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Sample records for dephasing time t2

  1. Dimensional crossover of the dephasing time in disordered mesoscopic rings

    Science.gov (United States)

    Treiber, M.; Yevtushenko, O. M.; Marquardt, F.; von Delft, J.; Lerner, I. V.

    2009-11-01

    We study dephasing by electron interactions in a small disordered quasi-one-dimensional (1D) ring weakly coupled to leads. We use an influence functional for quantum Nyquist noise to describe the crossover for the dephasing time τφ(T) from diffusive or ergodic 1D (τφ-1∝T2/3,T1) to zero-dimensional (0D) behavior (τφ-1∝T2) as T drops below the Thouless energy. The crossover to 0D, predicted earlier for two-dimensional and three-dimensional systems, has so far eluded experimental observation. The ring geometry holds promise of meeting this long-standing challenge, since the crossover manifests itself not only in the smooth part of the magnetoconductivity but also in the amplitude of Altshuler-Aronov-Spivak oscillations. This allows signatures of dephasing in the ring to be cleanly extracted by filtering out those of the leads.

  2. Dephasing time of a positron accelerated by a laser pulse

    Institute of Scientific and Technical Information of China (English)

    杜春光; 李师群

    2002-01-01

    The dephasing time of a positron in the total field associated with a laser pulse in a plasma is studied numerically.It is shown that the dynamics of the positron is quite different from that of an electron due to the electrostatic potential in the body of the pulse. The dephasing time of the positron increases with the pulse length and decreases with the pulse intensity nonlinearly. In the long pulse case (L> λp) the dephasing time is proportional to the pulse length. These results provide a scientific basis for experiments to observe the positron acceleration scheme, and may be important to the physics of laser-particle interactions in multi-component plasmas.

  3. Wave attenuation model for dephasing and measurement of conditional times

    Indian Academy of Sciences (India)

    A M Jayannavar; Colin Benjamin

    2002-08-01

    Inelastic scattering induces dephasing in mesoscopic systems. An analysis of previous models to simulate inelastic scattering in such systems is presented and a relatively new model based on wave attenuation is introduced. The problem of Aharonov–Bohm (AB) oscillations in conductance of a mesoscopic ring is studied. We show that the conductance is symmetric under flux reversal and the visibility of AB oscillations decays to zero as a function of the incoherence parameter, signaling dephasing. Further the wave attenuation model is applied to a fundamental problem in quantum mechanics, that of the conditional (reflection/transmission) times spent in a given region of space by a quantum particle before scattering off from that region.

  4. Dephasing time and damping mechanisms of surface plasmon polaritons in gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Borg, Nils; Sanchez Blazquez, David; Hendrich, Christian; Hubenthal, Frank; Traeger, Frank [Institut fuer Physik und Center for Interdisciplinary Nanostructure Science and Technology - CINSaT, Universitaet Kassel, Heinrich-Plett-Strasse 40, D-34132 Kassel (Germany)

    2007-07-01

    The ultrafast electron dynamics in gold nanoparticles (NPs) was studied by measuring the dephasing time T{sub 2} of the surface plasmon polariton by means of persistent spectral hole burning. The dephasing time of gold grown on sapphire and TiO{sub 2} substrates was measured as a function of photon energy and the particle size. Dephasing times ranging from 5 to 17 fs were extracted. Furthermore, an explicit influence of the reduced dimension of the NPs has been determined, which plays a role for NPs with radii below 12 nm already. Most importantly, a dependence of T{sub 2} on the decreasing particle dimensions which fulfilled a 1/R-dependence was found and we could obtain a damping parameter for gold on sapphire of A=(0.32{+-}0.06) nm/fs. Comparison with other measurements as well as with theoretical predictions could identify surface scattering and Landau-damping as the most important mechanisms. Recent further experiments on gold NPs supported on TiO{sub 2} showed a further reduction of the dephasing time. For example, for NPs with a radius of approximately 13 nm we observed a decrease from T{sub 2}{approx}15 fs for NPs grown on sapphire to T{sub 2}{approx}12 fs for NPs grown on TiO{sub 2} at a photon energy of 1.65 eV. This indicates an additional damping mechanism, i.e. chemical interface damping.

  5. Dynamical decoupling sequences for multi-qubit dephasing suppression and long-time quantum memory

    Science.gov (United States)

    Paz-Silva, Gerardo A.; Lee, Seung-Woo; Green, Todd J.; Viola, Lorenza

    2016-07-01

    We consider a class of multi-qubit dephasing models that combine classical noise sources and linear coupling to a bosonic environment, and are controlled by arbitrary sequences of dynamical decoupling pulses. Building on a general transfer filter-function framework for open-loop control, we provide an exact representation of the controlled dynamics for arbitrary stationary non-Gaussian classical and quantum noise statistics, with analytical expressions emerging when all dephasing sources are Gaussian. This exact characterization is used to establish two main results. First, we construct multi-qubit sequences that ensure maximum high-order error suppression in both the time and frequency domain and that can be exponentially more efficient than existing ones in terms of total pulse number. Next, we show how long-time multi-qubit storage may be achieved by meeting appropriate conditions for the emergence of a fidelity plateau under sequence repetition, thereby generalizing recent results for single-qubit memory under Gaussian dephasing. In both scenarios, the key step is to endow multi-qubit sequences with a suitable displacement anti-symmetry property, which is of independent interest for applications ranging from environment-assisted entanglement generation to multi-qubit noise spectroscopy protocols.

  6. Dephasing times in quantum dots due to elastic LO phonon-carrier collisions

    DEFF Research Database (Denmark)

    Uskov, A. V.; Jauho, Antti-Pekka; Tromborg, Bjarne

    2000-01-01

    Interpretation of experiments on quantum dot (QD) lasers presents a challenge: the phonon bottleneck, which should strongly suppress relaxation and dephasing of the discrete energy states, often seems to be inoperative. We suggest and develop a theory for an intrinsic mechanism for dephasing in Q...

  7. (T2L2) Time Transfer by Laser Link

    Science.gov (United States)

    Veillet, Christian; Fridelance, Patricia

    1995-05-01

    T2L2 (Time Transfer by Laser Link) is a new generation time transfer experiment based on the principles of LASSO (Laser Synchronization from Synchronous Orbit) and used with an operational procedure developed at OCA (Observatoire de la Cote d'Azur) during the active intercontinental phase of LASSO. The hardware improvements could lead to a precision better than 10 ps for time transfer (flying clock monitoring or ground based clock comparison). Such a package could fly on any spacecraft with a stable clock. It has been developed in France in the frame of the PHARAO project (cooled atom clock in orbit) involving CNES and different laboratories. But T2L2 could fly on any spacecraft carrying a stable oscillator. A GPS satellite would be a good candidate, as T2L2 could allow to link the flying clock directly to ground clocks using light, aiming to important accuracy checks, both for time and for geodesy. Radioastron (a flying VLBI antenna with a H-maser) is also envisioned, waiting for a PHARAO flight. The ultimate goal of T2L2 is to be part of more ambitious missions, as SORT (Solar Orbit Relativity Test), aiming to examine aspects of the gravitation in the vicinity of the Sun.

  8. Time-Resolved Speckle Analysis: A New Approach to Coherence and Dephasing of Optical Excitations in Solids

    DEFF Research Database (Denmark)

    Langbein, Wolfgang Werner; Hvam, Jørn Märcher; Zimmermann, R.

    1999-01-01

    A new method to measure the time-dependent coherence of both homogeneously and inhomogeneously broadened optical excitations in solids is presented. The coherence degree of resonantly excited light emission is deduced from the intensity fluctuations over the emission directions (speckles......). This method determines the decays of intensity and coherence separately, thus distinguishing lifetime from pure dephasing. The secondary emission of excitons in semiconductor quantum wells is investigated. Here the combination of static disorder and inelastic scattering leads to a partially coherent emission...

  9. T2L2 - Time Transfer by Laser Link

    Science.gov (United States)

    Weick, J.; Samain, E.; Bério, Ph.

    2005-12-01

    T2L2 is an experiment based on laser ranging technique coupled with time-frequency metrology. The goal consists in synchronizing ground and space clocks using short light pulses travelling between the ground and a satellite. The instrument will be integrated to the Jason-2 altimetric satellite launched in 2008. The experiment should enhance the performances of time transfert by one or two magnitudes compared to existing microwave techniques like GPS and Two-Way.

  10. Impact of different coils on biochemical T2 and T2* relaxation time mapping of articular patella cartilage.

    Science.gov (United States)

    Pachowsky, Milena L; Trattnig, Siegfried; Apprich, Sebastian; Mauerer, Andreas; Zbyn, Stephan; Welsch, Goetz H

    2013-11-01

    The purpose of our study was to assess T2 and T2* relaxation time values of patella cartilage in healthy volunteers using three different coils at 3.0 Tesla MRI and their influence on the quantitative values. Fifteen volunteers were examined on the same 3-Tesla MR unit using three different coils: (i) a dedicated eight-channel knee phased-array coil; (ii) an eight-channel multi-purpose coil, and (iii) a one-channel 1H surface coil. T2 and T2* relaxation time measurements were prepared by a multi-echo spinecho respectively a gradient-echo sequence. A semi-automatic region-of-interest analysis was performed for patella cartilage. To allow stratification, a subregional analysis was carried out (deep-superficial cartilage layer). Statistical analysis-of-variance was performed. The mean quantitative T2 values showed statistically significant differences in all comparison combinations. The differences between the mean quantitative T2* values were slightly less pronounced than the T2 evaluation and only the comparison between (i) and (ii) showed a significant difference. The results of T2 and T2* values showed, independent of the used coil, higher values in the superficial zone compared to the deep zone (p < 0.05). Looking at the signal alterations, all coils showed clearly higher values (and thus more signal alterations as a sign of noise) in the deep layer. The validation of the reliability showed a high intra-class correlation coefficient and hence a very high plausibility (ICC was between 0.870 and 0.905 for T2 mapping and between 0.879 and 0.888 for T2* mapping). The present results demonstrate that biochemical T2 and T2* mapping is significantly dependent on the utilized coil.

  11. Real-time path-integral approach for dissipative quantum dot-cavity quantum electrodynamics: impure dephasing-induced effects

    Science.gov (United States)

    Nahri, Davoud G.; Mathkoor, Faisal H. A.; Ooi, C. H. Raymond

    2017-02-01

    A dissipative quantum dot (QD)-cavity system, where the QD is initially prepared in the excited state with no photon in the cavity, coupled to a longitudinal acoustic (LA) phonon reservoir is studied using a numerically exact real-time path-integral approach. Three distinct dynamical regimes of weak (WC), strong (SC), and coherent coupling (CC) are discussed and more accurate conditions identifying them are presented. Our results show that to have the CC regime, which is characterized by clear vacuum Rabi oscillation (VRO), vacuum Rabi splitting (VRS) should be larger than the sum of the widths of the corresponding peaks. In order to distinguish between contributions of population decay and impure dephasing, induced by LA phonon bath and the dissipations, we propose a two-part phenomenological expression, corresponding to the population decay and impure dephasing, which fits the QD-cavity decay curves perfectly and is used to calculate the corresponding spectra. We demonstrate that the effective population decay rate (the emission rate) increases from the carrier recombination rate to a maximum value, which is the mean of the QD and cavity dissipation rates, with QD-cavity coupling strength. To study the role of the effective impure dephasing rate on the width of the central peak of the spectra we introduce a quantity that can also be applied in determining the distinct coupling regimes. This quantity enables us to identify the onset of the SC regime as the point where the impure dephasing term begins to contribute to the central band of the spectrum significantly, as a result of the existence of VRO with a very small frequency (unclear VRO) at the corresponding decay curve. Its contribution to the width of the central peak increases with the coupling strength up to the onset of the CC regime, then reduces as a result of the appearance of sidebands in the spectra, which originates from clear VRO. The effective population decay and impure dephasing rate contribute

  12. Time projection chambers for the T2K near detectors

    Energy Technology Data Exchange (ETDEWEB)

    Abgrall, N. [Physics Section, University of Geneva (Switzerland); Andrieu, B. [LPNHE, IN2P3-CNRS, 75252 Paris CEDEX 05 (France); Baron, P. [Irfu/DSM, CEA-Saclay, 91191 Gif/Yvette CEDEX (France); Bene, P. [Physics Section, University of Geneva (Switzerland); Berardi, V. [INFN, Sezione di Bari, Bari (Italy); Beucher, J. [Irfu/DSM, CEA-Saclay, 91191 Gif/Yvette CEDEX (France); Birney, P. [TRIUMF, Vancouver (Canada); Department of Physics and Astronomy, University of Victoria, Victoria (Canada); Blaszczyk, F. [Irfu/DSM, CEA-Saclay, 91191 Gif/Yvette CEDEX (France); Blondel, A. [Physics Section, University of Geneva (Switzerland); Bojechko, C. [Department of Physics and Astronomy, University of Victoria, Victoria (Canada); Boyer, M. [Irfu/DSM, CEA-Saclay, 91191 Gif/Yvette CEDEX (France); Cadoux, F. [Physics Section, University of Geneva (Switzerland); Calvet, D. [Irfu/DSM, CEA-Saclay, 91191 Gif/Yvette CEDEX (France); Catanesi, M.G. [INFN, Sezione di Bari, Bari (Italy); Cervera, A. [IFIC, University of Valencia and CSIC, Valencia (Spain); Colas, P.; De La Broise, X.; Delagnes, E.; Delbart, A. [Irfu/DSM, CEA-Saclay, 91191 Gif/Yvette CEDEX (France); Di Marco, M. [Physics Section, University of Geneva (Switzerland)

    2011-05-01

    The T2K experiment is designed to study neutrino oscillation properties by directing a high intensity neutrino beam produced at J-PARC in Tokai, Japan, towards the large Super-Kamiokande detector located 295 km away, in Kamioka, Japan. The experiment includes a sophisticated near detector complex, 280 m downstream of the neutrino production target in order to measure the properties of the neutrino beam and to better understand neutrino interactions at the energy scale below a few GeV. A key element of the near detectors is the ND280 tracker, consisting of two active scintillator-bar target systems surrounded by three large time projection chambers (TPCs) for charged particle tracking. The data collected with the tracker are used to study charged current neutrino interaction rates and kinematics prior to oscillation, in order to reduce uncertainties in the oscillation measurements by the far detector. The tracker is surrounded by the former UA1/NOMAD dipole magnet and the TPCs measure the charges, momenta, and particle types of charged particles passing through them. Novel features of the TPC design include its rectangular box layout constructed from composite panels, the use of bulk micromegas detectors for gas amplification, electronics readout based on a new ASIC, and a photoelectron calibration system. This paper describes the design and construction of the TPCs, the micromegas modules, the readout electronics, the gas handling system, and shows the performance of the TPCs as deduced from measurements with particle beams, cosmic rays, and the calibration system. - Research highlights: {yields} First large scale time projection chambers with micropattern gas detectors. {yields} Incorporates new ASIC for electronic readout. {yields} Includes a pressure equalizing gas system and a photoelectron calibration system. {yields} Specifications achieved as deduced from neutrino, cosmic, and calibration tests. {yields} Will play an important role in T2K to measure neutrino

  13. Pure Optical Dephasing Dynamics in Semiconducting Single-Walled Carbon Nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Graham, Matt [University of California, Berkeley; Fleming, Graham [University of California, Berkeley; Ma, Yingzhong [ORNL; Green, Alexander A. [Northwestern University, Evanston; Hersam, Mark C. [Northwestern University, Evanston

    2011-01-01

    We report a detailed study of ultrafast exciton dephasing processes in semiconducting single-walled carbon nanotubes (SWNTs) employing a sample highly enriched in a single tube species, the (6,5) tube. Systematic measurements of femtosecond pump-probe, two-pulse photon echo and three-pulse photon echo peak shift over a broad range of excitation intensities and lattice temperature (from 4.4 to 292 K) enable us to quantify the timescales of pure optical dephasing (T 2 ), along with exciton-exciton and exciton-phonon scattering, environmental effects as well as spectral diffusion. While the exciton dephasing time (T2 ) increases from 205 fs at room temperature to 320 fs at 70 K, we found that further decrease of the lattice temperature leads to a shortening of the T2 times. This complex temperature dependence was found to arise from an enhanced relaxation of exciton population at lattice temperatures below 80 K. By quantitatively accounting the contribution from the population relaxation, the corresponding pure optical dephasing times increase monotonically from 225 fs at room temperature to 508 fs at 4.4 K. We further found that below 180 K, the inverse of the pure dephasing time (1/T 2 ) scales linearly with temperature with a slope of 6.7 0.6 eV/K, which suggests dephasing arising from one-phonon scattering (i.e. acoustic phonons). In view ofthe large dynamic disorder of the surrounding environment, the origin of the long room temperature pure dephasing time is proposed to result from reduced strength of exciton-phonon coupling by motional narrowing over nuclear fluctuations. This consideration further suggests the occurrence of remarkable initial exciton delocalization, and makes nanotubes ideal to study many-body effects in spatially confined systems.

  14. High-fidelity gate operations for quantum computing beyond dephasing time limits

    Science.gov (United States)

    Souza, Alexandre M.; Sarthour, Roberto S.; Oliveira, Ivan S.; Suter, Dieter

    2015-12-01

    The implementation of quantum gates with fidelities that exceed the threshold for reliable quantum computing requires robust gates whose performance is not limited by the precision of the available control fields. The performance of these gates also should not be affected by the noisy environment of the quantum register. Here we use randomized benchmarking of quantum gate operations to compare the performance of different families of gates that compensate errors in the control field amplitudes and decouple the system from the environmental noise. We obtain average fidelities of up to 99.8%, which exceeds the threshold value for some quantum error correction schemes as well as the expected limit from the dephasing induced by the environment.

  15. Exploring Dephasing of a Solid-State Quantum Emitter via Time- and Temperature-Dependent Hong-Ou-Mandel Experiments

    Science.gov (United States)

    Thoma, A.; Schnauber, P.; Gschrey, M.; Seifried, M.; Wolters, J.; Schulze, J.-H.; Strittmatter, A.; Rodt, S.; Carmele, A.; Knorr, A.; Heindel, T.; Reitzenstein, S.

    2016-01-01

    We probe the indistinguishability of photons emitted by a semiconductor quantum dot (QD) via time- and temperature-dependent two-photon interference (TPI) experiments. An increase in temporal separation between consecutive photon emission events reveals a decrease in TPI visibility on a nanosecond time scale, theoretically described by a non-Markovian noise process in agreement with fluctuating charge traps in the QD's vicinity. Phonon-induced pure dephasing results in a decrease in TPI visibility from (96 ±4 )% at 10 K to a vanishing visibility at 40 K. In contrast to Michelson-type measurements, our experiments provide direct access to the time-dependent coherence of a quantum emitter on a nanosecond time scale.

  16. Time projection chambers for the T2K near detectors

    Science.gov (United States)

    Abgrall, N.; Andrieu, B.; Baron, P.; Bene, P.; Berardi, V.; Beucher, J.; Birney, P.; Blaszczyk, F.; Blondel, A.; Bojechko, C.; Boyer, M.; Cadoux, F.; Calvet, D.; Catanesi, M. G.; Cervera, A.; Colas, P.; De La Broise, X.; Delagnes, E.; Delbart, A.; Di Marco, M.; Druillole, F.; Dumarchez, J.; Emery, S.; Escudero, L.; Faszer, W.; Ferrere, D.; Ferrero, A.; Fransham, K.; Gaudin, A.; Giganti, C.; Giomataris, I.; Giraud, J.; Goyette, M.; Hamano, K.; Hearty, C.; Henderson, R.; Herlant, S.; Ieva, M.; Jamieson, B.; Jover-Mañas, G.; Karlen, D.; Kato, I.; Konaka, A.; Laihem, K.; Langstaff, R.; Laveder, M.; Le Coguie, A.; Le Dortz, O.; Le Ross, M.; Lenckowski, M.; Lux, T.; Macaire, M.; Mahn, K.; Masciocchi, F.; Mazzucato, E.; Mezzetto, M.; Miller, A.; Mols, J.-Ph.; Monfregola, L.; Monmarthe, E.; Myslik, J.; Nizery, F.; Openshaw, R.; Perrin, E.; Pierre, F.; Pierrepont, D.; Poffenberger, P.; Popov, B.; Radicioni, E.; Ravonel, M.; Reymond, J.-M.; Ritou, J.-L.; Roney, M.; Roth, S.; Sánchez, F.; Sarrat, A.; Schroeter, R.; Stahl, A.; Stamoulis, P.; Steinmann, J.; Terhorst, D.; Terront, D.; Tvaskis, V.; Usseglio, M.; Vallereau, A.; Vasseur, G.; Wendland, J.; Wikström, G.; Zito, M.

    2011-05-01

    The T2K experiment is designed to study neutrino oscillation properties by directing a high intensity neutrino beam produced at J-PARC in Tokai, Japan, towards the large Super-Kamiokande detector located 295 km away, in Kamioka, Japan. The experiment includes a sophisticated near detector complex, 280 m downstream of the neutrino production target in order to measure the properties of the neutrino beam and to better understand neutrino interactions at the energy scale below a few GeV. A key element of the near detectors is the ND280 tracker, consisting of two active scintillator-bar target systems surrounded by three large time projection chambers (TPCs) for charged particle tracking. The data collected with the tracker are used to study charged current neutrino interaction rates and kinematics prior to oscillation, in order to reduce uncertainties in the oscillation measurements by the far detector. The tracker is surrounded by the former UA1/NOMAD dipole magnet and the TPCs measure the charges, momenta, and particle types of charged particles passing through them. Novel features of the TPC design include its rectangular box layout constructed from composite panels, the use of bulk micromegas detectors for gas amplification, electronics readout based on a new ASIC, and a photoelectron calibration system. This paper describes the design and construction of the TPCs, the micromegas modules, the readout electronics, the gas handling system, and shows the performance of the TPCs as deduced from measurements with particle beams, cosmic rays, and the calibration system.

  17. Time Projection Chambers for the T2K Near Detectors

    CERN Document Server

    ,

    2010-01-01

    The T2K experiment is designed to study neutrino oscillation properties by directing a high intensity neutrino beam produced at J-PARC in Tokai, Japan, towards the large Super-Kamiokande detector located 295 km away, in Kamioka, Japan. The experiment includes a sophisticated near detector complex, 280 m downstream of the neutrino production target in order to measure the properties of the neutrino beam and to better understand neutrino interactions at the energy scale below a few GeV. A key element of the near detectors is the ND280 tracker, consisting of two active scintillator-bar target systems surrounded by three large time projection chambers (TPCs) for charged particle tracking. The data collected with the tracker is used to study charged current neutrino interaction rates and kinematics prior to oscillation, in order to reduce uncertainties in the oscillation measurements by the far detector. The tracker is surrounded by the former UA1/Nomad dipole magnet and the TPCs measure the charges, momenta, and ...

  18. Control of dephasing in rotationally hot molecules

    Science.gov (United States)

    Bartram, David; Ivanov, Misha

    2010-04-01

    We consider a rotationally hot diatomic molecule as an example of an open quantum system, where molecular vibrational wave packets are subject to dephasing due to rovibrational coupling. We report analytical and numerical results addressing whether the dephasing rate can be controlled by adjustment of the initial wave packet phases. It appears that over long time scales, phase-only control is not possible, but for earlier time scales the possibility of phase-only control of dephasing remains. In addition, we point out that the time dependence of the dephasing process depends significantly upon the degeneracy of the rotational environment states.

  19. Relaxation and Dephasing in a Two-Electron 13C Nanotube Double Quantum Dot

    DEFF Research Database (Denmark)

    Churchill, H O H; Kuemmeth, Ferdinand; Harlow, J W

    2009-01-01

    We use charge sensing of Pauli blockade (including spin and isospin) in a two-electron 13C nanotube double quantum dot to measure relaxation and dephasing times. The relaxation time T1 first decreases with a parallel magnetic field and then goes through a minimum in a field of 1.4 T. We attribute...... both results to the spin-orbit-modified electronic spectrum of carbon nanotubes, which at high field enhances relaxation due to bending-mode phonons. The inhomogeneous dephasing time T2* is consistent with previous data on hyperfine coupling strength in 13C nanotubes....

  20. Estimation of T2 relaxation time of breast cancer: Correlation with clinical, imaging and pathological features

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Mirinae; Sohn, Yu Mee [Dept. of Radiology, Kyung Hee University Hospital, College of Medicine, Kyung Hee University, Seoul (Korea, Republic of); Ryu, Jung Kyu; Jahng, Geon Ho; Rhee, Sun Jung; Oh, Jang Hoon; Won, Kyu Yeoun [Kyung Hee University Hospital at Gangdong, College of Medicine, Kyung Hee University, Seoul (Korea, Republic of)

    2017-01-15

    The purpose of this study was to estimate the T2* relaxation time in breast cancer, and to evaluate the association between the T2* value with clinical-imaging-pathological features of breast cancer. Between January 2011 and July 2013, 107 consecutive women with 107 breast cancers underwent multi-echo T2*-weighted imaging on a 3T clinical magnetic resonance imaging system. The Student's t test and one-way analysis of variance were used to compare the T2* values of cancer for different groups, based on the clinical-imaging-pathological features. In addition, multiple linear regression analysis was performed to find independent predictive factors associated with the T2* values. Of the 107 breast cancers, 92 were invasive and 15 were ductal carcinoma in situ (DCIS). The mean T2* value of invasive cancers was significantly longer than that of DCIS (p = 0.029). Signal intensity on T2-weighted imaging (T2WI) and histologic grade of invasive breast cancers showed significant correlation with T2* relaxation time in univariate and multivariate analysis. Breast cancer groups with higher signal intensity on T2WI showed longer T2* relaxation time (p = 0.005). Cancer groups with higher histologic grade showed longer T2* relaxation time (p = 0.017). The T2* value is significantly longer in invasive cancer than in DCIS. In invasive cancers, T2* relaxation time is significantly longer in higher histologic grades and high signal intensity on T2WI. Based on these preliminary data, quantitative T2* mapping has the potential to be useful in the characterization of breast cancer.

  1. Quantitative t2 values predict time from symptom onset in acute stroke patients

    DEFF Research Database (Denmark)

    Siemonsen, Susanne; Mouridsen, Kim; Holst, Brigitte

    2009-01-01

    BACKGROUND AND PURPOSE: We hypothesize that in comparison to diffusion-weighted imaging, quantitative T2 values (qT2) are more directly related to water uptake in ischemic tissue, depending on time from symptom onset. We measured the increase of qT2 in the infarct core to quantify the correlation...

  2. Dephasing and hyperfine interaction in carbon nanotubes double quantum dots

    DEFF Research Database (Denmark)

    Reynoso, Andres Alejandro; Flensberg, Karsten

    2012-01-01

    We study theoretically the return probability experiment, which is used to measure the dephasing time T-2*, in a double quantum dot (DQD) in semiconducting carbon nanotubes with spin-orbit coupling and disorder-induced valley mixing. Dephasing is due to hyperfine interaction with the spins of the C......-13 nuclei. Due to the valley and spin degrees of freedom, four bounded states exist for any given longitudinal mode in the quantum dot. At zero magnetic field, the spin-orbit coupling and the valley mixing split those four states into two Kramers doublets. The valley-mixing term for a given dot...... is determined by the intradot disorder; this leads to (i) states in the Kramers doublets belonging to different dots being different, and (ii) nonzero interdot tunneling amplitudes between states belonging to different doublets. We show that these amplitudes give rise to new avoided crossings, as a function...

  3. T2 star relaxation times for assessment of articular cartilage at 3 T: a feasibility study.

    Science.gov (United States)

    Mamisch, Tallal Charles; Hughes, Timothy; Mosher, Timothy J; Mueller, Christoph; Trattnig, Siegfried; Boesch, Chris; Welsch, Goetz Hannes

    2012-03-01

    T2 mapping techniques use the relaxation constant as an indirect marker of cartilage structure, and the relaxation constant has also been shown to be a sensitive parameter for cartilage evaluation. As a possible additional robust biomarker, T2* relaxation time is a potential, clinically feasible parameter for the biochemical evaluation of articular cartilage. The knees of 15 healthy volunteers and 15 patients after microfracture therapy (MFX) were evaluated with a multi-echo spin-echo T2 mapping technique and a multi-echo gradient-echo T2* mapping sequence at 3.0 Tesla MRI. Inline maps, using a log-linear least squares fitting method, were assessed with respect to the zonal dependency of T2 and T2* relaxation for the deep and superficial regions of healthy articular cartilage and cartilage repair tissue. There was a statistically significant correlation between T2 and T2* values. Both parameters demonstrated similar spatial dependency, with longer values measured toward the articular surface for healthy articular cartilage. No spatial variation was observed for cartilage repair tissue after MFX. Within this feasibility study, both T2 and T2* relaxation parameters demonstrated a similar response in the assessment of articular cartilage and cartilage repair tissue. The potential advantages of T2*-mapping of cartilage include faster imaging times and the opportunity for 3D acquisitions, thereby providing greater spatial resolution and complete coverage of the articular surface.

  4. T2 star relaxation times for assessment of articular cartilage at 3 T: a feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Mamisch, Tallal Charles [University Bern, Department of Orthopedic Surgery, Inselspital, Bern (Switzerland); University Bern, Magnetic Resonance Spectroscopy and Methodology, Department of Clinical Research, Bern (Switzerland); Hughes, Timothy [Siemens Medical Solutions, Erlangen (Germany); Mosher, Timothy J. [Penn State University College of Medicine, Musculoskeletal Imaging and MRI, Department of Radiology, Hershey, PA (United States); Mueller, Christoph [University of Erlangen, Department of Trauma Surgery, Erlangen (Germany); Trattnig, Siegfried [Medical University of Vienna, MR Center - High Field MR, Department of Radiology, Vienna (Austria); Boesch, Chris [University Bern, Magnetic Resonance Spectroscopy and Methodology, Department of Clinical Research, Bern (Switzerland); Welsch, Goetz Hannes [University of Erlangen, Department of Trauma Surgery, Erlangen (Germany); Medical University of Vienna, MR Center - High Field MR, Department of Radiology, Vienna (Austria)

    2012-03-15

    T2 mapping techniques use the relaxation constant as an indirect marker of cartilage structure, and the relaxation constant has also been shown to be a sensitive parameter for cartilage evaluation. As a possible additional robust biomarker, T2* relaxation time is a potential, clinically feasible parameter for the biochemical evaluation of articular cartilage. The knees of 15 healthy volunteers and 15 patients after microfracture therapy (MFX) were evaluated with a multi-echo spin-echo T2 mapping technique and a multi-echo gradient-echo T2* mapping sequence at 3.0 Tesla MRI. Inline maps, using a log-linear least squares fitting method, were assessed with respect to the zonal dependency of T2 and T2* relaxation for the deep and superficial regions of healthy articular cartilage and cartilage repair tissue. There was a statistically significant correlation between T2 and T2* values. Both parameters demonstrated similar spatial dependency, with longer values measured toward the articular surface for healthy articular cartilage. No spatial variation was observed for cartilage repair tissue after MFX. Within this feasibility study, both T2 and T2* relaxation parameters demonstrated a similar response in the assessment of articular cartilage and cartilage repair tissue. The potential advantages of T2*-mapping of cartilage include faster imaging times and the opportunity for 3D acquisitions, thereby providing greater spatial resolution and complete coverage of the articular surface. (orig.)

  5. T2 relaxation time mapping of the cartilage cap of osteochondromas

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hee Kyung; Horn, Paul; Laor, Tal [Cincinnati Children' s Hospital Medical Center, Cincinnati (United States); Daedzinski, Bernard J. [Dept. of Radiology, Children' s Hospital of Philadelphia, University of Pennsylvania, Philadelphia (United States); Kim, Dong Hoon [Dept. of Radiology, Pharmacology, Korea University College of Medicine, Seoul (Korea, Republic of)

    2016-02-15

    Our aim was to evaluate the cartilage cap of osteochondromas using T2 maps and to compare these values to those of normal patellar cartilage, from age and gender matched controls. This study was approved by the Institutional Review Board and request for informed consent was waived. Eleven children (ages 5-17 years) with osteochondromas underwent MR imaging, which included T2-weighted fat suppressed and T2 relaxation time mapping (echo time = 9-99/repetition time = 1500 msec) sequences. Lesion origins were femur (n = 5), tibia (n = 3), fibula (n = 2), and scapula (n = 1). Signal intensity of the cartilage cap, thickness, mean T2 relaxation times, and T2 spatial variation (mean T2 relaxation times as a function of distance) were evaluated. Findings were compared to those of patellar cartilage from a group of age and gender matched subjects. The cartilage caps showed a fluid-like high T2 signal, with mean thickness of 4.8 mm. The mean value of mean T2 relaxation times of the osteochondromas was 264.0 ± 80.4 msec (range, 151.0-366.0 msec). Mean T2 relaxation times were significantly longer than the values from patellar cartilage (39.0 msec) (p < 0.0001). These findings were observed with T2 spatial variation plots across the entire distance of the cartilage cap, with the most pronounced difference in the middle section of the cartilage. Longer T2 relaxation times of the cartilage caps of osteochondromas should be considered as normal, and likely to reflect an increased water content, different microstructure and component.

  6. Influence of collisional dephasing processes on superfluorescence

    Science.gov (United States)

    Maki, Jeffery J.; Malcuit, Michelle S.; Raymer, Michael G.; Boyd, Robert W.; Drummond, Peter D.

    1989-11-01

    We present a quantum-mechanical treatment of the influence of collisional dephasing processes on the statistical properties of superfluorescence (SF). The theory, which treats nonlinear propagation effects as well as quantum noise, shows how the nature of the cooperative emission process changes from that of SF to that of amplified spontaneous emission as the collisional dephasing rate is varied. The predictions of how the SF delay time varies with the collisional dephasing rate are in good agreement with the results of a recent experiment [M. S. Malcuit, J. J. Maki, D. J. Simkin, and R. W. Boyd, Phys. Rev. Lett. 59, 1189 (1987)].

  7. Determination of T1- and T2-relaxation times in the spleen of patients with splenomegaly

    DEFF Research Database (Denmark)

    Thomsen, C; Josephsen, P; Karle, H

    1990-01-01

    Twenty-nine patients with known splenomegaly and seven healthy volunteers were examined. The T1 and T2 relaxation times were read out from a region of interest centrally in the spleen. Even though different mean T1 and T2 relaxation times were found between the groups, the great scatter and the c...... and the considerable overlap between the groups makes the contribution of relaxation time measurements to the differential diagnosis of splenomegaly of limited value....

  8. T(2) relaxation time of hyaline cartilage in presence of different gadolinium-based contrast agents.

    Science.gov (United States)

    Wiener, Edzard; Settles, Marcus; Diederichs, Gerd

    2010-01-01

    The transverse relaxation time, T(2), of native cartilage is used to quantify cartilage degradation. T(2) is frequently measured after contrast administration, assuming that the impact of gadolinium-based contrast agents on cartilage T(2) is negligible. To verify this assumption the depth-dependent variation of T(2) in the presence of gadopentetate dimeglumine, gadobenate dimeglumine and gadoteridol was investigated. Furthermore, the r(2)/r(1) relaxivity ratios were quantified in different cartilage layers to demonstrate differences between T(2) and T(1) relaxation effects. Transverse high-spatial-resolution T(1)- and T(2)-maps were simultaneously acquired on a 1.5 T MR scanner before and after contrast administration in nine bovine patellae using a turbo-mixed sequence. The r(2)/r(1) ratios were calculated for each contrast agent in cartilage. Profiles of T(1), T(2) and r(2)/r(1) across cartilage thickness were generated in the absence and presence of contrast agent. The mean values in different cartilage layers were compared for global variance using the Kruskal-Wallis test and pairwise using the Mann-Whitney U-test. T(2) of unenhanced cartilage was 98 +/- 5 ms at 1 mm and 65 +/- 4 ms at 3 mm depth. Eleven hours after contrast administration significant differences (p cartilage thickness were close to 1.0 (range 0.9-1.3). At 1.5 T, T(2) decreased significantly in the presence of contrast agents, more pronounced in superficial than in deep cartilage. The change in T(2) relaxation rate was similar to the change in T(1). Cartilage T(2) measurements after contrast administration will lead to systematic errors in the quantification of cartilage degradation. 2010 John Wiley & Sons, Ltd.

  9. Accuracy validation of T2L2 time transfer in co-location.

    Science.gov (United States)

    Laas-Bourez, Myrtille; Courde, Clément; Samain, Etienne; Exertier, Pierre; Guillemot, Philippe; Torre, Jean-Marie; Martin, Nicolas; Foussard, Claude

    2015-02-01

    The Time Transfer by Laser Link (T2L2) experiment has been developed in close collaboration between Centre National d'Etudes Spatiales and Observatoire de la Côte d'Azur. The aim is to synchronize remote ultra-stable clocks over large-scale distances using two laser ranging stations. This ground to space time transfer has been derived from laser telemetry technology with dedicated space equipment designed to record arrival time of laser pulses on board the satellite. For 3 years, specific campaigns have been organized to prove T2L2 performance. In April 2012, we performed a 2-week campaign with our two laser ranging stations, Métrologie Optique and French Transportable Laser Ranging Station, to demonstrate the T2L2 time transfer accuracy in co-location. We have compared three independent time transfer techniques: T2L2, GPS, and direct measurement, with both an event timer and an interval counter. The most important result obtained in this campaign was a mean agreement between T2L2 and a direct comparison better than 200 ps. This is the first major step to validate the uncertainty budget of the entire T2L2 experiment. This paper focuses on this campaign setup and the obtained results.

  10. Intracerebral pH affects the T2 relaxation time of brain tissue

    Energy Technology Data Exchange (ETDEWEB)

    Schilling, A.M.; Blankenburg, F.B.; Bernarding, J.; Heidenreich, J.O.; Wolf, K.J. [Department of Radiology, University Hospital Benjamin Franklin, Free University Berlin, Hindenburgdamm 30, 12200 Berlin (Germany)

    2002-12-01

    Signal changes in activated brain areas are detectable by MRI and MR spectroscopy (MRS). Shifts in pH occur during brain activation. Our aim was to investigate the relationship between changes in pH and T2 relaxation times. T2 was determined in vitro at 24 MHz in various liquids at different pH using a Carr-Purcell-Meiboom-Gill (CPMG) spin-echo sequence. We also studied five Fisher rats were studied at 2.4 tesla with a double-tuneable surface coil. After baseline measurements, potassium cyanide was injected, producing intracerebral acidosis. Alternating series of 1H CPMG spin-echo sequences and 31P spectra were acquired. True T2 relaxation times were calculated from a CPMG multi-echo train. Changes in intracellular pH determined from 31P spectra. In vitro measurements demonstrated a correlation between T2 and pH that could be described by a quadratic fit curve. Depending on the initial pH, changes of 0.2 induced changes in T2 of up to 150 ms. In vivo measurements confirmed these findings. After intraperitoneal injection of a sublethal dose of cyanide, T2 decreased by about 5% in four cases, followed by recovery after 2 h. The in vitro measurements demonstrated that changes in pH can lead to significant signal change on T2- or T2*- weighted images. The dependence of T2 on pH in vitro was confirmed in vivo; it may contribute to signal change in activated brain areas. (orig.)

  11. In-vivo T2-relaxation times of asymptomatic cervical intervertebral discs

    Energy Technology Data Exchange (ETDEWEB)

    Driscoll, Sean J.; Mao, Haiqing; Li, Guoan [Massachusetts General Hospital/Harvard Medical School, Bioengineering Laboratory, Department of Orthopaedic Surgery, Boston, MA (United States); Zhong, Weiye [Massachusetts General Hospital/Harvard Medical School, Bioengineering Laboratory, Department of Orthopaedic Surgery, Boston, MA (United States); Second Xiangya Hospital and Central South University, Department of Spinal Surgery, Changsha, Hunan (China); Torriani, Martin [Massachusetts General Hospital/Harvard Medical School, Musculoskeletal Imaging and Intervention, Department of Radiology, Boston, MA (United States); Wood, Kirkham B.; Cha, Thomas D. [Massachusetts General Hospital/Harvard Medical School, Spine Service, Department of Orthopaedic Surgery, Boston, MA (United States)

    2016-03-15

    Limited research exists on T2-mapping techniques for cervical intervertebral discs and its potential clinical utility. The objective of this research was to investigate the in-vivo T2-relaxation times of cervical discs, including C2-C3 through C7-T1. Ten asymptomatic subjects were imaged using a 3.0 T MR scanner and a sagittal multi-slice multi-echo sequence. Using the mid-sagittal image, intervertebral discs were divided into five regions-of-interest (ROIs), centered along the mid-line of the disc. Average T2 relaxation time values were calculated for each ROI using a mono-exponential fit. Differences in T2 values between disc levels and across ROIs of the same disc were examined. For a given ROI, the results showed a trend of increasing relaxation times moving down the spinal column, particularly in the middle regions (ROIs 2, 3 and 4). The C6-C7 and C7-T1 discs had significantly greater T2 values compared to superior discs (discs between C2 and C6). The results also showed spatial homogeneity of T2 values in the C3-C4, C4-C5, and C5-C6 discs, while C2-C3, C6-C7, and C7-T1 showed significant differences between ROIs. The findings indicate there may be inherent differences in T2-relaxation time properties between different cervical discs. Clinical evaluations utilizing T2-mapping techniques in the cervical spine may need to be level-dependent. (orig.)

  12. Discrimination of benign from malignant hepatic lesions based on their T2-relaxation times calculated from moderately T2-weighted turbo SE sequence

    Energy Technology Data Exchange (ETDEWEB)

    Cieszanowski, Andrzej; Szeszkowski, Wojciech; Golebiowski, Marek; Bielecki, Dennis K.; Pruszynski, Bogdan [2. Department of Clinical Radiology, Medical University of Warsaw, ul.Banacha 1a, 02097, Warsaw (Poland); Grodzicki, Mariusz [Department of Surgery and Liver Disease, Medical University of Warsaw, ul.Banacha 1a, 02097, Warsaw (Poland)

    2002-09-01

    The differentiation of hemangioma from other hepatic neoplasms using MRI usually relies on the evaluation of heavily T2-weighted images. The aim of this study was to assess the value of T2-relaxation times calculated from moderately T2-weighted turbo spin-echo (TSE) sequence in characterization of focal hepatic lesions, including hepatic malignancies, focal nodular hyperplasia (FNH), hemangioma, and cyst. Fifty-two patients with 114 proven lesions (61 malignant masses, 6 focal nodular hyperplasias, 28 hemangiomas, 19 cystic lesions) were examined on 1.5-T system using a double-echo TSE sequence (TR=1800 ms; TE{sub eff} 1=40 ms; TE{sub eff} 2=120 ms). Signal intensities (SI) of the liver as well as SI of all lesions were measured, and then the T2-relaxation times were calculated. The mean T2 time for the liver was 54 ms ({+-}8 ms), for FNH 66 ms ({+-}7 ms), for malignant hepatic lesions 85 ms ({+-}17 ms), for hemangiomas 155 ms ({+-}35 ms), and for cystic lesions 583 ms ({+-}369) ms. Most malignant hepatic lesions were best differentiated between the thresholds of 67 and 116 ms, generating a sensitivity of 90% and a specificity of 94%. There were six false-negative diagnoses of malignant tumor and three false-positive cases (two hemangiomas and one FNH). Calculation of the T2-relaxation times obtained from the double-echo TSE sequence with moderate T2-weighting allowed differentiation between malignant and benign hepatic lesions with high sensitivity and specificity. (orig.)

  13. Statistical Time-Frequency Multiplexing of HD Video Traffic in DVB-T2

    Directory of Open Access Journals (Sweden)

    Mehdi Rezaei

    2009-01-01

    Full Text Available Digital video broadcast-terrestrial 2 (DVB-T2 is the successor of DVB-T standard that allows a two-dimensional multiplexing of broadcast services in time and frequency domains. It introduces an optional time-frequency slicing (TFS transmission scheme to increase the flexibility of service multiplexing. Utilizing statistical multiplexing (StatMux in conjunction with TFS is expected to provide a high performance for the broadcast system in terms of resource utilization and quality of service. In this paper, a model for high-definition video (HDV traffic is proposed. Then, utilizing the proposed model, the performance of StatMux of HDV broadcast services over DVB-T2 is evaluated. Results of the study show that implementation of StatMux in conjunction with the newly available features in DVB-T2 provides a high performance for the broadcast system.

  14. Activated and non-activated dephasing in a spin bath

    Science.gov (United States)

    Torrontegui, E.; Kosloff, R.

    2016-09-01

    We analyze different decoherence processes in a system coupled to a bath. Apart from the well known standard dephasing mechanism which is temperature dependent an alternative mechanism is presented, the spin-swap dephasing which does not need initial bath activation and is temperature independent. We show that for dipole interaction in the weak coupling regime the separation of time scales between system and bath can not produce pure dephasing, the process being accompanied by dissipation. Activated and non-activated dephasing processes are analyzed in a diamond nitrogen-vacancy center.

  15. Time transfer by laser link (T2L2): characterization and calibration of the flight instrument

    Science.gov (United States)

    Samain, E.; Vrancken, P.; Guillemot, P.; Fridelance, P.; Exertier, P.

    2014-10-01

    The T2L2 project (time transfer by laser link) allows for the synchronization of remote ultra-stable clocks over intercontinental distances (Fridelance et al 1997 Exp. Astron. 7, Samain and Fridelance 1998 Metrologia 35 151-9). The principle is derived from satellite laser ranging technology with dedicated space equipment designed to record arrival times of laser pulses at the satellite. The space segment has been launched in June 2008 as a passenger experiment on the ocean altimetry satellite Jason 2. T2L2 had been specified to yield a time stability of better than 1 ps over 1000 s integration time and an accuracy of better than 100 ps. This level of performance requires a rigorous data processing which can be performed only with a comprehensive calibration model of the whole instrumentation. For this purpose, several experimental measurements have been performed before and during the integration phase of the T2L2 space instrument. This instrument model is one of the cornerstones of the data reduction process which is carried out to translate the raw information to a usable picosecond time transfer. After providing a global synopsis of the T2L2 space instrument, the paper gives a description of the experimental setup for the instrument characterization. It then details the different contributions within the calibration model and concludes with an applied example of a space to ground time transfer.

  16. Time Transfer by Laser Link - T2L2: Results of the First Year of Operation

    Science.gov (United States)

    2009-11-01

    have demonstrated noise levels of some tens of picoseconds and a preliminary time stability of a few picoseconds over integration times of some tens ...satellite clocks (the ultra-stable oscillator USO of DORIS in the case of Jason-2) to be synchronized are linked to a laser station and to the T2L2...possible to compute a synthetic time of flight obtained over an integration duration of few tens of seconds. This method is pertinent in two cases

  17. DC Magnetometry at the $T_2$ Limit

    CERN Document Server

    Ajoy, A; Cappellaro, P

    2016-01-01

    Sensing static or slowly varying magnetic fields with high sensitivity and spatial resolution is critical to many applications in fundamental physics, bioimaging and materials science. Several versatile magnetometry platforms have emerged over the past decade, such as electronic spins associated with Nitrogen Vacancy (NV) centers in diamond. However, their high sensitivity to external fields also makes them poor sensors of DC fields. Indeed, the usual method of Ramsey magnetometry leaves them prone to environmental noise, limiting the allowable interrogation time to the short dephasing time T2*. Here we introduce a hybridized magnetometery platform, consisting of a sensor and ancilla, that allows sensing static magnetic fields with interrogation times up to the much longer T2 coherence time, allowing significant potential gains in field sensitivity. While more generally applicable, we demonstrate the method for an electronic NV sensor and a nuclear ancilla. It relies on frequency upconversion of transverse DC...

  18. Dephasing in InAs/GaAs quantum dots

    DEFF Research Database (Denmark)

    Borri, Paola; Langbein, Wolfgang Werner; Mørk, Jesper;

    1999-01-01

    The room-temperature dephasing in InAs/GaAs self-assembled quantum dots is measured using two independent methods: spectal-hole burning and four-wave mixing. Dephasing times weakly dependent on the excitation density are found, with a low density value of 290+/-80 fs from spectal-hole burning...

  19. T2-Filtered T2 - T2 Exchange NMR

    Science.gov (United States)

    d'Eurydice, Marcel Nogueira; Montrazi, Elton Tadeu; Fortulan, Carlos Alberto; Bonagamba, Tito José

    2016-05-01

    This work introduces an alternative way to perform the T2 - T2 Exchange NMR experiment. Rather than varying the number of π pulses in the first CPMG cycle of the T2 - T2 Exchange NMR pulse sequence, as used to obtain the 2D correlation maps, it is fixed and small enough to act as a short T2-filter. By varying the storage time, a set of 1D measurements of T2 distributions can be obtained to reveal the effects of the migration dynamics combined with relaxation effects. This significantly reduces the required time to perform the experiment, allowing a more in-depth study of exchange dynamics and relaxation processes with improved signal-to-noise ratio. These aspects stand as basis of this novel experiment, T2-Filtered T2 - T2 Exchange NMR or simply T2 F-TREx.

  20. ${\\cal N}=2$ heterotic string compactifications on orbifolds of $K3\\times T^2$

    CERN Document Server

    Chattopadhyaya, Aradhita

    2016-01-01

    We study ${\\cal N}=2$ compactifications of $E_8\\times E_8$ heterotic string theory on orbifolds of $K3 \\times T^2$ by $g'$ which acts as an $\\mathbb{Z}_N$ automorphism of $K3$ together with a$1/N$ shift on a circle of $T^2$. The orbifold action $g'$ corresponds to the $26$ conjugacy classes of the Mathieu group $M_{24}$. We show that for the standard embedding the new supersymmetric index for these compactifications can always be decomposed into the elliptic genus of $K3$ twisted by $g'$. The difference in one-loop corrections to the gauge couplings are captured by automorphic forms obtained by the theta lifts of the elliptic genus of $K3$ twisted by $g'$. We work out in detail the case for which $g'$ belongs to the equivalence class $2B$. We then investigate all the non-standard embeddings for$K3$ realized as a $T^4/\\mathbb{Z}_\

  1. Proposal for an Extended Run of T2K to $20\\times10^{21}$ POT

    CERN Document Server

    Abe, K; Amji, A; Amey, J; Andreopoulos, C; Antonova, M; Aoki, S; Atherton, A; Ban, S; Barbato, F C T; Barbi, M; Barbato, F C T; Barker, G J; Barr, G; Bartet-Friburg, P; Batkiewicz, M; Berardi, V; Bhadra, S; Bienstock, S; Blondel, A; Bolognesi, S; Bordoni, S; Boyd, S B; Brailsford, D; Bravar, A; Bronner, C; Avanzini, M Buizza; Calcutt, J; Calland, R G; Calvet, D; Campbell, T; Cao, S; Cartwright, S L; Castillo, R; Catanesi, M G; Cervera, A; Checchia, C; Cherdack, D; Chikuma, N; Christodoulou, G; Clifton, A; Coleman, J; Collazuol, G; Coplowe, D; Cremonesi, L; Cudd, A; Dabrowska, A; Delbart, A; De Rosa, G; Dealtry, T; Denner, P F; Dennis, S R; Densham, C; Dewhurst, D; Di Lodovico, F; Dolan, S; Drapier, O; Duffy, K E; Dumarchez, J; Dunkman, M; Dziewiecki, M; Emery-Schrenk, S; Fernanddez, P; Feusels, T; Finch, A J; Fiorentini, G A; Fiorillo, G; Fitton, M; Friend, M; Fujii, Y; Fukuda, D; Fukuda, Y; Garcia, A; Giganti, C; Gizzarelli, F; Gonin, M; Grant, N; Hadley, D R; Haegel, L; Haigh, M D; Hansen, D; Harada, J; Hartz, M; Hasegawa, T; Hastings, N C; Hayashino, T; Hayato, Y; Hiraki, T; Hiramoto, A; Hirota, S; Hogan, M; Holeczek, J; Hosomi, F; Huang, K; Ichikawa, A K; Ikeda, M; Imber, J; Insler, J; Intonti, R A; Ishida, T; Ishii, T; Iwai, E; Iwamoto, K; Izmaylov, A; Jamieson, B; Jiang, M; Johnson, S; Jo, J H; Jonsson, P; Jung, C K; Kabirnezhad, M; Kaboth, A C; Kajita, T; Kakuno, H; Kameda, J; Katori, T; Kearns, E; Khabibullin, M; Khotjantsev, A; Kim, H; King, S; Kisiel, J; Knight, A; Knox, A; Kobayashi, T; Koch, L; Koga, T; Konaka, A; Kondo, K; Kormos, L L; Korzenev, A; Koshio, Y; Kowalik, K L; Kropp, W; Kudenko, Y; Kurjata, R; Kutter, T; Labarga, L; Lagoda, J; Lamont, I; Lamoureux, M; Larkin, E; Lasorak, P; Laveder, M; Lawe, M; Lindner, T; Liptak, Z J; Litchfield, R P; Li, X; Longhin, A; Lopez, J P; Lou, T; Ludovici, L; Lu, X; Magaletti, L; Mahn, K; Malek, M; Manly, S; Marino, A D; Martin, J F; Martins, P; Martynenko, S; Maruyama, T; Matveev, V; Mavrokoridis, K; Ma, W Y; Mazzucato, E; McCarthy, M; McCauley, N; McFarland, K S; McGrew, C; Mefodiev, A; Metelko, C; Mezzetto, M; Mijakowski, P; Minamino, A; Mineev, O; Mine, S; Missert, A; Miura, M; Moriyama, S; Mueller, Th A; Nagai, Y; Nakadaira, T; Nakahata, M; Nakamura, K G; Nakamura, K; Nakamura, K D; Nakanishi, Y; Nakayama, S; Nakaya, T; Nakayoshi, K; Nantais, C; Nishikawa, K; Nishimura, Y; Novella, P; Nowak, J; O'Keeffe, H M; Ohta, R; Okumura, K; Okusawa, T; Ovsyannikova, T; Owen, R A; Oyama, Y; Palladino, V; Palomino, J L; Paolone, V; Parker, W; Patel, N D; Pavin, M; Payne, D; Perkin, J D; Pickard, L; Pickering, L; Guerra, E S Pinzon; Popov, B; Posiadala-Zezula, M; Poutissou, J -M; Poutissou, R; Przewlocki, P; Quilain, B; Radermacher, T; Radicioni, E; Ratoff, P N; Ravonel, M; Rayner, M A; Reinherz-Aronis, E; Riccio, C; Rojas, P; Rondio, E; Rossi, B; Roth, S; Ruggeri, A C; Rychter, A; Sacco, R; Sakashita, K; Sánchez, F; Scantamburlo, E; Scholberg, K; Schwehr, J; Scott, M; Seiya, Y; Sekiguchi, T; Sekiya, H; Sgalaberna, D; Shah, R; Shaikhiev, A; Shaker, F; Shaw, D; Shiozawa, M; Shirahige, T; Short, S; Smy, M; Sobczyk, J T; Sobel, H; Southwell, L; Steinmann, J; Stewart, T; Stowell, P; Suda, Y; Suvorov, S; Suzuki, A; Suzuki, S Y; Suzuki, Y; Szeptycka, M; Tacik, R; Tada, M; Takeda, A; Takeuchi, Y; Tamura, R; Tanaka, H K; Tanaka, H A; Terhorst, D; Terri, R; Thakore, T; Thompson, L F; Toki, W; Tomura, T; Touramanis, C; Tsukamoto, T; Tzanov, M; Uchida, M A; Uchida, Y; Vagins, M; Vacheret, A; Vallari, Z; Vasseur, G; Wachala, T; Walter, C W; Wark, D; Wascko, M O; Weber, A; Wendell, R; Wilkes, R J; Wilking, M J; Wilson, J R; Wilson, R J; Wret, C; Yamada, Y; Yamamoto, K; Yamamoto, M; Yanagisawa, C; Yano, T; Yen, S; Yershov, N; Yokoyama, M; Yoo, J; Yoshida, K; Yuan, T; Yu, M; Zalewska, A; Zalipska, J; Zambelli, L; Zaremba, K; Ziembicki, M; Zimmerman, E D; Zito, M

    2016-01-01

    Recent measurements by the T2K neutrino oscillation experiment indicate that CP violation in neutrino mixing may be observed in the future by long-baseline neutrino oscillation experiments. We propose an extension to the currently approved T2K running from $7.8\\times 10^{21}~\\mbox{POT}$ to $20\\times 10^{21}~\\mbox{POT}$, aiming at initial observation of CP violation with 3$\\,\\sigma$ or higher significance for the case of maximum CP violation. The program also contains a measurement of mixing parameters, $\\theta_{23}$ and $\\Delta m^2_{32}$, with a precision of 1.7$^\\circ$ or better and 1%, respectively. With accelerator and beamline upgrades, as well as analysis improvements, this program would occur before the next generation of long-baseline neutrino oscillation experiments that are expected to start operation in 2026.

  2. Time Transfer by Laser Link The T2L2 Experiment on Jason-2

    Science.gov (United States)

    Samain, E.; Weick, J.; Vrancken, P.; Torre, J.-M.; Mangin, J.-F.; Para, F.; Paris, J.; Albanese, D.; Dalla, R.; Guillemot, Ph.; Petitbon, I.

    2006-06-01

    The new generation of optical time transfer will allow the synchronization of remote ultra stable clocks and the determination of their performances over intercontinental distances. The principle of T2L2 (Time Transfer by Laser Link) is based on laser ranging technique coupled with time-frequency metrology and consists in synchronizing ground and space clocks using short light pulses traveling between the ground and a satellite. The instrument will be integrated to the Jason-2 altimetric satellite billed for launch in 2008. The experiment should enhance the performances of time transfer by one or two magnitudes as compared to existing microwave techniques like GPS and Two-Way.

  3. Design and test of the time transfer by laser link (T2L2) optical subsystem

    Science.gov (United States)

    Vrancken, Patrick; Samain, Etienne; Guillemot, Philippe

    2008-04-01

    We report on the design and test of the optical subsystem of the T2L2 (Time Transfer by Laser Link) space instrument. The T2L2 experiment, developed by OCA and CNES is a next generation optical time transfer system that will allow an improvement1,2 by one to two orders of magnitude as compared to the performances of existing microwave time transfer systems like GPS or Two-Way. The principle is derived from satellite laser ranging (SLR) technology with dedicated space equipment embarked on the satellite Jason 2, scheduled for launch in mid-2008. Satellite Laser Ranging stations (connected to the clocks to be synchronized) emit short laser pulses towards the satellite where they are equally reflected and dated by an onboard event timer. The departure and return of the laser pulses are also timed in the laser stations. The time transfer is derived aposteriori from the data triplets (departure, satellite, return) acquired on the satellite and the respective laser stations. The T2L2 instrument consists of an optical and an electronic subsystem. The optical subsystem is designed such that its field of view (FOV) covers the whole earth for the Jason 2 orbit. It features a linear and a non-linear channel consisting of optical elements and avalanche photodiodes; the linear channel's purpose is threefold: it triggers the whole timing system and measures both the background light and the laser pulse energy. The non-linear channel is for precise timing. We report on the detailed construction of the optical assembly and an exhaustive calibration and performance test campaign in terms of metrology. This test campaign was performed in the clean-room facilities at CNES, Toulouse in March/April 2007 with a dedicated test bed featuring a mode locked laser, variable geometry for different incidence angles and a reference timing system.

  4. Model discrimination for dephasing two-level systems

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Er-ling [Department of Automatic Control, College of Mechatronic Engineering and Automation, National University of Defense Technology, Changsha, Hunan 410073 (China); College of Science (Physics), Swansea University, Singleton Park, Swansea, SA2 8PP (United Kingdom); Zhou, Weiwei [Department of Automatic Control, College of Mechatronic Engineering and Automation, National University of Defense Technology, Changsha, Hunan 410073 (China); Schirmer, Sophie, E-mail: sgs29@swan.ac.uk [College of Science (Physics), Swansea University, Singleton Park, Swansea, SA2 8PP (United Kingdom)

    2015-02-06

    The problem of model discriminability and parameter identifiability for dephasing two-level systems subject to Hamiltonian control is studied. Analytic solutions of the Bloch equations are used to derive explicit expressions for observables as functions of time for different models. This information is used to give criteria for model discrimination and parameter estimation based on simple experimental paradigms. - Highlights: • Analytic expressions for observables of driven, dephasing two-level systems. • Distinguishability of dephasing models via Rabi-oscillation experiments. • General identifiability of model parameters and cases of failure. • Application to empirically determine of effect of driving on dephasing basis. • Importance for optimal design of coherent controls for qubits subject to dephasing.

  5. Coherent Detection of Electron Dephasing

    NARCIS (Netherlands)

    Strambini, E.; Chirolli, L.; Giovanetti, V.; Taddei, F.; Fazio, R.; Piazza, V.

    2010-01-01

    We show that an Aharonov-Bohm ring with asymmetric electron injection can act as a coherent detector of electron dephasing. The presence of a dephasing source in one of the two arms of a moderately-to-highly asymmetric ring changes the response of the system from total reflection to complete transmi

  6. Integrable KdV Hierarchies on $T^2=S^1\\times S^1$

    CERN Document Server

    Sedra, M B

    2007-01-01

    Following our previous works on extended higher spin symmetries on the torus we focus in the present contribution to make a setup of the integrable KdV hierarchies on $T^{2} = S^{1} \\times S^{1}$. Actually two particular systems are considered, namely the KdV and the Burgers non linear integrable model associated to currents of conformal weights (2, 2) and (1, 1) respectively. One key steps towards proving the integrability of these systems is to find their Lax pair operators. This is explicitly done and a mapping between the two systems is discussed.

  7. Room-Temperature Dephasing in InAs Quantum Dots

    DEFF Research Database (Denmark)

    Borri, Paola; Langbein, Wolfgang; Mørk, Jesper;

    2000-01-01

    The room temperature dephasing in InAs/InGaAs/GaAs self-assembled quantum dots, embedded in a waveguide for laser applications, is measured using two independent methods: spectral hole burning and four-wave mixing. Without the application of bias current for electrical carrier injection......, a dephasing time of ~260 fs, weakly dependent on the optical excitation density, is found and attributed to phonon interaction. The application of bias current, leading to population inversion in the dot ground state and optical gain, strongly decreases the dephasing time to less than 50 fs, likely due...

  8. Control of interaction-induced dephasing of Bloch oscillations.

    Science.gov (United States)

    Gustavsson, M; Haller, E; Mark, M J; Danzl, J G; Rojas-Kopeinig, G; Nägerl, H-C

    2008-02-29

    We report on the control of interaction-induced dephasing of Bloch oscillations for an atomic Bose-Einstein condensate in an optical lattice. We quantify the dephasing in terms of the width of the quasimomentum distribution and measure its dependence on time for different interaction strengths which we control by means of a Feshbach resonance. For minimal interaction, the dephasing time is increased from a few to more than 20 thousand Bloch oscillation periods, allowing us to realize a BEC-based atom interferometer in the noninteracting limit.

  9. Neutral particle energy analyser based on time of flight technique for EXTRAP-T2R

    Energy Technology Data Exchange (ETDEWEB)

    Cecconello, M. [Royal Inst. of Tech., Stockholm (Sweden). Div. of Fusion Plasma Physics; Costa, S.; Murari, A.; Barzon, A. [Consorzio RFX, Padova (Italy)

    2001-07-01

    An important and not well-understood problem in the Reversed Field Pinch configuration is the anomalous ion heating. In all Ohmically heated RFPs, the ion temperature has been experimentally observed to be higher than can be accounted for by equilibration of energy from an Ohmically heated electron population. The mechanism driving the ions to such high energies is still debated. Different possible explanations have been investigated: kinetic Alfven waves turbulence, MHD relaxation processes and the excitation of an ion electrostatic wave by supra-thermal electrons. The measurement of the ion temperature is important in order to evaluate confinement. Furthermore, measurements can provide information on the mechanism behind the anomalous ion heating. The ion temperature is calculated from the neutral particles energy spectrum obtained by a neutral particles energy analyser based on the time of flight specifically developed for EXTRAP - T2R and here described in detail.

  10. Coherence and dephasing in self-assembled quantum dots

    DEFF Research Database (Denmark)

    Hvam, Jørn Märcher; Leosson, K.; Birkedal, Dan

    2003-01-01

    We measured dephasing times in InGaAl/As self-assembled quantum dots at low temperature using degenerate four-wave mixing. At 0K, the coherence time of the quantum dots is lifetime limited, whereas at finite temperatures pure dephasing by exciton-phonon interactions governs the quantum dot...... coherence. The inferred homogeneous line widths are significantly smaller than the line widths usually observed in the photoluminescence from single quantum dots indicating an additional inhomogeneours broadening mechanism in the latter....

  11. Fast mapping of the T2 relaxation time of cerebral metabolites using proton echo-planar spectroscopic imaging (PEPSI).

    Science.gov (United States)

    Tsai, Shang-Yueh; Posse, Stefan; Lin, Yi-Ru; Ko, Cheng-Wen; Otazo, Ricardo; Chung, Hsiao-Wen; Lin, Fa-Hsuan

    2007-05-01

    Metabolite T2 is necessary for accurate quantification of the absolute concentration of metabolites using long-echo-time (TE) acquisition schemes. However, lengthy data acquisition times pose a major challenge to mapping metabolite T2. In this study we used proton echo-planar spectroscopic imaging (PEPSI) at 3T to obtain fast T2 maps of three major cerebral metabolites: N-acetyl-aspartate (NAA), creatine (Cre), and choline (Cho). We showed that PEPSI spectra matched T2 values obtained using single-voxel spectroscopy (SVS). Data acquisition for 2D metabolite maps with a voxel volume of 0.95 ml (32 x 32 image matrix) can be completed in 25 min using five TEs and eight averages. A sufficient spectral signal-to-noise ratio (SNR) for T2 estimation was validated by high Pearson's correlation coefficients between logarithmic MR signals and TEs (R2 = 0.98, 0.97, and 0.95 for NAA, Cre, and Cho, respectively). In agreement with previous studies, we found that the T2 values of NAA, but not Cre and Cho, were significantly different between gray matter (GM) and white matter (WM; P PEPSI and SVS scans was less than 9%. Consistent spatial distributions of T2 were found in six healthy subjects, and disagreement among subjects was less than 10%. In summary, the PEPSI technique is a robust method to obtain fast mapping of metabolite T2.

  12. Determination of blood circulation times of superparamagnetic iron oxide nanoparticles by T2* relaxometry using ultrashort echo time (UTE) MRI.

    Science.gov (United States)

    Scharlach, Constantin; Warmuth, Carsten; Schellenberger, Eyk

    2015-11-01

    Blood circulation is an important determinant of the biodistribution of superparamagnetic iron oxide nanoparticles. Here we present a magnetic resonance imaging (MRI) technique based on the use of ultrafast echo times (UTE) for the noninvasive determination of blood half-lives at high particle concentrations, when conventional pulse sequences fail to produce a useful MR signal. Four differently coated iron oxide nanoparticles were administered intravenously at a dose of 500 μmol Fe/kg bodyweight and UTE images of C57BL/6 mice were acquired on a 1-T ICON scanner (Bruker). T2* relaxometry was done by acquiring UTE images with echo times of 0.1, 0.8 and 1.6 ms. Blood circulation time was then determined by fitting an exponential curve to the time course of the measured relaxation rates. Circulation time was shortest for particles coated with malic acid (t1/2=23 min) and longest for particles coated with tartaric acid (t1/2=63 min). UTE-based T2* relaxometry allows noninvasive determination of blood circulation time and is especially useful when high particle concentrations are present. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Evaluation of dysthyroid optic neuropathy using T2-relaxation time of extraocular muscle as parameter

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Fumihiko; Maeda, Toshine; Inoue, Toyoko; Inoue, Yoichi [Olympia Eye Hospital, Tokyo (Japan)

    2001-11-01

    The T2 value of magnetic resonance imaging (MRI) is useful in evaluating the activity of dysthyroid ophthlamopathy. We applied this method in evaluating dysthyroid optic neuropathy in 15 affected eyes of 15 patients. Another group of 40 eyes of 20 patients of dysthyroid opthalmopathy without hypertrophy of extraocular muscles served as control. The T2 value in dysthyroid optic neuropathy significantly decreased following treatment with corticosteroid but the value was still higher than that in control eyes. The findings show that the T2 value of MRI is useful in evaluating the therapeutic effect of dysthyroid optic neuropathy. (author)

  14. Radiatively Limited Dephasing and Exciton Dynamics in MoSe2 Monolayers Revealed with Four-Wave Mixing Microscopy.

    Science.gov (United States)

    Jakubczyk, Tomasz; Delmonte, Valentin; Koperski, Maciej; Nogajewski, Karol; Faugeras, Clément; Langbein, Wolfgang; Potemski, Marek; Kasprzak, Jacek

    2016-09-14

    By implementing four-wave mixing (FWM) microspectroscopy, we measure coherence and population dynamics of the exciton transitions in monolayers of MoSe2. We reveal their dephasing times T2 and radiative lifetime T1 in a subpicosecond (ps) range, approaching T2 = 2T1 and thus indicating radiatively limited dephasing at a temperature of 6 K. We elucidate the dephasing mechanisms by varying the temperature and by probing various locations on the flake exhibiting a different local disorder. At the nanosecond range, we observe the residual FWM produced by the incoherent excitons, which initially disperse toward the dark states but then relax back to the optically active states within the light cone. By introducing polarization-resolved excitation, we infer intervalley exciton dynamics, revealing an initial polarization degree of around 30%, constant during the initial subpicosecond decay, followed by the depolarization on a picosecond time scale. The FWM hyperspectral imaging reveals the doped and undoped areas of the sample, allowing us to investigate the neutral exciton, the charged one, or both transitions at the same time. In the latter, we observe the exciton-trion beating in the coherence evolution indicating their coherent coupling.

  15. Models of decoherence with negative dephasing rate

    CERN Document Server

    Pernice, Ansgar; Strunz, Walter T

    2012-01-01

    We determine the total state dynamics of a dephasing open quantum system using the standard environment of harmonic oscillators. Of particular interest are random unitary approaches to the same reduced dynamics and system-environment correlations in the full model. Concentrating on a model with an at times negative dephasing rate, the issue of "non-Markovianity" will also be addressed with the emphasis on information obtained from the dynamics of the total state of system and environment: making use of criteria that allow us to distinguish between classically correlated and entangled total states, we employ a simple measure for the correlations emerging from the increase of the two local entropies, and relate it the nature of the correlations.

  16. A direct comparison between two independently calibrated time transfer techniques: T2L2 and GPS Common-Views

    Science.gov (United States)

    Rovera, G. D.; Abgrall, M.; Courde, C.; Exertier, P.; Fridelance, P.; Guillemot, Ph; Laas-Bourez, M.; Martin, N.; Samain, E.; Sherwood, R.; Torre, J.-M.; Uhrich, P.

    2016-06-01

    We present a direct comparison between two satellite time transfer techniques on independently calibrated links: Time Transfer by Laser Link (T2L2) and Common-Views (CV) of satellites from the Global Positioning System (GPS) constellation. The GPS CV and T2L2 links between three European laboratories where independently calibrated against the same reference point of the local timescales. For all the links the mean values of the differences between GPS CV and T2L2 are equal or below 240 ps, with standard deviations below 500 ps, mostly due to GPS CV. Almost all deviations from 0 ns are within the combined uncertainty estimates. Despite the weak number of common points obtained, due to the fact that T2L2 is weather dependent, these results are providing an unprecedented sub-ns consistency between two independently calibrated microwave and optical satellite time transfer techniques.

  17. Usefulness of Postcontrast T2-Weighted Images in Shortening the Total Scan Time of a Gadoxectic Acid Enhanced MRI of the Liver: a Comparison between Precontrast and Postcontrast T2-Weighted Images

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Tae Kyung; Lee, Chang Hee; Lee, Jong Mee; Choi, Jae Woong; Kim, Kyeong Ah; Park, Cheol Min [Korea University Guro Hospital, Seoul (Korea, Republic of)

    2010-03-15

    We evaluated the effects of gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) on the overall image quality and lesion contrast of T2-weighted images (T2WI). We reviewed T2WI before and after Gd-EOB-DTPA enhancement in 50 patients with 41 focal liver lesions. Pre- and post-contrast T2WI were analyzed qualitatively and quantitatively. For the qualitative analysis, two abdominal radiologists, blinded to other findings in the study, retrospectively scored the image quality, lesion conspicuity, and artifacts. The quantitative analysis involved the measurement of the liver signal-to-noise ratio (SNR) and the lesion-to-liver contrast-to-noise ratio (CNR). Image quality and lesion conspicuity were not significantly different among the respiratory-triggered T2-weighted turbo spin-echo sequence (T2TSE), Half-fourier acquisition single-shot turbo spin-echo (HASTE) sequence, and breath-hold T2*- weighted gradient recalled-echo (GRE) sequences. However, there was a trend toward improved lesion conspicuity in post-contrast T2TSE. The quantitative analysis indicated that the SNR for post-contrast images was significantly higher than for pre-contrast images on T2TSE (p=0.04). No significant differences were seen in the CNR of focal lesions, but there was a trend towards an increase in the CNR for postcontrast T2WI of hepatocellular carcinoma. Compared to pre-contrast T2WI, post-contrast T2WI showed no handicap in the overall image quality and lesion contrast. Therefore, to shorten the total scan time during Gd-EOB-DTPA enhanced MRI, pre-contrast T2WI can be replaced by post-contrast T2WI.

  18. Sub-ns time transfer consistency: a direct comparison between GPS CV and T2L2

    Science.gov (United States)

    Exertier, P.; Samain, E.; Courde, C.; Aimar, M.; Torre, J. M.; Rovera, G. D.; Abgrall, M.; Uhrich, P.; Sherwood, R.; Herold, G.; Schreiber, U.; Guillemot, P.

    2016-12-01

    This paper presents a direct comparison between two satellite time transfer techniques: common-view (CV) of satellites from the global positioning system (GPS) constellation, and time transfer by laser link (T2L2) through the low orbiting satellite Jason-2. We describe briefly both techniques, together with two independent relative calibration campaigns of the links involving four European laboratories. Between the same remote time scale reference points, the mean values of the calibrated differences between GPS CV and T2L2 are below 240 ps, with standard deviations below 500 ps, mostly due to GPS CV. Almost all sample deviations from 0 ns are within the combined uncertainty estimates. Despite the relatively small number of common points obtained, due to the fact that T2L2 is weather dependent, these results provide an unprecedented sub-ns consistency between two independently calibrated microwave and optical satellite time transfer techniques.

  19. Gelfand-Dickey Algebra and Higher Spin Symmetries On $T^2=S^1\\times S^1$

    CERN Document Server

    Sedra, M B

    2007-01-01

    We focus in this work to renew the interest in higher conformal spins symmetries and their relations to quantum field theories and integrable models. We consider the extension of the conformal Frappat et al. symmetries containing the Virasoro and the Antoniadis et al. algebras as particular cases describing geometrically special diffeomorphisms of the two dimensional torus $T^2$. We show in a consistent way, and explicitly, how one can extract these generalized symmetries from the Gelfand-Dickey algebra. The link with Liouville and Toda conformal field theories is established and various important properties are discussed.

  20. Knee Cartilage Thickness, T1ρ and T2 Relaxation Time Are Related to Articular Cartilage Loading in Healthy Adults

    Science.gov (United States)

    Van Rossom, Sam; Smith, Colin Robert; Zevenbergen, Lianne; Thelen, Darryl Gerard; Vanwanseele, Benedicte; Van Assche, Dieter; Jonkers, Ilse

    2017-01-01

    Cartilage is responsive to the loading imposed during cyclic routine activities. However, the local relation between cartilage in terms of thickness distribution and biochemical composition and the local contact pressure during walking has not been established. The objective of this study was to evaluate the relation between cartilage thickness, proteoglycan and collagen concentration in the knee joint and knee loading in terms of contact forces and pressure during walking. 3D gait analysis and MRI (3D-FSE, T1ρ relaxation time and T2 relaxation time sequence) of fifteen healthy subjects were acquired. Experimental gait data was processed using musculoskeletal modeling to calculate the contact forces, impulses and pressure distribution in the tibiofemoral joint. Correlates to local cartilage thickness and mean T1ρ and T2 relaxation times of the weight-bearing area of the femoral condyles were examined. Local thickness was significantly correlated with local pressure: medial thickness was correlated with medial condyle contact pressure and contact force, and lateral condyle thickness was correlated with lateral condyle contact pressure and contact force during stance. Furthermore, average T1ρ and T2 relaxation time correlated significantly with the peak contact forces and impulses. Increased T1ρ relaxation time correlated with increased shear loading, decreased T1ρ and T2 relaxation time correlated with increased compressive forces and pressures. Thicker cartilage was correlated with higher condylar loading during walking, suggesting that cartilage thickness is increased in those areas experiencing higher loading during a cyclic activity such as gait. Furthermore, the proteoglycan and collagen concentration and orientation derived from T1ρ and T2 relaxation measures were related to loading. PMID:28076431

  1. Dephasing and interaction of excitons CdSe/ZnSe islands

    DEFF Research Database (Denmark)

    Wagner, H. P.; Tranitz, H.-P.; Preis, H.;

    2000-01-01

    The dephasing of excitons in self-organized CdSe/ZnSe islands grown by molecular-beam epitaxy is investigated using spectrally resolved four-wave mixing. A distribution of dephasing times is observed, indicating the existence of localized excitons with different relaxation times at comparable...

  2. Dephasing and interaction of excitons CdSe/ZnSe islands

    DEFF Research Database (Denmark)

    Wagner, H. P.; Tranitz, H.-P.; Preis, H.

    2000-01-01

    The dephasing of excitons in self-organized CdSe/ZnSe islands grown by molecular-beam epitaxy is investigated using spectrally resolved four-wave mixing. A distribution of dephasing times is observed, indicating the existence of localized excitons with different relaxation times at comparable...

  3. Phonon induced pure dephasing process of excitonic state in colloidal semiconductor quantum dots

    Science.gov (United States)

    Huang, Tongyun; Han, Peng; Wang, Xinke; Feng, Shengfei; Sun, Wenfeng; Ye, Jiasheng; Zhang, Yan

    2016-04-01

    We present a theoretical study on the pure dephasing process of colloidal semiconductor quantum dots induced by lattice vibrations using continuum model calculations. By solving the time dependent Liouville-von Neumann equation, we present the ultrafast Rabi oscillations between excitonic state and virtual state via exciton-phonon interaction and obtain the pure dephasing time from the fast decayed envelope of the Rabi oscillations. The interaction between exciton and longitudinal optical phonon vibration is found to dominate the pure dephasing process and the dephasing time increases nonlinearly with the reduction of exciton-phonon coupling strength. We further find that the pure dephasing time of large quantum dots is more sensitive to temperature than small quantum dots.

  4. Knee muscle strength correlates with joint cartilage T2 relaxation time in young participants with risk factors for osteoarthritis.

