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Sample records for 2d correlation spectrum

  1. Simulation study of 2D spectrum of molecular aggregates coupled to correlated vibrations

    NASA Astrophysics Data System (ADS)

    Abramavicius, Darius; Butkus, Vytautas; Valkunas, Leonas; Mukamel, Shaul

    2011-03-01

    Oscillatory dynamics of two-dimensional (2D) spectra of photosynthetic pigment-protein complexes raise the questions of how to disentangle various origins of these oscillations, which may include quantum beats, quantum transport, or molecular vibrations. We study the effects of correlated overdamped fluctuations and under-damped vibrations on the 2D spectra of Fenna-Matthews-Olson (FMO) aggregate, which has well-resolved exciton resonances, and a circular porphyrin aggregate (P6), whose absorption shows vibrational progression. We use a generic exciton Hamiltonian coupled to a bath, characterized by a spectral density. Fluctuations have smooth, while vibtations have δ -type spectral densities. We show how various scenarios of correlated molecular fluctuations lead to some highly oscillatory crosspeaks. Molecular vibrations cause progression of diagonal peaks in the 2D spectrum and make their corresponding cross-peaks highly oscillatory. We, thus, demonstrate that bath fluctuations and molecular vibrations of realistic molecular aggregates are highly entangled in 2D spectroscopy. DA acknowledges grant VP1-3.1-SMM-07-V, SM - the grants CHE0745892 (NSF), DRPA BAA-10-40 QUBE.

  2. Noninvasive deep Raman detection with 2D correlation analysis

    NASA Astrophysics Data System (ADS)

    Kim, Hyung Min; Park, Hyo Sun; Cho, Youngho; Jin, Seung Min; Lee, Kang Taek; Jung, Young Mee; Suh, Yung Doug

    2014-07-01

    The detection of poisonous chemicals enclosed in daily necessaries is prerequisite essential for homeland security with the increasing threat of terrorism. For the detection of toxic chemicals, we combined a sensitive deep Raman spectroscopic method with 2D correlation analysis. We obtained the Raman spectra from concealed chemicals employing spatially offset Raman spectroscopy in which incident line-shaped light experiences multiple scatterings before being delivered to inner component and yielding deep Raman signal. Furthermore, we restored the pure Raman spectrum of each component using 2D correlation spectroscopic analysis with chemical inspection. Using this method, we could elucidate subsurface component under thick powder and packed contents in a bottle.

  3. Human erythrocytes analyzed by generalized 2D Raman correlation spectroscopy

    NASA Astrophysics Data System (ADS)

    Wesełucha-Birczyńska, Aleksandra; Kozicki, Mateusz; Czepiel, Jacek; Łabanowska, Maria; Nowak, Piotr; Kowalczyk, Grzegorz; Kurdziel, Magdalena; Birczyńska, Malwina; Biesiada, Grażyna; Mach, Tomasz; Garlicki, Aleksander

    2014-07-01

    The most numerous elements of the blood cells, erythrocytes, consist mainly of two components: homogeneous interior filled with hemoglobin and closure which is the cell membrane. To gain insight into their specific properties we studied the process of disintegration, considering these two constituents, and comparing the natural aging process of human healthy blood cells. MicroRaman spectra of hemoglobin within the single RBC were recorded using 514.5, and 785 nm laser lines. The generalized 2D correlation method was applied to analyze the collected spectra. The time passed from blood donation was regarded as an external perturbation. The time was no more than 40 days according to the current storage limit of blood banks, although, the average RBC life span is 120 days. An analysis of the prominent synchronous and asynchronous cross peaks allow us to get insight into the mechanism of hemoglobin decomposition. Appearing asynchronous cross-peaks point towards globin and heme separation from each other, while synchronous shows already broken globin into individual amino acids. Raman scattering analysis of hemoglobin "wrapping", i.e. healthy erythrocyte ghosts, allows for the following peculiarity of their behavior. The increasing power of the excitation laser induced alterations in the assemblage of membrane lipids. 2D correlation maps, obtained with increasing laser power recognized as an external perturbation, allows for the consideration of alterations in the erythrocyte membrane structure and composition, which occurs first in the proteins. Cross-peaks were observed indicating an asynchronous correlation between the senescent-cell antigen (SCA) and heme or proteins vibrations. The EPR spectra of the whole blood was analyzed regarding time as an external stimulus. The 2D correlation spectra points towards participation of the selected metal ion centers in the disintegration process.

  4. Peak width issues with generalised 2D correlation NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Kirwan, Gemma M.; Adams, Michael J.

    2008-12-01

    Two-dimensional spectral correlation analysis is shown to be sensitive to fluctuations in spectral peak width as a function of perturbation variable. This is particularly significant where peak width fluctuations are of similar order of magnitude as the peak width values themselves and where changes in peak width are not random but are, for example, proportional to intensity. In such cases these trends appear in the asynchronous matrix as false peaks that serve to interfere with interpretation of the data. Complex, narrow band spectra such as provided by 1H NMR spectroscopy are demonstrated to be prone to such interference. 2D correlation analysis was applied to a series of NMR spectra corresponding to a commercial wine fermentation, in which the samples collected over a period of several days exhibit dramatic changes in concentration of minor and major components. The interference due to changing peak width effects is eliminated by synthesizing the recorded spectra using a constant peak width value prior to performing 2D correlation analysis.

  5. Transport Experiments on 2D Correlated Electron Physics in Semiconductors

    SciTech Connect

    Tsui, Daniel

    2014-03-24

    This research project was designed to investigate experimentally the transport properties of the 2D electrons in Si and GaAs, two prototype semiconductors, in several new physical regimes that were previously inaccessible to experiments. The research focused on the strongly correlated electron physics in the dilute density limit, where the electron potential energy to kinetic energy ratio rs>>1, and on the fractional quantum Hall effect related physics in nuclear demagnetization refrigerator temperature range on samples with new levels of purity and controlled random disorder.

  6. 2D photonic crystal and its angular reflective azimuthal spectrum

    NASA Astrophysics Data System (ADS)

    Senderakova, Dagmar; Drzik, Milan; Tomekova, Juliana

    2016-12-01

    Contemporary, attention is paid to photonic crystals, which can strongly modify light propagation through them and enable a controllable light manipulation. The contribution is focused on a sub-wavelength 2D structure formed by Al2O3 layer on silicon substrate, patterned with periodic hexagonal lattice of deep air holes. Using various laser sources of light at single wavelength, azimuthal angle dependence of the mirror-like reflected light intensity was recorded photo-electrically. The results obtained can be used to sample the band-structure of leaky modes of the photonic crystal more reliably and help us to map the photonic dispersion diagram.

  7. Roton-maxon excitation spectrum for Q2D weakly interacted dipolar excitons

    NASA Astrophysics Data System (ADS)

    Fedorov, Aleksey; Kurbakov, Igor; Lozovik, Yurii

    2014-03-01

    Remarkable progress was achieved in investigation of collective properties and BEC of quasiparticles, e.g., excitons and polaritons. As it well known their small effective mass provides sufficiently high BEC temperature. However, in reality excitons lifetime is not enough to achieve thermodynamical equilibrium. Spatial separation of electrons and holes in semiconductor layer suppresses recombination process, and exciton lifetime increases sufficiently. Moreover, the separation results in appearance of excitons dipole moments. We predict generation of roton-maxon excitation spectrum for BEC of dipolar excitons in weak correlation regime in Q2D geometry of semiconductor layer. The effect of roton-maxon spectrum is the result of attraction and anisotropy of dipole-dipole interaction in Q2D geometry, and it can be viewed as residual phenomena of phonon collapse for 3D dipoles. According to our estimation effects of BEC and roton-maxon spectrum are principally observable experimentally for excitons in crossed electromagnetic fields in GaAs heterostructures. The work was supported by the RFBR (14-02-00937, 14-08-00606). A.K.F. is an RQC fellow.

  8. Quasiparticle Spectrum of 2-d Dirac Vortices in Optical Lattices

    NASA Astrophysics Data System (ADS)

    Haddad, Laith

    2009-10-01

    Bose-Einstein condensates in a honeycomb optical lattice are described by a nonlinear Dirac equaton (NLDE) in the long wavelength, mean field limit [1]. The upper and lower two-spinor equations decouple and superficially resemble the equations of previously studied NLDE's such as the Soler model for extended fermions. Although much work has been done on NLDE's, the bulk of the literature deals with models with Poincare invariant nonlinearites. In contrast our equations break Poincare symmetry providing an opportunity to study phenomenological models in cosmology and particle physics where this symmetry is not manifest. We obtain and classify localized solutions to our equations for both repulsive and attractive contact interactions. We also derive analogs of the Bogoliubov-de Gennes equations for the lattice and use these to study the stability and low energy spectrum of our solutions showing the existence of stable exotic structures such as vortices with fractional statistics.[4pt] [1] L. H. Haddad and L. D. Carr, ``The Nonlinear Dirac Equation in Bose-Einstein Condensates: Foundation and Symmetries,'' Physica D: Nonlinear Phenomena, v. 238, p. 1413 (2009). http://arxiv.org/pdf/0803.3039v1

  9. 2-D Acousto-Optic Signal Processors for Simultaneous Spectrum Analysis and Direction Finding

    DTIC Science & Technology

    1990-11-01

    National Dfense Defence nationale 2-D ACOUSTO - OPTIC SIGNAL PROCESSORS FOR SIMULTANEOUS SPECTRUM ANALYSIS 00 AND DIRECTION FINDING (U) by NM Jim P.Y...Wr pdft .1w I0~1111191 3 05089 National DIfense Defence nationale 2-D ACOUSTO - OPTIC SIGNAL PROCESSORS FOR SIMULTANEOUS SPECTRUM ANALYSIS AND DIRECTION...Processing, J.T. Tippet et al., Eds., Chapter 38, pp. 715-748, MIT Press, Cambridge 1965. [6] A.E. Spezio," Acousto - optics for Electronic Warfare

  10. [Study on the processing of leech by FTIR and 2D-IR correlation spectroscopy].

    PubMed

    Li, Bing-Ning; Wu, Yan-Wen; Ouyang, Jie; Sun, Su-Qin; Chen, Shun-Cong

    2011-04-01

    The chemical differences of traditional Chinese medicine leech before and after processing were analyzed by FTIR and two-dimensional correlation infrared (2D-IR) spectroscopy. The result showed that the leech was high in protein, with characteristic peaks of amide I, II bands. Comparing the IR spectra of samples, the primary difference was that the characteristic peak of fresh leech was at 1 543 cm(-1), while that of crude and processed leech was at 1 535 cm(-1). A 2D-IR spectrum with heating perturbation was used to track the processing dynamics of leech In the 2D-IR correlation spectra, fresh leech exhibited stronger automatic peaks of the amide I and II bands than that of processed leech, which indicates that the protein components of the fresh leech were more sensitive to heat perturbation than the processed one. Moreover, the result of FTIR and 2D-IR correlation spectra validated that the 3-dimensional structure of protein was damaged and hydrogen bonds were broken after processing, which resulted in the inactivation of protein. The fatty acids and cholesterol components of leech were also oxidized in this process.

  11. The power spectrum of galaxies in the 2dF 100k redshift survey

    NASA Astrophysics Data System (ADS)

    Tegmark, Max; Hamilton, Andrew J. S.; Xu, Yongzhong

    2002-10-01

    We compute the real-space power spectrum and the redshift-space distortions of galaxies in the 2dF 100k galaxy redshift survey using pseudo-Karhunen-Loève eigenmodes and the stochastic bias formalism. Our results agree well with those published by the 2dFGRS team, and have the added advantage of producing easy-to-interpret uncorrelated minimum-variance measurements of the galaxy-galaxy, galaxy-velocity and velocity-velocity power spectra in 27 k-bands, with narrow and well-behaved window functions in the range 0.01 h Mpc-1 < k < 0.8 h Mpc-1. We find no significant detection of baryonic wiggles, although our results are consistent with a standard flat ΩΛ= 0.7`concordance' model and previous tantalizing hints of baryonic oscillations. We measure the galaxy-matter correlation coefficient r > 0.4 and the redshift-distortion parameter β= 0.49 +/- 0.16 for r= 1 (β= 0.47 +/- 0.16 without finger-of-god compression). Since this is an apparent-magnitude limited sample, luminosity-dependent bias may cause a slight red-tilt in the power spectrum. A battery of systematic error tests indicate that the survey is not only impressive in size, but also unusually clean, free of systematic errors at the level to which our tests are sensitive. Our measurements and window functions are available at http://www.hep.upenn.edu/~max/2df.html together with the survey mask, radial selection function and uniform subsample of the survey that we have constructed.

  12. SAW correlator spread spectrum receiver

    DOEpatents

    Brocato, Robert W

    2014-04-01

    A surface acoustic wave (SAW) correlator spread-spectrum (SS) receiver is disclosed which utilizes a first demodulation stage with a chip length n and a second demodulation stage with a chip length m to decode a transmitted SS signal having a code length l=n.times.m which can be very long (e.g. up to 2000 chips or more). The first demodulation stage utilizes a pair of SAW correlators which demodulate the SS signal to generate an appropriate code sequence at an intermediate frequency which can then be fed into the second demodulation stage which can be formed from another SAW correlator, or by a digital correlator. A compound SAW correlator comprising two input transducers and a single output transducer is also disclosed which can be used to form the SAW correlator SS receiver, or for use in processing long code length signals.

  13. Ultrasonic tissue characterization via 2-D spectrum analysis: theory and in vitro measurements.

    PubMed

    Liu, Tian; Lizzi, Frederic L; Ketterling, Jeffrey A; Silverman, Ronald H; Kutcher, Gerald J

    2007-03-01

    A theoretical model is described for application in ultrasonic tissue characterization using a calibrated 2-D spectrum analysis method. This model relates 2-D spectra computed from ultrasonic backscatter signals to intrinsic physical properties of tissue microstructures, e.g., size, shape, and acoustic impedance. The model is applicable to most clinical diagnostic ultrasound systems. Two experiments employing two types of tissue architectures, spherical and cylindrical scatterers, are conducted using ultrasound with center frequencies of 10 and 40 MHz, respectively. Measurements of a tissue-mimicking phantom with an internal suspension of microscopic glass beads are used to validate the theoretical model. Results from in vitro muscle fibers are presented to further elucidate the utility of 2-D spectrum analysis in ultrasonic tissue characterization.

  14. The infrared spectrum of the Ar-C2D2 complex

    NASA Astrophysics Data System (ADS)

    Rezaei, M.; McKellar, A. R. W.; Moazzen-Ahmadi, N.

    2016-10-01

    Infrared spectra of Ar-C2D2 are observed in the region of the ν3 fundamental band (asymmetric C-D stretch, ≈2440 cm-1) using a tunable optical parametric oscillator to probe a pulsed supersonic slit jet expansion from a cooled nozzle. Transitions are assigned involving K = 0-2 in the ground vibrational state, and K = 0-4 in the excited state. The intermolecular bending combination band is also observed, giving a bending frequency of 4.798 cm-1. Despite this low bending frequency, the Ar-C2D2 spectrum qualitatively resembles that of a normal semi-rigid molecule, in contrast to He- and Ne-C2D2 which are much closer to the limit of free internal rotation.

  15. The infrared spectrum of the Ne-C2D2 complex.

    PubMed

    Moazzen-Ahmadi, N; McKellar, A R W; Fernández, Berta; Farrelly, David

    2015-11-28

    Infrared spectra of Ne-C2D2 are observed in the region of the ν3 fundamental band (asymmetric C-D stretch, ≈2440 cm(-1)) using a tunable optical parametric oscillator to probe a pulsed supersonic slit jet expansion from a cooled nozzle. Like helium-acetylene, this system lies close to the free rotor limit, making analysis tricky because stronger transitions tend to pile up close to monomer (C2D2) rotation-vibration transitions. Assignments are aided by predicted rotational energies calculated from a published ab initio intermolecular potential energy surface. The analysis extends up to the j = 3←2 band, where j labels C2D2 rotation within the dimer, and is much more complete than the limited infrared assignments previously reported for Ne-C2H2 and Ne-C2HD. Two previous microwave transitions within the j = 1 state of Ne-C2D2 are reassigned. Coriolis model fits to the theoretical levels and to the spectrum are compared. Since the variations observed as a function of C2D2 vibrational excitation are comparable to those noted between theory and experiment, it is evident that more detailed testing of theory will require vibrational averaging over the acetylene intramolecular modes.

  16. Chemical Shifts to Metabolic Pathways: Identifying Metabolic Pathways Directly from a Single 2D NMR Spectrum.

    PubMed

    Dubey, Abhinav; Rangarajan, Annapoorni; Pal, Debnath; Atreya, Hanudatta S

    2015-12-15

    Identifying cellular processes in terms of metabolic pathways is one of the avowed goals of metabolomics studies. Currently, this is done after relevant metabolites are identified to allow their mapping onto specific pathways. This task is daunting due to the complex nature of cellular processes and the difficulty in establishing the identity of individual metabolites. We propose here a new method: ChemSMP (Chemical Shifts to Metabolic Pathways), which facilitates rapid analysis by identifying the active metabolic pathways directly from chemical shifts obtained from a single two-dimensional (2D) [(13)C-(1)H] correlation NMR spectrum without the need for identification and assignment of individual metabolites. ChemSMP uses a novel indexing and scoring system comprised of a "uniqueness score" and a "coverage score". Our method is demonstrated on metabolic pathways data from the Small Molecule Pathway Database (SMPDB) and chemical shifts from the Human Metabolome Database (HMDB). Benchmarks show that ChemSMP has a positive prediction rate of >90% in the presence of decluttered data and can sustain the same at 60-70% even in the presence of noise, such as deletions of peaks and chemical shift deviations. The method tested on NMR data acquired for a mixture of 20 amino acids shows a success rate of 93% in correct recovery of pathways. When used on data obtained from the cell lysate of an unexplored oncogenic cell line, it revealed active metabolic pathways responsible for regulating energy homeostasis of cancer cells. Our unique tool is thus expected to significantly enhance analysis of NMR-based metabolomics data by reducing existing impediments.

  17. Bond Order Correlations in the 2D Hubbard Model

    NASA Astrophysics Data System (ADS)

    Moore, Conrad; Abu Asal, Sameer; Yang, Shuxiang; Moreno, Juana; Jarrell, Mark

    We use the dynamical cluster approximation to study the bond correlations in the Hubbard model with next nearest neighbor (nnn) hopping to explore the region of the phase diagram where the Fermi liquid phase is separated from the pseudogap phase by the Lifshitz line at zero temperature. We implement the Hirsch-Fye cluster solver that has the advantage of providing direct access to the computation of the bond operators via the decoupling field. In the pseudogap phase, the parallel bond order susceptibility is shown to persist at zero temperature while it vanishes for the Fermi liquid phase which allows the shape of the Lifshitz line to be mapped as a function of filling and nnn hopping. Our cluster solver implements NVIDIA's CUDA language to accelerate the linear algebra of the Quantum Monte Carlo to help alleviate the sign problem by allowing for more Monte Carlo updates to be performed in a reasonable amount of computation time. Work supported by the NSF EPSCoR Cooperative Agreement No. EPS-1003897 with additional support from the Louisiana Board of Regents.

  18. 2D correlation analysis of the magnetic excitations in Raman spectra of HoMnO3

    NASA Astrophysics Data System (ADS)

    Nguyen, Thi Huyen; Nguyen, Thi Minh Hien; Chen, Xiang-Bai; Yang, In-Sang; Park, Yeonju; Jung, Young Mee

    2014-07-01

    2D correlation analysis is performed on the temperature-dependent Raman spectra of HoMnO3 thin films. As the temperature of the HoMnO3 thin films decrease, the depletion of the spectral weight at 336, 656, and 1304 cm-1 occurs at higher temperatures than the increase of the intensity at 508, 766, and 945 cm-1 below ∼70 K, the Néel temperature. The power spectrum asserts that all the changes in the spectral weight are strongly correlated. Most of the temperature-induced spectral changes of HoMnO3 occur at lower temperature than 70 K, while there is slight depletion of the spectral weight at 336, 656, and 1304 cm-1 even at higher temperature than 70 K. PCA scores and loading vectors plots also support these 2D correlation results. Our 2D correlation analysis supports the existence of the short range spin correlations between Mn sites in HoMnO3 even above the Néel temperature.

  19. 2D focal-field aberration dependence on time/phase screen position and correlation lengths

    NASA Astrophysics Data System (ADS)

    Näsholm, Sven Peter

    2004-05-01

    For high-frequency annular array transducers used in medical ultrasound imaging, aberrations due to tissue and body wall have a significant effect on energy transfer from the main lobe to the sidelobes of the acoustic field: that is, the aberrations make the total sidelobe level increase. This effect makes the ultrasound image poor when imaging heterogeneous organs. This study performs an analysis of the focal-field quality as a function of time/phase screen z position and time/phase screen correlation length. It establishes some rules of thumb which indicate when the focal-field sidelobe energy is at its highest. It also introduces a simple screen-scaling model which is useful as long as the screen position is not closer to the focus than a certain limit distance. The scaling model allows the real screen at a depth z=zscreen to be treated as a scaled screen at the position z=ztransd. 2D sound fields after 3D propagation from the annular arrays to the focal plane have been simulated using an angular spectrum method. The aberrators are represented by amplitude and phase/time screens.

  20. Disentangling Redshift-Space Distortions and Nonlinear Bias using the 2D Power Spectrum

    SciTech Connect

    Jennings, Elise; Wechsler, Risa H.

    2015-08-07

    We present the nonlinear 2D galaxy power spectrum, P(k, µ), in redshift space, measured from the Dark Sky simulations, using galaxy catalogs constructed with both halo occupation distribution and subhalo abundance matching methods, chosen to represent an intermediate redshift sample of luminous red galaxies. We find that the information content in individual µ (cosine of the angle to the line of sight) bins is substantially richer then multipole moments, and show that this can be used to isolate the impact of nonlinear growth and redshift space distortion (RSD) effects. Using the µ < 0.2 simulation data, which we show is not impacted by RSD effects, we can successfully measure the nonlinear bias to an accuracy of ~ 5% at k < 0.6hMpc-1 . This use of individual µ bins to extract the nonlinear bias successfully removes a large parameter degeneracy when constraining the linear growth rate of structure. We carry out a joint parameter estimation, using the low µ simulation data to constrain the nonlinear bias, and µ > 0.2 to constrain the growth rate and show that f can be constrained to ~ 26(22)% to a kmax < 0.4(0.6)hMpc-1 from clustering alone using a simple dispersion model, for a range of galaxy models. Our analysis of individual µ bins also reveals interesting physical effects which arise simply from different methods of populating halos with galaxies. We also find a prominent turnaround scale, at which RSD damping effects are greater then the nonlinear growth, which differs not only for each µ bin but also for each galaxy model. These features may provide unique signatures which could be used to shed light on the galaxy–dark matter connection. Furthermore, the idea of separating nonlinear growth and RSD effects making use of the full information in the 2D galaxy power spectrum yields significant improvements in constraining cosmological parameters and may be a promising probe of galaxy formation models.

  1. Disentangling Redshift-Space Distortions and Nonlinear Bias using the 2D Power Spectrum

    DOE PAGES

    Jennings, Elise; Wechsler, Risa H.

    2015-08-07

    We present the nonlinear 2D galaxy power spectrum, P(k, µ), in redshift space, measured from the Dark Sky simulations, using galaxy catalogs constructed with both halo occupation distribution and subhalo abundance matching methods, chosen to represent an intermediate redshift sample of luminous red galaxies. We find that the information content in individual µ (cosine of the angle to the line of sight) bins is substantially richer then multipole moments, and show that this can be used to isolate the impact of nonlinear growth and redshift space distortion (RSD) effects. Using the µ < 0.2 simulation data, which we show ismore » not impacted by RSD effects, we can successfully measure the nonlinear bias to an accuracy of ~ 5% at k < 0.6hMpc-1 . This use of individual µ bins to extract the nonlinear bias successfully removes a large parameter degeneracy when constraining the linear growth rate of structure. We carry out a joint parameter estimation, using the low µ simulation data to constrain the nonlinear bias, and µ > 0.2 to constrain the growth rate and show that f can be constrained to ~ 26(22)% to a kmax < 0.4(0.6)hMpc-1 from clustering alone using a simple dispersion model, for a range of galaxy models. Our analysis of individual µ bins also reveals interesting physical effects which arise simply from different methods of populating halos with galaxies. We also find a prominent turnaround scale, at which RSD damping effects are greater then the nonlinear growth, which differs not only for each µ bin but also for each galaxy model. These features may provide unique signatures which could be used to shed light on the galaxy–dark matter connection. Furthermore, the idea of separating nonlinear growth and RSD effects making use of the full information in the 2D galaxy power spectrum yields significant improvements in constraining cosmological parameters and may be a promising probe of galaxy formation models.« less

  2. Energy spectrum of a 2D Dirac oscillator in the presence of a constant magnetic field and an antidot potential

    NASA Astrophysics Data System (ADS)

    Akcay, Huseyin; Sever, Ramazan

    2016-07-01

    We investigate the energy spectrum and the corresponding eigenfunctions of a 2D Dirac oscillator confined by an antidot potential in the presence of a magnetic field and Aharonov-Bohm flux field. Analytical solutions are obtained and compared with the results of the Schrödinger equation found in the literature. Further, the dependence of the spectrum on the magnetic quantum number and on the repulsive potential is discussed.

  3. A comparison of 2D and 3D digital image correlation for a membrane under inflation

    PubMed Central

    Murienne, Barbara J.; Nguyen, Thao D.

    2015-01-01

    Three-dimensional (3D) digital image correlation (DIC) is becoming widely used to characterize the behavior of structures undergoing 3D deformations. However, the use of 3D-DIC can be challenging under certain conditions, such as high magnification, and therefore small depth of field, or a highly controlled environment with limited access for two-angled cameras. The purpose of this study is to compare 2D-DIC and 3D-DIC for the same inflation experiment and evaluate whether 2D-DIC can be used when conditions discourage the use of a stereo-vision system. A latex membrane was inflated vertically to 5.41 kPa (reference pressure), then to 7.87 kPa (deformed pressure). A two-camera stereo-vision system acquired top-down images of the membrane, while a single camera system simultaneously recorded images of the membrane in profile. 2D-DIC and 3D-DIC were used to calculate horizontal (in the membrane plane) and vertical (out of the membrane plane) displacements, and meridional strain. Under static conditions, the baseline uncertainty in horizontal displacement and strain were smaller for 3D-DIC than 2D-DIC. However, the opposite was observed for the vertical displacement, for which 2D-DIC had a smaller baseline uncertainty. The baseline absolute error in vertical displacement and strain were similar for both DIC methods, but it was larger for 2D-DIC than 3D-DIC for the horizontal displacement. Under inflation, the variability in the measurements were larger than under static conditions for both DIC methods. 2D-DIC showed a smaller variability in displacements than 3D-DIC, especially for the vertical displacement, but a similar strain uncertainty. The absolute difference in the average displacements and strain between 3D-DIC and 2D-DIC were in the range of the 3D-DIC variability. Those findings suggest that 2D-DIC might be used as an alternative to 3D-DIC to study the inflation response of materials under certain conditions. PMID:26543296

  4. A comparison of 2D and 3D digital image correlation for a membrane under inflation.

    PubMed

    Murienne, Barbara J; Nguyen, Thao D

    2016-02-01

    Three-dimensional (3D) digital image correlation (DIC) is becoming widely used to characterize the behavior of structures undergoing 3D deformations. However, the use of 3D-DIC can be challenging under certain conditions, such as high magnification, and therefore small depth of field, or a highly controlled environment with limited access for two-angled cameras. The purpose of this study is to compare 2D-DIC and 3D-DIC for the same inflation experiment and evaluate whether 2D-DIC can be used when conditions discourage the use of a stereo-vision system. A latex membrane was inflated vertically to 5.41 kPa (reference pressure), then to 7.87 kPa (deformed pressure). A two-camera stereo-vision system acquired top-down images of the membrane, while a single camera system simultaneously recorded images of the membrane in profile. 2D-DIC and 3D-DIC were used to calculate horizontal (in the membrane plane) and vertical (out of the membrane plane) displacements, and meridional strain. Under static conditions, the baseline uncertainty in horizontal displacement and strain were smaller for 3D-DIC than 2D-DIC. However, the opposite was observed for the vertical displacement, for which 2D-DIC had a smaller baseline uncertainty. The baseline absolute error in vertical displacement and strain were similar for both DIC methods, but it was larger for 2D-DIC than 3D-DIC for the horizontal displacement. Under inflation, the variability in the measurements were larger than under static conditions for both DIC methods. 2D-DIC showed a smaller variability in displacements than 3D-DIC, especially for the vertical displacement, but a similar strain uncertainty. The absolute difference in the average displacements and strain between 3D-DIC and 2D-DIC were in the range of the 3D-DIC variability. Those findings suggest that 2D-DIC might be used as an alternative to 3D-DIC to study the inflation response of materials under certain conditions.

  5. A comparison of 2D and 3D digital image correlation for a membrane under inflation

    NASA Astrophysics Data System (ADS)

    Murienne, Barbara J.; Nguyen, Thao D.

    2016-02-01

    Three-dimensional (3D) digital image correlation (DIC) is becoming widely used to characterize the behavior of structures undergoing 3D deformations. However, the use of 3D-DIC can be challenging under certain conditions, such as high magnification, and therefore small depth of field, or a highly controlled environment with limited access for two-angled cameras. The purpose of this study is to compare 2D-DIC and 3D-DIC for the same inflation experiment and evaluate whether 2D-DIC can be used when conditions discourage the use of a stereo-vision system. A latex membrane was inflated vertically to 5.41 kPa (reference pressure), then to 7.87 kPa (deformed pressure). A two-camera stereo-vision system acquired top-down images of the membrane, while a single camera system simultaneously recorded images of the membrane in profile. 2D-DIC and 3D-DIC were used to calculate horizontal (in the membrane plane) and vertical (out of the membrane plane) displacements, and meridional strain. Under static conditions, the baseline uncertainty in horizontal displacement and strain were smaller for 3D-DIC than 2D-DIC. However, the opposite was observed for the vertical displacement, for which 2D-DIC had a smaller baseline uncertainty. The baseline absolute error in vertical displacement and strain were similar for both DIC methods, but it was larger for 2D-DIC than 3D-DIC for the horizontal displacement. Under inflation, the variability in the measurements were larger than under static conditions for both DIC methods. 2D-DIC showed a smaller variability in displacements than 3D-DIC, especially for the vertical displacement, but a similar strain uncertainty. The absolute difference in the average displacements and strain between 3D-DIC and 2D-DIC were in the range of the 3D-DIC variability. Those findings suggest that 2D-DIC might be used as an alternative to 3D-DIC to study the inflation response of materials under certain conditions.

  6. Automatic angle measurement of a 2D object using optical correlator-neural networks hybrid system

    NASA Astrophysics Data System (ADS)

    Manivannan, N.; Neil, M. A. A.

    2011-04-01

    In this paper a novel method is proposed and demonstrated for automatic rotation angle measurement of a 2D object using a hybrid architecture, consisting of a 4f optical correlator with a binary phase only multiplexed matched filter and a single layer neural network. The hybrid set-up can be considered as a two-layer perceptron-like neural network; an optical correlator is the first layer and the standard single layer neural network is the second layer. The training scheme used to train the hybrid architecture is a combination of a Direct Binary Search algorithm, to train the optical correlator, and an Error Back Propagation algorithm, to train the neural network. The aim is to perform the major information processing by the optical correlator with a small additional processing by the neural network stage. This allows the system to be used for real-time applications as optics has the inherent ability to process information in a parallel manner at high speed. The neural network stage gives an extra dimension of freedom so that complicated tasks like automatic rotation angle measurement can be achieved. Results of both computer simulation and experimental set-up are presented for rotation angle measurement of an English alphabetic character as a 2D object. The experimental set-up consists of a real optical correlator using two spatial light modulators for both input and frequency plane representations and a PC based model of a single layer network.

  7. Face recognition based on the band fusion of generalized phase spectrum of 2D-FrFT

    NASA Astrophysics Data System (ADS)

    Wang, Xu; Qi, Lin; Tie, Yun; Chen, Enqing; Sun, Huijing

    2017-02-01

    In this paper, we propose a novel feature extraction method for face recognition based on two dimensional fractional Fourier transform (2D-FrFT). First, we extract the phase information of facial image in 2D-FrFT, which is called the generalized phase spectra (GPS). Then, we present an improved two-dimensional separability judgment (I2DSJ) to select appropriate order parameters for discrete fractional Fourier transform. Finally, multiple orders' generalized phase spectrum bands (MGPSB) fusion is proposed. In order to make full use of the discriminative information from different orders for face recognition, the proposed approach merges different orders' generalized phase spectra (GPS) of 2D-FrFT. The proposed method is no need to construct the subspace through the feature extraction methods and has less computation cost. Experimental results on the public face databases demonstrate that our method outperforms the representative methods.

  8. Evidence for a New Intermediate Phase in a Strongly Correlated 2D System near Wigner Crystallization

    NASA Astrophysics Data System (ADS)

    Gao, Xuan; Qiu, Richard; Goble, Nicholas; Serafin, Alex; Yin, Liang; Xia, Jian-Sheng; Sullivan, Neil; Pfeiffer, Loren; West, Ken

    How the two dimensional (2D) quantum Wigner crystal (WC) transforms into the metallic liquid phase remains an outstanding problem in physics. In theories considering the 2D WC to liquid transition in the clean limit, it was suggested that a number of intermediate phases might exist. We have studied the transformation between the metallic fluid phase and the low magnetic field reentrant insulating phase (RIP) which was interpreted as due to the WC [Qiu et al., PRL 108, 106404 (2012)], in a strongly correlated 2D hole system in GaAs quantum well with large interaction parameter rs (~20-30) and high mobility. Instead of a sharp transition, we found that increasing density (or lowering rs) drives the RIP into a state where the incipient RIP coexists with Fermi liquid. This apparent mixture phase intermediate between Fermi liquid and WC also exhibits a non-trivial temperature dependent resistivity behavior which can be qualitatively understood by the reversed melting of WC in the mixture, in analogy to the Pomeranchuk effect in the solid-liquid mixture of Helium-3. X.G. thanks NSF (DMR-0906415) for supporting work at CWRU. Experiments at the NHMFL High B/T Facility were supported by NSF Grant 0654118 and the State of Florida. L.P. thanks the Gordon and Betty Moore Foundation and NSF MRSEC (DMR-0819860) for support.

  9. Probing Spatio-Temporal Correlation in Complex Aqueous Systems through 2D-IR Spectroscopy

    NASA Astrophysics Data System (ADS)

    Bagchi, Biman; Biswas, Rajib; Samanta, Tuhin; Ghosh, Rikhia; Roy, Susmita

    2015-03-01

    Heterogeneity is ubiquitous in aqueous solutions, e.g., in protein and DNA solutions, micelles and reverse micelles, density fluctuations during phase transitions (e,g., water to ice). Origin of heterogeneity can be diverse, sometimes stimulated by external biomolecular subsystems (proteins, DNA, lipids), nanoscopic materials etc, but may also be intrinsic to the thermodynamic nature of the aqueous solution itself. The altered dynamics of water in presence of such diverse surfaces have attracted considerable attention in recent years. However, efficiently capturing the length and timescale of heterogeneous dynamics of water is indeed a challenging task. Recent development of two dimensional infra-red (2D-IR) allows us to estimate length and time scales of such dynamics fairly accurately. In this work, we present a series of interesting studies employing two dimensional infra-red spectroscopy (2D-IR) to investigate (i) dynamics of water inside reverse micelles of varying sizes, (ii) supercritical water near the Widom line that is known to exhibit pronounced density fluctuation and calculate. The respective studies reveal a number of interesting facts. Spatio-temporal correlation of water dynamics with varying size of reverse micelles is well captured through the spectral diffusion of corresponding 2D-IR spectra. In case of supercritical water also, we observe strong signature of dynamic heterogeneity from the elongated nature of the spectra.

  10. Determination of size and sign of hetero-nuclear coupling constants from 2D 19F-13C correlation spectra

    NASA Astrophysics Data System (ADS)

    Ampt, Kirsten A. M.; Aspers, Ruud L. E. G.; Dvortsak, Peter; van der Werf, Ramon M.; Wijmenga, Sybren S.; Jaeger, Martin

    2012-02-01

    Fluorinated organic compounds have become increasingly important within the polymer and the pharmaceutical industry as well as for clinical applications. For the structural elucidation of such compounds, NMR experiments with fluorine detection are of great value due to the favorable NMR properties of the fluorine nucleus. For the investigation of three fluorinated compounds, triple resonance 2D HSQC and HMBC experiments were adopted to fluorine detection with carbon and/or proton decoupling to yield F-C, F-C{H}, F-C{Cacq} and F-C{H,Cacq} variants. Analysis of E.COSY type cross-peak patterns in the F-C correlation spectra led, apart from the chemical shift assignments, to determination of size and signs of the JCH, JCF, and JHF coupling constants. In addition, the fully coupled F-C HMQC spectrum of steroid 1 was interpreted in terms of E.COSY type patterns. This example shows how coupling constants due to different nuclei can be determined together with their relative signs from a single spectrum. The analysis of cross-peak patterns, as presented here, not only provides relatively straightforward routes to the determination of size and sign of hetero-nuclear J-couplings in fluorinated compounds, it also provides new and easy ways for the determination of residual dipolar couplings and thus for structure elucidation. The examples and results presented in this study may contribute to a better interpretation and understanding of various F-C correlation experiments and thereby stimulate their utilization.

  11. Optimized 2D array of thin silicon pillars for efficient antireflective coatings in the visible spectrum

    PubMed Central

    Proust, Julien; Fehrembach, Anne-Laure; Bedu, Frédéric; Ozerov, Igor; Bonod, Nicolas

    2016-01-01

    Light reflection occuring at the surface of silicon wafers is drastically diminished by etching square pillars of height 110 nm and width 140 nm separated by a 100 nm gap distance in a square lattice. The design of the nanostructure is optimized to widen the spectral tolerance of the antireflective coatings over the visible spectrum for both fundamental polarizations. Angle and polarized resolved optical measurements report a light reflection remaining under 5% when averaged in the visible spectrum for both polarizations in a wide angular range. Light reflection remains almost insensitive to the light polarization even in oblique incidence. PMID:27109643

  12. Finger bone immaturity and 2D:4D ratio measurement error in the assessment of the hyperandrogenic hypothesis for the etiology of autism spectrum disorders.

    PubMed

    Bloom, Michael S; Houston, Allison S; Mills, James L; Molloy, Cynthia A; Hediger, Mary L

    2010-06-01

    Emerging hypotheses suggest a causal role for prenatal androgen exposure in some cases of autism spectrum disorders (ASD). The ratios of the lengths of the bones of the 2nd to the 4th digit (2D:4D) are purported to be markers for prenatal androgen exposure and to be established early in gestation. Elongation of the 4th digit in response to testosterone is said to reduce 2D:4D in males versus females. We examined the ratios of bones from the left hand radiographs of 75 boys and 6 girls 4-8 years of age, diagnosed with ASD, to evaluate digit ratio as a marker for gestational androgen exposure. Contrary to our expectations, girls had reduced 2D:4D compared to boys but the difference was not significant (Cohen's D 0.51-0.66, P>0.05). The limited sample size for this study and the absence of a referent group precluded providing robust estimates for girls and identifying possible statistical differences between the sexes. Tanner-Whitehouse 3 (TW3) rating of finger bone growth suggested relative immaturity of the 4th relative to the 2nd digits. Positive correlations were detected for 2D:4D ratios, body mass index (r=0.23, P=0.039), chronologic age (r=0.35, P=0.001), and skeletal age (r=0.42, P<0.0001). The TW3 ratings and associations between 2D:4D ratios and indicators of growth suggest that digits develop at different rates. This asynchronous development may produce differences in 2D:4D over time which could lead to erroneous interpretation of androgen exposure in utero among young ASD children.

  13. The 2dF Galaxy Redshift Survey: power-spectrum analysis of the final data set and cosmological implications

    NASA Astrophysics Data System (ADS)

    Cole, Shaun; Percival, Will J.; Peacock, John A.; Norberg, Peder; Baugh, Carlton M.; Frenk, Carlos S.; Baldry, Ivan; Bland-Hawthorn, Joss; Bridges, Terry; Cannon, Russell; Colless, Matthew; Collins, Chris; Couch, Warrick; Cross, Nicholas J. G.; Dalton, Gavin; Eke, Vincent R.; De Propris, Roberto; Driver, Simon P.; Efstathiou, George; Ellis, Richard S.; Glazebrook, Karl; Jackson, Carole; Jenkins, Adrian; Lahav, Ofer; Lewis, Ian; Lumsden, Stuart; Maddox, Steve; Madgwick, Darren; Peterson, Bruce A.; Sutherland, Will; Taylor, Keith

    2005-09-01

    We present a power-spectrum analysis of the final 2dF Galaxy Redshift Survey (2dFGRS), employing a direct Fourier method. The sample used comprises 221414 galaxies with measured redshifts. We investigate in detail the modelling of the sample selection, improving on previous treatments in a number of respects. A new angular mask is derived, based on revisions to the photometric calibration. The redshift selection function is determined by dividing the survey according to rest-frame colour, and deducing a self-consistent treatment of k-corrections and evolution for each population. The covariance matrix for the power-spectrum estimates is determined using two different approaches to the construction of mock surveys, which are used to demonstrate that the input cosmological model can be correctly recovered. We discuss in detail the possible differences between the galaxy and mass power spectra, and treat these using simulations, analytic models and a hybrid empirical approach. Based on these investigations, we are confident that the 2dFGRS power spectrum can be used to infer the matter content of the universe. On large scales, our estimated power spectrum shows evidence for the `baryon oscillations' that are predicted in cold dark matter (CDM) models. Fitting to a CDM model, assuming a primordial ns= 1 spectrum, h= 0.72 and negligible neutrino mass, the preferred parameters are Ωmh= 0.168 +/- 0.016 and a baryon fraction Ωb/Ωm= 0.185 +/- 0.046 (1σ errors). The value of Ωmh is 1σ lower than the 0.20 +/- 0.03 in our 2001 analysis of the partially complete 2dFGRS. This shift is largely due to the signal from the newly sampled regions of space, rather than the refinements in the treatment of observational selection. This analysis therefore implies a density significantly below the standard Ωm= 0.3: in combination with cosmic microwave background (CMB) data from the Wilkinson Microwave Anisotropy Probe (WMAP), we infer Ωm= 0.231 +/- 0.021.

  14. The infrared spectrum of the He–C{sub 2}D{sub 2} complex

    SciTech Connect

    Moazzen-Ahmadi, N.; McKellar, A. R. W.; Fernández, Berta; Farrelly, David

    2015-02-28

    Spectra of the helium-acetylene complex are elusive because this weakly bound system lies close to the free rotor limit. Previously, limited assignments of He–C{sub 2}D{sub 2} transitions in the R(0) region of the ν{sub 3} fundamental band (≈2440 cm{sup −1}) were published. Here, new He–C{sub 2}D{sub 2} infrared spectra of this band are obtained using a tunable optical parametric oscillator laser source to probe a pulsed supersonic slit jet expansion from a cooled nozzle, and the analysis is extended to the weaker and more difficult P(1) and R(1) regions. A term value approach is used to obtain a consistent set of “experimental” energy levels. These are compared directly with calculations using two recently reported ab initio intermolecular potential energy surfaces, which exhibit small but significant differences. Rovibrational energies for the He–C{sub 2}H{sub 2} complex are also calculated using both surfaces. A Coriolis model, useful for predicting spectral intensities, is used to interpret the energy level patterns, and a comparison with the isoelectronic complex He–CO is made.

  15. A 2D correlation Raman spectroscopy analysis of a human cataractous lens

    NASA Astrophysics Data System (ADS)

    Sacharz, Julia; Wesełucha-Birczyńska, Aleksandra; Paluszkiewicz, Czesława; Chaniecki, Piotr; Błażewicz, Marta

    2016-11-01

    This work is a continuation of our study of a cataractous human eye lens removed after phacoemulsification surgery. There are clear differences in the lens colors that allowed for distinguishing two opaque phases in the obtained biological material: the white- and yellow-phase. The Raman spectroscopy and 2D correlation spectroscopy method were used to trace a pathologically altered human cataract lens at a molecular level. Although the Raman spectra of these two phases are relatively similar, taking advantage of 2D correlation, and considering time as an external perturbation, the synchronous and asynchronous spectra were obtained showing completely different patterns. Prominent synchronous auto-peaks appear at 3340, 2920, 1736, 1665 and 1083 cm-1 for the white-, and at 2929 and 1670 cm-1 for the yellow phase. The white phase is characterized by intensive asynchronous peaks at -(2936, 3360), -(1650, 1674) and +(1620,1678). The modifications in the water contained in the white phase structure are ahead of the changes in the protein (CH3-groups), furthermore changes in β-conformation are asynchronous with respect to the α-structure. The yellow phase demonstrates asynchronous peaks: +(2857, 2928), +(1645,1673), +(1663, 1679), and +(1672,1707). These illustrate concomitant modifications in the β- and unordered conformation. Both forms of cataractous human eye lens, white- and yellow-phases, are degenerate forms of the eye lens proteins, both are arranged in a different way. The main differences are observed for the amide I, methyl, methylene and Osbnd H vibrational band region. The effect of Asp, Glu and Tyr amino acids in cataractous lens transformations was observed.

  16. In-die photomask registration and overlay metrology with PROVE using 2D correlation methods

    NASA Astrophysics Data System (ADS)

    Seidel, D.; Arnz, M.; Beyer, D.

    2011-11-01

    According to the ITRS roadmap, semiconductor industry drives the 193nm lithography to its limits, using techniques like double exposure, double patterning, mask-source optimization and inverse lithography. For photomask metrology this translates to full in-die measurement capability for registration and critical dimension together with challenging specifications for repeatability and accuracy. Especially, overlay becomes more and more critical and must be ensured on every die. For this, Carl Zeiss SMS has developed the next generation photomask registration and overlay metrology tool PROVE® which serves the 32nm node and below and which is already well established in the market. PROVE® features highly stable hardware components for the stage and environmental control. To ensure in-die measurement capability, sophisticated image analysis methods based on 2D correlations have been developed. In this paper we demonstrate the in-die capability of PROVE® and present corresponding measurement results for shortterm and long-term measurements as well as the attainable accuracy for feature sizes down to 85nm using different illumination modes and mask types. Standard measurement methods based on threshold criteria are compared with the new 2D correlation methods to demonstrate the performance gain of the latter. In addition, mask-to-mask overlay results of typical box-in-frame structures down to 200nm feature size are presented. It is shown, that from overlay measurements a reproducibility budget can be derived that takes into account stage, image analysis and global effects like mask loading and environmental control. The parts of the budget are quantified from measurement results to identify critical error contributions and to focus on the corresponding improvement strategies.

  17. SENSITIVITY OF COSMIC-RAY PROTON SPECTRA TO THE LOW-WAVENUMBER BEHAVIOR OF THE 2D TURBULENCE POWER SPECTRUM

    SciTech Connect

    Engelbrecht, N. E.; Burger, R. A.

    2015-12-01

    In this study, a novel ab initio cosmic ray (CR) modulation code that solves a set of stochastic transport equations equivalent to the Parker transport equation, and that uses output from a turbulence transport code as input for the diffusion tensor, is introduced. This code is benchmarked with a previous approach to ab initio modulation. The sensitivity of computed galactic CR proton spectra at Earth to assumptions made as to the low-wavenumber behavior of the two-dimensional (2D) turbulence power spectrum is investigated using perpendicular mean free path expressions derived from two different scattering theories. Constraints on the low-wavenumber behavior of the 2D power spectrum are inferred from the qualitative comparison of computed CR spectra with spacecraft observations at Earth. Another key difference from previous studies is that observed and inferred CR intensity spectra at 73 AU are used as boundary spectra instead of the usual local interstellar spectrum. Furthermore, the results presented here provide a tentative explanation as to the reason behind the unusually high galactic proton intensity spectra observed in 2009 during the recent unusual solar minimum.

  18. Baryon acoustic oscillations in 2D: Modeling redshift-space power spectrum from perturbation theory

    SciTech Connect

    Taruya, Atsushi; Nishimichi, Takahiro; Saito, Shun

    2010-09-15

    We present an improved prescription for the matter power spectrum in redshift space taking proper account of both nonlinear gravitational clustering and redshift distortion, which are of particular importance for accurately modeling baryon acoustic oscillations (BAOs). Contrary to the models of redshift distortion phenomenologically introduced but frequently used in the literature, the new model includes the corrections arising from the nonlinear coupling between the density and velocity fields associated with two competitive effects of redshift distortion, i.e., Kaiser and Finger-of-God effects. Based on the improved treatment of perturbation theory for gravitational clustering, we compare our model predictions with the monopole and quadrupole power spectra of N-body simulations, and an excellent agreement is achieved over the scales of BAOs. Potential impacts on constraining dark energy and modified gravity from the redshift-space power spectrum are also investigated based on the Fisher-matrix formalism, particularly focusing on the measurements of the Hubble parameter, angular diameter distance, and growth rate for structure formation. We find that the existing phenomenological models of redshift distortion produce a systematic error on measurements of the angular diameter distance and Hubble parameter by 1%-2%, and the growth-rate parameter by {approx}5%, which would become non-negligible for future galaxy surveys. Correctly modeling redshift distortion is thus essential, and the new prescription for the redshift-space power spectrum including the nonlinear corrections can be used as an accurate theoretical template for anisotropic BAOs.

  19. 2D versus 3D cross-correlation-based radial and circumferential strain estimation using multiplane 2D ultrafast ultrasound in a 3D atherosclerotic carotid artery model.

    PubMed

    Fekkes, Stein; Swillens, Abigail E S; Hansen, Hendrik H G; Saris, Anne E C M; Nillesen, Maartje M; Iannaccone, Francesco; Segers, Patrick; de Korte, Chris L

    2016-08-25

    Three-dimensional strain estimation might improve the detection and localization of high strain regions in the carotid artery for identification of vulnerable plaques. This study compares 2D vs. 3D displacement estimation in terms of radial and circumferential strain using simulated ultrasound images of a patient specific 3D atherosclerotic carotid artery model at the bifurcation embedded in surrounding tissue generated with ABAQUS software. Global longitudinal motion was superimposed to the model based on literature data. A Philips L11-3 linear array transducer was simulated which transmitted plane waves at 3 alternating angles at a pulse repetition rate of 10 kHz. Inter-frame radiofrequency ultrasound data were simulated in Field II for 191 equally spaced longitudinal positions of the internal carotid artery. Accumulated radial and circumferential displacements were estimated using tracking of the inter-frame displacements estimated by a two-step normalized cross-correlation method and displacement compounding. Least squares strain estimation was performed to determine accumulated radial and circumferential strain. The performance of the 2D and 3D method was compared by calculating the root-mean-squared error of the estimated strains with respect to the reference strains obtained from the model. More accurate strain images were obtained using the 3D displacement estimation for the entire cardiac cycle. The 3D technique clearly outperformed the 2D technique in phases with high inter-frame longitudinal motion. In fact the large inter-frame longitudinal motion rendered it impossible to accurately track the tissue and cumulate strains over the entire cardiac cycle with the 2D technique.

  20. 2-D Versus 3-D Cross-Correlation-Based Radial and Circumferential Strain Estimation Using Multiplane 2-D Ultrafast Ultrasound in a 3-D Atherosclerotic Carotid Artery Model.

    PubMed

    Fekkes, Stein; Swillens, Abigail E S; Hansen, Hendrik H G; Saris, Anne E C M; Nillesen, Maartje M; Iannaccone, Francesco; Segers, Patrick; de Korte, Chris L

    2016-10-01

    Three-dimensional (3-D) strain estimation might improve the detection and localization of high strain regions in the carotid artery (CA) for identification of vulnerable plaques. This paper compares 2-D versus 3-D displacement estimation in terms of radial and circumferential strain using simulated ultrasound (US) images of a patient-specific 3-D atherosclerotic CA model at the bifurcation embedded in surrounding tissue generated with ABAQUS software. Global longitudinal motion was superimposed to the model based on the literature data. A Philips L11-3 linear array transducer was simulated, which transmitted plane waves at three alternating angles at a pulse repetition rate of 10 kHz. Interframe (IF) radio-frequency US data were simulated in Field II for 191 equally spaced longitudinal positions of the internal CA. Accumulated radial and circumferential displacements were estimated using tracking of the IF displacements estimated by a two-step normalized cross-correlation method and displacement compounding. Least-squares strain estimation was performed to determine accumulated radial and circumferential strain. The performance of the 2-D and 3-D methods was compared by calculating the root-mean-squared error of the estimated strains with respect to the reference strains obtained from the model. More accurate strain images were obtained using the 3-D displacement estimation for the entire cardiac cycle. The 3-D technique clearly outperformed the 2-D technique in phases with high IF longitudinal motion. In fact, the large IF longitudinal motion rendered it impossible to accurately track the tissue and cumulate strains over the entire cardiac cycle with the 2-D technique.

  1. Spatial Correlation of Rain Drop Size Distribution from Polarimetric Radar and 2D-Video Disdrometers

    NASA Technical Reports Server (NTRS)

    Thurai, Merhala; Bringi, Viswanathan; Gatlin, Patrick N.; Wingo, Matt; Petersen, Walter Arthur; Carey, Lawrence D.

    2011-01-01

    Spatial correlations of two of the main rain drop-size distribution (DSD) parameters - namely the median-volume diameter (Do) and the normalized intercept parameter (Nw) - as well as rainfall rate (R) are determined from polarimetric radar measurements, with added information from 2D video disdrometer (2DVD) data. Two cases have been considered, (i) a widespread, long-duration rain event in Huntsville, Alabama, and (ii) an event with localized intense rain-cells within a convection line which occurred during the MC3E campaign. For the first case, data from a C-band polarimetric radar (ARMOR) were utilized, with two 2DVDs acting as ground-truth , both being located at the same site 15 km from the radar. The radar was operated in a special near-dwelling mode over the 2DVDs. In the second case, data from an S-band polarimetric radar (NPOL) data were utilized, with at least five 2DVDs located between 20 and 30 km from the radar. In both rain event cases, comparisons of Do, log10(Nw) and R were made between radar derived estimates and 2DVD-based measurements, and were found to be in good agreement, and in both cases, the radar data were subsequently used to determine the spatial correlations For the first case, the spatial decorrelation distance was found to be smallest for R (4.5 km), and largest fo Do (8.2 km). For log10(Nw) it was 7.2 km (Fig. 1). For the second case, the corresponding decorrelation distances were somewhat smaller but had a directional dependence. In Fig. 2, we show an example of Do comparisons between NPOL based estimates and 1-minute DSD based estimates from one of the five 2DVDs.

  2. Abnormal expression levels of sMICA and NKG2D are correlated with poor prognosis in pancreatic cancer

    PubMed Central

    Chen, Jiong; Xu, Hong; Zhu, Xing-Xing

    2016-01-01

    Soluble major histocompatibility complex class I-related chain A molecules (sMICA) and natural-killer group 2 member D (NKG2D) not only correlate with tumorigenesis and progression, but also with tumor invasion and metastasis. In this study, we used immunohistochemistry to investigate the correlation and prognostic significance of the differential expression of sMICA and NKG2D in pancreatic carcinoma and paracarcinoma tissues from 70 patients with pancreatic carcinomas. The results showed that sMICA expression was significantly (P<0.05) higher in tumor tissues (67.1%) than that in adjacent nontumor tissues (31.4%), whereas NKG2D expression was significantly (P<0.001) lower in tumor tissues (32.9%) than that in adjacent nontumor tissues (60.0%). Spearman’s rank correlation test showed a negative correlation between the expression of sMICA and that of NKG2D (r=−0.676, P<0.001). Kaplan–Meier survival analysis showed that a high sMICA expression was significantly correlated with decreased disease-free survival (DFS) (P<0.001) and overall survival (OS) (P<0.001), while a high NKG2D expression was significantly associated with increased DFS (P=0.001) and OS (P=0.001) of the patients. Multivariate analysis showed that a high sMICA expression was an independent predictive factor for poor DFS (P<0.001) and OS (P=0.012); but low NKG2D expression was not an independent prognostic factor for poor DFS (P=0.238) and OS (P=0.574). In conclusion, our findings suggest that the expression levels of sMICA and NKG2D are abnormal and negatively correlated with one another in pancreatic carcinoma tissues; they may be considered as valuable biomarkers for the prognosis of pancreatic carcinoma. PMID:26730197

  3. Detection of CYP2D6 polymorphism using Luminex xTAG technology in autism spectrum disorder: CYP2D6 activity score and its association with risperidone levels.

    PubMed

    Vanwong, Natchaya; Ngamsamut, Nattawat; Hongkaew, Yaowaluck; Nuntamool, Nopphadol; Puangpetch, Apichaya; Chamnanphon, Montri; Sinrachatanant, Ananya; Limsila, Penkhae; Sukasem, Chonlaphat

    2016-04-01

    CYP2D6 is involved in the biotransformation of a large number of drugs, including risperidone. This study was designed to detect CYP2D6 polymorphisms with a Luminex assay, including assessment the relationship of CYP2D6 polymorphisms and risperidone plasma concentration in autism spectrum disorder children (ASD) treated with risperidone. All 84 ASD patients included in this study had been receiving risperidone at least for 1 month. The CYP2D6 genotypes were determined by Luminex assay. Plasma concentrations of risperidone and 9-hydroxyrisperidone were measured using LC/MS/MS. Among the 84 patients, there were 46 (55.42%) classified as EM, 33 (39.76%) as IM, and 4(4.82%) as UM. The plasma concentration of risperidone and risperidone/9-hydroxyrisperidone ratio in the patients were significant differences among the CYP2D6 predicted phenotype group (P = 0.001 and P < 0.0001 respectively). Moreover, the plasma concentration of risperidone and risperidone/9-hydroxyrisperidone ratio in the patients with CYP2D6 activity score 0.5 were significantly higher than those with the CYP2D6 activity score 2.0 (P = 0.004 and P = 0.002 respectively). These findings suggested that the determination of the accurate CYP2D6 genotype-predicted phenotype is essential in the clinical setting and individualization of drug therapy. The use of the Luminex assay for detection of CYP2D6 polymorphisms could help us more accurately identify an individual's CYP2D6 phenotype.

  4. Enhancement of long-range correlations in a 2D vortex lattice by an incommensurate 1D disorder potential

    NASA Astrophysics Data System (ADS)

    Guillamon, I.; Vieira, S.; Suderow, H.; Cordoba, R.; Sese, J.; de Teresa, J. M.; Ibarra, R.

    In two dimensional (2D) systems, theory has proposed that random disorder destroys long range correlations driving a transition to a glassy state. Here, I will discuss new insights into this issue obtained through the direct visualization of the critical behaviour of a 2D superconducting vortex lattice formed in a thin film with a smooth 1D thickness modulation. Using scanning tunneling microscopy at 0.1K, we have tracked the modification in the 2D vortex arrangements induced by the 1D thickness modulation while increasing the vortex density by three orders of magnitude. Upon increasing the field, we observed a two-step order-disorder transition in the 2D vortex lattice mediated by the appearance of dislocations and disclinations and accompanied by an increase in the local vortex density fluctuations. Through a detailed analysis of correlation functions, we find that the transition is driven by the incommensurate 1D thickness modulation. We calculate the critical points and exponents and find that they are well above theoretical expectation for random disorder. Our results show that long range 1D correlations in random potentials enhance the stability range of the ordered phase in a 2D vortex lattice. Work supported by Spanish MINECO, CIG Marie Curie Grant, Axa Research Fund and FBBVA.

  5. Evaluation on intrinsic quality of licorice influenced by environmental factors by using FTIR combined with 2D-IR correlation spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhou, Ying-qun; Yu, Hua; Zhang, Yan-ling; Sun, Su-qin; Chen, Shi-lin; Zhao, Run-huai; Zhou, Qun; Noda, Isao

    2010-06-01

    To evaluate the intrinsic quality of licorice influenced by environmental factors, the spectral comparison of licorice from two typical ecological habitats was conducted by using FTIR and 2D-IR correlation spectroscopy. There were differences in the peak intensities of 1155, 1076 and 1048 cm -1 of FTIR profiles. The difference was amplified by the second derivative spectrum for the peak intensities at 1370, 1365 and 1317 cm -1 and the peak shape in 958-920 cm -1 and 1050-988 cm -1. The synchronous 2D-IR spectra within the range of 860-1300 cm -1 were classified into type I and type II and their frequency in the two groups was noticeably different. Although the chemical compounds of licorice samples from two areas were generally similar, the contents of starch, calcium oxalate, and some chemical compounds containing alcohol hydroxyl group were different, indicating the influence of precipitation and temperature. This study demonstrates that the systematical analysis of FTIR, the second derivative spectrum and 2D-IR can effectively determine the differences in licorice samples from different ecological habitats.

  6. Synchronous two-dimensional MIR correlation spectroscopy (2D-COS) as a novel method for screening smoke tainted wine.

    PubMed

    Fudge, Anthea L; Wilkinson, Kerry L; Ristic, Renata; Cozzolino, Daniel

    2013-08-15

    In this study, two-dimensional correlation spectroscopy (2D-COS) combined with mid-infrared (MIR) spectroscopy was evaluated as a novel technique for the identification of spectral regions associated with smoke-affected wine, for the purpose of screening taint arising from grapevine exposure to smoke. Smoke-affected wines obtained from experimental and industry sources were analysed using MIR spectroscopy and chemometrics, and calibration models developed. 2D-COS analysis was used to generate synchronous data maps for red and white cask wines spiked with guaiacol, a marker of smoke taint. Correlations were observed at wavelengths that could be attributable to aromatic C-C stretching, i.e., between 1400 and 1500 cm(-1), indicative of volatile phenols. These results demonstrate the potential of 2D-COS as a rapid, high-throughput technique for the preliminary screening of smoke tainted wine.

  7. Spectrum simulation of rough and nanostructured targets from their 2D and 3D image by Monte Carlo methods

    NASA Astrophysics Data System (ADS)

    Schiettekatte, François; Chicoine, Martin

    2016-03-01

    Corteo is a program that implements Monte Carlo (MC) method to simulate ion beam analysis (IBA) spectra of several techniques by following the ions trajectory until a sufficiently large fraction of them reach the detector to generate a spectrum. Hence, it fully accounts for effects such as multiple scattering (MS). Here, a version of Corteo is presented where the target can be a 2D or 3D image. This image can be derived from micrographs where the different compounds are identified, therefore bringing extra information into the solution of an IBA spectrum, and potentially significantly constraining the solution. The image intrinsically includes many details such as the actual surface or interfacial roughness, or actual nanostructures shape and distribution. This can for example lead to the unambiguous identification of structures stoichiometry in a layer, or at least to better constraints on their composition. Because MC computes in details the trajectory of the ions, it simulates accurately many of its aspects such as ions coming back into the target after leaving it (re-entry), as well as going through a variety of nanostructures shapes and orientations. We show how, for example, as the ions angle of incidence becomes shallower than the inclination distribution of a rough surface, this process tends to make the effective roughness smaller in a comparable 1D simulation (i.e. narrower thickness distribution in a comparable slab simulation). Also, in ordered nanostructures, target re-entry can lead to replications of a peak in a spectrum. In addition, bitmap description of the target can be used to simulate depth profiles such as those resulting from ion implantation, diffusion, and intermixing. Other improvements to Corteo include the possibility to interpolate the cross-section in angle-energy tables, and the generation of energy-depth maps.

  8. CC2D2A mutations in Meckel and Joubert syndromes indicate a genotype-phenotype correlation

    PubMed Central

    Mougou-Zerelli, Soumaya; Thomas, Sophie; Szenker, Emmanuelle; Audollent, Sophie; Elkhartoufi, Nadia; Babarit, Candice; Romano, Stéphane; Salomon, Rémi; Amiel, Jeanne; Esculpavit, Chantal; Gonzales, Marie; Escudier, Estelle; Leheup, Bruno; Loget, Philippe; Odent, Sylvie; Roume, Joëlle; Gérard, Marion; Delezoide, Anne-Lise; Khung, Suonavy; Patrier, Sophie; Cordier, Marie-Pierre; Bouvier, Raymonde; Martinovic, Jéléna; Gubler, Marie-Claire; Boddaert, Nathalie; Munnich, Arnold; Encha-Razavi, Férechté; Valente, Enza Maria; Saad, Ali; Saunier, Sophie; Vekemans, Michel; Attié-Bitach, Tania

    2009-01-01

    The Meckel syndrome (MKS) is a lethal fetal disorder characterized by diffuse renal cystic dysplasia, polydactyly, a brain malformation that is usually occipital encephalocele and/or vermian agenesis, with intrahepatic biliary duct proliferation. Joubert syndrome (JBS) is a viable neurological disorder with a characteristic “molar tooth sign” (MTS) on axial images reflecting cerebellar vermian hypoplasia/dysplasia. Both conditions are classified as ciliopathies with an autosomal recessive mode of inheritance. Allelism of MS and JBS has been reported for TMEM67/MKS3, CEP290/MKS4, and RPGRIP1L/MKS5. Recently, one homozygous splice mutation with a founder effect was reported in the CC2D2A gene in Finnish fetuses with MKS, defining the 6th locus for MKS. Shortly thereafter, CC2D2A mutations were reported in JBS also. The analysis of the CC2D2A gene in our series of MKS fetuses, identified 14 novel truncating mutations in 11 cases. These results confirm the involvement of CC2D2A in MKS and reveal a major contribution of CC2D2A to the disease. We also identified three missense CC2D2A mutations in two JBS cases. Therefore and in accordance with the data reported regarding RPGRIP1L, our results indicate phenotype-genotype correlations, as missense and presumably hypomorphic mutations lead to JBS while all null alleles lead to MKS. PMID:19777577

  9. [Identification and analysis of genuine and false Flos Rosae Rugosae by FTIR and 2D correlation IR spectroscopy].

    PubMed

    Cai, Fang; Sun, Su-qin; Yan, Wen-rong; Niu, Shi-jie; Li, Xian-en

    2009-09-01

    The genuine and false Flos Rosae Rugosae (Flos Rosae Chinensis and Flos Rosa multiflora) were examined in terms of their differences by using Fourier transform infrared spectroscopy (FTIR) combined with two-dimensional (2D) correlation IR spectroscopy. The three species were shown very similar in FTIR spectra. The peak of 1318 cm(-1) of genuine Flos Rosae Rugosae is not obvious but this peak could be found sharp in Flos Rosae Chinensis and Flos Rosa multiflora. Generally, the second derivative IR spectrum can clearly enhance the spectral resolution. Flos Rosae Rugosae and Flos rosae Chinensis have aromatic compounds distinct fingerprint characteristics at 1 617 and 1 618 cm(-1), respectively. Nevertheless, FlosRosa multiflora has the peak at 1612 cm(-1). There is a discrepancy of 5 to 6 cm(-1). FlosRosa multiflora has glucide's distinct fingerprint characteristics at 1 044 cm(-1), but Flos Rosae Rugosae and Flos Rosae Chinensis don't. The second derivative infrared spectra indicated different fingerprint characteristics. Three of them showed aromatic compounds with autopeaks at 1620, 1560 and 1460 cm(-1). Flos Rosae Chinensis and Flos Rosa multiflora have the shoulder peak at 1660 cm(-1). In the range of 850-1250 cm(-1), three of them are distinct different, Flos Rosae Rugosae has the strongest autopeak, Flos Rosae Chinensis has the feeble autopeak and Flos Rosa multiflora has no autopeak at 1050 cm(-1). In third-step identification, the different contents of aromatic compounds and glucide in Flos Rosae Rugosae, Flos Rosae Chinensis and Flos Rosa multiflora were revealed. It is proved that the method is fast and effective for distinguishing and analyzing genuine Flos Rosae Rugosae and false Flos Rosae Rugosae (Flos Rosae Chinensis and Flos Rosa multiflora).

  10. Modulating the vibronic correlation in 2D superconductor by electric field

    NASA Astrophysics Data System (ADS)

    Kazempour, Ali; Morshedloo, Toktam

    2017-04-01

    Superconductivity in the extreme two-dimensional atomic layers has been suffered because of the strong affection dimensionality confinement on electron-phonon binding. Here, using first-principles method, we study the effect of applied perpendicular and parallel electric field on the strength of phonon renormalization and electron-phonon coupling in bi-layer MgB2 as a known 2D superconductor. The changes of phonon frequency and line-width demonstrate that important E2 g optical modes are strongly sensitive to the applied parallel electric field which directs to sharp reduction of vibronic coupling. Whereas, we show that perpendicular electric field modulates the system to the strong-coupling superconductor and predict the enhancement of critical temperature Tc . Our study opens up the use of electric filed to probe and measure the variation amount of electron-phonon renormalization as a gauge in 2D superconductivity.

  11. Constant-time 2D and 3D through-bond correlation NMR spectroscopy of solids under 60 kHz MAS

    SciTech Connect

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy

    2016-01-21

    Establishing connectivity and proximity of nuclei is an important step in elucidating the structure and dynamics of molecules in solids using magic angle spinning (MAS) NMR spectroscopy. Although recent studies have successfully demonstrated the feasibility of proton-detected multidimensional solid-state NMR experiments under ultrafast-MAS frequencies and obtaining high-resolution spectral lines of protons, assignment of proton resonances is a major challenge. In this study, we first re-visit and demonstrate the feasibility of 2D constant-time uniform-sign cross-peak correlation (CTUC-COSY) NMR experiment on rigid solids under ultrafast-MAS conditions, where the sensitivity of the experiment is enhanced by the reduced spin-spin relaxation rate and the use of low radio-frequency power for heteronuclear decoupling during the evolution intervals of the pulse sequence. In addition, we experimentally demonstrate the performance of a proton-detected pulse sequence to obtain a 3D {sup 1}H/{sup 13}C/{sup 1}H chemical shift correlation spectrum by incorporating an additional cross-polarization period in the CTUC-COSY pulse sequence to enable proton chemical shift evolution and proton detection in the incrementable t{sub 1} and t{sub 3} periods, respectively. In addition to through-space and through-bond {sup 13}C/{sup 1}H and {sup 13}C/{sup 13}C chemical shift correlations, the 3D {sup 1}H/{sup 13}C/{sup 1}H experiment also provides a COSY-type {sup 1}H/{sup 1}H chemical shift correlation spectrum, where only the chemical shifts of those protons, which are bonded to two neighboring carbons, are correlated. By extracting 2D F1/F3 slices ({sup 1}H/{sup 1}H chemical shift correlation spectrum) at different {sup 13}C chemical shift frequencies from the 3D {sup 1}H/{sup 13}C/{sup 1}H spectrum, resonances of proton atoms located close to a specific carbon atom can be identified. Overall, the through-bond and through-space homonuclear/heteronuclear proximities determined from the

  12. Constant-time 2D and 3D through-bond correlation NMR spectroscopy of solids under 60 kHz MAS

    PubMed Central

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy

    2016-01-01

    Establishing connectivity and proximity of nuclei is an important step in elucidating the structure and dynamics of molecules in solids using magic angle spinning (MAS) NMR spectroscopy. Although recent studies have successfully demonstrated the feasibility of proton-detected multidimensional solid-state NMR experiments under ultrafast-MAS frequencies and obtaining high-resolution spectral lines of protons, assignment of proton resonances is a major challenge. In this study, we first re-visit and demonstrate the feasibility of 2D constant-time uniform-sign cross-peak correlation (CTUC-COSY) NMR experiment on rigid solids under ultrafast-MAS conditions, where the sensitivity of the experiment is enhanced by the reduced spin-spin relaxation rate and the use of low radio-frequency power for heteronuclear decoupling during the evolution intervals of the pulse sequence. In addition, we experimentally demonstrate the performance of a proton-detected pulse sequence to obtain a 3D 1H/13C/1H chemical shift correlation spectrum by incorporating an additional cross-polarization period in the CTUC-COSY pulse sequence to enable proton chemical shift evolution and proton detection in the incrementable t1 and t3 periods, respectively. In addition to through-space and through-bond 13C/1H and 13C/13C chemical shift correlations, the 3D 1H/13C/1H experiment also provides a COSY-type 1H/1H chemical shift correlation spectrum, where only the chemical shifts of those protons, which are bonded to two neighboring carbons, are correlated. By extracting 2D F1/F3 slices (1H/1H chemical shift correlation spectrum) at different 13C chemical shift frequencies from the 3D 1H/13C/1H spectrum, resonances of proton atoms located close to a specific carbon atom can be identified. Overall, the through-bond and through-space homonuclear/heteronuclear proximities determined from the 3D 1H/13C/1H experiment would be useful to study the structure and dynamics of a variety of chemical and biological

  13. Noise reduction methods applied to two-dimensional correlation spectroscopy (2D-COS) reveal complementary benefits of pre- and post-treatment.

    PubMed

    Foist, Rod B; Schulze, H Georg; Ivanov, Andre; Turner, Robin F B

    2011-05-01

    Two-dimensional correlation spectroscopy (2D-COS) is a powerful spectral analysis technique widely used in many fields of spectroscopy because it can reveal spectral information in complex systems that is not readily evident in the original spectral data alone. However, noise may severely distort the information and thus limit the technique's usefulness. Consequently, noise reduction is often performed before implementing 2D-COS. In general, this is implemented using one-dimensional (1D) methods applied to the individual input spectra, but, because 2D-COS is based on sets of successive spectra and produces 2D outputs, there is also scope for the utilization of 2D noise-reduction methods. Furthermore, 2D noise reduction can be applied either to the original set of spectra before performing 2D-COS ("pretreatment") or on the 2D-COS output ("post-treatment"). Very little work has been done on post-treatment; hence, the relative advantages of these two approaches are unclear. In this work we compare the noise-reduction performance on 2D-COS of pretreatment and post-treatment using 1D (wavelets) and 2D algorithms (wavelets, matrix maximum entropy). The 2D methods generally outperformed the 1D method in pretreatment noise reduction. 2D post-treatment in some cases was superior to pretreatment and, unexpectedly, also provided correlation coefficient maps that were similar to 2D correlation spectroscopy maps but with apparent better contrast.

