WorldWideScience

Sample records for double resonance determination

  1. THz/Infrared Double Resonance Two-Photon Spectroscopy of HD+ for Determination of Fundamental Constants

    Directory of Open Access Journals (Sweden)

    Florin Lucian Constantin

    2017-10-01

    Full Text Available A double resonance two-photon spectroscopy scheme is discussed to probe jointly rotational and rovibrational transitions of ensembles of trapped HD+ ions. The two-photon transition rates and lightshifts are calculated with the two-photon tensor operator formalism. The rotational lines may be observed with sub-Doppler linewidth at the hertz level and good signal-to-noise ratio, improving the resolution in HD+ spectroscopy beyond the 10−12 level. The experimental accuracy, estimated at the 10−12 level, is comparable with the accuracy of theoretical calculations of HD+ energy levels. An adjustment of selected rotational and rovibrational HD+ lines may add clues to the proton radius puzzle, may provide an independent determination of the Rydberg constant, and may improve the values of proton-to-electron and deuteron-to-proton mass ratios beyond the 10−11 level.

  2. Double Fano resonances in plasmon coupling nanorods

    International Nuclear Information System (INIS)

    Liu, Fei; Jin, Jie

    2015-01-01

    Fano resonances are investigated in nanorods with symmetric lengths and side-by-side assembly. Single Fano resonance can be obtained by a nanorod dimer, and double Fano resonances are shown in nanorod trimers with side-by-side assembly. With transverse plasmon excitation, Fano resonances are caused by the destructive interference between a bright superradiant mode and dark subradiant modes. The bright mode originates from the electric plasmon resonance, and the dark modes originate from the magnetic resonances induced by near-field inter-rod coupling. Double Fano resonances result from double dark modes at different wavelengths, which are induced and tuned by the asymmetric gaps between the adjacent nanorods. Fano resonances show a high figure of merit and large light extinction in the periodic array of assembled nanorods, which can potentially be used in multiwavelength sensing in the visible and near-infrared regions. (paper)

  3. A novel double-layer molecularly imprinted polymer film based surface plasmon resonance for determination of testosterone in aqueous media

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Yuan; Jing, Lijing; Ding, Yonghong; Wei, Tianxin, E-mail: txwei@bit.edu.cn

    2015-07-01

    Highlights: • The in-situ photo-grafting polymerization method was used to prepare the polymer film. • The synthesized MIF was layer stucture film. • The MIF exhibited good imprinting effect and highly selectivity. - Abstract: This work aimed to prepare a novel double-layer structure molecularly imprinted polymer film (MIF) on the surface plasmon resonance (SPR) sensor chips for detection of testosterone in aqueous media. The film was synthesized by in-situ UV photo polymerization. Firstly, the modification of gold surface of SPR chip was performed by 1-dodecanethiol. Then double-layer MIF was generated on the 1-dodecanethiol modified gold surface. The non-modified and imprinted surfaces were characterized by atomic force microscopy (AFM), fourier transform infrared (FTIR) spectroscopy and contact angle measurements. Analysis of SPR spectroscopy showed that the imprinted sensing film displayed good selectivity for testosterone compared to other analogues and the non-imprinted polymer film (NIF). Within the concentrations range of 1 × 10{sup −12}–1 × 10{sup −8} mol/L, the coupling angle changes of SPR were linear with the negative logarithm of testosterone concentrations (R{sup 2} = 0.993). Based on a signal/noise ratio of three, the detection limit was estimated to be 10{sup −12} mol/L. Finally, the developed MIF was successfully applied to the seawater detection of testosterone. The results in the experiments suggested that a combination of SPR sensing with MIF was a promising alternative method for detection of testosterone in aqueous media.

  4. A novel double-layer molecularly imprinted polymer film based surface plasmon resonance for determination of testosterone in aqueous media

    International Nuclear Information System (INIS)

    Tan, Yuan; Jing, Lijing; Ding, Yonghong; Wei, Tianxin

    2015-01-01

    Highlights: • The in-situ photo-grafting polymerization method was used to prepare the polymer film. • The synthesized MIF was layer stucture film. • The MIF exhibited good imprinting effect and highly selectivity. - Abstract: This work aimed to prepare a novel double-layer structure molecularly imprinted polymer film (MIF) on the surface plasmon resonance (SPR) sensor chips for detection of testosterone in aqueous media. The film was synthesized by in-situ UV photo polymerization. Firstly, the modification of gold surface of SPR chip was performed by 1-dodecanethiol. Then double-layer MIF was generated on the 1-dodecanethiol modified gold surface. The non-modified and imprinted surfaces were characterized by atomic force microscopy (AFM), fourier transform infrared (FTIR) spectroscopy and contact angle measurements. Analysis of SPR spectroscopy showed that the imprinted sensing film displayed good selectivity for testosterone compared to other analogues and the non-imprinted polymer film (NIF). Within the concentrations range of 1 × 10 −12 –1 × 10 −8 mol/L, the coupling angle changes of SPR were linear with the negative logarithm of testosterone concentrations (R 2 = 0.993). Based on a signal/noise ratio of three, the detection limit was estimated to be 10 −12 mol/L. Finally, the developed MIF was successfully applied to the seawater detection of testosterone. The results in the experiments suggested that a combination of SPR sensing with MIF was a promising alternative method for detection of testosterone in aqueous media

  5. Resonant double loop antenna development at ORNL

    International Nuclear Information System (INIS)

    Taylor, D.J.; Baity, F.W.; Brown, R.A.; Bryan, W.E.; Fadnek, A.; Hoffman, D.J.; King, J.F.; Livesey, R.L.; McIlwain, R.L.

    1988-01-01

    As part of the development of ion cyclotron resonant heating (ICRH) systems for fusion research, Oak Ridge National Laboratory (ORNL) has built resonant double loop (RDL) antennas for the Tokamak Fusion Test Reactor (TFTR) (Princeton Plasma Physics Laboratory, Princeton, NJ, US) and Tore Supra (Centre d'Etudes Nucleaire, Cadarache, France). Each antenna has been designed to deliver 4 MW of power. The electrical circuit and the mechanical philosophy employed are the same for both antennas, but different operating environments lead to substantial differences in the designs of specific components. A description and a comparison of the technologies developed in the two designs are presented. 5 refs., 4 figs., 1 tab

  6. Radiofrequency/infrared double resonance spectroscopy of the HD+ ion

    International Nuclear Information System (INIS)

    Carrington, Alan; McNab, I.R.; Montgomerie, C.A.

    1989-01-01

    We describe a double resonance technique for obtaining radiofrequency spectra of the HD + ion in vibration-rotation levels close to the dissociation limit. Infrared transitions are driven by Doppler tuning an HD + ion beam into resonance with a carbon dioxide infrared laser, and are detected by measuring H + fragment ions produced by electric field dissociation of the upper vibration-rotation level. Radiofrequency transitions between nuclear hyperfine components of the lower vibration-rotation level are then detected through resonant increases in the H + fragment ion current. The high spectroscopic resolution obtained, and the ability to measure magnetic dipole hyperfine transitions, will enable the hyperfine constants to be determined accurately. (author)

  7. Understanding the Double Quantum Muonium RF Resonance

    Science.gov (United States)

    Kreitzman, S. R.; Cottrell, S. P.; Fleming, D. G.; Sun-Mack, S.

    A physically intuitive analytical solution to the Mu + RF Hamiltonian and lineshape is developed. The method is based on reformulating the problem in a basis set that explicitly accounts for the 1q RF transitions and identifying an isolated upper 1q quasi-eigenstate within that basis. Subsequently the double quantum resonance explicitly manifests itself via the non-zero interaction term between the pair of lower ortho-normalized 1q basis states, which in this field region are substantially the | \\uparrow \\uparrow > and | \\downarrow \\downarrow > Mu states.

  8. Transmission loss of double wall panels containing Helmholtz resonators

    Science.gov (United States)

    Prydz, R. A.; Kuntz, H. L.; Morrow, D. L.; Wirt, L. S.

    Data and an analysis are presented on the use of Helholtz resonators in double wall panels (i.e., aircraft sidewalls). Several wall materials and resonator configurations were tested, and the resonators were found to substantially increase the transmission loss of the double wall system at the tuning frequency.

  9. Improvement in transmission loss of aircraft double wall with resonators

    Science.gov (United States)

    Sun, Jincai; Shi, Liming; Ye, Xining

    1991-08-01

    A little volume low frequency resonator applicable to double-wall configuration of propeller-driven aircraft was designed on the basis of the principle of Helmholtz resonator. The normal incidence absorption coefficient of the various single resonator has been measured. The agreement between theoretical and experimental results is encouraging. An array of resonators whose resonant frequency at 85 Hz and 160 Hz, respectively, are installed between aircraft double-panel, and it has been shown that transmission loss of the double wall structure with resonators improve 4 dB and 6.5 dB in 1/3rd octave bandwidth at 80 Hz and 160 Hz center frequency, respectively, and 5 dB and 7 dB at resonant frequencies, compared with that of the double wall configuration without resonators.

  10. Resonance enhancement of neutrinoless double electron capture

    International Nuclear Information System (INIS)

    Krivoruchenko, M.I.; Simkovic, Fedor; Frekers, Dieter; Faessler, Amand

    2011-01-01

    The process of neutrinoless double electron (0νECEC) capture is revisited for those cases where the two participating atoms are nearly degenerate in mass. The theoretical framework is the formalism of an oscillation of two atoms with different total lepton number (and parity), one of which can be in an excited state so that mass degeneracy is realized. In such a case and assuming light Majorana neutrinos, the two atoms will be in a mixed configuration with respect to the weak interaction. A resonant enhancement of transitions between such pairs of atoms will occur, which could be detected by the subsequent electromagnetic de-excitation of the excited state of the daughter atom and nucleus. Available data of atomic masses, as well as nuclear and atomic excitations are used to select the most likely candidates for the resonant transitions. Assuming an effective mass for the Majorana neutrino of 1 eV, some half-lives are predicted to be as low as 10 22 years in the unitary limit. It is argued that, in order to obtain more accurate predictions for the 0νECEC half-lives, precision mass measurements of the atoms involved are necessary, which can readily be accomplished by today's high precision Penning traps. Further advancements also require a better understanding of high-lying excited states of the final nuclei (i.e. excitation energy, angular momentum and parity) and the calculation of the nuclear matrix elements.

  11. Magnetophonon resonance in double quantum wells

    Science.gov (United States)

    Ploch, D.; Sheregii, E. M.; Marchewka, M.; Wozny, M.; Tomaka, G.

    2009-05-01

    The experimental results obtained for the magnetotransport in pulsed magnetic fields in the InGaAs/InAlAs double quantum well (DQW) structures of two different shapes of wells and different values of the electron density are reported. The magnetophonon resonance (MPR) was observed for both types of structures within the temperature range 77-125 K. Four kinds of LO phonons are taken into account to interpret the MPR oscillations in the DQW and a method of the Landau level calculation in the DQW is elaborated for this aim. The peculiarity of the MPR in the DQW is the large number of the Landau levels caused by SAS splitting of the electron states (splitting on the symmetric and anti-symmetric states) and the large number of the phonon assistance electron transitions between Landau levels. The significant role of the carrier statistics is shown too. The behavior of the electron states in the DQWs at comparably high temperatures has been studied using the MPR. It is shown that the Huang and Manasreh [Manasreh [Phys. Rev. B 54, 2044 (1996)] model involving screening of exchange interaction is confirmed.

  12. Detection of internal fields in double-metal terahertz resonators

    DEFF Research Database (Denmark)

    Mitrofanov, Oleg; Han, Zhanghua; Ding, Fei

    2017-01-01

    Terahertz (THz) double-metal plasmonic resonators enable enhanced light-matter coupling by exploiting strong field confinement. The double-metal design however restricts access to the internal fields. We propose and demonstrate a method for spatial mapping and spectroscopic analysis of the internal...... electromagnetic fields in double-metal plasmonic resonators. We use the concept of image charges and aperture-type scanning near-field THz time-domain microscopy to probe the fields confined within the closed resonator. The experimental method opens doors to studies of light-matter coupling in deeply sub...

  13. Determination of giant resonance strengths

    International Nuclear Information System (INIS)

    Serr, F.E.

    1983-01-01

    Using theoretical strength functions to describe the different giant resonances expected at excitation energies of the order of (60-85)/Asup(1/3) MeV, we calculate the double differential cross sections d 2 sigma/dΩ dE associated with the reactions 208 Pb(α, α') and 90 Zr(α, α') (Esub(α) = 152 MeV). The angular distributions for the giant quadrupole and giant monopole resonances obtained from fits to these spectra, making simple, commonly used assumptions for the peak shapes and background, are compared to the original angular distributions. The differences between them are an indication of some of the uncertainties affecting the giant resonance strengths extracted from hadron inelastic scattering data. Fits to limited angular regions lead to errors of up to 50% in the value of the energy-weighted sum rule, depending on the angles examined. While it seems possible to extract the correct EWSR for the GMR by carrying out the analyses at 0 0 , no single privileged angle seems to exist in the case of the GQR. (orig.)

  14. Resonant double photoionisation spectroscopy of strontium

    Energy Technology Data Exchange (ETDEWEB)

    Sokell, E; Grimm, M; Sheridan, P, E-mail: emma.sokell@ucd.i, E-mail: paul.sheridan@ucd.i [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland)

    2009-11-01

    Resonant triple-differential cross-section (TDCS) measurements on atomic strontium on the 4p {yields} 4d resonance are presented. All of these TDCS measurements display unexpected lobes at a mutual emission angle for the two electrons of 180{sup o}. Possible explanations for these lobes are explored.

  15. Resonant microsphere gyroscope based on a double Faraday rotator system.

    Science.gov (United States)

    Xie, Chengfeng; Tang, Jun; Cui, Danfeng; Wu, Dajin; Zhang, Chengfei; Li, Chunming; Zhen, Yongqiu; Xue, Chenyang; Liu, Jun

    2016-10-15

    The resonant microsphere gyroscope is proposed based on a double Faraday rotator system for the resonant microsphere gyroscope (RMSG) that is characterized by low insertion losses and does not destroy the reciprocity of the gyroscope system. Use of the echo suppression structure and the orthogonal polarization method can effectively inhibit both the backscattering noise and the polarization error, and reduce them below the system sensitivity limit. The resonance asymmetry rate dropped from 34.2% to 2.9% after optimization of the backscattering noise and the polarization noise, which greatly improved the bias stability and the scale factor linearity of the proposed system. Additionally, based on the optimum parameters for the double Faraday rotator system, a bias stability of 0.04°/s has been established for an integration time of 10 s in 1000 s in a resonator microsphere gyroscope using a microsphere resonator with a diameter of 1 mm and a Q of 7.2×106.

  16. Resonance double magnetic bremsstrahlung in a strong magnetic field

    International Nuclear Information System (INIS)

    Fomin, P.I.; Kholodov, R.I.

    2003-01-01

    The possibility of resonance double magnetic bremsstrahlung in the approximation of weakly excited electron states in a strong external magnetic field is analyzed. The differential probability of this process in the Breit-Wigner form is obtained. The probability of double magnetic bremsstrahlung (second-order process of perturbation theory) is compared with the probability of magnetic bremsstrahlung (first-order process of perturbation theory)

  17. Resonant tunneling through double-barrier structures on graphene

    International Nuclear Information System (INIS)

    Deng Wei-Yin; Zhu Rui; Deng Wen-Ji; Xiao Yun-Chang

    2014-01-01

    Quantum resonant tunneling behaviors of double-barrier structures on graphene are investigated under the tight-binding approximation. The Klein tunneling and resonant tunneling are demonstrated for the quasiparticles with energy close to the Dirac points. The Klein tunneling vanishes by increasing the height of the potential barriers to more than 300 meV. The Dirac transport properties continuously change to the Schrödinger ones. It is found that the peaks of resonant tunneling approximate to the eigen-levels of graphene nanoribbons under appropriate boundary conditions. A comparison between the zigzag- and armchair-edge barriers is given. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  18. Pion double charge exchange in the Δ33 resonance region

    International Nuclear Information System (INIS)

    Wirzba, A.; Toki, H.; Siciliano, E.R.; Johnson, M.B.; Gilman, R.

    1989-01-01

    We examine the model dependence and nuclear-structure sensitivity of several Δ 33 -dominated processes contributing to pion double charge exchange on nuclei in the region of the Δ 33 resonance. These processes include the Δ 33 -nucleon interaction V NΔ and sequential scattering, in which the pion undergoes single charge exchange on two different nucleons. In all cases, the scattering takes place through the exchange of an intermediate π and ρ meson. Sequential-mediated double charge exchange is found to be only moderately sensitive to short-range correlations, meson-nucleon form factors, and the rho meson, whereas V NΔ -mediated double charge exchange is very sensitive to all these effects. Results are given for double charge exchange on 18 O (double isobaric analog transitions) and 16 O (nonanalog transitions). Sequential double charge exchange is shown to favor non-spin-flip matrix elements of the transition operator whereas V NΔ -mediated double charge exchange favors spin-flip matrix elements. The energy dependence of the zero-degree cross sections for V NΔ and sequential scattering are also different: Sequential tends to increase monotonically from 100 to 300 MeV, whereas V NΔ peaks at about 150 MeV. The delta-nucleon interaction is found likely to dominate over sequential scattering in nonanalog double charge exchange. The V NΔ is also large in analog double charge exchange, but it does not enable us to explain the anomalous behavior of the 18 O differential cross sections

  19. Analytical Model of Planar Double Split Ring Resonator

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy; Jensen, Thomas; Krozer, Viktor

    2007-01-01

    This paper focuses on accurate modelling of microstrip double split ring resonators. The impedance matrix representation for coupled lines is applied for the first time to model the SRR, resulting in excellent model accuracy over a wide frequency range. Phase compensation is implemented to take i...

  20. Stimulated resonance Raman spectroscopy: An alternative to laser-rf double resonance for ion spectroscopy

    International Nuclear Information System (INIS)

    Young, L.; Dinneen, T.; Mansour, N.B.

    1988-01-01

    Stimulated resonance Raman spectroscopy is presented as an alternative to laser-rf double resonance for obtaining high-precision measurements in ion beams. By use of a single-phase modulated laser beam to derive the two required fields, the laser--ion-beam alignment is significantly simplified. In addition, this method is especially useful in the low-frequency regime where the laser-rf double-resonance method encounters difficulties due to modifications of the ion-beam velocity distribution. These modifications, which result from interaction with the traveling rf wave used to induce magnetic dipole transitions, are observed and quantitatively modeled

  1. Noble metal nanostructures for double plasmon resonance with tunable properties

    Science.gov (United States)

    Petr, M.; Kylián, O.; Kuzminova, A.; Kratochvíl, J.; Khalakhan, I.; Hanuš, J.; Biederman, H.

    2017-02-01

    We report and compare two vacuum-based strategies to produce Ag/Au materials characterized by double plasmon resonance peaks: magnetron sputtering and method based on the use of gas aggregation sources (GAS) of nanoparticles. It was observed that the double plasmon resonance peaks may be achieved by both of these methods and that the intensities of individual localized surface plasmon resonance peaks may be tuned by deposition conditions. However, in the case of sputter deposition it was necessary to introduce a separation dielectric interlayer in between individual Ag and Au nanoparticle films which was not the case of films prepared by GAS systems. The differences in the optical properties of sputter deposited bimetallic Ag/Au films and coatings consisted of individual Ag and Au nanoparticles produced by GAS is ascribed to the divers mechanisms of nanoparticles formation.

  2. On the role of resonances in double-mode pulsation

    International Nuclear Information System (INIS)

    Dziembowski, W.; Kovacs, G.

    1984-01-01

    Simultaneous effects of resonant coupling and non-linear saturation of linear driving mechanism on the finite amplitude solution of multi-modal pulsation problem and on its stability are investigated. Both effects are calculated in the lowest order of approximation in terms of amplitudes. It is shown that the 2:1 resonance between one of the two linearly unstable modes and a higher frequency mode causes double-mode (fundamental and first overtone) pulsation. In a certain range of parameters, such as the frequency mismatch, the linear growth and damping rates, it is the only stable solution of the problem. (author)

  3. Optically controlled resonant tunneling in a double-barrier diode

    Science.gov (United States)

    Kan, S. C.; Wu, S.; Sanders, S.; Griffel, G.; Yariv, A.

    1991-03-01

    The resonant tunneling effect is optically enhanced in a GaAs/GaAlAs double-barrier structure that has partial lateral current confinement. The peak current increases and the valley current decreases simultaneously when the device surface is illuminated, due to the increased conductivity of the top layer of the structure. The effect of the lateral current confinement on the current-voltage characteristic of a double-barrier resonant tunneling structure was also studied. With increased lateral current confinement, the peak and valley current decrease at a different rate such that the current peak-to-valley ratio increases up to three times. The experimental results are explained by solving the electrostatic potential distribution in the structure using a simple three-layer model.

  4. Resonant Tunneling in Photonic Double Quantum Well Heterostructures

    Directory of Open Access Journals (Sweden)

    Cox Joel

    2010-01-01

    Full Text Available Abstract Here, we study the resonant photonic states of photonic double quantum well (PDQW heterostructures composed of two different photonic crystals. The heterostructure is denoted as B/A/B/A/B, where photonic crystals A and B act as photonic wells and barriers, respectively. The resulting band structure causes photons to become confined within the wells, where they occupy discrete quantized states. We have obtained an expression for the transmission coefficient of the PDQW heterostructure using the transfer matrix method and have found that resonant states exist within the photonic wells. These resonant states occur in split pairs, due to a coupling between degenerate states shared by each of the photonic wells. It is observed that when the resonance energy lies at a bound photonic state and the two photonic quantum wells are far away from each other, resonant states appear in the transmission spectrum of the PDQW as single peaks. However, when the wells are brought closer together, coupling between bound photonic states causes an energy-splitting effect, and the transmitted states each have two peaks. Essentially, this means that the system can be switched between single and double transparent states. We have also observed that the total number of resonant states can be controlled by varying the width of the photonic wells, and the quality factor of transmitted peaks can be drastically improved by increasing the thickness of the outer photonic barriers. It is anticipated that the resonant states described here can be used to develop new types of photonic-switching devices, optical filters, and other optoelectronic devices.

  5. Integral data analysis for resonance parameters determination

    International Nuclear Information System (INIS)

    Larson, N.M.; Leal, L.C.; Derrien, H.

    1997-09-01

    Neutron time-of-flight experiments have long been used to determine resonance parameters. Those resonance parameters have then been used in calculations of integral quantities such as Maxwellian averages or resonance integrals, and results of those calculations in turn have been used as a criterion for acceptability of the resonance analysis. However, the calculations were inadequate because covariances on the parameter values were not included in the calculations. In this report an effort to correct for that deficiency is documented: (1) the R-matrix analysis code SAMMY has been modified to include integral quantities of importance, (2) directly within the resonance parameter analysis, and (3) to determine the best fit to both differential (microscopic) and integral (macroscopic) data simultaneously. This modification was implemented because it is expected to have an impact on the intermediate-energy range that is important for criticality safety applications

  6. Double resonance Raman effects in InN nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Domenech-Amador, N.; Cusco, R.; Artus, L. [Institut Jaume Almera, Consell Superior d' Investigacions Cientifiques (CSIC), Lluis Sole i Sabaris s.n., Barcelona, Catalonia (Spain); Calarco, R. [Institute of Bio- and Nanosystems, Research Center Juelich GmbH, Juelich (Germany); Paul-Drude-Institut fuer Festkoerperelektronik, Berlin (Germany); Yamaguchi, T.; Nanishi, Y. [Faculty of Science and Engineering, Ritsumeikan University, Noji-Higashi, Kusatsu, Shiga 525-8577 (Japan)

    2012-04-15

    We study the excitation wavelength dependence of the Raman spectra of InN nanowires. The E{sub 1}(LO) phonon mode, which is detected in backscattering configuration because of light entering through lateral faces, exhibits an upward frequency shift that can be explained by Martin's double resonance. The E{sub 1} (LO)/E{sub 2}{sup h} intensity ratio increases with the excitation wavelength more rapidly than the A{sub 1}(LO)/E{sub 2}{sup h} ratio measured in InN thin films. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. Frequency Characteristics of Double-Walled Carbon Nanotube Resonator with Different Length

    Directory of Open Access Journals (Sweden)

    Jun-Ha LEE

    2016-05-01

    Full Text Available In this paper, we have conducted classical molecular dynamics simulations for DWCNTs of various wall lengths to investigate their use as ultrahigh frequency nano-mechanical resonators. We sought to determine the variations in the frequency of these resonators according to changes in the DWCNT wall lengths. For a double-walled carbon nanotube resonator with a shorter inner nanotube, the shorter inner nanotube can be considered to be a flexible core, and thus, the length influences the fundamental frequency. In this paper, we analyze the variation in frequency of ultra-high frequency nano-mechnical resonators constructed from DWCNTs with different wall lengths.DOI: http://dx.doi.org/10.5755/j01.ms.22.2.12951

  8. Electron spin resonance (ESR), electron nuclear double resonance (ENDOR) and general triple resonance of irradiated biocarbonates

    International Nuclear Information System (INIS)

    Schramm, D.U.; Rossi, A.M.

    1996-01-01

    Several irradiated bicarbonates were studied by magnetic resonance techniques. Seven paramagnetic species, attributed to CO 2 - , SO 2 - and SO 3 - were identified. Comparison between radiation induced defects in bioaragonites and aragonite single-crystals show that isotropic and orthorhombic CO 2 - centers with broad line spectra are not produced in the latter samples. Vibrational and rotational properties of isotropic CO 2 - centers were studied from low temperature Q-band spectras. Vibrational frequency is determined from the 13 CO 2 - hyperfine spectrum and yielded ν 1.54 x 10 13 s -1 . The correlation time for isotropic CO 2 - , τc) = 1.2 x 10 -11 s (T = 300 K0, is typical of radicals rotating in liquids. ENDOR and General Triple spectroscopy show that orthorhombic CO 2 - centres are surrounded by water molecules located in the second nearest CO 2 2- sites at 5.14, 5.35 and 6.02 A. Water molecules replacing carbonates or as liquid inclusion of growth solution in local crystal imperfections may be responsible for the variety of orthorhombic and isotropic CO 2 - species, respectively. (author)

  9. Polarization Insensitivity in Double-Split Ring and Triple-Split Ring Terahertz Resonators

    International Nuclear Information System (INIS)

    Wu Qian-Nan; Lan Feng; Tang Xiao-Pin; Yang Zi-Qiang

    2015-01-01

    A modified double-split ring resonator and a modified triple-split ring resonator, which offer polarization-insensitive performance, are investigated, designed and fabricated. By displacing the two gaps of the conventional double-split ring resonator away from the center, the second resonant frequency for the 0° polarized wave and the resonant frequency for the 90° polarized wave become increasingly close to each other until they are finally identical. Theoretical and experimental results show that the modified double-split ring resonator and the modified triple-split ring resonator are insensitive to different polarized waves and show strong resonant frequency dips near 433 and 444 GHz, respectively. The results of this work suggest new opportunities for the investigation and design of polarization-dependent terahertz devices based on split ring resonators. (paper)

  10. Vibrational Resonance in an Overdamped System with a Sextic Double-Well Potential

    Institute of Scientific and Technical Information of China (English)

    WANG Can-Jun

    2011-01-01

    The phenomenon of vibrational resonance (VR) in an overdamped system with a sextic double-well potential under the excitation of two different periodic signals is investigated. The approximate analytical expression of the resonance amplitude Q at the low-frequency u is obtained. The VR is observed, and the values of B (the amplitude of the high-frequency signal) and Q (the frequency of the high-frequency signal) at which VR occurs are determined. Moreover, the relationship between B and Q is revealed. The theoretical predictions are found to be in good agreement with the numerical results.%@@ The phenomenon of vibrational resonance(VR)in an overdamped system with a sextic double-well potential under the excitation of two different periodic signals is investigated.The approximate analytical expression of the resonance amplitude Q at the low-frequency ω is obtained.The VR is observed,and the values of B(the amplitude of the high-frequency signal)and Ω(the frequency of the high-frequency signal)at which VR occurs are determined.Moreover,the relationship between B and Ω is revealed.The theoretical predictions are found to be in good agreement with the numerical results.

  11. Resonant tunnel magnetoresistance in a double magnetic tunnel junction

    KAUST Repository

    Useinov, Arthur

    2011-08-09

    We present quasi-classical approach to calculate a spin-dependent current and tunnel magnetoresistance (TMR) in double magnetic tunnel junctions (DMTJ) FML/I/FMW/I/FMR, where the magnetization of the middle ferromagnetic metal layer FMW can be aligned parallel or antiparallel with respect to the fixed magnetizations of the left FML and right FMR ferromagnetic electrodes. The transmission coefficients for components of the spin-dependent current, and TMR are calculated as a function of the applied voltage. As a result, we found a high resonant TMR. Thus, DMTJ can serve as highly effective magnetic nanosensor for biological applications, or as magnetic memory cells by switching the magnetization of the inner ferromagnetic layer FMW.© Springer Science+Business Media, LLC 2011.

  12. 2H{ 19F} REDOR for distance measurements in biological solids using a double resonance spectrometer

    Science.gov (United States)

    Grage, Stephan L.; Watts, Jude A.; Watts, Anthony

    2004-01-01

    A new approach for distance measurements in biological solids employing 2H{ 19F} rotational echo double resonance was developed and validated on 2H, 19F- D-alanine and an imidazopyridine based inhibitor of the gastric H +/K +-ATPase. The 2H- 19F double resonance experiments presented here were performed without 1H decoupling using a double resonance NMR spectrometer. In this way, it was possible to benefit from the relatively longer distance range of fluorine without the need of specialized fluorine equipment. A distance of 2.5 ± 0.3 Å was measured in the alanine derivative, indicating a gauche conformation of the two labels. In the case of the imidazopyridine compound a lower distance limit of 5.2 Å was determined and is in agreement with an extended conformation of the inhibitor. Several REDOR variants were compared, and their advantages and limitations discussed. Composite fluorine dephasing pulses were found to enhance the frequency bandwidth significantly, and to reduce the dependence of the performance of the experiment on the exact choice of the transmitter frequency.

  13. Study of γ-irradiated lithographic polymers by electron spin resonance and electron nuclear double resonance

    International Nuclear Information System (INIS)

    Schlick, S.; Kevan, L.

    1982-01-01

    The room temperature gamma irradiation degradation of the lithographic polymers, poly(methylmethacrylate) (PMMA), poly(methyl-α-chloroacrylate) (PMCA), poly(methyl-α-fluoroacrylate) (PMFA), and poly(methylacrylonitrile) (PMCN), have been studied by electron spin resonance and electron nuclear double resonance (ENDOR) to assess their molecular degradation processes of relevance to electron beam lithography. Two classes of radicals are found, chain radicals and chain scission radicals. PMMA and PMCA mainly form chain scission radicals consistent with degradation while for PMCN the resolution is poorer, and this is only probable. PMFA forms mainly chain radicals consistent with predominant crosslinking. The total radical yield is greatest in PMCA and PMCN. ENDOR is used to assess the compactness of the radiation degradation region for PMMA and PMCA and hence the potential resolution of the resist; this appears to be about the same for these methacrylate polymers

  14. Double resonant excitation of the second harmonic of terahertz raditation in dielectricgraphene layered metamaterials

    DEFF Research Database (Denmark)

    Rapoport, Yu; Grimalsky, V.; Lavrinenko, Andrei

    2017-01-01

    to the interfaces, and generation of the p-type second harmonic wave occurs. The original concept is proposed to employ the double resonance arrangement for the effective generation of the second harmonic. The double resonant case can be realized when a high-permittivity dielectric is at the input of the structure...

  15. Resonant cell of a double nuclear electron resonance spectrometer for performance in a 120-350 Gs magnetic field

    International Nuclear Information System (INIS)

    Baldin, V.I.; Stepanov, A.P.

    1976-01-01

    Spectrometer double-frequency resonance cell construction of a double nuclear electron resonance for operation in 120-350 Gs magnetic fields is described. The cell has been developed from a special decimeter resonator with a concentrated capacitance. The electric and magnetic components of a high frequency field are efficiently divided in the separator. Therefore, the insertion of a measuring coil and a sample in the maximum of the magnetic component of the field does not practically affect the distribution and parameters of the high-frequency field. The double-frequency resonance cell proposed provides for a higher accuracy of measuring amplifications of the nuclear magnetic resonance signals when there is the overhauzer effect for 120-350 Gs magnetic fields

  16. Some double resonance and multiple quantum NMR studies in solids

    Energy Technology Data Exchange (ETDEWEB)

    Wemmer, D.E.

    1978-08-01

    The first section of this work presents the theory and experimental applications to analysis of molecular motion of chemical shielding lineshapes obtained with high resolution double resonance NMR techniques. Analysis of /sup 13/C powder lineshapes in hexamethylbenzene (HMB) and decamethylferrocene (DMFe) show that these molecules reorient in a jumping manner about the symmetry axis. Analysis of proton chemical shielding lineshapes of residual protons in heavy ice (D/sub 2/O) show that protons are exchanged among the tetrahedral positions of neighboring oxygen atoms, consistent with motion expected from defect migration. The second section describes the application of Fourier Transform Double Quantum NMR to measurement of chemical shielding of deuterium in powder samples. Studies of partially deuterated benzene and ferrocene give equal shielding anisotropies, ..delta..sigma = -6.5 ppM. Theoretical predictions and experimental measurements of dipolar couplings between deuterons using FTDQ NMR are presented. Crystals of BaClO/sub 3/.D/sub 2/O, ..cap alpha..,..beta.. d-2 HMB and ..cap alpha..,..beta..,..gamma.. d-3 HMB were studied, as were powders of d-2 HMB and anisic acid. The third section discusses general multiple quantum spectroscopy in dipolar coupled spin systems. Theoretical description is made for creation and detection of coherences between states without quantum number selection rules ..delta..m = +-1. Descriptions of techniques for partial selectivity of order in preparation and detection of multiple quantum coherences are made. The effects on selectivity and resolution of echo pulses during multiple quantum experiments are discussed. Experimental observation of coherences up to order 6 have been made in a sample of benzene dissolved in a liquid crystal. Experimental verifications of order selection and echo generation have been made.

  17. Some double resonance and multiple quantum NMR studies in solids

    International Nuclear Information System (INIS)

    Wemmer, D.E.

    1978-08-01

    The first section of this work presents the theory and experimental applications to analysis of molecular motion of chemical shielding lineshapes obtained with high resolution double resonance NMR techniques. Analysis of 13 C powder lineshapes in hexamethylbenzene (HMB) and decamethylferrocene (DMFe) show that these molecules reorient in a jumping manner about the symmetry axis. Analysis of proton chemical shielding lineshapes of residual protons in heavy ice (D 2 O) show that protons are exchanged among the tetrahedral positions of neighboring oxygen atoms, consistent with motion expected from defect migration. The second section describes the application of Fourier Transform Double Quantum NMR to measurement of chemical shielding of deuterium in powder samples. Studies of partially deuterated benzene and ferrocene give equal shielding anisotropies, Δsigma = -6.5 ppM. Theoretical predictions and experimental measurements of dipolar couplings between deuterons using FTDQ NMR are presented. Crystals of BaClO 3 .D 2 O, α,β d-2 HMB and α,β,γ d-3 HMB were studied, as were powders of d-2 HMB and anisic acid. The third section discusses general multiple quantum spectroscopy in dipolar coupled spin systems. Theoretical description is made for creation and detection of coherences between states without quantum number selection rules Δm = +-1. Descriptions of techniques for partial selectivity of order in preparation and detection of multiple quantum coherences are made. The effects on selectivity and resolution of echo pulses during multiple quantum experiments are discussed. Experimental observation of coherences up to order 6 have been made in a sample of benzene dissolved in a liquid crystal. Experimental verifications of order selection and echo generation have been made

  18. Electromagnetic properties of inner double walled carbon nanotubes investigated by nuclear magnetic resonance

    KAUST Repository

    Bouhrara, M.; Abou-Hamad, E.; Alabedi, G.; Al-Taie, I.; Kim, Y.; Wagberg, T.; Goze-Bac, C.

    2013-01-01

    The nuclear magnetic resonance (NMR) analytical technique was used to investigate the double walled carbon nanotubes (DWNTs) electromagnetic properties of inner walls. The local magnetic and electronic properties of inner nanotubes in DWNTs were analyzed using 25% 13C enriched C 60 by which the effect of dipolar coupling could be minimized. The diamagnetic shielding was determined due to the ring currents on outer nanotubes in DWNTs. The NMR chemical shift anisotropy (CSA) spectra and spin-lattice relaxation studies reveal the metallic properties of the inner nanotubes with a signature of the spin-gap opening below 70 K.

  19. Plasmon resonance in single- and double-layer CVD graphene nanoribbons

    DEFF Research Database (Denmark)

    Wang, Di; Emani, Naresh K.; Chung, Ting Fung

    2015-01-01

    Dynamic tunability of the plasmonic resonance in graphene nanoribbons is desirable in the near-infrared. We demonstrated a constant blue shift of plasmonic resonances in double-layer graphene nanoribbons with respect to single-layer graphene nanoribbons. © OSA 2015.......Dynamic tunability of the plasmonic resonance in graphene nanoribbons is desirable in the near-infrared. We demonstrated a constant blue shift of plasmonic resonances in double-layer graphene nanoribbons with respect to single-layer graphene nanoribbons. © OSA 2015....

  20. Sensing performance analysis on Fano resonance of metallic double-baffle contained MDM waveguide coupled ring resonator

    Science.gov (United States)

    Chen, Ying; Luo, Pei; Liu, Xiaofei; Di, Yuanjian; Han, Shuaitao; Cui, Xingning; He, Lei

    2018-05-01

    Based on the transmission property and the photon localization characteristic of the surface plasmonic sub-wavelength structure, a metallic double-baffle contained metal-dielectric-metal (MDM) waveguide coupled ring resonator is proposed. Like the electromagnetically induced transparency (EIT), the Fano resonance can be achieved by the interference between the metallic double-baffle resonator and the ring resonator. Based on the coupled mode theory, the transmission property is analyzed. Through the numerical simulation by the finite element method (FEM), the quantitative analysis on the influences of the radius R of the ring and the coupling distance g between the metallic double-baffle resonator and the ring resonator for the figure of merit (FOM) is performed. And after the structure parameter optimization, the sensing performance of the waveguide structure is discussed. The simulation results show that the FOM value of the optimized structure can attain to 5.74 ×104 and the sensitivity of resonance wavelength with refractive index drift is about 825 nm/RIU. The range of the detected refractive index is suitable for all gases. The waveguide structure can provide effective theoretical references for the design of integrated plasmonic devices.

  1. Switchable coupling for superconducting qubits using double resonance in the presence of crosstalk

    International Nuclear Information System (INIS)

    Ashhab, S.; Nori, Franco

    2007-01-01

    Several methods have been proposed recently to achieve switchable coupling between superconducting qubits. We discuss some of the main considerations regarding the feasibility of implementing one of those proposals: The double-resonance method. We analyze mainly issues related to the achievable effective coupling strength and the effects of crosstalk on this coupling mechanism. We also find a crosstalk-assisted coupling channel that can be an attractive alternative when implementing the double-resonance coupling proposal

  2. Monte Carlo-narrow resonance calculational techniques for treating double-heterogeneity effects

    International Nuclear Information System (INIS)

    Gelbard, E.M.; Chen, I.J.

    1986-01-01

    Reliable methods already exist for computing resonance integrals (RI's) in regular lattices. But lattice structures always contain irregularities. Such effects have been called ''double-heterogeneity'' effects. Two methods for computing double heterogeneity effects on RI's are reviewed and evaluated. 2 refs., 1 tab

  3. Panel Resonance Control and Cavity Control in Double-Panel Structures for Active Noise Reduction

    NARCIS (Netherlands)

    Ho, J.; Berkhoff, Arthur P.

    2011-01-01

    An analytical and experimental investigation of panel resonance control and cavity control in a double-panel structure is presented in this paper. The double-panel structure, which consists of two panels with air in the gap, is widely adopted in many applications such as aerospace due to its low

  4. Analytical model for double split ring resonators with arbitrary ring width

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy; Jensen, Thomas; Krozer, Viktor

    2008-01-01

    For the first time, the analytical model for a double split ring resonator with unequal width rings is developed. The proposed models for the resonators with equal and unequal widths are based on an impedance matrix representation and provide the prediction of performance in a wide frequency range...

  5. Abnormal pulmonary vein drainage in upper right lobe associated with double aortic arch : magnetic resonance angiography

    International Nuclear Information System (INIS)

    Busto, M.; Dolz, J.L.; Capdevilla, A.; Castanon, M.; Mulet, J.

    1997-01-01

    We present the magnetic resonance (MR) and magnetic resonance angiography (MRA) findings in a case of abnormal pulmonary vein drainage from upper right lobe to superior vena cava, associated with double aortic arch, in a six-month-old boy. (Author) 9 refs

  6. Isotopically selective RIMS of rare radionuclides by double-resonance excitation with cw lasers

    International Nuclear Information System (INIS)

    Bushaw, B.A.; Munley, J.T.

    1990-09-01

    Double-resonance, Resonance Ionization Mass Spectroscopy (RIMS) using two single-frequency dye lasers and a CO 2 laser for photoionization has been shown to be both extremely sensitive and highly selective. Measurements on the radioisotope 210 Pb have demonstrated optical selectivity in excess of 10 9 and detection limits of less than 1 femtogram

  7. Development of a Hydrogen Gas Sensor Using a Double Saw Resonator System at Room Temperature

    Directory of Open Access Journals (Sweden)

    Zainab Yunusa

    2015-02-01

    Full Text Available A double SAW resonator system was developed as a novel method for gas sensing applications. The proposed system was investigated for hydrogen sensing. Commercial Surface Acoustic Wave (SAW resonators with resonance frequencies of 433.92 MHz and 433.42 MHz were employed in the double SAW resonator system configuration. The advantages of using this configuration include its ability for remote measurements, and insensitivity to vibrations and other external disturbances. The sensitive layer is composed of functionalized multiwalled carbon nanotubes and polyaniline nanofibers which were deposited on pre-patterned platinum metal electrodes fabricated on a piezoelectric substrate. This was mounted into the DSAWR circuit and connected in parallel. The sensor response was measured as the difference between the resonance frequencies of the SAW resonators, which is a measure of the gas concentration. The sensor showed good response towards hydrogen with a minimum detection limit of 1%.

  8. Role of depth and location of minima of a double-well potential on vibrational resonance

    International Nuclear Information System (INIS)

    Rajasekar, S; Jeyakumari, S; Chinnathambi, V; Sanjuan, M A F

    2010-01-01

    We report our investigation into the role of depth and location of minima of a double-well potential on vibrational resonance in both underdamped and overdamped Duffing oscillators. The systems are driven by both low- and high-frequency periodic forces. We obtain theoretical expressions for the amplitude g of the high-frequency force at which resonances occur. The depth and location of the minima of the potential wells have a distinct effect on vibrational resonance in the underdamped and overdamped cases. In the underdamped system at least one resonance and at most two resonances occur and the number of resonances can be altered by varying the depth and location of the minima of the potential wells. We show that in the overdamped system there is always one and only one resonance, and the value of g at which resonance occurs is independent of the depth of the wells, but varies linearly with the locations of the minima of the wells.

  9. Tunnel-induced Dipolar Resonances in a Double-well Potential.

    Science.gov (United States)

    Schulz, Bruno; Saenz, Alejandro

    2016-11-18

    A system of two dipolar particles that are confined in a double-well potential and interact via a realistic isotropic interaction potential is investigated as a protoype for ultracold atoms with a magnetic dipole moment or ultracold dipolar heteronuclear diatomic molecules in double-well traps or in optical lattices. The resulting energy spectrum is discussed as a function of the dipole-dipole interaction strength. The variation of the strength of the dipole-dipole interaction is found to lead to various resonance phenomena. Among those are the previously discussed inelastic confinement-induced resonances as well as the dipole-induced resonances. It is found that the double-well potential gives rise to a new type of resonances, tunnel-induced dipolar ones. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Resonant tunnel magnetoresistance in a double magnetic tunnel junction

    KAUST Repository

    Useinov, Arthur; Useinov, Niazbeck Kh H; Tagirov, Lenar R.; Kosel, Jü rgen

    2011-01-01

    We present quasi-classical approach to calculate a spin-dependent current and tunnel magnetoresistance (TMR) in double magnetic tunnel junctions (DMTJ) FML/I/FMW/I/FMR, where the magnetization of the middle ferromagnetic metal layer FMW can

  11. Determining properties of baryon resonances in nuclei

    International Nuclear Information System (INIS)

    Johnson, M.B.; Chen, C.M.; Ernst, D.J.; Jiang, M.F.

    1996-01-01

    Meson-nucleus and photon-nucleus interactions are important sources of information about the medium modifications of baryon resonances in nuclei. Indications of how large the medium effects are for resonances above the Δ 33 (1232) are provided by it combined analysis of photonuclear and pion cross sections in the GeV range of energies. Tile existing data indicate a possible 10-20% renormalization of the pion coupling to higher-lying resonances in nuclei

  12. Pure Electric and Pure Magnetic Resonances in Near-Infrared Metal Double-Triangle Metamaterial Arrays

    International Nuclear Information System (INIS)

    Cao Zhi-Shen; Pan Jian; Chen Zhuo; Zhan Peng; Min Nai-Ben; Wang Zhen-Lin

    2011-01-01

    We experimentally and numerically investigate the optical properties of metamaterial arrays composed of double partially-overlapped metallic nanotriangles fabricated by an angle-resolved nanosphere lithography. We demonstrate that each double-triangle can be viewed as an artificial magnetic element analogous to the conventional metal split-ring-resonator. It is shown that under normal-incidence conditions, individual double-triangle can exhibit a strong local magnetic resonance, but the collective response of the metamaterial arrays is purely electric because magnetic resonances of the two double-triangles in a unit cell having opposite openings are out of phase. For oblique incidences the metamaterial arrays are shown to support a pure magnetic response at the same frequency band. Therefore, switchable electric and magnetic resonances are achieved in double-triangle arrays. Moreover, both the electric and magnetic resonances are shown to allow for a tunability over a large spectral range down to near-infrared. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  13. Spectrometer for external detection of magnetic and related double resonance

    International Nuclear Information System (INIS)

    Sagalyn, P.L.; Alexander, M.N.

    1977-01-01

    The patent relates to an improvement in nuclear magnetic resonance spectrometer apparatus. It consists of a spectrometer which utilizes separate materials containing, respectively, sample and detector spin systems as opposed to one in which the sample and detector spins are contained in the same single material

  14. Double-wall carbon nanotubes doped with different Br2 doping levels: a resonance Raman study.

    Science.gov (United States)

    do Nascimento, Gustavo M; Hou, Taige; Kim, Yoong Ahm; Muramatsu, Hiroyuki; Hayashi, Takuya; Endo, Morinobu; Akuzawa, Noboru; Dresselhaus, Mildred S

    2008-12-01

    This report focuses on the effects of different Br2 doping levels on the radial breathing modes of "double-wall carbon nanotube (DWNT) buckypaper". The resonance Raman profile of the Br2 bands are shown for different DWNT configurations with different Br2 doping levels. Near the maximum intensity of the resonance Raman profile, mainly the Br2 molecules adsorbed on the DWNT surface contribute strongly to the observed omega(Br-Br) Raman signal.

  15. Double giant resonances in time-dependent relativistic mean-field theory

    International Nuclear Information System (INIS)

    Ring, P.; Podobnik, B.

    1996-01-01

    Collective vibrations in spherical nuclei are described in the framework of time-dependent relativistic mean-field theory (RMFT). Isoscalar quadrupole and isovector dipole oscillations that correspond to giant resonances are studied, and possible excitations of higher modes are investigated. We find evidence for modes which can be interpreted as double resonances. In a quantized RMFT they correspond to two-phonon states. (orig.)

  16. High Quality Plasmonic Sensors Based on Fano Resonances Created through Cascading Double Asymmetric Cavities

    OpenAIRE

    Zhang, Xiangao; Shao, Mingzhen; Zeng, Xiaoqi

    2016-01-01

    In this paper, a type of compact nanosensor based on a metal-insulator-metal structure is proposed and investigated through cascading double asymmetric cavities, in which their metal cores shift along different axis directions. The cascaded asymmetric structure exhibits high transmission and sharp Fano resonance peaks via strengthening the mutual coupling of the cavities. The research results show that with the increase of the symmetry breaking in the structure, the number of Fano resonances ...

  17. The use of acoustically tuned resonators to improve the sound transmission loss of double panel partitions

    Science.gov (United States)

    Mason, J. M.; Fahy, F. J.

    1986-10-01

    The effectiveness of tuned Helmholtz resonators connected to the partition cavity in double-leaf partitions utilized in situations requiring low weight structures with high transmission loss is investigated as a method of improving sound transmission loss. This is demonstrated by a simple theoretical model and then experimentally verified. Results show that substantial improvements may be obtained at and around the mass-air-mass frequency for a total resonator volume 15 percent of the cavity volume.

  18. Spin-orbit coupling and electric-dipole spin resonance in a nanowire double quantum dot.

    Science.gov (United States)

    Liu, Zhi-Hai; Li, Rui; Hu, Xuedong; You, J Q

    2018-02-02

    We study the electric-dipole transitions for a single electron in a double quantum dot located in a semiconductor nanowire. Enabled by spin-orbit coupling (SOC), electric-dipole spin resonance (EDSR) for such an electron can be generated via two mechanisms: the SOC-induced intradot pseudospin states mixing and the interdot spin-flipped tunneling. The EDSR frequency and strength are determined by these mechanisms together. For both mechanisms the electric-dipole transition rates are strongly dependent on the external magnetic field. Their competition can be revealed by increasing the magnetic field and/or the interdot distance for the double dot. To clarify whether the strong SOC significantly impact the electron state coherence, we also calculate relaxations from excited levels via phonon emission. We show that spin-flip relaxations can be effectively suppressed by the phonon bottleneck effect even at relatively low magnetic fields because of the very large g-factor of strong SOC materials such as InSb.

  19. Wax Point Determinations Using Acoustic Resonance Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Bostick, D.T.; Jubin, R.T.; Schmidt, T.W.

    2001-06-01

    The thermodynamic characterization of the wax point of a given crude is essential in order to maintain flow conditions that prevent plugging of undersea pipelines. This report summarizes the efforts made towards applying an Acoustic Cavity Resonance Spectrometer (ACRS) to the determination of pressures and temperatures at which wax precipitates from crude. Phillips Petroleum Company, Inc., the CRADA participant, supplied the ACRS. The instrumentation was shipped to Dr. Thomas Schmidt of ORNL, the CRADA contractor, in May 2000 after preliminary software development performed under the guidance of Dr. Samuel Colgate and Dr. Evan House of the University of Florida, Gainesville, Fl. Upon receipt it became apparent that a number of modifications still needed to be made before the ACRS could be precisely and safely used for wax point measurements. This report reviews the sequence of alterations made to the ACRS, as well as defines the possible applications of the instrumentation once the modifications have been completed. The purpose of this Cooperative Research and Development Agreement (CRADA) between Phillips Petroleum Company, Inc. (Participant) and Lockheed Martin Energy Research Corporation (Contractor) was the measurement of the formation of solids in crude oils and petroleum products that are commonly transported through pipelines. This information is essential in the proper design, operation and maintenance of the petroleum pipeline system in the United States. Recently, new petroleum discoveries in the Gulf of Mexico have shown that there is a potential for plugging of undersea pipeline because of the precipitation of wax. It is important that the wax points of the expected crude oils be well characterized so that the production facilities for these new wells are capable of properly transporting the expected production. The goal of this work is to perform measurements of solids formation in crude oils and petroleum products supplied by the Participant. It is

  20. Investigation based on nano-electromechanical system double Si3N4 resonant beam pressure sensor.

    Science.gov (United States)

    Yang, Chuan; Guo, Can; Yuan, Xiaowei

    2011-12-01

    This paper presents a type of NEMS (Nano-Electromechanical System) double Si3N4 resonant beams pressure sensor. The mathematical models are established in allusion to the Si3N4 resonant beams and pressure sensitive diaphragm. The distribution state of stress has been analyzed theoretically based on the mathematical model of pressure sensitive diaphragm; from the analysis result, the position of the Si3N4 resonant beams above the pressure sensitive diaphragm was optimized and then the dominance observed after the double resonant beams are adopted is illustrated. From the analysis result, the position of the Si3N4 resonant beams above the pressure sensitive diaphragm is optimized, illustrating advantages in the adoption of double resonant beams. The capability of the optimized sensor was generally analyzed using the ANSYS software of finite element analysis. The range of measured pressure is 0-400 Kpa, the coefficient of linearity correlation is 0.99346, and the sensitivity of the sensor is 498.24 Hz/Kpa, higher than the traditional sensors. Finally the processing techniques of the sensor chip have been designed with sample being successfully processed.

  1. Pulse Double-Resonance EPR Techniques for the Study of Metallobiomolecules.

    Science.gov (United States)

    Cox, Nicholas; Nalepa, Anna; Pandelia, Maria-Eirini; Lubitz, Wolfgang; Savitsky, Anton

    2015-01-01

    Electron paramagnetic resonance (EPR) spectroscopy exploits an intrinsic property of matter, namely the electron spin and its related magnetic moment. This can be oriented in a magnetic field and thus, in the classical limit, acts like a little bar magnet. Its moment will align either parallel or antiparallel to the field, giving rise to different energies (termed Zeeman splitting). Transitions between these two quantized states can be driven by incident microwave frequency radiation, analogous to NMR experiments, where radiofrequency radiation is used. However, the electron Zeeman interaction alone provides only limited information. Instead, much of the usefulness of EPR is derived from the fact that the electron spin also interacts with its local magnetic environment and thus can be used to probe structure via detection of nearby spins, e.g., NMR-active magnetic nuclei and/or other electron spin(s). The latter is exploited in spin labeling techniques, an exciting new area in the development of noncrystallographic protein structure determination. Although these interactions are often smaller than the linewidth of the EPR experiment, sophisticated pulse EPR methods allow their detection. A number of such techniques are well established today and can be broadly described as double-resonance methods, in which the electron spin is used as a reporter. Below we give a brief description of pulse EPR methods, particularly their implementation at higher magnetic fields, and how to best exploit them for studying metallobiomolecules. © 2015 Elsevier Inc. All rights reserved.

  2. Bandgap properties in locally resonant phononic crystal double panel structures with periodically attached spring–mass resonators

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Denghui, E-mail: qdhsd318@163.com; Shi, Zhiyu, E-mail: zyshi@nuaa.edu.cn

    2016-10-07

    Bandgap properties of the locally resonant phononic crystal double panel structure made of a two-dimensional periodic array of a spring–mass resonator surrounded by n springs (n equals to zero at the beginning of the study) connected between the upper and lower plates are investigated in this paper. The finite element method is applied to calculate the band structure, of which the accuracy is confirmed in comparison with the one calculated by the extended plane wave expansion (PWE) method and the transmission spectrum. Numerical results and further analysis demonstrate that two bands corresponding to the antisymmetric vibration mode open a wide band gap but is cut narrower by a band corresponding to the symmetric mode. One of the regulation rules shows that the lowest frequency on the symmetric mode band is proportional to the spring stiffness. Then, a new design idea of adding springs around the resonator in a unit cell (n is not equal to zero now) is proposed in the need of widening the bandwidth and lowering the starting frequency. Results show that the bandwidth of the band gap increases from 50 Hz to nearly 200 Hz. By introducing the quality factor, the regulation rules with the comprehensive consideration of the whole structure quality limitation, the wide band gap and the low starting frequency are also discussed. - Highlights: • The locally resonant double panel structure opens a band gap in the low frequency region. • The band gap is the coupling between the symmetric and antisymmetric vibration modes. • The band structure of the double panel is the evolution of that of the single plate. • By adding springs around the resonator in a unit cell, the bandwidth gets wider. • The band gap can be controlled by tuning the parameters.

  3. Ion cyclotron wave excitation by double resonance coupling

    International Nuclear Information System (INIS)

    Fasoli, A.; Good, T.N.; Paris, P.J.; Skiff, F.; Tran, M.Q.

    1990-07-01

    A modulated high frequency wave is used to remotely excite low frequency oscillations in a linear, strongly magnetized plasma column. An electromagnetic wave is launched as an extraordinary mode across the plasma by an external waveguide in the Upper Hybrid frequency regime f=f UH =f ce =8 GHz, with P≤2 W. By frequency modulating (at f FM =1-60 kHz, with f ci ≅30 kHz) the pump wave, the resonant layer is swept radially across the profile and perpendicularly to the field lines at f=f FM . The resulting radial oscillation of the electron linear and non linear pressure can be considered to act as a source term for the ion wave. A localized virtual antenna is thereby created inside the plasma. Measurements of the ion dielectric response (interferograms and perturbed distribution functions) via laser induced fluorescence identify the two branches (forward, or ion-acoustic-like, and backward, or Bernstein, modes) of the electrostatic dispersion relation in the ion cyclotron frequency range. By changing the modulation bandwidth, and thus the spatial excursion of the oscillating resonant layer, a control on the perpendicular wavelength of the excited mode can be exerted. In particular, the possibility of selective excitation of the ion Bernstein wave is demonstrated experimentally. (author) 38 refs., 13 figs

  4. Acoustic transmission resonance and suppression through double-layer subwavelength hole arrays

    International Nuclear Information System (INIS)

    Liu Zhifeng; Jin Guojun

    2010-01-01

    We present a theoretical study of acoustic waves passing through double-layer subwavelength hole arrays. The acoustic transmission resonance and suppression are observed. There are three mechanisms responsible for the transmission resonance: the excitation of geometrically induced acoustic surface waves, the Fabry-Perot resonance in a hole cavity (I-FP resonance) and the Fabry-Perot resonance between two plates (II-FP resonance). We can differentiate these mechanisms via the dispersion relation of acoustic modes supported by the double-layer structure. It is confirmed that the coupling between two single-layer perforated plates, associated with longitudinal interval and lateral displacement, plays a crucial role in modulating the transmission properties. The strong coupling between two plates can induce the splitting of the transmission peak, while the decoupling between plates leads to the appearance of transmission suppression. By analyzing the criterion derived for transmission suppression, we conclude that it is the destructive interference between the diffracted waves and the direct transmission waves assisted by the I-FP resonance of the first plate that leads to the decoupling between plates and then the transmission suppression.

  5. Spectral relationships between kicked Harper and on-resonance double kicked rotor operators

    DEFF Research Database (Denmark)

    Lawton, Wayne; Mouritzen, Anders Sørrig; Wang, Jiao

    2009-01-01

    Kicked Harper operators and on-resonance double kicked rotor operators model quantum systems whose semiclassical limits exhibit chaotic dynamics. Recent computational studies indicate a striking resemblance between the spectra of these operators. In this paper we apply C*-algebra methods to expla...

  6. Double-spin-flip resonance of rhodium nuclei at positive and negative spin temperatures

    DEFF Research Database (Denmark)

    Tuoriniemi, J.T.; Knuuttila, T.A.; Lefmann, K.

    2000-01-01

    Sensitive SQUID-NMR measurements were used to study the mutual interactions in the highly polarized nuclear-spin system of rhodium metal. The dipolar coupling gives rise to a weak double-spin-flip resonance. The observed frequency shifts allow deducing separately the dipolarlike contribution...

  7. Double resonance modulation characteristics of optically injection-locked Fabry–Perot lasers

    International Nuclear Information System (INIS)

    Dorogush, E S; Afonenko, A A

    2015-01-01

    The distributed resonator model is used to show the presence of several resonance responses on the modulation characteristic of optically injection-locked Fabry–Perot lasers. The positions of the resonance peaks on the modulation characteristic are determined by the resonator length and frequency detuning of optical injection. It is shown that an appropriate choice of the resonator length and injection locking conditions allows one to obtain efficient modulation in two ranges near 40 – 60 GHz or to increase the direct modulation bandwidth up to 50 GHz. (control of laser radiation parameters)

  8. Double resonance modulation characteristics of optically injection-locked Fabry–Perot lasers

    Energy Technology Data Exchange (ETDEWEB)

    Dorogush, E S; Afonenko, A A [Belarusian State University, Minsk (Belarus)

    2015-12-31

    The distributed resonator model is used to show the presence of several resonance responses on the modulation characteristic of optically injection-locked Fabry–Perot lasers. The positions of the resonance peaks on the modulation characteristic are determined by the resonator length and frequency detuning of optical injection. It is shown that an appropriate choice of the resonator length and injection locking conditions allows one to obtain efficient modulation in two ranges near 40 – 60 GHz or to increase the direct modulation bandwidth up to 50 GHz. (control of laser radiation parameters)

  9. Magnetic resonance of beta-active nuclei at double Larmor frequency in LiF polycrystals with dislocations

    International Nuclear Information System (INIS)

    Bulgakov, M.I.; Dzheparov, F.S.; Gul'ko, A.D.; Shestopal, V.E.; Stepanov, S.V.; Trostin, S.S.

    1989-01-01

    β-NMR-spectroscopy investigations of the resonance at double Larmor frequency of β-active nuclei 8 Li in LiF polycrystals are presented. The qualitative analysis of the dislocation influence on this resonance is developed. An important role of correlations in dislocation distributions as well as high responsivity of this resonance to quadrupole interactions are found. 13 refs.; 2 figs

  10. Modelling the nonlinear behaviour of double walled carbon nanotube based resonator with curvature factors

    Science.gov (United States)

    Patel, Ajay M.; Joshi, Anand Y.

    2016-10-01

    This paper deals with the nonlinear vibration analysis of a double walled carbon nanotube based mass sensor with curvature factor or waviness, which is doubly clamped at a source and a drain. Nonlinear vibrational behaviour of a double-walled carbon nanotube excited harmonically near its primary resonance is considered. The double walled carbon nanotube is harmonically excited by the addition of an excitation force. The modelling involves stretching of the mid plane and damping as per phenomenon. The equation of motion involves four nonlinear terms for inner and outer tubes of DWCNT due to the curved geometry and the stretching of the central plane due to the boundary conditions. The vibrational behaviour of the double walled carbon nanotube with different surface deviations along its axis is analyzed in the context of the time response, Poincaré maps and Fast Fourier Transformation diagrams. The appearance of instability and chaos in the dynamic response is observed as the curvature factor on double walled carbon nanotube is changed. The phenomenon of Periodic doubling and intermittency are observed as the pathway to chaos. The regions of periodic, sub-harmonic and chaotic behaviour are clearly seen to be dependent on added mass and the curvature factors in the double walled carbon nanotube. Poincaré maps and frequency spectra are used to explicate and to demonstrate the miscellany of the system behaviour. With the increase in the curvature factor system excitations increases and results in an increase of the vibration amplitude with reduction in excitation frequency.

  11. Transmitted spectral modulation of double-ring resonator using liquid crystals in terahertz range

    Science.gov (United States)

    Sun, Huijuan; Zhou, Qingli; Wang, Xiumin; Li, Chenyu; Wu, Ani; Zhang, Cunlin

    2013-12-01

    Metamaterials with subwavelength structural features show unique electromagnetic responses that are unattainable with natural materials. Recent research on these artificial materials has been pushed forward to the terahertz region because of potential applications in biological fingerprinting, security imaging, remote sensing, and high frequency magnetic and electric resonant devices. Active control of their properties could further facilitate and open up new applications in terms of modulation and switching. Liquid crystals, which have been the subject of research for more than a century, have the unique properties for the development of many other optical components such as light valves, tunable filters and tunable lenses. In this paper, we investigated the transmitted spectral modulation in terahertz range by using liquid crystals (5CB and TEB300) covering on the fabricated double-ring resonators to realize the shift of the resonance frequency. Our obtained results indicate the low frequency resonance shows the obvious blue-shift, while the location of high frequency resonance is nearly unchanged. We believe this phenomenon is related to not only the refractive index of the covering liquid crystals but also the resonant mechanism of both resonances.

  12. Fast response double series resonant high-voltage DC-DC converter

    International Nuclear Information System (INIS)

    Lee, S S; Iqbal, S; Kamarol, M

    2012-01-01

    In this paper, a novel double series resonant high-voltage dc-dc converter with dual-mode pulse frequency modulation (PFM) control scheme is proposed. The proposed topology consists of two series resonant tanks and hence two resonant currents flow in each switching period. Moreover, it consists of two high-voltage transformer with the leakage inductances are absorbed as resonant inductor in the series resonant tanks. The secondary output of both transformers are rectified and mixed before supplying to load. In the resonant mode operation, the series resonant tanks are energized alternately by controlling two Insulated Gate Bipolar Transistor (IGBT) switches with pulse frequency modulation (PFM). This topology operates in discontinuous conduction mode (DCM) with all IGBT switches operating in zero current switching (ZCS) condition and hence no switching loss occurs. To achieve fast rise in output voltage, a dual-mode PFM control during start-up of the converter is proposed. In this operation, the inverter is started at a high switching frequency and as the output voltage reaches 90% of the target value, the switching frequency is reduced to a value which corresponds to the target output voltage. This can effectively reduce the rise time of the output voltage and prevent overshoot. Experimental results collected from a 100-W laboratory prototype are presented to verify the effectiveness of the proposed system.

  13. Transmission line model for coupled rectangular double split‐ring resonators

    DEFF Research Database (Denmark)

    Yan, Lei; Tang, Meng; Krozer, Viktor

    2011-01-01

    In this work, a model based on a coupled transmission line formulation is developed for microstrip rectangular double split‐ring resonators (DSRRs). This model allows using the physical dimensions of the DSRRs as an input avoiding commonly used extraction of equivalent parameters. The model inclu...... simulations of the DSRR structures. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1311–1315, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25988...

  14. Efficient 525 nm laser generation in single or double resonant cavity

    Science.gov (United States)

    Liu, Shilong; Han, Zhenhai; Liu, Shikai; Li, Yinhai; Zhou, Zhiyuan; Shi, Baosen

    2018-03-01

    This paper reports the results of a study into highly efficient sum frequency generation from 792 and 1556 nm wavelength light to 525 nm wavelength light using either a single or double resonant ring cavity based on a periodically poled potassium titanyl phosphate crystal (PPKTP). By optimizing the cavity's parameters, the maximum power achieved for the resultant 525 nm laser was 263 and 373 mW for the single and double resonant cavity, respectively. The corresponding quantum conversion efficiencies were 8 and 77% for converting 1556 nm photons to 525 nm photons with the single and double resonant cavity, respectively. The measured intra-cavity single pass conversion efficiency for both configurations was about 5%. The performances of the sum frequency generation in these two configurations was studied and compared in detail. This work will provide guidelines for optimizing the generation of sum frequency generated laser light for a variety of configurations. The high conversion efficiency achieved in this work will help pave the way for frequency up-conversion of non-classical quantum states, such as the squeezed vacuum and single photon states. The proposed green laser source will be used in our future experiments, which includes a plan to generate two-color entangled photon pairs and achieve the frequency down-conversion of single photons carrying orbital angular momentum.

  15. Effects of resonant magnetic perturbation on the triggering and the evolution of double-tearing mode

    Science.gov (United States)

    Wang, L.; Lin, W. B.; Wang, X. Q.

    2018-02-01

    The effects of resonant magnetic perturbation on the triggering and the evolution of the double-tearing mode are investigated by using nonlinear magnetohydrodynamics simulations in a slab geometry. It is found that the double-tearing mode can be destabilized by boundary magnetic perturbation. Moreover, the mode has three typical development stages before it reaches saturation: the linear stable stage, the linear-growth stage, and the exponential-growth stage. The onset and growth of the double-tearing mode significantly depend on the boundary magnetic perturbations, particularly in the early development stage of the mode. The influences of the magnetic perturbation amplitude on the mode for different separations of the two rational surfaces are also discussed.

  16. Microwave-optical double resonance spectroscopy. Final report, February 1, 1971-October 31, 1980

    International Nuclear Information System (INIS)

    Pratt, D.W.

    1982-01-01

    Optical, zero-field and high-field optical detection of magnetic resonance, electron-nuclear double resonance, level anticrossing and cross relaxation, and electron paramagnetic resonance experiments have been performed on a variety of chemical systems in order to further basic knowledge of the structure, reactivity, and response to radiation of molecules in their ground and/or excited electronic states. Systems investigated include organic molecules oriented in low temperature crystals, simple free radicals, transition metal complexes, rare earth hydrides, and hemeproteins in biological enzymes. Many of these systems are of potential importance in a number of applied areas including hydrocarbon-based fuel systems, solar energy devices, laser-initiated photochemical reactions, and free radical mechanisms in chemical carcinogenesis

  17. Microwave-optical double resonance spectroscopy. Progress report, February 1, 1978--January 31, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Pratt, D.W.

    1978-11-01

    Optical, zero-field and high-field optical detection of magnetic resonance, electron-nuclear double resonance, level anticrossing and cross relaxation, and electron paramagnetic resonance experiments have been performed on a variety of chemical systems in order to further basic knowledge of the structure, reactivity, and response to radiation of molecules in their ground and/or excited electronic states. Systems investigated include organic molecules oriented in low temperature crystals, simple free radicals, transition metal complexes, rare earth hydrides, and hemeproteins in biological enzymes. Aside from their intrinsic interest, many of these systems are of potential importance in a number of applied areas including hydrocarbon-based fuel systems, solar energy devices, laser-initiated photochemical reactions, and free radical mechanisms in chemical carcinogenesis.

  18. Microwave-optical double resonance spectroscopy. Progress report, February 1, 1978--January 31, 1979

    International Nuclear Information System (INIS)

    Pratt, D.W.

    1978-01-01

    Optical, zero-field and high-field optical detection of magnetic resonance, electron-nuclear double resonance, level anticrossing and cross relaxation, and electron paramagnetic resonance experiments have been performed on a variety of chemical systems in order to further basic knowledge of the structure, reactivity, and response to radiation of molecules in their ground and/or excited electronic states. Systems investigated include organic molecules oriented in low temperature crystals, simple free radicals, transition metal complexes, rare earth hydrides, and hemeproteins in biological enzymes. Aside from their intrinsic interest, many of these systems are of potential importance in a number of applied areas including hydrocarbon-based fuel systems, solar energy devices, laser-initiated photochemical reactions, and free radical mechanisms in chemical carcinogenesis

  19. High Quality Plasmonic Sensors Based on Fano Resonances Created through Cascading Double Asymmetric Cavities.

    Science.gov (United States)

    Zhang, Xiangao; Shao, Mingzhen; Zeng, Xiaoqi

    2016-10-18

    In this paper, a type of compact nanosensor based on a metal-insulator-metal structure is proposed and investigated through cascading double asymmetric cavities, in which their metal cores shift along different axis directions. The cascaded asymmetric structure exhibits high transmission and sharp Fano resonance peaks via strengthening the mutual coupling of the cavities. The research results show that with the increase of the symmetry breaking in the structure, the number of Fano resonances increase accordingly. Furthermore, by modulating the geometrical parameters appropriately, Fano resonances with high sensitivities to the changes in refractive index can be realized. A maximum figure of merit (FoM) value of 74.3 is obtained. Considerable applications for this work can be found in bio/chemical sensors with excellent performance and other nanophotonic integrated circuit devices such as optical filters, switches and modulators.

  20. High Quality Plasmonic Sensors Based on Fano Resonances Created through Cascading Double Asymmetric Cavities

    Directory of Open Access Journals (Sweden)

    Xiangao Zhang

    2016-10-01

    Full Text Available In this paper, a type of compact nanosensor based on a metal-insulator-metal structure is proposed and investigated through cascading double asymmetric cavities, in which their metal cores shift along different axis directions. The cascaded asymmetric structure exhibits high transmission and sharp Fano resonance peaks via strengthening the mutual coupling of the cavities. The research results show that with the increase of the symmetry breaking in the structure, the number of Fano resonances increase accordingly. Furthermore, by modulating the geometrical parameters appropriately, Fano resonances with high sensitivities to the changes in refractive index can be realized. A maximum figure of merit (FoM value of 74.3 is obtained. Considerable applications for this work can be found in bio/chemical sensors with excellent performance and other nanophotonic integrated circuit devices such as optical filters, switches and modulators.

  1. Determination of Dimensionless Attenuation Coefficient in Shaped Resonators

    Science.gov (United States)

    Daniels, C.; Steinetz, B.; Finkbeiner, J.; Raman, G.; Li, X.