    Science.gov (United States)

    Macías-Hernández, Salvador Israel; Miranda-Duarte, Antonio; Ramírez-Mora, Isabel; Cortés-González, Socorro; Morones-Alba, Juan Daniel; Olascoaga-Gómez, Andrea; Coronado-Zarco, Roberto; Soria-Bastida, María de Los Angeles; Nava-Bringas, Tania Inés; Cruz-Medina, Eva

    2016-08-01

    The objective of this study is to correlate T2 relaxation time (T2RT), measured by magnetic resonance imaging (MRI) with quadriceps and hamstring strength in young participants with risk factors for knee osteoarthritis (OA). A descriptive cross-sectional study was conducted with participants between 20 and 40 years of age, without diagnosis of knee OA. Their T2 relaxation time was measured through MRI, and their muscle strength (MS) was measured with an isokinetic dynamometer. Seventy-one participants were recruited, with an average age of 28.3 ± 5.5 years; 39 (55 %) were females. Negative correlations were found between T2RT and quadriceps peak torque (QPT) in males in the femur r = -0.46 (p = 0.01), tibia r = -0.49 (p = 0.02), and patella r = -0.44 (p = 0.01). In women, correlations were found among the femur r = -0.43 (p = 0.01), tibia r = -0.61 (p = 0.01), and patella r = -0.32 (p = 0.05) and among hamstring peak torque (HPT), in the femur r = -0.46 (p = 0.01), hamstring total work (HTW) r = -0.42 (p = 0.03), and tibia r = -0.33 (p = 0.04). Linear regression models showed good capacity to predict T2RT through QPT in both genders. The present study shows that early changes in femoral, tibial, and patellar cartilage are significantly correlated with MS, mainly QPT, and that these early changes might be explained by MS, which could play an important role in pre-clinical phases of the disease.

  5. Exciton dephasing and biexciton binding in CdSe/ZnSe islands

    DEFF Research Database (Denmark)

    Wagner, Hans Peter; Tranitz, H.-P.; Preis, H;

    1999-01-01

    The dephasing of excitons and the formation of biexcitons in self-organized CdSe/ZnSe islands grown by molecular-beam epitaxy is investigated using spectrally resolved four-wave mixing. A distribution of exciton-exciton scattering efficiencies and dephasing times in the range of 0.5-10 ps...

  6. Nonlinear Response of Localized Excitons: Effects of the Excitation-Induced Dephasing

    DEFF Research Database (Denmark)

    Borri, Paola; Langbein, Wolfgang Werner; Birkedal, Dan;

    1997-01-01

    . In particular, we show experimentally that the excitation-induced dephasing gives rise to a photon echo in inhomogeneous systems. We develop a simple analytical model for the delay dependence of the signal, which enables us to deduce the dephasing time from the four-wave mixing decay....

  7. Effect of dephasing on DNA sequencing via transverse electronic transport

    Energy Technology Data Exchange (ETDEWEB)

    Zwolak, Michael [Los Alamos National Laboratory; Krems, Matt [NON LANL; Pershin, Yuriy V [NON LANL; Di Ventra, Massimiliano [NON LANL

    2009-01-01

    We study theoretically the effects of dephasing on DNA sequencing in a nanopore via transverse electronic transport. To do this, we couple classical molecular dynamics simulations with transport calculations using scattering theory. Previous studies, which did not include dephasing, have shown that by measuring the transverse current of a particular base multiple times, one can get distributions of currents for each base that are distinguishable. We introduce a dephasing parameter into transport calculations to simulate the effects of the ions and other fluctuations. These effects lower the overall magnitude of the current, but have little effect on the current distributions themselves. The results of this work further implicate that distinguishing DNA bases via transverse electronic transport has potential as a sequencing tool.

  8. Linde problem in Yang-Mills theory compactified on $\\mathbb{R}^2 \\times \\mathbb{T}^2$

    CERN Document Server

    Fraga, Eduardo S; Noronha, Jorge

    2016-01-01

    We investigate the perturbative expansion in $SU(3)$ Yang-Mills theory compactified on $\\mathbb{R}^2\\times \\mathbb{T}^2$ where the compact space is a torus $\\mathbb{T}^2= S^1_{\\beta}\\times S^1_{L}$, with $S^1_{\\beta}$ being a thermal circle with period $\\beta=1/T$ ($T$ is the temperature) while $S^1_L$ is a circle with length $L=1/\\Lambda$ where $\\Lambda$ is an energy scale. A Linde-type analysis indicates that perturbative calculations for the pressure in this theory break down already at order $\\mathcal{O}(g^2)$ due to the presence of a non-perturbative scale $\\sim g \\sqrt{T\\Lambda}$. We conjecture that a similar result should hold if the torus is replaced by any compact surface of genus one.

  9. Pure dephasing of single Mn spin in semiconductor quantum dots

    Science.gov (United States)

    Liu, Dingyang; Lai, Wenxi; Yang, Wen

    2017-08-01

    We present comprehensive analytical and numerical studies on the pure dephasing of a single Mn spin in a semiconductor quantum dot due to (i) its sp-d exchange interaction with an electronic environment, and (ii) its hyperfine interaction with the nuclear spin environment. For (i), by modeling the electronic environment by an open two-level system, we provide exact analytical expressions and present detailed analysis for the Mn spin pure dephasing in both the Markovian and non-Markovian regimes. This provides a clear physical picture and a general theoretical framework based on which we estimate the Mn spin pure dephasing due to various fluctuations (such as thermal excitation, optical pumping, tunneling, or electron/hole spin relaxation) of the electronic environment and reveals a series of interesting behaviors, such as thermal, optical, and electrical control of the crossover between the Markov and non-Markov regimes. In particular, we find rapid Mn spin pure dephasing on a nanosecond time scale by the thermal fluctuation and optical pumping, but these mechanisms can be strongly suppressed by shifting the electron envelope function relative to the Mn atom with an external electric field through the quantum-confined Stark effect. The thermal fluctuation mechanism is also exponentially suppressed at low temperature. For (ii), we find that the Mn spin dephasing time is limited by the thermal fluctuation of the nuclear spins to a few microseconds even at low temperature and its value varies from sample to sample, depending on the distribution of spinful isotopes on the nearest-neighbor sites surrounding the substitutional Mn atom. Our findings may be useful to understand and suppress the Mn spin pure dephasing for its applications in quantum information processing.

  10. Physical Activity and Spatial Differences in Medial Knee T1rho and T2 Relaxation Times in Knee Osteoarthritis

    Science.gov (United States)

    KUMAR, DEEPAK; SOUZA, RICHARD B.; SINGH, JUSTIN; CALIXTO, NATHANIEL E.; NARDO, LORENZO; LINK, THOMAS M.; LI, XIAOJUAN; MAJUMDAR, SHARMILA

    2015-01-01

    STUDY DESIGN Cross-sectional. OBJECTIVES To investigate the association between knee loading–related osteoarthritis (OA) risk factors (obesity, malalignment, and physical activity) and medial knee laminar (superficial and deep) T1rho and T2 relaxation times. BACKGROUND The interaction of various modifiable loading-related knee risk factors and cartilage health in knee OA is currently not well known. METHODS Participants with and without knee OA (n = 151) underwent magnetic resonance imaging at 3 T for superficial and deep cartilage T1rho and T2 magnetic resonance relaxation times in the medial femur (MF) and medial tibia (MT). Other variables included radiographic Kellgren-Lawrence (KL) grade, alignment, pain and symptoms using the Knee injury and Osteoarthritis Outcome Score, and physical activity using the International Physical Activity Questionnaire (IPAQ). Individuals with a KL grade of 4 were excluded. Group differences were calculated using 1-way analysis of variance, adjusting for age and body mass index. Linear regression models were created with age, sex, body mass index, alignment, KL grade, and the IPAQ scores to predict the laminar T1rho and T2 times. RESULTS Total IPAQ scores were the only significant predictors among the loading-related variables for superficial MF T1rho (P = .005), deep MT T1rho (P = .026), and superficial MF T2 (P = .049). Additionally, the KL grade predicted the superficial MF T1rho (P = .023) and deep MT T1rho (P = .022). CONCLUSION Higher physical activity levels and worse radiographic severity of knee OA, but not obesity or alignment, were associated with worse cartilage composition. PMID:25353261

  11. Time-resolved VUV spectroscopy in the EXTRAP-T2 reversed field pinch

    Science.gov (United States)

    Hedqvist, Anders; Rachlew-Källne, Elisabeth

    1998-09-01

    Time-resolved VUV spectroscopy has been used to investigate the effects of impurities in a reversed field pinch operating with a resistive shell. Results of electron temperature, impurity ion densities, particle confinement time and 0741-3335/40/9/004/img1 together with a description of the interpretation and the equipment are presented.

  12. Exciton dephasing in ZnSe quantum wires

    DEFF Research Database (Denmark)

    Wagner, Hans Peter; Langbein, Wolfgang Werner; Hvam, Jørn Märcher

    1998-01-01

    The homogeneous linewidths of excitons in wet-etched ZnSe quantum wires of lateral sizes down to 23 nm are studied by transient four-wave mixing. The low-density dephasing time is found to increase with decreasing wire width. This is attributed mainly to a reduction of electron-exciton scattering...

  13. Robust and fragile Werner states in the collective dephasing Robust and fragile Werner states in the collective dephasing

    CERN Document Server

    Li, S B; Li, S B; Xu, J B; Li, Shang-Bin; Xu, Jing-Bo; Li, Shang-Bin; Xu, Jing-Bo

    2005-01-01

    We investigate the concurrence and Bell violation of the Werner or Werner-like states in the presence of collective dephasing. It is shown that the Werner and certain kinds of Werner-like states are robust against the collective dephasing, and some kinds of Werner-like states is fragile and becomes completely disentangled in a finite-time. The threshold time of complete disentanglement of the Werner state is given. The influence of external driving field on the finite-time disentanglement of Werner states is discussed. Finally, we present a simple method to control the stationary state entanglement of two qubits. We investigate the concurrence and Bell violation of the Werner or Werner-like states in the presence of collective dephasing. It is shown that the Werner and certain kinds of Werner-like states are robust against the collective dephasing, and some kinds of Werner-like states is fragile and becomes completely disentangled in a finite-time. The threshold time of complete disentanglement of the Werner ...

  14. Quantitative Assessment of the T2 Relaxation Time of the Gluteus Muscles in Children with Duchenne Muscular Dystrophy: a Comparative Study Before and After Steroid Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hee Kyung; Laor, Tal; Wong, Brenda [Cincinnati Children' s Hospital Medical Center, Cincinnati (United States); Horn, Paul S. [University of Cincinnati, Cincinnati (United States)

    2010-06-15

    To determine the feasibility of using T2 mapping as a quantitative method to longitudinally follow the disease activity in children with Duchenne muscular dystrophy (DMD) who are treated with steroids. Eleven boys with DMD (age range: 5-14 years) underwent evaluation with the clinical functional score (CFS), and conventional pelvic MRI and T2 mapping before and during steroid therapy. The gluteus muscle inflammation and fatty infiltration were evaluated on conventional MRI. The histograms and mean T2 relaxation times were obtained from the T2 maps. The CFS, the conventional MRI findings and the T2 values were compared before and during steroid therapy. None of the patients showed interval change of their CFSs. On conventional MRI, none of the images showed muscle inflammation. During steroid treatment, two boys showed increased fatty infiltration on conventional MRI, and both had an increase of the mean T2 relaxation time (p < 0.05). The remaining nine boys had no increase in fatty infiltration. Of these, three showed an increased mean T2 relaxation time (p < 0.05), two showed no change and four showed a decreased mean T2 relaxation time (p < 0.05). T2 mapping is a feasible technique to evaluate the longitudinal muscle changes in those children who receive steroid therapy for DMD. The differences of the mean T2 relaxation time may reflect alterations in disease activity, and even when the conventional MRI and CFS remain stable.

  15. Time Transfer by Laser Link - the T2L2 Experiment on JASON-2 and Further Experiments

    Science.gov (United States)

    Samain, Étienne; Weick, Jonathan; Vrancken, Patrick; Para, Franck; Albanese, Dominique; Paris, Jocelyn; Torre, Jean-Marie; Zhao, Cheng; Guillemot, Philippe; Petitbon, Isabelle

    The new generation of optical time transfer will allow the synchronization of remote ultra stable clocks and the determination of their performances over intercontinental distances. The principle of T2L2 (Time Transfer by Laser Link) is based on the techniques of satellite laser ranging coupled with time-frequency metrology. It consists of synchronizing ground and space clocks using short laser pulses travelling between ground clocks and satellite equipment. The instrument will be integrated on the ocean altimetry satellite Jason-2 that is scheduled for launch in 2008. The experiment should enhance the performance of time transfer by one or two magnitudes compared to existing microwave techniques such as GPS and Two-Way Satellite Time and Frequency Transfer (TWSTFT).

  16. Thermodynamics of a qubit undergoing dephasing

    Science.gov (United States)

    Marcantoni, S.

    2017-05-01

    The thermodynamics of a qubit undergoing dephasing due to the coupling with the external environment is discussed. First of all, we assume the dynamics of the system to be described by a master equation in Lindblad form. In this framework, we review a standard formulation of the first and second law of thermodynamics that has been known in literature for a long time. After that, we explicitly model the environment with a set of quantum harmonic oscillators choosing the interaction such that the global dynamics of system and bath is analytically solvable and the Lindblad master equation is recovered in the weak-coupling limit. In this generalized setting, we can show that the correlations between system and bath play a fundamental role in the heat exchange. Moreover, the internal entropy production of the qubit is proven to be positive for arbitrary coupling strength.

  17. Dephasing in self-organized InAlGaAs quantum dots

    DEFF Research Database (Denmark)

    Leosson, K.; Birkedal, Dan; Hvam, Jørn Märcher

    2002-01-01

    temperatures. We observe a striking discrepancy between the homogenous linewidth derived from the dephasing times and the measured photoluminescene linewidth of individual quantum dots, indicating the presence of an additional inhomogenous broadening mechanism in photoluminescence measurements of single......We report the first direct measurements of dephasing in III-V semiconductor quantum dots at low temperature using degenerate four-wave mixing. At OK, the coherence time is limited by the population lifetime whereas pure dephasing due to exciton-phonon interactions appears only at finite...... quantum dots....

  18. Effects of Electric and Magnetic Fields on Pure Dephasing of Exciton Qubits

    Institute of Scientific and Technical Information of China (English)

    LIU Yun-Fei; XIAO Jing-Lin

    2009-01-01

    In a two-dimensional quantum dot (QD) with parabolic confinement potential, we investigate pure dephasing due to deformation potential exciton-bulk longitudinal acoustic phonons (LAP) interaction for exciton qubits under the influence of external static electric and magnetic fields by adopting the full quantum-mechanical method of Kunihiro Kojima and Akihisa Tomita. The wave function is found and the dependence of the pure dephusing factor on the confinement length of the QD and time and temperature is discussed. We find the external electric and magnetic fields have important effects on pure dephasing of exciton qubits because exciton-LAP interaction increases, leading to more pure dephasing.

  19. Electron Spin Dephasing and Decoherence by Interaction with Nuclear Spins in Self-Assembled Quantum Dots

    Science.gov (United States)

    Lee, Seungwon; vonAllmen, Paul; Oyafuso, Fabiano; Klimeck, Gerhard; Whale, K. Birgitta

    2004-01-01

    Electron spin dephasing and decoherence by its interaction with nuclear spins in self-assembled quantum dots are investigated in the framework of the empirical tight-binding model. Electron spin dephasing in an ensemble of dots is induced by the inhomogeneous precession frequencies of the electron among dots, while electron spin decoherence in a single dot arises from the inhomogeneous precession frequencies of nuclear spins in the dot. For In(x)Ga(1-x) As self-assembled dots containing 30000 nuclei, the dephasing and decoherence times are predicted to be on the order of 100 ps and 1 (micro)s.

  20. Optical Bloch Equations Modified with Phonon-Induced Intensity-Dependent Dephasing

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    We extend the exciton population equations of a two-level quantum dot system with weak excitation to the ones with strong excitations, in which, the phonon-induced intensity-dependent dephasing time and decay rate are involved. The straightforward calculated populations from the modified population equations demonstrate the damping behavior of Rabi oscillation as the external field increasing. The effect of the intensity-dependent dephasing time and the intensity-dependent decay rate are also discussed.

  1. The application of T1 and T2 relaxation time and magnetization transfer ratios to the early diagnosis of patellar cartilage osteoarthritis

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Weiwu; Qu, Nan; Lu, Zhihua; Yang, Shixun [Shanghai Jiaotong University, Department of Radiology, Shanghai (China)

    2009-11-15

    We compare the T1 and T2 relaxation times and magnetization transfer ratios (MTRs) of normal subjects and patients with osteoarthritis (OA) to evaluate the ability of these techniques to aid in the early diagnosis and treatment of OA. The knee joints in 11 normal volunteers and 40 patients with OA were prospectively evaluated using T1 relaxation times as measured using delayed gadolinium-enhanced MRI of cartilage (dGEMRIC), T2 relaxation times (multiple spin-echo sequence, T2 mapping), and MTRs. The OA patients were further categorized into mild, moderate, and severe OA. The mean T1 relaxation times of the four groups (normal, mild OA, moderate OA, and severe OA) were: 487.3{+-}27.7, 458.0{+-}55.9, 405.9{+-}57.3, and 357.9{+-}36.7 respectively (p<0.001). The mean T2 relaxation times of the four groups were: 37.8{+-}3.3, 44.0{+-}8.5, 50.9{+-}9.5, and 57.4{+-}4.8 respectively (p<0.001). T1 relaxation time decreased and T2 relaxation time increased with worsening degeneration of patellar cartilage. The result of the covariance analysis showed that the covariate age had a significant influence on T2 relaxation time (p<0.001). No significant differences between the normal and OA groups using MTR were noted. T1 and T2 relaxation times are relatively sensitive to early degenerative changes in the patellar cartilage, whereas the MTR may have some limitations with regard to early detection of OA. In addition, The T1 and T2 relaxation times negatively correlate with each other, which is a novel finding. (orig.)

  2. Dyakonov-Perel Effect on Spin Dephasing in n-Type GaAs

    Science.gov (United States)

    Ning, C. Z.; Wu, M. W.

    2003-01-01

    A paper presents a study of the contribution of the Dyakonov-Perel (DP) effect to spin dephasing in electron-donor-doped bulk GaAs in the presence of an applied steady, moderate magnetic field perpendicular to the growth axis of the GaAs crystal. (The DP effect is an electron-wave-vector-dependent spin-state splitting of the conduction band, caused by a spin/orbit interaction in a crystal without an inversion center.) The applicable Bloch equations of kinetics were constructed to include terms accounting for longitudinal optical and acoustic phonon scattering as well as impurity scattering. The contributions of the aforementioned scattering mechanisms to spin-dephasing time in the presence of DP effect were examined by solving the equations numerically. Spin-dephasing time was obtained from the temporal evolution of the incoherently summed spin coherence. Effects of temperature, impurity level, magnetic field, and electron density on spin-dephasing time were investigated. Spin-dephasing time was found to increase with increasing magnetic field. Contrary to predictions of previous simplified treatments of the DP effect, spin-dephasing time was found to increase with temperature in the presence of impurity scattering. These results were found to agree qualitatively with results of recent experiments.

  3. Evaluation of articular cartilage in patients with femoroacetabular impingement (FAI) using T2* mapping at different time points at 3.0 Tesla MRI: a feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Apprich, S.; Mamisch, T.C. [University of Bern, Department of Orthopedic Surgery, Bern (Switzerland); Medical University of Vienna, Department of Radiology, MR Centre of Excellence, Vienna (Austria); Welsch, G.H. [Medical University of Vienna, Department of Radiology, MR Centre of Excellence, Vienna (Austria); University of Erlangen-Nuernberg, Department of Trauma Surgery, Erlangen (Germany); Bonel, H. [University of Bern, Department of Radiology, Bern (Switzerland); Siebenrock, K.A.; Dudda, M. [University of Bern, Department of Orthopedic Surgery, Bern (Switzerland); Kim, Y.J. [Harvard Medical School, Department of Orthopaedic Surgery, Children' s Hospital, Boston, MA (United States); Trattnig, S. [Medical University of Vienna, Department of Radiology, MR Centre of Excellence, Vienna (Austria)

    2012-08-15

    To define the feasibility of utilizing T2* mapping for assessment of early cartilage degeneration prior to surgery in patients with symptomatic femoroacetabular impingement (FAI), we compared cartilage of the hip joint in patients with FAI and healthy volunteers using T2* mapping at 3.0 Tesla over time. Twenty-two patients (13 females and 9 males; mean age 28.1 years) with clinical signs of FAI and Toennis grade {<=} 1 on anterior-posterior x-ray and 35 healthy age-matched volunteers were examined at a 3 T MRI using a flexible body coil. T2* maps were calculated from sagittal- and coronal-oriented gradient-multi-echo sequences using six echoes (TR 125, TE 4.41/8.49/12.57/16.65/20.73/24.81, scan time 4.02 min), both measured at beginning and end of the scan (45 min time span between measurements). Region of interest analysis was manually performed on four consecutive slices for superior and anterior cartilage. Mean T2* values were compared among patients and volunteers, as well as over time using analysis of variance and Student's t-test. Whereas quantitative T2* values for the first measurement did not reveal significant differences between patients and volunteers, either for sagittal (p = 0.644) or coronal images (p = 0.987), at the first measurement, a highly significant difference (p {<=} 0.004) was found for both measurements with time after unloading of the joint. Over time we found decreasing mean T2* values for patients, in contrast to increasing mean T2* relaxation times in volunteers. The study proved the feasibility of utilizing T2* mapping for assessment of early cartilage degeneration in the hip joint in FAI patients at 3 Tesla to predict possible success of joint-preserving surgery. However, we suggest the time point for measuring T2* as an MR biomarker for cartilage and the changes in T2* over time to be of crucial importance for designing an MR protocol in patients with FAI. (orig.)

  4. Combined quantification of fatty infiltration, T 1-relaxation times and T 2*-relaxation times in normal-appearing skeletal muscle of controls and dystrophic patients.

    Science.gov (United States)

    Leporq, Benjamin; Le Troter, Arnaud; Le Fur, Yann; Salort-Campana, Emmanuelle; Guye, Maxime; Beuf, Olivier; Attarian, Shahram; Bendahan, David

    2017-08-01

    To evaluate the combination of a fat-water separation method with an automated segmentation algorithm to quantify the intermuscular fatty-infiltrated fraction, the relaxation times, and the microscopic fatty infiltration in the normal-appearing muscle. MR acquisitions were performed at 1.5T in seven patients with facio-scapulo-humeral dystrophy and eight controls. Disease severity was assessed using commonly used scales for the upper and lower limbs. The fat-water separation method provided proton density fat fraction (PDFF) and relaxation times maps (T 2* and T 1). The segmentation algorithm distinguished adipose tissue and normal-appearing muscle from the T 2* map and combined active contours, a clustering analysis, and a morphological closing process to calculate the index of fatty infiltration (IFI) in the muscle compartment defined as the relative amount of pixels with the ratio between the number of pixels within IMAT and the total number of pixels (IMAT + normal appearing muscle). In patients, relaxation times were longer and a larger fatty infiltration has been quantified in the normal-appearing muscle. T 2* and PDFF distributions were broader. The relaxation times were correlated to the Vignos scale whereas the microscopic fatty infiltration was linked to the Medwin-Gardner-Walton scale. The IFI was linked to a composite clinical severity scale gathering the whole set of scales. The MRI indices quantified within the normal-appearing muscle could be considered as potential biomarkers of dystrophies and quantitatively illustrate tissue alterations such as inflammation and fatty infiltration.

  5. Dephasing-assisted selective incoherent quantum transport.

    Science.gov (United States)

    Behzadi, Naghi; Ahansaz, Bahram; Kasani, Hadi

    2015-10-01

    Selective energy transport throughout a quantum network connected to more than one reaction center can play an important role in many natural and technological considerations in photosystems. In this work, we propose a method in which an excitation can be transported from the original site of the network to one of the reaction centers arbitrarily using independent sources of dephasing noises. We demonstrate that in the absence of dephasing noises, the coherent evolution of the system does not have any role in energy transport in the network. Therefore, incoherent evolution via application of dephasing noises throughout a selected path of the network leads to complete transferring of the excitation to a desired reaction center.

  6. Geometry of quantum transport for dephasing Lindbladians

    CERN Document Server

    Avron, J E; Graf, G M; Kenneth, O

    2010-01-01

    We develop a geometric theory of adiabatic transport in driven open systems governed by dephasing Lindbladians. The coefficients of dissipative transport are determined by the Fubini-Study metric and the coefficients of non-dissipative transport by the adiabatic curvature. This gives a possible mechanism for residual resistance for gapped systems at low temperatures. When the metric and symplectic form are compatible non-dissipative terms in the inverse matrix of transport coefficients are immune to dephasing. We give three examples of compatible systems: The qubit, coherent states for the Harmonic oscillator and the lowest Landau level on a torus.

  7. Dephasing of quantum tunnelling in molecular nanomagnets

    Institute of Scientific and Technical Information of China (English)

    Zhang Shu-Qun; Chen Zhi-De

    2008-01-01

    Dephasing mechanism of quantum tunnelling in molecular magnets has been studied by means of the spin-coherentstate path integral in a mean field approximation. It is found that the fluctuating uncompensated transverse field from the dipolar-dipolar interaction between molecular magnets contributes a random phase to the quantum interference phase. The resulting transition rate is determined by the average tunnel splitting over the random phase. Such a dephasing process leads to the suppression of quenching due to the quantum phase interference, and to the steps due to odd resonances in hysteresis loop survived, which is in good agreement with experimental observations in molecular nanomagnets Fee and Mn12.

  8. Ultrafast dephasing of interband transitions in semiconductors

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Haichao

    2001-01-01

    [1]Becker, P. C., Fragnito, H. L., Brito, C. C. H. et al., Femtosecond photon echoes from band-to-band transitions in GaAs, Phys. Rev. Lett., 1988, 61: 1647—1649.[2]Lin, W. Z., Schoenlein, R. W., Fujimoto, J. G. et al., Femtosecond absorption saturation of hot carriers in GaAs and AlGaAs, IEEE JQE, 1988, 24: 267—275.[3]Gurevich, V. L., Muradov, M. I., Parshin, D. A., On the theory of femtosecond photon echoes from band-to -band transitions in semiconductors, Europhys. Lett., 1990, 12(4): 375—379.[4]Sayed, K. E., Bányai, L., Haug, H., Coulomb quantum kinetics and optical dephasing on the femtosecond time scale, Phys. Rev. B, 1994, 50:1541—1550.[5]Arlt, S., Siegner, U., Kunde, J. et al., Ultrafast dephasing of continuum transitions in bulk semiconductors, Phys. Rev. B, 1999, 59: 14860—14863.[6]Hügel, W. A., Heinrich, M. F., Wegener, M. et al., Photon echoes from semiconductor band-to -band continuum transitions in the regime of Coulomb quantum kinetics, Phys. Rev. Lett., 1999, 83(16): 3313—3316.[7]Scott, D. C., Binder, R., Koch, S. W., Ultrafast dephasing through acoustic plasmon undamping in nonequilibrium electron-hole plasmas, Phys. Rev. Lett., 1992, 69(2): 347—350.[8]Binder, R., Scott, D., Paul, A. E. et al., Carrier-carrier scattering and optical dephasing in highly excited semiconductors, Phys. Rev., B 1991, 45: 1107—1114.[9]Schilp, J., Kuhn, T., Mahler, G., Electron-phonon quantum kinetics in pulse-excited semiconductors: Memory and renormalization effects, Phys. Rev. B, 1994, 50: 5435—5447.[10]Snoke, D. W., Density dependence of electron scattering at low density, Phys. Rev., B 1994, 50: 11583—11591.[11]Leitenstorfer, A., Lohner, A., Rick, K. et al., Excitonic and free-carrier polarizations of bulk GaAs studied by femtosecond coherent spectroscopy, Phys. Rev., 1994B 49: 16372—16380.[12]Zhang, H. C., Wen, J. H., Guo, B. Hole-hole scattering of photoexcited heavy-holes in GaAs, Acta Physica

  9. Prolonged spontaneous emission and dephasing of localized excitons in air-bridged carbon nanotubes

    Science.gov (United States)

    Sarpkaya, Ibrahim; Zhang, Zhengyi; Walden-Newman, William; Wang, Xuesi; Hone, James; Wong, Chee W.; Strauf, Stefan

    2013-07-01

    The bright exciton emission of carbon nanotubes is appealing for optoelectronic devices and fundamental studies of light-matter interaction in one-dimensional nanostructures. However, to date, the photophysics of excitons in carbon nanotubes is largely affected by extrinsic effects. Here we perform time-resolved photoluminescence measurements over 14 orders of magnitude for ultra-clean carbon nanotubes bridging an air gap over pillar posts. Our measurements demonstrate a new regime of intrinsic exciton photophysics with prolonged spontaneous emission times up to T1=18 ns, about two orders of magnitude better than prior measurements and in agreement with values hypothesized by theorists about a decade ago. Furthermore, we establish for the first time exciton decoherence times of individual nanotubes in the time domain and find fourfold prolonged values up to T2=2.1 ps compared with ensemble measurements. These first observations motivate new discussions about the magnitude of the intrinsic dephasing mechanism while the prolonged exciton dynamics is promising for applications.

  10. A very simple, robust and fast method for estimating and displaying average time constants of T2 decays from multiecho MRI images using color intensity projections

    CERN Document Server

    Cover, Keith S

    2008-01-01

    While the multiexponential nature of T2 decays measured in vivo is well known, characterizing T2 decays by a single time constant is still very useful when differentiating among structures and pathologies in MRI images. A novel, robust, fast and very simple method is presented for both estimating and displaying the average time constant for the T2 decay of each pixel from a multiecho MRI sequence. The average time constant is calculated from the average of the values measured from the T2 decay over many echoes. For a monoexponential decay, the normalized decay average varies monotonically with the time constant. Therefore, it is simple to map any normalized decay average to an average time constant. This method takes advantage of the robustness of the normalized decay average to both artifacts and multiexponential decays. Color intensity projections (CIPs) were used to display 32 echoes acquired at a 10ms spacing as a single color image. The brightness of each pixel in each color image was determined by the i...

  11. Determination of intra-axial brain tumors cellularity through the analysis of T2 Relaxation time of brain tumors before surgery using MATLAB software.

    Science.gov (United States)

    Abdolmohammadi, Jamil; Shafiee, Mohsen; Faeghi, Fariborz; Arefan, Douman; Zali, Alireza; Motiei-Langroudi, Rouzbeh; Farshidfar, Zahra; Nazarlou, Ali Kiani; Tavakkoli, Ali; Yarham, Mohammad

    2016-08-01

    Timely diagnosis of brain tumors could considerably affect the process of patient treatment. To do so, para-clinical methods, particularly MRI, cannot be ignored. MRI has so far answered significant questions regarding tumor characteristics, as well as helping neurosurgeons. In order to detect the tumor cellularity, neuro-surgeons currently have to sample specimens by biopsy and then send them to the pathology unit. The aim of this study is to determine the tumor cellularity in the brain. In this cross-sectional study, 32 patients (18 males and 14 females from 18-77 y/o) were admitted to the neurosurgery department of Shohada-E Tajrish Hospital in Tehran, Iran from April 2012 to February 2014. In addition to routine pulse sequences, T2W Multi echo pulse sequences were taken and the images were analyzed using the MATLAB software to determine the brain tumor cellularity, compared with the biopsy. These findings illustrate the need for more T2 relaxation time decreases, the higher classes of tumors will stand out in the designed table. In this study, the results show T2 relaxation time with a 85% diagnostic weight, compared with the biopsy, to determine the brain tumor cellularity (p<0.05). Our results indicate that the T2 relaxation time feature is the best method to distinguish and present the degree of intra-axial brain tumors cellularity (85% accuracy compared to biopsy). The use of more data is recommended in order to increase the percent accuracy of this techniques.

  12. T2K & beyond

    CERN Document Server

    Catanesi, M G

    2016-01-01

    This article presents the status of the art of the T2K experiment and the measurements prospects for the incoming years. After a brief description of the experiment, the most recent results will be illustrated. The observation of the electron neutrino appearance in a muon neutrino beam and the new high-precision measurements of the mixing angle theta13 by the reactor experiments have led to a re-evaluation of the expected sensitivity to the oscillation parameters, relative to what was given in the original T2K proposal. For this reason the new physics potential of T2K for 7.8 x 10**21 p.o.t. and for a data exposure 3 times larger than it's expected to be reachable with accelerator and beam line upgrades in 2026 before the start of operation of the next generation of long-baseline neutrino oscillation experiments will also be described in the text. In particular the last challenging scenario opens the door to the possibility to obtain, under some conditions, a 3 sigma measurement excluding sin(deltaCP= 0.

  13. Strong spin-orbit fields and Dyakonov-Perel spin dephasing in supported metallic films

    Science.gov (United States)

    Long, Nguyen H.; Mavropoulos, Phivos; Bauer, David S. G.; Zimmermann, Bernd; Mokrousov, Yuriy; Blügel, Stefan

    2016-11-01

    Spin dephasing by the Dyakonov-Perel mechanism in metallic films deposited on insulating substrates is revealed, and quantitatively examined by means of density functional calculations combined with a kinetic equation. The surface-to-substrate asymmetry, probed by the metal wave functions in thin films, is found to produce strong spin-orbit fields and a fast Larmor precession, giving a dominant contribution to spin decay over the Elliott-Yafet spin relaxation up to a thickness of 70 nm. The spin dephasing is oscillatory in time with a rapid (subpicosecond) initial decay. However, parts of the Fermi surface act as spin traps, causing a persistent tail signal lasting 1000 times longer than the initial decay time. It is also found that the decay depends on the direction of the initial spin polarization, resulting in a spin-dephasing anisotropy of 200% in the examined cases.

  14. Dephasing and diffusion on the alveolar surface

    Science.gov (United States)

    Buschle, L. R.; Kurz, F. T.; Kampf, T.; Wagner, W. L.; Duerr, J.; Stiller, W.; Konietzke, P.; Wünnemann, F.; Mall, M. A.; Wielpütz, M. O.; Schlemmer, H. P.; Ziener, C. H.

    2017-02-01

    We propose a surface model of spin dephasing in lung tissue that includes both susceptibility and diffusion effects to provide a closed-form solution of the Bloch-Torrey equation on the alveolar surface. The nonlocal susceptibility effects of the model are validated against numerical simulations of spin dephasing in a realistic lung tissue geometry acquired from synchotron-based μ CT data sets of mouse lung tissue, and against simulations in the well-known Wigner-Seitz model geometry. The free induction decay is obtained in dependence on microscopic tissue parameters and agrees very well with in vivo lung measurements at 1.5 Tesla to allow a quantification of the local mean alveolar radius. Our results are therefore potentially relevant for the clinical diagnosis and therapy of pulmonary diseases.

  15. Anharmonic quantum contribution to vibrational dephasing

    OpenAIRE

    Barik, Debashis; Ray, Deb Shankar

    2004-01-01

    Based on a quantum Langevin equation and its corresponding Hamiltonian within a c-number formalism we calculate the vibrational dephasing rate of a cubic oscillator. It is shown that leading order quantum correction due to anharmonicity of the potential makes a significant contribution to the rate and the frequency shift. We compare our theoretical estimates with those obtained from experiments for small diatomics $N_2$, $O_2$ and $CO$.

  16. Optical dephasing of triply ionized rare earths in transparent glass ceramics containing LaF3 nanocrystals.

    Science.gov (United States)

    Zheng, Hairong; Zhang, Xiangyu; Gao, Dangli; Meltzer, Richard S

    2008-03-01

    Optical dephasing of Pr3+ and Tm3+ ions doped in transparent oxyfluoride glass ceramics was studied with the two-pulse photon echo technique. It was found that the dephasing time of rare earth ions is dramatically less in nanocrystals embedded in a glass matrix than in bulk crystals. A quasi-linear temperature dependence obtained at low temperatures proved that the long-range interaction of the ions inside the nanocrystals with the two level systems of the glass matrix dominates the optical dephasing. The local thermal effect in glass ceramics containing nanocrystals elevates the local temperature, which results in the reduction of optical dephasing time. For Tm(3+)-doped glass ceramics, the elevation of local temperature induced by the irradiation of excitation laser even quenched the photon echo signals in the experimental study.

  17. Sensitivity of the T2K accelerator-based neutrino experiment with an Extended run to $20\\times10^{21}$ POT

    CERN Document Server

    Abe, K; Antonova, M; Aoki, S; Ariga, A; Autiero, D; Ban, S; Barbi, M; Barker, G J; Barr, G; Bartet-Friburg, P; Batkiewicz, M; Berardi, V; Berkman, S; Bhadra, S; Bienstock, S; Blondel, A; Bolognesi, S; Bordoni, S; Boyd, S B; Brailsford, D; Bravar, A; Bronner, C; Avanzini, M Buizza; Calland, R G; Campbell, T; Cao, S; Cartwright, S L; Castillo, R; Catanesi, M G; Cervera, A; Cherdack, D; Chikuma, N; Christodoulou, G; Clifton, A; Coleman, J; Collazuol, G; Coplowe, D; Cremonesi, L; Dabrowska, A; De Rosa, G; Dealtry, T; Denner, P F; Dennis, S R; Densham, C; Dewhurst, D; Di Lodovico, F; Di Luise, S; Dolan, S; Drapier, O; Duffy, K E; Dumarchez, J; Dziewiecki, M; Emery-Schrenk, S; Ereditato, A; Feusels, T; Finch, A J; Fiorentini, G A; Friend, M; Fujii, Y; Fukuda, D; Fukuda, Y; Furmanski, A P; Galymov, V; Garcia, A; Giganti, C; Gizzarelli, F; Gonin, M; Grant, N; Hadley, D R; Haegel, L; Haigh, M D; Hansen, D; Harada, J; Hartz, M; Hasegawa, T; Hastings, N C; Hayashino, T; Hayato, Y; Helmer, R L; Hierholzer, M; Hillairet, A; Hiraki, T; Hiramoto, A; Hirota, S; Hogan, M; Holeczek, J; Hosomi, F; Huang, K; Ichikawa, A K; Ikeda, M; Imber, J; Insler, J; Intonti, R A; Ishida, T; Ishii, T; Iwai, E; Iwamoto, K; Izmaylov, A; Jamieson, B; Jiang, M; Johnson, S; Jo, J H; Jonsson, P; Jung, C K; Kabirnezhad, M; Kaboth, A C; Kajita, T; Kakuno, H; Kameda, J; Karlen, D; Karpikov, I; Katori, T; Kearns, E; Khabibullin, M; Khotjantsev, A; Kim, H; Kim, J; King, S; Kisiel, J; Knight, A; Knox, A; Kobayashi, T; Koch, L; Koga, T; Konaka, A; Kondo, K; Kopylov, A; Kormos, L L; Korzenev, A; Koshio, Y; Kropp, W; Kudenko, Y; Kurjata, R; Kutter, T; Lagoda, J; Lamont, I; Lamoureux, M; Larkin, E; Lasorak, P; Laveder, M; Lawe, M; Lindner, T; Liptak, Z J; Litchfield, R P; Li, X; Longhin, A; Lopez, J P; Lou, T; Ludovici, L; Lu, X; Magaletti, L; Mahn, K; Malek, M; Manly, S; Marino, A D; Martin, J F; Martins, P; Martynenko, S; Maruyama, T; Matveev, V; Mavrokoridis, K; Ma, W Y; Mazzucato, E; McCarthy, M; McCauley, N; McFarland, K S; McGrew, C; Mefodiev, A; Metelko, C; Mezzetto, M; Mijakowski, P; Minamino, A; Mineev, O; Mine, S; Missert, A; Miura, M; Moriyama, S; Mueller, Th A; Myslik, J; Nakadaira, T; Nakahata, M; Nakamura, K G; Nakamura, K; Nakamura, K D; Nakanishi, Y; Nakayama, S; Nakaya, T; Nakayoshi, K; Nantais, C; Nielsen, C; Nirkko, M; Nishikawa, K; Nishimura, Y; Novella, P; Nowak, J; O'Keeffe, H M; Ohta, R; Okumura, K; Okusawa, T; Oryszczak, W; Oser, S M; Ovsyannikova, T; Owen, R A; Oyama, Y; Palladino, V; Palomino, J L; Paolone, V; Patel, N D; Pavin, M; Payne, D; Perkin, J D; Petrov, Y; Pickard, L; Pickering, L; Guerra, E S Pinzon; Pistillo, C; Popov, B; Posiadala-Zezula, M; Poutissou, J -M; Poutissou, R; Przewlocki, P; Quilain, B; Radermacher, T; Radicioni, E; Ratoff, P N; Ravonel, M; Rayner, M A M; Redij, A; Reinherz-Aronis, E; Riccio, C; Rojas, P; Rondio, E; Roth, S; Rubbia, A; Rychter, A; Sacco, R; Sakashita, K; Sánchez, F; Scantamburlo, E; Scholberg, K; Schwehr, J; Scott, M; Seiya, Y; Sekiguchi, T; Sekiya, H; Sgalaberna, D; Shah, R; Shaikhiev, A; Shaker, F; Shaw, D; Shiozawa, M; Shirahige, T; Short, S; Smy, M; Sobczyk, J T; Sobel, H; Sorel, M; Southwell, L; Steinmann, J; Stewart, T; Stowell, P; Suda, Y; Suvorov, S; Suzuki, A; Suzuki, S Y; Suzuki, Y; Tacik, R; Tada, M; Takeda, A; Takeuchi, Y; Tanaka, H K; Tanaka, H A; Terhorst, D; Terri, R; Thakore, T; Thompson, L F; Tobayama, S; Toki, W; Tomura, T; Touramanis, C; Tsukamoto, T; Tzanov, M; Uchida, Y; Vagins, M; Vallari, Z; Vasseur, G; Wachala, T; Walter, C W; Wark, D; Warzycha, W; Wascko, M O; Weber, A; Wendell, R; Wilkes, R J; Wilking, M J; Wilkinson, C; Wilson, J R; Wilson, R J; Yamada, Y; Yamamoto, K; Yamamoto, M; Yanagisawa, C; Yano, T; Yen, S; Yershov, N; Yokoyama, M; Yoo, J; Yoshida, K; Yuan, T; Yu, M; Zalewska, A; Zalipska, J; Zambelli, L; Zaremba, K; Ziembicki, M; Zimmerman, E D; Zito, M; Żmuda, J

    2016-01-01

    Recent measurements at the T2K experiment indicate that CP violation in neutrino mixing may be observed in the future by long-baseline neutrino oscillation experiments. We explore the physics program of an extension to the currently approved T2K running of $7.8\\times 10^{21}$ protons-on-target to $20\\times 10^{21}$ protons-on-target,aiming at initial observation of CP violation with 3$\\,\\sigma$ or higher significance for the case of maximum CP violation. With accelerator and beam line upgrades, as well as analysis improvements, this program would occur before the next generation of long-baseline neutrino oscillation experiments that are expected to start operation in 2026.

  18. Suppression of dephasing by qubit motion in superconducting circuits

    Science.gov (United States)

    Averin, D. V.; Hu, K.; Zhong, Y. P.; Song, C.; Wang, H.; Han, S.

    We suggest and demonstrate a protocol which suppresses dephasing due to the low-frequency noise by qubit motion, i.e., transfer of the logical qubit of information in a system of n >= 2 physical qubits. The protocol requires only the nearest-neighbor coupling and is applicable to different qubit structures. Motion of a logical qubit limits the correlation time of the effective noise seen by this qubit and suppresses its decoherence rate. This effect is qualitatively similar to the dynamic decoupling, but relies on the different resource: additional physical qubits, not extra control pulses. In this respect, suggested protocol can serve as the basis for an alternative approach to scalable quantum circuits. We further analyze its effectiveness against noises with arbitrary correlations. Our analysis, together with experiments using up to three superconducting qubits, shows that for the realistic uncorrelated noises, qubit motion increases the dephasing time of the logical qubit as √{ n}. In general, the protocol provides a diagnostic tool for measurements of the noise correlations. This work was supported by the National Basic Research Program of China (2014CB921200, 2012CB927404), US NSF Grants PHY-1314758 and PHY-1314861, the National Natural Science Foundation of China, and Zhejiang Provincial Natural Science Foundation.

  19. Orbital hyperfine interaction and qubit dephasing in carbon nanotube quantum dots

    Science.gov (United States)

    Palyi, Andras; Csiszar, Gabor

    2015-03-01

    Hyperfine interaction (HF) is of key importance for the functionality of solid-state quantum information processing, as it affects qubit coherence and enables nuclear-spin quantum memories. In this work, we complete the theory of the basic hyperfine interaction mechanisms (Fermi contact, dipolar, orbital) in carbon nanotube quantum dots by providing a theoretical description of the orbital HF. We find that orbital HF induces an interaction between the nuclear spins of the nanotube lattice and the valley degree of freedom of the electrons confined in the quantum dot. We show that the resulting nuclear-spin-electron-valley interaction (i) is approximately of Ising type, (ii) is essentially local, in the sense that an effective atomic interaction strength can be defined, and (iii) has a strength that is comparable to the combined strength of Fermi contact and dipolar interactions. We argue that orbital HF provides a new decoherence mechanism for single-electron valley qubits and spin-valley qubits in a range of multi-valley materials. We explicitly evaluate the corresponding inhomogeneous dephasing time T2* for a nanotube-based valley qubit. We acknowledge funding from the EU Marie Curie CIG-293834, OTKA Grant PD 100373, and EU ERC Starting Grant CooPairEnt 258789. AP is supported by the Janos Bolyai Scholarship of the Hungarian Academy of Sciences.

  20. OS044. Morphological differences in murine placenta detected by magneticresonance imaging measurements of T2 relaxation times in mouse models ofpreeclampsia.

    Science.gov (United States)

    Bobek, G; Stait-Gardner, T; Surmon, L; Makris, A; Price, W S; Hennessy, A

    2012-07-01

    We have demonstrated that morphologically distinct regions of the murine placenta can be detected by magnetic resonance imaging (MRI), with image contrast arising from the variation in T2 relaxation times between regions and dependent upon blood flow. Previous studies of human placenta by other groups have shown a homogeneous tissue with correlation of relaxation times with gestational age and a trend for shorter relaxation times in pregnancies complicated by preeclampsia and fetal growth restriction. The ability to detect morphological changes and alterations in blood flow in experimental models of preeclampsia would be a significant boost in understanding the relationship between abnormal placental implantation, reduced placental perfusion, inflammatory cytokines, angiogenic molecules and other factors that may play a role in the syndrome. The aim of this study was to investigate whether morphological changes or abnormalities can be detected by T2 mapping in the placenta of mice subject to two experimental models of preeclampsia (reduced uterine perfusion pressure (RUPP) model and TNF-α induced model). Pregnant C57BL/6JArc mice were, on day 13.5 of gestation, either subject to a unilateral ligation of the right uterine artery (RUPP) (n=2) or given an infusion of TNF-α by subcutaneous insertion of a mini-osmotic pump primed to deliver 500ng/kg/day for 4days (n=2). Controls were normal pregnant (n=2), sham-operated (n=1) or saline infused animals(n=1). MRI images were acquired on anaesthetised mice on day 17.5 of gestation using a Bruker Avance 11.7 Tesla wide-bore spectrometer with micro-imaging probe capable of generating gradients of 0.45T/m. T2 measurements were acquired using an MSME sequence protocol (Bruker MSME-T2-map) with an in-plane resolution of 0.1-0.2mm. Matlab was used to generate R2 (i.e.,1/T2) maps from the acquired data with the T2 values being calculated from selected regions of interest from 2-6 individual placenta from each mouse. Differences

  1. Relaxation and Dephasing in a Two-Electron 13C Nanotube Double Quantum Dot

    DEFF Research Database (Denmark)

    Churchill, H O H; Kuemmeth, Ferdinand; Harlow, J W;

    2009-01-01

    We use charge sensing of Pauli blockade (including spin and isospin) in a two-electron 13C nanotube double quantum dot to measure relaxation and dephasing times. The relaxation time T1 first decreases with a parallel magnetic field and then goes through a minimum in a field of 1.4 T. We attribute...

  2. Quantitative study of MR T1 and T2 relaxation times and 1 HMRS in gray matter of normal adult brain

    Institute of Scientific and Technical Information of China (English)

    范国光; 吴振华; 潘诗农; 郭启勇

    2003-01-01

    Objective To evaluate magnetic resonance (MR) Imaging and 1 H magnetic resonance spectroscopy (1 HMRS) in the study of normal biochemical process of the brain, as well as differentiation of normal senile brain from cerebral diseases related to senility. Methods One hundred and eighty healthy adult volunteers were selected for MR examination and 60 other healthy subjects for 1 HMRS examination. Ages of subjects ranged from 18 to 80 years. They were divided into six age groups. A 0.35 T superconductive MR system was used to perform MR examination. Point resolved spectroscopy sequence was required for 1 HMRS. The metabolites in the spectra included: N-acetylaspartate (NAA), choline compounds (CHO), creatine compounds (CR), myo-inositol (MI), glutamate and glutamine (Glu-n). Results In 180 cases of MR, the shortest T2 relaxation time occurred in the deep gray matter within the same age group while the length of T1 relaxation time was ordered from low to high compared to age groups. T2 relaxation time decreased as age increased. The peaks, ordered from high to low, were as follows in 60 cases of 1 HMRS: NAA, CR, CHO, MI, Glu-n. The ratios of NAA/CR and Glu-n/CR were higher in the senile age group, while that of MI/CR was lower. The ratio of CHO/CR was increased as age decreased. The ratio of NAA/CR and MI/CR gradually decreased in relation to movement from the anterior to the posterior part of the brain; the ratio of CHO/CR was highest in the occipital cortex. Correlation of T1 relaxation time and partial metabolite ratios to age were present in gray matter.Conclusions Quantitative studies of MR T1 and T2 relaxation times and 1 HMRS are essential to evaluation of normal myelinization processes, neuronal integrity and age-related biochemical changes in the brain.

  3. Interaction induced dephasing of excitons in wide ZnSe/ZnMgSe single quantum wells

    DEFF Research Database (Denmark)

    Wagner, Hans Peter; Schätz, A.; Maier, R.;

    1998-01-01

    The dephasing of excitons in wide ZnSe/Zn0.94Mg0.06Se single quantum wells (SQW) is investigated by spectrally resolved, time integrated four-wave mixing (FWM). Simultaneous excitation of Is center-of-mass quantized heavy-hole and light-hole excition states leads to pronounced quantum beats. Pola...

  4. Evaluation of small ({<=}2 cm) dysplastic nodules and well-differentiated hepatocellular carcinomas with ferucarbotran-enhanced MRI in a 1.0-T MRI unit: Utility of T2*-weighted gradient echo sequences with an intermediate-echo time

    Energy Technology Data Exchange (ETDEWEB)

    Tonan, Tatsuyuki [Department of Radiology, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011 (Japan); Fujimoto, Kiminori [Department of Radiology, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011 (Japan)], E-mail: kimichan@med.kurume-u.ac.jp; Azuma, Sanae [Department of Radiology, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011 (Japan); Ono, Noriyuki [Department of Internal Medicine, Chikugo City Hospital, Chikugo (Japan); Matsushita, Sunao [Department of Radiology, Chikugo City Hospital, 917-1 Izumi, Chikugo 833-0041 (Japan); Kojiro, Masamichi [Department of Pathology, Kurume University School of Medicine, Kurume (Japan); Hayabuchi, Naofumi [Department of Radiology, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011 (Japan)

    2007-10-15

    Purpose: To evaluate the detectability and signal intensities of small ({<=}2 cm) dysplastic nodules (DNs) and well-differentiated hepatocellular carcinomas (w-HCCs) by T2*-weighted gradient echo (GRE) sequences using an intermediate echo-time (TE) with ferucarbotran in a 1.0-T magnetic resonance imaging (MRI) unit. Materials and methods: Pathologically confirmed DNs (n = 13) and w-HCCs (n = 31) with a median largest dimension of 1.1 cm were scanned using ferucarbotran-enhanced MRI. Conventional T2*-weighted GRE sequences (conventional-T2*-GRE: repetition time, 280 ms; echo time, 14 ms; flip angle, 60 deg.) and specific T2*-weighted GRE sequences using an intermediate-TE (specific-T2*-GRE: repetition time, 140 ms; echo time, 8 ms; flip angle, 30 deg.) were obtained before and after ferucarbotran administration. Two independent observers scored all nodules for visibility and assigned confidence level scores to their observations. To assess the effect of ferucarbotran, the tumor-liver signal contrast-to-noise ratio (tumor-liver-CNR) was also calculated for detected nodules by the same two observers with consensus. Results: There was good interobserver agreement regarding the presence of nodules for both sequence types. Qualitative and quantitative analyses indicated that specific-T2*GRE sequences were superior to conventional-T2*-GRE sequences for detecting DNs and w-HCCs with hypointense signals. The tumor-liver-CNR of DNs was significantly different between specific-T2*-GRE sequences and conventional-T2*-GRE sequences (Mann-Whitney test, P < 0.001). Both qualitative and quantitative analyses indicated that conventional-T2*-GRE sequences were superior to specific-T2*-GRE sequences for detecting w-HCCs with heterogeneous and hyperintense signals. Conclusion: Specific-T2*-GRE sequences with ferucarbotran are useful for detecting DNs and w-HCCs that produce hypointense signals on a 1.0-T MRI unit.

  5. Spacetime Conformal Fluctuations and Quantum Dephasing

    CERN Document Server

    Bonifacio, Paolo M

    Any quantum system interacting with a complex environment undergoes decoherence. Empty space is filled with vacuum energy due to matter fields in their ground state and represents an underlying environment that any quantum particle has to cope with. In particular quantum gravity vacuum fluctuations should represent a universal source of decoherence. To study this problem we employ a stochastic approach that models spacetime fluctuations close to the Planck scale by means of a classical, randomly fluctuating metric (random gravity framework). We enrich the classical scheme for metric perturbations over a curved background by also including matter fields and metric conformal fluctuations. We show in general that a conformally modulated metric induces dephasing as a result of an effective nonlinear newtonian potential obtained in the appropriate nonrelativistic limit of a minimally coupled Klein-Gordon field. The special case of vacuum fluctuations is considered and a quantitative estimate of the expected effect...

  6. Spacetime Conformal Fluctuations and Quantum Dephasing

    Science.gov (United States)

    Bonifacio, Paolo M.

    2009-06-01

    Any quantum system interacting with a complex environment undergoes decoherence. Empty space is filled with vacuum energy due to matter fields in their ground state and represents an underlying environment that any quantum particle has to cope with. In particular quantum gravity vacuum fluctuations should represent a universal source of decoherence. To study this problem we employ a stochastic approach that models spacetime fluctuations close to the Planck scale by means of a classical, randomly fluctuating metric (random gravity framework). We enrich the classical scheme for metric perturbations over a curved background by also including matter fields and metric conformal fluctuations. We show in general that a conformally modulated metric induces dephasing as a result of an effective nonlinear newtonian potential obtained in the appropriate nonrelativistic limit of a minimally coupled Klein-Gordon field. The special case of vacuum fluctuations is considered and a quantitative estimate of the expected effect deduced. Secondly we address the question of how conformal fluctuations could physically arise. By applying the random gravity framework we first show that standard GR seems to forbid spontaneous conformal metric modulations. Finally we argue that a different result follows within scalar-tensor theories of gravity such as e.g. Brans-Dicke theory. In this case a conformal modulation of the metric arises naturally as a result of the fluctuations in the Brans-Dicke field and quantum dephasing of a test particle is expected to occur. For large negative values of the coupling parameter the conformal fluctuations may also contribute to alleviate the well known problem of the large zero point energy due to quantum matter fields.

  7. A spectroscopic system for time- and space-resolved studies of impurities on the EXTRAP-T2 reversed field pinch

    Science.gov (United States)

    Sallander, J.

    1998-06-01

    The radial distribution of impurity line emission in the EXTRAP-T2 reversed field pinch (RFP) is studied with a five viewing chord, absolutely calibrated, spectrometer system. The light is analyzed with a single 0.5 m grating spectrometer. Different parts of the entrance slit are used for different channels. This arrangement makes it possible to use the system over a wide wavelength range, from 2500 to 6500 Å, without having to recalibrate the relative sensitivity for the different channels. The rather short plasma pulses of 10-15 ms require a high time resolution. The use of photomultiplier tubes provides a time resolution of 10 μs which is limited by the transient recorders used. The result is a robust, low-cost system that produces reliable measurements of the radial dependence of emission from a wide range of impurity ions.

  8. Geometric dephasing in zero-field magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Jones, J.A. [Oxford Centre for Molecular Sciences, University of Oxford, New Chemistry Laboratory, South Parks Road, Oxford OX1 3QT]|[Merton College, Oxford OX1 4JD (United Kingdom); Pines, A. [Lawrence Berkeley Laboratory and Department of Chemistry, University of California, Berkeley, California 94720 (United States)

    1997-02-01

    Geometric phases acquired randomly can give rise to coherence dephasing in nuclear spin systems, equivalent to spin relaxation. We calculate the form and extent of this geometric dephasing in a number of model systems involving the motion of {sup 131}Xe nuclei in shaped containers. The dephasing is calculated in two ways: first, using an analytical treatment of the diffusive motion of individual nuclei, and second, using ensemble averaged propagators. The effects of applying additional magnetic fields to these systems are discussed briefly. {copyright} {ital 1997 American Institute of Physics.}

  9. Measurement of geometric dephasing using a superconducting qubit

    Science.gov (United States)

    Berger, S.; Pechal, M.; Kurpiers, P.; Abdumalikov, A. A.; Eichler, C.; Mlynek, J. A.; Shnirman, A.; Gefen, Yuval; Wallraff, A.; Filipp, S.

    2015-01-01

    A quantum system interacting with its environment is subject to dephasing, which ultimately destroys the information it holds. Here we use a superconducting qubit to experimentally show that this dephasing has both dynamic and geometric origins. It is found that geometric dephasing, which is present even in the adiabatic limit and when no geometric phase is acquired, can either reduce or restore coherence depending on the orientation of the path the qubit traces out in its projective Hilbert space. It accompanies the evolution of any system in Hilbert space subjected to noise. PMID:26515812

  10. Comparison of apparent diffusion coefficient and T2 relaxation time variation patterns in assessment of age and disc level related intervertebral disc changes.

    Science.gov (United States)

    Wu, Nan; Liu, Hao; Chen, Jun; Zhao, Luo; Zuo, Wei; Ming, Yue; Liu, Sen; Liu, Jiaqi; Su, Xinlin; Gao, Baoxiang; Tang, Zhiquan; Qiu, Guixing; Ma, Guolin; Wu, Zhihong

    2013-01-01

    To compare the variation patterns of ADC and T2 values in different age and intervertebral disc (IVD) levels, thus to identify their sensitivities in assessing age and disc level related IVDs changes. The T2 and ADC values were recorded from 345 IVDs of 69 volunteers. Kendall's correlation analysis was used to identify the relationship between age and T2/ADC mean values respectively. The one-way analysis of variance (ANOVA) with post hoc analysis was then applied to test the differences of T2 and ADC values among different IVD levels and age groups, followed by linear regression analysis between age (45 years) and T2/ADC mean values. This study was approved by the Ethics Committee of the Chinese Academy of Medical Sciences and the Peking Union Medical College Hospital. Significant negative correlation was observed between age and T2/ADC mean values. The T2 and ADC values showed significant differences among IVD levels and among age groups except for T2 values in age group 1 (25-34 years) and group 2 (35-44 years), and for ADC values at L1-2 level. Both T2 and ADC values showed significant differences between young (age45 years) at each IVD level. A linear relationship was observed between age and T2/ADC mean values in the elderly group as well as in the young group for the ADC mean values, while no such tendency was identified in the young group for the T2 mean values. ADC values may be a more sensitive parameter than T2 in assessing age and disc level related intervertebral disc changes.

  11. Comparison of apparent diffusion coefficient and T2 relaxation time variation patterns in assessment of age and disc level related intervertebral disc changes.

    Directory of Open Access Journals (Sweden)

    Nan Wu

    Full Text Available PURPOSE: To compare the variation patterns of ADC and T2 values in different age and intervertebral disc (IVD levels, thus to identify their sensitivities in assessing age and disc level related IVDs changes. MATERIALS AND METHODS: The T2 and ADC values were recorded from 345 IVDs of 69 volunteers. Kendall's correlation analysis was used to identify the relationship between age and T2/ADC mean values respectively. The one-way analysis of variance (ANOVA with post hoc analysis was then applied to test the differences of T2 and ADC values among different IVD levels and age groups, followed by linear regression analysis between age (45 years and T2/ADC mean values. This study was approved by the Ethics Committee of the Chinese Academy of Medical Sciences and the Peking Union Medical College Hospital. RESULTS: Significant negative correlation was observed between age and T2/ADC mean values. The T2 and ADC values showed significant differences among IVD levels and among age groups except for T2 values in age group 1 (25-34 years and group 2 (35-44 years, and for ADC values at L1-2 level. Both T2 and ADC values showed significant differences between young (age45 years at each IVD level. A linear relationship was observed between age and T2/ADC mean values in the elderly group as well as in the young group for the ADC mean values, while no such tendency was identified in the young group for the T2 mean values. CONCLUSIONS: ADC values may be a more sensitive parameter than T2 in assessing age and disc level related intervertebral disc changes.

  12. High-field 1H T1 and T2 NMR relaxation time measurements of H2O in homeopathic preparations of quartz, sulfur, and copper sulfate

    Science.gov (United States)

    Baumgartner, Stephan; Wolf, Martin; Skrabal, Peter; Bangerter, Felix; Heusser, Peter; Thurneysen, André; Wolf, Ursula

    2009-09-01

    Quantitative meta-analyses of randomized clinical trials investigating the specific therapeutic efficacy of homeopathic remedies yielded statistically significant differences compared to placebo. Since the remedies used contained mostly only very low concentrations of pharmacologically active compounds, these effects cannot be accounted for within the framework of current pharmacology. Theories to explain clinical effects of homeopathic remedies are partially based upon changes in diluent structure. To investigate the latter, we measured for the first time high-field (600/500 MHz) 1H T1 and T2 nuclear magnetic resonance relaxation times of H2O in homeopathic preparations with concurrent contamination control by inductively coupled plasma mass spectrometry (ICP-MS). Homeopathic preparations of quartz (10 c-30 c, n = 21, corresponding to iterative dilutions of 100-10-100-30), sulfur (13 x-30 x, n = 18, 10-13-10-30), and copper sulfate (11 c-30 c, n = 20, 100-11-100-30) were compared to n = 10 independent controls each (analogously agitated dilution medium) in randomized and blinded experiments. In none of the samples, the concentration of any element analyzed by ICP-MS exceeded 10 ppb. In the first measurement series (600 MHz), there was a significant increase in T1 for all samples as a function of time, and there were no significant differences between homeopathic potencies and controls. In the second measurement series (500 MHz) 1 year after preparation, we observed statistically significant increased T1 relaxation times for homeopathic sulfur preparations compared to controls. Fifteen out of 18 correlations between sample triplicates were higher for controls than for homeopathic preparations. No conclusive explanation for these phenomena can be given at present. Possible hypotheses involve differential leaching from the measurement vessel walls or a change in water molecule dynamics, i.e., in rotational correlation time and/or diffusion. Homeopathic preparations

  13. Pure electron-electron dephasing in percolative aluminum ultrathin film grown by molecular beam epitaxy.

    Science.gov (United States)

    Lin, Shih-Wei; Wu, Yue-Han; Chang, Li; Liang, Chi-Te; Lin, Sheng-Di

    2015-01-01

    We have successfully grown ultrathin continuous aluminum film by molecular beam epitaxy. This percolative aluminum film is single crystalline and strain free as characterized by transmission electron microscopy and atomic force microscopy. The weak anti-localization effect is observed in the temperature range of 1.4 to 10 K with this sample, and it reveals that, for the first time, the dephasing is purely caused by electron-electron inelastic scattering in aluminum.

  14. Vibrational dephasing and frequency shifts of hydrogen-bonded pyridine-water complexes

    Science.gov (United States)

    Kalampounias, A. G.; Tsilomelekis, G.; Boghosian, S.

    2015-01-01

    In this paper we present the picosecond vibrational dynamics and Raman shifts of hydrogen-bonded pyridine-water complexes present in aqueous solutions in a wide concentration range from dense to extreme dilute solutions. We studied the vibrational dephasing and vibrational frequency modulation by calculating time correlation functions of vibrational relaxation by fits in the frequency domain. The concentration induced variations in bandwidths, band frequencies and characteristic dephasing times have been estimated and interpreted as effects due to solute-solvent interactions. The time-correlation functions of vibrational dephasing were obtained for the ring breathing mode of both "free" and hydrogen-bonded pyridine molecules and it was found that sufficiently deviate from the Kubo model. There is a general agreement in the whole concentration range with the modeling proposed by the Rothschild approach, which applies to complex liquids. The results have shown that the reorientation of pyridine aqueous solutions is very slow and hence in both scattering geometries only vibrational dephasing is probed. It is proposed that the spectral changes depend on the perturbations induced by the dynamics of the water molecules in the first hydration cell and water in bulk, while at extreme dilution conditions, the number of bulk water molecules increases and the interchange between molecules belonging to the first hydration cell may not be the predominant modulation mechanism. The evolution of several parameters, such as the characteristic times, the percentage of Gaussian character in the peak shape and the a parameter are indicative of drastic variations at extreme dilution revealing changes in the vibrational relaxation of the pyridine complexes in the aqueous environment. The higher dilution is correlated to diffusion of water molecules into the reference pyridine system in agreement with the jump diffusion model, while at extreme dilutions, almost all pyridine molecules are

  15. Vibrational dephasing and frequency shifts of hydrogen-bonded pyridine-water complexes.

    Science.gov (United States)

    Kalampounias, A G; Tsilomelekis, G; Boghosian, S

    2015-01-25

    In this paper we present the picosecond vibrational dynamics and Raman shifts of hydrogen-bonded pyridine-water complexes present in aqueous solutions in a wide concentration range from dense to extreme dilute solutions. We studied the vibrational dephasing and vibrational frequency modulation by calculating time correlation functions of vibrational relaxation by fits in the frequency domain. The concentration induced variations in bandwidths, band frequencies and characteristic dephasing times have been estimated and interpreted as effects due to solute-solvent interactions. The time-correlation functions of vibrational dephasing were obtained for the ring breathing mode of both "free" and hydrogen-bonded pyridine molecules and it was found that sufficiently deviate from the Kubo model. There is a general agreement in the whole concentration range with the modeling proposed by the Rothschild approach, which applies to complex liquids. The results have shown that the reorientation of pyridine aqueous solutions is very slow and hence in both scattering geometries only vibrational dephasing is probed. It is proposed that the spectral changes depend on the perturbations induced by the dynamics of the water molecules in the first hydration cell and water in bulk, while at extreme dilution conditions, the number of bulk water molecules increases and the interchange between molecules belonging to the first hydration cell may not be the predominant modulation mechanism. The evolution of several parameters, such as the characteristic times, the percentage of Gaussian character in the peak shape and the a parameter are indicative of drastic variations at extreme dilution revealing changes in the vibrational relaxation of the pyridine complexes in the aqueous environment. The higher dilution is correlated to diffusion of water molecules into the reference pyridine system in agreement with the jump diffusion model, while at extreme dilutions, almost all pyridine molecules are

  16. On the non-equilibrium dynamics of dissipative Rydberg gases in the presence of dephasing noise

    CERN Document Server

    Levi, Emanuele; Lesanovsky, Igor

    2016-01-01

    In the presence of strong dephasing noise the dynamics of Rydberg gases becomes effectively classical, due to the rapid decay of quantum superpositions between atomic levels. Recently a great deal of attention has been devoted to the stochastic dynamics that emerges in that limit, revealing several interesting features, including kinetically-constrained glassy behaviour, self-similarity and aggregation effects. However, the non-equilibrium physics of these systems, in particular in the regime where coherent and dissipative processes contribute on equal footing, is yet far from being understood. To explore this we study the dynamics of a small one-dimensional Rydberg lattice gas subject to dephasing noise by numerically integrating the quantum Master equation. We find indications that the main features observed in the strongly dissipative limit persist when the dissipation is not strong enough to annihilate quantum coherences at the dynamically relevant time scales. These features include a power law growth of...

  17. Size dependence of electron spin dephasing in InGaAs quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Y. Q.; Puttisong, Y.; Buyanova, I. A.; Chen, W. M. [Department of Physics, Chemistry and Biology, Linköping University, S-581 83 Linköping (Sweden); Yang, X. J.; Subagyo, A.; Sueoka, K.; Murayama, A. [Graduate School of Information Science and Technology, Hokkaido University, Kita 14, Nishi 9, Kita-ku, Sapporo 060-0814 (Japan)

    2015-03-02

    We investigate ensemble electron spin dephasing in self-assembled InGaAs/GaAs quantum dots (QDs) of different lateral sizes by employing optical Hanle measurements. Using low excitation power, we are able to obtain a spin dephasing time T{sub 2}{sup *} (in the order of ns) of the resident electron after recombination of negative trions in the QDs. We show that T{sub 2}{sup *} is determined by the hyperfine field arising from the frozen fluctuation of nuclear spins, which scales with the size of QDs following the Merkulov-Efros-Rosen model. This scaling no longer holds in large QDs, most likely due to a breakdown in the lateral electron confinement.

  18. 1H metabolite relaxation times at 3.0 tesla: Measurements of T1 and T2 values in normal brain and determination of regional differences in transverse relaxation.

    Science.gov (United States)

    Träber, Frank; Block, Wolfgang; Lamerichs, Rolf; Gieseke, Jürgen; Schild, Hans H

    2004-05-01

    To measure 1H relaxation times of cerebral metabolites at 3 T and to investigate regional variations within the brain. Investigations were performed on a 3.0-T clinical whole-body magnetic resonance (MR) system. T2 relaxation times of N-acetyl aspartate (NAA), total creatine (tCr), and choline compounds (Cho) were measured in six brain regions of 42 healthy subjects. T1 relaxation times of these metabolites and of myo-inositol (Ins) were determined in occipital white matter (WM), the frontal lobe, and the motor cortex of 10 subjects. T2 values of all metabolites were markedly reduced with respect to 1.5 T in all investigated regions. T2 of NAA was significantly (P motor cortex (247 +/- 13 msec) than in occipital WM (301 +/- 18 msec). T2 of the tCr methyl resonance showed a corresponding yet less pronounced decrease (162 +/- 16 msec vs. 178 +/- 9 msec, P = 0.021). Even lower T2 values for all metabolites were measured in the basal ganglia. Metabolite T1 relaxation times at 3.0 T were not significantly different from the values at 1.5 T. Transverse relaxation times of the investigated cerebral metabolites exhibit an inverse proportionality to magnetic field strength, and especially T2 of NAA shows distinct regional variations at 3 T. These can be attributed to differences in relative WM/gray matter (GM) contents and to local paramagnetism. Copyright 2004 Wiley-Liss, Inc.

  19. Copper plasmonics and catalysis: role of electron-phonon interactions in dephasing localized surface plasmons.

    Science.gov (United States)

    Sun, Qi-C; Ding, Yuchen; Goodman, Samuel M; Funke, Hans H; Nagpal, Prashant

    2014-11-07

    Copper metal can provide an important alternative for the development of efficient, low-cost and low-loss plasmonic nanoparticles, and selective nanocatalysts. However, poor chemical stability and lack of insight into photophysics and plasmon decay mechanisms has impeded study. Here, we use smooth conformal ALD coating on copper nanoparticles to prevent surface oxidation, and study dephasing time for localized surface plasmons on different sized copper nanoparticles. Using dephasing time as a figure of merit, we elucidate the role of electron-electron, electron-phonon, impurity, surface and grain boundary scattering on the decay of localized surface plasmon waves. Using our quantitative analysis and different temperature dependent measurements, we show that electron-phonon interactions dominate over other scattering mechanisms in dephasing plasmon waves. While interband transitions in copper metal contributes substantially to plasmon losses, tuning surface plasmon modes to infrared frequencies leads to a five-fold enhancement in the quality factor. These findings demonstrate that conformal ALD coatings can improve the chemical stability for copper nanoparticles, even at high temperatures (>300 °C) in ambient atmosphere, and nanoscaled copper is a good alternative material for many potential applications in nanophotonics, plasmonics, catalysis and nanoscale electronics.

  20. Enhanced electron dephasing in three-dimensional topological insulators

    Science.gov (United States)

    Liao, Jian; Ou, Yunbo; Liu, Haiwen; He, Ke; Ma, Xucun; Xue, Qi-Kun; Li, Yongqing

    2017-07-01

    Study of the dephasing in electronic systems is not only important for probing the nature of their ground states, but also crucial to harnessing the quantum coherence for information processing. In contrast to well-studied conventional metals and semiconductors, it remains unclear which mechanism is mainly responsible for electron dephasing in three-dimensional topological insulators (TIs). Here, we report on using weak antilocalization effect to measure the dephasing rates in highly tunable (Bi,Sb)2Te3 thin films. As the transport is varied from a bulk-conducting regime to surface-dominant transport, the dephasing rate is observed to evolve from a linear temperature dependence to a sublinear power-law dependence. Although the former is consistent with the Nyquist electron-electron interactions commonly seen in ordinary 2D systems, the latter leads to enhanced electron dephasing at low temperatures and is attributed to the coupling between the surface states and the localized charge puddles in the bulk of 3D TIs.

  1. 铁和老年斑在阿尔茨海默病转基因小鼠脑内的沉积及其对磁共振T2弛豫时间的影响%Iron and senile plaques deposition in transgenic mouse model of Alzheimer's disease and influence on MR T2 relaxation times

    Institute of Scientific and Technical Information of China (English)

    王东; 张临洪; 徐威; 杜小霞; 湛言强; 张苏明

    2010-01-01

    目的 观察老年斑和铁在阿尔茨海默病(AD)转基因小鼠脑内皮质和海马处的沉积及其对磁共振活体扫描T2弛豫时间的影响.方法 2、4、6、8、10、12、14、16月龄的AD转基因小鼠各2只,分为幼龄组、成龄组和老龄组,8月龄野生型C57BL/6J小鼠2只作为对照,依次进行磁共振活体扫描,测量皮质、海马、丘脑、胼胝体、纹状体等结构的T2弛豫时间,扫描完成后,进行铁和老年斑的组织学染色,计算皮质和海马处老年斑的数目及含量、铁颗粒的数目及含量.结果 各组皮质及海马T2弛豫时间(ms)分别为:野生组:49.5±2.1、51.6±1.1;幼龄组(2、4月龄):49.7±0.5、50.7±0.7;成龄组(6、8、10月龄):47.2±0.8、47.7±0.9;老龄组(12、14、16月龄):44.6±0.8、45.3±0.4.各组皮质及海马T2弛豫时间差异有统计学意义(皮质F=18.620,海马F=67.925,均P<0.01).组间比较示成龄组较幼龄组(皮质q=4.284,海马q=7.902;均P<0.01)及野生组(皮质q=4.424,P<0.05,海马q=11.450,P<0.01)小鼠皮质及海马T2弛豫时间缩短;而老龄组较成龄组小鼠皮质及海马T2弛豫时间缩短(皮质q=4.812,海马q=7.034,均P<0.01).组织学染色示4月龄转基因小鼠皮质和海马开始出现老年斑的沉积,6月龄开始出现铁的沉积,并且随着小鼠月龄的增加,皮质和海马处老年斑和铁的数目及含量均明显增加.老年斑和铁的沉积具有明显的正相关(r=0.931,P<0.01),老年斑的含量、铁的含量与T2弛豫时间均具有明显的负相关(分别r=-0.884、-0.827,均P<0.01).结论 老年斑和铁的沉积可能共同影响T2弛豫时间,提示T2弛豫时间可以作为早期诊断AD和抗痴呆药物筛选的一个敏感性指标.%Objective To observe senile plaque and iron deposition in cortex and hippocampus of the Alzheimer's disease ( AD ) transgenic mice and investigate their influence on T2 relaxation time.Method All AD transgeic mice were divided into three groups

  2. Correlation between brain volume change and T2 relaxation time induced by dehydration and rehydration: Implications for monitoring atrophy in clinical studies

    Directory of Open Access Journals (Sweden)

    Kunio Nakamura

    2014-01-01

    Our results show that pseudo-T2 may be used in conjunction with the measures of brain volume to distinguish reversible water fluctuations and irreversible brain tissue loss (atrophy and to investigate disease mechanisms related to neuro-inflammation, e.g., in multiple sclerosis, where edema-related water fluctuations may occur with disease activity and anti-inflammatory treatment.

  3. meta-DENSE complex acquisition for reduced intravoxel dephasing

    Science.gov (United States)

    Aletras, Anthony H.; Arai, Andrew E.

    2004-08-01

    Displacement encoding with stimulated echoes (DENSE) with a meta-DENSE readout and RF phase cycling to suppress the STEAM anti-echo is described for reducing intravoxel dephasing signal loss. This RF phase cycling scheme, when combined with existing meta-DENSE suppression of the T1 recovering signal, yields higher quality DENSE myocardial strain maps. Phantom and human images are provided to demonstrate the technique, which is capable of acquiring phase contrast displacement encoded images at low encoding gradient strengths providing better spatial resolution and less signal loss due to intravoxel dephasing than prior methods.

  4. Effect of short-term unloading on T2 relaxation time in the lumbar intervertebral disc—in vivo magnetic resonance imaging study at 3.0 tesla

    Science.gov (United States)

    Stelzeneder, David; Kovács, Balázs K.; Goed, Sabine; Welsch, Goetz H.; Hirschfeld, Clemens; Paternostro-Sluga, Tatjana; Friedrich, Klaus M.; Mamisch, Tallal C.; Trattnig, Siegfried

    2012-01-01

    Background context Diurnal changes in T2 values, indicative for changes in water content, have been reported in the lumbar intervertebral discs. However, data concerning short-term T2 changes are missing. Purpose The purpose of this study was to investigate the short-term effects of unloading on T2 values in lumbar intervertebral discs in vivo. Study design Experimental study with repeated measurements of lumbar discs T2 relaxation time during a period of 38 minutes of supine posture. Patient sample Forty-one patients with acute or chronic low back pain (visual analog scale ≥3). Outcome measures T2 relaxation time in the intervertebral disc, lumbar lordosis angle, and intervertebral disc height. Methods Forty-one patients (mean age, 41.6 years) were investigated in the supine position using a 3-tesla magnetic resonance system. Sagittal T2 mapping was performed immediately after unloading and after a mean delay of 38 minutes. No patient movement was allowed between the measurements. One region of interest (ROI) was manually placed in both the anterior and the posterior annulus fibrosus (AF) and three ROIs in the nucleus pulposus (NP). Results There was a statistically significant decrease in the anterior NP (−2.7 ms; p<.05) and an increase in T2 values in the posterior AF (+3.5 ms; p<.001). Discs with initially low T2 values in the NP showed minor increase in the posterior AF (+1.6 ms; p<.05), whereas a major increase in the posterior AF was found in discs with initially high T2 values in the NP (+6.8 ms; p=.001). Patients examined in the morning showed no differences, but those investigated in the afternoon showed a decrease in the anterior NP (−5.3 ms; p<.05) and an increase in the posterior AF (+7.8 ms; p=.002). No significant differences were observed in other regions. Correlation analysis showed moderate correlations between the time of investigation and T2 changes in the posterior AF (r=0.46; p=.002). Conclusions A shift of water from the anterior to

  5. Intersublevel polaron dephasing in self-assembled quantum dots

    NARCIS (Netherlands)

    E.A. Zibik,; Grange, T.; Carpenter, B. A.; Ferreira, R.; Bastard, G.; Vinh, N. Q.; Phillips, P. J.; Steer, M. J.; M. Hopkinson,; J.W. Cockburn,; Skolnick, M. S.; L.R. Wilson,

    2008-01-01

    Polaron dephasing processes are investigated in InAs/GaAs dots using far-infrared transient four wave mixing (FWM) spectroscopy. We observe an oscillatory behavior in the FWM signal shortly (< 5 ps) after resonant excitation of the lowest energy conduction band transition due to coherent acoustic

  6. Binding-energy distribution and dephasing of localized biexcitons

    DEFF Research Database (Denmark)

    Langbein, Wolfgang Werner; Hvam, Jørn Märcher; Umlauff, M.

