WorldWideScience

Sample records for gem-based gas amplification

  1. A novel self-supporting GEM-based amplification structure for a time projection chamber at the ILC

    Energy Technology Data Exchange (ETDEWEB)

    Behnke, Ties; Diener, Ralf; Rosemann, Christoph; Steder, Lea

    2012-11-15

    In this paper, a new self-supporting way to mount Gas Electron Multipliers is presented. It has been developed to provide a method to cover large readout areas while ensuring the flatness of the foils and keeping the amount of dead material minimal. The structure has been tested in a Time Projection Chamber prototype, using cosmic muon tracks. The impact of the mounting structure on the track reconstruction and the single point resolution is quantified and its impact on the tracking efficiency and dE/dx measurements is estimated.

  2. Characterization of a GEM-based scintillation detector with He-CF4 gas mixture in clinical proton beams

    Science.gov (United States)

    Nichiporov, D.; Coutinho, L.; Klyachko, A. V.

    2016-04-01

    Accurate, high-spatial resolution dosimetry in proton therapy is a time consuming task, and may be challenging in the case of small fields, due to the lack of adequate instrumentation. The purpose of this work is to develop a novel dose imaging detector with high spatial resolution and tissue equivalent response to dose in the Bragg peak, suitable for beam commissioning and quality assurance measurements. A scintillation gas electron multiplier (GEM) detector based on a double GEM amplification structure with optical readout was filled with a He/CF4 gas mixture and evaluated in pristine and modulated proton beams of several penetration ranges. The detector’s performance was characterized in terms of linearity in dose rate, spatial resolution, short- and long-term stability and tissue-equivalence of response at different energies. Depth-dose profiles measured with the GEM detector in the 115-205 MeV energy range were compared with the profiles measured under similar conditions using the PinPoint 3D small-volume ion chamber. The GEM detector filled with a He-based mixture has a nearly tissue equivalent response in the proton beam and may become an attractive and efficient tool for high-resolution 2D and 3D dose imaging in proton dosimetry, and especially in small-field applications.

  3. Cosmic ray tests of a GEM-based TPC prototype operated in Ar–CF{sub 4}–isobutane gas mixtures: II

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, M., E-mail: makoto.kobayashi.exp@kek.jp [High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801 (Japan); Yonamine, R. [Graduate University for Advanced Studies, KEK, Tsukuba 305-0801 (Japan); Tomioka, T. [Tokyo University of Agriculture and Technology, Koganei 184-8588 (Japan); Aoza, A. [Saga University, Saga 840-8502 (Japan); Bito, H. [Tokyo University of Agriculture and Technology, Koganei 184-8588 (Japan); Fujii, K. [High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801 (Japan); Higashi, T. [Saga University, Saga 840-8502 (Japan); Hiramatsu, K. [Kinki University, Higashi-Osaka 577-8502 (Japan); Ikematsu, K. [High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801 (Japan); Ishikawa, A. [Saga University, Saga 840-8502 (Japan); Kato, Y. [Kinki University, Higashi-Osaka 577-8502 (Japan); Kuroiwa, H. [Saga University, Saga 840-8502 (Japan); Matsuda, T. [High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801 (Japan); Nitoh, O.; Ohta, H.; Sakai, K. [Tokyo University of Agriculture and Technology, Koganei 184-8588 (Japan); Settles, R.D. [Max Planck Institute for Physics, DE-80805 Munich (Germany); Sugiyama, A.; Tsuji, H. [Saga University, Saga 840-8502 (Japan); Watanabe, T. [Kogakuin University, Hachioji 192-0015 (Japan); and others

    2014-12-11

    The spatial resolution along the pad-row direction was measured with a GEM-based TPC prototype for the future linear collider experiment in order to understand its performance for tracks with finite projected angles with respect to the pad-row normal. The degradation of the resolution due to the angular pad effect was confirmed to be consistent with the prediction of a simple calculation taking into account the cluster-size distribution and the avalanche fluctuation.

  4. The PANDA GEM-based TPC prototype

    Energy Technology Data Exchange (ETDEWEB)

    Fabbietti, L., E-mail: laura.fabbietti@ph.tum.d [Excellence Cluster ' Universe' , Technische Universitaet Muenchen, Boltztmannstr. 2, Garching bei Muenchen 85748 (Germany); Angerer, H. [Physik Department E18, Technische Universitaet Muenchen, 85748 Muenchen (Germany); Arora, R. [Detektor Labor des GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Beck, R. [Helmholtz-Institut fuer Strahlen- und Kernphysik, 53115 Bonn (Germany); Berger, M. [Excellence Cluster ' Universe' , Technische Universitaet Muenchen, Boltztmannstr. 2, Garching bei Muenchen 85748 (Germany); Buehler, P.; Cargnelli, M. [Stefan-Meyer Institute fuer subatomare Physik, 1090 Vienna (Austria); Doerheim, S. [Physik Department E18, Technische Universitaet Muenchen, 85748 Muenchen (Germany); Hehner, J. [Detektor Labor des GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Herrmann, N. [FOPI Collaboration, GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Hoeppner, C. [Physik Department E18, Technische Universitaet Muenchen, 85748 Muenchen (Germany); Kaiser, D. [Helmholtz-Institut fuer Strahlen- und Kernphysik, 53115 Bonn (Germany); Ketzer, B. [Physik Department E18, Technische Universitaet Muenchen, 85748 Muenchen (Germany); Mladen, K. [FOPI Collaboration, GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Kleipa, V. [Detektor Labor des GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Konorov, I. [Physik Department E18, Technische Universitaet Muenchen, 85748 Muenchen (Germany); Kunkel, J. [Detektor Labor des GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Lalik, R. [Excellence Cluster ' Universe' , Technische Universitaet Muenchen, Boltztmannstr. 2, Garching bei Muenchen 85748 (Germany); Lang, M. [Helmholtz-Institut fuer Strahlen- und Kernphysik, 53115 Bonn (Germany)

    2011-02-01

    We report on the development of a GEM-based TPC detector prototype for the PANDA experiment. The design and requirements of this device will be illustrated, with particular emphasis on the properties of the recently tested GEM-detector, the characterization of the read-out electronics and the development of the tracking software that allows to evaluate the GEM-TPC data.

  5. A Time Projection Chamber with GEM-Based Readout

    CERN Document Server

    Attié, David; Bellerive, Alain; Bezshyyko, Oleg; Bhattacharya, Deb Sankar; Bhattacharya, Purba; Bhattacharya, Sudeb; Caiazza, Stefano; Colas, Paul; De Lentdecker, Gilles; Dehmelt, Klaus; Desch, Klaus; Diener, Ralf; Dixit, Madhu; Fleck, Ivor; Fujii, Keisuke; Fusayasu, Takahiro; Ganjour, Serguei; Gao, Yuanning; Gros, Philippe; Hayman, Peter; Hedberg, Vincent; Ikematsu, Katsumasa; Jönsson, Leif; Kaminski, Jochen; Kato, Yukihiro; Kawada, Shin-ichi; Killenberg, Martin; Kleinwort, Claus; Kobayashi, Makoto; Krylov, Vladyslav; Li, Bo; Li, Yulan; Lundberg, Björn; Lupberger, Michael; Majumdar, Nayana; Matsuda, Takeshi; Mehdiyev, Rashid; Mjörnmark, Ulf; Müller, Felix; Münnich, Astrid; Mukhopadhyay, Supratik; Ogawa, Tomohisa; Oskarsson, Anders; Österman, Lennart; Peterson, Daniel; Riallot, Marc; Rosemann, Christoph; Roth, Stefan; Schade, Peter; Schäfer, Oliver; Settles, Ronald Dean; Shirazi, Amir Noori; Smirnova, Oxana; Sugiyama, Akira; Takahashi, Tohru; Tian, Junping; Timmermans, Jan; Titov, Maksym; Tsionou, Dimitra; Vauth, Annika; Wang, Wenxin; Watanabe, Takashi; Werthenbach, Ulrich; Yang, Yifan; Yang, Zhenwei; Yonamine, Ryo; Zenker, Klaus; Zhang, Fan

    2016-01-01

    For the International Large Detector concept at the planned International Linear Collider, the use of time projection chambers (TPC) with micro-pattern gas detector readout as the main tracking detector is investigated. In this paper, results from a prototype TPC, placed in a 1 T solenoidal field and read out with three independent GEM-based readout modules, are reported. The TPC was exposed to a 6 GeV electron beam at the DESY II synchrotron. The efficiency for reconstructing hits, the measurement of the drift velocity, the space point resolution and the control of field inhomogeneities are presented.

  6. 3D simulation of electron and ion transmission of GEM-based detectors

    Science.gov (United States)

    Bhattacharya, Purba; Mohanty, Bedangadas; Mukhopadhyay, Supratik; Majumdar, Nayana; da Luz, Hugo Natal

    2017-10-01

    Time Projection Chamber (TPC) has been chosen as the main tracking system in several high-flux and high repetition rate experiments. These include on-going experiments such as ALICE and future experiments such as PANDA at FAIR and ILC. Different R&D activities were carried out on the adoption of Gas Electron Multiplier (GEM) as the gas amplification stage of the ALICE-TPC upgrade version. The requirement of low ion feedback has been established through these activities. Low ion feedback minimizes distortions due to space charge and maintains the necessary values of detector gain and energy resolution. In the present work, Garfield simulation framework has been used to study the related physical processes occurring within single, triple and quadruple GEM detectors. Ion backflow and electron transmission of quadruple GEMs, made up of foils with different hole pitch under different electromagnetic field configurations (the projected solutions for the ALICE TPC) have been studied. Finally a new triple GEM detector configuration with low ion backflow fraction and good electron transmission properties has been proposed as a simpler GEM-based alternative suitable for TPCs for future collider experiments.

  7. Performances of a GEM-based Time Projection Chamber prototype for the AMADEUS experiment

    CERN Document Server

    Lener, M Poli; Corradi, G; Curceanu, C; D'Uffizi, A; Paglia, C; Vidal, A Romero; Sbardella, E; Scordo, A; Tagnani, D; Zmeskal, J

    2013-01-01

    A large number of high-energy and heavy-ion experiments successfully used Time Projection Chamber (TPC) as central tracker and particle identification detector. However, the performance requirements on TPC for new high-rate particle experiments greatly exceed the abilities of traditional TPC read out by multi-wire proportional chamber (MWPC). Gas Electron Multiplier (GEM) detector has great potential to improve TPC performances when used as amplification device. In this paper we present the R&D activity on a new GEM-based TPC detector built as a prototype for the inner part for AMADEUS, a new experimental proposal at the DAFNE collider at Laboratori Nazionali di Frascati (INFN), aiming to perform measurements of the low-energy negative kaons interactions in nuclei. In order to evaluate the GEM-TPC performances, a 10x10 cm2 prototype with a drift gap up to 15 cm has been realized. The detector was tested at the pM1 beam facility of the Paul Scherrer Institut (PSI) with low momentum pions and protons, witho...

  8. GEM-based TPC with CCD imaging for directional dark matter detection

    Science.gov (United States)

    Phan, N. S.; Lauer, R. J.; Lee, E. R.; Loomba, D.; Matthews, J. A. J.; Miller, E. H.

    2016-11-01

    The most mature directional dark matter experiments at present all utilize low-pressure gas Time Projection Chamber (TPC) technologies. We discuss some of the challenges for this technology, for which balancing the goal of achieving the best sensitivity with that of cost effective scale-up requires optimization over a large parameter space. Critical for this are the precision measurements of the fundamental properties of both electron and nuclear recoil tracks down to the lowest detectable energies. Such measurements are necessary to provide a benchmark for background discrimination and directional sensitivity that could be used for future optimization studies for directional dark matter experiments. In this paper we describe a small, high resolution, high signal-to-noise GEM-based TPC with a 2D CCD readout designed for this goal. The performance of the detector was characterized using alpha particles, X-rays, gamma-rays, and neutrons, enabling detailed measurements of electron and nuclear recoil tracks. Stable effective gas gains of greater than 1 × 105 were obtained in 100 Torr of pure CF4 by a cascade of three standard CERN GEMs each with a 140 μm pitch. The high signal-to-noise and sub-millimeter spatial resolution of the GEM amplification and CCD readout, together with low diffusion, allow for excellent background discrimination between electron and nuclear recoils down below ∼10 keVee (∼23 keVr fluorine recoil). Even lower thresholds, necessary for the detection of low mass WIMPs for example, might be achieved by lowering the pressure and utilizing full 3D track reconstruction. These and other paths for improvements are discussed, as are possible fundamental limitations imposed by the physics of energy loss.

  9. Characterization of a GEM-based fast neutron detector

    Energy Technology Data Exchange (ETDEWEB)

    Esposito, B., E-mail: basilio.esposito@enea.it [Associazione Euratom-ENEA sulla Fusione, Via E. Fermi, 45, I-00044 Frascati, Roma (Italy); Marocco, D.; Villari, R. [Associazione Euratom-ENEA sulla Fusione, Via E. Fermi, 45, I-00044 Frascati, Roma (Italy); Murtas, F. [Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare, Via E. Fermi, 40, I-00044 Frascati, Roma (Italy); Rodionov, R. [SRC RF TRINITI Troitsk, Moscow (Russian Federation)

    2014-03-21

    The neutron efficiency of a Gas Electron Multiplier (GEM)-based detector designed for fast neutron measurements in fusion devices was determined through the combined use of Monte Carlo (MCNPX) calculations and analysis of deuterium–deuterium and deuterium–tritium neutron irradiation experiments. The detector, characterized by a triple GEM structure flushed with a Ar/CO{sub 2}/CF{sub 4} – 45/15/40 gas mixture, features a digital read-out system and has two sub-units for the detection of 2.5+14 MeV neutrons and 14 MeV neutrons (U{sub DD} and U{sub DT}, respectively). The pulse height spectra (PHS) determined from the curves of experimental efficiency as a function of the detector's high voltage (HV) and the MCNPX-simulated PHS were compared using a fitting routine that finds the best match between the experimental and simulated PHS by assuming a parametric model for the relation between HV (that determines the detector's gain) and the energy deposited in the gas. This led to express the experimental neutron efficiency as a function of the discrimination level set on the deposited energy (energy threshold). The detector sensitivity to γ-rays was also analyzed and the operational range in which the γ-ray contribution to the signal is not negligible was determined. It is found that this detector can reach a maximum neutron efficiency of ∼1×10{sup −3} counts/n at 2.5 MeV (U{sub DD} sub-unit) and of ∼4×10{sup −3} counts/n at 14 MeV (U{sub DT} and U{sub DD} sub-units)

  10. Building a large-area GEM-based readout chamber for the upgrade of the ALICE TPC

    CERN Document Server

    Gasik, Piotr

    2016-01-01

    A large Time Projection Chamber (TPC) is the main device for tracking and charged-particle identification in the ALICE experiment at the CERN LHC. After the second long shutdown in 2019-2020, the LHC will deliver Pb beams colliding at an interaction rate up to 50 kHz, which is about a factor of 100 above the present read-out rate of the TPC. To fully exploit the LHC potential the TPC will be upgraded based on the Gas Electron Multiplier (GEM) technology. A prototype of an ALICE TPC Outer Read-Out Chamber (OROC) was equipped with twelve large-size GEM foils as amplification stage to demonstrate the feasibility of replacing the current Multi Wire Proportional Chambers with the new technology. With a total area of $\\sim$0.76 m$^2$ it is the largest GEM-based detector built to date. The GEM OROC was installed within a test field cage and commissioned with radioactive sources.

  11. Building a large-area GEM-based readout chamber for the upgrade of the ALICE TPC

    Science.gov (United States)

    Gasik, P.

    2017-02-01

    A large Time Projection Chamber (TPC) is the main device for tracking and charged-particle identification in the ALICE experiment at the CERN LHC. After the second long shutdown in 2019-2020, the LHC will deliver Pb beams colliding at an interaction rate up to 50 kHz, which is about a factor of 100 above the present read-out rate of the TPC. To fully exploit the LHC potential the TPC will be upgraded based on the Gas Electron Multiplier (GEM) technology. A prototype of an ALICE TPC Outer Read-Out Chamber (OROC) was equipped with twelve large-size GEM foils as amplification stage to demonstrate the feasibility of replacing the current Multi Wire Proportional Chambers with the new technology. With a total area of ∼0.76 m2 it is the largest GEM-based detector built to date. The GEM OROC was installed within a test field cage and commissioned with radioactive sources.

  12. Study of electron focusing in thick GEM based photon detectors using semitransparent photocathodes

    Energy Technology Data Exchange (ETDEWEB)

    Baishali, G., E-mail: baishali@isu.iisc.ernet.in [Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore 560012 (India); Radhakrishna, V.; Koushal, V.; Rakhee, K. [Space Astronomy Group, ISRO Satellite Centre, Bangalore 560017 (India); Rajanna, K. [Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore 560012 (India)

    2013-11-21

    The detection efficiency of a GEM based UV sensitive gaseous photomultiplier (GPM) depends on the focusing of electrons from the drift gap to the GEM aperture. We have studied the effect of drift parameters on the efficiency of electron focusing into Thick GEM (THGEM) holes in a GPM with semitransparent UV photoconverter. This study comprises simulation of electron focusing into THGEM holes using GARFIELD for different Ar and Ne based gas mixtures and experimental investigations of the same with P10 gas mixture. -- Highlights: •Effect of drift parameters on detection efficiency of a THGEM based GPM is studied. •Drift parameters studied are drift field, drift gap, gas composition and pressure. •GARFIELD simulation on Electron Transfer Efficiency for various drift parameters. •Experimental studies were carried out for P10 gas at lower multiplication voltage. •Optimization of drift parameters for maximizing the detection efficiency.

  13. A GEM-based Time Projection Chamber for the AMADEUS experiment

    CERN Document Server

    Lener, M Poli; Corradi, G; Curceanu, C; D'Uffizi, A; Paglia, C; Sbardella, E; Scordo, A; Tagnani, D; Vidal, A Romero; Zmeskal, J

    2013-01-01

    In this paper we present the R&D activity on a new GEM-based TPC prototype for AMADEUS, a new experimental proposal at the DA{\\Phi}NE {\\Phi}-factory at the Laboratori Nazionali di Frascati (INFN), aiming to perform measurements of the low-energy negative kaons interactions in nuclei. Such innovative detector will equip the inner part of the experiment in order to perfom a better reconstruction of the primary vertex and the secondary particles tracking. A 10x10 cm2 prototype with a drift gap up to 15 cm was realized and succesfully tested at the {\\pi} M1 beam facility of the Paul Scherrer Institut (PSI) with low momentum hadrons. The measurements of the detector efficiency and spatial resolution have been performed. The results as a function of the gas gain, drift field, front-end electronic threshold and particle momentum are reported and discussed.

  14. Resolution studies of a GEM-based TPC

    Energy Technology Data Exchange (ETDEWEB)

    Killenberg, M.

    2006-12-15

    Currently there are four different concept studies trying to optimise the detector for the requirements at the ILC. In three of these detector concepts a time projection chamber (TPC) is foreseen as the main tracking device. To achieve the intended spatial resolution of 100 {mu}m, micro pattern gas detectors (MPGD) are considered for gas amplification. The two different MPGDs discussed for the ILC TPC are Micro-Mesh Gaseous Detectors (Micromegas) and Gas Electron Multiplier foils (GEMs). The current thesis shows resolution studies with a TPC prototype equipped with a triple GEM readout structure. A hodoscope made up of silicon strip sensors gives a precision reference track, allowing an unbiased measurement of the spatial resolution. High statistics measurements have been conducted at the DESY test beam facility, which provides positrons with a tunable energy between 1 GeV and 6 GeV. Using the independent measurement of the hodoscope allows systematic studies of the homogeneity of the TPC's electric field. The fluctuations of the field in the chamber's central region were found to be {delta}E/E=8.10{sup -3}. Field distortions have been determined and corrected, reducing the remaining deviations to a level well below the spatial resolution of the TPC. One important task is to reduce the number of ions drifting back into the sensitive volume. Special GEM settings with minimised ion backdrift have been examined with respect to their influence on the spatial resolution and it was found that the spatial resolution is not degraded using these special settings. The TPC prototype has been operated in a 4 T magnetic field, provided by a superconducting solenoid located at DESY Hamburg. Again the spatial resolution measured with the ion backdrift optimised settings is compared to that achieved with nonoptimised settings. In both cases the measured resolution is approximately 130 {mu}m. (orig.)

  15. Master curves for gas amplification in low vacuum and environmental scanning electron microscopy.

    Science.gov (United States)

    Thiel, Bradley L

    2004-02-01

    The concept of universal amplification profiles for gas cascade amplification of signals in low vacuum and environmental scanning electron microscopes is demonstrated both experimentally and theoretically using water vapor. For a given gas, cascade amplification gain profiles can be plotted onto a single master curve where the independent reduced parameter is the ratio of pressure to amplification field strength. When plotted in this fashion, both desired secondary electron and spurious background signal components fall onto respective master curves, with the amplitude being a function of anode bias only. These master curves can be described by simple Townsend Gas Capacitor equations using only two gas-specific parameters. As long as single scattering conditions apply, this approach allows for simplified, direct comparison of the gain characteristics of different gases and allows more intelligent selection of imaging conditions. The utility of treating signal amplification in this manner is demonstrated through a series of images collected under a variety of conditions, but with the ratio of pressure to amplification field strength kept constant. In practice, the range of operational parameter space in which this description can be applied to imaging is limited, as images typically have a mixture of secondary and backscattered contributions.

  16. Resonant amplification of quantum fluctuations in a spinor gas

    DEFF Research Database (Denmark)

    Topic, O.; Scherer, M.; Gebreyesus, G.;

    2010-01-01

    Bose-Einstein condensates of atoms with non-zero spin are known to constitute an ideal system to investigate fundamental properties of magnetic superfluids. More recently it was realized that they also provide the fascinating opportunity to investigate the macroscopic amplification of quantum and...... of seed atoms is triggered purely by quantum fluctuations and thus the system acts as a matter-wave amplifier for the vacuum state....

  17. GEM-based TPC with CCD Imaging for Directional Dark Matter Detection

    CERN Document Server

    Phan, N S; Lee, E R; Loomba, D; Matthews, J A J; Miller, E H

    2015-01-01

    Directional dark matter detection will require scale-ups to large volumes if low-pressure gas Time Projection Chambers (TPCs) are the only viable technology. We discuss some of the challenges for this technology, where balancing the goal of achieving the best sensitivity with that of cost effective scale-up requires an optimization over a large parameter space. Critical for this are the precision measurements of the fundamental properties of both electron and nuclear recoil tracks down to the lowest energies. Such measurements would provide a benchmark for background discrimination and directional sensitivity that could be used for future optimization studies for directional dark matter experiments. In this paper we describe a small, high resolution, high signal-to-noise GEM-based TPC with a 2D CCD readout designed for this goal. The performance of the detector was characterized using X-rays, gamma-rays, and neutrons, enabling detailed measurements of electron and nuclear recoil tracks. Stable effective gas g...

  18. A GEM-based dose imaging detector with optical readout for proton radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Klyachko, A.V., E-mail: aklyachk@indiana.edu [Indiana University Cyclotron Operations, Indiana University Integrated Science and Accelerator Technology Hall, 2401 Milo. B. Sampson Ln., Bloomington, IN 47408 (United States); Moskvin, V. [Department of Radiation Oncology, School of Medicine, Indiana University, Indianapolis, IN 46202 (United States); Nichiporov, D.F.; Solberg, K.A. [Indiana University Cyclotron Operations, Indiana University Integrated Science and Accelerator Technology Hall, 2401 Milo. B. Sampson Ln., Bloomington, IN 47408 (United States)

    2012-12-01

    New techniques in proton radiation therapy and advances in beam delivery systems design such as beam scanning require accurate 2D dosimetry systems to verify the delivered dose distribution. Dose imaging detectors based on gas electron multipliers (GEMs) are capable of providing high sensitivity, improved dose measurement linearity, position resolution, fast response and accurate characterization of depth-dose distributions. In this work, we report on the development of a GEM-based dose imaging detector with optical readout using a CCD camera. A 10 Multiplication-Sign 10 cm{sup 2} detector has been tested in a 205 MeV proton beam in single- and double-GEM configurations. The detector demonstrates linearity in dose rate up to 100 Gy/min and position resolution ({sigma}) of 0.42 mm. Transverse non-uniformity of the detector response is {<=}10% before correction and the stability of the detector output throughout the day is within {+-}1%, with day-to-day reproducibility of about 10%. The depth-dose response of the detector is close to that of a wide-aperture air-filled ionization chamber and is in good agreement with Monte Carlo simulations.

  19. Demonstration of resonant backward Raman amplification in high-density gas-jet plasma

    Science.gov (United States)

    Wu, Z. H.; Zhou, K. N.; Zheng, X. M.; Wei, X. F.; Zhu, Q. H.; Su, J. Q.; Xie, N.; Jiao, Z. H.; Peng, H.; Wang, X. D.; Sun, L.; Li, Q.; Huang, Z.; Zuo, Y. L.

    2016-10-01

    Backward Raman amplification was observed in a 0.7 mm-long high-density gas jet plasma. The 800 nm 30 fs seed pulse was amplified by a factor  ∼28, with an output energy of 2.8 mJ. The output spectra showed that the waveband around 800 nm was significantly amplified. The experimental result demonstrated that the resonant Raman amplification can be realized in high-density plasma against strong plasma instability.

  20. Four-Wave Optical Parametric Amplification in a Raman-Active Gas

    Directory of Open Access Journals (Sweden)

    Yuichiro Kida

    2015-08-01

    Full Text Available Four-wave optical parametric amplification (FWOPA in a Raman-active medium is experimentally investigated by use of an air-filled hollow fiber. A femtosecond pump pulse shorter than the period of molecular motion excites the coherent molecular motion of the Raman-active molecules during the parametric amplification of a signal pulse. The excited coherent motion modulates the frequency of the signal pulse during the parametric amplification, and shifts it to lower frequencies. The magnitude of the frequency redshift depends on the pump intensity, resulting in intensity-dependent spectral characteristics that are different from those in the FWOPA induced in a noble-gas-filled hollow fiber.

  1. Progress on the realization of a new GEM based neutron diagnostic concept for high flux neutron beams

    Science.gov (United States)

    Croci, G.; Rebai, M.; Cazzaniga, C.; Palma, M. Dalla; Grosso, G.; Muraro, A.; Murtas, F.; Claps, G.; Pasqualotto, R.; Cippo, E. Perelli; Tardocchi, M.; Tollin, M.; Cavenago, M.; Gorini, G.

    2014-08-01

    Fusion reactors will need high flux neutron detectors to diagnose the deuterium-deuterium and deuterium-tritium. A candidate detection technique is the Gas Electron Multiplier (GEM). New GEM based detectors are being developed for application to a neutral deuterium beam test facility. The proposed detection system is called Close-contact Neutron Emission Surface Mapping (CNESM). The diagnostic aims at providing the map of the neutron emission due to interaction of the deuterium beam with the deuterons implanted in the beam dump surface. This is done by placing a detector in close contact, right behind the dump. CNESM uses nGEM detectors, i.e. GEM detectors equipped with a cathode that also serves as neutron-proton converter foil. After the realization and test of several small area prototypes, a full size prototype has been realized and tested with laboratory sources. Test on neutron beams are foreseen for the next months.

  2. Progress on the realization of a new GEM based neutron diagnostic concept for high flux neutron beams

    Energy Technology Data Exchange (ETDEWEB)

    Croci, G.; Tardocchi, M. [Istituto di Fisica del Plasma, Associazione EURATOM-ENEA-CNR, Milano, Italy and INFN, Sez. di Milano-Bicocca, Milano (Italy); Rebai, M.; Cippo, E. Perelli; Gorini, G. [Dipartimento di Fisica, Università degli Studi di Milano-Bicocca, Milano, Italy and INFN, Sez. di Milano-Bicocca, Milano (Italy); Cazzaniga, C. [Dipartimento di Fisica, Università degli Studi di Milano-Bicocca, Milano (Italy); Palma, M. Dalla; Pasqualotto, R.; Tollin, M. [Consorzio RFX - Associazione Euratom-Enea sulla Fusione, Padova (Italy); Grosso, G.; Muraro, A. [Istituto di Fisica del Plasma, Associazione EURATOM-ENEA-CNR, Milano (Italy); Murtas, F.; Claps, G. [INFN, Laboratori Nazionali di Frascati, Frascati (Roma) (Italy); Cavenago, M. [INFN, Laboratori Nazionali di Legnaro, Legnaro (Padova) (Italy)

    2014-08-21

    Fusion reactors will need high flux neutron detectors to diagnose the deuterium-deuterium and deuterium-tritium. A candidate detection technique is the Gas Electron Multiplier (GEM). New GEM based detectors are being developed for application to a neutral deuterium beam test facility. The proposed detection system is called Close-contact Neutron Emission Surface Mapping (CNESM). The diagnostic aims at providing the map of the neutron emission due to interaction of the deuterium beam with the deuterons implanted in the beam dump surface. This is done by placing a detector in close contact, right behind the dump. CNESM uses nGEM detectors, i.e. GEM detectors equipped with a cathode that also serves as neutron-proton converter foil. After the realization and test of several small area prototypes, a full size prototype has been realized and tested with laboratory sources. Test on neutron beams are foreseen for the next months.

  3. Amplification, attenuation, and dispersion of sound in inhomogeneous flows. [of compressible gas

    Science.gov (United States)

    Kentzer, C. P.

    1975-01-01

    First order effects of gradients in nonuniform potential flows of a compressible gas are included in a dispersion relation for sound waves. Three nondimensional numbers, the ratio of the change in the kinetic energy in one wavelength to the thermal energy of the gas, the ratio of the change in the total energy in one wavelength to the thermal energy, and the ratio of the dilatation frequency (the rate of expansion per unit volume) to the acoustic frequency, play the dominant role permitting the separation of the effects of flow gradients into isotropic and anisotropic effects. Dispersion and attenuation (or amplification) of sound are proportional to the wavelength for small wavelength and depend on the direction of wave propagation relative to flow gradients. Modification of ray acoustics for the effects of flow gradients is suggested and conditions for amplification and attenuation of sound are discussed.

  4. Investigation of the light signal's amplification of the gas scintillator working in the electric field

    Energy Technology Data Exchange (ETDEWEB)

    Gorski, A.; Karpik-Piaskowska, K.; Malecki, H.; Stepinski, M. (Lodz Univ. (Poland). Inst. Fizyki)

    1980-01-01

    The apparature for the investigation of the properties of the gas scintillator is described. The gas scintillator is working in the electric field. We got the characteristics of the amplification's changes of the light signal of krypton in the function of the electric field's intensity for different values of the pressure of the used gas.

  5. Vacuum ultraviolet light source utilizing rare gas scintillation amplification sustained by photon positive feedback

    Science.gov (United States)

    Aprile, Elena (Inventor); Chen, Danli (Inventor)

    1995-01-01

    A source of light in the vacuum ultraviolet (VUV) spectral region includes a reflective UV-sensitive photocathode supported in spaced parallel relationship with a mesh electrode within a rare gas at low pressure. A high positive potential applied to the mesh electrode creates an electric field which causes drifting of free electrons occurring between the electrodes and producing continuous VUV light output by electric field-driven scintillation amplification sustained by positive photon feedback mediated by photoemission from the photocathode. In one embodiment the lamp emits a narrow-band continuum peaked at 175 nm.

  6. Amplification and Scintillation Properties of Oxygen-Rich Gas Mixtures for Optical-TPC Applications

    CERN Document Server

    Weissman, L; Chechik, R; Dangendorf, V; Gai, M; Tittelmeier, K; Weller, H R

    2006-01-01

    We studied electron amplification and light emission from avalanches in oxygen-containing gas mixtures. The mixtures investigated in this work included, among others, CO2 and N2O mixed with Triethylamine (TEA) or N2. Double-Step Parallel Gap (DSPG) multipliers and THick Gas Electron Multipliers (THGEM) were investigated. High light yields were measured from CO2+N2 and CO2+TEA, though with different emission spectra. We observed the characteristic wave-length emission of N2 and of TEA and used a polymer wave-length shifter to convert TEA UV-light into the visible spectrum. The results of these measurements indicate the applicability of optical recording of ionizing tracks in a TPC target-detector designed to study the cross section of the 16O(g,a)12C reaction, a central problem in nuclear astrophysics.

  7. Study of reconstruction methods for a time projection chamber with GEM gas amplification system

    Energy Technology Data Exchange (ETDEWEB)

    Diener, R.

    2006-12-15

    A new e{sup +}e{sup -} linear collider with an energy range up to 1TeV is planned in an international collaboration: the International Linear Collider (ILC). This collider will be able to do precision measurements of the Higgs particle and of physics beyond the Standard Model. In the Large Detector Concept (LDC) - which is one proposal for a detector at the ILC - a Time Projection Chamber (TPC) is foreseen as the main tracking device. To meet the requirements on the resolution and to be able to work in the environment at the ILC, the application of new gas amplification technologies in the TPC is necessary. One option is an amplification system based on Gas Electron Multipliers (GEMs). Due to the - in comparison with older technologies - small spatial width of the signals, this technology poses new requirements on the readout structures and the reconstruction methods. In this work, the performance and the systematics of different reconstruction methods have been studied, based on data measured with a TPC prototype in high magnetic fields of up to 4T and data from a Monte Carlo simulation. The latest results of the achievable point resolution are presented and their limitations have been investigated. (orig.)

  8. Gas amplification properties of GEM foils; Gasverstaerkungseigenschaften von GEM-Folien

    Energy Technology Data Exchange (ETDEWEB)

    Beck, Jeannine

    2009-01-15

    In the framework of the detector concept International Linear Detector for the future accelerator project International Linear Collider, in which electrons and positrons at c. m. energies of 500 GeV are brought to collision, a time projection chamber shall be applied as central track detector. By the application of such a chamber as track detector a three-dimensional reconstruction of the track points is possible. If a particle passes the gas volume within the chamber it ionizises single gas atoms and the arising electrons move after the amplification in the GEM arrangement to the anode, so that a two-dimensional projection of the particle track is possible. The third dimension is calculated from the drift time of the electrons. The advances of this readout system consist therein that a better position resolution than by a multiwire proportional chamber is reached and the back-drifting ions can be strongly suppressed. Aim of this thesis are studies for a GEM module, which shall be used in a large TPC prototype. Concerning different requirements it is valid to compare different GEMs in order to can meet an optimal choice. In a small prototype present at DESY measurements for the acquisition of GEM-describing parameters were performed. The taking into operation of the test TPC was part of this thesis. Tracks were generated by a radioactive source, by means of which the gas amplification was determined. With the measurement arrangement gas-amplifier foils of different kind were compared in view of their amplification properties and their energy resolution power and systematically studied. Five different GEM performances were studied in the test TPC. These foils differ in their geometrical classification parameters, the fabrication process, or the materials. The GEMs produced at CERN possess in comparison with GEMs of the Japanese firm SciEnergy and a GEM of the US-American firm Tech-Etch the best amplification and resolution properties. Furthermore a new GEM framing

  9. Development of a GEM based detector for the CBM Muon Chamber (MUCH)

    CERN Document Server

    Biswas, S; Abuhoza, A; Frankenfeld, U; Garabatos, C; Hehner, J; Kleipa, V; Morhardt, T; Schmidt, C J; Schmidt, H R; Wiechula, J

    2013-01-01

    The characteristics of triple GEM detectors have been studied systematically by using cosmic ray muons. The minimum ionizing particle (MIP) spectra has been taken for different GEM voltage setting. Efficiency of GEM detector has been measured for cosmic ray. At high rate operation of GEMs the value of the protection resistor influences the gain and the stability. This feature has been investigated varying both the rate and the value of the protection resistor. This measurement has been performed using both X-ray generator and Fe55 source. The ageing and long-term stability of GEM based detectors has been studied employing both X-ray generator and Fe55 source. The ageing study of one GEM module is performed by using a 8 keV Cu X-ray generator to verify the stability and integrity of the GEM detectors over a longer period of time. The accumulated charge on the detector is calculated from the rate of the X-ray and the average gain of the detector. The details of the measurement and results has been described in ...

  10. Application of GEM-based detectors in full-field XRF imaging

    Science.gov (United States)

    Dąbrowski, W.; Fiutowski, T.; Frączek, P.; Koperny, S.; Lankosz, M.; Mendys, A.; Mindur, B.; Świentek, K.; Wiącek, P.; Wróbel, P. M.

    2016-12-01

    X-ray fluorescence spectroscopy (XRF) is a commonly used technique for non-destructive elemental analysis of cultural heritage objects. It can be applied to investigations of provenance of historical objects as well as to studies of art techniques. While the XRF analysis can be easily performed locally using standard available equipment there is a growing interest in imaging of spatial distribution of specific elements. Spatial imaging of elemental distrbutions is usually realised by scanning an object with a narrow focused X-ray excitation beam and measuring characteristic fluorescence radiation using a high energy resolution detector, usually a silicon drift detector. Such a technique, called macro-XRF imaging, is suitable for investigation of flat surfaces but it is time consuming because the spatial resolution is basically determined by the spot size of the beam. Another approach is the full-field XRF, which is based on simultaneous irradiation and imaging of large area of an object. The image of the investigated area is projected by a pinhole camera on a position-sensitive and energy dispersive detector. The infinite depth of field of the pinhole camera allows one, in principle, investigation of non-flat surfaces. One of possible detectors to be employed in full-field XRF imaging is a GEM based detector with 2-dimensional readout. In the paper we report on development of an imaging system equipped with a standard 3-stage GEM detector of 10 × 10 cm2 equipped with readout electronics based on dedicated full-custom ASICs and DAQ system. With a demonstrator system we have obtained 2-D spatial resolution of the order of 100 μm and energy resolution at a level of 20% FWHM for 5.9 keV . Limitations of such a detector due to copper fluorescence radiation excited in the copper-clad drift electrode and GEM foils is discussed and performance of the detector using chromium-clad electrodes is reported.

  11. First proof of topological signature in high pressure xenon gas with electroluminescence amplification

    CERN Document Server

    Ferrario, P.; López-March, N.; Gómez-Cadenas, J.J.; Álvarez, V.; Azevedo, C.D.R.; Borges, F.I.G.; Cárcel, S.; Cebrián, S.; Cervera, A.; Conde, C.A.N.; Dafni, T.; Díaz, J.; Diesburg, M.; Esteve, R.; Fernandes, L.M.P.; Ferreira, A.L.; Freitas, E.D.C.; Gehman, V.M.; Goldschmidt, A.; González-Díaz, D.; Gutiérrez, R.M.; Hauptman, J.; Henriques, C.A.O.; Hernando Morata, J.A.; Irastorza, I.G.; Labarga, L.; Lebrun, P.; Liubarsky, I.; Lorca, D.; Losada, M.; Luzón, G.; Marí, A.; Martín-Albo, J.; Martínez-Lema, G.; Martínez, A.; Miller, T.; Monrabal, F.; Monserrate, M.; Monteiro, C.M.B.; Mora, F.J.; Moutinho, L.M.; Muñoz Vidal, J.; Nebot-Guinot, M.; Novella, P.; Nygren, D.; Para, A.; Pérez, J.; Pérez Aparicio, J.L.; Querol, M.; Renner, J.; Ripoll, L.; Rodríguez, J.; Santos, F.P.; dos Santos, J.M.F.; Serra, L.; Shuman, D.; Simón, A.; Sofka, C.; Sorel, M.; Toledo, J.F.; Torrent, J.; Tsamalaidze, Z.; Veloso, J.F.C.A.; Villar, J.A.; Webb, R.; White, J.T.; Yahlali, N.; Yepes-Ramírez, H.

    2016-01-01

    The NEXT experiment aims to observe the neutrinoless double beta decay of xenon in a high-pressure Xe136 gas TPC using electroluminescence (EL) to amplify the signal from ionization. One of the main advantages of this technology is the possibility to reconstruct the topology of events with energies close to Qbb. This paper presents the first demonstration that the topology provides extra handles to reject background events using data obtained with the NEXT-DEMO prototype. Single electrons resulting from the interactions of Na22 1275 keV gammas and electron-positron pairs produced by conversions of gammas from the Th228 decay chain were used to represent the background and the signal in a double beta decay. These data were used to develop algorithms for the reconstruction of tracks and the identification of the energy deposited at the end-points, providing an extra background rejection factor of 24.3 +- 1.4 (stat.)%, while maintaining an efficiency of 66.7 +- 0.6 (stat.)% for signal events.

  12. First proof of topological signature in high pressure xenon gas with electroluminescence amplification

    CERN Document Server

    Ferrario, P; López-March, N.; Gómez-Cadenas, J.J.; Álvarez, V.; Azevedo, C.D.R.; Borges, F.I.G.; Cárcel, S.; Cebrián, S.; Cervera, A.; Conde, C.A.N.; Dafni, T.; Díaz, J.; Diesburg, M.; Esteve, R.; Fernandes, L.M.P.; Ferreira, A.L.; Freitas, E.D.C.; Gehman, V.M.; Goldschmidt, A.; González-Díaz, D.; Gutiérrez, R.M.; Hauptman, J.; Henriques, C.A.O.; Hernando Morata, J.A.; Irastorza, I.G.; Labarga, L.; Lebrun, P.; Liubarsky, I.; Lorca, D.; Losada, M.; Luzón, G.; Marí, A.; Martín-Albo, J.; Martínez-Lema, G.; Martínez, A.; Miller, T.; Monrabal, F.; Monserrate, M.; Monteiro, C.M.B.; Mora, F.J.; Moutinho, L.M.; Muñoz Vidal, J.; Nebot-Guinot, M.; Novella, P.; Nygren, D.; Para, A.; Pérez, J.; Pérez Aparicio, J.L.; Querol, M.; Renner, J.; Ripoll, L.; Rodríguez, J.; Santos, F.P.; dos Santos, J.M.F.; Serra, L.; Shuman, D.; Simón, A.; Sofka, C.; Sorel, M.; Toledo, J.F.; Torrent, J.; Tsamalaidze, Z.; Veloso, J.F.C.A.; Villar, J.A.; Webb, R.; White, J.T.; Yahlali, N.; Yepes-Ramírez, H.

    2016-01-01

    The NEXT experiment aims to observe the neutrinoless double beta decay of xenon in a high-pressure Xe136 gas TPC using electroluminescence (EL) to amplify the signal from ionization. One of the main advantages of this technology is the possibility to reconstruct the topology of events with energies close to Qbb. This paper presents the first demonstration that the topology provides extra handles to reject background events using data obtained with the NEXT-DEMO prototype. Single electrons resulting from the interactions of Na22 1275 keV gammas and electron-positron pairs produced by conversions of gammas from the Th228 decay chain were used to represent the background and the signal in a double beta decay. These data were used to develop algorithms for the reconstruction of tracks and the identification of the energy deposited at the end-points, providing an extra background rejection factor of 24.3 +- 1.4 (stat.)%, while maintaining an efficiency of 66.7 +- 0.6 (stat.)% for signal events.

  13. Methods and results for calibration and track separation of a GEM based TPC using an UV-laser

    Energy Technology Data Exchange (ETDEWEB)

    Ball, Markus

    2008-12-15

    In the last 30 years high energy physics could write an impressive story of success. Since the introduction of the Standard Model (SM), it has met every experimental test. However the final confirmation has to prove the mechanism of electroweak symmetry breaking, which could not be confirmed yet. The most favored theory, which includes the introduction of a Higgs field, could not be verified experimentally. Furthermore there is clear evidence, that the SM is only a low energy description of nature and its principles, as the SM describes only 4 % of the known matter in the universe. There are two different approaches in accelerator driven high energy physics to clarify the open questions. The Large Hadron Collider (LHC) have a good opportunity to measure some of the missing pieces with its high center of mass energy. The International Linear Collider (ILC) will then measure their parameters with high precision. To guarantee this high precision the detectors have to be able to identify every single particle and determine its properties with high accuracy. These high requirements to the single detectors as well as the interconnectivity between all detectors are summarised by the concept of particle flow (PFLOW). This means that all particles must be separable, which includes in particular the main tracking device. A possible candidate for the central tracking device is a Time Projection Chamber (TPC). In this work a TPC with Gas Electron Multipliers (GEM) as gas amplification system was used. The GEMs replace the conventional wire amplification system of the TPC. In this PhD work a method to determine the drift velocity of a TPC was developed and tested using an ultraviolet laser. To ensure a high accuracy of the method all relevant gas parameters were measured with a slow control system. Furthermore the laser was used to investigate the separation capability of nearby tracks. Therefore an existing TPC prototype, which was developed to operate in a 5 T magnet facility

  14. Development and Test of a GEM-Based TEPC System for In-Phantom Dose Measurements

    Energy Technology Data Exchange (ETDEWEB)

    C-K Chris Wang

    2007-03-13

    The objectives of this project include: (1) to construct a minature tissue equivalent proportional counter (TEPC) using a gas-electron-multiplier (GEM) foil, and (2) to conduct neutron and gamma-ray dose measurements with the detector embedded in a phantom

  15. Conceptual design and development of GEM based detecting system for tomographic tungsten focused transport monitoring

    Science.gov (United States)

    Chernyshova, M.; Czarski, T.; Malinowski, K.; Kowalska-Strzęciwilk, E.; Poźniak, K.; Kasprowicz, G.; Zabołotny, W.; Wojeński, A.; Kolasiński, P.; Mazon, D.; Malard, P.

    2015-10-01

    Implementing tungsten as a plasma facing material in ITER and future fusion reactors will require effective monitoring of not just its level in the plasma but also its distribution. That can be successfully achieved using detectors based on Gas Electron Multiplier (GEM) technology. This work presents the conceptual design of the detecting unit for poloidal tomography to be tested at the WEST project tokamak. The current stage of the development is discussed covering aspects which include detector's spatial dimensions, gas mixtures, window materials and arrangements inside and outside the tokamak ports, details of detector's structure itself and details of the detecting module electronics. It is expected that the detecting unit under development, when implemented, will add to the safe operation of tokamak bringing the creation of sustainable nuclear fusion reactors a step closer. A shorter version of this contribution is due to be published in PoS at: 1st EPS conference on Plasma Diagnostics

  16. Optically read out GEM-based TPC operation and preliminary scintillation studies

    CERN Document Server

    Galgoczi, Gabor

    2016-01-01

    The main goal of this project was to realise the reconstruction of tracks in an optically read out GEM (Gas Electron Multiplier) based Time Projection Chamber (TPC). Secondary goal was to initialise a series of systematic studies on the scintillation of particles in Ar/CF4 (80-20%) mixture. Track reconstruction is needed for primary scintillation studies as only tracks fully contained can be considered. A vetoing and trigerring logic was built for the TPC from NIM modules.

  17. A new design using GEM-based technology for the CMS experiment

    CERN Document Server

    Ressegotti, Martina

    2017-01-01

    The muon system of the Compact Muon Solenoid (CMS) experiment at the LHC is currently not instrumented for pseudorapidity higher than abs(${\\eta}$)${ > 2.4}$. The main challenges to the installation of a detector in that position are the high particle flux to be sustained, a high level of radiation, and the ability to accomodate a multilevel detector into the small available space (less than 30 cm). A new back-to-back configuration of a Gas Electron Multiplier (GEM) detector is presented with the aim of developing a compact, multi-layer GEM detector. It is composed of two independent stacked triple-GEM detectors, positioned with the anodes toward the outside and sharing the same cathode plane, which is located at the center of the chamber, to reduce the total detector's thickness. A first prototype has been produced and tested with an X-Ray source and muon beam. First results on its performance are presented.

  18. Precision meson spectroscopy. Diffractive production at COMPASS and development of a GEM-based TPC for PANDA

    Energy Technology Data Exchange (ETDEWEB)

    Weitzel, Quirin

    2008-09-24

    . Due to its excellent tracking capabilities for charged particles, a time projection chamber (TPC) has been proposed for the central tracker of PANDA. A continuous operation without ion gate is foreseen, which constitutes a novel development in high-rate particle physics experiments. Gas Electron Multiplier (GEM) foils offer an intrinsic ion back-flow suppression combined with high gains, and will therefore be used for gas amplification. A small-size GEM-TPC test chamber has been constructed during this thesis and commissioned using both X-rays and muons from cosmic-ray air-showers. From the latter data, a spatial resolution down to 140 {mu}m has been achieved. The detector has been operated stably for many months with Ar/CO{sub 2} (70/30) and at typical gas amplification factors of (5-10).10{sup 3}. (orig.)

  19. Amplification, Saturation, and Q Thresholds for Runaway Growth of Self-Gravitating Structures in Models of Magnetized Galactic Gas Disks

    CERN Document Server

    Kim, W T; Kim, Woong-Tae; Ostriker, Eve C.

    2001-01-01

    We investigate the susceptibility of gaseous, magnetized galactic disks to formation of self-gravitating condensations using two-dimensional, local models. We focus on two issues: (1) determining the threshold condition for gravitational runaway, taking into account nonlinear effects, and (2) distinguishing the magneto-Jeans instability (MJI) that arises under inner-galaxy rotation curves from the modified swing amplification (MSA) that arises under outer-galaxy rotation curves. For axisymmetric density fluctuations, instability is known to require a Toomre parameter Q<1. For nonaxisymmetric fluctuations, any nonzero shear $q \\equiv -d\\ln \\Omega /d \\ln R$ winds up wavefronts such that in linear theory amplification saturates. Any Q threshold for nonaxisymmetric gravitational runaway must originate from nonlinear effects. We use numerical magnetohydrodynamic simulations to demonstrate the anticipated threshold phenomenon, to analyze the nonlinear processes involved, and to evaluate the critical value $Q_c$ ...

  20. The detection of single electrons using a Microgas gas amplification and a MediPix2 CMOS pixel readout

    NARCIS (Netherlands)

    Forniani, A.; Campbell, M.; Chefdeville, M.A.; Colas, P.; Colijn, A.P.; Graaf, van der H.; Giomataris, Y.; Heijne, E.H.M.; Kluit, P.; Llopart, X.; Schmitz, J.; Timmermans, J.; Visschers, J.L.

    2005-01-01

    By placing a Micromegas gas gain grid on top of a CMOS pixel readout circuit (MediPix2), we developed a device which acts as a pixel-segmented direct anode in gas-filled detectors. With a He/Isobutane 80/20 mixture (capable of achieving gas gain factors up to 20×103) and employing a drift length of

  1. A High Position Resolution X-ray Detector: an Edge on Illuminated Capillary Plate Combined with a Gas Amplification Structure

    CERN Document Server

    Iacobaeus, C; Lund-Jensen, B; Ostling, J; Pavlopoulos, P; Peskov, Vladimir; Tokanai, F

    2006-01-01

    We have developed and successfully tested a prototype of a new type of high position resolution hybrid X-ray detector. It contains a thin wall lead glass capillary plate converter of X-rays combined with a microgap parallel-plate avalanche chamber filled with gas at 1 atm. The operation of these converters was studied in a wide range of X-ray energies (from 6 to 60 keV) at incident angles varying from 0-90 degree. The detection efficiency, depending on the geometry, photon energy, incident angle and the mode of operation, was between 5-30 percent in a single step mode and up to 50 percent in a multi-layered combination. Depending on the capillary geometry, the position resolution achieved was between 0.050-0.250 mm in digital form and was practically independent of the photon energy or gas mixture. The usual lead glass capillary plates operated without noticeable charging up effects at counting rates of 50 Hz/mm2, and hydrogen treated capillaries up to 10E5 Hz/mm2. The developed detector may open new possibil...

  2. First demonstration of VUV-photon detection in liquid xenon with THGEM and GEM-based Liquid Hole Multipliers

    CERN Document Server

    Erdal, E; Rappaport, M; Shchemelinin, S; Vartsky, D; Breskin, A

    2016-01-01

    The bubble-assisted Liquid Hole-Multiplier (LHM) is a recently-introduced detection concept for noble-liquid time projection chambers. In this "local dual-phase" detection element, a gas bubble is supported underneath a perforated electrode (e.g., Thick Gas Electron Multiplier - THGEM, or Gas Electron Multiplier - GEM). Electrons drifting through the holes induce large electroluminescence signals as they pass into the bubble. In this work we report on recent results of THGEM and GEM electrodes coated with cesium iodide and immersed in liquid xenon, allowing - for the first time - the detection of primary VUV scintillation photons in addition to ionization electrons using LHMs.

  3. Slow photon amplification of gas-phase ethanol photo-oxidation in titania inverse opal photonic crystals

    Science.gov (United States)

    Jovic, Vedran; Idriss, Hicham; Waterhouse, Geoffrey I. N.

    2016-11-01

    Here we describe the successful fabrication of six titania inverse opal (TiO2 IO) photocatalysts with fcc[1 1 1] pseudo photonic band gaps (PBGs) tuned to span the UV-vis region. Photocatalysts were fabricated by a colloidal crystal templating and sol-gel approach - a robust and highly applicable bottom-up scheme which allowed for precise control over the geometric and optical properties of the TiO2 IO photocatalysts. Optical properties of the TiO2 IO thin films were investigated in detail by UV-vis transmittance and reflectance measurements. The PBG along the fcc[1 1 1] direction in the TiO2 IOs was dependent on the inter-planar spacing in the [1 1 1] direction, the incident angle of light and the refractive index of the medium filling the macropores in the IOs, in agreement with a modified Bragg's law expression. Calculated photonic band structures for the photocatalysts revealed a PBG along the Γ → L direction at a/λ ∼ 0.74, in agreement with the experimental optical data. By coupling the low frequency edge of the PBG along the [1 1 1] direction with the electronic absorption edge of anatase TiO2, a two-fold enhancement in the rate of gas phase ethanol photo-oxidation in air was achieved. This enhancement appears to be associated with a 'slow photon' effect that acts to both enhance TiO2 absorption and inhibit spontaneous emission (i.e. suppress electron-hole pair recombination).

  4. Study of spatial resolution of coordinate detectors based on Gas Electron Multipliers

    Science.gov (United States)

    Kudryavtsev, V. N.; Maltsev, T. V.; Shekhtman, L. I.

    2017-02-01

    Spatial resolution of GEM-based tracking detectors is determined in the simulation and measured in the experiments. The simulation includes GEANT4 implemented transport of high energy electrons with careful accounting of atomic relaxation processes including emission of fluorescent photons and Auger electrons and custom post-processing with accounting of diffusion, gas amplification fluctuations, distribution of signals on readout electrodes, electronics noise and particular algorithm of final coordinate calculation (center of gravity). The simulation demonstrates that the minimum of spatial resolution of about 10 μm can be achieved with a gas mixture of Ar -CO2 (75-25 %) at a strips pitch from 250 μm to 300 μm. At a larger pitch the resolution quickly degrades reaching 80-100 μm at a pitch of 460-500 μm. Spatial resolution of low-material triple-GEM detectors for the DEUTERON facility at the VEPP-3 storage ring is measured at the extracted beam facility of the VEPP-4 M collider. One-coordinate resolution of the DEUTERON detector is measured with electron beam of 500 MeV, 1 GeV and 3.5 GeV energies. The determined value of spatial resolution varies in the range from approximately 35 μm to 50 μm for orthogonal tracks in the experiments.

  5. Construction of the first full-size GEM-based prototype for the CMS high-$\\eta$ muon system

    CERN Document Server

    Abbaneo, D; Postema, H; Conde Garcia, A; Chatelain, J P; Faber, G; Ropelewski, L; Duarte Pinto, S; Croci, G; Alfonsi, M; Van Stenis, M; Sharma, A; Benussi, L; Bianco, S; Colafranceschi, S; Fabbri, F; Passamonti, L; Piccolo, D; Pierluigi, D; Raffone, G; Russo, A; Saviano, G; Marinov, A; Tytgat, M; Zaganidis, N; Hohlmann, M; Gnanvo, K; Bagliesi, M G; Cecchi, R; Turini, N; Oliveri, E; Magazzù, G; Ban, Y; Teng, H; Cai, J

    2010-01-01

    In view of a possible extension of the forward CMS muon detector system and future LHC luminosity upgrades, Micro-Pattern Gas Detectors (MPGDs) are an appealing technology. They can simultaneously provide precision tracking and fast trigger information, as well as sufficiently fine segmentation to cope with high particle rates in the high-eta region at LHC and its future upgrades. We report on the design and construction of a full-size prototype for the CMS endcap system, the largest Triple-GEM detector built to-date. We present details on the 3D modeling of the detector geometry, the implementation of the readout strips and electronics, and the detector assembly procedure.

  6. On line separation of overlapped signals from multi-time photons for the GEM-based detection system

    Science.gov (United States)

    Czarski, T.; Pozniak, K. T.; Chernyshova, M.; Malinowski, K.; Kasprowicz, G.; Kolasinski, P.; Krawczyk, R.; Wojenski, A.; Zabolotny, W.

    2015-09-01

    The Triple Gas Electron Multiplier (T-GEM) is presented as soft X-ray (SXR) energy and position sensitive detector for high-resolution X-ray diagnostics of magnetic confinement fusion plasmas. Multi-channel measurement system and serial data acquisition for X-ray energy and position recognition is described. Fundamental characteristics are presented for two dimensional detector structure. Typical signals of ADC - Analog to Digital Converter are considered for charge value and position estimation. Coinciding signals for high flux radiation cause the problem for cluster charge identification. The amplifier with shaper determines time characteristics and limits the pulses frequency. Separation of coincided signals was introduced and verified for simulation experiments. On line separation of overlapped signals was implemented applying the FPGA technology with relatively simple firmware procedure. Representative results for reconstruction of coinciding signals are demonstrated.

  7. The Seneca Amplification Construction

    Directory of Open Access Journals (Sweden)

    Wallace Chafe

    2012-01-01

    Full Text Available The polysynthetic morphology of the Northern Iroquoian languages presents a challenge to studies of clause combining. The discussion here focuses on a Seneca construction that may appear within a single clause but may also straddle clause boundaries. It amplifies the information provided by a referent, here called the trigger, that is introduced by the pronominal prefix within a verb or occasionally in some other way. The particle neh signals that further information about that referent will follow. This construction is found at four levels of syntactic complexity. At the first level the trigger and its amplification occur within the same prosodic phrase and the amplification is a noun. At the second level the amplification occurs in a separate prosodic phrase but remains a noun. At the third level the amplification exhibits verb morphology but has been lexicalized with a nominal function. At the fourth level the amplification functions as a full clause and neh serves as a marker of clause combining. Several varieties of amplification are discussed, as are cases in which the speaker judges that no amplification is needed. It is suggested that the typologically similar Caddo language illustrates a situation in which this construction could never arise, simply because Caddo verbs lack the pronominal element that triggers the construction in Seneca.

  8. Amplification of NOON States

    CERN Document Server

    Agarwal, G S; Rai, Amit

    2009-01-01

    We examine the behavior of a Non Gaussian state like NOON state under phase insensitive amplification. We derive analytical result for the density matrix of the NOON state for arbitrary gain of the amplifier. We consider cases of both symmetric and antisymmetric amplification of the two modes of the NOON state. We quantitatively evaluate the loss of entanglement by the amplifier in terms of the logarithmic negativity parameter. We find that NOON states are more robust than their Gaussian counterparts.

  9. Amplification of NOON States

    OpenAIRE

    2009-01-01

    We examine the behavior of a Non Gaussian state like NOON state under phase insensitive amplification. We derive analytical result for the density matrix of the NOON state for arbitrary gain of the amplifier. We consider cases of both symmetric and antisymmetric amplification of the two modes of the NOON state. We quantitatively evaluate the loss of entanglement by the amplifier in terms of the logarithmic negativity parameter. We find that NOON states are more robust than their Gaussian coun...

  10. A new Jeans resolution criterion for (M)HD simulations of self-gravitating gas: Application to magnetic field amplification by gravity-driven turbulence

    CERN Document Server

    Federrath, Christoph; Schleicher, Dominik R G; Banerjee, Robi; Klessen, Ralf S

    2011-01-01

    Cosmic structure formation is characterized by the complex interplay between gravity, turbulence, and magnetic fields. The processes by which gravitational energy is converted into turbulent and magnetic energies, however, remain poorly understood. Here, we show with high-resolution, adaptive-mesh simulations that MHD turbulence is efficiently driven by extracting energy from the gravitational potential during the collapse of a dense gas cloud. Compressible motions generated during the contraction are converted into solenoidal, turbulent motions, leading to a natural energy ratio of E_sol/E_tot of approximately 2/3. We find that the energy injection scale of gravity-driven turbulence is close to the local Jeans scale. If small seeds of the magnetic field are present, they are amplified exponentially fast via the small-scale dynamo process. The magnetic field grows most efficiently on the smallest scales, for which the stretching, twisting, and folding of field lines, and the turbulent vortices are sufficientl...

  11. Gene amplification in carcinogenesis

    Directory of Open Access Journals (Sweden)

    Lucimari Bizari

    2006-01-01

    Full Text Available Gene amplification increases the number of genes in a genome and can give rise to karyotype abnormalities called double minutes (DM and homogeneously staining regions (HSR, both of which have been widely observed in human tumors but are also known to play a major role during embryonic development due to the fact that they are responsible for the programmed increase of gene expression. The etiology of gene amplification during carcinogenesis is not yet completely understood but can be considered a result of genetic instability. Gene amplification leads to an increase in protein expression and provides a selective advantage during cell growth. Oncogenes such as CCND1, c-MET, c-MYC, ERBB2, EGFR and MDM2 are amplified in human tumors and can be associated with increased expression of their respective proteins or not. In general, gene amplification is associated with more aggressive tumors, metastases, resistance to chemotherapy and a decrease in the period during which the patient stays free of the disease. This review discusses the major role of gene amplification in the progression of carcinomas, formation of genetic markers and as possible therapeutic targets for the development of drugs for the treatment of some types of tumors.

  12. Biomaterials in light amplification

    Science.gov (United States)

    Mysliwiec, Jaroslaw; Cyprych, Konrad; Sznitko, Lech; Miniewicz, Andrzej

    2017-03-01

    Biologically produced or inspired materials can serve as optical gain media, i.e. they can exhibit the phenomenon of light amplification. Some of these materials, under suitable dye-doping and optical pumping conditions, show lasing phenomena. The emerging branch of research focused on obtaining lasing action in highly disordered and highly light scattering materials, i.e. research on random lasing, is perfectly suited for biological materials. The use of biomaterials in light amplification has been extensively reported in the literature. In this review we attempt to report on progress in the development of biologically derived systems able to show the phenomena of light amplification and random lasing together with the contribution of our group to this field. The rich world of biopolymers modified with molecular aggregates and nanocrystals, and self-organized at the nanoscale, offers a multitude of possibilities for tailoring luminescent and light scattering properties that are not easily replicated in conventional organic or inorganic materials. Of particular importance and interest are light amplification and lasing, or random lasing studies in biological cells and tissues. In this review we will describe nucleic acids and their complexes employed as gain media due to their favorable optical properties and ease of manipulation. We will report on research conducted on various biomaterials showing structural analogy to nucleic acids such as fluorescent proteins, gelatins in which the first distributed feedback laser was realized, and also amyloids or silks, which, due to their dye-doped fiber-like structure, allow for light amplification. Other materials that were investigated in that respect include polysaccharides, like starch exhibiting favorable photostability in comparison to other biomaterials, and chitosan, which forms photonic crystals or cellulose. Light amplification and random lasing was not only observed in processed biomaterials but also in living

  13. Hardness amplification in nondeterministic logspace

    OpenAIRE

    Gupta, Sushmita

    2007-01-01

    A hard problem is one which cannot be easily computed by efficient algorithms. Hardness amplification is a procedure which takes as input a problem of mild hardness and returns a problem of higher hardness. This is closely related to the task of decoding certain error-correcting codes. We show amplification from mild average case hardness to higher average case hardness for nondeterministic logspace and worst-to-average amplification for nondeterministic linspace. Finally we explore possible ...