    2003-01-01

    The value of dimensionless attenuation coefficient is an important factor when numerically predicting high-amplitude acoustic waves in shaped resonators. Both the magnitude of the pressure waveform and the quality factor rely heavily on this dimensionless parameter. Previous authors have stated the values used, but have not completely explained their methods. This work fully describes the methodology used to determine this important parameter. Over a range of frequencies encompassing the fundamental resonance, the pressure waves were experimentally measured at each end of the shaped resonators. At the corresponding dimensionless acceleration, the numerical code modeled the acoustic waveforms generated in the resonator using various dimensionless attenuation coefficients. The dimensionless attenuation coefficient that most closely matched the pressure amplitudes and quality factors of the experimental and numerical results was determined to be the value to be used in subsequent studies.

  2. A theoretical study of resonant tunneling characteristics in triangular double-barrier diodes

    International Nuclear Information System (INIS)

    Wang Hongmei; Xu Huaizhe; Zhang Yafei

    2006-01-01

    Resonant tunneling characteristics of triangular double-barrier diodes have been investigated systematically in this Letter, using Airy function approach to solve time-independent Schroedinger function in triangular double-barrier structures. Originally, the exact analytic expressions of quasi-bound levels and quasi-level lifetime in symmetrical triangular double-barrier structures have been derived within the effective-mass approximation as a function of structure parameters including well width, slope width and barrier height. Based on our derived analytic expressions, numerical results show that quasi-bound levels and quasi-level lifetime vary nearly linearly with the structure parameters except that the second quasi-level lifetime changes parabolically with slope width. Furthermore, according to our improved transmission coefficient of triangular double-barrier structures under external electric field, the current densities of triangular double-barrier diodes with different slope width at 0 K have been calculated numerically. The results show that the N-shaped negative differential resistance behaviors have been observed in current-voltage characteristics and current-voltage characteristics depend on the slope width

  3. Determination of critical breakage conditions for double glazing in fire

    International Nuclear Information System (INIS)

    Wang, Yu; Li, Ke; Su, Yanfei; Lu, Wei; Wang, Qingsong; Sun, Jinhua; He, Linghui; Liew, K.M.

    2017-01-01

    Highlights: • Critical heat fluxes of exposed and ambient panes are 6 kW/m"2 and 25 kW/m"2. • Critical temperature difference of fire side pane is around 60 °C. • The ambient pane survives three times longer due to radiation filter and air gap. • Heat transfer in double glazing is revealed by a heat flux based theoretical model. - Abstract: Double glazing unit normally demonstrates better fire resistance than single glazing, but the knowledge on its thermal behavior and heat transfer mechanism during fire is limited. In this work, nine double glazing units were heated by a 500 × 500 mm"2 pool fire. The incident heat flux, temperature on four surfaces, breakage time and cracking behavior were obtained. The critical breakage conditions for interior and exterior panes were determined through gradually decreasing the glass-burner distance from 750 mm to 450 mm. It is established that in double glazing the pane at ambient side can withstand significantly more time than the pane exposed to fire. The critical temperature difference for interior pane is 60 °C; the critical temperature of exterior pane breakage is much higher due to no frame-covered area. In addition, the heat flux at the time of crack initiation is 6 kW/m"2 for the pane at fire side, while more than 25 kW/m"2 for ambient side pane. To reveal the heat transfer mechanism in glazing-air-glazing, theoretical and numerical investigations are also performed, which agrees well with the experimental results.

  4. Induced Double-Beta Processes in Electron Fluxes as Resonance Reactions in Weak Interaction

    International Nuclear Information System (INIS)

    Gaponov, Yu.V.

    2004-01-01

    A theory of induced double-beta processes in electron beams is developed. It is shown that a resonance mechanism of the excitation of the ground state of an intermediate nucleus is realized in them, this mechanism being described in the single-state-dominance approximation, where the process in question is broken down into two stages, the excitation of a dominant state and its decay. This approximation is valid irrespective of the features of this state, both for allowed (for a 1 + state of the intermediate nucleus) and for forbidden transitions. An analysis of the resonance mechanism reveals that its inclusion in double-beta-decay processes requires introducing additional diagrams that describe the gamma decay of virtual intermediate states. The inclusion of such corrections may lead to a decrease in the expected half-life and to a change in the beta spectrum. Effects associated with the interference between the two stages of a double-beta process are estimated, and it is shown that their influence can be significant if the time interval between these stages is less than or on the order of the lifetime of the dominant state

  5. Label-Free, Single Molecule Resonant Cavity Detection: A Double-Blind Experimental Study

    Directory of Open Access Journals (Sweden)

    Maria V. Chistiakova

    2015-03-01

    Full Text Available Optical resonant cavity sensors are gaining increasing interest as a potential diagnostic method for a range of applications, including medical prognostics and environmental monitoring. However, the majority of detection demonstrations to date have involved identifying a “known” analyte, and the more rigorous double-blind experiment, in which the experimenter must identify unknown solutions, has yet to be performed. This scenario is more representative of a real-world situation. Therefore, before these devices can truly transition, it is necessary to demonstrate this level of robustness. By combining a recently developed surface chemistry with integrated silica optical sensors, we have performed a double-blind experiment to identify four unknown solutions. The four unknown solutions represented a subset or complete set of four known solutions; as such, there were 256 possible combinations. Based on the single molecule detection signal, we correctly identified all solutions. In addition, as part of this work, we developed noise reduction algorithms.

  6. Equal intensity double plasmon resonance of bimetallic quasi-nanocomposites based on sandwich geometry

    Energy Technology Data Exchange (ETDEWEB)

    Chakravadhanula, V S K; Elbahri, M; Schuermann, U; Takele, H; Greve, H; Zaporojtchenko, V; Faupel, F [Chair for Multicomponent Materials, Technical Faculty of the CAU Kiel, Kaiserstrasse 2, D-24143 Kiel (Germany)], E-mail: ff@tf.uni-kiel.de

    2008-06-04

    We report a strategy to achieve a material showing equal intensity double plasmon resonance (EIDPR) based on sandwich geometry. We studied the interaction between localized plasmon resonances associated with different metal clusters (Au/Ag) on Teflon AF (TAF) in sandwich geometry. Engineering the EIDPR was done by tailoring the amount of Au/Ag and changing the TAF thickness. The samples were investigated by transmission electron microscopy (TEM) and UV-visible spectroscopy. Interestingly, and in agreement with the dipole-surface interaction, the critical barrier thickness for an optimum EIDPR was observed at 3.3 nm. The results clearly show a plasmon sequence effect and visualize the role of plasmon decay.

  7. Propagation of spiking regularity and double coherence resonance in feedforward networks.

    Science.gov (United States)

    Men, Cong; Wang, Jiang; Qin, Ying-Mei; Deng, Bin; Tsang, Kai-Ming; Chan, Wai-Lok

    2012-03-01

    We investigate the propagation of spiking regularity in noisy feedforward networks (FFNs) based on FitzHugh-Nagumo neuron model systematically. It is found that noise could modulate the transmission of firing rate and spiking regularity. Noise-induced synchronization and synfire-enhanced coherence resonance are also observed when signals propagate in noisy multilayer networks. It is interesting that double coherence resonance (DCR) with the combination of synaptic input correlation and noise intensity is finally attained after the processing layer by layer in FFNs. Furthermore, inhibitory connections also play essential roles in shaping DCR phenomena. Several properties of the neuronal network such as noise intensity, correlation of synaptic inputs, and inhibitory connections can serve as control parameters in modulating both rate coding and the order of temporal coding.

  8. Detection of single electron spin resonance in a double quantum dota)

    Science.gov (United States)

    Koppens, F. H. L.; Buizert, C.; Vink, I. T.; Nowack, K. C.; Meunier, T.; Kouwenhoven, L. P.; Vandersypen, L. M. K.

    2007-04-01

    Spin-dependent transport measurements through a double quantum dot are a valuable tool for detecting both the coherent evolution of the spin state of a single electron, as well as the hybridization of two-electron spin states. In this article, we discuss a model that describes the transport cycle in this regime, including the effects of an oscillating magnetic field (causing electron spin resonance) and the effective nuclear fields on the spin states in the two dots. We numerically calculate the current flow due to the induced spin flips via electron spin resonance, and we study the detector efficiency for a range of parameters. The experimental data are compared with the model and we find a reasonable agreement.

  9. Electron paramagnetic resonance and electron-nuclear double-resonance study of Ti{sup 3+} centres in KTiOPO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Setzler, S D [BAE Systems, Nashua, NH 03061 (United States); Stevens, K T [Northrop Grumman, Space Technology, Synoptics, Charlotte, NC 28273 (United States); Fernelius, N C [Air Force Research Laboratory, Materials and Manufacturing Directorate, AFRL/MLPSO, Wright-Patterson AFB, OH 45433 (United States); Scripsick, M P [Nova Phase, Newton, NJ 07860 (United States); Edwards, G J [Department of Physics, West Virginia University, Morgantown, WV 26506 (United States); Halliburton, L E [Department of Physics, West Virginia University, Morgantown, WV 26506 (United States)

    2003-06-18

    Electron paramagnetic resonance and electron-nuclear double resonance have been used to characterize four Ti{sup 3+} centres in undoped crystals of potassium titanyl phosphate (KTiOPO{sub 4} or KTP). These 3d{sup 1} defects (S = 1/2) are produced by ionizing radiation (either 60 kV x-rays or 355 nm photons from a tripled Nd:YAG laser), and form when the regular Ti{sup 4+} ions in the crystal trap an electron. Two of these trapped-electron centres are only observed in hydrothermally grown KTP and the other two are dominant in flux-grown KTP. Both of the Ti{sup 3+} centres in hydrothermally grown crystals have a neighbouring proton (i.e. an OH{sup -} molecule). In the flux-grown crystals, one of the Ti{sup 3+} centres is adjacent to an oxygen vacancy and the other centre is tentatively attributed to a self-trapped electron (i.e. a Ti{sup 3+} centre with no stabilizing entity nearby). The g matrix and phosphorus hyperfine matrices are determined for all four Ti{sup 3+} centres, and the proton hyperfine matrix is determined for the two centres associated with OH{sup -} ions. These Ti{sup 3+} centres contribute to the formation of the grey tracks often observed in KTP crystals used to generate the second harmonic of high-power, near-infrared lasers.

  10. Double threshold behavior in a resonance-controlled ZnO random laser

    Directory of Open Access Journals (Sweden)

    Ryo Niyuki

    2017-03-01

    Full Text Available We observed unusual lasing characteristics, such as double thresholds and blue-shift of lasing peak, in a resonance-controlled ZnO random laser. From the analysis of lasing threshold carrier density, we found that the lasing at 1st and 2nd thresholds possibly arises from different mechanisms; the lasing at 1st threshold involves exciton recombination, whereas the lasing at 2nd threshold is caused by electron-hole plasma recombination, which is the typical origin of conventional random lasers. These phenomena are very similar to the transition from polariton lasing to photon lasing observed in a well-defined cavity laser.

  11. Dissipative Double-Well Potential for Cold Atoms: Kramers Rate and Stochastic Resonance.

    Science.gov (United States)

    Stroescu, Ion; Hume, David B; Oberthaler, Markus K

    2016-12-09

    We experimentally study particle exchange in a dissipative double-well potential using laser-cooled atoms in a hybrid trap. We measure the particle hopping rate as a function of barrier height, temperature, and atom number. Single-particle resolution allows us to measure rates over more than 4 orders of magnitude and distinguish the effects of loss and hopping. Deviations from the Arrhenius-law scaling at high barrier heights occur due to cold collisions between atoms within a well. By driving the system periodically, we characterize the phenomenon of stochastic resonance in the system response.

  12. Sidewall gated double well quasi-one-dimensional resonant tunneling transistors

    Science.gov (United States)

    Kolagunta, V. R.; Janes, D. B.; Melloch, M. R.; Youtsey, C.

    1997-12-01

    We present gating characteristics of submicron vertical resonant tunneling transistors in double quantum well heterostructures. Current-voltage characteristics at room temperature and 77 K for devices with minimum feature widths of 0.9 and 0.7 μm are presented and discussed. The evolution of the I-V characteristics with increasing negative gate biases is related to the change in the lateral confinement, with a transition from a large area 2D to a quasi-1D. Even gating of multiple wells and lateral confinement effects observable at 77 K make these devices ideally suited for applications in multi-valued logic systems and low-dimensional structures.

  13. Infinite dwell time and group delay in resonant electron tunneling through double complex potential barrier

    Science.gov (United States)

    Opacak, Nikola; Milanović, Vitomir; Radovanović, Jelena

    2017-12-01

    Tunneling times in complex potentials are investigated. Analytical expressions for dwell time, self-interference time and group delay are obtained for the case of complex double delta potentials. It is shown that we can always find a set of parameters of the potential so that the tunneling times achieve very large values and even approach infinity for the case of resonance. The phenomenon of infinite tunneling times occurs for only one particular positive value of the imaginary part of the potential, if all other parameters are given.

  14. Modeling and characterization of double resonant tunneling diodes for application as energy selective contacts in hot carrier solar cells

    Science.gov (United States)

    Jehl, Zacharie; Suchet, Daniel; Julian, Anatole; Bernard, Cyril; Miyashita, Naoya; Gibelli, Francois; Okada, Yoshitaka; Guillemolles, Jean-Francois

    2017-02-01

    Double resonant tunneling barriers are considered for an application as energy selective contacts in hot carrier solar cells. Experimental symmetric and asymmetric double resonant tunneling barriers are realized by molecular beam epitaxy and characterized by temperature dependent current-voltage measurements. The negative differential resistance signal is enhanced for asymmetric heterostructures, and remains unchanged between low- and room-temperatures. Within Tsu-Esaki description of the tunnel current, this observation can be explained by the voltage dependence of the tunnel transmission amplitude, which presents a resonance under finite bias for asymmetric structures. This effect is notably discussed with respect to series resistance. Different parameters related to the electronic transmission of the structure and the influence of these parameters on the current voltage characteristic are investigated, bringing insights on critical processes to optimize in double resonant tunneling barriers applied to hot carrier solar cells.

  15. Rapid vibrational and rotational energy-transfer rates in heated carbon dioxide collisions by double-resonance laser spectroscopy

    International Nuclear Information System (INIS)

    Thomason, M.D.

    1982-07-01

    Rates for resonant vibrational and rotational energy transfer from the 001 state by CO 2 + CO 2 collisions have been measured. All data were obtained by double resonance spectroscopy with CO 2 lasers in a 2.5 meter absorption cell at 700 0 K. Results for rotation transfer include pumped-level relaxation and the response of other 001 levels with ΔJ up to 18. These data are compared to four relevant collision models via a 35-level rate equation analysis. Sequence-band (002 → 101) and hot-band (011 → 110) lasting have been used to observe resonant nu 3 -transfer relaxation involving 001 + 001 reversible 002 + 000, 001 + 100 reversible 101 + 000, and 001 + 010 reversible 011 + 000. A multilevel rate analysis has been utilized to determine the rate coefficients for 001 going to the 002, the 101, and the 011 levels. Part of the hot-band data has been interpreted as due to 110 + 000 reversible 100 + 010, and the associated rate constant has been estimated. The results of the study are compared to the theory and to other experiments

  16. Determination of space-energy distribution of resonance neutrons in reactor lattice cell and calculation of resonance integrals

    International Nuclear Information System (INIS)

    Zmijarevic, I.

    1980-01-01

    Space-energy distribution of resonance neutrons in reactor lattice cell was determined by solving the Boltzmann equation by spherical harmonics method applying P-3 approximation. Computer code SPLET used for these calculations is described. Resonance absorption and calculation of resonance integrals are described as well. Effective resonance integral values for U-238 resonance at 6.7 Ev are calculated for heavy water reactor cell with metal, oxide and carbide fuel elements

  17. Determination of resonance parameters in QCD by functional analysis methods

    International Nuclear Information System (INIS)

    Ciulli, S.; Geniet, F.; Papadopoulos, N.A.; Schilcher, K.

    1988-01-01

    A mathematically rigorous method based on functional analysis is used to determine resonance parameters of an amplitude from its given asymptotic expression in the space-like region. This method is checked on a model amplitude where both the asymptotic expression and the exact function are known. This method is then applied to the determination of the mass and the width of the ρ-meson from the corresponding space-like asymptotic QCD expression. (orig.)

  18. Technique for magnetic susceptibility determination in the highly doped semiconductors by electron spin resonance

    Energy Technology Data Exchange (ETDEWEB)

    Veinger, A. I.; Zabrodskii, A. G.; Tisnek, T. V.; Goloshchapov, S. I.; Semenikhin, P. V. [Ioffe Institute of the Russian Academy of Sciences, St. Petersburg (Russian Federation)

    2014-08-20

    A method for determining the magnetic susceptibility in the highly doped semiconductors is considered. It is suitable for the semiconductors near the metal - insulator transition when the conductivity changes very quickly with the temperature and the resonance line form distorts. A procedure that is based on double integration of the positive part of the derivative of the absorption line having a Dyson shape and takes into account the depth of the skin layer is described. Analysis is made for the example of arsenic-doped germanium samples at a rather high concentration corresponding to the insulator-metal phase transition.

  19. CP violation induced by the double resonance for pure annihilation decay process in perturbative QCD

    Energy Technology Data Exchange (ETDEWEB)

    Lue, Gang; Li, Sheng-Tao; Wang, Yu-Ting [Henan University of Technology, College of Science, Zhengzhou (China); Lu, Ye [Guangxi Normal University, Department of Physics, Guilin (China)

    2017-08-15

    In a perturbative QCD approach we study the direct CP violation in the pure annihilation decay process of anti B{sup 0}{sub s} → π{sup +}π{sup -}π{sup +}π{sup -} induced by the ρ and ω double resonance effect. Generally, the CP violation is small in the pure annihilation type decay process. However, we find that the CP violation can be enhanced by double ρ-ω interference when the invariant masses of the π{sup +}π{sup -} pairs are in the vicinity of the ω resonance. For the decay process of anti B{sup 0}{sub s} → π{sup +}π{sup -}π{sup +}π{sup -}, the CP violation can reach A{sub CP}(anti B{sup 0}{sub s} → π{sup +}π{sup -}π{sup +}π{sup -}) = 27.20{sup +0.05+0.28+7.13}{sub -0.15-0.31-6.11}%. (orig.)

  20. Tunable Resonant-Cavity-Enhanced Photodetector with Double High-Index-Contrast Grating Mirrors

    DEFF Research Database (Denmark)

    Learkthanakhachon, Supannee; Yvind, Kresten; Chung, Il-Sug

    2013-01-01

    In this paper, we propose a broadband-tunable resonant-cavity-enhanced photodetector (RCE-PD) structure with double high-index-contrast grating (HCG) mirrors and numerically investigate its characteristics. The detector is designed to operate at 1550-nm wavelength. The detector structure consists....... Furthermore, the fact that it can be fabricated on a silicon platform offers us a possibility of integration with electronics.......In this paper, we propose a broadband-tunable resonant-cavity-enhanced photodetector (RCE-PD) structure with double high-index-contrast grating (HCG) mirrors and numerically investigate its characteristics. The detector is designed to operate at 1550-nm wavelength. The detector structure consists...... of a top InP HCG mirror, a p-i-n photodiode embedding multiple quantum wells, and a Si HCG mirror formed in the Si layer of a silicon-on-insulator wafer. The detection wavelength can be changed by moving the top InP HCG mirror suspended in the air. High reflectivity and small penetration length of HCGs...

  1. In Vivo Application of Proton-Electron Double-Resonance Imaging

    Science.gov (United States)

    Kishimoto, Shun; Krishna, Murali C.; Khramtsov, Valery V.; Utsumi, Hideo

    2018-01-01

    Abstract Significance: Proton-electron double-resonance imaging (PEDRI) employs electron paramagnetic resonance irradiation with low-field magnetic resonance imaging so that the electron spin polarization is transferred to nearby protons, resulting in higher signals. PEDRI provides information about free radical distribution and, indirectly, about the local microenvironment such as partial pressure of oxygen (pO2), tissue permeability, redox status, and acid-base balance. Recent Advances: Local acid-base balance can be imaged by exploiting the different resonance frequency of radical probes between R and RH+ forms. Redox status can also be imaged by using the loss of radical-related signal after reduction. These methods require optimized radical probes and pulse sequences. Critical Issues: High-power radio frequency irradiation is needed for optimum signal enhancement, which may be harmful to living tissue by unwanted heat deposition. Free radical probes differ depending on the purpose of PEDRI. Some probes are less effective for enhancing signal than others, which can reduce image quality. It is so far not possible to image endogenous radicals by PEDRI because low concentrations and broad line widths of the radicals lead to negligible signal enhancement. Future Directions: PEDRI has similarities with electron paramagnetic resonance imaging (EPRI) because both techniques observe the EPR signal, directly in the case of EPRI and indirectly with PEDRI. PEDRI provides information that is vital to research on homeostasis, development of diseases, or treatment responses in vivo. It is expected that the development of new EPR techniques will give insights into novel PEDRI applications and vice versa. Antioxid. Redox Signal. 28, 1345–1364. PMID:28990406

  2. Electron paramagnetic resonance and electron-nuclear double-resonance study of Ti sup 3 sup + centres in KTiOPO sub 4

    CERN Document Server

    Setzler, S D; Fernelius, N C; Scripsick, M P; Edwards, G J; Halliburton, L E

    2003-01-01

    Electron paramagnetic resonance and electron-nuclear double resonance have been used to characterize four Ti sup 3 sup + centres in undoped crystals of potassium titanyl phosphate (KTiOPO sub 4 or KTP). These 3d sup 1 defects (S = 1/2) are produced by ionizing radiation (either 60 kV x-rays or 355 nm photons from a tripled Nd:YAG laser), and form when the regular Ti sup 4 sup + ions in the crystal trap an electron. Two of these trapped-electron centres are only observed in hydrothermally grown KTP and the other two are dominant in flux-grown KTP. Both of the Ti sup 3 sup + centres in hydrothermally grown crystals have a neighbouring proton (i.e. an OH sup - molecule). In the flux-grown crystals, one of the Ti sup 3 sup + centres is adjacent to an oxygen vacancy and the other centre is tentatively attributed to a self-trapped electron (i.e. a Ti sup 3 sup + centre with no stabilizing entity nearby). The g matrix and phosphorus hyperfine matrices are determined for all four Ti sup 3 sup + centres, and the proto...

  3. Displacement and resonance behaviors of a piezoelectric diaphragm driven by a double-sided spiral electrode

    KAUST Repository

    Shen, Zhiyuan

    2012-04-03

    This paper presents the design of a lead zirconate titanate (PZT) diaphragm actuated by double-sided patterned electrodes. Au/Cr electrodes were deposited on bulk PZT wafers by sputtering while patterned by a lift-off process. SU-8 thick film was used to form the structural layer. Double-spiral electrode induced in-plane poling and piezoelectric elongation are converted to an out-of-plane displacement due to the confined boundary condition. The influence of different drive configurations and electrode parameters on deflection has been calculated by finite element methods (FEM) using a uniform field model. Impedance and quasi-static displacement spectra of the diaphragm were measured after poling. Adouble-sided patterned electrode diaphragm can be actuated by more drive configurations than a single-sided one. Compared with a single-sided electrode drive, a double-sided out-of-phase drive configuration increases the coupling coefficient of the fundamental resonance from 7.6% to 11.8%. The displacement response of the diaphragm increases from 2.6 to 8.6nmV 1. Configurations including the electric field component perpendicular to the poling direction can stimulate shear modes of the diaphragm. © 2012 IOP Publishing Ltd.

  4. Control of the symmetry breaking in double-well potentials by the resonant nonlinearity management

    International Nuclear Information System (INIS)

    Nistazakis, H. E.; Frantzeskakis, D. J.; Malomed, B. A.; Kevrekidis, P. G.

    2011-01-01

    We introduce a one-dimensional model of Bose-Einstein condensates (BECs), combining the double-well potential, which is a usual setting for the onset of spontaneous-symmetry-breaking (SSB) effects, and time-periodic modulation of the nonlinearity, which may be implemented by means of the Feshbach-resonance-management (FRM) technique. Both cases of the nonlinearity that is repulsive or attractive on the average are considered. In the former case, the main effect produced by the application of the FRM is spontaneous self-trapping of the condensate in either of the two potential wells in parameter regimes where it would remain untrapped in the absence of the management. In the weakly nonlinear regime, the frequency of intrinsic oscillations in the FRM-induced trapped state is very close to half the FRM frequency, suggesting that the effect is accounted for by a parametric resonance. In the case of the attractive nonlinearity, the FRM-induced effect is the opposite, i.e., enforced detrapping of a state which is self-trapped in its unmanaged form. In the latter case, the frequency of oscillations of the untrapped mode is close to a quarter of the driving frequency, suggesting that a higher-order parametric resonance may account for this effect.

  5. Determining the helicity structure of third generation resonances

    International Nuclear Information System (INIS)

    Papaefstathiou, Andreas

    2011-11-01

    We examine methods that have been proposed for determining the helicity structure of decays of new resonances to third generation quarks and/or leptons. We present analytical and semi-analytical predictions and assess the applicability of the relevant variables in realistic reconstruction scenarios using Monte Carlo-generated events, including the effects of QCD radiation and multiple parton interactions, combinatoric ambiguities and fast detector simulation. (orig.)

  6. Free radicals imaged in vivo in the rat by using proton-electron double-resonance imaging

    International Nuclear Information System (INIS)

    Lurie, D.J.; Nicholson, Ian; Foster, M.A.; Mallard, J.R.

    1990-01-01

    A new technique called proton-electron double-resonance imaging is described for imaging free radicals in aqueous samples. The method is a combination of proton NMR imaging with nuclear electron double resonance. The results of using this technique to image free radicals in vivo in the rat are presented. Rats were injected intravenously with a nitroxide free radical solution and a series of images was obtained from which the clearance of the free radical through the liver and kidneys could be observed. (author)

  7. Double plasma resonance instability as a source of solar zebra emission

    Science.gov (United States)

    Benáček, J.; Karlický, M.

    2018-03-01

    Context. The double plasma resonance (DPR) instability plays a basic role in the generation of solar radio zebras. In the plasma, consisting of the loss-cone type distribution of hot electrons and much denser and colder background plasma, this instability generates the upper-hybrid waves, which are then transformed into the electromagnetic waves and observed as radio zebras. Aims: In the present paper we numerically study the double plasma resonance instability from the point of view of the zebra interpretation. Methods: We use a 3-dimensional electromagnetic particle-in-cell (3D PIC) relativistic model. We use this model in two versions: (a) a spatially extended "multi-mode" model and (b) a spatially limited "specific-mode" model. While the multi-mode model is used for detailed computations and verifications of the results obtained by the "specific-mode" model, the specific-mode model is used for computations in a broad range of model parameters, which considerably save computational time. For an analysis of the computational results, we developed software tools in Python. Results: First using the multi-mode model, we study details of the double plasma resonance instability. We show how the distribution function of hot electrons changes during this instability. Then we show that there is a very good agreement between results obtained by the multi-mode and specific-mode models, which is caused by a dominance of the wave with the maximal growth rate. Therefore, for computations in a broad range of model parameters, we use the specific-mode model. We compute the maximal growth rates of the double plasma resonance instability with a dependence on the ratio between the upper-hybrid ωUH and electron-cyclotron ωce frequency. We vary temperatures of both the hot and background plasma components and study their effects on the resulting growth rates. The results are compared with the analytical ones. We find a very good agreement between numerical and analytical growth

  8. Electron spin resonance and spin-valley physics in a silicon double quantum dot.

    Science.gov (United States)

    Hao, Xiaojie; Ruskov, Rusko; Xiao, Ming; Tahan, Charles; Jiang, HongWen

    2014-05-14

    Silicon quantum dots are a leading approach for solid-state quantum bits. However, developing this technology is complicated by the multi-valley nature of silicon. Here we observe transport of individual electrons in a silicon CMOS-based double quantum dot under electron spin resonance. An anticrossing of the driven dot energy levels is observed when the Zeeman and valley splittings coincide. A detected anticrossing splitting of 60 MHz is interpreted as a direct measure of spin and valley mixing, facilitated by spin-orbit interaction in the presence of non-ideal interfaces. A lower bound of spin dephasing time of 63 ns is extracted. We also describe a possible experimental evidence of an unconventional spin-valley blockade, despite the assumption of non-ideal interfaces. This understanding of silicon spin-valley physics should enable better control and read-out techniques for the spin qubits in an all CMOS silicon approach.

  9. Resonant tunnel magnetoresistance in double-barrier planar magnetic tunnel junctions

    KAUST Repository

    Useinov, A. N.

    2011-08-24

    We present a theoretical approach to calculate the spin-dependent current and tunnel magnetoresistance (TMR) in a double-barrier magnetic tunnel junction (DMTJ), in which the magnetization of the middle ferromagnetic metal layer can be aligned parallel or antiparallel in relation to the fixed magnetizations of the left and right ferromagnetic electrodes. The electron transport through the DMTJ is considered as a three-dimensional problem, taking into account all transmitting electron trajectories as well as the spin-dependent momentum conservation law. The dependence of the transmission coefficient and spin-polarized currents on the applied voltage is derived as an exact solution to the quantum-mechanical problem for the spin-polarized transport. In the range of the developed physical model, the resonant tunneling, nonresonant tunneling, and enhanced spin filtering can be explained; the simulation results are in good agreement with experimental data.

  10. Resonant tunnel magnetoresistance in double-barrier planar magnetic tunnel junctions

    KAUST Repository

    Useinov, A. N.; Kosel, Jü rgen; Useinov, N. Kh.; Tagirov, L. R.

    2011-01-01

    We present a theoretical approach to calculate the spin-dependent current and tunnel magnetoresistance (TMR) in a double-barrier magnetic tunnel junction (DMTJ), in which the magnetization of the middle ferromagnetic metal layer can be aligned parallel or antiparallel in relation to the fixed magnetizations of the left and right ferromagnetic electrodes. The electron transport through the DMTJ is considered as a three-dimensional problem, taking into account all transmitting electron trajectories as well as the spin-dependent momentum conservation law. The dependence of the transmission coefficient and spin-polarized currents on the applied voltage is derived as an exact solution to the quantum-mechanical problem for the spin-polarized transport. In the range of the developed physical model, the resonant tunneling, nonresonant tunneling, and enhanced spin filtering can be explained; the simulation results are in good agreement with experimental data.

  11. Conformational Structure of Tyrosine, Tyrosyl-Glycine, and Tyrosyl-Glycyl-Glycine by Double Resonance Spectroscopy

    Science.gov (United States)

    Abo-Riziq, Ali; Grace, Louis; Crews, Bridgit; Callahan, Michael P,; van Mourik, Tanja; de Vries, Mattanjah S,

    2011-01-01

    We investigated the variation in conformation for the amino acid tyrosine (Y), alone and in the small peptides tyrosine-glycine (YC) and tyrosine-glycine-glycine (YGG), in the gas phase by using UV-UV and IR-UV double resonance spectroscopy and density functional theory calculations. For tyrosine we found seven different conformations, for YG we found four different conformations, and for YGG we found three different conformations. As the peptides get larger, we observe fewer stable conformers, despite the increasing complexity and number of degrees of freedom. We find structural trends similar to those in phenylalanine-glycine glycine (FGG) and tryptophan-glycine-glycine (WGG)j however) the effect of dispersive forces in FGG for stabilizing a folded structure is replaced by that of hydrogen bonding in YGG.

  12. A metamaterial terahertz modulator based on complementary planar double-split-ring resonator

    Science.gov (United States)

    Wang, Chang-hui; Kuang, Deng-feng; Chang, Sheng-jiang; Lin, Lie

    2013-07-01

    A metamaterial based on complementary planar double-split-ring resonator (DSRR) structure is presented and demonstrated, which can optically tune the transmission of the terahertz (THz) wave. Unlike the traditional DSRR metamaterials, the DSRR discussed in this paper consists of two split rings connected by two bridges. Numerical simulations with the finite-difference time-domain (FDTD) method reveal that the transmission spectra of the original and the complementary metamaterials are both in good agreement with Babinet's principle. Then by increasing the carrier density of the intrinsic GaAs substrate, the magnetic response of the complementary special DSRR metamaterial can be weakened or even turned off. This metamaterial structure is promised to be a narrow-band THz modulator with response time of several nanoseconds.

  13. Resonance spiking by periodic loss in the double-sided liquid cooling disk oscillator

    Science.gov (United States)

    Nie, Rongzhi; She, Jiangbo; Li, Dongdong; Li, Fuli; Peng, Bo

    2017-03-01

    A double-sided liquid cooling Nd:YAG disk oscillator working at a pump repetition rate of 20 Hz is demonstrated. The output energy of 376 mJ is realized, corresponding to the optical-optical efficiency of 12.8% and the slope efficiency of 14%. The pump pulse width is 300 µs and the laser pulse width is 260 µs. Instead of being a damped signal, the output of laser comprises undamped spikes. A periodic intra-cavity loss was found by numerical analysis, which has a frequency component near the eigen frequency of the relaxation oscillation. Resonance effect will induce amplified spikes even though the loss fluctuates in a small range. The Shark-Hartmann sensor was used to investigate the wavefront aberration induced by turbulent flow and temperature gradient. According to the wavefront and fluid mechanics analysis, it is considered that the periodic intra-cavity loss can be attributed to turbulent flow and temperature gradient.

  14. Determination of the decay parameters of resonant states

    International Nuclear Information System (INIS)

    Tsoupas, N.

    1975-01-01

    The partial decay proton widths and the relative phases of six of the resonances in 29 P from excitation energies 5.7 to 7.1 MeV were determined. For this determination the angular distributions of protons scattered inelastically from the first 2 + excited state in 28 Si have been measured at 88 energies between E/sub p/ = 3.0 to 5.2 MeV. The coefficients describing the angular distributions were extracted from the experimental data and plotted as a function of C.M. bombarding energy over the resonance region. In addition triple angular correlations in the spin-flip geometry of the inelastically scattered protons from the 2 + first excited state of 28 Si with the γ-rays resulted from the de-excitation of 28 Si to its ground state were performed over the energy region E/sub p/ = 3.0 to 4.7 MeV. The coefficients describing these triple angular correlations were extracted and plotted versus C.M. bombarding energy. To aid in the analysis the experimental data of another triple angular correlation in the Goldfarb-Seyler geometry between the two radiations as in the spin flip angular correlation were used. Further analysis of the experimental data for the extraction of the partial decay widths and phases proceeded by calculating the theoretical expressions of the coefficients versus energy, using a Breit-Wigner formalism including interference between the resonances. The calculated theoretical coefficients were compared with the experimental ones through an on-line interactive program which permitted visual comparisons of the theoretically calculated coefficients to the experimental coefficients. The partial decay proton widths and the relative phases for six of the resonances will be presented in this dissertation

  15. Double-Slot Hybrid Plasmonic Ring Resonator Used for Optical Sensors and Modulators

    Directory of Open Access Journals (Sweden)

    Xu Sun

    2015-11-01

    Full Text Available An ultra-high sensitivity double-slot hybrid plasmonic (DSHP ring resonator, used for optical sensors and modulators, is developed. Due to high index contrast, as well as plasmonic enhancement, a considerable part of the optical energy is concentrated in the narrow slots between Si and plasmonic materials (silver is used in this paper, which leads to high sensitivity to the infiltrating materials. By partial opening of the outer plasmonic circular sheet of the DSHP ring, a conventional side-coupled silicon on insulator (SOI bus waveguide can be used. Experimental results demonstrate ultra-high sensitivity (687.5 nm/RIU of the developed DSHP ring resonator, which is about five-times higher than for the conventional Si ring with the same geometry. Further discussions show that a very low detection limit (5.37 × 10−6 RIU can be achieved after loaded Q factor modifications. In addition, the plasmonic metal structures offer also the way to process optical and electronic signals along the same hybrid plasmonic circuits with small capacitance (~0.275 fF and large electric field, which leads to possible applications in compact high-efficiency electro-optic modulators, where no extra electrodes for electronic signals are required.

  16. Carbon-deuterium rotational-echo double-resonance NMR spectroscopy of lyophilized aspartame formulations.

    Science.gov (United States)

    Luthra, Suman A; Utz, Marcel; Gorman, Eric M; Pikal, Michael J; Munson, Eric J; Lubach, Joseph W

    2012-01-01

    In this study, changes in the local conformation of aspartame were observed in annealed lyophilized glasses by monitoring changes in the distance between two labeled sites using C-(2)H rotational-echo double-resonance (REDOR) nuclear magnetic resonance (NMR) spectroscopy. Confirmation that the REDOR experiments were producing accurate distance measurement was ensured by measuring the (13)C-(15)N distance in glycine. The experiment was further verified by measuring the REDOR dephasing curve on (13)C-(2)H methionine. (13)C-(2)H REDOR dephasing curves were then measured on lyophilized aspartame-disaccharide formulations. In aspartame-sucrose formulation, the internuclear distances increased upon annealing, which correlated with decreased chemical reactivity. By contrast, annealing had only a minimal effect on the dephasing curve in aspartame-trehalose formulation. The results show that stability is a function of both mobility and local structure (conformation), even in a small molecule system such as lyophilized aspartame-sucrose. Copyright © 2011 Wiley-Liss, Inc.

  17. Development of CdTe/Cd1-xMgxTe double barrier, single quantum well heterostructure for resonant tunneling

    International Nuclear Information System (INIS)

    Reuscher, G.; Keim, M.; Fischer, F.; Waag, A.; Landwehr, G.

    1995-01-01

    We report the first observation of resonant tunneling through a CdTe/Cd 1-x Mg x Te double barrier, single quantum well heterostructure. Negative differential resistance is observable at temperatures below 230 K, exhibiting a peak to valley ratio of 3:1 at 4.2 K. (author)

  18. Nonequilibrium Green's function theory of resonant steady state photoconduction in a double quantum well FET subject to THz radiation at plasmon frequency

    International Nuclear Information System (INIS)

    Horing, Norman J Morgenstern; Popov, Vyacheslav V

    2006-01-01

    Recent experimental observations by X.G. Peralta and S.J. Allen, et al. of dc photoconductivity resonances in steady source-drain current subject to terahertz radiation in a grid-gated double-quantum well FET suggested an association with plasmon resonances. This association was definitively confirmed for some parameter ranges in our detailed electrodynamic absorbance calculations. In this paper we propose that the reason that the dc photoconductance resonances match the plasmon resonances in semiconductors is based on a nonlinear dynamic screening mechanism. In this, we employ a shielded potential approximation that is nonlinear in the terahertz field to determine the nonequilibrium Green's function and associated density perturbation that govern the nonequilibrium dielectric polarization of the medium. This 'conditioning' of the system by the incident THz radiation results in resonant polarization response at the plasmon frequencies which, in turn, causes a sharp drop of the resistive shielded impurity scattering potentials and attendant increase of the dc source-drain current. This amounts to disabling the impurity scattering mechanism by plasmon resonant behavior in nonlinear screening

  19. Determination of contraband using fast neutron resonance technique

    Energy Technology Data Exchange (ETDEWEB)

    Bae, J.; Whang, J. [Kyunghee Univ., Dept. of Nuclear Engineering, Yongin-shi, Kyongki-do (Korea, Republic of)

    2004-07-01

    'Full-text:' Resonance technique with monoenergetic fast neutron beam is able to map features in bulk samples in a way that is sensitive to their elemental composition. It has a number of potential applications, for example, in mining and in the detection of contraband materials such as illicit drugs and explosives. By moving around the neutron detector experiences neutrons in the form of narrow line beam with different energies as the angle to the neutron source changes. Projection data was obtained using the Monte Carlo code MCNP4C. Therefore the fast neutrons scattered from an unknown object are used to determine the elemental content of the object and hence lead to its identification. Scattered features simulated for various test materials are analyzed using the HEPRO program system (PTB, Braunschweig) to determine the atom weight fractions for H. C. N, O and other elements in the materials. Atom weight fractions determined from scattering features are insensitive to neutron interactions in interfering materials surrounding the object. The simulations demonstrate that the fast neutron resonance technique (FNRT) provides reliable elemental characterization of bulk materials and has the necessary sensitivity to distinguish between drugs, explosives and other materials. (author)

  20. Determination of contraband using fast neutron resonance technique

    International Nuclear Information System (INIS)

    Bae, J.; Whang, J.

    2004-01-01

    'Full-text:' Resonance technique with monoenergetic fast neutron beam is able to map features in bulk samples in a way that is sensitive to their elemental composition. It has a number of potential applications, for example, in mining and in the detection of contraband materials such as illicit drugs and explosives. By moving around the neutron detector experiences neutrons in the form of narrow line beam with different energies as the angle to the neutron source changes. Projection data was obtained using the Monte Carlo code MCNP4C. Therefore the fast neutrons scattered from an unknown object are used to determine the elemental content of the object and hence lead to its identification. Scattered features simulated for various test materials are analyzed using the HEPRO program system (PTB, Braunschweig) to determine the atom weight fractions for H. C. N, O and other elements in the materials. Atom weight fractions determined from scattering features are insensitive to neutron interactions in interfering materials surrounding the object. The simulations demonstrate that the fast neutron resonance technique (FNRT) provides reliable elemental characterization of bulk materials and has the necessary sensitivity to distinguish between drugs, explosives and other materials. (author)

  1. Double-wavelength overlapping resonance Rayleigh scattering technique for the simultaneous quantitative analysis of three β-adrenergic blockade

    Science.gov (United States)

    Tan, Xuanping; Yang, Jidong; Li, Qin; Yang, Qiong; Shen, Yizhong

    2016-05-01

    Four simple and accurate spectrophotometric methods were proposed for the simultaneous determination of three β-adrenergic blockade, e.g. atenolol, metoprolol and propranolol. The methods were based on the reaction of the three drugs with erythrosine B (EB) in a Britton-Robinson buffer solution at pH 4.6. EB could combine with the drugs to form three ion-association complexes, which resulted in the resonance Rayleigh scattering (RRS) intensity that is enhanced significantly with new RRS peaks that appeared at 337 nm and 370 nm, respectively. In addition, the fluorescence intensity of EB was also quenched. The enhanced scattering intensities of the two peaks and the fluorescence quenched intensity of EB were proportional to the concentrations of the drugs, respectively. What is more, the RRS intensity overlapped with the double-wavelength of 337 nm and 370 nm (so short for DW-RRS) was also proportional to the drugs concentrations. So, a new method with highly sensitive for simultaneous determination of three bisoprolol drugs was established. Finally, the optimum reaction conditions, influencing factors and spectral enhanced mechanism were investigated. The new DW-RRS method has been applied to simultaneously detect the three β-blockers in fresh serum with satisfactory results.

  2. Rotational-echo Double-resonance in Complex Biopolymers: a Study of Nephila Clavipes Dragline Silk

    International Nuclear Information System (INIS)

    Michal, Carl A.; Jelinski, Lynn W.

    1998-01-01

    Rotational-Echo Double-Resonance (REDOR) NMR on strategically 13C and 15N labeled samples is used to study the conformation of the LGXQ (X = S, G, or N) motif in the major ampullate gland dragline silk from the spider Nephila clavipes. A method is described for calculating REDOR dephasing curves suitable for background subtractions, using probability distributions of nitrogen atoms surrounding a given carbon site, which are developed from coordinates in the Brookhaven Protein Data Bank. The validity of the method is established by comparison to dephasings observed from natural abundance 13C peaks for G and A. Straightforward fitting of universal REDOR dephasing curves to the background corrected peaks of interest provide results which are not self-consistent, and a more sophisticated analysis is developed which better accounts for 15N labels which have scrambled from the intended positions. While there is likely some heterogeneity in the structures formed by the LGXQ sequences, the data indicate that they all form compact turn-like structures

  3. Spectral relationships between kicked Harper and on-resonance double kicked rotor operators

    International Nuclear Information System (INIS)

    Lawton, Wayne; Mouritzen, Anders S.; Wang Jiao; Gong Jiangbin

    2009-01-01

    Kicked Harper operators and on-resonance double kicked rotor operators model quantum systems whose semiclassical limits exhibit chaotic dynamics. Recent computational studies indicate a striking resemblance between the spectra of these operators. In this paper we apply C*-algebra methods to explain this resemblance. We show that each pair of corresponding operators belongs to a common rotation C*-algebra B α , prove that their spectra are equal if α is irrational, and prove that the Hausdorff distance between their spectra converges to zero as q increases if α=p/q with p and q coprime integers. Moreover, we show that corresponding operators in B α are homomorphic images of mother operators in the universal rotation C*-algebra A α that are unitarily equivalent and hence have identical spectra. These results extend analogous results for almost Mathieu operators. We also utilize the C*-algebraic framework to develop efficient algorithms to compute the spectra of these mother operators for rational α and present preliminary numerical results that support the conjecture that their spectra are Cantor sets if α is irrational. This conjecture for almost Mathieu operators, called the ten Martini problem, was recently proven after intensive efforts over several decades. This proof for the almost Mathieu operators utilized transfer matrix methods, which do not exist for the kicked operators. We outline a strategy, based on a special property of loop groups of semisimple Lie groups, to prove this conjecture for the kicked operators

  4. Evaluation of colonic involvement in endometriosis: double-contrast barium enema vs. magnetic resonance imaging.

    Science.gov (United States)

    Faccioli, N; Foti, G; Manfredi, R; Mainardi, P; Spoto, E; Ruffo, G; Minelli, L; Mucelli, R Pozzi

    2010-08-01

    The purpose of the study was to compare the accuracy of double-contrast barium enema (DCBE) and magnetic resonance imaging (MRI) in the diagnosis of intestinal endometriosis using the histological examination on resected specimen as comparative standard. Eighty-three consecutive patients with suspected intestinal endometriosis, resected between 2005 and 2007, were prospectively evaluated. All of the women underwent preoperative DCBE and MRI on the same day. We evaluated number, site (rectum, sigmoid, cecum), and size of the lesions. The imaging findings were correlated with those resulting at pathology. Among the 65 women who underwent surgery, 50/65 (76.9%) were found to have bowel endometriosis, with 9/50 (18%) patients presenting two lesions; DCBE allowed to detect 50/59 (84.7%) lesions. MRI allowed to detect 42/59 (71.1%) lesions. DCBE showed sensibility, specificity, PPV, NPV, and accuracy of respectively 84.7, 93.7, 98.0, 62.5, and 86.6%, MRI of 71.1, 83.3, 93.3, 46.8, and 74.6%. DCBE is more accurate than unenhanced MRI in the diagnosis of bowel endometriosis, and should be preferred in the preoperative management of this disease, since it usually enables a proper surgical planning.

  5. Correlation between magnetic properties and nuclear magnetic resonance observations in Sr2FeMoO6 double perovskite

    International Nuclear Information System (INIS)

    Colis, S.; Pourroy, G.; Panissod, P.; Meny, C.; Dinia, A.

    2004-01-01

    We present the influence of the sintering temperature on the magnetic properties of Sr 2 FeMoO 6 double perovskite, on the basis of magnetization and nuclear magnetic resonance (NMR) measurements. Interestingly, the saturation magnetization originating mainly from the Fe moments is correlated with the amount of Mo magnetic moments observed by NMR measurements. We show that there is an optimum temperature of 1000 deg. C for which the reaction leading to the double perovskite becomes more advanced and/or the number of antisite defects is minimum

  6. Pitchfork bifurcation and vibrational resonance in a fractional-order ...

    Indian Academy of Sciences (India)

    The fractional-order damping mainly determines the pattern of the vibrational resonance. There is a bifurcation point of the fractional order which, in the case of double-well potential, transforms vibrational resonance pattern from a single resonance to a double resonance, while in the case of single-well potential, transforms ...

  7. Cyclotron resonance study of the two-dimensional electron layers and double layers in tilted magnetic fields

    Czech Academy of Sciences Publication Activity Database

    Goncharuk, Natalya; Smrčka, Ludvík; Kučera, Jan

    2004-01-01

    Roč. 22, - (2004), s. 590-593 ISSN 1386-9477. [International Conference on Electronic Properties of Two-Dimensional Systems /15./. Nara, 14.07.2003-18.07.2003] R&D Projects: GA ČR GA202/01/0754 Institutional research plan: CEZ:AV0Z1010914 Keywords : single layer * double layer * two-dimensional electron system * cyclotron resonance Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.898, year: 2004

  8. Liquid-Liquid Phase Separation in Model Nuclear Waste Glasses: A Solid-State Double-Resonance NMR Study

    Energy Technology Data Exchange (ETDEWEB)

    Martineau, Ch.; Michaelis, V.K.; Kroeker, S. [Univ Manitoba, Dept Chem, Winnipeg, MB R3T 2N2 (Canada); Schuller, S. [CEA Valrho Marcoule, LDMC, SECM, DTCD, DEN, F-30207 Bagnols Sur Ceze (France)

    2010-07-01

    Double-resonance nuclear magnetic resonance (NMR) techniques are used in addition to single-resonance NMR experiments to probe the degree of mixing between network-forming cations Si and B, along with the modifier cations Cs{sup +} and Na{sup +} in two molybdenum-bearing model nuclear waste glasses. The double-resonance experiments involving {sup 29}Si in natural abundance are made possible by the implementation of a CPMG pulse-train during the acquisition period of the usual REDOR experiments. For the glass with lower Mo content, the NMR results show a high degree of Si-B mixing, as well as an homogeneous distribution of the cations within the borosilicate network, characteristic of a non-phase-separated glass. For the higher-Mo glass, a decrease of B-Si(Q{sup 4}) mixing is observed, indicating phase separation. {sup 23}Na and {sup 133}Cs NMR results show that although the Cs{sup +} cations, which do not seem to be influenced by the molybdenum content, are spread within the borate network, there is a clustering of the Na{sup +} cations, very likely around the molybdate units. The segregation of a Mo-rich region with Na{sup +} cations appears to shift the bulk borosilicate glass composition toward the metastable liquid liquid immiscibility region and induce additional phase separation. Although no crystallization is observed in the present case, this liquid liquid phase separation is likely to be the first stage of crystallization that can occur at higher Mo loadings or be driven by heat treatment. From this study emerges a consistent picture of the nature and extent of such phase separation phenomena in Mo-bearing glasses, and demonstrates the potential of double-resonance NMR methods for the investigation of phase separation in amorphous materials. (authors)

  9. Double parametric resonance for matter-wave solitons in a time-modulated trap

    International Nuclear Information System (INIS)

    Baizakov, Bakhtiyor; Salerno, Mario; Filatrella, Giovanni; Malomed, Boris

    2005-01-01

    We analyze the motion of solitons in a self-attractive Bose-Einstein condensate, loaded into a quasi-one-dimensional parabolic potential trap, which is subjected to time-periodic modulation with an amplitude ε and frequency Ω. First, we apply the variational approximation, which gives rise to decoupled equations of motion for the center-of-mass coordinate of the soliton, ξ(t), and its width a(t). The equation for ξ(t) is the ordinary Mathieu equation (ME) (it is an exact equation that does not depend on the adopted ansatz), the equation for a(t) being a nonlinear generalization of the ME. Both equations give rise to the same map of instability zones in the (ε,Ω) plane, generated by the parametric resonances (PRs), if the instability is defined as the onset of growth of the amplitude of the parametrically driven oscillations. In this sense, the double PR is predicted. Direct simulations of the underlying Gross-Pitaevskii equation give rise to a qualitatively similar but quantitatively different stability map for oscillations of the soliton's width a(t). In the direct simulations, we identify the soliton dynamics as unstable if the instability (again, realized as indefinite growth of the amplitude of oscillations) can be detected during a time comparable with, or smaller than, the lifetime of the condensate (therefore accessible to experimental detection). Two-soliton configurations are also investigated. It is concluded that multiple collisions between solitons are elastic, and they do not affect the instability borders

  10. Magnetic resonance evaluation of anterior cruciate ligament repair using the patellar tendon double bone block technique

    International Nuclear Information System (INIS)

    Autz, G.; Singson, R.D.; Goodwin, C.

    1991-01-01

    The magnetic resonance (MR) appearance of the anterior cruciate ligament reconstruction was determined in 20 clinically stable and 2 clinically unstable knees for a total of 22 examinations. All patients studied had undergone knee reconstruction using the patellar tendon as graft material. The reconstructed anterior cruciate ligament varies in appearance. It appeared as a thick, well-defined, low signal band on T1- and T2-weighted sagittal and coronal images in 14 of 22 examinations. The remaining 8 knees showed a graft having one or more thin and attenuated, low signal intensity bands in the sagittal and/or coronal plane. Arthroscopy confirmed an intact but lax graft in the clinically unstable knees. (orig.)

  11. Magnetic resonance evaluation of anterior cruciate ligament repair using the patellar tendon double bone block technique

    Energy Technology Data Exchange (ETDEWEB)

    Autz, G.; Singson, R.D. (St. Luke' s Roosevelt Hospital Center, New York, NY (United States). Dept. of Radiology); Goodwin, C. (St. Luke' s Roosevelt Hospital Center, New York, NY (United States). Dept. of Orthopedics)

    1991-11-01

    The magnetic resonance (MR) appearance of the anterior cruciate ligament reconstruction was determined in 20 clinically stable and 2 clinically unstable knees for a total of 22 examinations. All patients studied had undergone knee reconstruction using the patellar tendon as graft material. The reconstructed anterior cruciate ligament varies in appearance. It appeared as a thick, well-defined, low signal band on T1- and T2-weighted sagittal and coronal images in 14 of 22 examinations. The remaining 8 knees showed a graft having one or more thin and attenuated, low signal intensity bands in the sagittal and/or coronal plane. Arthroscopy confirmed an intact but lax graft in the clinically unstable knees. (orig.).

  12. Microwave-optical double resonance spectroscopy. Progress report, February 1, 1976--January 31, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Pratt, D.W.

    1976-11-01

    Zero-field and high-field optical detection of magnetic resonance (ODMR), electron paramagnetic resonance (EPR), and optical spectroscopy experiments have been performed on several systems in order to further basic knowledge of the structure, reactions, and response to radiation of atoms, molecules, and ions in their ground and/or excited electronic states. Particularly noteworthy results for the present contract year include the determination of the complete magnetic and optical properties of the lowest triplet states of 1-chloro, 1-bromo, and 1-iodonaphthalene, the development of a microscopic model for the intramolecular heavy-atom effect in the /sup 3/(..pi..,..pi..*) states of aromatic molecules, a detailed analysis of the angular dependence of the hyperfine and quadrupole structure in triplet 1-bromonaphthalene, observation of proton hyperfine structure in the hf ODMR spectra of short-lived triplet states, a definitive paper on the relative importance of spin delocalization and second-order spin-orbit coupling effects in /sup 3/(n,..pi..*) benzophenone (a phototype photochemical system), a detailed analysis of the level-anticrossing spectra of several triplet state benzophenones which exhibit hyperfine structure in the cross-relaxation region (thus permitting the determination of key magnetic parameters in the complete absence of perturbing microwave or radiofrequency fields), optical detection of ground-state NQR transitions in host crystal molecules, the observation of strong radiofrequency transitions near avoided crossing points in Zeeman energy level diagrams of photoexcited triplet states, the construction of zero-field ODMR, ODENDOR, and hf ODENDOR spectrometers, measurements of the activation parameters for ring interconversions of several free radicals containing five- and six-membered rings, and experimental proof that the triplet state of trimethylenemethane (a key reactive intermediate in organic chemistry) is the ground state.

  13. A study of relaxation mechanisms in the A{sup 2}{Sigma}{sup +} state of nitric oxide by time resolved double resonant polarization spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Stampanoni-Panariello, A; Bombach, R; Hemmerling, B; Hubschmid, W [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    Double resonant polarization labeling spectroscopy is applied to detect nitric oxide in flames and to characterize rotational energy transfer and orientation changing collisions in its first excited electronic state. (author) 4 figs., 3 refs.

  14. Determination of trace elements by resonant ionization mass spectrometry (RIMS)

    International Nuclear Information System (INIS)

    Ruster, W.; Ames, F.; Rehklau, D.; Mang, M.; Muehleck, C.; Rimke, H.; Sattelberger, P.; Herrmann, G.; Trautmann, N.; Kluge, H.J.; Otten, E.W.

    1988-01-01

    A resonant ionization mass spectrometer has been developed as an analytical tool for the detection of trace elements, especially of plutonium and other radionuclides. The sample, deposited on a rhenium filament, is evaporated by electrical heating and the atoms of the element under investigation are selectively ionized by laser light delivered from three dye lasers pumped by a copper vapour laser. The resulting photoions are detected in a time-of-flight spectrometer with a channelplate detector. For plutonium a mass resolution of M/ΔM=1500 was obtained and an overall detection efficiency of 4x10 -6 was determined for stepwise excitation and ionization via autoionizing states. With a laser light bandwidth of 3-5 GHz neighbouring isotopes could be suppressed by a factor of 20 due to isotope shifts in the excitation transitions. The isotope composition of synthetic samples was measured and good agreement was found with mass spectroscopic results. The influence of the hyperfine structure on the isotope ratios is discussed. (orig.)

  15. Exploring the resonant vibration of thin plates: Reconstruction of Chladni patterns and determination of resonant wave numbers.

    Science.gov (United States)

    Tuan, P H; Wen, C P; Chiang, P Y; Yu, Y T; Liang, H C; Huang, K F; Chen, Y F

    2015-04-01

    The Chladni nodal line patterns and resonant frequencies for a thin plate excited by an electronically controlled mechanical oscillator are experimentally measured. Experimental results reveal that the resonant frequencies can be fairly obtained by means of probing the variation of the effective impedance of the exciter with and without the thin plate. The influence of the extra mass from the central exciter is confirmed to be insignificant in measuring the resonant frequencies of the present system. In the theoretical aspect, the inhomogeneous Helmholtz equation is exploited to derive the response function as a function of the driving wave number for reconstructing experimental Chladni patterns. The resonant wave numbers are theoretically identified with the maximum coupling efficiency as well as the maximum entropy principle. Substituting the theoretical resonant wave numbers into the derived response function, all experimental Chladni patterns can be excellently reconstructed. More importantly, the dispersion relationship for the flexural wave of the vibrating plate can be determined with the experimental resonant frequencies and the theoretical resonant wave numbers. The determined dispersion relationship is confirmed to agree very well with the formula of the Kirchhoff-Love plate theory.

  16. Discrete ambiguity resolution and baryon-resonance parameter determination

    International Nuclear Information System (INIS)

    Chew, D.M; Urban, M.

    1978-04-01

    A partial-wave analysis was performed on elastic π + p data between 1400 and 2200 MeV, using principles of analyticity (to select and amalgamate data), causality and unitarity together with Barrelet zeros are the resonating waves between 1500 and 1800 MeV examined in detail, and it is shown how a new resolution of the discrete ambiguity gives, for the S31 and D33 resonances, different parameters than found in an earlier resolution using less accurate information. In either case, mass degeneracy of these resonances is observed in agreement with general considerations regarding smooth zero trajectories. 18 references

  17. Control of slow-to-fast light and single-to-double optomechanically induced transparency in a compound resonator system: A theoretical approach

    Science.gov (United States)

    Ziauddin; Rahman, Mujeeb ur; Ahmad, Iftikhar; Qamar, Sajid

    2017-10-01

    The transmission characteristics of probe light field is investigated theoretically in a compound system of two coupled resonators. The proposed system consisted of two high-Q Fabry-Perot resonators in which one of the resonators is optomechanical. Optomechanically induced transparency (OMIT), having relatively large window, is noticed via strong coupling between the two resonators. We investigate tunable switching from single to double OMIT by increasing amplitude of the pump field. We notice that, control of slow and fast light can be obtained via the coupling strength between the two resonators.

  18. Multinuclear solid-state high-resolution and C-13 -{Al-27} double-resonance magic-angle spinning NMR studies on aluminum alkoxides

    NARCIS (Netherlands)

    Abraham, A.; Prins, R.; Bokhoven, J.A. van; Eck, E.R.H. van; Kentgens, A.P.M.

    2006-01-01

    A combination of Al-27 magic-angle spinning (MAS)/multiple quantum (MQ)-MAS, C-13-H-1 CPMAS, and C-13-{Al-27} transfer of population in double-resonance (TRAPDOR) nuclear magnetic resonance (NMR) were used for the structural elucidation of the aluminum alkoxides aluminum ethoxide, aluminum

  19. A New Hybrid Algorithm to Solve Winner Determination Problem in Multiunit Double Internet Auction

    Directory of Open Access Journals (Sweden)

    Mourad Ykhlef

    2015-01-01

    Full Text Available Solving winner determination problem in multiunit double auction has become an important E-business task. The main issue in double auction is to improve the reward in order to match the ideal prices and quantity and make the best profit for sellers and buyers according to their bids and predefined quantities. There are many algorithms introduced for solving winner in multiunit double auction. Conventional algorithms can find the optimal solution but they take a long time, particularly when they are applied to large dataset. Nowadays, some evolutionary algorithms, such as particle swarm optimization and genetic algorithm, were proposed and have been applied. In order to improve the speed of evolutionary algorithms convergence, we will propose a new kind of hybrid evolutionary algorithm that combines genetic algorithm (GA with particle swarm optimization (PSO to solve winner determination problem in multiunit double auction; we will refer to this algorithm as AUC-GAPSO.

  20. Apparatus and method for non-contact, acoustic resonance determination of intraocular pressure

    Science.gov (United States)

    Sinha, D.N.; Wray, W.O.

    1994-12-27

    The apparatus and method for measuring intraocular pressure changes in an eye under investigation by detection of vibrational resonances therein. An ultrasonic transducer operating at its resonant frequency is amplitude modulated and swept over a range of audio frequencies in which human eyes will resonate. The output therefrom is focused onto the eye under investigation, and the resonant vibrations of the eye observed using a fiber-optic reflection vibration sensor. Since the resonant frequency of the eye is dependent on the pressure therein, changes in intraocular pressure may readily be determined after a baseline pressure is established. 3 figures.

  1. Contribution to the study of molecular movements in cyclohexane by electron spin resonance and electron-nuclear double resonance using a radical probe; Contribution a l'etude des mouvements moleculaires dans le cyclohexane par resonance paramagnetique electronique et double resonance electronique-nucleaire a l'aide d'une sonde radicalaire

    Energy Technology Data Exchange (ETDEWEB)

    Volino, F [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1969-07-01

    Solutions of stable free radicals of the nitroxide type have been studied as a function of temperature. In the plastic or globular state, the cyclohexane molecules have rapid rotational and diffusional movements. They transmit this movement to dissolved free radicals. Conversely, measurements by electron spin resonance of the absolute movement of the radicals, and by electron nuclear double resonance of their movement relative to the cyclohexane molecules give very precise methods for local analyses of the movement present in the cyclohexane matrix. The principle of these techniques makes up the 'radical probe method'. (author) [French] Des solutions de radicaux libres stables, du type nitroxyde dans le cyclohexane ont ete etudiees, en fonction de la temperature. Les molecules de cyclohexane, dans l'etat plastique ou globulaire, sont animees de mouvements rapides de rotation sur elles-memes et de diffusion. Elles transmettent leur mobilite aux radicaux libres dissous. Reciproquement, la mesure du mouvement absolu des radicaux, a l'aide de la resonance paramagnetique electronique, et celle du mouvement relatif des radicaux et des molecules de cyclohexane par double resonance electronique-nucleaire, constituent des methodes tres precises pour analyser localement les mouvements presents dans la matrice de cyclohexane. Ce principe et ces techniques constituent la 'methode de la sonde radicalaire'. (auteur)

  2. Contribution to the study of molecular movements in cyclohexane by electron spin resonance and electron-nuclear double resonance using a radical probe; Contribution a l'etude des mouvements moleculaires dans le cyclohexane par resonance paramagnetique electronique et double resonance electronique-nucleaire a l'aide d'une sonde radicalaire

    Energy Technology Data Exchange (ETDEWEB)

    Volino, F. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1969-07-01

    Solutions of stable free radicals of the nitroxide type have been studied as a function of temperature. In the plastic or globular state, the cyclohexane molecules have rapid rotational and diffusional movements. They transmit this movement to dissolved free radicals. Conversely, measurements by electron spin resonance of the absolute movement of the radicals, and by electron nuclear double resonance of their movement relative to the cyclohexane molecules give very precise methods for local analyses of the movement present in the cyclohexane matrix. The principle of these techniques makes up the 'radical probe method'. (author) [French] Des solutions de radicaux libres stables, du type nitroxyde dans le cyclohexane ont ete etudiees, en fonction de la temperature. Les molecules de cyclohexane, dans l'etat plastique ou globulaire, sont animees de mouvements rapides de rotation sur elles-memes et de diffusion. Elles transmettent leur mobilite aux radicaux libres dissous. Reciproquement, la mesure du mouvement absolu des radicaux, a l'aide de la resonance paramagnetique electronique, et celle du mouvement relatif des radicaux et des molecules de cyclohexane par double resonance electronique-nucleaire, constituent des methodes tres precises pour analyser localement les mouvements presents dans la matrice de cyclohexane. Ce principe et ces techniques constituent la 'methode de la sonde radicalaire'. (auteur)

  3. The use of acoustically tuned resonators to improve the sound transmission loss of double-panel partitions

    Science.gov (United States)

    Mason, J. M.; Fahy, F. J.

    1988-07-01

    Double-leaf partitions are often utilized in situations requiring low weight structures with high transmission loss, an example of current interest being the fuselage walls of propeller-driven aircraft. In this case, acoustic excitation is periodic and, if one of the frequencies of excitation lies in the region of the fundamental mass-air-mass frequency of the partition, insulation performance is considerably less than desired. The potential effectiveness of tuned Helmholtz resonators connected to the partition cavity is investigated as a method of improving transmission loss. This is demonstrated by a simple theoretical model and then experimentally verified. Results show that substantial improvements may be obtained at and around the mass-air-mass frequency for a total resonator volume 15 percent of the cavity volume.

  4. Magnetic resonance signal moment determination using the Earth's magnetic field

    KAUST Repository

    Fridjonsson, Einar Orn; Creber, Sarah A.; Vrouwenvelder, Johannes S.; Johns, Michael L.

    2015-01-01

    We demonstrate a method to manipulate magnetic resonance data such that the moments of the signal spatial distribution are readily accessible. Usually, magnetic resonance imaging relies on data acquired in so-called k-space which is subsequently Fourier transformed to render an image. Here, via analysis of the complex signal in the vicinity of the centre of k-space we are able to access the first three moments of the signal spatial distribution, ultimately in multiple directions. This is demonstrated for biofouling of a reverse osmosis (RO) membrane module, rendering unique information and an early warning of the onset of fouling. The analysis is particularly applicable for the use of mobile magnetic resonance spectrometers; here we demonstrate it using an Earth's magnetic field system.

  5. Magnetic resonance signal moment determination using the Earth's magnetic field

    KAUST Repository

    Fridjonsson, Einar Orn

    2015-03-01

    We demonstrate a method to manipulate magnetic resonance data such that the moments of the signal spatial distribution are readily accessible. Usually, magnetic resonance imaging relies on data acquired in so-called k-space which is subsequently Fourier transformed to render an image. Here, via analysis of the complex signal in the vicinity of the centre of k-space we are able to access the first three moments of the signal spatial distribution, ultimately in multiple directions. This is demonstrated for biofouling of a reverse osmosis (RO) membrane module, rendering unique information and an early warning of the onset of fouling. The analysis is particularly applicable for the use of mobile magnetic resonance spectrometers; here we demonstrate it using an Earth\\'s magnetic field system.

  6. Determination of Optimal Double Sampling Plan using Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Sampath Sundaram

    2012-03-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Designing double sampling plan requires identification of sample sizes and acceptance numbers. In this paper a genetic algorithm has been designed for the selection of optimal acceptance numbers and sample sizes for the specified producer’s risk and consumer’s risk. Implementation of the algorithm has been illustrated numerically for different choices of quantities involved in a double sampling plan   

  1. Electron paramagnetic resonance and electron-nuclear double resonance study of the neutral copper acceptor in ZnGeP sub 2 crystals

    CERN Document Server

    Stevens, K T; Setzler, S D; Schünemann, P G; Pollak, T M

    2003-01-01

    Electron paramagnetic resonance (EPR) and electron-nuclear double resonance have been used to characterize the neutral copper acceptor in ZnGeP sub 2 crystals. The copper substitutes for zinc and behaves as a conventional acceptor (i.e. the 3d electrons do not play a dominant role). Because of a high degree of compensation from native donors, the copper acceptors in our samples were initially in the nonparamagnetic singly ionized state (Cu sub Z sub n sup -). The paramagnetic neutral state (Cu sub Z sub n sup 0) was observed when the crystals were exposed to 632.8 nm or 1064 nm laser light while being held at a temperature below 50 K. The g matrix of the neutral copper acceptor is axial g sub p sub a sub r = 2.049 and g sub p sub e sub r sub p = 2.030), with the unique principal direction parallel to the tetragonal c axis of the crystal. The hyperfine and nuclear quadrupole matrices also exhibit c-axis symmetry (A sub p sub a sub r = 87.6 MHz, A sub p sub e sub r sub p = 34.8 MHz and P = 0.87 MHz for sup 6 su...

  2. Sub-natural linewidth resonances in coherently-driven double Λ ...

    Indian Academy of Sciences (India)

    Using the master equation approach, analytical results are obtained for the absorption spectrum of a weak probe in the presence of a strong pump. The model is applied to the double system 52 1/2 = 1, 2 → 523/2 ' = 1, 2 of 87Rb atom. It is shown that the absorption spectrum consists of a triplet, of which one ...

  3. Displacement and resonance behaviors of a piezoelectric diaphragm driven by a double-sided spiral electrode

    KAUST Repository

    Shen, Zhiyuan; Olfatnia, Mohammad; Miao, Jianmin; Wang, Zhihong

    2012-01-01

    This paper presents the design of a lead zirconate titanate (PZT) diaphragm actuated by double-sided patterned electrodes. Au/Cr electrodes were deposited on bulk PZT wafers by sputtering while patterned by a lift-off process. SU-8 thick film

  4. High data density and capacity in chipless radiofrequency identification (chipless-RFID) tags based on double-chains of S-shaped split ring resonators (S-SRRs)

    Science.gov (United States)

    Herrojo, Cristian; Mata-Contreras, Javier; Paredes, Ferran; Martín, Ferran

    2017-11-01

    The data density per surface (DPS) is a figure of merit in chipless radiofrequency identification (chipless-RFID) tags. In this paper, it is demonstrated that chipless-RFID tags with high DPS can be implemented by using double-chains of S-shaped split ring resonators (S-SRRs). Tag reading is achieved by near-field coupling between the tag and the reader, a CPW transmission line fed by a harmonic signal tuned to the resonance frequency of the S-SRRs. By transversally displacing the tag over the CPW, the transmission coefficient of the line is modulated by tag motion. This effectively modulates the amplitude of the injected (carrier) signal at the output port of the line, and the identification (ID) code, determined by the presence or absence of S-SRRs at predefined and equidistant positions in the chains, is contained in the envelope function. The DPS is determined by S-SRR dimensions and by the distance between S-SRRs in the chains. However, by using two chains of S-SRRs, the number of bits per unit length that can be accommodated is very high. This chipless-RFID system is of special interest in applications where the reading distance can be sacrificed in favor of data capacity (e.g., security and authentication). Encoding of corporate documents, ballots, exams, etc., by directly printing the proposed tags on the item product to prevent counterfeiting is envisaged.

  5. Noise reduction in double-panel structures by cavity and panel resonance control

    NARCIS (Netherlands)

    Ho, J.-H.; Berkhoff, A.P

    2011-01-01

    This paper presents an investigation of the cavity and the panel resonance control in a double‐panel structure. The double‐panel structure, which consists of two panels with air in the gap, is widely adopted in many applications such as aerospace due to its light weight and effective

  6. Ferromagnetic resonance in coupled permalloy double films separated by a Cu interlayer

    Science.gov (United States)

    Maksymowicz, A. Z.; Whiting, J. S. S.; Watson, M. L.; Chambers, A.

    1991-03-01

    Ferromagnetic resonance (FMR) at 16 GHz was used to study the magnetic coupling between two-layers of permalloy separated by a nonmagnetic Cu layer. Samples with the same thickness (600 Å) of both permalloy layers were deposited from e-gun sources onto glass substrates in UHV. The thickness d of the Cu interlayer was varied from 5 to 37 Å. The exchange coupling energy ( E = - KM1· M2) model was used to describe the interaction between the two magnetic layers. It was found from the ferromagnetic resonance data in the perpendicular configuration that K( d) follows an exponential law, K = K0e - d/ q, where q = 9.3 Å.

  7. Determination of cerebral perfusion using magnetic resonance imaging

    International Nuclear Information System (INIS)

    Ropele, S.