    1997-01-01

    We report on the binding energy and dephasing of localized biexciton states in narrow ZnSe multiple quantum wells. The measured binding-energy distribution of the localized biexcitons shows a width of 2.2 meV centered at 8.5 meV, and is fairly independent of the exciton localization energy. In four...

  7. Conservatively treated knee injury is associated with knee cartilage matrix degeneration measured with MRI-based T2 relaxation times: data from the osteoarthritis initiative.

    Science.gov (United States)

    Hofmann, Felix C; Neumann, Jan; Heilmeier, Ursula; Joseph, Gabby B; Nevitt, Michael C; McCulloch, Charles E; Link, Thomas M

    2017-08-29

    To investigate the association of cartilage degeneration with previous knee injuries not undergoing surgery, determined by morphologic and quantitative 3-T magnetic resonance imaging (MRI). We performed a nested cross-sectional study of right knee MRIs from participants in the Osteoarthritis Initiative (OAI) aged 45-79 with baseline Kellgren-Lawrence score of 0-2. Cases were 142 right knees of patients with self-reported history of injury limiting the ability to walk for at least 2 days. Controls were 426 right knees without history of injury, frequency-matched to cases on age, BMI, gender, KL scores and race (1:3 ratio). Cases and controls were compared using covariate-adjusted linear regression analysis, with the outcomes of region-specific T2 mean, laminar analysis and heterogeneity measured by texture analysis to investigate early cartilage matrix abnormalities and the Whole-Organ Magnetic Resonance Imaging Score (WORMS) to investigate morphologic knee lesions. Compared to control subjects, we found significantly higher mean T2 values in the injury [lateral tibia (28.10 ms vs. 29.11 ms, p = 0.001), medial tibia (29.70 ms vs. 30.40 ms, p = 0.014) and global knee cartilage (32.73 ms vs. 33.29 ms, p = 0.005)]. Injury subjects also had more heterogeneous cartilage as measured by GLCM texture contrast, variance and entropy (p  0.05). A history of knee injury not treated surgically is associated with higher and more heterogeneous T2 values, but not with morphologic knee abnormalities. Our findings suggest that significant, conservatively treated knee injuries are associated with permanent cartilage matrix abnormalities.

  8. Measurements of neutral hydrogen profiles on the EXTRAP-T2 reversed-field pinch from time-resolved ? line emission

    Science.gov (United States)

    Sallander, J.; Hedqvist, A.; Rachlew-Källne, E.

    1998-09-01

    The investigations of the radial distributions of 0953-4075/31/17/015/img2 emission from the EXTRAP-T2 reversed-field pinch (RFP) plasma show that the emission profile varies a lot, even during one plasma discharge. At central electron temperatures of about 150 eV it was expected that the 0953-4075/31/17/015/img2 emission should emerge from the plasma centre. In comparison, 0953-4075/31/17/015/img4 is always observed to radiate from the centre. Our measurements of 0953-4075/31/17/015/img2 emission have, however, shown that this is not always the case, the emission often comes from the plasma edge. The analysis of the measurements has led us to conclude that the edge emission comes from charge-exchange recombination with neutral hydrogen near the carbon first wall. These observations provide a way to estimate the change in neutral hydrogen density during local plasma-wall interaction.

  9. Characterization of the collagen component of cartilage repair tissue of the talus with quantitative MRI: comparison of T2 relaxation time measurements with a diffusion-weighted double-echo steady-state sequence (dwDESS)

    Energy Technology Data Exchange (ETDEWEB)

    Kretzschmar, M.; Hainc, N.; Studler, U. [University Hospital Basel, Department of Radiology, Basel (Switzerland); Bieri, O. [University Hospital Basel, Division of Radiological Physics, Basel (Switzerland); Miska, M. [University Hospital, Department of Orthopedics, Heidelberg (Germany); Wiewiorski, M.; Valderrabano, V. [University Hospital Basel, Department of Orthopedic Surgery, Basel (Switzerland)

    2015-04-01

    The purpose of this study was to characterize the collagen component of repair tissue (RT) of the talus after autologous matrix-induced chondrogenesis (AMIC) using quantitative T2 and diffusion-weighted imaging. Mean T2 values and diffusion coefficients of AMIC-RT and normal cartilage of the talus of 25 patients with posttraumatic osteochondral lesions and AMIC repair were compared in a cross-sectional design using partially spoiled steady-state free precession (pSSFP) for T2 quantification, and diffusion-weighted double-echo steady-state (dwDESS) for diffusion measurement. RT and cartilage were graded with modified Noyes and MOCART scores on morphological sequences. An association between follow-up interval and quantitative MRI measures was assessed using multivariate regression, after stratifying the cohort according to time interval between surgery and MRI. Mean T2 of the AMIC-RT and cartilage were 43.1 ms and 39.1 ms, respectively (p = 0.26). Mean diffusivity of the RT (1.76 μm{sup 2}/ms) was significantly higher compared to normal cartilage (1.46 μm{sup 2}/ms) (p = 0.0092). No correlation was found between morphological and quantitative parameters. RT diffusivity was lowest in the subgroup with follow-up >28 months (p = 0.027). Compared to T2-mapping, dwDESS demonstrated greater sensitivity in detecting differences in the collagen matrix between AMIC-RT and cartilage. Decreased diffusivity in patients with longer follow-up times may indicate an increased matrix organization of RT. (orig.)

  10. T2 mapping in patellar chondromalacia.

    Science.gov (United States)

    Ruiz Santiago, Fernando; Pozuelo Calvo, Rocío; Almansa López, Julio; Guzmán Álvarez, Luis; Castellano García, María Del Mar

    2014-06-01

    To study the correlation between the T2 relaxation times of the patellar cartilage and morphological MRI findings of chondromalacia. This prospective study comprises 50 patients, 27 men and 23 women suffering of anterior knee pain (mean age: 29.7, SD 8.3 years; range: 16-45 years). MRI of 97 knees were performed in these patients at 1.5T magnet including sagittal T1, coronal intermediate, axial intermediate fat sat and T2 mapping. Chondromalacia was assessed using a modified version of Noyes classification. The relaxation time, T2, was studied segmenting the full thickness of the patellar cartilage in 12 areas: 4 proximal (external facet-proximal-lateral (EPL), external facet-proximal-central (EPC), internal facet-proximal-central (IPC), internal facet-proximal-medial (IPM), 4 in the middle section (external facet-middle-lateral (EML), external facet-middle-central (EMC), internal facet-middle-central (IMC), internal facet-middle-medial (IMM) and 4 distal (external facet-distal-lateral (EDL), external facet-distal-central (EDC), internal facet-distal-central (IDC), internal facet-distal-medial (IDM). T2 values showed a significant increase in mild chondromalacia regarding normal cartilage in most of the cartilage areas (pchondromalacia was characterized by a fall of T2 relaxation times with loss of statistical significant differences in comparison with normal cartilage, except in EMC and IMC, where similar values as mild chondromalacia were maintained (pchondromalacia to more severe degrees is associated to a new drop of T2 relaxation times approaching basal values in most of the areas of the patellar cartilage, except in the central area of the middle section, where T2 values remain increased. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  11. Inhomogeneous dephasing masks coherence lifetimes in ensemble measurements.

    Science.gov (United States)

    Pelzer, Kenley M; Griffin, Graham B; Gray, Stephen K; Engel, Gregory S

    2012-04-28

    broadening in the time domain), this important fact has been left out of recent discussions of spectroscopic measurements of energy transport in photosynthesis. In general, these discussions have compared single-system theoretical models to whole-ensemble laboratory measurements without addressing the effect of inhomogeneous dephasing. Our work addresses this distinction between single system and ensemble averaged observations, and shows that the ensemble averaging inherent in many experiments leads to an underestimation of coherence lifetimes in individual systems.

  12. Control quantum evolution speed of a single dephasing qubit for arbitrary initial states via periodic dynamical decoupling pulses

    Science.gov (United States)

    Song, Ya-Ju; Tan, Qing-Shou; Kuang, Le-Man

    2017-01-01

    We investigate the possibility to control quantum evolution speed of a single dephasing qubit for arbitrary initial states by the use of periodic dynamical decoupling (PDD) pulses. It is indicated that the quantum speed limit time (QSLT) is determined by initial and final quantum coherence of the qubit, as well as the non-Markovianity of the system under consideration during the evolution when the qubit is subjected to a zero-temperature Ohmic-like dephasing reservoir. It is shown that final quantum coherence of the qubit and the non-Markovianity of the system can be modulated by PDD pulses. Our results show that for arbitrary initial states of the dephasing qubit with non-vanishing quantum coherence, PDD pulses can be used to induce potential acceleration of the quantum evolution in the short-time regime, while PDD pulses can lead to potential speedup and slow down in the long-time regime. We demonstrate that the effect of PDD on the QSLT for the Ohmic or sub-Ohmic spectrum (Markovian reservoir) is much different from that for the super-Ohmic spectrum (non-Markovian reservoir). PMID:28272546

  13. Control quantum evolution speed of a single dephasing qubit for arbitrary initial states via periodic dynamical decoupling pulses

    Science.gov (United States)

    Song, Ya-Ju; Tan, Qing-Shou; Kuang, Le-Man

    2017-03-01

    We investigate the possibility to control quantum evolution speed of a single dephasing qubit for arbitrary initial states by the use of periodic dynamical decoupling (PDD) pulses. It is indicated that the quantum speed limit time (QSLT) is determined by initial and final quantum coherence of the qubit, as well as the non-Markovianity of the system under consideration during the evolution when the qubit is subjected to a zero-temperature Ohmic-like dephasing reservoir. It is shown that final quantum coherence of the qubit and the non-Markovianity of the system can be modulated by PDD pulses. Our results show that for arbitrary initial states of the dephasing qubit with non-vanishing quantum coherence, PDD pulses can be used to induce potential acceleration of the quantum evolution in the short-time regime, while PDD pulses can lead to potential speedup and slow down in the long-time regime. We demonstrate that the effect of PDD on the QSLT for the Ohmic or sub-Ohmic spectrum (Markovian reservoir) is much different from that for the super-Ohmic spectrum (non-Markovian reservoir).

  14. Spatially selective T2 and T2 ∗ measurement with line-scan echo-planar spectroscopic imaging

    Science.gov (United States)

    Chen, Nan-kuei; Oshio, Koichi; Panych, Lawrence P.; Rybicki, Frank J.; Mulkern, Robert V.

    2004-11-01

    Line-scan echo planar spectroscopic imaging (LSEPSI) is applied to quickly measure the T2 and T2 ∗ relaxation time constants in pre-selected 2D or 3D regions. Results from brain imaging studies at 3 T suggest that the proposed method may prove valuable for both basic research (e.g., quantifying the changes of T2/T2 ∗ values in functional MRI with blood oxygenation level-dependent contrast) and clinical studies (e.g., measuring the T2' shortening due to iron deposition). The proposed spatially selective T2 and T2 ∗ mapping technique is especially well suited for studies, where T2/T2 ∗ quantification needs to be performed dynamically in a pre-selected 2D or 3D region.

  15. Dephasing mechanisms of optical transitions in rare-earth-doped transparent ceramics

    Science.gov (United States)

    Kunkel, Nathalie; Bartholomew, John; Welinski, Sacha; Ferrier, Alban; Ikesue, Akio; Goldner, Philippe

    2016-11-01

    We identify and analyze dephasing mechanisms that broaden the optical transitions of rare-earth ions in randomly oriented transparent ceramics. The study examines the narrow F70↔D50 transition of Eu3 + dopants in a series of Y2O3 ceramic samples prepared under varying conditions. We characterize the temperature and magnetic field dependence of the homogeneous linewidth, as well as long-term spectral diffusion on time scales up to 1 s. The results highlight significant differences between samples with differing thermal treatments and Zr4 + additive concentrations. In particular, several distinct magnetic interactions from defect centers are observed, which are clearly distinguished from the broadening due to interactions with two-level systems and phonons. By minimizing the broadening due to the different defect centers, linewidths of the order of 4 kHz are achieved for all samples. The linewidths are limited by temperature-dependent interactions and by an interaction that is yet to be identified. Although the homogeneous linewidth can be narrowed further in these ceramic samples, the broadening is now comparable to the linewidths achieved in rare-earth-ion-doped single crystals. Thus, this work emphasizes the usefulness of studying ceramics to gain insights into dephasing mechanisms relevant to single crystals and suggests that ceramics may be an interesting alternative for applications in classical and quantum information processing.

  16. Diffusion-mediated dephasing in the dipole field around a single spherical magnetic object.

    Science.gov (United States)

    Buschle, Lukas R; Kurz, Felix T; Kampf, Thomas; Triphan, Simon M F; Schlemmer, Heinz-Peter; Ziener, Christian Herbert

    2015-11-01

    In this work, the time evolution of the free induction decay caused by the local dipole field of a spherical magnetic perturber is analyzed. The complicated treatment of the diffusion process is replaced by the strong-collision-approximation that allows a determination of the free induction decay in dependence of the underlying microscopic tissue parameters such as diffusion coefficient, sphere radius and susceptibility difference. The interplay between susceptibility- and diffusion-mediated effects yields several dephasing regimes of which, so far, only the classical regimes of motional narrowing and static dephasing for dominant and negligible diffusion, respectively, were extensively examined. Due to the asymmetric form of the dipole field for spherical objects, the free induction decay exhibits a complex component in contradiction to the cylindrical case, where the symmetric local dipole field only causes a purely real induction decay. Knowledge of the shape of the corresponding frequency distribution is necessary for the evaluation of more sophisticated pulse sequences and a detailed understanding of the off-resonance distribution allows improved quantification of transverse relaxation.

  17. Quantum non-equilibrium dynamics of Rydberg gases in the presence of dephasing noise of different strengths

    Science.gov (United States)

    Levi, Emanuele; Gutiérrez, Ricardo; Lesanovsky, Igor

    2016-09-01

    In the presence of strong dephasing noise the dynamics of Rydberg gases becomes effectively classical, due to the rapid decay of quantum superpositions between atomic levels. Recently a great deal of attention has been devoted to the stochastic dynamics that emerges in that limit, revealing several interesting features, including kinetically constrained glassy behaviour, self-similarity and aggregation effects. However, the non-equilibrium physics of these systems, in particular in the regime where coherent and dissipative processes contribute on equal footing, is yet far from being understood. To explore this we study the dynamics of a small one-dimensional Rydberg lattice gas subject to dephasing noise by numerically integrating the quantum master equation. We interpolate between the coherent and the strongly dephased regime by defining a generalised concept of a blockade length. We find indications that the main features observed in the strongly dissipative limit persist when the dissipation is not strong enough to annihilate quantum coherences at the dynamically relevant time scales. These features include the existence of a time-dependent Rydberg blockade radius, and a growth of the density of excitations which is compatible with the power-law behaviour expected in the classical limit.

  18. Spin Dephasing as a Probe of Mode Temperature, Motional State Distributions, and Heating Rates in a 2D Ion Crystal

    CERN Document Server

    Sawyer, Brian C; Bollinger, John J

    2014-01-01

    We employ spin-dependent optical dipole forces to characterize the transverse center-of-mass (COM) motional mode of a two-dimensional Wigner crystal of hundreds of $^9$Be$^+$. By comparing the measured spin dephasing produced by the spin-dependent force with the predictions of a semiclassical dephasing model, we obtain absolute mode temperatures in excellent agreement with both the Doppler laser cooling limit and measurements obtained from a previously published technique (B. C. Sawyer et al. Phys. Rev. Lett. \\textbf{108}, 213003 (2012)). Furthermore, the structure of the dephasing histograms allows for discrimination between initial thermal and coherent states of motion. We also apply the techniques discussed here to measure, for the first time, the ambient heating rate of the COM mode of a 2D Coulomb crystal in a Penning trap. This measurement places an upper limit on the anomalous single-ion heating rate due to electric field noise from the trap electrode surfaces of $\\frac{d\\bar{n}}{dt}\\sim 5$ s$^{-1}$ fo...

  19. T2 mapping in patellar chondromalacia

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz Santiago, Fernando, E-mail: ferusan12@gmail.com [Department of Radiology, Traumatology Hospital, University Hospital Virgen de las Nieves, Granada (Spain); Pozuelo Calvo, Rocío [Department of Rehabilitation and Physical therapy, Traumatology Hospital, University Hospital Virgen de las Nieves, Granada (Spain); Almansa López, Julio [Department of Physic, University Hospital Virgen de las Nieves, Granada (Spain); Guzmán Álvarez, Luis; Castellano García, María del Mar [Department of Radiology, Traumatology Hospital, University Hospital Virgen de las Nieves, Granada (Spain)

    2014-06-15

    Objective: To study the correlation between the T2 relaxation times of the patellar cartilage and morphological MRI findings of chondromalacia. Methods: This prospective study comprises 50 patients, 27 men and 23 women suffering of anterior knee pain (mean age: 29.7, SD 8.3 years; range: 16–45 years). MRI of 97 knees were performed in these patients at 1.5 T magnet including sagittal T1, coronal intermediate, axial intermediate fat sat and T2 mapping. Chondromalacia was assessed using a modified version of Noyes classification. The relaxation time, T2, was studied segmenting the full thickness of the patellar cartilage in 12 areas: 4 proximal (external facet–proximal–lateral (EPL), external facet–proximal–central (EPC), internal facet–proximal–central (IPC), internal facet–proximal–medial (IPM), 4 in the middle section (external facet–middle–lateral (EML), external facet–middle–central (EMC), internal facet–middle–central (IMC), internal facet–middle–medial (IMM) and 4 distal (external facet–distal–lateral (EDL), external facet–distal–central (EDC), internal facet–distal–central (IDC), internal facet–distal–medial (IDM). Results: T2 values showed a significant increase in mild chondromalacia regarding normal cartilage in most of the cartilage areas (p < 0.05), except in the internal distal facet (IDC and IDM), EPC, EDL, and IMM. Severe chondromalacia was characterized by a fall of T2 relaxation times with loss of statistical significant differences in comparison with normal cartilage, except in EMC and IMC, where similar values as mild chondromalacia were maintained (p < 0.05). Conclusions: Steepest increase in T2 values of patellar cartilage occurs in early stages of patellar cartilage degeneration. Progression of morphologic changes of chondromalacia to more severe degrees is associated to a new drop of T2 relaxation times approaching basal values in most of the areas of the patellar cartilage, except in the

  20. Orthogonal separable Hamiltonian systems on T2

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper we characterize the Liouvillian integrable orthogonal separable Hamiltonian systems on T2 for a given metric, and prove that the Hamiltonian flow on any compact level hypersurface has zero topological entropy. Furthermore, by examples we show that the integrable Hamiltonian systems on T2 can have complicated dynamical phenomena. For instance they can have several families of invariant tori, each family is bounded by the homoclinic-loop-like cylinders and heteroclinic-loop-like cylinders. As we know, it is the first concrete example to present the families of invariant tori at the same time appearing in such a complicated way.

  1. Dephasing-assisted transport: quantum networks and biomolecules

    Energy Technology Data Exchange (ETDEWEB)

    Plenio, M B [QOLS, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BW (United Kingdom); Huelga, S F [School of Physics, Astronomy and Mathematics, University of Hertfordshire, Hatfield, Herts AL10 9AB (United Kingdom)], E-mail: m.plenio@imperial.ac.uk

    2008-11-15

    Transport phenomena are fundamental in physics. They allow for information and energy to be exchanged between individual constituents of communication systems, networks or even biological entities. Environmental noise will generally hinder the efficiency of the transport process. However, and contrary to intuition, there are situations in classical systems where thermal fluctuations are actually instrumental in assisting transport phenomena. Here we show that, even at zero temperature, transport of excitations across dissipative quantum networks can be enhanced by local dephasing noise. We explain the underlying physical mechanisms behind this phenomenon and propose possible experimental demonstrations in quantum optics. Our results suggest that the presence of entanglement does not play an essential role for energy transport and may even hinder it. We argue that Nature may be routinely exploiting dephasing noise and show that the transport of excitations in simplified models of light harvesting molecules does benefit from such noise assisted processes. These results point toward the possibility for designing optimized structures for transport, for example in artificial nanostructures, assisted by noise.

  2. Explicit formulae for the two way time-transfer in the T2L2 experiment including the J2 contribution to the Earth potential in a relativistic framework

    CERN Document Server

    Minazzoli, Olivier; Samain, Etienne; Exertier, Pierre; Vrancken, Patrick; Guillemot, Philippe

    2010-01-01

    The topic of this paper is to study the two way time-transfer problem between a ground based station and a low orbit Earth's satellite, in the aim of an application to the T2L2 experiment. The sudy is driven in a fully relativistic framework. Because of the rapid increase in clock's precision/measurements, the first term beyond the Earth's potential monopolar term is explicitly taken into account. Explicit formulae, for both the distance and offset problems (definitions in the text) are proposed for the relevant applications.

  3. Dephasing in semiconductor-superconductor structures by coupling to a voltage probe

    DEFF Research Database (Denmark)

    Mortensen, Niels Asger; Jauho, Antti-Pekka; Flensberg, Karsten

    2000-01-01

    We study dephasing in semiconductor-superconductor structures caused by coupling to a voltage probe. We consider structures where the semiconductor consists of two scattering regions between which partial dephasing is possible. As a particular example we consider a situation with a double barrier...... of the conductance when a finite coupling to the voltage probe is taken into account....

  4. Influence of pure dephasing on emission spectra from single photon sources

    DEFF Research Database (Denmark)

    Næsby Rasmussen, Andreas; Skovgård, Troels Suhr; Kristensen, Philip Trøst

    2008-01-01

    We investigate the light-matter interaction of a quantum dot with the electromagnetic field in a lossy microcavity and calculate emission spectra for nonzero detuning and dephasing. It is found that dephasing shifts the intensity of the emission peaks for nonzero detuning. We investigate the char...

  5. The T2K experiment

    Science.gov (United States)

    Abe, K.; Abgrall, N.; Aihara, H.; Ajima, Y.; Albert, J. B.; Allan, D.; Amaudruz, P.-A.; Andreopoulos, C.; Andrieu, B.; Anerella, M. D.; Angelsen, C.; Aoki, S.; Araoka, O.; Argyriades, J.; Ariga, A.; Ariga, T.; Assylbekov, S.; de André, J. P. A. M.; Autiero, D.; Badertscher, A.; Ballester, O.; Barbi, M.; Barker, G. J.; Baron, P.; Barr, G.; Bartoszek, L.; Batkiewicz, M.; Bay, F.; Bentham, S.; Berardi, V.; Berger, B. E.; Berns, H.; Bertram, I.; Besnier, M.; Beucher, J.; Beznosko, D.; Bhadra, S.; Birney, P.; Bishop, D.; Blackmore, E.; Blaszczyk, F. d. M.; Blocki, J.; Blondel, A.; Bodek, A.; Bojechko, C.; Bouchez, J.; Boussuge, T.; Boyd, S. B.; Boyer, M.; Braam, N.; Bradford, R.; Bravar, A.; Briggs, K.; Brinson, J. D.; Bronner, C.; Brook-Roberge, D. G.; Bryant, M.; Buchanan, N.; Budd, H.; Cadabeschi, M.; Calland, R. G.; Calvet, D.; Caravaca Rodríguez, J.; Carroll, J.; Cartwright, S. L.; Carver, A.; Castillo, R.; Catanesi, M. G.; Cavata, C.; Cazes, A.; Cervera, A.; Charrier, J. P.; Chavez, C.; Choi, S.; Chollet, S.; Christodoulou, G.; Colas, P.; Coleman, J.; Coleman, W.; Collazuol, G.; Connolly, K.; Cooke, P.; Curioni, A.; Dabrowska, A.; Danko, I.; Das, R.; Davies, G. S.; Davis, S.; Day, M.; De La Broise, X.; de Perio, P.; De Rosa, G.; Dealtry, T.; Debraine, A.; Delagnes, E.; Delbart, A.; Densham, C.; Di Lodovico, F.; Di Luise, S.; Dinh Tran, P.; Dobson, J.; Doornbos, J.; Dore, U.; Drapier, O.; Druillole, F.; Dufour, F.; Dumarchez, J.; Durkin, T.; Dytman, S.; Dziewiecki, M.; Dziomba, M.; Ellison, B.; Emery, S.; Ereditato, A.; Escallier, J. E.; Escudero, L.; Esposito, L. S.; Faszer, W.; Fechner, M.; Ferrero, A.; Finch, A.; Fisher, C.; Fitton, M.; Flight, R.; Forbush, D.; Frank, E.; Fransham, K.; Fujii, Y.; Fukuda, Y.; Gallop, M.; Galymov, V.; Ganetis, G. L.; Gannaway, F. C.; Gaudin, A.; Gaweda, J.; Gendotti, A.; George, M.; Giffin, S.; Giganti, C.; Gilje, K.; Giomataris, I.; Giraud, J.; Ghosh, A. K.; Golan, T.; Goldhaber, M.; Gomez-Cadenas, J. J.; Gomi, S.; Gonin, M.; Goyette, M.; Grant, A.; Grant, N.; Grañena, F.; Greenwood, S.; Gumplinger, P.; Guzowski, P.; Haigh, M. D.; Hamano, K.; Hansen, C.; Hara, T.; Harrison, P. F.; Hartfiel, B.; Hartz, M.; Haruyama, T.; Hasanen, R.; Hasegawa, T.; Hastings, N. C.; Hastings, S.; Hatzikoutelis, A.; Hayashi, K.; Hayato, Y.; Haycock, T. D. J.; Hearty, C.; Helmer, R. L.; Henderson, R.; Herlant, S.; Higashi, N.; Hignight, J.; Hiraide, K.; Hirose, E.; Holeczek, J.; Honkanen, N.; Horikawa, S.; Hyndman, A.; Ichikawa, A. K.; Ieki, K.; Ieva, M.; Iida, M.; Ikeda, M.; Ilic, J.; Imber, J.; Ishida, T.; Ishihara, C.; Ishii, T.; Ives, S. J.; Iwasaki, M.; Iyogi, K.; Izmaylov, A.; Jamieson, B.; Johnson, R. A.; Joo, K. K.; Jover-Manas, G.; Jung, C. K.; Kaji, H.; Kajita, T.; Kakuno, H.; Kameda, J.; Kaneyuki, K.; Karlen, D.; Kasami, K.; Kasey, V.; Kato, I.; Kawamuko, H.; Kearns, E.; Kellet, L.; Khabibullin, M.; Khaleeq, M.; Khan, N.; Khotjantsev, A.; Kielczewska, D.; Kikawa, T.; Kim, J. Y.; Kim, S.-B.; Kimura, N.; Kirby, B.; Kisiel, J.; Kitching, P.; Kobayashi, T.; Kogan, G.; Koike, S.; Komorowski, T.; Konaka, A.; Kormos, L. L.; Korzenev, A.; Koseki, K.; Koshio, Y.; Kouzuma, Y.; Kowalik, K.; Kravtsov, V.; Kreslo, I.; Kropp, W.; Kubo, H.; Kubota, J.; Kudenko, Y.; Kulkarni, N.; Kurchaninov, L.; Kurimoto, Y.; Kurjata, R.; Kurosawa, Y.; Kutter, T.; Lagoda, J.; Laihem, K.; Langstaff, R.; Laveder, M.; Lawson, T. B.; Le, P. T.; Le Coguie, A.; Le Ross, M.; Lee, K. P.; Lenckowski, M.; Licciardi, C.; Lim, I. T.; Lindner, T.; Litchfield, R. P.; Longhin, A.; Lopez, G. D.; Lu, P.; Ludovici, L.; Lux, T.; Macaire, M.; Magaletti, L.; Mahn, K.; Makida, Y.; Malafis, C. J.; Malek, M.; Manly, S.; Marchionni, A.; Mark, C.; Marino, A. D.; Marone, A. J.; Marteau, J.; Martin, J. F.; Maruyama, T.; Maryon, T.; Marzec, J.; Masliah, P.; Mathie, E. L.; Matsumura, C.; Matsuoka, K.; Matveev, V.; Mavrokoridis, K.; Mazzucato, E.; McCauley, N.; McFarland, K. S.; McGrew, C.; McLachlan, T.; Mercer, I.; Messina, M.; Metcalf, W.; Metelko, C.; Mezzetto, M.; Mijakowski, P.; Miller, C. A.; Minamino, A.; Mineev, O.; Mine, S.; Minvielle, R. E.; Mituka, G.; Miura, M.; Mizouchi, K.; Mols, J.-P.; Monfregola, L.; Monmarthe, E.; Moreau, F.; Morgan, B.; Moriyama, S.; Morris, D.; Muir, A.; Murakami, A.; Muratore, J. F.; Murdoch, M.; Murphy, S.; Myslik, J.; Nagashima, G.; Nakadaira, T.; Nakahata, M.; Nakamoto, T.; Nakamura, K.; Nakayama, S.; Nakaya, T.; Naples, D.; Nelson, B.; Nicholls, T. C.; Nishikawa, K.; Nishino, H.; Nitta, K.; Nizery, F.; Nowak, J. A.; Noy, M.; Obayashi, Y.; Ogitsu, T.; Ohhata, H.; Okamura, T.; Okumura, K.; Okusawa, T.; Ohlmann, C.; Olchanski, K.; Openshaw, R.; Oser, S. M.; Otani, M.; Owen, R. A.; Oyama, Y.; Ozaki, T.; Pac, M. Y.; Palladino, V.; Paolone, V.; Paul, P.; Payne, D.; Pearce, G. F.; Pearson, C.; Perkin, J. D.; Pfleger, M.; Pierre, F.; Pierrepont, D.; Plonski, P.; Poffenberger, P.; Poplawska, E.; Popov, B.; Posiadala, M.; Poutissou, J.-M.; Poutissou, R.; Preece, R.; Przewlocki, P.; Qian, W.; Raaf, J. L.; Radicioni, E.; Ramos, K.; Ratoff, P.; Raufer, T. M.; Ravonel, M.; Raymond, M.; Retiere, F.; Richards, D.; Ritou, J.-L.; Robert, A.; Rodrigues, P. A.; Rondio, E.; Roney, M.; Rooney, M.; Ross, D.; Rossi, B.; Roth, S.; Rubbia, A.; Ruterbories, D.; Sacco, R.; Sadler, S.; Sakashita, K.; Sanchez, F.; Sarrat, A.; Sasaki, K.; Schaack, P.; Schmidt, J.; Scholberg, K.; Schwehr, J.; Scott, M.; Scully, D. I.; Seiya, Y.; Sekiguchi, T.; Sekiya, H.; Sheffer, G.; Shibata, M.; Shimizu, Y.; Shiozawa, M.; Short, S.; Siyad, M.; Smith, D.; Smith, R. J.; Smy, M.; Sobczyk, J.; Sobel, H.; Sooriyakumaran, S.; Sorel, M.; Spitz, J.; Stahl, A.; Stamoulis, P.; Star, O.; Statter, J.; Stawnyczy, L.; Steinmann, J.; Steffens, J.; Still, B.; Stodulski, M.; Stone, J.; Strabel, C.; Strauss, T.; Sulej, R.; Sutcliffe, P.; Suzuki, A.; Suzuki, K.; Suzuki, S.; Suzuki, S. Y.; Suzuki, Y.; Suzuki, Y.; Swierblewski, J.; Szeglowski, T.; Szeptycka, M.; Tacik, R.; Tada, M.; Tadepalli, A. S.; Taguchi, M.; Takahashi, S.; Takeda, A.; Takenaga, Y.; Takeuchi, Y.; Tanaka, H. A.; Tanaka, K.; Tanaka, M.; Tanaka, M. M.; Tanimoto, N.; Tashiro, K.; Taylor, I. J.; Terashima, A.; Terhorst, D.; Terri, R.; Thompson, L. F.; Thorley, A.; Thorpe, M.; Toki, W.; Tomaru, T.; Totsuka, Y.; Touramanis, C.; Tsukamoto, T.; Tvaskis, V.; Tzanov, M.; Uchida, Y.; Ueno, K.; Usseglio, M.; Vacheret, A.; Vagins, M.; Van Schalkwyk, J. F.; Vanel, J.-C.; Vasseur, G.; Veledar, O.; Vincent, P.; Wachala, T.; Waldron, A. V.; Walter, C. W.; Wanderer, P. J.; Ward, M. A.; Ward, G. P.; Wark, D.; Warner, D.; Wascko, M. O.; Weber, A.; Wendell, R.; Wendland, J.; West, N.; Whitehead, L. H.; Wikström, G.; Wilkes, R. J.; Wilking, M. J.; Williamson, Z.; Wilson, J. R.; Wilson, R. J.; Wong, K.; Wongjirad, T.; Yamada, S.; Yamada, Y.; Yamamoto, A.; Yamamoto, K.; Yamanoi, Y.; Yamaoka, H.; Yanagisawa, C.; Yano, T.; Yen, S.; Yershov, N.; Yokoyama, M.; Zalewska, A.; Zalipska, J.; Zaremba, K.; Ziembicki, M.; Zimmerman, E. D.; Zito, M.; Zmuda, J.; T2K Collaboration

    2011-12-01

    The T2K experiment is a long baseline neutrino oscillation experiment. Its main goal is to measure the last unknown lepton sector mixing angle θ13 by observing νe appearance in a νμ beam. It also aims to make a precision measurement of the known oscillation parameters, Δm232 and sin22θ23, via νμ disappearance studies. Other goals of the experiment include various neutrino cross-section measurements and sterile neutrino searches. The experiment uses an intense proton beam generated by the J-PARC accelerator in Tokai, Japan, and is composed of a neutrino beamline, a near detector complex (ND280), and a far detector (Super-Kamiokande) located 295 km away from J-PARC. This paper provides a comprehensive review of the instrumentation aspect of the T2K experiment and a summary of the vital information for each subsystem.

  6. Results from T2K

    CERN Document Server

    Haigh, Martin David

    2015-01-01

    The Tokai to Kamioka (T2K) experiment uses a beam of muon neutrinos, produced at the J-PARC facility on the east coast of Japan, to study neutrino oscillations driven by the $\\Delta m_{\\textrm{atm}}^{2}$ mass splitting. A suite of near detectors located 280~m from the secondary beam source samples the unoscillated beam, and the Super-Kamiokande water Cherenkov detector samples the beam at a baseline of 295~km, and at a point $2.5^\\circ$ off the beam axis, giving a narrow-band beam centred around 600~MeV. Analyses of the oscillation channels $\

  7. Spectral shift and dephasing of electromagnetically induced transparency in an interacting Rydberg gas

    CERN Document Server

    Han, Jingshan; Li, Wenhui

    2016-01-01

    We perform spectroscopic measurements of electromagnetically induced transparency (EIT) in a strongly interacting Rydberg gas, and observe a significant spectral shift of the transparency from the single-atom EIT resonance as well as a spectral dephasing of the same order. We characterize the shift and dephasing as a function of atomic density, probe Rabi frequency, and principal quantum number of Rydberg states, and demonstrate that the observed spectral shift and dephasing are reduced if the size of a Gaussian atomic cloud is increased. We simulate our experiment with a semi-analytical model, which gives results in good agreement with our experimental data.

  8. Transverse azimuthal dephasing of vortex spin wave in a hot atomic gas

    CERN Document Server

    Shi, Shuai; Zhang, Wei; Zhou, Zhi-Yuan; Dong, Ming-Xin; Liu, Shi-Long; Shi, Bao-Sen; Guo, Guang-Can

    2016-01-01

    Optical fields with orbital angular momentum (OAM) interact with medium have many remarkable properties with its unique azimuthal phase, showing many potential applications in high capacity information processing, high precision measurement etc. The dephasing mechanics of optical fields with OAM in an interface between light and matter plays a vital role in many areas of physics. In this work, we study the transverse azimuthal dephasing of OAM spin wave in a hot atomic gas via OAM storage. The transverse azimuthal phase difference between the control and probe beams is mapped onto the spin wave, which essentially results in dephasing of atomic spin wave. The dephasing of OAM spin wave can be controlled by the parameters of OAM topological charge and beam waist. Our results are helpful for studying OAM light interaction with matter, maybe hold a promise in OAM-based quantum information processing.

  9. B1-insensitive T2 mapping of healthy thigh muscles using a T2-prepared 3D TSE sequence.

    Science.gov (United States)

    Klupp, Elisabeth; Weidlich, Dominik; Schlaeger, Sarah; Baum, Thomas; Cervantes, Barbara; Deschauer, Marcus; Kooijman, Hendrik; Rummeny, Ernst J; Zimmer, Claus; Kirschke, Jan S; Karampinos, Dimitrios C

    2017-01-01

    To propose a T2-prepared 3D turbo spin echo (T2prep 3D TSE) sequence for B1-insensitive skeletal muscle T2 mapping and compare its performance with 2D and 3D multi-echo spin echo (MESE) for T2 mapping in thigh muscles of healthy subjects. The performance of 2D MESE, 3D MESE and the proposed T2prep 3D TSE in the presence of transmit B1 and B0 inhomogeneities was first simulated. The thigh muscles of ten young and healthy subjects were then scanned on a 3 T system and T2 mapping was performed using the three sequences. Transmit B1-maps and proton density fat fraction (PDFF) maps were also acquired. The subjects were scanned three times to assess reproducibility. T2 values were compared among sequences and their sensitivity to B1 inhomogeneities was compared to simulation results. Correlations were also determined between T2 values, PDFF and B1. The left rectus femoris muscle showed the largest B1 deviations from the nominal value (from 54.2% to 92.9%). Significant negative correlations between T2 values and B1 values were found in the left rectus femoris muscle for 3D MESE (r = -0.72, pvariation (RMSCVs) were equal to 3.5% in T2prep 3D TSE, 2.6% in 3D MESE and 2.4% in 2D MESE. Significant differences between T2 values of 3D sequences (T2prep 3D TSE and 3D MESE) and 2D MESE were found in all muscles with the highest values for 2D MESE (pmuscle T2 mapping.

  10. 7 Tesla quantitative hip MRI: T1, T2 and T2* mapping of hip cartilage in healthy volunteers

    Energy Technology Data Exchange (ETDEWEB)

    Lazik, Andrea; Theysohn, Jens M.; Geis, Christina [University Hospital Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Johst, Soeren; Kraff, Oliver [University of Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); Ladd, Mark E. [University Hospital Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); University of Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); German Cancer Research Center (DKFZ), Medical Physics in Radiology, Heidelberg (Germany); Quick, Harald H. [University of Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); University Hospital Essen, High Field and Hybrid MR Imaging, Essen (Germany)

    2016-05-15

    To evaluate the technical feasibility and applicability of quantitative MR techniques (delayed gadolinium-enhanced MRI of cartilage (dGEMRIC), T2 mapping, T2* mapping) at 7 T MRI for assessing hip cartilage. Hips of 11 healthy volunteers were examined at 7 T MRI with an 8-channel radiofrequency transmit/receive body coil using multi-echo sequences for T2 and T2* mapping and a dual flip angle gradient-echo sequence before (T1{sub 0}) and after intravenous contrast agent administration (T1{sub Gd}; 0.2 mmol/kg Gd-DTPA{sup 2-} followed by 0.5 h of walking and 0.5 h of rest) for dGEMRIC. Relaxation times of cartilage were measured manually in 10 regions of interest. Pearson's correlations between R1{sub delta} = 1/T1{sub Gd} - 1/T1{sub 0} and T1{sub Gd} and between T2 and T2* were calculated. Image quality and the delineation of acetabular and femoral cartilage in the relaxation time maps were evaluated using discrete rating scales. High correlations were found between R1{sub delta} and T1{sub Gd} and between T2 and T2* relaxation times (all p < 0.01). All techniques delivered diagnostic image quality, with best delineation of femoral and acetabular cartilage in the T2* maps (mean 3.2 out of a maximum of 4 points). T1, T2 and T2* mapping of hip cartilage with diagnostic image quality is feasible at 7 T. To perform dGEMRIC at 7 T, pre-contrast T1 mapping can be omitted. (orig.)

  11. Binding energy and dephasing of biexcitons in In0.18Ga0.82As/GaAs single quantum wells

    DEFF Research Database (Denmark)

    Borri, Paola; Langbein, Wolfgang Werner; Hvam, Jørn Märcher

    1999-01-01

    Biexciton binding energies and biexciton dephasing in In0.18Ga0.82As/GaAs single quantum wells have been measured by time-integrated and spectrally resolved four-wave mixing. The biexciton binding energy increases from 1.5 to 2.6 meV for well widths increasing from 1 to 4 nm. The ratio between ex...

  12. Pulsed Rydberg four-wave mixing with motion-induced dephasing in a thermal vapor

    CERN Document Server

    Chen, Yi-Hsin; Löw, Robert; Pfau, Tilman

    2015-01-01

    We report on time-resolved pulsed four-wave mixing (FWM) signals in a thermal Rubidium vapor involving a Rydberg state. We observe FWM signals with dephasing times up to 7 ns, strongly dependent on the excitation bandwidth to the Rydberg state. The excitation to the Rydberg state is driven by a pulsed two-photon transition on ns time scales. Combined with a third cw de-excitation laser, a strongly directional and collective emission is generated according to a combination of the phase matching effect and averaging over Doppler classes. In contrast to a previous report [1] using off-resonant FWM, at a resonant FWM scheme we observe additional revivals of the signal shortly after the incident pulse has ended. We infer that this is a revival of motion-induced constructive interference between the coherent emissions of the thermal atoms. The resonant FWM scheme reveals a richer temporal structure of the signals, compared to similar, but off-resonant excitation schemes. A simple explanation lies in the selectivity...

  13. T2 shortening in childhood moyamoya disease

    Energy Technology Data Exchange (ETDEWEB)

    Takanashi, J. [Department of Pediatrics, Faculty of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba-shi 260 (Japan); Sugita, K. [Department of Pediatrics, Faculty of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba-shi 260 (Japan); Tanabe, Y. [Division of Neurology, Chiba Children`s Hospital, 579-1 Heta, Midori-ku, Chiba-shi 266 (Japan); Ito, C. [Division of Neurosurgery, Chiba Children`s Hospital, 579-1 Heta, Midori-ku, Chiba-shi 266 (Japan); Date, H. [Division of Neurosurgery, Chiba Children`s Hospital, 579-1 Heta, Midori-ku, Chiba-shi 266 (Japan); Niimi, H. [Department of Pediatrics, Faculty of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba-shi 260 (Japan)

    1996-05-01

    We examined T2 shortening in six children with infarcts due to moyamoya disease to clarify whether there are characteristic patterns of T2 shortening in the deep grey and white matter. Profound T2 shortening in the deep grey and white matter was observed in the acute stage of infarct in two cases, which changed to high intensity in the chronic stage; in this stage no T2 shortening was demonstrated in any case. Neither haemorrhagic infarction nor calcification was seen on CT or MRI. There could be longitudinally different T2 shortening patterns between infarcts due to moyamoya disease and other disorders. (orig.). With 2 figs., 1 tab.

  14. Application of T2* measurement on gradient echo T2*-weighted imaging in differential diagnosis of intracranial hemorrhage and calcification

    Institute of Scientific and Technical Information of China (English)

    LIU Lan-xiang; YI Hui-ling; HAN Hong-bin; QI Xi-ming

    2012-01-01

    Background Differential diagnosis of intracranial hemorrhage and calcification is a common problem encountered in clinical imaging diagnosis.The purpose of this study was to investigate the feasibility of T2* measurement on gradient echo (GRE) T2*-weighted imaging (T2*WI) in differential diagnosis of intracranial hemorrhage and calcification.Methods Thirty-eight hemorrhagic foci in 18 patients and 11 calcification foci in seven patients were included in this study.The diagnosis of hemorrhage and calcification was confirmed in all cases with enhanced T2* weighted angiography (ESWAN) magnetic resonance imaging (MRI) and CT respectively.The significance for the difference of T2* value between the central and peripheral areas of hemorrhage and calcification lesions was tested with univariate analysis of variance.Results The detection rate of GRE T2*WI on intracranial hemorrhage was 1.9-fold higher than that of CT,especially for the hemorrhage in the brainstem and cerebellum.However,GRE T2*WI was far less sensitive to calcification than CT.There was a significant difference in the T2* value between the central area of hemorrhage and calcification (P <0.001),though no difference in the T2* value was obtained between the peripheral area of hemorrhage and calcification (P>0.05).Conclusions Quantitative measurement of T2* value on GRE T2*WI with a single MRI examination provides a fast,convenient,and effective means in differential diagnosis between intracranial hemorrhage and calcification,which may thus reduce the medical cost and save precious time for clinical management.

  15. Pulsed Rydberg four-wave mixing with motion-induced dephasing in a thermal vapor.

    Science.gov (United States)

    Chen, Yi-Hsin; Ripka, Fabian; Löw, Robert; Pfau, Tilman

    We report on time-resolved pulsed four-wave mixing (FWM) signals in a thermal Rubidium vapor involving a Rydberg state. We observe FWM signals with dephasing times up to 7 ns, strongly dependent on the excitation bandwidth to the Rydberg state. The excitation to the Rydberg state is driven by a pulsed two-photon transition on ns timescales. Combined with a cw de-excitation laser, a strongly directional and collective emission is generated according to a combination of the phase matching effect and averaging over Doppler classes. In contrast to a previous report (Huber et al. in Phys Rev A 90: 053806, 2014) using off-resonant FWM, at a resonant FWM scheme we observe additional revivals of the signal shortly after the incident pulse has ended. We infer that this is a revival of motion-induced constructive interference between the coherent emissions of the thermal atoms. The resonant FWM scheme reveals a richer temporal structure of the signals, compared to similar, but off-resonant excitation schemes. A simple explanation lies in the selectivity of Doppler classes. Our numerical simulations based on a four-level model including a whole Doppler ensemble can qualitatively describe the data.

  16. Influence of pure-dephasing by phonons on exciton-photon interfaces: Quantum microscopic theory

    CERN Document Server

    Kojima, K; Kojima, Kunihiro; Tomita, Akihisa

    2006-01-01

    We have developed a full quantum microscopic theory to analyze the time evolution of transversal and longitudinal components of an exciton-single photon system coupled to bulk acoustic phonons. These components are subjected to two decay processes. One is radiative relaxation and the other is pure-dephasing due to exciton-phonon interaction. The former results in a decay with an exponent linear to time, while the latter causes a faster initial decay than the radiative decay. We analyzed the dependence of the components on the duration of the input one-photon pulse, temperature, and radiative relaxation rates. Such a quantitative analysis is important for the developments of atom-photon interfaces which enable coherent transfer of quantum information between photons and atomic systems. We found that, for a GaAs spherical quantum dot in which the exciton interacts with bulk phonons, the maximal probability of the excited state can be increased up to 75 %. This probability can be considered as the efficiency for...

  17. System-environment correlations for dephasing two-qubit states coupled to thermal baths

    Science.gov (United States)

    Costa, A. C. S.; Beims, M. W.; Strunz, W. T.

    2016-05-01

    Based on the exact dynamics of a two-qubit system and environment, we investigate system-environment (SE) quantum and classical correlations. The coupling is chosen to represent a dephasing channel for one of the qubits and the environment is a proper thermal bath. First we discuss the general issue of dilation for qubit phase damping. Based on the usual thermal bath of harmonic oscillators, we derive criteria of separability and entanglement between an initial X state and the environment. Applying these criteria to initial Werner states, we find that entanglement between the system and environment is built up in time for temperatures below a certain critical temperature Tcrit. On the other hand, the total state remains separable during those short times that are relevant for decoherence and loss of entanglement in the two-qubit state. Close to Tcrit the SE correlations oscillate between separable and entangled. Even though these oscillations are also observed in the entanglement between the two qubits, no simple relation between the loss of entanglement in the two-qubit system and the build-up of entanglement between the system and environment is found.

  18. Effects of defects and dephasing on charge and spin currents in two-dimensional topological insulators

    Science.gov (United States)

    Van Dyke, John S.; Morr, Dirk K.

    2017-01-01

    Using the nonequilibrium Keldysh Green's function formalism, we investigate the effect of defects on the electronic structure and transport properties of two-dimensional topological insulators (TI). We demonstrate how the spatial flow of charge changes between the topologically protected edge and bulk states and show that elastically and inelastically scattering defects that preserve the time-reversal symmetry of the TI lead to qualitatively different effects on the TI's local electronic structure and its transport properties. Moreover, we show that the recently predicted ability to create highly spin-polarized currents by breaking the time-reversal symmetry of the TI via magnetic defects [J. S. Van Dyke and D. K. Morr, Phys. Rev. B 93, 081401 (2016), 10.1103/PhysRevB.93.081401] is robust against the inclusion of a Rashba spin-orbit interaction and the effects of dephasing, and remains unaffected by changes over a wide range of the TI's parameters. We discuss how the sign of the induced spin currents changes under symmetry operations, such as reversal of bias and gate voltages, or spatial reflections. Finally, we show that the insight into the interplay between topology and symmetry of the magnetic defects can be employed for the creation of intriguing quantum phenomena, such as highly localized magnetic fields inside the TI.

  19. Spectral shift and dephasing of electromagnetically induced transparency in an interacting Rydberg gas

    Science.gov (United States)

    Han, Jingshan; Vogt, Thibault; Li, Wenhui

    2016-10-01

    We perform spectroscopic measurements of electromagnetically induced transparency (EIT) in a strongly interacting Rydberg gas. We observe a significant spectral shift and attenuation of the transparency resonance due to the presence of interactions between Rydberg atoms. We characterize the attenuation as the result of an effective dephasing and show that the shift and the dephasing rate increase versus atomic density, probe Rabi frequency, and principal quantum number of Rydberg states. Moreover, we find that the spectral shift is reduced if the size of a Gaussian atomic cloud is increased and that the dephasing rate increases with the EIT pulse duration at large-parameter regimes. We simulate our experiment with a semianalytical model, which yields results in good agreement with our experimental data.

  20. Spin dephasing in a magnetic dipole field around large capillaries: Approximative and exact results

    Science.gov (United States)

    Kurz, F. T.; Buschle, L. R.; Kampf, T.; Zhang, K.; Schlemmer, H. P.; Heiland, S.; Bendszus, M.; Ziener, C. H.

    2016-12-01

    We present an analytical solution of the Bloch-Torrey equation for local spin dephasing in the magnetic dipole field around a capillary and for ensembles of capillaries, and adapt this solution for the study of spin dephasing around large capillaries. In addition, we provide a rigorous mathematical derivation of the slow diffusion approximation for the spin-bearing particles that is used in this regime. We further show that, in analogy to the local magnetization, the transverse magnetization of one MR imaging voxel in the regime of static dephasing (where diffusion effects are not considered) is merely the first term of a series expansion that constitutes the signal in the slow diffusion approximation. Theoretical results are in agreement with experimental data for capillaries in rat muscle at 7 T.

  1. Status of the T2L2/Jason2 Experiment

    Science.gov (United States)

    Exertier, Pierre; Samain, Etienne; Bonnefond, Pascal; Guillemot, Philippe

    2010-12-01

    The T2L2 (Time Transfer by Laser Link) project, developed by CNES and OCA will permit the synchronization of remote ultra stable clocks and the determination of their performances over intercontinental distances. The principle of the experiment derives from Satellite Laser Ranging (SLR) technology with dedicated space equipment. T2L2 was accepted in 2005 to be on board the Jason2 altimetry satellite. The payload consists of both event timer and photo detection modules. The system uses the ultra-stable quartz oscillator of DORIS as on-board reference clock on one hand, and the Laser Reflector Array, making T2L2 a real two-way time transfer system on the other hand. The expected time stability of the T2L2 instrument (detection and timing), referenced by the DORIS oscillator and including all internal error sources should be at the level of 10-12 ps at 1 s and T2L2 should permit to maintain a precision of 1 to a few ps when measuring the phase of a clock during around 1000 seconds. First analysis of T2L2 data permitted to validate some important characteristics of the experiment such as the sensitivity of the instrument to laser pulse amplitude (from single to multi-photon detection mode), data noises (of different sources, SLR and T2L2), and first error budget and time stability of ground to space time transfers. The paper describes the space experiment and highlights the different steps of the data processing after a first year of operations (between July 2008 and June 2009). We show the time stability which can be reached when a laser station is equipped with an Hydrogen Maser or a Cesium clock as a time reference; thus, the first estimations give 7 ps over 30 s. We conclude by presenting the campaigns of ground to ground time transfers already planned between the Paris Observatory and different places in Europe.

  2. Robust Quantum Secure Direct Communication and Deterministic Secure Quantum Communication over Collective Dephasing Noisy Channel

    Institute of Scientific and Technical Information of China (English)

    YUAN Hao; SONG Jun; HE Qin; HAN Lian-Fang; HOU Kui; HU Xiao-Yuan; SHI Shou-Hua

    2008-01-01

    We propose two schemes for quantum secure direct communication (QSDC) and deterministic secure quantum communication (DSQC) over collective dephasing noisy channel.In our schemes,four special two-qubit states are used as the quantum channel.Since these states are unchanged through the collective dephasing noisy channel,the effect of the channel noise can be perfectly overcome.Simultaneously,the security against some usual attacks can be ensured by utilizing the various checking procedures.Furthermore,these two schemes are feasible with present-day technique.

  3. Dissipation, dephasing and quantum Darwinism in qubit systems with random unitary interactions

    Science.gov (United States)

    Balaneskovic, Nenad; Mendler, Marc

    2016-09-01

    We investigate the influence of dissipation and decoherence on quantum Darwinism by generalizing Zurek's original qubit model of decoherence and the establishment of pointer states [W.H. Zurek, Nat. Phys. 5, 181 (2009); see also arXiv: quant-ph/0707.2832v1, pp. 14-19.]. Our model allows for repeated multiple qubit-qubit couplings between system and environment which are described by randomly applied two-qubit quantum operations inducing entanglement, dissipation and dephasing. The resulting stationary qubit states of system and environment are investigated. They exhibit the intricate influence of entanglement generation, dissipation and dephasing on this characteristic quantum phenomenon.

  4. Optical Dephasing in a Glass-like System : A Photon Echo Study of Pentacene in Benzoic Acid

    NARCIS (Netherlands)

    Duppen, Koos; Molenkamp, Laurens W.; Morsink, Jos B.W.; Wiersma, Douwe A.; Trommsdorff, H.P.

    1981-01-01

    Optical absorption and picosecond photon echo experiments are used to study the dephasing of pentacene in benzoic acid. It is shown that, while the absorption spectrum of pentacene is effected by proton transfer in the benzoic acid dimer, the dephasing is caused by elastic and inelastic phonon scatt

  5. T2K near detector tracker

    Energy Technology Data Exchange (ETDEWEB)

    Blaszczyk, Flor de Maria [IRFU/SPP, CEA-Saclay, bat. 141, 91191 Gif-sur-Yvette Cedex (France)

    2010-07-01

    Tokai to Kamioka (T2K) is a new generation neutrino oscillation experiment that started collecting data in 2009 in Japan. A {nu}{mu} beam produced by an intense proton beam colliding onto a target is directed from J-PARC (Tokai) to the 50 kt water Cerenkov detector Super Kamiokande at a distance of 295 km. T2K's main goals are measuring one of the last unknown parameters of the PMNS matrix {Theta}{sub 13} by using {nu}e appearance in the beam, and measuring precisely {Delta}m{sup 2}23 and {Theta}{sub 23} by using {nu}{mu} disappearance. A near detector (ND280) placed in a 0.2 T magnetic field is located at 280 m from the target to allow the characterisation of the neutrino beam before oscillation. In particular, the detector measures the neutrino energy spectra, beam flavor composition, background and cross-sections. ND280 started taking data at the end of 2009. An essential element of ND280 is the tracker, composed of two fine grained detectors (FGD) to serve as targets for neutrino interactions and measure cross-sections, and three time projection chambers (TPC) to track and identify charged particles. The TPCs' readout planes are equipped with Micromegas micro-pattern detectors, achieving a total active surface of 9 m{sup 2}. The first FGD is made of scintillator bars only whereas the second one includes water targets. The performance of the tracker with cosmic ray and neutrino data will be presented. (author)

  6. Many-Body Effect in Spin Dephasing in n-Type GaAs Quantum Wells

    Institute of Scientific and Technical Information of China (English)

    WENG Ming-Qi; WU Ming-Wei

    2005-01-01

    @@ By constructing and numerically solving the kinetic Bloch equations we perform a many-body study of the spin dephasing due to the D'yakonov-Perel' effect in n-type GaAs (100) quantum wells for high temperatures.

  7. Reducing dephasing in coupled quantum dot-cavity systems by engineering the carrier wavefunctions

    DEFF Research Database (Denmark)

    Nysteen, Anders; Nielsen, Per Kær; Mørk, Jesper

    2012-01-01

    We demonstrate theoretically how photon-assisted dephasing by the electron-phonon interaction in a coupled cavity-quantum dot system can be significantly reduced for specific QD-cavity detunings. Our starting point is a recently published theory,1 which considers longitudinal acoustic phonons, de...

  8. T2-prepared velocity selective labelling

    DEFF Research Database (Denmark)

    Alderliesten, Thomas; De Vis, Jill B; Lemmers, Petra M A

    2016-01-01

    2-BIOS correlated with SO2-NIRS (R(2)=0.41, p=0.002) and SvO2-T2-TRIR (R(2)=0.87, p=0.002). In addition, SO2-NIRS correlated with SvO2-T2-TRIR (R(2)=0.85, p=0.003) Frontal cerebral blood flow correlated with SO2-T2-BIOS (R(2)=0.21, p=0.04), but was not significant in relation to SO2-NIRS. DISCUSSION...

  9. Morphological and biochemical T2 evaluation of cartilage repair tissue based on a hybrid double echo at steady state (DESS-T2d) approach.

    Science.gov (United States)

    Welsch, Goetz H; Mamisch, Tallal C; Zak, Lukas; Mauerer, Andreas; Apprich, Sebastian; Stelzeneder, David; Marlovits, Stefan; Trattnig, Siegfried

    2011-10-01

    To use a new approach which provides, based on the widely used three-dimensional double-echo steady-state (DESS) sequence, in addition to the morphological information, the generation of biochemical T2 maps in one hybrid sequence. In 50 consecutive MRIs at 3.0 Tesla (T) after matrix-associated autologous chondrocyte transplantation (MACT) of the knee, by the use this new DESS-T2d approach, the morphological Magnetic resonance Observation of CArtilage Repair Tissue (MOCART) score, as well as biochemical T2d values were assessed. Furthermore, these results were correlated to standard morphological sequences as well as to standard multi-echo spin-echo T2 mapping. The MOCART score correlated (Pearson:0.945; P < 0.001) significantly as assessed with standard morphological sequences (68.8 ± 13.2) and the morphological images of the DESS T2d sequence (68.7 ± 12.6). T2 and T2d relaxation times (ms) were comparable in between the control cartilage (T2: 52.5 ± 11.4; T2d: 46.6 ± 10.3) and the repair tissue (T2: 54.4 ± 11.4; T2d: 47.5 ± 13.0) (T2: P = 0.157; T2d: P = 0.589). As expected, T2d values were lower than the standard-T2 values, however, both functional relaxation times correlated significantly (Pearson:0.429; P < 0.001). The presented hybrid approach provides the possibility to combine morphological and biochemical MRI in one fast 3D sequence, and thus, may attract for the clinical use of biochemical MRI. Copyright © 2011 Wiley-Liss, Inc.

  10. T2VOC user`s guide

    Energy Technology Data Exchange (ETDEWEB)

    Falta, R.W. [Clemson Univ., Clemson, SC (United States). Dept. of Earth Sciences; Pruess, K.; Finsterle, S. [Lawrence Berkeley Lab., CA (United States); Battistelli, A. [AQUATER S.p.A., San Lorenzo in Campo, (Italy)

    1995-03-01

    T2VOC is a numerical simulator for three-phase, three-component, non-isothermal flow of water, air, and a volatile organic compound (VOC) in multidimensional heterogeneous porous media. Developed at the Lawrence Berkeley Laboratory, T2VOC is an extension of the TOUGH2 general-purpose simulation program. This report is a self-contained guide to application of T2VOC to subsurface contamination problems involving nonaqueous phase liquids (NAPLs). It gives a technical description of the T2VOC code, including a discussion of the physical processes modeled, and the mathematical and numerical methods used. Detailed instructions for preparing input data are presented along with several illustrative sample problems.

  11. Comparison of myocardial T1 and T2 values in 3 T with T2* in 1.5 T in patients with iron overload and controls.

    Science.gov (United States)

    Camargo, Gabriel C; Rothstein, Tamara; Junqueira, Flavia P; Fernandes, Elsa; Greiser, Andreas; Strecker, Ralph; Pessoa, Viviani; Lima, Ronaldo S L; Gottlieb, Ilan

    2016-05-01

    Myocardial iron quantification remains limited to 1.5 T systems with T2* measurement. The present study aimed at comparing myocardial T2* values at 1.5 T to T1 and T2 mapping at 3.0 T in patients with iron overload and healthy controls. A total of 17 normal volunteers and seven patients with a history of myocardial iron overload were prospectively enrolled. Mid-interventricular septum T2*, native T1 and T2 times were quantified on the same day, using a multi-echo gradient-echo sequence at 1.5 T and T1 and T2 mapping sequences at 3.0 T, respectively. Subjects with myocardial iron overload (T2* iron overload quantification.

  12. Biochemical (T2, T2* and magnetisation transfer ratio) MRI of knee cartilage: feasibility at ultra-high field (7T) compared with high field (3T) strength

    Energy Technology Data Exchange (ETDEWEB)

    Welsch, Goetz H. [Medical University of Vienna, MR Center, Department of Radiology, Vienna (Austria); University of Erlangen, Department of Trauma Surgery, Erlangen (Germany); Apprich, Sebastian; Zbyn, Stefan; Trattnig, Siegfried [Medical University of Vienna, MR Center, Department of Radiology, Vienna (Austria); Mamisch, Tallal C. [Medical University of Vienna, MR Center, Department of Radiology, Vienna (Austria); University of Berne, Department of Orthopedic Surgery, Berne (Switzerland); Mlynarik, Vladimir [Ecole Polytechnique Federale de Lausanne, Laboratory of Functional and Metabolic imaging, Lausanne (Switzerland); Scheffler, Klaus; Bieri, Oliver [University Hospital Basel, Division of Radiological Physics, Institute of Radiology, Basel (Switzerland)

    2011-06-15

    This study compares the performance and the reproducibility of quantitative T2, T2* and the magnetisation transfer ratio (MTR) of articular cartilage at 7T and 3T. Axial MRI of the patella was performed in 17 knees of healthy volunteers (25.8 {+-} 5.7 years) at 3T and 7T using a comparable surface coil and whole-body MR systems from the same vendor, side-by-side. Thirteen knee joints were assessed once, and four knee joints were measured three times to assess reproducibility. T2 relaxation was prepared by a multi-echo, spin-echo sequence and T2* relaxation by a multi-echo, gradient-echo sequence. MTR was based on a magnetisation transfer-sensitized, steady-state free precession approach. Statistical analysis-of-variance and coefficient-of-variation (CV) were prepared. For T2 and T2*, global values were significantly lower at 7T compared with 3T; the zonal evaluation revealed significantly less pronounced stratification at 7T (p<0.05). MTR provided higher values at 7T (p<0.05). CV, indicating reproducibility, showed slightly lower values at 7T, but only for T2 and T2*. Although lower T2 and T2* relaxation times were expected at 7T, the differences in stratification between the field strengths were reported for the first time. The assessment of MT is feasible at 7T, but requires further investigation. (orig.)

  13. Biochemical (T2, T2* and magnetisation transfer ratio) MRI of knee cartilage: feasibility at ultra-high field (7T) compared with high field (3T) strength.

    Science.gov (United States)

    Welsch, Goetz H; Apprich, Sebastian; Zbyn, Stefan; Mamisch, Tallal C; Mlynarik, Vladimir; Scheffler, Klaus; Bieri, Oliver; Trattnig, Siegfried

    2011-06-01

    This study compares the performance and the reproducibility of quantitative T2, T2* and the magnetisation transfer ratio (MTR) of articular cartilage at 7T and 3T. Axial MRI of the patella was performed in 17 knees of healthy volunteers (25.8 ± 5.7 years) at 3T and 7T using a comparable surface coil and whole-body MR systems from the same vendor, side-by-side. Thirteen knee joints were assessed once, and four knee joints were measured three times to assess reproducibility. T2 relaxation was prepared by a multi-echo, spin-echo sequence and T2* relaxation by a multi-echo, gradient-echo sequence. MTR was based on a magnetisation transfer-sensitized, steady-state free precession approach. Statistical analysis-of-variance and coefficient-of-variation (CV) were prepared. For T2 and T2*, global values were significantly lower at 7T compared with 3T; the zonal evaluation revealed significantly less pronounced stratification at 7T (p < 0.05). MTR provided higher values at 7T (p < 0.05). CV, indicating reproducibility, showed slightly lower values at 7T, but only for T2 and T2*. Although lower T2 and T2* relaxation times were expected at 7T, the differences in stratification between the field strengths were reported for the first time. The assessment of MT is feasible at 7T, but requires further investigation.

  14. T2K neutrino flux prediction

    Science.gov (United States)

    Abe, K.; Abgrall, N.; Aihara, H.; Akiri, T.; Albert, J. B.; Andreopoulos, C.; Aoki, S.; Ariga, A.; Ariga, T.; Assylbekov, S.; Autiero, D.; Barbi, M.; Barker, G. J.; Barr, G.; Bass, M.; Batkiewicz, M.; Bay, F.; Bentham, S. W.; Berardi, V.; Berger, B. E.; Berkman, S.; Bertram, I.; Beznosko, D.; Bhadra, S.; Blaszczyk, F. d. M.; Blondel, A.; Bojechko, C.; Boyd, S.; Bravar, A.; Bronner, C.; Brook-Roberge, D. G.; Buchanan, N.; Calland, R. G.; Caravaca Rodríguez, J.; Cartwright, S. L.; Castillo, R.; Catanesi, M.-G.; Cervera, A.; Cherdack, D.; Christodoulou, G.; Clifton, A.; Coleman, J.; Coleman, S. J.; Collazuol, G.; Connolly, K.; Curioni, A.; Dabrowska, A.; Danko, I.; Das, R.; Davis, S.; Day, M.; de André, J. P. A. M.; de Perio, P.; De Rosa, G.; Dealtry, T.; Densham, C.; Di Lodovico, F.; Di Luise, S.; Dobson, J.; Duboyski, T.; Dufour, F.; Dumarchez, J.; Dytman, S.; Dziewiecki, M.; Dziomba, M.; Emery, S.; Ereditato, A.; Escudero, L.; Esposito, L. S.; Finch, A. J.; Frank, E.; Friend, M.; Fujii, Y.; Fukuda, Y.; Galymov, V.; Gaudin, A.; Giffin, S.; Giganti, C.; Gilje, K.; Golan, T.; Gomez-Cadenas, J. J.; Gonin, M.; Grant, N.; Gudin, D.; Guzowski, P.; Hadley, D. R.; Haesler, A.; Haigh, M. D.; Hansen, D.; Hara, T.; Hartz, M.; Hasegawa, T.; Hastings, N. C.; Hayato, Y.; Hearty, C.; Helmer, R. L.; Hignight, J.; Hillairet, A.; Himmel, A.; Hiraki, T.; Holeczek, J.; Horikawa, S.; Huang, K.; Hyndman, A.; Ichikawa, A. K.; Ieki, K.; Ieva, M.; Ikeda, M.; Imber, J.; Insler, J.; Ishida, T.; Ishii, T.; Ives, S. J.; Iyogi, K.; Izmaylov, A.; Jamieson, B.; Johnson, R. A.; Jo, J. H.; Jonsson, P.; Joo, K. K.; Jover-Manas, G. V.; Jung, C. K.; Kaji, H.; Kajita, T.; Kakuno, H.; Kameda, J.; Kanazawa, Y.; Karlen, D.; Karpikov, I.; Kearns, E.; Khabibullin, M.; Khanam, F.; Khotjantsev, A.; Kielczewska, D.; Kikawa, T.; Kilinski, A.; Kim, J. Y.; Kim, J.; Kim, S. B.; Kirby, B.; Kisiel, J.; Kitching, P.; Kobayashi, T.; Kogan, G.; Konaka, A.; Kormos, L. L.; Korzenev, A.; Koseki, K.; Koshio, Y.; Kowalik, K.; Kreslo, I.; Kropp, W.; Kubo, H.; Kudenko, Y.; Kumaratunga, S.; Kurjata, R.; Kutter, T.; Lagoda, J.; Laihem, K.; Laing, A.; Laveder, M.; Lawe, M.; Lee, K. P.; Licciardi, C.; Lim, I. T.; Lindner, T.; Lister, C.; Litchfield, R. P.; Longhin, A.; Lopez, G. D.; Ludovici, L.; Macaire, M.; Magaletti, L.; Mahn, K.; Malek, M.; Manly, S.; Marchionni, A.; Marino, A. D.; Marteau, J.; Martin, J. F.; Maruyama, T.; Marzec, J.; Masliah, P.; Mathie, E. L.; Matsumura, C.; Matsuoka, K.; Matveev, V.; Mavrokoridis, K.; Mazzucato, E.; McCauley, N.; McFarland, K. S.; McGrew, C.; McLachlan, T.; Messina, M.; Metelko, C.; Mezzetto, M.; Mijakowski, P.; Miller, C. A.; Minamino, A.; Mineev, O.; Mine, S.; Missert, A.; Miura, M.; Monfregola, L.; Moriyama, S.; Mueller, Th. A.; Murakami, A.; Murdoch, M.; Murphy, S.; Myslik, J.; Nagasaki, T.; Nakadaira, T.; Nakahata, M.; Nakai, T.; Nakajima, K.; Nakamura, K.; Nakayama, S.; Nakaya, T.; Nakayoshi, K.; Naples, D.; Nicholls, T. C.; Nielsen, C.; Nishikawa, K.; Nishimura, Y.; O'Keeffe, H. M.; Obayashi, Y.; Ohta, R.; Okumura, K.; Oryszczak, W.; Oser, S. M.; Otani, M.; Owen, R. A.; Oyama, Y.; Pac, M. Y.; Palladino, V.; Paolone, V.; Payne, D.; Pearce, G. F.; Perevozchikov, O.; Perkin, J. D.; Pinzon Guerra, E. S.; Plonski, P.; Poplawska, E.; Popov, B.; Posiadala, M.; Poutissou, J.-M.; Poutissou, R.; Przewlocki, P.; Quilain, B.; Radicioni, E.; Ratoff, P. N.; Ravonel, M.; Rayner, M. A.; Reeves, M.; Reinherz-Aronis, E.; Retiere, F.; Rodrigues, P. A.; Rondio, E.; Rossi, B.; Roth, S.; Rubbia, A.; Ruterbories, D.; Sacco, R.; Sakashita, K.; Sánchez, F.; Scantamburlo, E.; Scholberg, K.; Schwehr, J.; Scott, M.; Scully, D. I.; Seiya, Y.; Sekiguchi, T.; Sekiya, H.; Shibata, M.; Shiozawa, M.; Short, S.; Shustrov, Y.; Sinclair, P.; Smith, B.; Smith, R. J.; Smy, M.; Sobczyk, J. T.; Sobel, H.; Sorel, M.; Southwell, L.; Stamoulis, P.; Steinmann, J.; Still, B.; Sulej, R.; Suzuki, A.; Suzuki, K.; Suzuki, S. Y.; Suzuki, Y.; Szeglowski, T.; Szeptycka, M.; Tacik, R.; Tada, M.; Takahashi, S.; Takeda, A.; Takeuchi, Y.; Tanaka, H. A.; Tanaka, M.; Tanaka, M. M.; Taylor, I. J.; Terhorst, D.; Terri, R.; Thompson, L. F.; Thorley, A.; Tobayama, S.; Toki, W.; Tomura, T.; Totsuka, Y.; Touramanis, C.; Tsukamoto, T.; Tzanov, M.; Uchida, Y.; Ueno, K.; Vacheret, A.; Vagins, M.; Vasseur, G.; Wachala, T.; Waldron, A. V.; Walter, C. W.; Wang, J.; Wark, D.; Wascko, M. O.; Weber, A.; Wendell, R.; Wikström, G.; Wilkes, R. J.; Wilking, M. J.; Wilkinson, C.; Williamson, Z.; Wilson, J. R.; Wilson, R. J.; Wongjirad, T.; Yamada, Y.; Yamamoto, K.; Yanagisawa, C.; Yano, T.; Yen, S.; Yershov, N.; Yokoyama, M.; Yuan, T.; Zalewska, A.; Zambelli, L.; Zaremba, K.; Ziembicki, M.; Zimmerman, E. D.; Zito, M.; Żmuda, J.

    2013-01-01

    The Tokai-to-Kamioka (T2K) experiment studies neutrino oscillations using an off-axis muon neutrino beam with a peak energy of about 0.6 GeV that originates at the Japan Proton Accelerator Research Complex accelerator facility. Interactions of the neutrinos are observed at near detectors placed at 280 m from the production target and at the far detector—Super-Kamiokande—located 295 km away. The flux prediction is an essential part of the successful prediction of neutrino interaction rates at the T2K detectors and is an important input to T2K neutrino oscillation and cross section measurements. A FLUKA and GEANT3-based simulation models the physical processes involved in the neutrino production, from the interaction of primary beam protons in the T2K target, to the decay of hadrons and muons that produce neutrinos. The simulation uses proton beam monitor measurements as inputs. The modeling of hadronic interactions is reweighted using thin target hadron production data, including recent charged pion and kaon measurements from the NA61/SHINE experiment. For the first T2K analyses the uncertainties on the flux prediction are evaluated to be below 15% near the flux peak. The uncertainty on the ratio of the flux predictions at the far and near detectors is less than 2% near the flux peak.

  15. Current status of the T2K experiment

    CERN Document Server

    Oyama, Yuichi

    2011-01-01

    The T2K long-baseline neutrino-oscillationexperiment was started in January 2010 for the purpose of physics data-taking. Until the massive earthquake on March 11, 2011 in Japan, $1.43\\times 10^{20}$ pot data were accumulated. In this data, 6 possible $\

  16. T2K ECAL Test–beam Proposal

    CERN Document Server

    Wark, D; Grant, A; Muir, A; Guzowski, P; Malek, M; Noy, M; Raymond, M; Taylor, I; Uchida, Y; Vacheret, A; Van Schalkwyk, F; Walding, J; Wark, D; Wascko, M; Bertram, I; Chilingarov, A; Davies, G; Finch, A; Hatzikoutelis, A; Kormos, L; Maryon, T; Ratoff, P; Chavez, C; Kellet, L; McCauley, N; Payne, D; Sutcliffe, P; Touramanis, C; Barr, G; Smith, R; West, N; George, M; Hyndman, A; Di Lodovico, F; Owen, R A; Sacco, R; Terri, R; Andreopoulos, C; Durkin, T; Metelko, C; Nicholls, T C; Pearce, G F; Raufer, T M; Rooney, M; Thorpe, M; Weber, A; Woodward, M L; Cartwright, S L; Salih, R; Still, B; Veledar, O; Ward, G; Ward, M; Barker, G J; Carver, A; Litchfield, P; Haigh, M; Whitehead, L; Thompson, L; Touramanis, C

    2008-01-01

    The T2K experiment will search for the last unknown element of the neutrino mixing matrix. An crucial component of the near detector for this experiment is the electromagnetic calorimeter which is being built in the UK. Testbeam time is requested to test the full ECAL system, validate calibration techniques, and determine the hadronic and electromagnetic energy scale of the calorimeter.

  17. Freezing motion-induced dephasing in an atomic-ensemble quantum memory

    CERN Document Server

    Jiang, Yan; Bao, Xiao-Hui; Pan, Jian-Wei

    2016-01-01

    Motion-induced dephasing is a dominant decoherence mechanism for atom-gas quantum memories. In this paper, we develop a new coherent manipulation technique which enables arbitrary engineering of the spin-wave momentum with neglectable noise. By zeroing the spin-wave momentum, motion-induced dephasing can be frozen completely. We experimentally demonstrate this scheme with laser-cooled atoms in a DLCZ configuration. By applying the freezing pulses, memory lifetime gets extended significantly to the limit of atom cloud expansion and does not depend on the detection angle anymore. The observed high cross-correlation above 20 proves that high-fidelity memory operation is well preserved after coherent manipulation.

  18. Left ventricular T2 distribution in Duchenne Muscular Dystrophy

    Directory of Open Access Journals (Sweden)

    Hagenbuch Sean

    2010-03-01

    Full Text Available Abstract Background Although previous studies have helped define the natural history of Duchenne Muscular Dystrophy (DMD-associated cardiomyopathy, the myocardial pathobiology associated with functional impairment in DMD is not yet known. The objective of this study was to assess the distribution of transverse relaxation time (T2 in the left ventricle (LV of DMD patients, and to determine the association of myocardial T2 heterogeneity to the severity of cardiac dysfunction. DMD patients (n = 26 and normal control subjects (n = 13 were studied by Cardiovascular Magnetic Resonance (CMR. DMD subject data was stratified based on subject age and LV Ejection Fraction (EF into the following groups: A (12 years, n = 5. LV mid-slice circumferential myocardial strain (εcc was calculated using tagged CMR imaging. T2 maps of the LV were generated for all subjects using a black blood dual spin echo method at two echo times. The Full Width at Half Maximum (FWHM was calculated from a histogram of LV T2 distribution constructed for each subject. Results In DMD subject groups, FWHM of the T2 histogram rose progressively with age and decreasing EF (Group A FWHM= 25.3 ± 3.8 ms; Group B FWHM= 30.9 ± 5.3 ms; Group C FWHM= 33.0 ± 6.4 ms. Further, FWHM was significantly higher in those with reduced circumferential strain (|εcc| ≤ 12% (Group B, and C than those with |εcc| > 12% (Group A. Group A FWHM was not different from the two normal groups (N1 FWHM = 25.3 ± 3.5 ms; N2 FWHM= 24.0 ± 7.3 ms. Conclusion Reduced EF and εcc correlates well with increased T2 heterogeneity quantified by FWHM, indicating that subclinical functional impairments could be associated with pre-existing abnormalities in tissue structure in young DMD patients.

  19. Quantum corrections to the polarizability and dephasing in isolated disordered metals

    Science.gov (United States)

    Treiber, M.; Ostrovsky, P. M.; Yevtushenko, O. M.; von Delft, J.; Lerner, I. V.