  14. In vivo 1D and 2D correlation MR spectroscopy of the soleus muscle at 7T

    NASA Astrophysics Data System (ADS)

    Ramadan, Saadallah; Ratai, Eva-Maria; Wald, Lawrence L.; Mountford, Carolyn E.

    2010-05-01

    AimThis study aims to (1) undertake and analyse 1D and 2D MR correlation spectroscopy from human soleus muscle in vivo at 7T, and (2) determine T1 and T2 relaxation time constants at 7T field strength due to their importance in sequence design and spectral quantitation. MethodSix healthy, male volunteers were consented and scanned on a 7T whole-body scanner (Siemens AG, Erlangen, Germany). Experiments were undertaken using a 28 cm diameter detunable birdcage coil for signal excitation and an 8.5 cm diameter surface coil for signal reception. The relaxation time constants, T1 and T2 were recorded using a STEAM sequence, using the 'progressive saturation' method for the T1 and multiple echo times for T2. The 2D L-Correlated SpectroscopY (L-COSY) method was employed with 64 increments (0.4 ms increment size) and eight averages per scan, with a total time of 17 min. ResultsT1 and T2 values for the metabolites of interest were determined. The L-COSY spectra obtained from the soleus muscle provided information on lipid content and chemical structure not available, in vivo, at lower field strengths. All molecular fragments within multiple lipid compartments were chemically shifted by 0.20-0.26 ppm at this field strength. 1D and 2D L-COSY spectra were assigned and proton connectivities were confirmed with the 2D method. ConclusionIn vivo 1D and 2D spectroscopic examination of muscle can be successfully recorded at 7T and is now available to assess lipid alterations as well as other metabolites present with disease. T1 and T2 values were also determined in soleus muscle of male healthy volunteers.

  15. Frustrating a correlated superconductor: the 2D Attractive Hubbard Model in an external magnetic field

    NASA Astrophysics Data System (ADS)

    Zhao, Hongbo; Engelbrecht, Jan R.

    2000-03-01

    At the Mean Field level (G. Murthy and R. Shankar, J. Phys. Condens. Matter, 7) (1995), the frustration due to an external field first makes the uniform BCS ground state unstable to an incommensurate (qne0) superconducting state and then to a spin-polarized Fermi Liquid state. Our interest is how fluctuations modify this picture, as well as the normal state of this system which has a quantum critical point. We use the Fluctuation-Exchange Approximation for the 2D Attractive Hubbard Model, to study this system beyond the Mean-Field level. Earlier work in zero field has shown that this numerical method successfully captures the critical scaling of the KT superconducting transition upon cooling in the normal state. Here we investigate how the pair-breaking external field modifies this picture, and the development of incommensurate pairing.

  16. Experimental determination of the correlation properties of plasma turbulence using 2D BES systems

    NASA Astrophysics Data System (ADS)

    Fox, M. F. J.; Field, A. R.; van Wyk, F.; Ghim, Y.-c.; Schekochihin, A. A.; the MAST Team

    2017-04-01

    A procedure is presented to map from the spatial correlation parameters of a turbulent density field (the radial and binormal correlation lengths and wavenumbers, and the fluctuation amplitude) to correlation parameters that would be measured by a beam emission spectroscopy (BES) diagnostic. The inverse mapping is also derived, which results in resolution criteria for recovering correct correlation parameters, depending on the spatial response of the instrument quantified in terms of point-spread functions (PSFs). Thus, a procedure is presented that allows for a systematic comparison between theoretical predictions and experimental observations. This procedure is illustrated using the Mega-Ampere Spherical Tokamak BES system and the validity of the underlying assumptions is tested on fluctuating density fields generated by direct numerical simulations using the gyrokinetic code GS2. The measurement of the correlation time, by means of the cross-correlation time-delay method, is also investigated and is shown to be sensitive to the fluctuating radial component of velocity, as well as to small variations in the spatial properties of the PSFs.

  17. Superconducting correlations and thermodynamic properties in 2D square and triangular t-J model

    NASA Astrophysics Data System (ADS)

    Ogata, Masao

    2006-03-01

    Equal-time superconducting correlation functions of the two-dimensional t-J model on the square lattice are studied using high-temperature expansion method.[1] The sum of the pairing correlation, its spatial dependence and correlation length are obtained down to T ˜0.2t. By comparison of single-particle contributions in the correlation functions, we find effective attractive interactions between quasi-particles in dx^2-y^2-wave channel. It is shown that d-wave correlation grows rapidly at low temperatures for the doping 0.1 < δ< 0.5. The temperature for this growth is roughly scaled by J/2. This is in sharp contrast to the Hubbard model in a weak or intermediate coupling region, where there are few numerical evidences of superconductivity. We also study the possible d- and f-wave pairing in the triangular t-J model.[2] When t>0 with hole doping, a rapid growth of effective d-wave paring interaction is found that indicates the resonating-valence-bond superconductivity. In contrast, when t<0, where the ferromagnetic- and antiferromagnetic correlation compete, correlation lengths of the f-wave triplet paring tends to diverge around δ=0.6, although its effective interaction is small. This result is compared and discussed with the recently discovered superconductor, NaxCoO2.yH2O, where Co atoms form a triangular lattice. Specific heat in low temperatures are also obtained in the high-temperature expansion method. We will discuss that the doping dependence of the specific heat coefficient, γ, agrees with experimental data. [1] T. Koretsune and M. Ogata, J. Phys. Soc. Japan 74, 1390 (2005). [2] T. Koretsune and M. Ogata, Phys. Rev. Lett. 89, 116401 (2002), and Phys. Rev. B72, 134513 (2005).

  18. Anisotropic Power Law Strain Correlations in Sheared Amorphous 2D Solids

    SciTech Connect

    Maloney, C. E.; Robbins, M. O.

    2009-06-05

    The local deformation of steadily sheared two-dimensional Lennard-Jones glasses is studied via computer simulations at zero temperature. In the quasistatic limit, spatial correlations in the incremental strain field are highly anisotropic. The data show power law behavior with a strong angular dependence of the scaling exponent, and the strongest correlations along the directions of maximal shear stress. These results support the notion that the jamming transition at the onset of flow is critical, but suggest unusual critical behavior. The predicted behavior is testable through experiments on sheared amorphous materials such as bubble rafts, foams, emulsions, granular packings, and other systems where particle displacements can be tracked.

  19. Multielectron Correlation in High-Harmonic Generation: A 2D Model Analysis

    SciTech Connect

    Sukiasyan, Suren; McDonald, Chris; Destefani, Carlos; Brabec, Thomas; Ivanov, Misha Yu.

    2009-06-05

    We analyze the role of multielectron dynamics in high-harmonic generation spectroscopy, using an example of a two-electron system. We identify and systematically quantify the importance of correlation and exchange effects. One of the main sources for correlation is identified to be the polarization of the ion by the recombining continuum electron. This effect, which plays an important qualitative and quantitative role, seriously undermines the validity of the standard approaches to high-harmonic generation, which ignore the contribution of excited ionic states to the radiative recombination of the continuum electron.

  20. FT-Raman study of cinchonine aqueous solutions with varying pH; 2D correlation method

    NASA Astrophysics Data System (ADS)

    Wesetucha-Birczyńska, Aleksandra

    1999-05-01

    Cinchonine (C 19H 22N 2O) is one of the Cinchona tree alkaloids. It consists of two moieties, a quinoline ring and quinuclidine linked by a hydroxymethylene bridge. Each one of these parts contains nitrogen atoms, which are proton acceptor and cause that cinchonine can be treated as a weak base. For the first time the protonation effect was evidenced in the RR spectra of cinchonine while interacting with DNA (A. Wesetucha-Birczyńska and K. Nakamoto, J. Raman Spectrosc. 27 (1996) 915). In the current study 2D correlation method was applied to analyze the FT-Raman spectra of cin aqueous solutions with varying pH, which was regarded as external perturbation in the 1300-1700 cm -1 range, which is quinuclidine and quinoline ring stretching vibration region. These monitored fluctuations transformed into 2D spectra allows to analyze these vibrations and differentiate them.

  1. Spectrum of Mathematical Weaknesses: Related Neuropsychological Correlates.

    PubMed

    Perna, Robert; Loughan, Ashlee R; Le, Jessica; Hertza, Jeremy; Cohen, Morris J

    2015-01-01

    Math disorders have been recognized for as long as language disorders yet have received far less research. Mathematics is a complex construct and its development may be dependent on multiple cognitive abilities. Several studies have shown that short-term memory, working memory, visuospatial skills, processing speed, and various language skills relate to and may facilitate math development and performance. The hypotheses explored in this research were that children who performed worse on math achievement than on Full-Scale IQ would exhibit weaknesses in executive functions, memory, and visuoperceptual skills. Participants included 436 children (27% girls, 73% boys; age range = 5-17 years, M(age) = 9.45 years) who were referred for neuropsychological evaluations due to academic and/or behavioral problems. This article specifically focuses on the spectrum of math weakness rather than clinical disability, which has yet to be investigated in the literature. Results suggest that children with relative weakness to impairments in math were significantly more likely to have cognitive weaknesses to impairments on neuropsychological variables, as compared with children without math weaknesses. Specifically, the math-weak children exhibit a weakness to impairment on measures involving attention, language, visuoperceptual skills, memory, reading, and spelling. Overall, our results suggest that math development is multifaceted.

  2. A Comparison of 1D and 2D (Unbiased) Experimental Methods for Measuring CSAsolarDD Cross-Correlated Relaxation

    NASA Astrophysics Data System (ADS)

    Batta, Gy.; Kövér, K. E.; Kowalewski, J.

    1999-01-01

    Conventional and enhanced 1D experiments and different NOESY experiments (the 2D unbiased method) were performed for measuring CSA/DD cross-correlated relaxation on trehalose, a compound which could be approximated as a spherical top, and on simple model compounds comprisingC3vsymmetry (CHCl3, triphenylsilane (TPSi)). The comparison gives experimental evidence for the equivalence of the methods within the limits of the two-spin approach. 1D data are evaluated with both the simple initial rate and the Redfield relaxation matrix approach. The 2D data are obtained from the so-called transfer matrix using the Perrin-Gipe eigenvalue/eigenvector method. For the improved performance of the 2D method, anX-filtered (HHH) NOESY is suggested at the natural abundance of13C (or other dilute, low γ species). Also, experimental parameters crucial for reliable CSA data are tested (e.g., the impact of insufficient relaxation delay). Error estimation is carried out for fair comparison of methods. Revised liquid state1H and13C (29Si) CSA data are presented for chloroform and TPSi.

  3. Study of the equilibrium vacancy ensemble in aluminum using 1D- and 2D-angular correlation of annihilation radiation

    SciTech Connect

    Fluss, M.J.; Berko, S.; Chakraborty, B.; Hoffmann, K.R.; Lippel, P.; Siegel, R.W.

    1985-03-12

    One- and two-dimensional angular correlation of positron-electron annihilation radiation (1D and 2D-ACAR) data have been obtained between 293 and 903 K for single crystals of aluminum. The peak counting rates vs temperature, which were measured using the 1D-ACAR technique, provide a model independent value for the temperature dependence of the positron trapping probability. Using these results it is possible to strip out the Bloch state contribution from the observed 2D-ACAR surfaces and then compare the resulting defect ACAR surfaces to calculated 2D-ACAR surfaces for positrons annihilating from the Bloch, monovacancy, and divacancy-trapped states. The result of this comparison is that the presence of an increasing equilibrium divacancy population is consistent with the observed temperature dependence of ACAR data at high temperature in Al and that the present results when compared to earlier studies on Al indicate that the ratio of the trapping rates at divacancies and monovacancies is of order two.

  4. Impact of lens distortions on strain measurements obtained with 2D digital image correlation

    NASA Astrophysics Data System (ADS)

    Lava, P.; Van Paepegem, W.; Coppieters, S.; De Baere, I.; Wang, Y.; Debruyne, D.

    2013-05-01

    The determination of strain fields based on displacements obtained via digital image correlation (DIC) at the micro-strain level (≤1000 μm/m) is still a cumbersome task. In particular when high-strain gradients are involved, e.g. in composite materials with multidirectional fibre reinforcement, uncertainties in the experimental setup and errors in the derivation of the displacement fields can substantially hamper the strain identification process. In this contribution, the aim is to investigate the impact of lens distortions on strain measurements. To this purpose, we first perform pure rigid body motion experiments, revealing the importance of precise correction of lens distortions. Next, a uni-axial tensile test on a textile composite with spatially varying high strain gradients is performed, resulting in very accurately determined strains along the fibers of the material.

  5. Experimental validation of 2D uncertainty quantification for digital image correlation.

    SciTech Connect

    Reu, Phillip L.

    2010-03-01

    Because digital image correlation (DIC) has become such an important and standard tool in the toolbox of experimental mechanicists, a complete uncertainty quantification of the method is needed. It should be remembered that each DIC setup and series of images will have a unique uncertainty based on the calibration quality and the image and speckle quality of the analyzed images. Any pretest work done with a calibrated DIC stereo-rig to quantify the errors using known shapes and translations, while useful, do not necessarily reveal the uncertainty of a later test. This is particularly true with high-speed applications where actual test images are often less than ideal. Work has previously been completed on the mathematical underpinnings of DIC uncertainty quantification and is already published, this paper will present corresponding experimental work used to check the validity of the uncertainty equations.

  6. Immunohistochemical validation and expression profiling of NKG2D ligands in a wide spectrum of human epithelial neoplasms.

    PubMed

    Fujita, Hiromi; Hatanaka, Yutaka; Sutoh, Yoichi; Suzuki, Yuta; Oba, Koji; Hatanaka, Kanako C; Mitsuhashi, Tomoko; Otsuka, Noriyuki; Fugo, Kazunori; Kasahara, Masanori; Matsuno, Yoshihiro

    2015-03-01

    The MHC class I-chain-related proteins (MICs) and the UL16-binding proteins (ULBPs) are inducible stress response molecules that work as activators of a specific receptor, NKG2D, which is expressed on effector cells, such as NK cells and subsets of T cells. In this study, we sought to explore the biological significance of NKG2D ligands in human neoplasms by comprehensively examining the immunohistochemical expression profile of NKG2D ligands in a variety of human epithelial neoplasms. Following careful validation of the immunohistochemical specificity and availability of anti-human ULBP antibodies for formalin-fixed paraffin-embedded (FFPE) materials, the expression of NKG2D ligands was analyzed in FFPE tissue microarrays comprising 22 types of epithelial neoplastic tissue with their non-neoplastic counterpart from various organs. Hierarchical cluster analysis demonstrated a positive relationship among ULBP2/6, ULBP3, ULBP1, and ULBP5, whose expression patterns were similar across all of the neoplastic tissues examined. In contrast, MICA/B, as well as ULBP4, did not appear to be related to any other ligand. These expression profiles of NKG2D ligands in human neoplasms based on well-validated specific antibodies, followed by hierarchical cluster analysis, should help to clarify some functional aspects of these molecules in cancer biology, and also provide a path to the development of novel tumor-type-specific treatment strategies.

  7. Immunohistochemical Validation and Expression Profiling of NKG2D Ligands in a Wide Spectrum of Human Epithelial Neoplasms

    PubMed Central

    Fujita, Hiromi; Hatanaka, Yutaka; Sutoh, Yoichi; Suzuki, Yuta; Oba, Koji; Hatanaka, Kanako C.; Mitsuhashi, Tomoko; Otsuka, Noriyuki; Fugo, Kazunori; Kasahara, Masanori

    2015-01-01

    The MHC class I-chain-related proteins (MICs) and the UL16-binding proteins (ULBPs) are inducible stress response molecules that work as activators of a specific receptor, NKG2D, which is expressed on effector cells, such as NK cells and subsets of T cells. In this study, we sought to explore the biological significance of NKG2D ligands in human neoplasms by comprehensively examining the immunohistochemical expression profile of NKG2D ligands in a variety of human epithelial neoplasms. Following careful validation of the immunohistochemical specificity and availability of anti-human ULBP antibodies for formalin-fixed paraffin-embedded (FFPE) materials, the expression of NKG2D ligands was analyzed in FFPE tissue microarrays comprising 22 types of epithelial neoplastic tissue with their non-neoplastic counterpart from various organs. Hierarchical cluster analysis demonstrated a positive relationship among ULBP2/6, ULBP3, ULBP1, and ULBP5, whose expression patterns were similar across all of the neoplastic tissues examined. In contrast, MICA/B, as well as ULBP4, did not appear to be related to any other ligand. These expression profiles of NKG2D ligands in human neoplasms based on well-validated specific antibodies, followed by hierarchical cluster analysis, should help to clarify some functional aspects of these molecules in cancer biology, and also provide a path to the development of novel tumor-type-specific treatment strategies. PMID:25473094

  8. Importance of the Correlation between Width and Length in the Shape Analysis of Nanorods: Use of a 2D Size Plot To Probe Such a Correlation.

    PubMed

    Zhao, Zhihua; Zheng, Zhiqin; Roux, Clément; Delmas, Céline; Marty, Jean-Daniel; Kahn, Myrtil L; Mingotaud, Christophe

    2016-08-22

    Analysis of nanoparticle size through a simple 2D plot is proposed in order to extract the correlation between length and width in a collection or a mixture of anisotropic particles. Compared to the usual statistics on the length associated with a second and independent statistical analysis of the width, this simple plot easily points out the various types of nanoparticles and their (an)isotropy. For each class of nano-objects, the relationship between width and length (i.e., the strong or weak correlations between these two parameters) may suggest information concerning the nucleation/growth processes. It allows one to follow the effect on the shape and size distribution of physical or chemical processes such as simple ripening. Various electron microscopy pictures from the literature or from the authors' own syntheses are used as examples to demonstrate the efficiency and simplicity of the proposed 2D plot combined with a multivariate analysis.

  9. Two-dimensional (2D) Chemiluminescence (CL) correlation spectroscopy for studying thermal oxidation of isotactic polypropylene (iPP)

    NASA Astrophysics Data System (ADS)

    Shinzawa, Hideyuki; Hagihara, Hideaki; Suda, Hiroyuki; Mizukado, Jyunji

    2016-11-01

    Application of the two-dimensional (2D) correlation spectroscopy is extended to Chemiluminescence (CL) spectra of isotactic polypropylene (iPP) under thermally induced oxidation. Upon heating, the polymer chains of the iPP undergoes scissoring and fragmentation to develop several intermediates. While different chemical species provides the emission at different wavelength regions, entire feature of the time-dependent CL spectra of the iPP samples were complicated by the presence of overlapped contributions from singlet oxygen (1O2) and carbonyl species within sample. 2D correlation spectra showed notable enhancement of the spectral resolution to provide penetrating insight into the thermodynamics of the polymer system. For example, the, oxidation induce scissoring and fragmentation of the polymer chains to develop the carbonyl group. Further reaction results in the consumption of the carbonyl species and subsequent production of different 1O2 species each developed in different manner. Consequently, key information on the thermal oxidation can be extracted in a surprisingly simple manner without any analytical expression for the actual response curves of spectral intensity signals during the reaction.

  10. A New Blind 2D-RAKE Receiver Based on CMA Criteria for Spread Spectrum Systems Suitable for Software Defined Radio Architecture

    NASA Astrophysics Data System (ADS)

    Takayama, Kei; Kamiya, Yukihiro; Fujii, Takeo; Suzuki, Yasuo

    Spread Spectrum (SS) has been widely used for various wireless systems such as cellular systems, wireless local area network (LAN) and so on. Using multiple antennas at the receiver, two-dimensional (2D) RAKE is realized over the time- and the space-domain. However, it should be noted that the 2D-RAKE receiver must detect the bit timing prior to the RAKE combining. In case of deep fading, it is often difficult to detect it due to low signal-to-noise power ratio (SNR). To solve this problem, we propose a new blind 2D-RAKE receiver based on the constant modulus algorithm (CMA). Since it does not need a priori bit timing detection, it is possible to compensate frequency selective fading even in very low SNR environments. The proposed method is particularly suitable for the software defined radio (SDR) architecture. The performance of the proposed method is investigated through computer simulations.

  11. Rapid identification of Pterocarpus santalinus and Dalbergia louvelii by FTIR and 2D correlation IR spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhang, Fang-Da; Xu, Chang-Hua; Li, Ming-Yu; Huang, An-Min; Sun, Su-Qin

    2014-07-01

    Since Pterocarpus santalinus and Dalbergia louvelii, which are of precious Rosewood, are very similar in their appearance and anatomy characteristics, cheaper Hongmu D. louvelii is often illegally used to impersonate valuable P. santalinus, especially in Chinese furniture manufacture. In order to develop a rapid and effective method for easy confused wood furniture differentiation, we applied tri-step identification method, i.e., conventional infrared spectroscopy (FT-IR), second derivative infrared (SD-IR) spectroscopy and two-dimensional correlation infrared (2DCOS-IR) spectroscopy to investigate P. santalinus and D. louvelii furniture. According to FT-IR and SD-IR spectra, it has been found two unconditional stable difference at 848 cm-1 and 700 cm-1 and relative stable differences at 1735 cm-1, 1623 cm-1, 1614 cm-1, 1602 cm-1, 1509 cm-1, 1456 cm-1, 1200 cm-1, 1158 cm-1, 1055 cm-1, 1034 cm-1 and 895 cm-1 between D. louvelii and P. santalinus IR spectra. The stable discrepancy indicates that the category of extractives is different between the two species. Besides, the relative stable differences imply that the content of holocellulose in P. santalinus is more than that of D. louvelii, whereas the quantity of extractives in D. louvelii is higher. Furthermore, evident differences have been observed in their 2DCOS-IR spectra of 1550-1415 cm-1 and 1325-1030 cm-1. P. santalinus has two strong auto-peaks at 1459 cm-1 and 1467 cm-1, three mid-strong auto-peaks at 1518 cm-1, 1089 cm-1 and 1100 cm-1 and five weak auto-peaks at 1432 cm-1, 1437 cm-1, 1046 cm-1, 1056 cm-1 and 1307 cm-1 while D. louvelii has four strong auto-peaks at 1465 cm-1, 1523 cm-1, 1084 cm-1 and 1100 cm-1, four mid-strong auto-peaks at 1430 cm-1, 1499 cm-1, 1505 cm-1 and 1056 cm-1 and two auto-peaks at 1540 cm-1 and 1284 cm-1. This study has proved that FT-IR integrated with 2DCOS-IR could be applicable for precious wood furniture authentication in a direct, rapid and holistic manner.

  12. Speech Spectrum's Correlation with Speakers' Eysenck Personality Traits

    PubMed Central

    Hu, Chao; Wang, Qiandong; Short, Lindsey A.; Fu, Genyue

    2012-01-01

    The current study explored the correlation between speakers' Eysenck personality traits and speech spectrum parameters. Forty-six subjects completed the Eysenck Personality Questionnaire. They were instructed to verbally answer the questions shown on a computer screen and their responses were recorded by the computer. Spectrum parameters of /sh/ and /i/ were analyzed by Praat voice software. Formant frequencies of the consonant /sh/ in lying responses were significantly lower than that in truthful responses, whereas no difference existed on the vowel /i/ speech spectrum. The second formant bandwidth of the consonant /sh/ speech spectrum was significantly correlated with the personality traits of Psychoticism, Extraversion, and Neuroticism, and the correlation differed between truthful and lying responses, whereas the first formant frequency of the vowel /i/ speech spectrum was negatively correlated with Neuroticism in both response types. The results suggest that personality characteristics may be conveyed through the human voice, although the extent to which these effects are due to physiological differences in the organs associated with speech or to a general Pygmalion effect is yet unknown. PMID:22439014

  13. Speech spectrum's correlation with speakers' Eysenck personality traits.

    PubMed

    Hu, Chao; Wang, Qiandong; Short, Lindsey A; Fu, Genyue

    2012-01-01

    The current study explored the correlation between speakers' Eysenck personality traits and speech spectrum parameters. Forty-six subjects completed the Eysenck Personality Questionnaire. They were instructed to verbally answer the questions shown on a computer screen and their responses were recorded by the computer. Spectrum parameters of /sh/ and /i/ were analyzed by Praat voice software. Formant frequencies of the consonant /sh/ in lying responses were significantly lower than that in truthful responses, whereas no difference existed on the vowel /i/ speech spectrum. The second formant bandwidth of the consonant /sh/ speech spectrum was significantly correlated with the personality traits of Psychoticism, Extraversion, and Neuroticism, and the correlation differed between truthful and lying responses, whereas the first formant frequency of the vowel /i/ speech spectrum was negatively correlated with Neuroticism in both response types. The results suggest that personality characteristics may be conveyed through the human voice, although the extent to which these effects are due to physiological differences in the organs associated with speech or to a general Pygmalion effect is yet unknown.

  14. SU-E-T-422: Correlation Between 2D Passing Rates and 3D Dose Differences for Pretreatment VMAT QA

    SciTech Connect

    Jin, X; Xie, C

    2014-06-01

    Purpose: Volumetric modulated arc therapy (VMAT) quality assurance (QA) is typically using QA methods and action levels taken from fixedbeam intensity-modulated radiotherapy (IMRT) QA methods. However, recent studies demonstrated that there is no correlation between the percent gamma passing rate (%GP) and the magnitude of dose discrepancy between the planned dose and the actual delivered dose for IMRT. The purpose of this study is to investigate whether %GP is correlated with clinical dosimetric difference for VMAT. Methods: Twenty nasopharyngeal cancer (NPC) patients treated with dual-arc simultaneous integrated boost VMAT and 20 esophageal cancer patients treated with one-arc VMAT were enrolled in this study. Pretreatment VMAT QA was performed by a 3D diode array ArcCheck. Acceptance criteria of 2%/2mm, 3%/3mm, and 4%/4mm were applied for 2D %GP. Dose values below 10% of the per-measured normalization maximum dose were ignored.Mean DVH values obtained from 3DVH software and TPS were calculated and percentage dose differences were calculated. Statistical correlation between %GP and percent dose difference was studied by using Pearson correlation. Results: The %GP for criteria 2%/2mm, 3%/3mm, and 4%/4mm were 82.33±4.45, 93.47±2.31, 97.13±2.41, respectively. Dose differences calculated from 3DVH and TPS for beam isocenter, mean dose of PTV, maximum dose of PTV, D2 of PTV and D98 of PTV were -1.04±3.24, -0.74±1.71, 2.92±3.62, 0.89±3.29, -1.46±1.97, respectively. No correction were found between %GP and dose differences. Conclusion: There are weak correlations between the 2D %GP and dose differences calculated from 3DVH. The %GP acceptance criteria of 3%/3mm usually applied for pretreatment QA of IMRT and VMAT is not indicating strong clinical correlation with 3D dose difference. 3D dose reconstructions on patient anatomy may be necessary for physicist to predict the accuracy of delivered dose for VMAT QA.

  15. Four divalent transition metal carboxyarylphosphonate compounds: Hydrothermal synthesis, structural chemistry and generalized 2D FTIR correlation spectroscopy studies

    SciTech Connect

    Lei Ran; Chai Xiaochuan; Mei Hongxin; Zhang Hanhui; Chen Yiping; Sun Yanqiong

    2010-07-15

    Four divalent transition metal carboxyarylphosphonates, [Ni(4,4'-bipy)H{sub 2}L{sup 1}(HL{sup 1}){sub 2}(H{sub 2}O){sub 2}].2H{sub 2}O 1, [Ni{sub 2}(4,4'-bipy)(L{sup 2})(OH)(H{sub 2}O){sub 2}].3H{sub 2}O 2, Mn(phen){sub 2}(H{sub 2}L{sup 1}){sub 2}3 and Mn(phen)(HL{sup 2}) 4 (H{sub 3}L{sup 1}=p-H{sub 2}O{sub 3}PCH{sub 2}-C{sub 6}H{sub 4}-COOH, H{sub 3}L{sup 2}=m-H{sub 2}O{sub 3}PCH{sub 2}-C{sub 6}H{sub 4}-COOH, 4,4'-bipy=4,4'-bipyridine, phen=1,10-phenanthroline) were synthesized under hydrothermal conditions. 1 features 1D linear chains built from Ni(II) ions bridging 4,4'-bipy. In 2, neighboring Ni{sub 4} cluster units are connected by pairs of H{sub 3}L{sup 2} ligands to form 1D double-crankshaft chains, which are interconnected by pairs of 4,4'-bipy into 2D sheets. 3 exhibits 2D supramolecular layers via the R{sub 2}{sup 2}(8) ringed hydrogen bonding units. 4 has 1D ladderlike chains, in which the 4-membered rings are cross-linked by the organic moieties of the H{sub 3}L{sup 2} ligands. Additionally, 2D FTIR correlation analysis is applied with thermal and magnetic perturbation to clarify the structural changes of functional groups from H{sub 3}L{sup 1} and H{sub 3}L{sup 2} ligands in the compounds more efficiently. - Graphical abstract: A series of divalent transition metal carboxyarylphosphonate compounds were synthesized under hydrothermal conditions. The figure displays 2D sheet structure with large windows in compound 2.

  16. Near-infrared (NIR) monitoring of Nylon 6 during quenching studied by projection two-dimensional (2D) correlation spectroscopy

    NASA Astrophysics Data System (ADS)

    Shinzawa, Hideyuki; Mizukado, Junji

    2016-11-01

    Evolutionary change in supermolecular structure of Nylon 6 during its melt-quenched process was studied by Near-infrared (NIR) spectroscopy. Time-resolved NIR spectra was measured by taking the advantage of high-speed NIR monitoring based on an acousto-optic tunable filter (AOTF). Fine spectral features associated with the variation of crystalline and amorphous structure occurring in relatively short time scale were readily captured. For example, synchronous and asynchronous 2D correlation spectra reveal the initial decrease in the contribution of the NIR band at 1485 nm due to the amorphous structure, predominantly existing in the melt Nylon 6. This is then followed by the emerging contribution of the band intensity at 1535 nm associated with the crystalline structure. Consequently, the results clearly demonstrate a definite advantage of the high-speed NIR monitoring for analyzing fleeting phenomena.

  17. Robust initialization of 2D-3D image registration using the projection-slice theorem and phase correlation

    SciTech Connect

    Bom, M. J. van der; Bartels, L. W.; Gounis, M. J.; Homan, R.; Timmer, J.; Viergever, M. A.; Pluim, J. P. W.

    2010-04-15

    Purpose: The image registration literature comprises many methods for 2D-3D registration for which accuracy has been established in a variety of applications. However, clinical application is limited by a small capture range. Initial offsets outside the capture range of a registration method will not converge to a successful registration. Previously reported capture ranges, defined as the 95% success range, are in the order of 4-11 mm mean target registration error. In this article, a relatively computationally inexpensive and robust estimation method is proposed with the objective to enlarge the capture range. Methods: The method uses the projection-slice theorem in combination with phase correlation in order to estimate the transform parameters, which provides an initialization of the subsequent registration procedure. Results: The feasibility of the method was evaluated by experiments using digitally reconstructed radiographs generated from in vivo 3D-RX data. With these experiments it was shown that the projection-slice theorem provides successful estimates of the rotational transform parameters for perspective projections and in case of translational offsets. The method was further tested on ex vivo ovine x-ray data. In 95% of the cases, the method yielded successful estimates for initial mean target registration errors up to 19.5 mm. Finally, the method was evaluated as an initialization method for an intensity-based 2D-3D registration method. The uninitialized and initialized registration experiments had success rates of 28.8% and 68.6%, respectively. Conclusions: The authors have shown that the initialization method based on the projection-slice theorem and phase correlation yields adequate initializations for existing registration methods, thereby substantially enlarging the capture range of these methods.

  18. Sleep Disturbances and Correlates of Children with Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Liu, Xianchen; Hubbard, Julie A.; Fabes, Richard A.; Adam, James B.

    2006-01-01

    This study examined sleep patterns, sleep problems, and their correlates in children with autism spectrum disorders (ASD). Subjects consisted of 167 ASD children, including 108 with autistic disorder, 27 with Asperger's syndrome, and 32 with other diagnoses of ASD. Mean age was 8.8 years (SD = 4.2), 86% were boys. Parents completed a…

  19. Neural Correlates of Restricted, Repetitive Behaviors in Autism Spectrum Disorders

    DTIC Science & Technology

    2012-10-01

    Repetitive Behaviors in Autism Spectrum Disorders PRINCIPAL INVESTIGATOR: Dara Manoach CONTRACTING ORGANIZATION: Massachusetts...Annual 3. DATES COVERED 06September2011–05September2012 4. TITLE AND SUBTITLE Neural Correlates of Restricted , Repetitive Behaviors in Autism ...complete, we will test the hypothesis that restrictive , repetitive behaviors (RRBs) are associated with specific reductions in brain

  20. Monitoring guanidinium-induced structural changes in ribonuclease proteins using Raman spectroscopy and 2D correlation analysis.

    PubMed

    Brewster, Victoria L; Ashton, Lorna; Goodacre, Royston

    2013-04-02

    Assessing the stability of proteins by comparing their unfolding profiles is a very important characterization and quality control step for any biopharmaceutical, and this is usually measured by fluorescence spectroscopy. In this paper we propose Raman spectroscopy as a rapid, noninvasive alternative analytical method and we shall show this has enhanced sensitivity and can therefore reveal very subtle protein conformational changes that are not observed with fluorescence measurements. Raman spectroscopy is a powerful nondestructive method that has a strong history of applications in protein characterization. In this work we describe how Raman microscopy can be used as a fast and reliable method of tracking protein unfolding in the presence of a chemical denaturant. We have compared Raman spectroscopic data to the equivalent samples analyzed using fluorescence spectroscopy in order to validate the Raman approach. Calculations from both Raman and fluorescence unfolding curves of [D]50 values and Gibbs free energy correlate well with each other and more importantly agree with the values found in the literature for these proteins. In addition, 2D correlation analysis has been performed on both Raman and fluorescence data sets in order to allow further comparisons of the unfolding behavior indicated by each method. As many biopharmaceuticals are glycosylated in order to be functional, we compare the unfolding profiles of a protein (RNase A) and a glycoprotein (RNase B) as measured by Raman spectroscopy and discuss the implications that glycosylation has on the stability of the protein.

  1. Rapid discrimination of extracts of Chinese propolis and poplar buds by FT-IR and 2D IR correlation spectroscopy

    NASA Astrophysics Data System (ADS)

    Wu, Yan-Wen; Sun, Su-Qin; Zhao, Jing; Li, Yi; Zhou, Qun

    2008-07-01

    The extract of Chinese propolis (ECP) has recently been adulterated with that of poplar buds (EPB), because most of ECP is derived from the poplar plant, and ECP and EPB have almost identical chemical compositions. It is very difficult to differentiate them by using the chromatographic methods such as high performance liquid chromatography (HPLC) and gas chromatography (GC). Therefore, how to effectively discriminate these two mixtures is a problem to be solved urgently. In this paper, a rapid method for discriminating ECP and EPB was established by the Fourier transform infrared (FT-IR) spectra combined with the two-dimensional infrared correlation (2D IR) analysis. Forty-three ECP and five EPB samples collected from different areas of China were analyzed by the FT-IR spectroscopy. All the ECP and EPB samples tested show similar IR spectral profiles. The significant differences between ECP and EPB appear in the region of 3000-2800 cm -1 of the spectra. Based on such differences, the two species were successfully classified with the soft independent modeling of class analogy (SIMCA) pattern recognition technique. Furthermore, these differences were well validated by a series of temperature-dependent dynamic FT-IR spectra and the corresponding 2D IR plots. The results indicate that the differences in these two natural products are caused by the amounts of long-chain alkyl compounds (including long-chain alkanes, long-chain alkyl esters and long chain alkyl alcohols) in them, rather than the flavonoid compounds, generally recognized as the bioactive substances of propolis. There are much more long-chain alkyl compounds in ECP than those in EPB, and the carbon atoms of the compounds in ECP remain in an order Z-shaped array, but those in EPB are disorder. It suggests that FT-IR and 2D IR spectroscopy can provide a valuable method for the rapid differentiation of similar natural products, ECP and EPB. The IR spectra could directly reflect the integrated chemical

  2. SU-E-T-20: A Correlation Study of 2D and 3D Gamma Passing Rates for Prostate IMRT Plans

    SciTech Connect

    Zhang, D; Wang, B; Ma, C; Deng, X

    2015-06-15

    Purpose: To investigate the correlation between the two-dimensional gamma passing rate (2D %GP) and three-dimensional gamma passing rate (3D %GP) in prostate IMRT quality assurance. Methods: Eleven prostate IMRT plans were randomly selected from the clinical database and were used to obtain dose distributions in the phantom and patient. Three types of delivery errors (MLC bank sag errors, central MLC errors and monitor unit errors) were intentionally introduced to modify the clinical plans through an in-house Matlab program. This resulted in 187 modified plans. The 2D %GP and 3D %GP were analyzed using different dose-difference and distance-toagreement (1%-1mm, 2%-2mm and 3%-3mm) and 20% dose threshold. The 2D %GP and 3D %GP were then compared not only for the whole region, but also for the PTVs and critical structures using the statistical Pearson’s correlation coefficient (γ). Results: For different delivery errors, the average comparison of 2D %GP and 3D %GP showed different conclusions. The statistical correlation coefficients between 2D %GP and 3D %GP for the whole dose distribution showed that except for 3%/3mm criterion, 2D %GP and 3D %GP of 1%/1mm criterion and 2%/2mm criterion had strong correlations (Pearson’s γ value >0.8). Compared with the whole region, the correlations of 2D %GP and 3D %GP for PTV were better (the γ value for 1%/1mm, 2%/2mm and 3%/3mm criterion was 0.959, 0.931 and 0.855, respectively). However for the rectum, there was no correlation between 2D %GP and 3D %GP. Conclusion: For prostate IMRT, the correlation between 2D %GP and 3D %GP for the PTV is better than that for normal structures. The lower dose-difference and DTA criterion shows less difference between 2D %GP and 3D %GP. Other factors such as the dosimeter characteristics and TPS algorithm bias may also influence the correlation between 2D %GP and 3D %GP.

  3. Selection of the NIR region for a regression model of the ethanol concentration in fermentation process by an online NIR and mid-IR dual-region spectrometer and 2D heterospectral correlation spectroscopy.

    PubMed

    Nishii, Takashi; Genkawa, Takuma; Watari, Masahiro; Ozaki, Yukihiro

    2012-01-01

    A new selection procedure of an informative near-infrared (NIR) region for regression model building is proposed that uses an online NIR/mid-infrared (mid-IR) dual-region spectrometer in conjunction with two-dimensional (2D) NIR/mid-IR heterospectral correlation spectroscopy. In this procedure, both NIR and mid-IR spectra of a liquid sample are acquired sequentially during a reaction process using the NIR/mid-IR dual-region spectrometer; the 2D NIR/mid-IR heterospectral correlation spectrum is subsequently calculated from the obtained spectral data set. From the calculated 2D spectrum, a NIR region is selected that includes bands of high positive correlation intensity with mid-IR bands assigned to the analyte, and used for the construction of a regression model. To evaluate the performance of this procedure, a partial least-squares (PLS) regression model of the ethanol concentration in a fermentation process was constructed. During fermentation, NIR/mid-IR spectra in the 10000 - 1200 cm(-1) region were acquired every 3 min, and a 2D NIR/mid-IR heterospectral correlation spectrum was calculated to investigate the correlation intensity between the NIR and mid-IR bands. NIR regions that include bands at 4343, 4416, 5778, 5904, and 5955 cm(-1), which result from the combinations and overtones of the C-H group of ethanol, were selected for use in the PLS regression models, by taking the correlation intensity of a mid-IR band at 2985 cm(-1) arising from the CH(3) asymmetric stretching vibration mode of ethanol as a reference. The predicted results indicate that the ethanol concentrations calculated from the PLS regression models fit well to those obtained by high-performance liquid chromatography. Thus, it can be concluded that the selection procedure using the NIR/mid-IR dual-region spectrometer combined with 2D NIR/mid-IR heterospectral correlation spectroscopy is a powerful method for the construction of a reliable regression model.

  4. High Resolution Infrared Spectrum of the ν7+ν8 Band of the Trans-C2H2D2 Molecule

    NASA Astrophysics Data System (ADS)

    Ziatkova, A. G.; Aslapovskaya, Yu. S.; Gromova, O. V.; Bekhtereva, E. S.; Fomchenko, A. L.

    2017-02-01

    High resolution spectrum of the trans-C2H2D2 molecule is analyzed on the basis of the Ground State Combination Difference method in the region 1450-1650 cm-1, in which the hybrid ν7 + ν8 band is located. The analysis is performed in the framework of the model which takes into account the Coriolis interaction with the ν8 + ν10 band. The b-type transitions that in their turn, allow more experimental data on the ν7 + ν8 band to be obtained, are determined for this band for the first time.

  5. 2D continuous spectrum of shear Alfvén waves in the presence of a magnetic island

    NASA Astrophysics Data System (ADS)

    Biancalani, Alessandro; Chen, Liu; Pegoraro, Francesco; Zonca, Fulvio

    2011-02-01

    The radial structure of the continuous spectrum of shear Alfvén modes is calculated in the presence of a magnetic island in tokamak plasmas. Modes with the same helicity as the magnetic island are considered in a slab model approximation. In this framework, with an appropriate rotation of the coordinates the problem reduces to two dimensions. Geometrical effects due to the shape of the flux surface's cross-section are retained to all orders. On the other hand, we neglect toroidal couplings but fully take into account curvature effects responsible for the beta-induced gap in the low-frequency part of the continuous spectrum. New continuum accumulation points are found at the O-point of the magnetic island. The beta-induced Alfvén eigenmodes (BAE) continuum accumulation point is found to be positioned at the separatrix flux surface. The most remarkable result is the modification of the BAE continuum accumulation point frequency, due to the presence of the magnetic island.

  6. Anisotropic multi-resolution analysis in 2D, application to long-range correlations in cloud mm-radar fields

    SciTech Connect

    Davis, A.B.; Clothiaux, E.

    1999-03-01

    Because of Earth`s gravitational field, its atmosphere is strongly anisotropic with respect to the vertical; the effect of the Earth`s rotation on synoptic wind patterns also causes a more subtle form of anisotropy in the horizontal plane. The authors survey various approaches to statistically robust anisotropy from a wavelet perspective and present a new one adapted to strongly non-isotropic fields that are sampled on a rectangular grid with a large aspect ratio. This novel technique uses an anisotropic version of Multi-Resolution Analysis (MRA) in image analysis; the authors form a tensor product of the standard dyadic Haar basis, where the dividing ratio is {lambda}{sub z} = 2, and a nonstandard triadic counterpart, where the dividing ratio is {lambda}{sub x} = 3. The natural support of the field is therefore 2{sup n} pixels (vertically) by 3{sup n} pixels (horizontally) where n is the number of levels in the MRA. The natural triadic basis includes the French top-hat wavelet which resonates with bumps in the field whereas the Haar wavelet responds to ramps or steps. The complete 2D basis has one scaling function and five wavelets. The resulting anisotropic MRA is designed for application to the liquid water content (LWC) field in boundary-layer clouds, as the prevailing wind advects them by a vertically pointing mm-radar system. Spatial correlations are notoriously long-range in cloud structure and the authors use the wavelet coefficients from the new MRA to characterize these correlations in a multifractal analysis scheme. In the present study, the MRA is used (in synthesis mode) to generate fields that mimic cloud structure quite realistically although only a few parameters are used to control the randomness of the LWC`s wavelet coefficients.

  7. Study on antibacterial alginate-stabilized copper nanoparticles by FT-IR and 2D-IR correlation spectroscopy

    PubMed Central

    Díaz-Visurraga, Judith; Daza, Carla; Pozo, Claudio; Becerra, Abraham; von Plessing, Carlos; García, Apolinaria

    2012-01-01

    Background The objective of this study was to clarify the intermolecular interaction between antibacterial copper nanoparticles (Cu NPs) and sodium alginate (NaAlg) by Fourier transform infrared spectroscopy (FT-IR) and to process the spectra applying two-dimensional infrared (2D-IR) correlation analysis. To our knowledge, the addition of NaAlg as a stabilizer of copper nanoparticles has not been previously reported. It is expected that the obtained results will provide valuable additional information on: (1) the influence of reducing agent ratio on the formation of copper nanoparticles in order to design functional nanomaterials with increased antibacterial activity, and (2) structural changes related to the incorporation of Cu NPs into the polymer matrix. Methods Cu NPs were prepared by microwave heating using ascorbic acid as reducing agent and NaAlg as stabilizing agent. The characterization of synthesized Cu NPs by ultraviolet visible spectroscopy, transmission electron microscopy (TEM), electron diffraction analysis, X-ray diffraction (XRD), and semiquantitative analysis of the weight percentage composition indicated that the average particle sizes of Cu NPs are about 3–10 nm, they are spherical in shape, and consist of zerovalent Cu and Cu2O. Also, crystallite size and relative particle size of stabilized Cu NPs were calculated by XRD using Scherrer’s formula and FT from the X-ray diffraction data. Thermogravimetric analysis, differential thermal analysis, differential scanning calorimetry (DSC), FT-IR, second-derivative spectra, and 2D-IR correlation analysis were applied to studying the stabilization mechanism of Cu NPs by NaAlg molecules. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of stabilized Cu NPs against five bacterial strains (Staphylococccus aureus ATCC 6538P, Escherichia coli ATCC 25922 and O157: H7, and Salmonella enterica serovar Typhimurium ATCC 13311 and 14028) were evaluated with macrodilution

  8. Does pharmacogenetic testing for CYP450 2D6 and 2C19 among patients with diagnoses within the schizophrenic spectrum reduce treatment costs?

    PubMed

    Herbild, Louise; Andersen, Stig E; Werge, Thomas; Rasmussen, Henrik B; Jürgens, Gesche

    2013-10-01

    The effect of pharmacogenetic testing for CYP450 2D6 and 2C19 on treatment costs have not yet been documented. This study used Danish patient registers to calculate healthcare costs of treating patients with diagnoses within the schizophrenic spectrum for 1 year with or without pharmacogenetic testing for polymorphisms in the genes for the CYP2D6 and CYP2C19 enzymes. In a randomized, controlled trial, stratified with respect to metabolizer genotype, 104 patients were assigned to treatment based on pharmacogenetic testing and 103 patients to treatment as usual. Random exclusion of extensive and intermediate metabolizers was used to increase the frequency of extreme metabolizers (poor metabolizers and ultrarapid metabolizers for CYP2D6) to 20% in both groups. Cost differences were analysed at several levels including (i) overall healthcare expenditure, (ii) psychiatric hospital cost (iii) nonpsychiatric hospital cost, (iv) primary care spending and (v) pharmaceuticals. Statistically significant differences in costs of psychiatric care dependent on metabolizer status were found between intervention groups. Pharmacogenetic testing significantly reduced costs among the extreme metabolizers (poor metabolizers and ultrarapid metabolizers) to 28%. Use of primary care services and pharmaceuticals was also affected by the intervention.This study confirms earlier findings that extreme metabolizers (poor and ultrarapid metabolizers) incur higher costs than similar patients with a normal metabolizer genotype. However, this study shows that these excess costs can be reduced by pharmacogenetic testing. Pharmacogenetic testing for CYP2D6 and CYP2C19 could thus be considered as a means of curtailing high psychiatric treatment costs among extreme metabolizers.

  9. Severity of Cortical Thinning Correlates With Schizophrenia Spectrum Symptoms

    PubMed Central

    Greenstein, Deanna; Shora, Lorie; Dillard-Broadnax, Diane; Gochman, Peter; Clasen, Liv S.; Berman, Rebecca A.; Rapoport, Judith L.; Gogtay, Nitin; Ordóñez, Anna E.

    2016-01-01

    Objective This study investigated the relationship between regional cortical gray matter thinning and symptoms of schizophrenia spectrum personality disorders (PDs) in siblings of patients with childhood-onset schizophrenia (COS). Method 66 siblings of patients with COS were assessed for symptoms of schizophrenia spectrum PDs (avoidant, paranoid, schizoid, schizotypal). Structural magnetic resonance images were obtained at approximately 2-year intervals from the siblings and from 62 healthy volunteers, matched for age, sex, ethnicity, and handedness. Cortical thickness measures were extracted. Mixed effect regression models were used to test the relationship between symptoms and cortical gray matter thickness. Cortical thinning was also tested longitudinally in healthy volunteers and siblings. Results Cortical thinning was found to correlate with symptoms of schizotypal and, to a lesser extent, schizoid PDs. Thinning was most pronounced in the left temporal and parietal lobes and right frontal and parietal regions. Gray matter loss was found to be continuous with that measured in COS. Longitudinal thinning trajectories were found not to differ between siblings and healthy volunteers. Conclusion The present investigation of cortical thinning in siblings of patients with COS indicates that symptoms of schizophrenia spectrum PDs correlate with regional gray matter loss. This finding supports the idea of cortical thinning as a schizophrenia endophenotype. PMID:26802780

  10. Radiographic Trabecular 2D and 3D Parameters of Proximal Femoral Bone Cores Correlate with Each Other and with Yield Stress

    PubMed Central

    Steines, Daniel; Liew, Siau-Way; Arnaud, Claude; Voracek, Rene Vargas; Nazarian, Ara; Müller, Ralph; Snyder, Brian; Hess, Patrick; Lang, Philipp

    2010-01-01

    Introduction We compared morphometric measurements of trabecular patterns in two-dimensional (2D) projection radiographic images of cores from cadaver proximal femoral bones with conceptually equivalent measurements from three-dimensional (3D) μCT images. Methods Seven cadaver proximal femora provided 47 excised cores from seven regions. Digitized radiographs of those cores were processed with software that extracts trabecular patterns. Measurements of their distribution, geometry, and connectivity were compared with 3D parameters of similar definition derived from μCT of those cores. The relationship between 2D and 3D measurements and yield stress was also examined. Results 2D measurements strongly correlated with conceptually equivalent measurements obtained using 3D μCT. In all cases, the correlation coefficients were high, ranging from r=0.84 (p<0.001) to r=0.93 (p<0.001). The correlation coefficients between 2D and 3D measurements and yield stress of the cores were also high (r=0.60 and 0.82, p<0.001 respectively). Conclusions These findings provide correlative and biomechanical evidence supporting the qualitative similarity of 2D microstructural parameters extracted from plain proximal femoral core X-ray images to conceptually equivalent 3D microstuctural measurements of those same cores. PMID:19319618

  11. Dynamics-based selective 2D {sup 1}H/{sup 1}H chemical shift correlation spectroscopy under ultrafast MAS conditions

    SciTech Connect

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy

    2015-05-28

    Dynamics plays important roles in determining the physical, chemical, and functional properties of a variety of chemical and biological materials. However, a material (such as a polymer) generally has mobile and rigid regions in order to have high strength and toughness at the same time. Therefore, it is difficult to measure the role of mobile phase without being affected by the rigid components. Herein, we propose a highly sensitive solid-state NMR approach that utilizes a dipolar-coupling based filter (composed of 12 equally spaced 90° RF pulses) to selectively measure the correlation of {sup 1}H chemical shifts from the mobile regions of a material. It is interesting to find that the rotor-synchronized dipolar filter strength decreases with increasing inter-pulse delay between the 90° pulses, whereas the dipolar filter strength increases with increasing inter-pulse delay under static conditions. In this study, we also demonstrate the unique advantages of proton-detection under ultrafast magic-angle-spinning conditions to enhance the spectral resolution and sensitivity for studies on small molecules as well as multi-phase polymers. Our results further demonstrate the use of finite-pulse radio-frequency driven recoupling pulse sequence to efficiently recouple weak proton-proton dipolar couplings in the dynamic regions of a molecule and to facilitate the fast acquisition of {sup 1}H/{sup 1}H correlation spectrum compared to the traditional 2D NOESY (Nuclear Overhauser effect spectroscopy) experiment. We believe that the proposed approach is beneficial to study mobile components in multi-phase systems, such as block copolymers, polymer blends, nanocomposites, heterogeneous amyloid mixture of oligomers and fibers, and other materials.

  12. Length of psychiatric hospitalization is correlated with CYP2D6 functional status in inpatients with major depressive disorder

    PubMed Central

    Ruaño, Gualberto; Szarek, Bonnie L; Villagra, David; Gorowski, Krystyna; Kocherla, Mohan; Seip, Richard L; Goethe, John W; Schwartz, Harold I

    2016-01-01

    Aim This study aimed to determine the effect of the CYP2D6 genotype on the length of hospitalization stay for patients treated for major depressive disorder. Methods A total of 149 inpatients with a diagnosis of major depressive disorder at the Institute of Living, Hartford Hospital (CT, USA), were genotyped to detect altered alleles in the CYP2D6 gene. Prospectively defined drug metabolism indices (metabolic reserve, metabolic alteration and allele alteration) were determined quantitatively and assessed for their relationship to length of hospitalization stay. Results Hospital stay was significantly longer in deficient CYP2D6 metabolizers (metabolic reserve <2) compared with functional or suprafunctional metabolizers (metabolic reserve ≥2; 7.8 vs 5.7 days, respectively; p = 0.002). Conclusion CYP2D6 enzymatic functional status significantly affected length of hospital stay, perhaps due to reduced efficacy or increased side effects of the medications metabolized by the CYP2D6 isoenzyme. Functional scoring of CYP2D6 alleles may have a substantial impact on the quality of care, patient satisfaction and the economics of psychiatric treatment. PMID:23734807

  13. The correlation between CYP2D6 isoenzyme activity and haloperidol efficacy and safety profile in patients with alcohol addiction during the exacerbation of the addiction

    PubMed Central

    Sychev, Dmitry Alekseevich; Zastrozhin, Mikhail Sergeevich; Smirnov, Valery Valerieevich; Grishina, Elena Anatolievna; Savchenko, Ludmila Mikhailovna; Bryun, Evgeny Alekseevich

    2016-01-01

    Background Today, it is proved that isoenzymes CYP2D6 and CYP3A4 are involved in metabolism of haloperidol. In our previous investigation, we found a medium correlation between the efficacy and safety of haloperidol and the activity of CYP3A4 in patients with alcohol abuse. Objective The aim of this study was to evaluate the correlation between the activity of CYP2D6 and the efficacy and safety of haloperidol in patients with diagnosed alcohol abuse. Methods The study involved 70 men (average age: 40.83±9.92 years) with alcohol addiction. A series of psychometric scales were used in the research. The activity of CYP2D6 was evaluated by high-performance liquid chromatography with mass spectrometry using the ratio of 6-hydroxy-1,2,3,4-tetrahydro-beta-carboline to pinoline. Genotyping of CYP2D6 (1846G>A) was performed using real-time polymerase chain reaction. Results According to results of correlation analysis, statistically significant values of Spearman correlation coefficient (rs) between the activity of CYP2D6 and the difference of points in psychometric scale were obtained in patients receiving haloperidol in injection form (Sheehan Clinical Anxiety Rating Scale =−0.721 [P<0.001] and Udvald for Kliniske Undersogelser Side Effect Rating Scale =0.692 [P<0.001]) and in those receiving haloperidol in tablet form (Covi Anxiety Scale =−0.851 [P<0.001] and Udvald for Kliniske Undersogelser Side Effect Rating Scale =0.797 [P<0.001]). Conclusion This study demonstrated the correlations between the activity of CYP2D6 isozyme and the efficacy and safety of haloperidol in patients with alcohol addiction. PMID:27695358

  14. Detection of diluted contaminants on chicken carcasses using a two-dimensional scatter plot based on a two-dimensional hyperspectral correlation spectrum.

    PubMed

    Wu, Wei; Chen, Gui-Yun; Wu, Ming-Qing; Yu, Zhen-Wei; Chen, Kun-Jie

    2017-03-20

    A two-dimensional (2D) scatter plot method based on the 2D hyperspectral correlation spectrum is proposed to detect diluted blood, bile, and feces from the cecum and duodenum on chicken carcasses. First, from the collected hyperspectral data, a set of uncontaminated regions of interest (ROIs) and four sets of contaminated ROIs were selected, whose average spectra were treated as the original spectrum and influenced spectra, respectively. Then, the difference spectra were obtained and used to conduct correlation analysis, from which the 2D hyperspectral correlation spectrum was constructed using the analogy method of 2D IR correlation spectroscopy. Two maximum auto-peaks and a pair of cross peaks appeared at 656 and 474 nm. Therefore, 656 and 474 nm were selected as the characteristic bands because they were most sensitive to the spectral change induced by the contaminants. The 2D scatter plots of the contaminants, clean skin, and background in the 474- and 656-nm space were used to distinguish the contaminants from the clean skin and background. The threshold values of the 474- and 656-nm bands were determined by receiver operating characteristic (ROC) analysis. According to the ROC results, a pixel whose relative reflectance at 656 nm was greater than 0.5 and relative reflectance at 474 nm was lower than 0.3 was judged as a contaminated pixel. A region with more than 50 pixels identified was marked in the detection graph. This detection method achieved a recognition rate of up to 95.03% at the region level and 31.84% at the pixel level. The false-positive rate was only 0.82% at the pixel level. The results of this study confirm that the 2D scatter plot method based on the 2D hyperspectral correlation spectrum is an effective method for detecting diluted contaminants on chicken carcasses.

  15. Plasmonic spectrum on 1D and 2D periodic arrays of rod-shape metal nanoparticle pairs with different core patterns for biosensor and solar cell applications

    NASA Astrophysics Data System (ADS)

    Kumara, N. T. R. N.; Chou Chau, Yuan-Fong; Huang, Jin-Wei; Huang, Hung Ji; Lin, Chun-Ting; Chiang, Hai-Pang

    2016-11-01

    Simulations of surface plasmon resonance (SPR) on the near field intensity and absorption spectra of one-dimensional (1D) and two-dimensional (2D) periodic arrays of rod-shape metal nanoparticle (MNP) pairs using the finite element method (FEM) and taking into account the different core patterns for biosensor and solar cell applications are investigated. A tunable optical spectrum corresponding to the transverse SPR modes is observed. The peak resonance wavelength (λ res) can be shifted to red as the core patterns in rod-shape MNPs have been changed. We find that the 2D periodic array of core-shell MNP pairs (case 2) exhibit a red shifted SPR that can be tuned the gap enhancement and absorption efficiency simultaneously over an extended wavelength range. The tunable optical performances give us a qualitative idea of the geometrical properties of the periodic array of rod-shape MNP pairs on SPRs that can be as a promising candidate for plasmonic biosensor and solar cell applications.

  16. Discrimination of adulterated milk based on two-dimensional correlation spectroscopy (2D-COS) combined with kernel orthogonal projection to latent structure (K-OPLS).

    PubMed

    Yang, Renjie; Liu, Rong; Xu, Kexin; Yang, Yanrong

    2013-12-01

    A new method for discrimination analysis of adulterated milk and pure milk is proposed by combining two-dimensional correlation spectroscopy (2D-COS) with kernel orthogonal projection to latent structure (K-OPLS). Three adulteration types of milk with urea, melamine, and glucose were prepared, respectively. The synchronous 2D spectra of adulterated milk and pure milk samples were calculated. Based on the characteristics of 2D correlation spectra of adulterated milk and pure milk, a discriminant model of urea-tainted milk, melamine-tainted milk, glucose-tainted milk, and pure milk was built by K-OPLS. The classification accuracy rates of unknown samples were 85.7, 92.3, 100, and 87.5%, respectively. The results show that this method has great potential in the rapid discrimination analysis of adulterated milk and pure milk.

  17. The radio-optical correlation in steep-spectrum quasars

    NASA Astrophysics Data System (ADS)

    Serjeant, Stephen; Rawlings, Steve; Lacy, Mark; Maddox, Stephen J.; Baker, Joanne C.; Clements, Dave; Lilje, Per B.

    1998-03-01

    Using complete samples of steep-spectrum quasars, we present evidence for a correlation between radio and optical luminosity which is not caused by selection effects, nor caused by an orientation dependence (such as relativistic beaming), nor a by-product of cosmic evolution. We argue that this rules out models of jet formation in which there are no parameters in common with the production of the optical continuum. This is arguably the most direct evidence to date for a close link between accretion onto a black hole and the fuelling of relativistic jets. The correlation also provides a natural explanation for the presence of aligned optical/radio structures in only the most radio-luminous high-redshift galaxies.

  18. One Dimensional(1D)-to-2D Crossover of Spin Correlations in the 3D Magnet ZnMn2O4

    PubMed Central

    Disseler, S. M.; Chen, Y.; Yeo, S.; Gasparovic, G.; Piccoli, P. M. B.; Schultz, A. J.; Qiu, Y.; Huang, Q.; Cheong, S.-W.; Ratcliff, W.

    2015-01-01

    We report on the intriguing evolution of the dynamical spin correlations of the frustrated spinel ZnMn2O4. Inelastic neutron scattering and magnetization studies reveal that the dynamical correlations at high temperatures are 1D. At lower temperature, these dynamical correlations become 2D. Surprisingly, the dynamical correlations condense into a quasi 2D Ising-like ordered state, making this a rare observation of two dimensional order on the spinel lattice. Remarkably, 3D ordering is not observed down to temperatures as low as 300 mK. This unprecedented dimensional crossover stems from frustrated exchange couplings due to the huge Jahn-Teller distortions around Mn3+ ions on the spinel lattice. PMID:26644220

  19. One Dimensional(1D)-to-2D Crossover of Spin Correlations in the 3D Magnet ZnMn2O4

    DOE PAGES

    Disseler, S. M.; Chen, Y.; Yeo, S.; ...

    2015-12-08

    In this paper we report on the intriguing evolution of the dynamical spin correlations of the frustrated spinel ZnMn2O4. Inelastic neutron scattering and magnetization studies reveal that the dynamical correlations at high temperatures are 1D. At lower temperature, these dynamical correlations become 2D. Surprisingly, the dynamical correlations condense into a quasi 2D Ising-like ordered state, making this a rare observation of two dimensional order on the spinel lattice. Remarkably, 3D ordering is not observed down to temperatures as low as 300 mK. This unprecedented dimensional crossover stems from frustrated exchange couplings due to the huge Jahn-Teller distortions around Mn3+ ionsmore » on the spinel lattice.« less

  20. One Dimensional(1D)-to-2D Crossover of Spin Correlations in the 3D Magnet ZnMn2O4

    SciTech Connect

    Disseler, S. M.; Chen, Y.; Yeo, S.; Gasparovic, G.; Piccoli, P. M. B.; Schultz, A. J.; Qiu, Y.; Huang, Q.; Cheong, S. -W.; Ratcliff, W.

    2015-12-08

    In this paper we report on the intriguing evolution of the dynamical spin correlations of the frustrated spinel ZnMn2O4. Inelastic neutron scattering and magnetization studies reveal that the dynamical correlations at high temperatures are 1D. At lower temperature, these dynamical correlations become 2D. Surprisingly, the dynamical correlations condense into a quasi 2D Ising-like ordered state, making this a rare observation of two dimensional order on the spinel lattice. Remarkably, 3D ordering is not observed down to temperatures as low as 300 mK. This unprecedented dimensional crossover stems from frustrated exchange couplings due to the huge Jahn-Teller distortions around Mn3+ ions on the spinel lattice.

  1. Reduced Expression of Histone Methyltransferases KMT2C and KMT2D Correlates with Improved Outcome in Pancreatic Ductal Adenocarcinoma.

    PubMed

    Dawkins, Joshua B N; Wang, Jun; Maniati, Eleni; Heward, James A; Koniali, Lola; Kocher, Hemant M; Martin, Sarah A; Chelala, Claude; Balkwill, Frances R; Fitzgibbon, Jude; Grose, Richard P

    2016-08-15

    Genes encoding the histone H3 lysine 4 methyltransferases KMT2C and KMT2D are subject to deletion and mutation in pancreatic ductal adenocarcinoma (PDAC), where these lesions identify a group of patients with a more favorable prognosis. In this study, we demonstrate that low KMT2C and KMT2D expression in biopsies also defines better outcome groups, with median survivals of 15.9 versus 9.2 months (P = 0.029) and 19.9 versus 11.8 months (P = 0.001), respectively. Experiments with eight human pancreatic cell lines showed attenuated cell proliferation when these methyltransferases were depleted, suggesting that this improved outcome may reflect a cell-cycle block with diminished progression from G0-G1 RNA-seq analysis of PDAC cell lines following KMT2C or KMT2D knockdown identified 31 and 124 differentially expressed genes, respectively, with 19 genes in common. Gene-set enrichment analysis revealed significant downregulation of genes related to cell-cycle and growth. These data were corroborated independently by examining KMT2C/D signatures extracted from the International Cancer Genome Consortium and The Cancer Genome Atlas datasets. Furthermore, these experiments highlighted a potential role for NCAPD3, a condensin II complex subunit, as an outcome predictor in PDAC using existing gene expression series. Kmt2d depletion in KC/KPC cell lines also led to an increased response to the nucleoside analogue 5-fluorouracil, suggesting that lower levels of this methyltransferase may mediate the sensitivity of PDAC to particular treatments. Therefore, it may also be therapeutically beneficial to target these methyltransferases in PDAC, especially in those patients demonstrating higher KTM2C/D expression. Cancer Res; 76(16); 4861-71. ©2016 AACR.

  2. Reduced Expression of Histone Methyltransferases KMT2C and KMT2D Correlates with Improved Outcome in Pancreatic Ductal Adenocarcinoma

    PubMed Central

    Dawkins, Joshua B.N.; Wang, Jun; Maniati, Eleni; Heward, James A.; Koniali, Lola; Kocher, Hemant M.; Martin, Sarah A.; Chelala, Claude; Balkwill, Frances R.; Fitzgibbon, Jude; Grose, Richard P.

    2017-01-01

    Genes encoding the histone H3 lysine 4 methyltransferases KMT2C and KMT2D are subject to deletion and mutation in pancreatic ductal adenocarcinoma (PDAC), where these lesions identify a group of patients with a more favorable prognosis. In this study, we demonstrate that low KMT2C and KMT2D expression in biopsies also defines better outcome groups, with median survivals of 15.9 versus 9.2 months (P = 0.029) and 19.9 versus 11.8 months (P = 0.001), respectively. Experiments with eight human pancreatic cell lines showed attenuated cell proliferation when these methyltransferases were depleted, suggesting that this improved outcome may reflect a cell-cycle block with diminished progression from G0–G1. RNA-seq analysis of PDAC cell lines following KMT2C or KMT2D knockdown identified 31 and 124 differentially expressed genes, respectively, with 19 genes in common. Gene-set enrichment analysis revealed significant downregulation of genes related to cell-cycle and growth. These data were corroborated independently by examining KMT2C/D signatures extracted from the International Cancer Genome Consortium and The Cancer Genome Atlas datasets. Furthermore, these experiments highlighted a potential role for NCAPD3, a condensin II complex subunit, as an outcome predictor in PDAC using existing gene expression series. Kmt2d depletion in KC/KPC cell lines also led to an increased response to the nucleoside analogue 5-fluorouracil, suggesting that lower levels of this methyltransferase may mediate the sensitivity of PDAC to particular treatments. Therefore, it may also be therapeutically beneficial to target these methyltransferases in PDAC, especially in those patients demonstrating higher KTM2C/D expression. PMID:27280393

  3. Striatal D2/D3 Receptor Availability is Inversely Correlated with Cannabis Consumption in Chronic Marijuana Users

    PubMed Central

    Albrecht, Daniel S.; Skosnik, Patrick D.; Vollmer, Jennifer M.; Brumbaugh, Margaret S.; Perry, Kevin M.; Mock, Bruce H.; Zheng, Qi-Huang; Federici, Lauren A.; Patton, Elizabeth A.; Herring, Christine M.; Yoder, Karmen K.

    2012-01-01

    BACKGROUND Although the incidence of cannabis abuse/dependence in Americans is rising, the neurobiology of cannabis addiction is not well understood. Imaging studies have demonstrated deficits in striatal D2/D3 receptor availability in several substance-dependent populations. However, this has not been studied in currently-using chronic cannabis users. OBJECTIVE The purpose of this study was to compare striatal D2/D3 receptor availability between currently-using chronic cannabis users and healthy controls. METHODS Eighteen right-handed males age 18–34 were studied. Ten subjects were chronic cannabis users; eight were demographically matched controls. Subjects underwent a [11C] raclopride (RAC) PET scan. Striatal RAC binding potential (BPND) was calculated on a voxel-wise basis. Prior to scanning, urine samples were obtained from cannabis users for quantification of urine Δ-9-tetrahydrocannabinol (THC) and THC metabolites (11-nor-Δ-9-THC-9-carboxylic acid; THC-COOH and 11-hydroxy-THC;OH-THC). Results There were no differences in D2/D3 receptor availability between cannabis users and controls. Voxel-wise analyses revealed that RAC BPND values were negatively associated with both urine levels of cannabis metabolites and self-report of recent cannabis consumption. CONCLUSIONS In this sample, current cannabis use was not associated with deficits in striatal D2/D3 receptor availability. There was an inverse relationship between chronic cannabis use and striatal RAC BPND. Additional studies are needed to identify the neurochemical consequences of chronic cannabis use on the dopamine system. PMID:22909787

  4. Two-dimensional (2D) infrared correlation study of the structural characterization of a surface immobilized polypeptide film stimulated by pH

    NASA Astrophysics Data System (ADS)

    Chae, Boknam; Son, Seok Ho; Kwak, Young Jun; Jung, Young Mee; Lee, Seung Woo

    2016-11-01

    The pH-induced structural changes to surface immobilized poly (L-glutamic acid) (PLGA) films were examined by Fourier transform infrared (FTIR) spectroscopy and two-dimensional (2D) correlation analysis. Significant spectral changes were observed in the FTIR spectra of the surface immobilized PLGA film between pH 6 and 7. The 2D correlation spectra constructed from the pH-dependent FTIR spectra of the surface immobilized PLGA films revealed the spectral changes induced by the alternations of the protonation state of the carboxylic acid group in the PLGA side chain. When the pH was increased from 6 to 8, weak spectral changes in the secondary structure of the PLGA main chain were induced by deprotonation of the carboxylic acid side group.

  5. An unambiguous identification of 2D electron gas features in the photoluminescence spectrum of AlGaN/GaN heterostructures

    NASA Astrophysics Data System (ADS)

    Jana, Dipankar; Sharma, T. K.

    2016-07-01

    A fast and non-destructive method for probing the true signatures of 2D electron gas (2DEG) states in AlGaN/GaN heterostructures is presented. Two broad features superimposed with interference oscillations are observed in the low temperature photoluminescence (PL) spectrum. The two features are identified as the ground and excited 2DEG states which are confirmed by comparing the PL spectra of as-grown and top barrier layer etched samples. Broad PL features disappear at a certain temperature along with the associated interference oscillations. Furthermore, the two broad PL features depicts specific temperature and excitation intensity dependencies which make them easily distinguishable from the bandedge excitonic or defect related PL features. The presence of strong interference oscillations associated with the 2DEG PL features is explained by considering the localized generation of PL signal at the AlGaN/GaN heterointerface. Finally, a large value of the polarization induced electric field of ~1.01 MV cm-1 is reported from PL measurements for AlGaN/GaN HEMT structures. It became possible only when the true identification of 2DEG features was made possible by the proposed method.

  6. Fourier Transform Microwave Spectrum of Propene-3-d1 (CH2=CHCH2D), Quadrupole Coupling Constants of Deuterium and a Semiexperimental Equilibrium Structure of Propene.

    PubMed

    Demaison, Jean; Craig, Norman C; Gurusinghe, Ranil Malaka; Tubergen, Michael John; Rudolph, Heinz Dieter; Coudert, Laurent H; Szalay, Peter G; Császár, Attila G

    2017-04-03

    The ground state rotational spectrum of propene-3-d1, CH2=CHCH2D, was measured by Fourier transform microwave spectroscopy. Transitions were assigned for the two conformers, one with the D atom in the symmetry plane (S) and the other with the D atom out of plane (A). The energy difference between the two conformers was calculated to be 6.5 cm-1, the S conformer having lower energy. The quadrupole hyperfine structure due to deuterium was resolved and analyzed for the two conformers. The experimental quadrupole coupling and the centrifugal distortion constants compared favorably to their ab initio counterparts. Ground state rotational constants for the S conformer are 40582.157(9), 9067.024(1), and 7766.0165(12) MHz. Ground state rotational constants for the A conformer are 43403.75(3), 8658.961(2), and 7718.247(2) MHz. For the A conformer, a small tunneling splitting (19 MHz) due to internal rotation was observed and analyzed. Using the new rotational constants of this work as well as those previously determined for the 13C species and for some deuterium-substituted species from the literature, a new semiexperimental equilibrium structure was determined and its high accuracy was confirmed. The difficulty in obtaining accurate coordinates for the out-of-plane hydrogen atom is discussed.