  14. Isothermal Amplification of Nucleic Acids.

    Science.gov (United States)

    Zhao, Yongxi; Chen, Feng; Li, Qian; Wang, Lihua; Fan, Chunhai

    2015-11-25

    Isothermal amplification of nucleic acids is a simple process that rapidly and efficiently accumulates nucleic acid sequences at constant temperature. Since the early 1990s, various isothermal amplification techniques have been developed as alternatives to polymerase chain reaction (PCR). These isothermal amplification methods have been used for biosensing targets such as DNA, RNA, cells, proteins, small molecules, and ions. The applications of these techniques for in situ or intracellular bioimaging and sequencing have been amply demonstrated. Amplicons produced by isothermal amplification methods have also been utilized to construct versatile nucleic acid nanomaterials for promising applications in biomedicine, bioimaging, and biosensing. The integration of isothermal amplification into microsystems or portable devices improves nucleic acid-based on-site assays and confers high sensitivity. Single-cell and single-molecule analyses have also been implemented based on integrated microfluidic systems. In this review, we provide a comprehensive overview of the isothermal amplification of nucleic acids encompassing work published in the past two decades. First, different isothermal amplification techniques are classified into three types based on reaction kinetics. Then, we summarize the applications of isothermal amplification in bioanalysis, diagnostics, nanotechnology, materials science, and device integration. Finally, several challenges and perspectives in the field are discussed.

  15. Efficient audio power amplification - challenges

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, Michael A.E.

    2005-07-01

    For more than a decade efficient audio power amplification has evolved and today switch-mode audio power amplification in various forms are the state-of-the-art. The technical steps that lead to this evolution are described and in addition many of the challenges still to be faced and where extensive research and development are needed is covered. (au)

  16. Large Brillouin Amplification in Silicon

    CERN Document Server

    Kittlaus, Eric A; Rakich, Peter T

    2015-01-01

    Strong Brillouin coupling has only recently been realized in silicon using a new class of optomechanical waveguides that yield both optical and phononic confinement. Despite these major advances, appreciable Brillouin amplification has yet to be observed in silicon. Using a new membrane-suspended silicon waveguide we report large Brillouin amplification for the first time, reaching levels greater than 5 dB for modest pump powers, and demonstrate a record low (5 mW) threshold for net amplification. This work represents a crucial advance necessary to realize high-performance Brillouin lasers and amplifiers in silicon.

  17. Next generation Chirped Pulse Amplification

    Energy Technology Data Exchange (ETDEWEB)

    Nees, J.; Biswal, S.; Mourou, G. [Univ. Michigan, Center for Ultrafast Optical Science, Ann Arbor, MI (United States); Nishimura, Akihiko; Takuma, Hiroshi

    1998-03-01

    The limiting factors of Chirped Pulse Amplification (CPA) are discussed and experimental results of CPA in Yb:glass regenerative amplifier are given. Scaling of Yb:glass to the petawatt level is briefly discussed. (author)

  18. Uncertainties in Site Amplification Estimation

    Science.gov (United States)

    Cramer, C. H.; Bonilla, F.; Hartzell, S.

    2004-12-01

    Typically geophysical profiles (layer thickness, velocity, density, Q) and dynamic soil properties (modulus and damping versus strain curves) are used with appropriate input ground motions in a soil response computer code to estimate site amplification. Uncertainties in observations can be used to generate a distribution of possible site amplifications. The biggest sources of uncertainty in site amplifications estimates are the uncertainties in (1) input ground motions, (2) shear-wave velocities (Vs), (3) dynamic soil properties, (4) soil response code used, and (5) dynamic pore pressure effects. A study of site amplification was conducted for the 1 km thick Mississippi embayment sediments beneath Memphis, Tennessee (see USGS OFR 04-1294 on the web). In this study, the first three sources of uncertainty resulted in a combined coefficient of variation of 10 to 60 percent. The choice of soil response computer program can lead to uncertainties in median estimates of +/- 50 percent. Dynamic pore pressure effects due to the passing of seismic waves in saturated soft sediments are normally not considered in site-amplification studies and can contribute further large uncertainties in site amplification estimates. The effects may range from dilatancy and high-frequency amplification (such as observed at some sites during the 1993 Kushiro-Oki, Japan and 2001 Nisqually, Washington earthquakes) or general soil failure and deamplification of ground motions (such as observed at Treasure Island during the 1989 Loma Prieta, California earthquake). Examples of two case studies using geotechnical data for downhole arrays in Kushiro, Japan and the Wildlife Refuge, California using one dynamic code, NOAH, will be presented as examples of modeling uncertainties associated with these effects. Additionally, an example of inversion for estimates of in-situ dilatancy-related geotechnical modeling parameters will be presented for the Kushiro, Japan site.

  19. Isothermal Amplification of Insect DNA

    Science.gov (United States)

    The loop-mediated isothermal amplification of DNA (LAMP) method can amplify a target DNA sequence at a constant temperature in about one hour. LAMP has broad application in agriculture and medicine because of the need for rapid and inexpensive diagnoses. LAMP eliminates the need for temperature cycl...

  20. The efficiency of magnetic field amplification at shocks by turbulence

    Science.gov (United States)

    Ji (), Suoqing; Oh, S. Peng; Ruszkowski, M.; Markevitch, M.

    2016-12-01

    Turbulent dynamo field amplification has often been invoked to explain the strong field strengths in thin rims in supernova shocks ( ˜ 100 μG) and in radio relics in galaxy clusters ( ˜ μG). We present high-resolution magnetohydrodynamic simulations of the interaction between pre-shock turbulence, clumping and shocks, to quantify the conditions under which turbulent dynamo amplification can be significant. We demonstrate numerically converged field amplification which scales with Alfvén Mach number, B/B_0 ∝ M_A, up to M_A ˜ 150. This implies that the post-shock field strength is relatively independent of the seed field. Amplification is dominated by compression at low M_A, and stretching (turbulent amplification) at high M_A. For high M_A, the B-field grows exponentially and saturates at equipartition with turbulence, while the vorticity jumps sharply at the shock and subsequently decays; the resulting field is orientated predominately along the shock normal (an effect only apparent in 3D and not 2D). This agrees with the radial field bias seen in supernova remnants. By contrast, for low M_A, field amplification is mostly compressional, relatively modest, and results in a predominantly perpendicular field. The latter is consistent with the polarization seen in radio relics. Our results are relatively robust to the assumed level of gas clumping. Our results imply that the turbulent dynamo may be important for supernovae, but is only consistent with the field strength, and not geometry, for cluster radio relics. For the latter, this implies strong pre-existing B-fields in the ambient cluster outskirts.

  1. Miniaturized isothermal nucleic acid amplification, a review.

    Science.gov (United States)

    Asiello, Peter J; Baeumner, Antje J

    2011-04-21

    Micro-Total Analysis Systems (µTAS) for use in on-site rapid detection of DNA or RNA are increasingly being developed. Here, amplification of the target sequence is key to increasing sensitivity, enabling single-cell and few-copy nucleic acid detection. The several advantages to miniaturizing amplification reactions and coupling them with sample preparation and detection on the same chip are well known and include fewer manual steps, preventing contamination, and significantly reducing the volume of expensive reagents. To-date, the majority of miniaturized systems for nucleic acid analysis have used the polymerase chain reaction (PCR) for amplification and those systems are covered in previous reviews. This review provides a thorough overview of miniaturized analysis systems using alternatives to PCR, specifically isothermal amplification reactions. With no need for thermal cycling, isothermal microsystems can be designed to be simple and low-energy consuming and therefore may outperform PCR in portable, battery-operated detection systems in the future. The main isothermal methods as miniaturized systems reviewed here include nucleic acid sequence-based amplification (NASBA), loop-mediated isothermal amplification (LAMP), helicase-dependent amplification (HDA), rolling circle amplification (RCA), and strand displacement amplification (SDA). Also, important design criteria for the miniaturized devices are discussed. Finally, the potential of miniaturization of some new isothermal methods such as the exponential amplification reaction (EXPAR), isothermal and chimeric primer-initiated amplification of nucleic acids (ICANs), signal-mediated amplification of RNA technology (SMART) and others is presented.

  2. Spheromak Impedance and Current Amplification

    Energy Technology Data Exchange (ETDEWEB)

    Fowler, T K; Hua, D D; Stallard, B W

    2002-01-31

    It is shown that high current amplification can be achieved only by injecting helicity on the timescale for reconnection, {tau}{sub REC}, which determines the effective impedance of the spheromak. An approximate equation for current amplification is: dI{sub TOR}{sup 2}/dt {approx} I{sup 2}/{tau}{sub REC} - I{sub TOR}{sup 2}/{tau}{sub closed} where I is the gun current, I{sub TOR} is the spheromak toroidal current and {tau}{sub CLOSED} is the ohmic decay time of the spheromak. Achieving high current amplification, I{sub TOR} >> I, requires {tau}{sub REC} <<{tau}{sub CLOSED}. For resistive reconnection, this requires reconnection in a cold zone feeding helicity into a hot zone. Here we propose an impedance model based on these ideas in a form that can be implemented in the Corsica-based helicity transport code. The most important feature of the model is the possibility that {tau}{sub REC} actually increases as the spheromak temperature increases, perhaps accounting for the ''voltage sag'' observed in some experiments, and a tendency toward a constant ratio of field to current, B {proportional_to} I, or I{sub TOR} {approx} I. Program implications are discussed.

  3. Gas electron multiplier based on laser-perforated CVD diamond film: First tests

    CERN Document Server

    Franchino, S; Bolshakov, A; Ashkinazi, E; Kalkan, Y; Popovich, A; Komlenok, M; Sosnovtsev, V; Ralchenko, V

    2016-01-01

    Gas electron multiplier (GEM) is widely used in modern gas detectors of ionizing radiation in experiments on high-energy physics at accelerators and in other fields of science. Typically the GEM devices are based on a dielectric foil with holes and electrodes on both sides. GEMs made by radiation-hard dielectrics or wide band-gap semiconductors are desirable for some applications. The results of the first tests of the gas electron multiplier made of radiation-hard materials, such as polycrystalline CVD diamond with a thickness of 100 microns is described. Here we report on fabrication of GEM based on free-standing polycrystalline CVD diamond film and its first test.

  4. Antiproton beam profile measurements using Gas Electron Multipliers

    CERN Document Server

    Pinto, Serge Duarte; Spanggaard, Jens; Tranquille, Gerard

    2011-01-01

    The new beam profile measurement for the Antiproton Decelerator (AD) at CERN is based on a single Gas Electron Multiplier (GEM) with a 2D readout structure. This detector is very light, ~0.4% X_0, as required by the low energy of the antiprotons, 5.3 MeV. This overcomes the problems previously encountered with multi-wire proportional chambers (MWPC) for the same purpose, where beam interactions with the detector severely affect the obtained profiles. A prototype was installed and successfully tested in late 2010, with another five detectors now installed in the ASACUSA and AEgIS beam lines. We will provide a detailed description of the detector and discuss the results obtained. The success of these detectors in the AD makes GEM-based detectors likely candidates for upgrade of the beam profile monitors in all experimental areas at CERN. The various types of MWPC currently in use are aging and becoming increasingly difficult to maintain.

  5. Dynamics and Control of DNA Sequence Amplification

    CERN Document Server

    Marimuthu, Karthikeyan

    2014-01-01

    DNA amplification is the process of replication of a specified DNA sequence \\emph{in vitro} through time-dependent manipulation of its external environment. A theoretical framework for determination of the optimal dynamic operating conditions of DNA amplification reactions, for any specified amplification objective, is presented based on first-principles biophysical modeling and control theory. Amplification of DNA is formulated as a problem in control theory with optimal solutions that can differ considerably from strategies typically used in practice. Using the Polymerase Chain Reaction (PCR) as an example, sequence-dependent biophysical models for DNA amplification are cast as control systems, wherein the dynamics of the reaction are controlled by a manipulated input variable. Using these control systems, we demonstrate that there exists an optimal temperature cycling strategy for geometric amplification of any DNA sequence and formulate optimal control problems that can be used to derive the optimal tempe...

  6. Dynamics and control of DNA sequence amplification

    Energy Technology Data Exchange (ETDEWEB)

    Marimuthu, Karthikeyan [Department of Chemical Engineering and Center for Advanced Process Decision-Making, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Chakrabarti, Raj, E-mail: raj@pmc-group.com, E-mail: rajc@andrew.cmu.edu [Department of Chemical Engineering and Center for Advanced Process Decision-Making, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Division of Fundamental Research, PMC Advanced Technology, Mount Laurel, New Jersey 08054 (United States)

    2014-10-28

    DNA amplification is the process of replication of a specified DNA sequence in vitro through time-dependent manipulation of its external environment. A theoretical framework for determination of the optimal dynamic operating conditions of DNA amplification reactions, for any specified amplification objective, is presented based on first-principles biophysical modeling and control theory. Amplification of DNA is formulated as a problem in control theory with optimal solutions that can differ considerably from strategies typically used in practice. Using the Polymerase Chain Reaction as an example, sequence-dependent biophysical models for DNA amplification are cast as control systems, wherein the dynamics of the reaction are controlled by a manipulated input variable. Using these control systems, we demonstrate that there exists an optimal temperature cycling strategy for geometric amplification of any DNA sequence and formulate optimal control problems that can be used to derive the optimal temperature profile. Strategies for the optimal synthesis of the DNA amplification control trajectory are proposed. Analogous methods can be used to formulate control problems for more advanced amplification objectives corresponding to the design of new types of DNA amplification reactions.

  7. Multiscale image contrast amplification (MUSICA)

    Science.gov (United States)

    Vuylsteke, Pieter; Schoeters, Emile P.

    1994-05-01

    This article presents a novel approach to the problem of detail contrast enhancement, based on multiresolution representation of the original image. The image is decomposed into a weighted sum of smooth, localized, 2D basis functions at multiple scales. Each transform coefficient represents the amount of local detail at some specific scale and at a specific position in the image. Detail contrast is enhanced by non-linear amplification of the transform coefficients. An inverse transform is then applied to the modified coefficients. This yields a uniformly contrast- enhanced image without artefacts. The MUSICA-algorithm is being applied routinely to computed radiography images of chest, skull, spine, shoulder, pelvis, extremities, and abdomen examinations, with excellent acceptance. It is useful for a wide range of applications in the medical, graphical, and industrial area.

  8. Risk Perception and Social Amplification

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R.E. [Environment Agency (United Kingdom)

    2001-07-01

    This paper seeks to consider social amplification as it applies to risk perception. Perceptions of the magnitude of a risk are conditioned by issues such as the degree of uncertainty in probability and consequences, the nature of the consequences and the relative weightings placed on probability and consequences. Risk perceptions are also influenced by factors such as confidence in the operator of an industrial process, trust in the regulator and the perceived fairness of regulatory decision-making. Different people may hold different views about these issues and there may also be difficulties in communication. The paper identifies and discusses self-reinforcing mechanisms, which will be labelled 'lock-in' here. They appear to apply in many situations where social amplification is observed. Historically, the term 'lock-in' has been applied mainly in the technological context but, in this paper, four types of lock-in are identified, namely scientific/technological, economic, social and institutional lock-in. One type of lock-in tends to lead to the next and all are buttressed by people's general acceptance of the familiar, fear of the unknown and resistance to change. The regulator seeks to make decisions which achieve the common good rather than supporting or perpetuating any set of vested interests. In this regard the locked-in positions of stakeholders, whether organisations, interest groups, or individual members of the public, are obstacles and challenges. Existing methods of consultation are unsatisfactory in terms of achieving a proper and productive level of dialogue with stakeholders.

  9. Amplification of cellular oncogenes in solid tumors

    Directory of Open Access Journals (Sweden)

    Ozkan Bagci

    2015-01-01

    Full Text Available The term gene amplification refers to an increase in copy number of a gene. Upregulation of gene expression through amplification is a general mechanism to increase gene dosage. Oncogene amplifications have been shown in solid human cancers and they are often associated with progression of cancer. Defining oncogene amplification is useful since it is used as a prognostic marker in clinical oncology nowadays, especially v-erb-b2 avian erythroblastic leukemia viral oncogene homolog 2 (HER2 targeted agents are used in breast cancer patients with high level of HER2 overexpression as a therapeutic approach. However, patients without HER2 overexpression do not appear to benefit from these agents. We concluded that determination of oncogene amplification in solid tumors is an important factor in treatment of human cancers with many unknowns. We have referred to PubMed and some databases to prepare this article.

  10. Pulse Compression And Raman Amplification In Optical Fibres

    Science.gov (United States)

    Byron, Kevin C.

    1988-06-01

    Experimental and theoretical investigations on Raman amplification in fibres have been carried out and simultaneous amplification and pulse compression observed. With a fibre design optimised for amplification high gain may be obtained at practical pump power levels.

  11. Linking Arctic amplification and local feedbacks

    Science.gov (United States)

    Balcerak, Ernie

    2011-11-01

    Climate simulations show that as the Earth warms, the Arctic warms more than the average global warming. However, models differ on how much more the Arctic warms, and although scientists have proposed a variety of mechanisms to explain the Arctic warming amplification, there is no consensus on the main reasons for it. To shed light on this issue, Hwang et al. investigated the relationship between Arctic amplification and poleward energy transport and local Arctic feedbacks, such as changes in cloud cover or ice loss, across a group of models. The researchers noted that differences in atmospheric energy transport did not explain the ranges of polar amplification; rather, models with more amplification showed less energy transport into high latitudes. The authors found that decreasing energy transport is due to a coupled relationship between Arctic amplification and energy transport: Arctic amplification reduces the equator-to-pole temperature gradient, which strongly decreases energy transport. They suggest that this coupled relationship should be taken into account in studies of Arctic amplification. (Geophysical Research Letters, doi:10.1029/2011GL048546, 2011)

  12. Diagnostic Devices for Isothermal Nucleic Acid Amplification

    Directory of Open Access Journals (Sweden)

    Chia-Chen Chang

    2012-06-01

    Full Text Available Since the development of the polymerase chain reaction (PCR technique, genomic information has been retrievable from lesser amounts of DNA than previously possible. PCR-based amplifications require high-precision instruments to perform temperature cycling reactions; further, they are cumbersome for routine clinical use. However, the use of isothermal approaches can eliminate many complications associated with thermocycling. The application of diagnostic devices for isothermal DNA amplification has recently been studied extensively. In this paper, we describe the basic concepts of several isothermal amplification approaches and review recent progress in diagnostic device development.

  13. Advanced backward Raman amplification seeding

    Science.gov (United States)

    Malkin, Vladimir; Fisch, Nathaniel

    2010-11-01

    Next generations of ultrapowerful laser pulses, reaching exawatt and zetawatt powers within reasonably compact facilities, might be based on the backward Raman amplification (BRA) in plasmas. Amplified pulse intensities hundreds times higher than the pump intensity are already observed experimentally. More advanced BRA stages should produce even higher intensities. The largest nonfocused intensity, limited primarily by instabilities associated with the relativistic electron nonlinearity of the amplified laser pulse, is, roughly speaking, 0.1 of the fully relativistic value. It corresponds to the amplified pulse final (and shortest) duration be about the electron plasma wave period. The needed seed pulse should be at least that short then to stay ahead of the amplified pulse, rather than be shadowed by it (which would much reduce the seeding efficiency). However, at earlier BRA stages, when the amplified pulse is longer, the optimal duration of the seed pulse is also longer. This work proposes the use of self-contracting seed pulses for further optimizing the advanced BRA.

  14. Quantum Amplitude Amplification and Estimation

    CERN Document Server

    Brassard, G; Mosca, M; Tapp, A; Brassard, Gilles; Hoyer, Peter; Mosca, Michele; Tapp, Alain

    2000-01-01

    Consider a Boolean function $\\chi: X \\to \\{0,1\\}$ that partitions set $X$ between its good and bad elements, where $x$ is good if $\\chi(x)=1$ and bad otherwise. Consider also a quantum algorithm $\\mathcal A$ such that $A \\ket{0} = \\sum_{x\\in X} \\alpha_x \\ket{x}$ is a quantum superposition of the elements of $X$, and let $a$ denote the probability that a good element is produced if $A \\ket{0}$ is measured. If we repeat the process of running $A$, measuring the output, and using $\\chi$ to check the validity of the result, we shall expect to repeat $1/a$ times on the average before a solution is found. *Amplitude amplification* is a process that allows to find a good $x$ after an expected number of applications of $A$ and its inverse which is proportional to $1/\\sqrt{a}$, assuming algorithm $A$ makes no measurements. This is a generalization of Grover's searching algorithm in which $A$ was restricted to producing an equal superposition of all members of $X$ and we had a promise that a single $x$ existed such tha...

  15. Can Anomalous Amplification be Attained Without Postselection?

    CERN Document Server

    Martínez-Rincón, Julián; Viza, Gerardo I; Howell, John C

    2015-01-01

    We present a parameter estimation technique based on performing joint measurements of a weak interaction away from the weak-value-amplification approximation. Two detectors are used to collect full statistics of the correlations between two weakly entangled degrees of freedom. Without the need of postselection, the protocol resembles the anomalous amplification of an imaginary-weak-value-like response. The amplification is induced in the difference signal of both detectors allowing robustness to different sources of technical noise, and offering in addition the advantages of balanced signals for precision metrology. All of the Fisher information about the parameter of interest is collected, and a phase controls the amplification response. We experimentally demonstrate the proposed technique by measuring polarization rotations in a linearly polarized laser pulse. The effective sensitivity and precision of a split detector is increased when compared to a conventional continuous-wave balanced detection technique...

  16. Rolling circle amplification of metazoan mitochondrialgenomes

    Energy Technology Data Exchange (ETDEWEB)

    Simison, W. Brian; Lindberg, D.R.; Boore, J.L.

    2005-07-31

    Here we report the successful use of rolling circle amplification (RCA) for the amplification of complete metazoan mt genomes to make a product that is amenable to high-throughput genome sequencing techniques. The benefits of RCA over PCR are many and with further development and refinement of RCA, the sequencing of organellar genomics will require far less time and effort than current long PCR approaches.

  17. Optical Sound Generation and Amplification

    Science.gov (United States)

    1983-01-15

    For this purpose we write ^s tRT VCp where u is the angular frequency, M is molecular weight, R is the gas con- stant, T is absolute temperature...compared to the relaxation time. In the case of polyatomic gases with molecular dipole moments and correspondingly high optical absorption coefficients, it...Andrea Prosperetti, Istituto di Fisica , Universita di Mllano, Italy. Measurements are pret.ented in this paper of the pulsation amplitude of an

  18. Advances in Chemical Amplification Resist Systems

    Science.gov (United States)

    Ito, Hiroshi

    1992-12-01

    The chemical amplification concept proposed in 1982 to boost resist sensitivities is now well accepted by the lithography community, which stems not only from high sensitivities that chemical amplification resist systems can offer but also from additional benefits of high contrasts and unexpectedly high resolution capabilities. The design flexibility and versatility that the use of acid as a catalytic species offers are another attractive feature of chemical amplification, giving rise to a birth of an entire family of advanced resist systems. Manufacture and prototype fabrication of DRAM’s by deep UV lithography have been accomplished with use of chemical amplification resists. However, some process problems uniquely associated with chemical amplification resists have surfaced recently, which include their latent image instability due to their sensitivity toward minute amounts of air-borne contaminants. This paper reviews recent advances made in our laboratory in the field of chemical amplification resist systems and discusses 1) influence of residual casting solvent on absorption of NMP by polymer films, 2) effects of polymer end groups on resist sensitivity, and 3) new imaging mechanisms based on acid-catalyzed dehydration.

  19. Heat induces gene amplification in cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Bin, E-mail: yanbin@mercyhealth.com [Department of Radiation Oncology, University of Mississippi Medical Center, Jackson, MS 39213 (United States); Mercy Cancer Center, Mercy Medical Center-North Iowa, Mason City, IA 50401 (United States); Ouyang, Ruoyun [Department of Respiratory Medicine, The Second Xiangya Hospital, Xinagya School of Medicine, Central South University, Changsha 410011 (China); Huang, Chenghui [Department of Radiation Oncology, University of Mississippi Medical Center, Jackson, MS 39213 (United States); Department of Oncology, The Third Xiangya Hospital, Xinagya School of Medicine, Central South University, Changsha 410013 (China); Liu, Franklin [Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710 (United States); Neill, Daniel [Department of Radiation Oncology, University of Mississippi Medical Center, Jackson, MS 39213 (United States); Li, Chuanyuan [Dermatology, Duke University Medical Center, Durham, NC 27710 (United States); Dewhirst, Mark [Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710 (United States)

    2012-10-26

    Highlights: Black-Right-Pointing-Pointer This study discovered that heat exposure (hyperthermia) results in gene amplification in cancer cells. Black-Right-Pointing-Pointer Hyperthermia induces DNA double strand breaks. Black-Right-Pointing-Pointer DNA double strand breaks are considered to be required for the initiation of gene amplification. Black-Right-Pointing-Pointer The underlying mechanism of heat-induced gene amplification is generation of DNA double strand breaks. -- Abstract: Background: Hyperthermia plays an important role in cancer therapy. However, as with radiation, it can cause DNA damage and therefore genetic instability. We studied whether hyperthermia can induce gene amplification in cancer cells and explored potential underlying molecular mechanisms. Materials and methods: (1) Hyperthermia: HCT116 colon cancer cells received water-submerged heating treatment at 42 or 44 Degree-Sign C for 30 min; (2) gene amplification assay using N-(phosphoacetyl)-L-aspartate (PALA) selection of cabamyl-P-synthetase, aspartate transcarbarmylase, dihydro-orotase (cad) gene amplified cells; (3) southern blotting for confirmation of increased cad gene copies in PALA-resistant cells; (4) {gamma}H2AX immunostaining to detect {gamma}H2AX foci as an indication for DNA double strand breaks. Results: (1) Heat exposure at 42 or 44 Degree-Sign C for 30 min induces gene amplification. The frequency of cad gene amplification increased by 2.8 and 6.5 folds respectively; (2) heat exposure at both 42 and 44 Degree-Sign C for 30 min induces DNA double strand breaks in HCT116 cells as shown by {gamma}H2AX immunostaining. Conclusion: This study shows that heat exposure can induce gene amplification in cancer cells, likely through the generation of DNA double strand breaks, which are believed to be required for the initiation of gene amplification. This process may be promoted by heat when cellular proteins that are responsible for checkpoints, DNA replication, DNA repair and

  20. One New Method of Nucleic Acid Amplification-Loop-mediated Isothermal Amplification of DNA

    Institute of Scientific and Technical Information of China (English)

    Xue-en FANG; Jian LI; Qin CHEN

    2008-01-01

    Loop-mediated isothermal amplification (LAMP) is a novel nucleic acid amplification method, which amplifies DNA with high specificity, sensitivity, rapidity and efficiency under isothermal conditions using a set of four specially designed primers and a Bst DNA polymerase with strand displacement activity. The basic principle, characteristics, development of LAMP and its applications are summarized in this article.

  1. Resonant- and avalanche-ionization amplification of laser-induced plasma in air

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yue; Zhang, Zhili, E-mail: zzhang24@utk.edu [Department of Mechanical, Aerospace and Biomedical Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States); Jiang, Naibo; Roy, Sukesh [Spectral Energies, LLC, 5100 Springfield St., Suite 301, Dayton, Ohio 45431 (United States); Gord, James R. [Air Force Research Laboratory, Aerospace Systems Directorate, Wright-Patterson Air Force Base, Ohio 45433 (United States)

    2014-10-14

    Amplification of laser-induced plasma in air is demonstrated utilizing resonant laser ionization and avalanche ionization. Molecular oxygen in air is ionized by a low-energy laser pulse employing (2 + 1) resonance-enhanced multi-photon ionization (REMPI) to generate seed electrons. Subsequent avalanche ionization of molecular oxygen and nitrogen significantly amplifies the laser-induced plasma. In this plasma-amplification effect, three-body attachments to molecular oxygen dominate the electron-generation and -loss processes, while either nitrogen or argon acts as the third body with low electron affinity. Contour maps of the electron density within the plasma obtained in O₂/N₂ and O₂/Ar gas mixtures are provided to show relative degrees of plasma amplification with respect to gas pressure and to verify that the seed electrons generated by O₂ 2 + 1 REMPI are selectively amplified by avalanche ionization of molecular nitrogen in a relatively low-pressure condition (≤100 Torr). Such plasma amplification occurring in air could be useful in aerospace applications at high altitude.

  2. Time varying arctic climate change amplification

    Energy Technology Data Exchange (ETDEWEB)

    Chylek, Petr [Los Alamos National Laboratory; Dubey, Manvendra K [Los Alamos National Laboratory; Lesins, Glen [DALLHOUSIE U; Wang, Muyin [NOAA/JISAO

    2009-01-01

    During the past 130 years the global mean surface air temperature has risen by about 0.75 K. Due to feedbacks -- including the snow/ice albedo feedback -- the warming in the Arctic is expected to proceed at a faster rate than the global average. Climate model simulations suggest that this Arctic amplification produces warming that is two to three times larger than the global mean. Understanding the Arctic amplification is essential for projections of future Arctic climate including sea ice extent and melting of the Greenland ice sheet. We use the temperature records from the Arctic stations to show that (a) the Arctic amplification is larger at latitudes above 700 N compared to those within 64-70oN belt, and that, surprisingly; (b) the ratio of the Arctic to global rate of temperature change is not constant but varies on the decadal timescale. This time dependence will affect future projections of climate changes in the Arctic.

  3. Amplification, Redundancy, and Quantum Chernoff Information

    Science.gov (United States)

    Zwolak, Michael; Riedel, C. Jess; Zurek, Wojciech H.

    2014-04-01

    Amplification was regarded, since the early days of quantum theory, as a mysterious ingredient that endows quantum microstates with macroscopic consequences, key to the "collapse of the wave packet," and a way to avoid embarrassing problems exemplified by Schrödinger's cat. Such a bridge between the quantum microworld and the classical world of our experience was postulated ad hoc in the Copenhagen interpretation. Quantum Darwinism views amplification as replication, in many copies, of the information about quantum states. We show that such amplification is a natural consequence of a broad class of models of decoherence, including the photon environment we use to obtain most of our information. This leads to objective reality via the presence of robust and widely accessible records of selected quantum states. The resulting redundancy (the number of copies deposited in the environment) follows from the quantum Chernoff information that quantifies the information transmitted by a typical elementary subsystem of the environment.

  4. On Arbitrary Phases in Quantum Amplitude Amplification

    CERN Document Server

    Hoyer, P

    2000-01-01

    We consider the use of arbitrary phases in quantum amplitude amplification which is a generalization of quantum searching. We prove that the phase condition in amplitude amplification is given by $\\tan(\\phi/2)=\\tan(\\phi/2)(1-2a)$, where $\\phi$ and $\\phi$ are the phases used and where $a$ is the success probability of the given algorithm. Thus the choice of phases depends nontrivially and nonlinearly on the success probability. Utilizing this condition, we give methods for constructing quantum algorithms that succeed with certainty and for implementing arbitrary rotations. We also conclude that phase errors of order up to $\\frac{1}{\\sqrt{a}}$ can be tolerated in amplitude amplification.

  5. Development of lactococcal GEM-based pneumococcal vaccines.

    NARCIS (Netherlands)

    Audouy, S.A.; Selm, S. van; Roosmalen, M.L. van; Post, E.; Kanninga, R.; Neef, J.; Estevao, S.; Nieuwenhuis, E.E.; Adrian, P.V.; Leenhouts, K.; Hermans, P.W.M.

    2007-01-01

    We report the development of a novel protein-based nasal vaccine against Streptococcus pneumoniae, in which three pneumococcal proteins were displayed on the surface of a non-recombinant, killed Lactococcus lactis-derived delivery system, called Gram-positive Enhancer Matrix (GEM). The GEM particles

  6. Development of lactococcal GEM-based pneumococcal vaccines

    NARCIS (Netherlands)

    Audouy, Sandrine A. L.; van Selm, Saskia; van Roosmalen, Maarten L.; Post, Eduard; Kanninga, Rolf; Neef, Jolanda; Estevao, Silvia; Nieuwenhuis, Edward E. S.; Adrian, Peter V.; Leenhouts, Kees; Hermans, Peter W. M.

    2007-01-01

    We report the development of a novel protein-based nasal vaccine against Streptococcus pneumoniae, in which three pneumococcal proteins were displayed on the surface of a non-recombinant, killed Lactococcus lactis-derived delivery system, called Gram-positive Enhancer Matrix (GEM). The GEM particles

  7. Detection of single photons with THickGEM-based counters

    Energy Technology Data Exchange (ETDEWEB)

    Alexeev, M. [INFN, Sezione di Torino and University of East Piemonte, Alessandria (Italy); Barbosa, F. [I3N - Physics Department, University of Aveiro (Portugal); Birsa, R. [INFN, Sezione di Trieste, Trieste (Italy); Bradamante, F.; Bressan, A. [INFN, Sezione di Trieste and University of Trieste, Trieste (Italy); Chiosso, M. [INFN, Sezione di Torino and University of Torino, Torino (Italy); Ciliberti, P. [INFN, Sezione di Trieste and University of Trieste, Trieste (Italy); Dalla Torre, S. [INFN, Sezione di Trieste, Trieste (Italy); Denisov, O. [INFN, Sezione di Torino, Torino (Italy); Duic, V. [INFN, Sezione di Trieste and University of Trieste, Trieste (Italy); Ferrero, A. [INFN, Sezione di Torino and University of Torino, Torino (Italy); Finger, M.; Finger, M. [Charles University, Praga (Czech Republic); JINR, Dubna (Russian Federation); Fischer, H. [Universitaet Freiburg, Physikalisches Institut, Freiburg (Germany); Giorgi, M. [INFN, Sezione di Trieste and University of Trieste, Trieste (Italy); Gobbo, B.; Gregori, M. [INFN, Sezione di Trieste, Trieste (Italy); Heinsius, F.H.; Herrmann, F.; Koenigsmann, K. [Universitaet Freiburg, Physikalisches Institut, Freiburg (Germany); and others

    2012-12-11

    Cherenkov imaging counters requiring large photosensitive areas, the capability to stand high rates and to operate in magnetic field environments could benefit from the use of photon detectors based on THick Gaseous Electron Multiplier (THGEM) coupled to a solid state CsI photo-cathode. A systematic study of the THGEM detector response as a function of its geometrical parameters and electrodes' applied voltage has been performed. Dedicated electrostatic calculations to optimize the detector design have been accomplished. Data obtained from small photon detector prototypes operating in single photon detection mode are presented and discussed. In particular the key aspect of photo-electron extraction from the photo-cathode surface is investigated via the timing spectrum response of the detector for different electric field conditions at the photo-cathode: a comparison of the measured time distributions and the simulation results is illustrated.

  8. Continuous phase amplification with a Sagnac interferometer

    CERN Document Server

    Starling, David J; Williams, Nathan S; Jordan, Andrew N; Howell, John C

    2009-01-01

    We describe a weak value inspired phase amplification technique in a Sagnac interferometer. We monitor the relative phase between two paths of a slightly misaligned interferometer by measuring the average position of a split-Gaussian mode in the dark port. Although we monitor only the dark port, we show that the signal varies linearly with phase and that we can obtain similar sensitivity to balanced homodyne detection. We derive the source of the amplification both with classical wave optics and as an inverse weak value.

  9. Effective Privacy Amplification for Secure Classical Communications

    CERN Document Server

    Horvath, Tamas; Scheuer, Jacob

    2011-01-01

    We study the effectiveness of privacy amplification for classical key-distribution schemes. We find that, unlike quantum key distribution schemes, the high fidelity of the raw key in classical systems allow the users to always sift a secure shorter key, given that they have an upper bound of eavesdropper probability to correctly guess the exchanged key-bits. We establish the number of privacy amplification iterations needed to achieve information leak of 10^-8 in several classical systems and highlight the inherent tradeoff between the number of iterations and the security of the raw key.

  10. Parametric Amplification For Detecting Weak Optical Signals

    Science.gov (United States)

    Hemmati, Hamid; Chen, Chien; Chakravarthi, Prakash

    1996-01-01

    Optical-communication receivers of proposed type implement high-sensitivity scheme of optical parametric amplification followed by direct detection for reception of extremely weak signals. Incorporates both optical parametric amplification and direct detection into optimized design enhancing effective signal-to-noise ratios during reception in photon-starved (photon-counting) regime. Eliminates need for complexity of heterodyne detection scheme and partly overcomes limitations imposed on older direct-detection schemes by noise generated in receivers and by limits on quantum efficiencies of photodetectors.

  11. A dual amplification fluorescent strategy for sensitive detection of DNA methyltransferase activity based on strand displacement amplification and DNAzyme amplification.

    Science.gov (United States)

    Cui, Wanling; Wang, Lei; Jiang, Wei

    2016-03-15

    DNA methyltransferase (MTase) plays a critical role in many biological processes and has been regarded as a predictive cancer biomarker and a therapeutic target in cancer treatment. Sensitive detection of DNA MTase activity is essential for early cancer diagnosis and therapeutics. Here, we developed a dual amplification fluorescent strategy for sensitive detection of DNA MTase activity based on strand displacement amplification (SDA) and DNAzyme amplification. A trifunctional double-stranded DNA (dsDNA) probe was designed including a methylation site for DNA MTase recognition, a complementary sequence of 8-17 DNAzyme for synthesizing DNAzyme, and a nicking site for nicking enzyme cleavage. Firstly, the trifunctional dsDNA probe was methylated by DNA MTase to form the methylated dsDNA. Subsequently, HpaII restriction endonuclease specifically cleaved the residue of unmethylated dsDNA. Next, under the action of polymerase and nicking enzyme, the methylared dsDNA initiated SDA, releasing numbers of 8-17 DNAzymes. Finally, the released 8-17 DNAzymes triggered DNAzyme amplification reaction to induce a significant fluorescence enhancement. This strategy could detect DNA MTase activity as low as 0.0082U/mL. Additionally, the strategy was successfully applied for evaluating the inhibitions of DNA MTase using two anticancer drugs, 5-azacytidine and 5-aza-2'-deoxycytidine. The results indicate the proposed strategy has a potential application in early cancer diagnosis and therapeutics.

  12. Intelligence amplification framework for enhancing scheduling processes

    NARCIS (Netherlands)

    Dobrkovic, Andrej; Liu, Luyao; Iacob, Maria-Eugenia; Hillegersberg, van Jos

    2016-01-01

    The scheduling process in a typical business environment consists of predominantly repetitive tasks that have to be completed in limited time and often containing some form of uncertainty. The intelligence amplification is a symbiotic relationship between a human and an intelligent agent. This partn

  13. Desert Amplification in a Warming Climate

    Science.gov (United States)

    Zhou, Liming

    2016-08-01

    Here I analyze the observed and projected surface temperature anomalies over land between 50°S-50°N for the period 1950–2099 by large-scale ecoregion and find strongest warming consistently and persistently seen over driest ecoregions such as the Sahara desert and the Arabian Peninsula during various 30-year periods, pointing to desert amplification in a warming climate. This amplification enhances linearly with the global mean greenhouse gases(GHGs) radiative forcing and is attributable primarily to a stronger GHGs-enhanced downward longwave radiation forcing reaching the surface over drier ecoregions as a consequence of a warmer and thus moister atmosphere in response to increasing GHGs. These results indicate that desert amplification may represent a fundamental pattern of global warming associated with water vapor feedbacks over land in low- and mid- latitudes where surface warming rates depend inversely on ecosystem dryness. It is likely that desert amplification might involve two types of water vapor feedbacks that maximize respectively in the tropical upper troposphere and near the surface over deserts, with both being very dry and thus extremely sensitive to changes of water vapor.

  14. Intelligence amplification framework for enhancing scheduling processes

    NARCIS (Netherlands)

    Dobrkovic, Andrej; Liu, Luyao; Iacob, Maria Eugenia; van Hillegersberg, Jos

    2016-01-01

    The scheduling process in a typical business environment consists of predominantly repetitive tasks that have to be completed in limited time and often containing some form of uncertainty. The intelligence amplification is a symbiotic relationship between a human and an intelligent agent. This

  15. Social amplification of risk: a conceptual framework

    Energy Technology Data Exchange (ETDEWEB)

    Kasperson, R.E.; Renn, O.; Slovic, P.; Brown, H.S.; Emel, J.; Goble, R.; Kasperson, J.X.; Ratick, S.

    1988-06-01

    One of the most perplexing problems in risk analysis is why some relatively minor risks or risk events, as assessed by technical experts, often elicit strong public concerns and result in substantial impacts upon society and economy. This article sets forth a conceptual framework that seeks to link systematically the technical assessment of risk with psychological, sociological, and cultural perspectives of risk perception and risk-related behavior. The main thesis is that hazards interact with psychological, social, institutional, and cultural processes in ways that may amplify or attenuate public responses to the risk or risk event. A structural description of the social amplification of risk is now possible. Amplification occurs at two stages: in the transfer of information about the risk, and in the response mechanisms of society. Signals about risk are processed by individual and social amplification stations, including the scientist who communicates the risk assessment, the news media, cultural groups, interpersonal networks, and others. Key steps of amplifications can be identified at each stage. The amplified risk leads to behavioral responses, which, in turn, result in secondary impacts. Models are presented that portray the elements and linkages in the proposed conceptual framework.

  16. A new evolutionary theory deduced mathematically from entropy amplification

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new evolutionary theory which is able to unite the present evolutionary debates is deduced mathematically from the principle of entropy amplification.It suggests that the extensive evolution is driven by the amplification of entropy,or microscopic diversity,and the biological evolution is driven by the amplification of biodiversity.Forming high hierarchies is the most important way for the amplification and brings out spontaneously three kinds of selection.This theory has some positive cultural meanings.

  17. Plasmonic Terahertz Amplification in Graphene-Based Asymmetric Hyperbolic Metamaterial

    Directory of Open Access Journals (Sweden)

    Igor Nefedov

    2015-05-01

    Full Text Available We propose and theoretically explore terahertz amplification, based on stimulated generation of plasmons in graphene asymmetric hyperbolic metamaterials (AHMM, strongly coupled to terahertz radiation. In contrast to the terahertz amplification in resonant nanocavities, AHMM provides a wide-band THz amplification without any reflection in optically thin graphene multilayers.

  18. Isothermal DNA amplification in bioanalysis: strategies and applications.

    Science.gov (United States)

    Kim, Joonyul; Easley, Christopher J

    2011-01-01

    Isothermal DNA amplification is an alternative to PCR-based amplification for point-of-care diagnosis. Since the early 1990s, the approach has been refined into a simple, rapid and cost-effective tool by means of several distinct strategies. Input signals have been diversified from DNA to RNA, protein or small organic molecules by translating these signals into input DNA before amplification, thus allowing assays on various classes of biomolecules. In situ detection of single biomolecules has been achieved using an isothermal method, leveraging localized signal amplification in an intact specimen. A few pioneering studies to develop a homogenous isothermal protein assay have successfully translated structure-switching of a probe upon target binding into input DNA for isothermal amplification. In addition to the detection of specific targets, isothermal methods have made whole-genome amplification of single cells possible owing to the unbiased, linear nature of the amplification process as well as the large size of amplified products given by ϕ29 DNA polymerase. These applications have been devised with the four isothermal amplification strategies covered in this review: strand-displacement amplification, rolling circle amplification, helicase-dependent amplification and recombinase polymerase amplification.

  19. Bioanalytical applications of isothermal nucleic acid amplification techniques.

    Science.gov (United States)

    Deng, Huimin; Gao, Zhiqiang

    2015-01-01

    The most popular in vitro nucleic acid amplification techniques like polymerase chain reaction (PCR) including real-time PCR are costly and require thermocycling, rendering them unsuitable for uses at point-of-care. Highly efficient in vitro nucleic acid amplification techniques using simple, portable and low-cost instruments are crucial in disease diagnosis, mutation detection and biodefense. Toward this goal, isothermal amplification techniques that represent a group of attractive in vitro nucleic acid amplification techniques for bioanalysis have been developed. Unlike PCR where polymerases are easily deactivated by thermally labile constituents in a sample, some of the isothermal nucleic acid amplification techniques, such as helicase-dependent amplification and nucleic acid sequence-based amplification, enable the detection of bioanalytes with much simplified protocols and with minimal sample preparations since the entire amplification processes are performed isothermally. This review focuses on the isothermal nucleic acid amplification techniques and their applications in bioanalytical chemistry. Starting off from their amplification mechanisms and significant properties, the adoption of isothermal amplification techniques in bioanalytical chemistry and their future perspectives are discussed. Representative examples illustrating the performance and advantages of each isothermal amplification technique are discussed along with some discussion on the advantages and disadvantages of each technique.

  20. Plasmonic Terahertz Amplification in Graphene-Based Asymmetric Hyperbolic Metamaterial

    OpenAIRE

    Igor Nefedov; Leonid Melnikov

    2015-01-01

    We propose and theoretically explore terahertz amplification, based on stimulated generation of plasmons in graphene asymmetric hyperbolic metamaterials (AHMM), strongly coupled to terahertz radiation. In contrast to the terahertz amplification in resonant nanocavities, AHMM provides a wide-band THz amplification without any reflection in optically thin graphene multilayers.

  1. Quantitation of viral load using real-time amplification techniques

    NARCIS (Netherlands)

    Niesters, H G

    2001-01-01

    Real-time PCR amplification techniques are currently used to determine the viral load in clinical samples for an increasing number of targets. Real-time PCR reduces the time necessary to generate results after amplification. In-house developed PCR and nucleic acid sequence-based amplification (NASBA

  2. RNA amplification for successful gene profiling analysis

    Directory of Open Access Journals (Sweden)

    Wang Ena

    2005-07-01

    Full Text Available Abstract The study of clinical samples is often limited by the amount of material available to study. While proteins cannot be multiplied in their natural form, DNA and RNA can be amplified from small specimens and used for high-throughput analyses. Therefore, genetic studies offer the best opportunity to screen for novel insights of human pathology when little material is available. Precise estimates of DNA copy numbers in a given specimen are necessary. However, most studies investigate static variables such as the genetic background of patients or mutations within pathological specimens without a need to assess proportionality of expression among different genes throughout the genome. Comparative genomic hybridization of DNA samples represents a crude exception to this rule since genomic amplification or deletion is compared among different specimens directly. For gene expression analysis, however, it is critical to accurately estimate the proportional expression of distinct RNA transcripts since such proportions directly govern cell function by modulating protein expression. Furthermore, comparative estimates of relative RNA expression at different time points portray the response of cells to environmental stimuli, indirectly informing about broader biological events affecting a particular tissue in physiological or pathological conditions. This cognitive reaction of cells is similar to the detection of electroencephalographic patterns which inform about the status of the brain in response to external stimuli. As our need to understand human pathophysiology at the global level increases, the development and refinement of technologies for high fidelity messenger RNA amplification have become the focus of increasing interest during the past decade. The need to increase the abundance of RNA has been met not only for gene specific amplification, but, most importantly for global transcriptome wide, unbiased amplification. Now gene

  3. Digital Microfluidics for Nucleic Acid Amplification

    Directory of Open Access Journals (Sweden)

    Beatriz Coelho

    2017-06-01

    Full Text Available Digital Microfluidics (DMF has emerged as a disruptive methodology for the control and manipulation of low volume droplets. In DMF, each droplet acts as a single reactor, which allows for extensive multiparallelization of biological and chemical reactions at a much smaller scale. DMF devices open entirely new and promising pathways for multiplex analysis and reaction occurring in a miniaturized format, thus allowing for healthcare decentralization from major laboratories to point-of-care with accurate, robust and inexpensive molecular diagnostics. Here, we shall focus on DMF platforms specifically designed for nucleic acid amplification, which is key for molecular diagnostics of several diseases and conditions, from pathogen identification to cancer mutations detection. Particular attention will be given to the device architecture, materials and nucleic acid amplification applications in validated settings.

  4. Amplification of postwildfire peak flow by debris

    Science.gov (United States)

    Kean, J. W.; McGuire, L. A.; Rengers, F. K.; Smith, J. B.; Staley, D. M.

    2016-08-01

    In burned steeplands, the peak depth and discharge of postwildfire runoff can substantially increase from the addition of debris. Yet methods to estimate the increase over water flow are lacking. We quantified the potential amplification of peak stage and discharge using video observations of postwildfire runoff, compiled data on postwildfire peak flow (Qp), and a physically based model. Comparison of flood and debris flow data with similar distributions in drainage area (A) and rainfall intensity (I) showed that the median runoff coefficient (C = Qp/AI) of debris flows is 50 times greater than that of floods. The striking increase in Qp can be explained using a fully predictive model that describes the additional flow resistance caused by the emergence of coarse-grained surge fronts. The model provides estimates of the amplification of peak depth, discharge, and shear stress needed for assessing postwildfire hazards and constraining models of bedrock incision.

  5. Parametric nanomechanical amplification at very high frequency.

    Science.gov (United States)

    Karabalin, R B; Feng, X L; Roukes, M L

    2009-09-01

    Parametric resonance and amplification are important in both fundamental physics and technological applications. Here we report very high frequency (VHF) parametric resonators and mechanical-domain amplifiers based on nanoelectromechanical systems (NEMS). Compound mechanical nanostructures patterned by multilayer, top-down nanofabrication are read out by a novel scheme that parametrically modulates longitudinal stress in doubly clamped beam NEMS resonators. Parametric pumping and signal amplification are demonstrated for VHF resonators up to approximately 130 MHz and provide useful enhancement of both resonance signal amplitude and quality factor. We find that Joule heating and reduced thermal conductance in these nanostructures ultimately impose an upper limit to device performance. We develop a theoretical model to account for both the parametric response and nonequilibrium thermal transport in these composite nanostructures. The results closely conform to our experimental observations, elucidate the frequency and threshold-voltage scaling in parametric VHF NEMS resonators and sensors, and establish the ultimate sensitivity limits of this approach.

  6. Gravito-magnetic amplification in cosmology

    CERN Document Server

    Tsagas, Christos G

    2009-01-01

    Magnetic fields interact with gravitational waves in various ways. We consider the coupling between the Weyl and the Maxwell fields in cosmology and study the effects of the former on the latter. The approach is fully analytical and the results are gauge-invariant. We show that the nature and the outcome of the gravito-magnetic interaction depends on the electric properties of the cosmic medium. When the conductivity is high, gravitational waves reduce the standard (adiabatic) decay rate of the B-field, leading to its superadiabatic amplification. In poorly conductive environments, on the other hand, Weyl-curvature distortions can result into the resonant amplification of large-scale cosmological magnetic fields. Driven by the gravitational waves, these B-fields oscillate with an amplitude that is found to diverge when the wavelengths of the two sources coincide. We present technical and physical aspects of the gravito-magnetic interaction and discuss its potential implications.

  7. Internal entanglement amplification by external interactions

    OpenAIRE

    2007-01-01

    We propose a scheme to control the level of entanglement between two fixed spin-1/2 systems by interaction with a third particle. For specific designs, entanglement is shown to be "pumped" into the system from the surroundings even when the spin-spin interaction within the system is small or nonexistent. The effect of the external particle on the system is introduced by including a dynamic spinor in the Hamiltonian. Controlled amplification of the internal entanglement to its maximum value is...

  8. Natural gas; Gas Natural

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Carlos A.; Moraes, Claudia C.D. [Eletricidade de Sao Paulo S.A. (ELETROPAULO), Sao Paulo, SP (Brazil); Fonseca, Carlos H.F. [Centrais Eletricas de Santa Catarina S.A., Florianopolis, SC (Brazil); Silva, Clecio Fabricio da; Alves, Ricardo P. [Companhia Paranaense de Energia (COPEL), Curitiba, PR (Brazil); Sposito, Edivaldo Soares; Hulle, Lutero [Espirito Santo Centrais Eletricas S.A. (ESCELSA), Vitoria, ES (Brazil); S. Martins, Icaro da [Centrais Eletricas do Norte do Brasil S.A. (ELETRONORTE), Belem, PA (Brazil); Vilhena, Joao Luiz S. de [Companhia Energetica de Minas Gerais (CEMIG), Belo Horizonte, MG (Brazil); Fagundes, Zaluar Aquino [Companhia Estadual de Energia Eletrica do Estado do Rio Grande do Sul, Porto Alegre, RS (Brazil)

    1996-12-31

    An increase in the consumption of natural gas in Brazil is an expected fact in what concerns energetic planning. This work presents the existing situation in what concerns natural gas utilization in the main world economies, as well as an analysis of the participation of this fuel among the energy final consumption per sources. The Brazilian consumption of natural gas is also analysed as well as the international agreement between Brazil and Bolivia for natural gas commercialization. Some legal, institutional and political aspects related to natural gas commercialization are also discussed. Finally, several benefits to be brought by the utilization of natural gas are presented 10 refs., 3 tabs.

  9. A mechanism for ramified rolling circle amplification

    Directory of Open Access Journals (Sweden)

    Smith James H

    2010-12-01

    Full Text Available Abstract Background Amplification of single-stranded DNA circles has wide utility for a variety of applications. The two-primer ramified rolling circle amplification (RAM reaction provides exponential DNA amplification under isothermal conditions, creating a regular laddered series of double-stranded DNA products. However, the molecular mechanism of the RAM reaction remains unexplained. Results A RAM reaction model predicts exponential accumulation of a double-stranded DNA product size series, and product-size ratios, that are consistent with observed RAM reaction products. The mechanism involves generation of a series of increasing size intermediate templates; those templates produce RAM products and recursively generate smaller intermediate templates. The model allows prediction of the number of rounds of circular template replication. Real-time RAM reaction data are consistent with the model. Analysis of RAM reaction products shows exponential growth limitation consistent with the model's predictions. Conclusions The model provides a rationale for the observed products of the RAM reaction, and the molecular yield among those products. Experimental results are consistent with the model.

  10. Nucleic acid amplification using microfluidic systems.

    Science.gov (United States)

    Chang, Chen-Min; Chang, Wen-Hsin; Wang, Chih-Hung; Wang, Jung-Hao; Mai, John D; Lee, Gwo-Bin

    2013-04-07

    In the post-human-genome-project era, the development of molecular diagnostic techniques has advanced the frontiers of biomedical research. Nucleic-acid-based technology (NAT) plays an especially important role in molecular diagnosis. However, most research and clinical protocols still rely on the manual analysis of individual samples by skilled technicians which is a time-consuming and labor-intensive process. Recently, with advances in microfluidic designs, integrated micro total-analysis-systems have emerged to overcome the limitations of traditional detection assays. These microfluidic systems have the capability to rapidly perform experiments in parallel and with a high-throughput which allows a NAT analysis to be completed in a few hours or even a few minutes. These features have a significant beneficial influence on many aspects of traditional biological or biochemical research and this new technology is promising for improving molecular diagnosis. Thus, in the foreseeable future, microfluidic systems developed for molecular diagnosis using NAT will become an important tool in clinical diagnosis. One of the critical issues for NAT is nucleic acid amplification. In this review article, recent advances in nucleic acid amplification techniques using microfluidic systems will be reviewed. Different approaches for fast amplification of nucleic acids for molecular diagnosis will be highlighted.

  11. Prognostic impact of HER-2 Subclonal Amplification in breast cancer.

    Science.gov (United States)

    Di Oto, Enrico; Brandes, Alba A; Cucchi, Maria C; Foschini, Maria P

    2017-06-02

    The presence of a limited number of cells with HER-2 amplification (Subclonal Amplification) in breast carcinomas is occasionally encountered, but its prognostic impact is poorly known. The purpose of this study is to evaluate the prognostic impact of HER-2 Subclonal Amplification in a retrospective series of breast cancers. Accordingly, 81 consecutive breast carcinomas showing HER-2 Subclonal Amplification were obtained from the histology files (case series). These cases were subdivided into two groups: (a) those cases in which the HER-2 Subclonal Amplification was consonant to the accepted criteria for amplification, showing clusters of amplified cells, and (b) those cases with rare HER-2 Subclonal Amplification that did not reflect the accepted criteria for amplification, showing scattered amplified cells only. The incidence of metastases and late recurrences of the case series was compared with a series composed of 109 consecutive cases, being HER-2 homogeneous (comprising 14 Amplified and 95 Non-Amplified cases), matched for grade and stage (control series). It appeared that cases showing Subclonal Amplification had an incidence of metastases intermediate between the cases Amplified and Non-Amplified. Specifically, Subclonal Amplification with clustered cells had a lower incidence of metastases than Amplified cases (12.9 versus 21.4%). On the contrary, Subclonal Amplification with scattered cells showed an incidence of metastases higher than Non-Amplified cases (14 versus 9.47%). In addition, patients Subclonal Amplification with clustered cells, who were treated with the specific monoclonal antibody, had a lower incidence of metastases than patients showing Subclonal Amplification with scattered cells, who did not receive target therapy. These data, together with those recently published, indicate that Subclonal Amplification has an impact on prognosis and should be taken into consideration to correctly plan the treatment of breast cancer patients.

  12. The μ-RWELL: A compact, spark protected, single amplification-stage MPGD

    Science.gov (United States)

    Poli Lener, M.; Bencivenni, G.; de Olivera, R.; Felici, G.; Franchino, S.; Gatta, M.; Maggi, M.; Morello, G.; Sharma, A.

    2016-07-01

    In this work we present two innovative architectures of resistive MPGDs based on the WELL-amplification concept: - the micro-Resistive WELL (μ-RWELL) is a compact spark-protected single amplification-stage Micro-Pattern Gas Detector (MPGD). The amplification stage, realized with a structure very similar to a GEM foil (called WELL), is embedded through a resistive layer in the readout board. A cathode electrode, defining the gas conversion/drift gap, completes the detector mechanics. The new architecture, showing an excellent space resolution, 50 μm, is a very compact device, robust against discharges and exhibiting a large gain (>104), simple to construct and easy for engineering and then suitable for large area tracking devices as well as digital calorimeters. - the Fast Timing Micro-pattern (FTM): a new device with an architecture based on a stack of several coupled full-resistive layers where drift and multiplication stages (WELL type) alternate in the structure. The signals from each multiplication stage can be read out from any external readout boards through the capacitive couplings, providing a signal with a gain of 104-105. The main advantage of this new device is the improvement of the timing provided by the competition of the ionization processes in the different drift regions, which can be exploited for fast timing at the high luminosity accelerators (e.g. HL-LHC upgrade) as well as for applications like medical imaging.

  13. Loop mediated isothermal amplification: An innovative gene amplification technique for animal diseases

    Directory of Open Access Journals (Sweden)

    Pravas Ranjan Sahoo

    2016-05-01

    Full Text Available India being a developing country mainly depends on livestock sector for its economy. However, nowadays, there is emergence and reemergence of more transboundary animal diseases. The existing diagnostic techniques are not so quick and with less specificity. To reduce the economy loss, there should be a development of rapid, reliable, robust diagnostic technique, which can work with high degree of sensitivity and specificity. Loop mediated isothermal amplification assay is a rapid gene amplification technique that amplifies nucleic acid under an isothermal condition with a set of designed primers spanning eight distinct sequences of the target. This assay can be used as an emerging powerful, innovative gene amplification diagnostic tool against various pathogens of livestock diseases. This review is to highlight the basic concept and methodology of this assay in livestock disease.

  14. Loop mediated isothermal amplification: An innovative gene amplification technique for animal diseases.

    Science.gov (United States)

    Sahoo, Pravas Ranjan; Sethy, Kamadev; Mohapatra, Swagat; Panda, Debasis

    2016-05-01

    India being a developing country mainly depends on livestock sector for its economy. However, nowadays, there is emergence and reemergence of more transboundary animal diseases. The existing diagnostic techniques are not so quick and with less specificity. To reduce the economy loss, there should be a development of rapid, reliable, robust diagnostic technique, which can work with high degree of sensitivity and specificity. Loop mediated isothermal amplification assay is a rapid gene amplification technique that amplifies nucleic acid under an isothermal condition with a set of designed primers spanning eight distinct sequences of the target. This assay can be used as an emerging powerful, innovative gene amplification diagnostic tool against various pathogens of livestock diseases. This review is to highlight the basic concept and methodology of this assay in livestock disease.

  15. Gas gain study for CO sub 2 /isobutane mixtures

    CERN Document Server

    Okuno, H; Nakamura, Y; Fujii, K; Hoshina, K; Kato, Y; Kurihara, Y; Kuroiwa, H; Nitoh, O

    2000-01-01

    We have studied gas amplification properties of a proportional tube filled with CO sub 2 /isobutane gas mixtures. The gas gain was measured for X- and beta-rays as a function of the anode-wire surface field and was used to estimate gain variation along 4.6 m-long stereo anode wires of our proposed central drift chamber for JLC. During the gas gain study, we observed a strong saturation effect for point ionizations.

  16. Whole Genome Amplification from Blood Spot Samples.

    Science.gov (United States)

    Sørensen, Karina Meden

    2015-01-01

    Whole genome amplification is an invaluable technique when working with DNA extracted from blood spots, as the DNA obtained from this source often is too limited for extensive genetic analysis. Two techniques that amplify the entire genome are common. Here, both are described with focus on the benefits and drawbacks of each system. However, in order to obtain the best possible WGA result the quality of input DNA extracted from the blood spot is essential, but also time consumption, flexibility in format and elution volume and price of the technology are factors influencing system choice. Here, three DNA extraction techniques are described and the above aspects are compared between the systems.

  17. Amplification Without Inversion in Semiconductor Quantum Dot

    Science.gov (United States)

    Hajibadali, A.; Abbasian, K.; Rostami, A.

    In this paper, we have realized amplification without inversion (AWI) in quantum dot (QD). A Y-type four-level system of InxGa1-xN quantum dot has been obtained and investigated for AWI. It has been shown that, with proper setting of control fields' amplitude, we can obtain reasonable gain. With proper setting of phase difference of control fields and probe field, we can obtain considerable gain in resonant wavelength. We have designed this system by solving the Schrödinger-Poisson equations for InxGa1-xN quantum dot in GaN substrate, self-consistently.

  18. Amplification of curvature perturbations in cyclic cosmology

    Science.gov (United States)

    Zhang, Jun; Liu, Zhi-Guo; Piao, Yun-Song

    2010-12-01

    We analytically and numerically show that through the cycles with nonsingular bounce, the amplitude of curvature perturbation on a large scale will be amplified and the power spectrum will redden. In some sense, this amplification will eventually destroy the homogeneity of the background, which will lead to the ultimate end of cycles of the global universe. We argue that for the model with increasing cycles, it might be possible that a fissiparous multiverse will emerge after one or several cycles, in which the cycles will continue only at corresponding local regions.

  19. Amplification and characterization of eukaryotic structural genes.

    Science.gov (United States)

    Maniatis, T; Efstratiadis, A; Sim, G K; Kafatos, F

    1978-05-01

    An approach to the study of eukaryotic structural genes which are differentially expressed during development is described. This approach involves the isolation and amplification of mRNA sequences by in vitro conversion of mRNA to double-stranded cDNA followed by molecular cloning in bacterial plasmids. This procedure provides highly specific hybridization probes that can be used to identify genes and their contiguous DNA sequences in genomic DNA, and to detect specific RNA transcripts during development. The nature of the method allows the isolation of individual mRNA sequences from a complex population of molecules at different stages of development.

  20. Amplification Effects and Unconventional Monetary Policies

    Directory of Open Access Journals (Sweden)

    Cécile BASTIDON GILLES

    2012-02-01

    Full Text Available Global financial crises trigger off amplification effects, which allow relatively small shocks to propagate through the whole financial system. For this reason, the range of Central banks policies is now widening beyond conventional monetary policies and lending of last resort. The aim of this paper is to establish a rule for this practice. The model is based on the formalization of funding conditions in various types of markets. We conduct a comprehensive analysis of the “unconventional monetary policies”, and especially quantify government bonds purchases by the Central bank.