    2013-07-01

    We study the quantum corrections to the polarizability of isolated metallic mesoscopic systems using the loop expansion in diffusive propagators. We show that the difference between connected (grand-canonical ensemble) and isolated (canonical ensemble) systems appears only in subleading terms of the expansion, and can be neglected if the frequency of the external field, ω, is of the order of (or even slightly smaller than) the mean level spacing, Δ. If ω≪Δ, the two-loop correction becomes important. We calculate it by systematically evaluating the ballistic parts (the Hikami boxes) of the corresponding diagrams and exploiting electroneutrality. Our theory allows one to take into account a finite dephasing rate, γ, generated by electron interactions, and it is complementary to the nonperturbative results obtained from a combination of random matrix theory (RMT) and the σ-model, valid at γ→0. Remarkably, we find that the two-loop result for isolated systems with moderately weak dephasing, γ˜Δ, is similar to the result of the RMT+σ-model even in the limit ω→0. For smaller γ, we discuss the possibility to interpolate between the perturbative and the nonperturbative results. We compare our results for the temperature dependence of the polarizability of isolated rings to the experimental data of Deblock [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.84.5379 84, 5379 (2000); Phys. Rev. BPRBMDO1098-012110.1103/PhysRevB.65.075301 65, 075301 (2002)], and we argue that the elusive 0D regime of dephasing might have manifested itself in the observed magneto-oscillations. Besides, we thoroughly discuss possible future measurements of the polarizability, which could aim to reveal the existence of 0D dephasing and the role of the Pauli blocking at small temperatures.

  20. Changes in susceptibility signs on serial T2*-weighted single-shot echo-planar gradient-echo images in acute embolic infarction: comparison with recanalization status on 3D time-of-flight magnetic resonance angiography

    Energy Technology Data Exchange (ETDEWEB)

    Shinohara, Yuki; Kinoshita, Toshibumi; Kinoshita, Fumiko [Research Institute of Brain and Blood Vessels - Akita, Department of Radiology, Akita (Japan)

    2012-05-15

    The present study compares changes in susceptibility signs on follow-up single-shot echo-planar gradient-echo T2*-weighted images (GRE-EPI) with vascular status on follow-up magnetic resonance angiography (MRA) in acute embolic infarction. Twenty consecutive patients with acute embolic infarction repeatedly underwent MR imaging including GRE-EPI and MRA using a 1.5-T MR superconducting system. All patients underwent initial MR examination within 24 h of onset and follow-up MR imaging within 1 month after onset. Changes in susceptibility signs on follow-up GRE-EPI were compatible with vascular status on follow-up MRA in 19 of the 20 patients. Susceptibility signs disappeared with complete recanalization in 13 patients, migrated with partial recanalization in 3, did not change together with the absence of recanalization in 2, and became extended together with the absence of recanalization in 1. Cerebral hemorrhage obscured susceptibility signs in the one remaining patient. Susceptibility signs on follow-up GRE-EPI can reflect changes in an acute embolus, such as recanalization or migration, in this study. Serial GRE-EPI in acute embolism complements the diagnostic certainty of MRA by directly detecting an embolus as a susceptibility sign. (orig.)

  1. Molecular dynamics simulations of proton transverse relaxation times in suspensions of magnetic nanoparticles.

    Science.gov (United States)

    Panczyk, Tomasz; Konczak, Lukasz; Zapotoczny, Szczepan; Szabelski, Pawel; Nowakowska, Maria

    2015-01-01

    In this work we have analyzed the influence of various factors on the transverse relaxation times T2 of water protons in suspension of magnetic nanoparticles. For that purpose we developed a full molecular dynamics force field which includes the effects of dispersion interactions between magnetic nanoparticles and water molecules, electrostatic interactions between charged nanoparticles and magnetic dipole-dipole and dipole-external field interactions. We also accounted for the magnetization reversal within the nanoparticles body frames due to finite magnetic anisotropy barriers. The force field together with the Langevin dynamics imposed on water molecules and the nanoparticles allowed us to monitor the dephasing of water protons in real time. Thus, we were able to determine the T2 relaxation times including the effects of the adsorption of water on the nanoparticles' surfaces, thermal fluctuations of the orientation of nanoparticles' magnetizations as well as the effects of the core-shell architecture of nanoparticles and their agglomeration into clusters. We found that there exists an optimal cluster size for which T2 is minimized and that the retardation of water molecules motion, due to adsorption on the nanoparticles surfaces, has some effect in the measured T2 times. The typical strengths of the external magnetic fields in MRI are enough to keep the magnetizations fixed along the field direction, however, in the case of low magnetic fields, we observed significant enhancement of T2 due to thermal fluctuations of the orientations of magnetizations. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Status of the T2K experiment

    Science.gov (United States)

    Poutissou, J.-M.

    2011-07-01

    These lectures present the status of the Tokai to Kamioka Experiment (T2K) which just started taking data in early 2010. The goals and methodology for the experiment are presented as well as the challenges and prospects for determining the neutrino mixing parameters leading to neutrino oscillation with a particular attention to the determination of the mixing angle θ13.

  3. The T2K Neutrino Flux Prediction

    CERN Document Server

    Abe, K; Aihara, H; Akiri, T; Albert, J B; Andreopoulos, C; Aoki, S; Ariga, A; Ariga, T; Assylbekov, S; Autiero, D; Barbi, M; Barker, G J; Barr, G; Bass, M; Batkiewicz, M; Bay, F; Bentham, S S; Berardi, V; Berger, B E; Berkman, S; Bertram, I; Beznosko, D; Bhadra, S; Blaszczyk, F d M; Blondel, A; Bojechko, C; Boyd, S; Bravar, A; Bronner, C; Brook-Roberge, D G; Buchanan, N; Calland, R G; Rodriguez, J Caravaca; Cartwright, S L; Castillo, R; Catanesi, M G; Cervera, A; Cherdack, D; Christodoulou, G; Clifton, A; Coleman, J; Coleman, S J; Collazuol, G; Connolly, K; Curioni, A; Dabrowska, A; Danko, I; Das, R; Davis, S; Day, M; de Andre, J P A M; de Perio, P; De Rosa, G; Dealtry, T; Densham, C; Di Lodovico, F; Di Luise, S; Dobson, J; Duboyski, T; Dufour, F; Dumarchez, J; Dytman, S; Dziewiecki, M; Dziomba, M; Emery, S; Ereditato, A; Escudero, L; Esposito, L S; Finch, A J; Frank, E; Friend, M; Fujii, Y; Fukuda, Y; Galymov, V; Gaudin, A; Giffin, S; Giganti, C; Gilje, K; Golan, T; Gomez-Cadenas, J J; Gonin, M; Grant, N; Gudin, D; Guzowski, P; Hadley, D R; Haesler, A; Haigh, M D; Hansen, D; Hara, T; Hartz, M; Hasegawa, T; Hastings, N C; Hayato, Y; Hearty, C; Helmer, R L; Hignight, J; Hillairet, A; Himmel, A; Hiraki, T; Holeczek, J; Horikawa, S; Huang, K; Hyndman, A; Ichikawa, A K; Ieki, K; Ieva, M; Ikeda, M; Imber, J; Insler, J; Ishida, T; Ishii, T; Ives, S J; Iyogi, K; Izmaylov, A; Jamieson, B; Johnson, R A; Jo, J H; Jonsson, P; Joo, K K; Jover-Manas, G V; Jung, C K; Kaji, H; Kajita, T; Kakuno, H; Kameda, J; Kanazawa, Y; Karlen, D; Karpikov, I; Kearns, E; Khabibullin, M; Khanam, F; Khotjantsev, A; Kielczewska, D; Kikawa, T; Kilinski, A; Kim, J Y; Kim, J; Kim, S B; Kirby, B; Kisiel, J; Kitching, P; Kobayashi, T; Kogan, G; Konaka, A; Kormos, L L; Korzenev, A; Koseki, K; Koshio, Y; Kowalik, K; Kreslo, I; Kropp, W; Kubo, H; Kudenko, Y; Kumaratunga, S; Kurjata, R; Kutter, T; Lagoda, J; Laihem, K; Laing, A; Laveder, M; Lawe, M; Lee, K P; Licciardi, C; Lim, I T; Lindner, T; Lister, C; Litchfield, R P; Lopez, G D; Ludovici, L; Macaire, M; Magaletti, L; Mahn, K; Malek, M; Manly, S; Marchionni, A; Marino, A D; Marteau, J; Martin, J F; Maruyama, T; Marzec, J; Masliah, P; Mathie, E L; Matsumura, C; Matsuoka, K; Matveev, V; Mavrokoridis, K; Mazzucato, E; McCauley, N; McFarland, K S; McGrew, C; McLachlan, T; Messina, M; Metelko, C; Mezzetto, M; Mijakowski, P; Miller, C A; Minamino, A; Mineev, O; Mine, S; Missert, A; Miura, M; Monfregola, L; Moriyama, S; Mueller, T; Murakami, A; Murdoch, M; Murphy, S; Myslik, J; Nagasaki, T; Nakadaira, T; Nakahata, M; Nakai, T; Nakajima, K; Nakamura, K; Nakayama, S; Nakaya, T; Nakayoshi, K; Naples, D; Nicholls, T C; Nielsen, C; Nishikawa, K; Nishimura, Y; O'Keeffe, H M; Obayashi, Y; Ohta, R; Okumura, K; Oryszczak, W; Oser, S M; Otani, M; Owen, R A; Oyama, Y; Pac, M Y; Palladino, V; Paolone, V; Payne, D; Pearce, G F; Perevozchikov, O; Perkin, J D; Guerra, E S Pinzon; Plonski, P; Poplawska, E; Popov, B; Posiadala, M; Poutissou, J -M; Poutissou, R; Przewlocki, P; Quilain, B; Radicioni, E; Rato, P N; Ravonel, M; Rayner, M A; Reeves, M; Reinherz-Aronis, E; Retiere, F; Rodrigues, P A; Rondio, E; Rossi, B; Roth, S; Rubbia, A; Ruterbories, D; Sacco, R; Sakashita, K; Sanchez, F; Scantamburlo, E; Scholberg, K; Schwehr, J; Scott, M; Scully, D I; Seiya, Y; Sekiguchi, T; Sekiya, H; Shibata, M; Shiozawa, M; Short, S; Shustrov, Y; Sinclair, P; Smith, B; Smith, R J; Smy, M; Sobczyk, J T; Sobel, H; Sorel, M; Stamoulis, P; Steinmann, J; Still, B; Sulej, R; Suzuki, A; Suzuki, K; Suzuki, S Y; Suzuki, Y; Szeglowski, T; Szeptycka, M; Tacik, R; Tada, M; Takahashi, S; Takeda, A; Takeuchi, Y; Tanaka, H A; Tanaka, M; Tanaka, M M; Taylor, I; Terhorst, D; Terri, R; Thompson, L F; Thorley, A; Tobayama, S; Toki, W; Tomura, T; Totsuka, Y; Touramanis, C; Tsukamoto, T; Tzanov, M; Uchida, Y; Ueno, K; Vacheret, A; Vagins, M; Vasseur, G; Wachala, T; Waldron, A V; Walter, C W; Wang, J; Wark, D; Wascko, M O; Weber, A; Wendell, R; Wikstrom, G; Wilkes, R J; Wilking, M J; Wilkinson, C; Williamson, Z; Wilson, J R; Wilson, R J; Wongjirad, T; Yamada, Y; Yamamoto, K; Yanagisawa, C; Yano, T; Yen, S; Yershov, N; Yokoyama, M; Yuan, T; Zalewska, A; Zambelli, L; Zaremba, K; Ziembicki, M; Zimmerman, E D; Zito, M; Zmuda, J

    2012-01-01

    The Tokai-to-Kamioka (T2K) experiment studies neutrino oscillations using an off-axis muon neutrino beam with a peak energy of about 0.6 GeV that originates at the J-PARC accelerator facility. Interactions of the neutrinos are observed at near detectors placed at 280 m from the production target and at the far detector -- Super-Kamiokande (SK) -- located 295 km away. The flux prediction is an essential part of the successful prediction of neutrino interaction rates at the T2K detectors and is an important input to T2K neutrino oscillation and cross section measurements. A FLUKA and GEANT3 based simulation models the physical processes involved in the neutrino production, from the interaction of primary beam protons in the T2K target, to the decay of hadrons and muons that produce neutrinos. The simulation uses proton beam monitor measurements as inputs. The modeling of hadronic interactions is re-weighted using thin target hadron production data, including recent charged pion and kaon measurements from the NA...

  4. Longitudinal analysis of MRI T(2) knee cartilage laminar organization in a subset of patients from the osteoarthritis initiative.

    Science.gov (United States)

    Carballido-Gamio, Julio; Blumenkrantz, Gabrielle; Lynch, John A; Link, Thomas M; Majumdar, Sharmila

    2010-02-01

    The purpose of this pilot study was to longitudinally quantify the T(2) laminar integrity of knee cartilage in a subset of subjects with osteoarthritis from the Osteoarthritis Initiative at baseline, 1-year follow-up, and 2-year follow-up. Cartilage from 13 subjects was divided into six compartments and subdivided into deep and superficial layers. At each time point, mean T(2) values in superficial and deep layers were compared. Longitudinal analysis included full-thickness mean T(2), mean deep T(2), mean superficial T(2), mean T(2) laminar difference, mean percentage T(2) laminar difference, and two-dimensional measures of cartilage thickness. More compartments showed significantly higher superficial T(2) than deep T(2) values at baseline and 1-year follow-up compared to 2-year follow-up. No significant longitudinal changes of full-thickness mean T(2) and superficial T(2) values were observed. Significant longitudinal changes were observed in the deep T(2) values, T(2) laminar difference, and percentage T(2) laminar difference. Cartilage thickness had no influence on T(2) analysis. Results of this study suggest that laminar analysis may improve the sensitivity to detect longitudinal T(2) changes and that disruption of the T(2) laminar organization of knee cartilage may be present in knee osteoarthritis progressors. Further investigation is warranted to evaluate the potential of the presented methodology to better characterize evolution and pathophysiology of osteoarthritis.

  5. T2* mapping of articular cartilage: current status of research and first clinical applications.

    Science.gov (United States)

    Andreisek, Gustav; Weiger, Markus

    2014-01-01

    T2* mapping is a relatively new method for the compositional assessment of the articular cartilage. Typically, a multigradient echo or an ultrashort echo time imaging technique with a range of short and very short echo times is used. In most studies, imaging is performed at a high field strength, that is, 3 and 7 T. Postprocessing includes exponential fitting of relaxation decay and manual region-of-interest-based measurements of T2* times on T2* maps. Detailed analyses of T2* times of articular cartilage have shown distinct T2* components with shorter and longer T2* times. Moreover, there is a zonal distribution with a significant depthwise gradient of T2*, with relatively short times near the osteochondral junction and relatively long times at the cartilage's surface. T2* times of normal articular cartilage at the knee are, when averaged over the whole cartilage thickness and using monoexponential fitting, approximately 20 milliseconds. The results of recent studies have shown a good test-retest as well as interreader and intrareader reliabilities for T2* mapping. This article provides a descriptive review of the current literature, briefly discusses the technique itself, and provides an outlook on future research questions and possible clinical applications.

  6. ESR study of atomic hydrogen and tritium in solid T$_{2}$ and T$_{2}$:H$_{2}$ matrices below 1K

    CERN Document Server

    Sheludiakov, S; Järvinen, J; Vainio, O; Lehtonen, L; Zvezdov, D; Vasiliev, S; Lee, D M; Khmelenko, V V

    2016-01-01

    We report on the first ESR study of atomic hydrogen and tritium stabilized in a solid T$_{2}$ and T$_{2}$:H$_{2}$ matrices down to 70$\\,$mK. The concentrations of T atoms in pure T$_{2}$ approached $2\\times10^{20}$cm$^{-3}$ and record-high concentrations of H atoms $\\sim1\\times10^{20}$cm$^{-3}$ were reached in T$_{2}$:H$_{2}$ solid mixtures where a fraction of T atoms became converted into H due to the isotopic exchange reaction T+H$_2\\rightarrow$TH+H. The maximum concentrations of unpaired T and H atoms was limited by their recombination which becomes enforced by efficient atomic diffusion due to a presence of a large number of vacancies and phonons generated in the matrices by $\\beta$-particles. Recombination also appeared in an explosive manner both being stimulated and spontaneously in thick films where sample cooling was insufficient. We suggest that the main mechanism for H and T migration is physical diffusion related to tunneling or hopping to vacant sites in contrast to isotopic chemical reactions wh...

  7. Quantitative analysis of disc degeneration using axial T2 mapping in a percutaneous annular puncture model in rabbits

    Energy Technology Data Exchange (ETDEWEB)

    Chai, Jee Won; Kim, Su Jin [Dept. of Radiology, SMG-SNU Boramae Medical Center, Seoul (Korea, Republic of); Kang, Heung Sik; Lee, Joon Woo [Dept. of Radiology, Seoul National University Bundang Hospital, Seongnam (Korea, Republic of); Hong, Sung Hwan [Dept. of Radiology, Seoul National University Hospital, Seoul (Korea, Republic of)

    2016-02-15

    To evaluate T2 relaxation time change using axial T2 mapping in a rabbit degenerated disc model and determine the most correlated variable with histologic score among T2 relaxation time, disc height index, and Pfirrmann grade. Degenerated disc model was made in 4 lumbar discs of 11 rabbits (n = 44) by percutaneous annular puncture with various severities of an injury. Lumbar spine lateral radiograph, MR T2 sagittal scan and MR axial T2 mapping were obtained at baseline and 2 weeks and 4 weeks after the injury in 7 rabbits and at baseline and 2 weeks, 4 weeks, and 6 weeks after the injury in 4 rabbits. Generalized estimating equations were used for a longitudinal analysis of changes in T2 relaxation time in degenerated disc model. T2 relaxation time, disc height index and Pfirrmann grade were correlated with the histologic scoring of disc degeneration using Spearman's rho test. There was a significant difference in T2 relaxation time between uninjured and injured discs after annular puncture. Progressive decrease in T2 relaxation time was observed in injured discs throughout the study period. Lower T2 relaxation time was observed in the more severely injured discs. T2 relaxation time showed the strongest inverse correlation with the histologic score among the variables investigated (r = -0.811, p < 0.001). T2 relaxation time measured with axial T2 mapping in degenerated discs is a potential method to assess disc degeneration.

  8. Wettability of Chalk and Argillaceous Sandstones Assessed from T1/T2 Ratio

    DEFF Research Database (Denmark)

    Katika, Konstantina; Saidian, M.; Fabricius, Ida Lykke

    to mineral properties. Thus, longitudinal, T1, and transverse, T2, relaxation times should in principle be similar. However, microscopic magnetic gradients related to minerals can shorten T2 as compared to T1 provided the saturating fluid has high affinity to the solid. We consequently find that the T1/T2...... with water, oil or oil/water at irreducible water saturation. The T1/T2 ratio obtained from T1-T2 maps reflects the T2-shortening. We compare the T1/T2 ratio for the same type of rock, saturated with different fluids. The chalk shows high affinity for water, Berea sandstone has no clear preference for oil...

  9. T2K Results and Future Plans

    CERN Document Server

    Di Lodovico, Francesca

    2011-01-01

    We present the numu to nue appearance and the numu disappearance results, using a total of 1.43 x 10^{20} protons on target collected with the T2K experiment. T2K is long baseline neutrino experiment in Japan with detectors located at J-PARC, Tokai, and at Kamioka in the Gifu Prefecture, situated 295 km away from J-PARC. The muon neutrino beam is produced and measured at the near detectors at J-PARC whilst the neutrino rates after oscillation are measured with the Super-Kamiokande detector, at Kamioka. A total of six events pass all the selection criteria for numu to nue oscillations at the far detector Super-Kamiokande, leading to 0.03(0.04) 0.84 and 2.1 x 10^{-3} < Delta m^2_{23} (eV^2) < 3.1 x 10^{-3}. Finally, we present an overview of the T2K plans from 2011 onwards.

  10. Zeno and anti-Zeno effects for photon polarization dephasing

    CERN Document Server

    Kofman, A G; Opatrny, T

    2001-01-01

    We discuss a simple, experimentally feasible scheme, which elucidates the principles of controlling ("engineering") the reservoir spectrum and the spectral broadening incurred by repeated measurements. This control can yield either the inhibition (Zeno effect) or the acceleration (anti-Zeno effect) of the quasi-exponential decay of the observed state by means of frequent measurements. In the discussed scheme, a photon is bouncing back and forth between two perfect mirrors, each time passing a polarization rotator. The horizontal and vertical polarizations can be viewed as analogs of an excited and a ground state of a two level system (TLS). A polarization beam splitter and an absorber for the vertically polarized photon are inserted between the mirrors, and effect measurements of the polarization. The polarization angle acquired in the electrooptic polarization rotator can fluctuate randomly, e.g., via noisy modulation. In the absence of an absorber the polarization randomization corresponds to TLS decay into...

  11. Pediatric cervical spine marrow T2 hyperintensity: a systematic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gefen, Ron [Cooper University Hospital, Department of Diagnostic Radiology, Candem, NJ (United States); Schweitzer, Mark E. [The Ottawa Hospital and University of Ottawa, Department of Diagnostic Imaging, Ottawa (Canada); Shabshin, Nogah [Department of Diagnostic Imaging, Chaim Sheba Medical Center, Tel-HaShomer (Israel); Hospital of University of Pennsylvania, Department of Diagnostic Imaging, Philadelphia, PA (United States)

    2011-08-15

    Hyperintense areas of vertebral bone marrow on fluid-sensitive sequences are at times seen on pediatric MRI of the cervical spine in children without suspicious clinical conditions to explain marrow pathology. Although these likely have no clinical significance they may be mistaken for pathology. The purpose of this study is to systematically evaluate the locations and patterns of marrow T2 hyperintensity in the pediatric cervical spine, with respect to age. At 1.5 T, the C2 through T3 vertebrae of 82 children aged 0-17 years without clinically suspicious marrow abnormality were retrospectively reviewed by two musculoskeletal radiologists, who were blinded to patients' age. The frequency, intensity, and location of the foci of marrow T2 hyperintensity were recorded for each vertebra on a 12-point scoring system and were correlated with the patients' age. Foci of marrow hyperintensity were seen in 46/82 (56.1%) patients and in 241/734 (32.8%) vertebrae. Foci were most common in C4 (42% of patients), C5 (45.7%), and C6 (37.8%). The foci of T2 hyperintensity were more common inferiorly (188 foci) and adjacent to the anterior cortex (123). Analysis revealed no significant correlation between age and marrow score (Spearman = -0.147, P = 0.19), but did find a trend towards increased presence of marrow T2 hyperintensity in the ages of most rapid growth, 8-14 years (81.5% of patients). Vertebral body marrow T2 hyperintensity was most common endosteally and in the mid-cervical spine with a slight peak in adolescence. We therefore believe that these pediatric cervical marrow changes may be related to rapid bone growth at the point of maximal kyphotic stress. (orig.)

  12. Development of Vaccines to the Mycotoxin T-2

    Science.gov (United States)

    2007-11-02

    allogeneic system. Standardization of Leucopenia in Mice: To examine the efficacy of the anti-idiotypic antibody as a prophylactic agent, in vivo...mice and rats served as controls. Leucopenia was monitored periodically at different time intervals. No dramatlc difference (Fig. 3) in the onset of... leucopenia and its reversal to normal levels was observed in immune animals. These experiments need to be repeated using higher levels of T-2 toxin

  13. Revisiting T2KK and T2KO physics potential and $\

    CERN Document Server

    Hagiwara, Kaoru; Okamura, Naotoshi; Takaesu, Yoshitaro

    2016-01-01

    We revisit the sensitivity study of the Tokai-to-Kamioka-and-Korea (T2KK) and Tokai-to-Kamioka-and-Oki (T2KO) proposals where a water Cerenkov detector with the 100 kton fiducial volume is placed in Korea ($L = 1000$ km) and Oki island ($L = 653$ km) in Japan, respectively, in addition to the Super-Kamiokande for determination of the neutrino mass hierarchy and leptonic CP phase ($\\delta_{CP}$). We systematically study the running ratio of the $\

  14. Quantitative T2, T2*, and T2' MR imaging in patients with ischemic leukoaraiosis might detect microstructural changes and cortical hypoxia

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Marlies; Helfrich, Michael; Magerkurth, Joerg; Blasel, Stella; Porto, Luciana; Jurcoane, Alina; Hattingen, Elke [University Hospital, Goethe-University, Institute of Neuroradiology, Frankfurt am Main, Frankfurt (Germany); Volz, Steffen; Deichmann, Ralf [University Hospital, Goethe-University, Brain Imaging Center, Frankfurt (Germany); Singer, Oliver C. [University Hospital, Goethe-University, Department of Neurology, Frankfurt (Germany)

    2015-10-15

    Quantitative MRI with T2, T2*, and T2' mapping has been shown to non-invasively depict microstructural changes (T2) and oxygenation status (T2* and T2') that are invisible on conventional MRI. Therefore, we aimed to assess whether T2 and T2' quantification detects cerebral (micro-)structural damage and chronic hypoxia in lesions and in normal appearing white matter (WM) and gray matter (GM) of patients with ischemic leukoaraiosis (IL). Measurements were complemented by the assessment of the cerebral blood flow (CBF) and the degree of GM and WM atrophy. Eighteen patients with IL and 18 age-matched healthy controls were included. High-resolution, motion-corrected T2, T2*, and T2' mapping, CBF mapping (pulsed arterial spin labeling, PASL), and segmentation of GM and WM were used to depict specific changes in both groups. All parameters were compared between patients and healthy controls, using t testing. Values of p < 0.05 were accepted as statistically significant. Patients showed significantly increased T2 in lesions (p < 0.01) and in unaffected WM (p = 0.045) as well as significantly increased T2* in lesions (p = 0.003). A significant decrease of T2' was detected in patients in unaffected WM (p = 0.027), while no T2' changes were observed in GM (p = 0.13). Both unaffected WM and GM were significantly decreased in volume in the patient-group (p < 0.01). No differences of PASL-based CBF could be shown. Non-invasive quantitative MRI with T2, T2*, and T2' mapping might be used to detect subtle structural and metabolic changes in IL. Assessing the grade of microstructural damage and hypoxia might be helpful to monitor disease progression and to perform risk assessment. (orig.)

  15. Latest oscillation results from T2K

    CERN Document Server

    Khabibullin, Marat

    2011-01-01

    The latest oscillation results obtained in the off-axis accelerator neutrino experiment T2K are presented. In the data sample, corresponding to 1.43 x 10^20 protons on target, 6 electron neutrino candidate events pass the selection criteria, while the expected number of background events for sin^2 2\\theta_{13}=0 is 1.5 \\pm 0.3 (syst.). The probability to observe six or more candidate events due to background is 0.7%, equivalent to 2.5-sigma significance. In the muon neutrino disappearance analysis the obtained atmospheric oscillation parameters are consistent with results from the Super-Kamiokande and MINOS experiments.

  16. Morphological imaging and T2 and T2* mapping of hip cartilage at 7 Tesla MRI under the influence of intravenous gadolinium

    Energy Technology Data Exchange (ETDEWEB)

    Lazik-Palm, Andrea; Geis, Christina; Goebel, Juliane; Theysohn, Jens M. [University Hospital Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Kraff, Oliver; Johst, Soeren [University of Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); Ladd, Mark E. [University Hospital Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); University of Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); German Cancer Research Center (DKFZ), Division of Medical Physics in Radiology, Heidelberg (Germany); Quick, Harald H. [University of Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); University Hospital Essen, High-Field and Hybrid MR Imaging, Essen (Germany)

    2016-11-15

    To investigate the influence of intravenous gadolinium on cartilage T2 and T2* relaxation times and on morphological image quality at 7-T hip MRI. Hips of 11 healthy volunteers were examined at 7 T. Multi-echo sequences for T2 and T2* mapping, 3D T1 volumetric interpolated breath-hold examination (VIBE) and double-echo steady-state (DESS) sequences were acquired before and after intravenous application of gadolinium according to a delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) protocol. Cartilage relaxation times were measured in both scans. Morphological sequences were assessed quantitatively using contrast ratios and qualitatively using a 4-point Likert scale. Student's t-test, Pearson's correlation (ρ) and Wilcoxon sign-rank test were used for statistical comparisons. Pre- and post-contrast T2 and T2* values were highly correlated (T2: acetabular: ρ = 0.76, femoral: ρ = 0.77; T2*: acetabular: ρ = 0.80, femoral: ρ = 0.72). Gadolinium enhanced contrasts between cartilage and joint fluid in DESS and T1 VIBE according to the qualitative (p = 0.01) and quantitative (p < 0.001) analysis. The delineation of acetabular and femoral cartilage and the labrum predominantly improved with gadolinium. Gadolinium showed no relevant influence on T2 or T2* relaxation times and improved morphological image quality at 7 T. Therefore, morphological and quantitative sequences including dGEMRIC can be conducted in a one-stop-shop examination. (orig.)

  17. Threshold for strong thermal dephasing in periodically poled KTP in external cavity frequency doubling

    DEFF Research Database (Denmark)

    Lundeman, Jesper Holm; Jensen, Ole Bjarlin; Andersen, Peter E.;

    2009-01-01

    We present a measurement series of the efficiency of periodically poled KTP used for second-harmonic generation in an external phase-locked cavity. Due to the high absorption (0.01 cm^−1) in the PPKTP crystal at the pump wavelength a strong thermal dephasing of the periodically poled grating...... is observed for high pump powers. For four different resonator setups, it was experimentally found that a threshold parameter could be defined as the ratio between the focal intensity in the crystal and the single-pass conversion efficiency. The value of this threshold for the onset of strong thermal...... dephasing was found to be 1.41×10^10 W^2 m^-2 in our 30-mm long PPKTP sample. This threshold parameter marks the onset of thermally induced instability that leads to a degradation of the SHG conversion efficiency. Above the threshold the shape of the resonance peaks of the resonator changed from symmetrical...

  18. The role of chaos in quantum communication through a dynamical dephasing channel

    CERN Document Server

    Lemos, Gabriela Barreto

    2010-01-01

    In this article we treat the subject of chaotic environments with few degrees of freedom in quantum communication by investigating a conservative dynamical map as a model of a dephasing quantum channel. When the channel's dynamics is chaotic, we investigate the model's semi-classical limit and show that the entropy exchange grows at a constant rate which depends on a single parameter (the interaction strength), analogous to stochastic models of dephasing channels. We analyze memory effects in the channel and present strong physical arguments to support that the present model is forgetful in the chaotic regime while memory effects in general cannot be ignored when channel dynamics is regular. In order to render the non-chaotic channel forgetful, it becomes necessary to apply a reset to the channel and this reset can efficiently be modeled by application of a chaotic map. We may then refer to encoding theorems (valid in the case of forgetful channels) to present evidence of a transition from noiseless to noisy ...

  19. Role of chaos in quantum communication through a dynamical dephasing channel

    Science.gov (United States)

    Lemos, Gabriela Barreto; Benenti, Giuliano

    2010-06-01

    In this article we treat the subject of chaotic environments with few degrees of freedom in quantum communication by investigating a conservative dynamical map as a model of a dephasing quantum channel. When the channel’s dynamics is chaotic, we investigate the model’s semi-classical limit and show that the entropy exchange grows at a constant rate which depends on a single parameter (the interaction strength), analogous to stochastic models of dephasing channels. We analyze memory effects in the channel and present strong physical arguments to support that the present model is forgetful in the chaotic regime while memory effects in general cannot be ignored when channel dynamics is regular. In order to render the nonchaotic channel forgetful, it becomes necessary to apply a reset to the channel and this reset can efficiently be modeled by application of a chaotic map. We may then refer to encoding theorems (valid in the case of forgetful channels) to present evidence of a transition from noiseless to noisy channel due to the environment’s transition from regular to chaotic dynamics.

  20. Biomechanical Analysis of T2 Exercise

    Science.gov (United States)

    DeWitt, John K.; Ploutz-Snyder, Lori; Everett, Meghan; Newby, Nathaniel; Scott-Pandorf, Melissa; Guilliams, Mark E.

    2010-01-01

    Crewmembers regularly perform treadmill exercise on the ISS. With the implementation of T2 on ISS, there is now the capacity to obtain ground reaction force (GRF) data GRF data combined with video motion data allows biomechanical analyses to occur that generate joint torque estimates from exercise conditions. Knowledge of how speed and load influence joint torque will provide quantitative information on which exercise prescriptions can be based. The objective is to determine the joint kinematics, ground reaction forces, and joint kinetics associated with treadmill exercise on the ISS. This study will: 1) Determine if specific exercise speed and harness load combinations are superior to others in exercise benefit; and 2) Aid in the design of exercise prescriptions that will be most beneficial in maintaining crewmember health.

  1. Toeplitz Operators on H2(T2)%H2(T2)上的Toeplitz算子

    Institute of Scientific and Technical Information of China (English)

    杨立敏

    2001-01-01

    给出了H2(T2)上Toeplitz算子的特征方程:T*zTTz=T,T*wTTw=T,及两个Toeplitz算子ψ,ψ∈L∞(T2),Tψ和Tφ的乘积TψTφ仍为Toeplitz算子的充要条件是:ψ对z、w中零个、一个或两个变量共轭解析,φ对余下变量解析,且乘积为Tψφ.

  2. Ex vivo T2 relaxation: associations with age-related neuropathology and cognition.

    Science.gov (United States)

    Dawe, Robert J; Bennett, David A; Schneider, Julie A; Leurgans, Sue E; Kotrotsou, Aikaterini; Boyle, Patricia A; Arfanakis, Konstantinos

    2014-07-01

    The transverse relaxation time constant, T(2), is sensitive to brain tissue's free water content and the presence of paramagnetic materials such as iron. In this study, ex vivo magnetic resonance imaging was used to investigate alterations in T(2) related to Alzheimer's disease (AD) pathology and other types of neuropathology common in old age, as well as the relationship between T(2) alterations and cognition. Cerebral hemispheres were obtained from 371 deceased older adults. Using fast spin-echo imaging with multiple echo times, T(2) maps were produced and warped to a study-specific template. Hemispheres underwent neuropathologic examination for identification of AD pathology and other common age-related neuropathologies. Voxelwise linear regression was carried out to detect regions of pathology-related T(2) alterations and, in separate analyses, regions in which T(2) alterations were linked to antemortem cognitive performance. AD pathology was associated with T(2) prolongation in white matter of all lobes and T(2) shortening in the basal ganglia and insula. Gross infarcts were associated with T(2) prolongation in white matter of all lobes, and in the thalamus and basal ganglia. Hippocampal sclerosis was associated with T(2) prolongation in the hippocampus and white matter of the temporal lobe. After controlling for neuropathology, T(2) prolongation in the frontal lobe white matter was associated with lower performance in the episodic, semantic, and working memory domains. In addition, voxelwise analysis of in vivo and ex vivo T(2) values indicated a positive relationship between the two, though further investigation is necessary to accurately translate findings of the present study to the in vivo case.

  3. Interaction and dephasing of center-of-mass quantized excitons in wide ZnSe/Zn0.94Mg0.06Se quantum wells

    DEFF Research Database (Denmark)

    Wagner, Hans Peter; Schätz, A.; Maier, R.

    1998-01-01

    We investigate the interaction and dephasing of the excitons in wide ZnSe/Zn0.94Mg0.06Se quantum wells by spectrally resolved, femtosecond four-wave mixing (FWM). Polarization-dependent measurements indicate that excitation-induced dephasing is the dominant FWM process. The biexcitons of the center...

  4. Smallest bitter taste receptor(T2Rs)gene repertoire in carnivores%Smallest bitter taste receptor (T2Rs) gene repertoire in carnivores

    Institute of Scientific and Technical Information of China (English)

    Ling-Ling HU; Peng SHI

    2013-01-01

    Bitter taste reception is presumably associated with dietary selection,preventing animals from ingesting potentially harmful compounds.Accordingly,carnivores,who encounter these toxic substances less often,should have fewer genes associated with bitter taste reception compared with herbivores and omnivores.To investigate the genetic basis of bitter taste reception,we confirmed bitter taste receptor (T2R) genes previously found in the genome sequences of two herbivores (cow and horse),two omnivores (mouse and rat) and one carnivore (dog).We also identified,for the first time,the T2R repertoire from the genome of other four carnivore species (ferret,giant panda,polar bear and cat) and detected 17-20 bitter receptor genes from the five carnivore genomes,including 12-16 intact genes,0-1 partial but putatively functional genes,and 3-8 pseudogenes.Both the intact T2R genes and the total T2R gene number among carnivores were the smallest among the tested species,supporting earlier speculations that carnivores have fewer T2R genes,herbivores an intermediate number,and omnivores the largest T2R gene repertoire.To further explain the genetic basis for this disparity,we constructed a phylogenetic tree,which showed most of the T2R genes from the five carnivores were one-to-one orthologs across the tree,suggesting that carnivore T2Rs were conserved among mammals.Similarly,the small carnivore T2R family size was likely due to rare duplication events.Collectively,these results strengthen arguments for the connection between T2R gene family size,diet and habit.

  5. Parametric T2 and T2* mapping techniques to visualize intervertebral disc degeneration in patients with low back pain: initial results on the clinical use of 3.0 Tesla MRI

    Energy Technology Data Exchange (ETDEWEB)

    Welsch, Goetz Hannes [Medical University of Vienna, MR Center - High Field MR, Department of Radiology, Vienna (Austria); University of Erlangen, Department of Trauma Surgery, Erlangen (Germany); Trattnig, Siegfried; Goed, Sabine; Stelzeneder, David [Medical University of Vienna, MR Center - High Field MR, Department of Radiology, Vienna (Austria); Paternostro-Sluga, Tatjana [Medical University of Vienna, Department of Physical Therapy, Vienna (Austria); Bohndorf, Klaus [Klinikum Augsburg, Department of Radiology, Augsburg (Germany); Mamisch, Tallal Charles [Medical University of Vienna, MR Center - High Field MR, Department of Radiology, Vienna (Austria); University of Berne, Department of Orthopedic Surgery, Berne (Switzerland)

    2011-05-15

    To assess, compare and correlate quantitative T2 and T2* relaxation time measurements of intervertebral discs (IVDs) in patients suffering from low back pain, with respect to the IVD degeneration as assessed by the morphological Pfirrmann Score. Special focus was on the spatial variation of T2 and T2* between the annulus fibrosus (AF) and the nucleus pulposus (NP). Thirty patients (mean age: 38.1 {+-} 9.1 years; 20 female, 10 male) suffering from low back pain were included. Morphological (sagittal T1-FSE, sagittal and axial T2-FSE) and biochemical (sagittal T2- and T2* mapping) MRI was performed at 3 Tesla covering IVDs L1-L2 to L5-S1. All IVDs were morphologically classified using the Pfirrmann score. Region-of-interest (ROI) analysis was performed on midsagittal T2 and T2* maps at five ROIs from anterior to posterior to obtain information on spatial variation between the AF and the NP. Statistical analysis-of-variance and Pearson correlation was performed. The spatial variation as an increase in T2 and T2* values from the AF to the NP was highest at Pfirmann grade I and declined at higher Pfirmann grades II-IV (p < 0.05). With increased IVD degeneration, T2 and T2* revealed a clear differences in the NP, whereas T2* was additionally able to depict changes in the posterior AF. Correlation between T2 and T2* showed a medium Pearson's correlation (0.210 to 0.356 [p < 0.001]). The clear differentiation of IVD degeneration and the possible quantification by means of T2 and fast T2* mapping may provide a new tool for follow-up therapy protocols in patients with low back pain. (orig.)

  6. Design of practical T2-selective RF excitation (TELEX) pulses.

    Science.gov (United States)

    Sussman, M S; Pauly, J M; Wright, G A

    1998-12-01

    Traditional T2-based imaging techniques are geared toward imaging long-T2 species. Traditional techniques are, therefore, not optimal in clinical situations where the information of interest lies in the short-T2 species. T2-selective RF excitation (TELEX) is a technique for obtaining a T2-based contrast that highlights short-T2 values while suppressing long-T2 values-opposite to traditional T2 contrast. Previously, TELEX has been demonstrated qualitatively to highlight only very short-T2 values (T2 approximately 0.001 s). When applied to longer T2 values (T2 > or = 0.01 s), TELEX becomes sensitive to deltaB0 non-uniformities. This restricts its application to problems in which the T2 of interest is very short. In this study, TELEX is characterized quantitatively. Furthermore, a bandwidth broadening scheme is developed that reduces the deltaB0 sensitivity of TELEX. This permits the technique to be applied to longer T2 values. The capabilities and limitations of a practical implementation of TELEX are discussed.

  7. The correlation of hippocampal T2-mapping with neuropsychology test in patients with Alzheimer's disease.

    Directory of Open Access Journals (Sweden)

    Zhuren Luo

    Full Text Available OBJECTIVES: 1 To deduce T2, the inverse of the transverse relaxation rate (R2, in the hippocampus of healthy adults; 2 to investigate the brain iron deposition in Alzheimer's disease (AD patients and age-matched healthy controls using T2-values. METHODS: T2-weighted data from the bilateral-hippocampi of ten AD patients and sixty healthy controls were collected at six echo time points using multi-slice multi-echo turbo spin echo (MSME-TSE imaging on a 3.0 T MR-scanner, followed by the neuropsychological testing. The correlations between T2-values and Mini-Mental State Examination (MMSE scores were investigated on group-wise basis (covariates in the group-wise analyses: gender, age, side and healthy/AD. RESULTS: There were no significant differences in hippocampal T2-values on intra-gender and inter-gender basis (P > 0.05. Hippocampal T2-values of both sides were similar (right: 85.2±2.4 milliseconds; left: 85.3±2.5 milliseconds. The bilateral hippocampal T2 values correlated moderately with age (right: r = -0.59; left: -0.58; P < 0.001. The AD-group had significantly lower T2-values in the hippocampus when compared to normal controls (P < 0.001 and such low T2-values had a strong positive correlation with the MMSE score (R (2 = 0.97; P < 0.05. CONCLUSION: Patients with AD showed significantly lower T2 values, which can be attributed to the increased iron depositions in the hippocampus. A positive correlation between T2-values and cognition scores suggests that quantitative T2 can be used in the early diagnosis of AD and in the monitoring of the treatment response.

  8. Analysis of T-2 Toxin Removal Factors in a Lactococcus Fermentation System.

    Science.gov (United States)

    Zhou, Lang-Hua; Wang, Ya-Ling; Qiu, Mei; Shi, Qi; Sun, Li-Jun; Liao, Jian-Meng; Xu, De-Feng; Liu, Ying; Fang, Zhi-Jia; Gooneratne, Ravi

    2017-09-01

    The objective of this work was to determine the bacterial strains and factors that most efficiently degrade T-2 toxin in foods or animal feed. To determine the most efficient strain and optimal incubation times for degradation of T-2, the rate of T-2 removal by three lactic acid bacteria strains was quantified by liquid chromatography plus tandem mass spectrometry after incubation in de Man Rogosa Sharpe broth with 50 ng mL(-1) T-2 at 37°C for 96 h. Various components of the most efficient degradation strain fermentation systems were extracted, and the ability to remove T-2 was assayed. Lactococcus lactis CAMT22361 was the most efficient degradation strain for removing T-2. Yeast extract powder interfered with L. lactis CAMT22361 in the degradation process. T-2 toxin was removed by various components of the L. lactis CAMT22361 cells in the following order: nonprotein material of the extracellular fraction > protein in the extracellular fraction > whole cell ≈ cell wall > cell intracellular matrix fluid. T-2 removal rates were 54.08% ± 0.79%, 43.65% ± 0.84%, 43.09% ± 0.87%, 41.98% ± 0.8%, and 23.45% ± 0.66%, respectively. The nonprotein fraction in the extracellular fluid was most likely the key component in L. lactis CAMT22361 and hence would be the most desirable cellular component to be used to remove T-2 from food or feed.

  9. Thermally induced dephasing of high power second harmonic generation in MgO: LiNbO3 waveguides

    Institute of Scientific and Technical Information of China (English)

    Guohui Li; Xinye Xu

    2011-01-01

    High power second harmonic generation (SHG) in MgO-doped LiNbO3 waveguides is investigated using a three-dimensional (3D) coupled thermo-optical model. Simulations performed for a 1111.6-nm fundamental laser show the influence of the absorptions and the thermally induced dephasing on the conversion efficiencies of the different waveguides. The onset of the thermally induced dephasing effect for each waveguide is also indicated. As a result of high light intensity in the waveguide, nonlinear absorptions are identified as the possible main factors in efficiency losses in specific cases.%High power second harmonic generation (SHG) in MgO-doped LiNbO3 waveguides is investigated using a three-dimensional (3D) coupled thermo-optical model.Simulations performed for a 1111.6-nm fundamental laser show the influence of the absorptions and the thermally induced dephasing on the conversion efficiencies of the different waveguides.The onset of the thermally induced dephasing effect for each waveguide is also indicated.As a result of high light intensity in the waveguide,nonlinear absorptions are identified as the possible main factors in efficiency losses in specific cases.

  10. Hole spin dephasing time associated to hyperfine interaction in quantum dots

    OpenAIRE

    Testelin, C.; Bernardot, F.; Eble, B.; Chamarro, M.

    2009-01-01

    The spin interaction of a hole confined in a quantum dot with the surrounding nuclei is described in terms of an effective magnetic field. We show that, in contrast to the Fermi contact hyperfine interaction for conduction electrons, the dipole-dipole hyperfine interaction is anisotropic for a hole, for both pure or mixed hole states. We evaluate the coupling constants of the hole-nuclear interaction and demonstrate that they are only one order of magnitude smaller than the coupling constants...

  11. High resolution MR angiography with rephasing and dephasing sequences for selective vascular imaging of arteries

    Energy Technology Data Exchange (ETDEWEB)

    Seiderer, M.; Laub, G.; Staebler, A.; Yousry, P.; Lauterjung, L.

    1988-03-01

    With rephasing and dephasing sequences the vascular system is imaged with high or low signal intensity whereas stationary tissue is imaged with identical signal intensity. With images recorded in systole and diastole followed by image subtraction separate imaging of arteries or veins without background superposition is possible. 13 patients with vascular lesions of the lower extremities and 7 volunteers were examined. Vascular stenosis, aneurysm, dilatation, occlusion and collateral vessels could be imaged similar to digital subtraction angiography. Vessels with a diameter down to 1 mm could be imaged. The large slice thickness up to 80 mm results in projection type images where the vascular tree is imaged over the whole field of view and without partial volume effects.

  12. Disorder and dephasing as control knobs for light transport in optical fiber cavity networks

    Science.gov (United States)

    Viciani, Silvia; Gherardini, Stefano; Lima, Manuela; Bellini, Marco; Caruso, Filippo

    2016-11-01

    Transport phenomena represent a very interdisciplinary topic with applications in many fields of science, such as physics, chemistry, and biology. In this context, the possibility to design a perfectly controllable experimental setup, where to tune and optimize its dynamics parameters, is a challenging but very relevant task to emulate, for instance, the transmission of energy in light harvesting processes. Here, we experimentally build a scalable and controllable transport emulator based on optical fiber cavity networks where the system noise parameters can be finely tuned while maximizing the transfer efficiency. In particular, we demonstrate that disorder and dephasing noise are two control knobs allowing one to play with constructive and destructive interference to optimize the transport paths towards an exit site. These optical setups, on one side, mimic the transport dynamics in natural photosynthetic organisms and, on the other, are very promising platforms to artificially design optimal nanoscale structures for novel, more efficient, clean energy technologies.

  13. Nonlocality threshold for entanglement under general dephasing evolutions: a case study

    Science.gov (United States)

    Lo Franco, Rosario

    2016-06-01

    Determining relationships between different types of quantum correlations in open composite quantum systems is important since it enables the exploitation of a type by knowing the amount of another type. We here review, by giving a formal demonstration, a closed formula of the Bell function, witnessing nonlocality, as a function of the concurrence, quantifying entanglement, valid for a system of two noninteracting qubits initially prepared in extended Werner-like states undergoing any local pure-dephasing evolution. This formula allows for finding nonlocality thresholds for the concurrence depending only on the purity of the initial state. We then utilize these thresholds in a paradigmatic system where the two qubits are locally affected by a quantum environment with an Ohmic class spectrum. We show that steady entanglement can be achieved and provide the lower bound of initial state purity such that this stationary entanglement is above the nonlocality threshold thus guaranteeing the maintenance of nonlocal correlations.

  14. MicroRNAs 9 and 370 Association with Biochemical Markers in T2D and CAD Complication of T2D.

    Science.gov (United States)

    Motawae, Tarek M; Ismail, Manal F; Shabayek, Marwa I; Seleem, Mae M

    2015-01-01

    MicroRNAs (miRNAs) are small non coding RNAs with essential roles, of which any alteration leads to several conditions. Their roles in diabetes (DM) and its vascular complications have not been completely assessed. to study the association of two miRNAs; 9 and 370, with biochemical parameters of type 2 diabetic (T2D), dyslipidemia and coronary artery disease (CAD). Blood samples were taken from 200 subjects of both genders, in the Outpatient clinic of Al Qasr El-Einy teaching hospitals, in which levels of both miRNAs (using real time PCR) and routine parameters were measured. Subjects were divided over four groups, 50 in each group as follows; patients with T2D, patients with CAD, patients with T2D and CAD, and healthy control subjects. miRNA 9 levels were expected to be over expressed in diabetic patients, while miRNA 370 levels were expected to be over expressed in those suffering from CAD and their association with CAD complication of T2D. miRNA 9 levels were significantly higher in T2D patients and T2D patients with CAD, (1.18±0.07, and 1.31±0.08 respectively), while miRNA 370 levels were significantly higher in T2D patients, CAD patients, and T2D patients with CAD (0.59±0.05, 1.00±0.05, and 1.20±0.06 respectively), compared to control group at p = 0.000. In addition both miRNAs were still significantly associated with each other even after conducting multiple regression analysis. This study associates the possible role of miRNAs in the diagnosis/prognosis of CAD complication of T2D.

  15. T2Candida Provides Rapid and Accurate Species Identification in Pediatric Cases of Candidemia.

    Science.gov (United States)

    Hamula, Camille L; Hughes, Kenneth; Fisher, Brian T; Zaoutis, Theoklis E; Singh, Ila R; Velegraki, Aristea

    2016-06-01

    The goal of this study is to assess the ability of the T2Candida platform (T2 Biosystems, Lexington, MA) to accurately identify Candida species from pediatric blood specimens with low volumes. Whole blood from 15 children with candidemia was collected immediately following blood culture draw. The amount of blood required by the system was reduced by pipetting whole blood directly onto the T2Candida cartridge. Specimens were subsequently run on the T2Dx Instrument (T2 Biosystems). The T2Candida panel provided the appropriate result for each specimen compared with blood culture-based species identification and correctly identified 15 positive and nine negative results in 3 to 5 hours. While the time to species identification for blood culture was not reported, the T2Candida results include species data. T2Candida can be used to efficiently diagnose or rule out candidemia using low-volume blood specimens from pediatric patients. This could result in improved time to appropriate antifungal therapy or reduction in unnecessary empirical antifungal therapy. © American Society for Clinical Pathology, 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  16. Quantitative evaluation of hyaline articular cartilage T2 maps of knee and determine the relationship of cartilage T2 values with age, gender, articular changes.

    Science.gov (United States)

    Cağlar, E; Şahin, G; Oğur, T; Aktaş, E

    2014-11-01

    To identify changes in knee joint cartilage transverse relaxation values depending on the patient's age and gender and to investigate the relationship between knee joint pathologies and the transverse relaxation time. Knee MRI images of 107 symptomatic patients with various pathologic knee conditions were analyzed retrospectively. T2 values were measured at patellar cartilage, posteromedial and posterolateral femoral cartilage adjacent to the central horn of posterior meniscus. 963 measurements were done for 107 knees MRI. Relationship of T2 values with seven features including subarticular bone marrow edema, subarticular cysts, marginal osteophytes, anterior-posterior cruciate and collateral ligament tears, posterior medial and posterior lateral meniscal tears, synovial thickening and effusion were analyzed. T2 values in all three compartments were evaluated according to age and gender. A T2 value increase correlated with age was present in all three compartments measured in the subgroup with no knee joint pathology and in all patient groups. According to the ROC curve, an increase showing a statistically significant difference was present in the patient group aged over 40 compared to the patient group aged 40 and below in all patient groups. There is a statistically difference at T2 values with and without subarticular cysts, marginal osteophytes, synovial thickening and effusion. T2 relaxation time showed a statistically significant increase in the patients with a medial meniscus tear compared to those without a tear and no statistically significant difference was found in T2 relaxation times of patients with and without a posterior lateral meniscus tear. T2 cartilage mapping on MRI provides opportunity to exhibit biochemical and structural changes related with cartilage extracellular matrix without using invasive diagnostic methods.

  17. Differential Association of T-2 and T-2 Tetraol with Mammalian Cells

    Science.gov (United States)

    1989-01-01

    toxicities of trichothecenes . In Mycotoxins expect the rate of tetraol uptake to be the same as the uptake in Human and Animal Health, ed. by .1. V...specific T-2 trichothecene toxin may be its lipophilicity. ’- richothecenes are a group of structurally related sesquiter- cell line, CHO, and...isolated CHO-derived ribosomes (Middle- penoids produced by several species of fungi. Trichothecenes brook and Leatherman, 1989a,b). Our data suggested that

  18. T2 selective π Echo-Planar Imaging for porous media MRI

    Science.gov (United States)

    Xiao, Dan; Balcom, Bruce J.

    2017-04-01

    The π Echo Planar Imaging (PEPI) method has recently been modified to permit proton density imaging of fluids in porous media with moderate T2 and short T2∗ signal components. In many applications, it is desirable to discriminate multiple T2 components within each image voxel. T2 selective imaging is explored in this paper through adiabatic inversion as a magnetization preparation with PEPI readout. When prior information of the sample relaxation times is known, responses of different species to broadband adiabatic inversion pulses can be predicted by Bloch equation simulation. Different relaxation components can be acquired by combining the images with and without inversion preparation pulses. T2 weighting can be easily introduced in the PEPI sequence by shifting the spatial encoding gradients based on its spin echo nature. T2 decay curves can be extracted for each image voxel from a series of T2 weighted images and spatially resolved T2 distributions can be generated. This method is reliable but slow. The two methods were implemented to image porous media samples with PEPI the common basis of spatial resolution. The results of both methods agree remarkably well.

  19. The value of MR T2-mapping in muscular disorders%MR T2 mapping在肌肉疾病中的应用价值

    Institute of Scientific and Technical Information of China (English)

    孙露露; 张祥林; 潘诗农

    2014-01-01

    MRI因其多平面、多序列、高分辨力等特点对肌肉组织疾病的诊断具有重要价值,特别是近年新发展起来的MRI T2 mapping技术,不但能从分子水平评价关节软骨和椎间盘、中枢神经系统损伤及退化性疾病、肿瘤良恶性等情况,还逐渐应用于肌肉组织成像。T2 mapping可以通过测量组织T2值来定量分析组织内部成分的变化,在疾病早期准确诊断、病情发展程度和疗效的判断上发挥重要作用。就T2 mapping的基本原理及在肌肉疾病中的研究应用进展予以综述。%MRI is of important value to the diagnosis of muscular diseases due to its multiple planes, multiple sequences, high resolution, etc. T2 mapping is a new emerging technology of MRI and is mainly used to evaluate articular cartilage and intervertebral disc at the molecular level, central nervous system damage and degenerative diseases, and benign and malignant tumors. In recent years, it has been gradually applied in muscle tissue imaging. T 2 mapping can quantificationally analyze the changes in composition of the organization by measuring T 2 relaxation time, and it plays important roles in early and accurate diagnosis, prediction of disease development and evaluation of therapeutic effect. The basic principle of T2 mapping and the progress of its research application in muscle diseases were reviewed.

  20. Current profile modification experiments in EXTRAP T2R

    Science.gov (United States)

    Cecconello, M.; Malmberg, J.-A.; Spizzo, G.; Chapman, B. E.; Gravestjin, R. M.; Franz, P.; Piovesan, P.; Martin, P.; Drake, J. R.

    2004-01-01

    Pulsed poloidal current drive (PPCD) experiments have been conducted in the resistive shell EXTRAP T2R reversed-field pinch experiment. During the current profile modification phase, the fluctuation level of the m = 1 internally resonant tearing modes decreases, and the velocity of these modes increases. The m = 0 modes are not affected during PPCD, although termination occurs with a burst in the m = 0 amplitude. The PPCD phase is characterized by an increase in the central electron temperature (up to 380 eV) and in the soft x-ray signal. Spectroscopic observations confirm an increase in the central electron temperature. During PPCD, the plasma poloidal beta increases to 14%, and the estimated energy confinement time doubles, reaching 380 µs. The reduction in the fluctuation level and the corresponding increase in the energy confinement time are qualitatively consistent with a reduction in parallel transport along stochastic magnetic field lines.

  1. Biochemical T2* MR quantification of ankle arthrosis in pes cavovarus.

    Science.gov (United States)

    Krause, Fabian G; Klammer, Georg; Benneker, Lorin M; Werlen, Stefan; Mamisch, Tallal C; Weber, Martin

    2010-12-01

    Pes cavovarus affects the ankle biomechanics and may lead to ankle arthrosis. Quantitative T2 STAR (T2*) magnetic resonance (MR) mapping allows high resolution of thin cartilage layers and quantitative grading of cartilage degeneration. Detection of ankle arthrosis using T2* mapping in cavovarus feet was evaluated. Eleven cavovarus patients with symptomatic ankle arthrosis (13 feet, mean age 55.6 years, group 1), 10 cavovarus patients with no or asymptomatic, mild ankle arthrosis (12 feet, mean age 41.8 years, group 2), and 11 controls without foot deformity (18 feet, mean age 29.8 years, group 3) had quantitative T2* MR mapping. Additional assessment included plain radiographs and the American Orthopaedic Foot and Ankle Society (AOFAS) score (groups 1 and 2 only). Mean global T2* relaxation time was significantly different between groups 1 and 2 (p = 0.001) and groups 1 and 3 (p = 0.017), but there was no significance for decreased global T2* values in group 2 compared to group 3 (p = 0.345). Compared to the medial compartment T2* values of the lateral compartment were significantly (p = 0.025) higher within group 1. T2* values in the medial ankle joint compartment of group 2 were significantly lower than those of group 1 (p = 0.019). Ankle arthrosis on plain radiographs and the AOFAS score correlated significantly with T2* values in the medial compartment of group 1 (p = 0.04 and 0.039, respectively). Biochemical, quantitative T2* MR mapping is likely effective to evaluate ankle arthrosis in cavovarus feet but further studies are required.

  2. Mono-Exponential Fitting in T2-Relaxometry: Relevance of Offset and First Echo.

    Directory of Open Access Journals (Sweden)

    David Milford

    Full Text Available T2 relaxometry has become an important tool in quantitative MRI. Little focus has been put on the effect of the refocusing flip angle upon the offset parameter, which was introduced to account for a signal floor due to noise or to long T2 components. The aim of this study was to show that B1 imperfections contribute significantly to the offset. We further introduce a simple method to reduce the systematic error in T2 by discarding the first echo and using the offset fitting approach.Signal curves of T2 relaxometry were simulated based on extended phase graph theory and evaluated for 4 different methods (inclusion and exclusion of the first echo, while fitting with and without the offset. We further performed T2 relaxometry in a phantom at 9.4T magnetic resonance imaging scanner and used the same methods for post-processing as in the extended phase graph simulated data. Single spin echo sequences were used to determine the correct T2 time.The simulation data showed that the systematic error in T2 and the offset depends on the refocusing pulse, the echo spacing and the echo train length. The systematic error could be reduced by discarding the first echo. Further reduction of the systematic T2 error was reached by using the offset as fitting parameter. The phantom experiments confirmed these findings.The fitted offset parameter in T2 relaxometry is influenced by imperfect refocusing pulses. Using the offset as a fitting parameter and discarding the first echo is a fast and easy method to minimize the error in T2, particularly for low to intermediate echo train length.

  3. Development and operational experience of magnetic horn system for T2K experiment

    CERN Document Server

    Sekiguchi, T; Fujii, Y; Hagiwara, M; Hasegawa, T; Hayashi, K; Ishida, T; Ishii, T; Kobayashi, H; Kobayashi, T; Koike, S; Koseki, K; Maruyama, T; Matsumoto, H; Nakadaira, T; Nakamura, K; Nakayoshi, K; Nishikawa, K; Oyama, Y; Sakashita, K; Shibata, M; Suzuki, Y; Tada, M; Takahashi, K; Tsukamoto, T; Yamada, Y; Yamanoi, Y; Yamaoka, H; Ichikawa, A K; Kubo, H; Butcher, Z; Coleman, S; Missert, A; Spitz, J; Zimmerman, E D; Tzanov, M; Bartoszek, L

    2015-01-01

    A magnetic horn system to be operated at a pulsed current of 320 kA and to survive high-power proton beam operation at 750 kW was developed for the T2K experiment. The first set of T2K magnetic horns was operated for over 12 million pulses during the four years of operation from 2010 to 2013, under a maximum beam power of 230 kW, and $6.63\\times10^{20}$ protons were exposed to the production target. No significant damage was observed throughout this period. This successful operation of the T2K magnetic horns led to the discovery of the $\

  4. Spatial variation of T2 values of femoral condyle cartilage of knee using MR T2 mapping%磁共振成像研究膝股骨髁软骨T2值空间分布

    Institute of Scientific and Technical Information of China (English)

    陈其春; 冯阳; 宗敏; 邹月芬

    2011-01-01

    Objective To study the spatial variation of T2 relaxation time (T2 value) of femoral condyle cartilage of knee in the healthy adults and early osteoarthritis(OA) patients. Methods T2 values of femoral condyle cartilage were evaluated with Siemens 3. 0 T MR in 25 healthy knee joints (20 subjects,age ranged:25 - 38 years with mean age 28. 7 + 4. 5 years) and 31 knee joints with early osteoarthritis(OA) (27 subjects,age ranged:40 - 78 years with mean age 54. 2 + 11 years). T2 values of non-weight-bearing site and weigh-bearing site of medial femoral condyle and lateral femoral condyle were measured respectively on T2-mapping images. Statistical differences were analyzed. Results T2 values of weight-bearing site of femoral condyle were higher obviously than that of non-weight-bearing site in healthy group and early OA group, there were significant differences between them(.F=22. 151,54. 670 ,P 0. 05). Conclusion The spatial variation of T2 value of femoral condyle cartilage of knee in the healthy adults and early OA patients is of certain characteristics,that is of reference value in monitoring cartilage change of early OA. And T2 value is influenced by the weight bearing condition.%目的 研究健康成人和早期骨性关节炎(osteoarthritis,OA)病人膝关节股骨内外髁软骨横向弛豫时间(T2值)空间分布.方法 采用Siemens 3.0T磁共振,正常组(20例;年龄25~38岁,平均28.7岁±4.5岁)25个膝关节和早期OA病人组(27例;年龄40~78岁,平均54.2岁±11岁)31个膝关节,应用T2图成像观察和测量2组股骨内外侧髁非负重区与负重区软骨T2值,并进行统计学分析.结果 正常组与早期OA组股骨髁负重区软骨平均T2值[(51.1±4.3) ms,(58.9±4.0) ms]明显高于各自非负重区[(47.2±3.8) ms,(53.5±4.1) ms],差异有统计学意义(F值分别为22.151和54.670,P值均0.05).结论 健康成人和早期OA病人膝关节股骨内外髁软骨T2值具有特定空间分布特点,对量化监测早期OA软骨病变

  5. Heat transport modelling in EXTRAP T2R

    Science.gov (United States)

    Frassinetti, L.; Brunsell, P. R.; Cecconello, M.; Drake, J. R.

    2009-02-01

    A model to estimate the heat transport in the EXTRAP T2R reversed field pinch (RFP) is described. The model, based on experimental and theoretical results, divides the RFP electron heat diffusivity χe into three regions, one in the plasma core, where χe is assumed to be determined by the tearing modes, one located around the reversal radius, where χe is assumed not dependent on the magnetic fluctuations and one in the extreme edge, where high χe is assumed. The absolute values of the core and of the reversal χe are determined by simulating the electron temperature and the soft x-ray and by comparing the simulated signals with the experimental ones. The model is used to estimate the heat diffusivity and the energy confinement time during the flat top of standard plasmas, of deep F plasmas and of plasmas obtained with the intelligent shell.

  6. Efficacy of T-2 toxin detoxifying agent in broiler chickens

    Directory of Open Access Journals (Sweden)

    Nešić V.

    2012-01-01

    Full Text Available This investigation was conducted in order to investigate the efficacy of the detoxifying agent Mycofix® Plus (MP in the prevention and/or alleviation in vivo adverse effects of T-2 toxin in broilers. In addition, the adsorbing potential of MP was estimated in vitro. Mean degradation levels of T-2 toxin with MP in vitro, as measured by HPTLC, varied from 26.06 to 31.02 % and the adsorption ability was elevated in acidic environment (pH 3. In vivo trial was performed on 160 one day old "Ross" broiler chicks and lasted for 21 days. Birds were divided into 4 equal groups as follows: Group 1 - negative control; Group 2 - positive control - 2 ppm T-2 toxin; Group 3 - 2 ppm T-2 toxin+2 kg/t MP; Group 4 - 2 kg/t MP. Broilers fed the diet containing 2 mg/kg of T-2 toxin without MP developed typical T-2 toxicosis. Birds that were fed the diet containing both T-2 and MP had better performances and no oral ulcerations as the dominant sign of T-2 toxicosis were observed. Histopathological examination of tissues originating from birds fed the diet containing T-2 toxin revealed degenerative changes in the oral and small intestine mucosa, necroses of enterocytes and hepatocytes, as well as depletion of lymphocytes in the bursa Fabricii. Immunohistochemical examination also revealed negative effects of T-2 toxin on cells proliferation in intestineal and bile duct mucosa, as well as on lymphocytes from bursa Fabricii. The macroscopic and microscopic structure of the liver, intestine and bursa Fabricii of broilers fed a diet containing T-2 toxin and MP was mostly preserved. Cutaneous basophile hypersensitivity reaction was weaker in broilers fed mixtures containing 2 mg/kg T-2 toxin.

  7. Myocardial T2* Mapping with Ultrahigh Field Magnetic Resonance: Physics and Frontier Applications

    Directory of Open Access Journals (Sweden)

    Till Huelnhagen

    2017-06-01

    Full Text Available Cardiovascular magnetic resonance imaging (CMR has become an indispensable clinical tool for the assessment of morphology, function and structure of the heart muscle. By exploiting quantification of the effective transverse relaxation time (T2* CMR also affords myocardial tissue characterization and probing of cardiac physiology, both being in the focus of ongoing research. These developments are fueled by the move to ultrahigh magnetic field strengths, which permits enhanced sensitivity and spatial resolution that help to overcome limitations of current clinical MR systems with the goal to contribute to a better understanding of myocardial (pathophysiology in vivo. In this context, the aim of this report is to introduce myocardial T2* mapping at ultrahigh magnetic fields as a promising technique to non-invasively assess myocardial (pathophysiology. For this purpose the basic principles of T2* assessment, the biophysical mechanisms determining T2* and (preclinical applications of myocardial T2* mapping are presented. Technological challenges and solutions for T2* sensitized CMR at ultrahigh magnetic field strengths are discussed followed by a review of acquisition techniques and post-processing approaches. Preliminary results derived from myocardial T2* mapping in healthy subjects and cardiac patients at 7.0 T are presented. A concluding section discusses remaining questions and challenges and provides an outlook on future developments and potential clinical applications.

  8. T2 relaxometry of the infrapatellar fat pad after arthroscopic surgery

    Energy Technology Data Exchange (ETDEWEB)

    Torriani, Martin; Bredella, Miriam A. [Massachusetts General Hospital and Harvard Medical School, Musculoskeletal Imaging and Intervention, Department of Radiology, Boston, MA (United States); Taneja, Atul K. [Hospital do Coracao (HCor), Teleimagem, and Hospital Israelita Albert Einstein, Division of Musculoskeletal Imaging, Department of Radiology, Sao Paulo (Brazil); Hosseini, Ali; Li, Guoan [Massachusetts General Hospital and Harvard Medical School, Bioengineering Laboratory, Department of Orthopedics, Boston, MA (United States); Gill, Thomas J. [Massachusetts General Hospital and Harvard Medical School, Sports Medicine Center, Department of Orthopedics, Boston, MA (United States)

    2014-03-15

    To investigate the T2 relaxation values of the infrapatellar fat pad (IFP) after arthroscopic surgery. This study was approved by the institutional review board; all individuals signed informed consent. We performed MRI in 16 knees from 8 subjects. Prior to imaging, each subject had unilateral arthroscopic knee surgery and an asymptomatic non-operated contralateral knee. We used a 10-echo multiple-TE fast-spin echo pulse sequence for creation of T2 relaxation time maps. Two musculoskeletal radiologists independently placed regions of interest in the IFP, suprapatellar subcutaneous and deep intermuscular adipose tissue. Qualitative assessments were performed to assess fibrotic changes affecting patellar retinaculum and IFP. Statistical analyses of T2 values determined differences between groups, correlation with time after surgery, and cut-off values to differentiate groups. The average time between arthroscopy and imaging was 3.5 ± 0.4 years. IFP of knees with prior surgery had significantly shorter mean T2 values (133 ± 14 ms) compared with control knees (147 ± 8 ms, P = 0.03). There was no significant difference between operated and control knees regarding T2 values of suprapatellar subcutaneous (P = 0.3) or deep intermuscular adipose tissue (P = 0.2). There was no correlation between IFP T2 values and time after surgery (P > 0.2). IFP T2 values ≤ 139 ms had 75 % sensitivity and 88 % specificity in identifying prior arthroscopy. Shortening of T2 relaxation values is present in IFP chronically after arthroscopic surgery and may be an indicator of adipose tissue fibrosis. (orig.)

  9. Phonon mechanisms of nonlinear decay and dephasing of mesoscopic vibrational systems

    Science.gov (United States)

    Atalaya, Juan; Kenny, Thomas W.; Dykman, Mark I.

    2015-03-01

    The frequencies and the decay rates of mesoscopic oscillators depend on vibration amplitudes. Nonlinear decay has been seen recently in various nano- and micro-mechanical systems. Here we consider a microscopic mechanism of nonlinear decay, the nonlinear coupling of the vibrational mode of interest, for example, a flexural mode, to other vibrations. Typically, the modes of interest have low eigenfrequencies ω0. Their decay comes from the coupling to acoustic-phonon type vibrations with much higher frequency and density of states. Thus, nonlinear decay requires quartic anharmonic coupling or cubic anharmonicity in the higher order. We find the decay rate for the inverse lifetime of the involved phonons, which is determined by the internal nonlinearity and the boundary scattering, being either much larger or smaller than ω0. The results extend the thermo-elastic, Akhiezer, and Landau-Rumer decay theory to nonlinear decay of mesoscopic modes and make specific predictions on the temperature and frequency dependence of the decay rate for different types of systems. We show that nonlinear decay is invariably accompanied by dephasing. We also show that in nano-electro-mechanical systems the decay rate can be electrostatically controlled.

  10. Characterization of alkyl carbon in forest soils by CPMAS 13C NMR spectroscopy and dipolar dephasing

    Science.gov (United States)

    Kogel-Knabner, I.; Hatcher, P.G.

    1989-01-01

    Samples obtained from forest soils at different stages of decomposition were treated sequentially with chloroform/methanol (extraction of lipids), sulfuric acid (hydrolysis), and sodium chlorite (delignification) to enrich them in refractory alkyl carbon. As revealed by NMR spectroscopy, this treatment yielded residues with high contents of alkyl carbon. In the NMR spectra of residues obtained from litter samples, resonances for carbohydrates are also present, indicating that these carbohydrates are tightly bound to the alkyl carbon structures. During decomposition in the soils this resistant carbohydrate fraction is lost almost completely. In the litter samples the alkyl carbon shows a dipolar dephasing behavior indicative of two structural components, a rigid and a more mobile component. As depth and decomposition increase, only the rigid component is observed. This fact could be due to selective degradation of the mobile component or to changes in molecular mobility during decomposition, e.g., because of an increase in cross linking or contact with the mineral matter of the soil.

  11. Evaluation of the nondiabaticity of quantum molecular dynamics with the dephasing representation of quantum fidelity

    CERN Document Server

    Zimmermann, Tomas

    2010-01-01

    We propose an approximate method for evaluating the importance of non-Born-Oppenheimer effects on the quantum dynamics of nuclei. The method uses a generalization of the dephasing representation (DR) of quantum fidelity to several diabatic potential energy surfaces and its computational cost is the cost of dynamics of a classical phase space distribution. It can be implemented easily into any molecular dynamics program and also can utilize on-the-fly ab initio electronic structure information. We test the methodology on three model problems introduced by Tully and on the photodissociation of NaI. The results show that for dynamics close to the diabatic regime the decay of fidelity due to nondiabatic effects is described accurately by the DR. In the nearly diabatic regime, unlike the mixed quantum-classical methods such as surface hopping or Ehrenfest dynamics, the DR can capture more subtle quantum effects than the population transfer between potential energy surfaces. Hence we propose using the DR to estimat...

  12. Dynamics of tripartite quantum entanglement and discord under a classical dephasing random telegraph noise

    Science.gov (United States)

    Kenfack, Lionel Tenemeza; Tchoffo, Martin; Fai, Lukong Cornelius

    2017-02-01

    We address the dynamics of quantum correlations, including entanglement and quantum discord of a three-qubit system interacting with a classical pure dephasing random telegraph noise (RTN) in three different physical environmental situations (independent, mixed and common environments). Two initial entangled states of the system are examined, namely the Greenberger-Horne-Zeilinger (GHZ)- and Werner (W)-type states. The classical noise is introduced as a stochastic process affecting the energy splitting of the qubits. With the help of suitable measures of tripartite entanglement (entanglement witnesses and lower bound of concurrence) and quantum discord (global quantum discord and quantum dissension), we show that the evolution of quantum correlations is not only affected by the type of the system-environment interaction but also by the input configuration of the qubits and the memory properties of the environmental noise. Indeed, depending on the memory properties of the environmental noise and the initial state considered, we find that independent, common and mixed environments can play opposite roles in preserving quantum correlations, and that the sudden death and revival phenomena or the survival of quantum correlations may occur. On the other hand, we also show that the W-type state has strong dynamics under this noise than the GHZ-type ones.

  13. Quantum dynamics of a driven two-level molecule with variable dephasing

    Science.gov (United States)

    Grandi, Samuele; Major, Kyle D.; Polisseni, Claudio; Boissier, Sebastien; Clark, Alex S.; Hinds, E. A.

    2016-12-01

    The longitudinal (Γ1) and transverse (Γ2) decay rates of a two-level quantum system have a profound influence on its evolution. Atomic systems with Γ2=1/2 Γ1 have been studied extensively, but with the rise of solid-state quantum devices it is also important to consider the effect of stronger transverse relaxation due to interactions with the solid environment. Here we study the quantum dynamics of a single organic dye molecule driven by a laser. We measure the variation of Γ2 with temperature and determine the activation energy for thermal dephasing of the optical dipole. Then we measure the second-order correlation function g(2 )(τ ) of the light emitted by the molecule for various ratios Γ2/Γ1 and saturation parameters S . We show that the general solution to the optical Bloch equations accurately describes the observed quantum dynamics over a wide range of these parameters, and we discuss the limitations of the various approximate expressions for g(2 )(τ ) that appear in the literature.

  14. T2-weighted MRI of the uterus: fast spin echo vs. breath-hold fast spin echo.

    Science.gov (United States)

    Ascher, S M; O'Malley, J; Semelka, R C; Patt, R H; Rajan, S; Thomasson, D

    1999-03-01

    were no statistically significant differences for CNR between the two image sets, although BH T2FSE values for leiomyomata, adenomyosis, and abnormal endometria were higher than those calculated for T2FSE. All pathology detected with T2FSE was detected on BH T2FSE despite the breath-hold sequence's inherently poorer spatial resolution compared with the non-breath-hold sequence. BH T2FSE may be able to replace T2FSE for some uterine applications with a substantial time savings.

  15. Electron transfer mechanism and the locality of the system-bath interaction: a comparison of local, semilocal, and pure dephasing models.

    Science.gov (United States)

    Weiss, Emily A; Katz, Gil; Goldsmith, Randall H; Wasielewski, Michael R; Ratner, Mark A; Kosloff, Ronnie; Nitzan, Abraham

    2006-02-21

    We simulate the effects of two types of dephasing processes, a nonlocal dephasing of system eigenstates and a dephasing of semilocal eigenstates, on the rate and mechanism of electron transfer (eT) through a series of donor-bridge-acceptor systems, D-B(N)-A, where N is the number of identical bridge units. Our analytical and numerical results show that pure dephasing, defined as the perturbation of system eigenstates through the system-bath interaction, does not disrupt coherent eT because it induces no localization; electron transfer may proceed through superexchange in a system undergoing only pure dephasing. A more physically reasonable description may be obtained via a system-bath interaction that reflects the perturbation of more local electronic structure by local nuclear distortions and dipole interactions. The degree of locality of this interaction is guided by the structure of the system Hamiltonian and by the nature of the measurement performed on the system (i.e., the nature of the environment). We compare our result from this "semilocal" model with an even more local phenomenological dephasing model. We calculate electron transfer rate by obtaining nonequilibrium steady-state solutions for the elements of a reduced density matrix; a semigroup formalism is used to write down the dissipative part of the equation of motion.

  16. Evaluation of cartilage repair tissue after biomaterial implantation in rat patella by using T2 mapping.

    Science.gov (United States)

    Watrin-Pinzano, A; Ruaud, J-P; Cheli, Y; Gonord, P; Grossin, L; Bettembourg-Brault, I; Gillet, P; Payan, E; Guillot, G; Netter, P; Loeuille, D

    2004-12-01

    To evaluate the ability of MR T2 mapping (8.5 T) to characterize ex vivo longitudinally, morphologically and quantitatively, alginate-based tissue engineering in a rat model of patellar cartilage chondral focal defect. Calibrated rat patellar cartilage defects (1.3 mm) were created at day 0 (D0) and alginate sponge with (Sp/C+) or without (Sp/C-) autologous chondrocytes were implanted. Animals were sacrificed sequentially at D20, D40 and D60 after surgery and dissected patellae underwent MRI exploration (8.5 T). T2 values were calculated from eight SE images by using nonlinear least-squares curve fitting on a pixel-by-pixel basis (constant repetition time of 1.5 s, eight different echo times: 5.5, 7.5, 10.5, 12.5, 15.0, 20.0, 25.0 and 30.0 ms). On the T2 map, acquired in a transversal plane through the repair zone, global T2 values and zonal variation of T2 values of repair tissue were evaluated versus control group and compared with macroscopic score and histological studies (toluidine blue, sirius red and hematoxylin-eosin). "Partial", "total" and "hypertrophic" repair patterns were identified. At D40 and D60, Sp/C+ group was characterized by a higher proportion of "total" repair in comparison to Sp/C- group. At D60, the proportion of "hypertrophic" repair was two fold in Sp/C- group versus Sp/C+ group. As confirmed morphologically and histologically, the T2 map also permitted the distinction of three types of repair tissue: "total", "partial" and "hypertrophic". "Total" repair tissue was characterized by high T2 values versus normal cartilage (p<0.05). Zonal variation, reflecting the collagen network organization, appeared only at D60 for Sp/C+ group (p<0.05). "Hypertrophic" tissue, mainly observed at D60, presented high T2 global values without zonal variation with cartilage depth. These results confirm the potency of the MR T2 map (8.5 T) to characterize macroscopically and microscopically the patterns of the scaffold guided-tissue repair of a focal chondral

  17. [Immunochromatographic Test System for the Detection of T-2 Toxin].