  7. Wavelength selection based on two-dimensional correlation spectroscopy: application to noninvasive hemoglobin measurement by dynamic spectrum

    NASA Astrophysics Data System (ADS)

    Zhang, Shengzhao; Zhang, Linna; Li, Zhe; Li, Gang; Lin, Ling

    2016-10-01

    Dynamic spectrum (DS) method is one of the noninvasive approaches to measure the concentration of components in human blood based on the application of photoplethysmogram (PPG). One of the targets of the DS method is to predict the hemoglobin concentration in human blood noninvasively. In previous works, the usually used wavelength in the spectrum is 600-1100 nm which is regarded as the analysis "window" in human tissues. Optimum wavelengths for measurements of hemoglobin concentration have not been investigated yet. In order to improve the precision and reliability of hemoglobin measurements, a method for wavelength selection based on two-dimension (2D) correlation spectroscopy has been studied in this paper. By analyzing the 2D correlation spectroscopy which is generated by the DS data from subject with different blood hemoglobin concentrations, the wavelength bands which are sensible to hemoglobin concentrations in DS can be found. We developed calibration models between the DS data and hemoglobin concentration based on data from 57 subjects. The correlation coefficient is 0.68 in the test set of the model using the whole wavelength band (600-1100nm), while in the test set of the model using the selected wavelength band (850- 950nm) the correlation coefficient is 0.87. Results show the feasibility of wavelength selection utilizing 2Dcorrelation spectroscopy.

  8. Neural Correlates of Restricted, Repetitive Behaviors in Autism Spectrum Disorders

    DTIC Science & Technology

    2013-10-01

    Restricted , Repetitive Behaviors in Autism Spectrum Disorders 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-11-1-0774 5c... Repetitive Behaviors in Autism Spectrum Disorders PRINCIPAL INVESTIGATOR: Associate Professor of Psychiatry Manoach, Dara CONTRACTING...speech network of individuals with autism spectrum disorder NeuroImage: Clinical. in press. CONCLUSION

  9. Neural Correlates of Restricted, Repetitive Behaviors in Autism Spectrum Disorders

    DTIC Science & Technology

    2013-10-01

    Repetitive Behaviors in Autism Spectrum Disorders PRINCIPAL INVESTIGATOR: Manoach, Dara CONTRACTING ORGANIZATION: Massachusetts General... Behaviors in Autism Spectrum Disorders 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-11-1-0773 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Dara...with autism spectrum disorder NeuroImage: Clinical. in press. CONCLUSION We have completed data

  10. Study of Positronium in Low-k Dielectric Films by means of 2D-Angular Correlation Experiments at a High-Intensity Slow-Positron Beam

    SciTech Connect

    Gessmann, T; Petkov, M P; Weber, M H; Lynn, K G; Rodbell, K P; Asoka-Kumar, P; Stoeffl, W; Howell, R H

    2001-06-20

    Depth-resolved measurements of the two-dimensional angular correlation of annihilation radiation (2D-ACAR) were performed at the high-intensity slow-positron beam of Lawrence Livermore National Laboratory. We studied the formation of positronium in thin films of methyl-silsesquioxane (MSSQ) spin-on glass containing open-volume defects in the size of voids. Samples with different average void sizes were investigated and positronium formation could be found in all cases. The width of the angular correlation related to the annihilation of parapositronium increased with the void size indicating the annihilation of non-thermalized parapositronium.

  11. A study on correlation between 2D and 3D gamma evaluation metrics in patient-specific quality assurance for VMAT

    SciTech Connect

    Rajasekaran, Dhanabalan Jeevanandam, Prakash; Sukumar, Prabakar; Ranganathan, Arulpandiyan; Johnjothi, Samdevakumar; Nagarajan, Vivekanandan

    2014-01-01

    In this study, we investigated the correlation between 2-dimensional (2D) and 3D gamma analysis using the new PTW OCTAVIUS 4D system for various parameters. For this study, we selected 150 clinically approved volumetric-modulated arc therapy (VMAT) plans of head and neck (50), thoracic (esophagus) (50), and pelvic (cervix) (50) sites. Individual verification plans were created and delivered to the OCTAVIUS 4D phantom. Measured and calculated dose distributions were compared using the 2D and 3D gamma analysis by global (maximum), local and selected (isocenter) dose methods. The average gamma passing rate for 2D global gamma analysis in coronal and sagittal plane was 94.81% ± 2.12% and 95.19% ± 1.76%, respectively, for commonly used 3-mm/3% criteria with 10% low-dose threshold. Correspondingly, for the same criteria, the average gamma passing rate for 3D planar global gamma analysis was 95.90% ± 1.57% and 95.61% ± 1.65%. The volumetric 3D gamma passing rate for 3-mm/3% (10% low-dose threshold) global gamma was 96.49% ± 1.49%. Applying stringent gamma criteria resulted in higher differences between 2D planar and 3D planar gamma analysis across all the global, local, and selected dose gamma evaluation methods. The average gamma passing rate for volumetric 3D gamma analysis was 1.49%, 1.36%, and 2.16% higher when compared with 2D planar analyses (coronal and sagittal combined average) for 3 mm/3% global, local, and selected dose gamma analysis, respectively. On the basis of the wide range of analysis and correlation study, we conclude that there is no assured correlation or notable pattern that could provide relation between planar 2D and volumetric 3D gamma analysis. Owing to higher passing rates, higher action limits can be set while performing 3D quality assurance. Site-wise action limits may be considered for patient-specific QA in VMAT.

  12. Volatility-dependent 2D IR correlation analysis of traditional Chinese medicine ‘Red Flower Oil’ preparation from different manufacturers

    NASA Astrophysics Data System (ADS)

    Wu, Yan-Wen; Sun, Su-Qin; Zhou, Qun; Tao, Jia-Xun; Noda, Isao

    2008-06-01

    As a traditional Chinese medicine (TCM), 'Red Flower Oil' preparation is widely used as a household remedy in China and Southeast Asia. Usually, the preparation is a mixture of several plant essential oils with different volatile features, such as wintergreen oil, turpentine oil and clove oil. The proportions of these plant essential oils in 'Red Flower Oil' vary from different manufacturers. Thus, it is important to develop a simple and rapid evaluation method for quality assurance of the preparations. Fourier transform infrared (FT-IR) was applied and two-dimensional correlation infrared spectroscopy (2D IR) based on the volatile characteristic of samples was used to enhance the resolution of FT-IR spectra. 2D IR technique could, not only easily provide the composition and their volatile sequences in 'Red flower Oil' preparations, but also rapidly discriminate the subtle differences in products from different manufacturers. Therefore, FT-IR combined with volatility-dependent 2D IR correlation analysis provides a very fast and effective method for the quality control of essential oil mixtures in TCM.

  13. High-accuracy 2D digital image correlation measurements using low-cost imaging lenses: implementation of a generalized compensation method

    NASA Astrophysics Data System (ADS)

    Pan, Bing; Yu, Liping; Wu, Dafang

    2014-02-01

    The ideal pinhole imaging model commonly assumed for an ordinary two-dimensional digital image correlation (2D-DIC) system is neither perfect nor stable because of the existence of small out-of-plane motion of the test sample surface that occurred after loading, small out-of-plane motion of the sensor target due to temperature variation of a camera and unavoidable geometric distortion of an imaging lens. In certain cases, these disadvantages can lead to significant errors in the measured displacements and strains. Although a high-quality bilateral telecentric lens has been strongly recommended to be used in the 2D-DIC system as an essential optical component to achieve high-accuracy measurement, it is not generally applicable due to its fixed field of view, limited depth of focus and high cost. To minimize the errors associated with the imperfectness and instability of a common 2D-DIC system using a low-cost imaging lens, a generalized compensation method using a non-deformable reference sample is proposed in this work. With the proposed method, the displacement of the reference sample rigidly attached behind the test sample is first measured using 2D-DIC, and then it is fitted using a parametric model. The fitted parametric model is then used to correct the displacements of the deformed sample to remove the influences of these unfavorable factors. The validity of the proposed compensation method is first verified using out-of-plane translation, out-of-plane rotation, in-plane translation tests and their combinations. Uniaxial tensile tests of an aluminum specimen were also performed to quantitatively examine the strain accuracy of the proposed compensation method. Experiments show that the proposed compensation method is an easy-to-implement yet effective technique for achieving high-accuracy deformation measurement using an ordinary 2D-DIC system.

  14. Quantum coherence selective 2D Raman–2D electronic spectroscopy

    PubMed Central

    Spencer, Austin P.; Hutson, William O.; Harel, Elad

    2017-01-01

    Electronic and vibrational correlations report on the dynamics and structure of molecular species, yet revealing these correlations experimentally has proved extremely challenging. Here, we demonstrate a method that probes correlations between states within the vibrational and electronic manifold with quantum coherence selectivity. Specifically, we measure a fully coherent four-dimensional spectrum which simultaneously encodes vibrational–vibrational, electronic–vibrational and electronic–electronic interactions. By combining near-impulsive resonant and non-resonant excitation, the desired fifth-order signal of a complex organic molecule in solution is measured free of unwanted lower-order contamination. A critical feature of this method is electronic and vibrational frequency resolution, enabling isolation and assignment of individual quantum coherence pathways. The vibronic structure of the system is then revealed within an otherwise broad and featureless 2D electronic spectrum. This method is suited for studying elusive quantum effects in which electronic transitions strongly couple to phonons and vibrations, such as energy transfer in photosynthetic pigment–protein complexes. PMID:28281541

  15. Quantum coherence selective 2D Raman-2D electronic spectroscopy

    NASA Astrophysics Data System (ADS)

    Spencer, Austin P.; Hutson, William O.; Harel, Elad

    2017-03-01

    Electronic and vibrational correlations report on the dynamics and structure of molecular species, yet revealing these correlations experimentally has proved extremely challenging. Here, we demonstrate a method that probes correlations between states within the vibrational and electronic manifold with quantum coherence selectivity. Specifically, we measure a fully coherent four-dimensional spectrum which simultaneously encodes vibrational-vibrational, electronic-vibrational and electronic-electronic interactions. By combining near-impulsive resonant and non-resonant excitation, the desired fifth-order signal of a complex organic molecule in solution is measured free of unwanted lower-order contamination. A critical feature of this method is electronic and vibrational frequency resolution, enabling isolation and assignment of individual quantum coherence pathways. The vibronic structure of the system is then revealed within an otherwise broad and featureless 2D electronic spectrum. This method is suited for studying elusive quantum effects in which electronic transitions strongly couple to phonons and vibrations, such as energy transfer in photosynthetic pigment-protein complexes.

  16. Quantum coherence selective 2D Raman-2D electronic spectroscopy.

    PubMed

    Spencer, Austin P; Hutson, William O; Harel, Elad

    2017-03-10

    Electronic and vibrational correlations report on the dynamics and structure of molecular species, yet revealing these correlations experimentally has proved extremely challenging. Here, we demonstrate a method that probes correlations between states within the vibrational and electronic manifold with quantum coherence selectivity. Specifically, we measure a fully coherent four-dimensional spectrum which simultaneously encodes vibrational-vibrational, electronic-vibrational and electronic-electronic interactions. By combining near-impulsive resonant and non-resonant excitation, the desired fifth-order signal of a complex organic molecule in solution is measured free of unwanted lower-order contamination. A critical feature of this method is electronic and vibrational frequency resolution, enabling isolation and assignment of individual quantum coherence pathways. The vibronic structure of the system is then revealed within an otherwise broad and featureless 2D electronic spectrum. This method is suited for studying elusive quantum effects in which electronic transitions strongly couple to phonons and vibrations, such as energy transfer in photosynthetic pigment-protein complexes.

  17. Detailed landfill leachate plume mapping using 2D and 3D electrical resistivity tomography - with correlation to ionic strength measured in screens

    NASA Astrophysics Data System (ADS)

    Maurya, P. K.; Rønde, V. K.; Fiandaca, G.; Balbarini, N.; Auken, E.; Bjerg, P. L.; Christiansen, A. V.

    2017-03-01

    Leaching of organic and inorganic contamination from landfills is a serious environmental problem as surface water and aquifers are affected. In order to assess these risks and investigate the migration of leachate from the landfill, 2D and large scale 3D electrical resistivity tomography were used at a heavily contaminated landfill in Grindsted, Denmark. The inverted 2D profiles describe both the variations along the groundwater flow as well as the plume extension across the flow directions. The 3D inversion model shows the variability in the low resistivity anomaly pattern corresponding to differences in the ionic strength of the landfill leachate. Chemical data from boreholes agree well with the observations indicating a leachate plume which gradually sinks and increases in size while migrating from the landfill in the groundwater flow direction. Overall results show that the resistivity method has been very successful in delineating the landfill leachate plume and that good correlation exists between the resistivity model and leachate ionic strength.

  18. Chemical profiling and adulteration screening of Aquilariae Lignum Resinatum by Fourier transform infrared (FT-IR) spectroscopy and two-dimensional correlation infrared (2D-IR) spectroscopy.

    PubMed

    Qu, Lei; Chen, Jian-Bo; Zhang, Gui-Jun; Sun, Su-Qin; Zheng, Jing

    2017-03-05

    As a kind of expensive perfume and valuable herb, Aquilariae Lignum Resinatum (ALR) is often adulterated for economic motivations. In this research, Fourier transform infrared (FT-IR) spectroscopy is employed to establish a simple and quick method for the adulteration screening of ALR. First, the principal chemical constituents of ALR are characterized by FT-IR spectroscopy at room temperature and two-dimensional correlation infrared (2D-IR) spectroscopy with thermal perturbation. Besides the common cellulose and lignin compounds, a certain amount of resin is the characteristic constituent of ALR. Synchronous and asynchronous 2D-IR spectra indicate that the resin (an unstable secondary metabolite) is more sensitive than cellulose and lignin (stable structural constituents) to the thermal perturbation. Using a certified ALR sample as the reference, the infrared spectral correlation threshold is determined by 30 authentic samples and 6 adulterated samples. The spectral correlation coefficient of an authentic ALR sample to the standard reference should be not less than 0.9886 (p=0.01). Three commercial adulterated ALR samples are identified by the correlation threshold. Further interpretation of the infrared spectra of the adulterated samples indicates the common adulterating methods - counterfeiting with other kind of wood, adding ingredient such as sand to increase the weight, and adding the cheap resin such as rosin to increase the content of resin compounds. Results of this research prove that FT-IR spectroscopy can be used as a simple and accurate quality control method of ALR.

  19. Chemical profiling and adulteration screening of Aquilariae Lignum Resinatum by Fourier transform infrared (FT-IR) spectroscopy and two-dimensional correlation infrared (2D-IR) spectroscopy

    NASA Astrophysics Data System (ADS)

    Qu, Lei; Chen, Jian-bo; Zhang, Gui-Jun; Sun, Su-qin; Zheng, Jing

    2017-03-01

    As a kind of expensive perfume and valuable herb, Aquilariae Lignum Resinatum (ALR) is often adulterated for economic motivations. In this research, Fourier transform infrared (FT-IR) spectroscopy is employed to establish a simple and quick method for the adulteration screening of ALR. First, the principal chemical constituents of ALR are characterized by FT-IR spectroscopy at room temperature and two-dimensional correlation infrared (2D-IR) spectroscopy with thermal perturbation. Besides the common cellulose and lignin compounds, a certain amount of resin is the characteristic constituent of ALR. Synchronous and asynchronous 2D-IR spectra indicate that the resin (an unstable secondary metabolite) is more sensitive than cellulose and lignin (stable structural constituents) to the thermal perturbation. Using a certified ALR sample as the reference, the infrared spectral correlation threshold is determined by 30 authentic samples and 6 adulterated samples. The spectral correlation coefficient of an authentic ALR sample to the standard reference should be not less than 0.9886 (p = 0.01). Three commercial adulterated ALR samples are identified by the correlation threshold. Further interpretation of the infrared spectra of the adulterated samples indicates the common adulterating methods - counterfeiting with other kind of wood, adding ingredient such as sand to increase the weight, and adding the cheap resin such as rosin to increase the content of resin compounds. Results of this research prove that FT-IR spectroscopy can be used as a simple and accurate quality control method of ALR.

  20. Two-dimensional correlation spectroscopy (2D-COS) variable selection for near-infrared microscopy discrimination of meat and bone meal in compound feed.

    PubMed

    Lü, Chengxu; Chen, Longjian; Yang, Zengling; Liu, Xian; Han, Lujia

    2014-01-01

    This article presents a novel method for combining auto-peak and cross-peak information for sensitive variable selection in synchronous two-dimensional correlation spectroscopy (2D-COS). This variable selection method is then applied to the case of near-infrared (NIR) microscopy discrimination of meat and bone meal (MBM). This is of important practical value because MBM is currently banned in ruminate animal compound feed. For the 2D-COS analysis, a set of NIR spectroscopy data of compound feed samples (adulterated with varying concentrations of MBM) was pretreated using standard normal variate and detrending (SNVD) and then mapped to the 2D-COS synchronous matrix. For the auto-peak analysis, 12 main sensitive variables were identified at 6852, 6388, 6320, 5788, 5600, 5244, 4900, 4768, 4572, 4336, 4256, and 4192 cm(-1). All these variables were assigned their specific spectral structure and chemical component. For the cross-peak analysis, these variables were divided into two groups, each group containing the six sensitive variables. This grouping resulted in a correlation between the spectral variables that was in accordance with the chemical-component content of the MBM and compound feed. These sensitive variables were then used to build a NIR microscopy discrimination model, which yielded a 97% correct classification. Moreover, this method detected the presence of MBM when its concentration was less than 1% in an adulterated compound feed sample. The concentration-dependent 2D-COS-based variable selection method developed in this study has the unique advantages of (1) introducing an interpretive aspect into variable selection, (2) substantially reducing the complexity of the computations, (3) enabling the transferability of the results to discriminant analysis, and (4) enabling the efficient compression of spectral data.

  1. 2dFLenS and KiDS: determining source redshift distributions with cross-correlations

    NASA Astrophysics Data System (ADS)

    Johnson, Andrew; Blake, Chris; Amon, Alexandra; Erben, Thomas; Glazebrook, Karl; Harnois-Deraps, Joachim; Heymans, Catherine; Hildebrandt, Hendrik; Joudaki, Shahab; Klaes, Dominik; Kuijken, Konrad; Lidman, Chris; Marin, Felipe A.; McFarland, John; Morrison, Christopher B.; Parkinson, David; Poole, Gregory B.; Radovich, Mario; Wolf, Christian

    2017-03-01

    We develop a statistical estimator to infer the redshift probability distribution of a photometric sample of galaxies from its angular cross-correlation in redshift bins with an overlapping spectroscopic sample. This estimator is a minimum-variance weighted quadratic function of the data: a quadratic estimator. This extends and modifies the methodology presented by McQuinn & White. The derived source redshift distribution is degenerate with the source galaxy bias, which must be constrained via additional assumptions. We apply this estimator to constrain source galaxy redshift distributions in the Kilo-Degree imaging survey through cross-correlation with the spectroscopic 2-degree Field Lensing Survey, presenting results first as a binned step-wise distribution in the range z < 0.8, and then building a continuous distribution using a Gaussian process model. We demonstrate the robustness of our methodology using mock catalogues constructed from N-body simulations, and comparisons with other techniques for inferring the redshift distribution.

  2. Neural Correlates of Restricted, Repetitive Behaviors in Autism Spectrum Disorders

    DTIC Science & Technology

    2012-10-01

    Restricted , Repetitive Behaviors in Autism Spectrum Disorders 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-11-1-0773... Repetitive Behaviors in Autism Spectrum Disorders PRINCIPAL INVESTIGATOR: Santangelo, Susan L CONTRACTING ORGANIZATION: Massachusetts...our dataset is complete, we will test the hypothesis that restrictive , repetitive behaviors (RRBs) are associated with

  3. Neural Correlates of Restricted, Repetitive Behaviors in Autism Spectrum Disorders

    DTIC Science & Technology

    2014-12-01

    in Autism Spectrum Disorders PRINCIPAL INVESTIGATOR: Manoach, Dara CONTRACTING ORGANIZATION: Massachusetts General Hospital...Final 3. DATES COVERED 6 Sep 2011 - 5 Sep 2014 4. TITLE AND SUBTITLE Neural Corrrelates of Restricted, Repetitive Behaviors in Autism Spectrum...the NIH - Autism Center for Excellence Project to actively continue our work in autism . 15. SUBJECT TERMS nothing listed 16. SECURITY

  4. Two Keggin-type heteropolytungstates with transition metal as a central atom: Crystal structure and magnetic study with 2D-IR correlation spectroscopy

    SciTech Connect

    Chai, Feng; Chen, YiPing; You, ZhuChai; Xia, ZeMin; Ge, SuZhi; Sun, YanQiong; Huang, BiHua

    2013-06-01

    Two Keggin-type heteropolytungstates, [Co(phen)₃]₃[CoW₁₂O₄₀]·9H₂O 1 (phen=1,10-phenanthroline) and [Fe(phen)₃]₂[FeW₁₂O₄₀]·H₃O·H₂O 2, have been synthesized via the hydrothermal technique and characterized by single crystal X-ray diffraction analyses, IR, XPS, TG analysis, UV–DRS, XRD, thermal-dependent and magnetic-dependent 2D-COS IR (two-dimensional infrared correlation spectroscopy). Crystal structure analysis reveals that the polyanions in compound 1 are linked into 3D supramolecule through hydrogen bonding interactions between lattice water molecules and terminal oxygen atoms of polyanion units, and [Co(phen)₃]²⁺ cations distributed in the polyanion framework with many hydrogen bonding interactions. The XPS spectra indicate that all the Co atoms in 1 are +2 oxidation state, the Fe atoms in 2 existing with +2 and +3 mixed oxidation states. - Graphical abstract: The magnetic-dependent synchronous 2D correlation IR spectra of 1 (a), 2 (b) over 0–50 mT in the range of 600–1000 cm⁻¹, the obvious response indicate two Keggin polyanions skeleton susceptible to applied magnetic field. Highlights: • Two Keggin-type heteropolytungstates with transition metal as a central atom has been obtained. • Compound 1 forms into 3D supramolecular architecture through hydrogen bonding between water molecules and polyanions. • Magnetic-dependent 2D-IR correlation spectroscopy was introduced to discuss the magnetism of polyoxometalate.

  5. Spin Correlations and Excitations in the Quasi-2D Triangular Bilayer Spin Glass LuCoGaO4

    NASA Astrophysics Data System (ADS)

    Fritsch, K.; Granroth, G. E.; Savici, A. T.; Noad, H. M. L.; Dabkowska, H. A.; Gaulin, B. D.

    2012-02-01

    LuCoGaO4 is a layered magnetic-bilayer material wherein Co2+ magnetic moments and nonmagnetic Ga3+ ions are randomly distributed on planar triangular bilayers. This makes it an ideal case to study the interplay between geometric frustration, site disorder and low dimensionality and its influence on the magnetic ground of the system. This novel material has been grown for the first time in single crystal form at McMaster University. We have performed magnetization measurements, revealing a previously identified spin glass transition near Tf˜19K, and a Curie Weiss temperature of Tcw˜-96K, consistent with antiferromagnetic interactions[1]. We discuss time-of-flight neutron scattering measurements using SEQUOIA at SNS which elucidate the evolution of the static and dynamic spin correlations in LuCoGaO4 over a range of temperatures from T<< Tf to T>Tcw. We observe quasielastic scattering at (1/3,1/3,L) positions in reciprocal space and rods of scattering along the c*-direction, consistent with short range antiferromagnetic correlations within decoupled bilayers, and which comfirm the 2-dimensional character of this system. Inelastic scattering measurements show a gapped ˜ 12 meV spin excitation which softens and broadens in energy, filling in the gap on a temperature scale of ˜ Tcw/2. [1] Cava et al., J. Solid State Chem. 140, 337 (1998).

  6. Density fluctuation spectrum of two-dimensional correlated fermion systems

    NASA Astrophysics Data System (ADS)

    Kotani, Akihiro; Hirashima, Dai

    2012-12-01

    Density fluctuation spectrum of two-dimensional fermions that interact with short-range repulsive interaction is calculated with the self-consistent perturbation theory. The spectrum extends beyond the particle-hole continuum band in the noninteracting case because of the multiparticle excitations. At a large wave vector, a peak develops in the spectrum near the lower threshold of the particle-hole continuum. These results are compared with the recent inelastic neutron scattering experiment on two-dimensional 3He adsorbed on graphite.

  7. Nitrite reactivity of the binuclear copper site in T2D Rhus laccase: preparation of half met-NO2- T2D laccase and its correlation to half met-NO2- hemocyanin and tyrosinase.

    PubMed

    Spira, D J; Solomon, E I

    1983-04-29

    Through chemistry directly comparable to that of the hemocyanins and tyrosinase, half met-NO2- T2D laccase derivatives have been prepared; this NO2- reactivity entails both two electron oxidation of the cuprous binuclear site in deoxy T2D laccase and one electron reduction of the coupled cupric site in the met derivative. However, the labile ligand substitution chemistry and lack of dimer formation in half met-NO2- T2D are in marked contrast to behavior of the simpler binuclear copper containing proteins under analagous conditions. This chemistry supports and extends our earlier studies on the ferrocyanide-generated half met T2D which first indicated an inability of exogenous ligands to bridge the binuclear copper site in laccase.

  8. Sodium ion effect on silk fibroin conformation characterized by solid-state NMR and generalized 2D NMR NMR correlation

    NASA Astrophysics Data System (ADS)

    Ruan, Qing-Xia; Zhou, Ping

    2008-07-01

    In the present work, we investigated Na + ion effect on the silk fibroin (SF) conformation. Samples are Na +-involved regenerated silk fibroin films. 13C CP-MAS NMR demonstrates that as added [Na +] increases, partial silk fibroin conformation transit from helix-form to β-form at certain Na + ion concentration which is much higher than that in Bombyx mori silkworm gland. The generalized two-dimensional NMR-NMR correlation analysis reveals that silk fibroin undergoes several intermediate states during its conformation transition process as [Na +] increase. The appearance order of the intermediates is followed as: helix and/or random coil → helix-like → β-sheet-like → β-sheet, which is the same as that produced by pH decrease from 6.8 to 4.8 in the resultant regenerated silk fibroin films. The binding sites of Na + to silk fibroin might involve the carbonyl oxygen atom of certain amino acids sequence which could promote the formation of β-sheet conformation. Since the Na +sbnd O bond is weak, the ability of Na + inducing the secondary structure transition is weaker than those of Ca 2+, Cu 2+ and even K +. It is maybe a reason why the sodium content is much lower than potassium in the silkworm gland.

  9. Studies of minute quantities of natural abundance molecules using 2D heteronuclear correlation spectroscopy under 100kHz MAS

    SciTech Connect

    Nishiyama, Y.; Kobayashi, T.; Malon, M.; Singappuli-Arachchige, D.; Slowing, I. I.; Pruski, M.

    2015-02-16

    Two-dimensional 1H{13C} heteronuclear correlation solid-state NMR spectra of naturally abundant solid materials are presented, acquired using the 0.75-mm magic angle spinning (MAS) probe at spinning rates up to 100 kHz. In spite of the miniscule sample volume (290 nL), high-quality HSQC-type spectra of bulk samples as well as surface-bound molecules can be obtained within hours of experimental time. The experiments are compared with those carried out at 40 kHz MAS using a 1.6-mm probe, which offered higher overall sensitivity due to a larger rotor volume. The benefits of ultrafast MAS in such experiments include superior resolution in 1H dimension without resorting to 1H–1H homonuclear RF decoupling, easy optimization, and applicability to mass-limited samples. As a result, the HMQC spectra of surface-bound species can be also acquired under 100 kHz MAS, although the dephasing of transverse magnetization has significant effect on the efficiency transfer under MAS alone.

  10. Studies of minute quantities of natural abundance molecules using 2D heteronuclear correlation spectroscopy under 100kHz MAS

    DOE PAGES

    Nishiyama, Y.; Kobayashi, T.; Malon, M.; ...

    2015-02-16

    Two-dimensional 1H{13C} heteronuclear correlation solid-state NMR spectra of naturally abundant solid materials are presented, acquired using the 0.75-mm magic angle spinning (MAS) probe at spinning rates up to 100 kHz. In spite of the miniscule sample volume (290 nL), high-quality HSQC-type spectra of bulk samples as well as surface-bound molecules can be obtained within hours of experimental time. The experiments are compared with those carried out at 40 kHz MAS using a 1.6-mm probe, which offered higher overall sensitivity due to a larger rotor volume. The benefits of ultrafast MAS in such experiments include superior resolution in 1H dimensionmore » without resorting to 1H–1H homonuclear RF decoupling, easy optimization, and applicability to mass-limited samples. As a result, the HMQC spectra of surface-bound species can be also acquired under 100 kHz MAS, although the dephasing of transverse magnetization has significant effect on the efficiency transfer under MAS alone.« less

  11. CYP2D6 inhibition by fluoxetine, paroxetine, sertraline, and venlafaxine in a crossover study: intraindividual variability and plasma concentration correlations.

    PubMed

    Alfaro, C L; Lam, Y W; Simpson, J; Ereshefsky, L

    2000-01-01

    The authors report the CYP2D6 inhibitory effects of fluoxetine, paroxetine, sertraline, and venlafaxine in an open-label, multiple-dose, crossover design. Twelve CYP2D6 extensive metabolizers were phenotyped, using the dextromethorphan/dextrorphan (DM/DX) urinary ratio, before and after administration of fluoxetine 60 mg (loading dose strategy), paroxetine 20 mg, sertraline 100 mg, and venlafaxine 150 mg. Paroxetine, sertraline, and venlafaxine sequences were randomized with 2-week washouts between treatments; fluoxetine was the last antidepressant (AD) administered. Comparing within groups, baseline DM/DX ratios (0.017) were significantly lower than DM/DX ratios after treatment (DM/DXAD) with fluoxetine (0.313, p < 0.0001) and paroxetine (0.601, p < 0.0001) but not for sertraline (0.026, p = 0.066) or venlafaxine (0.023, p = 0.485). Between groups, DM/DXAD ratios were significantly higher for fluoxetine and paroxetine compared to sertraline and venlafaxine. No differences between DM/DXAD ratios were found for fluoxetine and paroxetine although more subjects phenocopied to PM status after receiving the latter (42% vs. 83%; chi 2 = 4.44, p = 0.049, df = 1). Similarly, no differences between DM/DXAD ratios were found for sertraline and venlafaxine. Of note, the DM/DXAD for 1 subject was much lower after treatment with paroxetine (0.058) compared to fluoxetine (0.490), while another subject exhibited a much lower ratio after treatment with fluoxetine (0.095) compared to paroxetine (0.397). Significant correlations between AD plasma concentration and DM/DXAD were found for paroxetine (r2 = 0.404, p = 0.026) and sertraline (r2 = 0.64, p = 0.002) but not fluoxetine or venlafaxine. In addition, DM/DXAD correlated with baseline isoenzyme activity for paroxetine, sertraline, and venlafaxine groups. These results demonstrate the potent, but variable, CYP2D6 inhibition of fluoxetine and paroxetine compared to sertraline and venlafaxine. CYP2D6 inhibition may be related, in

  12. ERP Correlates of Recognition Memory in Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Massand, Esha; Bowler, Dermot M.; Mottron, Laurent; Hosein, Anthony; Jemel, Boutheina

    2013-01-01

    Recognition memory in autism spectrum disorder (ASD) tends to be undiminished compared to that of typically developing (TD) individuals (Bowler et al. 2007), but it is still unknown whether memory in ASD relies on qualitatively similar or different neurophysiology. We sought to explore the neural activity underlying recognition by employing the…

  13. Neural Correlates of Pragmatic Language Comprehension in Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Tesink, C. M. J. Y.; Buitelaar, J. K.; Petersson, K. M.; van der Gaag, R. J.; Kan, C. C.; Tendolkar, I.; Hagoort, P.

    2009-01-01

    Difficulties with pragmatic aspects of communication are universal across individuals with autism spectrum disorders (ASDs). Here we focused on an aspect of pragmatic language comprehension that is relevant to social interaction in daily life: the integration of speaker characteristics inferred from the voice with the content of a message. Using…

  14. Classification of Acousto-Optic Correlation Signatures of Spread Spectrum Signals Using Artificial Neural Networks

    DTIC Science & Technology

    1989-12-01

    Ohio ’aPw iorlipuab muo i 0I2, AFIT/GE/ENG/89D-10 CLASSIFICATION OF ACOUSTO - OPTIC CORRELATION SIGNATURES OF SPREAD SPECTRUM SIGNALS USING ARTIFICIAL...ENG/89D- 10 CLASSIFICATION OF ACOUSTO - OPTIC CORRELATION SIGNATURES OF SPREAD SPECTRUM SIGNALS USING ARTIFICIAL NEURAL NETWORKS THESIS John W. DeBerry...Captain, USAF AFIT/GE/ENG/89D- 10 Approved for public release; distribution unlimited. AFIT/GE/ENG/89D-10 CLASSIFICATION OF ACOUSTO - OPTIC CORRELATION

  15. A model of adsorption of albumin on the implant surface titanium and titanium modified carbon coatings (MWCNT-EPD). 2D correlation analysis

    NASA Astrophysics Data System (ADS)

    Wesełucha-Birczyńska, Aleksandra; Stodolak-Zych, Ewa; Piś, Wojciech; Długoń, Elżbieta; Benko, Aleksandra; Błażewicz, Marta

    2016-11-01

    Common materials used as orthopedic implants are titanium and its alloys. To improve its compatibility with the environment of a living organism titanium implant surfaces are covered with bioactive layers of MWCNT. During the insertion into a living organism such material is exposed to direct contact with the patient's blood, which includes proteins - eg. albumin. The adsorption of albumin may constitute one of the early stages of implant surface modification serving cell adhesion. An analysis of this phenomenon in terms of the kinetics of deposition of protein on the surface of the implant confirms its biocompatibility in vivo. The proposed working model of the adsorption of albumin allows for choosing the best of time for the protein to form a stable connection with the surface of the titanium implant. Traditional methods of materials engineering and chemistry allow for the obtaining of information about the presence of a protein on the surface (UV-Vis, the wettability). The application of 2D correlation analysis, in turn, gains insight into the dynamics of the changes associated with the deposition of protein (the formation of a uniform layer, the change in conformation). This analysis has allowed for the selection of an optimal time of protein adsorption to the surface of the implant. Better compatibility with the body of the implant provides its modification by introducing layers that accelerate the material-tissue interactions. Such a composition is a layer of carbon nanotubes (MWCNTs) deposited on titanium by the electrophoretic (EPD) method. Using Raman spectroscopy and analyzing the spectra with the 2D correlation method it is possible to gain insight into the molecular structure of this layer. Our studies indicate that albumin in contact with the surface of titanium has obtained stable conformation after 30 min (confirmed by: UV-Vis, Raman). Shifts of the CH2, CH3 stretching bands position as well as an analysis of the amide I band confirms this

  16. Advanced Photoemission Spectroscopy Investigations Correlated with DFT Calculations on the Self-Assembly of 2D Metal Organic Frameworks Nano Thin Films.

    PubMed

    Elzein, Radwan; Chang, Chun-Min; Ponomareva, Inna; Gao, Wen-Yang; Ma, Shengqian; Schlaf, Rudy

    2016-11-16

    Metal-organic frameworks (MOFs) deposited from solution have the potential to form 2-dimensional supramolecular thin films suitable for molecular electronic applications. However, the main challenges lie in achieving selective attachment to the substrate surface, and the integration of organic conductive ligands into the MOF structure to achieve conductivity. The presented results demonstrate that photoemission spectroscopy combined with preparation in a system-attached glovebox can be used to characterize the electronic structure of such systems. The presented results demonstrate that porphyrin-based 2D MOF structures can be produced and that they exhibit similar electronic structure to that of corresponding conventional porphyrin thin films. Porphyrin MOF multilayer thin films were grown on Au substrates prefunctionalized with 4-mercaptopyridine (MP) via incubation in a glovebox, which was connected to an ultrahigh vacuum system outfitted with photoelectron spectroscopy. The thin film growth process was carried out in several sequential steps. In between individual steps the surface was characterized by photoemission spectroscopy to determine the valence bands and evaluate the growth mode of the film. A comprehensive evaluation of X-ray photoemission spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), and inverse photoemission spectroscopy (IPES) data was performed and correlated with density functional theory (DFT) calculations of the density of states (DOS) of the films involved to yield the molecular-level insights into the growth and the electronic properties of MOF-based 2D thin films.

  17. Synthesis, structure and temperature-depended 2D IR correlation spectroscopy of an organo-bismuth benzoate with 1,10-phenanthroline

    NASA Astrophysics Data System (ADS)

    Sun, Yan-Qiong; Zhong, Jie-Cen; Liu, Le-Hui; Qiu, Xing-Tai; Chen, Yi-Ping

    2016-11-01

    An organo-bismuth benzoate with phen as auxiliary ligand, [Bi(phen)(C6H5COO)(C6H4COO)] (1) (phen = 1,10-phenanthroline) has been hydrothermally synthesized from bismuth nitrate, 2-mercaptonbenzoic acid with phen as auxiliary ligand and characterized by single-crystal X-ray diffraction, elemental analyses, PXRD, IR spectra, TG analyses, temperature-depended 2D-IR COS (two-dimensional infrared correlation spectroscopy). Interestingly, benzoate anions in 1 came from the desulfuration reaction of 2-mercaptonbenzoic acid under hydrothermal condition. Compound 1 is a discrete organo-bismuth compound with benzoate and phen ligands. The offset face-to-face π-π stacking interactions and C-H⋯O hydrogen bonds link the isolate complex into a 3D supramolecular network. The temperature-depended 2D-IR COS indicates that the stretching vibrations of Cdbnd C/Cdbnd N of aromatic rings and Cdbnd O bonds are sensitive to the temperature change.

  18. A robust cell counting approach based on a normalized 2D cross-correlation scheme for in-line holographic images.

    PubMed

    Ra, Ho-Kyeong; Kim, Hyungseok; Yoon, Hee Jung; Son, Sang Hyuk; Park, Taejoon; Moon, Sangjun

    2013-09-07

    To achieve the important aims of identifying and marking disease progression, cell counting is crucial for various biological and medical procedures, especially in a Point-Of-Care (POC) setting. In contrast to the conventional manual method of counting cells, a software-based approach provides improved reliability, faster speeds, and greater ease of use. We present a novel software-based approach to count in-line holographic cell images using the calculation of a normalized 2D cross-correlation. This enables fast, computationally-efficient pattern matching between a set of cell library images and the test image. Our evaluation results show that the proposed system is capable of quickly counting cells whilst reliably and accurately following human counting capability. Our novel approach is 5760 times faster than manual counting and provides at least 68% improved accuracy compared to other image processing algorithms.

  19. Correlation between ultrasonic power spectrum and bone density on the heel.

    PubMed

    Xu, Yubing; Xu, Yang; Ding, Zenghui; Chen, Yanyan; Su, Benyue; Ma, Zuchang; Sun, Yi-Ning

    2017-01-01

    The purposes of this paper were to evaluate the correlation between ultrasonic power spectrum and bone density and to extract the effectiveness of parameters from power spectrum for evaluating bone density. A total of 50 persons 24-72years of age were recruited. All study participants underwent bone mineral density (BMD) measurements of the lumbar spine (vertebral levels L1-L4). The participants also underwent calcaneal measurements to determine ultrasonic power spectrum with central frequencies of 0.5MHz. Three parameters from normalized power spectrum, called principle frequency (PF), frequency band (FB), and amplitude for principle frequency (APF), were chosen and be evaluated the correlation with the lumbar spine BMD. The correlation coefficient of PF, FB and APF with BMD was r=-0.48 (p<0.001), r=0.48 (p<0.001), and r=-0.71 (p<0.001), respectively. The results showed that the correlation between APF and BMD was better than the correlation among PF, FB and BMD, and APF have a significant correlation with BMD. In conclusion, the correlations among the parameters of ultrasonic power spectrum and BMD are significant, and especially APF performs better than PF and FB in evaluating bone density of participants. These results suggest that ultrasonic power spectrum may contain substantial information not already contained in BUA and SOS. A multiple regression model including all three QUS variables was somewhat more predictive of BMD than a model including only BUA and SOS.

  20. Effects of Source Correlations on the Spectrum of Radiated Fields

    DTIC Science & Technology

    1990-09-01

    paraxial approximation, with a known result for far-zone radiant intensity of Gaussian Schell - model sources3. Spectral changes on propagation of...33 2.2 The radiation efficiency of planar Gaussian Schell - model sources ............ 34...increase in the source correlation length. Page 40. Figure 2.5: The radiation efficiency of Gaussian Schell - model sources as a function of the rms

  1. Neural correlates of moral reasoning in autism spectrum disorder.

    PubMed

    Schneider, Karla; Pauly, Katharina D; Gossen, Anna; Mevissen, Lea; Michel, Tanja M; Gur, Ruben C; Schneider, Frank; Habel, Ute

    2013-08-01

    In our study, we tried to clarify whether patients with autism spectrum disorder (ASD) reveal different moral decision patterns as compared to healthy subjects and whether common social interaction difficulties in ASD are reflected in altered brain activation during different aspects of moral reasoning. 28 patients with high-functioning ASD and 28 healthy subjects matched for gender, age and education took part in an event-related functional magnetic resonance imaging study. Participants were confronted with textual dilemma situations followed by proposed solutions to which they could agree or disagree. On a neural level, moral decision making was associated with activation in anterior medial prefrontal regions, the temporo-parietal junction and the precuneus for both groups. However, while patients and healthy controls did not exhibit significant behavioral differences, ASD patients showed decreased activation in limbic regions, particularly the amygdala, as well as increased activation in the anterior and the posterior cingulate gyrus during moral reasoning. Alterations of brain activation in patients might thus indicate specific impairments in empathy. However, activation increases in brain regions associated with the 'default mode network' and self-referential cognition also provide evidence for an altered way of patients' cerebral processing with regard to decision making based on social information.

  2. Measuring peptide mass spectrum correlation using the quantum Grover algorithm.

    PubMed

    Choo, Keng Wah

    2007-03-01

    We investigated the use of the quantum Grover algorithm in the mass-spectrometry-based protein identification process. The approach coded the mass spectra on a quantum register and uses the Grover search algorithm for searching multiple solutions to find matches from a database. Measurement of the fidelity between the input and final states was used to quantify the similarity between the experimental and theoretical spectra. The optimal number of iteration is proven to be pi/4sqrt[N/k] , where k refers to the number of marked states. We found that one iteration is sufficient for the search if we let more that 62% of the N states be marked states. By measuring the fidelity after only one iteration of Grover search, we discovered that it resembles that of the correlation-based measurement used in the existing protein identification software. We concluded that the quantum Grover algorithm can be adapted for a correlation-based mass spectra database search, provided that decoherence can be kept to a minimum.

  3. Correlation between 3D microstructural and 2D histomorphometric properties of subchondral bone with healthy and degenerative cartilage of the knee joint.

    PubMed

    Lahm, Andreas; Kasch, Richard; Spank, Heiko; Erggelet, Christoph; Esser, Jan; Merk, Harry; Mrosek, Eike

    2014-11-01

    Cartilage degeneration of the knee joint is considered to be a largely mechanically driven process. We conducted a microstructural and histomorphometric analysis of subchondral bone samples of intact cartilage and in samples with early and higher- grade arthritic degeneration to compare the different states and correlate the findings with the condition of hyaline cartilage. These findings will enable us to evaluate changes in biomechanical properties of subchondral bone during the evolution of arthritic degeneration, for which bone density alone is an insufficient parameter. From a continuous series of 80 patients undergoing implantation of total knee endoprosthesis 30 osteochondral samples with lesions macroscopically classified as ICRS grade 1b (group A) and 30 samples with ICRS grade 3a or 3b lesions (group B) were taken. The bone samples were assessed by 2D histomorphometry (semiautomatic image analysis system) and 3D microstructural analysis (high-resolution micro-CT system). The cartilage was examined using the semiquantitative real-time PCR gene expression of collagen type I and II and aggrecan. Both histomorphometry and microstructural and biomechanical analysis of subchondral bone in groups A and B consistently revealed progressive changes of both bone and cartilage compared with healthy controls. The severity of cartilage degeneration as assessed by RT PCR was significantly correlated with BV/TV (Bone Volume Fraction), Tb.Th (Trabecular Thickness) showed a slight increase. Tb.N (Trabecular Number), Tb.Sp (Trabecular separation) SMI (Structure Model Index), Conn.D (Connectivity Density) and DA (Degree of Anisotropy) were inversely correlated. We saw sclerotic transformation and phagocytic reticulum cells. Bone volume fraction decreased with an increasing distance from the cartilage with the differences compared with healthy controls becoming greater in more advanced cartilage damage. The density of subchondral bone alone is considered an unreliable

  4. The 2dF Galaxy Redshift Survey: correlation with the ROSAT-ESO flux-limited X-ray galaxy cluster survey

    NASA Astrophysics Data System (ADS)

    Hilton, Matt; Collins, Chris; De Propris, Roberto; Baldry, Ivan K.; Baugh, Carlton M.; Bland-Hawthorn, Joss; Bridges, Terry; Cannon, Russell; Cole, Shaun; Colless, Matthew; Couch, Warrick J.; Dalton, Gavin B.; Driver, Simon P.; Efstathiou, George; Ellis, Richard S.; Frenk, Carlos S.; Glazebrook, Karl; Jackson, Carole A.; Lahav, Ofer; Lewis, Ian; Lumsden, Stuart; Maddox, Steve J.; Madgwick, Darren; Norberg, Peder; Peacock, John A.; Peterson, Bruce A.; Sutherland, Will; Taylor, Keith

    2005-10-01

    The ROSAT-European Southern Observatory (ESO) flux-limited X-ray (REFLEX) galaxy cluster survey and the Two-degree Field Galaxy Redshift Survey (2dFGRS), respectively, comprise the largest, homogeneous X-ray selected cluster catalogue and completed galaxy redshift survey. In this work, we combine these two outstanding data sets in order to study the effect of the large-scale cluster environment, as traced by X-ray luminosity, on the properties of the cluster member galaxies. We measure the LX-σr relation from the correlated data set and find it to be consistent with recent results found in the literature. Using a sample of 19 clusters with LX>= 0.36 × 1044 erg s-1 in the 0.1-2.4 keV band, and 49 clusters with lower X-ray luminosity, we find that the fraction of early spectral type (η<=-1.4), passively evolving galaxies is significantly higher in the high-LX sample within R200. We extend the investigation to include composite bJ cluster luminosity functions, and find that the characteristic magnitude of the Schechter-function fit to the early-type luminosity function is fainter for the high-LX sample compared to the low-LX sample (ΔM*= 0.58 +/- 0.14). This seems to be driven by a deficit of such galaxies with MbJ~-21. In contrast, we find no significant differences between the luminosity functions of star-forming, late-type galaxies. We believe these results are consistent with a scenario in which the high-LX clusters are more dynamically evolved systems than the low-LX clusters.

  5. Incidence and Behavioral Correlates of Epileptiform Abnormalities in Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Mulligan, Caitlin K.; Trauner, Doris A.

    2014-01-01

    Autism spectrum disorders (ASD) are associated with an increased incidence of epilepsy and of epileptiform discharges on electroencephalograms. It is unknown whether epileptiform discharges correlate with symptoms of ASD. We completed a retrospective chart review of 101 patients with ASD who had overnight electroencephalograms. We looked for a…

  6. Prevalence and Correlates of Postsecondary Residential Status among Young Adults with an Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Anderson, Kristy A.; Shattuck, Paul T.; Cooper, Benjamin P.; Roux, Anne M.; Wagner, Mary

    2014-01-01

    This study examined the prevalence and correlates of three living arrangements (with a parent or guardian, independently or with a roommate, or in a supervised setting) among a nationally representative sample of postsecondary young adults with an autism spectrum disorder. We assessed living arrangements since leaving high school. Compared with…

  7. Sleep Problems and Their Correlates and Comorbid Psychopathology of Children with Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Park, Subin; Cho, Soo-Churl; Cho, In Hee; Kim, Boong-Nyun; Kim, Jae-Won; Shin, Min-Sup; Chung, Un-Sun; Park, Tae-Won; Son, Jung-Woo; Yoo, Hee Jeong

    2012-01-01

    This study examined sleep problems and their correlates and comorbid psychopathology in children with autism spectrum disorders (ASDs). Participants consisted of 166 ASD children and 111 unaffected siblings aged 4-15 years. Parents completed a self-administered child sleep questionnaire. Of the children with ASDs, 47.0% (78/166) had at least one…

  8. Hoarding in Youth with Autism Spectrum Disorders and Anxiety: Incidence, Clinical Correlates, and Behavioral Treatment Response

    ERIC Educational Resources Information Center

    Storch, Eric A.; Nadeau, Joshua M.; Johnco, Carly; Timpano, Kiara; McBride, Nicole; Mutch, P. Jane; Lewin, Adam B.; Murphy, Tanya K.

    2016-01-01

    This study examined the nature and correlates of hoarding among youth with autism spectrum disorders (ASD). Forty children with ASD and a comorbid anxiety disorder were administered a battery of clinician-administered measures assessing presence of psychiatric disorders and anxiety severity. Parents completed questionnaires related to child…

  9. Demographic and Clinical Correlates of Autism Symptom Domains and Autism Spectrum Diagnosis

    ERIC Educational Resources Information Center

    Frazier, Thomas W.; Youngstrom, Eric A.; Embacher, Rebecca; Hardan, Antonio Y.; Constantino, John N.; Law, Paul; Findling, Robert L.; Eng, Charis

    2014-01-01

    Demographic and clinical factors may influence assessment of autism symptoms. This study evaluated these correlates and also examined whether social communication and interaction and restricted/repetitive behavior provided unique prediction of autism spectrum disorder diagnosis. We analyzed data from 7352 siblings included in the Interactive…

  10. Correlation of pulsar radio emission spectrum with peculiarities of particle acceleration in a polar gap

    SciTech Connect

    Kontorovich, V. M. Flanchik, A. B.

    2013-01-15

    The analytical expression for the frequency of radio emission intensity maximum in pulsars with free electron emission from the stellar surface has been found. Peculiarities of the electron acceleration in a polar gap are considered. The correlation between the high-frequency cutoff and low-frequency turnover in the radio emission spectrum of pulsars known from observations has been explained.

  11. Prevalence and Correlates of Educational Intervention Utilization among Children with Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Bilaver, Lucy A.; Cushing, Lisa S.; Cutler, Ann T.

    2016-01-01

    This study examined the prevalence and correlates of educational intervention utilization among U.S. preschool aged children with autism spectrum disorder (ASD) prior to recent policy changes. The analysis was based on a nationally representative longitudinal survey of children receiving special education services during the 2003-2004 school year.…

  12. Efficient 2D MRI relaxometry using compressed sensing

    NASA Astrophysics Data System (ADS)

    Bai, Ruiliang; Cloninger, Alexander; Czaja, Wojciech; Basser, Peter J.

    2015-06-01

    Potential applications of 2D relaxation spectrum NMR and MRI to characterize complex water dynamics (e.g., compartmental exchange) in biology and other disciplines have increased in recent years. However, the large amount of data and long MR acquisition times required for conventional 2D MR relaxometry limits its applicability for in vivo preclinical and clinical MRI. We present a new MR pipeline for 2D relaxometry that incorporates compressed sensing (CS) as a means to vastly reduce the amount of 2D relaxation data needed for material and tissue characterization without compromising data quality. Unlike the conventional CS reconstruction in the Fourier space (k-space), the proposed CS algorithm is directly applied onto the Laplace space (the joint 2D relaxation data) without compressing k-space to reduce the amount of data required for 2D relaxation spectra. This framework is validated using synthetic data, with NMR data acquired in a well-characterized urea/water phantom, and on fixed porcine spinal cord tissue. The quality of the CS-reconstructed spectra was comparable to that of the conventional 2D relaxation spectra, as assessed using global correlation, local contrast between peaks, peak amplitude and relaxation parameters, etc. This result brings this important type of contrast closer to being realized in preclinical, clinical, and other applications.

  13. Nano-spatial parameters from 3D to 2D lattice dimensionality by organic variant in [ZnCl4]- [R]+ hybrid materials: Structure, architecture-lattice dimensionality, microscopy, optical Eg and PL correlations

    NASA Astrophysics Data System (ADS)

    Kumar, Ajit; Verma, Sanjay K.; Alvi, P. A.; Jasrotia, Dinesh

    2016-04-01

    The nanospatial morphological features of [ZnCl]- [C5H4NCH3]+ hybrid derivative depicts 28 nm granular size and 3D spreader shape packing pattern as analyzed by FESEM and single crystal XRD structural studies. The organic moiety connect the inorganic components through N-H+…Cl- hydrogen bond to form a hybrid composite, the replacement of organic derivatives from 2-methylpyridine to 2-Amino-5-choloropyridine results the increase in granular size from 28nm to 60nm and unit cell packing pattern from 3D-2D lattice dimensionality along ac plane. The change in optical energy direct band gap value from 3.01eV for [ZnCl]- [C5H4NCH3]+ (HM1) to 3.42eV for [ZnCl]- [C5H5ClN2]+ (HM2) indicates the role of organic moiety in optical properties of hybrid materials. The photoluminescence emission spectra is observed in the wavelength range of 370 to 600 nm with maximum peak intensity of 9.66a.u. at 438 nm for (HM1) and 370 to 600 nm with max peak intensity of 9.91 a.u. at 442 nm for (HM2), indicating that the emission spectra lies in visible range. PL excitation spectra depicts the maximum excitation intensity [9.8] at 245.5 nm for (HM1) and its value of 9.9 a.u. at 294 nm, specify the excitation spectra lies in UV range. Photoluminescence excitation spectra is observed in the wavelength range of 280 to 350 nm with maximum peak intensity of 9.4 a.u. at 285.5 nm and 9.9 a.u. at 294 and 297 nm, indicating excitation in the UV spectrum. Single crystal growth process and detailed physiochemical characterization such as XRD, FESEM image analysis photoluminescence property reveals the structure stability with non-covalent interactions, lattice dimensionality (3D-2D) correlations interweaving into the design of inorganic-organic hybrid materials.

  14. Trajectories and correlates of special education supports for youth with autism spectrum disorder and psychiatric comparisons.

    PubMed

    Spaulding, Christine J; Lerner, Matthew D; Gadow, Kenneth D

    2017-05-01

    Relatively little is known about patterns of school-based supportive services for youth with autism spectrum disorder. This study describes these supportive services and their correlates, both cross-sectionally and retrospectively, in a large sample ( N = 283) of 6- to 18- year-old youth. To assess whether special education designation and classroom placement patterns were peculiar to autism spectrum disorder, we also conducted analyses comparing youth with autism spectrum disorder to those with other psychiatric diagnoses ( N = 1088). In higher grades, the relative quantity of three common supportive services received by youth with autism spectrum disorder decreased, while total supportive service quantity remained stable over time. Youth with autism spectrum disorder were more likely to receive a special education designation and were placed in less inclusive classroom settings than youth with other psychiatric diagnoses. These findings suggest that as youth with autism spectrum disorder reach higher grades, changes in service provision occur in terms of both time and quantity.

  15. Demographic and clinical correlates of autism symptom domains and autism spectrum diagnosis.

    PubMed

    Frazier, Thomas W; Youngstrom, Eric A; Embacher, Rebecca; Hardan, Antonio Y; Constantino, John N; Law, Paul; Findling, Robert L; Eng, Charis

    2014-07-01

    Demographic and clinical factors may influence assessment of autism symptoms. This study evaluated these correlates and also examined whether social communication and interaction and restricted/repetitive behavior provided unique prediction of autism spectrum disorder diagnosis. We analyzed data from 7352 siblings included in the Interactive Autism Network registry. Social communication and interaction and restricted/repetitive behavior symptoms were obtained using caregiver-reports on the Social Responsiveness Scale. Demographic and clinical correlates were covariates in regression models predicting social communication and interaction and restricted/repetitive behavior symptoms. Logistic regression and receiver operating characteristic curve analyses evaluated the incremental validity of social communication and interaction and restricted/repetitive behavior domains over and above global autism symptoms. Autism spectrum disorder diagnosis was the strongest correlate of caregiver-reported social communication and interaction and restricted/repetitive behavior symptoms. The presence of comorbid diagnoses also increased symptom levels. Social communication and interaction and restricted/repetitive behavior symptoms provided significant, but modest, incremental validity in predicting diagnosis beyond global autism symptoms. These findings suggest that autism spectrum disorder diagnosis is by far the largest determinant of quantitatively measured autism symptoms. Externalizing (attention deficit hyperactivity disorder) and internalizing (anxiety) behavior, low cognitive ability, and demographic factors may confound caregiver-report of autism symptoms, potentially necessitating a continuous norming approach to the revision of symptom measures. Social communication and interaction and restricted/repetitive behavior symptoms may provide incremental validity in the diagnosis of autism spectrum disorder.

  16. The roles of carbohydrates, proteins and lipids in the process of aggregation of natural marine organic matter investigated by means of 2D correlation spectroscopy applied to infrared spectra.

    PubMed

    Mecozzi, Mauro; Pietrantonio, Eva; Pietroletti, Marco

    2009-01-01

    In this paper the marine organic matter soluble in an alkaline medium called extractable humic substance (EHS), was extracted from three sediment samples of Tyrrhenian Sea and separated by precipitation at pH 2 in the two fractions of fulvic acids (FAs) and humic acids (HAs). FAs were further fractionated in seven sub-samples of different molecular weight (mw) by means of seven different ultrafiltration membranes operating in the range between mw<1 kDa and mw>100 kDa. Then the qualitative composition of each sample of fractionated FAs and HAs was studied by means of one-dimensional Fourier transform infrared spectroscopy in reflectance mode (FTIR-DRIFT) and by two-dimensional (2D) correlation spectroscopy both in wavelength-wavelength (WW) and in sample-sample (SS) mode. The application of 2D correlation WW spectroscopy allows to elucidate the different roles played by carbohydrates and proteins with respect to some lipid compounds such as fatty acids and ester fatty acids during the process of aggregate formations from mw approximately 1 kDa to higher size aggregates. In addition, 2D correlation WW spectroscopy allows to observe some peculiar interactions between carbohydrates and proteins in the formation of EHS aggregates, interactions which vary from a sample to another sample. The results of 2D correlation SS spectroscopy confirm the general evidences obtained by 2D WW spectroscopy and moreover, they also describe the formation of EHS aggregates as a complex process where evolutionary links and connectivity between aggregates of neighbour molecular size ranges are not evident. Two-dimensional correlation spectroscopy applied to FTIR spectroscopy shows to be a powerful tool for the investigation of the mechanisms involved in EHS aggregation because it supports the acquisition of structural information which sometimes can be hardly obtained by one-dimensional FTIR spectroscopy.

  17. The roles of carbohydrates, proteins and lipids in the process of aggregation of natural marine organic matter investigated by means of 2D correlation spectroscopy applied to infrared spectra

    NASA Astrophysics Data System (ADS)

    Mecozzi, Mauro; Pietrantonio, Eva; Pietroletti, Marco

    2009-01-01

    In this paper the marine organic matter soluble in an alkaline medium called extractable humic substance (EHS), was extracted from three sediment samples of Tyrrhenian Sea and separated by precipitation at pH 2 in the two fractions of fulvic acids (FAs) and humic acids (HAs). FAs were further fractionated in seven sub-samples of different molecular weight (mw) by means of seven different ultrafiltration membranes operating in the range between mw < 1 kDa and mw > 100 kDa. Then the qualitative composition of each sample of fractionated FAs and HAs was studied by means of one-dimensional Fourier transform infrared spectroscopy in reflectance mode (FTIR-DRIFT) and by two-dimensional (2D) correlation spectroscopy both in wavelength-wavelength (WW) and in sample-sample (SS) mode. The application of 2D correlation WW spectroscopy allows to elucidate the different roles played by carbohydrates and proteins with respect to some lipid compounds such as fatty acids and ester fatty acids during the process of aggregate formations from mw ˜1 kDa to higher size aggregates. In addition, 2D correlation WW spectroscopy allows to observe some peculiar interactions between carbohydrates and proteins in the formation of EHS aggregates, interactions which vary from a sample to another sample. The results of 2D correlation SS spectroscopy confirm the general evidences obtained by 2D WW spectroscopy and moreover, they also describe the formation of EHS aggregates as a complex process where evolutionary links and connectivity between aggregates of neighbour molecular size ranges are not evident. Two-dimensional correlation spectroscopy applied to FTIR spectroscopy shows to be a powerful tool for the investigation of the mechanisms involved in EHS aggregation because it supports the acquisition of structural information which sometimes can be hardly obtained by one-dimensional FTIR spectroscopy.

  18. Physical activity, sedentary behavior and their correlates in children with Autism Spectrum Disorder: A systematic review

    PubMed Central

    Downing, Katherine; Rinehart, Nicole J.; Barnett, Lisa M.; May, Tamara; McGillivray, Jane A.; Papadopoulos, Nicole V.; Skouteris, Helen; Timperio, Anna

    2017-01-01

    Autism Spectrum Disorder affects up to 2.5% of children and is associated with harmful health outcomes (e.g. obesity). Low levels of physical activity and high levels of sedentary behaviors may contribute to harmful health outcomes. To systematically review the prevalence and correlates of physical activity and sedentary behaviors in children with Autism Spectrum Disorder, electronic databases (PsycINFO, SPORTDiscus, EMBASE, Medline) were searched from inception to November 2015. The review was registered with PROSPERO (CRD42014013849). Peer-reviewed, English language studies were included. Two reviewers screened potentially relevant articles. Outcomes of interest were physical activity and sedentary behaviour levels and their potential correlates. Data were collected and analysed in 2015. Of 35 included studies, 15 reported physical activity prevalence, 10 reported physical activity correlates, 18 reported sedentary behavior prevalence, and 10 reported sedentary behavior correlates. Estimates of children’s physical activity (34–166 mins/day, average 86 mins/day) and sedentary behavior (126–558 mins/day in screen time, average 271 mins/day; 428–750 mins/day in total sedentary behavior, average 479 mins/day) varied across studies. Age was consistently inversely associated, and sex inconsistently associated with physical activity. Age and sex were inconsistently associated with sedentary behavior. Sample sizes were small. All but one of the studies were classified as having high risk of bias. Few correlates have been reported in sufficient studies to provide overall estimates of associations. Potential correlates in the physical environment remain largely unexamined. This review highlights varying levels of physical activity and sedentary behavior in children with Autism Spectrum Disorder. Research is needed to consistently identify the correlates of these behaviors. There is a critical need for interventions to support healthy levels of these behaviors. PMID

  19. Physical activity, sedentary behavior and their correlates in children with Autism Spectrum Disorder: A systematic review.

    PubMed

    Jones, Rachel A; Downing, Katherine; Rinehart, Nicole J; Barnett, Lisa M; May, Tamara; McGillivray, Jane A; Papadopoulos, Nicole V; Skouteris, Helen; Timperio, Anna; Hinkley, Trina

    2017-01-01

    Autism Spectrum Disorder affects up to 2.5% of children and is associated with harmful health outcomes (e.g. obesity). Low levels of physical activity and high levels of sedentary behaviors may contribute to harmful health outcomes. To systematically review the prevalence and correlates of physical activity and sedentary behaviors in children with Autism Spectrum Disorder, electronic databases (PsycINFO, SPORTDiscus, EMBASE, Medline) were searched from inception to November 2015. The review was registered with PROSPERO (CRD42014013849). Peer-reviewed, English language studies were included. Two reviewers screened potentially relevant articles. Outcomes of interest were physical activity and sedentary behaviour levels and their potential correlates. Data were collected and analysed in 2015. Of 35 included studies, 15 reported physical activity prevalence, 10 reported physical activity correlates, 18 reported sedentary behavior prevalence, and 10 reported sedentary behavior correlates. Estimates of children's physical activity (34-166 mins/day, average 86 mins/day) and sedentary behavior (126-558 mins/day in screen time, average 271 mins/day; 428-750 mins/day in total sedentary behavior, average 479 mins/day) varied across studies. Age was consistently inversely associated, and sex inconsistently associated with physical activity. Age and sex were inconsistently associated with sedentary behavior. Sample sizes were small. All but one of the studies were classified as having high risk of bias. Few correlates have been reported in sufficient studies to provide overall estimates of associations. Potential correlates in the physical environment remain largely unexamined. This review highlights varying levels of physical activity and sedentary behavior in children with Autism Spectrum Disorder. Research is needed to consistently identify the correlates of these behaviors. There is a critical need for interventions to support healthy levels of these behaviors.

  20. Time domain averaging and correlation-based improved spectrum sensing method for cognitive radio

    NASA Astrophysics Data System (ADS)

    Li, Shenghong; Bi, Guoan

    2014-12-01

    Based on the combination of time domain averaging and correlation, we propose an effective time domain averaging and correlation-based spectrum sensing (TDA-C-SS) method used in very low signal-to-noise ratio (SNR) environments. With the assumption that the received signals from the primary users are deterministic, the proposed TDA-C-SS method processes the received samples by a time averaging operation to improve the SNR. Correlation operation is then performed with a correlation matrix to determine the existence of the primary signal in the received samples. The TDA-C-SS method does not need any prior information on the received samples and the associated noise power to achieve improved sensing performance. Simulation results are presented to show the effectiveness of the proposed TDA-C-SS method.

  1. Phonon spectrum and correlations in a transonic flow of an atomic Bose gas

    NASA Astrophysics Data System (ADS)

    Michel, Florent; Coupechoux, Jean-François; Parentani, Renaud

    2016-10-01

    Motivated by a recent experiment of J. Steinhauer, we reconsider the spectrum and the correlations of the phonons spontaneously emitted in stationary transonic flows. The latter are described by "waterfall" configurations which form a one-parameter family of stable flows. For parameters close to their experimental values, in spite of high gradients near the sonic horizon, the spectrum is accurately Planckian in the relevant frequency domain, where the temperature differs from the relativistic prediction by less than 10%. We then study the density correlations across the horizon and the nonseparable character of the final state. We show that the relativistic expressions provide accurate approximations when the initial temperature is not too high. We also show that the phases of the scattering coefficients introduce a finite shift of the location of the correlations which has so far been overlooked. This shift is due to the asymmetry of the flow across the horizon, and persists in the dispersionless regime. Finally we show how the formation of the sonic horizon modifies both local and nonlocal density correlations.

  2. Time and spectrum-resolving multiphoton correlator for 300–900 nm

    SciTech Connect

    Johnsen, Kelsey D.; Thibault, Marilyne; Jennewein, Thomas; Kolenderski, Piotr; Scarcella, Carmelo; Tosi, Alberto

    2014-10-14

    We demonstrate a single-photon sensitive spectrometer in the visible range, which allows us to perform time-resolved and multi-photon spectral correlation measurements at room temperature. It is based on a monochromator composed of two gratings, collimation optics, and an array of single photon avalanche diodes. The time resolution can reach 110 ps and the spectral resolution is 2 nm/pixel, limited by the design of the monochromator. This technique can easily be combined with commercial monochromators and can be useful for joint spectrum measurements of two photons emitted in the process of parametric down conversion, as well as time-resolved spectrum measurements in optical coherence tomography or medical physics applications.

  3. Automation and validation of micronucleus detection in the 3D EpiDerm™ human reconstructed skin assay and correlation with 2D dose responses

    PubMed Central

    Chapman, K. E.; Thomas, A. D.; Jenkins, G. J. S.

    2014-01-01

    Recent restrictions on the testing of cosmetic ingredients in animals have resulted in the need to test the genotoxic potential of chemicals exclusively in vitro prior to licensing. However, as current in vitro tests produce some misleading positive results, sole reliance on such tests could prevent some chemicals with safe or beneficial exposure levels from being marketed. The 3D human reconstructed skin micronucleus (RSMN) assay is a promising new in vitro approach designed to assess genotoxicity of dermally applied compounds. The assay utilises a highly differentiated in vitro model of the human epidermis. For the first time, we have applied automated micronucleus detection to this assay using MetaSystems Metafer Slide Scanning Platform (Metafer), demonstrating concordance with manual scoring. The RSMN assay’s fixation protocol was found to be compatible with the Metafer, providing a considerably shorter alternative to the recommended Metafer protocol. Lowest observed genotoxic effect levels (LOGELs) were observed for mitomycin-C at 4.8 µg/ml and methyl methanesulfonate (MMS) at 1750 µg/ml when applied topically to the skin surface. In-medium dosing with MMS produced a LOGEL of 20 µg/ml, which was very similar to the topical LOGEL when considering the total mass of MMS added. Comparisons between 3D medium and 2D LOGELs resulted in a 7-fold difference in total mass of MMS applied to each system, suggesting a protective function of the 3D microarchitecture. Interestingly, hydrogen peroxide (H2O2), a positive clastogen in 2D systems, tested negative in this assay. A non-genotoxic carcinogen, methyl carbamate, produced negative results, as expected. We also demonstrated expression of the DNA repair protein N-methylpurine-DNA glycosylase in EpiDerm™. Our preliminary validation here demonstrates that the RSMN assay may be a valuable follow-up to the current in vitro test battery, and together with its automation, could contribute to minimising unnecessary in

  4. Prediction of {sup 2}D Rydberg energy levels of {sup 6}Li and {sup 7}Li based on very accurate quantum mechanical calculations performed with explicitly correlated Gaussian functions

    SciTech Connect

    Bubin, Sergiy; Sharkey, Keeper L.; Adamowicz, Ludwik

    2013-04-28

    Very accurate variational nonrelativistic finite-nuclear-mass calculations employing all-electron explicitly correlated Gaussian basis functions are carried out for six Rydberg {sup 2}D states (1s{sup 2}nd, n= 6, Horizontal-Ellipsis , 11) of the {sup 7}Li and {sup 6}Li isotopes. The exponential parameters of the Gaussian functions are optimized using the variational method with the aid of the analytical energy gradient determined with respect to these parameters. The experimental results for the lower states (n= 3, Horizontal-Ellipsis , 6) and the calculated results for the higher states (n= 7, Horizontal-Ellipsis , 11) fitted with quantum-defect-like formulas are used to predict the energies of {sup 2}D 1s{sup 2}nd states for {sup 7}Li and {sup 6}Li with n up to 30.

  5. Correlation of CpG Island Methylation of the Cytochrome P450 2E1/2D6 Genes with Liver Injury Induced by Anti-Tuberculosis Drugs: A Nested Case-Control Study

    PubMed Central

    Zhang, Jinling; Zhu, Xuebin; Li, Yuhong; Zhu, Lingyan; Li, Shiming; Zheng, Guoying; Ren, Qi; Xiao, Yonghong; Feng, Fumin

    2016-01-01

    This study investigated the role of CpG island methylation of the CYP2E1 and CYP2D6 genes in liver injury induced by anti-TB drugs from an epigenetic perspective in a Chinese cohort. A 1:1 matched nested case-control study design was applied. Pulmonary tuberculosis (TB) patients, who underwent standard anti-TB therapy and developed liver injury were defined as cases, while those who did not develop liver injury were defined as control. The two groups were matched in terms of sex, treatment regimen, and age. In 114 pairs of cases, CpG island methylation levels of the CYP2E1 and CYP2D6 genes in plasma cell-free DNA were found to be significantly correlated with the occurrence of anti-TB drug-induced liver injury (ADLI), with odds ratio (OR) values of 2.429 and 3.500, respectively (p < 0.01). Moreover, through multivariate logistic regression analysis, CpG island methylation of the CYP2E1 and CYP2D6 genes in plasma cell-free DNA were found to be significantly correlated with the occurrence of ADLI, with adjusted OR values of 4.390 (95% confidence interval (CI): 1.982–9.724) and 9.193 (95% CI: 3.624–25.888), respectively (p < 0.001). These results suggest that aberrantly elevated methylation of CpG islands of the CYP2E1 and CYP2D6 genes in plasma cell-free DNA may increase the risk of ADLI in Chinese TB patients. PMID:27490558

  6. Application of interferential correlation of spectrum to the detection of atmospheric pollutants

    NASA Technical Reports Server (NTRS)

    Fortunato, G.

    1979-01-01

    The general correlation principles for spectra and spectra derivatives are studied by using the Fourier transform of the spectral distribution of energy from a source illuminating a double beam interferometer with transverse splitting by dividing luminance. In this correlation technique, the use of such an interferometer has the advantage of greater luminosity as compared with a slit spectrometer. However, the correlation example indicates that it is necessary to adapt the correlator to the particular case considered, in order to obtain the best gain in the signal to noise ratio. In the case of sulfur dioxide detection, a very simple mounting which could be used in some interesting industrial applications was developed. This mounting can be used each time that the substance to be analyzed has a quasi-periodic absorption spectrum: in particular this is often the case with absorption spectra of gases, and a mounting identical to the one described for sulfur dioxide proved to be effective in the detection of nitrogen oxides.

  7. Lensing corrections to features in the angular two-point correlation function and power spectrum

    SciTech Connect

    LoVerde, Marilena; Hui, Lam; Gaztanaga, Enrique

    2008-01-15

    It is well known that magnification bias, the modulation of galaxy or quasar source counts by gravitational lensing, can change the observed angular correlation function. We investigate magnification-induced changes to the shape of the observed correlation function w({theta}), and the angular power spectrum C{sub l}, paying special attention to the matter-radiation equality peak and the baryon wiggles. Lensing effectively mixes the correlation function of the source galaxies with that of the matter correlation at the lower redshifts of the lenses distorting the observed correlation function. We quantify how the lensing corrections depend on the width of the selection function, the galaxy bias b, and the number count slope s. The lensing correction increases with redshift and larger corrections are present for sources with steep number count slopes and/or broad redshift distributions. The most drastic changes to C{sub l} occur for measurements at high redshifts (z > or approx. 1.5) and low multipole moment (l < or approx. 100). For the source distributions we consider, magnification bias can shift the location of the matter-radiation equality scale by 1%-6% at z{approx}1.5 and by z{approx}3.5 the shift can be as large as 30%. The baryon bump in {theta}{sup 2}w({theta}) is shifted by < or approx. 1% and the width is typically increased by {approx}10%. Shifts of > or approx. 0.5% and broadening > or approx. 20% occur only for very broad selection functions and/or galaxies with (5s-2)/b > or approx. 2. However, near the baryon bump the magnification correction is not constant but is a gently varying function which depends on the source population. Depending on how the w({theta}) data is fitted, this correction may need to be accounted for when using the baryon acoustic scale for precision cosmology.