  1. Advances in isothermal amplification: novel strategies inspired by biological processes.

    Science.gov (United States)

    Li, Jia; Macdonald, Joanne

    2015-02-15

    Nucleic acid amplification is an essential process in biological systems. The in vitro adoption of this process has resulted in powerful techniques that underpin modern molecular biology. The most common tool is polymerase chain reaction (PCR). However, the requirement for a thermal cycler has somewhat limited applications of this classic nucleic acid amplification technique. Isothermal amplification, on the other hand, obviates the use of a thermal cycler because reactions occur at a single temperature. Isothermal amplification methods are diverse, but all have been developed from an understanding of natural nucleic acid amplification processes. Here we review current isothermal amplification methods as classified by their enzymatic mechanisms. We compare their advantages, disadvantages, efficiencies, and applications. Finally, we mention some new developments associated with this technology, and consider future possibilities in molecular engineering and recombinant technologies that may develop from an appreciation of the molecular biology of natural systems.

  2. Mechanism of seasonal Arctic sea ice evolution and Arctic amplification

    OpenAIRE

    Kim, Kwang-Yul; Hamlington, Benjamin D.; Na, Hanna; Kim, Jinju

    2016-01-01

    Sea ice loss is proposed as a primary reason for the Arctic amplification, although the physical mechanism of the Arctic amplification and its connection with sea ice melting is still in debate. In the present study, monthly ERA-Interim reanalysis data are analyzed via cyclostationary empirical orthogonal function analysis to understand the seasonal mechanism of sea ice loss in the Arctic Ocean and the Arctic amplification. While sea ice loss is widespread over much of the p...

  3. Space Optical Communications Using Laser Beam Amplification

    Science.gov (United States)

    Agrawal, Govind

    2015-01-01

    The Space Optical Communications Using Laser Beam Amplification (SOCLBA) project will provide a capability to amplify a laser beam that is received in a modulating retro-reflector (MRR) located in a satellite in low Earth orbit. It will also improve the pointing procedure between Earth and spacecraft terminals. The technology uses laser arrays to strengthen the reflected laser beam from the spacecraft. The results of first year's work (2014) show amplification factors of 60 times the power of the signal beam. MMRs are mirrors that reflect light beams back to the source. In space optical communications, a high-powered laser interrogator beam is directed from the ground to a satellite. Within the satellite, the beam is redirected back to ground using the MMR. In the MMR, the beam passes through modulators, which encode a data signal onto the returning beam. MMRs can be used in small spacecraft for optical communications. The SOCLBA project is significant to NASA and small spacecraft due to its application to CubeSats for optical data transmission to ground stations, as well as possible application to spacecraft for optical data transmission.

  4. Experimental noiseless linear amplification using weak measurements

    Science.gov (United States)

    Ho, Joseph; Boston, Allen; Palsson, Matthew; Pryde, Geoff

    2016-09-01

    The viability of quantum communication schemes rely on sending quantum states of light over long distances. However, transmission loss can degrade the signal strength, adding noise. Heralded noiseless amplification of a quantum signal can provide a solution by enabling longer direct transmission distances and by enabling entanglement distillation. The central idea of heralded noiseless amplification—a conditional modification of the probability distribution over photon number of an optical quantum state—is suggestive of a parallel with weak measurement: in a weak measurement, learning partial information about an observable leads to a conditional back-action of a commensurate size. Here we experimentally investigate the application of weak, or variable-strength, measurements to the task of heralded amplification, by using a quantum logic gate to weakly couple a small single-optical-mode quantum state (the signal) to an ancilla photon (the meter). The weak measurement is carried out by choosing the measurement basis of the meter photon and, by conditioning on the meter outcomes, the signal is amplified. We characterise the gain of the amplifier as a function of the measurement strength, and use interferometric methods to show that the operation preserves the coherence of the signal.

  5. Magnetic Field Amplification in Young Galaxies

    CERN Document Server

    Schober, Jennifer; Klessen, Ralf S

    2013-01-01

    The Universe at present is highly magnetized, with fields of the order of a few 10^-5 G and coherence lengths larger than 10 kpc in typical galaxies like the Milky Way. We propose that the magnetic field was amplified to this values already during the formation and the early evolution of the galaxies. Turbulence in young galaxies is driven by accretion as well as by supernova (SN) explosions of the first generation of stars. The small-scale dynamo can convert the turbulent kinetic energy into magnetic energy and amplify very weak primordial magnetic seed fields on short timescales. The amplification takes place in two phases: in the kinematic phase the magnetic field grows exponentially, with the largest growth on the smallest non-resistive scale. In the following non-linear phase the magnetic energy is shifted towards larger scales until the dynamo saturates on the turbulent forcing scale. To describe the amplification of the magnetic field quantitatively we model the microphysics in the interstellar medium ...

  6. Loop-mediated isothermal amplification for detection of nucleic acids.

    Science.gov (United States)

    Tanner, Nathan A; Evans, Thomas C

    2014-01-06

    Sequence-specific isothermal nucleic acid amplification techniques are ideally suited for use in molecular diagnostic applications because they do not require thermal cycling equipment and the reactions are typically fast. One of the most widely cited isothermal techniques is termed loop-mediated isothermal amplification (LAMP). This protocol allows amplification times as fast as 5 to 10 min. Furthermore, various methodologies to detect amplification have been applied to LAMP to increase its utility for the point-of-care market. Basic LAMP protocols are provided herein for detection of specific DNA and RNA targets, along with a method to perform multiplex LAMP reactions, permitting even greater flexibility from this powerful technique.

  7. Stability of the laminar boundary layer for an imperfect gas

    Science.gov (United States)

    Gasperas, G.

    The linear perturbation equations are derived for the general case of a compressible imperfect gas characterized by an equation of state utilizing a compressibility factor. The specific case of the Beattie-Bridgeman gas is chosen for calculation. Amplification curves calculated using the Beattie-Bridgeman equation of state for two representative flat plate boundary layers are presented.

  8. Micropattern gas detectors The CMS MSGC project and gaseous pixel detector applications

    CERN Document Server

    Bellazzini, R; Gariano, G; Latronico, L; Lumb, N; Moggi, A; Reale, S; Spandre, G; Massai, M M; Spezziga, M A; Toropin, A N; Costa, E; Soffitta, P; Pacella, D

    2001-01-01

    We report recent results from the development and testing of two types of micropattern gas detectors-micro-strip gas chambers and GEM- based devices with two types of pixel read-out. Thirty-two micro- strip gas chambers were tested in a high intensity hadron beam as a milestone for CERN's Compact Muon Solenoid (CMS) experiment. The detectors were operated with voltage settings corresponding to 98% hit detection efficiency at CMS for a total high intensity exposure period of 493 h. All of the requirements expected by the milestone- gain stability, number of lost strips, spark rate, etc.-were met, with wide margins. In a separate investigation, we have coupled PCB pixel read-out planes to GEM foils. In one case, 2 mm*2 mm pixels were fanned out to individual discriminators and scalers to provide very fast (2 MHz/pixel) read-out; this system has been used as an imaging device to provide diagnostic information in fusion experiments. The second type of device used smaller pixels (200 mu m squares) and a Flash-ADC ...

  9. Seismic Wave Amplification in 3D Alluvial Basins: 3D/1D Amplification Ratios from Fast Multipole BEM Simulations

    CERN Document Server

    Fajardo, Kristel C Meza; Chaillat, Stéphanie; Lenti, Luca

    2016-01-01

    In this work, we study seismic wave amplification in alluvial basins having 3D standard geometries through the Fast Multipole Boundary Element Method in the frequency domain. We investigate how much 3D amplification differs from the 1D (horizontal layering) case. Considering incident fields of plane harmonic waves, we examine the relationships between the amplification level and the most relevant physical parameters of the problem (impedance contrast, 3D aspect ratio, vertical and oblique incidence of plane waves). The FMBEM results show that the most important parameters for wave amplification are the impedance contrast and the so-called equivalent shape ratio. Using these two parameters, we derive simple rules to compute the fundamental frequency for various 3D basin shapes and the corresponding 3D/1D amplification factor for 5% damping. Effects on amplification due to 3D basin asymmetry are also studied and incorporated in the derived rules.

  10. Turbulent amplification of supernova magnetic fields in the laboratory

    Science.gov (United States)

    Gregori, Gianluca

    2014-10-01

    X-ray and radio observations of the supernova remnant Cassiopeia A reveal the presence of magnetic fields about 100 times stronger than those in the surrounding interstellar medium. Field coincident with the outer shock probably arises through a non-linear feedback process involving cosmic rays. The origin of the large magnetic field in the interior of the remnant is less clear but it is probably stretched and amplified by turbulent motions. Turbulence may be generated by hydrodynamic instability at the contact discontinuity between the supernova ejecta and the circumstellar gas. However, optical observations of Cassiopeia A indicate that the ejecta are interacting with a highly inhomogeneous, dense circumstellar cloud bank formed prior to the supernova explosion. We have conducted a series of laboratory experiments using high power laser facilities in order to reproduce the essential features of the supernova shock interacting with strong density perturbations. Our results indicate the magnetic field is amplified when the shock interacts with a plastic grid. We show that our experimental results can explain the observed synchrotron emission in the interior of the remnant. These experiments provide an example of magnetic field amplification by turbulence in plasmas, a physical process thought to occur in many astrophysical phenomena.

  11. Broadening and Amplification of an Infrared Femtosecond Pulse for Optical Parametric Chirped-Pulse Amplification

    Institute of Scientific and Technical Information of China (English)

    WANG He-Lin; YANG Ai-Jun; LENG Yu-Xin

    2011-01-01

    A high-average-power diode-pumped narrowband regenerative chirped pulse amplifier is developed using the thin-rod Nd:YAG laser architecture for optical parametric chirped-pulse amplification (OPCPA).The effect of the etalons on the amplified pulse in the regenerative cavity is studied experimentally and theoretically.By inserting glass etalons of thickness 1 mm and 5 mm into the regenerative cavity,the pre-stretching pulse from an (O)ffner stretcher is further broadened to above 200ps,which matches the amplification windows of the signal pulses in OPCPA and is suitable for use as a pump source in the OPCPA system.The bandwidth of the amplified pulse is 1.5 nm,and an output energy of 2mJ is achieved at a repetition rate of 10 Hz.Optical parametric chirped pulse amplification (OPCPA)[1-4] has attracted a great deal of attention as the most promising technique for generating ultrashort ultrahigh-peak-power laser pulses because of its very broad gain bandwidth,negligible thermal load on the nonlinear crystal,and extremely high singlepass gain as compared to amplifiers based on laser gain media.For efficient amplification and high fidelity of dispersion compensation in OPCPA,a femtosecond seed pulse is first stretched to several tens of picoseconds with a bulk grating stretcher or a fiber stretcher.%A high-average-power diode-pumped narrowband regenerative chirped pulse amplifier is developed using the thin-rod Nd:YAG laser architecture for optical parametric chirped-pulse amplification (OPCPA). The effect of the etalons on the amplified pulse in the regenerative cavity is studied experimentally and theoretically. By inserting glass etalons of thickness 1 mm and 5 mm into the regenerative cavity, the pre-stretching pulse from an (O)finer stretcher is further broadened to above 200 ps, which matches the amplification windows of the signal pulses in OPCPA and is suitable for use as a pump source in the OPCPA system. The bandwidth of the amplified pulse is 1.5 nm, and an

  12. Gas turbine

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ok Ryong

    2004-01-15

    This book introduces gas turbine cycle explaining general thing of gas turbine, full gas turbine cycle, Ericson cycle and Brayton cycle, practical gas turbine cycle without pressure loss, multiaxial type gas turbine cycle and special gas turbine cycle, application of basic theory on a study on suction-cooling gas turbine cycle with turbo-refrigerating machine using the bleed air, and general performance characteristics of the suction-cooling gas turbine cycle combined with absorption-type refrigerating machine.

  13. Control and amplification of cortical neurodynamics

    Science.gov (United States)

    Liljenstroem, Hans; Aronsson, P.

    1999-03-01

    We investigate different mechanisms for the control and amplification of cortical neurodynamics, using a neural network model of a three layered cortical structure. We show that different dynamical states can be obtained by changing a control parameter of the input-output relation, or by changing the noise level. Point attractor, limit cycle, and strange attractor dynamics occur at different values of the control parameter. For certain, optimal noise levels, system performance is maximized, analogous to stochastic resonance phenomena. Noise can also be used to induce different dynamical states. A few noisy network units distributed in a network layer can result in global synchronous oscillations, or waves of activity moving across the network. We further demonstrate that fast synchronization of network activity can be obtained by implementing electromagnetic interactions between network units.

  14. Controlled Microwave Heating Accelerates Rolling Circle Amplification.

    Science.gov (United States)

    Yoshimura, Takeo; Suzuki, Takamasa; Mineki, Shigeru; Ohuchi, Shokichi

    2015-01-01

    Rolling circle amplification (RCA) generates single-stranded DNAs or RNA, and the diverse applications of this isothermal technique range from the sensitive detection of nucleic acids to analysis of single nucleotide polymorphisms. Microwave chemistry is widely applied to increase reaction rate as well as product yield and purity. The objectives of the present research were to apply microwave heating to RCA and indicate factors that contribute to the microwave selective heating effect. The microwave reaction temperature was strictly controlled using a microwave applicator optimized for enzymatic-scale reactions. Here, we showed that microwave-assisted RCA reactions catalyzed by either of the four thermostable DNA polymerases were accelerated over 4-folds compared with conventional RCA. Furthermore, the temperatures of the individual buffer components were specifically influenced by microwave heating. We concluded that microwave heating accelerated isothermal RCA of DNA because of the differential heating mechanisms of microwaves on the temperatures of reaction components, although the overall reaction temperatures were the same.

  15. Anisotropic metamaterials with simultaneous attenuation and amplification

    CERN Document Server

    Mackay, Tom G

    2015-01-01

    Anisotropic metamaterials that are neither wholly dissipative nor wholly active at a specific frequency are permitted by classical electromagnetic theory. Well-established formalisms for the homogenization of particulate composite materials indicate that such a metamaterial may be conceptualized quite simply as a random mixture of electrically small spheroidal particles of at least two different isotropic dielectric materials, one of which must be dissipative but the other active. The realization of this metametarial is influenced by the volume fraction, spatial distribution, particle shape and size, and the relative permittivities of the component materials. Metamaterials displaying both dissipation and amplification at the same frequency with more complicated linear as well as nonlinear constitutive properties are possible.

  16. Dispersion compensation in chirped pulse amplification systems

    Science.gov (United States)

    Bayramian, Andrew James; Molander, William A.

    2014-07-15

    A chirped pulse amplification system includes a laser source providing an input laser pulse along an optical path. The input laser pulse is characterized by a first temporal duration. The system also includes a multi-pass pulse stretcher disposed along the optical path. The multi-pass pulse stretcher includes a first set of mirrors operable to receive input light in a first plane and output light in a second plane parallel to the first plane and a first diffraction grating. The pulse stretcher also includes a second set of mirrors operable to receive light diffracted from the first diffraction grating and a second diffraction grating. The pulse stretcher further includes a reflective element operable to reflect light diffracted from the second diffraction grating. The system further includes an amplifier, a pulse compressor, and a passive dispersion compensator disposed along the optical path.

  17. Integrated Amplification Microarrays for Infectious Disease Diagnostics

    Directory of Open Access Journals (Sweden)

    Darrell P. Chandler

    2012-11-01

    Full Text Available This overview describes microarray-based tests that combine solution-phase amplification chemistry and microarray hybridization within a single microfluidic chamber. The integrated biochemical approach improves microarray workflow for diagnostic applications by reducing the number of steps and minimizing the potential for sample or amplicon cross-contamination. Examples described herein illustrate a basic, integrated approach for DNA and RNA genomes, and a simple consumable architecture for incorporating wash steps while retaining an entirely closed system. It is anticipated that integrated microarray biochemistry will provide an opportunity to significantly reduce the complexity and cost of microarray consumables, equipment, and workflow, which in turn will enable a broader spectrum of users to exploit the intrinsic multiplexing power of microarrays for infectious disease diagnostics.

  18. Magnetic field amplification in turbulent astrophysical plasmas

    CERN Document Server

    Federrath, Christoph

    2016-01-01

    Magnetic fields play an important role in astrophysical accretion discs, and in the interstellar and intergalactic medium. They drive jets, suppress fragmentation in star-forming clouds and can have a significant impact on the accretion rate of stars. However, the exact amplification mechanisms of cosmic magnetic fields remain relatively poorly understood. Here I start by reviewing recent advances in the numerical and theoretical modelling of the 'turbulent dynamo', which may explain the origin of galactic and inter-galactic magnetic fields. While dynamo action was previously investigated in great detail for incompressible plasmas, I here place particular emphasis on highly compressible astrophysical plasmas, which are characterised by strong density fluctuations and shocks, such as the interstellar medium. I find that dynamo action works not only in subsonic plasmas, but also in highly supersonic, compressible plasmas, as well as for low and high magnetic Prandtl numbers. I further present new numerical simu...

  19. Amplification sans bruit d'images optiques

    Science.gov (United States)

    Gigan, S.; Delaubert, V.; Lopez, L.; Treps, N.; Maitre, A.; Fabre, C.

    2004-11-01

    Nous utilisons un Oscillateur Paramétrique Optique (OPO) pompé sous le seuil dans le but d'amplifier une image multimode transverse sans dégradation du rapport signal à bruit. Le dispositif expérimental met en œuvre un OPO de type II triplement résonant et semi-confocal pour le faisceau amplifié. L'existence d'effets quantiques lors de l'amplification multimode dans un tel dispositif a été montrée expérimentalement. Plus généralement, ceci nous a amené à étudier les propriétés quantiques transverses des faisceaux lumineux amplifiés. Une telle étude peut trouver des applications non seulement en imagerie, mais également dans le traitement quantique de l'information.

  20. Raman amplification in optical communication systems

    DEFF Research Database (Denmark)

    Kjær, Rasmus

    2008-01-01

    Fiber Raman amplifiers are investigated with the purpose of identifying new applications and limitations for their use in optical communication systems. Three main topics are investigated, namely: New applications of dispersion compensating Raman amplifiers, the use Raman amplification to increase...... fiberbaserede Raman-forstærkere med henblik på at identificere både deres begrænsninger og nye anvendelsesmuligheder i optiske kommunikationssystemer. En numerisk forstærkermodel er blevet udviklet for bedre at forstå forstærkerens dynamik, dens gain- og støjbegrænsninger. Modellen bruges til at forudsige...... forstærkerens statiske og dynamiske egenskaber, og det eftervises at dens resultater er i god overensstemmelse med eksperimentelle forstærkermålinger. Dispersions-kompenserende fiber er på grund af sin store udbredelse og fiberens høje Raman gain effektivitet et meget velegnet Raman gain-medium. Tre nye...

  1. Magnetic Field Amplification and Blazar Flares

    CERN Document Server

    Chen, Xuhui; Fossati, Giovanni; Pohl, Martin

    2013-01-01

    Recent multiwavelength observations of PKS 0208-512 by SMARTS, Fermi, and Swift revealed that gamma-ray and optical light curves of this flat spectrum radio quasars are highly correlated, but with an exception of one large optical flare having no corresponding gamma-ray activity or even detection. On the other hand, recent advances in SNRs observations and plasma simulations both reveal that magnetic field downstream of astrophysical shocks can be largely amplified beyond simple shock compression. These amplifications, along with their associated particle acceleration, might contribute to blazar flares, including the peculiar flare of PKS 0208-512. Using our time dependent multizone blazar emission code, we evaluate several scenarios that may represent such phenomena. This code combines Monte Carlo method that tracks the radiative processes including inverse Compton scattering, and Fokker-Planck equation that follows the cooling and acceleration of particles. It is a comprehensive time dependent code that ful...

  2. Protein Misfolding Cyclic Amplification of Infectious Prions.

    Science.gov (United States)

    Moda, Fabio

    2017-01-01

    Transmissible spongiform encephalopathies, or prion diseases, are a group of incurable disorders caused by the accumulation of an abnormally folded prion protein (PrP(Sc)) in the brain. According to the "protein-only" hypothesis, PrP(Sc) is the infectious agent able to propagate the disease by acting as a template for the conversion of the correctly folded prion protein (PrP(C)) into the pathological isoform. Recently, the mechanism of PrP(C) conversion has been mimicked in vitro using an innovative technique named protein misfolding cyclic amplification (PMCA). This technology represents a great tool for studying diverse aspects of prion biology in the field of basic research and diagnosis. Moreover, PMCA can be expanded for the study of the misfolding process associated to other neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, and frontotemporal lobar degeneration. © 2017 Elsevier Inc. All rights reserved.

  3. Targeting HER2 amplifications in gastric cancer

    Directory of Open Access Journals (Sweden)

    Ung L

    2014-01-01

    Full Text Available Lawson Ung, Terence C Chua, Neil D Merrett Department of Surgery, South Western Sydney Upper GI Surgical Unit, Bankstown Hospital, University of Western Sydney, Sydney, NSW, Australia Abstract: While multimodality treatments, including neoadjuvant and adjuvant chemotherapy or chemoradiation, have become the global standard of care in patients with locally advanced and metastatic gastric cancers (GCs, long-term outcomes for patients remain poor. This reflects the aggressive tumor biology of GCs and occult nature of the disease, often presenting in its advanced stages, as well as the challenges of developing effective targeted therapy to treat this disease. The Trastuzumab for Gastric Cancer trial demonstrates that the addition of human epidermal growth factor 2 (HER2 monoclonal antibody trastuzumab to standard chemotherapy regimen consisting of 5-fluorouracil (5-FU or capecitabine with cisplatin results in significant improvement in overall and progression-free survival. Although questions remain regarding the best methods by which to determine HER2 mutation positivity and amplification, through immunohistochemistry or in situ hybridization, and whether trastuzumab is effective for locally advanced, nonmetastatic GC in an adjuvant setting, the trial has led to a surge of clinical trials investigating the potential role of other HER2- and non-HER2-targeted therapies to improve patient outcomes. This review will discuss our current understanding of GC pathogenesis, current available treatments, and the potential impact that targeting HER2 amplifications may have in our efforts to individualize and optimize cancer care in GC individuals. Keywords: Personalized cancer therapy, surgical oncology, gastrectomy, adjuvant treatment, targeted therapies

  4. Mutualism breakdown by amplification of Wolbachia genes.

    Science.gov (United States)

    Chrostek, Ewa; Teixeira, Luis

    2015-02-01

    Most insect species are associated with vertically transmitted endosymbionts. Because of the mode of transmission, the fitness of these symbionts is dependent on the fitness of the hosts. Therefore, these endosymbionts need to control their proliferation in order to minimize their cost for the host. The genetic bases and mechanisms of this regulation remain largely undetermined. The maternally inherited bacteria of the genus Wolbachia are the most common endosymbionts of insects, providing some of them with fitness benefits. In Drosophila melanogaster, Wolbachia wMelPop is a unique virulent variant that proliferates massively in the hosts and shortens their lifespan. The genetic bases of wMelPop virulence are unknown, and their identification would allow a better understanding of how Wolbachia levels are regulated. Here we show that amplification of a region containing eight Wolbachia genes, called Octomom, is responsible for wMelPop virulence. Using Drosophila lines selected for carrying Wolbachia with different Octomom copy numbers, we demonstrate that the number of Octomom copies determines Wolbachia titers and the strength of the lethal phenotype. Octomom amplification is unstable, and reversion of copy number to one reverts all the phenotypes. Our results provide a link between genotype and phenotype in Wolbachia and identify a genomic region regulating Wolbachia proliferation. We also prove that these bacteria can evolve rapidly. Rapid evolution by changes in gene copy number may be common in endosymbionts with a high number of mobile elements and other repeated regions. Understanding wMelPop pathogenicity and variability also allows researchers to better control and predict the outcome of releasing mosquitoes transinfected with this variant to block human vector-borne diseases. Our results show that transition from a mutualist to a pathogen may occur because of a single genomic change in the endosymbiont. This implies that there must be constant selection on

  5. Short-Pulse Amplification by Strongly-Coupled Brillouin Scattering

    CERN Document Server

    Edwards, Matthew R; Mikhailova, Julia M; Fisch, Nathaniel J

    2016-01-01

    We examine the feasibility of strongly-coupled stimulated Brillouin scattering as a mechanism for the plasma-based amplification of sub-picosecond pulses. In particular, we use fluid theory and particle-in-cell simulations to compare the relative advantages of Raman and Brillouin amplification over a broad range of achievable parameters.

  6. A Theoretical Evaluation of Optical Parametric Amplification in BBO Crystal

    Institute of Scientific and Technical Information of China (English)

    邵敏; 薛绍林; 林尊琪

    2005-01-01

    The noncollinear optical parametric amplification in BBO crystal is theoretically investigated. The phase matching angle, gain bandwidth, optimal noncollinear angle and conversion efficiency for both type-Ⅰ and type-Ⅱ BBO are simulated. The numerical simulation results are important to the practical optical parametric amplification experiments with BBO crystal.

  7. Phase Sensitive Amplification using Parametric Processes in Optical Fibers

    DEFF Research Database (Denmark)

    Kang, Ning

    , in specific, the design and optimization of such phase sensitive amplifiers (PSAs). For phase sensitive amplification in highly nonlinear fibers, optima points of operation have been identified for both the standard and the novel high stimulated Brillouin scattering (SBS) threshold highly nonlinear fiber....... Finally, preliminary simulations were carried out to investigate the inline amplification properties of such PSAs, and their pulse shaping capabilities....

  8. Generation of recombinant pestiviruses using a full genome amplification strategy

    DEFF Research Database (Denmark)

    Rasmussen, Thomas Bruun; Reimann, Ilona; Uttenthal, Åse

    Aim Complete genome amplification of viral RNA provides a new tool for generation of modified pestiviruses. We have recently reported a full genome amplification strategy for direct recovery of infectious pestivirus (Rasmussen et al., 2008). This comprised rescue of BDV strain “Gifhorn” from a full......-length RT-PCR amplicon demonstrating that long RT-PCR can be used for direct generation of an infectious pestivirus. The strategy is not limited to amplification of BDV “Gifhorn”, but can be further utilized for amplification of a diverse selection of pestivirus strains and for the generation of modified...... the amplicons were prepared for cloning into low-copy vectors to produce new infectious cDNA clones. Conclusions Using this full genome amplification strategy the efforts in producing new viral variants can be expedited and focused on a variety of other viral strains and hence is not limited to the availability...

  9. Parametric Analog Signal Amplification Applied to Nanoscale CMOS Technologies

    CERN Document Server

    Oliveira, João P

    2012-01-01

    This book is dedicated to the analysis of parametric amplification with special emphasis on the MOS discrete-time implementation. This implementation is demonstrated by the presentation of several circuits where the MOS parametric amplifier cell is used: small gain amplifier, comparator with embedded pre-amplification, discrete-time mixer/IIR-Filter, and analog-to-digital converter (ADC).  Experimental results are shown to validate the overall design technique. Provides the complete theoretical analysis, supported by electrical simulations, of the parametric amplification technique in both continuous time and discrete time domains; Describes the design flow of an ADC fully based on discrete-time parametric amplification in CMOS technology; Presents a high speed time-interleaved pipeline ADC, based on parametric MOS amplification techniques described, complementing theory discussed with experimental results.

  10. Clinical application of somatosensory amplification in psychosomatic medicine

    Directory of Open Access Journals (Sweden)

    Nakao Mutsuhiro

    2007-10-01

    Full Text Available Abstract Many patients with somatoform disorders are frequently encountered in psychosomatic clinics as well as in primary care clinics. To assess such patients objectively, the concept of somatosensory amplification may be useful. Somatosensory amplification refers to the tendency to experience a somatic sensation as intense, noxious, and disturbing. It may have a role in a variety of medical conditions characterized by somatic symptoms that are disproportionate to demonstrable organ pathology. It may also explain some of the variability in somatic symptomatology found among different patients with the same serious medical disorder. It has been assessed with a self-report questionnaire, the Somatosensory Amplification Scale. This instrument was developed in a clinical setting in the U.S., and the reliability and validity of the Japanese and Turkish versions have been confirmed as well. Many studies have attempted to clarify the specific role of somatosensory amplification as a pathogenic mechanism in somatization. It has been reported that somatosensory amplification does not correlate with heightened sensitivity to bodily sensations and that emotional reactivity exerts its influence on somatization via a negatively biased reporting style. According to our recent electroencephalographic study, somatosensory amplification appears to reflect some aspects of long-latency cognitive processing rather than short-latency interoceptive sensitivity. The concept of somatosensory amplification can be useful as an indicator of somatization in the therapy of a broad range of disorders, from impaired self-awareness to various psychiatric disorders. It also provides useful information for choosing appropriate pharmacological or psychological therapy. While somatosensory amplification has a role in the presentation of somatic symptoms, it is closely associated with other factors, namely, anxiety, depression, and alexithymia that may also influence the same

  11. The current status of the Gas Electron Multiplier (GEM) research at Kasetsart University, Thailand

    Science.gov (United States)

    Kumpiranon, P.; Kulasri, K.; Rittirong, A.; Saenboonruang, K.

    2017-06-01

    During the past decade, Gas Electron Multiplier (GEM) detectors have been greatly developed and utilized in numbers of applications including advanced nuclear and particle researches, medical imaging, astrophysics, and neutron detection for national security. Our GEM research group at the Department of Applied Radiation and Isotopes, Faculty of Science, Kasetsart University, Thailand, realized in its excellent properties/potentials and started extensive researches on GEM detectors. To build a strong foundation on our research group, two 10 cm × 10 cm triple GEM detectors were characterized on their important properties including absolute gains and detection uniformity. Moreover, to widen applications of the GEM detector, our group had modified the GEM detector by introducing either solid or gaseous neutron converters to the detector so that the detector could effectively detect neutrons. These modifications included coating a thin film of 10B and natB to the GEM drift cathode for thermal neutron detection and flowing a gas mixture of He/CO2 (80:20 and 70:30) and C4H10/He/CO2 (7:70:23) for fast neutron detection. Results showed that the modified GEM-based neutron detector could detect both types of neutrons with different relative efficiencies and gains depending on thicknesses and types of neutron converters. This article discusses basic knowledge of the GEM detector, construction and testing procedures, results, and discussion.

  12. Nucleic acid amplification: Alternative methods of polymerase chain reaction.

    Science.gov (United States)

    Fakruddin, Md; Mannan, Khanjada Shahnewaj Bin; Chowdhury, Abhijit; Mazumdar, Reaz Mohammad; Hossain, Md Nur; Islam, Sumaiya; Chowdhury, Md Alimuddin

    2013-10-01

    Nucleic acid amplification is a valuable molecular tool not only in basic research but also in application oriented fields, such as clinical medicine development, infectious diseases diagnosis, gene cloning and industrial quality control. A comperehensive review of the literature on the principles, applications, challenges and prospects of different alternative methods of polymerase chain reaction (PCR) was performed. PCR was the first nucleic acid amplification method. With the advancement of research, a no of alternative nucleic acid amplification methods has been developed such as loop mediated isothermal amplification, nucleic acid sequence based amplification, strand displacement amplification, multiple displacement amplification. Most of the alternative methods are isothermal obviating the need for thermal cyclers. Though principles of most of the alternate methods are relatively complex than that of PCR, they offer better applicability and sensitivity in cases where PCR has limitations. Most of the alternate methods still have to prove themselves through extensive validation studies and are not available in commercial form; they pose the potentiality to be used as replacements of PCR. Continuous research is going on in different parts of the world to make these methods viable technically and economically.

  13. Mechanism of Gene Amplification via Yeast Autonomously Replicating Sequences

    Directory of Open Access Journals (Sweden)

    Shelly Sehgal

    2015-01-01

    Full Text Available The present investigation was aimed at understanding the molecular mechanism of gene amplification. Interplay of fragile sites in promoting gene amplification was also elucidated. The amplification promoting sequences were chosen from the Saccharomyces cerevisiae ARS, 5S rRNA regions of Plantago ovata and P. lagopus, proposed sites of replication pausing at Ste20 gene locus of S. cerevisiae, and the bend DNA sequences within fragile site FRA11A in humans. The gene amplification assays showed that plasmid bearing APS from yeast and human beings led to enhanced protein concentration as compared to the wild type. Both the in silico and in vitro analyses were pointed out at the strong bending potential of these APS. In addition, high mitotic stability and presence of TTTT repeats and SAR amongst these sequences encourage gene amplification. Phylogenetic analysis of S. cerevisiae ARS was also conducted. The combinatorial power of different aspects of APS analyzed in the present investigation was harnessed to reach a consensus about the factors which stimulate gene expression, in presence of these sequences. It was concluded that the mechanism of gene amplification was that AT rich tracts present in fragile sites of yeast serve as binding sites for MAR/SAR and DNA unwinding elements. The DNA protein interactions necessary for ORC activation are facilitated by DNA bending. These specific bindings at ORC promote repeated rounds of DNA replication leading to gene amplification.

  14. Kinetic Hairpin Oligonucleotide Blockers for Selective Amplification of Rare Mutations

    Science.gov (United States)

    Jia, Yanwei; Sanchez, J. Aquiles; Wangh, Lawrence J.

    2014-01-01

    Detection of rare mutant alleles in an excess of wild type alleles is increasingly important in cancer diagnosis. Several methods for selective amplification of a mutant allele via the polymerase chain reaction (PCR) have been reported, but each of these methods has its own limitations. A common problem is that Taq DNA polymerase errors early during amplification generate false positive mutations which also accumulate exponentially. In this paper, we described a novel method using hairpin oligonucleotide blockers that can selectively inhibit the amplification of wild type DNA during LATE-PCR amplification. LATE-PCR generates double-stranded DNA exponentially followed by linear amplification of single-stranded DNA. The efficiency of the blocker is optimized by adjusting the LATE-PCR temperature cycling profile. We also demonstrate that it is possible to minimize false positive signals caused by Taq DNA polymerase errors by using a mismatched excess primer plus a modified PCR profile to preferentially enrich for mutant target sequences prior to the start of the exponential phase of LATE-PCR amplification. In combination these procedures permit amplification of specific KRAS mutations in the presence of more than 10,000 fold excess of wild type DNA without false positive signals. PMID:25082368

  15. Quality control for quantitative PCR based on amplification compatibility test.

    Science.gov (United States)

    Tichopad, Ales; Bar, Tzachi; Pecen, Ladislav; Kitchen, Robert R; Kubista, Mikael; Pfaffl, Michael W

    2010-04-01

    Quantitative qPCR is a routinely used method for the accurate quantification of nucleic acids. Yet it may generate erroneous results if the amplification process is obscured by inhibition or generation of aberrant side-products such as primer dimers. Several methods have been established to control for pre-processing performance that rely on the introduction of a co-amplified reference sequence, however there is currently no method to allow for reliable control of the amplification process without directly modifying the sample mix. Herein we present a statistical approach based on multivariate analysis of the amplification response data generated in real-time. The amplification trajectory in its most resolved and dynamic phase is fitted with a suitable model. Two parameters of this model, related to amplification efficiency, are then used for calculation of the Z-score statistics. Each studied sample is compared to a predefined reference set of reactions, typically calibration reactions. A probabilistic decision for each individual Z-score is then used to identify the majority of inhibited reactions in our experiments. We compare this approach to univariate methods using only the sample specific amplification efficiency as reporter of the compatibility. We demonstrate improved identification performance using the multivariate approach compared to the univariate approach. Finally we stress that the performance of the amplification compatibility test as a quality control procedure depends on the quality of the reference set.

  16. A mechanism of gene amplification driven by small DNA fragments.

    Directory of Open Access Journals (Sweden)

    Kuntal Mukherjee

    Full Text Available DNA amplification is a molecular process that increases the copy number of a chromosomal tract and often causes elevated expression of the amplified gene(s. Although gene amplification is frequently observed in cancer and other degenerative disorders, the molecular mechanisms involved in the process of DNA copy number increase remain largely unknown. We hypothesized that small DNA fragments could be the trigger of DNA amplification events. Following our findings that small fragments of DNA in the form of DNA oligonucleotides can be highly recombinogenic, we have developed a system in the yeast Saccharomyces cerevisiae to capture events of chromosomal DNA amplification initiated by small DNA fragments. Here we demonstrate that small DNAs can amplify a chromosomal region, generating either tandem duplications or acentric extrachromosomal DNA circles. Small fragment-driven DNA amplification (SFDA occurs with a frequency that increases with the length of homology between the small DNAs and the target chromosomal regions. SFDA events are triggered even by small single-stranded molecules with as little as 20-nt homology with the genomic target. A double-strand break (DSB external to the chromosomal amplicon region stimulates the amplification event up to a factor of 20 and favors formation of extrachromosomal circles. SFDA is dependent on Rad52 and Rad59, partially dependent on Rad1, Rad10, and Pol32, and independent of Rad51, suggesting a single-strand annealing mechanism. Our results reveal a novel molecular model for gene amplification, in which small DNA fragments drive DNA amplification and define the boundaries of the amplicon region. As DNA fragments are frequently found both inside cells and in the extracellular environment, such as the serum of patients with cancer or other degenerative disorders, we propose that SFDA may be a common mechanism for DNA amplification in cancer cells, as well as a more general cause of DNA copy number variation

  17. Complementary weak-value amplification with concatenated postselections

    CERN Document Server

    Viza, Gerardo I; Liu, Wei-Tao; Howell, John C

    2016-01-01

    We measure a transverse momentum kick in a Sagnac interferometer using weak-value amplification with two postselections. The first postselection is controlled by a polarization dependent phase mismatch between both paths of a Sagnac interferometer and the second postselection is controlled by a polarizer at the exit port. By monitoring the darkport of the interferometer, we study the complementary amplification of the concatenated postselections, where the polarization extinction ratio is greater than the contrast of the spatial interference. In this case, we find an improvement in the amplification of the signal of interest by introducing a second postselection to the system.

  18. Limits for superfocusing with finite evanescent wave amplification

    CERN Document Server

    Gordon, Reuven

    2011-01-01

    Perfect lensing using negative refractive index materials and radiationless electromagnetic interference both provide extreme subwavelength focusing by "amplifying" evanescent wave components that are usually lost. This paper provides a relation between the achievable focus spot size, the amplification available and the focal length. This may be considered as a revised version of Abbe's diffraction limit for focusing systems that have evanescent wave amplification. It is useful in comparing the amplification achieved in various subwavelength focusing implementations, as well as determining when it is better to use existing near-field techniques, such as simple diffraction from an aperture or slit, than to attempt complicated superfocusing.

  19. Fluorescence amplification by electrochemically deposited silver nanowires with fractal architecture.

    Science.gov (United States)

    Goldys, Ewa M; Drozdowicz-Tomsia, Krystyna; Xie, Fang; Shtoyko, Tanya; Matveeva, Eva; Gryczynski, Ignacy; Gryczynski, Zygmunt

    2007-10-10

    Electrochemically deposited silver structures with nanowires 50-100 nm in diameter show high fluorescence amplification and strongly reduced fluorescence lifetimes. Both quantities depend on the structure thickness. With increasing thickness the fluorescence amplification proportionally increases and the fluorescence lifetime decreases. This thickness dependence is caused by fluorophore interaction with a system of plasmon excitations in coupled nanowires extending over micrometer size regions. Thus the amplification is attributed to a combination of extended structure area and strong plasmonic coupling between nanowires which also help to radiatively scatter the fluorescence emission.

  20. Backward Raman amplification in the long-wavelength infrared

    Science.gov (United States)

    Johnson, L. A.; Gordon, D. F.; Palastro, J. P.; Hafizi, B.

    2017-03-01

    The wealth of work in backward Raman amplification in plasma has focused on the extreme intensity limit; however, backward Raman amplification may also provide an effective and practical mechanism for generating intense, broad bandwidth, long-wavelength infrared radiation (LWIR). An electromagnetic simulation coupled with a relativistic cold fluid plasma model is used to demonstrate the generation of picosecond pulses at a wavelength of 10 μm with terawatt powers through backward Raman amplification. The effects of collisional damping, Landau damping, pump depletion, and wave breaking are examined, as well as the resulting design considerations for an LWIR Raman amplifier.

  1. Local Runup Amplification By Resonant Wave Interactions

    CERN Document Server

    Stefanakis, Themistoklis; Dutykh, Denys

    2011-01-01

    Until now the analysis of long wave runup on a plane beach has been focused on finding its maximum value, failing to capture the existence of resonant regimes. One-dimensional numerical simulations in the framework of the Nonlinear Shallow Water Equations (NSWE) are used to investigate the Boundary Value Problem (BVP) for plane and non-trivial beaches. Monochromatic waves, as well as virtual wave-gage recordings from real tsunami simulations, are used as forcing conditions to the BVP. Resonant phenomena between the incident wavelength and the beach slope are found to occur, which result in enhanced runup of non-leading waves. The evolution of energy reveals the existence of a quasi-periodic state for the case of sinusoidal waves, the energy level of which, as well as the time required to reach that state, depend on the incident wavelength for a given beach slope. Dispersion is found to slightly reduce the value of maximum runup, but not to change the overall picture. Runup amplification occurs for both leadin...

  2. Protein misfolding cyclic amplification of infectious prions.

    Science.gov (United States)

    Morales, Rodrigo; Duran-Aniotz, Claudia; Diaz-Espinoza, Rodrigo; Camacho, Manuel V; Soto, Claudio

    2012-06-28

    Prions are proteinaceous infectious agents responsible for the transmission of prion diseases. The lack of a procedure for cultivating prions in the laboratory has been a major limitation to the study of the unorthodox nature of this infectious agent and the molecular mechanism by which the normal prion protein (PrP(C)) is converted into the abnormal isoform (PrP(Sc)). Protein misfolding cyclic amplification (PMCA), described in detail in this protocol, is a simple, fast and efficient methodology to mimic prion replication in the test tube. PMCA involves incubating materials containing minute amounts of infectious prions with an excess of PrP(C) and boosting the conversion by cycles of sonication to fragment the converting units, thereby leading to accelerated prion replication. PMCA is able to detect the equivalent of a single molecule of infectious PrP(Sc) and propagate prions that maintain high infectivity, strain properties and species specificity. A single PMCA assay takes little more than 3 d to replicate a large amount of prions, which could take years in an in vivo situation. Since its invention 10 years ago, PMCA has helped to answer fundamental questions about this intriguing infectious agent and has been broadly applied in research areas that include the food industry, blood bank safety and human and veterinary disease diagnosis.

  3. A PCR amplification method without DNA extraction.

    Science.gov (United States)

    Li, Hongwei; Xu, Haiyue; Zhao, Chunjiang; Sulaiman, Yiming; Wu, Changxin

    2011-02-01

    To develop a simple and inexpensive method for direct PCR amplification of animal DNA from tissues, we optimized different components and their concentration in lysis buffer systems. Finally, we acquired the optimized buffer system composed of 10 mmol tris(hydroxymethyl)aminomethane (Tris)-Cl (pH 8.0), 2 mmol ethylene diamine tetraacetic (EDTA) (pH 8.0), 0.2 mol NaCl and 200 μg/mL Proteinase K. Interestingly, the optimized buffer is also very effective when working with common human sample types, including blood, buccal cells and hair. The direct PCR method requires fewer reagents (Tris-Cl, EDTA, Protease K and NaCl) and less incubation time (only 35 min). The cost of treating every sample is less than $0.02, and all steps can be completed on a thermal cycler in a 96-well format. So, the proposed method will significantly improve high-throughput PCR-based molecular assays in animal systems and in common human sample types.

  4. Kinematic amplification strategies in plants and engineering

    Science.gov (United States)

    Charpentier, Victor; Hannequart, Philippe; Adriaenssens, Sigrid; Baverel, Olivier; Viglino, Emmanuel; Eisenman, Sasha

    2017-06-01

    While plants are primarily sessile at the organismal level, they do exhibit a vast array of movements at the organ or sub-organ level. These movements can occur for reasons as diverse as seed dispersal, nutrition, protection or pollination. Their advanced mechanisms generate a myriad of movement typologies, many of which are not fully understood. In recent years, there has been a renewal of interest in understanding the mechanical behavior of plants from an engineering perspective, with an interest in developing novel applications by up-sizing these mechanisms from the micro- to the macro-scale. This literature review identifies the main strategies used by plants to create and amplify movements and anatomize the most recent mechanical understanding of compliant engineering mechanics. The paper ultimately demonstrates that plant movements, rooted in compliance and multi-functionality, can effectively inspire better kinematic/adaptive structures and materials. In plants, the actuators and the deployment structures are fused into a single system. The understanding of those natural movements therefore starts with an exploration of mechanisms at the origins of movements. Plant movements, whether slow or fast, active or passive, reversible or irreversible, are presented and detailed for their mechanical significance. With a focus on displacement amplification, the most recent promising strategies for actuation and adaptive systems are examined with respect to the mechanical principles of shape morphing plant tissues.

  5. KASER: Knowledge Amplification by Structured Expert Randomization.

    Science.gov (United States)

    Rubin, Stuart H; Murthy, S N Jayaram; Smith, Michael H; Trajković, Ljiljana

    2004-12-01

    In this paper and attached video, we present a third-generation expert system named Knowledge Amplification by Structured Expert Randomization (KASER) for which a patent has been filed by the U.S. Navy's SPAWAR Systems Center, San Diego, CA (SSC SD). KASER is a creative expert system. It is capable of deductive, inductive, and mixed derivations. Its qualitative creativity is realized by using a tree-search mechanism. The system achieves creative reasoning by using a declarative representation of knowledge consisting of object trees and inheritance. KASER computes with words and phrases. It possesses a capability for metaphor-based explanations. This capability is useful in explaining its creative suggestions and serves to augment the capabilities provided by the explanation subsystems of conventional expert systems. KASER also exhibits an accelerated capability to learn. However, this capability depends on the particulars of the selected application domain. For example, application domains such as the game of chess exhibit a high degree of geometric symmetry. Conversely, application domains such as the game of craps played with two dice exhibit no predictable pattern, unless the dice are loaded. More generally, we say that domains whose informative content can be compressed to a significant degree without loss (or with relatively little loss) are symmetric. Incompressible domains are said to be asymmetric or random. The measure of symmetry plus the measure of randomness must always sum to unity.

  6. Controlled Microwave Heating Accelerates Rolling Circle Amplification.

    Directory of Open Access Journals (Sweden)

    Takeo Yoshimura

    Full Text Available Rolling circle amplification (RCA generates single-stranded DNAs or RNA, and the diverse applications of this isothermal technique range from the sensitive detection of nucleic acids to analysis of single nucleotide polymorphisms. Microwave chemistry is widely applied to increase reaction rate as well as product yield and purity. The objectives of the present research were to apply microwave heating to RCA and indicate factors that contribute to the microwave selective heating effect. The microwave reaction temperature was strictly controlled using a microwave applicator optimized for enzymatic-scale reactions. Here, we showed that microwave-assisted RCA reactions catalyzed by either of the four thermostable DNA polymerases were accelerated over 4-folds compared with conventional RCA. Furthermore, the temperatures of the individual buffer components were specifically influenced by microwave heating. We concluded that microwave heating accelerated isothermal RCA of DNA because of the differential heating mechanisms of microwaves on the temperatures of reaction components, although the overall reaction temperatures were the same.

  7. Small Sample Whole-Genome Amplification

    Energy Technology Data Exchange (ETDEWEB)

    Hara, C A; Nguyen, C P; Wheeler, E K; Sorensen, K J; Arroyo, E S; Vrankovich, G P; Christian, A T

    2005-09-20

    Many challenges arise when trying to amplify and analyze human samples collected in the field due to limitations in sample quantity, and contamination of the starting material. Tests such as DNA fingerprinting and mitochondrial typing require a certain sample size and are carried out in large volume reactions; in cases where insufficient sample is present whole genome amplification (WGA) can be used. WGA allows very small quantities of DNA to be amplified in a way that enables subsequent DNA-based tests to be performed. A limiting step to WGA is sample preparation. To minimize the necessary sample size, we have developed two modifications of WGA: the first allows for an increase in amplified product from small, nanoscale, purified samples with the use of carrier DNA while the second is a single-step method for cleaning and amplifying samples all in one column. Conventional DNA cleanup involves binding the DNA to silica, washing away impurities, and then releasing the DNA for subsequent testing. We have eliminated losses associated with incomplete sample release, thereby decreasing the required amount of starting template for DNA testing. Both techniques address the limitations of sample size by providing ample copies of genomic samples. Carrier DNA, included in our WGA reactions, can be used when amplifying samples with the standard purification method, or can be used in conjunction with our single-step DNA purification technique to potentially further decrease the amount of starting sample necessary for future forensic DNA-based assays.

  8. Gas and Gas Pains

    Science.gov (United States)

    ... problems with gas if you: Are lactose or gluten intolerant Eat a diet rich in fruits, vegetables, whole grains and legumes Drink carbonated beverages Have a chronic intestinal condition, such as irritable bowel syndrome or inflammatory bowel disease Neither age nor sex ...

  9. The Amplification in FEL with Inhomogeneous Magnetic Field

    CERN Document Server

    Oganesyan, K B

    2016-01-01

    The gain in a plane wiggler with inhomogeneous magnetic field is calculated.. It is shown, that the account of inhomogenity of the magnetic field leads to appearance of additional peaks in the amplification

  10. Amplification options for patients with mixed hearing loss.

    NARCIS (Netherlands)

    Zwartenkot, J.W.; Snik, A.F.M.; Mylanus, E.A.M.; Mulder, J.J.S.

    2014-01-01

    OBJECTIVES: To compare amplification options for patients with mixed hearing loss. Devices tested include percutaneous and transcutaneous bone conductors (BCDs) and middle ear implants with their actuator directly coupled to the cochlea. SETTING: Tertiary academic medical center. METHOD AND PARTICIP

  11. Nonlinear Zel'dovich effect: Parametric amplification from medium rotation

    CERN Document Server

    Faccio, Daniele

    2016-01-01

    The interaction of light with rotating media has attracted recent interest for both fundamental and applied studies including rotational Doppler shift measurements. It is also possible to obtain amplification through the scattering of light with orbital angular momentum from a rotating and absorbing cylinder, as proposed by Zel'dovich more than 40 years ago. This amplification mechanism has never been observed experimentally yet has connections to other fields such as Penrose superradiance in rotating black holes. Here we propose a nonlinear optics system whereby incident light carrying orbital angular momentum drives parametric interaction in a rotating medium. The crystal rotation is shown to take the phase-mismatched parametric interaction with negligible energy exchange at zero rotation to amplification for sufficiently large rotation rates. The amplification is shown to result from breaking of anti-PT symmetry induced by the medium rotation.

  12. Amplification and flagellin typing of pseudomonas aeruginosa by molecular method

    Directory of Open Access Journals (Sweden)

    gholamreza goudarzi

    2011-08-01

    Conclusion: This method could be utilized to determine flagellated (Motile and non-flagellated strains of P. aeruginosa, genotyping, amplification of full coding sequence of fliC gene in order to clone and express recombinant flagellin protein.

  13. Whole genome amplification: Use of advanced isothermal method

    African Journals Online (AJOL)

    Yomi

    2010-12-29

    Dec 29, 2010 ... 5Department of Animal Science, College of Agriculture & Natural Resources, University of Tehran, Karaj ..... All of these factors produce nonspecific amplification ... PCRs on the same WGA yield, allelic dropout is not locus-.

  14. Studies of nondegenerate, quasi-phase-matched optical parametric amplification

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence Livermore National Laboratory

    2004-03-18

    We have performed extensive numerical studies of quasi-phase-matched optical parametric amplification with the aim to improve its nondegenerate spectral bandwidth. Our multi-section fan-out design calculations indicate a 35-fold increase in spectral bandwidth.

  15. Nonlinear Zel'dovich Effect: Parametric Amplification from Medium Rotation

    Science.gov (United States)

    Faccio, Daniele; Wright, Ewan M.

    2017-03-01

    The interaction of light with rotating media has attracted recent interest for both fundamental and applied studies including rotational Doppler shift measurements. It is also possible to obtain amplification through the scattering of light with orbital angular momentum from a rotating and absorbing cylinder, as proposed by Zel'dovich more than forty years ago. This amplification mechanism has never been observed experimentally yet has connections to other fields such as Penrose superradiance in rotating black holes. Here we propose a nonlinear optics system whereby incident light carrying orbital angular momentum drives parametric interaction in a rotating medium. The crystal rotation is shown to take the phase-mismatched parametric interaction with negligible energy exchange at zero rotation to amplification for sufficiently large rotation rates. The amplification is shown to result from breaking of anti-P T symmetry induced by the medium rotation.

  16. Pulse Distortion in Saturated Fiber Optical Parametric Chirped Pulse Amplification

    DEFF Research Database (Denmark)

    Lali-Dastjerdi, Zohreh; Da Ros, Francesco; Rottwitt, Karsten

    2012-01-01

    Fiber optical parametric chirped pulse amplification is experimentally compared for different chirped pulses in the picosecond regime. The amplified chirped pulses show distortion appearing as pedestals after recompression when the amplifier is operated in saturation.......Fiber optical parametric chirped pulse amplification is experimentally compared for different chirped pulses in the picosecond regime. The amplified chirped pulses show distortion appearing as pedestals after recompression when the amplifier is operated in saturation....

  17. Engineering targeted chromosomal amplifications in human breast epithelial cells.

    Science.gov (United States)

    Springer, Simeon; Yi, Kyung H; Park, Jeenah; Rajpurohit, Anandita; Price, Amanda J; Lauring, Josh

    2015-07-01

    Chromosomal amplifications are among the most common genetic alterations found in human cancers. However, experimental systems to study the processes that lead to specific, recurrent amplification events in human cancers are lacking. Moreover, some common amplifications, such as that at 8p11-12 in breast cancer, harbor multiple driver oncogenes, which are poorly modeled by conventional overexpression approaches. We sought to develop an experimental system to model recurrent chromosomal amplification events in human cell lines. Our strategy is to use homologous-recombination-mediated gene targeting to deliver a dominantly selectable, amplifiable marker to a specified chromosomal location. We used adeno-associated virus vectors to target human MCF-7 breast cancer cells at the ZNF703 locus, in the recurrent 8p11-12 amplicon, using the E. coli inosine monophosphate dehydrogenase (IMPDH) enzyme as a marker. We applied selective pressure using IMPDH inhibitors. Surviving clones were found to have increased copy number of ZNF703 (average 2.5-fold increase) by droplet digital PCR and FISH. Genome-wide array comparative genomic hybridization confirmed that amplifications had occurred on the short arm of chromosome 8, without changes on 8q or other chromosomes. Patterns of amplification were variable and similar to those seen in primary human breast cancers, including "sawtooth" patterns, distal copy number loss, and large continuous regions of copy number gain. This system will allow study of the cis- and trans-acting factors that are permissive for chromosomal amplification and provide a model to analyze oncogene cooperativity in amplifications harboring multiple candidate driver genes.

  18. Aerosol Lidar for the Relative Backscatter Amplification Measurements

    Science.gov (United States)

    Razenkov, Igor A.; Banakh, Victor A.; Nadeev, Alexander I.

    2016-06-01

    Backscatter amplification presents only in a turbulent atmosphere, when the laser beam is propagates twice through the same inhomogeneities. We proposed technical solution to detect backscatter amplification. An aerosol micro pulse lidar with a beam expansion via receiving telescope was built to study this effect. Our system allows simultaneous detection of two returns from the same scattering volume: exactly on the axis of the laser beam and off the axis.

  19. Methods for microbial DNA extraction from soil for PCR amplification

    OpenAIRE

    Yeates C; Gillings, MR; Davison AD; Altavilla N; Veal DA

    1998-01-01

    Amplification of DNA from soil is often inhibited by co-purified contaminants. A rapid, inexpensive, large-scale DNA extraction method involving minimal purification has been developed that is applicable to various soil types (1). DNA is also suitable for PCR amplification using various DNA targets. DNA was extracted from 100g of soil using direct lysis with glass beads and SDS followed by potassium acetate precipitation, polyethylene glycol precipitation, phenol extraction and isopropanol pr...

  20. The emergence of surface-based Arctic amplification

    Directory of Open Access Journals (Sweden)

    M. C. Serreze

    2008-07-01

    Full Text Available Rises in surface and lower troposphere air temperatures through the 21st century are projected to be especially pronounced over the Arctic Ocean during the cold season. This Arctic amplification is largely driven by loss of the sea ice cover, allowing for strong heat transfers from the ocean to the atmosphere. Consistent with observed reductions in sea ice extent, fields from the NCEP/NCAR reanalysis suggest emergence of surface-based Arctic amplification in the last decade.

  1. Controllable Amplification of Entanglement for Two Qutrits under Decoherence

    Institute of Scientific and Technical Information of China (English)

    ZHENG Qiang; XIE Xiao-Yao; ZHI Qi-Jun; REN Zhong-Zhou

    2011-01-01

    Entanglement dynamics of a two-qutrit Heisenberg spin chain with the external magnetic fields and DM interaction under the intrinsic decoherence is investigated. Depending on whether there is inhomogeneous magnetic field,the entanglement amplification, i.e. the phenomenon that the finally stable entanglement is bigger than that of the initial one, is found for one kind of initial states. The reasons for the controllable entanglement amplification are discussed.

  2. The emergence of surface-based Arctic amplification

    OpenAIRE

    SERREZE, M. C.; A. P. Barrett; J. C. Stroeve; Kindig, D. N.; Holland, M. M.

    2009-01-01

    Rises in surface and lower troposphere air temperatures through the 21st century are projected to be especially pronounced over the Arctic Ocean during the cold season. This Arctic amplification is largely driven by loss of the sea ice cover, allowing for strong heat transfers from the ocean to the atmosphere. Consistent with observed reductions in sea ice extent, fields from both the NCEP/NCAR and JRA-25 reanalyses point to emergence of surface-based Arctic amplification in the last decade.

  3. Targeting MET Amplification as a New Oncogenic Driver

    Energy Technology Data Exchange (ETDEWEB)

    Kawakami, Hisato [Department of Medical Oncology, Kinki University Faculty of Medicine, 377-2 Ohno-higashi, Osaka-Sayama, Osaka 589-8511 (Japan); Okamoto, Isamu, E-mail: okamotoi@kokyu.med.kyushu-u.ac.jp [Department of Medical Oncology, Kinki University Faculty of Medicine, 377-2 Ohno-higashi, Osaka-Sayama, Osaka 589-8511 (Japan); Center for Clinical and Translational Research, Kyushu University Hospital, 3-1-1 Maidashi, Higashiku, Fukuoka 812-8582 (Japan); Okamoto, Wataru [Department of Medical Oncology, Kinki University Faculty of Medicine, 377-2 Ohno-higashi, Osaka-Sayama, Osaka 589-8511 (Japan); Division of Transrlational Research, Exploratory Oncology Research & Clinical Trial Center, National Cancer Center, 6-5-1 Kashiwanoha, Kashiwa, Chiba 277-8577 (Japan); Tanizaki, Junko [Department of Medical Oncology, Kinki University Faculty of Medicine, 377-2 Ohno-higashi, Osaka-Sayama, Osaka 589-8511 (Japan); Lowe Center for Thoracic Oncology, Dana-Farber Cancer Institute, HIM223, 450 Brookline Avenue, Boston, MA 02215 (United States); Nakagawa, Kazuhiko [Department of Medical Oncology, Kinki University Faculty of Medicine, 377-2 Ohno-higashi, Osaka-Sayama, Osaka 589-8511 (Japan); Nishio, Kazuto [Department of Genome Biology, Kinki University Faculty of Medicine, 377-2 Ohno-higashi, Osaka-Sayama, Osaka 589-8511 (Japan)

    2014-07-22

    Certain genetically defined cancers are dependent on a single overactive oncogene for their proliferation and survival, a phenomenon known as “oncogene addiction”. A new generation of drugs that selectively target such “driver oncogenes” manifests a clinical efficacy greater than that of conventional chemotherapy in appropriate genetically defined patients. MET is a proto-oncogene that encodes a receptor tyrosine kinase, and aberrant activation of MET signaling occurs in a subset of advanced cancers as result of various genetic alterations including gene amplification, polysomy, and gene mutation. Our preclinical studies have shown that inhibition of MET signaling either with the small-molecule MET inhibitor crizotinib or by RNA interference targeted to MET mRNA resulted in marked antitumor effects in cancer cell lines with MET amplification both in vitro and in vivo. Furthermore, patients with non-small cell lung cancer or gastric cancer positive for MET amplification have shown a pronounced clinical response to crizotinib. Accumulating preclinical and clinical evidence thus suggests that MET amplification is an “oncogenic driver” and therefore a valid target for treatment. However, the prevalence of MET amplification has not been fully determined, possibly in part because of the difficulty in evaluating gene amplification. In this review, we provide a rationale for targeting this genetic alteration in cancer therapy.

  4. Integration of isothermal amplification methods in microfluidic devices: Recent advances.

    Science.gov (United States)

    Giuffrida, Maria Chiara; Spoto, Giuseppe

    2017-04-15

    The integration of nucleic acids detection assays in microfluidic devices represents a highly promising approach for the development of convenient, cheap and efficient diagnostic tools for clinical, food safety and environmental monitoring applications. Such tools are expected to operate at the point-of-care and in resource-limited settings. The amplification of the target nucleic acid sequence represents a key step for the development of sensitive detection protocols. The integration in microfluidic devices of the most popular technology for nucleic acids amplifications, polymerase chain reaction (PCR), is significantly limited by the thermal cycling needed to obtain the target sequence amplification. This review provides an overview of recent advances in integration of isothermal amplification methods in microfluidic devices. Isothermal methods, that operate at constant temperature, have emerged as promising alternative to PCR and greatly simplify the implementation of amplification methods in point-of-care diagnostic devices and devices to be used in resource-limited settings. Possibilities offered by isothermal methods for digital droplet amplification are discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Theory of phase-mixing amplification in an optomechanical system

    Science.gov (United States)

    Ockeloen-Korppi, C. F.; Heikkilä, T. T.; Sillanpää, M. A.; Massel, F.

    2017-09-01

    The investigation of the ultimate limits imposed by quantum mechanics on amplification represents an important topic both on a fundamental level and from the perspective of potential applications. We discuss here a novel regime for bosonic linear amplifiers—beside phase-insensitive and phase-sensitive amplification—which we term here phase-mixing amplification. Furthermore, we show that phase-mixing amplification can be realised in a cavity optomechanical setup, constituted by a mechanical resonator which is dispersively coupled to an optomechanical cavity asymmetrically driven around both mechanical sidebands. While, in general, this amplifier is phase-mixing, for a suitable choice of parameters, the amplifier proposed here operates as a phase-sensitive amplifier. We show that both configurations allow amplification with an added noise below the quantum limit of (phase-insensitive) amplification in a parameter range compatible with current experiments in microwave circuit optomechanics. In particular, we show that introducing phase-mixing amplification typically allows for a significant reduction of the added noise.

  6. Targeting MET Amplification as a New Oncogenic Driver

    Directory of Open Access Journals (Sweden)

    Hisato Kawakami

    2014-07-01

    Full Text Available Certain genetically defined cancers are dependent on a single overactive oncogene for their proliferation and survival, a phenomenon known as “oncogene addiction”. A new generation of drugs that selectively target such “driver oncogenes” manifests a clinical efficacy greater than that of conventional chemotherapy in appropriate genetically defined patients. MET is a proto-oncogene that encodes a receptor tyrosine kinase, and aberrant activation of MET signaling occurs in a subset of advanced cancers as result of various genetic alterations including gene amplification, polysomy, and gene mutation. Our preclinical studies have shown that inhibition of MET signaling either with the small-molecule MET inhibitor crizotinib or by RNA interference targeted to MET mRNA resulted in marked antitumor effects in cancer cell lines with MET amplification both in vitro and in vivo. Furthermore, patients with non-small cell lung cancer or gastric cancer positive for MET amplification have shown a pronounced clinical response to crizotinib. Accumulating preclinical and clinical evidence thus suggests that MET amplification is an “oncogenic driver” and therefore a valid target for treatment. However, the prevalence of MET amplification has not been fully determined, possibly in part because of the difficulty in evaluating gene amplification. In this review, we provide a rationale for targeting this genetic alteration in cancer therapy.

