In this work we study the sputtering suffered at different temperatures by AISI 1020 steel subjected to a DC discharge in two types of atmospheres. The steel samples were previously sanded until obtaining mirror brightness and subjected to the AGD plasma in the gaseous atmospheres of H2 and Ar. The temperature for each sputtering process was set in the range of 420°C to 600°C. In these samples the mass variation was measured and the yield sputtering processes was determined. Next, the simulation of the sputtering process was performed in the SRIM/TRIM 2008 software, by adjusting sputtering yield computational computations to those experimentally measured, in order to determine the energy with which the responsible ions of the sputtering collide with studied target.

  4. Tantalum etching in fluorocarbon/oxygen rf glow discharges

    International Nuclear Information System (INIS)

    Martz, J.C.; Hess, D.W.; Anderson, W.E.

    1990-01-01

    Etch rates of tantalum in tetrafluoromethane-oxygen and hexafluoroethane-oxygen rf glow discharges were measured in situ as functions of pressure, reactor residence time, temperature, and applied plasma power. A dramatic increase in the etch rate was observed as the pressure increased. In addition, two distinct temperature regimes occurred in Arrhenius plots. Such data suggest strong effects due to heat of reaction in the Ta/CF 4 -O 2 etch system. The observed etch-rate pressure dependence can be explained by assuming first-order kinetics for the reaction of fluorine atoms with tantalum. Evidence for etch-rate quenching at high pressures due to an increase in the deposition of an inhibiting fluorocarbon surface layer is presented

  5. Simulations of the neutral structure within the dusk side aurora

    Directory of Open Access Journals (Sweden)

    H. F. Parish

    2006-10-01

    Full Text Available Observations of neutral winds from rocket release experiments within the premidnight and postmidnight substorm recovery phase aurora, show very large E-region neutral winds of several hundred m/s, where winds measured on the dusk side are even larger than those on the dawn side. These large winds are also associated with strong shears, and there is evidence that some of the regions below these shears may be unstable. The mechanisms which generate this strong vertical structure are not well understood. It is also not known whether the acceleration conditions in the pre and post midnight sectors of the aurora may produce significantly different neutral responses on the dawn and dusk sides. Simulations have been performed using a three-dimensional high resolution limited area thermosphere model to try to understand the neutral structure within the dawn and dusk side aurora. When simulations are performed using auroral forcing alone, for equivalent conditions within the dawn and dusk sectors, differences are found in the simulated response on each side. When measured values of auroral forcing parameters, and background winds and tides consistent with recent observations, are used as model inputs, some of the main features of the zonal and meridional wind observations are reproduced in the simulations, but the magnitude of the peak zonal wind around 140 km tends to be too small and the maximum meridional wind around 130 km is overestimated. The winds above 120 km altitude are found to be sensitive to changes in electric fields and ion densities, as was the case for the dawn side, but the effects of background winds and tides on the magnitudes of the winds above 120 km are found to be relatively small on the dusk side. The structure below 120 km appears to be related mainly to background winds and tides rather than auroral forcing, as was found in earlier studies on the dawn side, although the peak magnitudes of simulated wind variations in the 100 to

  6. Arsenic treatment increase Aurora-A overexpression through E2F1 activation in bladder cells.

    Science.gov (United States)

    Kao, Yu-Ting; Wu, Chin-Han; Wu, Shan-Ying; Lan, Sheng-Hui; Liu, Hsiao-Sheng; Tseng, Ya-Shih

    2017-04-18

    Arsenic is a widely distributed metalloid compound that has biphasic effects on cultured cells. In large doses, arsenic can be toxic enough to trigger cell death. In smaller amounts, non-toxic doses may promote cell proliferation and induces carcinogenesis. Aberration of chromosome is frequently detected in epithelial cells and lymphocytes of individuals from arsenic contaminated areas. Overexpression of Aurora-A, a mitotic kinase, results in chromosomal instability and cell transformation. We have reported that low concentration (≦1 μM) of arsenic treatment increases Aurora-A expression in immortalized bladder urothelial E7 cells. However, how arsenic induces carcinogenesis through Aurora-A activation remaining unclear. Bromodeoxyuridine (BrdU) staining, MTT assay, and flow cytometry assay were conducted to determine cell proliferation. Messenger RNA and protein expression levels of Aurora-A were detected by reverse transcriptional-PCR and Western blotting, respectively. Centrosome of cells was observed by immunofluorescent staining. The transcription factor of Aurora-A was investigated by promoter activity, chromosome immunoprecipitation (ChIP), and small interfering RNA (shRNA) assays. Mouse model was utilized to confirm the relationship between arsenic and Aurora-A. We reveal that low dosage of arsenic treatment increased cell proliferation is associated with accumulated cell population at S phase. We also detected increased Aurora-A expression at mRNA and protein levels in immortalized bladder urothelial E7 cells exposed to low doses of arsenic. Arsenic-treated cells displayed increased multiple centrosome which is resulted from overexpressed Aurora-A. Furthermore, the transcription factor, E2F1, is responsible for Aurora-A overexpression after arsenic treatment. We further disclosed that Aurora-A expression and cell proliferation were increased in bladder and uterus tissues of the BALB/c mice after long-term arsenic (1 mg/L) exposure for 2 months. We

  7. Note: Rapid reduction of graphene oxide paper by glow discharge plasma

    Energy Technology Data Exchange (ETDEWEB)

    Bo, Zheng; Qian, Jiajing; Duan, Liangping; Qiu, Kunzan, E-mail: qiukz@zju.edu.cn; Yan, Jianhua; Cen, Kefa [State Key Laboratory of Clean Energy Utilization, College of Energy Engineering, Zhejiang University, Hangzhou, Zhejiang 310027 (China); Han, Zhao Jun [CSIRO Manufacturing Flagship, P.O. Box 218, Bradfield Road, Lindfield, New South Wales 2070 (Australia); Ostrikov, Kostya [CSIRO Manufacturing Flagship, P.O. Box 218, Bradfield Road, Lindfield, New South Wales 2070 (Australia); Institute for Future Environments and School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, Queensland 4000 (Australia)

    2015-05-15

    This note reports on a novel method for the rapid reduction of graphene oxide (GO) paper using a glow discharge plasma reactor. Glow discharge is produced and sustained between two parallel-plate graphite electrodes at a pressure of 240 mTorr. By exposing GO paper at the junction of negative-glow and Faraday-dark area for 4 min, the oxygen-containing groups can be effectively removed (C/O ratio increases from 2.6 to 7.9), while the material integrality and flexibility are kept well. Electrochemical measurements demonstrate that the as-obtained reduced GO paper can be potentially used for supercapacitor application.

  8. Determination of the plasma impedance of a glow discharge in carbon dioxide

    Science.gov (United States)

    Kiselev, A. S.; Smirnov, E. A.

    2017-07-01

    In this work an expression for the dynamic resistance of a glow discharge flowing in long tubes is obtained and analyzed. The expression describes the physical processes occurring in the positive column of a glow discharge. The frequency dependences of the active and reactive components as well as the dynamic resistance module for the discharge conditions corresponding to CO2-lasers have been calculated. Based on the simulation results developed a computer program in the C# programming language for modeling the dynamic resistance discharge of glow discharge lasers.

  9. Accounting protesting and warm glow bidding in Contingent Valuation surveys considering the management of environmental goods

    DEFF Research Database (Denmark)

    Grammatikopoulou, Ioanna; Olsen, Søren Bøye

    2013-01-01

    Based on a Contingent Valuation survey aiming to reveal the willingness to pay (WTP) for conservation of a wetland area in Greece, we show how protest and warm glow motives can be taken into account when modeling WTP. In a sample of more than 300 respondents, we find that 54% of the positive bids...... are rooted to some extent in warm glow reasoning while 29% of the zero bids can be classified as expressions of protest rather than preferences. In previous studies, warm glow bidders are only rarely identified while protesters are typically identified and excluded from further analysis. We test...

  10. The charge spectrum of positive ions in a hydrogen aurora

    Science.gov (United States)

    Lynch, J.; Pulliam, D.; Leach, R.; Scherb, F.

    1976-01-01

    An auroral ion charge spectrometer was flown into a hydrogen aurora on a Javelin sounding rocket launched from Churchill, Manitoba. The instrument contained an electrostatic analyzer which selected particles with incident energy per unit charge up to 20 keV/charge and an 80-kV power supply which accelerated these ions onto an array of solid state detectors. Ions tentatively identified as H(+), He(+2), and O(+) were detected from 225 to 820 km in altitude. The experiment did not discriminate between H(+) and He(+), or between O(+), N(+), and C(+). Upper limits of highly charged heavy ion abundances have been set at 20% of the He(+2) and 0.15% of the H(+). It is concluded that both terrestrial and solar wind sources play significant roles in auroral ion precipitation.

  11. Beam propagation considerations in the Aurora laser system

    International Nuclear Information System (INIS)

    Rosoche, L.A.; Mc Leod, J.; Hanlon, J.A.

    1987-01-01

    Aurora is a high-power KrF laser system now being constructed for inertial confinement fusion (ICF) studies. It will use optical angular multiplexing and serial amplification by electron-beam-driven KrF amplifiers to deliver a stacked, multikilojoule 5-ns-duration laser pulse to ICF targets. The requirements of angular multiplexing KrF lasers at the multikilojoule level dictate path lengths on the order of 1 km. The inherent complicated path crossings produced by angular multiplexing and pulse stacking do not allow isolation of individual beam lines, so the optical quality of the long beam paths must be controlled. Propagation of the 248-nm light beams over long paths in air is affected by scattering, absorption thermal gradients and turbulence, beam alignment, and control and optical component figure errors

  12. Field-aligned electron flux oscillations that produce flickering aurora

    International Nuclear Information System (INIS)

    McFadden, J.P.; Carlson, C.W.; Boehm, M.H.; Hallinan, T.J.

    1987-01-01

    Measurements of energetic electrons that produce flickering aurora were made by a pair of sounding rockets launched during a slowly evolving auroral breakup. Both payloads passed through a broad inverted-V structure. A component of the electron distribution function was closely aligned with the magnetic field over a broad energy range that extended form low energies up to the inverted-V differential energy flux peak. High time resolution measurements of the field-aligned component showed the presence of order to magnitude coherent flux oscillations. Source altitudes between 4,000 and 8,000 km were derived from velocity dispersion of the flux oscillations. A ground-based TV camera recorded visual flickering in the vicinity of the payloads' auroral footprints during periods when flux oscillations were present. Measurements are compared with previous observations of electron flux oscillations, and possible sources for the field-aligned component are discussed

  13. Centromeric Transcription Regulates Aurora-B Localization and Activation

    Directory of Open Access Journals (Sweden)

    Michael D. Blower

    2016-05-01

    Full Text Available Centromeric transcription is widely conserved; however, it is not clear what role centromere transcription plays during mitosis. Here, I find that centromeres are transcribed in Xenopus egg extracts into a long noncoding RNA (lncRNA; cen-RNA that localizes to mitotic centromeres, chromatin, and spindles. cen-RNAs bind to the chromosomal passenger complex (CPC in vitro and in vivo. Blocking transcription or antisense inhibition of cen-RNA leads to a reduction of CPC localization to the inner centromere and misregulation of CPC component Aurora-B activation independently of known centromere recruitment pathways. Additionally, transcription is required for normal bipolar attachment of kinetochores to the mitotic spindle, consistent with a role for cen-RNA in CPC regulation. This work demonstrates that cen-RNAs promote normal kinetochore function through regulation of the localization and activation of the CPC and confirm that lncRNAs are components of the centromere.

  14. Exploring the Secrets of the Aurora Second Edition

    CERN Document Server

    Akasofu, Syun-Ichi

    2007-01-01

    This new edition of Exploring the Secrets of the Aurora is based on the author's own experiences as a scientist. It describes the history of progress made in auroral science and magnetospheric physics by providing examples of ideas, controversies, struggles, acceptance, and success. Although no general methodologies are mentioned, the hope is that the reader will learn about the history of progress in auroral science and examples of dealing with the many controversies. This book aims to help young scientific researchers learn how to persevere during periods of controversy and struggles for acceptance. In this second edition, by utilizing multiple examples, Akasofu is successful in demonstrating the importance and usefulness of Synthesis. "Probably the book's most valuable contribution to the history of space physics is precisely the narration of the discovery of substorms.---The book has special features.---Akasofu's coverage of the history of pre-space age solar-terrestrial relations is the most comprehensiv...

  15. Realidad, mito y deseo. La mirada grecolatina de Aurora Luque

    Directory of Open Access Journals (Sweden)

    Virtanen, Ricardo

    2011-08-01

    Full Text Available Aurora Luque’s poetry is one of the most representative of contemporary poetry, located within a Greek culturalism, where myth and reality blend into everyday life. Luque’s poetry is characterized by irony, nonchalance, frivolity and dedramatization. The article presents a series of poems where one can find a demystification of the classical element. A poetry stressed by some topoi such as carpe diem or Catullus’ odio et amo, which have been always represented from a light-hearted glance ruled by the spirit of Eros. The article also emphasizes the play on intertextuality –following Catullus– as well as the epicurean inclination/spirit/passion of the autor.

    La poesía de Aurora Luque representa una de las poéticas más representativas de nuestra contemporaneidad, ubicada dentro de un culturalismo grecista, donde mito y realidad se conjugan dentro de la cotidianidad. La poesía de Luque se caracteriza por su ironía, desenfado, frivolidad y desdramatización. El artículo presenta una serie de poemas donde se produce una desmitificación del elemento clásico. Una poesía marcada por algunos topoi como el carpe diem o el odio et amo catuliano, siempre representados desde una mirada desenfada y dominada por el espíritu del Eros. El artículo destaca además el juego de intertextualidad –en seguimiento de Catulo– así como la vocación epicúrea de la autora.

  16. 76 FR 65216 - Beacon Medical Services, LLC, Aurora, CO; Notice of Negative Determination Regarding Application...

    Science.gov (United States)

    2011-10-20

    ... coders'' at Beacon Medical Services, LLC, Aurora, Colorado, states that ``our jobs were outsourced to... shift in production by such workers' firm or subdivision to a foreign country of articles like or...

  17. E region neutral winds in the postmidnight diffuse aurora during the atmospheric response in aurora 1 rocket campaign

    International Nuclear Information System (INIS)

    Brinkman, D.G.; Walterscheid, R.L.; Lyons, L.R.

    1995-01-01

    Measured E region neutral winds from the Atmospheric Response in Aurora (ARIA 1) rocket campaign are compared with winds predicted by a high-resolution nonhydrostatic dynamical thermosphere model. The ARIA 1 rockets were launched into the postmidnight diffuse aurora during the recovery phase of a substorm. Simulations have shown that electrodynamical coupling between the auroral ionosphere and the thermosphere was expected to be strong during active diffuse auroral conditions. This is the first time that simulations using the time history of detailed specifications of the magnitude and latitudinal variation of the auroral forcing based on measurements have been compared to simultaneous wind measurements. Model inputs included electron densities derived from ground-based airglow measurements, precipitating electron fluxes measured by the rocket, electron densities measured on the rocket, electric fields derived from magnetometer and satellite ion drift measurements, and large-scale background winds from a thermospheric general circulation model. Our model predicted a strong jet of eastward winds at E region heights. A comparison between model predicted and observed winds showed modest agreement. Above 135 km the model predicted zonal winds with the correct sense, the correct profile shape, and the correct altitude of the peak wind. However, it overpredicted the magnitude of the eastward winds by more than a factor or 2. For the meridional winds the model predicted the general sense of the winds but was unable to predict the structure or strength of the winds seen in the observations. Uncertainties in the magnitude and latitudinal structure of the electric field and in the magnitude of the background winds are the most likely sources of error contributing to the differences between model and observed winds. Between 110 and 135 km the agreement between the model and observations was poor because of a large unmodeled jetlike feature in the observed winds

  18. Microhollow Glow Discharge Instrument for In Situ Lunar Surface Measurements, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Makel Engineering, Inc. (MEI) and Penn State University (PSU) propose to develop a highly sensitive spectrometer based on glow discharge plasma emission for the...

  19. The influence of a transverse magnetic field on a subnormal glow ...

    Indian Academy of Sciences (India)

    . D C JANA and S S PRADHAN. Department of Physics and Technophysics, Vidyasagar University, Midnapur 721 102, India. MS received 23 February 2000; revised 11 September 2000. Abstract. In subnormal glow discharge under d.c. ...

  20. A computerized glow curve analysis (GCA) method for WinREMS thermoluminescent dosimeter data using MATLAB

    International Nuclear Information System (INIS)

    Harvey, John A.; Rodrigues, Miesher L.; Kearfott, Kimberlee J.

    2011-01-01

    A computerized glow curve analysis (GCA) program for handling of thermoluminescence data originating from WinREMS is presented. The MATLAB program fits the glow peaks using the first-order kinetics model. Tested materials are LiF:Mg,Ti, CaF 2 :Dy, CaF 2 :Tm, CaF 2 :Mn, LiF:Mg,Cu,P, and CaSO 4 :Dy, with most having an average figure of merit (FOM) of 1.3% or less, with CaSO 4 :Dy 2.2% or less. Output is a list of fit parameters, peak areas, and graphs for each fit, evaluating each glow curve in 1.5 s or less. - Highlights: → Robust algorithm for performing thermoluminescent dosimeter glow curve analysis. → Written in MATLAB so readily implemented on variety of computers. → Usage of figure of merit demonstrated for six different materials.

  1. Magnetospheric magnetic field modelling for the 2011 and 2012 HST Saturn aurora campaigns – implications for auroral source regions

    Directory of Open Access Journals (Sweden)

    E. S. Belenkaya

    2014-06-01

    Full Text Available A unique set of images of Saturn's northern polar UV aurora was obtained by the Hubble Space Telescope in 2011 and 2012 at times when the Cassini spacecraft was located in the solar wind just upstream of Saturn's bow shock. This rare situation provides an opportunity to use the Kronian paraboloid magnetic field model to examine source locations of the bright auroral features by mapping them along field lines into the magnetosphere, taking account of the interplanetary magnetic field (IMF measured near simultaneously by Cassini. It is found that the persistent dawn arc maps to closed field lines in the dawn to noon sector, with an equatorward edge generally located in the inner part of the ring current, typically at ~ 7 Saturn radii (RS near dawn, and a poleward edge that maps variously between the centre of the ring current and beyond its outer edge at ~ 15 RS, depending on the latitudinal width of the arc. This location, together with a lack of response in properties to the concurrent IMF, suggests a principal connection with ring-current and nightside processes. The higher-latitude patchy auroras observed intermittently near to noon and at later local times extending towards dusk are instead found to straddle the model open–closed field boundary, thus mapping along field lines to the dayside outer magnetosphere and magnetopause. These emissions, which occur preferentially for northward IMF directions, are thus likely associated with reconnection and open-flux production at the magnetopause. One image for southward IMF also exhibits a prominent patch of very high latitude emissions extending poleward of patchy dawn arc emissions in the pre-noon sector. This is found to lie centrally within the region of open model field lines, suggesting an origin in the current system associated with lobe reconnection, similar to that observed in the terrestrial magnetosphere for northward IMF.

  2. The evening diffuse radio aurora, field-aligned currents and particle precipitation

    International Nuclear Information System (INIS)

    Unwin, R.S.

    1980-01-01

    The relationship of the afternoon/evening diffuse radio aurora, proton and electron precipitation and field-aligned currents is studied with data from the auroral radar at Slope Point, New Zealand, and the ISIS 2 satellite. It is shown that there is a very close association between the radio aurora and (primarily downward) field-aligned currents, which confirms and extends previous work, but that there is no clear relation with either proton or electron precipitation. (author)

  3. Glow curves and the emission of flux-grown BaFCl:Na crystals

    International Nuclear Information System (INIS)

    Somaiah, K.; Hari Babu, V.

    1984-01-01

    The thermoluminescence glow curves and the emission spectra of flux-grown BaFCl:Na crystals were recorded. An additional TL peak at 320 K, an optical absorption band at 570nm and an emission peak at 490 nm have been seen in X/γ-irradiated crystals. Bleaching, room-temperature annealing and high-temperature emission results led us to conclude that the sodium impurity is responsible for the additional glow peak optical absorption band and emission peak. (author)

  4. A Study of Electron Decay in Nitrogen Time After-glow

    International Nuclear Information System (INIS)

    Veis, P.; Coitout, H.; Magne, L.; Cernogora, G.

    1999-01-01

    This paper deals with electron density measurements in nitrogen time after-glow using hyper frequency resonant cavity. The studied pressures are from the range 9-530 Pa and discharge currents from 20 mA up to 500 mA. Electrons decreases up to the time of 1,4 ms in after-glow depending on pressure, pulse current and pulse duration (Authors)

  5. Study on out-gassing by baking and glow discharge during wall conditioning of vacuum chamber

    International Nuclear Information System (INIS)

    Wang Zhiwen; Wei Weixing; Zhao Yuanqing; He Yanhe; Liao Yikui

    2007-01-01

    The model of out-gassing by baking and glow discharge cleaning (GDC) is set up. The properties of them are studied. Out-gassing by baking is from bulk and it obeys the diffusion equation. Out-gassing of glow discharge cleaning is mainly on surface, it is inducement out-gassing by sputtering. Thus the properties of out-gassing for baking and GDC on the HL-1M tokamak are analyzed. Some empirical formulas are given. (authors)

  6. A SUMOylation Motif in Aurora-A: Implications in Spindle Dynamics and Oncogenesis

    Directory of Open Access Journals (Sweden)

    Ignacio ePérez de Castro

    2011-12-01

    Full Text Available Aurora-A is a serine/threonine kinase that plays critical roles in centrosome maturation, spindle dynamics and chromosome orientation and is frequently found overexpressed in human cancers. In this work, we show that Aurora-A interacts with the SUMO conjugating enzyme UBC9 and co-localizes with SUMO-1 in mitotic cells. Aurora-A can be SUMOylated in vitro and mutation in the highly conserved SUMOylation residue lysine 249 results in the induction of mitotic defects characterized by defective and multipolar spindles. The Aurora-AK249R mutant has normal kinase activity but it displays altered dynamics at the mitotic spindle. In addition, ectopic expression of the Aurora-AK249R mutant results in a significant increase in the susceptibility to malignant transformation induced by the Ras oncogene and an increased protection against apoptosis in tumor cells treated with mitotic poisons. These data suggest that modification by SUMO residues may control Aurora-A function at the spindle and suggest that deficient SUMOylation of this kinase may have relevant implications in tumor development or cancer therapy.

  7. The Dayside Aurora Brightening Associated with Magnetosheath High-Speed Jets and Their Related Magnetospheric Signatures

    Science.gov (United States)

    Wang, B.; Nishimura, Y.; Hietala, H.; Lyons, L. R.; Angelopoulos, V.; Ebihara, Y.

    2017-12-01

    Magnetosheath high speed jets (HSJs) are dayside transient disturbances with high speed velocity and large dynamic pressure. They are observed to be associated with significant magnetopause perturbations, ultra-low frequency (ULF) waves in the dayside magnetosphere, and localized flow enhancements in the ionosphere. However, whether HSJs also affect dayside aurora is still an open question, and if so, aurora properties can be used to deduce 2-d structure and evolution of HSJ effects in the magnetosphere. In this study, we use 11 HSJ events identified by the THEMIS satellites located within ±1 MLT of the center FOV of the South Pole station all sky imager (ASI). In 8 of those, the HSJs are observed to have a nearly one-to-one relationship with each localized discrete/diffuse auroral brightening. The azimuthal size of HSJ-related diffuse aurora signatures is 4 Re in the magnetosphere, which is slightly larger but of the order of the cross-sectional diameter of HSJs ( 1 Re). Besides, most of those aurora signatures have azimuthally motion ( 121 km/s), which shows consistency with magnetosheath background flows. This study for the first time showed the connection between magnetosheath HSJs and localized diffuse auroras. Diffuse aurora brightenings are also correlated with ULF waves in the dayside magnetosphere and ionosphere.

  8. Aurora Kinase A Promotes AR Degradation via the E3 Ligase CHIP.

    Science.gov (United States)

    Sarkar, Sukumar; Brautigan, David L; Larner, James M

    2017-08-01

    Reducing the levels of the androgen receptor (AR) is one of the most viable approaches to combat castration-resistant prostate cancer. Previously, we observed that proteasomal-dependent degradation of AR in response to 2-methoxyestradiol (2-ME) depends primarily on the E3 ligase C-terminus of HSP70-interacting protein (STUB1/CHIP). Here, 2-ME stimulation activates CHIP by phosphorylation via Aurora kinase A (AURKA). Aurora A kinase inhibitors and RNAi knockdown of Aurora A transcript selectively blocked CHIP phosphorylation and AR degradation. Aurora A kinase is activated by 2-ME in the S-phase as well as during mitosis, and phosphorylates CHIP at S273. Prostate cancer cells expressing an S273A mutant of CHIP have attenuated AR degradation upon 2-ME treatment compared with cells expressing wild-type CHIP, supporting the idea that CHIP phosphorylation by Aurora A activates its E3 ligase activity for the AR. These results reveal a novel 2-ME→Aurora A→CHIP→AR pathway that promotes AR degradation via the proteasome that may offer novel therapeutic opportunities for prostate cancer. Mol Cancer Res; 15(8); 1063-72. ©2017 AACR . ©2017 American Association for Cancer Research.

  9. First evidence of patchy flickering aurora modulated by multi-ion electromagnetic ion cyclotron waves

    Science.gov (United States)

    Fukuda, Yoko; Kataoka, Ryuho; Uchida, Herbert Akihito; Miyoshi, Yoshizumi; Hampton, Donald; Shiokawa, Kazuo; Ebihara, Yusuke; Whiter, Daniel; Iwagami, Naomoto; Seki, Kanako

    2017-05-01

    Electromagnetic ion cyclotron (EMIC) waves, one of the possible origins of flickering aurora, have been thought to modulate the electron flux at a few thousand kilometers. In fact, flickering aurora with a frequency range of 3-15 Hz has often been identified by ground-based optical observations and has been interpreted to be caused by O+-band EMIC waves. However, extant research to date has not identified possible signatures of H+-band EMIC waves due to technical limitations of ground-based high-speed imagers. The present study shows the first evidence that patchy flickering aurora could be modulated by H+-band EMIC waves, based on the data obtained from imaging observations at 160 frames per second. The sporadic appearance of the flickering aurora in the frequency range of 50-80 Hz coexisted with typical flickering auroras of approximately 10 Hz. These results are consistent with the hypothesis that flickering auroras are generated by multi-ion EMIC waves.

  10. TL glow curve analysis of UV, beta and gamma induced limestone collected from Amarnath holy cave

    Directory of Open Access Journals (Sweden)

    Vikas Dubey

    2015-01-01

    Full Text Available The paper reports themoluminescence glow curve analysis of UV (ultraviolet, β (beta and γ (gamma induced limestone collected from Amarnath holy cave. The collected natural sample was characterized by X-ray diffraction (XRD technique and crystallite size calculated by Scherer's formula. Surface morphology and particle size was calculated by transmission electron microscopy (TEM study. Effect of annealing temperature on collected lime stone examined by TL glow curve study. The limestone was irradiated by UV radiation (254 nm source and the TL glow curve recorded for different UV exposure time. For beta irradiation Sr90 source was used and is shows intense peak at 256 °C with a shoulder peak at higher temperature range. For gamma radiation Co60 source and TL glow curve recorded for different doses of gamma. The kinetic parameters calculation was performed for different glow curve by computerized glow curve deconvolution (CGCD technique. The chemical composition of natural limestone was analyzed by energy dispersive X-ray spectroscopy (EDXS.

  11. Study of the glow curve structure of the minerals separated from black pepper (Piper nigrum L.)

    Science.gov (United States)

    Guzmán, S.; Ruiz Gurrola, B.; Cruz-Zaragoza, E.; Tufiño, A.; Furetta, C.; Favalli, A.; Brown, F.

    2011-04-01

    The inorganic mineral fraction extracted from black pepper (Piper nigrum L.) has been analysed using a thermoluminescence (TL) method, investigating the glow curve structure, including an evaluation of the kinetic parameters. Different grain sizes, i.e. 10, 74, and 149 μm, were selected from commercial black pepper. The X-ray diffraction of the inorganic fraction shows that quartz is the main mineral present in it. The samples were exposed to 1-25 kGy doses by gamma rays of 60Co in order to analyse the thermally stimulated luminescence response as a function of the delivered dose. The glow curves show a complex structure for different grain sizes of the pepper mineral samples. The fading of the TL signal at room temperature was obtained after irradiation, and it was observed that the maximum peaks of the glow curves shift towards higher values of the temperature when the elapsed time from irradiation increases. It seems that the fading characteristic may be related to a continuous trap distribution responsible for the complex structure of the glow curve. Similar glow curves structure behaviour was found under ultraviolet irradiation of the samples. The activation energy and the frequency factor were determined from the glow curves of different grain sizes using a deconvolution programme because of the evident complexity of the structure.

  12. Low Pressure DC Glow Discharge Air Plasma Surface Treatment of Polyethylene (PE) Film for Improvement of Adhesive Properties

    International Nuclear Information System (INIS)

    Pandiyaraj, Krishnasamy Navaneetha; Yoganand, Paramasivam; Selvarajan, Vengatasamy; Deshmukh, Rajendrasing R.; Balasubramanian, Suresh; Maruthamuthu, Sundaram

    2013-01-01

    The present work deals with the change in surface properties of polyethylene (PE) film using DC low pressure glow discharge air plasma and makes it useful for technical applications. The change in hydrophilicity of the modified PE film surface was investigated by measuring contact angle and surface energy as a function of exposure time. Changes in the morphological and chemical composition of PE films were analyzed by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The improvement in adhesion was studied by measuring T-peel and lap-shear strength. The results show that the wettability and surface energy of the PE film has been improved due to the introduction of oxygen-containing polar groups and an increase in surface roughness. The XPS result clearly shows the increase in concentration of oxygen content and the formation of polar groups on the polymer surface. The AFM observation on PE film shows that the roughness of the surface increased due to plasma treatment. The above morphological and chemical changes enhanced the adhesive properties of the PE film surfaces, which was confirmed by T-peel and lap-shear tests.

  13. Influence of dust particles on DC glow discharge plasma

    Science.gov (United States)

    Liang, Yonggan; Yuan, Chengxun; Li, Hui; Tian, Ruihuan; Wu, Jian; Kudryavtsev, A. A.; Zhou, Zhongxiang; Tian, Hao

    2018-02-01

    The effect of dust particles on DC glow discharge plasma parameters is studied numerically through the development of a self-consistent model based on the extended fluid approach. The orbital motion limited theory and collision enhanced collection approximation are employed to describe the charging processes of dust particles with various sizes and densities. The uniform distribution of dust particles in plasma and the instantaneous charging process were assumed during simulations. The influence of dust particle size rd and density Nd on gas discharge and dust particle parameters is investigated systematically. It is shown that the plasma parameters can be affected obviously by the dust particles. The increase in the values of rd and Nd leads to the decrease in the dust particle charge number, electron, and ion density. Meanwhile, the appearance of dust particles leads to an obvious increase in the averaged plasma electric field and electron temperature to sustain the discharge in the dust region. The dust particles are proven to be a very efficient way to artificially manipulate gas discharge parameters.

  14. Bulk plasma properties in the pulsed glow discharge

    International Nuclear Information System (INIS)

    Jackson, Glen P.; King, Fred L.

    2003-01-01

    This work focuses on the spatial and temporal characteristics of a glow discharge plasma operated with power pulses of 5 ms in duration at 25% duty cycle. Interpretation of emission data provides insight into the nature of the plasma at each instant of a typical pulse cycle and at each position in space. Because the bulk plasma properties affect the distribution of excited energy levels of the sputtered atoms, an improved understanding of the plasma affords the ability to select conditions that enhance analytically important emission lines. Optical emission spectroscopy was used to determine the relative populations of excited states for atoms and ions during the initial breakdown, the steady state and the recombining periods of the discharge pulse cycle. The plasma is highly ionizing in nature at the time of breakdown--with lower excited states being overpopulated--before reaching the steady state, or plateau, period, also ionizing in nature. These behaviors arise from a loss of charged particles and photons to the surroundings that shifts the plasma away from Saha and Boltzmann balances during these periods. The post-pulse period typically displays recombining behavior, characterized by population inversion for selected species--except for regions close to the cathode, where electrons and ions are lost by diffusion and are not available for recombination. The sputtered analyte atom emissions closely mimic those of the plasma bath gas, except that their emissions persevere for longer in the recombining after-peak period than do the discharge gas species

  15. Indomethacin promotes apoptosis in gastric cancer cells through concomitant degradation of Survivin and Aurora B kinase proteins.

    Science.gov (United States)

    Chiou, Shiun-Kwei; Hoa, Neil; Hodges, Amy; Ge, Lishen; Jadus, Martin R

    2014-09-01

    Regular usage of nonsteroidal anti-inflammatory drugs (NSAIDs) is associated with reduced incidence of a variety of cancers. The molecular mechanisms underlying these chemopreventive effects remain poorly understood. This current investigation showed that in gastric cancer cells: (1) Indomethacin treatment enhanced the degradation of chromosomal passenger proteins, Survivin and Aurora B kinase; (2) Indomethacin treatment down-regulated Aurora B kinase activity in a cell cycle-independent fashion; (3) siRNA knockdown of Survivin level promoted Aurora B kinase protein degradation, and vice versa; (4) ectopic overexpression of Survivin blocked reduction of Aurora B kinase level and activity by indomethacin treatment, and vice versa; (5) siRNA knockdown of Aurora B kinase level and AZD1152 inhibition of its activity induced apoptosis, and overexpression of Aurora B kinase inhibited indomethacin-induced apoptosis; (6) indomethacin treatment reduced Aurora B kinase level, coinciding with reduction of Survivin level and induction of apoptosis, in KATO III and HT-29 cells, and in mouse gastric mucosa. A role for Aurora B kinase function in NSAID-induced apoptosis was not previously explored. Thus this report provides better understanding of the molecular mechanisms underlying the anti-cancer effect of NSAIDs by elucidating a significant role for Aurora B kinase in indomethacin-induced apoptosis.

  16. P21-activated kinase 7 mediates cisplatin-resistance of esophageal squamous carcinoma cells with Aurora-A overexpression.

    Directory of Open Access Journals (Sweden)

    Shun He

    Full Text Available Aurora-A overexpression is common in various types of cancers and has been shown to be involved in tumorigenesis through different signaling pathways, yet how the deregulation affects cancer therapeutics remains elusive. Here we showed that overexpression of Aurora-A rendered esophageal cancer cells resistance to cisplatin (CDDP by inhibiting apoptosis. By using an apoptosis array, we identified a downstream gene, p21-activated kinase 7 (PAK7. PAK7 was upregulated by Aurora-A overexpression at both mRNA and protein levels. Importantly, the expression levels of Aurora-A and PAK7 were correlated in ESCC primary samples. Chromatin immunoprecipitation (ChIP assay revealed that binding of E2F1 to the promoter of PAK7 was significantly enhanced upon Aurora-A activation, and knockdown of transcription factor E2F1 decreased PAK7 expression, suggesting that Aurora-A regulated PAK7 through E2F1. Furthermore, we demonstrated that PAK7 knockdown led to increased apoptosis, and Aurora-A-induced resistance to CDDP was reversed by downregulation of PAK7, suggesting PAK7 was a downstream player of Aurora-A that mediated chemoresistance of ESCC cells to CDDP. Our data suggest that PAK7 may serve as an attractive candidate for therapeutics in ESCC patients with Aurora-A abnormality.

  17. GPS scintillations associated with cusp dynamics and polar cap patches

    Directory of Open Access Journals (Sweden)

    Jin Yaqi

    2017-01-01

    Full Text Available This paper investigates the relative scintillation level associated with cusp dynamics (including precipitation, flow shears, etc. with and without the formation of polar cap patches around the cusp inflow region by the EISCAT Svalbard radar (ESR and two GPS scintillation receivers. A series of polar cap patches were observed by the ESR between 8:40 and 10:20 UT on December 3, 2011. The polar cap patches combined with the auroral dynamics were associated with a significantly higher GPS phase scintillation level (up to 0.6 rad than those observed for the other two alternatives, i.e., cusp dynamics without polar cap patches, and polar cap patches without cusp aurora. The cusp auroral dynamics without plasma patches were indeed related to GPS phase scintillations at a moderate level (up to 0.3 rad. The polar cap patches away from the active cusp were associated with sporadic and moderate GPS phase scintillations (up to 0.2 rad. The main conclusion is that the worst global navigation satellite system space weather events on the dayside occur when polar cap patches enter the polar cap and are subject to particle precipitation and flow shears, which is analogous to the nightside when polar cap patches exit the polar cap and enter the auroral oval.

  18. GPS scintillations associated with cusp dynamics and polar cap patches

    Science.gov (United States)

    Jin, Yaqi; Moen, Jøran I.; Oksavik, Kjellmar; Spicher, Andres; Clausen, Lasse B. N.; Miloch, Wojciech J.

    2017-10-01

    This paper investigates the relative scintillation level associated with cusp dynamics (including precipitation, flow shears, etc.) with and without the formation of polar cap patches around the cusp inflow region by the EISCAT Svalbard radar (ESR) and two GPS scintillation receivers. A series of polar cap patches were observed by the ESR between 8:40 and 10:20 UT on December 3, 2011. The polar cap patches combined with the auroral dynamics were associated with a significantly higher GPS phase scintillation level (up to 0.6 rad) than those observed for the other two alternatives, i.e., cusp dynamics without polar cap patches, and polar cap patches without cusp aurora. The cusp auroral dynamics without plasma patches were indeed related to GPS phase scintillations at a moderate level (up to 0.3 rad). The polar cap patches away from the active cusp were associated with sporadic and moderate GPS phase scintillations (up to 0.2 rad). The main conclusion is that the worst global navigation satellite system space weather events on the dayside occur when polar cap patches enter the polar cap and are subject to particle precipitation and flow shears, which is analogous to the nightside when polar cap patches exit the polar cap and enter the auroral oval.

  19. Juno-UVS approach observations of Jupiter's auroras.

    Science.gov (United States)

    Gladstone, G R; Versteeg, M H; Greathouse, T K; Hue, V; Davis, M W; Gérard, J-C; Grodent, D C; Bonfond, B; Nichols, J D; Wilson, R J; Hospodarsky, G B; Bolton, S J; Levin, S M; Connerney, J E P; Adriani, A; Kurth, W S; Mauk, B H; Valek, P; McComas, D J; Orton, G S; Bagenal, F

    2017-08-16

    Juno ultraviolet spectrograph (UVS) observations of Jupiter's aurora obtained during approach are presented. Prior to the bow shock crossing on 24 June 2016, the Juno approach provided a rare opportunity to correlate local solar wind conditions with Jovian auroral emissions. Some of Jupiter's auroral emissions are expected to be controlled or modified by local solar wind conditions. Here we compare synoptic Juno-UVS observations of Jupiter's auroral emissions, acquired during 3-29 June 2016, with in situ solar wind observations, and related Jupiter observations from Earth. Four large auroral brightening events are evident in the synoptic data, in which the total emitted auroral power increases by a factor of 3-4 for a few hours. Only one of these brightening events correlates well with large transient increases in solar wind ram pressure. The brightening events which are not associated with the solar wind generally have a risetime of ~2 h and a decay time of ~5 h.

  20. Ezekiel and the Northern Lights: Biblical aurora seems plausible

    Science.gov (United States)

    Siscoe, George L.; Silverman, Samuel M.; Siebert, Keith D.

    Auroral specialists have suggested that in the Bible's Old Testament book of Ezekiel, the opening vision of a "storm cloud out of the north" depicts imagery inspired by a low-latitude auroral display [Link, 1967; Eather, 1980; Silverman, 1998]. Naturally, other interpretations have been suggested, including a true epiphany, a sandstorm, a thunderstorm, a tornado, a solar halo, a hallucination, and a UFO. Biblical scholars place the site of the Ezekiel's vision about 100 km south of Babylon near Nippur, latitude ˜32°, longitude ˜45°, and the date is within a year or two of 593 B.C., or about 2600 years ago.An auroral interpretation of the vision is subject to possible refutation due to several geophysical considerations. Can auroras be seen at Ezekiel's latitude? More important, can they reach a coronal stage of development, which is what the vision requires? Was the tilt of the dipole axis favorable? Was the general level of solar activity favorable? And finally, What effect does a larger dipole moment in Ezekiel's time have on the question? All but the last question could have been answered on the basis of geophysical data a decade ago or earlier.

  1. Parallel electric fields inferred during a pulsating aurora

    Directory of Open Access Journals (Sweden)

    J. D. Williams

    2006-08-01

    Full Text Available A sounding rocket, equipped to study pulsating aurora launched from Poker Flat, Alaska on 13 March 1997 at 10:20:31 UT, measured electron precipitation over the range ~10 eV to 500 keV covering pitch-angles from 0 to 180°. Data show electrons with energies <1 keV are mostly secondaries produced below the rocket altitude by the higher energy precipitated electrons. We observed nearly equal fluxes of up and down going electrons for energies <1 keV at altitudes from 265 to 380 km. Electron transport simulation results indicate the secondaries produced by the more energetic electrons will have two times higher flux in the upward direction as compared to the downward direction. Our observations of nearly equal fluxes of up and downgoing electrons over a large range of altitudes is consistent with the presence of an electric potential above the rocket that reflects the upgoing electrons back toward the rocket where they are detected as downward going electrons. The strength of the potential is estimated to be 1.5±0.5 kV and its location is no greater than 5000km above the rocket. Finally, the inferred potential drop exists independently of the presence of pulsations.

  2. Juno‐UVS approach observations of Jupiter's auroras

    Science.gov (United States)

    Versteeg, M. H.; Greathouse, T. K.; Hue, V.; Davis, M. W.; Gérard, J.‐C.; Grodent, D. C.; Bonfond, B.; Nichols, J. D.; Wilson, R. J.; Hospodarsky, G. B.; Bolton, S. J.; Levin, S. M.; Connerney, J. E. P.; Adriani, A.; Kurth, W. S.; Mauk, B. H.; Valek, P.; McComas, D. J.; Orton, G. S.; Bagenal, F.

    2017-01-01

    Abstract Juno ultraviolet spectrograph (UVS) observations of Jupiter's aurora obtained during approach are presented. Prior to the bow shock crossing on 24 June 2016, the Juno approach provided a rare opportunity to correlate local solar wind conditions with Jovian auroral emissions. Some of Jupiter's auroral emissions are expected to be controlled or modified by local solar wind conditions. Here we compare synoptic Juno‐UVS observations of Jupiter's auroral emissions, acquired during 3–29 June 2016, with in situ solar wind observations, and related Jupiter observations from Earth. Four large auroral brightening events are evident in the synoptic data, in which the total emitted auroral power increases by a factor of 3–4 for a few hours. Only one of these brightening events correlates well with large transient increases in solar wind ram pressure. The brightening events which are not associated with the solar wind generally have a risetime of ~2 h and a decay time of ~5 h. PMID:28989207

  3. Characterization of cadmium uptake by the water lily Nymphaea aurora.

    Science.gov (United States)

    Schor-Fumbarov, Tamar; Keilin, Zvika; Tel-Or, Elisha

    2003-01-01

    This study characterizes cadmium (Cd) uptake by the waterlily Nymphaea aurora, (Nymphaeaceae) in two systems: a model hydroponic Cd solution and heavily polluted sludge from two sites in Israel. The uptake of Cd from hydroponic solution resulted in Cd storage in petioles and laminae of Nymphaea, as well as in the roots. The pH of the solution affected Cd solubility and availability, with pH 5.5 yielding maximum Cd content in the plant (140 mg Cd per g DW). Cd uptake was reduced by the addition of EDTA to the hydroponic growth medium, although EDTA enhanced heavy metal uptake by terrestrial plants. Nymphaea efficiently reduced the concentration of Cd in heavy metal polluted urban and industrial sludge and the amount of Cd uptake was enhanced by the addition of KCl to the sludge and by adjustment of the pH to 5.5. The inherent growth patterns of Nymphaea plants allowed Cd uptake by the shoot and root, and resulted in maximum contact between the various plant parts and the growth media. Thus, Nymphaea has potential as an optimal, highly effective phytoremediation tool for the removal of Cd from polluted waste sources.

  4. Distribution of positive ion species above a diffuse midnight aurora

    International Nuclear Information System (INIS)

    Moore, T.E.

    1978-01-01

    The origin of the hot plasma in the Earth's magnetosphere is still open to investigation. Mass composition is an indicator of source region, while the distribution functions bear the signatures of transport and energization processes. Only ions identified as H + and He ++ were detected, and the He ++ was statistically marginal. Coincident magnetic storms are likely to play a crucial role in populating the magnetosphere with energized ionospheric ions. The measured proton distribution was nearly isotropic over downcoming pitch angles at all energies and showed a depleted atmospheric source cone. The high-altitude proton energy distribution had a best fit temperature of 4.5 keV and a number density of 0.17 cm- 3 , corresponding to a peak intensity just over 10 5 cm -2 s -1 sr -1 keV -1 . Altitudinal variations are consistent with the theory of charge exchange of a time-steady incident proton population. Simultaneous electron measurements can be interpreted in terms of an incident electron distribution that is also thermal wih a similar number density but a temperature of 2.5 keV. Taken together, the ion and electron data are consistent with the model of diffuse auroras in which plasma convecting in from the magnetospheric tail precipitates due to strong pitch angle diffusion on auroral field lines linking the near Earth plasma sheet

  5. Second approximation structural assessment of the Aurora solar sail spacecraft

    Science.gov (United States)

    Genta, G.; Brusa, E.; Delprete, C.

    2004-01-01

    Aurora spacecraft is a scientific probe propelled by a "fast" solar sail whose first goal is to perform a technology assessment mission. A key point of the experiment is the possibility of building a very light structure in order to achieve a high speed with the very low force due to the pressure of solar light. This in turn implies the need to perform a very accurate stress analysis of the whole structure. A first approximation study allowed one to verify that the structural goals that were stated in the preliminary design can be met. The aim of the present paper is to build a complete mathematical model based on the finite element method (FEM) of the whole spacecraft allowing to perform a detailed stress analysis of the various components and to compute the inflected shape of the sail. The code that has been developed can take into account the effects of the thermal expansion of the sail and of the spacecraft acceleration and can be adapted to solar sail spacecraft with different geometrical configurations.