  8. Investigating the Microstructural Correlation of White Matter in Autism Spectrum Disorder.

    PubMed

    Dean, Douglas C; Travers, Brittany G; Adluru, Nagesh; Tromp, Do P M; Destiche, Daniel J; Samsin, Danica; Prigge, Molly B; Zielinski, Brandon A; Fletcher, P Thomas; Anderson, Jeffrey S; Froehlich, Alyson L; Bigler, Erin D; Lange, Nicholas; Lainhart, Janet E; Alexander, Andrew L

    2016-06-01

    White matter microstructure forms a complex and dynamical system that is critical for efficient and synchronized brain function. Neuroimaging findings in children with autism spectrum disorder (ASD) suggest this condition is associated with altered white matter microstructure, which may lead to atypical macroscale brain connectivity. In this study, we used diffusion tensor imaging measures to examine the extent that white matter tracts are interrelated within ASD and typical development. We assessed the strength of inter-regional white matter correlations between typically developing and ASD diagnosed individuals. Using hierarchical clustering analysis, clustering patterns of the pairwise white matter correlations were constructed and revealed to be different between the two groups. Additionally, we explored the use of graph theory analysis to examine the characteristics of the patterns formed by inter-regional white matter correlations and compared these properties between ASD and typical development. We demonstrate that the ASD sample has significantly less coherence in white matter microstructure across the brain compared to that in the typical development sample. The ASD group also presented altered topological characteristics, which may implicate less efficient brain networking in ASD. These findings highlight the potential of graph theory based network characteristics to describe the underlying networks as measured by diffusion magnetic resonance imaging and furthermore indicates that ASD may be associated with altered brain network characteristics. Our findings are consistent with those of a growing number of studies and hypotheses that have suggested disrupted brain connectivity in ASD.

  9. Regularized cosmological power spectrum and correlation function in modified gravity models

    NASA Astrophysics Data System (ADS)

    Taruya, Atsushi; Nishimichi, Takahiro; Bernardeau, Francis; Hiramatsu, Takashi; Koyama, Kazuya

    2014-12-01

    Based on the multipoint propagator expansion, we present resummed perturbative calculations for cosmological power spectra and correlation functions in the context of modified gravity. In a wide class of modified gravity models that have a screening mechanism to recover general relativity (GR) on small scales, we apply the eikonal approximation to derive the governing equation for resummed propagator that partly includes the nonperturbative effect in the high-k limit. The resultant propagator in the high-k limit contains the new corrections arising from the screening mechanism as well as the standard exponential damping. We explicitly derive the expression for new high-k contributions in specific modified gravity models, and find that in the case of f (R ) gravity for a currently constrained model parameter, the corrections are basically of the subleading order and can be neglected. Thus, in f (R ) gravity, similarly to the GR case, we can analytically construct the regularized propagator that reproduces both the resummed high-k behavior and the low-k results computed with standard perturbation theory, consistently taking account of the nonlinear modification of gravity valid at large scales. With the regularized multipoint propagators, we give predictions for power spectrum and correlation function at one-loop order, and compare those with N -body simulations in f (R ) gravity model. As an important application, we also discuss the redshift-space distortions and compute the anisotropic power spectra and correlation functions.

  10. Increased homocysteine levels correlate with the communication deficit in children with autism spectrum disorder.

    PubMed

    Puig-Alcaraz, Carmen; Fuentes-Albero, Milagros; Calderón, Jesús; Garrote, Dolores; Cauli, Omar

    2015-10-30

    The clinical significance of high levels of homocysteine in autism spectrum disorder (ASD) is unknown. An experimental study was conducted in order to evaluate the concentration of homocysteine in children with ASD and typically developing children and to analyse any relationships with the severity of core symptoms of ASD and other clinical features (drugs, co-morbidities, gender, age, diet). Core symptoms of autism were evaluated by DSM-IV criteria. Homocysteine, glutathione, methionine, 3-nitrotyrosine were measured in urine. The increase in homocysteine concentration was significantly and directly correlated with the severity of the deficit in communication skills, but was unrelated to deficit in socialisation or repetitive/restricted behaviour. Urinary homocysteine concentration may be a possible biomarker for communication deficits in ASD and a potential diagnostic tool useful to evaluate new treatment options since no treatment for core symptoms of ASD are available.

  11. A rapid-pressure correlation representation consistent with the Taylor-Proudman theorem materially-frame-indifferent in the 2D limit

    NASA Technical Reports Server (NTRS)

    Ristorcelli, J. R.; Lumley, J. L.; Abid, R.

    1994-01-01

    A nonlinear representation for the rapid-pressure correlation appearing in the Reynolds stress equations, consistent with the Taylor-Proudman theorem, is presented. The representation insures that the modeled second-order equations are frame-invariant with respect to rotation when the flow is two-dimensional in planes perpendicular to the axis of rotation. The representation satisfies realizability in a new way: a special ansatz is used to obtain analytically, the values of coefficients valid away from the realizability limit: the model coefficients are functions of the state of the turbulence that are valid for all states of the mechanical turbulence attaining their constant limiting values only when the limit state is achieved. Utilization of all the mathematical constraints are not enough to specify all the coefficients in the model. The unspecified coefficients appear as free parameters which are used to insure that the representation is asymptotically consistent with the known equilibrium states of a homogeneous sheared turbulence. This is done by insuring that the modeled evolution equations have the same fixed points as those obtained from computer and laboratory experiments for the homogeneous shear. Results of computations of the homogeneous shear, with and without rotation, and with stabilizing and destabilizing curvature, are shown. Results are consistently better, in a wide class of flows which the model not been calibrated, than those obtained with other nonlinear models.

  12. Determination of chemical changes in Isatis indigotica seeds carried after Chinese first spaceship with FTIR and 2D-IR correlation spectroscopy.

    PubMed

    Chen, Xiangdong; Keong, Choong Yew; Mei, Xiling; Lan, Jin

    2014-04-24

    Spaceflight represents a complex environmental condition. Space mutagenesis breeding has achieved and marked certain results over the years. This method was employed in our previous studies in order to obtain improved germplasm of Isatis indigotica. This study is to determine the chemical changes in I. indigotica seeds carried after Chinese first spaceship (Shenzhou I). Fourier transform infrared (FTIR), second derivative and two-dimensional infrared (2DIR) correlation spectroscopy were used in analysis. Not much differences between the two spectra were found except the peaks in the range of 1500-1200 cm(-)(1) which was about 7 cm(-)(1) different and indicated the absorption could be initialed from different bonds. SP4 showed different derivative compared with C4 in the second derivative spectra of 1200-800 cm(-)(1). The stronger signal of 2DIR in SP4 indicated the protein content of the seed was changed after spaceflight. It is concluded that spaceflight provided an extreme condition that caused changes of chemical properties in I. indigotica.

  13. Assessing 2D electrophoretic mobility spectroscopy (2D MOSY) for analytical applications.

    PubMed

    Fang, Yuan; Yushmanov, Pavel V; Furó, István

    2016-12-08

    Electrophoretic displacement of charged entity phase modulates the spectrum acquired in electrophoretic NMR experiments, and this modulation can be presented via 2D FT as 2D mobility spectroscopy (MOSY) spectra. We compare in various mixed solutions the chemical selectivity provided by 2D MOSY spectra with that provided by 2D diffusion-ordered spectroscopy (DOSY) spectra and demonstrate, under the conditions explored, a superior performance of the former method. 2D MOSY compares also favourably with closely related LC-NMR methods. The shape of 2D MOSY spectra in complex mixtures is strongly modulated by the pH of the sample, a feature that has potential for areas such as in drug discovery and metabolomics. Copyright © 2016 The Authors. Magnetic Resonance in Chemistry published by John Wiley & Sons Ltd. StartCopTextCopyright © 2016 The Authors. Magnetic Resonance in Chemistry published by John Wiley & Sons Ltd.

  14. Characterization of transform faults within the South Georgia Rift using 2-D seismic line SCO2-3 correlated with well data

    NASA Astrophysics Data System (ADS)

    Mccormack, K. A.; Heffner, D. M.; Knapp, J. H.

    2012-12-01

    The South Georgia Rift Basin (SGR) has long been thought to be relatively simple on terms of its geology: with coastal plain sediments that vary gradually in thickness overlying a relatively uniform basalt province known as the "J-horizon". However recent re-examination of well data collected throughout the SGR suggests there are a number of generally NW-SE striking transform faults within the area due to the fact that the depth of the coastal plain sediments vary drastically over short lateral distances. (Hefner, D.M., 2011) To better understand these anomalies, we interpret the seismic line SCO2-3 collected in 2010 that looks to cross a transform fault at a high angle. By doing so and correlating it with available well and gravity data we will contribute to a better understanding of the South Georgia Rift (SGR) by determining the location and orientation of this transform fault. These possible faults are currently only constrained by well data and thus their exact strike, location and extent remain poorly understood. The characterization of the transform faults within this area is important due to the possibility of CO2 sequestration in parts of the SGR. It has also been suggested that the transform faults cutting through the SGR may line up with, and have originally been connected to, the transform faults that are found along the Mid Atlantic Ridge today. A better understanding of the extent, orientation and movement of these faults through seismic studies is essential to understanding the overall geology of the Sough Georgia Rift Basin.

  15. Exact e-e (exchange) correlations of 2-D quantum dots in magnetic field: Size extensive N = 3 , 4 , … , ‧ n ‧ -electron systems via multi-pole expansion

    NASA Astrophysics Data System (ADS)

    Aggarwal, Priyanka; Sharma, Shivalika; Singh, Sunny; Kaur, Harsimran; Hazra, Ram Kuntal

    2017-04-01

    Inclusion of coulomb interaction emerges with the complexity of either convergence of integrals or separation of variables of Schrödinger equations. For an N-electron system, interaction terms grow by N(N-1)/2 factors. Therefore, 2-e system stands as fundamental basic unit for generalized N-e systems. For the first time, we have evaluated e-e correlations in very simple and absolutely terminating finite summed hypergeometric series for 2-D double carrier parabolic quantum dot in both zero and arbitrary non-zero magnetic field (symmetric gauge) and have appraised these integrals in variational methods. The competitive role among confinement strength, magnetic field, mass of the carrier and dielectric constant of the medium on energy level diagram, level-spacing statistics, heat capacities (Cv at 1 K) and magnetization (T ∼ (0-1)K) is studied on systems spanning over wide range of materials (GaAs,Ge,CdS,SiO2 and He, etc). We have also constructed an exact theory for generalized correlated N-e 2-D quantum dots via multi-pole expansion but for the sake of compactness of the article we refrain from data.

  16. Correlations of CYP2C9∗3/CYP2D6∗10/CYP3A5∗3 gene polymorphisms with efficacy of etanercept treatment for patients with ankylosing spondylitis

    PubMed Central

    Chen, Yuan-Yuan

    2017-01-01

    Abstract Background: The tumor necrosis factor alpha (TNF-α) inhibitor etanercept has been proven to be effective in the treatment of ankylosing spondylitis (AS), while genetic polymorphism may affect drug metabolism or drug receptor, resulting in interindividual variability in drug disposition and efficacy. The purpose of this study is to investigate the correlations between CYP2C9∗3/CYP2D6∗10/CYP3A5∗3 gene polymorphisms and the efficacy of etanercept treatment for patients with AS. Methods: From March 2012 to June 2015, 312 AS patients (174 males and 138 females, mean age: 35.2 ± 5.83 years) from 18 to 56 years old were enrolled in this study. Polymerase chain reaction-restriction fragment length polymorphism was applied to detect the allele and genotype frequencies of CYP2C9∗3, CYP2D6∗10, and CYP3A5∗3 gene polymorphisms. The joint swelling score, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) level of AS patients were compared before and after 24-week etanercept treatment. Assessment in Ankylosing Spondylitis (ASAS) and bath ankylosing spondylitis disease activity index (BASDAI) scores were recorded to assess the efficacy of etanercept treatment. Results: The AS patients with wild-type ∗1/∗1 and heterozygous ∗1/∗3 genotypes of CYP2C9∗3 polymorphism accounted for 93.59% and 6.41%, respectively, without ∗3/∗3 genotype. The AS patients with wild-type CC, heterozygous CT, and mutation homozygous TT genotypes of CYP2D6∗10 polymorphism accounted for 19.23%, 39.10%, and 41.67%, respectively. The AS patients with wild-type ∗1/∗1, heterozygous ∗1/∗3, and mutation homozygous ∗3/∗3 genotypes of CYP3A5∗3 polymorphism accounted for 7.69%, 36.22%, and 56.09%, respectively. After 24-week treatment, AS patients with wild-type ∗1/∗1 genotype of CYP2C9∗3, CC genotype of CYP2D6∗10, and ∗3/∗3 genotype of CYP3A5∗3 polymorphisms had lower joint swelling score, ESR, and CRP level. The joint swelling

  17. Vertical 2D Heterostructures

    NASA Astrophysics Data System (ADS)

    Lotsch, Bettina V.

    2015-07-01

    Graphene's legacy has become an integral part of today's condensed matter science and has equipped a whole generation of scientists with an armory of concepts and techniques that open up new perspectives for the postgraphene area. In particular, the judicious combination of 2D building blocks into vertical heterostructures has recently been identified as a promising route to rationally engineer complex multilayer systems and artificial solids with intriguing properties. The present review highlights recent developments in the rapidly emerging field of 2D nanoarchitectonics from a materials chemistry perspective, with a focus on the types of heterostructures available, their assembly strategies, and their emerging properties. This overview is intended to bridge the gap between two major—yet largely disjunct—developments in 2D heterostructures, which are firmly rooted in solid-state chemistry or physics. Although the underlying types of heterostructures differ with respect to their dimensions, layer alignment, and interfacial quality, there is common ground, and future synergies between the various assembly strategies are to be expected.

  18. Working memory and visuospatial deficits correlate with oculomotor control in children with fetal alcohol spectrum disorder.

    PubMed

    Paolozza, Angelina; Rasmussen, Carmen; Pei, Jacqueline; Hanlon-Dearman, Ana; Nikkel, Sarah M; Andrew, Gail; McFarlane, Audrey; Samdup, Dawa; Reynolds, James N

    2014-04-15

    Previous studies have demonstrated that children with Fetal Alcohol Spectrum Disorder (FASD) exhibit deficits in measures of eye movement control that probe aspects of visuospatial processing and working memory. The goal of the present study was to examine, in a large cohort of children with FASD, prenatal alcohol exposure (PAE) but not FASD, and typically developing control children, the relationship between performance in eye movement tasks and standardized psychometric tests that assess visuospatial processing and working memory. Participants for this dataset were drawn from a large, multi-site investigation, and included children and adolescents aged 5-17 years diagnosed with an FASD (n=71), those with PAE but no clinical FASD diagnosis (n=20), and typically developing controls (n=111). Participants completed a neurobehavioral test battery and a series of saccadic eye movement tasks. The FASD group performed worse than controls on the psychometric and eye movement measures of working memory and visuospatial skills. Within the FASD group, digit recall, block recall, and animal sorting were negatively correlated with sequence errors on the memory-guided task, and arrows was negatively correlated with prosaccade endpoint error. There were no significant correlations in the control group. These data suggest that psychometric tests and eye movement control tasks may assess similar domains of cognitive function, and these assessment tools may be measuring overlapping brain regions damaged due to prenatal alcohol exposure. The results of this study demonstrate that eye movement control tasks directly relate to outcome measures obtained with psychometric tests and are able to assess multiple domains of cognition simultaneously, thereby allowing for an efficient and accurate assessment.

  19. 2D semiconductor optoelectronics

    NASA Astrophysics Data System (ADS)

    Novoselov, Kostya

    The advent of graphene and related 2D materials has recently led to a new technology: heterostructures based on these atomically thin crystals. The paradigm proved itself extremely versatile and led to rapid demonstration of tunnelling diodes with negative differential resistance, tunnelling transistors, photovoltaic devices, etc. By taking the complexity and functionality of such van der Waals heterostructures to the next level we introduce quantum wells engineered with one atomic plane precision. Light emission from such quantum wells, quantum dots and polaritonic effects will be discussed.

  20. Identification of Serine Conformers by Matrix-Isolation IR Spectroscopy Aided by Near-Infrared Laser-Induced Conformational Change, 2D Correlation Analysis, and Quantum Mechanical Anharmonic Computations.

    PubMed

    Najbauer, Eszter E; Bazsó, Gábor; Apóstolo, Rui; Fausto, Rui; Biczysko, Malgorzata; Barone, Vincenzo; Tarczay, György

    2015-08-20

    The conformers of α-serine were investigated by matrix-isolation IR spectroscopy combined with NIR laser irradiation. This method, aided by 2D correlation analysis, enabled unambiguously grouping the spectral lines to individual conformers. On the basis of comparison of at least nine experimentally observed vibrational transitions of each conformer with empirically scaled (SQM) and anharmonic (GVPT2) computed IR spectra, six conformers were identified. In addition, the presence of at least one more conformer in Ar matrix was proved, and a short-lived conformer with a half-life of (3.7 ± 0.5) × 10(3) s in N2 matrix was generated by NIR irradiation. The analysis of the NIR laser-induced conversions revealed that the excitation of the stretching overtone of both the side chain and the carboxylic OH groups can effectively promote conformational changes, but remarkably different paths were observed for the two kinds of excitations.

  1. Correlation between Nutrition and Symptoms: Nutritional Survey of Children with Autism Spectrum Disorder in Chongqing, China

    PubMed Central

    Liu, Xiao; Liu, Juan; Xiong, Xueqin; Yang, Ting; Hou, Nali; Liang, Xiaohua; Chen, Jie; Cheng, Qian; Li, Tingyu

    2016-01-01

    Restricted diets and inadequate nutrient intake of children with autism spectrum disorder (ASD) have been reported. This study examined the nutritional statuses of children with ASD and the relationships between their behaviors and nutritional intake. A total of 154 children with ASD (age = 5.21 ± 1.83 years) and 73 typically-developing (TD) children (age = 4.83 ± 0.84 years) from Chongqing, China, were enrolled. The severity of ASD was evaluated using the Childhood Autism Rating Scale (CARS). The serum ferritin, folate, vitamin B12, 25(OH) vitamin D, and vitamin A concentrations in the children with ASD were determined. All participants underwent anthropometric examinations, dietary assessments, and questionnaire assessments about their feeding behaviors, and gastrointestinal symptoms. The ZHA, ZWA, and ZBMIA were found to be significantly lower in the children with ASD compared with those without ASD. In addition, the percentages of children exhibiting severe picky eating and severe resistance to new foods, as well as those with a reported general impression of severe eating problems and constipation, were higher among the children with ASD. These children consumed significantly fewer macronutrients compared with the children without ASD. In addition, the children with ASD had the highest rate of vitamin A deficiency, followed by iron deficiency. After adjusting for sex, the vitamin A concentration was found to be negatively correlated with the CARS score (rs = −0.222, p = 0.021). No correlation between the ferritin, folate, vitamin D, or vitamin B12 concentration and the CARS score was found. These results suggest that reduced macronutrient intakes, severe feeding behavior issues, constipation, and vitamin A deficiency are quite common among children with ASD. Further, a low serum vitamin A level may be a risk factor for symptoms of ASD. However, the underlying mechanism should be further studied. PMID:27187463

  2. Correlation between Nutrition and Symptoms: Nutritional Survey of Children with Autism Spectrum Disorder in Chongqing, China.

    PubMed

    Liu, Xiao; Liu, Juan; Xiong, Xueqin; Yang, Ting; Hou, Nali; Liang, Xiaohua; Chen, Jie; Cheng, Qian; Li, Tingyu

    2016-05-14

    Restricted diets and inadequate nutrient intake of children with autism spectrum disorder (ASD) have been reported. This study examined the nutritional statuses of children with ASD and the relationships between their behaviors and nutritional intake. A total of 154 children with ASD (age = 5.21 ± 1.83 years) and 73 typically-developing (TD) children (age = 4.83 ± 0.84 years) from Chongqing, China, were enrolled. The severity of ASD was evaluated using the Childhood Autism Rating Scale (CARS). The serum ferritin, folate, vitamin B12, 25(OH) vitamin D, and vitamin A concentrations in the children with ASD were determined. All participants underwent anthropometric examinations, dietary assessments, and questionnaire assessments about their feeding behaviors, and gastrointestinal symptoms. The ZHA, ZWA, and ZBMIA were found to be significantly lower in the children with ASD compared with those without ASD. In addition, the percentages of children exhibiting severe picky eating and severe resistance to new foods, as well as those with a reported general impression of severe eating problems and constipation, were higher among the children with ASD. These children consumed significantly fewer macronutrients compared with the children without ASD. In addition, the children with ASD had the highest rate of vitamin A deficiency, followed by iron deficiency. After adjusting for sex, the vitamin A concentration was found to be negatively correlated with the CARS score (rs = -0.222, p = 0.021). No correlation between the ferritin, folate, vitamin D, or vitamin B12 concentration and the CARS score was found. These results suggest that reduced macronutrient intakes, severe feeding behavior issues, constipation, and vitamin A deficiency are quite common among children with ASD. Further, a low serum vitamin A level may be a risk factor for symptoms of ASD. However, the underlying mechanism should be further studied.

  3. Hoarding in Youth with Autism Spectrum Disorders and Anxiety: Incidence, Clinical Correlates, and Behavioral Treatment Response.

    PubMed

    Storch, Eric A; Nadeau, Joshua M; Johnco, Carly; Timpano, Kiara; McBride, Nicole; Jane Mutch, P; Lewin, Adam B; Murphy, Tanya K

    2016-05-01

    This study examined the nature and correlates of hoarding among youth with autism spectrum disorders (ASD). Forty children with ASD and a comorbid anxiety disorder were administered a battery of clinician-administered measures assessing presence of psychiatric disorders and anxiety severity. Parents completed questionnaires related to child hoarding behaviors, social responsiveness, internalizing and externalizing behaviors, and functional impairment. We examined the impact of hoarding behaviors on treatment response in a subsample of twenty-six youth who completed a course of personalized cognitive-behavioral therapy targeting anxiety symptoms. Hoarding symptoms were common and occurred in a clinically significant manner in approximately 25 % of cases. Overall hoarding severity was associated with increased internalizing and anxiety/depressive symptoms, externalizing behavior, and attention problems. Discarding items was associated with internalizing and anxious/depressive symptoms, but acquisition was not. Hoarding decreased following cognitive-behavioral therapy but did not differ between treatment responders and non-responders. These data are among the first to examine hoarding among youth with ASD; implications of study findings and future directions are highlighted.

  4. Clinical Correlates of Suicide in Suicidal Patients with Schizophrenia Spectrum Disorders and Affective Disorders

    PubMed Central

    Singh, Hemendra; Chandra, Prabha S.; Reddi, V. Senthil Kumar

    2016-01-01

    Background: The most common psychiatric illnesses in the background of suicide are schizophrenia spectrum disorders (SSD) and affective disorders (AD). While depression and hopelessness are important factors for suicide in psychiatric patients, the role of psychotic symptoms is unclear. We examine the comparative differences in the clinical correlates of suicide in SSD and AD patients with suicidal risk. Materials and Methods: One hundred and twenty suicidal psychiatric patients (aged between 17–60 years) were evaluated for depression severity, hopelessness, past attempts, and reasons for wanting to commit suicide at the emergency psychiatry centre. Of these 29% had SSD, 65% AD, and 6% other disorders. Results: Lifetime history of suicide attempts and suicide attempts in previous month were higher in SSD patients. Mean Beck Depression scores, Hopelessness, and Suicide Intention scores were significantly lower in patients with SSD as compared to AD (P ≤ 0.05). More than 60% patients with SSD attributed psychotic symptoms as a reason for wanting to commit suicide, while more than 50% patients with AD attributed it to family and personal stressors (P ≤ 0.001). Conclusions: Factors associated with suicidal ideations were significantly different between SSD and AD patients. Hence, suicide prevention strategies should be based on the specific risk factors for each group, SSD and AD. PMID:28031586

  5. Low-temperature spectrum of correlation lengths of the XXZ chain in the antiferromagnetic massive regime

    NASA Astrophysics Data System (ADS)

    Dugave, Maxime; Göhmann, Frank; Kozlowski, Karol K.; Suzuki, Junji

    2015-08-01

    We consider the spectrum of correlation lengths of the spin-\\displaystyle \\frac{1}{2} XXZ chain in the antiferromagnetic massive regime. These are given as ratios of eigenvalues of the quantum transfer matrix of the model. The eigenvalues are determined by integrals over certain auxiliary functions and by their zeros. The auxiliary functions satisfy nonlinear integral equations. We analyse these nonlinear integral equations in the low-temperature limit. In this limit we can determine the auxiliary functions and the expressions for the eigenvalues as functions of a finite number of parameters which satisfy finite sets of algebraic equations, the so-called higher-level Bethe ansatz equations. The behaviour of these equations, if we send the temperature T to zero, is different for zero and non-zero magnetic field h. If h is zero the situation is much like in the case of the usual transfer matrix. Non-trivial higher-level Bethe ansatz equations remain which determine certain complex excitation parameters as functions of hole parameters which are free on a line segment in the complex plane. If h is non-zero, on the other hand, a remarkable restructuring occurs, and all parameters which enter the description of the quantum transfer matrix eigenvalues can be interpreted entirely in terms of particles and holes which are freely located on two curves when T goes to zero. Dedicated to Professor Baxter on the occasion of his 75th birthday.

  6. Overweight and Obesity: Prevalence and Correlates in a Large Clinical Sample of Children with Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Zuckerman, Katharine E.; Hill, Alison P.; Guion, Kimberly; Voltolina, Lisa; Fombonne, Eric

    2014-01-01

    Autism Spectrum Disorders (ASDs) and childhood obesity (OBY) are rising public health concerns. This study aimed to evaluate the prevalence of overweight (OWT) and OBY in a sample of 376 Oregon children with ASD, and to assess correlates of OWT and OBY in this sample. We used descriptive statistics, bivariate, and focused multivariate analyses to…

  7. Eye-Tracking, Autonomic, and Electrophysiological Correlates of Emotional Face Processing in Adolescents with Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Wagner, Jennifer B.; Hirsch, Suzanna B.; Vogel-Farley, Vanessa K.; Redcay, Elizabeth; Nelson, Charles A.

    2013-01-01

    Individuals with autism spectrum disorder (ASD) often have difficulty with social-emotional cues. This study examined the neural, behavioral, and autonomic correlates of emotional face processing in adolescents with ASD and typical development (TD) using eye-tracking and event-related potentials (ERPs) across two different paradigms. Scanning of…

  8. Recovering the Fermi surface with 2D-ACAR spectroscopy in samples with defects

    NASA Astrophysics Data System (ADS)

    Dugdale, S. B.; Laverock, J.

    2014-04-01

    When two-dimensional angular correlation of positron annihilation radiation (2D-ACAR) experiments are performed in metals containing defects, conventional analysis in which the measured momentum distribution is folded back into the first Brillouin zone is rendered ineffective due to the contribution from positrons annihilating from the defect. However, by working with the radial anisotropy of the spectrum, it is shown that an image of the Fermi surface can be recovered since the defect contribution is essentially isotropic.

  9. Divergent Thinking Abilities across the Schizophrenic Spectrum and Other Psychological Correlates

    ERIC Educational Resources Information Center

    Rodrigue, Amanda L.; Perkins, David R.

    2012-01-01

    The literature on the connection between psychopathology and creativity is vast and recent research has focused on the relationship between the schizophrenic spectrum and creativity. The schizophrenic spectrum includes genetically related disorders that share certain symptom features. It has been suggested that schizotypal personality disorder, a…

  10. Neural Correlates of Own Name and Own Face Detection in Autism Spectrum Disorder

    PubMed Central

    Cygan, Hanna B.; Tacikowski, Pawel; Ostaszewski, Pawel; Chojnicka, Izabela; Nowicka, Anna

    2014-01-01

    Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental condition clinically characterized by social interaction and communication difficulties. To date, the majority of research efforts have focused on brain mechanisms underlying the deficits in interpersonal social cognition associated with ASD. Recent empirical and theoretical work has begun to reveal evidence for a reduced or even absent self-preference effect in patients with ASD. One may hypothesize that this is related to the impaired attentional processing of self-referential stimuli. The aim of our study was to test this hypothesis. We investigated the neural correlates of face and name detection in ASD. Four categories of face/name stimuli were used: own, close-other, famous, and unknown. Event-related potentials were recorded from 62 electrodes in 23 subjects with ASD and 23 matched control subjects. P100, N170, and P300 components were analyzed. The control group clearly showed a significant self-preference effect: higher P300 amplitude to the presentation of own face and own name than to the close-other, famous, and unknown categories, indicating preferential attentional engagement in processing of self-related information. In contrast, detection of both own and close-other's face and name in the ASD group was associated with enhanced P300, suggesting similar attention allocation for self and close-other related information. These findings suggest that attention allocation in the ASD group is modulated by the personal significance factor, and that the self-preference effect is absent if self is compared to close-other. These effects are similar for physical and non-physical aspects of the autistic self. In addition, lateralization of face and name processing is attenuated in ASD, suggesting atypical brain organization. PMID:24465847

  11. Theoretical evaluation of Brillouin dynamic grating length localized by optical correlation domain technique through reflection spectrum simulation

    NASA Astrophysics Data System (ADS)

    Kendy Yamashita, Rodrigo; Kishi, Masato; Hotate, Kazuo

    2017-04-01

    We derive formulae based on Fourier transformation to calculate the reflection spectrum of a Brillouin dynamic grating (BDG), which is localized along an optical fiber by an optical correlation domain technique. First, we calculate the typical reflection spectra of the BDG localized by the technique and confirm the validity of the formulae by showing coincidence with previous theoretical or experimental works. Next, we evaluate theoretically the spatial resolution in the BDG distributed measurement by the technique, through simulations considering different strained fiber lengths. It is confirmed theoretically, for the first time, that the resolution in the BDG measurement is worse than that for the Brillouin gain spectrum.

  12. Clinical correlates of plasma brain-derived neurotrophic factor in post-traumatic stress disorder spectrum after a natural disaster.

    PubMed

    Stratta, Paolo; Sanità, Patrizia; Bonanni, Roberto L; de Cataldo, Stefano; Angelucci, Adriano; Rossi, Rodolfo; Origlia, Nicola; Domenici, Luciano; Carmassi, Claudia; Piccinni, Armando; Dell'Osso, Liliana; Rossi, Alessandro

    2016-10-30

    Clinical correlates of plasma Brain-Derived Neurotrophic Factor (BDNF) have been investigated in a clinical population with Post Traumatic Stress Disorder (PTSD) symptoms and healthy control subjects who survived to the L'Aquila 2009 earthquake. Twenty-six outpatients and 14 control subjects were recruited. Assessments included: Structured Clinical Interview for DSM-IV Axis-I disorders Patient Version, Trauma and Loss Spectrum-Self Report (TALS-SR) for post-traumatic spectrum symptoms. Thirteen patients were diagnosed as Full PTSD and 13 as Partial PTSD. The subjects with full-blown PTSD showed lower BDNF level than subjects with partial PTSD and controls. Different relationship patterns of BDNF with post-traumatic stress spectrum symptoms have been reported in the three samples. Our findings add more insight on the mechanisms regulating BDNF levels in response to stress and further proofs of the utility of the distinction of PTSD into full and partial categories.

  13. Two-time correlation of heat release rate and spectrum of combustion noise from turbulent premixed flames

    NASA Astrophysics Data System (ADS)

    Liu, Yu

    2015-09-01

    The spectral characteristics of combustion noise are dictated by the temporal correlation of the overall change of heat release rate fluctuations which has not received sufficient attention in prior studies. In this work, the two-time correlation of the volumetric heat release rate fluctuations within the flame brush and its role in modeling combustion noise spectrum are investigated by analyzing direct numerical simulation (DNS) data of turbulent premixed V-flames. This two-time correlation can be well represented by Gaussian-type functions and it captures the slow global variation of the fluctuating heat release rate and hence the low-frequency noise sources of unsteady combustion. The resulting correlation model is applied to predict the far-field noise spectrum from test open flames, and different reference time scales are used to scale this correlation from the DNS data to the test flames. The comparison between predictions and measurements indicates that the correlation models of all reference time scales are capable of reproducing the essential spectral shape including the low- and high-frequency dependencies. Reasonable agreement in the peak frequency, peak sound pressure level, and the Strouhal number scaling of peak frequency is also achieved for two turbulent time scales. A promising convective time scale shows great potential for characterizing the spectral features, yet its predictive capabilities are to be further verified through a longer DNS signal of a bounded flame configuration.

  14. Fluoxetine response in children with autistic spectrum disorders: correlation with familial major affective disorder and intellectual achievement.

    PubMed

    DeLong, G Robert; Ritch, Chad R; Burch, Sherri

    2002-10-01

    One hundred and twenty-nine children, 2 to 8 years old, with idiopathic autistic spectrum disorder diagnosed by standard instruments (Childhood Austim Ratings Scale and Autism Diagnostic Observation Schedule) were treated with fluoxetine (0.15 to 0.5mg/kg) for 5 to 76 months (mean 32 to 36 months), with discontinuation trials. Response criteria are described. Family histories were obtained using the family history method in repeated interviews. Fluoxetine response, family history of major affective disorder, and unusual intellectual achievement, pretreatment language, and hyperlexia were used to define a coherent subgroup of autistic spectrum disorder. Statistical analyses were post hoc. Of the children, 22 (17%) had an excellent response, 67 (52%) good, and 40 (31%) fair/poor. Treatment age did not correlate with response. Fluoxetine response correlated robustly with familial major affective disorder and unusual intellectual achievement, and with hyperlexia in the child. Family history of bipolar disorder and of unusual intellectual achievement correlated strongly. Five children developed bipolar disorder during follow-up. Fluoxetine response, family history of major affective disorder (especially bipolar), unusual achievement, and hyperlexia in the children appear to define a homogeneous autistic subgroup. Bipolar disorder, unusual intellectual achievement, and autistic spectrum disorders cluster strongly in families and may share genetic determinants.

  15. 2D to 3D transition of polymeric carbon nitride nanosheets

    SciTech Connect

    Chamorro-Posada, Pedro; Vázquez-Cabo, José; Martín-Ramos, Pablo; Martín-Gil, Jesús; Navas-Gracia, Luis M.; Dante, Roberto C.

    2014-11-15

    The transition from a prevalent turbostratic arrangement with low planar interactions (2D) to an array of polymeric carbon nitride nanosheets with stronger interplanar interactions (3D), occurring for samples treated above 650 °C, was detected by terahertz-time domain spectroscopy (THz-TDS). The simulated 3D material made of stacks of shifted quasi planar sheets composed of zigzagged polymer ribbons, delivered a XRD simulated pattern in relatively good agreement with the experimental one. The 2D to 3D transition was also supported by the simulation of THz-TDS spectra obtained from quantum chemistry calculations, in which the same broad bands around 2 THz and 1.5 THz were found for 2D and 3D arrays, respectively. This transition was also in accordance with the tightening of the interplanar distance probably due to an interplanar π bond contribution, as evidenced also by a broad absorption around 2.6 eV in the UV–vis spectrum, which appeared in the sample treated at 650 °C, and increased in the sample treated at 700 °C. The band gap was calculated for 1D and 2D cases. The value of 3.374 eV for the 2D case is, within the model accuracy and precision, in a relative good agreement with the value of 3.055 eV obtained from the experimental results. - Graphical abstract: 2D lattice mode vibrations and structural changes correlated with the so called “2D to 3D transition”. - Highlights: • A 2D to 3D transition has been detected for polymeric carbon nitride. • THz-TDS allowed us to discover and detect the 2D to 3D transition of polymeric carbon nitride. • We propose a structure for polymeric carbon nitride confirming it with THz-TDS.

  16. Developmental Correlates of Different Types of Motor Imitation in Young Children with Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    McDuffie, Andrea; Turner, Lauren; Stone, Wendy; Yoder, Paul; Wolery, Mark; Ulman, Teresa

    2007-01-01

    This study used a concurrent correlational design to examine associations between three types of motor imitation with objects and three proposed correlates in 32 two- and three-year-old children diagnosed with ASD. Attention-following and fine motor ability were significant, unique correlates of imitation in an observational learning context.…

  17. E-2D Advanced Hawkeye Aircraft (E-2D AHE)

    DTIC Science & Technology

    2015-12-01

    Selected Acquisition Report (SAR) RCS: DD-A&T(Q&A)823-364 E-2D Advanced Hawkeye Aircraft (E-2D AHE) As of FY 2017 President’s Budget Defense...Office Estimate RDT&E - Research, Development, Test, and Evaluation SAR - Selected Acquisition Report SCP - Service Cost Position TBD - To Be Determined

  18. Developmental Meta-Analysis of the Functional Neural Correlates of Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Dickstein, Daniel P.; Pescosolido, Matthew F.; Reidy, Brooke L.; Galvan, Thania; Kim, Kerri L.; Seymour, Karen E.; Laird, Angela R.; Di Martino, Adriana; Barrett, Rowland P.

    2013-01-01

    Objective: There is a pressing need to elucidate the brain-behavior interactions underlying autism spectrum disorders (ASD) given the marked rise in ASD diagnosis over the past decade. Functional magnetic resonance imaging (fMRI) has begun to address this need, but few fMRI studies have evaluated age-related changes in ASD. Therefore, we conducted…

  19. Neural Correlates of Verbal and Nonverbal Semantic Integration in Children with Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    McCleery, Joseph P.; Ceponiene, Rita; Burner, Karen M.; Townsend, Jeanne; Kinnear, Mikaela; Schreibman, Laura

    2010-01-01

    Background: Autism is a pervasive developmental disorder characterized by deficits in social-emotional, social-communicative, and language skills. Behavioral and neuroimaging studies have found that children with autism spectrum disorders (ASD) evidence abnormalities in semantic processing, with particular difficulties in verbal comprehension.…

  20. Prevalence and Correlates of Screen-Based Media Use among Youths with Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Mazurek, Micah O.; Shattuck, Paul T.; Wagner, Mary; Cooper, Benjamin P.

    2012-01-01

    Anecdotal reports indicate that individuals with autism spectrum disorders (ASD) are often preoccupied with television, computers, and video games (screen-based media). However, few studies have examined this issue. The current study examined screen-based media use among a large, nationally representative sample of youths participating in the…

  1. Sleep Disruption as a Correlate to Cognitive and Adaptive Behavior Problems in Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Taylor, Matthew A.; Schreck, Kimberly A.; Mulick, James A.

    2012-01-01

    Sleep problems associated with autism spectrum disorders (ASD) have been well documented, but less is known about the effects of sleep problems on day-time cognitive and adaptive performance in this population. Children diagnosed with autism or pervasive developmental disorder-not otherwise specified (PDD-NOS) (N = 335) from 1 to 10 years of age…

  2. Examination of Correlates of Different Imitative Functions in Young Children with Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Ingersoll, Brooke; Meyer, Katherine

    2011-01-01

    Children with autism spectrum disorders (ASD) have difficulties with social-communication skills, including imitation, language, joint attention, and play. This study investigated whether imitation performance in two different contexts (structured-elicited vs. social-interactive) was differentially related to attention-following, social…

  3. Correlates of Adaptive Functioning in Minimally Verbal Children with Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Frost, Kyle M.; Hong, Natalie; Lord, Catherine

    2017-01-01

    Individuals with autism spectrum disorder (ASD) tend to have significant delays in adaptive functioning. In this study, the relationship between adaptive behavior and ASD symptomatology was investigated in minimally verbal, school-aged children with ASD (n = 333). Both the social affect (SA) and restricted and repetitive behavior (RRB) domains…

  4. Neural Correlates of Facial Affect Processing in Children and Adolescents with Autism Spectrum Disorder.

    ERIC Educational Resources Information Center

    Wang, A. Ting; Dapretto, Mirella; Hariri, Ahmad R.; Sigman, Marian; Bookheimer, Susan Y.

    2004-01-01

    Objective: To examine the neural basis of impairments in interpreting facial emotions in children and adolescents with autism spectrum disorders (ASD). Method: Twelve children and adolescents with ASD and 12 typically developing (TD) controls matched faces by emotion and assigned a label to facial expressions while undergoing functional magnetic…

  5. Dual Cognitive and Biological Correlates of Anxiety in Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Hollocks, Matthew J.; Pickles, Andrew; Howlin, Patricia; Simonoff, Emily

    2016-01-01

    Young people with autism spectrum disorder (ASD) have a high prevalence (~40 %) of anxiety disorders compared to their non-ASD peers. It is unclear whether cognitive and biological processes associated with anxiety in ASD are analogous to anxiety in typically developing (TD) populations. In this study 55 boys with ASD (34 with a co-occurring…

  6. Examining the Clinical Correlates of Autism Spectrum Disorder in Youth by Ascertainment Source

    ERIC Educational Resources Information Center

    Joshi, Gagan; Faraone, Stephen V.; Wozniak, Janet; Petty, Carter; Fried, Ronna; Galdo, Maribel; Furtak, Stephannie L.; McDermott, Katie; Epstien, Cecily; Walker, Rosemary; Caron, Ashley; Feinberg, Leah; Biederman, Joseph

    2014-01-01

    To examine whether presentation of autism spectrum disorder (ASD) and associated patterns of psychiatric comorbidity and dysfunction vary by referral source. ASD youth referred to a specialized ambulatory program for ASD (N = 143) were compared to ASD youth referred to a general child psychiatry clinic (N = 217). More ASD clinic youth met criteria…

  7. Interuser Interference Analysis for Direct-Sequence Spread-Spectrum Systems Part I: Partial-Period Cross-Correlation

    NASA Technical Reports Server (NTRS)

    Ni, Jianjun (David)

    2012-01-01

    This presentation discusses an analysis approach to evaluate the interuser interference for Direct-Sequence Spread-Spectrum (DSSS) Systems for Space Network (SN) Users. Part I of this analysis shows that the correlation property of pseudo noise (PN) sequences is the critical factor which determines the interuser interference performance of the DSSS system. For non-standard DSSS systems in which PN sequence s period is much larger than one data symbol duration, it is the partial-period cross-correlation that determines the system performance. This study reveals through an example that a well-designed PN sequence set (e.g. Gold Sequence, in which the cross-correlation for a whole-period is well controlled) may have non-controlled partial-period cross-correlation which could cause severe interuser interference for a DSSS system. Since the analytical derivation of performance metric (bit error rate or signal-to-noise ratio) based on partial-period cross-correlation is prohibitive, the performance degradation due to partial-period cross-correlation will be evaluated using simulation in Part II of this analysis in the future.

  8. Fiber Bragg grating sensor fatigue crack real-time monitoring based on spectrum cross-correlation analysis

    NASA Astrophysics Data System (ADS)

    Bao, Pengyu; Yuan, Mei; Dong, Shaopeng; Song, Hao; Xue, Jingfeng

    2013-01-01

    As one of the most critical tasks in structural damage monitoring, real-time fatigue crack monitoring plays an important role in improving the durability of a structure. In this paper, an online fatigue crack detection method is investigated based on the fiber Bragg grating (FBG) crack monitoring test bed (FBG-CMTB). Aiming at detecting ultrasonic spread in the structure when the crack is growing, the spectrum cross-correlation analysis algorithm and the cross-correlation function sequence are two methods that we will investigate in detail. Considering the singularity characteristic of the crack detecting signals when crack initiates, the wavelet packet analysis method is applied for feature extraction and two damage factors, crack initiation factor (CIF) and crack propagation factor (CPF), are constructed for damage initiation and propagation degree identification. To analyze the efficiency of this method, this paper presents the comparison tests based on different sensors array, FBG and acoustic emission (AE). Experimental results shows a satisfactory performance of the proposed spectrum cross-correlation analysis (SCCA) and damage feature factors on the fatigue crack online monitoring.

  9. Deficient visuospatial working memory functions and neural correlates of the default-mode network in adolescents with autism spectrum disorder.

    PubMed

    Chien, Hsiang-Yun; Gau, Susan Shur-Fen; Isaac Tseng, Wen-Yih

    2016-10-01

    In addition to the essential features of autism spectrum disorder (ASD), namely social communication deficits and repetitive behaviors, individuals with ASD may suffer from working memory deficits and an altered default-mode network (DMN). We hypothesized that an altered DMN is related to working memory deficits in those with ASD. A total of 37 adolescents with ASD and 36 age- and IQ-matched typically developing (TD) controls were analyzed. Visuospatial working memory performance was assessed using pattern recognition memory (PRM), spatial recognition memory (SRM), and paired-associates learning (PAL) tasks. The intrinsic functional connectivity (iFC) of the DMN was indexed by the temporal correlations between the resting-state functional magnetic resonance imaging signals of pairs of DMN regions, including those between the posterior cingulate cortex (PCC) and medial prefrontal cortex (mPFC) and between the PCC and parahippocampi (PHG). The corresponding structural connectivity of the DMN was indexed by the generalized fractional anisotropy (GFA) of the dorsal and ventral cingulum bundles on the basis of diffusion spectrum imaging data. The results showed that ASD adolescents exhibited delayed correct responses in PRM and SRM tasks and committed more errors in the PAL task than the TD controls did. The delayed responses during the PRM and SRM tasks were negatively correlated with bilateral PCC-mPFC iFCs, and PAL performance was negatively correlated with right PCC-PHG iFC in ASD adolescents. Furthermore, ASD adolescents showed significant lower GFA in the right cingulum bundles than the TD group did; the GFA value was negatively correlated with SRM performance in ASD. Our results provide empirical evidence for deficient visuospatial working memory and corresponding neural correlates within the DMN in adolescents with ASD. Autism Res 2016, 9: 1058-1072. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.

  10. 2-D or not 2-D, that is the question: A Northern California test

    SciTech Connect

    Mayeda, K; Malagnini, L; Phillips, W S; Walter, W R; Dreger, D

    2005-06-06

    Reliable estimates of the seismic source spectrum are necessary for accurate magnitude, yield, and energy estimation. In particular, how seismic radiated energy scales with increasing earthquake size has been the focus of recent debate within the community and has direct implications on earthquake source physics studies as well as hazard mitigation. The 1-D coda methodology of Mayeda et al. has provided the lowest variance estimate of the source spectrum when compared against traditional approaches that use direct S-waves, thus making it ideal for networks that have sparse station distribution. The 1-D coda methodology has been mostly confined to regions of approximately uniform complexity. For larger, more geophysically complicated regions, 2-D path corrections may be required. The complicated tectonics of the northern California region coupled with high quality broadband seismic data provides for an ideal ''apples-to-apples'' test of 1-D and 2-D path assumptions on direct waves and their coda. Using the same station and event distribution, we compared 1-D and 2-D path corrections and observed the following results: (1) 1-D coda results reduced the amplitude variance relative to direct S-waves by roughly a factor of 8 (800%); (2) Applying a 2-D correction to the coda resulted in up to 40% variance reduction from the 1-D coda results; (3) 2-D direct S-wave results, though better than 1-D direct waves, were significantly worse than the 1-D coda. We found that coda-based moment-rate source spectra derived from the 2-D approach were essentially identical to those from the 1-D approach for frequencies less than {approx}0.7-Hz, however for the high frequencies (0.7{le} f {le} 8.0-Hz), the 2-D approach resulted in inter-station scatter that was generally 10-30% smaller. For complex regions where data are plentiful, a 2-D approach can significantly improve upon the simple 1-D assumption. In regions where only 1-D coda correction is available it is still preferable over 2

  11. Comparative effects of microcurrent stimulation on EEG spectrum and correlation dimension.

    PubMed

    Heffernan, M S

    1996-01-01

    Two mathematical derivatives of electroencephalogram (EEG), Fast Fourier Transform (FFT), and correlation dimension from chaos analysis were used to assess the objective effects of earlobe versus mid-trapezius microcurrent stimulation on brain EEG. These measures were considered to be clinically relevant since low points in the FFT have been associated with attention deficit disorder, and declining correlation dimension has been associated with onset of epilepsy. Thirty Subjects (30) were assigned randomly to one of three groups: earlobe, trapezius, and a double blind placebo control Earlobe stimulation (CES) was hypothesized to alter BEG since research suggests CES enters the brain directly, through a perineural or vascular path via the auditory meatus. Results showed that trapezius microcurrent therapy proved more effective in producing significant declines in FFT spectral smoothing, with an average standard deviation (SD) in the FFT of 1.1, as compared to the CES group showing an SD of 2.9. Correlation dimension in both trapezius and CES stimulation groups increased significantly (p < .001) as compared to placebo, with the correlation dimension measures for earlobe, trapezius, and placebo being 5.7, 5.6, and 3.7, respectively. The author discusses the significance of using body points for promoting clinically beneficial effects in brain electrophysiology as evidenced by improved FFT and correlation dimension.

  12. Energy Efficiency of D2D Multi-User Cooperation.

    PubMed

    Zhang, Zufan; Wang, Lu; Zhang, Jie

    2017-03-28

    The Device-to-Device (D2D) communication system is an important part of heterogeneous networks. It has great potential to improve spectrum efficiency, throughput and energy efficiency cooperation of multiple D2D users with the advantage of direct communication. When cooperating, D2D users expend extraordinary energy to relay data to other D2D users. Hence, the remaining energy of D2D users determines the life of the system. This paper proposes a cooperation scheme for multiple D2D users who reuse the orthogonal spectrum and are interested in the same data by aiming to solve the energy problem of D2D users. Considering both energy availability and the Signal to Noise Ratio (SNR) of each D2D user, the Kuhn-Munkres algorithm is introduced in the cooperation scheme to solve relay selection problems. Thus, the cooperation issue is transformed into a maximum weighted matching (MWM) problem. In order to enhance energy efficiency without the deterioration of Quality of Service (QoS), the link outage probability is derived according to the Shannon Equation by considering the data rate and delay. The simulation studies the relationships among the number of cooperative users, the length of shared data, the number of data packets and energy efficiency.

  13. DSM-5 PTSD and posttraumatic stress spectrum in Italian emergency personnel: correlations with work and social adjustment

    PubMed Central

    Carmassi, Claudia; Gesi, Camilla; Simoncini, Marly; Favilla, Luca; Massimetti, Gabriele; Olivieri, Maria Cristina; Conversano, Ciro; Santini, Massimo; Dell’Osso, Liliana

    2016-01-01

    The Diagnostic and Statistical Manual of Mental Disorders Fifth Edition (DSM-5) has recently recognized a particular risk for posttraumatic stress disorder (PTSD) among first responders (criterion A4), acknowledging emergency units as stressful places of employment. Little data is yet available on DSM-5 among emergency health operators. The aim of this study was to assess DSM-5 symptomatological PTSD and posttraumatic stress spectrum, as well as their impact on work and social functioning, in the emergency staff of a major university hospital in Italy. One hundred and ten subjects (doctors, nurses, and health-care assistants) were recruited at the Emergency Unit of the Azienda Ospedaliero-Universitaria Pisana (Italy) and assessed by the Trauma and Loss Spectrum-Self Report (TALS-SR) and Work and Social Adjustment Scale (WSAS). A 15.7% DSM-5 symptomatological PTSD prevalence rate was found. Nongraduated persons reported significantly higher TALS-SR Domain IV (reaction to loss or traumatic events) scores and a significantly higher proportion of individuals presenting at least one maladaptive behavior (TALS-SR Domain VII), with respect to graduate ones. Women reported significantly higher WSAS scores. Significant correlations emerged between PTSD symptoms and WSAS total scores among health-care assistants, nongraduates and women. Our results showed emergency workers to be at risk for posttraumatic stress spectrum and related work and social impairment, particularly among women and nongraduated subjects. PMID:26937192

  14. Correlates of Adaptive Functioning in Minimally Verbal Children With Autism Spectrum Disorder.

    PubMed

    Frost, Kyle M; Hong, Natalie; Lord, Catherine

    2017-01-01

    Individuals with autism spectrum disorder (ASD) tend to have significant delays in adaptive functioning. In this study, the relationship between adaptive behavior and ASD symptomatology was investigated in minimally verbal, school-aged children with ASD (n = 333). Both the social affect (SA) and restricted and repetitive behavior (RRB) domains from the Autism Diagnostic Observation Schedule (ADOS) were analyzed in relation to adaptive skills. ADOS SA scores contributed unique variance to scores in each Vineland domain, though cognitive ability and age accounted for considerably more variance across domains. Results indicate that there is a significant, but small, association between social affect deficits and adaptive skills, challenging clinicians, educators, and caregivers to target adaptive skills in addition to more specific features of ASD.

  15. Correlates of Attachment Perceptions in Parents of Children with Autism Spectrum Disorders.

    PubMed

    Goodman, Sabrina J; Glenwick, David S

    2012-10-01

    This study explored the relationship between parents' perceptions of their child's attachment to them and parents' own affective attachment to their child, as well the relationship of these constructs to parenting stress, parent-rated child functional impairment, and parenting sense of competence. Mothers (n = 76) and fathers (n = 30) of children ages 2-10 with autism spectrum disorders participated. Overall, parents' affective attachment to their child was more consistently related to other aspects of their parenting experiences than were their perceptions of their child's attachment to them. Also, perceptions of child-to-parent attachment were related to other aspects of parenting for fathers more than for mothers. Implications for parenting interventions and future research, such as longitudinal investigations, are discussed.

  16. Medical and Behavioral Correlates of Depression History in Children and Adolescents With Autism Spectrum Disorder

    PubMed Central

    Greenlee, Jessica L.; Mosley, Angela S.; Shui, Amy M.; Veenstra-VanderWeele, Jeremy

    2016-01-01

    BACKGROUND AND OBJECTIVES: Depression is commonly associated with autism spectrum disorder (ASD) across the life span. We sought to identify medical and behavioral problems associated with a history of a parent-reported diagnosis of depression in a large sample of school-aged children and adolescents with ASD. METHODS: A sample of 1272 participants (aged 6–17 years; mean [SD]: 9.56 [2.79] years) from the Autism Speaks Autism Treatment Network consortium were divided into “ever-depressed” (n = 89) and “nondepressed” (n = 1183) groups on the basis of caregiver endorsement of children’s current or previous diagnoses of depression. RESULTS: In total, 7.0% of children with ASD (4.8% of those aged 6–12 years and 20.2% of those aged 13–17 years) were reported to have a history of a depression diagnosis. Positive depression history was associated with greater chronological age, higher IQ, and Asperger disorder diagnosis. After controlling for age, IQ, and within-spectrum categorical diagnosis, the ever-depressed group exhibited significantly greater rates of seizure disorders (odds ratio = 2.64) and gastrointestinal problems (odds ratio = 2.59) and trend-level differences in aggression, somatic complaints, and social impairments. The groups did not differ in autism severity, repetitive behaviors, sleep problems, eating problems, self-injurious behavior, or current intervention use. CONCLUSIONS: Co-occurring depression is a particularly common problem in higher-functioning older children within the Autism Treatment Network. Our findings indicate that children with ASD and a history of a depression diagnosis are more likely to also have co-occurring medical problems, although the presence and direction of causality is unclear. PMID:26908466

  17. The Phenomenology and Clinical Correlates of Suicidal Thoughts and Behaviors in Youth with Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Storch, Eric A.; Sulkowski, Michael L.; Nadeau, Josh; Lewin, Adam B.; Arnold, Elysse B.; Mutch, P. Jane; Jones, Anna M.; Murphy, Tanya K.

    2013-01-01

    This study investigated the phenomenology and clinical correlates of suicidal thoughts and behaviors in youth with ASD (N = 102; range 7-16 years). The presence of suicidal thoughts and behavior was assessed through the Anxiety Disorders Interview Schedule-Child and Parent Versions. Children and parents completed measures of anxiety severity,…

  18. 2D ACAR momentum density study of the nature of the positron surface state on Al(100)

    SciTech Connect

    Berko, S.; Canter, K.F.; Lynn, K.G.; Mills, A.P.; Roellig, L.O.; West, R.N.

    1985-01-01

    The two-dimensional angular correlation of the 2..gamma.. annihilation radiation (2D ACAR) has been measured from an Al(100) surface bombarded by 200-eV positrons. After removing the contribution of fast para-positronium annihilation, the spectrum from positrons annihilating at the surface exhibits a nearly isotropic conical shape with a (7.1 +- 0.5) mrad FWHM. 5 refs., 6 figs.

  19. Effects of correlated noise on the full-spectrum combining and complex-symbol combining arraying techniques

    NASA Technical Reports Server (NTRS)

    Vazirani, P.

    1995-01-01

    The process of combining telemetry signals received at multiple antennas, commonly referred to as arraying, can be used to improve communication link performance in the Deep Space Network (DSN). By coherently adding telemetry from multiple receiving sites, arraying produces an enhancement in signal-to-noise ratio (SNR) over that achievable with any single antenna in the array. A number of different techniques for arraying have been proposed and their performances analyzed in past literature. These analyses have compared different arraying schemes under the assumption that the signals contain additive white Gaussian noise (AWGN) and that the noise observed at distinct antennas is independent. In situations where an unwanted background body is visible to multiple antennas in the array, however, the assumption of independent noises is no longer applicable. A planet with significant radiation emissions in the frequency band of interest can be one such source of correlated noise. For example, during much of Galileo's tour of Jupiter, the planet will contribute significantly to the total system noise at various ground stations. This article analyzes the effects of correlated noise on two arraying schemes currently being considered for DSN applications: full-spectrum combining (FSC) and complex-symbol combining (CSC). A framework is presented for characterizing the correlated noise based on physical parameters, and the impact of the noise correlation on the array performance is assessed for each scheme.

  20. Diagnostic performance of 3D TSE MRI versus 2D TSE MRI of the knee at 1.5 T, with prompt arthroscopic correlation, in the detection of meniscal and cruciate ligament tears*

    PubMed Central

    Chagas-Neto, Francisco Abaeté; Nogueira-Barbosa, Marcello Henrique; Lorenzato, Mário Müller; Salim, Rodrigo; Kfuri-Junior, Maurício; Crema, Michel Daoud

    2016-01-01

    Objective To compare the diagnostic performance of the three-dimensional turbo spin-echo (3D TSE) magnetic resonance imaging (MRI) technique with the performance of the standard two-dimensional turbo spin-echo (2D TSE) protocol at 1.5 T, in the detection of meniscal and ligament tears. Materials and Methods Thirty-eight patients were imaged twice, first with a standard multiplanar 2D TSE MR technique, and then with a 3D TSE technique, both in the same 1.5 T MRI scanner. The patients underwent knee arthroscopy within the first three days after the MRI. Using arthroscopy as the reference standard, we determined the diagnostic performance and agreement. Results For detecting anterior cruciate ligament tears, the 3D TSE and routine 2D TSE techniques showed similar values for sensitivity (93% and 93%, respectively) and specificity (80% and 85%, respectively). For detecting medial meniscal tears, the two techniques also had similar sensitivity (85% and 83%, respectively) and specificity (68% and 71%, respectively). In addition, for detecting lateral meniscal tears, the two techniques had similar sensitivity (58% and 54%, respectively) and specificity (82% and 92%, respectively). There was a substantial to almost perfect intraobserver and interobserver agreement when comparing the readings for both techniques. Conclusion The 3D TSE technique has a diagnostic performance similar to that of the routine 2D TSE protocol for detecting meniscal and anterior cruciate ligament tears at 1.5 T, with the advantage of faster acquisition. PMID:27141127

  1. Optoelectronics with 2D semiconductors

    NASA Astrophysics Data System (ADS)

    Mueller, Thomas

    2015-03-01

    Two-dimensional (2D) atomic crystals, such as graphene and layered transition-metal dichalcogenides, are currently receiving a lot of attention for applications in electronics and optoelectronics. In this talk, I will review our research activities on electrically driven light emission, photovoltaic energy conversion and photodetection in 2D semiconductors. In particular, WSe2 monolayer p-n junctions formed by electrostatic doping using a pair of split gate electrodes, type-II heterojunctions based on MoS2/WSe2 and MoS2/phosphorene van der Waals stacks, 2D multi-junction solar cells, and 3D/2D semiconductor interfaces will be presented. Upon optical illumination, conversion of light into electrical energy occurs in these devices. If an electrical current is driven, efficient electroluminescence is obtained. I will present measurements of the electrical characteristics, the optical properties, and the gate voltage dependence of the device response. In the second part of my talk, I will discuss photoconductivity studies of MoS2 field-effect transistors. We identify photovoltaic and photoconductive effects, which both show strong photoconductive gain. A model will be presented that reproduces our experimental findings, such as the dependence on optical power and gate voltage. We envision that the efficient photon conversion and light emission, combined with the advantages of 2D semiconductors, such as flexibility, high mechanical stability and low costs of production, could lead to new optoelectronic technologies.

  2. Correlation between Autism Treatment Evaluation Checklist (ATEC) and Childhood Autism Rating Scale (CARS) in the evaluation of autism spectrum disorder.

    PubMed

    Al Backer, Nouf Backer

    2016-01-01

    Identification of health issues in children with autism spectrum disorder (ASD) is paramount to provide appropriate care and interventions. The Autism Treatment Evaluation Checklist (ATEC) is the one of the few current measures that assesses ASD-associated health problems thus informing intervention decisions. However, little research has been conducted to compare ATEC with other more recognized measures such as the Childhood Autism Rating Scale (CARS). It is unclear whether these two scales can be used interchangeably or whether high scores on one scale are comparable to the other. The aim of the current study was to compare the correlation between ATEC and CARS in the evaluation of children with ASD. This prospective cross-sectional study was conducted at the Developmental and Behavioural Paediatrics Outpatient Clinic at King Saud University, King Khalid University hospital (KKUH) in Riyadh, Saudi Arabia. Forty children with a prior diagnosis of ASD seen during the period from October 2014 to August 2015 were included. Each child was assessed using ATEC and CARS independently during the same visit. The Spearman's rank correlation coefficient test was used. The overall mean CARS score was 34.125 ± 5.535 (range from 22 to 42) and the mean ATEC score was 40.95± 9.1934.1 (range from 24 to 72). The Spearman's rank correlation coefficient (rs) was 0.015, and p-value was 0.926 (> 0.05) meaning that there was no correlation between CARS and ATEC scales. No correlation between CARS and ATEC scale was found. ATEC should not be used instead of CARS to delineate co-morbid health issues. Future studies are needed to assess the validity of ATEC and its correlation with other well established scales.

  3. Clinical Correlates of Co-occurring Psychiatric and Autism Spectrum Disorder (ASD) Symptom-Induced Impairment in Children with ASD.

    PubMed

    Gadow, Kenneth D; Perlman, Greg; Ramdhany, Lianne; de Ruiter, Janneke

    2016-01-01

    Although psychiatric symptom severity and impairment are overlapping but nevertheless distinct illness parameters, little research has examined whether variables found to be associated with the severity are also correlated with symptom-induced impairment. Parents and teachers completed ratings of symptom-induced impairment for DSM-IV-referenced syndromes, and parents completed a background questionnaire for a consecutively referred sample of primarily male (81%) 6-to-12 year olds with autism spectrum disorder (ASD) (N = 221). Some clinical correlates (e.g., IQ < 70, maternal level of education, pregnancy complications, current use of psychotropic medication, season of birth) were associated with impairment for several disorders, whereas others were correlated with only a few syndromes (e.g., gender, co-morbid medical conditions) or were not related to impairment in any disorder (e.g., family psychopathology). There was little convergence in findings for parents' versus teachers' ratings. Some clinical correlates (e.g., season of birth, current psychotropic medication, maternal education) were unique predictors of three or more disorders. Pregnancy complications were uniquely associated with social anxiety and schizoid personality symptom-induced impairment. IQ was a unique predictor of schizophrenia, ASD, oppositional defiant disorder symptom-induced impairment. Children whose mothers had relatively fewer years of education had greater odds for symptom-induced impairment in social anxiety, depression, aggression, and mania and greater number of impairing conditions. Season of birth was the most robust correlate of symptom-induced impairment as rated by teachers but not by parents. Children born in fall evidenced higher rates of co-occurring psychiatric and ASD symptom-induced impairment and total number of impairing conditions. Many variables previously linked with symptom severity are also correlated with impairment.

  4. Anomalous echo: Exploring abnormal experience correlates of emotional motor resonance in Schizophrenia Spectrum.

    PubMed

    Sestito, Mariateresa; Raballo, Andrea; Umiltà, Maria Alessandra; Amore, Mario; Maggini, Carlo; Gallese, Vittorio

    2015-09-30

    Anomalous experiences such as Basic Symptoms (BS) are considered the first subjective manifestation of the neurobiological substrate of schizophrenia. The purpose of this study was to explore whether a low or high emotional motor resonance occurring in Schizophrenia Spectrum (SzSp) patients was related to patients׳ clinical features and to their anomalous subjective experiences as indexed by the Bonn Scale for the Assessment of Basic Symptoms (BSABS). To this aim, we employed a validated paradigm sensitive in evoking a congruent facial mimicry (measured by means of facial electromyographic activity, EMG) through multimodal positive and negative emotional stimuli presentation. Results showed that SzSp patients more resonating with negative emotional stimuli (i.e. Externalizers) had significantly higher scores in BSABS Cluster 3 (Vulnerability) and more psychotic episodes than Internalizers patients. On the other hand, SzSp patients more resonating with positive emotional stimuli (i.e. Externalizers) scored higher in BSABS Cluster 5 (Interpersonal irritation) than Internalizers. Drawing upon a phenomenological-based perspective, we attempted to shed new light on the abnormal experiences characterizing schizophrenia, explaining them in terms of a disruption of the normal self-perception conveyed by the basic, low-level emotional motor mechanisms.

  5. Correlates of Non-suicidal Self-Injury and Suicide Attempts in Bulimic Spectrum Disorders

    PubMed Central

    Gómez-Expósito, Alexandra; Wolz, Ines; Fagundo, Ana B.; Granero, Roser; Steward, Trevor; Jiménez-Murcia, Susana; Agüera, Zaida; Fernández-Aranda, Fernando

    2016-01-01

    Objective: The aim of this study was to examine the implication of personality, impulsivity, and emotion regulation difficulties in patients with a bulimic-spectrum disorder (BSD) and suicide attempts (SA), BSD patients with non-suicidal self-injury (NSSI), and BSD patients without these behaviors. Method: One hundred and twenty-two female adult BSD patients were assessed using self-report questionnaires. Patients were clustered post-hoc into three groups depending on whether they presented BSD without NSSI or SA (BSD), BSD with lifetime NSSI (BSD + NSSI) or BSD with lifetime SA (BSD + SA). Results: The BSD + NSSI and BSD + SA groups presented more emotion regulation difficulties, more eating and general psychopathology, and increased reward dependence in comparison with the BSD group. In addition, BSD + SA patients specifically showed problems with impulse control, while also presenting higher impulsivity than both the BSD and BSD + NSSI groups. No differences in impulsivity between the BSD and BSD + NSSI groups were found. Conclusions: The results show that BSD + NSSI and BSD + SA share a common profile characterized by difficulties in emotion regulation and low reward dependence, but differ in impulsivity and cooperativeness. This suggests that self-injury, in patients without a history of suicide attempts (i.e., BSD + NSSI), may have a regulatory role rather than being due to impulsivity. PMID:27597836

  6. Multimodal neuroimaging based classification of autism spectrum disorder using anatomical, neurochemical, and white matter correlates

    PubMed Central

    Libero, Lauren E.; DeRamus, Thomas P.; Lahti, Adrienne C.; Deshpande, Gopikrishna; Kana, Rajesh K.

    2016-01-01

    Neuroimaging techniques, such as fMRI, structural MRI, diffusion tensor imaging (DTI), and proton magnetic resonance spectroscopy (1H-MRS) have uncovered evidence for widespread functional and anatomical brain abnormalities in autism spectrum disorder (ASD) suggesting it to be a system-wide neural systems disorder. Nevertheless, most previous studies have focused on examining one index of neuropathology through a single neuroimaging modality, and seldom using multiple modalities to examine the same cohort of individuals. The current study aims to bring together multiple brain imaging modalities (structural MRI, DTI, and 1H-MRS) to investigate the neural architecture in the same set of individuals (19 high-functioning adults with ASD and 18 typically developing (TD) peers). Morphometry analysis revealed increased cortical thickness in ASD participants, relative to typical controls, across the left cingulate, left pars opercularis of the inferior frontal gyrus, left inferior temporal cortex, and right precuneus, and reduced cortical thickness in right cuneus and right precentral gyrus. ASD adults also had reduced fractional anisotropy (FA) and increased radial diffusivity (RD) for two clusters on the forceps minor of the corpus callosum, revealed by DTI analyses. 1H-MRS results showed a reduction in the N-acetylaspartate/Creatine ratio in dorsal anterior cingulate cortex (dACC) in ASD participants. A decision tree classification analysis across the three modalities resulted in classification accuracy of 91.9% with FA, RD, and cortical thickness as key predictors. Examining the same cohort of adults with ASD and their TD peers, this study found alterations in cortical thickness, white matter (WM) connectivity, and neurochemical concentration in ASD. These findings underscore the potential for multimodal imaging to better inform on the neural characteristics most relevant to the disorder. PMID:25797658

  7. Genetic correlation between autistic traits and IQ in a population-based sample of twins with autism spectrum disorders (ASDs).

    PubMed

    Nishiyama, Takeshi; Taniai, Hiroko; Taniai, Hitomi; Miyachi, Taishi; Ozaki, Koken; Tomita, Makoto; Sumi, Satoshi

    2009-01-01

    Although there is accumulating evidence that intelligence quotient (IQ) indexes some aspects of the autistic spectrum disorders (ASDs), the causal relationship between autistic traits and IQ remains controversial. We examined the sources of covariation between autistic traits and IQ. As males have a four times greater risk of ASDs than females, gender-specific effects were also explored. Autistic traits and IQ were assessed in 45 twin male-male, female-female and opposite-sex pairs ascertained by the regional screening system in Nagoya, Japan. Sex-limited Cholesky structural equation models were used to decompose the correlations between autistic traits and IQ into genetic and environmental components, including sex-specific factors. Genetic correlations between autistic traits and IQ were high and not significantly different between boys and girls (-0.94 and -0.95, respectively), but genetic factors underlying the autistic traits were not entirely shared with the IQ. The individual-specific environmental correlation between autistic traits and IQ was estimated at -0.29 for boys and -0.59 for girls. There is a substantial overlap between the genetic factors that influence individual variation in autistic traits and IQ, irrespective of gender. The individual life experiences that increase autistic traits, however, have a moderate overlap with those that contribute to individual IQs.

  8. The Phenomenology and Clinical Correlates of Suicidal Thoughts and Behaviors in Youth with Autism Spectrum Disorders

    PubMed Central

    Storch, Eric A.; Sulkowski, Michael L.; Nadeau, Josh; Lewin, Adam B.; Arnold, Elysse B.; Mutch, P. Jane; Jones, Anna M.; Murphy, Tanya K.

    2013-01-01

    This study investigated the phenomenology and clinical correlates of suicidal thoughts and behaviors in youth with ASD (N=102; range=7–16 years). The presence of suicidal thoughts and behavior was assessed through the Anxiety Disorders Interview Schedule-Child and Parent Versions. Children and parents completed measures of anxiety severity, functional impairment, and behavioral and emotional problems. Approximately 11% of youth displayed suicidal thoughts and behaviors. Children with autism were more likely to have suicidal thoughts and behaviors whereas children with Asperger’s disorder were less likely. Suicidal thoughts and behaviors were associated with the presence of depression and post-traumatic stress disorder. Overall, results suggest that suicidal thoughts and behaviors are common in youth with ASD, and may be related to depression and trauma. PMID:23446993

  9. Mass spectrum and correlation functions of non-Abelian quantum magnetic monopoles

    NASA Astrophysics Data System (ADS)

    Marino, E. C.; Ramos, Rudnei O.

    1994-01-01

    The method of quantization of magnetic monopoles based on the order-disorder duality existing between the monopole operator and the Lagrangian fields is applied to the description of the quantum magnetic monopoles of 't Hooft and Polyakov in the SO(3) Georgi-Glashow model. The commutator of the monopole operator with the magnetic charge is computed explicitly, indicating that indeed the quantum monopole carries 4π/g units of magnetic charge. An explicit expression for the asymptotic behavior of the monopole correlation function is derived. From this, the mass of the quantum monopole is obtained. The tree-level result for the quantum monopole mass is shown to satisfy the Bogomol'nyi bound (Mmon>=4πM/g2) and to be within the range of values found for the energy of the classical monopole solution.

  10. The impact of highly correlated potential energy surfaces on the anharmonically corrected IR spectrum of acetonitrile

    NASA Astrophysics Data System (ADS)

    Lutz, Oliver M. D.; Rode, Bernd M.; Bonn, Günther K.; Huck, Christian W.