  7. Gas Sensor

    KAUST Repository

    Luebke, Ryan

    2015-01-22

    A gas sensor using a metal organic framework material can be fully integrated with related circuitry on a single substrate. In an on-chip application, the gas sensor can result in an area-efficient fully integrated gas sensor solution. In one aspect, a gas sensor can include a first gas sensing region including a first pair of electrodes, and a first gas sensitive material proximate to the first pair of electrodes, wherein the first gas sensitive material includes a first metal organic framework material.

  8. Continuous-flow ATP amplification system for increasing the sensitivity of quantitative bioluminescence assay.

    Science.gov (United States)

    Satoh, Tetsuya; Shinoda, Yasuharu; Alexandrov, Maxym; Kuroda, Akio; Murakami, Yuji

    2008-08-01

    We constructed a novel ATP amplification reactor using a continuous-flow system, and this allowed us to increase the sensitivity of a quantitative bioluminescence assay by controlling the number of ATP amplification cycles. We previously developed a bioluminescence assay coupled with ATP amplification using a batch system. However, it was difficult to control the number of amplification cycles. In this study, ATP amplification was performed using a continuous-flow system, and significant linear correlations between amplified luminescence and initial ATP concentration were observed. When performing four cycles of continuous-flow ATP amplification, the gradient of amplification was 1.87(N). Whereas the lower quantifiable level was 500 pM without amplification, values as low as 50 pM ATP could be measured after amplification. The sensitivity thus increased 10-fold, with further improvements expected with additional amplification cycles. The continuous-flow system thus effectively increased the sensitivity of the quantitative bioluminescence assay.

  9. ASAP: Amplification, sequencing & annotation of plastomes

    Directory of Open Access Journals (Sweden)

    Folta Kevin M

    2005-12-01

    Full Text Available Abstract Background Availability of DNA sequence information is vital for pursuing structural, functional and comparative genomics studies in plastids. Traditionally, the first step in mining the valuable information within a chloroplast genome requires sequencing a chloroplast plasmid library or BAC clones. These activities involve complicated preparatory procedures like chloroplast DNA isolation or identification of the appropriate BAC clones to be sequenced. Rolling circle amplification (RCA is being used currently to amplify the chloroplast genome from purified chloroplast DNA and the resulting products are sheared and cloned prior to sequencing. Herein we present a universal high-throughput, rapid PCR-based technique to amplify, sequence and assemble plastid genome sequence from diverse species in a short time and at reasonable cost from total plant DNA, using the large inverted repeat region from strawberry and peach as proof of concept. The method exploits the highly conserved coding regions or intergenic regions of plastid genes. Using an informatics approach, chloroplast DNA sequence information from 5 available eudicot plastomes was aligned to identify the most conserved regions. Cognate primer pairs were then designed to generate ~1 – 1.2 kb overlapping amplicons from the inverted repeat region in 14 diverse genera. Results 100% coverage of the inverted repeat region was obtained from Arabidopsis, tobacco, orange, strawberry, peach, lettuce, tomato and Amaranthus. Over 80% coverage was obtained from distant species, including Ginkgo, loblolly pine and Equisetum. Sequence from the inverted repeat region of strawberry and peach plastome was obtained, annotated and analyzed. Additionally, a polymorphic region identified from gel electrophoresis was sequenced from tomato and Amaranthus. Sequence analysis revealed large deletions in these species relative to tobacco plastome thus exhibiting the utility of this method for structural and

  10. A continuous-flow ATP amplification system for increasing the sensitivity of quantitative bioluminescence assay

    OpenAIRE

    Satoh, Tetsuya; Shinoda, Yasuharu; Alexandrov, Maxym; Kuroda, Akio; Murakami, Yuji

    2008-01-01

    We constructed a novel ATP amplification reactor using a continuous-flow system, and this allowed us to increase the sensitivity of quantitative bioluminescence assay by controlling the number of ATP amplification cycles. We previously developed a bioluminescence assay coupled with ATP amplification using a batch system. However, it was difficult to control the number of amplification cycles. In this study, ATP amplification was performed using a continuous-flow system, and significant linear...

  11. Regulation of ribosomal DNA amplification by the TOR pathway.

    Science.gov (United States)

    Jack, Carmen V; Cruz, Cristina; Hull, Ryan M; Keller, Markus A; Ralser, Markus; Houseley, Jonathan

    2015-08-01

    Repeated regions are widespread in eukaryotic genomes, and key functional elements such as the ribosomal DNA tend to be formed of high copy repeated sequences organized in tandem arrays. In general, high copy repeats are remarkably stable, but a number of organisms display rapid ribosomal DNA amplification at specific times or under specific conditions. Here we demonstrate that target of rapamycin (TOR) signaling stimulates ribosomal DNA amplification in budding yeast, linking external nutrient availability to ribosomal DNA copy number. We show that ribosomal DNA amplification is regulated by three histone deacetylases: Sir2, Hst3, and Hst4. These enzymes control homologous recombination-dependent and nonhomologous recombination-dependent amplification pathways that act in concert to mediate rapid, directional ribosomal DNA copy number change. Amplification is completely repressed by rapamycin, an inhibitor of the nutrient-responsive TOR pathway; this effect is separable from growth rate and is mediated directly through Sir2, Hst3, and Hst4. Caloric restriction is known to up-regulate expression of nicotinamidase Pnc1, an enzyme that enhances Sir2, Hst3, and Hst4 activity. In contrast, normal glucose concentrations stretch the ribosome synthesis capacity of cells with low ribosomal DNA copy number, and we find that these cells show a previously unrecognized transcriptional response to caloric excess by reducing PNC1 expression. PNC1 down-regulation forms a key element in the control of ribosomal DNA amplification as overexpression of PNC1 substantially reduces ribosomal DNA amplification rate. Our results reveal how a signaling pathway can orchestrate specific genome changes and demonstrate that the copy number of repetitive DNA can be altered to suit environmental conditions.

  12. Strand Invasion Based Amplification (SIBA®): A Novel Isothermal DNA Amplification Technology Demonstrating High Specificity and Sensitivity for a Single Molecule of Target Analyte

    OpenAIRE

    Mark J Hoser; Mansukoski, Hannu K.; Morrical, Scott W.; Kevin E. Eboigbodin

    2014-01-01

    Isothermal nucleic acid amplification technologies offer significant advantages over polymerase chain reaction (PCR) in that they do not require thermal cycling or sophisticated laboratory equipment. However, non-target-dependent amplification has limited the sensitivity of isothermal technologies and complex probes are usually required to distinguish between non-specific and target-dependent amplification. Here, we report a novel isothermal nucleic acid amplification technology, Strand Invas...

  13. FAST MAGNETIC FIELD AMPLIFICATION IN THE EARLY UNIVERSE: GROWTH OF COLLISIONLESS PLASMA INSTABILITIES IN TURBULENT MEDIA

    Energy Technology Data Exchange (ETDEWEB)

    Falceta-Gonçalves, D. [SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS (United Kingdom); Kowal, G. [Escola de Artes, Ciências e Humanidades, Universidade de São Paulo, Rua Arlindo Bettio, 1000, São Paulo, SP 03828-000 (Brazil)

    2015-07-20

    In this work we report on a numerical study of the cosmic magnetic field amplification due to collisionless plasma instabilities. The collisionless magnetohydrodynamic equations derived account for the pressure anisotropy that leads, in specific conditions, to the firehose and mirror instabilities. We study the time evolution of seed fields in turbulence under the influence of such instabilities. An approximate analytical time evolution of the magnetic field is provided. The numerical simulations and the analytical predictions are compared. We found that (i) amplification of the magnetic field was efficient in firehose-unstable turbulent regimes, but not in the mirror-unstable models; (ii) the growth rate of the magnetic energy density is much faster than the turbulent dynamo; and (iii) the efficient amplification occurs at small scales. The analytical prediction for the correlation between the growth timescales and pressure anisotropy is confirmed by the numerical simulations. These results reinforce the idea that pressure anisotropies—driven naturally in a turbulent collisionless medium, e.g., the intergalactic medium, could efficiently amplify the magnetic field in the early universe (post-recombination era), previous to the collapse of the first large-scale gravitational structures. This mechanism, though fast for the small-scale fields (∼kpc scales), is unable to provide relatively strong magnetic fields at large scales. Other mechanisms that were not accounted for here (e.g., collisional turbulence once instabilities are quenched, velocity shear, or gravitationally induced inflows of gas into galaxies and clusters) could operate afterward to build up large-scale coherent field structures in the long time evolution.

  14. Directional Amplification of Horizontal Motion at Rock Sites

    Science.gov (United States)

    Pischiutta, M.; Cianfarra, P.; Salvini, F.; Rovelli, A.

    2016-12-01

    Directional amplifications of horizontal ground motion along site-dependent azimuths are often unexpectedly found in rocky environments and in stiff-rock conditions. Directional amplification has been studied by several authors at sites with fractured rocks across fault damage zones (e.g. Pischiutta et al., 2013), or close to gravitational instabilities (e.g. Burjanek et al, 2012). In the majority of the cases, a transversal relation between the maximum amplification and the orientation of the predominant fracture field is recognized, interpreted as the effect of the stiffness anisotropy. Cracks in fault damage zones also cause the reduction of rock velocity (especially near-surface Vs). Studies performed on high number of rocky sites revealed that directional amplification effects are much more diffuse than expected. A systematic study involving 258 seismological stations of the Italian Seismic Network points out that 56 of stations (20%) are clearly affected by directional site amplification effects. This station sample was studied by analyzing the surface topography in order to unravel the role of topographic irregularities on ground motion amplifications. Models proposed in literature predict amplification at wavelengths comparable to the mountain width (e.g. Géli et al, 1988) and the scatter of wavefield that is polarized in the direction orthogonal to the relief elongation (e.g. Spudich et al., 1996). Since some bias exists in the objective quantification morphological parameters, we use an original methodology that combines morphometric analysis of digital elevation models and principal component analysis to define the dimension and elongation orientation of pronounced ridges. This study showed that the expected relations between the shape/dimension of relief and ground motion were found only at 5 stations (out of 56) , suggesting a major of local morphology, geological complexities and subsurface properties on directional amplification, consistently with

  15. Optimizing direct amplification of forensic commercial kits for STR determination.

    Science.gov (United States)

    Caputo, M; Bobillo, M C; Sala, A; Corach, D

    2017-04-01

    Direct DNA amplification in forensic genotyping reduces analytical time when large sample sets are being analyzed. The amplification success depends mainly upon two factors: on one hand, the PCR chemistry and, on the other, the type of solid substrate where the samples are deposited. We developed a workflow strategy aiming to optimize times and cost when starting from blood samples spotted onto diverse absorbent substrates. A set of 770 blood samples spotted onto Blood cards, Whatman(®) 3 MM paper, FTA™ Classic cards, and Whatman(®) Grade 1 was analyzed by a unified working strategy including a low-cost pre-treatment, a PCR amplification volume scale-down, and the use of the 3500 Genetic Analyzer as the analytical platform. Samples were analyzed using three different commercial multiplex STR direct amplification kits. The efficiency of the strategy was evidenced by a higher percentage of high-quality profiles obtained (over 94%), a reduced number of re-injections (average 3.2%), and a reduced amplification failure rate (lower than 5%). Average peak height ratio among different commercial kits was 0.91, and the intra-locus balance showed values ranging from 0.92 to 0.94. A comparison with previously reported results was performed demonstrating the efficiency of the proposed modifications. The protocol described herein showed high performance, producing optimal quality profiles, and being both time and cost effective. Copyright © 2017 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  16. Adaptive base-isolation of civil structures using variable amplification

    Institute of Scientific and Technical Information of China (English)

    Kenneth K. Walsh; Makola M. Abdullah

    2006-01-01

    Semi-active dampers are used in base-isolation to reduce the seismic response of civil engineering structures.In the present study, a new semi-active damping system using variable amplification will be investigated for adaptive baseisolation. It uses a novel variable amplification device (VAD) connected in series with a passive damper. The VAD is capable of producing multiple amplification factors, each corresponding to a different amplification state. Forces from the damper are amplified to the structure according to the current amplification state, which is selected via a semi-active control algorithm specifically tailored to the system's unique damping characteristics. To demonstrate the effectiveness of the VAD-damper system for adaptive base-isolation, numerical simulations are conducted for three and seven-story base-isolated buildings subject to both far and near-field ground motions. The results indicate that the system can achieve significant reductions in response compared to the base-isolated buildings with no damper. The proposed system is also found to perform well compared to a typical semi-active damper.

  17. Evaluating the displacement amplification factors of concentrically braced steel frames

    Science.gov (United States)

    Mahmoudi, Mussa; Zaree, Mahdi

    2013-12-01

    According to seismic design codes, nonlinear performance of structures is considered during strong earthquakes. Seismic design provisions estimate the maximum roof and story drifts occurring during major earthquakes by amplifying the drifts computed from elastic analysis at the prescribed seismic force level with a displacement amplification factor. The present study tries to evaluate the displacement amplification factors of conventional concentric braced frames (CBFs) and buckling restrained braced frames (BRBFs). As such, static nonlinear (pushover) analysis and nonlinear dynamic time history analysis have been performed on the model buildings with single and double bracing bays, and different stories and brace configurations (chevron V, invert V, and X bracing). It is observed that the displacement amplification factors for BRBFs are higher than that of CBFs. Also, the number of bracing bays and height of buildings have a profound effect on the displacement amplification factors. The evaluated ratios between displacement amplification factors and response modification factors are from 1 to 1.12 for CBFs and from 1 to 1.4 for BRBFs.

  18. Local seismic site amplification: effects of obliquely incident antiplane motions

    Science.gov (United States)

    Cherid, D.; Hammoutene, M.; Tiliouine, B.; Berrah, M. K.

    2016-11-01

    Seismic site amplification studies are generally used to assess the effects of local geology and soil conditions on ground motion characteristics. Although extensive reviews on site amplification phenomena associated with stratigraphic effects can be found in the specialized literature, it should be pointed out that most of the practical applications have been limited to the study of vertically propagating shear horizontal (SH) waves, i.e., to the 1-D soil amplification problem. Furthermore, little attention, if any, has been devoted to the study of the effects of non-vertically incident SH waves on surface accelerograms and on the earthquake response of structures. In the present work, the study is extended to an investigation of 2-D site amplification of non-vertically propagating seismic shear waves in multilayered viscoelastic soil deposits. Sensitivity analyses of the effects of non-vertical incidence on site amplification functions are performed based on site geotechnical data collected from post-seismic investigations of the 1980 El-Asnam earthquake. Analytical results are discussed in terms of seismic site transfer functions, spectral ratios, surface acceleration time histories, and structural response spectra for different values of wave incidence angle. Both bedrock and rock outcropping cases are examined.

  19. Magnetic Amplification by Magnetized Cosmic Rays in SNR Shocks

    CERN Document Server

    Riquelme, Mario A

    2009-01-01

    (Abridged) X-ray observations of synchrotron rims in supernova remnant (SNR) shocks show evidence of strong magnetic field amplification (a factor of ~100 between the upstream and downstream medium). This amplification may be due to plasma instabilities driven by shock-accelerated cosmic rays (CRs). One candidate is the cosmic ray current-driven (CRCD) instability (Bell 2004), caused by the electric current of large Larmor radii CRs propagating parallel to the upstream magnetic field. Particle-in-cell (PIC) simulations have shown that the back-reaction of the amplified field on CRs would limit the amplification factor of this instability to less than ~10 in galactic SNRs. In this paper, we study the possibility of further amplification driven near shocks by "magnetized" CRs, whose Larmor radii are smaller than the length scale of the field that was previously amplified by the CRCD instability. We find that additional amplification can occur due to a new instability, driven by the CR current perpendicular to t...

  20. Amplification of Information by Photons and the Quantum Chernoff Bound

    Science.gov (United States)

    Zwolak, Michael; Riedel, C. Jess; Zurek, Wojciech H.

    2014-03-01

    Amplification was regarded, since the early days of quantum theory, as a mysterious ingredient that endows quantum microstates with macroscopic consequences, key to the ``collapse of the wavepacket,'' and a way to avoid embarrassing problems exemplified by Schrödinger's cat. This bridge between the quantum microworld and the classical world of our experience was postulated ad hoc in the Copenhagen Interpretation. Quantum Darwinism views amplification as replication, in many copies, of information about quantum states. We show that such amplification is a natural consequence of a broad class of models of decoherence, including the photon environment we use to obtain most of our information. The resultant amplification is huge, proportional to # ξQCB . Here, #  is the environment size and ξQCB is the ``typical'' Quantum Chernoff Information, which quantifies the efficiency of the amplification. The information communicated though the environment is imprinted in the states of individual environment subsystems, e.g., in single photons, which document the transfer of information into the environment and result in the emergence of the classical world. See, http://mike.zwolak.org

  1. Processes and impacts of Arctic amplification: A research synthesis

    Science.gov (United States)

    Serreze, Mark C.; Barry, Roger G.

    2011-05-01

    The past decade has seen substantial advances in understanding Arctic amplification — that trends and variability in surface air temperature tend to be larger in the Arctic region than for the Northern Hemisphere or globe as a whole. We provide a synthesis of research on Arctic amplification, starting with a historical context and then addressing recent insights into processes and key impacts, based on analysis of the instrumental record, modeling studies, and paleoclimate reconstructions. Arctic amplification is now recognized as an inherent characteristic of the global climate system, with multiple intertwined causes operating on a spectrum of spatial and temporal scales. These include, but are not limited to, changes in sea ice extent that impact heat fluxes between the ocean and the atmosphere, atmospheric and oceanic heat transports, cloud cover and water vapor that alter the longwave radiation flux to the surface, soot on snow and heightened black carbon aerosol concentrations. Strong warming over the Arctic Ocean during the past decade in autumn and winter, clearly associated with reduced sea ice extent, is but the most recent manifestation of the phenomenon. Indeed, periods of Arctic amplification are evident from analysis of both warm and cool periods over at least the past three million years. Arctic amplification being observed today is expected to become stronger in coming decades, invoking changes in atmospheric circulation, vegetation and the carbon cycle, with impacts both within and beyond the Arctic.

  2. Modeling the amplification dynamics of human Alu retrotransposons.

    Directory of Open Access Journals (Sweden)

    Dale J Hedges

    2005-09-01

    Full Text Available Retrotransposons have had a considerable impact on the overall architecture of the human genome. Currently, there are three lineages of retrotransposons (Alu, L1, and SVA that are believed to be actively replicating in humans. While estimates of their copy number, sequence diversity, and levels of insertion polymorphism can readily be obtained from existing genomic sequence data and population sampling, a detailed understanding of the temporal pattern of retrotransposon amplification remains elusive. Here we pose the question of whether, using genomic sequence and population frequency data from extant taxa, one can adequately reconstruct historical amplification patterns. To this end, we developed a computer simulation that incorporates several known aspects of primate Alu retrotransposon biology and accommodates sampling effects resulting from the methods by which mobile elements are typically discovered and characterized. By modeling a number of amplification scenarios and comparing simulation-generated expectations to empirical data gathered from existing Alu subfamilies, we were able to statistically reject a number of amplification scenarios for individual subfamilies, including that of a rapid expansion or explosion of Alu amplification at the time of human-chimpanzee divergence.

  3. Primer design versus PCR bias in methylation independent PCR amplifications.

    Science.gov (United States)

    Wojdacz, Tomasz K; Borgbo, Tanni; Hansen, Lise Lotte

    2009-05-16

    Many protocols in methylation studies utilize one primer set to generate a PCR product from bisulfite modified template regardless of its methylation status (methylation independent amplification MIP). However, proportional amplification of methylated and unmethylated alleles is hard to achieve due to PCR bias favoring amplification of unmethylated relatively GC poor sequence. Two primer design systems have been proposed to overcome PCR bias in methylation independent amplifications. The first advises against including any CpG dinucleoteides into the primer sequence (CpG-free primers) and the second, recently published by us, is based on inclusion of a limited number of CpG sites into the primer sequence. Here we used the Methylation Sensitive High Resolution Melting (MS-HRM) technology to investigate the ability of primers designed according to both of the above mentioned primer design systems to proportionally amplify methylated and unmethylated templates. Ten "CpG-free" primer pairs and twenty primers containing limited number of CpGs were tested. In reconstruction experiments the "CpG-free" primers showed primer specific sensitivity and allowed us to detect methylation levels in the range from 5 to 50%. Whereas while using primers containing limited number of CpG sites we were able to consistently detect 1-0.1% methylation levels and effectively control PCR amplification bias. In conclusion, the primers with limited number of CpG sites are able to effectively reverse PCR bias and therefore detect methylated templates with significantly higher sensitivity than CpG free primers.

  4. Somatic recombination, gene amplification and cancer.

    Science.gov (United States)

    Ramel, C; Cederberg, H; Magnusson, J; Vogel, E; Natarajan, A T; Mullender, L H; Nivard, J M; Parry, J M; Leyson, A; Comendador, M A; Sierra, L M; Ferreiro, J A; Consuegra, S

    1996-06-12

    The principle objective of this research programme, to analyse chemical induction of somatic recombination and related endpoints, i.e., mobilization of transposing elements and gene amplification, has been approached by means of several assay systems. These have included Drosophila, Saccharomyces and mammalian cell cultures. 6.1. Screening assays for mitotic recombination. A large number of chemicals have been investigated in the three Drosophila assay systems employed--the multiple wing hair/flare wing spot system developed by Graf et al., 1984, the white-ivory system developed by Green et al., 1986 and the white/white+ eye spot assay developed by Vogel (Vogel and Nivard, 1993). Particularly the screening of 181 chemicals, covering a wide array of chemical classes, by the last mentioned assay has shown that measurement of somatic recombination in Drosophila constitutes a sensitive and efficient short-term test which shows a remarkably good correlation with the agent score of 83 short-term tests analysed by ICPEMC (Mendelsohn et al., 1992; Table 2) as well as the assay performance in international collaborative programmes measuring carcinogen/non-carcinogens (de Serres and Ashby, 1981; Ashby et al., 1985, 1988). Also the wing spot assay has gained wide international recognition as a similarly sensitive test. These two assay systems in Drosophila measure both intrachromosomal events and interchromosomal recombination. The white-ivory system on the other hand is based on the loss of a tandem duplication in the white locus, the mechanism of which is less known, but probably involves intrachromosomal recombination. The difference in the mechanism between this assay and the former two was indicated by the lack of response to methotrexate in the white-ivory assay, while this compound was strongly recombinogenic in both the wing spot and white/white+ assays. The use of different strains of Drosophila with the white/white+ assay demonstrated the importance of the

  5. Modeling Loss Amplification After Devastating Disasters

    Science.gov (United States)

    Boissonnade, A. C.; Muir Wood, R.

    2008-05-01

    With the catastrophic events that occurred in 2004 and 2005 came the realization that Catastrophic (Cat) loss models were not properly modeling insured losses and their associated uncertainty. One reason was that major catastrophes were generally characterized by losses caused by the primary initiating events. Such approaches are not adequate when losses can result from the compounded impacts of scenarios of secondary cascading events (physical, economic, social and political) that can have much larger impacts than those due to the primary events themselves. Situations where more and more cascading events can occur will result in different outcomes, some leading to extreme loss events, generally referred as Super Cats. These situations occurred in December 2004 with the Sumatra earthquake and tsunami and in August 2005 with hurricane Katrina and resulting New Orleans flooding. A review of historical events shows that these events are not exceptions. Modeling such scenarios adds new levels of complexity and different perspectives in the understanding of characterizing and assessing impacts of catastrophic events. Modeling economic consequences of extreme events can be improved by developing scenarios of cascades of secondary events triggered by the primary event(s). The likelihood of each scenario should be modeled, along with the hazards of primary and secondary events and resulting losses with their impacts to the different stakeholders. In addition, it is also important to model the impacts of the hazards on the infrastructure and the resulting disruption to the residents and the local economy because these can result in additional losses. This paper describes current work with the goals of better modeling the full economic impacts from catastrophic events, and of a more comprehensive treatment of uncertainty. We will present approaches for modeling loss amplification that account for all the ways in which the cost incurred for a certain level of damage due to a

  6. Turbulent amplification of magnetic fields in laboratory laser-produced shock waves

    Science.gov (United States)

    Meinecke, J.; Doyle, H. W.; Miniati, F.; Bell, A. R.; Bingham, R.; Crowston, R.; Drake, R. P.; Fatenejad, M.; Koenig, M.; Kuramitsu, Y.; C. Kuranz, C.; Lamb, D. Q.; Lee, D.; MacDonald, M. J.; Murphy, C. D.; Park, H.-S.; Pelka, A.; Ravasio, A.; Sakawa, Y.; Schekochihin, A. A.; Scopatz, A.; Tzeferacos, P.; Wan, W. C.; Woolsey, N. C.; Yurchak, R.; Reville, B.; Gregori, G.

    2014-07-01

    X-ray and radio observations of the supernova remnant Cassiopeia A reveal the presence of magnetic fields about 100 times stronger than those in the surrounding interstellar medium. Field coincident with the outer shock probably arises through a nonlinear feedback process involving cosmic rays. The origin of the large magnetic field in the interior of the remnant is less clear but it is presumably stretched and amplified by turbulent motions. Turbulence may be generated by hydrodynamic instability at the contact discontinuity between the supernova ejecta and the circumstellar gas. However, optical observations of Cassiopeia A indicate that the ejecta are interacting with a highly inhomogeneous, dense circumstellar cloud bank formed before the supernova explosion. Here we investigate the possibility that turbulent amplification is induced when the outer shock overtakes dense clumps in the ambient medium. We report laboratory experiments that indicate the magnetic field is amplified when the shock interacts with a plastic grid. We show that our experimental results can explain the observed synchrotron emission in the interior of the remnant. The experiment also provides a laboratory example of magnetic field amplification by turbulence in plasmas, a physical process thought to occur in many astrophysical phenomena.

  7. Lung vasodilatory response to inhaled iloprost in experimental pulmonary hypertension: amplification by different type phosphodiesterase inhibitors

    Directory of Open Access Journals (Sweden)

    Weissmann Norbert

    2005-07-01

    Full Text Available Abstract Inhaled prostanoids and phosphodiesterase (PDE inhibitors have been suggested for treatment of severe pulmonary hypertension. In catheterized rabbits with acute pulmonary hypertension induced by continuous infusion of the stable thromboxane analogue U46619, we asked whether sildenafil (PDE1/5/6 inhibitor, motapizone (PDE3 inhibitor or 8-Methoxymethyl-IBMX (PDE1 inhibitor synergize with inhaled iloprost. Inhalation of iloprost caused a transient pulmonary artery pressure decline, levelling off within per se ineffective dose of each PDE inhibitor (200 μg/kg × min 8-Methoxymethyl-IBMX, 1 μg/kg × min sildenafil, 5 μg/kg × min motapizone with subsequent iloprost nebulization, marked amplification of the prostanoid induced pulmonary vasodilatory response was noted and the area under the curve of PPA reduction was nearly threefold increased with all approaches, as compared to sole iloprost administration. Further amplification was achieved with the combination of inhaled iloprost with sildenafil plus motapizone, but not with sildenafil plus 8MM-IBMX. Systemic hemodynamics and gas exchange were not altered for all combinations. We conclude that co-administration of minute systemic doses of selective PDE inhibitors with inhaled iloprost markedly enhances and prolongs the pulmonary vasodilatory response to inhaled iloprost, with maintenance of pulmonary selectivity and ventilation perfusion matching. The prominent effect of sildenafil may be operative via both PDE1 and PDE5, and is further enhanced by co-application of a PDE3 inhibitor.

  8. Amplification of complex fields in Nd:YAG amplifiers

    Science.gov (United States)

    Chen, Xudong; Chang, Chengcheng; Pu, Jixiong

    2017-04-01

    High energy nanosecond vortex beams and cylindrically polarized beams are generated in Nd:YAG amplifiers. Vortex seed beams and cylindrically polarized seed beams are converted from a conventional Nd:YAG laser by spiral phase plate and polarization converter, respectively. Maximum output energy of optical vortex up to 995 mJ and cylindrically polarized beams up to 772 mJ have been achieved at 10 Hz in a 10-ns pulse, respectively. The amplification efficiency, the beam quality and pulse width of the amplification output are studied. Both the topological charge of the vortex seed beams and polarization state of cylindrically polarized beams are confirmed to be conserved during the amplification. The generation of high energy vortex beams and cylindrically polarized beams would be beneficial to laser material processing.

  9. Linear Amplification of Optical Signal in Coupled Photonic Crystal Waveguides

    CERN Document Server

    Jandieri, Vakhtang

    2015-01-01

    We introduce a weakly coupled photonic crystal waveguide as a promising and realistic model for all-optical amplification. A symmetric pillar type coupled photonic crystal waveguide consisting of dielectric rods periodically distributed in a free space is proposed as all-optical amplifier. Using the unique features of the photonic crystals to control and guide the light, we have properly chosen the frequency at which only one mode (odd mode) becomes the propagating mode in the coupled photonic crystal waveguide, whereas another mode (even mode) is completely reflected from the guiding structure. Under this condition, the all-optical amplification is fully realized. The amplification coefficient for the continuous signal and the Gaussian pulse is calculated.

  10. Measurement-based noiseless linear amplification for quantum communication

    Science.gov (United States)

    Chrzanowski, H. M.; Walk, N.; Haw, J. Y.; Thearle, O.; Assad, S. M.; Janousek, J.; Hosseini, S.; Ralph, T. C.; Symul, T.; Lam, P. K.

    2014-11-01

    Entanglement distillation is an indispensable ingredient in extended quantum communication networks. Distillation protocols are necessarily non-deterministic and require non-trivial experimental techniques such as noiseless amplification. We show that noiseless amplification could be achieved by performing a post-selective filtering of measurement outcomes. We termed this protocol measurement-based noiseless linear amplification (MBNLA). We apply this protocol to entanglement that suffers transmission loss of up to the equivalent of 100km of optical fibre and show that it is capable of distilling entanglement to a level stronger than that achievable by transmitting a maximally entangled state through the same channel. We also provide a proof-of-principle demonstration of secret key extraction from an otherwise insecure regime via MBNLA. Compared to its physical counterpart, MBNLA not only is easier in term of implementation, but also allows one to achieve near optimal probability of success.

  11. Determining Parameters for Images Amplification by Pulses Interpolation

    Directory of Open Access Journals (Sweden)

    Morera-Delfín Leandro

    2015-01-01

    Full Text Available This paper presents the implementation of a method for image samples interpolation based on a physical scanning model. It uses the theory to take digital image samples and to perform an implementation of such mechanism through software. This allows us to get the appropriate parameters for the images amplification using a truncated sampler arrangement. The shown process copies the physical model of image acquisition in order to incorporate the required samples for the amplification. This process is useful in the reconstruction of details in low resolution images and for images compression. The proposed method studies the conservation of high frequency in the high resolution plane for the generation of the amplification kernel. A new way of direct application of the physical model for scanning images in analytic mode is presented.

  12. Current Amplification Characteristics of BJT on Fast Neutron Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Sung Ho; Sun, Gwang Min; Baek, Hani [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    BJT (Bipolar Junction Transistor) is a three-terminal device with an important feature in that the current through two terminals can be controlled by small changes we make in the current or voltage at the third terminal. This control feature allows us to amplify small AC signals or to switch the device from an on state and off state and back. Fast neutron irradiation incurs lattice damage in bulk Si. The recombination rate of minority carriers and register are increased by the lattice damage. This study will investigate the current amplification characteristics of a pnp Si BJT through fast neutron irradiation experiments. In this paper, the current amplification characteristics of a pnp Si BJT were investigated for fast neutron irradiation. The experimental results show that base-tocollector current amplification ratio is decreased with an increase in the fast neutron irradiation. These indicate that the lattice damage caused by fast neutron irradiation increases the recombination rate of minority carriers and resistor.

  13. An Intrinsically Digital Amplification Scheme for Hearing Aids

    Directory of Open Access Journals (Sweden)

    Brenton R. Steele

    2005-11-01

    Full Text Available Results for linear and wide-dynamic range compression were compared with a new 64-channel digital amplification strategy in three separate studies. The new strategy addresses the requirements of the hearing aid user with efficient computations on an open-platform digital signal processor (DSP. The new amplification strategy is not modeled on prior analog strategies like compression and linear amplification, but uses statistical analysis of the signal to optimize the output dynamic range in each frequency band independently. Using the open-platform DSP processor also provided the opportunity for blind trial comparisons of the different processing schemes in BTE and ITE devices of a high commercial standard. The speech perception scores and questionnaire results show that it is possible to provide improved audibility for sound in many narrow frequency bands while simultaneously improving comfort, speech intelligibility in noise, and sound quality.

  14. Identification of genetic elements associated with EPSPs gene amplification.

    Directory of Open Access Journals (Sweden)

    Todd A Gaines

    Full Text Available Weed populations can have high genetic plasticity and rapid responses to environmental selection pressures. For example, 100-fold amplification of the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS gene evolved in the weed species Amaranthus palmeri to confer resistance to glyphosate, the world's most important herbicide. However, the gene amplification mechanism is unknown. We sequenced the EPSPS gene and genomic regions flanking EPSPS loci in A. palmeri, and searched for mobile genetic elements or repetitive sequences. The EPSPS gene was 10,229 bp, containing 8 exons and 7 introns. The gene amplification likely proceeded through a DNA-mediated mechanism, as introns exist in the amplified gene copies and the entire amplified sequence is at least 30 kb in length. Our data support the presence of two EPSPS loci in susceptible (S A. palmeri, and that only one of these was amplified in glyphosate-resistant (R A. palmeri. The EPSPS gene amplification event likely occurred recently, as no sequence polymorphisms were found within introns of amplified EPSPS copies from R individuals. Sequences with homology to miniature inverted-repeat transposable elements (MITEs were identified next to EPSPS gene copies only in R individuals. Additionally, a putative Activator (Ac transposase and a repetitive sequence region were associated with amplified EPSPS genes. The mechanism controlling this DNA-mediated amplification remains unknown. Further investigation is necessary to determine if the gene amplification may have proceeded via DNA transposon-mediated replication, and/or unequal recombination between different genomic regions resulting in replication of the EPSPS gene.

  15. Amplification of maximally-path-entangled number states

    Science.gov (United States)

    Agarwal, G. S.; Chaturvedi, S.; Rai, Amit

    2010-04-01

    We examine the behavior of a non-Gaussian state like the maximally path-entangled number state commonly known as a N00N state under phase-insensitive amplification. We derive an analytical result for the density matrix of the N00N state for arbitrary gain of the amplifier. We consider cases of both symmetric and antisymmetric amplification of the two modes of the N00N state. We quantitatively evaluate the loss of entanglement by the amplifier in terms of the logarithmic negativity parameter. We find that N00N states are more robust than their Gaussian counterparts.

  16. Raman amplification in the broken-wave regime

    CERN Document Server

    Farmer, John P

    2015-01-01

    In regimes far beyond the wavebreaking theshold of Raman amplification, we show that significant amplifcation can occur after the onset of wavebreaking, before phase mixing destroys the coupling between pump and probe. The amplification efficiency in this regime is therefore strongly dependent on the energy-transfer rate when wavebreaking occurs, and is, as such, sensitive to both the probe amplitude and profile. In order to access the higher-efficiency broken-wave regime, a short, intense probe is required. Parameter scans show the marked difference in behaviour compared to below wavebreaking, where longer, more energetic pulses lead to improved efficiencies.

  17. Methods for microbial DNA extraction from soil for PCR amplification

    Directory of Open Access Journals (Sweden)

    Yeates C

    1998-01-01

    Full Text Available Amplification of DNA from soil is often inhibited by co-purified contaminants. A rapid, inexpensive, large-scale DNA extraction method involving minimal purification has been developed that is applicable to various soil types (1. DNA is also suitable for PCR amplification using various DNA targets. DNA was extracted from 100g of soil using direct lysis with glass beads and SDS followed by potassium acetate precipitation, polyethylene glycol precipitation, phenol extraction and isopropanol precipitation. This method was compared to other DNA extraction methods with regard to DNA purity and size.

  18. Wavelength division and subcarrier system based on Brillouin amplification

    Science.gov (United States)

    Lee, Yang-Han; Wu, Jingshown; Kao, Ming-Seng; Tsao, Hen-Wai

    1991-10-01

    This paper analyzes an optical wavelength division multiplexing system (WDM) with subcarrier multiplexing (SCM). The pump laser is tuned to amplify the corresponding optical carrier by fiber Brillouin amplification (FBA) in WDM for the desired group of SCM signals and then a microwave tuner is used to select the desired channel in this group. This system has the benefits of eliminating the need of polarization control, the ability of phase noise cancelling due to the 'squaring' photodetection process of the selected optical carrier together with its SCM channels, and enhancement of optical receiver sensitivities by amplification of the carrier.

  19. Ultra-broad bandwidth parametric amplification at degeneracy.

    Science.gov (United States)

    Limpert, J; Aguergaray, C; Montant, S; Manek-Hönninger, I; Petit, S; Descamps, D; Cormier, E; Salin, F

    2005-09-19

    We report on a novel approach of ultra-broad bandwidth parametric amplification around degeneracy. A bandwidth of up to 400 nm centered around 800 nm is amplified in a BBO crystal by using chirped pump pulses with a bandwitdth as broad as 10 nm. A supercontinuum signal is generated in a microstructured fiber, having to first order a quadratic chirp, which is necessary to ensure temporal overlap of the interacting waves over this broad bandwidth. Furthermore, we discuss the potential of this approach for an octave-spanning parametric amplification.

  20. Exponential quadruplex priming amplification for DNA-based isothermal diagnostics.

    Science.gov (United States)

    Partskhaladze, Tamar; Taylor, Adam; Lomidze, Levan; Gvarjaladze, David; Kankia, Besik

    2015-02-01

    Polymerase chain reaction (PCR) is a method of choice for molecular diagnostics. However, PCR relies on thermal cycling, which is not compatible with the goals of point-of-care diagnostics. A simple strategy to turn PCR into an isothermal method would be to use specific primers, which upon polymerase elongation can self-dissociate from the primer-binding sites. We recently demonstrated that a monomolecular DNA quadruplex, GGGTGGGTGGGTGGG, meets these requirements, which led to the development of the linear versions of quadruplex priming amplification (QPA). Here we demonstrate exponential version of isothermal QPA, which allows an unprecedented 10(10)-fold amplification of DNA signal in less than 40 min.

  1. The emergence of surface-based Arctic amplification

    Directory of Open Access Journals (Sweden)

    M. C. Serreze

    2009-02-01

    Full Text Available Rises in surface and lower troposphere air temperatures through the 21st century are projected to be especially pronounced over the Arctic Ocean during the cold season. This Arctic amplification is largely driven by loss of the sea ice cover, allowing for strong heat transfers from the ocean to the atmosphere. Consistent with observed reductions in sea ice extent, fields from both the NCEP/NCAR and JRA-25 reanalyses point to emergence of surface-based Arctic amplification in the last decade.

  2. Influence of environmental noise on the weak value amplification

    Science.gov (United States)

    Zhu, Xuannmin; Zhang, Yu-Xiang

    2016-08-01

    Quantum systems are always disturbed by environmental noise. We have investigated the influence of the environmental noise on the amplification in weak measurements. Three typical quantum noise processes are discussed in this article. The maximum expectation values of the observables of the measuring device decrease sharply with the strength of the depolarizing and phase damping channels, while the amplification effect of weak measurement is immune to the amplitude damping noise. To obtain significantly amplified signals, we must ensure that the preselection quantum systems are kept away from the depolarizing and phase damping processes.

  3. High-frequency electric field amplification in a magnetized plasma

    Energy Technology Data Exchange (ETDEWEB)

    Timofeev, Aleksandr V [Russian Research Centre ' Kurchatov Institute' , Moscow (Russian Federation)

    2006-11-30

    In the investigation of cyclotron ion heating in systems designed for plasma isotope separation, the high-frequency (HF) electric field amplification effect was found to occur in equilibrium plasma. In the present article this effect is treated as a result of the interaction of the plasma placed in a constant external magnetic field with the HF modes of the vacuum chamber. Consistent elaboration of this approach allowed obtaining a clear interpretation of the HF electric field amplification effect and constructing a simple model of HF field excitation in a plasma column embedded in the external magnetic field. (methodological notes)

  4. Influence of amplification on pulse shaping for coherent control applications

    CSIR Research Space (South Africa)

    Du Plessis, A

    2011-07-01

    Full Text Available of using low seed laser powers for amplification of shaped pulses in a typical setup for coherent control experiments. An acousto-optic programmable dispersive filter (Dazzler from FastLite) is used to shape 130 fs pulses before amplification... measured as such) for low and high seed powers. Clearly, at lower seed powers as in (a), the measured trace corresponds to approximately the 4:1 ratio expected, but at high seed powers this ratio changes towards 2:1, indicating the smaller of the two...

  5. Amplification of Short Pulse High Power UV Laser

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    At recent year, with the development of CPA and other amplification technology, laser intensity achieves great increase and laser power can be high to PW(105) now, this ultrashort pulse lasers offer scientists a route to investigate laser-matter interaction in an absolute new regime.So far the researches on ultrashort pulse laser-matter interaction concentrated on infrared regime, yet ultraviolet laser has the advantage in intense field physics and ICF researches for its short wavelength and less nonlinear effects. KrF excimer is the best medium in UV ultrashort pulse amplification for its small saturation energy and high contrast ratio accessible.

  6. Laser driven X-ray parametric amplification in neutral gases-a new brilliant light source in the XUV

    Energy Technology Data Exchange (ETDEWEB)

    Aurand, B., E-mail: b.aurand@gsi.de [GSI Helmholtz Centre for Heavy Ion Research, Planckstr. 1, 64291 Darmstadt (Germany); ExtreMe Matter Institute, Planckstr. 1, 64291 Darmstadt (Germany); Johannes Gutenberg University Mainz, Saarstr. 21, 55099 Mainz (Germany); Seres, J. [Friedrich-Schiller-University Jena, Max-Wien-Platz 1, 07743 Jena (Germany); Bagnoud, V. [GSI Helmholtz Centre for Heavy Ion Research, Planckstr. 1, 64291 Darmstadt (Germany); Ecker, B. [GSI Helmholtz Centre for Heavy Ion Research, Planckstr. 1, 64291 Darmstadt (Germany); Helmholtz Institut Jena, Helmholtzweg 4, 07743 Jena (Germany); Johannes Gutenberg University Mainz, Saarstr. 21, 55099 Mainz (Germany); Hochhaus, D.C.; Neumayer, P. [GSI Helmholtz Centre for Heavy Ion Research, Planckstr. 1, 64291 Darmstadt (Germany); ExtreMe Matter Institute, Planckstr. 1, 64291 Darmstadt (Germany); Johann-Wolfgang von Goethe University, 60325 Frankfurt (Germany); Seres, E.; Spielmann, C. [Friedrich-Schiller-University Jena, Max-Wien-Platz 1, 07743 Jena (Germany); Zielbauer, B. [GSI Helmholtz Centre for Heavy Ion Research, Planckstr. 1, 64291 Darmstadt (Germany); Helmholtz Institut Jena, Helmholtzweg 4, 07743 Jena (Germany); Zimmer, D. [GSI Helmholtz Centre for Heavy Ion Research, Planckstr. 1, 64291 Darmstadt (Germany); Kuehl, T. [GSI Helmholtz Centre for Heavy Ion Research, Planckstr. 1, 64291 Darmstadt (Germany); ExtreMe Matter Institute, Planckstr. 1, 64291 Darmstadt (Germany); Johannes Gutenberg University Mainz, Saarstr. 21, 55099 Mainz (Germany)

    2011-10-11

    In this paper we present the experimental setup and results showing a new type of strong-field parametric amplification of high-order harmonic radiation. With a simple semi-classical model, we can identify the most important experimental parameters, the spectral range and the small signal gain in gases. Using a single stage amplifier, a small signal gain of 8000 has been obtained in argon for the spectral range of 40-50 eV, using 350 fs, 7 mJ pulses at 1.05 {mu}m. An outlook for an experiment employing a double stage gas system will be given.

  7. Comparison of multiplex ligation dependent probe amplification to immunohistochemistry for assessing HER-2/neu amplification in invasive breast cancer.

    Science.gov (United States)

    Purnomosari, D; Aryandono, T; Setiaji, K; Nugraha, S B; Pals, G; van Diest, P J

    2006-01-01

    The HER-2/neu transmembrane tyrosine kinase receptor is both a prognostic marker and a therapeutic target for breast cancer. Accurate determination of HER-2/neu status is a prerequisite for selecting breast tumors for HER-2/neu immunotherapy or for taxan based chemotherapy. Unfortunately, there is no consensus concerning how this determination should be reached. We compared assessment of HER-2/neu status using Multiplex ligation-dependent probe amplification (MLPA) and immunohistochemistry (IHC). The patient group comprised 60 Indonesian breast cancers patients. IHC was performed on paraffin sections using the CB11 antibody from Novocastra. Results were scored according to the Hercept test. For MLPA, DNA was extracted from frozen samples, PCR amplified with a probe set containing three hemi-primer sets for the HER-2 locus and another nine control probes spread over chromosome 17 and other chromosomes, and analyzed on a gene scanner. A ratio above two for at least two HER-2 locus probes compared to the control probes was regarded as amplification. IHC for HER-2/neu was negative in 36 cases, and 24 cases (40%) showed expression. Seven, eight and nine of the latter cases were 1+, 2+ and 3+ positive, respectively. Forty-seven cases showed no amplification by MLPA, and 13 cases (22%) were amplified. Comparison of IHC and MPLA showed that none of the 36 IHC-negative or seven IHC 1+ cases was amplified. Five of the eight (63%) 2+ cases were amplified, and eight of nine (89%) of the IHC 3+ tumors showed gene amplification by MLPA assay. For HER-2/neu, there is a good correlation between gene amplification detected by MLPA and overexpression by IHC in invasive breast cancer. It appears that MLPA can detect the HER-2 amplified cases in the IHC 2+ class. Because MLPA is quick and inexpensive, it is an attractive method for detecting HER-2/neu amplification in daily laboratory practice.

  8. Highly efficient amplification of chronic wasting disease agent by protein misfolding cyclic amplification with beads (PMCAb.

    Directory of Open Access Journals (Sweden)

    Chad J Johnson

    Full Text Available Protein misfolding cyclic amplification (PMCA has emerged as an important technique for detecting low levels of pathogenic prion protein in biological samples. The method exploits the ability of the pathogenic prion protein to convert the normal prion protein to a proteinase K-resistant conformation. Inclusion of Teflon® beads in the PMCA reaction (PMCAb has been previously shown to increase the sensitivity and robustness of detection for the 263 K and SSLOW strains of hamster-adapted prions. Here, we demonstrate that PMCAb with saponin dramatically increases the sensitivity of detection for chronic wasting disease (CWD agent without compromising the specificity of the assay (i.e., no false positive results. Addition of Teflon® beads increased the robustness of the PMCA reaction, resulting in a decrease in the variability of PMCA results. Three rounds of serial PMCAb allowed detection of CWD agent from a 6.7 × 10(-13 dilution of 10% brain homogenate (1.3 fg of source brain. Titration of the same brain homogenate in transgenic mice expressing cervid prion protein (Tg(CerPrP1536(+/- mice allowed detection of CWD agent from the 10(-6 dilution of 10% brain homogenate. PMCAb is, thus, more sensitive than bioassay in transgenic mice by a factor exceeding 10(5. Additionally, we are able to amplify CWD agent from brain tissue and lymph nodes of CWD-positive white-tailed deer having Prnp alleles associated with reduced disease susceptibility.

  9. Highly efficient amplification of chronic wasting disease agent by protein misfolding cyclical amplification with beads (PMCAb)

    Science.gov (United States)

    Johnson, Chad J.; Aiken, Judd M.; McKenzie, Debbie; Samuel, Michael D.; Pedersen, Joel A.

    2012-01-01

    Protein misfolding cyclic amplification (PMCA) has emerged as an important technique for detecting low levels of pathogenic prion protein in biological samples. The method exploits the ability of the pathogenic prion protein to convert the normal prion protein to a proteinase K-resistant conformation. Inclusion of Teflon® beads in the PMCA reaction (PMCAb) has been previously shown to increase the sensitivity and robustness of detection for the 263 K and SSLOW strains of hamster-adapted prions. Here, we demonstrate that PMCAb with saponin dramatically increases the sensitivity of detection for chronic wasting disease (CWD) agent without compromising the specificity of the assay (i.e., no false positive results). Addition of Teflon® beads increased the robustness of the PMCA reaction, resulting in a decrease in the variability of PMCA results. Three rounds of serial PMCAb allowed detection of CWD agent from a 6.7×10−13 dilution of 10% brain homogenate (1.3 fg of source brain). Titration of the same brain homogenate in transgenic mice expressing cervid prion protein (Tg(CerPrP)1536+/−mice) allowed detection of CWD agent from the 10−6 dilution of 10% brain homogenate. PMCAb is, thus, more sensitive than bioassay in transgenic mice by a factor exceeding 105. Additionally, we are able to amplify CWD agent from brain tissue and lymph nodes of CWD-positive white-tailed deer having Prnp alleles associated with reduced disease susceptibility.

  10. Distinguishing mechanisms of plasma-based amplification for short laser pulses

    Science.gov (United States)

    Jia, Qing; Edwards, Matthew; Barth, Ido; Mikhailova, Julia; Fisch, Nathaniel

    2016-10-01

    Several plasma-based amplification mechanisms have been proposed to obtain short laser pulses with ultrahigh intensities beyond the damage threshold of solid-state devices, including Compton-like superradiant amplification, backward Raman amplification and strongly-coupled Brillouin amplification. These three mechanisms are all based on the periodic structure of particle (electrons for the former two and ions for Brillouin amplification) density fluctuations that function as a grating. By turning off the ion motion in particle-in-cell simulations, we can distinguish Brillouin from Raman, and show that Raman amplification is responsible for the main leading spike amplification of ultrashort pulses. By artificially turning off the longitudinal electric field (Ex) in simulations, we can distinguish Raman from Compton-like superradiant amplification. Interestingly, we find that the superradiant amplification in Ex-off simulation is similar to the amplification in pair plasmas, with roughly half amplification efficiency of the latter due to absence of equal contribution from positrons. In addition, we also discuss the competition between Brillouin amplification and superradiant amplification in pair plasmas by comparing the dominance of thermal pressure and ponderomotive force.

  11. Reversible Gating of Plasmonic Coupling for Optical Signal Amplification.

    Science.gov (United States)

    Khoury, Christopher G; Fales, Andrew M; Vo-Dinh, Tuan

    2016-07-20

    Amplification of optical signals is useful for a wide variety of applications, ranging from data signal transmission to chemical sensing and biomedical diagnostics. One such application in chemical sensing is surface-enhanced Raman scattering (SERS), an important technique for increasing the Raman signal using the plasmonic effect of enhanced electromagnetic fields associated with metallic nanostructures. One of the most important limitations of SERS-based amplification is the difficulty to reproducibly control the SERS signal. Here, we describe the design and implementation of a unique hybrid system capable of producing reversible gating of plasmonic coupling for Raman signal amplification. The hybrid system is composed of two subsystems: (1) colloidal magneto-plasmonic nanoparticles for SERS enhancement and (2) a micromagnet substrate with an externally applied magnetic field to modulate the colloidal nanoparticles. For this proof of concept demonstration, the nanoparticles were labeled with a Raman-active dye, and it was shown that the detected SERS signal could be reproducibly modulated by controlling the externally applied magnetic field. The developed system provides a simple, robust, inexpensive, and reusable device for SERS signal modulation. These properties will open up new possibilities for optical signal amplification and gating as well for high-throughput, reproducible SERS detection.

  12. Factors Affecting the Benefits of High-Frequency Amplification

    Science.gov (United States)

    Horwitz, Amy R.; Ahlstrom, Jayne B.; Dubno, Judy R.

    2008-01-01

    Purpose: This study was designed to determine the extent to which high-frequency amplification helped or hindered speech recognition as a function of hearing loss, gain-frequency response, and background noise. Method: Speech recognition was measured monaurally under headphones for nonsense syllables low-pass filtered in one-third-octave steps…

  13. Controlling the amplification of chirality in hydrogen-bonded assemblies

    NARCIS (Netherlands)

    Mateos-Timoneda, Miguel A.; Crego-Calama, Mercedes; Reinhoudt, David N.

    2005-01-01

    The amplification of chirality (a high enantiomeric or diastereomeric excess induced by a small initial amount of chiral bias) on hydrogen-bonded assemblies has been studied using “sergeants-and-soldiers” experiments under thermodynamically controlled conditions. Here it is shown that different subs

  14. Whole genome amplification and its impact on CGH array profiles

    Directory of Open Access Journals (Sweden)

    Meldrum Cliff

    2008-07-01

    Full Text Available Abstract Background Some array comparative genomic hybridisation (array CGH platforms require a minimum of micrograms of DNA for the generation of reliable and reproducible data. For studies where there are limited amounts of genetic material, whole genome amplification (WGA is an attractive method for generating sufficient quantities of genomic material from miniscule amounts of starting material. A range of WGA methods are available and the multiple displacement amplification (MDA approach has been shown to be highly accurate, although amplification bias has been reported. In the current study, WGA was used to amplify DNA extracted from whole blood. In total, six array CGH experiments were performed to investigate whether the use of whole genome amplified DNA (wgaDNA produces reliable and reproducible results. Four experiments were conducted on amplified DNA compared to unamplified DNA and two experiments on unamplified DNA compared to unamplified DNA. Findings All the experiments involving wgaDNA resulted in a high proportion of losses and gains of genomic material. Previously, amplification bias has been overcome by using amplified DNA in both the test and reference DNA. Our data suggests that this approach may not be effective, as the gains and losses introduced by WGA appears to be random and are not reproducible between different experiments using the same DNA. Conclusion In light of these findings, the use of both amplified test and reference DNA on CGH arrays may not provide an accurate representation of copy number variation in the DNA.

  15. Fiber amplification of radially and azimuthally polarized laser light

    CERN Document Server

    Fridman, Moti; Dubinskiy, Mark; Friesem, Asher A; Davidson, Nir

    2010-01-01

    The results on amplifying either radially or azimuthally polarized light with a fiber amplifier are presented. Experimental results reveal that more than 85% polarization purity can be retained at the output even with 40dB amplification, and that efficient conversion of the amplified light to linear polarization can be obtained.

  16. Static Generalized Brans-Dicke Universe and Gravitational Waves Amplification

    CERN Document Server

    Berman, M S; Berman, Marcelo S.; Trevisan, Luis A.

    2001-01-01

    We find a static solution for the scale-factor in a Brans-Dicke generalized theory where the scalar field and the coupling constant vary with time. We find also that in the early Universe there may be amplification of gravitational waves.

  17. Sexing Bovine Embryos Using PCR Amplification of Bovine SRY Sequence

    Institute of Scientific and Technical Information of China (English)

    曾溢滔; 张美兰; 陈美珏; 周霞娣; 黄英; 任兆瑞; 黄淑帧; 胡明信; 吴学清; 高建明; 张斌; 徐慧如

    1994-01-01

    This study analyses the bovine SRY DNA sequence by direct sequencing procedure, followed by the designation of the PCR primers specific for bovine SRY. Using PCR amplification of bovine SRY gene, the embryo sex was determined. The results of the embryo sex identification were confirmed after the embryo transfer and pregnancies.

  18. Identification and Characterization of Genomic Amplifications in Ovarian Serous Carcinoma

    Science.gov (United States)

    2008-01-01

    targets in the Notch pathway are the Notch receptors, in which ;-secretase inhibitors prevent the generation of the oncogenic (intracellular) domain of...mutations, and chromosomal amplification at the Notch receptor loci, are the known mechanisms for constitutive activation of Notch pathway . Despite the

  19. Parametric amplification in a micro Coriolis mass flow sensor

    NARCIS (Netherlands)

    Groenesteijn, J.; Droogendijk, H.; Wiegerink, R.J.; Lammerink, T.S.J.; Lötters, J.C.; Sanders, R.G.P.; Krijnen, G.J.M.

    2014-01-01

    We report on the application of parametric amplification to a micro Coriolis mass flow sensor. We demonstrate that this mechanism allows for reduction of the system's power dissipation while retaining sensitivity to flow. By reducing this power dissipation, less heat will be transferred to the fluid

  20. Identification of genetic elements associated with EPSPS gene amplification

    Science.gov (United States)

    Weed populations can have high genetic plasticity and rapid responses to environmental selection pressures. For example, 100-fold amplification of the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene evolved to confer resistance to glyphosate, the world's most important herbicide, in the wee...

  1. Macromolecular amplification of binding response in superaptamer hydrogels.

    Science.gov (United States)

    Bai, Wei; Gariano, Nicholas A; Spivak, David A

    2013-05-08

    It is becoming more important to detect ultralow concentrations of analytes for biomedical, environmental, and national security applications. Equally important is that new methods should be easy to use, inexpensive, portable, and if possible allow detection by the naked eye. By and large, detection of low concentrations of analytes cannot be achieved directly but requires signal amplification by catalysts, macromolecules, metal surfaces, or supramolecular aggregates. The rapidly progressing field of macromolecular signal amplification has been advanced using conjugated polymers, chirality in polymers, solvating polymers, and polymerization/depolymerization strategies. A new type of aptamer-based hydrogel with specific response to target proteins presented in this report demonstrates an additional category of macromolecular signal amplification. This superaptamer assembly provides the first example of using protein-specific aptamers to create volume-changing hydrogels with amplified response to the target protein. A remarkable aspect of these superaptamer hydrogels is that volume shrinking is visible to the naked eye down to femtomolar concentrations of protein. This extraordinary macromolecular amplification is attributed to a complex interplay between protein-aptamer supramolecular cross-links and the consequential reduction of excluded volume in the hydrogel. Specific recognition is even maintained in biological matrices such as urine and tears. Furthermore, the gels can be dried for long-term storage and regenerated for use without loss of activity. In practice, the ease of this biomarker detection method offers an alternative to traditional analytical techniques that require sophisticated instrumentation and highly trained personnel.

  2. Direct Extraction and Amplification of DNA from Soil.

    Science.gov (United States)

    Trevors, Jack T.; Leung, K.

    1998-01-01

    Presents an exercise that describes the direct extraction and purification of DNA from a small soil sample. Also discusses the subsequent amplification of a 343-bp Tn7 transposate A gene fragment (tnsA) from a strain of Pseudomonas aureofaciens 3732RNL11. Contains 21 references. (DDR)

  3. Ultrafast double-pulse parametric amplification for precision Ramsey metrology

    NARCIS (Netherlands)

    Kandula, D.Z.; Renault, A.A.L.; Gohle, C.; Wolf, A.L.; Witte, S.; Hogervorst, W.; Ubachs, W.M.G.; Eikema, K.S.E.

    2008-01-01

    We demonstrate phase stable, mJ-level parametric amplification of pulse pairs originating from a Ti: Sapphire frequency comb laser. The amplifier-induced phase shift between the pulses has been determined interferometrically with an accuracy of approximate to 10 mrad. Typical phase shifts are on the

  4. Barcoded Primers Used in Multiplex Amplicon Pyrosequencing Bias Amplification

    OpenAIRE

    2012-01-01

    “Barcode-tagged” PCR primers used for multiplex amplicon sequencing generate a thus-far-overlooked amplification bias that produces variable terminal restriction fragment length polymorphism (T-RFLP) and pyrosequencing data from the same environmental DNA template. We propose a simple two-step PCR approach that increases reproducibility and consistently recovers higher genetic diversity in pyrosequencing libraries.

  5. Loop-mediated isothermal amplification of single pollen grains

    Institute of Scientific and Technical Information of China (English)

    Ali Bektaş; Ignacio Chapela

    2014-01-01

    The polymerase chain reaction (PCR) has been a reliable and fruitful method for many applications in ecology. Nevertheless, unavoidable technical and instrumental require-ments of PCR have limited its widespread application in field situations. The recent development of isothermal DNA amplifica-tion methods provides an alternative to PCR, which circumvents key limitations of PCR for direct amplification in the field. Being able to analyze DNA in the pol en cloud of an ecosystem would provide very useful ecological information, yet would require a field-enabled, high-throughput method for this potential to be realized. Here, we demonstrate the applicability of the loop-mediated DNA amplification method (LAMP), an isothermal DNA amplification technique, to be used in pol en analysis. We demonstrate that LAMP can provide a reliable method to identify species from the pol en cloud, and that it can amplify successful y with sensitivity down to single pol en grains, thus opening the possibility of field-based, high-throughput analysis.

  6. Differential transimpedance amplifier circuit for correlated differential amplification

    Science.gov (United States)

    Gresham, Christopher A.; Denton, M. Bonner; Sperline, Roger P.

    2008-07-22

    A differential transimpedance amplifier circuit for correlated differential amplification. The amplifier circuit increase electronic signal-to-noise ratios in charge detection circuits designed for the detection of very small quantities of electrical charge and/or very weak electromagnetic waves. A differential, integrating capacitive transimpedance amplifier integrated circuit comprising capacitor feedback loops performs time-correlated subtraction of noise.

  7. Four-quadrant flyback converter for direct audio power amplification

    DEFF Research Database (Denmark)

    Ljusev, Petar; Andersen, Michael Andreas E.

    2005-01-01

    This paper presents a bidirectional, four-quadrant flyback converter for use in direct audio power amplification. When compared to the standard Class-D switching audio power amplifier with a separate power supply, the proposed four-quadrant flyback converter provides simple solution with better...

  8. Direct Extraction and Amplification of DNA from Soil.

    Science.gov (United States)

    Trevors, Jack T.; Leung, K.

    1998-01-01

    Presents an exercise that describes the direct extraction and purification of DNA from a small soil sample. Also discusses the subsequent amplification of a 343-bp Tn7 transposate A gene fragment (tnsA) from a strain of Pseudomonas aureofaciens 3732RNL11. Contains 21 references. (DDR)

  9. Observation of non-degenerate photorefractive parametric amplification

    DEFF Research Database (Denmark)

    Pedersen, H.C.; Johansen, P.M.

    1996-01-01

    We report on the first experimental observation of so-called nondegenerate photorefractive parametric amplification. We show that due to this effect it is possible for a weakly modulated photoinduced grating to be parametrically amplified via nonlinear interaction with a strongly modulated...