    1997-01-01

    This thesis deals with various magnetic resonance imaging methods to quantify cerebral blood flow. Special attention has been drawn to noninvasive methods. A new method based on the T1-shortening due to perfusion was developed using a multipoint inversion recovery sequence with alternating slice selective and non selective preparation. To study the influence of errors arising from partial volume effects with cerebrospinal fluid and from brain motion, numerous investigations have been performed on a clinical 1.5 Tesla scanner. In a second approach, the IVIM-method, which treats isotropic movement in the capillary network like diffusion, has been investigated. Since artifacts in phase encoding direction caused by brain motion are a common problem to most diffusion imaging techniques, a significant improvement has been achieved by the development and optimization of a single shot STEAM-sequence. This sequence proved to be less sensitive for motion artifacts, although a high signal to noise ratio has been preserved. (author)

  8. Determining phenols in coal conversion products by nuclear magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Kanitskaya, L.V.; Kushnarev, D.F.; Polonov, V.M.; Kalabin, G.A.

    1985-03-01

    Possibility of using nuclear magnetic resonance spectra of the hydrogen 1 (/sup 1/H) isotope for a qualitative and quantitative evaluation of the hydroxyl groups in the products of coal processing is investigated. The basis of the method is the fact that in NMR spectra of the /sup 1/H in organic compounds with acid protons, the latter are unprotected when strong bases are used as solvents because of intermolecular hydrogen bonds. The resin from the medium-temperature semicoking of Cheremkhovskii coals, its hydrogenate, and phenol fraction of the hydrogenate were used for the investigation. The results were compared with the results of other NMR spectroscopy methods. The high solubility of hexamethanol and the fact that the products can be analyzed in the natural state, are some advantages of the method. 18 references.

  9. Microwave-optical double resonance spectroscopy. Progress report, February 1, 1975--January 31, 1976

    International Nuclear Information System (INIS)

    Pratt, D.W.

    1975-01-01

    Zero-field and high-field optical detection of magnetic resonance (ODMR), electron paramagnetic resonance (EPR), and optical spectroscopy experiments were performed on several systems in order to further basic knowledge of the structure, reactions, and response to radiation of atoms, molecules, and ions. Results on the following studies are reported: the direct observation of level anticrossing and mixing effects in excited molecular triplet states; anomalous zero-field splittings in the lowest triplet state of 1-iodonaphthalene; evidence for second-order spin-orbit coupling and spin delocalization effects in the lowest triplet state of benzophenone; direct observation of the optical absorption spectra of reactive free radicals at room temperature; measurements of the activation and thermodynamic parameters of several cyclohexenyl and cyclohexanonyl radicals; complete analyses of the level anticrossing and cross relaxation spectra of oriented molecular triplet states; solutions to the spin Hamiltonian for S = 1, I = 5/2 systems in both zero-field and high-field, an improvement by a factor of ten in the resolution of ODMR experiments in high field; and measurements of the optical and magnetic resonance properties of a series of halogenated naphthalenes in their lowest triplet states

  10. Modeling and optimization of a double-well double-barrier GaN/AlGaN/GaN/AlGaN resonant tunneling diode

    Science.gov (United States)

    Liu, Yang; Gao, Bo; Gong, Min; Shi, Ruiying

    2017-06-01

    The influence of a GaN layer as a sub-quantum well for an AlGaN/GaN/AlGaN double barrier resonant tunneling diode (RTD) on device performance has been investigated by means of numerical simulation. The introduction of the GaN layer as the sub-quantum well turns the dominant transport mechanism of RTD from the 3D-2D model to the 2D-2D model and increases the energy difference between tunneling energy levels. It can also lower the effective height of the emitter barrier. Consequently, the peak current and peak-to-valley current difference of RTD have been increased. The optimal GaN sub-quantum well parameters are found through analyzing the electrical performance, energy band, and transmission coefficient of RTD with different widths and depths of the GaN sub-quantum well. The most pronounced electrical parameters, a peak current density of 5800 KA/cm2, a peak-to-valley current difference of 1.466 A, and a peak-to-valley current ratio of 6.35, could be achieved by designing RTD with the active region structure of GaN/Al0.2Ga0.8 N/GaN/Al0.2Ga0.8 N (3 nm/1.5 nm/1.5 nm/1.5 nm).

  11. Investigation of the negative differential resistance reproducibility in AlN/GaN double-barrier resonant tunnelling diodes

    Energy Technology Data Exchange (ETDEWEB)

    Boucherit, M.; Soltani, A.; Rousseau, M.; Deresmes, D.; Berthe, M.; Durand, C.; De Jaeger, J.-C. [IEMN/UMR-CNRS 8520, Universite Lille1, PRES Universite Lille Nord de France (France); Monroy, E. [Equipe mixte CEA-CNRS-UJF Nanophysique et Semiconducteurs, DRFMC/SP2M/PSC, CEA-Grenoble (France)

    2011-10-31

    AlN/GaN double-barrier resonant tunnelling diodes were grown by molecular beam epitaxy on GaN/sapphire template and processed into mesa diameters from 2 {mu}m to 4 {mu}m. The current-voltage characteristics were carried out in direct current operation and under-high vacuum. A sharp negative differential resistance (NDR) was detected in the forward bias at 120 K. The NDR was observed for the mesa size of 2 {mu}m at 4 V with a peak-to-valley current ratio of 3.5. The measurement conditions were chosen to make NDR reproducible more than 50 times and apparent in both scan voltage directions after electrical treatment.

  12. Lung lesion doubling times: values and variability based on method of volume determination

    International Nuclear Information System (INIS)

    Eisenbud Quint, Leslie; Cheng, Joan; Schipper, Matthew; Chang, Andrew C.; Kalemkerian, Gregory

    2008-01-01

    Purpose: To determine doubling times (DTs) of lung lesions based on volumetric measurements from thin-section CT imaging. Methods: Previously untreated patients with ≥ two thin-section CT scans showing a focal lung lesion were identified. Lesion volumes were derived using direct volume measurements and volume calculations based on lesion area and diameter. Growth rates (GRs) were compared by tissue diagnosis and measurement technique. Results: 54 lesions were evaluated including 8 benign lesions, 10 metastases, 3 lymphomas, 15 adenocarcinomas, 11 squamous carcinomas, and 7 miscellaneous lung cancers. Using direct volume measurements, median DTs were 453, 111, 15, 181, 139 and 137 days, respectively. Lung cancer DTs ranged from 23-2239 days. There were no significant differences in GRs among the different lesion types. There was considerable variability among GRs using different volume determination methods. Conclusions: Lung cancer doubling times showed a substantial range, and different volume determination methods gave considerably different DTs

  13. Flat-top passband filter based on parallel-coupled double microring resonators in silicon

    Science.gov (United States)

    Huang, Qingzhong; Xiao, Xi; Li, Yuntao; Li, Zhiyong; Yu, Yude; Yu, Jinzhong

    2009-08-01

    Optical filters with box-like response were designed and realized based on parallel-coupled double microrings in silicon-on-insulator. The properties of this design are simulated, considering the impact of the center-to-center distance of two rings, and coupling efficiency. Flat-top passband in the drop channel of the fabricated device was demonstrated with a 1dB bandwidth of 0.82nm, a 1dB/10dB bandwidth ratio of 0.51, an out of band rejection ratio of 14.6dB, as well as a free spectrum range of 13.6nm.

  14. New experimental determination of the neutron resonance parameters of {sup 99}Tc; Nouvelle determination experimentale des parametres de resonances neutroniques de {sup 99}Tc

    Energy Technology Data Exchange (ETDEWEB)

    Brienne-Raepsaet, C. [CEA Bruyeres-le-Chatel, 91 (France). Dept. de Physique Theorique et Appliquee]|[Aix-Marseille-1 Univ., 13 - Marseille (France)

    1999-04-01

    In order to improve nuclear data for nuclear waste transmutation cross-sections of Tc{sup 99} in the resonance energy region have been performed using the time-of-flight method at the pulsed white neutron source GELINA of the Institute for Reference Materials and Measurements, Geel, Belgium. The energy range studied spreads from 3 eV to 100 KeV. 2 kinds of measurements have been performed: capture and transmission measurements. In the energy range between 0 and 2 KeV, more than 220 resonances have been analyzed. About 130 resonances which had stayed previously undiscovered, have been detected and analyzed. Because of instability problems concerning the process of measuring itself, the systematic error is not yet determined. The accuracy which takes into account statistical and systematic errors is expected to be between 4 and 5%.

  15. Topologically determined optimal stochastic resonance responses of spatially embedded networks

    International Nuclear Information System (INIS)

    Gosak, Marko; Marhl, Marko; Korosak, Dean

    2011-01-01

    We have analyzed the stochastic resonance phenomenon on spatial networks of bistable and excitable oscillators, which are connected according to their location and the amplitude of external forcing. By smoothly altering the network topology from a scale-free (SF) network with dominating long-range connections to a network where principally only adjacent oscillators are connected, we reveal that besides an optimal noise intensity, there is also a most favorable interaction topology at which the best correlation between the response of the network and the imposed weak external forcing is achieved. For various distributions of the amplitudes of external forcing, the optimal topology is always found in the intermediate regime between the highly heterogeneous SF network and the strong geometric regime. Our findings thus indicate that a suitable number of hubs and with that an optimal ratio between short- and long-range connections is necessary in order to obtain the best global response of a spatial network. Furthermore, we link the existence of the optimal interaction topology to a critical point indicating the transition from a long-range interactions-dominated network to a more lattice-like network structure.

  16. Resonance

    DEFF Research Database (Denmark)

    Petersen, Nils Holger

    2014-01-01

    A chapter in a book about terminology within the field of medievalism: the chapter discusses the resonance of medieval music and ritual in modern (classical) music culture and liturgical practice.......A chapter in a book about terminology within the field of medievalism: the chapter discusses the resonance of medieval music and ritual in modern (classical) music culture and liturgical practice....

  17. Analysis of DNA Double-Strand Breaks and Cytotoxicity after 7 Tesla Magnetic Resonance Imaging of Isolated Human Lymphocytes

    Science.gov (United States)

    Guttek, Karina; Hartig, Roland; Godenschweger, Frank; Roggenbuck, Dirk; Ricke, Jens; Reinhold, Dirk; Speck, Oliver

    2015-01-01

    The global use of magnetic resonance imaging (MRI) is constantly growing and the field strengths increasing. Yet, only little data about harmful biological effects caused by MRI exposure are available and published research analyzing the impact of MRI on DNA integrity reported controversial results. This in vitro study aimed to investigate the genotoxic and cytotoxic potential of 7 T ultra-high-field MRI on isolated human peripheral blood mononuclear cells. Hence, unstimulated mononuclear blood cells were exposed to 7 T static magnetic field alone or in combination with maximum permissible imaging gradients and radiofrequency pulses as well as to ionizing radiation during computed tomography and γ-ray exposure. DNA double-strand breaks were quantified by flow cytometry and automated microscopy analysis of immunofluorescence stained γH2AX. Cytotoxicity was studied by CellTiter-Blue viability assay and [3H]-thymidine proliferation assay. Exposure of unstimulated mononuclear blood cells to 7 T static magnetic field alone or combined with varying gradient magnetic fields and pulsed radiofrequency fields did not induce DNA double-strand breaks, whereas irradiation with X- and γ-rays led to a dose-dependent induction of γH2AX foci. The viability assay revealed a time- and dose-dependent decrease in metabolic activity only among samples exposed to γ-radiation. Further, there was no evidence for altered proliferation response after cells were exposed to 7 T MRI or low doses of ionizing radiation (≤ 0.2 Gy). These findings confirm the acceptance of MRI as a safe non-invasive diagnostic imaging tool, but whether MRI can induce other types of DNA lesions or DNA double-strand breaks during altered conditions still needs to be investigated. PMID:26176601

  18. Double closed-loop resonant micro optic gyro using hybrid digital phase modulation.

    Science.gov (United States)

    Ma, Huilian; Zhang, Jianjie; Wang, Linglan; Jin, Zhonghe

    2015-06-15

    It is well-known that the closed-loop operation in optical gyros offers wider dynamic range and better linearity. By adding a stair-like digital serrodyne wave to a phase modulator can be used as a frequency shifter. The width of one stair in this stair-like digital serrodyne wave should be set equal to the optical transmission time in the resonator, which is relaxed in the hybrid digital phase modulation (HDPM) scheme. The physical mechanism for this relaxation is firstly indicated in this paper. Detailed theoretical and experimental investigations are presented for the HDPM. Simulation and experimental results show that the width of one stair is not restricted by the optical transmission time, however, it should be optimized according to the rise time of the output of the digital-to-analogue converter. Based on the optimum parameters of the HDPM, a bias stability of 0.05°/s for the integration time of 400 seconds in 1 h has been carried out in an RMOG with a waveguide ring resonator with a length of 7.9 cm and a diameter of 2.5 cm.

  19. Double resonance capacitance spectroscopy (DORCAS): A new experimental technique for assignment of X-ray absorption peaks to surface sites of semiconductor

    CERN Document Server

    Ishii, M

    2003-01-01

    As a new microspectroscopy for semiconductor surface analysis using an X-ray beam, double resonance capacitance spectroscopy (DORCAS) is proposed. For a microscopic X-ray absorption measurement, a local capacitance change owing to X-ray induced emission of localized electrons is detected by a microprobe. The applied bias voltage V sub b dependence of the capacitance also provides information on the surface density of state. The resonance of the Fermi energy with a surface level by V sub b control makes possible the selection of the observable surface site in the X-ray absorption measurements, i.e. site-specific spectroscopy. The double resonance of the surface site selection (V sub b resonance) and the resonant X-ray absorption of the selected site (photon energy h nu resonance) enhances the capacitance signal. The DORCAS measurement of the GaAs surface shows correlation peaks at h nu=10.402 keV and V sub b =-0.4 V and h nu=10.429 keV and V sub b =+0.1 V, indicating that these resonant X-ray absorption peaks ...

  20. Efficacy of double arterial phase dynamic magnetic resonance imaging with the sensitivity encoding technique versus dynamic multidetector-row helical computed tomography for detecting hypervascular hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Kumano, Seishi; Okada, Masahiro; Murakami, Takamichi; Uemura, Masahiko; Haraikawa, Toyoaki; Hirata, Masaaki; Kikuchi, Keiichi; Mochizuki, Teruhito; Kim, Tonsok

    2009-01-01

    The aim of this study was to evaluate the efficacy of double arterial phase dynamic magnetic resonance imaging (MRI) with the sensitivity encoding technique (SENSE dynamic MRI) for detection of hypervascular hepatocellular carcinoma (HCC) in comparison with double arterial phase dynamic multidetector-row helical computed tomography (dynamic MDCT). A total of 28 patients with 66 hypervascular HCCs underwent both double arterial SENSE dynamic MRI and dynamic MDCT. The diagnosis of HCC was based on surgical resection (n=7), biopsy (n=10), or a combination of CT during arterial portography (CTAP), CT during hepatic arteriography (CTA), and/or the 6-month follow-up CT (n=49). Based on alternative-free response receiving operating characteristic (ROC) analysis, the diagnostic performance for detecting HCC was compared between double arterial phase SENSE dynamic MRI and double arterial phase dynamic MDCT. The mean sensitivity, positive predictive value, and mean A Z values for hypervascular HCCs were 72%, 80%, and 0.79, respectively, for SENSE dynamic MRI and 66%, 92%, and 0.78, respectively, for dynamic MDCT. The mean sensitivity for double arterial phase SENSE dynamic MRI was higher than that for double arterial phase dynamic MDCT, but the difference was not statistically significant. Double arterial phase SENSE dynamic MRI is as valuable as double arterial phase dynamic MDCT for detecting hypervascular HCCs. (author)

  1. Determination of geometric inaccuracies in stereotactic magnetic resonance imaging

    International Nuclear Information System (INIS)

    Novotny, J. Jr.; Novotny, J.; Vymazal, J.

    2001-01-01

    The precision of stereotactic localization and volume determination was examined by using a Leksell's stereotactic frame, Leksell's MRI indicator box and Siemens 1 T MAGNETOM Expert scanner. The distortions in the spatial stereotactic coordinates and errors in volume determination were assessed through measurements employing a special phantom which simulated patient's head with different target volumes. The average geometrical distortion values gave evidence of a satisfactory precision for stereotactic MRI localization (average distortion 0.5 mm). No significant dependence of the magnitude of these distortions on the MRI examination sequence, MRI slice orientation, or spatial position of the measured point in the volume examined was observed. The mean percentage error of the volume determination determined by the technical capabilities of the imaging and treatment planning system was 10% for smaller volumes (below 2000 mm 3 ) and 5% for larger volumes (above 10000 mm 3 ). The subjective errors of volume determination were expressed as the standard deviation of mean volume calculated based on contours recorded by six independent observers (physicians) for each of five selected target volumes (meningioma, metastases, acoustic neurinoma, pituitary adenoma and arteriovenous malformation). The minimum standard deviation for volume recorded by six independent physicians was 5% (for metastases), the maximum value was 40 % (for arteriovenous malformation)

  2. Determination of calibration constants for perturbing objects of cavity resonators

    International Nuclear Information System (INIS)

    Franco, M.A.R.; Serrao, V.A.; Fuhrmann, C.

    1989-05-01

    Using the Slater theorem, the calibrating constants for objects utilized in the tecnique of perturbing measurements of cavities electric and magnetic fields have been determined. Such perturbing objects are utilized in the measurements of the shunt impedance and electric field relative intensity ocurring in linac accelerating structures. To determine the calibrating constants of the perturbing objects, a cylindrical cavity of well know field pattern has been utilized. The cavity was excited in two differente modes of oscillation and the experimental results are in good aggrement with the theoretical values. (author) [pt

  3. A double-layer based model of ion confinement in electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Mascali, D., E-mail: davidmascali@lns.infn.it; Neri, L.; Celona, L.; Castro, G.; Gammino, S.; Ciavola, G. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); Torrisi, G. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); Università Mediterranea di Reggio Calabria, Dipartimento di Ingegneria dell’Informazione, delle Infrastrutture e dell’Energia Sostenibile, Via Graziella, I-89100 Reggio Calabria (Italy); Sorbello, G. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); Università degli Studi di Catania, Dipartimento di Ingegneria Elettrica Elettronica ed Informatica, Viale Andrea Doria 6, 95125 Catania (Italy)

    2014-02-15

    The paper proposes a new model of ion confinement in ECRIS, which can be easily generalized to any magnetic configuration characterized by closed magnetic surfaces. Traditionally, ion confinement in B-min configurations is ascribed to a negative potential dip due to superhot electrons, adiabatically confined by the magneto-static field. However, kinetic simulations including RF heating affected by cavity modes structures indicate that high energy electrons populate just a thin slab overlapping the ECR layer, while their density drops down of more than one order of magnitude outside. Ions, instead, diffuse across the electron layer due to their high collisionality. This is the proper physical condition to establish a double-layer (DL) configuration which self-consistently originates a potential barrier; this “barrier” confines the ions inside the plasma core surrounded by the ECR surface. The paper will describe a simplified ion confinement model based on plasma density non-homogeneity and DL formation.

  4. Development of CdTe/Cd{sub 1-x}Mg{sub x}Te double barrier, single quantum well heterostructure for resonant tunneling

    Energy Technology Data Exchange (ETDEWEB)

    Reuscher, G.; Keim, M.; Fischer, F.; Waag, A.; Landwehr, G. [Physikalishes Institut der Universitaet Wuerzburg am Hubland, Wuerzburg (Germany)

    1995-12-31

    We report the first observation of resonant tunneling through a CdTe/Cd{sub 1-x}Mg{sub x}Te double barrier, single quantum well heterostructure. Negative differential resistance is observable at temperatures below 230 K, exhibiting a peak to valley ratio of 3:1 at 4.2 K. (author). 16 refs, 2 figs.

  5. Relative-coordinate determination for visual double stars by applying Fourier transforms

    Directory of Open Access Journals (Sweden)

    Radović Viktor

    2013-01-01

    Full Text Available We discuss the software developed for the purpose of determining the relative coordinates (position angle θ and separation ρ for visual double or multiple stars. It is based on application of Fourier transforms in treating CCD frames of these systems. The objective was to determine the relative coordinates automatically to an extent as large as possible. In this way the time needed for the reduction of many CCD frames becomes shorter. The capabilities and limitations of the software are examined. Besides, the possibility of improving is also considered. The software has been tested and checked on a sample consisting of CCD frames of 165 double or multiple stars obtained with the 2m telescope at NAO Rozhen in Bulgaria in October 2011. The results have been compared with the corresponding results obtained by applying different software and the agreement is found to be very good.

  6. The application of "double isolation" in Fourier transform ion cyclotron resonance sustained off-resonance irradiation collisionally-induced dissociation tandem mass spectrometry to remove labile isobaric impurities.

    Science.gov (United States)

    Gates, Paul J; Lopes, Norberto P; Pinto, Emani; Colepicolo, Pio; Cardozo, Karina H M

    2011-01-01

    This study reports the application of "double isolation" in sustained off-resonance irradiation collisionally-induced dissociation tandem mass spectrometry (SORI-CID-MS/MS) to remove radio- frequency (RF) fragment ions of very close mass isobaric ions (0.02 m/z apart). Analyses were performed with a fraction of a biological extract isolated from a macroalgae containing the mycosporine-like amino acid asterina-330. Direct isolation of the precursor ion by narrowing the isolation window proved ineffective as it impinged upon the required ion thus substantially reducing its intensity. By increasing the correlated sweep time, ejection efficiency of the isolation was improved, but caused the unwanted side-effect of RF fragmentation of labile ions. Finally, by skipping the ion activation step and performing a second isolation (in the MS(3) module) the RF fragments from the first isolation were removed leaving a very pure isolation of the required precursor ion and allowed a very clean CID fragmentation. We demonstrated that the m/z 272.1351 ion is derived from the loss of NH(3) from m/z 289.1620 isobaric impurity and is not related to asterina-330. This application represents a powerful tool to remove unwanted ions in the MS/MS spectrum that result from fragmentation of isobaric ions.

  7. Using 3.05 MeV resonance for determination of oxygen impurities

    International Nuclear Information System (INIS)

    Burkova, I.E.; Polyanskij, V.N.; Yatis, A.A.

    1983-01-01

    The method of determining oxygen impurities behind thin films using the isolated resonance in the 16 O(α, α) 16 O reaction at E=3.048 MeV with the width GITA approximately 20 keV, is considered. Cross section in resonance is σsUb(R) = 0.95 b apd it increases cross section of Rutherford scattering by the factor of 25. The conclusion is made on the possibility of using 3.048 MeV resonance when investigating Me-Si film structures

  8. Experimental determination of resonance absorption cross sections for Zircaloy-2 and zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Kocic, A; Markovic, V [Boris Kidric Institute of Nuclear Sciences, Vinca, Beograd (Yugoslavia)

    1968-05-15

    The integral absorption cross section for the neutron spectrum and the thermal absorption cross section for zircaloy-2 have been determined using the pile oscillator technique. Using both values and a measured ratio of the epithermal to the thermal flux, the effective resonance integrals were obtained. After subtraction of the contributions for alloy and impurity elements, the effective resonance integrals for zirconium were evaluated. An extrapolated value of 0.91{+-}0.10 was obtained for the dilute integral. (author)

  9. Pion double charge exchange above the Δ3/2,3/2 resonance

    International Nuclear Information System (INIS)

    Williams, A.L.

    1991-11-01

    The first exclusive measurements of (π + π - ) reactions on several nuclei for incident pion energies from 300 to 550 MeV are reported. The measurements were made with the Large Acceptance Spectrometer at the P 3 channel of the Clinton P. Anderson Meson Physics Facility. A description of the experimental setup is given which includes a discussion of modifications to the spectrometer and channel implemented specifically for these measurements. Forward angle excitation functions for transitions to the double isobaric analog state (DIAS) are found to be relatively flat for these energies. This energy dependence is reproduced by optical and Glauber calculations, but not by a six-quark bag prediction. The mass dependence of the DIAS was found to qualitatively agree with the predicted mass dependence from optical calculations. One angular distribution was measured for 5 degrees ≤ Θ lab ≤ 35 degrees for 18 O(π + π - ) 18 Ne. The DIAS cross section falls by more than one order of magnitude over this range, as predicted by both Glauber and optical model calculations. Data for f 7/2 -shell nuclei were examined with a two-amplitude model based on seniority-zero shell model wavefunctions which features expressions for cross sections for DIAS transitions and transitions to nonanalog ground-states. The cross sections for T = 1 nuclei are found to be inconsistent with the predictions of the model. One excitation function for nonanalog transitions was measured and is relatively flat with energy. The continuum of nonanalog states near threshold was found to decrease with energy

  10. EXPERIMENTAL DETERMINATION OF DOUBLE VIBE FUNCTION PARAMETERS IN DIESEL ENGINES WITH BIODIESEL

    Directory of Open Access Journals (Sweden)

    Radivoje B Pešić

    2010-01-01

    Full Text Available A zero-dimensional, one zone model of engine cycle for steady-state regimes of engines and a simplified procedure for indicator diagrams analysis have been developed at the Laboratory for internal combustion engines, fuels and lubricants of the Faculty of Mechanical Engineering in Kragujevac. In addition to experimental research, thermodynamic modeling of working process of diesel engine with direct injection has been presented in this paper. The simplified procedure for indicator diagrams analysis has been applied, also. The basic problem, a selection of shape parameters of double Vibe function used for modeling the engine operation process, has been solved. The influence of biodiesel fuel and engine working regimes on the start of combustion, combustion duration and shape parameter of double Vibe was determined by a least square fit of experimental heat release curve.

  11. High-sensitive nitrogen dioxide and ethanol gas sensor using a reduced graphene oxide-loaded double split ring resonator

    Science.gov (United States)

    Singh, Sandeep Kumar; Azad, Prakrati; Akhtar, M. J.; Kar, Kamal K.

    2017-08-01

    A reduced graphene oxide (rGO) incorporated double split ring resonator (DSRR) portable microwave gas sensor is proposed in this work. The sensor is fabricated using two major steps: the DSRR is fabricated on the FR-4 substrate, which is excited by a high impedance microstrip line. The rGO is synthesized via a chemical route and coated inside the smaller ring of the DSRR. The SEM micrographs reveal crumpled sheets of rGO that provide a large surface area, and the XRD patterns of the as-synthesized rGO reveal the two-dimensional structure of the rGO nanosheets. The sensor performance is measured at room temperature using 100-400 ppm of ethanol and NO2 target gases. At 400 ppm, the sensor reveals a shift of 420 and 390 MHz in the S 21 frequency for NO2 and ethanol gases, respectively. The frequency shifts of 130 and 120 MHz in the S 21 resonance frequency are obtained for NO2 and ethanol gases, respectively, at a very low concentration of 100 ppm. The high sensitivity of the proposed rGO gas sensor is achieved due to the combined effect of the large surface area of the rGO responsible for accommodating more gas molecules, and its increased conductivity due to the transfer of the electron from the rGO. Moreover, an exceedingly short response time is observed for NO2 in comparison to ethanol, which allows the proposed sensor to be used for the selective detection of NO2 in a harsh environment. The overall approach used in this study is quite simple, and has great potential to enhance the gas detection behaviour of rGO.

  12. A model for precalculus students to determine the resonance frequency of a trumpet mouthpiece

    Science.gov (United States)

    Chapman, Robert C.

    2004-05-01

    The trumpet mouthpiece as a Helmholtz resonator is used to show precalculus students a mathematical model for determining the approximate resonance frequency of the mouthpiece. The mathematics is limited to algebra and trigonometry. Using a system of mouthpieces that have interchangeable cups and backbores, students are introduced to the acoustics of this resonator. By gathering data on 51 different configurations of mouthpieces, the author modifies the existing Helmholtz resonator equation to account for both cup volumes and backbore configurations. Students then use this model for frequency predictions. Included are how to measure the different physical attributes of a trumpet mouthpiece at minimal cost. This includes methods for measuring cup volume, backbore volume, backbore length, throat area, etc. A portion of this phase is de-signed for students to become acquainted with some of the vocabulary of acoustics and the physics of sound.

  13. Solar Cell Capacitance Determination Based on an RLC Resonant Circuit

    Directory of Open Access Journals (Sweden)

    Petru Adrian Cotfas

    2018-03-01

    Full Text Available The capacitance is one of the key dynamic parameters of solar cells, which can provide essential information regarding the quality and health state of the cell. However, the measurement of this parameter is not a trivial task, as it typically requires high accuracy instruments using, e.g., electrical impedance spectroscopy (IS. This paper introduces a simple and effective method to determine the electric capacitance of the solar cells. An RLC (Resistor Inductance Capacitor circuit is formed by using an inductor as a load for the solar cell. The capacitance of the solar cell is found by measuring the frequency of the damped oscillation that occurs at the moment of connecting the inductor to the solar cell. The study is performed through simulation based on National Instruments (NI Multisim application as SPICE simulation software and through experimental capacitance measurements of a monocrystalline silicon commercial solar cell and a photovoltaic panel using the proposed method. The results were validated using impedance spectroscopy. The differences between the capacitance values obtained by the two methods are of 1% for the solar cells and of 9.6% for the PV panel. The irradiance level effect upon the solar cell capacitance was studied obtaining an increase in the capacitance in function of the irradiance. By connecting different inductors to the solar cell, the frequency effect upon the solar cell capacitance was studied noticing a very small decrease in the capacitance with the frequency. Additionally, the temperature effect over the solar cell capacitance was studied achieving an increase in capacitance with temperature.

  14. Resonant tunneling: A method for simultaneous determination of resonance energy and energy eigenvalue

    Energy Technology Data Exchange (ETDEWEB)

    Maiz, F., E-mail: Fethi_maiz@yahoo.fr [King Khalid University, Faculty of Science, Physics Department, P.O. Box 9004, Abha (Saudi Arabia); University of Cartage, Nabeul Engineering Preparatory Institute, Merazka, 8000 Nabeul (Tunisia); Eissa, S.A. [King Khalid University, Faculty of Science, Physics Department, P.O. Box 9004, Abha (Saudi Arabia); AL-AZHAR University, Faculty of Science, Physics Department, Nasr City, Cairo (Egypt); AlFaify, S. [King Khalid University, Faculty of Science, Physics Department, P.O. Box 9004, Abha (Saudi Arabia)

    2013-09-15

    Assuming an effective mass approximation and using Bastard's boundary conditions, a simple method for simultaneous determination of the energy levels forming the sub-band structure and the transmissions coefficient of non-symmetrical, non-periodical potential semiconducting heterostructure is being proposed. The method can be applied on a multilayer system with varying thickness and effective mass of the layers, and with potential that is neither periodical nor symmetrical. To illustrate the feasibility of the proposed method, cases of symmetrical rectangular triple-barrier structure with constant effective mass, multi-barrier semiconductor heterostructure (nine barriers–eight-wells), and monomer height barrier superlattices (300 barriers) systems have been examined. Findings show very good agreements with previously published results obtained by different methods on similar systems. The proposed method was found to be useful for any number of semiconducting layers arranged in any random way making it more realistic, simple, and applicable to superlattice analysis and for devices design.

  15. Tissue resonance interaction accurately detects colon lesions: A double-blind pilot study.

    Science.gov (United States)

    Dore, Maria P; Tufano, Marcello O; Pes, Giovanni M; Cuccu, Marianna; Farina, Valentina; Manca, Alessandra; Graham, David Y

    2015-07-07

    To investigated the performance of the tissue resonance interaction method (TRIM) for the non-invasive detection of colon lesions. We performed a prospective single-center blinded pilot study of consecutive adults undergoing colonoscopy at the University Hospital in Sassari, Italy. Before patients underwent colonoscopy, they were examined by the TRIMprobe which detects differences in electromagnetic properties between pathological and normal tissues. All patients had completed the polyethylene glycol-containing bowel prep for the colonoscopy procedure before being screened. During the procedure the subjects remained fully dressed. A hand-held probe was moved over the abdomen and variations in electromagnetic signals were recorded for 3 spectral lines (462-465 MHz, 930 MHz, and 1395 MHz). A single investigator, blind to any clinical information, performed the test using the TRIMprob system. Abnormal signals were identified and recorded as malignant or benign (adenoma or hyperplastic polyps). Findings were compared with those from colonoscopy with histologic confirmation. Statistical analysis was performed by χ(2) test. A total of 305 consecutive patients fulfilling the inclusion criteria were enrolled over a period of 12 months. The most frequent indication for colonoscopy was abdominal pain (33%). The TRIMprob was well accepted by all patients; none spontaneously complained about the procedure, and no adverse effects were observed. TRIM proved inaccurate for polyp detection in patients with inflammatory bowel disease (IBD) and they were excluded leaving 281 subjects (mean age 59 ± 13 years; 107 males). The TRIM detected and accurately characterized all 12 adenocarcinomas and 135/137 polyps (98.5%) including 64 adenomatous (100%) found. The method identified cancers and polyps with 98.7% sensitivity, 96.2% specificity, and 97.5% diagnostic accuracy, compared to colonoscopy and histology analyses. The positive predictive value was 96.7% and the negative predictive

  16. Extending double modulation: combinatorial rules for identifying the modulations necessary for determining elasticities in metabolic pathways.

    Science.gov (United States)

    Giersch, C; Cornish-Bowden, A

    1996-10-07

    The double modulation method for determining the elasticities of pathway enzymes, originally devised by Kacser & Burns (Biochem. Soc. Trans. 7, 1149-1160, 1979), is extended to pathways of complex topological structure, including branching and feedback loops. An explicit system of linear equations for the unknown elasticities is derived. The constraints imposed on this linear system imply that modulations of more than one enzyme are not necessarily independent. Simple combinatorial rules are described for identifying without using any algebra the set of independent modulations that allow the determination of the elasticities of any enzyme. By repeated application, the minimum numbers of modulations required to determine the elasticities of all enzymes of a given pathway can be determined. The procedure is illustrated with numerous examples.

  17. Sensitive double-antibody method for simultaneous determination of insulin and growth hormone

    International Nuclear Information System (INIS)

    Koparanova, O.; Sotirov, G.; Tyrkolev, N.

    1982-01-01

    A method is described for simultaneous determination of insulin and growth hormone in one sample, using double-antibody technique. The method is characterized by appreciable sensitivity (2.5 μE/ml for insulin and a.2 ng/ml for growth hormone), exactness (variation quotient 6-16 per cent) and reproducibility (96.9-117 per cent). There was no statistically significant difference in the insulin and growth hormone values of the same sera, determined by the here suggested and the standard methods. The necessary test material for examination of either hormone is minimal (0.2 ml). One may thus extend the possibilities for radioimmunologic determination of insulin and growth hormone, when only minor amounts of serum or other biological fluid are available. The method is also less time consuming. Results are reported of statistical processing of an experimental model and different sera determined by the standard method and the one described by the authors. (author)

  18. Electron spin resonance and E.N.D.O.R. double resonance study of free radicals produced by gamma irradiation of imidazole single crystals; Etude par resonance paramagnetique electronique et double resonance E.N.D.O.R. des radicaux libres crees par irradiation gamma de monocristaux d'imidazole

    Energy Technology Data Exchange (ETDEWEB)

    Lamotte, B [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1970-07-01

    Gamma irradiation of imidazole single crystals at 300 deg. K gives two radicals. Identification and detailed studies of their electronic and geometric structure have been made by ESR and ENDOR techniques. A study of the hydrogen bonded protons hyperfine tensor is made and let us conclude to the inexistence of movement and tunneling of these protons. The principal low temperature radical, produced by gamma irradiation at 77 deg. K has been also studied by ESR and a model has been proposed. (author) [French] L'irradiation gamma de monocristaux d'imidazole a 300 deg. K conduit a deux radicaux dont l'identification et l'etude detaillee des structures electroniques et geometriques ont ete obtenues par la resonance paramagnetique electronique (RPE) et la double resonance ENDOR. En particulier l'examen des protons de la liaison hydrogene permet de conclure, pour ceux-ci, a l'inexistence de tout mouvement par effet tunnel. De plus, l'analyse des spectres de RPE du radical principal cree par irradiation gamma de l'imidazole a 77 deg. K nous a permis de proposer un modele pour ce radical. (auteur)

  19. Infrared-ultraviolet double resonance: studies of molecular spectroscopy and energy transfer

    International Nuclear Information System (INIS)

    Orr, B.J.; Nutt, G.F.

    1980-01-01

    The paper demonstrates that, within the context of characterizing interactions between molecules, a new source of experimental data has become available. Recent apparatus modifications have resulted in substantially improved control of the delay between pump and probe laser pulses, with consequently improved signal-to-noise ratio and time resolution. A new phase of investigation is now underway to determine quantitively rotational relaxation rate constants as a function of angular momentum state and to model these in an appropriate fashion

  20. Resonances

    DEFF Research Database (Denmark)

    an impetus or drive to that account: change, innovation, rupture, or discontinuity. Resonances: Historical Essays on Continuity and Change explores the historiographical question of the modes of interrelation between these motifs in historical narratives. The essays in the collection attempt to realize...

  1. MULTIFREQUENCY ALGORITHMS FOR DETERMINING THE MOISTURE CONTENT OF LIQUID EMULSIONS BY THE METHOD OF RESONANCE DIELCOMETRY

    Directory of Open Access Journals (Sweden)

    A. A. Korobko

    2017-06-01

    Full Text Available Purpose. The main attention is paid to the development and investigation of multifrequency algorithms for the realization of the method of resonance dielcometric measurement of the humidity of emulsions of the type «nonpolar liquid dielectric-water». Multifrequency algorithms take into account the problem of «uncertainty of varieties» and increase the sensitivity of the dielcometric method. Methodology. Multifrequency algorithms are proposed to solve the problem of «uncertainty of varieties» and improve the metrological characteristics of the resonance dielcometric method. The essence of the algorithms is to use a mathematical model of the emulsion and to determine the permittivity of the dehydrated liquid and the emulsion. The task of developing algorithms is to determine and take into account the influence of the parasitic electrical capacitance of the measuring oscillator and the measuring transducer. The essence of the method consists in alternately determining the resonance frequency of the oscillatory circuit with various configurations, which allows to take into account errors from parasitic parameters. The problem of «uncertainty of varieties» is formulated and solved. The metrological characteristics of the resonance dielcometric method are determined using algorithms. Results. Frequency domains of application of mathematical model of an emulsion are defined. An algorithm in a general form with four frequencies suitable for practical implementation in dielcometric resonance measurements is developed. Partial algorithms with three and two frequencies are developed. The systematic values of simulation errors in the emulsion in the microwave range are determined. Generalized metrological characteristics are obtained. The ways of increasing the sensitivity of the dielcometric method are determined. The problem of «uncertainty of varieties» was solved. Experimental data on determination of humidity for the developed algorithms are

  2. Double adjoint method for determining the contribution of composition to reactivity at different times

    International Nuclear Information System (INIS)

    Christie, S.A.; Lathouwers, D.; Kloosterman, J.L.

    2013-01-01

    Highlights: ► The double adjoint method is described. ► System reloading is determined so the multiplication factor behaviour is repeated. ► Both fast and thermal systems behave as desired. ► Allowance must be made for indirect effects in thermal systems. ► An alternative definition of breeding ratio is derived. -- Abstract: The double adjoint method uses the adjoint reactivity and transmutation problems to describe how the system composition is related to the system reactivity at different points in time. Values of the contribution to the reactivity are determined using the adjoint reactivity problem, and these are then used as the source function for the adjoint transmutation problem. The method is applied to the problem of determining the contribution of the beginning of cycle composition to the end of cycle reactivity. It is tested in both fast and thermal systems by comparing the behaviour of the multiplication factor at the end of cycle in calculations with perturbed initial compositions to that predicted by the double adjoint method. The results from the fast system are good, while those from the thermal system are less favourable. This is believed to be due to the method neglecting the coupling between the composition and the flux, which plays a more significant role in thermal systems than fast ones. The importance of correcting for the effects of the fuel compound is also established. The values found are used in calculations to determine the appropriate fuel reloading of the systems tested, with the aim of duplicating the behaviour of the multiplication factor of the original system. Again the fast system gives good results, while the thermal system is less accurate. The double adjoint method is also used for a definition of breeding ratio, and some of the features of this definition are illustrated by examining the effects of different feed materials and reprocessing schemes. The method is shown to be a useful tool for the comparison of the

  3. Determination of Intermediate Resonance Parameter with RMET21 for nTRACER

    International Nuclear Information System (INIS)

    Sohail, Muhammad; Kim, Myung Hyun

    2012-01-01

    Ray Tracing based code nTRACER is being developed in Seoul National University that has the capability of 3-dimensional whole core neutron transport calculation. As a part of development of multi-group neutron cross section library for nTRACER, the current work is intended to accurately determine intermediate resonance parameters. Beside the systematic calculation of subgroup parameters for resonance self shielding calculation, intermediate resonance parameters itself can be as important as the multi-group neutron cross section in the library and its overall accuracy. In this paper lambda factors were computed using RMET21 from ENDF/B-VII.1 for nTRACER to investigate its dependence on temperature and background cross section and replaced with lambda factors from HELIOS multi-group library. The procedure used for determining the intermediate resonance parameter for the isotope under study is introduced in the next section. Oxygen being one of the primary nuclide in PWR fuel has been selected for intermediate resonance parameters calculation

  4. Magnetic Resonance Determinations of Structure and Reaction Kinetics of Epoxy/Amine Systems.

    Science.gov (United States)

    1981-12-31

    AD- AISA 542 MCDONNELL DOUGLAS RESEARCH LABS ST LOUIS MO FIG 7/4 MAGNETIC RESONANCE DETERMINATIONS OF STRUCTURE AND REACTION KIN--ETC (U) DEC Al I M...solvent content (methylene chloride). DD I JAN73 1473 EDITION OF I NOV 65 IS OBSOLETE UNCLASSIFIED SECURITY CLASSIFICATION OF THIS PAGE (When Doe Fntered

  5. Temperature dependence of the cosphi conductance in Josephson tunnel junctions determined from plasma resonance experiments

    DEFF Research Database (Denmark)

    Pedersen, Niels Falsig; Sørensen, O. H.; Mygind, Jesper

    1978-01-01

    The microwave response at 9 GHz of Sn-O-Sn tunnel-junction current biased at zero dc voltage has been measured just below the critical temperature Tc of the Sn films. The temperature dependence of the cosφ conductance is determined from the resonant response at the junction plasma frequency fp...

  6. Effect of intraarticular osmic acid on synovial membrane volume and inflammation, determined by magnetic resonance imaging

    DEFF Research Database (Denmark)

    Østergaard, Mikkel; Stoltenberg, M; Gideon, P

    1995-01-01

    The changes in MR-determined synovial membrane volume, early synovial enhancement, and cartilage and bone erosions after osmic acid knee synovectomy were studied. Gadolinium-DTPA enhanced magnetic resonance imaging (MRI) of 18 knees with persistent arthritis was performed before and 1 month after...

  7. Comparison of Langmuir probe and multipole resonance probe measurements in argon, hydrogen, nitrogen, and oxygen mixtures in a double ICP discharge

    Science.gov (United States)

    Fiebrandt, Marcel; Oberberg, Moritz; Awakowicz, Peter

    2017-07-01

    The results of a Multipole Resonance Probe (MRP) are compared to a Langmuir probe in measuring the electron density in Ar, H2, N2, and O2 mixtures. The MRP was designed for measurements in industry processes, i.e., coating or etching. To evaluate a possible influence on the MRP measurement due to molecular gases, different plasmas with increasing molecular gas content in a double inductively coupled plasma at 5 Pa and 10 Pa at 500 W are used. The determined electron densities from the MRP and the Langmuir probe slightly differ in H2 and N2 diluted argon plasmas, but diverge significantly with oxygen. In pure molecular gas plasmas, electron densities measured with the MRP are always higher than those measured with the Langmuir Probe, in particular, in oxygen containing mixtures. The differences can be attributed to etching of the tungsten wire in the Ar:O2 mixtures and rf distortion in the pure molecular discharges. The influence of a non-Maxwellian electron energy distribution function, negative ions or secondary electron emission seems to be of no or only minor importance.

  8. 3D double-echo steady-state sequence assessment of hip joint cartilage and labrum at 3 Tesla: comparative analysis of magnetic resonance imaging and intraoperative data

    Energy Technology Data Exchange (ETDEWEB)

    Schleich, Christoph; Antoch, Gerald [University of Dusseldorf, Department of Diagnostic and Interventional Radiology, Medical Faculty, Duesseldorf (Germany); Hesper, Tobias; Rettegi, Fanni; Zilkens, Christoph; Krauspe, Ruediger; Bittersohl, Bernd [University of Dusseldorf, Department of Orthopedic Surgery, Medical Faculty, Duesseldorf (Germany); Hosalkar, Harish S. [Paradise Valley Hospital, Joint Preservation and Deformity Correction, San Diego, CA (United States); Tri-city Medical Center, Hip Preservation, San Diego, CA (United States)

    2017-10-15

    To assess the diagnostic accuracy of a high-resolution, three-dimensional (3D) double-echo steady-state (DESS) sequence with radial imaging at 3 Tesla (T) for evaluating cartilage and labral alterations in the hip. Magnetic resonance imaging (MRI) data obtained at 3 T, including radially reformatted DESS images and intraoperative data of 45 patients (mean age 42 ± 13.7 years) who underwent hip arthroscopy, were compared. The acetabular cartilage and labrum of the upper hemisphere of the acetabulum and the central femoral head cartilage were evaluated. Sensitivity, specificity, accuracy, and negative and positive predictive values were determined. Sensitivity, specificity and accuracy of the DESS technique were 96.7%, 75% and 93.7% for detecting cartilage lesions and 98%, 76.2% and 95.9% for detecting labral lesions. The positive and negative predictive values for detecting or ruling out cartilage lesions were 96% and 78.9%. For labral lesions, the positive and negative predictive values were 97.5% and 80%. A high-resolution, 3D DESS technique with radial imaging at 3 T demonstrated high accuracy for detecting hip cartilage and labral lesions with excellent interobserver agreement and moderate correlation between MRI and intraoperative assessment. (orig.)

  9. Study on the interaction between albendazole and eosin Y by fluorescence, resonance Rayleigh scattering and frequency doubling scattering spectra and their analytical applications

    Science.gov (United States)

    Tian, Fengling; Huang, Wei; Yang, Jidong; Li, Qin

    In pH 3.25-3.35 Britton-Robinson (BR) buffer solution, albendazole (ABZ) could react with eosin Y (EY) to form a 1:1 ion-association complex, which not only results in the quenching of fluorescence, but also resulted in the great enhancement of resonance Rayleigh scattering (RRS) and frequency doubling scattering (FDS). Furthermore, a new RRS spectrum will appear, and the maximum RRS wavelength was located at about 356 nm. The detection limit for ABZ were 21.51 ng mL-1 for the fluorophotometry, 6.93 ng mL-1 for the RRS method and 12.89 ng mL-1 for the FDS method. Among them, the RRS method had the highest sensitivity. The experimental conditions were optimized and effects of coexisting substances were evaluated. Meanwhile, the influences of coexisting substances were tested. The methods have been successfully applied to the determination of ABZ in capsules and human urine samples. The composition and structure of the ion-association complex and the reaction mechanism were discussed.

  10. An analytical model for the determination of resonance frequencies of perforated beams

    International Nuclear Information System (INIS)

    Luschi, Luca; Pieri, Francesco

    2014-01-01

    In this paper, we develop closed expressions for the equivalent bending and shear stiffness of beams with regular square perforations, and apply them to the problem of determining the resonance frequencies of slender, regularly perforated clamped–clamped beams, which are of interest in the development of MEMS resonant devices. We prove that, depending on the perforation size, the Euler–Bernoulli equation or the more complex shear equation needs to be used to obtain accurate values for these frequencies. Extensive finite element method simulations are used to validate the proposed model over the full practical range of possible hole sizes. An experimental verification of the model is also presented. (paper)

  11. Expansion of lower-frequency locally resonant band gaps using a double-sided stubbed composite phononic crystals plate with composite stubs

    Energy Technology Data Exchange (ETDEWEB)

    Li, Suobin; Chen, Tianning [School of Mechanical Engineering and State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China); Wang, Xiaopeng, E-mail: xpwang@mail.xjtu.edu.cn [School of Mechanical Engineering and State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China); Li, Yinggang [Key Laboratory of High Performance Ship Technology of Ministry of Education, Wuhan University of Technology, Wuhan, 430070 (China); Chen, Weihua [School of Mechanical Engineering and State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China)

    2016-06-03

    We studied the expansion of locally resonant complete band gaps in two-dimensional phononic crystals (PCs) using a double-sided stubbed composite PC plate with composite stubs. Results show that the introduction of the proposed structure gives rise to a significant expansion of the relative bandwidth by a factor of 1.5 and decreases the opening location of the first complete band gap by a factor of 3 compared to the classic double-sided stubbed PC plate with composite stubs. Furthermore, more band gaps appear in the lower-frequency range (0.006). These phenomena can be attributed to the strong coupling between the “analogous rigid mode” of the stub and the anti-symmetric Lamb modes of the plate. The “analogous rigid mode” of the stub is produced by strengthening the localized resonance effect of the composite plates through the double-sided stubs, and is further strengthened through the introduction of composite stubs. The “analogous rigid mode” of the stubs expands the out-of-plane band gap, which overlaps with in-plane band gap in the lower-frequency range. As a result, the complete band gap is expanded and more complete band gaps appear. - Highlights: • Expansion of lower-frequency locally resonant BGs using novel composite phononic crystals plates. • The proposed structure expands the relative bandwidth 1.5 times compared to classic doubled-sided stubbed PC plates. • The opening location of the first complete BG decreases 3 times compared to the classic doubled-sided stubbed PC plates. • The concept “analogous rigid mode” is put forward to explain the expansion of lower-frequency BGs.

  12. Conformational cycle of the vitamin B12 ABC importer in liposomes detected by double electron-electron resonance (DEER).

    Science.gov (United States)

    Joseph, Benesh; Korkhov, Vladimir M; Yulikov, Maxim; Jeschke, Gunnar; Bordignon, Enrica

    2014-02-07

    Double electron-electron resonance is used here to investigate intermediates of the transport cycle of the Escherichia coli vitamin B12 ATP-binding cassette importer BtuCD-F. Previously, we showed the ATP-induced opening of the cytoplasmic gate I in TM5 helices, later confirmed by the AMP-PNP-bound BtuCD-F crystal structure. Here, other key residues are analyzed in TM10 helices (positions 307 and 322) and in the cytoplasmic gate II, i.e. the loop between TM2 and TM3 (positions 82 and 85). Without BtuF, binding of ATP induces detectable changes at positions 307 and 85 in BtuCD in liposomes. Together with BtuF, ATP triggers the closure of the cytoplasmic gate II in liposomes (reported by both positions 82 and 85). This forms a sealed cavity in the translocation channel in agreement with the AMP-PNP·BtuCD-F x-ray structure. When vitamin B12 and AMP-PNP are simultaneously present, the extent of complex formation is reduced, but the short 82-82 interspin distance detected indicates that the substrate does not affect the closed conformation of this gate. The existence of the BtuCD-F complex under these conditions is verified with spectroscopically orthogonal nitroxide and Gd(III)-based labels. The cytoplasmic gate II remains closed also in the vanadate-trapped state, but it reopens in the ADP-bound state of the complex. Therefore, we suggest that the substrate likely trapped in ATP·BtuCD-F can be released after ATP hydrolysis but before the occluded ADP-bound conformation is reached.

  13. Optimization of transversal relaxation of nitroxides for pulsed electron-electron double resonance spectroscopy in phospholipid membranes.

    Science.gov (United States)

    Dastvan, Reza; Bode, Bela E; Karuppiah, Muruga Poopathi Raja; Marko, Andriy; Lyubenova, Sevdalina; Schwalbe, Harald; Prisner, Thomas F

    2010-10-28

    Pulsed electron-electron double resonance (PELDOR) spectroscopy is increasingly applied to spin-labeled membrane proteins. However, after reconstitution into liposomes, spin labels often exhibit a much faster transversal relaxation (T(m)) than in detergent micelles, thus limiting application of the method in lipid bilayers. In this study, the main reasons for enhanced transversal relaxation in phospholipid membranes were investigated systematically by use of spin-labeled derivatives of stearic acid and phosphatidylcholine as well as spin-labeled derivatives of the channel-forming peptide gramicidin A under the conditions typically employed for PELDOR distance measurements. Our results clearly show that dephasing due to instantaneous diffusion that depends on dipolar interaction among electron spins is an important contributor to the fast echo decay in cases of high local concentrations of spin labels in membranes. The main difference between spin labels in detergent micelles and membranes is their local concentration. Consequently, avoiding spin clustering and suppressing instantaneous diffusion is the key step for maximizing PELDOR sensitivity in lipid membranes. Even though proton spin diffusion is an important relaxation mechanism, only in samples of low local concentrations does deuteration of acyl chains and buffer significantly prolong T(m). In these cases, values of up to 7 μs have been achieved. Furthermore, our study revealed that membrane composition and labeling position in the membrane can also affect T(m), either by promoting the segregation of spin-labeled species or by altering their exposure to matrix protons. Effects of other experimental parameters including temperature (<50 K), presence of oxygen, and cryoprotectant type are negligible under our experimental conditions.

  14. Effect of the upper-level decay on the resonantly enhanced four-wave mixing in a modified double-Λ system

    International Nuclear Information System (INIS)

    Kien, Fam Le; Hakuta, K.

    2004-01-01

    We study the continuous resonant four-wave mixing in a medium of atoms with a modified double-Λ level configuration. Under the far-off-resonance condition for a pair of levels, we reduce the five-level scheme to an effective three-level scheme, with a two-photon coupling between the two lower levels. We derive the exact steady-state solution to the density-matrix equations for the reduced scheme and obtain the wave-mixing equations for the fields in the continuous-wave regime. We show that the upper-level decay may substantially affect the resonantly enhanced wave-mixing process. We demonstrate that this decay shortens the conversion cycle rather than prolongs it

  15. Focus: Two-dimensional electron-electron double resonance and molecular motions: The challenge of higher frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Franck, John M.; Chandrasekaran, Siddarth; Dzikovski, Boris; Dunnam, Curt R.; Freed, Jack H., E-mail: jhf3@cornell.edu [Department of Chemistry and Chemical Biology and National Biomedical Center for Advanced ESR Technology, Cornell University, Ithaca, New York 14853 (United States)

    2015-06-07

    The development, applications, and current challenges of the pulsed ESR technique of two-dimensional Electron-Electron Double Resonance (2D ELDOR) are described. This is a three-pulse technique akin to 2D Exchange Nuclear Magnetic Resonance, but involving electron spins, usually in the form of spin-probes or spin-labels. As a result, it required the extension to much higher frequencies, i.e., microwaves, and much faster time scales, with π/2 pulses in the 2-3 ns range. It has proven very useful for studying molecular dynamics in complex fluids, and spectral results can be explained by fitting theoretical models (also described) that provide a detailed analysis of the molecular dynamics and structure. We discuss concepts that also appear in other forms of 2D spectroscopy but emphasize the unique advantages and difficulties that are intrinsic to ESR. Advantages include the ability to tune the resonance frequency, in order to probe different motional ranges, while challenges include the high ratio of the detection dead time vs. the relaxation times. We review several important 2D ELDOR studies of molecular dynamics. (1) The results from a spin probe dissolved in a liquid crystal are followed throughout the isotropic → nematic → liquid-like smectic → solid-like smectic → crystalline phases as the temperature is reduced and are interpreted in terms of the slowly relaxing local structure model. Here, the labeled molecule is undergoing overall motion in the macroscopically aligned sample, as well as responding to local site fluctuations. (2) Several examples involving model phospholipid membranes are provided, including the dynamic structural characterization of the boundary lipid that coats a transmembrane peptide dimer. Additionally, subtle differences can be elicited for the phospholipid membrane phases: liquid disordered, liquid ordered, and gel, and the subtle effects upon the membrane, of antigen cross-linking of receptors on the surface of plasma membrane

  16. Focus: Two-dimensional electron-electron double resonance and molecular motions: The challenge of higher frequencies

    International Nuclear Information System (INIS)

    Franck, John M.; Chandrasekaran, Siddarth; Dzikovski, Boris; Dunnam, Curt R.; Freed, Jack H.

    2015-01-01

    The development, applications, and current challenges of the pulsed ESR technique of two-dimensional Electron-Electron Double Resonance (2D ELDOR) are described. This is a three-pulse technique akin to 2D Exchange Nuclear Magnetic Resonance, but involving electron spins, usually in the form of spin-probes or spin-labels. As a result, it required the extension to much higher frequencies, i.e., microwaves, and much faster time scales, with π/2 pulses in the 2-3 ns range. It has proven very useful for studying molecular dynamics in complex fluids, and spectral results can be explained by fitting theoretical models (also described) that provide a detailed analysis of the molecular dynamics and structure. We discuss concepts that also appear in other forms of 2D spectroscopy but emphasize the unique advantages and difficulties that are intrinsic to ESR. Advantages include the ability to tune the resonance frequency, in order to probe different motional ranges, while challenges include the high ratio of the detection dead time vs. the relaxation times. We review several important 2D ELDOR studies of molecular dynamics. (1) The results from a spin probe dissolved in a liquid crystal are followed throughout the isotropic → nematic → liquid-like smectic → solid-like smectic → crystalline phases as the temperature is reduced and are interpreted in terms of the slowly relaxing local structure model. Here, the labeled molecule is undergoing overall motion in the macroscopically aligned sample, as well as responding to local site fluctuations. (2) Several examples involving model phospholipid membranes are provided, including the dynamic structural characterization of the boundary lipid that coats a transmembrane peptide dimer. Additionally, subtle differences can be elicited for the phospholipid membrane phases: liquid disordered, liquid ordered, and gel, and the subtle effects upon the membrane, of antigen cross-linking of receptors on the surface of plasma membrane

  17. A dual-wavelength overlapping resonance Rayleigh scattering method for the determination of chondroitin sulfate with nile blue sulfate

    Science.gov (United States)

    Cui, Zhiping; Hu, Xiaoli; Liu, Shaopu; Liu, Zhongfang

    2011-12-01

    A dual-wavelength overlapping resonance Rayleigh scattering (DWO-RRS) method was developed to detect chondroitin sulfate (CS) with nile blue sulfate (NBS). At pH 3.0-4.0 Britton-Robinson (BR) buffer medium, CS interacted with NBS to form an ion-association complex. As a result, the new spectra of resonance Rayleigh scattering (RRS), second order scattering (SOS) and frequence doubling scattering (FDS) appeared and their intensities were enhanced greatly. Their maximum wavelengths were located at 303 nm (RRS), 362 nm (RRS), 588 nm (SOS) and 350 nm (FDS), respectively. The scattering intensities of the three methods were proportional to the concentration of CS in certain ranges. The methods had high sensitivity and the detection limits were between 1.5 and 7.1 ng mL -1. The DWO-RRS method had the highest sensitivity with the detection limit being 1.5 ng mL -1. The characteristics of the spectra and optimal reaction conditions of RRS method were investigated. The effects of coexistent substances on the determination of CS were evaluated. Owing to the high sensitivity, RRS method had been applied to the determination of CS in eye drops with satisfactory results. The recovery range was between 99.4% and 104.6% and the relative standard deviation (RSD) was between 0.4% and 0.8%. In addition, the reasons for RRS enhancement were discussed and the shape of ion-association complex was characterized by atomic force microscopy (AFM).

  18. Determination of Double Bond Positions and Geometry of Methyl Linoleate Isomers with Dimethyl Disulfide Adducts by GC/MS.

    Science.gov (United States)

    Shibamoto, Shigeaki; Murata, Tasuku; Yamamoto, Kouhei

    2016-09-01

    The dimethyl disulfide (DMDS) adduct method is one of the convenient and effective methods for determining double bond positions of unsaturated fatty acid methyl esters (FAME) except conjugated FAME. When analyzed using gas chromatography/electron ionization-mass spectrometry (GC/EI-MS), unsaturated FAME with DMDS added to the double bonds yields high intensity MS spectra of characteristic ions. The MS spectra of characteristic ions can then be used to easily confirm double bond positions. Here we explore the GC/EI-MS analysis of the DMDS adducts of methyl linoleate geometrical isomers isolated by high performance liquid chromatography (HPLC) with a silver nitrate column. For C18:2-c9, c12 and C18:2-t9, t12, DMDS randomly formed adducts with double bonds at either carbon 9-10 or carbon 12-13, but not both at the same time due to steric hindrance. For C18:2-c9, t12 and C18:2-t9, c12, however, DMDS only formed adducts with the double bond in the cis configuration. Consequently, when analyzing fatty acids with methylene interrupted double bonds, with one double bond in the cis and one in the trans configuration, double bond positions cannot be completely confirmed.

  19. A novel strategy for NMR resonance assignment and protein structure determination

    International Nuclear Information System (INIS)

    Lemak, Alexander; Gutmanas, Aleksandras; Chitayat, Seth; Karra, Murthy; Farès, Christophe; Sunnerhagen, Maria; Arrowsmith, Cheryl H.

    2011-01-01

    The quality of protein structures determined by nuclear magnetic resonance (NMR) spectroscopy is contingent on the number and quality of experimentally-derived resonance assignments, distance and angular restraints. Two key features of protein NMR data have posed challenges for the routine and automated structure determination of small to medium sized proteins; (1) spectral resolution – especially of crowded nuclear Overhauser effect spectroscopy (NOESY) spectra, and (2) the reliance on a continuous network of weak scalar couplings as part of most common assignment protocols. In order to facilitate NMR structure determination, we developed a semi-automated strategy that utilizes non-uniform sampling (NUS) and multidimensional decomposition (MDD) for optimal data collection and processing of selected, high resolution multidimensional NMR experiments, combined it with an ABACUS protocol for sequential and side chain resonance assignments, and streamlined this procedure to execute structure and refinement calculations in CYANA and CNS, respectively. Two graphical user interfaces (GUIs) were developed to facilitate efficient analysis and compilation of the data and to guide automated structure determination. This integrated method was implemented and refined on over 30 high quality structures of proteins ranging from 5.5 to 16.5 kDa in size.

  20. Differential determination of 203Hg and 14C or 35S in double labelled biological samples

    International Nuclear Information System (INIS)

    Bem, E.M.; Bem, H.; Reimschussel, W.

    1979-01-01

    The differential determination of 203 Hg and 14 C or 35 S in double labelled biological samples is presented. The biological samples were mineralized with 70% HClO 4 and 30% H 2 O 2 in glass vials, MILLI-6. The γ-activity of 203 Hg was measured on a well scintillation counter. The total activity, due to 203 Hg and 14 C or 35 S, was measured by the liquid scintillation technique after addition of Aquasol into the same vials. The method of external standard channel ratio was used for standardization. Very good recoveries were obtained: 100+-0.7% for 203 Hg and 94.6-101.0% for 14 C and 35 S. This method could be used for other β, γ and β-active nuclides with similar β-spectra. (author)

  1. DETERMINATION OF ATTENUATION INDEX CURVE "Ri(f" FOR HOMOGENEOUS DOUBLE LOCKING ELEMENTS

    Directory of Open Access Journals (Sweden)

    BUZATU G. C.

    2016-12-01

    Full Text Available The paper is structured in three parts. In the first part of the paper, are presented some theoretical notions regarding the sound, noise, the sound insulations materials. Also in the first part of the paper are presented some characteristic regarding the insulation materials and there effects. In the second part it is described an calculation example for a homogeneous wall with double structure in order to determine the attenuation index curve "Ri(f". The example calculation contains 10 steps that must be followed and the final results are presented in table 7 and figure 3. The last part of the paper is represented by conclusions, where the authors tried to explain the importance of the curve "Ri(f" for reducing the noise in the buildings.

  2. Determination of the direction to a source of antineutrinos via inverse beta decay in Double Chooz

    Science.gov (United States)

    Nikitenko, Ya.

    2016-11-01

    To determine the direction to a source of neutrinos (and antineutrinos) is an important problem for the physics of supernovae and of the Earth. The direction to a source of antineutrinos can be estimated through the reaction of inverse beta decay. We show that the reactor neutrino experiment Double Chooz has unique capabilities to study antineutrino signal from point-like sources. Contemporary experimental data on antineutrino directionality is given. A rigorous mathematical approach for neutrino direction studies has been developed. Exact expressions for the precision of the simple mean estimator of neutrinos' direction for normal and exponential distributions for a finite sample and for the limiting case of many events have been obtained.

  3. Inter-spin distance determination using L-band (1-2 GHz) non-adiabatic rapid sweep electron paramagnetic resonance (NARS EPR)

    Science.gov (United States)

    Kittell, Aaron W.; Hustedt, Eric J.; Hyde, James S.

    2014-01-01

    Site-directed spin-labeling electron paramagnetic resonance (SDSL EPR) provides insight into the local structure and motion of a spin probe strategically attached to a molecule. When a second spin is introduced to the system, macromolecular information can be obtained through measurement of inter-spin distances either by continuous wave (CW) or pulsed electron double resonance (ELDOR) techniques. If both methodologies are considered, inter-spin distances of 8 to 80 Å can be experimentally determined. However, there exists a region at the upper limit of the conventional X-band (9.5 GHz) CW technique and the lower limit of the four-pulse double electron-electron resonance (DEER) experiment where neither method is particularly reliable. The work presented here utilizes L-band (1.9 GHz) in combination with non-adiabatic rapid sweep (NARS) EPR to address this opportunity by increasing the upper limit of the CW technique. Because L-band linewidths are three to seven times narrower than those at X-band, dipolar broadenings that are small relative to the X-band inhomogeneous linewidth become observable, but the signal loss due to the frequency dependence of the Boltzmann factor, has made L-band especially challenging. NARS has been shown to increase sensitivity by a factor of five, and overcomes much of this loss, making L-band distance determination more feasible [1]. Two different systems are presented and distances of 18–30 Å have been experimentally determined at physiologically relevant temperatures. Measurements are in excellent agreement with a helical model and values determined by DEER. PMID:22750251

  4. Determination of iodine in oyster tissue by isotope dilution laser resonance ionization mass spectrometry

    International Nuclear Information System (INIS)

    Fassett, J.D.; Murphy, T.J.

    1990-01-01

    The technique of laser resonance ionization mass spectrometry has been combined with isotope dilution analysis to determine iodine in oyster tissue. The long-lived radioisotope, 129I, was used to spike the samples. Samples were equilibrated with the 129I, wet ashed under controlled conditions, and iodine separated by coprecipitation with silver chloride. The analyte was dried as silver ammonium iodide upon a tantalum filament from which iodine was thermally desorbed in the resonance ionization mass spectrometry instrument. A single-color, two-photon resonant plus one-photon ionization scheme was used to form positive iodine ions. Long-lived iodine signals were achieved from 100 ng of iodine. The precision of 127I/129I measurement has been evaluated by replicate determinations of the spike, the spike calibration samples, and the oyster tissue samples and was 1.0%. Measurement precision among samples was 1.9% for the spike calibration and 1.4% for the oyster tissue. The concentration of iodine determined in SRM 1566a, Oyster Tissue, was 4.44 micrograms/g with an estimate of the overall uncertainty for the analysis of +/- 0.12 microgram/g

  5. Shear resonance mode decoupling to determine the characteristic matrix of piezoceramics for 3-D modeling.

    Science.gov (United States)

    Pardo, Lorena; García, Alvaro; de Espinosa, Francisco Montero; Brebøl, Klaus

    2011-03-01

    The determination of the characteristic frequencies of an electromechanical resonance does not provide enough data to obtain the material properties of piezoceramics, including all losses, from complex impedance measurements. Values of impedance around resonance and antiresonance frequencies are also required to calculate the material losses. Uncoupled resonances are needed for this purpose. The shear plates used for the material characterization present unavoidable mode coupling of the shear mode and other modes of the plate. A study of the evolution of the complex material coefficients as the coupling of modes evolves with the change in the aspect ratio (lateral dimension/thickness) of the plate is presented here. These are obtained using software. A soft commercial PZT ceramic was used in this study and several shear plates amenable to material characterization were obtained in the range of aspect ratios below 15. The validity of the material properties for 3-D modeling of piezoceramics is assessed by means of finite element analysis, which shows that uncoupled resonances are virtually pure thickness-driven shear modes.

  6. Study on the ternary mixed ligand complex of palladium(II)-aminophylline-fluorescein sodium by resonance Rayleigh scattering, second-order scattering and frequency doubling scattering spectrum and its analytical application.

    Science.gov (United States)

    Chen, Peili; Liu, Shaopu; Liu, Zhongfang; Hu, Xiaoli

    2011-01-01

    The interaction between palladium(II)-aminophylline and fluorescein sodium was investigated by resonance Rayleigh scattering, second-order scattering and frequency doubling scattering spectrum. In pH 4.4 Britton-Robinson (BR) buffer medium, aminophylline (Ami) reacted with palladium(II) to form chelate cation([Pd(Ami)]2+), which further reacted with fluorescein sodium (FS) to form ternary mixed ligand complex [Pd(Ami)(FS)2]. As a result, resonance Rayleigh scattering (RRS), second-order scattering (SOS) and frequency doubling scattering spectrum (FDS) were enhanced. The maximum scattering wavelengths of [Pd(Ami)(FS)2] were located at 300 nm (RRS), 650 nm (SOS) and 304 nm (FDS). The scattering intensities were proportional to the Ami concentration in a certain range and the detection limits were 7.3 ng mL(-1) (RRS), 32.9 ng mL(-1) (SOS) and 79.1 ng mL(-1) (FDS), respectively. Based on it, the new simple, rapid, and sensitive scattering methods have been proposed to determine Ami in urine and serum samples. Moreover, the formation mechanism of [Pd(Ami)(FS)2] and the reasons for enhancement of RRS were fully discussed. Crown Copyright © 2010. Published by Elsevier B.V. All rights reserved.

  7. Electron density distribution in BaPb1−xSbxO3 superconducting oxides studied by double nuclear magnetic resonance methods

    International Nuclear Information System (INIS)

    Piskunov, Yu. V.; Ogloblichev, V. V.; Arapova, I. Yu.; Sadykov, A. V.; Gerashchenko, A. P.; Verkhovskii, S. V.

    2011-01-01

    The effect of charge disorder on the formation of an inhomogeneous state of the electron system in the conduction band in BaPb 1−x Sb x O 3 superconducting oxides is investigated experimentally by NMR methods. The NMR spectra of 17 O are measured systematically, and the contributions from 17 O atoms with different cation nearest surroundings are identified. It is found that microscopic regions with an elevated spin density of charge carriers are formed within two coordination spheres near antimony ions. Nuclei of the superconducting phase of the oxide (regions with an elevated antimony concentration) microscopically distributed over the sample are detected in compounds with x = 0.25 and 0.33. Experiments in which a double resonance signal of the spin echo of 17 O- 207 Pb and 17 O- 121 Sb are measured in the metal phase of BaPb 1−x Sb x O 3 oxides are carried out for the first time. The constants of indirect heteronuclear spin-spin 17 O- 207 Pb interaction are determined as functions of the local Knight shift 207 Ks. The estimates of the constants of the indirect interaction between the nuclei of the nearest neighbors (O-Pb and Pb-Pb atoms) and analysis of evolution of the NMR spectra of 17 O upon a change in the antimony concentration are convincing evidence in favor of the development of a microscopically inhomogeneous state of the electron system in the metal phase of BaPb 1−x Sb x O 3 oxides.

  8. Determination of vitamin B12 (cobalamine) absorption by means of a simple double-isotope technique

    International Nuclear Information System (INIS)

    Hippe, E.; Brynskov, J.; Gimsing, P.; Hjelt, K.