    2014-10-01

    This paper discusses the quality and feasibility of highly correlated ab initio techniques in a vibrational self-consistent field (VSCF) approach using acetonitrile as a model system. The topical renormalized coupled-cluster technique exploiting the similarity-transformed Hamiltonian's left eigenstates (i.e. CR-CC(2,3)) is investigated alongside the well-known Hartree-Fock (HF), Møller-Plesset second-order perturbation theory (MP2) and coupled cluster (CCSD(T)) methods. The inclusion of mode triple interactions is discussed and it is found that the use of an effective core potential (ECP) serves as a viable compromise during the highly demanding task of computing such contributions, thus enabling a grid-based evaluation of three mode interaction terms with coupled cluster techniques also for larger molecules. In this context, a previously proposed reduced coupling scheme [1] is investigated, confirming the applicability of this technique to a system exhibiting a rather complex electronic structure. A combination of Ahlrichs' triple-ζ valence polarized (TZVP) basis set with Dunning's set of core-valence correlation functions is found to deliver results in good agreement with experiment while being computationally very feasible. Since CH3CN exhibits four degenerate vibrational degrees of freedom, it serves as an ideal model system for critically assessing the qualities of the degenerate second-order perturbation theory corrected (DPT2) VSCF technique. Besides fundamental vibrations, a thorough investigation of overtone transitions and combination bands is conducted by means of comparing the results to both available and newly recorded experimental data.

  11. Highly crystalline 2D superconductors

    NASA Astrophysics Data System (ADS)

    Saito, Yu; Nojima, Tsutomu; Iwasa, Yoshihiro

    2016-12-01

    Recent advances in materials fabrication have enabled the manufacturing of ordered 2D electron systems, such as heterogeneous interfaces, atomic layers grown by molecular beam epitaxy, exfoliated thin flakes and field-effect devices. These 2D electron systems are highly crystalline, and some of them, despite their single-layer thickness, exhibit a sheet resistance more than an order of magnitude lower than that of conventional amorphous or granular thin films. In this Review, we explore recent developments in the field of highly crystalline 2D superconductors and highlight the unprecedented physical properties of these systems. In particular, we explore the quantum metallic state (or possible metallic ground state), the quantum Griffiths phase observed in out-of-plane magnetic fields and the superconducting state maintained in anomalously large in-plane magnetic fields. These phenomena are examined in the context of weakened disorder and/or broken spatial inversion symmetry. We conclude with a discussion of how these unconventional properties make highly crystalline 2D systems promising platforms for the exploration of new quantum physics and high-temperature superconductors.

  12. Extensions of 2D gravity

    SciTech Connect

    Sevrin, A.

    1993-06-01

    After reviewing some aspects of gravity in two dimensions, I show that non-trivial embeddings of sl(2) in a semi-simple (super) Lie algebra give rise to a very large class of extensions of 2D gravity. The induced action is constructed as a gauged WZW model and an exact expression for the effective action is given.

  13. Overweight and Obesity: Prevalence and Correlates in a Large Clinical Sample of Children with Autism Spectrum Disorder

    PubMed Central

    Zuckerman, Katharine E.; Hill, Alison P.; Guion, Kimberly; Voltolina, Lisa; Fombonne, Eric

    2014-01-01

    Autism Spectrum Disorders (ASDs) and childhood obesity (OBY) are rising public health concerns. This study aimed to evaluate the prevalence of overweight (OWT) and OBY in a sample of 376 Oregon children with ASD, and to assess correlates of OWT and OBY in this sample. We used descriptive statistics, bivariate, and focused multivariate analyses to determine whether socio-demographic characteristics, ASD symptoms, ASD cognitive and adaptive functioning, behavioral problems, and treatments for ASD were associated with OWT and OBY in ASD. Overall 18.1 % of children met criteria for OWT and 17.0 % met criteria for OBY. OBY was associated with sleep difficulties, melatonin use, and affective problems. Interventions that consider unique needs of children with ASD may hold promise for improving weight status among children with ASD. PMID:24488158

  14. Eye-Tracking, Autonomic, and Electrophysiological Correlates of Emotional Face Processing in Adolescents with Autism Spectrum Disorder

    PubMed Central

    Wagner, Jennifer B.; Hirsch, Suzanna B.; Vogel-Farley, Vanessa K.; Redcay, Elizabeth; Nelson, Charles A.

    2014-01-01

    Individuals with autism spectrum disorder (ASD) often have difficulty with social-emotional cues. This study examined the neural, behavioral, and autonomic correlates of emotional face processing in adolescents with ASD and typical development (TD) using eye-tracking and event-related potentials (ERPs) across two different paradigms. Scanning of faces was similar across groups in the first task, but the second task found that face-sensitive ERPs varied with emotional expressions only in TD. Further, ASD showed enhanced neural responding to non-social stimuli. In TD only, attention to eyes during eye-tracking related to faster face-sensitive ERPs in a separate task; in ASD, a significant positive association was found between autonomic activity and attention to mouths. Overall, ASD showed an atypical pattern of emotional face processing, with reduced neural differentiation between emotions and a reduced relationship between gaze behavior and neural processing of faces. PMID:22684525

  15. Mutation spectrum of phenylketonuria in Syrian population: genotype-phenotype correlation.

    PubMed

    Murad, Hossam; Dabboul, Amir; Moassas, Faten; Alasmar, Diana; Al-Achkar, Walid

    2013-10-10

    Characterization of the molecular basis of phenylketonuria (PKU) in Syria has been accomplished through the analysis of 78 unrelated chromosomes from 39 Syrian patients with PKU. Phenylalanine hydroxylase (PAH) gene mutations have been analyzed by using molecular detection methods based on the restriction fragment length polymorphism (RFLP), artificial constructed restriction sites (ACRS) PCR and direct DNA sequencing. 56.4% of the patients had cPKU. A mutation detection rate of 79.49% was achieved and sixteen different mutations were found: missense 56.25%, splice site 37.5%, and frameshift 6.25%. The predominant mutation in this population sample was p.R261Q G>A, p.F55>Lfs and p.R243Q G>A. No mutation in six PKU patients was observed. In 57.9% of patient genotypes, the metabolic phenotype could be predicted. The identification of the mutations in the PAH gene and the genotype-phenotype correlation should facilitate the evaluation of metabolic phenotypes, diagnosis, implementation of optimal dietary therapy, and determination of prognosis in the patients and genetic counseling for the patient's relatives.

  16. Neural correlates of language comprehension in autism spectrum disorders: when language conflicts with world knowledge.

    PubMed

    Tesink, Cathelijne M J Y; Buitelaar, Jan K; Petersson, Karl Magnus; van der Gaag, Rutger Jan; Teunisse, Jan-Pieter; Hagoort, Peter

    2011-04-01

    In individuals with ASD, difficulties with language comprehension are most evident when higher-level semantic-pragmatic language processing is required, for instance when context has to be used to interpret the meaning of an utterance. Until now, it is unclear at what level of processing and for what type of context these difficulties in language comprehension occur. Therefore, in the current fMRI study, we investigated the neural correlates of the integration of contextual information during auditory language comprehension in 24 adults with ASD and 24 matched control participants. Different levels of context processing were manipulated by using spoken sentences that were correct or contained either a semantic or world knowledge anomaly. Our findings demonstrated significant differences between the groups in inferior frontal cortex that were only present for sentences with a world knowledge anomaly. Relative to the ASD group, the control group showed significantly increased activation in left inferior frontal gyrus (LIFG) for sentences with a world knowledge anomaly compared to correct sentences. This effect possibly indicates reduced integrative capacities of the ASD group. Furthermore, world knowledge anomalies elicited significantly stronger activation in right inferior frontal gyrus (RIFG) in the control group compared to the ASD group. This additional RIFG activation probably reflects revision of the situation model after new, conflicting information. The lack of recruitment of RIFG is possibly related to difficulties with exception handling in the ASD group.

  17. Genetic spectrum and clinical correlates of somatic mutations in aldosterone-producing adenoma.

    PubMed

    Fernandes-Rosa, Fabio Luiz; Williams, Tracy Ann; Riester, Anna; Steichen, Olivier; Beuschlein, Felix; Boulkroun, Sheerazed; Strom, Tim M; Monticone, Silvia; Amar, Laurence; Meatchi, Tchao; Mantero, Franco; Cicala, Maria-Verena; Quinkler, Marcus; Fallo, Francesco; Allolio, Bruno; Bernini, Giampaolo; Maccario, Mauro; Giacchetti, Gilberta; Jeunemaitre, Xavier; Mulatero, Paolo; Reincke, Martin; Zennaro, Maria-Christina

    2014-08-01

    Primary aldosteronism is the most common form of secondary hypertension. Somatic mutations in KCNJ5, ATP1A1, ATP2B3, and CACNA1D have been described in aldosterone-producing adenomas (APAs). Our aim was to investigate the prevalence of somatic mutations in these genes in unselected patients with APA (n=474), collected through the European Network for the Study of Adrenal Tumors. Correlations with clinical and biochemical parameters were first analyzed in a subset of 199 patients from a single center and then replicated in 2 additional centers. Somatic heterozygous KCNJ5 mutations were present in 38% (180/474) of APAs, whereas ATP1A1 mutations were found in 5.3% (25/474) and ATP2B3 mutations in 1.7% (8/474) of APAs. Previously reported somatic CACNA1D mutations as well as 10 novel CACNA1D mutations were identified in 44 of 474 (9.3%) APAs. There was no difference in the cellular composition of APAs or in CYP11B2, CYP11B1, KCNJ5, CACNA1D, or ATP1A1 gene expression in APAs across genotypes. Patients with KCNJ5 mutations were more frequently female, diagnosed younger, and with higher minimal plasma potassium concentrations compared with CACNA1D mutation carriers or noncarriers. CACNA1D mutations were associated with smaller adenomas. These associations were largely dependent on the population structure of the different centers. In conclusion, recurrent somatic mutations were identified in 54% of APAs. Young women with APAs are more likely to be KCNJ5 mutation carriers; identification of specific characteristics or surrogate biomarkers of mutation status may lead to targeted treatment options.

  18. Measurement of A Redshift-space Power Spectrum for BOSS Galaxies and the Growth Rate at Redshift 0.57

    NASA Astrophysics Data System (ADS)

    Li, Zhigang; Jing, Y. P.; Zhang, Pengjie; Cheng, Dalong

    2016-12-01

    We present a measurement of the two-dimensional (2D) redshift-space power spectrum for the Baryon Oscillation Spectroscopic Survey Data Release 11 CMASS galaxies in the northern Galactic cap based on the method developed by Jing & Börner. In this method, we first measure the 2D redshift-space correlation function and obtain the 2D power spectrum based on Fourier transform of the correlation function. The method is tested with an N-body mock galaxy catalog, which demonstrates that the method can yield an accurate and unbiased measurement of the redshift-space power spectrum given that the input 2D correlation function is correct. Compared with previous measurements in literature that are usually based on direct Fourier transform in redshift space, our method has the advantages that the window function and shot noise are fully corrected. Thus, our measurement can facilitate a direct comparison with the theoretical predictions. Our 2D power spectrum, by construction, can reproduce the 2D correlation function, and it can reproduce, for example, the 2D power spectrum of Beutler et al. accurately if ours is convolved with the window function they provided. We then develop a method to measure the structure growth rate, by separating the anisotropic redshift-space power spectrum from the isotropic real-space power spectrum. We have carefully corrected for the nonlinearities in the mapping from real space to redshift space, according to the theoretical model of Zhang et al. Finally, we obtain the measurement of structure growth rate f({z}{eff})σ 8({z}{eff}) = 0.438 ± 0.037 at the effective redshift {z}{eff} = 0.57. The result is useful for constraining cosmological parameters. The measurements of the 2D power spectrum will be released soon.

  19. Rapid-scan coherent 2D fluorescence spectroscopy.

    PubMed

    Draeger, Simon; Roeding, Sebastian; Brixner, Tobias

    2017-02-20

    We developed pulse-shaper-assisted coherent two-dimensional (2D) electronic spectroscopy in liquids using fluorescence detection. A customized pulse shaper facilitates shot-to-shot modulation at 1 kHz and is employed for rapid scanning over all time delays. A full 2D spectrum with 15 × 15 pixels is obtained in approximately 6 s of measurement time (plus further averaging if needed). Coherent information is extracted from the incoherent fluorescence signal via 27-step phase cycling. We exemplify the technique on cresyl violet in ethanol and recover literature-known oscillations as a function of population time. Signal-to-noise behavior is analyzed as a function of the amount of averaging. Rapid scanning provides a 2D spectrum with a root-mean-square error of < 0.05 after 1 min of measurement time.

  20. On the spectrum of 2D conformal field theories

    NASA Astrophysics Data System (ADS)

    Gepner, Doron

    Possible unitary statistical models and SU(2) current algebra theories are classified up to certain "levels" of the Virasoro and Kac-Moody algebras. A connection that is found between the Virasoro and SU(2) Kac-Moody characters is used to generate unitary statistical models from the SU(2) theories. Using the "fusion rules" of the operator product algebra of these theories, we are able to check the consistency of the solutions, and to write down their operator product algebra. The connection between the two algebras extends also to the fusion rules.

  1. Dominant 2D magnetic turbulence in the solar wind

    NASA Technical Reports Server (NTRS)

    Bieber, John W.; Wanner, Wolfgang; Matthaeus, William H.

    1995-01-01

    There have been recent suggestions that solar wind magnetic turbulence may be a composite of slab geometry (wavevector aligned with the mean magnetic field) and 2D geometry (wavevectors perpendicular to the mean field). We report results of two new tests of this hypothesis using Helios measurements of inertial ranged magnetic spectra in the solar wind. The first test is based upon a characteristic difference between perpendicular and parallel reduced power spectra which is expected for the 2D component but not for the slab component. The second test examines the dependence of power spectrum density upon the magnetic field angle (i.e., the angle between the mean magnetic field and the radial direction), a relationship which is expected to be in opposite directions for the slab and 2D components. Both tests support the presence of a dominant (approximately 85 percent by energy) 2D component in solar wind magnetic turbulence.

  2. Inter-ethnic differences in genetic polymorphisms of xenobiotic-metabolizing enzymes (CYP1A1, CYP2D6, NAT1 and NAT2) in healthy populations: correlation with the functional in silico prediction.

    PubMed

    Khlifi, Rim; Ben Salah, Ghada; Chakroun, Amine; Hamza-Chaffai, Amel; Rebai, Ahmed

    2014-09-01

    Several studies have shown that many polymorphisms of the xenobiotic-metabolizing enzymes (XME) affect either enzymatic functions or are associated with various aspects of human health. Owing to the presence of these single nucleotide variants (SNVs), differences in detoxification capacity have been observed between many ethnicities. The aim of this investigation was to study the prevalence of four polymorphisms in XME among various ethnic groups. Attention was focused on polymorphisms of CYP2D6 (rs1058172, G>A, p.Arg365His), CYP1A1 (rs4646421, c.-26-728C>T), NAT1 (rs4921880, c.-85-1014T>A) and NAT2 (rs1208, A>G, p.Arg268Lys). These polymorphisms were analyzed in 261 healthy Tunisians individuals in comparison with different ethnic backgrounds from hapmap database. In addition, in silico functional prediction was also performed to determine the loss of function variants. Our results demonstrated that population's origins widely affect the genetic variability of XME enzymes and Tunisians show a characteristic pattern. In silico predictions showed a deleterious effect for p.Arg268Lys substitution on CYP2D6 function, findings confirmed its key role played in cancer susceptibility. These data show that detoxification genes structures depend on the studied population. This suggests that ethnic differences impact on disease risk or response to drugs and therefore should be taken into consideration in genetic association studies focusing on XME enzymes. Our results provide the first report on these SNV in Tunisian population and could be useful for further epidemiological investigations including targeted therapy.

  3. Characterization of spectrum, de novo rate and genotype-phenotype correlation of dominant GJB2 mutations in Chinese hans.

    PubMed

    Pang, Xiuhong; Chai, Yongchuan; Sun, Lianhua; Chen, Dongye; Chen, Ying; Zhang, Zhihua; Wu, Hao; Yang, Tao

    2014-01-01

    Dominant mutations in GJB2 may lead to various degrees of sensorineural hearing impairment and/or hyperproliferative epidermal disorders. So far studies of dominant GJB2 mutations were mostly limited to case reports of individual patients and families. In this study, we identified 7 families, 11 subjects with dominant GJB2 mutations by sequencing of GJB2 in 2168 Chinese Han probands with sensorineural hearing impairment and characterized the associated spectrum, de novo rate and genotype-phenotype correlation. We identified p.R75Q, p.R75W and p.R184Q as the most frequent dominant GJB2 mutations among Chinese Hans, which had a very high de novo rate (71% of probands). A majority (10/11) of subjects carrying dominant GJB2 mutations exhibited palmoplantar keratoderma in addition to hearing impairment. In two families segregated with additional c.235delC or p.V37I mutations of GJB2, family members with the compound heterozygous mutations exhibited more severe phenotype than those with single dominant GJB2 mutation. Our study suggested that the high de novo mutation rate gives rise to a significant portion of dominant GJB2 mutations. The severity of the hearing and epidermal phenotypes associated with dominant GJB2 mutations may be modified by additional recessive mutations of GJB2.

  4. COPD is associated with production of autoantibodies to a broad spectrum of self-antigens, correlative with disease phenotype

    PubMed Central

    Packard, Thomas A.; Li, Quan Z.; Cosgrove, Gregory P.; Bowler, Russell P.

    2014-01-01

    The role of autoimmune pathology in development and progression of chronic obstructive pulmonary disease (COPD) is becoming increasingly appreciated. In this study, we identified serum autoantibody reactivities associated with chronic bronchitis or emphysema, as well as systemic autoimmunity and associated lung disease. Using autoantigen array analysis, we demonstrated that COPD patients produce autoantibodies reactive to a broad spectrum of self-antigens. Further, the level and reactivities of these antibodies, or autoantibody profile, correlated with disease phenotype. Patients with emphysema produced autoantibodies of higher titer and reactive to an increased number of array antigens. Strikingly, the autoantibody reactivities observed in emphysema were increased over those detected in rheumatoid arthritis patients, and included similar reactivities to those associated with lupus. These findings raise the possibility that autoantibody profiles may be used to determine COPD risk, as well as provide a diagnostic and prognostic tool. They shed light on the heterogeneity of autoantibody reactivities associated with COPD phenotype and could be of use in the personalization of medical treatment, including determining and monitoring therapeutic interventions. PMID:22941590

  5. Mutation Spectrum in the Large GTPase Dynamin 2, and Genotype–Phenotype Correlation in Autosomal Dominant Centronuclear Myopathy

    PubMed Central

    Böhm, Johann; Biancalana, Valérie; DeChene, Elizabeth T.; Bitoun, Marc; Pierson, Christopher R.; Schaefer, Elise; Karasoy, Hatice; Dempsey, Melissa A.; Klein, Fabrice; Dondaine, Nicolas; Kretz, Christine; Haumesser, Nicolas; Poirson, Claire; Toussaint, Anne; Greenleaf, Rebecca S.; Barger, Melissa A.; Mahoney, Lane J.; Kang, Peter B.; Zanoteli, Edmar; Vissing, John; Witting, Nanna; Echaniz-Laguna, Andoni; Wallgren-Pettersson, Carina; Dowling, James; Merlini, Luciano; Oldfors, Anders; Ousager, Lilian Bomme; Melki, Judith; Krause, Amanda; Jern, Christina; Oliveira, Acary S. B.; Petit, Florence; Jacquette, Aurélia; Chaussenot, Annabelle; Mowat, David; Leheup, Bruno; Cristofano, Michele; Aldea, Juan José Poza; Michel, Fabrice; Furby, Alain; Llona, Jose E. Barcena; Van Coster, Rudy; Bertini, Enrico; Urtizberea, Jon Andoni; Drouin-Garraud, Valérie; Béroud, Christophe; Prudhon, Bernard; Bedford, Melanie; Mathews, Katherine; Erby, Lori A. H.; Smith, Stephen A.; Roggenbuck, Jennifer; Crowe, Carol A.; Spitale, Allison Brennan; Johal, Sheila C.; Amato, Anthony A.; Demmer, Laurie A.; Jonas, Jessica; Darras, Basil T.; Bird, Thomas D.; Laurino, Mercy; Welt, Selman I.; Trotter, Cynthia; Guicheney, Pascale; Das, Soma; Mandel, Jean-Louis; Beggs, Alan H.; Laporte, Jocelyn

    2012-01-01

    Centronuclear myopathy (CNM) is a genetically heterogeneous disorder associated with general skeletal muscle weakness, type I fiber predominance and atrophy, and abnormally centralized nuclei. Autosomal dominant CNM is due to mutations in the large GTPase dynamin 2 (DNM2), a mechanochemical enzyme regulating cytoskeleton and membrane trafficking in cells. To date, 40 families with CNM-related DNM2 mutations have been described, and here we report 60 additional families encompassing a broad genotypic and phenotypic spectrum. In total, 18 different mutations are reported in 100 families and our cohort harbors nine known and four new mutations, including the first splice-site mutation. Genotype–phenotype correlation hypotheses are drawn from the published and new data, and allow an efficient screening strategy for molecular diagnosis. In addition to CNM, dissimilar DNM2 mutations are associated with Charcot–Marie–Tooth (CMT) peripheral neuropathy (CMTD1B and CMT2M), suggesting a tissue-specific impact of the mutations. In this study, we discuss the possible clinical overlap of CNM and CMT, and the biological significance of the respective mutations based on the known functions of dynamin 2 and its protein structure. Defects in membrane trafficking due to DNM2 mutations potentially represent a common pathological mechanism in CNM and CMT. PMID:22396310

  6. Aggressive Behavior Problems in Children with Autism Spectrum Disorders: Prevalence and Correlates in a Large Clinical Sample

    PubMed Central

    Hill, Alison Presmanes; Zuckerman, Katharine E.; Hagen, Arlene D.; Kriz, Daniel J.; Duvall, Susanne W.; van Santen, Jan; Nigg, Joel; Fair, Damien; Fombonne, Eric

    2014-01-01

    Aggressive behavior problems (ABP) are frequent yet poorly understood in children with Autism Spectrum Disorders (ASD) and are likely to co-vary significantly with comorbid problems. We examined the prevalence and sociodemographic correlates of ABP in a clinical sample of children with ASD (N = 400; 2–16.9 years). We also investigated whether children with ABP experience more intensive medical interventions, greater impairments in behavioral functioning, and more severe comorbid problems than children with ASD who do not have ABP. One in four children with ASD had Child Behavior Checklist scores on the Aggressive Behavior scale in the clinical range (T-scores ≥ 70). Sociodemographic factors (age, gender, parent education, race, ethnicity) were unrelated to ABP status. The presence of ABP was significantly associated with increased use of psychotropic drugs and melatonin, lower cognitive functioning, lower ASD severity, and greater comorbid sleep, internalizing, and attention problems. In multivariate models, sleep, internalizing, and attention problems were most strongly associated with ABP. These comorbid problems may hold promise as targets for treatment to decrease aggressive behavior and proactively identify high-risk profiles for prevention. PMID:25221619

  7. A Doppler Transient Model Based on the Laplace Wavelet and Spectrum Correlation Assessment for Locomotive Bearing Fault Diagnosis

    PubMed Central

    Shen, Changqing; Liu, Fang; Wang, Dong; Zhang, Ao; Kong, Fanrang; Tse, Peter W.

    2013-01-01

    The condition of locomotive bearings, which are essential components in trains, is crucial to train safety. The Doppler effect significantly distorts acoustic signals during high movement speeds, substantially increasing the difficulty of monitoring locomotive bearings online. In this study, a new Doppler transient model based on the acoustic theory and the Laplace wavelet is presented for the identification of fault-related impact intervals embedded in acoustic signals. An envelope spectrum correlation assessment is conducted between the transient model and the real fault signal in the frequency domain to optimize the model parameters. The proposed method can identify the parameters used for simulated transients (periods in simulated transients) from acoustic signals. Thus, localized bearing faults can be detected successfully based on identified parameters, particularly period intervals. The performance of the proposed method is tested on a simulated signal suffering from the Doppler effect. Besides, the proposed method is used to analyze real acoustic signals of locomotive bearings with inner race and outer race faults, respectively. The results confirm that the periods between the transients, which represent locomotive bearing fault characteristics, can be detected successfully. PMID:24253191

  8. Tumor necrosis factor-alpha expression in peripheral blood mononuclear cells correlates with early childhood social interaction in autism spectrum disorder.

    PubMed

    Makinodan, Manabu; Iwata, Keiko; Ikawa, Daisuke; Yamashita, Yasunori; Yamamuro, Kazuhiko; Toritsuka, Michihiro; Kimoto, Sohei; Okumura, Kazuki; Yamauchi, Takahira; Yoshino, Hiroki; Tsujii, Masatsugu; Sugiyama, Toshiro; Tsuchiya, Kenji; Mori, Norio; Matsuzaki, Hideo; Kishimoto, Toshifumi

    2017-03-01

    Autism spectrum disorder is a neurodevelopmental disorder characterized by impaired social interaction, poor communication skills, and repetitive/restrictive behaviors. Elevated blood levels of pro-inflammatory cytokines have been reported in subjects with autism spectrum disorder. On the other hand, early childhood adverse experience also increases blood levels of these cytokines. Since social experience of children with autism spectrum disorder is generally unlike to typically developing children, we hypothesized that social interaction during childhood contribute to pro-inflammatory cytokine expression in subjects with autism spectrum disorder. We compared revised Autism Diagnostic Interview scores and expression levels of pro-inflammatory cytokines in peripheral blood mononuclear cells of subjects with autism spectrum disorder (n = 30). The score of domain A on the revised Autism Diagnostic Interview, indicating social interaction impairment in early childhood, was negatively correlated with tumor necrosis factor-α mRNA expression level in peripheral blood mononuclear cells but not interleukin-1β or -6. Consistently, tumor necrosis factor-α mRNA expression was markedly low in subjects with autism spectrum disorder compared to typically developing children who presumably experienced the regular levels of social interaction. These findings suggest that the low blood levels of tumor necrosis factor-α mRNA in subjects with autism spectrum disorder might be due to impaired social interaction in early childhood.

  9. [Preliminary analysis on spectrum-efficient correlation model for anti-influenza virus of Lonicerae Japonicae Flos by partial least squares method].

    PubMed

    Mi, Hui-juan; Wang, Young-xiang; Meng, Jin; Wang, Xiu-hai; Tao, Yong-hua; Wang, Zhen-zhon

    2015-12-01

    Forty batches of Lonicerae Japonica Fse i collected extensively and prepared as the test solution. Their chromatographic fingerprints and anti-influenza virus IC50 value (half maximal inhibitory concentration) were determined respectively. Then Unscrambler software was used, and spectrum-efficient correlation analysis was done for chromatographic fingerprints data and IC50 data by partial least squares regression method, to establish spectrum-efficient correlation model for anti-influenza virus of Lonicerae Japonicae Flos. Then the other 10 batches of Lonicerae Japonicae Flos were used to verify the model and explore the adaptability of this spectrum-efficient correlation model based on partial least squares regression method. The mathematical model obtained R2 of 0.969489 and RM-SEC of 0.070691 for calibration set; R2 of 0.959042 and RMSECV of 0.084005 for cross validation set. The verification experiment results showed that the relative error between the predicted values and measured values was within 10% in all 10 hatches, and within 5% in 80% of them. The results showed that the established spectrum-efficient correlation model could be used to evaluate the biological activity of anti-influenza virus of Lonicerae Japonicae Flos by determining its HPLC fingerprints.

  10. Fluoxetine- and norfluoxetine-mediated complex drug-drug interactions: in vitro to in vivo correlation of effects on CYP2D6, CYP2C19, and CYP3A4.

    PubMed

    Sager, J E; Lutz, J D; Foti, R S; Davis, C; Kunze, K L; Isoherranen, N

    2014-06-01

    Fluoxetine and its circulating metabolite norfluoxetine comprise a complex multiple-inhibitor system that causes reversible or time-dependent inhibition of the cytochrome P450 (CYP) family members CYP2D6, CYP3A4, and CYP2C19 in vitro. Although significant inhibition of all three enzymes in vivo was predicted, the areas under the concentration-time curve (AUCs) for midazolam and lovastatin were unaffected by 2-week dosing of fluoxetine, whereas the AUCs of dextromethorphan and omeprazole were increased by 27- and 7.1-fold, respectively. This observed discrepancy between in vitro risk assessment and in vivo drug-drug interaction (DDI) profile was rationalized by time-varying dynamic pharmacokinetic models that incorporated circulating concentrations of fluoxetine and norfluoxetine enantiomers, mutual inhibitor-inhibitor interactions, and CYP3A4 induction. The dynamic models predicted all DDIs with less than twofold error. This study demonstrates that complex DDIs that involve multiple mechanisms, pathways, and inhibitors with their metabolites can be predicted and rationalized via characterization of all the inhibitory species in vitro.

  11. 2D quasiperiodic plasmonic crystals

    PubMed Central

    Bauer, Christina; Kobiela, Georg; Giessen, Harald

    2012-01-01

    Nanophotonic structures with irregular symmetry, such as quasiperiodic plasmonic crystals, have gained an increasing amount of attention, in particular as potential candidates to enhance the absorption of solar cells in an angular insensitive fashion. To examine the photonic bandstructure of such systems that determines their optical properties, it is necessary to measure and model normal and oblique light interaction with plasmonic crystals. We determine the different propagation vectors and consider the interaction of all possible waveguide modes and particle plasmons in a 2D metallic photonic quasicrystal, in conjunction with the dispersion relations of a slab waveguide. Using a Fano model, we calculate the optical properties for normal and inclined light incidence. Comparing measurements of a quasiperiodic lattice to the modelled spectra for angle of incidence variation in both azimuthal and polar direction of the sample gives excellent agreement and confirms the predictive power of our model. PMID:23209871

  12. Valleytronics in 2D materials

    NASA Astrophysics Data System (ADS)

    Schaibley, John R.; Yu, Hongyi; Clark, Genevieve; Rivera, Pasqual; Ross, Jason S.; Seyler, Kyle L.; Yao, Wang; Xu, Xiaodong

    2016-11-01

    Semiconductor technology is currently based on the manipulation of electronic charge; however, electrons have additional degrees of freedom, such as spin and valley, that can be used to encode and process information. Over the past several decades, there has been significant progress in manipulating electron spin for semiconductor spintronic devices, motivated by potential spin-based information processing and storage applications. However, experimental progress towards manipulating the valley degree of freedom for potential valleytronic devices has been limited until very recently. We review the latest advances in valleytronics, which have largely been enabled by the isolation of 2D materials (such as graphene and semiconducting transition metal dichalcogenides) that host an easily accessible electronic valley degree of freedom, allowing for dynamic control.

  13. Unparticle example in 2D.

    PubMed

    Georgi, Howard; Kats, Yevgeny

    2008-09-26

    We discuss what can be learned about unparticle physics by studying simple quantum field theories in one space and one time dimension. We argue that the exactly soluble 2D theory of a massless fermion coupled to a massive vector boson, the Sommerfield model, is an interesting analog of a Banks-Zaks model, approaching a free theory at high energies and a scale-invariant theory with nontrivial anomalous dimensions at low energies. We construct a toy standard model coupling to the fermions in the Sommerfield model and study how the transition from unparticle behavior at low energies to free particle behavior at high energies manifests itself in interactions with the toy standard model particles.

  14. Remarks on thermalization in 2D CFT

    NASA Astrophysics Data System (ADS)

    de Boer, Jan; Engelhardt, Dalit

    2016-12-01

    We revisit certain aspects of thermalization in 2D conformal field theory (CFT). In particular, we consider similarities and differences between the time dependence of correlation functions in various states in rational and non-rational CFTs. We also consider the distinction between global and local thermalization and explain how states obtained by acting with a diffeomorphism on the ground state can appear locally thermal, and we review why the time-dependent expectation value of the energy-momentum tensor is generally a poor diagnostic of global thermalization. Since all 2D CFTs have an infinite set of commuting conserved charges, generic initial states might be expected to give rise to a generalized Gibbs ensemble rather than a pure thermal ensemble at late times. We construct the holographic dual of the generalized Gibbs ensemble and show that, to leading order, it is still described by a Banados-Teitelboim-Zanelli black hole. The extra conserved charges, while rendering c <1 theories essentially integrable, therefore seem to have little effect on large-c conformal field theories.

  15. The agreement between 3D, standard 2D and triplane 2D speckle tracking: effects of image quality and 3D volume rate.

    PubMed

    Trache, Tudor; Stöbe, Stephan; Tarr, Adrienn; Pfeiffer, Dietrich; Hagendorff, Andreas

    2014-12-01

    Comparison of 3D and 2D speckle tracking performed on standard 2D and triplane 2D datasets of normal and pathological left ventricular (LV) wall-motion patterns with a focus on the effect that 3D volume rate (3DVR), image quality and tracking artifacts have on the agreement between 2D and 3D speckle tracking. 37 patients with normal LV function and 18 patients with ischaemic wall-motion abnormalities underwent 2D and 3D echocardiography, followed by offline speckle tracking measurements. The values of 3D global, regional and segmental strain were compared with the standard 2D and triplane 2D strain values. Correlation analysis with the LV ejection fraction (LVEF) was also performed. The 3D and 2D global strain values correlated good in both normally and abnormally contracting hearts, though systematic differences between the two methods were observed. Of the 3D strain parameters, the area strain showed the best correlation with the LVEF. The numerical agreement of 3D and 2D analyses varied significantly with the volume rate and image quality of the 3D datasets. The highest correlation between 2D and 3D peak systolic strain values was found between 3D area and standard 2D longitudinal strain. Regional wall-motion abnormalities were similarly detected by 2D and 3D speckle tracking. 2DST of triplane datasets showed similar results to those of conventional 2D datasets. 2D and 3D speckle tracking similarly detect normal and pathological wall-motion patterns. Limited image quality has a significant impact on the agreement between 3D and 2D numerical strain values.

  16. The Broad Autism (Endo)Phenotype: Neurostructural and Neurofunctional Correlates in Parents of Individuals with Autism Spectrum Disorders

    PubMed Central

    Billeci, Lucia; Calderoni, Sara; Conti, Eugenia; Gesi, Camilla; Carmassi, Claudia; Dell'Osso, Liliana; Cioni, Giovanni; Muratori, Filippo; Guzzetta, Andrea

    2016-01-01

    Autism Spectrum Disorders (ASD) are a set of neurodevelopmental disorders with an early-onset and a strong genetic component in their pathogenesis. According to genetic and epidemiological data, ASD relatives present personality traits similar to, but not as severe as the defining features of ASD, which have been indicated as the “Broader Autism Phenotype” (BAP). BAP features seem to be more prevalent in first-degree relatives of individuals with ASD than in the general population. Characterizing brain profiles of relatives of autistic probands may help to understand ASD endophenotype. The aim of this review was to provide an up-to-date overview of research findings on the neurostructural and neurofunctional substrates in parents of individuals with ASD (pASD). The primary hypothesis was that, like for the behavioral profile, the pASD express an intermediate neurobiological pattern between ASD individuals and healthy controls. The 13 reviewed studies evaluated structural magnetic resonance imaging (MRI) brain volumes, chemical signals using magnetic resonance spectroscopy (MRS), task-related functional activation by functional magnetic resonance imaging (fMRI), electroencephalography (EEG), or magnetoencephalography (MEG) in pASD.The studies showed that pASD are generally different from healthy controls at a structural and functional level despite often not behaviorally impaired. More atypicalities in neural patterns of pASD seem to be associated with higher scores at BAP assessment. Some of the observed atypicalities are the same of the ASD probands. In addition, the pattern of neural correlates in pASD resembles that of adult individuals with ASD, or it is specific, possibly due to a compensatory mechanism. Future studies should ideally include a group of pASD and HC with their ASD and non-ASD probands respectively. They should subgrouping the pASD according to the BAP scores, considering gender as a possible confounding factor, and correlating these scores

  17. Frontiers of Two-Dimensional Correlation Spectroscopy. Part 1. New concepts and noteworthy developments

    NASA Astrophysics Data System (ADS)

    Noda, Isao

    2014-07-01

    A comprehensive survey review of new and noteworthy developments, which are advancing forward the frontiers in the field of 2D correlation spectroscopy during the last four years, is compiled. This review covers books, proceedings, and review articles published on 2D correlation spectroscopy, a number of significant conceptual developments in the field, data pretreatment methods and other pertinent topics, as well as patent and publication trends and citation activities. Developments discussed include projection 2D correlation analysis, concatenated 2D correlation, and correlation under multiple perturbation effects, as well as orthogonal sample design, predicting 2D correlation spectra, manipulating and comparing 2D spectra, correlation strategy based on segmented data blocks, such as moving-window analysis, features like determination of sequential order and enhanced spectral resolution, statistical 2D spectroscopy using covariance and other statistical metrics, hetero-correlation analysis, and sample-sample correlation technique. Data pretreatment operations prior to 2D correlation analysis are discussed, including the correction for physical effects, background and baseline subtraction, selection of reference spectrum, normalization and scaling of data, derivatives spectra and deconvolution technique, and smoothing and noise reduction. Other pertinent topics include chemometrics and statistical considerations, peak position shift phenomena, variable sampling increments, computation and software, display schemes, such as color coded format, slice and power spectra, tabulation, and other schemes.

  18. 2D materials for photon conversion and nanophotonics

    NASA Astrophysics Data System (ADS)

    Tahersima, Mohammad H.; Sorger, Volker J.

    2015-09-01

    The field of two-dimensional (2D) materials has the potential to enable unique applications across a wide range of the electromagnetic spectrum. While 2D-layered materials hold promise for next-generation photon-conversion intrinsic limitations and challenges exist that shall be overcome. Here we discuss the intrinsic limitations as well as application opportunities of this new class of materials, and is sponsored by the NSF program Designing Materials to Revolutionize and Engineer our Future (DMREF) program, which links to the President's Materials Genome Initiative. We present general material-related details for photon conversion, and show that taking advantage of the mechanical flexibility of 2D materials by rolling MoS2/graphene/hexagonal boron nitride stack to a spiral solar cell allows for solar absorption up to 90%.

  19. Applications of Doppler Tomography in 2D and 3D

    NASA Astrophysics Data System (ADS)

    Richards, M.; Budaj, J.; Agafonov, M.; Sharova, O.

    2010-12-01

    Over the past few years, the applications of Doppler tomography have been extended beyond the usual calculation of 2D velocity images of circumstellar gas flows. This technique has now been used with the new Shellspec spectrum synthesis code to demonstrate the effective modeling of the accretion disk and gas stream in the TT Hya Algol binary. The 2D tomography procedure projects all sources of emission onto a single central (Vx, Vy) velocity plane even though the gas is expected to flow beyond that plane. So, new 3D velocity images were derived with the Radioastronomical Approach method by assuming a grid of Vz values transverse to the central 2D plane. The 3D approach has been applied to the U CrB and RS Vul Algol-type binaries to reveal substantial flow structures beyond the central velocity plane.

  20. Dynamic UltraFast 2D EXchange SpectroscopY (UF-EXSY) of hyperpolarized substrates

    PubMed Central

    Swisher, Christine Leon; Koelsch, Bertram; Sukumar, Subramianam; Sriram, Renuka; Santos, Romelyn Delos; Wang, Zhen Jane; Kurhanewicz, John; Vigneron, Daniel; Larson, Peder

    2015-01-01

    In this work, we present a new ultrafast method for acquiring dynamic 2D EXchange SpectroscopY (EXSY) within a single acquisition. This technique reconstructs two-dimensional EXSY spectra from one-dimensional spectra based on the phase accrual during echo times. The Ultrafast-EXSY acquisition overcomes long acquisition times typically needed to acquire 2D NMR data by utilizing sparsity and phase dependence to dramatically undersample in the indirect time dimension. This allows for the acquisition of the 2D spectrum within a single shot. We have validated this method in simulations and hyperpolarized enzyme assay experiments separating the dehydration of pyruvate and lactate-to-pyruvate conversion. In a renal cell carcinoma cell (RCC) line, bidirectional exchange was observed. This new technique revealed decreased conversion of lactate-to-pyruvate with high expression of monocarboxylate transporter 4 (MCT4), known to correlate with aggressive cancer phenotypes. We also showed feasibility of this technique in vivo in a RCC model where bidirectional exchange was observed for pyruvate–lactate, pyruvate–alanine, and pyruvate–hydrate and were resolved in time. Broadly, the technique is well suited to investigate the dynamics of multiple exchange pathways and applicable to hyperpolarized substrates where chemical exchange has shown great promise across a range of disciplines. PMID:26117655

  1. Dynamic UltraFast 2D EXchange SpectroscopY (UF-EXSY) of hyperpolarized substrates

    NASA Astrophysics Data System (ADS)

    Leon Swisher, Christine; Koelsch, Bertram; Sukumar, Subramianam; Sriram, Renuka; Santos, Romelyn Delos; Wang, Zhen Jane; Kurhanewicz, John; Vigneron, Daniel; Larson, Peder

    2015-08-01

    In this work, we present a new ultrafast method for acquiring dynamic 2D EXchange SpectroscopY (EXSY) within a single acquisition. This technique reconstructs two-dimensional EXSY spectra from one-dimensional spectra based on the phase accrual during echo times. The Ultrafast-EXSY acquisition overcomes long acquisition times typically needed to acquire 2D NMR data by utilizing sparsity and phase dependence to dramatically undersample in the indirect time dimension. This allows for the acquisition of the 2D spectrum within a single shot. We have validated this method in simulations and hyperpolarized enzyme assay experiments separating the dehydration of pyruvate and lactate-to-pyruvate conversion. In a renal cell carcinoma cell (RCC) line, bidirectional exchange was observed. This new technique revealed decreased conversion of lactate-to-pyruvate with high expression of monocarboxylate transporter 4 (MCT4), known to correlate with aggressive cancer phenotypes. We also showed feasibility of this technique in vivo in a RCC model where bidirectional exchange was observed for pyruvate-lactate, pyruvate-alanine, and pyruvate-hydrate and were resolved in time. Broadly, the technique is well suited to investigate the dynamics of multiple exchange pathways and applicable to hyperpolarized substrates where chemical exchange has shown great promise across a range of disciplines.

  2. Digit ratio (2D:4D) and hand preference for writing in the BBC Internet Study.

    PubMed

    Manning, J T; Peters, M

    2009-09-01

    The ratio of the length of the second to the fourth digit (2D:4D) may be negatively correlated with prenatal testosterone. Hand preference has been linked with prenatal testosterone and 2D:4D. Here we show that 2D:4D is associated with hand preference for writing in a large internet sample (n>170,000) in which participants self-reported their finger lengths. We replicated a significant association between right 2D:4D and writing hand preference (low right 2D:4D associated with left hand preference) as well as a significant correlation between writing hand preference and the difference between left and right 2D:4D or Dr-l (low Dr-l associated with left hand preference). A new significant correlation between left 2D:4D and writing hand preference was also shown (high left 2D:4D associated with left hand preference). There was a clear interaction between writing hand preference and 2D:4D: The left 2D:4D was significantly larger than the right 2D:4D in male and female left-handed writers, and the right hand 2D:4D was significantly larger than the left hand 2D:4D in male and female right-handed writers.

  3. Preliminary results of determination of chemical changes on Lingzhi or Reishi medicinal mushroom, Ganoderma lucidum (W.Curt.:Fr.)P. Karst. (higher Basidiomycetes) carried by Shenzhou I spaceship with FTIR and 2D-IR correlation spectroscopy.

    PubMed

    Choong, Yew Keong; Chen, Xiangdong; Jamal, Jamia Azdina; Wang, Qiuying; Lan, Jin

    2012-01-01

    Spaceflight represents a complex environmental condition. Space mutagenesis breeding has achieved marked results over the years. The objective of this study is to determine the chemical changes in medicinal mushroom Ganoderma lucidum cultivated after spaceflight in 1999. Fourier transform infrared (FTIR) and two-dimensional infrared (2DIR) correlation spectroscopy were used in analysis. The sample Sx and its control Cx showed the least dissimilarities in one-dimensional FTIR spectra, but absorbance of Sx is twice as high as Cx. Sx presented a clear peak at 1648 cm in 2nd derivative spectra, which could not be detected in the Cx. The 2DIR spectra showed the intensity of Sx in the range 1800-1400 cm-1 for protein is higher than the control. The sample Sx produced some carbohydrate peaks in the area of 889 cm-1 compared with the Cx. The spaceflight set up an extreme condition and caused changes of chemical properties in G. lucidum strain.

  4. Human- and computer-accessible 2D correlation data for a more reliable structure determination of organic compounds. Future roles of researchers, software developers, spectrometer managers, journal editors, reviewers, publisher and database managers toward artificial-intelligence analysis of NMR spectra.

    PubMed

    Jeannerat, Damien

    2017-01-01

    The introduction of a universal data format to report the correlation data of 2D NMR spectra such as COSY, HSQC and HMBC spectra will have a large impact on the reliability of structure determination of small organic molecules. These lists of assigned cross peaks will bridge signals found in NMR 1D and 2D spectra and the assigned chemical structure. The record could be very compact, human and computer readable so that it can be included in the supplementary material of publications and easily transferred into databases of scientific literature and chemical compounds. The records will allow authors, reviewers and future users to test the consistency and, in favorable situations, the uniqueness of the assignment of the correlation data to the associated chemical structures. Ideally, the data format of the correlation data should include direct links to the NMR spectra to make it possible to validate their reliability and allow direct comparison of spectra. In order to take the full benefits of their potential, the correlation data and the NMR spectra should therefore follow any manuscript in the review process and be stored in open-access database after publication. Keeping all NMR spectra, correlation data and assigned structures together at all time will allow the future development of validation tools increasing the reliability of past and future NMR data. This will facilitate the development of artificial intelligence analysis of NMR spectra by providing a source of data than can be used efficiently because they have been validated or can be validated by future users. Copyright © 2016 John Wiley & Sons, Ltd.

  5. Mean flow and anisotropic cascades in decaying 2D turbulence

    NASA Astrophysics Data System (ADS)

    Liu, Chien-Chia; Cerbus, Rory; Gioia, Gustavo; Chakraborty, Pinaki

    2015-11-01

    Many large-scale atmospheric and oceanic flows are decaying 2D turbulent flows embedded in a non-uniform mean flow. Despite its importance for large-scale weather systems, the affect of non-uniform mean flows on decaying 2D turbulence remains unknown. In the absence of mean flow it is well known that decaying 2D turbulent flows exhibit the enstrophy cascade. More generally, for any 2D turbulent flow, all computational, experimental and field data amassed to date indicate that the spectrum of longitudinal and transverse velocity fluctuations correspond to the same cascade, signifying isotropy of cascades. Here we report experiments on decaying 2D turbulence in soap films with a non-uniform mean flow. We find that the flow transitions from the usual isotropic enstrophy cascade to a series of unusual and, to our knowledge, never before observed or predicted, anisotropic cascades where the longitudinal and transverse spectra are mutually independent. We discuss implications of our results for decaying geophysical turbulence.

  6. NKG2D ligands as therapeutic targets

    PubMed Central

    Spear, Paul; Wu, Ming-Ru; Sentman, Marie-Louise; Sentman, Charles L.

    2013-01-01

    The Natural Killer Group 2D (NKG2D) receptor plays an important role in protecting the host from infections and cancer. By recognizing ligands induced on infected or tumor cells, NKG2D modulates lymphocyte activation and promotes immunity to eliminate ligand-expressing cells. Because these ligands are not widely expressed on healthy adult tissue, NKG2D ligands may present a useful target for immunotherapeutic approaches in cancer. Novel therapies targeting NKG2D ligands for the treatment of cancer have shown preclinical success and are poised to enter into clinical trials. In this review, the NKG2D receptor and its ligands are discussed in the context of cancer, infection, and autoimmunity. In addition, therapies targeting NKG2D ligands in cancer are also reviewed. PMID:23833565

  7. Vector correlations study of the reaction N(2D)+H2(X1Σg+)→NH(a1Δ)+H(2S) with different collision energies and reagent vibration excitations

    NASA Astrophysics Data System (ADS)

    Li, Yong-Qing; Zhang, Yong-Jia; Zhao, Jin-Feng; Zhao, Mei-Yu; Ding, Yong

    2015-11-01

    Vector correlations of the reaction are studied based on a recent DMBE-SEC PES for the first excited state of NH2 [J. Phys. Chem. A 114 9644 (2010)] by using a quasi-classical trajectory method. The effects of collision energy and the reagent initial vibrational excitation on cross section and product polarization are investigated for v = 0-5 and j = 0 states in a wide collision energy range (10-50 kcal/mol). The integral cross section could be increased by H2 vibration excitation remarkably based on the DMBE-SEC PES. The different phenomena of differential cross sections with different collision energies and reagent vibration excitations are explained. Particularly, the NH molecules are scattered mainly in the backward hemisphere at low vibration quantum number and evolve from backward to forward direction with increasing vibration quantum number, which could be explained by the fact that the vibrational excitation enlarges the H-H distance in the entrance channel, thus enhancing the probability of collision between N atom and H atom. A further study on product polarization demonstrates that the collision energy and vibrational excitation of the reagent remarkably influence the distributions of P(θr), P(ϕr), and P(θr, ϕr). Project supported by the National Natural Science Foundation of China (Grant Nos. 11474141 and 11404080), the Special Fund Based Research New Technology of Methanol conversion and Coal Instead of Oil, the China Postdoctoral Science Foundation (Grant No. 2014M550158) , the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry of China (Grant No. 2014-1685), and the Program for Liaoning Excellent Talents in University, China (Grant Nos. LJQ2015040 and LJQ2014001).

  8. Adaptive Behavior Ratings Correlate with Symptomatology and IQ among Individuals with High-Functioning Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Kenworthy, Lauren; Case, Laura; Harms, Madeline B.; Martin, Alex; Wallace, Gregory L.

    2010-01-01

    Caregiver report on the Adaptive Behavior Assessment System-II (ABAS) for 40 high-functioning individuals with Autism Spectrum Disorders (ASD) and 30 typically developing (TD) individuals matched for age, IQ, and sex ratio revealed global adaptive behavior deficits in ASD, with social skills impairments particularly prominent. Within the ASD…

  9. A novel improved method for analysis of 2D diffusion relaxation data—2D PARAFAC-Laplace decomposition

    NASA Astrophysics Data System (ADS)

    Tønning, Erik; Polders, Daniel; Callaghan, Paul T.; Engelsen, Søren B.

    2007-09-01

    This paper demonstrates how the multi-linear PARAFAC model can with advantage be used to decompose 2D diffusion-relaxation correlation NMR spectra prior to 2D-Laplace inversion to the T2- D domain. The decomposition is advantageous for better interpretation of the complex correlation maps as well as for the quantification of extracted T2- D components. To demonstrate the new method seventeen mixtures of wheat flour, starch, gluten, oil and water were prepared and measured with a 300 MHz nuclear magnetic resonance (NMR) spectrometer using a pulsed gradient stimulated echo (PGSTE) pulse sequence followed by a Carr-Purcell-Meiboom-Gill (CPMG) pulse echo train. By varying the gradient strength, 2D diffusion-relaxation data were recorded for each sample. From these double exponentially decaying relaxation data the PARAFAC algorithm extracted two unique diffusion-relaxation components, explaining 99.8% of the variation in the data set. These two components were subsequently transformed to the T2- D domain using 2D-inverse Laplace transformation and quantitatively assigned to the oil and water components of the samples. The oil component was one distinct distribution with peak intensity at D = 3 × 10 -12 m 2 s -1 and T2 = 180 ms. The water component consisted of two broad populations of water molecules with diffusion coefficients and relaxation times centered around correlation pairs: D = 10 -9 m 2 s -1, T2 = 10 ms and D = 3 × 10 -13 m 2 s -1, T2 = 13 ms. Small spurious peaks observed in the inverse Laplace transformation of original complex data were effectively filtered by the PARAFAC decomposition and thus considered artefacts from the complex Laplace transformation. The oil-to-water ratio determined by PARAFAC followed by 2D-Laplace inversion was perfectly correlated with known oil-to-water ratio of the samples. The new method of using PARAFAC prior to the 2D-Laplace inversion proved to have superior potential in analysis of diffusion-relaxation spectra, as it

  10. 2D TRIPLE in orientationally disordered samples—a means to resolve and determine relative orientation of hyperfine tensors

    NASA Astrophysics Data System (ADS)

    Goldfarb, D.; Epel, B.; Zimmermann, H.; Jeschke, G.

    2004-05-01

    The two-dimensional (2D) TRIPLE experiment provides correlations between electron-nuclear double resonance (ENDOR) frequencies that belong to the same electron-spin manifold, MS, and therefore allows to assign ENDOR lines to their specific paramagnetic centers and MS manifolds. This, in turn, also provides the relative signs of the hyperfine couplings. So far this experiment has been applied only to single crystals, where the cross-peaks in the 2D spectrum are well resolved with regular shapes. Here we introduce the application of the 2D TRIPLE experiment to orientationally disordered systems, where it can resolve overlapping powder patterns. Moreover, analysis of the shape of the cross-peaks shows that it is highly dependent on the relative orientation of the hyperfine tensors of the two nuclei contributing to this particular peak. This is done initially through a series of simulations and then demonstrated experimentally at a high field (W-band, 95 GHz). The first example concerned the 1H hyperfine tensors of the stable radical α,γ-bisdiphenylene-β-phenylallyl (BDPA) immobilized in a polystyrene matrix. Then, the experiment was applied to a more complex system, a frozen solution of Cu(II)-bis(2,2 ':6 ',2″ terpyridine) complex. There, the 2D TRIPLE experiment was combined with the variable mixing time (VMT) ENDOR experiment, which determined the absolute sign of the hyperfine couplings involved, and orientation selective ENDOR experiments. Analysis of the three experiments gave the hyperfine tensors of a few coupled protons.

  11. Quantitative 2D liquid-state NMR.

    PubMed

    Giraudeau, Patrick

    2014-06-01

    Two-dimensional (2D) liquid-state NMR has a very high potential to simultaneously determine the absolute concentration of small molecules in complex mixtures, thanks to its capacity to separate overlapping resonances. However, it suffers from two main drawbacks that probably explain its relatively late development. First, the 2D NMR signal is strongly molecule-dependent and site-dependent; second, the long duration of 2D NMR experiments prevents its general use for high-throughput quantitative applications and affects its quantitative performance. Fortunately, the last 10 years has witnessed an increasing number of contributions where quantitative approaches based on 2D NMR were developed and applied to solve real analytical issues. This review aims at presenting these recent efforts to reach a high trueness and precision in quantitative measurements by 2D NMR. After highlighting the interest of 2D NMR for quantitative analysis, the different strategies to determine the absolute concentrations from 2D NMR spectra are described and illustrated by recent applications. The last part of the manuscript concerns the recent development of fast quantitative 2D NMR approaches, aiming at reducing the experiment duration while preserving - or even increasing - the analytical performance. We hope that this comprehensive review will help readers to apprehend the current landscape of quantitative 2D NMR, as well as the perspectives that may arise from it.

  12. DISCO: Distance and Spectrum Correlation Optimization Alignment for Two Dimensional Gas Chromatography Time-of-Flight Mass Spectrometry-based Metabolomics

    PubMed Central

    Wang, Bing; Fang, Aiqin; Heim, John; Bogdanov, Bogdan; Pugh, Scott; Libardoni, Mark; Zhang, Xiang

    2010-01-01

    A novel peak alignment algorithm using a distance and spectrum correlation optimization (DISCO) method has been developed for two-dimensional gas chromatography time-of-flight mass spectrometry (GC×GC/TOF-MS) based metabolomics. This algorithm uses the output of the instrument control software, ChromaTOF, as its input data. It detects and merges multiple peak entries of the same metabolite into one peak entry in each input peak list. After a z-score transformation of metabolite retention times, DISCO selects landmark peaks from all samples based on both two-dimensional retention times and mass spectrum similarity of fragment ions measured by Pearson’s correlation coefficient. A local linear fitting method is employed in the original two-dimensional retention time space to correct retention time shifts. A progressive retention time map searching method is used to align metabolite peaks in all samples together based on optimization of the Euclidean distance and mass spectrum similarity. The effectiveness of the DISCO algorithm is demonstrated using data sets acquired under different experiment conditions and a spiked-in experiment. PMID:20476746

  13. Experimental validation of equations for 2D DIC uncertainty quantification.

    SciTech Connect

    Reu, Phillip L.; Miller, Timothy J.

    2010-03-01

    Uncertainty quantification (UQ) equations have been derived for predicting matching uncertainty in two-dimensional image correlation a priori. These equations include terms that represent the image noise and image contrast. Researchers at the University of South Carolina have extended previous 1D work to calculate matching errors in 2D. These 2D equations have been coded into a Sandia National Laboratories UQ software package to predict the uncertainty for DIC images. This paper presents those equations and the resulting error surfaces for trial speckle images. Comparison of the UQ results with experimentally subpixel-shifted images is also discussed.

  14. 1D and 2D NMR studies of isobornyl acrylate - Methyl methacrylate copolymers

    NASA Astrophysics Data System (ADS)

    Khandelwal, Deepika; Hooda, Sunita; Brar, A. S.; Shankar, Ravi

    2011-10-01

    Isobornyl acrylate - methyl methacrylate (B/M) copolymers of different compositions were synthesized by atom transfer radical polymerization (ATRP) using methyl-2-bromopropionate as an initiator and PMDETA copper complex as catalyst under nitrogen atmosphere at 70 °C. 1H NMR spectrum was used to determine the compositions of copolymer. The copolymer compositions were then used to determine the reactivity ratios of monomers. Reactivity ratios of co-monomers in B/M copolymer, determined from linear Kelen-Tudos method (KT) and non linear Error-in-Variable Method (EVM), are rB = 0.41 ± 0.11, rM = 1.11 ± 0.33 and rB = 0.52, rM = 1.31 respectively. The complete resonance assignments of 1H and 13C{ 1H} NMR spectra were carried out with the help of Distortion less Enhancement by Polarization Transfer (DEPT), two-dimensional Heteronuclear Single Quantum Coherence (HSQC). 2D HSQC assignments were further confirmed by 2D Total Correlation Spectroscopy (TOCSY). The carbonyl carbon of B and M units and methyl carbon of M unit were assigned up to triad compositional and configurational sequences whereas β-methylene carbons were assigned up to tetrad compositional and configurational sequences. Similarly the methine carbon of B unit was assigned up to pentad level. 1,3 and 1,4 bond order couplings of carbonyl carbon and quaternary carbon resonances with methine, methylene and methyl protons were studied in detail using 2D Hetero Nuclear Multiple Bond Correlation (HMBC) spectra.

  15. Annotated Bibliography of EDGE2D Use

    SciTech Connect

    J.D. Strachan and G. Corrigan

    2005-06-24

    This annotated bibliography is intended to help EDGE2D users, and particularly new users, find existing published literature that has used EDGE2D. Our idea is that a person can find existing studies which may relate to his intended use, as well as gain ideas about other possible applications by scanning the attached tables.

  16. Staring 2-D hadamard transform spectral imager

    DOEpatents

    Gentry, Stephen M.; Wehlburg, Christine M.; Wehlburg, Joseph C.; Smith, Mark W.; Smith, Jody L.

    2006-02-07

    A staring imaging system inputs a 2D spatial image containing multi-frequency spectral information. This image is encoded in one dimension of the image with a cyclic Hadamarid S-matrix. The resulting image is detecting with a spatial 2D detector; and a computer applies a Hadamard transform to recover the encoded image.

  17. Optimizing sparse sampling for 2D electronic spectroscopy

    NASA Astrophysics Data System (ADS)

    Roeding, Sebastian; Klimovich, Nikita; Brixner, Tobias

    2017-02-01

    We present a new data acquisition concept using optimized non-uniform sampling and compressed sensing reconstruction in order to substantially decrease the acquisition times in action-based multidimensional electronic spectroscopy. For this we acquire a regularly sampled reference data set at a fixed population time and use a genetic algorithm to optimize a reduced non-uniform sampling pattern. We then apply the optimal sampling for data acquisition at all other population times. Furthermore, we show how to transform two-dimensional (2D) spectra into a joint 4D time-frequency von Neumann representation. This leads to increased sparsity compared to the Fourier domain and to improved reconstruction. We demonstrate this approach by recovering transient dynamics in the 2D spectrum of a cresyl violet sample using just 25% of the originally sampled data points.

  18. Theory of propagation of spectrum and correlations of radiation in optically dense gas in the case of the closed excitation contour

    NASA Astrophysics Data System (ADS)

    Barantsev, K. A.; Litvinov, A. N.; Popov, E. N.

    2016-12-01

    This work is devoted to generalization of the semi-classical theory of interaction of broadband laser radiation with the atomic gas at the room temperature in the cell in the case of the closed excitation contour. The atomic density matrix equations and spectrum and correlations transport equations have been derived for excitation by fluctuating field with Gaussian statistics. It is shown that the spatial oscillations of radiation intensity and atomic density matrix can be excited. It was found that such medium can serve as a filter of incoherent part of the radiation.

  19. Exploration of somatosensory P50 gating in schizophrenia spectrum patients: reduced P50 amplitude correlates to social anhedonia.

    PubMed

    Arnfred, Sidse M; Chen, Andrew C N

    2004-02-15

    Originally, the hypothesis of a sensory gating defect in schizophrenia evolved from studies of somatosensory evoked potentials (SEP), although the idea has primarily been pursued in the auditory modality. Gating is the relative attenuation of amplitude following the second stimulus in a stimulus pair. Recently, SEP P50 gating was seen when recording the SEP P50 in a paradigm similar to the one used for auditory P50 gating. Hypothetically, abnormality of somatosensory information processing could be related to anhedonia, which is considered a core feature of schizophrenia. Twelve unmedicated, male, schizophrenia spectrum patients (seven schizophrenic and five schizotypal personality disorder patients) and 14 age-matched healthy men participated in recordings of pair-wise presented auditory and median nerve stimuli. The patients had smaller amplitudes of the SEP P50 at the first stimulus, but no gating defect. The reduced amplitude was particularly evident in subjects with high scores on the Revised Social Anhedonia Scale. Early somatosensory information processing seems abnormal in schizophrenia spectrum patients. This could be in agreement with the theory of loss of the benefit of regularity in schizophrenia, while the results are in-conclusive regarding sensory gating theory.

  20. Beam-Plasma Instabilities in a 2D Yukawa Lattice

    SciTech Connect

    Kyrkos, S.; Kalman, G. J.; Rosenberg, M.

    2009-06-05

    We consider a 2D Yukawa lattice of grains, with a beam of other charged grains moving in the lattice plane. In contrast to Vlasov plasmas, where the electrostatic instability excited by the beam is only longitudinal, here both longitudinal and transverse instabilities of the lattice phonons can develop. We determine and compare the transverse and longitudinal growth rates. The growth rate spectrum in wave number space exhibits remarkable gaps where no instability can develop. Depending on the system parameters, the transverse instability can be selectively excited.

  1. Fracture surfaces of heterogeneous materials: A 2D solvable model

    NASA Astrophysics Data System (ADS)

    Katzav, E.; Adda-Bedia, M.; Derrida, B.

    2007-05-01

    Using an elastostatic description of crack growth based on the Griffith criterion and the principle of local symmetry, we present a stochastic model describing the propagation of a crack tip in a 2D heterogeneous brittle material. The model ensures the stability of straight cracks and allows for the study of the roughening of fracture surfaces. When neglecting the effect of the nonsingular stress, the problem becomes exactly solvable and yields analytic predictions for the power spectrum of the paths. This result suggests an alternative to the conventional power law analysis often used in the analysis of experimental data.

  2. Dynamics of Quarks in a 2D Flux Tube

    SciTech Connect

    Koshelkin, Andrey V.; Wong, Cheuk-Yin

    2015-01-01

    On the basis of a compactification of the (3+1) into (1+1) dimensional space-time [1], the quark states inside the 2D flux tube are studied for the case of a linear transverse confining potential. The derived states are classified by both the projections of the orbital momentum and the spin along the tube direction. The spectrum of the fermion states is evaluated. It is found that the energy eigenvalues of the quarks appear to be approximately related to the square root of the eigenvalues of the two-dimensional harmonic oscillator.

  3. Palus Somni - Anomalies in the correlation of Al/Si X-ray fluorescence intensity ratios and broad-spectrum visible albedos. [lunar surface mineralogy

    NASA Technical Reports Server (NTRS)

    Clark, P. E.; Andre, C. G.; Adler, I.; Weidner, J.; Podwysocki, M.

    1976-01-01

    The positive correlation between Al/Si X-ray fluorescence intensity ratios determined during the Apollo 15 lunar mission and a broad-spectrum visible albedo of the moon is quantitatively established. Linear regression analysis performed on 246 1 degree geographic cells of X-ray fluorescence intensity and visible albedo data points produced a statistically significant correlation coefficient of .78. Three distinct distributions of data were identified as (1) within one standard deviation of the regression line, (2) greater than one standard deviation below the line, and (3) greater than one standard deviation above the line. The latter two distributions of data were found to occupy distinct geographic areas in the Palus Somni region.

  4. Matrix models of 2d gravity

    SciTech Connect

    Ginsparg, P.

    1991-01-01

    These are introductory lectures for a general audience that give an overview of the subject of matrix models and their application to random surfaces, 2d gravity, and string theory. They are intentionally 1.5 years out of date.

  5. Matrix models of 2d gravity

    SciTech Connect

    Ginsparg, P.

    1991-12-31

    These are introductory lectures for a general audience that give an overview of the subject of matrix models and their application to random surfaces, 2d gravity, and string theory. They are intentionally 1.5 years out of date.

  6. Brittle damage models in DYNA2D

    SciTech Connect

    Faux, D.R.

    1997-09-01

    DYNA2D is an explicit Lagrangian finite element code used to model dynamic events where stress wave interactions influence the overall response of the system. DYNA2D is often used to model penetration problems involving ductile-to-ductile impacts; however, with the advent of the use of ceramics in the armor-anti-armor community and the need to model damage to laser optics components, good brittle damage models are now needed in DYNA2D. This report will detail the implementation of four brittle damage models in DYNA2D, three scalar damage models and one tensor damage model. These new brittle damage models are then used to predict experimental results from three distinctly different glass damage problems.

  7. 2D/3D switchable displays

    NASA Astrophysics Data System (ADS)

    Dekker, T.; de Zwart, S. T.; Willemsen, O. H.; Hiddink, M. G. H.; IJzerman, W. L.

    2006-02-01

    A prerequisite for a wide market acceptance of 3D displays is the ability to switch between 3D and full resolution 2D. In this paper we present a robust and cost effective concept for an auto-stereoscopic switchable 2D/3D display. The display is based on an LCD panel, equipped with switchable LC-filled lenticular lenses. We will discuss 3D image quality, with the focus on display uniformity. We show that slanting the lenticulars in combination with a good lens design can minimize non-uniformities in our 20" 2D/3D monitors. Furthermore, we introduce fractional viewing systems as a very robust concept to further improve uniformity in the case slanting the lenticulars and optimizing the lens design are not sufficient. We will discuss measurements and numerical simulations of the key optical characteristics of this display. Finally, we discuss 2D image quality, the switching characteristics and the residual lens effect.

  8. 2-d Finite Element Code Postprocessor

    SciTech Connect

    Sanford, L. A.; Hallquist, J. O.

    1996-07-15

    ORION is an interactive program that serves as a postprocessor for the analysis programs NIKE2D, DYNA2D, TOPAZ2D, and CHEMICAL TOPAZ2D. ORION reads binary plot files generated by the two-dimensional finite element codes currently used by the Methods Development Group at LLNL. Contour and color fringe plots of a large number of quantities may be displayed on meshes consisting of triangular and quadrilateral elements. ORION can compute strain measures, interface pressures along slide lines, reaction forces along constrained boundaries, and momentum. ORION has been applied to study the response of two-dimensional solids and structures undergoing finite deformations under a wide variety of large deformation transient dynamic and static problems and heat transfer analyses.

  9. Chemical Approaches to 2D Materials.

    PubMed

    Samorì, Paolo; Palermo, Vincenzo; Feng, Xinliang

    2016-08-01

    Chemistry plays an ever-increasing role in the production, functionalization, processing and applications of graphene and other 2D materials. This special issue highlights a selection of enlightening chemical approaches to 2D materials, which nicely reflect the breadth of the field and convey the excitement of the individuals involved in it, who are trying to translate graphene and related materials from the laboratory into a real, high-impact technology.

  10. The Prevalence and Correlates of Involvement in the Criminal Justice System among Youth on the Autism Spectrum

    ERIC Educational Resources Information Center

    Rava, Julianna; Shattuck, Paul; Rast, Jessica; Roux, Anne

    2017-01-01

    This study examined the prevalence and correlates of involvement in the criminal justice system among a nationally representative sample of youth with autism. We examined whether youth had been stopped and questioned by police or arrested at 14-15 years old and 21-22 years old. By age 21, approximately 20% of youth with autism had been stopped and…

  11. Social-Emotional Correlates of Early Stage Social Information Processing Skills in Children With and Without Autism Spectrum Disorder.

    PubMed

    Russo-Ponsaran, Nicole M; McKown, Clark; Johnson, Jason K; Allen, Adelaide W; Evans-Smith, Bernadette; Fogg, Louis

    2015-10-01

    Difficulty processing social information is a defining feature of autism spectrum disorder (ASD). Yet the failure of children with ASD to process social information effectively is poorly understood. Using Crick and Dodge's model of social information processing (SIP), this study examined the relationship between social-emotional (SE) skills of pragmatic language, theory of mind, and emotion recognition on the one hand, and early stage SIP skills of problem identification and goal generation on the other. The study included a sample of school-aged children with and without ASD. SIP was assessed using hypothetical social situations in the context of a semistructured scenario-based interview. Pragmatic language, theory of mind, and emotion recognition were measured using direct assessments. Social thinking differences between children with and without ASD are largely differences of quantity (overall lower performance in ASD), not discrepancies in cognitive processing patterns. These data support theoretical models of the relationship between SE skills and SIP. Findings have implications for understanding the mechanisms giving rise to SIP deficits in ASD and may ultimately inform treatment development for children with ASD.

  12. SOS1 mutations in Noonan syndrome: molecular spectrum, structural insights on pathogenic effects, and genotype-phenotype correlations.

    PubMed

    Lepri, Francesca; De Luca, Alessandro; Stella, Lorenzo; Rossi, Cesare; Baldassarre, Giuseppina; Pantaleoni, Francesca; Cordeddu, Viviana; Williams, Bradley J; Dentici, Maria L; Caputo, Viviana; Venanzi, Serenella; Bonaguro, Michela; Kavamura, Ines; Faienza, Maria F; Pilotta, Alba; Stanzial, Franco; Faravelli, Francesca; Gabrielli, Orazio; Marino, Bruno; Neri, Giovanni; Silengo, Margherita Cirillo; Ferrero, Giovanni B; Torrrente, Isabella; Selicorni, Angelo; Mazzanti, Laura; Digilio, Maria C; Zampino, Giuseppe; Dallapiccola, Bruno; Gelb, Bruce D; Tartaglia, Marco

    2011-07-01

    Noonan syndrome (NS) is among the most common nonchromosomal disorders affecting development and growth. NS is caused by aberrant RAS-MAPK signaling and is genetically heterogeneous, which explains, in part, the marked clinical variability documented for this Mendelian trait. Recently, we and others identified SOS1 as a major gene underlying NS. Here, we explored further the spectrum of SOS1 mutations and their associated phenotypic features. Mutation scanning of the entire SOS1 coding sequence allowed the identification of 33 different variants deemed to be of pathological significance, including 16 novel missense changes and in-frame indels. Various mutation clusters destabilizing or altering orientation of regions of the protein predicted to contribute structurally to the maintenance of autoinhibition were identified. Two previously unappreciated clusters predicted to enhance SOS1's recruitment to the plasma membrane, thus promoting a spatial reorientation of domains contributing to inhibition, were also recognized. Genotype-phenotype analysis confirmed our previous observations, establishing a high frequency of ectodermal anomalies and a low prevalence of cognitive impairment and reduced growth. Finally, mutation analysis performed on cohorts of individuals with nonsyndromic pulmonic stenosis, atrial septal defects, and ventricular septal defects excluded a major contribution of germline SOS1 lesions to the isolated occurrence of these cardiac anomalies.