  10. Soil amplification with a strong impedance contrast: Boston, Massachusetts

    Science.gov (United States)

    Baise, Laurie G.; Kaklamanos, James; Berry, Bradford M; Thompson, Eric

    2016-01-01

    In this study, we evaluate the effect of strong sediment/bedrock impedance contrasts on soil amplification in Boston, Massachusetts, for typical sites along the Charles and Mystic Rivers. These sites can be characterized by artificial fill overlying marine sediments overlying glacial till and bedrock, where the depth to bedrock ranges from 20 to 80 m. The marine sediments generally consist of organic silts, sand, and Boston Blue Clay. We chose these sites because they represent typical foundation conditions in the city of Boston, and the soil conditions are similar to other high impedance contrast environments. The sediment/bedrock interface in this region results in an impedance ratio on the order of ten, which in turn results in a significant amplification of the ground motion. Using stratigraphic information derived from numerous boreholes across the region paired with geologic and geomorphologic constraints, we develop a depth-to-bedrock model for the greater Boston region. Using shear-wave velocity profiles from 30 locations, we develop average velocity profiles for sites mapped as artificial fill, glaciofluvial deposits, and bedrock. By pairing the depth-to-bedrock model with the surficial geology and the average shear-wave velocity profiles, we can predict soil amplification in Boston. We compare linear and equivalent-linear site response predictions for a soil layer of varying thickness over bedrock, and assess the effects of varying the bedrock shear-wave velocity (VSb) and quality factor (Q). In a moderate seismicity region like Boston, many earthquakes will result in ground motions that can be modeled with linear site response methods. We also assess the effect of bedrock depth on soil amplification for a generic soil profile in artificial fill, using both linear and equivalent-linear site response models. Finally, we assess the accuracy of the model results by comparing the predicted (linear site response) and observed site response at the Northeastern

  11. Amplification biases: possible differences among deviating gene expressions

    Directory of Open Access Journals (Sweden)

    Piumi Francois

    2008-01-01

    Full Text Available Abstract Background Gene expression profiling has become a tool of choice to study pathological or developmental questions but in most cases the material is scarce and requires sample amplification. Two main procedures have been used: in vitro transcription (IVT and polymerase chain reaction (PCR, the former known as linear and the latter as exponential. Previous reports identified enzymatic pitfalls in PCR and IVT protocols; however the possible differences between the sequences affected by these amplification defaults were only rarely explored. Results Screening a bovine cDNA array dedicated to embryonic stages with embryonic (n = 3 and somatic tissues (n = 2, we proceeded to moderate amplifications starting from 1 μg of total RNA (global PCR or IVT one round. Whatever the tissue, 16% of the probes were involved in deviating gene expressions due to amplification defaults. These distortions were likely due to the molecular features of the affected sequences (position within a gene, GC content, hairpin number but also to the relative abundance of these transcripts within the tissues. These deviating genes mainly encoded housekeeping genes from physiological or cellular processes (70% and constituted 2 subsets which did not overlap (molecular features, signal intensities, gene ID. However, the differential expressions identified between embryonic stages were both reliable (minor intersect with biased expressions and relevant (biologically validated. In addition, the relative expression levels of those genes were biologically similar between amplified and unamplified samples. Conclusion Conversely to the most recent reports which challenged the use of intense amplification procedures on minute amounts of RNA, we chose moderate PCR and IVT amplifications for our gene profiling study. Conclusively, it appeared that systematic biases arose even with moderate amplification procedures, independently of (i the sample used: brain, ovary or embryos, (ii

  12. Bacteriophage Amplification-Coupled Detection and Identification of Bacterial Pathogens

    Science.gov (United States)

    Cox, Christopher R.; Voorhees, Kent J.

    Current methods of species-specific bacterial detection and identification are complex, time-consuming, and often require expensive specialized equipment and highly trained personnel. Numerous biochemical and genotypic identification methods have been applied to bacterial characterization, but all rely on tedious microbiological culturing practices and/or costly sequencing protocols which render them impractical for deployment as rapid, cost-effective point-of-care or field detection and identification methods. With a view towards addressing these shortcomings, we have exploited the evolutionarily conserved interactions between a bacteriophage (phage) and its bacterial host to develop species-specific detection methods. Phage amplification-coupled matrix assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF-MS) was utilized to rapidly detect phage propagation resulting from species-specific in vitro bacterial infection. This novel signal amplification method allowed for bacterial detection and identification in as little as 2 h, and when combined with disulfide bond reduction methods developed in our laboratory to enhance MALDI-TOF-MS resolution, was observed to lower the limit of detection by several orders of magnitude over conventional spectroscopy and phage typing methods. Phage amplification has been combined with lateral flow immunochromatography (LFI) to develop rapid, easy-to-operate, portable, species-specific point-of-care (POC) detection devices. Prototype LFI detectors have been developed and characterized for Yersinia pestis and Bacillus anthracis, the etiologic agents of plague and anthrax, respectively. Comparable sensitivity and rapidity was observed when phage amplification was adapted to a species-specific handheld LFI detector, thus allowing for rapid, simple, POC bacterial detection and identification while eliminating the need for bacterial culturing or DNA isolation and amplification techniques.

  13. Geometric Effects on the Amplification of First Mode Instability Waves

    Science.gov (United States)

    Kirk, Lindsay C.; Candler, Graham V.

    2013-01-01

    The effects of geometric changes on the amplification of first mode instability waves in an external supersonic boundary layer were investigated using numerical techniques. Boundary layer stability was analyzed at Mach 6 conditions similar to freestream conditions obtained in quiet ground test facilities so that results obtained in this study may be applied to future test article design to measure first mode instability waves. The DAKOTA optimization software package was used to optimize an axisymmetric geometry to maximize the amplification of the waves at first mode frequencies as computed by the 2D STABL hypersonic boundary layer stability analysis tool. First, geometric parameters such as nose radius, cone half angle, vehicle length, and surface curvature were examined separately to determine the individual effects on the first mode amplification. Finally, all geometric parameters were allowed to vary to produce a shape optimized to maximize the amplification of first mode instability waves while minimizing the amplification of second mode instability waves. Since first mode waves are known to be most unstable in the form of oblique wave, the geometries were optimized using a broad range of wave frequencies as well as a wide range of oblique wave angles to determine the geometry that most amplifies the first mode waves. Since first mode waves are seen most often in flows with low Mach numbers at the edge of the boundary layer, the edge Mach number for each geometry was recorded to determine any relationship between edge Mach number and the stability of first mode waves. Results indicate that an axisymmetric cone with a sharp nose and a slight flare at the aft end under the Mach 6 freestream conditions used here will lower the Mach number at the edge of the boundary layer to less than 4, and the corresponding stability analysis showed maximum first mode N factors of 3.

  14. Transcriptome dynamics of transgene amplification in Chinese hamster ovary cells.

    Science.gov (United States)

    Vishwanathan, Nandita; Le, Huong; Jacob, Nitya M; Tsao, Yung-Shyeng; Ng, Sze-Wai; Loo, Bernard; Liu, Zhong; Kantardjieff, Anne; Hu, Wei-Shou

    2014-03-01

    Dihydrofolate reductase (DHFR) system is used to amplify the product gene to multiple copies in Chinese Hamster Ovary (CHO) cells for generating cell lines which produce the recombinant protein at high levels. The physiological changes accompanying the transformation of the non-protein secreting host cells to a high producing cell line is not well characterized. We performed transcriptome analysis on CHO cells undergoing the selection and amplification processes. A host CHO cell line was transfected with a vector containing genes encoding the mouse DHFR (mDHFR) and a recombinant human IgG (hIgG). Clones were isolated following selection and subcloned following amplification. Control cells were transfected with a control plasmid which did not have the hIgG genes. Although methotrexate (MTX) amplification increased the transcript level of the mDHFR gene significantly, its effect on both hIgG heavy and light chain genes was more modest. The subclones appeared to retain the transcriptome signatures of their parental clones, however, their productivity varied among those derived from the same clone. The transcript levels of hIgG transgenes of all subclones fall in a narrower range than the product titer, alluding to the role of many functional attributes, other than transgene transcript, on productivity. We cross examined functional class enrichment during selection and amplification as well as between high and low producers and discerned common features among them. We hypothesize that the role of amplification is not merely increasing transcript levels, but also enriching survivors which have developed the cellular machinery for secreting proteins, leading to an increased frequency of isolating high-producing clones. We put forward the possibility of assembling a hyper-productivity gene set through comparative transcriptome analysis of a wide range of samples.

  15. New perspectives on microbial community distortion after whole-genome amplification

    Science.gov (United States)

    Whole-genome amplification (WGA) has become an important tool to explore the genomic information of microorganisms in an environmental sample with limited biomass, however potential selective biases during the amplification processes are poorly understood. Here, we describe the e...

  16. Systematic evaluation of bias in microbial community profiles induced by whole genome amplification

    NARCIS (Netherlands)

    Direito, S.O.L.; Zaura, E.; Little, M.; Ehrenfreund, P.; Röling, W.F.M.

    2014-01-01

    Whole genome amplification methods facilitate the detection and characterization of microbial communities in low biomass environments. We examined the extent to which the actual community structure is reliably revealed and factors contributing to bias. One widely used [multiple displacement amplific

  17. Rapid isothermal detection of Phytophthora species on plant samples using recombinase polymerase amplification

    Science.gov (United States)

    Recently several isothermal amplification techniques have been developed that are extremely tolerant towards inhibitors present in many plant extracts. Recombinase polymerase amplification (RPA) assays for the genus Phytophthora have been developed which provide a simple and rapid method to macerate...

  18. Requirements for gas quality and gas appliances

    NARCIS (Netherlands)

    Levinsky, Howard; Gersen, Sander; Kiewiet, Bert

    2015-01-01

    Introduction The gas transmission network in the Netherlands transports two different qualities of gas, low-calorific gas known as G-gas or L-gas and, high calorific gas (H-gas). These two gas qualities are transported in separate networks, and are connected by means of five blending and conversion

  19. Gas magnetometer

    Science.gov (United States)

    Walker, Thad Gilbert; Lancor, Brian Robert; Wyllie, Robert

    2016-05-03

    Measurement of a precessional rate of a gas, such as an alkali gas, in a magnetic field is made by promoting a non-uniform precession of the gas in which substantially no net magnetic field affects the gas during a majority of the precession cycle. This allows sensitive gases that would be subject to spin-exchange collision de-phasing to be effectively used for extremely sensitive measurements in the presence of an environmental magnetic field such as the Earth's magnetic field.

  20. Gas magnetometer

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Thad Gilbert; Lancor, Brian Robert; Wyllie, Robert

    2016-05-03

    Measurement of a precessional rate of a gas, such as an alkali gas, in a magnetic field is made by promoting a non-uniform precession of the gas in which substantially no net magnetic field affects the gas during a majority of the precession cycle. This allows sensitive gases that would be subject to spin-exchange collision de-phasing to be effectively used for extremely sensitive measurements in the presence of an environmental magnetic field such as the Earth's magnetic field.

  1. Gas chromatography

    Science.gov (United States)

    Guiochon, Georges; Guillemin, Claude L.

    1990-11-01

    Gas chromatography is a powerful separation technique for gas and vapor mixtures. Combining separation and on-line detection permits accurate quantitative analysis of complex mixtures, including traces of compounds down to parts per trillions in some particular cases. The importance of gas chromatography in quality control and process control in the chemical and drug industry, in environmental pollution investigations and in clinical analysis is critical. The principles of the technique are discussed, the main components of a gas chromatograph are described and some idea of the importance of the applications is given.

  2. Fiber-Optical Parametric Amplification of Sub-Picosecond Pulses for High-Speed Optical Communications

    DEFF Research Database (Denmark)

    Lali-Dastjerdi, Zohreh; Cristofori, Valentina; Rottwitt, Karsten

    2015-01-01

    This article reviews recent results of amplification of short optical pulses using fiber-optical parametric amplifiers. This includes chirped-pulse amplification of 400 fs pulses, error-free amplification of a 640-Gbit/s optical time-division multiplexed signal with less than a 1-dB power penalty...

  3. DC-driven thermoelectric Peltier device for precise DNA amplification

    Science.gov (United States)

    Yamaguchi, Shigeo; Suzuki, Tadzunu; Inoue, Kazuhito; Azumi, Yoshitaka

    2015-05-01

    Using a DC-driven Peltier device, we fabricated a DNA amplification system [polymerase chain reaction (PCR) system] with the aim of increasing its speed and precision. The Peltier device had a well block sandwiched by Bi2Se0.37Te2.36 as an N-type thermoelectric material and Bi0.59Sb1.30Te3 as a P-type material. The well block was directly controlled by the electric current, leading to a high thermal response. Using the Peltier device with the well block, we performed thermal cycles of a PCR, and we demonstrated that our PCR system produces a smaller amount of nonspecific products for the genome DNA (gDNA) of Arabidopsis thaliana, leading to a more precise DNA amplification system.

  4. Soliton-induced relativistic-scattering and amplification

    CERN Document Server

    Rubino, E; Belgiorno, F; Cacciatori, S L; Couairon, A; Leonhardt, U; Faccio, D

    2012-01-01

    Solitons are of fundamental importance in photonics due to applications in optical data transmission and also as a tool for investigating novel phenomena ranging from light generation at new frequencies and wave-trapping to rogue waves. Solitons are also relativistic scatterers: they generate refractive-index perturbations moving at the speed of light. Here we found that such perturbations scatter light in an unusual way: they amplify light by the mixing of positive and negative frequencies, as we describe using a first Born approximation and numerical simulations. The simplest scenario in which these effects may be observed is within the initial stages of optical soliton propagation: a steep shock front develops that may efficiently scatter a second, weaker probe pulse into relatively intense positive and negative frequency modes with amplification at the expense of the soliton. Our results show a novel all-optical amplification scheme that relies on relativistic scattering.

  5. Quantum Privacy Amplification for a Sequence of Single Qubits

    Institute of Scientific and Technical Information of China (English)

    DENG Fu-Guo; LONG Gui-Lu

    2006-01-01

    We present a scheme for quantum privacy amplification (QPA) for a sequence of single qubits. The QPA procedure uses a unitary operation with two controlled-not gates and a Hadamard gate. Every two qubits are performed with the unitary gate operation, and a measurement is made on one photon and the other one is retained.The retained qubit carries the state information of the discarded one. In this way, the information leakage is reduced.The procedure can be performed repeatedly so that the information leakage is reduced to any arbitrarily low level. With this QPA scheme, the quantum secure direct communication with single qubits can be implemented with arbitrarily high security. We also exploit this scheme to do privacy amplification on the single qubits in quantum information sharing for long-distance communication with quantum repeaters.

  6. Chirality Amplification in Tactoids of Lyotropic Chromonic Liquid Crystals

    Science.gov (United States)

    Peng, Chenhui; Lavrentovich, Oleg

    2014-03-01

    We demonstrate an effective chirality amplification based on the long-range forces, extending over the scales of tens of micrometers, much larger than the single molecule (nanometer) scale. The mechanism is rooted in the long-range elastic nature of orientational order in lyotropic chromonic liquid crystals (LCLCs) that represent water solutions of achiral disc-like molecules. Minute quantities of chiral molecules such as amino acid L-alanine and limonene added to the droplets of LCLC lead to chiral amplification characterized by an increase of optical activity by a factor of 103 - 104. This effect allows one to discriminate and detect the absolute configuration of chiral molecules in an aqueous system, thus opening new possibilities in biosensing and other biological applications.

  7. An enzymatic signal amplification system for calorimetric studies of cellobiohydrolases

    DEFF Research Database (Denmark)

    Murphy, Leigh; Baumann, Martin Johannes; Borch, Kim

    2010-01-01

    is heat production. This can be converted to the rate of reaction and allows direct and continuous monitoring of the hydrolysis of complex substrates. To overcome the low molar enthalpy of the hydrolysis of the glycosidic bond, which is typically on the order of −2.5 kJ mol−1, an enzymatic signal......The study of cellulolytic enzymes has traditionally been carried out using endpoint measurements by quantitation of reaction products using high-performance liquid chromatography (HPLC) or overall determination of produced reducing ends. To measure catalytic activity, model substrates...... amplification method has been developed to measure even slow hydrolytically active enzymes such as cellobiohydrolases. This method is explained in detail for the amplification of the heat signal by more than 130 times by using glucose oxidase and catalase. The kinetics of this complex coupled reaction system...

  8. Multigene amplification and massively parallel sequencing for cancer mutation discovery

    Science.gov (United States)

    Dahl, Fredrik; Stenberg, Johan; Fredriksson, Simon; Welch, Katrina; Zhang, Michael; Nilsson, Mats; Bicknell, David; Bodmer, Walter F.; Davis, Ronald W.; Ji, Hanlee

    2007-01-01

    We have developed a procedure for massively parallel resequencing of multiple human genes by combining a highly multiplexed and target-specific amplification process with a high-throughput parallel sequencing technology. The amplification process is based on oligonucleotide constructs, called selectors, that guide the circularization of specific DNA target regions. Subsequently, the circularized target sequences are amplified in multiplex and analyzed by using a highly parallel sequencing-by-synthesis technology. As a proof-of-concept study, we demonstrate parallel resequencing of 10 cancer genes covering 177 exons with average sequence coverage per sample of 93%. Seven cancer cell lines and one normal genomic DNA sample were studied with multiple mutations and polymorphisms identified among the 10 genes. Mutations and polymorphisms in the TP53 gene were confirmed by traditional sequencing. PMID:17517648

  9. Whole genome amplification - Review of applications and advances

    Energy Technology Data Exchange (ETDEWEB)

    Hawkins, Trevor L.; Detter, J.C.; Richardson, Paul

    2001-11-15

    The concept of Whole Genome Amplification is something that has arisen in the past few years as modifications to the polymerase chain reaction (PCR) have been adapted to replicate regions of genomes which are of biological interest. The applications here are many--forensics, embryonic disease diagnosis, bio terrorism genome detection, ''imoralization'' of clinical samples, microbial diversity, and genotyping. The key question is if DNA can be replicated a genome at a time without bias or non random distribution of the target. Several papers published in the last year and currently in preparation may lead to the conclusion that whole genome amplification may indeed be possible and therefore open up a new avenue to molecular biology.

  10. Transcriptional Amplification in Tumor Cells with Elevated c-Myc

    Science.gov (United States)

    Lin, Charles Y.; Lovén, Jakob; Rahl, Peter B.; Paranal, Ronald M.; Burge, Christopher B.; Bradner, James E.; Lee, Tong Ihn; Young, Richard A.

    2012-01-01

    Summary Elevated expression of the c-Myc transcription factor occurs frequently in human cancers and is associated with tumor aggression and poor clinical outcome. The effect of high levels of c-Myc on global gene regulation is poorly understood, but is widely thought to involve newly activated or repressed “Myc target genes”. We report here that in tumor cells expressing high levels of c-Myc, the transcription factor accumulates in the promoter regions of active genes and causes transcriptional amplification, producing increased levels of transcripts within the cell's gene expression program. Thus, rather than binding and regulating a new set of genes, c-Myc amplifies the output of the existing gene expression program. These results provide an explanation for the diverse effects of oncogenic c-Myc on gene expression in different tumor cells and suggest that transcriptional amplification reduces rate-limiting constraints for tumor cell growth and proliferation. PMID:23021215

  11. Amplification, Decoherence, and the Acquisition of Information by Spin Environments

    Science.gov (United States)

    Zwolak, Michael; Riedel, C. Jess; Zurek, Wojciech H.

    2016-05-01

    Quantum Darwinism recognizes the role of the environment as a communication channel: Decoherence can selectively amplify information about the pointer states of a system of interest (preventing access to complementary information about their superpositions) and can make records of this information accessible to many observers. This redundancy explains the emergence of objective, classical reality in our quantum Universe. Here, we demonstrate that the amplification of information in realistic spin environments can be quantified by the quantum Chernoff information, which characterizes the distinguishability of partial records in individual environment subsystems. We show that, except for a set of initial states of measure zero, the environment always acquires redundant information. Moreover, the Chernoff information captures the rich behavior of amplification in both finite and infinite spin environments, from quadratic growth of the redundancy to oscillatory behavior. These results will considerably simplify experimental testing of quantum Darwinism, e.g., using nitrogen vacancies in diamond.

  12. Parametric Amplification of Vacuum Fluctuations in a Spinor Condensate

    DEFF Research Database (Denmark)

    Klempt, C.; Topic, O.; Gebreyesus, G.

    2010-01-01

    Parametric amplification of vacuum fluctuations is crucial in modern quantum optics, enabling the creation of squeezing and entanglement. We demonstrate the parametric amplification of vacuum fluctuations for matter waves using a spinor F=2 87Rb condensate. Interatomic interactions lead...... to correlated pair creation in the mF=±1 states from an initial mF=0 condensate, which acts as a vacuum for mF≠0. Although this pair creation from a pure mF=0 condensate is ideally triggered by vacuum fluctuations, unavoidable spurious initial mF=±1 atoms induce a classical seed which may become the dominant...... triggering mechanism. We show that pair creation is insensitive to a classical seed for sufficiently large magnetic fields, demonstrating the dominant role of vacuum fluctuations. The presented system thus provides a direct path towards the generation of nonclassical states of matter....

  13. Divided-pulse nonlinear amplification and simultaneous compression

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Qiang; Zhang, Qingshan; Sun, Tingting; Chen, Jie; Wang, Yuqing; Guo, Zhengru; Yang, Kangwen [Shanghai Key Laboratory of Modern Optical System, and Engineering Research Center of Optical Instrument and System, Ministry of Education, School of Optical Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093 (China); Guo, Zhanhua [Shanghai Langyan Optoelectronic Science and Technology Co., LTD, Shanghai 200433 (China); Zeng, Heping, E-mail: hpzeng@phy.ecnu.edu.cn [Shanghai Key Laboratory of Modern Optical System, and Engineering Research Center of Optical Instrument and System, Ministry of Education, School of Optical Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093 (China); State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062 (China)

    2015-03-09

    We report on a fiber laser system delivering 122 fs pulse duration and 600 mW average power at 1560 nm by the interplay between divided pulse amplification and nonlinear pulse compression. A small-core double-clad erbium-doped fiber with anomalous dispersion carries out the pulse amplification and simultaneously compresses the laser pulses such that a separate compressor is no longer necessary. A numeric simulation reveals the existence of an optimum fiber length for producing transform-limited pulses. Furthermore, frequency doubling to 780 nm with 240 mW average power and 98 fs pulse duration is achieved by using a periodically poled lithium niobate crystal at room temperature.

  14. Surface plasmon polariton amplification in semiconductor-graphene-dielectric structure

    Energy Technology Data Exchange (ETDEWEB)

    Dadoenkova, Yuliya S. [Ulyanovsk State University, Ulyanovsk (Russian Federation); Novgorod State University, Veliky Novgorod (Russian Federation); Donetsk Institute for Physics and Technology, Donetsk (Ukraine); Moiseev, Sergey G. [Ulyanovsk State University, Ulyanovsk (Russian Federation); Kotelnikov Institute of Radio Engineering and Electronics, Russian Academy of Sciences, Ulyanovsk (Russian Federation); Abramov, Aleksei S. [Ulyanovsk State University, Ulyanovsk (Russian Federation); Kadochkin, Aleksei S.; Zolotovskii, Igor O. [Ulyanovsk State University, Ulyanovsk (Russian Federation); Institute of Nanotechnologies of Microelectronics of the Russian Academy of Sciences, 32A Leninskiy Prosp., 119991, Moscow (Russian Federation); Fotiadi, Andrei A. [Ulyanovsk State University, Ulyanovsk (Russian Federation); Universite de Mons (Belgium)

    2017-05-15

    A mechanism of amplification of surface plasmon polaritons due to the transfer of electromagnetic energy from a drift current wave into a far-infrared surface wave propagating along a semiconductor-dielectric boundary in waveguide geometry is proposed. A necessary condition of the interaction of these waves is phase matching condition, i. e., when the phase velocity of the surface wave approaches the drift velocity of charge carriers. It is shown that in the spectral region of the surface plasmon polariton slowing-down its amplification coefficient can reach values substantially exceeding the ohmic loss coefficient of the surface wave in the structure. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Assessing Linearity of the Parasite Varroa destructor DNA Amplification

    Directory of Open Access Journals (Sweden)

    ODAGIU Antonia

    2009-12-01

    Full Text Available The importance of honeybee products make of disease prevention and control in honeybees one of the mainconcerns of beekeepers in the world. The PCR – RT reaction represents an alternative for amplification performed inorder to realize the Varroa destructor O. genotypization, very important stage in haoneybee resistance to parasitedescription and also in management of the treatments. The linearity data is a very important parameter and very usefulin determination of the amplification of the parasite DNA and success of the genotypization process. The amplificationefficiency was very satisfactory, fact revealed by the value of the regression line y = - 2.3103 * 26.552 together withcoefficient of determination equal (r2 = 0.9691, meaning that more than 96% of the reaction efficiency may beexplained by the process liniarity. The implementation of the RT-PCR method was successful and it represents apremise for validation process evolution.

  16. Rolling circle amplification of complete nematode mitochondrial genomes.

    Science.gov (United States)

    Tang, Sha; Hyman, Bradley C

    2005-06-01

    To enable investigation of nematode mitochondrial DNA evolution, methodology has been developed to amplify intact nematode mitochondrial genomes in preparative yields using a rolling circle replication strategy. Successful reactions were generated from whole cell template DNA prepared by alkaline lysis of the rhabditid nematode Caenorhabditis elegans and a mermithid nematode, Thaumamermis cosgrovei. These taxa, representing the two major nematode classes Chromodorea and Enoplea, maintain mitochondrial genomes of 13.8 kb and 20.0 kb, respectively. Efficient amplifications were conducted on template DNA isolated from individual or pooled nematodes that were alive or stored at -80 degrees C. Unexpectedly, these experiments revealed that multiple T. cosgrovei mitochondrial DNA haplotypes are maintained in our local population. Rolling circle amplification products can be used as templates for standard PCR reactions with specific primers that target mitochondrial genes or for direct DNA sequencing.

  17. Rapid amplification of cDNA ends (RACE).

    Science.gov (United States)

    Yeku, Oladapo; Frohman, Michael A

    2011-01-01

    Rapid Amplification of cDNA ends (RACE) provides an inexpensive and powerful tool to quickly obtain full-length cDNA when the sequence is only partially known. Starting with an mRNA mixture, gene-specific primers generated from the known regions of the gene and non-specific anchors, full-length sequences can be identified in as little as 3 days. RACE can also be used to identify alternative transcripts of a gene when the partial or complete sequence of only one transcript is known. In the following sections, we outline details for rapid amplification of 5(') and 3(') cDNA ends using the "new RACE" technique.

  18. Weak value amplification is suboptimal for estimation and detection.

    Science.gov (United States)

    Ferrie, Christopher; Combes, Joshua

    2014-01-31

    We show by using statistically rigorous arguments that the technique of weak value amplification does not perform better than standard statistical techniques for the tasks of single parameter estimation and signal detection. Specifically, we prove that postselection, a necessary ingredient for weak value amplification, decreases estimation accuracy and, moreover, arranging for anomalously large weak values is a suboptimal strategy. In doing so, we explicitly provide the optimal estimator, which in turn allows us to identify the optimal experimental arrangement to be the one in which all outcomes have equal weak values (all as small as possible) and the initial state of the meter is the maximal eigenvalue of the square of the system observable. Finally, we give precise quantitative conditions for when weak measurement (measurements without postselection or anomalously large weak values) can mitigate the effect of uncharacterized technical noise in estimation.

  19. Retrieval and Amplification of DNA from Unstained Histopathological Sections

    Institute of Scientific and Technical Information of China (English)

    DonnaC.MONTAGUE; BeverlyD.LYN-COOK; 等

    1993-01-01

    Testing of compounds for carcinogenic potential in vivo involves various experimental designs.A few of these techniques are directed to demonstrate the genotoxicity and mutagenicity of the compound by histopathology.These changes shown by histochemical means include monoclonal antibody directed cellular markers.Development of the polymerase chain reaction technique(PCR)for amplification of DNA has facilitated the investigation of molecular events related to the formation of malignant neoplasms.We describe here a method for screening tissues for mutations of the H-ras gene using monoclonal antibodies directed toward normal and mutant p21 proteins.Formalin-fixed,paraffinembedded tissue sections are used to subsequently confirm the gene mutation by PCR amplification of the H-ras gene.The results indicated a successful application of this technique to demonstrate the presence of p21 oncoprotein in the tissues tested.

  20. Resonant Amplification of Turbulence by the Blast Wawes

    CERN Document Server

    Zankovich, A M

    2016-01-01

    We discuss an idea whether spherical blast waves can amplify by a non-local resonant hydrodynamic mechanism inhomogeneities formed by turbulence or phase segregation in the interstellar medium. We consider the problem of a blast-wave-turbulence interaction in the Linear Interaction Approximation. Mathematically, this is an eigenvalue problem for finding the structure and amplitude of eigenfunctions describing the response of the shock-wave flow to forced oscillations by external perturbations in the ambient interstellar medium. Linear analysis shows that the blast wave can amplify density and vorticity perturbations for a wide range of length scales with amplification coefficients of up to 20, with amplification the greater, the larger the length. There also exist resonant harmonics for which the gain becomes formally infinite in the linear approximation. Their orbital wavenumbers are within the range of macro- ($l \\sim 1$), meso- ($l \\sim 20$) and microscopic ($l > 200$) scales. Since the resonance width is ...

  1. Integrated Microfluidic Nucleic Acid Isolation, Isothermal Amplification, and Amplicon Quantification

    OpenAIRE

    Mauk, Michael G.; Changchun Liu; Jinzhao Song; Bau, Haim H.

    2015-01-01

    Microfluidic components and systems for rapid (<60 min), low-cost, convenient, field-deployable sequence-specific nucleic acid-based amplification tests (NAATs) are described. A microfluidic point-of-care (POC) diagnostics test to quantify HIV viral load from blood samples serves as a representative and instructive example to discuss the technical issues and capabilities of “lab on a chip” NAAT devices. A portable, miniaturized POC NAAT with performance comparable to conventional PCR (poly...

  2. Purely nonlinear disorder-induced localizations and their parametric amplification

    CERN Document Server

    Folli, Viola; Conti, Claudio

    2013-01-01

    We investigate spatial localization in a quadratic nonlinear medium in the presence of randomness. By means of numerical simulations and theoretical analyses we show that, in the down conversion regime, the transverse random modulation of the nonlinear susceptibility generates localizations of the fundamental wave that grow exponentially in propagation. The localization length is optically controlled by the pump intensity which determines the amplification rate. The results also apply to cubic nonlinearities.

  3. Hyper dispersion pulse compressor for chirped pulse amplification systems

    Science.gov (United States)

    Barty, Christopher P. J.

    2011-11-29

    A grating pulse compressor configuration is introduced for increasing the optical dispersion for a given footprint and to make practical the application for chirped pulse amplification (CPA) to quasi-narrow bandwidth materials, such as Nd:YAG. The grating configurations often use cascaded pairs of gratings to increase angular dispersion an order of magnitude or more. Increased angular dispersion allows for decreased grating separation and a smaller compressor footprint.

  4. Adiabatic Amplification of Plasmons and Demons in 2D Systems.

    Science.gov (United States)

    Sun, Zhiyuan; Basov, D N; Fogler, M M

    2016-08-12

    We theoretically investigate charged collective modes in a two-dimensional conductor with hot electrons where the instantaneous mode frequencies gradually increase or decrease with time. We show that the loss compensation or even amplification of the modes may occur. We apply our theory to two types of collective modes in graphene, the plasmons and the energy waves, which can be probed in optical pump-probe experiments.

  5. Phase sensitive amplification in silicon photonic crystal waveguides

    CERN Document Server

    Yanbing,; Husko, Chad; Schroder, Jochen; Lefrancois, Simon; Rey, Isabella H; Krauss, Thomas F; Eggleton, Benjamin J

    2013-01-01

    We experimentally demonstrate phase sensitive amplification (PSA) in a silicon photonic crystal waveguide based on pump-degenerate four-wave mixing. An 11 dB phase extinction ratio is obtained in a record compact 196 {\\mu}m nanophotonic device due to broadband slow-light, in spite of the presence of two-photon absorption and free-carriers. Numerical calculations show good agreement with the experimental results.

  6. Phase-sensitive amplification in silicon photonic crystal waveguides.

    Science.gov (United States)

    Zhang, Yanbing; Husko, Chad; Schröder, Jochen; Lefrancois, Simon; Rey, Isabella H; Krauss, Thomas F; Eggleton, Benjamin J

    2014-01-15

    We experimentally demonstrate phase-sensitive amplification in a silicon photonic crystal waveguide based on pump-degenerate four-wave mixing. An 11 dB phase-extinction ratio is obtained in a record compact 196 μm nanophotonic device due to broadband slow light, in spite of the presence of two-photon absorption and free carriers. Numerical calculations show good agreement with the experimental results.

  7. Complete genome amplification of Equine influenza virus subtype 2

    OpenAIRE

    Sguazza, G. H.; Fuentealba, N. A.; Tizzano, Marco Antonio; Galosi, Cecilia Mónica; Pecoraro, M. R.

    2009-01-01

    This work reports a method for rapid amplification of the complete genome of equine influenza virus subtype 2 (H3N8). A ThermoScriptTM reverse transcriptase instead of the avian myeloblastosis virus reverse transcriptase or Moloney murine leukemia virus reverse transcriptase was used. This enzyme has demonstrated higher thermal stability and is described as suitable to make long cDNA with a complex secondary structure. The product obtained by this method can be cloned, used in later...

  8. Surface plasmon polariton amplification in metal-semiconductor structures.

    Science.gov (United States)

    Fedyanin, Dmitry Yu; Arsenin, Aleksey V

    2011-06-20

    We propose a novel scheme of surface plasmon polariton (SPP) amplification that is based on a minority carrier injection in a Schottky diode. This scheme uses compact electrical pumping instead of bulky optical pumping. Compact size and a planar structure of the proposed amplifier allow one to utilize it in integrated plasmonic circuits and couple it easily to passive plasmonic devices. Moreover, this technique can be used to obtain surface plasmon lasing.

  9. Generation and Amplification of Terahertz Radiation in Carbon Nanotubes

    OpenAIRE

    Abukari, S. S.; Mensah, S. Y.; Mensah, N. G.; Adu, K. W.; Rabiu, M; Dompreh, K. A.; Twum, A.

    2012-01-01

    We investigate theoretically the feasibility of generation and amplification of terahertz radiation in aligned achiral carbon nanotubes (zigzag and armchair) in comparison with a superlattice in the presence of a constant (dc) and high-frequency (ac) electric fields. The electric current density expression is derived using the semiclassical Boltzmann transport equation with a constant relaxation time with the electric field applied along the nanotube axis. Our analysis on the current density ...

  10. Whole genome amplification of DNA for genotyping pharmacogenetics candidate genes.

    Directory of Open Access Journals (Sweden)

    Santosh ePhilips

    2012-03-01

    Full Text Available Whole genome amplification (WGA technologies can be used to amplify genomic DNA when only small amounts of DNA are available. The Multiple Displacement Amplification Phi polymerase based amplification has been shown to accurately amplify DNA for a variety of genotyping assays; however, it has not been tested for genotyping many of the clinically relevant genes important for pharmacogenetic studies, such as the cytochrome P450 genes, that are typically difficult to genotype due to multiple pseudogenes, copy number variations, and high similarity to other related genes. We evaluated whole genome amplified samples for Taqman™ genotyping of SNPs in a variety of pharmacogenetic genes. In 24 DNA samples from the Coriell human diversity panel, the call rates and concordance between amplified (~200-fold amplification and unamplified samples was 100% for two SNPs in CYP2D6 and one in ESR1. In samples from a breast cancer clinical trial (Trial 1, we compared the genotyping results in samples before and after WGA for four SNPs in CYP2D6, one SNP in CYP2C19, one SNP in CYP19A1, two SNPs in ESR1, and two SNPs in ESR2. The concordance rates were all >97%. Finally, we compared the allele frequencies of 143 SNPs determined in Trial 1 (whole genome amplified DNA to the allele frequencies determined in unamplified DNA samples from a separate trial (Trial 2 that enrolled a similar population. The call rates and allele frequencies between the two trials were 98% and 99.7%, respectively. We conclude that the whole genome amplified DNA is suitable for Taqman™ genotyping for a wide variety of pharmacogenetically relevant SNPs.

  11. Metrology with Weak Value Amplification and Related Topics

    Science.gov (United States)

    2013-10-12

    common optical telecom networks. More recently, the amplification properties of this weak value effect have been exploited in similar optical systems to...applications). The light in one port was measured with a photodiode and used to lock the power at 2 mW with an acousto- optic modulator before the fiber ...We examine a sequence of polarized laser pulses effectively trapped inside an interferometer using a Pockels cell and polarization optics . In

  12. Complete genome amplification of Equine influenza virus subtype 2

    OpenAIRE

    Sguazza, G.H.; Fuentealba, N. A.; Tizzano, Marco Antonio; Galosi, Cecilia Mónica; M. R. Pecoraro

    2009-01-01

    This work reports a method for rapid amplification of the complete genome of equine influenza virus subtype 2 (H3N8). A ThermoScriptTM reverse transcriptase instead of the avian myeloblastosis virus reverse transcriptase or Moloney murine leukemia virus reverse transcriptase was used. This enzyme has demonstrated higher thermal stability and is described as suitable to make long cDNA with a complex secondary structure. The product obtained by this method can be cloned, used in later...

  13. Amplification of acoustic waves in laminated piezoelectric semiconductor plates

    Energy Technology Data Exchange (ETDEWEB)

    Yang, J.S.; Yang, X.M.; Turner, J.A. [University of Nebraska, Department of Engineering Mechanics, Lincoln, NE (United States)

    2004-12-01

    Two-dimensional equations for coupled extensional, flexural and thickness-shear motions of laminated plates of piezoelectric semiconductors are obtained systematically from the three-dimensional equations by retaining lower order terms in power series expansions in the plate thickness coordinate. The equations are used to analyze extensional waves in a composite plate of piezoelectric ceramics and semiconductors. Dispersion and dissipation due to semiconduction as well as wave amplification by a dc electric field are discussed. (orig.)

  14. Effect of Arctic Amplification on Design Snow Loads in Alaska

    Science.gov (United States)

    2016-09-01

    Bare 0.01 — 19 Water/possibly frozen 0.01 — 20 Permanent snow/glacier 0.01 — 21 Residential/ urban 0.01 — 22 Tall crops 0.4 — 23 Short crops 0.25...of Arctic Amplification: A Research Synthesis.Global and Planetary Change, 77:85–96. Sturm, M. 2012. Ice-Road Trucker Lessons in How Climate Change

  15. Making an Effort to Listen: Mechanical Amplification in the Ear

    OpenAIRE

    Hudspeth, A. J.

    2008-01-01

    The inner ear’s performance is greatly enhanced by an active process defined by four features: amplification, frequency selectivity, compressive nonlinearity, and spontaneous otoacoustic emission. These characteristics emerge naturally if the mechanoelectrical transduction process operates near a dynamical instability, the Hopf bifurcation, whose mathematical properties account for specific aspects of our hearing. The active process of non-mammalian tetrapods depends upon active hair-bundle m...

  16. Arctic amplification: does it impact the polar jet stream?

    Directory of Open Access Journals (Sweden)

    Valentin P. Meleshko

    2016-10-01

    Full Text Available It has been hypothesised that the Arctic amplification of temperature changes causes a decrease in the northward temperature gradient in the troposphere, thereby enhancing the oscillation of planetary waves leading to extreme weather in mid-latitudes. To test this hypothesis, we study the response of the atmosphere to Arctic amplification for a projected summer sea-ice-free period using an atmospheric model with prescribed surface boundary conditions from a state-of-the-art Earth system model. Besides a standard global warming simulation, we also conducted a sensitivity experiment with sea ice and sea surface temperature anomalies in the Arctic. We show that when global climate warms, enhancement of the northward heat transport provides the major contribution to decrease the northward temperature gradient in the polar troposphere in cold seasons, causing more oscillation of the planetary waves. However, while Arctic amplification significantly enhances near-surface air temperature in the polar region, it is not large enough to invoke an increased oscillation of the planetary waves.

  17. Diagnosis of brugian filariasis by loop-mediated isothermal amplification.

    Directory of Open Access Journals (Sweden)

    Catherine B Poole

    Full Text Available In this study we developed and evaluated a Brugia Hha I repeat loop-mediated isothermal amplification (LAMP assay for the rapid detection of Brugia genomic DNA. Amplification was detected using turbidity or fluorescence as readouts. Reactions generated a turbidity threshold value or a clear visual positive within 30 minutes using purified genomic DNA equivalent to one microfilaria. Similar results were obtained using DNA isolated from blood samples containing B. malayi microfilariae. Amplification was specific to B. malayi and B. timori, as no turbidity was observed using DNA from the related filarial parasites Wuchereria bancrofti, Onchocerca volvulus or Dirofilaria immitis, or from human or mosquito. Furthermore, the assay was most robust using a new strand-displacing DNA polymerase termed Bst 2.0 compared to wild-type Bst DNA polymerase, large fragment. The results indicate that the Brugia Hha I repeat LAMP assay is rapid, sensitive and Brugia-specific with the potential to be developed further as a field tool for diagnosis and mapping of brugian filariasis.

  18. Field and Current Amplification in the SSPX Spheromak

    Energy Technology Data Exchange (ETDEWEB)

    Hill, D N; Blumer, R H; Cohen, B I; Hooper, E B; McLean, H S; Moller, J; Pearlstein, L D; Ryutov, D D; Stallard, B W; Wood, R D; Woodruff, S; Holcomb, C T; Jarboe, T; Bellan, P; Romero-Talamas, C

    2002-10-08

    Results are presented from experiments relating to magnetic field generation and current amplification in the SSPX spheromak. The SSPX spheromak plasma is driven by DC coaxial helicity injection using a 2MJ capacitor bank. Peak toroidal plasma currents of up to 0.7MA and peak edge poloidal fields of 0.3T are produced; lower current discharges can be sustained up to 3.5msec. When edge magnetic fluctuations are reduced below 1% by driving the plasma near threshold, it is possible to produce plasmas with Te > 150eV, <{beta}{sub e}>-4% and core {chi}{sub e} {approx} 30m{sup 2}/s. Helicity balance for these plasmas suggests that sheath dissipation can be significant, pointing to the importance of maximizing the voltage on the coaxial injector. For most operational modes we find a stiff relationship between peak spheromak field and injector current, and little correlation with plasma temperature, which suggests that other processes than ohmic dissipation may limit field amplification. However, slowing spheromak buildup by limiting the initial current pulse increases the ratio of toroidal current to injected current and points to new operating regimes with more favorable current amplification.

  19. Mechanism of seasonal Arctic sea ice evolution and Arctic amplification

    Science.gov (United States)

    Kim, Kwang-Yul; Hamlington, Benjamin D.; Na, Hanna; Kim, Jinju

    2016-09-01

    Sea ice loss is proposed as a primary reason for the Arctic amplification, although the physical mechanism of the Arctic amplification and its connection with sea ice melting is still in debate. In the present study, monthly ERA-Interim reanalysis data are analyzed via cyclostationary empirical orthogonal function analysis to understand the seasonal mechanism of sea ice loss in the Arctic Ocean and the Arctic amplification. While sea ice loss is widespread over much of the perimeter of the Arctic Ocean in summer, sea ice remains thin in winter only in the Barents-Kara seas. Excessive turbulent heat flux through the sea surface exposed to air due to sea ice reduction warms the atmospheric column. Warmer air increases the downward longwave radiation and subsequently surface air temperature, which facilitates sea surface remains to be free of ice. This positive feedback mechanism is not clearly observed in the Laptev, East Siberian, Chukchi, and Beaufort seas, since sea ice refreezes in late fall (November) before excessive turbulent heat flux is available for warming the atmospheric column in winter. A detailed seasonal heat budget is presented in order to understand specific differences between the Barents-Kara seas and Laptev, East Siberian, Chukchi, and Beaufort seas.

  20. Laser amplifier based on Raman amplification in plasma (Conference Presentation)

    Science.gov (United States)

    Vieux, Gregory; Cipiccia, Silvia; Lemos, Nuno R. C.; Ciocarlan, Cristian; Grant, Peter A.; Grant, David W.; Ersfeld, Bernhard; Hur, MinSup; Lepipas, Panagiotis; Manahan, Grace; Reboredo Gil, David; Subiel, Anna; Welsh, Gregor H.; Wiggins, S. Mark; Yoffe, Samuel R.; Farmer, John P.; Aniculaesei, Constantin; Brunetti, Enrico; Yang, Xue; Heathcote, Robert; Nersisyan, Gagik; Lewis, Ciaran L. S.; Pukhov, Alexander; Dias, João. Mendanha; Jaroszynski, Dino A.

    2017-05-01

    The increasing demand for high laser powers is placing huge demands on current laser technology. This is now reaching a limit, and to realise the existing new areas of research promised at high intensities, new cost-effective and technically feasible ways of scaling up the laser power will be required. Plasma-based laser amplifiers may represent the required breakthrough to reach powers of tens of petawatt to exawatt, because of the fundamental advantage that amplification and compression can be realised simultaneously in a plasma medium, which is also robust and resistant to damage, unlike conventional amplifying media. Raman amplification is a promising method, where a long pump pulse transfers energy to a lower frequency, short duration counter-propagating seed pulse through resonant excitation of a plasma wave that creates a transient plasma echelon that backscatters the pump into the probe. Here we present the results of an experimental campaign conducted at the Central Laser Facility. Pump pulses with energies up to 100 J have been used to amplify sub-nanojoule seed pulses to near-joule level. An unprecedented gain of eight orders of magnitude, with a gain coefficient of 180 cm-1 has been measured, which exceeds high-power solid-state amplifying media by orders of magnitude. High gain leads to strong competing amplification from noise, which reaches similar levels to the amplified seed. The observation of 640 Jsr-1 directly backscattered from noise, implies potential overall efficiencies greater than 10%.

  1. Enhanced sequencing coverage with digital droplet multiple displacement amplification.

    Science.gov (United States)

    Sidore, Angus M; Lan, Freeman; Lim, Shaun W; Abate, Adam R

    2016-04-20

    Sequencing small quantities of DNA is important for applications ranging from the assembly of uncultivable microbial genomes to the identification of cancer-associated mutations. To obtain sufficient quantities of DNA for sequencing, the small amount of starting material must be amplified significantly. However, existing methods often yield errors or non-uniform coverage, reducing sequencing data quality. Here, we describe digital droplet multiple displacement amplification, a method that enables massive amplification of low-input material while maintaining sequence accuracy and uniformity. The low-input material is compartmentalized as single molecules in millions of picoliter droplets. Because the molecules are isolated in compartments, they amplify to saturation without competing for resources; this yields uniform representation of all sequences in the final product and, in turn, enhances the quality of the sequence data. We demonstrate the ability to uniformly amplify the genomes of single Escherichia coli cells, comprising just 4.7 fg of starting DNA, and obtain sequencing coverage distributions that rival that of unamplified material. Digital droplet multiple displacement amplification provides a simple and effective method for amplifying minute amounts of DNA for accurate and uniform sequencing.

  2. Weak Value Amplification of a Post-Selected Single Photon

    Science.gov (United States)

    Hallaji, Matin

    Weak value amplification (WVA) is a measurement technique in which the effect of a pre- and post-selected system on a weakly interacting probe is magnified. In this thesis, I present the first experimental observation of WVA of a single photon. We observed that a signal photon --- sent through a polarization interferometer and post-selected by photodetection in the almost-dark port --- can act like eight photons. The effect of this single photon is measured as a nonlinear phase shift on a separate laser beam. The interaction between the two is mediated by a sample of laser- cooled 85Rb atoms. Electromagnetically induced transparency (EIT) is used to enhance the nonlinearity and overcome resonant absorption. I believe this work to be the first demonstration of WVA where a deterministic interaction is used to entangle two distinct optical systems. In WVA, the amplification is contingent on discarding a large portion of the original data set. While amplification increases measurement sensitivity, discarding data worsens it. Questioning whether these competing effects conspire to improve or diminish measurement accuracy has resulted recently in controversy. I address this question by calculating the maximum amount of information achievable with the WVA technique. By comparing this information to that achievable by the standard technique, where no post-selection is employed, I show that the WVA technique can be advantageous under a certain class of noise models. Finally, I propose a way to optimally apply the WVA technique.

  3. Ancient DNA: genomic amplification of Roman and medieval bovine bones

    Directory of Open Access Journals (Sweden)

    A. Valentini

    2010-04-01

    Full Text Available Cattle remains (bones and teeth of both roman and medieval age were collected in the archaeological site of Ferento (Viterbo, Italy with the aim of extracting and characterising nucleic acids. Procedures to minimize contamination with modern DNA and to help ancient DNA (aDNA preservation of the archaeological remains were adopted. Different techniques to extract aDNA (like Phenol/chloroform extraction from bovine bones were tested to identify the method that applies to the peculiar characteristics of the study site. Currently, aDNA investigation is mainly based on mtDNA, due to the ease of amplification of the small and high-copied genome and to its usefulness in evolutionary studies. Preliminary amplification of both mitochondrial and nuclear aDNA fragments from samples of Roman and medieval animals were performed and partial specific sequences of mitochondrial D-loop as well as of nuclear genes were obtained. The innovative amplification of nuclear aDNA could enable the analysis of genes involved in specific animal traits, giving insights of ancient economic and cultural uses, as well as providing information on the origin of modern livestock population.

  4. EGFR Amplification and Glioblastoma Stem-Like Cells

    Directory of Open Access Journals (Sweden)

    Katrin Liffers

    2015-01-01

    Full Text Available Glioblastoma (GBM, the most common malignant brain tumor in adults, contains a subpopulation of cells with a stem-like phenotype (GS-cells. GS-cells can be maintained in vitro using serum-free medium supplemented with epidermal growth factor, basic fibroblast growth factor-2, and heparin. However, this method does not conserve amplification of the Epidermal Growth Factor Receptor (EGFR gene, which is present in over 50% of all newly diagnosed GBM cases. GS-cells with retained EGFR amplification could overcome the limitations of current in vitro model systems and contribute significantly to preclinical research on EGFR-targeted therapy. This review recapitulates recent methodological approaches to expand stem-like cells from GBM with different EGFR status in order to maintain EGFR-dependent intratumoral heterogeneity in vitro. Further, it will summarize the current knowledge about the impact of EGFR amplification and overexpression on the stem-like phenotype of GBM-derived GS-cells and different approaches to target the EGFR-dependent GS-cell compartment of GBM.

  5. Current amplification models of sensorineurall and conductive hearing loss

    Directory of Open Access Journals (Sweden)

    Ostojić Sanja

    2012-01-01

    Full Text Available The main function of a hearing aid is to improve auditory and language abilities of hearing impaired users. The amplification model has to be adapted according to age, degree and type of hearing loss. The goal of this paper is to analyze the current amplification models of sensorineural and conductive hearing loss which can provide a high quality of speech perception and sounds at any degree of hearing loss. The BAHA is a surgically implantable system for treatment of conductive hearing loss that works through direct bone conduction. BAHA is used to help people with chronic ear infections, congenital external auditory canal atresia and single sided deafness who cannot benefit from conventional hearing aids. The last generation of hearing aid for sensorineural hearing loss is cochlear implant. Bimodal amplification improves binaural hearing. Hearing aids alone do not make listening easier in all situations. The things that can interfere with listening are background noises, distance from a sound and reverberation or echo. The device used most often today is the Frequency Modulated (FM system.

  6. Disturbance amplification in boundary layers over thin wall films

    Science.gov (United States)

    Saha, Sandeep; Page, Jacob; Zaki, Tamer A.

    2016-02-01

    In single-fluid boundary layers, streaks can amplify at sub-critical Reynolds numbers and initiate early transition to turbulence. Introducing a wall film of different viscosities can appreciably alter the stability of the base flow and, in particular, the transient growth of the perturbation streaks. The formalism of seminorms is used to identify optimal disturbances which maximize the kinetic energy in the two-fluid flow. An examination of optimal growth over a range of viscosity ratios of the film relative to the outer flow reveals three distinct regimes of amplification, each associated with a particular combination of the eigenfunctions. In order to elucidate the underlying amplification mechanisms, a model problem is formulated: An initial value problem is solved using an eigenfunction expansion and is used to compute the evolution of pairs of eigenfunctions. By appropriately selecting the pair, the initial value problem qualitatively reproduces the temporal evolution of the optimal disturbance, and provides an unambiguous explanation of the dynamics. Two regimes of transient growth are attributed to the evolution of the interface mode along with free-stream vortical modes; the third regime is due to the evolution of the interface and a discrete mode. The results demonstrate that a lower-viscosity film can effectively reduce the efficacy of the lift-up mechanism and, as a result, transient growth of disturbances. However, another mechanism of amplification of wall-normal vorticity arises due to the deformation of the two-fluid interface and becomes dominant below a critical viscosity ratio.

  7. Landfill gas

    Energy Technology Data Exchange (ETDEWEB)

    Willumsen, H. (Crone and Koch, Viborg (Denmark))

    1990-08-01

    In most landfills, the refuse deposit usually has a high content of organic matter consisting of a mixture of household, industrial and garden waste. Immediately after the refuse has been placed in the landfill, aerobic decomposition of the organic waste begins. Once the oxygen has been exhausted, anaerobic decomposition begins. 'Biogas' is produced which has a methane content of approximately 50% and can be used as a fuel. The exploitation of landfill gas for energy purposes was initiated in the USA around 1975 and later in Europe. A landfill gas plant consists of a recovery system and a production system. A recovery system can consist of vertical perforated pipe wells, horizontal perforated pipes or ditches, or membrane covers to collect the generated gas. Under normal conditions it will not be necessary to process the gas except for the removal of water and other impurities (e.g. solid particles) if the gas is to be used in a boiler or engine. In the USA most often only power is produced, whereas in Europe the waste heat is normally exploited, making the plant function as a combined power and heating plant. It is also possible to upgrade the landfill gas to a methane content of nearly 100, after which it can be distributed with natural gas. There are several such plants in the USA. 8 refs., 6 figs., 6 tabs.

  8. Polyethersulfone improves isothermal nucleic acid amplification compared to current paper-based diagnostics.

    Science.gov (United States)

    Linnes, J C; Rodriguez, N M; Liu, L; Klapperich, C M

    2016-04-01

    Devices based on rapid, paper-based, isothermal nucleic acid amplification techniques have recently emerged with the potential to fill a growing need for highly sensitive point-of-care diagnostics throughout the world. As this field develops, such devices will require optimized materials that promote amplification and sample preparation. Herein, we systematically investigated isothermal nucleic acid amplification in materials currently used in rapid diagnostics (cellulose paper, glass fiber, and nitrocellulose) and two additional porous membranes with upstream sample preparation capabilities (polyethersulfone and polycarbonate). We compared amplification efficiency from four separate DNA and RNA targets (Bordetella pertussis, Chlamydia trachomatis, Neisseria gonorrhoeae, and Influenza A H1N1) within these materials using two different isothermal amplification schemes, helicase dependent amplification (tHDA) and loop-mediated isothermal amplification (LAMP), and traditional PCR. We found that the current paper-based diagnostic membranes inhibited nucleic acid amplification when compared to membrane-free controls; however, polyethersulfone allowed for efficient amplification in both LAMP and tHDA reactions. Further, observing the performance of traditional PCR amplification within these membranes was not predicative of their effects on in situ LAMP and tHDA. Polyethersulfone is a new material for paper-based nucleic acid amplification, yet provides an optimal support for rapid molecular diagnostics for point-of-care applications.

  9. Comparison between NuGEN's WT-Ovation Pico and one-direct amplification systems.

    Science.gov (United States)

    Morse, Alison M; Carballo, Valentina; Baldwin, Donald A; Taylor, Christopher G; McIntyre, Lauren M

    2010-09-01

    Differential gene expression between groups of homogenous cell types is a biological question whose time has come. RNA can be extracted from small numbers of cells, such as those isolated by laser-capture microdissection, but the small amounts obtained often require amplification to enable whole genome transcriptome profiling by technologies such as microarray analysis and RNA-seq. Recently, advances in amplification procedures make amplification directly from whole cell lysates possible. The aim of this study was to compare two amplification systems for variations in observed RNA abundance attributable to the amplification procedure for use with small quantities of cells isolated by laser-capture microdissection. Arabidopsis root cells undergoing giant cell formation as a result of nematode infestation and uninfested control root cells were laser-captured and used to evaluate two amplification systems. One, NuGEN's WT-Ovation Pico (Pico) amplification system, uses total RNA as starting material, and the other, NuGEN's WT-One-Direct (One-Direct) amplification system, uses lysate containing the captured cells. The reproducibility of whole genome transcript profiling and correlations of both systems were investigated after microarray analysis. The One-Direct system was less reproducible and more variable than the Pico system. The Pico amplification kit resulted in the detection of thousands of differentially expressed genes between giant cells and control cells. This is in marked contrast to the relatively few genes detected after amplification with the One-Direct amplification kit.

  10. Genome-wide gene amplification during differentiation of neural progenitor cells in vitro.

    Science.gov (United States)

    Fischer, Ulrike; Keller, Andreas; Voss, Meike; Backes, Christina; Welter, Cornelius; Meese, Eckart

    2012-01-01

    DNA sequence amplification is a phenomenon that occurs predictably at defined stages during normal development in some organisms. Developmental gene amplification was first described in amphibians during gametogenesis and has not yet been described in humans. To date gene amplification in humans is a hallmark of many tumors. We used array-CGH (comparative genomic hybridization) and FISH (fluorescence in situ hybridization) to discover gene amplifications during in vitro differentiation of human neural progenitor cells. Here we report a complex gene amplification pattern two and five days after induction of differentiation of human neural progenitor cells. We identified several amplified genes in neural progenitor cells that are known to be amplified in malignant tumors. There is also a striking overlap of amplified chromosomal regions between differentiating neural progenitor cells and malignant tumor cells derived from astrocytes. Gene amplifications in normal human cells as physiological process has not been reported yet and may bear resemblance to developmental gene amplifications in amphibians and insects.

  11. Amplification of seismic ground motion in the Tunis basin: Numerical BEM simulations vs experimental evidences

    CERN Document Server

    Kham, Marc; Bouden-Romdhane, Nejla

    2013-01-01

    This paper aims at the analysis of seismic wave amplification in a deep alluvial basin in the city of Tunis in Tunisia. This sedimentary basin is 3000m wide and 350m deep. Since the seismic hazard is significant in this area, the depth of the basin and the strong impedance ratio raise the need for an accurate estimation of seismic motion amplification. Various experimental investigations were performed in previous studies to characterize site effects. The Boundary Element Method is considered herein to assess the parameter sensitivity of the amplification process and analyse the prevailing phenomena. The various frequencies of maximum amplification are correctly estimated by the BEM simulations. The maximum amplification level observed in the field is also well retrieved by the numerical simulations but, due to the sensitivity of the location of maximum amplification in space, the overall maximum amplification has to be considered. The influence of the wave-field incidence and material damping is also discuss...

  12. Gas turbines

    Energy Technology Data Exchange (ETDEWEB)

    Farahan, E.; Eudaly, J.P.

    1978-10-01

    This evaluation provides performance and cost data for commercially available simple- and regenerative-cycle gas turbines. Intercooled, reheat, and compound cycles are discussed from theoretical basis only, because actual units are not currently available, except on a special-order basis. Performance characteristics investigated include unit efficiency at full-load and off-design conditions, and at rated capacity. Costs are tabulated for both simple- and regenerative-cycle gas turbines. The output capacity of the gas turbines investigated ranges from 80 to 134,000 hp for simple units and from 12,000 to 50,000 hp for regenerative units.

  13. Gas hydrates

    Digital Repository Service at National Institute of Oceanography (India)

    Ramprasad, T.

    and the role it plays in the global climate and the future of fuels. Russia, Japan, Nigeria, Peru, Chile, Pakistan, Indonesia, Korea, etc are various countries who are perusing the gas hydrates studies as a future resource for fuel. Indian Initiative..., 1993, Free gas at the base of the gas hydrate zone in the vicinity of the Chile Triple junction: Geology, v. 21, pp. 905-908. Borowski, W.S., C.K. Paull, and U. William, III, 1999, Global and local variations of interstitial sulfate gradients...

  14. Gas gangrene

    Science.gov (United States)

    ... also can be caused by group A streptococcus, Staphylococcus aureus, and Vibrio vulnificus . Clostridium is found nearly everywhere. As the bacteria grow inside the body, it makes gas and harmful substances (toxins) that can damage body tissues, cells, and blood ...

  15. A new integrated photosensor for gas proportional scintillation counters based on the gas electron multiplier (GEM)

    CERN Document Server

    Lopes, J A M; Conde, C A N; Morgado, R E

    1999-01-01

    The performance of a novel integrated photosensor for use in a xenon gas proportional scintillation detector is described. Earlier integrated photo-sensor designs were limited in charge gains due to the onset of electrical breakdown, which was ascribed to optical positive feedback from scintillation photons produced in the charge amplification stage. The present design uses a gas electron multiplier (GEM) composed of a 50 mu m thick Kapton film with copper-plated electrode surfaces on both sides and perforated with 200 mu m holes at a 300 mu m pitch. The front surface is made photosensitive with a 150-nm-thick CsI film. When an appropriate voltage is applied between the copper electrodes, the resulting electric field directs photoelectrons produced on the front surface through the holes in the GEM and onto a wire chamber where charge amplification occurs. Optical positive feedback is essentially eliminated since the charge amplification stage is optically de-coupled from the photocathode. The GEM also provide...

  16. Isothermal strand displacement amplification (iSDA): a rapid and sensitive method of nucleic acid amplification for point-of-care diagnosis.

    Science.gov (United States)

    Toley, Bhushan J; Covelli, Isabela; Belousov, Yevgeniy; Ramachandran, Sujatha; Kline, Enos; Scarr, Noah; Vermeulen, Nic; Mahoney, Walt; Lutz, Barry R; Yager, Paul

    2015-11-21

    We present a method of rapid isothermal amplification of DNA without initial heat denaturation of the template, and methods and probes for (a) real-time fluorescence detection and (b) lateral flow detection of amplicons. Isothermal strand displacement amplification (iSDA) can achieve >10(9)-fold amplification of the target sequence in isothermal DNA amplification methods. iSDA initiates at sites where DNA base pairs spontaneously open or transiently convert into Hoogsteen pairs, i.e. "breathe", and proceeds to exponential amplification by repeated nicking, extension, and displacement of single strands. We demonstrate successful iSDA amplification and lateral flow detection of 10 copies of a Staphylococcus aureus gene, NO.-inducible l-lactate dehydrogenase (ldh1) (Richardson, Libby, and Fang, Science, 2008, 319, 1672-1676), in a clean sample and 50 copies in the presence of high concentrations of genomic DNA and mucins in isothermal amplification reactions. Finally, we demonstrate the multiplexing capability of iSDA by the simultaneous amplification of the target gene and an engineered internal control sequence. The speed, sensitivity, and specificity of iSDA make it a powerful method for point-of-care molecular diagnosis.

  17. KRAS and MAPK1 Gene Amplification in Type II Ovarian Carcinomas

    Directory of Open Access Journals (Sweden)

    Noriyuki Ishikawa

    2013-07-01

    Full Text Available In this study, we examined the clinical significance of KRAS and MAPK1 amplification and assessed whether these amplified genes were potential therapeutic targets in type II ovarian carcinoma. Using fluorescence in situ hybridization, immunohistochemistry, and retrospectively collected clinical data, KRAS and MAPK1 amplifications were identified in 9 (13.2% and 5 (7.4% of 68 type II ovarian carcinoma tissue samples, respectively. Interestingly, co-amplification of KRAS and MAPK1 seemed to be absent in the type II ovarian carcinomas tested, except one case. Active phospho-ERK1/2 was identified in 26 (38.2% out of 68 type II ovarian carcinomas and did not correlate with KRAS or MAPK1 amplification. There was no significant relationship between KRAS amplification and overall or progression-free survival in patients with type II ovarian carcinoma. However, patients with MAPK1 amplification had significantly poorer progression-free survival than patients without MAPK1 amplification. Moreover, type II ovarian carcinoma cells with concomitant KRAS amplification and mutation exhibited dramatic growth reduction following treatment with the MEK inhibitor PD0325901. These findings indicate that KRAS/MAPK1 amplification is critical for the growth of a subset of type II ovarian carcinomas. Additionally, RAS/RAF/MEK/ERK pathway-targeted therapy may benefit selected patients with type II ovarian carcinoma harboring KRAS/MAPK1 amplifications.