  6. Aurora 7 the Mercury space flight of M. Scott Carpenter

    CERN Document Server

    Burgess, Colin

    2016-01-01

    TO A NATION enthralled by the heroic exploits of the Mercury astronauts, the launch of Lt. Cmdr. Scott Carpenter on NASA’s second orbital space flight was a renewed cause for pride, jubilation and celebration. Within hours, that excitement had given way to stunned disbelief and anxiety as shaken broadcasters began preparing the American public for the very real possibility that an American astronaut and his spacecraft may have been lost at sea. In fact, it had been a very close call. Completely out of fuel and forced to manually guide Aurora 7 through the frightening inferno of re-entry, Carpenter brought the Mercury spacecraft down to a safe splashdown in the ocean. In doing so, he controversially overshot the intended landing zone. Despite his efforts, Carpenter’s performance on the MA-7 mission was later derided by powerful figures within NASA. He would never fly into space again. Taking temporary leave of NASA, Carpenter participated in the U.S. Navy’s pioneering Sealab program. For a record 30 days...

  7. Differential Selective Pressures Experienced by the Aurora Kinase Gene Family

    Directory of Open Access Journals (Sweden)

    Joni M. Seeling

    2017-12-01

    Full Text Available Aurora kinases (AKs are serine/threonine kinases that are essential for cell division. Humans have three AK genes: AKA, AKB, and AKC. AKA is required for centrosome assembly, centrosome separation, and bipolar spindle assembly, and its mutation leads to abnormal spindle morphology. AKB is required for the spindle checkpoint and proper cytokinesis, and mutations cause chromosome misalignment and cytokinesis failure. AKC is expressed in germ cells, and has a role in meiosis analogous to that of AKB in mitosis. Mutation of any of the three isoforms can lead to cancer. AK proteins possess divergent N- and C-termini and a conserved central catalytic domain. We examined the evolution of the AK gene family using an identity matrix and by building a phylogenetic tree. The data suggest that AKA is the vertebrate ancestral gene, and that AKB and AKC resulted from gene duplication in placental mammals. In a nonsynonymous/synonymous rate substitution analysis, we found that AKB experienced the strongest, and AKC the weakest, purifying selection. Both the N- and C-termini and regions within the kinase domain experienced differential selection among the AK isoforms. These differentially selected sequences may be important for species specificity and isoform specificity, and are therefore potential therapeutic targets.

  8. Antineoplastic effects of an Aurora B kinase inhibitor in breast cancer

    Directory of Open Access Journals (Sweden)

    Velazquez-Torres Guermarie

    2010-02-01

    Full Text Available Abstract Background Aurora B kinase is an important mitotic kinase involved in chromosome segregation and cytokinesis. It is overexpressed in many cancers and thus may be an important molecular target for chemotherapy. AZD1152 is the prodrug for AZD1152-HQPA, which is a selective inhibitor of Aurora B kinase activity. Preclinical antineoplastic activity of AZD1152 against acute myelogenous leukemia, multiple myeloma and colorectal cancer has been reported. However, this compound has not been evaluated in breast cancer, the second leading cause of cancer deaths among women. Results The antineoplastic activity of AZD1152-HQPA in six human breast cancer cell lines, three of which overexpress HER2, is demonstrated. AZD1152-HQPA specifically inhibited Aurora B kinase activity in breast cancer cells, thereby causing mitotic catastrophe, polyploidy and apoptosis, which in turn led to apoptotic death. AZD1152 administration efficiently suppressed the tumor growth in a breast cancer cell xenograft model. In addition, AZD1152 also inhibited pulmonary metastatic nodule formation in a metastatic breast cancer model. Notably, it was also found that the protein level of Aurora B kinase declined after inhibition of Aurora B kinase activity by AZD1152-HQPA in a time- and dose-dependent manner. Investigation of the underlying mechanism suggested that AZD1152-HQPA accelerated protein turnover of Aurora B via enhancing its ubiquitination. Conclusions It was shown that AZD1152 is an effective antineoplastic agent for breast cancer, and our results define a novel mechanism for posttranscriptional regulation of Aurora B after AZD1152 treatment and provide insight into dosing regimen design for this kinase inhibitor in metastatic breast cancer treatment.

  9. In-flight observation of long duration gamma-ray glows by aircraft

    Science.gov (United States)

    Kochkin, Pavlo; (Lex) van Deursen, A. P. J.; de Boer, Alte; Bardet, Michiel; Allasia, Cedric; Boissin, Jean Francois; Ostgaard, Nikolai

    2017-04-01

    The Gamma-Ray Glow is a long-lasting (several seconds to minutes) X- and gamma radiation presumably originated from high-electric field of thunderclouds. Such glows were previously observed by aircraft, balloons, and from the ground. When detected on ground with other particles, i.e. electrons and neutrons, they are usually called Thunderstorm Ground Enhancements (TGEs). Their measured spectra are often consistent with Relativistic Runaway Electron Avalanche (RREA) mechanism. That is why RREA is a commonly accepted explanation for their existence. The gamma-ray glows are observed to be interrupted by lightning discharge, which terminates the high-electric field region. In January 2016 an Airbus A340 factory test aircraft was performing intentional flights through thunderstorms over Northern Australia. The aircraft was equipped with a dedicated in-flight lightning detection system called ILDAS (http://ildas.nlr.nl). The system also contained two scintillation detectors each with 38x38 mm cylinder LaBr3 crystals. While being at 12 km altitude the system detected a gamma-ray flux enhancement 30 times the background counts. It lasted for 20 seconds and was abruptly terminated by a lightning flash. The flash hit the aircraft and its parameters were recorded with 10 ns sampling time including gamma radiation. Ground-based lightning detection network WWLLN detected 4 strikes in the nearby region, all in association with the same flash. The ILDAS system recorded the time-resolved spectrum of the glow. In 6 minutes, after making a U-turn, the aircraft passed the same glow region. Smaller gamma-ray enhancement was again detected. In this presentation we will show the mapped event timeline including airplane, gamma-ray glow, WWLLN, and cloud data. We will discuss the glow's properties, i.e. intensity and differential spectrum, and its possible origin. This result will also be compared to previously reported observations.

  10. Polarization developments

    International Nuclear Information System (INIS)

    Prescott, C.Y.

    1993-07-01

    Recent developments in laser-driven photoemission sources of polarized electrons have made prospects for highly polarized electron beams in a future linear collider very promising. This talk discusses the experiences with the SLC polarized electron source, the recent progress with research into gallium arsenide and strained gallium arsenide as a photocathode material, and the suitability of these cathode materials for a future linear collider based on the parameters of the several linear collider designs that exist

  11. Auroral and magnetic variations in the polar cusp and cleft. Signatures of magnetopause boundary layer dynamics

    International Nuclear Information System (INIS)

    Sandholt, P.E.; Egeland, A.

    1987-10-01

    By combining continous ground-based observations of polar cleft/cusp auroras and local magnetic variations with electromagnetic parameters obtained from satellites in polar orbit (low-altitude cleft/cusp) and in the magnetosheath/interplanetary space, different electrodynamic processes in the polar cleft/cusp have been investigated. One of the more controversial questions in this field is related to the observed shifts in latitude of cleft/cusp auroras and the relationships with the interplanetary magnetic field (IMF) orientation, local magnetic disturbances (DP2 and DPY modes) and magnetospheric substorms. A new approach which may contribute to clarifying these complicated relationships, simultaneous groundbased observations of the midday and evening-midnight sectors of the auroral oval, is illustrated. A related topic is the spatial relationship between the cleft/cusp auroras and the ionospheric convection currents. A characteristic feature of the polar cusp and cleft regions during negative IMF B z is repeated occurrence of certain short-lived auroral structures moving in accordance with the local convection pattern. Satellite measurements of particle precipitation, magnetic field and ion drift components permit detailed investigations of the electrodynamics of these cusp/cleft structures. Information on electric field components, Birkeland currents, Poynting flux, height-integrated Pedersen conductivity and Joule heat dissipation rate has been derived. These observations are discussed in relation to existing models of temporal plasma injections from the magnetosheath

  12. Analysis of soils by glow discharge mass spectrometry

    International Nuclear Information System (INIS)

    Duckworth, D.C.; Barshick, C.M.; Smith, D.H.

    1993-01-01

    The analysis of soils by conventional solution-based techniques, such as inductively coupled plasma and thermal ionization mass spectrometry, is complicated by the need for sample dissolution or the combination of a solids atomizer with an auxiliary ionization source. Since time is an important consideration in waste remediation, there exists a need for a method of rapidly analysing many soil samples with little sample preparation; glow discharge mass spectrometry (GDMS) has the potential to meet this need. Because GDMS is a bulk solids technique, sample preparation is simplified in comparison to other methods. Even with the most difficult samples (geological materials, such as soils and volcanic rock), all that is required is grinding, drying and mixing with a conducting host material prior to electrode formation. As a first test of GDMS for soil analysis, a National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) was analysed by direct current GDMS. Fifty-one elements were quantified from a single cathode using ion beam ratios and ''standard'' relative elemental sensitivity factors (RSF). Average errors for the suite of elements were less than a factor of 4 and 1.4 for uncorrected and corrected values, respectively. User-generated RSF values were applied to the analysis of several elements in NIST SRM 2704 Buffalo River Sediment. In the absence of isobaric interferences, accuracies ranging from 0.6 to 73% were observed, demonstrating the potential of the technique for the determination of many elements. The presence of entrained water and inhomogeneity resulting from cathode preparation is thought to affect matrix-to-matrix reproducibility. While further success depends on developing means of circumventing mass spectral interferences and addressing factors affecting plasma chemistry, the immediate goal of developing a screening method for priority metals in soils was met. (Author)

  13. Selective disruption of aurora C kinase reveals distinct functions from aurora B kinase during meiosis in mouse oocytes.

    Directory of Open Access Journals (Sweden)

    Ahmed Z Balboula

    2014-02-01

    Full Text Available Aurora B kinase (AURKB is the catalytic subunit of the chromosomal passenger complex (CPC, an essential regulator of chromosome segregation. In mitosis, the CPC is required to regulate kinetochore microtubule (K-MT attachments, the spindle assembly checkpoint, and cytokinesis. Germ cells express an AURKB homolog, AURKC, which can also function in the CPC. Separation of AURKB and AURKC function during meiosis in oocytes by conventional approaches has not been successful. Therefore, the meiotic function of AURKC is still not fully understood. Here, we describe an ATP-binding-pocket-AURKC mutant, that when expressed in mouse oocytes specifically perturbs AURKC-CPC and not AURKB-CPC function. Using this mutant we show for the first time that AURKC has functions that do not overlap with AURKB. These functions include regulating localized CPC activity and regulating chromosome alignment and K-MT attachments at metaphase of meiosis I (Met I. We find that AURKC-CPC is not the sole CPC complex that regulates the spindle assembly checkpoint in meiosis, and as a result most AURKC-perturbed oocytes arrest at Met I. A small subset of oocytes do proceed through cytokinesis normally, suggesting that AURKC-CPC is not the sole CPC complex during telophase I. But, the resulting eggs are aneuploid, indicating that AURKC is a critical regulator of meiotic chromosome segregation in female gametes. Taken together, these data suggest that mammalian oocytes contain AURKC to efficiently execute meiosis I and ensure high-quality eggs necessary for sexual reproduction.

  14. Rebamipide inhibits gastric cancer growth by targeting survivin and Aurora-B

    International Nuclear Information System (INIS)

    Tarnawski, A.; Pai, R.; Chiou, S.-K.; Chai, J.; Chu, E.C.

    2005-01-01

    Rebamipide accelerates healing of gastric ulcers and gastritis but its actions on gastric cancer are not known. Survivin, an anti-apoptosis protein, is overexpressed in stem, progenitor, and cancer cells. In gastric cancer, increased and sustained survivin expression provides survival advantage and facilitates tumor progression and resistance to anti-cancer drugs. Aurora-B kinase is essential for chromosome alignment and mitosis progression but surprisingly its role in gastric cancer has not been explored. We examined in human gastric cancer AGS cells: (1) survivin expression, (2) localization of survivin and Aurora-B (3) cell proliferation, and (4) effects of specific survivin siRNA and/or rebamipide (free radical scavenging drug) on survivin and Aurora-B expression and cell proliferation. Survivin and Aurora-B are strongly expressed in human AGS gastric cancer cells and co-localize during mitosis. Survivin siRNA significantly reduces AGS cell viability. Rebamipide significantly downregulates in AGS cell survivin expression, its association with Aurora-B and cell proliferation. Rebamipide-induced downregulation of survivin is at the transcription level and does not involve ubiquitin-proteasome pathway

  15. Combined cisplatin and aurora inhibitor treatment increase neuroblastoma cell death but surviving cells overproduce BDNF

    Directory of Open Access Journals (Sweden)

    Alessio Polacchini

    2016-07-01

    Full Text Available Drug-resistance to chemotherapics in aggressive neuroblastoma (NB is characterized by enhanced cell survival mediated by TrkB and its ligand, brain-derived neurotrophic factor (BDNF; thus reduction in BDNF levels represent a promising strategy to overcome drug-resistance, but how chemotherapics regulate BDNF is unknown. Here, cisplatin treatment in SK-N-BE neuroblastoma upregulated multiple BDNF transcripts, except exons 5 and 8 variants. Cisplatin increased BDNF mRNA and protein, and enhanced translation of a firefly reporter gene flanked by BDNF 5′UTR exons 1, 2c, 4 or 6 and 3′UTR-long. To block BDNF translation we focused on aurora kinases inhibitors which are proposed as new chemotherapeutics. NB cell survival after 24 h treatment was 43% with cisplatin, and 22% by cisplatin+aurora kinase inhibitor PHA-680632, while the aurora kinases inhibitor alone was less effective; however the combined treatment induced a paradoxical increase of BDNF in surviving cells with strong translational activation of exon6-3′UTR-long transcript, while translation of BDNF transcripts 1, 2C and 4 was suppressed. In conclusion, combined cisplatin and aurora kinase inhibitor treatment increases cell death, but induces BDNF overproduction in surviving cells through an aurora kinase-independent mechanism.

  16. Validation of Aurora Solar Inc.'s Envision Software Capabilities

    Energy Technology Data Exchange (ETDEWEB)

    2017-04-03

    As part of the Department of Energy's SunShot Incubator program, Aurora has worked to develop a web-based application that quickly and precisely calculates the solar potential of a building's roof. The Aurora Envision platform utilizes Google StreetView photos as a basis for measuring roof slope and linear measurements of determining the proper inputs into an eventual shade model. The stated accuracy by Aurora Solar to be tested is lengths within 1.5 feet and slope measurements within 5 degrees. The National Renewable Energy Laboratory (NREL), in partnership with Aurora and supported by the U.S. Department of Energy's (DOE) SunShot Technology to Market Incubator program, independently verified the accuracy of Aurora's Envision measurements on 15 unique roofs throughout the Denver, Colorado region. NREL measured 60 measurements: 27 of 28 slope measurements were within the stated accuracy, 32 of 32 distance measurements were within the stated accuracy.

  17. The role of magnetic energy on plasma localization during the glow discharge under reduced pressure

    Directory of Open Access Journals (Sweden)

    Chodun Rafal

    2016-06-01

    Full Text Available In this work, we present the first results of our research on the synergy of fields, electric and magnetic, in the initiation and development of glow discharge under reduced pressure. In the two-electrode system under reduced pressure, the breakdown voltage characterizes a minimum energy input of the electric field to initiate and sustain the glow discharge. The glow discharge enhanced by the magnetic field applied just above the surface of the cathode influences the breakdown voltage decreasing its value. The idea of the experiment was to verify whether the contribution of potential energy of the magnetic field applied around the cathode is sufficiently effective to locate the plasma of glow discharge to the grounded cathode, which, in fact, is the part of a vacuum chamber wall (the anode is positively biased in this case. In our studies, we used the grounded magnetron unit with positively biased anode in order to achieve favorable conditions for the deposition of thin films on fibrous substrates such as fabrics for metallization, assuming that locally applied magnetic field can effectively locate plasma. The results of our studies (Paschen curve with the participation of the magnetic field seem to confirm the validity of the research assumption. What is the most spectacular - the glow discharge was initiated between introduced into the chamber anode and the grounded cathode of magnetron ‘assisted’ by the magnetic field (discharge did not include the area of the anode, which is a part of the magnetron construction.

  18. Comparing glow discharge plasma and ultrasound treatment for improving aerobic respiration of activated sludge.

    Science.gov (United States)

    Van de Moortel, Nina; Van den Broeck, Rob; Degrève, Jan; Dewil, Raf

    2017-10-01

    In this paper, a new and innovative technique, glow discharge plasma, is introduced for the treatment of activated sludge, whereby its effect on sludge solubilization, settleability, floc structure and biomass activity for carbon removal and nitrification is investigated. The obtained results are compared to the use of ultrasound for activated sludge treatment, a technique known for its potential to enhancing biomass activity. Results indicate that ultrasound is up to 9 times more efficient in solubilizing activated sludge and disrupting the sludge floc. However, ultrasound has a detrimental effect on sludge settling, even the lowest treatment intensity of 180 kJ/kgMLSS induced a 12% increase in sludge volume index (SVI). Glow discharge plasma on the other hand, improved settleability up to 51%. Glow discharge plasma and ultrasound both positively affect the carbon removal rate. On the long term, extreme conditions even gave rise to a maximum improvement in respiration by 58.6% and 176.5% for a glow discharge plasma and ultrasound treatment. Nitrification, however, was never positively influenced by either of the treatments. Starting from 8297 kJ/kgMLSS for glow discharge plasma and 9000 kJ/kgMLSS for ultrasound, a negative effect on the nitrification rate was found. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Polarization, political

    NARCIS (Netherlands)

    Wojcieszak, M.; Mazzoleni, G.; Barnhurst, K.G.; Ikeda, K.; Maia, R.C.M.; Wessler, H.

    2015-01-01

    Polarization has been studied in three different forms: on a social, group, and individual level. This entry first focuses on the undisputed phenomenon of elite polarization (i.e., increasing adherence of policy positions among the elites) and also outlines different approaches to assessing mass

  20. Polarization holography

    DEFF Research Database (Denmark)

    Nikolova, L.; Ramanujam, P.S.

    Current research into holography is concerned with applications in optically storing, retrieving, and processing information. Polarization holography has many unique properties compared to conventional holography. It gives results in high efficiency, achromaticity, and special polarization...... properties. This books reviews the research carried out in this field over the last 15 years. The authors provide basic concepts in polarization and the propagation of light through anisotropic materials, before presenting a sound theoretical basis for polarization holography. The fabrication...... and characterization of azobenzene based materials, which remain the most efficient for the purpose, is described in detail. This is followed by a description of other materials that are used in polarization holography. An in-depth description of various applications, including display holography and optical storage...

  1. Two Universities and Two Eras of Catholicism in China: Fu Jen University and Aurora University, 1903-1937

    Science.gov (United States)

    Xian, Liu

    2009-01-01

    This paper compares Fu Jen University in Beijing and Aurora University in Shanghai--the two comprehensive Catholic universities located in the two largest cities of China in modern history--and analyzes four aspects: identity, educational idea, curriculum, and campus culture. It was found that the differences between Aurora and Fu Jen resulted…

  2. Computerized glow curve deconvolution of thermoluminescent emission from polyminerals of Jamaica Mexican flower

    Science.gov (United States)

    Favalli, A.; Furetta, C.; Zaragoza, E. Cruz; Reyes, A.

    The aim of this work is to study the main thermoluminescence (TL) characteristics of the inorganic polyminerals extracted from dehydrated Jamaica flower or roselle (Hibiscus sabdariffa L.) belonging to Malvaceae family of Mexican origin. TL emission properties of the polymineral fraction in powder were studied using the initial rise (IR) method. The complex structure and kinetic parameters of the glow curves have been analysed accurately using the computerized glow curve deconvolution (CGCD) assuming an exponential distribution of trapping levels. The extension of the IR method to the case of a continuous and exponential distribution of traps is reported, such as the derivation of the TL glow curve deconvolution functions for continuous trap distribution. CGCD is performed both in the case of frequency factor, s, temperature independent, and in the case with the s function of temperature.

  3. Reduction of Cr(VI) in aqueous solution with DC diaphragm glow discharge

    International Nuclear Information System (INIS)

    Wang, Xiaoyan; Jin, Xinglong; Zhou, Minghua; Chen, Zhenhai; Deng, Kai

    2013-01-01

    This paper investigated the reduction of Cr(VI) in aqueous solution with direct current diaphragm glow discharge (DGD). The glow discharge sustained around the hole on a quartz tube which divided the electrolyte cell into two parts. The reduction efficiencies of Cr(VI) under different applied voltages, initial conductivities, hole diameters, hole numbers, initial pH values and initial concentrations were systematically studied. The results showed that the reduction efficiency of Cr(VI) increased with the increase of applied voltage, initial conductivity, hole diameter and hole number. The different initial pH values showed less effects on the reduction of Cr(VI). The reduction efficiency decreased with the increasing initial concentration. In addition, the simultaneous reduction of Cr(VI) and decolorization of acid orange (AO) with DGD were also fulfilled. Furthermore, the energy efficiency for Cr(VI) reduction with DGD was calculated and compared with those in photocatalysis and other glow discharge reactor

  4. Pre-exponential factor in general order kinetics of thermoluminescence and its influence on glow curves

    International Nuclear Information System (INIS)

    Sunta, C.M.; Ayta, W.E.F.; Chen, R.; Watanabe, S.

    1997-01-01

    A model of thermoluminescence kinetics based on a physically meaningful approach shows that the glow curve shapes undergo systematic changes with the change of trap occupancy (dose). In terms of the general order kinetics model it means that the kinetic order changes with sample dose. In parallel to the kinetic order, the pre-exponential factor also changes. In contrast to these results the glow curves calculated from the general order kinetics model show that the peak shape remains nearly constant when the trap occupancy is changed. When appropriately defined, the pre-exponential factor also has a fixed value independent of trap occupancy. In these respects the general order kinetics model, though empirical, seems to describe the glow peak behaviour quite successfully. However, regarding the peak temperature the theoretical results both from the physical as well as the empirical model seem to diverge from the experimental observations when the experimentally determined kinetics is non-first order. (author)

  5. Detection of negative ions in glow discharge mass spectrometry for analysis of solid specimens

    DEFF Research Database (Denmark)

    Canulescu, Stela; Molchan, Igor S.; Tauziede, C.

    2010-01-01

    A new method is presented for elemental and molecular analysis of halogen-containing samples by glow discharge time-of-flight mass spectrometry, consisting of detection of negative ions from a pulsed RF glow discharge in argon. Analyte signals are mainly extracted from the afterglow regime...... of the discharge, where the cross section for electron attachment increases. The formation of negative ions from sputtering of metals and metal oxides is compared with that for positive ions. It is shown that the negative ion signals of F(-) and TaO(2)F(-) are enhanced relative to positive ion signals and can...... be used to study the distribution of a tantalum fluoride layer within the anodized tantala layer. Further, comparison is made with data obtained using glow-discharge optical emission spectroscopy, where elemental fluorine can only be detected using a neon plasma. The ionization mechanisms responsible...

  6. Heating rate effect on thermoluminescence glow curves of LiF:Mg,Cu,P+PTFE phosphor

    International Nuclear Information System (INIS)

    Cruz-Zaragoza, E.; Gonzalez, P.R.; Azorin, J.; Furetta, C.

    2011-01-01

    The influence of heating rate on the thermoluminescence (TL) property of LiF:Mg,Cu,P+PTFE was analyzed. The activation energy and the frequency factor as a function of the heating rate were determined. The kinetic parameters and their dependence on the heating rate were evaluated using the sequential quadratic programming glow curve deconvolution (SQPGCD). The results showed that as the heating rate increases, the peak intensity at the maximum (I M ) decreases and shifts to higher temperature; similar behavior of the kinetics parameters was observed. - Highlights: →Heating rate influence on the thermoluminescence (TL) property of LiF:Mg,Cu,P was analyzed. → The kinetic parameters, activation energy and frequency factor were evaluated using the sequential quadratic programming glow curve deconvolution. → The peak intensity at the maximum (I M ) of the glow curves decreases. → Shifts to higher temperature were observed as the heating rate increased. → Similar behavior of the kinetics parameters was noticed.

  7. Heating rate effect on thermoluminescence glow curves of LiF:Mg,Cu,P+PTFE phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Cruz-Zaragoza, E. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, A.P. 70-543, Mexico D.F. 04510 (Mexico); Gonzalez, P.R., E-mail: pedro.gonzalez@inin.gob.mx [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca S/N, C.P. 52750, Ocoyoacac, Estado de Mexico (Mexico); Azorin, J. [Universidad Autonoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, 09340 Mexico D.F. (Mexico); Furetta, C. [Touro University Rome, Division of Touro College New York, Circne Gianicolense 15-17, 00153 Rome (Italy)

    2011-10-15

    The influence of heating rate on the thermoluminescence (TL) property of LiF:Mg,Cu,P+PTFE was analyzed. The activation energy and the frequency factor as a function of the heating rate were determined. The kinetic parameters and their dependence on the heating rate were evaluated using the sequential quadratic programming glow curve deconvolution (SQPGCD). The results showed that as the heating rate increases, the peak intensity at the maximum (I{sub M}) decreases and shifts to higher temperature; similar behavior of the kinetics parameters was observed. - Highlights: >Heating rate influence on the thermoluminescence (TL) property of LiF:Mg,Cu,P was analyzed. > The kinetic parameters, activation energy and frequency factor were evaluated using the sequential quadratic programming glow curve deconvolution. > The peak intensity at the maximum (I{sub M}) of the glow curves decreases. > Shifts to higher temperature were observed as the heating rate increased. > Similar behavior of the kinetics parameters was noticed.

  8. Time effectiveness of capillary effect improvement of ramie fabrics processed by RF glow discharging

    International Nuclear Information System (INIS)

    Wang Zhiwen; Wei Weixing; He Yanhe; Zhao Yuanqing; Pan Liyiji; Li Xuemei; Shi Shaodui; Li Guangxin

    2010-01-01

    The time effectiveness of capillary effect improvement of ramie fabrics processed by RF glow discharging was studied. The ramie fabrics were processed in fulfilling with different gas (O 2 , N 2 , Ar) by different parameters (such as pressure,power and time) plasma. The capillary effect of the ramie fabrics processed by RF glow discharging was tested at different time. The results indicate that the capillary effect of ramie fabrics processed by RF glow discharging has been improved, the improvement of the capillary effect firstly decrease rapidly, then slowly, and become stable after 15 day, it indicate that improvement of the ramie fabrics capillary has good time effectiveness, and the plasma parameter for the best capillary effect improvement of ramie fabric is 100 W and 40 Pa processed 20 min by oxygen plasma. (authors)

  9. BOOK REVIEW: Electron acceleration in the aurora and beyond

    Science.gov (United States)

    McClements, K. G.

    1999-08-01

    Duncan Bryant is a retired space plasma physicist who spent most of his career at the Rutherford-Appleton Laboratory in Oxfordshire, England. For many years he has been challenging a widely accepted theory, that auroral electrons are accelerated by double layers, on the grounds that it contains a fundamental error (allegedly, an implicit assumption that charged particles can gain energy from conservative fields). It is, of course, right that models of particle acceleration in natural plasmas should be scrutinized carefully in terms of their consistency with basic physical principles, and I believe that Dr Bryant has performed a valuable service by highlighting this issue. He maintains that auroral electron acceleration by double layers is fundamentally untenable, and that acceleration takes place instead via resonant interactions with lower hybrid waves. In successive chapters, he asserts that essentially the same process can account for electron acceleration observed at the Earth's bow shock, in the neighbourhood of an `artificial comet' produced as part of the Active Magnetospheric Particle Explorers (AMPTE) space mission in 1984/85, in the solar wind, at the Earth's magnetopause, and in the Earth's magneto- sphere. The evidence for this is not always convincing: waves with frequencies of the order of the lower hybrid resonance are often observed in these plasma environments, but in general it is difficult to identify clearly which wave mode is being observed (whistlers, for example, have frequencies in approximately the same range as lower hybrid waves). Moreover, it is not at all clear that the waves which are observed, even if they were of the appropriate type, would have sufficient intensity to accelerate electrons to the extent observed. The author makes a persuasive case, however, that acceleration in the aurora, and in other plasma environments accessible to in situ measurements, involves some form of wave turbulence. In Chapter 2 it is pointed out that

  10. NuMA Phosphorylation by Aurora-A Orchestrates Spindle Orientation.

    Science.gov (United States)

    Gallini, Sara; Carminati, Manuel; De Mattia, Fabiola; Pirovano, Laura; Martini, Emanuele; Oldani, Amanda; Asteriti, Italia Anna; Guarguaglini, Giulia; Mapelli, Marina

    2016-02-22

    Spindle positioning is essential for tissue morphogenesis and homeostasis. The signaling network synchronizing spindle placement with mitotic progression relies on timely recruitment at the cell cortex of NuMA:LGN:Gαi complexes, in which NuMA acts as a receptor for the microtubule motor Dynein. To study the implication of Aurora-A in spindle orientation, we developed protocols for the partial inhibition of its activity. Under these conditions, in metaphase NuMA and Dynein accumulate abnormally at the spindle poles and do not reach the cortex, while the cortical distribution of LGN remains unperturbed. FRAP experiments revealed that Aurora-A governs the dynamic exchange between the cytoplasmic and the spindle pole-localized pools of NuMA. We show that Aurora-A phosphorylates directly the C terminus of NuMA on three Ser residues, of which Ser1969 determines the dynamic behavior and the spindle orientation functions of NuMA. Most interestingly, we identify a new microtubule-binding domain of NuMA, which does not overlap with the LGN-binding motif. Our study demonstrates that in metaphase the direct phosphorylation of NuMA by Aurora-A controls its cortical enrichment, and that this is the major event underlying the spindle orientation functions of Aurora-A in transformed and non-transformed cells in culture. Phosphorylation of NuMA by Aurora-A does not affect its affinity for microtubules or for LGN but rather determines the mobility of the protein at the spindle poles. The finding that NuMA can associate concomitantly with LGN and microtubules suggests that its microtubule-binding activity contributes to anchor Dynein-loaded microtubule +TIPs at cortical sites with LGN. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Discovery of a Previously Unrecognised Allusion to the Aurora Borealis in Paradise Lost, and Implications for Edmund Halley Scholarship

    Science.gov (United States)

    Cunningham, Clifford J.

    2014-11-01

    This research reveals that John Milton employed an allusion to the aurora borealis in the epic poem Paradise Lost which has not been recognised in more than three centuries of scholarly analysis. It further disproves the long-held belief, made popular by the astronomer Edmund Halley, that no notable aurora was visible in England in the seventeenth century. A study of the personal Latin diary of the Elizabethan historian William Camden shows that the famous aurora of 1621 was visible in England. While Pierre Gassendi has been credited with creation of the term 'aurora borealis' based on his report of the 1621 aurora, this study reaffirms a neglected analysis from 1986 that established the term originated with Galileo in 1619.

  12. Polar Bears

    Science.gov (United States)

    Amstrup, Steven C.; Douglas, David C.; Reynolds, Patricia E.; Rhode, E.B.

    2002-01-01

    Polar bears (Ursus maritimus) are hunted throughout most of their range. In addition to hunting polar bears of the Beaufort Sea region are exposed to mineral and petroleum extraction and related human activities such as shipping road-building, and seismic testing (Stirling 1990).Little was known at the start of this project about how polar bears move about in their environment, and although it was understood that many bears travel across political borders, the boundaries of populations had not been delineated (Amstrup 1986, Amstrup et al. 1986, Amstrup and DeMaster 1988, Garner et al. 1994, Amstrup 1995, Amstrup et al. 1995, Amstrup 2000).As human populations increase and demands for polar bears and other arctic resources escalate, managers must know the sizes and distributions of the polar bear populations. Resource managers also need reliable estimates of breeding rates, reproductive intervals, litter sizes, and survival of young and adults.Our objectives for this research were 1) to determine the seasonal and annual movements of polar bears in the Beaufort Sea, 2) to define the boundaries of the population(s) using this region, 3) to determine the size and status of the Beaufort Sea polar bear population, and 4) to establish reproduction and survival rates (Amstrup 2000).

  13. The End of Days -- Chandra Catches X-ray Glow From Supernova

    Science.gov (United States)

    1999-12-01

    Through a combination of serendipity and skill, scientists have used NASA's Chandra X-ray Observatory to capture a rare glimpse of X-radiation from the early phases of a supernova, one of the most violent events in nature. Although more than a thousand supernovas have been observed by optical astronomers, the early X-ray glow from the explosions has been detected in less than a dozen cases. The Chandra observations were made under the direction of a team of scientists from the Massachusetts Institute of Technology (MIT) in Cambridge, led by Walter Lewin and his graduate student, Derek Fox. When combined with simultaneous observations by radio and optical telescopes, the X-ray observations tell about the thickness of the shell that was blown off, its density, its speed, and how much material was shed by the star before it exploded. Chandra observed an X-ray glow from SN1999em with the total power of 50,000 suns. Ten days later it observed the supernova for another nine hours, and found that the X rays had faded to half their previous intensity. The optical luminosity, which had the brightness of 200 million suns, had faded somewhat less. No radio emission was detected at any time. With this information, the MIT group and their colleagues are already piecing together a picture of the catastrophic explosion. Observations by optical astronomers showed that SN1999em was a Type II supernova produced by the collapse of the core of a star ten or more times as massive as the Sun. The intense heat generated in the collapse produces a cataclysmic rebound that sends high speed debris flying outward at speeds in excess of 20 million miles per hour. The debris crashes into matter shed by the former star before the explosion. This awesome collision generates shock waves that heat expanding debris to three million degrees. The X-ray glow from this hot gas was detected by Chandra and gives astrophysicists a better understanding of the dynamics of the explosion, as well as the

  14. Proteomic analysis of human metaphase chromosomes reveals Topoisomerase II alpha as an Aurora B substrate

    DEFF Research Database (Denmark)

    Morrison, Ciaran; Henzing, Alexander J; Jensen, Ole Nørregaard

    2002-01-01

    The essential Aurora B kinase is a chromosomal passenger protein that is required for mitotic chromosome alignment and segregation. Aurora B function is dependent on the chromosome passenger, INCENP. INCENP, in turn, requires sister chromatid cohesion for its appropriate behaviour. Relatively few...... composition of the extracted chromosome fraction. Cloning, fluorescent tagging and expression in HeLa cells of the putative GTP-binding protein NGB/CRFG demonstrated it to be a novel mitotic chromosome protein, with a perichromosomal localisation. Identi fication of the protein bands corresponding to those...

  15. ANCHR mediates Aurora-B-dependent abscission checkpoint control through retention of VPS4

    DEFF Research Database (Denmark)

    Thoresen, Sigrid B; Campsteijn, Coen; Vietri, Marina

    2014-01-01

    of the ESCRT machinery, the ATPase VPS4. In concert with CHMP4C, ANCHR associates with VPS4 at the midbody ring following DNA segregation defects to control abscission timing and prevent multinucleation in an Aurora-B-dependent manner. This association prevents VPS4 relocalization to the abscission zone...... and is relieved following inactivation of Aurora B to allow abscission. We propose that the abscission checkpoint is mediated by ANCHR and CHMP4C through retention of VPS4 at the midbody ring....

  16. Energies of precipitating electrons during pulsating aurora events derived from ionosonde observations

    International Nuclear Information System (INIS)

    MacDougall, J.W.; Hofstee, J.; Koehler, J.A.

    1981-01-01

    The time-history of particle energies and fluxes associated with pulsating auroras in the morning sector is derived from ionosonde measurements. All the pulsating auroras studied showed a similar history with the pulsations occurring during a time interval of the order of an hour during which the average auroral Maxwellian characteristic energy stays relatively constant but the energy flux decreases progressively during the event. A possible explanation for this behaviour in terms of an injection of particles into a magnetospheric 'bottle' near the midnight meridian and the progressive precipitation out of the bottle during the pulsating event is suggested. (auth)

  17. Thermoluminescence glow-curve deconvolution functions for mixed order of kinetics and continuous trap distribution

    International Nuclear Information System (INIS)

    Kitis, G.; Gomez-Ros, J.M.

    2000-01-01

    New glow-curve deconvolution functions are proposed for mixed order of kinetics and for continuous-trap distribution. The only free parameters of the presented glow-curve deconvolution functions are the maximum peak intensity (I m ) and the maximum peak temperature (T m ), which can be estimated experimentally together with the activation energy (E). The other free parameter is the activation energy range (ΔE) for the case of the continuous-trap distribution or a constant α for the case of mixed-order kinetics

  18. An experimental study on discharge mechanism of pulsed atmospheric pressure glow discharges

    International Nuclear Information System (INIS)

    Huang Xiaojiang; Bao Yun; Sun Liqun; Zhang Jing; Shi, J. J.

    2011-01-01

    The discharge mechanism of pulsed atmospheric pressure glow discharges excited by the unipolar positive voltage pulses between two parallel plate electrodes with or without one dielectric barrier on the ground electrode in flowing helium has been characterized by nanosecond time resolved optical and electrical measurements. The uniform glow discharges can only be achieved when the voltage pulse duration is less than 1 μs with bare electrodes. With introducing a dielectric barrier on the ground electrode, a model of electrons traveling on the background ions between two discharge events is proposed to explain the discharge mechanism and characteristics in terms of discharge ignition, discharge spatial profile and discharge current amplitude.

  19. The Rose-red Glow of Star Formation

    Science.gov (United States)

    2011-03-01

    The vivid red cloud in this new image from ESO's Very Large Telescope is a region of glowing hydrogen surrounding the star cluster NGC 371. This stellar nursery lies in our neighbouring galaxy, the Small Magellanic Cloud. The object dominating this image may resemble a pool of spilled blood, but rather than being associated with death, such regions of ionised hydrogen - known as HII regions - are sites of creation with high rates of recent star birth. NGC 371 is an example of this; it is an open cluster surrounded by a nebula. The stars in open clusters all originate from the same diffuse HII region, and over time the majority of the hydrogen is used up by star formation, leaving behind a shell of hydrogen such as the one in this image, along with a cluster of hot young stars. The host galaxy to NGC 371, the Small Magellanic Cloud, is a dwarf galaxy a mere 200 000 light-years away, which makes it one of the closest galaxies to the Milky Way. In addition, the Small Magellanic Cloud contains stars at all stages of their evolution; from the highly luminous young stars found in NGC 371 to supernova remnants of dead stars. These energetic youngsters emit copious amounts of ultraviolet radiation causing surrounding gas, such as leftover hydrogen from their parent nebula, to light up with a colourful glow that extends for hundreds of light-years in every direction. The phenomenon is depicted beautifully in this image, taken using the FORS1 instrument on ESO's Very Large Telescope (VLT). Open clusters are by no means rare; there are numerous fine examples in our own Milky Way. However, NGC 371 is of particular interest due to the unexpectedly large number of variable stars it contains. These are stars that change in brightness over time. A particularly interesting type of variable star, known as slowly pulsating B stars, can also be used to study the interior of stars through asteroseismology [1], and several of these have been confirmed in this cluster. Variable stars

  20. Observation of summer daytime aurora in the noctilucent cloud layer and its link to high-energy particle precipitation during high-speed solar wind streams

    Science.gov (United States)

    Lee, Y.; Kwak, Y. S.; Kim, K. C.; Solheim, B.; Park, J.

    2015-12-01

    Aurora produced by precipitating low-energy electrons can be suppressed in summer daytime. However, the high-energy electrons (>30 keV) that are unsuppressed by sunlight are capable of penetrating deep into the mesosphere, where they can produce the odd hydrogen (HOx) and eventually lead to catalytic ozone (O3) loss. By elevating the D-region ionization level, they also play the important role of facilitating the production of polar mesospheric summer echoes (PMSE) as a precursor of polar mesospheric clouds (PMC). In the present study, it was discovered that high-energy electrons induce supersonic luminous phenomena, including the enhancement of O(1S) 557.7-nm emission with an intensity of up to 300 kR (horizontally integrated) and a supersonic velocity (300-1500 m s-1) as seen within a field of view that is 150-km wide, also called a supersonic burst (SB). SB-accompanied O(1S) emission enhancement is differentiated from aurora because the former occurs only in summer daytime, at a low altitude of ~80 km, and in the form of an intense localised burst. The source of the SB energy might be linked to the precipitation of high-energy electrons (>30 keV), especially as observed during high-speed solar wind streams (HSSs). In producing O(1S) emission, the secondary electron number flux of the precipitated primary electrons increases in magnitude by as much as an order of four, and a local process is required to provide the supplement. The supplementary local process may involve a supersonic velocity possibly caused by ion acceleration in a strong electric field, resulting in the inducement of electron acceleration in the field.

  1. Endotoxin removal by radio frequency gas plasma (glow discharge)

    Science.gov (United States)

    Poon, Angela

    2011-12-01

    Contaminants remaining on implantable medical devices, even following sterilization, include dangerous fever-causing residues of the outer lipopolysaccharide-rich membranes of Gram-negative bacteria such as the common gut microorganism E. coli. The conventional method for endotoxin removal is by Food & Drug Administration (FDA)-recommended dry-heat depyrogenation at 250°C for at least 45 minutes, an excessively time-consuming high-temperature technique not suitable for low-melting or heat-distortable biomaterials. This investigation evaluated the mechanism by which E. coli endotoxin contamination can be eliminated from surfaces during ambient temperature single 3-minute to cumulative 15-minute exposures to radio-frequency glow discharge (RFGD)-generated residual room air plasmas activated at 0.1-0.2 torr in a 35MHz electrodeless chamber. The main analytical technique for retained pyrogenic bio-activity was the Kinetic Chromogenic Limulus Amebocyte Lysate (LAL) Assay, sufficiently sensitive to document compliance with FDA-required Endotoxin Unit (EU) titers less than 20 EU per medical device by optical detection of enzymatic color development corresponding to < 0.5 EU/ml in sterile water extracts of each device. The main analytical technique for identification of chemical compositions, amounts, and changes during sequential reference Endotoxin additions and subsequent RFGD-treatment removals from infrared (IR)-transparent germanium (Ge) prisms was Multiple Attenuated Internal Reflection (MAIR) infrared spectroscopy sensitive to even monolayer amounts of retained bio-contaminant. KimaxRTM 60 mm x 15 mm and 50mm x 15mm laboratory glass dishes and germanium internal reflection prisms were inoculated with E. coli bacterial endotoxin water suspensions at increments of 0.005, 0.05, 0.5, and 5 EU, and characterized by MAIR-IR spectroscopy of the dried residues on the Ge prisms and LAL Assay of sterile water extracts from both glass and Ge specimens. The Ge prism MAIR

  2. Aurora Flight Sciences' Perseus B Remotely Piloted Aircraft in Flight

    Science.gov (United States)

    1998-01-01

    A long, slender wing and a pusher propeller at the rear characterize the Perseus B remotely piloted research aircraft, seen here during a test flight in June 1998. Perseus B is a remotely piloted aircraft developed as a design-performance testbed under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project. Perseus is one of several flight vehicles involved in the ERAST project. A piston engine, propeller-powered aircraft, Perseus was designed and built by Aurora Flight Sciences Corporation, Manassas, Virginia. The objectives of Perseus B's ERAST flight tests have been to reach and maintain horizontal flight above altitudes of 60,000 feet and demonstrate the capability to fly missions lasting from 8 to 24 hours, depending on payload and altitude requirements. The Perseus B aircraft established an unofficial altitude record for a single-engine, propeller-driven, remotely piloted aircraft on June 27, 1998. It reached an altitude of 60,280 feet. In 1999, several modifications were made to the Perseus aircraft including engine, avionics, and flight-control-system improvements. These improvements were evaluated in a series of operational readiness and test missions at the Dryden Flight Research Center, Edwards, California. Perseus is a high-wing monoplane with a conventional tail design. Its narrow, straight, high-aspect-ratio wing is mounted atop the fuselage. The aircraft is pusher-designed with the propeller mounted in the rear. This design allows for interchangeable scientific-instrument payloads to be placed in the forward fuselage. The design also allows for unobstructed airflow to the sensors and other devices mounted in the payload compartment. The Perseus B that underwent test and development in 1999 was the third generation of the Perseus design, which began with the Perseus Proof-Of-Concept aircraft. Perseus was initially developed as part of NASA's Small High-Altitude Science Aircraft (SHASA) program, which later evolved into the ERAST

  3. Properties of the positive column of a glow discharge in flowing hydrogen

    International Nuclear Information System (INIS)

    Brunet, H.; Rocca Serra, J.; Mabru, M.

    1981-01-01

    Results of a theoretical model for predicting the effects of gas flow on the properties of the positive column in a glow discharge are presented. A cylindrical discharge at low pressure ( 2 molecules and H atoms produced by the discharge are calculated. Comparison with available experimental data is made

  4. Surface analysis by glow discharge spectrometry: cathode zone and sputtering yield

    International Nuclear Information System (INIS)

    Ohannessian, L.

    1986-01-01

    Applications of the glow discharge optical spectroscopy for surface analysis are numerous. Moreover, this method enables to get qualitative and semi-quantitative results which are already significant. However, we should improve our knowledge of the physical parameters involved in the glow discharge lamp mechanisms and learn to handle such phenomena. The problems can be divided into two categories: sputtering of the target under argon ions accelerated in the cathode dark space, and luminous emission of torn away species which reach the negative glow region. Our aim was to take stock of the present theoretical knowledge which can be applied to the specific self-maintained glow discharge plasma. Moreover, we tried to link together (often roughly) the basic discharge parameters, i.e. current intensity I, voltage of the lamp Vg, pressure of the gas p. Specially a comparison between theoretical and experimental results was established concerning the pure target sputtering yields. The contribution of the argon ions striking the cathode is estimated taking into account their energetic distribution. The role of the fast argon neutrals produced by charge exchange with the ions is important; we evaluated their energetic distribution and their contribution to sputtering. The total theoretical sputtering yield is inferred: the comparison with experimental results is presented. The role of the gas temperature is emphasized [fr

  5. Spectra of explosive glowing of heavy metal azides at initiation by high-current electron beam

    Science.gov (United States)

    Oleshko, V. I.; Lysyk, V. V.