    1986-01-01

    The background, practical instruction and clinical results of a simplified method of determining the absorption of cobalamine (vitamin B 12 ) are presented. The simultaneous administration of 57 CO-CN-cobalamine, a non-absorbable marker ( 51 CrCl 3 ), and red carmine tablets enable quantitative assessments of the cobalamine absorption by collection of a small red feaces sample. In contrast to the classical Schilling-test, this vitamin B 12 absorption test (B 12 -ABS-test) or faeces-spot-test is, independent of fasting, flushing dose, renal function and diurnal urinary collection. This is documented in a series of clinical studies. The B 12 -ABS-test provides accurate and precise results compared to the reference method (whole-body-counting). The Schilling test, on the contrary, gives approximately 50% false low values in a reference group of elderly hospitalized patients. A modification of the B 12 -ABS-test, has been used to determine the cobalamine absorption in children, and a set of age-related reference intervals have been established, together with quantitative measurements of the cobalamine absorption in children with small bowel diseases. Based on several years of practical experience, we recommend replacement of the Schilling test by this simple double-isotope technique. (author)

  9. Point-of-care ultrasound versus auscultation in determining the position of double-lumen tube.

    Science.gov (United States)

    Hu, Wei-Cai; Xu, Lei; Zhang, Quan; Wei, Li; Zhang, Wei

    2018-03-01

    This study was designed to assess the accuracy of point-of-care ultrasound in determining the position of double-lumen tubes (DLTs).A total of 103 patients who required DLT intubation were enrolled into the study. After DLTs were tracheal intubated in the supine position, an auscultation researcher and ultrasound researcher were sequentially invited in the operating room to conduct their evaluation of the DLT. After the end of their evaluation, fiberscope researchers (FRs) were invited in the operating room to evaluate the position of DLT using a fiberscope. After the patients were changed to the lateral position, the same evaluation process was repeated. These 3 researchers were blind to each other when they made their conclusions. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were obtained by statistical analysis.When left DLTs (LDLTs) were used, the accuracy of ultrasound (84.2% [72.1%, 92.5%]) was higher than the accuracy of auscultation (59.7% [45.8%, 72.4%]) (P auscultation (67.4% [52.0%, 80.5%]) (P auscultation (54.4% [40.7%, 67.6%]) (P auscultation (47.8% [32.9%, 63.1%]) (P auscultation in determining the position of DLTs.

  10. Determination of permittivity of pulses and cereals using metamaterial split ring resonator

    Science.gov (United States)

    Chakyar, Sreedevi P.; Sikha Simon, K.; Murali, Aathira; Shanto T., A.; Andrews, Jolly; Joseph V., P.

    2017-06-01

    Relative permittivity of wide variety of pulses and cereals are precisely determined with the help of metamaterial Split Ring Resonator (SRR) operating at microwave frequencies using a simple extraction procedure. The unknown permittivity of food samples in powder form are evaluated from a calibration curve drawn between the dielectric constant of some standard samples and LC resonant frequency of SRR test probe with the sample placed over it. The experimental setup consists of SRR test probe arranged between transmitting and receiving probes connected to a vector network analyzer. Unknown relative permittivity of the sample is obtained by placing it on the SRR surface and is evaluated from the calibration curve which is found to be in good agreement with the expected standard values. The possible applications of this sensitive and easy technique are analyzed in the field of food preservation, quality checking, adulteration etc.

  11. Surface magnetic anisotropy in glass-coated amorphous microwires as determined from ferromagnetic resonance measurements

    International Nuclear Information System (INIS)

    Garcia-Miquel, H.; Garcia, J.M.; Garcia-Beneytez, J.M.; Vazquez, M.

    2001-01-01

    The ferromagnetic resonance frequency of different Co base glass-coated amorphous magnetic microwires about 3.5 μm in diameter with negative, vanishing and positive magnetostriction has been investigated from power absorption measurements in the microwave frequency range. The experimental technique employed here involves the replacement of the dielectric of a coaxial transmission line by the sample to be measured. From the evolution of the resonance frequency with DC applied magnetic field, the surface magnetic anisotropy field of the microwires has been quantitatively obtained and, as expected, found to depend on the sign and strength of the magnetostriction. Similar values for the surface anisotropy are obtained in comparison with bulk anisotropy as determined from quasi-static hysteresis loops measurements

  12. Determination of ultra-low levels of uranium using resonance ionization mass spectrometry

    International Nuclear Information System (INIS)

    Kiran Kumar, P.V.; Acharyulu, G.V.S.G.

    2015-01-01

    The determination of isotopic composition of actinides like U and Pu is important, due to their distribution in the environment as a result of nuclear weapons testing, fuel reprocessing, reactor operations and to a smaller extent from accidental releases. The analytical methods like fission track analysis (FTA), thermal ionization mass spectrometry (TIMS), inductively coupled plasma mass spectrometry (ICPMS) and resonance ionization mass spectrometry (RIMS) have evolved as sensitive techniques. Resonance Ionization Mass Spectrometry yields rapid isotopic signature data for material containing actinides without requiring time-consuming sample preparation and chemical separation procedures. In this paper, authors presented the details of the methodology and results for low-level detection of uranium using RIMS

  13. RESONANCE

    Indian Academy of Sciences (India)

    Teaching and Learning 'Genetics with Drosophila. 3. Pattern of Inheritance of Autosome and Sex . Chromosome Linked Genes/Characters. Phenotypic characters or traits are determined by genes, and genes are physically located on different chromosomes. This is the basic tenet of the chromosomal theory of inheritance.

  14. RESONANCE

    Indian Academy of Sciences (India)

    To the extent that genes influence our behaviour it may well be that our ... other by a coefficient of genetic relatedness r of 0.75 but a female. Figure 1. ... cal and empirical work. ... rather famous one is called PSR, for paternally transmitted sex ... Life cycle of ... Genic balance sex determination (GBSD): According to this model ...

  15. Biomechanical and magnetic resonance imaging evaluation of a single- and double-row rotator cuff repair in an in vivo sheep model.

    Science.gov (United States)

    Baums, Mike H; Spahn, Gunter; Buchhorn, Gottfried H; Schultz, Wolfgang; Hofmann, Lars; Klinger, Hans-Michael

    2012-06-01

    To investigate the biomechanical and magnetic resonance imaging (MRI)-derived morphologic changes between single- and double-row rotator cuff repair at different time points after fixation. Eighteen mature female sheep were randomly assigned to either a single-row treatment group using arthroscopic Mason-Allen stitches or a double-row treatment group using a combination of arthroscopic Mason-Allen and mattress stitches. Each group was analyzed at 1 of 3 survival points (6 weeks, 12 weeks, and 26 weeks). We evaluated the integrity of the cuff repair using MRI and biomechanical properties using a mechanical testing machine. The mean load to failure was significantly higher in the double-row group compared with the single-row group at 6 and 12 weeks (P = .018 and P = .002, respectively). At 26 weeks, the differences were not statistically significant (P = .080). However, the double-row group achieved a mean load to failure similar to that of a healthy infraspinatus tendon, whereas the single-row group reached only 70% of the load of a healthy infraspinatus tendon. No significant morphologic differences were observed based on the MRI results. This study confirms that in an acute repair model, double-row repair may enhance the speed of mechanical recovery of the tendon-bone complex when compared with single-row repair in the early postoperative period. Double-row rotator cuff repair enables higher mechanical strength that is especially sustained during the early recovery period and may therefore improve clinical outcome. Crown Copyright © 2012. Published by Elsevier Inc. All rights reserved.

  16. Stark effect investigations of excited cadmium, ytterbium, and thulium I-levels using the methods of double resonance and level crossing

    International Nuclear Information System (INIS)

    Rinkleff, R.H.

    1977-01-01

    Using the method of optical double resonance, the 5s5p 3 P 1 level tensor polarizability of Cadmium has been measured. For this state, various authors have published different results, using different experimental methods. The experimental result presented here is in excellent agreement with the value of Happer, based on level crossing investigations, and agrees well with the theoretical result of Robinson based on a modified Sternheimer approximation, and so gives a reliable value for the tensor polarizability. Furthermore the tensor polarizability of the 6s6p 3 P 1 - level of the even Ytterbium isotopes and the odd Ytterbium 171 nucleus have been measured with the optical double resonance method, and the Stark constant has been calculated based on a given theory and oscillator strengths. Using the methods of optical double resonance and level crossing, the tensor polarizability of 5 excited levels of the Thulium configurations 4f 13 6s6p + 4f 12 5d6s 2 have been measured. From the experimental Stark constants and the angular coefficients of the eigenfunctions calculated by Camus, the radial integrals I(5d, 5p) and I(6p, 5d) are calculated for electric dipole transitions between levels of the configurations 4f 12 5d6s 2 + 4f 13 6s6p and levels of the 4f 12 6p6s 2 + 4f 13 6s5d configurations. The tensor polarizability calculated with these radial integrals show very good agreement with the experimental values. (orig./LH) [de

  17. Double-labeled donor probe can enhance the signal of fluorescence resonance energy transfer (FRET) in detection of nucleic acid hybridization

    Science.gov (United States)

    Okamura, Yukio; Kondo, Satoshi; Sase, Ichiro; Suga, Takayuki; Mise, Kazuyuki; Furusawa, Iwao; Kawakami, Shigeki; Watanabe, Yuichiro

    2000-01-01

    A set of fluorescently-labeled DNA probes that hybridize with the target RNA and produce fluorescence resonance energy transfer (FRET) signals can be utilized for the detection of specific RNA. We have developed probe sets to detect and discriminate single-strand RNA molecules of plant viral genome, and sought a method to improve the FRET signals to handle in vivo applications. Consequently, we found that a double-labeled donor probe labeled with Bodipy dye yielded a remarkable increase in fluorescence intensity compared to a single-labeled donor probe used in an ordinary FRET. This double-labeled donor system can be easily applied to improve various FRET probes since the dependence upon sequence and label position in enhancement is not as strict. Furthermore this method could be applied to other nucleic acid substances, such as oligo RNA and phosphorothioate oligonucleotides (S-oligos) to enhance FRET signal. Although the double-labeled donor probes labeled with a variety of fluorophores had unexpected properties (strange UV-visible absorption spectra, decrease of intensity and decay of donor fluorescence) compared with single-labeled ones, they had no relation to FRET enhancement. This signal amplification mechanism cannot be explained simply based on our current results and knowledge of FRET. Yet it is possible to utilize this double-labeled donor system in various applications of FRET as a simple signal-enhancement method. PMID:11121494

  18. Stark resonances: asymptotics and distributional Borel sum

    International Nuclear Information System (INIS)

    Caliceti, E.; Grecchi, V.; Maioli, M.

    1993-01-01

    We prove that the Stark effect perturbation theory of a class of bound states uniquely determines the position and the width of the resonances by Distributional Borel Sum. In particular the small field asymptotics of the width is uniquely related to the large order asymptotics of the perturbation coefficients. Similar results apply to all the ''resonances'' of the anharmonic and double well oscillators. (orig.)

  19. The direct determination of double bond positions in lipid mixtures by liquid chromatography/in-line ozonolysis/mass spectrometry

    International Nuclear Information System (INIS)

    Sun, Chenxing; Zhao, Yuan-Yuan; Curtis, Jonathan M.

    2013-01-01

    Highlights: ► An ozonolysis reactor was coupled in-line with mass spectrometry (O 3 -MS). ► Double bond positions in FAME were determined unambiguously without standards. ► LC directly connected to O 3 -MS allowed double bond localization in lipid mixtures. ► LC/O 3 -MS applied to bovine fat demonstrated practical use in lipid analysis. -- Abstract: The direct determination of double bond positions in unsaturated lipids using in-line ozonolysis-mass spectrometry (O 3 -MS) is described. In this experiment, ozone penetrates through the semi-permeable Teflon AF-2400 tubing containing a flow of a solution of fatty acid methyl esters (FAME). Unsaturated FAME are thus oxidized by the ozone and cleaved at the double bond positions. The ozonolysis products then flow directly into the atmospheric pressure photoionization (APPI) source of a mass spectrometer for analysis. Aldehyde products retaining the methyl ester group are indicative of the double bond positions in unsaturated FAME. For the first time, O 3 -MS is able to couple directly to high performance liquid chromatography (HPLC), making the double bond localization in lipid mixtures possible. The application of LC/O 3 -MS has been demonstrated for a fat sample from bovine adipose tissue. A total of 9 unsaturated FAME including 6 positional isomers were identified unambiguously, without comparison to standards. The in-line ozonolysis reaction apparatus is applicable to most mass spectrometers without instrumental modification; it is also directly compatible with various LC columns. The LC/O 3 -MS method described here is thus a practical, versatile and easy to use new approach to the direct determination of double bond positions in lipids, even in complex mixtures

  20. The direct determination of double bond positions in lipid mixtures by liquid chromatography/in-line ozonolysis/mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Chenxing; Zhao, Yuan-Yuan [Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5 (Canada); Curtis, Jonathan M., E-mail: jcurtis1@ualberta.ca [Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5 (Canada)

    2013-01-31

    Highlights: ► An ozonolysis reactor was coupled in-line with mass spectrometry (O{sub 3}-MS). ► Double bond positions in FAME were determined unambiguously without standards. ► LC directly connected to O{sub 3}-MS allowed double bond localization in lipid mixtures. ► LC/O{sub 3}-MS applied to bovine fat demonstrated practical use in lipid analysis. -- Abstract: The direct determination of double bond positions in unsaturated lipids using in-line ozonolysis-mass spectrometry (O{sub 3}-MS) is described. In this experiment, ozone penetrates through the semi-permeable Teflon AF-2400 tubing containing a flow of a solution of fatty acid methyl esters (FAME). Unsaturated FAME are thus oxidized by the ozone and cleaved at the double bond positions. The ozonolysis products then flow directly into the atmospheric pressure photoionization (APPI) source of a mass spectrometer for analysis. Aldehyde products retaining the methyl ester group are indicative of the double bond positions in unsaturated FAME. For the first time, O{sub 3}-MS is able to couple directly to high performance liquid chromatography (HPLC), making the double bond localization in lipid mixtures possible. The application of LC/O{sub 3}-MS has been demonstrated for a fat sample from bovine adipose tissue. A total of 9 unsaturated FAME including 6 positional isomers were identified unambiguously, without comparison to standards. The in-line ozonolysis reaction apparatus is applicable to most mass spectrometers without instrumental modification; it is also directly compatible with various LC columns. The LC/O{sub 3}-MS method described here is thus a practical, versatile and easy to use new approach to the direct determination of double bond positions in lipids, even in complex mixtures.

  1. Hyperfine structure of the X 2Σ+ ground state of Ca 35Cl and Ca 37Cl by molecular-beam, laser-rf double resonance

    International Nuclear Information System (INIS)

    Childs, W.J.; Cok, D.R.; Goodman, L.S.

    1982-01-01

    The hyperfine structure of the X 2 Σ + state of Ca 35 Cl and Ca 37 Cl, unresolved in previous studies, has been investigated in detail by the molecular-beam, laser-rf, double-resonance technique. Results for the spin-rotation interaction and the dipole and quadrupole hfs constants are given in the form of Dunham coefficients so that the N'' and v'' dependence of each constant can be explicitly exhibited. The results, after dividing out the purely nuclear effects, fall between the corresponding values for CaF and CaBr, as expected

  2. Determination of elastic modulus for hollow spherical shells via resonant ultrasound spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Xiaojun [Institute of Modern Physics, Fudan University, Shanghai 200433 (China); Research Center of Laser Fusion, CAEP, Mianyang 621900 (China); Tang, Xing; Wang, Zongwei [Research Center of Laser Fusion, CAEP, Mianyang 621900 (China); Chen, Qian; Qian, Menglu [Institute of Acoustic, Tongji University, Shanghai 200092 (China); Meng, Jie [Research Center of Laser Fusion, CAEP, Mianyang 621900 (China); Tang, Yongjian [Institute of Modern Physics, Fudan University, Shanghai 200433 (China); Research Center of Laser Fusion, CAEP, Mianyang 621900 (China); Shen, Hao [Institute of Modern Physics, Fudan University, Shanghai 200433 (China); Gao, Dangzhong, E-mail: dgaocn@163.com [Research Center of Laser Fusion, CAEP, Mianyang 621900 (China)

    2017-04-15

    Highlights: • The axisymmetric frequency equation of an isotropic hollow two-layer sphere is deduced by three dimension elasticity theory and global matrix method. • The simulated results demonstrate that the natural frequencies of a hollow sphere are more strongly dependent on Young’s modulus than Poisson's ratio. • The Young’s moduli of polymer capsules with an sub-millimeter inner radius are measured accurately with an uncertainty of ∼10%. - Abstract: The elastic property of a capsule is one of the essential parameters both in engineering applications and scientific understanding of material nature in inertial confinement fusion (ICF) experiments. The axisymmetric frequency equation of an isotropic hollow two-layer sphere is deduced by three dimension elasticity theory and global matrix method, and a combined resonant ultrasound spectroscopy(RUS), which consists of a piezoelectric-based resonant ultrasound spectroscopy(PZT-RUS) and a laser-based resonant ultrasound spectroscopy(LRUS), is developed for determining the elastic modulus of capsule. To understand the behavior of natural frequencies varying with elastic properties, the dependence of natural frequencies on Young’s modulus and Poisson’s ratio are calculated numerically. Some representative polymer capsules are measured using PZT-RUS and LRUS. Based on the theoretical and experimental results, the Young’s moduli of these capsules are measured accurately with an uncertainty of ∼10%.

  3. Determination of Porosity in Shale by Double Headspace Extraction GC Analysis.

    Science.gov (United States)

    Zhang, Chun-Yun; Li, Teng-Fei; Chai, Xin-Sheng; Xiao, Xian-Ming; Barnes, Donald

    2015-11-03

    This paper reports on a novel method for the rapid determination of the shale porosity by double headspace extraction gas chromatography (DHE-GC). Ground core samples of shale were placed into headspace vials and DHE-GC measurements of released methane gas were performed at a given time interval. A linear correlation between shale porosity and the ratio of consecutive GC signals was established both theoretically and experimentally by comparing with the results from the standard helium pycnometry method. The results showed that (a) the porosity of ground core samples of shale can be measured within 30 min; (b) the new method is not significantly affected by particle size of the sample; (c) the uncertainties of measured porosities of nine shale samples by the present method range from 0.31 to 0.46 p.u.; and (d) the results obtained by the DHE-GC method are in a good agreement with those from the standard helium pycnometry method. In short, the new DHE-GC method is simple, rapid, and accurate, making it a valuable tool for shale gas-related research and applications.

  4. Radiation dose determines the method for quantification of DNA double strand breaks

    International Nuclear Information System (INIS)

    Bulat, Tanja; Keta, Olitija; Korićanac, Lela; Žakula, Jelena; Petrović, Ivan; Ristić-Fira, Aleksandra; Todorović, Danijela

    2016-01-01

    Ionizing radiation induces DNA double strand breaks (DSBs) that trigger phosphorylation of the histone protein H2AX (γH2AX). Immunofluorescent staining visualizes formation of γH2AX foci, allowing their quantification. This method, as opposed to Western blot assay and Flow cytometry, provides more accurate analysis, by showing exact position and intensity of fluorescent signal in each single cell. In practice there are problems in quantification of γH2AX. This paper is based on two issues: the determination of which technique should be applied concerning the radiation dose, and how to analyze fluorescent microscopy images obtained by different microscopes. HTB140 melanoma cells were exposed to γ-rays, in the dose range from 1 to 16 Gy. Radiation effects on the DNA level were analyzed at different time intervals after irradiation by Western blot analysis and immunofluorescence microscopy. Immunochemically stained cells were visualized with two types of microscopes: AxioVision (Zeiss, Germany) microscope, comprising an ApoTome software, and AxioImagerA1 microscope (Zeiss, Germany). Obtained results show that the level of γH2AX is time and dose dependent. Immunofluorescence microscopy provided better detection of DSBs for lower irradiation doses, while Western blot analysis was more reliable for higher irradiation doses. AxioVision microscope containing ApoTome software was more suitable for the detection of γH2AX foci. (author)

  5. Determining if pretreatment PSA doubling time predicts PSA trajectories after radiation therapy for localized prostate cancer

    International Nuclear Information System (INIS)

    Soto, Daniel E.; Andridge, Rebecca R.; Pan, Charlie C.; Williams, Scott G.; Taylor, Jeremy M.G.; Sandler, Howard M.

    2009-01-01

    Introduction: To determine if pretreatment PSA doubling time (PSA-DT) can predict post-radiation therapy (RT) PSA trajectories for localized prostate cancer. Materials and methods: Three hundred and seventy-five prostate cancer patients treated with external beam RT without androgen deprivation therapy (ADT) were identified with an adequate number of PSA values. We utilized a linear mixed model (LMM) analysis to model longitudinal PSA data sets after definitive treatment. Post-treatment PSA trajectories were allowed to depend on the pre-RT PSA-DT, pre-RT PSA (iPSA), Gleason score (GS), and T-stage. Results: Pre-RT PSA-DT had a borderline impact on predicting the rate of PSA rise after nadir (p = 0.08). For a typical low risk patient (T1, GS ≤ 6, iPSA 10), the predicted PSA-DT post-nadir was 21% shorter for pre-RT PSA-DT 24 month (19 month vs. 24 month). Additional significant predictors of post-RT PSA rate of rise included GS (p < 0.0001), iPSA (p < 0.0001), and T-stage (p = 0.02). Conclusions: We observed a trend between rapidly rising pre-RT PSA and the post-RT post-nadir PSA rise. This effect appeared to be independent of iPSA, GS, or T-stage. The results presented suggest that pretreatment PSA-DT may help predict post-RT PSA trajectories

  6. Radiation dose determines the method for quantification of DNA double strand breaks

    Energy Technology Data Exchange (ETDEWEB)

    Bulat, Tanja; Keta, Olitija; Korićanac, Lela; Žakula, Jelena; Petrović, Ivan; Ristić-Fira, Aleksandra [University of Belgrade, Vinča Institute of Nuclear Sciences, Belgrade (Serbia); Todorović, Danijela, E-mail: dtodorovic@medf.kg.ac.rs [University of Kragujevac, Faculty of Medical Sciences, Kragujevac (Serbia)

    2016-03-15

    Ionizing radiation induces DNA double strand breaks (DSBs) that trigger phosphorylation of the histone protein H2AX (γH2AX). Immunofluorescent staining visualizes formation of γH2AX foci, allowing their quantification. This method, as opposed to Western blot assay and Flow cytometry, provides more accurate analysis, by showing exact position and intensity of fluorescent signal in each single cell. In practice there are problems in quantification of γH2AX. This paper is based on two issues: the determination of which technique should be applied concerning the radiation dose, and how to analyze fluorescent microscopy images obtained by different microscopes. HTB140 melanoma cells were exposed to γ-rays, in the dose range from 1 to 16 Gy. Radiation effects on the DNA level were analyzed at different time intervals after irradiation by Western blot analysis and immunofluorescence microscopy. Immunochemically stained cells were visualized with two types of microscopes: AxioVision (Zeiss, Germany) microscope, comprising an ApoTome software, and AxioImagerA1 microscope (Zeiss, Germany). Obtained results show that the level of γH2AX is time and dose dependent. Immunofluorescence microscopy provided better detection of DSBs for lower irradiation doses, while Western blot analysis was more reliable for higher irradiation doses. AxioVision microscope containing ApoTome software was more suitable for the detection of γH2AX foci. (author)

  7. Broader energy distribution of CO adsorbed at polycrystalline Pt electrode in comparison with that at Pt(111) electrode in H_2SO_4 solution confirmed by potential dependent IR/visible double resonance sum frequency generation spectroscopy

    International Nuclear Information System (INIS)

    Yang, Shuo; Noguchi, Hidenori; Uosaki, Kohei

    2017-01-01

    Highlights: • Electrochemical SFG spectroscopy is an efficient in situ probe of electronic structure at electrochemical interface. • Electrooxidation performances of CO adsorbed on polycrystalline Pt and Pt(111) electrodes were compared. • The enhanced SFG signal of CO on Pt electrodes was observed due to a vibrational-electronic double resonance effect. • The broader energy distribution of 5sa state of CO on polycrystalline Pt than on Pt(111) is proved by SFG results. - Abstract: Electrochemical cyclic voltammetry and potential dependent double resonance sum frequency generation (DR-SFG) spectroscopy were performed on CO adsorbed on polycrystalline Pt and Pt(111) electrodes in H_2SO_4 solution to examine the effect of substrate on the electronic structure of CO. The dependence of SFG intensity on potential and visible energy for atop CO band was observed on both polycrystalline and single crystalline Pt electrodes. Enhancement of the SFG intensity was determined to be a direct result of a surface electronic resonance of the visible/SF light with the electronic transition from Fermi level of Pt to the 5σ_a anti-bonding state of adsorbed CO, in agreement with previous results. Interestingly, when compared to the Pt(111) electrode, the distribution width of the intensity enhancement region on polycrystalline Pt is broader than on Pt(111). This suggests that the energy distribution of the 5σ_a state of CO on polycrystalline Pt surface is broader than that on Pt(111) due to the complex surface structure of the polycrystalline Pt electrode.

  8. Magnesium isotope compositions of Solar System materials determined by double spiking

    Science.gov (United States)

    Hin, R.; Lai, Y. J.; Coath, C.; Elliott, T.

    2015-12-01

    As a major element, magnesium is of interest for investigating large scale processes governing the formation and evolution of rocky planetary bodies. Determining the Mg isotope composition of the Earth and other planetary bodies has hence been a topic of interest ever since mass-dependent fractionation of 'non-traditional' stable isotopes has been used to study high-temperature processes. Published results, however, suffer from disagreement on the Mg isotope compositions of the Earth and chondrites [1-5], which is attributed to residual matrix effects. Nonetheless, most recent studied have converged towards a homogeneous (chondritic) Mg isotope composition in the Solar System [2-5]. However, in several of the recent studies there is a hint of a systematic difference of about 0.02-0.06‰ in the 26Mg/24Mg isotope compositions of chondrites and Earth. Such difference, however, is only resolvable by taking standard errors, which assumes robust data for homogenous sample sets. The discrepancies between various studies unfortunately undermine the confidence in such robustness and homogeneity. The issues with matrix effects during isotopic analyses can be overcome by using a double spike approach. Such methodology generally requires three isotope ratios to solve for three unknowns, a requirement that cannot be met for Mg. However, using a newly developed approach, we present Mg isotope compositions obtained by critical mixture double spiking. This new approach should allow greater confidence in the robustness of the data and hence enable improvement of. Preliminary data indicate that chondrites have a resolvable ~0.04‰ lighter 26Mg/24Mg than (ultra)mafic rocks from Earth, Mars and the eucrite parent body, which appear indistinguishable from each other. It seems implausible that this difference is caused by magmatic process such as partial melting or crystallisation. More likely, Mg isotopes are fractionated by a non-magmatic process during the formation of planets, e

  9. The double burden of malnutrition in Indonesia: Social determinants and geographical variations.

    Science.gov (United States)

    Hanandita, Wulung; Tampubolon, Gindo

    2015-12-01

    The presence of simultaneous under- and over-nutrition has been widely documented in low- and middle-income countries, but global nutritional research has seen only a few large-scale population studies from Indonesia. We investigate the social determinants as well as the geographical variations of under- and over-nutrition in Indonesia using the largest public health study ever conducted in the country, the National Basic Health Research 2007 (N=645,032). Multilevel multinomial logistic regression and quantile regression models are fitted to estimate the association between nutritional status and a number of socio-economic indicators at both the individual and district levels. We find that: (1) education and income reduce the odds of being underweight by 10-30% but at the same time increase those of overweight by 10-40%; (2) independent from the compositional effect of poverty, income inequality is detrimental to population health: a 0.1 increase in the Gini coefficient is associated with an 8-12% increase in the odds of an individual׳s being both under- and overweight; and (3) the effects that these determinants have upon nutritional status are not necessarily homogeneous along the continuum of body mass index. Equally important, our analysis reveals that there is substantial spatial clustering of areas with elevated risk of under- or over-nutrition across the 17,000-island archipelago. As of 2007, under-nutrition in Indonesia remains a 'disease of poverty', while over-nutrition is one of affluence. The income inequality accompanying Indonesia׳s economic growth may aggravate the dual burden of under- and over-nutrition. A more equitable economic policy and a policy that improves living standards may be effective for addressing the double burden.

  10. The double burden of malnutrition in Indonesia: Social determinants and geographical variations

    Directory of Open Access Journals (Sweden)

    Wulung Hanandita

    2015-12-01

    Full Text Available The presence of simultaneous under- and over-nutrition has been widely documented in low- and middle-income countries, but global nutritional research has seen only a few large-scale population studies from Indonesia. We investigate the social determinants as well as the geographical variations of under- and over-nutrition in Indonesia using the largest public health study ever conducted in the country, the National Basic Health Research 2007 (N=645,032. Multilevel multinomial logistic regression and quantile regression models are fitted to estimate the association between nutritional status and a number of socio-economic indicators at both the individual and district levels. We find that: (1 education and income reduce the odds of being underweight by 10–30% but at the same time increase those of overweight by 10–40%; (2 independent from the compositional effect of poverty, income inequality is detrimental to population health: a 0.1 increase in the Gini coefficient is associated with an 8–12% increase in the odds of an individual׳s being both under- and overweight; and (3 the effects that these determinants have upon nutritional status are not necessarily homogeneous along the continuum of body mass index. Equally important, our analysis reveals that there is substantial spatial clustering of areas with elevated risk of under- or over-nutrition across the 17,000-island archipelago. As of 2007, under-nutrition in Indonesia remains a ‘disease of poverty’, while over-nutrition is one of affluence. The income inequality accompanying Indonesia׳s economic growth may aggravate the dual burden of under- and over-nutrition. A more equitable economic policy and a policy that improves living standards may be effective for addressing the double burden.

  11. Sequence determination and resonance assignments of an Azomonas siderophore using 13C natural abundance 13C-1H HNCA experiment

    Czech Academy of Sciences Publication Activity Database

    Wasielewski, E.; Abdallah, M. A.; Kyslík, Pavel; Kieffer, B.

    2001-01-01

    Roč. 4, - (2001), s. 765-770 ISSN 1387-1609 Institutional research plan: CEZ:AV0Z5020903 Keywords : determination * resonance * assignments Subject RIV: EE - Microbiology, Virology Impact factor: 0.555, year: 2001

  12. Determination of isotope fractionation effect using a double spike (242Pu+240Pu) during the mass spectrometric analysis of plutonium

    International Nuclear Information System (INIS)

    Chitambar, S.A.; Parab, A.R.; Khodade, P.S.; Jain, H.C.

    1986-01-01

    Isotope fractionation effect during the mass spectrometric analysis of plutonium has been investigated using a double spike ( 242 Pu+ 240 Pu) and the determination of concentration of plutonium in dissolver solution of irradiated fuel is reported. (author). 6 refs., 2 tables

  13. On the determination of double diffraction dissociation cross section at HERA

    International Nuclear Information System (INIS)

    Holtmann, H.; Nikolaev, N.N.; Speth, J.; Zakharov, B.G.

    1996-01-01

    The excitation of the proton into undetected multiparticle states (double diffraction dissociation) is an important background to single diffractive deep-inelastic processes ep→e'p'ρ 0 , e'p'J/Ψ, e'p'X at HERA. We present estimates of the admixture of the double diffraction dissociation events in all diffractive events. We find that in the J/Ψ photoproduction, electroproduction of the ρ 0 at large Q 2 and diffraction dissociation of real and virtual photons into high mass states X the contamination of the double diffraction dissociation can be as large as ∼30%, thus affecting substantially the experimental tests of the pomeron exchange in deep inelastic scattering at HERA. We discuss a possibility of tagging the double diffraction dissociation by neutrons observed in the forward neutron calorimeter. We present evaluations of the spectra of neutrons and efficiency of neutron tagging based on the experimental data for diffractive processes in the proton-proton collisions. (orig.)

  14. Focal point determination in magnetic resonance-guided focused ultrasound using tracking coils.

    Science.gov (United States)

    Svedin, Bryant T; Beck, Michael J; Hadley, J Rock; Merrill, Robb; de Bever, Joshua T; Bolster, Bradley D; Payne, Allison; Parker, Dennis L

    2017-06-01

    To develop a method for rapid prediction of the geometric focus location in MR coordinates of a focused ultrasound (US) transducer with arbitrary position and orientation without sonicating. Three small tracker coil circuits were designed, constructed, attached to the transducer housing of a breast-specific MR-guided focused US (MRgFUS) system with 5 degrees of freedom, and connected to receiver channel inputs of an MRI scanner. A one-dimensional sequence applied in three orthogonal directions determined the position of each tracker, which was then corrected for gradient nonlinearity. In a calibration step, low-level heating located the US focus in one transducer position orientation where the tracker positions were also known. Subsequent US focus locations were determined from the isometric transformation of the trackers. The accuracy of this method was verified by comparing the tracking coil predictions to thermal center of mass calculated using MR thermometry data acquired at 16 different transducer positions for MRgFUS sonications in a homogeneous gelatin phantom. The tracker coil predicted focus was an average distance of 2.1 ± 1.1 mm from the thermal center of mass. The one-dimensional locator sequence and prediction calculations took less than 1 s to perform. This technique accurately predicts the geometric focus for a transducer with arbitrary position and orientation without sonicating. Magn Reson Med 77:2424-2430, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  15. Double spike methodology for uranium determination by thermal ionisation mass spectrometry: separation and purification of 234U

    International Nuclear Information System (INIS)

    Shah, P.M.; Saxena, M.K.; Sanjai Kumar; Aggarwal, S.K.; Jain, H.C.

    1995-01-01

    With an objective to prepare double spike of 233 U+ 234 U for determination of uranium concentration by Isotopic Dilution Thermal Ionisation Mass Spectrometry (ID-TIMS), 234 U was separated and purified from aged 238 Pu sample (15 years old) using several ion exchange and solvent extraction procedures. Final product containing 95% and 5% alpha activities of 234 and 238 Pu, respectively, which translates into 99.998 atom% of 234 U and 0.002 atom% of 238 Pu was found suitable for double spike. (author). 1 ref

  16. Determination of the Boltzmann constant using a quasi-spherical acoustic resonator.

    Science.gov (United States)

    Pitre, Laurent; Sparasci, Fernando; Truong, Daniel; Guillou, Arnaud; Risegari, Lara; Himbert, Marc E

    2011-10-28

    The paper reports a new experiment to determine the value of the Boltzmann constant, k(B)=1.3806477(17)×10(-23) J K(-1), with a relative standard uncertainty of 1.2 parts in 10(6). k(B) was deduced from measurements of the velocity of sound in argon, inside a closed quasi-spherical cavity at a temperature of the triple point of water. The shape of the cavity was achieved using an extremely accurate diamond turning process. The traceability of temperature measurements was ensured at the highest level of accuracy. The volume of the resonator was calculated from measurements of the resonance frequencies of microwave modes. The molar mass of the gas was determined by chemical and isotopic composition measurements with a mass spectrometer. Within combined uncertainties, our new value of k(B) is consistent with the 2006 Committee on Data for Science and Technology (CODATA) value: (k(B)(new)/k(B_CODATA)-1)=-1.96×10(-6), where the relative uncertainties are u(r)(k(B)(new))=1.2×10(-6) and u(r)(k(B_CODATA))=1.7×10(-6). The new relative uncertainty approaches the target value of 1×10(-6) set by the Consultative Committee on Thermometry as a precondition for redefining the unit of the thermodynamic temperature, the kelvin.

  17. Determination of protein by resonance light scattering technique using dithiothreitol-sodium dodecylbenzene sulphonate as probe

    Science.gov (United States)

    Wu, Lihang; Mu, Dan; Gao, Dejiang; Deng, Xinyu; Tian, Yuan; Zhang, Hanqi; Yu, Aimin

    2009-02-01

    The resonance light scattering (RLS) spectra of bovine serum albumin (BSA)-dithiothreitol (DTT)-sodium dodecylbenzene sulphonate (SDBS) and its analytical application were investigated. The RLS intensity of this system can be effectively enhanced in the presence of BSA. Based on the enhanced RLS intensity, a simple assay for BSA was developed. The experimental results indicate that the enhanced RLS intensity is proportional to the concentration of BSA in the range from 1.0 × 10 -8 to 7.5 × 10 -7 mol L -1 with the determination limit of 5.0 × 10 -9 mol L -1. The effects of pH, concentration of SDBS and DTT on the RLS enhancement were discussed. Most metal ions have little interference on the determination of BSA. Some synthetic and real samples were analyzed, and the results obtained were in good agreement with those obtained by Bradford method.

  18. Determination of moisture in black coal using pulsed nuclear magnetic resonance spectrometry

    International Nuclear Information System (INIS)

    Cutmore, N.G.; Sowerby, B.D.; Lynch, L.J.; Webster, D.S.

    1987-01-01

    Pulsed nuclear magnetic resonance (n.m.r.) spectrometry was investigated as a technique for moisture determination in fine product coal from eight Australian coal washeries. Measurements were made on samples of diameter 8 and 12 mm and length 10 and 120 mm at frequencies from 6.5 to 60 MHz. The ratio of intensities of the water and coal components in the free-induction decay signal can be used to determine moisture to within approx. 0.4-0.7 wt% over the range 0-26 wt% moisture, independent of sample density. This accuracy is independent of particle size (up to 1 mm) and little affected by coal rank, sample length or n.m.r. frequency. (author)

  19. Fast centroid algorithm for determining the surface plasmon resonance angle using the fixed-boundary method

    International Nuclear Information System (INIS)

    Zhan, Shuyue; Wang, Xiaoping; Liu, Yuling

    2011-01-01

    To simplify the algorithm for determining the surface plasmon resonance (SPR) angle for special applications and development trends, a fast method for determining an SPR angle, called the fixed-boundary centroid algorithm, has been proposed. Two experiments were conducted to compare three centroid algorithms from the aspects of the operation time, sensitivity to shot noise, signal-to-noise ratio (SNR), resolution, and measurement range. Although the measurement range of this method was narrower, the other performance indices were all better than the other two centroid methods. This method has outstanding performance, high speed, good conformity, low error and a high SNR and resolution. It thus has the potential to be widely adopted

  20. [Single or double moral standards? Professional ethics of psychiatrists regarding self-determination, rights of third parties and involuntary treatment].

    Science.gov (United States)

    Pollmächer, T

    2015-09-01

    The current intensive discussion on the legal and moral aspects of involuntary treatment of psychiatric patients raises a number of ethical issues. Physicians are unambiguously obligated to protect patient welfare and autonomy; however, in psychiatric patients disease-related restrictions in the capacity of self-determination and behaviors endangering the rights of third parties can seriously challenge this unambiguity. Therefore, psychiatry is assumed to have a double function and is also obligated to third parties and to society in general. Acceptance of such a kind of double obligation carries the risk of double moral standards, placing the psychiatrist ethically outside the community of physicians and questioning the unrestricted obligation towards the patient. The present article formulates a moral position, which places the psychiatrist, like all other physicians, exclusively on the side of the patient in terms of professional ethics and discusses the practical problems arising from this moral position.

  1. Comparison between arthroscopy and 3 dimensional double echo steady state 3D-DESS sequences in magnetic resonance imaging of internal derangements of the knee

    International Nuclear Information System (INIS)

    Dongola, Nagwa A.; Gishen, Philip

    2004-01-01

    This study was performed with the aim of evaluating the usefulness of 3 dimensional double-echo steady state sequences in examining the internal derangements of the knee. Arthroscopy was used as a referral standard. The study was performed in the Radiology and Arthroscopy Departments of Kings College Hospital, London, United Kingdom, during a 6-month period from January 1997 to June 1997. All patients who had knee magnetic resonance imaging within 3 months of arthroscopy were retrospectively studied. Thirty-three patients fulfilled these criteria and were selected. Three dimensional double-echo steady state sequences produced sensitivity for detecting meniscal tears of 87.5% for medial menisci (MM) and 75% for lateral menisci (LM). Specificity was 76% for MM and 96% for LM; positive predictive value (PPV) was 46.1% for MM and 85.7% for LM and negative predictive value (NPV) of 95% for MM and 96% for LM. The sensitivity for the anterior cruciate ligament was 83.3%, specificity was 77.7%, PPV was 45.4% and NPV was 95.4%. Three dimensional double-echo steady state sequences are useful in evaluating internal derangement of the knee, especially in advanced cartilage lesions. (author)

  2. Double dosimetry procedures for the determination of occupational effective dose in interventional radiology

    International Nuclear Information System (INIS)

    Jaervinen, H.; Buls, N.; Clerinx, P.; Miljanic, S.; Ranogajec-Komor, M.; Nikodemova, D.; D'Errico, F.

    2008-01-01

    Full text: In interventional radiology, for an accurate determination of occupational effective dose, measurements with two dosemeters ('double dosimetry', DD) have been recommended, one dosemeter located above and one under the protective apron. In this paper, based on an extensive literature search, the most recent algorithms developed for the determination of effective dose from the dosimeter readings have been compared for a few practical interventional procedures. Recommendations on the practices and algorithms are given on the basis of the results. For the comparison of algorithms, dosemeter readings and the effective dose were obtained both experimentally and by calculation. Further, data from published Monte Carlo calculations have been applied. The literature review has indicated that very few regulations for DD exist and the DD practices have not been harmonized. There is no firm consensus on the most suitable calculation algorithms. Single dosemeter (SD) measurements are still mostly used for the calculation of effective dose. Most DD and SD algorithms overestimate effective dose significantly, sometimes by over ten times. However, SD algorithms can significantly underestimate effective dose in certain interventional radiology conditions. Due to the possibility of underestimating effective dose, DD is generally recommended. The results suggest that there might not be a single DD algorithm which would be optimum for all interventional radiology procedures. However, the selection of a precise DD algorithm for each individual condition is not practical and compromises must be made. For accurate personnel dosimetry, the accuracy of the algorithm selected should be tested for typical local interventional radiology condition. Personnel dosemeters should be used in the recommended positions. The dosemeter above the apron should be on a collar and its reading also used to assess the risk of lens injuries. The dosemeter under the apron can be on the chest or

  3. GEM-loaded magnetic albumin nanospheres modified with cetuximab for simultaneous targeting, magnetic resonance imaging, and double-targeted thermochemotherapy of pancreatic cancer cells.

    Science.gov (United States)

    Wang, Ling; An, Yanli; Yuan, Chenyan; Zhang, Hao; Liang, Chen; Ding, Fengan; Gao, Qi; Zhang, Dongsheng

    2015-01-01

    Targeted delivery is a promising strategy to improve the diagnostic imaging and therapeutic effect of cancers. In this paper, novel cetuximab (C225)-conjugated, gemcitabine (GEM)-containing magnetic albumin nanospheres (C225-GEM/MANs) were fabricated and applied as a theranostic nanocarrier to conduct simultaneous targeting, magnetic resonance imaging (MRI), and double-targeted thermochemotherapy against pancreatic cancer cells. Fe3O4 nanoparticles (NPs) and GEM co-loaded albumin nanospheres (GEM/MANs) were prepared, and then C225 was further conjugated to synthesize C225-GEM/MANs. Their morphology, mean particle size, GEM encapsulation ratio, specific cell-binding ability, and thermal dynamic profiles were characterized. The effects of discriminating different EGFR-expressing pancreatic cancer cells (AsPC-1 and MIA PaCa-2) and monitoring cellular targeting effects were assessed by targeted MRI. Lastly, the antitumor efficiency of double/C225/magnetic-targeted and nontargeted thermochemotherapy was compared with chemotherapy alone using 3-(4, 5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) and flow cytometry (FCM) assay. When treated with targeted nanospheres, AsPC-1 cells showed a significantly less intense MRI T2 signal than MIA PaCa-2 cells, while both cells had similar signal strength when incubated with nontargeted nanospheres. T2 signal intensity was significantly lower when magnetic and C225 targeting were combined, rather than used alone. The inhibitory and apoptotic rates of each thermochemotherapy group were significantly higher than those of the chemotherapy-alone groups. Additionally, both MTT and FCM analysis verified that double-targeted thermochemotherapy had the highest targeted killing efficiency among all groups. The C225-GEM/MANs can distinguish various EGFR-expressing live pancreatic cancer cells, monitor diverse cellular targeting effects using targeted MRI imaging, and efficiently mediate double-targeted thermochemotherapy

  4. Nuclear magnetic resonance spectroscopy for determining the functional content of organic aerosols: A review

    International Nuclear Information System (INIS)

    Chalbot, Marie-Cecile G.; Kavouras, Ilias G.

    2014-01-01

    The knowledge deficit of organic aerosol (OA) composition has been identified as the most important factor limiting our understanding of the atmospheric fate and implications of aerosol. The efforts to chemically characterize OA include the increasing utilization of nuclear magnetic resonance spectroscopy (NMR). Since 1998, the functional composition of different types, sizes and fractions of OA has been studied with one-dimensional, two-dimensional and solid state proton and carbon-13 NMR. This led to the use of functional group ratios to reconcile the most important sources of OA, including secondary organic aerosol and initial source apportionment using positive matrix factorization. Future research efforts may be directed towards the optimization of experimental parameters, detailed NMR experiments and analysis by pattern recognition methods to identify the chemical components, determination of the NMR fingerprints of OA sources and solid state NMR to study the content of OA as a whole. - Highlights: • Organic aerosol composition by 1 H- and 13 C-NMR spectroscopy. • NMR fingerprints of specific sources, types and sizes of organic aerosol. • Source reconciliation and apportionment using NMR spectroscopy. • Research priorities towards understanding organic aerosol composition and origin. - This review presents the recent advances on the characterization of organic aerosol composition using nuclear magnetic resonance spectroscopy

  5. Determination of the hadronic resonance parameters of the Zo boson with DELPHI spectrometers at LEP

    International Nuclear Information System (INIS)

    Djama, F.

    1991-05-01

    The work described was achieved on the DELPHI experiment at the LEP e + e - collider. It concerns the determination of the resonance parameters of the Z 0 boson (M z , Γ z and σ o ) through its hadronic decays. The cross-section for the production of quark-antiquark pairs in e + e - collisions was measured at 17 different collision energies close to the resonance peak. At first, a general review of the Standard Model and its predictions for the cross-section of the process e + e - → γ, Z 0 → qantiq are given, followed by a description of the LEP collider and of the DELPHI detector. The different steps of the analysis are then exposed. They concern the luminosity measurement, the selection of the hadronic events and the computation of the experimental cross-sections. Special attention was given to the systematic errors. In order to extract the resonance parameters and to test the Standard Model, the experimental cross-sections were fitted with a theoretical formula which includes the most up-to-date radiative corrections calculations. A three parameter fit gives: M z = 91.183 ± 0.011 (stat) ± 0.02 (LEP) GeV/c 2 Γ z = 2.465 ± 0.020 (stat) ± 0.005 (syst) GeV σ o = 41.92 ± 0.22 (stat) ± 0.33 (syst) ± 0.21 (theo) nb Χ 2 /d.o.f = 8.5/17 - 3. By combining these results with the Standard Model predictions for the leptonic widths, we derived the invisible width of the Z 0 resonance: Γ inv = 486 ± 7 (stat) ± 12 (syst) MeV. This result leads to the following value for the number of the light Dirac neutrino species: N ν = 2.92 ± 0.04 (stat) ± 0.07 (syst). The total and invisible widths were used to derive lower bounds of the masses of new particles predicted either by the Minimal Standard Model (top quark) or by its extensions and alternatives (4 th sequential family, sparticles, excited fermions) [fr

  6. Quantitative determination of Quarternary alicyclic carbon atoms in coal and oil using nuclear magnetic resonance /sup 13/C method

    Energy Technology Data Exchange (ETDEWEB)

    Afonina, T.V.; Kushnarev, D.F.; Randin, O.I.; Shishkov, V.F.; Kalabin, G.A.

    1986-09-01

    Possibility is indicated for utilizing nuclear magnetic resonance spectroscopy for quantitative determination of Quarternary aliphatic carbon atoms in heavy hydrocarbon fractions of oil and coal extracts. C/sub n/, CH, CH/sub 2/ and CH/sub 3/ content in coal and oil samples are determined and corresponding resonance lines are referred to individual structural fragments (on the basis of nuclear magnetic resonance /sup 13/C spectra) of known saturated hydrocarbons. Tests were carried out on chloroform extracts of Irsha-Borodinsk coal, Mungunsk coal and paraffin and cycloparaffin of Sivinsk oil (b.p. over 550 C) fractions. Nuclear magnetic resonance spectra were obtained using Burker WP 200 spectrometer (50.13 MHz frequency). Results of the tests are given. 11 references.

  7. Determination of scutellarin in breviscapine preparations using quantitative proton nuclear magnetic resonance spectroscopy

    Directory of Open Access Journals (Sweden)

    Zhenzuo Jiang

    2016-04-01

    Full Text Available The objective of the present study was to develop the selection criteria of proton signals for the determination of scutellarin using quantitative nuclear magnetic resonance (qNMR, which is the main bioactive compound in breviscapine preparations for the treatment of cerebrovascular disease. The methyl singlet signal of 3-(trimethylsilylpropionic-2,2,3,3-d4 acid sodium salt was selected as the internal standard for quantification. The molar concentration of scutellarin was determined by employing different proton signals. To obtain optimum proton signals for the quantification, different combinations of proton signals were investigated according to two selection criteria: the recovery rate of qNMR method and quantitative results compared with those obtained with ultra-performance liquid chromatography. As a result, the chemical shift of H-2′ and H-6′ at δ 7.88 was demonstrated as the most suitable signal with excellent linearity range, precision, and recovery for determining scutellarin in breviscapine preparations from different manufacturers, batch numbers, and dosage forms. Hierarchical cluster analysis was employed to evaluate the determination results. The results demonstrated that the selection criteria of proton signals established in this work were reliable for the qNMR study of scutellarin in breviscapine preparations.

  8. Determination of azide in biological fluids by use of electron paramagnetic resonance

    International Nuclear Information System (INIS)

    Minakata, Kayoko; Suzuki, Osamu

    2005-01-01

    A simple and sensitive method has been developed for the determination of azide ion (N 3 - ) in biological fluids and beverages. The procedure was based on the formation of a ternary complex Cu(N 3 ) 2 (4-methylpyridine) x in benzene, followed by its detection by electron paramagnetic resonance. The complex in benzene showed a characteristic four-peak hyperfine structure with a g-value of 2.115 at room temperature. Cu 2+ reacted with N 3 - most strongly among common metals found in biological fluids. Several anions and metal ions in biological fluids did not interfere with the determination of N 3 - in the presence of large amounts of Cu 2+ and oxidants. In the present method, N 3 - at the concentration from 5 μM to 2 mM in 100 μl solution could be determined with the detection limit of 20 ng. The recoveries were more than 95% for N 3 - added to 100 μl of blood, urine, milk and beverages at 200 μM. Our method is recommendable because it takes less than 10 min to determine N 3 - and the produced complex is quite stable

  9. Double-phase 18F-FDG PET-CT for determination of pulmonary tuberculoma activity

    International Nuclear Information System (INIS)

    Kim, In-Ju; Kim, Seong-Jang; Kim, Yong-Ki; Lee, Jung Sub; Jeong, Yeon Joo; Jun, Sungmin; Nam, Hyun Yul; Kim, Ju Sung

    2008-01-01

    The aim of this study is to evaluate the potential role of double phase acquisition of 18 F fluorodeoxyglucose (FDG) positron emission tomography (PET) for the differentiation of active pulmonary tuberculoma. A total of 25 consecutive patients with pulmonary tuberculoma were enrolled. PET/CT imaging was performed 60 (range 53-71) and 120 min (range 109-131) after injection of 18 F-FDG. The intensity of 18 F-FDG uptake by pulmonary lesions was assessed visually, and the intensity was scored with a four-point scale (grade 1: absent, grade 2: faint, grade 3: moderate, grade 4: intense). Active tuberculoma shows statistically significant higher values in maximal standardized uptake values SUV maxE (active = 2.3 ± 0.75, inactive 0.79 ± 0.15), SUV maxD (active = 2.48 ± 0.79, inactive = 0.75 ± 0.13), and %ΔSUV max (active = 8.07 ± 7.77%, inactive = -3.83 ± 6.59) than those of inactive tuberculoma. When greater than or equal to visual grade 2 was used as the cutoff value, the sensitivity and specificity were 100 and 81.8%. When SUV maxE 1.05 was used as the cutoff point, the sensitivity and specificity were 100 and 100%. When SUV maxD 0.97 was used as the cutoff value, the sensitivity and specificity were 92.8 and 100%. When %ΔSUV max 6.59 was used as the cutoff value, the sensitivity and specificity were 71.4 and 100%. The %ΔSUV max was the potent predictor by logistic regression analysis. The ΔSUV max is a potential predictor for activity of pulmonary tuberculoma. However, the diagnostic performances were similar between visual and quantitative analyses. The visual assessment may be sufficient for determination of pulmonary tuberculoma activity. Further studies are needed to confirm these results and improve statistical accuracy. (orig.)

  10. Proton chemical shift tensors determined by 3D ultrafast MAS double-quantum NMR spectroscopy

    International Nuclear Information System (INIS)

    Zhang, Rongchun; Mroue, Kamal H.; Ramamoorthy, Ayyalusamy

    2015-01-01

    Proton NMR spectroscopy in the solid state has recently attracted much attention owing to the significant enhancement in spectral resolution afforded by the remarkable advances in ultrafast magic angle spinning (MAS) capabilities. In particular, proton chemical shift anisotropy (CSA) has become an important tool for obtaining specific insights into inter/intra-molecular hydrogen bonding. However, even at the highest currently feasible spinning frequencies (110–120 kHz), 1 H MAS NMR spectra of rigid solids still suffer from poor resolution and severe peak overlap caused by the strong 1 H– 1 H homonuclear dipolar couplings and narrow 1 H chemical shift (CS) ranges, which render it difficult to determine the CSA of specific proton sites in the standard CSA/single-quantum (SQ) chemical shift correlation experiment. Herein, we propose a three-dimensional (3D) 1 H double-quantum (DQ) chemical shift/CSA/SQ chemical shift correlation experiment to extract the CS tensors of proton sites whose signals are not well resolved along the single-quantum chemical shift dimension. As extracted from the 3D spectrum, the F1/F3 (DQ/SQ) projection provides valuable information about 1 H– 1 H proximities, which might also reveal the hydrogen-bonding connectivities. In addition, the F2/F3 (CSA/SQ) correlation spectrum, which is similar to the regular 2D CSA/SQ correlation experiment, yields chemical shift anisotropic line shapes at different isotropic chemical shifts. More importantly, since the F2/F1 (CSA/DQ) spectrum correlates the CSA with the DQ signal induced by two neighboring proton sites, the CSA spectrum sliced at a specific DQ chemical shift position contains the CSA information of two neighboring spins indicated by the DQ chemical shift. If these two spins have different CS tensors, both tensors can be extracted by numerical fitting. We believe that this robust and elegant single-channel proton-based 3D experiment provides useful atomistic-level structural and dynamical

  11. Determination of the electromagnetic field in a high-Tc linear superconducting resonator

    International Nuclear Information System (INIS)

    Trotel, A.; Sautrot, S.; Pyee, M.

    1994-01-01

    In this paper, the electromagnetic field configuration in a linear SHTC resonator is described. Two areas are considered: 1) the superconducting strip, 2) the dielectric around the strip. The calculation is based on the current density given by Bowers for an infinite superconducting line. The current density in the resonator is defined by these relations and the resonance conditions. (orig.)

  12. Mass and Position Determination in MEMS Resonant Mass Sensors: Theoretical and Experimental Investigation

    KAUST Repository

    Bouchaala, Adam M.; Nayfeh, Ali H.; Jaber, Nizar; Younis, Mohammad I.

    2016-01-01

    We present a method to determine accurately the position and mass of an entity attached to the surface of an electrostatically actuated clamped-clamped microbeam implemented as a mass sensor. In the theoretical investigation, the microbeam is modeled as a nonlinear Euler-Bernoulli beam and a perturbation technique is used to develop a closed-form expression for the frequency shift due to an added mass at a specific location on the microbeam surface. The experimental investigation was conducted on a microbeam made of Polyimide with a special lower electrode to excite both of the first and second modes of vibration. Using an ink-jet printer, we deposited droplets of polymers with a defined mass and position on the surface of the microbeam and we measured the shifts in its resonance frequencies. The theoretical predictions of the mass and position of the deposited droplets match well with the experimental measurements.

  13. Mass and Position Determination in MEMS Resonant Mass Sensors: Theoretical and Experimental Investigation

    KAUST Repository

    Bouchaala, Adam M.

    2016-12-05

    We present a method to determine accurately the position and mass of an entity attached to the surface of an electrostatically actuated clamped-clamped microbeam implemented as a mass sensor. In the theoretical investigation, the microbeam is modeled as a nonlinear Euler-Bernoulli beam and a perturbation technique is used to develop a closed-form expression for the frequency shift due to an added mass at a specific location on the microbeam surface. The experimental investigation was conducted on a microbeam made of Polyimide with a special lower electrode to excite both of the first and second modes of vibration. Using an ink-jet printer, we deposited droplets of polymers with a defined mass and position on the surface of the microbeam and we measured the shifts in its resonance frequencies. The theoretical predictions of the mass and position of the deposited droplets match well with the experimental measurements.

  14. Determination of 90Sr in environmental samples with resonance ionization spectroscopy in collinear geometry

    International Nuclear Information System (INIS)

    Zimmer, K.; Stenner, J.; Kluge, H.J.; Lantzsch, J.; Monz, L.; Otten, E.W.; Passler, G.; Schwalbach, R.; Schwarz, M.; Stevens, H.; Wendt, K.; Herrmann, G.; Niess, S.; Trautmann, N.; Walter, K.; Bushaw, B.A.

    1994-01-01

    A new, fast technique for trace analysis of the radioactive isotopes 89 Sr and 90 Sr in environmental samples has been developed. Conventional mass separation is combined with resonance ionization spectroscopy in collinear geometry, which provides high selectivity and sensitivity. In addition, a chemical separation procedure for sample preparation has been developed. The described technique was used to determine the 90 Sr content in ∼ 870 m 3 air samples collected near Munich during and shortly after the Chernobyl reactor accident in April 1986. The content of 90 Sr was measured to be 1.4 mBq per m 3 , corresponding to 1.6 x 10 9 atoms of 90 Sr per sample. This value is in good agreement with the results of radiochemical measurements. (orig.)

  15. Determination of [sup 90]Sr in environmental samples with resonance ionization spectroscopy in collinear geometry

    Energy Technology Data Exchange (ETDEWEB)

    Zimmer, K. (Inst. fuer Physik, Univ. Mainz (Germany)); Stenner, J. (Inst. fuer Physik, Univ. Mainz (Germany)); Kluge, H.J. (Inst. fuer Physik, Univ. Mainz (Germany)); Lantzsch, J. (Inst. fuer Physik, Univ. Mainz (Germany)); Monz, L. (Inst. fuer Physik, Univ. Mainz (Germany)); Otten, E.W. (Inst. fuer Physik, Univ. Mainz (Germany)); Passler, G. (Inst. fuer Physik, Univ. Mainz (Germany)); Schwalbach, R. (Inst. fuer Physik, Univ. Mainz (Germany)); Schwarz, M. (Inst. fuer Physik, Univ. Mainz (Germany)); Stevens, H. (Inst. fuer Physik, Univ. Mainz (Germany)); Wendt, K. (Inst. fuer Physik, Univ. Mainz (Germany)); Herrmann, G. (Inst. fuer Kernchemie, Univ. Mainz (Germany)); Niess, S. (Inst. fuer Kernchemie, Univ. Mainz (Germany)); Trautmann, N. (Inst. fuer Kernchemie, Univ. Mainz (Germany)); Walter, K. (Inst. fuer Kernchemie, Univ. Mainz (Germany)); Bushaw, B.A. (Pacific Northwest Lab., Richland, WA (United States))

    1994-08-01

    A new, fast technique for trace analysis of the radioactive isotopes [sup 89]Sr and [sup 90]Sr in environmental samples has been developed. Conventional mass separation is combined with resonance ionization spectroscopy in collinear geometry, which provides high selectivity and sensitivity. In addition, a chemical separation procedure for sample preparation has been developed. The described technique was used to determine the [sup 90]Sr content in [approx] 870 m[sup 3] air samples collected near Munich during and shortly after the Chernobyl reactor accident in April 1986. The content of [sup 90]Sr was measured to be 1.4 mBq per m[sup 3], corresponding to 1.6 x 10[sup 9] atoms of [sup 90]Sr per sample. This value is in good agreement with the results of radiochemical measurements. (orig.)

  16. Determination of Activated Carbon Residual Life using a Microwave Cavity Resonator

    International Nuclear Information System (INIS)

    Mason, A; Wylie, S; Shaw, A; Al-Shamma'a, A I; Thomas, A; Keele, H

    2011-01-01

    This paper presents the continuation of work conducted jointly between Dstl and LJMU. This unique body of work has been, largely, concerned with detecting the residual life of high performance filter materials using electromagnetic (EM) waves within a resonant cavity. Past work has considered both HEPA [1] and ASZM-TEDA[2] activated carbon filter materials. This paper continues the later work, considering the response of ASZM-TEDA activated carbon through the co-ageing of two distinct batches of the material. The paper briefly introduces activated carbon, discusses theory relevant to the work and the methodology used for investigation. A comprehensive set of results is included which seek to validate this technique for determining the residual lifespan of activated carbon.

  17. Singular Value Decomposition Method to Determine Distance Distributions in Pulsed Dipolar Electron Spin Resonance.

    Science.gov (United States)

    Srivastava, Madhur; Freed, Jack H

    2017-11-16

    Regularization is often utilized to elicit the desired physical results from experimental data. The recent development of a denoising procedure yielding about 2 orders of magnitude in improvement in SNR obviates the need for regularization, which achieves a compromise between canceling effects of noise and obtaining an estimate of the desired physical results. We show how singular value decomposition (SVD) can be employed directly on the denoised data, using pulse dipolar electron spin resonance experiments as an example. Such experiments are useful in measuring distances and their distributions, P(r) between spin labels on proteins. In noise-free model cases exact results are obtained, but even a small amount of noise (e.g., SNR = 850 after denoising) corrupts the solution. We develop criteria that precisely determine an optimum approximate solution, which can readily be automated. This method is applicable to any signal that is currently processed with regularization of its SVD analysis.

  18. Magnetic resonance electrical impedance tomography for determining electric field distribution during electroporation

    International Nuclear Information System (INIS)

    Kranjc, Matej; Miklavcic, Damijan; Bajd, Franci; Serša, Igor

    2013-01-01

    Electroporation is a phenomenon caused by externally applied electric field to cells that results in an increase of cell membrane permeability to various molecules. Accurate coverage of the tissue with a sufficiently large electric field presents one of the most important conditions for successful membrane permeabilization. Applications based on electroporation would greatly benefit with a method for monitoring the electric field, especially if it could be done in situ. As the membrane electroporation is a consequence of an induced transmembrane potential, which is directly proportional to the local electric field, we have been investigating current density imaging and magnetic resonance electrical impedance tomography techniques to determine the electric field distribution during electroporation. In this paper, we present comparison of current density and electric field distribution in an agar phantom and in a liver tissue exposed to electroporation pulses. As expected, a region of increased electrical conductivity was observed in the liver tissue exposed to sufficiently high electric field but not in agar phantom.

  19. Resonance light scattering technique for the determination of proteins with polymethacrylic acid (PMAA)

    Science.gov (United States)

    Chen, Yanhua; Gao, Dejiang; Tian, Yuan; Ai, Peng; Zhang, Hanqi; Yu, Aimin

    2007-07-01

    As a resonance light scattering (RLS) probe, the polyelectrolyte polymethacrylic acid (PMAA) was applied in this assay. The bovine serum albumin (BSA) and human serum albumin (HSA) were determined by the electrostatic interaction of PMAA and proteins. At pH 3.8 Na 2HPO 4-citric acid buffer solution, the RLS intensities of PMAA-BSA (HSA) system were greatly enhanced. The characteristic peaks were appeared at the wavelength 320, 546 and 594 nm. The optimization conditions of the reaction were also examined and selected. Under the selected conditions, the RLS intensities were proportional to the protein concentrations in the range of (0.0200-2.00) × 10 -6 mol/L for BSA and (0.0200-2.40) × 10 -6 mol/L for HSA. The influences of some foreign substances were also examined. The synthetic samples containing proteins and some real samples were analyzed and the results obtained were satisfactory.

  20. Determination of the first ionization potential of actinides by resonance ionization mass spectroscopy

    International Nuclear Information System (INIS)

    Koehler, S.; Albus, F.; Dibenberger, R.; Erdmann, N.; Funk, H.; Hasse, H.; Herrmann, G.; Huber, G.; Kluge, H.; Nunnemann, M.; Passler, G.; Rao, P.M.; Riegel, J.; Trautmann, N.; Urban, F.

    1995-01-01

    Resonance ionization mass spectroscopy (RIMS) is used for the precise determination of the first ionization potential of transuranium elements. The first ionization potentials (IP) of americium and curium have been measured for the first time to IP Am =5.9738(2) and IP Cm =5.9913(8) eV, respectively, using only 10 12 atoms of 243 Am and 248 Cm. The same technique was applied to thorium, neptunium, and plutonium yielding IP T H =6.3067(2), IP N P =6.2655(2), and IP Pu =6.0257(8) eV. The good agreement of our results with the literature data proves the precision of the method which was additionally confirmed by the analysis of Rydberg seris of americium measured by RIMS. copyright American Institute of Physics 1995

  1. The double-resonance enhancement of stimulated low-frequency Raman scattering in silver-capped nanodiamonds

    Science.gov (United States)

    Baranov, A. N.; Butsen, A. V.; Ionin, A. A.; Ivanova, A. K.; Kuchmizhak, A. A.; Kudryashov, S. I.; Kudryavtseva, A. D.; Levchenko, A. O.; Rudenko, A. A.; Saraeva, I. N.; Strokov, M. A.; Tcherniega, N. V.; Zayarny, D. A.

    2017-09-01

    Hybrid plasmonic-dielectric nano- and (sub)microparticles exhibit magnetic and electrical dipolar Mie-resonances, which makes them useful as efficient basic elements in surface-enhanced spectroscopy, non-linear light conversion and nanoscale light control. We report the stimulated low-frequency Raman scattering (SLFRS) of a nanosecond ruby laser radiation (central wavelength λ = 694.3 nm (full-width at half-maximum ≈ 0.015 cm-1), gaussian 1/e-intensity pulsewidth τ ≈ 20 ns, TEM00-mode pulse energy Emax ≈ 0.3 J) in nanodiamond (R ≈ 120 nm) hydrosols, induced via optomechanical coherent excitation of fundamental breathing eigen-modes, and the two-fold enhancement of SLFRS in Ag-decorated nanodiamonds, characterized by hybrid dipolar resonances of electrical (silver) and magnetic (diamond) nature. Hybrid metal-dielectric particles were prepared by means of nanosecond IR-laser ablation of solid silver target in diamond hydrosols with consecutive Ag-capping of diamonds, and were characterized by scanning electron microscopy, UV-vis, photoluminescence and energy-dispersive X-ray spectroscopy. Intensities of the SLFR-scattered components and their size-dependent spectral shifts were measured in the highly sensitive stimulated scattering regime, indicating the high (≈ 30%) SLFRS conversion efficiency and the resonant character of the scattering species.

  2. Double-resonance optical-pumping effect and ladder-type electromagnetically induced transparency signal without Doppler background in cesium atomic vapour cell

    International Nuclear Information System (INIS)

    Yang Bao-Dong; Gao Jing; Liang Qiang-Bing; Wang Jie; Zhang Tian-Cai; Wang Jun-Min

    2011-01-01

    In a Doppler-broadened ladder-type cesium atomic system (6S 1/2 -6P 3/2 -8S 1/2 ), this paper characterizes electromagnetically induced transparency (EIT) in two different experimental arrangements, and investigates the influence of the double-resonance optical-pumping (DROP) effect on EIT in both arrangements. When the probe laser is weak, DROP is explicitly suppressed. When the probe laser is moderate, population of the intermediate level (6P 3/2 F' = 5) is remarkable, therefore DROP is mixed with EIT. An interesting bimodal spectrum with the broad component due to DROP and the narrow part due to EIT has been clearly observed in cesium 6S 1/2 F = 4−6P 3/2 F' = 5−8S 1/2 F″ = 4 transitions. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  3. A novel method for quantitative determination of tea polysaccharide by resonance light scattering

    Science.gov (United States)

    Wei, Xinlin; Xi, Xionggang; Wu, Muxia; Wang, Yuanfeng

    2011-09-01

    A new method for the determination of tea polysaccharide (TPS) in green tea ( Camellia sinensis) leaves has been developed. The method was based on the enhancement of resonance light scattering (RLS) of TPS in the presence of cetylpyridinium chloride (CPC)-NaOH system. Under the optimum conditions, the RLS intensity of CPC was greatly enhanced by adding TPS. The maximum peak of the enhanced RLS spectra was located at 484.02 nm. The enhanced RLS intensity was proportional to the concentration of TPS in the range of 2.0-20 μg/ml. It showed that the new method and phenol-sulfuric acid method give some equivalent results by measuring the standard compounds. The recoveries of the two methods were 96.39-103.7% (novel method) and 100.15-103.65% (phenol-sulfuric acid method), respectively. However, it showed that the two methods were different to some extent. The new method offered a limit of detection (LOD) of 0.047 μg/ml, whereas the phenol-sulfuric acid method gives a LOD of 1.54 μg/ml. Interfered experiment demonstrated that the new method had highly selectivity, and was more suitable for the determination of TPS than phenol-sulfuric method. Stability test showed that new method had good stability. Moreover, the proposed method owns the advantages of easy operation, rapidity and practicability, which suggested that the proposed method could be satisfactorily applied to the determination of TPS in green tea.

  4. Solution Method and Precision Analysis of Double-difference Dynamic Precise Orbit Determination of BeiDou Navigation Satellite System

    Directory of Open Access Journals (Sweden)

    LIU Weiping

    2016-02-01

    Full Text Available To resolve the high relativity between the transverse element of GEO orbit and double-difference ambiguity, the classical double-difference dynamic method is improved and the method, which is to determine precise BeiDou satellite orbit using carrier phase and pseudo-range smoothed by phase, is proposed. The feasibility of the method is discussed and the influence of the method about ambiguity fixing is analyzed. Considering the characteristic of BeiDou, the method, which is to fix double-difference ambiguity of BeiDou satellites by QIF, is derived. The real data analysis shows that the new method, which can reduce the relativity and assure the precision, is better than the classical double-difference dynamic method. The result of ambiguity fixing is well by QIF, but the ambiguity fixing success rate is not high on the whole. So the precision of BeiDou orbit can't be improved clearly after ambiguity fixing.

  5. Aluminum and gallium nuclei as microscopic probes for pulsed electron-nuclear double resonance diagnostics of electric-field gradient and spin density in garnet ceramics doped with paramagnetic ions

    Science.gov (United States)

    Uspenskaya, Yu. A.; Mamin, G. V.; Babunts, R. A.; Badalyan, A. G.; Edinach, E. V.; Asatryan, H. R.; Romanov, N. G.; Orlinskii, S. B.; Khanin, V. M.; Wieczorek, H.; Ronda, C.; Baranov, P. G.

    2018-03-01

    The presence of aluminum and gallium isotopes with large nuclear magnetic and quadrupole moments in the nearest environment of impurity ions Mn2+ and Ce3+ in garnets made it possible to use hyperfine and quadrupole interactions with these ions to determine the spatial distribution of the unpaired electron and the gradient of the electric field at the sites of aluminum and gallium in the garnet lattice. High-frequency (94 GHz) electron spin echo detected electron paramagnetic resonance and electron-nuclear double resonance measurements have been performed. Large difference in the electric field gradient and quadrupole splitting at octahedral and tetrahedral sites allowed identifying the positions of aluminum and gallium ions in the garnet lattice and proving that gallium first fills tetrahedral positions in mixed aluminum-gallium garnets. This should be taken into account in the development of garnet-based scintillators and lasers. It is shown that the electric field gradient at aluminum nuclei near Mn2+ possessing an excess negative charge in the garnet lattice is ca. 2.5 times larger than on aluminum nuclei near Ce3+.

  6. Determining the dominant partial wave contributions from angular distributions of single- and double-polarization observables in pseudoscalar meson photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Wunderlich, Y.; Afzal, F.; Thiel, A.; Beck, R. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany)

    2017-05-15

    This work presents a simple method to determine the significant partial wave contributions to experimentally determined observables in pseudoscalar meson photoproduction. First, fits to angular distributions are presented and the maximum orbital angular momentum L{sub max} needed to achieve a good fit is determined. Then, recent polarization measurements for γp → π{sup 0}p from ELSA, GRAAL, JLab and MAMI are investigated according to the proposed method. This method allows us to project high-spin partial wave contributions to any observable as long as the measurement has the necessary statistical accuracy. We show, that high precision and large angular coverage in the polarization data are needed in order to be sensitive to high-spin resonance states and thereby also for the finding of small resonance contributions. This task can be achieved via interference of these resonances with the well-known states. For the channel γp → π{sup 0}p, those are the N(1680)(5)/(2){sup +} and Δ(1950)(7)/(2){sup +}, contributing to the F-waves. (orig.)

  7. Double agents and secret agents: the emerging fields of exogenous chemical exchange saturation transfer and T2-exchange magnetic resonance imaging contrast agents for molecular imaging.