  18. Randomness Amplification under Minimal Fundamental Assumptions on the Devices

    Science.gov (United States)

    Ramanathan, Ravishankar; Brandão, Fernando G. S. L.; Horodecki, Karol; Horodecki, Michał; Horodecki, Paweł; Wojewódka, Hanna

    2016-12-01

    Recently, the physically realistic protocol amplifying the randomness of Santha-Vazirani sources producing cryptographically secure random bits was proposed; however, for reasons of practical relevance, the crucial question remained open regarding whether this can be accomplished under the minimal conditions necessary for the task. Namely, is it possible to achieve randomness amplification using only two no-signaling components and in a situation where the violation of a Bell inequality only guarantees that some outcomes of the device for specific inputs exhibit randomness? Here, we solve this question and present a device-independent protocol for randomness amplification of Santha-Vazirani sources using a device consisting of two nonsignaling components. We show that the protocol can amplify any such source that is not fully deterministic into a fully random source while tolerating a constant noise rate and prove the composable security of the protocol against general no-signaling adversaries. Our main innovation is the proof that even the partial randomness certified by the two-party Bell test [a single input-output pair (u* , x* ) for which the conditional probability P (x*|u*) is bounded away from 1 for all no-signaling strategies that optimally violate the Bell inequality] can be used for amplification. We introduce the methodology of a partial tomographic procedure on the empirical statistics obtained in the Bell test that ensures that the outputs constitute a linear min-entropy source of randomness. As a technical novelty that may be of independent interest, we prove that the Santha-Vazirani source satisfies an exponential concentration property given by a recently discovered generalized Chernoff bound.

  19. Phonon amplification using evaporation and adsorption of helium

    Energy Technology Data Exchange (ETDEWEB)

    More, T.; Adams, J.S.; Bandler, S.R.; Broueer, S.M.; Lanou, R.E.; Maris, H.J.; Seidel, G.M. [Department of Physics, Brown University, Providence, Rhode Island 02912 (United States)

    1996-07-01

    We report the results of experiments designed to investigate the feasibility of amplifying a phonon signal using the evaporation of helium from a superfluid film and its subsequent readsorption onto a helium-free surface. We envision a multistage amplifier in which helium is evaporated from a wafer with a helium film only on one side and then adsorbed onto the film-free surface of a similar wafer. The phonons created by the adsorption reach the film on the opposite side of the wafer and potentially desorb more helium than was evaporated by the first wafer. The amplification would come from the high ratio of the binding energy of a helium atom to a film-free surface relative to the binding energy to the liquid. A number of experiments are reported that investigate the efficiencies of the individual steps of the process. The gain per stage is found to be about 3 for high-energy densities in which multiphonon processes are possible. At low-energy densities, the energy deposited into a film-free wafer is found to be less than the original input energy, with the ratio of output to input energy 0.2. Since in applications requiring amplification the phonon density produced by the adsorption of helium on a wafer will be low, the configuration we have studied{emdash}phonons produced in silicon coated with a saturated {sup 4}He film{emdash}will not result in amplification. However, other configurations might improve the efficiency enough to make an amplifier possible. {copyright} {ital 1996 The American Physical Society.}

  20. Astigmatism transfer phenomena in the optical parametric amplification process

    Science.gov (United States)

    Li, Wenkai; Chen, Yun; Li, Yanyan; Xu, Yi; Guo, Xiaoyang; Lu, Jun; Leng, Yuxin

    2017-01-01

    We numerically and experimentally investigate the astigmatism transfer phenomena in femtosecond optical parametric amplification (OPA). We model the OPA process based on the coupled second-order three-wave nonlinear propagation equations. The numerical and experimental results support that the input pump pulse astigmatism can be transferred into the idler pulse but not the signal pulse, and the idler pulse astigmatism originating from spatial walk-off is less than the idler pulse astigmatism received from the pump. Thus, we can provide a clear understanding of astigmatism transfer mechanisms in the OPA process, and make better use of broadband tunable OPA sources.

  1. Amplification of Tau fibrils from minute quantities of seeds.

    Science.gov (United States)

    Meyer, Virginia; Dinkel, Paul D; Rickman Hager, Emily; Margittai, Martin

    2014-09-16

    The propagation of Tau pathology in Alzheimer's disease (AD) is thought to proceed through templated conversion of Tau protein into fibrils and cell-to-cell transfer of elongation-competent seeds. To investigate the efficiency of Tau conversion, we adapted the protein misfolding cyclic amplification assay used for the conversion of prions. Utilizing heparin as a cofactor and employing repetitive cycles of shearing and growth, synthetic Tau fibrils and Tau fibrils in AD brain extract are progressively amplified. Concurrently, self-nucleation is suppressed. The results highlight breakage-induced replication of Tau fibrils as a potential facilitator of disease spread.

  2. Simultaneous amplification and attenuation in isotropic chiral materials

    Science.gov (United States)

    Mackay, Tom G.; Lakhtakia, Akhlesh

    2016-05-01

    The electromagnetic field phasors in an isotropic chiral material (ICM) are superpositions of two Beltrami fields of different handedness. Application of the Bruggeman homogenization formalism to two-component composite materials delivers ICMs wherein Beltrami fields of one handedness attenuate whereas Beltrami fields of the other handedness amplify. One component material is a dissipative ICM, the other an active dielectric material. The range of the volume fraction of the active component material for which simultaneous amplification and attenuation is exhibited decreases—but does not vanish—as the ICM component becomes more dissipative and as its chirality parameter reduces in magnitude.

  3. Rapid detection of Mycobacterium tuberculosis by recombinase polymerase amplification.

    Directory of Open Access Journals (Sweden)

    David S Boyle

    Full Text Available Improved access to effective tests for diagnosing tuberculosis (TB has been designated a public health priority by the World Health Organisation. In high burden TB countries nucleic acid based TB tests have been restricted to centralised laboratories and specialised research settings. Requirements such as a constant electrical supply, air conditioning and skilled, computer literate operators prevent implementation of such tests in many settings. Isothermal DNA amplification technologies permit the use of simpler, less energy intensive detection platforms more suited to low resource settings that allow the accurate diagnosis of a disease within a short timeframe. Recombinase Polymerase Amplification (RPA is a rapid, low temperature isothermal DNA amplification reaction. We report here RPA-based detection of Mycobacterium tuberculosis complex (MTC DNA in <20 minutes at 39 °C. Assays for two MTC specific targets were investigated, IS6110 and IS1081. When testing purified MTC genomic DNA, limits of detection of 6.25 fg (IS6110 and 20 fg (IS1081were consistently achieved. When testing a convenience sample of pulmonary specimens from suspected TB patients, RPA demonstrated superior accuracy to indirect fluorescence microscopy. Compared to culture, sensitivities for the IS1081 RPA and microscopy were 91.4% (95%CI: 85, 97.9 and 86.1% (95%CI: 78.1, 94.1 respectively (n = 71. Specificities were 100% and 88.6% (95% CI: 80.8, 96.1 respectively. For the IS6110 RPA and microscopy sensitivities of 87.5% (95%CI: 81.7, 93.2 and 70.8% (95%CI: 62.9, 78.7 were obtained (n = 90. Specificities were 95.4 (95% CI: 92.3,98.1 and 88% (95% CI: 83.6, 92.4 respectively. The superior specificity of RPA for detecting tuberculosis was due to the reduced ability of fluorescence microscopy to distinguish Mtb complex from other acid fast bacteria. The rapid nature of the RPA assay and its low energy requirement compared to other amplification technologies suggest RPA-based TB

  4. Limits of Femtosecond Fiber Amplification by Parabolic Pre-Shaping

    CERN Document Server

    Fu, Walter; McComb, Timothy S; Lowder, Tyson L; Wise, Frank W

    2016-01-01

    We explore parabolic pre-shaping as a means of generating and amplifying ultrashort pulses. We develop a theoretical framework for modeling the technique and use its conclusions to design a femtosecond fiber amplifier. Starting from 9 ps pulses, we obtain 4.3 $\\mu$J, nearly transform-limited pulses 275 fs in duration, simultaneously achieving over 40 dB gain and 33-fold compression. Finally, we show that this amplification scheme is limited by Raman scattering, and outline a method by which the pulse duration and energy may be further improved and tailored for a given application.

  5. Limits of Femtosecond Fiber Amplification by Parabolic Pre-Shaping.

    Science.gov (United States)

    Fu, Walter; Tang, Yuxing; McComb, Timothy S; Lowder, Tyson L; Wise, Frank W

    2017-03-01

    We explore parabolic pre-shaping as a means of generating and amplifying ultrashort pulses. We develop a theoretical framework for modeling the technique and use its conclusions to design a femtosecond fiber amplifier. Starting from 9 ps pulses, we obtain 4.3 μJ, nearly transform-limited pulses 275 fs in duration, simultaneously achieving over 40 dB gain and 33-fold compression. Finally, we show that this amplification scheme is limited by Raman scattering, and outline a method by which the pulse duration and energy may be further improved and tailored for a given application.

  6. Utilization of non-linear converters for audio amplification

    DEFF Research Database (Denmark)

    Iversen, Niels Elkjær; Birch, Thomas; Knott, Arnold

    2012-01-01

    Class D amplifiers fits the automotive demands quite well. The traditional buck-based amplifier has reduced both the cost and size of amplifiers. However the buck topology is not without its limitations. The maximum peak AC output voltage produced by the power stage is only equal the supply voltage....... The introduction of non-linear converters for audio amplification defeats this limitation. A Cuk converter, designed to deliver an AC peak output voltage twice the supply voltage, is presented in this paper. A 3V prototype has been developed to prove the concept. The prototype shows that it is possible to achieve...

  7. Precision phase estimation based on weak-value amplification

    Science.gov (United States)

    Qiu, Xiaodong; Xie, Linguo; Liu, Xiong; Luo, Lan; Li, Zhaoxue; Zhang, Zhiyou; Du, Jinglei

    2017-02-01

    In this letter, we propose a precision method for phase estimation based on the weak-value amplification (WVA) technique using a monochromatic light source. The anomalous WVA significantly suppresses the technical noise with respect to the intensity difference signal induced by the phase delay when the post-selection procedure comes into play. The phase measured precision of this method is proportional to the weak-value of a polarization operator in the experimental range. Our results compete well with the wide spectrum light phase weak measurements and outperform the standard homodyne phase detection technique.

  8. Weak value amplification in a shot-noise limited interferometer

    CERN Document Server

    Nishizawa, Atsushi; Fujimoto, Masa-Katsu

    2012-01-01

    We study the weak-value amplification (WVA) in a phase measurement with an optical interferometer in which shot noise limits the sensitivity. We compute the signal and the shot noise including the full-order interaction terms of the WVA, and show that the shot-noise contribution to a phase shift in a pointer variable is always larger than the final variance of the pointer variable. To clarify an advantage for practical uses of the WVA, we discuss signal-to-noise ratio and its optimization in the presence of the shot noise.

  9. Direct field measurement of the dynamic amplification in a bridge

    Science.gov (United States)

    Carey, Ciarán; OBrien, Eugene J.; Malekjafarian, Abdollah; Lydon, Myra; Taylor, Su

    2017-02-01

    In this paper, the level of dynamics, as described by the Assessment Dynamic Ratio (ADR), is measured directly through a field test on a bridge in the United Kingdom. The bridge was instrumented using fiber optic strain sensors and piezo-polymer weigh-in-motion sensors were installed in the pavement on the approach road. Field measurements of static and static-plus-dynamic strains were taken over 45 days. The results show that, while dynamic amplification is large for many loading events, these tend not to be the critical events. ADR, the allowance that should be made for dynamics in an assessment of safety, is small.

  10. Gene amplification during differentiation of mammalian neural stem cells in vitro and in vivo.

    Science.gov (United States)

    Fischer, Ulrike; Backes, Christina; Raslan, Abdulrahman; Keller, Andreas; Meier, Carola; Meese, Eckart

    2015-03-30

    In development of amphibians and flies, gene amplification is one of mechanisms to increase gene expression. In mammalian cells, gene amplification seems to be restricted to tumorigenesis and acquiring of drug-resistance in cancer cells. Here, we report a complex gene amplification pattern in mouse neural progenitor cells during differentiation with approximately 10% of the genome involved. Half of the amplified mouse chromosome regions overlap with amplified regions previously reported in human neural progenitor cells, indicating conserved mechanisms during differentiation. Using fluorescence in situ hybridization, we verified the amplification in single cells of primary mouse mesencephalon E14 (embryonic stage) neurosphere cells during differentiation. In vivo we confirmed gene amplifications of the TRP53 gene in cryosections from mouse embryos at stage E11.5. Gene amplification is not only a cancer-related mechanism but is also conserved in evolution, occurring during differentiation of mammalian neural stem cells.

  11. A cascade amplification strategy based on rolling circle amplification and hydroxylamine amplified gold nanoparticles enables chemiluminescence detection of adenosine triphosphate.

    Science.gov (United States)

    Wang, Ping; Zhang, Tonghuan; Yang, Taoyi; Jin, Nan; Zhao, Yanjun; Fan, Aiping

    2014-08-07

    A highly sensitive and selective chemiluminescent (CL) biosensor for adenosine triphosphate (ATP) was developed by taking advantage of the ATP-dependent enzymatic reaction (ATP-DER), the powerful signal amplification capability of rolling circle amplification (RCA), and hydroxylamine-amplified gold nanoparticles (Au NPs). The strategy relies on the ability of ATP, a cofactor of T4 DNA ligase, to trigger the ligation-RCA reaction. In the presence of ATP, the T4 DNA ligase catalyzes the ligation reaction between the two ends of the padlock probe, producing a closed circular DNA template that initiates the RCA reaction with phi29 DNA polymerase and dNTP. Therein, many complementary copies of the circular template can be generated. The ATP-DER is eventually converted into a detectable CL signal after a series of processes, including gold probe hybridization, hydroxylamine amplification, and oxidative gold metal dissolution coupled with a simple and sensitive luminol CL reaction. The CL signal is directly proportional to the ATP level. The results showed that the detection limit of the assay is 100 pM of ATP, which compares favorably with those of other ATP detection techniques. In addition, by taking advantage of ATP-DER, the proposed CL sensing system exhibits extraordinary specificity towards ATP and could distinguish the target molecule ATP from its analogues. The proposed method provides a new and versatile platform for the design of novel DNA ligation reaction-based CL sensing systems for other cofactors. This novel ATP-DER based CL sensing system may find wide applications in clinical diagnosis as well as in environmental and biomedical fields.

  12. Ultrasensitive electrochemical DNA assay based on counting of single magnetic nanobeads by a combination of DNA amplification and enzyme amplification.

    Science.gov (United States)

    Zhang, Xiaoli; Li, Linlin; Li, Lu; Chen, Jia; Zou, Guizheng; Si, Zhikun; Jin, Wenrui

    2009-03-01

    An ultrasensitive electrochemical method for determination of DNA is developed based on counting of single magnetic nanobeads (MNBs) corresponding to single DNA sequences combined with a double amplification (DNA amplification and enzyme amplification). In this method, target DNA (t-DNA) is captured on a streptavidin-coated substrate via biotinylated capture DNA. Then, MNBs functionalized with first-probe DNAs (p1-DNA-MNBs) are conjugated to t-DNA sequences with a ratio of 1:1. Subsequently, the p1-DNA-MNBs are released from the substrate via dehybridization. The released p1-DNA-MNBs are labeled with alkaline phosphatase (AP) using biotinylated second-probe DNAs (p2-DNAs) and streptavidin-AP conjugates. The resultant AP-p2-DNA-p1-DNA-MNBs with enzyme substrate disodium phenyl phosphate (DPP) are continuously introduced through a capillary as the microsampler and microreactor at 40 degrees C. AP on the AP-p2-DNA-p1-DNA-MNBs converts a huge number of DPP into its product phenol, and phenol zones are produced around each moving AP-p2-DNA-p1-DNA-MNB. The phenol zones are continuously delivered to the capillary outlet and detected by a carbon fiber disk bundle electrode at 1.05 V. An elution curve with peaks is obtained. Each peak is corresponding to a phenol zone relative to single t-DNA sequence. The peaks on the elution curve are counted for quantification. The number of the peaks is proportional to the concentration of t-DNA in a range of 5.0 x 10(-16) to 1.0 x 10(-13) mol/L.

  13. STUDY OF SOIL AMPLIFICATION BASED ON MICROTREMOR AND SEISMIC RECORDS IN LIMA PERU

    Science.gov (United States)

    Calderon, Diana; Sekiguchi, Toru; Nakai, Shoichi; Aguilar, Zenon; Lazares, Fernando

    The dynamic characteristics of the ground in Lima, capital of Peru, specifically the amplification are investigated. By using the small and large microtremor array measurements we estimated the soil velocity profiles with depths to the bedrock in many cases. These profiles were used to estimate the amplification factors. Important results are the large amplification factors at EMO, VSV, CAL and CMA (La Molina, Villa El Salvador, El Callao and Bellavista district, respectively).

  14. One-pot isothermal DNA amplification Hybridisation and detection by a disc-based method

    OpenAIRE

    2014-01-01

    [EN] An integrated sensor comprising isothermal DNA amplification and in situ detection is presented. The method principle is based on recombinase polymerase amplification (RPA) and detection in the microarray format by compact disc technology as a high-throughput sensing platform. Primers were immobilised on the polycarbonate surface of digital versatile discs (DVD) and, after hemi-nested amplification, multiplexing identification of each tethered product was achieved by optical scanning wit...

  15. Fourth-order-dispersion limitations of aberration-free chirped-pulse amplification systems

    Energy Technology Data Exchange (ETDEWEB)

    Kane, S. [Center for Ultrafast Optical Science, University of Michigan, 2200 Bonisteel Boulevard, Room 1006, Institute for Science and Technology Building, Ann Arbor, Michigan 48109-2099 (United States); Squier, J. [Institute for Nonlinear Science, University of California, San Diego, Urey Hall, Mail Code 0339, La Jolla, California 92093-0339 (United States)

    1997-05-01

    To obtain shorter pulses in chirped-pulse-amplification lasers, researchers have recently proposed several designs for aberration-free pulse stretchers. We examine the limitations of two aberration-free chirped-pulse-amplification systems and show that comparable results can be obtained with simpler, conventional pulse stretchers. In addition, we present a simple, quintic-phase-limited, aberration-free chirped-pulse-amplification system that can support ultrashort, high-contrast pulses. {copyright} 1997 Optical Society of America

  16. Social amplification of risk in the Internet environment.

    Science.gov (United States)

    Chung, Ik Jae

    2011-12-01

    This article analyzes the dynamic process of risk amplification in the Internet environment with special emphasis on public concern for environmental risks from a high-speed railway tunnel construction project in South Korea. Environmental organizations and activists serving as social stations collected information about the project and its ecological impact, and communicated this with the general public, social groups, and institutions. The Internet provides social stations and the public with an efficient means for interactive communication and an open space for active information sharing and public participation. For example, while the website of an organization such as an environmental activist group can initially trigger local interest, the Internet allows this information to be disseminated to a much wider audience in a manner unavailable to the traditional media. Interaction among social stations demonstrates an amplifying process of public attention to the risk. Analyses of the volume of readers' comments to online newspaper articles and public opinions posted on message board of public and nonprofit organizations show the ripple effects of the amplification process as measured along temporal, geographical, and sectoral dimensions. Public attention is also influenced by the symbolic connotations of risk information. Interpretations of risk in religious, political, or legal terms intensify public concern for the environmental risk. © 2011 Society for Risk Analysis.

  17. Health Risk Information Engagement and Amplification on Social Media.

    Science.gov (United States)

    Strekalova, Yulia A

    2017-04-01

    Emerging pandemics call for unique health communication and education strategies in which public health agencies need to satisfy the public's information needs about possible risks while preventing risk exaggeration and dramatization. As a route to providing a framework for understanding public information behaviors in response to an emerging pandemic, this study examined the characteristics of communicative behaviors of social media audiences in response to Ebola outbreak news. Grounded in the social amplification of risks framework, this study adds to an understanding of information behaviors of online audiences by showing empirical differences in audience engagement with online health information. The data were collected from the Centers for Disease Control and Prevention (CDC) Facebook channel. The final data set included 809 CDC posts and 35,916 audience comments. The analysis identified the differences in audience information behaviors in response to an emerging pandemic, Ebola, and health promotion posts. While the CDC had fewer posts on Ebola than health promotion topics, the former received more attention from active page users. Furthermore, audience members who actively engaged with Ebola news had a small overlap with those who engaged with non-Ebola information during the same period. Overall, this study demonstrated that information behavior and audience engagement is topic dependent. Furthermore, audiences who commented on news about an emerging pandemic were homogenous and varied in their degree of information amplification.

  18. DNA Extraction and Amplification from Contemporary Polynesian Bark-Cloth

    Science.gov (United States)

    Moncada, Ximena; Payacán, Claudia; Arriaza, Francisco; Lobos, Sergio; Seelenfreund, Daniela; Seelenfreund, Andrea

    2013-01-01

    Background Paper mulberry has been used for thousands of years in Asia and Oceania for making paper and bark-cloth, respectively. Museums around the world hold valuable collections of Polynesian bark-cloth. Genetic analysis of the plant fibers from which the textiles were made may answer a number of questions of interest related to provenance, authenticity or species used in the manufacture of these textiles. Recovery of nucleic acids from paper mulberry bark-cloth has not been reported before. Methodology We describe a simple method for the extraction of PCR-amplifiable DNA from small samples of contemporary Polynesian bark-cloth (tapa) using two types of nuclear markers. We report the amplification of about 300 bp sequences of the ITS1 region and of a microsatellite marker. Conclusions Sufficient DNA was retrieved from all bark-cloth samples to permit successful PCR amplification. This method shows a means of obtaining useful genetic information from modern bark-cloth samples and opens perspectives for the analyses of small fragments derived from ethnographic materials. PMID:23437166

  19. DNA extraction and amplification from contemporary Polynesian bark-cloth.

    Directory of Open Access Journals (Sweden)

    Ximena Moncada

    Full Text Available BACKGROUND: Paper mulberry has been used for thousands of years in Asia and Oceania for making paper and bark-cloth, respectively. Museums around the world hold valuable collections of Polynesian bark-cloth. Genetic analysis of the plant fibers from which the textiles were made may answer a number of questions of interest related to provenance, authenticity or species used in the manufacture of these textiles. Recovery of nucleic acids from paper mulberry bark-cloth has not been reported before. METHODOLOGY: We describe a simple method for the extraction of PCR-amplifiable DNA from small samples of contemporary Polynesian bark-cloth (tapa using two types of nuclear markers. We report the amplification of about 300 bp sequences of the ITS1 region and of a microsatellite marker. CONCLUSIONS: Sufficient DNA was retrieved from all bark-cloth samples to permit successful PCR amplification. This method shows a means of obtaining useful genetic information from modern bark-cloth samples and opens perspectives for the analyses of small fragments derived from ethnographic materials.

  20. Method Of Signal Amplification In Multi-Chromophore Luminescence Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Levitsky, Igor A. (Fall River, MA); Krivoshlykov, Sergei G. (Shrewsbury, MA)

    2004-02-03

    A fluorescence-based method for highly sensitive and selective detection of analyte molecules is proposed. The method employs the energy transfer between two or more fluorescent chromophores in a carefully selected polymer matrix. In one preferred embodiment, signal amplification has been achieved in the fluorescent sensing of dimethyl methylphosphonate (DMMP) using two dyes, 3-aminofluoranthene (AM) and Nile Red (NR), in a hydrogen bond acidic polymer matrix. The selected polymer matrix quenches the fluorescence of both dyes and shifts dye emission and absorption spectra relative to more inert matrices. Upon DMMP sorption, the AM fluorescence shifts to the red at the same time the NR absorption shifts to the blue, resulting in better band overlap and increased energy transfer between chromophores. In another preferred embodiment, the sensitive material is incorporated into an optical fiber system enabling efficient excitation of the dye and collecting the fluorescent signal form the sensitive material on the remote end of the system. The proposed method can be applied to multichromophore luminescence sensor systems incorporating N-chromophores leading to N-fold signal amplification and improved selectivity. The method can be used in all applications where highly sensitive detection of basic gases, such as dimethyl methylphosphonate (DMMP), Sarin, Soman and other chemical warfare agents having basic properties, is required, including environmental monitoring, chemical industry and medicine.

  1. Generalized modulational instability in multimode fibers: wideband multimode parametric amplification

    CERN Document Server

    Guasoni, M

    2015-01-01

    In this paper intermodal modulational instability (IM-MI) is analyzed in a multimode fiber where several spatial and polarization modes propagate. The coupled nonlinear Schr\\"{o}dinger equations describing the modal evolution in the fiber are linearized and reduced to an eigenvalue problem. As a result, the amplification of each mode can be described by means of the eigenvalues and eigenvectors of a matrix that stores the information about the dispersion properties of the modes and the modal power distribution of the pump. Some useful analytical formulas are also provided that estimate the modal amplification as function of the system parameters. Finally, the impact of third-order dispersion and of absorbtion losses is evaluated, which reveals some surprising phenomena into the IM-MI dynamics. These outcomes generalize previous studies on bimodal-MI, related to the interaction between 2 spatial or polarization modes, to the most general case of $N>2$ interacting modes. Moreover, they pave the way towards the ...

  2. Radiopolymerization of {beta}(-)pinene: A case of chiral amplification

    Energy Technology Data Exchange (ETDEWEB)

    Cataldo, Franco [Soc. Lupi Chemical Research, Via Casilina 1626/A, 00133 Rome (Italy)]. E-mail: cdcata@flashnet.it; Keheyan, Yeghis [CNR, Istituto per lo studio dei Materiali Nanostrutturati, Department of Chemistry, University ' La Sapienza' , P.le Aldo Moro 1, Rome (Italy)

    2006-05-15

    {beta}(-)Pinene was treated with {gamma} radiation at three dose levels: 150, 300 and 600 kGy. The expected effect of radiation at these high doses was the partial racemization of the substrate as already observed in the case of other terpene monomers. Unexpectedly {beta}(-)pinene underwent a radiopolymerization reaction into a solid resin and into a dimer. The structure of the products was studied by FT-IR spectroscopy also in comparison to a reference {beta}(-)pinene resin prepared by cationic polymerization. A highly ordered structure was found in the case of the radiopolymer in comparison to the resin from cationic polymerization. Polarimetric measurements have shown astonishing enhancement in the optical activity of the radiopolymer and radiodimer in comparison to the starting optical activity of the {beta}(-)pinene monomer. The results have been discussed in terms of amplification of chirality caused by {gamma} radiation and the implications of this fact on the mechanism of chiral amplification on prebiotic molecules.

  3. Development and Application of Surface Plasmon Polaritons on Optical Amplification

    Directory of Open Access Journals (Sweden)

    Tong Zhang

    2014-01-01

    Full Text Available Propagation of surface plasmon polaritons (SPPs along the interface between a metal and a dielectric has attracted significant attention due to its unique optical properties, which has inspired a plethora of fascinating applications in photonics and optoelectronics. However, SPPs suffer from large attenuation because of the ohmic losses in the metal layer. It has become the main bottom-neck problem for the development of high performance plasmonic devices. This limitation can be overcome by providing the material adjacent to the metal with optical gain. In this paper, a review of gain compensation to SPPs is presented. We focus on the spontaneous radiation amplification and simulated radiation amplification. The ohmic loss of metal was greatly improved by introducing optical gain. Then we introduce several gain mediums of dye doped, quantum dots, erbium ion, and semiconductor to compensate optical loss of SPPs. Using gain medium mentioned above can compensate losses and achieve many potential applications, for example, laser, amplifier, and LRSPP discussed.

  4. Advanced unrepeatered systems using novel Raman amplification schemes

    Science.gov (United States)

    Chang, Do-il; Pelouch, Wayne; Burtsev, Sergey; Perrier, Philippe; Fevrier, Herve

    2015-01-01

    Unrepeatered transmission systems provide a cost-effective solution to transmit high capacity channels in submarine networks to communicate between coastal population centers or in terrestrial networks to connect remote areas where service access is difficult. The main goal of unrepeatered systems has traditionally been to achieve the longest reach, however, increasing traffic demands now require unrepeatered systems to support both longer reach and higher transport capacity. As a result, transmission rate of unrepeatered systems has quickly moved from 10 Gb/s to 40 Gb/s or 100 Gb/s. This paper reviews the key basic technologies, with a specific focus on Raman amplification, required for long-reach, high-capacity unrepeatered optical transmission systems. We will discuss novel Raman amplification schemes, enhanced remote optically pumped amplifiers (ROPA), ultra-low loss / large effective area fibers, and coherent transmission with advanced modulation format and high FEC coding gain. We will also report recent experimental demonstrations that show how these technologies have been combined to achieve industry's leading capacity and reach transmission.

  5. Solid phase DNA extraction on PDMS and direct amplification.

    Science.gov (United States)

    Pasquardini, Laura; Potrich, Cristina; Quaglio, Marzia; Lamberti, Andrea; Guastella, Salvatore; Lunelli, Lorenzo; Cocuzza, Matteo; Vanzetti, Lia; Pirri, Candido Fabrizio; Pederzolli, Cecilia

    2011-12-07

    In this paper we report an innovative use of Poly(DiMethyl)Siloxane (PDMS) to design a microfluidic device that combines, for the first time, in one single reaction chamber, DNA purification from a complex biological sample (blood) without elution and PCR without surface passivation agents. This result is achieved by exploiting the spontaneous chemical structure and nanomorphology of the material after casting. The observed surface organization leads to spontaneous DNA adsorption. This property allows on-chip complete protocols of purification of complex biological samples to be performed directly, starting from cells lysis. Amplification by PCR is performed directly on the adsorbed DNA, avoiding the elution process that is normally required by DNA purification protocols. The use of one single microfluidic volume for both DNA purification and amplification dramatically simplifies the structure of microfluidic devices for DNA preparation. X-Ray Photoelectron Spectroscopy (XPS) was used to analyze the surface chemical composition. Atomic Force Microscopy (AFM) and Field Emission Scanning Electron Microscopy (FESEM) were employed to assess the morphological nanostructure of the PDMS-chips. A confocal fluorescence analysis was utilized to check DNA distribution inside the chip.

  6. Amplification of Mitochondrial DNA for detection of Plasmodiumvivax in Balochistan.

    Science.gov (United States)

    Shahwani, Muhammad Naeem; Nisar, Samia; Aleem, Abdul; Panezai, Marina; Afridi, Sarwat; Malik, Shaukat Iqbal

    2017-05-01

    To access a new step using PCR to amplify the targeted mtDNA sequence for detecting specifically Plasmodium vivax and its co-infections, false positive and false negative results with Plasmodium falciparum. In this study we have standardized a new technical approach in which the target mitochondrial DNA sequence (mtDNA) was amplified by using a PCR technique as a tool to detect Plasmodium spp. Species specific primers were designed to hybridize with cytochrome c oxidase gene of P. vivax (cox I) and P. falciparum (cox III). Two hundred blood samples were collected on the basis of clinical symptoms which were initially examined through microscopic analysis after preparing Giemsa stained thick and thin blood smears. Afterwards genomic DNA was extracted from all samples and was then subjected to PCR amplification by using species specific primers and amplified segments were sequenced for confirmation of results. One-hundred and thirty-two blood samples were detected as positive for malaria by PCR, out of which 64 were found to be positive by PCR and 53 by both microscopy and PCR for P.vivax infection. Nine samples were found to be false negative, one P.vivax mono infection was declared as co infection by PCR and 3 samples identified as having P.falciparum gametes were confirmed as P.vivax by PCR amplification. Sensitivity and specificity were found to be 85% and 92% respectively. Results obtained through PCR method were comparatively better and reliable than microscopy.

  7. Static and Dynamic Amplification Using Strong Mechanical Coupling

    KAUST Repository

    Ilyas, Saad

    2016-07-28

    Amplifying the signal-to-noise ratio of resonant sensors is vital toward the effort to miniaturize devices into the sub-micro and nano regimes. In this paper, we demonstrate theoretically and experimentally, amplification through mechanically coupled microbeams. The device is composed of two identical clamped-clamped beams, made of polyimide, connected at their middle through a third beam, which acts as a mechanical coupler. Each of the clamped-clamped microbeams and the coupler are designed to be actuated separately, hence providing various possibilities of actuation and sensing. The coupled resonator is driven into resonance near its first resonance mode and its dynamic behavior is explored via frequency sweeps. The results show significant amplification in the resonator amplitude when the signal is measured at the midpoint of the coupler compared with the response of the individual uncoupled beams. The static pull-in characteristics of the resonator are also studied. It is shown that the compliant mechanical coupler can serve as a low-power radio frequency switch actuated at low voltage loads. [2016-0100

  8. Linkage mechanics and power amplification of the mantis shrimp's strike.

    Science.gov (United States)

    Patek, S N; Nowroozi, B N; Baio, J E; Caldwell, R L; Summers, A P

    2007-10-01

    Mantis shrimp (Stomatopoda) generate extremely rapid and forceful predatory strikes through a suite of structural modifications of their raptorial appendages. Here we examine the key morphological and kinematic components of the raptorial strike that amplify the power output of the underlying muscle contractions. Morphological analyses of joint mechanics are integrated with CT scans of mineralization patterns and kinematic analyses toward the goal of understanding the mechanical basis of linkage dynamics and strike performance. We test whether a four-bar linkage mechanism amplifies rotation in this system and find that the rotational amplification is approximately two times the input rotation, thereby amplifying the velocity and acceleration of the strike. The four-bar model is generally supported, although the observed kinematic transmission is lower than predicted by the four-bar model. The results of the morphological, kinematic and mechanical analyses suggest a multi-faceted mechanical system that integrates latches, linkages and lever arms and is powered by multiple sites of cuticular energy storage. Through reorganization of joint architecture and asymmetric distribution of mineralized cuticle, the mantis shrimp's raptorial appendage offers a remarkable example of how structural and mechanical modifications can yield power amplification sufficient to produce speeds and forces at the outer known limits of biological systems.

  9. Parametric dispersion and amplification of acoustohelicon waves in piezoelectric semiconductors

    Science.gov (United States)

    Neogi, A.; Ghosh, S.

    1991-01-01

    Assuming that the origin of the nonlinear interaction lies in the second-order optical susceptibility arising from the nonlinear induced current density and using the coupled-mode theory, the parametric dispersion and amplification of acoustohelicon waves is analytically investigated in a longitudinally magnetized piezoelectric semiconductor of noncentrosymmetric nature. The relevant experiments have not been reported. The threshold value of the pump electric field E0th and its corresponding excitation intensity is obtained. The longitudinal magnetic field decreases the required magnitude of E0th for the excitation of parametric amplification. The phenomenon of self-defocusing of the signal in the prevailing case is found to be a consequence of the negative dispersive characteristics exhibited by the acoustohelicon waves. Numerical analyses are performed for an InSb crystal at 77 K, duly irradiated by frequency-doubled pulsed 10.6-μm CO2 lasers. The parametric gain constant is observed to be maximum when the cyclotron frequency ωc attains the magnitude equal to that of ω0, the incident laser frequency (=1.78×1014 s-1 ).

  10. Gas sensor

    Science.gov (United States)

    Schmid, Andreas K.; Mascaraque, Arantzazu; Santos, Benito; de la Figuera, Juan

    2014-09-09

    A gas sensor is described which incorporates a sensor stack comprising a first film layer of a ferromagnetic material, a spacer layer, and a second film layer of the ferromagnetic material. The first film layer is fabricated so that it exhibits a dependence of its magnetic anisotropy direction on the presence of a gas, That is, the orientation of the easy axis of magnetization will flip from out-of-plane to in-plane when the gas to be detected is present in sufficient concentration. By monitoring the change in resistance of the sensor stack when the orientation of the first layer's magnetization changes, and correlating that change with temperature one can determine both the identity and relative concentration of the detected gas. In one embodiment the stack sensor comprises a top ferromagnetic layer two mono layers thick of cobalt deposited upon a spacer layer of ruthenium, which in turn has a second layer of cobalt disposed on its other side, this second cobalt layer in contact with a programmable heater chip.

  11. CDK4 amplification predicts recurrence of well-differentiated liposarcoma of the abdomen.

    Directory of Open Access Journals (Sweden)

    Sanghoon Lee

    Full Text Available The absence of CDK4 amplification in liposarcomas is associated with favorable prognosis. We aimed to identify the factors associated with tumor recurrence in patients with well-differentiated (WD and dedifferentiated (DD liposarcomas.From 2000 to 2010, surgical resections for 101 WD and DD liposarcomas were performed. Cases in which complete surgical resections with curative intent were carried out were selected. MDM2 and CDK4 gene amplification were analyzed by quantitative real-time polymerase chain reaction (Q-PCR.There were 31 WD and 17 DD liposarcomas. Locoregional recurrence was observed in 11 WD and 3 DD liposarcomas. WD liposarcomas showed better patient survival compared to DD liposarcomas (P<0.05. Q-PCR analysis of the liposarcomas revealed the presence of CDK4 amplification in 44 cases (91.7% and MDM2 amplification in 46 cases (95.8%. WD liposarcomas with recurrence after surgical resection had significantly higher levels of CDK4 amplification compared to those without recurrence (P = 0.041. High level of CDK4 amplification (cases with CDK4 amplification higher than the median 7.54 was associated with poor recurrence-free survival compared to low CDK4 amplification in both univariate (P = 0.012 and multivariate analyses (P = 0.020.Level of CDK4 amplification determined by Q-PCR was associated with the recurrence of WD liposarcomas after surgical resection.

  12. Entropy amplification from energy feedback in simulated galaxy groups and clusters

    CERN Document Server

    Borgani, S; Kay, S T; Ponman, T J; Springel, V; Tozzi, P; Voit, G M

    2005-01-01

    We use hydrodynamical simulations of galaxy clusters and groups to study the effect of pre-heating on the entropy structure of the ICM. Our simulations account for non-gravitational heating of the gas either by imposing a minimum entropy floor at redshift z=3, or by considering feedback by galactic winds powered by supernova (SN) energy. In the adiabatic simulations we find that the entropy is increased out to the external regions as a consequence of the transition from clumpy to smooth accretion induced by extra heating. This result is in line with the predictions of the semi-analytical model by Voit et al. However, the introduction of radiative cooling substantially reduces this entropy amplification effect. While galactic winds of increasing strength are effective in regulating star formation, they have a negligible effect on the entropy profile of cluster-sized halos. Only in models where the action of the winds is complemented with diffuse heating corresponding to a pre-collapse entropy do we find a siza...

  13. Experiments on the amplification of optical activity. [molecular chirality in earth biosphere

    Science.gov (United States)

    Blair, N. E.; Bonner, W. A.

    1980-01-01

    Chemical mechanisms for the amplification of small, abiotically produced enantiomeric excesses leading to the complete stereo specificity of all biochemical reactions observed in the present-day biosphere are investigated quantitatively. Partial copolymerization of a mixture of R- and S-leucine or R- and S-valine N-carboxy anhydrides containing a known excess of one enantiomer was induced and the enantiomeric composition of the resulting oligomer was analyzed by gas chromatography. It is found that the 50% polymerization of leucine mixtures having excesses of 8 to 70% of either enantiomer leads to a significant enhancement of the enantiomeric excess of the polymer, accompanied by a corresponding decrease in the enantiomeric excess of the unpolymerized residue. On the other hand, 25-50% polymerization of valine mixtures is observed to result in polymers showing a decreased enantiomeric excess relative to the starting mixture and corresponding increases in those of the residue. Results of the leucine polymerization are interpreted as supporting the theory of steric interactions between the monomer and the helical structure of the polymer leading to the enrichment of one enantiomer, and possible mechanisms for the reverse stereospecificity observed in valine are discussed.

  14. Magnetic field amplification during gravitational collapse - Influence of initial conditions on dynamo evolution and saturation

    CERN Document Server

    Sur, Sharanya; Schleicher, Dominik R G; Banerjee, Robi; Klessen, Ralf S

    2012-01-01

    We study the influence of initial conditions on the magnetic field amplification during the collapse of a magnetised gas cloud. We focus on the dependence of the growth and saturation level of the dynamo generated field on the turbulent properties of the collapsing cloud. In particular, we explore the effect of varying the initial strength and injection scale of turbulence and the initial uniform rotation of the collapsing magnetised cloud. In order to follow the evolution of the magnetic field in both the kinematic and the nonlinear regime, we choose an initial field strength of $\\simeq 1\\,\\mkG$ with the magnetic to kinetic energy ratio, $E_{\\rm m}/E_{\\rm k} \\sim 10^{-4}$. Both gravitational compression and the small-scale dynamo initially amplify the magnetic field. Further into the evolution, the dynamo-generated magnetic field saturates but the total magnetic field continues to grow because of compression. The saturation of the small-scale dynamo is marked by a change in the slope of $B/\\rho^{2/3}$ and by...

  15. Nonlinear wake amplification by an active medium in a cylindrical waveguide using a modulated trigger bunch

    Institute of Scientific and Technical Information of China (English)

    Zeev; Toroker; Miron; Voin; Levi; Schchter

    2014-01-01

    Cerenkov wake amplification can be used as an accelerating scheme,in which a trigger bunch of electrons propagating inside a cylindrical waveguide filled with an active medium generates an initial wake field.Due to the multiple reflections inside the waveguide,the wake may be amplified significantly more strongly than when propagating in a boundless medium.Sufficiently far away from the trigger bunch the wake,which travels with the same phase velocity as the bunch,reaches saturation and it can accelerate a second bunch of electrons trailing behind.For a CO2 gas mixture our numerical and analytical calculations indicate that a short saturation length and a high gradient can be achieved with a large waveguide radius filled with a high density of excited atoms and a trigger bunch that travels at a velocity slightly above the Cerenkov velocity.To obtain a stable level of saturated wake that will be suitable for particle acceleration,it is crucial to satisfy the single-mode resonance condition,which requires high accuracy in the waveguide radius and the ratio between the electron phase velocity and the Cerenkov velocity.For single-mode propagation our model indicates that it is feasible to obtain gradients as high as GV m-1 in a waveguide length of cm.

  16. Natural Gas Transport

    OpenAIRE

    Tomás Correa; Nelson Osorio

    2009-01-01

    This paper reviews the present and future on natural gas transportation options, from oil and gas fields to markets, including liquefied natural gas, gas pipeline, compressed natural gas, natural gas hydrates, and gas to liquids and the perspectives of using them in Colombia, since this is the main fuel alternative to supply the world in at least the next 50 years.

  17. Natural Gas Transport

    Directory of Open Access Journals (Sweden)

    Tomás Correa

    2009-06-01

    Full Text Available This paper reviews the present and future on natural gas transportation options, from oil and gas fields to markets, including liquefied natural gas, gas pipeline, compressed natural gas, natural gas hydrates, and gas to liquids and the perspectives of using them in Colombia, since this is the main fuel alternative to supply the world in at least the next 50 years.

  18. Comparison of nucleic acid sequence-based amplification and loop-mediated isothermal amplification for diagnosis of human African trypanosomiasis.

    Science.gov (United States)

    Mugasa, Claire M; Katiti, Diana; Boobo, Alex; Lubega, George W; Schallig, Henk D F H; Matovu, Enock

    2014-02-01

    Diagnosis of human African trypanosomiasis (HAT) using molecular tests should ideally achieve high sensitivity without compromising specificity. This study compared 2 simplified tests, nucleic acid sequence-based amplification (NASBA) combined with oligochromatography (OC) and loop-mediated isothermal amplification (LAMP), executed on 181 blood samples from 65 Trypanosoma brucei gambiense HAT patients, 86 controls, and 30 serological suspects from Uganda. Basing on the composite reference standard, the diagnostic sensitivity and specificity of NASBA were 93.9% (95% confidence interval [CI] = 84.9-98.3%) and 100% (95% CI = 94.9-100%), respectively. The same parameters for LAMP were 76.9% (95% CI = 64.8-86.5%) and 100% (95% CI = 91.6-100%), respectively. The level of agreement between LAMP and microscopy was good with a kappa (κ) value of 79.2% (95% CI = 69.4-88.9%), while that of NASBA-OC/microscopy was very good (κ value 94.6%; 95% CI = 89.3-99.8%). The sensitivity of NASBA-OC was significantly higher than that of LAMP (Z = 2.723; P = 0.007). These tests have potential application to HAT surveillance.

  19. Wood gas; Holz gibt Gas

    Energy Technology Data Exchange (ETDEWEB)

    Hilgers, Claudia

    2011-06-17

    Sixty years ago, wood gas was even used as a car fuel. Today, this ancient technology is experiencing a renaissance. Small cogeneration plants with wood gasifiers are ideal for renewable and decentral power supply concepts for tomorrow. Until then, there is much pioneering work to do until plants will be ready for serial production.

  20. Clinical characteristics and outcome of patients with neuroblastoma presenting genomic amplification of loci other than MYCN.

    Directory of Open Access Journals (Sweden)

    Anne Guimier

    Full Text Available BACKGROUND: Somatically acquired genomic alterations with MYCN amplification (MNA are key features of neuroblastoma (NB, the most common extra-cranial malignant tumour of childhood. Little is known about the frequency, clinical characteristics and outcome of NBs harbouring genomic amplification(s distinct from MYCN. METHODS: Genomic profiles of 1100 NBs from French centres studied by array-CGH were re-examined specifically to identify regional amplifications. Patients were included if amplifications distinct from the MYCN locus were seen. A subset of NBs treated at Institut Curie and harbouring MNA as determined by array-CGH without other amplification was also studied. Clinical and histology data were retrospectively collected. RESULTS: In total, 56 patients were included and categorised into 3 groups. Group 1 (n = 8 presented regional amplification(s without MNA. Locus 12q13-14 was a recurrent amplified region (4/8 cases. This group was heterogeneous in terms of INSS stages, primary localisations and histology, with atypical clinical features. Group 2 (n = 26 had MNA as well as other regional amplifications. These patients shared clinical features of those of a group of NBs MYCN amplified (Group 3, n = 22. Overall survival for group 1 was better than that of groups 2 and 3 (5 year OS: 87.5%±11% vs 34.9%±7%, log-rank p<0.05. CONCLUSION: NBs harbouring regional amplification(s without MNA are rare and seem to show atypical features in clinical presentation and genomic profile. Further high resolution genetic explorations are justified in this heterogeneous group, especially when considering these alterations as predictive markers for targeted therapy.

  1. Social Amplification of Risk and Crisis Communication Planing - Case Study

    Science.gov (United States)

    Stanciugelu, I.; Frunzaru, V.; Armas, I.; Duntzer, A.; Stan, S.

    2012-04-01

    Risk management has become a dominant concern of public policy and the ability of government to anticipate the strength and focus of public concerns remains weak. The Social Amplification of Risk Framework (SARF) was designed to assist in this endeavor. It aims to facilitate a greater understanding of the social processes that can mediate between a hazard event and its consequences. SARF identifies categories of mediator/moderator that intervene between risk event and its consequences and suggests a causal and temporal sequence in which they act. Information flows first through various sources and then channels, triggering social stations of amplification, initiating individual station of amplification and precipitating behavioral reactions. The International Risk Governance Council Framework is an interdisciplinary and multilevel approach, linking risk management and risk assessment sphere through communication. This study aims to identify categories of mediator/moderator that intervene between the risk event and its consequences, using a survey on earthquake risk perception addressing population of Bucharest city. Romania has a unique seismic profile in Europe, being the country with the biggest surface affected in case of a serious earthquake. Considering the development of the urban area that took place in the last two decades and the growing number of inhabitants, Bucharest is the largest city in Romania and is exposed to extensive damages in case of an earthquake. The sociological survey has been conducted in December 2009 on a representative sample of the Bucharest population aged 18 and over (N=1376) using one stage sampling design. We used a stratified sample method shearing the investigated populations in six layers according to the six sectors of Bucharest. The respondents were selected using random digit dialling method (RDD) and the questionnaires were administered by research staff with computer assisted telephone interviewing method (CATI). The

  2. Investigation of gas discharge impulse image intensifiers

    Energy Technology Data Exchange (ETDEWEB)

    Gushchin, E.M. E-mail: evgeni@phep.mephi.msk.su; Somov, S.V.; Timofeev, M.K

    1999-08-21

    The gas discharge impulse image intensifiers (GDIII) operated in the streamer mode are studied in this work. The GDIII has a resolution of 5-15 lines/cm and light amplification up to {approx}10{sup 10}. The possibility to design a single-electron GDIII for RICH-detectors is considered. For this purpose the emission of photoelectrons in He, Ne, Ar, Xe, CO{sub 2}, iC{sub 4}H{sub 10} and their mixtures in the 50-760 Torr pressure range have been investigated. The best working gas for the GDIII is Ne+({approx}0.1%)iC{sub 4}H{sub 10} mixture having an electron output factor up to 0.45.

  3. Investigation of gas discharge impulse image intensifiers

    CERN Document Server

    Gushchin, E M; Timofeev, M K

    1999-01-01

    The gas discharge impulse image intensifiers (GDIII) operated in the streamer mode are studied in this work. The GDIII has a resolution of 5-15 lines/cm and light amplification up to approx 10 sup 1 sup 0. The possibility to design a single-electron GDIII for RICH-detectors is considered. For this purpose the emission of photoelectrons in He, Ne, Ar, Xe, CO sub 2 , iC sub 4 H sub 1 sub 0 and their mixtures in the 50-760 Torr pressure range have been investigated. The best working gas for the GDIII is Ne+(approx 0.1%)iC sub 4 H sub 1 sub 0 mixture having an electron output factor up to 0.45.

  4. Volcanic gas

    Science.gov (United States)

    McGee, Kenneth A.; Gerlach, Terrance M.

    1995-01-01

    In Roman mythology, Vulcan, the god of fire, was said to have made tools and weapons for the other gods in his workshop at Olympus. Throughout history, volcanoes have frequently been identified with Vulcan and other mythological figures. Scientists now know that the “smoke" from volcanoes, once attributed by poets to be from Vulcan’s forge, is actually volcanic gas naturally released from both active and many inactive volcanoes. The molten rock, or magma, that lies beneath volcanoes and fuels eruptions, contains abundant gases that are released to the surface before, during, and after eruptions. These gases range from relatively benign low-temperature steam to thick hot clouds of choking sulfurous fume jetting from the earth. Water vapor is typically the most abundant volcanic gas, followed by carbon dioxide and sulfur dioxide. Other volcanic gases are hydrogen sulfide, hydrochloric acid, hydrogen, carbon monoxide, hydrofluoric acid, and other trace gases and volatile metals. The concentrations of these gas species can vary considerably from one volcano to the next.

  5. Strand Invasion Based Amplification (SIBA®: a novel isothermal DNA amplification technology demonstrating high specificity and sensitivity for a single molecule of target analyte.

    Directory of Open Access Journals (Sweden)

    Mark J Hoser

    Full Text Available Isothermal nucleic acid amplification technologies offer significant advantages over polymerase chain reaction (PCR in that they do not require thermal cycling or sophisticated laboratory equipment. However, non-target-dependent amplification has limited the sensitivity of isothermal technologies and complex probes are usually required to distinguish between non-specific and target-dependent amplification. Here, we report a novel isothermal nucleic acid amplification technology, Strand Invasion Based Amplification (SIBA. SIBA technology is resistant to non-specific amplification, is able to detect a single molecule of target analyte, and does not require target-specific probes. The technology relies on the recombinase-dependent insertion of an invasion oligonucleotide (IO into the double-stranded target nucleic acid. The duplex regions peripheral to the IO insertion site dissociate, thereby enabling target-specific primers to bind. A polymerase then extends the primers onto the target nucleic acid leading to exponential amplification of the target. The primers are not substrates for the recombinase and are, therefore unable to extend the target template in the absence of the IO. The inclusion of 2'-O-methyl RNA to the IO ensures that it is not extendible and that it does not take part in the extension of the target template. These characteristics ensure that the technology is resistant to non-specific amplification since primer dimers or mis-priming are unable to exponentially amplify. Consequently, SIBA is highly specific and able to distinguish closely-related species with single molecule sensitivity in the absence of complex probes or sophisticated laboratory equipment. Here, we describe this technology in detail and demonstrate its use for the detection of Salmonella.

  6. "Social Laser": Action Amplification by Stimulated Emission of Social Energy

    CERN Document Server

    Khrennikov, Andrei

    2015-01-01

    The problem of the "explanation" of recent social explosions, especially in the Middle East, but also in Southern Europe and the USA, have been debated actively in the social and political literature. We can mention the contributions of P. Mason, F. Fukuyama, E. Schmidt and J. Cohen, I. Krastev to this debate. We point out that the diversity of opinions and conclusions is really amazing. At the moment, there is no consistent and commonly acceptable theory of these phenomena. We present a model of social explosions based on a novel approach for the description of social processes, namely, the quantum-like approach. Here quantum theory is treated simply as an operational formalism - without any direct relation to physics. We explore the quantum-like laser model to describe the possibility of Action Amplification by Stimulated Emission of Social Energy (ASE).

  7. Rapid PCR amplification of DNA utilizing Coriolis effects.

    Science.gov (United States)

    Mårtensson, Gustaf; Skote, Martin; Malmqvist, Mats; Falk, Mats; Asp, Allan; Svanvik, Nicke; Johansson, Arne

    2006-08-01

    A novel polymerase chain reaction (PCR) method is presented that utilizes Coriolis and centrifugal effects, produced by rotation of the sample disc, in order to increase internal circulatory rates, and with them temperature homogenization and mixing speeds. A proof of concept has been presented by testing a rapid 45-cycle PCR DNA amplification protocol. During the repeated heating and cooling that constitutes a PCR process, the 100 microL samples were rotated at a speed equivalent to an effective acceleration of gravity of 7,000 g. A cycle time of 20.5 s gave a total process time of 15 min to complete the 45 cycles. A theoretical and numerical analysis of the resulting flow, which describes the increased mixing and temperature homogenization, is presented. The device gives excellent reaction speed efficiency, which is beneficial for rapid PCR.

  8. Multiplex amplification of large sets of human exons.

    Science.gov (United States)

    Porreca, Gregory J; Zhang, Kun; Li, Jin Billy; Xie, Bin; Austin, Derek; Vassallo, Sara L; LeProust, Emily M; Peck, Bill J; Emig, Christopher J; Dahl, Fredrik; Gao, Yuan; Church, George M; Shendure, Jay

    2007-11-01

    A new generation of technologies is poised to reduce DNA sequencing costs by several orders of magnitude. But our ability to fully leverage the power of these technologies is crippled by the absence of suitable 'front-end' methods for isolating complex subsets of a mammalian genome at a scale that matches the throughput at which these platforms will routinely operate. We show that targeting oligonucleotides released from programmable microarrays can be used to capture and amplify approximately 10,000 human exons in a single multiplex reaction. Additionally, we show integration of this protocol with ultra-high-throughput sequencing for targeted variation discovery. Although the multiplex capture reaction is highly specific, we found that nonuniform capture is a key issue that will need to be resolved by additional optimization. We anticipate that highly multiplexed methods for targeted amplification will enable the comprehensive resequencing of human exons at a fraction of the cost of whole-genome resequencing.

  9. Liposomes as signal amplification reagents for bioassays in microfluidic channels.

    Science.gov (United States)

    Locascio, Laurie E; Hong, Jennifer S; Gaitan, Michael

    2002-03-01

    Liposomes with encapsulated carboxyfluorescein were used in an affinity-based assay to provide signal amplification for small-volume fluorescence measurements. Microfluidic channels were fabricated by imprinting in a plastic substrate material, poly(ethylene terephthalate glycol) (PETG), using a silicon template imprinting tool. Streptavidin was linked to the surface through biotinylated-protein for effective immobilization with minimal nonspecific adsorption of the liposome reagent. Lipids derivatized with biotin were incorporated into the liposome membrane to make the liposomes reactive for affinity assays. Specific binding of the liposomes to microchannel walls, dependence of binding on incubation time, and nonspecific adsorption of the liposome reagent were evaluated. The results of a competitive assay employing liposomes in the microchannels are presented.

  10. Cognitive and affective matching effects in persuasion: an amplification perspective.

    Science.gov (United States)

    Clarkson, Joshua J; Tormala, Zakary L; Rucker, Derek D

    2011-11-01

    Past research suggests that cognitive and affective attitudes are more open to change toward cognitive and affective (i.e., matched) persuasive attacks, respectively. The present research investigates how attitude certainty influences this openness. Although an extensive literature suggests that certainty generally reduces an attitude's openness to change, the authors explore the possibility that certainty might increase an attitude's openness to change in the context of affective or cognitive appeals. Based on the recently proposed amplification hypothesis, the authors posit that high (vs. low) attitude certainty will boost the resistance of attitudes to mismatched attacks (e.g., affective attitudes attacked by cognitive messages) but boost the openness of attitudes to matched attacks (e.g., affective attitudes attacked by affective messages). Two experiments provide support for this hypothesis. Implications for increasing the openness of attitudes to both matched and mismatched attacks are discussed.

  11. Shock induced porous barrier flows, with underlying wall pressure amplification

    Science.gov (United States)

    Skews, B. W.; Bugarin, S.

    The flow field resulting from the impact of a shock wave on a variety of sheets of permeable material is studied. Earlier studies examined the flow through stationary sheets. It has, however, been found that if the sheet is placed a short distance in front of a surface, and can move under the shock loading, the pressure on the surface is amplified following shock impact, compared to the pressures that would be experienced with no covering. An important application to consider is the effect that textile clothing may have on a persons body when exposed to a blast environment. Single and multiple layers of a range of textiles have been tested. It was established that the heavier, more impermeable textiles such as Kevlar can amplify the shock wave pressure by as much as 400%. Experiments were also done with the textiles placed at an angle to the incoming shock wave and the mechanism for the amplification established through schlieren photography and pressure measurements.

  12. Gelation induced supramolecular chirality: chirality transfer, amplification and application.

    Science.gov (United States)

    Duan, Pengfei; Cao, Hai; Zhang, Li; Liu, Minghua

    2014-08-14

    Supramolecular chirality defines chirality at the supramolecular level, and is generated from the spatial arrangement of component molecules assembling through non-covalent interactions such as hydrogen bonding, van der Waals interactions, π-π stacking, hydrophobic interactions and so on. During the formation of low molecular weight gels (LMWGs), one kind of fascinating soft material, one frequently encounters the phenomenon of chirality as well as chiral nanostructures, either from chiral gelators or even achiral gelators. A view of gelation-induced supramolecular chirality will be very helpful to understand the self-assembly process of the gelator molecules as well as the chiral structures, the regulation of the chirality in the gels and the development of the "smart" chiral materials such as chiroptical devices, catalysts and chiral sensors. It necessitates fundamental understanding of chirality transfer and amplification in these supramolecular systems. In this review, recent progress in gelation-induced supramolecular chirality is discussed.

  13. Raman Amplification in WDM Optical Communication Systems: A System Perceptive

    Science.gov (United States)

    Raghuwanshi, Sanjeev Kumar; Srinivas, Talabattula

    2016-12-01

    Statistical study on stimulated Raman scattering (SRS) crosstalk has been done by many researchers while ignoring pulse walk-off effect due to analytically unsolvable nonlinear coupled equations. To our knowledge there is no treatise, which deals with pulse walk-off effect except statistically for few cases in case of wideband WDM Raman amplification systems. In this paper, we investigate the effect of group velocity dispersion induced crosstalk. We have tried to solve nonlinear coupled Raman gain equations for few channels by using the numerical technique called finite difference method. Finally we have provided results of the simulation for few cases. It is ever known that pulse walk-off effect (time-dependent effect) is responsible for transient effects hence the modeling has also done in this paper to simulate the effect of abrupt channel addition and removal response.

  14. Run-up amplification of transient long waves

    CERN Document Server

    Stefanakis, Themistoklis; Dutykh, Denys; Dias, Frédéric

    2013-01-01

    The extreme characteristics of long wave run-up are studied in this paper. First we give a brief overview of the existing theory which is mainly based on the hodograph transformation (Carrier & Greenspan, 1958). Then, using numerical simulations, we build on the work of Stefanakis et al. (2011) for an infinite sloping beach and we find that resonant run-up amplification of monochromatic waves is robust to spectral perturbations of the incoming wave and resonant regimes do exist for certain values of the frequency. In the setting of a finite beach attached to a constant depth region, resonance can only be observed when the incoming wavelength is larger than the distance from the undisturbed shoreline to the seaward boundary. Wavefront steepness is also found to play a role in wave run-up, with steeper waves reaching higher run-up values.

  15. Diffusive shock acceleration with magnetic field amplification and Alfvenic drift

    CERN Document Server

    Kang, Hyesung

    2012-01-01

    We explore how wave-particle interactions affect diffusive shock acceleration (DSA) at astrophysical shocks by performing time-dependent kinetic simulations, in which phenomenological models for magnetic field amplification (MFA), Alfvenic drift, thermal leakage injection, Bohm-like diffusion, and a free escape boundary are implemented. If the injection fraction of cosmic-ray (CR) particles is greater than 2x10^{-4}, for the shock parameters relevant for young supernova remnants, DSA is efficient enough to develop a significant shock precursor due to CR feedback, and magnetic field can be amplified up to a factor of 20 via CR streaming instability in the upstream region. If scattering centers drift with Alfven speed in the amplified magnetic field, the CR energy spectrum can be steepened significantly and the acceleration efficiency is reduced. Nonlinear DSA with self-consistent MFA and Alfvenic drift predicts that the postshock CR pressure saturates roughly at 10 % of the shock ram pressure for strong shocks...

  16. Detection of Entamoeba histolytica by Recombinase Polymerase Amplification

    Science.gov (United States)

    Nair, Gayatri; Rebolledo, Mauricio; White, A. Clinton; Crannell, Zachary; Richards-Kortum, R. Rebecca; Pinilla, A. Elizabeth; Ramírez, Juan David; López, M. Consuelo; Castellanos-Gonzalez, Alejandro

    2015-01-01

    Amebiasis is an important cause of diarrheal disease worldwide and has been associated with childhood malnutrition. Traditional microscopy approaches are neither sensitive nor specific for Entamoeba histolytica. Antigen assays are more specific, but many cases are missed unless tested by molecular methods. Although polymerase chain reaction (PCR) is effective, the need for sophisticated, expensive equipment, infrastructure, and trained personnel limits its usefulness, especially in the resource-limited, endemic areas. Here, we report development of a recombinase polymerase amplification (RPA) method to detect E. histolytica specifically. Using visual detection by lateral flow (LF), the test was highly sensitive and specific and could be performed without additional equipment. The availability of this inexpensive, sensitive, and field-applicable diagnostic test could facilitate rapid diagnosis and treatment of amebiasis in endemic regions. PMID:26123960

  17. Optimisation of geometrical ratchets for spin-current amplification

    Energy Technology Data Exchange (ETDEWEB)

    Abdullah, Ranjdar M. [Department of Electronics, University of York, Heslington, York YO10 5DD (United Kingdom); Vick, Andrew J. [Department of Electronics, University of York, Heslington, York YO10 5DD (United Kingdom); Department of Physics, University of York, York YO10 5DD (United Kingdom); Murphy, Benedict A. [Department of Physics, University of York, York YO10 5DD (United Kingdom); Hirohata, Atsufumi, E-mail: atsufumi.hirohata@york.ac.uk [Department of Electronics, University of York, Heslington, York YO10 5DD (United Kingdom); PRESTO, Japan Science and Technology Agency, Kawaguchi 332-0012 (Japan)

    2015-05-07

    A two-dimensional model is used to study the geometrical effects of a nonmagnetic (NM) nanowire upon a spin-polarised electron current in a lateral spin-valve structure. We found that the implemented ratchet shapes at the centre of the NM have a crucial effect on the diffusive rate for up- and down-spin electrons along the wire, which leads to the amplification of non-local spin-current signals. By using our simple model, the geometries have been optimised. The calculated spin-current signals are in good qualitative agreement with our recent experimental results [Abdullah et al., J. Phys. D: Appl. Phys. 47, 482001(FTC) (2014)]. Our model may be very useful to evaluate such a geometrical effect on spin-polarised electron transport.