  13. SOS1 Mutations in Noonan Syndrome: Molecular Spectrum, Structural Insights on Pathogenic Effects, and Genotype–Phenotype Correlations

    PubMed Central

    Lepri, Francesca; De Luca, Alessandro; Stella, Lorenzo; Rossi, Cesare; Baldassarre, Giuseppina; Pantaleoni, Francesca; Cordeddu, Viviana; Williams, Bradley J; Dentici, Maria L; Caputo, Viviana; Venanzi, Serenella; Bonaguro, Michela; Kavamura, Ines; Faienza, Maria F; Pilotta, Alba; Stanzial, Franco; Faravelli, Francesca; Gabrielli, Orazio; Marino, Bruno; Neri, Giovanni; Silengo, Margherita Cirillo; Ferrero, Giovanni B; Torrrente, Isabella; Selicorni, Angelo; Mazzanti, Laura; Digilio, Maria C; Zampino, Giuseppe; Dallapiccola, Bruno; Gelb, Bruce D; Tartaglia, Marco

    2011-01-01

    Noonan syndrome (NS) is among the most common nonchromosomal disorders affecting development and growth. NS is caused by aberrant RAS-MAPK signaling and is genetically heterogeneous, which explains, in part, the marked clinical variability documented for this Mendelian trait. Recently, we and others identified SOS1 as a major gene underlying NS. Here, we explored further the spectrum of SOS1 mutations and their associated phenotypic features. Mutation scanning of the entire SOS1 coding sequence allowed the identification of 33 different variants deemed to be of pathological significance, including 16 novel missense changes and in-frame indels. Various mutation clusters destabilizing or altering orientation of regions of the protein predicted to contribute structurally to the maintenance of autoinhibition were identified. Two previously unappreciated clusters predicted to enhance SOS1's recruitment to the plasma membrane, thus promoting a spatial reorientation of domains contributing to inhibition, were also recognized. Genotype–phenotype analysis confirmed our previous observations, establishing a high frequency of ectodermal anomalies and a low prevalence of cognitive impairment and reduced growth. Finally, mutation analysis performed on cohorts of individuals with nonsyndromic pulmonic stenosis, atrial septal defects, and ventricular septal defects excluded a major contribution of germline SOS1 lesions to the isolated occurrence of these cardiac anomalies. Hum Mutat 32:760–772, 2011. © 2011 Wiley-Liss, Inc. PMID:21387466

  14. Instantons in 2D U(1) Higgs model and 2D CP(N-1) sigma models

    NASA Astrophysics Data System (ADS)

    Lian, Yaogang

    2007-12-01

    In this thesis I present the results of a study of the topological structures of 2D U(1) Higgs model and 2D CP N-1 sigma models. Both models have been studied using the overlap Dirac operator construction of topological charge density. The overlap operator provides a more incisive probe into the local topological structure of gauge field configurations than the traditional plaquette-based operator. In the 2D U(1) Higgs model, we show that classical instantons with finite sizes violate the negativity of topological charge correlator by giving a positive contribution to the correlator at non-zero separation. We argue that instantons in 2D U(1) Higgs model must be accompanied by large quantum fluctuations in order to solve this contradiction. In 2D CPN-1 sigma models, we observe the anomalous scaling behavior of the topological susceptibility chi t for N ≤ 3. The divergence of chi t in these models is traced to the presence of small instantons with a radius of order a (= lattice spacing), which are directly observed on the lattice. The observation of these small instantons provides detailed confirmation of Luscher's argument that such short-distance excitations, with quantized topological charge, should be the dominant topological fluctuations in CP1 and CP 2, leading to a divergent topological susceptibility in the continuum limit. For the CPN-1 models with N > 3 the topological susceptibility is observed to scale properly with the mass gap. Another topic presented in this thesis is an implementation of the Zolotarev optimal rational approximation for the overlap Dirac operator. This new implementation has reduced the time complexity of the overlap routine from O(N3 ) to O(N), where N is the total number of sites on the lattice. This opens up a door to more accurate lattice measurements in the future.

  15. Brain-reactive IgG correlates with autoimmunity in mothers of a child with an autism spectrum disorder.

    PubMed

    Brimberg, L; Sadiq, A; Gregersen, P K; Diamond, B

    2013-11-01

    It is believed that in utero environmental factors contribute to autism spectrum disorder (ASD). The goal of this study was to demonstrate, using the largest cohort reported so far, that mothers of an ASD child have an elevated frequency of anti-brain antibodies and to assess whether brain reactivity is associated with an autoimmune diathesis of the mother. We screened plasma of 2431 mothers of an ASD child from Simon Simplex Collection and plasma of 653 unselected women of child-bearing age for anti-brain antibodies using immunohistology on mouse brain. Positive and negative plasma from mothers with an ASD child were analyzed for anti-nuclear antibodies and for autoimmune disorders. Mothers of an ASD child were four times more likely to harbor anti-brain antibodies than unselected women of child-bearing age (10.5 vs 2.6%). A second cohort from The Autism Genetic Resource Exchange with multiplex families displayed an 8.8% prevalence of anti-brain antibodies in the mothers of these families. Fifty-three percent of these mothers with anti-brain antibodies also exhibited anti-nuclear autoantibodies compared with 13.4% of mothers of an ASD child without anti-brain antibodies and 15% of control women of child-bearing age. The analysis of ASD mothers with brain-reactive antibodies also revealed an increased prevalence of autoimmune diseases, especially rheumatoid arthritis and systemic lupus erythematosus. This study provides robust evidence that brain-reactive antibodies are increased in mothers of an ASD child and may be associated with autoimmunity. The current study serves as a benchmark and justification for studying the potential pathogenicity of these antibodies on the developing brain. The detailed characterization of the specificity of these antibodies will provide practical benefits for the management and prevention of this disorder.

  16. 2D FT-IR Study of Compositional and Structural Change in Developing Cotton Fibers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two-dimensional (2D) correlation analysis was applied to characterize the ATR spectral intensity fluctuations of immature and mature cotton fibers. Prior to 2D analysis, the spectra were leveled to zero at the peak intensity of 1800 cm-1 and then were normalized at the peak intensity of 660 cm-1 to ...

  17. Similarity of jet radiation between flat spectrum radio quasars and GeV narrow-line Seyfert 1 galaxies: a universal δ-L c correlation

    NASA Astrophysics Data System (ADS)

    Zhu, Yong-Kai; Zhang, Jin; Zhang, Hai-Ming; Liang, En-Wei; Yan, Da-Hai; Cui, Wei; Zhang, Shuang-Nan

    2016-11-01

    By modeling the broadband spectral energy distributions (SEDs) of a typical flat spectrum radio quasar (FSRQ, 3C 279) and two GeV narrow-line Seyfert 1 galaxies (NLS1s, PMN J0948+0022 and 1H 0323+342) in different flux stages with one-zone leptonic models, we find a universal correlation between their Doppler factors (δ) and peak luminosities (L c) of external Compton scattering bumps. Compiling a combined sample of FSRQs and GeV NLS1s, it is found that both FSRQs and GeV NLS1s in different stages and in different sources follow the same δ-L c correlation well. This indicates that the variations of observed luminosities may be essentially due to the Doppler boosting effect. The universal δ-L c relation between FSRQs and GeV NLS1s in different stages may be further evidence that the particle acceleration and radiation mechanisms for the two kinds of sources are similar. In addition, by replacing L c with the observed luminosity in the Fermi/LAT band (L LAT), this correlation holds and it may serve as an empirical indicator of δ. We estimate the δ values with L LAT for 484 FSRQs in the Fermi/LAT Catalog and they range from 3 to 41, with a median of 16, which are statistically consistent with the values derived by other methods.

  18. GJB2 Mutation Spectrum and Genotype-Phenotype Correlation in 1067 Han Chinese Subjects with Non-Syndromic Hearing Loss.

    PubMed

    Zheng, Jing; Ying, Zhengbiao; Cai, Zhaoyang; Sun, Dongmei; He, Zheyun; Gao, Yinglong; Zhang, Ting; Zhu, Yi; Chen, Ye; Guan, Min-Xin

    2015-01-01

    Mutations in Gap Junction Beta 2 (GJB2) have been reported to be a major cause of non-syndromic hearing loss in many populations worldwide. The spectrums and frequencies of GJB2 variants vary substantially among different ethnic groups, and the genotypes among these populations remain poorly understood. In the present study, we carried out a systematic and extended mutational screening of GJB2 gene in 1067 Han Chinese subjects with non-syndromic hearing loss, and the resultant GJB2 variants were evaluated by phylogenetic, structural and bioinformatic analysis. A total of 25 (23 known and 2 novel) GJB2 variants were identified, including 6 frameshift mutations, 1 nonsense mutation, 16 missense mutations and 2 silent mutations. In this cohort, c.235delC is the most frequently observed pathogenic mutation. The phylogenetic, structural and bioinformatic analysis showed that 2 novel variants c.127G>T (p.V43L), c.293G>C (p.R98P) and 2 known variants c. 107T>C (p.L36P) and c.187G>T (p.V63L) are localized at highly conserved amino acids. In addition, these 4 mutations are absent in 203 healthy individuals, therefore, they are probably the most likely candidate pathogenic mutations. In addition, 66 (24 novel and 42 known) genotypes were identified, including 6 homozygotes, 20 compound heterozygotes, 18 single heterozygotes, 21 genotypes harboring only polymorphism(s) and the wild type genotype. Among these, 153 (14.34%) subjects were homozygous for pathogenic mutations, 63 (5.91%) were compound heterozygotes, and 157 (14.71%) carried single heterozygous mutation. Furthermore, 65.28% (141/216) of these cases with two pathogenic mutations exhibited profound hearing loss. These data suggested that mutations in GJB2 gene are responsible for approximately 34.96% of non-syndromic hearing loss in Han Chinese population from Zhejiang Province in eastern China. In addition, our results also strongly supported the idea that other factors such as alterations in regulatory regions

  19. Orthotropic Piezoelectricity in 2D Nanocellulose

    NASA Astrophysics Data System (ADS)

    García, Y.; Ruiz-Blanco, Yasser B.; Marrero-Ponce, Yovani; Sotomayor-Torres, C. M.

    2016-10-01

    The control of electromechanical responses within bonding regions is essential to face frontier challenges in nanotechnologies, such as molecular electronics and biotechnology. Here, we present Iβ-nanocellulose as a potentially new orthotropic 2D piezoelectric crystal. The predicted in-layer piezoelectricity is originated on a sui-generis hydrogen bonds pattern. Upon this fact and by using a combination of ab-initio and ad-hoc models, we introduce a description of electrical profiles along chemical bonds. Such developments lead to obtain a rationale for modelling the extended piezoelectric effect originated within bond scales. The order of magnitude estimated for the 2D Iβ-nanocellulose piezoelectric response, ~pm V‑1, ranks this material at the level of currently used piezoelectric energy generators and new artificial 2D designs. Such finding would be crucial for developing alternative materials to drive emerging nanotechnologies.

  20. Orthotropic Piezoelectricity in 2D Nanocellulose

    PubMed Central

    García, Y.; Ruiz-Blanco, Yasser B.; Marrero-Ponce, Yovani; Sotomayor-Torres, C. M.

    2016-01-01

    The control of electromechanical responses within bonding regions is essential to face frontier challenges in nanotechnologies, such as molecular electronics and biotechnology. Here, we present Iβ-nanocellulose as a potentially new orthotropic 2D piezoelectric crystal. The predicted in-layer piezoelectricity is originated on a sui-generis hydrogen bonds pattern. Upon this fact and by using a combination of ab-initio and ad-hoc models, we introduce a description of electrical profiles along chemical bonds. Such developments lead to obtain a rationale for modelling the extended piezoelectric effect originated within bond scales. The order of magnitude estimated for the 2D Iβ-nanocellulose piezoelectric response, ~pm V−1, ranks this material at the level of currently used piezoelectric energy generators and new artificial 2D designs. Such finding would be crucial for developing alternative materials to drive emerging nanotechnologies. PMID:27708364

  1. Orthotropic Piezoelectricity in 2D Nanocellulose.

    PubMed

    García, Y; Ruiz-Blanco, Yasser B; Marrero-Ponce, Yovani; Sotomayor-Torres, C M

    2016-10-06

    The control of electromechanical responses within bonding regions is essential to face frontier challenges in nanotechnologies, such as molecular electronics and biotechnology. Here, we present Iβ-nanocellulose as a potentially new orthotropic 2D piezoelectric crystal. The predicted in-layer piezoelectricity is originated on a sui-generis hydrogen bonds pattern. Upon this fact and by using a combination of ab-initio and ad-hoc models, we introduce a description of electrical profiles along chemical bonds. Such developments lead to obtain a rationale for modelling the extended piezoelectric effect originated within bond scales. The order of magnitude estimated for the 2D Iβ-nanocellulose piezoelectric response, ~pm V(-1), ranks this material at the level of currently used piezoelectric energy generators and new artificial 2D designs. Such finding would be crucial for developing alternative materials to drive emerging nanotechnologies.

  2. 2D microwave imaging reflectometer electronics

    SciTech Connect

    Spear, A. G.; Domier, C. W. Hu, X.; Muscatello, C. M.; Ren, X.; Luhmann, N. C.; Tobias, B. J.

    2014-11-15

    A 2D microwave imaging reflectometer system has been developed to visualize electron density fluctuations on the DIII-D tokamak. Simultaneously illuminated at four probe frequencies, large aperture optics image reflections from four density-dependent cutoff surfaces in the plasma over an extended region of the DIII-D plasma. Localized density fluctuations in the vicinity of the plasma cutoff surfaces modulate the plasma reflections, yielding a 2D image of electron density fluctuations. Details are presented of the receiver down conversion electronics that generate the in-phase (I) and quadrature (Q) reflectometer signals from which 2D density fluctuation data are obtained. Also presented are details on the control system and backplane used to manage the electronics as well as an introduction to the computer based control program.

  3. Large Area Synthesis of 2D Materials

    NASA Astrophysics Data System (ADS)

    Vogel, Eric

    Transition metal dichalcogenides (TMDs) have generated significant interest for numerous applications including sensors, flexible electronics, heterostructures and optoelectronics due to their interesting, thickness-dependent properties. Despite recent progress, the synthesis of high-quality and highly uniform TMDs on a large scale is still a challenge. In this talk, synthesis routes for WSe2 and MoS2 that achieve monolayer thickness uniformity across large area substrates with electrical properties equivalent to geological crystals will be described. Controlled doping of 2D semiconductors is also critically required. However, methods established for conventional semiconductors, such as ion implantation, are not easily applicable to 2D materials because of their atomically thin structure. Redox-active molecular dopants will be demonstrated which provide large changes in carrier density and workfunction through the choice of dopant, treatment time, and the solution concentration. Finally, several applications of these large-area, uniform 2D materials will be described including heterostructures, biosensors and strain sensors.

  4. 2D microwave imaging reflectometer electronics.

    PubMed

    Spear, A G; Domier, C W; Hu, X; Muscatello, C M; Ren, X; Tobias, B J; Luhmann, N C

    2014-11-01

    A 2D microwave imaging reflectometer system has been developed to visualize electron density fluctuations on the DIII-D tokamak. Simultaneously illuminated at four probe frequencies, large aperture optics image reflections from four density-dependent cutoff surfaces in the plasma over an extended region of the DIII-D plasma. Localized density fluctuations in the vicinity of the plasma cutoff surfaces modulate the plasma reflections, yielding a 2D image of electron density fluctuations. Details are presented of the receiver down conversion electronics that generate the in-phase (I) and quadrature (Q) reflectometer signals from which 2D density fluctuation data are obtained. Also presented are details on the control system and backplane used to manage the electronics as well as an introduction to the computer based control program.

  5. A scanning-mode 2D shear wave imaging (s2D-SWI) system for ultrasound elastography.

    PubMed

    Qiu, Weibao; Wang, Congzhi; Li, Yongchuan; Zhou, Juan; Yang, Ge; Xiao, Yang; Feng, Ge; Jin, Qiaofeng; Mu, Peitian; Qian, Ming; Zheng, Hairong

    2015-09-01

    Ultrasound elastography is widely used for the non-invasive measurement of tissue elasticity properties. Shear wave imaging (SWI) is a quantitative method for assessing tissue stiffness. SWI has been demonstrated to be less operator dependent than quasi-static elastography, and has the ability to acquire quantitative elasticity information in contrast with acoustic radiation force impulse (ARFI) imaging. However, traditional SWI implementations cannot acquire two dimensional (2D) quantitative images of the tissue elasticity distribution. This study proposes and evaluates a scanning-mode 2D SWI (s2D-SWI) system. The hardware and image processing algorithms are presented in detail. Programmable devices are used to support flexible control of the system and the image processing algorithms. An analytic signal based cross-correlation method and a Radon transformation based shear wave speed determination method are proposed, which can be implemented using parallel computation. Imaging of tissue mimicking phantoms, and in vitro, and in vivo imaging test are conducted to demonstrate the performance of the proposed system. The s2D-SWI system represents a new choice for the quantitative mapping of tissue elasticity, and has great potential for implementation in commercial ultrasound scanners.

  6. Neural correlates of face processing in etiologically-distinct 12-month-old infants at high-risk of autism spectrum disorder.

    PubMed

    Guy, Maggie W; Richards, John E; Tonnsen, Bridgette L; Roberts, Jane E

    2017-03-16

    Neural correlates of face processing were examined in 12-month-olds at high-risk for autism spectrum disorder (ASD), including 21 siblings of children with ASD (ASIBs) and 15 infants with fragile X syndrome (FXS), as well as 21 low-risk (LR) controls. Event-related potentials were recorded to familiar and novel face and toy stimuli. All infants demonstrated greater N290 amplitude to faces than toys. At the Nc component, LR infants showed greater amplitude to novel stimuli than to their mother's face and own toy, whereas infants with FXS showed the opposite pattern of responses and ASIBs did not differentiate based on familiarity. These results reflect developing face specialization across high- and low-risk infants and reveal neural patterns that distinguish between groups at high-risk for ASD.

  7. 2D Distributed Sensing Via TDR

    DTIC Science & Technology

    2007-11-02

    plate VEGF CompositeSensor Experimental Setup Air 279 mm 61 78 VARTM profile: slope RTM profile: rectangle 22 1 Jul 2003© 2003 University of Delaware...2003 University of Delaware All rights reserved Vision: Non-contact 2D sensing ü VARTM setup constructed within TL can be sensed by its EM field: 2D...300.0 mm/ns. 1 2 1 Jul 2003© 2003 University of Delaware All rights reserved Model Validation “ RTM Flow” TDR Response to 139 mm VEGC

  8. Inkjet printing of 2D layered materials.

    PubMed

    Li, Jiantong; Lemme, Max C; Östling, Mikael

    2014-11-10

    Inkjet printing of 2D layered materials, such as graphene and MoS2, has attracted great interests for emerging electronics. However, incompatible rheology, low concentration, severe aggregation and toxicity of solvents constitute critical challenges which hamper the manufacturing efficiency and product quality. Here, we introduce a simple and general technology concept (distillation-assisted solvent exchange) to efficiently overcome these challenges. By implementing the concept, we have demonstrated excellent jetting performance, ideal printing patterns and a variety of promising applications for inkjet printing of 2D layered materials.

  9. 2D:4D Ratio and its Implications in Medicine

    PubMed Central

    Jeevanandam, Saravanakumar

    2016-01-01

    Digit ratios, especially 2D:4D ratio, a potential proxy marker for prenatal androgen exposure shows sexual dimorphism. Existing literature and recent research show accumulating evidence on 2D:4D ratio showing correlations with various phenotypic traits in humans. Ratio of 2D:4D is found to correlate negatively to testosterone and positively to oestrogen in the foetus. Interestingly, it is constant since birth and not influenced by the adult hormone levels. Usually, males have lower ratios when compared to females. Prenatal androgen exposure and therefore, digit ratios have been reported to be associated with numerical competencies, spatial skills, handedness, cognitive abilities, academic performance, sperm counts, personalities and prevalence of obesity, migraine, eating disorders, depression, myopia, autism etc. The authors have attempted to write a brief account on the digit ratios and the dimorphism observed in various physiological, psychological and behavioural traits. Also, the authors have discussed the relevant molecular basics and the methods of measurement of digit ratios. PMID:28208851

  10. 2D IR spectra of cyanide in water investigated by molecular dynamics simulations

    USGS Publications Warehouse

    Lee, Myung Won; Carr, Joshua K.; Göllner, Michael; Hamm, Peter; Meuwly, Markus

    2013-01-01

    Using classical molecular dynamics simulations, the 2D infrared (IR) spectroscopy of CN− solvated in D2O is investigated. Depending on the force field parametrizations, most of which are based on multipolar interactions for the CN− molecule, the frequency-frequency correlation function and observables computed from it differ. Most notably, models based on multipoles for CN− and TIP3P for water yield quantitatively correct results when compared with experiments. Furthermore, the recent finding that T 1 times are sensitive to the van der Waals ranges on the CN− is confirmed in the present study. For the linear IR spectrum, the best model reproduces the full widths at half maximum almost quantitatively (13.0 cm−1 vs. 14.9 cm−1) if the rotational contribution to the linewidth is included. Without the rotational contribution, the lines are too narrow by about a factor of two, which agrees with Raman and IR experiments. The computed and experimental tilt angles (or nodal slopes) α as a function of the 2D IR waiting time compare favorably with the measured ones and the frequency fluctuation correlation function is invariably found to contain three time scales: a sub-ps, 1 ps, and one on the 10-ps time scale. These time scales are discussed in terms of the structural dynamics of the surrounding solvent and it is found that the longest time scale (≈10 ps) most likely corresponds to solvent exchange between the first and second solvation shell, in agreement with interpretations from nuclear magnetic resonance measurements.

  11. 2D properties of core turbulence on DIII-D and comparison to gyrokinetic simulations

    SciTech Connect

    Shafer, Morgan W; Fonck, R. J.; McKee, G. R.; Holland, Chris; White, A. E.; Schlossberg, D J

    2012-01-01

    Quantitative 2D characteristics of localized density fluctuations are presented over the range of 0.3 < r/a < 0.9 in L-mode plasmas on DIII-D [J. L. Luxon, Nucl. Fusion 42, 614 (2002)]. Broadband density fluctuations increase in amplitude from (n) over tilde/n < 0.5% in the deep core to (n) over tilde/n similar to 2.5% near the outer region. The observed Doppler-shift due to the E x B velocity matches well with the measured turbulence group and phase velocities (in toroidally rotating neutral beam heated plasmas). Turbulence decorrelation rates are found to be similar to 200 kHz at the edge and to decrease toward the core (0.45 < r/a < 0.9) where they approach the E x B shearing rate (similar to 50 kHz). Radial and poloidal correlation lengths are found to scale with the ion gyroradius and exhibit an asymmetric poloidally elongated eddy structure. The ensemble-averaged turbulent eddy structure changes its tilt with respect to the radial-poloidal coordinates in the core, consistent with an E x B shear mechanism. The 2D spatial correlation and wavenumber spectra [S(k(r); k(theta))] are presented and compared to nonlinear flux-tube GYRO simulations at two radii, r/a = 0.5 and r/a = 0.75, showing reasonable overall agreement, but the GYRO spectrum exhibits a peak at finite kr for r/a = 0.75 that is not observed experimentally; E x B shear may cause this discrepancy. (C) 2012 American Institute of Physics.

  12. Omega-3 and Omega-6 Polyunsaturated Fatty Acid Levels and Correlations with Symptoms in Children with Attention Deficit Hyperactivity Disorder, Autistic Spectrum Disorder and Typically Developing Controls

    PubMed Central

    Niyonsenga, Theophile; Duff, Jacques

    2016-01-01

    Background There is evidence that children with Attention Deficit Hyperactivity Disorder (ADHD) and Autistic Spectrum Disorder (ASD) have lower omega-3 polyunsaturated fatty acid (n-3 PUFA) levels compared with controls and conflicting evidence regarding omega-6 (n-6) PUFA levels. Objectives This study investigated whether erythrocyte n-3 PUFAs eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were lower and n-6 PUFA arachidonic acid (AA) higher in children with ADHD, ASD and controls, and whether lower n-3 and higher n-6 PUFAs correlated with poorer scores on the Australian Twin Behaviour Rating Scale (ATBRS; ADHD symptoms) and Test of Variable Attention (TOVA) in children with ADHD, and Childhood Autism Rating Scale (CARS) in children with ASD. Methods Assessments and blood samples of 565 children aged 3–17 years with ADHD (n = 401), ASD (n = 85) or controls (n = 79) were analysed. One-way ANOVAs with Tukey’s post-hoc analysis investigated differences in PUFA levels between groups and Pearson’s correlations investigated correlations between PUFA levels and ATBRS, TOVA and CARS scores. Results Children with ADHD and ASD had lower DHA, EPA and AA, higher AA/EPA ratio and lower n-3/n-6 than controls (P<0.001 except AA between ADHD and controls: P = 0.047). Children with ASD had lower DHA, EPA and AA than children with ADHD (P<0.001 for all comparisons). ATBRS scores correlated negatively with EPA (r = -.294, P<0.001), DHA (r = -.424, P<0.001), n-3/n-6 (r = -.477, P<0.001) and positively with AA/EPA (r = .222, P <.01). TOVA scores correlated positively with DHA (r = .610, P<0.001), EPA (r = .418, P<0.001) AA (r = .199, P<0.001), and n-3/n-6 (r = .509, P<0.001) and negatively with AA/EPA (r = -.243, P<0.001). CARS scores correlated significantly with DHA (r = .328, P = 0.002), EPA (r = -.225, P = 0.038) and AA (r = .251, P = 0.021). Conclusions Children with ADHD and ASD had low levels of EPA, DHA and AA and high ratio of n-6/n-3 PUFAs and these

  13. Structural Complexity and Phonon Physics in 2D Arsenenes.

    PubMed

    Carrete, Jesús; Gallego, Luis J; Mingo, Natalio

    2017-03-15

    In the quest for stable 2D arsenic phases, four different structures have been recently claimed to be stable. We show that, due to phonon contributions, the relative stability of those structures differs from previous reports and depends crucially on temperature. We also show that one of those four phases is in fact mechanically unstable. Furthermore, our results challenge the common assumption of an inverse correlation between structural complexity and thermal conductivity. Instead, a richer picture emerges from our results, showing how harmonic interactions, anharmonicity, and symmetries all play a role in modulating thermal conduction in arsenenes. More generally, our conclusions highlight how vibrational properties are an essential element to be carefully taken into account in theoretical searches for new 2D materials.

  14. Spectrum of FOXL2 gene mutations in blepharophimosis-ptosis-epicanthus inversus (BPES) families demonstrates a genotype--phenotype correlation.

    PubMed

    De Baere, E; Dixon, M J; Small, K W; Jabs, E W; Leroy, B P; Devriendt, K; Gillerot, Y; Mortier, G; Meire, F; Van Maldergem, L; Courtens, W; Hjalgrim, H; Huang, S; Liebaers, I; Van Regemorter, N; Touraine, P; Praphanphoj, V; Verloes, A; Udar, N; Yellore, V; Chalukya, M; Yelchits, S; De Paepe, A; Kuttenn, F; Fellous, M; Veitia, R; Messiaen, L

    2001-07-15

    Mutations in FOXL2, a forkhead transcription factor gene, have recently been shown to cause blepharophimosis-ptosis-epicanthus inversus syndrome (BPES) types I and II, a rare genetic disorder. In BPES type I a complex eyelid malformation is associated with premature ovarian failure (POF), whereas in BPES type II the eyelid defect occurs as an isolated entity. In this study, we describe the identification of novel mutations in the FOXL2 gene in BPES types I and II families, in sporadic BPES patients, and in BPES families where the type could not be established. In 67% of the patients studied, we identified a mutation in the FOXL2 gene. In total, 21 mutations (17 of which are novel) and one microdeletion were identified. Thirteen of these FOXL2 mutations are unique. In this study, we demonstrate that there is a genotype--phenotype correlation for either types of BPES by the finding that mutations predicted to result in a truncated protein either lacking or containing the forkhead domain lead to BPES type I. In contrast, duplications within or downstream of the forkhead domain, and a frameshift downstream of them, all predicted to result in an extended protein, cause BPES type II. In addition, in 30 unrelated patients with isolated POF no causal mutations were identified in FOXL2. Our study provides further evidence that FOXL2 haploinsufficiency may cause BPES types I and II by the effect of a null allele and a hypomorphic allele, respectively. Furthermore, we propose that in a fraction of the BPES patients the genetic defect does not reside within the coding region of the FOXL2 gene and may be caused by a position effect.

  15. The clinical spectrum of renal osteodystrophy in 57 chronic hemodialysis patients: a correlation between biochemical parameters and bone pathology findings.

    PubMed

    Chazan, J A; Libbey, N P; London, M R; Pono, L; Abuelo, J G

    1991-02-01

    Fifty-nine chronic hemodialysis patients who had been on dialysis for an average of 77 months underwent bone biopsies and the pathologic findings were correlated with biochemical and demographic data. All but two had evidence of renal osteodystrophy, 23 with osteitis fibrosa (OF), 19 with osteomalacia and/or adynamic disease (OM/AD), and 15 with mixed osteodystrophy (MOD). Patients in each group were similar with regard to age, sex distribution, duration of dialysis, unstimulated serum aluminum, calcium and phosphorus. Patients with osteitis fibrosa (OF) had statistically higher DFO stimulated aluminum, alkaline phosphatase and PTHC levels than the other two groups although there was marked individual variation. The bone biopsies were also evaluated for the amount of aluminum deposited in the osteoid seam. All 23 of the patients with OF and 11 of the 15 patients with MOD had no, mild, or minimal aluminum deposition but 12 of the 19 patients with OM/AD had moderate to marked aluminum deposition. Patients with minimal to mild aluminum deposition were similar in age, duration of dialysis, sex distribution, unstimulated and DFO stimulated aluminum levels, calcium, phosphorus, alkaline phosphatase to those with moderate to marked deposition but had significantly higher parathormone levels. All patients had been treated in a similar fashion regarding diet, oral phosphate binders and vitamin D; therefore, the observed differences in bone pathology were not readily explicable. However, patients who were found to have osteitis fibrosa and those with minimal to mild aluminum deposition had significantly higher parathormone levels when compared with patients in the other groups at the inception of dialysis.

  16. Genotype-phenotype correlation in a cohort of Portuguese patients comprising the entire spectrum of VWD types: impact of NGS.

    PubMed

    Fidalgo, Teresa; Salvado, Ramon; Corrales, Irene; Pinto, Silva Catarina; Borràs, Nina; Oliveira, Ana; Martinho, Patricia; Ferreira, Gisela; Almeida, Helena; Oliveira, Cristina; Marques, Dalila; Gonçalves, Elsa; Diniz, MJoão; Antunes, Margarida; Tavares, Alice; Caetano, Gonçalo; Kjöllerström, Paula; Maia, Raquel; Sevivas, Teresa S; Vidal, Francisco; Ribeiro, Leticia

    2016-07-04

    The diagnosis of von Willebrand disease (VWD), the most common inherited bleeding disorder, is characterised by a variable bleeding tendency and heterogeneous laboratory phenotype. The sequencing of the entire VWF coding region has not yet become a routine practice in diagnostic laboratories owing to its high costs. Nevertheless, next-generation sequencing (NGS) has emerged as an alternative to overcome this limitation. We aimed to determine the correlation of genotype and phenotype in 92 Portuguese individuals from 60 unrelated families with VWD; therefore, we directly sequenced VWF. We compared the classical Sanger sequencing approach and NGS to assess the value-added effect on the analysis of the mutation distribution in different types of VWD. Sixty-two different VWF mutations were identified, 27 of which had not been previously described. NGS detected 26 additional mutations, contributing to a broad overview of the mutant alleles present in each VWD type. Twenty-nine probands (48.3 %) had two or more mutations; in addition, mutations with pleiotropic effects were detected, and NGS allowed an appropriate classification for seven of them. Furthermore, the differential diagnosis between VWD 2B and platelet type VWD (n = 1), Bernard-Soulier syndrome and VWD 2B (n = 1), and mild haemophilia A and VWD 2N (n = 2) was possible. NGS provided an efficient laboratory workflow for analysing VWF. These findings in our cohort of Portuguese patients support the proposal that improving VWD diagnosis strategies will enhance clinical and laboratory approaches, allowing to establish the most appropriate treatment for each patient.

  17. The Relationship Between Digit Ratio (2D:4D) and Sexual Orientation in Men from China.

    PubMed

    Xu, Yin; Zheng, Yong

    2016-04-01

    We examined the relationship between 2D:4D digit ratio and sexual orientation in men from China and analyzed the influences of the components used to assess sexual orientation and the criteria used to classify individuals as homosexual on this relationship. A total of 309 male and 110 female participants took part in a web-based survey. Our results showed that heterosexual men had a significantly lower 2D:4D than heterosexual women and exclusively homosexual men had a significantly higher left 2D:4D than heterosexual men whereas only exclusively homosexual men had a significantly higher right 2D:4D than heterosexual men when sexual orientation was assessed via sexual attraction. The left 2D:4D showed a significant positive correlation with sexual identity, sexual attraction, and sexual behavior, and the right 2D:4D showed a significant positive correlation with sexual attraction. The effect sizes for differences in 2D:4D between homosexual and heterosexual men varied according to criteria used to classify individuals as homosexual and sexual orientation components; the more stringent the criteria (scores closer to the homosexual category), the larger the effect sizes; further, sexual attraction yielded the largest effect size. There were no significant effects of age and latitude on Chinese 2D:4D. This study contributes to the current understanding of the relationship between 2D:4D and male sexual orientation.

  18. Parallel Stitching of 2D Materials.

    PubMed

    Ling, Xi; Lin, Yuxuan; Ma, Qiong; Wang, Ziqiang; Song, Yi; Yu, Lili; Huang, Shengxi; Fang, Wenjing; Zhang, Xu; Hsu, Allen L; Bie, Yaqing; Lee, Yi-Hsien; Zhu, Yimei; Wu, Lijun; Li, Ju; Jarillo-Herrero, Pablo; Dresselhaus, Mildred; Palacios, Tomás; Kong, Jing

    2016-03-23

    Diverse parallel stitched 2D heterostructures, including metal-semiconductor, semiconductor-semiconductor, and insulator-semiconductor, are synthesized directly through selective "sowing" of aromatic molecules as the seeds in the chemical vapor deposition (CVD) method. The methodology enables the large-scale fabrication of lateral heterostructures, which offers tremendous potential for its application in integrated circuits.

  19. The basics of 2D DIGE.

    PubMed

    Beckett, Phil

    2012-01-01

    The technique of two-dimensional (2D) gel electrophoresis is a powerful tool for separating complex mixtures of proteins, but since its inception in the mid 1970s, it acquired the stigma of being a very difficult application to master and was generally used to its best effect by experts. The introduction of commercially available immobilized pH gradients in the early 1990s provided enhanced reproducibility and easier protocols, leading to a pronounced increase in popularity of the technique. However gel-to-gel variation was still difficult to control without the use of technical replicates. In the mid 1990s (at the same time as the birth of "proteomics"), the concept of multiplexing fluorescently labeled proteins for 2D gel separation was realized by Jon Minden's group and has led to the ability to design experiments to virtually eliminate gel-to-gel variation, resulting in biological replicates being used for statistical analysis with the ability to detect very small changes in relative protein abundance. This technology is referred to as 2D difference gel electrophoresis (2D DIGE).

  20. Parallel stitching of 2D materials

    DOE PAGES

    Ling, Xi; Wu, Lijun; Lin, Yuxuan; ...

    2016-01-27

    Diverse parallel stitched 2D heterostructures, including metal–semiconductor, semiconductor–semiconductor, and insulator–semiconductor, are synthesized directly through selective “sowing” of aromatic molecules as the seeds in the chemical vapor deposition (CVD) method. Lastly, the methodology enables the large-scale fabrication of lateral heterostructures, which offers tremendous potential for its application in integrated circuits.

  1. Acousto-Optic Processing of 2-D Signals Using Temporal and Spatial Integration.

    DTIC Science & Technology

    1983-05-31

    Documents includes data on: Architectures; Coherence Properties of Pulsed Laser Diodes; Acousto - optic device data; Dynamic Range Issues; Image correlation; Synthetic aperture radar; 2-D Fourier transform; and Moments.

  2. 2D resistivity method in delineating subsurface problems in urban area

    NASA Astrophysics Data System (ADS)

    Nordiana, M. M.; Saad, Rosli; Teh Saufia, A. H. A.; Azwin, I. N.; Ali, Nisa'; Hidayah, Noer El

    2013-05-01

    2D resistivity is carried out to detect spread saturated zone and subsurface problems cause by the presence of underground river, which resulted from selected urban area at Selangor, Malaysia. Six 2D resistivity survey lines with minimum 5 m electrode spacing were executed using Pole-dipole array. Borehole was carried out at multiple locations in the study area. Subsequently, the borehole was used to verify the 2D resistivity results. Interpretation of 2D resistivity data showed a low resistivity value (< 40 ohm-m), which appears to be a zone that is fully saturated with sandy silt and this could be an influence factor the increasing water level because sandy silt is highly permeable in nature. The borehole, support the results of 2D resistivity method relating a saturated zone in the survey area. There is a good correlation between the 2D resistivity investigations and the results of borehole records.

  3. Investigation of the nitrogen hyperfine coupling of the second stable radical in γ-irradiated L-alanine crystals by 2D-HYSCORE spectroscopy

    NASA Astrophysics Data System (ADS)

    Maltar-Strmečki, Nadica; Rakvin, Boris

    2012-09-01

    The second stable radical, NH3+C(CH3)COO, R2, in the γ-irradiated single crystal of L-alanine and its fully 15N-enriched analogue were studied by an advanced pulsed EPR technique, 2D-HYSCORE (two-dimensional hyperfine sublevel correlation) spectroscopy at 200 K. The nitrogen hyperfine coupling tensor of the R2 radical was determined from the HYSCORE data and provides new experimental data for improved characterization of the R2 radical in the crystal lattice. The results obtained complement the experimental proton data available for the R2 radical and could lead to increased accuracy and reliability of EPR spectrum simulations.

  4. Application of 2D Non-Graphene Materials and 2D Oxide Nanostructures for Biosensing Technology

    PubMed Central

    Shavanova, Kateryna; Bakakina, Yulia; Burkova, Inna; Shtepliuk, Ivan; Viter, Roman; Ubelis, Arnolds; Beni, Valerio; Starodub, Nickolaj; Yakimova, Rositsa; Khranovskyy, Volodymyr

    2016-01-01

    The discovery of graphene and its unique properties has inspired researchers to try to invent other two-dimensional (2D) materials. After considerable research effort, a distinct “beyond graphene” domain has been established, comprising the library of non-graphene 2D materials. It is significant that some 2D non-graphene materials possess solid advantages over their predecessor, such as having a direct band gap, and therefore are highly promising for a number of applications. These applications are not limited to nano- and opto-electronics, but have a strong potential in biosensing technologies, as one example. However, since most of the 2D non-graphene materials have been newly discovered, most of the research efforts are concentrated on material synthesis and the investigation of the properties of the material. Applications of 2D non-graphene materials are still at the embryonic stage, and the integration of 2D non-graphene materials into devices is scarcely reported. However, in recent years, numerous reports have blossomed about 2D material-based biosensors, evidencing the growing potential of 2D non-graphene materials for biosensing applications. This review highlights the recent progress in research on the potential of using 2D non-graphene materials and similar oxide nanostructures for different types of biosensors (optical and electrochemical). A wide range of biological targets, such as glucose, dopamine, cortisol, DNA, IgG, bisphenol, ascorbic acid, cytochrome and estradiol, has been reported to be successfully detected by biosensors with transducers made of 2D non-graphene materials. PMID:26861346

  5. Application of 2D Non-Graphene Materials and 2D Oxide Nanostructures for Biosensing Technology.

    PubMed

    Shavanova, Kateryna; Bakakina, Yulia; Burkova, Inna; Shtepliuk, Ivan; Viter, Roman; Ubelis, Arnolds; Beni, Valerio; Starodub, Nickolaj; Yakimova, Rositsa; Khranovskyy, Volodymyr

    2016-02-06

    The discovery of graphene and its unique properties has inspired researchers to try to invent other two-dimensional (2D) materials. After considerable research effort, a distinct "beyond graphene" domain has been established, comprising the library of non-graphene 2D materials. It is significant that some 2D non-graphene materials possess solid advantages over their predecessor, such as having a direct band gap, and therefore are highly promising for a number of applications. These applications are not limited to nano- and opto-electronics, but have a strong potential in biosensing technologies, as one example. However, since most of the 2D non-graphene materials have been newly discovered, most of the research efforts are concentrated on material synthesis and the investigation of the properties of the material. Applications of 2D non-graphene materials are still at the embryonic stage, and the integration of 2D non-graphene materials into devices is scarcely reported. However, in recent years, numerous reports have blossomed about 2D material-based biosensors, evidencing the growing potential of 2D non-graphene materials for biosensing applications. This review highlights the recent progress in research on the potential of using 2D non-graphene materials and similar oxide nanostructures for different types of biosensors (optical and electrochemical). A wide range of biological targets, such as glucose, dopamine, cortisol, DNA, IgG, bisphenol, ascorbic acid, cytochrome and estradiol, has been reported to be successfully detected by biosensors with transducers made of 2D non-graphene materials.

  6. Fast, accurate 2D-MR relaxation exchange spectroscopy (REXSY): Beyond compressed sensing

    NASA Astrophysics Data System (ADS)

    Bai, Ruiliang; Benjamini, Dan; Cheng, Jian; Basser, Peter J.

    2016-10-01

    Previously, we showed that compressive or compressed sensing (CS) can be used to reduce significantly the data required to obtain 2D-NMR relaxation and diffusion spectra when they are sparse or well localized. In some cases, an order of magnitude fewer uniformly sampled data were required to reconstruct 2D-MR spectra of comparable quality. Nonetheless, this acceleration may still not be sufficient to make 2D-MR spectroscopy practicable for many important applications, such as studying time-varying exchange processes in swelling gels or drying paints, in living tissue in response to various biological or biochemical challenges, and particularly for in vivo MRI applications. A recently introduced framework, marginal distributions constrained optimization (MADCO), tremendously accelerates such 2D acquisitions by using a priori obtained 1D marginal distribution as powerful constraints when 2D spectra are reconstructed. Here we exploit one important intrinsic property of the 2D-MR relaxation exchange spectra: the fact that the 1D marginal distributions of each 2D-MR relaxation exchange spectrum in both dimensions are equal and can be rapidly estimated from a single Carr-Purcell-Meiboom-Gill (CPMG) or inversion recovery prepared CPMG measurement. We extend the MADCO framework by further proposing to use the 1D marginal distributions to inform the subsequent 2D data-sampling scheme, concentrating measurements where spectral peaks are present and reducing them where they are not. In this way we achieve compression or acceleration that is an order of magnitude greater than that in our previous CS method while providing data in reconstructed 2D-MR spectral maps of comparable quality, demonstrated using several simulated and real 2D T2 - T2 experimental data. This method, which can be called "informed compressed sensing," is extendable to other 2D- and even ND-MR exchange spectroscopy.

  7. Compatible embedding for 2D shape animation.

    PubMed

    Baxter, William V; Barla, Pascal; Anjyo, Ken-Ichi

    2009-01-01

    We present new algorithms for the compatible embedding of 2D shapes. Such embeddings offer a convenient way to interpolate shapes having complex, detailed features. Compared to existing techniques, our approach requires less user input, and is faster, more robust, and simpler to implement, making it ideal for interactive use in practical applications. Our new approach consists of three parts. First, our boundary matching algorithm locates salient features using the perceptually motivated principles of scale-space and uses these as automatic correspondences to guide an elastic curve matching algorithm. Second, we simplify boundaries while maintaining their parametric correspondence and the embedding of the original shapes. Finally, we extend the mapping to shapes' interiors via a new compatible triangulation algorithm. The combination of our algorithms allows us to demonstrate 2D shape interpolation with instant feedback. The proposed algorithms exhibit a combination of simplicity, speed, and accuracy that has not been achieved in previous work.

  8. Schottky diodes from 2D germanane

    NASA Astrophysics Data System (ADS)

    Sahoo, Nanda Gopal; Esteves, Richard J.; Punetha, Vinay Deep; Pestov, Dmitry; Arachchige, Indika U.; McLeskey, James T.

    2016-07-01

    We report on the fabrication and characterization of a Schottky diode made using 2D germanane (hydrogenated germanene). When compared to germanium, the 2D structure has higher electron mobility, an optimal band-gap, and exceptional stability making germanane an outstanding candidate for a variety of opto-electronic devices. One-atom-thick sheets of hydrogenated puckered germanium atoms have been synthesized from a CaGe2 framework via intercalation and characterized by XRD, Raman, and FTIR techniques. The material was then used to fabricate Schottky diodes by suspending the germanane in benzonitrile and drop-casting it onto interdigitated metal electrodes. The devices demonstrate significant rectifying behavior and the outstanding potential of this material.

  9. Extrinsic Cation Selectivity of 2D Membranes

    PubMed Central

    2017-01-01

    From a systematic study of the concentration driven diffusion of positive and negative ions across porous 2D membranes of graphene and hexagonal boron nitride (h-BN), we prove their cation selectivity. Using the current–voltage characteristics of graphene and h-BN monolayers separating reservoirs of different salt concentrations, we calculate the reversal potential as a measure of selectivity. We tune the Debye screening length by exchanging the salt concentrations and demonstrate that negative surface charge gives rise to cation selectivity. Surprisingly, h-BN and graphene membranes show similar characteristics, strongly suggesting a common origin of selectivity in aqueous solvents. For the first time, we demonstrate that the cation flux can be increased by using ozone to create additional pores in graphene while maintaining excellent selectivity. We discuss opportunities to exploit our scalable method to use 2D membranes for applications including osmotic power conversion. PMID:28157333

  10. Static & Dynamic Response of 2D Solids

    SciTech Connect

    Lin, Jerry

    1996-07-15

    NIKE2D is an implicit finite-element code for analyzing the finite deformation, static and dynamic response of two-dimensional, axisymmetric, plane strain, and plane stress solids. The code is fully vectorized and available on several computing platforms. A number of material models are incorporated to simulate a wide range of material behavior including elasto-placicity, anisotropy, creep, thermal effects, and rate dependence. Slideline algorithms model gaps and sliding along material interfaces, including interface friction, penetration and single surface contact. Interactive-graphics and rezoning is included for analyses with large mesh distortions. In addition to quasi-Newton and arc-length procedures, adaptive algorithms can be defined to solve the implicit equations using the solution language ISLAND. Each of these capabilities and more make NIKE2D a robust analysis tool.

  11. Explicit 2-D Hydrodynamic FEM Program

    SciTech Connect

    Lin, Jerry

    1996-08-07

    DYNA2D* is a vectorized, explicit, two-dimensional, axisymmetric and plane strain finite element program for analyzing the large deformation dynamic and hydrodynamic response of inelastic solids. DYNA2D* contains 13 material models and 9 equations of state (EOS) to cover a wide range of material behavior. The material models implemented in all machine versions are: elastic, orthotropic elastic, kinematic/isotropic elastic plasticity, thermoelastoplastic, soil and crushable foam, linear viscoelastic, rubber, high explosive burn, isotropic elastic-plastic, temperature-dependent elastic-plastic. The isotropic and temperature-dependent elastic-plastic models determine only the deviatoric stresses. Pressure is determined by one of 9 equations of state including linear polynomial, JWL high explosive, Sack Tuesday high explosive, Gruneisen, ratio of polynomials, linear polynomial with energy deposition, ignition and growth of reaction in HE, tabulated compaction, and tabulated.

  12. Quasiparticle interference in unconventional 2D systems

    NASA Astrophysics Data System (ADS)

    Chen, Lan; Cheng, Peng; Wu, Kehui

    2017-03-01

    At present, research of 2D systems mainly focuses on two kinds of materials: graphene-like materials and transition-metal dichalcogenides (TMDs). Both of them host unconventional 2D electronic properties: pseudospin and the associated chirality of electrons in graphene-like materials, and spin-valley-coupled electronic structures in the TMDs. These exotic electronic properties have attracted tremendous interest for possible applications in nanodevices in the future. Investigation on the quasiparticle interference (QPI) in 2D systems is an effective way to uncover these properties. In this review, we will begin with a brief introduction to 2D systems, including their atomic structures and electronic bands. Then, we will discuss the formation of Friedel oscillation due to QPI in constant energy contours of electron bands, and show the basic concept of Fourier-transform scanning tunneling microscopy/spectroscopy (FT-STM/STS), which can resolve Friedel oscillation patterns in real space and consequently obtain the QPI patterns in reciprocal space. In the next two parts, we will summarize some pivotal results in the investigation of QPI in graphene and silicene, in which systems the low-energy quasiparticles are described by the massless Dirac equation. The FT-STM experiments show there are two different interference channels (intervalley and intravalley scattering) and backscattering suppression, which associate with the Dirac cones and the chirality of quasiparticles. The monolayer and bilayer graphene on different substrates (SiC and metal surfaces), and the monolayer and multilayer silicene on a Ag(1 1 1) surface will be addressed. The fifth part will introduce the FT-STM research on QPI in TMDs (monolayer and bilayer of WSe2), which allow us to infer the spin texture of both conduction and valence bands, and present spin-valley coupling by tracking allowed and forbidden scattering channels.

  13. Compact 2-D graphical representation of DNA

    NASA Astrophysics Data System (ADS)

    Randić, Milan; Vračko, Marjan; Zupan, Jure; Novič, Marjana

    2003-05-01

    We present a novel 2-D graphical representation for DNA sequences which has an important advantage over the existing graphical representations of DNA in being very compact. It is based on: (1) use of binary labels for the four nucleic acid bases, and (2) use of the 'worm' curve as template on which binary codes are placed. The approach is illustrated on DNA sequences of the first exon of human β-globin and gorilla β-globin.

  14. 2D Metals by Repeated Size Reduction.

    PubMed

    Liu, Hanwen; Tang, Hao; Fang, Minghao; Si, Wenjie; Zhang, Qinghua; Huang, Zhaohui; Gu, Lin; Pan, Wei; Yao, Jie; Nan, Cewen; Wu, Hui

    2016-10-01

    A general and convenient strategy for manufacturing freestanding metal nanolayers is developed on large scale. By the simple process of repeatedly folding and calendering stacked metal sheets followed by chemical etching, free-standing 2D metal (e.g., Ag, Au, Fe, Cu, and Ni) nanosheets are obtained with thicknesses as small as 1 nm and with sizes of the order of several micrometers.

  15. Realistic and efficient 2D crack simulation

    NASA Astrophysics Data System (ADS)

    Yadegar, Jacob; Liu, Xiaoqing; Singh, Abhishek

    2010-04-01

    Although numerical algorithms for 2D crack simulation have been studied in Modeling and Simulation (M&S) and computer graphics for decades, realism and computational efficiency are still major challenges. In this paper, we introduce a high-fidelity, scalable, adaptive and efficient/runtime 2D crack/fracture simulation system by applying the mathematically elegant Peano-Cesaro triangular meshing/remeshing technique to model the generation of shards/fragments. The recursive fractal sweep associated with the Peano-Cesaro triangulation provides efficient local multi-resolution refinement to any level-of-detail. The generated binary decomposition tree also provides efficient neighbor retrieval mechanism used for mesh element splitting and merging with minimal memory requirements essential for realistic 2D fragment formation. Upon load impact/contact/penetration, a number of factors including impact angle, impact energy, and material properties are all taken into account to produce the criteria of crack initialization, propagation, and termination leading to realistic fractal-like rubble/fragments formation. The aforementioned parameters are used as variables of probabilistic models of cracks/shards formation, making the proposed solution highly adaptive by allowing machine learning mechanisms learn the optimal values for the variables/parameters based on prior benchmark data generated by off-line physics based simulation solutions that produce accurate fractures/shards though at highly non-real time paste. Crack/fracture simulation has been conducted on various load impacts with different initial locations at various impulse scales. The simulation results demonstrate that the proposed system has the capability to realistically and efficiently simulate 2D crack phenomena (such as window shattering and shards generation) with diverse potentials in military and civil M&S applications such as training and mission planning.

  16. Volumetric elasticity imaging with a 2-D CMUT array.

    PubMed

    Fisher, Ted G; Hall, Timothy J; Panda, Satchi; Richards, Michael S; Barbone, Paul E; Jiang, Jingfeng; Resnick, Jeff; Barnes, Steve

    2010-06-01

    This article reports the use of a two-dimensional (2-D) capacitive micro-machined ultrasound transducer (CMUT) to acquire radio-frequency (RF) echo data from relatively large volumes of a simple ultrasound phantom to compare three-dimensional (3-D) elasticity imaging methods. Typical 2-D motion tracking for elasticity image formation was compared with three different methods of 3-D motion tracking, with sum-squared difference (SSD) used as the similarity measure. Differences among the algorithms were the degree to which they tracked elevational motion: not at all (2-D search), planar search, combination of multiple planes and plane independent guided search. The cross-correlation between the predeformation and motion-compensated postdeformation RF echo fields was used to quantify motion tracking accuracy. The lesion contrast-to-noise ratio was used to quantify image quality. Tracking accuracy and strain image quality generally improved with increased tracking sophistication. When used as input for a 3-D modulus reconstruction, high quality 3-D displacement estimates yielded accurate and low noise modulus reconstruction.

  17. Volumetric Elasticity Imaging with a 2D CMUT Array

    PubMed Central

    Fisher, Ted G.; Hall, Timothy J.; Panda, Satchi; Richards, Michael S.; Barbone, Paul E.; Jiang, Jingfeng; Resnick, Jeff; Barnes, Steve

    2010-01-01

    This paper reports the use of a two-dimensional (2D) capacitive micro-machined ultrasound transducer (CMUT) to acquire radio frequency (RF) echo data from relatively large volumes of a simple ultrasound phantom to compare 3D elasticity imaging methods. Typical 2D motion tracking for elasticity image formation was compared to three different methods of 3D motion tracking, with sum-squared difference (SSD) used as the similarity measure. Differences among the algorithms were the degree to which they tracked elevational motion: not at all (2D search), planar search, combination of multiple planes, and plane independent guided search. The cross correlation between the pre-deformation and motion-compensated post-deformation RF echo fields was used to quantify motion tracking accuracy. The lesion contrast-to-noise ratio was used to quantify image quality. Tracking accuracy and strain image quality generally improved with increased tracking sophistication. When used as input for a 3D modulus reconstruction, high quality 3D displacement estimates yielded accurate and low noise modulus reconstruction. PMID:20510188

  18. Engineering light outcoupling in 2D materials.

    PubMed

    Lien, Der-Hsien; Kang, Jeong Seuk; Amani, Matin; Chen, Kevin; Tosun, Mahmut; Wang, Hsin-Ping; Roy, Tania; Eggleston, Michael S; Wu, Ming C; Dubey, Madan; Lee, Si-Chen; He, Jr-Hau; Javey, Ali

    2015-02-11

    When light is incident on 2D transition metal dichalcogenides (TMDCs), it engages in multiple reflections within underlying substrates, producing interferences that lead to enhancement or attenuation of the incoming and outgoing strength of light. Here, we report a simple method to engineer the light outcoupling in semiconducting TMDCs by modulating their dielectric surroundings. We show that by modulating the thicknesses of underlying substrates and capping layers, the interference caused by substrate can significantly enhance the light absorption and emission of WSe2, resulting in a ∼11 times increase in Raman signal and a ∼30 times increase in the photoluminescence (PL) intensity of WSe2. On the basis of the interference model, we also propose a strategy to control the photonic and optoelectronic properties of thin-layer WSe2. This work demonstrates the utilization of outcoupling engineering in 2D materials and offers a new route toward the realization of novel optoelectronic devices, such as 2D LEDs and solar cells.

  19. Irreversibility-inversions in 2D turbulence

    NASA Astrophysics Data System (ADS)

    Bragg, Andrew; de Lillo, Filippo; Boffetta, Guido

    2016-11-01

    We consider a recent theoretical prediction that for inertial particles in 2D turbulence, the nature of the irreversibility of their pair dispersion inverts when the particle inertia exceeds a certain value. In particular, when the particle Stokes number, St , is below a certain value, the forward-in-time (FIT) dispersion should be faster than the backward-in-time (BIT) dispersion, but for St above this value, this should invert so that BIT becomes faster than FIT dispersion. This non-trivial behavior arises because of the competition between two physically distinct irreversibility mechanisms that operate in different regimes of St . In 3D turbulence, both mechanisms act to produce faster BIT than FIT dispersion, but in 2D, the two mechanisms have opposite effects because of the inverse energy cascade in the turbulent velocity field. We supplement the qualitative argument given by Bragg et al. by deriving quantitative predictions of this effect in the short-time dispersion limit. These predictions are then confirmed by results of inertial particle dispersion in a direct numerical simulation of 2D turbulence.

  20. Numerical modelling of spallation in 2D hydrodynamics codes

    NASA Astrophysics Data System (ADS)

    Maw, J. R.; Giles, A. R.

    1996-05-01

    A model for spallation based on the void growth model of Johnson has been implemented in 2D Lagrangian and Eulerian hydrocodes. The model has been extended to treat complete separation of material when voids coalesce and to describe the effects of elevated temperatures and melting. The capabilities of the model are illustrated by comparison with data from explosively generated spall experiments. Particular emphasis is placed on the prediction of multiple spall effects in weak, low melting point, materials such as lead. The correlation between the model predictions and observations on the strain rate dependence of spall strength is discussed.

  1. Modified two-dimensional correlation spectra for streamlined determination of sequential order of intensity variations

    NASA Astrophysics Data System (ADS)

    Noda, Isao

    2016-11-01

    Modified forms of two-dimensional (2D) correlation spectra, i.e., sign-adjusted asynchronous spectrum and merged correlation spectrum, are discussed. They are developed for the streamlined determination of the sequential order of spectral intensity variations using only one 2D map by combining the pertinent information of synchronous and asynchronous spectra. Development of small side lobe artifacts near the peripheral of a cross peak is sometimes noted, especially for highly overlapped bands which are changing intensities in the opposite directions. The merit of the ease of interpretation afforded by the modification of correlation spectra probably outweighs the introduction minor artifacts, but some care certainly is required to avoid misinterpretation. Modified spectrum provides additional characteristic signature to the butterfly pattern cluster of cross peaks for the unambiguous identification of the presence of a band with position shift.

  2. 2D superconductivity by ionic gating

    NASA Astrophysics Data System (ADS)

    Iwasa, Yoshi

    2D superconductivity is attracting a renewed interest due to the discoveries of new highly crystalline 2D superconductors in the past decade. Superconductivity at the oxide interfaces triggered by LaAlO3/SrTiO3 has become one of the promising routes for creation of new 2D superconductors. Also, the MBE grown metallic monolayers including FeSe are also offering a new platform of 2D superconductors. In the last two years, there appear a variety of monolayer/bilayer superconductors fabricated by CVD or mechanical exfoliation. Among these, electric field induced superconductivity by electric double layer transistor (EDLT) is a unique platform of 2D superconductivity, because of its ability of high density charge accumulation, and also because of the versatility in terms of materials, stemming from oxides to organics and layered chalcogenides. In this presentation, the following issues of electric filed induced superconductivity will be addressed; (1) Tunable carrier density, (2) Weak pinning, (3) Absence of inversion symmetry. (1) Since the sheet carrier density is quasi-continuously tunable from 0 to the order of 1014 cm-2, one is able to establish an electronic phase diagram of superconductivity, which will be compared with that of bulk superconductors. (2) The thickness of superconductivity can be estimated as 2 - 10 nm, dependent on materials, and is much smaller than the in-plane coherence length. Such a thin but low resistance at normal state results in extremely weak pinning beyond the dirty Boson model in the amorphous metallic films. (3) Due to the electric filed, the inversion symmetry is inherently broken in EDLT. This feature appears in the enhancement of Pauli limit of the upper critical field for the in-plane magnetic fields. In transition metal dichalcogenide with a substantial spin-orbit interactions, we were able to confirm the stabilization of Cooper pair due to its spin-valley locking. This work has been supported by Grant-in-Aid for Specially

  3. Preparation and characterization of CdSe colloidal quantum dots by pptical spectroscopy and 2D DOSY NMR

    NASA Astrophysics Data System (ADS)

    Geru, I.; Bordian, O.; Culeac, I.; Turta, C.; Verlan, V.; Barba, A.

    2015-02-01

    We present experimental results on preparation and characterization of colloidal CdSe quantum dots (QD) in organic solvent. CdSe QDs were synthesized following a modified literature method and have been characterized by UV-Vis absorption and photoluminescent (PL) spectroscopy, as well as by 2D Diffusion Ordered Spectroscopy (DOSY) NMR. The average CdSe particles size estimated from the UV-Vis absorption spectra was found to be in the range 2.28 - 2.92 nm, which correlates very well with the results obtained from NMR measurements. The PL spectrum for CdSe nanodots can be characterized by a narrow emission band with the peak maximum shifting from 508 to 566 nm in dependence of the CdSe nanoparticle size. The PL is dominated by a near-band-edge emission, accompanied by a weak broad band in the near IR, related to the surface shallow trap emission.

  4. Targeting multiple types of tumors using NKG2D-coated iron oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Wu, Ming-Ru; Cook, W. James; Zhang, Tong; Sentman, Charles L.

    2014-11-01

    Iron oxide nanoparticles (IONPs) hold great potential for cancer therapy. Actively targeting IONPs to tumor cells can further increase therapeutic efficacy and decrease off-target side effects. To target tumor cells, a natural killer (NK) cell activating receptor, NKG2D, was utilized to develop pan-tumor targeting IONPs. NKG2D ligands are expressed on many tumor types and its ligands are not found on most normal tissues under steady state conditions. The data showed that mouse and human fragment crystallizable (Fc)-fusion NKG2D (Fc-NKG2D) coated IONPs (NKG2D/NPs) can target multiple NKG2D ligand positive tumor types in vitro in a dose dependent manner by magnetic cell sorting. Tumor targeting effect was robust even under a very low tumor cell to normal cell ratio and targeting efficiency correlated with NKG2D ligand expression level on tumor cells. Furthermore, the magnetic separation platform utilized to test NKG2D/NP specificity has the potential to be developed into high throughput screening strategies to identify ideal fusion proteins or antibodies for targeting IONPs. In conclusion, NKG2D/NPs can be used to target multiple tumor types and magnetic separation platform can facilitate the proof-of-concept phase of tumor targeting IONP development.

  5. The role of the cytoskeleton in cellular force generation in 2D and 3D environments

    NASA Astrophysics Data System (ADS)

    Kraning-Rush, Casey M.; Carey, Shawn P.; Califano, Joseph P.; Smith, Brooke N.; Reinhart-King, Cynthia A.

    2011-02-01

    To adhere and migrate, cells generate forces through the cytoskeleton that are transmitted to the surrounding matrix. While cellular force generation has been studied on 2D substrates, less is known about cytoskeletal-mediated traction forces of cells embedded in more in vivo-like 3D matrices. Recent studies have revealed important differences between the cytoskeletal structure, adhesion, and migration of cells in 2D and 3D. Because the cytoskeleton mediates force, we sought to directly compare the role of the cytoskeleton in modulating cell force in 2D and 3D. MDA-MB-231 cells were treated with agents that perturbed actin, microtubules, or myosin, and analyzed for changes in cytoskeletal organization and force generation in both 2D and 3D. To quantify traction stresses in 2D, traction force microscopy was used; in 3D, force was assessed based on single cell-mediated collagen fibril reorganization imaged using confocal reflectance microscopy. Interestingly, even though previous studies have observed differences in cell behaviors like migration in 2D and 3D, our data indicate that forces generated on 2D substrates correlate with forces within 3D matrices. Disruption of actin, myosin or microtubules in either 2D or 3D microenvironments disrupts cell-generated force. These data suggest that despite differences in cytoskeletal organization in 2D and 3D, actin, microtubules and myosin contribute to contractility and matrix reorganization similarly in both microenvironments.

  6. Periodically sheared 2D Yukawa systems

    SciTech Connect

    Kovács, Anikó Zsuzsa; Hartmann, Peter; Donkó, Zoltán

    2015-10-15

    We present non-equilibrium molecular dynamics simulation studies on the dynamic (complex) shear viscosity of a 2D Yukawa system. We have identified a non-monotonic frequency dependence of the viscosity at high frequencies and shear rates, an energy absorption maximum (local resonance) at the Einstein frequency of the system at medium shear rates, an enhanced collective wave activity, when the excitation is near the plateau frequency of the longitudinal wave dispersion, and the emergence of significant configurational anisotropy at small frequencies and high shear rates.

  7. ENERGY LANDSCAPE OF 2D FLUID FORMS

    SciTech Connect

    Y. JIANG; ET AL

    2000-04-01

    The equilibrium states of 2D non-coarsening fluid foams, which consist of bubbles with fixed areas, correspond to local minima of the total perimeter. (1) The authors find an approximate value of the global minimum, and determine directly from an image how far a foam is from its ground state. (2) For (small) area disorder, small bubbles tend to sort inwards and large bubbles outwards. (3) Topological charges of the same sign repel while charges of opposite sign attract. (4) They discuss boundary conditions and the uniqueness of the pattern for fixed topology.

  8. Codon Constraints on Closed 2D Shapes,

    DTIC Science & Technology

    2014-09-26

    19843$ CODON CONSTRAINTS ON CLOSED 2D SHAPES Go Whitman Richards "I Donald D. Hoffman’ D T 18 Abstract: Codons are simple primitives for describing plane...RSONAL AUT"ORtIS) Richards, Whitman & Hoffman, Donald D. 13&. TYPE OF REPORT 13b. TIME COVERED N/A P8 AT F RRrT t~r. Ago..D,) is, PlE COUNT Reprint...outlines, if figure and ground are ignored. Later, we will address the problem of indexing identical codon descriptors that have different figure

  9. Bottom-up design of 2D organic photocatalysts for visible-light driven hydrogen evolution.

    PubMed

    Wang, Peng; Jiang, Xue; Zhao, Jijun

    2016-01-27

    To design two-dimensional (2D) organocatalysts, three series of covalent organic frameworks (COFs) are constructed using bottom-up strategies, i.e. molecular selection, tunable linkage, and functionalization. First-principles calculations are performed to confirm their photocatalytic activity under visible light. Two of our constructed 2D COF models (B1 and C3) are identified as a sufficiently efficient organocatalyst for visible light water splitting. The controllable construction of such COFs from suitable organic subunit, linkage, and functional groups paves the way for correlating band edge alignments and geometry parameters of 2D organic materials. Our theoretical prediction not only provides essential insights into designing 2D-COF photocatalysts for water splitting, but also sparks other technological applications for 2D organic materials.

  10. Bottom-up design of 2D organic photocatalysts for visible-light driven hydrogen evolution

    NASA Astrophysics Data System (ADS)

    Wang, Peng; Jiang, Xue; Zhao, Jijun

    2016-01-01

    To design two-dimensional (2D) organocatalysts, three series of covalent organic frameworks (COFs) are constructed using bottom-up strategies, i.e. molecular selection, tunable linkage, and functionalization. First-principles calculations are performed to confirm their photocatalytic activity under visible light. Two of our constructed 2D COF models (B1 and C3) are identified as a sufficiently efficient organocatalyst for visible light water splitting. The controllable construction of such COFs from suitable organic subunit, linkage, and functional groups paves the way for correlating band edge alignments and geometry parameters of 2D organic materials. Our theoretical prediction not only provides essential insights into designing 2D-COF photocatalysts for water splitting, but also sparks other technological applications for 2D organic materials.

  11. Detection of an endogenous urinary biomarker associated with CYP2D6 activity using global metabolomics

    PubMed Central

    Tay-Sontheimer, Jessica; Shireman, Laura M; Beyer, Richard P; Senn, Taurence; Witten, Daniela; Pearce, Robin E; Gaedigk, Andrea; Fomban, Cletus L Gana; Lutz, Justin D; Isoherranen, Nina; Thummel, Kenneth E; Fiehn, Oliver; Leeder, J Steven; Lin, Yvonne S

    2015-01-01

    Aim We sought to discover endogenous urinary biomarkers of human CYP2D6 activity. Patients & methods Healthy pediatric subjects (n = 189) were phenotyped using dextromethorphan and randomized for candidate biomarker selection and validation. Global urinary metabolomics was performed using liquid chromatography quadrupole time-of-flight mass spectrometry. Candidate biomarkers were tested in adults receiving fluoxetine, a CYP2D6 inhibitor. Results A biomarker, M1 (m/z 444.3102) was correlated with CYP2D6 activity in both the pediatric training and validation sets. Poor metabolizers had undetectable levels of M1, whereas it was present in subjects with other phenotypes. In adult subjects, a 9.56-fold decrease in M1 abundance was observed during CYP2D6 inhibition. Conclusion Identification and validation of M1 may provide a noninvasive means of CYP2D6 phenotyping. PMID:25521354

  12. Microwave Assisted 2D Materials Exfoliation

    NASA Astrophysics Data System (ADS)

    Wang, Yanbin

    Two-dimensional materials have emerged as extremely important materials with applications ranging from energy and environmental science to electronics and biology. Here we report our discovery of a universal, ultrafast, green, solvo-thermal technology for producing excellent-quality, few-layered nanosheets in liquid phase from well-known 2D materials such as such hexagonal boron nitride (h-BN), graphite, and MoS2. We start by mixing the uniform bulk-layered material with a common organic solvent that matches its surface energy to reduce the van der Waals attractive interactions between the layers; next, the solutions are heated in a commercial microwave oven to overcome the energy barrier between bulk and few-layers states. We discovered the minutes-long rapid exfoliation process is highly temperature dependent, which requires precise thermal management to obtain high-quality inks. We hypothesize a possible mechanism of this proposed solvo-thermal process; our theory confirms the basis of this novel technique for exfoliation of high-quality, layered 2D materials by using an as yet unknown role of the solvent.

  13. Drop size distribution comparisons between Parsivel and 2-D video disdrometers

    NASA Astrophysics Data System (ADS)

    Thurai, M.; Petersen, W. A.; Tokay, A.; Schultz, C.; Gatlin, P.

    2011-05-01

    Measurements from a 2-D video disdrometer (2DVD) have been used for drop size distribution (DSD) comparisons with co-located Parsivel measurements in Huntsville, Alabama. The comparisons were made in terms of the mass-weighted mean diameter, Dm, the standard deviation of the mass-spectrum, σm, and the rainfall rate, R, all based on 1-min DSD from the two instruments. Time series comparisons show close agreement in all three parameters for cases where R was less than 20 mm h-1. In four cases, discrepancies in all three parameters were seen for "heavy" events, with the Parsivel showing higher Dm, σm and R, when R reached high values (particularly above 30 mm h-1). Possible causes for the discrepancies include the presence of a small percentage of non-fully melted hydrometers, with higher than expected fall velocity and with very different axis ratios as compared with rain, indicating small hail or ice pellets or graupel. We also present here Parsivel-to-Parsivel comparisons as well as comparisons between two 2DVD instruments, namely a low-profile unit and the latest generation, "compact unit" which was installed at the same site in November 2009. The comparisons are included to assess the variability between the same types of instrument. Correlation coefficients and the fractional standard errors are compared.

  14. [Analysis of Three Polycyclic Aromatic Hydrocarbons in Solution Based on Two-Dimensional Fluorescence Correlation Spectroscopy].

    PubMed

    Zhou, Chang-hong; Zhao, Mei-rong; Yang, Ren-jie; Zhu, Wen-bi; Dong, Gui-mei

    2016-02-01

    Polycyclic aromatic hydrocarbons (PAHs) are listed as the priority pollutants. It is difficult to resolve effectively the peaks of PAHs by conventional one-dimensional fluorescence spectroscopy due to its low content and the overlapping fluorescence three mixed ystems and a total of 27 samples, are to be prepared with different concentrations of three PAHs. Concentrations of three PAHS are monotonically increasing or decreasing in each mixed system. Then the 2D fluorescence correlation spectrum of each mixed systems will be calculated under the perturbation of the concentration of anthracene, phenanthrene and pyrene in solution. There are seven strong autopeaks at 425, 402, 381, 373, 365, 393 and 347 nm in synchronous 2D correlation spectrum. The fluorescence peak of phenanthrene at 347 nm is uncovered in three mixed systems, so the band at 347 nm is to be used as clues for further assignment. According to positive or negative cross peaks at 347 nm in synchronous 2D correlation spectrum, we can know that the peaks at 402, 381, 425 and 452 nm are assigned to anthracene, the peaks at 373 and 393 nm are assigned to pyrene, and the peaks at 365, 356 and 347 nm are assigned to phenanthrene. The fluorescence peak of phenanthrene at 385 nm is shown in asynchronous 2D correlation spectrum; it means the spectral resolution of asynchronous spectrum is better than the synchronous spectrum. The results are that it is feasible to analyze serious overlapping multi-component PAHs using two-dimensional fluorescence correlation spectroscopy, which can be extended to the detection of other pollutants in the air.

  15. Transition to turbulence: 2D directed percolation

    NASA Astrophysics Data System (ADS)

    Chantry, Matthew; Tuckerman, Laurette; Barkley, Dwight

    2016-11-01

    The transition to turbulence in simple shear flows has been studied for well over a century, yet in the last few years has seen major leaps forward. In pipe flow, this transition shows the hallmarks of (1 + 1) D directed percolation, a universality class of continuous phase transitions. In spanwisely confined Taylor-Couette flow the same class is found, suggesting the phenomenon is generic to shear flows. However in plane Couette flow the largest simulations and experiments to-date find evidence for a discrete transition. Here we study a planar shear flow, called Waleffe flow, devoid of walls yet showing the fundamentals of planar transition to turbulence. Working with a quasi-2D yet Navier-Stokes derived model of this flow we are able to attack the (2 + 1) D transition problem. Going beyond the system sizes previously possible we find all of the required scalings of directed percolation and thus establish planar shears flow in this class.

  16. 2D quantum gravity from quantum entanglement.

    PubMed

    Gliozzi, F

    2011-01-21

    In quantum systems with many degrees of freedom the replica method is a useful tool to study the entanglement of arbitrary spatial regions. We apply it in a way that allows them to backreact. As a consequence, they become dynamical subsystems whose position, form, and extension are determined by their interaction with the whole system. We analyze, in particular, quantum spin chains described at criticality by a conformal field theory. Its coupling to the Gibbs' ensemble of all possible subsystems is relevant and drives the system into a new fixed point which is argued to be that of the 2D quantum gravity coupled to this system. Numerical experiments on the critical Ising model show that the new critical exponents agree with those predicted by the formula of Knizhnik, Polyakov, and Zamolodchikov.