    Science.gov (United States)

    Daryaei, Iman; Pagel, Mark D

    2015-01-01

    Two relatively new types of exogenous magnetic resonance imaging contrast agents may provide greater impact for molecular imaging by providing greater specificity for detecting molecular imaging biomarkers. Exogenous chemical exchange saturation transfer (CEST) agents rely on the selective saturation of the magnetization of a proton on an agent, followed by chemical exchange of a proton from the agent to water. The selective detection of a biomarker-responsive CEST signal and an unresponsive CEST signal, followed by the ratiometric comparison of these signals, can improve biomarker specificity. We refer to this improvement as a "double-agent" approach to molecular imaging. Exogenous T 2 -exchange agents also rely on chemical exchange of protons between the agent and water, especially with an intermediate rate that lies between the slow exchange rates of CEST agents and the fast exchange rates of traditional T 1 and T 2 agents. Because of this intermediate exchange rate, these agents have been relatively unknown and have acted as "secret agents" in the contrast agent research field. This review exposes these secret agents and describes the merits of double agents through examples of exogenous agents that detect enzyme activity, nucleic acids and gene expression, metabolites, ions, redox state, temperature, and pH. Future directions are also provided for improving both types of contrast agents for improved molecular imaging and clinical translation. Therefore, this review provides an overview of two new types of exogenous contrast agents that are becoming useful tools within the armamentarium of molecular imaging.

  8. Absence of DNA double-strand breaks in human peripheral blood mononuclear cells after 3 Tesla magnetic resonance imaging assessed by γH2AX flow cytometry

    Energy Technology Data Exchange (ETDEWEB)

    Fasshauer, Martin; Staab, Wieland; Sohns, Jan M.; Ritter, Christian; Lotz, Joachim [Goettingen Heart Center, Department of Diagnostic and Interventional Radiology, University Medical Center Goettingen (Germany); German Centre for Cardiovascular Research (DZHK), Goettingen (Germany); Kruewel, Thomas; Stahnke, Vera C. [Goettingen Heart Center, Department of Diagnostic and Interventional Radiology, University Medical Center Goettingen (Germany); Zapf, Antonia [University Medical Center Goettingen, Department of Medical Statistics, Goettingen (Germany); Rave-Fraenk, Margret [University Medical Center Goettingen, Department of Radiotherapy and Radiooncology, Goettingen (Germany); Steinmetz, Michael [German Centre for Cardiovascular Research (DZHK), Goettingen (Germany); Goettingen Heart Center, Department of Pediatric Cardiology and Intensive Care Medicine, University Medical Center Goettingen (Germany); Unterberg-Buchwald, Christina [Goettingen Heart Center, Department of Diagnostic and Interventional Radiology, University Medical Center Goettingen (Germany); German Centre for Cardiovascular Research (DZHK), Goettingen (Germany); Goettingen Heart Center, Department of Cardiology and Pneumology, University Medical Center Goettingen (Germany); Schuster, Andreas [German Centre for Cardiovascular Research (DZHK), Goettingen (Germany); Goettingen Heart Center, Department of Cardiology and Pneumology, University Medical Center Goettingen (Germany)

    2018-03-15

    Magnetic resonance imaging (MRI) is regarded as a non-harming and non-invasive imaging modality with high tissue contrast and almost no side effects. Compared to other cross-sectional imaging modalities, MRI does not use ionising radiation. Recently, however, strong magnetic fields as applied in clinical MRI scanners have been suspected to induce DNA double-strand breaks in human lymphocytes. In this study we investigated the impact of 3-T cardiac MRI examinations on the induction of DNA double-strand breaks in peripheral mononuclear cells by γH2AX staining and flow cytometry analysis. The study cohort consisted of 73 healthy non-smoking volunteers with 36 volunteers undergoing CMRI and 37 controls without intervention. Differences between the two cohorts were analysed by a mixed linear model with repeated measures. Both cohorts showed a significant increase in the γH2AX signal from baseline to post-procedure of 6.7 % (SD 7.18 %) and 7.8 % (SD 6.61 %), respectively. However, the difference between the two groups was not significant. Based on our study, γH2AX flow cytometry shows no evidence that 3-T MRI examinations as used in cardiac scans impair DNA integrity in peripheral mononuclear cells. (orig.)

  9. Direct determination of resonance energy transfer in photolyase: structural alignment for the functional state.

    Science.gov (United States)

    Tan, Chuang; Guo, Lijun; Ai, Yuejie; Li, Jiang; Wang, Lijuan; Sancar, Aziz; Luo, Yi; Zhong, Dongping

    2014-11-13

    Photoantenna is essential to energy transduction in photoinduced biological machinery. A photoenzyme, photolyase, has a light-harvesting pigment of methenyltetrahydrofolate (MTHF) that transfers its excitation energy to the catalytic flavin cofactor FADH¯ to enhance DNA-repair efficiency. Here we report our systematic characterization and direct determination of the ultrafast dynamics of resonance energy transfer from excited MTHF to three flavin redox states in E. coli photolyase by capturing the intermediates formed through the energy transfer and thus excluding the electron-transfer quenching pathway. We observed 170 ps for excitation energy transferring to the fully reduced hydroquinone FADH¯, 20 ps to the fully oxidized FAD, and 18 ps to the neutral semiquinone FADH(•), and the corresponding orientation factors (κ(2)) were determined to be 2.84, 1.53 and 1.26, respectively, perfectly matching with our calculated theoretical values. Thus, under physiological conditions and over the course of evolution, photolyase has adopted the optimized orientation of its photopigment to efficiently convert solar energy for repair of damaged DNA.

  10. Overview of double dosimetry procedures for the determination of the effective dose to the interventional radiology staff

    International Nuclear Information System (INIS)

    Jaervinen, H.; Buls, N.; Clerinx, P.; Jansen, J.; Miljanic, S.; Nikodemova, D.; Ranogajec-Komor, M.; D'Errico, F.

    2008-01-01

    In interventional radiology, for an accurate determination of effective dose to the staff, measurements with two dosemeters have been recommended, one located above and one under the protective apron. Such 'double dosimetry' practices and the algorithms used for the determination of effective dose were reviewed in this study by circulating a questionnaire and by an extensive literature search. The results indicated that regulations for double dosimetry almost do not exist and there is no firm consensus on the most suitable calculation algorithms. The calculation of effective dose is mainly based on the single dosemeter measurements, in which either personal dose equivalent, directly, (dosemeter below the apron) or a fraction of personal dose equivalent (dosemeter above the apron) is taken as an assessment of effective dose. The most recent studies suggest that there might not be just one double dosimetry algorithm that would be optimum for all interventional radiology procedures. Further investigations in several critical configurations of interventional radiology procedures are needed to assess the suitability of the proposed algorithms. (authors)

  11. RF plasma parameter determination by a Langmuir multipoint double probe array

    International Nuclear Information System (INIS)

    Rojas-Olmedo, I A; López-Callejas, R; De la Piedad-Beneitez, A; Valencia-Alvarado, R; Peña-Eguiluz, R; Mercado-Cabrera, A; Barocio, S R; Muñoz-Castro, A E; Rodríguez-Méndez, B G

    2012-01-01

    A multipoint double Langmuir (MDL) probe system, which is exempt from interference, has been designed and assembled to be applied to an RF plasma. The system provides the measurement of fundamental plasma parameters such as density, temperature, plasma potential, etc. on the basis of the Bohm Approximation Theory and the Orbital Movement Limit. Thus, one pair of the MDL system is selected so as to consider the right plasma parameters within the prevailing pressure-power intervals. Both the hardware and software of the system have been applied to the modification of material properties by means of the PIII process.

  12. Determination of aortic compliance from magnetic resonance images using an automatic active contour model

    International Nuclear Information System (INIS)

    Krug, Roland; Boese, Jan M; Schad, Lothar R

    2003-01-01

    The possibility of monitoring changes in aortic elasticity in humans has important applications for clinical trials because it estimates the efficacy of plaque-reducing therapies. The elasticity is usually quantified by compliance measurements. Therefore, the relative temporal change in the vessel cross-sectional area throughout the cardiac cycle has to be determined. In this work we determined and compared the compliance between three magnetic resonance (MR) methods (FLASH, TrueFISP and pulse-wave). Since manual outlining of the aortic wall area is a very time-consuming process and depends on an operator's variability, an algorithm for the automatic segmentation of the artery wall from MR images through the entire heart cycle is presented. The reliable detection of the artery cross-sectional area over the whole heart cycle was possible with a relative error of about 1%. Optimizing the temporal resolution to 60 ms we obtained a relative error in compliance of about 7% from TrueFISP (1.0 x 1.0 x 10 mm 3 , signal-to-noise ratio (SNR) > 12) and FLASH (0.7 x 0.7 x 10 mm 3 , SNR > 12) measurements in volunteers. Pulse-wave measurements yielded an error of more than 9%. In a study of ten volunteers, a compliance between C = 3 x 10 -5 Pa -1 and C = 8 x 10 -5 Pa -1 was determined, depending on age. The results of the TrueFISP and the pulse-wave measurements agreed very well with one another (confidence interval of 1 x 10 -5 Pa -1 ) while the results of the FLASH method more clearly deviated from the TrueFISP and pulse-wave (confidence interval of more than 2 x 10 -5 Pa -1 )

  13. Tuning piezoresistive transduction in nanomechanical resonators by geometrical asymmetries

    Energy Technology Data Exchange (ETDEWEB)

    Llobet, J.; Sansa, M.; Lorenzoni, M.; Pérez-Murano, F., E-mail: francesc.perez@csic.es [Institut de Microelectrònica de Barcelona (IMB-CNM CSIC), Campus UAB, 08193 Bellaterra (Spain); Borrisé, X. [Institut Català de Nanociència i Nanotecnologia (ICN2), Campus UAB, 08193 Bellaterra Spain (Spain); San Paulo, A. [Instituto de Microelectrónica de Madrid (IMM-CSIC), 28760 Tres Cantos, Madrid (Spain)

    2015-08-17

    The effect of geometrical asymmetries on the piezoresistive transduction in suspended double clamped beam nanomechanical resonators is investigated. Tapered silicon nano-beams, fabricated using a fast and flexible prototyping method, are employed to determine how the asymmetry affects the transduced piezoresistive signal for different mechanical resonant modes. This effect is attributed to the modulation of the strain in pre-strained double clamped beams, and it is confirmed by means of finite element simulations.

  14. GEM-loaded magnetic albumin nanospheres modified with cetuximab for simultaneous targeting, magnetic resonance imaging, and double-targeted thermochemotherapy of pancreatic cancer cells

    Directory of Open Access Journals (Sweden)

    Wang L

    2015-03-01

    Full Text Available Ling Wang,1 Yanli An,2 Chenyan Yuan,3 Hao Zhang,2 Chen Liang,2 Fengan Ding,2 Qi Gao,1 Dongsheng Zhang4 1Department of Ultrasonography, Zhong Da Hospital, Medical School, Southeast University, Nanjing, People’s Republic of China; 2Medical School, Southeast University, Nanjing, People’s Republic of China; 3Department of Clinical Laboratory, Zhong Da Hospital, Medical School, Southeast University, Nanjing, People’s Republic of China; 4Jiangsu Key Laboratory for Biomaterials and Devices, Medical School, Southeast University, Nanjing, People’s Republic of China Background: Targeted delivery is a promising strategy to improve the diagnostic imaging and therapeutic effect of cancers. In this paper, novel cetuximab (C225-conjugated, gemcitabine (GEM-containing magnetic albumin nanospheres (C225-GEM/MANs were fabricated and applied as a theranostic nanocarrier to conduct simultaneous targeting, magnetic resonance imaging (MRI, and double-targeted thermochemotherapy against pancreatic cancer cells. Methods: Fe3O4 nanoparticles (NPs and GEM co-loaded albumin nanospheres (GEM/MANs were prepared, and then C225 was further conjugated to synthesize C225-GEM/MANs. Their morphology, mean particle size, GEM encapsulation ratio, specific cell-binding ability, and thermal dynamic profiles were characterized. The effects of discriminating different EGFR-expressing pancreatic cancer cells (AsPC-1 and MIA PaCa-2 and monitoring cellular targeting effects were assessed by targeted MRI. Lastly, the antitumor efficiency of double/C225/magnetic-targeted and nontargeted thermochemotherapy was compared with chemotherapy alone using 3-(4, 5-dimethyl-2-thiazolyl-2,5-diphenyl-2H-tetrazolium bromide (MTT and flow cytometry (FCM assay. Results: When treated with targeted nanospheres, AsPC-1 cells showed a significantly less intense MRI T2 signal than MIA PaCa-2 cells, while both cells had similar signal strength when incubated with nontargeted nanospheres. T2 signal

  15. Magnetic Resonance Imaging of the Ovaries of Healthy Women: Determination of Normal Values

    International Nuclear Information System (INIS)

    Hauth, E.A.M.; Jaeger, H.J.; Libera, H.; Lange, S.; Forsting, M.

    2006-01-01

    Purpose: To establish normal values for the volume and maximal diameter of ovaries and ovarian follicles and for the number of ovarian follicles in magnetic resonance imaging (MRI) based on menstrual cycle phase and age. Material and Methods: We performed MRI of the pelvis on 100 healthy women. Volume of the ovaries and largest ovarian follicles and the number of ovarian follicles were determined by menstrual cycle phase and age. Results: The mean volume of the ovaries significantly increased with age and reached its peak between 31 and 40 years, and subsequently decreased. The mean volume of the largest ovarian follicles also significantly increased with age to reach its peak at 41-50 years. The highest mean numbers of ovarian follicles were found at 20-40 years. When the volumes of ovaries and of the largest ovarian follicles, and the number of ovarian follicles were compared between the first and second phase of the menstrual cycle, no significant differences were found. Conclusion: The volume and maximal diameter of ovaries and ovarian follicles and the number of ovarian follicles differ significantly with age, but not between the two phases of the menstrual cycle. Knowledge of MRI-related normal values can be expected to aid the early identification of ovarian pathologies

  16. Functional magnetic resonance imaging to determine hemispheric language dominance prior to carotid endarterectomy.

    Science.gov (United States)

    Smits, M; Wieberdink, R G; Bakker, S L M; Dippel, D W J

    2011-04-01

    We describe a left-handed patient with transient aphasia and bilateral carotid stenosis. Computed tomography (CT) arteriography showed a 90% stenosis of the right and 30% stenosis of the left internal carotid artery. Head CT and magnetic resonance imaging (MRI) of the brain showed no recent ischemic changes. As only the symptomatic side would require surgical intervention, and because hemispheric dominance for language in left-handed patients may be either left or right sided, a preoperative assessment of hemispheric dominance was required. We used functional MRI to determine hemispheric dominance for language and hence to establish the indication for carotid endarterectomy surgery. Functional MRI demonstrated right hemispheric dominance for language and right-sided carotid endarterectomy was performed. We propose that the clinical use of functional MRI as a noninvasive imaging technique for the assessment of hemispheric language dominance may be extended to the assessment of hemispheric language dominance prior to carotid endarterectomy. Copyright © 2010 by the American Society of Neuroimaging.

  17. Trace determination of 90Sr and 89Sr in environmental samples by collinear resonance ionization spectroscopy

    International Nuclear Information System (INIS)

    Lantzsch, J.; Bushaw, B. A.; Bystrow, V. A.; Herrmann, G.; Kluge, H.-J.; Niess, S.; Otten, E. W.; Passler, G.; Schwalbach, R.; Schwarz, M.; Stenner, J.; Trautmann, N.; Wendt, K.; Yushkevich, Y. V.; Zimmer, K.

    1995-01-01

    Collinear resonance ionization spectroscopy has been developed as a sensitive technique for fast trace detection of 90 Sr and 89 Sr in the environment. A detection limit for 90 Sr of 10 7 atoms in the presence of 10 17 atoms in the presence of 10 17 atoms of stable Strontium has been achieved, while the applicability of the method has been demonstrated on real world samples. After collection and chemical separation, strontium is surface ionized, accelerated to 33keV and mass separated. The ions are neutralized and the emerging fast atoms interact with an argon ion laser beam (γ=364 nm) in a quasi-collinear geometry. Optical excitation starts from the long-lived 5s4d 3 D2 state of strontium, which is populated in the charge exchange process, and the fast atoms are selectively excited into the high-lying 5s23f 3 F3 Rydberg state. The Rydberg-atoms are subsequently field-ionized and detected by a channeltron detector after energy selection. The described method was successfully used to determine the 90 Sr-content in air samples collected near Munich during the Chernobyl reactor accident in April 1986

  18. Determining the Level of the Dural Sac Tip: Magnetic Resonance Imaging in an Adult Population

    International Nuclear Information System (INIS)

    Binokay, F.; Akgul, E.; Bicakci, K.; Soyupak, S.; Aksungur, E.; Sertdemir, Y.

    2006-01-01

    Purpose: To determine the variation in the location of the dural sac (DS) in a living adult population and to correlate this position with age and sex. Material and Methods: T2-weighted, midline, sagittal, spin-echo magnetic resonance imaging (MRI) studies of 743 patients were assessed to identify the tip of the DS. This location was recorded in relation to the upper, middle, or lower third of the adjacent vertebral body or the adjacent intervertebral disk. Results: Frequency distribution for levels of termination of the DS on MRI demonstrated that the end of the DS was usually located at the upper one-third of S2 (25.2%). The mean level in females was also the upper one-third of S2 (26.5%) and in males the lower one-third of S2 (24.1%). The overall mean DS position was mostly at the upper one-third of S2. No significant differences in DS position were seen between male and female patients or with increasing age. Conclusion: It is important to know the possible range for the termination level of the DS when performing caudal anesthesia and craniospinal irradiation in some clinical situations. The distribution of DS location in a large adult population was shown to range from the L5-S1 intervertebral disk to the upper third of S3 vertebrae

  19. Temperature dependence of the cosphi conductance in Josephson tunnel junctions determined from plasma resonance experiments

    International Nuclear Information System (INIS)

    Pedersen, N.F.; Soerensen, O.H.; Mygind, J.

    1978-01-01

    The microwave response at 9 GHz of Sn-O-Sn tunnel-junction current biased at zero dc voltage has been measured just below the critical temperature T/sub c/ of the Sn films. The temperature dependence of the cosphi conductance is determined from the resonant response at the junction plasma frequency f/sub p/ as the temperature is decreased from T/sub c/. We used three different schemes for observation of the plasma oscillations: (a) second-harmonic generation (excitation at approx. 4.5 GHz, f/sub p/ approx. 4.5 GHz); (b) mixing (excitations at approx. 9 and approx. 18 GHz, f/sub p/ approx. 9 GHz); (c) parametric half-harmonic oscillation (excitation at approx. 18 GHz, f/sub p/ approx. 9 GHz). Measurements were possible in two temperature intervals; 0.994 or = T/T/sub c/ > or = 0.930, with the result that as the temperature was decreased the cosphi amplitude first increased from about zero to positive values and then at lower temperatures decreased approaching -1 at the lowest temperatures of the experiment

  20. Structure determination of human Lck unique and SH3 domains by nuclear magnetic resonance spectroscopy

    Directory of Open Access Journals (Sweden)

    Willbold Dieter

    2003-05-01

    Full Text Available Abstract Background Protein tyrosine kinases are involved in signal transduction pathways that regulate cell growth, differentiation, activation and transformation. Human lymphocyte specific kinase (Lck is a 56 kDa protein involved in T-cell- and IL2-receptor signaling. Three-dimensional structures are known for SH3, SH2 and kinase domains of Lck as well as for other tyrosine kinases. No structure is known for the unique domain of any Src-type tyrosine kinase. Results Lck(1–120 comprising unique and SH3 domains was structurally investigated by nuclear magnetic resonance spectroscopy. We found the unique domain, in contrast to the SH3 part, to have basically no defined structural elements. The solution structure of the SH3 part could be determined with very high precision. It does not show significant differences to Lck SH3 in the absence of the unique domain. Minor differences were observed to the X-ray structure of Lck SH3. Conclusion The unique domain of Lck does not contain any defined structure elements in the absence of ligands and membranes. Presence of the unique domain is not relevant to the three-dimensional structure of the Lck SH3 domain.

  1. Determination of the resonance parameters for 232Th from high resolution transmission and capture measurements at GELINA

    International Nuclear Information System (INIS)

    Brusegan, A.; Schillebeeckx, P.; Lobo, G.; Borella, A.; Volev, K.; Janeva, N.

    2003-01-01

    To deduce the resonance parameters for 232 Th in the resolved resonance region, high resolution transmission and capture measurements are being performed. The measurements are performed at the Time-Of-Flight facility GELINA. A comparison of experimental data resulting from capture (top) and transmission (bottom) are shown. The transmission measurements are performed at a 50 m flight path. The neutron are detected with a 0.25' thick lithium glass (NE912) placed in an Al sphere and viewed by a 5' EMI KQB photomultiplier orthogonal to the neutron beam axis. The injection of a stabilised light pulse in the detector during the measurements provided an efficient tool to control to better than 1% the gain of the entire electronics. The experimental set-up includes a sample-changer, placed at 23 m from the neutron source, which is driven by the acquisition system. The determination of the flight path length, was based on transmission of the 6.673 eV resonance of 238 U. We summarise, for the different energy regions of interest, the scheduled measurement conditions: the operation frequency of the accelerator and the target thickness. A simultaneous analysis of the data using REFIT will result in the resonance parameters from 0 to 4 keV. We show the result of a resonance shape analysis for the resonances at 21.8 and 23.5 eV. The resulting resonance parameters are important for the energy calibration and normalisation of the capture measurements in both the resolved and unresolved resonance region. The capture measurements are completed and were performed at a 60 m flight path. The sample consisted of a metallic natural thorium disc of 8 cm diameter and 1.0 mm thick, corresponding to a thickness of 3.176 10 -3 at/b. The neutron flux was measured with an ionisation chamber loaded with three back-to-back layers of about 40 μg/cm 2 10 B. The gamma rays, originating from the 232 Th(n,γ) reaction, were detected by four C 6 D 6 -based liquid scintillators (NE230) placed

  2. Determination of effective dose for workers hemodynamics service using double dosimetry

    International Nuclear Information System (INIS)

    Ruiz Lopez, M. A.; Lobato Munoz, M.; Jodar Lopez, C. A.; Ramirez Ros, J. C.; Jerez Sainz, M. I.; Pamos Urena, M.; Carrasco Rodriguez, J. L.

    2013-01-01

    The use of an additional dosimeter at the level of the neck above the lead apron we can provide an indication of the dose in the head (the Crystal dose). In addition, it is possible to combine the two readings of the dosimeter to provide an improved estimate of the effective dose. In the hemodynamics service of our Hospital we have maintained a worker for 3 years with the double dosimetry read monthly. With the readings from these dosimeters will do following algorithms, several estimates of the effective dose to see if, with working conditions that occur in this service, it would be necessary to extend this practice to the rest of the workers to get a better estimation of effective dose. (Author)

  3. Observation of strongly forbidden solid effect dynamic nuclear polarization transitions via electron-electron double resonance detected NMR

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Albert A.; Corzilius, Björn; Haze, Olesya; Swager, Timothy M.; Griffin, Robert G., E-mail: rgg@mit.edu [Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2013-12-07

    We present electron paramagnetic resonance experiments for which solid effect dynamic nuclear polarization transitions were observed indirectly via polarization loss on the electron. This use of indirect observation allows characterization of the dynamic nuclear polarization (DNP) process close to the electron. Frequency profiles of the electron-detected solid effect obtained using trityl radical showed intense saturation of the electron at the usual solid effect condition, which involves a single electron and nucleus. However, higher order solid effect transitions involving two, three, or four nuclei were also observed with surprising intensity, although these transitions did not lead to bulk nuclear polarization—suggesting that higher order transitions are important primarily in the transfer of polarization to nuclei nearby the electron. Similar results were obtained for the SA-BDPA radical where strong electron-nuclear couplings produced splittings in the spectrum of the indirectly observed solid effect conditions. Observation of high order solid effect transitions supports recent studies of the solid effect, and suggests that a multi-spin solid effect mechanism may play a major role in polarization transfer via DNP.

  4. IR-UV double resonance spectroscopic investigation of phenylacetylene-alcohol complexes. Alkyl group induced hydrogen bond switching.

    Science.gov (United States)

    Singh, Prashant Chandra; Patwari, G Naresh

    2008-06-12

    The electronic transitions of phenylacetylene complexes with water and trifluoroethanol are shifted to the blue, while the corresponding transitions for methanol and ethanol complexes are shifted to the red relative to the phenylacetylene monomer. Fluorescence dip infrared (FDIR) spectra in the O-H stretching region indicate that, in all the cases, phenylacetylene is acting as a hydrogen bond acceptor to the alcohols. The FDIR spectrum in the acetylenic C-H stretching region shows Fermi resonance bands for the bare phenylacetylene, which act as a sensitive tool to probe the intermolecular structures. The FDIR spectra reveal that water and trifluoroethanol interact with the pi electron density of the acetylene C-C triple bond, while methanol and ethanol interact with the pi electron density of the benzene ring. It can be inferred that the hydrogen bonding acceptor site on phenylacetylene switches from the acetylene pi to the benzene pi with lowering in the partial charge on the hydrogen atom of the OH group. The most significant finding is that the intermolecular structures of water and methanol complexes are notably distinct, which, to the best of our knowledge, this is first such observation in the case of complexes of substituted benzenes.

  5. Interplay of activation kinetics and the derivative conductance determines resonance properties of neurons

    Science.gov (United States)

    Pena, Rodrigo F. O.; Ceballos, Cesar C.; Lima, Vinicius; Roque, Antonio C.

    2018-04-01

    In a neuron with hyperpolarization activated current (Ih), the correct input frequency leads to an enhancement of the output response. This behavior is known as resonance and is well described by the neuronal impedance. In a simple neuron model we derive equations for the neuron's resonance and we link its frequency and existence with the biophysical properties of Ih. For a small voltage change, the component of the ratio of current change to voltage change (d I /d V ) due to the voltage-dependent conductance change (d g /d V ) is known as derivative conductance (GhDer). We show that both GhDer and the current activation kinetics (characterized by the activation time constant τh) are mainly responsible for controlling the frequency and existence of resonance. The increment of both factors (GhDer and τh) greatly contributes to the appearance of resonance. We also demonstrate that resonance is voltage dependent due to the voltage dependence of GhDer. Our results have important implications and can be used to predict and explain resonance properties of neurons with the Ih current.

  6. UV-Vis Ratiometric Resonance Synchronous Spectroscopy for Determination of Nanoparticle and Molecular Optical Cross Sections.

    Science.gov (United States)

    Nettles, Charles B; Zhou, Yadong; Zou, Shengli; Zhang, Dongmao

    2016-03-01

    Demonstrated herein is a UV-vis Ratiometric Resonance Synchronous Spectroscopic (R2S2, pronounced as "R-two-S-two" for simplicity) technique where the R2S2 spectrum is obtained by dividing the resonance synchronous spectrum of a NP-containing solution by the solvent resonance synchronous spectrum. Combined with conventional UV-vis measurements, this R2S2 method enables experimental quantification of the absolute optical cross sections for a wide range of molecular and nanoparticle (NP) materials that range optically from pure photon absorbers or scatterers to simultaneous photon absorbers and scatterers, simultaneous photon absorbers and emitters, and all the way to simultaneous photon absorbers, scatterers, and emitters in the UV-vis wavelength region. Example applications of this R2S2 method were demonstrated for quantifying the Rayleigh scattering cross sections of solvents including water and toluene, absorption and resonance light scattering cross sections for plasmonic gold nanoparticles, and absorption, scattering, and on-resonance fluorescence cross sections for semiconductor quantum dots (Qdots). On-resonance fluorescence quantum yields were quantified for the model molecular fluorophore Eosin Y and fluorescent Qdots CdSe and CdSe/ZnS. The insights and methodology presented in this work should be of broad significance in physical and biological science research that involves photon/matter interactions.

  7. Energetics of endurance exercise in young horses determined by nuclear magnetic resonance metabolomics

    Directory of Open Access Journals (Sweden)

    Margaux Marie-Hélène, Olivia Luck

    2015-07-01

    Full Text Available Long-term endurance exercise severely affects metabolism in both human and animal athletes resulting in serious risk of metabolic disorders during or after competition. Young horses (up to 6 years old can compete in races up to 90 km despite limited scientific knowledge of energetic metabolism responses to long distance exercise in these animals. The hypothesis of this study was that there would be a strong effect of endurance exercise on the metabolomic profiles of young horses and that the energetic metabolism response in young horses would be different from that of more experienced horses. Metabolomic profiling is a powerful method that combines Nuclear magnetic resonance (NMR spectrometry with supervised orthogonal projection on latent structure (OPLS statistical analysis. 1H-NMR spectra were obtained from plasma samples drawn from young horses (before and after competition. The spectra obtained before and after the race from the same horse (92 samples were compared using OPLS. The statistical parameters showed the robustness of the model (R2Y=0.947, Q2Y=0.856 and CV-ANOVA p-value < 0.001. For confirmation of the predictive value of the model, a test set of 104 sample spectra were projected by the model, which provided perfect predictions as the area under the receiving-operator curve was 1. The metabolomic profile determined with the OPLS model showed that glycemia after the race was lower than glycemia before the race, despite the involvement of lipid and protein catabolism. An OPLS model was calculated to compare spectra obtained on plasma taken after the race from 6-year-old horses and from experienced horses (cross-validated ANOVA p-value < 0.001. The comparison of metabolomic profiles in young horses to those from experienced horses showed that experienced horses maintained their glycemia with higher levels of lactate and a decrease of plasma lipids after the race.

  8. Simultaneous determination of five active compounds in chimonanthus nitens by double-development HPTLC and scanning densitometry

    Directory of Open Access Journals (Sweden)

    Zhou Bin

    2012-05-01

    Full Text Available Abstract Background Chimonanthus nitens (family Calycanthaceae, Shanlamei in Chinese, is an unique species in China. The extract of dried leaves of Chimonanthus nitens has anti-inflammatory, antipyretic and antitussive effects. Terpenes, coumarins, and flavonoids are usually regarded as the main active components. Therefore, simultaneous determination of these compounds is very important to control the quality of Chimonanthus nitens. Results A double-development TLC method was developed for simultaneous analysis of five compounds in Chimonanthus nitens. The chromatography was performed on silica gel 60 plate with chloroform-methanol (9∶1, v/v and petroleum ether-ethyl acetate (10∶1, v/v as mobile phase for twice development. Their characteristic TLC profiles were observed under UV light at 365 nm and the bands were then revealed by reaction with 1% vanillin-H2SO4 solution. Quantification of three monoterpenes was achieved by densitometry at 545 nm (β-caryophyllene or 606 nm (cineole and linalool. Two coumarins (scopoletin and scoparone were determined by densitometry at 340 nm with filter wavelength of 370 nm. The investigated compounds had good linearity (R2 >0.99 within test ranges. Conclusions The developed double-development TLC method is helpful to control the quality of Chimonanthus nitens, which is simple and accurate.

  9. Gadolinium-Doped Gallic Acid-Zinc/Aluminium-Layered Double Hydroxide/Gold Theranostic Nanoparticles for a Bimodal Magnetic Resonance Imaging and Drug Delivery System

    Science.gov (United States)

    Sani Usman, Muhammad; Hussein, Mohd Zobir; Fakurazi, Sharida; Ahmad Saad, Fathinul Fikri

    2017-01-01

    We have developed gadolinium-based theranostic nanoparticles for co-delivery of drug and magnetic resonance imaging (MRI) contrast agent using Zn/Al-layered double hydroxide as the nanocarrier platform, a naturally occurring phenolic compound, gallic acid (GA) as therapeutic agent, and Gd(NO3)3 as diagnostic agent. Gold nanoparticles (AuNPs) were grown on the system to support the contrast for MRI imaging. The nanoparticles were characterized using techniques such as Hi-TEM, XRD, ICP-ES. Kinetic release study of the GA from the nanoparticles showed about 70% of GA was released over a period of 72 h. The in vitro cell viability test for the nanoparticles showed relatively low toxicity to human cell lines (3T3) and improved toxicity on cancerous cell lines (HepG2). A preliminary contrast property test of the nanoparticles, tested on a 3 Tesla MRI machine at various concentrations of GAGZAu and water (as a reference) indicates that the nanoparticles have a promising dual diagnostic and therapeutic features to further develop a better future for clinical remedy for cancer treatment. PMID:28858229

  10. Assessment of amide I spectroscopic maps for a gas-phase peptide using IR-UV double-resonance spectroscopy and density functional theory calculations

    Energy Technology Data Exchange (ETDEWEB)

    Carr, J. K.; Roy, S.; Skinner, J. L. [Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin, Madison, Wisconsin 53706 (United States); Zabuga, A. V.; Rizzo, T. R. [Laboratoire de Chimie Physique Moleculaire, Ecole Polytechnique Fédérale de Lausanne, EPFL SB ISIC LCPM, Station 6, CH-1015 Lausanne (Switzerland)

    2014-06-14

    The spectroscopy of amide I vibrations has become a powerful tool for exploring protein structure and dynamics. To help with spectral interpretation, it is often useful to perform molecular dynamics (MD) simulations. To connect spectroscopic experiments to simulations in an efficient manner, several researchers have proposed “maps,” which relate observables in classical MD simulations to quantum spectroscopic variables. It can be difficult to discern whether errors in the theoretical results (compared to experiment) arise from inaccuracies in the MD trajectories or in the maps themselves. In this work, we evaluate spectroscopic maps independently from MD simulations by comparing experimental and theoretical spectra for a single conformation of the α-helical model peptide Ac-Phe-(Ala){sub 5}-Lys-H{sup +} in the gas phase. Conformation-specific experimental spectra are obtained for the unlabeled peptide and for several singly and doubly {sup 13}C-labeled variants using infrared-ultraviolet double-resonance spectroscopy, and these spectra are found to be well-modeled by density functional theory (DFT) calculations at the B3LYP/6-31G** level. We then compare DFT results for the deuterated and {sup 13}C{sup 18}O-labeled peptide with those from spectroscopic maps developed and used previously by the Skinner group. We find that the maps are typically accurate to within a few cm{sup −1} for both frequencies and couplings, having larger errors only for the frequencies of terminal amides.

  11. 2 µm high-power dissipative soliton resonance in a compact σ-shaped Tm-doped double-clad fiber laser

    Science.gov (United States)

    Du, Tuanjie; Li, Weiwei; Ruan, Qiujun; Wang, Kaijie; Chen, Nan; Luo, Zhengqian

    2018-05-01

    We report direct generation of a high-power, large-energy dissipative soliton resonance (DSR) in a 2 µm Tm-doped double-clad fiber laser. A compact σ-shaped cavity is formed by a fiber Bragg grating and a 10/90 fiber loop mirror (FLM). The 10/90 FLM is not only used as an output mirror, but also acts as a nonlinear optical loop mirror for initiating mode locking. The mode-locked laser can deliver high-power, nanosecond DSR pulses at 2005.9 nm. We further perform a comparison study of the effect of the FLM’s loop length on the mode-locking threshold, peak power, pulse energy, and optical spectrum of the DSR pulses. We achieve a maximum average output power as high as 1.4 W, a maximum pulse energy of 353 nJ, and a maximum peak power of 84 W. This is, to the best of our knowledge, the highest power for 2 µm DSR pulses obtained in a mode-locked fiber laser.

  12. Assessment of amide I spectroscopic maps for a gas-phase peptide using IR-UV double-resonance spectroscopy and density functional theory calculations

    International Nuclear Information System (INIS)

    Carr, J. K.; Roy, S.; Skinner, J. L.; Zabuga, A. V.; Rizzo, T. R.

    2014-01-01

    The spectroscopy of amide I vibrations has become a powerful tool for exploring protein structure and dynamics. To help with spectral interpretation, it is often useful to perform molecular dynamics (MD) simulations. To connect spectroscopic experiments to simulations in an efficient manner, several researchers have proposed “maps,” which relate observables in classical MD simulations to quantum spectroscopic variables. It can be difficult to discern whether errors in the theoretical results (compared to experiment) arise from inaccuracies in the MD trajectories or in the maps themselves. In this work, we evaluate spectroscopic maps independently from MD simulations by comparing experimental and theoretical spectra for a single conformation of the α-helical model peptide Ac-Phe-(Ala) 5 -Lys-H + in the gas phase. Conformation-specific experimental spectra are obtained for the unlabeled peptide and for several singly and doubly 13 C-labeled variants using infrared-ultraviolet double-resonance spectroscopy, and these spectra are found to be well-modeled by density functional theory (DFT) calculations at the B3LYP/6-31G** level. We then compare DFT results for the deuterated and 13 C 18 O-labeled peptide with those from spectroscopic maps developed and used previously by the Skinner group. We find that the maps are typically accurate to within a few cm −1 for both frequencies and couplings, having larger errors only for the frequencies of terminal amides

  13. Electric-dipole moment of CaF by molecular-beam, laser-rf, double-resonance study of Stark splittings

    International Nuclear Information System (INIS)

    Childs, W.J.; Goodman, L.S.; Nielsen, U.; Pfeufer, V.

    1984-01-01

    The electronic structure of diatomic molecules is much more complex for open-shell sytems (radicals) than for the normal closed-shell systems, and the development of an adequate theoretical understanding will require a substantial upgrading of experimental knowledge in both quality and quantity. The alkaline-earth monohalide family of radicals, with only a single electron outside closed-shell cores, would appear to be a logical starting point for such studies, and there has been a great increase in work in this area in the last few years in spite of the special difficulties of working with free radicals. As the work of measuring the vibrational and rotational structure of the electronic states has become more complete, attention has turned to study of the much weaker spin-rotation and hyperfine interactions. Within the last three years, these interactions have been studied systematically at high precision in the calcium monohalide family with the molecular-beam, laser-rf double-resonance technique. The same method has now been modified and extended to make possible measurement of the electric-dipole moments of these molecules through observation of the Stark splittings of radiofrequency transitions. It is hoped that when considered together, the several types of data will make it possible to understand the ground-state electronic wave functions of these molecules at least qualitatively. 2 figures

  14. Assessment of amide I spectroscopic maps for a gas-phase peptide using IR-UV double-resonance spectroscopy and density functional theory calculations

    Science.gov (United States)

    Carr, J. K.; Zabuga, A. V.; Roy, S.; Rizzo, T. R.; Skinner, J. L.

    2014-01-01

    The spectroscopy of amide I vibrations has become a powerful tool for exploring protein structure and dynamics. To help with spectral interpretation, it is often useful to perform molecular dynamics (MD) simulations. To connect spectroscopic experiments to simulations in an efficient manner, several researchers have proposed “maps,” which relate observables in classical MD simulations to quantum spectroscopic variables. It can be difficult to discern whether errors in the theoretical results (compared to experiment) arise from inaccuracies in the MD trajectories or in the maps themselves. In this work, we evaluate spectroscopic maps independently from MD simulations by comparing experimental and theoretical spectra for a single conformation of the α-helical model peptide Ac-Phe-(Ala)5-Lys-H+ in the gas phase. Conformation-specific experimental spectra are obtained for the unlabeled peptide and for several singly and doubly 13C-labeled variants using infrared-ultraviolet double-resonance spectroscopy, and these spectra are found to be well-modeled by density functional theory (DFT) calculations at the B3LYP/6-31G** level. We then compare DFT results for the deuterated and 13C18O-labeled peptide with those from spectroscopic maps developed and used previously by the Skinner group. We find that the maps are typically accurate to within a few cm−1 for both frequencies and couplings, having larger errors only for the frequencies of terminal amides. PMID:24929378

  15. Gadolinium-Doped Gallic Acid-Zinc/Aluminium-Layered Double Hydroxide/Gold Theranostic Nanoparticles for a Bimodal Magnetic Resonance Imaging and Drug Delivery System.

    Science.gov (United States)

    Sani Usman, Muhammad; Hussein, Mohd Zobir; Fakurazi, Sharida; Masarudin, Mas Jaffri; Ahmad Saad, Fathinul Fikri

    2017-08-31

    We have developed gadolinium-based theranostic nanoparticles for co-delivery of drug and magnetic resonance imaging (MRI) contrast agent using Zn/Al-layered double hydroxide as the nanocarrier platform, a naturally occurring phenolic compound, gallic acid (GA) as therapeutic agent, and Gd(NO₃)₃ as diagnostic agent. Gold nanoparticles (AuNPs) were grown on the system to support the contrast for MRI imaging. The nanoparticles were characterized using techniques such as Hi-TEM, XRD, ICP-ES. Kinetic release study of the GA from the nanoparticles showed about 70% of GA was released over a period of 72 h. The in vitro cell viability test for the nanoparticles showed relatively low toxicity to human cell lines (3T3) and improved toxicity on cancerous cell lines (HepG2). A preliminary contrast property test of the nanoparticles, tested on a 3 Tesla MRI machine at various concentrations of GAGZAu and water (as a reference) indicates that the nanoparticles have a promising dual diagnostic and therapeutic features to further develop a better future for clinical remedy for cancer treatment.

  16. Gold Nanoclusters@Ru(bpy)₃²⁺-Layered Double Hydroxide Ultrathin Film as a Cathodic Electrochemiluminescence Resonance Energy Transfer Probe.

    Science.gov (United States)

    Yu, Yingchang; Lu, Chao; Zhang, Meining

    2015-08-04

    Herein, it is the first report that a cathodic electrochemiluminescence (ECL) resonance energy transfer (ERET) system is fabricated by layer-by-layer (LBL) electrostatic assembly of CoAl layered double hydroxide (LDH) nanosheets with a mixture of blue BSA-gold nanoclusters (AuNCs) and Ru(bpy)3(2+) (denoted as AuNCs@Ru) on an Au electrode. The possible ECL mechanism indicates that the appearance of CoAl-LDH nanosheets generates a long-range stacking order of the AuNCs@Ru on an Au electrode, facilitating the occurrence of the ERET between BSA-AuNC donors and Ru(bpy)3(2+) acceptors on the as-prepared AuNCs@Ru-LDH ultrathin films (UTFs). Furthermore, it is observed that the cathodic ECL intensity can be quenched efficiently in the presence of 6-mercaptopurine (6-MP) in a linear range of 2.5-100 nM with a detection limit of 1.0 nM. On the basis of these interesting phenomena, a facile cathodic ECL sensor has successfully distinguished 6-MP from other thiol-containing compounds (e.g., cysteine and glutathione) in human serum and urine samples. The proposed sensing scheme opens a way for employing the layered UTFs as a platform for the cathodic ECL of Ru(bpy)3(2+).

  17. Application of resonant backscattering spectrometry for determination of pore structure changes

    Energy Technology Data Exchange (ETDEWEB)

    Paszti, F. E-mail: paszti@rmki.kfki.hu; Szilagyi, E.; Manuaba, A.; Battistig, G

    2000-03-01

    In the present work slightly oxidised porous silicon samples of columnar type were investigated by resonant elastic scattering using the 3045 keV resonance in the {sup 16}O({alpha},{alpha}){sup 16}O reaction. If the incident energy is slightly above the resonance energy, a characteristic peak appears in the energy spectra of the backscattered particles. In porous material the individual ions travel fluctuating distance in pores, hence, the peak width depends on the structure of the sample. When changing the direction of the analysing beam to the sample, the width of the resonance peak changes in a special way characterising the angular distribution of the pore walls. This resonance method was applied to columnar type porous Si samples implanted by 4 MeV N ions at various tilt angles and fluences. It was shown that the beam tilts the pore walls by an angle proportional to the fluence and the sine of the angle between the beam and the pore walls. Meantime, the angular divergence of the pore walls also increases. The underlying mechanism is briefly discussed.

  18. Determination of anisotropy constants of protein encapsulated iron oxide nanoparticles by electron magnetic resonance

    International Nuclear Information System (INIS)

    Li Hongyan; Klem, Michael T.; Sebby, Karl B.; Singel, David J.; Young, Mark; Douglas, Trevor; Idzerda, Yves U.

    2009-01-01

    Angle-dependent electron magnetic resonance was performed on 4.9, 8.0, and 19 nm iron oxide nanoparticles encapsulated within protein capsids and suspended in water. Measurements were taken at liquid nitrogen temperature after cooling in a 1 T field to partially align the particles. The angle dependence of the shifts in the resonance field for the iron oxide nanoparticles (synthesized within Listeria-Dps, horse spleen ferritin, and cowpea chlorotic mottle virus) all show evidence of a uniaxial anisotropy. Using a Boltzmann distribution for the particles' easy-axis direction, we are able to use the resonance field shifts to extract a value for the anisotropy energy, showing that the anisotropy energy density increases with decreasing particle size. This suggests that surface anisotropy plays a significant role in magnetic nanoparticles of this size

  19. Determination of freeze-out conditions from fluctuations in the Hadron Resonance Gas model

    International Nuclear Information System (INIS)

    Alba, P; Alberico, W; Sarti, V Mantovani; Ratti, C; Bellwied, R; Bluhm, M; Nahrgang, M

    2015-01-01

    Fluctuations of conserved charges measured in Heavy-Ion Collisions (HICs) received increasing attention in recent years, because they are good candidates to explore the phase diagram of QCD matter. During the last year, net-electric charge and net-proton moments of multiplicities measured at RHIC have been published by the STAR collaboration, for a range of collision energies which spans a region of the phase diagram at finite chemical potential. Here we present a new freeze-out curve obtained using the Hadron Resonance Gas (HRG) model approach to fit these experimental data. The HRG model is modified in order to have a realistic description of the HICs: kinematic cuts, resonance feed-down and resonance regeneration are taken into account. Our result is in agreement with preliminary studies by the ALICE collaboration, and is supported by a recent lattice analysis of the same quantities. (paper)

  20. Determination of anisotropy constants of protein encapsulated iron oxide nanoparticles by electron magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Li Hongyan [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Center for Bio-Inspired Nanomaterials, Montana State University, Bozeman, MT 59717 (United States); Klem, Michael T.; Sebby, Karl B.; Singel, David J. [Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717 (United States); Center for Bio-Inspired Nanomaterials, Montana State University, Bozeman, MT 59717 (United States); Young, Mark [Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT 59717 (United States); Center for Bio-Inspired Nanomaterials, Montana State University, Bozeman, MT 59717 (United States); Douglas, Trevor [Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717 (United States); Center for Bio-Inspired Nanomaterials, Montana State University, Bozeman, MT 59717 (United States); Idzerda, Yves U. [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Center for Bio-Inspired Nanomaterials, Montana State University, Bozeman, MT 59717 (United States)], E-mail: Idzerda@montana.edu

    2009-02-15

    Angle-dependent electron magnetic resonance was performed on 4.9, 8.0, and 19 nm iron oxide nanoparticles encapsulated within protein capsids and suspended in water. Measurements were taken at liquid nitrogen temperature after cooling in a 1 T field to partially align the particles. The angle dependence of the shifts in the resonance field for the iron oxide nanoparticles (synthesized within Listeria-Dps, horse spleen ferritin, and cowpea chlorotic mottle virus) all show evidence of a uniaxial anisotropy. Using a Boltzmann distribution for the particles' easy-axis direction, we are able to use the resonance field shifts to extract a value for the anisotropy energy, showing that the anisotropy energy density increases with decreasing particle size. This suggests that surface anisotropy plays a significant role in magnetic nanoparticles of this size.

  1. New experimental determination of the neutronic resonance parameters of {sup 237}Np below 500 eV; Nouvelle determination experimentale des parametres de resonances neutroniques de {sup 237}Np en dessous de 500 eV

    Energy Technology Data Exchange (ETDEWEB)

    Gressier, V

    1999-10-01

    For studies of future nuclear reactors dedicated to nuclear waste transmutation, an improvement of the accuracy of the neutron radiative capture cross section of {sup 237}Np appears necessary. In the framework of a collaboration between the Commissariat a l'Energie atomique (CEA) and Institute for Reference Materials and Measurement (IRMM, Geel, Bergium), a new determination of the resonance parameters of {sup 237}Np has been performed. Two types of experiments are carried out at GELINA, the IRMM pulsed neutron source, using the time of flight method: a transmission experiment which is related to the neutron total cross section and a capture experiment which gives the neutron radiative capture cross section. The resonance parameters presented in this work are extracted from the transmission data between 0 and 500 eV with the least square code REFIT, using the Reich-Moore formalism. In parallel, the Doppler effect is investigated. The commonly used free gas model appears inadequate below 20 eV for neptunium dioxide at room temperature. By the use of the program DOPUSH, which calculates the Doppler broadening with a harmonic crystal model according to Lamb's theory, we are able to produce abetter fit of the experimental data for the resonances of {sup 237}Np in NpO{sub 2} at low energy or temperatures. In addition to the resonance parameters, a study of their mean value and distribution is included in this work. (authors)

  2. Experimental Determination of Bending Resonances of Millimeter Size PVF2 Cantilevers

    Directory of Open Access Journals (Sweden)

    David F. Thompson

    2003-07-01

    Full Text Available The polymer piezoelectric polvinylidene fluoride has found widespread use in sensors and actuators. The bending mode of piezoelectricity offers very high sensitivities and low mechanical input impedance, but has not been studied in as much detail for sensor applications. We report the dynamic electromechanical properties of millimeter size cantilevers made from electroded films of PVF2. All devices tested had a single polymer layer. Several resonances are found below 1 kHz and the experimentally observed resonance frequency dependence on cantilever thickness and length are seen to agree well with published models which take the properties of the electrodes into account. It is found that bending resonances are also modulated by the width of the cantilever. Therefore, though the length and thickness control the resonance frequency most strongly, the actual realized value can be fine-tuned by changing cantilever width and the electrode material and its thickness. Further, all resonances display high piezoelectric coupling coefficients (keff, ranging between 0.2 - 0.35. The data presented here will be extremely useful in the design of sensors and actuators for a number of applications, since the combination of millimeter size scales and high piezoelectric sensitivities in the low audio range can be realized with this marriage of polymeric materials and cantilever geometries. Such an array of sensors can be used in cochlear implant applications, and when integrated with a resonance interrogation circuit can be used for the detection of low frequency vibrations of large structures. If appropriate mass/elasticity sensitive layers are coated on the electrodes, such a sensor can be used for the detection of a wide range of chemicals and biochemicals.

  3. Determination of neutron resonance parameters of Neptunium 237 between 0 and 500 eV. The covariance matrices of statistical and of systematic origin, relating the resonance parameters, are also given; Determination des parametres des resonances neutroniques du neptunium 237, en dessous de 500eV, et obtention des matrices de covariances statistiques et systematiques entre les parametres de ces resonances

    Energy Technology Data Exchange (ETDEWEB)

    Lepretre, A.; Herault, N. [CEA Saclay, Dept. d' Astrophysique de Physique des Particules, de Physique Nucleaire et de l' Instrumentation Associee, 91- Gif sur Yvette (France); Brusegan, A.; Noguere, G.; Siegler, P. [Institut des Materiaux et des Metrologies - IRMM, Joint Research Centre, Gell (Belgium)

    2002-12-01

    This report is a follow up of the report CEA DAPNIA/SPHN-99-04T of Vincent Gressier. In the frame of a collaboration between the 'Commissariat a l'Energie Atomique (CEA)' and the Institute for Reference Materials and Measurement (IRMM, Geel, Belgique), the resonance parameters of neptunium 237 have been determined in the energy interval between 0 and 500 eV. These parameters have been obtained by using the Refit code in analysing simultaneously three transmission experiments. The covariance matrix of statistical origin is provided. A new method, based on various sensitivity studies is proposed for determining also the covariance matrix of systematic origin, relating the resonance parameters. From an experimental viewpoint, the study indicated that, with a large probability, the background spectrum has structure. A two dimensional profiler for the neutron density has been proved feasible. Such a profiler could, among others, demonstrate the existence of the structured background. (authors)

  4. Determination of Surface Potential and Electrical Double-Layer Structure at the Aqueous Electrolyte-Nanoparticle Interface

    Directory of Open Access Journals (Sweden)

    Matthew A. Brown

    2016-01-01

    Full Text Available The structure of the electrical double layer has been debated for well over a century, since it mediates colloidal interactions, regulates surface structure, controls reactivity, sets capacitance, and represents the central element of electrochemical supercapacitors. The surface potential of such surfaces generally exceeds the electrokinetic potential, often substantially. Traditionally, a Stern layer of nonspecifically adsorbed ions has been invoked to rationalize the difference between these two potentials; however, the inability to directly measure the surface potential of dispersed systems has rendered quantitative measurements of the Stern layer potential, and other quantities associated with the outer Helmholtz plane, impossible. Here, we use x-ray photoelectron spectroscopy from a liquid microjet to measure the absolute surface potentials of silica nanoparticles dispersed in aqueous electrolytes. We quantitatively determine the impact of specific cations (Li^{+}, Na^{+}, K^{+}, and Cs^{+} in chloride electrolytes on the surface potential, the location of the shear plane, and the capacitance of the Stern layer. We find that the magnitude of the surface potential increases linearly with the hydrated-cation radius. Interpreting our data using the simplest assumptions and most straightforward understanding of Gouy-Chapman-Stern theory reveals a Stern layer whose thickness corresponds to a single layer of water molecules hydrating the silica surface, plus the radius of the hydrated cation. These results subject electrical double-layer theories to direct and falsifiable tests to reveal a physically intuitive and quantitatively verified picture of the Stern layer that is consistent across multiple electrolytes and solution conditions.

  5. Determination of Surface Potential and Electrical Double-Layer Structure at the Aqueous Electrolyte-Nanoparticle Interface

    Science.gov (United States)

    Brown, Matthew A.; Abbas, Zareen; Kleibert, Armin; Green, Richard G.; Goel, Alok; May, Sylvio; Squires, Todd M.

    2016-01-01

    The structure of the electrical double layer has been debated for well over a century, since it mediates colloidal interactions, regulates surface structure, controls reactivity, sets capacitance, and represents the central element of electrochemical supercapacitors. The surface potential of such surfaces generally exceeds the electrokinetic potential, often substantially. Traditionally, a Stern layer of nonspecifically adsorbed ions has been invoked to rationalize the difference between these two potentials; however, the inability to directly measure the surface potential of dispersed systems has rendered quantitative measurements of the Stern layer potential, and other quantities associated with the outer Helmholtz plane, impossible. Here, we use x-ray photoelectron spectroscopy from a liquid microjet to measure the absolute surface potentials of silica nanoparticles dispersed in aqueous electrolytes. We quantitatively determine the impact of specific cations (Li+ , Na+ , K+ , and Cs+ ) in chloride electrolytes on the surface potential, the location of the shear plane, and the capacitance of the Stern layer. We find that the magnitude of the surface potential increases linearly with the hydrated-cation radius. Interpreting our data using the simplest assumptions and most straightforward understanding of Gouy-Chapman-Stern theory reveals a Stern layer whose thickness corresponds to a single layer of water molecules hydrating the silica surface, plus the radius of the hydrated cation. These results subject electrical double-layer theories to direct and falsifiable tests to reveal a physically intuitive and quantitatively verified picture of the Stern layer that is consistent across multiple electrolytes and solution conditions.

  6. Determination of retinal chromophore structure in bacteriorhodopsin with resonance Raman spectroscopy.

    Science.gov (United States)

    Smith, S O; Lugtenburg, J; Mathies, R A

    1985-01-01

    The analysis of the vibrational spectrum of the retinal chromophore in bacteriorhodopsin with isotopic derivatives provides a powerful "structural dictionary" for the translation of vibrational frequencies and intensities into structural information. Of importance for the proton-pumping mechanism is the unambiguous determination of the configuration about the C13=C14 and C=N bonds, and the protonation state of the Schiff base nitrogen. Vibrational studies have shown that in light-adapted BR568 the Schiff base nitrogen is protonated and both the C13=C14 and C=N bonds are in a trans geometry. The formation of K625 involves the photochemical isomerization about only the C13=C14 bond which displaces the Schiff base proton into a different protein environment. Subsequent Schiff base deprotonation produces the M412 intermediate. Thermal reisomerization of the C13=C14 bond and reprotonation of the Schiff base occur in the M412------O640 transition, resetting the proton-pumping mechanism. The vibrational spectra can also be used to examine the conformation about the C--C single bonds. The frequency of the C14--C15 stretching vibration in BR568, K625, L550 and O640 argues that the C14--C15 conformation in these intermediates is s-trans. Conformational distortions of the chromophore have been identified in K625 and O640 through the observation of intense hydrogen out-of-plane wagging vibrations in the Raman spectra (see Fig. 2). These two intermediates are the direct products of chromophore isomerization. Thus it appears that following isomerization in a tight protein binding pocket, the chromophore cannot easily relax to a planar geometry. The analogous observation of intense hydrogen out-of-plane modes in the primary photoproduct in vision (Eyring et al., 1982) suggests that this may be a general phenomenon in protein-bound isomerizations. Future resonance Raman studies should provide even more details on how bacterio-opsin and retinal act in concert to produce an

  7. Determination of proteins and carbohydrates in the effluents from wastewater treatment bioreactors using resonance light-scattering method.

    Science.gov (United States)

    Zhang, Meng-Lin; Sheng, Guo-Ping; Yu, Han-Qing

    2008-07-01

    A simple and sensitive method was developed for the determination of low-concentration proteins and carbohydrates in the effluents from biological wastewater treatment reactors using resonance light-scattering (RLS) technique. Two ionic dyes, Congo red and Neutral red were, respectively used as an RLS probes for the determination of proteins and carbohydrates. This method is based on the interactions between biomacromolecules and dyes, which cause a substantial increase in the resonance scattering signal of dyes in the wavelength range of 200-650 nm. The characteristics of RLS spectra of the macromolecule-dye complexes, influencing factors, and optimum analytical conditions for the measurement were explored. The method was satisfactorily applied to the measurement of proteins and carbohydrates in the effluents from 10 aerobic or anaerobic bioreactors, and a high sensitivity were achieved.

  8. Rapid Determination of Phytophthora infestans sporangia Using a Surface Plasmon Resonance Immunosensor

    DEFF Research Database (Denmark)

    Skottrup, Peter; Nicolaisen, Mogens; Justesen, Annemarie Fejer

    2007-01-01

    Phytophthora infestans is the cause of late blight disease in potato and is an economically important pathogen worldwide. Early disease detection is important to implement disease control measures. In this study a surface plasmon resonance (SPR) immunosensor for detection of P. infestans sporangia...

  9. Structure Determination of Anionic Metal Clusters via Infrared Resonance Enhanced Multiple Photon Electron Detachment Spectroscopy

    NARCIS (Netherlands)

    Haertelt, M.; Lapoutre, V. J. F.; Bakker, J. M.; Redlich, B.; Harding, D. J.; Fielicke, A.; Meijer, G.

    2011-01-01

    We report vibrational spectra of anionic metal clusters, measured via electron detachment following resonant absorption of multiple infrared photons. To facilitate the sequential absorption of the required large number of photons, the cluster beam interacts with the infrared radiation inside the

  10. Drop shape analysis for determination of dynamic contact angles by double sided elliptical fitting method

    DEFF Research Database (Denmark)

    Andersen, Nis Korsgaard; Taboryski, Rafael J.

    2017-01-01

    Contact angle measurements are a fast and simple way to measure surface properties and is therefore widely used to measure surface energy and quantify wetting of a solid surface by a liquid substance. In common praxis contact angle measurements are done with sessile drops on a horizontal surface...... fitted to a drop profile derived from the Young-Laplace equation. When measuring the wetting behaviour by tilting experiments this is not possible since it involves moving drops that are not in equilibrium. Here we present a fitting technique capable of determining the contact angle of asymmetric drops...

  11. Application of pulsed field gel electrophoresis to determine γ-ray-induced double-strand breaks in yeast chromosomal molecules

    International Nuclear Information System (INIS)

    Friedl, A.A.; Hahn, K.; Eckardt-Schupp, F.; Kellerer, A.M.; Beisker, W.

    1993-01-01

    The frequency of DNA double-strand breaks (dsb) was determined in yeast cells exposed to γ-rays under anoxic conditions. Genomic DNA of treated cells was separated by pulsed field gel electrophoresis, and two different approaches for the evaluation of the gels were employed: (1) The DNA mass distribution profile obtained by electrophoresis was compared to computed profiles, and the number of DSB per unit length was then derived in terms of a fitting procedure; (2) hybridization of selected chromosomes was performed, and a comparison of the hybridization signals in treated and untreated samples was then used to derive the frequency of dsb. The two assays gave similar results for the frequency of dsb ((1.07 ± 0.06) x 10 -9 Gy -1 bp -1 and (0.93 ± 0.09) x 10 -9 Gy -1 bp -1 , respectively). The dsb frequency was found to be linearly dependent on dose. (author)

  12. Error in the determination of the deformed shape of prismatic beams using the double integration of curvature

    Science.gov (United States)

    Sigurdardottir, Dorotea H.; Stearns, Jett; Glisic, Branko

    2017-07-01

    The deformed shape is a consequence of loading the structure and it is defined by the shape of the centroid line of the beam after deformation. The deformed shape is a universal parameter of beam-like structures. It is correlated with the curvature of the cross-section; therefore, any unusual behavior that affects the curvature is reflected through the deformed shape. Excessive deformations cause user discomfort, damage to adjacent structural members, and may ultimately lead to issues in structural safety. However, direct long-term monitoring of the deformed shape in real-life settings is challenging, and an alternative is indirect determination of the deformed shape based on curvature monitoring. The challenge of the latter is an accurate evaluation of error in the deformed shape determination, which is directly correlated with the number of sensors needed to achieve the desired accuracy. The aim of this paper is to study the deformed shape evaluated by numerical double integration of the monitored curvature distribution along the beam, and create a method to predict the associated errors and suggest the number of sensors needed to achieve the desired accuracy. The error due to the accuracy in the curvature measurement is evaluated within the scope of this work. Additionally, the error due to the numerical integration is evaluated. This error depends on the load case (i.e., the shape of the curvature diagram), the magnitude of curvature, and the density of the sensor network. The method is tested on a laboratory specimen and a real structure. In a laboratory setting, the double integration is in excellent agreement with the beam theory solution which was within the predicted error limits of the numerical integration. Consistent results are also achieved on a real structure—Streicker Bridge on Princeton University campus.

  13. Determination of an effective scoring function for RNA-RNA interactions with a physics-based double-iterative method.

    Science.gov (United States)

    Yan, Yumeng; Wen, Zeyu; Zhang, Di; Huang, Sheng-You

    2018-05-18

    RNA-RNA interactions play fundamental roles in gene and cell regulation. Therefore, accurate prediction of RNA-RNA interactions is critical to determine their complex structures and understand the molecular mechanism of the interactions. Here, we have developed a physics-based double-iterative strategy to determine the effective potentials for RNA-RNA interactions based on a training set of 97 diverse RNA-RNA complexes. The double-iterative strategy circumvented the reference state problem in knowledge-based scoring functions by updating the potentials through iteration and also overcame the decoy-dependent limitation in previous iterative methods by constructing the decoys iteratively. The derived scoring function, which is referred to as DITScoreRR, was evaluated on an RNA-RNA docking benchmark of 60 test cases and compared with three other scoring functions. It was shown that for bound docking, our scoring function DITScoreRR obtained the excellent success rates of 90% and 98.3% in binding mode predictions when the top 1 and 10 predictions were considered, compared to 63.3% and 71.7% for van der Waals interactions, 45.0% and 65.0% for ITScorePP, and 11.7% and 26.7% for ZDOCK 2.1, respectively. For unbound docking, DITScoreRR achieved the good success rates of 53.3% and 71.7% in binding mode predictions when the top 1 and 10 predictions were considered, compared to 13.3% and 28.3% for van der Waals interactions, 11.7% and 26.7% for our ITScorePP, and 3.3% and 6.7% for ZDOCK 2.1, respectively. DITScoreRR also performed significantly better in ranking decoys and obtained significantly higher score-RMSD correlations than the other three scoring functions. DITScoreRR will be of great value for the prediction and design of RNA structures and RNA-RNA complexes.

  14. Determination of chlorine, sulfur and carbon in reinforced concrete structures by double-pulse laser-induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Labutin, Timur A., E-mail: timurla@laser.chem.msu.ru [Lomonosov Moscow State University, Department of Chemistry, Leninskie Gory 1-3, Moscow 119991 (Russian Federation); Popov, Andrey M.; Zaytsev, Sergey M.; Zorov, Nikita B. [Lomonosov Moscow State University, Department of Chemistry, Leninskie Gory 1-3, Moscow 119991 (Russian Federation); Belkov, Mikhail V.; Kiris, Vasilii V.; Raikov, Sergey N. [B.I. Stepanov Institute of Physics, Nezavisimosti Ave. 68, Minsk 220072 (Belarus)

    2014-09-01

    Accurate and reliable quantitative determination of non-metal corrosion agents in concrete is still an actual task of analytical use of LIBS. Two double-pulse LIBS systems were tested as a tool for the determination of chlorine, sulfur and carbon in concretes. Both systems had collinear configuration; a laboratory setup was equipped with an ICCD and two lasers (355/532 nm + 540 nm), but a CCD was a detector for a mobile system with one laser (1064 nm). Analytical lines of Cl I at 837.59 nm, S I at 921 nm and C I at 247.86 nm were used to plot calibration curves. Optimal interpulse delays for the laboratory setup were 4 μs for chlorine and 2.8 μs for carbon, while an interpulse delay of 2 μs was optimal for chlorine and sulfur determination with the mobile system. We suggested the normalization of the Cl I line at 837.59 nm to the Mg II line at 279.08 nm (visible at 837.23 nm in the third order) to compensate for pulse-to-pulse fluctuations of chlorine lines. It provided the decrease of the detection limit of chlorine from 400 ppm to 50 ppm. Therefore, we reported that LIBS can be used to determine main corrosive active substances under ambient conditions in concrete below critical threshold values. Moreover, the application of the mobile system for in-situ qualitative assessment of corrosion way of a steel cage of a swimming pool dome was also demonstrated. It was found that chloride corrosion due to the disinfection of water was the main way for corrosion of the open part steel and the steel rebar inside the concrete. - Highlights: • Determination of chlorine, sulfur and carbon in concrete in the air. • Comparison of mobile and laboratory LIBS systems. • LOD by double-pulse LIBS under ambient conditions: for sulfur 1500 ppm, for chlorine — 50 ppm. • Background level of carbon content in concrete is about 0.27% wt.

  15. Optical-optical double resonance, laser induced fluorescence, and revision of the signs of the spin-spin constants of the boron carbide (BC) free radical

    Science.gov (United States)

    Sunahori, Fumie X.; Nagarajan, Ramya; Clouthier, Dennis J.

    2015-12-01

    The cold boron carbide free radical (BC X 4Σ-) has been produced in a pulsed discharge free jet expansion using a precursor mixture of trimethylborane in high pressure argon. High resolution laser induced fluorescence spectra have been obtained for the B 4Σ--X 4Σ- and E 4Π-X 4Σ- band systems of both 11BC and 10BC. An optical-optical double resonance (OODR) scheme was implemented to study the finer details of both band systems. This involved pumping a single rotational level of the B state with one laser and then recording the various allowed transitions from the intermediate B state to the final E state with a second laser by monitoring the subsequent E-X ultraviolet fluorescence. In this fashion, we were able to prove unambiguously that, contrary to previous studies, the spin-spin constant λ is negative in the ground state and positive in the B 4Σ- excited state. It has been shown that λ″ expected based on a semiempirical second order perturbation theory calculation of the magnitude of the spin-spin constant. The OODR spectra have also been used to validate our assignments of the complex and badly overlapped E 4Π-X 4Σ- 0-0 and 1-0 bands of 11BC. The E-X 0-0 band of 10BC was found to be severely perturbed. The ground state main electron configuration is …3σ24σ25σ11π22π0 and the derived bond lengths show that there is a 0.03 Å contraction in the B state, due to the promotion of an electron from the 4σ antibonding orbital to the 5σ bonding orbital. In contrast, the bond length elongates by 0.15 Å in the E state, a result of promoting an electron from the 5σ bonding orbital to the 2π antibonding orbitals.

  16. Development of double-pulse lasers ablation system and electron paramagnetic resonance spectroscopy for direct spectral analysis of manganese doped PVA polymer

    Science.gov (United States)

    Khalil, A. A. I.; Morsy, M. A.; El-Deen, H. Z.

    2017-11-01

    Series of manganese-co-precipitated poly (vinyl alcohol) (PVA) polymer were quantitatively and qualitatively analyzed using laser ablation system (LAS) based on double-pulse laser induced breakdown spectroscopy (DP-LIBS) and electron paramagnetic resonance (EPR) spectroscopy. The collinear nanosecond laser beams of 266 and 1064 nm were optimized to focus on the surface of the PVA polymer target. Both laser beams were employed to estimate the natural properties of the excited Mn-PVA plasma, such as electron number density (Ne), electron temperature (Te), and Mn concentration. Individual transition lines of manganese (Mn), carbon (C), lithium (Li), hydrogen (H) and oxygen (O) atoms are identified based on the NIST spectral database. The results show better responses with DP-LIBS than the single-pulse laser induced breakdown spectroscopy (SP-LIBS). On the other hand, the EPR investigation shows characteristic broad peak of Mn-nano-particles (Mn-NPs) in the range of quantum dots of superparamagnetic materials. The line width (peak-to-peak, ΔHpp) and g-value of the observed Mn-EPR peak are ∼20 mT and 2.0046, respectively. The intensities of Mn-emission line at a wavelength 403.07 nm and the Mn-EPR absorption peak were used to accurate quantify the Mn-content in the polymer matrix. The results produce linear trends within the studied concentration range with regression coefficient (R2) value of ∼0.99, and limit of detection (LOD) of 0.026 mol.% and 0.016 mol.%, respectively. The LOD values are at a fold change of about -0.2 of the studied lowest mol.%. The proposed protocols of trace element detection are of significant advantage and can be applied to the other metal analysis.

  17. Double-Bottom Chaotic Map Particle Swarm Optimization Based on Chi-Square Test to Determine Gene-Gene Interactions

    Science.gov (United States)

    Yang, Cheng-Hong; Chang, Hsueh-Wei

    2014-01-01

    Gene-gene interaction studies focus on the investigation of the association between the single nucleotide polymorphisms (SNPs) of genes for disease susceptibility. Statistical methods are widely used to search for a good model of gene-gene interaction for disease analysis, and the previously determined models have successfully explained the effects between SNPs and diseases. However, the huge numbers of potential combinations of SNP genotypes limit the use of statistical methods for analysing high-order interaction, and finding an available high-order model of gene-gene interaction remains a challenge. In this study, an improved particle swarm optimization with double-bottom chaotic maps (DBM-PSO) was applied to assist statistical methods in the analysis of associated variations to disease susceptibility. A big data set was simulated using the published genotype frequencies of 26 SNPs amongst eight genes for breast cancer. Results showed that the proposed DBM-PSO successfully determined two- to six-order models of gene-gene interaction for the risk association with breast cancer (odds ratio > 1.0; P value <0.05). Analysis results supported that the proposed DBM-PSO can identify good models and provide higher chi-square values than conventional PSO. This study indicates that DBM-PSO is a robust and precise algorithm for determination of gene-gene interaction models for breast cancer. PMID:24895547

  18. Development of surface plasmon resonance sensor for determining zinc ion using novel active nanolayers as probe.

    Science.gov (United States)

    Fen, Yap Wing; Yunus, W Mahmood Mat; Talib, Zainal Abidin; Yusof, Nor Azah

    2015-01-05

    In this study, novel active nanolayers in combination with surface plasmon resonance (SPR) system for zinc ion (Zn(2+)) detection has been developed. The gold surface used for the SPR system was modified with the novel developed active nanolayers, i.e. chitosan and chitosan-tetrabutyl thiuram disulfide (chitosan-TBTDS). Both chitosan and chitosan-TBTDS active layers were fabricated on the gold surface by spin coating technique. The system was used to monitor SPR signal for Zn(2+) in aqueous media with and without sensitivity enhancement by TBTDS. For both active nanolayers, the shift of resonance angle is directly proportional to the concentration of Zn(2+) in aqueous media. The higher shift of resonance angle was obtained for chitosan-TBTDS active nanolayer due to a specific binding of TBTDS with Zn(2+). The chitosan-TBTDS active nanolayer enhanced the sensitivity of detection down to 0.1 mg/l and also induced a selective detection towards Zn(2+). Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Three phase dynamic CT with double spiral CT: utility of determination of stomach cancer stage

    International Nuclear Information System (INIS)

    Jung, Min Ha; Kim, Hong In; Kim, Tae Hyung; Lee, Ki Yeol; Cho, June Il; Park, Cheol Min; Cha, In Ho

    1997-01-01

    To evaluate the utility of three phases of spiral CT in the diagnosis of stomach cancer. Between August 1994 and March 1995, thirty eight patients with stomach cancer, demonstrated on spiral CT, underwent surgery. Twenty-eight cases were advanced and ten were early. There were 27 men, and 11 women, and their average age was 52.8 years old (33-77). After ingestion of 600-700ml of water, 120-140ml of nonionic contrast material was injected intravenously. Spiral CT scanning was performed in 10mm slice thickness and of 10mm/sec table speed. Three phase image were obtained at 25sec (arterial phase), 60-65sec (venous phase) and 4min (equilibrium phase) after the start of bolus injection. On each phase, CT findings were compared with pathologic results, and tumor detectibility, depth of tumor invasion and lymph node metastasis was analysed. Thirty of the 38 carcinomas (79%) were detected on the arterial phase, 33 (81%) on the venous phase and 30 (79%) on the equilibrium phase. Depth of tumor invasion was measured accurately in 27 of 38 cases (71%) : T1-4/10 (40%), T2-8/11 (73%), T3-13/15 (87%), T4-2/2 (100%). We overstaged one case of T1 as T2 and two cases of T2 as T3, and understaged one case of T2 as T1 and two cases of T3 as T2. Among the 16 enlarged lymph nodes larger than 8mm, 13 cases were positive on pathologic examination and the sensitivity was 65%. With three-phase spiral CT scanning, we obtained 71% accuracy of depth of tumor invasion. The venous phase is most useful for tumor detection and for determining depth of tumor invasion and lymph node metastasis

  20. Intercomparison of Methods for Determination of Resonant Frequency Shift of a Microstrip Patch Antenna Loaded with Hevea Rubber Latex

    Directory of Open Access Journals (Sweden)

    Nor Zakiah Yahaya

    2014-01-01

    Full Text Available This paper presents an intercomparison between the finite element method, method of moment, and the variational method to determine the effect of moisture content on the resonant frequency shift of a microstrip patch loaded with wet material. The samples selected for this study were Hevea rubber latex with different percentages of moisture content from 35% to 85%. The results were compared with the measurement data in the frequency range between 1 GHz and 4 GHz. It was found that the finite element method is the most accurate among all the three computational techniques with 0.1 mean error when compared to the measured resonant frequency shift. A calibration equation was obtained to predict moisture content from the measured frequency shift with an accuracy of 2%.