    Science.gov (United States)

    Petrakova, A V; Urusova, A E; Voznyak, M V; Zherdeva, A V; Dzantiev, B B

    2015-01-01

    An immunochromatographic test system was developed for the detection of T-2 toxin (T2T), which is one of priority contaminants of cereals. The detection is based on the competition between T2T in the sample and the T2T-protein conjugate immobilized on the test strip for the binding to the complexes of anti-T2T antibodies with gold nanoparticles serving as the marker. The results of the competition are recorded as the coloration in the test zone of the test strip produced by the marker. The optimum dilution of the sample for the reliable high-sensitivity analysis corresponds to the final methanol concentration equal to 20%. The deceleration of the movement of reactants along the test strip due to the use of additional membranes impregnated with 10% BSA resulted in the decrease in the detection limit of T2T. The test system was examined for the detection of T2T in water-methanol extracts of maize grains. The disappearance of the color in the test zone, which attests to the presence of mycotoxin, was observed for grain samples containing T2T at a concentration of 53 μg/kg or more (the final T2T concentration in the immunochromatorgaphic assay is 3 ng/mL). The video-digital detection limit of T2T is 16 μg/kg (0.9 ng/mL). The duration of the assay is 15 min. The results of the present study suggest that the developed test system is suitable for the control of the maximum allowable T2T content.

  18. Myocardial T1 and T2 mapping: Techniques and clinical applications

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Pan Ki; Hong, Yoo Jin; Im, Dong Jin [Dept. of Radiology and Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of); and others

    2017-01-15

    Cardiac magnetic resonance (CMR) imaging is widely used in various medical fields related to cardiovascular diseases. Rapid technological innovations in magnetic resonance imaging in recent times have resulted in the development of new techniques for CMR imaging. T1 and T2 image mapping sequences enable the direct quantification of T1, T2, and extracellular volume fraction (ECV) values of the myocardium, leading to the progressive integration of these sequences into routine CMR settings. Currently, T1, T2, and ECV values are being recognized as not only robust biomarkers for diagnosis of cardiomyopathies, but also predictive factors for treatment monitoring and prognosis. In this study, we have reviewed various T1 and T2 mapping sequence techniques and their clinical applications.

  19. Combined T2 and T1 measurements for improved perfusion and permeability studies in high field using dynamic contrast enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Bazelaire, Cedric de [Saint Louis Hospital, Radiology Department, Paris, Cedex 10 (France); Beth Israel Deaconess Medical Center and Harvard Medical School, Department of Radiology, Cambridge, MA (United States); Rofsky, Neil M.; Duhamel, Guillaume; Zhang, Jingbo; Alsop, David C. [Beth Israel Deaconess Medical Center and Harvard Medical School, Department of Radiology, Cambridge, MA (United States); Michaelson, M.D. [Massachusetts General Hospital, Department of Hematology/Oncology, Boston, MA (United States); George, Daniel [Dana Farber Cancer Institute, Department of Adult Oncology, Boston, MA (United States)

    2006-09-15

    This study analyzed the T2* effect of extracellularly distributed gadolinium contrast agents in arterial blood during tumor studies using T1-weighted sequences at high field strength. A saturation-prepared dual echo sequence with echo times of 1.5 and 3.5 ms was employed at 3 T to simultaneously characterize T1 and T2* of arterial blood during bolus administration of Gd-DTPA in 28 patients with body tumors. T2* effect and T1 effect of Gd-DTPA on image intensity of whole blood were calibrated in human blood samples with different concentrations of contrast agent. T2* was used to estimate concentration near the peak of the bolus. T1 was used to measure lower concentrations when T2* was not significant. T2* was measurable on calibration curves for Gd-DTPA concentrations higher than 4 mM. This concentration was exceeded in 18 patients. The mean signal intensity reduction because of T2* effect was estimated at 22{+-}14% of the T2* compensated signal. Using T2* measurements reduced underestimations of peak arterial Gd-DTPA concentration (59{+-}38%) and overestimation of permeability K{sup trans} (58%). The T2* effect of gadolinium contrast agents should therefore be accounted for when performing tumors study with T1-weighted sequences at high field strength. (orig.)

  20. Neutrino Oscillation Experiments with J-PARC: T2K, T2K-II and Hyper-Kamiokande

    CERN Document Server

    CERN. Geneva

    2016-01-01

    The T2K experiment started the operation in 2010, and advances neutrino physics with the discovery of electron neutrino appearance in the muon neutrino beam and precision measurements of neutrino oscillation parameters. In 2016, the measurements of anti-neutrino oscillation directly constrain CP violation in neutrino oscillation. In this colloquium, we introduce many physics results from T2K including the most recent one of the CP violation. By utilizing the J-PARC neutrino beam, the upgrade of the T2K experiment (naming T2K-II) is planned and Hyper-Kamiokande is proposed to explore neutrino physics further. In T2K-II, the beam power of J-PARC will be upgraded to 1.3 MW around 2020. Hyper-Kamiokande is the larger Water Cherenkov detector of 520 k...

  1. KyoT2 downregulates airway remodeling in asthma.

    Science.gov (United States)

    Hu, Mei; Ou-Yang, Hai-Feng; Han, Xing-Peng; Ti, Xin-Yu; Wu, Chang-Gui

    2015-01-01

    The typical pathological features of asthma are airway remodeling and airway hyperresponsiveness (AHR). KyoT2, a negative modulator of Notch signaling, has been linked to asthma in several previous studies. However, whether KyoT2 is involved in the regulation of airway remodeling or the modulation of airway resistance in asthma is unclear. In this study, we aimed to evaluate the therapeutic potential of KyoT2 in preventing asthma-associated airway remodeling and AHR. BALB/c mice were used to generate a mouse model of asthma. Additionally, the expression of Hes1 and Notch1 in airway was analyzed using Immunofluorescence examination. The asthmatic mice were intranasally administered adenovirus expressing KyoT2 and were compared to control groups. Furthermore, subepithelial fibrosis and other airway remodeling features were analyzed using hematoxylin and eosin staining, Van Gieson's staining and Masson's trichrome staining. AHR was also evaluated. This study revealed that KyoT2 downregulated the expression of Hes1, repressed airway remodeling, and alleviated AHR in asthmatic mice. It is reasonable to assume that KyoT2 downregulates airway remodeling and resistance in asthmatic mice through a Hes1-dependent mechanism. Therefore, KyoT2 is a potential clinical treatment strategy for asthma.

  2. TRIMS: Validating T2 Molecular Effects for Neutrino Mass Experiments

    Science.gov (United States)

    Lin, Ying-Ting; Bodine, Laura; Enomoto, Sanshiro; Kallander, Matthew; Machado, Eric; Parno, Diana; Robertson, Hamish; Trims Collaboration

    2017-01-01

    The upcoming KATRIN and Project 8 experiments will measure the model-independent effective neutrino mass through the kinematics near the endpoint of tritium beta-decay. A critical systematic, however, is the understanding of the molecular final-state distribution populated by tritium decay. In fact, the current theory incorporated in the KATRIN analysis framework predicts an observable that disagrees with an experimental result from the 1950s. The Tritium Recoil-Ion Mass Spectrometer (TRIMS) experiment will reexamine branching ratio of the molecular tritium (T2) beta decay to the bound state (3HeT+). TRIMS consists of a magnet-guided time-of-flight mass spectrometer with a detector located on each end. By measuring the kinetic energy and time-of-flight difference of the ions and beta particles reaching the detectors, we will be able to distinguish molecular ions from atomic ones and hence derive the ratio in question.We will give an update on simulation software, analysis tools, and the apparatus, including early commissioning results. U.S. Department of Energy Office of Science, Office of Nuclear Physics, Award Number DE-FG02-97ER41020.

  3. Clinical and Hematologic Effects of T-2 Toxin in Rats

    Science.gov (United States)

    2007-11-02

    FREIREICH, E.J. (1978). Phase I clinical evaluation of anguidine. Cancer Treatment Reports, 62, 1497-1502. "PACE, J.G. (1983). Effect of T-2 mycotoxin on...R.W., JR. (1983). Viability uptake and - release of T-2 mycotoxin in Vero cells. Fed. Proc. 42, 3:1983. "" THOMPSON, W.L., and WANNEMACHER, R.W., JR...1984). Detection and quantitation of T-2 mycotoxin with a simplified protein synthesis inhibition assay. Appl. Environ. Microbiol. 48, 1176-1180

  4. Recent neutrino oscillation results from T2K

    Indian Academy of Sciences (India)

    H A Tanaka; on behalf of the T2K Collaboration

    2012-11-01

    The Tokai-to-Kamioka (T2K) experiment studies neutrino oscillations in a ∼ 600 MeV muon neutrino beam sent at 295 km from the Japan Proton Accelerator Complex (J-PARC) to the Super Kamiokande (SK) detector in Kamioka. The primary goals of T2K are to search for the appearance of electron neutrinos at SK resulting from 13 > 0 and to precisely measure 23 and $ m_{32}^{2}$ via disappearance. We report on T2K results obtained from neutrino data taken in 2010 and 2011.

  5. T2L2/Jason-2, first year of processing activities

    Science.gov (United States)

    Exertier, P.

    2009-11-01

    The T2L2 (Time Transfer by Laser Link) project, developed by CNES and OCA will permit the synchronization of remote ultra stable clocks and the determination of their performances over intercontinental distances. The principle is derived from laser telemetry technology with a dedicated space equipment designed to record arrival time of laser pulses at the satellite. T2L2 was accepted in 2005 to be on board the Jason-2 altimetry satellite. It has been successfully launched from Vandenberg (CA, US) in June 2008. T2L2 acquired the first laser pulses a few days after the launch. First analysis permitted to validate some important characteristics of the instrument such as sensitivity, noise, dynamic, event timer precision and ground to space time stability.

  6. Oral methylphenidate challenge selectively decreases putaminal T2 in healthy subjects.

    Science.gov (United States)

    Silveri, Marisa M; Anderson, Carl M; McNeil, Jane F; Diaz, Claudia I; Lukas, Scott E; Mendelson, Jack H; Renshaw, Perry F; Kaufman, Marc J

    2004-11-11

    Despite the recent rise in oral methylphenidate (MPH) abuse, few studies have characterized the time course of oral MPH brain effects in human subjects. Accordingly, this study assessed the hemodynamic effects of oral MPH effects in 11 healthy young adults (six women), by measuring brain transverse relaxation times (T2). T2 can be interpreted as a surrogate marker for, and inversely correlated with, steady-state cerebral blood volume (CBV). Data were acquired from the caudate nucleus, putamen, and thalamus, using a 1.5 T MRI scanner at baseline and serially for 2 h following oral MPH administration (0.5 mg/kg). Physiological and subjective measures and plasma MPH levels also were examined. MPH induced a selective T2 decrease (-1.65+/-0.53 ms) in the putamen (F(6,54)=2.68, PHeartrate, blood pressure and plasma MPH levels increased significantly after drug administration, as well as subjective ratings of "feeling drug effect". T2 decreases may reflect MPH-induced increases in putaminal blood volume. These data suggest that T2 relaxometry can be used to study the time course of regional cerebral blood volume responses to MPH and perhaps to other stimulant drugs.

  7. New Oscillation Results from the T2K experiment

    CERN Document Server

    Izmaylov, Alexander

    2011-01-01

    The T2K (Tokai to Kamioka) experiment is a second generation long baseline neutrino oscillation experiment located in Japan. The main goal is to probe the $\\theta_{13}$ neutrino mixing parameter by looking for $\

  8. Application of Hamamatsu MPPC to T2K Neutrino Detectors

    CERN Document Server

    Yokoyama, M; Gomi, S; Minamino, A; Nagai, N; Nitta, K; Orme, D; Otani, M; Murakami, T; Nakadaira, T; Tanaka, M; Kudenko, Yu; Retière, F; Vacheret, A

    2008-01-01

    A special type of Hamamatsu MPPC, with a sensitive area of 1.3x1.3mm^2 containing 667 pixels with 50x50um^2 each, has been developed for the near neutrino detector in the T2K long baseline neutrino experiment. About 60 000 MPPCs will be used in total to read out the plastic scintillator detectors with wavelength shifting fibers. We report on the basic performance of MPPCs produced for T2K.

  9. 泰国采用DVB-T2

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    泰国内阁于5月20日批准DVB—T2为数字广播标准。泰国国家广播和电信委员会(NBTC)称,泰国商业数字电视服务将采用DVB—T2标准。此变化将影响泰国全部2000万户家庭。

  10. Time-varying pattern of postoperative recurrence risk of early-stage (T1a-T2bN0M0) non-small cell lung cancer (NSCLC): results of a single-center study of 994 Chinese patients.

    Science.gov (United States)

    Zhu, Jian-fei; Feng, Xing-yu; Zhang, Xue-wen; Wen, Ying-sheng; Lin, Peng; Rong, Tie-hua; Cai, Ling; Zhang, Lan-jun

    2014-01-01

    The aim of this study was to analyze the time-varying pattern of recurrence risk of early-stage (T1a-T2bN0M0) non-small cell lung cancer (NSCLC) after surgery using the hazard function and identify patients who might benefit from adjuvant chemotherapy. This retrospective study enrolled 994 patients with early-stage NSCLC who underwent radical surgical resection between January 1999 and October 2009. Survival curves were generated using the Kaplan-Meier method, and the annual recurrence hazard was estimated using the hazard function. The median recurrence-free survival (RFS) was 8.8 years. The life table survival analysis showed that the 1-year, 3-year, 5-year and 10-year recurrence rates were 82.0%, 67.0%, 59.0% and 48.0%, respectively. Approximately 256 (25.7%) patients experienced relapse [locoregional: 32 (3.2%) and distant: 224 (22.5%)], and 162 patients died from cancer. The annual recurrence hazard curve for the entire population showed that the first major recurrence surge reached a maximum 1.6 years after surgery. The curve subsequently declined until reaching a nadir at 7.2 years. A second peak occurred at 8.8 years. An analysis of clinical-pathological factors demonstrated that this double-peaked pattern was present in several subgroups. The presence of a double-peaked pattern indicates that there is a predictable temporal distribution of the recurrence hazard of early-stage NSCLC. The annual recurrence hazard may be an effective method of selecting patients at high risk of recurrence, who may benefit from adjuvant therapy.

  11. Dephasing of Single-Photon Orbital Angular Momentum Qudit States in Fiber: Limits to Correction via Dynamical Decoupling

    Science.gov (United States)

    Gupta, Manish K.; Dowling, Jonathan P.

    2016-06-01

    We analytically derive a decoherence model for orbital angular momentum states of a photon in a multimode optical fiber and show that the rate of decoherence scales approximately exponentially with l2, where l is the azimuthal mode order. We also show numerically that for large values of l the orbital angular momentum photon state completely dephases. However, for lower values of l the decoherence can be minimized by using dynamical decoupling to allow for qudit high-bandwidth quantum communication and similar applications.

  12. Current profile control experiments in EXTRAP T2R

    Science.gov (United States)

    Brunsell, P.; Cecconello, M.; Drake, J.; Franz, P.; Malmberg, J. A.; Marrelli, L.; Martin, P.; Spizzo, G.

    2002-11-01

    EXTRAP T2R is a high aspect ratio (R=1.24 m, a = 0.183 m) reversed-field pinch device, characterised by a double, thin shell system. The simultaneous presence of many m=1, |n| > 11 tearing modes is responsible for a magnetic field turbulence, which is believed to produce the rather high energy and particle transport that is observed in this type of magnetic configuration. In this paper first results from current profile control experiments (PPCD) in a thin shell device are shown. When an edge poloidal electric field is transiently applied, an increase of the electron temperature and of the electron density is seen, which is consistent with an increase of the thermal content of the plasma. At the same time, the soft x-ray emission, measured with a newly installed miniaturised camera, shows a peaking of the profile in the core. Furthermore, the amplitudes of the m=1 tearing modes are reduced and and the rotation velocities increase during PPCD, which is also consistent with a reduction of magnetic turbulence and a heating of the plasma

  13. The effect of thermal annealing on the charge transfer dynamics of a donor-acceptor copolymer and fullerene: F8T2 and F8T2:PCBM.

    Science.gov (United States)

    Garcia-Basabe, Yunier; Yamamoto, Natasha A D; Roman, Lucimara S; Rocco, Maria Luiza M

    2015-05-07

    Ultrafast charge delocalization dynamics in an internal donor-acceptor copolymer poly(9,9-dioctylfluorenyl-co-bithiophene) (F8T2) and its blend with the fullerene derivative [6,6]-phenyl C61 butyric acid methyl ester (PCBM) was studied by resonant Auger spectroscopy measured around sulfur K-edge using the core-hole clock approach. The effect of thermal annealing on the charge transfer delocalization times (τCT) was also investigated. Two main transitions with S 1s → π* and S 1s → σ*(S-C) character were measured at the S 1s NEXAFS spectra. Poor charge delocalization was observed for as cast polymeric films at photon energies corresponding to the S 1s → π* transition, which may suggest a weak π-electronic coupling due to weak polymer crystallinity and chain stacking. Enhancement in the charge transfer process for photon energies close to the resonance maximum was observed for thermally annealed F8T2 and its blends. Atomic Force Microscopy (AFM) topography for as cast F8T2:PCBM shows a top position of PCBM units relative to the polymer, homogeneously distributed on the film surface. This configuration improves the charge delocalization through S 1s → π* molecular orbitals for the as cast blended film, suggesting a strong π-electronic coupling. A new rearrangement of F8T2:PCBM film was found after thermal annealing, leading to a more efficient electron transfer channel through σ* molecular orbitals.

  14. Longitudinal measurements of MRI-T2 in boys with Duchenne muscular dystrophy: effects of age and disease progression.

    Science.gov (United States)

    Willcocks, R J; Arpan, I A; Forbes, S C; Lott, D J; Senesac, C R; Senesac, E; Deol, J; Triplett, W T; Baligand, C; Daniels, M J; Sweeney, H L; Walter, G A; Vandenborne, K

    2014-05-01

    Duchenne muscular dystrophy (DMD) is characterized by an increased muscle damage and progressive replacement of muscle by noncontractile tissue. Both of these pathological changes can lengthen the MRI transverse proton relaxation time (T2). The current study measured longitudinal changes in T2 and its distribution in the lower leg of 16 boys with DMD (5-13years, 15 ambulatory) and 15 healthy controls (5-13years). These muscles were chosen to allow extended longitudinal monitoring, due to their slow progression compared with proximal muscles in DMD. In the soleus muscle of boys with DMD, T2 and the percentage of pixels with an elevated T2 (⩾2SD above control mean T2) increased significantly over 1year and 2years, while the width of the T2 histogram increased over 2years. Changes in soleus T2 variables were significantly greater in 9-13years old compared with 5-8years old boys with DMD. Significant correlations between the change in all soleus T2 variables over 2years and the change in functional measures over 2years were found. MRI measurement of muscle T2 in boys with DMD is sensitive to disease progression and shows promise as a clinical outcome measure.

  15. T2-signal of ulnar nerve branches at the wrist in guyon's canal syndrome.

    Directory of Open Access Journals (Sweden)

    Jennifer Kollmer

    Full Text Available OBJECTIVE: To evaluate T2-signal of high-resolution MRI in distal ulnar nerve branches at the wrist as diagnostic sign of guyon's-canal-syndrome (GCS. MATERIALS AND METHODS: 11 GCS patients confirmed by clinical/electrophysiological findings, and 20 wrists from 11 asymptomatic volunteers were prospectively included to undergo the following protocol: axial T2-weighted-fat-suppressed and T1-weighted-turbo-spin-echo-sequences (3T-MR-scanner, Magnetom/Verio/Siemens. Patients were examined in prone position with the arm extended and wrist placed in an 8-channel surface-array-coil. Nerve T2-signal was evaluated as contrast-to-noise-ratios (CNR from proximal-to-distal in ulnar nerve trunk, its superficial/sensory and deep/motor branch. Distal motor-nerve-conduction (distal-motor-latency (dml to first dorsal-interosseus (IOD I and abductor digiti minimi muscles was correlated with T2-signal. Approval by the institutional review-board and written informed consent was given by all participants. RESULTS: In GCS, mean nerve T2-signal was strongly increased within the deep/motor branch (11.7±4.8 vs.controls:-5.3±2.4;p = 0.001 but clearly less and not significantly increased in ulnar nerve trunk (6.8±6.4vs.-7.4±2.5;p = 0.07 and superficial/sensory branch (-2.1±4.9vs.-9.7±2.9;p = 0.08. Median nerve T2-signal did not differ between patients and controls (-9.8±2.5vs.-6.7±4.2;p = 0.45. T2-signal of deep/motor branch correlated strongly with motor-conduction-velocity to IOD I in non-linear fashion (R(2 = -0.8;p<0.001. ROC-analysis revealed increased nerve T2-signal of the deep/motor branch to be a sign of excellent diagnostic performance (area-under-the-curve 0.94, 95% CI: 0.85-1.00; specificity 90%, sensitivity 89.5%. CONCLUSIONS: Nerve T2-signal increase of distal ulnar nerve branches and in particular of the deep/motor branch is highly accurate for the diagnostic determination of GCS. Furthermore, for the first time it was found in nerve entrapment

  16. Intracellular lipid in papillary renal cell carcinoma (pRCC): T2 weighted (T2W) MRI and pathologic correlation

    Energy Technology Data Exchange (ETDEWEB)

    Schieda, Nicola; Van der Pol, Christian B.; Moosavi, Bardia; McInnes, Matthew D.F. [The Ottawa Hospital, The University of Ottawa, Department of Medical Imaging, Ottawa, Ontario (Canada); Mai, Kien T.; Flood, Trevor A. [The Ottawa Hospital, The University of Ottawa, Department of Anatomical Pathology, Ottawa, Ontario (Canada)

    2015-07-15

    To evaluate if pRCCs demonstrate intracellular lipid (i-lipid) at chemical-shift (CS) MRI, and assess T2W-MRI and pathologic characteristics. Sixty-two patients with a pRCC diagnosis underwent MRI over 11 years (IRB-approved). Two radiologists independently assessed for presence of i-lipid on CS-MRI and homogeneity on T2W-MRI. Inter-observer agreement was assessed via an intraclass correlation and results were compared using the Chi-square test. Discordant cases were reviewed to establish consensus. T2W SI-ratios (SI.tumor/SI.kidney) and CS-SI index were compared using independent t-tests and Spearman correlation. Two pathologists re-evaluated the histopathology. Nine of the 62 pRCCs (14.5 %) demonstrated i-lipid; agreement was moderate (ICC = 0.63). Pathology review depicted clear cells in four tumours and foamy histiocytes in five tumours. 25.8-35.4 % (ICC = 0.65) of tumours were homogeneous on T2W-MRI. No pRCC with i-lipid was considered homogeneous (p = 0.01-0.04). Overall, T2W SI-ratio and CS-SI index were 0.89 (±0.29) and -3.63 % (-7.27 to 11.42). pRCC with i-lipid had significantly higher T2W SI-ratio (p = 0.003). There was a correlation between the CS-SI index and T2W SI-ratio, (r = 0.44, p < 0.001). Intracellular lipid is uncommonly detected in pRCCs due to clear cell changes and foamy histiocytes. These tumours are associated with heterogeneously-increased SI in T2W-MRI. (orig.)

  17. Treat-to-target (T2T) recommendations for gout.

    Science.gov (United States)

    Kiltz, U; Smolen, J; Bardin, T; Cohen Solal, A; Dalbeth, N; Doherty, M; Engel, B; Flader, C; Kay, J; Matsuoka, M; Perez-Ruiz, F; da Rocha Castelar-Pinheiro, G; Saag, K; So, A; Vazquez Mellado, J; Weisman, M; Westhoff, T H; Yamanaka, H; Braun, J

    2017-04-01

    The treat-to-target (T2T) concept has been applied successfully in several inflammatory rheumatic diseases. Gout is a chronic disease with a high burden of pain and inflammation. Because the pathogenesis of gout is strongly related to serum urate levels, gout may be an ideal disease in which to apply a T2T approach. Our aim was to develop international T2T recommendations for patients with gout. A committee of experts with experience in gout agreed upon potential targets and outcomes, which was the basis for the systematic literature search. Eleven rheumatologists, one cardiologist, one nephrologist, one general practitioner and one patient met in October 2015 to develop T2T recommendations based on the available scientific evidence. Levels of evidence, strength of recommendations and levels of agreement were derived. Although no randomised trial was identified in which a comparison with standard treatment or an evaluation of a T2T approach had been performed in patients with gout, indirect evidence was provided to focus on targets such as normalisation of serum urate levels. The expert group developed four overarching principles and nine T2T recommendations. They considered dissolution of crystals and prevention of flares to be fundamental; patient education, ensuring adherence to medications and monitoring of serum urate levels were also considered to be of major importance. This is the first application of the T2T approach developed for gout. Since no publication reports a trial comparing treatment strategies for gout, highly credible overarching principles and level D expert recommendations were created and agreed upon. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  18. Purcell enhancement of fast-dephasing spontaneous emission from electron-hole droplets in high-Q silicon photonic crystal nanocavities

    Science.gov (United States)

    Sumikura, Hisashi; Kuramochi, Eiichi; Taniyama, Hideaki; Notomi, Masaya

    2016-11-01

    We have observed electron-hole droplet emission enhanced by silicon photonic crystal nanocavities with different Q values and simulated their Purcell effect using a semiclassical theory considering the temporal dephasing of the emission. When the photon loss rate of the nanocavities is smaller than the dephasing rate of the emission, the cavity-enhanced integrated photoluminescence (PL) intensity is unchanged by the cavity Q value. This is because the Purcell enhancement of the spontaneous emission rate is saturated in a high-Q region. In contrast, the peak intensity of the cavity-enhanced PL is proportional to the cavity Q value without saturation. These results suggest that a high-Q nanocavity is suitable for fabricating bright narrowband light emitting devices that concentrate the broadband emission energy of fast-dephasing emitters in a narrowband cavity resonance.

  19. T2 relaxometry of brain in myotonic dystrophy

    Energy Technology Data Exchange (ETDEWEB)

    Di Costanzo, A.; Bonavita, V.; Tedeschi, G. [Inst. of Neurological Sciences, 2. Univ. of Naples (Italy); Di Salle, F. [Dept. of Biomorphological and Functional Sciences, Univ. ' ' Federico II' ' , Naples (Italy); Santoro, L. [Dept. of Neurological Sciences, University ' ' Federico II' ' , Naples (Italy)

    2001-03-01

    We investigated the nature and extent of brain involvement in myotonic dystrophy (DM), examining possible T2 relaxation abnormalities in the brain of 20 patients with adult-onset DM and 20 sex- and age-matched normal controls. Brain MRI was performed at 0.5 T, and T2 values were calculated from signal intensity in two echoes. Regions of interest included: frontal, parietal, temporal, occipital and callosal (rostral and splenial) normal-appearing white matter; frontal, occipital, insular and hippocampal cortex; caudate nucleus, putamen, globus pallidus and thalamus. All white-matter and occipital and right frontal cortex regions showed a significantly longer T2 in the patients. Multiple regression analysis, including grey- and white-matter T2 as dependent variables, plus age at onset and at imaging, disease duration, muscular disability, brain atrophy and CTG trinucleotide repeats as independent variables, revealed that only white-matter T2 elongation and disease duration correlated positively. White-matter involvement in DM is more extensive than previously reported by MRI and neuropathological studies and seems to be progressive in the course of disease. (orig.)

  20. Value of black blood T2* cardiovascular magnetic resonance

    Directory of Open Access Journals (Sweden)

    Carpenter John Paul

    2011-03-01

    Full Text Available Abstract Purpose To assess whether black blood T2* cardiovascular magnetic resonance is superior to conventional white blood imaging of cardiac iron in patients with thalassaemia major (TM. Materials and methods We performed both conventional white blood and black blood T2* CMR sequences in 100 TM patients to determine intra and inter-observer variability and presence of artefacts. In 23 patients, 2 separate studies of both techniques were performed to assess interstudy reproducibility. Results Cardiac T2* values ranged from 4.5 to 43.8 ms. The mean T2* values were not different between black blood and white blood acquisitions (20.5 vs 21.6 ms, p = 0.26. Compared with the conventional white blood diastolic acquisition, the coefficient of variance of the black blood CMR technique was superior for intra-observer reproducibility (1.47% vs 4.23%, p Conclusions Black blood T2* CMR has superior reproducibility and reduced imaging artefacts for the assessment of cardiac iron, in comparison with the conventional white blood technique, which make it the preferred technique for clinical practice.

  1. Texture analysis of cartilage T2 maps: individuals with risk factors for OA have higher and more heterogeneous knee cartilage MR T2 compared to normal controls--data from the osteoarthritis initiative.

    Science.gov (United States)

    Joseph, Gabby B; Baum, Thomas; Carballido-Gamio, Julio; Nardo, Lorenzo; Virayavanich, Warapat; Alizai, Hamza; Lynch, John A; McCulloch, Charles E; Majumdar, Sharmila; Link, Thomas M

    2011-01-01

    The goals of this study were (i) to compare the prevalence of focal knee abnormalities, the mean cartilage T2 relaxation time, and the spatial distribution of cartilage magnetic resonance (MR) T2 relaxation times between subjects with and without risk factors for Osteoarthritis (OA), (ii) to determine the relationship between MR cartilage T2 parameters, age and cartilage morphology as determined with whole-organ magnetic resonance imaging scores (WORMS) and (iii) to assess the reproducibility of WORMS scoring and T2 relaxation time measurements including the mean and grey level co-occurrence matrix (GLCM) texture parameters. Subjects with risk factors for OA (n = 92) and healthy controls (n = 53) were randomly selected from the Osteoarthritis Initiative (OAI) incidence and control cohorts, respectively. The specific inclusion criteria for this study were (1) age range 45-55 years, (2) body mass index (BMI) of 19-27 kg/m2, (3) Western Ontario and McMaster University (WOMAC) pain score of zero and (4) Kellgren Lawrence (KL) score of zero at baseline. 3.0 Tesla MR images of the right knee were analyzed using morphological gradings of cartilage, bone marrow and menisci (WORMS) as well as compartment specific cartilage T2 mean and heterogeneity. Regression models adjusted for age, gender, and BMI were used to determine the difference in cartilage parameters between groups. While there was no significant difference in the prevalence of knee abnormalities (cartilage lesions, bone marrow lesions, meniscus lesions) between controls and subjects at risk for OA, T2 parameters (mean T2, GLCM contrast, and GLCM variance) were significantly elevated in those at risk for OA. Additionally, a positive significant association between cartilage WORMS score and cartilage T2 parameters was evident. Overall, this study demonstrated that subjects at risk for OA have both higher and more heterogeneous cartilage T2 values than controls, and that T2 parameters are associated with

  2. Metabolism of HT-2 Toxin and T-2 Toxin in Oats

    Science.gov (United States)

    Meng-Reiterer, Jacqueline; Bueschl, Christoph; Rechthaler, Justyna; Berthiller, Franz; Lemmens, Marc; Schuhmacher, Rainer

    2016-01-01

    The Fusarium mycotoxins HT-2 toxin (HT2) and T-2 toxin (T2) are frequent contaminants in oats. These toxins, but also their plant metabolites, may contribute to toxicological effects. This work describes the use of 13C-assisted liquid chromatography–high-resolution mass spectrometry for the first comprehensive study on the biotransformation of HT2 and T2 in oats. Using this approach, 16 HT2 and 17 T2 metabolites were annotated including novel glycosylated and hydroxylated forms of the toxins, hydrolysis products, and conjugates with acetic acid, putative malic acid, malonic acid, and ferulic acid. Further targeted quantitative analysis was performed to study toxin metabolism over time, as well as toxin and conjugate mobility within non-treated plant tissues. As a result, HT2-3-O-β-d-glucoside was identified as the major detoxification product of both parent toxins, which was rapidly formed (to an extent of 74% in HT2-treated and 48% in T2-treated oats within one day after treatment) and further metabolised. Mobility of the parent toxins appeared to be negligible, while HT2-3-O-β-d-glucoside was partly transported (up to approximately 4%) through panicle side branches and stem. Our findings demonstrate that the presented combination of untargeted and targeted analysis is well suited for the comprehensive elucidation of mycotoxin metabolism in plants. PMID:27929394

  3. Implementation of model predictive control for resistive wall mode stabilization on EXTRAP T2R

    Science.gov (United States)

    Setiadi, A. C.; Brunsell, P. R.; Frassinetti, L.

    2015-10-01

    A model predictive control (MPC) method for stabilization of the resistive wall mode (RWM) in the EXTRAP T2R reversed-field pinch is presented. The system identification technique is used to obtain a linearized empirical model of EXTRAP T2R. MPC employs the model for prediction and computes optimal control inputs that satisfy performance criterion. The use of a linearized form of the model allows for compact formulation of MPC, implemented on a millisecond timescale, that can be used for real-time control. The design allows the user to arbitrarily suppress any selected Fourier mode. The experimental results from EXTRAP T2R show that the designed and implemented MPC successfully stabilizes the RWM.

  4. Metal impurity fluxes and plasma-surface interactions in EXTRAP T2R

    Science.gov (United States)

    Bergsåker, H.; Menmuir, S.; Rachlew, E.; Brunsell, P. R.; Frassinetti, L.; Drake, J. R.

    2008-03-01

    The EXTRAP T2R is a large aspect ratio Reversed Field Pinch device. The main focus of interest for the experiments is the active feedback control of resistive wall modes [1]. With feedback it has been possible to prolong plasma discharges in T2R from about 20 ms to nearly 100 ms. In a series of experiments in T2R, in H- and D- plasmas with and without feedback, quantitative spectroscopy and passive collector probes have been used to study the flux of metal impurities. Time resolved spectroscopic measurements of Cr and Mo lines showed large metal release towards discharge termination without feedback. Discharge integrated fluxes of Cr, Fe, Ni and Mo were also measured with collector probes at wall position. Reasonable quantitative agreement was found between the spectroscopic and collector probe measurements. The roles of sputtering, thermal evaporation and arcing in impurity production are evaluated based on the composition of the measured impurity flux.

  5. Programming scheme based optimization of hybrid 4T-2R OxRAM NVSRAM

    Science.gov (United States)

    Majumdar, Swatilekha; Kingra, Sandeep Kaur; Suri, Manan

    2017-09-01

    In this paper, we present a novel single-cycle programming scheme for 4T-2R NVSRAM, exploiting pulse engineered input signals. OxRAM devices based on 3 nm thick bi-layer active switching oxide and 90 nm CMOS technology node were used for all simulations. The cell design is implemented for real-time non-volatility rather than last-bit, or power-down non-volatility. Detailed analysis of the proposed single-cycle, parallel RRAM device programming scheme is presented in comparison to the two-cycle sequential RRAM programming used for similar 4T-2R NVSRAM bit-cells. The proposed single-cycle programming scheme coupled with the 4T-2R architecture leads to several benefits such as- possibility of unconventional transistor sizing, 50% lower latency, 20% improvement in SNM and ∼20× reduced energy requirements, when compared against two-cycle programming approach.

  6. J-PARC Press Release: Electron neutrino oscillation detected at T2K

    CERN Document Server

    T2K Press Office

    2011-01-01

    Tsukuba, Japan, June 15, 2011. The T2K experiment, whose primary purpose is to study neutrino interactions at a large distance from their source, has detected 6 electron neutrino candidate events based on the data collected before March 11, 2011. For the first time, it was possible to observe an indication that muon neutrinos are able to transform into electron neutrinos over a distance of 295 km through the quantum mechanical phenomena of neutrino flavor oscillations.   The Super-Kamiokande detector, in Japan. © 2011, High Energy Accelerator Research Organization, KEK. The T2K experiment is searching for the neutrino oscillation phenomena, where particular types of neutrinos transform into other types of neutrinos. These observations help determine neutrino masses, as well elucidating the uncharted nature of neutrinos, such as the relationship among three neutrino generations (types). T2K aims at the world’s best sensitivity by detecting neutrinos with the Super-Kamiokande d...

  7. HOTELLING'S T2 CONTROL CHARTS BASED ON ROBUST ESTIMATORS

    Directory of Open Access Journals (Sweden)

    SERGIO YÁÑEZ

    2010-01-01

    Full Text Available Under the presence of multivariate outliers, in a Phase I analysis of historical set of data, the T 2 control chart based on the usual sample mean vector and sample variance covariance matrix performs poorly. Several alternative estimators have been proposed. Among them, estimators based on the minimum volume ellipsoid (MVE and the minimum covariance determinant (MCD are powerful in detecting a reasonable number of outliers. In this paper we propose a T 2 control chart using the biweight S estimators for the location and dispersion parameters when monitoring multivariate individual observations. Simulation studies show that this method outperforms the T 2 control chart based on MVE estimators for a small number of observations.

  8. T-2 Toxin Regulated Ganoderma lucidum Induced Cytokine Release

    Directory of Open Access Journals (Sweden)

    Kazem Ahmadi

    2008-01-01

    Full Text Available The water-soluble extract of Ganoderma lucidum (Reishi has been used as immunomodulator to stimulate spleen cells proliferation and cytokine expression. It has also been shown that at some level of exposure, T-2 toxin typically act as immunosuppressive agent and can increase disease susceptibility. The aim of this study was to investigate the effect of T-2 toxin on cytokine production by Ganoderma lucidum (G. lucidum treated-cells. Mice peritoneal macrophages and lymphoid T cells were prepared by usual manner and plated out at 1106 or 1104 cell/well respectively in RPMI 1640 supplemented with 10% FCS, 50 µg streptomycin and 50U penicillin. Cells were incubated with different concentrations of G. lucidum in the presence or absence of 1 ng mL-­1 T-2 toxin at 37°C and 5% CO2 for 48 h. Cell free medium was removed and used for cytokine assay by ELISA method. The results showed that T-2 toxin in the absence of G.lucidum enhanced IL-2, IFN-γ release compared with control group, but it reduced the production of other cytokines. G. lucidum enhanced the production of IL-1β TNF-α, IL-12, IL-2 and IFN-γ compared with control group, but reduced IL-4 and IL-10 release. T-2 toxin, up regulated the enhancement effect of G. lucidum on IFN-γ, IL-2 and TNF-α, but it down regulated its effect on the production of other cytokines. In conclution our results indicate that T-2 toxin at 1 ng mL-1 may augment the immunomodulating effects of G. lucidum on cytokine release.

  9. Command Center Training Tool (C2T2)

    Science.gov (United States)

    Jones, Phillip; Drucker, Nich; Mathews, Reejo; Stanton, Laura; Merkle, Ed

    2012-01-01

    This abstract presents the training approach taken to create a management-centered, experiential learning solution for the Virginia Port Authority's Port Command Center. The resultant tool, called the Command Center Training Tool (C2T2), follows a holistic approach integrated across the training management cycle and within a single environment. The approach allows a single training manager to progress from training design through execution and AAR. The approach starts with modeling the training organization, identifying the organizational elements and their individual and collective performance requirements, including organizational-specific performance scoring ontologies. Next, the developer specifies conditions, the problems, and constructs that compose exercises and drive experiential learning. These conditions are defined by incidents, which denote a single, multi-media datum, and scenarios, which are stories told by incidents. To these layered, modular components, previously developed meta-data is attached, including associated performance requirements. The components are then stored in a searchable library An event developer can create a training event by searching the library based on metadata and then selecting and loading the resultant modular pieces. This loading process brings into the training event all the previously associated task and teamwork material as well as AAR preparation materials. The approach includes tools within an integrated management environment that places these materials at the fingertips of the event facilitator such that, in real time, the facilitator can track training audience performance and resultantly modify the training event. The approach also supports the concentrated knowledge management requirements for rapid preparation of an extensive AAR. This approach supports the integrated training cycle and allows a management-based perspective and advanced tools, through which a complex, thorough training event can be developed.

  10. Modification of energy balance induced by the food contaminant T-2 toxin: a multimodal gut-to-brain connection.

    Science.gov (United States)

    Gaigé, Stéphanie; Djelloul, Mehdi; Tardivel, Catherine; Airault, Coraline; Félix, Bernadette; Jean, André; Lebrun, Bruno; Troadec, Jean-Denis; Dallaporta, Michel

    2014-03-01

    T-2 toxin is one of the most toxic Fusarium-derived trichothecenes found on cereals and constitutes a widespread contaminant of agricultural commodities as well as commercial foods. Low doses toxicity is characterized by reduced weight gain. To date, the mechanisms by which this mycotoxin profoundly modifies feeding behavior remain poorly understood and more broadly the effects of T-2 toxin on the central nervous system (CNS) have received limited attention. Through an extensive characterization of sickness-like behavior induced by T-2 toxin, we showed that its per os (p.o.) administration affects not only feeding behavior but also energy expenditure, glycaemia, body temperature and locomotor activity. Using c-Fos expression mapping, we identified the neuronal structures activated in response to T-2 toxin and observed that the pattern of neuronal populations activated by this toxin resembled that induced by inflammatory signals. Interestingly, part of neuronal pathways activated by the toxin were NUCB-2/nesfatin-1 expressing neurons. Unexpectedly, while T-2 toxin induced a strong peripheral inflammation, the brain exhibited limited inflammatory response at a time point when anorexia was ongoing. Unilateral vagotomy partly reduced T-2 toxin-induced brainstem neuronal activation. On the other hand, intracerebroventricular (icv) T-2 toxin injection resulted in a rapid (food intake. Thus, we hypothesized that T-2 toxin could signal to the brain through neuronal and/or humoral pathways. The present work provides the first demonstration that T-2 toxin modifies feeding behavior by interfering with central neuronal networks devoted to central energy balance. Our results, with a particular attention to peripheral inflammation, strongly suggest that inflammatory mediators partake in the T-2 toxin-induced anorexia and other symptoms. In view of the broad human and breeding animal exposure to T-2 toxin, this new mechanism may lead to reconsider the impact of the consumption of

  11. Metabolism of the Fusarium Mycotoxins T-2 Toxin and HT-2 Toxin in Wheat.

    Science.gov (United States)

    Nathanail, Alexis V; Varga, Elisabeth; Meng-Reiterer, Jacqueline; Bueschl, Christoph; Michlmayr, Herbert; Malachova, Alexandra; Fruhmann, Philipp; Jestoi, Marika; Peltonen, Kimmo; Adam, Gerhard; Lemmens, Marc; Schuhmacher, Rainer; Berthiller, Franz

    2015-09-01

    To investigate the metabolic fate of HT-2 toxin (HT2) and T-2 toxin (T2) in wheat (Triticum aestivum L.), an untargeted metabolomics study utilizing stable isotopic labeling and liquid chromatography-high resolution mass spectrometry was performed. In total, 11 HT2 and 12 T2 derived in planta biotransformation products were annotated putatively. In addition to previously reported mono- and diglucosylated forms of HT2, evidence for the formation of HT2-malonyl-glucoside and feruloyl-T2, as well as acetylation and deacetylation products in wheat was obtained for the first time. To monitor the kinetics of metabolite formation, a time course experiment was conducted involving the Fusarium head blight susceptible variety Remus and the resistant cultivar CM-82036. Biotransformation reactions were observed already at the earliest tested time point (6 h after treatment), and formed metabolites showed different kinetic profiles. After ripening, less than 15% of the toxins added to the plants were determined to be unmetabolized.

  12. Peripheral nerve MRI: precision and reproducibility of T2*-derived measurements at 3.0-T. A feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Tagliafico, Alberto [University of Genoa, Institute of Anatomy, Department of Experimental Medicine, Genoa (Italy); Bignotti, Bianca; Martinoli, Carlo [University of Genoa, Radiology Department, Genoa, Genova (Italy); Tagliafico, Giulio [CNR-IMATI, Consiglio Nazionale delle Ricerche, Istituto di Matematica Applicata e Tecnologie Informatiche, Genova (Italy)

    2015-05-01

    To prospectively evaluate the precision and reproducibility of T2*-derived measurements of the peripheral nerves. The study was approved by the local ethics committee and written informed consent was obtained. Bilateral upper and lower limb MRI examination was performed in 40 healthy subjects on a 3.0-T scanner. MRI protocol included T1-turbo spin-echo, T2-turbo spin-echo with fat suppression, and multiecho gradient recalled echo. Measurements of T2* times on T2* maps at different anatomical levels were performed. Three authors measured independently and in different sessions at baseline and after 4 weeks. Non-parametric tests and Bland-Altman statistics were used. Minimum and maximum percentage variability were 10 % and 19 % for T2* (84-91 % of reproducibility). Maximum values of minimum detectable differences between limbs was 16 % (with 95 % CI: 2-37). Intra- and inter-observer agreement of the three radiologists for T2* was considered good. Evaluating the combined influence of the observer and of the repeated measurements the reproducibility was 87-98 %. T2* measurement of the peripheral nerves is precise and reproducible. The healthy contralateral side can be used as an internal control. Variations in T2* values up to 16 % have to be considered. (orig.)

  13. Role of T2 inflammation biomarkers in severe asthma

    NARCIS (Netherlands)

    Parulekar, Amit D.; Diamant, Zuzana; Hanania, Nicola A.

    Purpose of reviewSevere asthma is a heterogeneous syndrome. Classification of asthma into phenotypes and endotypes can improve understanding and treatment of the disease. Identification and utilization of biomarkers, particularly those linked to T2 inflammation, can help group patients into

  14. Anti-neutrino oscillations with T2K

    CERN Document Server

    Salzgeber, M Ravonel

    2015-01-01

    T2K is a long-baseline neutrino oscillation experiment, in which a muon neutrino beam is produced at J-PARC and detected 295 km away at the Super-Kamiokande detector. The T2K experiment observed electron-neutrino appearance in 2012. This observation enables T2K to explore CP violation in the lepton sector by comparing electron-neutrino appearance and electron-antineutrino appearance. Indeed, the number of observed electron neutrino events up to 2012 is, though within statistical fluctuation, larger than the expectation, which suggests maximal CP violation. Since 2013, T2K has been accumulating data with a muon antineutrino beam. If the suggested maximal CP violation is true, electron-antineutrino appearance would be suppressed. The signal is further suppressed by the smaller cross section for antineutrinos compared to neutrinos. Hence the observation of electron-antineutrino appearance is an important next step. Furthermore, the CPT theorem imposes that the muon disappearance rate must be the same for muon ne...

  15. Changes in T2-weighted MRI of supinator muscle, pronator teres muscle, and extensor indicis muscle with manual muscle testing

    Science.gov (United States)

    Yoshida, Kazuya; Akiyama, Sumikazu; Takamori, Masayoshi; Otsuka, D. Eng, Hiroshi; Seo, Yoshiteru

    2017-01-01

    [Purpose] In order to detect muscle activity with manual muscle testing, T2-weighted magnetic resonance (T2w-MR) images were detected by a 0.2 T compact MRI system. [Subjects and Methods] The subjects were 3 adult males. Transverse T2-weighted multi-slice spin-echo images of the left forearm were measured by a 39 ms echo-time with a 2,000 ms repetition time, a 9.5 mm slice thickness, 1 accumulation and a total image acquisition time of 4 min 16 s. First, T2w-MR images in the resting condition were measured. Then, manipulative isometric contraction exercise (5 sec duration) to the supinator muscle, the pronator teres muscle or the extensor indicis muscle was performed using Borg’s rating of perceived exertion (RPE) scale of 15–17. The T2w-MR images were measured immediately after the exercise. [Results] T2w-MR image intensities increased significantly in the supinator muscle, the pronator teres muscle and the extensor indicis muscle after the exercise. However, the image intensities in the rest of the muscle did not change. [Conclusion] Using T2w-MR images, we could detect muscle activity in a deep muscle, the supinator muscle, and a small muscle, the extensor indicis muscle. These results also support the reliability of the manual muscle testing method. PMID:28356621

  16. Toxicokinetic study and absolute oral bioavailability of deoxynivalenol, T-2 toxin and zearalenone in broiler chickens.

    Science.gov (United States)

    Osselaere, Ann; Devreese, Mathias; Goossens, Joline; Vandenbroucke, Virginie; De Baere, Siegrid; De Backer, Patrick; Croubels, Siska

    2013-01-01

    Mycotoxins lead to economic losses in animal production. A way to counteract mycotoxicosis is the use of detoxifiers. The European Food Safety Authority stated that the efficacy of detoxifiers should be investigated based on toxicokinetic studies. Little information is available on the absolute oral bioavailability and the toxicokinetic parameters of deoxynivalenol, T-2 and zearalenone in broilers. Toxins were administered intravenously and orally in a two-way cross-over design. For deoxynivalenol a bolus of 0.75mg/kg BW was administered, for T-2 toxin 0.02mg/kg BW and for zearalenone 0.3mg/kg BW. Blood was collected at several time points. Plasma levels of the mycotoxins and their metabolite(s) were quantified using LC-MS/MS methods and toxicokinetic parameters were analyzed. Deoxynivalenol has a low absolute oral bioavailability (19.3%). For zearalenone and T-2 no plasma levels above the limit of quantification were observed after an oral bolus. Volumes of distribution were recorded, i.e. 4.99, 0.14 and 22.26L/kg for deoxynivalenol, T-2 toxin and zearalenone, respectively. Total body clearance was 0.12, 0.03 and 0.48L/minkg for deoxynivalenol, T-2 toxin and zearalenone, respectively. After IV administration, T-2 toxin had the shortest elimination half-life (3.9min), followed by deoxynivalenol (27.9min) and zearalenone (31.8min). Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Optical dephasing by uncorrelated phonon scattering to librations. An optical and picosecond photon echo study of a photosite of pentacene in benzoic acid

    NARCIS (Netherlands)

    Molenkamp, L.W.; Wiersma, Douwe A.

    1984-01-01

    We report results of an optical and picosecond photon echo study on the zero-phonon line of photosite I of pentacene in benzoic acid. The results show that optical dephasing in this system proceeds via uncorrelated phonon scattering processes from the ground and optically excited state to singly exc

  18. Non-markovian model of photon-assisted dephasing by electron-phonon interactions in a coupled quantum-dot-cavity system

    DEFF Research Database (Denmark)

    Nielsen, Per Kær; Nielsen, Torben Roland; Lodahl, Peter;

    2010-01-01

    We investigate the influence of electron-phonon interactions on the dynamical properties of a quantum-dot-cavity QED system. We show that non-Markovian effects in the phonon reservoir lead to strong changes in the dynamics, arising from photon-assisted dephasing processes, not present in Markovian...

  19. The effect of dephasing on edge state transport through p-n junctions in HgTe/CdTe quantum wells.

    Science.gov (United States)

    Zhang, Ying-Tao; Song, Juntao; Sun, Qing-Feng

    2014-02-26

    Using the Landauer-Büttiker formula, we study the effect of dephasing on the transport properties of the HgTe/CdTe p-n junction. It is found that in the HgTe/CdTe p-n junction the topologically protected gapless helical edge states manifest a quantized 2e²/h plateau robust against dephasing, in sharp contrast to the case for the normal HgTe/CdTe quantum well. This robustness of the transport properties of the edge states against dephasing should be attributed to the special construction of the HgTe/CdTe p-n junction, which limits the gapless helical edge states to a very narrow region and thus weakens the influence of the dephasing on the gapless edge states to a large extent. Our results demonstrate that the p-n junction could be a substitute device for use in experimentally observing the robust edge states and quantized plateau. Finally, we present a feasible scheme based on current experimental methods.

  20. 臂丛神经磁共振IDEAL T2WI 和CUBE Flex T2WI 成像%Imaging of the Brachial Plexus with IDEAL and CUBE FlexT2-Weighted Imaging

    Institute of Scientific and Technical Information of China (English)

    郭勇; 林伟; 钱明珠; 黄敏华; 孙楠; 吕剑; 盛浩

    2011-01-01

    Purpose To compare the methods ofiterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL), Cube Flex methods with fat-saturated T2-weighted-imaging (T2WI), fast spin-echo (FSE) and short-TI inversion recovery (STIR) imaging of the brachial plexus. Materials and Methods Images were acquired at 3.0T scanner in 14 volunteers. Fat-saturated FSE T2WI and STIR images were compared with IDEAL T2WI images and Cube Flex-T2WI images. Results IDEAL T2WI and Cube Flex-T2WI demonstrated similar fat suppression quality compared with STIR (P > 0.05) and better than fat-saturated FSE T2WI (P < 0.05). Signal noise ratio and contrast noise ratio of brachial plexus showed significant difference in the following sequences: IDEAL T2WI > Cube Flex T2WI > FSE T2WI > STIR (P < 0.05). Images of IDEAL T2WI and Cube Flex T2WI reconstructed with different slice thickness could clearly demonstrate brachial plexus. Conclusion IDEAL T2WI and Cube Flex T2WI can provide high signal noise ratio images with reliable and uniform fat suppression for clearly imaging the brachial plexus.%目的 比较磁共振脂肪抑制FSE T2WI 、STIR T2WI 、IDEAL T2WI 及CUBE Flex T2WI 4 种方法显示正常臂丛神经的优劣.资料与方法对14 例自愿者行臂丛神经MRI 脂肪抑制FSE T2WI 、STIR T2WI 、IDEAL T2WI 及CUBE Flex T2WI 检查.对图像脂肪抑制质量进行肉眼分级评估,并测量信噪比和对比噪声比.结果 IDEAL T2WI 、CUBE Flex T2WI 脂肪抑制质量明显优于FSE T2WI(P <0.05),与STIR T2WI 相比差异无统计学意义(P >0.05).信噪比、对比噪声比均值比较各组间差异均有统计学意义(P <0.05),IDEAL T2WI >CUBE Flex T2WI >FSE T2WI >STIR T2WI.IDEAL T2WI 和CUBE Flex T2WI 图像均可选择不同厚度重建、斜面重建等,从而可显示臂丛神经各段.结论 IDEAL T2WI 、CUBE Flex T2WI 能提供均匀稳定的脂肪抑制,图像信噪比高,可清晰显示臂丛神经.

  1. T2-weighted liver MRI using the multiVane technique at 3T: Comparison with conventional T2-weighted MRI

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Kyung A [Dept. of Radiology, Myongji Hospital, Seonam University College of Medicine, Goyang (Korea, Republic of); Kim, Young Kon; Jeong, Woo Kyoung; Choi, Dong Il; Lee, Won Jae [Dept. of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Kim, Eun Ju [Philips Healthcare Korea, Philips, Seoul (Korea, Republic of); Jung, Sin Ho; Baek, Sun Young [Biostatistics and Clinical Epidemiology Center, Samsung Medical Center, Seoul (Korea, Republic of)

    2015-10-15

    To assess the value of applying MultiVane to liver T2-weighted imaging (T2WI) compared with conventional T2WIs with emphasis on detection of focal liver lesions. Seventy-eight patients (43 men and 35 women) with 86 hepatic lesions and 20 pancreatico-biliary diseases underwent MRI including T2WIs acquired using breath-hold (BH), respiratory-triggered (RT), and MultiVane technique at 3T. Two reviewers evaluated each T2WI with respect to artefacts, organ sharpness, and conspicuity of intrahepatic vessels, hilar duct, and main lesion using five-point scales, and made pairwise comparisons between T2WI sequences for these categories. Diagnostic accuracy (Az) and sensitivity for hepatic lesion detection were evaluated using alternative free-response receiver operating characteristic analysis. MultiVane T2WI was significantly better than BH-T2WI or RT-T2WI for organ sharpness and conspicuity of intrahepatic vessels and main lesion in both separate reviews and pairwise comparisons (p < 0.001). With regard to motion artefacts, MultiVane T2WI or BH-T2WI was better than RT-T2WI (p < 0.001). Conspicuity of hilar duct was better with BH-T2WI than with MultiVane T2WI (p = 0.030) or RT-T2WI (p < 0.001). For detection of 86 hepatic lesions, sensitivity (mean, 97.7%) of MultiVane T2WI was significantly higher than that of BH-T2WI (mean, 89.5%) (p = 0.008) or RT-T2WI (mean, 84.9%) (p = 0.001). Applying the MultiVane technique to T2WI of the liver is a promising approach to improving image quality that results in increased detection of focal liver lesions compared with conventional T2WI.

  2. In vivo deformation of thin cartilage layers: Feasibility and applicability of T2* mapping.

    Science.gov (United States)

    Van Ginckel, Ans; Witvrouw, Erik E

    2016-05-01

    The objectives of this study were as follows: (i) to assess segmentation consistency and scan precision of T2* mapping of human tibio-talar cartilage, and (ii) to monitor changes in T2* relaxation times of ankle cartilage immediately following a clinically relevant in vivo exercise and during recovery. Using multi-echo gradient recalled echo sequences, averaged T2* values were calculated for tibio-talar cartilage layers in 10 healthy volunteers. Segmentation consistency and scan precision were determined from two repeated segmentations and two repeated acquisitions with repositioning, respectively. Subsequently, acute in vivo cartilage loading responses were monitored by calculating averaged tibio-talar T2* values at rest, immediately after (i.e., deformation) and at 15 min (i.e., recovery) following a 30-repetition knee bending exercise. Precision errors attained 4-6% with excellent segmentation consistency point estimates (i.e., intra-rater ICC of 0.95) and acceptable limits of confidence. At deformation, T2* values were increased in both layers [+16.1 (10.7)%, p = 0.004 and +17.3 (15.3)%, p = 0.023, for the talus and tibia, respectively] whereas during recovery no significant changes could be established when comparing to baseline [talar cartilage: +5.2 (8.2)%, p = 0.26 and tibial cartilage: +6.6 (10.4)%, p = 0.23]. T2* mapping is a viable method to monitor deformational behavior in thin cartilage layers such as ankle cartilage. Longitudinal changes in T2* can be reliably appraised and require at least 4-6% differences to ascertain statistical significance. The ability to detect considerable change even after non-strenuous loading events, endorses T2* mapping as an innovative method to evaluate the effects of therapeutic exercise on thin cartilage layers. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:771-778, 2016.

  3. Liver, bone marrow, pancreas and pituitary gland iron overload in young and adult thalassemic patients: a T2 relaxometry study

    Energy Technology Data Exchange (ETDEWEB)

    Argyropoulou, Maria I.; Astrakas, Loukas; Metafratzi, Zafiria; Efremidis, Stavros C. [University of Ioannina, Department of Radiology, Medical School, Ioannina (Greece); Kiortsis, Dimitrios N. [University of Ioannina, Laboratory of Physiology, Medical School, Ioannina (Greece); Chalissos, Nikolaos [University of Ioannina, Department of Radiology, Medical School, Ioannina (Greece); University of Ioannina, Laboratory of Physiology, Medical School, Ioannina (Greece)

    2007-12-15

    Thirty-seven patients with {beta}-thalassemia major, including 14 adolescents (15.2 {+-} 3.0 years) and 23 adults (26.4 {+-} 6.9 years), were studied. T2 relaxation time (T2) of the liver, bone marrow, pancreas and pituitary gland was measured in a 1.5-Tesla magnetic resonance (MR) imager, using a multiecho spin-echo sequence (TR/TE 2,000/20, 40, 60, 80, 100, 120, 140, 160 ms). Pituitary gland height was evaluated in a midline sagittal scan of a spin-echo sequence (TR/TE, 500/20 ms). The T2 of the pituitary gland was higher in adolescents (59.4 {+-} 15 ms) than in adults (45.3 {+-} 10.4 ms), P < 0.05. The T2 of the pancreas was lower in adolescents (43.6 {+-} 10.3 ms) than in adults (54.4 {+-} 10.4 ms). No difference among groups was found in the T2 of the liver and bone marrow. There was no significant correlation of the T2 among the liver, pancreas, pituitary gland and bone marrow. There was no significant correlation between serum ferritin and T2 of the liver, pancreas and bone marrow. Pituitary T2 showed a significant correlation with pituitary gland height (adolescents: R = 0.63, adults: R = 0.62, P < 0.05) and serum ferritin (adolescents: R = -0.60, adults: R = -0.50, P < 0.05). In conclusion, iron overload evaluated by T2 is organ specific. After adolescence, age-related T2 changes are predominantly associated with pituitary siderosis and fatty degeneration of the pancreas. Pituitary size decreases with progressing siderosis. (orig.)

  4. Correlation between Heart, Liver and Pancreas Hemosiderosis Measured by MRI T2* among Thalassemia Major Patients from Iran.

    Science.gov (United States)

    Azarkeivan, Azita; Hashemieh, Mozhgan; Shirkavand, Afshan; Sheibani, Kourosh

    2016-02-01

    Major thalassemia patients need lifelong transfusions. The consequence of these repeated transfusions is iron accumulation in different organs. The main aim of the present study was to investigate the correlation between heart, liver and pancreas hemosiderosis in thalassemic patients from Iran. This cross-sectional study was conducted on 164 major thalassemia patients at Zafar Adult Thalassemia Center, a referral thalassemia center in Tehran, Iran, from May to November 2014.  All patients were on regular blood transfusion at 2-4 week intervals to keep their hemoglobin at a level of 7-9 gr/dL before each transfusion. Demographic data were gathered from patients' history. MRI T2* of liver, heart and pancreas were performed for all patients. There were a moderate correlation between pancreatic T2* and cardiac T2* relaxation times (r = 0.42, P pancreas and liver (r = 0.41, P pancreas and liver T2* relaxation times indicate that relying on liver MRI T2* to predict the exact condition of pancreas or heart iron overload might not be a reliable approach in thalassemia major patients. Our findings suggest the advantage of using pancreas and heart MRI T2* as a non-invasive method for estimation of iron overload instead of relying on liver MRI T2*.

  5. Sclerosing epithelioid fiberosarcoma: short T2 on MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, D.R.; Gilbert, T.J. [Department of Radiology, University of Minnesota Hospital and Clincis, 420 Delaware Street South East/Box 292, Minneapolis, MN 55455 (United States); Ramsamooj, R. [Department of Lab Medicine and Pathology, Division of Surgical Pathology, University of Minnesota Hospital and Clinics, Minneapolis, MN (United States)

    1997-10-01

    A case of sclerosing epithelioid fibrosarcoma and its appearance on MRI is presented. The tumor showed a zonal architecture on MRI with a large central core of very low signal intensity and a peripheral rim of intermediate to high signal intensity on T1- and T2-weighted spin echo pulse sequences. The core showed decreased cellularity with dense collagen deposition on histologic examination, and the peripheral zone increased cellularity with increased nuclear atypia. The presence of a prominent region of very low signal intensity on T1- and T2-weighted images can be seen with neural tumors, giant cell tumor of the tendon sheath, aggressive fibromatosis, and, in rare instances, with soft tissue sarcomas rich in collagen. (orig.) With 2 figs., 6 refs.

  6. 养殖对虾T-2毒素蓄积危害研究现状%Research Status of T-2 toxin Accumulation Harm in Cultured Prawn

    Institute of Scientific and Technical Information of China (English)

    王雅玲; 励建荣; 孙力军

    2012-01-01

    The feed has been seriously contaminated by T-2 toxin in China. If cultured aquatic animals have taken in the feed contaminated by low dose T-2 toxin for a long time, the T-2 toxin could remain in muscle and result in growing slowly, this could pose a potential food safety risk and decline in the quality of muscle. This article summarizes the current situation about T-2 toxin in prawn feed around the world, and states the potential hazards and its evaluation indicator. The result is important for further development about mycotoxin exposure risk evaluation of aquatic products and formulation of dietary exposure standard.%我国饲料中T-2毒素污染严重,养殖水产动物长期摄入饲料中普遍污染的低剂量T-2毒素,可导致其肌肉残留和生长缓慢,肌肉品质下降,并存在食品安全风险.本文概述了国内外对虾饲料中T-2毒素污染现状,阐明对虾的潜在危害及其评价指标的研究现状,这对进一步开展水产品真菌毒素暴露风险评估和制定膳食接触标准具有重要意义.

  7. Detection of T-2 Toxin by an Improved Radioimmunoassay

    Science.gov (United States)

    1983-02-01

    average affinity constant of the antibody (Kin) was 1.75 x 1010 liters/mol. The sensitivity was 1 ng per assay or 10 ng/ml. Among the other trichothecenes ... human intoxication. The ingestion of food prod- ity was counted in a Searle 6880 liquid scintillation ucts contaminated with toxins from certain fun...the antibody that to trichothecene ingestion, specifically T-2, have resulted in the binding of 50% of the radioactivity in been reported in certain

  8. Neutrino oscillation physics potential of the T2K experiment

    Science.gov (United States)

    T2K Collaboration; Abe, K.; Adam, J.; Aihara, H.; Akiri, T.; Andreopoulos, C.; Aoki, S.; Ariga, A.; Assylbekov, S.; Autiero, D.; Barbi, M.; Barker, G. J.; Barr, G.; Bartet-Friburg, P.; Bass, M.; Batkiewicz, M.; Bay, F.; Berardi, V.; Berger, B. E.; Berkman, S.; Bhadra, S.; Blaszczyk, F. d. M.; Blondel, A.; Bojechko, C.; Bordoni, S.; Boyd, S. B.; Brailsford, D.; Bravar, A.; Bronner, C.; Buchanan, N.; Calland, R. G.; Caravaca Rodríguez, J.; Cartwright, S. L.; Castillo, R.; Catanesi, M. G.; Cervera, A.; Cherdack, D.; Christodoulou, G.; Clifton, A.; Coleman, J.; Coleman, S. J.; Collazuol, G.; Connolly, K.; Cremonesi, L.; Dabrowska, A.; Danko, I.; Das, R.; Davis, S.; de Perio, P.; de Rosa, G.; Dealtry, T.; Dennis, S. R.; Densham, C.; Dewhurst, D.; Di Lodovico, F.; Di Luise, S.; Drapier, O.; Duboyski, T.; Duffy, K.; Dumarchez, J.; Dytman, S.; Dziewiecki, M.; Emery-Schrenk, S.; Ereditato, A.; Escudero, L.; Feusels, T.; Finch, A. J.; Fiorentini, G. A.; Friend, M.; Fujii, Y.; Fukuda, Y.; Furmanski, A. P.; Galymov, V.; Garcia, A.; Giffin, S.; Giganti, C.; Gilje, K.; Goeldi, D.; Golan, T.; Gonin, M.; Grant, N.; Gudin, D.; Hadley, D. R.; Haegel, L.; Haesler, A.; Haigh, M. D.; Hamilton, P.; Hansen, D.; Hara, T.; Hartz, M.; Hasegawa, T.; Hastings, N. C.; Hayashino, T.; Hayato, Y.; Hearty, C.; Helmer, R. L.; Hierholzer, M.; Hignight, J.; Hillairet, A.; Himmel, A.; Hiraki, T.; Hirota, S.; Holeczek, J.; Horikawa, S.; Huang, K.; Ichikawa, A. K.; Ieki, K.; Ieva, M.; Ikeda, M.; Imber, J.; Insler, J.; Irvine, T. J.; Ishida, T.; Ishii, T.; Iwai, E.; Iwamoto, K.; Iyogi, K.; Izmaylov, A.; Jacob, A.; Jamieson, B.; Johnson, R. A.; Johnson, S.; Jo, J. H.; Jonsson, P.; Jung, C. K.; Kabirnezhad, M.; Kaboth, A. C.; Kajita, T.; Kakuno, H.; Kameda, J.; Kanazawa, Y.; Karlen, D.; Karpikov, I.; Katori, T.; Kearns, E.; Khabibullin, M.; Khotjantsev, A.; Kielczewska, D.; Kikawa, T.; Kilinski, A.; Kim, J.; King, S.; Kisiel, J.; Kitching, P.; Kobayashi, T.; Koch, L.; Koga, T.; Kolaceke, A.; Konaka, A.; Kormos, L. L.; Korzenev, A.; Koshio, Y.; Kropp, W.; Kubo, H.; Kudenko, Y.; Kurjata, R.; Kutter, T.; Lagoda, J.; Laihem, K.; Lamont, I.; Larkin, E.; Laveder, M.; Lawe, M.; Lazos, M.; Lindner, T.; Lister, C.; Litchfield, R. P.; Longhin, A.; Lopez, J. P.; Ludovici, L.; Magaletti, L.; Mahn, K.; Malek, M.; Manly, S.; Marino, A. D.; Marteau, J.; Martin, J. F.; Martins, P.; Martynenko, S.; Maruyama, T.; Matveev, V.; Mavrokoridis, K.; Mazzucato, E.; McCarthy, M.; McCauley, N.; McFarland, K. S.; McGrew, C.; Mefodiev, A.; Metelko, C.; Mezzetto, M.; Mijakowski, P.; Miller, C. A.; Minamino, A.; Mineev, O.; Missert, A.; Miura, M.; Moriyama, S.; Mueller, Th. A.; Murakami, A.; Murdoch, M.; Murphy, S.; Myslik, J.; Nakadaira, T.; Nakahata, M.; Nakamura, K. G.; Nakamura, K.; Nakayama, S.; Nakaya, T.; Nakayoshi, K.; Nantais, C.; Nielsen, C.; Nirkko, M.; Nishikawa, K.; Nishimura, Y.; Nowak, J.; O'Keeffe, H. M.; Ohta, R.; Okumura, K.; Okusawa, T.; Oryszczak, W.; Oser, S. M.; Ovsyannikova, T.; Owen, R. A.; Oyama, Y.; Palladino, V.; Palomino, J. L.; Paolone, V.; Payne, D.; Perevozchikov, O.; Perkin, J. D.; Petrov, Y.; Pickard, L.; Pinzon Guerra, E. S.; Pistillo, C.; Plonski, P.; Poplawska, E.; Popov, B.; Posiadala-Zezula, M.; Poutissou, J.-M.; Poutissou, R.; Przewlocki, P.; Quilain, B.; Radicioni, E.; Ratoff, P. N.; Ravonel, M.; Rayner, M. A. M.; Redij, A.; Reeves, M.; Reinherz-Aronis, E.; Riccio, C.; Rodrigues, P. A.; Rojas, P.; Rondio, E.; Roth, S.; Rubbia, A.; Ruterbories, D.; Sacco, R.; Sakashita, K.; Sánchez, F.; Sato, F.; Scantamburlo, E.; Scholberg, K.; Schoppmann, S.; Schwehr, J.; Scott, M.; Seiya, Y.; Sekiguchi, T.; Sekiya, H.; Sgalaberna, D.; Shah, R.; Shaker, F.; Shiozawa, M.; Short, S.; Shustrov, Y.; Sinclair, P.; Smith, B.; Smy, M.; Sobczyk, J. T.; Sobel, H.; Sorel, M.; Southwell, L.; Stamoulis, P.; Steinmann, J.; Still, B.; Suda, Y.; Suzuki, A.; Suzuki, K.; Suzuki, S. Y.; Suzuki, Y.; Tacik, R.; Tada, M.; Takahashi, S.; Takeda, A.; Takeuchi, Y.; Tanaka, H. K.; Tanaka, H. A.; Tanaka, M. M.; Terhorst, D.; Terri, R.; Thompson, L. F.; Thorley, A.; Tobayama, S.; Toki, W.; Tomura, T.; Totsuka, Y.; Touramanis, C.; Tsukamoto, T.; Tzanov, M.; Uchida, Y.; Vacheret, A.; Vagins, M.; Vasseur, G.; Wachala, T.; Waldron, A. V.; Wakamatsu, K.; Walter, C. W.; Wark, D.; Warzycha, W.; Wascko, M. O.; Weber, A.; Wendell, R.; Wilkes, R. J.; Wilking, M. J.; Wilkinson, C.; Williamson, Z.; Wilson, J. R.; Wilson, R. J.; Wongjirad, T.; Yamada, Y.; Yamamoto, K.; Yanagisawa, C.; Yano, T.; Yen, S.; Yershov, N.; Yokoyama, M.; Yoshida, K.; Yuan, T.; Yu, M.; Zalewska, A.; Zalipska, J.; Zambelli, L.; Zaremba, K.; Ziembicki, M.; Zimmerman, E. D.; Zito, M.; Żmuda, J.

    2015-04-01

    The observation of the recent electron neutrino appearance in a muon neutrino beam and the high-precision measurement of the mixing angle θ _{13} have led to a re-evaluation of the physics potential of the T2K long-baseline neutrino oscillation experiment. Sensitivities are explored for CP violation in neutrinos, non-maximal sin ^22θ _{23}, the octant of θ _{23}, and the mass hierarchy, in addition to the measurements of δ _{CP}, sin ^2θ _{23}, and Δ m^2_{32}, for various combinations of ν-mode and bar {ν }-mode data-taking. With an exposure of 7.8× 10^{21} protons-on-target, T2K can achieve 1σ resolution of 0.050 (0.054) on sin ^2θ _{23} and 0.040 (0.045)× 10^{-3} {eV}^2 on Δ m^2_{32} for 100% (50%) neutrino beam mode running assuming sin ^2θ _{23}=0.5 and Δ m^2_{32} = 2.4× 10^{-3} eV^2. T2K will have sensitivity to the CP-violating phase δ _{CP} at 90% C.L. or better over a significant range. For example, if sin ^22θ _{23} is maximal (i.e. θ _{23}=45°) the range is -115° < δ _{CP}< -60° for normal hierarchy and +50° < δ _{CP}< +130° for inverted hierarchy. When T2K data is combined with data from the NOνA experiment, the region of oscillation parameter space where there is sensitivity to observe a non-zero δ _{CP} is substantially increased compared to if each experiment is analyzed alone.

  9. UTE-T2(⁎) Analysis of Diseased and Healthy Achilles Tendons and Correlation with Clinical Score: An In Vivo Preliminary Study.

    Science.gov (United States)

    Qiao, Yang; Tao, Hong-Yue; Ma, Kui; Wu, Zi-Ying; Qu, Jian-Xun; Chen, Shuang

    2017-01-01

    Objective. To compare T2(⁎) value of healthy and diseased Achilles tendons (AT) with a recently introduced three-dimensional ultrashort echo time (3D-UTE) sequence and analyze the correlation between T2(⁎) value and clinical scores. Methods. Ten patients with symptomatic Achilles tendon and ten healthy volunteers were investigated with 3D-UTE sequence on a 3T magnetic resonance (MR) scanner. T2(⁎) values of four regions in Achilles tendons were calculated. The clinical outcomes of patients were evaluated according to the American Orthopaedic Foot and Ankle Society (AOFAS) score and Achilles Tendon Rupture Score (ATRS). An independent sample t-test was used to compare the differences of T2(⁎) value and clinical scores between two groups. The Pearson correlation coefficient between clinical scores and T2(⁎) values was assessed. Results. The T2(⁎) values of Achilles tendon were statistically significantly different between patients and volunteers. The Pearson correlation coefficients between T2(⁎) and AOFAS or ATRS scores of patients were r = -0.733 and r = -0.634, respectively. Conclusion. The variability of T2(⁎) in healthy and pathologic AT can be quantified by UTE-T2(⁎). T2(⁎) may be a promising marker to detect and diagnose AT tendinopathy. UTE-T2(⁎) could give a precise guidance to clinical outcome.

  10. UTE-T2⁎ Analysis of Diseased and Healthy Achilles Tendons and Correlation with Clinical Score: An In Vivo Preliminary Study

    Directory of Open Access Journals (Sweden)

    Yang Qiao

    2017-01-01

    Full Text Available Objective. To compare T2⁎ value of healthy and diseased Achilles tendons (AT with a recently introduced three-dimensional ultrashort echo time (3D-UTE sequence and analyze the correlation between T2⁎ value and clinical scores. Methods. Ten patients with symptomatic Achilles tendon and ten healthy volunteers were investigated with 3D-UTE sequence on a 3T magnetic resonance (MR scanner. T2⁎ values of four regions in Achilles tendons were calculated. The clinical outcomes of patients were evaluated according to the American Orthopaedic Foot and Ankle Society (AOFAS score and Achilles Tendon Rupture Score (ATRS. An independent sample t-test was used to compare the differences of T2⁎ value and clinical scores between two groups. The Pearson correlation coefficient between clinical scores and T2⁎ values was assessed. Results. The T2⁎ values of Achilles tendon were statistically significantly different between patients and volunteers. The Pearson correlation coefficients between T2⁎ and AOFAS or ATRS scores of patients were r=-0.733 and r=-0.634, respectively. Conclusion. The variability of T2⁎ in healthy and pathologic AT can be quantified by UTE-T2⁎. T2⁎ may be a promising marker to detect and diagnose AT tendinopathy. UTE-T2⁎ could give a precise guidance to clinical outcome.

  11. Magic angle effect plays a major role in both T1rho and T2 relaxation in articular cartilage.

    Science.gov (United States)

    Shao, H; Pauli, C; Li, S; Ma, Y; Tadros, A S; Kavanaugh, A; Chang, E Y; Tang, G; Du, J

    2017-02-01

    To investigate the effect of sample orientation on T1rho and T2 values of articular cartilage in histologically confirmed normal and abnormal regions using a whole-body 3T scanner. Eight human cadaveric patellae were evaluated using a 2D CPMG sequence for T2 measurement as well as a 2D spin-locking prepared spiral sequence and a 3D magnetization-prepared angle-modulated partitioned-k-space spoiled gradient echo snapshots (3D MAPSS) sequence for T1rho measurement. Each sample was imaged at six angles from 0° to 100° relative to the B0 field. T2 and T1rho values were measured for three regions (medial, apex and lateral) with three layers (10% superficial, 60% middle, 30% deep). Multiple histopathologically confirmed normal and abnormal regions were used to evaluate the angular dependence of T2 and T1rho relaxation in articular cartilage. Our study demonstrated a strong magic angle effect for T1rho and T2 relaxation in articular cartilage, especially in the deeper layers of cartilage. On average, T2 values were increased by 231.8% (72.2% for superficial, 237.6% for middle, and 187.9% for deep layers) while T1rho values were increased by 92% (31.7% for superficial, 69% for middle, and 140% for deep layers) near the magic angle. Both normal and abnormal cartilage showed similar T1rho and T2 magic angle effect. Changes in T1rho and T2 values due to the magic angle effect can be several times more than that caused by degeneration, and this may significantly complicate the clinical application of T1rho and T2 as an early surrogate marker for degeneration. Copyright © 2017 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  12. Quantitative T2 mapping for detecting myocardial edema after reperfusion of myocardial infarction: validation and comparison with T2-weighted images.

    Science.gov (United States)

    Park, Chul Hwan; Choi, Eui-Young; Kwon, Hyuck Moon; Hong, Bum Kee; Lee, Byoung Kwon; Yoon, Young Won; Min, Pil-Ki; Greiser, Andreas; Paek, Mun Young; Yu, Wei; Sung, Yon Mi; Hwang, Sung Ho; Hong, Yoo Jin; Kim, Tae Hoon

    2013-06-01

    This study evaluates the clinical usefulness of T2 mapping for the detection of myocardial edema in the re-perfused acute myocardial infarction (MI). Cardiac MRIs were reviewed in 20 patients who had acute MI after reperfusion therapy. The regional T2 values and T2-weighted image (T2WI) signal intensities (SI) were measured in the infarcted and remote zones of the myocardium. Patients were divided into three groups according to the signal patterns of the infarcted myocardium on the T2WIs. The T2 values of the infarcted zones were compared on the T2 maps among the three groups. Validation of the T2 values was performed in the normal myocardium of seven healthy volunteers. There were no significant differences in mean T2WI-SI or T2 values in the normal myocardium of healthy volunteers compared to the remote myocardium of acute MI patients (p > 0.05). Mean SI on the T2WIs was significantly higher in the infarcted myocardium (81.3 ± 37.6) than in the remote myocardium (63.8 ± 18.1) (p infarcted myocardium, compared to the remote myocardium. The T2 maps showed that T2 values in the infarcted myocardium had mostly increased, regardless of group, with values of 71 ± 9 ms in group 1, 64.9 ± 7.4 ms in group 2, and 61.4 ± 8.5 ms in group 3. T2 mapping is superior to T2WI for detecting areas of high SI in the infarcted myocardium. Therefore, quantitative T2 mapping sequences may be more useful and reliable in identifying myocardial edema in the infarcted myocardium than T2WI.