    2016-02-01

    Glowing spectra of products resulted by heavy metal azides explosive decomposition initiated by high-current electron beam were measured and identified. Intensive emission lines related to atoms of alkali metals were observed in spectra of samples under study. These atoms enter explosives during their preparation. Emission lines of elements being part of a sample holder were also presented in spectra of explosion.

  6. Fluid model of dc glow discharge with nonlocal ionization source term

    International Nuclear Information System (INIS)

    Rafatov, I R; Bogdanov, E A; Kudryavtsev, A A

    2012-01-01

    We developed and tested a simple hybrid model for a glow discharge, which incorporates nonlocal ionization by fast electrons into the fluid framework. Calculations have been performed for an argon gas. Comparison with the experimental data as well as with the hybrid (particle) and fluid modelling results demonstated good applicability of the proposed model.

  7. Simulation Study of an Extended Density DC Glow Toroidal Plasma Source

    International Nuclear Information System (INIS)

    Granda-Gutierrez, E. E.; Piedad-Beneitez, A. de la; Lopez-Callejas, R.; Godoy-Cabrera, O. G.; Benitez-Read, J. S.; Pacheco-Sotelo, J. O.; Pena-Eguiluz, R.; Mercado-Cabrera, A.; Valencia A, R.; Barocio, S. R.

    2006-01-01

    Conventional wisdom assigns the DC glow discharge regime to plasma currents below ∼500 mA values, beyond which the discharge falls into the anomalous glow and the turbulent arc regimes. However, we have found evidence that, during toroidal discharges, this barrier can be ostensibly extended up to 800 mA. Thus, a computer simulation has been applied to the evolution of the main electrical characteristics of such a glow discharge plasma in a toroidal vessel in order to design and construct a respective voltage/current controlled source. This should be able to generate a DC plasma in the glow regime with which currents in the range 10-3-100 A can be experimented and 109-1010 cm-3 plasma densities can be achieved to PIII optimization purposes. The plasma is modelled as a voltage-controlled current source able to be turned on whenever the breakdown voltage is reached across the gap between the anode and the vessel wall. The simulation outcome fits well our experimental measurements showing that the plasma current obeys power laws that are dependent on the power current and other control variables such as the gas pressure

  8. 110 C thermoluminescence glow peak of quartz – A brief review

    Indian Academy of Sciences (India)

    There is no general formalism that can exactly explain and predict the behav- ..... charge build-up during irradiation and the transfer of charges from R-centres to .... Future challenges. Although a lot of work has been carried out to bring out the various facets of the 110◦C TL glow peak of quartz, the phenomena governing the ...

  9. Effect Of Pre-Heat Temperature On The Tl Glow Curve Of Fused ...

    African Journals Online (AJOL)

    Anomalous fading was observed between the two glow peaks with the deeper trap represented by peak 2, growing at the expense of the shallower peak 1. The dose response curve of the glass was some how linear within the dose range considered. It can be concluded from this study, that with a judicious choice of ...

  10. Does exclusion of protest zeros and warm-glow bidders cause selection bias in Contingent Valuation?

    DEFF Research Database (Denmark)

    Grammatikopoulou, Ioanna; Olsen, Søren Bøye; Pouta, Eija

    A great issue of concern in valuation studies is whether respondents provide trustworthy and reliable answers conditional on the perceived information. Respondent may report either a higher than the true Willingness-To-Pay (WTP) due to warm glow or embedding effects or zero WTP which is lower than...

  11. Plasma Processing with a One Atmosphere Uniform Glow Discharge Plasma (OAUGDP)

    Science.gov (United States)

    Reece Roth, J.

    2000-10-01

    The vast majority of all industrial plasma processing is conducted with glow discharges at pressures below 10 torr. This has limited applications to high value workpieces as a result of the large capital cost of vacuum systems and the production constraints of batch processing. It has long been recognized that glow discharges would play a much larger industrial role if they could be operated at one atmosphere. The One Atmosphere Uniform Glow Discharge Plasma (OAUGDP) has been developed at the University of Tennessee Plasma Sciences Laboratory. The OAUGDP is non-thermal RF plasma with the time-resolved characteristics of a classical low pressure DC normal glow discharge. An interdisciplinary team was formed to conduct exploratory investigations of the physics and applications of the OAUGDP. This team includes collaborators from the UTK Textiles and Nonwovens Development Center (TANDEC) and the Departments of Electrical and Computer Engineering, Microbiology, Food Science and Technology, and Mechanical and Aerospace Engineering and Engineering Science. Exploratory tests were conducted on a variety of potential plasma processing and other applications. These include the use of OAUGDP to sterilize medical and dental equipment and air filters; diesel soot removal; plasma aerodynamic effects; electrohydrodynamic (EDH) flow control of the neutral working gas; increasing the surface energy of materials; increasing the wettability and wickability of fabrics; and plasma deposition and directional etching. A general overview of these topics will be presented.

  12. SkyGlowNet: an Internet-Enabled Light at Night Monitoring System

    Science.gov (United States)

    Craine, Erin M.; Craine, Eric R.; Craine, Brian L.; Crawford, David L.

    2013-05-01

    The "Sky Glow Network" (SkyGlowNet) is an internet connected depository of photometric light at night (LAN) data that are collected automatically by static, internet-enabled Sky Brightness Meters (iSBMs). The data are collected nightly at high temporal frequency and can be used to monitor extended areas of sky brightness on hourly, nightly, monthly, seasonal, and annual cycles over long periods of time. The photometry can be used for scientific and community planning purposes, as well as a powerful tool for science, technology, engineering, and mathematics (STEM) educational outreach programs. The effective and efficient use of light in modern society has become an important and contentious issue that urgently requires better technical and societal understanding. It is important to us as astronomers, and will become increasingly relevant as dark sky areas shrink as a result of poorly implemented lighting. We outline the structure of SkyGlowNet, describe the iSBM unit, and discuss how to interact with the SkyGlowNet website. We discuss how these data can help us preserve observing sites in the future.

  13. Cancer Cell Resistance to Aurora Kinase Inhibitors: Identification of Novel Targets for Cancer Therapy

    Czech Academy of Sciences Publication Activity Database

    Hrabáková, Rita; Kollaredy, M.; Tylečková, Jiřina; Halada, Petr; Hajdúch, M.; Gadher, S. J.; Kovářová, Hana

    2013-01-01

    Roč. 12, č. 1 (2013), s. 455-469 ISSN 1535-3893 R&D Projects: GA MŠk LC07017 Institutional support: RVO:67985904 ; RVO:61388971 Keywords : Aurora kinase inhibitors * resistance * p53 * apoptosis Subject RIV: CE - Biochemistry Impact factor: 5.001, year: 2013

  14. Discovery of Salamandra atra aurorae (Trevisan, 1982 on the Altopiano di Vezzena, Trentino (Northeastern Italy

    Directory of Open Access Journals (Sweden)

    Wouter Beukema

    2008-05-01

    Full Text Available Aurora’s Alpine Salamander is a limited distributed subspecies endemic to the Altopiano di Asiago, Veneto. In the current paper the occurrence of Salamandra atra aurorae is described for the Altopiano di Vezzena, Trentino. The aim of this paper is to review the distribution as well as to comment on the conservational status of the subspecies in Trentino.

  15. Recent laser experiments on the Aurora KrF/ICF laser system

    International Nuclear Information System (INIS)

    Turner, T.P.; Jones, J.E.; Czuchlewski, S.J.; Watt, R.G.; Thomas, S.J.; Kang, M.; Tallman, C.R.; Mack, J.M.; Figueira, J.F.

    1990-01-01

    The Aurora KrF/ICF Laser Facility at Los Alamos is operational at the kilojoule-level for both laser and target experiments. We report on recent laser experiments on the system and resulting system improvements. 3 refs., 4 figs

  16. Energetic electron precipitation associated with pulsating aurora: EISCAT and Van Allen Probe observations

    Czech Academy of Sciences Publication Activity Database

    Miyoshi, Y.; Oyama, S.; Saito, S.; Kurita, S.; Fujiwara, H.; Kataoka, R.; Ebihara, Y.; Kletzing, C.; Reeves, G.; Santolík, Ondřej; Clilverd, M.; Rodger, C. J.; Turunen, E.; Tsuchiya, F.

    2015-01-01

    Roč. 120, č. 4 (2015), s. 2754-2766 ISSN 2169-9380 Institutional support: RVO:68378289 Keywords : pulsating aurora * EISCAT * Van Allen Probes * pitch angle scattering Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.318, year: 2015 http://onlinelibrary.wiley.com/doi/10.1002/2014JA020690/abstract

  17. Aurora kinase A is essential for correct chromosome segregation in mouse zygote

    Czech Academy of Sciences Publication Activity Database

    Kovaříková, V.; Burkus, J.; Rehák, P.; Brzáková, Adéla; Šolc, Petr; Baran, V.

    2016-01-01

    Roč. 24, č. 3 (2016), s. 326-337 ISSN 0967-1994 R&D Projects: GA MŠk ED2.1.00/03.0124 Institutional support: RVO:67985904 Keywords : apoptosis * aurora A * MLN8237 * mouse zygote * spindle Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.053, year: 2016

  18. GATEWAY Demonstrations: OLED Lighting in the Offices of Aurora Lighting Design, Inc.

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Naomi J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-03-31

    At the offices of Aurora Lighting Design, Inc., in Grayslake, IL, the GATEWAY program conducted its first investigation involving OLED lighting. The project experienced several challenges, but also highlighted a number of promising attributes – which indicate that with continued improvements in efficacy, longevity, size, and flexibility, OLEDs could provide a new tool for creative and effective lighting.

  19. Aurora T: a Monte Carlo code for transportation of neutral atoms in a toroidal plasma

    International Nuclear Information System (INIS)

    Bignami, A.; Chiorrini, R.

    1982-01-01

    This paper contains a short description of Aurora code. This code have been developed at Princeton with Monte Carlo method for calculating neutral gas in cylindrical plasma. In this work subroutines such one can take in account toroidal geometry are developed

  20. Preliminary Results from a Coordinated Hisaki/Chandra/XMM-Newton Study of the Jovian Aurora and Io Plasma Torus

    Science.gov (United States)

    Kraft, Ralph; Kimura, Tomoki; Elsner, Ronald; Branduardi-Raymont, Graziella; Gladstone, Randy; Badman, Sarah Victoria; Ezoe, Yuichiro; Murakami, Go; Murray, Stephen S.; Roediger, Elke; hide

    2014-01-01

    We present preliminary results from a coordinated Hisaki/Chandra/XMM-Newton observational campaign of the Jovian aurora and Io plasma torus. The data were taken over a three week period in April, 2014. Jupiter was observed continuously with Hisaki, six times with the Chandra/HRC instrument for roughly 12 hours per observation, and twice by XMM-Newton. The goal of this observational campaign was to understand how energy and matter are exchanged between the Jovian aurora, the IPT, and the Solar wind. X-ray observations provide key diagnostics on highly stripped ions and keV electrons in the Jovian magnetosphere. We use the temporal, spatial, and spectral capabilities of the three instruments to search for correlated variability between the Solar wind, the EUV-emitting plasma of the IPT and UV aurora, and the ions responsible for the X-ray aurora. Preliminary analysis suggests a strong 45 min periodicity in the EUV emission from the electron aurora. There is some evidence for complex variability of the X-ray auroras on scales of tens of minutes. There is also clear morphological changes in the X-ray aurora that do not appear to be correlated with either variations in the IPT or Solar wind.

  1. Swarm-Aurora: A web-based tool for quickly identifying multi-instrument auroral events

    Science.gov (United States)

    Chaddock, D.; Donovan, E.; Spanswick, E.; Knudsen, D. J.; Frey, H. U.; Kauristie, K.; Partamies, N.; Jackel, B. J.; Gillies, M.; Holmdahl Olsen, P. E.

    2016-12-01

    In recent years there has been a dramatic increase in ground-based auroral imaging systems. These include the continent-wide THEMIS-ASI network, and imagers operated by other programs including GO-Canada, MIRACLE, AGO, OMTI, and more. In the near future, a new Canadian program called TREx will see the deployment of new narrow-band ASIs that will provide multi-wavelength imaging across Western Canada. At the same time, there is an unprecedented fleet of international spacecraft probing geospace at low and high altitudes. We are now in the position to simultaneously observe the magnetospheric drivers of aurora, observe in situ the waves, currents, and particles associated with MI coupling, and the conjugate aurora. Whereas a decade ago, a single magnetic conjunction between one ASI and a low altitude satellite was a relatively rare event, we now have a plethora of triple conjunctions between imagers, low-altitude spacecraft, and near-equatorial magnetospheric probes. But with these riches comes a new level of complexity. It is often difficult to identify the many useful conjunctions for a specific line of inquiry from the multitude of conjunctions where the geospace conditions are often not relevant and/or the imaging is compromised by clouds, moon, or other factors. Swarm-Aurora was designed to facilitate and drive the use of Swarm in situ measurements in auroral science. The project seeks to build a bridge between the Swarm science community, Swarm data, and the complimentary auroral data and community. Swarm-Aurora (http://swarm-aurora.phys.ucalgary.ca) incorporates a web-based tool which provides access to quick-look summary data for a large array of instruments, with Swarm in situ and ground-based ASI data as the primary focus. This web interface allows researchers to quickly and efficiently browse Swarm and ASI data to identify auroral events of interest to them. This allows researchers to be able to easily and quickly identify Swarm overflights of ASIs that

  2. Ashwagandha derived withanone targets TPX2-Aurora A complex: computational and experimental evidence to its anticancer activity.

    Directory of Open Access Journals (Sweden)

    Abhinav Grover

    Full Text Available Cancer is largely marked by genetic instability. Specific inhibition of individual proteins or signalling pathways that regulate genetic stability during cell division thus hold a great potential for cancer therapy. The Aurora A kinase is a Ser/Thr kinase that plays a critical role during mitosis and cytokinesis and is found upregulated in several cancer types. It is functionally regulated by its interactions with TPX2, a candidate oncogene. Aurora A inhibitors have been proposed as anticancer drugs that work by blocking its ATP binding site. This site is common to other kinases and hence these inhibitors lack specificity for Aurora A inhibition in particular, thus advocating the need of some alternative inhibition route. Previously, we identified TPX2 as a cellular target for withanone that selectively kill cancer cells. By computational approach, we found here that withanone binds to TPX2-Aurora A complex. In experiment, withanone treatment to cancer cells indeed resulted in dissociation of TPX2-Aurora A complex and disruption of mitotic spindle apparatus proposing this as a mechanism of the anticancer activity of withanone. From docking analysis, non-formation/disruption of the active TPX2-Aurora A association complex could be discerned. Our MD simulation results suggesting the thermodynamic and structural stability of TPX2-Aurora A in complex with withanone further substantiates the binding. We report a computational rationale of the ability of naturally occurring withanone to alter the kinase signalling pathway in an ATP-independent manner and experimental evidence in which withanone cause inactivation of the TPX2-Aurora A complex. The study demonstrated that TPX2-Aurora A complex is a target of withanone, a potential natural anticancer drug.

  3. Poison control centers' role in glow product-related outbreak detection: implications for comprehensive surveillance system.

    Science.gov (United States)

    Chu, Alvin F; Marcus, Steven M; Ruck, Bruce

    2009-01-01

    The development of syndromic surveillance systems to detect bioterrorist attacks and emerging infectious diseases has become an important and challenging goal to many governmental agencies and healthcare authorities. This study utilized the sharp increase of glow product-related calls to demonstrate the utility of poison control data for early detection of potential outbreaks during the week of Halloween in 2007. A review was conducted of the electronic records of exposures reported to the New Jersey Poison Information and Education System (NJPIES) Poison Control Hotline from 2002 through 2007 with generic code number 0201027 (glow products) set by the American Association of Poison Control Centers (AAPCC). Key information such as age, gender, time of the call, exposure reason, clinical effects, and medical outcomes along with telephone number, zip code, and county location were used in the analyses to determine the extent of the outbreak. Analyses included a total of 139 glow product-related calls during the week of Halloween in 2007 with a single-day high of 59 calls on Halloween Day. More than 90% of the glow product exposures were in children 1-10 years of age. The glow product-related calls on Halloween Day increased from 14 calls in 2002 to 59 calls in 2007, a 321% increase during a six-year period. Poison control centers in the United States are equipped with a unique and uniform input data collection system -- the National Poison Data System -- that provides an important data source in the development of a comprehensive surveillance system for early outbreak detection.

  4. Aurora: Los Alamos multikilojoule angular-multiplexed KrF driver prototype for ICF

    International Nuclear Information System (INIS)

    Rosocha, L.A.; Hanlon, J.A.; McLeod, J.

    1987-01-01

    The Los Alamos National Laboratory (LANL) has participated in programs to apply high-power gas lasers to inertial confinement fusion (ICF). The bulk of this effort has been in the development of CO/sub 2/ laser systems and laser-plasma interaction experiments at a 10.6-μm wavelength. The main hardware element in this program is the Aurora KrF laser system, which is a prototype for using optical angular multiplexing and serial amplification by large electron-beam-driven KrF laser amplifiers to study KrF systems as potential fusion drivers. Aurora will serve as a test-bed for specific laser, optical, and electron-beam-pumping technology aspects of larger KrF fusion systems. The Aurora system is being built in two phases. The first-phase portion of the Aurora system contains all the main optical and laser elements from the front end to the final amplifier output. In the first phase, the front end output is replicated using aperture slicers and beam splitters to produce a 480-ns long pulse train consisting of 96 separate 5-ns pulses. This pulse train is encoded in angular separation, relayed through the amplifier chain by means of the centered optical system and the computer-controlled alignment station, and delivered to a diagnostic station which follows the main power amplifier [large aperture module (LAM)]. The second phase of the system contains the first-phase portion and the additional optical and target hardware needed to stack 48 of the 96 multiplexed and amplified beams into a single multikilojoule 5-ns pulse at the fusion target. The authors give a description of the Aurora system and discuss its present status

  5. Aurora kinase B is important for antiestrogen resistant cell growth and a potential biomarker for tamoxifen resistant breast cancer

    DEFF Research Database (Denmark)

    Larsen, Sarah L; Yde, Christina W.; Laenkholm, Anne-Vibeke

    2015-01-01

    resistant T47D breast cancer cell lines. Compared with parental cells, phosphorylation of Aurora kinase B was higher in the fulvestrant resistant T47D cells. Barasertib induced degradation of Aurora kinase B, caused mitotic errors, and induced apoptotic cell death as measured by accumulation of SubG1 cells...... and PARP cleavage in the fulvestrant resistant cells. Barasertib also exerted preferential growth inhibition of tamoxifen resistant T47D cell lines. Finally, high percentage of Aurora kinase B positive tumor cells was significantly associated with reduced disease-free and overall survival in 261 ER...

  6. Aurora kinase A as a possible marker for endocrine resistance in early estrogen receptor positive breast cancer

    DEFF Research Database (Denmark)

    Lykkesfeldt, Anne E; Iversen, Benedikte R; Jensen, Maj-Britt

    2018-01-01

    BACKGROUND: Cell culture studies have disclosed that the mitotic Aurora kinase A is causally involved in both tamoxifen and aromatase inhibitor resistant cell growth and thus may be a potential new marker for endocrine resistance in the clinical setting. MATERIAL AND METHODS: Archival tumor tissue...... in 980 tumors and semi quantitively scored into three groups; negative/weak, moderate and high. The Aurora A expression levels were compared to other clinico-pathological parameters and outcome, defined as disease-free survival (DFS) and overall survival (OS). RESULTS: High expression of Aurora...

  7. Political polarization

    OpenAIRE

    Dixit, Avinash K.; Weibull, Jörgen W.

    2007-01-01

    Failures of government policies often provoke opposite reactions from citizens; some call for a reversal of the policy, whereas others favor its continuation in stronger form. We offer an explanation of such polarization, based on a natural bimodality of preferences in political and economic contexts and consistent with Bayesian rationality.

  8. Political polarization.

    Science.gov (United States)

    Dixit, Avinash K; Weibull, Jörgen W

    2007-05-01

    Failures of government policies often provoke opposite reactions from citizens; some call for a reversal of the policy, whereas others favor its continuation in stronger form. We offer an explanation of such polarization, based on a natural bimodality of preferences in political and economic contexts and consistent with Bayesian rationality.

  9. Design and performance of large area monolithic electron guns for the Aurora KrF laser system

    International Nuclear Information System (INIS)

    Kang, M.; Rosocha, L.A.; Romero, V.O.; Van Haaften, F.W.; Brucker, J.P.

    1985-01-01

    Aurora is an inertial confinement fusion laser system using optical angular multiplexing and a chain of four cold cathode electron beam driven KrF laser amplifiers to produce 10 to 20 kJ of optical energy

  10. Identification of critical chemical features for Aurora kinase-B inhibitors using Hip-Hop, virtual screening and molecular docking

    Science.gov (United States)

    Sakkiah, Sugunadevi; Thangapandian, Sundarapandian; John, Shalini; Lee, Keun Woo

    2011-01-01

    This study was performed to find the selective chemical features for Aurora kinase-B inhibitors using the potent methods like Hip-Hop, virtual screening, homology modeling, molecular dynamics and docking. The best hypothesis, Hypo1 was validated toward a wide range of test set containing the selective inhibitors of Aurora kinase-B. Homology modeling and molecular dynamics studies were carried out to perform the molecular docking studies. The best hypothesis Hypo1 was used as a 3D query to screen the chemical databases. The screened molecules from the databases were sorted based on ADME and drug like properties. The selective hit compounds were docked and the hydrogen bond interactions with the critical amino acids present in Aurora kinase-B were compared with the chemical features present in the Hypo1. Finally, we suggest that the chemical features present in the Hypo1 are vital for a molecule to inhibit the Aurora kinase-B activity.

  11. THE RELATIONSHIP BETWEEN THE SEPTEMBER 2017 MARS GLOBAL AURORA EVENT AND CRUSTAL MAGNETIC FIELDS

    Science.gov (United States)

    Nasr, Camella-Rosa; Schneider, Nick; Connour, Kyle; Jain, Sonal; Deighan, Justin; Jakosky, Bruce; MAVEN/IUVS Team

    2018-01-01

    In September 2017, the Imaging UltraViolet Spectrograph (IUVS) on the MAVEN spacecraft observed global aurora on Mars caused by a surprisingly strong solar energetic particle event. Widespread “diffuse aurora” have previously been detected on Mars through more limited observations (Schneider et al., Science 350, (2015); DOI: 10.1126/science.aad0313), but recent observations established complete coverage of the observable portion of Mars’ nightside. The aurora was global due to Mars’s lack of a global magnetic field, which allowed energetic electrons from the Sun to directly precipitate into the atmosphere. On September 11th, IUVS detected aurora more than 25 times brighter than any prior IUVS observation, with high SNR detections of aurora at the limb and against the disk of the planet. Fainter auroral emission was seen around the nightside limb over 13 orbits spanning nearly 3 days.On September 14th, during the declining phase of the event, faint linear features and patches were detected by the spacecraft, which were higher than the noise floor, with a similar spatial distribution to “discrete aurora” patches observed on Mars by the SPICAM instrument on the Mars Express spacecraft (Bertaux et al., Nature 435, doi :10.1038/nature03603). Discrete aurora occur near areas of the crust affected by the magnetism left over from Mars’ once-strong dipole field. Emission is limited to regions of the crustal magnetic field where the field lines are likely to be open to solar wind interactions. Those regions are concentrated in Mars’ southern hemisphere centered on 180 degrees east longitude.We studied the localized emissions on 14 September to determine whether there might be a connection between the observed diffuse aurora event and discrete auroral processes. First, we investigated the localized emissions to confirm that the observed signal was consistent with expected auroral spectra. Second, their locations were projected on a map of the crustal magnetic

  12. Repeated Aurora-A siRNA Transfection Results in Effective Apoptosis of A549 Cells Compared to Single Transfection.

    Science.gov (United States)

    Wang, Zhonghua; Sun, Wenwu; Cao, Jianping; Cui, Haiyang; Ma, Zhuang

    2016-01-01

    Suppression of Aurora kinase A (Aurora-A, AURKA) by Aurora-A siRNA has been proposed for lung tumor treatment. However, protocols using single administration have shown little benefit in some types of lung tumor. Given that transfection efficiency of Aurora-A siRNA is low due to tightly packed cells in the tumor, we hypothesized that repeated administration would result in efficient cell apoptosis. We compared single vs. repeated transfection (thrice) in A549 cells by transfecting Aurora-A siRNA (siA) on the 1st or 1st, 2nd and 3rd day after cell seeding. A random sequence was used as the negative siRNA control (siC). Cells in the single transfection group received only transfection reagent without siRNAs on the 2nd and 3rd day. Two days after the third transfection, both single and repeated siA administration decreased mRNA expression of Aurora-A and cell viability compared to no administration and siC single administration. However, the decrease in these two indices with repeated transfection was more obvious than that following single administration: cell viability decreased to 72.8 ± 3.05% (p transfection and to 64.2 ± 1.99% (p transfection, compared with normal control cells, respectively. Gene expression decreased to 17 ± 16.6% (p transfection and to 43.2 ± 13.0% (p transfection. Compared to single transfection, repeated Aurora-A siRNA transfection decreased Aurora-A, which, in turn, resulted in effective apoptosis of A549 cells.

  13. Simultaneous Aurora-A/STK15 overexpression and centrosome amplification induce chromosomal instability in tumour cells with a MIN phenotype

    International Nuclear Information System (INIS)

    Lentini, Laura; Amato, Angela; Schillaci, Tiziana; Di Leonardo, Aldo

    2007-01-01

    Genetic instability is a hallmark of tumours and preneoplastic lesions. The predominant form of genome instability in human cancer is chromosome instability (CIN). CIN is characterized by chromosomal aberrations, gains or losses of whole chromosomes (aneuploidy), and it is often associated with centrosome amplification. Centrosomes control cell division by forming a bipolar mitotic spindle and play an essential role in the maintenance of chromosomal stability. However, whether centrosome amplification could directly cause aneuploidy is not fully established. Also, alterations in genes required for mitotic progression could be involved in CIN. A major candidate is represented by Aurora-A/STK15 that associates with centrosomes and is overexpressed in several types of human tumour. Centrosome amplification were induced by hydroxyurea treatment and visualized by immunofluorescence microscopy. Aurora-A/STK15 ectopic expression was achieved by retroviral infection and puromycin selection in HCT116 tumour cells. Effects of Aurora-A/STK15 depletion on centrosome status and ploidy were determined by Aurora-A/STK15 transcriptional silencing by RNA interference. Changes in the expression levels of some mitotic genes were determined by Real time RT-PCR. We investigated whether amplification of centrosomes and overexpression of Aurora-A/STK15 induce CIN using as a model system a colon carcinoma cell line (HCT116). We found that in HCT116 cells, chromosomally stable and near diploid cells harbouring a MIN phenotype, centrosome amplification induced by hydroxyurea treatment is neither maintained nor induces aneuploidy. On the contrary, ectopic overexpression of Aurora-A/STK15 induced supernumerary centrosomes and aneuploidy. Aurora-A/STK15 transcriptional silencing by RNA interference in cells ectopically overexpressing this kinase promptly decreased cell numbers with supernumerary centrosomes and aneuploidy. Our results show that centrosome amplification alone is not sufficient

  14. Structural basis of N-Myc binding by Aurora-A and its destabilization by kinase inhibitors

    Science.gov (United States)

    Richards, Mark W.; Burgess, Selena G.; Poon, Evon; Carstensen, Anne; Eilers, Martin; Chesler, Louis

    2016-01-01

    Myc family proteins promote cancer by inducing widespread changes in gene expression. Their rapid turnover by the ubiquitin–proteasome pathway is regulated through phosphorylation of Myc Box I and ubiquitination by the E3 ubiquitin ligase SCFFbxW7. However, N-Myc protein (the product of the MYCN oncogene) is stabilized in neuroblastoma by the protein kinase Aurora-A in a manner that is sensitive to certain Aurora-A–selective inhibitors. Here we identify a direct interaction between the catalytic domain of Aurora-A and a site flanking Myc Box I that also binds SCFFbxW7. We determined the crystal structure of the complex between Aurora-A and this region of N-Myc to 1.72-Å resolution. The structure indicates that the conformation of Aurora-A induced by compounds such as alisertib and CD532 is not compatible with the binding of N-Myc, explaining the activity of these compounds in neuroblastoma cells and providing a rational basis for the design of cancer therapeutics optimized for destabilization of the complex. We also propose a model for the stabilization mechanism in which binding to Aurora-A alters how N-Myc interacts with SCFFbxW7 to disfavor the generation of Lys48-linked polyubiquitin chains. PMID:27837025

  15. Transitions between corona, glow, and spark regimes of nanosecond repetitively pulsed discharges in air at atmospheric pressure

    OpenAIRE

    Pai , David ,; Lacoste , Deanna ,; Laux , C.

    2010-01-01

    International audience; In atmospheric pressure air preheated from 300 to 1000 K, the nanosecond repetitively pulsed (NRP) method has been used to generate corona, glow, and spark discharges. Experiments have been performed to determine the parameter space (applied voltage, pulse repetition frequency, ambient gas temperature, and interelectrode gap distance) of each discharge regime. In particular, the experimental conditions necessary for the glow regime of NRP discharges have been determine...

  16. Measurement and analysis for optical radiation of glow discharge plasma at atmospheric pressure

    Science.gov (United States)

    Ren, Qinglei; Lin, Qi

    2006-02-01

    The optical radiation measurement and analysis to the glow discharge plasma at atmospheric pressure have been done in the paper. The low temperature plasma due to atmospheric pressure glow discharge (APGD) in air has been produced on the planar surface of designed electrode plate. The optical radiation spectra of the plasma produced in two kinds of electrode plats with different power values loaded have been measured and sampled with the minitype grating spectrograph system. The acquired spectra data are processed averagely and analyzed. The results of analysis indicate that the optical characteristic of the APGD plasma is related to the loaded power and layout of the electrode plate. This shows that it is feasible to describe the characteristic parameters of APGD plasma qualitatively and control the strength of the APGD plasma quantitatively by the obtained relationship, which provides a convenient approach for utilizing APGD plasma effectively and also establishes some foundation to investigate APGD plasma further.

  17. Fading prediction in thermoluminescent materials using computerised glow curve deconvolution (CGCD)

    CERN Document Server

    Furetta, C; Weng, P S

    1999-01-01

    The fading of three different thermoluminescent (TL) materials, CaF sub 2 : Tm (TLD-300), manocrystalline LiF : Mg,Ti (DTG-4) and MgB sub 4 O sub 7 : Dy,Na has been studied at room temperature and at 50 deg. C of storage. The evolution as a function of the elapsed time of the whole glow curve as well as of the individual peaks has been analysed using the Computerised Glow Curve Deconvolution (CGCD) program developed at the NTHU. The analysis allows to predict the loss of the dosimetric information and to make any correction is necessary for using the TL dosimeters in practical applications. Furthermore, it is well demonstrated that using CGCD it is not necessary to anneal the peaks having a rapid fading to avoid, then, any interfering effect on the more stable peaks.

  18. Inner surface modification of a tube by magnetic glow-arc plasma source ion implantation

    International Nuclear Information System (INIS)

    Zhang Guling; Chinese Academy of Sciences, Beijing; Wang Jiuli; Feng Wenran; Chen Guangliang; Gu Weichao; Niu Erwu; Fan Songhua; Liu Chizi; Yang Size; Wu Xingfang

    2006-01-01

    A new method named the magnetic glow-arc plasma source ion implantation (MGA-PSII) is proposed for inner surface modification of tubes. In MGA-PSII, under the control of an axial magnetic field, which is generated by an electric coil around the tube sample, glow arc plasma moves spirally into the tube from its two ends. A negative voltage applied on the tube realized its inner surface implantation. Titanium nitride (TiN) films are prepared on the inner surface of a stainless steel tube in diameter 90 mm and length 600 mm. Hardness tests show that the hardness at the tube centre is up to 20 GPa. XRD, XPS and AES analyses demonstrate that good quality of TiN films can be achieved. (authors)

  19. Inner Surface Modification of a Tube by Magnetic Glow-Arc Plasma Source Ion Implantation

    Science.gov (United States)

    Zhang, Gu-Ling; Wang, Jiu-Li; Wu, Xing-Fang; Feng, Wen-Ran; Chen, Guang-Liang; Gu, Wei-Chao; Niu, Er-Wu; Fan, Song-Hua; Liu, Chi-Zi; Yang, Si-Ze

    2006-05-01

    A new method named the magnetic glow-arc plasma source ion implantation (MGA-PSII) is proposed for inner surface modification of tubes. In MGA-PSII, under the control of an axial magnetic field, which is generated by an electric coil around the tube sample, glow arc plasma moves spirally into the tube from its two ends. A negative voltage applied on the tube realized its inner surface implantation. Titanium nitride (TiN) films are prepared on the inner surface of a stainless steel tube in diameter 90 mm and length 600 mm. Hardness tests show that the hardness at the tube centre is up to 20 GPa. XRD, XPS and AES analyses demonstrate that good quality of TiN films can be achieved.

  20. Discharge characteristics of atmospheric-pressure radio-frequency glow discharges with argon/nitrogen

    International Nuclear Information System (INIS)

    Wang Huabo; Sun Wenting; Li Heping; Bao Chengyu; Gao Xing; Luo Huiying

    2006-01-01

    In this letter, atmospheric-pressure glow discharges in γ mode with argon/nitrogen as the plasma-forming gas using water-cooled, bare copper electrodes driven by radio-frequency power supply at 13.56 MHz are achieved. The preliminary studies on the discharge characteristics show that, induced by the α-γ coexisting mode or γ mode discharge of argon, argon-nitrogen mixture with any mixing ratios, even pure nitrogen, can be employed to generate the stable γ mode radio-frequency, atmospheric-pressure glow discharges and the discharge voltage rises with increasing the fraction of nitrogen in the argon-nitrogen mixture for a constant total gas flow rate

  1. Nature and mechanism of blue glow of corundum crystals; new point of view

    International Nuclear Information System (INIS)

    Bessonova, T.S.; Zabara, A.S.

    1987-01-01

    The photoluminescence and radioluminescence spectra were investigated for corrundum crystals grown by Verneil method with following thermal treatment in different conditions: 1) annealing in oxygen 8p=10 5 Pa, T=1770 K, t=5x10 5 s); 2) vacuum annealing (p=10 -3 Pa, T=2220 K, t=10 5 s); 3) annelaing in high reducing atmosphere. Two kinds of luminescence processes is shown to exist at 415-420 nm. Blue glow with δ ∼ 55 nm (band halfwidth) is due to anion vacancies while glow with δ ∼ 100 nm is caused by titanium ions of valancy 4. mechanisms of mentioned kinds of luminescence and their distinctive features presented. New model of electron transitions in Al 2 O 3 -lattice including anion vacancie for different excitation means is proposed

  2. On the possibility of using commercial software packages for thermoluminescence glow curve deconvolution analysis

    International Nuclear Information System (INIS)

    Pagonis, V.; Kitis, G.

    2002-01-01

    This paper explores the possibility of using commercial software for thermoluminescence glow curve deconvolution (GCD) analysis. The program PEAKFIT has been used to perform GCD analysis of complex glow curves of quartz and dosimetric materials. First-order TL peaks were represented successfully using the Weibull distribution function. Second-order and general-order TL peaks were represented accurately by using the Logistic asymmetric functions with varying symmetry parameters. Analytical expressions were derived for determining the energy E from the parameters of the Logistic asymmetric functions. The accuracy of these analytical expressions for E was tested for a wide variety of kinetic parameters and was found to be comparable to the commonly used expressions in the TL literature. The effectiveness of fit the analytical functions used here was tested using the figure of merit and was found to be comparable to the accuracy of recently published GCD expressions for first- and general-order kinetics. (author)

  3. Isotope effects on desorption kinetics of hydrogen isotopes implanted into stainless steel by glow discharge

    International Nuclear Information System (INIS)

    Matsuyama, M.; Kondo, M.; Noda, N.; Tanaka, M.; Nishimura, K.

    2015-01-01

    In a fusion device the control of fuel particles implies to know the desorption rate of hydrogen isotopes by the plasma-facing materials. In this paper desorption kinetics of hydrogen isotopes implanted into type 316L stainless steel by glow discharge have been studied by experiment and numerical calculation. The temperature of a maximum desorption rate depends on glow discharge time and heating rate. Desorption spectra observed under various experimental conditions have been successfully reproduced by numerical simulations that are based on a diffusion-limited process. It is suggested, therefore, that desorption rate of a hydrogen isotope implanted into the stainless steel is limited by a diffusion process of hydrogen isotope atoms in bulk. Furthermore, small isotope effects were observed for the diffusion process of hydrogen isotope atoms. (authors)

  4. Aurora multikilojoule KrF laser system prototype for inertial confinement fusion

    International Nuclear Information System (INIS)

    Rosocha, L.A.; Hanlon, J.A.; Mc Leod, J.; Kang, M.; Kortegaard, B.L.; Burrows, M.D.; Bowling, P.S.

    1987-01-01

    Aurora is the Los Alamos National Laboratory short-pulse, high-power, KrF laser system. It serves as an end-to-end technology demonstration for large-scale ultraviolet laser systems of interest for short wavelength, inertial confinement fusion (ICF) investigations. The systems is a prototype for using optical angular multiplexing and serial amplification by large electron-beam-driven KrF laser amplifiers to deliver stacked, 248-nm, 5-ns duration multikilojoule laser pulses to ICF targets using an --1-km-long optical beam path. The entire Aurora KrF laser system is described and the design features of the following major system components are summarized: front-end lasers, amplifier train, multiplexer, optical relay train, demultiplexer, target irradiation apparatus, and alignment and controls systems

  5. Analgesic and CNS Depressant Activities of Sea Anemone Heteractis aurora Nematocyst Toxin.

    Science.gov (United States)

    Thangaraj, Sengapillai; Bragadeeswaran, Subramanian; Srikumaran, Natarajah; Suguna, Anbukkarasu

    2016-01-01

    Marine organisms are the excellent sources for biologically active compounds. Cnidarian venoms are potentially valuable materials used for biomedical research and drug development. The present work was carried out to analyse haemolytic, analgesic and CNS depressant activity of sea anemone Heteractis aurora. In haemolytic assay, among the five different RBC blood cells, the chicken blood exhibited maximum hemolytic activity of 64 Hemolytic Unit (HU). The maximum Analgesic Ratio (AR) of 5 recorded at 15 and 30 min interval and minimum was recorded after 45, 60 and 120 min time intervals. In jumping response activity, the maximum of 5 AR recorded at 15, 30 & 45 min and minimum was recorded at 90 & 120 min time intervals. The maximum decrease of depressant activity of 45.07% was determined in CNS depressant activity. Anti-inflammatory activity showed significant inhibition by crude extract of Heteractis aurora.

  6. Time sequence analysis of flickering auroras. I - Application of Fourier analysis. [in atmosphere

    Science.gov (United States)

    Berkey, F. T.; Silevitch, M. B.; Parsons, N. R.

    1980-01-01

    Using a technique that enables one to digitize the brightness of auroral displays from individual fields of a video signal, we have analyzed the frequency content of flickering aurora. Through the application of Fourier analysis to our data, we have found that flickering aurora contains a wide range of enhanced frequencies, although the dominant frequency enhancement generally occurs in the range 6-12 Hz. Each incidence of flickering that we observed was associated with increased radio wave absorption. Furthermore, we have found that flickering occurs in bright auroral surges, the occurrence of which is not limited to the 'breakup' phase of auroral substorms. Our results are interpreted in terms of a recently proposed theory of fluctuating double layers that accounts for a number of the observational features.

  7. Did Aboriginal Australians record a simultaneous eclipse and aurora in their oral traditions?

    Science.gov (United States)

    Fuller, Robert S.; Hamacher, Duane W.

    2017-12-01

    We investigate an Australian Aboriginal cultural story that seems to describe an extraordinary series of astronomical events occurring at the same time. We hypothesise that this was a witnessed natural event and explore natural phenomena that could account for the description. We select a thunderstorm, total solar eclipse, and strong Aurora Australis as the most likely candidates, then conclude a plausible date of 764 CE. We evaluate the different factors that would determine whether all these events could have been visible, include meteorological data, alternative total solar eclipse dates, solar activity cycles, aurorae appearances, and sky brightness during total solar eclipses. We conduct this study as a test-case for rigorously and systematically examining descriptions of rare natural phenomena in oral traditions, highlighting the difficulties and challenges with interpreting this type of hypothesis.

  8. Computer control system of the superconducting SR-light source ''Aurora''

    International Nuclear Information System (INIS)

    Yamada, H.

    1989-01-01

    The Aurora is a compact SR-light system optimized for x-ray lithography. The system includes a superconducting electron storage ring, a 150-MeV race track microtron as an injector, and light beamlines. The SR-ring features a single magnet body, in which the 650-MeV electron beam orbits a true circular trajectory of 1 m diameter. The computer control system developed for Aurora has a three-level hierarchical architecture. The top level is the Central Intelligence System, and the second an Autonomic Control System (ACS). The bottom is an assembly of distributed local controllers linked to the ACS level through optical fibers. This system provides fully automatic and remote operation, and a powerful machine study capability through the associated man--machine console and the interpretive operation language

  9. Transitions between corona, glow, and spark regimes of nanosecond repetitively pulsed discharges in air at atmospheric pressure

    Science.gov (United States)

    Pai, David Z.; Lacoste, Deanna A.; Laux, Christophe O.

    2010-05-01

    In atmospheric pressure air preheated from 300 to 1000 K, the nanosecond repetitively pulsed (NRP) method has been used to generate corona, glow, and spark discharges. Experiments have been performed to determine the parameter space (applied voltage, pulse repetition frequency, ambient gas temperature, and interelectrode gap distance) of each discharge regime. In particular, the experimental conditions necessary for the glow regime of NRP discharges have been determined, with the notable result that there exists a minimum and maximum gap distance for its existence at a given ambient gas temperature. The minimum gap distance increases with decreasing gas temperature, whereas the maximum does not vary appreciably. To explain the experimental results, an analytical model is developed to explain the corona-to-glow (C-G) and glow-to-spark (G-S) transitions. The C-G transition is analyzed in terms of the avalanche-to-streamer transition and the breakdown field during the conduction phase following the establishment of a conducting channel across the discharge gap. The G-S transition is determined by the thermal ionization instability, and we show analytically that this transition occurs at a certain reduced electric field for the NRP discharges studied here. This model shows that the electrode geometry plays an important role in the existence of the NRP glow regime at a given gas temperature. We derive a criterion for the existence of the NRP glow regime as a function of the ambient gas temperature, pulse repetition frequency, electrode radius of curvature, and interelectrode gap distance.

  10. Hardening of alloys in glow discharge with the use of pulsed electric current

    International Nuclear Information System (INIS)

    Shipko, M.N.; Pomel'nikova, A.S.; Solunin, A.M.; Solunin, M.A.

    2002-01-01

    The effect of ex/ternal pulsed electric field on the thickness of a hardened surface layer of a Nd-Fe-B system alloy during chemical heat treatment in a glow discharge is studied. The relationship is established between the hardened layer thickness and the frequency of external electric field which is verified by derived equations for the relation between electron energy and pulsed electric field frequency [ru

  11. Aligned Carbon Nano tubes Array by DC Glow Plasma Etching for Super capacitor

    International Nuclear Information System (INIS)

    Luo, Y.; Li, X.; Gong, Z.; Sheng, Z.; Peng, X.; Mou, Q.; He, M.; Li, X.; Chen, H.; Luo, Y.; Li, X.; Li, X.

    2013-01-01

    To open the end of carbon nano tubes and make these ends connect with functional carboxyl group, aligned carbon nano tubes (CNTs) arrays was etched by DC glow oxygen-argon plasma. With these open-ended carbon nano tubes array as electrode materials to build super capacitor, we found that the capacity (32.2 F/g) increased significantly than that of pure carbon nano tubes (6.7 F/g)

  12. Cathode fall parameters of a self-sustained normal glow discharge in atmospheric-pressure helium

    International Nuclear Information System (INIS)

    Arkhipenko, V.I.; Zgirovskii, S.M.; Kirillov, A.A.; Simonchik, L.V.

    2002-01-01

    Results from comprehensive studies of a high-current self-sustained glow discharge in atmospheric-pressure helium are presented. The main parameters of the cathode fall, namely, the electric field profile, cathode fall thickness, current density, gas temperature, and heat flux to the cathode are determined. The results obtained are discussed using one-dimensional models of the cathode fall with allowance for volumetric heat release

  13. Status of the Aurora laser system: Angular-multiplexed multikilojoule krypton fluoride prototype for inertial fusion

    International Nuclear Information System (INIS)

    Rosocha, L.A.; Goldstone, P.D.; Kristal, R.

    1986-01-01

    In this presentation, the authors report on the present status of the Aurora system including: The operation of the final stage 1-X 1-m laser at the 10-kJ level; the generation of 5-ns pulses by the front end; integration of the front end, multiplexer, amplifiers, and the extraction of long-pulse energy from the amplifier chain. Progress on the design and construction of the demultiplexer are also reported

  14. Bora and Aurora-A continue to activate Plk1 in mitosis

    Czech Academy of Sciences Publication Activity Database

    Bruinsma, W.; Macůrek, Libor; Freire, R.; Lindqvist, A.; Medema, R.H.