  1. DEMUR: double electron muon resonance

    International Nuclear Information System (INIS)

    Vanderwater, D.A.; Brown, J.A.; Cooke, D.W.; Dodds, S.A.; Estle, T.L.; Heffner, R.H.; Leon, M.

    1980-01-01

    The details of a general theory of DEMUR are presented, with examples of current experimental interest: quartz, where the hyperfine interaction is nearly isotropic; and silicon, wherein an anisotropic species has been found. The theory will be compared with experimental data

  2. High-Resolution Nuclear Magnetic Resonance Determination of Transfer RNA Tertiary Base Pairs in Solution. 2. Species Containing a Large Variable Loop

    NARCIS (Netherlands)

    HURD, RE; ROBILLARD, GT; REID, BR

    1977-01-01

    The number of base pairs in the solution structure of several class III D3VN tRNA species from E. coli has been determined by analyzing the number of low-field (-15 to -11 ppm) proton resonances in their nuclear magnetic resonance spectra at 360 MHz. Contrary to previous reports indicating the

  3. Isovector resonances in pion charge exchange

    International Nuclear Information System (INIS)

    Bowman, J.D.

    1985-01-01

    The (π ± , π 0 ) reactions as probes of isovector resonances are discussed. Experimental observation of the isovector monopole resonance is reported. Experimental results are presented for L=0, 1, and 2 isovector resonances and are compared to random-phase approximation calculations. In the experiments 40 Ca, 60 Ni, 90 Zr, 120 Sn, 140 Ce, and 208 Pb, targets were bombarded with 165 MeV π ± beams. Neutral pions were detected and double differential cross sections were determined for angles between 0 and 33deg and for π 0 energies between 90, 180, and 230 MeV. (Auth.)

  4. Resonance rotational level crossing in the fluorosulfate radical FSO3rad and experimental determination of the rotational A and the centrifugal distortion DK constants

    Science.gov (United States)

    Kolesniková, Lucie; Koucký, Jan; Kania, Patrik; Uhlíková, Tereza; Beckers, Helmut; Urban, Štěpán

    2018-01-01

    The resonance crossing of rotational levels with different fine-structure components and different k rotational quantum numbers was observed in the rotational spectra of the symmetric top fluorosulfate radical FSO3rad. Detailed measurements were performed to analyze these weak resonances as well as the A1-A2 splittings of the K = 3 and K = 6 transitions. The resonance level crossing enabled the experimental determination of "forbidden" parameters, the rotational A and the centrifugal distortion DK constants as well as the corresponding resonance off-diagonal matrix element.

  5. Determining mode I cohesive law of Pinus pinaster by coupling double cantilever beam test with digital image correlation

    Directory of Open Access Journals (Sweden)

    J. Xavier

    2015-01-01

    Full Text Available The direct identification of the cohesive law in pure mode I of Pinus pinaster is addressed. The approach couples the double cantilever beam (DCB test with digital image correlation (DIC. Wooden beam specimens loaded in the radial-longitudinal (RL fracture propagation system are used. The strain energy release rate in mode I ( is uniquely determined from the load-displacement ( curve by means of the compliance-based beam method (CBBM. This method relies on the concept of equivalent elastic crack length ( and therefore does not require the monitoring of crack propagation during test. The crack tip opening displacement in mode I is determined from the displacement field at the initial crack tip. The cohesive law in mode I is then identified by numerical differentiation of the relationship. Moreover, the proposed procedure is validated by finite element analyses including cohesive zone modelling. It is concluded that the proposed data reduction scheme is adequate for assessing the cohesive law in pure mode I of P. pinaster

  6. Determination of chlorine, sulfur and carbon in reinforced concrete structures by double-pulse laser-induced breakdown spectroscopy

    Science.gov (United States)

    Labutin, Timur A.; Popov, Andrey M.; Zaytsev, Sergey M.; Zorov, Nikita B.; Belkov, Mikhail V.; Kiris, Vasilii V.; Raikov, Sergey N.

    2014-09-01

    Accurate and reliable quantitative determination of non-metal corrosion agents in concrete is still an actual task of analytical use of LIBS. Two double-pulse LIBS systems were tested as a tool for the determination of chlorine, sulfur and carbon in concretes. Both systems had collinear configuration; a laboratory setup was equipped with an ICCD and two lasers (355/532 nm + 540 nm), but a CCD was a detector for a mobile system with one laser (1064 nm). Analytical lines of Cl I at 837.59 nm, S I at 921 nm and C I at 247.86 nm were used to plot calibration curves. Optimal interpulse delays for the laboratory setup were 4 μs for chlorine and 2.8 μs for carbon, while an interpulse delay of 2 μs was optimal for chlorine and sulfur determination with the mobile system. We suggested the normalization of the Cl I line at 837.59 nm to the Mg II line at 279.08 nm (visible at 837.23 nm in the third order) to compensate for pulse-to-pulse fluctuations of chlorine lines. It provided the decrease of the detection limit of chlorine from 400 ppm to 50 ppm. Therefore, we reported that LIBS can be used to determine main corrosive active substances under ambient conditions in concrete below critical threshold values. Moreover, the application of the mobile system for in-situ qualitative assessment of corrosion way of a steel cage of a swimming pool dome was also demonstrated. It was found that chloride corrosion due to the disinfection of water was the main way for corrosion of the open part steel and the steel rebar inside the concrete.

  7. Study on interaction between palladium(ІІ)-Linezolid chelate with eosin by resonance Rayleigh scattering, second order of scattering and frequency doubling scattering methods using Taguchi orthogonal array design

    Science.gov (United States)

    Thakkar, Disha; Gevriya, Bhavesh; Mashru, R. C.

    2014-03-01

    Linezolid reacted with palladium to form 1:1 binary cationic chelate which further reacted with eosin dye to form 1:1 ternary ion association complex at pH 4 of Walpole's acetate buffer in the presence of methyl cellulose. As a result not only absorption spectra were changed but Resonance Rayleigh Scattering (RRS), Second-order Scattering (SOS) and Frequency Doubling Scattering (FDS) intensities were greatly enhanced. The analytical wavelengths of RRS, SOS and FDS (λex/λem) of ternary complex were located at 538 nm/538 nm, 240 nm/480 nm and 660 nm/330 nm, respectively. The linearity range for RRS, SOS and FDS methods were 0.01-0.5 μg mL-1, 0.1-2 μg mL-1 and 0.2-1.8 μg mL-1, respectively. The sensitivity order of three methods was as RRS > SOS > FDS. Accuracy of all methods were determined by recovery studies and showed recovery between 98% and 102%. Intraday and inter day precision were checked for all methods and %RSD was found to be less than 2 for all methods. The effects of foreign substances were tested on RRS method and it showed the method had good selectivity. For optimization of process parameter, Taguchi orthogonal array design L8(24) was used and ANOVA was adopted to determine the statistically significant control factors that affect the scattering intensities of methods. The reaction mechanism, composition of ternary ion association complex and reasons for scattering intensity enhancement was discussed in this work.

  8. A dual surface plasmon resonance assay for the determination of ribonuclease H activity

    Czech Academy of Sciences Publication Activity Database

    Šípová, Hana; Vaisocherová, Hana; Štepánek, J.; Homola, Jiří

    2010-01-01

    Roč. 26, č. 4 (2010), s. 1605-1611 ISSN 0956-5663 R&D Projects: GA AV ČR KAN200670701; GA MŠk OC09058; GA ČR GA202/09/0193 Grant - others:Univerzita Karlova(CZ) SVV-2010-261 304 Institutional research plan: CEZ:AV0Z20670512 Keywords : Surface plasmon resonance * Enzyme activity assay * Ribonuclease H * Biosensor Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 5.361, year: 2010

  9. Resonant ion-pair formation in the recombination of NO+ with electrons: Cross-section determination

    International Nuclear Information System (INIS)

    Le Padellec, A.; Djuric, N.; Al-Khalili, A.; Danared, H.; Derkatch, A. M.; Neau, A.; Popovic, D. B.; Rosen, S.; Semaniak, J.; Thomas, R.

    2001-01-01

    Resonant ion-pair formation from the collisions of NO + ions with electrons was studied using the heavy-ion storage ring CRYRING at the Manne Siegbahn Laboratory of Stockholm University. The total cross section is measured for the formation of N + +O - for electron energies 8--18 eV, and the results are compared with ion-pair formation in photoionization work. A peak in the cross section is observed at 12.5 eV, with a magnitude of 8.5 x 10 -19 cm 2 . An attempt to extract the cross section for the reverse process of associative ionization is made

  10. High speed resonant frequency determination applied to field mapping using perturbation techniques

    International Nuclear Information System (INIS)

    Smith, B.H.; Burton, R.J.; Hutcheon, R.M.

    1992-01-01

    Perturbation techniques are commonly used for measuring electric and magnetic field distributions in resonant structures. A field measurement system has been assembled using a Hewlett Packard model 8753C network analyzer interfaced via an HPIB bus to a personal computer to form an accurate, rapid and flexible system for data acquisition, control, and analysis of such measurements. Characterization of long linac structures (up to 3 m) is accomplished in about three minutes, minimizing thermal drift effects. This paper describes the system, its application and its extension to applications such as confirming the presence of weak, off-axis quadrupole fields in an on-axis coupled linac. (Author) 5 figs., 10 refs

  11. Determination of resonance parameters at 4.90 eV for Au 197

    International Nuclear Information System (INIS)

    Tellier, Henry; Alix, Michel

    1969-12-01

    A new study of the 4.9 eV resonance of gold was carried out by the time of flight method using the 45 MeV Saclay linac as a pulsed neutron source. Four sample thicknesses were used for the measurements. The four transmission curves were shaped analysed and the following parameters were obtained: E = 4.900 ± 0.005 eV - Γ = 137.5 ± 2.0 meV and Γ n = 15.0 ± 0.2 meV. (author) [fr

  12. In vivo determination of body composition of rats using magnetic resonance imaging.

    Science.gov (United States)

    Tang, H; Vasselli, J; Wu, E; Gallagher, D

    2000-05-01

    Magnetic resonance imaging (MRI) has potential as an instrument to measure body composition because it can discriminate various soft tissues in vivo. These soft tissues include adipose tissue, muscle, organs, and brain. We report on preliminary studies using a 4.2-tesla MRI for measuring body composition in the mouse and rat. We employed image segmentation methods that include an image correction method, a necessary requirement when the images are taken in the presence of nonuniform radio-frequency (RF) coil response. The software for 3-D data segmentation, quantification, correction, image manipulation, and visualization has been developed as a research tool. This method currently is being validated.

  13. Determination of bound and unbound water in dental alginate irreversible hydrocolloid by nuclear magnetic resonance spectroscopy.

    Science.gov (United States)

    Fellows, C M; Thomas, G A

    2009-04-01

    Alginate materials are considered unsuitable for precise fixed prosthetic rehabilitation due to their tendency to undergo spontaneous syneresis. Commercial alginate impression materials were investigated using Nuclear Magnetic Resonance (NMR) Spectroscopy to probe the relation between changes in the microscopic water environment and dimensional change to obtain a better understanding of spontaneous syneresis. NMR was used to measure the spin-lattice relaxation times (T(1)) of (1)H nuclei in water in alginate matrices to characterize changes in gel structure over time. These results were related to the dimensional stabilities of the alginate impression materials, their chemical compositions, and the Moisture Sorption Isotherms (MSI) obtained by incubation at fixed relative humidities. The rate of change of T(1) with time was found to be a better predictor of dimensional stability than MSI. The greatest dimensional stability for the alginate powders investigated was associated with a high filler:alginate ratio and a high Ca:Na ratio. Nuclear magnetic resonance spectroscopy may used to measure changes in alginate impression materials under conditions where no dimensional change can be observed directly. Changes occurred rapidly even at 100% humidity, suggesting the dimensional stability of alginate impression materials is partially independent of the rate of dehydration. The results may open a way to formulate alginate impression materials more suitable for precise fabrication of dental prostheses.

  14. Right ventricular volume and mass determined by cine magnetic resonance imaging in HIV patients with possible right ventricular dysfunction

    DEFF Research Database (Denmark)

    Kjaer, Andreas; Lebech, Anne-Mette; Gerstoft, Jan

    2006-01-01

    Impaired right ventricular (RV) function has been reported to occur in patients with HIV when studied by echocardiography. However, for accurate evaluation of RV function and morphology, first-pass radionuclide ventriculography (RNV) and cine magnetic resonance imaging (cine-MRI) are methods...... ventricular ejection fraction (RVEF). To do so, we screened patients with RNV and performed an additional cine-MRI in those with reduced RVEF determined by RNV. Ninety patients with HIV were included. To evaluate the MRI measures exactly we included 18 age- and gender-matched healthy volunteers to establish...

  15. Sensitive spectrophotometric determination of ascorbic acid in drugs and foods using surface plasmon resonance band of silver nanoparticles

    Directory of Open Access Journals (Sweden)

    Kobra Zarei

    2015-12-01

    Full Text Available A simple and sensitive procedure was proposed for spectrophotometric determination of ascorbic acid. It was found that the reduction of Ag+ to silver nanoparticles (Ag-NPs by ascorbic acid in the presence of polyvinylpyrrolidone (PVP as a stabilizing agent produce very intense surface plasmon resonance peak of Ag-NPs. The plasmon absorbance of the Ag-NPs at λ = 440 nm allows the quantitative spectrophotometric detection of the ascorbic acid. The calibration curve was linear with concentration of ascorbic acid in the range of 0.5–60 μM. The detection limit was obtained as 0.08 μM. The influence of potential interfering substances on the determination of ascorbic acid was studied. The proposed method was successfully applied for the determination of ascorbic acid in some powdered drink mixtures, commercial orange juice, natural orange juice, vitamin C injection, effervescent tablet, and multivitamin tablet.

  16. Effect of tunnel placements on clinical and magnetic resonance imaging findings 2 years after anterior cruciate ligament reconstruction using the double-bundle technique

    Directory of Open Access Journals (Sweden)

    Suomalainen P

    2014-08-01

    Full Text Available Piia Suomalainen,1 Tommi Kiekara,2 Anna-Stina Moisala,1 Antti Paakkala,2 Pekka Kannus,3 Timo Järvelä4 1Division of Orthopaedics and Traumatology, Department of Trauma, Musculoskeletal Surgery and Rehabilitation, Tampere University Hospital, Tampere, 2Medical Imaging Centre, Tampere University Hospital, Tampere, 3Injury and Osteoporosis Research Center, UKK Institute, Tampere, 4Arthroscopic and Sports Medicine Center Omasairaala, Helsinki, Finland Purpose: The purpose of the study reported here was to find out if the clinical and magnetic resonance imaging (MRI findings of a reconstructed anterior cruciate ligament (ACL have an association. Our hypothesis, which was based on the different functions of the ACL bundles, was that the visibility of the anteromedial graft would have an impact on anteroposterior stability, and the visibility of the posterolateral graft on rotational stability of the knee. Methods: This study is a level II, prospective clinical and MRI study (NCT02000258. The study involved 75 patients. One experienced orthopedic surgeon performed all double-bundle ACL reconstructions. Two independent examiners made the clinical examinations at 2-year follow-up: clinical examination of the knee; KT-1000, International Knee Documentation Committee and Lysholm knee evaluation scores; and International Knee Documentation Committee functional score. The MRI evaluations were made by two musculoskeletal radiologists separately, and the means of these measurements were used. Results: We found that the location of the graft in the tibia had an impact on the MRI visibility of the graft at 2-year follow-up. There were significantly more partially or totally invisible grafts if the insertion of the graft was more anterior in the tibia. No association was found between the clinical results and the graft locations. Conclusion: Anterior graft location in the tibia can cause graft invisibility in the MRI 2 years after ACL reconstruction, but this

  17. Optical-optical double resonance, laser induced fluorescence, and revision of the signs of the spin-spin constants of the boron carbide (BC) free radical

    Energy Technology Data Exchange (ETDEWEB)

    Sunahori, Fumie X. [Department of Chemistry and Physics, Franklin College, Franklin, Indiana 46131 (United States); Nagarajan, Ramya; Clouthier, Dennis J., E-mail: dclaser@uky.edu [Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055 (United States)

    2015-12-14

    The cold boron carbide free radical (BC X {sup 4}Σ{sup −}) has been produced in a pulsed discharge free jet expansion using a precursor mixture of trimethylborane in high pressure argon. High resolution laser induced fluorescence spectra have been obtained for the B {sup 4}Σ{sup −}–X {sup 4}Σ{sup −} and E {sup 4}Π–X {sup 4}Σ{sup −} band systems of both {sup 11}BC and {sup 10}BC. An optical-optical double resonance (OODR) scheme was implemented to study the finer details of both band systems. This involved pumping a single rotational level of the B state with one laser and then recording the various allowed transitions from the intermediate B state to the final E state with a second laser by monitoring the subsequent E–X ultraviolet fluorescence. In this fashion, we were able to prove unambiguously that, contrary to previous studies, the spin-spin constant λ is negative in the ground state and positive in the B {sup 4}Σ{sup −} excited state. It has been shown that λ″ < 0 is in fact expected based on a semiempirical second order perturbation theory calculation of the magnitude of the spin-spin constant. The OODR spectra have also been used to validate our assignments of the complex and badly overlapped E {sup 4}Π–X {sup 4}Σ{sup −} 0-0 and 1-0 bands of {sup 11}BC. The E–X 0-0 band of {sup 10}BC was found to be severely perturbed. The ground state main electron configuration is …3σ{sup 2}4σ{sup 2}5σ{sup 1}1π{sup 2}2π{sup 0} and the derived bond lengths show that there is a 0.03 Å contraction in the B state, due to the promotion of an electron from the 4σ antibonding orbital to the 5σ bonding orbital. In contrast, the bond length elongates by 0.15 Å in the E state, a result of promoting an electron from the 5σ bonding orbital to the 2π antibonding orbitals.

  18. Selective isotope determination of lanthanum by diode-laser-initiated resonance-ionization mass spectrometry

    International Nuclear Information System (INIS)

    Young, J.P.; Shaw, R.W.

    1995-01-01

    A diode-laser step has been incorporated into a resonance-ionization mass spectrometry optical excitation process to enhance the isotopic selectivity of the technique. Lanthanum isotope ratio enhancements as high as 10 3 were achieved by use of a single-frequency cw diode laser tuned to excite the first step of a three-step excitation--ionization optical process; the subsequent steps were excited by use of a pulsed dye laser. Applying the same optical technique, we measured atomic hyperfine constants for the high-lying even-parity 4 D 5/2 state of lanthanum at 30 354 cm --1 . The general utility of this spectral approach is discussed

  19. Determination of the double-polarization observable E for the reaction γp→pπ0 in the CBELSA/TAPS experiment

    International Nuclear Information System (INIS)

    Gottschall, Manuela

    2013-01-01

    In the framework of this thesis the double-polarization observable E for the reaction γp→pπ 0 was determined in the energy range of E γ =600-2400 MeV. For this in the CBELSA/TAPS experiment ar the ELSA electron-stretcher facility a circularly polarized photon beam and a longitudinally polarized butanol target were available. Additionally for the determination of the dilution factor, which specifies the contribution of reactions on the hydrogen of the butanol, data were taken on a hydrogen target and a carbon target. In order to determine the double-polarization observable E two different methods were developed. in the first method exclusively the data on the butanol target were applied and the double-polarization observable E determined by means of the dilution factor. In the second method the sum from the cross sections at antiparallel and parallel spin orientation σ 1/2 and σ 3/2 was expressed by the unpolarized cross section 2σ, which was determined by means of the data on the unpolarized hydrogen target. The results of the double-polarization observable E were compared with the predictions of the three presently most usual partial-wave analyses. While the unpolarized cross section can be well described by all three predictions, already at lowest energies differences occur between the predictions and the data, so that by the extraction of this observable new informations for the partial-wave analyses can be made available.

  20. Advances in magnetic resonance 10

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 10, presents a variety of contributions to the theory and practice of magnetic resonance. The book contains three chapters that examine superoperators in magnetic resonance; ultrasonically modulated paramagnetic resonance; and the utility of electron paramagnetic resonance (EPR) and electron-nuclear double-resonance (ENDOR) techniques for studying low-frequency modes of atomic fluctuations and their significance for understanding the mechanism of structural phase transitions in solids.

  1. Volume doubling time and growth rate of renal cell carcinoma determined by helical CT: a single-institution experience

    International Nuclear Information System (INIS)

    Lee, Ji Young; Kim, Chan Kyo; Choi, Dongil; Park, Byung Kwan

    2008-01-01

    The purpose of this study was to retrospectively evaluate the volume doubling time (VDT) and growth rate of renal cell carcinomas (RCC) on a serial computed tomography (CT) scan. Thirty pathologically proven RCCs were reviewed with helical CT. Each tumor underwent at least two CT scans. Tumor volume was determined using an area measuring tool and the summation-of-areas technique. Growth rate was evaluated in terms of diameter and volume changes. VDT and volume growth rate were compared in relation to several factors (initial diameter, initial volume, diameter growth rate, volume growth rate, tumor grade, tumor subtype, sex or age). Mean VDT of RCCs was 505 days. Mean diameter and volume growth rate were 0.59 cm/year and 19.1 cm 3 /year, respectively. For volume and diameter growth rate, tumors ≤4 cm showed lower rates than those >4 cm (P 0.05). Volume growth rate was moderately to strongly positively correlated with initial diameter, initial volume and diameter growth rate (P < 0.05). In conclusion, small RCCs grew at a slow rate both diametrically and volumetrically. More accurate assessment of tumor growth rate and VDT may be helpful to understand the natural history of RCC. (orig.)

  2. A randomized, double-blind, placebo-controlled trial to determine the effects of topical insulin on wound healing.

    Science.gov (United States)

    Rezvani, Omid; Shabbak, Elahe; Aslani, Abolfazl; Bidar, Ramin; Jafari, Mehrdad; Safarnezhad, Saeed

    2009-08-01

    Although the literature contains evidence demonstrating the beneficial effects of insulin on wound healing, no suitable method for the routine administration of insulin has been reported. A randomized, double-blind, placebo-controlled trial was conducted to determine the safety and efficacy of topical insulin on healing in 45 patients (29 men, mean age for both groups 40.62 years, range 12 to 71 years) with noninfected acute and chronic extremity wounds. Patients were randomly assigned to twice-daily topical application (spray) of 1 cc saline 0.9% for each 10 cm2 of wound with or without 10 units (0.1 cc) of insulin crystal and insulin. The endpoint was complete wound closure. Systemic glucose levels were measured before and 1 hour after treatment application. No patients developed signs or symptoms of hypoglycemia and glucose levels pre- and post-application did not differ significantly. Time to healing did not differ significantly between treatment groups. Healing rates were affected by baseline wound area, patient age, wound type (acute versus chronic), and treatment group. The mean rate of healing rate was 46.09 mm2/day in the treatment and 32.24 mm2/day in the control group (P = 0.029), independent of baseline wound size. In this study, the topical application of insulin was safe and effective. Clinical studies with a larger sample size and that include patients with diabetes mellitus are warranted.

  3. Rapid Method for the Determination of 5-Hydroxymethylfurfural and Levulinic Acid Using a Double-Wavelength UV Spectroscopy

    Directory of Open Access Journals (Sweden)

    Junhua Zhang

    2013-01-01

    Full Text Available This study reports on a rapid method for the determination of levulinic acid (LA and 5-hydroxymethylfurfural (HMF in acid hydrolyze system of glucose based on UV spectroscopy. It was found that HMF and LA have a maximum absorption at the wavelengths of 284 nm and 266 nm, respectively, in a water medium, and the absorptions of HMF and LA at 284 nm and 266 nm follow Beer’s law very well. However, it was found that a major spectral interference species will arise in the quantification of HMF and LA; nonetheless, this interference can be eliminated through the absorption treatment of charcoal. Therefore, both HMF and LA can be quantified with a double-wavelength technique. The repeatability of the method had a relative standard deviation of less than 4.47% for HMF and 2.25% for LA; the limit of quantification (LOQ was 0.017 mmol/L for HMF and 4.68 mmol/L for LA, and the recovery ranged from 88% to 116% for HMF and from 94% to 105% for LA. The present method is simple, rapid, and accurate. It is suitable to use in the research of the preparation of HMF and LA in biorefinery area.

  4. Determination of Double Bond Positions in Polyunsaturated Fatty Acids Using the Photochemical Paternò-Büchi Reaction with Acetone and Tandem Mass Spectrometry.

    Science.gov (United States)

    Murphy, Robert C; Okuno, Toshiaki; Johnson, Christopher A; Barkley, Robert M

    2017-08-15

    The positions of double bonds along the carbon chain of methylene interrupted polyunsaturated fatty acids are unique identifiers of specific fatty acids derived from biochemical reactions that occur in cells. It is possible to obtain direct structural information as to these double bond positions using tandem mass spectrometry after collisional activation of the carboxylate anions of an acetone adduct at each of the double bond positions formed by the photochemical Paternò-Büchi reaction with acetone. This reaction can be carried out by exposing a small portion of an inline fused silica capillary to UV photons from a mercury vapor lamp as the sample is infused into the electrospray ion source of a mass spectrometer. Collisional activation of [M - H] - yields a series of reverse Paternò-Büchi reaction product ions that essentially are derived from cleavage of the original carbon-carbon double bonds that yield an isopropenyl carboxylate anion corresponding to each double bond location. Aldehydic reverse Paternò-Büchi product ions are much less abundant as the carbon chain length and number of double bonds increase. The use of a mixture of D 0 /D 6 -acetone facilitates identification of these double bonds indicating product ions as shown for arachidonic acid. If oxygen is present in the solvent stream undergoing UV photoactivation, ozone cleavage ions are also observed without prior collisional activation. This reaction was used to determine the double bond positions in a 20:3 fatty acid that accumulated in phospholipids of RAW 264.7 cells cultured for 3 days.

  5. Double optomechanical transparency with direct mechanical interaction

    International Nuclear Information System (INIS)

    Li Ling-Chao; Shi Rao; Xu Jun; Hu Xiang-Ming

    2015-01-01

    We present a mechanism for double transparency in an optomechanical system. This mechanism is based on the coupling of a moving cavity mirror to a second mechanical oscillator. Due to the purely mechanical coupling and the radiation pressure, three pathways are established for excitations of the probe photons into the cavity photons. Destructive interference occurs at two different frequencies, leading to double transparency to the probe field. It is the coupling strength between the mechanical oscillators that determines the locations of the transparency windows. Moreover, the normal splitting appears for the generated Stokes field and the four-wave mixing process is inhibited on resonance. (paper)

  6. Experimental elucidation on rate-determining process of water transport in polymer electrolyte fuel cell membrane by magnetic resonance imaging

    International Nuclear Information System (INIS)

    Takita, Shinpei; Tsushima, Shohji; Hirai, Shuichiro; Kubo, Norio; Aotani, Koichiro

    2007-01-01

    We examined rate-determining process of water transport in polymer electrolyte membrane (PEM) used in fuel cells by using magnetic resonance imaging (MRI). We measured transversal water content distributions of the membrane by MRI and through-plane mass flux of water by hygrometers. Through place water flux has taken place in the membrane when relative humidify of supplied gas is not equal in both side of the membrane. MRI results revealed that diffusion coefficient of water in the membrane increases with water content of membrane, λ, whilst it shows intensive peak at λ=3-4. Diffusion resistance and mass transfer resistance involving evaporation and condensation on the interface are almost in the same order and thus water transport process in the membrane is determined by either concentration diffusion or mass transfer, depending on water content of membrane. (author)

  7. Silver nanoparticles plasmon resonance-based method for the determination of uric acid in human plasma and urine samples

    International Nuclear Information System (INIS)

    Amjadi, M.; Rahimpour, E.

    2012-01-01

    We have developed a simple and sensitive colorimetric procedure for the quantification of trace amounts of uric acid. It is based on the finding that uric acid in a medium containing ammonia and sodium hydroxide at 65 0 C can reduce silver ions to form yellow silver nanoparticles (Ag NPs). These are stabilized in solution by using poly(vinyl alcohol) as a capping agent. The yellow color of the solution that results from the localized surface plasmon resonance of Ag NPs can be observed by the bare eye. The absorbance at 415 nm is proportional to the concentration of uric acid which therefore can be determined quantitatively. The calibration curve is linear in the concentration range from 10 to 200 nM, with a limit of detection of 3.3 nM. The method was successfully applied to the determination of uric acid in human plasma and urine samples. (author)

  8. Surface Plasmon Resonance Imaging biosensor for cystatin determination based on the application of bromelain, ficin and chymopapain

    Directory of Open Access Journals (Sweden)

    Anna Sankiewicz

    2012-04-01

    Full Text Available A Surface Plasmon Resonance Imaging (SPRI sensor based on bromelain or chymopapain or ficin has been developed for specific cystatin determination. Cystatin was captured from a solution by immobilized bromelain or chymopapain or ficin due to the formation of an enzyme-inhibitor complex on the biosensor surface. The influence of bromelain, chymopapain or ficin concentration, as well as the pH of the interaction on the SPRI signal, was investigated and optimized. Sensor dynamic response range is between 0–0.6 μg/ml and the detection limit is equal to 0.1 μg/ml. In order to demonstrate the sensor potential, cystatin was determined in blood plasma, urine and saliva, showing good agreement with the data reported in the literature.

  9. Determination of aromatic fragment content in phenol-containing fractions of solid fuel conversion products using nuclear magnetic resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kanitskaya, L.V.; Kushnarev, D.F.; Polonov, V.M.; Kalabin, G.A.

    1986-03-01

    Optimum conditions are determined for obtaining quantitative nuclear magnetic resonance /sup 13/C spectra of fragments in phenol-containing fraction of coal products. Causes are analyzed of residual signals in spectra of un-protonized carbon atoms. The tests were carried out on: low-temperature carbonization tar and phenol fraction obtained during medium-temperature coking of Cherenkhovskii coal (which contains 84.13% C; 9.68% H; 1.23% S; 4.96% O); products of tar hydrogenation with various phenol content; standard phenol mixture. It was found that quantitative determination of aromatic fraction content in coal conversion products and other phenol- and amine-containing complex mixtures, using NMR spectroscopy requires the addition of dimethylsulfide or acetone in order to suppress specific interactions of phenols (amines) with relaxants and obtain quantitative subspectra of Tertiary and Quaternary aromatic carbon atoms. 16 references.

  10. Novel determination of cadmium ions using an enzyme self-assembled monolayer with surface plasmon resonance

    International Nuclear Information System (INIS)

    May May, Lee; Russell, David A.

    2003-01-01

    The activity of the enzyme urease is known to be inhibited by the heavy metal cadmium. The binding of cadmium to urease and the consequent changes of the enzyme structure are the basis of the surface plasmon resonance (SPR) biosensing system reported herein. To facilitate the formation of a self-assembled monolayer (SAM) of the urease on gold-coated glass SPR sensor disks, the enzyme has been modified with N-succinimidyl 3-(2-pyridyldithiol) propionate (SPDP). The urease monolayer was exposed to trace levels of cadmium ions and monitored by SPR. From circular dichroism (CD) data, it is believed that the conformation of the active nickel site of the urease changes upon binding of the cadmium ions. It is this change of the enzyme monolayer, measured by SPR, which has been related to the cadmium ion concentration in the range of 0-10 mg l -1 . These data are the first report of a SPR biosensor capable of detecting metal ions

  11. In vivo determination of hepatic stiffness using steady-state free precession magnetic resonance elastography.

    Science.gov (United States)

    Klatt, Dieter; Asbach, Patrick; Rump, Jens; Papazoglou, Sebastian; Somasundaram, Rajan; Modrow, Jens; Braun, Jürgen; Sack, Ingolf

    2006-12-01

    The objective of this study was to introduce an magnetic resonance elastography (MRE) protocol based on fractional motion encoding and planar wave acquisition for rapid measurements of in vivo human liver stiffness. Vibrations of a remote actuator membrane were fed by a rigid rod to the patient's surface beneath the right costal arch resulting in axial shear deflections of the liver. Data acquisition was performed using a balanced steady-state free precession (bSSFP) sequence incorporating oscillating gradients for motion sensitization. Tissue vibrations of frequency fv = 51 Hz were tuned by twice the sequence repetition time (1/fv = 2TR). Twenty axial images acquired by time-resolved through-plane wave encoding were used for planar elasticity reconstruction. The MRE data acquisition was achieved within 4 breathholds of 17 seconds each. The method was applied to 12 healthy volunteers and 2 patients with diffuse liver disease (fibrosis grade 3). MRE data acquisition was successful in all volunteers and patients. The elastic moduli were measured with values between 1.99 +/- 0.16 and 5.77 +/- 0.88 kPa. Follow-up studies demonstrated the reproducibility of the method and revealed a difference of 0.74 +/- 0.47 kPa (P analysis of the strain wave field captured by axial wave images. The measured data indicate individual variations of hepatic stiffness in healthy volunteers.

  12. Contactless, probeless and non-titrimetric determination of acid-base reactions using broadband acoustic resonance dissolution spectroscopy (BARDS).

    Science.gov (United States)

    Ahmed, M Rizwan; McSweeney, Sean; Krüse, Jacob; Vos, Bastiaan; Fitzpatrick, Dara

    2018-02-12

    pH determination is a routine measurement in scientific laboratories worldwide. Most major advances in pH measurement were made in the 19th and early 20th century. pH measurements are critical for the determination of acid base reactions. This study demonstrates how an acid-base reaction can be monitored without the use of a pH probe, indicator and titres of reagent. The stoichiometric reaction between carbonate and HCl acid yields specific quantities of CO 2 , which causes reproducible changes to the compressibility of the solvent. This in turn slows down the speed of sound in solution which is induced by a magnetic follower gently tapping the inner wall of the vessel. As a consequence the frequencies of the acoustic resonances in the vessel are reduced. This approach is called Broadband Acoustic Resonance Dissolution Spectroscopy (BARDS) which harnesses this phenomenon for many applications. The acid-carbonate experiments have also been validated using H 2 SO 4 acid and using both potassium and sodium counterions for the carbonate. This method can be used to interrogate strong acid-base reactions in a rapid and non-invasive manner using carbonate as the base. The data demonstrate the first example of a reactant also acting as an indicator. The applicability of the method to weak acids has yet to be determined. A novel conclusion from the study is that a person with a well-trained ear is capable of determining the concentration and pH of a strong acid just by listening. This brings pH measurement into the realm of human perception.

  13. Polarization dependence of double-resonance optical pumping and electromagnetically induced transparency in the 5S1/2-5P3/2-5D5/2 transition of 87Rb atoms

    International Nuclear Information System (INIS)

    Moon, Han Seb; Noh, Heung-Ryoul

    2011-01-01

    The polarization dependence of double-resonance optical pumping (DROP) in the ladder-type electromagnetically induced transparency (EIT) of the 5S 1/2 -5P 3/2 -5D 5/2 transition of 87 Rb atoms is studied. The transmittance spectra in the 5S 1/2 (F=2)-5P 3/2 (F'=3)-5D 5/2 (F''=2,3,4) transition were observed as caused by EIT, DROP, and saturation effects in the various polarization combinations between the probe and coupling lasers. The features of the double-structure transmittance spectra in the 5S 1/2 (F=2)-5P 3/2 (F'=3)-5D 5/2 (F''=4) cycling transition were attributed to the difference in saturation effect according to the transition routes between the Zeeman sublevels and the EIT according to the two-photon transition probability.

  14. The Effect of Starspots on Accurate Radius Determination of the Low-Mass Double-Lined Eclipsing Binary Gu Boo

    Science.gov (United States)

    Windmiller, G.; Orosz, J. A.; Etzel, P. B.

    2010-04-01

    GU Boo is one of only a relatively small number of well-studied double-lined eclipsing binaries that contain low-mass stars. López-Morales & Ribas present a comprehensive analysis of multi-color light and radial velocity curves for this system. The GU Boo light curves presented by López-Morales & Ribas had substantial asymmetries, which were attributed to large spots. In spite of the asymmetry, López-Morales & Ribas derived masses and radii accurate to sime2%. We obtained additional photometry of GU Boo using both a CCD and a single-channel photometer and modeled the light curves with the ELC software to determine if the large spots in the light curves give rise to systematic errors at the few percent level. We also modeled the original light curves from the work of López-Morales & Ribas using models with and without spots. We derived a radius of the primary of 0.6329 ± 0.0026 R sun, 0.6413 ± 0.0049 R sun, and 0.6373 ± 0.0029 R sun from the CCD, photoelectric, and López-Morales & Ribas data, respectively. Each of these measurements agrees with the value reported by López-Morales & Ribas (R 1 = 0.623 ± 0.016 R sun) at the level of ≈2%. In addition, the spread in these values is ≈1%-2% from the mean. For the secondary, we derive radii of 0.6074 ± 0.0035 R sun, 0.5944 ± 0.0069 R sun, and 0.5976 ± 0.0059 R sun from the three respective data sets. The López-Morales & Ribas value is R 2 = 0.620 ± 0.020 R sun, which is ≈2%-3% larger than each of the three values we found. The spread in these values is ≈2% from the mean. The systematic difference between our three determinations of the secondary radius and that of López-Morales & Ribas might be attributed to differences in the modeling process and codes used. Our own fits suggest that, for GU Boo at least, using accurate spot modeling of a single set of multi-color light curves results in radii determinations accurate at the ≈2% level.

  15. THE EFFECT OF STARSPOTS ON ACCURATE RADIUS DETERMINATION OF THE LOW-MASS DOUBLE-LINED ECLIPSING BINARY GU Boo

    International Nuclear Information System (INIS)

    Windmiller, G.; Orosz, J. A.; Etzel, P. B.

    2010-01-01

    GU Boo is one of only a relatively small number of well-studied double-lined eclipsing binaries that contain low-mass stars. Lopez-Morales and Ribas present a comprehensive analysis of multi-color light and radial velocity curves for this system. The GU Boo light curves presented by Lopez-Morales and Ribas had substantial asymmetries, which were attributed to large spots. In spite of the asymmetry, Lopez-Morales and Ribas derived masses and radii accurate to ≅2%. We obtained additional photometry of GU Boo using both a CCD and a single-channel photometer and modeled the light curves with the ELC software to determine if the large spots in the light curves give rise to systematic errors at the few percent level. We also modeled the original light curves from the work of Lopez-Morales and Ribas using models with and without spots. We derived a radius of the primary of 0.6329 ± 0.0026 R sun , 0.6413 ± 0.0049 R sun , and 0.6373 ± 0.0029 R sun from the CCD, photoelectric, and Lopez-Morales and Ribas data, respectively. Each of these measurements agrees with the value reported by Lopez-Morales and Ribas (R 1 = 0.623 ± 0.016 R sun ) at the level of ∼2%. In addition, the spread in these values is ∼1%-2% from the mean. For the secondary, we derive radii of 0.6074 ± 0.0035 R sun , 0.5944 ± 0.0069 R sun , and 0.5976 ± 0.0059 R sun from the three respective data sets. The Lopez-Morales and Ribas value is R 2 = 0.620 ± 0.020 R sun , which is ∼2%-3% larger than each of the three values we found. The spread in these values is ∼2% from the mean. The systematic difference between our three determinations of the secondary radius and that of Lopez-Morales and Ribas might be attributed to differences in the modeling process and codes used. Our own fits suggest that, for GU Boo at least, using accurate spot modeling of a single set of multi-color light curves results in radii determinations accurate at the ∼2% level.

  16. Multisoliton solutions in terms of double Wronskian determinant for a generalized variable-coefficient nonlinear Schroedinger equation from plasma physics, arterial mechanics, fluid dynamics and optical communications

    International Nuclear Information System (INIS)

    Lue Xing; Zhu Hongwu; Yao Zhenzhi; Meng Xianghua; Zhang Cheng; Zhang Chunyi; Tian Bo

    2008-01-01

    In this paper, the multisoliton solutions in terms of double Wronskian determinant are presented for a generalized variable-coefficient nonlinear Schroedinger equation, which appears in space and laboratory plasmas, arterial mechanics, fluid dynamics, optical communications and so on. By means of the particularly nice properties of Wronskian determinant, the solutions are testified through direct substitution into the bilinear equations. Furthermore, it can be proved that the bilinear Baecklund transformation transforms between (N - 1)- and N-soliton solutions

  17. Studies on local preparation of double antibody radioimmunoassay for determination of alpha fetoprotein as a tumor marker

    International Nuclear Information System (INIS)

    Elkolaly, M.T.; Mehany, N.L.; Ragab, M.T.; El-Mohty, A.A.

    2001-01-01

    The preparation of primary reagents of AFP- RIA technique with low cost is considered to be one of the main objective of labelled compounds Dept., Radioisotope production Division, Hot Labs Centre, Atomic Energy Authority, Egypt. The development of a radioimmunoassay system based on local production of basic reagents for the measurement of AFP in human serum is described. The assay followed by 100 μ1 of locally prepared 125 I-AFP to 100 μ1 standards and unknown samples. After overnight incubation at 4 degree, separating reagents were added in following sequence 100 μ1 non-immune rabbit serum (1:200) followed by addition of 100μ1 of donkey anti-rabbit serum, (1:20), then 500μ1 of 8 percentage polyethylene glycol (PEG) were added into all assay tubes. The tubes were allowed to stand for 30 minutes at room temperature and then centrifuged for 15 minutes. the tubes were decanted and counted in a gamma counter. The results of the present study showed that the assay is highly sensitive where the detection limit or minimal detectable dose of AFP assay approximately 1.5 I U/ml. The reliability of the present procedure was assessed by examining its reproducibility on pooled human serum samples selected to represent different levels of AFP. The data of intra-assay and intra-assay precision revealed the consistency of the results obtained by the method of the present study. The present technique for determination of serum AFP agreed well with commercially available kits (DPC, double antibody-diagnostic product corporation, los angeles, USA). The technical simplicity of this specific, accurate and reasonably precise method may suggest that the technique should be suited for routine laboratory use

  18. Molecularly imprinted sensor based on Russian Matryoshka structured molecules for enhanced specific identification and double amplification in ultra-trace Tb3+ determination.

    Science.gov (United States)

    Li, Jianping; Yang, Bin; Pan, Hongcheng; Xu, Guobao

    2018-06-30

    The selective and sensitive detection of rare earth elements is thought to be difficult because the concentration of those elements in the sample is commonly at a low level and they normally have severe mutual interference which is caused by homologous chemical properties. In this study, a novel molecularly imprinted polymer (MIP) sensor was fabricated for highly sensitive and selective determination of ultra-trace Tb 3+ . The Tb 3+ -ethylenediaminetetraacetic acid complex (Tb-EDTA) as the template molecule was incorporated into mono-6-mercapto-β-cyclodextrin (mono-6-SH-β-CD) to form a Russian Matryoshka (RM)-structured molecule (CD/Tb-EDTA). Titanium isopropoxide was utilized in vapor sol-gel polymerization to construct MIP membrane. Moreover, the selectivity of the RM MIP sensor was remarkably enhanced by the "triple-selectivity" recognition of EDTA-to-Tb 3+ , β-CD-to-(Tb-EDTA), and 3D cavity-to-(CD/Tb-EDTA), while the sensitivity of the MIP sensor was significantly improved by ECL signal enhancement based on double amplification, in other words, the electrochemiluminescence resonance energy transfer (ECL-RET) between the ECL donor of CD/Tb-EDTA and the ECL acceptor of Ru(bpy) 3 2+ , and the ECL enhancement by the co-reactant of CD/Tb-EDTA on Ru(bpy) 3 Cl 2 . When the imprinted cavities were occupied by Tb-EDTA during rebinding, the host-guest inclusion structured complex was formed and the ECL intensities produced by the Ru(bpy) 3 Cl 2 ECL system increased with increasing concentration of Tb-EDTA. The proposed sensor was used for quantitative analysis of Tb 3+ with concentrations ranging from 8.00 × 10 -13 mol/L to 4.00 × 10 -9 mol/L and successfully applied to detect Tb 3+ in seawater samples. The detection limit of the sensor was found to be 3.90 × 10 -13 mol/L (DL = 3δ b /K), which is lower than previously reported values. Thus, the fabricated sensor is feasible for practical applications. Copyright © 2018 Elsevier B.V. All rights

  19. Different approaches to synovial membrane volume determination by magnetic resonance imaging: manual versus automated segmentation

    DEFF Research Database (Denmark)

    Østergaard, Mikkel

    1997-01-01

    Automated fast (5-20 min) synovial membrane volume determination by MRI, based on pre-set post-gadolinium-DTPA enhancement thresholds, was evaluated as a substitute for a time-consuming (45-120 min), previously validated, manual segmentation method. Twenty-nine knees [rheumatoid arthritis (RA) 13...

  20. Determination of hemispheric language dominance in the surgical epilepsy patient: diagnostic properties of functional magnetic resonance imaging.

    Science.gov (United States)

    Spritzer, Scott D; Hoerth, Matthew T; Zimmerman, Richard S; Shmookler, Aaron; Hoffman-Snyder, Charlene R; Wellik, Kay E; Demaerschalk, Bart M; Wingerchuk, Dean M

    2012-09-01

    Presurgical evaluation for refractory epilepsy typically includes assessment of cognitive and language functions. The reference standard for determination of hemispheric language dominance has been the intracarotid amobarbital test (IAT) but functional magnetic resonance imaging (fMRI) is increasingly used. To critically assess current evidence regarding the diagnostic properties of fMRI in comparison with the IAT for determination of hemispheric language dominance. The objective was addressed through the development of a structured critically appraised topic. This included a clinical scenario, structured question, literature search strategy, critical appraisal, results, evidence summary, commentary, and bottom-line conclusions. Participants included consultant and resident neurologists, a medical librarian, clinical epidemiologists, and content experts in the fields of epilepsy and neurosurgery. A systematic review and meta-analysis that compared the sensitivity and specificity of fMRI to IAT-determined language lateralization was selected for critical appraisal. The review included data from 23 articles (n=442); study methodology varied widely. fMRI was 83.5% sensitive and 88.1% specific for detection of hemispheric language dominance. There are insufficient data to support routine use of fMRI for the purpose of determining hemispheric language dominance in patients with intractable epilepsy. Larger, well-designed studies of fMRI for language and other cognitive outcomes as part of the presurgical and postsurgical evaluation of epilepsy patients are necessary.

  1. Validated ¹H and 13C Nuclear Magnetic Resonance Methods for the Quantitative Determination of Glycerol in Drug Injections.

    Science.gov (United States)

    Lu, Jiaxi; Wang, Pengli; Wang, Qiuying; Wang, Yanan; Jiang, Miaomiao

    2018-05-15

    In the current study, we employed high-resolution proton and carbon nuclear magnetic resonance spectroscopy (¹H and 13 C NMR) for quantitative analysis of glycerol in drug injections without any complex pre-treatment or derivatization on samples. The established methods were validated with good specificity, linearity, accuracy, precision, stability, and repeatability. Our results revealed that the contents of glycerol were convenient to calculate directly via the integration ratios of peak areas with an internal standard in ¹H NMR spectra, while the integration of peak heights were proper for 13 C NMR in combination with an external calibration of glycerol. The developed methods were both successfully applied in drug injections. Quantitative NMR methods showed an extensive prospect for glycerol determination in various liquid samples.

  2. Double isotopic method using dansyl chloride for the determination of GABA in rat C6 astrocytoma cell cultures

    Energy Technology Data Exchange (ETDEWEB)

    Kohl, R.L.; Quay, W.B.; Perez-Polo, J.R.

    1986-01-01

    Methods are described for the quantitative measurement of GABA in culture. The method can be adapted to any amino acid or dansyl-chloride-reactive species. The sensitivity and selectivity of the procedure result from the double isotopic design in which (/sup 14/C)-labeled internal standard was added to the samples before reaction with (3M)-labeled dansyl chloride. Values obtained by ion-exchange amino acid analysis of cultures agree closely with the values obtained by the double isotopic method. This method is sensitive enough to measure GABA intracellularly and the condition medium.

  3. On experimental determination of characteristics of nuclear fusion reactions from mu-molecular resonance states

    International Nuclear Information System (INIS)

    Bystritskij, V.M.; Pen'kov, F.M.

    1997-01-01

    Charge-nonsymmetrical deuterium-helium muon complexes (dμHe) are studied. A method is proposed for experimentally determining the rates of nuclear fusion reactions in dμHe molecules in the J=1 and J=0 states (J is the orbital moment of the system) and the partial rates for radiative decay of these complexes in these states. Experiments are supposed to be carried out at meson factories with gaseous and cryogenic targets filled with a mixture of deuterium and helium

  4. Intersubunit distances in full-length, dimeric, bacterial phytochrome Agp1, as measured by pulsed electron-electron double resonance (PELDOR) between different spin label positions, remain unchanged upon photoconversion.

    Science.gov (United States)

    Kacprzak, Sylwia; Njimona, Ibrahim; Renz, Anja; Feng, Juan; Reijerse, Edward; Lubitz, Wolfgang; Krauss, Norbert; Scheerer, Patrick; Nagano, Soshichiro; Lamparter, Tilman; Weber, Stefan

    2017-05-05

    Bacterial phytochromes are dimeric light-regulated histidine kinases that convert red light into signaling events. Light absorption by the N-terminal photosensory core module (PCM) causes the proteins to switch between two spectrally distinct forms, Pr and Pfr, thus resulting in a conformational change that modulates the C-terminal histidine kinase region. To provide further insights into structural details of photoactivation, we investigated the full-length Agp1 bacteriophytochrome from the soil bacterium Agrobacterium fabrum using a combined spectroscopic and modeling approach. We generated seven mutants suitable for spin labeling to enable application of pulsed EPR techniques. The distances between attached spin labels were measured using pulsed electron-electron double resonance spectroscopy to probe the arrangement of the subunits within the dimer. We found very good agreement of experimental and calculated distances for the histidine-kinase region when both subunits are in a parallel orientation. However, experimental distance distributions surprisingly showed only limited agreement with either parallel- or antiparallel-arranged dimer structures when spin labels were placed into the PCM region. This observation indicates that the arrangements of the PCM subunits in the full-length protein dimer in solution differ significantly from that in the PCM crystals. The pulsed electron-electron double resonance data presented here revealed either no or only minor changes of distance distributions upon Pr-to-Pfr photoconversion. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  5. Double-phase {sup 18}F-FDG PET-CT for determination of pulmonary tuberculoma activity

    Energy Technology Data Exchange (ETDEWEB)

    Kim, In-Ju; Kim, Seong-Jang; Kim, Yong-Ki [Pusan National University Hospital, Department of Nuclear Medicine, Busan (Korea); Pusan National University Hospital, Medical Research Institute, Busan (Korea); Lee, Jung Sub [Pusan National University Hospital, Medical Research Institute, Busan (Korea); Pusan National University Hospital, Department of Orthopaedic Surgery, Busan (Korea); Jeong, Yeon Joo [Pusan National University Hospital, Medical Research Institute, Busan (Korea); Pusan National University Hospital, Department of Radiology, Busan (Korea); Jun, Sungmin; Nam, Hyun Yul [Pusan National University Hospital, Department of Nuclear Medicine, Busan (Korea); Kim, Ju Sung [College of Medical and Life Sciences, Silla University, Department of Nursing, Busan (Korea)

    2008-04-15

    The aim of this study is to evaluate the potential role of double phase acquisition of {sup 18}F fluorodeoxyglucose (FDG) positron emission tomography (PET) for the differentiation of active pulmonary tuberculoma. A total of 25 consecutive patients with pulmonary tuberculoma were enrolled. PET/CT imaging was performed 60 (range 53-71) and 120 min (range 109-131) after injection of {sup 18}F-FDG. The intensity of {sup 18}F-FDG uptake by pulmonary lesions was assessed visually, and the intensity was scored with a four-point scale (grade 1: absent, grade 2: faint, grade 3: moderate, grade 4: intense). Active tuberculoma shows statistically significant higher values in maximal standardized uptake values SUV{sub maxE} (active = 2.3 {+-} 0.75, inactive = 0.79 {+-} 0.15), SUV{sub maxD} (active = 2.48 {+-} 0.79, inactive = 0.75 {+-} 0.13), and %{delta}SUV{sub max} (active = 8.07 {+-} 7.77%, inactive = -3.83 {+-} 6.59) than those of inactive tuberculoma. When greater than or equal to visual grade 2 was used as the cutoff value, the sensitivity and specificity were 100 and 81.8%. When SUV{sub maxE} 1.05 was used as the cutoff point, the sensitivity and specificity were 100 and 100%. When SUV{sub maxD} 0.97 was used as the cutoff value, the sensitivity and specificity were 92.8 and 100%. When %{delta}SUV{sub max} 6.59 was used as the cutoff value, the sensitivity and specificity were 71.4 and 100%. The %{delta}SUV{sub max} was the potent predictor by logistic regression analysis. The {delta}SUV{sub max} is a potential predictor for activity of pulmonary tuberculoma. However, the diagnostic performances were similar between visual and quantitative analyses. The visual assessment may be sufficient for determination of pulmonary tuberculoma activity. Further studies are needed to confirm these results and improve statistical accuracy. (orig.)

  6. Precise determination of Pb isotope ratios by simple double spike MC-ICP-MS technique without Tl addition

    Digital Repository Service at National Institute of Oceanography (India)

    Makishima, A.; Nath, B.N.; Nakamura, E.

    A double-spike multicollector ICP-MS (DS-MC-ICP-MS) technique for Pb isotope analysis without Tl addition is established and its analytical performance is examined in detail. This simple DS-MC-ICP-MS technique using 20 ng ml sup(-1) gave averages...

  7. Solution structure of apamin determined by nuclear magnetic resonance and distance geometry

    Energy Technology Data Exchange (ETDEWEB)

    Pease, J.H.B.; Wemmer, D.E.

    1988-11-01

    The solution structure of the bee venom neurotoxin apamin has been determined with a distance geometry program using distance constraints derived from NMR. Twenty embedded structures were generated and refined by using the program DSPACE. After error minimization using both conjugate gradient and dynamics algorithms, six structures had very low residual error. Comparisons of these show that the backbone of the peptide is quite well-defined with the largest rms difference between backbone atoms in these structures of 1.34 /Angstrom/. The side chains have far fewer constraints and show greater variability in their positions. The structure derived here is generally consistent with the qualitative model previously described, with most differences occurring in the loop between the ..beta..-turn (residues 2-5) and the C-terminal ..cap alpha..-helix (residues 9-17). Comparisons are made with previously derived models from NMR data and other methods.

  8. Solution structure of apamin determined by nuclear magnetic resonance and distance geometry

    International Nuclear Information System (INIS)

    Pease, J.H.B.; Wemmer, D.E.

    1988-01-01

    The solution structure of the bee venom neurotoxin apamin has been determined with a distance geometry program using distance constraints derived from NMR. Twenty embedded structures were generated and refined by using the program DSPACE. After error minimization using both conjugate gradient and dynamics algorithms, six structures had very low residual error. Comparisons of these show that the backbone of the peptide is quite well-defined with the largest rms difference between backbone atoms in these structures of 1.34 /Angstrom/. The side chains have far fewer constraints and show greater variability in their positions. The structure derived here is generally consistent with the qualitative model previously described, with most differences occurring in the loop between the β-turn (residues 2-5) and the C-terminal α-helix (residues 9-17). Comparisons are made with previously derived models from NMR data and other methods

  9. The double isotope technique for in vivo determination of the tissue-to-blood partition coefficient for xenon in human subcutaneous adipose tissue--an evaluation

    DEFF Research Database (Denmark)

    Jelnes, Rolf; Astrup, A; Bülow, J

    1985-01-01

    the partition coefficient found by the double isotope technique, significantly lower values are obtained than if the in vitro determined coefficient is used. This difference is explained mainly by local dilution when injecting xenon subcutaneously. In short-term studies, utilization of the double isotope...... technique reduces the coefficient of variation on average flow determinations, thus an improvement in accuracy of local blood flow estimation can be obtained compared to the method in which an average partition coefficient is used. For long-term studies a partition coefficient of 7.5 ml g-1 seems valid.......Local subcutaneous 133xenon (133Xe) elimination was registered in the human forefoot in 34 patients. The tissue/blood partition coefficient for Xe was estimated individually by simultaneous registration of 133Xe and [131I]antipyrine ([131I]AP) washout from the same local depot. When measured...

  10. Magnetic resonance imaging of the lumbar spine: determining clinical impact and potential harm from overuse.

    Science.gov (United States)

    Wnuk, Nathan M; Alkasab, Tarik K; Rosenthal, Daniel I

    2018-04-18

    Lumbar spine MRI is frequently said to be "overused" in the evaluation of low-back pain, yet data concerning the extent of overuse and on potential harmful effects are lacking. To determine the proportion of examinations with a detectable impact on patient care (actionable outcomes). Retrospective cohort study PATIENT SAMPLE: 5,365 outpatient lumbar spine MR examinations OUTCOME MEASURES: Actionable outcomes included: 1) findings leading to an intervention making use of anatomical information such as surgery; 2) new diagnoses of cancer, infection, or fracture; or 3) following known lumbar spine pathology. Potential harm was assessed by identifying examinations where suspicion of cancer or infection was raised but no positive diagnosis made. A medical record aggregation/search system was used to identify lumbar spine MR examinations with positive outcome measures. Patient notes were examined to verify outcomes. A random sample was manually inspected to identify missed positive outcomes. The proportion of actionable lumbar spine MRIs was 13%, although 93% were appropriate according to American College of Radiology guidelines. Of 36 suspected cases of cancer/infection 81% were false positives. Further investigations were ordered on 59% of suspicious exams, 86% of which were false positives. The proportion of lumbar spine MR examinations that inform management is small. The false positive rate and proportion of false positives involving further investigation is high. Further study to improve the efficiency of imaging is warranted. Copyright © 2018 Elsevier Inc. All rights reserved.

  11. Electron spin resonance as a high sensitivity technique for environmental magnetism: determination of contamination in carbonate sediments

    Science.gov (United States)

    Crook, Nigel P.; Hoon, Stephen R.; Taylor, Kevin G.; Perry, Chris T.

    2002-05-01

    This study investigates the application of high sensitivity electron spin resonance (ESR) to environmental magnetism in conjunction with the more conventional techniques of magnetic susceptibility, vibrating sample magnetometry (VSM) and chemical compositional analysis. Using these techniques we have studied carbonate sediment samples from Discovery Bay, Jamaica, which has been impacted to varying degrees by a bauxite loading facility. The carbonate sediment samples contain magnetic minerals ranging from moderate to low concentrations. The ESR spectra for all sites essentially contain three components. First, a six-line spectra centred around g = 2 resulting from Mn2+ ions within a carbonate matrix; second a g = 4.3 signal from isolated Fe3+ ions incorporated as impurities within minerals such as gibbsite, kaolinite or quartz; third a ferrimagnetic resonance with a maxima at 230 mT resulting from the ferrimagnetic minerals present within the bauxite contamination. Depending upon the location of the sites within the embayment these signals vary in their relative amplitude in a systematic manner related to the degree of bauxite input. Analysis of the ESR spectral components reveals linear relationships between the amplitude of the Mn2+ and ferrimagnetic signals and total Mn and Fe concentrations. To assist in determining the origin of the ESR signals coral and bauxite reference samples were employed. Coral representative of the matrix of the sediment was taken remote from the bauxite loading facility whilst pure bauxite was collected from nearby mining facilities. We find ESR to be a very sensitive technique particularly appropriate to magnetic analysis of ferri- and para-magnetic components within environmental samples otherwise dominated by diamagnetic (carbonate) minerals. When employing typical sample masses of 200 mg the practical detection limit of ESR to ferri- and para-magnetic minerals within a diamagnetic carbonate matrix is of the order of 1 ppm and 1 ppb

  12. Nuclear magnetic resonance line-shape analysis and determination of exchange rates

    International Nuclear Information System (INIS)

    Rao, B.D.

    1989-01-01

    The fact that chemical exchange processes occur at rates that cover a broad range and produce readily detectable effects on the spectrum is one of the attractive features of high-resolution NMR. The description of these line shapes in the presence of spin-spin coupling requires the density matrix theory which is rather complex. Analysis of the line shapes usually needs computer simulations and is capable of providing reliable information on the exchange rates as well as spectral parameters in the absence of exchange. Simplified procedures, ignoring spin-spin coupling, often result in deviations in these exchange and spectral parameters determined. A step-by-step procedure is detailed in this chapter for setting up the matrices required for computing the line shapes of exchanges involving weakly coupled spin systems on the basis of the density matrix theory without the need for a detailed understanding of the theory. A knowledge of the energy level structure and allowed transitions in the NMR spectra of the individual weakly coupled spin systems is all that is required. The procedure is amenable to numerical computation. The group of illustrative examples chosen to demonstrate the development of the computational tools cover some of the commonly encountered cases of exchange from simple systems to rather complex ones. Such exchanges occur frequently in biological molecules, especially those involving enzyme-substrate complexes. In cases where the experimental line shapes are obtained with respectable precision, and the relevant exchange processes are unambiguously identifiable, the computer simulation method of line-shape analysis is capable of providing useful and incisive information. The example of the 31P exchanges in the adenylate kinase is illustrative of this point

  13. Determination of avermectins by the internal standard recovery correction - high performance liquid chromatography - quantitative Nuclear Magnetic Resonance method.

    Science.gov (United States)

    Zhang, Wei; Huang, Ting; Li, Hongmei; Dai, Xinhua; Quan, Can; He, Yajuan

    2017-09-01

    Quantitative Nuclear Magnetic Resonance (qNMR) is widely used to determine the purity of organic compounds. For the compounds with lower purity especially molecular weight more than 500, qNMR is at risk of error for the purity, because the impurity peaks are likely to be incompletely separated from the peak of major component. In this study, an offline ISRC-HPLC-qNMR (internal standard recovery correction - high performance liquid chromatography - qNMR) was developed to overcome this problem. It is accurate by excluding the influence of impurity; it is low-cost by using common mobile phase; and it extends the applicable scope of qNMR. In this method, a mix solution of the sample and an internal standard was separated by HPLC with common mobile phases, and only the eluents of the analyte and the internal standard were collected in the same tube. After evaporation and re-dissolution, it was determined by qNMR. A recovery correction factor was determined by comparison of the solutions before and after these procedures. After correction, the mass fraction of analyte was constant and it was accurate and precise, even though the sample loss varied during these procedures, or even in bad resolution of HPLC. Avermectin B 1 a with the purity of ~93% and the molecular weight of 873 was analyzed. Moreover, the homologues of avermectin B 1 a were determined based on the identification and quantitative analysis by tandem mass spectrometry and HPLC, and the results were consistent with the results of traditional mass balance method. The result showed that the method could be widely used for the organic compounds, and could further promote qNMR to become a primary method in the international metrological systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Using Monoclonal Antibody to Determine Lead Ions with a Localized Surface Plasmon Resonance Fiber-optic Biosensor

    Directory of Open Access Journals (Sweden)

    Mon-Fu Chung

    2008-01-01

    Full Text Available A novel reflection-based localized surface plasmon resonance (LSPR fiber-optic probe has been developed to determine the heavy metal lead ion concentration. Monoclonal antibody as the detecting probe containing massive amino groups to capture Pb(II-chelate complexes was immobilized onto gold nanoparticle-modified optical fiber (NMAuOF. The optimal immobilizing conditions of monoclonal antibody on to the NMAuOF are 189 μg/mL in pH7.4 PBS for 2 h at 25°C. The absorbability of the functionalized NMAuOF sensor increases to 12.2 % upon changing the Pb(II-EDTA level from 10 to 100 ppb with a detection limit of 0.27 ppb. The sensor retains 92.7 % of its original activity and gives reproducible results after storage in 5% D-( -Trehalose dehydrate solution at 4°C for 35 days. In conclusion, the monoclonal antibody-functionalized NMAuOF sensor shows a promising result for determining the concentration of Pb(II with high sensitivity.

  15. Indirect spectrophotometric determination of sulfadiazine based on localized surface plasmon resonance peak of silver nanoparticles after cloud point extraction.

    Science.gov (United States)

    Kazemi, Elahe; Dadfarnia, Shayessteh; Haji Shabani, Ali Mohammad; Fattahi, Mohammad Reza; Khodaveisi, Javad

    2017-12-05

    A novel, efficient, easy to use, environmentally friendly and cost-effective methodology is developed for the indirect spectrophotometric determination of sulfadiazine in different samples. The method is based on the micelle-mediated extraction of silver sulfadiazine and converting the silver content of the resultant surfactant-rich phase to the silver nanoparticles via generation of [Ag(NH 3 ) 2 ] + followed by its chemical reduction using ascorbic acid. The changes in the amplitude of localized surface plasmon resonance peak of silver nanoparticles as a function of sulfadiazine concentration in the sample solution was monitored using fiber optic linear array spectrophotometry at 457nm. The experimental conditions were thoroughly investigated and optimized. Under the optimized condition, the developed procedure showed dynamic linear calibration within the range of 10.0-800.0μgL -1 with a detection limit of 2.8μgL -1 for sulfadiazine. The relative standard deviation of the method for six replicate measurements at 150.0μgL -1 of sulfadiazine was 4.7%. The developed method was successfully applied to the determination of sulfadiazine in different samples including well water, human urine, milk and pharmaceutical formulation. Copyright © 2017. Published by Elsevier B.V.

  16. Indirect spectrophotometric determination of sulfadiazine based on localized surface plasmon resonance peak of silver nanoparticles after cloud point extraction

    Science.gov (United States)

    Kazemi, Elahe; Dadfarnia, Shayessteh; Haji Shabani, Ali Mohammad; Fattahi, Mohammad Reza; Khodaveisi, Javad

    2017-12-01

    A novel, efficient, easy to use, environmentally friendly and cost-effective methodology is developed for the indirect spectrophotometric determination of sulfadiazine in different samples. The method is based on the micelle-mediated extraction of silver sulfadiazine and converting the silver content of the resultant surfactant-rich phase to the silver nanoparticles via generation of [Ag(NH3)2]+ followed by its chemical reduction using ascorbic acid. The changes in the amplitude of localized surface plasmon resonance peak of silver nanoparticles as a function of sulfadiazine concentration in the sample solution was monitored using fiber optic linear array spectrophotometry at 457 nm. The experimental conditions were thoroughly investigated and optimized. Under the optimized condition, the developed procedure showed dynamic linear calibration within the range of 10.0-800.0 μg L- 1 with a detection limit of 2.8 μg L- 1 for sulfadiazine. The relative standard deviation of the method for six replicate measurements at 150.0 μg L- 1 of sulfadiazine was 4.7%. The developed method was successfully applied to the determination of sulfadiazine in different samples including well water, human urine, milk and pharmaceutical formulation.

  17. Localized surface plasmon resonance of gold nanoparticles as colorimetric probes for determination of Isoniazid in pharmacological formulation

    Science.gov (United States)

    Zargar, Behrooz; Hatamie, Amir

    2013-04-01

    Isoniazid is an important antibiotic, which is widely used to treat tuberculosis. This study presents a colorimetric method for the determination of Isoniazid based on localized surface plasmon resonance (LSPR) property of gold nanoparticles. An LSPR band is produced by reducing gold ions in solution using Isoniazid as the reducing agent. Influences of the following relevant variables were examined and optimized in the experiment, formation time of gold nanoparticles, pH, buffer and stabilizer. These tests demonstrated that under optimum conditions the absorbance of Au nanoparticles at 530 nm related linearly to the concentration of Isoniazid in the range of 1.0-8.0 μg mL-1 with a detection limit of 0.98 μg mL-1. This colorimetric method has been successfully applied to the determine Isoniazid in tablets and spiked serum samples. The proposed colorimetric assay exhibits good reproducibility and accuracy, providing a simple and rapid method for analysis of Isoniazid.

  18. Determination of the Antioxidant Status of the Skin by In Vivo-Electron Paramagnetic Resonance (EPR Spectroscopy

    Directory of Open Access Journals (Sweden)

    Silke Barbara Lohan

    2015-08-01

    Full Text Available Organisms produce free radicals which are essential for various metabolic processes (enzymatic oxidation, cellular respiration, signaling. Antioxidants are important chemical compounds that specifically prevent the oxidation of substances by scavenging radicals, especially reactive oxygen species (ROS. Made up of one or two unpaired electrons, ROS are free radicals that are highly reactive and can attack other metabolites. By using electron paramagnetic resonance (EPR spectroscopy, it is possible to measure paramagnetic substances such as free radicals. Therefore the dermal antioxidant activity can be determined by applying semi-stable radicals onto the skin and measuring the antioxidant-induced radical scavenging activity in the skin. In recent years, EPR has been developed as a spectroscopic method for determining the antioxidant status in vivo. Several studies have shown that an additional uptake of dietary supplements, such as carotenoids or vitamin C in physiological concentrations, provide a protective effect against free radicals. Using the EPR technique it could be demonstrated that the radical production in stress situations, such as irradiation with infrared and visible light, was reduced with time. However, not only the oral uptake of antioxidants, but also the topical application of antioxidants, e.g., a hyperforin-rich cream, is very useful against the development of oxidative stress. Regular application of a hyperforin-rich cream reduced radical formation. The skin lipids, which are very important for the barrier function of the skin, were also stabilized.

  19. Influence of slice thickness on the determination of left ventricular wall thickness and dimension by magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ohnishi, Shusaku; Fukui, Sugao; Atsumi, Chisato and others

    1989-02-01

    Wall thickness of the ventricular septum and left ventricle, and left ventricular cavity dimension were determined on magnetic resonance (MR) images with slices 5 mm and 10 mm in thickness. Subjects were 3 healthy volunteers and 7 patients with hypertension (4), hypertrophic cardiomyopathy (one) or valvular heart disease (2). In visualizing the cardiac structures such as left ventricular papillary muscle and right and left ventricles, 5 mm-thick images were better than 10 mm-thick images. Edges of ventricular septum and left ventricular wall were more clearly visualized on 5 mm-thick images than 10 mm-thick images. Two mm-thick MR images obtained from 2 patients yielded the most excellent visualization in end-systole, but failed to reveal cardiac structures in detail in end-diastole. Phantom studies revealed no significant differences in image quality of 10 mm and 5 mm in thickness in the axial view 80 degree to the long axis. In the axial view 45 degree to the long axis, 10 mm-thick images were inferior to 5 mm-thick images in detecting the edge of the septum and the left ventricular wall. These results indicate that the selection of slice thickness is one of the most important determinant factors in the measurement of left ventricular wall thickness and cavity dimension. (Namekawa, K).