  13. Effect of Emetine on T-2 Toxin-Induced Inhibition of Protein Synthesis in Mammalian Cells

    Science.gov (United States)

    1993-01-01

    Inhibition of protein synthesis by trichothecenes . WEI, C. M., HANSEN, B. S., VAUGHAN, M. H. AND McLAUGHLIN, C. S.: In Mycotoxina in Human and...dependent manner. The dose-response curves for these potent trichothecenes , deoxynivalenol, T-2 tetraol and verru- two effects were nearly identical... trichothecene mycotoxin times of toxin-challenged animals. Exceptions to this were the produced by several species of the genus Fusarium (Ueno, steroidal anti

  14. Monitoring T2 and ADC at 9.4 T following fractionated external beam radiation therapy in a mouse model

    Science.gov (United States)

    Larocque, Matthew P.; Syme, Alasdair; Yahya, Atiyah; Wachowicz, Keith; Allalunis-Turner, Joan; Fallone, B. Gino

    2010-03-01

    The purpose of this study is to investigate the response of transverse relaxation time (T2) and apparent diffusion coefficient (ADC) in human glioma tumor xenografts during and after fractionated radiotherapy. Tumor-bearing mice were divided into four treatment groups (n = 6 per group) that received a total dose of 800 cGy of 200 kVp x-rays, given over two or three fractions, with a fraction spacing of either 24 or 72 h. A fifth treatment group received 800 cGy in a single fraction, and a sixth group of mice served as an untreated control. All mice were scanned pretreatment, before each fraction and at multiple points after treatment using a 9.4 T magnetic resonance imaging (MRI) system. Quantitative T2 and ADC maps were produced. All treated groups showed an increase in mean tumor ADC, though the time for this response to reach a maximum and return toward baseline was delayed in the fractionated groups. The highest ADC was measured 7 days after the final fraction of treatment for all groups. There were no significant differences in the maximum measured change in ADC between any of the treated groups, with the average measured maximum value being 20.5% above baseline. After treatment, all groups showed an increase in mean tumor T2, with the average measured maximum T2 being 4.7% above baseline. This increase was followed by a transition to mean T2 values below baseline values, with the average measured tumor T2 being 92.4% of the pretreatment value. The transition between elevated and depressed T2 values was delayed in the cases of fractionated therapies and occurred between 3.6 and 7.3 days after the last fraction of treatment. These results further the understanding of the temporal evolution of T2 and ADC during fractionated radiotherapy and support their potential use as time-sensitive biomarkers for tumor response.

  15. Quantitative T2 magnetic resonance imaging compared to morphological grading of the early cervical intervertebral disc degeneration: an evaluation approach in asymptomatic young adults.

    Directory of Open Access Journals (Sweden)

    Chun Chen

    Full Text Available OBJECTIVE: The objective of this study was to evaluate the efficacy of quantitative T2 magnetic resonance imaging (MRI for quantifying early cervical intervertebral disc (IVD degeneration in asymptomatic young adults by correlating the T2 value with Pfirrmann grade, sex, and anatomic level. METHODS: Seventy asymptomatic young subjects (34 men and 36 women; mean age, 22.80±2.11 yr; range, 18-25 years underwent 3.0-T MRI to obtain morphological data (one T1-fast spin echo (FSE and three-plane T2-FSE, used to assign a Pfirrmann grade (I-V and for T2 mapping (multi-echo spin echo. T2 values in the nucleus pulposus (NP, n = 350 and anulus fibrosus (AF, n = 700 were obtained. Differences in T2 values between sexes and anatomic level were evaluated, and linear correlation analysis of T2 values versus degenerative grade was conducted. FINDINGS: Cervical IVDs of healthy young adults were commonly determined to be at Pfirrmann grades I and II. T2 values of NPs were significantly higher than those of AF at all anatomic levels (P0.05. T2 values decreased linearly with degenerative grade. Linear correlation analysis revealed a strong negative association between the Pfirrmann grade and the T2 values of the NP (P = 0.000 but not the T2 values of the AF (P = 0.854. However, non-degenerated discs (Pfirrmann grades I and II showed a wide range of T2 relaxation time. T2 values according to disc degeneration level classification were as follows: grade I (>62.03 ms, grade II (54.60-62.03 ms, grade III (<54.60 ms. CONCLUSIONS: T2 quantitation provides a more sensitive and robust approach for detecting and characterizing the early stage of cervical IVD degeneration and to create a reliable quantitative in healthy young adults.

  16. Insulin initiation and intensification in patients with T2DM for the primary care physician

    Directory of Open Access Journals (Sweden)

    Unger J

    2011-06-01

    Full Text Available Jeff UngerCatalina Research Institute, Chino, CA, USAAbstract: Type 2 diabetes mellitus (T2DM is characterized by both insulin resistance and inadequate insulin secretion. All patients with the disease require treatment to achieve and maintain the target glycosylated hemoglobin (A1C level of 6.5%–7%. Pharmacological management of T2DM typically begins with the introduction of oral medications, and the majority of patients require exogenous insulin therapy at some point in time. Primary care physicians play an essential role in the management of T2DM since they often initiate insulin therapy and intensify regimens over time as needed. Although insulin therapy is prescribed on an individualized basis, treatment usually begins with basal insulin added to a background therapy of oral agents. Prandial insulin injections may be added if glycemic targets are not achieved. Treatments may be intensified over time using patient-friendly titration algorithms. The goal of insulin intensification within the primary care setting is to minimize patients' exposure to chronic hyperglycemia and weight gain, and reduce patients' risk of hypoglycemia, while achieving individualized fasting, postprandial, and A1C targets. Simplified treatment protocols and insulin delivery devices allow physicians to become efficient prescribers of insulin intensification within the primary care arena.Keywords: diabetes, basal, bolus, regimens, insulin analogs, structured glucose testing

  17. Wall conditioning and particle control in Extrap T2

    Science.gov (United States)

    Bergsåker, H.; Larsson, D.; Brunsell, P.; Möller, A.; Tramontin, L.

    1997-02-01

    The Extrap T2 reversed field pinch experiment is operated with the former OHTE vacuum vessel, of dimensions R = 1.24 m and a = 0.18 m and with a complete graphite liner. It is shown that a rudimentary density control can be achieved by means of frequent helium glow discharge conditioning of the wall. The standard He-GDC is well characterized and reproducible. The trapping and release of hydrogen and impurities at the wall surfaces have been studied by mass spectrometry and surface analysis. The shot to shot particle exchange between wall and plasma can be approximately accounted for.

  18. 新加坡采用DVB—T2

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    6月21日.新加坡媒体发展管理局宣布2013年底前全部免费地面电视频道将采用DVB—T2标准以完全数字化。随着新加坡向数字电视转换,免费广播机构新传媒将在2013年底前数字发射其全部7个免费电视频道。

  19. Methods of fetal MR: beyond T2-weighted imaging

    Energy Technology Data Exchange (ETDEWEB)

    Brugger, Peter C. [Center of Anatomy and Cell Biology, Integrative Morphology Group, Medical University of Vienna, Waehringerstrasse 13, 1090 Vienna (Austria)]. E-mail: peter.brugger@meduniwien.ac.at; Stuhr, Fritz [Department of Radiology, Medical University of Vienna, Waehringerguertel 18-20, 1090 Vienna (Austria); Lindner, Christian [Department of Radiology, Medical University of Vienna, Waehringerguertel 18-20, 1090 Vienna (Austria); Prayer, Daniela [Department of Radiology, Medical University of Vienna, Waehringerguertel 18-20, 1090 Vienna (Austria)

    2006-02-15

    The present work reviews the basic methods of performing fetal magnetic resonance imaging (MRI). Since fetal MRI differs in many respects from a postnatal study, several factors have to be taken into account to achieve satisfying image quality. Image quality depends on adequate positioning of the pregnant woman in the magnet, use of appropriate coils and the selection of sequences. Ultrafast T2-weighted sequences are regarded as the mainstay of fetal MR-imaging. However, additional sequences, such as T1-weighted images, diffusion-weighted images, echoplanar imaging may provide further information, especially in extra- central-nervous system regions of the fetal body.

  20. Neutrino Oscillation Physics Potential of the T2K Experiment

    CERN Document Server

    Abe, K; Aihara, H; Akiri, T; Andreopoulos, C; Aoki, S; Ariga, A; Assylbekov, S; Autiero, D; Barbi, M; Barker, G J; Barr, G; Bass, M; Batkiewicz, M; Bay, F; Berardi, V; Berger, B E; Berkman, S; Bhadra, S; Blaszczyk, F d M; Blondel, A; Bojechko, C; Bordoni, S; Boyd, S B; Brailsford, D; Bravar, A; Bronner, C; Buchanan, N; Calland, R G; Rodr'iguez, J Caravaca; Cartwright, S L; Castillo, R; Catanesi, M G; Cervera, A; Cherdack, D; Christodoulou, G; Clifton, A; Coleman, J; Coleman, S J; Collazuol, G; Connolly, K; Cremonesi, L; Dabrowska, A; Danko, I; Das, R; Davis, S; de Perio, P; De Rosa, G; Dealtry, T; Dennis, S R; Densham, C; Dewhurst, D; Di Lodovico, F; Di Luise, S; Drapier, O; Duboyski, T; Duffy, K; Dumarchez, J; Dytman, S; Dziewiecki, M; Emery-Schrenk, S; Ereditato, A; Escudero, L; Finch, A J; Friend, M; Fujii, Y; Fukuda, Y; Furmanski, A P; Galymov, V; Giffin, S; Giganti, C; Gilje, K; Goeldi, D; Golan, T; Gonin, M; Grant, N; Gudin, D; Hadley, D R; Haesler, A; Haigh, M D; Hamilton, P; Hansen, D; Hara, T; Hartz, M; Hasegawa, T; Hastings, N C; Hayato, Y; Hearty, C; Helmer, R L; Hierholzer, M; Hignight, J; Hillairet, A; Himmel, A; Hiraki, T; Hirota, S; Holeczek, J; Horikawa, S; Huang, K; Ichikawa, A K; Ieki, K; Ieva, M; Ikeda, M; Imber, J; Insler, J; Irvine, T J; Ishida, T; Ishii, T; Iwai, E; Iwamoto, K; Iyogi, K; Izmaylov, A; Jacob, A; Jamieson, B; Johnson, R A; Johnson, S; Jo, J H; Jonsson, P; Jung, C K; Kabirnezhad, M; Kaboth, A C; Kajita, T; Kakuno, H; Kameda, J; Kanazawa, Y; Karlen, D; Karpikov, I; Katori, T; Kearns, E; Khabibullin, M; Khotjantsev, A; Kielczewska, D; Kikawa, T; Kilinski, A; Kim, J; King, S; Kisiel, J; Kitching, P; Kobayashi, T; Koch, L; Kolaceke, A; Konaka, A; Kormos, L L; Korzenev, A; Koseki, K; Koshio, Y; Kropp, W; Kubo, H; Kudenko, Y; Kurjata, R; Kutter, T; Lagoda, J; Laihem, K; Lamont, I; Larkin, E; Laveder, M; Lawe, M; Lazos, M; Lindner, T; Lister, C; Litchfield, R P; Longhin, A; Ludovici, L; Magaletti, L; Mahn, K; Malek, M; Manly, S; Marino, A D; Marteau, J; Martin, J F; Martynenko, S; Maruyama, T; Matveev, V; Mavrokoridis, K; Mazzucato, E; McCarthy, M; McCauley, N; McFarland, K S; McGrew, C; Mefodiev, A; Metelko, C; Mezzetto, M; Mijakowski, P; Miller, C A; Minamino, A; Mineev, O; Missert, A; Miura, M; Moriyama, S; Mueller, Th A; Murakami, A; Murdoch, M; Murphy, S; Myslik, J; Nakadaira, T; Nakahata, M; Nakamura, K; Nakayama, S; Nakaya, T; Nakayoshi, K; Nielsen, C; Nirkko, M; Nishikawa, K; Nishimura, Y; O'Keeffe, H M; Ohta, R; Okumura, K; Okusawa, T; Oryszczak, W; Oser, S M; Ovsyannikova, T; Owen, R A; Oyama, Y; Palladino, V; Palomino, J L; Paolone, V; Payne, D; Perevozchikov, O; Perkin, J D; Petrov, Y; Pickard, L; Guerra, E S Pinzon; Pistillo, C; Plonski, P; Poplawska, E; Popov, B; Posiadala-Zezula, M; Poutissou, J -M; Poutissou, R; Przewlocki, P; Quilain, B; Radicioni, E; Ratoff, P N; Ravonel, M; Rayner, M A M; Redij, A; Reeves, M; Reinherz-Aronis, E; Riccio, C; Rodrigues, P A; Rojas, P; Rondio, E; Roth, S; Rubbia, A; Ruterbories, D; Sacco, R; Sakashita, K; S'anchez, F; Sato, F; Scantamburlo, E; Scholberg, K; Schoppmann, S; Schwehr, J; Scott, M; Seiya, Y; Sekiguchi, T; Sekiya, H; Sgalaberna, D; Shaker, F; Shiozawa, M; Short, S; Shustrov, Y; Sinclair, P; Smith, B; Smy, M; Sobczyk, J T; Sobel, H; Sorel, M; Southwell, L; Stamoulis, P; Steinmann, J; Still, B; Suda, Y; Suzuki, A; Suzuki, K; Suzuki, S Y; Suzuki, Y; Tacik, R; Tada, M; Takahashi, S; Takeda, A; Takeuchi, Y; Tanaka, H K; Tanaka, H A; Tanaka, M M; Terhorst, D; Terri, R; Thompson, L F; Thorley, A; Tobayama, S; Toki, W; Tomura, T; Totsuka, Y; Touramanis, C; Tsukamoto, T; Tzanov, M; Uchida, Y; Vacheret, A; Vagins, M; Vasseur, G; Wachala, T; Waldron, A V; Walter, C W; Wark, D; Wascko, M O; Weber, A; Wendell, R; Wilkes, R J; Wilking, M J; Wilkinson, C; Williamson, Z; Wilson, J R; Wilson, R J; Wongjirad, T; Yamada, Y; Yamamoto, K; Yanagisawa, C; Yano, T; Yen, S; Yershov, N; Yokoyama, M; Yuan, T; Yu, M; Zalewska, A; Zalipska, J; Zambelli, L; Zaremba, K; Ziembicki, M; Zimmerman, E D; Zito, M; Zmuda, J

    2014-01-01

    The observation of the recent electron neutrino appearance in a muon neutrino beam and the high-precision measurement of the mixing angle $\\theta_{13}$ have led to a re-evaluation of the physics potential of the T2K long-baseline neutrino oscillation experiment. Sensitivities are explored for CP violation in neutrinos, non-maximal $\\sin^22\\theta_{23}$, the octant of $\\theta_{23}$, and the mass hierarchy, in addition to the measurements of $\\delta_{CP}$, $\\sin^2\\theta_{23}$, and $\\Delta m^2_{32}$, for various combinations of $\

  1. Two-photon interference from a quantum dot-microcavity: Persistent pure-dephasing and suppression of time-jitter

    DEFF Research Database (Denmark)

    Unsleber, Sebastian; McCutcheon, Dara; Dambach, Michael;

    2015-01-01

    , we observea threefold improvement in the Hong-Ou-Mandel interference visibility, reaching values in excess of 80%. Ourmeasurements off-resonance allow us to investigate varying Purcell enhancements, and to probe the dephasingenvironment at different temperatures and energy scales. By comparison...

  2. Two-photon interference from a quantum dot-microcavity: Persistent pure-dephasing and suppression of time-jitter

    DEFF Research Database (Denmark)

    Unsleber, S.; McCutcheon, Dara; Dambach, M.;

    We demonstrate the emission of highly indistinguishable photons from a quasiresonantly pumped coupled quantum dot–microcavity system operating in the regime of cavity quantum electrodynamics. Changing the sample temperature allows us to vary the quantum dot–cavity detuning, and on spectral...

  3. MR imaging and T2 measurements in peripheral nerve repair with activation of Toll-like receptor 4 of neurotmesis

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiang; Zhang, Fang; Lu, Liejing; Li, Haojiang; Wen, Xuehua; Shen, Jun [Sun Yat-Sen University, Department of Radiology, Sun Yat-Sen Memorial Hospital, Guangzhou, Guangdong (China)

    2014-05-15

    To investigate the role of MR imaging in neurotmesis combined with surgical repair and Toll-like receptor 4 (TLR4) activation. Forty-eight rats received subepineurial microinjection of the TLR4 agonist lipopolysaccharide (LPS, n = 24) or phosphate buffered saline (PBS, n = 24) immediately after surgical repair of the transected sciatic nerve. Sequential fat-suppressed T2-weighted imaging and quantitative T2 measurements were obtained at 3, 7, 14 and 21 days after surgery, with histologic assessments performed at regular intervals. T2 relaxation times and histological quantification of the distal stumps were measured and compared. The distal stumps of transected nerves treated with LPS or PBS both showed persistent enlargement and hyperintense signal. T2 values of the distal stumps showed a rapid rise to peak level followed by a rapid decline pattern in nerves treated with LPS, while exhibiting a slow rise to peak value followed by a slow decline in nerves treated with PBS. Nerves treated with LPS exhibited more prominent macrophage recruitment, faster myelin debris clearance and more pronounced nerve regeneration. Nerves treated with TLR4 activation had a characteristic pattern of T2 value change over time. Longitudinal T2 measurements can be used to detect the enhanced repair effect associated with TLR4 activation in the surgical repair of neurotmesis. (orig.)

  4. Long coherence times in self-assembled semiconductor quantum dots

    DEFF Research Database (Denmark)

    Birkedal, Dan; Leosson, K.; Hvam, Jørn Märcher

    2002-01-01

    We report measurements of ultra-long coherence in self-assembled quantum dots. Transient four-wave mixing experiments at 5 K show an average dephasing time of 372 ps, corresponding to a homogeneous linewidth of 3.5 mueV, which is significantly smaller than the linewidth observed in single-dot...... luminescence. Time-resolved luminescence measurements show a lifetime of the dot ground state of 800 ps demonstrating the presence of pure dephasing at finite temperature. The homogeneous width is lifetime limited only at temperatures approaching 0 K....

  5. Identification and characterization of tissues by T2-selective whole-body proton NMR imaging.

    Science.gov (United States)

    Gersonde, K; Tolxdorff, T; Felsberg, L

    1985-08-01

    T2-selective proton imaging at 10 MHz is based on a Carr-Purcell-Meiboom-Gill pulse sequence with at least 36 echoes and 2 tau greater than or equal to 6 ms employing the projection reconstruction technique. The transverse magnetization decay of the volume elements is multiexponential composed of up to three monoexponential T2 components. The T2 values are arranged in T2 histograms which are slice specific. T2 windows are defined in the T2 histogram and used for imaging and for selecting T2 values which are assigned to proton classes and tissues. Tissue characterization is based on the visualization of differences in T2 behavior. The T2 values are transformed into 256 gray levels or, by use of a red-green-blue lookup table, into a rainbow code. Two display techniques have been developed and implemented in the RWTH Aachen Magnetic Resonance Software System (RAMSES): (i) for nonselective T2 imaging with secondary T2 selection and encoding of molecular classes on the basis of T2 values; (ii) for T2-selective imaging by employing combined primary and secondary T2 selection and encoding particular tissues and variations therein. The tissues can be identified by selecting different classes of molecules, like water, lipids, and proteins, when shifting the primary T2 window on the T2 axis of the T2 histogram.

  6. T2Ku: Building a Semantic Wiki of Mathematics

    CERN Document Server

    Pan, Minqi

    2012-01-01

    We introduce T2Ku, an open source project that aims at building a semantic wiki of mathematics featuring automated reasoning(AR) techniques. We want to utilize AR techniques in a way that truly helps mathematical researchers solve problems in the real world, instead of building another ambitious yet useless system. By setting this as our objective, we exploit pragmatic design decisions that have proven feasible in other projects, while still employs a loosely coupled architecture to allow better inference programs to be integrated in the future. In this paper, we state the motivations and examine state-of-the-art systems, why we are not satisfied with those systems and how we are going to improve. We then describe our architecture and the way we implemented the system. We present examples showing how to use its facilities. T2Ku is an on-going project. We conclude this paper by summarizing the development progress and encouraging the reader to join the project.

  7. Detection of degenerative cartilage disease: comparison of high-resolution morphological MR and quantitative T2 mapping at 3.0 Tesla.

    Science.gov (United States)

    Apprich, S; Welsch, G H; Mamisch, T C; Szomolanyi, P; Mayerhoefer, M; Pinker, K; Trattnig, S

    2010-09-01

    The aim of the study was to investigate the association of T2 relaxation times of the knee with early degenerative cartilage changes. Furthermore the impact of unloading the knee on T2 values was evaluated. Forty-three patients with knee pain and an ICRS (International Cartilage Repair Society) cartilage defect grade Morphological cartilage grading was based on high-resolution proton-density (PD), turbo-spin-echo (TSE) and three-dimensional (3D) isotropic True fast imaging with steady-state precession (FISP) images of slices covering the cartilage layer above the posterior horn of the meniscus. T2 maps were calculated from a multi-echo, spin-echo (MESE) sequence, performed at the beginning and at the end of the scan (time interval 40 min). Influence of cartilage defect grading on deep, superficial, and global T2 values as well as on T2 values for zonal variation was assessed using analysis of variance (ANOVA) and Spearman rank correlation test. Differences among both T2 measurements were compared using paired t-test. Global and superficial T2 values significantly increased with cartilage defect grade regardless of the time elapsed from unloading (global T2: ICRS grade 0, 38.9 and 40.1 ms; grade 1, 41.2 and 44.5 ms; grade 2, 47.7 and 53.4 ms; P=0.041 and 0.008) with stronger correlation for second T2 measurement. In contrast there were no significant differences among grades in the zonal variation at any time. Significant differences for T2 values between the two subsequent measurements were consistently found. T2 mapping might be a sensitive method for the detection of early cartilage degeneration. From our results we would recommend to measure T2 after unloading. Copyright 2010. Published by Elsevier Ltd.

  8. Effect of physiological heart rate variability on quantitative T2 measurement with ECG-gated Fast Spin Echo (FSE) sequence and its retrospective correction.

    Science.gov (United States)

    de Roquefeuil, Marion; Vuissoz, Pierre-André; Escanyé, Jean-Marie; Felblinger, Jacques

    2013-11-01

    Quantitative T2 measurement is applied in cardiac Magnetic Resonance Imaging (MRI) for the diagnosis and follow-up of myocardial pathologies. Standard Electrocardiogram (ECG)-gated fast spin echo pulse sequences can be used clinically for T2 assessment, with multiple breath-holds. However, heart rate is subject to physiological variability, which causes repetition time variations and affects the recovery of longitudinal magnetization between TR periods. The bias caused by heart rate variability on quantitative T2 measurements is evaluated for fast spin echo pulse sequence. Its retrospective correction based on an effective TR is proposed. Heart rate variations during breath-holds are provided by the ECG recordings from healthy volunteers. T2 measurements were performed on a phantom with known T2 values, by synchronizing the sequence with the recorded ECG. Cardiac T2 measurements were performed twice on six volunteers. The impact of T1 on T2 is also studied. Maximum error in T2 is 26% for phantoms and 18% for myocardial measurement. It is reduced by the proposed compensation method to 20% for phantoms and 10% for in vivo measurements. Only approximate knowledge of T1 is needed for T2 correction. Heart rate variability may cause a bias in T2 measurement with ECG-gated FSE. It needs to be taken into account to avoid a misleading diagnosis from the measurements. © 2013.

  9. Increased T2 signal intensity in the distal clavicle: incidence and clinical implications

    Energy Technology Data Exchange (ETDEWEB)

    Fiorella, D.; Helms, C.A. [Dept. of Radiology, Duke Univ., Durham, NC (United States); Speer, K.P. [Dept. of Orthopedic Surgery, Duke Univ., Durham, NC (United States)

    2000-12-01

    Objective. The objectives of the current study were (1) to quantify the incidence of increased T2 signal in the distal clavicle and (2) to assess the clinical significance of this finding in patients with chronic acromioclavicular (AC) joint pain.Design and patients. Eight patients (five male and three female, 15-41 years of age) with disabling shoulder pain localized to the AC joint and marked increased T2 signal in the distal clavicle are presented. These eight patients underwent MR examination over a 25 month period (August 1996 to September 1998). The dictated reports of all shoulder MR examinations conducted over this same time period were reviewed retrospectively for the presence of signal abnormality in the distal cla-vicle. Clinical data and, in five patients, findings at shoulder arthroscopy or open surgery, were correlated with the results of MR imaging. One patient underwent arthroscopy on both shoulders.Results. The selected eight patients each presented clinically with disabling shoulder pain localized to the AC joint. One patient is presented twice, as both shoulders were symptomatic (n=9). Plain film examination (9/9) failed to indicate a structural cause of shoulder pain in any of the patients. MR examination demonstrated abnormally increased T2 signal in the distal clavicle in all nine cases and no other cause for AC joint pain. Three patients responded to a course of conservative therapy. Six experienced refractory pain despite conservative therapy. Resection of the distal clavicle was performed in five of the six cases. All patients who underwent resection of the distal clavicle experienced complete resolution of AC joint pain. A retrospective review of the dictated reports for all shoulder MR imaging examinations performed at out institution over a 25 month period (August 1996 to September 1998; n=761) demonstrated a 12.5% incidence of abnormally increased T2 signal in the distal clav-icle.Conclusions. Increased T2 signal in the distal clavicle

  10. Longitudinal monitoring of cardiac siderosis using cardiovascular magnetic resonance T2* in patients with thalassemia major on various chelation regimens: a 6-year study.

    Science.gov (United States)

    Ambati, Srikanth R; Randolph, Rachel E; Mennitt, Kevin; Kleinert, Dorothy A; Weinsaft, Jonathan W; Giardina, Patricia J

    2013-08-01

    Cardiovascular magnetic resonance (CMR) and hepatic magnetic resonance imaging (MRI) have become reliable noninvasive tools to monitor iron excess in thalassemia major (TM) patients. However, long-term studies are lacking. We reviewed CMR and hepatic MRI T2* imaging on 54 TM patients who had three or more annual measurements. They were managed on various chelation regimens. Patients were grouped according to their degree of cardiac siderosis: severe (T2*, cardiac siderosis (T2*, >20 msec). We looked at the change in cardiac T2*, liver iron concentration (LIC) and left ventricular ejection fraction (LVEF) at years 3 and 5. In patients with severe cardiac siderosis, cardiac T2* (mean ± SD) improved from 6.9 ± 1.6 at baseline to 13.6 ± 10.0 by year 5, mean ΔT2* = 6.7 (P = 0.04). Change in cardiac T2* at year 3 was not significant in the severe group. Patients with mild to moderate cardiac siderosis had mean cardiac T2* of 14.6 ± 2.9 at baseline which improved to 26.3 ± 9.5 by year 3, mean ΔT2* =  1.7 (P = 0.01). At baseline, median LICs (mg/g dry weight) in patients with severe, mild-moderate, and no cardiac siderosis were 3.6, 2.8, and 3.3, whereas LVEFs (mean ± SD) (%) were 56.3 ± 10.1, 60 ± 5, and 66 ± 7.6, respectively. No significant correlation was noted between Δ cardiac T2* and Δ LIC, Δ cardiac T2*, and Δ LVEF at years 3 and 5. Throughout the observation period, patients with no cardiac siderosis maintained their cardiac T2* above 20 msec. The majority of patients with cardiac siderosis improve cardiac T2* over time with optimal chelation.

  11. Evaluation of MR imaging with T1 and T2* mapping for the determination of hepatic iron overload

    Energy Technology Data Exchange (ETDEWEB)

    Henninger, B.; Kremser, C.; Rauch, S.; Eder, R.; Schocke, M. [Innsbruck Medical University, Department of Radiology, Innsbruck (Austria); Zoller, H.; Finkenstedt, A. [Innsbruck Medical University, Department of Internal Medicine, Innsbruck (Austria); Michaely, H.J. [Medical Faculty Mannheim - Heidelberg University, Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Mannheim (Germany)

    2012-11-15

    To evaluate MRI using T1 and T2* mapping sequences in patients with suspected hepatic iron overload (HIO). Twenty-five consecutive patients with clinically suspected HIO were retrospectively studied. All underwent MRI and liver biopsy. For the quantification of liver T2* values we used a fat-saturated multi-echo gradient echo sequence with 12 echoes (TR = 200 ms, TE = 0.99 ms + n x 1.41 ms, flip angle 20 ). T1 values were obtained using a fast T1 mapping sequence based on an inversion recovery snapshot FLASH sequence. Parameter maps were analysed using regions of interest. ROC analysis calculated cut-off points at 10.07 ms and 15.47 ms for T2* in the determination of HIO with accuracy 88 %/88 %, sensitivity 84 %/89.5 % and specificity 100 %/83 %. MRI correctly classified 20 patients (80 %). All patients with HIO only had decreased T1 and T2* relaxation times. There was a significant difference in T1 between patients with HIO only and patients with HIO and steatohepatitis (P = 0.018). MRI-based T2* relaxation diagnoses HIO very accurately, even at low iron concentrations. Important additional information may be obtained by the combination of T1 and T2* mapping. It is a rapid, non-invasive, accurate and reproducible technique for validating the evidence of even low hepatic iron concentrations. (orig.)

  12. Recombinant T2 RNase protein of Schistosoma japonicum inhibits expression of α-SMA in LX-2 cells.

    Science.gov (United States)

    Wang, Jianxin; Peng, Wenxia; Feng, Jinrong; Zhu, Dandan; Chen, Jinling; Sun, Xiaolei; Lyu, Lei; Ju, Shaoqing; Duan, Yinong

    2016-10-01

    Recombinant T2 RNase glycoprotein, which showed a certain degree of homology to Omega-1 from Schistosoma mansoni eggs, was expressed in adult worms of Schistosoma japonicum, but not in eggs of S. japonicum. The direct biological role of the recombinant T2 RNase protein in activation of hepatic stellate cells (HSCs) remains unknown. In the present study, the immortalized human HSC line (LX-2 cells) was treated with the recombinant T2 RNase protein at indicated concentrations for various time points in vitro. The expression levels of α-smooth muscle actin (α-SMA) and Smad4 were detected by Western blot. The results showed that the recombinant T2 RNase protein significantly diminished the expression levels of α-SMA and Smad4 in LX-2 cells. The upregulated expression levels of α-SMA and Smad4 by TGF-β1 in LX-2 cells were both suppressed by the recombinant T2 RNase protein. These data suggest that the recombinant T2 RNase protein may be a potential target of therapeutic strategy for the treatment of hepatic fibrosis.

  13. Optimized T1- and T2-weighted volumetric brain imaging as a diagnostic tool in very preterm neonates

    Energy Technology Data Exchange (ETDEWEB)

    Nossin-Manor, Revital [Neurosciences and Mental Health, Research Institute, Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto (Canada); Chung, Andrew D.; Morris, Drew; Thomas, Bejoy; Shroff, Manohar M. [The Hospital for Sick Children, Department of Diagnostic Imaging, Toronto (Canada); Soares-Fernandes, Joao P. [The Hospital for Sick Children, Department of Diagnostic Imaging, Toronto (Canada); Hospital de S. Marcos, Neuroradiology Department, Braga (Portugal); Cheng, Hai-Ling M. [The Hospital for Sick Children, Department of Diagnostic Imaging, Physiology Experimental Medicine, Research Institute, Toronto (Canada); University of Toronto, Medical Biophysics Department, Toronto (Canada); Whyte, Hilary E.A. [Neurosciences and Mental Health, Research Institute, Neonatology Department, The Hospital for Sick Children, Toronto (Canada); Taylor, Margot J. [The Hospital for Sick Children, Neurosciences and Mental Health, Research Institute, Department of Diagnostic Imaging, Toronto (Canada); University of Toronto, Medical Imaging, Toronto (Canada); Sled, John G. [University of Toronto, Physiology Experimental Medicine, Research Institute, The Hospital for Sick Children, Medical Biophysics, Toronto (Canada)

    2011-06-15

    T1- and T2-W MR sequences used for obtaining diagnostic information and morphometric measurements in the neonatal brain are frequently acquired using different imaging protocols. Optimizing one protocol for obtaining both kinds of information is valuable. To determine whether high-resolution T1- and T2-W volumetric sequences optimized for preterm brain imaging could provide both diagnostic and morphometric value. Thirty preterm neonates born between 24 and 32 weeks' gestational age were scanned during the first 2 weeks after birth. T1- and T2-W high-resolution sequences were optimized in terms of signal-to-noise ratio, contrast-to-noise ratio and scan time and compared to conventional spin-echo-based sequences. No differences were found between conventional and high-resolution T1-W sequences for diagnostic confidence, image quality and motion artifacts. A preference for conventional over high-resolution T2-W sequences for image quality was observed. High-resolution T1 images provided better delineation of thalamic myelination and the superior temporal sulcus. No differences were found for detection of myelination and sulcation using conventional and high-resolution T2-W images. High-resolution T1- and T2-W volumetric sequences can be used in clinical MRI in the very preterm brain to provide both diagnostic and morphometric information. (orig.)

  14. T2 mapping and quantitative analysis of the porcine patellar osteoarthritis model in vitro by collagenase%胶原酶消化猪髌软骨模型T2 mapping 成像与定量分析

    Institute of Scientific and Technical Information of China (English)

    杨朝湘; 王伟; Queenie Chan; 陈玲; 梁文; 全显跃

    2015-01-01

    Objective To investigate the ability of T2 mapping in early detection of the change of cartilage collagen by quantitative analysis.Methods 20 porcine patellae were randomly assigned into 4 groups,3 treated groups and 1 control group.The samples of 3 treated groups were respectively immersed in PBS with 100 mg/100 mL,1 50 mg/100 mL and 200 mg/100 mL typeⅡ collagenase for 4 h,whereas control group samples in PBS for 4 h.T2 relaxation times of superficial,deep and full layers of cartilage and mean densi-ty after Van Gieson stain were measured.The correlation of T2 relaxation times and mean density were statistically analyzed.Results Gross pathology showed all articular cartilages maintained intact after treatment.T2 relaxation times of superficial and full layers and mean density increased significantly in any treated group in comparison with control group(P 0.05).Pearson correlation analysis showed a close correlation(r=-0.837)between T2 relaxation times of full layers and mean density.Conclusion T2 map-ping can adequately detect the change of cartilage collagen in the early stage of osteoarthritis,and shows a good clinical application prospect.%目的:定量分析 T2 mapping 技术检测早期关节软骨退变中胶原含量变化的能力,并探讨其机制和意义。方法20个家猪髌骨随机分为4组,分别经浓度100 mg/100 mL、150 mg/100 mL、200 mg/100 mL 的Ⅱ型胶原酶(酶处理组)和无酶 PBS 缓冲液(对照组)处理。处理后髌骨行 MR T2 WI 和 T2 mapping 成像。分别测定髌关节软骨浅深2层和全层的 T2值。采用 Van Gieson染色法对软骨标本进行染色,并测定各组软骨染色后的平均光密度,分析软骨 T2值与平均光密度之间的关系。结果大体病理示各组髌骨软骨与处理前相比,软骨表面均无明显变化。统计学分析表明,各处理组与对照组比较,在软骨浅层与全层 T2值以及软骨平均光密度值上均有明显差异(P 0.05)

  15. T-2 toxin, a trichothecene mycotoxin: review of toxicity, metabolism, and analytical methods.

    Science.gov (United States)

    Li, Yanshen; Wang, Zhanhui; Beier, Ross C; Shen, Jianzhong; De Smet, David; De Saeger, Sarah; Zhang, Suxia

    2011-04-27

    This review focuses on the toxicity and metabolism of T-2 toxin and analytical methods used for the determination of T-2 toxin. Among the naturally occurring trichothecenes in food and feed, T-2 toxin is a cytotoxic fungal secondary metabolite produced by various species of Fusarium. Following ingestion, T-2 toxin causes acute and chronic toxicity and induces apoptosis in the immune system and fetal tissues. T-2 toxin is usually metabolized and eliminated after ingestion, yielding more than 20 metabolites. Consequently, there is a possibility of human consumption of animal products contaminated with T-2 toxin and its metabolites. Several methods for the determination of T-2 toxin based on traditional chromatographic, immunoassay, or mass spectroscopy techniques are described. This review will contribute to a better understanding of T-2 toxin exposure in animals and humans and T-2 toxin metabolism, toxicity, and analytical methods, which may be useful in risk assessment and control of T-2 toxin exposure.

  16. Edge profiles and limiter tests in Extrap T2

    Science.gov (United States)

    Bergsåker, H.; Hedin, G.; Ilyinsky, L.; Larsson, D.; Möller, A.

    New edge profile measurements, including calorimetric measurements of the parallel heat flux, were made in Extrap T2. Test limiters of pure molybdenum and the TZM molybdenum alloy have been exposed in the edge plasma. The surface damage was studied, mainly by microscopy. Tungsten coated graphite probes were also exposed, and the surfaces were studied by microscopy, ion beam analysis and XPS. In this case cracking and mixing of carbon and tungsten at the interface was observed in the most heated areas, whereas carbide formation at the surface was seen in less heated areas. In these tests pure Mo generally fared better than TZM, and thin and cleaner coatings fared better than thicker and less clean.

  17. DVB-T2标准探讨

    Institute of Scientific and Technical Information of China (English)

    张铭

    2010-01-01

    一 DVB—T与DVB—T2DVB-T(Digital Video Broadcasting—Terrestrial),即地面数字电视广播,是目前全球范围内应用最广泛,最成功的一款地面数字电视广播标准。然而DVB-T也有自己的缺点,例如,频带损失严重,在交织深度,抗脉;中噪声干扰及信道编码等方面的性能存在明显不足等。随着地面数字电视广播事业的发展,

  18. Recent Results from the T2K Experiment

    Science.gov (United States)

    Abe, K.; Abgrall, N.; Aihara, H.; Akiri, T.; Andreopoulos, C.; Aoki, S.; Ariga, A.; Ariga, T.; Assylbekov, S.; Autiero, D.; Barbi, M.; Barker, G. J.; Barr, G.; Bass, M.; Batkiewicz, M.; Bay, F.; Bentham, S. W.; Berardi, V.; Berger, B. E.; Berkman, S.; Bertram, I.; Bhadra, S.; Blaszczyk, F. D. M.; Blondel, A.; Bojechko, C.; Boyd, S. B.; Brailsford, D.; Bravar, A.; Bronner, C.; Buchanan, N.; Calland, R. G.; Caravaca Rodríguez, J.; Cartwright, S. L.; Castillo, R.; Catanesi, M. G.; Cervera, A.; Cherdack, D.; Christodoulou, G.; Clifton, A.; Coleman, J.; Coleman, S. J.; Collazuol, G.; Connolly, K.; Cremonesi, L.; Curioni, A.; Dabrowska, A.; Danko, I.; Das, R.; Davis, S.; de Perio, P.; De Rosa, G.; Dealtry, T.; Dennis, S. R.; Densham, C.; Di Lodovico, F.; Di Luise, S.; Drapier, O.; Duboyski, T.; Dufour, F.; Dumarchez, J.; Dytman, S.; Dziewiecki, M.; Emery, S.; Ereditato, A.; Escudero, L.; Finch, A. J.; Frank, E.; Friend, M.; Fujii, Y.; Fukuda, Y.; Furmanski, A. P.; Galymov, V.; Gaudin, A.; Giffin, S.; Giganti, C.; Gilje, K.; Golan, T.; Gomez-Cadenas, J. J.; Gonin, M.; Grant, N.; Gudin, D.; Hadley, D. R.; Haesler, A.; Haigh, M. D.; Hamilton, P.; Hansen, D.; Hara, T.; Hartz, M.; Hasegawa, T.; Hastings, N. C.; Hayato, Y.; Hearty, C.; Helmer, R. L.; Hierholzer, M.; Hignight, J.; Hillairet, A.; Himmel, A.; Hiraki, T.; Hirota, S.; Holeczek, J.; Horikawa, S.; Huang, K.; Ichikawa, A. K.; Ieki, K.; Ieva, M.; Ikeda, M.; Imber, J.; Insler, J.; Irvine, T. J.; Ishida, T.; Ishii, T.; Ives, S. J.; Iyogi, K.; Izmaylov, A.; Jacob, A.; Jamieson, B.; Johnson, R. A.; Jo, J. H.; Jonsson, P.; Joo, K. K.; Jung, C. K.; Kaboth, A. C.; Kajita, T.; Kakuno, H.; Kameda, J.; Kanazawa, Y.; Karlen, D.; Karpikov, I.; Kearns, E.; Khabibullin, M.; Khotjantsev, A.; Kielczewska, D.; Kikawa, T.; Kilinski, A.; Kim, J.; Kim, S. B.; Kisiel, J.; Kitching, P.; Kobayashi, T.; Kogan, G.; Kolaceke, A.; Konaka, A.; Kormos, L. L.; Korzenev, A.; Koseki, K.; Koshio, Y.; Kreslo, I.; Kropp, W.; Kubo, H.; Kudenko, Y.; Kumaratunga, S.; Kurjata, R.; Kutter, T.; Lagoda, J.; Laihem, K.; Laveder, M.; Lawe, M.; Lazos, M.; Lee, K. P.; Licciardi, C.; Lim, I. T.; Lindner, T.; Lister, C.; Litchfield, R. P.; Longhin, A.; Lopez, G. D.; Ludovici, L.; Macaire, M.; Magaletti, L.; Mahn, K.; Malek, M.; Manly, S.; Marino, A. D.; Marteau, J.; Martin, J. F.; Maruyama, T.; Marzec, J.; Masliah, P.; Mathie, E. L.; Matveev, V.; Mavrokoridis, K.; Mazzucato, E.; McCauley, N.; McFarland, K. S.; McGrew, C.; Metelko, C.; Mijakowski, P.; Miller, C. A.; Minamino, A.; Mineev, O.; Mine, S.; Missert, A.; Miura, M.; Monfregola, L.; Moriyama, S.; Mueller, Th. A.; Murakami, A.; Murdoch, M.; Murphy, S.; Myslik, J.; Nagasaki, T.; Nakadaira, T.; Nakahata, M.; Nakai, T.; Nakamura, K.; Nakayama, S.; Nakaya, T.; Nakayoshi, K.; Nielsen, C.; Nirkko, M.; Nishikawa, K.; Nishimura, Y.; O'Keeffe, H. M.; Ohta, R.; Okumura, K.; Okusawa, T.; Oryszczak, W.; Oser, S. M.; Otani, M.; Owen, R. A.; Oyama, Y.; Pac, M. Y.; Palladino, V.; Paolone, V.; Payne, D.; Pearce, G. F.; Perevozchikov, O.; Perkin, J. D.; Petrov, Y.; Pinzon Guerra, E. S.; Pistillo, C.; Plonski, P.; Poplawska, E.; Popov, B.; Posiadala, M.; Poutissou, J.-M.; Poutissou, R.; Przewlocki, P.; Quilain, B.; Radicioni, E.; Ratoff, P. N.; Ravonel, M.; Rayner, M. A. M.; Redij, A.; Reeves, M.; Reinherz-Aronis, E.; Retiere, F.; Robert, A.; Rodrigues, P. A.; Rondio, E.; Roth, S.; Rubbia, A.; Ruterbories, D.; Sacco, R.; Sakashita, K.; Sánchez, F.; Scantamburlo, E.; Scholberg, K.; Schwehr, J.; Scott, M.; Seiya, Y.; Sekiguchi, T.; Sekiya, H.; Sgalaberna, D.; Shiozawa, M.; Short, S.; Shustrov, Y.; Sinclair, P.; Smith, B.; Smith, R. J.; Smy, M.; Sobczyk, J. T.; Sobel, H.; Sorel, M.; Southwell, L.; Stamoulis, P.; Steinmann, J.; Still, B.; Suda, Y.; Suzuki, A.; Suzuki, K.; Suzuki, S. Y.; Suzuki, Y.; Szeglowski, T.; Tacik, R.; Tada, M.; Takahashi, S.; Takeda, A.; Takeuchi, Y.; Tanaka, H. A.; Tanaka, M. M.; Taylor, I. J.; Terhorst, D.; Terri, R.; Thompson, L. F.; Thorley, A.; Tobayama, S.; Toki, W.; Tomura, T.; Totsuka, Y.; Touramanis, C.; Tsukamoto, T.; Tzanov, M.; Uchida, Y.; Ueno, K.; Vacheret, A.; Vagins, M.; Vasseur, G.; Wachala, T.; Waldron, A. V.; Walter, C. W.; Wark, D.; Wascko, M. O.; Weber, A.; Wendell, R.; Wilkes, R. J.; Wilking, M. J.; Wilkinson, C.; Williamson, Z.; Wilson, J. R.; Wilson, R. J.; Wongjirad, T.; Yamada, Y.; Yamamoto, K.; Yanagisawa, C.; Yen, S.; Yershov, N.; Yokoyama, M.; Yuan, T.; Zalewska, A.; Zalipska, J.; Zambelli, L.; Zaremba, K.; Ziembicki, M.; Zimmerman, E. D.; Zito, M.; Żmuda, J.

    2014-01-01

    The Tokai to Kamioka (T2K) experiment studies neutrino oscillations using a beam of muon neutrinos produced by an accelerator. The neutrinos travel from J-PARC on the east coast of Japan and are detected 295 kilometers further away in the Super-Kamiokande detector. A complex of near detectors located 280 meters away from the neutrino production target is used to better characterize the neutrino beam and reduce systematic uncertainties. The experiment aims at measuring electronic neutrino appearance (νμ →νe oscillation) to measure the neutrino mixing angle θ13, and muon neutrino disappearance to measure the neutrino mixing angle θ23 and mass splitting | Δ m322 |. We report here electron neutrino appearance results using three years of data, recorded until the 2012 summer, as well as muon neutrino disappearance results based on the data coming from the first two years of the experiment.

  19. Recent Results from the T2K Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Abe, K. [University of Tokyo, Institute for Cosmic Ray Research, Kamioka Observatory, Kamioka (Japan); Abgrall, N. [University of Geneva, Section de Physique, DPNC, Geneva (Switzerland); Aihara, H. [University of Tokyo, Department of Physics, Tokyo (Japan); Akiri, T. [Duke University, Department of Physics, Durham, North Carolina (United States); Andreopoulos, C. [STFC, Rutherford Appleton Laboratory, Harwell Oxford, and Daresbury Laboratory, Warrington (United Kingdom); Aoki, S. [Kobe University, Kobe (Japan); Ariga, A.; Ariga, T. [University of Bern, Albert Einstein Center for Fundamental Physics, Laboratory for High Energy Physics (LHEP), Bern (Switzerland); Assylbekov, S. [Colorado State University, Department of Physics, Fort Collins, Colorado (United States); Autiero, D. [Université de Lyon, Université Claude Bernard Lyon 1, IPN Lyon (IN2P3), Villeurbanne (France); Barbi, M. [University of Regina, Department of Physics, Regina, Saskatchewan (Canada); Barker, G.J. [University of Warwick, Department of Physics, Coventry (United Kingdom); Barr, G. [Oxford University, Department of Physics, Oxford (United Kingdom); Bass, M. [Colorado State University, Department of Physics, Fort Collins, Colorado (United States); Batkiewicz, M. [H. Niewodniczanski Institute of Nuclear Physics PAN, Cracow (Poland); Bay, F. [ETH Zurich, Institute for Particle Physics, Zurich (Switzerland); Bentham, S.W. [Lancaster University, Physics Department, Lancaster (United Kingdom); Berardi, V. [INFN Sezione di Bari and Università e Politecnico di Bari, Dipartimento Interuniversitario di Fisica, Bari (Italy); Berger, B.E. [Colorado State University, Department of Physics, Fort Collins, Colorado (United States); Berkman, S. [University of British Columbia, Department of Physics and Astronomy, Vancouver, British Columbia (Canada); and others

    2014-01-15

    The Tokai to Kamioka (T2K) experiment studies neutrino oscillations using a beam of muon neutrinos produced by an accelerator. The neutrinos travel from J-PARC on the east coast of Japan and are detected 295 kilometers further away in the Super-Kamiokande detector. A complex of near detectors located 280 meters away from the neutrino production target is used to better characterize the neutrino beam and reduce systematic uncertainties. The experiment aims at measuring electronic neutrino appearance (ν{sub μ}→ν{sub e} oscillation) to measure the neutrino mixing angle θ{sub 13}, and muon neutrino disappearance to measure the neutrino mixing angle θ{sub 23} and mass splitting |Δm{sub 32}{sup 2}|. We report here electron neutrino appearance results using three years of data, recorded until the 2012 summer, as well as muon neutrino disappearance results based on the data coming from the first two years of the experiment.

  20. The T2K Side Muon Range Detector (SMRD)

    Energy Technology Data Exchange (ETDEWEB)

    Aoki, S. [Kobe University, Department of Physics (Japan); Barr, G. [University of Oxford, Department of Physics, Oxford (United Kingdom); Batkiewicz, M.; Błocki, J. [H. Niewodniczański Institute of Nuclear Physics PAN, Kraków (Poland); Brinson, J.D.; Coleman, W. [Louisiana State University, Department of Physics and Astronomy, Baton Rouge, LA (United States); Dąbrowska, A. [H. Niewodniczański Institute of Nuclear Physics PAN, Kraków (Poland); Danko, I. [University of Pittsburgh, Department of Physics and Astronomy, Pittsburgh, PA (United States); Dziewiecki, M. [Warsaw University of Technology, Institute of Radioelectronics, Warsaw (Poland); Ellison, B. [Louisiana State University, Department of Physics and Astronomy, Baton Rouge, LA (United States); Golyshkin, L. [Institute for Nuclear Research, Moscow (Russian Federation); Gould, R. [Louisiana State University, Department of Physics and Astronomy, Baton Rouge, LA (United States); Hara, T. [Kobe University, Department of Physics (Japan); Haremza, J.; Hartfiel, B. [Louisiana State University, Department of Physics and Astronomy, Baton Rouge, LA (United States); Holeczek, J. [University of Silesia, Institute of Physics, Katowice (Poland); Izmaylov, A.; Khabibullin, M.; Khotjantsev, A. [Institute for Nuclear Research, Moscow (Russian Federation); Kiełczewska, D. [University of Warsaw, Institute of Experimental Physics, Warsaw (Poland); and others

    2013-01-11

    The T2K experiment is a long baseline neutrino oscillation experiment aiming to observe the appearance of ν{sub e} in a ν{sub μ} beam. The ν{sub μ} beam is produced at the Japan Proton Accelerator Research Complex (J-PARC), observed with the 295 km distant Super-Kamiokande Detector and monitored by a suite of near detectors at 280 m from the proton target. The near detectors include a magnetized off-axis detector (ND280) which measures the unoscillated neutrino flux and neutrino cross-sections. The present paper describes the outermost component of ND280 which is a Side Muon Range Detector (SMRD) composed of scintillation counters with embedded wavelength shifting fibers and Multi-Pixel Photon Counter readout. The components, performance and response of the SMRD are presented.

  1. Searches for sterile neutrinos using the T2K off-axis near detector

    CERN Document Server

    Dewhurst, Debra

    2015-01-01

    In the last decades, the results from a number of short-baseline neutrino experiments and the reanalysis of previous reactor experiments with updated antineutrino fluxes suggest some incompatibility with the standard three-neutrino model. A possible solution to these anomalies is the existence of neutrinos that do not interact via the electroweak force, known as sterile neutrinos. The existence of sterile neutrinos can be investigated with the T2K Experiment. Here we present a search for the disappearance of electron neutrinos over a baseline of 280 m using the T2K off-axis near detector. The data analysed corresponds to an exposure of $5.9 \\times 10^{20}$ protons on target. The region $\\sin^2 2 \\theta > 0.2$ and $\\Delta m^2 > 8~\\textrm{eV}^2$ is excluded at 95% CL. We also present an introduction to a new analysis looking for muon neutrino disappearance with the T2K near detector, which is in its early stages but promises to have interesting results in 2015.

  2. Detection of demyelination in multiple sclerosis by analysis of T2* relaxation at 7 T

    Directory of Open Access Journals (Sweden)

    Xiaozhen Li

    2015-01-01

    Full Text Available Multiple sclerosis (MS is a relatively common cause of inflammatory demyelinating lesions of the central nervous system. In an attempt to detect and characterize ongoing demyelination in MS patient brains, we used a novel magnetic resonance imaging (MRI technique, involving the fitting of a three-component model to the T2* relaxation behavior at high-field (7 T. This model allowed estimation of the amount of myelin water (and thus indirectly myelin content, axonal water, and interstitial water. In this study, 25 relapsing–remitting MS patients underwent a 7 T MRI from which 12 gadolinium-enhancing lesions, 61 non-enhancing lesions, and their corresponding contralateral normal appearing white matter (NAWM regions were analyzed. In both enhancing and non-enhancing lesions, the amplitude of myelin water was significantly decreased, and interstitial and axonal water were increased relative to the contralateral NAWM. Longer relaxation time T2* of interstitial and axonal water, and lower frequency shift of axonal water, were also observed in both enhancing and non-enhancing lesions when compared to the contralateral NAWM. No significant difference was found between enhancing lesions and non-enhancing lesions. These findings suggest that the fitting of a three-component model to the T2* decay curve in MS lesions may help to quantify myelin loss.

  3. T2* mapping for articular cartilage assessment: principles, current applications, and future prospects.

    Science.gov (United States)

    Hesper, Tobias; Hosalkar, Harish S; Bittersohl, Daniela; Welsch, Götz H; Krauspe, Rüdiger; Zilkens, Christoph; Bittersohl, Bernd

    2014-10-01

    With advances in joint preservation surgery that are intended to alter the course of osteoarthritis by early intervention, accurate and reliable assessment of the cartilage status is critical. Biochemically sensitive MRI techniques can add robust biomarkers for disease onset and progression, and therefore, could be meaningful assessment tools for the diagnosis and follow-up of cartilage abnormalities. T2* mapping could be a good alternative because it would combine the benefits of biochemical cartilage evaluation with remarkable features including short imaging time and the ability of high-resolution three-dimensional cartilage evaluation-without the need for contrast media administration or special hardware. Several in vitro and in vivo studies, which have elaborated on the potential of cartilage T2* assessment in various cartilage disease patterns and grades of degeneration, have been reported. However, much remains to be understood and certain unresolved questions have become apparent with these studies that are crucial to the further application of this technique. This review summarizes the principles of the technique and current applications of T2* mapping for articular cartilage assessment. Limitations of recent studies are discussed and the potential implications for patient care are presented.

  4. Effect of Exercise on Psychological Well-being in T2DM

    Directory of Open Access Journals (Sweden)

    Farzad Najafipoor

    2011-09-01

    Full Text Available Background: Type 2 diabetic patients (T2DM experience health problems including psychiatric and psychological complications that influence their general health. Since exercise has an additional effect on psychological improvement, we aimed to establish the role of exercise as improvement of psychological problems. Methods: 80 subjects with T2DM were assigned to take exercise for 90 minutes per session, 3 times a week for a period of 4 months. They answered the GHQ-12 questionnaire before and after the study project. Results: Questionnaires were scored by Likert model and entered the statistical analysis. Our findings demonstrate a significant decrease in the mean GHQ-12 scores. [13.39 ± 5.89 to 8.52 ± 5.12 (p < 0.001]. Factor analysis by Graetz's three-factor model suggests that factor I (anxiety and depression associates with more improvement than the other factors.Conclusion: Exercise improves psychological distress in T2DM and results in improved well-being.

  5. T2* mapping for articular cartilage assessment: principles, current applications, and future prospects

    Energy Technology Data Exchange (ETDEWEB)

    Hesper, Tobias; Bittersohl, Daniela; Krauspe, Ruediger; Zilkens, Christoph [University Duesseldorf, Department of Orthopaedics Medical Faculty, Duesseldorf (Germany); Hosalkar, Harish S. [Center of Hip Preservation and Children' s Orthopaedics, San Diego, CA (United States); Welsch, Goetz H. [Medical University of Vienna, MR Center, Department of Radiology, Vienna (Austria); Bittersohl, Bernd [University Duesseldorf, Department of Orthopaedics Medical Faculty, Duesseldorf (Germany); Heinrich-Heine University, Medical School, Department of Orthopaedics, Duesseldorf (Germany)

    2014-10-15

    With advances in joint preservation surgery that are intended to alter the course of osteoarthritis by early intervention, accurate and reliable assessment of the cartilage status is critical. Biochemically sensitive MRI techniques can add robust biomarkers for disease onset and progression, and therefore, could be meaningful assessment tools for the diagnosis and follow-up of cartilage abnormalities. T2* mapping could be a good alternative because it would combine the benefits of biochemical cartilage evaluation with remarkable features including short imaging time and the ability of high-resolution three-dimensional cartilage evaluation - without the need for contrast media administration or special hardware. Several in vitro and in vivo studies, which have elaborated on the potential of cartilage T2* assessment in various cartilage disease patterns and grades of degeneration, have been reported. However, much remains to be understood and certain unresolved questions have become apparent with these studies that are crucial to the further application of this technique. This review summarizes the principles of the technique and current applications of T2* mapping for articular cartilage assessment. Limitations of recent studies are discussed and the potential implications for patient care are presented. (orig.)

  6. Satisfactory surgical outcome of T2 gastric cancer after modified D2 lymphadenectomy.

    Science.gov (United States)

    Zhang, Shupeng; Wu, Liangliang; Wang, Xiaona; Ding, Xuewei; Liang, Han

    2017-04-01

    Though D2 lymphadenectomy has been increasingly regarded as standard surgical procedure for advanced gastric cancer (GC), the modified D2 (D1 + 7, 8a and 9) lymphadenectomy may be more suitable than D2 dissection for T2 stage GC. The purpose of this study is to elucidate whether the surgical outcome of modified D2 lymphadenectomy was comparable to that of standard D2 dissection in T2 stage GC patients. A retrospective cohort study with 77 cases and 77 controls matched for baseline characteristics was conducted. Patients were categorized into two groups according to the extent of lymphadenectomy: the modified D2 group (mD2) and the standard D2 group (D2). Surgical outcome and recurrence date were compared between the two groups. The 5-year overall survival (OS) rate was 71.4% for patients accepted mD2 lymphadenectomy and 70.1% for those accepted standard D2, respectively, and the difference was not statistically significant. Multivariate survival analysis revealed that curability, tumor size, TNM stage and postoperative complications were independently prognostic factors for T2 stage GC patients. Patients in the mD2 group tended to have less intraoperative blood loss (P=0.001) and shorter operation time (PD2 group. While there were no significant differences in recurrence rate and types, especially lymph node recurrence, between the two groups. The surgical outcome of mD2 lymphadenectomy was equal to that of standard D2, and the use of mD2 instead of standard D2 can be a better option for T2 stage GC.

  7. T2MR and T2Candida: novel technology for the rapid diagnosis of candidemia and invasive candidiasis.

    Science.gov (United States)

    Pfaller, Michael A; Wolk, Donna M; Lowery, Thomas J

    2016-01-01

    Candidemia and other forms of invasive candidiasis pose a significant diagnostic challenge. In order to provide the best treatment, it is important to accurately detect the fungal infection and identify the species. Historically, diagnosis of Candida infections depended upon three classical laboratory approaches: microbiologic, immunologic, histopathologic; and now includes new methods such as radiographic techniques, molecular, proteomic and biochemical methods. The T2Candida Panel has introduced a new class of infectious disease diagnostics that can rapidly detect and identify the causative pathogen of sepsis directly from a patient blood sample in a culture-independent manner. This test enables detection of Candida directly from the patient sample, a significant advance for the rapid and accurate diagnosis of invasive candidiasis.

  8. Whole-brain three-dimensional T2-weighted BOLD functional magnetic resonance imaging at 7 Tesla.

    Science.gov (United States)

    Hua, Jun; Qin, Qin; van Zijl, Peter C M; Pekar, James J; Jones, Craig K

    2014-12-01

    A new acquisition scheme for T2-weighted spin-echo BOLD fMRI is introduced. It uses a T2-preparation module to induce blood-oxygenation-level-dependent (BOLD) contrast, followed by a single-shot three-dimensional (3D) fast gradient-echo readout with short echo time (TE). It differs from most spin-echo BOLD sequences in that BOLD contrast is generated before the readout, which eliminates the "dead time" due to long TE required for T2 contrast, and substantially improves acquisition efficiency. This approach, termed "3D T2prep-GRE," was implemented at 7 Tesla (T) with a typical spatial (2.5 × 2.5 × 2.5 mm(3) ) and temporal (TR = 2.3 s) resolution for functional MRI (fMRI) and whole-brain coverage (55 slices), and compared with the widely used 2D spin-echo EPI sequence. In fMRI experiments of simultaneous visual/motor activities, 3D T2prep-GRE showed minimal distortion and little signal dropout across the whole brain. Its lower power deposition allowed greater spatial coverage (55 versus 17 slices with identical TR, resolution and power level), temporal SNR (60% higher) and CNR (35% higher) efficiency than 2D spin-echo EPI. It also showed smaller T2* contamination. This approach is expected to be useful for ultra-high field fMRI, especially for regions near air cavities. The concept of using T2-preparation to generate BOLD contrast can be combined with many other sequences at any field strength. © 2013 Wiley Periodicals, Inc.

  9. Quantitative assessment of the supraspinatus tendon on MRI using T2/T2* mapping and shear-wave ultrasound elastography: a pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Krepkin, Konstantin; Adler, Ronald S.; Gyftopoulos, Soterios [NYU Langone Medical Center/Hospital for Joint Diseases, Department of Radiology, New York, NY (United States); Bruno, Mary; Raya, Jose G. [NYU Langone Medical Center, Center for Biomedical Imaging, Department of Radiology, New York, NY (United States)

    2017-02-15

    To determine whether there is an association between T2/T2* mapping and supraspinatus tendon mechanical properties as assessed by shear-wave ultrasound elastography (SWE). This HIPAA-compliant prospective pilot study received approval from our hospital's institutional review board. Eight patients (3 males/5 females; age range 44-72 years) and nine shoulders underwent conventional shoulder MRI, T2/T2* mapping on a 3-T scanner, and SWE. Two musculoskeletal radiologists reviewed the MRI examinations in consensus for evidence of supraspinatus tendon pathology, with tear size measured for full-thickness tears. T2/T2* values and ultrasound shear-wave velocities (SWV) were calculated in three corresponding equidistant regions of interest (ROIs) within the insertional 1-2 cm of the supraspinatus tendon (medial, middle, lateral). Pearson correlation coefficients between T2/T2* values and SWV, as well as among T2, T2*, SWV and tear size, were calculated. There was a significant negative correlation between T2* and SWV in the lateral ROI (r = -0.86, p = 0.013) and overall mean ROI (r = -0.90, p = 0.006). There was significant positive correlation between T2 and measures of tear size in the lateral and mean ROIs (r range 0.71-0.77, p range 0.016-0.034). There was significant negative correlation between SWV and tear size in the middle and mean ROIs (r range -0.79-0.68, p range 0.011-0.046). Our pilot study demonstrated a potential relationship between T2* values and shear wave velocity values in the supraspinatus tendon, a finding that could lead to an improved, more quantitative evaluation of the rotator cuff tendons. (orig.)

  10. Cardiac MRI. T2-mapping versus T2-weighted dark-blood TSE imaging for myocardial edema visualization in acute myocardial infarction

    Energy Technology Data Exchange (ETDEWEB)

    Nassenstein, K.; Nensa, F.; Schlosser, T.; Umutlu, L.; Lauenstein, T. [University Hospital Essen (Germany). Dept. of Diagnostic and Interventional Radiology and Neuroradiology; Bruder, O. [Elisabeth Hospital, Essen (Germany). Dept. of Cardiology and Angiology; Maderwald, S.; Ladd, M.E. [Duisburg-Essen Univ., Essen (Germany). Erwin L. Hahn Institute for Magnetic Resonance Imaging

    2014-02-15

    Purpose: To assess the diagnostic accuracy of T2 mapping for the detection of myocardial edema in acute myocardial infarction (AMI), and to compare this diagnostic accuracy with that of the current standard for myocardial edema imaging, which is T2w dark-blood TSE imaging. Materials and Methods: 29 patients with AMI were examined at 1.5 T. For the visualization of myocardial edema, T2 maps, calculated from three T2w SSFP images, and T2w dark-blood TSE images were acquired in standard short- and long-axis views. Cine SSFP images were acquired for the analysis of left ventricular (LV) function and late gadolinium enhancement images (LGE) for the visualization of myocardial necrosis. The T2 maps as well as the T2w dark-blood TSE images were evaluated twice independently from the cine SSFP and LGE images. The presence or absence of myocardial edema was rated visually for each LV segment. As the standard of reference, the infarct zone was defined based on the cine SSFP and the LGE images. Results: In this segment-based analysis, T2 mapping showed a sensitivity of 82 % and a specificity of 94 % for the detection of edema in the infarct zone. T2w dark-blood TSE imaging revealed a sensitivity of 50 % and a specificity of 98 %. T2 mapping showed a higher intra-rater agreement compared to T2w dark-blood TSE imaging ({kappa}: 0.87 vs. 0.76). Conclusions: T2 mapping allows for the visualization of myocardial edema in AMI with a high sensitivity and specificity, and features better diagnostic accuracy in terms of a higher sensitivity compared to T2w dark-blood TSE imaging. (orig.)

  11. Quantitative assessment of the supraspinatus tendon on MRI using T2/T2* mapping and shear-wave ultrasound elastography: a pilot study.

    Science.gov (United States)

    Krepkin, Konstantin; Bruno, Mary; Raya, José G; Adler, Ronald S; Gyftopoulos, Soterios

    2017-02-01

    To determine whether there is an association between T2/T2* mapping and supraspinatus tendon mechanical properties as assessed by shear-wave ultrasound elastography (SWE). This HIPAA-compliant prospective pilot study received approval from our hospital's institutional review board. Eight patients (3 males/5 females; age range 44-72 years) and nine shoulders underwent conventional shoulder MRI, T2/T2* mapping on a 3-T scanner, and SWE. Two musculoskeletal radiologists reviewed the MRI examinations in consensus for evidence of supraspinatus tendon pathology, with tear size measured for full-thickness tears. T2/T2* values and ultrasound shear-wave velocities (SWV) were calculated in three corresponding equidistant regions of interest (ROIs) within the insertional 1-2 cm of the supraspinatus tendon (medial, middle, lateral). Pearson correlation coefficients between T2/T2* values and SWV, as well as among T2, T2*, SWV and tear size, were calculated. There was a significant negative correlation between T2* and SWV in the lateral ROI (r = -0.86, p = 0.013) and overall mean ROI (r = -0.90, p = 0.006). There was significant positive correlation between T2 and measures of tear size in the lateral and mean ROIs (r range 0.71-0.77, p range 0.016-0.034). There was significant negative correlation between SWV and tear size in the middle and mean ROIs (r range -0.79--0.68, p range 0.011-0.046). Our pilot study demonstrated a potential relationship between T2* values and shear wave velocity values in the supraspinatus tendon, a finding that could lead to an improved, more quantitative evaluation of the rotator cuff tendons.

  12. Dephasing rate in an InAs/GaAs single-electron quantum dot qubit

    Institute of Scientific and Technical Information of China (English)

    PAN; Liuxian(潘留仙); LI; Shushen(李树深); LIU; Jinlong(刘金龙); NIU; Zhichuan(牛智川); FENG; Songlin(封松林); ZHENG; Houzhi(郑厚植)

    2002-01-01

    We have obtained the parameter-phase diagram, which unambiguously defines the parameter region for the use of InAs/GaAs quantum dot as two-level quantum system in quantum computation in the framework of the effective-mass envelope function theory. Moreover, static electric field is found to efficiently prolong decoherence time. As a result, decoherence time may reach the order of magnitude of milli-seconds as external static electric field goes beyond 20 kV/cm if only vacuum fluctuation is taken as the main source for decoherence. Our calculated results are useful for guiding the solid-state implementation of quantum computing.

  13. Detection of hypoxic-ischemic brain injury with 3D-enhanced T2* weighted angiography (ESWAN) imaging

    Energy Technology Data Exchange (ETDEWEB)

    Gang, QiangQiang, E-mail: rousikang@163.com; Zhang, Jianing, E-mail: 1325916060@qq.com; Hao, Peng, E-mail: 1043600590@qq.com; Xu, Yikai, E-mail: yikaivip@163.com

    2013-11-01

    Objective: To demonstrate the use of 3D-enhanced T2* weighted angiography (ESWAN) imaging for the observation and quantification of the evolution of brain injury induced by a recently developed model of hypoxic-ischemic brain injury (HI/R) in neonatal piglets. Methods: For these experiments, newborn piglets were subjected to HI/R injury, during which ESWAN scanning was performed, followed by H and E staining and immunohistochemistry of AQP-4 expression. Results: In the striatum, values from T2* weighted magnetic resonance imaging (MRI) increased and reached their highest level at 3 days post injury, whereas T2* values increased and peaked at 24 h in the subcortical region. The change in T2* values was concordant with brain edema. Phase values in the subcortical border region were not dependent on time post-injury. Magnitude values were significantly different from the control group, and increased gradually over time in the subcortical border region. Susceptibility-weighted images (SWI) indicated small petechial hemorrhages in the striatum and thalamus, as well as dilated intramedullary veins. Conclusion: SWI images can be used to detect white and gray matter microhemorrhages and dilated intramedullary veins. The T2*, phase, and magnitude map can also reflect the development of brain injury. Our data illustrate that ESWAN imaging can increase the diagnostic sensitivity and specificity of MRI in neonatal hypoxic-ischemic encephalopathy.

  14. On designing of the driven system control of solar panels using type 2 fuzzy sliding mode control (T2FSMC)

    Science.gov (United States)

    Mardlijah, Subiono, S., Sentot D.; Efprianto, Yahya

    2016-02-01

    Collectors on the solar panel can work optimally when the collectors position perpendicular to the whole solar rays. Therefore we need a control system to control the position of the collectors always perpendicular to the sun rays. In this paper, control system T2FSMC is proposed, combined SMC, FLC and fuzzy type 2 which has a membership function more complex so as to provide an additional degree of freedom that allows uncertainty. the behavior of the control system based on T2FSMC for the driven system of solar panels was analyzed by comparing T2FSMC with FSMC and SMC methods. It can be concluded that the system controller of T2FSMC works better than the system controller of FSMC and SMC; i.e. faster response time, more robust to large and small disturbance and more robust to parameter uncertainty. However, the lacks in the system T2FSMC are taking quite a long time in computation and need fuzzy logic reasoning.

  15. Chicken Cytochrome P450 1A5 Is the Key Enzyme for Metabolizing T-2 Toxin to 3'OH-T-2

    Directory of Open Access Journals (Sweden)

    Shufeng Shang

    2013-05-01

    Full Text Available The transmission of T-2 toxin and its metabolites into the edible tissues of poultry has potential effects on human health. We report that T-2 toxin significantly induces CYP1A4 and CYP1A5 expression in chicken embryonic hepatocyte cells. The enzyme activity assays of CYP1A4 and CYP1A5 heterologously expressed in HeLa cells indicate that only CYP1A5 metabolizes T-2 to 3'OH-T-2 by the 3'-hydroxylation of isovaleryl groups. In vitro enzyme assays of recombinant CYP1A5 expressed in DH5α further confirm that CYP1A5 can convert T-2 into TC-1 (3'OH-T-2. Therefore, CYP1A5 is critical for the metabolism of trichothecene mycotoxin in chickens.

  16. Dynamics of unloaded and green tea extract loaded lecithin based liposomal dispersions investigated by nuclear magnetic resonance T2 relaxation.

    Science.gov (United States)

    Kirtil, Emrah; Dag, Damla; Guner, Selen; Unal, Kubra; Oztop, Mecit H

    2017-09-01

    Liposomes are lipid bilayer vesicles that can be used as encapsulation systems for bioactive agents to provide increased protection against environmental stresses (such as pH or temperature extremes). Time Domain Nuclear Magnetic Resonance (TD-NMR) that is based on differentiation of specimen contents with respect to magnetic relaxation rates provides detailed information on amount, state and distribution of water and oil and provide reproducible results on the samples. These make TD-NMR particularly suitable for time-dependent monitoring of emulsion system dynamics. In this study, spin-spin (T2) relaxation times and relaxation spectra were used for characterizing green tea extract loaded and unloaded liposomes prepared with soy (S75) and egg lecithins (E80) by different preparation methods (such as homogenization type, pressure and solvent type). Mean particle sizes of liposomes were found to be the most influential factor in shaping mono-exponential T2 relaxation times. The differences in particle sizes of E80 and S75 samples along with samples with different homogenization pressures could be monitored with T2 relaxation times. Additionally, T2 relaxation times were found to be correlated with particle shape irregularity, and chemical instability of samples due to lipid oxidation. With relaxation spectrum analysis, particular components in the sample could be distinguished (internal/external water and lipid bilayers), which gave more elaborate results on mechanisms of instability. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. The T2K fine-grained detectors

    Energy Technology Data Exchange (ETDEWEB)

    Amaudruz, P.-A. [TRIUMF, Vancouver, British Columbia (Canada); Barbi, M. [University of Regina, Physics Department, Regina, Saskatchewan (Canada); Bishop, D. [TRIUMF, Vancouver, British Columbia (Canada); Braam, N. [University of Victoria, Department of Physics and Astronomy, Victoria, British Columbia (Canada); Brook-Roberge, D.G. [University of British Columbia, Department of Physics and Astronomy, Vancouver, British Columbia (Canada); Giffin, S. [University of Regina, Physics Department, Regina, Saskatchewan (Canada); Gomi, S. [Kyoto University, Department of Physics, Kyoto (Japan); Gumplinger, P.; Hamano, K. [TRIUMF, Vancouver, British Columbia (Canada); Hastings, N.C. [University of Regina, Physics Department, Regina, Saskatchewan (Canada); Hastings, S. [University of British Columbia, Department of Physics and Astronomy, Vancouver, British Columbia (Canada); Helmer, R.L., E-mail: helmer@triumf.ca [TRIUMF, Vancouver, British Columbia (Canada); Henderson, R. [TRIUMF, Vancouver, British Columbia (Canada); Ieki, K. [Kyoto University, Department of Physics, Kyoto (Japan); Jamieson, B. [University of British Columbia, Department of Physics and Astronomy, Vancouver, British Columbia (Canada); Kato, I.; Khan, N. [TRIUMF, Vancouver, British Columbia (Canada); Kim, J.; Kirby, B. [University of British Columbia, Department of Physics and Astronomy, Vancouver, British Columbia (Canada); Kitching, P. [University of Alberta, Centre for Particle Physics, Department of Physics, Edmonton, Alberta (Canada); and others

    2012-12-22

    T2K is a long-baseline neutrino oscillation experiment searching for {nu}{sub e} appearance in a {nu}{sub {mu}} beam. The beam is produced at the J-PARC accelerator complex in Tokai, Japan, and the neutrinos are detected by the Super-Kamiokande detector located 295 km away in Kamioka. A suite of near detectors (ND280) located 280 m downstream of the production target is used to characterize the components of the beam before they have had a chance to oscillate and to better understand various neutrino interactions on several nuclei. This paper describes the design and construction of two massive fine-grained detectors (FGDs) that serve as active targets in the ND280 tracker. One FGD is composed solely of scintillator bars while the other is partly scintillator and partly water. Each element of the FGDs is described, including the wavelength shifting fiber and Multi-Pixel Photon Counter used to collect the light signals, the readout electronics, and the calibration system. Initial tests and in situ results of the FGDs' performance are also presented.

  18. Towards MRI T2 contrast agents of increased efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Branca, Marlène [CNRS, LCC (Laboratoire de Chimie de Coordination), 205, route de Narbonne, F-31077 Toulouse (France); Université de Toulouse, UPS, INPT, LCC, F-31077 Toulouse (France); Marciello, Marzia, E-mail: marziamarciello@icmm.csic.es [Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049 Madrid (Spain); Ciuculescu-Pradines, Diana [CNRS, LCC (Laboratoire de Chimie de Coordination), 205, route de Narbonne, F-31077 Toulouse (France); Université de Toulouse, UPS, INPT, LCC, F-31077 Toulouse (France); Respaud, Marc [LPCNO, INSA, 135 Avenue de Rangueil, 31077 Toulouse Cedex 4 (France); Morales, Maria del Puerto [Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049 Madrid (Spain); Serra, Raphael; Casanove, Marie-José [CNRS, CEMES (Centre d' Elaboration des Matériaux et d' Etudes Structurales) (France); Amiens, Catherine, E-mail: catherine.amiens@lcc-toulouse.fr [CNRS, LCC (Laboratoire de Chimie de Coordination), 205, route de Narbonne, F-31077 Toulouse (France); Université de Toulouse, UPS, INPT, LCC, F-31077 Toulouse (France)

    2015-03-01

    Magnetic nanoparticles can be efficient contrast agents for T2 weighted magnetic resonance imaging (MRI) after tuning of some key parameters such as size, surface state, colloidal stability and magnetization, thus motivating the development of new synthetic pathways. In this paper we report the effects of surface coating on the efficiency of two different types of iron based nanoparticles (NPs) as MRI contrast agents. Starting from well-defined hydrophobic iron oxide nanospheres and iron nanocubes of 13 nm size, we have used three methods to increase their hydrophilicity and transfer them into water: surface ligand modification, ligand exchange or encapsulation. The NPs obtained have been characterized by dynamic light scattering and transmission electron microscopy, and the relaxivities of their stable colloidal solutions in water have been determined. Among all samples prepared, iron nanocubes coated by silica display the highest relaxivity (r{sub 2}) value: 628 s{sup −1} mM{sup −1}. - Highlights: • Surface coating effect on the efficiency of iron based nanoparticles (NPs) as MRI contrast agents. • Synthesis of 2 different types of hydrophobic iron based NPs: iron oxide nanospheres and iron nanocubes (13 nm). • Development of three different procedures to stabilize iron based NPs in water. • Iron nanocubes coated by silica displayed the highest r{sub 2} value (628 s{sup −1} mM{sup −1})

  19. T2 mapping with magnetization-prepared 3D TSE based on a modified BIR-4 T2 preparation.

    Science.gov (United States)

    Weidlich, Dominik; Schlaeger, Sarah; Kooijman, Hendrik; Börnert, Peter; Kirschke, Jan S; Rummeny, Ernst J; Haase, Axel; Karampinos, Dimitrios C

    2017-08-04

    The purpose of this work was to investigate the performance of the modified BIR-4 T2 preparation for T2 mapping and propose a method to remove T2 quantification errors in the presence of large B1 and B0 offsets. The theoretical investigation of the magnetization evolution during the T2 preparation in the presence of B1 and B0 offsets showed deviations from a mono-exponential T2 decay (two parameter fit). A three parameter fit was used to improve T2 accuracy. Furthermore, a two parameter fit with an additional saturation preparation scan was proposed to improve T2 accuracy and precision. These three fitting methods were compared based on simulations, phantom measurements and an in vivo healthy volunteer study of the neck musculature using a 3D TSE readout. The results based upon the pure two parameter fit overestimated T2 in regions with high B0 offsets (up to 40% in phantoms). The three parameter fit T2 values were robust to B0 offsets but with higher standard deviation (up to 40% in simulations). The two parameter fit with the saturation preparation yielded high robustness towards B0 offsets with a noise performance comparable to that of the two parameter fit. In the volunteer study the T2 values obtained by the pure two parameter fit showed a dependence on the field inhomogeneities, whereas the T2 values from the proposed fitting approach were shown to be insensitive to B0 offsets. The proposed method enabled accurate and precise T2 mapping in the presence of large B1 and B0 offsets. Copyright © 2017 John Wiley & Sons, Ltd.