  17. Simulation of Yeast Cooperation in 2D.

    PubMed

    Wang, M; Huang, Y; Wu, Z

    2016-03-01

    Evolution of cooperation has been an active research area in evolutionary biology in decades. An important type of cooperation is developed from group selection, when individuals form spatial groups to prevent them from foreign invasions. In this paper, we study the evolution of cooperation in a mixed population of cooperating and cheating yeast strains in 2D with the interactions among the yeast cells restricted to their small neighborhoods. We conduct a computer simulation based on a game theoretic model and show that cooperation is increased when the interactions are spatially restricted, whether the game is of a prisoner's dilemma, snow drifting, or mutual benefit type. We study the evolution of homogeneous groups of cooperators or cheaters and describe the conditions for them to sustain or expand in an opponent population. We show that under certain spatial restrictions, cooperator groups are able to sustain and expand as group sizes become large, while cheater groups fail to expand and keep them from collapse.

  18. 2D Electrostatic Actuation of Microshutter Arrays

    NASA Technical Reports Server (NTRS)

    Burns, Devin E.; Oh, Lance H.; Li, Mary J.; Jones, Justin S.; Kelly, Daniel P.; Zheng, Yun; Kutyrev, Alexander S.; Moseley, Samuel H.

    2015-01-01

    An electrostatically actuated microshutter array consisting of rotational microshutters (shutters that rotate about a torsion bar) were designed and fabricated through the use of models and experiments. Design iterations focused on minimizing the torsional stiffness of the microshutters, while maintaining their structural integrity. Mechanical and electromechanical test systems were constructed to measure the static and dynamic behavior of the microshutters. The torsional stiffness was reduced by a factor of four over initial designs without sacrificing durability. Analysis of the resonant behavior of the microshutter arrays demonstrates that the first resonant mode is a torsional mode occurring around 3000 Hz. At low vacuum pressures, this resonant mode can be used to significantly reduce the drive voltage necessary for actuation requiring as little as 25V. 2D electrostatic latching and addressing was demonstrated using both a resonant and pulsed addressing scheme.

  19. Graphene suspensions for 2D printing

    NASA Astrophysics Data System (ADS)

    Soots, R. A.; Yakimchuk, E. A.; Nebogatikova, N. A.; Kotin, I. A.; Antonova, I. V.

    2016-04-01

    It is shown that, by processing a graphite suspension in ethanol or water by ultrasound and centrifuging, it is possible to obtain particles with thicknesses within 1-6 nm and, in the most interesting cases, 1-1.5 nm. Analogous treatment of a graphite suspension in organic solvent yields eventually thicker particles (up to 6-10 nm thick) even upon long-term treatment. Using the proposed ink based on graphene and aqueous ethanol with ethylcellulose and terpineol additives for 2D printing, thin (~5 nm thick) films with sheet resistance upon annealing ~30 MΩ/□ were obtained. With the ink based on aqueous graphene suspension, the sheet resistance was ~5-12 kΩ/□ for 6- to 15-nm-thick layers with a carrier mobility of ~30-50 cm2/(V s).

  20. Canard configured aircraft with 2-D nozzle

    NASA Technical Reports Server (NTRS)

    Child, R. D.; Henderson, W. P.

    1978-01-01

    A closely-coupled canard fighter with vectorable two-dimensional nozzle was designed for enhanced transonic maneuvering. The HiMAT maneuver goal of a sustained 8g turn at a free-stream Mach number of 0.9 and 30,000 feet was the primary design consideration. The aerodynamic design process was initiated with a linear theory optimization minimizing the zero percent suction drag including jet effects and refined with three-dimensional nonlinear potential flow techniques. Allowances were made for mutual interference and viscous effects. The design process to arrive at the resultant configuration is described, and the design of a powered 2-D nozzle model to be tested in the LRC 16-foot Propulsion Wind Tunnel is shown.

  1. Numerical Evaluation of 2D Ground States

    NASA Astrophysics Data System (ADS)

    Kolkovska, Natalia

    2016-02-01

    A ground state is defined as the positive radial solution of the multidimensional nonlinear problem \\varepsilon propto k_ bot 1 - ξ with the function f being either f(u) =a|u|p-1u or f(u) =a|u|pu+b|u|2pu. The numerical evaluation of ground states is based on the shooting method applied to an equivalent dynamical system. A combination of fourth order Runge-Kutta method and Hermite extrapolation formula is applied to solving the resulting initial value problem. The efficiency of this procedure is demonstrated in the 1D case, where the maximal difference between the exact and numerical solution is ≈ 10-11 for a discretization step 0:00025. As a major application, we evaluate numerically the critical energy constant. This constant is defined as a functional of the ground state and is used in the study of the 2D Boussinesq equations.

  2. Metrology for graphene and 2D materials

    NASA Astrophysics Data System (ADS)

    Pollard, Andrew J.

    2016-09-01

    The application of graphene, a one atom-thick honeycomb lattice of carbon atoms with superlative properties, such as electrical conductivity, thermal conductivity and strength, has already shown that it can be used to benefit metrology itself as a new quantum standard for resistance. However, there are many application areas where graphene and other 2D materials, such as molybdenum disulphide (MoS2) and hexagonal boron nitride (h-BN), may be disruptive, areas such as flexible electronics, nanocomposites, sensing and energy storage. Applying metrology to the area of graphene is now critical to enable the new, emerging global graphene commercial world and bridge the gap between academia and industry. Measurement capabilities and expertise in a wide range of scientific areas are required to address this challenge. The combined and complementary approach of varied characterisation methods for structural, chemical, electrical and other properties, will allow the real-world issues of commercialising graphene and other 2D materials to be addressed. Here, examples of metrology challenges that have been overcome through a multi-technique or new approach are discussed. Firstly, the structural characterisation of defects in both graphene and MoS2 via Raman spectroscopy is described, and how nanoscale mapping of vacancy defects in graphene is also possible using tip-enhanced Raman spectroscopy (TERS). Furthermore, the chemical characterisation and removal of polymer residue on chemical vapour deposition (CVD) grown graphene via secondary ion mass spectrometry (SIMS) is detailed, as well as the chemical characterisation of iron films used to grow large domain single-layer h-BN through CVD growth, revealing how contamination of the substrate itself plays a role in the resulting h-BN layer. In addition, the role of international standardisation in this area is described, outlining the current work ongoing in both the International Organization of Standardization (ISO) and the

  3. Social communication in children with autism spectrum disorder (asd): Correlation between DSM-5 and autism classification system of functioning-social communication (ACSF:SC).

    PubMed

    Craig, Francesco; Fanizza, Isabella; Russo, Luigi; Lucarelli, Elisabetta; Alessandro, Lorenzo; Pasca, Maria Grazia; Trabacca, Antonio

    2017-03-07

    The aim of this study was to classify children with Autism Spectrum Disorder (ASD) according to Autism Classification System of Functioning: Social Communication (ACSF:SC) criteria, in order to investigate the association between social communication ability, ASD severity, adaptive functioning, cognitive abilities and psychoeducational profile. The severity of social communication impairment was specified through Diagnostic and Statistical Manual of Mental Disorders-5th edition (DSM-5) and ACSF:SC tool. The ADOS-2, Vineland-II and PEP-3 were administered to all participants. We found a positive correlation between DSM-5 levels and ACSF:SC-Typical Performance (r = 0.35; P = 0.007) and ACSF:SC-Capacity (r = 0.31; P = 0.01) levels. Children included in the five levels of ACSF:SC (Typical Performance and Capacity) showed statistically significant differences in ADOS-2 (Social Affect), Vineland-II (Communication and Socialization), and PEP-3 (Communication, motor skills, maladaptive behavior) scores. The results of this study indicate that ACSF:SC provide a better understanding of functional profile of children with ASD based on the social communication abilities. Children with greater severity of social communication showed more difficulty in adaptive behavior and psychoeducational profiles. In conclusion, the ACSF:SC could help clinicians and therapists not only to understand the strength and weakness of preschool children with ASD but also to devise specific treatment in order to promote their social integration. Autism Res 2017. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

  4. Network-based analysis reveals stronger local diffusion-based connectivity and different correlations with oral language skills in brains of children with high functioning autism spectrum disorders.

    PubMed

    Li, Hai; Xue, Zhong; Ellmore, Timothy M; Frye, Richard E; Wong, Stephen T C

    2014-02-01

    Neuroimaging has uncovered both long-range and short-range connectivity abnormalities in the brains of individuals with autism spectrum disorders (ASD). However, the precise connectivity abnormalities and the relationship between these abnormalities and cognition and ASD symptoms have been inconsistent across studies. Indeed, studies find both increases and decreases in connectivity, suggesting that connectivity changes in the ASD brain are not merely due to abnormalities in specific connections, but rather, due to changes in the structure of the network in which the brain areas interact (i.e., network topology). In this study, we examined the differences in the network topology between high-functioning ASD patients and age and gender matched typically developing (TD) controls. After quantitatively characterizing the whole-brain connectivity network using diffusion tensor imaging (DTI) data, we searched for brain regions with different connectivity between ASD and TD. A measure of oral language ability was then correlated with the connectivity changes to determine the functional significance of such changes. Whole-brain connectivity measures demonstrated greater local connectivity and shorter path length in ASD as compared to TD. Stronger local connectivity was found in ASD, especially in regions such as the left superior parietal lobule, the precuneus and angular gyrus, and the right supramarginal gyrus. The relationship between oral language ability and local connectivity within these regions was significantly different between ASD and TD. Stronger local connectivity was associated with better performance in ASD and poorer performance in TD. This study supports the notion that increased local connectivity is compensatory for supporting cognitive function in ASD.

  5. Determination of melamine of milk based on two-dimensional correlation infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Yang, Ren-jie; Liu, Rong; Xu, Kexin

    2012-03-01

    The adulteration of milk with harmful substances is a threat to public health and beyond question a serious crime. In order to develop a rapid, cost-effective, high-throughput analysis method for detecting of adulterants in milk, the discriminative analysis of melamine is established in milk based on the two-dimensional (2D) correlation infrared spectroscopy in present paper. Pure milk samples and adulterated milk samples with different content of melamine were prepared. Then the Fourier Transform Infrared spectra of all samples were measured at room temperature. The characteristics of pure milk and adulterated milk were studied by one-dimensional spectra. The 2D NIR and 2D IR correlation spectroscopy were calculated under the perturbation of adulteration concentration. In the range from 1400 to 1800 cm-1, two strong autopeaks were aroused by melamine in milk at 1464 cm-1 and 1560 cm-1 in synchronous spectrum. At the same time, the 1560 cm-1 band does not share cross peak with the 1464 cm-1 band, which further confirm that the two bands have the same origin. Also in the range from 4200 to 4800 cm-1, the autopeak was shown at 4648 cm-1 in synchronous spectrum of melamine in milk. 2D NIR-IR hetero-spectral correlation analysis confirmed that the bands at 1464, 1560 and 4648 cm-1 had the same origin. The results demonstrated that the adulterant can be discriminated correctly by 2D correlation infrared spectroscopy.

  6. Digit ratio (2D:4D), salivary testosterone, and handedness.

    PubMed

    Beaton, Alan A; Rudling, Nick; Kissling, Christian; Taurines, Regine; Thome, Johannes

    2011-03-01

    The length of the index finger relative to that of the ring finger, the 2D:4D ratio, has been taken to be a marker of the amount of testosterone (T) that was present in the foetal environment (Manning, Scutt, Wilson, & Lewis-Jones, 1998). It has also been suggested (Geschwind & Galaburda, 1987) that elevated levels of foetal T are associated with left-handedness and that adult levels of circulating T might relate to foetal levels (Jamison, Meier, & Campbell, 1993). We used multiple regression analyses to investigate whether there is any relationship between either left or right hand 2D:4D ratio and handedness. We also examined whether adult levels of salivary T (or cortisol, used as a control hormone) predict digit ratio and/or handedness. Although the 2D:4D ratio of neither the left nor the right hand was related to handedness, the difference between the digit ratios of the right and left hands, D(R-L), was a significant predictor of handedness and of the performance difference between the hands on a peg-moving task, supporting previous findings (Manning & Peters, 2009; Manning et al., 1998; Manning, Trivers, Thornhill, & Singh, 2000; Stoyanov, Marinov, & Pashalieva, 2009). Adult circulating T levels did not predict the digit ratio of the left or right hand; nor was there a significant relationship between concentrations of salivary T (or cortisol) and either hand preference or asymmetry in manual skill. We suggest that the association between D(R-L) and hand preference arises because D(R-L) is a correlate of sensitivity to T in the developing foetus.

  7. CBP/p300 acetyltransferases regulate the expression of NKG2D ligands on tumor cells

    PubMed Central

    Sauer, M; Schuldner, M; Hoffmann, N; Cetintas, A; Reiners, K S; Shatnyeva, O; Hallek, M; Hansen, H P; Gasser, S; von Strandmann, E P

    2017-01-01

    Tumor surveillance of natural killer (NK) cells is mediated by the cytotoxicity receptor natural-killer group 2 member D (NKG2D). Ligands for NKG2D are generally not expressed on healthy cells, but induced on the surface of malignant cells. To date, NKG2D ligand (NKG2D-L) induction was mainly described to depend on the activation of the DNA damage response, although the molecular mechanisms that regulate NKG2D-L expression remain largely unknown. Here, we show that the acetyltransferases CBP (CREB-binding protein) and p300 play a crucial role in the regulation of NKG2D-L on tumor cells. Loss of CBP/p300 decreased the basal cell surface expression of human ligands and reduced the upregulation of MICA/B and ULBP2 in response to histone deacetylase inhibitors or DNA damage. Furthermore, CBP/P300 deficiency abrogated the sensitivity of stressed cells to NK cell-mediated killing. CBP/p300 were also identified as major regulators of mouse NKG2D ligand RAE-1 in vitro and in vivo using the Eμ-Myc lymphoma model. Mechanistically, we observed an enhanced activation of the CBP/p300 binding transcription factor CREB (cAMP response element-binding protein) correlating to the NKG2D-L upregulation. Moreover, increased binding of CREB and CBP/p300 to NKG2D-L promoters and elevated histone acetylation were detectable. This study provides strong evidence for a major role of CBP and p300 in orchestrating NKG2D-L induction and consequently immunosurveillance of tumors in mice and humans. These findings might help to develop novel immunotherapeutic approaches against cancer. PMID:27477692

  8. 2-D Path Corrections for Local and Regional Coda Waves: A Test of Transportability

    SciTech Connect

    Mayeda, K M; Malagnini, L; Phillips, W S; Walter, W R; Dreger, D S; Morasca, P

    2005-07-13

    Reliable estimates of the seismic source spectrum are necessary for accurate magnitude, yield, and energy estimation. In particular, how seismic radiated energy scales with increasing earthquake size has been the focus of recent debate within the community and has direct implications on earthquake source physics studies as well as hazard mitigation. The 1-D coda methodology of Mayeda et al. [2003] has provided the lowest variance estimate of the source spectrum when compared against traditional approaches that use direct S-waves, thus making it ideal for networks that have sparse station distribution. The 1-D coda methodology has been mostly confined to regions of approximately uniform complexity. For larger, more geophysically complicated regions, 2-D path corrections may be required. We will compare performance of 1-D versus 2-D path corrections in a variety of regions. First, the complicated tectonics of the northern California region coupled with high quality broadband seismic data provides for an ideal ''apples-to-apples'' test of 1-D and 2-D path assumptions on direct waves and their coda. Next, we will compare results for the Italian Alps using high frequency data from the University of Genoa. For Northern California, we used the same station and event distribution and compared 1-D and 2-D path corrections and observed the following results: (1) 1-D coda results reduced the amplitude variance relative to direct S-waves by roughly a factor of 8 (800%); (2) Applying a 2-D correction to the coda resulted in up to 40% variance reduction from the 1-D coda results; (3) 2-D direct S-wave results, though better than 1-D direct waves, were significantly worse than the 1-D coda. We found that coda-based moment-rate source spectra derived from the 2-D approach were essentially identical to those from the 1-D approach for frequencies less than {approx}0.7-Hz, however for the high frequencies (0.7 {le} f {le} 8.0-Hz), the 2-D approach resulted in inter-station scatter

  9. Persistence Measures for 2d Soap Froth

    NASA Astrophysics Data System (ADS)

    Feng, Y.; Ruskin, H. J.; Zhu, B.

    Soap froths as typical disordered cellular structures, exhibiting spatial and temporal evolution, have been studied through their distributions and topological properties. Recently, persistence measures, which permit representation of the froth as a two-phase system, have been introduced to study froth dynamics at different length scales. Several aspects of the dynamics may be considered and cluster persistence has been observed through froth experiment. Using a direct simulation method, we have investigated persistent properties in 2D froth both by monitoring the persistence of survivor cells, a topologically independent measure, and in terms of cluster persistence. It appears that the area fraction behavior for both survivor and cluster persistence is similar for Voronoi froth and uniform froth (with defects). Survivor and cluster persistent fractions are also similar for a uniform froth, particularly when geometries are constrained, but differences observed for the Voronoi case appear to be attributable to the strong topological dependency inherent in cluster persistence. Survivor persistence, on the other hand, depends on the number rather than size and position of remaining bubbles and does not exhibit the characteristic decay to zero.

  10. SEM signal emulation for 2D patterns

    NASA Astrophysics Data System (ADS)

    Sukhov, Evgenii; Muelders, Thomas; Klostermann, Ulrich; Gao, Weimin; Braylovska, Mariya

    2016-03-01

    The application of accurate and predictive physical resist simulation is seen as one important use model for fast and efficient exploration of new patterning technology options, especially if fully qualified OPC models are not yet available at an early pre-production stage. The methodology of using a top-down CD-SEM metrology to extract the 3D resist profile information, such as the critical dimension (CD) at various resist heights, has to be associated with a series of presumptions which may introduce such small, but systematic CD errors. Ideally, the metrology effects should be carefully minimized during measurement process, or if possible be taken into account through proper metrology modeling. In this paper we discuss the application of a fast SEM signal emulation describing the SEM image formation. The algorithm is applied to simulated resist 3D profiles and produces emulated SEM image results for 1D and 2D patterns. It allows estimating resist simulation quality by comparing CDs which were extracted from the emulated and from the measured SEM images. Moreover, SEM emulation is applied for resist model calibration to capture subtle error signatures through dose and defocus. Finally, it should be noted that our SEM emulation methodology is based on the approximation of physical phenomena which are taking place in real SEM image formation. This approximation allows achieving better speed performance compared to a fully physical model.

  11. Competing coexisting phases in 2D water

    NASA Astrophysics Data System (ADS)

    Zanotti, Jean-Marc; Judeinstein, Patrick; Dalla-Bernardina, Simona; Creff, Gaëlle; Brubach, Jean-Blaise; Roy, Pascale; Bonetti, Marco; Ollivier, Jacques; Sakellariou, Dimitrios; Bellissent-Funel, Marie-Claire

    2016-05-01

    The properties of bulk water come from a delicate balance of interactions on length scales encompassing several orders of magnitudes: i) the Hydrogen Bond (HBond) at the molecular scale and ii) the extension of this HBond network up to the macroscopic level. Here, we address the physics of water when the three dimensional extension of the HBond network is frustrated, so that the water molecules are forced to organize in only two dimensions. We account for the large scale fluctuating HBond network by an analytical mean-field percolation model. This approach provides a coherent interpretation of the different events experimentally (calorimetry, neutron, NMR, near and far infra-red spectroscopies) detected in interfacial water at 160, 220 and 250 K. Starting from an amorphous state of water at low temperature, these transitions are respectively interpreted as the onset of creation of transient low density patches of 4-HBonded molecules at 160 K, the percolation of these domains at 220 K and finally the total invasion of the surface by them at 250 K. The source of this surprising behaviour in 2D is the frustration of the natural bulk tetrahedral local geometry and the underlying very significant increase in entropy of the interfacial water molecules.

  12. Competing coexisting phases in 2D water

    PubMed Central

    Zanotti, Jean-Marc; Judeinstein, Patrick; Dalla-Bernardina, Simona; Creff, Gaëlle; Brubach, Jean-Blaise; Roy, Pascale; Bonetti, Marco; Ollivier, Jacques; Sakellariou, Dimitrios; Bellissent-Funel, Marie-Claire

    2016-01-01

    The properties of bulk water come from a delicate balance of interactions on length scales encompassing several orders of magnitudes: i) the Hydrogen Bond (HBond) at the molecular scale and ii) the extension of this HBond network up to the macroscopic level. Here, we address the physics of water when the three dimensional extension of the HBond network is frustrated, so that the water molecules are forced to organize in only two dimensions. We account for the large scale fluctuating HBond network by an analytical mean-field percolation model. This approach provides a coherent interpretation of the different events experimentally (calorimetry, neutron, NMR, near and far infra-red spectroscopies) detected in interfacial water at 160, 220 and 250 K. Starting from an amorphous state of water at low temperature, these transitions are respectively interpreted as the onset of creation of transient low density patches of 4-HBonded molecules at 160 K, the percolation of these domains at 220 K and finally the total invasion of the surface by them at 250 K. The source of this surprising behaviour in 2D is the frustration of the natural bulk tetrahedral local geometry and the underlying very significant increase in entropy of the interfacial water molecules. PMID:27185018

  13. 2D ultrasonic elastography with lateral displacement estimation using statistics.

    PubMed

    Zhang, Zhihong; Liu, Haolin; Cheng, Yangjie

    2014-01-01

    Ultrasound elastography is the method of obtaining relative stiffness information of biological tissue, which plays an important role in early diagnosis. Generally, a gradient-based strain imaging algorithm assumes that motion only occurs in an axial direction. However, because tissue has different relative stiffness, the scatter presents lateral motion under high freehand compression. Therefore, errors occur in estimating the cross-correlation phase in the calculation window. A 2D elastography algorithm with lateral displacement estimation using statistics was proposed to reduce errors. The new method was investigated through simulation, and the experiment confirmed that errors introduced by lateral tissue movement have been greatly reduced with no sacrifice of real-time ultrasonic imaging quality.

  14. Effective Hamiltonians of 2D Spin Glass Clusters

    NASA Astrophysics Data System (ADS)

    Clement, Colin; Liarte, Danilo; Middleton, Alan; Sethna, James

    2015-03-01

    We have a method for directly identifying the clusters which are thought to dominate the dynamics of spin glasses. We also have a method for generating an effective Hamiltonian treating each cluster as an individual spin. We used these methods on a 2D Ising spin glass with Gaussian bonds. We study these systems by generating samples and correlation functions using a combination of Monte Carlo and high-performance numerically exact Pfaffian methods. With effective cluster Hamiltonians we can calculate the free energy asymmetry of the original clusters and perform a scaling analysis. The scaling exponents found are consistent with Domain-Wall Renormalization Group methods, and probe all length scales. We can also study the flow of these effective Hamiltonians by clustering the clustered spins, and we find that our hard spin Hamiltonians at high temperature retain accurate low-temperature fluctuations when compared to their parent models.

  15. 2D Seismic Reflection Data across Central Illinois

    SciTech Connect

    Smith, Valerie; Leetaru, Hannes

    2014-09-30

    In a continuing collaboration with the Midwest Geologic Sequestration Consortium (MGSC) on the Evaluation of the Carbon Sequestration Potential of the Cambro-Ordovician Strata of the Illinois and Michigan Basins project, Schlumberger Carbon Services and WesternGeco acquired two-dimensional (2D) seismic data in the Illinois Basin. This work included the design, acquisition and processing of approximately 125 miles of (2D) seismic reflection surveys running west to east in the central Illinois Basin. Schlumberger Carbon Services and WesternGeco oversaw the management of the field operations (including a pre-shoot planning, mobilization, acquisition and de-mobilization of the field personnel and equipment), procurement of the necessary permits to conduct the survey, post-shoot closure, processing of the raw data, and provided expert consultation as needed in the interpretation of the delivered product. Three 2D seismic lines were acquired across central Illinois during November and December 2010 and January 2011. Traversing the Illinois Basin, this 2D seismic survey was designed to image the stratigraphy of the Cambro-Ordovician sections and also to discern the basement topography. Prior to this survey, there were no regionally extensive 2D seismic data spanning this section of the Illinois Basin. Between the NW side of Morgan County and northwestern border of Douglas County, these seismic lines ran through very rural portions of the state. Starting in Morgan County, Line 101 was the longest at 93 miles in length and ended NE of Decatur, Illinois. Line 501 ran W-E from the Illinois Basin – Decatur Project (IBDP) site to northwestern Douglas County and was 25 miles in length. Line 601 was the shortest and ran N-S past the IBDP site and connected lines 101 and 501. All three lines are correlated to well logs at the IBDP site. Originally processed in 2011, the 2D seismic profiles exhibited a degradation of signal quality below ~400 millisecond (ms) which made

  16. Radiofrequency Spectroscopy and Thermodynamics of Fermi Gases in the 2D to Quasi-2D Dimensional Crossover

    NASA Astrophysics Data System (ADS)

    Cheng, Chingyun; Kangara, Jayampathi; Arakelyan, Ilya; Thomas, John

    2016-05-01

    We tune the dimensionality of a strongly interacting degenerate 6 Li Fermi gas from 2D to quasi-2D, by adjusting the radial confinement of pancake-shaped clouds to control the radial chemical potential. In the 2D regime with weak radial confinement, the measured pair binding energies are in agreement with 2D-BCS mean field theory, which predicts dimer pairing energies in the many-body regime. In the qausi-2D regime obtained with increased radial confinement, the measured pairing energy deviates significantly from 2D-BCS theory. In contrast to the pairing energy, the measured radii of the cloud profiles are not fit by 2D-BCS theory in either the 2D or quasi-2D regimes, but are fit in both regimes by a beyond mean field polaron-model of the free energy. Supported by DOE, ARO, NSF, and AFOSR.

  17. Use of marginal distributions constrained optimization (MADCO) for accelerated 2D MRI relaxometry and diffusometry

    NASA Astrophysics Data System (ADS)

    Benjamini, Dan; Basser, Peter J.

    2016-10-01

    Measuring multidimensional (e.g., 2D) relaxation spectra in NMR and MRI clinical applications is a holy grail of the porous media and biomedical MR communities. The main bottleneck is the inversion of Fredholm integrals of the first kind, an ill-conditioned problem requiring large amounts of data to stabilize a solution. We suggest a novel experimental design and processing framework to accelerate and improve the reconstruction of such 2D spectra that uses a priori information from the 1D projections of spectra, or marginal distributions. These 1D marginal distributions provide powerful constraints when 2D spectra are reconstructed, and their estimation requires an order of magnitude less data than a conventional 2D approach. This marginal distributions constrained optimization (MADCO) methodology is demonstrated here with a polyvinylpyrrolidone-water phantom that has 3 distinct peaks in the 2D D-T1 space. The stability, sensitivity to experimental parameters, and accuracy of this new approach are compared with conventional methods by serially subsampling the full data set. While the conventional, unconstrained approach performed poorly, the new method had proven to be highly accurate and robust, only requiring a fraction of the data. Additionally, synthetic T1 -T2 data are presented to explore the effects of noise on the estimations, and the performance of the proposed method with a smooth and realistic 2D spectrum. The proposed framework is quite general and can also be used with a variety of 2D MRI experiments (D-T2,T1 -T2, D -D, etc.), making these potentially feasible for preclinical and even clinical applications for the first time.

  18. Relative dispersion in 2D stochastic flows

    NASA Astrophysics Data System (ADS)

    Piterbarg, L. I.

    We investigate the relative dispersion for two types of stochastic flows—Brownian flow (Kraichnan model) and a flow with memory (inertial particles). In the first case well-known asymptotics are rigorously derived for a self-similar spectrum of the velocity field by using a half-century-old Feller's theorem. Exact limits of the asymptotics and exact values for dimensionless constants are obtained. The second part of the paper addresses a relatively new object: the first-order Markov stochastic flow modelling inertial particle motion. Both local and non-local dynamics are investigated. In the first case an exact exponential asymptotic is obtained for the relative dispersion. In turn, two regimes are considered in the case of non-smooth forcing: weak and strong turbulence. For weak turbulence the obtained asymptotic of relative dispersion is similar to that of the Brownian flow. As for strong turbulence, an upper bound is obtained for the scaling of relative dispersion.

  19. Graphene and Other 2D Colloids: Liquid Crystals and Macroscopic Fibers.

    PubMed

    Liu, Yingjun; Xu, Zhen; Gao, Weiwei; Cheng, Zhengdong; Gao, Chao

    2017-02-24

    Two-dimensional colloidal nanomaterials are running into renaissance after the enlightening researches of graphene. Macroscopic one-dimensional fiber is an optimal ordered structural form to express the in-plane merits of 2D nanomaterials, and the formation of liquid crystals (LCs) allows the creation of continuous fibers. In the correlated system from LCs to fibers, understanding their macroscopic organizing behavior and transforming them into new solid fibers is greatly significant for applications. Herein, we retrospect the history of 2D colloids and discuss about the concept of 2D nanomaterial fibers in the context of LCs, elaborating the motivation, principle and possible strategies of fabrication. Then we highlight the creation, development and typical applications of graphene fibers. Additionally, the latest advances of other 2D nanomaterial fibers are also summarized. Finally, conclusions, challenges and perspectives are provided to show great expectations of better and more fibrous materials of 2D nanomaterials. This review gives a comprehensive retrospect of the past century-long effort about the whole development of 2D colloids, and plots a clear roadmap - "lamellar solid - LCs - macroscopic fibers - flexible devices", which will certainly open a new era of structural-multifunctional application for the conventional 2D colloids.

  20. Probing interband coulomb interactions in semiconductor nanostructures with 2D double-quantum coherence spectroscopy.

    PubMed

    Velizhanin, Kirill A; Piryatinski, Andrei

    2011-05-12

    Employing the interband exciton scattering model, we have derived a closed set of equations determining the 2D double-quantum coherence signal sensitive to the interband Coulomb interactions (i.e., many-body Coulomb interactions leading to the couplings between exciton and biexciton bands) in semiconductor nanostructures such as nanocrystals, quantum wires, wells, and carbon nanotubes. Our general analysis of 2D double-quantum coherence resonances has demonstrated that the interband Coulomb interactions lead to new cross-peaks whose appearance can be interpreted as a result of exciton and biexciton state mixing. The presence of the strongly coupled resonant states and weakly coupled background of off-resonant states can significantly simplify cross-peak analysis by eliminating the congested background spectrum. Our simulations of the 2D double-quantum coherence signal in PbSe NCs have validated this approach.

  1. Micro-reflectance and transmittance spectroscopy: a versatile and powerful tool to characterize 2D materials

    NASA Astrophysics Data System (ADS)

    Frisenda, Riccardo; Niu, Yue; Gant, Patricia; Molina-Mendoza, Aday J.; Schmidt, Robert; Bratschitsch, Rudolf; Liu, Jinxin; Fu, Lei; Dumcenco, Dumitru; Kis, Andras; Perez De Lara, David; Castellanos-Gomez, Andres

    2017-02-01

    Optical spectroscopy techniques such as differential reflectance and transmittance have proven to be very powerful techniques for studying 2D materials. However, a thorough description of the experimental setups needed to carry out these measurements is lacking in the literature. We describe a versatile optical microscope setup for carrying out differential reflectance and transmittance spectroscopy in 2D materials with a lateral resolution of ~1 µm in the visible and near-infrared part of the spectrum. We demonstrate the potential of the presented setup to determine the number of layers of 2D materials and characterize their fundamental optical properties, such as excitonic resonances. We illustrate its performance by studying mechanically exfoliated and chemical vapor-deposited transition metal dichalcogenide samples.

  2. 2D discrete Fourier transform on sliding windows.

    PubMed

    Park, Chun-Su

    2015-03-01

    Discrete Fourier transform (DFT) is the most widely used method for determining the frequency spectra of digital signals. In this paper, a 2D sliding DFT (2D SDFT) algorithm is proposed for fast implementation of the DFT on 2D sliding windows. The proposed 2D SDFT algorithm directly computes the DFT bins of the current window using the precalculated bins of the previous window. Since the proposed algorithm is designed to accelerate the sliding transform process of a 2D input signal, it can be directly applied to computer vision and image processing applications. The theoretical analysis shows that the computational requirement of the proposed 2D SDFT algorithm is the lowest among existing 2D DFT algorithms. Moreover, the output of the 2D SDFT is mathematically equivalent to that of the traditional DFT at all pixel positions.

  3. 2D electron temperature diagnostic using soft x-ray imaging technique

    SciTech Connect

    Nishimura, K. Sanpei, A. Tanaka, H.; Ishii, G.; Kodera, R.; Ueba, R.; Himura, H.; Masamune, S.; Ohdachi, S.; Mizuguchi, N.

    2014-03-15

    We have developed a two-dimensional (2D) electron temperature (T{sub e}) diagnostic system for thermal structure studies in a low-aspect-ratio reversed field pinch (RFP). The system consists of a soft x-ray (SXR) camera with two pin holes for two-kinds of absorber foils, combined with a high-speed camera. Two SXR images with almost the same viewing area are formed through different absorber foils on a single micro-channel plate (MCP). A 2D T{sub e} image can then be obtained by calculating the intensity ratio for each element of the images. We have succeeded in distinguishing T{sub e} image in quasi-single helicity (QSH) from that in multi-helicity (MH) RFP states, where the former is characterized by concentrated magnetic fluctuation spectrum and the latter, by broad spectrum of edge magnetic fluctuations.

  4. MAGNUM2D. Radionuclide Transport Porous Media

    SciTech Connect

    Langford, D.W.; Baca, R.G.

    1989-03-01

    MAGNUM2D was developed to analyze thermally driven fluid motion in the deep basalts below the Paco Basin at the Westinghouse Hanford Site. Has been used in the Basalt Waste Isolation Project to simulate nonisothermal groundwater flow in a heterogeneous anisotropic medium and heat transport in a water/rock system near a high level nuclear waste repository. Allows three representations of the hydrogeologic system: an equivalent porous continuum, a system of discrete, unfilled, and interconnecting fractures separated by impervious rock mass, and a low permeability porous continuum with several discrete, unfilled fractures traversing the medium. The calculations assume local thermodynamic equilibrium between the rock and groundwater, nonisothermal Darcian flow in the continuum portions of the rock, and nonisothermal Poiseuille flow in discrete unfilled fractures. In addition, the code accounts for thermal loading within the elements, zero normal gradient and fixed boundary conditions for both temperature and hydraulic head, and simulation of the temperature and flow independently. The Q2DGEOM preprocessor was developed to generate, modify, plot and verify quadratic two dimensional finite element geometries. The BCGEN preprocessor generates the boundary conditions for head and temperature and ICGEN generates the initial conditions. The GRIDDER postprocessor interpolates nonregularly spaced nodal flow and temperature data onto a regular rectangular grid. CONTOUR plots and labels contour lines for a function of two variables and PARAM plots cross sections and time histories for a function of time and one or two spatial variables. NPRINT generates data tables that display the data along horizontal or vertical cross sections. VELPLT differentiates the hydraulic head and buoyancy data and plots the velocity vectors. The PATH postprocessor plots flow paths and computes the corresponding travel times.

  5. MAGNUM2D. Radionuclide Transport Porous Media

    SciTech Connect

    Langford, D.W.; Baca, R.G.

    1988-08-01

    MAGNUM2D was developed to analyze thermally driven fluid motion in the deep basalts below the Paco Basin at the Westinghouse Hanford Site. Has been used in the Basalt Waste Isolation Project to simulate nonisothermal groundwater flow in a heterogeneous anisotropic medium and heat transport in a water/rock system near a high level nuclear waste repository. Allows three representations of the hydrogeologic system: an equivalent porous continuum, a system of discrete, unfilled, and interconnecting fractures separated by impervious rock mass, and a low permeability porous continuum with several discrete, unfilled fractures traversing the medium. The calculation assumes local thermodynamic equilibrium between the rock and groundwater, nonisothermal Darcian flow in the continuum portions of the rock, and nonisothermal Poiseuille flow in discrete unfilled fractures. In addition, the code accounts for thermal loading within the elements, zero normal gradient and fixed boundary conditions for both temperature and hydraulic head, and simulation of the temperature and flow independently. The Q2DGEOM preprocessor was developed to generate, modify, plot and verify quadratic two dimensional finite element geometries. The BCGEN preprocessor generates the boundary conditions for head and temperature and ICGEN generates the initial conditions. The GRIDDER postprocessor interpolates nonregularly spaced nodal flow and temperature data onto a regular rectangular grid. CONTOUR plots and labels contour lines for a function of two variables and PARAM plots cross sections and time histories for a function of time and one or two spatial variables. NPRINT generates data tables that display the data along horizontal or vertical cross sections. VELPLT differentiates the hydraulic head and buoyancy data and plots the velocity vectors. The PATH postprocessor plots flow paths and computes the corresponding travel times.

  6. Generates 2D Input for DYNA NIKE & TOPAZ

    SciTech Connect

    Hallquist, J. O.; Sanford, Larry

    1996-07-15

    MAZE is an interactive program that serves as an input and two-dimensional mesh generator for DYNA2D, NIKE2D, TOPAZ2D, and CHEMICAL TOPAZ2D. MAZE also generates a basic template for ISLAND input. MAZE has been applied to the generation of input data to study the response of two-dimensional solids and structures undergoing finite deformations under a wide variety of large deformation transient dynamic and static problems and heat transfer analyses.

  7. MAZE96. Generates 2D Input for DYNA NIKE & TOPAZ

    SciTech Connect

    Sanford, L.; Hallquist, J.O.

    1992-02-24

    MAZE is an interactive program that serves as an input and two-dimensional mesh generator for DYNA2D, NIKE2D, TOPAZ2D, and CHEMICAL TOPAZ2D. MAZE also generates a basic template for ISLAND input. MAZE has been applied to the generation of input data to study the response of two-dimensional solids and structures undergoing finite deformations under a wide variety of large deformation transient dynamic and static problems and heat transfer analyses.

  8. NIKE2D96. Static & Dynamic Response of 2D Solids

    SciTech Connect

    Raboin, P.; Engelmann, B.; Halquist, J.O.

    1992-01-24

    NIKE2D is an implicit finite-element code for analyzing the finite deformation, static and dynamic response of two-dimensional, axisymmetric, plane strain, and plane stress solids. The code is fully vectorized and available on several computing platforms. A number of material models are incorporated to simulate a wide range of material behavior including elasto-placicity, anisotropy, creep, thermal effects, and rate dependence. Slideline algorithms model gaps and sliding along material interfaces, including interface friction, penetration and single surface contact. Interactive-graphics and rezoning is included for analyses with large mesh distortions. In addition to quasi-Newton and arc-length procedures, adaptive algorithms can be defined to solve the implicit equations using the solution language ISLAND. Each of these capabilities and more make NIKE2D a robust analysis tool.

  9. Antenna coupled detectors for 2D staring focal plane arrays

    NASA Astrophysics Data System (ADS)

    Gritz, Michael A.; Kolasa, Borys; Lail, Brian; Burkholder, Robert; Chen, Leonard

    2013-06-01

    Millimeter-wave (mmW)/sub-mmW/THz region of the electro-magnetic spectrum enables imaging thru clothing and other obscurants such as fog, clouds, smoke, sand, and dust. Therefore considerable interest exists in developing low cost millimeter-wave imaging (MMWI) systems. Previous MMWI systems have evolved from crude mechanically scanned, single element receiver systems into very complex multiple receiver camera systems. Initial systems required many expensive mmW integrated-circuit low-noise amplifiers. In order to reduce the cost and complexity of the existing systems, attempts have been made to develop new mmW imaging sensors employing direct detection arrays. In this paper, we report on Raytheon's recent development of a unique focal plane array technology, which operates broadly from the mmW through the sub-mmW/THz region. Raytheon's innovative nano-antenna based detector enables low cost production of 2D staring mmW focal plane arrays (mmW FPA), which not only have equivalent sensitivity and performance to existing MMWI systems, but require no mechanical scanning.

  10. 2D-ELDOR detection of magnetization transfer of nitroxides in disordered solid polymers

    NASA Astrophysics Data System (ADS)

    Maresch, G. G.; Weber, M.; Dubinskii, A. A.; Spiess, H. W.

    1992-05-01

    Two-dimensional electron—electron double resonance (2D-ELDOR) experiments on nitroxide spin labels in solid liquid-crystalline side-group polymers have been performed employing narrow-band microwave excitation pulses followed by a rapid magnetic field step during a mixing time and detection at the new selected point of the EPR spectrum. Information about magnetization transfer throughout the full EPR spectrum is obtained by sweeping both pumping and detecting fields. In the two-dimensional representation of experimental ELDOR data, the different processes causing magnetization transfer through the EPR spectrum, i.e. electron spin diffusion, nuclear relaxation, and slow rotational motions lead to different patterns and can be distinguished by recording 2D-ELDOR spectra as a function of temperature. In the specific system studied, the 2D-ELDOR spectra show the dominance of magnetization transfer between states with close molecular orientations but different nitrogen nuclear spin projections caused by flips of nuclear spins. The results are discussed in terms of dynamic processes in glasses.

  11. Divergences in KIR2D+ natural killer and KIR2D+CD8+ T-cell reconstitution following liver transplantation.

    PubMed

    López-Álvarez, M R; Campillo, J A; Legaz, I; Blanco-García, R M; Salgado-Cecilia, G; Bolarín, J M; Gimeno, L; Gil, J; García-Alonso, A M; Muro, M; Alvarez-López, M R; Miras, M; Minguela, A

    2011-03-01

    Natural killer (NK) and CD8(+) T cells may be active elements in the allograft response, but little is known about their role in liver transplantation. Some of these cells express killer immunoglobulin-like receptors (KIRs), which after binding specific ligands may transmit inhibitory/activating signals. In this study, circulating NK and CD8(+) T cells expressing CD158a/h (KIR2DL1/S1) or CD158b/j (KIR2DL2/3/S(2)) receptors were analyzed in 142 liver recipients by flow cytometry. They were underrepresented in patients before transplantation, but following transplantation, whereas the KIR2D(+) NK subsets experienced a late recuperation (day 365) mainly in C2-homozygous patients developing early acute rejection, recovery of the 2 CD8(+)KIR2D(+) T cells started earlier, showing significant differences on day 365 between patients without acute rejection and those suffering from it (p = 0.004 and p < 0.0001, respectively). These differences were also evident when the human leukocute antigen-C genotypes of the recipient were considered. In conclusion, whereas the late recovery of KIR2D(+) NK cells in C2/C2 patients appears to be linked to acute rejection, the increase in early CD8(+)KIR2D(+) T cells in overall liver recipients correlates with a most successful early graft outcome. Therefore, monitoring of KIR2D(+) cells appears to be a useful tool for liver transplant follow-up.

  12. Ultraviolet light action spectra for neoplastic transformation and lethality of Syrian hamster embryo cells correlate with spectrum for pyrimidine dimer formation in cellular DNA.

    PubMed Central

    Doniger, J; Jacobson, E D; Krell, K; DiPaolo, J A

    1981-01-01

    Action spectra were determined for neoplastic transformation, production of pyrimidine dimers, and lethality in Syrian hamster embryo cells. Of wavelengths between 240 and 313 nm, the most effective were 265 and 270. The relative sensitivities per quantum for transformation, pyrimidine dimer production, and lethality were essentially the same at each of the wavelengths tested. This action spectrum for transformation, which is relevant to carcinogenesis, is similar to spectra obtained previously by measuring other cellular responses in either microbial or mammalian systems. Because the action spectra for cytotoxicity and transformation are the same as the spectrum for dimer production, DNA is suggested as the target for all these processes. PMID:6941297

  13. Socioeconomic status is associated with striatal dopamine D2/D3 receptors in healthy volunteers but not in cocaine abusers

    PubMed Central

    Wiers, Corinde E.; Shokri-Kojori, Ehsan; Cabrera, Elizabeth; Cunningham, Samantha; Wong, Christopher; Tomasi, Dardo; Wang, Gene-Jack; Volkow, Nora D.

    2016-01-01

    Positron emission tomography (PET) studies in animals and humans have shown that social status is associated with striatal dopamine D2/D3 receptor (D2/D3R) availability. That is, higher social hierarchy and higher scores on questionnaires assessing social status correlated positively with striatal D2/D3R availability in animals and humans respectively. Furthermore, subordinate monkeys were vulnerable to cocaine self-administration, suggesting that alternations in social hierarchy can change D2/D3R availability and vulnerability to cocaine use. Here, we investigated whether socioeconomic status (SES) measured with the Hollingshead scale is associated with striatal D2D/3R availability using [11C]raclopride PET in 38 cocaine abusers and 42 healthy controls matched for age and education. Compared to controls, cocaine abusers showed lower D2/D3R availability in the caudate, putamen and ventral striatum (all p≤.001). Despite matching groups for education, SES scores were lower in cocaine abusers than controls (p<.001). In the control group only, SES scores significantly correlated with D2/D3R in caudate (r=.35, p=.024) and putamen (r=.39, p=.011) but not in ventral striatum (p=.61); all corrected for age. The study confirms that SES is associated with striatal D2/D3R availability in healthy human volunteers. However, reductions in D2/D3R availability in cocaine abusers may be driven by factors other than SES such as chronic cocaine exposure. PMID:26828302

  14. CYP2D7 Sequence Variation Interferes with TaqMan CYP2D6*15 and *35 Genotyping

    PubMed Central

    Riffel, Amanda K.; Dehghani, Mehdi; Hartshorne, Toinette; Floyd, Kristen C.; Leeder, J. Steven; Rosenblatt, Kevin P.; Gaedigk, Andrea

    2016-01-01

    TaqMan™ genotyping assays are widely used to genotype CYP2D6, which encodes a major drug metabolizing enzyme. Assay design for CYP2D6 can be challenging owing to the presence of two pseudogenes, CYP2D7 and CYP2D8, structural and copy number variation and numerous single nucleotide polymorphisms (SNPs) some of which reflect the wild-type sequence of the CYP2D7 pseudogene. The aim of this study was to identify the mechanism causing false-positive CYP2D6*15 calls and remediate those by redesigning and validating alternative TaqMan genotype assays. Among 13,866 DNA samples genotyped by the CompanionDx® lab on the OpenArray platform, 70 samples were identified as heterozygotes for 137Tins, the key SNP of CYP2D6*15. However, only 15 samples were confirmed when tested with the Luminex xTAG CYP2D6 Kit and sequencing of CYP2D6-specific long range (XL)-PCR products. Genotype and gene resequencing of CYP2D6 and CYP2D7-specific XL-PCR products revealed a CC>GT dinucleotide SNP in exon 1 of CYP2D7 that reverts the sequence to CYP2D6 and allows a TaqMan assay PCR primer to bind. Because CYP2D7 also carries a Tins, a false-positive mutation signal is generated. This CYP2D7 SNP was also responsible for generating false-positive signals for rs769258 (CYP2D6*35) which is also located in exon 1. Although alternative CYP2D6*15 and *35 assays resolved the issue, we discovered a novel CYP2D6*15 subvariant in one sample that carries additional SNPs preventing detection with the alternate assay. The frequency of CYP2D6*15 was 0.1% in this ethnically diverse U.S. population sample. In addition, we also discovered linkage between the CYP2D7 CC>GT dinucleotide SNP and the 77G>A (rs28371696) SNP of CYP2D6*43. The frequency of this tentatively functional allele was 0.2%. Taken together, these findings emphasize that regardless of how careful genotyping assays are designed and evaluated before being commercially marketed, rare or unknown SNPs underneath primer and/or probe regions can impact

  15. CYP2D7 Sequence Variation Interferes with TaqMan CYP2D6 (*) 15 and (*) 35 Genotyping.

    PubMed

    Riffel, Amanda K; Dehghani, Mehdi; Hartshorne, Toinette; Floyd, Kristen C; Leeder, J Steven; Rosenblatt, Kevin P; Gaedigk, Andrea

    2015-01-01

    TaqMan™ genotyping assays are widely used to genotype CYP2D6, which encodes a major drug metabolizing enzyme. Assay design for CYP2D6 can be challenging owing to the presence of two pseudogenes, CYP2D7 and CYP2D8, structural and copy number variation and numerous single nucleotide polymorphisms (SNPs) some of which reflect the wild-type sequence of the CYP2D7 pseudogene. The aim of this study was to identify the mechanism causing false-positive CYP2D6 (*) 15 calls and remediate those by redesigning and validating alternative TaqMan genotype assays. Among 13,866 DNA samples genotyped by the CompanionDx® lab on the OpenArray platform, 70 samples were identified as heterozygotes for 137Tins, the key SNP of CYP2D6 (*) 15. However, only 15 samples were confirmed when tested with the Luminex xTAG CYP2D6 Kit and sequencing of CYP2D6-specific long range (XL)-PCR products. Genotype and gene resequencing of CYP2D6 and CYP2D7-specific XL-PCR products revealed a CC>GT dinucleotide SNP in exon 1 of CYP2D7 that reverts the sequence to CYP2D6 and allows a TaqMan assay PCR primer to bind. Because CYP2D7 also carries a Tins, a false-positive mutation signal is generated. This CYP2D7 SNP was also responsible for generating false-positive signals for rs769258 (CYP2D6 (*) 35) which is also located in exon 1. Although alternative CYP2D6 (*) 15 and (*) 35 assays resolved the issue, we discovered a novel CYP2D6 (*) 15 subvariant in one sample that carries additional SNPs preventing detection with the alternate assay. The frequency of CYP2D6 (*) 15 was 0.1% in this ethnically diverse U.S. population sample. In addition, we also discovered linkage between the CYP2D7 CC>GT dinucleotide SNP and the 77G>A (rs28371696) SNP of CYP2D6 (*) 43. The frequency of this tentatively functional allele was 0.2%. Taken together, these findings emphasize that regardless of how careful genotyping assays are designed and evaluated before being commercially marketed, rare or unknown SNPs underneath primer

  16. 2D-fractal based algorithms for nanoparticles characterization

    NASA Astrophysics Data System (ADS)

    Bonifazi, Giuseppe; Serranti, Silvia

    2014-02-01

    Fractal geometry concerns the study of non-Euclidean geometrical figures generated by a recursive sequence of mathematical operations. The proposed 2D-fractal approach was applied to characterise the image structure and texture generated by fine and ultra-fine particles when impacting on a flat surface. The work was developed with reference to particles usually produced by ultra-fine milling addressed to generate nano-particles population. In order to generate different particle populations to utilize in the study, specific milling actions have been thus performed adopting different milling actions and utilising different materials, both in terms of original size class distribution and chemical-physical attributes. The aim of the work was to develop a simple, reliable and low cost analytical set of procedures with the ability to establish correlations between particles detected by fractal characteristics and their milled-induced-properties (i.e. size class distribution, shape, surface properties, etc.). Such logic should constitute the core of a control engine addressed to realize a full monitoring of the milling process as well as to establish correlation between operative parameters, fed and resulting products characteristics.

  17. 2-d Packing of Prolate Granular Materials

    NASA Astrophysics Data System (ADS)

    Franklin, Scott

    2002-11-01

    Piles of extremely prolate (aspect ratio α=L/D>10) granular materials are qualitatively different than lower aspect-ratio particles. One can run a hand through sand, for example, but not through nails. In three dimensions this transition occurs at α ˜ 35. We investigate the two-dimensional packing of particles with aspect ratios ranging from 10-44, comparing experiments with Monte-Carlo simulations. Particle alignment can quantified by an orientational order correlation function and related to the packing fraction. In both simulation and experiment the correlation between particle orientation decays after a distance of two particle lengths. We also quantify the distribution of voids in the pile, finding it to follow a power law with exponent -β=-2.370.05. Dynamic experiments involve rotating the pile. Particles with aspect ratio as low as 10 do not appear to have a well defined angle of repose, suggesting that the transition to rigidity occurs at a far lower aspect ratio in two dimensions. Preliminary results from this experiment will be presented.

  18. Zellweger Spectrum

    MedlinePlus

    ... Resources Conference News Contact Us Donate The Zellweger Spectrum Zellweger Syndrome, Neonatal Adrenoleukodystrophy (NALD), and Infantile Refsum’s ... of severity of disease. What causes the Zellweger spectrum of diseases? As we mentioned, disorders of the ...

  19. HI Intensity Mapping: Parkes-2dFGRS and BAO science

    NASA Astrophysics Data System (ADS)

    Li, Yi-Chao; Staveley-Smith, Lister; Pen, Ue-Li; Chang, Tzu-Ching; Peterson, Jeff; Bandura, Kevin; Chen, Xuelei; Wang, Xin; Price, Danny; Montero-Castano, Maria; Anderson, Christopher; Voytek, Tabitha; Masui, Kiyoshi; Switzer, Eric; Wu, Feng-Quan; Timbie, Peter; Liao, Yu-Wei Victor; Li, zhigang

    2012-10-01

    We propose to scan the 2dF survey field with Parkes multibeam in driftscan mode to make a map of cosmological large scale structure. This allows a statistical detection of HI large scale structure out to z=0.15. In this cross correlation, the HI in ALL galaxies contributes, not only the bright ones, which significantly boosts the sensitivity.

  20. The potential of 2D Kalman filtering for soil moisture data assimilation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We examine the potential for parameterizing a two-dimensional (2D) land data assimilation system using spatial error auto-correlation statistics gleaned from a triple collocation analysis and the triplet of: (1) active microwave-, (2) passive microwave- and (3) land surface model-based surface soil ...

  1. Antibody-NKG2D Ligand (Rae-1Beta) Fusion Protein for Breast Cancer Therapy

    DTIC Science & Technology

    2005-08-01

    IgG3) is included for L 25 - comparison. ,20- ൜- Non-Reduced Reduced Purified Proteins NKG2D ligand, Rae-113, and to explore the possibility the...significanti correlation tp flMtc(Aini 4) theric hiu of these prelciminacx aicalysc, inidicaite cadiciiintal stcccles webh farce- &-trillirs of wciitien hav

  2. Residual lens effects in 2D mode of auto-stereoscopic lenticular-based switchable 2D/3D displays

    NASA Astrophysics Data System (ADS)

    Sluijter, M.; IJzerman, W. L.; de Boer, D. K. G.; de Zwart, S. T.

    2006-04-01

    We discuss residual lens effects in multi-view switchable auto-stereoscopic lenticular-based 2D/3D displays. With the introduction of a switchable lenticular, it is possible to switch between a 2D mode and a 3D mode. The 2D mode displays conventional content, whereas the 3D mode provides the sensation of depth to the viewer. The uniformity of a display in the 2D mode is quantified by the quality parameter modulation depth. In order to reduce the modulation depth in the 2D mode, birefringent lens plates are investigated analytically and numerically, by ray tracing. We can conclude that the modulation depth in the 2D mode can be substantially decreased by using birefringent lens plates with a perfect index match between lens material and lens plate. Birefringent lens plates do not disturb the 3D performance of a switchable 2D/3D display.

  3. Differential CYP 2D6 metabolism alters primaquine pharmacokinetics.

    PubMed

    Potter, Brittney M J; Xie, Lisa H; Vuong, Chau; Zhang, Jing; Zhang, Ping; Duan, Dehui; Luong, Thu-Lan T; Bandara Herath, H M T; Dhammika Nanayakkara, N P; Tekwani, Babu L; Walker, Larry A; Nolan, Christina K; Sciotti, Richard J; Zottig, Victor E; Smith, Philip L; Paris, Robert M; Read, Lisa T; Li, Qigui; Pybus, Brandon S; Sousa, Jason C; Reichard, Gregory A; Marcsisin, Sean R

    2015-04-01

    Primaquine (PQ) metabolism by the cytochrome P450 (CYP) 2D family of enzymes is required for antimalarial activity in both humans (2D6) and mice (2D). Human CYP 2D6 is highly polymorphic, and decreased CYP 2D6 enzyme activity has been linked to decreased PQ antimalarial activity. Despite the importance of CYP 2D metabolism in PQ efficacy, the exact role that these enzymes play in PQ metabolism and pharmacokinetics has not been extensively studied in vivo. In this study, a series of PQ pharmacokinetic experiments were conducted in mice with differential CYP 2D metabolism characteristics, including wild-type (WT), CYP 2D knockout (KO), and humanized CYP 2D6 (KO/knock-in [KO/KI]) mice. Plasma and liver pharmacokinetic profiles from a single PQ dose (20 mg/kg of body weight) differed significantly among the strains for PQ and carboxy-PQ. Additionally, due to the suspected role of phenolic metabolites in PQ efficacy, these were probed using reference standards. Levels of phenolic metabolites were highest in mice capable of metabolizing CYP 2D6 substrates (WT and KO/KI 2D6 mice). PQ phenolic metabolites were present in different quantities in the two strains, illustrating species-specific differences in PQ metabolism between the human and mouse enzymes. Taking the data together, this report furthers understanding of PQ pharmacokinetics in the context of differential CYP 2D metabolism and has important implications for PQ administration in humans with different levels of CYP 2D6 enzyme activity.

  4. Mechanical characterization of 2D, 2D stitched, and 3D braided/RTM materials

    NASA Technical Reports Server (NTRS)

    Deaton, Jerry W.; Kullerd, Susan M.; Portanova, Marc A.

    1993-01-01

    Braided composite materials have potential for application in aircraft structures. Fuselage frames, floor beams, wing spars, and stiffeners are examples where braided composites could find application if cost effective processing and damage tolerance requirements are met. Another important consideration for braided composites relates to their mechanical properties and how they compare to the properties of composites produced by other textile composite processes being proposed for these applications. Unfortunately, mechanical property data for braided composites do not appear extensively in the literature. Data are presented in this paper on the mechanical characterization of 2D triaxial braid, 2D triaxial braid plus stitching, and 3D (through-the-thickness) braid composite materials. The braided preforms all had the same graphite tow size and the same nominal braid architectures, (+/- 30 deg/0 deg), and were resin transfer molded (RTM) using the same mold for each of two different resin systems. Static data are presented for notched and unnotched tension, notched and unnotched compression, and compression after impact strengths at room temperature. In addition, some static results, after environmental conditioning, are included. Baseline tension and compression fatigue results are also presented, but only for the 3D braided composite material with one of the resin systems.

  5. Broadband 2D electronic spectrometer using white light and pulse shaping: noise and signal evaluation at 1 and 100 kHz.

    PubMed

    Kearns, Nicholas M; Mehlenbacher, Randy D; Jones, Andrew C; Zanni, Martin T

    2017-04-03

    We have developed a broad bandwidth two-dimensional electronic spectrometer that operates shot-to-shot at repetition rates up to 100 kHz using an acousto-optic pulse shaper. It is called a two-dimensional white-light (2D-WL) spectrometer because the input is white-light supercontinuum. Methods for 100 kHz data collection are studied to understand how laser noise is incorporated into 2D spectra during measurement. At 100 kHz, shot-to-shot scanning of the delays and phases of the pulses in the pulse sequence produces a 2D spectrum 13-times faster and with the same signal-to-noise as using mechanical stages and a chopper. Comparing 100 to 1 kHz repetition rates, data acquisition time is decreased by a factor of 200, which is beyond the improvement expected by the repetition rates alone due to reduction in 1/f noise. These improvements arise because shot-to-shot readout and modulation of the pulse train at 100 kHz enables the electronic coherences to be measured faster than the decay in correlation between laser intensities. Using white light supercontinuum for the pump and probe pulses produces high signal-to-noise spectra on samples with optical densities <0.1 within a few minutes of averaging and an instrument response time of <46 fs thereby demonstrating that that simple broadband continuum sources, although weak, are sufficient to create high quality 2D spectra with >200 nm bandwidth.

  6. Cytochrome P450 2D6 Activity Predicts Discontinuation of Tamoxifen Therapy in Breast Cancer Patients

    PubMed Central

    Rae, James M.; Sikora, Matthew J.; Henry, N. Lynn; Li, Lang; Kim, Seongho; Oesterreich, Steffi; Skaar, Todd; Nguyen, Anne T.; Desta, Zeruesenay; Storniolo, Anna Maria; Flockhart, David A.; Hayes, Daniel F.; Stearns, Vered

    2009-01-01

    The selective estrogen receptor modulator tamoxifen is routinely used for treatment and prevention of estrogen receptor positive breast cancer. Studies of tamoxifen adherence suggest that over half of patients discontinue treatment before the recommended 5 years. We hypothesized that polymorphisms in CYP2D6, the enzyme responsible for tamoxifen activation, predict for tamoxifen discontinuation. Tamoxifen-treated women (n = 297) were genotyped for CYP2D6 variants and assigned a “score” based on predicted allele activities from 0 (no activity) to 2 (high activity). Correlation between CYP2D6 score and discontinuation rates at 4 months were tested. We observed a strong non-linear correlation between higher CYP2D6 score and increased rates of discontinuation (r2 = 0.935, p = 0.018). These data suggest that presence of active CYP2D6 alleles may predict for higher likelihood of tamoxifen discontinuation. Therefore, patients who may be most likely to benefit from tamoxifen may paradoxically be most likely to discontinue treatment prematurely. PMID:19421167

  7. Genetic polymorphism of CYP2D6 in patients with systemic lupus erythematosus and systemic sclerosis.

    PubMed

    Barańska, Małgorzata; Rychlik-Sych, Mariola; Kaszuba, Andrzej; Dziankowska-Bartkowiak, Bożena; Skrętkowicz, Jadwiga; Waszczykowska, Elżbieta

    2016-01-20

    Human organism is constantly exposed to harmful exogenous factors (xenobiotics) including drugs and carcinogenic compounds that can induce development of a large number of diseases. The processes of biotransformation in the organism are multidirectional and xenobiotics can be transformed into active or inactive metabolites via the oxidative route. The knowledge of oxidation polymorphism in the course of systemic lupus erythematosus and systemic sclerosis may be helpful in choosing more efficient and safer therapy, particularly in the case of a disease involving various organs and treated with drugs belonging to diverse therapeutic groups. The aim of the study was to evaluate the CYP2D6 polymorphism in the SLE (systemic lupus erythematosus) and SSc (systemic sclerosis) patients and to investigate a possible correlation with disease susceptibility. The study was carried out in 296 patients: 65 patients with SLE, 81 patients with SSc, and 150 healthy volunteers. The CYP2D6 genotypes were analyzed by polymerase chain reaction fragment length polymorphism (PCR-RFLP) method. The relative risk of developing SSc, expressed by the odds ratio, was three-fold higher for persons with the CYP2D6*1/CYP2D6*4 genotype (OR = 2.9; statistically significant difference, p = 0.0002). A statistically significant correlation between the CYP2D6*4 allele prevalence and the risk for developing SSc was found (OR = 1.53; p = 0.047). No effect of the CYP2D6 gene mutations on the incidence of SLE was noted. The obtained results may suggest the influence of CYP2D6*4 gene variants alleles on increased incidence of systemic sclerosis.

  8. 2D-ELDOR using full S(c-) fitting and absorption lineshapes.

    PubMed

    Chiang, Yun-Wei; Costa-Filho, Antonio; Freed, Jack H

    2007-10-01

    Recent progress in developing 2D-ELDOR (2D electron-electron double resonance) techniques to better capture molecular dynamics in complex fluids, particularly in model and biological membranes, is reported. The new "full S(c-) method", which corrects the spectral analysis for the phase distortion effects present in the experiments, is demonstrated to enhance the sensitivity of 2D-ELDOR in reporting on molecular dynamics in complex membrane environments. That is, instead of performing spectral fitting in the magnitude mode, our new method enables simultaneous fitting of both the real and imaginary components of the S(c-) signal. The full S(c-) fitting not only corrects the phase distortions in the experimental data but also more accurately determines instrumental dead times. The phase corrections applied to the S(c-) spectrum enable the extraction of the pure absorption-mode spectrum, which is characterized by much better resolution than the magnitude-mode spectrum. In the absorption mode, the variation of homogeneous broadening, which reports on the dynamics of the spin probe, can even be observed by visual inspection. This new method is illustrated with results from model membranes of dipalmitoyl-sn-glycero-phosphatidylcholine (DPPC)-cholesterol binary mixtures, as well as with results from plasma membrane vesicles of mast cells. In addition to the dynamic parameters, which provide quantitative descriptions for membranes at the molecular level, the high-resolution absorption spectra themselves may be used as a "fingerprint" to characterize membrane phases and distinguish coexisting components in biomembranes. Thus we find that 2D-ELDOR is greatly improved with the new "full S(c-) method" especially for exploring the complexity of model and biological membranes.

  9. 2D-ELDOR using full Sc- fitting and absorption lineshapes

    NASA Astrophysics Data System (ADS)

    Chiang, Yun-Wei; Costa-Filho, Antonio; Freed, Jack H.

    2007-10-01

    Recent progress in developing 2D-ELDOR (2D electron-electron double resonance) techniques to better capture molecular dynamics in complex fluids, particularly in model and biological membranes, is reported. The new "full Sc- method", which corrects the spectral analysis for the phase distortion effects present in the experiments, is demonstrated to enhance the sensitivity of 2D-ELDOR in reporting on molecular dynamics in complex membrane environments. That is, instead of performing spectral fitting in the magnitude mode, our new method enables simultaneous fitting of both the real and imaginary components of the Sc- signal. The full Sc- fitting not only corrects the phase distortions in the experimental data but also more accurately determines instrumental dead times. The phase corrections applied to the Sc- spectrum enable the extraction of the pure absorption-mode spectrum, which is characterized by much better resolution than the magnitude-mode spectrum. In the absorption mode, the variation of homogeneous broadening, which reports on the dynamics of the spin probe, can even be observed by visual inspection. This new method is illustrated with results from model membranes of dipalmitoyl-sn-glycero-phosphatidylcholine (DPPC)-cholesterol binary mixtures, as well as with results from plasma membrane vesicles of mast cells. In addition to the dynamic parameters, which provide quantitative descriptions for membranes at the molecular level, the high-resolution absorption spectra themselves may be used as a "fingerprint" to characterize membrane phases and distinguish coexisting components in biomembranes. Thus we find that 2D-ELDOR is greatly improved with the new "full Sc- method" especially for exploring the complexity of model and biological membranes.

  10. 2D/3D Visual Tracker for Rover Mast

    NASA Technical Reports Server (NTRS)

    Bajracharya, Max; Madison, Richard W.; Nesnas, Issa A.; Bandari, Esfandiar; Kunz, Clayton; Deans, Matt; Bualat, Maria

    2006-01-01

    A visual-tracker computer program controls an articulated mast on a Mars rover to keep a designated feature (a target) in view while the rover drives toward the target, avoiding obstacles. Several prior visual-tracker programs have been tested on rover platforms; most require very small and well-estimated motion between consecutive image frames a requirement that is not realistic for a rover on rough terrain. The present visual-tracker program is designed to handle large image motions that lead to significant changes in feature geometry and photometry between frames. When a point is selected in one of the images acquired from stereoscopic cameras on the mast, a stereo triangulation algorithm computes a three-dimensional (3D) location for the target. As the rover moves, its body-mounted cameras feed images to a visual-odometry algorithm, which tracks two-dimensional (2D) corner features and computes their old and new 3D locations. The algorithm rejects points, the 3D motions of which are inconsistent with a rigid-world constraint, and then computes the apparent change in the rover pose (i.e., translation and rotation). The mast pan and tilt angles needed to keep the target centered in the field-of-view of the cameras (thereby minimizing the area over which the 2D-tracking algorithm must operate) are computed from the estimated change in the rover pose, the 3D position of the target feature, and a model of kinematics of the mast. If the motion between the consecutive frames is still large (i.e., 3D tracking was unsuccessful), an adaptive view-based matching technique is applied to the new image. This technique uses correlation-based template matching, in which a feature template is scaled by the ratio between the depth in the original template and the depth of pixels in the new image. This is repeated over the entire search window and the best correlation results indicate the appropriate match. The program could be a core for building application programs for systems

  11. Computational Screening of 2D Materials for Photocatalysis.

    PubMed

    Singh, Arunima K; Mathew, Kiran; Zhuang, Houlong L; Hennig, Richard G

    2015-03-19

    Two-dimensional (2D) materials exhibit a range of extraordinary electronic, optical, and mechanical properties different from their bulk counterparts with potential applications for 2D materials emerging in energy storage and conversion technologies. In this Perspective, we summarize the recent developments in the field of solar water splitting using 2D materials and review a computational screening approach to rapidly and efficiently discover more 2D materials that possess properties suitable for solar water splitting. Computational tools based on density-functional theory can predict the intrinsic properties of potential photocatalyst such as their electronic properties, optical absorbance, and solubility in aqueous solutions. Computational tools enable the exploration of possible routes to enhance the photocatalytic activity of 2D materials by use of mechanical strain, bias potential, doping, and pH. We discuss future research directions and needed method developments for the computational design and optimization of 2D materials for photocatalysis.

  12. Force Fluctuations in a 2D Granular Drag Experiment

    NASA Astrophysics Data System (ADS)

    Geng, Junfei; Behringer, R. P.

    2002-11-01

    We study fluctuations in the drag force experienced by an object slowly moving through a 2D granular material consisting of bidisperse disks. Slow drag experiments provide a useful way to understand the nature of stress propagation, fluctuations, and slow dynamics in granular materials. Unlike in a liquid, the drag force in a granular material is largely due to the resistance of inhomogeneous and anisotropic ``force chains'', and thus exhibits strong fluctuations. Experiments were carried out in an apparatus similar in spirit to the one by Albert et al.(R. Albert, M.A. Pfeifer, A.L. Barabasi and P. Schiffer, Phys. Rev. Lett. 82), 205 (1999). and we varied the rotation rate (ω=6.3× 10-6 ˜ 8.7× 10-4Hz), the object size (0.744, 0.876, 1.250,1.610,1.930 cm), and the packing fraction of the system. We observed a weak dependence of the mean force on the medium velocity, a rate-invariant power spectrum decaying as ω-2 for large ω (a remarkable resemblance to results by Miller et al.(B. Miller, C. O'Hern and R.P. Behringer, Phys. Rev. Lett. 77), 3110 (1996).), an exponential distribution of avalanche sizes, and a well defined ``Stress Chain Force Constant''. We also show that a simple model adapted after Kahng. et al.(B. Kahng, I. Albert, P. Schiffer and A.L. Barabasi, Phys. Rev. E. 64), 051303 (2001). reproduces many of experimental observations.

  13. Synthetic Covalent and Non-Covalent 2D Materials.

    PubMed

    Boott, Charlotte E; Nazemi, Ali; Manners, Ian

    2015-11-16

    The creation of synthetic 2D materials represents an attractive challenge that is ultimately driven by their prospective uses in, for example, electronics, biomedicine, catalysis, sensing, and as membranes for separation and filtration. This Review illustrates some recent advances in this diverse field with a focus on covalent and non-covalent 2D polymers and frameworks, and self-assembled 2D materials derived from nanoparticles, homopolymers, and block copolymers.

  14. Cytochrome P450 2D6 variants in a Caucasian population: Allele frequencies and phenotypic consequences

    SciTech Connect

    Sachse, C.; Brockmoeller, J.; Bauer, S.; Roots, I.

    1997-02-01

    Cytochrome P450 2D6 (CYP2D6) metabolizes many important drugs. CYP2D6 activity ranges from complete deficiency to ultrafast metabolism, depending on at least 16 different known alleles. Their frequencies were determined in 589 unrelated German volunteers and correlated with enzyme activity measured by phenotyping with dextromethorphan or debrisoquine. For genotyping, nested PCR-RFLP tests from a PCR amplificate of the entire CYP2D6 gene were developed. The frequency of the CYP2D6*1 allele coding for extensive metabolizer (EM) phenotype was .364. The alleles coding for slightly (CYP2D6*2) or moderately (*9 and *10) reduced activity (intermediate metabolizer phenotype [IM]) showed frequencies of .324, .018, and .015, respectively. By use of novel PCR tests for discrimination, CYP2D6 gene duplication alleles were found with frequencies of.005 (*1 x 2), .013 (* 2 x 2), and .001 (*4 x 2). Frequencies of alleles with complete deficiency (poor metabolizer phenotype [PM]) were .207 (*4), .020 (*3 and *5), .009 (*6), and .001 (*7, *15, and *16). The defective CYP2D6 alleles *8, *11, *12, *13, and *14 were not found. All 41 PMs (7.0%) in this sample were explained by five mutations detected by four PCR-RFLP tests, which may suffice, together with the gene duplication test, for clinical prediction of CYP2D6 capacity. Three novel variants of known CYP2D6 alleles were discovered: *1C (T{sub 1957}C), *2B (additional C{sub 2558}T), and *4E (additional C{sub 2938}T). Analysis of variance showed significant differences in enzymatic activity measured by the dextromethorphan metabolic ratio (MR) between carriers of EN/PM (mean MR = .006) and IM/PM (mean MR = .014) alleles and between carriers of one (mean MR = .009) and two (mean MR = .003) functional alleles. The results of this study provide a solid basis for prediction of CYP2D6 capacity, as required in drug research and routine drug treatment. 35 refs., 4 figs., 5 tabs.

  15. Multitaper Spectrum Estimates

    NASA Astrophysics Data System (ADS)

    Fodor, I. K.; Stark, P. B.

    Multitapering is a statistical technique developed to improve on the notorious periodogram estimate of the power spectrum (Thomson, 1982; Percival, Walden 1993). We show how to obtain orthogonal tapers for time series observed with gaps, and how to use statistical resampling techniques (Efron, Tibshirani 1993) to calculate realistic uncertainty estimates for multitaper estimates. We introduce multisegment multitapering. Multitapering can also be extended to the 2D case. We indicate how to construct tapers that minimize the spatial leakage in estimates of the spherical harmonic decomposition of the velocity images. Spatial multitapering followed by the temporal tapering of the estimated spherical harmonic time series is expected to result in improved spectrum and subsequent solar oscillation mode parameter estimates.