    2014-01-01

    Roč. 127, č. 4 (2014), s. 801-811 ISSN 0021-9533 R&D Projects: GA ČR GA13-18392S Grant - others:Ministerio de Economía y Competitividad(ES) SAF2010-22357; CONSOLIDER-Ingenio(NL) CDS2007-0015 Keywords : Aurora-A * Bora * Mitosis * Plk1 Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.432, year: 2014

  15. Pulsating aurora and cosmic noise absorption associated with growth-phase arcs

    Directory of Open Access Journals (Sweden)

    D. McKay

    2018-01-01

    Full Text Available The initial stage of a magnetospheric substorm is the growth phase, which typically lasts 1–2 h. During the growth phase, an equatorward moving, east–west extended, optical auroral arc is observed. This is called a growth-phase arc. This work aims to characterize the optical emission and riometer absorption signatures associated with growth-phase arcs of isolated substorms. This is done using simultaneous all-sky camera and imaging riometer observations. The optical and riometric observations allow determination of the location of the precipitation within growth-phase arcs of low- (< 10  keV and high- (>  10 keV energy electrons, respectively. The observations indicate that growth-phase arcs have the following characteristics: 1. The peak of the cosmic noise absorption (CNA arc is equatorward of the optical emission arc. This CNA is contained within the region of diffuse aurora on the equatorward side.2. Optical pulsating aurora are seen in the border region between the diffuse emission region on the equatorward side and the bright growth-phase arc on the poleward side. CNA is detected in the same region. 3. There is no evidence of pulsations in the CNA. 4. Once the equatorward drift starts, it proceeds at constant speed, with uniform separation between the growth-phase arc and CNA of 40 ± 10 km. Optical pulsating aurora are known to be prominent in the post-onset phase of a substorm. The fact that pulsations are also seen in a fairly localized region during the growth phase shows that the substorm expansion-phase dynamics are not required to closely precede the pulsating aurora.

  16. GATEWAY Report Brief: OLED Lighting in the Offices of Aurora Lighting Design, Inc.

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2016-05-31

    Summary of a GATEWAY report evaluation at the offices of Aurora Lighting Design, Inc., in Grayslake, IL, where the GATEWAY program conducted its first investigation involving OLED lighting. The project experienced several challenges, but also highlighted a number of promising attributes – which indicate that with continued improvements in efficacy, longevity, size, and flexibility, OLEDs could provide a new tool for creative and effective lighting.

  17. The impact of molecular emission in compositional depth profiling using Glow Discharge-Optical Emission Spectroscopy

    International Nuclear Information System (INIS)

    Bengtson, Arne

    2008-01-01

    The scope of this paper is to investigate and discuss how molecular emission can affect elemental analysis in glow discharge optical emission (GD-OES), particularly in compositional depth profiling (CDP) applications. Older work on molecular emission in glow discharges is briefly reviewed, and the nature of molecular emission spectra described. Work on the influence of hydrogen in the plasma, in particular elevated background due to a continuum spectrum, is discussed. More recent work from sputtering of polymers and other materials with a large content of light elements in a Grimm type source is reviewed, where substantial emission has been observed from several light diatomic molecules (CO, CH, OH, NH, C 2 ). It is discussed how the elevated backgrounds from such molecular emission can lead to significant analytical errors in the form of 'false' depth profile signals of several atomic analytical lines. Results from a recent investigation of molecular emission spectra from mixed gases in a Grimm type glow discharge are presented. An important observation is that dissociation and subsequent recombination processes occur, leading to formation of molecular species not present in the original plasma gas. Experimental work on depth profiling of a polymer coating and a thin silicate film, using a spectrometer equipped with channels for molecular emission lines, is presented. The results confirm that molecular emission gives rise to apparent depth profiles of elements not present in the sample. The possibilities to make adequate corrections for such molecular emission in CDP of organic coatings and very thin films are discussed

  18. Fit of second order thermoluminescence glow peaks using the logistic distribution function

    International Nuclear Information System (INIS)

    Pagonis, V.; Kitis, G.

    2001-01-01

    A new thermoluminescence glow curve deconvolution (GCD) function is introduced which accurately describes second order thermoluminescence (TL) curves. The logistic asymmetric (LA) statistical probability function is used with the function variables being the maximum peak intensity (I m ), the temperature of the maximum peak intensity (T m ) and the LA width parameter a 2 . An analytical expression is derived from which the activation energy E can be calculated as a function of T m and the LA width parameter a 2 with an accuracy of 2% or better. The accuracy of the fit was tested for E values ranging from 0.7 to 2.5 eV, for s values between 10 5 and 10 25 s -1 , and for trap occupation number n 0 /N between 1 and 10 -6 . The goodness of fit of the logistic asymmetric function is described by the Figure of Merit (FOM) which is found to be of the order of 10 -2 . Preliminary results show that the GCD described here can easily be extended to the description of general order TL glow curves by varying the asymmetry parameter of the logistic asymmetric function. It is concluded that the TL kinetic analysis of first, second and general order TL glow curves can be performed with high accuracy and speed by using commercially available statistical packages that incorporate the Weibull and logistic asymmetric functions. (author)

  19. Slow electron energy balance for hybrid models of direct-current glow discharges

    Science.gov (United States)

    Eliseev, S. I.; Bogdanov, E. A.; Kudryavtsev, A. A.

    2017-09-01

    In this paper, we present the formulation of slow electron energy balance for hybrid models of direct current (DC) glow discharge. Electrons originating from non-local ionization (secondary) contribute significantly to the energy balance of slow electrons. An approach towards calculating effective energy brought by a secondary electron to the group of slow electrons by means of Coulomb collisions is suggested. The value of effective energy shows a considerable dependence on external parameters of a discharge, such as gas pressure, type, and geometric parameters. The slow electron energy balance was implemented into a simple hybrid model that uses analytical formulation for the description of non-local ionization by fast electrons. Simulations of short (without positive column) DC glow discharge in argon are carried out for a range of gas pressures. Comparison with experimental data showed generally good agreement in terms of current-voltage characteristics, electron density, and electron temperature. Simulations also capture the trend of increasing electron density with decreasing pressure observed in the experiment. Analysis shows that for considered conditions, the product of maximum electron density ne and electron temperature Te in negative glow is independent of gas pressure and depends on the gas type, cathode material, and discharge current. Decreasing gas pressure reduces the heating rate of slow electrons during Coulomb collisions with secondary electrons, which leads to lower values of Te and, in turn, higher maximum ne.

  20. A comparison of hydrogen vs. helium glow discharge effects on fusion device first-wall conditioning

    International Nuclear Information System (INIS)

    Dylla, H.F.

    1989-09-01

    Hydrogen- and deuterium-fueled glow discharges are used for the initial conditioning of magnetic fusion device vacuum vessels following evacuation from atmospheric pressure. Hydrogenic glow discharge conditioning (GDC) significantly reduces the near-surface concentration of simple adsorbates, such as H 2 O, CO, and CH 4 , and lowers ion-induced desorption coefficients by typically three orders of magnitude. The time evolution of the residual gas production observed during hydrogen-glow discharge conditioning of the carbon first-wall structure of the TFTR device is similar to the time evolution observed during hydrogen GDC of the initial first-wall configuration in TFTR, which was primarily stainless steel. Recently, helium GDC has been investigated for several wall-conditioning tasks on a number of tokamaks including TFTR. Helium GDC shows negligible impurity removal with stainless steel walls. For impurity conditioning with carbon walls, helium GDC shows significant desorption of H 2 O, CO, and CO 2 ; however, the total desorption yield is limited to the monolayer range. In addition, helium GDC can be used to displace hydrogen isotopes from the near-surface region of carbon first-walls in order to lower hydrogenic retention and recycling. 38 refs., 6 figs

  1. Micro glow plasma for localized nanostructural modification of carbon nanotube forest

    Energy Technology Data Exchange (ETDEWEB)

    Sarwar, Mirza Saquib us; Xiao, Zhiming; Saleh, Tanveer; Nojeh, Alireza; Takahata, Kenichi [University of British Columbia, Vancouver, British Columbia V6T 1Z4 (Canada)

    2016-08-22

    This paper reports the localized selective treatment of vertically aligned carbon nanotubes, or CNT forests, for radial size modification of the nanotubes through a micro-scale glow plasma established on the material. An atmospheric-pressure DC glow plasma is shown to be stably sustained on the surface of the CNT forest in argon using micromachined tungsten electrodes with diameters down to 100 μm. Experiments reveal thinning or thickening of the nanotubes under the micro glow depending on the process conditions including discharge current and process time. These thinning and thickening effects in the treated nanotubes are measured to be up to ∼30% and ∼300% in their diameter, respectively, under the tested conditions. The elemental and Raman analyses suggest that the treated region of the CNT forest is pure carbon and maintains a degree of crystallinity. The local plasma treatment process investigated may allow modification of material characteristics in different domains for targeted regions or patterns, potentially aiding custom design of micro-electro-mechanical systems and other emerging devices enabled by the CNT forest.

  2. An Investigation of LED Street Lighting's Impact on Sky Glow

    Energy Technology Data Exchange (ETDEWEB)

    Kinzey, Bruce R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Perrin, Tess E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Miller, Naomi J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kocifaj, Miroslav [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Aube, Martin [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lamphar, Hector A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2017-04-25

    A significant amount of public attention has recently focused on perceived impacts of converting street lighting from incumbent lamp-based products to LED technology. Much of this attention pertains to the higher content of short wavelength light (commonly referred to as "blue light") of LEDs and its attendant influences on sky glow (a brightening of the night sky that can interfere with astronomical observation and may be associated with a host of other issues). The complexity of this topic leads to common misunderstandings and misperceptions among the public, and for this reason the U.S. Department of Energy Solid-State Lighting Program embarked on a study of sky glow using a well-established astronomical model to investigate some of the primary factors influencing sky glow. This report details the results of the investigation and attempts to present those results in terms accessible to the general lighting community. The report also strives to put the results into a larger context, and help educate interested readers on various topics relevant to the issues being discussed.

  3. Phosphorylation of CPAP by Aurora-A Maintains Spindle Pole Integrity during Mitosis.

    Science.gov (United States)

    Chou, En-Ju; Hung, Liang-Yi; Tang, Chieh-Ju C; Hsu, Wen-Bin; Wu, Hsin-Yi; Liao, Pao-Chi; Tang, Tang K

    2016-03-29

    CPAP is required for centriole elongation during S/G2 phase, but the role of CPAP in mitosis is incompletely understood. Here, we show that CPAP maintains spindle pole integrity through its phosphorylation by Aurora-A during mitosis. Depletion of CPAP induced a prolonged delay in mitosis, pericentriolar material (PCM) dispersion, and multiple mitotic abnormalities. Further studies demonstrated that CPAP directly interacts with and is phosphorylated by Aurora-A at serine 467 during mitosis. Interestingly, the dispersal of the PCM was effectively rescued by ectopic expression of wild-type CPAP or a phospho-mimic CPAP-S467D mutant, but not a non-phosphorylated CPAP-S467A mutant. Finally, we found that CPAP-S467D has a low affinity for microtubule binding but a high affinity for PCM proteins. Together, our results support a model wherein CPAP is required for proper mitotic progression, and phosphorylation of CPAP by Aurora-A is essential for maintaining spindle pole integrity. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  4. A compact SR light source for x-ray lithography 'AURORA'

    International Nuclear Information System (INIS)

    Toba, Y.

    1990-01-01

    A compact synchrotron radiation (SR) light source called AURORA has been developed for industrial use. It is specially designed for X-ray lithography. AURORA consists of a storage ring, injector microtron and SR light beam lines. The storage ring is a superconducting single magnet machine, designed to accelerate a 150 MeV electron beam to 650 MeV and to store as high as 300 mA current. The injector is a racetrack microtron (RTM) producing a pulsed 150 MeV beam. As many as 16 SR light beam channels are available for AURORA. Prototypes of the storage ring and RTM are constructed, and beam commissioning is performed. A hundred and fifty MeV electron beam of a pulsed current 10 μA from the RTM is successfully injected to the ring and accelerated to 600 MeV and 10 mA current stored with a lifetime of more than 20 hours. The half-integer method investigated is shown to work well with the injection efficiency being found to be very high. Improvement of the design is now under way. (N.K.)

  5. Injúrias mecânicas e seus efeitos em pêssegos 'Aurora-1' Effect of mechanical injuries on 'Aurora-1' peaches

    Directory of Open Access Journals (Sweden)

    Giorgia Fernanda Kasat

    2007-08-01

    Full Text Available O objetivo deste trabalho foi avaliar os efeitos das injúrias mecânicas por corte, compressão e impacto na qualidade pós-colheita de pêssegos 'Aurora-1'. Na injúria por impacto, os pêssegos foram deixados cair duas vezes de uma altura de 1,20 m. Por compressão, os frutos foram colocados sob um bloco exercendo um peso constante de 3 kg por 10 minutos. Para a injúria por corte, promoveram-se três incisões longitudinalmente. Manteve-se, ainda, um lote de pêssegos intactos, correspondente ao controle. Após esses tratamentos, os frutos foram armazenados a 10±1,5 °C e 85±2% UR por 8 dias. Avaliaram-se o teor de sólidos solúveis (SS, de acidez titulável (AT e a relação SS/AT, a perda de massa fresca, a aparência, a coloração, a firmeza e o conteúdo de carboidratos solúveis. As injúrias mecânicas promoveram marcas nos pêssegos 'Aurora-1', afetando a aparência dos mesmos, que obtiveram nota ruim a partir do sexto dia de armazenamento. Esses pêssegos, quando submetidos à injúria de impacto, apresentaram maior perda de massa fresca que os do controle, da compressão e do corte. As áreas lesionadas apresentaram-se mais escurecidas, menos amareladas, com menor cromaticidade e menos firmes que as áreas dos frutos não-submetidas às injúrias. Esse efeito deletério também foi verificado quando os frutos eram submetidos à injúria por Impacto, quando comparado com os demais tratamentos. As injúrias mecânicas promoveram um amadurecimento mais rápido dos frutos, verificado pelos maiores valores da relação SS/AT.This work aimed to evaluate the effect of mechanical injuries, impact, compression and cut on the postharvest quality of peaches cv. Aurora-1. Impact injury was obtained dropping fruit, twice, from a height of 1.20 m. Compression injury was performed with the fruit submitted to weight (3 kg for 10 minutes. Cut injury was obtained cutting fruits, three times, in the longitudinal direction. after these treatments

  6. Potential Industrial Applications of the One Atmosphere Uniform Glow Discharge Plasma (OAUGDP) Operating in Ambient Air

    Science.gov (United States)

    Reece Roth, J.

    2004-11-01

    The majority of industrial plasma processing with glow discharges has been conducted at pressures below 10 torr. This tends to limit applications to high value workpieces as a result of the high capital cost of vacuum systems and the production constraints of batch processing. It has long been recognized that glow discharge plasmas would play a much larger industrial role if they could be generated at one atmosphere. The One Atmosphere Uniform Glow Discharge Plasma (OAUGDP), developed at the University of Tennessee's Plasma Sciences Laboratory, is a non-thermal RF plasma operating on displacement currents with the time-resolved characteristics of a classical low pressure DC normal glow discharge. As a glow discharge, the OAUGDP operates with maximum electrical efficiency at the Stoletow point, where the energy input per ion-electron pair is a minimum [1, 2]. Several interdisciplinary teams have investigated potential applications of the OAUGDP. These teams included collaborators from the UTK Textiles and Nonwovens Development Center (TANDEC), and the Departments of Electrical and Computer Engineering, Microbiology, and Food Science and Technology, as well as the NASA Langley Research Center. The potential applications of the OAUGDP have all been at one atmosphere and room temperature, using air as the working gas. These applications include sterilizing medical and dental equipment; sterilizable air filters to deal with the "sick building syndrome"; removal of soot from Diesel engine exhaust; subsonic plasma aerodynamic effects, including flow re-attachment to airfoils and boundary layer modification; electrohydrodynamic (EDH) flow control of working gases; increasing the surface energy of materials; improving the adhesion of paints and electroplated layers: improving the wettability and wickability of fabrics; stripping of photoresist; and plasma deposition and directional etching of potential microelectronic relevance. [1] J. R. Roth, Industrial Plasma Engineering

  7. Characterization of the large area plane-symmetric low-pressure DC glow discharge

    Science.gov (United States)

    Avtaeva, S.; Gorokhovsky, V.; Myers, S.; Robertson, S.; Shunko, E.; Zembower, Z.

    2016-10-01

    Electron density and temperature as well as nitrogen dissociation degree in the low-pressure (10-50 mTorr) large area plane-symmetric DC glow discharge in Ar-N2 mixtures are studied by probes and spectral methods. Electron density measured by a hairpin probe is in good agreement with that derived from the intensity ratio of the N2 2nd positive system bands IC, 1 - 3/IC, 0 - 2 and from the intensity ratio of argon ions and atom lines IArII/IArI, while Langmuir probe data provides slightly higher values of electron density. Electron density in the low-pressure DC glow discharge varies with the discharge conditions in the limits of 108-1010 cm- 3. The concept of electron temperature can be used in low-pressure glow discharges with reservations. The intensity ratio of (0-0) vibrational bands of N2 1st negative and 2nd positive systems I391.4/I337.1 exhibits the electron temperature of 1.5-2.5 eV when argon fraction in the mixture is higher than nitrogen fraction and this ratio quickly increases with nitrogen fraction up to 10 eV in pure nitrogen. The electron temperature calculated from Langmuir probe I-V characteristics assuming a Maxwellian EEDF, gives Te 0.3-0.4 eV. In-depth analysis of the EEDF using the second derivative of Langmuir probe I-V characteristics shows that in a low-pressure glow discharge the EEDF is non-Maxwellian. The EEDF has two populations of electrons: the main background non-Maxwellian population of ;cold; electrons with the mean electron energy of 0.3-0.4 eV and the small Maxwellian population of ;hot; electrons with the mean electron energy of 1.0-2.5 eV. Estimations show that with electron temperature lower than 1 eV the rate of the direct electron impact ionization of N2 is low and the main mechanism of N2 ionization becomes most likely Penning and associative ionization. In this case, assumptions of the intensity ratio IN2+, 391/IN2, 337 method are violated. In the glow discharge, N2 dissociation degree reaches about 7% with the argon

  8. Desenvolvimento dos frutos de pêssego 'Aurora' e nectarina 'Sunraycer' no sul de Santa Catarina

    Directory of Open Access Journals (Sweden)

    Emilio Della Bruna

    2011-10-01

    Full Text Available O desenvolvimento do fruto de pessegueiro é resultado da diferenciação e do crescimento das paredes do ovário após a fecundação. A persistência e o crescimento do fruto na planta dependem das relações exatas entre os hormônios auxina, giberelina e citocinina que condicionam o desenvolvimento dos frutos, caracterizado por uma curva dupla sigmoide, com três estádios distintos. O presente trabalho teve por objetivo conhecer o comportamento dos frutos e das sementes do pêssego Aurora e da Nectarina Sunraycer durante todo o seu ciclo de desenvolvimento. O crescimento dos frutos e das sementes durante o ciclo foi determinado semanalmente, coletando-se 30 frutos de dez diferentes plantas em ramos previamente identificados. As sementes foram separadas do fruto para a determinação do peso fresco (PF e do peso seco (PS. O crescimento dos frutos da variedade Sunraycer dá-se de forma contínua e acelerada desde a floração até a maturação, sugerindo um curto período ou a inexistência do Estágio II de crescimento. Para a variedade Aurora, a curva de crescimento é diferenciada nos três estádios (I, II e III. O raleio dos frutos deve ser feito até o início do estádio II, para a variedade Aurora e Sunraycer. As sementes das variedades Aurora e Sunraycer atingem seu tamanho máximo no estágio I de crescimento do fruto. O aumento de peso seco na semente, para a variedade Sunraycer, é praticamente inexistente no estádio III, enquanto para a variedade Aurora ocorre o maior aumento de peso seco que vai até a maturação do fruto.

  9. Auroras and Space Weather Celebrating the International Heliophysics Year in Classroom

    Science.gov (United States)

    Craig, N.; Peticolas, L. M.; Angelopoulos, V.; Thompson, B.

    2007-05-01

    2007 Celebrates the International Heliophysics year and its outreach has a primary objective, to "demonstrate the beauty, relevance and significance of Space and Earth Science to the world." NASA's first five-satellite mission, THEMIS (Time History of Events and Macroscale Interactions during Substorms), was launched on February 17, 2007 and is to investigate a key mystery surrounding the dynamics of the auroras- when, where, and how are they triggered? When the five probes align perfectly over the North American continent- every four days - and with 20 ground stations in Northern Canada and Alaska with automated, all-sky cameras will document the auroras from Earth. To monitor the large-scale local effects of the currents in space, THEMIS Education and Outreach program has installed 10 ground magnetometers, instruments that measure Earth's magnetic field, in competitively selected rural schools around the country and receive data. The THEMIS Education and Outreach Program shares the IHY objective by bringing in this live local space weather data in the classrooms and engaging the teachers and students on authentic research in the classroom. The data are displayed on the school computer monitors as well as on the THEMIS E/PO website providing the local data to the science mission as well as schools. Teachers use the data to teach about the aurora not only in math and science, but also in Earth science, history and art. These students and their teachers are our ambassadors to rural America and share the excitement of learning and teaching with their regional teachers. We will share how authentic space science data related to Earth's magnetic field and auroras can be understood, researched, predicted and shared via the internet to any school around the globe that wished to be part of tracking solar storms. Complimenting IHY, World Space Week will take place from October 4-10th and this year. World Space week is "an international celebration of science and technology

  10. Strategic Polarization.

    Science.gov (United States)

    Kalai, Adam; Kalai, Ehud

    2001-08-01

    In joint decision making, similarly minded people may take opposite positions. Consider the example of a marriage in which one spouse gives generously to charity while the other donates nothing. Such "polarization" may misrepresent what is, in actuality, a small discrepancy in preferences. It may be that the donating spouse would like to see 10% of their combined income go to charity each year, while the apparently frugal spouse would like to see 8% donated. A simple game-theoretic analysis suggests that the spouses will end up donating 10% and 0%, respectively. By generalizing this argument to a larger class of games, we provide strategic justification for polarization in many situations such as debates, shared living accommodations, and disciplining children. In some of these examples, an arbitrarily small disagreement in preferences leads to an arbitrarily large loss in utility for all participants. Such small disagreements may also destabilize what, from game-theoretic point of view, is a very stable equilibrium. Copyright 2001 Academic Press.

  11. Corotation-driven magnetosphere-ionosphere coupling currents in Saturn’s magnetosphere and their relation to the auroras

    Directory of Open Access Journals (Sweden)

    S. W. H. Cowley

    2003-08-01

    -related currents. We thus conclude that Saturn’s ‘main oval’ auroras are not associated with corotation-enforcing currents as they are at Jupiter, but instead are most probably associated with coupling to the solar wind as at Earth. At the same time, the Voyager flow observations also suggest the presence of radially localized ‘dips’ in the plasma angular velocity associated with the moons Dione and Rhea, which are ~ 1–2 RS in radial extent in the equatorial plane. The presence of such small-scale flow features, assumed to be azimuthally extended, results in localized several-MA enhancements in the ionospheric Pedersen current, and narrow bi-polar signatures in the field-aligned currents which peak at values an order of magnitude larger than those associated with the large-scale currents. Narrow auroral rings (or partial rings ~ 0.25° co-latitude wide with intensities ~ 1 kiloRayleigh may be formed in the regions of upward field-aligned current under favourable circumstances, located at co-latitudes between ~ 17° and ~ 20° in the north, and ~ 19° and ~22° in the south.Key words. Magnetospheric physics (current systems; magnetosphere-ionosphere interactions; planetary magnetospheres

  12. Corotation-driven magnetosphere-ionosphere coupling currents in Saturn’s magnetosphere and their relation to the auroras

    Directory of Open Access Journals (Sweden)

    S. W. H. Cowley

    to expectations for corotation-related currents. We thus conclude that Saturn’s ‘main oval’ auroras are not associated with corotation-enforcing currents as they are at Jupiter, but instead are most probably associated with coupling to the solar wind as at Earth. At the same time, the Voyager flow observations also suggest the presence of radially localized ‘dips’ in the plasma angular velocity associated with the moons Dione and Rhea, which are ~ 1–2 RS in radial extent in the equatorial plane. The presence of such small-scale flow features, assumed to be azimuthally extended, results in localized several-MA enhancements in the ionospheric Pedersen current, and narrow bi-polar signatures in the field-aligned currents which peak at values an order of magnitude larger than those associated with the large-scale currents. Narrow auroral rings (or partial rings ~ 0.25° co-latitude wide with intensities ~ 1 kiloRayleigh may be formed in the regions of upward field-aligned current under favourable circumstances, located at co-latitudes between ~ 17° and ~ 20° in the north, and ~ 19° and ~22° in the south.

    Key words. Magnetospheric physics (current systems; magnetosphere-ionosphere interactions; planetary magnetospheres

  13. The relationship between auroral hiss at high altitudes over the polar caps and the substorm dynamics of aurora

    Czech Academy of Sciences Publication Activity Database

    Titova, E. E.; Yahnin, A. G.; Santolík, Ondřej; Gurnett, D. A.; Jiříček, František; Rauch, J. L.; Lefeuvre, F.; Frank, L. A.; Sigwarth, J. B.; Mogilevsky, M. M.

    2005-01-01

    Roč. 23, - (2005), s. 2117-2128 ISSN 0992-7689 R&D Projects: GA AV ČR IAA3042201; GA ČR GA205/03/0953; GA MŠk ME 650; GA ČR GA202/03/0832; GA MŠk 1P05ME811 Grant - others:ESA PECS(XE) 98025; INTAS(RU) 03-51-4132; NATO(XE) PST.GLG980041; NASA (US) NAG5-7943 Institutional research plan: CEZ:AV0Z30420517 Keywords : Magnetospheric physics (Auroral phenomena, Plasma waves and instabilities, Storms and substorms) Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.450, year: 2005

  14. The real-time state of the aurora -- a research to operations need with a citizen science solution?

    Science.gov (United States)

    Heavner, M.; MacDonald, E.; Case, N.; McCloat, S.

    2015-12-01

    A prototype citizen science application called Aurorasaurus has been developed and launched in 2014. The goal of this platform is crowdsourcing observations of the aurora in real-time in order to assess global visibility of the aurora for the public. Users can submit observations, verify relevant social media observations, learn about the aurora, and receive location-based alerts based on verified reports, all in near real-time. The size and distribution of the citizen scientist community around the world has tremendous potential both for documenting the visible manifestations of global space weather impacts as well as providing quality control on the reported sightings. Information with high spatial and temporal resolution of the largest, most dynamic and mysterious space weather events is made possible by this solution, and this data can be integrated with other ground and space based measures of auroral activity. We will present initial results during the large geomagnetic events of 2015 and comparison to other measures of auroral activity. Our findings indicate the prototype application can be a valuable tool for real-time aurora knowledge and should be included in discussions of real-time aurora nowcasting needs. We will discuss those needs and assess the feasibility of available systems for meeting them.

  15. Electron Energy and Neutral Gas Temperature in a Glow Discharge(Supported by NASA Langley Research Center.)

    Science.gov (United States)

    Popović, S.; Vušković, L.

    1997-10-01

    We investigated nonlinear and dispersion effects of strong acoustic waves in weakly ionized gas generated by glow discharge. Direct current glow discharge between two hollow cylindrical electrodes in flowing gas is a convenient arrangement for this kind of study. One of the critical parameters is the ratio of electron mean energy and neutral gas temperature, both associated with characteristic wavespeed in ionized and neutral gas. Models usually assume this parameter to be equal to infinity (``cold ions") and the effects of finite gas kinetic temperature are not included. We evaluated the axial and radial distributions of electron mean energy and gas temperature in negative glow and positive column of glow discharge in flowing Argon and Nitrogen in the pressure range of 1 to 100 Torr. These two gases are chosen because of their substantially different ionization mechanisms. The difference in discharge penetration depth into the hollow cathode, extent of the negative glow, high energy electron relaxation depth, and axial neutral transport in the two gases are obtained. Results of gas kinetic temperature are compared with reported experiments and calculations in Argon(M. Sato and S. Arima, J. Phys. D: Appl. Phys. 23), 1302 (1990). and Nitrogen.(H. Brunet and J. Rocca-Serra, J. Appl. Phys. 57), 1574 (1985).

  16. R. B. Cunninghame Graham’s “Aurora La Cujiñi” (1898 : An Exploration / Aurora La Cujiñi” (1898 de R. B. Cunninghame Graham - Una indagación

    Directory of Open Access Journals (Sweden)

    John C. Mc Intyre

    2011-06-01

    Full Text Available Abstract: In Aurora La Cujiñi-A realistic sketch in Seville, published by the Scottish writer R. B. Cunninghame Graham in 1898, the frontispiece showed the sepia image of a female flamenco dancer. What might ‘La Cujiñi’ mean? Charles Davillier and Gustave Doré in 1862-63 note the existence of a Sevillan dancer with this name. In 2011 the present writer was gifted an old lithograph, in colour, published in Seville ‘c. 1850’ and entitled ‘Aurora La Cujiñí’ - with ñ and í. The two images are supplied. ‘Aurora La Cujiñi’ really existed. Graham’s sketch has five phases: Seville; the bullfight; the crowd’s return to town; a low-quality flamenco show; and the highly stirring performance by an initially anonymous female dancer - the dead Aurora brought back to life. Graham emphasises the Seville blend of blood and sensuality in a realist style also capable of mockery and criticism. Graham’s writing includes a good variety of well-controlled Spanish vocabulary, his empathy with horses and a deep nostalgia for times past. W. H. Hudson, writer and friend of Graham, in 1894 recommended that Graham should read the Argentine sketches published by Alfred Ébélot in 1890. In Aurora La Cujiñi Graham in 1898 is beginning to show mastery of the literary sketch. Question: Might Lorca have read Aurora La Cujiñi before drafting “Teoría y juego del duende”? Resumen: En Aurora La Cujiñi-A realistic sketch in Seville (1898 del escritor escocés R. B. Cunninghame Graham, el frontispicio llevaba la imagen en sepia de una bailadora de flamenco. ¿Qué podría significar ‘La Cujiñi’? Charles Davillier y Gustave Doré en 1862-1863 apuntan la existencia de una bailaora sevillana con este nombre. En 2011 al que esto escribe le regalaron una litografía antigua, en color, publicada en Sevilla ‘hacia 1850’ e intitulada ‘Aurora la Cujiñí’ - con ñ y con í. Se incluyen las dos imágenes. ‘Aurora La Cujiñi’ realmente

  17. Precessing deuteron polarization

    International Nuclear Information System (INIS)

    Sitnik, I.M.; Volkov, V.I.; Kirillov, D.A.; Piskunov, N.M.; Plis, Yu.A.

    2002-01-01

    The feasibility of the acceleration in the Nuclotron of deuterons polarized in the horizontal plane is considered. This horizontal polarization is named precessing polarization. The effects of the main magnetic field and synchrotron oscillations are included. The precessing polarization is supposed to be used in studying the polarization parameters of the elastic dp back-scattering and other experiments

  18. Boltzmann statistical consideration on the excitation mechanism of iron atomic lines emitted from glow discharge plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Lei; Kashiwakura, Shunsuke; Wagatsuma, Kazuaki, E-mail: wagatuma@imr.tohoku.ac.jp

    2011-11-15

    A Boltzmann plot for many iron atomic lines having excitation energies of 3.3-6.9 eV was investigated in glow discharge plasmas when argon or neon was employed as the plasma gas. The plot did not show a linear relationship over a wide range of the excitation energy, but showed that the emission lines having higher excitation energies largely deviated from a normal Boltzmann distribution whereas those having low excitation energies (3.3-4.3 eV) well followed it. This result would be derived from an overpopulation among the corresponding energy levels. A probable reason for this is that excitations for the high-lying excited levels would be caused predominantly through a Penning-type collision with the metastable atom of argon or neon, followed by recombination with an electron and then stepwise de-excitations which can populate the excited energy levels just below the ionization limit of iron atom. The non-thermal excitation occurred more actively in the argon plasma rather than the neon plasma, because of a difference in the number density between the argon and the neon metastables. The Boltzmann plots yields important information on the reason why lots of Fe I lines assigned to high-lying excited levels can be emitted from glow discharge plasmas. - Highlights: Black-Right-Pointing-Pointer This paper shows the excitation mechanism of Fe I lines from a glow discharge plasma. Black-Right-Pointing-Pointer A Boltzmann distribution is studied among iron lines of various excitation levels. Black-Right-Pointing-Pointer We find an overpopulation of the high-lying energy levels from the normal distribution. Black-Right-Pointing-Pointer It is caused through Penning-type collision of iron atom with argon metastable atom.

  19. Boltzmann statistical consideration on the excitation mechanism of iron atomic lines emitted from glow discharge plasmas

    International Nuclear Information System (INIS)

    Zhang Lei; Kashiwakura, Shunsuke; Wagatsuma, Kazuaki

    2011-01-01

    A Boltzmann plot for many iron atomic lines having excitation energies of 3.3–6.9 eV was investigated in glow discharge plasmas when argon or neon was employed as the plasma gas. The plot did not show a linear relationship over a wide range of the excitation energy, but showed that the emission lines having higher excitation energies largely deviated from a normal Boltzmann distribution whereas those having low excitation energies (3.3–4.3 eV) well followed it. This result would be derived from an overpopulation among the corresponding energy levels. A probable reason for this is that excitations for the high-lying excited levels would be caused predominantly through a Penning-type collision with the metastable atom of argon or neon, followed by recombination with an electron and then stepwise de-excitations which can populate the excited energy levels just below the ionization limit of iron atom. The non-thermal excitation occurred more actively in the argon plasma rather than the neon plasma, because of a difference in the number density between the argon and the neon metastables. The Boltzmann plots yields important information on the reason why lots of Fe I lines assigned to high-lying excited levels can be emitted from glow discharge plasmas. - Highlights: ► This paper shows the excitation mechanism of Fe I lines from a glow discharge plasma. ► A Boltzmann distribution is studied among iron lines of various excitation levels. ► We find an overpopulation of the high-lying energy levels from the normal distribution. ► It is caused through Penning-type collision of iron atom with argon metastable atom.

  20. Application of Radio-Frequency Plasma Glow Discharge to Removal of Uranium Dioxide from Metal Surfaces

    International Nuclear Information System (INIS)

    El-Genk, Mohamed S.; Saber, Hamed H.

    2000-01-01

    Recent experiments have shown that radio-frequency (rf) plasma glow discharge using NF 3 gas is an effective technique for the removal of uranium oxide from metal surfaces. The results of these experiments are analyzed to explain the measured dependence of the UO 2 removal or etch rate on the NF 3 gas pressure and the absorbed power in the plasma. The NF 3 gas pressure in the experiments was varied from 10.8 to 40 Pa, and the deposited power in the plasma was varied from 25 to 210 W. The UO 2 etch rate was strongly dependent on the absorbed power and, to a lesser extent, on the NF 3 pressure and decreased exponentially with immersion time. At 210 W and 17 Pa, all detectable UO 2 in the samples (∼10.6 mg each) was removed at the endpoint, whereas the initial etch rate was ∼3.11 μm/min. When the absorbed power was ≤50 W, however, the etch rate was initially ∼0.5 μg/min and almost zero at the endpoint, with UO 2 only partially etched. This self-limiting etching of UO 2 at low power is attributed to the formation of nonvolatile intermediates UF 2 , UF 3 , UF 4 , UF 5 , UO 2 F, and UO 2 F 2 on the surface. Analysis indicated that the accumulation of UF 6 and, to a lesser extent, O 2 near the surface partially contributed to the exponential decrease in the UO 2 etch rate with immersion time. Unlike fluorination with F 2 gas, etching of UO 2 using rf glow discharge is possible below 663 K. The average etch rates of the amorphous UO 2 in the NF 3 experiments are comparable to the peak values reported in other studies for crystalline UO 2 using CF 4 /O 2 glow discharge performed at ∼150 to 250 K higher sample temperatures

  1. The Chemically Synthesized Ageladine A-Derivative LysoGlow84 Stains Lysosomes in Viable Mammalian Brain Cells and Specific Structures in the Marine Flatworm Macrostomum lignano

    Directory of Open Access Journals (Sweden)

    Thorsten Mordhorst

    2015-02-01

    Full Text Available Based on the chemical structure and the known chemical synthesis of the marine sponge alkaloid ageladine A, we synthesized the ageladine A-derivative 4-(naphthalene-2-yl-1H-imidazo[4,5-c]pyridine trifluoroacetate (LysoGlow84. The two-step synthesis started with the Pictet-Spengler reaction of histamine and naphthalene-2-carbaldehyde to a tetrahydropyridine intermediate, which was dehydrogenated with activated manganese (IV oxide to LysoGlow84. Structure and purity of the synthesized LysoGlow84 were confirmed by NMR spectroscopy and mass spectrometry. The fluorescence intensity emitted by LysoGlow84 depended strongly on the pH of the solvent with highest fluorescence intensity recorded at pH 4. The fluorescence maximum (at 315 nm excitation was observed at 440 nm. Biocompatibility of LysoGlow84 was investigated using cultured rat brain astrocytes and the marine flatworm Macrostomum lignano. Exposure of the astrocytes for up to 6 h to micromolar concentrations of LysoGlow84 did not compromise cell viability, as demonstrated by several viability assays, but revealed a promising property of this compound for staining of cellular vesicles. Conventional fluorescence microscopy as well as confocal scanning microscopy of LysoGlow84-treated astrocytes revealed co-localization of LysoGlow84 fluorescence with that of LysoTracker® Red DND-99. LysoGlow84 stained unclear structures in Macrostomum lignano, which were identified as lysosomes by co-staining with LysoTracker. Strong fluorescence staining by LysoGlow84 was further observed around the worms’ anterior gut and the female genital pore which were not counterstained by LysoTracker Red. Thus, LysoGlow84 is a new promising dye that stains lysosomes and other acidic compartments in cultured cells and in worms.

  2. The chemically synthesized ageladine A-derivative LysoGlow84 stains lysosomes in viable mammalian brain cells and specific structures in the marine flatworm Macrostomum lignano.

    Science.gov (United States)

    Mordhorst, Thorsten; Awal, Sushil; Jordan, Sebastian; Petters, Charlotte; Sartoris, Linda; Dringen, Ralf; Bickmeyer, Ulf

    2015-02-11

    Based on the chemical structure and the known chemical synthesis of the marine sponge alkaloid ageladine A, we synthesized the ageladine A-derivative 4-(naphthalene-2-yl)-1H-imidazo[4,5-c]pyridine trifluoroacetate (LysoGlow84). The two-step synthesis started with the Pictet-Spengler reaction of histamine and naphthalene-2-carbaldehyde to a tetrahydropyridine intermediate, which was dehydrogenated with activated manganese (IV) oxide to LysoGlow84. Structure and purity of the synthesized LysoGlow84 were confirmed by NMR spectroscopy and mass spectrometry. The fluorescence intensity emitted by LysoGlow84 depended strongly on the pH of the solvent with highest fluorescence intensity recorded at pH 4. The fluorescence maximum (at 315 nm excitation) was observed at 440 nm. Biocompatibility of LysoGlow84 was investigated using cultured rat brain astrocytes and the marine flatworm Macrostomum lignano. Exposure of the astrocytes for up to 6 h to micromolar concentrations of LysoGlow84 did not compromise cell viability, as demonstrated by several viability assays, but revealed a promising property of this compound for staining of cellular vesicles. Conventional fluorescence microscopy as well as confocal scanning microscopy of LysoGlow84-treated astrocytes revealed co-localization of LysoGlow84 fluorescence with that of LysoTracker® Red DND-99. LysoGlow84 stained unclear structures in Macrostomum lignano, which were identified as lysosomes by co-staining with LysoTracker. Strong fluorescence staining by LysoGlow84 was further observed around the worms' anterior gut and the female genital pore which were not counterstained by LysoTracker Red. Thus, LysoGlow84 is a new promising dye that stains lysosomes and other acidic compartments in cultured cells and in worms.

  3. Pulsed glow discharge mass spectrometry for molecular depth profiling of polymers

    International Nuclear Information System (INIS)

    Lobo, L.; Pereiro, R.; Sanz-Medel, A.; Bordel, N.; Pisonero, J.; Licciardello, A.; Tuccitto, N.; Tempez, A.; Chapon, P.

    2009-01-01

    Full text: Nowadays thin films of polymeric materials involve a wide range of industrial applications, so techniques capable of providing in-depth profile information are required. Most of the techniques available for this purpose are based on the use of energetic particle beams which interact with polymers producing undesirable physicochemical modifications. Radiofrequency pulsed glow discharge (rf-pulsed-GD) coupled to time-of-flight mass spectrometry (TOFMS) could afford the possibility of acquiring both elemental and molecular information creating minimal damage to surfaces and thereby obtaining depth profiles. This work will evaluate rf-GDs coupled to an orthogonal TOFMS for direct analysis of polymers. (author)

  4. Nonlocal control of electron temperature in short direct current glow discharge plasma

    Energy Technology Data Exchange (ETDEWEB)

    Demidov, V. I. [Department of Optics and Spectroscopy, St. Petersburg State University, St. Petersburg 199034 (Russian Federation); International Laboratory “Nonlocal Plasma in Nanotechnology and Medicine”, ITMO University, Kronverkskiy pr. 49, St. Petersburg 197101 (Russian Federation); Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506 (United States); Kudryavtsev, A. A.; Stepanova, O. M. [Department of Optics and Spectroscopy, St. Petersburg State University, St. Petersburg 199034 (Russian Federation); Kurlyandskaya, I. P. [International Laboratory “Nonlocal Plasma in Nanotechnology and Medicine”, ITMO University, Kronverkskiy pr. 49, St. Petersburg 197101 (Russian Federation); St. Petersburg University of State Fire Service of EMERCOM RF, Murmansk Branch, Murmansk 183040 (Russian Federation)

    2014-09-15

    To demonstrate controlling the electron temperature in nonlocal plasma, experiments have been performed on a short (without positive column) dc glow discharge with a cold cathode by applying different voltages to the conducting discharge wall. The experiments have been performed for low-pressure noble gas discharges. The applied voltage can modify trapping the energetic electrons emitted from the cathode sheath and arising from the atomic and molecular processes in the plasma within the device volume. This phenomenon results in the energetic electrons heating the slow plasma electrons, which consequently modifies the electron temperature. Furthermore, a numerical model of the discharge has demonstrated the electron temperature modification for the above case.

  5. Nitridation Of The A A 2024 T3 Aluminium By The Glow Discharge Plasma Technique

    International Nuclear Information System (INIS)

    Mudjiman, Supardjono; Sujitno, Tjipto; Sudjatmoko

    1996-01-01

    Nitridation of A A 2024 T3 aluminium by means of plasma glow discharge technique has been carried out. For this purpose, the experiments were carried out at the temperature 30 o C, 60 o C, 100 o C, 150 o C, 200 o C, and 250 o C whereas the nitridation time were varied at 5 minutes, 15 minutes, 40 minutes, 90 minutes and 180 minutes. The results showed that the optimum temperature and time of nitridation were 60 o C and 90 minutes respectively and the hardness increased from 115 to 166 KHN

  6. A simple theoretical approach to determine relative ion yield (RIY) in glow discharge mass spectrometry (GDMS)

    International Nuclear Information System (INIS)

    Born, Sabine; Matsunami, Noriaki

    2000-01-01

    Direct current glow discharge mass spectrometry (dc-GDMS) has been applied to detect impurities in metals. The aim of this study is to understand quantitatively the processes taking place in GDMS and establish a model to calculate the relative ion yield (RIY), which is inversely proportional to the relative sensitivity factor (RSF), in order to achieve better agreement between the calculated and the experimental RIYs. A comparison is made between the calculated RIY of the present model and the experimental RIY, and also with other models. (author)

  7. Analysis of green fluorescent protein bioluminescence in vivo and in vitro using a glow discharge

    Science.gov (United States)

    Hernández, L.; Mandujano, L. A.; Cuevas, J.; Reyes, P. G.; Osorio-González, D.

    2015-03-01

    The discovery of fluorescent proteins has been a revolution in cell biology and related sciences because of their many applications, mainly emphasizing their use as cellular markers. The green fluorescent protein (GFP) is one of the most used as it requires no cofactors to generate fluorescence and retains this property into any organism when it is expressed by recombinant DNA techniques, which is a great advantage. In this work, we analyze the emission spectra of recombinant green fluorescent protein in vivo and in vitro exposed to a glow discharge plasma of nitrogen in order to relate electron temperature to fluorescence intensity.

  8. Stabilization of a cold cathode electron beam glow discharge for surface treatment

    Energy Technology Data Exchange (ETDEWEB)

    Mingolo, N.; Gonzalez, C.R. [Lab. de Haces Dirigidos, Depto. de Fisica, Facultad de Ingenieria, Universidad de Buenos Aires, Paseo Colon 850, 1063 Buenos Aires (Argentina); Martinez, O.E. [Lab. de Electronica Cuantica, Depto. de Fisica, Universidad de Buenos Aires, Pabellon 1, Ciudad Universitaria, 1428 Buenos Aires (Argentina); Rocca, J.J. [Department of Electrical Engineering, Colorado State University, Fort Collins, Colorado 80523 (United States)

    1997-10-01

    We have demonstrated that the reproducibility of electron beam pulses generated by a high power, cold cathode glow discharge is greatly improved by adding a small continuous keep-alive discharge current. A current of the order of 200 {mu}A was found to limit the shot to shot current variation to within 1.5{percent}. This stabilization in turn reduces by an order of magnitude the fluctuations of the energy density deposited on the target, demonstrating a reliable energy source for surface treatment. {copyright} {ital 1997 American Institute of Physics.}

  9. Elongated dust particles growth in a spherical glow discharge in ethanol

    Science.gov (United States)

    Fedoseev, A. V.; Sukhinin, G. I.; Sakhapov, S. Z.; Zaikovskii, A. V.; Novopashin, S. A.

    2018-01-01

    The formation of elongated dust particles in a spherical dc glow discharge in ethanol was observed for the first time. Dust particles were formed in the process of coagulation of ethanol dissociation products in the plasma of gas discharge. During the process the particles were captured into clouds in the electric potential wells of strong striations of spherical discharge. The size and the shape of dust particles are easily detected by naked eye after the illumination of the laser sheet. The description of the experimental setup and conditions, the analysis of size, shape and composition of the particles, the explanation of spatial ordering and orientation of these particles are presented.