  20. MR imaging findings of diffuse axonal injury: comparison of T2-weighted gradient images and T1- and T2-weighted spin-echo images

    Energy Technology Data Exchange (ETDEWEB)

    Park, Seo Young; Lee, Ghi Jai; Kim, Jeong Seok; Shim, Jae Chan; Kim, Ho Kyun [Inje Univ. College of Medicine, Seoul (Korea, Republic of)

    1998-10-01

    To compare T2-weighted images with spin-echo T1- and turbo spin-echo (TSE) T2-weighted images in patients with diffuse axonal injury(DAI). Using a 1.0T MR unit, SE T1-, TSE T2-, and and FLASH T2-weighted images were obtained from 69 patients with a history of head trauma. In 18MR images of 17 patients with imaging findings of DAI, T2-weighted images were retrospectively compared with SE T1- and TSE T2-weighted images. The interval between trauma and MR scan varied from 5 days to 24(mean, 11) months. Focusing on the number of lesions, and their location and signal intensity, as weel as associated findings, three images were simultaueously evaluated. In 18 MR images of 17 patients with MR imaging findings of DAI, 21 lesions were detected on T1-weighted images, 28 on TSE T2-weighted images, and 70 on T2-weighted images;the last of these revealed all lesions detected on the other two. Most lesions were hypointense on T1-weighted images(17/21), hyperintense on TSE T2-weighted (21/28), and hypointense on T2-weighted (63/70). Common locations for DAI were the frontal lobe (n=3D35) and corpus callosum (n=3D22). Associated brain injuries were cortical contusion (n=3D5), brainstem injury (n=3D3), deep gray matter injury (n=3D2), and subdural hematoma(n=3D1). In patients with DAI. T2-weighted images can detect more lesions and associated petechial hemorrhage than can TSE T2-weighted images. This modality is thus useful for the evaluation of patients with head trauma.=20.

  1. Semi-automatic segmentation of myocardium at risk in T2-weighted cardiovascular magnetic resonance

    Directory of Open Access Journals (Sweden)

    Sjögren Jane

    2012-01-01

    Full Text Available Abstract Background T2-weighted cardiovascular magnetic resonance (CMR has been shown to be a promising technique for determination of ischemic myocardium, referred to as myocardium at risk (MaR, after an acute coronary event. Quantification of MaR in T2-weighted CMR has been proposed to be performed by manual delineation or the threshold methods of two standard deviations from remote (2SD, full width half maximum intensity (FWHM or Otsu. However, manual delineation is subjective and threshold methods have inherent limitations related to threshold definition and lack of a priori information about cardiac anatomy and physiology. Therefore, the aim of this study was to develop an automatic segmentation algorithm for quantification of MaR using anatomical a priori information. Methods Forty-seven patients with first-time acute ST-elevation myocardial infarction underwent T2-weighted CMR within 1 week after admission. Endocardial and epicardial borders of the left ventricle, as well as the hyper enhanced MaR regions were manually delineated by experienced observers and used as reference method. A new automatic segmentation algorithm, called Segment MaR, defines the MaR region as the continuous region most probable of being MaR, by estimating the intensities of normal myocardium and MaR with an expectation maximization algorithm and restricting the MaR region by an a priori model of the maximal extent for the user defined culprit artery. The segmentation by Segment MaR was compared against inter observer variability of manual delineation and the threshold methods of 2SD, FWHM and Otsu. Results MaR was 32.9 ± 10.9% of left ventricular mass (LVM when assessed by the reference observer and 31.0 ± 8.8% of LVM assessed by Segment MaR. The bias and correlation was, -1.9 ± 6.4% of LVM, R = 0.81 (p Conclusions There is a good agreement between automatic Segment MaR and manually assessed MaR in T2-weighted CMR. Thus, the proposed algorithm seems to be a

  2. Assessment of Heart and Liver Iron Overload in Thalassemia Major Patients Using T2* Magnetic Resonance Imaging.

    Science.gov (United States)

    Farhangi, Hamid; Badiei, Zahra; Moghaddam, Hasan Mottaghi; Keramati, Mohammad Reza

    2017-06-01

    Accumulation of excess iron in heart can lead to cardiac dysfunction, which is the most common cause of death in thalassemia major patients. Biopsy is an invasive procedure and therefore not an ideal option to assess iron load. However, standard/usual non-invasive methods, such as ferritin measurement, have some limitations and the results show poor correlations with iron load. Magnetic Response Imaging (MRI-T2*), as a non-invasive and reliable method for iron load assessment in organs such as liver and heart, can be suggested as a favorable alternative. This cross-sectional study was implemented in Thalassemia and Hemophilia Clinic Center (Sarvar) affiliated with Mashhad University of Medical Sciences, Mashhad, Iran, from 2012 to 2013. After the approval of the research protocol by the local ethic committee, laboratory tests, including CBC and serum ferritin, were carried out, and echocardiography and heart and liver MRI-T2* were performed. All statistical analysis was done through SPSS software (version 11.5), using independent sample t test and Pearson's correlation coefficient test. A P value ≤0.05 was considered to be significant. 88 patients with the mean (±SD) age of 21.2 (±5.6) years, (range 11-37 years) were observed. Iron load was assessed using MRI-T2* with the following results: Out of 88 patients, 48.9 % had mild to severe cardiac siderosis, and 75.2 % had mild to severe liver siderosis. We demonstrated a correlation between liver MRI-T2* and serum ferritin, and heart MRI-T2* and ejection fraction. However, no correlation between liver and heart MRI-T2* was observed. Heart and liver siderosis is a common and serious problem in thalassemia major patients, and MRI-T2* as a sensitive and non-invasive technique can be used for early/timely detection of siderosis and good therapeutic monitoring in these patients.

  3. Sequential change in T2* values of cartilage, meniscus, and subchondral bone marrow in a rat model of knee osteoarthritis.

    Directory of Open Access Journals (Sweden)

    Ping-Huei Tsai

    Full Text Available BACKGROUND: There is an emerging interest in using magnetic resonance imaging (MRI T2* measurement for the evaluation of degenerative cartilage in osteoarthritis (OA. However, relatively few studies have addressed OA-related changes in adjacent knee structures. This study used MRI T2* measurement to investigate sequential changes in knee cartilage, meniscus, and subchondral bone marrow in a rat OA model induced by anterior cruciate ligament transection (ACLX. MATERIALS AND METHODS: Eighteen male Sprague Dawley rats were randomly separated into three groups (n = 6 each group. Group 1 was the normal control group. Groups 2 and 3 received ACLX and sham-ACLX, respectively, of the right knee. T2* values were measured in the knee cartilage, the meniscus, and femoral subchondral bone marrow of all rats at 0, 4, 13, and 18 weeks after surgery. RESULTS: Cartilage T2* values were significantly higher at 4, 13, and 18 weeks postoperatively in rats of the ACLX group than in rats of the control and sham groups (p<0.001. In the ACLX group (compared to the sham and control groups, T2* values increased significantly first in the posterior horn of the medial meniscus at 4 weeks (p = 0.001, then in the anterior horn of the medial meniscus at 13 weeks (p<0.001, and began to increase significantly in the femoral subchondral bone marrow at 13 weeks (p = 0.043. CONCLUSION: Quantitative MR T2* measurements of OA-related tissues are feasible. Sequential change in T2* over time in cartilage, meniscus, and subchondral bone marrow were documented. This information could be potentially useful for in vivo monitoring of disease progression.

  4. Measuring neutrino-induced exclusive charge-current final states on hydrogen at T2K

    CERN Document Server

    Coplowe, David; Barr, Giles

    2016-01-01

    By taking advantage of symmetries with respect to the plane containing the directions of the neutrino and outgoing lepton, it is possible to isolate neutrino interactions on hydrogen in composite nuclear targets. This technique enables us to study the `primary' neutrino-nucleon interaction and therefore gain access to fundamental model parameters free from nuclear effects. Using T2K Monte Carlo equivalent to $\\sim7\\times10^{21}$ POT, we present an update on the measurement of the exclusive charged-current $\\mu^-$, p, $\\pi^+$ final state on hydrogen.

  5. Isolated symmetrical bilateral basal ganglia T2 hyperintensity in carbon monoxide poisoning

    Directory of Open Access Journals (Sweden)

    Subhaschandra S

    2008-01-01

    Full Text Available Carbon monoxide poisoning is not uncommon during the winter months. To make a diagnosis, strong clinical suspicion and acumen, and history of the exposure are necessary. Many a time, the presenting complaints may fail to help reach a diagnosis, in the absence of history. Imaging plays a role in the diagnosis of brain injury with the characteristic features, which are correlated with the clinical profile. Isolated bilateral basal ganglia injury revealing T2 hyperintensity in MRI may be observed in acute carbon monoxide poisoning.

  6. First opportunity to synchronize the ILRS network thanks to T2L2 on Jason-2

    Science.gov (United States)

    Exertier, Pierre; Belli, Alexandre; Courde, Clément; Vernotte, François

    2016-07-01

    The Time Transfer by Laser Link (T2L2, on-board the oceanographic satellite Jason-2 at 1335 km) experiment allows us to synchronize remote clocks of Satellite Laser Ranging (SLR) stations throughout the whole ILRS (International Laser Ranging Service) network. We have developed a time transfer processing dedicated to non Common View (CV) cases, i.e. time transfer between stations from the Americas, Asia, Europe and Oceania. The main difficulty is to take into account the complex behaviour of the on-board Ultra Stable Oscillator (USO) over more than 1,500 s and up to a few thousands seconds. By integrating a recently published model describing the frequency responses of the USO to physical effects, as temperature and radiations, we show that it is possible to propagate the phase (time) of the on-board clock for an orbital revolution (1 rev = 6,700 s) or two with an error of a few nanoseconds (ns). Scheme of stages of this process is presented. The non CV time transfer process is applied in order to synchronize a plurality of remote stations involved in the T2L2/Jason-2 tracking by laser. The ground-to-space time transfers which we have processed over recent years (from 2013 to 2015) are all contributing to the development of a synthetic on-board time scale. The resulting ground-to-ground time transfers, computed between remote clocks of SLR stations, show differences of 250-300 ns up to a few microseconds ± 3-4 ns. The T2L2 space experiment is thus the first opportunity to estimate, quasi-instantaneously and to the ns level, time differences between clocks of the SLR stations which form one of the basis of the International Terrestrial Reference Frame (ITRF). This result would help the laser ranging community (time & frequency metrology of stations, analysis centres, and applications to the precise orbit and positioning) to achieve the GGOS (Global Geodetic Observing System) requirements in terms of accuracy and long-term stability of geodetic references.

  7. T2K Replica Target Hadron Production Measurements in NA61/SHINE and T2K Neutrino Flux Predictions

    CERN Document Server

    AUTHOR|(SzGeCERN)710687

    Accelerator based neutrino experiments generate their neutrino beams by impinging high energy protons on thick targets. The neutrino beam predictions are thus based on modeling the interactions of the beam protons inside the targets. Different hadronic models can be used with different accuracies depending on the energy range of the incident protons and on the target material. Nevertheless, none of the models can be seen as perfectly describing all different interactions. In order to reach high precision neutrino flux predictions, it is thus mandatory to be able to test and constrain the models with hadron production measurements. The T2K experiment in Japan uses the ancillary NA61/SHINE facility at CERN to constrain the production of hadrons resulting from the interactions of proton beam particles impinging on a 90cm long graphite target. Data taken by NA61/SHINE with a 30 GeV proton beam on a thin (4% interaction length) graphite target have been recorded in 2007 and 2009. They have been analysed and extens...

  8. Computer-aided diagnosis of early knee osteoarthritis based on MRI T2 mapping.

    Science.gov (United States)

    Wu, Yixiao; Yang, Ran; Jia, Sen; Li, Zhanjun; Zhou, Zhiyang; Lou, Ting

    2014-01-01

    This work was aimed at studying the method of computer-aided diagnosis of early knee OA (OA: osteoarthritis). Based on the technique of MRI (MRI: Magnetic Resonance Imaging) T2 Mapping, through computer image processing, feature extraction, calculation and analysis via constructing a classifier, an effective computer-aided diagnosis method for knee OA was created to assist doctors in their accurate, timely and convenient detection of potential risk of OA. In order to evaluate this method, a total of 1380 data from the MRI images of 46 samples of knee joints were collected. These data were then modeled through linear regression on an offline general platform by the use of the ImageJ software, and a map of the physical parameter T2 was reconstructed. After the image processing, the T2 values of ten regions in the WORMS (WORMS: Whole-organ Magnetic Resonance Imaging Score) areas of the articular cartilage were extracted to be used as the eigenvalues in data mining. Then,a RBF (RBF: Radical Basis Function) network classifier was built to classify and identify the collected data. The classifier exhibited a final identification accuracy of 75%, indicating a good result of assisting diagnosis. Since the knee OA classifier constituted by a weights-directly-determined RBF neural network didn't require any iteration, our results demonstrated that the optimal weights, appropriate center and variance could be yielded through simple procedures. Furthermore, the accuracy for both the training samples and the testing samples from the normal group could reach 100%. Finally, the classifier was superior both in time efficiency and classification performance to the frequently used classifiers based on iterative learning. Thus it was suitable to be used as an aid to computer-aided diagnosis of early knee OA.

  9. SU-E-J-233: Effect of Brachytherapy Seed Artifacts in T2 and Proton Density Maps in MR Images

    Energy Technology Data Exchange (ETDEWEB)

    Mashouf, S [Sunnybrook Odette Cancer Centre, Toronto, Ontario (Canada); University of Toronto, Dept of Radiation Oncology, Toronto, Ontario (Canada); Fatemi-Ardekani, A [Sunnybrook Odette Cancer Centre, Toronto, Ontario (Canada); Sunnybrook Research Institute, Toronto, Ontario (Canada); Song, W [Sunnybrook Odette Cancer Centre, Toronto, Ontario (Canada); University of Toronto, Dept of Radiation Oncology, Toronto, Ontario (Canada); Sunnybrook Research Institute, Toronto, Ontario (Canada)

    2015-06-15

    Purpose: This study aims at investigating the influence of brachytherapy seeds on T2 and proton density (PD) maps generated from MR images. Proton density maps can be used to extract water content. Since dose absorbed in tissue surrounding low energy brachytherapy seeds are highly influenced by tissue composition, knowing the water content is a first step towards implementing a heterogeneity correction algorithm using MR images. Methods: An LDR brachytherapy (IsoAid Advantage Pd-103) seed was placed in the middle of an agar-based gel phantom and imaged using a 3T Philips MR scanner with a 168-channel head coil. A multiple echo sequence with TE=20, 40, 60, 80, 100 (ms) with large repetition time (TR=6259ms) was used to extract T2 and PD maps. Results: Seed artifacts were considerably reduced on T2 maps compared to PD maps. The variation of PD around the mean was obtained as −97% to 125% (±1%) while for T2 it was recorded as −71% to 24% (±1%). Conclusion: PD maps which are required for heterogeneity corrections are susceptible to artifacts from seeds. Seed artifacts on T2 maps, however, are significantly reduced due to not being sensitive to B0 field variation.

  10. Myocardial area at risk and salvage measured by T2-weighted cardiovascular magnetic resonance: reproducibility and comparison of two T2-weighted protocols

    DEFF Research Database (Denmark)

    Lønborg, Jacob; Vejlstrup, Niels; Mathiasen, Anders B

    2011-01-01

    Late gadolinium enhancement (LGE) and T2-weighted cardiovascular magnetic resonance (CMR) provides a means to measure myocardial area at risk (AAR) and salvage. Several T2-weighted CMR sequences are in use, but there is no consensus in terms of which sequence to be the preferred. Therefore, the aim...

  11. Comparison of ESWAN, SWI-SPGR, and 2D T2*-weighted GRE sequence for depicting cerebral microbleeds.

    Science.gov (United States)

    Guo, L F; Wang, G; Zhu, X Y; Liu, C; Cui, L

    2013-06-01

    We aimed to compare images obtained with an Enhanced 3D multi-echo GRE T2*-weighted angiography (ESWAN) sequence with those obtained with a susceptibility-weighted imaging-spoiled gradient-recalled echo (SWI-SPGR) sequence and a two-dimensional (2D) T2*-weighted gradient-recalled echo (GRE) sequence for the description of cerebral microbleeds (CMBs) in hypertensive patients (elderly people). A total of 273 elderly hypertensive patients were imaged in a 3.0-T MR scanner using ESWAN, SWI-SPGR, and 2D T2*-weighted GRE sequence, respectively. The presence, number, and location of CMBs and scanning and postprocessing time were recorded for both sequences, and the differences were tested using nonparametric McNemar and Friedman tests. CMBs were detected by 2D T2*-weighted GRE images in 54 participants, SWI-SPGR images in 83 participants, and ESWAN images in 88 participants. The participants with CMBs detected by 2D T2*-weighted GRE sequence were fewer than those with CMBs detected by SWI-SPGR or ESWAN sequences (P CMBs in number (P > 0.05). Among the participants with CMBs visualized in both sequences, most patients had CMBs in the subcortical white matter and at deep locations. The participants who had CMBs in the infratentorial region were fewer. The acquisition time of ESWAN images was slightly longer than that of SWI-SPGR images. ESWAN sequence was not superior to SWI-SPGR sequence in depicting CMBs at 3.0-T MR, but both of these sequences were superior to 2D T2*-weighted GRE sequence.

  12. Under which conditions does T1 difficulty affect T2 performance in the attentional blink?

    DEFF Research Database (Denmark)

    Nielsen, Simon; Petersen, Anders; Andersen, Tobias Søren

    When two visual targets (T1 & T2) are presented in rapid succession, performance of T2 suffers up to 900 ms. One theory of this attentional blink (Raymond, Shapiro, & Arnell, 1992) propose that T1 and T2 compete for limited processing resources (Chun & Potter, 1995), and predict that prolonging...

  13. T2-relaxometry predicts outcome of DBS in idiopathic Parkinson's disease

    Directory of Open Access Journals (Sweden)

    Tarja Lönnfors-Weitzel, MD

    2016-01-01

    Conclusions: The lower boundaries of T2r in the STN predict motor outcome in DBS. T2r asymmetry in the STN is not associated with increased clinical symptoms, but with response to therapy. Thus, patients with very low T2r may be inappropriate candidates for DBS.

  14. Anomericity of T-2 toxin-glucoside: masked mycotoxin in cereal crops.

    Science.gov (United States)

    McCormick, Susan P; Kato, Takayuki; Maragos, Chris M; Busman, Mark; Lattanzio, Veronica M T; Galaverna, Gianni; Dall-Asta, Chiara; Crich, David; Price, Neil P J; Kurtzman, Cletus P

    2015-01-21

    T-2 toxin is a trichothecene mycotoxin produced when Fusarium fungi infect grains, especially oats and wheat. Ingestion of T-2 toxin contaminated grain can cause diarrhea, hemorrhaging, and feed refusal in livestock. Cereal crops infected with mycotoxin-producing fungi form toxin glycosides, sometimes called masked mycotoxins, which are a potential food safety concern because they are not detectable by standard approaches and may be converted back to the parent toxin during digestion or food processing. The work reported here addresses four aspects of T-2 toxin-glucosides: phytotoxicity, stability after ingestion, antibody detection, and the anomericity of the naturally occurring T-2 toxin-glucoside found in cereal plants. T-2 toxin-β-glucoside was chemically synthesized and compared to T-2 toxin-α-glucoside prepared with Blastobotrys muscicola cultures and the T-2 toxin-glucoside found in naturally contaminated oats and wheat. The anomeric forms were separated chromatographically and differ in both NMR and mass spectrometry. Both anomers were significantly degraded to T-2 toxin and HT-2 toxin under conditions that mimic human digestion, but with different kinetics and metabolic end products. The naturally occurring T-2 toxin-glucoside from plants was found to be identical to T-2 toxin-α-glucoside prepared with B. muscicola. An antibody test for the detection of T-2 toxin was not effective for the detection of T-2 toxin-α-glucoside. This anomer was produced in sufficient quantity to assess its animal toxicity.

  15. Signal intensity in T2' magnetic resonance imaging is related to brain glioma grade

    Energy Technology Data Exchange (ETDEWEB)

    Saitta, Laura; Castellan, Lucio [San Martino Hospital, Department of Diagnostic and Interventional Neuroradiology, Genoa (Italy); Heese, Oliver; Westphal, Manfred [UKE, Department of Neurosurgery, Hamburg (Germany); Foerster, Ann-Freya; Siemonsen, Susanne; Fiehler, Jens; Goebell, Einar [University Medical Center Hamburg-Eppendorf (UKE), Department of Diagnostic and Interventional Neuroradiology, Hamburg (Germany); Matschke, Jakob [UKE, Department of Neuropathology, Hamburg (Germany)

    2011-05-15

    T2' values reflect the presence of deoxyhaemoglobin related to high local oxygen extraction. We assessed the feasibility of T2' imaging to display regions with high metabolic activity in brain gliomas. MRI was performed in 25 patients (12 female; median age 46 years; range 2-69) with brain gliomas with additional T2 and T2* sequences. T2' maps were derived from T2 and T2*. Dynamic susceptibility weighted contrast (DSC) perfusion was performed in 12/25 patients. Images were visually assessed by two readers and five ROIs were evaluated for each patient. Pearson correlation, Mann-Whitney and Kruskal-Wallis tests were applied for statistical analysis. Three patients were not further evaluated because of artefacts. Mean values of high-grade (III-IV) gliomas showed significantly lower T2' values than low-grade (II) gliomas (p < 0.001). An inverse relationship was observed between rCBV and sqr (T2') (r = -0.463, p < 0.001). No correlation was observed between T2' and rCBV for grade II tumours (r = 0.038; p = 0.875). High-grade tumours revealed lower T2' values, presumably because of higher oxygen consumption in proliferating tissue. Our results indicate that T2' imaging can be used as an alternative to DSC perfusion in the detection of subtle deviations in tumour metabolism. (orig.)

  16. An in vitro comparative study of T2 and T2* mappings of human articular cartilage at 3-Tesla MRI using histology as the standard of reference

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Taehee; Park, Sunghoon [Ajou University School of Medicine, Department of Radiology, Suwon (Korea, Republic of); Ajou University Medical Center, Musculoskeletal Imaging Laboratory, Suwon (Korea, Republic of); Min, Byoung-Hyun [Ajou University School of Medicine, Department of Orthopaedic Surgery, Suwon (Korea, Republic of); Ajou University School of Medicine, Cartilage Regeneration Center, Suwon (Korea, Republic of); Yoon, Seung-Hyun [Ajou University School of Medicine, Cartilage Regeneration Center, Suwon (Korea, Republic of); Kim, Hakil [INHA University, School of Information and Communication Engineering, Incheon (Korea, Republic of); Lee, Hyun Young [Ajou University Medical Center, Regional Clinical Trial Center, Suwon (Korea, Republic of); Yonsei University College of Medicine, Department of Biostatistics, Seoul (Korea, Republic of); Kwack, Kyu-Sung [Ajou University School of Medicine, Department of Radiology, Suwon (Korea, Republic of); Ajou University Medical Center, Musculoskeletal Imaging Laboratory, Suwon (Korea, Republic of); Ajou University School of Medicine, Cartilage Regeneration Center, Suwon (Korea, Republic of)

    2014-07-15

    The aim of this study was to evaluate the correlations between T2 value, T2* value, and histological grades of degenerated human articular cartilage. T2 mapping and T2* mapping of nine tibial osteochondral specimens were obtained using a 3-T MRI after total knee arthroplasty. A total of 94 ROIs were analyzed. Histological grades were assessed using the David-Vaudey scale. Spearman's rho correlation analysis and Pearson's correlation analysis were performed. The mean relaxation values in T2 map with different histological grades (0, 1, 2) of the cartilage were 51.9 ± 9.2 ms, 55.8 ± 12.8 ms, and 59.6 ± 10.2 ms, respectively. The mean relaxation values in T2* map with different histological grades (0, 1, 2) of the cartilage were 20.3 ± 10.3 ms, 21.1 ± 12.4 ms, and 15.4 ± 8.5 ms, respectively. Spearman's rho correlation analysis confirmed a positive correlation between T2 value and histological grade (ρ = 0.313, p < 0.05). Pearson's correlation analysis revealed a significant negative correlation between T2 and T2* (r = -0.322, p < 0.05). Although T2* values showed a decreasing trend with an increase in cartilage degeneration, this correlation was not statistically significant in this study (ρ = -0.192, p = 0.129). T2 mapping was correlated with histological degeneration, and it may be a good biomarker for osteoarthritis in human articular cartilage. However, the strength of the correlation was weak (ρ = 0.313). Although T2* values showed a decreasing trend with an increase in cartilage degeneration, the correlation was not statistically significant. Therefore, T2 mapping may be more appropriate for the initial diagnosis of articular cartilage degeneration in the knee joint. Further studies on T2* mapping are needed to confirm its reliability and mechanism in cartilage degeneration. (orig.)

  17. T-2毒素致胎儿软骨细胞凋亡的观察%Effect of T-2 toxin on apoptosis of fetus chondrocytes

    Institute of Scientific and Technical Information of China (English)

    杨天府; 贾志强; 沈彬

    2001-01-01

    目的 探讨T-2毒素与软骨细 胞凋亡的关系。方法 水囊引产胎儿的软骨细胞体外单层培养。T-2 毒素浓度分为0,5,10,20和40 μg/L 5组,第1代软骨细胞接种后培养4 d,加入不同浓 度的T-2毒素,作用16 h。应用TUNEL法和流式细胞技术定性和定量检测软骨细胞凋 亡。同时观察T-2毒素对软骨细胞增殖的影响。结果 各组细胞在加入T-2毒素后,胞体明显皱缩,T-2 毒素浓度越大,皱缩越严重。流式细胞仪检测与TdT中介脱氧尿苷三磷酸末端标记(TU NEL)法检测均发现,当T-2毒素在0~10 μg/L之间时,T-2毒素浓度越大,凋亡细胞越多。结论 T-2毒素对软骨细胞的增殖有明显的抑制作用,并与T-2毒素浓度呈剂量—效应关系。T-2毒素可以引起体外培养的软骨细胞凋亡,且与T-2 毒素浓度有一定关系。%Objective To investigate the effect of T-2 toxin on apoptosis of chondrocytes.Methods Chondrocytes which were obtained from aborted fetal were cultured in vitro.Four days later,these chondrocytes were exposed to T-2 toxin in different concetrations for 16 hours.According to the concentratio ns,five experimental groups were divided:0,5,10,20,40 μg/L.Then TUNEL staining and Flowcytometry were used to detect the apoptosis of chondrocytes qualitativel y and quantitatively,the effect of T-2 toxin on proliferation of chondrocytes were also observed.Results After being exposed to T-2 toxin,the body of chondrocytes shrinked obviously and there was a dose-dependent relationship bet ween the toxin concentration and the degree of shrink.The concentration of T-2 toxin changed from 0 μg/L to 10 ng/ml,the number of apoptosis increased.Conclusions  T-2 toxin can inhibit the proliferation of chondroyte significantly in a dose-depenent manner. T-2 toxin can induce the apoptosis of chondrocyte and the numbers of apoptosis is proportionate to the concentration of T-2 toxin in particular

  18. Reversed field pinch operation with intelligent shell feedback control in EXTRAP T2R

    Science.gov (United States)

    Brunsell, P. R.; Kuldkepp, M.; Menmuir, S.; Cecconello, M.; Hedqvist, A.; Yadikin, D.; Drake, J. R.; Rachlew, E.

    2006-11-01

    Discharges in the thin shell reversed field pinch (RFP) device EXTRAP T2R without active feedback control are characterized by growth of non-resonant m = 1 unstable resistive wall modes (RWMs) in agreement with linear MHD theory. Resonant m = 1 tearing modes (TMs) exhibit initially fast rotation and the associated perturbed radial fields at the shell are small, but eventually TMs wall-lock and give rise to a growing radial field. The increase in the radial field at the wall due to growing RWMs and wall-locked TMs is correlated with an increase in the toroidal loop voltage, which leads to discharge termination after 3-4 wall times. An active magnetic feedback control system has been installed in EXTRAP T2R. A two-dimensional array of 128 active saddle coils (pair-connected into 64 independent m = 1 coils) is used with intelligent shell feedback control to suppress the m = 1 radial field at the shell. With feedback control, active stabilization of the full toroidal spectrum of 16 unstable m = 1 non-resonant RWMs is achieved, and TM wall locking is avoided. A three-fold extension of the pulse length, up to the power supply limit, is observed. Intelligent shell feedback control is able to maintain the plasma equilibrium for 10 wall times, with plasma confinement parameters sustained at values comparable to those obtained in thick shell devices of similar size.

  19. Measurement of the muon beam direction and muon flux for the T2K neutrino experiment

    CERN Document Server

    Suzuki, K; Ariga, A; Ariga, T; Bay, F; Bronner, C; Ereditato, A; Friend, M; Hartz, M; Hiraki, T; Ichikawa, A K; Ishida, T; Ishii, T; Juget, F; Kikawa, T; Kobayashi, T; Kubo, H; Matsuoka, K; Maruyama, T; Minamino, A; Murakami, A; Nakadaira, T; Nakaya, T; Nakayoshi, K; Oyama, Y; Pistillo, C; Sakashita, K; Sekiguchi, T; Suzuki, S Y; Tada, S; Yamada, Y; Yamamoto, K; Yokoyama, M

    2014-01-01

    The Tokai-to-Kamioka (T2K) neutrino experiment measures neutrino oscillations by using an almost pure muon neutrino beam produced at the J-PARC accelerator facility. The T2K muon monitor was installed to measure the direction and stability of the muon beam which is produced together with the muon neutrino beam. The systematic error in the muon beam direction measurement was estimated, using data and MC simulation, to be 0.28 mrad. During beam operation, the proton beam has been controlled using measurements from the muon monitor and the direction of the neutrino beam has been tuned to within 0.3 mrad with respect to the designed beam-axis. In order to understand the muon beam properties,measurement of the absolute muon yield at the muon monitor was conducted with an emulsion detector. The number of muon tracks was measured to be $(4.06\\pm0.05)\\times10^4$ cm$^{-2}$ normalized with $4\\times10^{11}$ protons on target with 250 kA horn operation. The result is in agreement with the prediction which is corrected ba...

  20. Oncologic Results of Retroperitoneoscopic Versus Open Surgery for T2 Upper Tract Urothelial Carcinoma.

    Science.gov (United States)

    Shan, Hongli; Wang, Xiaoqing; Sun, Qingnian; Chen, Qihui; Xu, Bo; Hao, Yuanyuan; Xu, Wei

    2015-12-01

    The present study was designed to compare oncologic outcomes of T2 upper tract urothelial carcinoma patients treated with retroperitoneoscopic nephroureterectomy (RNU) or open radical nephroureterectomy (ONU). T2 upper tract urothelial carcinoma patients were treated with RNU (n = 110) or ONU (n = 118) and followed-up for > 5 years. Demographic and clinical data, including preoperative indexes, intraoperative indexes, and oncological outcomes, were retrospectively compared to determine the efficacy of the 2 procedures. The RNU and ONU groups were statistically similar in age, sex, tumor location, and tumor pathologic grade. The original surgery time required for RNU and ONU was statistically similar, but RNU was associated with a significantly smaller volume of intraoperative estimated blood loss and shorter length of postoperative hospital stay. Follow-up (average: 43.2 months; range, 6-72 months) revealed that the estimated 5-year overall survival rate and the estimated 5-year disease-specific survival rate after RNU was slightly worse than after ONU (66.0% vs. 67.1%, and 80.8% vs. 83.8%, respectively), and the estimated 5-year recurrence-free survival rate and the estimated 5-year intravesical recurrence-free survival rates were slightly better than ONU (79.5% vs. 77.9%, and 68.3% vs. 65.6%, respectively). However, none of these differences were statistically significant. The open surgery strategy and the RNU strategy are equally effective for treating T2 upper tract urothelial carcinoma. However, the RNU procedure is safer, less invasive, and requires a shorter duration of postoperative hospitalized care; thus, RNU is recommended as the preferred strategy. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Physiological noise in murine solid tumours using T2*-weighted gradient-echo imaging: a marker of tumour acute hypoxia?

    Science.gov (United States)

    Baudelet, Christine; Ansiaux, Réginald; Jordan, Bénédicte F.; Havaux, Xavier; Macq, Benoit; Gallez, Bernard

    2004-08-01

    T2*-weighted gradient-echo magnetic resonance imaging (T2*-weighted GRE MRI) was used to investigate spontaneous fluctuations in tumour vasculature non-invasively. FSa fibrosarcomas, implanted intramuscularly (i.m.) in the legs of mice, were imaged at 4.7 T, over a 30 min or 1 h sampling period. On a voxel-by-voxel basis, time courses of signal intensity were analysed using a power spectrum density (PSD) analysis to isolate voxels for which signal changes did not originate from Gaussian white noise or linear drift. Under baseline conditions, the tumours exhibited spontaneous signal fluctuations showing spatial and temporal heterogeneity over the tumour. Statistically significant fluctuations occurred at frequencies ranging from 1 cycle/3 min to 1 cycle/h. The fluctuations were independent of the scanner instabilities. Two categories of signal fluctuations were reported: (i) true fluctuations (TFV), i.e., sequential signal increase and decrease, and (ii) profound drop in signal intensity with no apparent signal recovery (SDV). No temporal correlation between tumour and contralateral muscle fluctuations was observed. Furthermore, treatments aimed at decreasing perfusion-limited hypoxia, such as carbogen combined with nicotinamide and flunarizine, decreased the incidence of tumour T2*-weighted GRE fluctuations. We also tracked dynamic changes in T2* using multiple GRE imaging. Fluctuations of T2* were observed; however, fluctuation maps using PSD analysis could not be generated reliably. An echo-time dependency of the signal fluctuations was observed, which is typical to physiological noise. Finally, at the end of T2*-weighted GRE MRI acquisition, a dynamic contrast-enhanced MRI was performed to characterize the microenvironment in which tumour signal fluctuations occurred in terms of vessel functionality, vascularity and microvascular permeability. Our data showed that TFV were predominantly located in regions with functional vessels, whereas SDV occurred in regions

  2. Dephasing in an atom

    OpenAIRE

    2011-01-01

    When an atom in vacuum is near a surface of a dielectric the energy of a fluctuating electromagnetic field depends on a distance between them resulting, as known, in the force called van der Waals one. Besides this fluctuation phenomenon there is one associated with formation of a mean electric field which is equivalent to an order parameter. In this case atomic electrons are localized within atomic distances close to the atom and the total ground state energy is larger, compared to the bare ...

  3. T2 and T2* measurements of fetal brain oxygenation during hypoxia with MRI at 3T: correlation with fetal arterial blood oxygen saturation

    Energy Technology Data Exchange (ETDEWEB)

    Wedegaertner, Ulrike; Adam, Gerhard [Universitaetsklinikum Hamburg-Eppendorf, Department of Diagnostic and Interventional Radiology, Hamburg (Germany); Kooijman, Hendrik [Philips Medical Systems, Best (Netherlands); Andreas, Thomas; Beindorff, Nicola; Hecher, Kurt [University Hospital Hamburg-Eppendorf, Department of Obstetrics and Prenatal Medicine, Hamburg (Germany)

    2010-01-15

    The purpose of this prospective study was to determine the oxygen saturation of blood in the fetal brain based on T2 and T2* measurements in a fetal sheep model. Five sheep fetuses were investigated during normoxia and hypoxia by 3T MRI. Multi-echo gradient-echo and turbo-spin-echo sequences were performed on the fetal brain. MR-determined oxygen saturation (MR-sO{sub 2}) of blood in the fetal brain was calculated based on T2 and T2* values. Fetal arterial blood oxygen saturation (blood-sO{sub 2}) was measured during the two experimental phases. The slope of MR-sO{sub 2} as a function of blood-sO{sub 2} was estimated and tested for compatibility using the one-sample t-test. During normoxia, mean values for carotid blood oxygen saturation were 67%, 83 ms for T2*, 202 ms for T2 and 96% for MR-sO{sub 2}. During hypoxia, arterial blood oxygen saturation, T2* and calculated MR-sO{sub 2} decreased to 22%, 64 ms, and 68% respectively. The one-sample t-test revealed the slope to be significantly different from 0(T=5.023, df=4, P=0.007). It is feasible to perform quantitative T2 and T2* measurements in the fetal brain. MR-sO{sub 2} and fetal arterial blood oxygen saturation correlated significantly. However, based on these data a reliable quantification of fetal brain tissue oxygenation is not possible. (orig.)

  4. Radiated Power and Impurity Concentrations in the EXTRAP-T2R Reversed-Field Pinch

    Science.gov (United States)

    Corre, Y.; Rachlew, E.; Cecconello, M.; Gravestijn, R. M.; Hedqvist, A.; Pégourié, B.; Schunke, B.; Stancalie, V.

    2005-01-01

    A numerical and experimental study of the impurity concentration and radiation in the EXTRAP-T2R device is reported. The experimental setup consists of an 8-chord bolometer system providing the plasma radiated power and a vacuum-ultraviolet spectrometer providing information on the plasma impurity content. The plasma emissivity profile as measured by the bolometric system is peaked in the plasma centre. A one dimensional Onion Skin Collisional-Radiative model (OSCR) has been developed to compute the density and radiation distributions of the main impurities. The observed centrally peaked emissivity profile can be reproduced by OSCR simulations only if finite particle confinement time and charge-exchange processes between plasma impurities and neutral hydrogen are taken into account. The neutral hydrogen density profile is computed with a recycling code. Simulations show that recycling on metal first wall such as in EXTRAP-T2R (stainless steel vacuum vessel and molybdenum limiters) is compatible with a rather high neutral hydrogen density in the plasma centre. Assuming an impurity concentration of 10% for oxygen and 3% for carbon compared with the electron density, the OSCR calculation including lines and continuum emission reproduces about 60% of the total radiated power with a similarly centrally peaked emissivity profile. The centrally peaked emissivity profile is due to low ionisation stages and strongly radiating species in the plasma core, mainly O4+ (Be-like) and C3+ Li-like.

  5. Measurement of neutrino interactions in gaseous argon with T2K

    CERN Document Server

    ,

    2016-01-01

    The T2K near-detector, ND280, employs three large argon gas TPCs (Time Projection Chambers) for particle tracking and identification. The gas inside the TPCs can be used as an active target to study the neutrino interactions in great detail. The low density of the gas leads to very low track energy thresholds, allowing the reconstruction of very low momentum tracks, e.g. protons with kinetic energies down to $\\mathcal{O}$(1 MeV). Since different nuclear interaction models vary considerably in their predictions of those low momentum track multiplicities, this makes neutrino interactions on gases a powerful probe to test those models. The TPCs operate with an argon-based gas mixture (95% by volume) and have been exposed to the T2K neutrino beam since the beginning of the experiment in 2010. Due to the low total mass of the gas, neutrino argon interactions happen only rarely, compared to the surrounding scintillator-based detectors. We expect about 600 such events in the recorded data so far (about 200 in the fi...

  6. Two-dimensional T2 distribution mapping in rock core plugs with optimal k-space sampling.

    Science.gov (United States)

    Xiao, Dan; Balcom, Bruce J

    2012-07-01

    Spin-echo single point imaging has been employed for 1D T(2) distribution mapping, but a simple extension to 2D is challenging since the time increase is n fold, where n is the number of pixels in the second dimension. Nevertheless 2D T(2) mapping in fluid saturated rock core plugs is highly desirable because the bedding plane structure in rocks often results in different pore properties within the sample. The acquisition time can be improved by undersampling k-space. The cylindrical shape of rock core plugs yields well defined intensity distributions in k-space that may be efficiently determined by new k-space sampling patterns that are developed in this work. These patterns acquire 22.2% and 11.7% of the k-space data points. Companion density images may be employed, in a keyhole imaging sense, to improve image quality. T(2) weighted images are fit to extract T(2) distributions, pixel by pixel, employing an inverse Laplace transform. Images reconstructed with compressed sensing, with similar acceleration factors, are also presented. The results show that restricted k-space sampling, in this application, provides high quality results.

  7. T2 mapping provides multiple approaches to characterize muscle involvement in neuromuscular diseases: a cross-sectional study of lower leg muscles in 5–15 year old boys with Duchenne Muscular Dystrophy

    Science.gov (United States)

    Arpan, Ishu; Forbes, Sean C; Lott, Donovan J; Senesac, Claudia R; Daniels, Michael J; Triplett, William T; Deol, Jasjit K; Sweeney, H Lee; Walter, Glenn A; Vandenborne, Krista

    2012-01-01

    Purpose Skeletal muscles of children with Duchenne muscular dystrophy (DMD) have enhanced susceptibility to damage and progressive lipid infiltration, which contribute to an increase in magnetic resonance proton transverse relaxation time (T2). Therefore, examining T2 changes in individual muscles may be useful for monitoring disease progression in DMD. In this study we utilized mean T2, percent elevated pixels, and T2 heterogeneity to assess changes in composition of dystrophic muscles. In addition, we used fat saturation (fatsat) to distinguish T2 changes due to edema and inflammation from fat infiltration in muscles. Methods Thirty subjects with DMD and 15 age-matched controls underwent T2-weighted imaging of their lower leg using 3-T MR system. T2 maps were developed and four lower leg muscles were manually traced (soleus, medial gastrocnemius, peroneal and tibialis anterior). Mean T2 of the traced regions of interest (ROI), width of T2 histograms, and percent-elevated pixels were calculated. Results We found that even in young children with DMD, muscles had elevated mean T2, were more heterogeneous, and had a greater percent-elevated pixels in the lower leg muscles than controls. T2 measures decreased with fat saturation, but were still higher (pmuscles than controls. Further, T2 measures showed positive correlations with timed functional tests (r=0.23–0.79). Conclusion The elevated T2 measures with and without fat saturation in all ages of DMD examined (5–15 years) compared to unaffected controls indicate that the dystrophic muscles have increased regions of damage, edema, and fat infiltration. This study shows that T2 mapping provides multiple approaches that can be effectively utilized to characterize muscle tissue in children with DMD even in the early stages of the disease. Therefore, T2 mapping may prove clinically useful in monitoring muscle changes due to disease process or therapeutic interventions in DMD. PMID:23044995

  8. Axial T2* mapping in intervertebral discs: a new technique for assessment of intervertebral disc degeneration

    Energy Technology Data Exchange (ETDEWEB)

    Hoppe, Sven; Quirbach, Sebastian; Krause, Fabian G.; Benneker, Lorin M. [Inselspital, Berne University Hospital, Department of Orthopaedic Surgery, Berne (Switzerland); Mamisch, Tallal C. [Inselspital, Berne University Hospital, Department of Radiology, Berne (Switzerland); Werlen, Stefan [Clinic Sonnenhof, Department of Radiology, Berne (Switzerland)

    2012-09-15

    To demonstrate the potential benefits of biochemical axial T2* mapping of intervertebral discs (IVDs) regarding the detection and grading of early stages of degenerative disc disease using 1.5-Tesla magnetic resonance imaging (MRI) in a clinical setting. Ninety-three patients suffering from lumbar spine problems were examined using standard MRI protocols including an axial T2* mapping protocol. All discs were classified morphologically and grouped as ''healthy'' or ''abnormal''. Differences between groups were analysed regarding to the specific T2* pattern at different regions of interest (ROIs). Healthy intervertebral discs revealed a distinct cross-sectional T2* value profile: T2* values were significantly lower in the annulus fibrosus compared with the nucleus pulposus (P = 0.01). In abnormal IVDs, T2* values were significantly lower, especially towards the centre of the disc representing the expected decreased water content of the nucleus (P = 0.01). In herniated discs, ROIs within the nucleus pulposus and ROIs covering the annulus fibrosus showed decreased T2* values. Axial T2* mapping is effective to detect early stages of degenerative disc disease. There is a potential benefit of axial T2* mapping as a diagnostic tool, allowing the quantitative assessment of intervertebral disc degeneration. circle Axial T2* mapping effective in detecting early degenerative disc disease. (orig.)

  9. High-Quality T2-Weighted 4-Dimensional Magnetic Resonance Imaging for Radiation Therapy Applications

    Energy Technology Data Exchange (ETDEWEB)

    Du, Dongsu [Department of Radiation Oncology, Washington University School of Medicine, Saint Louis, Missouri (United States); Caruthers, Shelton D. [Philips Healthcare, Cleveland, Ohio (United States); Glide-Hurst, Carri [Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan (United States); Low, Daniel A. [Department of Radiation Oncology, University of California-Los Angeles, Los Angeles, California (United States); Li, H. Harold; Mutic, Sasa [Department of Radiation Oncology, Washington University School of Medicine, Saint Louis, Missouri (United States); Hu, Yanle, E-mail: Hu.Yanle@mayo.edu [Department of Radiation Oncology, Washington University School of Medicine, Saint Louis, Missouri (United States); Department of Radiation Oncology, Mayo Clinic in Arizona, Phoenix, Arizona (United States)

    2015-06-01

    Purpose: The purpose of this study was to improve triggering efficiency of the prospective respiratory amplitude-triggered 4-dimensional magnetic resonance imaging (4DMRI) method and to develop a 4DMRI imaging protocol that could offer T2 weighting for better tumor visualization, good spatial coverage and spatial resolution, and respiratory motion sampling within a reasonable amount of time for radiation therapy applications. Methods and Materials: The respiratory state splitting (RSS) and multi-shot acquisition (MSA) methods were analytically compared and validated in a simulation study by using the respiratory signals from 10 healthy human subjects. The RSS method was more effective in improving triggering efficiency. It was implemented in prospective respiratory amplitude-triggered 4DMRI. 4DMRI image datasets were acquired from 5 healthy human subjects. Liver motion was estimated using the acquired 4DMRI image datasets. Results: The simulation study showed the RSS method was more effective for improving triggering efficiency than the MSA method. The average reductions in 4DMRI acquisition times were 36% and 10% for the RSS and MSA methods, respectively. The human subject study showed that T2-weighted 4DMRI with 10 respiratory states, 60 slices at a spatial resolution of 1.5 × 1.5 × 3.0 mm{sup 3} could be acquired in 9 to 18 minutes, depending on the individual's breath pattern. Based on the acquired 4DMRI image datasets, the ranges of peak-to-peak liver displacements among 5 human subjects were 9.0 to 12.9 mm, 2.5 to 3.9 mm, and 0.5 to 2.3 mm in superior-inferior, anterior-posterior, and left-right directions, respectively. Conclusions: We demonstrated that with the RSS method, it was feasible to acquire high-quality T2-weighted 4DMRI within a reasonable amount of time for radiation therapy applications.

  10. Dual-pathway multi-echo sequence for simultaneous frequency and T2 mapping

    Science.gov (United States)

    Cheng, Cheng-Chieh; Mei, Chang-Sheng; Duryea, Jeffrey; Chung, Hsiao-Wen; Chao, Tzu-Cheng; Panych, Lawrence P.; Madore, Bruno

    2016-04-01

    Purpose: To present a dual-pathway multi-echo steady state sequence and reconstruction algorithm to capture T2, T2∗ and field map information. Methods: Typically, pulse sequences based on spin echoes are needed for T2 mapping while gradient echoes are needed for field mapping, making it difficult to jointly acquire both types of information. A dual-pathway multi-echo pulse sequence is employed here to generate T2 and field maps from the same acquired data. The approach might be used, for example, to obtain both thermometry and tissue damage information during thermal therapies, or susceptibility and T2 information from a same head scan, or to generate bonus T2 maps during a knee scan. Results: Quantitative T2, T2∗ and field maps were generated in gel phantoms, ex vivo bovine muscle, and twelve volunteers. T2 results were validated against a spin-echo reference standard: A linear regression based on ROI analysis in phantoms provided close agreement (slope/R2 = 0.99/0.998). A pixel-wise in vivo Bland-Altman analysis of R2 = 1/T2 showed a bias of 0.034 Hz (about 0.3%), as averaged over four volunteers. Ex vivo results, with and without motion, suggested that tissue damage detection based on T2 rather than temperature-dose measurements might prove more robust to motion. Conclusion: T2, T2∗ and field maps were obtained simultaneously, from the same datasets, in thermometry, susceptibility-weighted imaging and knee-imaging contexts.

  11. One loop amplitude for Heterotic string on $T^2$

    CERN Document Server

    Sasmal, Soumya

    2016-01-01

    We revisit the results of one loop string amplitude calculations for the Heterotic string theory compactified on a torus with or without Wilson lines. We give the complete elliptic genus and the harmonic part of the CP-even amplitude for the gauge groups $SO(32)$, $E_8 \\times E_8$, $SO(16)^2$ and $SO(8)^4$.

  12. Note on four-particle form factors of operators $T_{2n}T_{-2n}$ in sinh-Gordon model

    CERN Document Server

    Lashkevich, Michael

    2016-01-01

    The diagonal matrix elements $\\langle\\theta_1,\\theta_2|T_{2n}T_{-2n}|\\theta_1,\\theta_2\\rangle$ between two-particle states in the sinh-Gordon model are computed analytically for all integers $n>0$. This confirms the proposal by F. Smirnov and A. Zamolodchikov for these matrix elements and demonstrates effectiveness of the algebraic approach to form factors.

  13. Long-term results of a randomized controlled trial of T2 versus T2-T3 ablation in endoscopic thoracic sympathectomy for palmar hyperhidrosis.

    Science.gov (United States)

    Ong, Wilson; Lee, Alvin; Tan, Wee Boon; Lomanto, Davide

    2016-03-01

    Despite good short-term results and patient satisfaction with endoscopic thoracic sympathectomy (ETS), there has been much debate on the level of sympathectomy for treatment of palmar hyperhidrosis (PH) in terms of long-term clinical outcomes. The aim of the study was to analyze the long-term recurrence and compensatory hyperhidrosis (CH) rates of ETS, comparing single-level T2 against multi-level T2-T3 ablation in single patients. Patients who had undergone treatment for PH with unilateral T2 and contralateral T2-T3 ablation in ETS were retrospectively reviewed. They were subjected to telephone interview using standardized set of interview script and questionnaire with a scoring system similar to hyperhidrosis disease severity scale. All patients were evaluated for comparison of symptom resolution, site and severity of CH, and satisfaction rates. To compare between T2 and T2-T3, the level of sympathectomy on one side is matched to the ipsilateral recurrence of PH and CH occurrence. Twenty-two patients with a mean age of 36.5 years could be reached. The mean follow-up was 8 years (range 38-153 months). The global recurrence rate for PH is 18%. CH was observed in 20 (91%) patients, and trunk compensation was the most common (18/22-82%), followed by lower limb (14/22-64%) and axilla (10/22-45%). Overall, 72.8% (16) of the patients were satisfied with the operation. Among the six patients who were not satisfied, two patients reported recurrence of symptoms, while four patients experienced some form of compensation. There was no absolute difference in the severity of sweating bilaterally for patients who reported recurrence of PH. The site and severity of CH were also bilaterally symmetrical for all patients. There was no difference in recurrence rates and CH between single-level (T2) and multi-level (T2-T3) ETSs in the long term.

  14. Cortical T2 signal shortening in amyotrophic lateral sclerosis is not due to iron deposits

    Energy Technology Data Exchange (ETDEWEB)

    Hecht, M.J.; Neundoerfer, B. [University of Erlangen-Nurenberg, Department of Neurology, Erlangen (Germany); Fellner, C.; Fellner, F.A. [University of Erlangen-Nurenberg, Institute of Diagnostic Radiology, Erlangen (Germany); Landes-Nervenklinik Wagner-Jauregg, Institute of Radiology, Linz (Austria); Schmid, A. [University of Erlangen-Nurenberg, Institute of Diagnostic Radiology, Erlangen (Germany)

    2005-11-01

    Signal shortening of the motor cortex in T2-weighted MR images is a frequent finding in patients with amyotrophic lateral sclerosis (ALS). The cause of signal shortening in ALS is unknown, although iron deposits have been suggested. To test this hypothesis, we acquired T2*-weighted gradient-echo (GRE) MR images in addition to T2-weighted turbo spin-echo in 69 patients with ALS. Signal shortening in T2-weighted images was found in 31 patients. In T2*-weighted GRE images, only three patients had signal shortening. One patient with additional bifrontal haemorrhage had frontal but no motor cortex signal shortening. Iron deposits do not cause cortical signal shortening in patients with ALS predominantly. Other factors are presumably more important in the generation of cortical T2 shortening in ALS. (orig.)

  15. Adiponectin may improve osseointegration of dental implants in T2DM patients.

    Science.gov (United States)

    Bai, Yun; Yin, Guozhu; Luo, En

    2011-08-01

    Type 2 diabetes mellitus (T2DM) is the most common form of diabetes. Compared with the general population, a higher failure rate is seen in T2DM patients. There is also evidence that chronically high levels of plasma glycemia leads to inflammatory effect and a negative influence on bone formation and remodeling, and reduce osseointegration of implants. Recently studies reveal that adiponectin is an insulin-sensitizing adipokine, and closely associated with T2DM. Adiponectin has potent anti-inflammatory properties and has been shown to increase bone density by inhibiting osteoclast formation and promoting the formation of osteoblasts. We therefore hypothesize systemically infused or locally used adiponectin could accelerate osseointegration of dental implants in T2DM. Our hypothesis could help to create an option to improve success ratio of dental implants in T2DM by the replenishment of adiponectin in T2DM patients.

  16. Diffuse Cerebral White Matter T2-Weighted Hyperintensity: A New Finding of General Paresis

    Energy Technology Data Exchange (ETDEWEB)

    Alam, F.; Yasutomi, H.; Fukuda, H.; Horiguchi, J.; Murakami, Y.; Ohshita, T.; Inoue, K.; Ito, K. [Graduate School of Biomedical Sciences, Hiroshima Univ. (Japan). Depts. of Radiology, and Clinical Neurosciences and Therapeutics

    2006-07-15

    General paresis (parenchymatous neurosyphilis) is a rare disease, and in recent years the number of papers published on the magnetic resonance imaging findings has been limited. The findings are as follows: cerebral atrophy; mesiotemporal T2 hyperintensity; ventriculomegaly; pathological T2 hypointensity of the globus pallidus, putamen, the head of the caudate nucleus and thalamus. We present a new finding, diffuse cerebral white matter T2 hyperintensity, observed in a patient with general paresis with a 5-year history of progressive dementia.

  17. The development of form two mathematics i-Think module (Mi-T2)

    Science.gov (United States)

    Yao, Foo Jing; Abdullah, Mohd Faizal Nizam Lee; Tien, Lee Tien

    2017-05-01

    This study aims to develop a training module i-THINK Mathematics Form Two (Mi-T2) to increase the higher-order thinking skills of students. The Mi-T2 training module was built based on the Sidek Module Development Model (2001). Constructivist learning theory, cognitive learning theory, i-THINK map and higher order thinking skills were the building blocks of the module development. In this study, researcher determined the validity and reliability of Mi-T2 module. The design being used in this study was descriptive study. To determine the needs of Mi-T2 module, questionnaires and literature review were used to collect data. When the need of the module was determined, the module was built and a pilot study was conducted to test the reliability of the Mi-T2 module. The pilot study was conducted at a secondary school in North Kinta, Perak. A Form Two class was selected to be the sample study through clustered random sampling. The pilot study was conducted for two months and one topic had been studied. The Mi-T2 module was evaluated by five expert panels to determine the content validity of the module. The instruments being used in the study were questionnaires about the necessity of the Mi-T2 module for guidance, questionnaires about the validity of the module and questionnaires concerning the reliability of the module. Statistical analysis was conducted to determine the validity and reliability coefficients of the Mi-T2 module. The content validity of Mi-T2 module was determined by Cohen's Kappa's (1968) agreement coefficient and the reliability of Mi-T2 module was determined by Cronbach Alpha's value scale. The content validity of Mi-T2 module was 0.89 and the Cronbach Alpha's value of Mi-T2 module was 0.911.

  18. Survey of T-2 and HT-2 toxins by LC-MS/MS in oats and oat products from European oat mills in 2005-2009.

    Science.gov (United States)

    Pettersson, Hans; Brown, Colin; Hauk, Julia; Hoth, Stefan; Meyer, Jens; Wessels, Detlev

    2011-01-01

    T-2 and HT-2 toxins were analysed in oats (n = 243), oat flakes (n = 529), oat meal (n = 105) and oat by-products (n = 209) from 11 European mills during 2005-2009 by high-performance liquid chromatography with a triple quadrupole mass spectrometer. Limits of quantification were 5 µg kg(-1) for both T-2 and HT-2 toxins in oats. The incidence of T-2 + HT-2 (>5 µg kg(-1)) in oats, oat flakes, oat meal and oat by-products was 93, 77, 34 and 99%, respectively. The mean values of T-2 + HT-2 were 94, 17, 11 and 293 µg kg(-1) for oats, oat flakes, oat meal and oat by-products, respectively. T-2 and HT-2 occurred together and the T-2 level was 52% of HT-2 in oats. Maximal T-2 and HT-2 concentration in oat flakes and oat meal were 197 and 118 µg kg(-1). The toxins were reduced by 82-88% during processing, but increased 3.1 times in oat by-products.

  19. Electron in the field of flexural vibrations of a membrane: Quantum time, magnetic oscillations, and coherence breaking

    Science.gov (United States)

    Gornyi, I. V.; Dmitriev, A. P.; Mirlin, A. D.; Protopopov, I. V.

    2016-08-01

    We have studied the motion of an electron in a membrane under the influence of flexural vibrations with a correlator that decreases upon an increase in the distance in accordance with the law r-2η. We have conducted a detailed consideration of the case with η < 1/2, in which the perturbation theory is inapplicable, even for an arbitrarily weak interaction. It is shown that, in this case, reciprocal quantum time 1/τ q is proportional to g 1/(1-η) T (2-η)/(2-2η), where g is the electron-phonon interaction constant and T is the temperature. The method developed here is applied for calculating the electron density of states in a magnetic field perpendicular to the membrane. In particular, it is shown that the Landau levels in the regime with ω c τ q » 1 have a Gaussian shape with a width that depends on the magnetic field as B η. In addition, we calculate the time τφ of dephasing of the electron wave function that emerges due to the interaction with flexural phonons for η < 1/2. It has been shown that, in several temperature intervals, quantity 1/τφ can be expressed by various power functions of the electron-phonon interaction constant, temperature, and electron energy.

  20. Should T2K run in dominant neutrino mode to detect CP violation ?

    CERN Document Server

    Ghosh, Monojit

    2016-01-01

    The main aim of the T2K experiment in Japan is to discover CP violation in the leptonic sector by measuring the Dirac phase $\\delta_{CP}$. For that purpose T2K has already started collecting data in both neutrino and antineutrino mode. But in this work we will show that, in T2K the main role of the antineutrinos is to resolve the octant degeneracy. If the octant is known then the pure neutrino run of T2K is capable to give the maximum CP sensitivity. On the other hand in the experiment like NO$\

  1. T2-weighted imaging of the heart—A pictorial review

    Energy Technology Data Exchange (ETDEWEB)

    Mirakhur, Anirudh, E-mail: ani.mirakhur@gmail.com [Department of Diagnostic Imaging, Foothills Medical Centre, University of Calgary, Calgary (Canada); Anca, Nicoleta, E-mail: nicoletanca@gmail.com [Department of Diagnostic Imaging, Foothills Medical Centre, University of Calgary, Calgary (Canada); Mikami, Yoko, E-mail: yokomikami@gmail.com [Stephenson Cardiovascular MR Centre, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary (Canada); Merchant, Naeem, E-mail: n.merchant22@gmail.com [Department of Diagnostic Imaging, Foothills Medical Centre, University of Calgary, Calgary (Canada); Stephenson Cardiovascular MR Centre, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary (Canada)

    2013-10-01

    Spin-Echo techniques in cardiovascular magnetic resonance (CMR) have been used for decades, primarily to image cardiac anatomy. More recently, T2-weighted (T2W) imaging has seen an increased role in CMR protocols, especially in tissue characterization in acute myocardial processes. This article will review current methodologies of cardiac T2W acquisition and their limitations, as well as approach to both semi-quantitative and quantitative analyses. The appearance and utility of T2W imaging in a myriad of pathologic myocardial processes such as acute myocardial infarction, acute viral myocarditis, reversible stress-related cardiomyopathy, hypertrophic cardiomyopathy, and cardiac sarcoidosis, will also be discussed.

  2. Proton MR spectroscopic imaging of basal ganglia and thalamus in neurofibromatosis type 1: correlation with T2 hyperintensities

    Energy Technology Data Exchange (ETDEWEB)

    Barbier, Charlotte; Barantin, Laurent [CHRU and Tours University, Department of Neuroradiology, Tours (France); Chabernaud, Camille [CHRU and Tours University et INSERM U930, Department of Pediatric Neurology, Tours (France); Bertrand, Philippe [CHRU and Tours University, Department of Radiology, Tours (France); Sembely, Catherine; Sirinelli, Dominique [CHRU and Tours University, Department of Pediatric Radiology, Tours (France); Castelnau, Pierre [CHRU and Tours University et INSERM U930, Department of Pediatric Neurology, Tours (France); CHRU and Tours University et INSERM U930, Tours (France); Neurologie Pediatrique and INSERM U930, Hopital d' Enfants Gatien de Clocheville, Tours cedex 09 (France); Cottier, Jean-Philippe [CHRU and Tours University, Department of Neuroradiology, Tours (France); CHRU and Tours University et INSERM U930, Tours (France)

    2011-02-15

    Neurofibromatosis type 1 (NF1) is frequently associated with hyperintense lesions on T2-weighted images called ''unidentified bright objects'' (UBO). To better characterize the functional significance of UBO, we investigate the basal ganglia and thalamus using spectroscopic imaging in children with NF1 and compare the results to anomalies observed on T2-weighted images. Magnetic resonance (MR) data of 25 children with NF1 were analyzed. On the basis of T2-weighted images analysis, two groups were identified: one with normal MR imaging (UBO- group; n = 10) and one with UBO (UBO+ group; n = 15). Within the UBO+ group, a subpopulation of patients (n = 5) only had lesions of the basal ganglia. We analyzed herein seven regions of interest (ROIs) for each side: caudate nucleus, capsulo-lenticular region, lateral and posterior thalamus, thalamus (lateral and posterior voxels combined), putamen, and striatum. For each ROI, a spectrum of the metabolites and their ratio was obtained. Patients with abnormalities on T2-weighted images had significantly lower NAA/Cr, NAA/Cho, and NAA/mI ratios in the lateral right thalamus compared with patients with normal T2. These abnormal spectroscopic findings were not observed in capsulo-lenticular regions that had UBO but in the thalamus region that was devoid of UBO. Multivoxel spectroscopic imaging using short-time echo showed spectroscopic abnormalities in the right thalamus of NF1 patients harboring UBO, which were mainly located in the basal ganglia. This finding could reflect the anatomical and functional interactions of these regions. (orig.)

  3. The roles of carboxylesterase and CYP isozymes on the in vitro metabolism of T-2 toxin

    Institute of Scientific and Technical Information of China (English)

    Ni-ni Lin; Jia Chen; Bin Xu; Xia Wei; Lei Guo; Jian-wei Xie

    2015-01-01

    Background: T-2 toxin poses a great threat to human health because it has the highest toxicity of the currently known trichothecene mycotoxins. To understand thein vivo toxicity and transformation mechanism of T-2 toxin, we investigated the role of two principal phaseⅠ drug-metabolizing enzymes (cytochrome P450 [CYP450] enzymes) on the metabolism of T-2 toxin, which are crucial to the metabolism of endogenous substances and xenobiotics. We also investigated carboxylesterase, which also plays an important role in the metabolism of toxic substances. Methods: A chemical inhibition method and a recombinant method were employed to investigate the metabolism of the T-2 toxin by the CYP450 enzymes, and a chemical inhibition method was used to study carboxylesterase metabolism. Samples incubated with human liver microsomes were analyzed by high performance liquid chromatography-triple quadrupole mass spectrometry (HPLC- QqQ MS) after a simple pretreatment. Results: In the presence of a carboxylesterase inhibitor, only 20% T-2 toxin was metabolized. When CYP enzyme inhibitors and a carboxylesterase inhibitor were both present, only 3% of the T-2 toxin was metabolized. The contributions of the CYP450 enzyme family to T-2 toxin metabolism followed the descending order CYP3A4, CYP2E1, CYP1A2, CYP2B6 or CYP2D6 or CYP2C19. Conclusions: Carboxylesterase and CYP450 enzymes are of great importance in T-2 toxin metabolism, in which carboxylesterase is predominant and CYP450 has a subordinate role. CYP3A4 is the principal member of the CYP450 enzyme family responsible for T-2 toxin metabolism. The metabolite produced by carboxylesterase is HT-2, and the metabolite produced by CYP 3A4 is 3’-OH T-2. The different metabolites show different toxicities. Our results will provide useful data concerning the toxic mechanism, the safety evaluation, and the health risk assessment of T-2 toxin.

  4. Development of T2-relaxation values in regional brain sites during adolescence.

    Science.gov (United States)

    Kumar, Rajesh; Delshad, Sean; Macey, Paul M; Woo, Mary A; Harper, Ronald M

    2011-02-01

    Brain tissue changes accompany multiple neurodegenerative and developmental conditions in adolescents. Complex processes that occur in the developing brain with disease can be evaluated accurately only against normal aging processes. Normal developmental changes in different brain areas alter tissue water content, which can be assessed by magnetic resonance (MR) T2 relaxometry. We acquired proton-density (PD) and T2-weighted images from 31 subjects (mean age±S.D., 17.4±4.9 years; 18 male), using a 3.0-T MR imaging scanner. Voxel-by-voxel T2-relaxation values were calculated, and whole-brain T2-relaxation maps constructed and normalized to a common space template. We created a set of regions of interest (ROIs) over cortical gray and white matter, basal ganglia, amygdala, thalamic, hypothalamic, pontine and cerebellar sites, with sizes of ROIs varying from 12 to 243 mm(3); regional T2-relaxation values were determined from these ROIs and normalized T2-relaxation maps. Correlations between R2 (1/T2) values in these sites and age were assessed with Pearson's correlation procedures, and gender differences in regional T2-relaxation values were evaluated with independent-samples t tests. Several brain regions, but not all, showed principally positive correlations between R2 values and age; negative correlations emerged in the cerebellar peduncles. No significant differences in T2-relaxation values emerged between males and females for those areas, except for the mid pons and left occipital white matter; males showed higher T2-relaxation values over females. The findings indicate that T2-relaxation values vary with development between brain structures, and emphasize the need to correct for such age-related effects during any determination of potential changes from control values.

  5. Percutaneous upper thoracic radiofrequency sympathectomy in Raynaud phenomenon: a comparison of T2/T3 procedure versus T2 lesion with phenol application.

    Science.gov (United States)

    Gabrhelik, Tomas; Michalek, Pavel; Adamus, Milan; Berta, Emil

    2009-01-01

    Percutaneous radiofrequency (RF) thoracic sympathectomy is an alternative method to surgical procedures for the treatment of acral ischemia in Raynaud phenomenon. The procedure is indicated if conservative therapy fails to provide sufficient relief. The aim of this study was to compare classic T2 and T3 RF thermolesioning with a less invasive procedure at the level of T2 only. Fifty adult patients, American Society of Anesthesiologists (ASA) classification I to III, were randomly assigned to 1 of 2 groups. T2 and T3 thoracic RF thermolesion was performed in 1 group, whereas T2 thermolesion with local application of 0.5 mL of 6% phenol was delivered in the second group. Changes in cold perception, pain, and quality of life were assessed using a questionnaire. Blood circulation in the upper extremity was evaluated using infrared thermography. Patients were observed for a period of 3 months. A significant decrease in pain according to visual analog scale (P Thoracic RF upper sympathectomy is an effective method in the treatment of resistant forms of Raynaud phenomenon. A single-shot procedure at the level of T2 may be preferable because of the shorter procedure duration of this technique.

  6. Visual analysis of serial T2-weighted MRI in multiple sclerosis: intra- and interobserver reproducibility

    Energy Technology Data Exchange (ETDEWEB)

    Molyneux, P.D.; Miller, D.H. [Inst. of Neurology, National Hospital Queen Square, London (United Kingdom); Filippi, M. [Neuroimaging Research Unit, Department of Neuroscience, Scientific Institute Ospedale San Raffaele, University of Milan, Milan (Italy); Yousry, T.A. [Department of Neuroradiology, Klinikum Grosshadern, Munich (Germany); Radue, E.W. [Department of Neuroradiology, Kantonsspital, Basel (Switzerland); Ader, H.J. [Department of Biostatistics, Vrije Universiteit, Academic Hospital of the Vrije Universiteit, Amsterdam (Netherlands); Barkhof, F. [MRI Centre for MS Research and Radiology, Academic Hospital of the Vrije Universiteit, Amsterdam (Netherlands)

    1999-12-01

    We evaluated the effect of consensus formation and training on the agreement between observers in scoring the number of new and enlarging multiple sclerosis (MS) lesions on serial T2-weighted MRI studies. The baseline and month 9 MRI studies of 16 patients with a range of MRI activity were used (dual-echo conventional spin-echo sequence, TR 2000, TE 34 and 90 ms, 5 mm contiguous slices, in-plane resolution 1 mm). First, the serial studies were visually analysed for the presence of new and enlarging lesions, on two occasions, by five experienced observers, without adopting any consensus strategy and in isolation. Next, the observers met to identify the common sources of inconsistencies in reporting between observers and formulate consensus rules. Finally, a further independent reading session was performed on the same MRI dataset, this time applying the consensus rules. Agreement between observers was assessed using kappa scores. Without the consensus rules, interobserver kappa scores for the first and second reading sessions for new lesions were only 0.51 and 0.39 respectively; agreement for enlarging lesions was even worse. The mean intraobserver kappa score for new lesions was higher at 0.72, reflecting the fact that the observers were consistently applying their individual assessment strategies. Application of the consensus rules did not lead to a significant improvement in inter observer kappas; the kappa scores adopting the guidelines were 0.46 and 0.21 for new and enlarging lesions respectively. Consensus guidelines thus did not improve the reproducibility of visual analysis of serial T2-weighted MRI, and the level of agreement between observers remained only moderate. Suboptimal repositioning is likely to be a major source of residual variability and this suggests a future role for image registration strategies; until then, a single observer, or pair of observers working in consensus, should be used in MS studies. (orig.)

  7. Development and production of the ionization chamber for the T2K muon monitor

    Energy Technology Data Exchange (ETDEWEB)

    Matsuoka, K., E-mail: matsuoka@scphys.kyoto-u.ac.j [Kyoto University, Kitashirakawa-Oiwake-cho Sakyo-ku, Kyoto 606-8502 (Japan); Ichikawa, A.; Kubo, H. [Kyoto University, Kitashirakawa-Oiwake-cho Sakyo-ku, Kyoto 606-8502 (Japan); Maruyama, T. [High Energy Accelerator Research Organization (KEK), Oho 1-1, Tsukuba 305-0801 (Japan); Murakami, A.; Nakaya, T.; Yokoyama, M. [Kyoto University, Kitashirakawa-Oiwake-cho Sakyo-ku, Kyoto 606-8502 (Japan)

    2010-11-01

    We report on the development of an ionization chamber for the muon monitor in the T2K (Tokai-to-Kamioka) long baseline neutrino oscillation experiment. In the T2K experiment, we generate a muon neutrino beam using the 50-GeV proton synchrotron in J-PARC and detect it in the Super-Kamiokande detector, which is 295 km away from J-PARC. We aim the neutrino beam off-axis by 2.5{sup o} from Super-Kamiokande in order to maximize the sensitivity to the neutrino oscillation measurement. Since the beam direction is required to be aimed within 1 mrad, we need to monitor it with a precision better than 1 mrad. The muon monitor is the only instrument that can monitor the neutrino beam direction in real time by measuring a profile of muons which are generated along with neutrinos. It is required to measure the intense muon beam precisely and stably in a high radiation area. Therefore, we use two independent systems for the muon monitor: an array of ionization chambers and another array of solid-state detectors. We developed the ionization chamber and performed beam tests with an electron beam at the Laboratory of Particle Beam Science in Kyoto University. We also had a long-term test in the NuMI beamline at Fermilab. Then we finalized the design of the ionization chamber and built it. We expect the ionization chambers as the muon monitor to monitor the beam direction with a precision of 0.2 mrad.

  8. Flow-independent T(2)-prepared inversion recovery black-blood MR imaging.

    Science.gov (United States)

    Liu, Chia-Ying; Bley, Thorsten A; Wieben, Oliver; Brittain, Jean H; Reeder, Scott B

    2010-01-01

    To develop a magnetization preparation method to achieve robust, flow-independent blood suppression for cardiac and vascular magnetic resonance imaging (MRI). T(2)Prep-IR sequence consists of a T(2) preparation followed by a nonselective adiabatic inversion pulse. T(2)Prep separates the initial longitudinal magnetization of arterial wall from lumen blood. After the inversion recovery pulse the imaging acquisition is then delayed for a period that allows the blood signal to approach the zero-crossing point. Compared to the conventional double inversion recovery (DIR) preparation, T(2)Prep-IR prepares all the spins regardless of their velocity and direction. T(2)Prep-IR was incorporated into the fast spin echo and fast gradient echo acquisition sequences and images in various planes were acquired in the carotid arteries, thoracic aorta, and heart of normal volunteers. Blood suppression and image quality were compared qualitatively between two different preparations. For in-plane flow carotid images, persistent flow-related artifacts on the DIR images were removed with T(2)Prep-IR. For cardiac applications, T(2)Prep-IR provided robust blood suppression regardless of the flow direction and velocity, including the cardiac long-axis views and the aorta that are often problematic with DIR. T(2)Prep-IR may overcome the flow dependence of DIR by providing robust flow-independent black-blood images. (c) 2009 Wiley-Liss, Inc.

  9. Quantitative T2 mapping of white matter: applications for ageing and cognitive decline

    Science.gov (United States)

    Knight, Michael J.; McCann, Bryony; Tsivos, Demitra; Dillon, Serena; Coulthard, Elizabeth; Kauppinen, Risto A.

    2016-08-01

    In MRI, the coherence lifetime T2 is sensitive to the magnetic environment imposed by tissue microstructure and biochemistry in vivo. Here we explore the possibility that the use of T2 relaxometry may provide information complementary to that provided by diffusion tensor imaging (DTI) in ageing of healthy controls (HC), Alzheimer’s disease (AD) and mild cognitive impairment (MCI). T2 and diffusion MRI metrics were quantified in HC and patients with MCI and mild AD using multi-echo MRI and DTI. We used tract-based spatial statistics (TBSS) to evaluate quantitative MRI parameters in white matter (WM). A prolonged T2 in WM was associated with AD, and able to distinguish AD from MCI, and AD from HC. Shorter WM T2 was associated with better cognition and younger age in general. In no case was a reduction in T2 associated with poorer cognition. We also applied principal component analysis, showing that WM volume changes independently of  T2, MRI diffusion indices and cognitive performance indices. Our data add to the evidence that age-related and AD-related decline in cognition is in part attributable to WM tissue state, and much less to WM quantity. These observations suggest that WM is involved in AD pathology, and that T2 relaxometry is a potential imaging modality for detecting and characterising WM in cognitive decline and dementia.

  10. Cross-Layer Optimization of DVB-T2 System for Mobile Services

    Directory of Open Access Journals (Sweden)

    Lukasz Kondrad

    2010-01-01

    In this paper, we address the question of how DVB-T2 transmission can be optimized for improved mobile broadcast reception. We investigate cross-layer optimization techniques with a focus on the transport of scalable video (SVC streams over DVB-T2 Physical Layer Pipes (PLP. Throughout the paper, we propose different optimization options and verify their utility.

  11. Imaging surface plasmon resonance detection for T-2 toxin in wheat

    Science.gov (United States)

    T-2 toxin is a trichothecene (Type A) mycotoxin harmful to humans and animals. It is produced by mainly Fusarium species, particularly F. sporotrichoides. Fusarium species often contaminate grains such as corn, wheat, barley, oats, rice and rye. T-2 toxin contamination in grains has been observed mo...

  12. T2 lesions and rate of progression of disability in multiple sclerosis

    NARCIS (Netherlands)

    Mostert, J. P.; Koch, M. W.; Steen, C.; Heersema, D. J.; de Groot, J. C.; De Keyser, J.

    2010-01-01

    Background and purpose: To assess the predictive value of T2 lesions on the rate of progression of disability in multiple sclerosis (MS). Methods: We reanalyzed T2 lesion number and load on brain MRI scans, performed before 1997, of 186 MS patients, who were clinically followed. There were 90 patien

  13. 44 CFR 402.6 - Relation to Transportation Order T-2.

    Science.gov (United States)

    2010-10-01

    ... Order T-2. 402.6 Section 402.6 Emergency Management and Assistance DEPARTMENT OF COMMERCE AND DEPARTMENT OF TRANSPORTATION SHIPMENTS ON AMERICAN FLAG SHIPS AND AIRCRAFT (T-1, INT. 1) § 402.6 Relation to Transportation Order T-2. Transportation Order T-1 applies to the transportation of commodities to, or in transit...

  14. 改进的T2-BIC说话人二级分割算法%Improved Two-stage T2-BIC Algorithm for Speaker Segmentation

    Institute of Scientific and Technical Information of China (English)

    郑继明; 司可宁

    2011-01-01

    This paper proposes an improved two-stage T2-BIC algorithm for speaker segmentation, because traditional T2-BIC algorithm has the problems of a bigger accumulated error and a lower recall ratio. In the first stage, the peak position of T2 statistic in search window is detected by using improved sliding variable-size analysis window, and Bayesian Information Criterion(BIC) algorithm is used to acknowledge the peaks. In the second stage, the idea of divide-and-conquer is used to detect the missed tums because of low BIC reliability. Experimental result shows that compared with other algorithms, the improved algorithm achieves better performance, and improves the precision, recall and F measure.%针对传统T2-BIC算法累积误差较大、召回率不高的问题,提出一种改进的T2-BIC说话人二级分割算法.第1级采用改进的滑动窗口检测搜索窗中的T2统计量峰值,利用贝叶斯信息准则(BIC)对峰值进行确认,第2级利用分步解决的思想处理由于BIC可信度过低而漏选的分割点.实验结果表明,与同类算法相比,该算法分割效果较好,准确率、召回率和综合性能都有所提高.