  18. Cascaded Parametric Amplification for Highly Efficient Terahertz Generation

    CERN Document Server

    Ravi, Koustuban; Cirmi, Giovanni; Reichert, Fabian; Schimpf, Damian N; Muecke, Oliver D; Kaertner, Franz X

    2016-01-01

    A highly efficient, practical approach to high-energy terahertz (THz) generation based on spectrally cascaded optical parametric amplification (THz-COPA) is introduced. The THz wave initially generated by difference frequency generation between a strong narrowband optical pump and optical seed (0.1-10% of pump energy) kick-starts a repeated or cascaded energy down-conversion of pump photons. This helps to greatly surpass the quantum-defect efficiency and results in exponential growth of THz energy over crystal length. In cryogenically cooled periodically poled lithium niobate, energy conversion efficiencies >8% for 100 ps pulses are predicted. The calculations account for cascading effects, absorption, dispersion and laser-induced damage. Due to the coupled nonlinear interaction of multiple triplets of waves, THz-COPA exhibits physics distinct from conventional three-wave mixing parametric amplifiers. This in turn governs optimal phase-matching conditions, evolution of optical spectra as well as limitations o...

  19. Copy number change: evolving views on gene amplification.

    Science.gov (United States)

    Elliott, Kathryn T; Cuff, Laura E; Neidle, Ellen L

    2013-07-01

    The rapid pace of genomic sequence analysis is increasing the awareness of intrinsically dynamic genetic landscapes. Gene duplication and amplification (GDA) contribute to adaptation and evolution by allowing DNA regions to expand and contract in an accordion-like fashion. This process affects diverse aspects of bacterial infection, including antibiotic resistance and host-pathogen interactions. In this review, microbial GDA is discussed, primarily using recent bacterial examples that demonstrate medical and evolutionary consequences. Interplay between GDA and horizontal gene transfer further impact evolutionary trajectories. Complementing the discovery of gene duplication in clinical and environmental settings, experimental evolution provides a powerful method to document genetic change over time. New methods for GDA detection highlight both its importance and its potential application for genetic engineering, synthetic biology and biotechnology.

  20. Unity-Efficiency Parametric Down-Conversion via Amplitude Amplification

    Science.gov (United States)

    Niu, Murphy Yuezhen; Sanders, Barry C.; Wong, Franco N. C.; Shapiro, Jeffrey H.

    2017-03-01

    We propose an optical scheme, employing optical parametric down-converters interlaced with nonlinear sign gates (NSGs), that completely converts an n -photon Fock-state pump to n signal-idler photon pairs when the down-converters' crystal lengths are chosen appropriately. The proof of this assertion relies on amplitude amplification, analogous to that employed in Grover search, applied to the full quantum dynamics of single-mode parametric down-conversion. When we require that all Grover iterations use the same crystal, and account for potential experimental limitations on crystal-length precision, our optimized conversion efficiencies reach unity for 1 ≤n ≤5 , after which they decrease monotonically for n values up to 50, which is the upper limit of our numerical dynamics evaluations. Nevertheless, our conversion efficiencies remain higher than those for a conventional (no NSGs) down-converter.

  1. Organo-erbium systems for optical amplification at telecommunications wavelengths.

    Science.gov (United States)

    Ye, H Q; Li, Z; Peng, Y; Wang, C C; Li, T Y; Zheng, Y X; Sapelkin, A; Adamopoulos, G; Hernández, I; Wyatt, P B; Gillin, W P

    2014-04-01

    Modern telecommunications rely on the transmission and manipulation of optical signals. Optical amplification plays a vital part in this technology, as all components in a real telecommunications system produce some loss. The two main issues with present amplifiers, which rely on erbium ions in a glass matrix, are the difficulty in integration onto a single substrate and the need of high pump power densities to produce gain. Here we show a potential organic optical amplifier material that demonstrates population inversion when pumped from above using low-power visible light. This system is integrated into an organic light-emitting diode demonstrating that electrical pumping can be achieved. This opens the possibility of direct electrically driven optical amplifiers and optical circuits. Our results provide an alternative approach to producing low-cost integrated optics that is compatible with existing silicon photonics and a different route to an effective integrated optics technology.

  2. Detection of Entamoeba histolytica by Recombinase Polymerase Amplification.

    Science.gov (United States)

    Nair, Gayatri; Rebolledo, Mauricio; White, A Clinton; Crannell, Zachary; Richards-Kortum, R Rebecca; Pinilla, A Elizabeth; Ramírez, Juan David; López, M Consuelo; Castellanos-Gonzalez, Alejandro

    2015-09-01

    Amebiasis is an important cause of diarrheal disease worldwide and has been associated with childhood malnutrition. Traditional microscopy approaches are neither sensitive nor specific for Entamoeba histolytica. Antigen assays are more specific, but many cases are missed unless tested by molecular methods. Although polymerase chain reaction (PCR) is effective, the need for sophisticated, expensive equipment, infrastructure, and trained personnel limits its usefulness, especially in the resource-limited, endemic areas. Here, we report development of a recombinase polymerase amplification (RPA) method to detect E. histolytica specifically. Using visual detection by lateral flow (LF), the test was highly sensitive and specific and could be performed without additional equipment. The availability of this inexpensive, sensitive, and field-applicable diagnostic test could facilitate rapid diagnosis and treatment of amebiasis in endemic regions.

  3. Amplification and Re-Generation of LNA-Modified Libraries

    DEFF Research Database (Denmark)

    Doessing, Holger; Hansen, Lykke H.; Veedu, Rakesh N.

    2012-01-01

    Locked nucleic acids (LNA) confer high thermal stability and nuclease resistance to oligonucleotides. The discovery of polymerases that accept LNA triphosphates has led us to propose a scheme for the amplification and re-generation of LNA-containing oligonucleotide libraries. Such libraries could...... be used for in vitro selection of e.g., native LNA aptamers. We maintained an oligonucleotide library encoding 40 randomized positions with LNA ATP, GTP, CTP, and TTP for 7 rounds of ‘mock’ in vitro selection in the absence of a target and analyzed the sequence composition after rounds 1, 4 and 7. We...... observed a decrease in LNA-A content from 20.5% in round 1 to 6.6% in round 7. This decrease was accompanied by a substantial bias against successive LNA-As (poly-LNA adenosine tracts) and a relative over-representation of single LNA-As. Maintaining a library with LNA TTP yielded similar results. Together...

  4. Adaptive weak-value amplification with adjustable postselection

    Science.gov (United States)

    Li, Fei; Huang, Jingzheng; Zeng, Guihua

    2017-09-01

    Weak-value amplification (WVA) has recently become an important technique for parameter estimation, owing to its ability to enhance the signal-to-noise ratio by amplifying extremely small signals with proper postselection strategies. In this paper, we propose an adaptive WVA scheme to achieve the highest Fisher information when using an unbalanced pointer. Different from previous schemes, the adaptive WVA scheme is associated with a real-time update on the postselection states with the help of feedback information from the outcomes, and the "extremely small" condition set on the parameter of interest is relaxed. By applying this scheme to a time-delay measurement scenario, we show by numerical simulation that the precision achieved in our scheme is several times higher than the standard WVA scheme. Our result might open a path for improving the WVA technique in a more flexible and robust way.

  5. Integrated Microfluidic Nucleic Acid Isolation, Isothermal Amplification, and Amplicon Quantification

    Directory of Open Access Journals (Sweden)

    Michael G. Mauk

    2015-10-01

    Full Text Available Microfluidic components and systems for rapid (<60 min, low-cost, convenient, field-deployable sequence-specific nucleic acid-based amplification tests (NAATs are described. A microfluidic point-of-care (POC diagnostics test to quantify HIV viral load from blood samples serves as a representative and instructive example to discuss the technical issues and capabilities of “lab on a chip” NAAT devices. A portable, miniaturized POC NAAT with performance comparable to conventional PCR (polymerase-chain reaction-based tests in clinical laboratories can be realized with a disposable, palm-sized, plastic microfluidic chip in which: (1 nucleic acids (NAs are extracted from relatively large (~mL volume sample lysates using an embedded porous silica glass fiber or cellulose binding phase (“membrane” to capture sample NAs in a flow-through, filtration mode; (2 NAs captured on the membrane are isothermally (~65 °C amplified; (3 amplicon production is monitored by real-time fluorescence detection, such as with a smartphone CCD camera serving as a low-cost detector; and (4 paraffin-encapsulated, lyophilized reagents for temperature-activated release are pre-stored in the chip. Limits of Detection (LOD better than 103 virons/sample can be achieved. A modified chip with conduits hosting a diffusion-mode amplification process provides a simple visual indicator to readily quantify sample NA template. In addition, a companion microfluidic device for extracting plasma from whole blood without a centrifuge, generating cell-free plasma for chip-based molecular diagnostics, is described. Extensions to a myriad of related applications including, for example, food testing, cancer screening, and insect genotyping are briefly surveyed.

  6. Recombinase Polymerase Amplification Assay for Rapid Diagnostics of Dengue Infection.

    Directory of Open Access Journals (Sweden)

    Ahmed Abd El Wahed

    Full Text Available Over 2.5 billion people are exposed to the risk of contracting dengue fever (DF. Early diagnosis of DF helps to diminish its burden on public health. Real-time reverse transcription polymerase amplification assays (RT-PCR are the standard method for molecular detection of the dengue virus (DENV. Real-time RT-PCR analysis is not suitable for on-site screening since mobile devices are large, expensive, and complex. In this study, two RT-recombinase polymerase amplification (RT-RPA assays were developed to detect DENV1-4.Using two quantitative RNA molecular standards, the analytical sensitivity of a RT-RPA targeting the 3´non-translated region of DENV1-4 was found to range from 14 (DENV4 to 241 (DENV1-3 RNA molecules detected. The assay was specific and did not cross detect other Flaviviruses. The RT-RPA assay was tested in a mobile laboratory combining magnetic-bead based total nucleic acid extraction and a portable detection device in Kedougou (Senegal and in Bangkok (Thailand. In Kedougou, the RT-RPA was operated at an ambient temperature of 38 °C with auxiliary electricity tapped from a motor vehicle and yielded a clinical sensitivity and specificity of 98% (n=31 and 100% (n=23, respectively. While in the field trial in Bangkok, the clinical sensitivity and specificity were 72% (n=90 and 100%(n=41, respectively.During the first 5 days of infection, the developed DENV1-4 RT-RPA assays constitute a suitable accurate and rapid assay for DENV diagnosis. Moreover, the use of a portable fluorescence-reading device broadens its application potential to the point-of-care for outbreak investigations.

  7. Mechanism of chimera formation during the Multiple Displacement Amplification reaction

    Directory of Open Access Journals (Sweden)

    Stockwell Timothy B

    2007-04-01

    Full Text Available Abstract Background Multiple Displacement Amplification (MDA is a method used for amplifying limiting DNA sources. The high molecular weight amplified DNA is ideal for DNA library construction. While this has enabled genomic sequencing from one or a few cells of unculturable microorganisms, the process is complicated by the tendency of MDA to generate chimeric DNA rearrangements in the amplified DNA. Determining the source of the DNA rearrangements would be an important step towards reducing or eliminating them. Results Here, we characterize the major types of chimeras formed by carrying out an MDA whole genome amplification from a single E. coli cell and sequencing by the 454 Life Sciences method. Analysis of 475 chimeras revealed the predominant reaction mechanisms that create the DNA rearrangements. The highly branched DNA synthesized in MDA can assume many alternative secondary structures. DNA strands extended on an initial template can be displaced becoming available to prime on a second template creating the chimeras. Evidence supports a model in which branch migration can displace 3'-ends freeing them to prime on the new templates. More than 85% of the resulting DNA rearrangements were inverted sequences with intervening deletions that the model predicts. Intramolecular rearrangements were favored, with displaced 3'-ends reannealing to single stranded 5'-strands contained within the same branched DNA molecule. In over 70% of the chimeric junctions, the 3' termini had initiated priming at complimentary sequences of 2–21 nucleotides (nts in the new templates. Conclusion Formation of chimeras is an important limitation to the MDA method, particularly for whole genome sequencing. Identification of the mechanism for chimera formation provides new insight into the MDA reaction and suggests methods to reduce chimeras. The 454 sequencing approach used here will provide a rapid method to assess the utility of reaction modifications.

  8. Millijoule pulse energy picosecond fiber chirped-pulse amplification system

    Institute of Scientific and Technical Information of China (English)

    Zhi Yang; Xiaohong Hu; Yishan Wang; Wei Zhang; Wei Zhao

    2011-01-01

    @@ The efficient generation of a 1.17-mJ laser pul8e with 360 ps duration using an ytterbium (Yb)-doped fiber amplifier chain seeded by a homemade mode-locked fiber laser is demonstrated experimentally.A specially designed figure-of-eight fiber laser acts as the seed source of a chirped-pulse amplification (CPA) system and generates mode-locked pulse8 with hundreds of picosecond widths.Two kinds of large-mode-area (LMA) double-clad Yb-doped fibers are employed to construct the pre-amplifier and main amplifier, All of the adopted instruments help avoid severe nonlinearity in fibers to raise sub-nanosecond pulse energy with acceptable signal-to-noise ratio (SNR).The output spectrum of this fiber-based CPA system shows that amplified spontaneous emission (ASE) is suppressed to better than 30 dB, and the onset of stimulated Raman scattering is excluded.%The efficient generation of a 1.17-mJ laser pulse with 360 ps duration using an ytterbium (Yb)-doped fiber amplifier chain seeded by a homemade mode-locked fiber laser is demonstrated experimentally. A specially designed figure-of-eight fiber laser acts as the seed source of a chirped-pulse amplification (CPA) system and generates mode-locked pulses with hundreds of picosecond widths. Two kinds of large-mode-area (LMA) double-clad Yb-doped fibers are employed to construct the pre-amplifier and main amplifier. All of the adopted instruments help avoid severe nonlinearity in fibers to raise sub-nanosecond pulse energy with acceptable signal-to-noise ratio (SNR). The output spectrum of this fiber-based CPA system shows that amplified spontaneous emission (ASE) is suppressed to better than 30 dB, and the onset of stimulated Raman scattering is excluded.

  9. Turbulent amplification of magnetic fields in the laboratory

    Science.gov (United States)

    Gregori, Gianluca

    2014-10-01

    Magnetic fields exist ubiquitously in the Universe, as revealed by either diffuse radio-synchrotron emission, or Faraday rotation observations, with strengths from a few nG to tens of μG. The energy density of these fields is typically comparable to the energy density of the fluid motions of the plasma in which they are embedded, making magnetic fields essential players in the dynamics of the luminous matter in the Universe. At present, the origin and the distribution of the magnetic fields are far from being understood. The standard model for the origin of these intergalactic magnetic fields is through the amplification of seed fields via turbulent processes to the level consistent with current observations. We have conducted a series of laboratory experiments using high power laser facilities to exploit the scale invariance of the magneto-hydrodynamics equations. While the scaling is not perfect (e.g., in what concerns dissipation coefficients such as resistivity or viscosity), the similarity is sufficiently close to make such experiments interesting - and the results have been showing up the fundamental physical process at play. Our results indicate the magnetic field is indeed amplified by turbulent mechanisms. We relate our findings with processes occurring in supernova remnants and in cluster of galaxies. These experiments provide an example of magnetic field amplification by turbulence in plasmas, a physical process thought to occur in many astrophysical phenomena. The research leading to these results has received funding from the European Research Council under the European Community's Seventh Framework Programme (FP7/2007-2013)/ERC Grant Agreement No. 256973.

  10. Gene amplification of the Hps locus in Glycine max

    Directory of Open Access Journals (Sweden)

    Kuflu Kuflom

    2006-03-01

    Full Text Available Abstract Background Hydrophobic protein from soybean (HPS is an 8 kD cysteine-rich polypeptide that causes asthma in persons allergic to soybean dust. HPS is synthesized in the pod endocarp and deposited on the seed surface during development. Past evidence suggests that the protein may mediate the adherence or dehiscence of endocarp tissues during maturation and affect the lustre, or glossiness of the seed surface. Results A comparison of soybean germplasm by genomic DNA blot hybridization shows that the copy number and structure of the Hps locus is polymorphic among soybean cultivars and related species. Changes in Hps gene copy number were also detected by comparative genomic DNA hybridization using cDNA microarrays. The Hps copy number polymorphisms co-segregated with seed lustre phenotype and HPS surface protein in a cross between dull- and shiny-seeded soybeans. In soybean cultivar Harosoy 63, a minimum of 27 ± 5 copies of the Hps gene were estimated to be present in each haploid genome. The isolation and analysis of genomic clones indicates that the core Hps locus is comprised of a tandem array of reiterated units, with each 8.6 kb unit containing a single HPS open reading frame. Conclusion This study shows that polymorphisms at the Hps locus arise from changes in the gene copy number via gene amplification. We present a model whereby Hps copy number modulates protein expression levels and seed lustre, and we suggest that gene amplification may result from selection pressures imposed on crop plants.

  11. Multiplexed Recombinase Polymerase Amplification Assay To Detect Intestinal Protozoa.

    Science.gov (United States)

    Crannell, Zachary; Castellanos-Gonzalez, Alejandro; Nair, Gayatri; Mejia, Rojelio; White, A Clinton; Richards-Kortum, Rebecca

    2016-02-01

    This work describes a proof-of-concept multiplex recombinase polymerase amplification (RPA) assay with lateral flow readout that is capable of simultaneously detecting and differentiating DNA from any of the diarrhea-causing protozoa Giardia, Cryptosporidium, and Entamoeba. Together, these parasites contribute significantly to the global burden of diarrheal illness. Differential diagnosis of these parasites is traditionally accomplished via stool microscopy. However, microscopy is insensitive and can miss up to half of all cases. DNA-based diagnostics such as polymerase chain reaction (PCR) are far more sensitive; however, they rely on expensive thermal cycling equipment, limiting their availability to centralized reference laboratories. Isothermal DNA amplification platforms, such as the RPA platform used in this study, alleviate the need for thermal cycling equipment and have the potential to broaden access to more sensitive diagnostics. Until now, multiplex RPA assays have not been developed that are capable of simultaneously detecting and differentiating infections caused by different pathogens. We developed a multiplex RPA assay to detect the presence of DNA from Giardia, Cryptosporidium, and Entamoeba. The multiplex assay was characterized using synthetic DNA, where the limits-of-detection were calculated to be 403, 425, and 368 gene copies per reaction of the synthetic Giardia, Cryptosporidium, and Entamoeba targets, respectively (roughly 1.5 orders of magnitude higher than for the same targets in a singleplex RPA assay). The multiplex assay was also characterized using DNA extracted from live parasites spiked into stool samples where the limits-of-detection were calculated to be 444, 6, and 9 parasites per reaction for Giardia, Cryptosporidium, and Entamoeba parasites, respectively. This proof-of-concept assay may be reconfigured to detect a wide variety of targets by re-designing the primer and probe sequences.

  12. Amplification of effects of photons on wound healing

    Science.gov (United States)

    Dyson, Mary

    2009-02-01

    Following the absorption of photons by cells either resident in or in transit through the skin at and around a wound site, healing can be modulated. This is due to the primary, secondary and tertiary cellular effects of the photons. The main primary effect of phototherapy is photon absorption. This initiates secondary effects within the cells that have absorbed the photons. Secondary effects are restricted to cells that have absorbed a suprathreshold quantity of photonic energy. Photon absorption can lead to an increase in ATP synthesis and the release of reactive oxygen species that can activate specific transcription factors resulting in changes in synthesis of the enzymes needed for cellular proliferation, migration, phagocytosis and protein synthesis, all essential for wound healing. The amount of ATP production is limited in each cell by the availability of ADP and phosphate. Spatial and temporal amplification of the effects of photon absorption increases the range and duration of phototherapy. It may be caused in part by tertiary effects initiated in cells that have not absorbed photons by regulatory proteins such as cytokines secreted by cells that have absorbed photons. Amplification may also be due to changes induced by photons in immune cells, stem cells and soluble protein mediators while in transit through the dermal capillaries. The peripheral location of these capillaries makes their contents readily accessible to photons. The longer the duration of treatment, the greater will be the number of cells in transit that can be affected by photons. Depth of effect may be increased by transduction of electromagnetic energy into mechanical energy. For a treatment to be clinically effective on wound healing, its duration and power may each be important. Components of the immune system, endocrine system and nervous system may also amplify the effects of photons on wound healing.

  13. Post-Fragmentation Whole Genome Amplification-Based Method

    Science.gov (United States)

    Benardini, James; LaDuc, Myron T.; Langmore, John

    2011-01-01

    This innovation is derived from a proprietary amplification scheme that is based upon random fragmentation of the genome into a series of short, overlapping templates. The resulting shorter DNA strands (fragments with defined 3 and 5 termini. Specific primers to these termini are then used to isothermally amplify this library into potentially unlimited quantities that can be used immediately for multiple downstream applications including gel eletrophoresis, quantitative polymerase chain reaction (QPCR), comparative genomic hybridization microarray, SNP analysis, and sequencing. The standard reaction can be performed with minimal hands-on time, and can produce amplified DNA in as little as three hours. Post-fragmentation whole genome amplification-based technology provides a robust and accurate method of amplifying femtogram levels of starting material into microgram yields with no detectable allele bias. The amplified DNA also facilitates the preservation of samples (spacecraft samples) by amplifying scarce amounts of template DNA into microgram concentrations in just a few hours. Based on further optimization of this technology, this could be a feasible technology to use in sample preservation for potential future sample return missions. The research and technology development described here can be pivotal in dealing with backward/forward biological contamination from planetary missions. Such efforts rely heavily on an increasing understanding of the burden and diversity of microorganisms present on spacecraft surfaces throughout assembly and testing. The development and implementation of these technologies could significantly improve the comprehensiveness and resolving power of spacecraft-associated microbial population censuses, and are important to the continued evolution and advancement of planetary protection capabilities. Current molecular procedures for assaying spacecraft-associated microbial burden and diversity have inherent sample loss issues at

  14. Hybridization and amplification rate correction for affymetrix SNP arrays

    Directory of Open Access Journals (Sweden)

    Wang Quan

    2012-06-01

    Full Text Available Abstract Background Copy number variation (CNV is essential to understand the pathology of many complex diseases at the DNA level. Affymetrix SNP arrays, which are widely used for CNV studies, significantly depend on accurate copy number (CN estimation. Nevertheless, CN estimation may be biased by several factors, including cross-hybridization and training sample batch, as well as genomic waves of intensities induced by sequence-dependent hybridization rate and amplification efficiency. Since many available algorithms only address one or two of the three factors, a high false discovery rate (FDR often results when identifying CNV. Therefore, we have developed a new CNV detection pipeline which is based on hybridization and amplification rate correction (CNVhac. Methods CNVhac first estimates the allelic concentrations (ACs of target sequences by using the sample independent parameters trained through physicochemical hybridization law. Then the raw CN is estimated by taking the ratio of AC to the corresponding average AC from a reference sample set for one specific site. Finally, a hidden Markov model (HMM segmentation process is implemented to detect CNV regions. Results Based on public HapMap data, the results show that CNVhac effectively smoothes the genomic waves and facilitates more accurate raw CN estimates compared to other methods. Moreover, CNVhac alleviates, to a certain extent, the sample dependence of inference and makes CNV calling with appreciable low FDRs. Conclusion CNVhac is an effective approach to address the common difficulties in SNP array analysis, and the working principles of CNVhac can be easily extended to other platforms.

  15. Polymorphic microsatellites developed by cross-species amplifications in common pheasant breeds

    NARCIS (Netherlands)

    Baratti, M.; Alberti, A.; Groenen, M.A.M.; Veenendaal, T.; Fulgheri, F.D.

    2001-01-01

    Genetic variability was analysed in two common breeds of pheasant (Phasianus colchicus L. 1758) by means of cross-species amplifications of microsatellite loci: 154 chicken, Gallus gallus and 32 turkey, Meleagris gallopavo, primers were tested for amplification of pheasant DNA. Thirty-six primers (2

  16. Macroscale mechanical domain parametric amplification: superthreshold pumping and optimal excitation parameters

    DEFF Research Database (Denmark)

    Neumeyer, Stefan; Thomsen, Jon Juel

    2012-01-01

    amplification is possible for the second vibration mode, that the detuned case is phase lag insensitive, and that superthreshold pumping changes the gain/phase lag relationship, the phase lag range for which amplification and attenuation is realized, the optimum phase lag, and the attainable gain....

  17. Comparison of variations detection between whole-genome amplification methods used in single-cell resequencing

    DEFF Research Database (Denmark)

    Hou, Yong; Wu, Kui; Shi, Xulian;

    2015-01-01

    BACKGROUND: Single-cell resequencing (SCRS) provides many biomedical advances in variations detection at the single-cell level, but it currently relies on whole genome amplification (WGA). Three methods are commonly used for WGA: multiple displacement amplification (MDA), degenerate-oligonucleoti...

  18. Amplification of realistic Schrödinger-cat-state-like states by homodyne heralding

    DEFF Research Database (Denmark)

    Laghaout, Amine; Neergaard-Nielsen, Jonas S.; Rigas, Ioannes

    2013-01-01

    We present a scheme for the amplification of Schrödinger cat states that collapses two smaller states onto their constructive interference via a homodyne projection. We analyze the performance of the amplification in terms of fidelity and success rate when the input consists of either exact...

  19. The Media and Genetically Modified Foods : Evidence in Support of Social Amplification of Risk

    NARCIS (Netherlands)

    Frewer, L.J.; Miles, S.; Marsh, R.

    2002-01-01

    Empirical examinations of the "social amplification of risk" framework are rare, partly because of the difficulties in predicting when conditions likely to result in amplification effects will occur. This means that it is difficult to examine changes in risk perception that are contemporaneous with

  20. No fitness cost of glyphosate resistance endowed by massive EPSPS gene amplification in Amaranthus palmeri.

    Science.gov (United States)

    Vila-Aiub, Martin M; Goh, Sou S; Gaines, Todd A; Han, Heping; Busi, Roberto; Yu, Qin; Powles, Stephen B

    2014-04-01

    Amplification of the EPSPS gene has been previously identified as the glyphosate resistance mechanism in many populations of Amaranthus palmeri, a major weed pest in US agriculture. Here, we evaluate the effects of EPSPS gene amplification on both the level of glyphosate resistance and fitness cost of resistance. A. palmeri individuals resistant to glyphosate by expressing a wide range of EPSPS gene copy numbers were evaluated under competitive conditions in the presence or absence of glyphosate. Survival rates to glyphosate and fitness traits of plants under intra-specific competition were assessed. Plants with higher amplification of the EPSPS gene (53-fold) showed high levels of glyphosate resistance, whereas less amplification of the EPSPS gene (21-fold) endowed a lower level of glyphosate resistance. Without glyphosate but under competitive conditions, plants exhibiting up to 76-fold EPSPS gene amplification exhibited similar height, and biomass allocation to vegetative and reproductive organs, compared to glyphosate susceptible A. palmeri plants with no amplification of the EPSPS gene. Both the additive effects of EPSPS gene amplification on the level of glyphosate resistance and the lack of associated fitness costs are key factors contributing to EPSPS gene amplification as a widespread and important glyphosate resistance mechanism likely to become much more evident in weed plant species.

  1. A robust method for the amplification of RNA in the sense orientation

    Directory of Open Access Journals (Sweden)

    Quackenbush John

    2005-03-01

    Full Text Available Abstract Background Small quantities of RNA (1–4 μg total RNA available from biological samples frequently require a single round of amplification prior to analysis, but current amplification strategies have limitations that may restrict their usefulness in downstream genomic applications. The Eberwine amplification method has been extensively validated but is limited by its ability to produce only antisense RNA. Alternatives lack extensive validation and are often confounded by problems with bias or yield attributable to their greater biological and technical complexity. Results To overcome these limitations, we have developed a straightforward and robust protocol for amplification of RNA in the sense orientation. This protocol is based upon Eberwine's method but incorporates elements of more recent amplification techniques while avoiding their complexities. Our technique yields greater than 100-fold amplification, generates long transcript, and produces mRNA that is well suited for use with microarray applications. Microarrays performed with RNA amplified using this protocol demonstrate minimal amplification bias and high reproducibility. Conclusion The protocol we describe here is readily adaptable for the production of sense or antisense, labeled or unlabeled RNA from intact or partially-degraded prokaryotic or eukaryotic total RNA. The method outperforms several commercial RNA amplification kits and can be used in conjunction with a variety of microarray platforms, such as cDNA arrays, oligonucleotide arrays, and Affymetrix GeneChip™ arrays.

  2. Polymerase chain reaction amplification of genomic fragments of bovine herpesvirus-1

    OpenAIRE

    Cândido AL; ED Bontempo; Resende M.

    2000-01-01

    Especial conditions were developed for the amplification of five DNA segments from US region of BHV-1 by polymerase chain reaction. In order to eliminate most nonspecific products it was found that addition of three cosolvents DMSO, glycerol and NP 40 was a simple method for increasing the specificity of amplification.

  3. Two methods for increased specificity and sensitivity in loop-mediated isothermal amplification

    Science.gov (United States)

    The technique of loop-mediated isothermal amplification (LAMP) utilizes 4 (or 6) primers targeting 6 (or 8) regions within a fairly small segment of a genome for amplification, with concentration higher than that used in traditional PCR methods. The high concentrations of primers used leads to an in...

  4. Shortening distance of forward and reverse primers for nucleic acid isothermal amplification.

    Science.gov (United States)

    Haitao, Qu; Wenchao, Zhang; Xiaohui, Zhang; Xiujun, Wang; Sulong, Li

    2014-06-01

    Existent nucleic acid isothermal detection techniques for clinical diseases are difficult to promote greatly due to limitations in such aspects as methodology, costs of detection, amplification efficiency and conditions for operation. There is therefore an urgent need for a new isothermal amplification method with the characteristics of high accuracy, easy operation, short time of detection and low costs. We have devised a new method of nucleic acid isothermal amplification using Bst DNA polymerase under isothermal conditions (60-65°C). We call this method of amplification by shortening the distance between forward and reverse primers for nucleic acid isothermal amplification SDAMP. The results demonstrated that this technique is highly sensitive, specific and has short reaction times (40-60 min). Results of sequencing show that the products of SDAMP amplification are mainly polymers formed by series connection of monomers formed through linkage of forward primer and complementary sequences in reverse primer via a few bases. The method is different from current methods of nucleic acid amplification. Our study shows, however, that it is a specific method of nucleic acid isothermal amplification depending on interactions between primers and DNA template.

  5. The Media and Genetically Modified Foods : Evidence in Support of Social Amplification of Risk

    NARCIS (Netherlands)

    Frewer, L.J.; Miles, S.; Marsh, R.

    2002-01-01

    Empirical examinations of the "social amplification of risk" framework are rare, partly because of the difficulties in predicting when conditions likely to result in amplification effects will occur. This means that it is difficult to examine changes in risk perception that are contemporaneous with

  6. Plasma HER2 amplification in cell-free DNA during neoadjuvant chemotherapy in breast cancer

    DEFF Research Database (Denmark)

    Bechmann, Troels; Andersen, Rikke Fredslund; Pallisgaard, Niels

    2013-01-01

    Measurement of human epidermal growth factor receptor 2 (HER2) gene amplification in cell-free DNA (cfDNA) is an evolving technique in breast cancer, enabling liquid biopsies and treatment monitoring. The present study investigated the dynamics of plasma HER2 gene copy number and amplification in...... in cfDNA during neoadjuvant chemotherapy....

  7. Non-degenerate parametric amplification and filtering in biomimetic hair flow sensors

    NARCIS (Netherlands)

    Droogendijk, H.; Bruinink, C.M.; Sanders, R.G.P.; Krijnen, G.J.M.

    2011-01-01

    We report non-degenerate parametric amplification in our biomimetic MEMS hair-based flow-sensors with improved responsivity and sharp filtering through AC-biasing. To the best of our knowledge, this is the first flow sensor with tunable filtering by non-degenerate electromechanical parametric amplif

  8. Parametric amplification of matter waves in dipolar spinor Bose-Einstein condensates

    DEFF Research Database (Denmark)

    Deuretzbacher, F.; Gebreyesus, G.; Topic, O.;

    2010-01-01

    Spin-changing collisions may lead under proper conditions to the parametric amplification of matter waves in spinor Bose-Einstein condensates. Magnetic dipole-dipole interactions, although typically very weak in alkali-metal atoms, are shown to play a very relevant role in the amplification process...

  9. Simulation of Redox-Cycling Phenomena at Interdigitated Array (IDA) Electrodes: Amplification and Selectivity

    NARCIS (Netherlands)

    Odijk, M.; Olthuis, W.; Dam, T.V.A.; Berg, van den A.

    2008-01-01

    We present Finite Element Method (FEM) simulations of interdigitated array (IDA) electrode geometries to study and verify redox selectivity and redox cycling amplification factor. The simulations provide an adequate explanation of an earlier found, but poorly understood, high amplification factor (6

  10. Pulse train amplification and regeneration based on semiconductor quantum dots waveguide

    DEFF Research Database (Denmark)

    Chen, Yaohui; Öhman, Filip; Mørk, Jesper

    2008-01-01

    We numerical analyze pulse train amplification up to 200 Gbit/s in quantum dot amplifiers and present regeneration properties with saturable absorber based on semiconductor quantum dot waveguides.......We numerical analyze pulse train amplification up to 200 Gbit/s in quantum dot amplifiers and present regeneration properties with saturable absorber based on semiconductor quantum dot waveguides....

  11. MYEOV : A candidate gene for DNA amplification events occurring centromeric to CCNDI in breast cancer

    NARCIS (Netherlands)

    Janssen, JWG; Cuny, M; Orsetti, B; Rodriguez, C; Valles, H; Bartram, CR; Schuuring, E; Theillet, C

    2002-01-01

    Rearrangements of chromosome 11q13 are frequently observed in human cancer. The 11q13 region harbors several chromosomal breakpoint clusters found in hematologic malignancies and exhibits frequent DNA amplification in carcinomas. DNA amplification patterns in breast tumors are consistent with the ex

  12. Swing Amplification of Galactic Spiral Arms: Phase Synchronization of Stellar Epicycle Motion

    CERN Document Server

    Michikoshi, Shugo

    2016-01-01

    We revisit the swing amplification model of galactic spiral arms proposed by Toomre (1981). We describe the derivation of the perturbation equation in detail and investigate the amplification process of stellar spirals. We find that the elementary process of the swing amplification is the phase synchronization of the stellar epicycle motion. Regardless of the initial epicycle phase, the epicycle phases of stars in a spiral are synchronized during the amplification. Based on the phase synchronization, we explain the dependence of the pitch angle of spirals on the epicycle frequency. We find the most amplified spiral mode and calculate its pitch angle, wavelengths, and amplification factor, which are consistent with those obtained by the more rigorous model based on the Boltzmann equation by Julian and Toomre (1966).

  13. Isothermal amplification detection of nucleic acids by a double-nicked beacon.

    Science.gov (United States)

    Shi, Chao; Zhou, Meiling; Pan, Mei; Zhong, Guilin; Ma, Cuiping

    2016-03-01

    Isothermal and rapid amplification detection of nucleic acids is an important technology in environmental monitoring, foodborne pathogen detection, and point-of-care clinical diagnostics. Here we have developed a novel method of isothermal signal amplification for single-stranded DNA (ssDNA) detection. The ssDNA target could be used as an initiator, coupled with a double-nicked molecular beacon, to originate amplification cycles, achieving cascade signal amplification. In addition, the method showed good specificity and strong anti-jamming capability. Overall, it is a one-pot and isothermal strand displacement amplification method without the requirement of a stepwise procedure, which greatly simplifies the experimental procedure and decreases the probability of contamination of samples. With its advantages, the method would be very useful to detect nucleic acids in point-of-care or field use.

  14. Strategies for Amplification of Trinucleotide Repeats: Optimization of Fragile X and Androgen Receptor PCR.

    Science.gov (United States)

    Papp; Snyder; Sedra; Guida; Prior

    1996-06-01

    Background: Trinucleotide repeat regions are heritable unstable elements that change in copy number from generation to generation. Amplification of these triplet repeats is an important diagnostic tool for molecular medicine. However, these repeats are often difficult to amplify and may require the use of different cosolvents or amplification strategies. Methods and Results: We used the fragile X and androgen receptor triplet repeat regions to demonstrate a series of conditions that may be used to optimize the amplification of repeat sequences. Conclusions: For androgen receptor, we show that predigestion of the template DNA was sufficient to generate consistent amplification. In the case of fragile X we found that predigestion, when combined with use of betaine as a destabilizing additive, was superior to other methods and yielded consistent amplification of normal and premutation alleles in both isotopic and nonisotopic reactions.

  15. Coherent amplification of attosecond light pulses in the water-window spectral region.

    Science.gov (United States)

    Serrat, C; Roca, D; Seres, J

    2015-02-23

    We present a theoretical study on coherent extreme ultraviolet (XUV) attosecond pulse amplification mediated by nonlinear parametric enhanced forward scattering occurring in the interaction of a strong femtosecond infrared (IR) laser pulse combined with a weak attosecond XUV pulse train with an atom. We predict large amplification of XUV radiation when the IR strong pulse and the XUV weak pulse are optimally phased. We study high-order harmonic processes (HHG) in He, He(+) and Ne(++), and show how although the HHG yield is largely affected by the particular atom used as target, nonlinear parametric XUV amplification is only weakly affected. We conclude that XUV nonlinear parametric attosecond pulse amplification can be most efficiently observed by using atoms with a high ionization potential and that the nonlinear amplification is robust at high photon energies where HHG is not efficient, such as in the water-window spectral region.

  16. Amplification methods bias metagenomic libraries of uncultured single-stranded and double-stranded DNA viruses.

    Science.gov (United States)

    Kim, Kyoung-Ho; Bae, Jin-Woo

    2011-11-01

    Investigation of viruses in the environment often requires the amplification of viral DNA before sequencing of viral metagenomes. In this study, two of the most widely used amplification methods, the linker amplified shotgun library (LASL) and multiple displacement amplification (MDA) methods, were applied to a sample from the seawater surface. Viral DNA was extracted from viruses concentrated by tangential flow filtration and amplified by these two methods. 454 pyrosequencing was used to read the metagenomic sequences from different libraries. The resulting taxonomic classifications of the viruses, their functional assignments, and assembly patterns differed substantially depending on the amplification method. Only double-stranded DNA viruses were retrieved from the LASL, whereas most sequences in the MDA library were from single-stranded DNA viruses, and double-stranded DNA viral sequences were minorities. Thus, the two amplification methods reveal different aspects of viral diversity.

  17. Amplification and Compression of Ultrashort Fundamental Solitons in An Erbium-Doped Nonlinear Amplifying Fiber Loop Mirror

    Institute of Scientific and Technical Information of China (English)

    P.; K.; A.; Wai

    2003-01-01

    A nonlinear amplifying loop mirror constructed from erbium-doped fiber is proposed for simultaneous amplification and compression of ultrashort fundamental solitons. Numerical simulations show that, the proposed device performs efficient high-quality amplification and compression of solitons.

  18. Ultrasensitive detection of nucleic acids by template enhanced hybridization followed by rolling circle amplification and catalytic hairpin assembly.

    Science.gov (United States)

    Song, Weiling; Zhang, Qiao; Sun, Wenbo

    2015-02-11

    An ultrasensitive protocol for fluorescent detection of DNA is designed by combining the template enhanced hybridization process (TEHP) with Rolling Circle Amplification (RCA) and Catalytic Hairpin Assembly (CHA), showing a remarkable amplification efficiency.

  19. Sweet gas

    Science.gov (United States)

    Showstack, Randy

    When poisonous hydrogen sulfide contaminates a natural gas deposit, the drilling company usually caps the well and moves on to other areas that may contain larger reserves and offer stronger economic incentives. Chemical and biological methods exist to purify these wells, but most are complex and costly. However, a group of scientists now is developing what could be a cheaper, easier method to clean up and utilize this polluted natural gas.The technique—which involves growing “enrichment” cultures of bacteria that metabolize the hydrogen sulfide into harmless compounds—could be particularly useful to poor and energy-starved developing nations, says Norman Wainwright, a senior scientist at the Woods Hole Marine Biological Laboratory. “We're hoping the technique can be robust enough and inexpensive enough to be used in a developing country,” Wainwright says. Other scientists involved with the project are Porter Anderson, a University of Rochester professor emeritus associated with the lab and Ben Ebenhack, also of Rochester.

  20. 1.6 Micron Fiber Laser Source for CH4 Gas Leak Detection

    Directory of Open Access Journals (Sweden)

    Cézard Nicolas

    2016-01-01

    Full Text Available We report on the development of a new pulsed fiber laser source at 1645.5 nm, based on stimulated Raman amplification. This laser source is intended to be used in a future lidar system, dedicated to methane gas leak monitoring in the vicinity of industrial facilities. In this paper we discuss reasons for choosing the 1645.5 nm wavelength, and then we present the two-stage amplification architecture of our fiber laser source under development. Recent experimental results are provided and perspectives are drawn.

  1. Vorticity amplification near the stagnation point of landing gear wheels

    Science.gov (United States)

    Feltham, G.; Ekmekci, A.

    2014-04-01

    The vicinity near the forward stagnation point of landing-gear wheels has been found to support a mechanism for oncoming streams of weak vorticity to collect, grow, and amplify into discrete large-scale vortical structures that then shed with a distinct periodicity. To the authors' knowledge, such a flow phenomenon has never been reported before for landing gear wheels, which are in essence finite (three-dimensional) cylinders. To gain further insight into this phenomenon, a detailed experimental study has been undertaken employing the hydrogen bubble visualization and Particle Image Velocimetry techniques. A very thin platinum wire, similar to those used in hydrogen bubble visualization applications, was placed upstream of the wheel model to produce two streams of weak vorticity (with opposite sign) that convected toward the model. As the vorticity streams enter the stagnation region of the wheels, significant flow deceleration and vorticity stretching act to collect, grow, and amplify the incoming vorticity streams into large-scale vortical structures. Experiments were performed at a fixed Reynolds number, with a value of 32 500 when defined based on the diameter of the wheel and a value of 21 based on the diameter of the vorticity-generating upstream wire. First, to establish a baseline, the natural flow field (without the presence of an upstream wire) was characterized, where experimentally determined values for the stagnation boundary-layer thickness and the velocity profile along the stagnation streamline were both found to agree with the values provided in the literature for two-dimensional cylinders. Subsequently, the dynamics of vorticity collection, growth, amplification, and shedding were studied. The size, stand-off distance and the shedding frequency of the vortical structures forming near the stagnation region were all found to strongly depend on the impingement location of the inbound vorticity on the wheel. A simple relationship between the non

  2. Word Recognition and Learning: Effects of Hearing Loss and Amplification Feature

    Science.gov (United States)

    Stewart, Elizabeth C.; Willman, Amanda P.; Odgear, Ian S.

    2017-01-01

    Two amplification features were examined using auditory tasks that varied in stimulus familiarity. It was expected that the benefits of certain amplification features would increase as the familiarity with the stimuli decreased. A total of 20 children and 15 adults with normal hearing as well as 21 children and 17 adults with mild to severe hearing loss participated. Three models of ear-level devices were selected based on the quality of the high-frequency amplification or the digital noise reduction (DNR) they provided. The devices were fitted to each participant and used during testing only. Participants completed three tasks: (a) word recognition, (b) repetition and lexical decision of real and nonsense words, and (c) novel word learning. Performance improved significantly with amplification for both the children and the adults with hearing loss. Performance improved further with wideband amplification for the children more than for the adults. In steady-state noise and multitalker babble, performance decreased for both groups with little to no benefit from amplification or from the use of DNR. When compared with the listeners with normal hearing, significantly poorer performance was observed for both the children and adults with hearing loss on all tasks with few exceptions. Finally, analysis of across-task performance confirmed the hypothesis that benefit increased as the familiarity of the stimuli decreased for wideband amplification but not for DNR. However, users who prefer DNR for listening comfort are not likely to jeopardize their ability to detect and learn new information when using this feature.

  3. Primary extraskeletal osteosarcoma: a clinicopathological study of 18 cases focusing on MDM2 amplification status.

    Science.gov (United States)

    Yamashita, Kyoko; Kohashi, Kenichi; Yamada, Yuichi; Nishida, Yoshihiro; Urakawa, Hiroshi; Oda, Yoshinao; Toyokuni, Shinya

    2017-05-01

    Extraskeletal osteosarcoma (ESOS) is an uncommon malignant neoplasm. Most ESOSs are high grade, although some low-grade cases have been reported. A few cases of ESOS with MDM2 amplification have also been reported, suggesting some similarity to skeletal low-grade osteosarcoma such as parosteal osteosarcoma, where MDM2 is often amplified. However, the frequency of low-grade cases and cases with MDM2 amplification among ESOSs remains unknown, and their relationship is unclear. To clarify this, we examined 18 primary ESOS cases clinically, pathologically, and genetically, focusing on their MDM2 amplification status. Our cases comprised 10 men and 8 women whose mean age was 58.6 years; the most common site of the lesion was the thigh and buttock. There were one histologically low-grade case evaluated by biopsy specimen with an aggressive course and 2 relatively low-grade cases whose lesions were of low grade for the most part. MDM2 amplification status was revealed by fluorescence in situ hybridization in all 18 cases; 2 patients-histologically intermediate- and high-grade cases-were found to have MDM2 amplification. In conclusion, this study indicates that histologically low-grade and relatively low-grade cases of ESOS are not always associated with MDM2 amplification. The ESOS case with MDM2 amplification could be high grade, although MDM2-amplified dedifferentiated liposarcoma with osteogenic differentiation should be ruled out in making the diagnosis. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Isothermal Amplification Methods for the Detection of Nucleic Acids in Microfluidic Devices

    Directory of Open Access Journals (Sweden)

    Giuseppe Spoto

    2012-12-01

    Full Text Available Diagnostic tools for biomolecular detection need to fulfill specific requirements in terms of sensitivity, selectivity and high-throughput in order to widen their applicability and to minimize the cost of the assay. The nucleic acid amplification is a key step in DNA detection assays. It contributes to improving the assay sensitivity by enabling the detection of a limited number of target molecules. The use of microfluidic devices to miniaturize amplification protocols reduces the required sample volume and the analysis times and offers new possibilities for the process automation and integration in one single device. The vast majority of miniaturized systems for nucleic acid analysis exploit the polymerase chain reaction (PCR amplification method, which requires repeated cycles of three or two temperature-dependent steps during the amplification of the nucleic acid target sequence. In contrast, low temperature isothermal amplification methods have no need for thermal cycling thus requiring simplified microfluidic device features. Here, the use of miniaturized analysis systems using isothermal amplification reactions for the nucleic acid amplification will be discussed.

  5. Terminal Continuation (TC RNA Amplification Enables Expression Profiling Using Minute RNA Input Obtained from Mouse Brain

    Directory of Open Access Journals (Sweden)

    Stephen D. Ginsberg

    2008-10-01

    Full Text Available A novel methodology named terminal continuation (TC RNA amplification has been developed to amplify RNA from minute amounts of starting material. Utility of the TC RNA amplification method is demonstrated with two new modifications including obviating the need for second strand synthesis, and purifying the amplification template using column filtration prior to in vitro transcription (IVT. Using four low concentrations of RNA extracted from mouse brain (1, 10, 25 and 50 ng, one round TC RNA amplification was compared to one round amplified antisense RNA (aRNA in conjunction with column filtration and drop dialysis purification. The TC RNA amplification without second strand synthesis performed extremely well on customdesigned cDNA array platforms, and column filtration was found to provide higher positive detection of individual clones when hybridization signal intensity was subtracted from corresponding negative control hybridization signal levels. Results indicate that TC RNA amplification without second strand synthesis, in conjunction with column filtration, is an excellent method for RNA amplification from extremely small amounts of input RNA from mouse brain and postmortem human brain, and is compatible with microaspiration strategies and subsequent microarray analysis.

  6. Digital Droplet Multiple Displacement Amplification (ddMDA for Whole Genome Sequencing of Limited DNA Samples.

    Directory of Open Access Journals (Sweden)

    Minsoung Rhee

    Full Text Available Multiple displacement amplification (MDA is a widely used technique for amplification of DNA from samples containing limited amounts of DNA (e.g., uncultivable microbes or clinical samples before whole genome sequencing. Despite its advantages of high yield and fidelity, it suffers from high amplification bias and non-specific amplification when amplifying sub-nanogram of template DNA. Here, we present a microfluidic digital droplet MDA (ddMDA technique where partitioning of the template DNA into thousands of sub-nanoliter droplets, each containing a small number of DNA fragments, greatly reduces the competition among DNA fragments for primers and polymerase thereby greatly reducing amplification bias. Consequently, the ddMDA approach enabled a more uniform coverage of amplification over the entire length of the genome, with significantly lower bias and non-specific amplification than conventional MDA. For a sample containing 0.1 pg/μL of E. coli DNA (equivalent of ~3/1000 of an E. coli genome per droplet, ddMDA achieves a 65-fold increase in coverage in de novo assembly, and more than 20-fold increase in specificity (percentage of reads mapping to E. coli compared to the conventional tube MDA. ddMDA offers a powerful method useful for many applications including medical diagnostics, forensics, and environmental microbiology.

  7. The Study on Gene Amplification of EGFR in Bronchioloalveolar Carcinoma and Conventional Adenocarcinoma of the Lung

    Directory of Open Access Journals (Sweden)

    Xin SONG

    2009-08-01

    Full Text Available Background and objective Patients with adenocarcinoma of the lung have disproportionately response to the epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI. The aim of this study is to analyze the difference of EGFR gene amplification in bronchioloalveolar carcinoma (BAC, adenocarcinma mixed subtype and conventional adenocarcinoma of the lung and provide some information to clinical therapies. Methods Lung cancer cases were collected and reviewed from the archives of the Department of Pathology, Chinese PLA General Hospital during the time period from 2004 to 2006. The definite diagnosis of BAC based on 2004 WHO classification of lung tumors was made by two pathologists. Fluorescence in situ hybridization (FISH was performed to detect EGFR gene amplification in pure BAC, adenocarcinma mixed subtype and conventional adenocarcinoma. Results Conventional adenocarcinoma had higher EGFR amplification compared with pure BAC and adenocarcinma mixed subtype (χ2=11.632, P<0.05. EGFR gene amplification was found in 45.45% of conventional adenocarcinoma, 14.81% in pure BACs, and 22.58% in adenocarcinma mixed subtype. EGFR gene amplification was observed as scattered signals in most cases. Conclusion EGFR gene amplification was seen more frequently in the invasive components than in BAC. EGFR gene amplification might be associated with the development of adenocarcinoma of the lung.

  8. Isothermal amplification using a chemical heating device for point-of-care detection of HIV-1.

    Science.gov (United States)

    Curtis, Kelly A; Rudolph, Donna L; Nejad, Irene; Singleton, Jered; Beddoe, Andy; Weigl, Bernhard; LaBarre, Paul; Owen, S Michele

    2012-01-01

    To date, the use of traditional nucleic acid amplification tests (NAAT) for detection of HIV-1 DNA or RNA has been restricted to laboratory settings due to time, equipment, and technical expertise requirements. The availability of a rapid NAAT with applicability for resource-limited or point-of-care (POC) settings would fill a great need in HIV diagnostics, allowing for timely diagnosis or confirmation of infection status, as well as facilitating the diagnosis of acute infection, screening and evaluation of infants born to HIV-infected mothers. Isothermal amplification methods, such as reverse-transcription, loop-mediated isothermal amplification (RT-LAMP), exhibit characteristics that are ideal for POC settings, since they are typically quicker, easier to perform, and allow for integration into low-tech, portable heating devices. In this study, we evaluated the HIV-1 RT-LAMP assay using portable, non-instrumented nucleic acid amplification (NINA) heating devices that generate heat from the exothermic reaction of calcium oxide and water. The NINA heating devices exhibited stable temperatures throughout the amplification reaction and consistent amplification results between three separate devices and a thermalcycler. The performance of the NINA heaters was validated using whole blood specimens from HIV-1 infected patients. The RT-LAMP isothermal amplification method used in conjunction with a chemical heating device provides a portable, rapid and robust NAAT platform that has the potential to facilitate HIV-1 testing in resource-limited settings and POC.

  9. An evaluation of multiple annealing and looping based genome amplification using a synthetic bacterial community

    KAUST Repository

    Wang, Yong

    2016-02-23

    The low biomass in environmental samples is a major challenge for microbial metagenomic studies. The amplification of a genomic DNA was frequently applied to meeting the minimum requirement of the DNA for a high-throughput next-generation-sequencing technology. Using a synthetic bacterial community, the amplification efficiency of the Multiple Annealing and Looping Based Amplification Cycles (MALBAC) kit that is originally developed to amplify the single-cell genomic DNA of mammalian organisms is examined. The DNA template of 10 pg in each reaction of the MALBAC amplification may generate enough DNA for Illumina sequencing. Using 10 pg and 100 pg templates for each reaction set, the MALBAC kit shows a stable and homogeneous amplification as indicated by the highly consistent coverage of the reads from the two amplified samples on the contigs assembled by the original unamplified sample. Although GenomePlex whole genome amplification kit allows one to generate enough DNA using 100 pg of template in each reaction, the minority of the mixed bacterial species is not linearly amplified. For both of the kits, the GC-rich regions of the genomic DNA are not efficiently amplified as suggested by the low coverage of the contigs with the high GC content. The high efficiency of the MALBAC kit is supported for the amplification of environmental microbial DNA samples, and the concerns on its application are also raised to bacterial species with the high GC content.

  10. Basin amplification of seismic waves in the city of Pahrump, Nevada.

    Energy Technology Data Exchange (ETDEWEB)

    Abbott, Robert E.

    2005-07-01

    Sedimentary basins can increase the magnitude and extend the duration of seismic shaking. This potential for seismic amplification is investigated for Pahrump Valley, Nevada-California. The Pahrump Valley is located approximately 50 km northwest of Las Vegas and 75 km south of the Nevada Test Site. Gravity data suggest that the city of Pahrump sits atop a narrow, approximately 5 km deep sub-basin within the valley. The seismic amplification, or ''site effect'', was investigated using a combination of in situ velocity modeling and comparison of the waveforms and spectra of weak ground motion recorded in the city of Pahrump, Nevada, and those recorded in the nearby mountains. Resulting spectral ratios indicate seismic amplification factors of 3-6 over the deepest portion of Pahrump Valley. This amplification predominantly occurs at 2-2.5 Hz. Amplification over the deep sub-basin is lower than amplification at the sub-basin edge, location of the John Blume and Associates PAHA seismic station, which recorded many underground nuclear tests at the Nevada Test Site. A comprehensive analysis of basin amplification for the city of Pahrump should include 3-D basin modeling, due to the extreme basement topography of the Pahrump Valley.

  11. An evaluation of multiple annealing and looping based genome amplification using a synthetic bacterial community

    Institute of Scientific and Technical Information of China (English)

    WANG Yong; GAO Zhaoming; XU Ying; LI Guangyu; HE Lisheng; QIAN Peiyuan

    2016-01-01

    The low biomass in environmental samples is a major challenge for microbial metagenomic studies. The amplification of a genomic DNA was frequently applied to meeting the minimum requirement of the DNA for a high-throughput next-generation-sequencing technology. Using a synthetic bacterial community, the amplification efficiency of the Multiple Annealing and Looping Based Amplification Cycles (MALBAC) kit that is originally developed to amplify the single-cell genomic DNA of mammalian organisms is examined. The DNA template of 10 pg in each reaction of the MALBAC amplification may generate enough DNA for Illumina sequencing. Using 10 pg and 100 pg templates for each reaction set, the MALBAC kit shows a stable and homogeneous amplification as indicated by the highly consistent coverage of the reads from the two amplified samples on the contigs assembled by the original unamplified sample. Although GenomePlex whole genome amplification kit allows one to generate enough DNA using 100 pg of template in each reaction, the minority of the mixed bacterial species is not linearly amplified. For both of the kits, the GC-rich regions of the genomic DNA are not efficiently amplified as suggested by the low coverage of the contigs with the high GC content. The high efficiency of the MALBAC kit is supported for the amplification of environmental microbial DNA samples, and the concerns on its application are also raised to bacterial species with the high GC content.

  12. Amplified RNA degradation in T7-amplification methods results in biased microarray hybridizations

    Directory of Open Access Journals (Sweden)

    Ivell Richard

    2003-11-01

    Full Text Available Abstract Background The amplification of RNA with the T7-System is a widely used technique for obtaining increased amounts of RNA starting from limited material. The amplified RNA (aRNA can subsequently be used for microarray hybridizations, warranting sufficient signal for image analysis. We describe here an amplification-time dependent degradation of aRNA in prolonged standard T7 amplification protocols, that results in lower average size aRNA and decreased yields. Results A time-dependent degradation of amplified RNA (aRNA could be observed when using the classical "Eberwine" T7-Amplification method. When the amplification was conducted for more than 4 hours, the resulting aRNA showed a significantly smaller size distribution on gel electrophoresis and a concomitant reduction of aRNA yield. The degradation of aRNA could be correlated to the presence of the T7 RNA Polymerase in the amplification cocktail. The aRNA degradation resulted in a strong bias in microarray hybridizations with a high coefficient of variation and a significant reduction of signals of certain transcripts, that seem to be susceptible to this RNA degrading activity. The time-dependent degradation of these transcripts was verified by a real-time PCR approach. Conclusions It is important to perform amplifications not longer than 4 hours as there is a characteristic 'quality vs. yield' situation for longer amplification times. When conducting microarray hybridizations it is important not to compare results obtained with aRNA from different amplification times.

  13. Changes in southern hemispheric polar amplification over the past 5 million years revealed by climate modelling

    Science.gov (United States)

    Hoencamp, Jori; Stap, Lennert; Tuenter, Erik; Lourens, Luc; van de Wal, Roderik

    2016-04-01

    Knowledge on polar amplification is important to relate high latitude climate records to global mean temperature changes. Several studies have pointed out that the strength of polar amplification in the Northern Hemisphere varies considerably due to the presence of large ice sheets and more sea ice during colder climate conditions. As a result, the polar amplification in the Northern Hemisphere decreases for warmer climates. In this study, we address the fact that these changes in the Northern Hemisphere also affect the polar amplification in the Southern Hemisphere. We study the Southern and Northern Hemisphere amplification together over the past 5 million years with the CLIMBER-2 intermediate complexity model. Radiation, land ice extent and height, and greenhouse gases are prescribed as forcing. We find that in contrast to the reduction in polar amplification in the Northern Hemisphere, polar amplification in the Southern Hemisphere increases for warmer climates. The amplification decreases in the Northern Hemisphere from 2.7 during glacial conditions to 1.6 for a pre-industrial climate, which is line with other climate simulations. Over the same CO2 range the southern hemispheric polar amplification increases from 1 to 1.6. This is caused by the fact that the atmospheric transport needed to balance the radiation surplus in the equatorial region needs to be compensated by relatively stronger transport of energy in Southern direction while the transport in Northern direction reduces. This reduction in Northern direction is driven by less (land and sea) ice resulting in a smaller meridional gradient in Northern direction and hence a smaller atmospheric transport. As a consequence, the traditional scaled (with LGM temperature) Dome C record needs to be corrected with a maximum of 0.6 degrees half-way glacial and interglacial conditions, if it is to be interpreted as global mean temperature change indicator. While this changes the amplitude, the phasing of

  14. Human mitochondrial DNA complete amplification and sequencing: a new validated primer set that prevents nuclear DNA sequences of mitochondrial origin co-amplification.

    Science.gov (United States)

    Ramos, Amanda; Santos, Cristina; Alvarez, Luis; Nogués, Ramon; Aluja, Maria Pilar

    2009-05-01

    To date, there are no published primers to amplify the entire mitochondrial DNA (mtDNA) that completely prevent the amplification of nuclear DNA (nDNA) sequences of mitochondrial origin. The main goal of this work was to design, validate and describe a set of primers, to specifically amplify and sequence the complete human mtDNA, allowing the correct interpretation of mtDNA heteroplasmy in healthy and pathological samples. Validation was performed using two different approaches: (i) Basic Local Alignment Search Tool and (ii) amplification using isolated nDNA obtained from sperm cells by differential lyses. During the validation process, two mtDNA regions, with high similarity with nDNA, represent the major problematic areas for primer design. One of these could represent a non-published nuclear DNA sequence of mitochondrial origin. For two of the initially designed fragments, the amplification results reveal PCR artifacts that can be attributed to the poor quality of the DNA. After the validation, nine overlapping primer pairs to perform mtDNA amplification and 22 additional internal primers for mtDNA sequencing were obtained. These primers could be a useful tool in future projects that deal with mtDNA complete sequencing and heteroplasmy detection, since they represent a set of primers that have been tested for the non-amplification of nDNA.

  15. Amplification of surface acoustic waves by transverse electric current in piezoelectric semiconductors

    DEFF Research Database (Denmark)

    Gulyaev, Yuri V.

    1974-01-01

    It is shown that the principal characteristic feature of the surface acoustic waves in piezoelectrics—the presence of an alternating electric field transverse to the surface, which can be of the same order of magnitude as the longitudinal field—may not only give rise to the known transverse...... acoustoelectric effect but also lead to amplification of surface acoustic waves by electron drift perpendicular to the surface. For Love waves in a piezoelectric semiconductor film on a highly conducting substrate, the amplification coefficient is found and the conditions necessary for amplification...

  16. Dynamic Characteristics of a Hydraulic Amplification Mechanism for Large Displacement Actuators Systems

    Directory of Open Access Journals (Sweden)

    Xavier Arouette

    2010-03-01

    Full Text Available We have developed a hydraulic displacement amplification mechanism (HDAM and studied its dynamic response when combined with a piezoelectric actuator. The HDAM consists of an incompressible fluid sealed in a microcavity by two largely deformable polydimethylsiloxane (PDMS membranes. The geometry with input and output surfaces having different cross-sectional areas creates amplification. By combining the HDAM with micro-actuators, we can amplify the input displacement generated by the actuators, which is useful for applications requiring large deformation, such as tactile displays. We achieved a mechanism offering up to 18-fold displacement amplification for static actuation and 12-fold for 55 Hz dynamic actuation.

  17. Essential criteria for efficient pulse amplification via Raman and Brillouin scattering

    CERN Document Server

    Trines, R M G M; Webb, E; Vieira, J; Fiuza, F; Fonseca, R A; Silva, L O; Sadler, J; Ratan, N; Ceurvorst, L; Kasim, M F; Tabak, M; Froula, D; Haberberger, D; Norreys, P A; Cairns, R A; Bingham, R

    2016-01-01

    Raman and Brillouin amplification are two schemes for amplifying and compressing short laser pulses in plasma. Analytical models have already been derived for both schemes, but the full consequences of these models are little known or used. Here, we present new criteria that govern the evolution of the attractor solution for the seed pulse in Raman and Brillouin amplification, and show how the initial laser pulses need to be shaped to control the properties of the final amplified seed and improve the amplification efficiency.

  18. Copy Number Variation Analysis by Array Analysis of Single Cells Following Whole Genome Amplification.

    Science.gov (United States)

    Dimitriadou, Eftychia; Zamani Esteki, Masoud; Vermeesch, Joris Robert

    2015-01-01

    Whole genome amplification is required to ensure the availability of sufficient material for copy number variation analysis of a genome deriving from an individual cell. Here, we describe the protocols we use for copy number variation analysis of non-fixed single cells by array-based approaches following single-cell isolation and whole genome amplification. We are focusing on two alternative protocols, an isothermal and a PCR-based whole genome amplification method, followed by either comparative genome hybridization (aCGH) or SNP array analysis, respectively.