  10. Sputtering in a glow discharge ion source - pressure dependence: theory and experiment

    International Nuclear Information System (INIS)

    Mason, R.S.; Pichilingi, Melanie

    1994-01-01

    A simplified theoretical expression has been developed for a glow discharge to show how the average cathode erosion rate (expressed as the number of atoms per ion of the total bombarding flux) varies with primary sputter yield, pressure, 'diffusion length' and sputtered atom 'stopping' cross section. An inverse pressure dependence is predicted which correlates well with experiment in the 2 and He, tend to converge. It is suggested that this could be due to a change in the mechanism to self-sputtering. Under constant conditions, the erosion rates of different cathode materials still correlate quite well with the differences in their primary sputter yields. (author)

  11. Optical observations of Magnetosphere-Ionosphere coupling: Inter-hemispheric electron reflections within pulsating aurora

    Science.gov (United States)

    Samara, M.; Michell, R.; Khazanov, G. V.; Grubbs, G. A., II

    2017-12-01

    Magnetosphere-Ionosphere coupling is exhibited in reflected primary and secondary electrons which constitute the second step in the formation of the total precipitating electron distribution. While they have largely been missing from the current theoretical studies of particle precipitation, ground based observations point to the existence of a reflected electron population. We present evidence that pulsating aurora is caused by electrons bouncing back and forth between the two hemispheres. This means that these electrons are responsible for some of the total light in the aurora, a possibility that has largely been ignored in theoretical models. Pulsating auroral events imaged optically at high time resolution present direct observational evidence in agreement with the inter-hemispheric electron bouncing predicted by the SuperThermal Electron Trans-port (STET) model. Immediately following each of the `pulsation-on' times are equally spaced, and subsequently fainter pulsations, which can be explained by the primary precipitating electrons reflecting upwards from the ionosphere, traveling to the opposite hemisphere, and reflecting upwards again. The high time-resolution of these data, combined with the short duration of the `pulsation-on' time ( 1 s) and the relatively long spacing between pulsations ( 6 to 9 s) made it possible to observe the faint optical pulses caused by the reflected electrons coming from the opposite hemisphere. These results are significant and have broad implications because they highlight that the formation of the auroral electron distributions within regions of diffuse and pulsating aurora contain contributions from reflected primary and secondary electrons. These processes can ultimately lead to larger fluxes than expected when considering only the primary injection of magnetospheric electrons.

  12. A Dual Non-ATP Analogue Inhibitor of Aurora Kinases A and B, Derived from Resorcinol with a Mixed Mode of Inhibition.

    Science.gov (United States)

    Karthigeyan, Dhanasekaran; Surabhi, Sudhevan; Mizar, Pushpak; Soumik, Siddhanta; Banerjee, Amrita; Sinha, Sarmistha Halder; Dasgupta, Dipak; Narayana, Chandrabhas; Kundu, Tapas K

    2016-06-01

    Aurora kinases are the most commonly targeted mitotic kinases in the intervention of cancer progression. Here, we report a resorcinol derivative, 5-methyl-4-(2-thiazolylazo) resorcinol (PTK66), a dual inhibitor of Aurora A and Aurora B kinases. PTK66 is a surface binding non-ATP analogue inhibitor that shows a mixed pattern of inhibition against both of Aurora A and B kinases. The in vitro IC50 is approximately 47 and 40 μm for Aurora A and Aurora B kinases, respectively. In cellular systems, PTK66 exhibits a substantially low cytotoxicity at micromolar concentrations but it can induce aneuploidy under similar dosages as a consequence of Aurora kinase inhibition. This result was corroborated by a drop in the histone H3 (S10) phosphorylation level detected via Western blot analysis using three different cell types. Altogether, our findings indicate that the ligand containing resorcinol backbone is one of the novel scaffolds targeting the Aurora family of kinases, which could be a target for antineoplastic drug development. © 2016 John Wiley & Sons A/S.

  13. Polare maskuliniteter

    Directory of Open Access Journals (Sweden)

    Marit Anne Hauan

    2012-05-01

    Full Text Available In this paper my aim is to read and understand the journal of Gerrit de Veer from the last journey of William Barents to the Arctic Regions in 1596 and the journal of captain Junge on his hunting trip from Tromsø to Svalbard in 1834.It is nearly 240 years between this to voyages. The first journal is known as the earliest report from the arctic era. Gerrit de Veer adds instructive copper engravings to his text and give us insight in the crews meeting with this new land. Captain Junges journal is found together with his dead crew in a house in a fjord nearby Ny-Ålesund and has no drawings, but word. Both of these journals may be read as sources of the knowledge and understanding of the polar region. They might also unveil the ideas of how to deal with and survive under the challenges that is given. In addition one can ask if the sources can tell us more about how men describe their challenges. Can the way they expressed themselves in the journals give us an understanding of masculinity? And not least help us to create good questions of the change in the ideas of masculinities which is said to follow the change in understanding of the wilderness.

  14. Search for Potent and Selective Aurora A Inhibitors Based on General Ser/Thr Kinase Pharmacophore Model

    Directory of Open Access Journals (Sweden)

    Natalya I. Vasilevich

    2016-04-01

    Full Text Available Based on the data for compounds known from the literature to be active against various types of Ser/Thr kinases, a general pharmachophore model for these types of kinases was developed. The search for the molecules fitting to this pharmacophore among the ASINEX proprietary library revealed a number of compounds, which were tested and appeared to possess some activity against Ser/Thr kinases such as Aurora A, Aurora B and Haspin. Our work on the optimization of these molecules against Aurora A kinase allowed us to achieve several hits in a 3–5 nM range of activity with rather good selectivity and Absorption, Distribution, Metabolism, and Excretion (ADME properties, and cytotoxicity against 16 cancer cell lines. Thus, we showed the possibility to fine-tune the general Ser/Thr pharmacophore to design active and selective compounds against desired types of kinases.

  15. On the variability of I(7620 Å/I(5577 Å in low altitude aurora

    Directory of Open Access Journals (Sweden)

    E. J. Llewellyn

    Full Text Available An auroral electron excitation model, combined with simple equilibrium neutral and ion chemistry models, is used to investigate the optical emission processes and height profiles of I(5577 Å and I(7620 Å in the 90 to 100 km altitude region. It is shown that the apparent discrepancies between ground-based and rocket-borne auroral observations of the I(7620 Å/I(5577 Å ratio are due to the extreme height variation of this intensity ratio in the 90 to 100 km region.

    Key words. Atmospheric composition and structure (airglow and aurora

  16. On the variability of I(7620 Å/I(5577 Å in low altitude aurora

    Directory of Open Access Journals (Sweden)

    E. J. Llewellyn

    1999-07-01

    Full Text Available An auroral electron excitation model, combined with simple equilibrium neutral and ion chemistry models, is used to investigate the optical emission processes and height profiles of I(5577 Å and I(7620 Å in the 90 to 100 km altitude region. It is shown that the apparent discrepancies between ground-based and rocket-borne auroral observations of the I(7620 Å/I(5577 Å ratio are due to the extreme height variation of this intensity ratio in the 90 to 100 km region.Key words. Atmospheric composition and structure (airglow and aurora

  17. Indole Alkaloids from the Sea Anemone Heteractis aurora and Homarine from Octopus cyanea.

    Science.gov (United States)

    Shaker, Kamel H; Göhl, Matthias; Müller, Tobias; Seifert, Karlheinz

    2015-11-01

    The two new indole alkaloids 2-amino-1,5-dihydro-5-(1H-indol-3-ylmethyl)-4H-imidazol-4-one (1), 2-amino-5-[(6-bromo-1H-indol-3-yl)methyl]-3,5-dihydro-3-methyl-4H-imidazol-4-one (2), and auramine (3) have been isolated from the sea anemone Heteractis aurora. Both indole alkaloids were synthesized for the confirmation of the structures. Homarine (4), along with uracil (5), hypoxanthine (6), and inosine (7) have been obtained from Octopus cyanea. Copyright © 2015 Verlag Helvetica Chimica Acta AG, Zürich.

  18. Applications of the Aurora parallel Prolog system to computational molecular biology

    Energy Technology Data Exchange (ETDEWEB)

    Lusk, E.L.; Overbeek, R. [Argonne National Lab., IL (United States); Mudambi, S. [Knox Coll., Galesburg, IL (United States); Szeredi, P. [IQSOFT, Budapest (Hungary)

    1993-09-01

    We describe an investigation into the use of the Aurora parallel Prolog system in two applications within the area of computational molecular biology. The computational requirements were large, due to the nature of the applications, and were large, due to the nature of the applications, and were carried out on a scalable parallel computer the BBN ``Butterfly`` TC-2000. Results include both a demonstration that logic programming can be effective in the context of demanding applications on large-scale parallel machines, and some insights into parallel programming in Prolog.

  19. Multi-pin-to-plate atmospheric glow discharge for the removal of volatile organic compounds in waste air

    International Nuclear Information System (INIS)

    Vertriest, R; Morent, R; Dewulf, J; Leys, C; Langenhove, H van

    2003-01-01

    A DC-excited atmospheric pressure glow discharge in a multi-pin-to-plate electrode configuration is applied to the removal of trichloroethylene (TCE) in air. A removal fraction of up to 47% is obtained at an energy density of 35 J litre -1 (air flow rate: 60 m 3 h -1 ; residence time: 50 ms; TCE inlet concentration: 120 ppm; temperature: 298 K). The addition of TCE increases the discharge impedance and improves the uniformity of the current distribution in the direction of the gas flow. In the investigated inlet concentration range (0-160 ppm), no influence of the TCE admixture is observed on the corona-to-glow and glow-to-spark threshold currents. Experiments with other volatile organic compounds (VOCs) reveal that molecules containing a double carbon bond have the lowest energy requirement for decomposition

  20. Metformin disrupts malignant behavior of oral squamous cell carcinoma via a novel signaling involving Late SV40 factor/Aurora-A.

    Science.gov (United States)

    Chen, Chang-Han; Tsai, Hsin-Ting; Chuang, Hui-Ching; Shiu, Li-Yen; Su, Li-Jen; Chiu, Tai-Jan; Luo, Sheng-Dean; Fang, Fu-Min; Huang, Chao-Cheng; Chien, Chih-Yen

    2017-05-02

    Conventional therapeutic processes in patient with OSCC are associated with several unfavorable effects leading to patients with poor survival rate. Metformin has been shown to protect against a variety of specific diseases, including cancer. However, the precise roles and mechanisms underlying the therapeutic effects of metformin on OSCC remain elusive. In the current study, in vitro and xenograft model experiments revealed that metformin inhibited growth and metastasis of oral cancer cells. Importantly, metformin-restrained tumorigenesis of oral cancer was accompanied with strong decrease of both Aurora-A and Late SV40 Factor (LSF) expressions. Furthermore, LSF contributed to Aurora-A-elicited malignancy behaviors of oral cancer via binding to the promoter region of Aurora-A. A significant correlation was observed between LSF and Aurora-A levels in a cohort of specimens of oral cancer. These findings showed that a novel LSF/Aurora-A-signaling inhibition supports the rationale of using metformin as potential OSCC therapeutics.

  1. On the physical processes ruling an atmospheric pressure air glow discharge operating in an intermediate current regime

    Energy Technology Data Exchange (ETDEWEB)

    Prevosto, L., E-mail: prevosto@waycom.com.ar; Mancinelli, B.; Chamorro, J. C.; Cejas, E. [Grupo de Descargas Eléctricas, Departamento Ing. Electromecánica, Facultad Regional Venado Tuerto (UTN), Laprida 651, Venado Tuerto (2600), Santa Fe (Argentina); Kelly, H. [Grupo de Descargas Eléctricas, Departamento Ing. Electromecánica, Facultad Regional Venado Tuerto (UTN), Laprida 651, Venado Tuerto (2600), Santa Fe (Argentina); Instituto de Física del Plasma (CONICET), Facultad de Ciencias Exactas y Naturales (UBA) Ciudad Universitaria Pab. I, 1428, Buenos Aires (Argentina)

    2015-02-15

    Low-frequency (100 Hz), intermediate-current (50 to 200 mA) glow discharges were experimentally investigated in atmospheric pressure air between blunt copper electrodes. Voltage–current characteristics and images of the discharge for different inter-electrode distances are reported. A cathode-fall voltage close to 360 V and a current density at the cathode surface of about 11 A/cm{sup 2}, both independent of the discharge current, were found. The visible emissive structure of the discharge resembles to that of a typical low-pressure glow, thus suggesting a glow-like electric field distribution in the discharge. A kinetic model for the discharge ionization processes is also presented with the aim of identifying the main physical processes ruling the discharge behavior. The numerical results indicate the presence of a non-equilibrium plasma with rather high gas temperature (above 4000 K) leading to the production of components such as NO, O, and N which are usually absent in low-current glows. Hence, the ionization by electron-impact is replaced by associative ionization, which is independent of the reduced electric field. This leads to a negative current-voltage characteristic curve, in spite of the glow-like features of the discharge. On the other hand, several estimations show that the discharge seems to be stabilized by heat conduction; being thermally stable due to its reduced size. All the quoted results indicate that although this discharge regime might be considered to be close to an arc, it is still a glow discharge as demonstrated by its overall properties, supported also by the presence of thermal non-equilibrium.

  2. Non-parametric Data Analysis of Low-latitude Auroras and Naked-eye Sunspots in the Medieval Epoch

    Science.gov (United States)

    Bekli, Mohamed Reda; Zougab, Nabil; Belabbas, Abdelmoumene; Chadou, Ilhem

    2017-04-01

    We have studied solar activity by analyzing naked-eye sunspot observations and aurorae borealis observed at latitudes below 45°. We focused on the medieval epoch by considering the non-telescopic observations of sunspots from AD 974 to 1278 and aurorae borealis from AD 965 to 1273 that are reported in several Far East historical sources, primarily in China and Korea. After setting selection rules, we analyzed the distribution of these individual events following the months of the Gregorian calendar. In December, an unusual peak is observed with data recorded in both China and Japan, but not within Korean data.

  3. Tanshinones inhibit the growth of breast cancer cells through epigenetic modification of Aurora A expression and function.

    Directory of Open Access Journals (Sweden)

    Yi Gong

    Full Text Available The objectives of this study were to evaluate the effects of tanshinones from a Chinese herb Salvia Miltiorrhiza on the growth of breast cancer cells, and to elucidate cellular and molecular mechanisms of action. Tanshinones showed the dose-dependent effect on the growth inhibition of breast cancer cells in vitro, with tanshinone I (T1 the most potent agent. T1 was also the only tanshinone to have potent activity in inhibiting the growth of the triple-negative breast cancer cell line MDA-MB231. T1 caused cell cycle arrests of both estrogen-dependent and estrogen-independent cell lines associated with alterations of cyclinD, CDK4 and cyclinB, and induced breast cancer cell apoptosis associated with upregulation of c-PARP and downregulation of survivin and Aurora A. Among these associated biomarkers, Aurora A showed the most consistent pattern with the anti-growth activity of tanshinones. Overexpression of Aurora A was also verified in breast tumors. The gene function assay showed that knockdown of Aurora A by siRNA dramatically reduced the growth-inhibition and apoptosis-induction activities of T1, suggesting Aurora A as an important functional target of T1 action. On the other hand, tanshinones had much less adverse effects on normal mammary epithelial cells. Epigenetic mechanism studies showed that overexpression of Aurora A gene in breast cancer cells was not regulated by gene promoter DNA methylation, but by histone acetylation. T1 treatment significantly reduced acetylation levels of histone H3 associated with Aurora A gene. Our results supported the potent activity of T1 in inhibiting the growth of breast cancer cells in vitro in part by downregulation of Aurora A gene function. Our previous studies also demonstrated that T1 had potent anti-angiogenesis activity and minimal side effects in vivo. Altogether, this study warrants further investigation to develop T1 as an effective and safe agent for the therapy and prevention of breast cancer.

  4. AGING EFFECTS OF REPEATEDLY GLOW-DISCHARGED POLYETHYLENE - INFLUENCE ON CONTACT-ANGLE, INFRARED-ABSORPTION, ELEMENTAL SURFACE-COMPOSITION, AND SURFACE-TOPOGRAPHY

    NARCIS (Netherlands)

    VANDERMEI, HC; STOKROOS, [No Value; SCHAKENRAAD, JM; BUSSCHER, HJ

    1991-01-01

    Aging effects of repeatedly oxygen glow-discharged polyethylene surfaces were determined by water contact angle measurements, infrared (IR) spectroscopy, X-ray photoelectron (XPS) spectroscopy, and surface topography determination. Glow-discharged surfaces were stored at room temperature and in

  5. Induction of p21CIP1 protein and cell cycle arrest after inhibition of Aurora B kinase is attributed to aneuploidy and reactive oxygen species.

    Science.gov (United States)

    Kumari, Geeta; Ulrich, Tanja; Krause, Michael; Finkernagel, Florian; Gaubatz, Stefan

    2014-06-06

    Cell cycle progression requires a series of highly coordinated events that ultimately lead to faithful segregation of chromosomes. Aurora B is an essential mitotic kinase, which is involved in regulation of microtubule-kinetochore attachments and cytokinesis. Inhibition of Aurora B results in stabilization of p53 and induction of p53-target genes such as p21 to inhibit proliferation. We have previously demonstrated that induction of p21 by p53 after inhibition of Aurora B is dependent on the p38 MAPK, which promotes transcriptional elongation of p21 by RNA Pol II. In this study, we show that a subset of p53-target genes are induced in a p38-dependent manner upon inhibition of Aurora B. We also demonstrate that inhibition of Aurora B results in down-regulation of E2F-mediated transcription and that the cell cycle arrest after Aurora B inhibition depends on p53 and pRB tumor suppressor pathways. In addition, we report that activation of p21 after inhibition of Aurora B is correlated with increased chromosome missegregation and aneuploidy but not with binucleation or tetraploidy. We provide evidence that p21 is activated in aneuploid cells by reactive oxygen species (ROS) and p38 MAPK. Finally, we demonstrate that certain drugs that act on aneuploid cells synergize with inhibitors of Aurora B to inhibit colony formation and oncogenic transformation. These findings provide an important link between aneuploidy and the stress pathways activated by Aurora B inhibition and also support the use of Aurora B inhibitors in combination therapy for treatment of cancer. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  6. Phosphorylation of NuMA by Aurora-A kinase in PC-3 prostate cancer cells affects proliferation, survival, and interphase NuMA localization.

    Science.gov (United States)

    Toughiri, Raheleh; Li, Xiang; Du, Quansheng; Bieberich, Charles J

    2013-04-01

    Aurora-A is a serine/threonine kinase that has oncogenic properties in vivo. The expression and kinase activity of Aurora-A are up-regulated in multiple malignancies. Aurora-A is a key regulator of mitosis that localizes to the centrosome from the G2 phase through mitotic exit and regulates mitotic spindle formation as well as centrosome separation. Overexpression of Aurora-A in multiple malignancies has been linked to higher tumor grade and poor prognosis through mechanisms that remain to be defined. Using an unbiased proteomics approach, we identified the protein nuclear mitotic apparatus (NuMA) as a robust substrate of Aurora-A kinase. Using a small molecule Aurora-A inhibitor in conjunction with a reverse in-gel kinase assay (RIKA), we demonstrate that NuMA becomes hypo-phosphorylated in vivo upon Aurora-A inhibition. Using an alanine substitution strategy, we identified multiple Aurora-A phospho-acceptor sites in the C-terminal tail of NuMA. Functional analyses demonstrate that mutation of three of these phospho-acceptor sites significantly diminished cell proliferation. In addition, alanine mutation at these sites significantly increased the rate of apoptosis. Using confocal immunofluorescence microscopy, we show that the NuMA T1804A mutant mis-localizes to the cytoplasm in interphase nuclei in a punctate pattern. The identification of Aurora-A phosphorylation sites in NuMA that are important for cell cycle progression and apoptosis provides new insights into Aurora-A function. Copyright © 2012 Wiley Periodicals, Inc.

  7. Polar ionospheric responses to solar wind IMF changes

    Directory of Open Access Journals (Sweden)

    Y. Zhang

    2000-06-01

    Full Text Available Auroral and airglow emissions over Eureka (89° CGM during the 1997-98 winter show striking variations in relation to solar wind IMF changes. The period January 19 to 22, 1998, was chosen for detailed study, as the IMF was particularly strong and variable. During most of the period, Bz was northward and polar arcs were observed. Several overpasses by DMSP satellites during the four day period provided a clear picture of the particle precipitation producing the polar arcs. The spectral character of these events indicated excitation by electrons of average energy 300 to 500 eV. Only occasionally were electrons of average energy up to ~1 keV observed and these appeared transitory from the ground optical data. It is noted that polar arcs appear after sudden changes in IMF By, suggesting IMF control over arc initiation. When By is positive there is arc motion from dawn to dusk, while By is negative the motion is consistently dusk to dawn. F-region (anti-sunward convections were monitored through the period from 630.0 nm emissions. The convection speed was low (100-150 m/s when Bz was northward but increased to 500 m/s after Bz turned southward on January 20.Key words: Atmospheric composition and structure (airglow and aurora - Ionosphere (particle precipitation - Magnetospheric Physics (polar cap phenomena

  8. PRODUCTION OF HIGHER STRENGTH THIN WALLED GLOW DISCHARGE POLYMER SHELLS FOR CRYOGENIC EXPERIMENTS AT OMEGA

    International Nuclear Information System (INIS)

    NIKROO, A; CZECHOWICZ, DG; CASTILLO, ER; PONTELANDOLFO, JM

    2002-01-01

    OAK A271 PRODUCTION OF HIGHER STRENGTH THIN WALLED GLOW DISCHARGE POLYMER SHELLS FOR CRYOGENIC EXPERIMENTS AT OMEGA. Thin walled polymer shells are needed for OMEGA cryogenic laser experiments. These capsules need to be about 900 (micro)m in diameter and as thin as possible (approx 1-2 (micro)m), while having enough strength to be filled with DT as fast as possible to about 1000 atm. The authors have found that by optimizing the coating parameters in the glow discharge polymer (GDP) deposition system, traditionally used for making ICF targets, they can routinely make robust, ∼ 1.5 (micro)m thick, 900 (micro)m diameter GDP shells with buckle strengths of over 0.3 atm. This is twice the strength of shells made prior to the optimization and is comparable to values quoted for polyimide shells. In addition, these shells were found to be approximately three times more permeable and over 20% denser than previously made GDP shells. The combination of higher strength and permeability is ideal for direct drive cryogenic targets at OMEGA. Shells as thin as 0.5 (micro)m have been made. In this paper, the authors discuss the shell fabrication process, effects of modifying various GDP deposition parameters on shell properties and chemical composition

  9. DC glow microdischarge with a self-determined length in helium and argon at atmospheric pressure

    Science.gov (United States)

    Astafiev, Alexander; Kudryavtsev, Anatoly; Stepanova, Olga; Belyaev, Vladimir; Zamchy, Roman; Chen, Zhaoquan

    2018-02-01

    The spatial characteristics of a stable DC glow microdischarge with currents of 1-20 mA ignited between a flat cathode and truncated cylindrical anode with a diameter of 100 μm in helium and argon at atmospheric pressure were studied. The focus of the present study is on the examination of the experimental conditions to obtain a stable and homogeneous state of the microdischarge at an electrode gap of 15-1500 μm. It is shown that such conditions are fulfilled when the parameter pL0 (p—gas pressure at 300 K; L0—electrode gap) corresponds to the values near the minimum of the Paschen curve, and the microdischarge choses its length, that is the microdischarge has a self-determined length. The main measured parameters are the voltage drops across the electrode gap and the discharge currents. In addition, the size and shape of the negative glow region of the discharge, cathode current density, and other characteristics were estimated.

  10. Quantum machine learning with glow for episodic tasks and decision games

    Science.gov (United States)

    Clausen, Jens; Briegel, Hans J.

    2018-02-01

    We consider a general class of models, where a reinforcement learning (RL) agent learns from cyclic interactions with an external environment via classical signals. Perceptual inputs are encoded as quantum states, which are subsequently transformed by a quantum channel representing the agent's memory, while the outcomes of measurements performed at the channel's output determine the agent's actions. The learning takes place via stepwise modifications of the channel properties. They are described by an update rule that is inspired by the projective simulation (PS) model and equipped with a glow mechanism that allows for a backpropagation of policy changes, analogous to the eligibility traces in RL and edge glow in PS. In this way, the model combines features of PS with the ability for generalization, offered by its physical embodiment as a quantum system. We apply the agent to various setups of an invasion game and a grid world, which serve as elementary model tasks allowing a direct comparison with a basic classical PS agent.

  11. Glow discharge optical emission spectroscopy for accurate and well resolved analysis of coatings and thin films

    KAUST Repository

    Wilke, Marcus

    2011-12-01

    In the last years, glow discharge optical emission spectrometry (GDOES) gained more and more acceptance in the analysis of functional coatings. GDOES thereby represents an interesting alternative to common depth profiling techniques like AES and SIMS, based on its unique combination of high erosion rates and erosion depths, sensitivity, analysis of nonconductive layers and easy quantification even for light elements such as C, N, O and H. Starting with the fundamentals of GDOES, a short overview on new developments in instrument design for accurate and well resolved thin film analyses is presented. The article focuses on the analytical capabilities of glow discharge optical emission spectrometry in the analysis of metallic coatings and thin films. Results illustrating the high depth resolution, confirmation of stoichiometry, the detection of light elements in coatings as well as contamination on the surface or interfaces will be demonstrated by measurements of: a multilayer system Cr/Ti on silicon, interface contamination on silicon during deposition of aluminum, Al2O3-nanoparticle containing conversion coatings on zinc for corrosion resistance, Ti3SiC2 MAX-phase coatings by pulsed laser deposition and hydrogen detection in a V/Fe multilayer system. The selected examples illustrate that GDOES can be successfully adopted as an analytical tool in the development of new materials and coatings. A discussion of the results as well as of the limitations of GDOES is presented. © 2011 Elsevier B.V.

  12. Modeling of high frequency atmospheric pressure Ar/H2/SiH4 glow discharges

    International Nuclear Information System (INIS)

    Zhuang Juan; Sun Jizhong; Wang Dezhen; Sang Chaofeng; Liu Liying

    2011-01-01

    In this paper, a one-dimensional self-consistent fluid model is applied to simulate high frequency atmospheric pressure glow discharges. The results show that the plasma density and current density depend strongly on the excitation frequency. When the excitation frequency is below 13.56 MHz, the discharge operates in the α mode, and when the excitation frequency is above 13.56 MHz, the discharge operates in a γ-like mode. The densities of species including SiH 3 + , SiH 3 - , SiH 3 , SiH 2 , H, Ar + , Ar* and electron are enhanced with the frequency increasing from 6.78 to 27.12 MHz. Similar discharge mode transition was observed experimentally in radio frequency atmospheric pressure He glow discharges. The effects of excitation frequency on plasma characteristics and densities of precursors for μc-Si:H film are further discussed. This study reveals that an appropriate excitation frequency is important for the growth of μc-Si:H film.

  13. Surface modification of polytetrafluoroethylene film using the atmospheric pressure glow discharge in air

    International Nuclear Information System (INIS)

    Fang, Z; Qiu, Y; Luo, Y

    2003-01-01

    The atmospheric pressure glow discharge (APGD) is more promising in industrial applications compared with glow discharges in a gas other than air or in low-pressure air, which needs an expensive vacuum system. In this paper, the APGD and dielectric barrier discharge (DBD) are generated in atmospheric air using a power-frequency voltage source, and the transition from DBD to APGD is achieved by varying the electrode arrangement. The differences between their discharge characteristics are shown by measurement of their electrical discharge parameters and observation of light-emission phenomena. The effects of APGD and DBD on polytetrafluoroethylene (PTFE) surface modification are studied. The surface properties are characterized by contact angle measurement, x-ray photoelectron spectroscopy and scanning electron microscopy. It is found that the APGD and DBD treatments modify the PTFE surface in both morphology and composition. APGD is more effective in PTFE surface modification than DBD as it can modify the surface more uniformly, implant more oxygen atoms into the surface and make the contact angle decline to a lower level. The experimental results are discussed

  14. Decomposition of toluene in a steady-state atmospheric-pressure glow discharge

    Science.gov (United States)

    Trushkin, A. N.; Grushin, M. E.; Kochetov, I. V.; Trushkin, N. I.; Akishev, Yu. S.

    2013-02-01

    Results are presented from experimental studies of decomposition of toluene (C6H5CH3) in a polluted air flow by means of a steady-state atmospheric pressure glow discharge at different water vapor contents in the working gas. The experimental results on the degree of C6H5CH3 removal are compared with the results of computer simulations conducted in the framework of the developed kinetic model of plasma chemical decomposition of toluene in the N2: O2: H2O gas mixture. A substantial influence of the gas flow humidity on toluene decomposition in the atmospheric pressure glow discharge is demonstrated. The main mechanisms of the influence of humidity on C6H5CH3 decomposition are determined. The existence of two stages in the process of toluene removal, which differ in their duration and the intensity of plasma chemical decomposition of C6H5CH3 is established. Based on the results of computer simulations, the composition of the products of plasma chemical reactions at the output of the reactor is analyzed as a function of the specific energy deposition and gas flow humidity. The existence of a catalytic cycle in which hydroxyl radical OH acts a catalyst and which substantially accelerates the recombination of oxygen atoms and suppression of ozone generation when the plasma-forming gas contains water vapor is established.

  15. Decomposition of toluene in a steady-state atmospheric-pressure glow discharge

    International Nuclear Information System (INIS)

    Trushkin, A. N.; Grushin, M. E.; Kochetov, I. V.; Trushkin, N. I.; Akishev, Yu. S.

    2013-01-01

    Results are presented from experimental studies of decomposition of toluene (C 6 H 5 CH 3 ) in a polluted air flow by means of a steady-state atmospheric pressure glow discharge at different water vapor contents in the working gas. The experimental results on the degree of C 6 H 5 CH 3 removal are compared with the results of computer simulations conducted in the framework of the developed kinetic model of plasma chemical decomposition of toluene in the N 2 : O 2 : H 2 O gas mixture. A substantial influence of the gas flow humidity on toluene decomposition in the atmospheric pressure glow discharge is demonstrated. The main mechanisms of the influence of humidity on C 6 H 5 CH 3 decomposition are determined. The existence of two stages in the process of toluene removal, which differ in their duration and the intensity of plasma chemical decomposition of C 6 H 5 CH 3 is established. Based on the results of computer simulations, the composition of the products of plasma chemical reactions at the output of the reactor is analyzed as a function of the specific energy deposition and gas flow humidity. The existence of a catalytic cycle in which hydroxyl radical OH acts a catalyst and which substantially accelerates the recombination of oxygen atoms and suppression of ozone generation when the plasma-forming gas contains water vapor is established.

  16. Borax as flux on sintering of iron Ancor Steel 1000® under glow discharge

    Science.gov (United States)

    Ariza Suarez, H. G.; Sarmiento Santos, A.; Ortiz Otálora, C. A.

    2016-02-01

    This work studies the flux effect of borax (di sodium tetraborate decahydrate) on sintering of iron Ancor Steel 1000® in abnormal glow discharge. The incidence of the percentage by weight of borax and the sintering temperature in the process were observed. Samples of powder metallurgical iron were prepared with proportions of 0.50%, 2.0%, 4.0% and 6.0% by weight of borax using the procedures of powder metallurgy. The samples were sintered at 800 and 1100°C for 30min, by glow discharge at low pressure in a reducing atmosphere composed of 20% H2+80% Ar. The samples in compact green-state were analyzed by TGA-DSC to determine the fusion process and mass loss during sintering. The analysis of microhardness and density, shows that at a sintering temperature of 800°C the sample density decreases and the sample microhardness increases with respect to sintered samples without borax. Sintered samples were analysed by DRX showing the absence of precipitates.

  17. New after-glow color images from some rock slices irradiated with γ-rays

    International Nuclear Information System (INIS)

    Hashimoto, Tetsuo; Sakaue, Shuei; Kojima, Motoshi; Sakai, Tadashi

    1991-01-01

    A new observation method of colored luminescence or after-glow (phosphorescence), emitted from rock slices immediately after γ-ray irradiation, has been developed using a normal color-film. The film was directly faced to the irradiated slices for a relatively short period like 2-5 min in a black bag. According to this simple procedure, the resultant photographs showed unexpectedly colorful images depending on the mineral constituents in slices. The intensities of the after-glow color images (referred to as AGCI) were found to be dependent on the dose rates rather than total doses. In the AGCI, the apparent variations of emission intensity were observed even within individual minerals as well as color changes affected by thermal metamorphism. A qualitative decay behavior has been clearly seen in the successive AGCI results. The proposed conventional AGCI technique is considered to become a promising tool applicable to varieties of mineralogical investigations as well as the additional information concerning the intrinsic physical properties of other solid materials. (author)

  18. Fluid modeling on the filament interaction and pattern evolution in glow DBD

    Science.gov (United States)

    Li, Ben; Cui, Ruilin; Li, Ping; Ouyang, Jiting

    2018-01-01

    In this paper, we report on the investigation on filament interaction and pattern evolution in glow DBD regime by using a fluid model. The aim is to find the leading mechanism controlling the filamentary dynamic behaviors. Space-charge and voltage (or surface-charge) fluctuations are introduced into the discharge space to trigger initial non-uniformity of glow DBDs. Filamentary dynamic behaviors of generation and annihilation, merging and splitting, and attraction and repulsion are observed in interaction and evolution process under both kinds of fluctuations. It is found that, localized lateral electric field and its induced electron-focusing effect (EFE) should be the controlling mechanism, which is significantly influenced by discharge intensity, filament diameter and distance. If neighboring discharge channels connect or partially overlap with each other, they will attract and merge under the combined effect of lateral bi-diffusion and EFE. The fluid model and a dynamic model based on voltage transfer character are compared from basic physics and reach good unification.

  19. In-situ reactive glow discharge cleaning of NSLS distributed ion pumps

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, E.D.; Chou, T.S.

    1988-01-01

    Based on our experience with the in-situ cleaning of optical systems by reactive r.f. glow discharges and the conditioning and preparation of distributed ion pump (DIP) elements, we have sought to develop strategies for recovering from severe vacuum accidents by restoring DIP elements of storage rings such as those at the NSLS in-situ. In this paper we will describe a series of experiments conducted in a test apparatus to condition a so called ''egg-crate'' DIP in-situ, (this older type element being common in older storage rings). A new untreated element which was unable to pump below 5x10 /sup /minus/8/ Torr in its initial condition was treated in oxygen and subsequent argon r.f. discharges utilizing the pump element as the discharge electrode producing a nitrogen pumping speed of 168 l/s at 2x10 /sup /minus/8/ Torr. A light bake at 75/degree/C increased this to nearly 500 l/s at 5x10 /sup /minus/8/ Torr. After exposure to atmosphere the speed was reduced to nil at these pressures but subsequently recovered, without bakeout, by glow discharge cleaning. 22 refs., 6 figs.

  20. Transmission characteristics of microwave in a glow-discharge dusty plasma

    Science.gov (United States)

    Jia, Jieshu; Yuan, Chengxun; Gao, Ruilin; Liu, Sha; Yue, Feng; Wang, Ying; Zhou, Zhong-Xiang; Wu, Jian; Li, Hui

    2016-07-01

    In this study, the propagation characteristics of electromagnetic wave in a glow discharge plasma with dust particles are experimentally investigated. A helium alternating current glow discharge plasmas have been successfully generated. Measurements of the plasma parameters using Langmuir probes, in the absence of dust particles, provide plasma densities (ne) of 1017 m-3 and electron temperatures (Te) ranging from 2 to 4 eV. Dusty plasmas are made by adding 30 nm radius aluminum oxide (Al2O3) particles into the helium plasma. The density of the dust particle (nd) in the device is about 1011-1012 m-3. The propagation characteristics of electromagnetic waves are determined by a vector network analyzer with 4-6 GHz antennas. An apparent attenuation by the dust is observed, and the measured attenuation data are approximately in accordance with the theoretical calculations. The effects of gas pressure and input power on the propagation are also investigated. Results show that the transmission attenuation increases with the gas pressure and input power, the charged dust particles play a significant role in the microwave attenuation.

  1. Investigation of helium ion production in constricted direct current plasma ion source with layered-glows

    Science.gov (United States)

    Lee, Yuna; Chung, Kyoung-Jae; Park, Yeong-Shin; Hwang, Y. S.

    2014-02-01

    Generation of helium ions is experimentally investigated with a constricted direct current (DC) plasma ion source operated at layered-glow mode, in which electrons could be accelerated through multiple potential structures so as to generate helium ions including He2+ by successive ionization collisions in front of an extraction aperture. The helium discharge is sustained with the formation of a couple of stable layers and the plasma ball with high density is created near the extraction aperture at the operational pressure down to 0.6 Torr with concave cathodes. The ion beam current extracted with an extraction voltage of 5 kV is observed to be proportional to the discharge current and inversely proportional to the operating pressure, showing high current density of 130 mA/cm2 and power density of 0.52 mA/cm2/W. He2+ ions, which were predicted to be able to exist due to multiple-layer potential structure, are not observed. Simple calculation on production of He2+ ions inside the plasma ball reveals that reduced operating pressure and increased cathode area will help to generate He2+ ions with the layered-glow DC discharge.

  2. Corona Glow Discharge Plasma Treatment for Hidrophylicity Improvement of Polyester and Cotton Fabrics

    Science.gov (United States)

    Susan, A. I.; Widodo, M.; Nur, M.

    2017-07-01

    The effects of irradiation by a corona glow discharge plasma on hidrophylicity properties of polyester and cotton fabrics were investigated. We used a corona glow discharge plasma reactor with multiple points to plane electrodes, which was generated by a high voltage DC. Factors that affect the hidrophylicity properties were identified and evaluated as functions of irradiation parameters, which include duration of treatment, distance between electrodes, and bias voltage. It was readily observed from SEM examinations that plasma changed the surface morphology of both polyester and cotton fibers, giving result to an increased roughness to both of them. Results also showed that the hidrophylicityof polyester and cotton fabrics improved by the treatment, which is proportional to the time of treatment and voltage, but inversely proportional to the distance between electrodes. Time of treatment that provided the optimum enhancement of hidrophylicity for cotton is 15 minutes which improved the wetting time from 8.16 seconds to 1.26 seconds. For polyester, it took 15 minutes of irradiation time to improve the wetting time from 7340 seconds to 2905 seconds. The optimum distance between electrodes for both fabrics in this study was found to be 2 cm. Further analysis showed that the improved hidrophylicity properties is due to the creation of surface radicals by free radicals in the plasma leading to the formation of new water-attracting functional groups on the fiber surface.

  3. Dynamic model based on voltage transfer curve for pattern formation in dielectric barrier glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ben; He, Feng; Ouyang, Jiting, E-mail: jtouyang@bit.edu.cn [School of Physics, Beijing Institute of Technology, Beijing 100081 (China); Duan, Xiaoxi [Research Center of Laser Fusion, CAEP, Mianyang 621900 (China)

    2015-12-15

    Simulation work is very important for understanding the formation of self-organized discharge patterns. Previous works have witnessed different models derived from other systems for simulation of discharge pattern, but most of these models are complicated and time-consuming. In this paper, we introduce a convenient phenomenological dynamic model based on the basic dynamic process of glow discharge and the voltage transfer curve (VTC) to study the dielectric barrier glow discharge (DBGD) pattern. VTC is an important characteristic of DBGD, which plots the change of wall voltage after a discharge as a function of the initial total gap voltage. In the modeling, the combined effect of the discharge conditions is included in VTC, and the activation-inhibition effect is expressed by a spatial interaction term. Besides, the model reduces the dimensionality of the system by just considering the integration effect of current flow. All these greatly facilitate the construction of this model. Numerical simulations turn out to be in good accordance with our previous fluid modeling and experimental result.

  4. Determination of trace amounts of impurities in molybdenum by spark source and glow discharge mass spectrometry

    International Nuclear Information System (INIS)

    Saito, Morimasa

    1994-01-01

    For the determination of trace and ultra-trace amounts of impurities in high-purity molybdenum, spark source mass spectrometry and glow discharge mass spectrometry were studied. In spark source mass spectrometry using the metal probe method, the liquid-helium cryogenic pump was used in order to protect the surface of the samples from oxidation. The theoretical relative sensitivity factors (Mo=1) calculated from physical properties were used. The analytical results obtained for molybdenum tablet and high-purity molybdenum were in good agreement with those obtained by other methods (atomic absorption spectrometry and others). In glow discharge mass spectrometry, the relative sensitivity factors were calculated by using the results obtained by spark source mass spectrometry and atomic absorption spectrometry, and this method was applied to the determination of ultra-trace amounts of impurities in ultra high-purity molybdenum and gave the satisfactory results. The detection limits (2σ, n=10) in the integration time of 600 s for U and Th were 0.6 ppb and 0.3 ppb, and the values for Al, Si, Cr, Mn and Cu were in the range of 10 ppb to 0.5 ppb. (author)

  5. Fluorescent Glow

    Directory of Open Access Journals (Sweden)

    Micol Hutchison

    2014-10-01

    Full Text Available This narrative describes aspects of my semester teaching English as a Second Language in the city jail. I had expected to be able to draw grand conclusions about incarceration, inmates and policy, but instead I discovered that the inmates sitting in front of me were, above all else, simply students. The article also includes a digital story about the experience. The narrative is intended for those with interest in jail or prison education.

  6. Recent progress on the Los Alamos Aurora ICF [inertial confinement fusion] laser system

    International Nuclear Information System (INIS)

    Rosocha, L.A.; Blair, L.S.

    1987-01-01

    Aurora is the Los Alamos short-pulse, high-power, krypton-fluoride laser system. It serves as an end-to-end technology demonstration prototype for large-scale ultraviolet laser systems for short wavelength inertial confinement fusion (ICF) investigations. The system is designed to employ optical angular multiplexing and serial amplification by electron-beam-driven KrF laser amplifiers to deliver stacked, 248-nm, 5-ns duration multikilojoule laser pulses to ICF-relevant targets. This paper presents a summary of the Aurora system and a discussion of the progress achieved in the construction and integration of the laser system. We concentrate on the main features of the following major system components: front-end lasers, amplifier train, multiplexer, optical relay train, demultiplexer, and the associated optical alignment system. During the past year, two major construction and integration tasks have been accomplished. The first task is the demonstration of 96-beam multiplexing and amplified energy extraction, as evidenced by the integrated operation of the front end, the multiplexer (12-fold and 8-fold encoders), the optical relay train, and three electron-beam-driven amplifiers. The second task is the assembly and installation of the demultiplexer optical hardware, which consists of over 300 optical components ranging in size from several centimeters square to over a meter square. 13 refs., 13 figs

  7. Creation of visible artificial optical emissions in the aurora by high-power radio waves.

    Science.gov (United States)

    Pedersen, Todd R; Gerken, Elizabeth A

    2005-02-03

    Generation of artificial light in the sky by means of high-power radio waves interacting with the ionospheric plasma has been envisaged since the early days of radio exploration of the upper atmosphere, with proposed applications ranging from regional night-time street lighting to atmospheric measurements. Weak optical emissions have been produced for decades in such ionospheric 'heating' experiments, where they serve as key indicators of electron acceleration, thermal heating, and other effects of incompletely understood wave-particle interactions in the plasma under conditions difficult to replicate in the laboratory. The extremely low intensities produced previously have, however, required sensitive instrumentation for detection, preventing applications beyond scientific research. Here we report observations of radio-induced optical emissions bright enough to be seen by the naked eye, and produced not in the quiet mid-latitude ionosphere, but in the midst of a pulsating natural aurora. This may open the door to visual applications of ionospheric heating technology or provide a way to probe the dynamics of the natural aurora and magnetosphere.

  8. Tradición y tensión cultural en La trova de Aurora Venturini

    Directory of Open Access Journals (Sweden)

    Giselle Carolina Rodas

    2018-01-01

    Full Text Available En este artículo se propone un análisis hermenéutico del poemario La trova (1962, de la escritora argentina Aurora Venturini (1921-2015. Se trata de un libro significativo en el conjunto de su obra por ser signo del giro estético que se produjo en su proyecto creador durante la década del sesenta y que se evidenció en el pasaje de la poesía a la narrativa. La trova presenta un sujeto imaginario atravesado por las tensiones y oposiciones de diferentes rasgos culturales, cuya identidad se define en el diálogo con la tradición del medioevo. This article provides a hermeneutic study of the book of poetry La trova (1962, by the Argentinian writer Aurora Venturini (1921-2015. This is a significant book among her literary works, as it is a sign of the aesthetic turn that occurred in Venturini’s creative project during the sixties, which was evidenced in the passage from poetry to narrative. La trova presents a persona affected by the tensions and oppositions of different cultural features, whose identity is defined through the dialog with the medieval tradition.

  9. Integration of the Aurora KrF ICF laser system at Los Alamos

    International Nuclear Information System (INIS)

    Rosocha, L.A.; Blair, L.S.

    1988-01-01

    The Aurora laser system, under construction at the Los Alamos National Laboratory for the past few years, is now being integrated into a working system for examining the applicability of high-power KrF lasers to inertial confinement fusion (ICF). The design principles of the system have been described in detail in earlier publications and conferences. Multikilojoule 248-nm 5-ns duration laser pulses, which have been derived from angular-multiplexed electron-beam-driven KrF amplifiers, are to be delivered to ICF targets when the system is fully integrated. The authors describe the progress of the Aurora system toward the goal of delivering energy (MkJ/48 pulses stacked into one 5-ns pulse/200-μm spot) to ICF targets. Integrated performance to date of the front end optical multiplexer/demultiplexer e-beam-driven amplifiers and alignment hardware are discussed in particular. They have concentrated on the demonstration of system integration at a modest (--100-J) level of energy on-target (without the final amplifier stage). They discuss the amplifier gain measurements, the extraction of energy from a chain of three e-beam-driven machines, and progress toward the delivery of on-target energy

  10. Improved performance of the Aurora KrF/ICF laser system

    International Nuclear Information System (INIS)

    Jones, J.E.; Czuchlewski, S.J.; Turner, T.P.; Watt, R.G.; Thomas, S.J.; Netz, D.A.; Tallman, C.R.; Figueira, J.F.