  16. A critical review of the research on the extreme male brain theory and digit ratio (2D:4D).

    PubMed

    Teatero, Missy L; Netley, Charles

    2013-11-01

    Boys are more likely than girls to be diagnosed with an autism spectrum disorder (ASD). The extreme male brain (EMB) theory of ASD suggests that fetal testosterone (FT) exposure may underlie sex differences in autistic traits. A link between the organizational effects of FT on the brain and ASD is often drawn based on research using digit ratio (2D:4D), a putative biomarker, without a full survey of the findings. This paper critically and quantitatively reviews the research on the relationship between 2D:4D and ASD as well as autism spectrum, empathizing, and systemizing measures in neurotypical populations. Overall, there is some support for the EMB theory in all four areas, particularly the 2D:4D-ASD relationship. Recommendations for future research are provided.

  17. Epitaxial 2D SnSe2/ 2D WSe2 van der Waals Heterostructures.

    PubMed

    Aretouli, Kleopatra Emmanouil; Tsoutsou, Dimitra; Tsipas, Polychronis; Marquez-Velasco, Jose; Aminalragia Giamini, Sigiava; Kelaidis, Nicolaos; Psycharis, Vassilis; Dimoulas, Athanasios

    2016-09-07

    van der Waals heterostructures of 2D semiconductor materials can be used to realize a number of (opto)electronic devices including tunneling field effect devices (TFETs). It is shown in this work that high quality SnSe2/WSe2 vdW heterostructure can be grown by molecular beam epitaxy on AlN(0001)/Si(111) substrates using a Bi2Se3 buffer layer. A valence band offset of 0.8 eV matches the energy gap of SnSe2 in such a way that the VB edge of WSe2 and the CB edge of SnSe2 are lined up, making this materials combination suitable for (nearly) broken gap TFETs.

  18. Evaluation of gas radiation heat transfer in a 2D axisymmetric geometry using the line-by-line integration and WSGG models

    NASA Astrophysics Data System (ADS)

    Centeno, Felipe Roman; Brittes, Rogério; França, Francis. H. R.; Ezekoye, Ofodike A.

    2015-05-01

    The weighted-sum-of-gray-gases (WSGG) model is widely used in engineering computations of radiative heat transfer due to its relative simplicity, robustness and flexibility. This paper presents the computation of radiative heat transfer in a 2D axisymmetric chamber using two WSGG models to compute radiation in H2O and CO2 mixtures. The first model considers a fixed ratio between the molar concentrations of H2O and CO2, while the second allows the solution for arbitrary ratios. The correlations for both models are based on the HITEMP2010 database. The test case considers typical conditions found in turbulent methane flames, with steep variations in the temperature field as well as in the molar concentrations of the participating species. To assess the accuracy of the WSGG model, the results are compared with a solution obtained by line-by-line integration (LBL) of the spectrum.

  19. Duality Between Spin Networks and the 2D Ising Model

    NASA Astrophysics Data System (ADS)

    Bonzom, Valentin; Costantino, Francesco; Livine, Etera R.

    2016-06-01

    The goal of this paper is to exhibit a deep relation between the partition function of the Ising model on a planar trivalent graph and the generating series of the spin network evaluations on the same graph. We provide respectively a fermionic and a bosonic Gaussian integral formulation for each of these functions and we show that they are the inverse of each other (up to some explicit constants) by exhibiting a supersymmetry relating the two formulations. We investigate three aspects and applications of this duality. First, we propose higher order supersymmetric theories that couple the geometry of the spin networks to the Ising model and for which supersymmetric localization still holds. Secondly, after interpreting the generating function of spin network evaluations as the projection of a coherent state of loop quantum gravity onto the flat connection state, we find the probability distribution induced by that coherent state on the edge spins and study its stationary phase approximation. It is found that the stationary points correspond to the critical values of the couplings of the 2D Ising model, at least for isoradial graphs. Third, we analyze the mapping of the correlations of the Ising model to spin network observables, and describe the phase transition on those observables on the hexagonal lattice. This opens the door to many new possibilities, especially for the study of the coarse-graining and continuum limit of spin networks in the context of quantum gravity.

  20. Ab initio modeling of 2D layered organohalide lead perovskites

    NASA Astrophysics Data System (ADS)

    Fraccarollo, Alberto; Cantatore, Valentina; Boschetto, Gabriele; Marchese, Leonardo; Cossi, Maurizio

    2016-04-01

    A number of 2D layered perovskites A2PbI4 and BPbI4, with A and B mono- and divalent ammonium and imidazolium cations, have been modeled with different theoretical methods. The periodic structures have been optimized (both in monoclinic and in triclinic systems, corresponding to eclipsed and staggered arrangements of the inorganic layers) at the DFT level, with hybrid functionals, Gaussian-type orbitals and dispersion energy corrections. With the same methods, the various contributions to the solid stabilization energy have been discussed, separating electrostatic and dispersion energies, organic-organic intralayer interactions and H-bonding effects, when applicable. Then the electronic band gaps have been computed with plane waves, at the DFT level with scalar and full relativistic potentials, and including the correlation energy through the GW approximation. Spin orbit coupling and GW effects have been combined in an additive scheme, validated by comparing the computed gap with well known experimental and theoretical results for a model system. Finally, various contributions to the computed band gaps have been discussed on some of the studied systems, by varying some geometrical parameters and by substituting one cation in another's place.

  1. Circular photogalvanic effect caused by the transitions between edge and 2D states in a 2D topological insulator

    NASA Astrophysics Data System (ADS)

    Magarill, L. I.; Entin, M. V.

    2016-12-01

    The electron absorption and the edge photocurrent of a 2D topological insulator are studied for transitions between edge states to 2D states. The circular polarized light is found to produce the edge photocurrent, the direction of which is determined by light polarization and edge orientation. It is shown that the edge-state current is found to exceed the 2D current owing to the topological protection of the edge states.

  2. Comparison of 2-D and 3-D estimates of placental volume in early pregnancy.

    PubMed

    Aye, Christina Y L; Stevenson, Gordon N; Impey, Lawrence; Collins, Sally L

    2015-03-01

    Ultrasound estimation of placental volume (PlaV) between 11 and 13 wk has been proposed as part of a screening test for small-for-gestational-age babies. A semi-automated 3-D technique, validated against the gold standard of manual delineation, has been found at this stage of gestation to predict small-for-gestational-age at term. Recently, when used in the third trimester, an estimate obtained using a 2-D technique was found to correlate with placental weight at delivery. Given its greater simplicity, the 2-D technique might be more useful as part of an early screening test. We investigated if the two techniques produced similar results when used in the first trimester. The correlation between PlaV values calculated by the two different techniques was assessed in 139 first-trimester placentas. The agreement on PlaV and derived "standardized placental volume," a dimensionless index correcting for gestational age, was explored with the Mann-Whitney test and Bland-Altman plots. Placentas were categorized into five different shape subtypes, and a subgroup analysis was performed. Agreement was poor for both PlaV and standardized PlaV (p < 0.001 and p < 0.001), with the 2-D technique yielding larger estimates for both indices compared with the 3-D method. The mean difference in standardized PlaV values between the two methods was 0.007 (95% confidence interval: 0.006-0.009). The best agreement was found for regular rectangle-shaped placentas (p = 0.438 and p = 0.408). The poor correlation between the 2-D and 3-D techniques may result from the heterogeneity of placental morphology at this stage of gestation. In early gestation, the simpler 2-D estimates of PlaV do not correlate strongly with those obtained with the validated 3-D technique.

  3. A Novel 2-D OFDM-DS-CDMA Receiver with Frequency-Time Spreading

    NASA Astrophysics Data System (ADS)

    Chen, Joy Iong-Zong

    This paper presents a novel 2-D (2-dimension) receiver that adopts the reception scheme to promote OFDM-DS-CDMA (orthogonal frequency division multiplexing multi-carrier coded-division multiple-access) system performance. The system model includes spread coding and a system block diagram of the 2-D receiver shown graphically with 3-D (three dimensions) plots. The analytical calculation of system performance for an OFDM-DS-CDMA system combined with the proposed receiver equipment is investigated. To evaluate the results from the channel fading effect is considered over the correlated fading environments. The correlated-Nakagami-m statistical distribution is taken into account in the evaluation. The results show that the number of users, the number of subcarriers and the fading channel correlation generally affect OFDM-DS-CDMA systems. The system is also influenced by the Doppler shift and the signal propagation environment (fading parameter).

  4. A Fast Algorithm for 2D DOA Estimation Using an Omnidirectional Sensor Array.

    PubMed

    Nie, Weike; Xu, Kaijie; Feng, Dazheng; Wu, Chase Qishi; Hou, Aiqin; Yin, Xiaoyan

    2017-03-04

    The traditional 2D MUSIC algorithm fixes the azimuth or the elevation, and searches for the other without considering the directions of sources. A spectrum peak diffusion effect phenomenon is observed and may be utilized to detect the approximate directions of sources. Accordingly, a fast 2D MUSIC algorithm, which performs azimuth and elevation simultaneous searches (henceforth referred to as AESS) based on only three rounds of search is proposed. Firstly, AESS searches along a circle to detect the approximate source directions. Then, a subsequent search is launched along several straight lines based on these approximate directions. Finally, the 2D Direction of Arrival (DOA) of each source is derived by searching on several small concentric circles. Unlike the 2D MUSIC algorithm, AESS does not fix any azimuth and elevation parameters. Instead, the adjacent point of each search possesses different azimuth and elevation, i.e., azimuth and elevation are simultaneously searched to ensure that the search path is minimized, and hence the total spectral search over the angular field of view is avoided. Simulation results demonstrate the performance characters of the proposed AESS over some existing algorithms.

  5. A Fast Algorithm for 2D DOA Estimation Using an Omnidirectional Sensor Array

    PubMed Central

    Nie, Weike; Xu, Kaijie; Feng, Dazheng; Wu, Chase Qishi; Hou, Aiqin; Yin, Xiaoyan

    2017-01-01

    The traditional 2D MUSIC algorithm fixes the azimuth or the elevation, and searches for the other without considering the directions of sources. A spectrum peak diffusion effect phenomenon is observed and may be utilized to detect the approximate directions of sources. Accordingly, a fast 2D MUSIC algorithm, which performs azimuth and elevation simultaneous searches (henceforth referred to as AESS) based on only three rounds of search is proposed. Firstly, AESS searches along a circle to detect the approximate source directions. Then, a subsequent search is launched along several straight lines based on these approximate directions. Finally, the 2D Direction of Arrival (DOA) of each source is derived by searching on several small concentric circles. Unlike the 2D MUSIC algorithm, AESS does not fix any azimuth and elevation parameters. Instead, the adjacent point of each search possesses different azimuth and elevation, i.e., azimuth and elevation are simultaneously searched to ensure that the search path is minimized, and hence the total spectral search over the angular field of view is avoided. Simulation results demonstrate the performance characters of the proposed AESS over some existing algorithms. PMID:28273851

  6. Application of two-dimensional near-infrared correlation spectroscopy to the discrimination of Chinese herbal medicine of different geographic regions

    NASA Astrophysics Data System (ADS)

    Lu, Jun; Xiang, Bingren; Liu, Hao; Xiang, Suyun; Xie, Shaofei; Deng, Haishan

    2008-02-01

    Fructus Lycii is a traditional Chinese medicinal herb. The objective of this paper was to apply two-dimensional (2D) near-infrared (NIR) correlation spectroscopy to the discrimination of Fructus Lycii of four different geographic regions. Generalized 2D-NIR correlation spectroscopy was able to enhance spectral resolution, simplify the spectrum with overlapped bands, and provide information about temperature-induced spectral intensity variations that was hard to obtain from one-dimensional NIR spectroscopy. The 2D synchronous and asynchronous spectra showed remarkable differences within the range of 4950-5700 cm -1 between samples of different geographic regions. Using NIR instead of IR made the 2D approach more convenient and fast, and it can be applied to more area like process control. This approach can also be applied analogously to the discrimination of other Chinese herbal medicine of different geographic regions.

  7. Integrating Mobile Multimedia into Textbooks: 2D Barcodes

    ERIC Educational Resources Information Center

    Uluyol, Celebi; Agca, R. Kagan

    2012-01-01

    The major goal of this study was to empirically compare text-plus-mobile phone learning using an integrated 2D barcode tag in a printed text with three other conditions described in multimedia learning theory. The method examined in the study involved modifications of the instructional material such that: a 2D barcode was used near the text, the…

  8. Efficient Visible Quasi-2D Perovskite Light-Emitting Diodes.

    PubMed

    Byun, Jinwoo; Cho, Himchan; Wolf, Christoph; Jang, Mi; Sadhanala, Aditya; Friend, Richard H; Yang, Hoichang; Lee, Tae-Woo

    2016-09-01

    Efficient quasi-2D-structure perovskite light-emitting diodes (4.90 cd A(-1) ) are demonstrated by mixing a 3D-structured perovskite material (methyl ammonium lead bromide) and a 2D-structured perovskite material (phenylethyl ammonium lead bromide), which can be ascribed to better film uniformity, enhanced exciton confinement, and reduced trap density.

  9. Adaptation algorithms for 2-D feedforward neural networks.

    PubMed

    Kaczorek, T

    1995-01-01

    The generalized weight adaptation algorithms presented by J.G. Kuschewski et al. (1993) and by S.H. Zak and H.J. Sira-Ramirez (1990) are extended for 2-D madaline and 2-D two-layer feedforward neural nets (FNNs).

  10. The strength of heterogeneous volcanic rocks: A 2D approximation

    NASA Astrophysics Data System (ADS)

    Heap, Michael J.; Wadsworth, Fabian B.; Xu, Tao; Chen, Chong-feng; Tang, Chun'an

    2016-06-01

    that published experimental data (for which the porosity and crystal fraction is known) correlate well with our modelled curves, adding validity to our approach. We present herein a 2D analytical tool to estimate the strength of volcanic rock that can be used when the porosity, crystal fraction, and maximum pore diameter are known.

  11. Regulation of ligands for the NKG2D activating receptor

    PubMed Central

    Raulet, David H.; Gasser, Stephan; Gowen, Benjamin G.; Deng, Weiwen; Jung, Heiyoun

    2014-01-01

    NKG2D is an activating receptor expressed by all NK cells and subsets of T cells. It serves as a major recognition receptor for detection and elimination of transformed and infected cells and participates in the genesis of several inflammatory diseases. The ligands for NKG2D are self-proteins that are induced by pathways that are active in certain pathophysiological states. NKG2D ligands are regulated transcriptionally, at the level of mRNA and protein stability, and by cleavage from the cell surface. In some cases, ligand induction can be attributed to pathways that are activated specifically in cancer cells or infected cells. We review the numerous pathways that have been implicated in the regulation of NKG2D ligands, discuss the pathologic states in which those pathways are likely to act, and attempt to synthesize the findings into general schemes of NKG2D ligand regulation in NK cell responses to cancer and infection. PMID:23298206

  12. 2D materials and van der Waals heterostructures.

    PubMed

    Novoselov, K S; Mishchenko, A; Carvalho, A; Castro Neto, A H

    2016-07-29

    The physics of two-dimensional (2D) materials and heterostructures based on such crystals has been developing extremely fast. With these new materials, truly 2D physics has begun to appear (for instance, the absence of long-range order, 2D excitons, commensurate-incommensurate transition, etc.). Novel heterostructure devices--such as tunneling transistors, resonant tunneling diodes, and light-emitting diodes--are also starting to emerge. Composed from individual 2D crystals, such devices use the properties of those materials to create functionalities that are not accessible in other heterostructures. Here we review the properties of novel 2D crystals and examine how their properties are used in new heterostructure devices.

  13. New generation transistor technologies enabled by 2D crystals

    NASA Astrophysics Data System (ADS)

    Jena, D.

    2013-05-01

    The discovery of graphene opened the door to 2D crystal materials. The lack of a bandgap in 2D graphene makes it unsuitable for electronic switching transistors in the conventional field-effect sense, though possible techniques exploiting the unique bandstructure and nanostructures are being explored. The transition metal dichalcogenides have 2D crystal semiconductors, which are well-suited for electronic switching. We experimentally demonstrate field effect transistors with current saturation and carrier inversion made from layered 2D crystal semiconductors such as MoS2, WS2, and the related family. We also evaluate the feasibility of such semiconducting 2D crystals for tunneling field effect transistors for low-power digital logic. The article summarizes the current state of new generation transistor technologies either proposed, or demonstrated, with a commentary on the challenges and prospects moving forward.

  14. Calcium-dependent activation and autolysis of Arabidopsis metacaspase 2d.

    PubMed

    Watanabe, Naohide; Lam, Eric

    2011-03-25

    Metacaspases (MCPs) are members of a new family of cysteine proteases found in plants, fungi, and protozoa that are structurally related to metazoan caspases. Recent studies showed that plant MCPs are arginine/lysine-specific cysteine proteases with caspase-like processing activities in vitro and in vivo, and some of the plant type II MCPs exhibit Ca(2+) dependence for their endopeptidase activity in vitro. However, the mechanisms and biological relevance of Ca(2+) dependence and self-processing of plant MCPs remains unclear. Here we show that recombinant AtMCP2d, the most abundantly expressed member of Arabidopsis type II MCPs at the transcriptional level, exhibits a strict Ca(2+) dependence for its catalytic activation that is apparently mediated by intramolecular self-cleavage mechanism. However, rapid inactivation of AtMCP2d activity concomitant with Ca(2+)-induced self-processing at multiple internal sites was observed. Because active AtMCP2d can cleave its inactive form, intermolecular cleavage (autolysis) of AtMCP2d could also occur under our assay conditions. Ca(2+)-induced self-processing of recombinant AtMCP2d was found to correlate with the sequential appearance of at least six intermediates, including self-cleaved forms, during the proenzyme purification process. Six of these peptides were characterized, and the cleavage sites were mapped through N-terminal protein sequencing. Mutation analysis of AtMCP2d revealed that cleavage after Lys-225, which is a highly conserved residue among the six Arabidopsis type II MCPs, is critical for the catalytic activation by Ca(2+), and we demonstrate that this residue is essential for AtMCP2d activation of H(2)O(2)-induced cell death in yeast. Together, our results provide clues to understand the mode of regulation for this class of proteases.

  15. Estrogen-Induced Cholestasis Leads to Repressed CYP2D6 Expression in CYP2D6-Humanized Mice.

    PubMed

    Pan, Xian; Jeong, Hyunyoung

    2015-07-01

    Cholestasis activates bile acid receptor farnesoid X receptor (FXR) and subsequently enhances hepatic expression of small heterodimer partner (SHP). We previously demonstrated that SHP represses the transactivation of cytochrome P450 2D6 (CYP2D6) promoter by hepatocyte nuclear factor (HNF) 4α. In this study, we investigated the effects of estrogen-induced cholestasis on CYP2D6 expression. Estrogen-induced cholestasis occurs in subjects receiving estrogen for contraception or hormone replacement, or in susceptible women during pregnancy. In CYP2D6-humanized transgenic (Tg-CYP2D6) mice, cholestasis triggered by administration of 17α-ethinylestradiol (EE2) at a high dose led to 2- to 3-fold decreases in CYP2D6 expression. This was accompanied by increased hepatic SHP expression and subsequent decreases in the recruitment of HNF4α to CYP2D6 promoter. Interestingly, estrogen-induced cholestasis also led to increased recruitment of estrogen receptor (ER) α, but not that of FXR, to Shp promoter, suggesting a predominant role of ERα in transcriptional regulation of SHP in estrogen-induced cholestasis. EE2 at a low dose (that does not cause cholestasis) also increased SHP (by ∼ 50%) and decreased CYP2D6 expression (by 1.5-fold) in Tg-CYP2D6 mice, the magnitude of differences being much smaller than that shown in EE2-induced cholestasis. Taken together, our data indicate that EE2-induced cholestasis increases SHP and represses CYP2D6 expression in Tg-CYP2D6 mice in part through ERα transactivation of Shp promoter.

  16. Spectrum Recombination.

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    1984-01-01

    Describes several methods of executing lecture demonstrations involving the recombination of the spectrum. Groups the techniques into two general classes: bringing selected portions of the spectrum together using lenses or mirrors and blurring the colors by rapid movement or foreshortening. (JM)

  17. Immunological Visibility: Posttranscriptional Regulation of Human NKG2D Ligands by the EGF Receptor Pathway

    PubMed Central

    Vantourout, Pierre; Willcox, Carrie; Turner, Andrea; Swanson, Chad; Haque, Yasmin; Sobolev, Olga; Grigoriadis, Anita; Tutt, Andrew; Hayday, Adrian

    2014-01-01

    Human cytolytic T lymphocytes and NK cells can limit tumor growth and are being increasingly harnessed for tumor immunotherapy. One way cytolytic lymphocytes recognize tumor cells is by engagement of their activating receptor, NKG2D, by stress-antigens of the MICA/B and ULBP families. This study shows that surface upregulation of NKG2D ligands by human epithelial cells in response to ultraviolet irradiation, osmotic shock, oxidative stress, and growth factor provision, is attributable to activation of the EGF-receptor (EGFR). EGFR activation causes intracellular re-localisation of AUF1 proteins that ordinarily destabilise NKG2D ligand mRNAs by targeting an AU-rich element conserved within the 3′ ends of most human but not murine NKG2D ligand genes. Consistent with these findings, NKG2D ligand expression by primary human carcinomas positively correlated with EGFR expression that is commonly hyper-activated in such tumours, and was reduced by clinical EGFR inhibitors. Thus, stress-induced activation of EGFR not only regulates cell growth but concomitantly regulates the cells’ immunological visibility. Thus, therapeutics designed to limit cancer cell growth should also be considered in terms of their impact on immunosurveillance. PMID:24718859

  18. Soap film as a 2D system: Diffusion and flow fields

    NASA Astrophysics Data System (ADS)

    Vivek, Skanda; Weeks, Eric

    2014-03-01

    We use microrheology to measure the 2D (interfacial) viscosity of soap films. Microrheology uses the diffusivity of tracer particles suspended in the soap film to infer viscosity. Our tracer particles are colloids of diameters d = 0.10 and 0.18 microns. We measure the interfacial viscosity of soap films ranging in thickness from 0.1 to 3 microns. The thickness of these films is measured using the infrared absorbance of the water based soap films. From film thickness, viscosity of the fluid used to make the film and particle diffusivity, we can infer the interfacial viscosity due to the surfactant layers at the film/air interfaces. We find positive constant interfacial viscosities for thin films (h/d < 5), within error. For thicker films, we find negative viscosities, indicating 3D effects begin to play a role, as air stresses become less important. The transition from 2D to 3D properties as a function of h/d is sharp at about h/d=6. Additionally, we measure larger length scale flow fields from correlated particle motions and find good agreement with what is expected from the theory of 2D fluids for all our films. In conclusion, single particle diffusion shows a sharp transition away from 2D like behavior as h/d increases, but the long-range flow fields still act as 2D.

  19. Unveiling Dimensionality Dependence of Glassy Dynamics: 2D Infinite Fluctuation Eclipses Inherent Structural Relaxation.

    PubMed

    Shiba, Hayato; Yamada, Yasunori; Kawasaki, Takeshi; Kim, Kang

    2016-12-09

    By using large-scale molecular dynamics simulations, the dynamics of two-dimensional (2D) supercooled liquids turns out to be dependent on the system size, while the size dependence is not pronounced in three-dimensional (3D) systems. It is demonstrated that the strong system-size effect in 2D amorphous systems originates from the enhanced fluctuations at long wavelengths which are similar to those of 2D crystal phonons. This observation is further supported by the frequency dependence of the vibrational density of states, consisting of the Debye approximation in the low-wave-number limit. However, the system-size effect in the intermediate scattering function becomes negligible when the length scale is larger than the vibrational amplitude. This suggests that the finite-size effect in a 2D system is transient and also that the structural relaxation itself is not fundamentally different from that in a 3D system. In fact, the dynamic correlation lengths estimated from the bond-breakage function, which do not suffer from those enhanced fluctuations, are not size dependent in either 2D or 3D systems.

  20. Single-scan 2D NMR: An Emerging Tool in Analytical Spectroscopy

    PubMed Central

    Giraudeau, Patrick; Frydman, Lucio

    2016-01-01

    Two-dimensional Nuclear Magnetic Resonance (2D NMR) spectroscopy is widely used in chemical and biochemical analyses. Multidimensional NMR is also witnessing an increased use in quantitative and metabolic screening applications. Conventional 2D NMR experiments, however, are affected by inherently long acquisition durations, arising from their need to sample the frequencies involved along their indirect domains in an incremented, scan-by-scan nature. A decade ago a so-called “ultrafast” (UF) approach was proposed, capable to deliver arbitrary 2D NMR spectra involving any kind of homo- or hetero-nuclear correlations, in a single scan. During the intervening years the performance of this sub-second 2D NMR methodology has been greatly improved, and UF 2D NMR is rapidly becoming a powerful analytical tool witnessing an expanded scope of applications. The present reviews summarizes the principles and the main developments which have contributed to the success of this approach, and focuses on applications which have been recently demonstrated in various areas of analytical chemistry –from the real time monitoring of chemical and biochemical processes, to extensions in hyphenated techniques and in quantitative applications. PMID:25014342

  1. Unveiling Dimensionality Dependence of Glassy Dynamics: 2D Infinite Fluctuation Eclipses Inherent Structural Relaxation

    NASA Astrophysics Data System (ADS)

    Shiba, Hayato; Yamada, Yasunori; Kawasaki, Takeshi; Kim, Kang

    2016-12-01

    By using large-scale molecular dynamics simulations, the dynamics of two-dimensional (2D) supercooled liquids turns out to be dependent on the system size, while the size dependence is not pronounced in three-dimensional (3D) systems. It is demonstrated that the strong system-size effect in 2D amorphous systems originates from the enhanced fluctuations at long wavelengths which are similar to those of 2D crystal phonons. This observation is further supported by the frequency dependence of the vibrational density of states, consisting of the Debye approximation in the low-wave-number limit. However, the system-size effect in the intermediate scattering function becomes negligible when the length scale is larger than the vibrational amplitude. This suggests that the finite-size effect in a 2D system is transient and also that the structural relaxation itself is not fundamentally different from that in a 3D system. In fact, the dynamic correlation lengths estimated from the bond-breakage function, which do not suffer from those enhanced fluctuations, are not size dependent in either 2D or 3D systems.

  2. Acute myocarditis with normal wall motion detected with 2D speckle tracking echocardiography

    PubMed Central

    Niel, Johannes; Aichinger, Josef; Ebner, Christian

    2016-01-01

    Summary We present the case of a 26-year-old male with acute tonsillitis who was referred for coronary angiography because of chest pain, elevated cardiac biomarkers, and biphasic T waves. The patient had no cardiovascular risk factors. Echocardiography showed no wall motion abnormalities and no pericardial effusion. 2D speckle tracking revealed distinct decreased regional peak longitudinal systolic strain in the lateral and posterior walls. Ischemic disease was extremely unlikely in view of his young age, negative family history regarding coronary artery disease, and lack of regional wall motion abnormalities on the conventional 2D echocardiogram. Coronary angiography was deferred as myocarditis was suspected. To confirm the diagnosis, cardiac magnetic resonance tomography (MRT) was performed, showing subepicardial delayed hyperenhancement in the lateral and posterior walls correlating closely with the strain pattern obtained by 2D speckle tracking echocardiography. With a working diagnosis of acute myocarditis associated with acute tonsillitis, we prescribed antibiotics and nonsteroidal anti-inflammatory drugs. The patient’s clinical signs resolved along with normalization of serum creatine kinase (CK) levels, and the patient was discharged on the third day after admission. Learning points Acute myocarditis can mimic acute coronary syndromes.Conventional 2D echocardiography lacks specific features for detection of subtle regional wall motion abnormalities.2D speckle tracking expands the scope of echocardiography in identifying myocardial dysfunction derived from edema in acute myocarditis. PMID:27249814

  3. Digit ratio (2D:4D), dominance, reproductive success, asymmetry, and sociosexuality in the BBC Internet Study.

    PubMed

    Manning, John T; Fink, Bernhard

    2008-01-01

    Digit ratio (2D:4D) may be a correlate of prenatal sex steroids, and has been linked to traits, which are influenced by fetal testosterone and estrogen. Here we consider such links in a large Internet study of sex differences (the BBC Internet Study) in which finger lengths were self-measured. Consistent with lab-based findings the 2D:4D in this study shows sexual dimorphism, ethnic differences and higher dimorphism of right 2D:4D than left, thereby indicating that 2D:4D does measure real between-participant variation. High error in self-measurement of fingers reduces effect sizes. However, the large sample size gives assurance that significant effects are likely to be real. We controlled for ethnicity and sexual orientation by considering White heterosexuals only (153,429 participants). Sexual dimorphism was confirmed in 2D:4D and for the difference of right-left 2D:4D. After Bonferroni correction we found highly significant relationships with low effect sizes as follows. In males and females there were negative associations between 2D:4D and dominance. In males there were negative associations between 2D:4D and family size and factors associated with reproductive success. For females these associations were positive. For asymmetry we found U-shaped relationships with 2D:4D in both males and females. We found no relationship between 2D:4D and promiscuity (sociosexuality). In total, we considered 48 relationships and found 29 to be significant. We compare our findings with a similar study reported by Putz et al. (2004), which found only 2 out of 57 correlations to be significant and discuss possible reasons for the discrepancies between the studies.

  4. Targeted fluorescence imaging enhanced by 2D materials: a comparison between 2D MoS2 and graphene oxide.

    PubMed

    Xie, Donghao; Ji, Ding-Kun; Zhang, Yue; Cao, Jun; Zheng, Hu; Liu, Lin; Zang, Yi; Li, Jia; Chen, Guo-Rong; James, Tony D; He, Xiao-Peng

    2016-08-04

    Here we demonstrate that 2D MoS2 can enhance the receptor-targeting and imaging ability of a fluorophore-labelled ligand. The 2D MoS2 has an enhanced working concentration range when compared with graphene oxide, resulting in the improved imaging of both cell and tissue samples.

  5. Quantal Heating of Conducting Electrons with Discrete Spectrum

    SciTech Connect

    Vitkalov, S. A.; Bykov, A. A.

    2011-12-23

    Usually heating of conducting electrons by dc electric field results in an increase of electron temperature. In this paper we show that the dc heating of 2D electrons, placed in quantized magnetic fields, results in a peculiar electron distribution, which has the same broadening or an effective 'temperature' as the unbiased electron system. The quantal heating, however, violates strongly the Ohm's Law. In the conducting system with discrete electron spectrum the quantal heating results in spectacular decrease of electron resistance and transition of the electrons into a state with zero differential resistance (ZDR). Finally the heating leads to apparent dc driven metal-insulator transition, which correlates with the transition into the ZDR state. The correlation is very unexpected and is not understood.

  6. 3D reconstruction of a carotid bifurcation from 2D transversal ultrasound images.

    PubMed

    Yeom, Eunseop; Nam, Kweon-Ho; Jin, Changzhu; Paeng, Dong-Guk; Lee, Sang-Joon

    2014-12-01

    Visualizing and analyzing the morphological structure of carotid bifurcations are important for understanding the etiology of carotid atherosclerosis, which is a major cause of stroke and transient ischemic attack. For delineation of vasculatures in the carotid artery, ultrasound examinations have been widely employed because of a noninvasive procedure without ionizing radiation. However, conventional 2D ultrasound imaging has technical limitations in observing the complicated 3D shapes and asymmetric vasodilation of bifurcations. This study aims to propose image-processing techniques for better 3D reconstruction of a carotid bifurcation in a rat by using 2D cross-sectional ultrasound images. A high-resolution ultrasound imaging system with a probe centered at 40MHz was employed to obtain 2D transversal images. The lumen boundaries in each transverse ultrasound image were detected by using three different techniques; an ellipse-fitting, a correlation mapping to visualize the decorrelation of blood flow, and the ellipse-fitting on the correlation map. When the results are compared, the third technique provides relatively good boundary extraction. The incomplete boundaries of arterial lumen caused by acoustic artifacts are somewhat resolved by adopting the correlation mapping and the distortion in the boundary detection near the bifurcation apex was largely reduced by using the ellipse-fitting technique. The 3D lumen geometry of a carotid artery was obtained by volumetric rendering of several 2D slices. For the 3D vasodilatation of the carotid bifurcation, lumen geometries at the contraction and expansion states were simultaneously depicted at various view angles. The present 3D reconstruction methods would be useful for efficient extraction and construction of the 3D lumen geometries of carotid bifurcations from 2D ultrasound images.

  7. A Convective Vorticity Vector Associated With Tropical Convection: A 2D Cloud-Resolving Modeling Study

    NASA Technical Reports Server (NTRS)

    Gao, Shou-Ting; Ping, Fan; Li, Xiao-Fan; Tao, Wei-Kuo

    2004-01-01

    Although dry/moist potential vorticity is a useful physical quantity for meteorological analysis, it cannot be applied to the analysis of 2D simulations. A convective vorticity vector (CVV) is introduced in this study to analyze 2D cloud-resolving simulation data associated with 2D tropical convection. The cloud model is forced by the vertical velocity, zonal wind, horizontal advection, and sea surface temperature obtained from the TOGA COARE, and is integrated for a selected 10-day period. The CVV has zonal and vertical components in the 2D x-z frame. Analysis of zonally-averaged and mass-integrated quantities shows that the correlation coefficient between the vertical component of the CVV and the sum of the cloud hydrometeor mixing ratios is 0.81, whereas the correlation coefficient between the zonal component and the sum of the mixing ratios is only 0.18. This indicates that the vertical component of the CVV is closely associated with tropical convection. The tendency equation for the vertical component of the CVV is derived and the zonally-averaged and mass-integrated tendency budgets are analyzed. The tendency of the vertical component of the CVV is determined by the interaction between the vorticity and the zonal gradient of cloud heating. The results demonstrate that the vertical component of the CVV is a cloud-linked parameter and can be used to study tropical convection.

  8. 2D vs. 3D mammography observer study

    NASA Astrophysics Data System (ADS)

    Fernandez, James Reza F.; Hovanessian-Larsen, Linda; Liu, Brent

    2011-03-01

    Breast cancer is the most common type of non-skin cancer in women. 2D mammography is a screening tool to aid in the early detection of breast cancer, but has diagnostic limitations of overlapping tissues, especially in dense breasts. 3D mammography has the potential to improve detection outcomes by increasing specificity, and a new 3D screening tool with a 3D display for mammography aims to improve performance and efficiency as compared to 2D mammography. An observer study using a mammography phantom was performed to compare traditional 2D mammography with this ne 3D mammography technique. In comparing 3D and 2D mammography there was no difference in calcification detection, and mass detection was better in 2D as compared to 3D. There was a significant decrease in reading time for masses, calcifications, and normals in 3D compared to 2D, however, as well as more favorable confidence levels in reading normal cases. Given the limitations of the mammography phantom used, however, a clearer picture in comparing 3D and 2D mammography may be better acquired with the incorporation of human studies in the future.

  9. Investigating digit ratio (2D:4D) in a highly male-dominated occupation: the case of firefighters.

    PubMed

    Voracek, Martin; Pum, Ulrike; Dressler, Stefan G

    2010-04-01

    Second-to-fourth digit ratio (2D:4D), a widely studied putative marker for masculinization through prenatal androgen exposure, is lower (more masculinized) in athletes than in general population controls, and athletes with lower 2D:4D have higher sporting success. Occupations differ markedly in perceived masculinity and actual maleness (sex ratios), but these givens have not yet been picked up and utilized in 2D:4D research. Accordingly, this study extended existing accounts on 2D:4D in athletes to a novel approach: 2D:4D and possible relationships to a variety of candidate variables (demographic, fertility-related, psychological, and other) were investigated in firefighters, a highly male-dominated occupation. Contrary to expectation, 2D:4D in firefighters (N = 134) was not lower than in local male population controls. Lower 2D:4D corresponded to lower service ranks. Replicating previous findings either unequivocally or partly, lower 2D:4D was associated with larger family size, later sibling position, left-handedness, and higher scores in the disinhibition component of sensation seeking. Not replicating prior evidence, 2D:4D was unrelated to body-mass index, offspring sex ratio, and sporting performance level. Novel findings included low 2D:4D in those with low relationship satisfaction and in cigarette smokers, especially among heavy smokers. Absolute finger length, a positive correlate of pubertal-adolescent androgen levels, was also considered. This marker showed negative associations with relationship consensus and satisfaction and positive ones with perceived quality of relationship alternatives and the experience seeking component of sensation seeking. The merits of this additional marker, relative to 2D:4D, for supplementing studies of possible sex-hormonal effects on personality and directions for future inquiry along these lines are discussed.

  10. Arabidopsis metacaspase 2d is a positive mediator of cell death induced during biotic and abiotic stresses.

    PubMed

    Watanabe, Naohide; Lam, Eric

    2011-06-01

    Cysteine proteases such as caspases play important roles in programmed cell death (PCD) of metazoans. Plant metacaspases (MCPs), a family of cysteine proteases structurally related to caspases, have been hypothesized to be ancestors of metazoan caspases, despite their different substrate specificity. Arabidopsis thaliana contains six type II MCP genes (AtMCP2a-f). Whether and how these individual members are involved in controlling PCD in plants remains largely unknown. Here we investigated the function and regulation of AtMCP2d, the predominant and constitutively expressed member of type II MCPs, in stress-inducible PCD. Two AtMCP2d mutants (mcp2d-1 and mcp2d-3) exhibited reduced sensitivity to PCD-inducing mycotoxin fumonisin B1 as well as oxidative stress inducers, whereas AtMCP2d over-expressors were more sensitive to these agents, and exhibited accelerated cell-death progression. We found that AtMCP2d exclusively localizes to the cytosol, and its accumulation and self-processing patterns were age-dependent in leaves. Importantly, active proteolytic processing of AtMCP2d proteins dependent on its catalytic activity was observed in mature leaves during mycotoxin-induced cell death. We also found that mcp2d-1 leaves exhibited reduced cell death in response to Pseudomonas syringae carrying avirulent gene avrRpt2, and that self-processing of AtMCP2d was also detected in wild-type leaves in response to this pathogen. Furthermore, increases in processed AtMCP2d proteins were found to correlate with conditional cell-death induction in two lesion-mimic mutants (cpr22 and ssi4) that exhibit spontaneous cell-death phenotypes. Taken together, our data strongly suggest that AtMCP2d plays a positive regulatory role in biotic and abiotic stress-induced PCD.

  11. Thermodynamic properties of the 2D frustrated Heisenberg model for the entire J1 -J2 circle

    NASA Astrophysics Data System (ADS)

    Mikheyenkov, A. V.; Shvartsberg, A. V.; Valiulin, V. E.; Barabanov, A. F.

    2016-12-01

    Using the spherically symmetric self-consistent Green's function method, we consider thermodynamic properties of the S = 1 / 2J1 -J2 Heisenberg model on the 2D square lattice. We calculate the temperature dependence of the spin-spin correlation functions cr = < S0z Srz >, the gaps in the spin excitation spectrum, the energy E and the heat capacity CV for the whole J1-J2-circle, i.e. for arbitrary φ, J1 = cos (φ), J2 = sin (φ). Due to low dimension there is no long-range order at T ≠ 0, but the short-range holds the memory of the parent zero-temperature ordered phase (antiferromagnetic, stripe or ferromagnetic). E(φ) and CV(φ) demonstrate extrema "above" the long-range ordered phases and in the regions of rapid short-range rearranging. Tracts of cr(φ) lines have several nodes leading to nonmonotonic cr(T) dependence. For any fixed φ the heat capacity CV(T) always has maximum, tending to zero at T → 0, in the narrow vicinity of φ = 155 ° it exhibits an additional frustration-induced low-temperature maximum. We have also found the nonmonotonic behaviour of the spin gaps at φ = 270 ° ± 0 and exponentially small antiferromagnetic gap up to (T ≲ 0.5) for φ ≳ 270 °.

  12. Joint 2D and 3D phase processing for quantitative susceptibility mapping: application to 2D echo-planar imaging.

    PubMed

    Wei, Hongjiang; Zhang, Yuyao; Gibbs, Eric; Chen, Nan-Kuei; Wang, Nian; Liu, Chunlei

    2017-04-01

    Quantitative susceptibility mapping (QSM) measures tissue magnetic susceptibility and typically relies on time-consuming three-dimensional (3D) gradient-echo (GRE) MRI. Recent studies have shown that two-dimensional (2D) multi-slice gradient-echo echo-planar imaging (GRE-EPI), which is commonly used in functional MRI (fMRI) and other dynamic imaging techniques, can also be used to produce data suitable for QSM with much shorter scan times. However, the production of high-quality QSM maps is difficult because data obtained by 2D multi-slice scans often have phase inconsistencies across adjacent slices and strong susceptibility field gradients near air-tissue interfaces. To address these challenges in 2D EPI-based QSM studies, we present a new data processing procedure that integrates 2D and 3D phase processing. First, 2D Laplacian-based phase unwrapping and 2D background phase removal are performed to reduce phase inconsistencies between slices and remove in-plane harmonic components of the background phase. This is followed by 3D background phase removal for the through-plane harmonic components. The proposed phase processing was evaluated with 2D EPI data obtained from healthy volunteers, and compared against conventional 3D phase processing using the same 2D EPI datasets. Our QSM results were also compared with QSM values from time-consuming 3D GRE data, which were taken as ground truth. The experimental results show that this new 2D EPI-based QSM technique can produce quantitative susceptibility measures that are comparable with those of 3D GRE-based QSM across different brain regions (e.g. subcortical iron-rich gray matter, cortical gray and white matter). This new 2D EPI QSM reconstruction method is implemented within STI Suite, which is a comprehensive shareware for susceptibility imaging and quantification. Copyright © 2016 John Wiley & Sons, Ltd.

  13. NKG2D receptor and its ligands in host defense

    PubMed Central

    Lanier, Lewis L.

    2015-01-01

    NKG2D is an activating receptor expressed on the surface of natural killer (NK) cells, CD8+ T cells, and subsets of CD4+ T cells, iNKT cells, and γδ T cells. In humans NKG2D transmits signals by its association with the DAP10 adapter subunit and in mice alternatively spliced isoforms transmit signals either using DAP10 or DAP12 adapter subunits. Although NKG2D is encoded by a highly conserved gene (KLRK1) with limited polymorphism, the receptor recognizes an extensive repertoire of ligands, encoded by at least 8 genes in humans (MICA, MICB, RAET1E, RAET1G, RAET1H, RAET1I, RAET1L, and RAET1N), some with extensive allelic polymorphism. Expression of the NKG2D ligands is tightly regulated at the level of transcription, translation, and post-translation. In general healthy adult tissues do not express NKG2D glycoproteins on the cell surface, but these ligands can be induced by hyper-proliferation and transformation, as well as when cells are infected by pathogens. Thus, the NKG2D pathway serves a mechanism for the immune system to detect and eliminate cells that have undergone “stress”. Viruses and tumor cells have devised numerous strategies to evade detection by the NKG2D surveillance system and diversification of the NKG2D ligand genes likely has been driven by selective pressures imposed by pathogens. NKG2D provides an attractive target for therapeutics in the treatment of infectious diseases, cancer, and autoimmune diseases. PMID:26041808

  14. NKG2D Receptor and Its Ligands in Host Defense.

    PubMed

    Lanier, Lewis L

    2015-06-01

    NKG2D is an activating receptor expressed on the surface of natural killer (NK) cells, CD8(+) T cells, and subsets of CD4(+) T cells, invariant NKT cells (iNKT), and γδ T cells. In humans, NKG2D transmits signals by its association with the DAP10 adapter subunit, and in mice alternatively spliced isoforms transmit signals either using DAP10 or DAP12 adapter subunits. Although NKG2D is encoded by a highly conserved gene (KLRK1) with limited polymorphism, the receptor recognizes an extensive repertoire of ligands, encoded by at least eight genes in humans (MICA, MICB, RAET1E, RAET1G, RAET1H, RAET1I, RAET1L, and RAET1N), some with extensive allelic polymorphism. Expression of the NKG2D ligands is tightly regulated at the level of transcription, translation, and posttranslation. In general, healthy adult tissues do not express NKG2D glycoproteins on the cell surface, but these ligands can be induced by hyperproliferation and transformation, as well as when cells are infected by pathogens. Thus, the NKG2D pathway serves as a mechanism for the immune system to detect and eliminate cells that have undergone "stress." Viruses and tumor cells have devised numerous strategies to evade detection by the NKG2D surveillance system, and diversification of the NKG2D ligand genes likely has been driven by selective pressures imposed by pathogens. NKG2D provides an attractive target for therapeutics in the treatment of infectious diseases, cancer, and autoimmune diseases.

  15. 2-D Versus 3-D Magnetotelluric Data Interpretation

    NASA Astrophysics Data System (ADS)

    Ledo, Juanjo

    2005-09-01

    In recent years, the number of publications dealing with the mathematical and physical 3-D aspects of the magnetotelluric method has increased drastically. However, field experiments on a grid are often impractical and surveys are frequently restricted to single or widely separated profiles. So, in many cases we find ourselves with the following question: is the applicability of the 2-D hypothesis valid to extract geoelectric and geological information from real 3-D environments? The aim of this paper is to explore a few instructive but general situations to understand the basics of a 2-D interpretation of 3-D magnetotelluric data and to determine which data subset (TE-mode or TM-mode) is best for obtaining the electrical conductivity distribution of the subsurface using 2-D techniques. A review of the mathematical and physical fundamentals of the electromagnetic fields generated by a simple 3-D structure allows us to prioritise the choice of modes in a 2-D interpretation of responses influenced by 3-D structures. This analysis is corroborated by numerical results from synthetic models and by real data acquired by other authors. One important result of this analysis is that the mode most unaffected by 3-D effects depends on the position of the 3-D structure with respect to the regional 2-D strike direction. When the 3-D body is normal to the regional strike, the TE-mode is affected mainly by galvanic effects, while the TM-mode is affected by galvanic and inductive effects. In this case, a 2-D interpretation of the TM-mode is prone to error. When the 3-D body is parallel to the regional 2-D strike the TE-mode is affected by galvanic and inductive effects and the TM-mode is affected mainly by galvanic effects, making it more suitable for 2-D interpretation. In general, a wise 2-D interpretation of 3-D magnetotelluric data can be a guide to a reasonable geological interpretation.

  16. Investigation on the spectral properties of 2D asynchronous fluorescence spectra generated by using variable excitation wavelengths as a perturbation

    NASA Astrophysics Data System (ADS)

    Wang, Jingdan; He, Anqi; Guo, Ran; Wei, Yongju; Feng, Juan; Xu, Yizhuang; Noda, Isao; Wu, Jinguang

    2016-11-01

    Properties of 2D asynchronous spectra generated from a series of fluorescence emission spectra are investigated. Variable excitation wavelengths are utilized as an external perturbation. Based on the results of mathematical analysis and computer simulation, we find that no cross peak will be produced on the 2D asynchronous spectrum if the fluorescent solute under investigation occurs in a single micro-environment. The observation of cross peaks implies that the fluorescent molecule may occur in different micro-environments in a solution. Based on these results, we use 2D asynchronous spectra to investigate the emission spectra of anthracene dissolved in cyclohexane. When the concentration of anthracene is low, no cross peak is produced in the resultant 2D asynchronous spectrum, confirming that anthracene is dissolved as single molecule in the solution. As the concentration elevated, cross peaks appear in the corresponding 2D asynchronous spectra. A plausible explanation of this phenomenon is that anthracene may undergo aggregation via π-π interaction or π-C-H interaction.

  17. Recent advances in 2D materials for photocatalysis.

    PubMed

    Luo, Bin; Liu, Gang; Wang, Lianzhou

    2016-04-07

    Two-dimensional (2D) materials have attracted increasing attention for photocatalytic applications because of their unique thickness dependent physical and chemical properties. This review gives a brief overview of the recent developments concerning the chemical synthesis and structural design of 2D materials at the nanoscale and their applications in photocatalytic areas. In particular, recent progress on the emerging strategies for tailoring 2D material-based photocatalysts to improve their photo-activity including elemental doping, heterostructure design and functional architecture assembly is discussed.

  18. Comparison of 2D and 3D gamma analyses

    SciTech Connect

    Pulliam, Kiley B.; Huang, Jessie Y.; Howell, Rebecca M.; Followill, David; Kry, Stephen F.; Bosca, Ryan; O’Daniel, Jennifer

    2014-02-15

    Purpose: As clinics begin to use 3D metrics for intensity-modulated radiation therapy (IMRT) quality assurance, it must be noted that these metrics will often produce results different from those produced by their 2D counterparts. 3D and 2D gamma analyses would be expected to produce different values, in part because of the different search space available. In the present investigation, the authors compared the results of 2D and 3D gamma analysis (where both datasets were generated in the same manner) for clinical treatment plans. Methods: Fifty IMRT plans were selected from the authors’ clinical database, and recalculated using Monte Carlo. Treatment planning system-calculated (“evaluated dose distributions”) and Monte Carlo-recalculated (“reference dose distributions”) dose distributions were compared using 2D and 3D gamma analysis. This analysis was performed using a variety of dose-difference (5%, 3%, 2%, and 1%) and distance-to-agreement (5, 3, 2, and 1 mm) acceptance criteria, low-dose thresholds (5%, 10%, and 15% of the prescription dose), and data grid sizes (1.0, 1.5, and 3.0 mm). Each comparison was evaluated to determine the average 2D and 3D gamma, lower 95th percentile gamma value, and percentage of pixels passing gamma. Results: The average gamma, lower 95th percentile gamma value, and percentage of passing pixels for each acceptance criterion demonstrated better agreement for 3D than for 2D analysis for every plan comparison. The average difference in the percentage of passing pixels between the 2D and 3D analyses with no low-dose threshold ranged from 0.9% to 2.1%. Similarly, using a low-dose threshold resulted in a difference between the mean 2D and 3D results, ranging from 0.8% to 1.5%. The authors observed no appreciable differences in gamma with changes in the data density (constant difference: 0.8% for 2D vs 3D). Conclusions: The authors found that 3D gamma analysis resulted in up to 2.9% more pixels passing than 2D analysis. It must

  19. Theoretical investigation on a general class of 2D quasicrystals with the rectangular projection method

    NASA Astrophysics Data System (ADS)

    Yue, Yang-Yang; Lu, Rong-er; Yang, Bo; Huang, Huang; Hong, Xu-Hao; Zhang, Chao; Qin, Yi-Qiang; Zhu, Yong-Yuan

    2016-10-01

    We take a theoretical investigation on the reciprocal property of a class of 2D nonlinear photonic quasicrystal proposed by Lifshitz et al. in PRL 95, 133901 (2005). Using the rectangular projection method, the analytical expression for the Fourier spectrum of the quasicrystal structure is obtained explicitly. It is interesting to find that the result has a similar form to the corresponding expression of the well-known 1D Fibonacci lattice. In addition, we predict a further extension of the result to higher dimensions. This work is of practical importance for the photonic device design in nonlinear optical conversion progresses.

  20. Chiral scale and conformal invariance in 2D quantum field theory.

    PubMed

    Hofman, Diego M; Strominger, Andrew

    2011-10-14

    It is well known that a local, unitary Poincaré-invariant 2D quantum field theory with a global scaling symmetry and a discrete non-negative spectrum of scaling dimensions necessarily has both a left and a right local conformal symmetry. In this Letter, we consider a chiral situation beginning with only a left global scaling symmetry and do not assume Lorentz invariance. We find that a left conformal symmetry is still implied, while right translations are enhanced either to a right conformal symmetry or a left U(1) Kac-Moody symmetry.

  1. Optical design of wavelength selective CPVT system with 3D/2D hybrid concentration

    NASA Astrophysics Data System (ADS)

    Ahmad, N.; Ijiro, T.; Yamada, N.; Kawaguchi, T.; Maemura, T.; Ohashi, H.

    2012-10-01

    Optical design of a concentrating photovoltaic/thermal (CPVT) system is carried out. Using wavelength-selective optics, the system demonstrates 3-D concentration onto a solar cell and 2-D concentration onto a thermal receiver. Characteristics of the two types of concentrator systems are examined with ray-tracing analysis. The first system is a glazed mirror-based concentrator system mounted on a 2-axis pedestal tracker. The size of the secondary optical element is minimized to decrease the cost of the system, and it has a wavelength-selective function for performing 3-D concentration onto a solar cell and 2-D concentration onto a thermal receiver. The second system is a non-glazed beamdown concentrator system containing parabolic mirrors in the lower part. The beam-down selective mirror performs 3-D concentration onto a solar cell placed above the beam-down selective mirror, and 2-D concentration down to a thermal receiver placed at the bottom level. The system is mounted on a two-axis carousel tracker. A parametric study is performed for those systems with different geometrical 2-D/3-D concentration ratios. Wavelength-selective optics such as hot/cold mirrors and spectrum-splitting technologies are taken into account in the analysis. Results show reduced heat load on the solar cell and increased total system efficiency compared to a non-selective CPV system. Requirements for the wavelength-selective properties are elucidated. It is also shown that the hybrid concept with 2-D concentration onto a thermal receiver and 3-D concentration onto a solar cell has an advantageous geometry because of the high total system efficiency and compatibility with the piping arrangement of the thermal receiver.

  2. Human papillomavirus genotype spectrum in Czech women: correlation of HPV DNA presence with antibodies against HPV-16, 18, and 33 virus-like particles.

    PubMed

    Tachezy, R; Hamsíková, E; Hájek, T; Mikysková, I; Smahel, M; Van Ranst, M; Kanka, J; Havránková, A; Rob, L; Guttner, V; Slavík, V; Anton, M; Kratochvíl, B; Kotrsová, L; Vonka, V

    1999-08-01

    Because the biological spectrum of human papillomavirus (HPV) genotypes present in cervical cancer lesions varies according to the geographical region studied, and because little genotype information is available for Central and Eastern European countries, we studied the endemic HPV-genotype spectrum in cervical samples collected from women visiting gynaecological departments of selected hospitals in the Czech Republic. In a series of 389 samples, 171 (44.0%) were positive for HPV DNA using a consensus-primer polymerase chain reaction (PCR). Genotyping of the HPV PCR products was done using dot-blot hybridisation with type-specific oligonucleotide probes and thermocycle DNA sequencing. Twenty-two different HPV types were detected, HPV-16 being the most prevalent type irrespective of severity of the lesions (55.0%). Multiple HPV types were found in 16.4% of our HPV-DNA-positive samples. The prevalence of HPV infection was 23.0% in women with normal findings and 59.4% in patients with cervical neoplasia, and increased significantly with the severity of the disease: 52.9% in low-grade lesions, 58.0% in high-grade lesions, and 73.5% in cervical carcinomas (P for trend < .00001). In the sera of 191 subjects, 89 with normal findings and 102 with different forms of cervical neoplasia, the prevalence of HPV-specific IgG antibodies was tested by an enzyme-linked immunosorbent assay (ELISA) using virus-like particles (VLPs) of HPV-16, -18, and -33. Antibodies were significantly more prevalent in HPV-DNA-positive than in HPV-DNA-negative women and there was no association with age. In agreement with the results of HPV genotyping, antibodies reactive with HPV-16 VLPs were the most frequent and, moreover, their prevalence increased with the cervical lesion severity. About half of the subjects with smears in which either HPV-16 or HPV-33 DNA had been detected possessed antibodies reactive with homotypic VLPs. With HPV-18-DNA-positive subjects, however, fewer than 25% displayed

  3. 2D and 3D anatomical analyses of hand dimensions for custom-made gloves.

    PubMed

    Yu, A; Yick, K L; Ng, S P; Yip, J

    2013-05-01

    Measuring hand anthropometric data for the development of good-fitting gloves is crucial. In pursuing higher accuracy in hand anthropometric measurements, scanning of hand surfaces with the aids of image analysis system to acquire measurements is an alternative to the manual methods. This study proposes a new hand measuring approach by using 2D and 3D scanning which are evaluated through comparisons of manual measurements. Thirty-three dimensions are measured by using (1) tape and calliper measurement; (2) 2D image analysis; (3) 3D image analysis based on ten captures; and (4) 3D image analysis based on three captures, respectively. Repeated-measures ANOVA, correlation analysis and RMSE are used to examine the results. The hand dimensions obtained from the four methods are highly linearly correlated. Hand data taken from 3D image analysis has no significant difference compared with manual measurements on hand and wrist circumferences, length and breadth dimension, regardless of the number of captures.

  4. Double resonance rotational spectroscopy of CH2D+

    NASA Astrophysics Data System (ADS)

    Töpfer, Matthias; Jusko, Pavol; Schlemmer, Stephan; Asvany, Oskar

    2016-09-01

    Context. Deuterated forms of CH are thought to be responsible for deuterium enrichment in lukewarm astronomical environments. There is no unambiguous detection of CH2D+ in space to date. Aims: Four submillimetre rotational lines of CH2D+ are documented in the literature. Our aim is to present a complete dataset of highly resolved rotational lines, including millimetre (mm) lines needed for a potential detection. Methods: We used a low-temperature ion trap and applied a novel IR-mm-wave double resonance method to measure the rotational lines of CH2D+. Results: We measured 21 low-lying (J ≤ 4) rotational transitions of CH2D+ between 23 GHz and 1.1 THz with accuracies close to 2 ppb.

  5. Recovering 3D particle size distributions from 2D sections

    NASA Astrophysics Data System (ADS)

    Cuzzi, Jeffrey N.; Olson, Daniel M.

    2017-03-01

    We discuss different ways to convert observed, apparent particle size distributions from 2D sections (thin sections, SEM maps on planar surfaces, etc.) into true 3D particle size distributions. We give a simple, flexible, and practical method to do this; show which of these techniques gives the most faithful conversions; and provide (online) short computer codes to calculate both 2D-3D recoveries and simulations of 2D observations by random sectioning. The most important systematic bias of 2D sectioning, from the standpoint of most chondrite studies, is an overestimate of the abundance of the larger particles. We show that fairly good recoveries can be achieved from observed size distributions containing 100-300 individual measurements of apparent particle diameter.

  6. Phonon thermal conduction in novel 2D materials

    NASA Astrophysics Data System (ADS)

    Xu, Xiangfan; Chen, Jie; Li, Baowen

    2016-12-01

    Recently, there has been increasing interest in phonon thermal transport in low-dimensional materials, due to the crucial importance of dissipating and managing heat in micro- and nano-electronic devices. Significant progress has been achieved for one-dimensional (1D) systems, both theoretically and experimentally. However, the study of heat conduction in two-dimensional (2D) systems is still in its infancy due to the limited availability of 2D materials and the technical challenges of fabricating suspended samples that are suitable for thermal measurements. In this review, we outline different experimental techniques and theoretical approaches for phonon thermal transport in 2D materials, discuss the problems and challenges of phonon thermal transport measurements and provide a comparison between existing experimental data. Special attention will be given to the effects of size, dimensionality, anisotropy and mode contributions in novel 2D systems, including graphene, boron nitride, MoS2, black phosphorous and silicene.

  7. Recent developments in 2D layered inorganic nanomaterials for sensing

    NASA Astrophysics Data System (ADS)

    Kannan, Padmanathan Karthick; Late, Dattatray J.; Morgan, Hywel; Rout, Chandra Sekhar

    2015-08-01

    Two dimensional layered inorganic nanomaterials (2D-LINs) have recently attracted huge interest because of their unique thickness dependent physical and chemical properties and potential technological applications. The properties of these layered materials can be tuned via both physical and chemical processes. Some 2D layered inorganic nanomaterials like MoS2, WS2 and SnS2 have been recently developed and employed in various applications, including new sensors because of their layer-dependent electrical properties. This article presents a comprehensive overview of recent developments in the application of 2D layered inorganic nanomaterials as sensors. Some of the salient features of 2D materials for different sensing applications are discussed, including gas sensing, electrochemical sensing, SERS and biosensing, SERS sensing and photodetection. The working principles of the sensors are also discussed together with examples.

  8. Phonon thermal conduction in novel 2D materials.

    PubMed

    Xu, Xiangfan; Chen, Jie; Li, Baowen

    2016-12-07

    Recently, there has been increasing interest in phonon thermal transport in low-dimensional materials, due to the crucial importance of dissipating and managing heat in micro- and nano-electronic devices. Significant progress has been achieved for one-dimensional (1D) systems, both theoretically and experimentally. However, the study of heat conduction in two-dimensional (2D) systems is still in its infancy due to the limited availability of 2D materials and the technical challenges of fabricating suspended samples that are suitable for thermal measurements. In this review, we outline different experimental techniques and theoretical approaches for phonon thermal transport in 2D materials, discuss the problems and challenges of phonon thermal transport measurements and provide a comparison between existing experimental data. Special attention will be given to the effects of size, dimensionality, anisotropy and mode contributions in novel 2D systems, including graphene, boron nitride, MoS2, black phosphorous and silicene.

  9. Exact Solution of Ising Model in 2d Shortcut Network

    NASA Astrophysics Data System (ADS)

    Shanker, O.

    We give the exact solution to the Ising model in the shortcut network in the 2D limit. The solution is found by mapping the model to the square lattice model with Brascamp and Kunz boundary conditions.

  10. Technical Review of the UNET2D Hydraulic Model

    SciTech Connect

    Perkins, William A.; Richmond, Marshall C.

    2009-05-18

    The Kansas City District of the US Army Corps of Engineers is engaged in a broad range of river management projects that require knowledge of spatially-varied hydraulic conditions such as velocities and water surface elevations. This information is needed to design new structures, improve existing operations, and assess aquatic habitat. Two-dimensional (2D) depth-averaged numerical hydraulic models are a common tool that can be used to provide velocity and depth information. Kansas City District is currently using a specific 2D model, UNET2D, that has been developed to meet the needs of their river engineering applications. This report documents a tech- nical review of UNET2D.

  11. Reconstruction-based 3D/2D image registration.

    PubMed

    Tomazevic, Dejan; Likar, Bostjan; Pernus, Franjo

    2005-01-01

    In this paper we present a novel 3D/2D registration method, where first, a 3D image is reconstructed from a few 2D X-ray images and next, the preoperative 3D image is brought into the best possible spatial correspondence with the reconstructed image by optimizing a similarity measure. Because the quality of the reconstructed image is generally low, we introduce a novel asymmetric mutual information similarity measure, which is able to cope with low image quality as well as with different imaging modalities. The novel 3D/2D registration method has been evaluated using standardized evaluation methodology and publicly available 3D CT, 3DRX, and MR and 2D X-ray images of two spine phantoms, for which gold standard registrations were known. In terms of robustness, reliability and capture range the proposed method outperformed the gradient-based method and the method based on digitally reconstructed radiographs (DRRs).

  12. Alloyed 2D Metal-Semiconductor Atomic Layer Junctions.

    PubMed

    Kim, Ah Ra; Kim, Yonghun; Nam, Jaewook; Chung, Hee-Suk; Kim, Dong Jae; Kwon, Jung-Dae; Park, Sang Won; Park, Jucheol; Choi, Sun Young; Lee, Byoung Hun; Park, Ji Hyeon; Lee, Kyu Hwan; Kim, Dong-Ho; Choi, Sung Mook; Ajayan, Pulickel M; Hahm, Myung Gwan; Cho, Byungjin

    2016-03-09

    Heterostructures of compositionally and electronically variant two-dimensional (2D) atomic layers are viable building blocks for ultrathin optoelectronic devices. We show that the composition of interfacial transition region between semiconducting WSe2 atomic layer channels and metallic NbSe2 contact layers can be engineered through interfacial doping with Nb atoms. WxNb1-xSe2 interfacial regions considerably lower the potential barrier height of the junction, significantly improving the performance of the corresponding WSe2-based field-effect transistor devices. The creation of such alloyed 2D junctions between dissimilar atomic layer domains could be the most important factor in controlling the electronic properties of 2D junctions and the design and fabrication of 2D atomic layer devices.

  13. Studying Zeolite Catalysts with a 2D Model System

    SciTech Connect

    Boscoboinik, Anibal

    2016-12-07

    Anibal Boscoboinik, a materials scientist at Brookhaven’s Center for Functional Nanomaterials, discusses the surface-science tools and 2D model system he uses to study catalysis in nanoporous zeolites, which catalyze reactions in many industrial processes.

  14. ORION96. 2-d Finite Element Code Postprocessor

    SciTech Connect

    Sanford, L.A.; Hallquist, J.O.

    1992-02-02

    ORION is an interactive program that serves as a postprocessor for the analysis programs NIKE2D, DYNA2D, TOPAZ2D, and CHEMICAL TOPAZ2D. ORION reads binary plot files generated by the two-dimensional finite element codes currently used by the Methods Development Group at LLNL. Contour and color fringe plots of a large number of quantities may be displayed on meshes consisting of triangular and quadrilateral elements. ORION can compute strain measures, interface pressures along slide lines, reaction forces along constrained boundaries, and momentum. ORION has been applied to study the response of two-dimensional solids and structures undergoing finite deformations under a wide variety of large deformation transient dynamic and static problems and heat transfer analyses.

  15. Emerging and potential opportunities for 2D flexible nanoelectronics

    NASA Astrophysics Data System (ADS)

    Zhu, Weinan; Park, Saungeun; Akinwande, Deji

    2016-05-01

    The last 10 years have seen the emergence of two-dimensional (2D) nanomaterials such as graphene, transition metal dichalcogenides (TMDs), and black phosphorus (BP) among the growing portfolio of layered van der Waals thin films. Graphene, the prototypical 2D material has advanced rapidly in device, circuit and system studies that has resulted in commercial large-area applications. In this work, we provide a perspective of the emerging and potential translational applications of 2D materials including semiconductors, semimetals, and insulators that comprise the basic material set for diverse nanosystems. Applications include RF transceivers, smart systems, the so-called internet of things, and neurotechnology. We will review the DC and RF electronic performance of graphene and BP thin film transistors. 2D materials at sub-um channel length have so far enabled cut-off frequencies from baseband to 100GHz suitable for low-power RF and sub-THz concepts.

  16. Anisotropic 2D Materials for Tunable Hyperbolic Plasmonics.

    PubMed

    Nemilentsau, Andrei; Low, Tony; Hanson, George

    2016-02-12

    Motivated by the recent emergence of a new class of anisotropic 2D materials, we examine their electromagnetic modes and demonstrate that a broad class of the materials can host highly directional hyperbolic plasmons. Their propagation direction can be manipulated on the spot by gate doping, enabling hyperbolic beam reflection, refraction, and bending. The realization of these natural 2D hyperbolic media opens up a new avenue in dynamic control of hyperbolic plasmons not possible in the 3D version.

  17. RNA folding pathways and kinetics using 2D energy landscapes.

    PubMed

    Senter, Evan; Dotu, Ivan; Clote, Peter

    2015-01-01

    RNA folding pathways play an important role in various biological processes, such as (i) the hok/sok (host-killing/suppression of killing) system in E. coli to check for sufficient plasmid copy number, (ii) the conformational switch in spliced leader (SL) RNA from Leptomonas collosoma, which controls trans splicing of a portion of the '5 exon, and (iii) riboswitches--portions of the 5' untranslated region of messenger RNA that regulate genes by allostery. Since RNA folding pathways are determined by the energy landscape, we describe a novel algorithm, FFTbor2D, which computes the 2D projection of the energy landscape for a given RNA sequence. Given two metastable secondary structures A, B for a given RNA sequence, FFTbor2D computes the Boltzmann probability p(x, y) = Z(x,y)/Z that a secondary structure has base pair distance x from A and distance y from B. Using polynomial interpolationwith the fast Fourier transform,we compute p(x, y) in O(n(5)) time and O(n(2)) space, which is an improvement over an earlier method, which runs in O(n(7)) time and O(n(4)) space. FFTbor2D has potential applications in synthetic biology, where one might wish to design bistable switches having target metastable structures A, B with favorable pathway kinetics. By inverting the transition probability matrix determined from FFTbor2D output, we show that L. collosoma spliced leader RNA has larger mean first passage time from A to B on the 2D energy landscape, than 97.145% of 20,000 sequences, each having metastable structures A, B. Source code and binaries are freely available for download at http://bioinformatics.bc.edu/clotelab/FFTbor2D. The program FFTbor2D is implemented in C++, with optional OpenMP parallelization primitives.

  18. Supported and Free-Standing 2D Semimetals

    DTIC Science & Technology

    2015-01-15

    of this effort on focusing on rare- earth arsenides (RE-A), although not a van der Waals 2D solid, nonetheless, exhibits substantial 2D quantum size...this effort on focusing on rare- earth arsenides (RE- A), although not a van der Waals 20 solid, nonetheless, exhibits substantial 20 quantum size...Brongersma and S.R. Bank, "Rare- earth monopnictide alloys for tunable, epitaxial metals" in preparation. iii. S. Rahimi, E. M. Krivoy, J. Lee, M. E

  19. Application of 2-D graphical representation of DNA sequence

    NASA Astrophysics Data System (ADS)

    Liao, Bo; Tan, Mingshu; Ding, Kequan

    2005-10-01

    Recently, we proposed a 2-D graphical representation of DNA sequence [Bo Liao, A 2-D graphical representation of DNA sequence, Chem. Phys. Lett. 401 (2005) 196-199]. Based on this representation, we consider properties of mutations and compute the similarities among 11 mitochondrial sequences belonging to different species. The elements of the similarity matrix are used to construct phylogenic tree. Unlike most existing phylogeny construction methods, the proposed method does not require multiple alignment.

  20. phase_space_cosmo_fisher: Fisher matrix 2D contours

    NASA Astrophysics Data System (ADS)

    Stark, Alejo

    2016-11-01

    phase_space_cosmo_fisher produces Fisher matrix 2D contours from which the constraints on cosmological parameters can be derived. Given a specified redshift array and cosmological case, 2D marginalized contours of cosmological parameters are generated; the code can also plot the derivatives used in the Fisher matrix. In addition, this package can generate 3D plots of qH^2 and other cosmological quantities as a function of redshift and cosmology.

  1. A simultaneous 2D/3D autostereo workstation

    NASA Astrophysics Data System (ADS)

    Chau, Dennis; McGinnis, Bradley; Talandis, Jonas; Leigh, Jason; Peterka, Tom; Knoll, Aaron; Sumer, Aslihan; Papka, Michael; Jellinek, Julius

    2012-03-01

    We present a novel immersive workstation environment that scientists can use for 3D data exploration and as their everyday 2D computer monitor. Our implementation is based on an autostereoscopic dynamic parallax barrier 2D/3D display, interactive input devices, and a software infrastructure that allows client/server software modules to couple the workstation to scientists' visualization applications. This paper describes the hardware construction and calibration, software components, and a demonstration of our system in nanoscale materials science exploration.

  2. Phylogenetic tree construction based on 2D graphical representation

    NASA Astrophysics Data System (ADS)

    Liao, Bo; Shan, Xinzhou; Zhu, Wen; Li, Renfa

    2006-04-01

    A new approach based on the two-dimensional (2D) graphical representation of the whole genome sequence [Bo Liao, Chem. Phys. Lett., 401(2005) 196.] is proposed to analyze the phylogenetic relationships of genomes. The evolutionary distances are obtained through measuring the differences among the 2D curves. The fuzzy theory is used to construct phylogenetic tree. The phylogenetic relationships of H5N1 avian influenza virus illustrate the utility of our approach.

  3. Isolation and 2D NMR Studies of Alkaloids from Comptonella sessilifoliola1.

    PubMed

    Pusset, J; Lopez, J L; Pais, M; Neirabeyeh, M A; Veillon, J M

    1991-04-01

    Six known furanoquinoline alkaloids have been isolated from the wood and trunk bark of COMPTONELLA SESSILIFOLIOLA (Guillaumin) Hartley (Rutaceae). 2D NMR experiments gave the assignment of all the signals for both (1)H- and (13)C-NMR spectra. Pteleine and kokusaginine were used as models. The two-dimensional carbon-proton correlation experiments, performed for the first time on furanoquinoline alkaloids, led us to correct (13)C-NMR assignments previously described in the literature.

  4. Regulation of NKG2D ligand gene expression.

    PubMed

    Eagle, Robert A; Traherne, James A; Ashiru, Omodele; Wills, Mark R; Trowsdale, John

    2006-03-01

    The activating immunoreceptor NKG2D has seven known host ligands encoded by the MHC class I chain-related MIC and ULBP/RAET genes. Why there is such diversity of NKG2D ligands is not known but one hypothesis is that they are differentially expressed in different tissues in response to different stresses. To explore this, we compared expression patterns and promoters of NKG2D ligand genes. ULBP/RAET genes were transcribed independent of each other in a panel of cell lines. ULBP/RAET gene expression was upregulated on infection with human cytomegalovirus; however, a clinical strain, Toledo, induced expression more slowly than did a laboratory strain, AD169. ULBP4/RAET1E was not induced by infection with either strain. To investigate the mechanisms behind the similarities and differences in NKG2D ligand gene expression a comparative sequence analysis of NKG2D ligand gene putative promoter regions was conducted. Sequence alignments demonstrated that there was significant sequence diversity; however, one region of high similarity between most of the genes is evident. This region contains a number of potential transcription factor binding sites, including those involved in shock responses and sites for retinoic acid-induced factors. Promoters of some NKG2D ligand genes are polymorphic and several sequence alterations in these alleles abolished putative transcription factor binding.

  5. CYP2D6 variability in populations from Venezuela.

    PubMed

    Moreno, Nancy; Flores-Angulo, Carlos; Villegas, Cecilia; Mora, Yuselin

    2016-12-01

    CYP2D6 is an important cytochrome P450 enzyme that plays an important role in the metabolism of about 25% of currently prescribed drugs. The presence of polymorphisms in the CYP2D6 gene may modulate enzyme level and activity, thereby affecting individual responses to pharmacological treatments. The most prevalent diseases in the admixed population from Venezuela are cardiovascular and cancer, whereas viral, bacterial and parasitic diseases, particularly malaria, are prevalent in Amerindian populations; in the treatment of these diseases, seve