  19. Study on the protein expression and amplification of HER2 gene in gastric cancer

    Institute of Scientific and Technical Information of China (English)

    Sunan Wang; Yingying Li; Zhengshun Xu; Wenzhao Zhao; Tian Yun; Wuling Zhu; Yangkun Wang

    2014-01-01

    Objective:The aim of the study was to investigate the human epidermal growth factor receptor 2 (HER2) gene amplification and protein expression and interpretation points in the stomach mixed carcinomas. Methods:Immunohisto-chemistry (IHC) and fluorescence in situ hybridization (FISH) technique were used to detect HER2 gene amplification and ex-pression of HER2 protein in 442 cases of gastric mixed carcinoma. Results:The expression rate of HER2 protein was 41.2%(182/442):the HER2 protein expression IHC 3+extensive type in 18 cases, partial type in 21 cases, focal type in 8 cases, accounting for 10.6%(47/442);the HER2 protein expression IHC 2+extensive type in 23 cases, partial type in 28 cases, focal type in 11 cases, accounting for 14.0%(62/442);the HER2 protein expression IHC 1+extensive type in 27 cases, partial type in 31 cases, focal type in 15 cases, accounting for 16.5%(73/442). HER2 gene amplification rate of 442 cases was 16.1%(71/442). In 182 cases of HER2 protein positive expression, the HER2 gene cluster amplification rate was 14.8%(27/182), large granular amplification rate 11.0%(20/182), punctate amplification rate 6.0%(11/182) and high polysomy 7.1%(13/182). In 71 cases of HER2 gene amplification, there was 42 cases of HER2 protein expression IHC 3+, 22 cases of HER2 protein expression IHC 2+, and 7 cases of IHC 1+. Conclusion:HER2 detection of gastric mixed carcinoma has great heterogeneity, HER2 protein positive expression is divided into extensive type, partial type and focal type, and HER2 gene positive amplifica-tion is divided into cluster amplification, large granular amplification, punctate amplification and high polysomy. These typing of HER2 protein expression and HER2 gene amplification provide reference index to quantify for targeted therapeutic ef ect of anticancer drugs.

  20. Quantification of HER2 autoantibodies in the amplification phenomenon of HER2 in breast cancer

    DEFF Research Database (Denmark)

    Lauterlein, Jens-Jacob L; Petersen, Eva R B; Olsen, Dorte Aa

    2011-01-01

    Gene amplification of HER2 (human epidermal growth factor receptor 2) is a well-known phenomenon in various cancers. However, little is known about the mechanism of the gene amplification phenomenon itself. Autoantibodies to cellular receptors have been described in several cancer types. We hypot...... hypothesised that autoantibodies against HER2 might have a stimulatory capacity and could be the cause of the HER2 gene amplification phenomenon. To investigate this, we developed a test for the detection of autoantibodies against HER2 in serum (S-HER2Ab)....

  1. DMSO对PCR扩增反应的影响%The Influence of PCR Amplification with DMSO

    Institute of Scientific and Technical Information of China (English)

    徐葵; 邱志明; 汪晓英

    2001-01-01

    In Order to resolve the failure of PCR to amplif y 8-receptor, the influence of PCR amplification the different concentration of DMSO was observed. The result show that the centain concertation of DMSO can greatly enhance the specificity and efficiency of PCR amplification%为解决扩增δ-受体基因屡次失败的问题,观察了在 PCR体系加入不同浓度DMSO时对DNA扩增反应的影响.结果表明:一定浓度的DMSO可显著提高 PCR扩增的特异性和扩增效率.

  2. Amplification of LDH gene from Indian strains of Plasmodium vivax

    Directory of Open Access Journals (Sweden)

    Ritu Berwal, N. Gopalan, Kshitij Chandel, Shri Prakash ,K. Sekhar

    2006-09-01

    Full Text Available Background & objectives: Plasmodium vivax is geographically widespread and responsible for >50% of malaria cases in India. Increased drug resistance of the parasite highlights the immediaterequirement of early and accurate diagnosis as well as new therapeutics. In view of this, the presentstudy was undertaken to amplify P. vivax (Indian strains lactate dehydrogenase gene (PvLDHwhich has been identified as a good target for antimalarials as well as diagnostics.Methods: P. vivax infected clinical blood samples were collected from southern part of India andwere tested with established diagnostic parameters (ICT, Giemsa staining. Total DNA was extractedfrom blood samples and subjected to PCR using two sets of primers, one for the amplification of fullPvLDH gene (951bp and the other for a partial PvLDH gene fragment (422bp, covering a variableantigenic region (140aa as compared to other plasmodial species.Results & conclusion: PCRs for both the full and partial gene targets were optimised and found to beconsistent when tested on several P. vivax positive clinical samples. In addition, full gene PCR wasfound to specifically detect only P. vivax DNA and could be used as a specific molecular diagnostictool. These amplified products can be cloned and expressed as a recombinant protein that might beuseful for the development and screening of antimalarials as well as for diagnostic purposes.

  3. Using DNS amplification DDoS attack for hiding data

    Science.gov (United States)

    Mehić, M.; Voznak, M.; Safarik, J.; Partila, P.; Mikulec, M.

    2014-05-01

    This paper concerns available steganographic techniques that can be used for sending hidden data through public network. Typically, in steganographic communication it is advised to use popular/often used method for sending hidden data and amount of that data need to be high as much as possible. We confirmed this by choosing a Domain Name System (DNS) as a vital protocol of each network and choosing Distributed denial of service (DDoS) attacks that are most popular network attacks currently represented in the world. Apart from characterizing existing steganographic methods we provide new insights by presenting two new techniques. The first one is network steganography solution which exploits free/unused protocols fields and is known for IP, UDP or TCP protocols, but has never been applied to DNS (Domain Name Server) which are the fundamental part of network communications. The second explains the usage of DNS Amplification DDoS Attack to send seamlessly data through public network. The calculation that was performed to estimate the total amount of data that can be covertly transferred by using these technique, regardless of steganalysis, is included in this paper.

  4. Turbulent amplification of magnetic fields in colliding laboratory jets

    Science.gov (United States)

    Tzeferacos, P.; Meinecke, J.; Bell, A. R.; Doyle, H.; Bingham, R.; Churazov, E. M.; Crowston, R.; Murphy, C. D.; Woolsey, N. C.; Drake, R. P.; Kuranz, C. C.; MacDonald, M. J.; Wan, W. C.; Koenig, M.; Pelka, A.; Ravasio, A.; Yurchak, R.; Kuramitsu, Y.; Sakawa, Y.; Park, H.-S.; Reville, B.; Miniati, F.; Schekochihin, A. A.; Lamb, D. Q.; Gregori, G.

    2015-11-01

    Turbulence and magnetic fields are ubiquitous in the universe. In galaxy clusters, turbulence is believed to amplify seed magnetic fields to values of a few μG, as observed through diffuse radio-synchrotron emission and Faraday rotation measurements. In this study we present experiments that emulate such a process in a controlled laboratory environment. Two laser-driven plasma flows collide to mimic the dynamics of a cluster merger. From the measured density fluctuations we infer the development of Kolmogorov-like turbulence. Measurements of the magnetic field show it is amplified by turbulent motions, reaching a non-linear regime that is a precursor to turbulent dynamo. We also present numerical simulations with the FLASH code that model these experiments. The simulations reproduce the measured plasma properties and enable us to disentangle and characterize the complex physical processes that occur in the experiment. This study provides a promising experimental platform to probe magnetic field amplification by turbulence in plasmas, a process thought to occur in many astrophysical phenomena.

  5. Review:Whole genome amplification in preimplantation genetic diagnosis

    Institute of Scientific and Technical Information of China (English)

    Ying-ming ZHENG; Ning WANG; Lei LI; Fan JIN

    2011-01-01

    Preimplantation genetic diagnosis(PGD)refers to a procedure for genetically analyzing embryos prior to implantation,improving the chance of conception for patients at high risk of transmitting specific inherited disorders.This method has been widely used for a large number of genetic disorders since the first successful application in the early 1990s.Polymerase chain reaction(PCR)and fluorescent in situ hybridization(FISH)are the two main methods in PGD,but there are some inevitable shortcomings limiting the scope of genetic diagnosis.Fortunately,different whole genome amplification(WGA)techniques have been developed to overcome these problems.Sufficient DNA can be amplified and multiple tasks which need abundant DNA can be performed.Moreover,WGA products can be analyzed as a template for multi-loci and multi-gene during the subsequent DNA analysis.In this review,we will focus on the currently available WGA techniques and their applications,as well as the new technical trends from WGA products.

  6. Stochastic Amplification of Fluctuations in Cortical Up-States

    Science.gov (United States)

    Hidalgo, Jorge; Seoane, Luís F.; Cortés, Jesús M.; Muñoz, Miguel A.

    2012-01-01

    Cortical neurons are bistable; as a consequence their local field potentials can fluctuate between quiescent and active states, generating slow Hz oscillations which are widely known as transitions between Up and Down States. Despite a large number of studies on Up-Down transitions, deciphering its nature, mechanisms and function are still today challenging tasks. In this paper we focus on recent experimental evidence, showing that a class of spontaneous oscillations can emerge within the Up states. In particular, a non-trivial peak around Hz appears in their associated power-spectra, what produces an enhancement of the activity power for higher frequencies (in the Hz band). Moreover, this rhythm within Ups seems to be an emergent or collective phenomenon given that individual neurons do not lock to it as they remain mostly unsynchronized. Remarkably, similar oscillations (and the concomitant peak in the spectrum) do not appear in the Down states. Here we shed light on these findings by using different computational models for the dynamics of cortical networks in presence of different levels of physiological complexity. Our conclusion, supported by both theory and simulations, is that the collective phenomenon of “stochastic amplification of fluctuations” – previously described in other contexts such as Ecology and Epidemiology – explains in an elegant and parsimonious manner, beyond model-dependent details, this extra-rhythm emerging only in the Up states but not in the Downs. PMID:22879879

  7. Stochastic amplification of fluctuations in cortical up-states.

    Directory of Open Access Journals (Sweden)

    Jorge Hidalgo

    Full Text Available Cortical neurons are bistable; as a consequence their local field potentials can fluctuate between quiescent and active states, generating slow 0.5 2 Hz oscillations which are widely known as transitions between Up and Down States. Despite a large number of studies on Up-Down transitions, deciphering its nature, mechanisms and function are still today challenging tasks. In this paper we focus on recent experimental evidence, showing that a class of spontaneous oscillations can emerge within the Up states. In particular, a non-trivial peak around 20 Hz appears in their associated power-spectra, what produces an enhancement of the activity power for higher frequencies (in the 30-90 Hz band. Moreover, this rhythm within Ups seems to be an emergent or collective phenomenon given that individual neurons do not lock to it as they remain mostly unsynchronized. Remarkably, similar oscillations (and the concomitant peak in the spectrum do not appear in the Down states. Here we shed light on these findings by using different computational models for the dynamics of cortical networks in presence of different levels of physiological complexity. Our conclusion, supported by both theory and simulations, is that the collective phenomenon of "stochastic amplification of fluctuations"--previously described in other contexts such as Ecology and Epidemiology--explains in an elegant and parsimonious manner, beyond model-dependent details, this extra-rhythm emerging only in the Up states but not in the Downs.

  8. Hendra virus detection using Loop-Mediated Isothermal Amplification.

    Science.gov (United States)

    Foord, Adam J; Middleton, Deborah; Heine, Hans G

    2012-04-01

    Hendra virus (HeV) is a zoonotic paramyxovirus endemic in Australian Pteropus bats (fruit bats or flying foxes). Although bats appear to be unaffected by the virus, HeV can spread from fruit bats to horses, causing severe disease. Human infection results from close contact with the blood, body fluids and tissues of infected horses. HeV is a biosecurity level 4 (BSL-4) pathogen, with a high case-fatality rate in humans and horses. Current assays for HeV detection require complex instrumentation and are generally time consuming. The aim of this study was to develop a Loop-Mediated Isothermal Amplification (LAMP) assay to detect nucleic acid from all known HeV strains in horses without the requirement for complex laboratory equipment. A LAMP assay targeting a conserved region of the HeV P-gene was combined with a Lateral Flow Device (LFD) for detection of amplified product. All HeV isolates, the original HeV isolated in 1994 as well as the most recent isolates from 2011 were detected. Analytical sensitivity and specificity of the HeV-LAMP assay was equal to a TaqMan assay developed previously. Significantly, these assays detected HeV in horses before clinical signs were observed. The combined LAMP-LFD procedure is a sensitive method suitable for HeV diagnosis in a resource-limited situation or where rapid test results are critical.

  9. Magnetic field amplification during the common envelope phase

    Science.gov (United States)

    Ohlmann, Sebastian T.; Röpke, Friedrich K.; Pakmor, Rüdiger; Springel, Volker; Müller, Ewald

    2016-10-01

    During the common envelope (CE) phase, a giant star in a binary system overflows its Roche lobe and unstable mass transfer leads to a spiral-in of the companion, resulting in a close binary system or in a merger of the stellar cores. Dynamo processes during the CE phase have been proposed as a mechanism to generate magnetic fields that are important for forming magnetic white dwarfs (MWDs) and for shaping planetary nebulae. Here, we present the first magnetohydrodynamics simulations of the dynamical spiral-in during a CE phase. We find that magnetic fields are strongly amplified in the accretion stream around the 1 M⊙ companion as it spirals into the envelope of a 2 M⊙ RG. This leads to field strengths of 10-100 kG throughout the envelope after 120 d. The magnetic field amplification is consistent with being driven by the magnetorotational instability. The field strengths reached in our simulation make the magnetic field interesting for diagnostic purposes, but they are dynamically irrelevant. They are also too small to explain the formation of the highest fields found in MWDs, but may be relevant for luminous red novae, and detecting magnetic fields in these events would support the scenario as proposed here.

  10. Signal amplification in an agent-based herding model

    CERN Document Server

    Carro, Adrián; Miguel, Maxi San

    2013-01-01

    A growing part of the behavioral finance literature has addressed some of the stylized facts of financial time series as macroscopic patterns emerging from herding interactions among groups of agents with heterogeneous trading strategies and a limited rationality. We extend a stochastic herding formalism introduced for the modeling of decision making among financial agents, in order to take also into account an external influence. In particular, we study the amplification of an external signal imposed upon the agents by a mechanism of resonance. This signal can be interpreted as an advertising or a public perception in favor or against one of the two possible trading behaviors, thus periodically breaking the symmetry of the system and acting as a continuously varying exogenous shock. The conditions for the ensemble of agents to more accurately follow the periodicity of the signal are studied, finding a maximum in the response of the system for a given range of values of both the noise and the frequency of the...

  11. Current Developments in Prokaryotic Single Cell Whole Genome Amplification

    Energy Technology Data Exchange (ETDEWEB)

    Goudeau, Danielle; Nath, Nandita; Ciobanu, Doina; Cheng, Jan-Fang; Malmstrom, Rex

    2014-03-14

    Our approach to prokaryotic single-cell Whole Genome Amplification at the JGI continues to evolve. To increase both the quality and number of single-cell genomes produced, we explore all aspects of the process from cell sorting to sequencing. For example, we now utilize specialized reagents, acoustic liquid handling, and reduced reaction volumes eliminate non-target DNA contamination in WGA reactions. More specifically, we use a cleaner commercial WGA kit from Qiagen that employs a UV decontamination procedure initially developed at the JGI, and we use the Labcyte Echo for tip-less liquid transfer to set up 2uL reactions. Acoustic liquid handling also dramatically reduces reagent costs. In addition, we are exploring new cell lysis methods including treatment with Proteinase K, lysozyme, and other detergents, in order to complement standard alkaline lysis and allow for more efficient disruption of a wider range of cells. Incomplete lysis represents a major hurdle for WGA on some environmental samples, especially rhizosphere, peatland, and other soils. Finding effective lysis strategies that are also compatible with WGA is challenging, and we are currently assessing the impact of various strategies on genome recovery.

  12. Urban amplification of the global warming in Moscow megacity

    Science.gov (United States)

    Kislov, Alexander; Konstantinov, Pavel; Varentsov, Mikhail; Samsonov, Timofey; Gorlach, Irina; Trusilova, Kristina

    2015-04-01

    Climate changes in the large cities are very important and requires better understanding. The focus of this paper is climate change of the Moscow megacity. Its urban features strongly influence the atmospheric boundary layer above the Moscow agglomeration area and determine the microclimatic features of the local environment, such as urban heat island (UHI). Available meteorological observations within the Moscow urban area and surrounding territory allow us to assess the natural climate variations and human-induced climate warming separately. To obtain more precisely viewing on the UHI structure we have included into the analysis the satellite data (Meteosat-10), providing temperature and humidity profiles with high resolution. To investigate the mechanism of the urban amplification we realized the regional climate model COSMO-CLM+TEB. Apart from detailed climate research the model runs will be planned for climate projecting of Moscow agglomeration area. Climate change differences between urban and rural areas are determined by changes of the shape of the UHI and their relationships with changes of building height and density. Therefore, the urban module of COSMO-CLM+TEB model is fed by information from special GIS database contenting both geometric characteristics of the urban canyons and other characteristics of the urban surface. The sources of information were maps belonging to the OpenStreetMap, and digital elevation models SRTM90 and ASTER GDEM v.2 as well. The multiscale GIS database allows us to generate such kind of information with different spatial resolution (200, 500 and 1000 meters).

  13. Energy amplification in channel flows of viscoelastic fluids

    Science.gov (United States)

    Hoda, Nazish; Jovanovi?, Mihailo R.; Kumar, Satish

    Energy amplification in channel flows of Oldroyd-B fluids is studied from an input-output point of view by analysing the ensemble-average energy density associated with the velocity field of the linearized governing equations. The inputs consist of spatially distributed and temporally varying body forces that are harmonic in the streamwise and spanwise directions and stochastic in the wall-normal direction and in time. Such inputs enable the use of powerful tools from linear systems theory that have recently been applied to analyse Newtonian fluid flows. It is found that the energy density increases with a decrease in viscosity ratio (ratio of solvent viscosity to total viscosity) and an increase in Reynolds number and elasticity number. In most of the cases, streamwise-constant perturbations are most amplified and the location of maximum energy density shifts to higher spanwise wavenumbers with an increase in Reynolds number and elasticity number and a decrease in viscosity ratio. For similar parameter values, the maximum in the energy density occurs at a higher spanwise wavenumber for Poiseuille flow, whereas the maximum energy density achieves larger maxima for Couette flow. At low Reynolds numbers, the energy density decreases monotonically when the elasticity number is sufficiently small, but shows a maximum when the elasticity number becomes sufficiently large, suggesting that elasticity can amplify disturbances even when inertial effects are weak.

  14. Optical parametric amplification beyond the slowly varying amplitude approximation

    Indian Academy of Sciences (India)

    M Hosseini Farzad

    2007-09-01

    The coupled-wave equations describing optical parametric amplification (OPA) are usually solved in the slowly varying amplitude (SVA) approximation regime, in which the second-order derivatives of the signal and idler amplitudes are ignored and in fact the electromagnetic effects due to exit face of the medium is not involved. Here, an analytical plane-wave solution of these coupled-wave equations in a non-absorbing medium is presented. The solutions are derived beyond the SVA approximation up to order of = (coupling constant over the wave number). The intensity distributions of the signal and the idler waves show a periodic behavior about their corresponding distributions of SVA-adapted solution. This behavior can be explained by the interference of the forward propagating signal (idler) wave and the corresponding backward one resulted from the reflection by the end face of the medium. Furthermore, this interference pattern in the medium can in turn serve as a periodic source for the next generations of the signal and idler waves. Therefore, the superposition of the waves, generated from different points of this periodic source, at the exit face of the medium shows an oscillatory behavior of the transmitted signal (idler) wave in terms of normalized coupling constant, . This study also shows that this effect is more considerable for high intensity pump beam, high relative refractive index and short length of the nonlinear medium.

  15. NEW ERBIUM DOPED ANTIMONY GLASSES FOR LASER AND GLASS AMPLIFICATION

    Directory of Open Access Journals (Sweden)

    B. Tioua

    2015-07-01

    Full Text Available Because of the special spectroscopic properties of the rare earth ions, rare earth doped glasses are widely used in bulk and fiber lasers or amplifiers. The modelling of lasers and searching for new laser transitions require a precise knowledge of the spectroscopic properties of rare earth ions in different host glasses. In this poster will offer new doped erbium glasses synthesized in silicate crucibles were obtained in the combination Sb2O3-WO3-Na2O. Several properties are measured and correlated with glass compositions. The absorption spectral studies have been performed for erbium doped glasses. The intensities of various absorption bands of the doped glasses are measured and the Judd-Ofelt parameters have been computed. From the theory of Judd-Ofelt, various radiative properties, such as transition probability, branching ratio and radiative life time for various emission levels of these doped glasses have been determined and reported. These results confirm the ability of antimony glasses for glass amplification.

  16. A complete characterization of the heralded noiseless amplification of photons

    Science.gov (United States)

    Bruno, N.; Pini, V.; Martin, A.; Thew, R. T.

    2013-09-01

    Heralded noiseless amplification of photons has recently been shown to provide a means to overcome losses in complex quantum communication tasks. In particular, to overcome transmission losses that could allow for the violation of a Bell inequality free from the detection loophole, for device independent quantum key distribution (DI-QKD). Several implementations of a heralded photon amplifier have been proposed and the first proof of principle experiments realized. Here we present the first full characterization of such a device to test its functional limits and potential for DI-QKD. This device is tested at telecom wavelengths and is shown to be capable of overcoming losses corresponding to a transmission through 20 km of single mode telecom fibre. We demonstrate heralded photon amplifier with a gain >100 and a heralding probability >83%, required by DI-QKD protocols that use the Clauser-Horne-Shimony-Holt inequality. The heralded photon amplifier clearly represents a key technology for the realization of DI-QKD in the real world and over typical network distances.

  17. Towards rapid prototyped convective microfluidic DNA amplification platform

    Science.gov (United States)

    Ajit, Smrithi; Praveen, Hemanth Mithun; Puneeth, S. B.; Dave, Abhishek; Sesham, Bharat; Mohan, K. N.; Goel, Sanket

    2017-02-01

    Today, Polymerase Chain Reaction (PCR) based DNA amplification plays an indispensable role in the field of biomedical research. Its inherent ability to exponentially amplify sample DNA has proven useful for the identification of virulent pathogens like those causing Multiple Drug-Resistant Tuberculosis (MDR-TB). The intervention of Microfluidics technology has revolutionized the concept of PCR from being a laborious and time consuming process into one that is faster, easily portable and capable of being multifunctional. The Microfluidics based PCR outweighs its traditional counterpart in terms of flexibility of varying reaction rate, operation simplicity, need of a fraction of volume and capability of being integrated with other functional elements. The scope of the present work involves the development of a real-time continuous flow microfluidic device, fabricated by 3D printing-governed rapid prototyping method, eventually leading to an automated and robust platform to process multiple DNA samples for detection of MDRTB-associated mutations. The thermal gradient characteristic to the PCR process is produced using peltier units appropriate to the microfluidic environment fully monitored and controlled by a low cost controller driven by a Data Acquisition System. The process efficiency achieved in the microfluidic environment in terms of output per cycle is expected to be on par with the traditional PCR and capable of earning the additional advantages of being faster and minimizing the handling.

  18. Magnetic Field Amplification During the Common Envelope Phase

    CERN Document Server

    Ohlmann, Sebastian T; Pakmor, Ruediger; Springel, Volker; Mueller, Ewald

    2016-01-01

    During the common envelope (CE) phase, a giant star in a binary system overflows its Roche lobe and unstable mass transfer leads to a spiral-in of the companion, resulting in a close binary system or in a merger of the stellar cores. Dynamo processes during the CE phase have been proposed as a mechanism to generate magnetic fields that are important for forming magnetic white dwarfs (MWDs) and for shaping planetary nebulae. Here, we present the first magnetohydrodynamics simulations of the dynamical spiral-in during a CE phase. We find that magnetic fields are strongly amplified in the accretion stream around the $1M_\\odot$ companion as it spirals into the envelope of a $2M_\\odot$ RG. This leads to field strengths of 10 to 100 kG throughout the envelope after 120 d. The magnetic field amplification is consistent with being driven by the magnetorotational instability. The field strengths reached in our simulation make the magnetic field interesting for diagnostic purposes, but they are dynamically irrelevant. ...

  19. Amplification and Re-Generation of LNA-Modified Libraries

    Directory of Open Access Journals (Sweden)

    Jesper Wengel

    2012-11-01

    Full Text Available Locked nucleic acids (LNA confer high thermal stability and nuclease resistance to oligonucleotides. The discovery of polymerases that accept LNA triphosphates has led us to propose a scheme for the amplification and re-generation of LNA-containing oligonucleotide libraries. Such libraries could be used for in vitro selection of e.g., native LNA aptamers. We maintained an oligonucleotide library encoding 40 randomized positions with LNA ATP, GTP, CTP, and TTP for 7 rounds of ‘mock’ in vitro selection in the absence of a target and analyzed the sequence composition after rounds 1, 4 and 7. We observed a decrease in LNA-A content from 20.5% in round 1 to 6.6% in round 7. This decrease was accompanied by a substantial bias against successive LNA-As (poly-LNA adenosine tracts and a relative over-representation of single LNA-As. Maintaining a library with LNA TTP yielded similar results. Together, these results suggest that dispersed LNA monomers are tolerated in our in vitro selection protocol, and that LNA-modified libraries can be sustained for up to at least seven selection rounds, albeit at reduced levels. This enables the discovery of native LNA aptamers and similar oligonucleotide structures.

  20. Use of Peltier effect for small signal amplification and conversion

    Science.gov (United States)

    Ageyev, Y. I.; Akperov, M. M.; Kobakhidze, K. Z.; Nebuchinov, M. V.

    1984-04-01

    It is possible to use thermocouples operating as heat pumps with small temperature gradients to effect the control of elements whose properties are temperature dependent. This enables the construction of a number of electrical and optical signal transducers. The cooling or heating gain of a thermocouple used as a heat pump is proportional to the ratio of the cold or hot junction temperature to the temperature drop across the thermocouple. As this temperature gradient becomes quite small, the efficiency of such converters theoretically rises without limit. Under these conditions, the thermocouple can control any device whose properties change sharply in a narrow temperature range. Simple circuits for small signal amplification, frequency conversion, and detection were discussed. The gain of one such amplifier was plotted as a function of the input signal using various metal-semiconductor phase transition devices; the detection gain was plotted as a function of the input signal for a posistor and a metal-semiconductor phase transition device. Gains on the order of 100 and more were obtained with the latter. While such devices have the advantage of electrically isolating the input from the output, the speed is governed primarily by the rate of the thermal processes and is approximately inversely proportional to the square of thermocouple branch length. The speed is presently limited to tens of milliseconds, though with the transition to film technology, it may increase by a few orders of magnitude.

  1. Generation of recombinant pestiviruses using a full genome amplification strategy

    DEFF Research Database (Denmark)

    Rasmussen, Thomas Bruun; Reimann, Ilona; Uttenthal, Åse

    pestiviruses. Methods Pestivirus genomes were amplified from either total RNA preparations using long RT-PCR or from infectious cDNA clones using long PCR. Viral RNA was extracted from cell cultures inoculated with pestivirus (e.g. BDV “Gifhorn” or BVDV “CP7”) using a combined Trizol/RNeasy protocol. Total RNA...... was reverse transcribed to cDNA at 50C for 90 minutes using SuperScript III reverse transcriptase (Invitrogen). Full-length PCR amplification was performed using primers specific for the extreme 5’- and 3’-ends of the viral genomes. A T7 promoter was incorporated in the 5’-primers for direct in vitro...... transcription of the amplicons. Long (RT)-PCR was performed using Accuprime High Fidelity or Elongase enzyme mix (Invitrogen), which consists of mixtures of Taq and proofreading Pyrococcus GB-D DNA polymerases. Reactions containing 2 l cDNA were amplified using 94C for 30 seconds followed by 35 cycles of 94°C...

  2. Human minisatellite alleles detectable only after PCR amplification.

    Science.gov (United States)

    Armour, J A; Crosier, M; Jeffreys, A J

    1992-01-01

    We present evidence that a proportion of alleles at two human minisatellite loci is undetected by standard Southern blot hybridization. In each case the missing allele(s) can be identified after PCR amplification and correspond to tandem arrays too short to detect by hybridization. At one locus, there is only one undetected allele (population frequency 0.3), which contains just three repeat units. At the second locus, there are at least five undetected alleles (total population frequency 0.9) containing 60-120 repeats; they are not detected because these tandem repeats give very poor signals when used as a probe in standard Southern blot hybridization, and also cross-hybridize with other sequences in the genome. Under these circumstances only signals from the longest tandemly repeated alleles are detectable above the nonspecific background. The structures of these loci have been compared in human and primate DNA, and at one locus the short human allele containing three repeat units is shown to be an intermediate state in the expansion of a monomeric precursor allele in primates to high copy number in the longer human arrays. We discuss the implications of such loci for studies of human populations, minisatellite isolation by cloning, and the evolution of highly variable tandem arrays.

  3. Magnetic Field Amplification and Flat Spectrum Radio Quasars

    CERN Document Server

    Chen, Xuhui; Zhang, Haocheng; Pohl, Martin; Fossati, Giovanni; Boettcher, Markus; Bailyn, Charles D; Bonning, Erin W; Buxton, Michelle; Coppi, Paolo; Isler, Jedidah; Maraschi, Laura; Urry, Meg

    2014-01-01

    We perform time-dependent, spatially-resolved simulations of blazar emission to evaluate several flaring scenarios related to magnetic-field amplification and enhanced particle acceleration. The code explicitly accounts for light-travel-time effects and is applied to flares observed in the flat spectrum radio quasar (FSRQ) PKS 0208-512, which show optical/{\\gamma}-ray correlation at some times, but orphan optical flares at other times. Changes in both the magnetic field and the particle acceleration efficiency are explored as causes of flares. Generally, external Compton emission appears to describe the available data better than a synchrotron self-Compton scenario, and in particular orphan optical flares are difficult to produce in the SSC framework. X-ray soft-excesses, {\\gamma}-ray spectral hardening, and the detections at very high energies of certain FSRQs during flares find natural explanations in the EC scenario with particle acceleration change. Likewise, optical flares with/without {\\gamma}-ray count...

  4. Amplification of local changes along the timescale processing hierarchy.

    Science.gov (United States)

    Yeshurun, Yaara; Nguyen, Mai; Hasson, Uri

    2017-08-29

    Small changes in word choice can lead to dramatically different interpretations of narratives. How does the brain accumulate and integrate such local changes to construct unique neural representations for different stories? In this study, we created two distinct narratives by changing only a few words in each sentence (e.g., "he" to "she" or "sobbing" to "laughing") while preserving the grammatical structure across stories. We then measured changes in neural responses between the two stories. We found that differences in neural responses between the two stories gradually increased along the hierarchy of processing timescales. For areas with short integration windows, such as early auditory cortex, the differences in neural responses between the two stories were relatively small. In contrast, in areas with the longest integration windows at the top of the hierarchy, such as the precuneus, temporal parietal junction, and medial frontal cortices, there were large differences in neural responses between stories. Furthermore, this gradual increase in neural differences between the stories was highly correlated with an area's ability to integrate information over time. Amplification of neural differences did not occur when changes in words did not alter the interpretation of the story (e.g., sobbing to "crying"). Our results demonstrate how subtle differences in words are gradually accumulated and amplified along the cortical hierarchy as the brain constructs a narrative over time.

  5. Period doubling induced by thermal noise amplification in genetic circuits

    KAUST Repository

    Ruocco, G.

    2014-11-18

    Rhythms of life are dictated by oscillations, which take place in a wide rage of biological scales. In bacteria, for example, oscillations have been proven to control many fundamental processes, ranging from gene expression to cell divisions. In genetic circuits, oscillations originate from elemental block such as autorepressors and toggle switches, which produce robust and noise-free cycles with well defined frequency. In some circumstances, the oscillation period of biological functions may double, thus generating bistable behaviors whose ultimate origin is at the basis of intense investigations. Motivated by brain studies, we here study an “elemental” genetic circuit, where a simple nonlinear process interacts with a noisy environment. In the proposed system, nonlinearity naturally arises from the mechanism of cooperative stability, which regulates the concentration of a protein produced during a transcription process. In this elemental model, bistability results from the coherent amplification of environmental fluctuations due to a stochastic resonance of nonlinear origin. This suggests that the period doubling observed in many biological functions might result from the intrinsic interplay between nonlinearity and thermal noise.

  6. Risks, media and the social amplification of soil contamination

    Energy Technology Data Exchange (ETDEWEB)

    Ouboter, S. [NOK, Networkorganisation for Environmental Quality, Gouda (Netherlands)

    2003-07-01

    Soil experts think of the risks of contaminated sites in terms of adverse effects of toxic substances on human health or environmental quality. In other words, the risk is attributed to the contamination. Social scientists define risk as a situation or event in which something of human value (including humans themselves) has been put at stake and where the outcome is uncertain. Since situations or events are constructions of the human mind, risks are also constructed. A relevant question for a psychologist is to learn how these constructions evolve in the mind of an individual and how this perceived risk influences the individuals' behaviour and well-being. A relevant question for a sociologist is how individuals with their own perceptions, feelings and behaviour interact. Many soil contamination experts experienced that one a site is seen as contaminated by a loathsome source, a chain of adverse reactions can easily put a stigma on that specific location and groups of people associated with that contaminated site. The case of Love Canal is worldwide known as an example of this phenomenon, but many countries have their own national symbol, like Lekkerkerk in the Netherlands. Modern media play an important role in this process. This process is often believed to be irrational and therefore uncontrollable. The question of this workshop is to what level technical soil experts can influence the psychological and social effects of soil contamination, using the social amplification metaphor. (orig.)

  7. A Label-Free and Sensitive Fluorescent Qualitative Assay for Bisphenol A Based on Rolling Circle Amplification/Exonuclease III-Combined Cascade Amplification.

    Science.gov (United States)

    Li, Xia; Song, Juan; Xue, Qing-Wang; You, Fu-Heng; Lu, Xia; Kong, Yan-Cong; Ma, Shu-Yi; Jiang, Wei; Li, Chen-Zhong

    2016-10-21

    Bisphenol A (BPA) detection in drinking water and food packaging materials has attracted much attention since the discovery that BPA can interfere with normal physiological processes and cause adverse health effects. Here, we constructed a label-free aptamer fluorescent assay for selective and sensitive detection of BPA based on the rolling circle amplification (RCA)/Exonuclease III (Exo III)-combined cascade amplification strategy. First, the duplex DNA probe (RP) with anti-BPA aptamer and trigger sequence was designed for BPA recognition and signal amplification. Next, under the action of BPA, the trigger probe was liberated from RP to initiate RCA reaction as primary amplification. Subsequently, the RCA products were used to trigger Exo III assisted secondary amplification with the help of hairpin probes, producing plenty of "G-quadruplex" in lantern-like structures. Finally, the continuously enriched "G-quadruplex lanterns" were lightened by zinc(II)-protoporphyrin IX (ZnPPIX) generating enhanced fluorescence signals. By integrating the primary RCA and secondary Exo III mediated cascade amplification strategy, this method displayed an excellent sensitivity with the detection limits of 5.4 × 10(-17) M. In addition, the anti-BPA aptamer exhibits high recognition ability with BPA, guaranteeing the specificity of detection. The reporter signal probe (G-quadruplex with ZnPPIX) provides a label-free fluorescence signals readout without complicated labeling procedures, making the method simple in design and cost-effective in operation. Moreover, environmental samples analysis was also performed, suggesting that our strategy was reliable and had a great potential application in environmental monitoring.

  8. Gas Chromatography

    Science.gov (United States)

    Qian, Michael C.

    Gas chromatography (GC) has many applications in the analysis of food products. GC has been used for the determination of fatty acids, triglycerides, cholesterol, gases, water, alcohols, pesticides, flavor compounds, and many more. While GC has been used for other food components such as sugars, oligosaccharides, amino acids, peptides, and vitamins, these substances are more suited to analysis by high performance liquid chromatography. GC is ideally suited to the analysis of volatile substances that are thermally stable. Substances such as pesticides and flavor compounds that meet these criteria can be isolated from a food and directly injected into the GC. For compounds that are thermally unstable, too low in volatility, or yield poor chromatographic separation due to polarity, a derivatization step must be done before GC analysis. The two parts of the experiment described here include the analysis of alcohols that requires no derivatization step, and the analysis of fatty acids which requires derivatization. The experiments specify the use of capillary columns, but the first experiment includes conditions for a packed column.

  9. Somatosensory amplification mediates sex differences in psychological distress among cardioverter-defibrillator patients

    DEFF Research Database (Denmark)

    Versteeg, Henneke; Baumert, Jens; Kolb, Christof

    2010-01-01

    The present study examined whether female patients with an implantable cardioverter defibrillator (ICD) report more psychological distress than male patients, and whether somatosensory amplification mediates this relationship. Design: Consecutive ICD patients (N = 241; 33% women) participating in...

  10. Giant amplification of tunnel magnetoresistance in a molecular junction: Molecular spin-valve transistor

    Energy Technology Data Exchange (ETDEWEB)

    Dhungana, Kamal B.; Pati, Ranjit, E-mail: patir@mtu.edu [Department of Physics, Michigan Technological University, Houghton, Michigan 49931 (United States)

    2014-04-21

    Amplification of tunnel magnetoresistance by gate field in a molecular junction is the most important requirement for the development of a molecular spin valve transistor. Herein, we predict a giant amplification of tunnel magnetoresistance in a single molecular spin valve junction, which consists of Ru-bis-terpyridine molecule as a spacer between two ferromagnetic nickel contacts. Based on the first-principles quantum transport approach, we show that a modest change in the gate field that is experimentally accessible can lead to a substantial amplification (320%) of tunnel magnetoresistance. The origin of such large amplification is attributed to the spin dependent modification of orbitals at the molecule-lead interface and the resultant Stark effect induced shift in channel position with respect to the Fermi energy.

  11. Potassium double tungstate waveguides with high ytterbium concentration for optical amplification

    NARCIS (Netherlands)

    Yong, Yean-Sheng

    2017-01-01

    In this thesis, the research work concerning high ytterbium concentration potassium double tungstate waveguides catered for optical amplification purpose is presented. The scope of the research work includes the investigation of spectroscopic and optical gain properties in epitaxy layers with

  12. Near infrared light amplification in Gold diffused Silicon-on-Insulator waveguides

    CERN Document Server

    Stepanov, S

    2016-01-01

    We report near infrared optical amplification in gold diffused silicon-on-insulator waveguides by visible optical pumping. More then 30dB/cm gain was measured for a light carrier at a wavelength of 1.55 microns

  13. Tiny grains give huge gains: nanocrystal-based signal amplification for biomolecule detection.

    Science.gov (United States)

    Tong, Sheng; Ren, Binbin; Zheng, Zhilan; Shen, Han; Bao, Gang

    2013-06-25

    Nanocrystals, despite their tiny sizes, contain thousands to millions of atoms. Here we show that the large number of atoms packed in each metallic nanocrystal can provide a huge gain in signal amplification for biomolecule detection. We have devised a highly sensitive, linear amplification scheme by integrating the dissolution of bound nanocrystals and metal-induced stoichiometric chromogenesis, and demonstrated that signal amplification is fully defined by the size and atom density of nanocrystals, which can be optimized through well-controlled nanocrystal synthesis. Further, the rich library of chromogenic reactions allows implementation of this scheme in various assay formats, as demonstrated by the iron oxide nanoparticle linked immunosorbent assay (ILISA) and blotting assay developed in this study. Our results indicate that, owing to the inherent simplicity, high sensitivity and repeatability, the nanocrystal based amplification scheme can significantly improve biomolecule quantification in both laboratory research and clinical diagnostics. This novel method adds a new dimension to current nanoparticle-based bioassays.

  14. Double trouble: medical implications of genetic duplication and amplification in bacteria.

    Science.gov (United States)

    Craven, Sarah H; Neidle, Ellen L

    2007-06-01

    Gene amplification allows organisms to adapt to changing environmental conditions. This type of increased gene dosage confers selectable benefits, typically by augmenting protein production. Gene amplification is a reversible process that does not require permanent genetic change. Although transient, altered gene dosage has significant medical impact. Recent examples of amplification in bacteria, described here, affect human disease by modifying antibiotic resistance, the virulence of pathogens, vaccine efficacy and antibiotic biosynthesis. Amplification is usually a two-step process whereby genetic duplication (step one) promotes further increases in copy number (step two). Both steps have important evolutionary significance for the emergence of innovative gene functions. Recent genome sequence analyses illustrate how genome plasticity can affect the evolution and immunogenic properties of bacterial pathogens.

  15. Worst-case amplification of disturbances in inertialess Couette flow of viscoelastic fluids

    CERN Document Server

    Lieu, Binh K; Kumar, Satish

    2013-01-01

    Amplification of deterministic disturbances in inertialess shear-driven channel flows of viscoelastic fluids is examined by analyzing the frequency responses from spatio-temporal body forces to the velocity and polymer stress fluctuations. In strongly elastic flows, we show that disturbances with large streamwise length scales may be significantly amplified even in the absence of inertia. For fluctuations without streamwise variations, we derive explicit analytical expressions for the dependence of the worst-case amplification (from different forcing to different velocity and polymer stress components) on the Weissenberg number ($We$), the maximum extensibility of the polymer chains ($L$), the viscosity ratio, and the spanwise wavenumber. For the Oldroyd-B model, the amplification of the most energetic components of velocity and polymer stress fields scales as $We^2$ and $We^4$. On the other hand, finite extensibility of polymer molecules limits the largest achievable amplification even in flows with infinite...

  16. Patterning effects in multi-purpose amplification by a quantum dot amplifier

    DEFF Research Database (Denmark)

    Poel, Mike van der; Berg, Tommy Winther; Mørk, Jesper;

    2006-01-01

    The potential for ultrafast signal processing in a quantum dot amplifier is investigated by observing the gain dynamics during amplification of femtosecond pulses in rapid succession. Significant patterning is seen at picosecond pulse separation....

  17. SPERM RNA AMPLIFICATION FOR GENE EXPRESSION PROFILING BY DNA MICROARRAY TECHNOLOGY

    Science.gov (United States)

    Sperm RNA Amplification for Gene Expression Profiling by DNA Microarray TechnologyHongzu Ren, Kary E. Thompson, Judith E. Schmid and David J. Dix, Reproductive Toxicology Division, NHEERL, Office of Research and Development, US Environmental Protection Agency, Research Triang...

  18. Drastic disorded-induced reduction of signal amplification in scale-free networks

    CERN Document Server

    Chacón, Ricardo

    2014-01-01

    Understanding information transmission across a network is a fundamental task for controlling and manipulating both biological and man-made information processing systems. Here, we show how topological resonant-like amplification effects in scale-free networks of signaling devices are drastically reduced when phase disorder in the external signals is considered. This is demonstrated theoretically by means of a star-like network of overdamped bistable systems, and confirmed numerically by simulations of scale-free networks of such systems. The taming effect of the phase disorder is found to be sensitive to the amplification's strength, while the topology-induced amplification mechanism is robust against this kind of quenched disorder in the sense that it does not significantly change the values of the coupling strength where amplification is maximum in its absence.

  19. Supernova-driven Turbulence and Magnetic Field Amplification in Disk Galaxies

    CERN Document Server

    Gressel, Oliver

    2010-01-01

    Supernovae are known to be the dominant energy source for driving turbulence in the interstellar medium. Yet, their effect on magnetic field amplification in spiral galaxies is still poorly understood. Analytical models based on the uncorrelated-ensemble approach predicted that any created field will be expelled from the disk before a significant amplification can occur. By means of direct simulations of supernova-driven turbulence, we demonstrate that this is not the case. Accounting for vertical stratification and galactic differential rotation, we find an exponential amplification of the mean field on timescales of 100Myr. The self-consistent numerical verification of such a "fast dynamo" is highly beneficial in explaining the observed strong magnetic fields in young galaxies. We, furthermore, highlight the importance of rotation in the generation of helicity by showing that a similar mechanism based on Cartesian shear does not lead to a sustained amplification of the mean magnetic field. This finding impr...

  20. Enhanced Amplification and Fan-Out Operation in an All-Magnetic Transistor.

    Science.gov (United States)

    Barman, Saswati; Saha, Susmita; Mondal, Sucheta; Kumar, Dheeraj; Barman, Anjan

    2016-09-14

    Development of all-magnetic transistor with favorable properties is an important step towards a new paradigm of all-magnetic computation. Recently, we showed such possibility in a Magnetic Vortex Transistor (MVT). Here, we demonstrate enhanced amplification in MVT achieved by introducing geometrical asymmetry in a three vortex sequence. The resulting asymmetry in core to core distance in the three vortex sequence led to enhanced amplification of the MVT output. A cascade of antivortices travelling in different trajectories including a nearly elliptical trajectory through the dynamic stray field is found to be responsible for this amplification. This asymmetric vortex transistor is further used for a successful fan-out operation, which gives large and nearly equal gains in two output branches. This large amplification in magnetic vortex gyration in magnetic vortex transistor is proposed to be maintained for a network of vortex transistor. The above observations promote the magnetic vortex transistors to be used in complex circuits and logic operations.

  1. Parasitic bipolar amplification in a single event transient and its temperature dependence

    Institute of Scientific and Technical Information of China (English)

    Liu Zheng; Chen Shu-Ming; Chen Jian-Jun; Qin Jun-Rui; Liu Rong-Rong

    2012-01-01

    Using three-dimensional technology computer-aided design (TCAD) simulation,parasitic bipolar amplification in a single event transient (SET) current of a single transistor and its temperature dependence are studied.We quantify the contributions of different current components in a SET current pulse,and it is found that the proportion of parasitic bipolar amplification in total collected charge is about 30% in both 130-nm and 90-nm technologies.The temperature dependence of parasitic bipolar amplification and the mechanism of the SET pulse are also investigated and quantified.The results show that the proportion of charge induced by parasitic bipolar increases with rising temperature,which illustrates that the parasitic bipolar amplification plays an important role in the charge collection of a single transistor.

  2. On the mechanism of gene amplification induced under stress in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    2006-04-01

    Full Text Available Gene amplification is a collection of processes whereby a DNA segment is reiterated to multiple copies per genome. It is important in carcinogenesis and resistance to chemotherapeutic agents, and can underlie adaptive evolution via increased expression of an amplified gene, evolution of new gene functions, and genome evolution. Though first described in the model organism Escherichia coli in the early 1960s, only scant information on the mechanism(s of amplification in this system has been obtained, and many models for mechanism(s were possible. More recently, some gene amplifications in E. coli were shown to be stress-inducible and to confer a selective advantage to cells under stress (adaptive amplifications, potentially accelerating evolution specifically when cells are poorly adapted to their environment. We focus on stress-induced amplification in E. coli and report several findings that indicate a novel molecular mechanism, and we suggest that most amplifications might be stress-induced, not spontaneous. First, as often hypothesized, but not shown previously, certain proteins used for DNA double-strand-break repair and homologous recombination are required for amplification. Second, in contrast with previous models in which homologous recombination between repeated sequences caused duplications that lead to amplification, the amplified DNAs are present in situ as tandem, direct repeats of 7-32 kilobases bordered by only 4 to 15 base pairs of G-rich homology, indicating an initial non-homologous recombination event. Sequences at the rearrangement junctions suggest nonhomologous recombination mechanisms that occur via template switching during DNA replication, but unlike previously described template switching events, these must occur over long distances. Third, we provide evidence that 3'-single-strand DNA ends are intermediates in the process, supporting a template-switching mechanism. Fourth, we provide evidence that lagging

  3. Accelerated Gas Carburizing (URX Gas Carburizing)

    Institute of Scientific and Technical Information of China (English)

    Yoshikazu Shimosato; Mamoru Kamitani; Hiroyuki Nakatsu

    2004-01-01

    URX gas carburizing is an accelerated gas carburizing method with 50% CO + 50% H2 gas which comes from CH4 gas + CO2 gas. By using this gas composition, the carburizing reaction rate increases to the maximum and the controllability of carbon potential improves. A carbon mass flow rate is the product of the carburizing reaction rate multiplied by the difference of carbon percent between carbon potential of the gas and the carbon content of the surface of treated steel parts. We have obtained excellent results from the experimental tests at our laboratory as mentioned bellow. 1)Carburizing time can be shortened by 40% for 0.5 - 0.9 mm effective case depth. 2) Uniform carburizing case depth 3) Less internal oxidation with the same case depth. We have already developed the new roller hearth type continuous carburizing furnace and the new URX gas generator.

  4. Optical-parametric-amplification applications to complex images

    Science.gov (United States)

    Vaughan, Peter M.

    2011-12-01

    Ultrafast optical pulses have many useful features. One in particular is their ability to exploit nonlinear processes due to their extremely short durations. We have used ultrafast optical pulses, primarily focused on the nonlinear processes of Polarization Gating and of Optical Parametric Amplification, one for measurement and the other for imaging purposes. For measurement, we have demonstrated a robust method of measurement to simultaneously measure both optical pulses used in a pump-probe type configuration. In these measurements, no initial information beyond the nonlinear interaction between the pulses is required. We refer to this method of pulse measurement as Double-Blind Polarization Gating FROG[1]. We have demonstrated this single-shot method for measuring two unknown pulses using one device. We have demonstrated this technique on three separate pulse pairs. We measured two Gaussian pulses with different amounts of chirp. We measured two double pulses with different pulse separations, and we have measured two extremely different pulses, where one was simple Gaussian and the other was a pulse train produced by an etalon. This method has no non-trivial ambiguities, has a reliable algorithm, and is automatically phase matched for all spectral bandwidths. In simulations[2], this method has proven to be extremely robust, measuring very complicated pulses with TBPs of ˜100 even in the presence of noise. In addition to pulse measurement, we have demonstrated the processes of Optical Parametric Amplification (OPA) applicability to imaging of complex objects[3]. We have done this where the Fourier transform plane is used during the interaction. We have amplified and wavelength converted a complex image. We report imaging of spatial features from 1.1 to 10.1 line pairs/millimeter (lp/mm) in the vertical dimension and from 2.0 to 16.0 lp/mm in the horizontal dimension. We observe a gain of ˜100, and, although our images were averaged over many shots, we used a

  5. PCR amplification of microsatellites from single cells of Karenia brevis preserved in Lugol's iodine solution.

    Science.gov (United States)

    Henrichs, D W; Renshaw, M A; Santamaria, C A; Richardson, B; Gold, J R; Campbell, L

    2008-01-01

    A simple and effective protocol is described for multiplex polymerase chain reaction (PCR) amplification of single cells of Karenia brevis. The protocol requires minimum processing, avoids additions that might dilute target DNA template, and can be used on cells preserved in Lugol's iodine preservative. Destaining of Lugol's-preserved cells with sodium thiosulfate allowed successful amplification of single-copy, nuclear-encoded microsatellites in single cells of K. brevis that have been preserved for up to 6 years.

  6. Ligation-Independent Mechanism of Multiplex Ligation-Dependent Probe Amplification

    OpenAIRE

    Uno, Naoki; Yanagihara, Katsunori

    2014-01-01

    Multiplex ligation-dependent probe amplification (MLPA) is a widely used technique for detecting genomic structural variants. The technique is based on hybridization and ligation, followed by amplification of the ligation products. Therefore, ligation is considered a fundamental process that determines the feasibility and fidelity of MLPA. However, despite the widespread use of this technique, its reaction mechanism has not been fully analyzed. Herein, we describe a ligation-independent pathw...

  7. Efficient chirped-pulse amplification of sub-20 fs laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Matsuoka, Shinichi; Yamakawa, Koichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    We have developed a model for ultrabroadband and ultrashort pulse amplification including the effects of a pulse shaper for regenerative pulse shaping, gain narrowing and gain saturation in the amplifiers. Thin solid etalons are used to control both gain narrowing and gain saturation during amplification. This model has been used to design an optimized Ti:sapphire amplifier system for producing efficiently pulses of < 20-fs duration with approaching peak and average powers of 100 TW and 20 W. (author)

  8. Method for chemical amplification based on fluid partitioning in an immiscible liquid

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Brian L.; Colston, Bill W.; Elkin, Christopher J.

    2017-02-28

    A system for nucleic acid amplification of a sample comprises partitioning the sample into partitioned sections and performing PCR on the partitioned sections of the sample. Another embodiment of the invention provides a system for nucleic acid amplification and detection of a sample comprising partitioning the sample into partitioned sections, performing PCR on the partitioned sections of the sample, and detecting and analyzing the partitioned sections of the sample.

  9. Picoradian deflection measurement with an interferometric quasi-autocollimator using weak value amplification.

    Science.gov (United States)

    Turner, Matthew D; Hagedorn, Charles A; Schlamminger, Stephan; Gundlach, Jens H

    2011-04-15

    We present an "interferometric quasi-autocollimator" that employs weak value amplification to measure angular deflections of a target mirror. The device has been designed to be insensitive to all translations of the target. We present a conceptual explanation of the amplification effect used by the device. An implementation of the device demonstrates sensitivities better than 10 picoradians per root hertz between 10 and 200 Hz.

  10. Isolation and amplification of mRNA within a simple microfluidic lab on a chip.

    Science.gov (United States)

    Reinholt, Sarah J; Behrent, Arne; Greene, Cassandra; Kalfe, Ayten; Baeumner, Antje J

    2014-01-07

    The major modules for realizing molecular biological assays in a micro-total analysis system (μTAS) were developed for the detection of pathogenic organisms. The specific focus was the isolation and amplification of eukaryotic mRNA within a simple, single-channel device for very low RNA concentrations that could then be integrated with detection modules. The hsp70 mRNA from Cryptosporidium parvum was used as a model analyte. Important points of study were surface chemistries within poly(methyl methacrylate) (PMMA) microfluidic channels that enabled specific and sensitive mRNA isolation and amplification reactions for very low mRNA concentrations. Optimal conditions were achieved when the channel surface was carboxylated via UV/ozone treatment followed by the immobilization of polyamidoamine (PAMAM) dendrimers on the surface, thus increasing the immobilization efficiency of the thymidine oligonucleotide, oligo(dT)25, and providing a reliable surface for the amplification reaction, importantly, without the need for blocking agents. Additional chemical modifications of the remaining active surface groups were studied to avoid nonspecific capturing of nucleic acids and hindering of the mRNA amplification at low RNA concentrations. Amplification of the mRNA was accomplished using nucleic acid sequence-based amplification (NASBA), an isothermal, primer-dependent technique. Positive controls consisting of previously generated NASBA amplicons could be diluted 10(15) fold and still result in successful on-chip reamplification. Finally, the successful isolation and amplification of mRNA from as few as 30 C. parvum oocysts was demonstrated directly on-chip and compared to benchtop devices. This is the first proof of successful mRNA isolation and NASBA-based amplification of mRNA within a simple microfluidic device in relevant analytical volumes.

  11. Apparatus for chemical amplification based on fluid partitioning in an immiscible liquid

    Science.gov (United States)

    Anderson, Brian L [Lodi, CA; Colston, Bill W [San Ramon, CA; Elkin, Christopher J [San Ramon, CA

    2012-05-08

    A system for nucleic acid amplification of a sample comprises partitioning the sample into partitioned sections and performing PCR on the partitioned sections of the sample. Another embodiment of the invention provides a system for nucleic acid amplification and detection of a sample comprising partitioning the sample into partitioned sections, performing PCR on the partitioned sections of the sample, and detecting and analyzing the partitioned sections of the sample.

  12. 90 mJ parametric chirped pulse amplification of 10 fs pulses.

    Science.gov (United States)

    Tavella, Franz; Marcinkevicius, Andrius; Krausz, Ferenc

    2006-12-25

    We demonstrate the amplification of broadband pulses from a Ti:Sapphire oscillator by non-collinear optical parametric chirped-pulse amplification technique in a type-I BBO crystal to energies of 90 mJ. Partial compression of the amplified pulses is demonstrated down to a 10 fs duration. These parameters come in combination with good spatial quality and focusability of the amplified beam.

  13. Patterning effects in multi-purpose amplification by a quantum dot amplifier

    DEFF Research Database (Denmark)

    Poel, Mike van der; Berg, Tommy Winther; Mørk, Jesper

    2006-01-01

    The potential for ultrafast signal processing in a quantum dot amplifier is investigated by observing the gain dynamics during amplification of femtosecond pulses in rapid succession. Significant patterning is seen at picosecond pulse separation.......The potential for ultrafast signal processing in a quantum dot amplifier is investigated by observing the gain dynamics during amplification of femtosecond pulses in rapid succession. Significant patterning is seen at picosecond pulse separation....

  14. Noiseless phase quadrature amplification via an electro-optic feed-forward technique

    CERN Document Server

    Buchler, B C; Ralph, T C; Buchler, Ben C.; Huntington, Elanor H.; Ralph, Timothy C.

    1999-01-01

    Theoretical results are presented which show that noiseless phase quadrature amplification is possible, and limited experimentally only by the efficiency of the phase detection system. Experimental results obtained using a Nd:YAG laser show a signal gain of 10dB and a signal transfer ratio of T_s=0.9. This result easily exceeds the standard quantum limit for signal transfer. The results also explicitly demonstrate the phase sensitive nature of the amplification process.

  15. Fiber Optical Parametric Chirped Pulse Amplification of Sub-Picosecond Pulses

    DEFF Research Database (Denmark)

    Cristofori, Valentina; Lali-Dastjerdi, Zohreh; Da Ros, Francesco

    2013-01-01

    We demonstrate experimentally, for the first time to our knowledge, fiber optical parametric chirped pulse amplification of 400-fs pulses. The 400-fs signal is stretched, amplified by 26 dB and compressed back to 500 fs.......We demonstrate experimentally, for the first time to our knowledge, fiber optical parametric chirped pulse amplification of 400-fs pulses. The 400-fs signal is stretched, amplified by 26 dB and compressed back to 500 fs....

  16. Three-dimensional carbon interdigitated electrode arrays for redox-amplification.

    Science.gov (United States)

    Kamath, Rahul R; Madou, Marc J

    2014-03-18

    Three-dimensional (3D) carbon interdigitated electrode arrays (IDEAs) were fabricated using inexpensive, conventional, UV photolithography of SU-8 with modified exposure and post exposure bake settings followed by pyrolysis in an inert environment. The sensor performance was investigated as a function of both the IDEA digit width/gap ratio and digit height under flow and no flow conditions. We demonstrated a gradual increase in redox amplification with an increase in the IDEA digit width/gap ratio. The highest amplification of 37 was obtained for a width/gap ratio of 1.58 and for an electrode height of 1.1 μm. Redox amplification also increases significantly with an increase in the IDEA height, from a factor of 9 at a 0.22 μm digit height to a factor of 37 at a 1.1 μm height. The effect of potential sweep rates on redox amplification was also investigated. As the sweep rate was decreased from 50 mV/s to 5 mV/s, the collection efficiency increased from 0.92 to 0.97, whereas the amplification increased from 7 to 25. Under flow conditions, the amplification decreases substantially as the cycling of the redox species is impeded by convection, resulting in a drop in collection efficiency. The highest amplification of 37 dropped to 4 for the same electrode at a flow rate of 500 nL/s. Under flow, redox amplification increased with an increase in the IDEA height.

  17. Detection of biological molecules using boronate-based chemical amplification and optical sensors

    Energy Technology Data Exchange (ETDEWEB)

    Antwerp, W.P. van; Mastrototaro, J.J.; Lane, S.M.; Satcher, J.H. Jr.; Darrow, C.B.; Peyser, T.A.; Harder, J.

    1999-12-14

    Methods are provided for the determination of the concentration of biological levels of polyhydroxylated compounds, particularly glucose. The methods utilize an amplification system that is an analyte transducer immobilized in a polymeric matrix, where the system is implantable and biocompatible. Upon interrogation by an optical system, the amplification system produces a signal capable of detection external to the skin of the patient. Quantitation of the analyte of interest is achieved by measurement of the emitted signal.

  18. Dihydrofolate reductase amplification and sensitization to methotrexate of methotrexate-resistant colon cancer cells

    DEFF Research Database (Denmark)

    Morales Torres, Christina; García, Maria J; Ribas, Maria;

    2009-01-01

    Gene amplification is one of the most frequent manifestations of genomic instability in human tumors and plays an important role in tumor progression and acquisition of drug resistance. To better understand the factors involved in acquired resistance to cytotoxic drugs via gene amplification, we ...... to a second round of treatment if left untreated during a sufficient period of time. [Mol Cancer Ther 2009;8(2):424-32]....

  19. Restricted 12p Amplification and RAS Mutation in Human Germ Cell Tumors of the Adult Testis

    Science.gov (United States)

    Roelofs, Helene; Mostert, Marijke C.; Pompe, Kirsten; Zafarana, Gaetano; van Oorschot, Monique; van Gurp, Ruud J. H. L. M.; Gillis, Ad J. M.; Stoop, Hans; Beverloo, Berna; Oosterhuis, J. Wolter; Bokemeyer, Carsten; Looijenga, Leendert H. J.

    2000-01-01

    Human testicular germ-cell tumors of young adults (TGCTs), both seminomas and nonseminomas, are characterized by 12p overrepresentation, mostly as isochromosomes, of which the biological and clinical significance is still unclear. A limited number of TGCTs has been identified with an additional high-level amplification of a restricted region of 12p including the K-RAS proto-oncogene. Here we show that the incidence of these restricted 12p amplifications is ∼8% in primary TGCTs. Within a single cell formation of i(12p) and restricted 12p amplification is mutually exclusive. The borders of the amplicons cluster in short regions, and the amplicon was never found in the adjacent carcinoma in situ cells. Seminomas with the restricted 12p amplification virtually lacked apoptosis and the tumor cells showed prolonged in vitro survival like seminoma cells with a mutated RAS gene. However, no differences in proliferation index between these different groups of seminomas were found. Although patients with a seminoma containing a homogeneous restricted 12p amplification presented at a significantly younger age than those lacking it, the presence of a restricted 12p amplification/RAS mutation did not predict the stage of the disease at clinical presentation and the treatment response of primary seminomas. In 55 primary and metastatic tumors from 44 different patients who failed cisplatinum-based chemotherapy, the restricted 12p amplification and RAS mutations had the same incidence as in the consecutive series of responding patients. These data support the model that gain of 12p in TGCTs is related to invasive growth. It allows tumor cells, in particular those showing characteristics of early germ cells (ie, the seminoma cells), to survive outside their specific microenvironment. Overexpression of certain genes on 12p probably inhibits apoptosis in these tumor cells. However, the copy numbers of the restricted amplification of 12p and K-RAS mutations do not predict response

  20. CCNE1 amplification is associated with aggressive potential in endometrioid endometrial carcinomas

    OpenAIRE

    Nakayama, Kentaro; RAHMAN, MOHAMMED TANJIMUR; Rahman, Munmun; NAKAMURA, Kohei; Ishikawa, Masako; Katagiri, Hiroshi; Sato, Emi; Ishibashi, Tomoka; IIDA, KOUJI; Ishikawa, Noriyuki; Kyo, Satoru

    2015-01-01

    The clinicopathological significance of amplification was investigated of the gene encoding cyclin E (CCNE1) and we assessed whether CCNE1 was a potential target in endometrioid endometrial carcinomas. CCNE1 amplification and CCNE1 or F-box and WD repeat domain-containing 7 (FBXW7) expression in endometrial endometrioid carcinoma was assessed by immunohistochemistry and fluorescence in situ hybridization. CCNE1 knockdown by small interfering RNA (siRNA) was used to assess the CCNE1 function. ...