    1990-01-01

    This paper reports on Aurora the Los Alamos National Laboratory short pulse high power krypton-fluoride laser system. It serves as an end-to-end technology demonstration prototype for large scale UV laser systems for short wavelength inertial confinement fusion (ICF) research. The system employs optical angular multiplexing and serial amplification by electron-beam driven KrF laser amplifiers. The 1-5-ns pulse of the Aurora front end is split into ninety-six beams which are angularly and temporally multiplexed to produce a 480-ns pulse train for amplification by four KrF laser amplifiers. The largest amplifier, the large aperture module (LAM), has a 1-m square aperture and a gain length of 2 m. In the present system configuration half (forty-eight) of the amplified pulses are demultiplexed using different optical path lengths and delivered simultaneously to target. The system has not been optimized, and several near term improvements are expected to result in significant increases in both delivered energy and target irradiance. Removing the twelve calorimeters from the lens plate and allowing forty-eight beams to go to target will increase delivered energy by 33%. Relatively minor modifications to the front end should result in a 30% increase in system output energy. Replacement of damaged optics will increase transmission into the preamplifier by at least 25%. New optics and reduction of retro-pulses will allow the preamplifier stage gain to be increased by 50%

  11. Diverse Electron and Ion Acceleration Characteristics Observed Over Jupiter's Main Aurora

    Science.gov (United States)

    Mauk, B. H.; Haggerty, D. K.; Paranicas, C.; Clark, G.; Kollmann, P.; Rymer, A. M.; Peachey, J. M.; Bolton, S. J.; Levin, S. M.; Adriani, A.; Allegrini, F.; Bagenal, F.; Bonfond, B.; Connerney, J. E. P.; Ebert, R. W.; Gladstone, G. R.; Kurth, W. S.; McComas, D. J.; Ranquist, D.; Valek, P.

    2018-02-01

    Two new Juno-observed particle features of Jupiter's main aurora demonstrate substantial diversity of processes generating Jupiter's mysterious auroral emissions. It was previously speculated that sometimes-observed potential-driven aurora (up to 400 kV) can turn into broadband stochastic acceleration (dominating at Jupiter) by means of instability. Here direct evidence for such a process is revealed with a "mono-energetic" electron inverted-V rising in energy to 200 keV, transforming into a region of broadband acceleration with downward energy fluxes tripling to 3,000 mW/m2, and then transforming back into a mono-energetic structure ramping down from 200 keV. But a second feature of interest observed nearby is unlikely to have operated in the same way. Here a downward accelerated proton inverted-V, with inferred potentials to 300-400 kV, occurred simultaneously with downward accelerated broadband electrons with downward energy fluxes as high as any observed ( 3,000 mW/m2). This latter feature has no known precedent with Earth auroral observations.

  12. Floristic Inventory of The Proposed Site for Tarsier Tourism Center in Villa Aurora, Bilar, Bohol, Philippines

    Directory of Open Access Journals (Sweden)

    Tomas D Reyes Jr

    2015-07-01

    Full Text Available The study assessed the present vegetation composition of the Proposed Site for the Tarsier Tourism Center (PTTC at Villa Aurora, Bilar, Bohol and performed a comparative analysis with the existing Tarsier Sanctuary (TS at Canapnapan, Corella, Bohol. The basis for comparison was the computed importance values, species richness, species dominance, and percent distribution of plants according to self-defined DBH classes. Results showed that both sites had very high species richness and evenness values. Common overstorey and understorey plant species found in both areas were katagpo (Psychotria sp., sagimsim (Syzygium brevistylum [C. B. Rob]Merr. and bagauak (Clerodendrum minahassae Teijsm. & Binn.. Apart from sagimsim (Syzygium brevistylum [C.B.Rob.] Merr., selaginella (Selaginella cuppresina Lin., and lunas (Lunasia amara Blanco were also common in the ground vegetation of both areas. Percent distribution of trees according to self-defined DBH classes revealed that PTTC had 87.55% of the total recorded plants with DBH measurements of 20 cm. Percent distribution of trees on these DBH ranges (especially on DBH class >20 cm indicated the presence of medium and large trees. The largest DBH measured in the PTTC was 70 cm while in TS was only 22 cm. The proposed 10-ha site in Villa Aurora, Bilar, is suited to be utilized as Tarsier Tourism Center. In case the proposed project is to be pursued, enclosure similar to what has been constructed in Canapnapan, Corella, Bohol, Philippines should also be established to prevent stray animals from predating the captive tarsiers.

  13. Phenotypic screening approaches to develop Aurora kinase inhibitors: Drug Discovery perspectives

    Directory of Open Access Journals (Sweden)

    Carlos eMarugán

    2016-01-01

    Full Text Available Targeting mitotic regulators as a strategy to fight cancer implies the development of drugs against key proteins such as Aurora A and B. Current drugs which target mitosis through a general mechanism of action (stabilization/destabilization of microtubules, have several side effects (neutropenia, alopecia, emesis. Pharmaceutical companies aim at avoiding these unwanted effects by generating improved and selective drugs that increase the quality of life of the patients. However, the development of these drugs is an ambitious task that involves testing thousands of compounds through biochemical and cell-based assays. In addition, molecules usually target complex biological processes, involving several proteins and different molecular pathways, further emphasizing the need for high-throughput screening techniques and multiplexing technologies in order to identify drugs with the desired phenotype.We will briefly describe two multiplexing technologies (high-content imaging, microarrays and flow cytometry and two key processes for drug discovery research (assay development and validation following our own published industry quality standards. We will further focus on high-content imaging as a useful tool for phenotypic screening and will provide a concrete example of high-content imaging assay to detect Aurora A or B selective inhibitors discriminating the off-target effects related to inhibition of other cell cycle or non-cell cycle key regulators. Finally, we will describe other assays that can help to characterize the in vitro pharmacology of the inhibitors.

  14. Environmental impact assessment - baseline noise survey and noise impact assessment for Aurora Mine

    International Nuclear Information System (INIS)

    Yee, S.

    1996-01-01

    A noise impact assessment was conducted at Syncrude's proposed Aurora Mine site to comply with Alberta Energy and Utilities Board (AEUB) Noise Control Directive ID 94-4. Noise assessments were conducted near a major noise source, i.e. the hydraulic and electric shovels. Noise levels at 50 meters away from the source varied from 72.3 to 79.7 dBA. The worst case noise level was 75 dBA measured at 100 meters away from a hydraulic shovel. This assessment was used to calculate the predicted design sound level from a noise source at the nearest or most impacted occupied dwelling. Two cabins located near the access road and along Kearl Lake respectively, were identified as the most impacted and nearest dwellings to the mine site. The predicted sound level at one cabin was 43 dBA, and 55 dBA at the other. Fort McKay was also assessed because it is the nearest community to the mine site. The sound level at Fort McKay was predicted to be 34 dBA. These results indicate that the sound level from Aurora Mine is not in compliance with the AEUB Noise Control Directive. Attenuation measures are required to reduce the noise to acceptable level at Cabin A and B. Predicted sound level at Fort McKay is lower than the permitted sound level

  15. Ndel1 suppresses ciliogenesis in proliferating cells by regulating the trichoplein-Aurora A pathway.

    Science.gov (United States)

    Inaba, Hironori; Goto, Hidemasa; Kasahara, Kousuke; Kumamoto, Kanako; Yonemura, Shigenobu; Inoko, Akihito; Yamano, Shotaro; Wanibuchi, Hideki; He, Dongwei; Goshima, Naoki; Kiyono, Tohru; Hirotsune, Shinji; Inagaki, Masaki

    2016-02-15

    Primary cilia protrude from the surface of quiescent cells and disassemble at cell cycle reentry. We previously showed that ciliary reassembly is suppressed by trichoplein-mediated Aurora A activation pathway in growing cells. Here, we report that Ndel1, a well-known modulator of dynein activity, localizes at the subdistal appendage of the mother centriole, which nucleates a primary cilium. In the presence of serum, Ndel1 depletion reduces trichoplein at the mother centriole and induces unscheduled primary cilia formation, which is reverted by forced trichoplein expression or coknockdown of KCTD17 (an E3 ligase component protein for trichoplein). Serum starvation induced transient Ndel1 degradation, subsequent to the disappearance of trichoplein at the mother centriole. Forced expression of Ndel1 suppressed trichoplein degradation and axonemal microtubule extension during ciliogenesis, similar to trichoplein induction or KCTD17 knockdown. Most importantly, the proportion of ciliated and quiescent cells was increased in the kidney tubular epithelia of newborn Ndel1-hypomorphic mice. Thus, Ndel1 acts as a novel upstream regulator of the trichoplein-Aurora A pathway to inhibit primary cilia assembly. © 2016 Inaba et al.

  16. New auroras on the roles of the Chromosomal Passenger Complex in cytokinesis: implications for cancer therapies

    Directory of Open Access Journals (Sweden)

    Pier Paolo eD'Avino

    2015-10-01

    Full Text Available The Chromosomal Passenger Complex (CPC, composed of a kinase component, Aurora B, the scaffolding subunit Inner Centromeric Protein (INCENP, Borealin, and Survivin, is a key regulator of cell division. It controls multiple events, from chromosome condensation in prophase to the final separation or abscission of the two daughter cells. The essential functions of the CPC during metaphase, however, have always hindered an accurate study of its role during cytokinesis. The recent development of small molecule inhibitors against Aurora B and the use of elegant technologies such as chemical genetics have offered new approaches to study the functions of the CPC at the end of cell division. Here we review the recent findings about the roles of the CPC in controlling the assembly of the cleavage furrow, central spindle and midbody. We will also discuss the crucial function of this complex in controlling abscission timing in order to prevent abscission when lagging chromatin is present at the cleavage site, thereby avoiding the formation of genetically abnormal daughter cells. Finally, we offer our perspective on how to exploit the potential therapeutic applications of inhibiting CPC activity during cytokinesis in cancer cells.

  17. Polarized electron sources

    Energy Technology Data Exchange (ETDEWEB)

    Prepost, R. [Univ. of Wisconsin, Madison, WI (United States)

    1994-12-01

    The fundamentals of polarized electron sources are described with particular application to the Stanford Linear Accelerator Center. The SLAC polarized electron source is based on the principle of polarized photoemission from Gallium Arsenide. Recent developments using epitaxially grown, strained Gallium Arsenide cathodes have made it possible to obtain electron polarization significantly in excess of the conventional 50% polarization limit. The basic principles for Gallium and Arsenide polarized photoemitters are reviewed, and the extension of the basic technique to strained cathode structures is described. Results from laboratory measurements of strained photocathodes as well as operational results from the SLAC polarized source are presented.

  18. 78 FR 23318 - Trust for Professional Managers and Aurora Investment Management L.L.C.; Notice of Application

    Science.gov (United States)

    2013-04-18

    ... subadvisory agreements (``Subadvisory Agreements'') with Chicago Fundamental Investment Partners, LLC, First... COMMISSION Trust for Professional Managers and Aurora Investment Management L.L.C.; Notice of Application... application under section 6(c) of the Investment Company Act of 1940 (``Act'') for an exemption from section...

  19. Lower-thermospheric wind fluctuations measured with an FPI during pulsating aurora at Tromsø, Norway

    Directory of Open Access Journals (Sweden)

    S. Oyama

    2010-10-01

    Full Text Available Simultaneous observations were conducted with a Fabry-Perot Interferometer (FPI at a wavelength of 557.7 nm, an all-sky camera at a wavelength of 557.7 nm, and the European Incoherent Scatter (EISCAT UHF radar during the Dynamics and Energetics of the Lower Thermosphere in Aurora 2 (DELTA-2 campaign in January 2009. This paper concentrated on two events during periods of pulsating aurora. The lower-thermospheric wind velocity measured with the FPI showed obvious fluctuations in both vertical and horizontal components. Of particular interest is that the location of the fluctuations was found in a darker area that appeared within the pulsating aurora. During the same time period, the EISCAT radar observed sporadic enhancements in the F-region backscatter echo power, which suggests the presence of low-energy electron (1 keV or lower precipitation coinciding with increase in amplitude of the electromagnetic wave (at the order of 10 Hz or higher. While we have not yet identified the dominant mechanism causing the fluctuations in FPI-derived wind velocity during the pulsating aurora, the frictional heating energy dissipated by the electric-field perturbations may be responsible for the increase in ionospheric thermal energy thus modifying the local wind dynamics in the lower thermosphere.

  20. The Aurora A-HP1γ pathway regulates gene expression and mitosis in cells from the sperm lineage.

    Science.gov (United States)

    Leonard, Phoebe H; Grzenda, Adrienne; Mathison, Angela; Morbeck, Dean E; Fredrickson, Jolene R; de Assuncao, Thiago M; Christensen, Trace; Salisbury, Jeffrey; Calvo, Ezequiel; Iovanna, Juan; Coddington, Charles C; Urrutia, Raul; Lomberk, Gwen

    2015-05-29

    HP1γ, a well-known regulator of gene expression, has been recently identified to be a target of Aurora A, a mitotic kinase which is important for both gametogenesis and embryogenesis. The purpose of this study was to define whether the Aurora A-HP1γ pathway supports cell division of gametes and/or early embryos, using western blot, immunofluorescence, immunohistochemistry, electron microscopy, shRNA-based knockdown, site-directed mutagenesis, and Affymetrix-based genome-wide expression profiles. We find that the form of HP1γ phosphorylated by Aurora A, P-Ser83 HP1γ, is a passenger protein, which localizes to the spermatozoa centriole and axoneme. In addition, disruption in this pathway causes centrosomal abnormalities and aberrations in cell division. Expression profiling of male germ cell lines demonstrates that HP1γ phosphorylation is critical for the regulation of mitosis-associated gene expression networks. In female gametes, we observe that P-Ser83-HP1γ is not present in meiotic centrosomes of M2 oocytes, but after syngamy, it becomes detectable during cleavage divisions, coinciding with early embryonic genome activation. These results support the idea that phosphorylation of HP1γ by Aurora A plays a role in the regulation of gene expression and mitotic cell division in cells from the sperm lineage and in early embryos. Combined, this data is relevant to better understanding the function of HP1γ in reproductive biology.

  1. Haspin kinase regulates microtubule-organizing center clustering and stability through Aurora kinase C in mouse oocytes

    Czech Academy of Sciences Publication Activity Database

    Balboula, A. Z.; Nguyen, A. L.; Gentilello, A. S.; Quartuccio, S. M.; Drutovič, Dávid; Šolc, Petr; Schindler, K.

    2016-01-01

    Roč. 129, č. 19 (2016), s. 3648-3660 ISSN 0021-9533 R&D Projects: GA MŠk(CZ) LO1609 Institutional support: RVO:67985904 Keywords : haspin * aurora kinase * spindle * MTOC * oocyte Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.431, year: 2016

  2. Account of nonlocal ionization by fast electrons in the fluid models of a direct current glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Rafatov, I. [Physics Department, Middle East Technical University, Ankara (Turkey); Bogdanov, E. A.; Kudryavtsev, A. A. [Saint Petersburg State University, St. Petersburg (Russian Federation)

    2012-09-15

    We developed and tested a simple hybrid model for a glow discharge, which incorporates nonlocal ionization by fast electrons into the 'simple' and 'extended' fluid frameworks. Calculations have been performed for an argon gas. Comparison with the experimental data as well as with the hybrid (particle) and fluid modelling results demonstated good applicability of the proposed model.

  3. GlowPhones: Designing for Proxemics Play with Low-Resolution Displays in Location-based Games

    DEFF Research Database (Denmark)

    Merritt, Timothy; Nielsen, Christine Linding; Jakobsen, Frederik Lund

    2017-01-01

    Location-based mobile games often utilize built-in sensors for supporting game experiences tied to the physical world, yet the visual user interface remains constrained to the small high-resolution screen. GlowPhones is a location-based mobile social game using low-resolution displays to augment ...

  4. Go with the Glow: An Investigation into a 1960s Art Object with Phosphorescent Paint and its Treatment Possibilities

    NARCIS (Netherlands)

    Jansen, E.; Smit, I.; Dikken, D.J.; Korterik, J.; Offerhaus, H.; Bailão, A.; Henriques, F.; Bidarra, A.

    2015-01-01

    This paper discusses phosphorescent or ‘glow in the dark’ paint and its problems, charac- teristics and treatment possibilities, while using an artwork without title (1968, RMT, En- schede) by IMI Giese as case study. To understand the problems that can occur with this little examined material, it

  5. QSAT: The Satellite for Polar Plasma Observation

    Science.gov (United States)

    Tsuruda, Yoshihiro; Fujimoto, Akiko; Kurahara, Naomi; Hanada, Toshiya; Yumoto, Kiyohumi; Cho, Mengu

    2009-04-01

    This paper introduces QSAT, the satellite for polar plasma observation. The QSAT project began in 2006 as an initiative by graduate students of Kyushu University, and has the potential to contribute greatly to IHY (International Heliophysical Year) by showing to the world the beauty, importance, and relevance of space science. The primary objectives of the QSAT mission are (1) to investigate plasma physics in the Earth’s aurora zone in order to better understand spacecraft charging, and (2) to conduct a comparison of the field-aligned current observed in orbit with ground-based observations. The QSAT project can provide education and research opportunities for students in an activity combining space sciences and satellite engineering. The QSAT satellite is designed to be launched in a piggyback fashion with the Japanese launch vehicle H-IIA. The spacecraft bus is being developed at the Department of Aeronautics and Astronautics of Kyushu University with collaboration of Fukuoka Institute of Technology. Regarding the payload instruments, the Space Environment Research Center of Kyushu University is developing the magnetometers, whereas the Laboratory of Spacecraft Environment Interaction Engineering of Kyushu Institute of Technology is developing the plasma probes. We aim to be ready for launch in 2009 or later.

  6. High expression of nuclear survivin and Aurora B predicts poor overall survival in patients with head and neck squamous cell cancer

    International Nuclear Information System (INIS)

    Erpolat, O.P.; Akmansu, M.; Gocun, P.U.; Karakus, E.; Akyol, G.

    2012-01-01

    Survivin is one of the apoptosis inhibitor proteins. Together with Aurora B, it also plays a role in regulating several aspects of mitosis. High expression of these markers is correlated with malignant behavior of various cancers and resistance to therapy. Our aim was to evaluate the prognostic role of these markers in head and neck cancers. We evaluated the expression of Aurora B and survivin in tissue specimens of 58 patients with head and neck squamous cell carcinoma using immunohistochemistry. Patients who showed high expression of cytoplasmic and nuclear survivin and Aurora B had significantly shorter overall survival (p = 0.036, p < 0.000, p = 0.032, respectively). In multivariate analysis, high expression of nuclear survivin was the only independent negative prognostic factor (p = 0.024). Moreover, it was found that high co-expression of nuclear survivin and Aurora B had a negative effect on survival in univariate (p < 0.000) and multivariate (p < 0.000) analyses. The negative prognostic values of high expression of Aurora B and high co-expression of nuclear survivin and Aurora B on survival were shown. These findings suggest that co-expression of nuclear survivin and Aurora B can be useful diagnostic markers and therapeutic targets for head and neck squamous cell carcinoma. However, further studies with a larger number of patients in a more homogeneous disease group are needed to confirm the conclusion.

  7. High expression of nuclear survivin and Aurora B predicts poor overall survival in patients with head and neck squamous cell cancer

    Energy Technology Data Exchange (ETDEWEB)

    Erpolat, O.P.; Akmansu, M. [Medical School of Gazi Univ., Besevler-Ankara (Turkey). Dept. of Radiation Oncology; Gocun, P.U.; Karakus, E.; Akyol, G. [Medical School of Gazi Univ., Besevler-Ankara (Turkey). Dept. of Pathology

    2012-03-15

    Survivin is one of the apoptosis inhibitor proteins. Together with Aurora B, it also plays a role in regulating several aspects of mitosis. High expression of these markers is correlated with malignant behavior of various cancers and resistance to therapy. Our aim was to evaluate the prognostic role of these markers in head and neck cancers. We evaluated the expression of Aurora B and survivin in tissue specimens of 58 patients with head and neck squamous cell carcinoma using immunohistochemistry. Patients who showed high expression of cytoplasmic and nuclear survivin and Aurora B had significantly shorter overall survival (p = 0.036, p < 0.000, p = 0.032, respectively). In multivariate analysis, high expression of nuclear survivin was the only independent negative prognostic factor (p = 0.024). Moreover, it was found that high co-expression of nuclear survivin and Aurora B had a negative effect on survival in univariate (p < 0.000) and multivariate (p < 0.000) analyses. The negative prognostic values of high expression of Aurora B and high co-expression of nuclear survivin and Aurora B on survival were shown. These findings suggest that co-expression of nuclear survivin and Aurora B can be useful diagnostic markers and therapeutic targets for head and neck squamous cell carcinoma. However, further studies with a larger number of patients in a more homogeneous disease group are needed to confirm the conclusion.

  8. Aurora kinase B is important for antiestrogen resistant cell growth and a potential biomarker for tamoxifen resistant breast cancer.

    Science.gov (United States)

    Larsen, Sarah L; Yde, Christina W; Laenkholm, Anne-Vibeke; Rasmussen, Birgitte B; Duun-Henriksen, Anne Katrine; Bak, Martin; Lykkesfeldt, Anne E; Kirkegaard, Tove

    2015-04-08

    Resistance to antiestrogen therapy is a major clinical challenge in the treatment of estrogen receptor α (ER)-positive breast cancer. The aim of the study was to explore the growth promoting pathways of antiestrogen resistant breast cancer cells to identify biomarkers and novel treatment targets. Antiestrogen sensitive and resistant T47D breast cancer cell lines were used as model systems. Parental and fulvestrant resistant cell lines were subjected to a kinase inhibitor library. Kinase inhibitors preferentially targeting growth of fulvestrant resistant cells were identified and the growth inhibitory effect verified by dose-response cell growth experiments. Protein expression and phosphorylation were investigated by western blot analysis. Cell cycle phase distribution and cell death were analyzed by flow cytometry. To evaluate Aurora kinase B as a biomarker for endocrine resistance, immunohistochemistry was performed on archival primary tumor tissue from breast cancer patients who have received adjuvant endocrine treatment with tamoxifen. The selective Aurora kinase B inhibitor barasertib was identified to preferentially inhibit growth of fulvestrant resistant T47D breast cancer cell lines. Compared with parental cells, phosphorylation of Aurora kinase B was higher in the fulvestrant resistant T47D cells. Barasertib induced degradation of Aurora kinase B, caused mitotic errors, and induced apoptotic cell death as measured by accumulation of SubG1 cells and PARP cleavage in the fulvestrant resistant cells. Barasertib also exerted preferential growth inhibition of tamoxifen resistant T47D cell lines. Finally, high percentage of Aurora kinase B positive tumor cells was significantly associated with reduced disease-free and overall survival in 261 ER-positive breast cancer patients, who have received tamoxifen as first-line adjuvant endocrine treatment. Our results indicate that Aurora kinase B is a driving factor for growth of antiestrogen resistant T47D breast

  9. Airglow & Aurora

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Both are quantized emissions resulting from excited atoms, ions and molecules in the upper atmosphere. Both are quantized emissions resulting from excited atoms, ions and molecules in the upper atmosphere. Airglow is a global phenomena whose excitation is ...

  10. Ozone Satellite Data Synergy and Combination with Non-satellite Data in the AURORA project

    Science.gov (United States)

    Cortesi, U.; Tirelli, C.; Arola, A.; Dragani, R.; Keppens, A.; Loenen, E.; Masini, A.; Tsiakos, , C.; van der A, R.; Verberne, K.

    2017-12-01

    The geostationary satellite constellation composed of TEMPO (North America), SENTINEL-4 (Europe) and GEMS (Asia) missions is a major instance of space component in the fundamentally new paradigm aimed at integrating information on air quality from a wide variety of sources. Space-borne data on tropospheric composition from new generation satellites have a growing impact in this context because of their unprecedented quantity and quality, while merging with non-satellite measurements and other types of auxiliary data via state-of-the-art modelling capabilities remains essential to fit the purpose of highly accurate information made readily available at high temporal and spatial resolution, both in analysis and forecast mode. Proper and effective implementation of this paradigm poses severe challenges to science, technology and applications that must be addressed in a closely interconnected manner to pave the way to high quality products and innovative services. Novel ideas and tools built on these three pillars are currently under investigation in the AURORA (Advanced Ultraviolet Radiation and Ozone Retrieval for Applications) Horizon 2020 project of the European Commission. The primary goal of the project is the proof of concept of a synergistic approach to the exploitation of Sentinel-4 and -5 Ozone measurements in the UV, Visible and Thermal Infrared based on the combination of an innovative data fusion method and assimilation models. The scientific objective shares the same level of priority with the technological effort to realize a prototype data processor capable to manage the full data processing chain and with the development of two downstream applications for demonstration purposes. The presentation offers a first insight in mid-term results of the project, which is mostly based on the use of synthetic data from the atmospheric Sentinels. Specific focus is given to the role of satellite data synergy in integrated systems for air quality monitoring, in

  11. Elemental analysis of geological materials by a glow discharge mass spectrometry

    Directory of Open Access Journals (Sweden)

    A. I. Hanchuk

    2014-01-01

    Full Text Available Advances of elemental analysis in geology are defined by the development and improvement ofphysical, instrumental methods of chemical analysis. New instrumental methods - emission spectrometry and mass spectrometry with inductively coupled plasma (ICP sources are the most popular in the area of elemental analysis in recent years. These methods have a very high sensitivity and wide range of elements analyzed (up to 70 items at a time. Both of these methods have been developed and demonstrate their high analytical performance only when analyzing liquids. Consequently, when using these methods in geology, solid samples must be completely transferred into liquid. This complicates the analysis, especially in the analysis of sparingly soluble objects. In some cases, analyzed geological objects are generally insoluble in acids and other solvents (e.g. such as black shales are not dissolved till the end in any acids. Naturally, there is a need to develop an analytical method, wherein the step of dissolution of the sample can be avoided. Such instrumental methods exist but are not used because of low sensitivity. Method of glow discharge mass spectrometry has the greatest potential today, but its use is hampered by lack of a recognized certified ion source capable of converting analyzed (in most cases - not conductive geological sample into low-temperature plasma. In this paper, the glow discharge source on the basis of the hollow cathode is used as an external source. The hollow cathode has been long and successfully used in analytical practice in emission spectral analysis. However, for use in mass spectrometry, its design has been considerably modified. The analyzed sample, which was formerly in the form of powder or fine particles located at the bottom of the hollow cathode, in a new cathode is installed as a rod along the axis of the inner cathode cavity - it is the emitter of sputtered neutral particles. Hollow cathode source is set on the high

  12. Surface modification with a remote atmospheric pressure plasma: dc glow discharge and surface streamer regime

    International Nuclear Information System (INIS)

    Temmerman, Eef; Akishev, Yuri; Trushkin, Nikolay; Leys, Christophe; Verschuren, Jo

    2005-01-01

    A remote atmospheric pressure discharge working with ambient air is used for the near room temperature treatment of polymer foils and textiles of varying thickness. The envisaged plasma effect is an increase in the surface energy of the treated material, leading, e.g., to a better wettability or adhesion. Changes in wettability are examined by measuring the contact angle or the liquid absorptive capacity. Two regimes of the remote atmospheric pressure discharge are investigated: the glow regime and the streamer regime. These regimes differ mainly in power density and in the details of the electrode design. The results show that this kind of discharge makes up a convenient non-thermal plasma source to be integrated into a treatment installation working at atmospheric pressure

  13. Ultra-low density metallic foams synthesized by contact glow discharge electrolysis (CGDE) for laser experiments

    Science.gov (United States)

    Rocher, Sandrine; Botrel, Ronan; Durut, Frédéric; Chicanne, Cédric; Theobald, Marc; Vignal, Vincent

    2018-02-01

    The goal of this work is to realize metallic foams synthesized by contact glow discharge electrolysis with specific characteristics. In this paper, we show the results of our studies, consisting in investigating parameters that influence the foams characteristics. Thus, the morphology of metallic foams is examined through scanning electron microscopy (SEM) observations with the acid nature. Moreover, the evolution of the mass and the volume of metallic foams with two experimental parameters (overvoltage and gold concentration) is also investigated. The acid nature affects the foams microscopic structure highlighted by the SEM observations, but for now no valid explanation to this behaviour was found. We prove that the mass deposited on the electrode is dependent on the ionic salt concentration, whereas the overvoltage only affects the foam overall density. Contribution to the topical issue "Plasma Sources and Plasma Processes (PSPP)", edited by Luis Lemos Alves, Thierry Belmonte and Tiberiu Minea.

  14. Control of discharge conditions to reduce hydrogen content in low Z films produced with DC glow

    Energy Technology Data Exchange (ETDEWEB)

    Natsir, M.; Sagara, A.; Tsuzuki, K.; Tsuchiya, B.; Hasegawa, Y.; Motojima, O.

    1995-09-01

    Boronization at near room temperature has been performed in plasma processing teststand (PPT) by using a 5 % diborane gases B{sub 2}H{sub 6} in He on electrically floating or unfloating Al samples under various conditions on DC glow discharge power or total gas pressure. The hydrogen concentration was analyzed by using elastic recoil detection method (ERD) and a new modified normalizing technique with Rutherford back scattering (RBS). Results showed that a high growth rate of film formation and floating surface were effective in reducing hydrogen concentration in B films. This result was in good agreement with earlier measurements of H with flash filament (FF) desorption method. In particular the H/B ratio was reduced by decreasing ions but increasing radicals for B film formation. (author).

  15. Periodic long-range transport in a large volume dc glow discharge dusty plasma

    International Nuclear Information System (INIS)

    Thomas, Edward Jr.; Amatucci, William E.; Compton, Christopher; Christy, Brian; Jackson, Jon David

    2003-01-01

    In an earlier paper, the authors reported on observations of a variety of particle transport phenomena observed in DUPLEX--the DUsty PLasma EXperiment at the Naval Research Laboratory [E. Thomas, Jr., W. E. Amatucci, C. Compton, and B. Christy, Phys. Plasmas 9, 3154 (2002)]. DUPLEX is a large, transparent polycarbonate cylinder that is 40 cm in radius and 80 cm in height. dc glow discharge argon plasmas are generated in DUPLEX. In this paper, the authors expand upon one particular feature of particle transport in DUPLEX, the long-range (i.e., greater than 15 cm), periodic (T∼2.5 min) transport of suspended alumina particles through the plasma. A detailed description of this particle motion through the plasma is presented. Finally, a qualitative model describing the phenomena that lead to this transport is also given

  16. Spatially Resolved Gas Temperature Measurements in an Atmospheric Pressure DC Glow Microdischarge with Raman Scattering

    Science.gov (United States)

    Belostotskiy, S.; Wang, Q.; Donnelly, V.; Economou, D.; Sadeghi, N.

    2006-10-01

    Spatially resolved rotational Raman spectroscopy of ground state nitrogen N2(X^1σg^+) was used to measure the gas temperature (Tg) in a nitrogen dc glow microdischarge (gap between electrodes d˜500 μm). An original backscattering, confocal optical system was developed for collecting Raman spectra. Stray laser light and Raleigh scattering were blocked by using a triple grating monochromator and spatial filters, designed specifically for these experiments. The optical system provided a spatial resolution of electrodes, Tg increased linearly with jd, reaching 500 K at 1000 mA/cm^2 jd for a pressure of 720 Torr. Spatially resolved gas temperature measurements will also be presented and discussed in combination with a mathematical model for gas heating in the microplasma. This work is supported by DoE/NSF.

  17. Reduction of hydrogen content in boron film by controlling glow discharge conditions

    Science.gov (United States)

    Natsir, M.; Sagara, A.; Motojima, O.

    1995-04-01

    Reducing the hydrogen content in boron films produced with DC glow discharge was first investigated at room temperature in plasma processing teststand (PPT) by measuring dependences on B 10H 14 flow rate, mixing ratio in helium, discharge power, and total pressure. The experimental condition during boronization was monitored using Langmuir probe. The hydrogen concentration was analyzed by using an in situflash-filament desorption method. Results show that a high growth rate of film formation and high pumping speed are effective in reducing hydrogen concentration. This new finding is applicable to reduce hydrogen recycling from boronized walls in present day plasma machines which cannot use high temperature baking over 100°C.

  18. Compositional characterisation of rare earth magnet materials by glow discharge quadrupole mass spectrometry

    International Nuclear Information System (INIS)

    Reddy, M.A.; Shekhar, R.; Kumar, Sunil Jai

    2014-01-01

    In this paper, glow discharge quadrupole mass spectrometric (GD-QMS) studies on Sm-Pr-Co compound magnetic materials are reported. The composition of these magnetic materials produced from different manufacturing routes (imported, indigenous) was determined. The results are compared with the results obtained by an alternative analytic technique, inductively coupled plasma atomic emission spectrometry (ICP-AES), after complete dissolution of the material in the appropriate acids. For perfectly homogeneous material both the wet chemical method and direct solid analysis method should give the same result. A close examination of both the results indicates that for imported materials the values obtained by wet chemical method and direct solid method are in close agreement. This indicates that the imported (solid) material is highly homogeneous. For indigenous materials, it shows a large difference in the values of Co and Sm. This reveals that the solid material prepared is not as homogenous as the imported materials

  19. Child-Langmuir law for cathode sheath of glow discharge in CO2

    International Nuclear Information System (INIS)

    Lisovskiy, V.A.; Krol, H.H.; Osmayev, R.O.; Yegorenkov, V.D.

    2016-01-01

    This work is devoted to the determination of the law that may be applicable to the description of the cathode sheath in CO 2 . To this end three versions of the Child-Langmuir law have been considered - a collision free one (for the ions moving through a cathode sheath without collisions with gas molecules) as well as two collision- related versions - one for a constant mean free path of positive ions and one for a constant mobility of positive ions. The current-voltage characteristics and the cathode sheath thickness of the glow discharge in CO 2 have been simultaneously measured in the pressure range from 0.05 to 1 Torr and with the discharge current values up to 80 mA. In the whole range of the discharge conditions we have studied the cathode sheath characteristics are found to obey correctly only to the Child-Langmuir law version with a constant ion mobility.

  20. Surface enrichment with chrome and nitriding of IF steel under an abnormal glow discharge

    International Nuclear Information System (INIS)

    Meira, S.R.; Borges, P.C.; Bernardelli, E.A.

    2014-01-01

    The objective of this work is to evaluate the influence of surface enrichment of IF steel with chrome, and nitriding, the formation of the nitrided layer. Thus, IF steel samples were subjected to surface enrichment process, using 409 stainless steel as a target for sputtering, followed by plasma nitriding, both under a dc abnormal glow discharge. The enrichment treatment was operated at 1200 ° C for 3h. The nitriding treatment was operated at 510 ° C for 2 h. The influence of the treatments on the layers formed was studied through optical microscopy (OM), scan electron microscopy (SEM), X-ray diffraction (XRD) and Vickers microindentation. The results show that the enrichment is effective to enrich the IF surface, furthermore, improves the characteristics of nitriding, comparing nitriding samples to nitriding and enriched, was observed needles of nitrides, as well as a higher hardness, which is associated with the nitrides of chrome, on the nitriding and enriched samples. (author)

  1. Synthesis of Biodiesel from Crude Palm Oil by Using Contact Glow Discharge Electrolysis

    Science.gov (United States)

    Saksono, Nelson; Aditya Siswosoebrotho, Danar; Pranata, Jeremia J. C.; Bismo, Setijo

    2018-03-01

    This research has evaluated the use of Contact Glow Discharge Electrolysis method in the synthesis of biodiesel. The purpose of this research is to get the synthesis process and biodiesel product. The solution used is the mix of Crude Palm Oil and methanol with molar ratio of 1:24, and catalyst of NaOH and KOH with variation of concentration 0.5% - 1.5%-wt. The result shows that the biodiesel can be made from transesterification reaction that may be initiated by radical methoxide. The use of electrolyte KOH is better than NaOH based on the yield of biodiesel and the energy consumption. The optimum yield reaches 97%, at the synthesis for 30 minutes with the use of KOH 1%-wt with the energy consumption of 1.32 kJ/mL.

  2. Plasma sheath physics and dose uniformity in enhanced glow discharge plasma immersion ion implantation and deposition

    International Nuclear Information System (INIS)

    Li Liuhe; Li Jianhui; Kwok, Dixon T. K.; Chu, Paul K.; Wang Zhuo

    2009-01-01

    Based on the multiple-grid particle-in-cell code, an advanced simulation model is established to study the sheath physics and dose uniformity along the sample stage in order to provide the theoretical basis for further improvement of enhanced glow discharge plasma immersion ion implantation and deposition. At t=7.0 μs, the expansion of the sheath in the horizontal direction is hindered by the dielectric cage. The electron focusing effect is demonstrated by this model. Most of the ions at the inside wall of the cage are implanted into the edge of the sample stage and a relatively uniform ion fluence distribution with a large peak is observed at the end. Compared to the results obtained from the previous model, a higher implant fluence and larger area of uniformity are disclosed.

  3. Technology of Glow Discharge Plasma to Improve Color Intensity on Polyester Fabric

    International Nuclear Information System (INIS)

    Kaelani, Zubaidi A.

    2000-01-01

    The surface modification have been studied onto polyester fiber toimprove color intensity of the dyed fabrics. The modifications carried byetching using glow discharge plasma under condition of 0.04 Torr, using 10Watt at 13.56 MHz. Both surface of original and modified fibers were analyzedby means of scanning electron microscope (SEM), and then both of fibers weredyed with disperse dyes and measured using color measurement apparatus tocompare the color shading, color intensity, and the brightness of the fibers.The color shading of modified fibers have small difference of original fiber,and the color intensity of modified fibers have much higher than originalfibers, while the brightness of the modified fibers tend to decrease. By themeasurements, can be concluded that the surface modifications by glowdischarge plasma are able to improve color deepness of the fabrics, and haveanother advantageous to the character of fabrics. (author)

  4. Thermal degradation process of poly (alpha-methylstyrene) microspheres coated with glow discharge polymer

    International Nuclear Information System (INIS)

    Zhang Zhanwen; Huang Yong; Tang Yongjian; Li Bo; Chen Sufen; He Zhibing

    2009-01-01

    Glow discharge polymer (GDP) shell was made by the decomposable mandrel technique using poly(alpha-methylstyrene) (PAMS) mandrel. The PAMS degradation rate and the GDP shell surface morphology at different equilibrium temperatures were investigated. Degradation rate was calculated from weight variation of PAMS before and after pyrolysis process. Experiment results indicate that the degradation rate decreases at the fixed equilibrium temperature and graded temperature can improve the rate. The degradation process has an effect on the GDP shell properties. The PAMS doesn't molten to flow liquid during degradation. But the degradation can reduce surface finish of GDP coatings. The GDP shell deffects are the result of the PAMS degradiation process. (authors)

  5. Surface modification by preparation of buffer zone in glow-discharge plasma

    International Nuclear Information System (INIS)

    Cho, D.L.

    1986-01-01

    Reactive species, energetic particles, and uv radiation in the plasma created by a glow discharge strongly interact with solid surfaces under the influence of the plasma. As a result of the strong interaction, various physical and chemical reactions, unique and advantageous for the surface modification of solid materials, occur on the solid surfaces. The surface modification is carried out through formation of a thin buffering layer on the solid surface. The preparation of a buffer zone on solid surfaces for surface modification is described. Two kinds of a buffer zone are prepared by plasma polymerization, or simultaneous sputter deposition of electrode material with plasma polymerization: a transitional buffer zone and a graded buffer zone. Important factors for preparation of the buffer zone (pre-conditioning of a substrate surface, thin-film deposition, post-treatment of the film, magnetron discharge, energy input, geometry of a substrate and a plasma) are discussed

  6. Isotopic abundance measurements on solid nuclear-type samples by glow discharge mass spectrometry.

    Science.gov (United States)

    Betti, M; Rasmussen, G; Koch, L

    1996-07-01

    A double-focusing Glow Discharge Mass Spectrometer (GDMS) installed in a glovebox for nuclear sample screening has been employed for isotopic measurements. Isotopic compositions of zirconium, silicon, lithium, boron, uranium and plutonium which are elements of nuclear concern have been determined. Interferences arising from the matrix sample and the discharge gas (Ar) for each of these elements are discussed. The GDMS results are compared with those from Thermal Ionization Mass Spectrometry (TIMS). For boron and lithium at microg/g-ng/g levels, the two methods gave results in good agreement. In samples containing uranium the isotopic composition obtained by GDMS was in agreement with those from TIMS independently of the enrichment. Attempts for the determination of plutonium isotopic composition were also made. In this case, due to the interferences of uranium at mass 238 and americium at mass 241, the GDMS raw data are complementary with those values obtained from physical non-destructive techniques.

  7. Raman spectra of amorphous silicon thin films deposited by glow discharge

    International Nuclear Information System (INIS)

    Bustarret, E.; Alvarez, F.; Brenzikofer, R.; Vilche Pena, A.; Chambouleyron, I.

    1983-01-01

    The local disorder present in films of a-Si:H and a-Si sub(x) N 1 - sub(x):H has been studied through first order Raman spectroscopy, using the 5145A line of an Argon laser in a backscattering geometry at room temperature. This allowed us to compare thin films deposited in two different reactors where the capacitively coupled glow-discharge was produced either in a 'cross field' or a 'parallel field' geometry. Gaseous mixtures of SiH 4 , N 2 , He and Ar have been used in both cases. The systematic variation of the preparation parameters leads to a whole class of 'alloys' including partially micro-crystallized films. (Author) [pt

  8. Nonlinear time-series analysis of current signal in cathodic contact glow discharge electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Allagui, Anis, E-mail: aallagui@sharjah.ac.ae; Abdelkareem, Mohammad Ali [Department of Sustainable and Renewable Energy Engineering, University of Sharjah, PO Box 27272, Sharjah (United Arab Emirates); Rojas, Andrea Espinel [Institut de Recherche en Communications et Cybernétique de Nantes, Ecole Centrale de Nantes, 44300 Nantes (France); Bonny, Talal; Elwakil, Ahmed S. [Department of Electrical and Computer Engineering, University of Sharjah, PO Box 27272, Sharjah (United Arab Emirates)

    2016-05-28

    In the standard two-electrode configuration employed in electrolytic process, when the control dc voltage is brought to a critical value, the system undergoes a transition from conventional electrolysis to contact glow discharge electrolysis (CGDE), which has also been referred to as liquid-submerged micro-plasma, glow discharge plasma electrolysis, electrode effect, electrolytic plasma, etc. The light-emitting process is associated with the development of an irregular and erratic current time-series which has been arbitrarily labelled as “random,” and thus dissuaded further research in this direction. Here, we examine the current time-series signals measured in cathodic CGDE configuration in a concentrated KOH solution at different dc bias voltages greater than the critical voltage. We show that the signals are, in fact, not random according to the NIST SP. 800-22 test suite definition. We also demonstrate that post-processing low-pass filtered sequences requires less time than the native as-measured sequences, suggesting a superposition of low frequency chaotic fluctuations and high frequency behaviors (which may be produced by more than one possible source of entropy). Using an array of nonlinear time-series analyses for dynamical systems, i.e., the computation of largest Lyapunov exponents and correlation dimensions, and re-construction of phase portraits, we found that low-pass filtered datasets undergo a transition from quasi-periodic to chaotic to quasi-hyper-chaotic behavior, and back again to chaos when the voltage controlling-parameter is increased. The high frequency part of the signals is discussed in terms of highly nonlinear turbulent motion developed around the working electrode.

  9. Nonlinear time-series analysis of current signal in cathodic contact glow discharge electrolysis

    International Nuclear Information System (INIS)

    Allagui, Anis; Abdelkareem, Mohammad Ali; Rojas, Andrea Espinel; Bonny, Talal; Elwakil, Ahmed S.

    2016-01-01

    In the standard two-electrode configuration employed in electrolytic process, when the control dc voltage is brought to a critical value, the system undergoes a transition from conventional electrolysis to contact glow discharge electrolysis (CGDE), which has also been referred to as liquid-submerged micro-plasma, glow discharge plasma electrolysis, electrode effect, electrolytic plasma, etc. The light-emitting process is associated with the development of an irregular and erratic current time-series which has been arbitrarily labelled as “random,” and thus dissuaded further research in this direction. Here, we examine the current time-series signals measured in cathodic CGDE configuration in a concentrated KOH solution at different dc bias voltages greater than the critical voltage. We show that the signals are, in fact, not random according to the NIST SP. 800-22 test suite definition. We also demonstrate that post-processing low-pass filtered sequences requires less time than the native as-measured sequences, suggesting a superposition of low frequency chaotic fluctuations and high frequency behaviors (which may be produced by more than one possible source of entropy). Using an array of nonlinear time-series analyses for dynamical systems, i.e., the computation of largest Lyapunov exponents and correlation dimensions, and re-construction of phase portraits, we found that low-pass filtered datasets undergo a transition from quasi-periodic to chaotic to quasi-hyper-chaotic behavior, and back again to chaos when the voltage controlling-parameter is increased. The high frequency part of the signals is discussed in terms of highly nonlinear turbulent motion developed around the working electrode.

  10. Aurora project: optical design for a kilojoule class KrF laser

    International Nuclear Information System (INIS)

    Hanlon, J.; McLeod, J.; Sollid, J.E.; Horn, W. III; Carmichael, R.; Kortegaard, B.; Woodfin, G.; Rosocha, L.

    1985-01-01

    Aurora is a 248-nm, 10-kilojoule laser system being built at Los Alamos National Laboratory to demonstrate the feasibility of large KrF laser systems for laser fusion. It was designed as a test bed to demonstrate: (1) efficiet energy extraction at 248 nm; (2) an angularly multiplexed optical system that is scaleable to large system designs; (3) the control of parasitics and ASE (amplified spontaneous emission); (4) long path pulse propagation at uv wavelengths; (5) alignment systems for multibeam systems; and (6) new or novel approaches to optical hardware that can lead to cost reduction on large systems. In this paper only issues pertinent to the optical system are addressed. First, a description of the entire system is given. The design constraints on the optical system are explained, concurrent with a discussion of the final design. This is followed by a very brief discussion of coatings; in particular, the use of sol-gels for antireflection coatings is presented

  11. The Ski Protein is Involved in the Transformation Pathway of Aurora Kinase A.

    Science.gov (United States)

    Rivas, Solange; Armisén, Ricardo; Rojas, Diego A; Maldonado, Edio; Huerta, Hernán; Tapia, Julio C; Espinoza, Jaime; Colombo, Alicia; Michea, Luis; Hayman, Michael J; Marcelain, Katherine

    2016-02-01

    Oncogenic kinase Aurora A (AURKA) has been found to be overexpresed in several tumors including colorectal, breast, and hematological cancers. Overexpression of AURKA induces centrosome amplification and aneuploidy and it is related with cancer progression and poor prognosis. Here we show that AURKA phosphorylates in vitro the transcripcional co-repressor Ski on aminoacids Ser326 and Ser383. Phosphorylations on these aminoacids decreased Ski protein half-life. Reduced levels of Ski resulted in centrosomes amplification and multipolar spindles formation, same as AURKA overexpressing cells. Importantly, overexpression of Ski wild type, but not S326D and S383D mutants inhibited centrosome amplification and cellular transformation induced by AURKA. Altogether, these results suggest that the Ski protein is a target in the transformation pathway mediated by the AURKA oncogene. © 2015 Wiley Periodicals, Inc.