  20. Influence of slice thickness on the determination of left ventricular wall thickness and dimension by magnetic resonance imaging

    International Nuclear Information System (INIS)

    Ohnishi, Shusaku; Fukui, Sugao; Atsumi, Chisato

    1989-01-01

    Wall thickness of the ventricular septum and left ventricle, and left ventricular cavity dimension were determined on magnetic resonance (MR) images with slices 5 mm and 10 mm in thickness. Subjects were 3 healthy volunteers and 7 patients with hypertension (4), hypertrophic cardiomyopathy (one) or valvular heart disease (2). In visualizing the cardiac structures such as left ventricular papillary muscle and right and left ventricles, 5 mm-thick images were better than 10 mm-thick images. Edges of ventricular septum and left ventricular wall were more clearly visualized on 5 mm-thick images than 10 mm-thick images. Two mm-thick MR images obtained from 2 patients yielded the most excellent visualization in end-systole, but failed to reveal cardiac structures in detail in end-diastole. Phantom studies revealed no significant differences in image quality of 10 mm and 5 mm in thickness in the axial view 80 degree to the long axis. In the axial view 45 degree to the long axis, 10 mm-thick images were inferior to 5 mm-thick images in detecting the edge of the septum and the left ventricular wall. These results indicate that the selection of slice thickness is one of the most important determinant factors in the measurement of left ventricular wall thickness and cavity dimension. (Namekawa, K)

  1. Determination of the neutron resonance parameters for 206Pb and of the thermal neutron capture cross section for 206Pb and 209Bi

    International Nuclear Information System (INIS)

    Borella, A.

    2005-01-01

    Chapter 1 describes the motivation of the measurements (accelerator driven systems, stellar nucleosynthesis, neutron induced reactions on 206 Pb), the present status of the neutron capture data for 206 Pb and 209 Bi and the structure of this work. In Chapter 2 the basic reaction theory underlying this work is described. The neutron induced reaction mechanism and formalism are explained. The parameterisation of the cross section in terms of R-matrix theory is discussed and we put particular emphasis on the statistical behaviour of the resonance parameters and the impact of the angular distribution of gamma rays following neutron capture. The relation between experimental observables and the resonance parameters is discussed together with general comments related to resonance shape analysis. Chapter 3 is focused on the determination of resonance parameters for 206 Pb. We performed high-resolution transmission and capture measurements at the Time-Of-Flight (TOF) facility GELINA of the IRMM at Geel (B) and determined the resonance parameters. For nuclei like 206 Pb, where the total width is dominated by Γ n , the capture area allows to determine G . Transmission measurements were carried out to determine Γ n , and the statistical factor g of resonances. Before performing a Resonance Shape Analysis (RSA) on the transmission and capture data, we verified the neutron flux and resolution at GELINA. We also compared the characteristics of GELINA with those of the n-TOF facility at CERN. A special emphasis is placed on the total energy detection technique using C 6 D 6 detectors. This technique was applied for the determination of the capture cross section. To reduce systematic bias effects on the capture cross section, the response of the detectors was determined by Monte Carlo simulations, which has been validated by experiments. Using these response functions the partial capture cross sections for individual resonances of 206 Pb have been deduced, by unfolding the

  2. Displacement of popliteal sciatic nerve catheters after major foot and ankle surgery: a randomized controlled double-blinded magnetic resonance imaging study

    DEFF Research Database (Denmark)

    Hauritz, R W; Pedersen, E M; Linde, F S

    2016-01-01

    Popliteal sciatic nerve catheters (PSNCs) are associated with a high frequency of displacement. We aimed to estimate the frequency of catheter displacement after 48 h with magnetic resonance imaging (MRI) in patients with PSNCs after major foot and ankle surgery randomized to catheter insertion e...

  3. Determining Double Bond Position in Lipids Using Online Ozonolysis Coupled to Liquid Chromatography and Ion Mobility-Mass Spectrometry.

    Science.gov (United States)

    Harris, Rachel A; May, Jody C; Stinson, Craig A; Xia, Yu; McLean, John A

    2018-02-06

    The increasing focus on lipid metabolism has revealed a need for analytical techniques capable of structurally characterizing lipids with a high degree of specificity. Lipids can exist as any one of a large number of double bond positional isomers, which are indistinguishable by single-stage mass spectrometry alone. Ozonolysis reactions coupled to mass spectrometry have previously been demonstrated as a means for localizing double bonds in unsaturated lipids. Here we describe an online, solution-phase reactor using ozone produced via a low-pressure mercury lamp, which generates aldehyde products diagnostic of cleavage at a particular double bond position. This flow-cell device is utilized in conjunction with structurally selective ion mobility-mass spectrometry. The lamp-mediated reaction was found to be effective for multiple lipid species in both positive and negative ionization modes, and the conversion efficiency from precursor to product ions was tunable across a wide range (20-95%) by varying the flow rate through the ozonolysis device. Ion mobility separation of the ozonolysis products generated additional structural information and revealed the presence of saturated species in a complex mixture. The method presented here is simple, robust, and readily coupled to existing instrument platforms with minimal modifications necessary. For these reasons, application to standard lipidomic workflows is possible and aids in more comprehensive structural characterization of a myriad of lipid species.

  4. A practical guide for the design and implementation of the double-spike technique for precise determination of molybdenum isotope compositions of environmental samples.

    Science.gov (United States)

    Skierszkan, E K; Amini, M; Weis, D

    2015-03-01

    The isotopic double-spike method allows for the determination of stable isotope ratios by multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS) with accuracy and precision in the range of ∼0.02 ‰ amu(-1), but its adoption has been hindered by the perceived difficulties in double-spike calibration and implementation. To facilitate the implementation of the double-spike approach, an explanation of the calibration and validation of a (97)Mo-(100)Mo double-spike protocol is given in more detail than has been presented elsewhere. The long-term external standard reproducibility is 0.05 ‰ on δ(98/95)Mo measurements of standards. δ(98/95)Mo values for seawater and U.S. Geological Survey (USGS) reference materials SDO-1 and BCR-2 measured in this study are 2.13 ± 0.04 ‰ (2 SD, n = 3), 0.79 ± 0.05 ‰ (2 SD, n = 11), and -0.04 ± 0.10 ‰ (2 SD, n = 3) relative to the NIST-SRM-3134. The double-spike method corrects for laboratory and instrumental fractionation which are not accounted for using other mass bias correction methods. Spike/sample molar ratios between 0.4 and 0.8 provide accurate isotope measurements; outside of this range, isotope measurements are inaccurate but corrections are possible when standards and samples are spiked at a similar ratio.

  5. Numerical determination of families of three-dimensional double-symmetric periodic orbits in the restricted three-body problem. Pt. 1

    International Nuclear Information System (INIS)

    Kazantzis, P.G.

    1979-01-01

    New families of three-dimensional double-symmetric periodic orbits are determined numerically in the Sun-Jupiter case of the restricted three-body problem. These families bifurcate from the 'vertical-critical' orbits (αsub(ν) = -1, csub(ν) = 0) of the 'basic' plane families i. g 1 g 2 h, a, m and I. Further the numerical procedure employed in the determination of these families has been described and interesting results have been pointed out. Also, computer plots of the orbits of these families have been shown in conical projections. (orig.)

  6. Determination of trace uranium by resonance fluorescence method coupled with photo-catalytic technology and dual cloud point extraction.

    Science.gov (United States)

    Li, Jiekang; Li, Guirong; Han, Qian

    2016-12-05

    In this paper, two kinds of salophens (Sal) with different solubilities, Sal1 and Sal2, have been respectively synthesized, and they all can combine with uranyl to form stable complexes: [UO2(2+)-Sal1] and [UO2(2+)-Sal2]. Among them, [UO2(2+)-Sal1] was used as ligand to extract uranium in complex samples by dual cloud point extraction (dCPE), and [UO2(2+)-Sal2] was used as catalyst for the determination of uranium by photocatalytic resonance fluorescence (RF) method. The photocatalytic characteristic of [UO2(2+)-Sal2] on the oxidized pyronine Y (PRY) by potassium bromate which leads to the decrease of RF intensity of PRY were studied. The reduced value of RF intensity of reaction system (ΔF) is in proportional to the concentration of uranium (c), and a novel photo-catalytic RF method was developed for the determination of trace uranium (VI) after dCPE. The combination of photo-catalytic RF techniques and dCPE procedure endows the presented methods with enhanced sensitivity and selectivity. Under optimal conditions, the linear calibration curves range for 0.067 to 6.57ngmL(-1), the linear regression equation was ΔF=438.0 c (ngmL(-1))+175.6 with the correlation coefficient r=0.9981. The limit of detection was 0.066ngmL(-1). The proposed method was successfully applied for the separation and determination of uranium in real samples with the recoveries of 95.0-103.5%. The mechanisms of the indicator reaction and dCPE are discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Determination of metallothioneins by fluorescence and resonance light scattering strategies based on ciprofloxacin–Cu(II) system

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Lu [College of Public Health, University of South China, Hengyang 421001 (China); Wang, Yong-Sheng, E-mail: yongsheng.w@tom.com [College of Public Health, University of South China, Hengyang 421001 (China); Xue, Jin-Hua; Yang, Hui-Xian; Li, Qiu; Zhou, Bin; Wang, Jia-Cheng; Yin, Ji-Cheng; Wang, Yong-Song [College of Public Health, University of South China, Hengyang 421001 (China); Xiao, Xi-Lin [College of Chemistry and Chemical Engineering, University of South China, Hengyang 421001 (China)

    2013-06-15

    Based on ciprofloxacin (CIP)–Cu(II) system, the novel methods for the detection of metallothioneins (MTs) have been developed by fluorescence (FL) and resonance light scattering (RLS) strategies. The FL strategy avoids the label and derivatization steps in common methods, while the RLS strategy can be applied for determining bio-macromolecules and small molecules without native fluorescence. The response signals linearly correlated with the concentration of MTs over the ranges of 1.03×10{sup −8}–1.23×10{sup −6} mol L{sup −1} for FL, and of 2.56×10{sup −7}–1.54×10{sup −6} mol L{sup −1} for RLS. The limits of detection (LOD) are 3.1×10{sup −9} mol L{sup −1} for FL and 7.68×10{sup −8} mol L{sup −1} for RLS. This study represents the comparison of these two methods using the same CIP–Cu{sup 2+}–MTs system. They not only allow practical application for MTs detection but also serve as a potential choice for the operators according to their concrete needs. In addition, the mechanisms for FL and RLS enhancement of the system were also discussed. -- Highlights: ► Determination of MTs was developed based on CIP–Cu(II) system by FL and RLS strategies. ► FL strategy provides lower limit of detection and wider linear range, and avoids the label and derivatization steps. ► RLS strategy can be applied for determining bio-macromolecules and small molecules. ► The mechanism of interaction of MTs with CIP–Cu(II) chelate was discussed.

  8. Cardiac effects of MDMA on the metabolic profile determined with 1H-magnetic resonance spectroscopy in the rat†

    Science.gov (United States)

    Perrine, Shane A.; Michaels, Mark S.; Ghoddoussi, Farhad; Hyde, Elisabeth M.; Tancer, Manuel E.; Galloway, Matthew P.

    2010-01-01

    Despite the potential for deleterious (even fatal) effects on cardiac physiology, 3,4-methylenedioxymethamphetamine (MDMA; ecstasy) abuse abounds driven mainly by its euphoric effects. Acute exposure to MDMA has profound cardiovascular effects on blood pressure and heart rate in humans and animals. To determine the effects of MDMA on cardiac metabolites in rats, MDMA (0, 5, or 10 mg/kg) was injected every 2 h for a total of four injections; animals were sacrificed 2 h after the last injection (8 h drug exposure), and their hearts removed and tissue samples from left ventricular wall dissected. High resolution magic angle spinning proton magnetic resonance spectroscopy (1H-MRS) at 11.7 T, a specialized version of MRS aptly suited for analysis of semi-solid materials such as intact tissue samples, was used to measure the cardiac metabolomic profile, including alanine, lactate, succinate, creatine, and carnitine, in heart tissue from rats treated with MDMA. MDMA effects on MR-visible choline, glutamate, glutamine, and taurine were also determined. Body temperature was measured following each MDMA administration and serotonin and norepinephrine (NE) levels were measured by high pressure liquid chromatography (HPLC) in heart tissue from treated animals. MDMA significantly and dose-dependently increased body temperature, a hallmark of amphetamines. Serotonin, but not NE, levels were significantly and dose-dependently decreased by MDMA in the heart wall. MDMA significantly altered the MR-visible profile with an increase in carnitine and no change in other key compounds involved in cardiomyocyte energy metabolomics. Finally, choline levels were significantly decreased by MDMA in heart. The results are consistent with the notion that MDMA has significant effects on cardiovascular serotonergic tone and disrupts the metabolic homeostasis of energy regulation in cardiac tissue, potentially increasing utilization of fatty acid metabolism. The contributions of serotonergic

  9. Cardiac effects of MDMA on the metabolic profile determined with 1H-magnetic resonance spectroscopy in the rat.

    Science.gov (United States)

    Perrine, Shane A; Michaels, Mark S; Ghoddoussi, Farhad; Hyde, Elisabeth M; Tancer, Manuel E; Galloway, Matthew P

    2009-05-01

    Despite the potential for deleterious (even fatal) effects on cardiac physiology, 3,4-methylenedioxymethamphetamine (MDMA; ecstasy) abuse abounds driven mainly by its euphoric effects. Acute exposure to MDMA has profound cardiovascular effects on blood pressure and heart rate in humans and animals. To determine the effects of MDMA on cardiac metabolites in rats, MDMA (0, 5, or 10 mg/kg) was injected every 2 h for a total of four injections; animals were sacrificed 2 h after the last injection (8 h drug exposure), and their hearts removed and tissue samples from left ventricular wall dissected. High resolution magic angle spinning proton magnetic resonance spectroscopy ((1)H-MRS) at 11.7 T, a specialized version of MRS aptly suited for analysis of semi-solid materials such as intact tissue samples, was used to measure the cardiac metabolomic profile, including alanine, lactate, succinate, creatine, and carnitine, in heart tissue from rats treated with MDMA. MDMA effects on MR-visible choline, glutamate, glutamine, and taurine were also determined. Body temperature was measured following each MDMA administration and serotonin and norepinephrine (NE) levels were measured by high pressure liquid chromatography (HPLC) in heart tissue from treated animals. MDMA significantly and dose-dependently increased body temperature, a hallmark of amphetamines. Serotonin, but not NE, levels were significantly and dose-dependently decreased by MDMA in the heart wall. MDMA significantly altered the MR-visible profile with an increase in carnitine and no change in other key compounds involved in cardiomyocyte energy metabolomics. Finally, choline levels were significantly decreased by MDMA in heart. The results are consistent with the notion that MDMA has significant effects on cardiovascular serotonergic tone and disrupts the metabolic homeostasis of energy regulation in cardiac tissue, potentially increasing utilization of fatty acid metabolism. The contributions of serotonergic

  10. Determination of haloacetic acids in water using layered double hydroxides as a sorbent in dispersive solid-phase extraction followed by liquid chromatography with tandem mass spectrometry.

    Science.gov (United States)

    Alsharaa, Abdulnaser; Sajid, Muhammad; Basheer, Chanbasha; Alhooshani, Khalid; Lee, Hian Kee

    2016-09-01

    In the present study, highly efficient and simple dispersive solid-phase extraction procedure for the determination of haloacetic acids in water samples has been established. Three different types of layered double hydroxides were synthesized and used as a sorbent in dispersive solid-phase extraction. Due to the interesting behavior of layered double hydroxides in an acidic medium (pH˂4), the analyte elution step was not needed; the layered double hydroxides are simply dissolved in acid immediately after extraction to release the analytes which are then directly introduced into a liquid chromatography with tandem mass spectrometry system for analysis. Several dispersive solid-phase extraction parameters were optimized to increase the extraction efficiency of haloacetic acids such as temperature, extraction time and pH. Under optimum conditions, good linearity was achieved over the concentration range of 0.05-100 μg/L with detection limits in the range of 0.006-0.05 μg/L. The relative standard deviations were 0.33-3.64% (n = 6). The proposed method was applied to different water samples collected from a drinking water plant to determine the concentrations of haloacetic acids. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Determination of Formulation Conditions Allowing Double Emulsions Stabilized by PGPR and Sodium Caseinate to Be Used as Capsules.

    Science.gov (United States)

    Nollet, Maxime; Laurichesse, Eric; Besse, Samantha; Soubabère, Olivier; Schmitt, Véronique

    2018-02-27

    Water-in-oil-in-water (W 1 /O/W 2 ) double emulsions stabilized by polyglycerol polyricinoleate (PGPR), a lipophilic food grade small polymer, and sodium caseinate, a hydrophilic milk protein, were developed to encapsulate vitamin B12, a model hydrophilic substance easy to titrate. Using rheology, sensitive to drop size evolution and water fluxes, static light scattering, and microscopy both giving the evolution of drops' size and vitamin B12 titration assessing the encapsulation, we were able to detect independently the double emulsion drop size, the encapsulation loss, and the flux of water as a function of time. By differentiating the PGPR required to cover the W 1 -droplets' surface from PGPR in excess in the oil phase, we built a PGPR-inner droplet volume fraction diagram highlighting the domains where the double emulsion is stable toward encapsulation and/or water fluxes. We demonstrated the key role played by nonadsorbed PGPR concentration in the intermediate sunflower oil phase on the emulsion stability while, surprisingly, the inner droplet volume fraction had no effect on the emulsion stability. At low PGPR concentration, a release of vitamin B12 was observed and the leakage mechanism of coalescence between droplets and oil-water interface of the oily drops (also called globules hereafter), was identified using confocal microscopy. For high enough PGPR content, the emulsions were stable and may therefore serve as efficient capsules without need of an additional gelling, thickening, complexion or interface rigidifying agent. We generalized these results with the encapsulation of an insecticide: Cydia pomonella granulovirus used in organic arboriculture.

  12. Dating the onset of some mutations in myostatin gene determining the double muscled phenotype in beef cattle

    Directory of Open Access Journals (Sweden)

    A. Nardone

    2011-03-01

    Full Text Available Growth differentiation factor 8 (GDF8 or myostatin is a member of the transforming growth factor β (TGF-β superfamily, which includes proteins that mediate key events in cell growth and development through signal transduction. In the absence of myostatin, the skeletal musculature of mice is two to three times greater in mass than that of wild-type mice (McPherron et al., 1997. Several cattle breeds are characterized by double muscling phenotype and GDF8 has been extensively investigated in cattle.A large number of variants have been identified in these species,most of which are silent or neutral.........

  13. Sharpening m{sub T2} cusps. The mass determination of semi-invisibly decaying particles from a resonance

    Energy Technology Data Exchange (ETDEWEB)

    Harland-Lang, Lucian A. [Durham Univ. (United Kingdom). Dept. of Physics; Durham Univ. (United Kingdom). Inst. for Particle Physics Phenomenology; Kom, Chun-Hay [Liverpool Univ. (United Kingdom). Dept. of Mathematical Sciences; Sakurai, Kazuki [King' s College London (United Kingdom). Theoretical Particle Physics and Cosmology Group; Tonini, Marco [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2013-12-15

    We revisit mass determination techniques for the minimum symmetric event topology, namely X pair production followed by X{yields}lN, where X and N are unknown particles with the masses to be measured, and N is an invisible particle. We consider separate scenarios, with different initial constraints on the invisible particle momenta, and present a systematic method to identify the kinematically allowed mass regions in the (m{sub N},m{sub X}) plane. These allowed regions exhibit a cusp structure at the true mass point, which is equivalent to the one observed in the m{sub T2} endpoints in certain cases. By considering the boundary of the allowed mass region we systematically define kinematical variables which can be used in measuring the unknown masses, and find a new expression for the m{sub T2} variable as well as its inverse. We explicitly apply our method to the case that X is pair produced from a resonance, and as a case study, we consider the process pp {yields} A {yields} {chi}{sup +}{sub 1}{chi}{sup -}{sub 1}, followed by {chi}{sup {+-}}{sub 1} {yields} l{nu}, in the minimal supersymmetric standard model and show that our method provides a precise measurement of the chargino and sneutrino masses, m{sub X} and m{sub N}, at 14 TeV LHC with 300 fb{sup -1} luminosity.

  14. A simple and sensitive immunoassay for the determination of human chorionic gonadotropin by graphene-based chemiluminescence resonance energy transfer.

    Science.gov (United States)

    Lei, Jiuqian; Jing, Tao; Zhou, Tingting; Zhou, Yusun; Wu, Wei; Mei, Surong; Zhou, Yikai

    2014-04-15

    In this study, we report a strategy of chemiluminescence resonance energy transfer (CRET) using graphene as an efficient long-range energy acceptor. Magnetic nanoparticles were also used in CRET for simple magnetic separation and immobilization of horseradish peroxidase (HRP)-labeled anti-HCG antibody. In the design of CRET system, the sandwich-type immunocomplex was formed between human chorionic gonadotropin (HCG, antigen) and two different antibodies bridged the magnetic nanoparticles and graphene (acceptors), which led to the occurrence of CRET from chemiluminescence light source to graphene. After optimizing the experimental conditions, the quenching of chemiluminescence signal depended linearly on the concentration of HCG in the range of 0.1 mIU mL(-1)-10 mIU mL(-1) and the detection limit was 0.06 mIU mL(-1). The proposed method was successfully applied for the determination of HCG levels in saliva and serum samples, and the results were in good agreement with the plate ELISA with colorimetric detection. It could also be developed for detection of other antigen-antibody immune complexes by using the corresponding antigens and respective antibodies. © 2013 Published by Elsevier B.V.

  15. Determination of the inferior border of the thecal sac using magnetic resonance imaging: implications on radiation therapy treatment planning

    International Nuclear Information System (INIS)

    Scharf, Carole B.; Paulino, Arnold C.; Goldberg, Kenneth N.

    1998-01-01

    Purpose: To determine whether the traditional teaching of placing the caudal border of the spinal field at the S2-S3 interspace in children receiving craniospinal irradiation (CSI) is appropriate. Methods and Materials: Twenty-three children had magnetic resonance imaging (MRI) of the spine with gadolinium prior to craniospinal irradiation at one institution. Thecal sac termination using MRI was determined by drawing a perpendicular line from the point of convergence of dural margins to the corresponding vertebral body. Results: Location of thecal sac termination varied from mid-S1 to low S3 vertebral body, with the most frequent site at the upper S2 vertebral level. Only 2 of 23 (8.7%) children had thecal sac terminations below the S2-S3 interspace. For the nine patients with neuraxis disease, none had thecal sac terminations below the S2-S3 interspace. In seven of the nine patients who had neuraxis seeding at initial presentation, MRI of the spine after CSI was performed and showed that thecal sac termination was lower after radiation therapy in two children, higher in one, and the same in four. Conclusions: In 2 of 23 children (8.7%), placement of the inferior border at the bottom of the S2 vertebral body would have missed the entire thecal sac. Treatment to the entire neuraxis with adequate coverage of distal spinal theca can be achieved by using MRI. Individualized spinal fields using the MRI may help minimize radiation scatter to the gonads while adequately covering the target volume

  16. Highly sensitive and selective determination of hydrogen sulfide by resonance light scattering technique based on silver nanoparticles.

    Science.gov (United States)

    Kuang, Yangfang; Chen, Shu; Long, Yunfei

    2017-06-01

    We have developed a green approach to prepare DNA-templated silver nanoparticles (Ag-NPs) from the direct reaction between Ag + and ascorbic acid in the presence of DNA and sodium hydroxide. The Ag-NPs showed strong resonance light scattering (RLS) intensity property. Then, the interaction between hydrogen sulfide (H 2 S) and Ag-NPs was studied by measuring their RLS spectra. The results showed that there is a strong interaction between Ag-NPs and H 2 S, which resulted in a decrease in the size of Ag-NPs and a decrease in the RLS intensity of the Ag-NPs solution at the wavelength of 467 nm. The results demonstrated that the RLS technique offers a sensitive and simple tool for investigating the interaction between Ag-NPs and H 2 S, which can be applied to detect H 2 S with high sensitivity and selectivity without complex readout equipment. The linear range for H 2 S determination was found to be the range from 5.0 × 10 -9 to 1.0 × 10 -7  mol L -1 , and the detection limit (3σ/k) was 2.8 × 10 -9  mol L -1 . Moreover, the proposed method was applied for the determination of H 2 S in natural water samples with satisfactory results. Graphical abstract The application of Ag-NPs in H 2 S detection.

  17. Inter- and intra-rater reproducibility of semiautomatic determination of volume parameters in cardiac magnetic resonance imaging

    International Nuclear Information System (INIS)

    Trieb, Thomas; Glodny, Bernhard; Scheiblhofer, Martin; Wolf, Christian; Metzler, Bernhard; Pachinger, Otmar; Jaschke, Werner R.; Schocke, Michael F.H.

    2008-01-01

    Purpose: The purpose of this study was to evaluate inter- and intra-rater reproducibility in volume assessment using cardiac magnetic resonance imaging (CMRI). Methods: Twenty-five healthy volunteers and 106 patients were included into this retrospective study and received CMRI. The patients were divided in three groups (group I, 80 patients with arrhythmia; group II, 20 patients with cardiomyopathy; group III, 6 patients after correction of septum defects). Therefore, the images were semiautomatically segmented by an experienced and an unexperienced radiologists. The analysis of end-diastolic volume (EDV), end-systolic volume (ESV) and stroke volume (SV) as well as ejection fraction (EF) and myocardial mass (MM) were performed twice by an experienced and an unexperienced radiologists. The intra-class correlation coefficients (ICC) were determined for the evaluation of inter- and intra-rater variance. Results: The intra-rater reproducibility for determination of EF, ESV, EDV and MM was excellent with ICCs ranging from 0.88 to 0.99 (all p < 0.001). The inter-observer reproducibility for these parameters was also excellent with ICCs ranging from 0.91 to 0.98 (all p < 0.001). The assessment of the SV showed an excellent intra-rater agreement with ICCs of 0.96 and 0.92 (both p < 0.001), but only a moderate ICC for the inter-rater reproducibility (0.54, p < 0.001). Conclusions: Our study shows that assessment of cardiac volumes can be performed on CMRIs with an excellent reproducibility by both experienced and unexperienced investigators

  18. Determination of neutron resonance parameters of Neptunium 237 between 0 and 500 eV. The covariance matrices of statistical and of systematic origin, relating the resonance parameters, are also given

    International Nuclear Information System (INIS)

    Lepretre, A.; Herault, N.; Brusegan, A.; Noguere, G.; Siegler, P.

    2002-12-01

    This report is a follow up of the report CEA DAPNIA/SPHN-99-04T of Vincent Gressier. In the frame of a collaboration between the 'Commissariat a l'Energie Atomique (CEA)' and the Institute for Reference Materials and Measurement (IRMM, Geel, Belgique), the resonance parameters of neptunium 237 have been determined in the energy interval between 0 and 500 eV. These parameters have been obtained by using the Refit code in analysing simultaneously three transmission experiments. The covariance matrix of statistical origin is provided. A new method, based on various sensitivity studies is proposed for determining also the covariance matrix of systematic origin, relating the resonance parameters. From an experimental viewpoint, the study indicated that, with a large probability, the background spectrum has structure. A two dimensional profiler for the neutron density has been proved feasible. Such a profiler could, among others, demonstrate the existence of the structured background. (authors)

  19. Analytical determination of Kondo and Fano resonances of electron Green's function in a single-level quantum dot

    International Nuclear Information System (INIS)

    Nguyen Bich Ha; Nguyen Van Hop

    2009-01-01

    The Kondo and Fano resonances in the two-point Green's function of the single-level quantum dot were found and investigated in many previous works by means of different numerical calculation methods. In this work we present the derivation of the analytical expressions of resonance terms in the expression of the two-point Green's function. For that purpose the system of Dyson equations for the two-point nonequilibrium Green's functions in the complex-time Keldysh formalism was established in the second order with respect to the tunneling coupling constants and the mean field approximation. This system of Dyson equations was solved exactly and the analytical expressions of the resonance terms are derived. The conditions for the existence of Kondo or Fano resonances are found.

  20. Nature of isomerism of solid isothiourea salts, inhibitors of nitric oxide synthases, as studied by 1H-14N nuclear quadrupole double resonance, X-ray, and density functional theory/quantum theory of atoms in molecules.

    Science.gov (United States)

    Latosińska, J N; Latosińska, M; Seliger, J; Žagar, V; Maurin, J K; Kazimierczuk, Z

    2012-02-09

    Isothioureas, inhibitors of nitric oxide synthases, have been studied experimentally in solid state by nuclear quadrupole double resonance (NQDR) and X-ray methods and theoretically by the quantum theory of atoms in molecules/density functional theory. Resonance frequencies on (14)N have been detected and assigned to particular nitrogen sites in each molecule. The crystal packings of (S)-3,4-dichlorobenzyl-N-methylisothiouronium chloride with the disordered chlorine positions in benzene ring and (S)-butyloisothiouronium bromide have been resolved in X-ray diffraction studies. (14)N NQDR spectra have been found good indicators of isomer type and strength of intra- or intermolecular N-H···X (X = Cl, Br) interactions. From among all salts studied, only for (S)-2,3,4,5,6-pentabromobenzylisothiouronium chloride are both nitrogen sites equivalent, which has been explained by the slow exchange. This unique structural feature can be a key factor in the high biological activity of (S)-2,3,4,5,6-pentabromobenzylisothiouronium salts.

  1. First measurement of target and double spin asymmetries for polarized e- polarized p --> e p pi0 in the nucleon resonance region above the Delta(1232)

    Energy Technology Data Exchange (ETDEWEB)

    Biselli, Angela; Burkert, Volker; Amaryan, Moscov; Amaryan, Moskov; Asryan, Gegham; Avagyan, Harutyun; Baghdasaryan, Hovhannes; Baillie, Nathan; Ball, J.P.; Ball, Jacques; Baltzell, Nathan; Battaglieri, Marco; Bedlinskiy, Ivan; Bellis, Matthew; Benmouna, Nawal; Berman, Barry; Blaszczyk, Lukasz; Bookwalter, Craig; Boyarinov, Sergey; Bosted, Peter; Bradford, Robert; Branford, Derek; Briscoe, William; Brooks, William; Bultmann, S.; Bueltmann, Stephen; Butuceanu, Cornel; Calarco, John; Careccia, Sharon; Carman, Daniel; Casey, Liam; Chen, Shifeng; Cheng, Lu; Cole, Philip; Collins, Patrick; Coltharp, Philip; Crabb, Donald; Crede, Volker; Dale, Daniel; Dashyan, Natalya; De Masi, Rita; De Vita, Raffaella; De Sanctis, Enzo; Degtiarenko, Pavel; Deur, Alexandre; Dhamija, Seema; Dickson, Richard; Djalali, Chaden; Dodge, Gail; Doughty, David; Dugger, Michael; Dzyubak, Oleksandr; Egiyan, Hovanes; Elfassi, Lamiaa; Elouadrhiri, Latifa; Eugenio, Paul; Fedotov, Gleb; Feuerbach, Robert; Fersch, Robert; Forest, Tony; Fradi, Ahmed; Garcon, Michel; Gavalian, Gagik; Gevorgyan, Nerses; Gilfoyle, Gerard; Giovanetti, Kevin; Girod, Francois-Xavier; Goetz, John; Gohn, Wesley; Gothe, Ralf; Graham, Lewis; Griffioen, Keith; Guidal, Michel; Guler, Nevzat; Guo, Lei; Gyurjyan, Vardan; Hafidi, Kawtar; Hakobyan, Hayk; Hanretty, Charles; Hassall, Neil; Hicks, Kenneth; Hleiqawi, Ishaq; Holtrop, Maurik; Hyde, Charles; Ilieva, Yordanka; Ireland, David; Ishkhanov, Boris; Isupov, Evgeny; Ito, Mark; Jenkins, David; Jo, Hyon-Suk; Johnstone, John; Joo, Kyungseon; Juengst, Henry; Kalantarians, Narbe; Keller, Dustin; Kellie, James; Khandaker, Mahbubul; Kim, Wooyoung; Klein, Andreas; Klein, Franz; Kossov, Mikhail; Krahn, Zebulun; Kubarovsky, Valery; Kuhn, Joachim; Kuhn, Sebastian; Kuleshov, Sergey; Kuznetsov, Viacheslav; Lachniet, Jeff; Laget, Jean; Langheinrich, Jorn; Lawrence, David; Livingston, Kenneth; Lu, Haiyun; MacCormick, Marion; Markov, Nikolai; Mattione, Paul; McKinnon, Bryan; McNabb, John; Mecking, Bernhard; Mestayer, Mac; Meyer, Curtis; Mibe, Tsutomu; Mikhaylov, Konstantin; Mirazita, Marco; Mokeev, Viktor; Moreno, Brahim; Moriya, Kei; Morrow, Steven; Moteabbed, Maryam; Munevar Espitia, Edwin; Mutchler, Gordon; Nadel-Turonski, Pawel; Nasseripour, Rakhsha; Niccolai, Silvia; Niculescu, Gabriel; Niculescu, Maria-Ioana; Niczyporuk, Bogdan; Niroula, Megh; Niyazov, Rustam; Nozar, Mina; Osipenko, Mikhail; Ostrovidov, Alexander; Park, Kil; Park, Seungkyung; Pasyuk, Evgueni; Paterson, Craig; Pereira, Sergio; Pierce, Joshua; Pivnyuk, Nikolay; Pogorelko, Oleg; Pozdnyakov, Sergey; Price, John; Prok, Yelena; Protopopescu, Dan; Raue, Brian; Ricco, Giovanni; Ripani, Marco; Ritchie, Barry; Rosner, Guenther; Rossi, Patrizia; Sabatie, Franck; Saini, Mukesh; Salamanca, Julian; Salgado, Carlos; Santoro, Joseph; Sapunenko, Vladimir; Schott, Diane; Schumacher, Reinhard; Serov, Vladimir; Sharabian, Youri; Sharov, Dmitri; Shvedunov, Nikolay; Smith, Elton; Sober, Daniel; Sokhan, Daria; Stavinskiy, Aleksey; Stepanyan, Samuel; Stepanyan, Stepan; Stokes, Burnham; Stoler, Paul; Strakovski, Igor; Strauch, Steffen; Taiuti, Mauro; Tedeschi, David; Tkabladze, Avtandil; Tkachenko, Svyatoslav; Todor, Luminita; Ungaro, Maurizio; Vineyard, Michael; Vlassov, Alexander; Watts, Daniel; Weinstein, Lawrence; Weygand, Dennis; Williams, M.; Wolin, Elliott; Wood, Michael; Yegneswaran, Amrit; Yurov, Mikhail; Zana, Lorenzo; Zhang, Jixie; Zhao, Bo; Zhao, Zhiwen

    2008-10-01

    DOI: http://dx.doi.org/10.1103/PhysRevC.78.045204
    The exclusive channel polarized proton(polarized e,e prime p)pi0 was studied in the first and second nucleon resonance regions in the Q2 range from 0.187 to 0.770 GeV2 at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). Longitudinal target and beam-target asymmetries were extracted over a large range of center-of-mass angles of the pi0 and compared to the unitary isobar model MAID, the dynamic model by Sato and Lee, and the dynamic model DMT. A strong sensitivity to individual models was observed, in particular for the target asymmetry and in the higher invariant mass region. This data set, once included in the global fits of the above models, is expected to place strong constraints on the electrocoupling amplitudes A_{1/2} and S_{1/2} for the Roper resonance N(1400)P11, and the N(1535)S11 and N(1520)D13 states.

  2. Topology of the interactions pattern in pharmaceutically relevant polymorphs of methylxanthines (caffeine, theobromine, and theophiline): combined experimental (¹H-¹⁴N nuclear quadrupole double resonance) and computational (DFT and Hirshfeld-based) study.

    Science.gov (United States)

    Latosińska, Jolanta Natalia; Latosińska, Magdalena; Olejniczak, Grzegorz A; Seliger, Janez; Žagar, Veselko

    2014-09-22

    Three anhydrous methylxanthines: caffeine (1,3,7-trimethylxanthine; 1,3,7-trimethyl-1H-purine-2,6-(3H,7H)-dione) and its two metabolites theophylline (1,3-dimethylxanthine; 1,3-dimethyl-7H-purine-2,6-dione) and theobromine (3,7-dimethyl-xanthine; 3,7-dimethyl-7H-purine-2,6-dione), which reveal multifaceted therapeutic potential, have been studied experimentally in solid state by (1)H-(14)N NMR-NQR (nuclear magnetic resonance-nuclear quadrupole resonance) double resonance (NQDR). For each compound the complete NQR spectrum consisting of 12 lines was recorded. The multiplicity of NQR lines indicates the presence of a stable β form of anhydrous caffeine at 233 K and stable form II of anhydrous theobromine at 213 K. The assignment of signals detected in NQR experiment to particular nitrogen atoms was made on the basis of quantum chemistry calculations performed for monomer, cluster, and solid at the DFT/GGA/BLYP/DPD level. The shifts due to crystal packing interactions were evaluated, and the multiplets detected by NQR were assigned to N(9) in theobromine and N(1) and N(9) in caffeine. The ordering theobromine > theophylline > caffeine site and theophylline theobromine theobromine) to π···π stacking (caffeine). Substantial differences in the intermolecular interactions in stable forms of methylxanthines differing in methylation (site or number) were analyzed within the Hirshfeld surface-based approach. The analysis of local environment of the nitrogen nucleus permitted drawing some conclusions on the nature of the interactions required for effective processes of recognition and binding of a given methylxanthine to A1-A(2A) receptor (target for caffeine in the brain). Although the interactions responsible for linking neighboring methylxanthines molecules in crystals and methylxanthines with targets in the human organism can differ significantly, the knowledge of the topology of interactions provides reliable preliminary information about the nature of this binding.

  3. Conformational Entropy of FK506 Binding to FKBP12 Determined by Nuclear Magnetic Resonance Relaxation and Molecular Dynamics Simulations.

    Science.gov (United States)

    Solomentsev, Gleb; Diehl, Carl; Akke, Mikael

    2018-03-06

    FKBP12 (FK506 binding protein 12 kDa) is an important drug target. Nuclear magnetic resonance (NMR) order parameters, describing amplitudes of motion on the pico- to nanosecond time scale, can provide estimates of changes in conformational entropy upon ligand binding. Here we report backbone and methyl-axis order parameters of the apo and FK506-bound forms of FKBP12, based on 15 N and 2 H NMR relaxation. Binding of FK506 to FKBP12 results in localized changes in order parameters, notably for the backbone of residues E54 and I56 and the side chains of I56, I90, and I91, all positioned in the binding site. The order parameters increase slightly upon FK506 binding, indicating an unfavorable entropic contribution to binding of TΔ S = -18 ± 2 kJ/mol at 293 K. Molecular dynamics simulations indicate a change in conformational entropy, associated with all dihedral angles, of TΔ S = -26 ± 9 kJ/mol. Both these values are significant compared to the total entropy of binding determined by isothermal titration calorimetry and referenced to a reactant concentration of 1 mM ( TΔ S = -29 ± 1 kJ/mol). Our results reveal subtle differences in the response to ligand binding compared to that of the previously studied rapamycin-FKBP12 complex, despite the high degree of structural homology between the two complexes and their nearly identical ligand-FKBP12 interactions. These results highlight the delicate dependence of protein dynamics on drug interactions, which goes beyond the view provided by static structures, and reinforce the notion that protein conformational entropy can make important contributions to the free energy of ligand binding.

  4. Diffusion-weighted magnetic resonance imaging with apparent diffusion coefficient (ADC) determination in normal and pathological fetal kidneys.

    Science.gov (United States)

    Chaumoitre, K; Colavolpe, N; Shojai, R; Sarran, A; D' Ercole, C; Panuel, M

    2007-01-01

    To assess the use of diffusion-weighted magnetic resonance imaging (DW-MRI) in the evaluation of the fetal kidney and to estimate age-dependent changes in the apparent diffusion coefficient (ADC) of normal and pathological fetal kidneys. DW-MRI was performed on a 1.5-T machine at 23-38 gestational weeks in 51 pregnant women in whom the fetal kidneys were normal and in 10 whose fetuses had renal pathology (three with suspected nephropathy, three with renal tract dilatation, one with unilateral renal venous thrombosis, and three with twin-twin transfusion syndrome (TTTS)). The ADC was measured in an approximately 1-cm2 region of interest within the renal parenchyma. ADC values in normal renal parenchyma ranged from 1.1 to 1.8 10(-3) mm2 s-1. There was no significant age-dependent change in the ADC of normal kidneys. In cases of nephropathy, the ADC value was not always pathological but an ADC map could show abnormal findings. In cases of dilatation, the ADC value was difficult to determine when the dilatation was huge. In cases of TTTS, the ADC of the donor twin was higher than that of the recipient twin and the difference seemed to be related to the severity of the syndrome. Evaluation of the ADC for fetal kidneys is feasible. Fetal measurement of the ADC value and ADC maps may be useful tools with which to explore the fetal kidney when used in conjunction with current methods. DW-MR images, ADC value and ADC map seem to be useful in cases of suspected nephropathy (hyperechoic kidneys), dilated kidney and vascular pathology (renal venous thrombosis, TTTS). Copyright (c) 2006 ISUOG.

  5. Determining the risks of magnetic resonance imaging at 1.5 tesla for patients with pacemakers and implantable cardioverter defibrillators.

    Science.gov (United States)

    Cohen, Jennifer D; Costa, Heather S; Russo, Robert J

    2012-12-01

    Conventional pacemaker and implantable cardioverter-defibrillator product labeling currently cautions against exposure to magnetic resonance imaging (MRI). However, there is a growing clinical need for MRI, without an acceptable alternative imaging modality in many patients with cardiac devices. The purpose of this study was to determine the risk of MRI at 1.5 T for patients with cardiac devices by measuring the frequency of device failures and clinically relevant device parameter changes. Data from a single-center retrospective review of 109 patients with pacemakers and implantable cardioverter-defibrillators (the MRI group) who underwent 125 clinically indicated MRI studies were compared to data from a prospective cohort of 50 patients with cardiac devices who did not undergo MRI (the control group). In the MRI group, there were no deaths, device failures requiring generator or lead replacement, induced arrhythmias, losses of capture, or electrical reset episodes. Decreases in battery voltage of ≥0.04 V occurred in 4%, pacing threshold increases of ≥0.5 V in 3%, and pacing lead impedance changes of ≥50 Ω in 6%. Although there were statistically significant differences between the MRI and control groups for the mean change in pacing lead impedance (-6.2 ± 23.9 vs 3.0 ± 22.1 Ω) and left ventricular pacing threshold (-0.1 ± 0.3 vs 0.1 ± 0.2 V), these differences were not clinically important. In conclusion, MRI in patients with cardiac devices resulted in no device or lead failures. A small number of clinically relevant changes in device parameter measurements were noted. However, these changes were similar to those in a control group of patients who did not undergo MRI. Copyright © 2012 Elsevier Inc. All rights reserved.

  6. Determination of the inferior border of the thecal sac using magnetic resonance imaging: implications on craniospinal irradiation

    International Nuclear Information System (INIS)

    Scharf, Carole B.; Goldberg, Kenneth; Paulino, Arnold C.

    1996-01-01

    Purpose: Craniospinal irradiation (CSI) is employed in medulloblastoma and other intracranial malignancies that can seed the neuro axis. Care must be taken to adequately cover the entire craniospinal axis, including the distal thecal sac. The inferior border of the craniospinal field has traditionally been placed at the bottom of the S2 vertebra. The purpose of this study is to review the level of thecal sac termination in children undergoing CSI using Magnetic Resonance Imaging (MRI). Methods and Materials: From (12(87)) to (10(95)), 22 children were treated with CSI at one institution. All underwent pre-treatment MRI of the spine with Gadolinium as part of their evaluation. The median age was 9 years (range, 31 months to 18 years), and there were 14 males and 8 females. The diagnosis was medulloblastoma in 14 patients, primitive neuroectodermal tumor of the cerebrum in 3, germinoma in 2, pineoblastoma in 1, leptomeningeal gliomatosis in 1 and glioblastoma multiform in 1. All spinal MRIs were reviewed by both neuro radiologist and radiation oncologist to accurately determine the level of thecal sac termination which was obtained by drawing a horizontal line from the lower limit of the spinal theca to the corresponding adjacent vertebral body. Results: The thecal sac termination varied from mid S1 to lower S3. It was located at mid S1 in 1 patient, lower S1 in 3, S1-2 junction in 3, upper S2 in 5, mid S2 in 3, lower S2 in 3, S2-3 junction in 2, upper S3 in 1 and lower S3 in 1. Only (2(22)) patients (9%) had thecal sac terminations below the S2-3 junction. Eight patients had spinal axis involvement and their thecal sac terminations were all above the S2-3 junction. There was no correlation between the level of termination and age, gender or histology. Conclusions: The majority of patients (91%) will have termination of the thecal sac above S3, and therefore placement of the inferior border of the spinal field at the S2-3 junction with a 1 cm caudal margin will be

  7. Resonance phenomenon in classical cepheids

    International Nuclear Information System (INIS)

    Takeuti, Mine; Aikawa, Toshiki

    1981-01-01

    To investigate resonance phenomenon in classical cepheids, the non-linear radial oscillation of stars is studied based on the assumption that the non-adiabatic perturbation is expressed in terms of van der Pol's type damping. Two- and three-wave resonance in this system is applied to classical cepheids to describe their bump and double-mode behavior. The phase of bump and the depression of amplitude are explained for bump cepheids. The double-periodicity is shown by the enhancement of the third overtone in three-wave resonance. Non-linear effect on resonant period is also discussed briefly. (author)

  8. Contribution to the determination of the double angular and energy differential neutron albedo. Application to the propagation in lacunar medium

    International Nuclear Information System (INIS)

    Litaize, O.

    2000-01-01

    The goal of this thesis is to study the neutron propagation by reflection from lacunar medium interfaces. The most efficient method to calculate this type of propagation is to use the concept of albedo. Actual version of NARCISSE code uses a simple formulation of angular differential albedos and so, can only treat single reflections. Multiple reflections treatment needs the knowledge of neutron spectrum after reflection. This energetic information is contained in double angular and energy differential albedos. The first step of this study consists to generate these albedos for various materials. Several methods have been tested and the Monte Carlo method was retained. A new estimator has been developed and validated in the Mote Carlo transport code TRIPOLI-4. It computes, during the simulation of the neutron history, the angular and energy reflection probability at each collision site. The second step consists to generate an interpolation scheme and albedo libraries for various materials. A new version of NARCISSE was developed to use these libraries and the interpolation module. Spectrum and dose rates comparisons were made between codes to validate these albedos. The neutron propagation by multiple reflections can be studied now, by using this new version of Narcisse. (author)

  9. Preparation Of Liquid Phase-Double Antibodies Radioimmunoassay For The In Vitro Determination Of Prolactin Hormone In Human Serum

    International Nuclear Information System (INIS)

    MEHANY, N.L.; EL-KOLALY, M.T.; EBEID, N.H.; MEKY, N.H.

    2009-01-01

    In the present study, the preparation of the basic reagents of prolactin (PRL) radioimmunoassay (RIA) technique using liquid phase double antibody with low cost is considered to be the main objective. Three primary components were prepared and characterized to obtain valid and accurate system. These components were polyclonal antibody (anti-PRL), 125 I-prolactin ( 125 I-PRL) radio-iodinated tracer and PRL standards. The production of polyclonal anti-PRL was undertaken by immunizing eight males of white New-Zealand rabbits (two groups) with highly purified PRL antigen through primary injection and five booster doses subcutaneously and intramuscular. The preparation of radio-iodinated ( 1 '2 5 I-PRL) tracer was carried out using chloramine-T method. The preparation of PRL standards were carried out using highly purified PRL antigen in assay buffer. The obtained PRL-antisera were characterized in terms of titer, immuno response and displacement profile. Formulation, optimization and validation of the local liquid phase RIA system were carried out. The results obtained provide a highly sensitive, specific and accurate RIA system of PRL. In conclusion, this technique could be used in diagnosis of pituitary dysfunction such as hyperprolactinaemia and hyperprolactinaemia, prolactinoma, galactorrhoea, amenorrhea and diagnosis of infertility in males and females.

  10. Ammonium removal from aqueous solutions by clinoptilolite: determination of isotherm and thermodynamic parameters and comparison of kinetics by the double exponential model and conventional kinetic models.

    Science.gov (United States)

    Tosun, Ismail

    2012-03-01

    The adsorption isotherm, the adsorption kinetics, and the thermodynamic parameters of ammonium removal from aqueous solution by using clinoptilolite in aqueous solution was investigated in this study. Experimental data obtained from batch equilibrium tests have been analyzed by four two-parameter (Freundlich, Langmuir, Tempkin and Dubinin-Radushkevich (D-R)) and four three-parameter (Redlich-Peterson (R-P), Sips, Toth and Khan) isotherm models. D-R and R-P isotherms were the models that best fitted to experimental data over the other two- and three-parameter models applied. The adsorption energy (E) from the D-R isotherm was found to be approximately 7 kJ/mol for the ammonium-clinoptilolite system, thereby indicating that ammonium is adsorbed on clinoptilolite by physisorption. Kinetic parameters were determined by analyzing the nth-order kinetic model, the modified second-order model and the double exponential model, and each model resulted in a coefficient of determination (R(2)) of above 0.989 with an average relative error lower than 5%. A Double Exponential Model (DEM) showed that the adsorption process develops in two stages as rapid and slow phase. Changes in standard free energy (∆G°), enthalpy (∆H°) and entropy (∆S°) of ammonium-clinoptilolite system were estimated by using the thermodynamic equilibrium coefficients.

  11. Ammonium Removal from Aqueous Solutions by Clinoptilolite: Determination of Isotherm and Thermodynamic Parameters and Comparison of Kinetics by the Double Exponential Model and Conventional Kinetic Models

    Directory of Open Access Journals (Sweden)

    İsmail Tosun

    2012-03-01

    Full Text Available The adsorption isotherm, the adsorption kinetics, and the thermodynamic parameters of ammonium removal from aqueous solution by using clinoptilolite in aqueous solution was investigated in this study. Experimental data obtained from batch equilibrium tests have been analyzed by four two-parameter (Freundlich, Langmuir, Tempkin and Dubinin-Radushkevich (D-R and four three-parameter (Redlich-Peterson (R-P, Sips, Toth and Khan isotherm models. D-R and R-P isotherms were the models that best fitted to experimental data over the other two- and three-parameter models applied. The adsorption energy (E from the D-R isotherm was found to be approximately 7 kJ/mol for the ammonium-clinoptilolite system, thereby indicating that ammonium is adsorbed on clinoptilolite by physisorption. Kinetic parameters were determined by analyzing the nth-order kinetic model, the modified second-order model and the double exponential model, and each model resulted in a coefficient of determination (R2 of above 0.989 with an average relative error lower than 5%. A Double Exponential Model (DEM showed that the adsorption process develops in two stages as rapid and slow phase. Changes in standard free energy (∆G°, enthalpy (∆H° and entropy (∆S° of ammonium-clinoptilolite system were estimated by using the thermodynamic equilibrium coefficients.

  12. Negative chemical ionization GC/MS determination of nitrite and nitrate in seawater using exact matching double spike isotope dilution and derivatization with triethyloxonium tetrafluoroborate.

    Science.gov (United States)

    Pagliano, Enea; Meija, Juris; Sturgeon, Ralph E; Mester, Zoltan; D'Ulivo, Alessandro

    2012-03-06

    The alkylation of nitrite and nitrate by triethyloxonium tetrafluoroborate allows determination of their ethyl esters by headspace gas chromatography/mass spectrometry (GC/MS). In the present study, significant improvement in analytical performance is achieved using negative chemical ionization providing detection limits of 150 ng/L for NO(2)(-) and 600 ng/L for NO(3)(-), an order of magnitude better than those achieved using electron impact ionization. The derivatization procedure was optimized and alkaline conditions adopted to minimize conversion of nitrite to nitrate (determined to be 0.07% at 100 mg/L NO(2)(-)) and to avoid the exchange of oxygen between the analytes and the solvent (water). Quantitation entails use of isotopically enriched standards (N(18)O(2)(-) and (15)NO(3)(-)), which also permits monitoring of potential conversion from nitrite to nitrate during the analysis (double spike isotope dilution).

  13. Accidental degeneracy of resonances

    International Nuclear Information System (INIS)

    Hernandez, E.; Mondragon, A.; Jauregui, A.

    2001-01-01

    Full text: It will be shown that a degeneracy of resonances is associated with a second rank pole in the scattering matrix and a Jordan cycle of generalized eigenfunctions of the radial Schrodinger equation. The generalized Gamow-Jordan eigenfunctions are basis elements of an expansion in complex resonance energy eigenfunctions. In this orthonormal basis, the Hamiltonian is represented by a non-diagonal complex matrix with a Jordan block of rank two. Some general properties of the degeneracy of resonances will be exhibited and discussed in an explicit example of degeneracy of resonant states and double poles in the scattering matrix of a double barrier potential. The cross section, scattering wave functions and Jordan-Gamow eigenfunctions are computed at degeneracy and their properties as functions of the control parameters of the system are discussed. (Author)

  14. Double isotope method for the determination of catecholamines, serotonin, and other amines in the picomole range as their dansyl derivatives

    International Nuclear Information System (INIS)

    Recasens, M.; Zwiller, J.; Mack, G.; Zanetta, J.P.; Mandel, P.

    1977-01-01

    A method based on thin-layer chromatographic separation of radioactive products is described for the determination and the quantification of dopamine (DA), noradrenaline (NA), adrenaline (A), normetanephrine (NMN), and serotonin (5HT) in small samples of brain tissue. In this method the amines are converted to [ 14 C]dansyl derivatives by reaction with [ 14 C]dansyl chloride [ 14 C]Dans-Cl) and 3 H-labeled amines are used as internal standards to determine variations in yield

  15. Accurate distance determination of nucleic acids via Förster resonance energy transfer: implications of dye linker length and rigidity.

    Science.gov (United States)

    Sindbert, Simon; Kalinin, Stanislav; Nguyen, Hien; Kienzler, Andrea; Clima, Lilia; Bannwarth, Willi; Appel, Bettina; Müller, Sabine; Seidel, Claus A M

    2011-03-02

    In Förster resonance energy transfer (FRET) experiments, the donor (D) and acceptor (A) fluorophores are usually attached to the macromolecule of interest via long flexible linkers of up to 15 Å in length. This causes significant uncertainties in quantitative distance measurements and prevents experiments with short distances between the attachment points of the dyes due to possible dye-dye interactions. We present two approaches to overcome the above problems as demonstrated by FRET measurements for a series of dsDNA and dsRNA internally labeled with Alexa488 and Cy5 as D and A dye, respectively. First, we characterize the influence of linker length and flexibility on FRET for different dye linker types (long, intermediate, short) by analyzing fluorescence lifetime and anisotropy decays. For long linkers, we describe a straightforward procedure that allows for very high accuracy of FRET-based structure determination through proper consideration of the position distribution of the dye and of linker dynamics. The position distribution can be quickly calculated with geometric accessible volume (AV) simulations, provided that the local structure of RNA or DNA in the proximity of the dye is known and that the dye diffuses freely in the sterically allowed space. The AV approach provides results similar to molecular dynamics simulations (MD) and is fully consistent with experimental FRET data. In a benchmark study for ds A-RNA, an rmsd value of 1.3 Å is achieved. Considering the case of undefined dye environments or very short DA distances, we introduce short linkers with a propargyl or alkenyl unit for internal labeling of nucleic acids to minimize position uncertainties. Studies by ensemble time correlated single photon counting and single-molecule detection show that the nature of the linker strongly affects the radius of the dye's accessible volume (6-16 Å). For short propargyl linkers, heterogeneous dye environments are observed on the millisecond time scale. A

  16. A Prospective Study of the Utility of Magnetic Resonance Imaging in Determining Candidacy for Partial Breast Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Dorn, Paige L.; Al-Hallaq, Hania A.; Haq, Farah; Goldberg, Mira [Department of Radiation and Cellular Oncology, University of Chicago Medical Center, Chicago, Illinois (United States); Abe, Hiroyuki [Department of Radiology, University of Chicago Medical Center, Chicago, Illinois (United States); Hasan, Yasmin [Department of Radiation and Cellular Oncology, University of Chicago Medical Center, Chicago, Illinois (United States); Chmura, Steven J., E-mail: schmura@radonc.uchicago.edu [Department of Radiation and Cellular Oncology, University of Chicago Medical Center, Chicago, Illinois (United States)

    2013-03-01

    Purpose: Retrospective data have demonstrated that breast magnetic resonance imaging (MRI) may change a patient's eligibility for partial breast irradiation (PBI) by identifying multicentric, multifocal, or contralateral disease. The objective of the current study was to prospectively determine the frequency with which MRI identifies occult disease and to establish clinical factors associated with a higher likelihood of MRI prompting changes in PBI eligibility. Methods and Materials: At The University of Chicago, women with breast cancer uniformly undergo MRI in addition to mammography and ultrasonography. From June 2009 through May 2011, all patients were screened prospectively in a multidisciplinary conference for PBI eligibility based on standard imaging, and the impact of MRI on PBI eligibility according to National Surgical Adjuvant Breast and Bowel Project protocol B-39/Radiation Therapy Oncology Group protocol 0413 entry criteria was recorded. Univariable analysis was performed using clinical characteristics in both the prospective cohort and in a separate cohort of retrospectively identified patients. Pooled analysis was used to derive a scoring index predictive of the risk that MRI would identify additional disease. Results: A total of 521 patients were screened for PBI eligibility, and 124 (23.8%) patients were deemed eligible for PBI based on standard imaging. MRI findings changed PBI eligibility in 12.9% of patients. In the pooled univariable analysis, tumor size ≥2 cm on mammography or ultrasonography (P=.02), age <50 years (P=.01), invasive lobular histology (P=.01), and HER-2/neu amplification (P=.01) were associated with a higher likelihood of MRI changing PBI eligibility. A predictive score was generated by summing the number of significant risk factors. Patients with a score of 0, 1, 2, and 3 had changes to eligibility based on MRI findings in 2.8%, 13.2%, 38.1%, and 100%, respectively (P<.0001). Conclusions: MRI identified additional

  17. Magnetic resonance imaging determined visceral fat reduction associates with enhanced IL-10 plasma levels in calorie restricted obese subjects.

    Directory of Open Access Journals (Sweden)

    Gloria Formoso

    Full Text Available BACKGROUND: Obesity is characterized by a low grade chronic inflammation state. Indeed circulating pro-inflammatory cytokines, such as TNF-α and IL-6, are elevated in obese subjects, while anti-inflammatory cytokines, such as IL-10, appear to be reduced. Cytokines profile improves after weight loss, but how visceral or subcutaneous fat loss respectively affect pro- or anti-inflammatory cytokines plasma levels has not been precisely assessed. Therefore in the present study we correlated changes in circulating cytokine profile with quantitative changes in visceral and subcutaneous adipose tissue depots measured by an ad hoc Magnetic Resonance Imaging (MRI protocol before and after weight loss. MATERIALS AND METHODS: In 14 obese subjects, MRI determination of visceral and subcutaneous fat and plasma glucose, insulin, TNF-α IL-6, and IL-10 measurements were performed before and after a caloric restriction induced weight loss of at least 5% of the original body weight. RESULTS: Weight loss improved insulin sensitivity (QUICKI Index: 0.35±0.03 vs 0.37±0.04; P<0.05, increased IL-10 (3.4±1.9 vs 4.6±1.0 pg/mL; P<0.03, and reduced TNF-α and IL-6 plasma levels (2.5±1.3 vs 1.6±1.5 pg/mL, P<0.0015, 2.3±0.4 vs 1.6±0.6 pg/mL, P<0.02 respectively. A significant correlation was observed between the amount of visceral fat loss and the percentage reduction in both TNF-α (r = 0.56, p<0.05 and IL-6 (r = 0.19 p<0.05 plasma levels. In a multiple regression analysis, the amount of visceral fat loss independently correlated with the increase in IL-10 plasma levels. CONCLUSION: The reduction in visceral adipose tissue is the main driver of the improved inflammatory profile induced by weight loss.

  18. Efficacy of double inversion recovery magnetic resonance imaging for the evaluation of the synovium in the femoro-patellar joint without contrast enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Son, Ye Na; Jin, Wook; Jahng, Geon-Ho; Park, Yong Sung; Park, So Young [Kyung Hee University School of Medicine, Department of Radiology, Kyung Hee University Hospital at Gangdong, Seoul (Korea, Republic of); Cha, Jang Gyu [Soonchunhyang University Bucheon Hospital, Department of Radiology, Bucheon-si, Gyeonggi-do (Korea, Republic of); Yun, Seong Jong [Kyung Hee University School of Medicine, Department of Radiology, Kyung Hee University Hospital at Gangdong, Seoul (Korea, Republic of); Department of Radiology, Aerospace Medical Center, Republic of Korea Air Force, Cheongwon-gun, Chungcheongbuk-do (Korea, Republic of); Park, Ji Seon; Ryu, Kyung Nam [Kyung Hee University Hospital, Department of Radiology, Seoul (Korea, Republic of)

    2018-02-15

    To investigate the efficacy of double inversion recovery (DIR) sequence for evaluating the synovium of the femoro-patellar joint without contrast enhancement (CE). Two radiologists independently evaluated the axial DIR and CE T1-weighted fat-saturated (CET1FS) images of 33 knees for agreement; the visualisation and distribution of the synovium were evaluated using a four-point visual scaling system at each of the five levels of the femoro-patellar joint and the location of the thickest synovium. The maximal synovial thickness at each sequence was measured by consensus. The interobserver agreement was good (κ = 0.736) for the four-point scale, and was excellent for the location of the thickest synovium on DIR and CET1FS (κ = 0.955 and 0.954). The intersequential agreement for the area with the thickest synovium was also excellent (κ = 0.845 and κ = 0.828). The synovial thickness on each sequence showed excellent correlation (r = 0.872). The DIR showed as good a correlation as CET1FS for the evaluation of the synovium at the femoro-patellar joint. DIR may be a useful MR technique for evaluating the synovium without CE. (orig.)

  19. High-precision determination of the isotopic composition of dissolved iron in iron depleted seawater by double spike multicollector-ICPMS.

    Science.gov (United States)

    Lacan, Francois; Radic, Amandine; Labatut, Marie; Jeandel, Catherine; Poitrasson, Franck; Sarthou, Geraldine; Pradoux, Catherine; Chmeleff, Jerome; Freydier, Remi

    2010-09-01

    This work demonstrates the feasibility of the measurement of the isotopic composition of dissolved iron in seawater for an iron concentration range, 0.05-1 nmol L(-1), allowing measurements in most oceanic waters, including Fe depleted waters of high nutrient low chlorophyll areas. It presents a detailed description of our previously published protocol, with significant improvements on detection limit and blank contribution. Iron is preconcentrated using a nitriloacetic acid superflow resin and purified using an AG 1-x4 anion exchange resin. The isotopic ratios are measured with a multicollector-inductively coupled plasma mass spectrometer (MC-ICPMS) Neptune, coupled with a desolvator (Aridus II or Apex-Q), using a (57)Fe-(58)Fe double spike mass bias correction. A Monte Carlo test shows that optimum precision is obtained for a double spike composed of approximately 50% (57)Fe and 50% (58)Fe and a sample to double spike quantity ratio of approximately 1. Total procedural yield is 91 +/- 25% (2SD, n = 55) for sample sizes from 20 to 2 L. The procedural blank ranges from 1.4 to 1.1 ng, for sample sizes ranging from 20 to 2 L, respectively, which, converted into Fe concentrations, corresponds to blank contributions of 0.001 and 0.010 nmol L(-1), respectively. Measurement precision determined from replicate measurements of seawater samples and standard solutions is 0.08 per thousand (delta(56)Fe, 2SD). The precision is sufficient to clearly detect and quantify isotopic variations in the oceans, which so far have been observed to span 2.5 per thousand and thus opens new perspectives to elucidate the oceanic iron cycle.

  20. High-efficiency ytterbium-free erbium-doped all-glass double cladding silicate glass fiber for resonantly-pumped fiber lasers.

    Science.gov (United States)

    Qiang, Zexuan; Geng, Jihong; Luo, Tao; Zhang, Jun; Jiang, Shibin

    2014-02-01

    A highly efficient ytterbium-free erbium-doped silicate glass fiber has been developed for high-power fiber laser applications at an eye-safe wavelength near 1.55 μm. Our preliminary experiments show that high laser efficiency can be obtained from a relatively short length of the gain fiber when resonantly pumped at 1535 nm in both core- and cladding-pumping configurations. With a core-pumping configuration as high as 75%, optical-to-optical efficiency and 4 W output power were obtained at 1560 nm from a 1 m long gain fiber. When using a cladding-pumping configuration, approximately 13 W output power with 67.7% slope efficiency was demonstrated from a piece of 2 m long fiber. The lengths of silicate-based gain fiber are much shorter than their silica-based counterparts used in other experiments, which is significantly important for high-power narrow-band and/or pulsed laser applications.

  1. Effects of chondroitin sulfate on brain response to painful stimulation in knee osteoarthritis patients. A randomized, double-blind, placebo-controlled functional magnetic resonance imaging study.

    Science.gov (United States)

    Monfort, Jordi; Pujol, Jesús; Contreras-Rodríguez, Oren; Llorente-Onaindia, Jone; López-Solà, Marina; Blanco-Hinojo, Laura; Vergés, Josep; Herrero, Marta; Sánchez, Laura; Ortiz, Hector; Montañés, Francisco; Deus, Joan; Benito, Pere

    2017-06-21

    Knee osteoarthritis is causing pain and functional disability. One of the inherent problems with efficacy assessment of pain medication was the lack of objective pain measurements, but functional magnetic resonance imaging (fMRI) has emerged as a useful means to objectify brain response to painful stimulation. We have investigated the effect of chondroitin sulfate (CS) on brain response to knee painful stimulation in patients with knee osteoarthritis using fMRI. Twenty-two patients received CS (800mg/day) and 27 patients placebo, and were assessed at baseline and after 4 months of treatment. Two fMRI tests were conducted in each session by applying painful pressure on the knee interline and on the patella surface. The outcome measurement was attenuation of the response evoked by knee painful stimulation in the brain. fMRI of patella pain showed significantly greater activation reduction under CS compared with placebo in the region of the mesencephalic periaquecductal gray. The CS group, additionally showed pre/post-treatment activation reduction in the cortical representation of the leg. No effects of CS were detected using the interline pressure test. fMRI was sensitive to objectify CS effects on brain response to painful pressure on patellofemoral cartilage, which is consistent with the known CS action on chondrocyte regeneration. The current work yields further support to the utility of fMRI to objectify treatment effects on osteoarthritis pain. Copyright © 2017 Elsevier España, S.L.U. All rights reserved.

  2. Experimental determination of the interference contributions RLT and RTT to the cross section of the charged-pion electroproduction in the Δ+(1232) resonance region

    International Nuclear Information System (INIS)

    Brunhoeber, H.

    2001-11-01

    The interference terms R LT and R TT that contribute to the cross section of the charged pion electroproduction have been determined in an electron scattering experiment at the accelerator facility ELSA by detecting the outgoing neutron of the nπ + -decay channel by a large acceptance Time-of-Flight spectrometer covering the Δ + (1232) resonance region at the four momentum transfers of 0.638 GeV 2 and 0.8 GeV 2 . (orig.)

  3. Two-Dimensional Nuclear Magnetic Resonance Structure Determination Module for Introductory Biochemistry: Synthesis and Structural Characterization of Lyso-Glycerophospholipids

    Science.gov (United States)

    Garrett, Teresa A.; Rose, Rebecca L.; Bell, Sidney M.

    2013-01-01

    In this laboratory module, introductory biochemistry students are exposed to two-dimensional [superscript 1]H-nuclear magnetic resonance of glycerophospholipids (GPLs). Working in groups of three, students enzymatically synthesized and purified a variety of 2-acyl lyso GPLs. The structure of the 2-acyl lyso GPL was verified using [superscript…

  4. Determination of diffuse double layer protonation constants for hydrous ferric oxide (HFO): supporting evidence for the Dzombak and Morel compilation

    CSIR Research Space (South Africa)

    Pretorius, PJ

    1998-01-01

    Full Text Available of the experimental system suggests that titration points below pH 4 should not be used for the determination of protonation constants because of potential HFO dissolution. Surface protonation constant, PZC and binding site estimates agree excellently with currently...

  5. A Magnetic Resonance Spectroscopy Study of Lovastatin for Treating Bipolar Mood Disorder: A 4-Week Randomized Double-Blind, Placebo- Controlled Clinical Trial.

    Science.gov (United States)

    Lotfi, Mehrzad; Shafiee, Sara; Ghanizadeh, Ahmd; Sigaroudi, Motahar O; Razeghian, Leila

    2017-01-01

    No trial has examined the effect of lovastatin on the brain metabolites in patients with bipolar mood disorder. Current medications for treating bipolar disorders cause metabolic syndrome. It is supposed that lovastatin not only decreases the rate of metabolic syndrome but also impacts some brain metabolites and their ratio like common treatments that are measured by Magnetic Resonance Spectroscopy. 27 Manic phase patients were randomly allocated into two groups, lovastatin and placebo as their adjuant medication. Clinical symptoms were assessed at baseline, weeks 2, 4. The brain metabolites were measured at baseline and week 4. Regarding the change of clinical symptoms, no significant difference was found between two groups. However, lovastatin significantly increased the level of NAA in cingulate gyrus in comparison to the placebo group. Moreover, lovastatin more than placebo increased creatine in the left basal ganglia. Furthermore, choline/ creatine showed a significant decrease in the left basal ganglia in lovastatin group. Using MRS after treating with lovastatin showed lovastatin increases NAA in cingulate gyrus, indicating the possible effect of NAA for increasing the reduced viable neuron. Moreover, the increment of Cr by lovastatin in the left basal ganglia suggests the role of lovastatin for maintaining energy homeostasis, anti-apoptotic activity and ATP production in bipolar disorder. Some patents using lovastatin as an adjuant therapy for treating bipolar patients and depression in MDD patients are also outlined. This trial was registered in the Iranian Clinical Trials Registry (http://www.irct.ir/) (IRCT201302203930N18). Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  6. Effect of DA-9701 on Gastric Motor Function Assessed by Magnetic Resonance Imaging in Healthy Volunteers: A Randomized, Double-Blind, Placebo-Controlled Trial.

    Science.gov (United States)

    Min, Yang Won; Min, Byung-Hoon; Kim, Seonwoo; Choi, Dongil; Rhee, Poong-Lyul

    2015-01-01

    Improving gastric accommodation and gastric emptying is an attractive physiological treatment target in patients with functional dyspepsia (FD). We evaluated the effect of DA-9701, a new drug for FD, on gastric motor function after a meal in healthy volunteers using magnetic resonance imaging (MRI). Forty healthy volunteers were randomly allocated to receive either DA-9701 or placebo. After 5 days of treatment, subjects underwent gastric MRI (60 min before and 15, 30, 45, 60, 90, and 120 min after a liquid test meal). Gastric volume was measured through 3-dimensional reconstruction from MRI data. We analyzed 4 outcome variables including changes in total gastric volume (TGV), proximal TGV, and proximal to distal TGV ratio after a meal and gastric emptying rates after adjusting values at the pre-test meal. Changes in TGV and proximal TGV after a meal did not differ between the DA-9701 and placebo groups (difference between groups -25.9 mL, 95% confidence interval [CI] -54.0 to 2.3 mL, P = 0.070 and -2.9 mL, 95% CI -30.3 to 24.5 mL, P = 0.832, respectively). However, pre-treatment with DA-9701 increased postprandial proximal to distal TGV ratio more than placebo (difference between groups 0.93, 95% CI 0.08 to 1.79, P = 0.034). In addition, pre-treatment with DA-9701 significantly increased gastric emptying as compared with placebo (mean difference between groups 3.41%, 95% CI 0.54% to 6.29%, P = 0.021, by mixed model for repeated measures). Our results suggested that DA-9701 enhances gastric emptying and does not significantly affect gastric accommodation in healthy volunteers. Further studies to confirm whether DA-9701 enhances these gastric motor functions in patients with FD are warranted. ClinicalTrials.gov NCT02091635.

  7. Effect of DA-9701 on Gastric Motor Function Assessed by Magnetic Resonance Imaging in Healthy Volunteers: A Randomized, Double-Blind, Placebo-Controlled Trial.