  15. Comprehensive Analysis of Yukawa Hierarchies on $T^2/Z_N$ with Magnetic Fluxes

    CERN Document Server

    Fujimoto, Yukihiro; Nishiwaki, Kenji; Sakamoto, Makoto; Tatsuta, Yoshiyuki

    2016-01-01

    Based on the result of classification in our previous work, we exhaustively investigate Yukawa sector of $U(8)$ model on magnetized orbifolds $T^{2}/Z_{2}$, $T^{2}/Z_{3}$, $T^{2}/Z_{4}$ and $T^{2}/Z_{6}$ by evaluating ratios of the mass eigenvalues of the three states in all the possible configurations with one and two Higgs pairs where three generations are realized in fermions. Because of smearing effect via kinetic mixing, one can realize a hierarchy such as $10^{-2}$-$10^{-3}$, but it is very difficult to achieve the mass ratio between the up and top quarks ($m_{\\text{up}}/m_{\\text{top}} \\sim 10^{-5}$) on the complicated magnetized orbifolds $T^{2}/Z_{N}\\,(N=3,4,6)$.

  16. T-2 Toxin-induced Toxicity in Pregnant Mice and Rats

    Directory of Open Access Journals (Sweden)

    Shinya Sehata

    2008-11-01

    Full Text Available T-2 toxin is a cytotoxic secondary fungal metabolite that belongs to the trichothecene mycotoxin family. This mycotoxin is a well known inhibitor of protein synthesis through its high binding affinity to peptidyl transferase, which is an integral part of the ribosomal 60s subunit, and it also inhibits the synthesis of DNA and RNA, probably secondary to the inhibition of protein synthesis. In addition, T-2 toxin is said to induce apoptosis in many types of cells bearing high proliferating activity. T-2 toxin readily passes the placenta and is distributed to embryo/fetal tissues, which include many component cells bearing high proliferating activity. This paper reviews the reported data related to T-2 toxin-induced maternal and fetal toxicities in pregnant mice and rats. The mechanisms of T-2 toxin-induced apoptosis in maternal and fetal tissues are also discussed in this paper.

  17. T2 effect of hemoglobin concentration: assessment with in vitro MR spectroscopy.

    Science.gov (United States)

    Hayman, L A; Ford, J J; Taber, K H; Saleem, A; Round, M E; Bryan, R N

    1988-08-01

    T2 values were measured at 0.23 and 4.7 T for deoxygenated blood samples (43%-73% O2 saturation) with hematocrits of 18%-100%. An increase in the hematocrit produced a marked reduction in T2 at both field strengths. Cell lysis did not abolish the T2 effect at either field strength. The authors conclude that the increase in hemoglobin concentration caused by formation of a retracted clot is a cause of the hypointense appearance of acute hemorrhage compared with brain on T2-weighted clinical magnetic resonance images. This is particularly important on low-field-strength systems, which are not sensitive to the T2 shortening effects of paramagnetic intracellular deoxyhemoglobin.

  18. Quantification of myocardial iron deficiency in nonischemic heart failure by cardiac T2* magnetic resonance imaging.

    Science.gov (United States)

    Nagao, Michinobu; Matsuo, Yoshio; Kamitani, Takeshi; Yonezawa, Masato; Yamasaki, Yuzo; Kawanami, Satoshi; Abe, Kohtaro; Mukai, Yasushi; Higo, Taiki; Yabuuchi, Hidetake; Takemura, Atsushi; Yoshiura, Takashi; Sunagawa, Kenji; Honda, Hiroshi

    2014-03-15

    The aim of this study was to use T2* cardiac magnetic resonance (CMR) imaging to quantify myocardial iron content in patients with heart failure (HF) and to investigate the relation between iron content, cardiac function, and the cause of HF. CMR data were analyzed from 167 patients with nonischemic and 31 with ischemic HF and 50 patients with normal ventricular function. Short-axis T2* imaging was accomplished using 3-T scanner and multiecho gradient-echo sequence. Myocardial T2* value (M-T2*) was calculated by fitting the signal intensity data for the mid-left ventricular (LV) septum to a decay curve. Patients with nonischemic HF were categorized into patients with LV ejection fraction (LVEF) iron deficiency and nonischemic HF. M-T2* is a biomarker that can predict adverse cardiac function in patients with nonischemic HF.

  19. Monitoring of VX2 tumor growth in rabbit liver using T2-weighted and dynamic contrast-enhanced magnetic resonance imaging at 1.5T

    Science.gov (United States)

    Jao, Jo-Chi; Mac, Ka-Wai; Chang, Chiung-Yun; Wu, Yu-Chiuan; Hsiao, Chia-Chi; Chen, Po-Chou

    2017-03-01

    This study aimed to investigate the VX2 tumor growth in rabbit liver using T2-weighted imaging (T2WI) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Five New Zealand white (NZW) rabbits were implanted with VX2 cell suspension in liver. Afterwards, MRI was performed 7, 14, 21 and 28 days after tumor implantation. A 1.5T clinical MRI scanner was used to perform scans. After 3-plane localizer, T1 weighted imaging (T1WI), T2WI, and DCE-MRI using a three-dimensional gradient echo pulse sequence was performed. After 4 pre-contrast images were acquired, each rabbit was injected i.v. with 0.1 mmol/kg Dotarem. The total scan time after Dotarem administration was 30 minutes. All acquired images were analyzed using ImageJ software. Several regions of interest were selected from the rims of tumor, liver, and muscle. The enhancement ratio (ER) was calculated by dividing the MR signal after Dotarem injection to the MR signal before Dotarem injection. The maximum ER (ER_max) value of tumor for each rabbit was observed right after the Dotarem injection. The T2W MR signal intensities (T2W_SI) and the ER_max values obtained 7, 14, 21 and 28 days after tumor implantation were analyzed with a linear regression algorithm. Both T2W_SI and ER_max of tumors increased with time. The changes for T2W_SI and ER_max of tumors between 7 and 28 days after tumor implantation were 32.66% and 18.14%, respectively. T2W_SI is more sensitive than ER_max for monitoring the growth of VX2 tumor in a rabbit liver model.

  20. Europium-engineered iron oxide nanocubes with high T1 and T2 contrast abilities for MRI in living subjects

    Science.gov (United States)

    Yang, Lijiao; Zhou, Zijian; Liu, Hanyu; Wu, Changqiang; Zhang, Hui; Huang, Guoming; Ai, Hua; Gao, Jinhao

    2015-04-01

    Magnetic resonance imaging (MRI) contrast agents with both positive (T1) and negative (T2) contrast abilities are needed in clinical diagnosis for fault-free accurate detection of lesions. We report a facile synthesis of europium-engineered iron oxide (EuIO) nanocubes as T1 and T2 contrast agents for MRI in living subjects. The Eu(iii) oxide-embedded iron oxide nanoparticles significantly increase the T1 relaxivity with an enhanced positive contrast effect. EuIO nanocubes with 14 nm in diameter showed a high r1 value of 36.8 mM-1 s-1 with respect to total metal ions (Fe + Eu), which is about 3 times higher than that of Fe3O4 nanoparticles with similar size. Moreover, both r1 and r2 values of EuIO nanocubes can be tuned by varying their sizes and Eu doping ratios. After citrate coating, EuIO nanocubes can provide enhanced T1 and T2 contrast effects in small animals, particularly in the cardiac and liver regions. This work may provide an insightful strategy to design MRI contrast agents with both positive and negative contrast abilities for biomedical applications.Magnetic resonance imaging (MRI) contrast agents with both positive (T1) and negative (T2) contrast abilities are needed in clinical diagnosis for fault-free accurate detection of lesions. We report a facile synthesis of europium-engineered iron oxide (EuIO) nanocubes as T1 and T2 contrast agents for MRI in living subjects. The Eu(iii) oxide-embedded iron oxide nanoparticles significantly increase the T1 relaxivity with an enhanced positive contrast effect. EuIO nanocubes with 14 nm in diameter showed a high r1 value of 36.8 mM-1 s-1 with respect to total metal ions (Fe + Eu), which is about 3 times higher than that of Fe3O4 nanoparticles with similar size. Moreover, both r1 and r2 values of EuIO nanocubes can be tuned by varying their sizes and Eu doping ratios. After citrate coating, EuIO nanocubes can provide enhanced T1 and T2 contrast effects in small animals, particularly in the cardiac and liver

  1. Texture analysis using proton density and T2 relaxation in patients with histological usual interstitial pneumonia (UIP) or nonspecific interstitial pneumonia (NSIP).

    Science.gov (United States)

    Buzan, Maria T A; Wetscherek, Andreas; Heussel, Claus Peter; Kreuter, Michael; Herth, Felix J; Warth, Arne; Kauczor, Hans-Ulrich; Pop, Carmen Monica; Dinkel, Julien

    2017-01-01

    The purpose of our study was to assess proton density (PD) and T2 relaxation time of usual interstitial pneumonia (UIP) and nonspecific interstitial pneumonia (NSIP) and to evaluate their utility in differentiating the two patterns. Furthermore, we aim to investigate whether these two parameters could help differentiate active-inflammatory and stable-fibrotic lesions in NSIP. 32 patients (mean age: 69 years; M:F, 1:1) with pathologically proven disease (UIP:NSIP, 1:1), underwent thoracic thin-section multislice CT scan and 1.5T MRI. A total of 437 regions-of-interest (ROIs) were classified at CT as advanced, moderate or mild alterations. Based on multi-echo single-shot TSE sequence acquired at five echo times, with breath-holding at end-expiration and ECG-triggering, entire lung T2 and PD maps were generated from each subject. The T2 relaxation time and the respective signal intensity were quantified by performing a ROI measurement on the T2 and PD maps in the corresponding CT selected areas of the lung. UIP and NSIP regional patterns could not be differentiated by T2 relaxation times or PD values alone. Overall, a strong positive correlation was found between T2 relaxation and PD in NSIP, r = 0.64, prelaxation showed significant statistical difference between active-inflammatory and stable-fibrotic NSIP regions at all levels, p0.05. T2 relaxation times and PD values may provide helpful quantitative information for differentiating NSIP from UIP pattern. These parameters have the potential to differentiate active-inflammatory and stable-fibrotic lesions in NSIP.

  2. T2-weighted four dimensional magnetic resonance imaging with result-driven phase sorting

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yilin; Yin, Fang-Fang; Cai, Jing, E-mail: jing.cai@duke.edu [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27710 and Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Czito, Brian G. [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Bashir, Mustafa R. [Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710 (United States)

    2015-08-15

    Purpose: T2-weighted MRI provides excellent tumor-to-tissue contrast for target volume delineation in radiation therapy treatment planning. This study aims at developing a novel T2-weighted retrospective four dimensional magnetic resonance imaging (4D-MRI) phase sorting technique for imaging organ/tumor respiratory motion. Methods: A 2D fast T2-weighted half-Fourier acquisition single-shot turbo spin-echo MR sequence was used for image acquisition of 4D-MRI, with a frame rate of 2–3 frames/s. Respiratory motion was measured using an external breathing monitoring device. A phase sorting method was developed to sort the images by their corresponding respiratory phases. Besides, a result-driven strategy was applied to effectively utilize redundant images in the case when multiple images were allocated to a bin. This strategy, selecting the image with minimal amplitude error, will generate the most representative 4D-MRI. Since we are using a different image acquisition mode for 4D imaging (the sequential image acquisition scheme) with the conventionally used cine or helical image acquisition scheme, the 4D dataset sufficient condition was not obviously and directly predictable. An important challenge of the proposed technique was to determine the number of repeated scans (N{sub R}) required to obtain sufficient phase information at each slice position. To tackle this challenge, the authors first conducted computer simulations using real-time position management respiratory signals of the 29 cancer patients under an IRB-approved retrospective study to derive the relationships between N{sub R} and the following factors: number of slices (N{sub S}), number of 4D-MRI respiratory bins (N{sub B}), and starting phase at image acquisition (P{sub 0}). To validate the authors’ technique, 4D-MRI acquisition and reconstruction were simulated on a 4D digital extended cardiac-torso (XCAT) human phantom using simulation derived parameters. Twelve healthy volunteers were involved

  3. RETRACTED: Association between the ACE I/D gene polymorphism and T2DN susceptibility: The risk of T2DM developing into T2DN in the Asian population.

    Science.gov (United States)

    Zhong, Weiqiang; Jiang, Zongpei; Zhou, Tian-Biao

    2015-12-01

    This article has been included in a multiple retraction: Weiqiang Zhong, Zongpei Jiang, and Tian-Biao Zhou Association between the ACE I/D gene polymorphism and T2DN susceptibility: The risk of T2DM developing into T2DN in the Asian population Journal of Renin-Angiotensin-Aldosterone System 1470320314566019, first published on January 26, 2015 doi: 10.1177/1470320314566019 This article has been retracted at the request of the Editors and the Publisher. After conducting a thorough investigation, SAGE found that the submitting authors of a number of papers published in the Journal of the Renin-Angiotensin Aldosterone System ( JRAAS) (listed below) had supplied fabricated contact details for their nominated reviewers. The Editors accepted these papers based on the reports supplied by the individuals using these fake reviewer email accounts. After concluding that the peer review process was therefore seriously compromised, SAGE and the journal Editors have decided to retract all affected articles. Online First articles (these articles will not be published in an issue) Wenzhuang Tang, Tian-Biao Zhou, and Zongpei Jiang Association of the angiotensinogen M235T gene polymorphism with risk of diabetes mellitus developing into diabetic nephropathy Journal of Renin-Angiotensin-Aldosterone System 1470320314563426, first published on December 18, 2014 doi: 10.1177/1470320314563426 Tian-Biao Zhou, Hong-Yan Li, Zong-Pei Jiang, Jia-Fan Zhou, Miao-Fang Huang, and Zhi-Yang Zhou Role of renin-angiotensin-aldosterone system inhibitors in radiation nephropathy Journal of Renin-Angiotensin-Aldosterone System 1470320314563424, first published on December 18, 2014 doi: 10.1177/1470320314563424 Weiqiang Zhong, Zongpei Jiang, and Tian-Biao Zhou Association between the ACE I/D gene polymorphism and T2DN susceptibility: The risk of T2DM developing into T2DN in the Asian population Journal of Renin-Angiotensin-Aldosterone System 1470320314566019, first published on January 26, 2015 doi: 10

  4. 磁共振FSE-T2WI、FLAIR-T2WI及增强扫描对脑实质囊虫病诊断价值%The value of FSE-T2WI,FLAIR-T2WI and enhancement scan in diagnosing neurocysticercosis

    Institute of Scientific and Technical Information of China (English)

    张承志; 邱麟; 许俊锋; 唐艳隆; 查文金; 冉令甲

    2013-01-01

    目的 研究磁共振FSE-T2WI、FLAIR-T2WI及增强扫描对脑实质囊虫病诊断价值.方法分析76例脑实质囊虫患者磁共振FSE-T2WI、FLAIR-T2WI及增强扫描序列MRI表现,及其各序列检出囊泡、头节、颗粒状肉芽肿、灶周水肿及钙化灶的数目,并进行统计学处理.结果脑实质囊虫病病理分期为囊泡期28例,退变死亡期25例,死亡钙化期16例,混合期7例,与MRI表现相一致,囊泡在FSE-T2WI检出率最高为98%,头节在FLAIR-T2WI检出率最高为95%,颗粒状肉芽肿增强扫描检出率最高为93%,灶周水肿在FLAIR-T2WI检出率最高为97%,钙化灶在FSE-T2WI检出率相对较高为76%.结论 MRI表现能明确反映脑实质囊虫病的病理变化过程,合理有效地选择磁共振FSE-T2WI、FLAIR-T2WI及T1WI增强扫描等不同序列的检查,对脑实质囊虫病病灶检出和诊断具有十分重要的价值.

  5. Prostate cancer pathologic stage pT2b (2002 TNM staging system: does it exist?

    Directory of Open Access Journals (Sweden)

    Maisa M. Quintal

    2006-02-01

    Full Text Available OBJECTIVE: In the 1997 TNM staging system, tumors were classified into a single subdivision: T2a, and bilateral tumor involvement (T2b. In the 2002 TNM staging system, tumors are subclassified as T2a (less than one half of one lobe involvement, T2b (more than one half of one lobe involvement, and T2c (bilateral involvement. A recent study questioned the existence of a true pathologic pT2b tumor. The aim of our study is to verify this question. MATERIALS AND METHODS: The study population consisted of 224 men submitted to radical retropubic prostatectomy. The surgical specimens were histologically evaluated by complete embedding and whole-mount processing. Tumor extent was evaluated by a point-count method. The surgical specimens were staged according to the 2002 TNM staging system. RESULTS: Using the 2002 TNM criteria, the surgical specimens were classified as pT2a, 28 (12.50%; pT2b, 0 (0%; pT2c, 138 (61.61%; pT3a, 30 (13.39%; and, pT3b, 28 (12.50%. Using the point-count method for tumor extent evaluation, the minimum and maximum total points obtained in unilateral tumors were 192 and 368 points, respectively; the most extensive unilateral tumor showed 68 positive points (less than half the minimum total point-count. CONCLUSIONS: Using the point-count method for tumor extent, our study questions a real existence for pathologic stage pT2b tumors (unilateral tumors involving greater than one-half of one lobe.

  6. T2-weighted MRI signal predicts hormone and tumor responses to somatostatin analogs in acromegaly.

    Science.gov (United States)

    Potorac, Iulia; Petrossians, Patrick; Daly, Adrian F; Alexopoulou, Orsalia; Borot, Sophie; Sahnoun-Fathallah, Mona; Castinetti, Frederic; Devuyst, France; Jaffrain-Rea, Marie-Lise; Briet, Claire; Luca, Florina; Lapoirie, Marion; Zoicas, Flavius; Simoneau, Isabelle; Diallo, Alpha M; Muhammad, Ammar; Kelestimur, Fahrettin; Nazzari, Elena; Centeno, Rogelio Garcia; Webb, Susan M; Nunes, Marie-Laure; Hana, Vaclav; Pascal-Vigneron, Véronique; Ilovayskaya, Irena; Nasybullina, Farida; Achir, Samia; Ferone, Diego; Neggers, Sebastian J C M M; Delemer, Brigitte; Petit, Jean-Michel; Schöfl, Christof; Raverot, Gerald; Goichot, Bernard; Rodien, Patrice; Corvilain, Bernard; Brue, Thierry; Schillo, Franck; Tshibanda, Luaba; Maiter, Dominique; Bonneville, Jean-François; Beckers, Albert

    2016-11-01

    GH-secreting pituitary adenomas can be hypo-, iso- or hyper-intense on T2-weighted MRI sequences. We conducted the current multicenter study in a large population of patients with acromegaly to analyze the relationship between T2-weighted signal intensity on diagnostic MRI and hormonal and tumoral responses to somatostatin analogs (SSA) as primary monotherapy. Acromegaly patients receiving primary SSA for at least 3 months were included in the study. Hormonal, clinical and general MRI assessments were performed and assessed centrally. We included 120 patients with acromegaly. At diagnosis, 84, 17 and 19 tumors were T2-hypo-, iso- and hyper-intense, respectively. SSA treatment duration, cumulative and mean monthly doses were similar in the three groups. Patients with T2-hypo-intense adenomas had median SSA-induced decreases in GH and IGF-1 of 88% and 59% respectively, which were significantly greater than the decreases observed in the T2-iso- and hyper-intense groups (P < 0.001). Tumor shrinkage on SSA was also significantly greater in the T2-hypo-intense group (38%) compared with the T2-iso- and hyper-intense groups (8% and 3%, respectively; P < 0.0001). The response to SSA correlated with the calculated T2 intensity: the lower the T2-weighted intensity, the greater the decrease in random GH (P < 0.0001, r = 0.22), IGF-1 (P < 0.0001, r = 0.14) and adenoma volume (P < 0.0001, r = 0.33). The T2-weighted signal intensity of GH-secreting adenomas at diagnosis correlates with hormone reduction and tumor shrinkage in response to primary SSA treatment in acromegaly. This study supports its use as a generally available predictive tool at diagnosis that could help to guide subsequent treatment choices in acromegaly. © 2016 Society for Endocrinology.

  7. Scintillator counters with multi-pixel avalanche photodiode readout for the ND280 detector of the T2K experiment

    Energy Technology Data Exchange (ETDEWEB)

    Mineev, O. [Institute for Nuclear Research of RAS, INR RAS, 60th October Revolution Pr. 7a, 117312 Moscow (Russian Federation)]. E-mail: oleg@inr.ru; Afanasjev, A. [Institute for Nuclear Research of RAS, INR RAS, 60th October Revolution Pr. 7a, 117312 Moscow (Russian Federation); Bondarenko, G.; Golovin, V. [Center of Perspective Technology and Apparatus, 107076 Moscow (Russian Federation); Gushchin, E.; Izmailov, A.; Khabibullin, M.; Khotjantsev, A. [Institute for Nuclear Research of RAS, INR RAS, 60th October Revolution Pr. 7a, 117312 Moscow (Russian Federation); Kudenko, Yu. [Institute for Nuclear Research of RAS, INR RAS, 60th October Revolution Pr. 7a, 117312 Moscow (Russian Federation); Kurimoto, Y. [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Kutter, T. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803-4001 (United States); Lubsandorzhiev, B. [Institute for Nuclear Research of RAS, INR RAS, 60th October Revolution Pr. 7a, 117312 Moscow (Russian Federation); Mayatski, V. [AO Uniplast, 600016 Vladimir (Russian Federation); Musienko, Yu. [Institute for Nuclear Research of RAS, INR RAS, 60th October Revolution Pr. 7a, 117312 Moscow (Russian Federation); Nakaya, T.; Nobuhara, T. [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Shaibonov, B.A.J.; Shaikhiev, A. [Institute for Nuclear Research of RAS, INR RAS, 60th October Revolution Pr. 7a, 117312 Moscow (Russian Federation); Taguchi, M. [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Yershov, N. [Institute for Nuclear Research of RAS, INR RAS, 60th October Revolution Pr. 7a, 117312 Moscow (Russian Federation); Yokoyama, M. [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan)

    2007-07-11

    The Tokai-to-Kamioka (T2K) experiment is a second generation long baseline neutrino oscillation experiment which aims at a sensitive search for {nu}{sub e} appearance. The main design features of the T2K near neutrino detectors located at 280m from the target are presented, and the scintillator counters are described. The counters are readout via WLS fibers embedded into S-shaped grooves in the scintillator from both ends by multi-pixel avalanche photodiodes operating in a limited Geiger mode. Operating principles and results of tests of photosensors with a sensitive area of 1mm{sup 2} are presented. A time resolution of 1.75ns, a spatial resolution of 9.9-12.4cm, and a detection efficiency for minimum ionizing particles of more than 99% were obtained for scintillator detectors in a beam test.

  8. Rapid Simultaneous Mapping of Total and Myelin Water Content, T1 and T2* in Multiple Sclerosis

    CERN Document Server

    Arhelger, Volker; Gliedstein, Detlef; Lafontaine, Marie-Sofie; Tonkova, Vyara; Holz, Dietrich; Böer, Andreas; Schenk, Jochen; Neeb, Heiko; (,; Koblenz, University of Applied Sciences; Koblenz, Radiologisches Institut Hohenzollernstrasse; Engineering, Institute for Medical; Koblenz, Information Processing; Boeer, Neurologie Dr; Koblenz,

    2010-01-01

    Quantitative magnetic resonance imaging might provide a more specific insight into disease process, progression and therapeutic response of multiple sclerosis. We present an extension of a previously published approach for the simultaneous mapping of brain T1, T2* and total water content. In addition to those three parameters, the method presented in the current work allows for the measurement of myelin bound water content, a surrogate marker of tissue myelination. Myelin water was measured based on its distinct relaxation with reduced T2*, resulting in a multiexponential decay signal. However, only 10 points could be acquired on the relaxation curve within a maximum echo time of <40ms as the quantitative protocol has been adapted previously for fast acquisitions with whole brain coverage. The sparse sampling required an adaption of the optimisation approach with additional constraints necessary in order to obtain reliable results. Therefore, the corresponding pool fractions were determined using linear op...

  9. Detecting Acute Myocardial Infarction by Diffusion-Weighted versus T2-Weighted Imaging and Myocardial Necrosis Markers

    Science.gov (United States)

    Chen, Min; Li, Yongjun; Wang, YaLing; Zhang, Shijun; Wang, Zhen; Wang, Lin; Ju, Shenghong

    2016-01-01

    We used a porcine model of acute myocardial infarction to study the signal evolution of ischemic myocardium on diffusion-weighted magnetic resonance images (DWI). Eight Chinese miniature pigs underwent percutaneous left anterior descending or left circumflex coronary artery occlusion for 90 minutes followed by reperfusion, which induced acute myocardial infarction. We used DWI preprocedurally and hourly for 4 hours postprocedurally. We acquired turbo inversion recovery magnitude T2-weighted images (TIRM T2WI) and late gadolinium enhancement images from the DWI slices. We measured the serum myocardial necrosis markers myoglobin, creatine kinase-MB isoenzyme, and cardiac troponin I at the same time points as the magnetic resonance scanning. We used histochemical staining to confirm injury. All images were analyzed qualitatively. Contrast-to-noise ratio (the contrast between infarcted and healthy myocardium) and relative signal index were used in quantitative image analysis. We found that DWI identified myocardial signal abnormity early (clinical serologic biomarkers.

  10. The Metabolic Fate of Tritium-Labeled T-2 Toxin, a Trichothecene Mycotoxin, in Swine.

    Science.gov (United States)

    Corley, Richard Allen

    The metabolic fate of T-2 toxin was determined in two female crossbred swine following the intravascular administration of one millicurie of tritium-labeled T-2 toxin at a nonlethal dose of 0.15 mg/kg body weight. The plasma elimination phase half-life was 90 minutes for total tritium residues. A total of 13.1 and 1.3 percent of the administered dose was found in the gall bladders in addition to 17.9 and 42.5 percent in the urine of the two pigs, S1 and S2, respectively, 4 hours after dosing. Free metabolites, identified by thin-layer chromatography, represented less than 20 and 30 percent of the metabolite residues in bile and urine, respectively, with the parent compound, T-2 toxin, never exceeding 0.25 percent. The major free metabolites were 3'-OH HT-2 and T-2 triol. Glucuronide conjugates represented 63 and 77 percent of the metabolite residues in urine and bile, respectively. The major conjugated metabolites were glucuronides of HT-2, 3'-OH T-2, 3'-OH HT-2 and T-2 toxin. Neosolaniol, 4-deacetyl-neosolaniol and T-2 tetraol were also identified in addition to 3 unknown metabolites. In the tissues, the greatest amount of radioactivity was located in the gastrointestinal tract (15.5 and 24.1 percent of the dose for the 2 pigs, S1 and S2, respectively). The remaining tissues sampled accounted for approximately 5 percent of the dose for the 2 pigs. Twenty-one metabolites were identified in tissues following reverse phase HPLC radiochromatography. Approximately 55 percent of the extractable radioactivity in the tissues, including the gastrointestinal tract, of both pigs corresponded to T-2 toxin, HT-2, deepoxy HT-2, T-2 triol, deepoxy T-2 triol, 3'-OH T-2, 3'-OH HT -2, T-2 tetraol and deepoxy T-2 tetraol. The major metabolite in tissues, PM-XV, did not correspond to any standard and represented an additional 27 percent of the extractable radioactivity.

  11. Intracellular and extracellular T1 and T2 relaxivities of magneto-optical nanoparticles at experimental high fields.

    Science.gov (United States)

    Klug, Gert; Kampf, Thomas; Bloemer, Steffen; Bremicker, Johannes; Ziener, Christian H; Heymer, Andrea; Gbureck, Uwe; Rommel, Eberhard; Nöth, Ulrich; Schenk, Wolfdieter A; Jakob, Peter M; Bauer, Wolfgang R

    2010-12-01

    This study reports the T(1) and T(2) relaxation rates of rhodamine-labeled anionic magnetic nanoparticles determined at 7, 11.7, and 17.6 T both in solution and after cellular internalization. Therefore cells were incubated with rhodamine-labeled anionic magnetic nanoparticles and were prepared at decreasing concentrations. Additionally, rhodamine-labeled anionic magnetic nanoparticles in solution were used for extracellular measurements. T(1) and T(2) were determined at 7, 11.7, and 17.6 T. T(1) times were determined with an inversion-recovery snapshot-flash sequence. T(2) times were obtained from a multispin-echo sequence. Inductively coupled plasma-mass spectrometry was used to determine the iron content in all samples, and r(1) and r(2) were subsequently calculated. The results were then compared with cells labeled with AMI-25 and VSOP C-200. In solution, the r(1) and r(2) of rhodamine-labeled anionic magnetic nanoparticles were 4.78/379 (7 T), 3.28/389 (11.7 T), and 2.00/354 (17.6 T). In cells, the r(1) and r(2) were 0.21/56 (7 T), 0.19/37 (11.7 T), and 0.1/23 (17.6 T). This corresponded to an 11- to 23-fold decrease in r(1) and an 8- to 15-fold decrease in r(2) . A decrease in r(1) was observed for AMI-25 and VSOP C-200. AMI-25 and VSOP exhibited a 2- to 8-fold decrease in r(2) . In conclusion, cellular internalization of iron oxide nanoparticles strongly decreased their T(1) and T(2) potency. Copyright © 2010 Wiley-Liss, Inc.

  12. On the Labile Memory Buffer in the Attentional Blink: Masking the T2 Representation by Onset Transients Mediates the AB

    Science.gov (United States)

    Jannati, Ali; Spalek, Thomas M.; Di Lollo, Vincent

    2011-01-01

    Report of a second target (T2) is impaired when presented within 500 ms of the first (T1). This attentional blink (AB) is known to cause a delay in T2 processing during which T2 must be stored in a labile memory buffer. We explored the buffer's characteristics using different types of masks after T2. These characteristics were inferred by…

  13. On the Labile Memory Buffer in the Attentional Blink: Masking the T2 Representation by Onset Transients Mediates the AB

    Science.gov (United States)

    Jannati, Ali; Spalek, Thomas M.; Di Lollo, Vincent

    2011-01-01

    Report of a second target (T2) is impaired when presented within 500 ms of the first (T1). This attentional blink (AB) is known to cause a delay in T2 processing during which T2 must be stored in a labile memory buffer. We explored the buffer's characteristics using different types of masks after T2. These characteristics were inferred by…

  14. Electrophysiological response of chicken's jejunal epithelium to increasing levels of T-2 toxin.

    Science.gov (United States)

    Yunus, Agha Waqar; Kröger, Susan; Tichy, Alexander; Zentek, Jürgen; Böhm, Josef

    2013-02-01

    The present investigations were conducted to test the effects of T-2 toxin on electrophysiological variables of jejunal epithelium of chicken. Jejunal segments of broilers were monitored in Ussing chambers in the presence of T-2 toxin at the levels of 0 (negative control), 0 (methanol/vehicle control), 0.1, 1, 5, and 10 μg/ml of buffer. T-2 toxin did not affect basal values of short circuit current (I(sc)), transmural potential difference, or tissue conductivity in the jejunal epithelium. T-2 toxin also did not statistically affect glucose-induced electrophysiological variables during the first 3 min of glucose induction. Compared to the vehicle control, the ouabain-sensitive I(sc) was negatively affected (P = 0.008) only under 5 μg of T-2 toxin/ml. Increasing levels of T-2 toxin negatively affected the ouabain-sensitive I(sc) in a cubic (P = 0.007) fashion. These data indicate that acute exposure to moderate levels of T-2 toxin may progressively impair the cation gradient across the jejunal epithelium.

  15. Intensity of prolactinoma on T2-weighted magnetic resonance imaging: towards another gender difference

    Energy Technology Data Exchange (ETDEWEB)

    Kreutz, Julie [University Hospital Sart-Tilman, Department of Radiology, Liege (Belgium); Centre Hospitalier Universitaire de Liege, Domaine Universitaire du Sart Tilman, Service d' Imagerie Medicale, Liege (Belgium); Vroonen, Laurent; Petrossians, Patrick; Rostomyan, Liliya; Beckers, Albert [University Hospital Sart-Tilman, Department of Endocrinology, Liege (Belgium); Cattin, Francoise [University Hospital Besancon, Department of Radiology, Besancon (France); Thiry, Albert [University Hospital Sart-Tilman, Department of Pathology, Liege (Belgium); Tshibanda, Luaba [University Hospital Sart-Tilman, Department of Radiology, Liege (Belgium); Bonneville, Jean-Francois [University Hospital Sart-Tilman, Department of Radiology, Liege (Belgium); University Hospital Sart-Tilman, Department of Endocrinology, Liege (Belgium)

    2015-07-15

    Clinical presentations of prolactinomas are quite different between genders. In comparison with women's prolactinoma, those in men showed predominance of large tumors with high prolactin (PRL) levels. This preponderance could be attributed to a greater proliferative potential of the tumors. Differences in magnetic resonance imaging (MRI) signal at diagnosis have not been yet clearly evaluated. We conduct a retrospective study comparing MRI signal intensity (SI) on T2-weighted images (T2-WI) between 41 men and 41 women to investigate whether or not men prolactinoma present specific features. In addition to the size of the adenoma and PRL levels (P < 0001), prolactinomas in men also exhibit differences from those in women in signal on T2-WI on MRI (P < 0001). Women's prolactinomas are mostly of high SI on T2-WI while men's prolactinomas exhibit a more heterogeneous pattern of SI on T2-WI. Prolactinomas presenting with low SI on T2-WI are almost exclusively encountered in men. Presence of T2-WI hypointensities in pituitary adenoma can be predictive of a different subtype of prolactinoma almost encountered in men and possibly translate the presence of spherical amyloid deposits, in agreement with the literature. (orig.)

  16. T2* magnetic resonance imaging of the liver in thalassemic patients in Iran

    Institute of Scientific and Technical Information of China (English)

    Farhad Zamani; Sara Razmjou; Shahram Akhlaghpoor; Seyyedeh-Masoomeh Eslami; Azita Azarkeivan; Afsaneh Amiri

    2011-01-01

    AIM: To investigate the accuracy of T2*-weighted magnetic resonance imaging (MRI T2*) in the evaluation of iron overload in beta-thalassemia major patients. METHODS: In this cross-sectional study, 210 patients with beta-thalassemia major having regular blood transfusions were consecutively enrolled. Serum ferritin levels were measured, and all patients underwent MRI T2* of the liver. Liver biopsy was performed in 53 patients at an interval of no longer than 3 mo after the MRIT2* in each patient. The amount of iron was assessed in both MRI T2* and liver biopsy specimens of each patient. RESULTS: Patients' ages ranged from 8 to 54 years with a mean of 24.59 ± 8.5 years. Mean serum ferritin level was 1906 ± 1644 ng/mL. Liver biopsy showed a moderate negative correlation with liver MRI T2* (r = -0.573, P = 0.000) and a low positive correlation with ferritin level (r = 0.350, P = 0.001). Serum ferritin levels showed a moderate negative correlation with liver MRI T2* values (r = -0.586, P = 0.000). CONCLUSION: Our study suggests that MRI T2* is a non-invasive, safe and reliable method for detecting iron load in patients with iron overload. . 2011 Baishideng. All rights reserved.

  17. MR fluid-attenuated inversion recovery imaging as routine brain T2-weighted imaging

    Energy Technology Data Exchange (ETDEWEB)

    Arakia, Yutaka; Ashikaga, Ryuichiro; Fujii, Koichi; Nishimura, Yasumasa; Ueda, Jun; Fujita, Norihiko

    1999-11-01

    We tried to investigate if magnetic resonance (MR) fluid-attenuated inversion recovery (FLAIR) imaging can be used as a routine brain screening examination instead of spin-echo T2-weighted imaging. Three hundred and ninety-four patients with clinically suspected brain diseases were randomly selected and examined with both brain MR FLAIR and T2-weighted imaging on the axial plane. These two imaging techniques were evaluated by two neuroradiologists as to which imaging was better for routine brain T2-weighted imaging. In 123 of 394 cases (31%), FLAIR imaging was superior to spin-echo T2-weighted imaging. Especially in cases with inflammatory diseases, traumatic diseases and demyelinating diseases, FLAIR imaging was particularly useful. Small lesions bordering cerebrospinal fluid (CSF) are often detected only by FLAIR imaging. In 259 cases (66%), including 147 normal cases (37%), they were equally evaluated. Only in 12 cases (3%) was conventional T2-weighted imaging superior to FLAIR imaging. Cerebrovascular lesions like cerebral aneurysm and Moyamoya disease could not be detected on FLAIR images because these structures were obscured by a low signal from the CSF. Also, because old infarctions tend to appear as low signal intensity on FLAIR images, the condition was sometimes hard to detect. Finally, FLAIR imaging could be used as routine brain T2-weighted imaging instead of conventional spin-echo T2-weighted imaging if these vascular lesions were watched.

  18. T2' imaging of native kidneys and renal allografts. A feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Mathys, C.; Blondin, D.; Wittsack, H.J.; Miese, F.R.; Rybacki, K.; Walther, C.; Holstein, A.; Lanzman, R.S. [Universitaetsklinikum Duesseldorf (Germany). Inst. fuer Radiologie

    2011-02-15

    Purpose: To evaluate the feasibility of T2' mapping in native kidneys and renal allografts. Materials and Methods: Following approval of the local ethics committee, 24 renal allograft recipients and 10 control subjects (healthy volunteers) were included in this study. Multi-echo T2 and T2{sup *} imaging was performed on a 1.5 Tesla scanner. Allograft recipients were assigned to two groups: group (a), 8 patients with good (glomerular filtration rate of more than 40 ml/min) allograft function and no evidence of transplant rejection, transplant renal artery stenosis or ureteral obstruction; group (b), 16 patients with deterioration of renal graft function (glomerular filtration rate (GFR) of 40 ml/min or less). Two different imaging protocols were tested. Results: The mean T2' relaxation parameters were 108.33 msec {+-} 13.34, 100.00 msec {+-} 18.89 and 124.57 msec {+-} 6.51 for groups (a), (b) and for control subjects, respectively. The reduction of T2' values in patient group (b) was not statistically significant. However, significant correlations could be demonstrated between T2' values and the glomerular filtration rate (GFR) of renal allograft function. The reproducibility was tested and the coefficients of variation of T2' values in the cortex of transplanted kidneys were 11.1 % within subjects and 11.3 % between subjects. Conclusion: Our results indicate that T2' imaging is a promising non-enhanced technique, which seems to reveal information on transplant function. Further studies are required to determine the clinical value of T2' mapping for monitoring renal allograft recipients. (orig.)

  19. Initial results from the rebuilt EXTRAP T2R RFP device

    Science.gov (United States)

    Brunsell, P. R.; Bergsåker, H.; Cecconello, M.; Drake, J. R.; Gravestijn, R. M.; Hedqvist\\ad{2 }, A.; Malmberg, J.-A.

    2001-11-01

    The EXTRAP T2R thin shell reversed-field pinch (RFP) device has recently resumed operation after a major rebuild including the replacement of the graphite armour with molybdenum limiters, a fourfold increase of the shell time constant, and the replacement of the helical coil used for the toroidal field with a conventional solenoid-type coil. Wall-conditioning using hydrogen glow discharge cleaning was instrumental for successful RFP operation. Carbon was permanently removed from the walls during the first week of operation. The initial results from RFP operation with relatively low plasma currents in the range Ip = 70-100 kA are reported. RFP discharges are sustained for more than three shell times. Significant improvements in plasma parameters are observed, compared to operation before the rebuild. There is a substantial reduction in the carbon impurity level. The electron density behaviour is more shot-to-shot reproducible. The typical density is ne = 0.5-1×1019 m-3. Monitors of Hα line radiation indicate that the plasma wall interaction is more toroidally symmetric and that there is less transient gas release from the wall. The minimum loop voltage is in the range Vt = 28-35 V, corresponding to a reduction by a factor of two to three compared to the value before the rebuild.

  20. Future asymptotics and geodesic completeness of polarized T2-symmetric spacetimes with weak regularity

    CERN Document Server

    LeFloch, Philippe G

    2014-01-01

    We investigate the late-time asymptotics of future expanding, polarized vacuum Einstein spacetimes with T2-symmetry on T3, which, by definition, admit two spacelike Killing fields. Our main result is the existence of a stable asymptotic regime within this class, that is, we provide here a full description of the late-time asymptotics of the solutions to the Einstein equations when the initial data set is close to the asymptotic regime. Our proof is based on several energy functionals with lower order corrections (as is standard for such problems) and the derivation of a simplified model which we exhibit here. Roughly speaking, the Einstein equations in the symmetry class under consideration consists of a system of wave equations coupled to constraint equations plus a system of ordinary differential equations. The unknowns involved in the system of ordinary equations are blowing up in the future timelike directions. One of our main contributions is the derivation of novel effective equations for suitably renor...

  1. Quantitative T2{sup *} assessment of knee joint cartilage after running a marathon

    Energy Technology Data Exchange (ETDEWEB)

    Hesper, Tobias [University Düsseldorf, Medical Faculty, Department of Orthopaedics, Düsseldorf (Germany); Miese, Falk R. [University Düsseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Düsseldorf (Germany); Hosalkar, Harish S. [Center of Hip Preservation and Children' s Orthopaedics, San Diego, CA (United States); Behringer, Michael [German Sport University, Cologne (Germany); Zilkens, Christoph [University Düsseldorf, Medical Faculty, Department of Orthopaedics, Düsseldorf (Germany); Antoch, Gerald [University Düsseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Düsseldorf (Germany); Krauspe, Rüdiger [University Düsseldorf, Medical Faculty, Department of Orthopaedics, Düsseldorf (Germany); Bittersohl, Bernd, E-mail: bbittersohl@partners.org [University Düsseldorf, Medical Faculty, Department of Orthopaedics, Düsseldorf (Germany)

    2015-02-15

    Highlights: • This is the first descriptive report on the effects of repetitive joint loading on the T2{sup **} relaxation assessment of articular cartilage. • This study on marathon runners who underwent MRI within 48 hours prior to and following the running event as well as after a period of convalescence of approximately four weeks confirms the feasibility of T2{sup **} mapping of knee joint cartilage under the consideration of repetitive joint loading prior to MRI as we noted only small differences in the T2{sup **} after running a marathon. • Despite the small study group (nn = 10) and the presence of morphologically normal appearing cartilage, we noted lower cartilage T2{sup **} values in the medial tibial plateau that may be related to functional demand or early signs of cartilage degeneration. - Abstract: Objective: To study the effect of repetitive joint loading on the T2{sup *} assessment of knee joint cartilage. Materials and methods: T2{sup *} mapping was performed in 10 non-professional marathon runners (mean age: 28.7 ± 3.97 years) with no morphologically evident cartilage damage within 48 h prior to and following the marathon and after a period of approximately four weeks. Bulk and zonal T2{sup *} values at the medial and lateral tibiofemoral compartment and the patellofemoral compartment were assessed by means of region of interest analysis. Pre- and post-marathon values were compared. Results: There was a small increase in the T2{sup *} after running the marathon (30.47 ± 5.16 ms versus 29.84 ± 4.97 ms, P < 0.05) while the T2{sup *} values before the marathon and those after the period of convalescence were similar (29.84 ± 4.97 ms versus 29.81 ± 5.17 ms, P = 0.855). Regional analyses revealed lower T2{sup *} values in the medial tibial plateau (P < 0.001). Conclusions: It appears that repetitive joint loading has a transient influence on the T2{sup *} values. However, this effect is small and probably not clinically relevant. The low T2

  2. An Improved Multivariate T2 Control Chart for Individual Observations in Low Volume Manufacturing

    Institute of Scientific and Technical Information of China (English)

    Miao Rui(苗瑞); Wang Dongpeng; Yao Yingxue

    2004-01-01

    For multivariate statistical process quality control with individual observations, the usually recommended procedure is Hotelling's T2 control chart. Using the T2 statistic based on β distribution is an exact method for constructing multivariate control limits in low volume manufacturing, but it is not convenient in that the variation of sample size leads to a change in control limit. This paper presents an improved multivariate T2 control chart whose control limit does not change with sample size, which is especially useful when the sample size is small.

  3. High signals in the uterine cervix on T2-weighted MRI sequences

    Energy Technology Data Exchange (ETDEWEB)

    Graef, De M.; Karam, R.; Daclin, P.Y.; Rouanet, J.P. [Department of Radiology, C.M.C. Beausoleil, 119 avenue de Lodeve, 34000 Montpellier (France); Juhan, V. [Department of Radiology, C.H.U. Timone, 13000 Marseille (France); Maubon, A.J. [Department of Radiology, C.H.U. Dupuytren, 87000 Limoges (France)

    2003-01-01

    The aim of this pictorial review was to illustrate the normal cervix appearance on T2-weighted images, and give a review of common or less common disorders of the uterine cervix that appear as high signal intensity lesions on T2-weighted sequences. Numerous aetiologies dominated by cervical cancer are reviewed and discussed. This gamut is obviously incomplete; however, radiologists who perform MR women's imaging should perform T2-weighted sequences in the sagittal plane regardless of the indication for pelvic MR. Those sequences will diagnose some previously unknown cervical cancers as well as many other unknown cervical or uterine lesions. (orig.)

  4. A faster, high precision algorithm for calculating symmetric and asymmetric $M_{T2}$

    CERN Document Server

    Lally, Colin H

    2015-01-01

    A new algorithm for calculating the stransverse mass, $M_{T2}$, in either symmetric or asymmetric situations has been developed which exhibits good stability, high precision and quadratic convergence for the majority of the $M_{T2}$ parameter space, leading to up to a factor of ten increase in speed compared to other $M_{T2}$ calculators of comparable precision. This document describes and validates the methodology used by the algorithm, and provides comparisons both in terms of accuracy and speed with other existing implementations.

  5. Automatic Mapping Extraction from Multiecho T2-Star Weighted Magnetic Resonance Images for Improving Morphological Evaluations in Human Brain

    Directory of Open Access Journals (Sweden)

    Shaode Yu

    2013-01-01

    Full Text Available Mapping extraction is useful in medical image analysis. Similarity coefficient mapping (SCM replaced signal response to time course in tissue similarity mapping with signal response to TE changes in multiecho T2-star weighted magnetic resonance imaging without contrast agent. Since different tissues are with different sensitivities to reference signals, a new algorithm is proposed by adding a sensitivity index to SCM. It generates two mappings. One measures relative signal strength (SSM and the other depicts fluctuation magnitude (FMM. Meanwhile, the new method is adaptive to generate a proper reference signal by maximizing the sum of contrast index (CI from SSM and FMM without manual delineation. Based on four groups of images from multiecho T2-star weighted magnetic resonance imaging, the capacity of SSM and FMM in enhancing image contrast and morphological evaluation is validated. Average contrast improvement index (CII of SSM is 1.57, 1.38, 1.34, and 1.41. Average CII of FMM is 2.42, 2.30, 2.24, and 2.35. Visual analysis of regions of interest demonstrates that SSM and FMM show better morphological structures than original images, T2-star mapping and SCM. These extracted mappings can be further applied in information fusion, signal investigation, and tissue segmentation.

  6. Measurement of the intrinsic electron neutrino component in the T2K neutrino beam with the ND280 detector

    Science.gov (United States)

    Abe, K.; Adam, J.; Aihara, H.; Akiri, T.; Andreopoulos, C.; Aoki, S.; Ariga, A.; Ariga, T.; Assylbekov, S.; Autiero, D.; Barbi, M.; Barker, G. J.; Barr, G.; Bass, M.; Batkiewicz, M.; Bay, F.; Bentham, S. W.; Berardi, V.; Berger, B. E.; Berkman, S.; Bertram, I.; Bhadra, S.; Blaszczyk, F. d. M.; Blondel, A.; Bojechko, C.; Bordoni, S.; Boyd, S. B.; Brailsford, D.; Bravar, A.; Bronner, C.; Buchanan, N.; Calland, R. G.; Caravaca Rodríguez, J.; Cartwright, S. L.; Castillo, R.; Catanesi, M. G.; Cervera, A.; Cherdack, D.; Christodoulou, G.; Clifton, A.; Coleman, J.; Coleman, S. J.; Collazuol, G.; Connolly, K.; Cremonesi, L.; Dabrowska, A.; Danko, I.; Das, R.; Davis, S.; de Perio, P.; De Rosa, G.; Dealtry, T.; Dennis, S. R.; Densham, C.; Di Lodovico, F.; Di Luise, S.; Drapier, O.; Duboyski, T.; Duffy, K.; Dufour, F.; Dumarchez, J.; Dytman, S.; Dziewiecki, M.; Emery, S.; Ereditato, A.; Escudero, L.; Finch, A. J.; Floetotto, L.; Friend, M.; Fujii, Y.; Fukuda, Y.; Furmanski, A. P.; Galymov, V.; Giffin, S.; Giganti, C.; Gilje, K.; Goeldi, D.; Golan, T.; Gomez-Cadenas, J. J.; Gonin, M.; Grant, N.; Gudin, D.; Hadley, D. R.; Haesler, A.; Haigh, M. D.; Hamilton, P.; Hansen, D.; Hara, T.; Hartz, M.; Hasegawa, T.; Hastings, N. C.; Hayato, Y.; Hearty, C.; Helmer, R. L.; Hierholzer, M.; Hignight, J.; Hillairet, A.; Himmel, A.; Hiraki, T.; Hirota, S.; Holeczek, J.; Horikawa, S.; Huang, K.; Ichikawa, A. K.; Ieki, K.; Ieva, M.; Ikeda, M.; Imber, J.; Insler, J.; Irvine, T. J.; Ishida, T.; Ishii, T.; Ives, S. J.; Iwai, E.; Iyogi, K.; Izmaylov, A.; Jacob, A.; Jamieson, B.; Johnson, R. A.; Jo, J. H.; Jonsson, P.; Jung, C. K.; Kabirnezhad, M.; Kaboth, A. C.; Kajita, T.; Kakuno, H.; Kameda, J.; Kanazawa, Y.; Karlen, D.; Karpikov, I.; Kearns, E.; Khabibullin, M.; Khotjantsev, A.; Kielczewska, D.; Kikawa, T.; Kilinski, A.; Kim, J.; Kisiel, J.; Kitching, P.; Kobayashi, T.; Koch, L.; Kolaceke, A.; Konaka, A.; Kormos, L. L.; Korzenev, A.; Koseki, K.; Koshio, Y.; Kreslo, I.; Kropp, W.; Kubo, H.; Kudenko, Y.; Kumaratunga, S.; Kurjata, R.; Kutter, T.; Lagoda, J.; Laihem, K.; Lamont, I.; Larkin, E.; Laveder, M.; Lawe, M.; Lazos, M.; Lee, K. P.; Lindner, T.; Lister, C.; Litchfield, R. P.; Longhin, A.; Ludovici, L.; Macaire, M.; Magaletti, L.; Mahn, K.; Malek, M.; Manly, S.; Marino, A. D.; Marteau, J.; Martin, J. F.; Maruyama, T.; Marzec, J.; Mathie, E. L.; Matveev, V.; Mavrokoridis, K.; Mazzucato, E.; McCarthy, M.; McCauley, N.; McFarland, K. S.; McGrew, C.; Metelko, C.; Mezzetto, M.; Mijakowski, P.; Miller, C. A.; Minamino, A.; Mineev, O.; Mine, S.; Missert, A.; Miura, M.; Monfregola, L.; Moriyama, S.; Mueller, Th. A.; Murakami, A.; Murdoch, M.; Murphy, S.; Myslik, J.; Nagasaki, T.; Nakadaira, T.; Nakahata, M.; Nakai, T.; Nakamura, K.; Nakayama, S.; Nakaya, T.; Nakayoshi, K.; Naples, D.; Nielsen, C.; Nirkko, M.; Nishikawa, K.; Nishimura, Y.; O'Keeffe, H. M.; Ohta, R.; Okumura, K.; Okusawa, T.; Oryszczak, W.; Oser, S. M.; Owen, R. A.; Oyama, Y.; Palladino, V.; Palomino, J.; Paolone, V.; Payne, D.; Perevozchikov, O.; Perkin, J. D.; Petrov, Y.; Pickard, L.; Pinzon Guerra, E. S.; Pistillo, C.; Plonski, P.; Poplawska, E.; Popov, B.; Posiadala, M.; Poutissou, J.-M.; Poutissou, R.; Przewlocki, P.; Quilain, B.; Radicioni, E.; Ratoff, P. N.; Ravonel, M.; Rayner, M. A. M.; Redij, A.; Reeves, M.; Reinherz-Aronis, E.; Retiere, F.; Robert, A.; Rodrigues, P. A.; Rojas, P.; Rondio, E.; Roth, S.; Rubbia, A.; Ruterbories, D.; Sacco, R.; Sakashita, K.; Sánchez, F.; Sato, F.; Scantamburlo, E.; Scholberg, K.; Schoppmann, S.; Schwehr, J.; Scott, M.; Seiya, Y.; Sekiguchi, T.; Sekiya, H.; Sgalaberna, D.; Shiozawa, M.; Short, S.; Shustrov, Y.; Sinclair, P.; Smith, B.; Smith, R. J.; Smy, M.; Sobczyk, J. T.; Sobel, H.; Sorel, M.; Southwell, L.; Stamoulis, P.; Steinmann, J.; Still, B.; Suda, Y.; Suzuki, A.; Suzuki, K.; Suzuki, S. Y.; Suzuki, Y.; Szeglowski, T.; Tacik, R.; Tada, M.; Takahashi, S.; Takeda, A.; Takeuchi, Y.; Tanaka, H. K.; Tanaka, H. A.; Tanaka, M. M.; Terhorst, D.; Terri, R.; Thompson, L. F.; Thorley, A.; Tobayama, S.; Toki, W.; Tomura, T.; Totsuka, Y.; Touramanis, C.; Tsukamoto, T.; Tzanov, M.; Uchida, Y.; Ueno, K.; Vacheret, A.; Vagins, M.; Vasseur, G.; Wachala, T.; Waldron, A. V.; Walter, C. W.; Wark, D.; Wascko, M. O.; Weber, A.; Wendell, R.; Wilkes, R. J.; Wilking, M. J.; Wilkinson, C.; Williamson, Z.; Wilson, J. R.; Wilson, R. J.; Wongjirad, T.; Yamada, Y.; Yamamoto, K.; Yanagisawa, C.; Yen, S.; Yershov, N.; Yokoyama, M.; Yuan, T.; Yu, M.; Zalewska, A.; Zalipska, J.; Zambelli, L.; Zaremba, K.; Ziembicki, M.; Zimmerman, E. D.; Zito, M.; Żmuda, J.; T2K Collaboration

    2014-05-01

    The T2K experiment has reported the first observation of the appearance of electron neutrinos in a muon neutrino beam. The main and irreducible background to the appearance signal comes from the presence in the neutrino beam of a small intrinsic component of electron neutrinos originating from muon and kaon decays. In T2K, this component is expected to represent 1.2% of the total neutrino flux. A measurement of this component using the near detector (ND280), located 280 m from the target, is presented. The charged current interactions of electron neutrinos are selected by combining the particle identification capabilities of both the time projection chambers and electromagnetic calorimeters of ND280. The measured ratio between the observed electron neutrino beam component and the prediction is 1.01±0.10 providing a direct confirmation of the neutrino fluxes and neutrino cross section modeling used for T2K neutrino oscillation analyses. Electron neutrinos coming from muons and kaons decay are also separately measured, resulting in a ratio with respect to the prediction of 0.68±0.30 and 1.10±0.14, respectively.

  7. Correlation of T1 and T2 relaxation rates in normal bone-marrow water with serum ferritin concentration

    Energy Technology Data Exchange (ETDEWEB)

    Ishizaka, H. [Tano General Hospital, Gunma (Japan). Dept. of Radiology]|[Gunma Univ. Hospital (Japan). Dept. of Diagnostic Radiology; Ishijima, H. [Gunma Univ. Hospital (Japan). Dept. of Diagnostic Radiology

    1997-11-01

    Purpose: This study was made to clarify the paramagnetic effect of iron stored in the hematopoietic tissue of bone marrow. Material and methods: The T1 and T2 relaxation times of bone-marrow water in the L1-3 vertebrae of 20 healthy individuals were measured by MR imaging with a 1.5 T magnet. The chemical shift misregistration effect was used to isolate the bone-marrow water. The results were compared with the serum ferritin concentration. Results and Conclusion: Although no correlation between the T1 relaxation rate of the water fraction and the serum ferritin concentration was evident, the T2 relaxation rate of the water fraction showed strong linear correlation with the serum ferritin concentration (r=0.87, p<0.001). Thus, T2 of bone-marrow water accurately reflects the amount of iron in normal bone marrow. This finding may be useful in the evaluation of the characteristics of hematopoietic tissue in bone marrow. (orig.).

  8. Europium-engineered iron oxide nanocubes with high T1 and T2 contrast abilities for MRI in living subjects.

    Science.gov (United States)

    Yang, Lijiao; Zhou, Zijian; Liu, Hanyu; Wu, Changqiang; Zhang, Hui; Huang, Guoming; Ai, Hua; Gao, Jinhao

    2015-04-21

    Magnetic resonance imaging (MRI) contrast agents with both positive (T1) and negative (T2) contrast abilities are needed in clinical diagnosis for fault-free accurate detection of lesions. We report a facile synthesis of europium-engineered iron oxide (EuIO) nanocubes as T1 and T2 contrast agents for MRI in living subjects. The Eu(iii) oxide-embedded iron oxide nanoparticles significantly increase the T1 relaxivity with an enhanced positive contrast effect. EuIO nanocubes with 14 nm in diameter showed a high r1 value of 36.8 mM(-1) s(-1) with respect to total metal ions (Fe + Eu), which is about 3 times higher than that of Fe3O4 nanoparticles with similar size. Moreover, both r1 and r2 values of EuIO nanocubes can be tuned by varying their sizes and Eu doping ratios. After citrate coating, EuIO nanocubes can provide enhanced T1 and T2 contrast effects in small animals, particularly in the cardiac and liver regions. This work may provide an insightful strategy to design MRI contrast agents with both positive and negative contrast abilities for biomedical applications.

  9. Measurement of the intrinsic electron neutrino component in the T2K neutrino beam with the ND280 detector

    CERN Document Server

    Abe, K; Aihara, H; Akiri, T; Andreopoulos, C; Aoki, S; Ariga, A; Ariga, T; Assylbekov, S; Autiero, D; Barbi, M; Barker, G J; Barr, G; Bass, M; Batkiewicz, M; Bay, F; Bentham, S W; Berardi, V; Berger, B E; Berkman, S; Bertram, I; Bhadra, S; Blaszczyk, F d M; Blondel, A; Bojechko, C; Bordoni, S; Boyd, S B; Brailsford, D; Bravar, A; Bronner, C; Buchanan, N; Calland, R G; Rodríguez, J Caravaca; Cartwright, S L; Castillo, R; Catanesi, M G; Cervera, A; Cherdack, D; Christodoulou, G; Clifton, A; Coleman, J; Coleman, S J; Collazuol, G; Connolly, K; Cremonesi, L; Dabrowska, A; Danko, I; Das, R; Davis, S; de Perio, P; De Rosa, G; Dealtry, T; Dennis, S R; Densham, C; Di Lodovico, F; Di Luise, S; Drapier, O; Duboyski, T; Duffy, K; Dufour, F; Dumarchez, J; Dytman, S; Dziewiecki, M; Emery, S; Ereditato, A; Escudero, L; Finch, A J; Floetotto, L; Friend, M; Fujii, Y; Fukuda, Y; Furmanski, A P; Galymov, V; Giffin, S; Giganti, C; Gilje, K; Goeldi, D; Golan, T; Gomez-Cadenas, J J; Gonin, M; Grant, N; Gudin, D; Hadley, D R; Haesler, A; Haigh, M D; Hamilton, P; Hansen, D; Hara, T; Hartz, M; Hasegawa, T; Hastings, N C; Hayato, Y; Hearty, C; Helmer, R L; Hierholzer, M; Hignight, J; Hillairet, A; Himmel, A; Hiraki, T; Hirota, S; Holeczek, J; Horikawa, S; Huang, K; Ichikawa, A K; Ieki, K; Ieva, M; Ikeda, M; Imber, J; Insler, J; Irvine, T J; Ishida, T; Ishii, T; Ives, S J; Iwai, E; Iyogi, K; Izmaylov, A; Jacob, A; Jamieson, B; Johnson, R A; Jo, J H; Jonsson, P; Jung, C K; Kabirnezhad, M; Kaboth, A C; Kajita, T; Kakuno, H; Kameda, J; Kanazawa, Y; Karlen, D; Karpikov, I; Kearns, E; Khabibullin, M; Khotjantsev, A; Kielczewska, D; Kikawa, T; Kilinski, A; Kim, J; Kisiel, J; Kitching, P; Kobayashi, T; Koch, L; Kolaceke, A; Konaka, A; Kormos, L L; Korzenev, A; Koseki, K; Koshio, Y; Kreslo, I; Kropp, W; Kubo, H; Kudenko, Y; Kumaratunga, S; Kurjata, R; Kutter, T; Lagoda, J; Laihem, K; Lamont, I; Laveder, M; Lawe, M; Lazos, M; Lee, K P; Lindner, T; Lister, C; Litchfield, R P; Longhin, A; Ludovici, L; Macaire, M; Magaletti, L; Mahn, K; Malek, M; Manly, S; Marino, A D; Marteau, J; Martin, J F; Maruyama, T; Marzec, J; Mathie, E L; Matveev, V; Mavrokoridis, K; Mazzucato, E; McCarthy, M; McCauley, N; McFarland, K S; McGrew, C; Metelko, C; Mezzetto, M; Mijakowski, P; Miller, C A; Minamino, A; Mineev, O; Mine, S; Missert, A; Miura, M; Monfregola, L; Moriyama, S; Mueller, Th A; Murakami, A; Murdoch, M; Murphy, S; Myslik, J; Nagasaki, T; Nakadaira, T; Nakahata, M; Nakai, T; Nakamura, K; Nakayama, S; Nakaya, T; Nakayoshi, K; Naples, D; Nielsen, C; Nirkko, M; Nishikawa, K; Nishimura, Y; O'Keeffe, H M; Ohta, R; Okumura, K; Okusawa, T; Oryszczak, W; Oser, S M; Owen, R A; Oyama, Y; Palladino, V; Paolone, V; Payne, D; Perevozchikov, O; Perkin, J D; Petrov, Y; Pickard, L; Guerra, E S Pinzon; Pistillo, C; Plonski, P; Poplawska, E; Popov, B; Posiadala, M; Poutissou, J M; Poutissou, R; Przewlocki, P; Quilain, B; Radicioni, E; Ratoff, P N; Ravonel, M; Rayner, M A M; Redij, A; Reeves, M; Reinherz-Aronis, E; Retiere, F; Robert, A; Rodrigues, P A; Rojas, P; Rondio, E; Roth, S; Rubbia, A; Ruterbories, D; Sacco, R; Sakashita, K; Sánchez, F; Sato, F; Scantamburlo, E; Scholberg, K; Schoppmann, S; Schwehr, J; Scott, M; Seiya, Y; Sekiguchi, T; Sekiya, H; Sgalaberna, D; Shiozawa, M; Short, S; Shustrov, Y; Sinclair, P; Smith, B; Smith, R J; Smy, M; Sobczyk, J T; Sobel, H; Sorel, M; Southwell, L; Stamoulis, P; Steinmann, J; Still, B; Suda, Y; Suzuki, A; Suzuki, K; Suzuki, S Y; Suzuki, Y; Szeglowski, T; Tacik, R; Tada, M; Takahashi, S; Takeda, A; Takeuchi, Y; Tanaka, H K; Tanaka, H A; Tanaka, M M; Terhorst, D; Terri, R; Thompson, L F; Thorley, A; Tobayama, S; Toki, W; Tomura, T; Totsuka, Y; Touramanis, C; Tsukamoto, T; Tzanov, M; Uchida, Y; Ueno, K; Vacheret, A; Vagins, M; Vasseur, G; Wachala, T; Waldron, A V; Walter, C W; Wark, D; Wascko, M O; Weber, A; Wendell, R; Wilkes, R J; Wilking, M J; Wilkinson, C; Williamson, Z; Wilson, J R; Wilson, R J; Wongjirad, T; Yamada, Y; Yamamoto, K; Yanagisawa, C; Yen, S; Yershov, N; Yokoyama, M; Yuan, T; Yu, M; Zalewska, A; Zalipska, J; Zambelli, L; Zaremba, K; Ziembicki, M; Zimmerman, E D; Zito, M; Zmuda, J

    2014-01-01

    The T2K experiment has reported the first observation of the appearance of electron neutrinos in a muon neutrino beam. The main and irreducible background to the appearance signal comes from the presence in the neutrino beam of a small intrinsic component of electron neutrinos originating from muon and kaon decays. In T2K, this component is expected to represent 1.2% of the total neutrino flux. A measurement of this component using the near detector (ND280), located 280 m from the target, is presented. The charged current interactions of electron neutrinos are selected by combining the particle identification capabilities of both the time projection chambers and electromagnetic calorimeters of ND280. The measured ratio between the observed electron neutrino beam component and the prediction is 1.01+-0.10 providing a direct confirmation of the neutrino fluxes and neutrino cross section modeling used for T2K neutrino oscillation analyses. Electron neutrinos coming from muons and kaons decay are also separately ...

  10. Detecting Acute Myocardial Infarction by Diffusion-Weighted versus T2-Weighted Imaging and Myocardial Necrosis Markers.

    Science.gov (United States)

    Jin, Jiyang; Chen, Min; Li, Yongjun; Wang, YaLing; Zhang, Shijun; Wang, Zhen; Wang, Lin; Ju, Shenghong

    2016-10-01

    We used a porcine model of acute myocardial infarction to study the signal evolution of ischemic myocardium on diffusion-weighted magnetic resonance images (DWI). Eight Chinese miniature pigs underwent percutaneous left anterior descending or left circumflex coronary artery occlusion for 90 minutes followed by reperfusion, which induced acute myocardial infarction. We used DWI preprocedurally and hourly for 4 hours postprocedurally. We acquired turbo inversion recovery magnitude T2-weighted images (TIRM T2WI) and late gadolinium enhancement images from the DWI slices. We measured the serum myocardial necrosis markers myoglobin, creatine kinase-MB isoenzyme, and cardiac troponin I at the same time points as the magnetic resonance scanning. We used histochemical staining to confirm injury. All images were analyzed qualitatively. Contrast-to-noise ratio (the contrast between infarcted and healthy myocardium) and relative signal index were used in quantitative image analysis. We found that DWI identified myocardial signal abnormity early (acute myocardial infarction and identified the infarct-related high signal more often than did TIRM T2WI: 7 of 8 pigs (87.5%) versus 3 of 8 (37.5%) (P=0.046). Quantitative image analysis yielded a significant difference in contrast-to-noise ratio and relative signal index between infarcted and normal myocardium on DWI. However, within 4 hours after infarction, the serologic myocardial injury markers were not significantly positive. We conclude that DWI can be used to detect myocardial signal abnormalities early after acute myocardial infarction-identifying the infarction earlier than TIRM T2WI and widely used clinical serologic biomarkers.

  11. Phase Locked Photon Echoes for Extended Storage Time

    CERN Document Server

    Ham, B S

    2009-01-01

    We report a quantum optical storage time-extended near perfect photon echo protocol using a phase locking method via an auxiliary spin state, where the phase locking acts as a conditional stopper of the rephasing process resulting in extension of storage time determined by the spin dephasing process. The near perfect retrieval efficiency is owing to phase conjugate scheme, which gives the important benefit of aberration corrections when dealing with quantum images.

  12. Occipital seizures and subcortical T2 hypointensity in the setting of hyperglycemia

    Directory of Open Access Journals (Sweden)

    Swapna L. Putta

    2014-01-01

    Conclusion: Hyperglycemia should be considered in the etiology of differential diagnosis of patients with visual abnormalities suspicious for seizures, especially when the MRI shows focal subcortical T2 hypointensity with or without leptomeningeal enhancement.

  13. [Alfred Ritscher. Reval an der schwelle zur neuzeit. T. 2] / Paul Kaegbein

    Index Scriptorium Estoniae

    Kaegbein, Paul

    2006-01-01

    Arvustus: Ritscher, Alfred. Reval an der schwelle zur neuzeit. T. 2: Vom tode Wolters von Plettenberg bis zum Untergang des Deutschen Ordens in Livland (1535-1561). Bonn: Kulturstiftung der deutshen Vertriebenen 2001. (Historische Forschungen).

  14. [Alfred Ritscher. Reval an der schwelle zur neuzeit. T. 2] / Paul Kaegbein

    Index Scriptorium Estoniae

    Kaegbein, Paul

    2006-01-01

    Arvustus: Ritscher, Alfred. Reval an der schwelle zur neuzeit. T. 2: Vom tode Wolters von Plettenberg bis zum Untergang des Deutschen Ordens in Livland (1535-1561). Bonn: Kulturstiftung der deutshen Vertriebenen 2001. (Historische Forschungen).

  15. 物联网自治安全适配层模型以及T2ToI中T2T匿名认证协议%Autonomous Security Adaptive Layer for IOT and T2T Anonymous Authentication Protocols in T2ToI

    Institute of Scientific and Technical Information of China (English)

    任伟; 宋军; 叶敏; 刘宇靓

    2011-01-01

    System model and network model of IOT are presented. Security requirements for IOT are also analyzed. An autonomous security layer is proposed. A new security problem, anonymous T2T authentication in T2ToI, is pointed out. Several anonymous authentication protocols are proposed.%归纳分析了物联网的系统模型和网络模型、物联网的安全需求,提出了针对物联网的自治安全适配层模型,指出了物联网中一个新安全问题:在T2ToI中的物体间的匿名T2T认证问题,并给出相应匿名认证协议.

  16. 7 tesla T2*-weighted MRI as a tool to improve detection of focal cortical dysplasia.

    Science.gov (United States)

    Veersema, Tim J; van Eijsden, Pieter; Gosselaar, Peter H; Hendrikse, Jeroen; Zwanenburg, Jaco J M; Spliet, Wim G M; Aronica, Eleonora; Braun, Kees P J; Ferrier, Cyrille H

    2016-09-01

    Focal cortical dysplasia is one of the most common underlying pathologies in patients who undergo surgery for refractory epilepsy. Absence of a MRI-visible lesion necessitates additional diagnostic tests and is a predictor of poor surgical outcome. We describe a series of six patients with refractory epilepsy due to histopathologically-confirmed focal cortical dysplasia, for whom pre-surgical 7 tesla T2*-weighted MRI was acquired. In four of six patients, T2* sequences showed areas of marked superficial hypointensity, co-localizing with the epileptogenic lesion. 7 tesla T2* hypointensities overlying focal cortical dysplasia may represent leptomeningeal venous vascular abnormalities associated with the underlying dysplastic cortex. Adding T2* sequences to the MRI protocol may aid in the detection of focal cortical dysplasias.

  17. High-resolution 3D T2-weighted fast spin echo: new applications in the orbit

    Energy Technology Data Exchange (ETDEWEB)

    Simon, Erin M. [Department of Radiology, University of California San Francisco, San Francisco, CA (United States); Department of Radiology, Children' s Hospital of Philadelphia, 34th Street and Civic Center Boulevard, Philadelphia, PA 19104-4399 (United States); McCaffery, Sharon; O' Brien, Joan M. [Department of Ophthalmology, University of California San Francisco, San Francisco, CA (United States); Rowley, Howard A. [Department of Radiology, University of California San Francisco, San Francisco, CA (United States); University of Wisconsin Medical School, Madison, WI (United States); Fischbein, Nancy J. [Department of Radiology, University of California San Francisco, San Francisco, CA (United States); Shimikawa, Ann [General Electric Medical Systems, Milwaukee, WI (United States)

    2003-07-01

    Recent developments have made available for ophthalmologic MR imaging a very high-resolution 3D fast spin echo T2 (3D FSE T2) sequence, which runs in a standard head coil. A modification of this technique, 3D FSEz T2, uses a zero-filled slice interpolation method during post-processing to further improve spatial resolution. We describe the technique and share our early clinical observations in patients with ocular masses. Briefly, the additional information from the 3D FSEz T2 resulted in a change in diagnosis from the conventional imaging series in 11 of (41%) 27 studies, usually through the identification of previously treated retinoblastoma lesions. The new sequence significantly increased diagnostic confidence in six (38%) of the remaining 16 cases, usually through better anatomical detail and lesion conspicuity, and did not change interpretation in 10 cases. Such an approach improves diagnostic confidence and may eliminate the need for a dedicated surface coil examination. (orig.)

  18. Pion emission from the T2K replica target: method, results and application

    CERN Document Server

    Abgrall, N; Anticic, T; Antoniou, N; Argyriades, J; Baatar, B; Blondel, A; Blumer, J; Bogomilov, M; Bravar, A; Brooks, W; Brzychczyk, J; Bubak, A; Bunyatov, S A; Busygina, O; Christakoglou, P; Chung, P; Czopowicz, T; Davis, N; Debieux, S; Di Luise, S; Dominik, W; Dumarchez, J; Dynowski, K; Engel, R; Ereditato, A; Esposito, L S; Feofilov, G A; Fodor, Z; Ferrero, A; Fulop, A; Gazdzicki, M; Golubeva, M; Grabez, B; Grebieszkow, K; Grzeszczuk, A; Guber, F; Haesler, A; Hakobyan, H; Hasegawa, T; Idczak, R; Igolkin, S; Ivanov, Y; Ivashkin, A; Kadija, K; Kapoyannis, A; Katrynska, N; Kielczewska, D; Kikola, D; Kirejczyk, M; Kisiel, J; Kiss, T; Kleinfelder, S; Kobayashi, T; Kochebina, O; Kolesnikov, V I; Kolev, D; Kondratiev, V P; Korzenev, A; Kowalski, S; Krasnoperov, A; Kuleshov, S; Kurepin, A; Lacey, R; Larsen, D; Laszlo, A; Lyubushkin, V V; Mackowiak-Pawlowska, M; Majka, Z; Maksiak, B; Malakhov, A I; Maletic, D; Marchionni, A; Marcinek, A; Maris, I; Marin, V; Marton, K; Matulewicz, T; Matveev, V; Melkumov, G L; Messina, M; Mrowczynski, St; Murphy, S; Nakadaira, T; Nishikawa, K; Palczewski, T; Palla, G; Panagiotou, A D; Paul, T; Peryt, W; Petukhov, O; Planeta, R; Pluta, J; Popov, B A; Posiadala, M; Pulawski, S; Puzovic, J; Rauch, W; Ravonel, M; Renfordt, R; Robert, A; Rohrich, D; Rondio, E; Rossi, B; Roth, M; Rubbia, A; Rustamov, A; Rybczynski, M; Sadovsky, A; Sakashita, K; Savic, M; Sekiguchi, T; Seyboth, P; Shibata, M; Sipos, M; Skrzypczak, E; Slodkowski, M; Staszel, P; Stefanek, G; Stepaniak, J; Strabel, C; Strobele, H; Susa, T; Szuba, M; Tada, M; Taranenko, A; Tereshchenko, V; Tolyhi, T; Tsenov, R; Turko, L; Ulrich, R; Unger, M; Vassiliou, M; Veberic, D; Vechernin, V V; Vesztergombi, G; Wilczek, A; Wlodarczyk, Z; Wojtaszek-Szwarc, A; Wyszynski, O; Zambelli, L; Zipper, W; Hartz, M; Ichikawa, A K; Kubo, H; Marino, A D; Matsuoka, K; Murakami, A; Nakaya, T; Suzuki, K; Yuan, T; Zimmerman, E D

    2013-01-01

    The T2K long-baseline neutrino oscillation experiment in Japan needs precise predictions of the initial neutrino flux. The highest precision can be reached based on detailed measurements of hadron emission from the same target as used by T2K exposed to a proton beam of the same kinetic energy of 30 GeV. The corresponding data were recorded in 2007-2010 by the NA61/SHINE experiment at the CERN SPS using a replica of the T2K graphite target. In this paper details of the experiment, data taking, data analysis method and results from the 2007 pilot run are presented. Furthermore, the application of the NA61/SHINE measurements to the predictions of the T2K initial neutrino flux is described and discussed.

  19. "Venous congestion" as a cause of subcortical white matter T2 hypointensity on magnetic resonance images

    Directory of Open Access Journals (Sweden)

    Jayaprakash Harsha Kamble

    2016-01-01

    Full Text Available Subcortical T2 hypointensity is an uncommon finding seen in very limited conditions such as multiple sclerosis, Sturge-Weber syndrome, and meningitis. Some of the conditions such as moyamoya disease, severe ischemic-anoxic insults, early cortical ischemia, and infarcts are of "arterial origin." We describe two conditions in which "venous congestion" plays a major role in T2 hypointensity - cerebral venous sinus thrombosis (CVST and dural arteriovenous fistula (dAVF. The third case is a case of meningitis, showing T2 hypointensity as well, and can be explained by the "venous congestion" hypothesis. The same hypothesis can explain few of the other conditions causing subcortical T2 hypointensity.

  20. Investigating the differences between electron and muon neutrino interactions using the T2K near detector

    CERN Document Server

    Lamont, Iain

    2015-01-01

    The T2K neutrino beam consists mostly of muon neutrinos with a 1$\\%$ component of electron neutrinos. In order to maximise the physics potential of T2K and other future neutrino experiments, it is important to understand how these electron and muon neutrinos interact. To this end, the ratio of the Charged-Current Quasi-Elastic (CCQE) cross section to the total Charged Current (CC) cross section is taken for both $\

  1. Delay of the Onset of Puberty in Female Rats by Prepubertal Exposure to T-2 Toxin

    Directory of Open Access Journals (Sweden)

    Rong Yang

    2015-11-01

    Full Text Available Growing evidence has revealed the deleterious influence of environmental and food contaminants on puberty onset and development in both animals and children, provoking an increasing health concern. T-2 toxin, a naturally-produced Type A trichothecene mycotoxin which is frequently found in cereal grains and products intended for human and animal consumption, has been shown to impair the reproduction and development in animals. Nevertheless, whether this trichothecene mycotoxin can disturb the onset of puberty in females remains unclear. To clarify this point, infantile female rats were given a daily intragastric administration of vehicle or 187.5 μg/kg body weight of T-2 toxin for five consecutive days from postnatal day 15 to 19, and the effects on puberty onset were evaluated in the present study. The results revealed that the days of vaginal opening, first dioestrus, and first estrus in regular estrous cycle were delayed following prepubertal exposure to T-2 toxin. The relative weights of reproductive organs uterus, ovaries, and vagina, and the incidence of corpora lutea were all diminished in T-2 toxin-treated rats. Serum levels of gonadotropins luteinizing hormone, follicle-stimulating hormone, and estradiol were also reduced by T-2 toxin treatment. The mRNA expressions of hypothalamic gonadotropin-releasing hormone (GnRH and pituitary GnRH receptor displayed significant reductions following exposure to T-2 toxin, which were consistent with the changes of serum gonadotropins, delayed reproductive organ development, and delayed vaginal opening. In conclusion, the present study reveals that prepubertal exposure to T-2 toxin delays the onset of puberty in immature female rats, probably by the mechanism of disturbance of hypothalamic-pituitary-gonadal (HPG axis function. Considering the vulnerability of developmental children to food contaminants and the relative high level of dietary intake of T-2 toxin in children, we think the findings of

  2. Limited redundancy