  12. New records of the Cryphonectriaceae from southern Africa including Latruncellus aurorae gen. sp. nov.

    Science.gov (United States)

    Vermeulen, Marcele; Gryzenhout, Marieka; Wingfield, Michael J; Roux, Jolanda

    2011-01-01

    The Cryphonectriaceae accommodates some of the world's most important tree pathogens, including four genera known from native and introduced Myrtales in Africa. Surveys in the past 3 y in southern Africa have led to the discovery of cankers with fruiting structures resembling those of the Cryphonectriaceae on trees in the Myrtales in Namibia, South Africa, Swaziland and Zambia. These fungi were identified with morphological characteristics and DNA sequence data. For the first time we report Chrysoporthe austroafricana from Namibia and on Syzygium guineense and Holocryphia eucalypti in Swaziland on a Eucalyptus grandis clone. The host and geographic ranges of Celoporthe dispersa are expanded to include S. legatti in South Africa and S. guineense in Zambia. In addition a monotypic genus, Latruncellus aurorae gen. sp. nov., is described from Galpinia transvaalica (Lythraceae, Myrtales) in Swaziland. The present and other recent studies clearly emphasize the limited understanding of the diversity and distribution of fungi in the Cryphonectriaceae in Africa.

  13. Aurora kinase A is essential for correct chromosome segregation in mouse zygote.

    Science.gov (United States)

    Kovarikova, Veronika; Burkus, Jan; Rehak, Pavol; Brzakova, Adela; Solc, Petr; Baran, Vladimir

    2016-06-01

    Aurora-A kinase (AURKA), a member of the serine/threonine protein kinase family, is involved in multiple steps of mitotic progression. It regulates centrosome maturation, mitotic spindle formation, and cytokinesis. While studied extensively in somatic cells, little information is known about AURKA in the early cleavage mouse embryo with respect to acentrosomal spindle assembly. In vitro experiments in which AURKA was inactivated with specific inhibitor MLN8237 during the early stages of embryogenesis documented gradual arrest in the cleavage ability of the mouse embryo. In the AURKA-inhibited 1-cell embryos, spindle formation and anaphase onset were delayed and chromosome segregation was defective. AURKA inhibition increased apoptosis during early embryonic development. In conclusion these data suggest that AURKA is essential for the correct chromosome segregation in the first mitosis as a prerequisite for normal later development after first cleavage.

  14. Plant Aurora kinases play a role in maintenance of primary meristems and control of endoreduplication

    Czech Academy of Sciences Publication Activity Database

    Petrovská, Beáta; Cenklová, Věra; Pochylová, Žaneta; Kourová, Hana; Doskočilová, Anna; Plíhal, Ondřej; Binarová, Lenka; Binarová, Pavla

    2012-01-01

    Roč. 193, č. 3 (2012), s. 590-604 ISSN 0028-646X R&D Projects: GA ČR(CZ) GA204/07/1169; GA ČR GP204/09/P155; GA ČR(CZ) GD204/09/H084; GA MŠk(CZ) LC06034; GA MŠk LC545; GA AV ČR IAA500200719 Grant - others:GA MŠk(CZ) ED0007/01/01 Program:ED Institutional research plan: CEZ:AV0Z50380511; CEZ:AV0Z50200510 Keywords : Arabidopsis thaliana * AtTPX2 (targeting protein for Xklp2) * Aurora kinases Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 6.736, year: 2012

  15. GPS Signal Corruption by the Discrete Aurora: Precise Measurements From the Mahali Experiment

    Science.gov (United States)

    Semeter, Joshua; Mrak, Sebastijan; Hirsch, Michael; Swoboda, John; Akbari, Hassan; Starr, Gregory; Hampton, Don; Erickson, Philip; Lind, Frank; Coster, Anthea; Pankratius, Victor

    2017-10-01

    Measurements from a dense network of GPS receivers have been used to clarify the relationship between substorm auroras and GPS signal corruption as manifested by loss of lock on the received signal. A network of nine receivers was deployed along roadways near the Poker Flat Research Range in central Alaska, with receiver spacing between 15 and 30 km. Instances of large-amplitude phase fluctuations and signal loss of lock were registered in space and time with auroral forms associated with a sequence of westward traveling surges associated with a substorm onset over central Canada. The following conclusions were obtained: (1) The signal corruption originated in the ionospheric E region, between 100 and 150 km altitude, and (2) the GPS links suffering loss of lock were confined to a narrow band (<20 km wide) along the trailing edge of the moving auroral forms. The results are discussed in the context of mechanisms typically cited to account for GPS phase scintillation by auroral processes.

  16. Geographical Income Polarization

    DEFF Research Database (Denmark)

    Azhar, Hussain; Jonassen, Anders Bruun

    inter municipal income inequality. Counter factual simulations show that rising property prices to a large part explain the rise in polarization. One side-effect of polarization is tendencies towards a parallel polarization of residence location patterns, where low skilled individuals tend to live......In this paper we estimate the degree, composition and development of geographical income polarization based on data at the individual and municipal level in Denmark from 1984 to 2002. Rising income polarization is reconfirmed when applying new polarization measures, the driving force being greater...

  17. Aurora-A Expression Is Independently Associated with Chromosomal Instability in Colorectal Cancer

    Directory of Open Access Journals (Sweden)

    Yoshifumi Baba

    2009-05-01

    Full Text Available AURKA (the official symbol for Aurora-A, STK15, or BTAK regulates the function of centrosomes, spindles, and kinetochores for proper mitotic progression. AURKA overexpression is observed in various cancers including colon cancer, and a link between AURKA and chromosomal instability (CIN has been proposed. However, no study has comprehensively examined AURKA expression in relation to CIN or prognosis using a large number of tumors. Using 517 colorectal cancers in two prospective cohort studies, we detected AURKA overexpression (by immunohistochemistry in 98 tumors (19%. We assessed other molecular events including loss of heterozygosity (LOH in 2p, 5q, 17q, and 18q, the CpG island methylation phenotype (CIMP, and microsatellite instability (MSI. Prognostic significance of AURKA was evaluated by Cox regression and Kaplan-Meier method. In both univariate and multivariate logistic regressions, AURKA overexpression was significantly associated with CIN (defined as the presence of LOH in any of the chromosomal segments; multivariate odds ratio, 2.97; 95% confidence interval, 1.40–6.29; P = .0045. In multivariate analysis, AURKA was associated with cyclin D1 expression (P = .010 and inversely with PIK3CA mutation (P=.014, fatty acid synthase expression (P=.028, and family history of colorectal cancer (P = .050, but not with sex, age, body mass index, tumor location, stage, CIMP, MSI, KRAS, BRAF, BMI, LINE-1 hypomethylation, p53, p21, β-catenin, or cyclooxygenase 2. AURKA was not significantly associated with clinical outcome or survival. In conclusion, AURKA overexpression is independently associated with CIN in colorectal cancer, supporting a potential role of Aurora kinase-A in colorectal carcinogenesis through genomic instability (rather than epigenomic instability.

  18. MATHEMATICAL MODEL OF AUTOMATIC FLIGHT OF POLIKOPTER UAV NAU PKF "AURORA"

    Directory of Open Access Journals (Sweden)

    Wang Bo

    2016-12-01

    Full Text Available Purpose: Development of mathematical and experimental models of polikopter UAV NAU PKF "Aurora" of oktakopter scheme for experimental flights in manual, semi-automatic and unmanned mode.                  Methods: 14/03/2016 - 21/03/2016 held a serіe of experiental flights (10 flights of 10 rats on altitude 700 meters on polіkopter (oktakopter NAU PKF "Aurora" in germetic kabіn with the study of his somatic,  nevrologіcal status after the flight. Flights also carried out with experimental animals on board for such a safety assessment. Results: The obtained logs of 'black box' of the autopilot indicate very small (almost invisible fluctuations in pitch, roll and yaw during the flight, minor variations on altitude during almost stationary hovering of polikopter at different altitudes, and fully adequate to movements and maneuvers of aircraft vibrations and parameters of these sensors. Discussion: In the course of these studies demonstrated experimentally the possibility of completely safe flight of the mammals (rats on polikopter vehicle, even in the open cockpit. With appropriate refinement possible in the future to raise the issue of the development and construction of passenger polikopter flyers for totally safe air transportation of people [6,7,8]. In terms of adverse mechanical effects on the human body (acceleration overload fluctuations, vibrations polikopter transport is safer and less harmful to the passengers than road transport, which is particularly important in the delivery of patient of neurosurgical, politravmatological, cardiologycal and critical care profile at critical condition in intensive care units and operating hospitals and medical centers.

  19. Pitch angle scattering and particle precipitation in a pulsating aurora - an experimental study

    International Nuclear Information System (INIS)

    Sandahl, I.

    1984-10-01

    A pulsating aurora occurring during the recovery phase of a substorm on January 27, 1979 was monitored by a large set of instruments. The Swedish sounding rocket S23-L2 was launched at magnetic midnight over pulsating patches, some of which exhibited 3+-1 Hz modulation. The ground based instrumentation included auroral TV cameras, all sky cameras, photometers and magnetometers. The geostationary satellite GEOS-2 was located in the equatorial plane, approximately conjugate to the rocket. The central experiment of this study is the particle experiment on the rocket. Several aspects of pulsating auroras have been investigated. The auroral luminosity variations were very well correlated to variations in the flux of precipitating hot electrons. The 1-20 second pulsations were caused by increased fluxes of 4-40 keV electrons. The 3+-1 Hz modulation was detected in 7-200 keV electrons, but the biggest energy flux modulation occurred for electrons of about 60 keV. Model calculations involving the electron distributions measured by the sounding rocket and GEOS-2, consistently show that the electrons may have been scattered into the loss cone through the Doppler shifted gyroresonance with whistler mode waves. The scattering was not a pure pitch angle scattering as in the classical Coroniti and Kennel theory, but involved also a systematic energy loss from the particles. The waves were probably hiss with some chorus elements. The equatorial plane plasma density was estimated in two independent ways to be about 2x10 6 m- 3 . The 3+-1 Hz modulation was measured both by the particle experiment on the rocket and by the wave experiment on GEOS-2. Properties of the modulated fluxes are described and a qualitative model for the cause of the modulation is proposed. (author)

  20. Electrodynamics and energy characteristics of aurora at high resolution by optical methods

    Science.gov (United States)

    Dahlgren, H.; Lanchester, B. S.; Ivchenko, N.; Whiter, D. K.

    2016-06-01

    Technological advances leading to improved sensitivity of optical detectors have revealed that aurora contains a richness of dynamic and thin filamentary structures, but the source of the structured emissions is not fully understood. In addition, high-resolution radar data have indicated that thin auroral arcs can be correlated with highly varying and large electric fields, but the detailed picture of the electrodynamics of auroral filaments is yet incomplete. The Auroral Structure and Kinetics (ASK) instrument is a state-of-the-art ground-based instrument designed to investigate these smallest auroral features at very high spatial and temporal resolution, by using three electron multiplying CCDs in parallel for three different narrow spectral regions. ASK is specifically designed to utilize a new optical technique to determine the ionospheric electric fields. By imaging the long-lived O+ line at 732 nm, the plasma flow in the region can be traced, and since the plasma motion is controlled by the electric field, the field strength and direction can be estimated at unprecedented resolution. The method is a powerful tool to investigate the detailed electrodynamics and current systems around the thin auroral filaments. The two other ASK cameras provide information on the precipitation by imaging prompt emissions, and the emission brightness ratio of the two emissions, together with ion chemistry modeling, is used to give information on the energy and energy flux of the precipitating electrons. In this paper, we discuss these measuring techniques and give a few examples of how they are used to reveal the nature and source of fine-scale structuring in the aurora.

  1. Mesospheric ozone destruction by high-energy electron precipitation associated with pulsating aurora

    Science.gov (United States)

    Turunen, Esa; Kero, Antti; Verronen, Pekka T.; Miyoshi, Yoshizumi; Oyama, Shin-Ichiro; Saito, Shinji

    2016-10-01

    Energetic particle precipitation into the upper atmosphere creates excess amounts of odd nitrogen and odd hydrogen. These destroy mesospheric and upper stratospheric ozone in catalytic reaction chains, either in situ at the altitude of the energy deposition or indirectly due to transport to other altitudes and latitudes. Recent statistical analysis of satellite data on mesospheric ozone reveals that the variations during energetic electron precipitation from Earth's radiation belts can be tens of percent. Here we report model calculations of ozone destruction due to a single event of pulsating aurora early in the morning on 17 November 2012. The presence of high-energy component in the precipitating electron flux (>200 keV) was detected as ionization down to 68 km altitude, by the VHF incoherent scatter radar of European Incoherent Scatter (EISCAT) Scientific Association (EISCAT VHF) in Tromsø, Norway. Observations by the Van Allen Probes satellite B showed the occurrence of rising tone lower band chorus waves, which cause the precipitation. We model the effect of high-energy electron precipitation on ozone concentration using a detailed coupled ion and neutral chemistry model. Due to a 30 min, recorded electron precipitation event we find 14% odd oxygen depletion at 75 km altitude. The uncertainty of the higher-energy electron fluxes leads to different possible energy deposition estimates during the pulsating aurora event. We find depletion of odd oxygen by several tens of percent, depending on the precipitation characteristics used in modeling. The effect is notably maximized at the sunset time following the occurrence of the precipitation.

  2. Polarized Light Corridor Demonstrations.

    Science.gov (United States)

    Davies, G. R.

    1990-01-01

    Eleven demonstrations of light polarization are presented. Each includes a brief description of the apparatus and the effect demonstrated. Illustrated are strain patterns, reflection, scattering, the Faraday Effect, interference, double refraction, the polarizing microscope, and optical activity. (CW)

  3. Aurora B is regulated by the mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling pathway and is a valuable potential target in melanoma cells.

    Science.gov (United States)

    Bonet, Caroline; Giuliano, Sandy; Ohanna, Mickaël; Bille, Karine; Allegra, Maryline; Lacour, Jean-Philippe; Bahadoran, Philippe; Rocchi, Stéphane; Ballotti, Robert; Bertolotto, Corine

    2012-08-24

    Metastatic melanoma is a deadly skin cancer and is resistant to almost all existing treatment. Vemurafenib, which targets the BRAFV600E mutation, is one of the drugs that improves patient outcome, but the patients next develop secondary resistance and a return to cancer. Thus, new therapeutic strategies are needed to treat melanomas and to increase the duration of v-Raf murine sarcoma viral oncogene homolog B1 (BRAF) inhibitor response. The ERK pathway controls cell proliferation, and Aurora B plays a pivotal role in cell division. Here, we confirm that Aurora B is highly expressed in metastatic melanoma cells and that Aurora B inhibition triggers both senescence-like phenotypes and cell death in melanoma cells. Furthermore, we show that the BRAF/ERK axis controls Aurora B expression at the transcriptional level, likely through the transcription factor FOXM1. Our results provide insight into the mechanism of Aurora B regulation and the first molecular basis of Aurora B regulation in melanoma cells. The inhibition of Aurora B expression that we observed in vemurafenib-sensitive melanoma cells was rescued in cells resistant to this drug. Consistently, these latter cells remain sensitive to the effect of the Aurora B inhibitor. Noteworthy, wild-type BRAF melanoma cells are also sensitive to Aurora B inhibition. Collectively, our findings, showing that Aurora B is a potential target in melanoma cells, particularly in those vemurafenib-resistant, may open new avenues to improve the treatment of metastatic melanoma.

  4. Aspects of the practical application of titanium alloys after low temperature nitriding glow discharge in hydrogen- free -gas media

    Energy Technology Data Exchange (ETDEWEB)

    Mashovets, N.S., E-mail: mashovets@rambler.ru [Khmelnickiy National University (Ukraine); Pastukh, I.M., E-mail: pastim@mail.ru [Khmelnickiy National University (Ukraine); Voloshko, S.M. [Khmelnickiy National University (Ukraine); National Technical University of Ukraine “Kyiv Polytechnic Institute” (Ukraine)

    2017-01-15

    Highlights: • Surface modification of titanium alloys were carried out by low-temperature nitriding in a glow discharge in hydrogen-free environment. • Research into the phase composition was performed by X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). • The above material shows the promise of the technology of low-temperature hydrogen-nitriding by glow discharge. This greatly expands the range of practical applications of titanium alloys. - Abstract: X-ray diffraction analysis, X-ray photoelectron spectroscopy, and Electron Auger-spectroscopy investigation of phase transformation on the surface of the VT8 titanium alloy after a low temperature hydrogen-free nitriding in a glow discharge. Operational characteristics of titanium alloys defined physical-mechanical characteristics of the surface and their phase composition, which depend on the process parameters of nitriding. Surface modification of titanium alloys were carried out by low-temperature nitriding in a glow discharge in hydrogen-free environment. The main advantage of this method lies in the absence of hydrogen embrittlement and complete environmental safety process. Application of the glow discharge can not only speed up the process by the order of the diffusion surface saturation with nitrogen, but also significantly alters the kinetics of the process and quality of the nitrided layer, in particular its physio-mechanical properties and phase composition. For research purposes, the standards from an α + β alloy Ti-Al6-Cr2-Mo2,5 (VT8) were used. Research into the phase composition was performed by X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). Stratified analysis by AES was conducted by etching the surface of the samples’ argon ion beam with diameters of 1.5 mm with an energy of 3000 eV and a current density of 400 mA/cm{sup 2}. The above material shows the promise of the technology of low

  5. Aspects of the practical application of titanium alloys after low temperature nitriding glow discharge in hydrogen- free -gas media

    International Nuclear Information System (INIS)

    Mashovets, N.S.; Pastukh, I.M.; Voloshko, S.M.

    2017-01-01

    Highlights: • Surface modification of titanium alloys were carried out by low-temperature nitriding in a glow discharge in hydrogen-free environment. • Research into the phase composition was performed by X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). • The above material shows the promise of the technology of low-temperature hydrogen-nitriding by glow discharge. This greatly expands the range of practical applications of titanium alloys. - Abstract: X-ray diffraction analysis, X-ray photoelectron spectroscopy, and Electron Auger-spectroscopy investigation of phase transformation on the surface of the VT8 titanium alloy after a low temperature hydrogen-free nitriding in a glow discharge. Operational characteristics of titanium alloys defined physical-mechanical characteristics of the surface and their phase composition, which depend on the process parameters of nitriding. Surface modification of titanium alloys were carried out by low-temperature nitriding in a glow discharge in hydrogen-free environment. The main advantage of this method lies in the absence of hydrogen embrittlement and complete environmental safety process. Application of the glow discharge can not only speed up the process by the order of the diffusion surface saturation with nitrogen, but also significantly alters the kinetics of the process and quality of the nitrided layer, in particular its physio-mechanical properties and phase composition. For research purposes, the standards from an α + β alloy Ti-Al6-Cr2-Mo2,5 (VT8) were used. Research into the phase composition was performed by X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). Stratified analysis by AES was conducted by etching the surface of the samples’ argon ion beam with diameters of 1.5 mm with an energy of 3000 eV and a current density of 400 mA/cm 2 . The above material shows the promise of the technology of low

  6. Polarized Moessbauer transitions

    International Nuclear Information System (INIS)

    Barb, D.

    1975-01-01

    Theoretical aspects of the emission, absorption and scattering of polarized gamma rays are reviewed for a general case of combined magnetic and electric hyperfine interactions; various possibilities of obtaining polarized gamma sources are described and examples are given of the applications of Moessbauer spectroscopy with polarized gamma rays in solving problems of solid state physics. (A.K.)

  7. Performance and Economics of Catalytic Glow Plugs and Shields in Direct Injection Natural Gas Engines for the Next Generation Natural Gas Vehicle Program: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Mello, J. P.; Bezaire, D.; Sriramulu, S.; Weber, R.

    2003-08-01

    Subcontractor report details work done by TIAX and Westport to test and perform cost analysis for catalytic glow plugs and shields for direct-injection natural gas engines for the Next Generation Natural Gas Vehicle Program.

  8. Transient brightening of Jupiter's aurora observed by the Hisaki satellite and Hubble Space Telescope during approach phase of the Juno spacecraft

    Science.gov (United States)

    Kimura, T.; Nichols, J. D.; Gray, R.; Tao, C.; Murakami, G.; Yamazaki, A.; Badman, S. V.; Tsuchiya, F.; Yoshioka, K.; Kita, H.; Grodent, D. C.; Clark, G. B.; Yoshikawa, I.; Fujimoto, M.

    2017-12-01

    In early 2014, continuous monitoring with the Hisaki satellite discovered transient auroral emission at Jupiter during a period when the solar wind was relatively quiet for a few days. Simultaneous imaging made by the Hubble Space Telescope (HST) suggested that the transient aurora is associated with a global magnetospheric disturbance that spans from the inner to outer magnetosphere. However, the temporal and spatial evolutions of the magnetospheric disturbance were not resolved because of the lack of continuous monitoring of the transient aurora simultaneously with the imaging. Here we report the coordinated observation of the aurora and plasma torus made by Hisaki and HST during the approach phase of the Juno spacecraft in mid-2016. On day 142, Hisaki detected a transient aurora with a maximum total H2 emission power of 8.5 TW. The simultaneous HST imaging was indicative of a large `dawn storm', which is associated with tail reconnection, at the onset of the transient aurora. The outer emission, which is associated with hot plasma injection in the inner magnetosphere, followed the dawn storm within less than two Jupiter rotations. The monitoring of the torus with Hisaki indicated that the hot plasma population increased in the torus during the transient aurora. These results imply that the magnetospheric disturbance is initiated via the tail reconnection and rapidly expands toward the inner magnetosphere, followed by the hot plasma injection reaching the plasma torus. This corresponds to the radially inward transport of the plasma and/or energy from the outer to the inner magnetosphere.

  9. Rosmarinic acid plays a protective role in the embryogenesis of zebrafish exposed to food colours through its influence on aurora kinase A level.

    Science.gov (United States)

    Swarnalatha, Y; Jerrine Joseph, I S; Jayakrishna, Tippabathani

    2017-05-01

    To evaluate the protective nature of the rosmarinic acid from Sphaeranthus amaranthoides during zebra fish embryogenesis. Rosmarinic acid was isolated from the S. amaranthoides. An accurate, sensitive and simple LC-MS analysis was performed to determine the rosmarinic acid from S. amaranthoides. In the present study, zebrafish embryos were exposed to crimson red and sunset yellow at a concentration of 0.1 and 0.5mg/l and the effect of these food colours on the levels of aurora kinase A was studied individually. Aurora kinase A levels are crucial for embryogenesis in zebrafish which is used as model in this study. The decrease of aurora kinase A levels in food colour treated embryos influences the embryogenesis, resulting in short and bent trunk leading to cell death and growth retardation. Elevated levels of aurora kinase A in rosmarinic acid treated groups can be attributed to the restoration of normal growth in zebra fish embryos with well developed brain and eyes. Further insilico docking studies were carried out and target was identified as rosmarinic acid. From the docking studies the docking poses and binding energy confirms that aurora kinase A is the target for rosmarinic acid. Rosmarinic acid was found to play a protective role in the embryogenesis of zebra fish exposed to food colours (crimson red and sunset yellow) through its influence on aurora kinase A levels. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  10. Enhancing DC Glow Discharge Tube Museuum Displays using a Theremin Controlled Helmholtz Coil to Demonstrate Magnetic Confinement

    Science.gov (United States)

    Siu, Theodore; Wissel, Stephanie; Guttadora, Larry; Liao, Susan; Zwicker, Andrew

    2010-11-01

    Since their discovery in the mid 1800's, DC glow discharge apparatuses have commonly been used for spectral analysis, the demonstration of the Frank-Hertz experiment, and to study plasma breakdown voltages following from the Paschen Curve. A DC glow discharge tube museum display was outfitted with a Helmholtz Coil electromagnet in order to demonstrate magnetic confinement for a science museum display. A device commonly known as a ``theremin'' was designed and built in order to externally control the Helmholtz Coil current and the plasma current. Originally a musical instrument, a theremin has two variable capacitors connected to two radio frequency oscillators which determine pitch and volume. Using a theremin to control current and ``play'' the plasma adds appeal and durability by providing a new innovative means of interacting with a museum exhibit. Educationally, students can use the display to not only learn about plasma properties but also electronic properties of the human body.

  11. Universal sensor based on the spectroscopy of glow discharge for the detection of traces of atoms or molecules in air

    Science.gov (United States)

    Atutov, S. N.; Galeyev, A. E.; Plekhanov, A. I.; Yakovlev, A. V.

    2018-03-01

    A sensitive and versatile sensor for the detection of traces of atoms or molecules in air based on the emission spectroscopy of glow discharge in air has been developed and studied. The advantages of this sensor compared to other well-known methods are that it renders the use of ultrahigh vacuum or cryogenic temperatures superfluous. The sensor is insensitive to the presence of water vapor (for example, in exhaled air) because of the absence of strong water lines in the visible spectral range. It has a high spectral selectivity limited only by Doppler broadening of the emission lines. The high selectivity of the sensor combined with a wide spectral range allows the detection of many toxic impurities, which can be present in air. Moreover, the spectral range used covers almost all biomarkers in exhaled air, making the proposed sensor extremely interesting for medical applications. To our knowledge, the proposed method is the first based on a glow discharge in air.

  12. Analysis of read-out heating rate effects on the glow peaks of TLD-100 using WinGCF software

    Energy Technology Data Exchange (ETDEWEB)

    Bauk, Sabar, E-mail: sabar@usm.my [Physics Section, School of Distance Education, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Hussin, Siti Fatimah [School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Alam, Md. Shah [Physics Section, School of Distance Education, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Physics Department, Shahjalal University of Science and Technology, Sylhet (Bangladesh)

    2016-01-22

    This study was done to analyze the effects of the read-out heating rate on the LiF:Mg,Ti (TLD-100) thermoluminescent dosimeters (TLD) glow peaks using WinGCF computer software. The TLDs were exposed to X-ray photons with a potential difference of 72 kVp and 200 mAs in air and were read-out using a Harshaw 3500 TLD reader. The TLDs were read-out using four read-out heating rates at 10, 7, 4 and 1 °C s{sup −1}. It was observed that lowering the heating rate could separate more glow peaks. The activation energy for peak 5 was found to be lower than that for peak 4. The peak maximum temperature and the integral value of the main peak decreased as the heating rate decreases.

  13. Ipl1/Aurora kinase suppresses S-CDK-driven spindle formation during prophase I to ensure chromosome integrity during meiosis.

    Directory of Open Access Journals (Sweden)

    Louise Newnham

    Full Text Available Cells coordinate spindle formation with DNA repair and morphological modifications to chromosomes prior to their segregation to prevent cell division with damaged chromosomes. Here we uncover a novel and unexpected role for Aurora kinase in preventing the formation of spindles by Clb5-CDK (S-CDK during meiotic prophase I and when the DDR is active in budding yeast. This is critical since S-CDK is essential for replication during premeiotic S-phase as well as double-strand break induction that facilitates meiotic recombination and, ultimately, chromosome segregation. Furthermore, we find that depletion of Cdc5 polo kinase activity delays spindle formation in DDR-arrested cells and that ectopic expression of Cdc5 in prophase I enhances spindle formation, when Ipl1 is depleted. Our findings establish a new paradigm for Aurora kinase function in both negative and positive regulation of spindle dynamics.

  14. Empiric mathematical model for predicting the content of alpha-acids in hop (Humulus lupulus L.) cv. Aurora.

    Science.gov (United States)

    Srečec, Siniša; Ceh, Barbara; Ciler, Tanja Savić; Rus, Alenka Ferlež

    2013-12-01

    The aim of this research is to find a simple mathematical model due to sum of effective temperatures and rainfalls from second germination after spring pruning till the technological maturity of hop cones, in order to achieve reliable prognosis of alpha-acids content in hop cv. Aurora. After mathematical analyses of experimental data by Eurequa Formulize 0.96 Beta software 17 equations were offered, and after substituting the values of dependent and independent variables in all equations only one equation was chosen with p = 0.034 (pmaturity of hop cones. Coefficients k 1 , k 2 and k 3 are determined for cultivar Aurora (53.8, 453 and 1.33, respectively).

  15. The Physics of Polarization

    Science.gov (United States)

    Landi Degl'Innocenti, Egidio

    2015-10-01

    The introductory lecture that has been delivered at this Symposium is a condensed version of an extended course held by the author at the XII Canary Island Winter School from November 13 to November 21, 2000. The full series of lectures can be found in Landi Degl'Innocenti (2002). The original reference is organized in 20 Sections that are here itemized: 1. Introduction, 2. Description of polarized radiation, 3. Polarization and optical devices: Jones calculus and Muller matrices, 4. The Fresnel equations, 5. Dichroism and anomalous dispersion, 6. Polarization in everyday life, 7. Polarization due to radiating charges, 8. The linear antenna, 9. Thomson scattering, 10. Rayleigh scattering, 11. A digression on Mie scattering, 12. Bremsstrahlung radiation, 13. Cyclotron radiation, 14. Synchrotron radiation, 15. Polarization in spectral lines, 16. Density matrix and atomic polarization, 17. Radiative transfer and statistical equilibrium equations, 18. The amplification condition in polarized radiative transfer, and 19. Coupling radiative transfer and statistical equilibrium equations.

  16. Liquid sampling-atmospheric pressure glow discharge as a secondary excitation source: Assessment of plasma characteristics

    International Nuclear Information System (INIS)

    Manard, Benjamin T.; Gonzalez, Jhanis J.; Sarkar, Arnab; Dong, Meirong; Chirinos, Jose; Mao, Xianglei; Russo, Richard E.; Marcus, R. Kenneth

    2014-01-01

    The liquid sampling-atmospheric pressure glow discharge (LS-APGD) has been assessed as a secondary excitation source with a parametric evaluation regarding carrier gas flow rate, applied current, and electrode distance. With this parametric evaluation, plasma optical emission was monitored in order to obtain a fundamental understanding with regards to rotational temperature (T rot ), excitation temperature (T exc ), electron number density (n e ), and plasma robustness. Incentive for these studies is not only for a greater overall fundamental knowledge of the APGD, but also in instrumenting a secondary excitation/ionization source following laser ablation (LA). Rotational temperatures were determined through experimentally fitting of the N 2 and OH molecular emission bands while atomic excitation temperatures were calculated using a Boltzmann distribution of He and Mg atomic lines. The rotational and excitation temperatures were determined to be ∼ 1000 K and ∼ 2700 K respectively. Electron number density was calculated to be on the order of ∼ 3 × 10 15 cm −3 utilizing Stark broadening effects of the Hα line of the Balmer series and a He I transition. In addition, those diagnostics were performed introducing magnesium (by solution feed and laser ablation) into the plasma in order to determine any perturbation under heavy matrix sampling. The so-called plasma robustness factor, derived by monitoring Mg II/Mg I emission ratios, is also employed as a reflection of potential perturbations in microplasma energetics across the various operation conditions and sample loadings. While truly a miniaturized source ( 3 volume), the LS-APGD is shown to be quite robust with plasma characteristics and temperatures being unaffected upon introduction of metal species, whether by liquid or laser ablation sample introduction. - Highlights: • Liquid sampling-atmospheric pressure glow discharge (LS-APGD) • LS-APGD as a secondary excitation source for laser-ablated (LA

  17. v-Src causes delocalization of Mklp1, Aurora B, and INCENP from the spindle midzone during cytokinesis failure

    Energy Technology Data Exchange (ETDEWEB)

    Soeda, Shuhei [Department of Molecular Cell Biology, Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba 260-8675 (Japan); Nakayama, Yuji, E-mail: nakayama@mb.kyoto-phu.ac.jp [Department of Molecular Cell Biology, Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba 260-8675 (Japan); Department of Biochemistry and Molecular Biology, Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku, Kyoto 607-8414 (Japan); Honda, Takuya; Aoki, Azumi; Tamura, Naoki; Abe, Kohei; Fukumoto, Yasunori [Department of Molecular Cell Biology, Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba 260-8675 (Japan); Yamaguchi, Naoto, E-mail: nyama@faculty.chiba-u.jp [Department of Molecular Cell Biology, Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba 260-8675 (Japan)

    2013-06-10

    Src-family tyrosine kinases are aberrantly activated in cancers, and this activation is associated with malignant tumor progression. v-Src, encoded by the v-src transforming gene of the Rous sarcoma virus, is a mutant variant of the cellular proto-oncogene c-Src. Although investigations with temperature sensitive mutants of v-Src have shown that v-Src induces many oncogenic processes, the effects on cell division are unknown. Here, we show that v-Src inhibits cellular proliferation of HCT116, HeLa S3 and NIH3T3 cells. Flow cytometry analysis indicated that inducible expression of v-Src results in an accumulation of 4N cells. Time-lapse analysis revealed that binucleation is induced through the inhibition of cytokinesis, a final step of cell division. The localization of Mklp1, which is essential for cytokinesis, to the spindle midzone is inhibited in v-Src-expressing cells. Intriguingly, Aurora B, which regulates Mklp1 localization at the midzone, is delocalized from the spindle midzone and the midbody but not from the metaphase chromosomes upon v-Src expression. Mklp2, which is responsible for the relocation of Aurora B from the metaphase chromosomes to the spindle midzone, is also lost from the spindle midzone. These results suggest that v-Src inhibits cytokinesis through the delocalization of Mklp1 and Aurora B from the spindle midzone, resulting in binucleation. -- Highlights: • v-Src inhibits cell proliferation of HCT116, HeLa S3 and NIH3T3 cells. • v-Src induces binucleation together with cytokinesis failure. • v-Src causes delocalization of Mklp1, Aurora B and INCENP from the spindle midzone.

  18. Relation between fine structure of energy spectra for pulsating aurora electrons and frequency spectra of whistler mode chorus waves

    Czech Academy of Sciences Publication Activity Database

    Miyoshi, Y.; Saito, S.; Seki, K.; Nishiyama, T.; Kataoka, R.; Asamura, K.; Katoh, Y.; Ebihara, Y.; Sakanoi, T.; Hirahara, M.; Oyama, S.; Kurita, S.; Santolík, Ondřej

    2015-01-01

    Roč. 120, č. 9 (2015), s. 7728-7736 ISSN 2169-9380 R&D Projects: GA MŠk LH12231 Institutional support: RVO:68378289 Keywords : pulsating aurora * chorus waves * wave-particle interactions * computer simulation * Reimei satellite Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.318, year: 2015 http://onlinelibrary.wiley.com/doi/10.1002/2015JA021562/full

  19. Saturn's dayside ultraviolet auroras: Evidence for morphological dependence on the direction of the upstream interplanetary magnetic field

    Science.gov (United States)

    Meredith, C J; Alexeev, I I; Badman, S V; Belenkaya, E S; Cowley, S W H; Dougherty, M K; Kalegaev, V V; Lewis, G R; Nichols, J D

    2014-01-01

    We examine a unique data set from seven Hubble Space Telescope (HST) “visits” that imaged Saturn's northern dayside ultraviolet emissions exhibiting usual circumpolar “auroral oval” morphologies, during which Cassini measured the interplanetary magnetic field (IMF) upstream of Saturn's bow shock over intervals of several hours. The auroras generally consist of a dawn arc extending toward noon centered near ∼15° colatitude, together with intermittent patchy forms at ∼10° colatitude and poleward thereof, located between noon and dusk. The dawn arc is a persistent feature, but exhibits variations in position, width, and intensity, which have no clear relationship with the concurrent IMF. However, the patchy postnoon auroras are found to relate to the (suitably lagged and averaged) IMF Bz, being present during all four visits with positive Bz and absent during all three visits with negative Bz. The most continuous such forms occur in the case of strongest positive Bz. These results suggest that the postnoon forms are associated with reconnection and open flux production at Saturn's magnetopause, related to the similarly interpreted bifurcated auroral arc structures previously observed in this local time sector in Cassini Ultraviolet Imaging Spectrograph data, whose details remain unresolved in these HST images. One of the intervals with negative IMF Bz however exhibits a prenoon patch of very high latitude emission extending poleward of the dawn arc to the magnetic/spin pole, suggestive of the occurrence of lobe reconnection. Overall, these data provide evidence of significant IMF dependence in the morphology of Saturn's dayside auroras. Key Points We examine seven cases of joint HST Saturn auroral images and Cassini IMF data The persistent but variable dawn arc shows no obvious IMF dependence Patchy postnoon auroras are present for northward IMF but not for southward IMF PMID:26167441

  20. Retratos de Aurora: Deconstrucción de una memoria derrumbada

    Directory of Open Access Journals (Sweden)

    Nicolás Sáez Gutiérrez

    2017-12-01

    Full Text Available Hemos decido publicar en este número el proyecto Retratos de Aurora coordinado por Walter Blas1 , como una manera de visibilizar acciones que desde el arte y su enseñanza logran transcender al entorno donde se ha efectuado dicha acción. Aquí la fotografía y el propio aparato fotográfico son el medio instrumental propuesto para construir la historia viva de la emblemática población “Aurora de Chile”.2 Las vecinas y vecinos fueron invitados por Walter a construir artesanalmente cámaras estenopeicas (sin lente adaptando objetos de su cotidiano y su memoria. Una antigua caja de madera, un lechero de aluminio, un madero de la antigua fábrica, un motor de arranque y hasta el estuche de un acordeón reliquia familiar son las formas cotidianas que se transformaron en mecanismos de captura fotográfica del propio territorio. Estos inventos caseros permitieron no solo comprender didácticamente el procedimiento técnico de la fijación química de la imagen producida por el fenómeno físico lumínico conocido como “cámara obscura”, si no que a dar un nuevo y mágico destino a estas “cámaras latentes”. Objetos que cargan con sus respectivos "relatos de existencia”, se transforman y vuelven a tener una utilidad impensada que las conecta con la intimidad familiar y la memoria colectiva. Desde ahí son operadas para construir un imaginario actualizado de lo que ha sido la población hasta hoy y para ser parte de una especie de inventario visual que prevalezca en el tiempo, como bien lo dijo Sontag “la fotografía es un inventario de la inmortalidad”.3 Las fotografías estenopeicas resultantes construyen un nuevo paisaje de la población “Aurora de Chile”. Un paisaje de resistencia, que enaltece su patrimonio humano y cultural, que activa a la memoria pasada pero que sabe construirá la futura... que desea ser un paisaje discursivo que denuncia su empoderada existencia. En nuestra actual era de la

  1. Size-Controlled Synthesis of Colloidal Gold Nanoparticles at Room Temperature Under the Influence of Glow Discharge

    Directory of Open Access Journals (Sweden)

    Liang Xi

    2009-01-01

    Full Text Available Abstract Highly dispersed colloidal gold (Au nanoparticles were synthesized at room temperature using glow discharge plasma within only 5 min. The prepared Au colloids were characterized with UV–visible absorption spectra (UV–vis, X-ray photoelectron spectroscopy (XPS, and transmission electron microscopy (TEM equipped with an energy dispersion X-ray spectrometer (EDX. UV–vis, XPS and EDX results confirmed that Au3+ ions in HAuCl4 solution could be effectively reduced into the metallic state at room temperature with the glow discharge plasma. TEM images showed that Au nanoparticles were highly dispersed. The size of colloidal Au nanoparticles could be easily tuned in the nanometer range by adjusting the initial concentration of HAuCl4 solution. Moreover, the as-synthesized Au colloids (d av = 3.64 nm exhibited good catalytic activity for glucose oxidation. The nucleation and growth of colloidal Au particles under the influence of the plasma was closely related with the high-energy electrons generated by glow discharge plasma.

  2. DC negative corona discharge in atmospheric pressure helium: transition from the corona to the ‘normal’ glow regime

    International Nuclear Information System (INIS)

    Hasan, Nusair; Farouk, Bakhtier; Antao, Dion S

    2014-01-01

    Direct current (dc) negative corona discharges in atmospheric pressure helium are simulated via detailed numerical modeling. Simulations are conducted to characterize the discharges in atmospheric helium for a pin plate electrode configuration. A self-consistent two-dimensional hybrid model is developed to simulate the discharges and the model predictions are validated with experimental measurements. The discharge model considered consists of momentum and energy conservation equations for a multi-component (electrons, ions, excited species and neutrals) gas mixture, conservation equations for each component of the mixture and state relations. A drift–diffusion approximation for the electron and the ion fluxes is used. A model for the external circuit driving the discharge is also considered and solved along with the discharge model. Many of the key features of a negative corona discharge, namely non-linear current–voltage characteristics, spatially flat cathode current density and glow-like discharge in the high current regime are displayed in the predictions. A transition to the ‘normal’ glow discharge from the corona discharge regime is also observed. The transition is identified from the calculated current–voltage characteristic curve and is characterized by the radial growth of the negative glow and the engulfment of the cathode wire. (paper)

  3. Model Insensitive and Calibration Independent Method for Determination of the Downstream Neutral Hydrogen Density Through Ly-alpha Glow Observations

    Science.gov (United States)

    Gangopadhyay, P.; Judge, D. L.

    1996-01-01

    Our knowledge of the various heliospheric phenomena (location of the solar wind termination shock, heliopause configuration and very local interstellar medium parameters) is limited by uncertainties in the available heliospheric plasma models and by calibration uncertainties in the observing instruments. There is, thus, a strong motivation to develop model insensitive and calibration independent methods to reduce the uncertainties in the relevant heliospheric parameters. We have developed such a method to constrain the downstream neutral hydrogen density inside the heliospheric tail. In our approach we have taken advantage of the relative insensitivity of the downstream neutral hydrogen density profile to the specific plasma model adopted. We have also used the fact that the presence of an asymmetric neutral hydrogen cavity surrounding the sun, characteristic of all neutral densities models, results in a higher multiple scattering contribution to the observed glow in the downstream region than in the upstream region. This allows us to approximate the actual density profile with one which is spatially uniform for the purpose of calculating the downstream backscattered glow. Using different spatially constant density profiles, radiative transfer calculations are performed, and the radial dependence of the predicted glow is compared with the observed I/R dependence of Pioneer 10 UV data. Such a comparison bounds the large distance heliospheric neutral hydrogen density in the downstream direction to a value between 0.05 and 0.1/cc.

  4. Investigation of Gas Heating by Nanosecond Repetitively Pulsed Glow Discharges Used for Actuation of a Laminar Methane-Air Flame

    KAUST Repository

    Lacoste, Deanna

    2017-05-24

    This paper reports on the quantification of the heating induced by nanosecond repetitively pulsed (NRP) glow discharges on a lean premixed methane-air flame. The flame, obtained at room temperature and atmospheric pressure, has an M-shape morphology. The equivalence ratio is 0.95 and the thermal power released by the flame is 113 W. The NRP glow discharges are produced by high voltage pulses of 10 ns duration, 7 kV amplitude, applied at a repetition frequency of 10 kHz. The average power of the plasma, determined from current and voltage measurements, is 1 W, i.e. about 0.9 % of the thermal power of the flame. Broadband vibrational coherent anti-Stokes Raman spectroscopy of nitrogen is used to determine the temperature of the flame with and without plasma enhancement. The temperature evolution in the flame area shows that the thermal impact of NRP glow discharges is in the uncertainty range of the technique, i.e., +/- 40 K.

  5. Aurora kinases as druggable targets in pediatric leukemia: heterogeneity in target modulation activities and cytotoxicity by diverse novel therapeutic agents.

    Directory of Open Access Journals (Sweden)

    Aarthi Jayanthan

    Full Text Available Leukemia is the most common pediatric malignancy, constituting more than 30% of all childhood cancers. Although cure rates have improved greatly, approximately one in five children relapse and poor survival rates post relapse remain a challenge. Given this, more effective and innovative therapeutic strategies are needed in order to improve prognosis. Aurora kinases, a family of serine/threonine kinases essential for the regulation of several mitotic processes, have been identified as potential targets for cancer therapeutics. Elevated expression of Aurora kinases has been demonstrated in several malignancies and is associated with aberrant mitotic activity, aneuploidy and alterations in chromosomal structure and genome instability. Based on this rationale, a number of small molecule inhibitors have been formulated and advanced to human studies in the recent past. A comparative analysis of these agents in cytotoxicity and target modulation analyses against a panel of leukemia cells provides novel insights into the unique mechanisms and codependent activity pathways involved in targeting Aurora kinases, constituting a distinctive preclinical experimental framework to identify appropriate agents and combinations in future clinical studies.