    Directory of Open Access Journals (Sweden)

    Yang Won Min

    Full Text Available Improving gastric accommodation and gastric emptying is an attractive physiological treatment target in patients with functional dyspepsia (FD. We evaluated the effect of DA-9701, a new drug for FD, on gastric motor function after a meal in healthy volunteers using magnetic resonance imaging (MRI.Forty healthy volunteers were randomly allocated to receive either DA-9701 or placebo. After 5 days of treatment, subjects underwent gastric MRI (60 min before and 15, 30, 45, 60, 90, and 120 min after a liquid test meal. Gastric volume was measured through 3-dimensional reconstruction from MRI data. We analyzed 4 outcome variables including changes in total gastric volume (TGV, proximal TGV, and proximal to distal TGV ratio after a meal and gastric emptying rates after adjusting values at the pre-test meal.Changes in TGV and proximal TGV after a meal did not differ between the DA-9701 and placebo groups (difference between groups -25.9 mL, 95% confidence interval [CI] -54.0 to 2.3 mL, P = 0.070 and -2.9 mL, 95% CI -30.3 to 24.5 mL, P = 0.832, respectively. However, pre-treatment with DA-9701 increased postprandial proximal to distal TGV ratio more than placebo (difference between groups 0.93, 95% CI 0.08 to 1.79, P = 0.034. In addition, pre-treatment with DA-9701 significantly increased gastric emptying as compared with placebo (mean difference between groups 3.41%, 95% CI 0.54% to 6.29%, P = 0.021, by mixed model for repeated measures.Our results suggested that DA-9701 enhances gastric emptying and does not significantly affect gastric accommodation in healthy volunteers. Further studies to confirm whether DA-9701 enhances these gastric motor functions in patients with FD are warranted.ClinicalTrials.gov NCT02091635.

  8. Double resonance spectroscopy of the D1Πu+ and B′′ B-bar 1Σu+ states near the third dissociation threshold of H2

    International Nuclear Information System (INIS)

    Ekey, R C; Cordova, A E; Duan, W; Chartrand, A M; McCormack, E F

    2013-01-01

    Double-resonance laser spectroscopy via the E,F 1 Σ g + ,v ′ =6,J ′ state was used to probe the energy region below the third dissociation limit of molecular hydrogen. Resonantly enhanced multi-photon ionization spectra were recorded by detecting ion production as a function of energy using a time-of-flight mass spectrometer. Energies and line widths for the v = 14–17 levels of the D 1 Π u + state of H 2 are reported and compared to experimental data obtained by using VUV synchrotron light excitation (Dickenson et al 2010 J. Chem. Phys. 133 144317) and fully ab initio non-adiabatic calculations of D 1 Π u + state energies and line widths (Glass-Maujean et al 2012 Phys. Rev. A 86 052507). Several high vibrational levels of the B ′′ B-bar 1 Σ u + state were also observed in this region. Term energies and rotational constants for the v = 67–69 vibrational levels are reported and compared to highly accurate ro-vibrational energy level predictions from fully ab initio non-adiabatic calculations of the first six 1 Σ u + levels of H 2 (Wolniewicz et al 2006 J. Mol. Spectrosc. 238 118). While additional observed transitions can be assigned to other states, several unassigned features in the spectra highlight the need for a fully integrated theoretical treatment of dissociation and ionization to understand the complex pattern of highly vibrationally excited states expected in this region. (paper)

  9. Double-double effect and coordination number

    International Nuclear Information System (INIS)

    Mioduski, T.

    1992-01-01

    The original method of interpretation together with its theoretical foundations is developed, making it possible to use location and direction of the double-double (tetrad) effect within the Ln and An series to determine the coordination number (CN) complexes of the f-block elements. The method is applied for potentiometric and radiometric equilibrium studies. It has been pointed and that the decisive factor for the direction of the double-double effect in the case of the Gibbs energy variations is a difference in the CN of the f-element ion between the reaction product complex and that for the reaction substrate the ''regular'' effect for a given tetrad is accompanied by decrease in the CN while the ''reverse'' effect by increase in the CN. (author). 122 refs, 5 tabs, 8 figs

  10. Observing Double Stars

    Science.gov (United States)

    Genet, Russell M.; Fulton, B. J.; Bianco, Federica B.; Martinez, John; Baxter, John; Brewer, Mark; Carro, Joseph; Collins, Sarah; Estrada, Chris; Johnson, Jolyon; Salam, Akash; Wallen, Vera; Warren, Naomi; Smith, Thomas C.; Armstrong, James D.; McGaughey, Steve; Pye, John; Mohanan, Kakkala; Church, Rebecca

    2012-05-01

    Double stars have been systematically observed since William Herschel initiated his program in 1779. In 1803 he reported that, to his surprise, many of the systems he had been observing for a quarter century were gravitationally bound binary stars. In 1830 the first binary orbital solution was obtained, leading eventually to the determination of stellar masses. Double star observations have been a prolific field, with observations and discoveries - often made by students and amateurs - routinely published in a number of specialized journals such as the Journal of Double Star Observations. All published double star observations from Herschel's to the present have been incorporated in the Washington Double Star Catalog. In addition to reviewing the history of visual double stars, we discuss four observational technologies and illustrate these with our own observational results from both California and Hawaii on telescopes ranging from small SCTs to the 2-meter Faulkes Telescope North on Haleakala. Two of these technologies are visual observations aimed primarily at published "hands-on" student science education, and CCD observations of both bright and very faint doubles. The other two are recent technologies that have launched a double star renaissance. These are lucky imaging and speckle interferometry, both of which can use electron-multiplying CCD cameras to allow short (30 ms or less) exposures that are read out at high speed with very low noise. Analysis of thousands of high speed exposures allows normal seeing limitations to be overcome so very close doubles can be accurately measured.

  11. Comparison of triple to double coincidence ratio and Quench Parameter External methods for the determination of 3H efficiency by liquid scintillation counting

    International Nuclear Information System (INIS)

    Nisti, M.B.; Saueia, C.H.R.; Mazzilli, B.P.

    2013-01-01

    The aim of this study is to determine the tritium efficiency by liquid scintillation counting using two methodologies, Quench Parameter External (QPE) and Triple to Double Coincidence Ratio (TDCR), and to compare the results. The equipment used was the HIDEX model 300-SL Liquid Scintillation Counter, composed of three photomultipliers coupled with coincidence pulses, discrimination level and Mikro Win 2000 software. The efficiency varied from 0.028 to 0.706 cps dps -1 for QPE and from 0.061 to 0.703 cps dps -1 for TDCR. Different efficiencies were obtained using both methods, in the range from 459 to 572 quenching, above this range the efficiencies were similar. The verification of the efficiencies was performed by participating in the Intercomparison National Program (PNI). (author)

  12. Properties of spiral resonators

    International Nuclear Information System (INIS)

    Haeuser, J.

    1989-10-01

    The present thesis deals with the calculation and the study of the application possibilities of single and double spiral resonators. The main aim was the development and the construction of reliable and effective high-power spiral resonators for the UNILAC of the GSI in Darmstadt and the H - -injector for the storage ring HERA of DESY in Hamburg. After the presentation of the construction and the properties of spiral resonators and their description by oscillating-circuit models the theoretical foundations of the bunching are presented and some examples of a rebuncher and debuncher and their influence on the longitudinal particle dynamics are shown. After the description of the characteristic accelerator quantities by means of an oscillating-circuit model and the theory of an inhomogeneous λ/4 line it is shown, how the resonance frequency and the efficiency of single and double spiral resonators can be calculated from the geometrical quantities of the structure. In the following the dependence of the maximal reachable resonator voltage in dependence on the gap width and the surface of the drift tubes is studied. Furthermore the high-power resonators are presented, which were built for the different applications for the GSI in Darmstadt, DESY in Hamburg, and for the FOM Institute in Amsterdam. (orig./HSI) [de

  13. Determination of effective resonance energies for the (n,γ) reactions of 152Sm and 165Ho by using dual monitors

    International Nuclear Information System (INIS)

    Budak, M.G.; Karadag, M.; Yuecel, H.

    2010-01-01

    The effective resonance energies E - bar r for the (n,γ) reactions of 152 Sm and 165 Ho isotopes were determined by using dual monitors ( 55 Mn- 98 Mo) due to their favourable resonance properties. The samples were irradiated in an isotropic neutron field obtained from 241 Am-Be neutron sources. The induced activities were measured with a high efficient, p-type Ge detector. The necessary correction factors for thermal neutron self-shielding (G th ), resonance neutron self-shielding (G epi ), self absorption (F s ) and true coincidence summing (F coi ) effects for the measured γ-rays were taken into account. Thus, the experimental E - bar r -values for above (n,γ) reactions are found to be 8.65 ± 1.80 eV for 152 Sm and 12.90 ± 2.69 eV for 165 Ho isotopes, respectively. The E - bar r -values for both 152 Sm and 165 Ho isotopes were also theoretically calculated from the newest resonance data in the literature. Theoretically calculated E - bar r -values are estimated to be 8.34 eV and 8.53 eV for 152 Sm by two different approaches, which are generally, much smaller than that the present experimental value by 1.4-3.6% for 152 Sm. In case of 165 Ho isotope, the theoretically calculated E - bar r -value of 8.63 eV from the first approach deviates substantially from the measured value by about 33%, whereas the theoretical E - bar r -value of 12.95 eV from the second approach agrees very well with our experimentally determined E - bar r -value. The results show that the present experimental E - bar r -values for 152 Sm and 165 Ho isotopes agree with the calculated ones from the second approach within limits of the estimated uncertainty if the recently evaluated resonance data are used. However, it is worth noting that the results for E - bar r -value calculated from the first approach are not satisfactorily accurate because of neglecting the neutron widths in that approach. Therefore, this study implies that it be regarded to the experimentally determined E - bar r

  14. Atomic gas temperature in a nonequilibrium high-intensity discharge lamp determined from the red wing of the resonance mercury line 254 nm

    International Nuclear Information System (INIS)

    Drakakis, E.; Karabourniotis, D.

    2012-01-01

    For developing low-wattage high intensity discharge (HID) lamps, a better understanding of the relatively unexplored nonequilibrium phenomena is essential. This needs interpretation of diagnostic results by methods free from equilibrium assumptions. In this paper, the atomic temperature is determined from the simulation of a quasistatic broadened resonance line by distinguishing between atomic temperature and excitation temperature in the equation of radiative transfer. The proposed method is applied to the red wing of the resonance mercury line 254 nm emitted from a HID lamp working on ac. The experimental results show severe deviation from local thermodynamic equilibrium. More than one thousand degrees difference was obtained between atomic and electron temperatures at the maximum current phase.

  15. Atomic gas temperature in a nonequilibrium high-intensity discharge lamp determined from the red wing of the resonance mercury line 254 nm

    Energy Technology Data Exchange (ETDEWEB)

    Drakakis, E. [Technological Educational Institute, Department of Electrical Engineering, 71004 Heraklion (Greece); Karabourniotis, D. [Institute of Plasma Physics, Department of Physics, University of Crete, 71003 Heraklion (Greece)

    2012-09-01

    For developing low-wattage high intensity discharge (HID) lamps, a better understanding of the relatively unexplored nonequilibrium phenomena is essential. This needs interpretation of diagnostic results by methods free from equilibrium assumptions. In this paper, the atomic temperature is determined from the simulation of a quasistatic broadened resonance line by distinguishing between atomic temperature and excitation temperature in the equation of radiative transfer. The proposed method is applied to the red wing of the resonance mercury line 254 nm emitted from a HID lamp working on ac. The experimental results show severe deviation from local thermodynamic equilibrium. More than one thousand degrees difference was obtained between atomic and electron temperatures at the maximum current phase.

  16. Measurement of target and double-spin asymmetries for the e ⃗p ⃗→e π+(n ) reaction in the nucleon resonance region at low Q2

    Science.gov (United States)

    Zheng, X.; Adhikari, K. P.; Bosted, P.; Deur, A.; Drozdov, V.; El Fassi, L.; Kang, Hyekoo; Kovacs, K.; Kuhn, S.; Long, E.; Phillips, S. K.; Ripani, M.; Slifer, K.; Smith, L. C.; Adikaram, D.; Akbar, Z.; Amaryan, M. J.; Anefalos Pereira, S.; Asryan, G.; Avakian, H.; Badui, R. A.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A. S.; Briscoe, W. J.; Bültmann, S.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Chen, J.-P.; Chetry, T.; Choi, Seonho; Ciullo, G.; Clark, L.; Colaneri, L.; Cole, P. L.; Compton, N.; Contalbrigo, M.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Djalali, C.; Dodge, G. E.; Dupre, R.; Egiyan, H.; El Alaoui, A.; Elouadrhiri, L.; Eugenio, P.; Fanchini, E.; Fedotov, G.; Fersch, R.; Filippi, A.; Fleming, J. A.; Gevorgyan, N.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Gleason, C.; Golovach, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Hanretty, C.; Harrison, N.; Hattawy, M.; Hicks, K.; Holtrop, M.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jenkins, D.; Jiang, H.; Jo, H. S.; Joosten, S.; Keller, D.; Khachatryan, G.; Khandaker, M.; Kim, A.; Kim, W.; Klein, F. J.; Kubarovsky, V.; Lanza, L.; Lenisa, P.; Livingston, K.; MacGregor, I. J. D.; Markov, N.; McKinnon, B.; Mirazita, M.; Mokeev, V.; Movsisyan, A.; Munevar, E.; Munoz Camacho, C.; Murdoch, G.; Nadel-Turonski, P.; Net, L. A.; Ni, A.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Paolone, M.; Paremuzyan, R.; Park, K.; Pasyuk, E.; Peng, P.; Pisano, S.; Pogorelko, O.; Price, J. W.; Puckett, A. J. R.; Raue, B. A.; Rizzo, A.; Rosner, G.; Rossi, P.; Roy, P.; Sabatié, F.; Salgado, C.; Schumacher, R. A.; Sharabian, Y. G.; Skorodumina, Iu.; Smith, G. D.; Sokhan, D.; Sparveris, N.; Stankovic, I.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tian, Ye; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Wei, X.; Weinstein, L. B.; Wood, M. H.; Zachariou, N.; Zhang, J.; Zonta, I.; CLAS Collaboration

    2016-10-01

    We report measurements of target- and double-spin asymmetries for the exclusive channel e ⃗p ⃗→e π+(n ) in the nucleon resonance region at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). These asymmetries were extracted from data obtained using a longitudinally polarized NH3 target and a longitudinally polarized electron beam with energies 1.1, 1.3, 2.0, 2.3, and 3.0 GeV. The new results are consistent with previous CLAS publications but are extended to a low Q2 range from 0.0065 to 0.35 (GeV/c ) 2 . The Q2 access was made possible by a custom-built Cherenkov detector that allowed the detection of electrons for scattering angles as low as 6∘. These results are compared with the unitary isobar models JANR and MAID, the partial-wave analysis prediction from SAID, and the dynamic model DMT. In many kinematic regions our results, in particular results on the target asymmetry, help to constrain the polarization-dependent components of these models.

  17. Physics of optimal resonant tunneling

    NARCIS (Netherlands)

    Racec, P.N.; Stoica, T.; Popescu, C.; Lepsa, M.I.; Roer, van de T.G.

    1997-01-01

    The optimal resonant tunneling, or the complete tunneling transparence of a biased double-barrier resonant-tunneling (DBRT) structure, is discussed. It is shown that its physics does not rest on the departure from the constant potential within the barriers and well, due to the applied electric

  18. Liquid scintillators and liquefied rare gases for particle detectors. Background-determination in Double Chooz and scintillation properties of liquid argon

    International Nuclear Information System (INIS)

    Hofmann, Martin Alexander

    2012-01-01

    Evidence for physics beyond the well-established standard model of particle physics is found in the sector of neutrino physics, in particular in neutrino oscillations, and in experimental hints requiring the presence of Dark Matter. Neutrino oscillations demand the neutrinos to be massive and at least four additional parameters, three mixing angles and one phase, are introduced. A non-vanishing value for the third mixing angle, θ 13 , has only recently been found, amongst others by the reactor antineutrino disappearance experiment Double Chooz. This experiment detects anti ν e 's by means of the Inverse Beta Decay (IBD), which has a clear signature that can very effectively be discriminated from most of the background. However, some background still survives the selection cuts applied to the data, partly induced by radioactivity. In order to determine the amount of radioimpurities in the detector, germanium spectroscopy measurements and neutron activation analyses have been carried out for various parts of the Double Chooz far detector. A dedicated Monte-Carlo simulation was performed to obtain the singles event rate induced by the identified radioimpurities in the fiducial volume of Double Chooz. In the present thesis, parts from the outer detector systems, as well as components of the inner detector liquids were measured. In sum, a singles rate of less than 0.35 Hz above the antineutrino detection threshold of 0.7 MeV has been found. This is by far below the design goal of Double Chooz of ∝ 20 Hz. The analysis of bismuth-polonium (BiPo) coincidences in the first Double Chooz data allows to directly determine the number of decays from the U- and the Th-decay chain in the active detector parts. Assuming radioactive equilibrium, concentrations of (1.71±0.08).10 -14 (g)/(g) for uranium and (8.16±0.49).10 -14 (g)/(g) for thorium have been found, which are also well below the design goal of Double Chooz (2.10 -13 (g)/(g)). Both gamma spectroscopy measurements and

  19. Liquid scintillators and liquefied rare gases for particle detectors. Background-determination in Double Chooz and scintillation properties of liquid argon

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, Martin Alexander

    2012-11-27

    Evidence for physics beyond the well-established standard model of particle physics is found in the sector of neutrino physics, in particular in neutrino oscillations, and in experimental hints requiring the presence of Dark Matter. Neutrino oscillations demand the neutrinos to be massive and at least four additional parameters, three mixing angles and one phase, are introduced. A non-vanishing value for the third mixing angle, {theta}{sub 13}, has only recently been found, amongst others by the reactor antineutrino disappearance experiment Double Chooz. This experiment detects anti {nu}{sub e}'s by means of the Inverse Beta Decay (IBD), which has a clear signature that can very effectively be discriminated from most of the background. However, some background still survives the selection cuts applied to the data, partly induced by radioactivity. In order to determine the amount of radioimpurities in the detector, germanium spectroscopy measurements and neutron activation analyses have been carried out for various parts of the Double Chooz far detector. A dedicated Monte-Carlo simulation was performed to obtain the singles event rate induced by the identified radioimpurities in the fiducial volume of Double Chooz. In the present thesis, parts from the outer detector systems, as well as components of the inner detector liquids were measured. In sum, a singles rate of less than 0.35 Hz above the antineutrino detection threshold of 0.7 MeV has been found. This is by far below the design goal of Double Chooz of {proportional_to} 20 Hz. The analysis of bismuth-polonium (BiPo) coincidences in the first Double Chooz data allows to directly determine the number of decays from the U- and the Th-decay chain in the active detector parts. Assuming radioactive equilibrium, concentrations of (1.71{+-}0.08).10{sup -14}(g)/(g) for uranium and (8.16{+-}0.49).10{sup -14}(g)/(g) for thorium have been found, which are also well below the design goal of Double Chooz (2.10{sup -13

  20. Determination of organic compounds in nano-particles by laser breakdown and resonant ionization time-of-flight mass spectrometry

    International Nuclear Information System (INIS)

    Deguchi, Yoshihiro; Tanaka, Nobuyuki

    2005-01-01

    Laser breakdown and resonance ionization time-of-flight mass spectrometry (TOFMS) with a differential mobility analyzer (DMA) was developed and applied to detect compositions and organic substances in nano-particles. The laser breakdown TOFMS method is capable of reaching pptv sensitivity, which is generally much better than the normal LIBS techniques. The system was demonstrated to successfully detect signals in the mass range of 1 to 300 amu for 60 and 140 nm particles in diesel engine exhaust. The detected signals showed that the nano-particles contained both aromatic and chain hydrocarbons

  1. Determination of temperature dependence of piezoelectric coefficients matrix of lead zirconate titanate ceramics by quasi-static and resonance method

    International Nuclear Information System (INIS)

    Li Fei; Xu Zhuo; Wei Xiaoyong; Yao Xi

    2009-01-01

    The piezoelectric coefficients (d 33 , -d 31 , d 15 , g 33 , -g 31 , g 15 ) of soft and hard lead zirconate titanate ceramics were measured by the quasi-static and resonance methods, at temperatures from 20 to 300 0 C. The results showed that the piezoelectric coefficients d 33 , -d 31 and d 15 obtained by these two methods increased with increasing temperature for both hard and soft PZT ceramics, while the piezoelectric coefficients g 33 , -g 31 and g 15 decreased with increasing temperature for both hard and soft PZT ceramics. In this paper, the observed results were also discussed in terms of intrinsic and extrinsic contributions to piezoelectric response.

  2. Fluorescence resonance energy transfer between perylene and riboflavin in micellar solution and analytical application on determination of vitamin B2

    International Nuclear Information System (INIS)

    Bhattar, S.L.; Kolekar, G.B.; Patil, S.R.

    2008-01-01

    Fluorescence resonance energy transfer (FRET) between perylene and riboflavin is studied in micellar solution of sodium dodecyl sulfate. The fluorescence of perylene is quenched by riboflavin and quenching is in accordance with Stern-Volmer relation. The efficiency of energy transfer is found to depend on the concentration of riboflavin. The value of critical energy transfer distance (R 0 ) calculated by using Foster relation is 32.13 A, and as it is less than 50 A, it indicates efficient energy transfer in the present system. The analytical relation was established between extent of sensitization and concentration of riboflavin, which helped to estimate vitamin B 2 directly from pharmaceutical tablets

  3. Thoracoamniotic shunting for fetal pleural effusion with hydropic change using a double-basket catheter: An insight into the preoperative determinants of shunting efficacy.

    Science.gov (United States)

    Hidaka, Nobuhiro; Kido, Saki; Sato, Yuka; Murata, Masaharu; Fujita, Yasuyuki; Kato, Kiyoko

    2018-02-01

    Although the efficacy of thoracoamniotic shunting (TAS) for fetal hydrothorax is well-recognized, the coexistence of hydrops fetalis is still a clinical challenge. The preoperative determinants of shunting efficacy are not fully understood. In this study, we aimed to investigate the perinatal and postnatal outcomes of hydrops fetalis with pleural effusion treated by TAS using a double-basket catheter, and to discuss the preoperative factors predictive of patients who will benefit from TAS. We conducted a retrospective study in hydropic fetuses with pleural effusion treated by TAS between 2007 and 2015. We extracted information regarding postnatal survival and pretherapeutic sonographic findings, including skin-edema thickness, pleural-effusion pocket size, and Doppler readings. Twelve subjects underwent TAS at a median gestational age of 29 +5 weeks (range, 25 +5 -33 +2 weeks). Skin edema disappeared or regressed in 7. Three experienced early neonatal death and the other 9 ultimately survived after a live birth at a median gestational age of 33 +4 weeks (range, 29 +1 -38 +2 weeks). All surviving children, except for 1, had a pretherapeutic pleural-effusion pocket greater than the precordial-edema thickness. All 3 children that died had precordial-edema thickness equal to or greater than the size of the pleural-effusion pocket. We achieved a high survival rate (75%) using the double-basket technique. A greater pretherapeutic width of skin edema compared with the pleural-effusion pocket is possibly suggestive of a treatment-resistant condition and subsequent poor postnatal outcome. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. A Determination of the 2200 m/s Absorption Cross Section and Resonance Integral of Arsenic by Pile Oscillator Technique

    Energy Technology Data Exchange (ETDEWEB)

    Sokolowski, E K; Bladh, R

    1969-02-15

    Pile oscillator measurements of heavy-water solutions of As, B, Mn and In have been carried out in two different neutron spectra in the R0 reactor. For B, Mn and In the 2200 m/s cross section values recommended in BNL-325 are given to within 1.5 % or less, while for As the stated uncertainty is 5 %. In the present work the BNL values for B, Mn and In were used to derive weighted mean calibration constants for the reactor, which were then in turn used for obtaining self-consistent cross section values for all four elements. The values thus obtained for B, Mn and In were within experimental error of the recommended BNL values. The absorption cross section for As is in good agreement with a recently published value for the activation cross section. The value for the resonance integral of As, derived from the present measurements, is in better agreement with calculations from resonance parameters than values reported earlier.

  5. A Determination of the 2200 m/s Absorption Cross Section and Resonance Integral of Arsenic by Pile Oscillator Technique

    International Nuclear Information System (INIS)

    Sokolowski, E.K.; Bladh, R.

    1969-02-01

    Pile oscillator measurements of heavy-water solutions of As, B, Mn and In have been carried out in two different neutron spectra in the R0 reactor. For B, Mn and In the 2200 m/s cross section values recommended in BNL-325 are given to within 1.5 % or less, while for As the stated uncertainty is 5 %. In the present work the BNL values for B, Mn and In were used to derive weighted mean calibration constants for the reactor, which were then in turn used for obtaining self-consistent cross section values for all four elements. The values thus obtained for B, Mn and In were within experimental error of the recommended BNL values. The absorption cross section for As is in good agreement with a recently published value for the activation cross section. The value for the resonance integral of As, derived from the present measurements, is in better agreement with calculations from resonance parameters than values reported earlier

  6. Double Trouble

    NARCIS (Netherlands)

    Elsaesser, Thomas; Kievit, Robert; Simons, Jan

    1994-01-01

    Double Trouble highlights the career of Dutch scriptwriter and television producer Chiem van Houweninge, well-known for his long-running TV comedy series and as author of episodes for TV detective series. Double Trouble gives Van Houweninge's own views on writing and filming in television prime

  7. The roles of Dmrt (Double sex/Male-abnormal-3 Related Transcription factor) genes in sex determination and differentiation mechanisms: Ubiquity and diversity across the animal kingdom.

    Science.gov (United States)

    Picard, Marion Anne-Lise; Cosseau, Céline; Mouahid, Gabriel; Duval, David; Grunau, Christoph; Toulza, Ève; Allienne, Jean-François; Boissier, Jérôme

    2015-07-01

    The Dmrt (Double sex/Male-abnormal-3 Related Transcription factor) genes have been intensively studied because they represent major transcription factors in the pathways governing sex determination and differentiation. These genes have been identified in animal groups ranging from cnidarians to mammals, and some of the genes functionally studied. Here, we propose to analyze (i) the presence/absence of various Dmrt gene groups in the different taxa across the animal kingdom; (ii) the relative expression levels of the Dmrt genes in each sex; (iii) the specific spatial (by organ) and temporal (by developmental stage) variations in gene expression. This review considers non-mammalian animals at all levels of study (i.e. no particular importance is given to animal models), and using all types of sexual strategy (hermaphroditic or gonochoric) and means of sex determination (i.e. genetic or environmental). To conclude this global comparison, we offer an analysis of the DM domains conserved among the different DMRT proteins, and propose a general sex-specific pattern for each member of the Dmrt gene family. Copyright © 2015 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  8. The yield of DNA double strand breaks determined after exclusion of those forming from heat-labile lesions predicts tumor cell radiosensitivity to killing.

    Science.gov (United States)

    Cheng, Yanlei; Li, Fanghua; Mladenov, Emil; Iliakis, George

    2015-09-01

    The radiosensitivity to killing of tumor cells and in-field normal tissue are key determinants of radiotherapy response. In vitro radiosensitivity of tumor- and normal-tissue-derived cells often predicts radiation response, but high determination cost in time and resources compromise utility as routine response-predictor. Efforts to use induction or repair of DNA double-strand-breaks (DSBs) as surrogate-predictors of cell radiosensitivity to killing have met with limited success. Here, we re-visit this issue encouraged by our recent observations that ionizing radiation (IR) induces not only promptly-forming DSBs (prDSBs), but also DSBs developing after irradiation from the conversion to breaks of thermally-labile sugar-lesions (tlDSBs). We employ pulsed-field gel-electrophoresis and flow-cytometry protocols to measure total DSBs (tDSB=prDSB+tlDSBs) and prDSBs, as well as γH2AX and parameters of chromatin structure. We report a fully unexpected and in many ways unprecedented correlation between yield of prDSBs and radiosensitivity to killing in a battery of ten tumor cell lines that is not matched by yields of tDSBs or γH2AX, and cannot be explained by simple parameters of chromatin structure. We propose the introduction of prDSBs-yield as a novel and powerful surrogate-predictor of cell radiosensitivity to killing with potential for clinical application. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  9. Effects of dynamic diffraction conditions on magnetic parameter determination in a double perovskite Sr_2FeMoO_6 using electron energy-loss magnetic chiral dichroism

    International Nuclear Information System (INIS)

    Wang, Z.C.; Zhong, X.Y.; Jin, L.; Chen, X.F.; Moritomo, Y.; Mayer, J.

    2017-01-01

    Electron energy-loss magnetic chiral dichroism (EMCD) spectroscopy, which is similar to the well-established X-ray magnetic circular dichroism spectroscopy (XMCD), can determine the quantitative magnetic parameters of materials with high spatial resolution. One of the major obstacles in quantitative analysis using the EMCD technique is the relatively poor signal-to-noise ratio (SNR), compared to XMCD. Here, in the example of a double perovskite Sr_2FeMoO_6, we predicted the optimal dynamical diffraction conditions such as sample thickness, crystallographic orientation and detection aperture position by theoretical simulations. By using the optimized conditions, we showed that the SNR of experimental EMCD spectra can be significantly improved and the error of quantitative magnetic parameter determined by EMCD technique can be remarkably lowered. Our results demonstrate that, with enhanced SNR, the EMCD technique can be a unique tool to understand the structure-property relationship of magnetic materials particularly in the high-density magnetic recording and spintronic devices by quantitatively determining magnetic structure and properties at the nanometer scale. - Highlights: • We demonstrate how to choose the optimal experimental conditions by using dynamical diffraction calculations in Sr_2FeMoO_6. • With optimized diffraction conditions, the signal-to-noise ratio of experimental EMCD spectra has been significantly improved. • We have determined orbital to spin magnetic moment ratio of Sr_2FeMoO_6 quantitatively. • We have discussed the effects of dynamical diffraction conditions on the error bar of quantitative magnetic parameters.

  10. A conformational study of protonated noradrenaline by UV-UV and IR dip double resonance laser spectroscopy combined with an electrospray and a cold ion trap method.

    Science.gov (United States)

    Wako, Hiromichi; Ishiuchi, Shun-Ichi; Kato, Daichi; Féraud, Géraldine; Dedonder-Lardeux, Claude; Jouvet, Christophe; Fujii, Masaaki

    2017-05-03

    The conformer-selected ultraviolet (UV) and infrared (IR) spectra of protonated noradrenaline were measured using an electrospray/cryogenic ion trap technique combined with photo-dissociation spectroscopy. By comparing the UV photo dissociation (UVPD) spectra with the UV-UV hole burning (HB) spectra, it was found that five conformers coexist under ultra-cold conditions. Based on the spectral features of the IR dip spectra of each conformer, two different conformations on the amine side chain were identified. Three conformers (group I) were assigned to folded and others (group II) to extended structures by comparing the observed IR spectra with the calculated ones. Observation of the significantly less-stable extended conformers strongly suggests that the extended structures are dominant in solution and are detected in the gas phase by kinetic trapping. The conformers in each group are assignable to rotamers of OH orientations in the catechol ring. By comparing the UV-UV HB spectra and the calculated Franck-Condon spectra obtained by harmonic vibrational analysis of the S 1 state, with the aid of relative stabilization energies of each conformer in the S 0 state, the absolute orientations of catechol OHs of the observed five conformers were successfully determined. It was found that the 0-0 transition of one folded conformer is red-shifted by about 1000 cm -1 from the others. The significant red-shift was explained by a large contribution of the πσ* state to S 1 in the conformer in which an oxygen atom of the meta-OH group is close to the ammonium group.

  11. Experimental Determination of Operating and Maximum Power Transfer Efficiencies at Resonant Frequency in a Wireless Power Transfer System using PP Network Topology with Top Coupling

    Science.gov (United States)

    Ramachandran, Hema; Pillai, K. P. P.; Bindu, G. R.

    2017-08-01

    A two-port network model for a wireless power transfer system taking into account the distributed capacitances using PP network topology with top coupling is developed in this work. The operating and maximum power transfer efficiencies are determined analytically in terms of S-parameters. The system performance predicted by the model is verified with an experiment consisting of a high power home light load of 230 V, 100 W and is tested for two forced resonant frequencies namely, 600 kHz and 1.2 MHz. The experimental results are in close agreement with the proposed model.

  12. Magnetic resonance imaging-determined synovial membrane and joint effusion volumes in rheumatoid arthritis and osteoarthritis: comparison with the macroscopic and microscopic appearance of the synovium

    DEFF Research Database (Denmark)

    Østergaard, Mikkel; Stoltenberg, M; Løvgreen-Nielsen, P

    1997-01-01

    OBJECTIVE: To evaluate the relationship between synovial membrane and joint effusion volumes determined by magnetic resonance imaging (MRI) and macroscopic and microscopic synovial pathologic findings in patients with rheumatoid arthritis (RA) and osteoarthritis (OA). METHODS: Synovial biopsies...... were performed, and macroscopic grades of synovitis assigned, at preselected knee sites during arthroscopy or arthrotomy in 17 knees with RA and 25 with OA. Synovial inflammation and 9 separate tissue characteristics were graded histologically. Synovial membrane and joint effusion volumes were...... membrane and effusion volumes may be sensitive markers and/or predictors of disease activity and treatment outcome in RA....

  13. Quantum mechanical resonances

    International Nuclear Information System (INIS)

    Cisneros S, A.; McIntosh, H.V.

    1982-01-01

    A discussion of the nature of quantum mechanical resonances is presented from the point of view of the spectral theory of operators. In the case of Bohr-Feshbach resonances, graphs are presented to illustrate the theory showing the decay of a doubly excited metastable state and the excitation of the resonance by an incident particle with proper energy. A characterization of resonances is given as well as a procedure to determine widths using the spectral density function. A sufficient condition is given for the validity of the Breit-Wigner formula for Bohr-Feshbach resonances. (author)

  14. Systematic errors in the determination of the spectroscopic g-factor in broadband ferromagnetic resonance spectroscopy: A proposed solution

    Science.gov (United States)

    Gonzalez-Fuentes, C.; Dumas, R. K.; García, C.

    2018-01-01

    A theoretical and experimental study of the influence of small offsets of the magnetic field (δH) on the measurement accuracy of the spectroscopic g-factor (g) and saturation magnetization (Ms) obtained by broadband ferromagnetic resonance (FMR) measurements is presented. The random nature of δH generates systematic and opposite sign deviations of the values of g and Ms with respect to their true values. A δH on the order of a few Oe leads to a ˜10% error of g and Ms for a typical range of frequencies employed in broadband FMR experiments. We propose a simple experimental methodology to significantly minimize the effect of δH on the fitted values of g and Ms, eliminating their apparent dependence in the range of frequencies employed. Our method was successfully tested using broadband FMR measurements on a 5 nm thick Ni80Fe20 film for frequencies ranging between 3 and 17 GHz.

  15. Determination of temperature dependence of piezoelectric coefficients matrix of lead zirconate titanate ceramics by quasi-static and resonance method

    Energy Technology Data Exchange (ETDEWEB)

    Li Fei; Xu Zhuo; Wei Xiaoyong; Yao Xi, E-mail: lifei1216@gmail.co [Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education, Xi' an Jiaotong University, Xi' an 710049 (China)

    2009-05-07

    The piezoelectric coefficients (d{sub 33}, -d{sub 31}, d{sub 15}, g{sub 33}, -g{sub 31}, g{sub 15}) of soft and hard lead zirconate titanate ceramics were measured by the quasi-static and resonance methods, at temperatures from 20 to 300 {sup 0}C. The results showed that the piezoelectric coefficients d{sub 33}, -d{sub 31} and d{sub 15} obtained by these two methods increased with increasing temperature for both hard and soft PZT ceramics, while the piezoelectric coefficients g{sub 33}, -g{sub 31} and g{sub 15} decreased with increasing temperature for both hard and soft PZT ceramics. In this paper, the observed results were also discussed in terms of intrinsic and extrinsic contributions to piezoelectric response.

  16. A new method for precise determination of iron, zinc and cadmium stable isotope ratios in seawater by double-spike mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Conway, Tim M., E-mail: conway.tm@gmail.com [Department of Earth and Ocean Sciences, University of South Carolina, Columbia, SC 29208 (United States); Rosenberg, Angela D. [Department of Earth and Ocean Sciences, University of South Carolina, Columbia, SC 29208 (United States); Adkins, Jess F. [California Institute of Technology, Division of Geological and Planetary Sciences, Pasadena, CA 91125 (United States); John, Seth G. [Department of Earth and Ocean Sciences, University of South Carolina, Columbia, SC 29208 (United States)

    2013-09-02

    Graphical abstract: ‘Metal-free’ seawater doped with varying concentrations of ‘zero’ isotope standards, processed through our simultaneous method, and then analyzed by double spike MC-ICPMS for Fe, Zn and Cd isotope ratios. All values were determined within 2 σ error (error bars shown) of zero. -- Highlights: •The first simultaneous method for isotopic analysis of Fe, Zn and Cd in seawater. •Designed for 1 L samples, a 1–20 fold improvement over previous methods. •Low blanks and high precision allow measurement of low concentration samples. •Small volume and fast processing are ideal for high-resolution large-scale studies. •Will facilitate investigation of marine trace-metal isotope cycling. -- Abstract: The study of Fe, Zn and Cd stable isotopes (δ{sup 56}Fe, δ{sup 66}Zn and δ{sup 114}Cd) in seawater is a new field, which promises to elucidate the marine cycling of these bioactive trace metals. However, the analytical challenges posed by the low concentration of these metals in seawater has meant that previous studies have typically required large sample volumes, highly limiting data collection in the oceans. Here, we present the first simultaneous method for the determination of these three isotope systems in seawater, using Nobias PA-1 chelating resin to extract metals from seawater, purification by anion exchange chromatography, and analysis by double spike MC-ICPMS. This method is designed for use on only a single litre of seawater and has blanks of 0.3, 0.06 and <0.03 ng for Fe, Zn and Cd respectively, representing a 1–20 fold reduction in sample size and a 4–130 decrease in blank compared to previously reported methods. The procedure yields data with high precision for all three elements (typically 0.02–0.2‰; 1σ internal precision), allowing us to distinguish natural variability in the oceans, which spans 1–3‰ for all three isotope systems. Simultaneous extraction and purification of three metals makes this method ideal

  17. A new method for precise determination of iron, zinc and cadmium stable isotope ratios in seawater by double-spike mass spectrometry

    International Nuclear Information System (INIS)

    Conway, Tim M.; Rosenberg, Angela D.; Adkins, Jess F.; John, Seth G.

    2013-01-01

    Graphical abstract: ‘Metal-free’ seawater doped with varying concentrations of ‘zero’ isotope standards, processed through our simultaneous method, and then analyzed by double spike MC-ICPMS for Fe, Zn and Cd isotope ratios. All values were determined within 2 σ error (error bars shown) of zero. -- Highlights: •The first simultaneous method for isotopic analysis of Fe, Zn and Cd in seawater. •Designed for 1 L samples, a 1–20 fold improvement over previous methods. •Low blanks and high precision allow measurement of low concentration samples. •Small volume and fast processing are ideal for high-resolution large-scale studies. •Will facilitate investigation of marine trace-metal isotope cycling. -- Abstract: The study of Fe, Zn and Cd stable isotopes (δ 56 Fe, δ 66 Zn and δ 114 Cd) in seawater is a new field, which promises to elucidate the marine cycling of these bioactive trace metals. However, the analytical challenges posed by the low concentration of these metals in seawater has meant that previous studies have typically required large sample volumes, highly limiting data collection in the oceans. Here, we present the first simultaneous method for the determination of these three isotope systems in seawater, using Nobias PA-1 chelating resin to extract metals from seawater, purification by anion exchange chromatography, and analysis by double spike MC-ICPMS. This method is designed for use on only a single litre of seawater and has blanks of 0.3, 0.06 and <0.03 ng for Fe, Zn and Cd respectively, representing a 1–20 fold reduction in sample size and a 4–130 decrease in blank compared to previously reported methods. The procedure yields data with high precision for all three elements (typically 0.02–0.2‰; 1σ internal precision), allowing us to distinguish natural variability in the oceans, which spans 1–3‰ for all three isotope systems. Simultaneous extraction and purification of three metals makes this method ideal for high

  18. Ultratrace determination of arsenic in water samples by electrothermal atomic absorption spectrometry after pre-concentration with Mg-Al-Fe ternary layered double hydroxide nano-sorbent.

    Science.gov (United States)

    Abdolmohammad-Zadeh, Hossein; Jouyban, Abolghasem; Amini, Roghayeh

    2013-11-15

    A selective solid phase extraction method, based on nano-structured Mg-Al-Fe(NO3(-)) ternary layered double hydroxide as a sorbent, is developed for the pre-concentration of ultra-trace levels of arsenic (As) prior to determination by electrothermal atomic absorption spectrometry. It is found that both As(III) and As(V) could be quantitatively retained on the sorbent within a wide pH range of 4-12. Accordingly, the presented method is applied to determination of total inorganic As in aqueous solutions. Maximum analytical signal of As is achieved when the pyrolysis and atomization temperatures are close to 900 °C and 2300 °C, respectively. Several variables affecting the extraction efficiency including pH, sample flow rate, amount of nano-sorbent, elution conditions and sample volume are optimized. Under the optimized conditions, the limit of detection (3Sb/m) and the relative standard deviation are 4.6 pg mL(-1) and 3.9%, respectively. The calibration graph is linear in the range of 15.0-650 pg mL(-1) with a correlation coefficient of 0.9979, sorption capacity and pre-concentration factor are 8.68 mg g(-1) and 300, respectively. The developed method is validated by the analysis of a standard reference material (SRM 1643e) and is successfully applied to the determination of ultra-trace amounts of As in different water samples. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Application of double-spike isotope dilution for the accurate determination of Cr(III), Cr(VI) and total Cr in yeast.

    Science.gov (United States)

    Yang, Lu; Ciceri, Elena; Mester, Zoltán; Sturgeon, Ralph E

    2006-11-01

    A method is presented for the simultaneous determination of Cr(III) and Cr(VI) in yeast using species-specific double-spike isotope dilution (SSDSID) with anion-exchange liquid chromatography (LC) separation and sector field inductively coupled plasma mass spectrometric (SF-ICP-MS) detection. Total Cr is quantitated using ID SF-ICP-MS. Samples were digested on a hot plate at 95+/-2 degrees C for 6 h in an alkaline solution of 0.5 M NaOH and 0.28 M Na2CO3 for the determination of Cr(III) and Cr(VI), whereas microwave-assisted decomposition with HNO3 and H2O2 was used for the determination of total Cr. Concentrations of 2,014+/-16, 1,952+/-103 and 76+/-48 mg kg-1 (one standard deviation, n=4, 3, 3), respectively were obtained for total Cr, Cr(III) and Cr(VI) in the yeast sample. Significant oxidation of Cr(III) to Cr(VI) (24.2+/-7.6% Cr(III) oxidized, n=3) and reduction of Cr(VI) to Cr(III) (37.6+/-6.5% Cr(VI) reduced, n=3) occurred during alkaline extraction and subsequent chromatographic separation at pH 7. Despite this significant bidirectional redox transformation, quantitative recoveries for both Cr(III) and Cr(VI) were achieved using the SSDSID method. In addition, mass balance between total Cr and the sum of Cr(III) and Cr(VI) concentrations was achieved. Method detection limits of 0.3, 2 and 30 mg kg-1 were obtained for total Cr, Cr(VI) and Cr(III), respectively, based on a 0.2-g sub-sample.

  20. Functional brain activity changes after four weeks supplementation with a multi-vitamin/mineral combination: A randomized, double-blind, placebo-controlled trial exploring functional Magnetic Resonance Imaging and Steady-State Visual Evoked Potentials during working memory

    Directory of Open Access Journals (Sweden)

    David J White

    2016-12-01

    Full Text Available This study explored the neurocognitive effects of four weeks daily supplementation with a multivitamin and mineral combination (MVM in healthy adults (aged 18-40 years. Using a randomized, double-blind, placebo-controlled design, participants underwent assessments of brain activity using functional Magnetic Resonance Imaging (fMRI; n=32, 16 females and Steady-State Visual Evoked Potential recordings (SSVEP; n=39, 20 females during working memory and continuous performance tasks at baseline and following four weeks of active MVM treatment or placebo. There were several treatment-related effects suggestive of changes in functional brain activity associated with MVM administration. SSVEP data showed latency reductions across centro-parietal regions during the encoding period of a spatial working memory task following four weeks of active MVM treatment. Complementary results were observed with the fMRI data, in which a subset of those completing fMRI assessment after SSVEP assessment (n=16 demonstrated increased BOLD response during completion of the Rapid Visual Information Processing task (RVIP within regions of interest including bilateral parietal lobes. No treatment-related changes in fMRI data were observed in those who had not first undergone SSVEP assessment, suggesting these results may be most evident under conditions of fatigue. Performance on the working memory and continuous performance tasks did not significantly differ between treatment groups at follow-up. In addition, within the fatigued fMRI sample, increased RVIP BOLD response was correlated with the change in number of target detections as part of the RVIP task. This study provides preliminary evidence of changes in functional brain activity during working memory associated with four weeks of daily treatment with a multivitamin and mineral combination in healthy adults, using two distinct but complementary measures of functional brain activity.

  1. Determining metal ion distributions using resonant scattering at very high-energy K-edges: Bi/Pb in Pb5Bi6Se14

    International Nuclear Information System (INIS)

    Zhang Yuegang; Lee, P.L.; Shastri, S.D.; Shu Deming; Wilkinson, A.P.; Chung Duck-Young; Kanatzidis, M.G.

    2005-01-01

    Powder diffraction data collected at ∝ 86 keV, and just below both the Pb and the Bi K-edges, on an imaging plate detector using synchrotron radiation from the Advanced Photon Source have been used to examine the Pb/Bi distribution over the 11 crystallographically distinct sites in Pb 5 Bi 6 Se 14 [space group P2 1 /m, a=16.0096(2) Aa, b=4.20148(4) Aa, c=21.5689(3) Aa and β=97.537(1) 0 ]. The scattering factors needed for the analyses were determined both by Kramers- Kronig transformation of absorption spectra and by analyses of diffraction patterns from reference compounds. Even with the relatively low scattering contrast that is available at the K-edges, it was possible to determine the Pb/Bi distribution and probe the presence of cation site vacancies in the material. The current results indicate that resonant scattering measurements at high-energy K-edges are a viable, and perhaps preferable, route to site occupancies when absorption from the sample or sample environment/container is a major barrier to the acquisition of high-quality resonant scattering data at lower-energy edges

  2. Synthesis, characterization, single crystal X-ray determination, fluorescence and electrochemical studies of new dinuclear nickel(II) and oxovanadium(IV) complexes containing double Schiff base ligands

    Science.gov (United States)

    Shafaatian, Bita; Ozbakzaei, Zahra; Notash, Behrouz; Rezvani, S. Ahmad

    2015-04-01

    A series of new bimetallic complexes of nickel(II) and vanadium(IV) have been synthesized by the reaction of the new double bidentate Schiff base ligands with nickel acetate and vanadyl acetylacetonate in 1:1 M ratio. In nickel and also vanadyl complexes the ligands were coordinated to the metals via the imine N and enolic O atoms. The complexes have been found to possess 1:1 metals to ligands stoichiometry and the molar conductance data revealed that the metal complexes were non-electrolytes. The nickel and vanadyl complexes exhibited distorted square planar and square pyramidal coordination geometries, respectively. The emission spectra of the ligands and their complexes were studied in methanol. Electrochemical properties of the ligands and their metal complexes were also investigated in DMSO solvent at 150 mV s-1 scan rate. The ligands and metal complexes showed both quasi-reversible and irreversible processes at this scan rate. The Schiff bases and their complexes have been characterized by FT-IR, 1H NMR, UV/Vis spectroscopies, elemental analysis and conductometry. The crystal structure of the nickel complex has been determined by single crystal X-ray diffraction.

  3. A randomized, double-blind, placebo-controlled field trial to determine the efficacy and safety of Malarone (atovaquone/proguanil) for the prophylaxis of malaria in Zambia.

    Science.gov (United States)

    Sukwa, T Y; Mulenga, M; Chisdaka, N; Roskell, N S; Scott, T R

    1999-04-01

    Malaria poses a major health risk to people who are exposed to infection in malaria-endemic areas. A randomized, double-blind, placebo-controlled study was conducted to determine the efficacy and safety of Malarone (250 mg of atovaquone/100 mg of proguanil hydrochloride per tablet) for the chemoprophylaxis of Plasmodium falciparum malaria in Zambia. Adult volunteers received a three-day treatment course of Malarone to eliminate pre-existing parasitemia and were then immediately randomized to treatment with either one Malarone tablet daily (n = 136), or one placebo tablet daily (n = 138) for at least 10 weeks. Malaria blood smears were prepared on a weekly basis and a failure of chemoprophylaxis was defined as any subject who had a positive blood smear, or who withdrew from the study due to a treatment-related adverse event. The prophylaxis success rates in the Malarone and placebo groups were 98% and 63%, respectively (P < 0.001). The most commonly reported adverse events with at least a possible causal relationship to study medication were headache and abdominal pain, which occurred with a higher incidence in the placebo group. No subjects were withdrawn from the study due to a treatment-related adverse event. Thus, Malarone appears to have an excellent safety and efficacy profile for the chemoprophylaxis of P. falciparum infection.

  4. In Vitro Activation of eNOS by Mangifera indica (Careless™) and Determination of an Effective Dosage in a Randomized, Double-Blind, Human Pilot Study on Microcirculation.

    Science.gov (United States)

    Gerstgrasser, Alexandra; Röchter, Sigrid; Dressler, Dirk; Schön, Christiane; Reule, Claudia; Buchwald-Werner, Sybille

    2016-03-01

    Mangifera indica fruit preparation (Careless™) activates the evolutionary conserved metabolic sensors sirtuin 1 and adenosine monophosphate-activated protein kinase, which have been identified as playing a key role in microcirculation and endothelial function. Here, an acute effect of a single dose of 100 mg or 300 mg Careless™ on microcirculation was investigated in a randomized, double-blind, crossover pilot study in ten healthy women to determine the effective dosage. Microcirculation and endothelial function were assessed by the Oxygen-to-see system and pulse amplitude tonometry (EndoPAT™), respectively. Cutaneous blood flow was increased over time by 100 mg (54% over pre-values, p = 0.0157) and 300 mg (35% over pre-value, p = 0.209) Careless™. The EndoPAT™ reactive hyperemia response was slightly improved 3 h after intake compared to pretesting with 300 mg Careless™. Furthermore, activation of endothelial nitric oxide synthase, as an important regulator for endothelial function, was tested in vitro in primary human umbilical vein endothelial cells. Careless™, after simulation of digestion, increased the activated form of endothelial nitric oxide synthase dose-dependently by 23% (300 µg/mL), 42% (1500 µg/mL), and 60% (3000 µg/mL) compared to the untreated control. In conclusion, the study suggests moderate beneficial effects of Careless™ on microcirculation, which is at least partly mediated by endothelial nitric oxide synthase activation. Georg Thieme Verlag KG Stuttgart · New York.

  5. The use of dissolvable layered double hydroxide components in an in situ solid-phase extraction for chromatographic determination of tetracyclines in water and milk samples.

    Science.gov (United States)

    Phiroonsoontorn, Nattaphorn; Sansuk, Sira; Santaladchaiyakit, Yanawath; Srijaranai, Supalax

    2017-10-13

    This research presents a simple and green in situ solid phase extraction (is-SPE) combined with high-performance liquid chromatography (HPLC) for the simultaneous analysis of tetracyclines (TCs) including tetracycline, oxytetracycline, and chlortetracycline. In is-SPE, TCs were efficiently extracted through the precipitation formation of dissolvable layered double hydroxides (LDHs) by mixing the LDH components such as magnesium and aluminum ions (both in metal chloride salts) thoroughly in an alkaline sample solution. After the centrifugation, the precipitate was completely dissolved with trifluoroacetic acid to release the enriched TCs, and then analyzed by HPLC. Under optimized conditions, this method gave good enrichment factors (EFs) of 41-93 with low limits of detection (LODs) of 0.7-6μg/L and limits of quantitation (LOQs) of 3-15μg/L. Also, the proposed method was successfully applied for the determination of TCs in water and milk samples with the recoveries ranging from 81.7-108.1% for water and 55.7-88.7% for milk. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. A new method for precise determination of iron, zinc and cadmium stable isotope ratios in seawater by double-spike mass spectrometry.

    Science.gov (United States)

    Conway, Tim M; Rosenberg, Angela D; Adkins, Jess F; John, Seth G

    2013-09-02

    The study of Fe, Zn and Cd stable isotopes (δ(56)Fe, δ(66)Zn and δ(114)Cd) in seawater is a new field, which promises to elucidate the marine cycling of these bioactive trace metals. However, the analytical challenges posed by the low concentration of these metals in seawater has meant that previous studies have typically required large sample volumes, highly limiting data collection in the oceans. Here, we present the first simultaneous method for the determination of these three isotope systems in seawater, using Nobias PA-1 chelating resin to extract metals from seawater, purification by anion exchange chromatography, and analysis by double spike MC-ICPMS. This method is designed for use on only a single litre of seawater and has blanks of 0.3, 0.06 and <0.03 ng for Fe, Zn and Cd respectively, representing a 1-20 fold reduction in sample size and a 4-130 decrease in blank compared to previously reported methods. The procedure yields data with high precision for all three elements (typically 0.02-0.2‰; 1σ internal precision), allowing us to distinguish natural variability in the oceans, which spans 1-3‰ for all three isotope systems. Simultaneous extraction and purification of three metals makes this method ideal for high-resolution, large-scale endeavours such as the GEOTRACES program. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Analysis of the sensitivity of the impact resonance frequency test as a tool to determine the elastic properties of bituminous materials

    International Nuclear Information System (INIS)

    Tauste, R.; Moreno-Navarro, F.; Gallego, R.; Rubio-Gámez, M.C.

    2017-01-01

    The modulus value of bituminous materials is a key factor in the design of road pavements and the estimation of their life service. This parameter can be measured in laboratory but, unfortunately, this requires the deterioration of the pavement so as the consumption of time and resources. Therefore, this study analyses the feasibility of using impact resonance frequency tests as an alternative to traditional methods for determining the dynamic modulus of bituminous mixtures. The sensitivity of this technique has been studied by analyzing its repeatability and reproducibility, studying the variations in the values measured by modifying the dimensions of the specimens, test temperatures and types of mixture tested. In addition, this non-destructive technique has been compared with other traditional tests used to determine the elastic properties of bituminous materials. The results show that this test could be an interesting tool to characterize the properties and damage state of asphalt layers. [es

  8. Analysis of the sensitivity of the impact resonance frequency test as a tool to determine the elastic properties of bituminous materials

    Directory of Open Access Journals (Sweden)

    R. Tauste

    2017-07-01

    Full Text Available The modulus value of bituminous materials is a key factor in the design of road pavements and the estimation of their life service. This parameter can be measured in laboratory but, unfortunately, this requires the deterioration of the pavement so as the consumption of time and resources. Therefore, this study analyses the feasibility of using impact resonance frequency tests as an alternative to traditional methods for determining the dynamic modulus of bituminous mixtures. The sensitivity of this technique has been studied by analyzing its repeatability and reproducibility, studying the variations in the values measured by modifying the dimensions of the specimens, test temperatures and types of mixture tested. In addition, this non-destructive technique has been compared with other traditional tests used to determine the elastic properties of bituminous materials. The results show that this test could be an interesting tool to characterize the properties and damage state of asphalt layers.

  9. Electron paramagnetic resonance imaging of tumor hypoxia: enhanced spatial and temporal resolution for in vivo pO2 determination.

    Science.gov (United States)

    Matsumoto, Ken-ichiro; Subramanian, Sankaran; Devasahayam, Nallathamby; Aravalluvan, Thirumaran; Murugesan, Ramachandran; Cook, John A; Mitchell, James B; Krishna, Murali C

    2006-05-01

    The time-domain (TD) mode of electron paramagnetic resonance (EPR) data collection offers a means of estimating the concentration of a paramagnetic probe and the oxygen-dependent linewidth (LW) to generate pO2 maps with minimal errors. A methodology for noninvasive pO2 imaging based on the application of TD-EPR using oxygen-induced LW broadening of a triarylmethyl (TAM)-based radical is presented. The decay of pixel intensities in an image is used to estimate T2*, which is inversely proportional to pO2. Factors affecting T2* in each pixel are critically analyzed to extract the contribution of dissolved oxygen to EPR line-broadening. Suitable experimental and image-processing parameters were obtained to produce pO2 maps with minimal artifacts. Image artifacts were also minimized with the use of a novel data collection strategy using multiple gradients. Results from a phantom and in vivo imaging of tumor-bearing mice validated this novel method of noninvasive oximetry. The current imaging protocols achieve a spatial resolution of approximately 1.0 mm and a temporal resolution of approximately 9 s for 2D pO2 mapping, with a reliable oxygen resolution of approximately 1 mmHg (0.12% oxygen in gas phase). This work demonstrates that in vivo oximetry can be performed with good sensitivity, accuracy, and high spatial and temporal resolution.

  10. Double-blind placebo-controlled food challenges in children with alleged cow's milk allergy: prevention of unnecessary elimination diets and determination of eliciting doses.

    Science.gov (United States)

    Dambacher, Wendy M; de Kort, Ellen H M; Blom, W Marty; Houben, Geert F; de Vries, Esther

    2013-02-08

    Children with cow's milk allergy (CMA) need a cow's milk protein (CMP) free diet to prevent allergic reactions. For this, reliable allergy-information on the label of food products is essential to avoid products containing the allergen. On the other hand, both overzealous labeling and misdiagnosis that result in unnecessary elimination diets, can lead to potentially hazardous health situations. Our objective was to evaluate if excluding CMA by double-blind placebo-controlled food challenge (DBPCFC) prevents unnecessary elimination diets in the long term. Secondly, to determine the minimum eliciting dose (MED) for an acute allergic reaction to CMP in DBPCFC positive children. All children with suspected CMA under our care (Oct'05-Jun'09) were prospectively enrolled in a DBPCFC. Placebo and verum feedings were administered on two randomly assigned separate days. The MED was determined by noting the 'lowest observed adverse effect level' (LOAEL) in DBPCFC-positive children. Based on the outcomes of the DBPCFC a dietary advice was given. Parents were contacted by phone several months later about the diet of their child. 116 children were available for analysis. In 76 children CMA was rejected. In 60 of them CMP was successfully reintroduced, in 2 the parents refused introduction, in another 3 the parents stopped reintroduction. In 9 children CMA symptoms reappeared. In 40 children CMA was confirmed. Infants aged ≤ 12 months in our study group have a higher cumulative distribution of MED than older children. Excluding CMA by DBPCFC successfully stopped unnecessary elimination diets in the long term in most children. The MEDs form potential useful information for offering dietary advice to patients and their caretakers.

  11. Double photoionization of strontium

    Energy Technology Data Exchange (ETDEWEB)

    Sokell, Emma; Grimm, Michael; Sheridan, Paul, E-mail: emma.sokell@ucd.i [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland)

    2010-02-01

    Resonant triple-differential cross-section (TDCS) measurements have been used to study the double photoionization process in strontium. Two sets of measurements were made at the photon energy of the 4p {yields} 4d resonance. The coplanar geometry was used and the fixed analyser, positioned at -90{sup 0} to the main axis of polarization of the photons, detected electrons with {approx}65% of the available excess energy. The mutual angle between the two electrons had a range just short of 90 {yields} 270{sup 0}. The TDCS exhibit unexpected lobes at a mutual angle of 180{sup 0}. Comparison with other measurements made with the same geometry but with different sharings of the available energy indicate that these TDCS all show the unexpected lobe. Some possible explanations for the lobe are considered.

  12. Double inflation

    International Nuclear Information System (INIS)

    Silk, J.; Turner, M.S.

    1986-04-01

    The Zel'dovich spectrum of adiabatic density perturbations is a generic prediction of inflation. There is increasing evidence that when the spectrum is normalized by observational data on small scales, there is not enough power on large scales to account for the observed large-scale structure in the Universe. Decoupling the spectrum on large and small scales could solve this problem. As a means of decoupling the large and small scales we propose double inflation (i.e., two episodes of inflation). In this scenario the spectrum on large scales is determined by the first episode of inflation and those on small scales by a second episode of inflation. We present three models for such a scenario. By nearly saturating the large angular-scale cosmic microwave anisotropy bound, we can easily account for the observed large-scale structure. We take the perturbations on small scales to be very large, deltarho/rho approx. = 0.1 to 0.01, which results in the production of primordial black holes (PBHs), early formation of structure, reionization of the Universe, and a rich array of astrophysical events. The Ω-problem is also addressed by our scenario. Allowing the density perturbations produced by the second episode of inflation to be large also lessens the fine-tuning required in the scalar potential and makes reheating much easier. We briefly speculate on the possibility that the second episode of inflation proceeds through the nucleation of bubbles, which today manifest themselves as empty bubbles whose surfaces are covered with galaxies. 37 refs., 1 fig

  13. A multiparametric magnetic resonance imaging-based risk model to determine the risk of significant prostate cancer prior to biopsy.

    Science.gov (United States)

    van Leeuwen, Pim J; Hayen, Andrew; Thompson, James E; Moses, Daniel; Shnier, Ron; Böhm, Maret; Abuodha, Magdaline; Haynes, Anne-Maree; Ting, Francis; Barentsz, Jelle; Roobol, Monique; Vass, Justin; Rasiah, Krishan; Delprado, Warick; Stricker, Phillip D

    2017-12-01

    To develop and externally validate a predictive model for detection of significant prostate cancer. Development of the model was based on a prospective cohort including 393 men who underwent multiparametric magnetic resonance imaging (mpMRI) before biopsy. External validity of the model was then examined retrospectively in 198 men from a separate institution whom underwent mpMRI followed by biopsy for abnormal prostate-specific antigen (PSA) level or digital rectal examination (DRE). A model was developed with age, PSA level, DRE, prostate volume, previous biopsy, and Prostate Imaging Reporting and Data System (PIRADS) score, as predictors for significant prostate cancer (Gleason 7 with >5% grade 4, ≥20% cores positive or ≥7 mm of cancer in any core). Probability was studied via logistic regression. Discriminatory performance was quantified by concordance statistics and internally validated with bootstrap resampling. In all, 393 men had complete data and 149 (37.9%) had significant prostate cancer. While the variable model had good accuracy in predicting significant prostate cancer, area under the curve (AUC) of 0.80, the advanced model (incorporating mpMRI) had a significantly higher AUC of 0.88 (P prostate cancer. Individualised risk assessment of significant prostate cancer using a predictive model that incorporates mpMRI PIRADS score and clinical data allows a considerable reduction in unnecessary biopsies and reduction of the risk of over-detection of insignificant prostate cancer at the cost of a very small increase in the number of significant cancers missed. © 2017 The Authors BJU International © 2017 BJU International Published by John Wiley & Sons Ltd.

  14. Elastic Properties of Novel Co- and CoNi-Based Superalloys Determined through Bayesian Inference and Resonant Ultrasound Spectroscopy

    Science.gov (United States)

    Goodlet, Brent R.; Mills, Leah; Bales, Ben; Charpagne, Marie-Agathe; Murray, Sean P.; Lenthe, William C.; Petzold, Linda; Pollock, Tresa M.

    2018-06-01

    Bayesian inference is employed to precisely evaluate single crystal elastic properties of novel γ -γ ' Co- and CoNi-based superalloys from simple and non-destructive resonant ultrasound spectroscopy (RUS) measurements. Nine alloys from three Co-, CoNi-, and Ni-based alloy classes were evaluated in the fully aged condition, with one alloy per class also evaluated in the solution heat-treated condition. Comparisons are made between the elastic properties of the three alloy classes and among the alloys of a single class, with the following trends observed. A monotonic rise in the c_{44} (shear) elastic constant by a total of 12 pct is observed between the three alloy classes as Co is substituted for Ni. Elastic anisotropy ( A) is also increased, with a large majority of the nearly 13 pct increase occurring after Co becomes the dominant constituent. Together the five CoNi alloys, with Co:Ni ratios from 1:1 to 1.5:1, exhibited remarkably similar properties with an average A 1.8 pct greater than the Ni-based alloy CMSX-4. Custom code demonstrating a substantial advance over previously reported methods for RUS inversion is also reported here for the first time. CmdStan-RUS is built upon the open-source probabilistic programing language of Stan and formulates the inverse problem using Bayesian methods. Bayesian posterior distributions are efficiently computed with Hamiltonian Monte Carlo (HMC), while initial parameterization is randomly generated from weakly informative prior distributions. Remarkably robust convergence behavior is demonstrated across multiple independent HMC chains in spite of initial parameterization often very far from actual parameter values. Experimental procedures are substantially simplified by allowing any arbitrary misorientation between the specimen and crystal axes, as elastic properties and misorientation are estimated simultaneously.

  15. Determination of phosphate compounds in meat products by 31-Phosphorus Nuclear Magnetic Resonance spectroscopy with methylenediphosphonic acid after alkaline extraction

    International Nuclear Information System (INIS)

    Hrynczyszyn, P.; Jastrzebska, A.; Szlyk, E.

    2010-01-01

    Modification of the extraction procedure and application of the 31 P NMR method for the determination of polyphosphates in meat products were studied. In the elaborated procedure threefold water extraction at alkaline pH (borate buffer and 0.1 M EDTA) was applied. Furthermore, the new external standard for 31 P NMR determination of phosphates was proposed. Obtained recoveries were between 95 and 99% and variation coefficients (CV) was ≤5%, indicating an increase in accuracy and the precision of the proposed procedure in relation to the spectrophotometric method. The described procedure of sample preparation with 31 P NMR method was applied for the determination of polyphosphate additives in meat products. The satisfactory precision (CV = 0.39-3.40%) shows the benefit of the NMR method in the routine analysis of the phosphate ions in meat products.

  16. Determination of dextrose in peritoneal dialysis solution by localized surface plasmon resonance technique based on silver nanoparticles formation

    Science.gov (United States)

    Masrournia, Mahboube; Montazarolmahdi, Maliheh; Sani, Faramarz Aliasghari

    2017-07-01

    Determination of dextrose in peritoneal dialysis with a method based on silver nanoparticles (AgNPs) formation was investigated. In a green chemistry method, silver nanoparticles (AgNPs) were synthesized in the natural polymeric matrix of gelatin. The nanoparticles were characterized with UV-Vis spectroscopy and transmission electron microscopy (TEM). Absorbance signal of AgNPs could be applied to determine the various concentrations of dextrose solutions. Drop wise and ultrasonic methods were used and compared with each other. The dynamic range of methods with limit of detection and relative standard deviations were obtained. Results for real sample (peritoneal dialysis) were satisfied.

  17. Ultra violet resonance Raman spectroscopy in lignin analysis: determination of characteristic vibrations of p-hydroxyphenyl, guaiacyl, and syringyl lignin structures.

    Science.gov (United States)

    Saariaho, Anna-Maija; Jääskeläinen, Anna-Stiina; Nuopponen, Mari; Vuorinen, Tapani

    2003-01-01

    Raman spectroscopy of wood and lignin samples is preferably carried out in the near-infrared region because lignin produces an intense laser-induced fluorescence background at visible excitation wavelengths. However, excitation of aromatic and conjugated lignin structures with deep ultra violet (UV) light gives resonance-enhanced Raman signals while the overlapping fluorescence is eliminated. In this study, ultra violet resonance Raman (UVRR) spectroscopy was used to define characteristic vibration bands of model compounds of p-hydroxyphenyl, guaiacyl, and syringyl lignin structures at three excitation wavelengths (229, 244, and 257 nm). The intensities of each band, relative to the intensity of the aromatic vibration band at 1600 cm-1, were defined and the most suitable excitation wavelength was suggested for each structure. p-Hydroxyphenyl structures showed intensive characteristic bands at 1217-1214 and 1179-1167 cm-1 with excitation at 244 nm, whereas the bands of guaiacyl structures were more intensive with 257 nm excitation. Most intensive characteristic bands of guaiacyl structures were found at 1289-1279, 1187-1185, 1158-1155, and 791-704 cm-1. Syringyl structures had almost identical spectra with 244 and 257 nm excitations with characteristic bands at 1514-1506, 1333-1330, and 981-962 cm-1. The characteristic bands of the three structural units were also found from the compression wood, softwood, and hardwood samples, indicating that UVRR spectroscopy can be applied for the determination of chemical structures of lignin.

  18. A Geant4-based Simulation to Evaluate the Feasibility of Using Nuclear Resonance Fluorescence (NRF) in Determining Atomic Compositions of Body Tissue in Cancer Diagnostics and Irradiation

    Science.gov (United States)

    Gilbo, Yekaterina; Wijesooriya, Krishni; Liyanage, Nilanga

    2017-01-01

    Customarily applied in homeland security for identifying concealed explosives and chemical weapons, NRF (Nuclear Resonance Fluorescence) may have high potential in determining atomic compositions of body tissue. High energy photons incident on a target excite the target nuclei causing characteristic re-emission of resonance photons. As the nuclei of each isotope have well-defined excitation energies, NRF uniquely indicates the isotopic content of the target. NRF radiation corresponding to nuclear isotopes present in the human body is emitted during radiotherapy based on Bremsstrahlung photons generated in a linear electron accelerator. We have developed a Geant4 simulation in order to help assess NRF capabilities in detecting, mapping, and characterizing tumors. We have imported a digital phantom into the simulation using anatomical data linked to known chemical compositions of various tissues. Work is ongoing to implement the University of Virginia's cancer center treatment setup and patient geometry, and to collect and analyze the simulation's physics quantities to evaluate the potential of NRF for medical imaging applications. Preliminary results will be presented.

  19. Evaluation of Accordance of Magnetic Resonance Volumetric and Flow Measurements in Determining Ventricular Stroke Volume in Cardiac Patients

    International Nuclear Information System (INIS)

    Jeltsch, M.; Ranft, S.; Klass, O.; Aschoff, A.J.; Hoffmann, M.H.K.

    2008-01-01

    Background: Cardiovascular magnetic resonance imaging (CMR) has become an established noninvasive method for evaluating ventricular function utilizing three-dimensional volumetry. Postprocessing of volumetric measurements is still tedious and time consuming. Stroke volumes obtained by flow quantification across the aortic root or pulmonary trunk could be utilized to increase both speed of workflow and accuracy. Purpose: To assess accuracy of stroke volume quantification using MR volumetric imaging compared to flow quantification in patients with various cardiac diseases. Strategies for the augmentation of accuracy in clinical routine were deduced. Material and Methods: 78 patients with various cardiac diseases -excluding intra- or extracardiac shunts, regurgitant valvular defects, or heart rhythm disturbance -underwent cardiac function analysis with flow measurements across the aortic root and cine imaging of the left ventricle. Forty-six patients additionally underwent flow measurements in the pulmonary trunk and cine imaging of the right ventricle. Results: Left ventricular stroke volume (LVSV) and stroke volume of the aortic root (SVAo) correlated with r=0.97, and Bland-Altman analysis showed a mean difference of 0.11 ml and a standard error of estimation (SEE) of 4.31 ml. Ninety-two percent of the data were within the 95% limits of agreement. Right ventricular stroke volume (RVSV) and stroke volume of the pulmonary trunk (SVP) correlated with a factor of r=0.86, and mean difference in the Bland-Altman analysis was fixed at -2.62 ml (SEE 8.47 ml). For RVSV and SVP, we calculated r=0.82, and Bland-Altman analysis revealed a mean difference of 1.27 ml (SEE 9.89 ml). LVSV and RVSV correlated closely, with r=0.91 and a mean difference of 2.79 ml (SEE 7.17 ml). SVAo and SVP correlated with r=0.95 and a mean difference of 0.50 ml (SEE 5.56 ml). Conclusion: Flow quantification can be used as a guidance tool, providing accurate and reproducible stroke volumes of both

  20. Determination of Temperature-Dependent Stress State in Thin AlGaN Layer of AlGaN/GaN HEMT Heterostructures by Near-Resonant Raman Scattering

    OpenAIRE

    Yanli Liu; Xifeng Yang; Dunjun Chen; Hai Lu; Rong Zhang; Youdou Zheng

    2015-01-01

    The temperature-dependent stress state in the AlGaN barrier layer of AlGaN/GaN heterostructure grown on sapphire substrate was investigated by ultraviolet (UV) near-resonant Raman scattering. Strong scattering peak resulting from the A1(LO) phonon mode of AlGaN is observed under near-resonance condition, which allows for the accurate measurement of Raman shifts with temperature. The temperature-dependent stress in the AlGaN layer determined by the resonance Raman spectra is consistent with th...