  6. Combining the pan-aurora kinase inhibitor AMG 900 with histone deacetylase inhibitors enhances antitumor activity in prostate cancer

    International Nuclear Information System (INIS)

    Paller, Channing J; Wissing, Michel D; Mendonca, Janet; Sharma, Anup; Kim, Eugene; Kim, Hea-Soo; Kortenhorst, Madeleine S Q; Gerber, Stephanie; Rosen, Marc; Shaikh, Faraz; Zahurak, Marianna L; Rudek, Michelle A; Hammers, Hans; Rudin, Charles M; Carducci, Michael A; Kachhap, Sushant K

    2014-01-01

    Histone deacetylase inhibitors (HDACIs) are being tested in clinical trials for the treatment of solid tumors. While most studies have focused on the reexpression of silenced tumor suppressor genes, a number of genes/pathways are downregulated by HDACIs. This provides opportunities for combination therapy: agents that further disable these pathways through inhibition of residual gene function are speculated to enhance cell death in combination with HDACIs. A previous study from our group indicated that mitotic checkpoint kinases such as PLK1 and Aurora A are downregulated by HDACIs. We used in vitro and in vivo xenograft models of prostate cancer (PCA) to test whether combination of HDACIs with the pan-aurora kinase inhibitor AMG 900 can synergistically or additively kill PCA cells. AMG 900 and HDACIs synergistically decreased cell proliferation activity and clonogenic survival in DU-145, LNCaP, and PC3 PCA cell lines compared to single-agent treatment. Cellular senescence, polyploidy, and apoptosis was significantly increased in all cell lines after combination treatment. In vivo xenograft studies indicated decreased tumor growth and decreased aurora B kinase activity in mice treated with low-dose AMG 900 and vorinostat compared to either agent alone. Pharmacodynamics was assessed by scoring for phosphorylated histone H3 through immunofluorescence. Our results indicate that combination treatment with low doses of AMG 900 and HDACIs could be a promising therapy for future clinical trials against PCA

  7. Antifouling activity by sea anemone (Heteractis magnifica and H. aurora extracts against marine biofilm bacteria Actividades antiincrustantes de las extractos de las anémonas marinas Heteractis magnifica y H. aurora frente a biofilm de bacterias marinas

    Directory of Open Access Journals (Sweden)

    Subramanian Bragadeeswaran

    2011-07-01

    Full Text Available Sea anemones (Actiniaria are solitary, ocean-dwelling members of the phylum Cnidaria and the class Anthozoa. In this study, we screened antibacterial activity of two benthic sea anemones (Heteractis magnifica and H. aurora collected from the Mandapam coast of southeast India. Crude extracts of the sea anemone were assayed against seven bacterial biofilms isolated from three different test panels. The crude extract of H. magnifica showed a maximum inhibition zone of 18 mm against Pseudomonas sp. and Escherichia coli and a minimum inhibition zone of 3 mm against Pseudomonas aeruginosa, Micrococcus sp., and Bacillus cerens for methanol, acetone, and DCM extracts, respectively. The butanol extract of H. aurora showed a maximum inhibition zone of 23 mm against Vibrio parahaemolyticus, whereas the methanol extract revealed a minimum inhibition zone of 1 mm against V. parahaemolyticus. The present study revealed that the H. aurora extracts were more effective than those of H. magnifica and that the active compounds from the sea anemone can be used as antifouling compounds.Las anémonas de mar (Actiniaria son solitarias, habitantes oceánicos del phylum Cnidaria y de la clase Anthozoa. En este estudio se determina la actividad antibacteriana de dos anémonas bentónicas Heteractis magnifica y H. aurora recolectadas en la costa de Mandapam, sudeste de India. Los extractos crudos de estas anémonas fueron ensayados frente a siete biofilms bacterianos aislados de tres paneles de control distintos. El extracto crudo de la anémona H. magnifica mostró una zona inhibición máxima de 18 mm contra Psudomonas sp. y Escherichia coli y la zona de inhibición mínima de 3 mm fue encontrada frente a Pseudomonas aeruginosa, Micrococus sp. y Bacillus cerens de extractos de metanol, acetona y DCM respectivamente. El extracto de butanol de la anémona H. magnifica mostró una zona de inhibición máxima de 23 mm frente a Vibrio parahemolyticus, mientras que con el

  8. A statistical analysis of the location and width of Saturn's southern auroras

    Directory of Open Access Journals (Sweden)

    S. V. Badman

    2006-12-01

    Full Text Available A selection of twenty-two Hubble Space Telescope images of Saturn's ultraviolet auroras obtained during 1997–2004 has been analysed to determine the median location and width of the auroral oval, and their variability. Limitations of coverage restrict the analysis to the southern hemisphere, and to local times from the post-midnight sector to just past dusk, via dawn and noon. It is found that the overall median location of the poleward and equatorward boundaries of the oval with respect to the southern pole are at ~14° and ~16° co-latitude, respectively, with a median latitudinal width of ~2°. These median values vary only modestly with local time around the oval, though the poleward boundary moves closer to the pole near noon (~12.5° such that the oval is wider in that sector (median width ~3.5° than it is at both dawn and dusk (~1.5°. It is also shown that the position of the auroral boundaries at Saturn are extremely variable, the poleward boundary being located between 2° and 20° co-latitude, and the equatorward boundary between 6° and 23°, this variability contrasting sharply with the essentially fixed location of the main oval at Jupiter. Comparison with Voyager plasma angular velocity data mapped magnetically from the equatorial magnetosphere into the southern ionosphere indicates that the dayside aurora lie poleward of the main upward-directed field-aligned current region associated with corotation enforcement, which maps to ~20°–24° co-latitude, while agreeing reasonably with the position of the open-closed field line boundary based on estimates of the open flux in Saturn's tail, located between ~11° and ~15°. In this case, the variability in location can be understood in terms of changes in the open flux present in the system, the changes implied by the Saturn data then matching those observed at Earth as fractions of the total planetary flux. We infer that the broad (few degrees diffuse auroral emissions

  9. Non-local effects in a stratified glow discharge with dust particles

    Energy Technology Data Exchange (ETDEWEB)

    Sukhinin, G I; Fedoseev, A V [Institute of Thermophysics SB RAS, Lavrentyev Ave., 1, Novosibirsk, 630090 (Russian Federation); Ramazanov, T S; Amangaliyeva, R Zh; Dosbalayev, M K; Jumabekov, A N [Institute of Experimental and Theoretical Physics, Al Farabi Kazakh National University, Tole Bi, 96a, Almaty, 050012 (Kazakhstan)], E-mail: fedoseev@itp.nsc.ru

    2008-12-21

    The work is aimed at describing non-local effects in the positive column of a low-pressure stratified dc glow discharge in argon with dust particles in a vertical cylindrical discharge tube. Numerical calculations of plasma parameters in the axis of the discharge tube were performed with the help of a hybrid model based on the solution of a non-local Boltzmann equation for electron energy distribution function (EEDF). Axial distributions of optical emission from striations with dust particles were measured experimentally. Negatively charged dust particles in a low-pressure stratified gas discharge should levitate at the anode-side branch of an electric field distribution above its maximum. At the same time the experiments showed that the dust particles levitate at the cathode side of a stratum. This paradox is explained by the fact that in a low-pressure striated discharge the optical emission distribution is displaced relative to the electric field distribution that was shown both by numerical simulations and experimental measurements.

  10. Formation Of Chromium Nitride Layers Produced By MOPACVD Processes Under Glow Discharge Conditions

    Science.gov (United States)

    Sobiecki, Jerzy Robert; Wierzchoń, Tadeusz

    2011-01-01

    Because of the ecological aspect the electrochemical process of obtaining chromium coatings should be replaced by other technologies. The production of chromium coating involves as the main component of the bath chromium trioxide CrO3 which is very carcinogenic. Moreover the current efficiency of this process is very low what makes it very uneconomical in order to obtain coatings several μm thick. That is why the new method of obtaining the chromium and chromium nitride coating are searched. The new hybrid technology combining plasma nitriding and PACVD method with the use of metalorganic compounds could have the big practical aspect. This method can be applied for the details with complicated shapes. The paper presents the microstructure and useful properties like corrosion and wear resistance of chromium nitride layers produced by hybrid process which consists of first depositing of chromium coating by PAMOCVD method form liquid precursor 2-ethylheksanoate chromium (III) and then annealing so obtained coating in nitrogen and hydrogen atmosphere using the glow discharge conditions.

  11. Contact glow discharge electrolysis: its origin, plasma diagnostics and non-faradaic chemical effects

    International Nuclear Information System (INIS)

    Sen Gupta, Susanta K

    2015-01-01

    Contact glow discharge electrolysis (CGDE) also termed plasma electrolysis is a novel electrolysis where a stable sheath of light emitting plasma develops around an electrode immersed well inside a relatively high-conductivity liquid electrolyte during normal electrolysis (NE) at several hundred volts. The phenomenon may develop in dc-, pulsed dc-, ac- as well as RF-driven electrolyses. The chemical effects of CGDE are remarkably non-faradaic in respect to the nature of the products as well as their yields. The article traces comprehensively the progress made in studies of CGDE in aqueous and non-aqueous solutions since 1844 and reviews the developments in the understanding of its origin, light emission, plasma state and non-faradaic effects leading to the elucidation of detailed mechanism of the origin of CGDE on the basis of the onset of hydrodynamic instabilities in local vaporization of the solvent near the working electrode during NE, and that of highly non-faradaic effects of CGDE based on a model of two reaction zones located within the electrode plasma and at the plasma–liquid interface producing solvent derived radicals at high local concentrations. Keeping in view the recent surge of interest in varied applications of CGDE, the article is appended with highlights of these applications across synthetic chemistry, waste water treatment, electrosurgical devices, nanoparticle fabrications, surface engineering and micro-machining. (topical review)

  12. Control of plasma properties in a short direct-current glow discharge with active boundaries

    Energy Technology Data Exchange (ETDEWEB)

    Adams, S. F. [Air Force Research Laboratory, WPAFB, Ohio 45433 (United States); Demidov, V. I., E-mail: vladimir.demidov@mail.wvu.edu [Air Force Research Laboratory, WPAFB, Ohio 45433 (United States); West Virginia University, Morgantown, West Virginia 26506 (United States); Bogdanov, E. A.; Kudryavtsev, A. A. [St. Petersburg State University, St. Petersburg 199034 (Russian Federation); Koepke, M. E. [West Virginia University, Morgantown, West Virginia 26506 (United States); Kurlyandskaya, I. P. [St. Petersburg University of State Fire Service of EMERCOM RF, Murmansk Branch, Murmansk 183040 (Russian Federation)

    2016-02-15

    To demonstrate controlling electron/metastable density ratio and electron temperature by applying negative voltages to the active (conducting) discharge wall in a low-pressure plasma with nonlocal electron energy distribution function, modeling has been performed in a short (lacking the positive-column region) direct-current glow discharge with a cold cathode. The applied negative voltage can modify the trapping of the low-energy part of the energetic electrons that are emitted from the cathode sheath and that arise from the atomic and molecular processes in the plasma within the device volume. These electrons are responsible for heating the slow, thermal electrons, while production of slow electrons (ions) and metastable atoms is mostly due to the energetic electrons with higher energies. Increasing electron temperature results in increasing decay rate of slow, thermal electrons (ions), while decay rate of metastable atoms and production rates of slow electrons (ions) and metastable atoms practically are unchanged. The result is in the variation of electron/metastable density ratio and electron temperature with the variation of the wall negative voltage.

  13. Influence of dust particles on positive column of DC glow discharge

    Science.gov (United States)

    Tian, Ruihuan; Yuan, Chengxun; Li, Hui; Liang, Yonggan; Wu, Jian; Kudryavtsev, A. A.; Kirsanov, G. V.; Zhou, Zhongxiang; Jiang, Yongyuan

    2018-03-01

    A self-consistent model of a DC glow discharge with dust particles based on orbital motion limited theory, collision enhanced collection approximation, and a fluid approach extended by energy conservation equation is presented. The model indicates the influence of dust particles on radical distributions of plasma parameters in positive columns. Dust particles are embedded in the positive column with the density profile prescribed as a given step function. It is shown that with the increase in dust particle density, electron density and the radical electric field decrease in the dust region. For high dust density, especially when the loss of ions and electrons on the dust surface exceeds their production in ionization collisions in the dust region, a local minimum of electron density forms in the discharge axis and the radical electric field obtained from the Poisson equation becomes non-monotonous. The addition of dust increases the longitudinal electric field and electron temperature simultaneously to compensate the electron and ion loss on dust particles and preserve the discharge.

  14. Submerged Glow-Discharge Plasma: An Economical Approach to Convert Construction Scrap Metal into Nanomaterials

    Science.gov (United States)

    Yek, Peter Nai Yuh; Rafiq Mirza Julaihi, Muhammad; Shahril Osman, Mohammad; Tiong, Tung Chuan; Lee, Wak Ha; Leing Lee, Chern

    2018-03-01

    Submerged glow-discharge plasma (SGDP) is relatively new among the various methods available for nanomaterials synthesis (NMs) techniques. This method allows great control over the production cost of nanomaterials synthesis. A lab-scale batch type SDGP technology has been constructed to produce nanomaterials and investigate the inter-relationship between plasma excitation voltages, electrodes submerged areas and electrolyte concentration. Metal oxide nanospheres has been synthesised from different electrolyte concentrations (1M-0.001M) and characterized by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). As the major results showed that the nanospheres are uniformly spherical with diameter size distribution are between 100 nm - 2μm. EDS analysis shown the nano-Iron Oxide have been formed. Scrap metal initially showed around 6.45% and 93.55% of Carbon and Iron composition respectively. After SGDP process to the scrap metal, Carbon content has increased to 34-35% and Iron content has reduced to around 15-40%. EDS results also shown the higher percentage of Iron amount has remained with lower electrolyte concentration and Current is proportionally related to submersion area of cathode.

  15. Surface treatment of polyethylene terephthalate film using atmospheric pressure glow discharge in air

    International Nuclear Information System (INIS)

    Fang Zhi; Qiu Yuchang; Wang Hui

    2004-01-01

    Non-thermal plasmas under atmospheric pressure are of great interest in polymer surface processing because of their convenience, effectiveness and low cost. In this paper, the treatment of Polyethylene terephthalate (PET) film surface for improving hydrophilicity using the non-thermal plasma generated by atmospheric pressure glow discharge (APGD) in air is conducted. The discharge characteristics of APGD are shown by measurement of their electrical discharge parameters and observation of light-emission phenomena, and the surface properties of PET before and after the APGD treatment are studied using contact angle measurement, x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). It is found that the APGD is homogeneous and stable in the whole gas gap, which differs from the commonly filamentary dielectric barrier discharge (DBD). A short time (several seconds) APGD treatment can modify the surface characteristics of PET film markedly and uniformly. After 10 s APGD treatment, the surface oxygen content of PET surface increases to 39%, and the water contact angle decreases to 19 degree, respectively. (authors)

  16. Studies on gas breakdown in pulsed radio frequency atmospheric pressure glow discharges

    International Nuclear Information System (INIS)

    Huo, W. G.; Jian, S. J.; Yao, J.; Ding, Z. F.

    2014-01-01

    In pulsed RF atmospheric pressure glow discharges, the gas breakdown judged by the rapid drop in the amplitude of the pulsed RF voltage is no longer universally true. The steep increment of the plasma-absorbed RF power is proposed to determine the gas breakdown. The averaged plasma-absorbed RF power over a pulse period is used to evaluate effects of the preceding pulsed RF discharge on the breakdown voltage of the following one, finding that the breakdown voltage decreases with the increment in the averaged plasma-absorbed RF power under constant pulse duty ratio. Effects of the pulse off-time on the breakdown voltage and the breakdown delay time are also studied. The obtained dependence of the breakdown voltage on the pulse off-time is indicative of the transitional plasma diffusion processes in the afterglow. The breakdown voltage varies rapidly as the plasma diffuses fast in the region of moderate pulse off-time. The contribution of nitrogen atom recombination at the alumina surface is demonstrated in the prolonged memory effect on the breakdown delay time vs. the pulse off-time and experimentally validated by introducing a trace amount of nitrogen into argon at short and long pulse off-times

  17. Liquid sampling-atmospheric pressure glow discharge as a secondary excitation source: Assessment of plasma characteristics

    Science.gov (United States)

    Manard, Benjamin T.; Gonzalez, Jhanis J.; Sarkar, Arnab; Dong, Meirong; Chirinos, Jose; Mao, Xianglei; Russo, Richard E.; Marcus, R. Kenneth

    The liquid sampling-atmospheric pressure glow discharge (LS-APGD) has been assessed as a secondary excitation source with a parametric evaluation regarding carrier gas flow rate, applied current, and electrode distance. With this parametric evaluation, plasma optical emission was monitored in order to obtain a fundamental understanding with regards to rotational temperature (Trot), excitation temperature (Texc), electron number density (ne), and plasma robustness. Incentive for these studies is not only for a greater overall fundamental knowledge of the APGD, but also in instrumenting a secondary excitation/ionization source following laser ablation (LA). Rotational temperatures were determined through experimentally fitting of the N2 and OH molecular emission bands while atomic excitation temperatures were calculated using a Boltzmann distribution of He and Mg atomic lines. The rotational and excitation temperatures were determined to be ~ 1000 K and ~ 2700 K respectively. Electron number density was calculated to be on the order of ~ 3 × 1015 cm- 3 utilizing Stark broadening effects of the Hα line of the Balmer series and a He I transition. In addition, those diagnostics were performed introducing magnesium (by solution feed and laser ablation) into the plasma in order to determine any perturbation under heavy matrix sampling. The so-called plasma robustness factor, derived by monitoring Mg II/Mg I emission ratios, is also employed as a reflection of potential perturbations in microplasma energetics across the various operation conditions and sample loadings. While truly a miniaturized source (laser ablation sample introduction.

  18. Pulsed laser ablation of borax target in vacuum and hydrogen DC glow discharges

    Science.gov (United States)

    Kale, A. N.; Miotello, A.; Mosaner, P.

    2006-09-01

    The aim of our experiment was to produce a material with B sbnd H bonds for applications in hydrogen storage and generation. By using KrF excimer laser ( λ = 248 nm) ablation of borax (Na 2B 4O 7) target, thin films were deposited on KBr and silicon substrates. Ablation was performed both in vacuum and in hydrogen atmosphere. DC glow discharge technique was utilized to enhance hydrogen gas ionization. Experiments were performed using laser fluence from 5 to 20 J/cm 2. Films were deposited under gas pressure of 1 × 10 -5 to 5 × 10 -2 mbar and substrate temperatures of 130-450 °C. Scanning electron microscopy analysis of films showed presence of circular particulates. Film thickness, roughness and particulates number increased with increase in laser fluence. Energy dispersive X-ray spectroscopy analysis shows that sodium content in the particulates is higher than in the target. This effect is discussed in terms of atomic arrangements (both at surface and bulk) in systems where ionic and covalent bonds are present and by looking at the increased surface/bulk ratio of the particulates with respect to the deposited films. The Fourier transform infrared spectroscopy measurements showed presence of B sbnd O stretching and B sbnd O sbnd B bending bonds. Possible reasons for absence of B sbnd H bonds are attributed to binding enthalpy of the competing molecules.

  19. Luminescence characteristics and glow curves analysis of Cu+ doped Li3PO4 phosphor

    International Nuclear Information System (INIS)

    Aghalte, G.A.; Dhoble, S.J.; Pawar, N.R.

    2016-01-01

    Li 3 PO 4 :Cu exhibits useful TL properties in personnel dosimetry of ionizing radiations. Cu is known to be one of the most efficient activator. The PL intensity is found to increase consistently with the increasing quenching temperature. Cu + doped Li 3 PO 4 phosphor was synthesized by the wet chemical co-precipitation method. The crystal structure and particle morphology of the phosphor was investigated by using X-ray diffraction and scanning electron microscopy. Li 3 PO 4 :Cu is excellent phosphor for TL dosimetry. For the synthesis of Li 3 PO 4 :Cu phosphor the stoichiometric amounts of LiOH·H 2 O and CuSO 4 · 5 H 2 O were dissolved separately and then the solutions were mixed together. It was precipitated by using concentrated H 3 PO 4 . The precipitate was filtered out immediately and kept 12 hours below IR lamp. Prepared dry Li 3 PO 4 :Cu powder was then put on 2.5 wt% NH 4 Cl in graphite crucible in preheated furnace at 800°C and was kept for 1 hour. It was then rapidly quenched to room temperature. Thermoluminescence (TL) glow curves were recorded on Nucleonix TL Reader with a heating rate of 2°C per second in the temperature range of 50-250°C. The PMT voltage was 750 volts. Photoluminescence (PL) studies were carried out by Hitachi F-4000 spectrophotometer with a spectral slit width of 1.5 nm

  20. UN2−x layer formed on uranium metal by glow plasma nitriding

    International Nuclear Information System (INIS)

    Long, Zhong; Hu, Yin; Chen, Lin; Luo, Lizhu; Liu, Kezhao; Lai, Xinchun

    2015-01-01

    Highlights: • We used a very simple method to prepare nitride layer on uranium metal surface. • This modified layer is nitrogen-rich nitride, which should be written as UN 2−x . • TEM images show the nitride layer is composed of nano-sized grains. • XPS analysis indicates there is uranium with abnormal low valence in the nitride. - Abstract: Glow plasma nitriding is a simple and economical surface treatment method, and this technology was used to prepare nitride layer on the surface of uranium metal with thickness of several microns. The composition and structure of the nitride layer were analyzed by AES and XRD, indicating that this modified layer is nitrogen-rich uranium nitride, which should be written as UN 2−x . TEM images show the nitride layer is composed of nano-sized grains, with compact structure. And XPS analysis indicates there is uranium with abnormal low valence existing in the nitride. After the treated uranium storage in air for a long time, oxygen just entered the surface several nanometers, showing the nitride layer has excellent oxidation resistance. The mechanism of nitride layer formation and low valence uranium appearance is discussed

  1. Functionalized luminescent nanocrystals on patterned surfaces obtained by radio frequency glow discharges

    Science.gov (United States)

    Sardella, E.; Liuzzi, F.; Comparelli, R.; Depalo, N.; Striccoli, M.; Agostiano, A.; Favia, P.; Curri, M. L.

    2013-04-01

    In this work a genuine combination of a bottom-up approach, which is based on synthesis and functionalization of emitting nanocrystals (NCs), with a top-down strategy, which relies on a flexible and versatile cold plasma process, is shown. Luminescent semiconducting colloidal NCs consisting of a CdSe core coated with a ZnS shell (CdSe@ZnS) are directly assembled onto micro-patterned substrates previously functionalized by means of glow discharges performed through physical masks. The NC assembly is driven by electrostatic interactions that led to their successful organization into spatially resolved domains. Two distinct protocols are tested, the former using a plasma deposition process combined with an electrostatic layer-by-layer procedure, the latter based on a two-step plasma deposition/treatment process. The procedures are thoroughly monitored with fluorescence microscopy, atomic force microscopy, x-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy and scanning electron microscopy. The two-step plasma protocol is demonstrated to be more efficient in directing a uniform and specific assembly of luminescent NCs with respect to the hybrid procedure. The presented ‘mix and match’ approach offers great potential for integrating NCs, with their unique size-dependent properties, into microstructures, providing a universal platform for the fabrication of sensors, biochips, displays and switches.

  2. Cell treatment and surface functionalization using a miniature atmospheric pressure glow discharge plasma torch

    International Nuclear Information System (INIS)

    Yonson, S; Coulombe, S; Leveille, V; Leask, R L

    2006-01-01

    A miniature atmospheric pressure glow discharge plasma torch was used to detach cells from a polystyrene Petri dish. The detached cells were successfully transplanted to a second dish and a proliferation assay showed the transplanted cells continued to grow. Propidium iodide diffused into the cells, suggesting that the cell membrane had been permeabilized, yet the cells remained viable 24 h after treatment. In separate experiments, hydrophobic, bacteriological grade polystyrene Petri dishes were functionalized. The plasma treatment reduced the contact angle from 93 0 to 35 0 , and promoted cell adhesion. Two different torch nozzles, 500 μm and 150 μm in internal diameter, were used in the surface functionalization experiments. The width of the tracks functionalized by the torch, as visualized by cell adhesion, was approximately twice the inside diameter of the nozzle. These results indicate that the miniature plasma torch could be used in biological micropatterning, as it does not use chemicals like the present photolithographic techniques. Due to its small size and manouvrability, the torch also has the ability to pattern complex 3D surfaces

  3. On copper diffusion in silicon measured by glow discharge mass spectrometry.

    Science.gov (United States)

    Modanese, Chiara; Gaspar, Guilherme; Arnberg, Lars; Di Sabatino, Marisa

    2014-11-01

    Copper contamination occurs frequently in silicon for photovoltaic applications due to its very fast diffusion coupled with a low solid solubility, especially at room temperature. The combination of these properties exerts a challenge on the direct analysis of Cu bulk concentration in Si by sputtering techniques like glow discharge mass spectrometry (GDMS). This work aims at addressing the challenges in quantitative analysis of fast diffusing elements in Si matrix by GDMS. N-type, monocrystalline (Czochralski) silicon samples were intentionally contaminated with Cu after solidification and consequently annealed at 900 °C to ensure a homogeneous distribution of Cu in the bulk. The samples were quenched after annealing to control the extent of the diffusion to the surface prior to the GDMS analyses, which were carried out at different time intervals from within few minutes after cooling onward. The Cu profiles were measured by high-resolution GDMS operating in a continuous direct current mode, where the integration step length was set to ∼0.5 μm over a total sputtered depth of 8-30 μm. The temperature of the samples during the GDMS analyses was also measured in order to evaluate the diffusion. The Cu contamination of n-type Si samples was observed to be highly material dependent. The practical impact of Cu out-diffusion on the calculation of the relative sensitivity factor (RSF) of Cu in Si is discussed.

  4. Experimental study of the negative glow and cathode sheath of an electron beam discharge

    International Nuclear Information System (INIS)

    Zeller, Philippe

    1988-01-01

    This research thesis reports the study of a middle-pressure (0.1-5 Torr) discharge in which a negative-glow-type plasma is created by a continuous electron beam (1 to 10 keV, 1 to 30 mA/cm 2 ). Such a discharge is characterised by a highly abnormal cathodic drop with a beam generation displaying an electric efficiency close to 1. In a first part, the author presents the main operation characteristics, discharge regimes and emission spectrum, and discusses bibliographical data related to cathode emission processes and to the distribution function of plasma electron velocities. The author then describes an original method of measurement of plasma conductivity. In the next part, he reports the study of the cathode region in which the electron beam generation occurs. The electric field has been measured in this region by using spatially resolved laser opto-galvanic spectroscopy. Results highlight an essentially linear spatial decay of the field. Besides, and based on these results, the author indicates scale laws leading to simple relationships between discharge parameters [fr

  5. Surface Modification of Asymmetric Polysulfone/Polyethylene Glycol Membranes by DC Ar-Glow Discharge Plasma

    Directory of Open Access Journals (Sweden)

    Chalad Yuenyao

    2016-01-01

    Full Text Available Polysulfone/polyethylene glycol (PSF/PEG membranes were prepared by dry/wet phase inversion method. Effects of direct current glow discharge plasma using argon as working gas on morphological structures and gas separation properties of membranes were studied. Alteration of membrane characteristics were analyzed by various techniques like contact angle, scanning electron microscope, Fourier transform infrared spectroscopy, and dynamic mechanical thermal analysis. Gas separation properties were measured in terms of permeation and ideal O2/N2 selectivity. Results showed that hydrophilic and gas separation properties of PSF/PEG membranes increased by plasma surface modification. It was also shown that the dosage of PEG and plasma treatment affected the morphological structures and mechanical and gas separation properties. The macro voids and transmembrane structure disappeared with a little amount of PEG dosage. Pore size and mechanical strength tend to decrease with increasing PEG dosage up to 10 wt%. Glass transition temperature (Tg receded from 201.8 to 143.7°C for pure PSF and PSF/PEG with PEG dosage of 10 wt%. O2 and N2 gases permeation through the 10-minute plasma treated membranes tend to increase. However, the permeation strongly dispersed when treatment time was more extended.

  6. Study of a contracted glow in low-frequency plasma-jet discharges operating with argon

    Energy Technology Data Exchange (ETDEWEB)

    Minotti, F.; Giuliani, L.; Xaubet, M.; Grondona, D. [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, C1428EHA, Buenos Aires, Argentina and Instituto de Física del Plasma (INFIP), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires - UBA, C1428EHA, Buenos Aires (Argentina)

    2015-11-15

    In this work, we present an experimental and theoretical study of a low frequency, atmospheric plasma-jet discharge in argon. The discharge has the characteristics of a contracted glow with a current channel of submillimeter diameter and a relatively high voltage cathode layer. In order to interpret the measurements, we consider the separate modeling of each region of the discharge: main channel and cathode layer, which must then be properly matched together. The main current channel was modeled, extending a previous work, as similar to an arc in which joule heating is balanced by lateral heat conduction, without thermal equilibrium between electrons and heavy species. The cathode layer model, on the other hand, includes the emission of secondary electrons by ion impact and by additional mechanisms, of which we considered emission due to collision of atoms excited at metastable levels, and field-enhanced thermionic emission (Schottky effect). The comparison of model and experiment indicates that the discharge can be effectively sustained in its contracted form by the secondary electrons emitted by collision of excited argon atoms, whereas thermionic emission is by far insufficient to provide the necessary electrons.

  7. Studies on gas breakdown in pulsed radio frequency atmospheric pressure glow discharges

    Science.gov (United States)

    Huo, W. G.; Jian, S. J.; Yao, J.; Ding, Z. F.

    2014-05-01

    In pulsed RF atmospheric pressure glow discharges, the gas breakdown judged by the rapid drop in the amplitude of the pulsed RF voltage is no longer universally true. The steep increment of the plasma-absorbed RF power is proposed to determine the gas breakdown. The averaged plasma-absorbed RF power over a pulse period is used to evaluate effects of the preceding pulsed RF discharge on the breakdown voltage of the following one, finding that the breakdown voltage decreases with the increment in the averaged plasma-absorbed RF power under constant pulse duty ratio. Effects of the pulse off-time on the breakdown voltage and the breakdown delay time are also studied. The obtained dependence of the breakdown voltage on the pulse off-time is indicative of the transitional plasma diffusion processes in the afterglow. The breakdown voltage varies rapidly as the plasma diffuses fast in the region of moderate pulse off-time. The contribution of nitrogen atom recombination at the alumina surface is demonstrated in the prolonged memory effect on the breakdown delay time vs. the pulse off-time and experimentally validated by introducing a trace amount of nitrogen into argon at short and long pulse off-times.

  8. Conditioning of SST-1 Tokamak Vacuum Vessel by Baking and Glow Discharge Cleaning

    International Nuclear Information System (INIS)

    Khan, Ziauddin; George, Siju; Semwal, Pratibha; Dhanani, Kalpeshkumar R.; Pathan, Firozkhan S.; Paravastu, Yuvakiran; Raval, Dilip C.; Babu, Gattu Ramesh; Khan, Mohammed Shoaib; Pradhan, Subrata

    2016-01-01

    Highlights: • SST-1 Tokamak was successfully commissioned. • Vacuum vessel was pumped down to 4.5 × 10 –8 mbar after baking and continuous GDC. • GDC reduced the water vapour by additional 57% while oxygen was reduced by 50%. • Under this condition, an initial plasma breakdown with current of 40 kA for 75 ms was achieved. - Abstract: Steady-state Superconducting Tokamak (SST-1) vacuum vessel (VV) adopts moderate baking at 110 ± 10 °C and the limiters baking at 250 ± 10 °C for ∼ 200 h followed by glow discharge cleaning in hydrogen (GDC-H) with 0.15 A/m 2 current density towards its conditioning prior to plasma discharge experiment. The baking in SST-1 reduces the water (H 2 O) vapor by 95% and oxygen (O 2 ) by 60% whereas the GDC reduces the water vapor by an additional 57% and oxygen by another 50% as measured with residual gas analyzer. The minimum breakdown voltage for H-GDC in SST-1 tokamak was experimentally observed to 300 V at 8 mbar cm. As a result of these adherences, SST-1 VV achieves an ultimate of 4.5 × 10 −8 mbar with two turbo-molecular pumps with effective pumping speed of 3250 l/s. In the last campaign, SST-1 has achieved successful plasma breakdown, impurity burn through and a plasma current of ∼ 40 kA for 75 ms.

  9. Experimental and theoretical study of dissociation in the positive column of a hydrogen glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Amorim, J. [Departamento de Fisica, Instituto Tecnologico de Aeronautica, Centro Tecnico Aeroespacial, 12228-900 Sao Jose dos Campos (Brazil); Loureiro, J. [Centro de Electrodinamica da Universidade Tecnica de Lisboa, Instituto Superior Tecnico, 1096 Lisboa Codex (Portugal); Baravian, G.; Touzeau, M. [Laboratoire de Physique des Gaz et des Plasmas, URA 73 CNRS, Bat. 212, Universite Paris Sud, 91405 Orsay (France)

    1997-09-01

    The positive column of a hydrogen glow discharge was studied under typical operating conditions: gas pressure from 0.3 up to 5.0 Torr and discharge current from 1 up to 50 mA. Optical emission spectroscopy, optical absorption spectroscopy, and laser induced fluorescence have been employed in order to determine the gas temperature (300{lt}T{sub g}{lt}600K), the density of ground state hydrogen atoms (10{sup 12}{lt}[H(1s)]{lt}10{sup 13}cm{sup {minus}3}), and the kinetic temperature of H atoms (336{lt}T{sub a}{lt}1600K), respectively. Langmuir probes were utilized to measure the electric field (8{lt}E{lt}61Vcm{sup {minus}1}) in the positive column. A kinetic model based on the solutions to the homogeneous electron Boltzmann equation coupled to a set of rate balance equations for the vibrational levels H{sub 2}(X{sup 1}{Sigma}{sub g}{sup +},v), H atoms, and H{sup {minus}} ions was developed in order to predict the concentrations of these species. From a comparison between the measured and calculated concentrations of H atoms, the reassociation probability on the wall, in Pyrex glass, is estimated to be {congruent}10{sup {minus}2}. {copyright} {ital 1997 American Institute of Physics.}

  10. A study of the glow discharge plasma jet of the novel Hamburger-electrode

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wenzheng, E-mail: wzhliu@bjtu.edu.cn; Ma, Chuanlong, E-mail: 15121452@bjtu.edu.cn; Yang, Xiao; Cui, Weisheng; Chen, Xiuyang [School of Electrical Engineering, Beijing Jiaotong University, Beijing 100044 (China)

    2016-08-15

    To generate atmospheric pressure glow discharge plasma jets (APGDPJs), a novel Hamburger-electrode was proposed. Through the study on electric field distributions, flow field distributions, and characteristics of the discharge and jet, we found that adopting the mode of dielectric barrier discharge with non-uniform thickness of dielectric, it was easy to form the strong electric field areas which were conducive to generate discharge and electric field distributions with large electric field intensity in the narrow gap and weak electric field intensity in the wide gap that were not inclined to form a filament discharge. Using the structure of evenly distributed inner electrodes, it was easy to weaken the pressure of strong electric field areas and form flow field distributions which is beneficial for taking out the high density charged particles and generating APGDPJs. Stable APGDPJs in nitrogen with 3.5 mm in diameter and 9 mm in length were formed by using the novel Hamburger-electrode.

  11. Application of Glow Discharge Plasma to Alter Surface Properties of Materials

    Science.gov (United States)

    Trigwell, Steve; Buhler, Charles R.; Calle, Carlos I.

    2005-01-01

    Some polymer materials that are considered important for spaceport operations are rendered noncompliant when subjected to the Kennedy Space Center (KSC) Standard electrostatic testing. These materials operate in stringent environmental conditions, such as high humidity. Treating materials that fail electrostatic testing and altering their surface properties so that they become compliant would result in considerable cost savings. Significant improvement in electrostatic dissipation of Saf-T-Vu PVC after treatment with air Atmospheric Plasma Glow Discharge (APGD) was observed and the material now passed the KSC electrostatic test. The O:C ratio on the surface, as monitored by X-ray Photoelectron Spectroscopy, increased from 0.165 tO 0.275 indicating enhanced oxidation, and surface contact angle measurements decreased from 107.5 to 72.6 showing increased hydrophilicity that accounted for the increased conductivity. Monitoring of the aging showed that the materials hydrophobic recovery resulted in it failing the electrostatic test 30 hours after treatment. This was probably due to the out-diffusion of the added Zn, Ba, and Cd salt stabilizers detected on the surface and/or diffusion of low molecular weight oligomers. On going work includes improving the long term hydrophilicity by optimizing the APGD process with different gas mixtures. Treatment of other spaceport materials is also presented.

  12. Investigation into the analytical utility of plasma etching in reactive glow discharge plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Barshick, C.M. [Chemical and Analytical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6375 (United States); Zook, A.L. [Department of Chemistry, Franklin and Marshall College, Lancaster, Pennsylvania 17604 (United States)] Steiner, R.E. [Nuclear Materials Technoloy Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] King, F.L. [Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506-6045 (United States)

    1999-01-01

    Tetrafluoromethane (CF{sub 4}, 1.01{percent} by weight) was added to the argon support gas of a hollow cathode glow discharge to investigate the analytical utility of etch atomization. When a conducting copper cathode was analyzed, the sputtering rate (as measured by weight loss) was reduced by a factor of five compared to operation with pure argon. Copper atomic absorbance and copper atomic emission intensity were also reduced by factors of seven and two, respectively. When a nonconducting sample was analyzed, the stainless steel ring that held the sample acted as an auxiliary cathode, supporting the discharge processes. Radical fluoride species formed in this discharge reacted with the nonconducting substrate (silica) to produce volatile SiF{sub 4} that spontaneously evolved into the gas phase, carrying with it copper and uranium. This approach is analogous to plasma etching, a well-established technique for semiconductor processing. Atomic emission data were obtained with a pure argon discharge and an argon/CF{sub 4} discharge. With the addition of CF{sub 4}, a 30{percent} enhancement was observed for uranium in glass and a 50{percent} enhancement for copper in glass. Scanning electron microscopy (SEM) was used to support the supposition that etching of the silica matrix on the inner surface of the hollow cathode contributed to this enhancement. {copyright} {ital 1999} {ital Society for Applied Spectroscopy}

  13. UN{sub 2−x} layer formed on uranium metal by glow plasma nitriding

    Energy Technology Data Exchange (ETDEWEB)

    Long, Zhong [China Academy of Engineering Physics, P.O. Box 919-71, Mianyang 621907 (China); Hu, Yin [Science and Technology on Surface Physics and Chemistry Laboratory, P.O. Box 718-35, Mianyang 621907 (China); Chen, Lin [China Academy of Engineering Physics, P.O. Box 919-71, Mianyang 621907 (China); Luo, Lizhu [Science and Technology on Surface Physics and Chemistry Laboratory, P.O. Box 718-35, Mianyang 621907 (China); Liu, Kezhao, E-mail: liukz@hotmail.com [Science and Technology on Surface Physics and Chemistry Laboratory, P.O. Box 718-35, Mianyang 621907 (China); Lai, Xinchun, E-mail: lai319@yahoo.com [Science and Technology on Surface Physics and Chemistry Laboratory, P.O. Box 718-35, Mianyang 621907 (China)

    2015-01-25

    Highlights: • We used a very simple method to prepare nitride layer on uranium metal surface. • This modified layer is nitrogen-rich nitride, which should be written as UN{sub 2−x}. • TEM images show the nitride layer is composed of nano-sized grains. • XPS analysis indicates there is uranium with abnormal low valence in the nitride. - Abstract: Glow plasma nitriding is a simple and economical surface treatment method, and this technology was used to prepare nitride layer on the surface of uranium metal with thickness of several microns. The composition and structure of the nitride layer were analyzed by AES and XRD, indicating that this modified layer is nitrogen-rich uranium nitride, which should be written as UN{sub 2−x}. TEM images show the nitride layer is composed of nano-sized grains, with compact structure. And XPS analysis indicates there is uranium with abnormal low valence existing in the nitride. After the treated uranium storage in air for a long time, oxygen just entered the surface several nanometers, showing the nitride layer has excellent oxidation resistance. The mechanism of nitride layer formation and low valence uranium appearance is discussed.

  14. Auxiliary glow discharge in the trigger unit of a hollow-cathode thyratron

    Energy Technology Data Exchange (ETDEWEB)

    Korolev, Yu. D.; Landl, N. V., E-mail: landl@lnp.hcei.tsc.ru; Geyman, V. G.; Frants, O. B.; Shemyakin, I. A.; Nekhoroshev, V. O. [Russian Academy of Sciences, Institute of High-Current Electronics, Siberian Branch (Russian Federation)

    2016-08-15

    Results from studies of a low-current glow discharge with a hollow cathode are presented. A specific feature of the discharge conditions was that a highly emissive tablet containing cesium carbonate was placed in the cathode cavity. In the absence of a tablet, the discharge ignition voltage was typically ≥3.5 kV, while the burning voltage was in the range of 500–600 V. The use of the tablet made it possible to decrease the ignition voltage to 280 V and maintain the discharge burning voltage at a level of about 130 V. A model of the current sustainment in a hollow-cathode discharge is proposed. Instead of the conventional secondary emission yield, the model uses a generalized emission yield that takes into account not only ion bombardment of the cathode, but also the emission current from an external source. The model is used to interpret the observed current−voltage characteristics. The results of calculations agree well with the experimental data. It is shown that, in some discharge modes, the external emission current from the cathode can reach 25% of the total discharge current.

  15. Contact glow discharge electrolysis: its origin, plasma diagnostics and non-faradaic chemical effects

    Science.gov (United States)

    Gupta, Susanta K. Sen

    2015-12-01

    Contact glow discharge electrolysis (CGDE) also termed plasma electrolysis is a novel electrolysis where a stable sheath of light emitting plasma develops around an electrode immersed well inside a relatively high-conductivity liquid electrolyte during normal electrolysis (NE) at several hundred volts. The phenomenon may develop in dc-, pulsed dc-, ac- as well as RF-driven electrolyses. The chemical effects of CGDE are remarkably non-faradaic in respect to the nature of the products as well as their yields. The article traces comprehensively the progress made in studies of CGDE in aqueous and non-aqueous solutions since 1844 and reviews the developments in the understanding of its origin, light emission, plasma state and non-faradaic effects leading to the elucidation of detailed mechanism of the origin of CGDE on the basis of the onset of hydrodynamic instabilities in local vaporization of the solvent near the working electrode during NE, and that of highly non-faradaic effects of CGDE based on a model of two reaction zones located within the electrode plasma and at the plasma-liquid interface producing solvent derived radicals at high local concentrations. Keeping in view the recent surge of interest in varied applications of CGDE, the article is appended with highlights of these applications across synthetic chemistry, waste water treatment, electrosurgical devices, nanoparticle fabrications, surface engineering and micro-machining.

  16. Study of glow discharge positive column with cloud of disperse particles

    International Nuclear Information System (INIS)

    Polyakov, D.N.; Shumova, V.V.; Vasilyak, L.M.; Fortov, V.E.

    2011-01-01

    The study aims to describe plasma parameters changes induced by clouds of disperse micron size particles. Dust clouds were formed in the positive column of glow discharge in air at pressure 0.1-0.6 torr and current 0.1-3 mA. The simultaneous registration of discharge voltage and dust cloud parameters was carried out. Experimental results were simulated using diffusion model. The dust cloud is shown to smooth the radial electron concentration profile, increase electric field strength and electron temperature and stabilize the discharge. The cloud is demonstrated to be a trap for positive ions without increase of discharge current. -- Highlights: → 25% increase of longitudinal electric field strength in discharge with dust cloud. → The smoothing effect of dust cloud on radial electron and ion concentration profiles. → Dust cloud as a trap for positive ions without increase of discharge current. → Increase of electron temperature in discharge with dust cloud. → Increase of discharge stability in presence of dust cloud.

  17. The European lesser glow worm, Phosphaenus hemipterus (Goeze, in North America (Coleoptera, Lampyridae

    Directory of Open Access Journals (Sweden)

    Christopher Majka

    2009-12-01

    Full Text Available Phosphaenus hemipterus (Goeze is a Palaearctic glow worm (Coleoptera: Lampyridae, previously been reported in North America on the basis of two specimens; one collected in 1947 in Yarmouth, Nova Scotia; the other in 1989 in Montreal, Quebec. The present study newly records it from three sites in Halifax, Nova Scotia. One hundred and twenty six adult males and larvae were collected in 2009 in disturbed urban grassland areas, similar to habitats in England and Belgium where the species has been investigated. Experiments confirm that larvae feed on earthworms (Lumbricus terrestris, consistent with observations in Europe. The habitat is described, including vegetation, potential predators, and prey. Although ballast-shipments have previously been proposed as a vector for the species’ introduction to North America, the present study suggests that the importation of agricultural and horticultural products, which has lead to the introduction of many earthworms to the continent, could also serve as a conduit for the introduction of obligate earthworm predators such as the larvae of P. hemipterus. Although an adventive species, possible conservation concerns are discussed for a species that is considered endangered in parts of its native range.

  18. [Review] Polarization and Polarimetry

    Science.gov (United States)

    Trippe, Sascha

    2014-02-01

    Polarization is a basic property of light and is fundamentally linked to the internal geometry of a source of radiation. Polarimetry complements photometric, spectroscopic, and imaging analyses of sources of radiation and has made possible multiple astrophysical discoveries. In this article I review (i) the physical basics of polarization: electromagnetic waves, photons, and parameterizations; (ii) astrophysical sources of polarization: scattering, synchrotron radiation, active media, and the Zeeman, Goldreich-Kylafis, and Hanle effects, as well as interactions between polarization and matter (like birefringence, Faraday rotation, or the Chandrasekhar-Fermi effect); (iii) observational methodology: on-sky geometry, influence of atmosphere and instrumental polarization, polarization statistics, and observational techniques for radio, optical, and X/γ wavelengths; and (iv) science cases for astronomical polarimetry: solar and stellar physics, planetary system bodies, interstellar matter, astrobiology, astronomical masers, pulsars, galactic magnetic fields, gamma-ray bursts, active galactic nuclei, and cosmic microwave background radiation.

  19. Polar ionospheric responses to solar wind IMF changes

    Directory of Open Access Journals (Sweden)

    Y. Zhang

    Full Text Available Auroral and airglow emissions over Eureka (89° CGM during the 1997-98 winter show striking variations in relation to solar wind IMF changes. The period January 19 to 22, 1998, was chosen for detailed study, as the IMF was particularly strong and variable. During most of the period, Bz was northward and polar arcs were observed. Several overpasses by DMSP satellites during the four day period provided a clear picture of the particle precipitation producing the polar arcs. The spectral character of these events indicated excitation by electrons of average energy 300 to 500 eV. Only occasionally were electrons of average energy up to ~1 keV observed and these appeared transitory from the ground optical data. It is noted that polar arcs appear after sudden changes in IMF By, suggesting IMF control over arc initiation. When By is positive there is arc motion from dawn to dusk, while By is negative the motion is consistently dusk to dawn. F-region (anti-sunward convections were monitored through the period from 630.0 nm emissions. The convection speed was low (100-150 m/s when Bz was northward but increased to 500 m/s after Bz turned southward on January 20.

    Key words: Atmospheric composition and structure (airglow and aurora - Ionosphere (particle precipitation - Magnetospheric Physics (polar cap phenomena

  20. Polarization feedback laser stabilization

    Science.gov (United States)

    Esherick, P.; Owyoung, A.

    1987-09-28

    A system for locking two Nd:YAG laser oscillators includes an optical path for feeding the output of one laser into the other with different polarizations. Elliptical polarization is incorporated into the optical path so that the change in polarization that occurs when the frequencies coincide may be detected to provide a feedback signal to control one laser relative to the other. 4 figs.